Loading...
HomeMy WebLinkAboutPermit L09-012 - SMITH / OHNO / COOKE CREEK MEADOWS - SPECIAL PERMISSION BUFFER REDUCTIONCOOKS CREEK MEADOWS SPECIAL PERMISSION BUFFER REDUCTION Todd Smith 13325 Macadam Rd S L09 -012 • • Related files with supporting documentation Oq O/ 2 RFA08 -273 Tree and Brush clearing in a wetland buffer and steep slope L08 -065 Tree Clearing Permit for RFA08 -273 RFA10 -314 Clearing and Grading outside buffer without a permit PW10 -295 Clearing and Grading Permit for RFA10 -314 PRE07 -026 Preapp for consideration into housing options program PRE08 -023 Preapp for Cottage Housing 109 -012 Buffer Reduction — Contains critical area sensitive areas info for buffer, tree, and sepa 109 -013 Design Review -- Contains Cottage Housing Review info L09 -020 Short Subdivision E09- 001 —SEPA C09 -007 Traffic Concurrency for 9 cottages and demo of one house PL13 -009 Project file L13 -008 Appeal of Revocation of L09 -013 June 1, 2010 City•of Tukwila 1 Jim Haggerton, Mayor Department of Community Development NOTICE OF DECISION TO: Todd Smith, Applicant King County Assessor, Accounting Division Washington State Department of Ecology USACOE Jack Pace, Director This letter serves as a notice of decision and is issued pursuant to TMC 18.104.170 on the following project and permit approval. I. PROJECT INFORMATION Project File Number: L09 -012 Buffer Reduction, L08 -065 Tree Clearing Permit Applicant: Todd Smith, Property Owner Type of Permit Applied for: Special Permission from the Director to deviate from the City's buffer requirements for a Type 3 wetland buffer; Tree Clearing permit (mitigation plan) for unauthorized tree clearing in a critical area sensitive area buffer. Project Description: Location: Associated Files: Comprehensive Plan Designation/Zoning District: II. DECISION SEPA Determination: SM H:\A Cooke Cottages\SAO NOD.doc The applicant has been selected by the City to develop his site into a 9 -lot compact single family development under the City's Housing Options Ordinance. As part of the site design, the applicant is seeking approval of a 50% buffer reduction, buffer mitigation and enhancement plans, wetland dredging and tree clearing permit. The applicant has requested to reduce the buffer distance from 50 feet to 25 feet. Additionally, using low - impact development techniques, some stormwater from the site will eventually be discharged into the buffer area and wetland. 13325 Macadam Road South L09 -020 (Short Plat), E09 -001 (Environmental Review), L09 -013 (Design Review), future Development Permit and future Public Works Activities Permits Low - Density Residential (LDR) A Determination of Non - Significance was issued on November 20, 2009. Page 1 of 3 06/01/2010 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone 206 -431 -3670 • Fax: 206 - 431 -3665 • Decision on Substantive Permit: The Community Development Director has determined that the application for wetland enhancement, wetland buffer reduction and tree clearing in preparation to develop a 9 -lot compact single family project complies with applicable City and state code requirements and has approved that application, subject to any conditions which are set forth in the Decision based on the findings and conclusions contained in the staff report. The following conditions have been placed on the project: 1. Work in the mitigation area will only occur during non - flowing/saturated conditions. The preferred time for construction is in the dry season (June- October). 2. Prior to the issuance of the Public Works permit: a. Provide a cost estimate of the labor and materials for the five year monitoring requirement for the City's approval. b. Submit a performance and maintenance security guarantee (bond or cash assignment) of 150% of the approved cost of labor and materials for the project to guarantee performance, maintenance, monitoring costs and correction of possible deficiencies. The guarantee may be held longer than 5 years if the performance standards have not been met or the mitigation has not been successfully established (TMC 18.45.090F7 and 18.45.210). 3. Monitoring: a. A monitoring report, prepared by a qualified wetland biologist that documents performance of the wetland/buffer area in comparison to the performance standards, shall be submitted to the City on an annual basis, starting approximately 1 year after completion of the construction. b. The monitoring report shall include evidence that this project has not changed the hydrology of any downstream, off -site wetlands. Prior to the final inspection of the public works permit the applicant shall provide baseline off -site hydrology conditions and the future monitoring shall be compared to the baseline conditions. c. A qualified landscape maintenance contractor is required to carry out the maintenance for the five year monitoring period. III. YOUR APPEAL RIGHTS The Decision on this Permit Application is a Type 2 decision pursuant to Tukwila Municipal Code § 18.104.010. Other land use applications related to this project may still be pending. No administrative appeal of a DNS or an EIS is permitted. One administrative appeal to the Planning Commission of the Decision on the Permit itself is permitted. If an MDNS was issued, any person wishing to challenge either the conditions which were imposed by the MDNS decision or the failure of the Department to impose additional conditions in the MDNS must raise such issues as part of the appeal to the Planning Commission. A party who is not satisfied with the outcome of the administrative appeal process may file an appeal in King County Superior Court from the Planning Commission decision. IV. PROCEDURES AND TIME FOR APPEALING In order to appeal the Community Development Director's decision on the Permit Application, a written notice of appeal must be filed with the Department of Community Development within 21 days of the issuance of this Decision, which is by June 23, 2010. SM H:W Cooke Cottages \SAO NOD.doc Page 2 of 3 06/01/2010 • The requirements for such appeals are set forth in Tukwila Municipal Code 18.116. All appeal materials shall be submitted to the Department of Community Development. Appeal materials MUST include: 1. The name of the appealing party. 2. The address and phone number of the appealing party; and if the appealing party is a corporation, association or other group, the address and phone number of a contact person authorized to receive notices on the appealing party's behalf. 3. A statement identifying the decision being appealed and the alleged errors in the decision, including any specific challenge to an MDNS. 4. The Notice of Appeal shall identify (a) the specific errors of fact or errors in application of the law in the decision being appealed; (b) the harm suffered or anticipated by the appellant, and (c) the relief sought. The scope of an appeal shall be limited to matters or issues raised in the Notice of Appeal. 5. Appeal fee of $115. V. APPEAL HEARINGS PROCESS Any administrative appeal regarding the Permit shall be conducted as an open record hearing before the Hearing Examiner based on the testimony and documentary evidence presented at the open record hearing. The Hearing Examiner's decision on the appeal is the City's final decision. Any party wishing to challenge the Director's decision on this application must file an appeal pursuant to the procedures and time limitations set forth in RCW 36.70C. An appeal challenging a DNS, an MDNS or an EIS may be included in such an appeal. If no appeal of the Planning Commission decision is properly filed in Superior Court within such time limit, the Decision on this permit will be final. The City's decision to issue a DNS, an MDNS or an EIS is final for this permit and any other pending permit applications for the development of the subject property. VI. INSPECTION OF INFORMATION ON THE APPLICATION Project . materials including the application, any staff reports, and other studies related to the permits are available for inspection at the Tukwila Department of Community Development, 6300 Southcenter Blvd., Suite 100, Tukwila, Washington 98188 from Monday through Friday between 8:30 a.m. and 5:00 p.m. The project planner is Stacy MacGregor, who may be contacted at 206 - 433 -7166 or smacgregor @ci.tukwila.wa.us for further information. Property owners affected by this decision may request a change in valuation for their property tax purposes. Contact the King County Assessor's Office for further information regarding property tax valuation changes. The notice board must be removed at the expiration of the appeal period if no appeal is filed. Jack ace, Director Dep ent of Community Development - City of Tukwila SM H:\A Cooke Cottages\SAO NOD.doc Page 3 of 3 06/01/2010 City of Tukwila Department of Community Development MEMORANDUM June 1, 2010 TO: Jack Pace, Director, Department of Community Development FM: Stacy MacGregor, Assistant Planner Jim Haggerton, Mayor Jack Pace. Director RE: L09 -012: Special Permission- Director, Request to Alter a Type 3 Wetland and Reduce a Type 3 Wetland Buffer; L08 -065: Request to Approve a Buffer Enhancement Plan for unauthorized tree clearing in a sensitive area Todd Smith, property owner, and Chandler Stever, project architect, have received approval to develop a cottage housing project under the Housing Options Program (TMC 18.120). The 9 -home cottage development is dependent upon a wetland buffer reduction to create the building area needed for the project's design. Following approval of a buffer reduction, a short plat application and design review decision will be pursued. Sensitive area enhancement is also required as mitigation for unauthorized tree clearing within the wetland and stream buffers. The project site contains a Type 3 wetland with associated buffers and the buffer for a Type II stream. The applicant has requested to reduce the development (east) side of the wetland buffer from 50 feet to 25 feet plus the required 10 foot building setback. Located within the reduced buffer would be portions of two cottages, landscaping and pathways, a portion of a rain garden and a 50' dispersion trench. The project proposes to use both sides of the wetland and the stream buffer for sensitive area enhancement and mitigation. The buffered area between the wetland and stream will be improved to enhance their function via native plantings and removal of invasive species; a walking trail . will lead through the buffers; the wetland volume will be increased through excavation to increase the holding capacity of the wetland and planted to improve the wetland's water filtration. Some of the stormwater from the site will filter through the rain garden system and be dispersed into the wetland. A weir will be installed that will hold back the increased water volume and act as a footbridge over the wetland. The applicant has applied for a permit from the USACOE for work within the wetland. This application is seeking approval of a 50% buffer reduction, buffer mitigation and enhancement plans, wetland dredging and tree clearing permit. Background The project site contains a Type 3 wetland and is adjacent to Southgate Creek, a Type II stream. TMC 18.45.080 defines Type 3 wetlands as wetlands that are greater than 1,000 square feet and less than one acre in size with two or fewer wetland classes; Type 3 wetlands require a 50 -foot buffer. TMC 18.45.100 defines a Type II stream as a stream that has perennial or intermittent flow and supports salmonid fish. A Type II stream is required to have a 100 -foot buffer from ordinary high water mark (TMC 18.45.100). The site contains two parcels with one house on the eastern-most parcel. In the past, the area between the wetland and the stream was used as a garden area for the existing home. According to the applicant, water in the wetland has decreased in recent years and this decrease occurred simultaneously with upland development. It appears that in the past, the site was cleared and according to the applicant's Geotechnical Report fill was brought onto the site. The wetland is bisected by a drainage swale. SM H:\A Cooke Cottages \SAO SR.doc Page 1 of 7 06/01/2010 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone 206 -431 -3670 • Fax: 206 -431 -3665 • According to the Conceptual Mitigation Plan dated October 16, 2007, the habitat functions of the wetland and buffer are limited and the water quality functions and hydrologic functions are moderate. The buffer contains invasive non - native vegetation including reed canary grass, blackberries and ivy. Decision Criteria Tukwila Municipal Code (TMC) 18.45 addresses Environmentally Sensitive Areas. The applicable portions of this code are referenced below along with staff's response describing how the proposal meets the code. TMC 18.45.070 SENSITIVE AREA PERMITTED USE The following uses may be located within a sensitive area or buffer: A3) Passive recreation and open space. A path is proposed within the watercourse and wetland buffer. It will be made of play chips over 2 layers of biodegradable cardboard or burlap. B5) Enhancement or other mitigation including landscaping with native plants subject to administrative review. The wetland and all buffers will be landscaped with native plants and the invasive non - native species will be removed. TMC 18.45.070B.9 Dredging, Digging or Filling a) Dredging, digging or filling within a sensitive area or its buffer may occur only with the permission of the Director and only for the following purposes: 1) Uses permitted by TMC 18.45.080, 18.45.090, 18.45,110, 18.45.130; According to TMC 18.45.080 (3), wetland functions include, but are not limited to the following: a) Improve water quality; b) Maintaining hydrologic functions (reducing peak flows, decreasing erosion, groundwater); and c) Providing habitat for plants, mammals, fish, birds, and amphibians. The proposed dredging is part of a low- impact development technique that will filter some of the roof drains from the nine homes through a rain garden system and into the wetland. The goal of dredging is to increase the holding capacity of the wetland needed due to the increased discharge from development. The landscaping, removal of invasive species, and improved soil proposed in the plan is intended to improve the functioning of the wetland, increase hydrology on site and holding capacity during 100 -year flood events, and improve water quality on and off site. From the SEPA Staff Report (E09 -001): "50% of the driveway stormwater will be tight -lined into the storm drain system. All of the remaining stormwater on the site will be filtered through the rain gardens before either entering the storm drain system, the wetland, or used on site for irrigation. Three of the houses (1, 2 & 3) will have about 30% of the stormwater flow through a rain garden system to the east then tight -lined into the existing stormwater conveyance system. The remaining 70% stormwater runoff from the site flows into the wetland via the dispersion trench. The run -off from six houses (4, 5, 6, 7, 8 & 9) will be directed through the rain gardens and used to hydrate the common landscaping. Excess water will be dispersed into the wetland from a 50' dispersion trench running north -south 25' from the wetland. The impervious concrete driveway will divert 50% of the stormwater east tight -lined to the stormwater drain system. The remaining 50% will flow west connecting to the rain garden system getting filtered and biologically treated before it enters the wetland." 2) Maintenance of an existing watercourse; This does not apply as a watercourse does not occur on the property. 3) Enhancement or restoration of habitat in conformance with an approved mitigation plan identified in a sensitive area study; This proposal includes a mitigation plan designed to provide wildlife habitat. The plan includes native plantings and non- native plant removal. The design adds a native grass meadow to attract raptors and the addition of snags, stumps, and logs to provide habitat for wildlife. SM H:\A Cooke Cottages\SAO SR.doc Page 2 of 7 06/01/2010 4) Natural system interpretation, education or research when undertaken by, or in cooperation with the City; This does not apply as the project is private and not proposed by the City. 5) Flood control or water quality enhancement by the City; This does not apply as the project is private and not proposed by the City. 6) Maintenance of existing water quality controls, for normal maintenance needs and for any diversion, rerouting, piping or other alteration permitted by TMC Chapter 18.45; The goal of dredging is to increase the holding capacity of the wetland. The holding capacity is to be increased as an alternative to routing surface water into the stormwater system. 7) Filling of abandoned mines. This does not apply as the project does not propose filling an abandoned mine. b) Any dredging, digging or filling shall be performed in a manner that will minimize sedimentation in the water. Every effort will be made to perform such work at the time of year that the impact can be lessened According to Sheet W -1, 2.6 of the mitigation plan, "All graded areas will be stabilized with hydroseed or mulch per 3.4.2 upon completion of grading. Orange construction fencing and /or erosion control fences will be placed around the mitigation area. Flow of water through the mitigation area will not commence until all bare soil surrounding the channel has an established grass layer. The preferred time for construction is in the dry season (June- October). Work in the mitigation area will only occur during non - flowing/saturated conditions. c) Upon completion of construction, the area affected must be restored to an appropriate grade, replanted according to a plan approved by the Director, and provided with care until newly planted vegetation is established According to Sheet W -1, 4.0 of the mitigation plan, "...a maintenance contract shall be established with a qualified landscape maintenance contractor to carry out maintenance for the 5 year period after planting, as a condition of the final PW grading permit approval." TMC 18.45.080 WETLAND DESIGNATIONS, RATINGS AND BUFFERS TMC 18.45.080.G permits the Director to reduce a wetland buffer width based upon the following criteria: 1) The reduced buffer area does not contain slopes over 15% and is not over 50 %; This project does not contain slopes over 15 %. The applicant is requesting to reduce the buffer from 50 feet to 25 feet, thus the buffer reduction is 50 percent of the required buffer. 2) a) Additional protection to wetlands will be provided through the implementation of a buffer enhancement plan; A buffer enhancement plan is included in this request. b) The existing condition of the buffer is degraded; The buffer is degraded with invasive species infiltration. Additionally, the applicant removed 6 trees within the wetland and stream buffers. According to the Conceptual Mitigation Report, dated October 16, 2007, "the habitat functions of Wetland A (on the applicant's property) and its buffer are limited by the prevalence of non - native invasive species, mainly Himalayan blackberry and reed canary grass. English ivy is also present in some areas of the wetland and buffer. Water quality functions are moderate due to the presence of dense vegetation and lack of a surface water outlet." c) Buffer enhancement includes, but is not limited to the following: 1) Planting vegetation that would increase value for fish and wildlife habitat or improve water quality; Native plant species will aid in the Mitigation Concept (Sheet W -1, 1.1). The wetland creation area will provide greater floodway attenuation and ecological benefits while being aesthetically pleasing. SM H:\A Cooke Cottages \SAO SR.doc Page 3 of 7 06/01/2010 2) Enhancement of wildlife habitat by incorporating structures that are likely to be used by wildlife, including wood duck boxes, bat boxes, snags, root wads /stumps, bid houses and heron nesting areas; or Sheet WT -1, Legend states that the project shall include at least 2 snags, 3 logs, and 3 stumps. 3) Removing non - native plant species and noxious weeds from the buffer area and replanting the area subject to TMC 18.45.080G.2.c(1) Sheet W -1, 3.1.3 states that "the landscape contractor will hand grub all invasive species. Weed debris will be disposed of off site." 4) Every reasonable effort shall be made to maintain the existing viable native plant life in the buffers. •Vegetation may be removed from the buffer as part of an enhancement plan approved by the Director. Enhancements will ensure that slope stability and wetland quality will be maintained or improved. Any disturbance of the buffers for wetlands shall be replanted with a diverse plant community of native northwest species that are appropriate for the specific site as determined by the Director. If the vegetation must be removed, or because of the alterations of the landscape the vegetation becomes damaged or dies, than the applicant for a permit must replace existing vegetation along wetlands with comparable specimens, approved by the Director, which will restore buffer functions within five years; and The proposal includes a contingency plan that addresses this requirement. The site is predominately invasive non - natives. The few native trees on the site will remain. The proposed site plan has been developed and reviewed in coordination with the applicant's engineer, landscape architect, and wetland biologist. Additionally, City staff including the Urban Environmentalist has reviewed the plan. The planting palette consists of native species appropriate for the site conditions. Sheet W -1, 5.2 lists Standards of Success which include the following: 1. Evaluation of the success of the mitigation project will be based upon 100% survival for all planted woody vegetation at the end of year 1 and 80% survival for all planted woody vegetation at the end of year 5. 2. Not more than 10% cover of non - native invasive species within the mitigation area at the end of any year during the 5 year monitoring period. 3. Saturation within the creation area during the early growing season that meets US Army Corps hydrology criteria. - 4. Volunteer native, non - invasive species will be included as acceptable components of the mitigation, but will not be counted towards the 80% success requirement. Sheet W -1, 5.4 states that "if the monitoring results indicate that any of the performance standards are not being met, it may be necessary to implement all or part of the contingency plan.... Contingency /maintenance activities will include, but are not limited to: Replacing all plants lost to vandalism, drought, or disease, as necessary. Replacing any plant species with a 20 percent or greater mortality rate with the same species or similar species approved by the City. 5) The Director shall require subsequent corrective actions and long -term monitoring of the project if adverse impacts to regulated wetlands or their buffers are identified. In addition to the Standards of Success and Contingency Plan included in the proposal, the applicant shall provide a bond or cash assignment in the amount of 150% of the value of the labor and materials for the project to guarantee performance, maintenance, monitoring costs and correction of possible deficiencies. The guarantee may be held longer than 5 years, if the performance standards have not been met or the mitigation has not been successful. TMC 18.45.090 WETLAND USES, ALTERATIONS AND MITIGATION 18.453.090.B permits the alteration of a Type 3 wetland with the permission of the Director. The alteration is subject to a mitigation or enhancement plan in addition to the following: -- ... 1) a) The alteration will not adversely affect water quality; The project is designed to improve filtration of stormwater entering and exiting the wetland which should improve water quality. SM H:\A Cooke Cottages\SAO SR.doc Page 4 of 7 06/01/2010 b) The alteration will not adversely affect fish, wildlife, or their habitat; The project is designed to improve the area with native vegetation which should improve habitat. c) The alteration will not have an adverse effect on drainage and/or stormwater detention capabilities; The alteration is designed to support a 100 -year flood event while maintaining drainage rates downstream of the wetland. Monitoring will verify that there are no adverse effects on drainage or stormwater detention capabilities. d) The alteration will not lead to unstable earth conditions or create an erosion hazard or contribute to scouring actions; The project is to comply with Geotechnical Engineering Report, by GEO Group Northwest, dated July 17, 2008. ESC measures as recommended in the 1998 KCSWM must be utilized. e) The alteration will not be materially detrimental to any other property; and A monitoring program is required as a condition of this project. A detailed monitoring program must be completed prior to the final Public Works grading permit. The monitoring report will address off -site impacts. If detrimental impacts occur on any other property as a result of this project, they shall be mitigated by the applicant. j) The alteration will not have adverse effects on any other sensitive areas. A monitoring program is required as a condition of this project. A detailed monitoring program must be completed prior to the final Public Works grading permit. The monitoring report will consider impacts to any other sensitive areas. If adverse effects occur to any other sensitive area as a result of this project, they shall be mitigated by the applicant. g) Isolated Type 3 wetlands may be altered or relocated only with the permission of the Director. A mitigation or enhancement plan must be developed and must comply with the standards or mitigation required in TMC Chapter 18.45. Mitigation plans that comply with the standards of TMC 18.45 are included in this application. h) Mitigation plans shall be completed for any proposal for dredging, filing, alteration and relocation of wetland habitat allowed in TMC Chapter 18.45. Mitigation plans are included in this application. MITIGATION PLANS TMC 18.45.070 -090 and 18.54.080.4 require sensitive areas enhancement or mitigation plan for digging in the wetland, . the buffer reduction, wetland alteration, and clearing in a sensitive area or buffer. 1) The mitigation plan shall be developed as part of a sensitive area study by a specialist approved by the director. Wetland and/or buffer alteration or relocation may be allowed only when a mitigation plan clearly demonstrates that the changes would be an improvement of wetland and buffer quantitative and qualitative functions. The plan shall follow the performance standards of TMC Chapter 18.45 and show how water quality, wildlife and fish habitat, and general wetland quality would be improved. The submitted mitigation plan has been prepared in concert with a landscape architect, an engineer, and a wetlands ecologist. The proposed plan improves the wetland and buffer function and meets the performance standards of TMC Chapter 18.45. According to TMC 18.45.090 F, a mitigation plan requires the following components: a) Baseline information of quantitative data collection or a review and synthesis of existing data for both the project impact zone and the proposed mitigation site; The wetland capacity and drainage specifications were addressed based on flow control. In a developed condition, the increase peak flow to the wetland is .096cfs. The wetland volume increase was engineered to create no change in down stream flows and to provide storage capacity during a 100 -year flood event. The weir is designed to be adjusted in response to annual monitoring if site conditions indicate flow rate changes. The applicant will provide offsite photo SM H:\A Cooke Cottages \SAO SR.doc Page 5 of 7 06/01/2010 documentation of the offsite north wetland conditions along with visual observations of offsite plant types, quantity and quality. b) Environmental goals and objectives that describe the purposes of the mitigation measures. This should include a description of site - selection criteria, identification of target evaluation species, and resources functions; To paraphrase Sheet W -1, 1.1 the wetland creation area will provide greater floodway attenuation and ecological benefits while being aesthetically pleasing. The mitigation goal is to create a high quality emergent wetland area with seasonal inundation and a diversity of native plant species. c) Performance standards of the specific criteria for fulfilling environmental goals, and for beginning remedial action or contingency measures. They may include water quality standards, species richness and diversity targets, habitat diversity indices, or other ecological, geological or hydrological criteria; Performance standards are detailed on Sheet W -1, 5.2 and are based on hydrology, plant survival rate, and limits to invasive species coverage. d) A detailed construction plan of the written specification sand descriptions of mitigation techniques. This plan should include the proposed construction sequence and construction management, and be accompanied by detailed site diagrams and blueprints that are an integral requirement of any development proposal; Sheets W -1 and WT -1 provide construction sequencing, management, and planting diagrams for the project. e) Monitoring and/or evaluation program that outlines the approach for assessing a completed project. An outline shall be included that spells out how the monitoring data will be evaluated by agencies that are tracking the mitigation project's progress; Sheet W -1, 5.0 explains that a monitoring program is required for five years. Performance standards are detailed above and include monitoring or vegetation and hydrology. Contingency plan identing potential courses of action and any corrective measures to be taken when monitoring or evaluation indicated project performance standards have not been met; A contingency plan is detailed on Sheet W -1, 5.4. Possible contingency actions are described. If the performance standards are not met, a detailed contingency plan will be developed and implemented with City approval. g) Performance security or other assurance devices as described in TMC 18.45.210. An assurance device, detailed on Sheet W -1, 5.3, will be required prior to public work's permit final approval. RECOMMENDATION Staff recommends approval of a 50% reduction in the eastern buffer for the Type 2 wetland and the approach for mitigation that is outlined by Sewell Wetland Consulting and Ken Large, Landscape Architect. Approval of the attached, red -line plan set shall be subject to the following conditions: 1. Work in the mitigation area will only occur during non - flowing/saturated conditions. The preferred time for construction is in the dry season (June - October). 2. Prior to the issuance of the Public Works permit: a. Provide a cost estimate of the labor and materials for the five year monitoring requirement for the City's approval. b. Submit a performance and maintenance security guarantee (bond or cash assignment) of 150% of the approved cost of labor and materials for the project to guarantee performance, maintenance, monitoring costs and correction of possible deficiencies. The guarantee may be held longer than 5 years if the SM H:\A Cooke Cottages \SAO SR.doc Page 6 of 7 06/01/2010 performance standards have not been met or the mitigation has not been successfully established (TMC 18.45.090F7 and 18.45.210). 3. Monitoring: a. A monitoring report, prepared by a qualified wetland biologist that documents performance of the wetland/buffer area in comparison to the performance standards, shall be submitted to the City on an annual basis, starting approximately 1 year after completion of the construction. b. The monitoring report shall include evidence that this project has not changed the hydrology of any downstream, off -site wetlands. Prior to the fmal inspection of the public works permit the applicant shall provide baseline off -site hydrology conditions and the future monitoring shall be compared to the baseline conditions. c. A qualified landscape maintenance contractor is required to carry out the maintenance for the five year monitoring period. INFORMATIONAL ITEMS 1. No modification to the enhancement plan or the plantings shown on the enhancement plan shall occur without the prior written approval of the City of Tukwila Department of Community Development. NEXT STEPS 1. Obtain a Public Works grading permit. a. Permit approval will require compliance with the red -lined and approved plans attached to this letter. b. A pre - construction conference will be required with Planning in attendance. c. Include a note on the Public Works plan set that this project is to comply with Geotechnical Engineering Report, by GEO Group Northwest, dated July 17, 2008. d. ESC measures as recommended in the 1998 KCSWM must be utilized. e. Project is to comply with the Infiltration Evaluation Report dated 8/11/2009. 2. Provide a copy of the USACOE permit for the files. 3. Prior to final approval of the public works permit: a. The applicant shall have Ken Large, Landscape Architect submit a "Certification of Planting" to the City of Tukwila. The Certification shall note that the planting has been completed per the approved enhancement plan. The City shall not conduct any inspection until this certification has been provided. b. The applicant shall record a "Sensitive Area Easement" with the King County's Recorders Office. The City shall review a copy of the easement prior to recording. c. A detailed monitoring program shall be submitted for the City's approval. d. An as -built drawing/report will be submitted to the City upon completion of construction (this forms the basis for monitoring). e. Submit a copy of the contract with a qualified landscape maintenance contractor who has been contracted to carry out maintenance for the five year period after planting. Attachments have all been red -lined and stamped "Approved" by the Planning Division of DCD. a. Critical Area Mitigation Plan Sheet W -1 prepared by Sewell Wetland Consulting. b. Critical Area Mitigation Grading Plan prepared by Blueline Group. c. Critical Area Mitigation Planting Plan prepared by Ken Large, Landscape Architect. SM H:\A Cooke Cottages \SAO SR.doc Page 7 of 7 06/01/2010 • Cottage Housing Dev. Cooke Creek Meadows Proposal for Design Review Technical Comments #2, Miscellaneous Comments: 1. A Public Works permit for grading is necessary after the buffer reduction is approved. 2. Prior to commencing work, please provide a copy of the USACOE permit. 3. This project must not change the hydrology of any downstream, off -site wetlands. It does not appear that any hydrological studies have been done to determine the effects of the excavation or the height of the proposed weir on downstream hydrology. Provide information that indicates the hydrology off -site as a basis for future monitoring. Response to Comments #3: We have designed the drainage to not increase down stream flow as indicated by our Civil Engineer's comment, see below. We have reviewed the question of providing an offsite hydrology study. We have concluded, as previously discussed and agreed with the,City, that due to complexities beyond our control for offsite work we will provide onsite photo documentation of the north offsite wetland and on site visual observations of offsite wetland plant types, quality and quantity with list. We can then add this to the 5 year monitoring requirements and provide an annual report on offsite wetland condition. With that if there are hydrology issues our biologist or engineer will recommend weir height change to address any issues. Ben T. Rutkowski, PE Project Engineer, BLUELINE Group states, we designed the developed site using flow control BMPs to reduce the increase in developed peak flows as much as possible. In the existing condition, all onsite runoff drains to the onsite wetland. In the developed condition, the increase in peak flow (100 -year) to the wetland is 0.096 cfs. Since the City has asked us to limit the increase in downstream flows as much as possible, we stated that the wetland volume should be increased by 655 CF which was done. This additional volume will provide sufficient storage during the 100 -year storm event so that there was no increase in flows to the downstream conveyance system. We addressed the site drainage purely from a flow control standard, not a wetland hydrology standard. Our plan is to use art biology and minimalist engineering science to balance the needs of the wetland, capacity of the rain water from the site and the upstream water source to limit the downstream effect of this approach. Sheet GP -01 1. Sheet W -I indicates that the foot mat of the Reed Canary grass will be removed from the existing wetland. The proposed depth of excavation for the removal needs to be show n on the grading plan Reed Canary grass needs to be excavated to a depth of at least one foot 2. The removed Reed Canary grass root mats must be taken off -site for proper disposal. This must be indicated in the excavation contractor's spec drawing submitted for the Public Works grading permit, Response: We added a note on sheet W -1 and on the grading plan that "All reed canary grass will be dug out and removed to a depth of 12 -24 ". The location of Reed Canary Grass will be staked in the field at the pre - construction meeting to reflect site conditions at the time of excavation." Sheet W -1 comments will be address by Sewall Wetland Consultants. Sheet WT -1 comments will be address by KLLA. Sincerely, Todd Smith, CEO Cooke Riverside Properties, LLC. March 15, 2010 RECEIVED MAR 1 9 2010 awmuNrry NW 1/4, SEC 15, TWP 23N, RGE 4E, W.M. CRITICAL AREA MITIGATION GRADING PLAN 1 SCALE: 1" = 1 0' 5 10 REED CANARY GRASS NOTE ALL R® CANARY CRASS MILL R BUG OUT AND REMOKO TO A OEM Cr 12-24' PC LOCATION OR REED GNARY BRASS MILL BE STARED N PC Fall, AT PC PRE -cons 0C11O1 YEEINC TO REFLECT 9TE CONDITIONS AT DC RYE OF EATARA 76W. Oran rnx slant wow 4 WETLAND STORAGE VOLUME ELEVATION (PT) SURFACE AREA (SP) RIC EBENTN IOLLMC (CO TOTAL KaLQC (6) 3200 1528 1,521 4.61 5150 2731 1,242 2703 57.00 2236 031 1.662 50.50 1.572 626 025 50.00 002 200 200 9.50 204 =PPM STORAGE LOUPE 55 ALY216NAL 9R 572492 " 633 Cr (700 YEAR 24 NOUN STORY (1012 554 A 57505OR BY RAW GARDENS) MAW, SRAR.IGE MAME 1.662 CR RAIN GARDEN TABLE STORAGE 4aw[[ (CO WO 90 3 30 5 0 W C=0 i c■ii I6M4A LL — to ow II: 1492: Rpm P al LAMM IT AMC, ENCIVECR: OE90NER: PILYLOI >L0 OAT Nom. JOB Ai UmotTO: 08 -068 093E1 MAME: GP -01 551 7 51 I AvOUrs r 7\ .30 Rube • 24 1¢080 nmdrArao■ • /0 698 • 4f 640#4 - /A R/a ' N 61MP 871105 sue awasee 2&EI 62- .44,41 a1n4 • // 44012 - 4693 ROS a1� 7 93 rya SECTION AT WIER a • t --� 2$y�r- i __ a �1AtSFR- �I d 1.14, TuT: �S � RAGGING //- METAL FENCE POST r ORANGE PLASTIC ICONSTR • eeA USE ZIP 5TOAttACM / FENCING TO WIDE AND POSTS • /2 Mhai • 3 .4ld.G 1464 51EEL WIRE 000000. - c C00000- I L7�c.- X00001 -JOE C'-�= D- LJ_jooC 0 0001 000'OJOOOoo = 000 oo o=000. e 00 I=R_Lidi -11= 11= 11!= 11= 11= 11- 11= 11- 11 11= 11-= 1r=11= 11 I .42 . 2 pw. • 2+ ..143 lf;��1► T►i 6 ' 0 e 0vRLae41rsa / R,•.C,6vt �� v c n •CI PLANT LIST /2 1411./ • K. /18* 3 pa,' • /J .QUAD • I CORN • 10 20013 6 MI. n immem,Ime meat. Nam Mr 1 ACMAI Ama m6yDO 4A✓M. Ia `m A .4 "193. a 11M Rm.6dCm DaaMm rm w 8 ro• ...wen 464. w..am 1. -.. �6.. aa...w 6 CAS Cam. Ma 6.m AA.ma mm Ir11•160 0 1 et 6m m HIM.. 6W Ma. m.l.l. • nn D. . amwaill 81^6 mar 1I�i•w.loMal rtm. ..8613 6 IRA% .•..A. P,aaax.�. �:" Sae m if., Math pain. N 3.18 SMIM *maw 1a.a. • AMC W Mb .m... iam 13.1f Boma W le M.e.O... • .n wee. _ 3p.>. 4. Wemvua.asl.a -' IM SYM e..em3 ,,,m/maw Ir41.Wa 1 gala m. ...an.. 6"...1444. 1a DIAI a..e m4em ad. 1r.w.da ,e 3 1m wa • 10 20013 6 MOW „.. a.. R•+..A.d.a 12-11r laasie m aaa 4ama Onm Cum NR Cam Mamama 18,..m 6. mpe,,,..m 4 MUM 44..6.,, •Md•am... i2;16- m■ M 1:.7.' M p.m 1x MAN 584* r I.* 1 d M. ^, 4.a 6 PAM Ram em, .wan. 1 Maw m. al. or 4.myp .. 33, 6Di halm we a a pm..., x . � "a„ o . pm. 35 uY¢ M. M. p a w * 11 Balls a taw *Mg N 3.18 4 *maw 1a.a. 0 ] CUM 11 - .Pd A Com aM .. - C.. -. la6e.- 1 m.a4e .w4m Taa NOTE: LI FENCE WILL BE REMOVED BY OTHERS UPON COMPLETION OF BUFFER RANTING EXISTING SHRUB AND TREE PROTECTION DETAIL Au 86088 8684081 PFmIRC 3NeRLwBa 0MLLB4 Dgi6 BTPAMDq CRITICAL AREA MITIGATION PLAN/ PLANTING PLAN 161 ca, , Gnaw MN MM. M. CaaMla saMa yaw IDbm Onm Cum Maaa mew 1 Ow cm 113 1 P01.10 5m6m. /e6.a..m+n m.a A.. Ia6am IaD.m 4 4,. Im P.P*R+4 IBM we [An m 20 CAR ...W4. 406444 58 'AM ,88 3 66 Wee ala 33, scam D b mem na6 .ham maw maWw..lranw aa y. 6,3 8 WO Ivry bawd nah 4..84x8646 Jam 444.4...., M.o. W. `..:.16.x.• N 3.18 Mm64wm L.a...-..wm Ma a.: et a I1MU1 vw•exwu. C.a,d.. Bag m..9y. 13.- If WS cm. �M ■ N.�.... ..°" .m ..r Cm laaam Ban .....w • IS 0.1 6a, in mm (MM..* Boa am . M 4Ir.Ir aen, TREE REMALE ENf TABIFAL, TREES REMOVED REQUIRED NUMBER OF REMCEAENu TREES TREES. S. CALIPER ALTERS 08.E 4-(41.11,E11 ALDER 6 TREES z TREES TWO' BROADLEAF TREES • TREES TOTAL 12 PEW TREES REQUIRED Sw.a. •6.2009 LEGEND %S S.o ooa�. 1 .w 4 m A ................. ,,,,. 8 ¢ T1eS 86 am ae 7.wW s . 614 Pme a ®awm a.a me ▪ � 5rrwcw671AMI AllDAan'x `'....... CREATED WETLAND BIITPER. 50 rm N me ant ld13• am.m {--T--} ROILED MATERIALS IIt A u.:,. C�a� pass m1asm.: lx..,m.. . 'Um. So.. Mma.: i. am. ma P......mim.Fi- eRail m6amwhoa ..ivy and Im844 cam. 6m ad MINM6wnwaemm14. R you .4• Imam. Pw..b rem om Rail. T. meadow . oaf Ig ad Swam • 60111..a!,•111,..... F 1,4e.. pm *I 14 aem•300.. 3•• •∎4 6 .dm S 1.33334 d*144. elad*a648693. A w ei. w _ AR Y.1.:66.d.i. F4 add .m: MObx.D pea ,4 Lw- ".•m.pwu1f00 • .1 0. C .Tadi) Fine n'tlia...P3Y 4. .m. Fu6M M arm. Guff• R� D e06.ma MI 05.444 -.4..P •mini p w... . .y 0 lj La co Q o m3 W 2 of OfV gh UCH WT -1 0.0 341111.31014 CONC.! ASO 00 1.1 141110 VIM 3 31 46460 00.7 440 0111.4.3.3 Ilasf 63.0. 2... p.0 3,11... pruen .063.116 Is 112 4.11.. caw aarnotstee aka/ ■■■ vellas velisedkvarn IIIAniogy (or emend es plmu .01. ,Ilmra ••■ p rosy 040044. • a: !Owe ...Us I wee.i. • ...au dwe ...sae. Dewy...sea. • cu.. *awl milluer.1 41.1ephle no pwita. ay n *gam OM.* sr meta o a/4*w mole. pea a m.legia 0.1.407 344 3.41.4*313 443141'114.43.33343 4334 1...6 .......mt••■...,14,6•11*.•••••..,.....••■•■•1.1.411,•en•••••.••• 4.0.44 00 21060.0 ess. .00.1em 2. 3.1 11.1....4 3010.4 044-11404,11011161.11611.1•1131-410.16 .3034 So 1. • 0.21114.0.3 3410.. Q60 1.16 51111.T.Y. 4104. 1 6311. 13 2 .14 2O2S3011•211016 06210111, .4114 04.1.0 2 1 21fl Comumno Van.. Ion.. my, nay. 2 4 (lacy Yd.. 2 34.3.46.41. 4.0 66104 2 0.1033.44. M.. Ana 17 1.1.3. 113 N. ma a*, • • • *W.I.,* 714 SI 1 Vgpsee 1.1 .36.0 II ST AVM." 0. 34 131.3 10* 3.0 Irlw. .1.4•1 1.5wase:7111711:: PI•••■• " 2 Ns ram Om me. mane mane *pone tr. es la( noquan pen.. 33 3.44131141.001.01.4.004.1.44419613.311.11.1.02 3 3 7 a. 10.14 mema a17 11, of Jo 011 I. 1.03303 * *may *Nye 12 I MI.... ▪ Ma gye 000 Ma N.. any 4. 4.04 034.30.1. 2 La .......1134113 AMY 431 01.34330141. • .,••••••••• ••• ••••••••••• ......•••■•■•■••••,••••*•■■,.. e,-- 41. .....4 • .... ........... - 40........................................ .................,....................,....... 44 0..134 33.... ph. 1.01........................4 .... AY.. ........ ,......,=,.d............................................ c.........1 ..................* 0.41011.1142411031.1 4404 13.60 •,. 2J1 I... 4.110 130 Om. 43 0 641140 00 • 1.111.3 • Itivems or Frt.. fay. 2 11 ..........1111.1016.1. 2,2 1.1 110.010.4. a' 3.1 2 11.0441.2 43 eic. or aalishosil,..a.1.1.aaract Yes. 0.1143.4 • 4.310.101. 3 43 TY plow • • 144 ••■•■••••.- T. 0.600.4..6110 1.006/ 4 1 0 ;um =out ais per ec greyed p1....• p-valcas ceemenwn. magnum ...a 113.0.111040 1.0•1 Err. 3.03. ra.• 0066111•00.03.0.0.0.100 6.4 n▪ o 0.0 0664.006. ..0.13. Itnx Am. II1e L....I., ...on. !Iwo she I • Or elan pr pal, e rspne • dm Ns cp. ...A.* Om ar.eas ores., ...01.e pbned yol comm. mem., pnalma. wart Ira ma, 'am./ 001.33 33 431. .00 .4.. 1.401.4.03.0.414.1. Igairem ".:11' .1141416434.01174.441 .21004 461.0 11.3.4.2643.104 4.11110.13. .430 0 Y... ay .6 .1•41.310.....11.003 .13 *nal • ..nle n...•••■••••••• • •■■■■ • • •■• •••mmtb,,,,.......••••,11t. arm*. al, rpm. • a, • dm*. •• 1104100.41....4 3110".2 3 4 ye 01.0 aye. 1000.6. 04.112 0. .31 .13.112236 wp1.0.6.1. 433.0.64 40.00013.0 44040. Cyl ....nen.. do • eka.nA raMIWIran Y. 34.0 0.400.4 4.1 .14.41,11.4.4.1 001.11 011.1 17 111.11001.11.1411. 2„.. 4 11 114. my, a.. yip. plan 43. Nay amens, O ,013.04 1041. T. yen.4013.4.2 ay. . 0 .4.63 24...6314. 11. 22.221.2*122.22 12 1.1.00 0.312 NO..., VAN. • /11 lay* 0104 .0164.60. 03.3.06.1.1133.1.4.13.3. 6136.4.1.1 *Y. 4.3. Imo 30.1.1.• 3.0123.. 110,12. arprer. inporeowc ral■ 0.•• L 101.-mone a elapp.ega fill a *agora.... 11.3.4621.4 .1.31.64 Ine me* nee lee eatt......e. nresa.o. 0 I. 1-• 044.13.6064 • 1.6.4111.23.0.. 04044.1. a. a. Www1•11111.1• 111 222 ••30 .0.6 63 0.420.3.0 Me Y.. • y of 0.14...4 43.0.143 430030 L22 rwowtweewwe It. ea th. 106.64.111.4.0.1. ....1.11.041• , moms. 33 4111111 0110311.1 41341104 • 51. rut taxi toN 722 Ito •••••••• ••••••••••• a • • text...NI 0.1...• 400.1103 44/ 33 4.401441.334436341 446 Yr. 3 12 1.1.46.14.......00 3.11. 3.6.4004 mom a WM... dm. 4.313 Y. O I1m222,22fl,. . 1▪ 3.111011113.04111.1.1.3 3 13 20 U.. Co.. .111.3 gr. 3111100.10 3.64 441.613. 4141644313 .10 4 11 1.1.0.4.03.134 .000 2..2.30.1..34101. .64.401440143411.13.146,011,., 31 11.426141413111103 j nmnqi after t...■ plmunp sr. cmdmno 311 AO be ..01.1 in rt. pl.. vAteJ•le 1360 ph. eau. ■11.01•CI .3.06 mom 44.044.144. Y... 61 4 1p101 oa 3.2.1 All p.n... .11 4.03. to ...43 Ay 1.1010. STIMItti 20.0 31.00. . y numuls.11 nay YIN 00100, 1.113064134 13. 1.11.11301. 04......,3160.000.10..........13.4 2 3430 an. 4 14 1603.1.11.41314.3.3.1.14 4.60 pan worn. n. nal 1.0.1..............1.331163.324 .0 ray. ya 123 All atery po. 0.11.013.1114 .1 .......11.4 .3 4.0. By. 20.03.1114 .011.0340.1 460,30 6.. ..... 011. 41.31.1. 6...........0.a............... .114 11.111.1.0. 4.............111.133.1164.0.0010 ............1134 0........230.1. 43 11.41.1201 OW 11162. VI.. 04 000140441 IP.. 04 2.111.2.m. P. .111. 6.43.1.130 0..• In.. 6.600.3. My my.. Y.. 3.1.1114. Y. No... 4.131 .00.1 yam Y... robe,g....r.... .../.....1.64.............................................. 3 2 3 434.1114 'dm I.Nly • 41114.4304.3 010.1-461 001.14 0.0.0.1.4343 ,•••••• • • • • or.... *ad e • lb • •••,.....••••••=m ••=0.1.•■•■■•=......., /*/.• • • ••••••, 3 2 6 411.11.61.13.11.06.0431.....1.11.61..........3.4...y. nn.s.osa ▪ 006001.113 64. 4110 49.114... Maar, 31.0 0•• 430641.3.0.1 4411 Y.. pvf mem. ate: waItt/talb an • a e■■■■••■•...rn sl.bc wag C my.= • ons 1.133.03.0.04.40. • .4.110 0.10.16400. 2 2 7 12211....21040 a.. $0•30 Ye. The 4.07 ...446 Joy 343 110.3.3.00.30 I.. 14.-sen. Wm I *It dean. In= Ote m.o... are worry .x46 tams hop 141NIMI.M IS' OlamrIER r Lae. CND INISPor 0 OWL' 13' .11•11 115 lx DIANL1r. 6•IFT 1.3 LF LOKI:Err .0CALIKAN I' PICK) AWL cr MIL. • HORIZONTAL LOG SHRUB PLANITNG DETAIL Ayr rox, GI6 waxy 437,27 22M2S TREE PL4NTING DETAIL ACT r0 SCALE 12 22171 0132072 SNAG TREE 212274(0 1.3 Ce Cr1K.rrE 111,31.1, • •••1LA• • 113 IN M.( 1C. VIAE RO:r • •• ,14•Il • CABLED STUMP 11Tair.17.1Laml.r1.11-1„-„- [mill wan. . , - . 4 4:.rw WO. No•OP 10 .0 R. Mb* .0• 000. CI ITICK CONIFEROUS TREE FKAIVI7NG DETAIL NO72125CNI din FOR NOW MO0411001 LOW.," Lir 1' r1InK1.4 (204141746722 WETLAND SIGN DETAIL Mar re, WALE Sewall Wetland Consulting, Inc. 272472222237372272212271222271223742723025 is,RE oma 17.4.0 YA MAR 1 9 2010 COMMUNITY DEVELOPMENT (01/20/2010) Stacy MacGregor - RE: Tdd Smith Project Page 1 I From: To: Date: Subject: "Printz, Jacalen M NWS" < Jacalen .M.Printz @usace.army.mil> "Stacy MacGregor" <smacgregor @ci.tukwila.wa.us> 01/20/2010 2:53 PM RE: Todd Smith Project Stacy, We have currently requested a cultural resource survey to be provided by Mr. Smith. Based on our review, it has been determined that the proposed project is located in an area of high potential to cause affect to historic properties due to the location and the nature of the proposed work. Thank you, Jacalen M. Printz Project Manager, King County Regulatory Program U.S. Army Corps of Engineers - Seattle District PO Box 3755 Seattle, Washington 98124 Phone: 206.764.6901 Fax: 206 - 764 -6602 jacalen.m.printz @usace.army.mil Original Message From: Stacy MacGregor [mailto :smacgregor @ci.tukwila.wa.us] Sent: Monday, January 11, 2010 3:46 PM To: Printz, Jacalen M NWS Subject: Todd Smith Project Hi Jacalen, RE: Property at 13325 Macadam Road S Would you send me some documentation that the Corps is requiring Todd Smith to obtain an archeological site survey triggered by his request to excavate in the wetland. I would like to have some documentation in my file that the Corps believe this area has strong archeological potential so the City conditions his permit appropriately. Thanks, Stacy Stacy Stacy MacGregor, Assistant Planner 206.433.7166 City of Tukwila, 6300 Southcenter Blvd, Tukwila, WA 98188 Monday- Friday, 8:30 am - 5:00 pm P Please consider the environment before printing this e-mail December 4, 2009 • City of Tukwila Jim Haggerton, Mayor Department of Com;nunity Development Chandler Stever 1715 223`d Place NE Sammamish, WA 98074 TECHNICAL COMMENTS #2 Special Permission (SP) Wetland Reduction Decision L09 -012 Tree Clearing Permit L08 -065 Todd Smith PO Box 97193 Tacoma, WA 98497 Jack Pace, Director Subject: Cooke Cottages: L09 -012 Special Permission Buffer Reduction; L08 -065 Tree Clearing Permit Additional Permits: L09 -013 Public Hearing Design Review; L09 -020 Short Plat Dear Mr.'s Stever and Cooke: The City has completed its review of the above permit applications. The application was submitted on March 31, 2009, routed to City departments for review, and deemed complete on April 24, 2009 for the purpose of meeting state - mandated time requirements. Technical comments were sent to you on June 16, 2009 with a response received from you on September 22, 2009. You responded to the permits for a SEPA determination and buffer reduction. The City issued a SEPA determination of non - significance on November 18, 2009. This response is to the plans submitted for the buffer reduction and tree clearing permit. The project was reviewed by the Public Works and Planning Departments. What follows are their comments. Please address their corrections on the submitted plan set or in a written response as applicable: The proposed plant palette for the wetland and buffer provides a nice diversity of trees, shrubs and forbs /emergents that should greatly improve wetland and buffer function and be attractive and interesting for residents of the cottages who use the path. It also provides good foraging, future nesting and shelter for birds and other small wildlife. The City is very concerned about the future success of the wetland mitigation and enhancement given the presence of Reed Canarygrass in the existing wetland and on `upstream" properties. In addition to the following comments, the plan set has been red -lined with additional comments. Numbers adjacent to comments on the plan set correspond to this comment letter. ALL INFORMATION NEEDS TO BE SHOWN ON THE PLAN SET SO THE CONTRACTOR/INSTALLER HAS ALL OF THE INFORMATION NECESSARY TO COMPLETE THE PROJECT AS APPROVED. Miscellaneous Comments 1. A Public Works permit for grading is necessary after the buffer reduction is approved. 2. Prior to commencing work, please provide a copy of the USACOE permit. 3. This project must not change the hydrology of any downstream, off -site wetlands. It does not appear that any hydrological studies have been done to determine the effects of the excavation or the height of the proposed weir on downstream hydrology. Provide information that indicates the hydrology off -site as a basis for future monitoring. SM H:\L09 -013 Cooke Cottages \Tech Comments2.doc Page 1 of 4 12/04/2009 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone 206 -431 -3670 • Fax: 206 -431 -3665 Sheet GP -01 1. Sheet W -1 indicates that the root mat of the Reed Canarrygrass will be removed from the existing wetland. The proposed depth of excavation for the removal needs to be shown on the grading plan. Reed Canarygrass needs to be excavated to a depth of at least one foot. 2. The removed Reed Canarygrass root mats must be taken off -site for proper disposal. This must be indicated in the excavation contractor's specs /drawing submitted for the Public Works grading permit. Sheet W -1 1.1 MITIGATION CONCEPT and 1.2.0 MITIGATION GOALS: These sections need to be fleshed out to meet the Mitigation Standards of TMC 18.45.090F. Plans need to include: a. Environmental goals and objectives that describe the purposes of the mitigation measures. This should include a description of site - selection criteria, identification of target evaluation species, and resources functions, and b. Baseline information of quantitative data collection or a review and synthesis of existing data for both the project impact zone and the proposed mitigation site. (This relates to Item #3 under Miscellaneous Comments, above). In addition to the red -lined comments on the sheet, revise the sheet as follows: 1. Under 2.4 Clearing and Grading, address the following: Given that the topsoil layer will be removed in the existing wetland during the Reed Canarygrass root removal, soil amendments will be necessary to ensure plant success. Indicate the proposed soil amendments in the existing wetland. The owner's response to the City's comments on the conceptual wetland mitigation/enhancement plan indicated that soil will be amended in the top 12 inches of wetland to retain water. The plans state that topsoil will be imported into the new wetland area. It is important to incorporate organic materials into site soils to improve water retention and support plant growth. Whatever soil imports or amendments are proposed, they must be specified in the plans. Imported topsoil or soil amendments specifications are to be provided, including at least 20 percent organic matter. 2. Under 3.3 PLANT AND HABITAT MATERIAL INSTALLATION, add the following: a. Planting area shall be tilled to a depth of at least 18 inches. b. Till in three inches of compost across all landscaped areas. Mulch is to be kept away from woody stems and crowns of perennial plants. c. Planting pits must be only the depth of the existing root ball or else the bottom of the planting pits must be compacted prior to planting to insure there is no settling. d. Root balls of potted and B &B plants must be loosened and pruned as necessary to ensure there are no encircling roots prior to planting. At least the top half of burlap and any wire straps are to be removed from B &B plants prior to planting. e. Where there are existing tree roots, incorporate soil amendments by hand. 3. 4.1.2 f Revise to say: "Remove all invasive plants (ivy, reed canarygrass, blackberries, scotch broom, etc) within the mitigation area. Invasive plants should be controlled by hand cutting or grubbing out by hand. All debris is to be removed from the site and disposed of in an approved landfill." 4. 4.1.3 i Revise to say: " If hand removal is not effective, the use of herbicides must be approved by the City, in writing, prior to use. Only certified personnel will be allowed to use herbicides near critical area. 5. Under 4.0 MAINTENANCE PROGRAM, add: The City will require evidence that a qualified landscape maintenance contractor has been contracted to carry out maintenance for the 5 year period after planting as a condition of final PW grading permit approval. 6. Under 4.3 WATERING REQUIREMENTS, add: a. 4.3.3 A temporary irrigation system is required for three years. 7. Under 5.1 SAMPLING METHODOLOGY, revise: The City will require that the annual monitoring of the wetland and buffer mitigation /enhancement is carried out by a qualified wetland biologist (per the City's Sensitive Areas Ordinance). A detailed monitoring program shall be submitted for the City's approval prior to final PW grading permit approval. An as -built drawing/report will be submitted to the City upon completion of SM H: \L09 -013 Cooke Cottages \Tech Comments2.doc Page 2 of 4 12/04/2009 • • construction (this forms the basis for monitoring). A monitoring report, prepared by the biologist that documents performance of the wetland /buffer area in comparison to the performance standards, shall be submitted to the City on an annual basis, starting approximately 1 year after completion of the construction. 8. Under 5.2 STANDARDS OF SUCCESS, revise: The City will require that the performance standard of no more than 10% invasive species be met every year, not just in year 5. 9. Under Planting Details, modify: Provide a specification for "mulch ". The City does not require straw for spring planting, wood chips or other mulch may be used. 10. Under Wetland Sign Detail, modify: The wetland sign needs to specifically say to contact the City of Tukwila at 206 - 431 -3670. Correct the phone number shown. 11. Under 5.3 CONTINGENCY PLAN, review and add: The Director will require a performance and maintenance security guarantee (bond or cash assignment) of 150% of the value of the labor and materials for the project to guarantee performance, maintenance, monitoring costs and correction of possible deficiencies. The guarantee may be held longer than 5 years if the performance standards have not been met or the mitigation has not been successfully established (TMC 18.45.090F7 and 18.45.210). This will be a condition to obtain a Public Works grading permit. Provide a statement of the value of the labor and materials for City review. Sheet WT -1 In addition to the red -lined comments on the sheet, revise the sheet as follows: 1. Under Plant List Table, revise: a. In the table of Emergents and Herbs, it is not clear what is meant by "sprigs" — please specify whether this means "plugs ", "tubes ", or "bare- root ". b. Also in the table of Emergents and Herbs, the size of the containers for Lysichiton and Iris need to be specified. 12. Under Legend, revise: a. STUMPS: Stump specifications: 10 — 14 feet is too short — use the specifications provided for snags by the wetland biologist (6 ft below ground and 20 above, per sheet W -1). Eliminate the duplication of the specifications for snags. b. HYDROSEED MATERIALS, revise: The proposed hydroseed mix is not appropriate for a buffer restoration and additional native species should be added. Remove colonial bentgrass, perennial rye and clover and add: Festuca roemeri (Idaho fescue), Elymus glaucus, possibly Deschampsia elongata. Consider adding forbs to the seed mix such as: Achillea millefolium, Ranunculus occidentalis, Eriophyllum lanatum, and Viola adunca. 13. Under Critical Area Mitigation Plan/Planting Plan, review and modify: a. Plants need to be appropriate for the expected hydroperiod in the wetland. Hydroperiod information has not been provided (i.e. what water levels are expected throughout the year to support proposed vegetation). Have your wetland biologist work with the landscape architect to determine the likely hydroperiod and then the biologist should recommend the most appropriate plants for the different zones in the wetland. The City has concerns about the use of the following proposed plants in the wetland. i. Iris tenax prefers dry conditions and is not appropriate for planting in the wetland. Iris setosa would be more suitable for planting along the shallower parts of the wetland. ii. Aruncus dioicus generally grows in moist areas and on the edges of stream channels and not in wetlands. Some of the proposed planting areas appear to be in the deepest part of the wetland. iii. Boykinia major generally grows in moist areas and on the edges of stream channels and not in wetlands. Some of the proposed planting areas appear to be in the deepest part of the wetland. iv. Scirpus lacustris needs permanent inundation. It does not appear from the grading plans that the wetland will be inundated all year round. If this is the case, an alternative plant that can tolerate being inundated in the wet months and saturated soil in the dry months. v. Sparganium emersum grows in standing water and may not survive if the wetland becomes dry in the summer months. Again, it is important to ensure that the selected plants are appropriate for the expected hydrological conditions in the wetland. vi. Juncus balticus is not appropriate for this site — it needs alkaline conditions. SM H: \L09 -013 Cooke Cottages \Tech Comments2.doc Page 3 of 4 12/04/2009 • • b. There are three plant circles marked with an "H" to the west of the existing wetland, near the southern boundary of the property. There does not appear to be any label or corresponding symbol for these plants. What is being proposed? c. Ceanothus velutinus requires sun, but it appears that the areas proposed for planting it are in the shady areas along the stream edges. 14. Include the tree replacement table on the landscape plan showing the trees removed and the quantity of replacement trees provided. 15. Specify the materials to be used for the path through the wetland/watercourse buffer and how it will be constructed and maintained. A biodegradable landscape fabric must be used (such as burlap, cardboard, or other alternative) as the base. What is the width of the path? Include the path design detail on this sheet. 16. Revise the "existing shrub and tree protection detail" to reflect red -lined comments. NEXT STEPS Your next step is to address the comments made in this letter. The comments included in this letter address the plans as submitted. Once you have addressed the comments and revised the plans, resubmit three full -sized plan sets and one small -sized plan set to the Department of Community Development for review. Please respond within ninety days from the date of this letter (3/03/2010) or the City may cancel your applications from inactivity. If you have any questions, I can be reached at 206 - 433 -7166 or by email at smacgregor @ci.tukwila.wa.us. Stacy MacGregor Assistant Planner Attachments: cc. File (L09 -012, L09 -013, L08 -065) SM H: \L09 -013 Cooke Cottages \Tech Comments2.doc Page 4 of 4 12/04/2009 City of Tukwila Department of Community Development Land Use Routing form for Revisions TO: Building: Fire: Public Works. Environmentalist: FILE NUMBER L09- 012 - buffer reduction; E09 -001 - SEPA Project: Cooke Creek Meadows Address: 13325 Macadam Road South Date transmitted 09/22/2009 Response requested by: 10/6/09 Planner: Stacy MacGregor Date response received: COMMENTS The project approvals are now divided into steps. This submittal is to work towards the SEPA approval and the buffer reduction. When these decisions have been issued, the applicant will work on design review and the public hearing. SUcciA kc.tvc-rronl y1 -rS public WoRaS $4auiR.lidiefxrs . SEM treier5 Pvp &I a tvoR`ts ReoulgJ4iti►rrs • 1 %2/09 ❑ DRC review requested ❑ Plan submittal requested ❑ Plan approved Plan check date: Comments prepared by: Cooke Creek •adows Submittal Wetland alliBufferlffeetrdiraD Landscape General Comments referring to wetland enhancement SEP 2 . 2009 6. Any excavation proposed in the wetland must be covered under the Corps of Engineers Egstaietutitlipay also require a permit from Washington Department of Fish and Wildlife (which accepts thelMWPAPINIATand see Public Works comment above). Also, this project must not change the hydrology of any downstream, off -site wetlands. It does not appear that any hydrological studies have been done to determine the effects of the excavation or the height of the proposed weir on downstream hydrology. The wetland biologist should carry out such studies by installing piezometers /shallow groundwater wells. Such a study would need to be carried out over at least a 1 year cycle. • We have filed a JARPA for an NW27. Because utilities are not crossing the wetland we are unaware that other permits are required. • Concerning the piezometer, our biologist, geologist / soil engineer, Civil and landscape architect have indicated it is unnecessary as this will not reflect design conditions. • The Weir will regulate water flow off site to the north as designed to accommodate additional water added by our development. We have designed a variable weir that will allow us to adjust the outflow height of our created wetland should monitoring indicate more or less hydrology is necessary. • See the sensitive area mitigation grading plan for hydrology volume and quantity of water entering our proposed wetland. Also, for additional drainage study see attached infiltration study from Geo engineers N.W. 7. Specify the materials to be used for the path through the wetland/watercourse buffer and how it will be constructed and maintained.. What is the width of the path? • The path will have a base of landscape fabric followed by wood chips to a width of 4 feet. BUFFER REDUCTION /MITIGATION - -L09 -012 Review by Stacy MacGregor, Planner 433 -7166 and Sandra Whiting, Urban Environmentalist 431 -3663 1. Verify that the buffer reduction area has a slope of less than 15% across its entirety (TMC 18.45.080 G). • KLLA confirms: as the topographical plan indicates the slope within the eastern buffer is about 3' rise in 25' for a slope I believe is 12 %, less than 15 %. 2. Mitigation is required in the entire stream buffer for clearing trees without a permit in a sensitive area. Provide one single detailed plan for planting from the eastern edge of the wetland buffer to the western property line. The Wetland Plan states that the area outside the wetland buffer will be planted per the landscape plan. All sensitive area plantings need to be on one plan sheet instead of two. • See attached sheet WT -1 sensitive area mitigation planting plan that shows one plan for the sensitive areas. KLLA has worked with SWC to provide a cohesive planting plan that meets the biologist's requirements. 3. Coordinate between the landscape architect and the wetland biologist. The wetland biologist is responsible for providing the buffer enhancement and reduction mitigation plan per code. • See attached sensitive area mitigation plan, notes, requirements, sequencing and planting details from SWC biologists. 4. The approximate watercourse buffer (100') and wetland buffer (50') and reduced buffer on the east (25') should be shown on the plans, as part of the required mitigation for unauthorized vegetation removal from the watercourse buffer. • See attached Sensitive area mitigation grading plan for indicated water course and wetland buffers. 5. The Adolfson report calls for a split rail fence along the north property line to prevent ATV's from driving through. Is this an issue here? A fence would need a staggered opening to allow pedestrians to access the recreational path connecting north to south. • Yes ATV's and motorcycles have been a problem in the past. • Our plan is not to use a split rail fence; our plan is to use NW shrubbery that grows to a height of 4' -6' within the buffered area and may change outside this area. • I question this requirement for public access. This is private property unless the city is willing to provide something to the owner for the right of way. P.1 Cooke Creek ladows Submittal Wetland alBuffer Reduction • Secondly, we believe this is not a thoroughfare but a sensitive sanctuary to be preserved as you have described in several of the City's comments. Public access will compromise this. • Unless there is right of way that I am unaware of, this request is an issue as I believe there are liability concerns to the owners that make this request unreasonable. 6. These sheets needs to clearly delineating the wetland, watercourse, and buffers, including the added 20' to the south. • See attached Sensitive area mitigation grading and planting plan for added 20' to South. Concept Wetland, Buffer Plan, and Weir, Sheet L0.03 1. I think this sheet should probably just be removed and the unique information (such as the excavation details) should be moved to the sheets by Sewell. It is a concept plan but the concept is getting executed in the subsequent sheets and I don't think this sheet's details are as accurate. If you remove this sheet, ignore the following comments ( #2 -4). • See revised sheet WT -1 for sensitive area mitigation planting plans as this other sheet has been removed. 2. The plants and layout shown on this sheet are not the same as those shown in the Wetland Planting Plan (Sheet W -3). How does this sheet relate to the wetland plans? • See sheet WT -1 for updated Sensitive area mitigation planting plans. 3. No genus and species names are provided, so it is difficult to know which plants are being proposed. All plants installed in the wetland or wetland and stream buffers must be native to the Pacific Northwest and genus and species names must be called out. The skunk cabbage (not sure if it is the native species — Lysichiton americanum) generally needs shady conditions and organic soils, and since these conditions don't currently exist, this plant may not be successful. The iris, if it is the yellow iris that grows in wet areas (Iris pseudacorus), is not native to the Pacific Northwest and is very invasive, so it would not be allowed. Other, native irises like Iris tenax or Iris douglasii would be acceptable but they are upland plants. • See attached WT -1 for updated Sensitive area mitigation planting with species. KLLA has coordinated with SWC for acceptable planting species that meet native habitat and wetland requirements approved by SWC. 4. What is to be planted in the meadow? Is it lawn and will it be mowed? Some of the meadow is in the watercourse buffer, where enhancement is being required as mitigation for removing trees and other vegetation without authorization. Putting a significant amount of lawn in the watercourse buffer is not adequate as buffer enhancement, however, some meadow could be approved if it is composed of native grasses and other native plants and not mowed. • Native NW Grasses and wildflowers that will be mowed very seldom, once or twice per year. Please note that most of this area is bare dirt however most existing shrubs and small cherry trees will remain in and around the meadow area. Conceptual Mitigation Plan, Sheet W -1 1. The enhancement area continues to the western property line. • See attached WT -1 for entire area. 2. The deck off building 7 appears to encroach into the 10' buffer setback. • This encroachment has been removed; see Sensitive area mitigation grading plan. Wetland Creation Grading Plan, Sheet W -2. 1. Show existing wetland boundaries so they can be compared to the proposed boundaries. • See attached WT -land Grading plan for boundaries. 2. The plans by Ken Large (Sheet L0.03) describe the increase in wetland capacity. Is this volume agreed upon by Sewell Wetland Consulting? State the volume increase on this sheet. • See attached Sensitive area mitigation grading plan for water volumes. • SWC helped craft the current wetland shape and design to make shallow and diffuse water speed. SWC had us adjust the weir height to elevation 50'. • We have had GEO NW calculate absorption rates to determine appropriate size and characteristics of this area. Their analysis and data sheets are attached. Thus his recommendation and SWC was to change the watercourse to make the area work as a wetland. P.2 Cooke Creek ladows Submittal Wetland a•Buffer Reduction We will also provide some mitigation to the top 12" of wetland planting soil which will be designed to retain water. 3. Detail how the storage created will correspond to the increased volume through enhancement described in the TIR page 4 -8. If infiltration is not able to occur (since the geotechnical report says the soils are not suitable) does this proposed volume make sense? • We have had extensive discussions with GEO NW and SWC and KLLA to determine how to make this site work for more beneficial wetland results. As the earth is excavated, we will scrape to hardpan, store separate to build the north edge of wetland. We will then amend the good soil at the 12" planting base above hardpan for better wetland water retention and hydrology. The heavy glacial till soil will be reused to dam the north end around the wier. Planting Plan, Sheet W -3 1. This sheet could be combined with W -4; there is some redundancy in these comments with the comments for sheet W -4. • See updated WT -1 for single plan Sensitive area mitigation planting sheet. 2. Include in plan set: irrigation, tree protection measures, and planting guidelines. • See WT -1 for plant protection measures, See SWC Sensitive area note sheet for planting guidelines and temporary irrigation. 3. Add the "Landscape Notes" to include the following or put on Sheet W -4: a. Planting area shall be tilled to a depth of at least 18 inches. • See SWC recommendations on the Sensitive area mitigation notes as this requirement may not be necessary with existing upper soil conditions b. Till in three inches of compost across all landscaped areas. Mulch is to be kept away from woody stems and crowns of perennial plants. • This soil is presently very rich, see recommendation by SWC. c. Planting pits are to be backfilled with native soils. Either the entire planting area should be amended with compost or equal or the soil amendments should be placed on the surface around each plant after planting. Studies have shown that survival is reduced if planting pits are backflled with amended soil. Only when there is insufficient native soil (i.e. too many rocks), should topsoil or compost be used for backfilling. d. Root balls of potted and B &B plants must be loosened and pruned as necessary to ensure there are no encircling roots prior to planting. At least the top half of burlap and any wire straps are to be removed from B &B plants prior to planting. e. Where there are existing tree roots, incorporate soil amendments by hand. • See Sensitive area mitigation plan and notes by SWC for recommendation of soil treatment. 4. Existing trees should be shown on the plan. • The site survey has existing trees >8 ". See WT -1 for existing trees. We have also field measured other trees and show them on the planting plan. 5. Specify how non- native vegetation will be cleared (no herbicides will be allowed) and whether Reed Canary grass will be removed from the existing wetland. • As Described the present swale will be cut to remove vegetation and new soils will be added. • The general ground cover of Ivy and blackberry will be removed without herbacides. 6. The wetland sign needs to specifically say to contact the City of Tukwila at 206 -431 -3670. • When wetland is complete a small sign will be added to the site. 7. The Tree Planting Detail doesn't make sense. What does the "18 inch minimum and 6 inch" notes (along the left side of the root ball) refer to? • SWC response; 6" refers to added soil under and 18" has been reduced to 12" around root ball. 8. Where will wetland seed mix be planted — the entire wetland or only the created wetland area? It is not clear whether the existing wetland will be enhanced. • See updated WT -1 planting plan for planting in wetland clarification. 9. Clarify the symbology used and include it in the legend (or remove the map graphic altogether and convey this info on another sheet). • See updated WT -1 planting plan. P.3 Cooke Creek •adows Submittal Wetland a•Buffer Reduction 10. Add a note on this sheet or on W -4 that states that "Evergreen trees shall be a minimum of 6 feet in height at time of planting. Deciduous trees shall have at least a 2 inch caliper at time of planting, determined according to the American Standard for Nursery Stock. Shrubs shall be at least 18 inches in height at time of planting." • SWC response: See new sheet W -1. Mitigation Concept and Goals, Sheet W -4 1. Provide more details on the environmental goals and objectives that describe the purposes of the mitigation measures and the goal for improving wetland and buffer functions. This should include a description of the site selection criteria, identification of target evaluation species, and resource functions (TMC 18.45.090 F2). Is the idea to enhance wildlife habitat, improve water quality, improve hydrology , etc.? Clarify whether the existing wetland will be enhanced along with the buffer. If it is not enhanced, how do you propose to keep Reed Canarygrass out of the new wetland area? How many cubic feet of excavation in the existing wetland and the new wetland are proposed? Include in the discussion that the buffer for Southgate Creek is also being enhanced as mitigation for unauthorized tree clearing within the buffer. • A comprehensive improvement of the wetland and the Creek Buffer will improve the hydrology and natural pollutant removal in the area. I would like to add a path to keep people off the sensitive area enhancement and to provide maintenance capabilities to the area. I would like to comment that we did not remove any trees within 100' of the creek. We do plan to remove most of the ivy in the buffer area and upgrade the planting to enhance the South Gate creek buffer. See the Sensitive area mitigation grading plan for quantities. 2. Provide performance standards of the specific criteria for fulfilling the environmental goals and for beginning remedial action or contingency measures. They may include water quality standards, species richness and diversity targets, habitat diversity indices, or other ecological, geological, or hydrological criteria (TMC 18.45.090 F3). • SWC response; Please refer to new sheet W -1. 3. Detail the monitoring and evaluation program that outlines the approach for assessing a completed project. An outline shall be included that spells out how the monitoring data will be evaluated by agencies that are tracking the mitigation project's progress (TMC 18.45.090F5). Include a contingency plan of actions to take if the project's performance standards are not met (TMC 18.45.090 F6). Regarding Section 5. Monitoring shall be done twice a year, and reported in a once a year monitoring report. Specify who prepares the report. A hydrology performance standard should be included for both the new wetland area and the existing wetland area (given that excavation and a weir are proposed to increase ponding). • See SWC Planting Plan W -1 • Attached is Geo NW analysis of the hydrology for the site. 4. The Director will require a performance and maintenance security guarantee (bond or cash assignment); the guarantee may be held longer than 5 years if the performance standards have not been met or the mitigation has not been successfully established (TMC 18.45.090F7 and 18.45.210). • Where and how do I get this bond or how much cash assignment 5. Sections 1.1 and 2.9. Monitoring will be required for 5 years. • Since the City is the environmental steward and receiving taxes from this new development I believe your environmentalist should monitor it to make suggestions as to what needs to be done. I will drop this statement but after a while one just want to add an opinion or two. 6. Section 2. Include the wetland excavation, construction of bridge and weir in the construction sequencing. • We will modify this section to include more detailed construction sequencing. See WT -1 7. Section 2.7 Prior to final planning approval, the contractor, owner, or landscape architect will sign a City of Tukwila Landscape Declaration. • This is acceptable. 8. Section 3.1.3. End the first sentence at the word "varieties ". Site preparation shall include grubbing out of blackberries but the reference to 4.1.3 is for maintenance and involves cutting back and poison which is not acceptable for site preparation. • Please clarify. We need to get a more common approach to this problem. 9. Section 3.2.1. Add a note stating that container grown plants must not be root bound. • SWC response: Please see revised Notes to Mitigation Plan W -1. P.4 Cooke Creek ladows Submittal Wetland a•Buffer Reduction 10. Section 3.2.5: Add to the note that the City of Tukwila DCD will also need to approve species substitutions or plant sizes. • I would prefer than asking for a substitution that we provide a plan list of acceptable species substitutions that will be acceptable. KLLA to provide the plan 11. Section 3.3.6. Add a note stating that roots are to be loosened prior to planting. • SWC response: Please see revised Notes to Mitigation Plan W -1. 12. Section 4.1.2. Add under work to be included in each site visit: manual weeding around all installed plants. • SWC response: Please see revised Notes to Mitigation Plan W -1. 13. Section 4.1.3. No herbicides allowed without written permission from the City, and if allowed, must be an herbicide approved for aquatic use (not Roundup). • SWC response: Please see revised Notes to Mitigation Plan W -1. 14. Section 4.2. Maintenance shall be done at least twice a year. • SWC response: Please see revised Notes to Mitigation Plan W -1. • Will write this into the CCR for Association to pay. 15. Section 4.3. Change wording to state that watering/irrigation is required during dry periods, no matter when they are planted, and must continue for 3 summer seasons. Include an irrigation plan with the plan set. • Presently there is a water line to the wetland. We plan to use above ground PVC pipe, hoses and above ground sprinklers which will be activated by a battery powered controller. • Irrigation Plan is address in the wetland design WT -1. P.5 Cooke Creek •adows Submittal Wetland aiBuffer Reduction SEPA REVIEW — E09 -001 1. No other permits can be issued before the SEPA determination is issued and the appeal period is exhausted. 2. The traffic concurrency test fee needs to be paid before a SEPA determination can be issued. • Traffic Concurrence fee will be submitted with our package. TREE CLEARING PERMIT —L08 -065 1 This is being reviewed and incorporated into L09 -012. 2. The mitigation plan provided needs to include the stream buffer and the wetland buffer. • We have a wetland and stream buffer plan • How many tree of significance were removed from the stream buffer, NON? FYI • This area has been under utilized for many years we would like to clean it up by removing debris (tires, plastic, garbage, steel), remove ivy and blackberry, add a path, and a few shrubs to the creek buffer. The soil in this area is mostly clay and the tree canopy is conducive to very few plants. This is the principle reason ivy and blackberry does well. 3. The mitigation plan needs to show the trees removed and the tree replacement schedule on a table per TMC 18.54.130 3b as detailed on page 2 of a letter to Todd Smith from the City of Tukwila. • This request is unacceptable and unrealistic. The trees are gone I am proposing adding more than the 16 trees requested by the City that should be sufficient. • Let talk and clarify your concerns. 4. Additionally, in the Adolphson Conceptual Mitigation Plan, page 3 states that as compensation for reducing the buffer to 25 feet, "the remaining wetland and stream buffer areas between the development and the wetland and between the wetland and the stream will be enhanced. In addition, the onsite wetland area will be enhanced to compensate for minor impacts from the pedestrian bridge and pathway located in the buffer and wetland areas." • So, what is your point? The basis for enhancement as per the wetland code is removing invasive species. We have said we would do this. The soil near the creek is mostly clay not conducive to planting much of anything. Level 1 Downstream Analysis 1. Page 2 states that the area is not located in a Landslide Hazard Area. The City has Class 2 areas mapped on about 50 %of the site. Clarify the Blueline report and discuss if there are any resultant changes in the report. • Blueline's comment, see revised Downstream Analysis. 3. Page 3 states that Wetland A is labeled on the Existing Conditions Exhibit (sheet 1.1). It is not. On the Existing Conditions Exhibit, 2 wetlands are shown but one has been determined to not be a wetland. • Blueline's comment, see revised Downstream Analysis. 4. Page 3 states that Sub -basin C is "comprised of undisturbed forest with heavy underbrush" and will "remain undisturbed in the developed condition." Neither of these statements is correct. Page 4 continues with this assertion. Discuss. • Blueline's comment, see revised Downstream Analysis. P.6 ■ �- r-- SP 2 COMMUNI i Y DEVELOPMENT Cooke Creek Meadows City of Tukwila, Washington Level 1 Downstream Analysis Prepared for Cooke Riverside Properties, LLC PO Box 97193 Tacoma, WA 98497 Original Date: March 30, 2009 Revision Date: September 21, 2009 Blueline Job No. 08 -068 Prepared by: Ben T. Rutkowski, PE Reviewed by: Ken M. Lauzen, PE B L U E L 1 N E LAND DEVELOPMENT CENTRAL WAY SI 1 E0400� KIRKLAND WA 98033 • TEL 425 - 216-4051 FAX 425-216-4052 • THEBLUELINEGROUP.COM • • Cooke Creek Meadows City of Tukwila, Washington Level 1 Downstream Analysis Prepared for Cooke Riverside Properties, LLC PO Box 97193 Tacoma, WA 98497 Original Date: March 30, 2009 Revision Date: September 21, 2009 Blueline Job No. 08 -068 Prepared by: Ben T. Rutkowski, PE Reviewed by: Ken M. Lauzen, PE BL U E L 1 N E 25 LAND CENTRAL WAY' SUITE 400 KIRKLAND WA 98033 • TEL 425 - 216-4051 FAX 425 - 216 -4052 ■ THEBLUELINEGROUP.COM • • Cooke (reek Meadows Level 1 Downstream Analysis Table of Contents Task 1: Study Area Definition and Maps 1 Task 2: Resource Review 2 Task 3: Field Inspection 3 Onsite Basin 3 Upstream Basin 3 Task 4: Drainage System Description 4 Sub -Basin A 4 Sub -Basin B 4 Task 5: Mitigation of Existing or Potential Problems 6 Appendix • Downstream Photos • Existing Conditions Exhibit • Developed Conditions Exhibit • Downstream Drainage Exhibit • Geotechnical Engineering Study dated July 17, 2008 and prepared by GEO Group Northwest, Inc. • King County iMAP - Sensitive Areas Legend • Letter addressed to Jim Morrow dated September 15, 2008 describing the flooding problems on the NorMed site. Also included is the City of Tukwila's response. • King County Districts and Development Conditions Report Job # 08 -068 Cooke Creek Meadows Level 1 Downstream Analysis Task 1: Study Area Definition and Maps The project is comprised of two parcels (7340600982 and 7340600983) which total approximately 1.13 acres. The project is located at 13325 MacAdam Road S, Tukwila, Washington. More generally, the site is located in Section 15, Township 23 N, Range 4 E, W.M. Please see the vicinity map below. S 141ST ST 5 142N0 $T Vicinity Map Not to Scale In the existing condition, there is a single - family residence along with various outbuildings. Access to the site is from MacAdam Road S. A site visit was conducted on Thursday, January 8, 2009 to determine the existing site conditions as well as the upstream and downstream drainage basins. Detailed descriptions of the existing site conditions are provided in Task 3 of this report. Detailed descriptions of the downstream drainage basin are provided in Task 4 of this report. In the proposed conditions all onsite structures will be removed. Nine single - family cottage units along with associated infrastructure will be constructed. Please see the Developed Conditions Exhibit included in the Appendix. Job # 08 -068 Page 1 • • Cooke Creek Meadows Level 1 Downstream Analysis Task 2: Resource Review The best available resource information was reviewed for existing or potential problems. The following is a summary of the findings from the information used in preparing this report (see the Appendix for exhibits). • The Geotechnical Engineering Study prepared by GEO Group Northwest, Inc. states: According to the area geologic map, the project site soils are mapped as Younger Gravel (Qyg), consisting chiefly of sand and pebble gravel. However, the site soils encountered consisted of topsoil, silt, glacial till, and glacially consolidated silt. Younger gravel was not encountered. • There is a wetland located on the western portion of the site. Please see the Cooke Property Revised Wetland Delineation Report included in the Appendix. • The site is located in the Duwamish River drainage basin. • The site does not contain any streams. However, the western boundary of the property abuts Southgate Creek. • According to the King County Districts and Development Conditions Report for parcels 7340600982 and 7340600983 (included in the Appendix): o The site is not located within a 100 -year floodplain. o The site is not located in an Erosion Hazard Area. o The site is not located in a Landslide Hazard Area. However, City of Tukwila staff has indicated that Class 2 areas are mapped on portions of the site. o The site is not located in a Seismic Hazard Area. o The site is not located in a Coal Mine Hazard Area. • There are no known relevant drainage complaints on record with King County. However, City of Tukwila staff has identified a downstream flooding problem at the NorMed site. A detailed description of the flooding problem is included in Task 5 of this report. Job # 08 -068 Page 2 • • Cooke Creek Meadows Level 1 Downstream Analysis Task 3: Field Inspection A site visit was conducted on Thursday, January 8, 2009 on a clear and sunny day. There had been heavy rainfall the previous two days. Please reference the Existing Conditions Exhibit included in the Appendix for the Onsite and Upstream Basin descriptions. ONSITE BASIN The project site consists of two parcels (7340600982 and 7340600983) totaling approximately 1.13 acres. The site is split up into three drainage sub - basins. Sub -basin A is located near the eastern boundary of the site and is approximately 0.27 acres. The existing single - family residence is located almost entirely within sub -basin A. The ground cover is comprised of lawn, gravel driveway, trees, shrubs and blackberry vines. The existing topography generally slopes from southwest to northeast with grades ranging from 1 % -20 %. Onsite runoff from this sub -basin sheet flows to MacAdam Road S located along the eastern boundary of the site. Sub -basin B totals approximately 0.74 acres. The ground cover is comprised of lawn /pasture, gravel driveway, trees, shrubs, and blackberry vines. A wetland is also located within sub - basin B and is labeled as Wetland A on the Existing Conditions Exhibit. Runoff from within Sub -Basin B sheet flows to the onsite wetland. The existing topography generally slopes toward the wetland with slopes ranging from 2 % -25 %. Wetland A extends offsite to the north and conveys the runoff onto the adjacent property. Sub -basin C totals approximately 0.13 acres. The ground cover is comprised of forest and pasture. This sub -basin is completely within the Southgate Creek buffer. All runoff from sub - basin C sheet flows west toward Southgate Creek. In the developed condition, there will be no additional impervious area added within sub -basin C. The proposed development will not increase the amount of stormwater runoff to this basin; therefore the immediate downstream drainage course from sub -basin C is not investigated in this report. UPSTREAM BASIN Approximately 0.41 acres of offsite area along the southern boundary are tributary to the site. See the Existing Conditions Exhibit located in the Appendix of this report. Of this area, approximately 0.19 acres are tributary to Sub -Basin A and 0.22 acres are tributary to Sub - Basin B. The ground cover of this area is similar to that of Sub - Basin's A and B. Job # 08 -068 Page 3 • • Cooke Creek Meadows Level 1 Downstream Analysis Task 4: Drainage System Description The downstream drainage path was determined for Sub - Basins A and B. The downstream drainage paths for Sub - Basins A and B converge at approximately the 1/4 mile downstream point from the site. Since Sub -Basin C is entirely within the Southgate Creek buffer, this area will remain unchanged and there will be no additional runoff directed toward this sub -basin in the developed condition. Therefore the downstream drainage path of this sub -basin has not been investigated in this report. Please refer to the Downstream Photos included in the Appendix of this report. SUB -BASIN A Onsite runoff from Sub -Basin A sheet flows west to MacAdam Road S. The runoff then flows north along the west -side shoulder of MacAdam Road S (labeled "A ", Figure DS -01) where it eventually enters a catch basin (B) north of the property. The runoff is then conveyed north along MacAdam Road S in a closed conveyance system. The conveyance system then crossed MacAdam Road S to the east, then north down a steep embankment (C) where it outfalls to a roadside ditch (D) along the south side of S 133rd Street. The runoff then flows east along S 133rd Street, passing through a 24" driveway culvert (E) to where it is collected by an open grate catch basin (F). The runoff is then conveyed north under S 133rd Street via a closed conveyance system that outfalls on the north side of S 133rd Street (G). The runoff then flows northwest in an open drainage feature to the approximate 1/4 mile downstream point (H). There was no evidence of erosion or overtopping along the downstream drainage path to the 1/4 mile downstream point. The downstream conveyance system appeared to have adequate capacity at the time of investigation. It should also be noted that the site visit and downstream investigation was conducted after days of heavy rainfall which produced flooding in many of the nearby rivers. SUB -BASIN B Onsite runoff from Sub -Basin B sheet flows to Wetland A, located onsite. At the time of the site investigation, there was a defined drainage channel flowing from south to north through Wetland A (I). The drainage channel continues north across the adjacent properties to S Job # 08 -068 Page 4 • • Cooke Creek Meadows Level 1 Downstream Analysis 133rd Street. Once the flow reaches S 133rd Street, it is conveyed via culvert to a catch basin located in the flowline along the south side of S 133rd Street (J). The closed conveyance system crosses to the north side of S 133rd Street and outfalls to a defined drainage feature (K). This drainage feature continues north through private property to where it joins the downstream drainage path for Sub -Basin A (H), 1/4 mile downstream from the site. There was no evidence of erosion or overtopping along the downstream drainage path to the 1/4 mile downstream point. The downstream conveyance system appeared to have adequate capacity at the time of investigation. It should also be noted that the site visit and downstream investigation was conducted after days of heavy rainfall which produced flooding in many of the nearby rivers. Job # 08 -068 11, Page 5 • 1 Cooke (reek Meadows Level 1 Downstream Analysis Task 5: Mitigation of Existing or Potential Problems There are no known downstream problems or drainage complaints located within the 1/4 mile downstream drainage path of the site. There was also no evidence of erosion or inadequate capacity along the 1/4 mile downstream drainage course. The downstream conveyance system appears to have adequate capacity to convey the site runoff in the developed conditions. The temporary erosion and sedimentation control plan will be designed to reduce the discharge of sediment -laden runoff from the site. The plan . is comprised of temporary measures (rock entrance, filter fence, straw mulch, etc.) as well as permanent measures (hydroseeding and landscaping). All TESC facilities will be periodically inspected and maintained as necessary during construction to minimize impacts to the downstream system. City of Tukwila staff has identified a downstream flooding problem on the NorMed site. During periods of high rainfall, the onsite stream overtops and floods the NorMed site. This stream is part of the downstream drainage path for the site, but it is past the 1/4-mile downstream point. It has been determined by the City of Tukwila that proper maintenance by the NorMed property owner should alleviate the current flooding issues. A copy of the letter written to the City of Tukwila detailing the flooding issue as well as the City's response has been included in the Appendix of this report. Job # 08 -068 Page 6 • • Cooke Creek Meadows Level 1 Downstream Analysis Appendix Job # 08 -068 Page 7 Cooke Creek Meadows Level 1 Downstream Analysis Downstream Photos Onsite photo looking from the high -point of Sub -Basin A/B toward MacAdam Road S. Frontage along MacAdam Road S, looking north. Job # 08 -068 Page 8 • Cooke Creek Meadows Level 1 Downstream Analysis • lenieht;;;M•.1• k . A tlif Witirt4e2.• ..._...._,._ , ., .9 --A. 111111111---- I •c--F.:-.;2.:11.11-',1141.11.1., Discharge to open ditch along S 133rd Street (D). Open drainage course along the south side of S 133rd Street. Job # 08-068 Page 9 • • Cooke Creek Meadows Level 1 Downstream Analysis Open grate catch basin along S 133rd Street (F). Onsite Wetland A, looking north onto adjacent property. Job # 08 -068 Page 10 Sep 27, 2009 — 174.5p,, — User bretkowsel \Proprels\08058\0.9\514bles\Level 1 0owns7reern\080613 EC—LEVI.dep I• envrror", IF .1 !SLAP I I I.-- i 1 --- ':=_',.., y'rn, ,..*7`■ • ..:::—:-. -----. , — 1 :" :-Cr _ EXISTING CONDITIONS EXHIBIT ' • _ • -- 1 - - Y2I • ' . " • / ' UB-BASN C 8 \ \t 1 up 0 1 - Civ.---- 1'1' ---- _--- ------ 46."------ ---- ---- ---- --- ---- 43RD AVE BJ %.4-, s• ' ... . S r.■t.,:4•:r.:•:.'" -,.. • Q ' JOB NUMBER: 08-068 SCALE AS NOTED COOKE CREEK MEADOWS EXISTING CONDITIONS EXHIBIT LEVEL 1 DOWNSTREAM ANALYSIS 0 2008 7NE BLUELINE GROUP It11$ BLUELINE PROJECT MANAGER KEN M. LAUZEN, PE DESIGNED BY BEN T. RUTKOWSKI. PE DRAWN BY BEN T. RUTKOWSKI, PE DATE 9/21/09 I• envrror", IF .1 !SLAP I 1 Nor 25. 2009 — 11: JSOm — Usor Dou9nea E \Pmpeb \09099 \Dry \EthAlh \Level 1 Downafeonr \09 —G68 0501.owp 4DTH AVE S En 00 SCALE 1' =150' PROJECT MANAGER KEN M. LAUZEN, PE DESIGNED BY BEN RUTKOWSKI. P£ DRAM BY VAN HUGHES DALE MARCH 25 T11Q9 DOWNSTREAM DRAINAGE EXHIBIT CREEKSIDE COTTAGES LEVEL 1 DOWNSTREAM ANALYSIS �© 2008 THE BLUEUNE GROUP (11 ••\•kt1 Z m • GEOTECHNICAL ENGINEERING STUDY COOKE CREEK MEADOWS PROPOSED COTTAGE HOUSE DEVELOPMENT 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON GGNW Project No. G -2742 Prepared for Mr. Todd Smith Cooke Riverside Properties, LLC PO Box 97193 Tacoma, WA 98497 July 17, 2008 Prepared By GEO Group Northwest, Inc. 13240 N.E. 20th Street, Suite 10 Bellevue, WA 98005 Phone: (425)649 -8757 • V\ civo °\\%L-We^SVY )0.105)3 INFILTRATION EVALUATION COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON GGNI Project No. G -2742 Prepared for Mr. Todd Smith Cooke Riverside Properties, LLC c/o Mr. Chandler Stever Chandler Stever Architect 1715 - 223rd PI NE Sammamish, WA 98074 August 11, 2009 Prepared By GEO Group Northwest, Inc. 13240 N.E. 20th Street, Suite 10 Bellevue, WA 98005 Phone: (425)649 -8757 2009 DEOELOuMENY • • Group Northwest, Inc. Geotechnical Engineers, Geologists & Environmental Scientists August 11, 2009 Mr. Todd Smith Cooke Riverside Properties, LLC c/o Mr. Chandler Stever Chandler Stever Architect 1715 - 223rd PI NE Sammamish, WA 98074 Subject: Infiltration Evaluation Cooke Creek Meadows 13325 Macdam Road South Tukwila, WA Ref: GGNW Project No. G -2742 Report titled, "Geotechnical Engineering Study, Cooke Creek Meadows, Proposed Cottage House Development, 13325 MacAcam Road South, Tukwila, Washington," dated July 17, 2008, by GEO Group Northwest, Inc. Dear Mr. Smith and Mr. Stever: Soil samples were collected from three hand auger borings to estimate the soil infiltration rate in the areas of the proposed rain gardens and proposed expanded wetland. The location of the hand auger borings are illustrated on the Site Plan, Plate 1. One soil sample from each boring was analyzed for grain size distribution by ASTM Test Method D422, and included hydrometer analysis for silt and clay percentages. Two of the samples analyzed were collected from the proposed wetland expansion area and one sample from the rain - garden area (near proposed rain - garden #5). Soil infiltration rates were estimated based on the Unified Soil Classification System (USCS) method and the United States Department of Agriculture (USDA) textural method, in accordance with the Department of Ecology manual (I)• Washington State Department of Ecology, 2005 Stormwater Management Manual for Western Washington: Volume III -- Hydrologic Analysis and Flow Control Design/BMPs, February 2005, Publication No. 05- 10 -31, Chapter 3.3.6. 13240 NE 20th Street, Suite 10 • Bellevue, Washington 98005 Phone 425/649 -8757 • Fax 425/649 -8758 • • August 11, 2009 Cooke Creek Meadows Soil Infiltration Evaluation G -2742 Page 2 WETLAND EXPANSION AREA Soils analyzed from the wetland expansion area were collected from a depth of 3 feet to 3.5 feet below the existing ground surface, just below the bottom of the proposed cut to create additional wetland detention. Boring HA -A was located about 13 feet south of the proposed weir and Boring HA -B was located about 50 feet south of the proposed weir, approximately as indicated on the Site Plan, Plate 1 of Illustrations. Soil Classification The following are the USCS and USDA soil classifications for the wetland soils, based on the Particle Size Distribution Reports, Plates B 1 & B2 in Appendix B and Plates C2 & C4 in Appendix C: USCS Soil Classification: Clayey SILT with some sand and a trace of fine gravel USCS (D10): HA -A = 0.0015 mm; HA -B = 0.0097 mm USDA Textural Classification: Silt Loam Estimated Design Infiltration Rate The fine grained Clayey Silt / Silt Loam in the wetland expansion area, at a depth of 3 to 3.5 feet, is not permeable and has no design hydraulic capacity based on both the USCS and USDA methods for estimating infiltration rates. Under the USCS method, an infiltration rate is not available for soils with a D10 of less than 0.05 mm (soil particle size at the 10 percent passing point on the grain size analysis curve) and the wetland soil has a D10 of 0.0097 mm or less. With the USDA method, Silt Loam is not considered to have infiltration capability. Considerations Water entering the wetland area currently flows northerly following an existing ditch line. Based on the soil analysis the water is sheet flowing on top of the relatively impermeable soils with minimal infiltration. We understand the proposed site development will include increasing the wetland capacity to retain water during storm events. By excavating and creating a depression, water will pond and can then be released at a controlled rate with a weir system. The existing GEO Group Northwest, Inc. August 11, 2009 Cooke Creek Meadows Soil Infiltration Evaluation G -2742 Page 3 wetland soils at 3 to 3.5 feet should not be considered capable of absorbing and storing water. If an increase in the hydraulic capacity of the wetland soils is needed, it may be possible to amend the existing soil by adding sand. The sand content of the existing soil ranges from 13 to 24 percent, based on the two soil samples analyzed and based on the USDA textural classification system. At a minimum the sand content should be increased to 60 percent which would change the soil classification to a Sandy Loam which has some capacity to infiltrate. Increasing the sand content would require removal of a portion of the site soil and replacement with imported sand that is tilled into the soil. Alternatively, the site soil could be removed and replaced with an appropriate imported sand mixture designed to achieve the hydraulic capacity and infiltration rate engineering requirements. RAIN GARDEN AREA The soil analyzed for rain garden evaluation was collected at a depth of 2 feet to 2.5 feet below the existing ground surface in the area where rain garden #5 is proposed. For the purpose of this evaluation the soil sample is considered to be generally representative of the on -site soil. Soil Classification The following are the USCS and USDA soil classifications for the soil sample analyzed near Rain Garden #5 and are based on the Particle Size Distribution Reports, Plates B3 in Appendix B and Plates C5 in Appendix C: USCS Soil Classification: Silty SAND with gravel, some clay, and occasional cobbles. The sand is predominately fine grained. USCS (D10): 0.0062 mm USDA Textural Classification: Sandy Loam Estimated Design Infiltration Rate The rain garden soil evaluated has a estimated long -term design infiltration rate of 0.25 inches per hour (estimated short term infiltration rate of 1 -inch per hour with a correction factor of 4), based on the soils Sandy Loam USDA textural classification (Table 3.7, Page 3 -76 of the Ecology Manual'). Under the USCS method, the D10 of the soil is less than 0.05 mm and an GEO Group Northwest, Inc. August 11, 2009 Cooke Creek Meadows Soil Infiltration Evaluation G -2742 Page 4 estimated design infiltration rate is not available. Considerations Soil Variability: Based on the grading plan some rain gardens will be built up with fill soil. Some of the fill may be generated during excavation to construct the building structures. Based on the project geotechnical engineering study, most of the site soils were logged in the field as consisting of silt with variable amounts of sand and gravel. It is recommended that soil to be placed as fill in the rain garden areas be evaluated at the time of excavation if infiltration is required. Sandy soils should be segregated at the time of excavation, stockpiled separately, and analyzed for grain size distribution to determine the sand/silt/clay percentages in order to determine if the soil will infiltrate. Till: The site is underlain by relatively impermeable glacial till soils. Water infiltrating into the ground will ultimately sheet flow down - gradient on top of the underlying till. Building foundations and basement walls should be protected from potential intrusion of water seepage. The use of waterproofing, installation of drain mats on the exterior of basement walls, and installation of footing drains around foundation perimeters, is recommended as discussed in the Basement wall Drainage and Drainage Sections of the referenced project geotechnical engineering study. Long -Term System Viability: The design of the rain garden system should include measures to mitigate clogging of the fine grained soils in order to maintain the long -term operational viability of the system. The measures should include wrapping drain rock in infiltration trenches and footing drains with geotextile filter fabric, such as Mirafi 140N or equal, as well as the screening and filtering inlet water into the infiltration trenches. infiltration Laterals: Lateral infiltration drains may be incorporated into the design of the rain gardens to increase the infiltration capability of the system and provide water to planting areas. The laterals can be designed as an infiltration trench, in general accordance with the Infiltration Trench Detail, Plate 2 of Illustrations. Trenches should be constructed level to maximize infiltration and designed to prevent or collect overflow. - GEO Group Northwest, Inc. • August 11, 2009 Cooke Creek Meadows Soil Infiltration Evaluation • G -2742 Page 5 Please call if you have any questions. Sincerely, GEO GROUP NOR _ WEST, INC. zvg.a Wade Lassey Engineering Geologist William Chang, P. E. Principal Attachments: Illustrations: Plate 1 - Plate 2 - Appendix A: Hand Plate Al - Plate A2 - Plate A3 - Plate A4 - Appendix B: USCS Plates B1 - Plates B2 - Plates B3 - Site Plan Infiltration Trench Detail Auger Boring Logs USCS Legend Boring Log HA -A Boring Log HA -B Boring Log HA -C Grain Size Distribution Boring HA -A, Soil Sample at 3 - 3.5 feet Boring HA -B, Soil Sample at 3 - 3.5 feet Boring HA -C, Soil Sample at 2 - 2.5 feet Appendix C: USDA Plate Cl - Plate C2 - Plate C3 - Plate C4 - Grain Size Distribution USDA Textural Triangle Boring HA -A, Soil Sample at 3 - 3.5 feet Boring HA -B, Soil Sample at 3 - 3.5 feet Boring HA -C, Soil Sample at 2 - 2.5 feet GEO Group Northwest, Inc. . ILLUSTRATIONS GEO Group Northwest, Inc. • LEGEND HAND AUGER BORING NUMBER AND APPROXIMATE LOCATION +HA-A • NE 7.'4. SEC 7 S. TWP 23 N , RGE 4E. W.M. CG",' 0') rlYWOO •„. N REDUCED SCALE 1" = -10* / ; e HA-BP' STANDARD CONSTRUCTION NOTES Row ro smarm ccosowcw• oa•T•cr adr-fOn (7-.01-.00- 07. SW ...or .000WO 0211600 Water woosto, rffs ^COW IWWIle morwe OW CO-WO "CO were /037 SOW COW Off -Off • WOOD. WON P. MAO WWLS WP1323.4 7 A r MASI . Won LOW STARING 100.1•Cr 33 OW. O.• won's •• 303.7 hAuC 363 gown off•SCroal •I tew: W.175 Wsworf fa WYK Off 7. CONIRACIpe Avows arsx 114-017•01110, roe 40,0■11: SOW.. NO WOOIDOOS /OM eaCo CrortOWnof CROMOYS Yr COOLOW7C0 Owl RAW W Orloa0s).00 Cowan. 71C ARM0007 Al..1 .0 • Cu.., COW Os ors Or TRW, oncla•Wor adoewscr off WSOP COODOW. SWOOPS AVOW. O Pr If SOL Att Oar WO MOW+ re 7orff Rows. OOD/33 War 0.10SW MAO 333813 fOrwrIrowl OW Po oaf, no ...AWL ARO w Orr O WOW r ALL WO■00.1 00 •orMAL.5 Sawa oar or/ La Wel, 011•10/.1, OROCIARS Oa OW. C.03.700 MAW= worn olWRIol OTRouro RV OE MAK qffS LWOW LOWWCW Wow Wow. A CLOW Mr Or RECCoo WORMS 0/4.93. 7 0.7wwws ow" raw. *WOW WAN.. MOW NOWCT n3.4 WOO., IWO. CO.Off COMM ANS ORM ownpllOCr lar WOLK WO, ...OW 37.3 artworrAOLM I. ALI SOMOVO ra• MOM !AMORY SOW Or VOW WOW SOO MILTON or A PS.O7. 00013777 3.337.1. 31303 ow sow( CR" sow mu NORT7Orro wn112 WWI ff ,ot,MarroyrAIrgrO)070•111.4.1 voRIN TOW aWsc so0 04" WOO' crr:01 nOCff CO.. SOO. IRE DOW= SOU OVA. CDOODO. .10.11.03.3 /a MOO MO a /OWL . /31.0.4 All SO 6 ow.. DPP wow. ClOr TO CONSIWCIWA 1 S;t7,1 Wow, Ca WSW, OlaWO WISL003 901117-Ce- wy. (.4.4(1AWIJ, .0 KOMI :101.410fflat • Oale eamayste smu. PEWS .0 W003.34 aa• MOO-33 SLOG• I ow - -74`2P.4! 3 ADP to/ moinolO •7 Or of WOO WA. 41 yr. WC, WORT, 33.Pha Of.. POP lasOLW .0 All.WW1 • 44 WO ■ o Row.. ra woo &WI OIC o Ws no ressiWow con.3. FOO/OWS .../0 DO7/.0 ar.arl -3, mo . eASINPOS nos wowc .1•3a ...Pr a Yew, ,,,o,..' ..Zrr. • LIIT ...: .-::1,7 Yr. IR( 1.{... „I.T117,...,. ,Lys....4. a:en:to:HI Orr • POW.. Pr ...Or( WU lift:OW. 1 a ne. COMORO 5 • 0 MCC: •I 34 ra3 /3 . 3.5./...r . . KW, 33/3/73. .03 Pra /WOWS WI ILALIC u•C WRAIr .OW.0 WIWI lot tO. DM Offarir AV 0C4-00.1 Or MOW Sul. %NS. Yr Ws off .o WoOLCADOS Csuo20 Or AC :016:71,t 0.417.406:1 lAgill WI: WI. •I(01•1031rxii :". Alt 0::. 41M4:AV :AY LIOVOLS WS( SC ll." TIN? (44.1, .:401. Pr 1.033 //,93.•.w. /3 KftalOr POI Woe, rOR WI Woks Oh Mr roopoo owww. o *sr :claw. wows 21. sse osalC7COWLS wl ...a.W WO 101..01, al Pr lao. 0/1.3 ay. 4 ...Ors yr "Mae mr.r1 /1/3.334/ •Aes, . ...as raishOo wrow•Co Or ESC a On...73131713:41.....=.01.... OC1 SS roll:00 SAW.. •1•00.00 Ar Iltdati 7 OIL. Pf1.17,00 o WOW WOR Ni W. OW, OCIARnow woe To ealro. Of aelst ....ass ' VniT = Perril,7--27ZtaTsra,===fiVol.".ITTZVor '' ^ ...012.: AU 040 00....Cr ma.. 7rOW .Ir• OWL. MORI Ownro. 047.01 - ...o 0.ry :A.:7y, . CilorOlf a no 7:4- 2'00 4,44, , ..I. SIM 140, 010,I ANY 12:1001. •I oder 444. onr , 5•004(0 ... ":4: 72AJ: .1' 3 /V.. oa OUR... Ilera.. Ow., I•C Oa.. 1.7•0.70 ow, roywo /177 Ow ,Corar.. r osPeCr ACCINOW r0 AR WOW. OC wycoot scoff., .0 yor •RISTO ffRoses -00or AO, .0.00. O..01.3323 p. go ow./ Or/COW .0 Craw. CLOW, ROO WW1.. ao at .....13 fLIPPI Aff W.iLLYLS1 wow arajoawr3 • 110.1r arandOC AP, COWIWCOON iS7A0L02: ci.L.000 013.11 OPSHOW. (.474.404 4:0 geS14:1 V.V. AWAY!. .0 .044::: .:0411411 at A.A.. ▪ WOW .1, dc4.4. DaWaoaar DC.31 /Kt 00106WAIR (ROO. WV-wan .0 Slaw. A=orefOrALVICVARA:rWrL7WAr AAA A'A A C./7101. KO.. ?SO +WI Criblinde ./40 sr 33.../03 AISSALE APO ALL Lir kr WRVS AMMO. I1 I Mr r3C 40A/S: ALL MIMI*. CA. 11•51,15 +.443 o PRIM RO•11-0,407 OSIWAOS OMR Wow, AatOff CSC WOW. OIL.. 104.1-21: (MM. V011 41.1I ItACC :AM 'WA 33 3.6.13.03 WO.. APO RIP.4300 SLOPOLOOP .74//73.13 SEI.L.3313.3,01L.1 •LE MOO/ OrGoartaP unroof. loot off CO IsitIO ..r../.31 ...14.5 :4:4474:9 OW: •-:17: 01:00 ott AGM VIII: srSIVIS WAL• OS, Wys OrOtalt4000•5 1 /Ma RIA7 I ROO. 3.4...31 .0010, ToDOWL VP CO. YEA9.02, WIttor CORO!. off. Rol 13.1 DOOM ..../.0.30 Ica SION Ion Go Ratr s Trod WOOER WOW Wax 33 P./01/10r SpICOOr off wow.. MVO, W... In POMO OSIORSID ARC. MO WI Lbw/ WNW. r. OM. 0 Was .001.1 O0 FP Y.. :6.01WID 17:1 WWI :N. I, rs• iCaaS Orleoftr. sor. C.ra ort0.1.3 r0 COW :al 0•27c.r.r AOKAS IT .33ara • SOO Aga ARWS rWr Prow wow10 CLOW 11.4 or, YAW, Off SCOW wow Row ow war ol DOW WOS 7 rossuff r0 w.d7Aor orASLorl 44.:(.4.(A" ▪ 4(VA: wo ■0:42.4 IMO HIROO. •I •••• OROS,. Or 00 ra3 /DO .335. . • LAW ALAReff nroTRO WOW W. wow, .1 LOCA017. • aLowa LW •••••C.CI. er•Pa/7. SOO 6:4•47.., CCO3 COWDCA■ /DO Ory, y WSW!. OR WIRCe wr WARR offrACCI .00.11 Caw 1/11.113. otraon.. AND Sffsoffsor coos. elf.MACS. 0.0.4 MOM., 2ftKIS. 41:04•044. API*OVID 1442 • 1,1,-.:rr,,tat, 7=r:I = taM.r SOV;r:.;;Lrvra ono reM Wool ro STIO.11 CR•••5 1--Offir1041710-1- I-- • 'Imo SOW i 13' I 7/Tao. .7-Mop SW //loops., SITE PLAN PLATE 1 MACADAM ROAD INFILTRATION TRENCH CAP SOIL 1 - 1 1 4 -INCH PERFORATED PVC RIGID DRAIN PIPE 1 GEOTEXTILE FILTER FABRIC, MIRAFI 140N, OR EQUAL 1 1 1 WASHED GRAVEL NOTES: • I< WIDTH 2 -FEET 1 1 1 1 1 1 1 1 1 1 1 ■ NOT TO SCALE DEPTH 2 -FEET The trench should he lined with geotextile filter fabric, such as Mirafi 140N, and filled with washed rock. The top foot ( + / -) should be capped with top soil. A 4 -inch perforated rigid PVC drain should be laid in the rock. 1 12" The trench should be level to prevent overflow. An outlet tight -line pipe could be installed to capture overflow and return excess water to system. GEO Group Northwest, Inc. Geotechnical Engineers, Geologists, & Environmental Scientists INFILTRATION TRENCH DETAIL COOKE CREEK MEADOWS SCALE NONE DATE 8/11/09 MADE WJL CHKD WC JOB NO. G -2742 I PLATE 2 • • APPENDIX A HAND AUGER BORING LOGS GEO Group Northwest, Inc. LEGEND OF SOIL CLASSIFICATION AND PENETRATION TEST UNIFIED SOIL CLASSIFICATION SYSTEM (USCS) MAJOR DIVISION 1 GROUP SYMBOL TYPICAL DESCRIPTION LABORATORY CLASSIFICATION CRITERIA WELL GRADED GRAVELS, GRAVEL-SAND CLEAN GW I MIXTURE. LITTLE OR NO FINES I POORLY GRADED GRAVELS, AND GRAVEL-SAND MIXTURES LITTLE OR NO FINES GRAVELS GRAVELS (little or no • (More Than Half fines) COARSE- Coarse Grains GRAINED SOILS ' Larger Than No 4 Sieve) DIRTY GRAVELS More Than Hatt by Weight Larger Than No. 200 Sieve • GP (with some fines) GM , SILTY GRAVELS, GRAVEL-SAND-SILT MIXTURES GC CLAYEY GRAVELS, GRAVEL - SAND -CLAY MIXTURES SANDS CLEAN SANDS (More Than Hall Coarse Grains (little or no Smaller Than No. fines) 4 Sieve) I-- DIRTY SANDS (with some fines) _ . SW WELL GRADED SANDS, GRAVELLY SANDS, 1 LITTLE OR NO FINES SP POORLY GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES SM SC SILTY SANDS, SAND -SILT MIXTURES CLAYEY SANDS, SAND -CLAY MIXTURES Cu = (D60 / D10) greater than 4 DEItHMINE Cc = (0302) / (010 060) between 1 and 3 PERCENTAGES OF GRAVEL AND SANG FROM GRAIN SIZE DISTRIBUTION CURVE SILTS Liquid Limn INORGANIC SILTS, ROCK FLOUR, SANDY SILTS (Below A -Line an < 50% ' ML OF SLIGHT PLASTICITY -- Plasticity Chart FINE•GRAINED ; Negligible Liquid Limit INORGANIC SILTS, MICACEOUS OR SOILS Organic) > 50% MH DIATOMACEOUS, FINE SANDY OR SILTY SOIL. CLAYS Liquid Limit CL (Above A -Line on < 30% Plasticity Chart, Negligible Liquid Limit Organic) > SO% CH More Than Hail by. .-... ..-. - -- --- -• - Weight Larger Liquid Limit (ORGANIC SILTS 8 OL Than Na. 200 i < 50% Sieve CLAYS (Below A -Line on Plasticity Chan) > 50% I Liquid L' id L it I OH HIGHLY ORGANIC SOILS INORGANIC CLAYS OF LOW PLASTICITY, GRAVELLY, SANDY. OR SILTY CLAYS. CLEAN CLAYS INORGANIC CLAYS OF HIGH PLASTICITY. FAT CLAYS ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY ORGANIC CLAYS OF HIGH PLASTICITY Pt PEAT AND OTHER HIGHLY ORGANIC SOILS COARSE GRAINED SOILS ARE CLASSIFIED AS FOLLOWS: < 5% Fine Grained: GW, GP, SW, SP NOT MEETING ABOVE REQUIREMENTS ATTERBERG UMITS BELOW 'A" LINE CONTENT OF FINES or P.I. LESS THAN 4 EXCEEDS 12 %I ATTERBERG UMITS ABOVE "A" LINE or P.I. MORE THAN 7 Cu = (060 / 010) greater than 6 Cc = (0302) / (D10. 06.0) between 1 and 3 NOT MEETING ABOVE REQUIREMENTS ATTERBERG LIMITS BELOW > 12% Fine Grained: A' LINE GM, GC, SM, SC CONTENT OF with P.I. LESS THAN 4 FINES 5 to 12% Fine EXCEEDS 12% ATTERBERG OMITS ABOVE Grained: use dual "A" LINE symbols with P.I. MORE THAN 7 60 I I I PLASTICITY CHART FOR SOIL PASSING NO. 40 SIEVE W 40 O - I }301- - U COCO - 20 I A -Line CH or OH —w 10 -- 7 4 0 i I I 4- —I -aMH or OH — l -a.— I � � OL MU { I I 0 10 20 30 40 50 60 70 80 90 100 110 UQUID LIMIT ( %) FRACTION SILT /CLAY SAND FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES BOULDERS ROCK FRAGMENTS ROCK SOIL PARTICLE SIZE U.S. STANDARD SIEVE Passing Retained Sieve (mtm) Sieve I (mm e) 0200 0.075 GENERAL GUIDANCE OF SOIL ENGINEERING PROPERTIES FROM STANDARD PENETRATION TEST (SPT) SANDY SOILS 040 I 0.425 010 I 2.00 04 4.75 0200 040 4110 0.075 0.425 2.00 19 78 04 4.75 19 78 mm to 203 mm Blow Relative Counts Density N I % 0.4 0 -15 4 -10 15 -35 10 -30 35.85 30 - 50 85.85 >50 85.100 Friction Angle di, degree Descnption 28 -30 28 -35 35 -42 38 -46 Very Loose Loose Medium Dense Dense Very Dense SILTY & CLAYEY SOILS Blow Counts N <2 2.4 4 -8 8 -15 15 -30 >30 Unconfined Strength qu, tst .-- < 0.25 Very soft Descnption 0.25 - 0.50 0.50 - 1.00 1.00 - 2.00 2.00 - 4.00 > 4.00 Soft Medium Stiff Stiff Very Stiff Hard >203mm >76mm >0.78 cubic meter in volume GEO Group Northwest, Inc. Geotechnlcal Engineers, Geologists, S Environment al Scientists 13240 NE 20th Street, Suite 12 Phone (425) 849.8757 Bellevue, WA 98005 Fax (425) 849-8758 PLATE Al HAND AUGER BORING NO. HA -A LOGGED BY WJL EXCAVATION DATE 8/3/09 GROUND ELEV. 51 feet (f) DEPTH ft. USCS SOIL DESCRIPTION Sample No. Moisture % COMMENTS _ 2 — 3 — 4 — 5 _ 6 — 7 ML SILT with fine sand, brown, some brick, loose, dry ,— . Clayey SILT, some fine to medium sand, mottled gray, hard, trace gravel, dry to damp IS5 22.0 Probed 0" from surface to bottom of boring - hard. Total Depth = 3.5 feet No Water Seepage Encountered HAND AUGER BORING NO. HA -B LOGGED BY WJL EXCAVATION DATE 8/3/09 GROUND ELEV. XXX feet (±) DEPTH ft. USCS SOIL DESCRIPTION Sample No. Moisture % COMMENTS 1 2 — 3 _ - ML - -_. ML Fine Sandy SILT, trace gravel, dark brown, very stiff to Clayey SILT, some medium to fine sand, mottled gray, trace gravel, hard, damp S3 II.5 S4 22.7 Probed 1/4" at surface to1.5 ft. - hard Probed 0' from ft. to3.5 ft. - hard. 4 — 5 — 6 — 7 Total Depth = 3.5 feet No Water Seepage HAND AUGER BORING LOGS PROPOSED COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON GEO Group Northwest, Inc. vIr Geotechnical Engineers, Geologists, & Environmental Scientists JOB NO. G -2742 I DATE 8/11/09 I PLATE A2 HAND AUGER BORING NO. HA -C LOGGED BY WJL EXCAVATION DATE 8/3/09 GROUND ELEV. 60 feet (±) DEPTH ft. USCS SOIL DESCRIPTION Sample No. Moisture % COMMENTS 1 — 2 — 3 4 _ 5 6 — 7 , � N. ML _ _ SM Fine Sandy SILT, brown, some gravel, very stiff, dry —. Silty Sand with gravel, mottled white, hard, predomently fine to medium grained sand, some clay, chunky, not cemented, dry 1 S1 j S2 10.4 Probed 1/2" at surface - very stiff. Probed 0" from 6" to bottom of boring - hard. Total Depth = 2.5 feet No Water Seepage Encountered HAND AUGER BORING NO. LOGGED BY EXCAVATION DATE GROUND ELEV. feet (±) DEPTH ft. USCS SOIL DESCRIPTION Sample No. Moisture % COMMENTS HAND AUGER BORING LOGS PROPOSED COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON CEO Group Northwest, Inc p wes. _ Geotechnical Engineers, Geologists, & Environmental Scientists JOB NO. G -2742 I DATE 8/11/09 I PLATE A3 - -..... • • APPENDIX B USCS GRAIN SIZE DISTRIBUTION GEO Group Northwest, Inc. USCS HA —A Particle - S C .- - s ti Size Distribution Report s ° 8 100 80 70 re w 60 W LiJ 40 a 30 20 o i l �i 1 I; .r•`_....•_I' 1 —��- 1 'I I I i I i I i ,-�._i • • • , I I I .— ____L- - -_ I I — i r , I, I ; �- I 1; -T -- - - - - -- } I { i l i I i t i I I 500 100 10 1 GRAIN 0.1 0.01 0.001 SIZE - mm % COBBLES % GRAVEL % SAND % FINES CRS. FINE CRS. MEDIUM FINE SILT CLAY 0.0 0.0 1.1 1.1 5.3 5.9 54.2 32.4 SIEVE SIZE PERCENT FINER SPEC.* PERCENT PASS? (X =NO) Material Description Gray clay like soil w/ agg Atterberc Limits 3/4 in. 3/8 in. 1/4 in. #4 #10 #40 #60 #100 #140 #200 #270 100.0 99.1 99.0 98.9 97.8 92.5 90.6 88.0 88.0 86.6 84.2 PL= LL= PI= Coefficients 085= 0.0562 D 0.0145 D 85° 60' = D50= 0.0097 030= 0.0046 D15= 0.0020 D10= Cu= Cc= Classification USCS = AASHTO= Remarks Tested/Calculated by M.Holtz Reviewed by M.Blackwell sampled on 8/3/09, ran on 8/6/09. (no six- :ification provided) Sample No.: 194 Source of Sample: S -5, El 48', 3 -3.5' deep, Tp -A Date: 8/6/09 Location: Elev. /Depth: A.A.R. Testing Laboratory, Inc. Client: Geo Group N.W Project: Cooke Creek Meadows G -2742 Project No: 09 -105 Plate 194 PLATE Bl • USCS • HA —B PERCENT FINER 100 90 Bo 70 80 50 40 30 20 10 0 Particle Size Distribution Report el IN a a 100 GRAIN SIZE - mm 01 0.01 0.001 % COBBLES % GRAVEL % SAND % FINES CRS. FINE CRS. MEDIUM FINE SILT CLAY 0.0 0.0 1.7 1.1 5.3 13.3 54.7 23.9 #10 97.2 #40 91.9 #60 88.3 #100 85.4 #140 82.4 #200 78.6 lI 73.2 j _ f • h. t l ' I' 1 i i I { I 1 I i 100 GRAIN SIZE - mm 01 0.01 0.001 % COBBLES % GRAVEL % SAND % FINES CRS. FINE CRS. MEDIUM FINE SILT CLAY 0.0 0.0 1.7 1.1 5.3 13.3 54.7 23.9 SIEVE SIZE PERCENT FINER SPEC.' PERCENT PASS? (X =NO) 3/4 in. 100.0 3/8 in. 98.7 1/4 in. 98.5 #4 98.3 #10 97.2 #40 91.9 #60 88.3 #100 85.4 #140 82.4 #200 78.6 #270 73.2 (no specification provided) Sample No.: 193 Location: Material Description Gray Clay like soil w/ organics PL= D85= 0.142 D30= 0.0065 Cu= 15.48 USCS= Atterberq Limits LL= PI= Coefficients D60= 0.0232 D15= 0.0031 Cc= 1.21 Classification AASHTO= Remarks Tested /Calculated by M.Holtz Reviewed by M.Blackwell sampled on 8/3/09, ran on 8/6/09. D50= 0.0146 D10= 0.0015 Source of Sample: S -4, El 50', 3 -3.5' deep, HA -B A.A.R. Testing Laboratory, Inc. Date: 8/6/09 Elev. /Depth: Client: Geo Group N.W Project: Cooke Creek Meadows G -2742 Project No: 09 -105 Plate 193 PLATE B2 • USCS HA —C PERCENT FINER 100 90 80 70 60 50 40 30 20 10 0 Particle Size Distribution Report 2 c • • h r g � a 1 1 1 1 I ? % FINES CRS. FINE CRS. — I CLAY 5.5 12.2 9.6 6.6 10.0 I -1-1 7.9 1/4 in. 75.2 I I�{ 72.7 I #10 66.1 . � J • - - - -- i 1 ■ ! j 1 • I = i I � 1 ! ! i – #100 41.3 � ! 13 1 I +1 t 36.8 ! 1 NII' I IL #200 #270 31.2 1 . i I 1 � I i I I i i I :111 ! j � -.) 100 GRAIN SIZE - mm 01 0.01 0.00 1 % COBBLES °A, GRAVEL % SAND % FINES CRS. FINE CRS. MEDIUM FINE SILT CLAY 5.5 12.2 9.6 6.6 10.0 22.2 26.0 7.9 (no specification provided) Sample No.: 195 Location: Material Description Light Brn silty soil w/ agg PL= D85= 26.0 D30= 0.0481 Cu= 102.80 USCS= Atterberg Limits LL= P1= Coefficients D60= 0.641 D15= 0.0095 Cc= 0.58 Classification AASHTO= Remarks Tested/Calculated by M.Holtz Reviewed by M.Blackwell sampled on 8/3/09, ran on 8/6/09. D50= 0.273 D10= 0.0062 Source of Sample: s -2, El 58', 2 -2.5' deep, HA -C Date: 8/6/09 Elev. /Depth: A.A.R. Testing Laboratory, Inc. Client: Geo Group N.W Project: Cooke Creek Meadows G -2742 Project No: 09 -105 Plate 195 PLATE B3 SIEVE SIZE PERCENT FINER SPEC.* PERCENT PASS? (X =NO) 1 1/2 in. 100.0 3/4 in. 82.3 3/8 in. 77.2 1/4 in. 75.2 #4 72.7 #10 66.1 #40 56.1 #60 48.7 #100 41.3 #140 36.8 #200 33.9 #270 31.2 (no specification provided) Sample No.: 195 Location: Material Description Light Brn silty soil w/ agg PL= D85= 26.0 D30= 0.0481 Cu= 102.80 USCS= Atterberg Limits LL= P1= Coefficients D60= 0.641 D15= 0.0095 Cc= 0.58 Classification AASHTO= Remarks Tested/Calculated by M.Holtz Reviewed by M.Blackwell sampled on 8/3/09, ran on 8/6/09. D50= 0.273 D10= 0.0062 Source of Sample: s -2, El 58', 2 -2.5' deep, HA -C Date: 8/6/09 Elev. /Depth: A.A.R. Testing Laboratory, Inc. Client: Geo Group N.W Project: Cooke Creek Meadows G -2742 Project No: 09 -105 Plate 195 PLATE B3 APPENDIX C USDA GRAIN SIZE DISTRIBUTION GEO Group Northwest, Inc. • • Textural Triangle U.S.D.A. 70 1. 80 100% clay 80 1 MAYA 10 20 30 40 4 �r o SO NAYNAYA $ ,0 4 V 304° AVAI .• 60 A4_ Clay _. 7: 111WilAi ZO 2 � . .80 ....sar VONALVAAVAi •0 80 100% sand AIWA% 70 80 80 40 .4411.1..- Pineal seed Shaded area is applicable for design of infiltration BMPs 30 20 10 100% sl Figure 3.27 USDA Textural Triangle Source: U.S. Department of Agriculture 3 -74 Volume ill — Hydrologic Analysis and Flow Control BMPs February 2005 PLATE Cl • UNITED PATES DEPARTMENT OF AGRICULTURE (USDA) PERCENT PASSING . I GRAVE_ SAND CURSE FINE I VC C F VF SILT CLAY MSTAIWINM masams: . 100 0 80 70 60 6 4 " 2" I. • I , • ; ' I 50 : • t---; . ; 1 40 30 • I ; ! 1 1 20 10 I j . ik I !! ; • !I: ; I • I. 620 440 460 0100 4200 42;70 .002mm . I L. I • • ...,__1:.,.._. •:1--•. H:1' : : 1 I ! . • 1 . I '. ! i • .1 ; . . !I I 1 . ; : . • .. . • 1 1 . ; i •• ' I 1 1 ' • ' • ' H I .74 : : 7 ;. _.:_. - I ..,......___,IiLi4.i....1..._......___;.L...;.2..._:_______....... 152 76 38 19 9.5 4 75 2.0 850 425 250 160 75 45 2 I ! 1000 MILLIMETRES MICRONS 100 10 1.0 0.1 .01 001 .0001 UNITED STATED DEPARTMENT OF AGRICULTURE TEXTURAL TRIANGLE SUMMARY Dio = mm SAND = 13.8 % 030 .-,-.- mm SILT= 71.2 % No = mm CLAY = 15.0 % Du = mm pc . mm THIS SOIL IS CLASSIFIED AS HYDROLOGIC SOIL GROUP IT IS TYPICALLY DESCRIBED AS SAMPLE DESCRIPTIONS SAMPLE LOCATION: HA-A at 3 - 3.5 ft DATE SAMPLED : 8/3/09 BUILDING PERMIT NO.: OTHERS: GEO "•••••••••• Group Northwest, Inc. GootachnIcal Engbigere. Gsalogins, & EmoftmmamMftismftm GRAIN SIZE DISTRIBUTION COOKE CREEK MEADOWS JOB No. G-2742 TESTED DATE 8/10/09 PLATE C2 111 UNITED II1ATES DEPARTMENT OF AGRICULTURE (USDA) PERCENT PASSING GRAVE_ SAND COARSE IVCICIM1 F VF SILT CLAY USSTANDARD EVES: 100 90 8" G'' 3" 2" l'A" I 80 1- , 1 ! I ! j # 0 .420 #40 a60 #100 4200 .002mm ! ! • a —4. I • I I ; !• I ; ; • • . ! I • : I , • !!. -;- ! I ,■1'. '1; .1; ! : I j I ; ! i i ! • • 152 TO 38 19 95 475 2.() MILLIMETRES 850 425 250 150 75 45 MICRONS 1000 100 10 1.0 0.1 .01 .001 .0001 UNITED STATED DEPARTMENT OF AGRICULTURE TEXTURAL TRIANGLE' SUMMARY Dto = mm Coo= mm = mm Du = mm Dc mm SAND = 24.6 SLT= 63.9 % CLAY = 11.5 THIS SOIL IS CLASSIFIED AS HYDROLOGIC SOIL GROUP IT IS TYPICALLY DESCRIBED AS SAMPLE DESCRIPTIONS SAMPLE LOCATION: HA-B at 3 - 3.5 ft DATE SAMPLED : 8/3/09 BUILDING PERMIT NO.: OTHERS: GEO Group Northwest, Inc. Gamer:Sakai Engineers, GsoIog & Environmental Scientists GRAIN SIZE DISTRIBUTION COOKE CREEK MEADOWS JOB No. G-2742 TF-STUI CHKD DATE 8/10/09 PLATE C3 • UNITED STATES DEPARTMENT OF AGRICULTURE (USDA) PERCENT PASSING GRAVE_ SAND COARSE VC iF vF SILT CLAY uSsT&Nueno • 8" 6 4 3 2"'h" 1 ,h 14 1 #10 4J40 U lill 11 ! 1 : 1 ' ; , • I, I , 1 ' , 1 : ; ,F77 ', __,____1111*, 90 ; 1 • , f, 1 1 1 1 11 i . I I I ; ! •1 1 ; ' ; ; • ; i • , ' ; ! ; ; ;. BO , . i 1 • , t 1 ' ', t -1-r"4-7- ;■ !I. 11 • , i • ; i , ,. • ! ! . ; ; : :,; +iTh 7-7---- • ! i :17-7! ; ' ; : ■ 1 ! l'',, , I, , : • ., • . 1 i ! i i ' • I : ; 70 1, "; " r : • i 1 ; • , • I, ' ; Li, 17-1-1-t-i I • 1! !I : — rt---rt- : ! '''-1- - ' i ; --/----- • ' . : , i :..1, ' . ii; I P.■ , I i ii1:1?.i ■j ' I : : ; '1 • , lil; if i 1 L .. r -:1-i- -" -- - --.--44-■- . I i I i --' i ' I : I , ' , 1 . ' ! 1 ''. ;J.; ; I : 1 1 III: '. • I, 1 11: : , 1 50 , 1 , 11 1 11 : ; , ' ; ■ . 1 1 : : . .. • i , i • 1 ' , , i 11111 1 I 1 I 1 ' I . '. . i 1 , 1 i , , . - --! ; 1 • , - - -4-- • 1 ' 1 1 , - i- -7-4-- --.---, 1 0, :. I .1 ; ; 1 1 --. j111111 : ; ; ; • : I ' UI;III ; 1 ; I Hi? I i I i .. !: : i i I • Hifi': !!: ' i, ; . ; ; i : ; i; I 1 I ; ! ■, 1 ; ; ____[......H______ i ; ' ' i I • : - I. 1 1. -..._i....t.,..2. 1 : i 1 1 1 , '• 1".. • . , :1 : ' • i • . : 1 ; • 1 t '1 • . * ! • 1 • ■ "7 -'-- 1 -7- - . . ! i ! • • '• - 11 ','''. ' --,--t----7-- ; • -:-:-.1 , . Ii: . . f ! ; - 7---,,- . ' ; II 1 . . ;: ; . . • ' • • : i : ; . ; • : 1 1 ; . : 11 . ' 75 • ' ' li ; • 111 1 [--- 152 76 38 19 95 4.75 2.0 850 425 250 150 45 2 MILLIMETRES 1 MICRONS • . 1000 100 10 1.0 0.1 .01 .001 .0001 UNITED STATED DEPARTMENT OF AGRICULTURE. TEXTURAL TRIANGLE' SUMMARY Dic mm SAND 52.7 030 = mm SILT= 42.2 % D60 = mm CLAY = 5.1 % ou= mm ou = RIM THIS SOIL IS CLASSIFIED AS HYDROLOGIC SOIL GROUP . IT IS TYPICALLY DESCRIBED AS SAMPLE DESCRIPTIONS SAMPLE:LA=1M HA-C at 2 - 2.5 ft DATE SAMPLED: 8/3/09 BUILDING PERMIT NO.: OTHERS: GEO Group Northwest, Inc. Geotechnica1Engtrteers, Geologies* & Environmental Scientists GRAIN SIZE DISTRIBUTION COOKE CREEK MEADOWS JOB No. G-2742 TESTED CHKD 1 DATE 8/3/09 PLATE C4 Group Northwest, Inc. Geotechnical Engineers, Geologists, & Environmental Scientists 7CENE ) MAR 31 2009 • NATI r :,E;�T Group Northwest, Inc. Geotechnical Engineers, Geologists & Environmental Scientists July 17, 2008 G -2742 Mr. Todd Smith Cooke Riverside Properties, LLC PO Box 97193 Tacoma, WA 98497 Subject: GEOTECHNICAL ENGINEERING STUDY Cooke Creek Meadows Proposed Cottage House Development 13325 MacAdam Road South Tukwila, Washington Dear Mr. Smith: GEO Group Northwest, Inc., conducted this geotechnical study for the purpose of evaluating the site conditions, infiltration, and providing site development recommendations for the proposed development of the lot with nine new cottage -style residential structures. The scope of our services included reconnaissance of the project site, review of a preliminary conceptual site plan sketch, excavation of nine test pits to characterize the subsurface conditions in the area of the proposed development, logging of the soil and groundwater conditions encountered in the test pits, laboratory analysis of the soil samples, evaluation of the infiltration potential of the site soils, engineering analysis, and preparation of this report. The parcel consists of two existing lots (tax lots 7340600983 & 7340600982), both of which are generally rectangular in shape. The east lot (tax lot 7340600982) is occupied by a single - family residential structure that we understand will be demolished as part of the proposed site redevelopment. The site soils encountered in the test pits consist of topsoil, silt, glacial till, and glacially consolidated silt. No groundwater seepage was encountered. It is our evaluation that the site soils are not suitable for infiltration of storm water. Because the site soils consist predominately of silt they are considered to be moisture sensitive and are not recommended to be used as structural fill material for the support of structural elements. 13240 NE 20th Street, Suite 10 • Bellevue, Washington 98005 Phone 425/649 -8757 • Fax 425/649 -8758 • July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page ii Based on the findings of this study it is feasible to short plat the parcel and residentially develop the lots. Residential structures may be supported on conventional spread footing foundations, however loose soils should be removed and the foundation footings supported on the dense undisturbed site soils, or on compacted structural fill that extends down to the dense soil. Structural fill supporting foundation footings should consist of a granular material, such as a pit - run sand and gravel or crushed rock, and structural fill supporting structural elements should be compacted to a minimum of 95% of the material's maximum dry density as specified in the Structural Fill section of this report. These and other geotechnical issues are discussed in the attached report. Please call if you have any questions. Sincerely, GEO GROUP NORTHWEST, INC. Wade J. Lassey Project Engineering Geologist William Chang, P.E. Principal EXPIRES: 2/19//',' I GEO Group Northwest, Inc. GEOTECHNICAL ENGINEERING STUDY COOKE CREEK MEADOWS ' PROPOSED COTTAGE HOUSE DEVELOPMENT 13325 MACADAM ROAD SOUTH ' TUKWILA, WASHINGTON GGNW Project No. G -2742 ' SITE DESCRIPTION ' The project site is located at the northwest corner of the intersections of MacAdam Road South, South 134th Street, and 43`d Avenue South, within the City limits of Tukwila, Washington, as GEO Group Northwest, Inc. July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page 2 not available at the time this study was performed. According to a preliminary proposed site section by KVA Architecture, dated September 12, 2007, the development will generally conform to the existing site topography. SUBSURFACE CONDITIONS A total of nine exploratory test pits were excavated to characterize the site soils in the proposed site development area east of the drainage swale. The test pits ranged in depth from 2.5 to 6 feet. According to the area geologic map1, the project site soils are mapped as Younger Gravel (Qyg), consisting chiefly of sand and pebble gravel. However, the site soils encountered consisted of topsoil, silt, glacial till, and glacially consolidated silt. Younger gravel was not encountered. The soils are variable across the site, but generally consist of soft brown topsoil to a depth of about 2 feet ( ±) underlain by mottled tan to gray stiff to very stiff silt or very dense glacial till. The glacial till consists of silt with some sand and gravel that was deposited by and over - ridden by the glacier during . the last ice age some 10,000 to 15,000 years ago. Some of the glacial till soils also contain cobbles and boulders. Fill consisting of loose to medium dense silt was encountered in two test pits, TP -7 and TP -9, to a depth of about 5 feet. Soils below the fill consisted of very dense glacial till and glacially consolidated silt. No groundwater or water seepage was encountered in the test pits. During the wet months, we anticipate some seepage could be encountered as a result of perched water accumulating on top of the stiffer silts and glacially consolidated soils or sheet flowing onto the site from the up- gradient property to the south. Please refer to the test pit logs in Appendix A at the back of this report for a more detailed description of the soils encountered. The approximate location of the test pits are illustrated on the Topographic Site Plan, Plate 2. Minard, J. P., 1985, Geologic Map of the Marysville Quadrangle, Snohomish County, Washington, Dept. Of the Interior, U.S. Geological Survey Miscellaneous Field Studies, Map MF -1743, 1:24,000 GEO Group Northwest, Inc. July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page 3 SEISMIC CONSIDERATIONS Based on the soil conditions encountered, the site is seismically classified as Site Class C (very dense soil), in accordance with Table 1613.5.2 of the 2006 International Building Code (IBC). The slopes on the parcel appear to be stable. No signs of slope instability was observed, such as tension cracks, slumps, slides, or scarps, and no geotechnical mitigation is recommended, such as steep slope building setbacks. The potential for liquefaction and/or lateral spreading is very low based on a lack of groundwater and the presence of dense soil. No known faults intersect the subject property and the risk of surface rupture is low as a result of a large magnitude seismic event. No mitigation measures are recommended, with the exception of the addition design criteria for seismically induced dynamic soil loads on permanent basement and retaining walls. DISCUSSIONS AND RECOMMENDATIONS Although grading and finished floor elevation plans were not available, based on discussions with the property owner, Mr. Smith, we anticipate that most of the homes will have daylight basements or basement parking garages. Based on the existing site grades and the proposed locations of the homes, we anticipate temporary excavations of up to about 10 feet ( ±) may be required for construction of the house foundations. Some homes may require minimal excavation. Homes along the south property line may have issues with temporary excavations encroaching onto the neighboring property unless temporary shoring is installed. The main geotechnical issues for the project include site preparation and earthwork considerations, temporary shoring considerations, subgrade preparation and soil bearing design criteria for foundations, slab -on -grade floor subgrade preparation and capillary break recommendations, subsurface drainage and infiltration considerations, and subgrade preparation and section recommendations for pavement. GEO Group Northwest, Inc. July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page 4 INFILTRATION/DISPERSION The site soils consist of very low permeability silts and glacially consolidated soils that are not suitable for infiltration of storm water. We recommend storm water be directed to the drainage Swale and /or storm water system, if available. If feasible, we recommend dispersing or utilizing a bioswale system and discharging storm water to the drainage swale /wetland area in the western portion of the parcel. The use of permeable pavements is not recommended due to the poor infiltration characteristics of the site soils. SITE PREPARATION AND GENERAL EARTHWORK Erosion Control The silty site soils have a moderate to high erosion potential. As a precaution, silt fencing should be installed down slope of the construction area(s). A crushed rock construction entrance or the existing driveway should be used to mitigate tracking of mud onto the street by trucks. We recommend that the site work be performed during the dry summer months due to the moisture sensitivity of the site soils. During wet weather, exposed site soils should be covered with straw mulch and cut slopes protected with plastic sheeting to mitigate erosion. Crushed rock check dams, hay bales, and silt fencing should be used as needed to reduce the velocity and suspended sediment in the storm water runoff. Cuts and Fills Under no circumstances should temporary excavation slopes be greater than the limits specified in local, state and national government safety regulations. It is the responsibility of the contractor to provide a safe work environment. If water seepage is encountered, the excavation should be halted and the geotechnical engineer should evaluate the site conditions. Temporary cuts should be sloped at an inclination no steeper than 1H:1V (Horizontal:Vertical) in loose to medium dense soils. Very dense glacial till & glacially consolidated soil may be sloped at up to 1H:6V. If temporary excavations sloped with these inclinations cannot be constructed due to property line GEO Group Northwest, Inc. July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page 5 encroachment, we recommend either acquiring a temporary construction easement from the neighboring property owner, or installation of temporary shoring. If temporary excavations will undermine utilities, such as along the south property line, we recommend relocating the utilities or installing temporary shoring. Utility trench excavations deeper than 4 feet should be supported with trench boxes or the trench sidewalls should be sloped back as recommended above, such that workers in the trench are not susceptible to trench sidewall caving. Permanent cut and fill slopes should be inclined no steeper than 211:1 V. Permanent 2H:1 V fill slopes should be compacted to a minimum of 90 percent of the material's maximum dry density. Permanent slopes of 3H:1 V, or less, are recommended if they are to be mowed and maintained. Temporary Shoring Temporary shoring should be installed if the open cut (sloped cut) temporary excavation will encroach into the neighboring property or if utilities will be undermined. The need for temporary shoring should be determined prior to the start of excavation so that it can be installed as part of the excavation process. Temporary shoring may consist of ecology block walls or soldier pile with lagging walls, as discussed below, depending on the excavation requirements and conditions. Ecology Block Wall Temporary shoring may consist of stacked ecology blocks, up to six feet (3 blocks) high, provided the near vertical open cut required to install the blocks is stable. Ecology blocks are typically 5' long by 2' wide by T deep, and made of concrete. The base of the bottom block should be keyed into the ground 0.5 foot and the wall battered back into the hillside at 1H:8V. Gaps behind the wall should be filled with 5/8 inch minus crushed rock. Soldier Pile Wall Temporary shoring may consist of a cantilever soldier pile and lagging wall for cuts up to 14 feet (±) in height. Walls greater than 14 feet (±) may require tie -backs or internal struts, which increases the shoring cost. It may be possible to limit the height of the shoring by raising the GEO Group Northwest, Inc. July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page 6 bottom floor elevation of the structure and /or by moving the structure further away from the property line and by open cutting at a 1 H:1 V slope behind the top of the soldier pile wall. Soldier piles, are installed by first drilling a hole, setting the steel wide -flange beam in the hole and grouting the beam in the hole. Excavation in front of the wall would then be carried out in about 4 -foot excavation lifts to allow for the installation of timber lagging behind the soldier piles. Based on the soil conditions, temporary cantilever shoring walls should be designed for an active soil pressure of 35 pcf equivalent fluid weight for level ground behind the wall. For sloped ground behind the wall, a surcharge load equivalent to 50 percent of the soil height above the wall should be considered in addition to the above active soil pressure. Surcharge loads above the shoring, such as driveway traffic, should be considered as equivalent to two (2) feet of soil height (130 pcf) in addition to the active soil pressure. The active soil pressure should act on one pile- spacing above the excavation line and one pile - diameter below. To counter the active soil pressure, an allowable passive pressure of 350 pcf equivalent fluid weight can be used. The passive pressure acts over twice the soldier pile width to resist lateral forces. The passive resistance in the top foot of the soldier pile should be ignored due to potential soil disturbance. The timber lagging should consist of pressure treated timber designed to resist 50 percent of the apparent lateral soil pressure due to soil arching effects. Structural Fill Structural fill is defined as compacted engineered fill soils used to support building foundation loads, floor slabs, patios, porches, retaining walls, sidewalks, and pavements. In general, silt site soils are moisture sensitive, have a high moisture content, and could be difficult to compact to structural fill compaction specifications depending on the material's moisture content and the time of year that construction takes place. We do not recommend utilizing the silty on -site soils as structural fill material. We recommend importing a granular material, such as a pit -run gravelly sand, or crushed rock. Other materials should be reviewed by the geotechnical engineer. Soils containing organics, debris and /or rubble, should not be used as structural fill. GEO Group Northwest, Inc. July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page 7 Structural fill should be placed and compacted at the material's optimum moisture content (+ 3 percent) and compacted in 10 -inch ( ±) thick lifts (depending on the material). Structural fill placed below building foundations and slab -on -grade floors should be compacted to a minimum of 95 percent of the material's maximum dry density, as determined by ASTM Test Designation D -1557 (Modified Proctor). Under pavements and sidewalks structural fill should be compacted to 90 percent, with the exception of the top 12- inches which should be compacted to 95 percent. Fill adjacent to foundations should be compacted to 90 percent (95 percent if supporting slabs, patios, porches, or other structural elements). FOUNDATION DESIGN. CRITERIA Structures may be supported on conventional spread footings, consisting of either strip or column footings. We recommend foundation footings be supported directly on the dense undisturbed soil that underlies the site, or on structural fill that extends down to the dense soil. Uncontrolled fill soils on the site should be removed below the footprint of the buildings. Structural fill below footings should create a prism that extends out and below the footing at 1H:1V. As a result, the foundation excavation should be wider than the foundation footprint. For 2 feet of structural fill, the structural fill should extend out beyond the footing by 2 feet on both the exterior and interior of the footing and the footing should be centered on the structural fill. The following foundation design criteria are applicable to spread footing foundations that are supported as described above: • Allowable bearing pressure, including all dead and live loads: Dense site soil or structural fill • Minimum depth to bottom of perimeter footing below adjacent final exterior grade: • Minimum depth to bottom of interior footings below top of floor slab: • Minimum width of strip footings: GEO Group Northwest, Inc. = 2,500 psf = 18 inches = 12 inches = 16 inches July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page 8 • Minimum lateral dimension of column footings: • Estimated post- construction settlement: — Across building width: = 24 inches = 1/4 inch = 1/4 inch A one -third increase in the above allowable bearing pressures can be used when considering short-term transitory wind or seismic loads. Lateral loads can also be resisted by friction between the foundation and the supporting compacted fill subgrade or by passive earth pressure acting on the buried portions of the foundations. For the latter, the foundations must be poured "neat" against the existing undisturbed soil or backfilled with a compacted fill meeting the requirements of structural fill. Our recommended parameters are as follows: - Passive Pressure (Lateral Resistance) • 350 pcf equivalent fluid weight for dense site soils and structural fill - Coefficient of Friction (Friction Factor) • 0.35 for dense site soils and structural fill BASEMENT WALLS AND RETAINING WALLS Permanent basement walls restrained horizontally on top are considered unyielding and should be designed for a lateral soil pressure under the at -rest condition. Conventional reinforced concrete walls free to rotate on top (cantilever walls) should be designed for an active lateral soil pressure. Active Soil Pressure Cantilever walls that are designed to yield an amount equal to 0.002 times the wall height, should be designed to resist the lateral earth pressure imposed by an equivalent fluid with a unit weight of 35 pcf for level backfill above the wall. At -Rest Soil Pressure Walls supported horizontally by floor slabs are considered unyielding and should be designed for lateral soil pressure under the at -rest condition. The design lateral soil pressure should have an equivalent fluid pressure of 45 pcf for level ground above the wall. GEO Group Northwest, Inc. July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page 9 Seismic Earth Pressure In addition to the above lateral soil pressure, a rectangular pressure of 6H should be added to the lateral soil pressure for permanent basement and retaining walls to account for seismically induced dynamic soil loads. Passive Earth Pressure and Base Friction The available passive earth pressure that can be mobilized to resist lateral forces may be assumed to be equal to 350 pcf equivalent fluid weight for both undisturbed soils and engineered structural backfill. The base friction that can be generated between concrete and undisturbed bearing soils or engineered structural backfill may be based on an assumed 0.35 friction coefficient. Basement Wall Drainage A vertical drain mat, Miradrain 6000 or equivalent, may be used to facilitate drainage behind basement and retaining walls, or the walls may be backfilled with a clean free - draining gravelly sand or crushed rock material. We recommend both installing the drain mat and backfilling with a clean granular material. In addition, basement walls should be waterproofed. To install a vertical drain mat, the plastic core of the mat should be placed against the basement wall with the filter fabric side facing the backfill. The drain mat should extend from the finished surface grade down to the base of the wall. The bottom of the drain mat should be bedded in the washed drain rock surrounding the footing drain, as illustrated on the Footing Drain Detail, Plate 4. Footing drains must outlet to an appropriate discharge location (to be determined by others). The wall backfill should be compacted to 90 percent, or in accordance with the manufacture's recommendation, to prevent clogging of the geotextile filter fabric. The top twelve (12) inches should consist of relatively impermeable cap soil that is separated from the underlying granular material by a layer of geotextile. The surface should be sloped to drain away from the building wall. Alternatively, the surface can be sealed with asphalt or concrete paving. GEO Group Northwest, Inc. • • July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page 10 SLAB -ON -GRADE FLOORS Subgrade support for slab -on -grade floors should be prepared as recommended for foundations, with structural fill compacted to 95 percent of the material's maximum dry density, in accordance with the specifications for structural fill. It is recommended that the subgrade for floor slabs and foundations be prepared at the same time. Slab -on -grade floors should be placed on a capillary break to prevent wicking of moisture through the slab. The capillary break should consist of a minimum of six (6) inch thick free - draining layer of 1.5 inch minus gravel containing no more than five (5) percent fines passing the No. 4 (1/4 -inch) sieve. To reduce water vapor transmission through the slab we recommend installing a 10 -mil reinforced vapor barrier, such as Moistop® by Fortifiber Corporation, between the capillary break and concrete floor slab. Two to four inches of sand may be placed over the membrane for protection during construction (optional). DRAINAGE Water should not be allowed to stand in areas where footings, slabs, or pavements are to be constructed. During construction, loose surfaces should be sealed at night by compacting the surface to reduce moisture infiltration into the soils. Final site grades should allow for drainage away from building structures. We suggest that the ground be sloped at a gradient of three (3) percent for a distance of at least ten feet away from buildings except in areas that are to be paved. Final site grades and impervious areas should be designed to collect surface water into catch basins and be tight -lined for discharge into the storm system or an appropriate discharge location. Water seepage is not anticipated during site excavation, if excavation takes place during the drier summer months. If water seepage is encountered, the geotechnical engineer should evaluate the site conditions. Provided the excavation is stable, the bottom of the excavation may be sloped to shallow sump pits and the water pumped to an appropriate discharge location. GEO Group Northwest, Inc. July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page 11 Footing Drains A subsurface footing drain should be installed at the base of basement walls, at an elevation that is below the basement floor slab, and around the perimeter of all foundations. The footing drain should consist of a four (4) inch minimum diameter, perforated, rigid drain pipe laid at or near the bottom of the footing with a gradient sufficient to generate flow. The drain line should be bedded washed drain rock and the drain rock should be protected (wrapped) with geotextile filter fabric, such as Mirafi 140N, or equivalent, as illustrated on the Footing Drain Detail, Plate 4. Roof, yard, and other drain lines should not be connected to the footing drain system. The footing drain should be separately tightlined to the discharge point. We recommend that sufficient cleanouts be installed to allow for periodic maintenance of the footing drains and roof down -spout tightline systems. Roof and subsurface drains must discharge to an appropriate location, such as a dispersion or bioswale system by the drainage swale /wetland, or to the storm drain system in MacAdam Street (or a combination). Storm water detention may be required. PAVEMENTS Pavement Subgrade The adequacy of pavements is strictly related to the condition of the underlying subgrade. If this is inadequate, no matter what pavement section is constructed, settlement or movement of the subgrade will be reflected up through the paving. The pavement subgrade should be dense and unyielding. The subgrade should be grubbed, and all topsoil, organic soil, loose soil, and soil containing debris should be removed. We recommend the remaining subgrade be compacted with a large vibratory roller and proof - rolled under the observation of the geotechnical engineer. If the subgrade soil is not dense and unyielding, the geotechnical engineer should be requested to provide subgrade stabilization recommendations. Prior to paving, the subgrade should be proof - rolled with a loaded dump truck under the observation of the geotechnical engineer and any areas of unstable subgrade should be stabilized as recommended by the engineer. GEO Group Northwest, Inc. • • ' July 17, 2008 G -2742 Geotechnical Engineering Study Page 12 Cooke Creek Meadows The pavement section for county or city roadways should follow their design standards. For private parking areas and driveways we recommend the following minimum pavement section: ' MINIMUM PAVEMENT SECTION HEAVY TRAFFIC AREAS ' Class "B" Asphalt Concrete (AC) 3- inches, over Crushed Rock Base (CRB) 6- inches, or Asphalt Treated Base (ATB) 3- inches LIGHT TRAFFIC AREAS ' Class "B" Asphalt Concrete (AC) 2- inches, over Crushed Rock Base (CRB) 4- inches, or ' Asphalt Treated Base (ATB) 2- inches The minimum pavement section above may not be acceptable if there is evidence of instability in ' the subgrade. In the event of poor, yielding, or unstable subgrade conditions, we should be requested to review the site conditions and provide subgrade stabilization recommendations. LIMITATIONS This report has been prepared for the specific application to the subject project. The findings and recommendations stated herein are based on our field observations, the subsurface conditions encountered in our site exploration, our experience, and judgement. The recommendations are ' our professional opinion derived in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this ' area and within the budget constraint. No warranty is expressed or implied. In the event that soil conditions vary during site work, GEO Group Northwest, Inc. should be notified and the recommendations herein re- evaluated, and where necessary, be revised. GEO Group Northwest, ' Inc. should be retained to review the final design plans to confirm the validity of the recommendations contained in this report if there are significant changes to the project as udescribed herein. ' GEO Group Northwest, Inc. • July 17, 2008 Geotechnical Engineering Study Cooke Creek Meadows G -2742 Page 13 PLAN REVIEW AND CONSTRUCTION MONITORING GEO Group Northwest, Inc., should be retained to perform a general review of the final design plans and specifications to verify that the earthwork, foundation, and other recommendations have been properly interpreted and implemented in the design, engineering, and plan documents. During construction, GEO Group Northwest should provide geotechnical construction monitoring /inspection services. This will allow us to confirm that the subsurface conditions are consistent with those described in this report and allow design changes in the event subsurface conditions differ from those anticipated prior to the start of construction. It will also allow us to evaluate whether the geotechnical aspects of the construction activities conform to the contract plans, specifications, and geotechnical engineering recommendations. Please contact us if you have any questions regarding this report. Sincerely, GEO Gr • u • Northwest, Inc. ek.,t1L.,/ Wade J. Lassey Engineering Geologist William Chang, P.E. Principal Attachments: Illustrations Plate 1 Plate 2 - Plate 3 - Plate 4 - Appendix A ' EXPIRES: 2/19/ Vicinity Map Site Plan Preliminary Site Development Sketch Footing Drain Detail USCS Soil Classification Legend & Test Pit Logs GEO Group Northwest, Inc. • ILLUSTRATIONS G -2590 Adapted from "The Thomas Guide," 2007. 0 1000' 2000' Approximate Scale: 1 inch =1000 feet GEO Group Northwest, Inc. Geotechnical Engineers, Geologists, & Environmental Scientists VICINITY MAP PROPOSED COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON SCALE As Shown DATE 7/15/08 MADE WJL CHKD WC JOB NO. G -2742 PLATE 1 4 p GRAPHIC SCALE ▪ m w � ( of Pew ) � I/ (63 l — •6.7 g9 iverside R Tracts Inter rb ,or` fen fs' 30' Found 2 r 4' high pipe - 1. .: south a 2.8r east • f set rebor w /Cap west and 6' wood fence pointed O Set rebor . /cap #23604 • Found pipe or rebar xt Hydrant ny Power pole • Deciduous Tree • Evergreen Tree Mil Catch Basin pd Gas Valve • Water Valve m sewer manhole ® storm drain manhole m40 water meter —S — sewer tine — g — gas line —w— water tine —so-- stone drain Case o 0 power pole ./light 7e' : 516 WEST 262.07 • t TP-8 7Gte wo° wetland fine (Weft done by o finest•.• �l nagging ars ebb o° tank (an f TAX LOT 7.340600983 Wetland A 717s.f. 1.' sM EAST N9013000'E 5,9 } 20.00' • South 1341/7 Street (Unopened) West end wood fence & east end hog wire fence 5' wood fence 41 .. t f apron 5-r yon � north edge asphalt driveway Centerline So. 134th St. { th -South CL of Sec. 15. T23N. R4E LEGEND TEST PIT NUMBER & *Tp..1 APPROXIMATE LOCATION Note: According to Mr. Todd. Smith, we understand that the Wetland B area shown on this plan was reclassified as a "Non- Wetland Area" prior to this study. This Topographic Site Plan Adapted From A Site Survey by Schroeter Land Surveying, dated February 2, 2007, for Mr. Todd Smith 4Jrd Ave. South 30' Group Northwest, Inc. Geotechnical Engineers, Geologists, & Environmental Scientists TOPOGRAPHIC SITE PLAN PROPOSED COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON SCALE As Shown DATE 7/15/08 MADE WJL CHKD WC , JOB NO. G -2742 PLATE • I 01 .4 I lo' 0 40' 80' Approximate Scale: 1 inch = 40 ft This Conceptual Site Plan Adapted From Concept Site Plan, provided by Mr. Todd Smith, date 6- 10 -08. - ,:. • iV 77 Group Northwest, Inc. Geotechnical Engineers, Geologists, & Environmental Scientists CONCEPTUAL SITE PLAN PROPOSED COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH -TUKWILA, WASHINGTON SCALE As Shown DATE 7/15/08 MADE WJL CHKD WC JOB NO. G -2742 PLATE • • Slope to drain Basement Wall OTHER SOIL 0 • 0 o 0 0 0 WALL BACKFILL VERY DENSE GLACIAL TILL & GLACIALLY CONSOLIDATED SOIL 6 GEOTEXTILE FILTER FABRIC (Mirafi 140 N, or equivalent) WASHED DRAIN ROCK WALL FOOTING DRAIN 4 -inch diameter rigid perforated PVC pipe 0 0 0 O 0 0 0 O ° 0 0 o ° 0 O 0 err Water- Proofing On Wall Face & Vertical Drain Mat (Mlradrain 6000 or equivalent) OR Clean Free • Draining Backfill SLAB CAPILLARY BREAK STRUCTURAL FILL FOOTING NOT TO SCALE NOTES: 1.) Do not replace rigid PVC pipe with flexiible corrugated plastic pipe. 2.) Perforated or slotted PVC pipe should be tight jointed and laid with perforations or slots down, with positive gradient to discharge. 3.) Do not connect roof downspout drains into the footing drain line system. 4.) Backfill should be compacted to 90% of maximum dry density based on Modified Proctor (ASTM D1557 -91). The top 12- inches to be compacted to 95% of maximum dry density if backfill is to support sidewalks, driveway, etc. Group Northwest, Inc. Geotechnical Engineers, Geologists, & Environmental Scientists FOOTING DRAIN DETAIL PROPOSED COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON SCALE NONE DATE 7/17/08 MADE WJL CHKD WC JOB NO. G -2742 PLATE 4 APPENDIX A G -2590 TEST PIT LOGS • LEGEND 0 SOIL CLASSIFICATION AND PENETRATION TEST UNIFIED SOIL CLASSIFICATION SYSTEM (USCS) MAJOR DIVISION GROUP SY19L':OL TYPICAL DESCRIPTION LABORATORY CLASSIFICATION CRITERIA . COARSE- GRAINED SOILS More Than Half by Weight Larger Than No. 200 Sieve GRAVELS (More Than Half Coate Grains Larger Than No. 4 Sieve) CLEAN GRAVELS (little or no fines) GW WELL GRADED GRAVELS, GRAVEL -SAND MIXTURE, LITTLE OR NO FINES DETERMINE PERCENTAGES OF GRAVEL AND SAND FROM GRAIN SIZE DISTRIBUTION CURVE COARSE GRAINED SOILS ARE CLASSIFIED AS FOLLOWS: < 5% Fine Grained: GW, GP, SW, SP >12 % Fine Grained: GM, GC, SM, SC 5 to 12% Fine Grained: use dual symbols Cu = (D60 1 D10) greater than 4 Cc = (0302) / (D10.060) between 1 and 3 GP POORLY GRADED GRAVELS, AND GRAVEL -SAND MIXTURES LITTLE OR NO FINES NOT MEETING ABOVE REQUIREMENTS DIRTY GRAVELS (with some fines) GM SILTY GRAVELS, GRAVELSANDSiLT MIXTURES CONTENT OF FINES EXCEEDS 12% ATTERBERG LIMITS BELOW "A" LINE or P. LESS THAN 4 I. GC CLAYEY GRAVELS, GRAVEL - SAND -CLAY MIXTURES ATTERBERG LIMITS ABOVE "A" LINE . or P.I. MORE THAN 7 SANDS (More Than Half Coarse Grains Smaller Than No. 4 Sieve) CLEAN SANDS (little or no fines) SW WELL GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES Cu = (060 / 010) greater than 6 Cc = (D302) / (D10 • D60) between 1 and 3 • SP POORLY GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES NOT MEETING ABOVE REQUIREMENTS DIRTY SANDS (with some fines) SM SILTY SANDS, SANG SILT MIXTURES CONTENT OF FINES EXCEEDS 12% ATTERBERG LIMITS BELOW "A" LINE with P.I. LESS THAN 4 SC CLAYEY SANDS, SAND -CLAY MIXTURES ATTERBERG LIMITS ABOVE "A" LINE with P.I. MORE THAN 7 FINE- GRAINED SOILS More Than Half by Weight oar0er Than No. 200 Sieve SILTS (Below A-Line on Plasticity Chart, Negligible Organic) Liquid Limit < 50% ML INORGANIC SILTS, ROCK FLOUR, SANDY SILTS OF SLIGHT PLASTICITY 6U PLASTICITY INDEX ( %) ] N [ y v 0 O O O G I I I I A -Line ......... ' PLASTICITY CHART _ FOR SOIL PASSING NO. 40 SIEVE Liquid Limit > 50% MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS, FINE SANDY OR SILTY SOIL CH or OH Ili Ili CLAYS (Above A -Line on Plasticity Chart, Negligible Organic) Liquid Limit < 30% CL INORGANIC CLAYS OF LOW PLASTICITY, GRAVELLY, SANDY, OR SILTY CLAYS, CLEAN CLAYS Liquid Limit > 50% CH INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS CL or OL IpA/� MH or OH ORGANIC SILTS & CLAYS (Below A -Line on Plasticity Chart) Liquid Limit 50% OL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY Wf,MIW OL .r ML Liquid Limit > 50% OH ORGANIC CLAYS OF HIGH PLASTICITY 0 10 20 30 40 50 UQUID 60 70 80 90 100 110 LIMIT ( %) HIGHLY ORGANIC SOILS Pt PEAT AND OTHER HIGHLY ORGANIC SOILS SOIL PARTICLE SIZE GENERAL GUIDANCE OF SOIL ENGINEERING PROPERTIES FROM STANDARD PENETRATION TEST (SPT) U.S. STANDARD SIEVE FRACTION Passing Retained SANDY SOILS SILTY & CLAYEY SOILS Sieve Size (mm) Sieve Size (mm) Blow Counts N Relative Density % Friction Angle th, degree Description Blow Counts N Unconfined Strength qu, tsf Description esc SILT / CLAY #200 0.075 SAND FINE MEDIUM COARSE #40 #10 #4 0.425 2.00 4.75 #200 #40 #10 0.075 0.425 2.00 0 - 4 4 -10 10 - 30 30 - 50 > 50 0 -15 15 - 35 35 - 65 65 - 85 85 -100 26 - 30 28 - 35 35 - 42 38 - 46 Very Loose Loose • Medium Dense Dense Very Dense < 2 2 - 4 4 - 8 8 - 15 15 - 30 a 30 < 0.25 0.25 - 0.50 0.50 - 1.00 1.00 - 2.00 2.00 - 4.00 > 4.00 Very soft Soft Medium Stiff Stiff Very Stiff Hard GRAVEL 19 76 #4 4.75 19 FINE COARSE i.. COBBLES 76 mm to 203 mm Group Northwest, Inc. BOULDERS >203mm GEO Geotechnical Engineers, Geologists, & _ Enviro nmental Scientists 13240 NE 20th Street, Suite 12 Bellevue, WA 98005 ROCK FRAGMENTS > 78 mm - ROCK >0.78 cubic meter In volume Phone (425) 849-8757 Fax (425) 649 -8758 PLATE Al LOGGED BY WJL TEST PIT: TP -1 LOG DATE: 06/24/2008 GROUND ELEV. 61 feet +/- DEPTH ft. USCS SOIL DESCRIPTION SAMPLE No. Water % OTHER TESTS/ COMMENTS 1 — ML SILT, brown, some fine sand, few gravel, medium dense, some - Probe 1.5 ft _ 2 — ML organics /roots, damp SILT, mottled brown/tan, stiff, nonplastic, occasional cobbles, ■ S1 24.3 2 _ damp to moist _ ___M_ I Si 19.2 3 — ML SILT, tan to brown, hard, nonplastic, damp • S2 14.6 4 4 — SILT, lighter brown/tan, mottled, very stiff, nonplastic, — .. ML occasional boulders 2 -3 feet dia., damp II S2 22.9 - Probe 3 in. 5 — 5 — damp (Glacial Till) I S3 14.1 6 • S3 26.4 Total depth of test pit = 5 feet - 6 — 7 No water seepage Total depth of test pit = 6 feet below ground surface (bgs) 7 — — No groundwater seepage encountered 8 LOGGED BY WJL TEST PIT: TP -2 LOG DATE: 06/24/2008 GROUND ELEV. 61 feet +/- DEPTH ft. USCS SOIL DESCRIPTION SAMPLE No. Water % OTHER TESTS/ COMMENTS 1 ML SILT, dark brown, loose, with organics, damp (Topsoil) - Probe 2.3 ft 2 — ML SILT, mottled brown/tan, stiff, nonplastic, occasional cobbles, ■ S1 24.3 _ damp to moist 3 — ML SILT, tan to brown, hard, nonplastic, damp • S2 14.6 - Probe 0 in. 4 — ..... — ..... .. SILT, tan/brown, very dense, with sand and pebble gravel, 5 — damp (Glacial Till) I S3 14.1 — Total depth of test pit = 5 feet 6 — No water seepage 7 — GEO Group Northwest, Inc. Geotechnical Engineers, Geologists, & Environmental Scientists TEST PIT LOGS COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON JOB NO. G -2742 DATE 7/17/08 PLATE A2 LOGGED BY WJL TEST PIT: TP -3 LOG DATE: 06/24/2008 GROUND ELEV. 52.5 feet +/- DEPTH ft. USCS SOIL DESCRIPTION SAMPLE No. Water % OTHER TESTS/ COMMENTS 1 — ML SILT, brown, soft to medium stiff, moist Probe 1 h ML SILT, brown, soft, some organics /roots, moist ■ Si 19.8 S1 3 — ML SILT, reddish brown, soft, nonplastic, moist • S2 34.2 4 3 J _ ■ S2 ML SILT, mottled gray, stiff, nonplastic, moist — – SILT, mottled tan, very stiff, nonplastic, moist • S3 30 – 5 — ML - Probe 5 in. 6 II S3 31.3 7 Total depth of test pit = 5 feet below ground surface (bgs) Very stiff to hard, glacially consolidated, platy, less mottled — — No groundwater seepage encountered • S4 8 LOGGED BY WJL TEST PIT: TP -4 LOG DATE: 06/24/2008 GROUND ELEV. 52.5 feet +/- DEPTH ft. USCS SOIL DESCRIPTION SAMPLE No. Water % OTHER TESTS/ COMMENTS 1 — ML SILT, brown, soft to medium stiff, moist Probe 1 h – S1 35.2 2 3 J ■ S2 27.0 — SILT, mottled tan, very stiff, nonplastic, moist 4 – ML - Probe 5 in. — II S3 31.3 6 Very stiff to hard, glacially consolidated, platy, less mottled — • S4 31.0 – Total depth of test pit = 5 feet 6 — No water seepage 7 — Group Northwest, Inc. Geotechnical Engineers, Geologists, & Environmental Scientists TEST PIT LOGS COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON JOB NO. G -2742 DATE 7/17/08 I PLATE A3 LOGGED BY WJL TEST PIT: TP -5 LOG DATE: 06/24/2008 GROUND ELEV. 55.5 feet +/- DEPTH ft. USCS SOIL DESCRIPTION SAMPLE No. Water % OTHER TESTS/ COMMENTS 1 ML SILT, brown, soft, some surface debris, moist (Topsoil) ■ S1 16.1 _ ML SILT, brown, soft, some organics /roots, moist S1 30.4 -Probe Din. 2 _ _ SILT, brown, very dense, nonplastic, damp II S2 15.5 3 - Probe 1 in 3 – ML SILT, mottled tan, hard, nonplastic, damp —_____ No water seepage III S2 32.1 4 — ML SILT, gray, some sand and gravel, very dense, moist – I S3 14.5 5 . – Total depth of test pit = 4.5 feet below ground surface (bgs) 6 _ No groundwater seepage encountered 7 8 LOGGED BY WJL TEST PIT: TP -6 LOG DATE: 06/24/2008 GROUND ELEV. 70 feet +/- DEPTH ft. USCS SOIL DESCRIPTION SAMPLE No. Water % OTHER TESTS/ COMMENTS – ML SILT, brown, soft, some surface debris, moist (Topsoil) ■ S1 16.1 1 _r.___— -Probe Din. 2 ML SILT, brown, very dense, nonplastic, damp II S2 15.5 3 — Total depth of test pit = 2.5 feet – No water seepage 4 5 6 . 7 _ GEO Group Northwest, Inc. Geotechnical Engineers, Geologists, & Environmental Scientists TEST PIT LOGS COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON JOB NO. G -2742 DATE 7/17/08 I PLATE A4 LOGGED BY WJL I TEST PIT: TP -7 • LOG DATE: 06/24/2008 GROUND ELEV. 70 feet +/- DEPTH ft. USCS SOIL DESCRIPTION SAMPLE No. Water % OTHER TESTS/ COMMENTS 1 ML SILT, brown, soft, moist (Topsoil) 2 - Probe 0 in. — ML SILT, brown, some gravel and cobbles, occasional boulders, - Probe 1 ft 3 – — ML SILT, brown, medium dense, nonplastic, damp (FILL) I Si 17.7 3 4 – 5 Total depth of test pit = 2.5 feet 4 — – ML SILT, gray, some sand and gravel, very dense, moist (Glacial Till) ` S2 9.7 _ 6 Broke unknow n water line to neighboring house. 5 7 – Total depth of test pit = 5.5 feet below ground surface (bgs) 6 — No groundwater seepage encountered 7 — s LOGGED BY WJL TEST PIT: TP -8 LOG DATE: 06/24/2008 GROUND ELEV. 68 feet +/- DEPTH ft. USCS SOIL DESCRIPTION SAMPLE No. Water % OTHER TESTS/ COMMENTS – ML SILT, brown, soft, moist (Topsoil) 1 - Probe 0 in. – 2 ML SILT, brown, some gravel and cobbles, occasional boulders, — dense, damp (Glacially consolidated) III Si 14.3 3 – Total depth of test pit = 2.5 feet 4 — No water seepage _ Broke unknow n water line to neighboring house. 5 6 7 — Group Northwest, Inc. Geotechnical Engineers, Geologists, & Environrrental Scientists TEST PIT LOGS COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON JOB NO. G -2742 DATE 7/17/08 PLATE AS LOGGED BY WJL TEST PIT: TP -9 LOG DATE: 06/24/2008 GROUND ELEV. 65 feet +/- DEPTH ft. USCS SOIL DESCRIPTION SAMPLE No. Water % OTHER TESTS! COMMENTS 1 — • Si 12.9 – -Probe 111 2 — – ML SILT, brown, medium dense, nonplastic, occasional gravel and 3 — cobbles, damp (FILL) ' 4 — II S2 14.0 5 - - - -- _ MI- SILT, tan, hard, moist (Glacially Consolidated) u S3 15.1 – 6 7 Total depth of test pit = 5.5 feet below ground surface (bgs) — No groundwater seepage encountered 8 LOGGED BY TEST PIT: TP- LOG DATE: GROUND ELEV. feet +/- DEPTH ft. USCS SOIL DESCRIPTION SAMPLE No. Water % OTHER TESTS/ COMMENTS 1 — 2 3 4 — 5 6 ' 7 — Group Northwest, Inc. Geotechnical Engineers, Geologists, & Environmental Scientists TEST PIT LOGS COOKE CREEK MEADOWS 13325 MACADAM ROAD SOUTH TUKWILA, WASHINGTON JOB NO. G -2742 DATE 7/17/08 PLATE AS Cooke Creek Mea ows Proposal for Wetland Buffer Reduction City of Tukwila Housing Options Program 12/7/2007 To Director of Community Development, P. FIVE MAR 31 2009 COMMUNfry DEVELOPMENT Cooke Riverside Properties, LLC PO Box 97193 Tacoma, WA 98497 What ESA Adolfson and Sewell Wetland Consultants (SWC) have concluded from site analysis and reviewing-the site as late as February 9, 2009 is the wetland and Southgate Creek can be protected. Furthermore, no erosion has occurred due the activities prior to requesting a tree permit, which was confirmed by Ms. Whiting. Our plan presented by SWC will illuminate how and when this should occur. Valley View Sewer District, as part of our sewer availability submittal that we provided at our Pre -App meeting, will be providing sewer access to the maintenance hole that is located to the west of the wetland along the south boundary. During the construction of an access line we plan to improve the hydrology of the wetland on our site by enlarging and enhancing using plantings described in our plan. This will allow the wetland swale and buffer to retain more water, slow the flow of water as it travels through our site, and improve the habitat of this entire wetland. Please review the design layout of our proposal to find that over 50% of the property remains open space exceeding the criteria of the Housing Options Ordinance. We strategically embraced the wetlands and integrating them into the design layout. Without the Buffer Reduction from 50 to 25 feet two houses would be eliminated from our plan dropping us below the 8 houses required by the ordinance. Regarding water drainage from house roof drains and hard surfaces, we will be presenting a design to channel drainage to and into the landscape, rain gardens, and wetland areas throughout the site. This will help keep plantings green and re- charge water tables of the wetland area which have diminished over the years due to the large development south of our site, and improve the overall nature of the wetland and buffers. Sincerely submitted by, Todd Smith, CEO, Cooke Riverside Properties, LLC. E -mail: Cookecottages @q.com Phone: 253.691.8191 This Project was successfully approved by the Tukwila Community Development Director, 4/4/08. 1 r ESAAdolfsoP MAR 31 2009\ Q.Q.MW1UN TY GeNtz.LQPNENT memorandum date October 16, 2007 to Mr. Todd Smith from Ms. Linda Krippner subject Cooke Property Conceptual Mitigation Plan 5309 Shilshole Avenue Alp Suite 200 Seattle, WA 98107 206.789.9658 phone 206.789.9684 fax www.adolfson.com ESA Adolfson (Adolfson) is pleased to present this conceptual mitigation plan'for the Cooke Property at 13325 Macadam Road South in Tukwila, Washington (Figure 1). This property is currently developed with a single - family residence. The project proposal is to subdivide this approximately one -acre property into two lots for a cottage house development with nine housing units. New homes would be situated on the east portion of the property. Several low impact development strategies are being proposed for storm water treatment on this site. Site Description Macadam Road bounds the Cooke property to the east, and other low - density single- family residential lots surround it to the north, and south. The western edge of the property abuts Southgate Creek, a perennial, fish bearing stream. The east portion of the property is developed with a single family home (Photo 1) and the remainder of the site is dominated by Himalayan blackberry and red alder. The site slopes relatively steeply near the center of the site to a wetland swale on the west portion of the site. The west portion of the site is relatively flat between the wetland swale and Southgate Creek. Wetland Study Summary One wetland (Wetland A) is located on the east portion of the site and one wetland (Wetland B) is located offsite to the north (Figure 2). Adolfson scientists, Linda Krippner and Brooke Sullivan, conducted wetland delineation field surveys on December 5, 2006 and February 16, 2007. The boundary for Wetland B was revised during the wetland verification site visit by Sandra Whiting from the City of Tukwila, on August 6, 2007. Teresa Vanderburg and Brooke Sullivan from Adolfson were present for the City's wetland verification site visit and the wetland memorandum, dated August 13, 2007, was revised accordingly. Wetland A is a depressional wetland located on the west portion of the site at the base of a slope in a drainage swale west of the single - family home. Wetland B is a small slope wetland located offsite to the north. Wetland B is too small to be regulated by the City (Tukwila Municipal Code [TMC] 18.45.80.B.3). Wetland A is an emergent and forested wetland that is contained within a 10 -foot wide swale on the site. Reed canary grass and Himalayan blackberry dominate in open emergent areas (Photo 2) and red alder, Sitka willow and Himalayan blackberry dominate in forested areas (Photo 3). South of the site Wetland A is positioned in a wider depressional area that is dominated by a monoculture of reed canary grass (Photo 4). North of the site Wetland A remains contained in a swale and is dominated by creeping buttercup and Himalayan blackberry Cooke Property October 16, 2007 (Photo 5). The wetland buffer on the site and in offsite areas is dominated by Himalayan blackberry (Photo 6) with some relatively dense stands of red alder and willow also present. The habitat functions of Wetland A and its buffer are limited by the prevalence of non - native invasive species, mainly Himalayan blackberry and reed canary grass. English ivy is also present in some areas of the wetland and buffer. Water quality functions are moderate due to the presence of dense vegetation and the lack of a surface water outlet. Hydrologic functions are moderate due to the position of Wetland A in a closed depression. City of Tukwila Regulations Wetlands and streams in the City of Tukwila are regulated in accordance with the Tukwila Municipal Code (TMC) 18.45. Wetland A is considered a Type 3 wetland because it is less than one acre in size and has two wetland classes (emergent and forested) (TMC 18.45.080). Wetland B does not meet the criteria for a Type 3 wetland because it is less than one thousand square feet in size, though it contains two wetland classes (TMC18.45.80.B.3). Thus, it is not regulated by the City of Tukwila and requires no standard wetland buffer. Southgate Creek, located offsite to the west, is considered to be a Type 2 Watercourse because it is perennial and has the potential to provide habitat for salmonoids (TMC 18A5.100). The standard buffer for Type 2 Watercourses is 100 feet. This buffer extends onto the west portion of the site. The buffer boundary for the stream is shown on Figure 3. The stream buffer does not extend as far east as Wetland A. The buffer setback for residential buildings is 10 feet from the buffer edge. Building plans must also show the 20- foot area beyond the buffer setback within which the potential impacts of development on the buffer will be reviewed. Project Impacts No regulated wetland areas will be filled as a result of this proposal. The bridge will span the width of the wetland so that no footings will be located within the wetland, but they will be located in the wetland buffer. The project proposal includes the reduction of the standard 50 -foot wetland buffer to 25 feet, a 3 -foot wide wood chip trail in the buffer, and a 3 -foot wide, approximately 10 -foot long pedestrian bridge spanning the wetland swale (Figure 3). Existing vegetation in the outer 25 feet (east side only) of the 50 -foot buffer will be cleared for the development. This outer buffer area has limited habitat functions and is dominated by Himalayan blackberry. A few young trees may also be cleared in this area but none of these trees are 10 inches dbh (diameter at breast height) or more in size. The total area of buffer reduction is approximately 2,620 square feet. The 25- foot wetland buffer east of the wetland boundary and the wetland and stream buffer areas on the west portion of the property will be cleared of Himalayan blackberry and other non - native invasive plant species and replanted with native vegetation under the enhancement plan. Since the 25 -foot buffer area east of the wetland is dominated by Himalayan blackberry, no impacts to the protected 25 -foot buffer are expected as a result of construction and the placement of permanent buildings within 20 feet of the building setback. Storm water runoff from the site is not expected to negatively affect the wetland or buffer functions. As you have described, several low impact development strategies are proposed to minimize the negative effects normally associated with storm water runoff from impervious surfaces. Pervious pavement will be used for the driveways and other internal roadways. Rainwater catchment systems will collect water from the metal roofs of some of the houses to provide irrigation water supply during the summer for landscaping. Other roof runoff will likely be dispersed using a level spreader system or some other similar functioning system before entering the wetland or wetland buffer. 2 Cooke Property October 16, 2007 Conceptual Mitigation Plan Mitigation sequencing: avoidance, minimization, and compensation have been followed in the preparation of this conceptual mitigation plan. Wetland impacts will be avoided and no high quality buffer areas will be affected by the proposal. Most of the vegetation to be cleared within the outer 25 -feet of the standard wetland buffer is non- native Himalayan blackberry. To compensate for reducing the wetland buffer to 25 feet the remaining wetland and stream buffer areas between the development and the wetland and between the wetland and the stream will be enhanced. In addition, the onsite wetland area will be enhanced to compensate for minor impacts from the pedestrian bridge and pathway located in buffer and wetland areas. Low impact development strategies will be used to control storm water runoff from the new development. Wetland and Buffer Enhancement The conceptual mitigation plans for this wetland and buffer enhancement are provided in Figures 4 and 5. The total area of wetland and buffer enhancement is estimated to be 16,580 square feet. This provides more than a 6:1 mitigation ratio for the buffer reduction proposed. TMC does not specify a mitigation ratio for compensation for buffer impacts. All wetland and buffer areas on the site will be enhanced by removing invasive plant species and replanting with native shrubs and trees. Dense stands of young red alder may be selectively thinned to allow remaining trees more space to grow to larger; no other native species will be removed in these areas. These trees will be replaced with a more diverse array of trees including quaking aspen, western red cedar, big -leaf maple, and vine maple. The enhancement planting is expected to result in a more diverse vegetation community that attracts a variety of native wildlife species, mainly birds in this urban setting. Split rail fencing will be placed along the north property boundary in order to prevent all terrain vehicles from entering the site. Sensitive area signs will be placed along the 25 -foot buffer boundary east of the wetland. Maintenance, Monitoring, and Contingency An aggressive weed management program will need to be followed in order for this buffer enhancement project to be successful. This may entail the use of cardboard and mulch following weed removal to keep the blackberry from re- establishing and to prevent erosion on the slope. Spot treatment using herbicide treatment may also be necessary for continued blackberry control. The maintenance, monitoring, and contingency plans will be provided in the final mitigation plan. Monitoring and maintenance are expected to occur for a period of five years following plant installation. Limitations Within the limitations of schedule, budget, seasonal constraints, and scope -of -work, we warrant that this study was conducted in accordance with generally accepted environmental science practices, including the technical guidelines and criteria in effect at the time this study was performed, as outlined in the Methods section. The results and conclusions of this report represent the authors' best professional judgment, based upon information provided by the project proponent in addition to that obtained during the course of this study. No other warranty, expressed or implied, is made. Attachments: Figures 1 through 5 Photos 1 through 6 3 Seattle Communityd€enten Rverton Park iSouthgate Park (PeaPatch / 1 ,/ Cooke Property � f )_ 57th4 SM7Park (Jose-0 oste.a.Martional Park, `� Qjij 1 , r f __1 FosteCourse IR Riverfront Palk Foste(etpCoursed q + q fi t% r \4, Renton !Fazelnut Parka eaTac Ike Bicentanrii'al Palk? SOURCE: City of Tukwila, 2005; King County, 2006 Figure 1 Vicinity Map Cooke Property Tukwila, Washington / WEST / zv2.o/' AREA WEST OF fe:::-:•:•:•::-:. • p 44:70 * • .:•:.:.:•:•:•.:.;.:.:.:.• _ " * * -:•:::::::::::::::::::::::::.:: . :.::.:::i:::::::::::::.:. .!)* ; : _ : . ::::.: ; „,, „, 0 103 0 * Amilleilliirri,D.)Loriti) Wetland Grass meadow Buffer Enhancement SCALE rota Sewall WatIond Consulting. Inc. 27110 111, SC ft tatin.m. 11111112 213-69-0313 firs II.1-852-4712 COOKE PROPERTY CONCEPTUAL MITIGATION PLAN JO No SHEET OF o regulate hydrology elevations rovlded in Landscape /Civil Plans) MlWMM M. DIAMETER AT LARGE END rravED GRADE • 2 9 ID SNAG Habitat features to be 20' length (min.) and IT d (min) Preferred species Red Cedar iv/branches intact LARGE WOODY DEBRIS (TYP.) 16'length (min) ly dim( min.) Preferred species Red Cedar w/branches intact 03 IN DG)ETER VIRE LS Cr CONCRETE RIPE (TYPICAL) x42000 (TYPICAL) MORIZONTAD. LOG ',MISTED GRADE xD Cr CMCRETE TYPICAL) MADMAN (TYPICAL) — DD Dr DIAMETER WIRE ROPE (TYPICAL) CABLED STUMP O r ID IS so SCALE Pais SNAG TREE NOTE B/ DE MAPPEOVEEDBYSWIRAEIERUgS(RYf)TV REVISIONS 4444 COOKE PROERTY WETLAND CREATION GRADING PLAN Job NO AD1d Du*. 4 TED bT AW 000(4 by, Data: IHAG(OY SHEET IYd OF M! '11'1511 1 WEI =n= n =i -n_il- n= llclxll =li= tune. • CONIFEROUS TREE PLANTING DETAIL brsrarY- aawwrpolo 4” Nemo bar 0,4,pp NOT TO5GLE w 4Ywu.• oer. ewf wermwbY TOW iYYr SHRUB PLANTING DETAIL Nor 10211E I abt;Rdfs' (W4oe to rabbi) TREE PLANTING DETAIL 167 mit Meth er sad. well brhI r+Yea rcp NOT10SGla FOR YORE +aDAN1+M CONTACr YOUR COY LR =WY I1 WETLAND SIGN DETAIL Mg TO SG. PLAMOYGLJST ON1Y PLANT NAME SIZE SPACING TREES Q 22 Wabm RadCedr 2gat 55 alma No plata StaBES O 24 m • Oa nr 2g0 as show Q. 8 ReNosiorDogsvod oMwn Cann Nabors" ® 12 1Jam6sa 2ga ass awn • =nab 0 18 M1.4/1/hhny 2ga7 ashen (anima Inca's+ ® 12 Ilan Pa. 2gat aMJawa ONalatto CWaSdnnIs 12 Plat Mats* ' 2 g es alma al O 60 Naada Rasa 2gat tlstwn Rosa wawa © 23 Ragas aeny 2gaL SS sham O 29 RadElderdary 2g4L ashen Salta=moms+ O 51 �mdarard 2g4 ashen • N 2g41 tlaipwn O 21 54• 6440 a 2gat IN Maw Rasapbuwgs ® 39 5/.540P547, 2gat tlYUar AYysdlda mgrs Lm O 40 Lady Am rug Alvan FaiNtenans ® 18 + AmEtandwa' nr 2g5. Yen Seaf a 911000 0; - NOTES: - RANTING AREA3SNAIL BEOLEAREDOFNONNATIVE AYASNE SPECIES SUC H AS HSOAL AYAN BLACKBERRY. - ASK Y0JSTALLEDRANTS MIST SE FLAGGED WAUGH NSBLITYRA[N,WO NOTE SCSEAMPPROVIEDBY THE aLLE LIE GROW 0 75 .ID 45 a rONICI SCALE Iwo' Sewall Wetland Consulting, Inc. tan airy4 +w 4 EL L'aMaw, N non 453-09-0517 iv 553- 152-1154 4444 Job No AFnY arced by AW Orson by: AW owe bn — Oat: A490Ylro SHEET W$ OF w`! ®UTE PLAN Irk 9 MAR 31 2009' aD CO 1'410N;TY OI=VELOPI 4T § W H Ui W W U U z Z W F W A1.01 • gr9, bldg 6, NAN FLP A. , , 1 \ /171- • Id 5 SASEMBrt • .1. \ . \ 9 ./ '/L . 'II 1,111; /.._, ../ /:,.".'•"-' bldg 7 , /1 OASEVINT • 47. MAW R.St • .065 """^,•+---,_,__, '',., 7/ ' _ _ / / sl I r / , . bldg WIN RP • •815. NC@ BASEMIEN7 "eV MAIN hI7 • ..78. bldg 1 • •01' 16.8 RA • ,4151.112-1-17 eLl T E PARKING PLAN J 87, ■." r"' f r MAR 31 2009' COMMUNiTY DEVELOPMENT A1.02 i 13 8 e 0 UNREGULATED WETLAND B (227 SF) WETLAND A (906 SF) SOUTHGATE CREEK TYPE 2 STREAM \ Qlrd. 7; 0 \/JI TAX LOT 7340600965 NEST 2e7.o7;.. 50' WETLAND BUFFER N 9C eN' -60/' Adri.d.44 ..., end e' wood fang. u, rli.h a tech painted a MO NM 50' WETLAND BUFFER 100' STREAM BUFFER r- \ It EAST /'• / .0.00'00% /! '00% ;� 1 j /./ / \20// t p�TA% 107 82 mar South J 134th Street PROPERTY BOUNDARY CENTERLINE OF SWALE _ k6 „ X 22a ao NEST ,e. 72 LN..t Nw wood ,.,c. s „f— west Y J .net end nog ... fence 5' wood tone. 20' QUIET TITLE EASEMENT Centerline So. 134 Sl. edge o.041 *Woo, EXISTING RESIDENCE (TO BE DEMOLISHED) apron 0 SOURCE: BGee.t., land &••.Wa. 2007 Cooke Propene . C200127.0 Figure 2 Wetland Survey Tukwila Washington SOUTHGATE CREEK TYPE 2 STREAM WETLAND A (906 SF) FOOTBRIDGE/3' PATH UNREGULATED WETLAND B (227 SF) PROPOSED AREA OF REDUCTION -2,620 SF 50' WETLAND BUFFER i IL) & 19£Ssr - [CAL ) tt k lock \ EAST 090.007E I:' ki 41° SrArn-i- kkitall• \r _ South 134th Street (Unopened) 10' BUILDING SETBACK LOT 7340800982 m� la NEST kM rr asp t apron 50' WETLAND BUFFER 100' STREAM BUFFER T -�— 25' BUFFER PROPERTY BOUNDARY 20' QUIET TITLE EASEMENT BOUNDARY SOURCE: St ,noes, lard asnardrd, 2007 Coda Rowdy . 0208121.0 Figure 3 Wetland Buffer Impacts Tukwila, Washington I WETLAND AND BUFFER ENHANCEMENT AREA - 16,560 SF WETLAND A (9013 SF) FOOTBRIDGE/3' PATH UNREGULATED WETLAND B (227 SF) SPLIT -RAIL FENCE 50' STANDARD WETLAND BUFFER WEST >S• FE 1 `-' \ se 1- Aled CL 4 — L ROM SOUTHGATE CREEK ° TYPE 2 STREAM 50' WETLAND BUFFER 100' STREAM BUFFER oo - South 1,34th Street (Unopened) SENSITIVE AREAS SIGNAGE 10' BUILDING SETBACK 25' BUFFER 20' QUIET TITLE EASEMENT BOUNDARY PROPERTY BOUNDARY LEGEND 1.8Frc WETLAND AND BUFFER ENHANCEMENT AREA SOURCE: SchesnR Lad Stamina, 2007 Caolo Pwaaly. 0708127.0 Figure 4 Conceptual Mitigation Plan Tukwila, Washington PLANTING SCHEDULE SCIENTIFIC NAME WETLAND ENHANCMENT PLANTS Athyrium filix- femino Cornus stolortifero MaldS fusca Rubus spectobilis Thuja plicato BUFFER ENHANCEMENT PLANTS Acer circinotum Acer mdcrophyllum Corylus cornuto Physocorpus copitotus Populus tremuloides Ribes songuineum Rubus spectobilis Rosa gymnocorpo Symphoricorpos olbus Thuja plicate SCARIFY ROOTBALL AND SPREAD ROOTS CONSTRUCT Y WATERING BASIN* 1.5 E ROOTBALL DEPTH COMMON NAME OTY SIZE SPACING /NOTES Lady Fern Redtwig Dogwood Oregon Crabapple Solmonberry Western Red Cedar Vine Maple Big Leaf Maple Hazelnut Pacific Ninebork Ouoking Aspen Red - flowering Currant Solmonberry Baldhip Rose Snowberry Western Red Cedar •NOTE: ON SLOPES. CONSTRUCT WATERING BASIN ON DOENHILL SIDE OF PLANTING HOLE ONLY. I2% ROOTBALL DIAMETER TREE/SHRUB SLOPE PLANTING DETAIL SECTION NOT TO SCALE 3 LAYER OF MULCH IN 30" CIRCLE AROUND TREES 8 SHRUBS FINISH GRADE • BACKFILL WITH NATIVE TOPSOIL SCARIFY EDGES OF PLANTING HOLE TO ALLOW FOR ROOT PENETRATION COMPACT SOIL UNDER ROOTBALL X 1 GAL X 1 GAL X 5 GAL. X 1 GAL 1 GAL X 2 GAL % 1 GAL X 2 GAL. X 1 GAL. X 1 GAL X 1 GAL X 1 GAL. X 1 GAL. X 1 GAL. X 1 GAL. SCARIFY ROOTBALL AND SPREAD ROOTS 1.5 % ROOTBALL DEPTH 4' O.C. 3' O.C. 9' O.0 -- 9' O.C. 4' O.C. 4' 0.0 9' O.C. 4' O.0 4' O.C. 9' O.0 4' O. 4' O.0 4' O.0 4' O. 9' 0 C. TBALL DIAMETER SECTION TREEJSHRUB PLANTING DETAIL NOT TO SCALE NOTE NATIVE VEGETATION TO NDIMI (TN.) 911665 tam) TYROAL SWAM FOOT 'MCA ses TYPICAL PLANTING 0?PO$T011 W A 1.235 MUMS MOT AKA TO OOmif W • MEIN AND 50 MOM PLANT TRE:O AND 906,05 W GIMPS CP 3. 5, 7. MID 11 01 A NATUR1W9OC PATTERN, POW, uo• Mp CAI SPAM* PATER! AGE NOT OE9Nm. TYPICAL WETLAND BUFFER ENHANCEMENT PLANTING DETAIL NOT TO SCALE 3" LATER OF MULCH IN 30' CIRCLE AROUND TREES & SHRUBS- KEEP MULCH AWAY FROM STEMS CONSTRUCT 3" WATERING BASIN FINISH GRADE BACKFILL 10TH NATIVE TOPSOIL 3' -6'. TYP. SCARIFY EDGES OF PLANTING HOLE TO ALLOW FOR ROOT PENETRATION COMPACT SOIL UNDER ROOTBALL 5' 6X6 SPLIT CEDAR POST. NOTCHED TO HOLD RAILS ENSITIVE AREA SIGN SPLIT CEDAR RAIL 8' DIA CEDAR POSTS e'CRUSHED ROCK. TIP. I4 -18 FI FVATGN TYP. SPLIT RAIL FENCE DETAIL. NOT TO SCALE CONCRETE FOOTING. TYP. SLOPE TOP TO DRAIN. SOURCE: Sem:4 W LOIN Ru.4FN0, 3007 Cobb RopOM. 0700137.5 Figure 6 Conceptual Mitigation Plan -Notes Tukwila, Washington • • • Lb � So w /,Q 1. CITY OF TUKWILA Department of Community Development 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431 -3670 FAX (206) 431 -3665 E -mail: tukplan(aci.tukwila.wa.us AFFIDAVIT OF OWNERSHIP AND HOLD HARMLESS PERMISSION TO ENTER PROPERTY RECEIVED MAR 31 2009 COMMUNITY DEVELOPMENT STATE OF WASHINGTON ss COUNTY OF KING The undersigned being duly sworn and upon oath states as follows: 1. I am the current owner of the property which is the subject of this application. 2. All statements contained in the applications have been prepared by me or my agents and are true and correct to the best of my knowledge. 3. The application is being submitted with my knowledge and consent. 4. Owner grants the City, its employees, agents, engineers, contractors or other representatives the right to enter upon Owner's real property, located at 13325 Macadam Road S. Tukwila WA 98168 for the purpose of application review, for the limited time necessary to complete that purpose. 5. Owner agrees to hold the City harmless for any loss or damage to persons or property occurring on the private property during the City's entry upon the property, unless the loss or damage is the result of the sole negligence of the City. 6. Non - responsiveness to a City information request for ninety (90) or more days, shall be cause to cancel the application(s) without refund of fees. /� EXECUTED at g _(city), W / " / (state), on li42 Z� , 2009 _ Print Name TODD SMITH Address PO Box 97193, Tacoma WA 98497 Phone Number 253- 691 -8. 91 i �7 Signature On this day personally appeared before me to me known to be the individual who executed the foregoing instrument and acknowledged that he /she signed the same as his/her voluntary act and deed for the uses and purposes mentioned therein. SUBSCRIBED AND SWORN TO BEFORE ME ON THIS /- �J DAY OF �'CZt 20 0 T 4. — d Notary Public State of Washington ANDREA .M ODD My Appointment Expires Aug 1S, 2012 NOTARY • Ij L!C to and for the State of Washington residing at l_a k.Pu �-rs 6f My Commission expires on _ P //S �D 2- or." iE) MAR 31 2009' COMMUNiTi CITY OF TUKWI-LALOP' Department of Community Development 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431 -3670 FAX (206) 431 -3665 E -mail: tukplan@ci.tukwila.wa.us bcaLSA of SPECIAL PERMISSION DIRECTOR APPLICATION FOR STAFF USE ONLY .Permits Plus Type: P-SP Planner: an r; , Gc,Q, r- File Number: L-bq - 0 V'L Application Complete (Date: ) Project File Number: WECIFT 023' .. Application Incomplete (Date: ) Other File Numbers: € ©' —001 xLo33 , —c)L'S` t_O°I -O NAME OF PROJECT/DEVELOPMENT: C v ee4-) %'[' % • / >do- S LOCATION OF PROJECT/DEVELOPMENT: Give street address or, if vacant, indicate lot(s), block and subdivision, access street, and nearest intersection. J 3 3.2 4- S . LIST ALL TAX LOT NUMBERS this information may be found on your tax statement). *7 3 0600n92. $ *1 o6o0 98'3 DEVELOPMENT COORDINATOR : The individual who: • has decision making authority on behalf of the owner /applicant in meetings with City staff, • has full responsibility for identifying and satisfying all relevant and sometimes overlapping development standards, and • is the primary contact with the City to whom all notices and reports will be sent. Name: / JI 5,7 q4 Address: P o boo 9 7/q3 7-4-64-"--& W 8 % Il q 7 Phone: 2 13— 6.1.1q/ i ' 81 t / FAX: 2 S 3 — 6-8/ — 390 E- mail: CU4k CD/ i e5 & ' C >71 Signature: i►di . af111 Date: f pv-vy •.■ • CITY OF TUKWILA Department of Community Development ' 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431-3670 FAX (206) 431-3665 E-mail: tukplanQci.tukwila.wa.us AFFIDAVIT OF OWNERSHIP AND HOLD HARMLESS • PERMISSION TO ENTER PROPERTY STATE OF WASHINGTON ss COUNTY OF KING The undersigned being duly sworn and upon oath states as follows: 1. 1 am the current owner of the property which is the subject of this application. 2. All statements contained in the applications have been prepared by me or my agents and are true and correct to the best of my knowledge. 3. The application is being submitted with my knowledge and consent. 4. Owner grants the City, its employees, agents, engineers, contractors or other representatives the right to enter upon Owner's real property, located at for the purpose of application review, for the limited time necessary to complete that purpose. 5. Owner agrees to hold the City harm less for any loss or damage to persons or property occurring on the private property during the City's entry upon the property, unless the loss or damage is the resulf of the sole negligence of the City. 6. Non-responsiveness to a City information request fo r ninety (90) or more day s, shall be cause to cancel the application(s) without refund of fees. EXECUTED at (city), - (state), on ,20 Print Name Address Phone Number Signature On this day per sonally appeared before me to rn e known to be the individual who executed the for egoing instrument and acknowledged that he/she signed the sam e as his/her voluntary act and deed for the uses and purposes mentioned therein. SUBSCRIBED AND SWORN TO BEFORE ME ON THIS DAY OF 20 NOTARY PUBLIC in and for the State of Washington eliding at t Ny Commission expires on NW 7/4, SEC 15, TWP 23N, ROE 4E, W.M. CRITICAL AREA MITIGATION GRADING PLAN I 1 SCALE: 1" = 10' v u Tc V ran C rri 5 1 rO � .0' 7 Z a 0244, nee ak..R o.,xm WETLAND STORAGE VOLUME 0154 X.W (R) RAVAGE AREA (SO 510544+745 WLWE (0) low IOLNNE (an) 52 00 058 51.50 2757 i,111 .3103 51.00 2236 D31 1,662 5030 1.511 626 915 5066 991 ND 191 150 101 555(20ED STORAGE uYUYE V0 ADOMNAL 97E RUNOFF " 635 Cr. (I00 7EAq 24 HOUR STORY E2YT A1TER A6N'BTION 61 RAN GARDENS) PROWLED STORAGE VOL4M 1,162 CV. RAIN GARDEN TABLE STORAGE 90LM (GE) 20 2 20 2 20 2 20 2 :s:oElm PROJECT YIANACI-Pr REV 1,4062 .12 PROJECT CNONC£R: E SUMO. Sr OCYGrCR: 62112106 6260006 PLO DATE. C 08 -068 OP-0 1 1 or I • 7 coos-1 • 30 • / 197.AX • 5 MCVA/ • /2 MAN • 0 P0,31 .3 ACERC • /0 20/ • /7 • /4 MOLYM • 5 13,6,-/ • 20 /22/5 • 9 MAT • /4 RIB , *IAN • 3ALM • 24 SOURS 00760.5 Casact mammas/ orb. • /4 5SOS - 00 104c1/4 // AIMM -24000040 • 4t 65,4 32 5,6mp • 1 100000500 • / 77151 -So /4(109 - /A RIB • If $4261m snwe =As awl:age ezale Scr• 44640444 444717 /254561p . CAR. 50 4.) as AMAX lignEirgMAdiVIATIVIUNg VMS • ,PTOArtVpip 4.111111111111.111411 -1*--111111%11421..,. Ileatelk tr‘billitilbfr:C11"1"1" 1111N-AVE', ‘011,11b114 tt 0, --mre .4%4011PWWWW A.r. . . S., 4 1 i datillillilliali '"IINNIFIffiff IV ow, Frammoz....,...,..... *it Are,iii'lpF, tr-,..■-millrt.,.. .710 uaq,.....k..... .., .....h • *MEVA /' • ;Aft/ ..-i-.'* msi , 7 250554 OP'V 'Arms/ 441 ftIrrIgM crThsl SECTION AT WIER .=.1111Z-M -1=311111322-0_,MI 1111111111114 glITIG COON CONCEPT ANO C.O•LS gat un: mum: pl.... inagn iajwy. tu he starml an ule mnre Min 14 haws will be heeled tote inamil median Pmeaunnowy mamma Mall be Melte enswa Mant minerialsdn 1.1 MITIGATION CONCEPT no dry m before plump. Rm. art to . loosened pace in ilvealiatiosa Immediandy inmlbnen t. mammon planng aro MI be mum. la acrid opillary arm. if3Sd3.Id3ffmth ., Iberefore, for rePteine he 1MM meta. hilret down to 15-311 the p3if • ill Mance ihe remaining pnrinin ihe buffer wilh 3e3. 3 2.7 T. ecintruwe vtaify 311 31311 mama, Me mar.* ahem an dm Mariam Man. end Me Om schedule. 33. 3317333 13 31.34 nem and M.. In ...inc. Me preject will create adMienal wo.. Peng dye *mere woland .unden IMM1n1111141 111M1331 WM M Occedmn °cm ammi. M Pa M. he gemmed by amin. sodomy of M developmerna run pad. wader thromb the ammo ma Ilumels. wetland creme,. oo imease flond mm. memo. within the Min and pmide imprimannu Mer qua... The Migadun he 33 PLANT ANII HABITAT MATERIAL INSTALLATION meowed fur • poiol at 5 yews nem Me ...and creminn ono is common/ v. all dm Mamas. Maw features to imaged. Sewall W.Mnd Canaan, Inc him 1,1.34 aim 3.134 hita roamed. following Am. with yawed m We mMennen 3.31 All Mem and 1* mmerish men . impacted prim m yerM emfarinarm of the .43 331 e *4 *1.1.!. ocluding iacc gm.. end Man., Any plan or laMitsd maaisly Maw. umnWeelory MA Ira rtjtlIal. 33 .2 All Mant truMiela daliaercd and empiad Anuld tic MOM inamehmely. follawing buollsion t. Maim Pam. depimd nu Me pm Moo matemalmo pas. within 24 Pura MI he beelMin m ono y, Plant nmerMe mired una. eandinam win M siameamw.MY er ma.", Wm. MI. Premmed M in mama M mai .11M. drying no berm, ne a ger plamin, 3.3.4 All Maraing pits will he aim. with ...eel Ude, and will . mad ail on Me mitigation plan and filled with pi seds 1.11 CONSIRTWITON SEQUENCE appeared by the Osenas rowe nib me domnined to 7. unacceoehlehy to Own, NaIng3* p. aids MI mad. will Ca Orme mulch o mayalead. 344 feeMicera .used MI. the moan. area. la buffer arm noly. 73 t3.3.4lpl43 ferMzer ta all Mama p.333 ....Med by manurmucer. Fertilizer§ are slimed ...law grade in the Matting pm in M Pao mac No .wage sludge 11.M. CSIewre nr Yiniwas, in =limn. Ma See Mon IPT.L Cm. 13.. hiltigoim Plan . Mamma Pho preimed. Ken Lime Archon. See Sheet OPMCMol Mulanan Mradmg Pm nomad by 1Te 0431333 1113.3* Ile MITIGATION GC... 1.21 12731 ■pporiorecly Etcw I.2.2 Enhmee weliod buffer wall racing trees and MM. Tbs causnweim ocmenee MP prom will be implenteuted ea tallowy 2 1 Prememuctim meam 2 2 Comm.. nuking 23 Canso-mire toping and maim morel 2 4 Clearing and Cant 2 Consnonim ar Weir Midge 2.31eabilintion nOylnigatian Am 2 7 Mani 'mama.... 2.3 Cansensetion inumaioa AgeM,Pfamal 33 6 MI conmenced plant matertals MI be mimed Eon elleir mamma earday m rearm damp: 3137 piLmi and lo Plms ream ed Mu commo . Mantel unmanly 33 7 AU Mos placed ma shown an Me mweved mmation plart Me final mollanon •me, from Me appron ed Inhigma ennumee will prmide a mondu...le ntylar astu. al. Mulled coMiens. *11 303 male.. Ragged by monme, 2.11 Mk fence romml 2.12 Maim comploino 33 1,11 malMrcen • m Mad m M maigmaa Mu. 111 ticalk.. boa m sn.nmnms MM. Rom. tree acalung arel guy wires fron all trees Whn T. P. Mon oc. Anmaem ma mon. LI P.3.4..8173.7 M373.3 wire and roe solua from. A gemanstrurti. meeting win be beld nomine price mumeneemeilt ef manna. in include Owneh bielminobe anarchy.. • Omer and Me Coy. M. nmenced plara specifionms MI be reviewed re maim M,M1 P.m malcol Mmom at,. 3.4 PLANTING.ATFIERMLE.LND WARRANTY amocum domm...pecificaims, mcannmenutl seam.. and inniMaim The Mi. aldoning and grading et the mitigation arm will . marked in the Mel by licensed p33le33...11* woe, Prm 73 ennummeemcol mo+331.no Cmoruer.• farm., Ea* Teal. 307.3333 10 31.., adjs.. to Mc mitimoun mi.m. including towing mil range aroma P.M • ill . Eamon mend fag MI ream mend nutignuan remand Mann, md ...maw me warMem. 7...4 Clewing A Gmillne Cloning and ending include emcialou of We wadand ar.13.E.1 spos ...and mom. dam m Jae payling Frac.. by Pe BMA. Ormip. addah.. potion of Me mining amid are 33113 e maimed re hace of gredes and in re. reed canary ma &Menu PM crotion Am will he ma exavved se., sod win imparted to My{ rhe wetland arca to grade. 1333 331431 comer, mho rW mean wale.. bd. hew ham dmigned Mcs nua WAMPTY m Ron 1.1.1.11MWM ova amen al. enitiptica .i/1 mininuan mammon poo87 for wok melne • mantoMannuir arm. Work >MAI od/ nem.. omalemsgMaursam. manna. Ose coutnaMen al. wedesel am MO mline aim mammon ...pima mem, m M nomination equipment will likely *0 neavetnnal, tackhon. and nve. fur hauling l• Camera. of Welr/BrIage 0....o3lllflI331,n*l.4d*4.drn,l.th.d.78.3 eam no... The emstructios WM weir sbauld be mandmed at Me • al he Arland . 153 A fillwiriter instal.an schedule P.* 10 .47.0 IMMI *Med be Iimer rms of am pames. WM. mallatien sem dumg 11. Ape, or sooner March Md. • 0o. lail the plowing. will be ininMed Mb temporary autmarie inipuian symenathroughoo the summer mint. 18f0 0..0333;37p31 00 em pm. TM in head mange 133 3. onire glandes area. Tfie Immo. caumllo wig 3, Me31111 to minimum nifillam ilYi mime. m ay day until PE 3.333.7 3.77407 Mope17 raintal mama M Mem maleror Mae Mamma Mamma be mered Mee a day Mr Mon 115 i enuAutes Mr. PM... 14 AP disnabed meamill 3. 87 re see.d wah num. mem. en We glans as soon Mining:ono area pad, emplete. The med mux lxmlinsted and pars covasere MOM. Id .ra ia..aaaai...6 emceed ands will 0. 3333331 •a 2,774 maim mural maw. and M mamma will notify Me Owner in Mang eif aleermiye mohad usel 343 IsIsilt .1 wen, •■■ ries”... • te* heat.. raw Mr fe• • pal err me yew' 467 lusatas • arrepmer. no .4113318 *443 '7 Wad.. unbradthy pa material, my Me eppemin1 glam 31 moaficalm. 3, SITE CIMENTIONS 1ST The inmner mll mordinor Pe Owner and Mama, biologist Mr commie. Median, 3.5 2 Landscape marallatim Yam eller Innl*a mamma wading cenimetim. 133 fi..ne," mollAWin Mum aponcol amiss.= gamy eMan. umalLs renombIe to maimed milammem a. aim beam. MI hmmemmdc mc M 3.5 4 Ager Menne and mob. is couples us Me irdimeinn me. exposed an. be seeded ar nag. Orange mamma. Mee MI 3. 30.31 ma dye natigatim area te prohibit equipmeo and poneneMin.Migatian area 2.3 Senblarmko Melge.P. Area 11. All lam mo.Y. • M able MI. plarding deoila Saila reem Merging holes nil1 be mewl and marched mm 43W,dS.l7.,lIIl.333.I.,.d.011110.4300m.3p.41,1,p.3440.75*13g1.dfl Orange townsman fencing and. gaii roingeinmr. ram camel knee will placed aremd the mitigation anea. 4.1o. Ana., 'be Nang... 4.4 .111 ow/ ...ad. e prime d ...won .6 3. 333133061333C1 PROGRAM 2.7 Plam Maerlal ImallMea ETTRODUCTION phan restavd bc Maned by knatd m detail end Cnontructian Mem MiliaMios Plan apwirm ronarial.W. me.es. a.m. and lemanan al Meal WM mulled_ The ...maim MI tamed ar mermeed hydramded arms dmurbed ames the 'my... •:14.1.1b Dv ....no mek during Me riming meow Ilpen eampletim aft. planting. Pe maim ann. P.M will be rewired a repaired. elm ...inns 33*0d,l.7,32333*171.133*44314.3.p771311.74410!lh.I31&,3133.Vl.4dll.C3.1p13334*331310 Psis mannelanee penman. MO 4.. poeet maw Mow. M 33 mdm1MP Mmes. do Maim 13 133 maw* peried °rail the Man.& .7 Mem art rm. 213 nuieleallee eanokle che 1.11 Consmelea lamas *111 entlined 11343* enmplelinn M the Owner, 0.4.1133 Mll conduct an inapectinn in met,. pmper implemereetian et M Plan. Any mamas, mbistaulana o met. wal Mourned in a.m.. Li, lama et mamba imminence will . sails. P.. Pa 4.3 MAINTENANCE WORE MMPE ave1 phou amain. Mala sice. mulch mouni pits. and tree slaking. Po. camplearm at Mao., eastallaties re morals mo sigaMematy trano.Mitigariaa flan. Me comonemllsationt repanhseMe Mem. te rhe Owner 1.• Ami micepoince et rhe Munn* by MO.-no, bielogisa a lem will be prepared na the City mutating wpm. of Me ins011anon. Is No *mum of Maims in Mc miataino 66a slava laaa Nn placement nr or awn.* in We migrtim mem am noed the MM. desmla The menitams proem, yin bepti am yea Me alma nen ?ATM canna. far 3 years The subseamern maniumg insramians will he amine. in mmardance wigs Me mom. NI miming Promarn. Nn placement nr areas clumum. Lod... dela. Um memo. Mau mater011 in the minganot am_ 4.1.1 The primary pals mniginim plan me te romp cleaM area with mice Mane commun., .piolly Mad mimed unikelminal uplawki and MR shipw wmaglislat. gag. nonsul busdympeng methohi mea inchtd, a No mmang nr Miming at grmad cam ar yegomm enhe magnum men Ell RA Enna Realm. 4.1.2 Wok to be whaled mead sise Denim mural fenenie apace.. wale rniciem inn me • ill remain in Mare mil AI areas at... Mdse. mil isation am hat eMen e. Remove all liner nicluMe paper. Mune. Pones. comm..3 debn, mil Mims, ea 211 Pr... Cameo. If al. tbc rmel year Pm. 51 of owinitoring. M has yatiMed MM.., isodyembi OnaM, 0774331 Mgpreme a !Mom ehe no Foramina eaew n P.- SA PITTIGATION 1NST ALLATION 3.1 SITE PREPARATION 11.1 The landmipe Comma MR limana atm malitiou rif saber* Mar to Miamian deny mpaim imagarim no, 7Te lam, Comore wig Orem the Owner nf any dim/gene. Imamate mowed memo; ...mat aml Mating coiditima 3.1.2 T. Genoa, Comma will Rag Me Mi. arch:mine wieh mum... Mains.. will Mow.. Ming mosuuctian. camel features ur amostion will be MEM. beymd the agog. damns, 3.13 T. ImMenne Carmelo win h.. wida bleckbary mimes. Weed debria. . dimmed 01.1.11.. 3.1 PLANT MATERIALS 111 All Mao be as apaMcd plara wbedule. 3133 Yip...Mons .e WM. Mum and iMmotio. are memble insolluices. Only worm bausid aced planis will be seceptable. 3.2.1 All plard malerials MI maim to M mentwas end sine reouremema el ANSI 2.60.1 'American MM. Nursery Stoel, All malerials .11. nazi.. 13* mrthwea, and preach, II. Pupa Masa Regim. Plan malerials will be wed Gam mike Ills. u cub.. or berlirn idiom. All Mao amocrilds he gram (mown. wick Mess aftleme 3.2.2.111mmer3 AI p.m materials ...monism a. Wiled harlapped. Me rem Maim, he subjen to mem.. AR P mcm,mmle Mgo than nvn 12i weeka MI be ogamed um end Med by Me maramr m additional eau to dle owner. Pl77.3II374f0I.4 on the am linger Man face week.. Masa mmecialf tonpararily Mod will be ..1011. inspection and ammo! 4713. 37 i75ll 3.13.Miminis immio plsen siaa moan muid adwaincd in writinmo M Omer. Om, RM.& an3OPPrmed da,113 of Taw. t Mom all blackberry mime and smehlamairmid. Me Miamian eon AO del3314 is la . rimmed non ake and disposed an app.. WWII, Manually cool alma MAIM Mon 11. Repair Mt sorne nommen, fencing and amp...Mel AL 3 WM 17 be eimmletol ea mud 4.73 Mina, Areal conoining Mack., Mat. mem. hand culling to Meek., If me of habicido Mominel. a PM be :Am. in Tug Mr permann prim m use. Only otEned pommel Ma Ye allowed m Imbindes nm criliol ma. j. Replambrad or failed p4M Rephwerma Mar, are m be of sane gm. aim a himum ma Marning.. Pboings are m be inualled during ihe dem periM. , Pomo me soli. and gm wires bon all mem. me ye.. 42 NIALATENANCE SCRIM. Omo conduct items Med in the Mainumanee Mope In h. arm. AMmonal wok may be required pa 11. NM MM. Reyna end as mom ed Pe Coy. Add... wok my include rem. al GI. greases amend .ch AIM acal me. 43 WATERING RECIEIREMENT. 431 If plantings ore agled peried 334.47384 0. wintir moth. illnahn 084111 8.773 IM 1 winning is no remind odd drpsummer samba 33.11( Meta, are inaollol dunes M summer nu* March dwougb Ocrobar MO Mummery 4533313.3 .311* will be rmuired. Tbe Mammy Migaaan &yam may Ix roman! Nee the third yew providing the Omtings ere m.blinhed miirnmed emite 433 Inigation will minima rim ininetirm Memel Onaher 10,34644.77. Mae If and 00. 10 tar ans sulmoseo 3e3r 103.17333, 011 43 4 IMenaun will Indy h wed us help caMM mairrials anMi nee m smplemo ern. addiiimal hydrology in Me MigMln M3Mian we. fia Me Mi... ma win tat. Wm dec Minng mon in Mitr. and no m wetland, mind nr mama 4.4 CLOSEOIR Or FIVE TEAR ..11.1111,411PROGRAIR molMim 3110enneWn'30 777374e3 .e0 ...am 1 M. rhe nunaMem yea by the C... maintematee Mau mylio MP. reduced to oho. mum. a( kner and Men nom. el ...as imeds and undesirable Manny and remit at yarn.] arm AA MONITORE, PROGRAM ,1 SAMPLING NIET1401101.01, The maigmun arm w . moramed mes • Y.. year mind. Manilaring ill be eandmed Mile the kechnigma and prawdoo dmaihm1 belamo paanlify mem:1mM mel ernerib .3 703 =aerial. A moo:ming Mall Waned following orb mmitneing ,ean. MI demi. end way, uana al the Minor.... ma. tho Me. woe,. Ike vest.. ma.... mains Mimeo.. m MM. camecial m deem. the lindas mad yips af the inseallanney M Manted morial in Me miliganen area vo a be mamma enang eacb monitoring M Mel et wraMI at. Palatka. ,113 Hyarelogy Ilyamlagy mem.. Md. the Mum..., mum ..tmetnee Mt. 1241111n *3 3. sol news Mum We tap aim wan no mamma or Myer as rem. rem.. Sal STANDARDS Or SECCESS L mem et Pa mom77 nem, sall he hm. man MOM wry,. fia ...et, yew I a NOM mail. Ire all Mom eael atm.: Y. 2 Nee mere Man 101A moo er mama. mac .ren. nnitgallan sm an year 1. 3 Mermen indwin enanan area n.rmi av env pewill# nuelg LIS An, 1. 017% *14317213730334 A Velum, reiricenonmmai mes ame inctmled as weepale cowman of il. mammon. To will no he memo, Iowa. the 111.4 sucem requiem... CONTINGENT. PLAN A comes, Om can be toplernenied mem, unnerney Mans on irMide regoilog. PIM ;MM., ems. 31 4. mmenng 78715 .4874 00 asa. Oe pe...mene amilanl. 2l. mn beMt meti a m3 ...maw, 3, insplmrsent all or pan It the moso.gc, Pm Careful maim Y. mar ma.. emattal to moms tbat pa aro. Mauld am at M m mem ih3 mema Mer.• PM mu be ...mod and ..pme Nycli Mans ere wepared case.M.case basis re mem 33 30,143 M.P.. Mmmmwm Replacing Al Mims hea us yandalmm amen. in nem., Replacing any Mara mam*. • mama game. moon. inne wah M aim mecie. ainuip *303 .443840 *3 42.373 Inrigaring Me ma anly neeman dmna W. nee., •, plants...ea 01 ....dry... a minimal uuraity of miler. R7..:3g thc mitipaum rah an mom- a pm mule .7.40333331 omineMagermuman imam Remmum aasla re undesirable Ms. Eon Ene rem.. ma as memory m 4 0 433138731 673343*. HORIZONTAL LOG SHRUB PLANTING DETAIL nv ALAI f . 6 Irta lopLal TREE PLANTING DETAIL 773.3333) ‘- 2 I/ 'ma 41. I for sae acal <Alma ow gag room. NOT TO SCALE SNAG FREE Aroadirara - ----------------------- ti= akeR44 *3415 CONIFEROUS TREE PLANTING DETAIL P1 NO, 30 ii-613 FOR YORE INFOILMATIIM CCW1.1":1777 OffIROWL4 (20814:111050 71AMSIGIV MOW Wp.Erolan2 XPLCV OM. • MIA cam, reZ rVg 7s6i, ArSiat= 4' tJ4- EC WETLAND SIGN DETAIL S.,■( AREA MITIGATION PLAN COMMUNITY DEVELOPMENT Aibir Sewall Wetland Consulang, Inc. 2760 Campos gay SE 12. Comp. RA 30032 253 Mg -0515 1. 243-444-033 Daati AW amehal 343. segena 09 SHEET 0-3 OF 1 NW 1/4, SEC 15, TWP 23N, RGE'4E, W.M. CRITICAL: AREA MITIGATION GRADING PLAN SCALE: 1" = 10' 0 5 10 20 I. z. REED CANARY GRASS NOTE ALL REED CANARY GRASS NIL BE DUG OUT AND REAMED TO A DEPTH OF 12-241 77I8 LOCA7IQV OF REED CANARY GRASS WLI. BE STAIXDD IN THE FIELD AT THE PRE-CONSTRUCTION 'MEETING - REFLECT 97E CONDITIONS AT THE TIME OF 1CA VA TIOV. 147. g.woutO Quc C.91Aiasi (yes:. LNt11 b , 4okun o{i si +E. Roc proper dlsposaN WETLAND STORAGE VOLUME ELEVATION (FT) SURFACE AREA (9) : BNCSDJEVTAL VOLUME (CO ' TOTAL VOLUME (CF) 5200 .x378 1.527 4,631 51.50 2.731 1.242 4105 31.00 2.236 927 - .. 1.862 50.50 1.512 626 925 50.00 992 - 299 299 49.50 204 - - - - • REQUIRED STORAGE VOLUME FOR ADDJDONAL SITE RUNOFF; - 6ss CF.. (100 NEAR. 24 HOUR STORM EVENT AFTER ABSORBTIOV - BY RAIN GARDENS) PROHOED STORAGE VOLUME ■ 1.862 CF NoSS.S TO 8 - INGW IN -E-Nt. 0:012-Acre 4= SPtc A (WW1- of- 'M'E Pub Mc.. Woe)IS y■. 02009 OE MEDIC GROUP RAIN GARDEN TABLE STORAGE 'VOLUME (I RD I 250 RD 2 m RD 3 151 RD 4 104 PG 5 225 RO 6 W a ;� BLUELINE SCALE: A3 NO= PROJECT MANAGER:. KEN AL LAUZEIL P PROJECT ENGINEER: BEEN T. AIIO01II94 (E DESIGNER: DO MLLE GABADON PLOT DATE 4/17/2010 9 S cc 0 y ti a 2 CRITICAL AREA MITIGATION GRADING PLAN COOKE CREEK MEADOWS 13325 MACADAM RD S PRELIMINARY CIVIL PLANS CITY OF TUKWILA WASHINGTON - ECEIVED MAR 19 2010' ogn=7. 08 -068 • GP -0 7 9NT 1 OF 1 4 /A 7F5 E»'STU•A' ALDER Lot 7-14.1,V 6 cswif2q 7z, RawvN (f/) • 7 Ce ski .30 RU11• / P4X • /2 A444. .5 3011774.476 020eA GSA' • /1 MNR 2 7T/OJ 4e 45#4 32 5yMP / Ace,a / 77/44/ -30 14 V8 MAN /O 6S// -/6RIB /7 4'J /v AZOS 3 'GAS 3 /.3/3 23 EcE6 Iir< 1 •- 4 , ,s p irtrWatal -ii J ,1-.-r.1.7 fa � =:mot • /4 SJ1MA • 40 SGR/P /8 aJ1AV4 /2 S'YMP • • 3 .4c8¢c • /8 • /7 I/0 • /4 F L`s' L4 • 3 T71uJ • /O ALB •3Oar • 14 RIB i p� 24 R/5 • IMO FiWM ( AI AiMErg — `I 1' WOW! Wit s7D sIAS awenleGe 2L6V', 52= 44iL 41144771 • S2 CAR So • 9* see ez/P 48 /3PRdx a 5444 11. -.444611M11311W4-7141741•1:-T 37AIIE Walt I �e 1 I 5 AO'. 1/�.. �3�� gzi�A_ /* aziestati s 4370 MIPTrilliatir �aen ,f%/h5•_ 81.84/. Seer sollegf er'WeR 50 •• Y 44GX.S1»%l6r �dC •- 80nrN4 op'✓.'/wefts/ 441 - SECTION AT WIER • 23 —OS MP S L.1/P /MIS ' SyAIl /6 411. • 716W *Aar • *PBTA • 20 COR • tumour Ateialgt# tit 4C..RNS Z4: q" tt. PLANT LIST H.. • / 7 MUJ . / PN)' MNR TREES Quantity Symbol Common Name SefeetnBo Name She 1 ACERM Asa mamapbylltm Btg/mfmopJ. ' I piton ono Mot lilt height 6 10 TNU3 Wmmo Rd Cedar Th far ph w° I gallon rat Mm I5-1r Might 9 POP , Poplsstremoloidm Qm4Lg rape 12-lr height mss . Igallon can, or bare toot if Nov. to Moth planting 6 • CAS Catam Rhaemepashlea 12- 1rbeightmtr bare root if Nov. to Matdt plamlog . 3 BET Paper Birch &tufapnptrgero l gallooagmm 15'lrhi 4 CORN Pacific Dogwood • Canton °adll . - 12 -Ir Wight mm. 1 gallon am, or bare root if Nov to Maroc planting B FTtAX Oregon A.b Proxima lafdl 12- Irhoight min 1 gallon m, or boo root if Not, to March plmdng SHRUBS Hambm A C.ryrm a.moa Common Name Scientific Name Sloe. 9 ACERC Vine Maple Aar chdnom. 12.1r bight min. I gallon tan, or bare mm If Nov. to Matt, phoning 4 PHYS Nine Bak Phyaaampm mpimhm 12 -Ir height met 1 pilau can. oe lane root If Nov to March planting 146 SYMP . Smwhetry Symphloemym alba • '. 12-tr Might min . tp0on cm, or .: bare root If Nov to Machplaoting' 10 0156 _ Gmeleria trasifarmis - O•obe ry 1 12.1r Might mm. 4, 1 pOm=Npr tee root IfNov. to MercA planting 3 poP' • ll f1 s01MP 6 3, 22 /PSE 2 .a>a 3H / Pmts 30.RCt63 3 tats. • e vo • 2 GORJV3 52 RUBP Tnunbteberry . __ .. Curanl k.bep o9 12-1E" height mm. ... 1giloo cm. co bee root if Nov. to Marc planting 86 RIB 4, 5 Ribeermtgaoo.m 12-Ir height mm 1 plIon rat, or bra toot if Nov. to Mar% . Martin M RUBS . Snhom betty • . _•__._ .. Ratan specopfn ..... 12 -tr Might min. I gallon my or ' bare rota ltNov. to March planting 12 CEd2f 4 .; side willow Sdis sbddaeab - 12-lr Might min.. nJ • l pan can, or • : ' bps toot if Nov. to Meth. - • . fig 6 ;'SAM . Rd elderbery Sa6iba®rocmmma . :.' 12-tr won .t. I piton mom hot root if Nov. to March planting .146 ' ROS Pafuhtose . Rompbmvp. .. - 12 -I1- n 1 piton Ca; or , ban mot if Nov. to Mail planting 35 • - 23 MYR VO Pam myrtle Evergreen butklebmry Ap.ia, odyamla Pmdalm cream 12-1r heght min. ' I piton am or - :. bare soot if Nov. to Match planting - I am ---66- -CORNS--,-,-' 6.��dopwwb. • gallon • — i 3 H Hambm A C.ryrm a.moa 32.1r seedling one pllogye bee. ':_.mot b Nov to Afa BOY . toga boykima Bgd6da mgiw Bare too teedlbtg at it me m tip Brae root seedling at lrocoftip Bare root telling ei 1r -1r oe tri Pp Named on stream hank, not in water AO A 33 C-42 •/vAIG . L� ' 4# 0.4.A0.' ,4, e PErA 48 JAS • /o: QLAi Si 2i sorare.& JSURVEY FLAGGING 2' LONG METAL FENCE POST ORANGE PLASTIC . CONSTR- H. K FENCING jOrtl 4r USE ZIP ASS�CHA - FENCING TO WIRE AND POSTS 14 GA STEEL WIRE 1.�— o00070• SQ== ,000006 �I 1.1=3 -.V 00c = D D J MOM MRS 5=1 =0 is 0.0 — I -Bf 00 00000 �I: . — 3- 0000000c 11. =.IIs ?11.- 11=11 =11- 11=11_ 11=117.11:.11: . - -11 _ I II 6 I MAX II 1I II II u NOTE: J FENCE WILL BE REMOVED. BY OTHERS UPON COMPLETION OF BUFFER PLANTING EXISTING SHRUB AND TREE PROTECTION DETAIL Au mum w51PINm1 par rowoBEOVen 6WILBG VOMEt jaiNDA CRITICAL AREA MITIGATION.°_ PLAN/ PLANTING PLAN in..- 1• -r September 1 200 CROUNDCOVERS 167 Common Name SelmWle N.m. Ste 0561 G.drhofa shallot, MAN 146 Otom Grape Mahmia repine 1 gallon tan 1 gallon can 115 • POLYM Stmrd fen Pobmkkmt mrnimt 44 44 AUU LUP IOtmitmiek Lupine J•i4wn0 JdlJdl° 1 piton ran 1 piton mar t gallon cm 'p LEGEND WETLAND E51FRGEN'IS and HERBS 243 CAR 22 JUNC'i RIeWth emir DMAMeafd rush Corm odr.N. /mma.emyamar 335 SCRIP “soSlendernM lmiaa muds Ban root seedling to 12" oc td p. Bare root emoting at 1r oe W sp. 371 SPRO PvMed rush Jmtd'i inyme ds 20 it)NCB. Skank cabbage 1. BM _®Friconma ••i ..One gam containers a I 8-24" arc ;i 12 52 IRIS Alaska Wild his .frOmmra Bare root seedling at Ir- tr xtrim. One gallon toeminas to 15-24" arc 16 BLEU PETA' Common mRe nob Amommit'pot ar* Palmate oobsfaot 44 CARX . Slender wetland sedge Is ARO.'.. Reedmanagam Pethrttiimbommr CassJmlooerp. Qlywtkeirrerdb -I Bare root smiting tit IT -1r on t i tip Bare mot seedling our- Iroetrim Rae roe a1r- Ir«taint Pmrom ...mimic lr -Ir eetliap San Tree hwida i... pvena5m -dies w -1 Taer.omb•aueawd.an:.epe ; e. 14.411P. emtmmmw -L Bwbnml: hmrl. Ira 3 lm per bail mamw -t. beP pvbNM.hmw -t. OWIBtaam F•wil• lee 3 asp p4mam.ea MI. boa pcpe,ilm0aw -1. Lim t o t: Odd.6ama Mtwle as 14 ParNMtbt 8mmboom of .Qe EXISTING 1REES; casting boa MI to roman, save end protect ' . • tree protxtion fence around the tree par deal - • ��. i w' EXISTING ALDER; Saplings less than 6" caliper to remain. alt *ammo EXI.4TINC.WEIIAND BOUNDARIES *� CREATED WETLAND BUFFER: 50 fen to the west and 25' to the east - UEE ERI,ACEMENT TABLE I '4 E .REEMO_VED �'- REQUIRED NIjAABER OF R P ACEMENT TREES Ti1REE 81 CALIPER ALDERS 6 :TREES (*ET CALIPER ALDER 2.TREES to 8• BROADLEAF TREES 4, 5 'i`6TAL 4 -rLees R£NMV19 12 -N1EW TREE3'sREQUIRED ... HYDROSESD MATERIALS A. Erosion Control, rough Bass lead etas: This area shown as 'Grass Seeded Meadow" 0 meant to provide seeded gran over existing ban soil and areas where invasive ivy and blenkberies have been removed. Existing trees and globs within this mea an to retrain and be protected with a temporary protection fete per detail. The meadow will be (rv4gb ■11t: Sere SPlGF1ca -noNS gAsool B. Mulch: For seeded area: 1500 to 2000 roods per acre. For seeded areas apply at 1500 pounds per acre C. Tackifer. 40 prods per a.w, . D. Weter. Ensure ono adequate supply of weer. Furnish all recaary hasp, equipment, attachments, and accessories for adequate winning of lawn area. V MULCH PATH; moms: 3' width, path shell be construed with 3" depth Sawdust Supply "play chIpsIgarn; Qlayts of biodegradable cardboard or burlap. ,m, 113 be appllas141 bperaoe. Appem..M pm.loe to Ow Clb awmmbn from IN end toms .t. .. Myna6eeebr.tpe.a.m al M.ea. onoIon•mpored An. Cllra1T° iMNep mm0taYm.°° I:Mo'- hlm0 sar.war 546.40%. Q • MAW MF.wmml-tb%' • rmuswamappmgd (NM, I rM.- en...n.- .e....a a.. or Room?. Fe.o.l -25% tree planting detail shrub planting detail critical area mitigation plan cooke creek meadows