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HomeMy WebLinkAboutSEPA EPIC-SA-15 - PARK PLACE - REZONE AND DEVELOPMENTPARK PLACE REZONE & DEVELOPMENT EPIGSA -15 ' 7 June 1978 CITY of TUKWILA OFFICE of COMMUNITY DEVELOPMENT M E M O R A N D U M TO: FROM: Kj FEIS Recipients toknes, OCD Director SUBJECT: Park Place Rezone FEIS Please find enclosed a copy of the Final Environmental Impact State- ment for the proposed Park Place rezone. The Tukwila City Council will be holding public hearings on this matter in the near future. No specific date has yet been scheduled. Thank you for your comments. KS /FNS /ch Enclosure 6230 Southcenter Boulevard • Tukwila, Washington 98188 • (206) 242 -2177 FINAL ENVIRONMENTAL IMPACT STATEMENT FOR PARK PLACE REZONE CITY OF TUKWILA In Compliance With: The State Environmental Policy Act of 1971 Chapter 43.21c, Revised Code of Washington SEPA Guidelines, Effective January 16, 19.76 Chapter 197 -10, Washington Administrative Code Date of Issue: June 6, 1978 Cost Per Copy: $4.50 INTRODUCTION Project Sponsor: Dick Gilroy Northward Development Company 1115 108th Avenue N.E. Bellevue, Washington 98004 Proposed Action: The sponsor is requesting that the City of Tukwila approve a rezone with conditions and general site plans in a Planned Unit Development format for a 15 -acre parcel.on the south face of Tukwila Hill to provide for 189 condominium units and 10 single - family building lots. Rezone request of the 15 -acre parcel will be broken into R -4, R -3, R -2 and R -1 9600 single - family parcels with major open space areas defining various residential densities. Project Location: On the south face of Tukwila Hill above Southcenter Boulevard and Southcenter shopping area. The project will be north and slightly west of the new Tukwila City Hall. The site is located between the westerly extension of South 151st Street and the easterly extension of South 153rd Street between 59th Avenue South and 62nd Avenue South. See Figures 1 and 3. Lead Agency: The City of Tukwila Responsible Official: Kjell Stoknes, Director Office of Community Development Contact Persons: Gary Crutchfield, Fred Satterstran,Tukwila Planning Department, 244 -6290 1 Principal Contributors/Location of Background Material: Environmental Analysis and Document Preparation: R. W. Thorpe and Associates 815 Seattle Tower Third and University Seattle, Washington 98101 623 -2935 Architecture and Site Planning: Len Milbrandt McClarty, Johnson, Associates, P.S. Inc. 16301 N.E. 8th Bellevue, Washington 98008 747 -4050 Geology and Soils: James Eaton, P.E. Eaton Engineers P.O. Box 126 Hobart, Washington Engineering, Utilities, Hydrology, and Surveying: Dave Halinen, P.E. Triad Associates 846 108th N.E. Bellevue, Washington 98004 454 -0711 Applications, Permits and Licenses Required Rezone approval, site plan approval, subdivision for single family units, clearing and grading permits, building permits, utility permits, certificates of occupancy. Location of EIS Background Data: Tukwila Planning Department, Tukwila City Hall (See Appendix G - References ) R. W. Thorpe and Associates, Seattle Date of Issue: June 6, 1978 Cost Per Copy: $4.50 RECIPIENTS OF THE DRAFT ENVIRONMENTAL IMPACT STATEMENT /Federal: Walter Jaspers U.S. Environmental Protection Region X 1200 6th Avenue Seattle, Washington 98101 /State: ✓ Office of the Governor Legislative Building Olympia, Washington 98504 V Department of Ecology c/o Dennis Lundblad,Head Environmental Review Olympia, Washington 98504 'John J. Fotheringham Agency South Central School District 41406 4640 South 144th Seattle, Washington 98168 ✓ King County Public Library (3) 4205 South 142nd Seattle, Washington 98168 Regional: Puget Sound Council of Governments Brian Beam, Environmental Planning Div. Grand Central on the Park Seattle, Washington 98104 Newspapers: Puget Sound Air Pollution Control L./Record Chronicle Agency V Seattle Times.- South End Addition A.R. Dammkoehler, Air Pollution Contro�Seattle Post Intelligencer Officer 410 West Harrison Street P.O. Box 9863 Seattle, Washington 98109 ✓ Municipality of Metropolitan Seattle Peter Machno, Manager - Environmental Planning 821 2nd Avenue Seattle, Washington 98104 King County Land Use Management Division Edward B. Sand W -217 King County Courthouse Seattle, Washington 98104 ✓ Kent Planning Agency James P. Harris, Planning Director P.O. Box 310, City Hall Kent, Washington 98031 Renton Planning Department Gordon Ericksen, Planning Director 200 Mill Avenue South Renton, Washington 98055 Dr. Richard Wade Seattle -King County Health Department 903 Public Safety Building Seattle, Washington 98104 City of Tukwila: Mayor - .Honorable Edward Bauch City Clerk (3) Fire Department Police Department Public Works Department Parks and Recreation Department City Attorney SEPA Public Information Center Planning Commission TABLE OF CONTENTS Introduction 1 Summary 6 The Proposed Action 6 Potential Direct and Indirect Environmental Impacts 9 Alternatives to the Proposal 13 *Measures Proposed to Mitigate or Eliminate Adverse Impacts13 Unavoidable Adverse Impacts .17 Description of the Proposal 20 Name of Project Sponsors 20 Location of the Project 20 Other Agencies Maintaining Files on the Project 20 Construction Phasing 20 Major Physical and Engineering Aspects of the Proposal 21 Relationship of the Proposal to Existing Comprehensive Land Use Plan and Zoning Regulations 26 Existing Conditions, Impacts and Mitigating Measures 32 Elements of the Physical Environment 34 Elements of the Social Environment 58 Remaining Adverse Impacts that Cannot be Mitigated 80 Alternatives to the Proposal 81 The Relationship Between Local Short -Term Uses of Man's Environment and Maintenance and Enhancement of Long -Term Productivity 86 Irreversible or Irretrievable Commitments of Resources 86 Appendices 87 *See for proposed conditions for approval of rezone and all development/building plans. Note: Summary only each section further explains and analyzes these measures. 4 FIGURES Number Title Page 1 Vicinity Map 7 2 Site Plan and Proposed Zoning 8 3a Neighborhood Zoning and Development Patterns - Existing22 3b Neighborhood Zoning and Development Patterns - Proposed23 4 Site Plan - Trails, Open Spaces, Circulation 24 5 Comprehensive Land Use PLan 27 6 Topography 36 7 Grading Plan 37 8 Existing Conditions 38 9 -1 Geologic Characteristics 39 9 -2 Soil Groups: Description and Characteristics 40 10 Existing Drainage 46 11 Drainage Plan 47 12 Water System 71 13 Sanitary Sewer System 71a 14 Site Sections 87 15 Elevations 88 16 Access and Circulation Alternatives E -2 TABLES Number Title 1 Proposed Zoning Areas and Densities 56 2 Population and Housing 59 5 A. The Proposed Action Project sponsors propose a rezone (with conditions) of the 14.7 - acre parcel which consists of lots 8, 9 and 10, Interurban Addi- tion to Seattle and site plan approval to allow for rezoning of currently R -1 and R -3 designated properties (see Figure 3) to R-4 (Low density multi - family), R-3 (3 &4 family units), R-2 (2 family) and R -1 9600 (single - family), as shown in Figure 2, subject to conditions and site plan approval as described below. The northeasterly 3.19 acres of the property is proposed for R -1 9600 zoning to be developed with 10 single - family detached sites, averaging 10,000+ square feet per lot. The northwesterly corner, containing 2.23 acres is proposed to be R -2 for two -unit townhouse structures and would contain 18 units. An open -space area con- taining 2.56 acres will be provided; delineating the.R -1, R-2, R -3 and R -4 areas. The R -3 property contains 3.15 acres of property and follows the general ridge line, as shown in Figure 6, Topogra- phy Map. This property is proposed for 32 units, in 8 buildings containing four units each. The balance of the property on the south and southwest, abutting existing R -4 and R -3 zoned property, would be developed under R -4 zoning to contain 139 units on 6.16 acres of ground. This area would contain a minimum of 209 parking stalls in order to fulfill the 1.5 parking spaces per dwelling unit requirement. The total proposal, then, would have 189 common-wall units and 10 detached single - family homes. All units are planned to be condo- minium, owner occupied units. The open -space areas that are in large tracts would be protected with restrictive covenants and a no -build zone imposed on the site plan approval. Access to the project would be primarily from the southeast corner via 62nd Avenue South (north of the access point to the new Tukwila City Hall), where 62nd joins South 153rd Street. Access for the 6 5, ak v • �,►,u • PARK e pi01O0• ..*.":111k• It ST WCITE f,. 1 /finnq •'CE /ITER 1?t o • Y DUNLAP . homes lea/ ;d/110n1.1 Cf1/ Pon t j 6600 � RAINIER � ssoo 0 ST or i St uri ff v• :•.io 411 SOUTHERN •'Y • sus sf HEIGHTS �t4�1 JLEYARD • PARK 4 ST ▪ OAK PARK [sr 5* 04 51 FIT . +,. ?7 :ST•1•uCu ti• - Vn11U..f11 • RE ERLY PARK • HAZEL It ;"7-) ARY LLEY ..,-,n,,,30 sl • SOUTH POINT 1 6000 //. ! ! t ` 1 y ,.,1 \ `ri o • L FSI. "± KENNYO COLEMAN POINT IL91Si 5 .j ►L �• a SC /0300 BRYN MAWR Bin/ • 500 .� : .-".1 !32 5? ' SOUTHLANO $lahU ►sl :„. o 51.116 St —y o rri Park ` CHELSEA --• ° PARK :ICC.n•,1 4. A. /Cs :16 _ . ST 1 100 1-4 n 4.••••••••••• 4). L.... • 300 „; • 1 . r...... 1Y BUM RIYERTIN HTS S 4f 44 ) 4 ?Mart 1S4 SI 40S, tTi J L RENT\ON Y HTS ; • SOUTH f -s ENTER�a .901\ VP w W.w' TH a »i• -- E SE 164 5T • J ! •1 4 NORTH w.. • 1 N ,�, S. .q. So •' �" � lets p • Oyf jBo1r Laie • • 1. lea .t•.. ••S1 Ang/eftake1//� 4) V1§ 6:74V-1----e. Q- ol . r _ .ti: S? V•I !`, mg INN lag 1111,01-1111111--111---11111-1111-01111-110-11.--101-4111--tridi single - family units would be east via South 151st, or north via 62nd Avenue or South by and 59th Avenue. The entire development would be phased over a two or three year period, building 50 to 75 units per year as the market dictates. Phasing would proceed from the south to the north under present plans. B. Potential Direct and Indirect Environmental Impacts 1. Elements of the Physical Environment Soils, Geology and Topography a. Localized erosion as areas are subjected to clearing and grading. b. Some cut and fill areas as portrayed in Figure 7, required for construction of proposed structures, roads and access points, with a net surplus of 4,000 cubic yards to be used in berms or removed fran the site (probable to a fill site in developing industrial /commercial areas). c. Compaction, alteration and over - covering of soils for construction facilities. d. Alteration of topography due to the required cut and fill. e. Removal of about 6,000 cubic yards of bedrock fran the southeast corner of the site, to be used elsewhere on the site. Air Quality a. Long -term increased emissions from site - generated vehicu- lar traffic, fireplace use and heating. b. Short -term construction- related increase in dust emissions fran construction equipment, open burning and blasting. Water Resources a. Same alteration of runoff quantity due to increased area of impervious surfaces, altering the flow characteristics in a year -round stream. b. Increased turbidity, petroleum product residues, nutrients and slightly elevated temperature in runoff. c. 'Potential diversionof groundwater movement. 9 Flora /Fauna a. Elimination of some trees and understory vegetation, par- ticularly from the south and westerly portions of the site. b. Removal of vegetation will result in reduction of wildlife habitat. c. Adverse impacts on downstream fisheries may result fran an increase in pollutants in the drainage basin. Noise a. Increase in on -site noise levels during construction, drawn out by proposed construction phasing. Some blasting will occur. b. Some increased traffic noise from site - generated volumes. c. Exposure of new residents of the site to highway noise currently in excess of recommended levels. Light and Glare a. Addition of artificial light sources in the project area. b. Increased quantity of traffic movements at night.' Land Use a. Commitment of the 15 -acre site to urban residential use. b. Increase in the intensity of land use by the provision of 139 units at 5 or more per building, 32 four -plex units, 18 duplex townhouse units and 10 single - family units for a total of 199 units. c. Compatible with or more site sensitive than apartment developments on the west and east and south of the subject property; provides transition zones fran existing devel- oped zones. d. Generally consistent with adopted comprehensive plan for the City. 10 a. Increase of 1,234+ vehicular trips per day to and from the proposed units including 100 trips to and from the single - family property via S. 151st Street and 62nd Avenue S., and 1134 trips to the south on 62nd Avenue S. from the multifamily units. Over 91% of total vehicle trips will be to south via 62nd Avenue S. b. An 11 per cent increase in the daily and peak hour traffic on Southcenter Boulevard which is currently 11,300 at 62nd Avenue Southeast (i.e., addition of 1,234 ADT's). c. A substantial increase in traffic volume on 62nd Avenue,' south of the site, from an estimated 400 to about 1,600 trips per day. d. Slightly increased ridership on Metro Transit Routes serv- ing the area. 11 e. Increased potential for conflicts and accidents from pedestrian, bicycle and'vehicular uses of road area. Public Services a. Increase of 10% or less in fire, police and aid service calls. b. The residences may contain a potential of 60 to 100 school age children, about half of whom will be in the elementary grades. c. Increased utilization of City, County and State parks and recreational facilities and programs near the project area. d. Increased private and public maintenance requirements for roads and'utilities. e. Increased demand on hospital services in the area. Utilities a. Increased use of electricity,, natural gas, telephone ser- vice, water, sanitary sewers, solid waste facilities. b. Storm water discharge will include provision for retention and pollution separation to minimize potential hazards. See Appendix A for detailed utility consumption figures. Energy Small, but incremental, increases in long -term use of energy resources at this site, including estimated consumption of about 400,000 kwh per month for electricity and 3000 to 4000 therms of natural gas. Human Health Proposed ponds may impact water quality if not maintained and remain free flowing. Aesthetics a. loss of natural features and replacement by human settle- ment and activities. 12 b. Potential impetus for development of similar character in the area. c. A change in the visual character of the area as seen from 1 -405 and Southcenter, significantly different from exist- ing development on the hillside. d. Creation of views for a majority of the units to the Green River Valley, Mt. Rainier and areas south of Tukwila. Risk of Explosion, Upset or Hazardous Emission Blasting may take place on southeast corner of site to remove part of an exposed bedrock formation. C. Alternatives to the Proposal 1. Use of site for single family (R -1) and fourplex (R -3) under existing zoning. 2. Maximum utilization of the property south and west of the ridge line for R -4 zoning, R -3 along the ridge line, the balance of the site in R -2 and open space. (See Figure 7.) 3. R -2 on Lot 8, R -3 on Lot 9, R -4 on Lot 10. (See Figure 3.) 4. All uses as proposed except the single - family area retaining as open space and either a covenant to keep as a natural area or deeded in fee to the City as passive open space area with a site for a water reservoir facility. 5. Modify size and configurations of proposed use zones. 6. No action. •D. Measures Proposed to Mitigate or Eliminate Adverse Impacts The following mitigating measures that are feasible and economi- cally practical with available technology have been suggested for mitigation or elimination of adverse impacts, including: Soils, Geology and Topography 1. Requirement for additional soil tests on building sites, and certification by qualified specialists of adequate foundation design for each structure. 13 2. Retention of storm runoff waters during and after construction to reduce water contamination by suspended silts and to reduce peak flow volumes. 3. Inclusion of no -build areas on steep slopes, storm water pond - ing areas and areas containing major groupings of vegetation. 4. Control of grading operations to avoid peak rainfall periods. 5. Replanting of exposed slopes. 6. Use of decks, cantilevering to minimum disturbance of steep slope areas. Traffic and Transportation 1.., Control of traffic flow through site design to provide major access to Southcenter Boulevard, an arterial, via South 62nd Street. 2. Allow site access to Northeast corner of site which goes through single - family areas, only for proposed single - family lots. 3. Cooperation with adjacent property owners to the south and east to improve 62nd Avenue S. and S. 153rd Street for visi- bility, width and general circulation. Air Quality 1. Specification of construction practices to minimize air pollution. 2. Implementation of sprinkling during construction to control dust. Water Resources 1. Use of landscaping to contain runoff and decrease velocity of overland flow. 2. Use of energy dissipating devices on drainage lines descending steep slopes. 3. Consideration of reduction of extent of impervious surfacing. 4. Use of siltation devices in the interim drainage system. 5. Proper use and maintenance of oil - separating devices in the storm drainage system. 14 6. Use buiding area and parking lot surface designs to detain water. Flora 1. Minimal and selective vegetation removal, particularly in the northeast and easterly portions of the site. 2. Predominant use of native species or compatible ornamental varieties in landscaping. 3. Hydroseeding of cut and fill areas within short time frame of grading. 4. Native growth protection easements and no-build zones placed on areas with slopes 25 per cent or greater and around exist- ing surface water holding ponds. Fauna 1. Maintain water habitat by proper use and maintenance of silta- tion and oil separation devices in the interim and permanent storm drainage system. 2: Phased development to allow existing wildlife to adjust and migrate. Noise 1. Incremental traffic noise impacts can be reduced by phasing project over a two- to three -year period. 2. Limitation of construction activities to normal working hours (i.e., 7 a.m. to 7 p.m.). 3. Use of heavily insulated buildings, double -pane windows, land- scaping, fences and earth berms as noise attenuating measures. Larger structures on south face of site will baffle some noise from I -405 and I -5. Light and Glare 1. Use of landscaping, fencing and building orientation to block headlight glare into dwelling units. 2. Site plan review by City Staff of orientation of parking areas, with respect to dwelling units. 15 Public Services 1. Provision of through - circulation corridors for emergency vehicles and police through the entire site; direct access to all buildings for fire - fighting equipment. 2. Development of recreational facilities and preservation of open space within the proposed development. (Recreational Space Plan required by Ord. #1040) 3. Stringent design requirements and equipment specifications for storm drainage control. 4. Requirement of regular maintenance program for privately owned roads and utilities. 5. Phasing of the project to delay impacts on the school district. 6. Cooperate with adjacent property owners and City for develop- ment of roads and public services in the area to serve the site. Utilities 1. Provision of hookups to existing dead -end water services to provide better fire flows and water service. 2. Linkage of other utilities to provide better service for the south face of Tukwila Hill. 3. Use of weather stripping; wall, floor and ceiling insulation and insulated glass in the dwelling units. 4. Use of common -wall construction as materials- and energy - saving devices. 5. Installation of water - saving devices in the dwelling units. Risk of Explosion, Upset or Hazardous Emission 1. Required procedures and safety standards will be followed if blasting operations are necessary including use of a licensed and bonded blasting firm. 2. Advance notice to adjacent property owners., 3. Provide bond to endimify for damages. 16 Aesthetics 1. Retention of natural vegetation to the maximum extent possible. 2. Alteration of building designs to minimize occurrence of typical rectangular structures. 3. Retention of natural areas and additional landscaping and screening between different use areas. 4.. Preservation of trees along ridge line will screen project from single - family homes to the north. 5. Add an additional 30 to 40 foot buffer zone along the north property line to the existing wooded area on the southerly perimeter of the school playfields. E. Unavoidable Adverse Impacts 1. Elements of the Physical Environment Soils, Geology, Topography 1. Potential erosion of soils during clearing and grading. 2. Extensive excavation of rock for roadway access at 62nd Avenue S.E. 3. Some alteration of topography by cuts and fills. Air. Quality 1. Some degradation of air quality in the project vicinity. 2. Increase in suspended particulates from fireplaces, resi- dential heating and construction activities. Water Resources 1. Increased runoff and decrease in water quality. 2. Slight alteration of stream flow characteristics in a year -round stream. Flora Removal of 50 percent of natural vegetation on the site. Fauna 1. Reduction of quality and quantity of wildlife habitat within the project area. 17 V 2. Reduced number and diversity of species on the site. 3. Potential impacts on 'water quality and downstream f ish habitat. Noise Increases in short -term noise levels during construction and minor increases in noise levels fran traffic after construc- tion greatest along 62nd Avenue, south of the site. Land Use Canmitment of 15 Acres to Urban Residential Use 2. Elements of the Social Environment Population 1. Population increase of approximately 450 to 500 residents on the site. 2. Addition of 60 to 100 pupils children to school district. Transportation/Circulation 1. Increase of 1,234 trips per day to and from the project, primarily at the southeast corner of the site. 2. Short term construction - related increase in local traffic volumes. 3. Traffic volumes on area streets after completion of pro- ject will increase substantially on 62nd Avenue south of the project and by minor amounts on other roads. 4. Increased potential for conflicts and accidents fran human and vehicular uses of area roads. Utilities Increased use of electricity, natural gas, telephone service, water, sanitary sewers, solid waste facilities. (See Appendix A for detailed utility consumption figures.) Energy Small, but incremental, increase in long -term use of energy resources. 18 Aesthetics 1. Loss of natural features and replacement by human settle- ment and activities. 2. Potential secondary development of similar character. 3. Visual character of area, as seen from I -405 and South - center will be significantly different from existing development on the hillside. 4. Creation of views for a majority of the units to the. Green River Valley, Mt. Rainier and areas in South King County. 19 II. DESCRIPTION OF THE PROPOSAL A. Proposal; Name of Project Sponsors The Northward Development. Company of Bellevue, Washington, re- quests approval of a rezone with certain conditions as set forth in Appendix F to allow for four new zoning areas: R -4, R-3, R -2, R- -1 9600 respectively. The areas,:as shown in Figure 2 would pro- vide for 134 condominium units. in the R-4 area and buildings rang- ing from 10 to 25 units per building with an accompanying 201 parking places. The R -4 would cover 6.16 acres. The R -3 zoning in the center portion of the site (3.15 acres) near the existing ridge line would. accommodate 32 units in eight 4 -plex buildings, two stories in height with parking for 64 cars. The northwest corner of the property, 2.23 acres near the existing R - -4 zoning on the Graden Smith property, would be developed with 9. duplex town- houses totaling 18 units, with attached covered parking places for each unit. The northeast corner of the property, 3.19 acres, would provide for 10 single - family, detached dwelling units, open space and a major retention pond for surface runoff. Separating the four areas would be 2.56 acres of open space areas protected by covenants from building or clearing. B. Location of the Project (See also Figure 1) The project is located on a 15 -acre site on the south face of Tukwila Hill in the City of Tukwila, northeast of the interchange of I -5 and I -405 south of Seattle. Legal description of the property is lots 8, 9 and 10 of Interurban Addition to Seattle. C. Other Agencies Maintaining Files on the Project There are no other agencies known to maintain a numbered file on the project. D. Construction Phasing The project is proposed to be phased for construction beginning with the R -4 portion of the property on the southwest, then moving 20 11 IRE ,,-- 5 sr. 6$7,I4 Am. T. 4;.ri `-c• 1?51 e,/. 67. 26 144 rt7; 1Jn V j 1: ant/4 97H 1.41. Cat° MN ommommil 'S /4 9TH '1. , 22 R-4 • -1, A -40- FIGURE 3A PROPOSED ZONING PATTERN R— 2 r-3 •-4 --„ C-1 4,? Detached Single Family Low Density Multiple Medium Density Multiple High Density Multiple 0 0 0 cil FIGURE 4 SITE PLAN TRAILS OPEN SPACE CIRCULATION that the site design is consistent with the goals and policies and the map portion of the recently adopted Tukwila Canprehensiv Land Use Policy Plan. The proposal would gradually reduce the density of dwelling units as one moves fran the south portion of the prop- erty northward and east. Steep slope areas are preserved in an open space system. Existing trails in the area are linked through the site. Major tree groupings have been identified as reserved for preservation in the conceptual site plan. Two small pond areas would be enlarged and utilized as a part of the open -space system for the collection and detention of peak storm runoffs. The more dense development is proposed to be restricted to the more level areas of the southerly portion with less existing vege- tation. Most of the desirable types of trees such as the coni- fers, large maples and associated understory will be left in nat- ural areas. Access is proposed for most units over South 62nd at the southeast corner of the site, with only the 10 single - family lots gaining access to the northeast. However, major cuts and fills with accompanying retaining walls will be required at the southeast corner of the site to provide access to that inter- section. The site plan provides for through circulation for emergency vehicles only, through push -down barricades. The entire project will be units for sale. No rental units are proposed as a part of the project. Community facilities will be provided for the entire project, a homeowners' association de- veloped and protective covenants, restrictions and conditions filed as a part of the overall condominium subdivision approval. Price range of the units will be determined by market forces, but generally range from $42,000 to $65,000. At present the site is totally undeveloped. Other than logging, past activities on the site were limited to provision of fill in the 62nd Street right -of -way at the northeast corner of the site for a distance of sane 200 to 300 feet. This partially impounds water flowing off the elementary school site resulting in a shall pond. 25 Clearing and grading of-approximately 50 percent of the site would be required to implement. the proposal, leaving major buffer zones along all four sides, particularly the north, east and west to screen the project from adjacent uses. The open space system along the easterly ridge line would both provide a linkage to the existing wooded and open space areas on both the school yard and the property lying to the east. F. Relationship of the Proposal to Existing Comprehensive Land Use Plan and Zoning Regulations 1. Tukwila Comprehensive Land Use Policy Plan The recently adopted Comprehensive Plan contains several ele- ments, including a Goals and Policies section and a map that serve as a land use guideline to assist the City's review bodies and staff in evaluating zoning applications and land use matters. As depicted in Figure 5 the site is divided into three as follows: The southwest corner is high density resi- dential (over 16 units per acre) the central portion and majority of the site medium density residential (7 to 16 units /acre) and the northeast corner low density (0 to 6 units /acre). The ridge line is used as a natural demarcation between medium and low density. The proposed site plan and proposed development have been designed to be as consistent as possible with the map, and the directions given to the previous property owners by the City Council, Planning Commission and City staff during the cony prehensive planning process. The plans also reflect the Goals and Policies section of the Plan as summarized below. Residential Element: Section 1: Neighborhood Objectives and Policies Objective 1, Policy 1: Buffer zone boundaries are based on topographic features. 26 0 LOW DENSITY RESIDENTIAL (1-6 DU/AC) 1E3 MEDIUM DENSITY RESIDENTIAL (7-16 DU/AC) HIGH DENSITY RESIDENTIAL (17+ DU/AC) OFFICE ID COMMERCIAL 0 LIGHT INDUSTRIAL ELI HEAVY INDUSTRIAL 0 PUBLIC FACILITIES O PARKS AND OPEN SPACE SITE SPECIAL DEVELOPMENT CONSIDERATI REFERS TOAREAS Of STEEP SUMS, WATER SURRICE, AND ILOOCULTURAL LAW:G.1M DESIONATION DON NOT PRECLUDE DEVELOPMENT; FLOWER, ff DEPICTS AREAS WHERE URBAN DEVELOPMENT MUST RESPOND SENSff1VELY 1 CERTNN ENVIROWENTAL FACTORS. PLANNING AREA BOUNDARY mum CITY BOUNDARY // "nun ium •'mum 111111111111111111 //////// Tin FIGURE 5 PRELIMINARY LAND USE PLAN 111 7M7EIL& Pi.aaHHOHO &N)-& 27 Policy 2: Subject property has a park and school playfield on the north and the applicant proposes buffer areas on the north and east to separate them from undeveloped areas. Policy 4: Objectively, vehicular traffic related to medium and high density units can be channeled to the south through apartment and commercial zones. Access to arterials is direct via 62nd Ave. So. (Note: Use of through lane for fire access must have access controlled with breakdown barricade to meet this policy. Objective 2, Policy 1: The proposed rezone and site plan approval, utilizing a vary- ing density of development, would provide for a medium density transition area between high and low density residential areas. Objective 2, Policy 2: This development would be located functionally convenient to primary arterial streets, shopping, employment and other facilities within the Tukwila planning area. Objective 3: Maintenance of buffer areas on the north and east, particu- larly the steep slope area, will provide compatibility with this objective. In addition, the following items as incor- porated into the proposal are responsive to policies in this section: Policy 1. Screening of adjacent uses. Policy 3. Undergrounding of all utilities. Policy 4. Maintenance of natural open space areas. Policy 5. Provision of guest and recreational vehicle parking. 28 Policy 6. Provision of trails to link activity nodes in the area. Policy 7. Encouragement of recreational open space within multi - family development. Section 2: Housing Objectives and Policies Objective 1, Policy 1: With the proposed development, because of its size (i.e.: 15 acres), it is possible to encourage housing development with a diversity of housing types. Duplexes, townhouses and four - plexes are envisioned on the less dense portions of the prop- erty, and the R-4 area provides a mix of condominium units with 2 and 3 bedrooms. Ten single family detached units are proposed. Policy 2: Townhouses, condominiums and single family lots are proposed for the site - all owner occupied. The proposal has been developed to reflect and be compatible . with the following Objectives and Policies: Objective 2, Policy 3: Insulation, insulated glass, and building siting will be used to reduce impact of freeway and aircraft noise. Element Goals General Goals '2, 5, 6, 8 , Natural Elements 1, 2, 3 Open Space 1, 2 Residence 1, 2, 3 Transportation /Utilities 1, 2, 3, 4 29 Element Objective Goals Natural Environment 1 1, 2, 3 3 1, 2, 3, 4 4 1, 3, 4 5 1 6 1 8 Open Space 1 1, 2, 3, 4, 6 2 1, 3, 4, 5, 6, 7 3 2 Residence (See Previous Text) Transportation 1 1, 2, 4, 5, 6, 7, 9, 10, 11, 12 3 1, 2 6 3, 7, 8 Utilities 2 2, 4, 5, 6 Sanitary Sewer 5 4, 5 Storm Water Systems 6 1, 2, 4 7 1, 2 Underground Utilities 8 1, 4, 5, 7 The following goals may be inconsistent with the application as presently proposed. Other policies and objectives not listed were considered not applicable. Goals General Goals: None Natural Environment: None Open Space: 3 - provide recreational opportunities for all people of Tukwila Residence: None Transportation: None Objectives /Policies Obj. /Pol.. Natural Environment 2 -1 Retain wooded hillsides for wild- life 3 -1 Some limited development may occur in areas of 20 to 25% slope, how- ever none in excess of 25% 30 Natural Environment 6 -2 Some rock outcroppings may be modified or removed 8 Some onsite studies have provided environmental data that may be different than that of the City's environmental data bank. Open Space 2 -4 Some areas of existing trails may be rerouted by development and public access restricted.. 3 -3 No trail easement for public access are proposed at present Residence 3 -1 No low income housing is proposed and in the 199 units 3 -2 Transportation 1 -1 Some conflict between parking and access may occur. 1 -4 No public dedication of rights-of- way is proposed except in single family subdivision 6-4 Trails, walkways may not be planned. for handicapped 8 -7 Utilities to link existing services may cause some disruption of natural areas. 2. Zoning Code The proposed uses will comply with the appropriate sections of the Zoning Code (Title 18, TMC) for R -4, R -3, R -2, and R -1 9600 classifications. A11 density, bulk requirements, site coverage, parking and other requirements have been reviewed and incorporated in the plans. 3. Building /Fire Code Provisions of the UBC and Fire Codes will be observed and changes made if necessary to comply. 31 III.. EXISTING CONDITIONS, IMPACTS AND MITIGATING MEASURES INDEX OF ELEMENTS OF THE ENVIRONMENT A. Elements of the Physical Environment Earth Geology 34 Soils 34 Topography 34 Unique physical features 34 Erosion 34 Accretion/avulsion NA Air Air Quality 42 Odor NA Microclimate NA Water Surface water movement 45 Runoff /absorption 45 Floods NA Surface water quantity 48 Surface water quality 48 Groundwater quantity 48 Groundwater quality 48 Public water supplies 70 Flora Numbers or diversity of species 50 Unique species 50 Agricultural crops NA Fauna Numbers or diversity of species 52 Unique species 52 Barriers and /or corridors 52 Fish or wildlife habitat 52 Noise 53 Light and Glare 55 Land Use 55 Natural Resources 57 Rate of use 57 Nonrenewable resources 57 Risk of Explosion or Hazardous Emissions 58 32 B. Elements of the Social Environment Population 58 Housing 58 Transportation/circulation Vehicular transportation generated 60 Parking facilities 60 Transportation systems 61 Movement /circulation of people or goods 61 Waterborne, rail and air traffic NA Traffic hazards 62 Public Services Fire 68 Police 6A Schools 68 Parks or other recreational facilities . 69 Maintenance 70 Other governmental services 70 Energy Amount required 73 Source /availability 73 Utilities Energy 73 Communications 73 Water 73 Sewer 73 Storm water 74 Solid waste Human Health (including mental health) Aesthetics 78 Recreation 66 Archeological /historical 79 Additional Population Characteristics Economic Factors 33 A. Elements of the Physical Environment 1. Earth a. Existing. Conditions Geology and Soils A ground reconnaisance of the site was conducted by a soils engineer (see Appendix A for report). Shallow glacial till, weathered on the upper two or three feet, grades downward into a glacial sand and gravel formation. A bedrock formation crops, out on the southeast property corner. Both bedrock and till provide excellent founda- tion strength. The till appears to be stable, with no evidence of sliding. Soils on the site are not analyzed in the Soils Conserva- tion Service's survey of King County, other than as gen- eralized "Urban Soils." The thin till soils observed on the site probably have a low productivity potential other than for forest. No unusual soils conditions were obser- ved, except for the exposed bedrock, which poses no prob- lem to development except difficulty of excavation. Topography The site has wide ranges of topography and slope with a ridge line as depicted in Figure 6, running from the northwest corner of the site southeasterly to the east property line. Elevation of this ridge line varies from 230' to 255.6', but generally averages 240' in height. From this ridge line, the property falls off to a low point near elevation 140' in the northeast corner and along the existing drainage channel. The property also falls off to the southerly property line, at roughly 180'. The westerly property 1 ine drops from 230' on the north- west to 165' on the southwest. The average slope from the ridge line to the northeast corner is 21 per cent and the average slope from the ridge line to the southwest corner is 12 per cent. The slope, ridge line and two low points 34 where some ponding occurs are depicted in Figure 6 - topography and 10 - drainage basins. b. Impacts Geology and Soils As noted below, a considerable amount of soils relocation will take place on the site, with cuts of 20,000 cubic yards, balanced by 16,000 cubic yards of fill. Approxi- mately 4,000 cubic yards of excess material will be used in earth berms or exported from the site. The bedrock outcropping will also be reduced for the southeasterly roadway entrance. Most of the rock is expected to be used on the site. The impact of the soils relocation on site will be related to the topography. Till soils are highly erodable if exposed on steep slopes. The stability of cuts and fills, as well as groundwater will be critical at the foundation locations. Topography Grading operations should have a range of effects on the topography. Significant excavation will occur at the southeast corner of the site to accommodate the access point. Total excavation of this area will be approxi- mately 6,000 cubic yards, largely bedrock. In certain areas, as depicted in Figure.7, cuts and /or fills will occur in order to provide for building pads, parking areas and roadways as a part of the overall site development. The proposed buildings would utilize existing contours such that foundation excavation would be minimal. The general estimates of cut and fill shown in Appendix C indicate that approximately 20,000 cubic yards of material will be excavated and approximately 16,000 cubic yards. of that material used for fill. The bedrock cuts can be 35 0' AHdV1100d0z ONIISIXd I • 7 1....70 ti ,... ., . 6... • .., . . L.." c ..0 . • _.1 I ..... ey;tt ,_„...i..._,....,....,„:„....4,:_.r....r. ,,,.„....„7„,.... , , „... . r' e• i , #_---,,/,-- 1 , / / 0 •,..: ., —,...- H 0 t't xi la.•••■,• 1 ! , , ‘1 , , . , , , / • 1 tefI, I i7 l . s'..)/ I , ! ,0 •' - f /.—.1 *..• f ./ t-I ..... . ./ .4 „ • k / ( ,".' i —‘— r , ( 4 '.-"8.' 7 . o.:, 0...ct.4-.7.„0 ;..r - ..".. ., —f.. - . • , . 4. g-•-.V 5•- i'•.s■ ) N ' ."..S/ )- ..• ; .,t . / . 1O4 .. / .0 . P 0 . . 0 ' ‘-7 *,,„„ 7,. • ,.i.4, ,•• . ,'1- - .'.,.. I' —,, ' ji• i7 , 1r "-:.• .7,-'. 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A . ..0.' .... ... ., • • --• h., — • • _.........- 7 / ' ,', ,i• ,---. 6 • -- % ' e. ---4' "- .. \k . ,.,_!: __4■.- :■ .■ a—L.4j r :, —ii,.. r '',k,f...k. li",.._•1'..—_, 00 —; — --- ----- fli— - --- .r.---- --:....,.."... .. , Yi -..! ---3.... ' -- - 0,..7"/ -"------ __ • ----. #. ''' --i,,;---------.. 2,4., , .../ . R , ;■,`...„ . ...........k ..' ' 1 .,.1 ; .. ' ' ' . . , • _.• 1 I. ' •. 0.• • ••••,..—,-;;;._.:„ ,•. ..A _,_: ....iz .1.• ..,..'. . t1•• . _...0 „' _ at, _ , -A, • . ., r. k A re', I • • ./.0 - -. . •.... _. .___ 1 Leadi DE3CF/PT/ON agIfill.(&47.•• rm., drwrfar, .eirerael. .r.••••■• MIII77.4., PM./ /0.47450 Awn, snow. SIC7.9.,EN 7r..0C7V • vt,-.141 7,7getp.0%.10.Ne. G,•• 37 Irr , • • A?T [ r -.• t, r'1 A • co,.: ems (1 • ur !..4'• • 01 1 907E 925.00 eiazz 211r 62ND AVE. 80. - .ti- -. .. iJ —AREA OF TOTAL VEGETATION RETENTION SITE PLAN OF EXISTING CONDITIONS MAR NOT MYE*= 77 w 7m c** u* 7qur� r** .,wn, 77 a 77c*7*7ru. 7714. :. unworn P.M. Mni u w. MD r�Norms n 777.7* m.o. n** uMnc MD.pu a4 .aua 17 m.wr. venom moron. 7..* n roan 15 7nWWru NEGATIVE In*n. FIGURE 9 -1 GEOLOGIC CHARACTERISTICS IN TUKWILA PLANNING AREA C = J. c m x ' '0 J C) 0 ct 0 Features Foundation Stability 1 Seismic Stability' Slope Stability Alluvium (Qa) Laid down by rivers after retreat of glacier. Primarily silt, clay, with some peat. ,; . Lacustrine deposits (Qic) Deposits laid down by great lake in Duwamish Valley when glacier blocked drainage to the north. Silts and clays. Efik . Outwash deposits (Qvo) Ground moraine laid down by Vashon glacier which has been washed by streams and melting ice. Sand and gravel. O O Ground moraine (Qvt) Also called Vashon till. This is the material which fell out of the ice as the Vashon glacier melted back into Canada. Compact mixture of clay, sand, gravel, and boulders. O O O Glacial, non- glacial deposits (Qu) Glacial and nonglacial materials laid down prior to Vashon glaciation. Undifferentiated de- posits of sand, silt, clay, gravel and till. O 0 Bedrock (TpTb) Includes sedimentary and volcanic rocks which formed in preglacial times. Folded sedimentary rocks of Renton Form- ation. Also includes intruded basalt. O O O GOOD (:) FAIR POOR IAdopted from: Preliminary Geologic Map of Seattle and Vicinity, Washington, U.S. Geological Survey, 1962; Donal Mu.11ineaux, Geology of the Renton, Auburn, and Black Diamond Quadrangles, King County, (Geological Survey Professional Paper) No. 672, 1970; and An Ecdlogical Study of the Kent Lowland, Kent Planning Department, 1971. 39 FIG. 9 -2 SOIL GROUPS: DESCRIPTIONS AND CHARACTERISTICS TUKWILA PLANNING AREA Source: Soil Conservation Service, U.S. Department of Agriculture, Soil Survey of King County, Washington, 1973. 40 utilized for roadway subsurfaces. Wherever possible, topsoils can be stockpiled for use in landscaping, berms and other surface treatment following construction. In some instances excavation for foundation and parking areas will be fairly extensive to accommodate conventional foun- dations. Significant grading and cuts and fills will be required to provide a roadway linkage for emergency ve- hicles from the northeast corner to the central portion of the site. Road grades will range from 2 per cent to 14 per cent except the fire lane linkage which will be 16 %. The entrance grade is planned to not exceed 12 per cent. Existing land contours will be altered by excavation, and relocation of fill material ,on the project site. No materials are to be imported and only excess fill mater- ials exported. Excavated materials will be balanced on the site during preparation for construction. Erosion On grades which exceed 8 per cent through the site for long distances increased runoff could create soils slip- page potentials. Eroded sentiments carried by runoff could cause turbidity in the stream that runs through the site. c. Mitigating Measures Geology and Soils Installation of siltation basins, drainage velocity dissi- pators and foundation drainage systems could mitigate the adverse impacts of soil erosion and reduce the potential for soils slippage. Restricting grading operations to periods of dry weather and replanting exposed slopes could reduce soil erosion. Installation and maintenance of temporary and permanent drainage control structures could reduce the sediment load that might enter the natural stream system. 41 Detailed soil borings and analysis on all building loca- 7----\/-----1 tions should be undertaken by qualified soils engineers and consideration be given to rearranging proposed build- ings if soil conditions dictate. The soils and slopes to be encountered are not thought to be unusual for the area and are commonly built upon safely, provided engineering recommendations are followed. A detailed engineer's report on foundations for each phase will be supplied with final building and grading plans for that phase, together with recommendations on standing cuts or slopes, filling materials, compaction and drainage systems. Zbpography Use of rockeries and retaining walls could reduce the extent of topographic alteration. Use of pole or pier - type foundations as well as architectural design varia- tions on steep -slope areas could decrease grading re- quirements and thus mitigate adverse impacts on existing topography. Reducing the extent of development would reduce grading requirements. 2. Air Quality a. Existing Conditions The most significant factor affecting ambient air quality in the vicinity of the proposed project is automobile traffic and airplane traffic from Sea -Tac Airport, Boeing Field and Renton Field. The site is located on the south face of Tukwila Hill, which is bound on the south by I -405 and on the west by I -5. Sampling of particulates and sulfur dioxide has been carried out at Southcenter since late 1976. Air pollutants contained in vehicular exhaust emissions include carbon monoxide (CO), hydrocarbons (HC), and 42 oxides of nitrogen (N0x), of which carbon monoxide is the pollutant of most concern. Carbon monoxide levels were monitored during 6 weeks in January and February of 1977. Maximum 1 -hour concentrations did not exceed 11.5 parts per million (ppm) at any time. This is one -third of the maximum 1 -hour standard of 35 ppm. Eight hour averages were under 4 ppm. Traffic congestion, characterized by a large number of slow- moving or idling vehicles, occasionally results in high CO levels in the area, particulary on days when the wind is light and stagnation or inversion conditions exist in the Green River Valley. Prevailing wind is from the southwest in winter and the northwest in summer. The average daily traffic volume along Southcenter Boulevard is 11,000 vehicles per day, on I -405 66,400, with vehicles concentrated periodically around Southcenter. Suspended particulates are another source for air pollu- tion, chiefly responsible for reduced visibility in the Puget Sound region. Sampling developed by the Puget Sound Air Pollution Control Agency. (PSAPCA) indicated suspended particulate levels ranging around 45 mg per cubic meter (ug /m3) in 1976. Compared to 1975 maps for the same pa -- rameter, Tukwila and King County in general appear to be experiencing an increase in suspended particulate levels in the atmosphere; in 1975, the same area showed an annual mean of 33 ug /m3. Traffic along the above mentioned roads can affect pollut- ant level in the project area, particularly during periods of low wind velocity. -Vehicular exhaust fumes tend to follow the upward slope of the site and odors from this source would be most noticeable with the onset of morning vehicular traffic. Airplane exhausts occur in the area and are a part of the general air quality. 43 b. Impacts Unless an increase in congestion at intersections is caused, air pollutants generated as a result of this pro- ject should not have a significant effect on local air quality. The peak hour traffic levels, in the range of 125 vehicles per hour, slightly more than two cars per minute, on 62nd Avenue South, should not cause any great increase in concentrations in the area. The rise in pol- lutants in the significant areas, along Southcenter Boule- vard and I -405, may rise in proportion to the traffic levels. This project should add less than 1% to the traf- fic through that corridor. (Estimating 70% of the site's A.D.T. (794) allocated to Southcenter Parkway Boulevard, between 62nd Avenue and the Southcenter access overpass, where total A.D.T. is nearly 80,000 (combination of I -405 and Southcenter Boulevard).) No significant increase in the probability of violations of local air quality stand- ards is therefore expected as a result of this project. c. Mitigating Measures Vehicular exhaust emissions should be reduced as federal vehicle :mission standards became effective and older vehicles are replaced. If peak hour traffic volumes on Southcenter Boulevard result in significant . congestion at the intersection of 62nd Avenue South and Southcenter Boulevard, provision of turning lanes may be considered. Although not within the scope of this project to effect, widening of I -405 in this area could reduce congestion and improve air quality. Sprinkling could be implemented during construction per- iods to reduce airborne dust. 44 3. Hydrology a. Existing Conditions Stormwater runoff generated by the site currently drains in three distinct directions. The northeast portion of the site drains into a well - defined drainage swale. This swale, which also receives drainage from the developed area to the north, broadens to form a shallow pond about one foot deep and then runs from north to south eventually emptying into the I -405 storm drainage system. As well as conveying stormwater runoff, a small base flow of approxi- mately 0.1 cfs exists in this swale and acts as the source of the shallow pond. The south portion of the site drains into the currently undeveloped property to the south. There are no distint drainage swales in this area. Runoff travels essentially as sheet flow until it is intercepted by S. 154th Street and routed into the I -405 storm drainage system. A shallow depression which has a maximum depth of approxi- mately 3 feet exists adjacent to the site's west boundary. Approximately 2 1/2 acres of the site as well as 1 1/2 acres west of the site (the only offsite area draining into the site) drain into this depression. This drainage is apparently the source of standing water at the depres- sion which is probably seasonally intermittent. b. Impact The existing drainage patterns at the site will be basi- cally retainied. Stormwater runoff from the northeast portion of the site (which is proposed for the least in- tensive development) will pass through oil -water separator catch basins and then be conveyed to the existing drainage swale at the east boundary. As a result peak flow rates will increase in the swale. However at points A and B as shown on the Existing Drainage map, the peak 10 -year re- 45 Jr\ FIGURE 10 \ \\H I . EXISTING DRAINAGE (77/,//2 J 3 47^.37: I ) \ \- • l‘t\ tia • \ \, c\ ( /6I• Sr `\v-\\\ \\\ \ _J -NAYINW dr: \SECe3,11VP P3 PIE DIMINACE BASIN LIT 0711CAI TLIAWIL4 CI TY MU arzie cawfucrcry 1\ ASteCIATES---- e Joe roo roo /—` • • FIGURE 11 )\11i ■ DRAINAGE PLAN . ( / I ( \ A 1 • ? \ • \ 3.147"' ST /-\ MOuri Dalt/Ail TNAU/ OK I WATER SEPARATORS - MD CONVEY rfl asnlie tavmse motif \ \\\ \ ACP'sr c. ) () r • ss weft* COVVEYANCE ROUI1N6 MAU DITINTION PACI111111, AND OISCHARDI PROP0110 110RAI DRAIN SITE . m PROPOSED snqM DRAW • IM if PART Of KA° AY! 5 INAIMIRMeN11J ,ne Ez,w &MN r • • "orlon, or. e3,IWP23.V,RIE t (ty4fR Cav0auCTIN) / - / 0 00 t , oo 000 .01 ASSOCIATES • turn interval flows should increase by only 30% and 20 %, respectively (from 7.7 cfs to 10.1 cfs at A and from 9.9 cfs to 12.1 cfs'at B). Due to the relatively steep chan- nel slopes the existing capacity of the downstream system should be adequate to accommodate this flow rate increase. Because of the more intensive proposed development of the south portion of the site, stormwater detention facilities will be provided to limit the 10 -year peak discharge to the south to approximately the existing 1.2 cfs 10 -year peak flow rate. Discharge from these facilities, will probably be made into a storm sewer line which should be built at 62nd Avenue South in conjunction with improvement of that street to facilitate this and neighboring develop- ments. Such a storm sewer would then discharge into the I -405 system at Southcenter Parkway. The depression along the west boundary will probably be developed as a shallow pond for use as an amenity to the project. However runoff from a portion of the area cur- rently tributary to this depression may be routed into the detention facilities at the south portion of the site. Clearing, grading and construction of extensive areas that will be covered with impervious surface materials will significantly alter existing runoff and absorption char- acteristics. Site runoff could be expected to increase by more than five times in some small areas. Absorption of precipitation will also diminish signif i- cantly as a result of interception by parking areas, roads, rooftops, and other impervious surfaces. Approxi- mately 60 per cent of the R-4 dwelling areas and 40 per cent of the duplex and single - family areas would be covered by such surfaces. Average site coverage through- out the project would be approximately 50 per cent. 48 Surface water quantity,would be adversely affected to the extent that runoff is increased and absorption is decreas- ed. Reduced absorption could result in lower low- stream flows. Clearing and grading activities will cause erosion of site soils during construction periods. Eroded sediments could enter the stream as runoff and result in turbidity. Run- off from parking areas; and roads could contain petroleum product residues. In addition, runoff from impervious surfaces would have slightly increased .temperatures and nutrient levels. The adverse impacts on the water quality would be most significant from runoff during seasonal low flow periods. Deep excavations required for placement of large buildings on the hillsides in the project area could intercept groundwater movement. c. Mitigating Measures Runoff /Absorption Landscaping features, such as berms, gardens, and porous walkways, as well as grassy areas and natural areas that would induce vegetation, could detain runoff and decrease the velocity of overland flow, substantially reducing peak runoff volumes. Use of the two existing ponding areas to detain runoff and detention facilities in the more dense parts of the proposal could decrease runoff and increase absorption. In sane areas where feasible, the combination of splash blocks and bored recharge shafts might be utili- zed to increase absorption. Perforated steel piping for underground portions of roof drains could permit greater absorption and reduce surface runoff. Reduction of the extent of impervious surfacing could be encouraged to decrease the quantity and rate of runoff. 49 Surface Water Quantity Mitigating Measures suggested by Triad Associates in Appendix B for increasing absorption and detention could mitigate the potential impact of peak and reduced low flows. Surface Water Quality Use of siltation devices as a part of interim drainage system during construction could reduce the potential for turbidity and sedimentation in the stream. The storm drainage system could be equipped with oil - separating devices which, if properly maintained, would reduce the potential for petroleum product residues to enter surface waters. 4. Flora a. Existing Conditions Like many of the areas surrounding the Green River Valley on the plateaus, the site of the proposed development was densely forested in its native state prior to intensive logging that occurred in the early 1900s. However, sig- nificant groupings of vegetation are located on the site, including Douglas Fir, Big Leaf Maple, Western Hemlock, Western Red Cedar, Alder, as the dominant species of the native coniferous /broadleaf mixed forest. The site appears to have undergone additional clearing since the original logging activities and, at the present time, a number of firs of the 8- to 14 -inch category and some larger Big Leaf Maples are scattered throughout the site - in some cases in significant stands. The understory in- cludes grass, blackberries, salal, Oregon grape and other shrubs and grasses native to the mixed forest. The major groupings of trees are shown on the site inventory and site plan as well as the topographic survey (Figures 4, 6 and 8). 50 The site is typical of many of the plateau regions above the Green River Valley, and a site visitation by a land scape architect did not find any rare or endangered species occurring within the proposed development site. b. Impacts Same portions of the site will be extensively cleared for development of the project, namely the western portions with those areas shown on the site plan (Figure 8) to be retained. These areas contain large Firs and Maples. The vegetation around the level areas of the two ponds will be retained as a part of those retention ponds. The project proponents, the architect, landscape architect and other consultants have expressed intent to preserve large trees within the development to the maximum extent possible. It might be noted that from the inventories and visual surveys of the site, much of the significant vegetation viewed from below the site on I -405 and other areas occurs in the steep -slope areas, where it will be retained. Clearing and grading requirements for construction will result in removal of vegetation from some areas, ranging from 40 to 80 per cent of isolated areas. Diversity of natural floral species can be expected to be reduced as a result of such a substantial reduction in the quantity of natural vegetation. c. Mitigating Measures Minimal and selective vegetation removal should be encour- aged particularly northerly of the ridge line, where the most significant area of natural vegetation presently occurs, as well as those areas around the drainage ponds. Replanting and landscape requirements should use native species and compatible ornamental varieties. Additional inventorying of vegetation should occur at the time of surveying for various buildings. Consideration should 51 then be given to slightly altering the orientation or siting of buildings, parking, walkways and other devel- opment in order to save significant groupings of trees. Major buffer areas along the ridge line, in the drainage areas and on the steep slopes should be preserved in their natural state, guaranteeed by covenants. 5. Fauna a. Existing Conditions The existing character of the undeveloped site offers limited habitat for large animals in the heavily urbanized area. However, rodents, such as mountain beaver, hare, mice, shrews and moles occur on the site. The drainage channel and bordering vegetation may attract same species such as racoon from adjacent wetland areas. In addition songbirds and some upland game birds such as quai frequent the site. No unique, threatened or endangered wildlife species are known to occur in the project area; however, encroaching suburban development is limiting the available habitat for resident species, particularly large mammals or game birds. No fish are known to occur in the drainage channel nearby due to its intermittent flows and blockages at some downstream locations. b. Impacts Substantial site clearing and the introduction of a large human population will have the most significant impact particularly on the southerly portion of the property. Displaced wildlife may try to relocate in adjacent for- ested areas or the valley areas nearby. However, since incremental development throughout the area is reducing available wildlife habitat, adjacent areas can be con- sidered to be at their carrying capacities for wildlife. The result will be a net reduction in species diversity and the number of individuals of each species that will be present in the area. 52 c. Mitigation Preservation of the steep slope, watercourse areas and pond areas should substantially preserve this habitat for species. The restoration of sane vegetation in the area in the form of landscaping would provide a future habitat for those species which are compatible with an urban environment (i.e., songbirds, squirrels, etc.). The open space system will provide a corridor for the movement of animals between the park and open space area and other areas in the general vicinity. 6. Noise a. Existing Conditions The site currently contributes no measurable noise to the environment. Major noise factors in the area are the two major highways and their interchange. The interchange itself is 1/4 to 1/2 mile distant, while the roadway of Interstate 405 passes within 800 feet of the southwest corner of the site. This freeway alone has peak hour volumes that should generate noise levels above 70 deci- bels (dBA) at least 10% of the time (L10) . This is sup- ported by readings of sound levels above 70 dBA at the south side of the Tukwila apartments, immediately west of this site and closer to the major interchange. This noise level is at or above the level which Federal Highway Administration standards define as the maximum level acceptable in residential areas near highways. Local and Federal standards also indicate this as a level likely to cause annoyance and interfering with speech out of doors. The two houses south. of the site on 62nd Avenue should be receiving average peak (L10) noise levels close to 80 dBA out of doors. b. Impacts The development will generate noise levels on and off the site due to traffic to and from the site. The single- 53 family area, with access to the north,.will generate only a small amount of,traffic noise. The multi - family devel- opment, with 189 units gaining access to the south via 62nd Avenue, would raise the noise generated by, traffic on that road alone by a.substantial amount. A rise of 10 decibels above.the existing ambient noise levels. is nor- mally considered to be significant, causing annoyance. However, the potential receptor areas will already be receiving noise from the highways in excess of 70 dBA (L10), and median noise levels (L50) substantially ,in excess of the 60 dBA standard. The noise level at 50 feet from 62nd Avenue; generated by this project plus the San Juan Apartments and the anticipated project to the south- east, would probably not exceed 50 dBA (L50). It will therefore probably not be perceived above ambient noise levels fran the highway. Construction on the site will create noise peaks, with substantial use of heavy equipment, pneumatic tools and same blasting to move a substantial amount of earth, hardpan clay and bedrock. Such equipment can generate noise levels of 65 to 85 dBA at 50 feet. The areas most exposed to noise impact fran this site will be the Tukwila and San Juan Apartments, plus apartments under construc- tion along the west border of the property. Zb the north is the Tukwila Elementary School playfield, which will receive less noise, as intensive activity will take place mainly on the southerly half of the site, behind the ridge line. Noise peaks may be reduced by up to 6 dBA for each doubling of distance from machinery, so that noise from the center of the site would be reduced by distance by 18 dBA on adjacent properties. Earthmoving near the site perimeters will have the greatest impact. The construc- tion period is estimated to include less than three months of heavy earthmoving activity in each of the three phases. Thereafter, heavy machinery noise peaks will be reduced and replaced by general construction noise and trucks. 54 c. Mitigation Construction noises will occur in phases at different locations on the site. At any one time, the majority of the potential noise receptors around the site would be a substantial distance removed from the noise generating activity. Further mitigation could be achieved by: 1. the use and maintenance of properly operating mufflers and quieting devices as well as use of quietest avail- able machinery and equipment 2. the use of. electric equipment in preference to gas, diesel or pneumatic machinery 3. locating construction equipment .as' far fran nearby noise sensitive properties as possible 4'. shutting off idling equipment 5. limitation of construction hours to coincide with the normal workday period, e.g. 8:00 a.m. to 6:00 p.m. 6. scheduling the noisiest operations near the middle of the day, and notifying nearby residents whenever ex- tremely noisy work will be occurring. 7. the use of permanent or portable barriers around point noise sources. 7. Light and Glare a. Existing Conditions, None b. Impacts Traffic entering and exiting the site at night could cast light upon sane nearby residences from headlights. Sane light will be visible from the residences themselves from areas off the site. c. Mitigaton Much on site light will not spill off the site due to topography and the vegetation being left. Proper orienta- tion of buildings and use of berms and landscaping along 55 roads and entrances can minimize light spill off the site as well as between areas of the site itself. Parking -lot lighting should be kept downward - directed, at a low level to prevent glare. 8. Land Use In that the request is for a zoning reclassification this subject has been covered in detail in Section II -F - Rela- tionship to Existing Plans and Regulations. In addition the following conditions and impacts are reviewed. a. Existing Conditions The site is vacant with no improvements; same timber exists on the site, primarily 8 to 10 inch Douglas firs. In addition some Maples and Cedars of significant size are scattered on the site. The site at present with its R-3 and R-1 12,000 zoning could theoretically support 30 to 35 single family lots and 44 to 58 apartments or condominiums in a series of 4 -plex buildings. The former comprehensive plan called for multi- family on the entire site with no density clarification (i.e. nearby properties are R -1, R-3, R -4 and RMH. (See Figures 2, 3, 3A). Apartment densities in the area range as follows: San Juan - 16 /acre, Tukwila - 22 /acre, Southcenter - 26/ acre, La Vista - 36 /acre, Stardust - 41 /acre. This plan was changed in 1977 and the present map and policies described in Section II -F will guide land use decisions and rezone applications. The requested change in terms of density is summarized in the table below. 56 Table 1 Proposed Zoning Areas and Densities Location Zone on Site No. of Units Zoning Acres DU /AC Code Comprehensive Plan R -4 Southwest 134 R -3 South of 32 Ridge Line R -2 Northwest 18 R -1 Northeast 10 6.16 22.70 43 3.15 10.20 18 2.23 8.07 10 3.19 3.14 3 -5 17+ 7 -16 7 -16 1 -6 The resultant site coverage with buildings is 17.8% and other impervious surfaces 30.0% for a total of 47.8% site coverage. 52.2% is in open space and landscaped areas. b. Impacts The 14.7 acres of undeveloped land will be committed to multifamily and single family uses, plus a 2.56 acre open space tract. The proposal would provide a range of 3.19 to 20.70 DU's /acre, averaging 13.19 units /acre. Impacts to adjacent properties include: loss of vegetation and open space, increased traffic, use of recreation and public facilities. c. Mitigation Alternative site designs and densities could reduce asso- ciated impacts. The declining densities of the Planned Unit Development approach provide a variety of housing opportunities while providing transition zones to existing adjacent development as well as within the site. The relative impact is .reduced by.deyeloping at a lower den - sity than existing on adjacent properties. 9. Natural Resources a. Existing Conditions No natural resources are on the site, other than trees, and none are being consumed. 57 b. Impacts Wood, cement, asphalt and energy resources will be util- ized on the site. The project will not require any un- usual amount of these to be consumed on site that would not be consumed by construction on other sites, except for the consumption of fuel in the excavation and fill proce- dures. c. Mitigation Reduction in size of project would reduce materials consumption. 10. Risk of Upset or Hazardous Conditions a. Existing Conditions- None applicable. b. Impacts. The required blasting of bedrock will require the use of explosives on site for a brief period. Though impacts normally only include sudden, but brief low- frequency noise peaks and vibration, there are small but inherent hazards of damage from improper handling or blasting. c. Mitigation All possible safety procedures for explosives handling and use will be followed. B. Elements of the Social Environment 1. Population and 2. Housing a. Existing Conditions Housing in the City.of.kwila is predominantly in multi- family structures (66 %) and has shown the development pattern of "boom -and- bust" in housing development typical of apartment- construction cycles. Housing composition is summarized in the table below. Average persons per occu- pied housing unit has averaged about 2.2, closer to the average for apartments than for detached units (2.7 to 3.0). Residents have statistically been younger, but near 58 or above the regional average in incomes and education, again typical of an apartment area. b. Impacts The statistical housing and population impacts are sum- marized below in Table 2. The "1978 Housing Estimate" is from the City of Tukwila Planning Department's estimate for April 1, 1978, beginning fran the 1977 Census of the City as a base. The 1978 figure has not been certified by the State of Washington. Table 2 Population and Housing -- Tukwila Single- 5 + .units Total family Duplex Triplex 4 -Plex Bldg. 1977 Census 1685 574 22 3 48 1038 1978 Estimate 1693 578 22 3 52 1038 Added by Project (Est. 1982) 199 10 18 32 139 As % of 1978 11.5 1.7 81.8 61.5 12.9 Est. population / unitl (2.5) 3.0 3.0 2.2 2.2 Est. population added 498 30 54 70 300 1Per observations of similar projects. Figures assume maximum high number in order to calculate maximum impact. The maximum population impact is estimated at 498 persons, assuming no vacancies. Actual population will probably be lower, with same vacant units. A statistical average for family size has not been established for condaninium units in this area, so the figures..for the single - family and duplex units were the average for owner- occupied units in the county (currently mostly. in single family dwellings) and the balance at the average for renter- occupied dwellings. 59 Relating the proposal to the existing housing mix in Tukwila, the project is adding proportionately less to the supply of single - family housing and to large multi -unit structures. It is adding a far greater proportion• to the currently low supply of two- and four -unit structures. Though the trend towards multi - family structures in Tukwila is being continued, the condominium ownerships will tend to increase the proportion of owner - occupied dwellings in Tukwila. c. Mitigation The population and housing impacts will be spread out over three years. 3. Transportation /Circulation a. Existing Conditions (See Figures 2, 3 and 4) Area Streets The project area is touched at the northeast and southeast corner by existing developed roadway. A right of way along the, easterly boundary in the 62nd Avenue South alignment is unopened from South 151st Street at the ° northeast corner and South 153rd Street at the southeast corner. South 152nd is open to a point approximately 200 feet from the west boundary line of the proposed devel- opment. At one time South 152nd Street divided the prop- erty between lots 8 and 9 but was vacated several years ago. Access to the northeast corner would be to a well - improved right of way with curbs, gutters and sidewalks that joins 65th Avenue South, carrying traffic from that area south to Southcenter Boulevard and north to the bal- ance of Tukwila, the Fire Station, Police Station, schools and other facilities. However, as much of this area is single - family, this proposal limits access to this area in order to minimize impacts on that street corridor. The southeast corner, 62nd Avenue South, is an improved two - lane road of approximately 18 feet in width with 3 to 4 60 foot shoulders and open drainage ditches. The roadway is proposed to be developed at its southernly terminus along the last 200 to 250 ,feet to serve the new City Hall pre- sently under construction. South 153rd Street -south of the San Juan Apartments (i.e. at the southeast corner of the project site) is an improved two -lane private road. Severe visibility problems occur at the intersection of South 153rd and 62nd Avenue S. Driveway cuts to serve the subject property will consider the elevation of this cor- ner. Any future development of the property to the south east of that intersection, i.e. a portion of lot 16 of Interurban Addition known as the. Black and Caldwell prop=. erty will be required to dedicate right -of -way and widen both 62nd Avenue S.E. and South 153rd. The development'of the proposed project, if concurrent with that of the Black property and of portions of lot 11, may provide opportuni- ties for joint efforts to improve 62nd Avenue South from the conclusion'of the city's improvements to South 153rd Street. Tb the west of the subject property South 152nd Street is opened to serve existing and developing apartment com- plexes in the area. The existing facility and proposed improvements have been the subject of significant con- sideration and discussion by adjacent property owners, the city and the county. This road is narrow with no curbs, gutters or sidewalks and is heavily impacted by existing development. The proposed project would have an outlet to 152nd Street; however, it would be proposed only'for fire - lane access with a break -down barricade. The site planning and circulation plans call for carrying all of the multi - family dwelling units' traffic to the southeast corner where it reaches theexisting arterial (Southcenter Boulevard) and Freeway interchanges with I -405 and I -5 by the most direct route. 61 Transit Metro transit provides several routes linking Southcenter Boulevard, Southcenter Shopping Center and Tukwila with other valley communities such as Renton, Kent, Auburn, nearby facilities such as Seattle - Tacoma International Airport and employment centers as well as dbtntown Seattle and east side communities such as Bellevue. Several tran- sit lines serve Southcenter, and are within walking dis- tance of the proposed project. b. Impacts The proposed development is projected to generate approxi- mately 1,234 vehicular trips per day. See Appendix C. The impact on South 151rd Street from 10 family dwelling units, assuming 10 trips per household per day, would be 100 trips per day. Assuming the worst case situation of 20 per cent of the trips during a peak hour this would represent 20 trips or one every 3 minutes. Other times of the day would average 5 trips per hour or one every 12 minutes, assuming all trips occurred in a 14 hour time period. The internal circulation system of the project will carry unit traffic through the 4 -plex area and through the more dense portions of the project to 62nd Avenue South. These traffic impacts are projected to be, at 6 ADTs per dwelling unit, approximately 1,134 ADTs. This traffic as it is carried down 62nd Avenue South to Southcenter Boulevard should have a minimal impact on the carrying capacity of Southcenter Boulevard and represents a 10 percent increase on that facility. Sane congestion could occur on 62nd Avenue S. and at the point where those traffic flows combine with city hall traffic. At present the adjacent San Juan Apartment development and additional units could generate in the vicinity of 240 to 300 ADTs. Proposed developments on the Black property could generate 300 to 600 ADTs. Of those instances some 62 of that traffic may choose to utilize South 153rd Street to join 65th Avenue east of those developments. Assuming 50 per cent of traffic turns each way, half of the traffic generated by those two projects would be carried on 62nd Avenue South. The remaining property that would be avail- able for development of a significant size is lot 11, pre- sently owned by Mr. Ehmke. The resultant development level on that site is unknown at this point; however, assuming that this property was developed at 18 to 22 units per acre consistent with comprehensive plan, its 6 acres would yield 108 to 132 units and in turn 648 to 792 171 ADTs. Assuming this entire development would lain n access over 62nd Avenue S. this would result in a fairly signifi- cant impact on 62nd Avenue South. '1 tal generated traffic of these four areas on 62nd Avenue plus two existing houses were totaled they would equal 2069 to i-394 ADT's (an 18 per cent increase on Southcenter Boulevard).22%3 Transit At present there is no formula for estimating the use of transit services by residents of the developments or the existing developments in the area. Other multi - family projects typically generate sane demand on the services. The availability of extensive local service as well as service to downtown Seattle is expected to attract riders from the proposed project area. Construction of shelters near the city hall to serve that facility and potential projects on the Tukwila hill including the Northward Development proposal would serve to promote greater transit usage. c. Mitigating Measures The proponent is suggesting cooperation among the four major property owners in the area to assess the impacts of proposed and existing development on 62nd Avenue South and cooperate with the city to provide improvements for auto, 63 pedestrian and bicycle traffic in the area. This would benefit all properties through improved traffic circula- tion and minimize traffic friction and conflicts. Resur- facing and widening of the roads, installation of under- ground storm drainage, curbs, gutters and a sidewalk may be conditions of approval of all pending and future devel- opment plans in the area. Participation in an LID may be the mechanism for approving this type of development.. I f further studies show a need. for improved traffic control at the intersection of. South 63rd and Southcenter Boule- vard, installation of those facilities may be warranted. Transit Car pooling and the use of Metro services promoted through literature in the condominiums' offices and recreational facilities could reduce peak hour and average daily traf- fic generation for the development. Circulation Alternatives As portrayed in Figure 16 in Appendix E there were a number of various access and circulation patterns studied prior to the proposed layout, circulation, access and parking configuration. Although as shown in Figure 16, many variations can be analyzed. There are three basic alternatives to the proposed access at 62nd Avenue South and South 153rd Street, with emergency vehicle and service vehicle access to south 152nd Street on the west and South 151st Street at 62nd Avenue South in the northeast corner. Those alternatives are listed below with a brief analysis of the benefits (positive impacts) and costs (negative impacts) to the proposed project, neighborhood and com- munity as a whole. 1. Through Circulation to S. 152nd Street; Emergency only to S. 151st Street 64 Benefits a. Improved circulation for existing and proposed apartments west of site. (Total existing and potential units 500+--projected AD►r's of 4000 to 4400) b. More direct access to City Hall, Southcenter Bou- levard for Apartment. c. Fire, police, city maintenance access should be included. (Note: Provided in part under pro- posal.) d. Improved access to Hill from fire, police stations. (Note: reduces response time +2 minutes.) Impacts a. Potential high percentage of 4000 -4400 ADT's going through condominium project. b. Project split - separates units from recreation, open space. Creates arterial thru project site.. c. Poor control - crosses path of school children going to school and recreational facilities. d. Transfers access problems at S. 152nd and McAdam Road to 153rd and 62nd Avenue South and also to 62nd Avenue South and Southcenter Boulevard near City Hall. e. Mixes RMH traffic with R-2 and potentially R-1 area traffic. 2. Through Circulation to North 151st Street at 62nd Avenue South; South 152nd Street limited access Benefits a. Faster emergency vehicle access to project (very limited improved response . time). b. More direct access between new City Hall and existing facilities. 65 c. More direct access for single family areas to Southcenter Boulevard, Southcenter, Freeway on ramps, etc. d. Long term commitment for through circulation. e. Improved access to utilities. f. Reduced traffic on 65th Avenue South. Impacts a. Access of multifamily to south to single family areas. b. Loss of open space areas, vegetation, stream area due to need for extensive slope cuts and fills. c. Crossing of pedestrian ways, trails, access to school, parks, play areas. d. Provision of major circulatioin route through project, dividing sane areas from recreational facilities, open space, trails, etc. e. Loss of "neighborhood feeling" in project and in area. f. Loss of single family lot or lots in proposed plat; loss of .open space acreage, buffer zone between single family and R -2 areas. 3. Through Circulation all three access points - 62nd Avenue South at S. 153rd; South 152nd Street on west; 62nd Avenue South at South 151st Street. This alter- native may include opening 62nd Avenue South right of way as well. Benefits a. Faster emergency vehicle access to area from fire station. b. Unlimited circulation on South face of Tukwila Hill for all areas and all directions. c. Very limited improvement in access to utilities. 66 Impacts a. Access by all apartments to project (condominium area) and single family areas to north. b. Increased traffic on all area roads except west- bound of South 152nd Street. - c. Loss of open space, trails, vegetation, land use buffer zone and delineation of single family and condominium and multifamily areas. d. Potential loss of 62nd Avenue South trail - or the present walking experience and environment. e. Increased soils, hydrology, air - quality, noise impact on area. f. This alternative would require a redesign of Park Place project with potential change in mix of uses , and unit types. g. Project proposal retains emergency vehicle access from both points and can be designed for mainten- ance vehilcle access. h. Adverse effects on aesthetics of proposed- project, reduced potential for significant landscaped areas. i. Adverse economic impacts may influence unit type, quality and resultant sale price as well as future potential for project. j. Road completion requirements may impact project phasing and the ability to secure construction financing. These benefits and costs are briefly mentioned in Section V: Alternatives to the Proposal as a cross reference to emphasize this relatively important section of the Final Impact Statement. 4. Public Services. a. Existing Conditibins Fire Protection The proposed development, is in the City and would be served by the City Fire Department. Tukwila has two fire stations, one in Andover Park which serves the industrial area and one at 59th Avenue South and S. 147th Street. Estimated response time would be 1.0 to 2.5 minutes to the northeast corner and 2.5 to 4.0 minutes to the southeast corner of the proposed project. Fire flow at the margins of the site is currently estimated to be adequate to serve the project. Additional information will be developed following zoning review to support building permit appli- cations. Emergency medical aid vehicles are available at the ZUk- wila City Hall site. Police Protection Police protection is located at the same site of the fire station near the old city hall. The Tukwila Police De- partment patrols and responds to emergency calls in the vicinity of the proposed project. The ratio of police officers to population in the City of Tukwila is presently at or slightly above the national average for a city of its size, in part due to the large ca1unercial and indus- trial areas which require additional protection and security. Schools The proposed Northward Development project is within the attendance areas of South Central School District. Tuk- wila Elementary School is contiguous to and directly north of South 144th Street. Junior and Senior High Schools are within a walking distance of 10 to 20 minutes via a free- way overpass, but students fran the proposed development 68 would•be provided bus service.to the junior and senior high (Source: South Central School District,. Transporta- tion Services; personal catununication,•by. telephone con- versation) The capacities and present enrollment of the schools leaves sane spaces in each which would adequately handle the projected enrollment levels of this project. Southgate Elementary School is scheduled for closure this year due to falling enrollment. Total district elementary enrollment for the 1978 -79 school year is estimated at 827. This will be handled by. the three remaining elemen- tary schools; with a combined official capacity of 1,025. "Comfortable" capacity, reserving rooms for music and remedial reading, is 875. The proposal is. not anticipated to be accommodated. in Tukwila Elementary with no bussing required. School enrollment has been consistently dropping in the district, due to changes in resident characteristics in the area, and the static housing supply. The annual enrollment in 1979 -80 is expected to equal the previous year, and a climb in enrollment is expected in 1981 -82, when enrollment may be expected to be generated by this project. "Comfortable" capacity is expected to be reached in the 1983 -84 school year (School District estimates). Parks and Recreation Parks, recreation and open space areas in Tukwila, in particular around the Tukwila Hill area, include 5.3 acres at Tukwila Park adjacent to 65th Avenue South, a 52 acre regional King County park.along.the Green River near 1 -405 and Foster Golf Course along Green River near Interurban' Avenue. School playgrounds provide additional active recreational area and the undeveloped areas in portions of 69 the city provide passive open space areas. However, with- in the city limits of Tukwila there are only 6.3 acres in city ownership used . for park or recreational purposes, somewhat limited for a city of this size. Additional open space and recreational facilities would compliment that limited city resource. Maintenance. Roads and storm drainage systems in the vicinity of the project area are presently maintained by the city of Tuk- wila. The city and Metro (the Municipality of Metropoli- tan Seattle) maintain sanitary sewer systems. The water system in the area is maintained by the city and utilizes City of Seattle water. b. Impacts Fire Protection Approximately 250 fire and aid calls per year are gen- erated per 1,000 residents in the Tukwila area. Zbtal population of the proposed development is projected to be no greater than 450 persons. Therefore in,a worst case situation approximately 120 fire and emergency calls per year may occur fran the project area. In fact, fire calls will probably be much lower than average in the new build- ings, with required fire safety devices. In addition the average reflects a very high incidence of non - residential fires. Service for the development is not expected to have any adverse impact on existing manpower or equipment. Police Protection Residential uses have a moderate impact on police pro- tective services in the form of burglaries and emergen- cies. Non - emergency calls are perhaps the most time - consuming requirement of multiple - family developments. The circulation and street configuration can both posi- tively and adversely affect police emergency response 70 time. Discussions with the Police Chief indicate that through circulation is desirable in order to serve emer- gency vehicles and promote quick response time. However, through circulation can provide the. adverse element of allowing burglars in adjacent property more direct and unimpeded escape routes when pursued by police personnel. This proposed development is not expected' to directly result in the requirement for additional police personnel or equipment. However, the cumulative effects of in- creased development on this hillside may necessitate addi- tional expenditures in the future. Schools Due to the phasing of the proposed project, maximum school impacts are not expected until the 1981 -82 school year, when school planning presently anticipates growth. At a "worst case" estimate, this proposal could generate 50 elementary school students, bringing the elementary schools to their "ccznfortable" capacity, as estimated by the district. Other developments could take elementary enrollments higher. The District's strategy at that time could include reopening Southgate Elementary, expanding another school or going beyond "comfortable" capacity. The predictions for secondary - school enrollments were not carried beyond cohort - survival projections. It is assumed that up to 50 students could be added, with some impact on the capacity of those schools. Parks and Recreation Residents of the proposed development could be expected to utilize the park and recreational facilities in the city and in the Green River valley, playgrounds, and to a lesser extent the golf course, fishing opportunities in 71 the Green River Valley and nearby lakes as ,well as other community facilities of adjacent communities. Maintenance The proposed. development would have.. private roads and storm drainage facilities for which the owner of the de- velopment would have maintenance responsibility. Repair of surfaces, cleaning of .pollution control devices, main- tenance of storm drainage and utilities on site would be required of the developer and future home owners. All public roads and utilities in the area would require maintenance by the City with associated rise in personnel and material costs. c. Mitigating Measures Police Protection The police department should be provided with a copy of the final approved development plan locating new street addresses in the project area.- Fire Protection All fire code and building code requirements will be met. Future site plan approval should consider access to indi- vidual areas of the project. Linking of water mains in the area some of which are presently dead ends (i.e. 152nd Street) should improve fire flows. If future studies of fire flows warrant additional mitigating measures the interior common areas of buildings could have sprinklers. All units are proposed to have smoke alarms. • Parks and Recreation The development proposal includes 2.56 acres of open space facilities with an additional recreational area including a building, two tennis courts, a swimming pool and large areas of trees and open space are scattered throughout the 72 site. The trail system would provide for jogging, walking and passive recreation, mitigating the need for these facilities in adjacent areas. Maintenance Stringent storm drainage design requirements could reduce maintenance. Regular maintenance of the privately owned drainage facilities could reduce maintenance required for public portions of the system. 5. Utilities a. Existing Conditions Energy Puget Sound Power and Light would serve the proposed de- velopment with electrical energy. The proposed condomin- ium units would be "all electric" and are estimated to use approximate ]1y 2,000 kWH of electricity per unit per month (conversations with Puget Power). Use of natural gas may be considers -d for heating the swimming pool. The gas mains, according to phone conversations with Washington Natural Gas, are available at the northeast corner of the property and can be extended to the southeast corner in developed rights of way. Communications The project area is served by Pacific Northwest Bell and hookups are available at the southwest and northwest corners of the property. Water . The city of Tukwila provides water service. for the prop erty as shown in Figure 12. Water is available at the northeast corner through an existing 8 -inch main located in the 152nd street right of way. A 6 -inch water main is also available, presently serving the. Tukwila Apartments at the southwest corner of the site. The Public Works 73 'NI OWN S !AMR AK'N .1.2f° (VIM* 6" VTR MAN • ....... ) ...- , ) . '• ,‘ ... ‘ \ ' \ %J i 1; 1 is k ; ( ., , ..... . . t . , \ ........ . I \ , ' MIIIIII1S. -----. , ___.....-c.„:- . • // MIRAN ONO CONSUMPTION • 4; ape.)timi■ CALM'S . 0 \:,. '\ I 4' --TrICI" ST ) 1 • • / —runvey city MIL / / IOW& C04:.;IR.CTON) - • TRIAD ASSOCIATES .) L. ItYrrali ns 23 A / ,R1C t 1 400 7 FIGURE 13 ,, , vat MANY AND 01,PLEV•lbrai unni ,Ariffird oisomme-?dopeA)\ ' ' ) ((■)*\ J----\■ \: \ ,\-i. 1 ) ( ralit.natt Cc;s.hoeVil g- 16i UNITS I Avetece DM? OSOIARGet • \ \ -37,4,00 4,4Z Soo ctra • i\ TRIAD ASSOCIATES 4S-eVu 4M-O7? eky • PROPOSf0 trSill JEW MAW I'M Of Me Of goo • WES thowovemereal Fos y '—TiJJiWil4 CITY AuLt nismos "SVC IWO cotsmerovi / twit aav 400 NOM Department suggests linking these various water mains to provide continuous loops, better water service and better pressure for fire - fighting purposes. • Sewer The City of Tukwila and Metro provide sanitary sewers in the vicinity of the project. An existing 8 -inch sanitary sewer is at the northeast corner. An existing 8 -inch line serves the new City Hall property on 62nd Avenue South. The latter line would be required to be extended as a part of 62nd Avenue South improvements, as shown in the sani- tary sewer system, Figure 13. Any sewer extension would be through an LID or Developers extension agreement and sized to fit engineering requirements (i.e. 8" is preliminary). This proposed sewer improvement would serve three major properties in the area. Storm Sewer No publicly owned storm drainage system exists in the project area at the present time. Runoff from major por- tions of the site travels to the east down an existing drainage channel past the new.city hall and under South - center Parkway to a point where it joins.an existing stream bed that flows easterly along I -405 into the Green River. Peak storm water flows for the 10 year storm will bee detained onsite. These flows will be released to the existing drainage channel. In addition some peak flows from the project could be taken care of in an improved drainage system along the .improved 62nd Avenue South right -of -way as a secondary system-to the main drainage channel. b. Impacts Assuming that the proposed dwelling units will be all electric and will require approximately 2,000 kwh of electricity per month (average), implementation of the 76 project would result in the increase in monthly electrical requirements for the site approximately 398,000 kwh at full development. According to Puget Sound Power and Light, they have adequate energy resources and equipment in the present service area and would expand its local services as necessary to accommodate future growth. Communications Telephone communication service for this development is estimated to require 254 cable pairs. According to Pacific Northwest Bell,' this can be accommodated within existing systems. Water Implementation of the:.proposal will require construction of water mains through the site linking existing facili- ties at three corners and the west side of the site. Water consumption within the project area will increase usage in the,area approximately 67,200 to 74,700 gpd. The increased requirements for water services is not expected to have an adverse impact on existing water supply or the proposed system through the site. Sewer The proposed development could be expected to generate approximately 44,800 to 49,800 gpd of sewer (see Appendix C). This'increase in sewage flow from the project area is not expected to have an adverse impact on sanitary sewer in the vicinity according to the. public works department. Storm Drainage Drainage within the proposed development would be col- lected in surface collection systems including retention areas and released at a slower rate into existing drainage channels or in improved storm drainage along 62nd Avenue South. 77 c. Mitigating Measures Energy Discussions with the architect indicate that energy con - servation measures (as well as noise limiting measures) such as weather stripping, wall ceiling and floor insula- tion and insulated windows will be provided in the pro- posed dwelling units to reduce heat loss. Common wall construction is proposed for most of the units and will reduce energy requirements for residential heating. Water and Sewer The installation of water saving devices in new dwelling units could reduce water consumption and sewerage flows. 6. Aesthetics a. Existing Conditions The natural condition of the site with extensive tree cover and other vegetation provides a visual amenity to the Southcenter area, adjacent properties and the entire south face of Tukwila Hill. A small, shallow, year -round stream meanders through a portion of the site and along its easterly perimeter. The topography of the site, its location near a school and other factors make it one of the more desirable undeveloped sites in Tukwila.. Many portions of properties around the site particularly on the west and south have been almost totally cleared of vegetation making this site an unusual one with only the site to the southeast and scene to the northeast in similar condition. b. Impacts Approximately 50 percent of the site would be developed with condominiums, parking driveways, trails and other facilities. It would have an impact on views to the site, particularly on views from Southcenter Boulevard'and 78 it — or r r — r we — 250 230 210 190 170 150 250 _ 250 _ 210 110 n0 150 EAST - WEST CROSS • SECTION EAST - WEST CROSS SECTION NORTH - SOUTH CROSS SECTION FIGURE 14 UNOT A FRONT' ELEVATION 00. 0 UNIFY A - BOOS ELEVATION 1/4 r--- ! - .TOP OF PLATE • GRADE 1' I !! • --4 UPPER LEVEL .1; , UNOT 13 - FO%0INIT ELEVATION 1/4' LOWER LEVEL LIVING ROOM i 1! 1 , 1111.1 I ELDNOT B - EAR 1 Luna i L VAT° ON FIGURE 15-B OT B - HOME EL; E VAT 0 ON 1/4" r- ■ IIIIIIIIIII 11 RA I mmHg o rr mum mum i a !I . III TYUDOCAIL fifFNLMIJT C L IEVAT0®frul ®LEDCc3 44✓.La> Vb I' -O• CO'(11oR •C• UNIT dnLClNmb VoMILAII) Of (BLEVW U a ®N D3311.®® �1 (fjLS • vs.- .. -o • Om MONT ®L a VATOOTM BUCKER 1 a Els ' 6COLfi: V■•• 0-O& r, tfRO AL. Sow CER.EIVATOONJ -. 03114013a o M, a ye •- II -01 FIGURE 15 —C properties to the south.,. west and , east . :A more detailed analysis of this impact is contained in the graphics that follow this section.. c. Mitigating Measures,:, Retention of natural vegetation ..to. the maximum..extent possible and generous landscaping can reduce the impact of hard surfaces (roads, fences, buildings) and preserve a certain degree of the forest character of the site. Build- ing designs are proposed that take advantage of the slop- ing of terrain on the site to avoid the repetition of rectangular building facades. The large buildings have been turned at an angle to appear less massive from prop- erties to the west, south and east. The ridge line and existing vegetation have been used to obscure the common-. wall developments from the northwest, north, and north- east. The architect has utilized existing topography and major groupings of vegetation wherever possible to nestle the buildings into the. site. The four -plex and duplex town- house units will be incorporated into existing vegetation using exterior wood siding with natural earth tones to be compatible with the site. Larger buildings will have scene wood details and some stucco finishing. There will be extensive landscaping, rockeries and other facilities to provide a natural transition for the existing topography. In addition, screening easements, retention of the vege- tation through restrictive covenants and the use of densely planted vegetation perimeters will be provided between different use areas proposed for the site. 83 7. Archaeological /Historical_ Resources a. Existing Conditions A review of City planning documents, County planning docu- ments and 'discussions with State agencies uncovered no known archaeological or historical resources in the pro - posed project area. 84 IV. REMAINING ADVERSE IMPACTS THAT CANNOT BE MITIGATED Modification of the •topography will take -place on site to accommodate buildings and roads, requiring movement ,of a large quantity of soils. B. Storm water runoff will increase ;in quantity, except that peak flows will be lowered by detection facilities. Some increase in pollutants in the runoff will take ,place, including oils and grease, heavy metals, sediment and nutrients. C. Animal habitat will- be removed as vegetation is removed from a large portion of the site. Only species tolerant of human activities will remain. Occupants driven from the site will largely perish. D. Residential uses will be established in an area subject to high peak levels of- noise. E. The 14.7 -acre site will be committed to urban residential land • use, at a greater density than under the existing. F. An increase in the potential population of the site, as a net effect of the rezone, of an estimated 230 persons; an absolute increase, due to the projected construction, of up to 450 persons, over a three -year period. G. Traffic will be substantially increased on 62nd Avenue South, from the Southeast, corner of the site to- Southcenter Boulevard, and increased by 10 per cent on Southcenter Boulevard, east of the overpass to Southcenter: H. There will be a general increase in demand for public services, in proportion to the rise in population anticipated (about 15 per cent). 85 V. ALTERNATIVES TO THE PROPOSAL The following alternatives are summarized on page 13. These alterna- tives are ones that are readily available under existing or proposed zoning and are modifications of the proposal developed by Northward that would satisfy the general goals and intent of their proposal. 1. Use of the site for single - family (R-1) and fourplex (R-3) under existing zoning. As shown in Figure 3 half of lot 10 is presently zoned R -3, which would allow for fourplexes with the balance of the property being R -1, 12,000 square foot lots. The zoning was developed at the time the city swas incorporated and carried on the site in the absence of any zoning request' on the property. The former compre- hensive plan showed this entire area for apartments without any density clarification. Under the former comprehensive plan prop- erties contiguous to and west of the subject property were rezoned to R -4 and RMH. Properties to the southeast were rezoned to R -4. At present there is an application on the property to the south to change the zoning from R -3 to R -4. The revised comprehensive plan calls for a break in densities and uses over the site ranging from high density residential (M/F) on the southwest, medium density residential (M/F) in the middle portions and low density residen- tial (S /F) on the northeast corner. Preliminary studies conducted by site planners for the Tukwila Associates group indicated that single - family development of the site would be possible, however, extensive costs would be asso- ciated in terms of providing roads and access and the impacts on the site might be much more significant than that of clustered housing with open space areas provided for in.steep slope areas, drainage areas and difficult soil areas. Disamenities such as noise, location near very dense, existing apartment complexes made the decision to utilize the property for single family an unat- tractive one to the property owners and potential users who would develop the property. 86 2. Maximum utilization of.the property south and west of the ridge line for R-4-zoning, R -3 along the ridge line, the balance of the site in R -2 and open space. This alternative has been presented as part of a previous request to the Planning Commission and Council via waiver from provisions of Resolution 489 •(interim land -use regulations). Under this proposal the southwest portion of the property would be used for an R -4 apartment complex at a density of approximately 28 to 30 units per acre. for 6 to.6 -1/2 acres. The R -3 zoning would provide for .townhouse condominiums at 16 to 20 units per acre over 6 to 6 -1/2 acres. Duplex -and triplex townhouses would•be_ developed at 8 to 10 units per acre; with approximately 2 acres of the balance of the property in open space. The proposal is summarized in the table below. SUMMARY OF USES AND DENSITIES Area Housing Type Density /Acre Acres Total Units 1 Apartments /Townhouses 30 6.0 -6.5 180 - 195 2 Townhouses /Condaniniums 16 - 20 6.0 -6.5 108 - 130 3 Duplex & Triplex Townhouses 8 - 10 2.2 -3.2 16 - 32 304 - 356 It should be noted that this is a modification Pram previous con- siderations .on this property by Tukwila Associates, original owners. The previous application had suggested 28 to 30 units per acre or a density approaching 450 total units. The modified ap- plication discussed a range of. 24 to 29 units per acre or 304 to 356 units. At the time of this application, the Comprehensive Plan had not been .adopted and the City was acting under Resolution 489. .At that time some of the densities proposed were felt to be inconsistent with the emerging comprehensive plan. The applica- tion was .denied with direction given to modify the application following the adoption of the Comprehensive Plan. 87 3. Utilization of existing zoning classifications on individual lots as follows: R-2 on Lot 8; R-3 on Lot 9 and R-4 on Lot 10. The splitting of these three formerly platted areas, approximately 5 acres in each lot, would provide for the application of a separ- ate zoning district or classification on each lot. A transition zone could be established on each property from adjacent proper- ties to the north and south. The zoning classification would provide for duplex uses on the' entire portion of Lot 8, triplexes on Lot 9 and more dense apartment units on Lot 10. The resulting densities would be 0 to 6 units (low- density residential) on Lot 8, 7 to 16 units (medium- density residential) on Lot 9 and 17+ units per acre (high density residential) on Lot 10. Under maxi- mum utilization this would provide for 30 units on Lot 8; 80 units on Lot 9 and 85 to 140 units on Lot 10 - -a total range of 195 to 250 units under this type of proposal. This assumes a limitation on the R -4 consistent with the comprehensive plan guidelines of 28 units per acre rather than the zoning code limitation of 43 units per acre. If R -4 under the zoning code was utilized for Lot 10, the upper range of units under this proposal would be 325 units. 4. All uses as proposed except that the single - family area would be retained as open space either by covenant to keep as a natural area or deeded in fee to the City as passive open space area with a potential site for a water reservoir facility. This alternative has been discussed as part of the comprehensive planning process and letters from the original property owners conveyed to the City indicating that this was a viable alternative to them. Subsequent conversations with various members of the City staff have indicated a strong concern at the City for pro- viding single - family sites. A review of the land use inventory document developed as part of the comprehensive planning process indicated that there have been only 12 single - family homes built in the area in the last 11 years up to 1976. The proposed addi- tional 10 single- family sites would match the single - family 88 development in Tukwila for the past 8;or 9 years. The area pro- posed t� be open space would be an extension of that 2.6 acres of open space along the ridge line. In that this area is ,highly suitable for low density development,.- either clustered duplex townhouses'or single - family, the proposal to provide single - family in this area would 1) provide additional. housing stockv.of a single - family nature in Tukwila, 2) provide a well- defined transi- tion zone from the existing R -1 -9.6 .to the north and northeast, and. 3) help to define what would occur on the property,- to the east, this appears to be the more logical alternative.. However, the alternative of. 'leaving this area an open space remains a viable one and should be determined as part of policy. decision by the Planning Commission and City Council. . Modify size and configuration of proposed use zones. A myriad of alternatives, .whereby minor modifications of the con- figurations of the proposed site plan could be undertaken. . The proponents' architect, site planners and others involved in the project have undertaken:numerous studies and discussions of alter - ' natives and-analysis of feasible and viable projects. These.dis- cussions have also been clarified and directed by- numerous discus- sions with the City staff. Minor modifications of the existing zoning proposals could be made as a part of the hearing process. .However, at this time.propbsed action appears to be responsive to the natural system, in response to the comprehensive plan map and policies and consistent with feasibility studies done for various developments on'the site.. 6. No action. This. alternative-would leave the site in -its undeveloped character awaiting utilization -of adjacent properties for residential -uses of various densities from RMH (high density apartments).. to de- tached single - family under R -1. Feasibility studies have shown that other than minor portions of the site being used for single - family it is highly unlikely that the property would be developed 89 in the short term absent any rezoninig action. The proponent does not have access to alternative sites and given a decision-not to approve this zoning application or some modification thereof, would withdraw fran the project. The previous fee owners,_ under contract purchase with the proponent; would retain the .property until zoning action could be clarified. Impacts of the Alternatives The impacts associated with each alternative would mainly relate to density, number of people, traffic, etc. In addition the amount of site _coverage, vegetation loss, runoff, topography change and other environmental factors impact would vary based on which alternative was considered. Alternative 1 - less open space would be- retained and more topography change for roads and side development probably would occur. Alternatives 2 & 3 - all impacts associated with .increased densities and site coverage would occur. The increase of 50 to 90% in densities would result in less open space, larger buildings, greater traffic flows, increased public services, etc. Alternative 4 - minor change in impacts due to ten less single family houses; more open space, increased, costs to City to maintain open space area, and loss .of tax base. Alternative 5 - minor changes associated with revised densities. Alternative 6 - no primary impacts; secondary impacts include land speculation, increased future building costs; loss of opportunities to improve utilities and circulation in the.area.. Circulation and Access Alternatives The alternative for potential access and circulation patterns are discussed in detail in Section IIIB, 3, page 64 in order to analyze in detail the City of Tukwila policy issue of circulation for the project site and its neighborhood. The benefits and impacts of three alterna- tives are enumerated in that section. Detailed review of that section is important to a discussion of Project Alternatives. 90 VI. THE RELATIONSHIP BEAWEEEN LOCAL SHORT -TERM USES OF MAN' ENVIRONMENT FT AND MAINTENANCE AND ENHANCEMENT OF LONG-TERM PRODUCTIVITY The site would be irretrievably committed to urban development, in contrast to alternative housing or open space uses. This is countered by the fact that the site is surrounded on 2 -1/2 sides by apartments, 1/2 side by single family and potential single family and 1 side by recreational uses and is in a municipality with utilities and access on most sides. Urban growth will continue on the Tukwila Hill and the development of the site can provide a new form of site planning and design for the area while preserving some open space and being comple- mentary to the goals and policies of the city. The commitment of this site will decrease the likelihood of pressure for more peripheral development on other open space. VII. IRREVERSIBLE OR IRRETREVABLE COMMITMENTS OF RESOURCES The alteration from wooded hillside to urban residential uses is for all practical purposes irreversible. The development of this site will consume energy throughout the building phase. The placement of streets, sewers and other utility lines and the preliminary develop- ment of residential units will involve the consumption of concrete, metals and wood resources which will be effectively lost for other use. The infilling of the urban fabric here will decrease use of resources for maintenance over time by being integrated into an exist- ing infrastructure near shopping and employment and by decreasing pressure for development on the peripheral areas of existing urban development. 91 APPENDICES A. Soils and Geology - Consultant Report B. Hydrology and Utilities - Consultant Report C. Calculations for Analysis of Impact D. Project Statistics E. Miscellaneous Resource Data and Maps F. Suggested Conditions G. References APPENDIX A SOILS AND GEOLOGY APPENDIX A BOX 126 HOE ;ART, k ASHINGTON 98025 "F+` fEL: AREA 206 - 682-6942 J Fi r s EHTori -- EARTH . SCIENEE ENGINEERING January 17, 1977 Robert W. ..Thorpe and Associates 3050 Island Crest Way Mercer Island, Washington 98040 Dear Mr. Thorpe: You asked me to make a cursory investigation of the soil conditions of a 15 -acre parcel in Tukwila. The site is under. consideration for waiver al_d rezone. It is roughly bounded by extension' of South 151st and South 153rd Streets and 59th and 62nd Avenues South. Elevation d.iffe72ential is about 60 or 70 ft. with the lowest terrain near the southeast corner and the highest. along part of the west property line. Surface drainage is good; although, because of human interference, water is ponde-a at nearby locations off • the property. At present, the entire tract is wooded and without improvements. As presently envisioned, . future improvements would be confined to the southeastern one -third or so of area. Those improvements would con-;• sist of 450 to 500 multiple-family units, although. the number does significantly affect. findings or con- clusions expressed herein. Prior to actual development, it will be necessary to explore the subsurface conditions in deta:Ll, either by test pits or borings.. Information in this letter Was developed from a ground reconnaissance and a review of relevant geologic publications for that area. Shallow soils across the area to be developed consist: of glacial till, a dense mixture of silt, sand, and r e 2 January 17, 1977 Robert W. Thorpe and Associates gravel. It is weathered in the upper two cr three feet. Except in the upper few feet which have been weakened by weather and root action, sliding is uncom- mon in till; and no signs of east sliding were noted. Exposures off the property to the south and southwest indicate that the till grades downward into a massive unit of relatively cleaner sand and gravel, also of glacial origin. small. outcropting . of ndesitic intrusive bedrock is exposed at the southeast property. corner. Soil irnmedi.- ately adjacent to the rock is of residual on :in. As a practical matter, only the glacial soil will be of much relevance to development. No surface indication; of adverse drainage conditions or seepage were noted. Except for possible localized horizons of perched saturation, true groundwater is no doubt well below the lowest property elevation. So far as the intended improvements are concerned, the .ost restrictive soil- related factors will be thel moisture sensitivity of the till and slope stability of any fills whicrl slight be placed. To minimize those potential problems, earthwork should be kept to a ..linimum, and it should ' be atte pted only during the dry season. By virtue of its cohesion and gravel content, till is not a highly erosive soil, although its impervious nature will cause greater runoff than from most other native soils.. Temporary sedimentation ponds.will be necessary during construction. Storm- water runoff will be regulated after construct ion; the effects of runoff will diminish over about a two -year -period while the new flora is establishing itself. Should City personnel or any other concerned parties have any questions about this matter, please encourage t_.:ein to Give me a call. Yours very truly,- ( uaflas N. Eaton APPENDIX B HYDROLOGY AND UTILITIES March 29, 1978 (Revised April 14, 1978) Mr. Robert W. Thorpe Robert W. Thorpe & Associates 815 Seattle Tower 3rd & University Seattle, WA Subject: 15 -acre Tukwila P.U.R.D. for Northward Development Co. Dear Mr. Thorpe: The following pages contain the requested technical infomation on the hydrology, water system and sewer system for the pro- posed Tukwila P.U.R.D. Hydrology Existing Conditions - Stormwater runoff generated by the site currently drains in three distinct directions. The northeast portion of the site drains into a well - defined drainage swale. This swale, which also receives drainage from the developed area to the north, broadens to form a shallow pond about one foot deep on the east boundary of the site. It then runs from north to south eventually empting into the I -405 storm drainage system. As well as conveying stormwater runoff the swale con- veys a small base flow component of approximately 0.1.cfs which acts as the source of the shallow pond. The south portion of the site drains into the currently undevel- oped property to the south. There are no distinctive drainage swales in this area. Runoff travels essentially as sheet flow until it is intercepted by Southcenter Boulevard and routed into the I -405 storm drainage system. A shallow depression which has a maximum depth of approximately 3 feet exists adjacent to the site's west boundary. Approximately 2 1/2 acres of the site as well as 1 1/2 acres west of the site (the only offsite area draining into the site) drain into this depression. This drainage is apparently the source of the stand- ing water (which is probably seasonally intermittent) at the depression. Proposed Site Drainage - The existing drainage patterns at the site will be basically retained. Stormwater runoff from the northeast portion of the site (which is proposed for the least intensive development) will pass through oil -water separator 846 - 108TH AVENUE N.E. • BELLEVUE, WASHINGTON 98004 • PHONE (206) 454 -0711 Page Two Mr. Robert Thorpe catch basins and then be conveyed to the existing drainage swale at the•eastboundary. As a result peak flow rates will increase in the swale.-.. However at. points A and B as shown on the Existing Drainage map, :the peak 10 -year return interval flows should increase : -by,only 30 %.and 20 %, respectively (from 7.7 cfs to 1(.1 cfs at :A and from 9.9 cfs to 12.1 cfs at B) . Due to the relatively. steep channel.slopes the existing capa- city of the downstream system.should.be adequate to accommodate this flow rate increase. • Because of the more intensive proposed development of the south portion of the site, stormwater detention facilities will be provided to limit the 10 -year peak discharge to.the south to approximately the existing 1.2 cfs 10 -year peak flow rate. Discharge from these facilities will probably be made into a storm sewer line which should be built at 62nd Avenue South in conjunction with improvement of that street to facilitate this and neighboring developments. Such a storm sewer would then discharge into the I -405 system at Southcenter Boulevard. The depression along the west boundary will probably be devel- oped as a shallow pond for use as an amenity to the project. However runoff from a portion of the area currently tributary to this depression may be routed into the detention facilities at the south portion of the site. Water System City of Tukwila watermains currently exist at or near all four corners of the site. The supply source of all of these mains is a 16 -inch diameter City of Seattle watermain. Therefore the esitmated average daily residential consumption for the site of 74,625 gallons (based upon 199 units, 2.5 occupants per unit, and 150 gallons per day per occupant) is not expected to adversely affect water supply to other City of Tukwila users. Looping of some or all of the existing systems may be required for provision of adequate fire flows to the upper elevations of the site. Such looping would also benefit nearby properties by increasing available fire flows in the existing mains. Sanitary Sewer System Sanitary sewage generated by the proposed development will drain into two different sewer mains. The main at the intersection of 62nd Avenue South and South 151st Street will receive sewage from the proposed single family and duplex areas of the site. The average daily sewage discharge from this area is estimated to be 7000 gallons (based upon 28 units, 2.5 occupants per unit, and 100 gallons per day per occupant). Page Three Mr. Robert Thorpe Sewage from the four -plex and condominium areas will gravity to the south. This will necessitate extension of the existing sewer main on 62nd Avenue South up to the Southeast corner of the project. Average daily discharge from this portion of the development is estimated to be 42,750 gallons (based upon 171 units, 2.5 occupants per unit, and 100 gallorts per day per occupant). This additional sewage'is not expected to create sewage flow capacity.porblems in existing downstream mains. Sincerely, TRIAD ASSOCIATES, INC. David L. Halinen, Project Manager DLH:cg Trip Generation Proposed Units APPENDIX C Calculations for Analysis of Impact ADT's/Unitl Average Daily Traffic 10 single family houses :10 , 100 18 duplex townhouse condos 6 108 32 fourplexes 6 192 139 condominiums 6 834 1,234 Population/Housing 2 Single 5+ units Total family Duplex Triplex 4 -Plex Bldg. 1977 Census . 1965. 574 22 3 48 1038 1978 Census 1693 578 22 3 52 1038 Added by Project . (Est. 1982) 199 10 18 32 139 As % of 1978. .11.8 1.7 81.8 61.5 .. 13.4 Est. population /unit (2.5) 3.0 3.0 2.2 2,.2 Est. population added. 498* 30 54 70 306 *High Estimate Projected Population Units 189 condominiums 2.2 416 10 single family ' 3.0 30 446 (say 450) Probable Population Estimate 498 (say 500) High Estimate 400 (say 400) Low Estimate 1Institute'of Transportation Engineers, 1976. 2City of Tukwila census data. Projected Student Population - School Ages. 60 -100 students 30 -50 50% elementary 30 -50 50% junior /senior high Water Usage Estimated to be approximately 150 gallons per day per resident.3 448 to 498 persons x 150 gpd = 67,200 to 74,700 Sewage Flow Estimated to be approximately 100 gallons per day per resident. Projected Resident Population: 448 to 498 persons x 100 gpd = 44,800 to 49,800 gpd Residential Electrical Requirements Estimated on the basis of approximately 2,000 kwh per unit per month for all - electric units. (Puget Power — phone conversation). Proposed: 199 units x 2,000 kwh /unit /month = 398,000 kwh /month Residential Communications Requirements Estimated on the ebasis of 1.25 cable pairs per multifamily unit and 1.75 per single family unit (Pacific Northwest Bell, March, 1978). Proposed: 189 units x 1.25 cable pairs /unit = 236 cable pairs 10 units x 1.75 cable pairs /unit = 18 cable pairs Total 254 3Sources: Survey by R. W. Thorpe & Associates and engineering firms (February 1978), Triad Associates. APPENDIX D PROJECT STATISTICS LOCATION: CITY OF TUKWILA CODES: TUKWILA ZONING ORDINANCE AND UBC 1973 EDITION SEISMIC ZONE: III FIRE ZONE: III OCCUPANCY: H- MULTI - FAMILY. CONSTRUCTION TYPE: V -N, & V -ONE HOUR IN R -4 ZONE EXISTING ZONING: R -1 PROPOSED ZONING: ZONE R -4 268,615 S.F. R -3 137,308 S.F. R -2 97,101 S.F. R -1 (9,600) 138,753'S.F. TOTAL SITE AREA 641,777 S.F. AREA SITE COVERAGE: MULTI - FAMILY SINGLE FAMILY TOTAL PAVING COVERAGE: ROADS, DRIVEWAYS, & PARKING AREAS WALKS & PATHS POOL & PATIO TENNIS COURT OPEN AREAS i ACREAGE D.U. /ACRE 6.16 22.70 3.15 10.20 2.23 8.07 3.19 3.14 14.73 ACRES 99,025 S.F. 15,000 S.F. (APPRX.) 169,000 S.F. 14,720 S.F. 2,700 S.F. 7,200 S.F. 193,620 S.F. 334,132 S.F. 15.5% 2.3% 17.8% 30.0% 52.2% GREENBELT AREAS 111,400 S.F. 2.56 ACRES (NATURAL VEGETATION RETENTION) UNIT STATISTICS ZONE UNIT TYPES SQ. FOOTAGE NUMBER R -1 SINGLE FAMILY UNDETERMINED 10 R -2 A DUPLEX TOWNHOUSES 1,502 S.F. 18 R -3 B 4 -PLEX TOWNHOUSES 1,231 S.F. 32 R -4 B TOWNHOUSES 1,231 S.F. 6 R -4 C 2 -BR. FLAT 1,077 S.F. 48 R -4 D 2 -BR. FLAT 1,074 S.F. 28 R -4 E 2 -BR. FLAT 995 S.F. 57 199 1 i BUILDING AREA CALCULATIONS BUILDING 1: 4 B UNITS @ 1,231 = 4,924 15 E UNITS @ 995 = •14,925 8 D UNITS @ 1,074 = 8,592 CORRIDORS & STAIRS = 3,036 MECH. & STORAGE • = 420 TOTAL 31,897 S.F. BUILDING 2: 2 B UNITS @ 1,231 _ 2,462 15 E UNITS @ 995 = 14,925 8 D UNITS @ 1,074 = 8,592 CORRIDORS & STAIRS = 3,036 MECH. & STORAGE = 1,380 TOTAL 30,395 S.F. BUILDING 3: (UNDER BLDG. PARKING EXCLUDED) 12 D UNITS @ 1,074 = 12,888 27 E UNITS @ 995 = 26,865 CORRIDORS & STAIRS = 6,206 MECH. & STORAGE = 3,600 TOTAL 49,559 S.F. BUILDING 4: .18 C UNITS @ 1,077 19,386 S.F. BUILDING 5: 12 C UNITS @1,077 12,924 S.F. BUILDING 6: • 4 B UNITS @ 1,231 4,924 S.F. BUILDING 7: RECREATION BUILDING 1,800 S.F. BUILDINGS 8 THRU 12: 4 B.UNITS @ 1,231 S.F. = 4,924 5 X 4,924 = TOTAL 24,620 S.F. BUILDING 13: 12 C UNITS @ 1,077 12,924 S.F. BUILDING 14: 6 C UNITS @ 1,077 6,462 S.F. BUILDINGS 15 & 16: 4 B UNITS @ 1,231 S.F. = 4,924 S.F. 2 X 4,924 = TOTAL 9,848 S.F. BUILDINGS 17 THRU 25: 2 A UNITS @ 1,502 S.F. = 3,004 S.F. 9 X 3,004 = TOTAL 27,036 S.F. TOTAL GROSS PROPOSED BUILDING AREA (NOT INCLUDING SINGLE FAMILY) 231,775 S.F. PARKING SPACES ZONE SPACES /UNIT # UNITS SPACES REQD. PROVIDED R -1 2 /D.U. X 10 = 20 20* R -2 2 /D.U. X 18 = 36 40 R -3 2 /D.U. X 32 = 64 64 R -4 1.5 /D.U. X 139 = 209 209 329 333 ** *GUEST PARKING PROVIDED ON STREET. * *227 OF THESE SPACES ARE COVERED. APPENDIX E MISCELLANEOUS RESOURCE ;: DATA AND MAPS APPENDIX E ICJ 6 • LEI >• TIM 11•111G[ • [•ST MOM 5 [AST CITY OF TUKWILA ZONING LEGEND R•A RESIDENTIAL • AGRICULTURAL 6.1.7.2 1 FAMILY RESIDENCE ' R•19.6 1 FAMILY RESIDENCE 6.1.12.0 1 FAMILY RESIDENCE 6.2.8.4 2 FAMILY RESIDENCE 6.3 3FAMLYRESIDENCE R•3.60 3a1 FAMILY RESIDENCE 1•0 LOM APARTMENTS RMM MOl[ RESIDENCE NIGN DENS. PF PDILIC FACILITY C 1 NEICIIIWIMOOD RETAIL C2 LOCAL RETAIL CPR PLAWO BUS. CE!ITEI REGIONAL CM INDUSTRIAL PARK M 1 LICIT INDUSTRY M 2 MEAYE MIDIKTRY II N .Y••• ert■ 1.••, • /1:1 ICA-ALL 1 ON GN NN 1 �n . FIGURE 16 ACCESS & CIRCULATION ALTERNATIVES Ilia II IMIMI M1 Primary. Access Alternatives \-1 OO lJ ILS r. 1 I I It', I 4. I :� !I 1 I I - 330 5 ,336 L 44.• 11111ewa r■ ruR wLj .�cm. sc'jr"v 149 I4923 n„ 0 \ ;44t3 \ S i•4C /4917-P ST'., SO ■ • • ,r y00 22 Li r,1 11 1 GI S /5 /ST ; ST I :� ��; I L's 1 % ... Nt I /5?•///D ' v,1c_ S7:; 1 'A I .t - - -S 1 6 1: . ♦I , 1 , V A C. 37 • 1 19 JOO e. 15 e;;;;-„ ryce,, IN0 121- - ./1 15 GOLCSM!TH APPENDIX F PARK PLACE REZONE SUGGESTED CONDITIONS FOR REVIEW OF REZONE APPLICATION Lots 8, 9 & 10 - Interurban Addition 1. That densities be limited to those shown in Table 3. of the Draft Environmental Impact Statement with the total number of units not to exceed 199. 2. That the site plan for 14.7 acre parcel maintain over 40% of the area ' in open space, landscaping and natural areas. 3. That buffer zones of natural vegetation of a minimum of 40. feet be preserved on the north and east boundaries of the property. 4. That the applicant participate in the development of utilities and improved area access to serve the site. 5. That circulation for emergency vehicles be provided through the site if feasible. 6. That groupings of major trees, drainage swales and other natural features be inventoried.and incorporated in the site plans'where feasible. 7. That the rezone be based on a condition that the Planning Commission review specific site, elevation, floor and landscape plans prior to site development and issuance of building permits. 8. That appropriate mitigating measures of the Final Environmental Impact Statement be accepted as conditions of zoning approval. 9. That all conditions set forth and agreements between the City of Tukwila and the applicants be attached to the fee title and be binding on all heirs, successors or assigns. APPENDIX G REFERENCES 1. City of Tukwila. Data Inventory: Tukwila Planning Area. 1975. 2. City of Tukwila. Proposed Comprehensive Land Use Policy Plan. 1977. 3. City of Tukwila. Park and Open Space Program 1976 -1981. (Ord. 964), March 1976. 4. City of Tukwila. Tukwila Comprehensive Zoning Ordinance (Ord. 251 as amended). 5. City of Tukwila. February 1977. 6. City of Tukwila. Department. Final EIS Comprehensive Land Use Policy Plan. Preliminary 1978 Census Data - Planning 7. City of Tukwila - 1978 Budget. 8. Synder, Dale. Soil Survey of King County Area, Washington (unpublished) 9. USDA, Soil Survey of King County. 10. Numerous conversations with resource persons in the City, utility companies, the School District, etc. Available from field notes. Comments Received on DEIS Written Comments from Public Agencies Responses to Above Comments from Two Public Meetings Responses to Above Communications received after Deadline Action /Responses to Above 107 Page 108 118 120 120 116 118 CITY of TUKWILA OFFICE of COMMUNITY DEVELOPMENT 23 May 1978 Mr. Robert W. Thorpe R. W. Thorpe and Associates 815 Seattle Tower Third and University Seattle, Washington 98101 RE: Comments, Park Place DEIS Dear Mr. Thorpe: Please find enclosed a copy of all written comments received to date in response to the Draft EIS distributed for the Park Place proposal in Tukwila. Inasmuch as the public hearing before the Planning Commission will be conducted on 25 May 1978, it is suggested that your response document (as outlined in WAC 197 -10 -580 (2)) to the enclosed comments as well as any comments received at the upcoming public hearing be prepared subse- quent to the Commission's hearing. When completed to the satisfaction of this office, the response document will be circulated as the Final EIS in . accordance with WAC 197 -10 -600. Should you have any questions or desire to discuss the responses, please call. Sincer Ga y Crut hfield Assistan Planner GC /ch Enclosures: ) Telephone message, 4/20, Tukwila Fire Department 2) Letter, 4/27, EPA 3) Memo, 5/1, Tukwila Recreation Department 4) Memo, 5/8, Tukwila Public Works Department Letter, 5/12, DOE 4� ■ SAG (G. tr'Dam(w.o.) 6230 Southcencer Boulevard ■ Tukwila, Washington 98188 ■ (206) 242 -2177 pv� STATE OF WASHINGTON Dixy Lee Ray Governor DEPARTMENT OF ECOLOGY Olympia, Washington 98504 206/753.2800 May 12, 1978 Mr. Gary Crutchfield City of Tukwila Planning Division 6230 Southcenter Boulevard Tukwila, WA 98188 Dear Mr. Crutchfield: Thank you for the opportunity to review the Draft Environmental Impact Statement for Park Place Rezone. We have no substantive comments to offer on this project. If I can be of further service, please call me at 753 -6892. Sincerely, Carol L. Fleskes Environmental Review Section CLF:bjw s %tee star U.S. ENVIRONMENTAL PROTECTION . AGENCY J� REGION X s. 2'A 7- 0 1200 SIXTH AVENUE y 10V w O O Q �yl-4 PROSCG� REPLY TO ATTN OF: M/S 623 APR 27 1978 SEATTLE, WASHINGTON 98101 Mr. Gary Crutchfield City of Tukwila Planning Division 6230 Southcenter Boulevard Tukwila, Washington 98188 Dear Mr. Crutchfield: ECE1VE APR 2 8'1978 CITY OF TUK ILA We have completed our review of your draft environmental impact statement for the Park Place Rezone in Tukwila, Washington. We would like to submit the following comments for your. consideration The draft statement's discussion of the project's impact upon air quality and surface and ground water quality is adequate, however we feel the discussion of the project's noise impact should be expanded. The draft EIS mentions, on page 15, that "heavily insulated buildings, double -pane windows, landscaping, fences, and earth berms" will be used to attenuate traffic noise, however the EIS presents no "as measured" noise levels at the project site. Building designers must know the existing exterior noise environment before they can design structures which will provide a livable interior noise level, there- fore we suggest that actual noise levels be measured and presented in the final EIS. The actual noise levels should be measured during hours of peak traffic. The final EIS should include a discussion defining those measures which will be implemented to reduce construction noise. The following list of construction noise abatement measures is suggested: 1. the use and maintenance of properly operating mufflers and quieting devices 2. the use of quietest available machinery and equipment 3. the use of electric equipment in preference to gas, diesel or pneumatic machinery 1/49 z . • 2 4. locating construction equipment as far from nearby noise sensitive properties as possible 5. shutting off idling equipment 6. limitation of construction hours to coincide with the normal workday period, e.g. 8:00 a.m. to 6:00 p.m. 7. scheduling the noisiest operations near the middle of the day, and notifying nearby residents whenever extremely noisy work will be occurring 8. the use of permanent or portable barriers around point noise sources. We appreciate the opportunity to review this draft environmental impact statement. Please do not hesitate to contact Dennis Ossenkop, of my staff, should you have questions or desire further information regarding our comments. He can be reached at (206) 442 -1595. Sincerely, • 4(1_4 n / Gt 6, cV uL.(- C? Alexandra B. Smith, Chief Environmental Evaluation Branch /1/ CITY of TUKWILA PARKS Et RECREATKM EPARTMERIT 6230 Southcenter Blvd., Tukwila, Wash. 98188 Telephone: 242 -2177 1 May 1978 MEMORANDUM .TO: Gary Crutchfield ,,,/ FROM: Don Williams ��� -/�' SUBJECT: Comment on Park Place Development After a review of the Park Place Rezone E.I.S. I have some concerns and have listed such below. You will note that my main concern is with regards to the foottrail that exists along the 62nd Avenue South Right -of -way. Some of my questions are minor and I believe some are of major concern. I assume you will present my concerns at the proper time, if not please advise me on what I can do. 1. The map on page 24 indicates a partial road connecting onto South 151st Street and to 62nd Avenue. Does this eliminate the north and south ends of the existing trail? 2. Same map on page 24 shows several arrows indicating trails in the project connecting into our trail. The statement on page 25, 6th line down states, "Existing trails in the area are linked through the site ". Does this mean they plan to directly connect into our trail? 3. With all of the regrading, etc., that they plan to do will the changes in elevations that they make cause problems with the stability of our right -of -way and the trail? Will differences in existing trail elevations and the new trails create a physical barrier to most users? 4. The existing trail has a 16' long bridge that allows hill drainage to continue its natural path, that is running east under the bridge and then south. Will any grading cause a change in the flow loca- tion of the current drainage basin? If so, will the bridge need to be relocated and at whose cost? Gary Crutchfield Memorandum Page 2 1 May 1978 5. If any damage is done to the path during construction who will pay for repairs? If any of the trail is eliminated because of the project will the City be compensated? 6. Will construction over the three year period be done in such a manner that t1.7 . n.3_:1 ./ : Qa l o i "f3 i C •:3 3 fp / Date: May 8, 1978 To: Terry From: Dick Subject: Park Place .NEMORANDUM Rezone - Preliminary DEIS I have the following comment to offer: Traffic & Transportation, page 14: The mitigating measures outlined in this section do not address the additional impacts to the property east of this site. The roadway system as proposed does not allow for any through movement of traffic from So. 151st to So. 153rd and eliminates the possibility of So. 152nd Street connecting to 62nd Ave. So. The approval of the access plan as indicated would impact the property west of this site in such a way that all developments on the west property will forever be restricted to using So. 152nd down to Macadam Road. Emergency vehicles and maintenance vehicles, rather than having two open usable routes to any area on this hill, will be restricted to one usable access point. In conclusion, I think that streets should be developed to allow for free-flowing access and egress to any area on the hill from at least two difference and publicly - owned roads. These road sections should include all required utilities. RKW /dp cc: Kjell Stoknes Gary Crutchfield 4 TO aff DATE Vii-fiLE 'YOU. IMAIMFROM TIME gZLL (ta,J) TELEPHONE NO. OR OPERATOR OF 1 EXTENSION Telephoned D Please Call Back D Will Call Again Wants To See You See OperE / MESSAGE 3 poitAiiie4 A& D cuti, -10* SIGNED CASCADE• Li .C2338 1.01m,tumy5, 6.6 Municipality of Metropolitan Seattle Exchange Bldg. • 821 Second Ave., Seattle,Washington 98104 May 26, 1978 Mr. Gary Crutchfield Planning Division City of Tukwila. 6230 Southcenter Boulevard Tukwila, Washington 98188 Dear Mr. Crutchfield: ECEIVE MAY 3 0 1978 CITY OF TUKWILA Draft Environmental Impact Statement Park Place Rezone Metro staff has reviewed . this document, and we do not anti- cipate adverse impacts to our wastewater facilities or public transportation system as a result of this rezone. Metro is now working with local jurisdictions to implement the recommendations of the 208 Areawide Water Quality Plan and evaluating the implementation of policy recommendations included in Environmental Management for the Metropolitan Area. While we believe the Draft EIS did a commendable job in discussing the water quality issues, it would be helpful if the following items were clarified. The Draft EIS makes reference to mitigating measures which could be implemented. It is difficult for us to understand the magnitude of the project's impacts unless it is made clear which measures will actually be undertaken. Roof and parking lot detention facilities are discussed in the summary on page 15 of the Draft EIS but are not discussed elsewhere in the document. The Final EIS should specify the commitment to detention facilities and state who will be responsible for ongoing maintenance of the drainage facilities. Page 48 indicates that stormwater detention facilities will be provided in the southern portion of the site. It would be helpful if the Final EIS specified the type of detention facilities to be used - -pond, underground pipe, or rooftop. Page 49 states that attempts will be made to facilitate absorp- tion of the stormwater into the ground. This would reduce surface runoff and have beneficial effects on surface water Mr. Gary Crutchfield May 26, 1978 Page Two quality and quantity. Care should be taken so that excessive quantities of water are not introduced into the ground in steep slope areas since concentrations of groundwater in certain situations can induce landslides and extensive erosion, thereby impacting stormwater quality. Since peak flows will be detained on site, according to a statement on page 70, they should be controlled to the level which existed before construction in order to preserve water quality. The sentence on page 48 appears to be inconsistent with this, in that it states that peak flows in that area will increase by 20 to 30 percent. Thank you for this opportunity to review and comment on this document. Very truly yours, Peter S. Machno, Manager Environmental Planning Division PSM:ksa RESPONSES.T0 WRITTEN COMMENTS 1. Department of Ecology (5/12/78) Thank you for your review and indication of no comment. 2. Environmental Protection Agency (4/27/78) Thank you for your comments on noise impacts. Noise levels have been measured 18 months ago and will be remeasured now for building design and insulation details. These noise measurements will be made during A.M. and P.M. peak hours. The noise mitigation measures have been incorporated. Thank you for noting the oversight. 3. Tukwila Parks and Recreation Department (5/1/78) The writers of the EIS discussed the ten questions with Mr. Don Williams and resolved most concerns as follows. 1. North and south ends to be moved, developer will provide a good or better end points of trail. 2. Yes - but are just existing foot paths on existing side. 3. No 4. No change in drainage area or bridge. That area is open space and will be undisturbed. 5. No trail elimination - see also #I1. 6. Ibid 7. Paths left open. Vegetation retained and supplemented with landscaping. 8. One or two play areas are contemplated in project site. Exact loca- tion to be determined during construction. 9. Comment noted. See school sections of FEIS. 10. Area -wide problem; this project will likely in itself not create the demand for a light. Thank you for your comments and opportunity to discuss them for the benefit of the project and the City. 4. Tukwila Public Works Department (5/8/78) Paragraph 1 - Please see additional sections III B3 and V - Alternatives which discuss these impacts. Paragraph 2 - See Sections sited above. Emergency vehicles have been provided access from three points around the property (west from 152nd; 118 south from 62nd and north from 62nd at 151st). Maintenance vehicles can also have access designed for them. Paragraph 3 - Road areas will include all utilities to loop existing dead end services and improve these systems. The issue of circulation is a policy issue that was discussed in detail by the project proponents and the Planning Commission. The Planning Commission unanimously recommended to the City Council that only emergency access be provided through the site. 5. Tukwila Fire Chief (4/20/78) Phone Message: Thank you for your response. The research method of determining the adequacy of fire flows to any one site in Tukwila would be to model the entire City water reservoir and distribution system as has been done in Renton. It is our understanding from talking to their consultant, CH2M Hill, that a similar project for Tukwila's residential areas would cost $24,000 - $30,000 and require 9 to 12 months to complete The project sponsor would be happy to participate on a percentage of site area to the entire City, but time delays would cause them to abandon the project. As mitigating measures the project sponsors suggest: a. Complete linking of all dead -end facilities to improve fire flows. b. Discussion of requirements for sprinkling hallways and entrances of units to offset demonstrated low fire flows prior to occupancy. c. Fire access to all structures. d. Separation of 4, 2 and 1 unit structures to reduce fire problems. 6. Metro (5 /26 /78)(Mailed after Deadline) Paragraph 3 - See Conditions of Approval - All mitigating measures can be required by responsible official. Paragraph 4 - Maintenance of drainage retention facilities will be by homeowners and provided for in covenants and 'deeds for the condominiums. Changes made in text. Paragraph 4 - Page 48 - Will use underground and vault. (changes made to text). Paragraph 6 - Those areas can handle limited runoff from 10 single family lots and 2.23 acres containing 18. duplex units. No retention proposed in this area - See Figure 11. Thank you for your comments; we hope we have responded in the limited time available before printing the FEIS. 119 • • COMMENTS AT PUBLIC HEARINGS April 27 and May 25, 1978 Mr. & Mrs. Donald E. Sipe ,14961 52nd Ave. South Both individuals who live adjacent to the project site at its corner spoke at both hearings. There comments were generally 1. They were in favor of the project as proposed; they agreed use in the northeast corner was a good use and open space them off from the condominiums. northeast as follows: single family areas screened 2. They responded to Commissioners questions indicating they were opposed to through circulation to the northeast corner and could see no reason for through circulation to the apartment areas along 152nd. 3. They supported the proposed project phasing and good faith shown by the detailed designs and limited densities. Thank you for your input. The only public comments received at either hearing. 120 DRAFT ENVIRCUME TrAL IMPACT STATEMENT FOR PARK PLACE REZONE CITY OF TUKWILA In Compliance With: 'The State Environmental Policy Act of 1971 Chapter 43.21c, Revised Code of Washington SEPA Guidelines, Effective January 16, 1976 Chapter 197 -10, Washington Administrative Code Date of Issue: April 17, 1978 Cost Per Copy: $4.50 Responses Due: May 22, 1978 INTRODUCTION Project Sponsor: Dick Gilroy Northward Development Company 1115 108th Avenue N.E. Bellevue, Washington 98004 Proposed Action: The sponsor is requesting that the City of Tukwila• approve a contract rezone and general site plans in a Planned Unit Development format for a 15 -acre parcel on the south face of. Tukwila Hill to pro- vide for 184 condominium units and 10 single - family building lots. Rezone request of the 15 -acre parcel will be broken into R -4, R -3, R -2 and R -1 9600 single - family parcels with major open- space areas defin- ing various residential densities. Project Location: On the south face of Tukwila Hill above Southcenter.Boulevard and Southcenter shopping area. The project will be north and slightly west of the new Tukwila City Hall. The site is located between the westerly extension. of. Suth 151st Street and'the easterly extension of South 153rd Street between 59th Avenue South and 62nd Avenue South. See Figures 1 and 3. Lead Agency: The City of Tukwila Responsible Official: Kjell Stoknes, Director Office of Community Development Contact Person: Gary Crutchfield, Tukwila Planning Department, 244- 6290,. 1 Principal Contributors /Location of Background Material: Environmental Analysis and Document Preparation: R. W. Thorpe and Associates 815 Seattle Tower - Third and University Seattle, Washington 98101 623 -2935 Architecture and Site Planning: Len Milbrandt McClarty, Johnson, Associates, P.S. Inc. 16301 N..E. 8th . Bellevue, Washington 98008 747 -4050 Geology and Soils: James Eaton, P.E. Eaton Engineers P.O. Box 126 Hobart, Washington Engineering, Utilities, Hydrology, and Surveying: Dave Halinen,.P.E: Triad Associates 846 .108th N.E. Bellevue, Washington 98004 454 -0711 Applications, Permits and Licenses Required Rezone approval, site plan approval, subdivision for single family units clearing and grading permits, building permits, utility permits, certificates of occupancy. Location of EIS Background Data: .Tukwila Planning Department, Tukwila City Hall (See Appendix;G.- References . R. W. Thorpe and Associates, Seattle Date of Issue: April 17, 1978 Cost Per Copy: $4.50 Date Comments Due on Draft EIS: May.22, 1978 2 RECIPIENTS OF THE DRAFT ENVIRONMENTAL IMPACT STATEMENT Federal: Walter Jaspers U.S. Environmental Protection Region X 1200 6th Avenue Seattle, Washington 98101 State: Agency Office of the Governor Legislative Building Olympia, Washington 98504 Department of,3Ecology c/o Dennis Lundblad, Head Environmental Review Olympia, Washington 98504 Regional: Puget Sound Council of Governments Briam Beam, Environmental Planning Div. Grand Central on the Park Seattle, Washington 98104 Puget Sound Air Pollution Control Agency A.R. Dammkoehler, Air Pollution Control Officer 410 West Harrison Street P.O. Box 9863 Seattle, Washington 98109 Municipality of Metropolitan Seattle Peter Machno, Manager Environmental Planning 821 2nd Avenue Seattle, Washington 98104 King County Land Use Management Division Edward B. Sand W -217 King County Courthouse Seattle, Washington 98104 Kent Planning Agency James P. Harris, Planning Director P.O. Box 310, City Hall Kent, Washington 98031 Renton Planning Department Gordon Ericksen, Planning Director 200 Mill Avenue South Renton, Washington 98055 Dr. Richard Wade Seattle -King County Health Department 903 Public Safety Building Seattle, Washington 98104 John J. Fotheringham South Central School District #406 4640 South 144th Seattle, Washington 98168 King County Public Library (3) 4205 South 142nd Seattle, Washington 98168 City of Tukwila: Mayor - Honorable Edward Bauch City Clerk (3) Fire Department Police Department' Public Works Department Parks and Recreation Department City. Attorney SEPA Public Information Center Planning Commission Newspapers: Record Chronicle Seattle Times:.- South End Addition Seattle Post Intelligencer 4 FIGURES Number Title Page. 1 Vicinity Map 7 2 Site Plan and Proposed Zoning 8 3a Neighborhood Zoning and Development Patterns - Existing22 .3b Neighborhood Zoning and Development Patterns - Proposed23 4 Site Plan - Trails, Open Spaces, Circulation 24 5 Comprehensive Land Use Plan 27 6 Topography 36 7 Grading Plan • 37 8 Existing Conditions 38 9 -1 Geologic Characteristics 39 9 -2 Soil Groups: Description and Characteristics 40 10 Existing Drainage 46 11 Drainage Plan 47 12 Water System. 71 13 Sanitary Sewer System 71a 14 Site Sections 87 15 Elevations 88 TABLES Number Title 1 Proposed Zoning Areas and Densities 56 2 Population and Housing 59 5 A. The Proposed Action Project sponsors propose a rezone (with conditions) of the 14.7 - acre parcel which consists of lots 8, 9 and 10, Interurban Addi- tion to Seattle and site plan approval to allow for rezoning of currently R -1 and R -3 designated properties (see Figure 3) to R -4 (Low density multi - family) , R-3 (3 &4 •family units) , R -2 (2 family) and R -1 9600 (single - family), as shown in Figure 2, subject to conditions and site plan approval as described below. The northeasterly 3.19 acres of the property is proposed for R -1 9600 zoning to be developed with 10 single - family detached sites, averaging 10,000+ square feet per lot. The northwesterly corner, containing 2.23 acres is proposed to be R -2 for two -unit townhouse structures are would contain 18 units. An open -space area con - taining 2.56 acres will be provided; the R -1, R -2, R-3 and R -4 areas. The R -3 property contains 3.15 acres of property and fol- lows the general ridge line, as shown in Figure 6, Tbpography;Map. This property is proposed for 32 units, in 8 buildings containing four units each. The balance of the property on the south and southwest, abutting existing R -4 and R -3 zoned property, would be developed under R -4 zoning to contain 139 units on 6.16 acres of ground. This area would contain a minimum of 209 parking stalls in order to fulfill the 1.5 parking spaces per dwelling unit requirement. The total proposal, then, would have 189 common -wall units and 10 detached single - family hones. All units are planned to be condo- minium, owner occupied units. The open -space areas that are in large tracts would be protected with restrictive covenants and a no -build zone imposed on the site plan approval. Access to the project would be primarily from the southeast corner via 62nd Avenue South (north of the access point to the new Tukwila City Hall), where 62nd joins South 153rd Street. Access for the 6 1 E ST •tl: , "1.• • 8000 0 , fi. ,'';.1�, :1 Bayer 1 1 3,1 1 L• ,r :. KENNYO ►ALE I /1 ' \1 COIE1t4N PUINI W11-1.1-ft :1- 1:1 ...•.. I. 11 Ste s:■% Mkt\', :.; . �✓• SOUTH POINT ,RAINIER BEACH '•1r tii'; Pea WWII,. ST l •11••11L ►.; i ', c0 II) 101 TIE .ERLY PARK 1 1� BRYN MAWR NAZEL•�,T Y LLEY St ,f•?' 30 S► SeohU1S1.7ii • o►k 1'• • _: • ��K s • Se ► �SOUTHLANO -- CHELSEA PARK _46 BU • 100 r4- �• 300„' RIYERT Ail"; r.t ..t' 'w• 'coy �t FI.VEL ;SUKNYDALE! N HTS Ihr X0• 131 SIOJ • • RENT\ON' Y HTS • • • • SE 164 cT 71■•a..►.1 v \ SE 168 ST 1? ,E .17 17 %cJ) 51 , ,1_St 7rt st 114 •:• • • let, It. op 1.1,rw +I,► OrUIia1gp l• a RT NORTH II \ \1 t . r•;....• • fs 1. AnglefLoke I. • ••••••4 49 . 1 • 1 f -) .7 1 • [1 . • MM •1•:+• ,n•si aw Una '0 # �/ GN as i 5 O•!11 -••• -1011 NV'ld 3118 • moo OMIUN1 01310E /0 1001 --1 OVIA 100101 '-- I eke ♦ /,0 IC � e► a". N 0 1-4 00 single - family units would be east via South 151st, or north via 62nd Avenue or South by and 59th Avenue. The entire development would be phased over a two or three year period, building 50 to 75 units per year as the market dictates. Phasing would proceed from the south to the north under present plans. B. Potential Direct and Indirect Environmental Impacts 1. Elements of the Physical Environment Soils, Geology and Topography a. Localized erosion as areas are subjected to clearing and grading. b. Some cut and fill areas as portrayed in Figure 7, required for construction of proposed structures, roads and access points, with a net surplus of 4,000 cubic yards to be used in berms or removed from the site (probable to a fill site in developing industrial /commercial areas). c. Compaction, alteration and over- covering of soils for construction facilities. d. Alteration of topography due to the required cut and fill. e. Removal of about 6,000 cubic yards of bedrock from the southeast corner of the site, to be used elsewhere on the site. Air Quality a. Long -term increased emissions from site - generated vehicu- lar traffic, fireplace use and heating. b. Short -term construction- related increase in dust emissions from construction equipment, open burning and blasting. Water Resources a. Some alteration of runoff quantity due to increased area of impervious surfaces, altering the flow characteristics in a year -round stream. b. Increased turbidity, petroleum product residues, nutrients and slightly elevated temperature in runoff. c. Potential diversionof groundwater movement. 9 Flora/Fauna a. Elimination of some trees and understory vegetation „ par - ticularly from the south and westerly portions of the site. b. Removal of vegetation will result in reduction of wildlife habitat. c. Adverse impacts on downstream fisheries may result from an increase in pollutants in the drainage basin. Noise a. Increase in on -site noise levels during construction, drawn out by proposed construction phasing. Some blasting will occur. b. Some increased traffic noise from site - generated volumes. c. Exposure of new residents of the site to highway noise currently in excess of recommended levels. Light and Glare a. Addition of artificial light sources in the project area. b. Increased quantity of traffic movements at night. Land Use a. Commitment of the 15 -acre site to urban residential use. b. Increase in the intensity of land use by the provision of 139 units at 5 or more per building. 32 four -plex units, 18 duplex townhouse units and 10 single - family units for a total of 199 units. c. Compatible with or more site sensitive than apartment developments on the west and east and south of the subject property; provides transition zones from existing level- . oped zones. d. Generally consistent with adopted comprehensive plan for the City. 10 Natural Resources. a. Removal of 50 per cent of vegetation and trees. b. Commitment of, undeveloped land to urban uses. c. Consumption of energy and natural resources on site. 2. Elements of the Social Environment Population Increase in the population of the area by 450 to 500 persons by 1981. Housing a. An increase in the number. and variety of housing in Tukwila: 139 units in three -story condominium buildings ranging from 10 to 25 units per building, 32 units in four -plex condominium facilities, 18 units in duplex townhouse condominium structures and 10 new single - family lots. b. The potential stimulus,for conversion of other units on the hillside to condominium use, if this project is successful. Transportation /Circulation a. Increase of 1,234+ vehicular trips per day to and from the proposed units including 100 trips to and from the single - family property via S. 151st Street and 62nd Avenue S., and 1134 trips to the south on 62nd Avenue S. from the multifamily units. Over 91% of total vehicle trips will be to south via 62nd Avenue S. b. An 11 per cent increase in the daily and peak hour traffic on Southcenter Boulevard which is currently 11,300 at 62nd Avenue Southeast (i.e., addition of 1,234 ADT's). c. A substantial increase in traffic volume on 62nd Avenue, south of the site, from an estimated 400 to about 1,600 trips per day. d. Slightly increased ridership on Metro Transit Routes serv- ing the area. 11 e. Increased potential for conflicts and accidents from pedestrian, bicycle and vehicular uses of road area. Public Services a. Increase of 10% or less in fire, police and aid service calls. b. The residences may contain a potential of 60 to 100 school age children, about half of whom will be in the elementary grades. c. Increased utilization of City, County and State parks and recreational facilities and programs near the project area. d. Increased private and public maintenance requirements for . roads and utilities. e. Increased demand on hospital services in the area. Utilities a. Increased use of electricity, natural gas, telephone ser- vice, water, sanitary sewers, solid waste facilities b. Storm water discharge will include provision for retention and pollution separation to minimize potential hazards. See Appendix A for detailed utility consumption figures. Energy Small, but incremental, increases in long -term use of energy resources at this site, including estimated consumption of about 400,000 kwh per month for electricity and 3000 to , 4000 therms of natural gas. Human Health Proposed ponds may impact water quality if not maintained and remain free flowing. Aesthetics a. Loss of natural features and replacement by human settle- ment and activities. 12 b. Potential impetus for development of similar character in the area. c. A change in the visual character of the area as seen from I -405 and Southcenter, significantly different frcm exist- ing development on the hillside. d. Creation of views for a majority of the units to the Green River Valley, Mt. Rainier and areas south of Tukwila. Risk of Explosion, Upset or Hazardous Emission Blasting will take place on southeast corner of site to remove part of an exposed bedrock formation. C. Alternatives to the Proposal 1. Use of site for single family (R -1) and fourplex (R -3) under existing zoning. 2. Maximum utilization of the property south and west of the ridge line for R -4 zoning, R -3 along the ridge line, the balance of the site in R -2 and open space. (See Figure 7.) 3. R -2 on Lot 8, R -3 on Lot 9, R -4 on Lot 10. (See Figure 3.) 4. All uses as proposed except the single - family area retaining as open space and either a covenant to keep as a natural area or deeded in fee to the City as passive open space area with a site for a water reservoir facility. 5. Modify size and configurations of proposed use zones. 6. No action. D. Measures Proposed to Mitigate or Eliminate Adverse Impacts The following mitigating measures that are feasible and economi- cally practical with available technology have been suggested for mitigation or elimination of adverse impacts, including: Soils, Geology and Topography 1. Requirement for additional soil tests on building sites, and certification by qualified specialists of adequate foundation design for each structure. 13 2. Retention of storm runoff waters during and after construction to reduce water contamination by suspended silts and to reduce peak flow volumes. 3. Inclusion of no -build areas on steep slopes, storm water pond - ing areas and areas- containing major groupings of vegetation. 4. Control of grading operations to avoid peak rainfall periods. 5. Replanting of exposed slopes. 6. Use of decks, cantilevering to minimum disturbance of steep slope areas. Traffic and Transportation 1. Control of traffic flow through site design to provide major access to Southcenter Boulevard, an arterial, via South 62nd Street. 2. Allow site access to Northeast corner of site which goes through single - family areas, only for proposed single - family lots. 3. Cooperation with adjacent property owners to the south and east to improve 62nd Avenue S. and S. 153rd Street for visi- bility, width and general circulation. Air Quality 1. Specification of construction practices to minimize' air pollution. 2. Implementation of sprinkling during construction to control dust. Water Resources 1. Use of landscaping to contain runoff and decrease velocity of overland flow. 2. Use of energy dissipating devices on drainage lines descending steep slopes. 3. Consideration of reduction of extent of impervious surfacing. 4. Use of siltation devices in the interim drainage system. 5. Proper use and maintenance of oil- separating devices ini the storm drainage system. 14 6. Use buiding roof and parking lot surface designs to .detain water. Flora 1. Minimal and selective vegetation removal, particularly in the northeast and easterly portions of the site. ' 2. Predominant use of native species or compatible ornamental varieties in landscaping. 3. Hydroseeding of cut and fill areas within short time frame of grading. 4. Native growth protection easements and no -build zones placed on areas with slopes 25 per cent or greater and around exist- ing surface water holding ponds. Fauna 1. Maintain water habitat by proper use and maintenance of silta- tion and oil separation devices in the interim and permanent storm drainage system. 2. Phased development to allow existing wildlife to adjust and migrate. Noise 1. Incremental traffic noise impacts can be reduced by phasing project over a two - to three -year period. 2. Limitation of construction activities to normal working hours (i.e., 7 a.m. to 7 p.m.). 3. Use of heavily insulated buildings, double -pane windows, land- scaping, fences and earth berms as noise attenuating measures. Larger structures on south face of site will baffle some noise from I -405 and I -5. Light and Glare 1. Use of landscaping, fencing and building orientation to block headlight glare into dwelling, units. 2. Site plan review by City Staff of orientation of parking areas, with respect to dwelling units. 15 Public Services 1. Provision of through - circulation corridors for emergency vehicles and police through the entire site; direct access to all buildings for fire - fighting equipment. 2. Development of recreational facilities and preservation of open space within the proposed development. (Recreational Space Plan required by Ord. #1040) 3. Stringent design requirements and equipment specifications for storm drainage control. 4. Requirement of regular maintenance program for privately owned roads and utilities. 5. Phasing of the project will delay impacts on the school district. 6. Cooperate with adjacent property owners and City for develop- ment of roads and public services in the area to serve the site. Utilities 1. Provision of hookups to existing dead -end water services to provide better fire flows and water service. 2. Linkage of other utilities to provide better service for the south face of Tukwila Hill. 3. Use of weather stripping; wall, floor and ceiling insulation and insulated glass in the dwelling units. 4. Use of canon -wall construction as materials - and energy- saving devices. 5. Installation of water - saving devices in the dwelling units. Risk of Explosion, Upset or Hazardous Emission 1. Required procedures and safety standards will be followed if blasting operations are necessary including use of a licensed and bonded blasting firm. 2. Advance notice to adjacent property owners. 3. Provide bond to endimify for damages. 16 Aesthetics 1. Retention of natural vegetation to the maximum extent possible. 2. Alteration of building designs to minimize occurrence of typical rectangular structures. 3. Retention of natural areas and additional landscaping and screening between different use areas. Preservation of trees along ridge line will screen project from single - family homes to the north. 5. Add an additional 30 to 40 foot buffer ,zone along the north property line to the existing wooded area on the southerly perimeter of the school playfields. E. Unavoidable Adverse Impacts 1. Elements of the Physical Environment Soils, Geology, Topography 1. Potential erosion of soils during clearing and grading. 2. Extensive excavation of rock for roadway access at 62nd Avenue S.E. 3. Some alteration of topography by cuts and fills. Air Quality 1. Some degradation of air quality in the project vicinity. 2. Increase in suspended particulates from fireplaces, resi- dential heating and construction activities. Water Resources 1. Increased runoff and decrease in water quality. 2. Slight alteration of stream flow characteristics in a year -round stream. Flora Removal of 50 percent of natural vegetation on the site. Fauna 1. Reduction of quality and quantity. of wildlife habitat within the project area. 17 2. Reduced number and diversity of species on the site. 3. Potential impacts on water quality and downstream fish habitat. Noise Increases in. short -term noise levels during construction and minor increases in noise levels from traffic after construc- tion greatest along 62nd Avenue, south of the site. Land Use Commitment of 15 Acres to Urban Residential Use 2. Elements of the Social Environment Population 1. Population increase of approximately 450 to 500 residents on the site. 2. Addition of 60 to 100 pupils children to school district. Transportation /Circulation 1. Increase of 1,234 trips per day to and from the project, primarily at the southeast corner of the site. 2. Short term construction- related increase in local traffic volumes. 3. Traffic volumes on area streets after completion of pro- ject will increase substantially on 62nd Avenue south of the project and by minor amounts on other roads. 4. Increased potential for conflicts and accidents fromlhuman and vehicular uses of area roads. Utilities Increased use of electricity, natural gas, telephone service, water, sanitary sewers, solid waste facilities. (See Appendix. A for detailed utility consumption figures.) Energy Small, but incremental, increase in long -term use of energy resources. 18 Aesthetics 1. Loss of natural features and replacement by human settle- ment and activities. 2. Potential secondary development of similar character. 3. Visual character of area, as seen from I -405 and South - center will be significantly different from existing development on the hillside. 4. Creation of views for a majority of the units to the Green River Valley, Mt. Rainier and areas in South King County. 19 II. DESCRIPTION OF THE PROPOSAL A. Proposal; Name of Project Sponsors The Northward Development Company of Bellevue, Washington,, re- quests approval of a rezone with certain conditions as set forth in Appendix F to allow for four new zoning areas: R -4, R -3, R -2, R -1 9600 respectively. The areas, as shown in Figure 2 would pro- vide for.134 condominium units in the R-4 area and buildings rang- ing from 10 to 25 units per building with an accompanying -201 parking places. The R -4 would cover 6.16 acres. The R -3 zoning in the center portion of the site (3.15 acres) near the existing ridge line would accommodate 32 units in eight 4 -plex buildings, two stories in height with parking for 64 cars. The northwest corner of the property, 2.23 acres near the existing R -4 zoning on the Graden Smith property, would be developed with 9 duplex, town- houses totaling 18 units, with attached covered parking places for each unit. The northeast corner of the property, 3.19 acres, would provide for 10 single - family .detached-dwelling units, open space and a major retention pond for surface runoff. Separating the four areas would be 2.56 acres of open space areas protected by covenants from building or clearing. B. Location of the Project (See also Figure 1) The project is located on a 15 -acre site on the south face of Tukwila Hill in the City of Tukwila, northeast of the interchange of I -5 and I -405 south of Seattle. Legal description of the property is lots 8, 9 and 10 of Interurban Addition to Seattle. C. Other Agencies Maintaining Files on the Project There are no other agencies known to maintain a numbered file on the project. D. Construction Phasing The project is proposed to be phased for construction beginning with the R -4 portion of the property on the southwest, then moving 20 to the lower density zones. The single - family lots may be devel- oped earlier if the market is favorable and platting approval is obtained. The entire project is proposed to be phased over a two to three year building period, with major construction occurring in the dry seasons of 1979 to 1981. Recreational facilities (tennis courts, swimming pool and recrea- tional building) will be developed as part of phase one as well as utilities for most of the site, all roadways and other common facilities. Construction of additional dwelling units on the site in the next two to three years will be in response to detailed market studies and demand analysis. The single family area, its roads and utilities must be part of a separately approved sub- division application. E. Major Physical and Engineering Aspects of the Proposal The streets, lots, building configurations, parking arrangements, open space areas, access points, drainage channels, trails, recre- ational facilities and other elements are shown in Figure 2. These are also supplemented by other drawings submitted as a part of the zoning application, including but not limited to: 1. Site analysis, topography, tree and major vegetation group- ings, drainage patterns, view analysis. 2. Development concepts including access and circulation patterns. 3. A grading Plan including cut and fill areas. 4. Utilities plan. 5. Site sections. 6. Landscape Plan and Recreational Space Plan. 7. Architectural details including elevations. 8. Typical development, unit types. 9. Phasing of construction. The application for rezone will designate various areas of the site for specific zoning uses with the understanding that a Planned Unit Development approach is being applied, to guarantee 21 16 1Q. !4915 eo csr- s 26 41t-1i � lb e 114518 2? 3 ISE 1 f 1 70 1 73 1 1 75 I 2Bv 67 a y yp0 NEBO 0 149® 14923 ❑o 14331 1 II i t 7 1 1 1 1 1 I1 I 1I i t II 111 I� 1 5304 Z11z waw/ Juaw! - I /00 i53I0 FIGURE 3 GENERAL VICINITY EXISTING ZONING AND DEVELOPMENT PATTERNS Legend: minus Project Boundaries mom= Zonine Boundaries I�r1H 15 1VEW C /TY HA L.L.. CP. 0 0 J 0 6 22 �``�F11�e:: 11 IA -,' � of 1« I j 1 L?SS 1 Ins 67 J\ „ ao0 n_Q1=3o 'S /49TH 1d , \ s •I� \\ y . \ �V \ 22 aQO /5 /ST 9 arit 54. 37 R'4 a 61.10111gi 3�wB Ju 4 -. pI � a �\1 1 ,t o 1 W alli 1112 "Mr= INN asoiounnnnrtn t nnn taunnuonat i . 1 . fFW/401144:9„ • ir,742,..A., 0 ; 154) ° o p-- � IJ971 p o A vo -3 Medium Density Multiple R -4 High Density Multiple .MN 15 /VE'D1f Lint PIA LL 23 • • a) • • • O "Cb m V) 04 t/) W H rr C fD G" fD b tri • A 0 M a) r•r 0 N 0 • • • •.‘ • .$ •.. OP { tV .AL VSQETATlog ttf041104 1N ;.t • MINIM /M. • 1 AA LIN hiscip0 •••••••..•••• 1 • •..•••• vans DOUSU . uqa • Wu4t 11 1976 McCarty, Jbt ps. 747 -4060 .— that the site design is consistent with the goals and policies and the map portion of the recently adopted Tukwila Comprehensiv Land Use Policy Plan. The proposal would gradually reduce the density of dwelling units as one moves from the south portion of the prop- erty northward and east. Steep slope areas are preserved in an open space system. Existing trails in the area are linked through the site. Major tree groupings have been identified as reserved for preservation in the conceptual site plan. Trap small pond areas would be enlarged and utilized as a part of the open -space system for the collection and detention of peak storm runoffs. The more dense development is proposed to be restricted to the more level areas of the southerly portion with less existing vege- tation. Most of the desirable types of trees such as the coni- fers, large maples and associated understory will be left in nat- ural areas. Access is proposed for most units over South 62nd at the southeast corner of the site, with only the 10 single - family lots gaining access to the northeast. However, major cuts and fills with accompanying retaining walls will be required at the southeast corner of the site to provide access to that inter- section. The site plan provides for through circulation for emergency vehicles only, through push -down barricades. The entire project will be units for sale. No rental units are proposed as a part of the project. Community facilities will be provided for the entire project, a homeowners' association de- veloped and protective covenants, restrictions and conditions filed as a part of the overall condominium subdivision approval. Price range of the units will be determined by market forces, but generally range from $42,000 to $65,000. At present the site is totally undeveloped. Other than logging, past activities on the site were limited to provision of fill in the 62nd Street right -of -way at the northeast corner of the site for a distance of sane 200 to 300 'feet. This partially impounds water flowing off the elementary school site resulting in a small pond. 25 Clearing and grading of approximately 50 percent of the site would be required to implement the proposal, leaving major buffer zones along all four sides, particularly the north, east and west to screen the project from adjacent uses. The open space system along the easterly ridge line would both provide a linkage to the existing wooded and open space areas on both the school yard and the property lying to the east. F. Relationship of the Proposal to Existing Comprehensive Land Use Plan and Zoning Regulations 1. Tukwila Comprehensive Land Use Policy Plan The recently adopted Comprehensive Plan contains several ele- ments, including a Goals and Policies section and a map that serve as a land use guideline to assist the City's review bodies and staff in evaluating zoning applications and land use matters. As depicted in Figure 5 the site is divided into three•as follows: The southwest corner is high density resi- dential (over 16 units per acre) the central portion and majority of the site medium density residential (7 to 16 units /acre) and the northeast corner low density (0 to 6 units /acre). The ridge line is used as a natural demarcation between medium and low density. The proposed site plan and proposed development have been designed to be as consistent as possible with the map, and the directions given to the previous property owners by the City Council, Planning Commission and City staff during the com- prehensive planning process. The plans also reflect the Goals and Policies section of the Plan as summarized below. Residential Element: Section 1: Neighborhood Objectives and Policies Objective 1, Policy 1: Buffer zone boundaries are based on topographic features. 26 ❑ LOW DENSITY ENTIAL (1 -6 Du/Ac) MEDIUM DENSITY RESIDENTIAL (7 -16 DU /AC) HIGH DENSITY RESIDENTIAL (17+ ❑ *FIROL CO IEr CIAL ❑ LIGHT INDUSTRIAL HEAVY O JUST['; I /1,L ❑ PUtzLICC PP,CILITIES RKS OPEN SPACE e, i1 SPECIAL DEVE RENT C =MOM 1MAREAS 0: STEEP MOPES, WATER SURFACE, N D MERIT IATUR 1L LANDS. THIS OEStQ1W ON DOES NOT PO au= DEVELOPMENT, RATNER, IT OEFn.TS AREAS TVUX COMM 1 MADAN DEVELOPMENT MUST RESPOND DENSMVELY TO GERMAN EMWROADVIIA. PROWS. mom PLANNING AREA BOUNDARY noun CITY BOUNDARY DU /AC). SITE NSIDIE ATI // F. �II111111 111111 'IIIflhllntn inn FIGURE 5 PRELIMINARY 0 PREH 7UNNAL&' EMS VE LAN1 USE PLAN M PLARS1:02 &EAs�G^Q 27 Policy 2: Subject property has a park and school playfield on the north and the applicant proposes buffer areas on the north and east to separate them from undeveloped areas. Policy 4: Objectively, vehicular traffic related to medium and :high density units can be channeled to the south through apartment and commercial zones. Access to arterials is direct via,62nd Ave. So. (Note: Use of through lane for fire access i must have access controlled with breakdown barricade to meet this policy. Objective 2, Policy 1: The proposed rezone and site plan approval, utilizing a vary - ing density of development, would provide for a medium density transition area between high and low density residential areas. Objective 2, Policy 2: This development would be located functionally convenient to primary arterial streets, shopping, employment and other facilities within the Tukwila planning area. Objective 3: Maintenance of buffer areas on the north and east, particu- larly the steep slope area, will provide ccmpatibility;with this objective. In addition, the following items as incor- porated into the proposal are responsive to policies in.this section: Policy 1. Screening of adjacent uses. Policy 3. Undergrounding of all utilities. Policy 4. Maintenance of natural open space areas. Policy 5. Provision of guest' and recreational vehicle parking. 28 Policy 6• Provision of trails to link activity nodes in the area. Policy 7. Encouragement of recreational open space within multi- family development. Section 2: Housing Objectives and Policies Objective 1, Policy 1: With the proposed development, because of its size (i.e.: 15 acres), it is possible to encourage housing development with a diversity of housing types. Duplexes, townhouses and four - plexes are envisioned on the less dense portions of the prop- erty, and the R -4 area provides a mix of condominium units with 2 and 3 bedrooms. Ten single family detached units are proposed. Policy 2: Townhouses, condominiums and single family lots are proposed for the site - all owner occupied. The proposal has been developed to reflect and be compatible with the following Objectives and Policies:.` Objective 2, Policy 3: Insulation, insulated glass, and building siting will be used to reduce impact of freeway and aircraft noise. Element Goals. General Goals 2, 5, 6,'8 Natural Elements 1, 2, 3 Open Space 1, 2 Residence 1, 2, 3 Transportation /Utilities 1, 2, 3, 4 29 Element Natural Environment Open Space Residence Transportation Utilities Sanitary Sewer Storm Water Systems Underground Utilities The following goals may Objective Goals 1 1, 2, 3 3 1, 2, 3, 4 4 1, 3, 4 5 1 6 1 8 1 1, 2, 3, 4, 6 2 1, 3, 4, 5, 6, 7 3 2 (See Previous Text) 1 3 6 2 5 6 7 8 inconsistent as presently proposed. Other policies listed were considered not applicable. Goals General Goals: None Natural Environment: None Open Space: 3 - provide recreational people of Tukwila Residence: None Transportation: None Objectives /Policies Natural Environment 2 -1 Obj. /Pol. Retain wooded hillsides for wild- life 3 -1 Some limited development may occur in areas of 20 to 25% slope, lhow- ever none in excess of 25% 1, 2, 4, 5, 6, 7, 9, 10, 11, 12 1, 2 3, 7, 8 2, 4, 5, 6 4, 5 1, 2, 4 1, 2 1, 4, '5, 7 with the application and objectives; not opportunities for all 30 Natural Environment 6 -2 Some rock outcroppings may be modified or removed 8 Sane onsite studies have provided' environmental data that may be different than that of the City's environmental data bank. Open Space 2 -4 Some areas of existing trails may be rerouted by development and public access restricted. 3 -3 No trail easement for public access are proposed at present Residence 3 -1 No low income housing is proposed and in the 199 units 3 2 Transportation 1 -1 Some ,conflict between parking and access may occur. 1 -4 No public dedication of rights -of- way is proposed except in single family subdivision. 6 -4 Trails, walkways may not be planned for handicapped 8 -7 Utilities to link existing services may cause some disruption of natural areas. 2. Zoning Code The proposed uses will comply with the appropriate sections of the Zoning Code (Title 18, TMC) for R -4, R -3, R -2, and R -1 9600 classifications. All density, bulk requirements, site coverage, parking and other requirements have been reviewed and incorporated in the plans. 3. Building /Fire Code Provisions of the UBC and Fire Codes will be observed and changes made if necessary to comply. 31 III. EXISTING .CONDITIONS, IMPACTS AND MITIGATING MEASURES INDEX OF ELEMENTS OF THE ENVIRONMENT A. Elements of the Physical Enviroment Earth Geology. 34 Soils 34 Topography 34 Unique physical features . . . 34 Erosion 34 Accretion /avulsion NA Air Air Quality 42 Odor NA Microc lima to NA Water Surface water movement 45 Runoff /absorption 45 Floods N`°' Surface water quantity 48 Surface water quality 48 Groundwater quantity 48 Groundwater quality. 48 Public water supplies 70 Flora Numbers or diversity of species 50 Unique species 50 Agricultural crops NA Fauna Numbers or diversity of species 52 Unique species 52 Barriers and /or corridors 52 Fish or wildlife habitat 52 Noise 53 Light and Glare 55 Land Use 55 Natural Resources .57 Rate of use 57 Nonrenewable resources 57 Risk of Explosion or Hazardous Emissions . . . 58 32 B. Elements of the Social Enviroment Population 58 Housing 58 Transportation /circulation Vehicular transportation generated . . 60 Parking facilities 60 Transportation systems 61 Movement /circulation of people or goods 61 Waterborne, rail and air traffic . . . •! NA Traffic hazards 62 Public Services Fire 64 Police 64 Schools 65 Parks or other recreational facilities 66 Maintenance 66 Other governmental services- 64 Energy Amount required 69 Source /availability 69 Utilities Energy Communications Water Sewer Storm water Solid waste Human Health (including mental health) Aesthetics , • Recreation 66 Archeological /historical Additional Population Characteristics 'Economic Factors 69 72 70 70 70 73 A. Elements of the Physical Environment 1. Earth a. Existing Conditions Geology and Soils A ground reconnaisance of the site was conducted by a soils engineer -(see Appendix A for report). Shallow glacial till, weathered on the upper two or three feet, grades downward into a glacial sand and gravel formation. A bedrock formation crops out on the southeast property corner. Both bedrock and till provide excellent founda- tion strength. The till appears to be stable, with no evidence of sliding. Soils on the site are not analyzed in the Soils Conserva- tion Service's survey of King County, other than as :gen- eralized "Urban Soils." The thin till soils observed on the site probably have a low productivity potential other than for forest. No unusual soils conditions were obser- ved, except for the exposed bedrock, which poses no prob- lem to development except difficulty of excavation. Topography The site has wide ranges of topography and slope with .a ridge line as depicted in Figure 6, running from, the northwest corner of the site southeasterly to the 'east property line. Elevation of this ridge line varies from 230' to 255.6', but generally averages 240' in height. From this ridge line, the property falls off to al low point near elevation 140' in the northeast corner' and along the existing drainage channel. The property also falls off to the southerly property line, at roughly 180'. The westerly property line drops from 230' on the north- west to 165' on the southwest. The average slope from the ridge line to the northeast corner is 21 per cent and the average slope from the ridge line to the southwest corner is 12 per cent. The slope, ridge line and two low points 34 where some ponding occurs are depicted in Figure 6 - topography and 10 - drainage basins. b. Impacts Geology and Soils As noted below, a considerable amount of soils relocation will take place on the site, with cuts of 20,000 cubic yards, balanced by 16,000 cubic yards of fill. Approxi- mately4,000 cubic yards of excess material will be used in earth berms or exported from the site. The bedrock out- cropping will also be reduced for the southeasterly road- way entrance. Most of the rock is expected to be used on the site. The impact of the soils relocation on site will be related to the topography. Till soils are highly erodable if exposed on steep slopes. The stability of cuts and fills, as well as groundwater will be critical at the foundation locations. Tbpography Grading operations should have a range of effects on the topography. •Significant excavation will occur at the southeast corner of the site to accommodate the access point. Total excavation of this area will be approxi- mately 6,000 cubic yards, largely bedrock. In certain areas, as depicted in Figure 7, cuts and /or fills will occur in order to provide for building pads, parking areas and roadways as a part of the overall site development. The proposed buildings would utilize existing contours such that foundation excavation would be minimal. 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RACILD TO lallpff•• num% mom. • r!bUKt y -1 GEOLOGIC CHARACTERISTICS I[J TUKWILA PLANNING AREA c 1 am+ c m x 0, KO c 0 • Features Foundation Stability • Seismic Stability' Slope Stability Alluvium (Qa) Laid down by rivers after retreat of glacier. Primarily silt, clay, with some peat. . w : ',.-" Lacustrine deposits " (Qic) • Deposits laid down by great lake in Duwamish Valley when glacier blocked drainage to the north. Silts and clays. f. ,. =t: Outwash deposits (Qvo) Ground moraine laid down by Vashon glacier which has been washed by streams and melting ice. Sand and gravel. O O 9 Ground moraine (Qvt) Also called Vashon till. This is the material which fell out of the ice as the Vashon glacier melted back into Canada. Compact mixture of clay, sand, gravel, and boulders. O O 0 Glacial, non- glacial deposits (Qu) Glacial and nonglacial materials laid down prior to Vashon glaciation. Undifferentiated de- posits of sand, silt, clay, gravel and till. 0l -- Bedrock (TpTb) Includes sedimentary and. volcanic rocks which formed in preglacial times. Folded sedimentary rocks of Renton Form- ation. Also includes intruded basalt. O O 0 O GOOD O FAIR POOR IAdopted from: Preliminary Geologic Map of Seattle and Vicinity, Washington, U.S. Geological Survey, 1962; Donal Mullineaux, Geology of. the Renton, Auburn, and Black Diamond Quadrangles, King County, (Geological Survey Professional Paper) No. 672, 1970; and An Ecological Study of the Kent Lowland, Kent Planning Department, 1971. 39 FIG. '9 -2 SOIL GROUPS: DESCRIPTIONS AND CHARACTERISTICS TUKWILA PLANNING AREA GENERAL SOIL TYPE MARSHY SOILS ALLUVIAL,SOILS TILL SOILS OUTWASH SOILS ROUGH. BROKEN AND STONY LAND General Description Wet areas, depres- sions of peat and muck. Level, gen- erally shallow soils. Deep sedimentary soils of silt, clay and some peat developed in valley alluvium. Thin soil layer developed overim- permeable glacial till or bedrock. Relief gently rolling or hilly. Gravelly, dry soils developed over glacial out- wash deposits. Relief generally rolling or hilly. Variety of soil types found on steep slopes. Bearing Capacity Low Low High High Low Erosion Hazard Slight 9 Slight Slight Moderate Severe Internal Drainage Poor Poor Fair Good Fair Arability Fair Good Fair ' Poor ' Poor Characteristics related to urban development . High water table and low bearing capacity require filling prior to development. These areas serve to store runoff, and ifdrained, an increase in peak storm runoff will occur. High water table and low bearing capacity require much site prepar- ation prior to development. High fertility of soil well suited to agriculture. Hardpan occurs only a few feet from soil surface and restricts downward percola- tion of water. Soils willsupport heavy structures. Slight erosion, increasing to moderate erosion in slopes exceed - ing 15 %. Excessively dry soils which are subject to ero- lion if cleared. Good soils for buildings with basements. Pro- vide good drainage for septic tank drain fields, but may cause possible groundwater pollution. Steep slope pre - cludes construc- tion of roads. Intense develop- ment impractical. High erosion hazard in these soils, especial - ly if stripped of vegetative cover. Soils are gen- erally unstable. Source: Soil Conservation Service, U.S. Department of Agriculture, Soil Survey of King County, Washington, 1973. 40 utilized for roadway subsurfaces.. Wherever possible, topsoils can be stockpiled for use in landscaping, berms and other surface treatment following construction. In some instances excavation for foundation and parking areas will be fairly extensive to accommodate conventional foun- dations. Significant grading and cuts and fills will be required to provide a roadway linkage for emergency ve- hicles from the northeast corner to the central portion of the site. load grades will range from 2 per cent to 14 per cent except the fire lane linkage which will be 16 %. The entrance grade is planned to not exceed 12 per cent. Existing land contours will be altered by excavation, and relocation of fill material on the project site. No materials are to be imported and only excess fill mater- ials exported. Excavated materials will be balanced on the site during preparation for construction. Erosion On grades which exceed 8 per cent through the site for long distances increased runoff could create soils slip- page potentials. Eroded sentiments carried by runoff could cause turbidity in the stream that runs through the site. c. Mitigating Measures Geology and Soils Installation of siltation basins, drainage velocity dissi- pators and foundation drainage systems could mitigate the adverse impacts of soil erosion and reduce the potential for soils slippage. Restricting grading operations to periods of dry weather and replanting exposed slopes could reduce soil erosion. Installation and maintenance of temporary and permanent drainage control structures could reduce the sediment load that might enter the natural stream system. 41 Detailed_ soil borings and analysis on all building loca- tions should be undertaken by qualified soils engineers and consideration be given to rearranging proposed build- ings if soil conditions dictate. The soils and slopes to be encountered are not thought to be .unusual for the area and are commonly built; upon safely, provided engineering recommendations are followed. A detailed engineer's report on foundations for each phase will be supplied with final building and grading plans for that phase, together with recommendations on standing cuts or slopes, filling materials, compaction and drainage systems. Topography tine of rockeries and retaining walls Gould reduce the extent of topographic alteration. Use of pole or ,pier - type foundations as well as architectural design varia- tions on steep -slope areas could decrease grading re- quirements and thus mitigate adverse impacts on existing topography. Reducing the extent of development would reduce grading requirements. 2. Air Quality a. Existing Conditions The most significant factor affecting ambient air quality in the vicinity of the proposed project is automobile traffic and airplane traffic from Sea -Tac Airport, Boeing Field and Renton Field. The site is located on the south face of Tukwila Hill, which is bound on the south by,I -405 and on the west by I -5. Sampling of particulates and sulfur dioxide has been carried out at Southcenterisince late 1976. Air pollutants contained in vehicular exhaust emissions include carbon monoxide (CO), hydrocarbons (HC);, and 42 oxides of nitrogen (NOx), of which carbon monoxide is the pollutant of most concern. Carbon monoxide levels were monitored during 6 weeks in January and February of 1977. Maximum 1-hour concentrations did not exceed 11.5 parts per million (ppm) at any time. This is one -third of the maximum 1 -hour standard of 35 ppn. Eight hour averages were under 4 ppn. Traffic congestion, characterized by a large number of slow - moving or idling vehicles, occasionally results in high CO levels in the area, particulary on days when the wind is light and stagnation or inversion conditions exist in the Green River Valley. Prevailing wind is from the southwest in winter and the northwest in summer. The average daily traffic volume along Southcenter Boulevard is 11,000 vehicles per day, on I -405 66,400, with vehicles concentrated periodically around Southcenter. Suspended particulates are another source for air pollu- tion, chiefly responsible for reduced visibility in the Puget Sound region. Sampling developed by the Puget Sound Air Pollution Control Agency (PSAPCA) indicated suspended particulate levels ranging around 45 mg per cubic meter (ug /m3) in 1976. Compared to 1975 maps for the same pa- rameter, Tukwila and King County in general appear to be experiencing an increase in suspended particulate levels in the atmosphere; in 1975, the same area showed an annual mean of 33 ug /m3. Traffic along the above mentioned roads can affect pollut- ant level in the project area, particularly during periods of low wind velocity. Vehicular exhaust fumes tend to follow the upward slope of the site and odors from this source would be most noticeable with the onset of morning vehicular traffic. Airplane exhausts occur in the area and are a part of the general air quality. 43 b. Impacts Unless an increase in congestion at intersections is caused, air pollutants generated as a result of this pro- ject should not have a significant effect on local air quality. The peak hour traffic levels, in the range of 125 vehicles per hour, slightly more than two cars per minute, on 62nd Avenue South, should not cause any 'great increase in concentrations in the area. The rise in pol- lutants in the significant areas, along Southcenter Boule- vard and I -405, may rise in proportion to the traffic levels. This project should add less than 1% to theltraf- fic through that corridor. (Estimating 70% of the site's A.D.T. (794) allocated to Southcenter Parkway Boulevard, between 62nd Avenue and the Southcenter access overpass, where total A.D.T. is nearly 80,000 (combination of'I -405 and Southcenter Boulevard).) No significant increase in the probability of violations of local air quality stand- ards is therefore expected as a result of this project. Mitigating Measures Vehicular exhaust emissions should be reduced vehicle emission standards became effective vehicles are replaced. If peak hour traffic Southcenter Boulevard result as federal and older volumes on in significant congestion at the intersection of 62nd Avenue South and Southcenter Boulevard, provision of turning lanes may be considered. Although not within the scope of this project to effect, widening of I -405 in this area could reduce congestion and improve air quality. Sprinkling could be implemented during construction per- iods to reduce airborne dust. 44 3. Hydrology a. Existing Conditions Stormwater runoff generated by the site currently drains in three distinct directions. The northeast portion of the site drains into a well- defined drainage swale. This swale, which also receives drainage from the developed area to the north, broadens to form a shallow pond about one foot deep and then runs from north to south eventually emptying into the I -405 storm drainage system. As well as conveying stormwater runoff, a small base flow of approxi- mately 0.1 cfs exists in this swale and acts as the source of the shallow pond. The south portion of the site drains into the currently undeveloped property to the south. There are no distint drainage swales in this area. Runoff travels essentially as sheet flow until it is intercepted by S. 154th Street and routed into the I -405 storm drainage system. A shallow depression which has .a maximum depth of approxi- mately 3 feet exists adjacent to the site's west boundary. Approximately 2 1/2 acres of the site as well as 1 1/2 acres west of the site (the only offsite area draining into the site) drain into this depression. This drainage is apparently the source of standing water at the depres- sion which is probably seasonally intermittent. b. Impact The existing drainage patterns at the site will be basi- cally retainied. Stormwater runoff from the northeast portion of the site (which is proposed for the least in- tensive development) will pass through oil -water separator catch basins and then be conveyed to the existing drainage swale at the east boundary. As a result peak flow rates will increase in the swale. However at points A and B as shown on the Existing Drainage map, the peak 10 -year re- 45 FIGURE 10 EXISTING DRAINAGE )//, / .c \\‘4\\ ' SITE Emma aeat Imo TYPICAL J 711AW/(q C //Y M&L &POO CpvSCitK7g1 ) \ TR ASSOIAO CIATES` — 111N•109r M M! Mb.." vs. 4114.0711 / 0 00 MO bo ESISiridi 1 46 ,/ r- F I GURE 11 ( \ \ • DRAINAGE PLAN ‘ / f/ r ( mouii bakvair Tot/ nowt sefrARArats CONVEY ID LOST& 6 DRAMAM 110Iu: 1. • \ • . • • ( • \\ \ AffMNAl CONVEYAIr E. ROLITINI DETIMION PACIII1111, AND DISCNAR6I 10 PROPOSED PORM DRAIN SITE Val es A TRIAD ASSOCIATES •HOM *aft ealwale■ WID• 414"Orn WA WU ell Kea ILiiP aystiritereN) \,IperION OF: NSW E`3,71vP 23N, P4( 0 100 tO0 t 1 turn interval flows should increase by only 30% and 20 %, respectively (from 7.7 cfs ' to 10.1 cfs at A and from 9.9 cfs to 12.1 cfs at B). Due to the relatively steepichan- nel slopes the existing capacity of the downstream system should be adequate to accommodate this flow rate increase. Because of the more intensive proposed development of the south portion of the site, stormwater detention facilities will be provided to limit the 10 -year peak discharge to the south to approximately the existing 1.2 cfs 10 -year peak flow rate. Discharge fran these facilities will probably be made into a storm sewer line which should be built at 62nd Avenue South in conjunction with improvement of that street to facilitate this and neighboring develop- ments. Such a storm sewer would then discharge into the I -405 system at Southcenter Parkway. The depression along the west boundary will probably be developed as a shallow pond for use as an amenity to the project. However runoff from a portion of the area cur- rently tributary to this depreession may be routed into the detention facilities at the south portion of the site. Clearing, grading and construction of extensive areas that will be covered with impervious surface materials will significantly alter existing runoff and absorptions Char- acteristics. Site runoff could be expected to increase by more than five times in some small areas. Absorption of precipitation will also diminish signifi- cantly as a result of interception by parking !areas, roads, rooftops, and other impervious surfaces. Approxi- mately 60 per cent of the R -4 dwelling areas and 40 per cent of the duplex and single - family areas would be covered by such surfaces. Average site coverage through- out the project would be approximately 50 per cent. 48 Surface water quantity would be adversely affected to the extent that runoff is increased and absorption is decreas- ed. Reduced absorption could result in lower low- stream flows. Clearing and grading activities will cause erosion of site soils during construction periods. Eroded sediments could enter the stream as runoff and result in turbidity. Run- off from parking areas and roads could contain petroleum product residues. In addition, runoff from impervious surfaces would have slightly increased. temperatures and nutrient. levels. The adverse. impacts on the water quality would be most significant from runoff during seasonal low flow periods. Deep excavations required for placement of large buildings on the hillsides in the project area could intercept groundwater movement. c. Mitigating Measures Runoff /Absorption Landscaping features, such .as berms, gardens, and porous walkways, as well as grassy areas and natural areas that would induce vegetation, could detain runoff and decrease the velocity of overland flow, substantially reducing peak runoff volumes. Use of the two existing ponding areas to detain runoff and detention facilities in the more dense parts of the proposal could decrease runoff and increase absorption. In some areas where feasible, the combination of splash blocks and bored recharge shafts might be utili- zed to increase absorption. Perforated steel piping for underground portions of roof drains could permit greater absorption and. reduce surface runoff. Reduction of the extent of impervious surfacing could be encouraged to decrease the quantity and rate of runoff. 49 Surface Water Quantity Mitigating Measures suggested by Triad Associates in Appendix B for increasing absorption and detention could mitigate the potential impact of peak and reduced. low flows. Surface Water.Quality t. a of siltation devices as a part of interim drainage 'system during.construction could reduce the potential for turbidity and sedimentation in the stream. The storm drainage system could be equipped with oil- separating devices which, if properly maintained, would reduce the potential for petroleum product, residues to enter surface waters. 4. Flora a. Existing Conditions Like many of the areas surrounding the Green River Valley on the plateaus, the site of the proposed development was densely forested in its native state prior to intensive logging that occurred in the early 1900s. However,!sig- nif icant groupings of vegetation are located on the site, including Douglas Fir, Big Leaf Maple, Western Hemlock, Western Red Cedar, Alder, as the dominant species of the native coniferous /broadleaf mixed forest. The site appears to have undergone additional clearing since the original logging activities and, at the present time, a number of firs of the 8- to 14 -inch category andsome larger Big Leaf Maples are scattered throughout the site - in some cases in significant stands. -The understory in- cludes grass, blackberries, salal, Oregon grape and other shrubs and grasses native to the mixed forest. The major groupings of trees are shown on the site inventory and site plan as well as the topographic survey (Figuresi4, 6 and 8). 50 The site is typical of many of the plateau regions above. the Green River Valley, and a site visitation by a land scape architect. did not find any rare or endangered species occurring within the proposed development site. b. Impacts Sane portions of the site will be extensively cleared for development of the project, namely the western portions with those areas shown on the site plan (Figure 8) to be retained. These areas contain large Firs and Maples. The vegetation around the level areas of the two ponds will be retained as a part of those retention ponds. The project proponents, the architect, landscape architect and other consultants have expressed intent to preserve large trees within the development to the maximum extent possible. It might be noted that from the inventories and visual surveys of the site, much of the significant vegetation viewed from below the site on I -405 and other areas occurs in the steep -slope areas, where it will be retained. Clearing and grading requirements for construction will result in removal of vegetation from some areas, ranging from 40 to 80 per cent of isolated areas. Diversity of natural floral species can be expected to be reduced as a result of such a substantial reduction in the quantity of natural vegetation. c. Mitigating Measures Minimal and selective vegetation removal should be encour- aged particularly northerly of the ridge line, where the most significant area of natural vegetation presently occurs, as well as those areas around the drainage ponds. Replanting and landscape requirements should use native species and compatible ornamental varieties. Additional inventorying of vegetation should occur, at the time of surveying for various buildings. Consideration should 51 then be given to slightly altering the orientation or siting of buildings, parking, walkways and other devel- opment in order to save significant groupings of trees. Major buffer areas along the ridge line, in the drainage areas and on the steep slopes should be preserved in their natural state, guaranteeed by covenants. . Fauna a. Existing Conditions The existing character of the undeveloped site offers limited habitat for large animals in the heavily urbanized area. However, rodents, such as mountain beaver, hare, mice, shrews and moles occur on the site. The drainage channel and bordering vegetation may attract some species such as .racoon from adjacent wetland areas. In addition songbirds and some upland game birds such as quai frequent the site. No unique, threatened or endangered wildlife species are known to occur in the project area; however, encroaching suburban development is limiting the available habitat for resident species, particularly large mammals or game birds. No fish are known to occur in the drainage channel nearby due to its intermittent flows and blockages at some downstream locations. b. .Impacts Substantial site clearing and the introduction of a large 1 human population will have the most significant impact particularly on the southerly portion of the property. Displaced wildlife may try to relocate in adjacent(for- ested areas or the valley areas nearby. However, since incremental development throughout the area is reducing available wildlife habitat, adjacent areas can be con- sidered to be at their carrying capacities for wildlife. The result will be a net reduction in species diversity and the number of individuals of each species that will be present in the area.. 52 c, Mitigation Preservation of the steep slope, watercourse areas and pond areas should substantially preserve this habitat for species. The restoration of some vegetation in the area in the form of landscaping would provide a future habitat for those species which are compatible with an urban environment (i.e., songbirds, squirrels,.etc.). The open space system will provide a corridor for the movement of animals between the park and open space area and other areas in the general vicinity.. 6. Noise a. Existing Conditions The site currently contributes no measurable noise to the environment. Major noise factors in the area are the two major highways and their interchange. The interchange itself is 1/4 to 1/2 mile distant, while the roadway of Interstate 405 passes within 800 feet of the southwest corner of the site. This freeway alone has peak hour volumes that should generate noise levels above 70 deci- bels (dBA) at least 10% of the time (L10). This is sup- ported by readings of sound levels above 70 dBA at the south side of the Tukwila apartments, immediately west of this site and closer to the major interchange. This noise level is at or above the level which Federal Highway Administration standards define as the maximum level acceptable in residential areas near highways. Local and Federal standards also indicate this as a level likely to cause annoyance and interfering with speech out of doors. The two houses south of the site on 62nd Avenue should be receiving average peak (L10) noise levels close to 80 dBA out of doors. b. Impacts The development will generate noise levels on and off the site due to traffic to and fran the site. The single- 53 family area, with access to the north, will generate! only a small amount of traffic noise. The Multi-family aevel- opnent, with 189 units gaining access to the south via 62nd Avenue, would raise the noise generated by traffic on that road alone by a substantial amount. A rise of 10 decibels above the existing ambient noise levels is nor - mally considered to be significant, causing annoyance. However, the potential receptor areas will already be receiving noise from the highways in excess of 70 dBA (L10), and median noise' levels (L50) substantially in excess of the 60 dBA standard. The noise level at 50 feet from 62nd Avenue, generated by this project plus the San Juan Apartments and the anticipated project to the south- east, would probably not exceed 50 dBA (L50). Its will therefore probably not be perceived above ambient {noise levels from the highway. Construction on the site will create noise peaks,11 with substantial use of heavy equipment, pneumatic tool's and some blasting to move a substantial amount of earth, hardpan clay and bedrock. Such equipment can generate noise levels of 65 to 85 dBA at 50 feet. The areas most exposed to noise impact from this site will be the Tukwila and San Juan Apartments, plus apartments under contruc- i tion along the west border of the property. Tb thelnorth is the, Tukwila Elementary School playfield, which] will receive less noise, as intensive activity will take mainly on the southerly half of the site, behind the place ridge line. Noise peaks may be reduced by up to.6 dBA for each doubling of distance from machinery, so that noise from the center of the site would be reduced by distance iby 18 dBA on adjacent properties. Earthmoving near the site perimeters will have the greatest impact. The construc- tion period is estimated to include less than three months of heavy earthmoving activity in each of the three phases Thereafter, heavy machinery noise peaks will be reduced and replaced by general construction noise and trucks. 54 c. Mitigation Construction noises will occur in phases at different locations on the site. At any one time, the majority of the potential noise receptors around the site would be a substantial distance removed from the noise generating activity. Further mitigation could be achieved by limit- ing heavy construction operations to normal working hours and by giving advance notice of sudden or exceptional noises such as blasting. 7. Light and Glare a. Existing Conditions None b. Impacts Traffic entering. and exiting the site at night could cast light upon sane nearby residences from headlights. Scan light will be visible from the residences, themselves fran areas off the site. c. Mitigaton Much on site light will not spill off the site due to topography and the vegetation being left. Proper orienta- tion of buildings and use of berms and landscaping along roads and entrances can minimize light spill off the site as well as between areas of the site itself. Parking -lot lighting should be kept downward - directed, at a low level to prevent glare. 8. Land Use In that the request is for a zoning reclassification this subject has been covered in detail in Section II -F - Rela- tionship to Existing Plans and Regulations. In addition the following conditions and impacts are reviewed. 55 a. Existing Conditions The site is vacant with no improvements; some timber exists on the site, primarily 8 to 10 inch Douglas firs. In addition some Maples and Cedars of significant size are scattered on the site. The site at present with its R-3 and R-1 12,000 zoning could theoretically support 30 to 35 single family' lots' and 44 to 58 apartments or condominiums in a series of 4 -plex buildings. The.former comprehensive plan,called for multi - family on the entire site with no density clarification (i.e. nearby properties are R -1, R-3, R -4 and RMH. (See Figures 2, 3, 3A). Apartment densities in area range as follows: i San Juan 16 acres, Tukwila - 22 acres, - Southcenter '- 26 acres, La Vista -'36 acres, .Stardust - 41 acres. ,This plan was changed in 1977 and the present map and policies described in Section II -F will guide land use decisions and rezone applications. The requested change in. terms of density is summarized in the table below. Table 1, Proposed Zoning Areas and Densities Location No. of Zoning Comprehensive Zone on Site Units Acres DU /AC Code Plan R -4 Southwest .134 6.16 22.70 43 17+ R -3 South of 32 3.15 10.20 18 7 -16 Ridge Line R-2 Northwest 18 2.23 8.07 10 - 7 -16 R -1 Northeast 10 3.19 3.14 3 -5 1 -6 The resultant site coverage with buildings is 17.8% and other impervious surfaces. 30.0% for a total of 47.8 %, site coverage. 52.2% is in open space and landscaped areas. 56 b. Impacts The 14.7 acres of undeveloped land will be committed to multifamily and single family uses, plus a 2.56 acre open space tract. The proposal would provide a range of 3.19 to 20.70 DU's /acre, averaging 13.19 units /acre. Impacts to adjacent properties include: loss of vegetation and open space, increased traffic, use of recreation and public facilities. c. Mitigation Alternative site designs and densities could reduce asso- ciated impacts. The declining densities of the Planned Unit Development approach provide a variety of housing opportunities while providing transition zones to existing adjacent development as well as within the site. The relative, impact is reduced by developing at a lower den- sity than existing on adjacent properties. 9. Natural Resources a. Existing Conditions No natural resources are on the site, other than trees, and none are being consumed. b. Impacts Wood, cement, asphalt and energy resources will be util- ized on the site. The project will not require any un- usual amount of these to be consumed on site that would not be consumed by construction on other sites, except for the consumption of fuel in the excavation and fill proce dures . c. Mitigation Reduction in size of project would reduce materials consumption. 57 10. Risk of Upset or Hazardous Conditions a. Existing Conditions None applicable. b. Impacts The required blasting of bedrock will require the use of explosives on site for a brief period. Though impacts normally only include sudden, but brief low- frequency noise peaks and vibration, there are small but inherent hazards of damage fran improper handling or blasting. c. Mitigation All possible safety procedures for explosives handling and use will be followed. B. Elements of the Social Environment 1. Population and 2. Housing a. Existing Conditions Housing in the City of Tukwila is predominantly in multi- family structures (66 %). and has shown the development pattern of "boom- and - bust" in housing development typical of apartment - construction cycles. Housing composition is summarized in the table below. Average persons per occu- pied housing unit has averaged about 2.2, closer to the average for apartments than for detached units (2.:7 to 3.0). Residents have statistically been younger, but near or above the regional average in incomes and education, again typical of an apartment area. b. Impacts The statistical housing and population impacts are :sum - marized below in Table 2. The "1978 Housing Estimate" is from the City of Tukwila Planning Department's estimate for April 1, 1978, beginning fran the 1977 Census of the City as a base. The 1978 figure has not been certified by the State of Washington. 58 Table 2 Population and Housing -- Tukwila 1977 Census 1978 Estimate Added by Project (Est. 1982) As % of 1978 Single- 5+ units/ Total family Duplex Triplex 4 -Plex Bldg. 1685 574 1693 578 22 3 48 1038 22 3 52 1038 199 10 18 32 11.5 1.7 81.8 61.5 Est. population / unitl (2.5) 3.0 3.0 2.2 Est. population added 448 30 54 70 139 12.9 2.2 300 1Per observations of similar projects. Figures assume maximum high number in order to calculate maximum impact. The maximum population impact is estimated.at 498 persons, assuming no vacancies. Actual population will probably be lower, with some vacant units. A statistical average for family size has not been established for condominium units in this area, so the figures for the single - family and duplex units were the average for owner - occupied units in the county (currently mostly in single family dwellings) and the balance at the average for renter - occupied, dwellings. Relating the proposal to the existing housing mix in Tukwila, the project is adding proportionately less to the supply of single - family housing and to large multi -unit structures. It is adding a far greater proportion to the currently low supply of two- and four -unit structures. Though the trend towards multi - family structures in Tukwila is being continued, the condominium ownerships will tend to increase the proportion of owner - occupied dwellings in,Tukwila. 59 c. Mitigation The population and housing impacts will be spread out over three'years. 3. Transportation /Circulation a. Existing Conditions (See Figures 2, 3 and 4) Area Streets The project area is touched at the northeast and southeast corner by existing developed roadway. A' right of way along the easterly .boundary in the 62nd Avenue South alignment is unopened from South 151st Street at the northeast corner and South 153rd Street at the southeast corner. South 152nd is open to a point approximately 200 feet from the west boundary line of the proposed devel- opment. At one time South 152nd Street divided the prop- erty between lots 8 and 9 but was vacated several years ago. Access to the northeast corner would be to a well - improved right of way with curbs, gutters and sidewalks that joins 65th Avenue South, carrying traffic fran.that area south to Southcenter Boulevard and north to the bal- ance of Tukwila, the Fire Station, Police Station, schools and other facilities. However, as much of this Area is single - family, this proposal limits access to this area in order to minimize impacts on that street corridor. The southeast corner, 62nd Avenue South, is an improved two - lane road of approximately 18 feet in width with 3 to 4 foot shoulders and open drainage ditches. The roadway is proposed to be developed at its southernly terminus along the last 200 to 250 feet to serve the new City Hall pre - sently under construction. South 153rd Street south of the San Juan Apartments (i.e. at the southeast corner of the project site) is an improved two -lane private road. Severe visibility problems occur at the intersection. of South 153rd and. 62nd. Avenue S. Driveway cuts to serve the subject property will consider the elevation of thisoor- • ner. Any future development of the property to the south- 60 east of that intersection, i.e. .a portion of lot 16 of Interurban Addition known as the Black and Caldwell prop- erty will be required to dedicate right-of-way and widen both 62nd Avenue S.E. and South 153rd. The development of the proposed project, if concurrent with that of the Black property and of portions of lot 11, may provide opportuni- ties for joint efforts to improve 62nd Avenue South from the conclusion of the city's improvements to South 153rd Street. Tb the west of the subject property South 152nd Street is opened to serve existing and developing apartment com- plexes in the area. The existing facility and proposed improvements have been the subject of significant con- sideration and discussion by adjacent property owners, the city and the county. This road is narrow with no curbs, gutters or sidewalks and is heavily impacted by existing development. The proposed project would have an outlet to 152nd Street; however, it would be proposed only for fire- lane access with a break -down barricade. The site planning and circulation plans call for carrying all of the multi - family dwelling units' traffic to the southeast corner where it reaches theexisting arterial ( Southcenter Boulevard) and Freeway interchanges with I -405 and I -5 by the most direct route. Transit Metro transit provides several routes linking Southcenter Boulevard, Southcenter Shopping Center and Tukwila with other valley communities such as Renton, Kent, Auburn, nearby facilities such as Seattle- Tacana International Airport and employment centers as well as downtown Seattle and east side communities such as Bellevue. Several tran- sit lines serve Southcenter, and are within walking dis- tance of the proposed project. 61 b. Impacts The proposed development is projected to generate approxi- mately 1,234 vehicular trips per day. See Appendix C. The impact on South 151rd Street from:10 family dwelling units, assuming 10 trips per household per day, would be 100 trips per day. Assuming the worst case situation of 20 per cent of the trips during a peak hour this would represent 20 trips or one every 3 minutes. Other times of the day would average 5 trips per hour or one every 12 minutes, assuming all trips occurred in a 14 hour time period. . The internal circulation system of the project will carry unit traffic through the 4 -plex area and through the more dense portions of the project to 62nd Avenue South. These traffic impacts are projected to be, at 6 ADTs per dwelling unit, to be approximately 11,134 AIYPs. This traffic as it is carried down 62nd Avenue South to Southcenter Boulevard should have a minimal impact on the carrying capacity of Southcenter Boulevard and represents a 10 percent increase on that facility. Some congestion could occur on 62nd Avenue S. and at the point where those traffic flows combine with city; hall traffic. At present the adjacent San Juan Apartment development and additional units could generate in the vicinity of 240 to 300 AIMS. Proposed developments on the Black property could generate 300 to 600 ADTs. Of those instances! some of that traffic may Choose to utilize South 153rd Street to join 65th Avenue east of those developments. Assuming 50 per cent of traffic turns each way, half of the traffic generated by those two projects would be carried on! 62nd • Avenue South. The remaining property that would be avail- able for development of a significant size is lot 11, pre- sently owned by Mr. Ehmke. The resultant development level on that site is unknown at this point; however, assuming that this property was developed at 18 to 22 62 units per acre consistent with comprehensive plan, its 6 acres would yield 108 to 132 units and in turn 648 to 792 ADTs. Assuming this entire development would gain access over 62nd Avenue S. this would result in a fairly signifi- cant impact on 62nd Avenue South. Tbtal.generated traffic of these four areas on 62nd Avenue plus two existing houses were totaled they would equal 2069 to 2396 ADT's (an 18 per cent increase on Southcenter Boulevard). Transit At present there is no formula for estimating the use of transit services by residents of •the developments or the existing developments . in the area. Other multi - family projects typically generate some demand on the services. The availability of extensive local. service as well as service to downtown Seattle is expected to attract riders from the proposed project area. Construction of shelters near the city hall to serve that facility and potential projects on the Tukwila hill including the Northward Development proposal would serve to promote greater transit usage. c. Mitigating Measures The proponent is suggesting cooperation among the four major property owners in the area to assess the impacts of proposed and existing development on 62nd Avenue South and cooperate with the city to provide improvements for. auto, pedestrian and bicycle traffic in the area. This would benefit all properties through improved traffic circula- tion and minimize traffic friction and conflicts. Resur facing and widening of the roads, installation of under- ground storm drainage, curbs, gutters and a sidewalk may be conditions of approval of all pending and future devel- opment plans in the area. Participation in.an LID may be the mechanism for approving this type of development. I f further studies show a need for improved traffic control 63 at the intersection of South 63rd and Southcenter Boule- vard, installation of those facilities may be warranted. Transit Car pooling and the use of Metro services promoted through literature in the condominiums' offices and recreational facilities could reduce peak hour and average daily traf- fic generation for the development. 4. Public Services. a. Existing Conditions Fire Protection The proposed development is in the City and would be served by the City Fire Department. Tukwila has twoifire stations, one in Andover Park which serves the industrial area and one at 59th Avenue. South and S. 147th Street. Estimated response time would be 1.0 to 2.5 minutes to the northeast corner and 2.5 to 4.0 minutes to the southeast corner of the proposed project. Fire flow at the margins of the site is currently estimated to be adequate to serve the project. Additional information will be developed following zoning review to support building permit appli- cations. Emergency medical aid vehicles are . available at the ,Tuk- wila City Hall site. Police Protection Police protection is located at the same site of the 'fire station near the old city hall. The Tukwila Police De- partment patrols and responds to emergency calls in the vicinity of the proposed project. The ratio of police officers to population in the City of Tukwila is presently at or slightly above the national average for a city of its size, in part due to the large commercial and indus- trial areas which require additional protectioniand security. 64 Schools The proposed Northward Development project is within the attendance areas of South Central School District. Tuk- wila Elementary School is contiguous to and directly north of South 144th Street. Junior and Senior High Schools are within a walking distance of 10 to 20 minutes via a free- way overpass, but students from the proposed development would be provided bus service to the junior and senior high (Source: South Central School District, Transporta- tion Services, personal communication by telephone con- versation). The capacities and present enrollment of the schools leaves some spaces in each which would adequately handle the projected enrollment levels of this project. Southgate Elementary School is scheduled for closure this year due to falling enrollment. Tbtal district elementary enrollment for the 1978 -79 school year is estimated at 827. This will be handled by the three remaining elemen- tary schools, with a combined official capacity of 1,025. "Comfortable" capacity, reserving roams for music and remedial reading, is 875. The proposal is not anticipated to be accommodated in Tukwila Elementary with no bussing required. School enrollment has been consistently dropping in the district, due to changes in resident characteristics in the area, and the static housing supply. The annual enrollment in 1979 -80 is expected to equal the previous year, and a climb in enrollment is expected in 1981 -82, when enrollment may be expected to be generated by this project. "Comfortable" capacity is expected to be reached in the 1983 -84 school year (School District estimates). Parks and Recreation Parks, recreation and open space areas in Tukwila,, in particular around the Tukwila Hill area, include 5.3 acres at Tukwila Park adjacent to 65th Avenue .South, a 52 acre regional King County park along the Green River near I;405 and Foster Golf Course along Green River near Interurban Avenue. School playgrounds provide additional active recreational area and the undeveloped areas in portions of the city provide passive open space areas. However, with- in the city limits of Tukwila. there are only 6.3 acres in city ownership used for park or recreational purposes, somewhat limited for a city of this size. Additional open space and recreational facilities would compliment that limited city resource. Maintenance Roads and storm drainage systems in the vicinity of the project area are presently maintained by the city of Tuk- wila. The city and Metro (the Municipality of Metropoli- tan Seattle) maintain sanitary sewer systems. The water system in the area is maintained by the city and utilizes City of Seattle water. b. Impacts Fire Protection Approximately 250 fire and aid calls per year are 'gen- erated per 1,000 residents in the Tukwila area. Total population of the proposed development is projected to be no greater than 450 persons. Therefore in a worst case situation approximately 120 fire and emergency calls per year may occur from the project area. In fact, fire calls will probably be much lower than average in the new build- ings, with required fire safety devices. In addition the average reflects a very high incidence of non - residential fires. Service for the development is not expected to have any adverse impact on existing manpower or equipment. 66 Police Protection Residential uses have a moderate impact on police, pro- tective services in the form of burglaries and emergen- cies. Non- emergency calls -are perhaps the most time - consuming requirement of multiple - family developments. The circulation and street configuration can both posi- tively and adversely affect police emergency response time. Discussions with the Police Chief indicate that through circulation is desirable in order to serve emer- gency vehicles and promote quick response time. However, through circulation'can provide the adverse element of allowing burglars in adjacent property more direct and unimpeded escape routes when pursued by police personnel. This proposed development is not expected to directly result in the requirement for additional police personnel or equipment. . However, the cumulative effects of in- creased development on this hillside may necessitate addi- tional expenditures in the.future. Schools Due to the phasing of the proposed project, maximum school impacts are not expected until the 1981 -82 school year, when school planning presently anticipates growth. At a "worst case" estimate, this proposal could generate 50 elementary school students, bringing the elementary schools to their "comfortable" capacity, as estimated by the district. Other developments could take elementary enrollments higher. The District's strategy at that time could include reopening Southgate Elementary, expanding another school or going beyond "comfortable" capacity. The predictions for secondary - school enrollments were not carried beyond cohort - survival projections. It is assumed that up to 50 students could be added, with some impact on the capacity of those schools. 67 Parks and Recreation Residents of the proposed development could be expected to utilize the park and recreational facilities in the city and in the Green River valley, playgrounds, and Ito a lesser extent the golf course, fishing opportunities in the Green River Valley and nearby lakes as well as other community facilities of adjacent communities. Maintenance The proposed development would have private roads and storm drainage facilities for which the owner of the de- velopment would have maintenance responsibility. Repair of surfaces, cleaning of pollution control devices, main- tenance of storm drainage and utilities on site would be required of the developer and future have owners. All public roads and utilities in the area would require maintenance by the City with associated rise in personnel and material costs. c. Mitigating Measures Police Protection The police department should be provided with a copy of the final approved development plan locating new street addresses in the project area. Fire Protection All fire code and building code requirements will.bejmet. Future site plan approval should consider access to indi- vidual areas of the project. Linking of water mains in the area sane of which are presently dead ends (i.e. 152nd Street) should improve fire flows. If future studies of fire flows warrant additional mitigating measures1 the interior common areas of buildings could have sprinklers. All units are proposed to have smoke.alarms. Parks and Recreation The development proposal includes 2.56 acres of open space facilities with an additional recreational area including a building, two tennis courts, a swimming pool and large areas of trees and open space are scattered throughout the site. The trail system would provide for jogging, walking and passive recreation, mitigating the need for these facilities in adjacent areas. Maintenance Stringent storm drainage design requirements could reduce maintenance. Regular maintenance of the privately owned drainage facilities could reduce maintenance required for public portions of the system. 5. Utilities a. Existing Conditions Energy Puget Sound Power and Light would serve the proposed de- velopment with electrical energy. The proposed condomin- ium units would be "all electric" and are estimated to use approximately 2,000 kWH of electricity per unit per month (conversations with Puget Power). Use of natural gas may be considered for heating the swimming pool. The gas mains, according to phone conversations with Washington Natural Gas, are available at the northeast corner of the property and can be extended to the southeast corner in developed rights of way. Communications The project area is served by Pacific Northwest Bell and hookups are available at the southwest and northwest corners of the property. 69 Water The city of Tukwila provides water service for the prop- erty as shown in Figure 12. .Water is available at Ithe northeast' corner through an existing 8 -inch main located in the 152nd street right of way. A 6 -indi water main is also available, presently serving the Tukwila Apartments at the southwest corner of the site. The Public Works Department suggests linking these various water mains to provide continuous loops, better water service and better pressure for fire - fighting purposes. Sewer The City of Tukwila and Metro provide sanitary sewers) in the vicinity of the project. An existing 8 -inch sanitary sewer is at the northeast corner. An existing 8 -inch line serves the new City Hall property on 62nd Avenue South. The latter line would be required to be extended as a part of 62nd Avenue South improvements, as shown in the sani- tary sewer system, Figure 13. Any sewer extension wouldlbe through an LID or Developers extension agreement and sized to fit engineering requirements (i.e. 8" is preliminary). This proposed sewer improvement would serve three major . properties in the area. Storm Sewer Ab publicly owned storm drainage system exists in the project area at the present time. Runoff from major por- tions of the site travels to the east down.an existing drainage Channel past the new ,city hall and under South - center Parkway to a point where it joins an existing stream bed that flows easterly along I -405 into the Green River. Peak storm water flows for the 10 year storm will bee detained onsite. These flows will be released to the existing drainage channel. In addition sane peak flows from the project could be taken care of in an improved. drainage system along the improved 62nd Avenue South 70 / / ��_ / \� //'//' \ / /' | . / f/JPMS law MAIM me6 xwwmS 71000 6ALIONS ` \ u����== - • --- -- -- -- ----/| ' . ~ '43 • �� • ^.^ ` ` ` '^° �! ```- _ '^, `~-w•- ' - •.���- .� • / ~` "°~^^~~'— / --~^'~°^ ' «^u�umvwmrmw, ' � / fflq.ri ON Or: 0 '00 100 ( ~~/ 7 l FIGURE 13 SANITARY SEWER SYSTEM 47'' ST 1\;i1TE .7677/7(/ • •,\\\ ,\ EIM(G S' SAN SEWER/kW Niel mita AND OVUM J re &int. ,netri astir &swat - xivrAL i • ( • L.; PCCR•RLEXE1 AND APARTMENTS 166 UNITS AVERAGE DAV 4000 GAL ;wow s411 JEW --. AWN (ID SE MAT Of (FPO mr. s IMPROVENENI31 _ 45, <5v•• 40. ASSOCIATES 4 s.Aro'sr \\\ 1 1 1 1 1 1 ED 0 \ARMY/ OF: e3, 7WP 2314 pi( 1 t I .___} a ,.t " ...... , , nuove4 on, 'au / n*VOLP ODXSIRICTON) / / / .../-/ __..., eS ------- ' tA114N6-8fSA SEWER AWN 71 a 711-004, right - of-way as a secondary system to the main drainage channel. b. Impacts Assuming that the proposed dwelling units will be all electric and will require approximately 2,000 kwh of electricity per month (average), implementation of the project would result in the increase in monthly electrical requirements for the site approximately 398,000 kwh at full development. According to Puget Sound Power and Light, they have adequate energy resources and equipment in the present service area and' would expand its local services as necessary to accommodate future growth. Communications Telephone communication service for this development is estimated to require 254 cable pairs. According to Pacific Northwest Bell, this can be accommodated within existing systems. Water Implementation of the proposal will require construction of water mains through the site linking existing facili- ties at three corners and the west side of the site. Water consumption within the project area will increase usage in the area approximately 30,000 gallons per day. The increased requirements for water services is not expected to have an adverse impact on existing water sup- ply or the proposed system through the site. Sewer The proposed development could be expected to generate approximately 20,000 gallons of sewer per day (see Appendix C). This increase in sewage flow from the project area is not expected to have an adverse impact on sanitary sewer in the vicinity according to the public works department. 72 Storm Drainage Drainage within the proposed development would be col- lected in surface collection systems including retention areas and released at a slower rate into existing drainage channels or in improved storm drainage along. 62nd Avenue South. c. Mitigating Measures Energy Discussions with the architect indicate that energy con- servation measures (as well as noise limiting measures) such as weather stripping, wall ceiling and floor insula- tion and insulated windows will be provided in the pro- posed dwelling units to reduce heat loss. Common wall construction is proposed for most of the units and will reduce energy requirements for residential heating. Water and Sewer The installation of water saving devices in new dwelling units could reduce water consumption and sewerage flows. 6. Aesthetics a. Existing Conditions The natural condition of the site with extensive .tree cover and other vegetation provides a visual amenity to the Southcenter area, adjacent properties and the entire south face of Tukwila Hill. A small, shallow, year -round stream meanders through a portion of the site and along its easterly perimeter. The topography of the site, its location near a school and other factors make it one of the more desirable undeveloped sites in Tukwila. Many portions of properties around the site particularly on the west and south have been almost totally cleared of vegetation making this site an unusual one with only the site to the southeast and scene to the northeast in similar condition. 73 � UMW NM S - - - - 010 230 110 190 170 150 250 210 190 170 150 EAST - WEST CROSS SECTION 250 -.- 210 190 170 150 . EAST - WEST CROSS SECTION 8 ,NORTH -SOUTH CROSS SECTION FIGURE 14 LDNOT - FRONT ELIEVLAVTOON I/4"= I'-O" UNOT A • ROOM BILISVATOON I/4"• I'-O' II malunidammisMits TOP OF PLATE UPPER LEVEL GRADE 111 III II [III II MNn104 B • FRONT ELEVATION I /4° ' 1111111 111111 LOWER LEVEL LIVING ROOM MNDY B • FR A t V AV0 ®Ir1►1 LIJNOT B • V ATU Intel I /4 I/4" FIGURE 15 -B • • D -ST a inoI3 *� B 11 M ®�® �1 ®OA�lA M BOOM IIinse MtOcJ , 0'd •vA aivpv a ® ®=1I® IN1CD J Vw> ilMI BOOB iinTtlln,4 9gN10'iln4 11Nn • 0. ilYM109 10'11 -,QA a Ervave ® ®� NCO 0JLw 1� A,fnl ®tea -nemacoA.A. i I��� CLl- ■ linilliHIIIHi unuuuuui ■ ■Ing En ■ iiiii • �� ; 1, b. Impacts Approximately 50 percent of the site would be developed with condominiums, parking driveways, trails and other facilities. It would have an impact on views to the site, particularly on views from Southcenter Boulevard and properties to the south, west and east. A more detailed analysis of this impact is contained in the graphics that follow this section. c. Mitigating Measures Retention of natural vegetation to the maximum extent possible and generous landscaping can reduce the impact of hard surfaces (roads, fences, buildings) and preserve a certain degree of the forest character of the site. Build- ing designs are proposed that take advantage of the slop- ing of terrain on the site to avoid the repetition of rectangular building facades. The large buildings have been turned at an angle to appear less massive from prop- erties to the west, south and east. The ridge line and existing vegetation have been used to obscure the common- wall developments from the northwest, north, and north- east. The architect has utilized existing topography and major groupings of vegetation wherever possible to nestle the buildings into the site. The four -plex and duplex town- house units will be incorporated into existing vegetation using exterior wood siding with natural earth tones to be compatible with the site. Larger buildings will have scene wood details and some stucco finishing. There will be extensive landscaping, rockeries and other facilities to provide a natural transition for the existing topography. In addition, screening easements, retention of the vege- tation through restrictive covenants and the use of densely planted vegetation perimeters will be provided between different use areas proposed for the site. 78 7. Archaeological/Historical Resources a. Existing Conditions A'review of City planning. documents, County planning docu- ments and discussions with State agencies uncovered no known archaeological or historical resources in the pro- posed project area. 7 IV. REMAINING ADVERSE IMPACTS THAT CANNOT BE MITIGATED A. Modification of the topography will take place on site to accommodate buildings and roads, requiring movement of a large ,quantity of soils. B. Storm water runoff will increase in quantity, except that peak flows will be lowered by detection facilities. Some increase in pollutants in the runoff will take place, including oils and grease, heavy metals, sediment and nutrients. C. Animal habitat will be removed as vegetation is removed from a large portion of the site. Only species tolerant of human activities will remain. Occupants driven from the site will largely perish. D. Residential uses will be established in an area subject to high peak levels of noise. E. The 14.7 -acre site will be committed to urban residential land use, at a greater density than under the existing. F. An increase in the potential population of the site, as a net effect of the rezone, of an estimated 230 persons; an absolute increase, due to the projected construction; of up to 450 persons, over a three -year period. G. Traffic will be substantially increased on 62nd Avenue South, from the Southeast corner of the site to Southcenter Boulevard, and increased by 10 per cent on Southcenter Boulevard, east of the overpass to Southcenter. H. There will be a general increase in demand for public services, in proportion to the rise in population anticipated (about 15 per cent). 80 V. ALTERNATIVES TO THE PROPOSAL The following alternatives are summarized on page 13. These alterna- tives are ones that are readily available under existing or proposed zoning and are modifications of the proposal developed by Northward that would satisfy the general goals and intent of their proposal. 1. Use of the site for single- family (R -1) and fourplex (R- 3),under existing zoning. As shown in Figure 3 half of lot 10 is presently zoned R -3, which would allow for fourplexes with the balance of the property being R-1, 12,000 square foot lots. The zoning was developed at the time the city was incorporated and carried on the site in the absence of any zoning request on the property. The former compre- hensive plan showed this entire area for apartments without any . density clarification. Under the former comprehensive 'plan prop- erties contiguous to and west of the subject property were rezoned to R -4 and RMH. Properties to the southeast were rezoned to R -4. At present there is an application on the property to the south to change the zoning fran R -3 to R -4. The revised comprehensive plan calls for a break in densities and uses over the site ranging from high density residential (M/F) on the southwest, medium density residential (M/F) in the middle portions and low density residen- tial (S /F) on the northeast corner. Preliminary studies conducted by site planners for the Tukwila Associates group indicated that single- family development of the site would be possible, however, extensive costs would be asso- ciated in terms of providing roads and access and the impacts on the site might be much more significant than that of clustered housing with open space areas provided for in steep slope areas, drainage areas and difficult soil areas. Disamenities such as noise, location near very dense, existing apartment complexes made the decision to utilize the property for single family an unat- tractive one to the property owners and potential users who would develop the property. 81 2. Maximum utilization of the property south and west of the ridge line for R -4 zoning, R -3 along the ridge line, the balance of the site in R -2 and open space. This alternative has been presented as part of a previous request to the Planning Commission and Council via waiver frcan provisions of Resolution 489 (interim land -use regulations). Under this proposal the southwest portion of the property would be used for an R -4 apartment complex at a density of approximately 28, to 30 units per acre for 6 to 6 -1/2 acres. The R -3 zoning would provide for townhouse condominiums at 16 to 20 units per acre over 6 to 6 -1/2 acres. Duplex and triplex townhouses would be developed at 8 to 10 units per acre; with approximately 2 acres of the balance of the property in open space. The proposal is summarized in the table below. SUMMARY OF USES AND DENSITIES Area Housing Type Density /Acre Acres Total Units 1 Apartments /Zbwnhouses 30 6.0 -6.5 180 - 195 2 Zbwnhouses /Condominiums 16 - 20 6.0 -6.5 108 - 130 3 Duplex & Triplex Townhouses 8 - 10 2.2 -3.2 16 - 32 304 - 356 It should be noted that this is a modification from previous con- siderations on .this property by Tukwila Associates, original owners. The previous application had suggested 28 to 30 units per acre or a density approaching 450.total units. The modified ap- plication discussed a range. of 24 to 29 units per acre or 304 to 356 units. At the time of this application, the Comprehensive Plan had not been adopted and the City was acting under Resolution 489. At that time some of the densities proposed were felt to be inconsistent with the emerging comprehensive .plan. The applica- tion was denied with direction given to modify the application following the adoption of the Comprehensive Plan. 82 3. Utilization of existing zoning classifications on individual; lots as follows: R -2 on Lot 8; R -3 on Lot -9 and R -4 on Lot 10. The splitting of these three formerly platted areas, approximately 5 acres in each lot, would provide for the application of a separ- ate zoning district or classification on each lot. A transition zone could be-established on each property from adjacent proper- ties to the north and south. The zoning classification 'would provide for duplex uses on the entire portion of Lot 8, triplexes on Lot 9 and more dense apartment units on Lot 10. The resulting densities would be 0 to 6 units (low- density residential) on Lot 8', 7 to 16 units (medium - density residential) on Lot 9 and 17+ units per acre (high density residential) on Lot 10. Under !maxi- mum utilization this would provide for 30 units on Lot 8; 80 units on Lot 9 and 85 to. 140 units on Lot 10-.-a total range of 195 to 250 units under this type of proposal. This assumes a limitation' on the R -4 consistent with the comprehensive plan guidelines:of 28 units. per acre rather than the zoning code limitation of 43 ;units per acre. If R -4 under the zoning code was utilized for Lot 10, the upper range of units under this proposal would be 325 units.. 4. All uses as proposed except that the single - family area would be retained as open space either by covenant to keep as a natural area or deeded in fee to the City as passive open space area with a potential site for a water reservoir facility. This alternative has been discussed as part of the comprehensive planning process and letters from the original property owners conveyed to the City indicating that this was a viable alternative to them. Subsequent conversations with various members of the City staff have indicated a strong concern at the City for pro- viding single- family sites. A review of the land use inventory document developed as part of the comprehensive planning process indicated that there have been only 12 single - family homes built in the area in the last 11 years up to 1976. The proposedladdi- tional 10 single - family sites would match the single - family 83 development in Tukwila for the past 8 or 9 years. The area pro- posed to be open space would be an extension of that 2.6 acres of open space ..along the ridge line. In that this area is highly suitable for low density development, either clustered duplex townhouses or single- family, the proposal to provide single - family in this area would 1) provide additional housing stock of a single- family nature in Tukwila, 2) provide a well- defined transi- tion zone from the existing R -1 -9.6 to the north and northeast, and 3) help to define what would occur on the property to the east, this appears to be the more logical alternative. However, the alternative of leaving this area an open space remains a viable one and should be determined as part of . policy decision by the Planning Commission and City Council. .5. Modify size and configuration of proposed use zones. A myriad of alternatives,, whereby minor modifications of the con- figurations of the proposed site plan could be undertaken,. The proponents' architect, site planners and others involved in the project have undertaken numerous studies and discussions of alter - natives.and analysis of feasible and viable projects. These dis- cussions have also been clarified and directed by numerous discus- sions with the City staff. Minor modifications of the existing zoning proposals could be made as a part of the hearing process. However, at this time proposed action appears to be responsive to the natural system, in response to the comprehensive plan map and policies and consistent with feasibility studies done for various developments on the site. 6. No action. This alternative would leave the site in its undeveloped character awaiting utilization of adjacent properties for residential uses of various densities from RMH (high density apartments) to de- tached single - family under R -1. Feasibility studies have shown that other than minor portions of the site being used for single - family it is highly unlikely that the property would be developed 84 in the short term absent any rezoninig action. The proponent does not have access to alternative sites and given a decision not to approve this zoning application or some modification thereof, would withdraw from the project. The previous fee owners, ;under contract purchase with the proponent, would retain the property until zoning action could be clarified. Impacts of the Alternatives - The impacts associated with each alternative would mainly relate to density, number of people, traffic, etc. In addition the amount of site coverage, vegetation loss, runoff, topography change andiother environmental factors impact would vary based on which alternative was considered. Alternative 1 - less open space would be retained and more topography change for roads and side development probably 'would occur. Alternatives 2 & 3 all impacts associated with increased densities and site coverage would occur. The increase of 50 to 90% in densities would result in less open space, larger buildings, greater traffic flows, increased public services, etc. Alternative 4 - minor change in impacts due to ten less single family houses; more open space, increased costs to City to maintain open space area, and loss of tax base. Alternative 5 - minor changes associated with revised densities. Alternative 6 - no primary impacts; secondary impacts include land speculation, increased future building costs, loss of opportunities to improve utilities and circulation in the area. 85 VI. THE RELATIONSHIP BETWEEEN LOCAL SHOD USES OF MAN' ENVIRONMENT AND MAINTENANCE AND ENHANCEMENT OF LONG -JTEi M PRODUCTIVITY The site would be irretrievably committed to urban development, in contrast to alternative housing or open space uses. This is countered by the fact that the site is surrounded on 2 -1/2 sides by apartments, 1/2 side by single family and potential single family and 1 side by recreational uses and is in a municipality with utilities and access on most sides. Urban growth will continue on the Tukwila Hill and the development of the site can provide a new form of site planning and design for the area while preserving some open space and being comple- mentary to the goals and policies of the city. The commitment of this site will decrease the likelihood of pressure for more peripheral development on agricultural land or other open space. VII. IRREVERSIBLE OR IRRETREVABLE COMMITMENTS OF RESOURCES The alteration from wooded hillside to urban residential uses is for all practical purposes irreversible. The development of this site will consume energy throughout the building phase. The placement of streets, sewers and other utility lines and the preliminary develop- ment of residential units will involve the consumption of concrete, metals and wood resources which will be effectively lost for other use. The infilling of the urban fabric here will decrease use of resources for maintenance over time by being integrated into an exist- ing infrastructure near shopping and employment and by decreasing pressure for development on the peripheral areas of existing urban development. 86 APPENDICES A. Soils and Geology - Consultant Report B. Hydrology and Utilities - Consultant Report C. Calculations for Analysis of Impact D. Project Statistics E. Miscellaneous Resource Data and Maps F. Suggested Conditions G. References 87 APPENDIX A SOILS AND GEOLOGY APPENDIX A [30X 126 1- 10E1ART, WASHINGTON 98025 TEL.: AREA 206 - 682 -6942 I ell E 91 E1RRTH SENENEE January 17, 1977 Robert W. Thorpe and Associates 3050 Island Crest Way Mercer Island, Washington 98040 Dear Mr. Thorpe: You asked me to make a cursory investigation of the soil conditions of a 15 -acre parcel in Tukwila. The site is under consideration, for waiver and rezone. It is, roughly bounded by extensions of South 151st and South 153rd Streets and 59th and 62nd Avenues South. Elevation d.iff'een_tia]- is about 60 or 70 ft with the lowest terrain near the •southeast corner and the-highest along part of the west property line. Surface drainage is good; although; because of human interference, water is pond.ed at nearby locations Off- the property. - • At present, the entire tract is wooded and without improvements. As. presently envisioned, future improvements would be confined to the southeastern one - third. or so of area. Those iaprovenents would con -= sist of 450 to 500 multiple- family units, although. • the number does significantly affect. findings' or con- clusions expressed herein. Prior to actual development, it will be necessary to explore the subsurface conditions in detail, either,by test pits or borings. Information in this letter was developed from a ground reconnaissance and a review of relevant geologic publications for that area. Shallow soils across the area to be developed consist of glacial till, a dense mixture of silt, sand, and Page 2 January 17, 1977 .Robert W. Thorpe and Associates gravel. It is weathered in the •upper two or three feet. Except in the upper few feet which have been weakened by weather and root action, sliding is uncom- mon in till; and no signs of past sliding were noted. Exposures off the property to the south and southwest indicate that the till grades downward into a massive unit of relatively cleaner sand and gravel, also of glacial origin. A small outcropr'•ing.of Andesitic intrusive bedrock is • exposed at the southeast property corner. Soil inimedi -. ately adjacent to the rock is of residual origin. As a practical matter, only the glacial soil will be of much relevance to development. No surface indications of adverse drainage conditions or seepage were noted. Except for possible localized horizons of perched saturation, true groundwater is no doubt well below the lowest property elevation. So far as the intended improvements are concerned, the most restrictive soil- related factors will be the moisture sensitivity of the till and slope stability of any fills which aright be placed. To minimize those- potential problems, earthwork should be kept to a minimum, and it should be attempted only during the dry season. By virtue of its cohesion and gravel content, till is not a highly erosive soil, although its impervious nature will cause greater runoff than 'from most other native soils.- Temporary sedimentation ponds.will be necessary during construction. Storm water runoff will be regulated after construction; the • effects of runoff will diminish over about a two -year period while the new flora is establishing itself. Should City personnel or any other concerned parties have any questions about this matter, please encourage taem to give me a call. JNE : a1e1 Yours very • .`.James N. Eaton APPENDIX B HYDROLOGY AND UTILITIES Page Two Mr. Robert Thorpe catch basins and then be conveyed to the existing,drainage swale at the east boundary. As a result peak flow rates will increase in the swale. However at points A and B as shown on the Existing Drainage map, the peak 10 -year return interval flows should increase by only 30% and 20 %, respectively (from 7.7 cfs to 10.1 cfs at A and from 9.9 cfs to 12.1 cfs at B). Due to the relatively steep channel slopes the existing capa- city of the downstream system should be adequate to accommodate this flow rate increase. Because of the more intensive proposed development of the south portion of the site, stormwater detention facilities will be provided to limit the 10 -year peak discharge to the south to approximately the existing 1.2 cfs 10 -year peak flow rate. Discharge from these facilities will probably be made into a storm sewer line which should be built at 62nd Avenue South in conjunction with improvement of that street to facilitate this and neighboring developments. Such a storm sewer would then discharge into the I -405 system at Southcenter Boulevard. The depression along the west boundary will probably be devel- oped as a shallow pond for use as an amenity to the project. However runoff from a portion of the area currently tributary to this depression may be routed into the detention facilities at the south portion of the site. Water System City of Tukwila watermains currently exist at or near all four corners of the site. The supply source of all of these mains is a 16 -inch diameter City of Seattle watermain.' Therefore the esitmated average daily residential consumption for the site of 74,625 gallons ,(based upon 199 units, 2.5 occupants per unit, and 150 gallons per day per occupant) is not expected to adversely affect water supply to other City of Tukwila users. Looping of some or all of the existing systems may be required for provision of adequate fire flows to the upper elevations of the site. Such looping would-also benefit nearby properties by increasing available fire flows in the existing mains. Sanitary Sewer System Sanitary sewage generated by the proposed development will drain into two different sewer mains. The main at the intersection of 62nd Avenue South and South 151st Street will receive sewage from the proposed single family and duplex areas of the site. The . average daily sewage discharge from this area is estimated to be 7000 gallons (based upon 28 units, 2.5 occupants per unit, and 100 gallons per day per occupant). Page Three Mr. Robert Thorpe Sewage from the four -plex and condominium areas will gravity to the south. This will necessitate extension'of the existing sewer main on 62nd Avenue South up to.the Southeast corner of the project. Average daily discharge from this portion of the development is estimated to be 42,750 gallons (based upon 171 units, 2.5 occupants per unit,_and 100 gallons.per day per occupant). This additional sewage is not. expected to create .sewage flow capacity porblems in existing downstream mains. Sincerely, TRIAD ASSOCIATES, INC. David L. Halinen, Project Manager DLH:cg APPENDIX C Calculations for Analysis of Impact Trip Generation Proposed Units 10 single family houses 18 duplex townhouse condos 32 fourplexes 139 condominiums Po latio 2 pu n/Housing ADT's/Jnit1 10 6 6 6 Average Daily Traffic 100 108 192 834 1,234 Total Single - family Duplex 1977 Census 1978 Census 1965 574 22 1693 578 22 Added by Project (Est. 1982) 199 10 18 As % of 1978 11.8 1.7 81.8 Est. population /unit (2.5) 3.0 3.0 Est. population added 498 30 54 Triplex 3 3 5+ units/ 4 -Plex Bldg. 48 1038 52 1038 32 139 61.5 13.4 2.2 2,.2 70 306 Projected ...Population Units 189 condominiums 2.2 416 10 single family 3.0 30 446 (say 450) 'Institute of Transportation Engineers, 1976. 2City of Tukwila census data. Projected Student Population - School Ages 60 -100 students 30 -50 50% elementary 30 -50 50% junior /senior high Water Usage . Estimated to be approximately 150 gallons per day per resident.3 Sewage Flow Estimated to be approximately 100 gallons per day per resident. Projected Resident Population: 450 persons x 100 gpd = 45,000 gpd Residential Electrical Requirements Estimated on the basis of approximately 2,000 kwh per unit per month for all - electric units. (Puget Power - phone conversation). Proposed: 199 units x 2,000 kwh /unit /month = 398,000 kwh /month Residential Communications Requirements Estimated on the basis of 1.25 cable pairs per multifamily unit and 1.75 per single family unit (Pacific Northwest Bell, March, 1978). Proposed: 189 units x 1.25 cable pairs /unit = 236 cable pairs 10 units x,1.75 cable pairs /unit = 18 cable pairs 'Total 254 3Sources: Survey by R. W. Thorpe & Associates and engineering firms (February 1978), Triad Associates. APPENDIX D PROJECT STATISTICS LOCATION: CITY OF TUKWILA CODES: TUKWILA ZONING ORDINANCE AND UBC 1973 EDITION SEISMIC ZONE: III FIRE ZONE: III OCCUPANCY: H- MULTI - FAMILY CONSTRUCTION TYPE: V -N, & V-ONE HOUR IN R -4 ZONE EXISTING ZONING: R -1 PROPOSED ZONING: ZONE R -4 R -3 R-2 R -1 (9,600) TOTAL SITE AREA SITE COVERAGE: MULTI- FAMILY SINGLE FAMILY TOTAL AREA 268,615 S.F. 137,308 S.F. 97,101 S.F. 138,753'S.F. 641,777 S.F. PAVING COVERAGE: ROADS, DRIVEWAYS, &PARKING AREAS WALKS & PATHS POOL & PATIO, TENNIS COURT OPEN AREAS ACREAGE 6.16, 3.15 2.23 3.19 14.73 ACRES 99,025 S.F. 15,000 S.F. (APPRX.) 169,000 S.F. 14,720 S.F. 2,700 S.F. 7,200 S.F. 193,620 S.F. 334,132 S.F. GREENBELT AREAS 111,400 S.F. 2.56 ACRES (NATURAL VEGETATION RETENTION) UNIT STATISTICS ZONE R -1 R-2 .R -3 • R -4 R -4 R -4 R -4 UNIT TYPES SINGLE FAMILY A DUPLEX TOWNHOUSES B 4 -PLEX TOWNHOUSES B TOWNHOUSES C 2 -BR. FLAT D 2 -BR. FLAT E 2 -BR. FLAT 15.5% 2.3% 17.8% 30.0% 52.2% SQ. FOOTAGE UNDETERMINED 1,502 S.F. 1,231 S.F. 1,231 S.F. 1,077 S.F. 1,074 S.F. 995 S.F. D.U. /ACRE 22.70 10.20 8.07 3.14 NUMBER 10 18 32 '6 48 28 57 199 1 BUILDING AREA CALCULATIONS APPENDIX E MISCELLANEOUS RESOURCE DATA AND MAPS E APPENDIX E it al RANGE 4 EAST RANGE 5 EAST CITY OF TUKWILA ZONING LEGEND R•4 RESIDENTIAL• AGRICULTURAL R•1.7.2 1 FAMILY RESIDENCE R•1.9.6 1 FAMILY RESIDENCE R•1.12.0 1 FAMILY RESIDENCE R•2.8.4 2 FAMILY RESIDENCE R•3 3 FAMILY RESIDENCE R•3.60 3or4 FAMILY RESIDENCE R•4 LOW APARTMENTS RMH MULT. RESIDENCE HIGH DENS. PF PUBLIC FACILITY C•1 NEIGHBORHOOD RETAIL C•2 LOCAL RETAIL CPR PLAN'D BUS. CENTER REGIONAL CM INDUSTRIAL PARK M•1 LIGHT INDUSTRY M•2 HEAVY INDUSTRY 44-1 CITY UNIT, Sm MOO IWO 2300 300115. £ITY.:OFTTUKWILA PLANNING DEPARTMENT MAY 1975 :TUKWILAWASHINGTON•REVISIONSz • II413 23 -:-'; j 5 cs1 22 24 12 E z 25 1...otaz} .1.•.% Zi 14 I I I ■ . °II 16 14911S . Bo '.,14.4:33 27 5....;.1 r j : • 1 ',V 1 /0 .1 i 75 1 30 ....../ 18?. "C 14 9TH'Ar S ( r ‘14 9 TY wscp .1' \ a• \ A \ \ . 0 22 FIGURE 16 ACCESS & CIRCULATION ALTERNATIVES 1111-111-11 Primary Access I MINE NS I Alternatives 0 7 ei 61 /4 ZO2 c) 1 I') r-- NI, I ,1.-„•,... • ,..iu.N. ■ ,C.,. mg,'" -9-- I ' I= 17 (V 1 1 i -r S A 4$087 S 80 13310 153) iS 15 APPENDIX F PARK PLACE REZONE SUGGESTED CONDITIONS FOR REVIEW OF REZONE APPLICATION Lots 8, 9 & 10 - Interurban Addition 1. That densities be limited to those shown in Table 3 of the Draft Environmental Impact Statement with the total number of units not to exceed 199. 2. That the site plan for 14.7 acre parcel maintain over 40% of the area in open space, landscaping and natural areas. 3. That buffer zones of natural vegetation of a minimum of 40 feet be preserved on the north and east boundaries of the property. 4. That the applicant participate in the development of utilities and improved area access to serve the site. . That circulation for, emergency vehicles be provided through the site if feasible. 6. That groupings of major trees, drainage swales and other natural features be inventoried and incorporated in the site plans where feasible. 7. That the rezone be based on a condition that the Planning Commission review specific site, elevation, floor and landscape plans prior to site development and issuance of building permits. 8. That appropriate mitigating measures of the Final Environmental Impact Statement be accepted as conditions of zoning approval. 9. That all conditions set forth and agreements between the City of Tukwila and the applicants be attached to the fee title and be binding on all heirs, successors or assigns. APPENDIX G REFERENCES 1. City of Tukwila. Data Inventory: Tukwila Planning Area. 1975. 2. City of Tukwila. 1977. Proposed Comprehensive Land Use Policy Plan. 3. City of Tukwila. Park and Open Space Program 1976 -1981. (Ord. 964), March 1976. 4. City of Tukwila. as amended). 5. City of Tukwila. February 1977. 6. City of Tukwila Department. 7. City of Tukwila - 8. Synder, Dale. (unpublished) Tukwila Comprehensive Zoning Ordinance (Ord. 251 Final EIS Comprehensive Land Use Policy Plan. Preliminary 1978 Census Data - Planning 1978 Budget. Soil Survey of King County Area, Washington 9. USDA, Soil Survey of King County. 10. Numerous conversations with resource persons in the City, utility companies, the School District, etc. Available from field notes. DRAFT ENVIRONMENTAL'IMPACT STATEMENT FOR -: PARKCPLACE',REZONE 66/7 ivistovi 65n4444,AA)* Aws dire."(€.4__._ __ DPI S b€0 •CITY OF TUKWILA !� «. DRAFT ENVIRONMENTAL IMPACT STATEMENT FOR PARK PLACE CITY OF TUKWIIA In Compliance With: The State Environmental Policy Act of 1971 Chapter 43.21c, Revised Code of Washington SEPA Guidelines, Effective January 16, 1976 Chapter 197-10, Washington Administrative Code Date of Issue: Cost Per Copy: Responses Due: Responsible Official INTRODUCTION Project Sponsor: Dick Gilroy Northward Development Company 1115 108th Avenue N.E. Bellevue, Washington 98004 Proposed Action: The sponsor is requesting that the City of Tukwila/ approve a contract rezone and general site plans in a ; "PURD" format for a 15- acre parcel on the south face of Tukwila Hill to provide for 184 con- dominium units and 10 single - family building lots. Rezone request of the 15 -acre parcel will be broken into R -4, R -3, R -2 and R -1 9600 single - family parcels with major open space areas containing various Ye-91../A- . -b4 �tdnd -Uses: Project Location: On the south face of Tukwila Hill abo(e Southcenter Boulevard and Southcenter shopping area. The project will be north and slightly west of the new Tukwila City Hall. The site is located between the westerly extension of South 151st Street and the easterly extension.of k South -153rd Street between 59th Avenue South and �ute�th,�62nd Avenue See Figures 1 and 3. Lead Agency: The City of Tukwila Responsible Official: - Kjell Stoknes, Planning Director City of Tukwila Planning Department SEPA Reference File No.: Contact Person: Fred SatterstromTUkwila.Planning Department, 244-6290; Principle Contributors/Location of Background Material: Environmental Analysis and Document Preparation: R. W. Thorpe and Associates 815 Seattle Tower Third and University Seattle, Washington 98101 Architecture and Site Planning: Len Milbrandt Willis, McClarty, Johnson and Associates 16301 N.E. 8th Bellevue, Washington 98008 747-4050 Geology and Soils: • James Eaton, P.E. Eaton Engineers P.O. Box 126 Hobart, Washington Engineering, Utilities, Hydrology, and Surveying: Dave Halinen, P.E. Triad Associates 846 108th N.E. Bellevue, Washington 98004 ekC-' 454-0711 J, Permits and Licenses Required "—contract rezone approval, site plan approval, clearing and grad- ing permits, building permits, utility permits. 7Jr,_1 oTlf`Lv_S • • Loction...of EIS Background DatADULIUM1 / Tukwila Planning Department, Tukwila City Hall- [Vp R. W. Thorpe and Associates, Seattle Date of Issue: 14 kff4 Cost Per Copy: 4, '/ Date Comments-Due on Draft EIS: 2 TABLE OF CONTENTS Introduction 2 Summary 5 The Proposed Action 5 Potential Direct and Indirect Environmental Impacts 6 Alternatives to the Proposal 10 Measures Proposed to Mitigate or Eliminate Adverse Impacts... 10 Unavoidable Adverse Impacts 14 Description of the Proposal 17 Name of Project Sponsors 17 Location of the Project 17 Other Agencies Maintaining Files on the Project 17 Construction Phasing 18 Major Physical and Engineering Aspects of the Proposal 18 Relationship of the Proposal to Existing Comprehensive Land Use Plan and Zoning Regulations 20 Existing Conditions, Impacts and Mitigating Measures 24 Elements of the Physical Environment 24 Elements of the Social Environment 41 Alternatives to the Proposal Remaining Adverse Impacts that Cannot be Mitigated 58 The Relationship Between Local Short -Term Uses of Man's Environment and Maintenance and Enhancement of Long -Term Productivity 59 Irreversible or Irretrievable Commitments of Resources .59 Appendices 60 Rx,e, RzseeZ.Ve0 PoR. LAT. OF• RaCelPii:A/ rs SUMMARY A. The Proposed Action Project sponsors propose a contract rezone of the 14.7 -acre parcel which consists of lots 8, 9 and 10, Interurban Addition to Seattle and site plan approval to allow for rezoning of%R -1 and R -3 desig- nated properties (see Figure 3) to R -4 (Low density multi- family), R -3 (3 &4 family units), R -2 (2 family) and R -1 9600 (single - family), as shown in Figure 2, subject to conditions and site plan approval as described below. The northeasterly 3.19 acres of the property is proposed for R -1 9600 zoning to be developed with 10 single - family detached sites, averaging 10,000+ square feet per lot. The northwesterly corner, containing 2.23 acres is. proposed to be R -2 for two -unit townhouse structures and would contain 18 units. An open -space area con- taining 2.56 acres will be provided between the R-1, R -2, R -3 and R -:4 areas.: The R -3 property contains 3.15 acres of property and follows the general ridge line, as shown in Figure 6, 'Ibpography Map. This property is proposed for 32 units, in 8 buildings con- taining four units each. The balance of the property on the south and southwest, abutting ^'existing -R-4 oned property, would be developed under R -4 zoning to contain 139 units on 6.16 acres of- ground. This area would contain a minimum of 209 parking stalls in order to - accomate- the -- r-equi -r-ed- 1.5 parking spaces per dwelling unit. y l IA,^ ^r .J C--. The total proposal, then, would have 189 common-wall units and 10 detached single- family homes. All units are planned to be condo- minium, owner occupied units. The open -space areas that are in large tracts would be protected with restrictive covenants and a no-build zone imposed on the site plan approval. Access to the project would be primarily from the southeast corner via 62nd Avenue South (north of the access point to the new Tukwila City Hall), where 62nd joinsp,153rd. Street South Access for the 6 -7 tfte4/ '. 8000. II .�� I `1!+i :1 • 1.1I i:/47 ‘1,:, J.1 N1 , 1` • 1 I L. c^ ...r -M 11.1 KENNYDALE ' • `1 COLEMAN PUIN1 11.1 "t ;1 hi. • t 'L ts1 a S112ST Slot st j.C1ESS R0�(� DUYJAMZSH, •O BRYN MAWR S116 ST \`JJtsa ✓vrr ALLENTOY�N 5 124 .r Pork rt y.ICc..nti,t c� '1 •ir • ,i sr CHELSEA PARK r00 'r•'- '1,, 1 J00� • J. I j, L ... _16 ST ,9strB_j \R 1 E N ;w 152 ST s 1s2 at• r �• L L L 1 :,7I E �� ►�t `^ Illlll..___....../// v, f+ J'r f•i1:i .��� �y i Buren c..,t,� .„ , r* 160 ° ST FIVE , SUNNYDALE':.: _ CORNERS.. s " srr. r 400c RENT\Q Y HTS tJW li_�w• 1rcrrS.. • •►ewfr. n R.••••• Stv 1!I SI Tq 1 cM� 3 _ r�6 1 M s SITE u. SE 164 (T ..; J \ SE. 160 �T 1' NORTH I•,.•• I1 Bow )Labe 1•11'fr'r•Oyr 011 II uu••11 v' c.•• ,1. teg AnglenLoke • C N VI (.3 '1 • 0••w r' a) 1 COMO APt 000.Th nvom " f9 0000 •4100 • I 6" 14 024 I I I Li 1 gc411AtAttO 10011T-OP•OlAY I NORTH 0 Ala/ T •C. NAL, ITORIt P1111111111man. PARRIHO WAD OLOO. z IDOL OP PLATISLO 4-.O•APOO /7. r--. -T 69265. 00 2NQ AVE. /PUN 041 4 • • • N Or2t4EK00' 8 A 0 S J.411111110 00005 .e.o. 1....C.14411.■• GUY 137 77. .....aR4.....'t .1...nr?-.....-/..4 • /-1,41.• Bl..11r1-1. '. .',.?:-4.....,.' . G...0.4 0...4 4,..4 sit 47 1,44 I. 0145' . err PLAN t71 .•,.. 000. 44'0. 0.41.1 `7G117.7-ririt, 144 AO SO, single - family units would be east via South 151st or;north via Pik 0( 1200 7 1 62nd) and459th Avenues. The entire development would be phased over a two or three year period, building 50 to 75 units per year as the market dictates. Phasing would proceed from the south to the north under present plans. B. Potential Direct and Indirect Environmental Impacts 1. Elements of the Physical Environment Soils, Geology and Topography a. Localized erosion as areas are subjected to clearing and grading. b. Some cut and fill areas as portrayed in Figure 7, required for construction of proposed structures, roads and access points, with a net surplus of,4,000.. ,cubic_ yards to be removed from the site.-,_ c. Compaction, alteration and over- covering of soils for construction facilities. d. Alteration of topography'due to the required cut and fill. e. Removal of about 6,000 cubic yards of bedrock from the southeast corner of the site, to be used elsewhere on the site. Air Quality a. Long -term increased emissions from site - generated vehicu- lar traffic, fireplace use and heating. b. Short -term construction- related increase in dust emissions from construction equipment, open burning and blasting. Water Resources a. Some alteration of runoff quantity due to increased area of impervious surfaces, altering the flow characteristics in a year -round stream. b. Increased turbidity, petroleum product residues, nutrients and slightly elevated temperature in runoff. c. Potential diversionof groundwater movement. 9 Flora/Fauna a. Elimination of some trees and understory vegetation, par- ticularly fran the south and westerly portions of the site. b. Removal of vegetation will result in reduction of wildlife habitat. c. Adverse impacts on downstream fisheries may result from an increase in pollutants in the drainage basin. Noise a. Increase in on -site noise levels during construction, drawn out by proposed construction. phasing. Some blasting will occur. b. Some increased traffic noise from site - generated volumes. c. Exposure of new residents of the site to highway noise currently in excess of recommended levels. Light and Glare a. Addition of artificial light sources in the project area. b. Increased quantity of traffic movements at night. Land Use a. Commitment of the 15 -acre site to urban residential use. b. Increase in the intensity of land use by the provision of 139 units at 5 or more per building. 32 four -plex units, 18 duplex townhouse units and 10 single - family units for a total of 199 units. V/ c. Compatible with similar developments on the west and east and south of the subject property:':' d. Generally consistent with adopted comprehensive plan for the City. Natural Resources a. Removal of 50 per cent of vegetation and trees. b. Commitment of undeveloped land to urban uses. c. Consumption of energy and natural resources on site.. 10 2. Elements of the Social Environment Population Increase in the population of the area by 450 to 500 persons by 1981. Housing a. An increase in the number and variety of housing in Tukwila: 139. units in three -story condominium buildings ranging from 10 to 25 units per building, 32 units in four -plex condominium facilities, 18 units in duplex townhouse condominium structures and 10 new single - family lots. b. The FxDtential stimulus for conversion of other units on the hillside to condominium use, if this project is successful. Transportation /Circulation a. Increase of 1,234+ vehicular trips per day to and from the �7 proposed units including 100 trips to and from the single- family property via S. 151st Street and 62nd Avenue S, and 1134 trips to the south on 62nd Avenue S/ the multifamily units. ii b. A 10 per cent " increase ''in the daily and peak hour traffic on Southcenter Boulevard which is currently 11,300, t 62nd Avenue Southeast. c. A substantial increase in traffic volume on 62nd Avenue, south of the site, from an estimated 400 to about 1,600 trips per day. d. Slightly increased ridership on Metro Transit Routes serv- ing the area. Public Services a. Estimated increase in fire, police and aid service calls. b. The residences may contain a potential of 60 to 100 school age children, about half of whom will be in the elementary grades. 11 °' c. Increased utilization /of City, County and State parks and recreational facilities .near the project area. d. Increased private and public maintenance requirements for roads and utilities. e. Increased demand on hospital services in the area. Utilities a. Increased use.of electricity, natural gas, telephone ser- vice, water, sanitary sewers, solid waste facilities. b. Storm water discharge will include provision for retention . and pollution separation to minimize potential hazards. See Appendix A for detailed utility consumption figures. Energy Small, but incremental, increases in long -term use of energy resources at this site, including estimated consumption of about 400,000 kwh per month for electricity and an unknown amount of natural gas. �- c Human Health �� it eivb �y;;t A.o� Increased potential for conflicts and accidents from human and vehicular uses of area roads. T MBA aVt. Aesthetics a. toss of natural features and replacement by human settle- ment and activities. b. Potential seeondarydevelopment of similar character in the area. c. A change in the visual character of the area as seen from. I -405 and Southcenter,' significantly different from exist- ing development on the hillside. d. Creation of views for a majority of the units to the Green River Valley, Mt. Rainier and areas ? in South King County: kW 'U"--1 Risk of Explosion, Upset or Hazardous Emission Blasting will take place on- southeast corner of site to remove part of an exposed bedrock formation. C. Alternatives to the Proposal 1. Use of site for single family (R -1) and fourplex (R -3) under existing zoning. 2. Maximum utilization of the property south and west of the ridge line for R -4 zoning, R -3 along the ridge line, the balance of the site in R -2 and open space. 61L- cvr'�'.t- --*"`t 1 3. R - -2 on Lot 8, R -3 on Lot 9, R- on Lot 10.— t�,��'(j :L� rIcs � 4. All uses as proposed except the single - family area retaining as open space and either a covenant to keep as a natural area or deeded in fee to the City as passive open space area with a site a water reservoir acili No ac n D. Measures Proposed to Mitigate or Eliminate Adverse Impacts The following mitigating measures that are feasible and economi- cally practical with available technology have been suggested for mitigation or elimination of adverse impacts, including: Soils, Geolocy and Topography 1. Requirement for additional soil tests on building sites, and certification by qualified specialists of adequate foundation design for each dwelling - unit: it 2. Retention of storm runoff waters during and after construction to reduce water contamination by suspended silts and to reduce peak flow volumes. 3. Inclusion of no -build areas on steep slopes, storm -waer pond- ing areas and areas containing major groupings of vegetation. 4. Control of grading operations to avoid peak rainfall periods. 5. Replanting of exposed slopes. 6. Use of decks, cantilevering to minimum disturbance of steep slope areas. Traffic and Transportation 1. Control of traffic flow through site design to provide major access to Southcenter Boulevard, an arterial, via South 62nd Street. 13 Sirfi 2. =Allow' access.:to ■ortheast,.: through single- family areas, only to'proposed single - family lots. 3. Cooperation with adjacent property owners to the south and east to improve 62nd Avenue for r visibility, width and general circulation. J / Air Quality 1. Specification of construction practices to minimize air pollution. 2. Implementation of sprinkling during construction to control dust. Water Resources 1. Use of landscaping to contain runoff and decrease velocity of overland flow. 2. Use of energy dissipating devices on drainage lines descending - steep slopes. , 3. Consideration of reduction of extent of impervious surfacing. - ti ;A 4. Use of siltation devices in the interim drainage system. 5. Proper use and maintenance of oil- separating devices in the storm drainage system. Flora 1. Minimal and selective vegetation removal, particularly in the northeast and easterly portions of the site. 2. Predominant use of native species or compatible ornamental varieties in landscaping. 100�r 3. Hydroseeding of cut and fill areas att grading. 4. Native growth protection easements and no -build zones placed on areas with slopes 25 per cent or greater and around exist- ing surface water holding ponds. Fauna 1. Maintain water habitat by proper use and maintenance of silta- tion and oil separation devices in the interim and permanent storm drainage system. 14 2. Phased development to allow existing wildlife to adjust and migrate. Noise 1. Incremental traffic noise impacts can be reduced by phasing project over a two- to three -year period. 2. Limitation of construction activities to normal working hours.- 3. Use of heavily insulated buildings, double -pane windows, land- scaping, fences and earth berms as noise attenuating measures. Larger structures on south face of site will baffle some noise from 1-405 and I -5.. Light and Glare 1. Use of landscaping, fencing and building orientation to block headlight glare into dwelling units. 2. Site plan review of :orientation of parking areas, with respect to dwelling units. 110v1JY0A, Public Services 1. Provision of through- circulation corridors for emergency vehicles and police through the entire site; direct access to all buildings for fire - fighting equipment. 2. Development of recreational facilities and preservation of open space within the proposed development. (IGG - :�' .fir j f�''�b` "f ?�" Y J 3:.. Stringent',design.requirements and equipment specifications for storm drainage control. 4. Requirement of regular maintenance program for privately owned roads and utilities. 5. Phasing of the project will delay impacts on the school district. 6. Cooperate with adjacent property owners and City for develop- ment of roads and public services in the area to serve the site. 15 odloqz) Utilities 1. Provision of hookups to existing dead -end water services to provide better fire flows and water service. 2. Linkage of other utilities to provide better service for the south face of Tukwila Hill. 3. Use of weather stripping; wall, floor and ceiling insulation and insulated glass in the dwelling units. 4. Use of common -wall construction as materials - and energy- saving devices. 5. Installation of water - saving devices in the dwelling units. Risk of Explosion, Upset or Hazardous Emission Required procedures and safety'standards will be followed during blasting operations. �i1tj /t,t�iL.. Aesthetics 1. Retention of natural vegetation to the maximum extent possible. 2. Alteration of building designs to minimize occurrence of typical rectangular structures. 3. Retention of natural areas and additional landscaping and screening between different use areas. 4. Preservation of trees along ridge line will screen project from single- family homes to the north. 5. Add an additional 30 to 40 foot buffer zone along the north property . line to the existing wooded area on the southerly perimeter of the school playfields. �� it i� `J` • c 2 �. E. Unavoidable Adverse Impacts 1. Elements of the Physical Environment Soils, Geology, Topography 1. Potential erosion of soils during clearing and grading. 2. Extensive excavation of rock for roadway access at 62nd. Avenue S./. 3: SOME alteration of topography by cuts and fills. 16 Air Quality 1. Some degradation of air quality in the project vicinity. 2. Increase in suspended particulates ftcm fireplaces, resi- dential heating and construction activities. Water Resources 1. Increased runoff and decrease in water quality. 2. Slight alteration of stream flow characteristics in a year -round stream. Flora Removal of 50 percent of natural vegetation on the site. Fauna 1. Reduction of quality and quantity of wildlife habitat ir-r the project area. 2. Reduced number and diversity of species on the site. 3. Potential impacts on water quality and downstream fish habitat. Noise Increases in short -term noise levels during construction and minor increases in noise levels from traffic after construc- tion greatest along 62nd Avenue, south of the site. Land Use Commitment of 15 Acres to Urban Residential Use 2. Elements of the Social Environment Population 1. Population increase of approximately 450 to 500 residents on the site. 2. Addition of 60 to 100 pupils-children to school district. 17 '; 2 Transportation /Circulat'ion.r 1. Increase of 1,246 trips per day to and from the project, primarily at the southeast corner of the site. 2. Short term construction - related increase in local traffic volumes. 3. Traffic volumes on area streets after completion of pro- ject will increase substantially on 62nd Avenue south of the project and by minor amounts on other roads. / Utilities Increased use of electricity, natural gas, telephone service, j water, sanitary sewers, solid waste facilities. (See Appendix A for detailed utility consumption. figures.) Energy Small, but incremental, increase in long -term use of energy - resources. ,--Human - Health I-Increased potential for conflicts and accidents from human and vehicular uses of area roads. Aesthetics 1. Loss of natural features and replacement by human settle- ment and activities. 2. Potential secondary development of similar character. 3. Visual character of area, as seen from I -405 and South - center will be significantly different from existing development on the hillside. 4. Creation of views for a majority of the units to the Green River Valley, Mt. Rainier and areas in South King County.. 18 II. DESCRIPTION OF THE PROPOSAL A. Proposal; Name of Project . ..Sponsors '? r:- The Northward Development Company of Bellevue, Washington, re- quests approval_of_..a'Jcontract "rezone with certain conditions as set forth iri Appendix) _F, to allow for four new zoning areas: R -4, R -3, R -2, R -1-9600 respectively. The areas, as shown in Figure 2 would provide for 134 condominium units in the R -4 area and build- ings ranging from 10 to 25. units per building with an accompanying 201 parking places. The R -4 would cover 6.16 acres. The R -3 zoning in the center portion of the site (3.15 acres) near the existing ridge line would accommodate 32 units in eight 4 -plex buildings, two stories in height with parking for 64 cars. The northwest corner of the property, 2.23 acres near the existing R-4 zoning on the Graden Smith property, would be developed with 9 duplex townhouses totaling 18 units, with attached covered parking places for each unit. The northeast corner of the property, 3.19 acres, would provide for 10 single - family detached dwelling units, open space and a major retention pond for surface runoff. Sepa- rating the four areas would be 2.56 acres of open space areas pro- tected by covenants from building or clearing. B. Location of the Project (See also Figure 1) The project is located on a 15 -acre site on the south face of Tukwila Hill in the City of Tukwila, northeast of the interchange of 1 -5 and I -405 south of Seattle. Legal description of the property is lots 8, 9 and 10 of Interurban Addition to Seattle. C. Other Agencies Maintaining Files on the Project There are no other agencies known to maintain a numbered file on the project. D. Construction Phasing The project is proposed to be phased for construction beginning with the R -4 portion of the property on the southwest, then moving 19 ,t ,. 4.0 to the lower density zones. The single- family lots may be devel- oped earlier if the market is favorable. The entire project is proposed to be phased over a two to three year building period, with major construction occurring in the dry seasons of 1979 to 1981. -,',,Recreational .facilities (tennis courts, swimming pool and recrea- ' v; jr ,\'' -utilities- for most of tice site, all, roadways and other common ', tional building) will be developed as part of phase one as well as 1-1 __ .., .,.. . . ._ :...._. facilities. < Construction of various ti:additional elemments on the site will be in response to detailed market studies and demand . during the next two to three years. E. Major Physical and Engineering Aspects of the Proposal The streets, lots, building configurations, parking arrangements, open space areas, access points, drainage channels, trails, recre- ational facilities and other elements are shown in Figure 2. These are also supplemented by other drawings submitted as a part of the zoning application, including but not limited to: 1. Site analysis, topography, tree and major vegetation group ings, drainage patterns, view analysis. 2. Development concepts including access and circulation patterns. 3. A grading Plan including cut and fill areas. 4. Utilities plan. 5. Site sections. 6. Landscape Plan. 7. Architectural details including elevations. 8. Typical development, unit types. 9. Phasing of construction. The application for rezone will designate various areas of the site for specific zoning uses with the understanding that a Planned Unit Development approach is being applied, to guarantee . that the site design is consistent with the goals and policies and the map portion of the recently adopted Tukwila Comprehensive 20 ' (Dc ei LA.) > C fl. r r) aw r rP r • I ob. : Y! • 1�0 Nn _-- I S]!5 1. 6 .vo 1 • 1 4. - e.• r^ CO L414IJ1 X40--.--- - '6471 • t • 4 -- - N - r‘..)+ -i- • • • •. • ., t4 cs 11 •ru rieg. xi 44 [.TAT 104 c91/43 D4 iZ) 40J-14:1251.4 f% r.+ 1N t•4 : i?-1 •t I. • 1.5 aa(1 IN r•3 111 %1• 64 is i1 IGk 7.4 �1 . NT. 1. —'?4 • 116 iv. R•4 C , R-2. o.. n., k>rc L Cnf Cer,: n. • r Yr IOCtr•001 L•wALS F•MiW R•I•oo ors Sothenebizy !.U3 tea p•0 - ro+�ts W 71 Mb M, cda rtli t 33613A PS. In 747 -4oGO !)V 7Plan. The proposal would gradually reduce the density of dwelling units as one moves from the south portion of the property north- ward and east. Steep slope areas are preserved in an open space system. Existing trails in the area are linked through the site. Major tree groupings have been identified as reserved for preser- vation in the conceptual site plan. Two small pond areas would be enlarged and utilized as a part of the open -space system for the collection and detention of peak storm runoffs. The more dense development is proposed to be restricted to the more level areas of the southerly portion with less existing vegetation. Most of the desirable types of trees such as the conifers, large maples and associated understory will be left in natural areas. Access is proposed for most units over South 62nd at the southeast corner of the site, with only the 10 single - family /ots gaining access to the northeast. However, major cuts and fills with accompanying retaining walls will be required at the southeast corner of the site to provide access to that intersection. The site plan pro - vides for through circulation for emergency vehicles only, through push -down barricades. The entire project will be units for sale. No rental units are . proposed as a part of the project. Community facilities will be provided for the entire project, a homeowners' association de- veloped and protective covenants, restrictive. and conditions filed as a part of the overall condominium subdivision approval. Price range of the units will be determined by market forces, but gen- erally range from $42,000 to $65,000. At present the site is totally undeveloped. Other than logging, past activities on the site were limited to provision of fill in the 62nd Street right -of -way at the northeast corner of the site for a distance of some 200 to 300 feet. This partially impounds water flowing off of the elementary school site in a small pond. Clearing and grading of approximately 50 percent of the site would be required to implement the proposal; leaving major buffer zones. 23 along all four sides, particularly the north, east and west to screen the project from along the easterly ridge existing wooded and open of- the property 4, E. Relationship of the Proposal to Existing Comprehensive Land Use Plan and Zoning Regulations 4 1. Tukwila Comprehensived/41' 6' 'PH The recently adopted Comprehensive Plan contains several ele- ments, including a Goals and Policies section and a map that serve as a land use guideline to assist the City's review bodies and staff in evaluating zoning applications and land use matters. As depicted in Figure 5 the site is divided into adjacent .uses. The open space system line . would-beET provide a linkage to the space areas onAthe school yard and -east-- • • VI" 1,(!' three (as follows: The southwest corner is high density residential (over 16 units per acre) the central portion and majority of the site medium density residential (7 to 16 units/acre) and the northeast corner low density (0 to 6 units/acre). The ridge line is used as a natural demarcation between medium and low density. The proposed site plan and proposed development have been designed to be as consistent as possible with the map, and the directions given to the previous property owners by the City Council, Planning Commission and City staff during the corn- prehensive planning process. • The plans also reflect the Goals and Policies section pf.:•,the.... 0.1W6k.FT Section 1: Neighborhood Objectives and Policies Objective 1, Policy 1: 9, 'Euffer zonse\boundaries are based on topographic features. Plan as summarized below. 24 El LOW DENSITY RESIDENTIAL (1-6 DU/AC) El MEDIUM DENSITY RESIDENTIAL (7-16 DU/AC) Fa HIGH DENSITY RESIDENTIAL (17+ DU/AC) CI OFFICE J COMMERCIAL O LIGHT INDUSTRIAL El HEAVY INDUSTRIAL LI PUBLIC FACILITIES • PARKS AND OPEN SPACE —n LOX SPECIAL DEVELOPMENT CONSIDERATI / b,Ayy ranas To AREAS CS. STEEP SLOPES, WATER WWII:E. *AO ACIIECLLTISW. LANDS. TWS DESIOYOOPI DOB sCT IIIL•••CLUDI DE YEIDRAEPIT: RATHER, IT DEPICTS /EELS *MERE DRDAA CEVELOPsIOR PAST RESPOPO .5iDts•MYEUTOCEATAN ENVIRONMENTAL MEMEL PLANNING AREA BOUNDARY Damao CITY BOUNDARY - • ' - : - - - -a.W. 1 IIIIflIflJJIIIIIIIII • I I 1111111111111 , uIIIfl DIE •14 FIGURE 5 PRELIMINARY EHENS1 q111-,t ), E E PLAN ifiq ARM &E-A1Pn • RESIDENTIAL COMPREHENSIVE LAND USE MAP LEGEND: d , • P: � .; r. Low - density residential: These areas are characterized by single - family residential uses; 0 - 5 units per gross acre. Medium- density residential: These areas are multiple - family in nature and are characterized by duplexes, triplexes, and fourplexes; 6-16 units per gross acre. High- density residential: These areas are multiple- family in nature and are characterized by apartment buildings; 17+ units per gross acre. COMMERCIAL Commercial areas include commercial services, retail commercial activities with associated warehousing, and compatible and complementary uses including offices. INDUSTRIAL Light industrial: Industrial areas characterized manufacturing uses, commercial and offices. Heavy industrial: Industrial areas characterized turfing uses, distributive and light manufacturing. uses. by distributive and light by heavy or bulk manufac uses, commercial and office PARKS AND OPEN SPACE These areas represent.public parks, recreation facilities, school playgrounds, and other public open spaces. COMMUNITY FACILITIES Community facilities include school buildings, churches, government offices, police and fire stations, and utility facilities. SPECIAL DEVELOPMENT CONSIDERATIONS Refers to areas of steep slopes, water surface, and agricultural lands. This designation does not preclude development; rather, it depicts areas where urban development must respond sensitively to certain environmental factors. P\ Policy 2: Subject property'has a "park. and- `playfield on. the north and the • applicant proposes buffer zones on the north and east to sep- arate it from undeveloped and potentially different land uses. 4,a a i3 olicy 4: /..1) Vehicular traffic can be primarily channeled to the south to-1140Q4- :apartment and commercial zones. Access to arterials is direct. via 62nd Ave. So. + ha- ,�,f C: fif Objective 2, Policy 1 :, .:I---`- The proposed contract.rezone and site plan approval, utilizing a varying density of development would provide for a medium density transition area between high and low density residen- tial areas. MPolicy 2: This development would be located functionally convenient to primary arterial street, shopping, employment and other facilities within. the Tukwila planning area. Objective 3: Maintenance of buffer 20riea on the north and east, particu -. larly the steep slope area, will provide compatibility with this objective. In addition, the following items are respon- sive to policies in this section. ,r. (i , �')(\r(i r �- � T; t . Grp Lev 1. Screening of adjacent uses. nl'e) V 'tit 2. Undergrounding of all utilities. i. i. 3. Maintenance of natural open soace areas. 4. Provision of guest and recreational vehicle parking. 5. Provision of trails to link activity nodes in the area.. 6. .Encouragement of recreational open space within multi- family development. 27 Section 2: Housing Objectives and Policies Objective 1, Policy 1: With the proposed development, because of its size (i.e.: 15 acres), it is possible to encourage housing development with a diversity of housing types. Duplexes, townhouses and four - plexes are envisioned on the less dense portions of the prop - erty, and the R -4 area provides a mix of condominium units with 2 and 3 bedrooms. Policy 2: Townhouses and condominiums are all that are proposed for the site. The following Objectives and Policies have also been consider- ed in the proposal. Element Goals General Goals 2, 5, Natural Elements 1, 2, 3 Open Space 1, 2 Residence 1, 2, 3 Transportation/Utilities 3, 4 Element Natural Environment Open Space Residence Transportation/Utilities Storm Water Systems Underground Utilities 28 Objective Goals 1 . 2, 3 .3 1, 2, 3, '4 4 3, 4 5 1 6 1, 2 8 1 1 2 1, 3 , 6 3 2 (See Previous Text) 1 4, 5, 6, 7, 9, 11, 12 6 3, 7 6 1, 2, ;1ri,.c1 2. Zoning Code The proposed uses jwill comply with the appropriate sections of // the oning ode(for R -4, R -3, R -2, and R -1 9600 classifica- tions. All density, bulk requirements, site coverage, parking and other requirements have been reviewed and incorporated in the plans. 3. Building /Fire Code Provisions of the UBC and Fire Codes will be observed and .changes made if necessary to comply. 29 :;�?.?�{ ,- _� }� °• INDEX OF ELEMENTS OF THE ENVIRONMENT A-ELEMENTS OF THE PHYSICAL ENVIRONMENT • Earth Geology ;. •_ • • . • • -. . • / Soils ■•■;,/ • .1. • 1. • / • 1, • Topography . • . • Unique physical features . . . . Erosion _; . Accretion/avulsion • . • 1)/i. Air Air Quality Odor Microclimate Water Surface water movement Runoff/absorption Floods Surface water quantity Surface water quality Groundwater quantity Groundwater quality Public water supplies Flora Numbers or diversity of species Unique species Agricultural crops Fauna Numbers or diversity of species Unique species Barriers and/or corridors Fish or wildlife habitat Noise Light and Glare Land Use Natural Resources Rate of use Nonrenewable resources Risk of Explosion or Hazardous Emissions . . . /10 - 6 ELEMENTS TO THE HUMAN ENVIRONMENT Population Housing Transportation/circulation Vehicular transportation generated . . Parking facilities Transportation systems Movebent/circulation of people or goods Waterborne, rail and air traffic . . . Traffic hazards Public Services Fire Police Schools Parks or other recreational facilities Maintenance Other governmental services Energy Amount required Source/availability • • • . • • • • . Utilities Energy Communications . . . . . . . . . Water Sewer Storm water Solid waste Human Health (including mental health) Aesthetics Recreation . . Archeological/historical Additional Population Characteristics • • Economic Factors • * III. EXISTING CONDLTIONS, IMPACTS AND MITIGATING MEASURES A. Elements of the Physical Environment 1. Earth a. Existing Conditions Geology and Soils A ground reconnaisance of the site was conducted by a soils engineer (see Appendix A for report). Shallow glacial till, weathered on the upper two or three feet, grades downward into a glacial sand and gravel formation. A bedrock formation crops out on the southeast property corner. Both bedrock and till provide excellent founda- tion strength. The till appears to be stable, with no evidence of sliding. Soils OH the site are not analyzed in the Soils Conserva- tion Service's survey of King County, other than as gen- eralized "Urban Soils." Productivity potential of the site can be assumed from the apparently thin till soils to be low, other than its for an average potential for forest.No unusual soils conditions were observed, except for the exposed bedrock, which poses no problem to devel- , t� lc opnent except difficulty of excavation..,:, .�. �' 1' AA r , Topography �— } Y; ` The site has wide ranges of topography and slope with a ridge line as depicted in Figure 6, running from the northwest corner of the site southeasterly to the east property line. Elevation of this ridge line varies from 230' to 255.6', but generally averages 240' in height. From this ridge line, the property falls off to a low point near elevation 140' in the northeast corner and along the existing drainage channel. The property also falls off to the southerly property line, at roughly 180'. 32 .... 7 • n. \ • ,4•1 A CI 44 ,ies \ks , • • 10 , 1 . le . 1 0: . # • • 4*/ ,,,,, lq, [I -,, , . te , .... I ., 1..1-- , ..• s'. _0' .., ,. '?1 er 1.:., . ,Z. 7 0 (:11,-4 "L<•./.7.". ....:.' ' ("4.....411 i,),‘,.;‘ .1.•;47,0*,1"..i.-2.....;_;.:.1.1/ ".' r r_. tos • #4/ , • • , 004. I .1 / e; . • . „.. / I I 0* • • e ' ' -4. • -- tr' 1 I I I )1#\ • ; e.# I. iv ti• , , .4. 9• .1 4 I / e•! I - ' ° : • , --,---/, ,.. ///: #. A: \ ,...1. ,i1,----,:L...-` - "! ...' . ,.... 0,- c , • 12 ' 0 . 0. . .•i. ., ,,..--17,-. . ' 1 ......,,,,,. --.., , , , „,,,___. , 7 ., I . ,.- .' . .•,..'o,, I I ' / -110 I 7 . ,t• , .. ........0, i: -0.--fr '`:,:id . •- . ' 0,' ' s. ,, . ' . 7....-.-- ,■ ... = ••••• .• r, `?.. ,,'• .; / , , • P ! . • .. ii ‘ ... . • . ■ -- "-. ; i',..7'j A . . . / . 'A'l 4, f. / i %VI /0' / 1 . 0. .; I I • 1 / I, cot.: ' ji..'..• 1:40' ).' •.11......___H--1 7.1-....';'':' • ..'; .4,r.'''' . :II. 4 .:...''. 0. , .A. ' ,... /#' I i / e • .1' 0 I . :i 0 e0 1.11. I 0 ..1;,$.d ..."-- ' et- -' /" "" t•• '',...., •■• ••-.1.1"d7. I . .1 ; . /1 / j / k,4,1'„6-•• ,„„. /• ,,1-0.-,// I // . 1 1 II. IN, 7 , ... / , i,f : / / ,,, ... • ( 1,, .1 1 / i: i I I I I •• i' °; s ' ' : e 1, ( : I I ,l i '4;0/ .4 0' "31,:i•-■ I i 1 ‘ es .. / . : ‘ : //r/I . . , 7, .el' ,4>,. 7, : >, /. ' PL, 71: :I :. : , - . . . -0 : : 7 -.-7S-'7'. / Jo.. .... ./,,,, • ,„ . , ... ..,...... .. T. . ,..,,, ,_. N..... ...,...ii , • „...... ..._, —,-,- . N..: - .....-- . . , -,,i."- -- - .-: • ; .. -., ._ - , \ ....,...., //\,, .. '`-.1 • , ) / i 1 . • 1 r 1 „, 1 \,,,., ,J..1,L,,:ou,i ,„....1,1_,,,,,&„,,i,,;,('1c-ie;,.0/ . ,/,/,... ____0;,..,: • - .• - • , , . • . \ 11 -- " • ,,, , , ti A 41. t • • II ■.• E,•••• C•E r • ft, • •• • - ;;;- • * • I, 0 • • - .41 IA. ••••••"11.- ' 4, • 4:4'1 •40 • " ji IN Or • , .0* r I , 0 it A A AN./ /11••••••• NW, .6; . 2 4.1e-e r••■••• L4L DE5CP/P7/ON telen 0.9 I., 0.100•••eubv Arkwarsv fkft•gelI rars,ZW”sfegv.gyr.:•-''AV r1:7117;t:;k•r=";=Tela ISPI• !Tee,. der...VW TWACIO • • • fag.71 .1.1;r17,!•11."V.47." `"' ••••;::• • i •, . .1" • !;•••,,..: 2 4 1 •CP.)411 The westerly property line drops from 230' on the north- west to 165' on the southwest. The average slope from the ridge line to the northeast corner is 21 per cent and the average slope from the ridge line to the southwest corner is 12 per cent. The slope, ridge line and two low points where some ponding occurs are depicted in Figure 6 - topography and 10 - drainage basins. b. Impacts Geology and Soils As noted below, a considerable amount of soils relocation will take place on the site, with cuts of 20,000 cubic �. yards, balanced by 16,000 cubic yards of fill. Approxi- mately4,000 cubic yard(txces-S material will be used in earth berms9lex portedefrom the site. The bedrock outcrop- ping will also be reduced for the southeasterly roadway entrance. Most of the rock is expected to be used on the site. 1(6:;0 The impact of the soils relocation on site will be related to the topography. Till soils are highly erodable if exposed on steep slopes. Selection of slopes, and place -. ment of unconsolidated till soil, hardpan or bedrock exca- vation materials in fills will need to follow 'the known limitations of these soils. Erodability of exposed sur- faces, stability of compacted materials and critical mois- ture content during placement and compaction of fills will 1 V ` r��,t,.+ s t be taken into account in site design. The stability of cuts and fills, as well as groundwater, will be. critical at the foundation locations. Mitigative measures should be specified after the buildings are ten- investigation tatively located, and after detailed soils at these locations. 4 \. 34 Topography Grading operations should have a range of effects on the topography. Significant excavation will occur at the southeast corner of the site to accommodate the access point. Total excavation of this area will be approxi- mately 6,000 cubic yards, largely bedrock.. In certain areas, as depicted in Figure 7, cuts and /or fills will occur in order to provide for building pads, parking areas and roadways as a part of the overall site development.. The proposed buildings would utilize existing contours such that foundation excavation would be minimal. The general estimates of cut and fill shown in Appendix C indicate that approximately 20,000 cubic yards of material will be excavated and approximately 16,000 cubic yards of that material used for fill. The bedrock cuts can be utilized for roadway subsurfaces. Wherever possible, topsoils can be stockpiled for use in landscaping, berms and other surface treatment following construction. In some instances excavation for foundation and parking areas will be fairly extensive to accommodate conventional foun- dations. Significant grading and cuts and fills will be required to provide a roadway linkage for emergency .ve- hicles from the northeast corner to the central portion of the site. Road grades will range from 2 per cent to 14 per cent except the fire lane linkage which will be 16 %. The entrance grade is planned to not exceed 12 per cent. Existing land contours will be,sligaltered by excava- tion, and relocation of fill material on the project site. No materials are to be imported and only excess fill ma- terials exported. Excavated materials will be balanced on the site during preparation for construction On grades which exceed 8 per cent through the site for long distances increased runoff could create soils slip- page potentials. Eroded sentiments carried by runoff 35 co t♦ •! • • t^ ' • :. ...f . 0B •3AV aN 019 4ift ••f nM ' +T7 z z .09 ..1 •! NV7d ON! V�lO ---.O T.V. ti1 Tr It If • .ry f: if ni:i•avM ••ry.f,..•� 9. 0•■••••••• ••.c•1•+1 ef•cj....1n•.'•pB •3AV ON L9 n�+•`��•.� • 00•SZ6 r3• .b It- 10 N • " .�.. _. • • •m.. a. Ve■ MO,. '1W L. 011 Ai.IC 01 • A c.1 . v11 • W C=4 H i••• ,10 101 3 .Ia 60 Z0 N d' � !^ N1tlMN ea 8avaleNl NYtal no v--a: re r�ivn stair. i 210 Ttd ln7 '9a'a 4.•V . C ri • • A.t A•1l �.. NORTH v.4. • .., ti �ry It . yN .02•x. 2• • .2 f { 01 140'E 925.00' • -.. �i /;44fr;, • 62■0 AVE. GO... • ,.■'• • 0 C AA :% AREA OIT TOTAL VEGETATION RETENTION SITE PLAN OF • EXISTING CONDITION$ AMAI Aft tOVI.N N NIIO,.I'. AO *AVM. WIY CAAOOG 1.04 ATQYtN0 OM MOM. N NCtk.tIAO. GILL Al *A.l{•AtlO NtN Y TI AMA). AN A Ol.lr4 or Autivl nun. ON AI Ill YiAII.0 q, urge. yu.11siilllpramo, HAMM • sou. At10 {MUM v11.1. N I4CN N AMIMIN OT/utivA WAR. 2 161St 6T. • • (.ON F I 62 NO AVE. GO. FIGURE 9 -1 GEOLOGIC CHARACTERISTICS I[1 TUKWILA PLANNING AREA C7 J. ni x m • • Features Foundation Stability Seismic Stability' Slope Stability Alluvium (Qa) Laid down \by rivers after Primarily silt, clay, retreat o \glacier. with some peat. ,;w - ., Lacustrine deposits (Qic) - / Deposits laid down by Silts and clays. great lake ins \Duwamish Valley when gl rifer blocked drainage to the north. Outwash deposits ((Ivo) Ground moraine la4,0 down Sand and gravel. by Vashon glacier Mich has O been washed by streams and - melting ice. O Lam' Ground moraine (Qvt) Also; alled Vashon ti11L Compact mixture of This is the material which clay, sand, gravel, feT'1 out of the ice as and boulders. O Vashon glacier melted back, /into Canada. \. 0 O Glacial, non-/ glacial deposits (Qu) Glacial and nonglacial ;Undifferentiated de- „, materials laid down prior posits of sand, silt, O to Vashon glaciation. clay, gravel and till. Bedrock (TpTb) Includes sedimentary and Folded sedimentary volcanic rocks which formed rocks'of Renton Form- 00 in preglacial times. ation.`,Also includes intruded basalt. 0 GOOD C) FAIR POOR Adopted from: Preliminary Geologic Map of Seattle and Vicinity, Washington, U.S_ Geological Survey, 1962; Donal Mullineaur., Geology of the Renton, Auburn, and Black Diamond Quadrangles, King County, (Geological Survey Professional Paper) No. 672, 1970; and An Ecological Study of the Kent Lowland, Kent Planning .Department, 1971. FIG.. 9 -2 S IL GROUPS: DESCRIPTIONS AND CHARACTERISTICS TUKWILA PLANNING AREA " GENERAL SOIL TYPE MARSHY SOILS ALLUVIAL TILL SOILS OUTWASH SOILS ROUGH, BROKEN AND STONY LAND General Description 1 • Wet areas, depres- sions of peat and muck. Level, gen- erally shallow • soils. Deep sedir ntary soils of silt :, clay and some \ peat developed in valley alluvium. \� - \ Thin soil lay r developed:,over im- permeable'glacial" till or /bedrock. Relief''gently rolling or hilly. Gravelly, dry soils developed . over glacial out- wash deposits. Relief generally rolling or hilly.. Variety of soil types found on steep slopes. - • Bearing Capacity Low Low ? High High Low Erosion Hazard Slight Slight Y' \Slight Moderate Severe Internal Drainage Poor Poor Fair Good Fair - Arability Fair. .. Good i Fair e - Poor'. ' Poor - Characteristics related to urban development High water table and low bearing capacity require- filling prior to development. These areas serve to store runoff, and if drained, an increase in peak storm runoff will �% occur. High water table and low bearing capacity require much site prepar- ation prior to development. High fertility of soil wall suited Ito agriculture. Hardpan occurs only a few feet`\ from soil surface\ .and restricts ' \. downward percola- \ tion of water. Soils will support heavy structures. Slight erosion, increasing to moderate erosion in slopes exceed -• -. ing 15%. - Excessively dry soils which are subject to ero- sion if cleared. Good soils for ,,buildings with "'basements. Pro- vide good drainage for, septic tank • drain fields, but may cause possible groundwater' pollution. Steep slope pre - cludes construc- tion of roads. Intense develop - ment impractical. High erosion hazard in these soils, especial - ly if stripped of vegetative cover. Soils are Ben- erally unstable. Source:/ Soil Conservation Service, U.S. Department of Agriculture, Soil Survey of King County, Washington, 1973. rt >, could cause turbidity in the stream that runs through the I f site. c. Mitigating Measures Geology and Soils Installation of siltation basins, drainage velocity dissi- pators and foundation drainage systems could mitigate the adverse impacts of soil erosion and reduce the potential for soils slippage. Restricting grading operations to periods of dry weather and replanting exposed slopes could reduce soil erosion. Installation and maintenance of temporary and permanent drainage control structures could reduce the sediment load that might enter the natural stream system. Detailed soil borings and analysis on all building loca- tions should be undertaken by qualified soils engineers and consideration be given to rearranging proposed build- ings if soil conditions dictate. The soils and slopes to be encountered are not thought to be unusual for the area and_ are commonly built upon . safely, provided engineering recommendations are followed. A detailed engineer's report on foundations for each phase will be supplied with final building and grading plans for that phase, together with recommendations on standing cuts or slopes, filling materials, compaction and drainage systems. Topography Use of rockeries and retaining walls could reduce the extent of topographic alteration. Use of pole or pier - type foundations on steep -slope areas could decrease grad- ing requirements and;- thus mitigate adverse impacts on existing topography. I, i 1 %1 ��f',.„ ' J' ' `l�r, �;' ?l'. ir, .;�• i./!_. i .�f;�I:�. ''j •�t..' !..•E,+', ti c f �i 1 ' r r . t 40 2. Air Quality a. Existing Conditions. The most significant factor affecting ambient air quality in the vicinity of the proposed project is automobile traffic and airplane traffic from Sea-Tac Airport, Boeing Field and Renton Field. The site is located on the south face of Tukwila Hill, which is bound on the south by I -405 and on the west by I -5. Sampling of particulates and sulfur dioxide has been carried out at Southcenter since late 1976. Air pollutants contained in vehicular exhaust emissions include carbon monoxide (CO), hydrocarbons (HC), and oxides of nitrogen (NOx), of which carbon monoxide is the pollutant of most concern. Carbon monoxide levels were monitored during 6 weeks in January and February of 1977. Maximum 1 -hour concentrations did not exceed 11.5 parts per million fa any time. This is one -third of the maximum 1 -hour standard of 35 ppm. Eight hour averages were under 4 ppm. Traffic congestion, characterized by a large number of slow - roving or idling vehicles, occasionally results in. high CO levels in the area, particulary on days when the wind is light and stagnation or inversion conditions exist in the Green River Valley. Prevailing wind is from the southwest in winter and the northwest in summer. The average daily traffic volume along Southcenter Boulevard is 11,000 vehicles per day, on I -405 66,400, with vehicles concentrated periodically around Southcenter. Suspended particulates are another source for air pollu- tion, chiefly responsible for reduced visibility in the Puget Sound region.; Sampling developed by the Puget Sound Air Pollution. %'Agency (PSAPCA) indicated suspended particu- late levels ranging around 45 mg per cubic meter (ug /m3) 41 .._ .. .. in 1976. Compared to 1975 maps for the same parameter, Tukwila and King County in general appear to be experi- encing an increase in suspended particulate levels in the atmosphere; in 1975, the same area showed an annual mean of 33 ug /m3. Traffic along the above mentioned roads can affect pollut- ant level in the project area, particularly during periods of low wind velocity. Vehicular exhaust fumes tend to follow the upward slope of the site and odors from this source would be most noticeable with the onset of morning vehicular traffic. Airplane exhausts occur in the area and are a part of the general air quality. b. Impacts Unless an increase in congestion at intersections is caused, air pollutants generated as a result of this pro- ject should not have a significant effect on local air quality. • The peak hour traffic levels, in the range of 125 vehicles per hour, slightly more than two cars per minute, on 62nd Avenue South, should not cause any great increase in concentrations in the area. The rise in pol- lutants in the significant areas, along Southcenter Boule- vard and I -405, may rise in proportion to the traffic levels. This project should add less than 1% to the traf- fic through that corridor. '(Estimating 70% of the site's A.D.T. (794) -allocated to Southcenter Parkway, between 62nd Avenue and the Southcenter access overpass, -where ... total A.D.T. -=,is nearly 80,000.) No significant increase in the probability of violations of local ,'air quality standards' is therefore expected as a result of this project. c. Mitigating Measures Vehicular exhaust emissions should be reduced as federal}''' vehicle emission standards becone . effective ; and ...older 42 . '?vehicles.-arereplaced: If peak hour traffic volumes on Southcenter Boulevard result in significant congestion at the intersection of 62nd Avenue South and Southcenter Boulevard, provision of turning lanes may be considered. [1 1 0i4, [- j -f i bG , '14,1 ,_a C.,1";4:11 Sprinkling could be implemented during construction per- iods to reduce airborne dust. 3. Water a. Existing Conditions Stormwater runoff generated by the site currently drains . in three distinct directions. The northeast portion of the site drains into a well- defined drainage swale._ This . swale, which also receives drainage from the developed area to the north, broadens to form a shallow pond about one foot deep and then runs from north to south eventually emptying into the I -405 storm drainage system. As well as conveying stormwater rUnoff, a small base flow of approxi -. mately 0.1 cfs exists in this swale and acts as the source of the shallow pond. The south portion of the site drains into the currently undeveloped property to the south. There are no distant drainage swales in this area. Runoff travels essentially as sheet flow until it is intercepted by S. 154th Street and routed into the I -405 storm drainage system. A shallow depression which has a maximum depth of approxi- mately 3 feet exists adjacent to the site's west boundary. Approximately 2 1/2 acres of the site as well as 1 1/2 acres west of the site (the only offsite area draining into the site) drain into this depression. This drainage is apparently the source of standing water at the depres- sion which is probably seasonally intermittent. 43 .147,- Sr \ FIGURE 10 (1, 1 \MI • EXOSTI G RAMAGE F0/4q / ) / / (, -N ) • ) ( M c ( • X ( I \\ \37,vilyeb. • \.) Arm ‘-.. : sLsTE !Wrier/ Or: SEC fl,raP23,,f4e CRAmeta eAsar-imer I role& I ,iT n-.:tt,4 ciry iach Ca4sfax7civ) 0 co r--A3 RAI --. ASE6ATES' POI W 44-01M 1 FIGURE 11 - 1. Ai GE PLA 1 ■ - - .14 : INIERVAL COYYEMNCD, ROCIIING INRU DETLYTION • l'ACILINeS,ANO DISCHARDI • 1DRAORDSED STRIA DRAIN 6 II 'SITE • .....sibMON '&c e3. ritne3M.E.1 • • s LT/InAis DirrALC-1 77JAWV CIT1 Auct / ILACk:DCOYJnitiCirld c.15‘174'0 es ,e‘ TA 4' ASSOCIATES raps,' 444.07„ • _ a • • / r-s\ \ FIGURE 12 • • • SYSTEM 1. • trig:* ermao MEV [mire I7tt HIM:" ( Ftt ./5/- \ \ • , 1. \ Ns \ I ) - I • LiNgS • AVERAGE 11.410. fONSmP770/1. • ; 71000 GAUOMS • • 1,t- TE 1:87/NO C• mom MAIN tr • . 4**.o. ••• C.:7CD 1 / g) • t Ss- .-,16-riali Ur: . •.Stc,:...a..1.11,A•2314RJE - "MAD ASSOCOATES 1 fJ 1_, .47 ruAirt4 CITf /-LL 11 rszirsis KY) 7.30 ■70 Public Water Supplies Tukwila provides water service for the proposed develop- ment as well as the existing development in the City. Construction on the site will not interfere with an source of public water supply. Impact Surface Water Movement S_ (See Appendix B). _ Qg Runoff Absorption /kV/‘ kW/ Clearing, grading and construction of extensive areas that will be covered with impervious surface materials will significantly alter existing runoff and absorption char- acteristics. Site runoff could be expected to increase by more than five times in some small areas. Drainage deten= yo tion systems may be utilized. to control the surface run- _ off. Absorption of precipitation will also diminish signifi- cantly as a result of interception by parking areas, roads, rooftops, and other impervious surfaces. Approxi- mately 60 per cent of the R -4 dwelling areas and 40 per cent of the duplex and single - family areas would be covered by such 'surfaces. Average site coverage through- out the project would be approximately 50 per cent. Surface Water Quantity Surface water quantity would be adversely affected to the extent that runoff is increased and absorption is decreas- ed. Drainage control structures sbould prevent the in- creased rate and volume of runoff from adversely affecting peak stream. flows. However, reduced absorption could '+ ;-result-in-lower low - stream flows.` 47 tv- Surface Water Quality Clearing and grading activities will cause erosion of site soils during construction periods. Eroded sediments could enter the stream as runoff and result in turbidity. Runoff from parking areas and roads could contain petrol - eum product residues. In addition, runoff from impervious surfaces would have slightly increased temperatures and nutrient levels. The adverse impacts on the water quality would be most significant from runoff during seasonal low flow periods. Groundwater Movement Deep excavations required for placement of large buildings on the hillsides in the project area Could intercept groundwater movement. PVA= w- 511114 c. Mitigating Measures Runoff/Absorption Landscaping features, such as berms, gardens, and porous walkways, as well as grassy areas and natural areas that. would induce vegetation, could detain runoff and decrease the velocity of overland flow, substantially reducing peak runoff volumes. Use of the two existing ponding areas to . detain runoff and detention facilities in the more dense :. parts of the proposal could decrease runoff and increase absorption. In some areas where feasible, the combination of splash blocks and bored recharge shafts. might be utili- zed to increase absorption. Perforated steel piping for underground portions of roof drains could permit greater absorption and reduce surface runoff. Reduction of the extent of impervious surfacing could be encouraged to decrease the quantity and rate of runoff. Surface Water Quantity Mitigating Measures suggested by Triad Associates in Appendix B for increasing absorption and detention could 48 ... �, ',., mitigate the potential impact of peak and reduced low flows. Surface Water Quality Use of siltation devices as a part of interim drainage . system during construction could reduce the potential for turbidity and sedimentation in the stream. The storm drainage system could be equipped with oil- separating devices which, if properly maintained, would reduce the potential for petroleum product residues to enter surface water. Wu-S(11NA. 4. Flora a. Existing Conditions Like many of the areas surrounding the Green River Valley on the plateaus, the site of the proposed development was densely forested in its native state prior to intensive logging that occurred in the early 1900s. However, sig- nificant groupings of vegetation are located on the site, including Douglas Fir, Big Leaf Maple, Western Hemlock, Western Red Cedar, Alder, as the dominant species of the native coniferous /broadleaf mixed forest. The site appears to have undergone additional clearing since the original logging activities and, at the present time, a number of firs of the 8- to 14 -inch category and some larger Big Leaf Maples are scattered throughout the site in some cases in significant clumps.: The understory in- cludes grass, blackberries, salal, Oregon grape and other shrubs and grasses native to the mixed forest. The major groupings of trees are shown on the site inventory and site plan as well as the topographic survey. These mayor groupings and - significant specimens have been considers in site planning..: to preserve them. wherever possible. =' The site is typical of many of the plateau regions above the Green River Valley, and a site visitation by a land- 49 .• . scape architect did not find any rare or endangered-. species occurring within the proposed development site. b. Impacts Some portions of the site will be extensively cleared for development of the project, namely the western portions with those areas shown on the site plan to be retained.' These areas contain large Firs and Maples. The vegetation around the level areas of the two ponds will be retained as a part of those retention ponds. The project propo- nents, the architect, landscape architect and other con- sultants have expressed intent to preserve large trees within the development to the maximum extent possible. 7.7 - . Steep,slope areas,-defined asthose exceeding 25 per Cent,„., •77and-thOSe:areas-1Of 15 to TA will be preserved wherever possible including the natural . Vegetation in those areas.: It might be noted that from the inventories and visual surveys of the site, much of the significant vegetation viewed from below the site on 1-405 and other areas occurs in the steep-slope areas and will remain as a part of the visual amenity on the site. Covenants are proposed for those areas to remain open_ to • - prevent vegetation removal. Clearing and grading require- ments for construction will result in removal of vegeta- tion from some areas. 1 . r.. . • w' ,,-- flv Major buffer •zones of trees -W.]: Ohj the perimeter. of' the L, .... -_, . _. .. • •.• , • ..1,.- li,./tA, • _., ./V/± -i: Site, along-theridge• line and in the drainage areas will ;r , ,'1,,• ' /u / -• , - '..-:..be preserved. However, on the 2--- balance .of the site vegeta- b 1 .11 - • ■-- tion removal will range from 40 to 80 per cent of isolated [;j - • ' .c...' areas. Diversity of natural floral,species can be ex- pected to be reduced as a result of such a substantial reduction in the quantity of natural vegetation. 50 5. Fauna a. Existing Conditions The existing character of the undeveloped site offers limited habitat for large animals in the heavily urbanized area. However, rodents, such as mountain beaver, hare, mice, shrews and moles occur on the site. The drainage channel and bordering vegetation may attract some species such as racoon from adjacent wetland areas. In addition songbirds and some upland game birds such as quail frequent the site. No unique, threatened or endangered wildlife species are known to occur in the project area; however, encroaching suburban development is limiting the available habitat for resident species, particularly large mamiials or game birds. No fish are known to occur in the drainage channel nearby due to its intermittent flows and blockages at some downstream locations. c. Mitigating Measures Minimal and selective vegetation removal should be encour- aged particularly northerly of the ridge line, where the most significant area of natural vegetation presently occurs, as well as those areas around the drainage ponds. Replanting and landscape requirements should use native species and compatible ornamental varieties. Additional inventorying of vegetation should occur at the time of surveying for various buildings. Consideration should then be given to slightly altering the orientation or siting of buildings, parking, walkways and other devel- opment in order to save significant groupings of trees. . Impacts Substantial site clearing and the introduction of a large human population will have the most significant impact particularly on the southerly portion of the property. Displaced wildlife may try to relocate in adjacent for- ested areas or the valley areas nearby. However, since 51 incremental development throughout the area is reducing available wildlife habitat, adjacent areas can be con- sidered to be at their carrying capacities for wildlife. The result will be a net reduction in species diversity and the number of individuals of each species that will be present in the area. c. Mitigation Preservation of the steep slope, watercourse areas and pond areas should substantially preserve this habitat for species. The restoration of some vegetation in the area in the form of landscaping would provide a future habitat for those species which are compatible with an urban environment (i.e., songbirds, squirrels, etc.). The open space system will provide a corridor for the movement of animals between the park and open space area and other areas in the general vicinity. 6. Noise a. Existing Conditions The site currently contributes no measurable noise to the environment. Major noise factors in the area are the two major highways and their interchange. The interchange itself is 1/4 to 1/2 mile distant, while the roadway of Interstate 405 passes within 800 feet of the southwest corner of the site. This freeway alone has peak hour volumes that should generate noise levels above 70 deci- bels (dBA) at least 10% of the time (L10). This is sup - ported by readings of sound levels above 70 dBA at the south side of the Tukwila apartments, immediately west of this site and closer to the major interchange. This noise level is at or•above the level which Federal Highway Administration standards define as the maximum level acceptable in residential areas near highways. Local and Federal standards also indicate this as a level 52 :likely to cause annoyance and interfering with speech out of doors. The two houses south of the site on 62nd Avenue should be receiving average peak (L10) noise levels close to 80 dBA out of doors. Impacts The development will generate noise levels on and off the site due to traffic to and from the site. The single- family area, with access to the north, will generate only a small amount of traffic noise. The multi - family devel- opment, with 189 units gaining access to the south via 62nd Avenue, would raise the noise generated by traffic on that road alone by a substantial amount, - exceeding -10.' dBA."' " This is normally considered to be a significant' rise` in noise levels, causing annoyance. However, the potential receptor areas will already be receiving noise from the highways in excess of 70 dBA (L10),- and median noise levels (L50) substantially in excess of the 60 dBA stan- dard. The noise level at. 50 feet from 62nd Avenue, gen- erated by this project plus the San Juan Apartments and the anticipated project to the southeast, would probably . not exceed 50 dBA (L50). It will therefore probably not be perceived above ambient noise levels from the highway. Construction on the site will create noise peaks, with substantial use of heavy equipment, pneumatic tools and sane blasting to move a substantial amount of earth, hardpan clay and bedrock. Such equipment can generate noise levels of 65 to 85 dBA at 50 feet. The areas most exposed to noise impact from this site will be the Tukwila and San Juan. Apartments, plus apartments under construc- ==tion along the west %border. of . the property To the north is the Tukwila Elementary School playfield, which will receive less noise, as intensive activity will take place mainly on the southerly half of the site, behind the ridge dine. Noise peaks may be reduced by up to 6 dBA for each 53 doubling of distance from machinery, so that noise from the center of the site would be reduced by distance by 18 . dBA on adjacent properties. Earthmoving near the site perimeters will have the greatest impact. The construc- tion period is estimated to include less than three months of heavy earthmoving activity in each of the three phases. Thereafter, heavy machinery noise peaks will be reduced and replaced by general construction noise and trucks.. . Mitigation Construction noises will occur in phases at different locations on the site. At any time, the majority of the potential noise receptors around the site would be a substantial distance removed from the noise- generating activity. Further mitigation could be achieved by limit- ing heavy construction operations to normal working hours and by giving advance notice of sudden or exceptional noises such as blasting. 7. Light and Glare a. Existing Conditions None b. Impacts Traffic entering and exiting the site at, night could cast light upon some nearby residences from headlights. Some light will be visible from the residences themselves from areas off the site. � if I • " f ;' '„r_ V.w! ( c. Mitigaton Much on site light will not spill off the site due to topography and the vegetation being left. Proper orienta- tion of buildings and use of berms and landscaping along roads and entrances can minimize light spill off the site as well as between areas of the site itself. 54 8. Land Use In that the request is for a zoning reclassification this subject has been covered in detail in Section II -F - Rela- tionship to Existing Plans and Regulations. In addition the following conditions and impacts are reviewed. a. Existing Conditions The site is vacant with no improvements; some timber exists on the site, primarily 8 to 10 inch Douglas firs. In addition some Maples and Cedars of significant size are . scattered on the site. The site at present with its. R -3 and R -1 12,000 zoning could theoretically support 30 to 35 single family lots and 44 to 58 apartments or condominiums in a series of 4 -plex buildings. The former comprehensive plan called for multi- family on the entire site with no density clarification (i.e. adjac entF properties are Wand R-4)., , This plan was changed in 1977 and the present map and policies described in Section II -F will guide land use decisions and rezone applica- tions. The requested change in terms of density is summarized in . the table below. Table 1 Proposed Zoning Areas and Densities Location . No. of Zone on Site Units Zoning Comprehensive Acres DU%AC Code Plan R -4 .Southwest . 134 6.16 R -3 South of 32 3.15 Ridge Line R -2 Northwest 18 2.23 R -1 Northeast 10 3.19 22.70 43 17+ 10.20 18 7 -16 8.07 10 7 -16 3.14 3 -5 1 -6 • The resultant site coverage with buildings is 17.8% and other impervious surfaces 30.0% for a total of 47.8% site coverage. 52.2% is in open space and landscaped areas. b. Impacts The 14.7 acres of undeveloped land will be committed to multifamily and single family uses, plus a 2.56 acre open space tract. The proposal would provide a range of 3.19 to 20.70 DU's/acre, averaging 13.19 units/acre. 'Alterna-4 TIEkres would reduce'or increase this densitYndASsociated Impacts. - j1/1 , 14t c. Mitigation • • a „ suitants. • • • • z - nsive-Piat • designatims-for-the-the-s-iter-W4e-goals-aqd-patirK.,s—af -the-Plag-aQd-f=m4des-tor-oend4t4ens-te-ameklorate-4deatr • i4ied-impate4s. The declining densities of the Planned Unit Development approach provide a variety of housing/ opportunities while providing transition zones to exist adjacent development as well as within. the site. 9. Natural Resources A. Existing Conditions No natural resources are on the site; other than trees, and none are being consumed. b. Impacts PA • '11 :pock' and topsoil on the site will be relocated on the site, so that importation will be limited: Rood, cement, asphalt and energy resources will be utilized on the site. The project will not require any unusual amount of these 56 .�: :. City as a base. The 1978 figure has not been certified by the State of Washington. Table 2 Rbpulation and Housing -- Tukwila Single- 5+ units/ Total family Duplex Triplex 4 -Plex Bldg. 1977 Census 1685 574 22 1978 Estimate 1693 578 22 Added by Project (Est. 1982) As % of 1978 199 10 18 11.5 1.7 81.8 3.0 3.0 Est. population /unit. (2..5 Est. population added 0. 4481` 30 54 70 300 .. 3 48 1038 3 52 1038 32 139 61.5 12.9 I.7 /, .2 .2 2.2 �. The total population impact is estimated at.498persons, assuming no vacancies. Actual population will probably be lower, with some vacant units. A statistical average for family size has not been established for condominium units in this area, so the figures for the single - family and duplex units were the average for owner- occupied units in the area(currently mostly in single family dwellings) and "`the balance at the average for renter - occupied dwellings. Relating the proposal to the existing housing mix in Tukwila, the project is adding proportionately less to the supply of .single - family housing and to large multi -unit structures. It is adding a far greater proportion to the currently low supply of two- and four -unit structures. Though the trend towards multi - family structures in. Tukwila is being continued, the condominium ownerships will tend to increase the proportion of owner - occupied dwellings in Tukwila. 58 c. Mitigation The population and housing impacts will be spread out over three years. 3. Transportation /Circulation a. Existing Conditions Area Streets The project area is touched at the northeast and southeast corner by existing developed roadway. A right of way along the easterly boundary in the 62nd Avenue South alignment is unopened from South 151st Street at the northeast corner and South 153rd Street at the southeast corner. South 152nd is open to a point approximately 200 feet from the west boundary line of the proposed devel- oiled:. At one time South 152nd Street divided the property between lots 8 and 9 but was vacated several years ago. Access to the northeast corner would be to a well - improved right of way with curbs, gutters and sidewalks that joins 65th Avenue South, carrying traffic from that area south to Southcenter Boulevard and north to the balance of Tukwila, the Fire Station, Police Station, schools and other facilities. However, as much of this area is single- family, this proposal limits access to this area in order to minimize impacts on that street corridor. The southeast corner, 62nd Avenue South, is an improved two - lane road of approximately 18 feet in width with 3 to 4 foot shoulders and open drainage ditches. The roadway is proposed to be developed at its southernly terminus along the last 200 to 250 feet to serve the new City Hall pre- sently under construction. South 153rd Street south of the San Juan Apartments (i.e. at the southeast corner of the project site) is an improved two -lane private road. Some: visibility problems .occur at the intersection of South 153rd and 62nd Avenue S. Driveway cuts to serve the subject property will consider the elevation of this cor- ner. Any future development of the property to the south- east of that intersection, i.e. a portion of lot 16 of 59 Interurban Addition known as the Black and Caldwell prop- erty will be required to dedicate right -of -way and widen both 62nd Avenue S.E. and South 153rd. The . development of the proposed project, if concurrent with that of the Black property and of portions of lot 11, may provide opportuni- ties for joint efforts to improve 62nd Avenue South from the conclusion of the city's improvements to South 153rd Street. To the west of the subject property South 152nd Street is . opened to serve existing and developing apartment com- plexes in the area. The existing facility and proposed improvements have been the subject of significant con- sideration and discussion by adjacent property owners, the city and the county. This road is narrow with no curbs, gutters or sidewalks and is heavily impacted by existing development. The proposed project would have an outlet to 152nd Street; however, it would be proposed only for fire - lane access with a break -down barricade. The site planning and circulation plans call for carrying all of the multi- family dwelling units' traffic to the southeast corner where it reaches theexisting arterial ( Southcenter Boulevard) and Freeway interchanges with I -405 and I -5 by the most direct route. Transit Metro transit provides several routes linking Southcenter Boulevard, Southcenter Shopping Center and Tukwila with other valley communities such as Renton, Kent, Auburn, nearby facilities such as Seattle- Tacoma International Airport and employment centers as well as downtown Seattle and east side communities such as. Bellevue. Several tran- sit lines serve Southcenter Boulevard and Southcenter, within easy walking distance of the proposed project. 60 b... Impacts The proposed development is projected to generate approxi- mately 1,234.vehicularltrips per day. See Appendix C. The" impaCCOn. South reet'..from 10 family dwelling units, in a worst case situation assuming 10 trips per :household per day would represent 100' trips_per day. .- Assuming the worst case situation of 20 per cent of the trips during a peak hour this would represent 20 trips or one every 3 minutes. Other times of the day would average 5 trips per hour or one every 12 minutes, assuming all trips occurred in a 14 hour time period. The internal circulation system of the project will carerdniCifiF737 • through the 4-plex area and through the more dense por- tions of the project to 62nd Avenue South. These traffic impacts are projected to be, at 6 ADTS per dwelling unit, to be approximately 1,134 AIM. This traffic as it .is carried down 62nd Avenue .South to Southcenter Boulevard should have a minimal impact on the carrying capacity of • Southcenter Boulevard and re resents a 10 percent increase on that.facility. Avenue S. and at the point combine with city hall traffic. re anticipated on 62nd here those traffic flows At present the adjacent San Juan Apartment development and additional units could generate in the vicinity of 240 to 300 Mit. Proposed developments on the Black property could generate 300 to 600 ADIS. Of those instances some of that traffic may choose to utilize South 153rd Street ZAST. to join 65th Avenue eetatrteeet of those developments. This assumes a 50 per . cent traffic split each way then half of the traffic generated by those-two projects would be car- ried on 6261. Avenue. South:._ The remaining property that would be available for development of a significant size is lot 11, presently owned by Mr. *-14.-, The resultant development level on that site is unknown at this point; however, assuming that this property was developed at 18 61 If further studies show a need for improved traffic con- trol at the intersection of =Soutn.�_:62rid_ f and. Southcenter Boulevard, installation of those facilities may be war- ranted. Transit Car pooling and the use of Metro services promoted through literature in the condominiums' offices and recreational facilities could reduce peak hour and average daily traf- fic generation for the development. 4. Public Services. a. Existing Conditions Fire Protection The proposed development is in the City and would be served by the City Fire Department... Tukwila has two fire stations, one in Andover Park which s�rves the industrial area and one at 59th Avenue South andj147th Street. Esti. rtG ` :mated .response time_ .would be. l 0 to 2 5 minutes . `to . the" southeast corner and 3.0`to;..4.5 minutes to the northeast . corner of the- proposed project: . _ Emergency medical aid vehicles are available at the liik- wila City. Hall site. Thesite plan has been designed to' -provide for emergency vehicle access:` to the entire site Ts from the.. northeast or. from the -west 'over- improved one -lane "roads ,:that : -Would serve I-these vehicles.;_ in an emergency M situation •if_the southeast •corner access was blocked., . Police Protection Police protection is located at the same site of the fire station near the old city hall. The Tukwila Police De- partment patrols and responds to emergency calls in the vicinity of the proposed project. The ratio of,police officers to�-population in the- City of Tukwila is presently at or slightly below the national - average for a;, city.:- of- s= 63 Schools The proposed Northward Development project is within the attendance areas of South Central School District. Tuk- wila Elementary School is contiguous to and directly north of South 144th Street. Junior and Senior High Schools are within a walking distance of 10 to 20 minutes via a free- way overpass, but students from the proposed development would be provided bus service to the junior and senior high (Source: South Central School District, Transporta- tion Services, personal communication by telephone con- versation). The capacities and ,present enrollment of the schools . leaves scene spaces in each which would adequately handle the projected enrollment levels of this project. • / 7 Southgate Elementary School is scheduled for closure this p (r` f4 V Gf / year due to falling enrollment. Total elementary enroll- ment for the 1978 -79 'school year is estimated at 827. .. This will be handled by the three remaining elementary schools, with a combined official capacity of 1,025. "Comfortable" capacity, reserving rots for music and remedial reading, is 875. School enrollment has been consistently dropping in the district, due to changes in resident characteristics in the area, and the static housing supply. The annual enrollment in 1979 -80 is expected to equal the previous year, and a climb in enrollment is expected the following year. is is the yea when enrollment may be expected due to this project. "Comfortable" capacity is expected to be reached in the 1983 -84 school year (School District estimates). Parks and Recreation Parks, recreation and open space areas in Tukwila, in particular around the Tukwila Hill area, include 5.3 acres 64 at Tukwila Park adjacent to 65th Avenue South, a 52 acre regional King County.park along the Green River near I -405 and Foster Golf Course and a- 56 acre parcel along• Green -. `River- near Interurban- Avenue _ ,',School playgrounds_ provide ;��;/ T I • additional active recreational area and the undeveloped areas in portions of the city provide passive open space -r areas. However, within the city limits of Tukwila there are only 6.3 acres in city ownership used for park or recreational purposes, somewhat limited for a city of this size. Additional open space and recreational facilities would compliment that limited city resource. Maintenance Roads and storm drainage systems in the vicinity of the project area are presently maintained by the city of TUk- wila. The city and Metro (the Municipality of Metropoli- tan Seattle) maintain sanitary sewer systems. The water system in the area is maintained by the city and utilizes City of Seattle water. Impacts Fire Protectio_^. Approximately 250 fire and aid calls per year are gen- erated per 1,000 residents in the Tukwila area. Tbtal population of the proposed development is projected to be approximately 450 to 500 persons. Therefore approximately 120 fire and emergency calls per year may occur from the project area. In fact, fire calls will probably be much lower than average in the new buildings, with required fire safety devices. Service for the development is not expected to have any adverse impact on existing manpower or equipment. Police Protection Residential uses have a moderate impact on police pro- tective services in the form of burglaries and emergen- 65 cies. Non- emergency calls are perhaps the most time - consuming requirement of multiple - family developments. The circulation and street configuration can both posi- tively and adversely affect police emergency response time. Discussions with the Police Chief indicate that through circulation is desirable in order to serve emer- gency vehicles and promote quick response time. However, through circulation can provide the adverse element of allowing burglars in adjacent property more direct and . unimpeded escape routes when pursued by police personnel.. This proposed development is not expected to directly result in the requirement for additional police personnel or equipment. However, the cumulative effects of in- creased development on this hillside may necessitate addi- tional expenditures in the future. Schools Due to the phasing of the proposed project, maximum school impacts are .not expected until the 1981 -82 school year, when school planning presently anticipates growth. At a "worst case" estimate, this proposal could generate 50 elementary school students, bringing the elementary schools to their "comfortable" capacity, as estimated by the district. Other developments could take elementary enrollments higher. • '.Ihe District's strategy at that time could include reopening Southgate Elementary, expanding another school or going beyond "comfortable" capacity. The predictions for secondary - school enrollments were not carried beyond cohort-survival projections. It is. assumed 'that up to 50 students could be added, with some impact on the capacity of those schools. Parks and Recreation • Residents of the proposed development could be expected to • utilize the park and recreational facilities in the city 66 and in the Green River valley, playgrounds, and to a lesser extent the golf course, fishing opportunities in the Green River Valley and nearby lakes as well as other community facilities of adjacent communities. Maintenanc The proposed evelopment storm drainage fa lities velopment would have of surfaces, clea rng o tenance oy-s of rm drainage would have privafe roads ands j l for which-the owner enance responsibility. Repair , ilution control devices, main- ®� utilities on site would be of the de- "oft required of the developer and fti ure home owners. Mitigating Measures Police Protection The police department should be provided with a copy of the final approved development plan locating new street addresses in the project area. Schools rding chool --of icia s ht. e junior hig could . er7 -• in - • • - • entary, n ii a mots ce the project-. Parks and Recreation The development proposal includes 2.56 acres of open space facilities with an additional recreational area including a building, two tennis courts, a swimming pool and large areas of trees and open space are scattered throughout the site. The trail system would provide for jogging, walking and passive recreation, mitigating the need for these facilities in adjacent areas. Maintenance Stringent storm drainage design requirements could reduce maintenance. Regular maintenance of the privately owned 67 drainage facilities could reduce maintenance required for public portions of the system. 5. Utilities a. Existing Conditions Energy. Puget Sound Power and Light would serve the proposed de-. velopnent with electrical energy. The proposed condomin- ium units would be "all electric" and are estimated to use approximately 2,000 kWH of electricity per unit per month (conversations with Puget Power). Use of natural gas may be considered for heating the swimming pool. The gas mains, according to the City Public Works Department, are available at the southeast and northeast corners of the property. Communications The project area is served by Pacific Northwest Bell and hookups are available' at the southwest and northwest corners of the property. Water The city of Tukwila provides water service for the prop - erty as shown in Figure 12. Water is available at the northeast corner through an existing 8 -inch main located in the 152nd street right of way. A 6 -inch water main is . also available, presently serving the Tukwila Apartments at the southwest corner of the site. The Public Works Department suggests linking these various water mains to provide continuous loops, better water service and better pressure for fire - fighting purposes. Sewer The City of Tukwila and Metro provide sanitary sewers in the vicinity of the project. An existing 8 -inch sanitary sewer is at the northwest corner. An existing 8 -inch line 68 serves the new City Hall property on 62nd Avenue South. The latter line would be required to be extended as a part of 62nd Avenue South improvements, as shown in the sani- tary sewer system, Figure 13. This proposed sewer improve - ment would serve three major properties in the area. Storm Sewer No publicly owned storm drainage system exists in the project area at the present time. Runoff from major por- tions of the site travels to the east down an existing drainage channel past the new city hall and under South - center Parkway to a point where it joins an existing stream bed that flows easterly along I -405 into the Green River. Peak flows from the project could be taken care of in an improved drainage system along the improved 62nd Avenue South right -of -way. b. Impacts Assuming that the proposed dwelling . units will be all electric and will require approximately 2,000 kwh of electricity per month (average), implementation of the project would result in the increase in monthly electrical requirements for the site approximately 398,000 kwh at full development. According to Puget Sound Power and Light, they have adequate energy resources and equipment in the present service area and would expand its local services as necessary to accommodate future growth. Communications • Telephone communication service for this development is estimated to require 254 cable pairs. According to Pacific Northwest Bell, this can be accommodated within existing systems. 69 rG FIGURE 13 11,H SANITARY SEINER SYSTEM Isl)• rc 1 , tz-/ , // • ((.(/ / / // ) S 47" 57 ■ 11 ■ ? sEwmfuw• '\`\\ \ l thCLE fAmIC 1 Alo DaPaXP . ,.--_/`N ' } • 7AS.161"'Sr " \Cj • k Aeme via 015014R4E•PopeAt ' "V\ • \ c. \ \ .•-f (\\ ( r %.. \Ni , i ' ‘ -4 ‘, ,1 .\z‘ \ \ - \ t k::: foftael AID 6:\ -- j emml maw 0, om.400 u , 14,4 LAWS, t ' . -.........1., i \\ \ — . . ' . . \ . \ • • . ' ' r17:V \ 1 .45S.T • gip* ) =CD . 1 . . . 1 a\ Fetzig,onF.;a3,42„ .,.- 'v- \A"'"1"1"3"70"62"° AYES INFROyeteitTS) PetY05e0 11'544 SEWER )\-\ / _J 1TE , • `MAD 4 —,-- ASSOCIATES ---- .70 Aar? CatSar..t764 7/4frrI alY PAL / & N /el/MNS fekeR MAN / 0 00 "10 •Co Water Implementation of the proposal will require construction of water mains through the site linking existing facili- ties at three corners and the west side of the site. Water consumption within the project area will increase usage in the area approximately 30,000 gallons per day. The increased requirements for water services is not expected to have an adverse impact on existing water sup- ply or the proposed system through the site. Sewer The proposed development could be expected to generate approximately 20,000 gallons of sewer per day (see Appendix C). This increase in sewage flow from the project area is not expected to have an adverse impact on . sanitary sewer in the vicinity according to the public works department. Storm Drainage Drainage within the proposed development would be col- lected in surface collection systems including retention areas and released at a slower rate into existing drainage channels or in improved sanitary sewer main along 62nd Avenue South. c. Mitigating Measures Energy Discussions with the architect indicate that energy con- servation measures (as well as noise limiting measures) such as weather stripping, wall ceiling and floor insula- tion and insulated windows will be provided in the pro- posed dwelling units to reduce heat loss. Common wall construction is proposed .for most of the units and will reduce energy requirements for residential heating. 71 Water and Sewer The installation of water saving devices in new dwelling .units could reduce water consumption and sewerage flows. 6. Aesthetics a. Existing Conditions The natural condition of the site with extensive tree cover and other vegetation provides a visual amenity to the Southcenter area, adjacent properties and the entire . south face of Tukwila Hill. A small, shallow, year -round stream . meanders through a portion of the site and along its easterly perimeter. The topography of the site, its location near -a school and other factors make it one of the more desirable undeveloped sites in Tukwila. Many portions of properties around the site particularly on the west and south have been almost totally cleared of vegetation making this site an unusual one with only the site to the southeast and some to the northeast in similar.. condition. Impacts Approximately 50. percent of the site would be developed with condominiums, parking driveways, trails and other facilities. It would have an impact on views to the site, particularly on views from Southcenter Boulevard and properties to the south, west and east. A more detailed analysis of this impact is contained in the graphics that follow this section. c. Mitigating Measures . Retention of natural vegetation to the maximum extent possible and generous landscaping can reduce the impact of hard surfaces (roads, fences, buildings) and preserve a certain degree of the forest character of the site. Build- ing designs are proposed that take advantage of the slop- ing of terrain on the site to avoid the repetition of 72 EMI Oa Mai OMR 110 110 110 180 170 150 110 010 110 170 130 110 110 010 110 170 -� 150 0 EAST - WEST CROSS SECTION EAST WEST CROSS SECTION NORTH - SOUTH CROSS SECTION FIGURE 14 V —ST �xfOz3 13A31 N3Hh01 ~� In®a.ILWAM —DIM EI®u - 131131 1tl0d14V0 13A31 N3ddf 31V1d 'd0 day 1 n0-,I .,,b /I Aims _11. •I ,_ �1 ia I!!IH!tl9ll!! !itl!!!n :. ° ' " �!�!!!1!!�!!! )Llntui!iu!g 1 NE 1111-1--ik g l.:1■ �mi g■■ , t y , `1 am- M11 MEI M B . � 0 JffiI1IIIIUII H III aim TVPoCLL1L, PRON ,' ELEVATION ON ®L©® 04441 . Vn I'• o' COTWa*. 'C • UNIT 6UILPIN4 .6.4""19 CD:OtEDE EL EVAT0 ®N ®L ®0 PROW? ELEVATION tEl3LIEDEM 11 ea 2 eaakf I Vb. • 1'•01 srr>� ye • Ice, FIGURE 15 —C `cr;a21 Vega Ei 1 %311 OR ACE _.L 1 11 1111311111 Mfrn905r B - PR®Nn1Ti' ELMVAT IONI 1/4" Imo 1 111111 11111.1 1111 II 1111.x.11111 v l4ONO T' E3 - (RMAR? OmL G✓MQA'4'0®m 1/4 FIGURE 15 -B TOP OF PLATE 1• UPPER LEVEL LOWER LEVEL LIVING ROOM 1 • i LDINOV B ■ S00D01 0211.0 VL TO®OU 1/4" rectangular building facades. The large buildings have been turned at an angle to appear less massive from prop- erties to the west, south and east. The ridge line and existing vegetation have been used to obscure the common- wall developments from the northwest, north, and north- east. The architect has utilized existing topography and major groupings of vegetation wherever possible to nestle the buildings into the site. The four -plex and duplex town- house units will be incorporated into existing vegetation . using exterior wood siding with natural earth tones to be compatible with the site. Larger buildings will have some wood details and some stucco finishing. There will be extensive landscaping, rockeries and other facilities to provide a natural transition for the existing topography. In addition, screening easements, retention of the vege- tation through restrictive covenants and the use of . densely planted vegetation perimeters will be provided between different use areas proposed for the site. Archaeological/Historical Resources a. Existing Conditions A review of City planning documents, County planning docu- ments and discussions with State agencies uncovered no known archaeological or historical resources in the pro - posed project area. REMAINING ADVERSE IMPACTS THAT CANNOT BE MITIGATED A. Modification of the topography will take place on site to accommodate buildings and roads, requiring movement of a large quantity of soils. B. Storm water runoff will increase in quantity, except that peak flows will be lowered by detection facilities. Some increase in pollutants in the runoff will take place, including oils and grease, heavy metals, sediment and nutrients. C. Animal habitat will be removed as vegetation is removed from a large portion of the site. Only species tolerant of human activities will remain. Occupants driven from the site will largely perish. D. Residential uses will be established in an area subject to high peak levels of noise. E. The 14.7 -acre site will be committed to urban residential land use, at a greater density than under the existing. F. An increase in the potential population of the site, as a net effect of the rezone, of an. estimated 230,persons, an absolute increase, due to the projected construction, of up to 450 persons, over a three -year period. G. Traffic will be substantially increased on 62nd Avenue South, from the Southeast. corner of the site to Southcenter Boulevard, and increased by 10 per cent on Southcenter Boulevard, east of the overpass to'Southcenter. H. There will be a general increase in demand for public services, in proportion to the rise in population anticipated (about , 15 cent). 78 V. THE RELATIONSHIP BETWEEN LOCAL SHORT -TERM USES OF MAN'S ENVIRONMENT AND MAINTENANCE AND ENHANCED OF LONG -TERM PRODUCTIVITY The site would be irretrievably committed to urban development, in contrast to alternative housing or open space uses. This is countered by the fact that the site is surrounded on 2 -1/2 sides by. apartments, 1/2 side by single family and potential single family and 1 side by recreational uses and is in a municipality with utilities and. access on most sides. Urban growth will continue on the Tukwila Hill and the development of the site can provide a new form of site planning and design for the area while preserving some open space and being complementary to the goals and poli- cies of the city. The commitment of this site will decrease the likelihood of pressure for.more peripheral deveopnent_on agricultural land or other - -.open space.::..;_- VI. IRREVERSIBLE OR IRRETREVABLE COMMITMENTS OF RESOURCES The alteration from wooded hillside to urban residential uses isfor all practical purposes irreversible. The development of this site will consume energy throughout the building phase. The placement of streets, sewers and other utility lines and the preliminary development of resi- dential units will involve the consumption of concrete, metals and wood resources which will be effectively lost for other use. The infilling of the urban fabric here will decrease use of resources for maintenance over time by being integrated into an existing infrastructure near shopping and employment and by decreasing pressure for develoznent on the peripheral" areas of existin urban development.- 79 APPENDICES A. Soils and Geology - Consultant Report B. Hydrology and Utilities - Consultant Report C. Calculations for Analysis of Impact D. Project Statistics E. Miscellaneous Resource Data and Maps F. 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H O 0 ct 1--j .H Gt�� f:4 D(Dp0H0 ED Fj 1 -• 1-i 1�' Ot? H cI- 0) .0 w fu . 17 J) U) (0 ct 0 U) CD (D 0 ;�' p' ' S P, 0 • . jj H et , F-J ; �' . p., )•• Fj ct 0 i0 (1 0 0 c1• • _• i.S' (0 CD . ■ 0 0 • SU (b -C, !,� • (0 i 0 U) C' 1 0 (!) ), 1-1, P., 1'+) ''..t., t J c r• M! • m (. r •• ✓ ) D rn .. D- iJ a tJ v N z rl 0 z 00 co 0 • • • m • r) • z7 E rn rn n . r`1 7 `_ ] rid 7 • cv-N- . 3 Dril still Page 2 January 17, 1977 Robert W. Thorpe and Associates gravel. It is weathered in the upper two cr three feet. Except in-the upper few feet which have been weakened by weather and root action, sliding is uncom- mon, in till; and no signs of past sliding were noted. Expsures off the property to the souti and southwest indicate that-the till grades downward into a massive unit of relatively cleaner sand and gravel, also of glacial' origin. A small outcrorp'ing.of _ndesitic intrusive bedrock is exposed at the southeast property corner. Soil immedi- ately adjacent to the rock is of residual origin. As a practical matter, only the glacial.soil -will be of much relevance to development. No surface indications of adverse drainage conditions or seepage were noted. Except for possible localized horizons of perched saturation, true groundwater is , no doubt well .below the lowest property elevation. So far as 'the intended improvements are concerned, the most restrictive soil- related factors will be the moisture sensitivity of the till and .slope stability of any fills which Light be placed. To minimize those potential. problems, earthwork should be kept to a minimum, and it should be attempted only during the dry season. By virtue of its cohesion and gravel _content, till is not a highly erosive soil, although its impervious nature will cause greater runoff than from most other native soils. Temporary sedimentation ponds.vill be necessary during construction. Storm- . water runoff will be-regulated-after construction; the effects of- runoff will diminish over about a two -year period while the new flora is establishing itself. • Should City personnel or any other concerned parties have any cuestions• about this matter, please encourage • taem to give ne•a call. wfY=1F . .. " :_ • 9 (. ' ;; 11 .. f / JECT:�1'e �„".!: -. '.0. 1 i7 `'•,.:)1(;j";;1._ ∎- 4•'. } 4' ",=z- .< -<va ^. Yours very tru •Jame s N. Eaton March 29,1978 Mr. Robert W. Thorpe 815 Seattle Tower 3rd & University Seattle, WA. Subject: 15 -acre Tukwila P.U.R.D. for Northward Development Co. Dear Mr. Thorpe, The following pages contain the requested technical information on the hydrology, water system and sewer system for the proposed Tukwila P.U.R.D. Hydrology Existing Conditions - Stormwater runoff generated by the site currently drains in three distinct directions. The northeast portion of the site drains into a well - defined drainage swale. This swale, which also receives drainage from the developed area to the north, broadens to form a shallow pond about one foot deep on the east boundary of the site. It then runs from north to south eventually emptying into the I -405 storm drainage system. As well as conveying stormwater runoff the swale conveys a small base flow component of approximately 0.1 cfs which acts as the source of the shallow pond. The south portion of the site drains into the currently undevel- oped property to the south. There are no distinctive drainage swales in this area. Runoff travels essentially as sheet flow until it is intercepted by Southcenter Parkway and routed into the I -405 storm drainage system. A shallow depression which has a maximum depth of approximately 3 feet exists adjacent to the sita's west boundary. Approximately 2 1/2 acres of the site as well as 1 1/2 acres west of the.3ite (the only offsite area draining into the site) drain into this depression. This drainage is apparently the source of the standing water (which is probably seasonally intermittent) at the depression. Proposed Site Drainage - The existing drainage patterns at the site will be basically retained. Stormwater runoff from the north- east portion of the site (which is proposed for the least intensive . development) will pass through oil -water separator catch basins 846 - 108TH AVENUE N.E. 0 BELLEVUE, WASHINGTON 98004 • PHONE (206) 454 -0711 Page Two Mr. Robert Thorpe and then be conveyed to the existing drainage swale at the east boundary. As a result peak flow rates will increase in the swale. However at points A and B as shown on the Existing Drain -. age map, the peak 10 -year return interval flows should increase by only 30% and 20%, respectively (from 7.7 cfs to 10.1 cfs at A and from 9.9 cfs to 12.1 cfs at B). Due to.the relatively steep channel slopes the existing capacity of the downstream system should be adequate to accomodate this flow rate increase. Because of the more intensive proposed development of the south portion of the site, stormwater detention facilities will be provided to limit the 10 -year peak discharge to the south to approximately the existing 1.2 cfs 10 -year peak flow rate. Discharge from these facilities will probably be made into a storm sewer line which should be built at 62nd Avenue South in conjunction with improvement of that street to facilitate this and neighboring developments. Such a storm sewer would then discharge into the 1 -405 system at Southcenter,Parkway. The depression along the west boundary will probably be devel- oped as a shallow pond .for use as an amenity to the project. However runoff from a portion of the area currently tributary to this depression may be routed into the detention facilities at theouth portion of the site. Water System City of Tukwila watermains currently exist at or near all four corners of the site. The supply source of all of these mains is a 16 -inch diameter City of Seattle watermain. Therefore the estimated average daily residential consumption for the site of 73,000 gallons (based upon 194 units, 2.5 occupants per unit, and 150 gallons per day per occupant) is not expected to adversely affect water supply to other City of Tukwila users. Looping of some or all of the existing systems may be required for provision of adequate fire flows to the upper elevations of the site. Such looping would also benefit nearby properties by increasing available fire flows in the existing mains. Sanitary Sewer System Sanitary sewage generated by the proposed development will drain into two different sewer mains. The main at the intersection of 62nd Avenue South and South 151st Street will receive sewage from the proposed single family and duplex areas of the site. The average daily sewage discharge from this area is estimated to be 7000 gallons (based upon 28 units, 2.5 occupants per unit, and 100 gallons per day per occupant). Page Three Mr. Robert Thorpe Sewage from the four -plex and apartment areas will gravity to the south. This will necessitate extension of the existing sewer main on 62nd Avenue South up to the Southeast corner of the project. Average daily discharge from this portion of the development is estimated to be 41,500 gallons (based upon 166 units, 2.5 occupant per unit, and 100 gallons per day per occupant). This additional sewage is not expected to create sewage flow capacity problems in existing downstream mains. Sincerely, TRIAD ASSOCIATES, INC. David L. Halinen, Project Manager DLH:cg !,,,:-. • PROJECT STATISTICS LOCATION: CITY OF TUKWILA CODES: TUKWILA ZONING ORDINANCE AND UBC 1973 EDITION SEISMIC ZONE: III FIRE ZONE: III OCCUPANCY: H— MULTI — FAMILY CONSTRUCTION TYPE:. V —N, & V —ONE HOUR IN R -4 ZONE EXISTING ZONING: R -1 PROPOSED ZONING: • ZONE R -4 R -3 R -2 R -1 (9,600) TOTAL SITE AREA SITE COVERAGE: MULTI — FAMILY SINGLE FAMILY TOTAL AREA 268,615 S.F. 137,308 S.F. 97,101 S.F. 138,753 S.F. 641,777 S.F. PAVING COVERAGE: ROADS, DRIVEWAYS, & PARKING AREAS WALKS & PATHS POOL & PATIO TENNIS COURT OPEN AREAS ACREAGE 6.16 3.15 2.23 3.19 14.73 ACRES 99,025 S.F. 15,000 S.F. (APPRX.) 169,000. S.F. 14,720 S.F. 2,700 S.F. 7,200 S.F. 193,620 S.F. 334,132 S.F. D.U. /ACRE 22.70 10.20 8.07 3.14 GREENBELT AREAS 111,400 S.F. 2.56 ACRES (NATURAL VEGETATION. RETENTION) UNIT STATISTICS ZONE R -1 R -2 R -3 R -4 R -4 R -4 R -4 UNIT TYPES SINGLE FAMILY A DUPLEX TOWNHOUSES B 4 —PLEX TOWNHOUSES B TOWNHOUSES C 2 —BR. FLAT D 2 —BR. FLAT E 2 —BR. FLAT 30.0% 52.2 %. SQ. FOOTAGE UNDETERMI NED 1,502. S.F. 1,231 S.F. 1,231 S.F. 1,077 S.F.._ 1,074 S.F... 995 S. F. b NUMBER 10 18 32 6 48 28 57 199 APPENDIX C Calculations for Analysis of Impact Trip Generation Proposed Units ADT's/Jnitl Average Daily Traffic 10 single family houses 10 100 18 duplex townhouse condos 6 108 32 fourplexes 6 192 139 condominiums 6 834 1,234 Population/Housing2 Single - Total family Duplex Triplex 4 -Plex Bldg. 5+ units / 1977 Census 1965 574 22 3 48 1038 1978 Census 1693 578 22 3 52 1038 Added by Project (Est. 1982) As % of 1978 199 10 '18 11.8 1.7 81.8 Est. population /unit 2.5) 3.0 3.0 32 61.5 139 13.4 2.2 2 Est. population added 498 30 54 70 306 Projected Student. Population Units 189 condominiums 10 single family ay 450) lInstitute of Transportation Engineers, 1976. 2City of Tukwila census data. Projected Student Population - School Ages 60 -100 students 30 -50 50% elementary 30 -50 50% junior /senior high Water Usage Estimated to be approximately 150 gallons per day per resident.3 Sewage Flow Estimated to be approximately 100 gallons per day per resident. Projected Resident Population: 450 persons x 100 gpd = 45,000 gpd Residential Electrical Requirements Estimated on the basis of approximately 2,000 kwh per unit per month for all - electric units. (Puget Power:- phone conversation). Proposed: 199. units x 2,000 kwh /unit /month = 398,000 kwh /month Residential Communications Requirements Estimated on the basis of 1.25 cable pairs per multifamily unit and 1.75 per single family unit (Pacific Northwest Bell, March, 1978). Proposed: 189 units x 1.25 cable pairs /unit = 236 cable pairs 10 units x 1.75 cable pairs /unit = 18 cable pairs Total 254 3Sources: Survey by R. W. Thorpe & Associates and engineering firms (February 1978), Triad Associates. BUILDING AREA CALCULATIONS BUILDING AREA CALCULATIONS BUILDING 1: BUILDING 2: 4 B UNITS @ 1,231 = 15 E UNITS @ 995 = 8 D UNITS @ 1,074 = CORRIDORS & STAIRS MECH. & STORAGE _ TOTAL 2 B UNITS 8 1,231 .15 E UNITS @ 995 = 8 D UNITS @ 1,074 = CORRIDORS & STAIRS = MECH. .& STORAGE _ 4,924 •14,925. 8,592 3,036 ' 420 31,897 S.F: 2,462 14,925 8,592 3,036 1,380 TOTAL 30,395 S.F. BUILDINiG 3: (UNDER BLDG. PARKING EXCLUDED) 12 D UNITS @ 1,074 = 12,888 27 E UNITS @ 995 .= - 26,865 CORRIDORS & STAIRS = 6,206 MECH. & STORAGE . = 3,600 -TOTAL .18 C UNITS @ 1,077 BUILDING 4: BUILDING 5: BUILDING 6: BUILDING 7: BUILDINGS 8 THRU 12: BUILDING 13: BUILDING 14: BUILDINGS 15 & 16: 12 C UNITS @ 1,077 :4 B UNITS @ 1,231 RECREATION BUILDING • 49,559 S.F. 19,386 S.F. 12,924 S.F. 4,924 S.F. . •. 1,300 S.F. 4 B UNITS @ 1,231 S.F. = 4,924 .. 5 X 4,924 = TOTAL 24,620 S.F. 12 C UNITS 81.1,077 12,924 S.F. 6 C UNITS 0.1,077 6,462 S.F. 4 B UNITS @ 1,231 S.F. = 4,924 S.F. 2 X 4,924 = TOTAL 9,848 S.F. BUILDINGS 17 THRU 25: 2 A UNITS@ 1,502 S.F. = 3,004 S.F 9 X 3,004 = TOTAL TOTAL GROSS PROPOSED BUILDING AREA ' 0 (NOT INCLUDING SINGLE FAMILY) . 27,036 S.F. 231,775 S.F. . - . ... • ...... ..• Census Tracts & fleighbo'rhoods. 711ERSOLA [PT.&INGERM &Ran, ,c3< IIII MIT11.11 ?LUNING coon= HIS I FIGURE. III -6: CHARACTERISTIC • CITY OF TUKWILA REMAINDER OF PLANNING AREA • TOTAL: TUKWILA PLANNING AREA Total Population: 1970 3,496 18,67 22,168 Total Year -round Housing Units 1,669 6;817 P 8,486 Total No. Singe- family Units 607 J.6 4,496 5,103 Percent Single - family* 36.4% / 65.9% 60.1% Number Owner Occupied Units 540 3,866 4,406 Percent Owner Occupied* 32.3% 56.7% 52.0% Median Value /Unit - ' \, - -. x122,800 $20,700 $20,800 Number Renter Occupied Units, `•f 804 2,153 2.957 Percent Renter Occupied* 48.2% 31.6% 34.8% Median Contract Rent % $132 $119 $121 Source: 1970 U.S. Census of Housing *Percentages are based on the Total Year - round Housing Unit column. • r The external analysis showed that the Planning Area as_ a whole was - comparable yin characteristics to the other Green River - Valley cities as . well as King County. Figure III -7 depicts the number of'single- family dwelling Anits as a percentage of the total number of year -round housing units it7 each census tract. The dotted horizontal line indicates the percentage of the Tukwila Planning Area as a whole; This graph clearly indicates the extreme•differences between certain areas within the Planning Area with respect to the general makeup of housing to be found. While the Planning Area as a whole maintains a 60% rate, tract 263 and 283 are 89% and • 85% single - family housing structures, respectively. In extreme contrast, only 38% of all the year -round housing units in tract 262 are single- family structures.. Tracts 272, 284 and 288 are comparable to the median level indicated for the Planning Area. 7A Tract 272 is highest at 18 %. Tracts 262, 263 and 282 are at a relatively average level while tracts 283, 284 and 288 are comparatively lower than the remainder of the Planning Area. HOUSING CONSTRUCTION: PAST, PRESENT AND PROJECTED TRENDS Ideally, this section on housing construction trends should invcsti.gate past trends of residential construction for the entire Planning Area However, insofar as much of the Planning Area is located within King/County and the pertinent data for that. area is not available in the form necessary .to.accom- plish.the ideal, this section will focus on residential trends within the City of Tukwila alone. , . Construction of single - family housing in the City of/Tukwila has been quite low in the rece st. However, prior to 1969, a relatively higher stable construction rate wa experienced in terms of new single- family residential units. This fact is born out. in Figure III -16 which portrays the number of new units constructed each year. Figure III -16 6 1. NUMBER NEW SFD'S, BY YEAR, TUKWILA 24 22 20 18 16 14 12 10 8 6 - 4 2 . 58 59 60 61 62 63 64 65 66 67 68 ' 9. 70 71 72 73 74 75 Source: .Tukwila Building Department Records. As pictured, new unit construction fell off markedly in 1969 and has remained at a level of less than four new units per year since that time. It must•be kept in mind, however, that during the period from 1958 through 1968, the Puget Sound Region experienced a booming economy both in the lumber and aerospace 81 iuuur� U;.L1\ f •CDTV .-IvrIAVNLIA ou a n 1 r� .,.,.ate • Apartments 8 V om enica Apartments 9 S thcenter Court Apartment 10 Vi e wcrest Apartments 11 Hi lcrest Apartments 12 M lecrest Apartments 13 ( ) 4 -unit Buildings 14 ' T U kwi 1 as Apartments • ts 3./Lr. 47 oi The density (number of apartment units per acre) of these multiple- family developments vary greatly from 16.5 units per acre to 41 units per acre, with an average of approximately 22 units per acre. The following table is a compilation of the density of various apartment complexes within the City limits, along with other relevant data: 1. Name: Zoning: Date built: Units per acre: 2. Name: Zonin : Date lt: Units' pe \acre: 3. Name: Zoning Date built: \ Units per acre: Name: Zoning: Date Built: Units per acre: . Name: Zoning: Date built: Units per acre: 6. Name: Zoning: Date Built: Units per acre: 7. Name: Zoning: Date built: Units per acre: San Juan Apartm R -4 1966 16.6 s Canyon Estates R -4 and RMH 1967 24.9 Sou hcenter Apartments RM' ],967 5.8 Source: Tukwila Building 1 Village Green Apartments M -1 (allows R -4 density) . 1967 26.9 Terrace. Apartments .13737 -56th Place South 1968 .35 \a Vista Apartments. RMH' 1959 35.k, . • Stardust,Apartments RMH 1970 41.0 . �.. Department Records. It appears from the above that.the density of units per acre is increasing from a low of 16.6 units per acre in 1966 to 41.0 per acre in 1970. The following Figure indicates there is undeveloped multiple - family zoned land available within the City of Tukwila: 45 LAND USE Q UAMTIHUAT ION -CIT' OF T {WILA, 1975 TOTAL ACRES = 2._3g9„1 (3.67 SQUARE FILES) :859.8 :.56.5 323.0 1758.7 124.J 61.2 3A6 443.5 46.6 11.8 112.8 135.4 .c 5.0 Z.8 23.5 11.1 14fL.9 1173.0 265.5 . _ 7 , , 1 1 EX;i5E1 PLAN NED FPCALITY (LANE CURRENTLY IM PUE-3LAC. C:M/NERatil P) . ISMOACICI 3.-4 1 =L-M EXIST I NG- FACILITY FRO FOS ED FPC1LITY (LAND ACAU1SiT I ON N Fr_Fca....SAP.Y) 4 L j ,....,... _ASO e _ _ tazo 1.11.113.1.1Clituural.,71.3asu 1. +vine •■••••■■■•••nr. 8..t ENE-AL PARK G. OPEN SPACE PL tfrumwoLta PLMEN© &NE& mr;\ C' (-2 c • . J ■■•■••••■■■•■••••. Environmental Factors' 1 Factor 2 Factors 3 actors ors yap VON am__E 111111111IIOII UIIIOtt1t�1 t1111111t11111N1111I1 U111II111 11111115 E T S V ALLY .:elm • TAe Enrtra. o wlrrn. t)rpic unstable Ms sap •as ; one another br darker areas e IMMO r A e pi-L&K.'kume Endeslc co gM ) ware critical A larger E.: rir Earelands, r- fiCO' HIGHWAY 99 O' - �= -� 7:1404; `'� - .:Il . r� Y 11r pn ' ,`0",%*rilt��!r ti IU''j '4' _ i 010 � ,, : a PLATEAU v VALLEY �, LO ND SUITABLE FAR R�IDENfnAL, STEEP SLOPES MAKE LEVEL SLOPE IS ESPECIALLY SUIT RECRERT1ON,q� ANID COM- THIS;ARFA GR`:ERPLLY ED FOR INDUSZRIALAND AGRI- MEI2ClAL_ LF-E . / UN° 7"ABLE FOR URBAN CULTURAL USES. it USES, =,LOC.AL.IZ.ED FIAT: TEJ R� .AS CAN BE DE V E L O P E P RDR R E S i D 15J - / T 1 gEc E noN.pLUSE'S '. f YSIOGRAPH I G . SECTION • r �. ,Figure I -4. Physiographic Areas: Plateau, Valley Wall, Lowland. • / • >a4 13 LAKES&RIVERS un MARSH STREAM ABOVE GROUND STREAM IN PIPE "2/1/1.414 100 00°°1't 11-5 HY li'UNN10 PLAHHINO . ananzemu=a=thatratmatteartanaurc.u.2.....”..,=.4;:=77: ---• '""TnTITTPTottoTORPOO-, uutflhtIL S2GE. KNOL1— L..MOOTTP PA PHYSIOGRAPHY TNON'WIL& PLARMIKO &NE& VW WAN lativ tal, / r - - - .„...:>TPC PORT ,.• • J Park eau- tp /c f 4 OF R.� o THE CITY OF RENTON U ���� - MUNICIPAL BUILDING 200 MILL AVE. SO. RENTON, WASH. 98055 co) "u�i CHARLES J. DELAURENTI , MAYOR • PLANNING DEPARTMENT + /Q V 235 -2550 O+ f0 S E Px��O� • June 5, 1978 Gary Crutchfield City of Tukwila Planning Division 6230 Southcenter Boulevard Tukwila, Washington 98188 Dear Mr. Crutchfield: ECEIVE JUN 6 1978 CITY OF TUKWILA Pursuant to your request for comments from this office regarding the draft E.I.S. of a proposed Park Place develop- ment, the Planning Department recognizes no substantial impact upon present or future land uses concerning nearby parcels within the corporate limits of the City of Renton. We appreciate the opportunity to review and comment on those developments within your jurisdiction that are near the City of Renton. If we can be of any further assistance, please advise. Very truly yours, Gordon Y. Ericksen Planning Director ,,gt.,..10/1444.44.4-e"-■ Steve Munson Assistant Planner GYE:SM:lml 2jmETRD Municipality of Metropolitan Seattle Exchange Bldg. • 821 Second Ave., Seattle, Washington 98104 May 26, 1978 Mr. Gary Crutchfield Planning Division City of Tukwila 6230 Southcenter Boulevard Tukwila, Washington 98188 Dear Mr. Crutchfield: flECEIVE MAY 3 0 1978 q1Y OF TUI(NryLq Draft Environmental Impact Statement Park Place Rezone Metro staff has reviewed this document, and.we do not anti- cipate adverse impacts to our wastewater facilities or public transportation system as a result of this rezone. Metro is now working with local jurisdictions to implement the recommendations of the 208 Areawide Water Quality Plan and evaluating the implementation of policy recommendations included in Environmental Management for the Metropolitan Area. While we .believe the Draft EIS did a commendable job, in discussing the water quality issues, it would be helpful if the following items were clarified. The Draft EIS makes reference to mitigating measures which could be implemented. It is difficult for us to understand the magnitude of the project's impacts unless it is made- clear which measures will actually be undertaken. Roof and parking lot detention facilities are discussed in the summary on page 15 of the Draft EIS but are not discussed elsewhere in the document. The Final EIS should specify the commitment to detention facilities and state who will be responsible for ongoing maintenance of the drainage facilities. Page 48 indicates that stormwater detention facilities will be provided in the southern portion of the site. It would be helpful if the Final EIS specified the type of detention facilities to be used - -pond, underground pipe, or rooftop. Page 49 states that attempts will be made to facilitate absorp- tion of the stormwater into the ground. This would reduce surface runoff and have beneficial effects on surface water Mr. Gary Crutchfield May 26, 1978 Page Two quality and quantity. Care should be taken so that excessive quantities of water are not introduced into the ground in steep slope areas since concentrations of groundwater in certain situations can induce landslides and extensive erosion, thereby impacting stormwater quality. Since peak flows will be detained on site, according to a statement on page 70, they should be controlled to the level which existed before construction in order to preserve water quality. The sentence on page 48 appears to be inconsistent with this, in that it states that peak flows in that area will increase by 20 to 30 percent. Thank you for this opportunity to review and comment on this document. Very truly yours, ef'4 Peter S. Machno, Manager Environmental Planning Division PSM:ksa CITY of Ti WILA • PARKS Fr RECREATION DEPARTMENT 6230 Southcenter Blvd., 7Wkwile. Wash. Telephone: 242 -2177 6230 Southcenter Blvd., Tukwila, Wash. 98188 Telephone: 242 -2177 25 May 1978 M E M O R A N D U M TO: Gary Crutchfield, Planning Division FROM: Don Williams, Recreation Division,�'(/ SUBJECT: Park Place Development Concerns This morning I met with Robert Thorpe from Robert W. Thorpe & Associates, to discuss some of my questions and concerns about the Park Place E.I.S. We reviewed all of the items I had listed in my memo to you dated 1 May 1978. I better understand their plans and generally agree with'their plan to include recreation facilities, i.e., recreation building, 1 or 2 play areas for kids under 6 years old, trails and wooded areas. My main concern is that the existing foot trail along 52nd Avenue South be preserved. .I would recommend that a condition be added to the other requirements the City may demand. That condition would be: "The developer must reconstruct the: existing 62nd Avenue South trail to a condition equal to or better than the present trail. Further that as little of the existino trail be disturbed as possible and that during project con- struction a usable and safe trail be provided at all times. In addition, the developer /architect shall work with city staff to design new trail sections that will be acceptable to,the City." •If you have any questions please give me a call. Please keep me informed. DW /ch CITY of TUKWILA OFFICE of COMMUNITY DEVELOPMENT 23 May 1978 Mr. Robert W. Thorpe R. W. Thorpe and Associates 815 Seattle Tower Third and University Seattle, Washington 98101. RE: Comments, Park Place DEIS Dear Mr. Thorpe: Please find enclosed a copy of all written comments received to date in response to the Draft EIS distributed for the Park Place proposal in Tukwila. Inasmuch as the public hearing before the Planning Commission will be conducted on 25 May 1978, it is suggested that your response document (as outlined in WAC 197 -10 -580 (2)) to the enclosed comments as well as any comments received at the upcoming public hearing be prepared subse- quent to the Commission's hearing. When completed to the satisfaction of this office, the response document will be circulated as the Final EIS in accordance with WAC 197 -10 -600. Should you have any questions or desire to discuss the responses, please call. Sincer Ga y Crut hfield Assistan Planner GC /ch Enclosures: 1) Telephone message, 2) Letter, 4/27, EPA 3) Memo, 5/1, Tukwila 4) Memo, 5/8, Tukwila 5) Letter, 5/12, DOE 4/20, Tukwila Fire Department Recreation Department Public Works Department 6230 Southcenter Boulevard a Tukwila, Washington 98188 a' (206) 242 -2177 ■ TO _ / L ( DATE A- FROM OF TIME a'D-(1 TELEPHONE NO. OR OPERATOR EXTENSION Telephoned J Please Call Back ❑ Will Call Again Wants To See You ❑ See Oper.fl MESSAGE - (s-t SIGNED CASCADE.° L1 -C2338 /44_ fez, REPLY TO ATTN 'OF: M/S 623 AP 'R 2 7 1978 REGION X 1200 SIXTH AVENUE SEATTLE, WASHINGTON 98101 Mr. Gary Crutchfield City of Tukwila Planning Division 6230 Southcenter Boulevard Tukwila, Washington 98188 Dear Mr. Crutchfield: CF, APR 281978 CITY a TUKWI A We have completed our review of your draft environmental impact statement for the Park Place Rezone in Tukwila, Washington. We would like to submit the following comments for your consideration. The draft statement's discussion of the project's impact upon air quality and surface and ground water quality is adequate, however we feel the discussion of the project's noise impact should be expanded. The draft EIS mentions, on page 15, that "heavily insulated buildings, double -pane windows, landscaping, fences, and earth berms" will be used to attenuate traffic noise, however the EIS presents no "as measured" noise levels at the project site. Building designers must know the existing exterior noise environment before they can design structures which will provide a livable interior noise level, there- fore we suggest that actual noise levels be measured and presented in the final EIS. The actual noise levels should be measured during hours of peak traffic. The final EIS should include a discussion defining those measures which will be implemented to reduce construction noise. The following list of construction noise abatement measures is suggested: 1. the use and maintenance of properly operating mufflers and quieting devices 2." the use of quietest available machinery and equipment 3. the use of electric equipment in preference to gas, diesel or pneumatic machinery ,:. •:::. z .....,.�- 2 4. locating construction equipment as far from nearby noise sensitive properties as possible 5. shutting off idling equipment 6. limitation of construction hours to coincide with the normal workday period, e.g. 8:00 a.m. to 6:00 p.m. 7. scheduling the noisiest operations near the middle of the day, and notifying nearby residents whenever extremely noisy work will be occurring 8. the use of permanent or portable barriers around point noise sources. We appreciate the opportunity to review this draft environmental impact statement. Please do not hesitate to contact Dennis Ossenkop, of my staff, should you have questions or desire further information regarding our comments. He can be reached at (206) 442 -1595. Sincerely, lft•luhLC .( et cvuLth, .. Alexandra B. Smith, Chief Environmental Evaluation Branch • • CITY of TUKWILA PARKS a REVREATOOM DEP AnTmERr 6230 Southcenter Blvd., Tukwila, Wash. 98188 Telephone: 242 -2177 1 May 1978 M E M O R A N D U M TO: Gary Crutchfield FROM: Don Williams 1/ SUBJECT: Comment on Park. Place Development After a review of the Park Place Rezone E.I.S. I have some concerns and have listed such below. You will note that my main concern is with regards to the foottrail that exists along the 62nd Avenue South Right -of -way. Some of my questions are minor and I believe some are of major concern. I assume you will present my concerns at the proper time, if not please advise me on what I can do. 1. The map on page 24 indicates a partial road connecting onto South 151st Street and to 62nd Avenue. Does this eliminate the north and south ends of the existing trail? 2. Same map on. page 24 shows several arrows indicating trails in the project connecting into our trail. The statement on page 25, 6th line down states, "Existing trails in the area are linked through the site ". Does this mean they plan to directly connect into our trail? 3. With all of the regrading, etc., that they plan to do will the changes in elevations that they make cause problems with the stability of our right -of -way and the trail? Will differences . in existing trail elevations and the new trails create a physical barrier to most users? 4. The existing trail has a 16' long bridge that allows hill drainage to continue its natural path, that is running east under the bridge and then south. Will any grading cause a change in the flow loca- tion of the current drainage basin? If so, will the bridge need to be relocated and at whose cost? Gary Crutchfield Memorandum Page 2 1 May 1978 5. If any damage is done to the path during construction who will pay for repairs? If any of the trail is eliminated because of the project will the City be compensated? 6. Will construction over the three year period be done in such a manner that the path will not be safe or easy to walk (flooding with construction drain- age, cuts made by site grading, etc.)? 7. Will the path and school palyfield be screened off with existing or a new vegetation? 8. On page 69 recreation facilities are mentioned, but mostly for adults. What provisions are being made for preschoolers and for elementary chil- dren with regards to play areas and equipment? 9. There is nothing for "sure ", but the Recreation Division is looking into the leasing of Southgate School. This may have some impact on the availa- bility of the school should elementary enrollment at Tukwila School grow beyond its capacity. However, such growth and accompaning problems could be worked out. Population growth, especially younger ages, is looked upon in a positive fashion by the Recreation Division. 10 With an increase in the population on the west side of 65th a crosswalk caution light or signal light. may be needed on 65th Avenue South at Tukwila Park. These are some of the concerns that I have. I know some of the answers have been stated in the E.I.S., but feel the answers are important enough to more fully explained. DW /ch cc: Krell Stoknes �' � � Date: May 8, 1978 To: Terry From: Dick Subject: Park Place Rezone - Preliminary DEIS MEMORANDUM C .a I have the following comment to offer: Traffic & Transportation, page 14 :. EL The mitigating measures outlined in this section do not address the additional impacts to the property east of this site. The roadway Lsystem as proposed does not allow for any through movement of traffic from So. 151st to So. 153rd and eliminates the possibility of So. 152nd Street connecting to 62nd Ave. So. The approval of the access plan as indicated would impact the property west of this site in such a way that all developments on the west 1 property will forever be restricted to using So. 152nd down to Macadam i? Road. Emergency vehicles and maintenance vehicles, rather than having r two open usable routes to any area on this hill, will be restricted to c4 one usable access point. In conclusion, I think that streets should be developed to allow for 11 free - flowing access and egress to any area on the hill from at least two difference and publicly - owned roads. These road sections should !; include all required utilities. RKW /dp r 1 L A 1'1 4 y Rj cc: Kjell Stoknes Gary. Crutchfield „Jr :71:":'''ii 1 STATE OF WASHINGTON i)ixy Lee Ray governor • DEPARTMENT OF ECOLOGY Olympia, Washington 98504 206/753 -2&X) May 12, 1978 Mr. Gary Crutchfield City of Tukwila Planning Division 6230 Southcenter Boulevard Tukwila, WA 98188 Dear Mr. Crutchfield: Thank you for the opportunity to review the Draft Environmental Impact Statement for Park Place Rezone. We have no substantive comments to offer on this project. If I can be of further service, please call me at 753 -6892. Sincerely, /;r r -c4 - CLF:bjw Carol L. Fleskes Environmental Review Section 3 MTV of TUKW LA OFFICE of COMMUNITY DEVELOPMENT 17 May 1978 M E M O R A N D U M TO: Kjell Stoknes, Di tor, OCD FROM: Gary Crutchfiel• ! stant Planner SUBJECT: THRESHOLD DETERMINATION: Ehmke -Kato Rezone & Development Checklist and additional information review by all affected departments has been completed. The following conclusions are made this office. 1. Assignment of the R -4 zone will greatly increase the density and intensity of multiple- family development currently assigned to the site. 2. Significant excavation /filling activities are included;. resulting erosion could be a problem. 3. Fire Department is concerned about inadequacy of water supply for proposed development. 4. Will significantly increase the existing traffic volume and peak loads on 62nd Avenue South. RECOMMENDATION: Based on departmental comments regarding the Environmental Checklist and the specific conclusions enumerated above, the Planning Division recom- mends an Affirmative Threshold determination be made and an Environmental Impact Statement (EIS) be prepared for use in the decision- making process. GC /ch 6230 Southcenter Boulevard m Tukwila, Washington 98188 ea (206) 242 -2177 STATE OF WASHINGTON Dixy Lee Ray Governor DEPARTMENT OF ECOLOGY Olympia, Washington 98504 206/753.2800 May 12, 1978 Mr. Gary Crutchfield City of Tukwila Planning Division 6230 Southcenter Boulevard Tukwila, WA 98188 Dear Mr. Crutchfield: Thank you for the opportunity to review the Draft Environmental Impact Statement for Park Place Rezone. We have no substantive comments to offer on this project. If I can be of further service, please call me at 753 -6892. Sincerely, er.4A-5-e— AD. CLF:bjw Carol L. Fleskes Environmental Review Section -atop crsfa C 'al 3 2. , 8 2177 Date: May 8, 1978 To: Terry From: Dick ' M E M O R A N D U M Subject: Park Place Rezone - Preliminary DEIS r . I have the follo:ving comment to offer: Traffic & Transportation, page 14: 4 t The mitigating measures outlined in this section do not address the • additional impacts to the property east of this site. The roadway Ill system as proposed does not allow for any through movement of traffic from So. 151st to So. 153rd and eliminates the possibility of So. 152nd Street connecting to 62nd Ave. So. I'? LI The approval of the access plan as indicated would impact the property •. west of•this site in such a way that all developments on the west a property will forever be restricted to using So. 152nd down to Macadam Road. Emergency vehicles and maintenance vehicles, rather than having is two open usable routes to any area on this hill, will be restricted to one usable access point. In conclusion, I think that streets should be developed to allow for 11 free- flowing access and egress to any area on the hill from at least i- two difference and publicly -owned roads. These road sections should include all required utilities. El RKW /dp cc: Kjell Stoknes • Gary Crutchfield fFJ rr. El VI Z • ►wil ~1 • CITY of TUKWILA PARKS it RECREATION DEPARTMENT 6230 Southcenter Blvd., Tukwila, Wash. f Telephone: 242 -2177 6230 Southcenter Blvd., Tukwila, Wash. 98188 Telephone: 242 -2177 1 May 1978 M E M O R A N D U M TO: Gary Crutchfield FROM: Don Williams .29-1/V SUBJECT: Comment on Park Place Development After a review of the Park Place Rezone E.I.S. I have some concerns and have listed such below. You will note that my main concern is with regards to the foottrail that exists along the 62nd Avenue South Right -of -way. Some of my questions are minor and I believe some are''bf major concern. I assume you will present my concerns at the proper time, if not please advise me on what I can do. 1. The map on page 24 indicates a parti.al"road connecting onto South 151st Street and3to 62nd Avenue. Does this eliminate the north and south ends of the existing trail? 2. Same map on page 24 shows several arrows indicating trails in the project connecting into our trail. The statement on page 25, 6th line down states, "Existing trails in the area are linked through the site ". Does this mean they plan to directly connect into our trail? 3. With all of the regrading, etc., that they plan to do will the changes in elevations that they make cause problems with the stability of our right -of -way and the trail? Will differences in existing trail elevations and the new trails create a physical barrier to most users? 4. The existing trail has a 16' ;l:ong' bridge that allows hill drainage to continue its natural path, that is running east under the bridge and then south. Will any grading cause a change in the flow loca- tion of the current drainage basin? If so, will the bridge need to be relocated and at whose cost? Gary Crutchfield Memorandum Page 2 1 May 1978 5. If any damage is done to the path during construction who will pay for repairs? If any of the trail is eliminated because of the project will the City be compensated? 6. Will construction over the three year period be done in such a manner that the path will not be safe or easy to walk (flooding with construction drain- age, cuts made by site grading, etc.)? 7. Will the path and school palyfield be screened off with existing or a new vegetation? 8. On page 69 recreation facilities are mentioned, but mostly for adults. What provisions are being made for preschoolers and for elementary chil- dren with regards to play areas and equipment? 9. There is nothing for "sure ", but the Recreation Division is looking into the leasing of Southgate School. This may have some impact on the availa- bility of the school should elementary enrollment at Tukwila School grow beyond its capacity. However, such growth and accompaning problems could be worked out. Population growth, especially younger ages, is looked upon in a positive fashion by the Recreation Division. 10. With an increase in the population on the west side of 65th a crosswalk caution light or signal light may be needed on 65th Avenue South at Tukwila Park. These are some of the concerns that I have. I know some of the answers have been stated in the E.I.S., but feel the answers are important enough to more fully explained. DW /ch cc: Kjell Stoknes CITY OF TUKWILA PLANNING DIVISION PLANNING COMMISSION STAFF REPORT 27 April 1978 8:00 P.M. AGENDA ITEM VI I C• PUBLIC HEARING: REZONE, R -1 and R -3 to R -1 through R -4 (Park Place) Application for rezone of Tracts 8, 9 and 10 of Interurban Addition to Seattle (commonly referred to as the Boeing Engineer's property) to facilitate develop- ment of 189 condominium units and 10 single - family homes on the 15 -acre parcel. A Draft EIS has been distributed as of 17 April 1978; a copy is attached for detailed review. Inasmuch as the DEIS was distributed only recently, Staff recommends the Com- mission open the public hearing on this application, receive a presentation from the proponent as well as any other pertinent comments and recess the hearing to the regular May meeting. This will allow adequate . time for Staff to prepare a sufficient Staff Report as well as, incorporate any comments regarding the DEIS. REPLY TO ATTN OF: U.S. ENVIRONMENTAL PROTECTION AGENCY M/S 623 OR 27 1978 REGION X 1200 SIXTH AVENUE SEATTLE, WASHINGTON 98101 Mr. Gary Crutchfield City of Tukwila Planning Division 6230 Southcenter Boulevard Tukwila, Washington 98188 Dear Mr. Crutchfield: ECEIVE APR 2 81978 C11Y OF TUKWILA We have completed our review of your draft environmental impact statement for the Park Place Rezone in Tukwila, Washington. We would like to submit the following comments for your consideration. The draft statement's discussion of the project's impact upon air quality and surface and ground water quality is adequate, however we feel the discussion of the project's noise impact should be expanded. The draft EIS mentions, on page 15, that "heavily insulated buildings, double -pane windows, landscaping, fences, and earth berms" will be used to attenuate traffic noise, however the EIS presents no "as measured" noise levels at the project site. Building designers must know the existing exterior noise environment before they can design structures which will provide a livable interior noise level, there- fore we suggest that actual noise levels be measured and presented in the final EIS. The actual noise levels should be measured during hours of peak traffic. The final EIS should include a discussion defining those measures which will be implemented to reduce construction noise. The following list of construction noise abatement measures is suggested: 1. the use and maintenance of properly operating mufflers and quieting devices 2. the use of quietest available machinery and equipment 3. the use of electric equipment in preference to gas, diesel or pneumatic machinery 2 4. locating construction equipment as far from nearby noise sensitive properties as possible 5. shutting off idling equipment 6. limitation of construction hours to coincide with the normal workday period, e.g. 8:00 a.m. to 6:00 p :m. 7. scheduling the noisiest operations near the middle of the day, and notifying nearby residents whenever extremely noisy work will be occurring 8. the use of permanent or portable barriers around point noise sources. We appreciate the opportunity to review this draft environmental impact statement. Please do not hesitate to contact Dennis Ossenkop, of my staff, should you have questions or desire further information regarding our comments. He can be reached at (206) 442 -1595. Sincerely, Att-4 r-vt,j1t, Alexandra B. Smith, Chief Environmental Evaluation Branch 8t(8O8 Qoc'i rm ■ it 'C DATE off/ , TIME c2`OZ) tr4JT WHILE YOU W FROM M OF Telephoned ❑ Please CaII Back MESSAGE C.;; SIGNED Will CaII Again TELEPHONE NO. OR OPERATOR EXTENSION Wants To See You ❑ See Oper.O 0,AL -A.At-+ -yu)A-) • CASCADES L1 -C2338 VRSNT[U,N U.S.A. 17 April 1978 M E M O R A N D U M TO: Recipients of Draft Environmental Impact Statement FROM: Planning Division, OCD SUBJECT: Comment Deadline on Draft EIS Please find enclosed a copy of the draft environmental impact statement for the proposed Park Place development. The pro- posed action includes rezone and development of 189 condominium units, in a PUD fashion, on 15 acres of land currently zoned for single - family residences. The Tukwila Planning Commission will conduct a public hearing at 8:00 p.m. Thursday, 27 April 1978 at 14475 —59th Avenue South in Tukwila. Comments regarding the proposal are hereby solicited. Issue date of the DEIS is 17 April 1978. Pursuant to SEPA guidelines, the comment period is 35 days, ending 22 May 1978. Please forward to this office any comments concerning the DEIS before 22 May 1978. Please address comments to: Gary Crutchfield City of Tukwila Planning Division 6230 Southcenter Boulevard Tukwila, Washington 98188 GC /ch Enclosure 101 13 MI) Robert W. Thorpe -Tn.. 47 6,er ClekfrIel- Su3./ec_7 —.• �y dIZC T,c..c..OuJ cu_! k `5 5« ti6.* ATTZ Gt cc_N.c7 w-c-c-• Zo�aC. .tcm ec`�Ss CA 2 ti "rc.o .J 1,,�..�cL p �l�du atr /JpQ6�.s° �� F -ro -mac -�- la v...1 c-› 2.6- �-�'ct t vJp Le-re. OM"( 1 a L. 'A Vine. 1,-4,r, \--40 a.,0.►, m Coo, .1 MA—. csC– .#. tz..T- -Va04, -6 OT-W-- o CSLcrt.c..bs cam. Form PP.I57 ©The Drawing Board, Inc., Box 505, Dallas, Texas TO4IVL1 AT )E CT dr-Pa—/' DATE / ,5zp hi —Dtek.dt-27 cZo- 4-0 012_A. tL FILMOISE CUMEN1,17 SIGNED /7( "f II DATE Redifirm 4S 469 Poly Pak 150 sets) 4P469 SIGNED SEND PARTS 1 AND 3 WITH CARBON IN7ACT. PART 3 WILL BE RETURNED WITH REPLY. PUBLIC SORKB DEPARTMEla 8230 Bouthcenter Boulevard Tukwila, Washington 98087 telephone C 206 3 242 - 2177 April 13, 1978 o 2 To: Gary Crutchfield, Assistant Planner 0 J From: Terry Monaghan, Public Works Direct 5 Subject: Preliminary DEIS: Park Place Rezone m dl The Public Works Department has reviewed the preliminary draft environ- x mental impact statement for the Park Place Rezone and offer the following II comments: Q a General liC This was a cursory review subject to final review particularly W with respect to utilities, roadway, access, drainage and traffic flows and patterns. W Specific Comments ii Page 63, paragraph 5.a. - Energy W To the best of my knowledge, the Department of Public Works did not give any input to location of gas mains. We do not maintain Q the records of gas main locations and we refer all inquiries to 3 Washington Natural Gas Co. This paragraph should be amended to reflect this. il F. Page 68, paragraph 5 - Sewer W The narrative of the location of the 8" sanitary sewer states W it is on the northwest corner and Figure 13 shows it to be on a the northeast corner. The northeast corner is correct. 6 H The sewer extension referenced on 62nd Ave. So. will be extended and development dictates under an LID. Final design of this (' facility is not complete and the size may be larger than 8 ". iE Page 68, paragraph 5 - Storm Drainage Reference to specific location of storm drainage facilities on W 62nd Ave. So. for peak flows is inconsistent with earlier refer - W ence to retaining peaks on site to control runoff. The runoff Z facilities in the public right -of -way have not been designed Eiand may not use 62nd Ave. So. z Page 71, paragraph 5.b. - Storm Drainage W Reference to releasing storm drainage into an improved sanitary • sewer main along 62nd Ave. So. is contrary to existing City of Tukwila and Metro standards. These do not allow storm water into sanitary systems. e, • 2. Page 62, paragraph c. - Mitigating Measures Other options to the proposed access and egress to the site should be addressed. TRM /dp • Edgar D. Bauch City of Tukwila Mayor Fire Department April 12, 1978 Hubert H. Crawley Fire Chief Gary Crutchfield, Asst. Planner Planning Department City of Tukwila Dear Gary: Regarding the Preliminary DEIS for Park Place Rezone, after reviewing the environmental impact statement for the Park Place Rezone, we are concerned with three areas which still have not been addressed to our satisfaction: Circulation allowed the buildings will still not comply with total requirements for access to buildings. There still has been no hydraulic calculations rendered as to the fire flow available at this location. It is very doubtful that adequate water is available to protect the structures they are wanting to build. One method of solving this problem of reduced fire flow would be sprinklering of the structures. Finally, the total access to the site is inadequate for emergency equipment to respond to within a reasonable time frame. All records indicate that not only in the City of Tukwila, but throughout the nation, private fire lanes are not maintained and often are closed when needed the most. Since these structures represent high life hazard, with limited access and unfavorable topography to maneuver fire apparatus in, we still cannot approve the draft as presented in the environmental impact statement. If I can be of any help in clarifying any of the above state- ments in regard to this building, feel free to contact me at any time. I talked to Mr. Thorp, representing this project, on Tuesday, April 11 and advised him of the same conditions as discussed in this letter. HHC:vma Hubert H. Crawley cc:TFD file Fire Chief City of Tukwila Fire Department, 444 Andover Park East, Tukwila, Washington 98188 (206) 575 -4404 VII Alternatives to the Proposal The following alternatives are summarized on page 13. These alternatives are ones that are readily available under existing or proposed zoning and are modifications of the proposal developed by Northward that would satisfy the general goals and intent of their proposal. 1. #Tse of the site for single- family (R -1) and fourplex (R -3) under existing zoning. As shown in Figure 3 half of lot 10. is presently zoned R -3, which would allow for fourplexes with the balance of the property being R -1, 12,000 square foot lots. The zoning was developed at the time the city was incorporated and carried on the site in the absence of any zoning request on the property. The former comprehensive plan showed this entire area for apartments without any density clarification. Under the former compre- hensive plan properties contiguous to and west of the subject property were rezoned to R -4 and RMH. Properties to the southeast were rezoned to R -4. At present there is an application on the property to the south to change the zoning from R -3 to R -4. The revised comprehensive plan calls for a break in densities and uses over the site ranging from high density multi - family on the southwest, low density multi - family in the middle portions and -low density on the northeast corner. . Preliminary studies conducted by site planners for the. Tukwila Associates group indicated that single- family development of the site would be . possible, however, extensive costs would be associated in tertns of providing roads and access and the impacts on the site might be much more significant than that of clustered housing with open space areas provided for in steep slope areas, drainage areas and difficult soil areas. Disamenities such as noise, location near very dense, existing apartment complexes made the . decision to utilize the property for single family an unattractive one to the property owners and potential users who would develop the property. 2. Maximum utilization of the property south and west of the ridge line for R -4 zoning, R -3 along the ridge line, the balance of the site in R -2 and .open space. This alternative has been presented as part of a previous request to the Planning Commission and Council for rezone and waiver of portions of Resolution 489. Under this proposal the southwest portion of the property would be used for an R -4 apartment complex at a density of approximately 28 to 30 units per acre for 6 to 61 acres. The R -3 zoning would provide for townhouse condominiums at 16 to 20 units per acre over 6 to 61 acres. Duplex and triplex townhouses would be developed at 8 to 10 units per acre; with approximately 2 acres of the balance of the property in open space. The proposal is summarized in the table below. SUMMARY OF USES AND DENSITIES Area Housing Type Density /Acre Acres Total Units 1 Apartments /Townhouses 30 6.0 -6.5 180 - 195 2 Townhouses /Condominiums 16 - 20 6.0 -6.5 108 - 130 3 Duplex & Triplex Townhouses 8 - 10 .2.2 -3.2 16 - 32 304 - 356 It should be noted that this is a modification from previous considerations on this property by Tukwila Associates, original owners. The previous application had suggested 28 to 30 units per acre or a density approaching 450. The modified application discussed a range of 29 to 24 units per acre or 304 to 365 units. At the time of this application, the Comprehensive Plan had not been adopted and the City was acting under Resolution 489. At that time some of the densities proposed were felt to be inconsistent with the emerging comprehensive plan.. The applica- tion was denied with direction given to modify the application following the adoption of the Comprehensive Plan. 3. Utilization of existing zoning classifications on individual lots as follows: R -2. on Lot 8: R -3 on Lot 9 and R -4 on Lot 10. The splitting of these three formerly platted areas, approximately 5 acres in each lot, would provide for the application of a separate zoning request on each lot. A transition zone could be established on each property from adjacent properties to the north and south. The zoning classification would provide for duplex uses on the entire portion of Lot 8, triplexes on Lot 9 and more dense apartment units on Lot 10. The resulting densities would be r 0. to 6 units on Lot 8, 7 to 16 units on Lot 9 and 17+ units per acre on Lot 10.. Under maximum utilization this would provide for 30 units on Lot 8; 80 units on Lot 9 and 85 to 140 units on Lot 10 - -a total range of 195 to 250 units under this type of proposal. This assumes a limitation on the R -4 consistent with the comprehensive plan guidelines of 38 units per acre rather than the zoning code limitation of 43 units per acre. If R -4 under the zoning code was utilized for Lot 10, the upper range of units . under this proposal would be 325 units. 4. All uses as proposed except that the single - family area would be retained as open space either by covenant to keep as a natural area or deeded in fee to the City as passive open space area with a potential site for a water reservoir facility. This alternative has been discussed as part of the comprehensive pianninr, process and letters from the original property owners conveyed to the City indicating that this was a viable alternative to them. Subsequent conversations with various members of the City staff have indicated a strong concern at the City for providing single- family sites. A review of, the land use inventory document developed as part of the comprehensive planning process indicated that there have been only 12 single - family homes built in the area in the last 11 years up to 1976. The proposed additional 10 single - family sites would match the single- family development in Tukwila for the past 8 or 9 years. The area proposed to be open space would be an extension of that 2.6 acres of open space along the ridge line. In that this area is highly suitable for low density development, either clustered duplex townhouses or single - family the proposal to provide single- family in this area to both provide additional housing stock of a single - family nature in Tukwila and provide a well- defined transition zone from the existing R -196 to the north and northeast as ;elm as help to define : :hat would occur on the property to the east appears to be the more logical alternative. However, the alternative of leaving this area an • • open space remains a viable one and should be determined as part of4 policy decision by the Planning Commission and City Council. 5. Modify size and configuration of proposed use zones. A myriad of alternatives, whereby minor modifications of the configurations of the proposed site plan could be under taken. The proponents' architect, site planners and others involved in the project have undertaken numerous alternative discussions and analysis of feasible and viable projects. These discussions have also be clarified and directed by numerous discussions with the City staff. Minor modifications of the existing zoning proposals could be made as a part of the hearing process. However, at this time proposed action appears to be responsive to the natural system in response to the comprehensive plan map and policies an consistent with feasibility studies done for various developments on the site. 6. No action. This alternative would leave the site in its undeveloped character awaiting utilization of adjacent properties for residential uses of various densities from RMH to detached single - family under R -1. Feasibility studies have shown that other than minor portions of the site being used for single - family it is highly unlikely that the property would be developed in t he short term 'absent any re4oning action. The proponent . does not have access to alternate: sites . and given a decision not to approve this zoning application or some modification thereof, would withdraw from the project. The previous fee owners under contract purchase with the proponent would retain the property until zoning action could be clarified. With construction costs and land values escalating under inflationary pressures and a change in the present strong condominium market could.lead to additional pressures for more dense development on the subject property in the future. 10 April 1978 • CITY of TUKWILA OFFICE of COMMUNITY DEVELOPMENT M E M O R A N D U M TO: Gary FROM: Al SUBJECT: Park Place Rezone The primary interest of the Building Department on this site is the swampy condition of certain portions of the site. These conditions would normally be approached at time of building permit application. However, due to the scope of the development, I feel that the swampy conditions should be evaluated and alleviated during the rezone process. AP /ch oveArn 6230 Southcenter Boulevard • Tukwila, Washington 98188 • (206) 242 -2177 • CITY of TUKWILA OFFICE of COMMUNITY DEVELOPMENT 5 April 1978 M E M O R A N D U M TO: SEE DISTRIBUTION FROM: Gary Crutchfield sistant Planner SUBJECT: Preliminary DEIS -: Park Place Rezone Attached is a preliminary Draft Environmental Impact Statement for the proposed rezone and development of "Park Place" (commonly referred to as the Boeing En- gineers' property) at the northwest corner of the intersection of 62nd Avenue and South 153rd Street. Please review the preliminary document for substance and return with agX- comments within your respective area of expertise. Comments should be returned to me no later than noon Wednesday, 12 April 1978. If I can be of any assistance, please call. GC /ch Attachment DISTRIBUTION: Dir, P/W Fire Chief Police Chief Bldg Off 6230 Southcenter Boulevard • Tukwila, Washington 98188 • (206) 242 -2177 CITY of TUKWRLA OFFICE of COMMUNITY DEVELOPMENT 5 April 1978 MEMORANDUM TO: SEE DISTRIBUTION FROM: Gary Crutchfield istant Planner SUBJECT: Preliminary DEIS: Park Place Rezone Attached is a preliminary Draft Environmental Impact Statement for the proposed rezone and development of "Park Place" (commonly referred to as the Boeing En- gineers' property) at the northwest corner of the intersection of 62nd Avenue and South 153rd Street. Please review the preliminary document for substance . and return with L comments within your respective area of expertise. Comments should be returned to me no later than noon Wednesday, 12 April 1978. If I can be of any assistance, please call. GC /ch Attachment DISTRIBUTION: Dir, P/W Fire Chief Police Chief Bldg Off 6230 Southcenter Boulevard ® Tukwila, Washington 98188 0 (206) 242 -2177 R.W. THORPE &ASSOCIATES 815 Seattle Tower Third & University Seattle, Washington 98101 (206) 623 -2935 Mr. Fred Satterstrom Planning Supervisor Department of Community Development City of Tukwila Tukwila, Washington 98188 March 31, 1978 &CE1VE MAR 31 1978 CITY OF TUKWILA RE: Letter of Transmittal- -Items for Contract Rezone, Northward Development Co. Dear Fred: Attached herewith you will find the following that are a) required for the rezone application; b) those requested by the City; and c) those items submitted to assist in explaining the details of the overall plan and application. They include: 1. The City's application form 2. A check for $200 3. An affidavit of ownership (contract purchase) 4. 'Property ownerships within 300 feet of the property 5. Assessor's maps 6. Vicinity maps 7. Two sets of drawings: at full size and two sets of reduced maps Architecture a) Project description b) Existing conditions c) Site plan d) Grading plan (cuts & fills) e) Site sections f) Typical units (3 sheets) g) Elevations (3 sheets) Engineering a) Drainage plan b) Existing drainage c) Water system d) Sanitary sewer system Miscellaneous (small sets) a) Kroll b) Topography c) Slope analysis 8. Draft EIS (for staff review) 5 copies Note: References and some appendices items to be determined by staff /consultant discussions. I will visit your office Monday a.m. (9:00) to check that all items are in order and arrange a time to meet on the DEIS to review your co ts. Thank you. Y RWT:nab cc Northward Corporation McClarty & Johnson Triad Associates. • • R.W. THORPE & ASSOCIATES 815 Seattle Tower Third & University Seattle, Washington 98101 March 30, 1978 Tukwila Planning Department Tukwila City Hall Tukwila, Washington Attention: Fred Satterstrom and Kjell Stoknes RE: Contract Rezone Application by Northward Corporation for 14.7 Acre Site on Tukwila Hill Gentlemen: This letter, a part of the contract rezone application and "PRUD" for Northward Corporation, is conveyed to you to stipulate our agreement concerning processing of this application and review under the State Environmental Policy Act of 1977 and SEPA Guidelines. Normally an environmental checklist is filled out and a determination is made by the responsible official as to whether an environmental impact statement is necessary. However, at our request, in order to expedite this application and provide for full disclosure of informa- tion concerning it, we are filing a draft environmental impact statement containing a full review of the project and technical appendixes on identified areas of concern. We recognize that no determination of significance has been made by the City of the responsible official and may not require an EIS; however, we are requesting to exercise the option provided for the applicant in the SEPA Guidelines, Chapter 197 -10 Washington Administrative Code. We request that the EIS be reviewed as part of the rezone process that it be considered at a public hearing by the Planning Commission at the time the rezone and "PRUD" concept is considered. We recognize that this document can provide the necessary information to complement the architectural and engineering drawings and be utilized for an information tool for the decision - making process. We have written the DEIS with that intent in mind as well as full compliance with SEPA Guidelines. We trust this is in keeping with our discussion on this portion of the application. RWT:DG:nab Yours very truly, F ALsy -'iJ Robert W. Thorpe .iR. W orpe Associates A Dick Gilroy Northward Corporation