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HomeMy WebLinkAboutPermit L92-0057 - LOWE LEROY - REASONABLE USE EXCEPTION SPECIAL PERMISSIONl92-0057 slade way and south 160th street leroy lowe ,,. John W. Rants, Mayor Department of Public Works September 9, 1992 *Mr. W. Paul Grant, .P.E. Vice President Shannon & Wilson P.O. Box 300303 Seattle, Washington 98103 Dear Mr. Grant: RE: Leroy Lowe Development Geo Evaluation Ross A. Earnst, P. E, Director RECEIVED SEP 1 0 1992 COMMUNITY DEVELOPMENT Thank you for the 41 Ave. S. study. Enclosed is a similar scope of work outline for a proposed plat. It is located on the hill west of I -5 and south of SR -518. The work includes reviewing several other studies, calculating and recommending the following: - what to do with existing runoff and with development runoff; - affects on the hillside and Slade Way of the development and determining existing stability; - suggestions of site development considering the wetland and our critical area sensitive area ordinance and - runoff cannot be increased The budgeted amount for this work is $7,500 and a draft report is requested for October 9. Could a contract be prepared using the enclosed City contract and work supplement? This is the work we discussed on the phone. We look forward to getting this underway. Please call me at 433 -0179 if more information would be Helpful. Sincerely, Ron Cameron, P.E. City Engineer RMC /kjp Enclosures CF: Jack Pace, Senior Planner Phil Fraser, Senior Engineer. File: Leroy Lowe Shortplat 6300 Southcenter Boulevard, Suite 1100 • Tukwila, Washington 98188 • Phone: (206) 433-0179 • Fax (206) 431-3665 • ;;,._ September 9, 1992 Leroy Lowe Shortplat Soils and Geo Evaluation Scope of Work Items 1. Review site, vicinity, and existing area soils and geo reports Cascade (3) for Leroy Lowe (City copy) GeoEngineers Valley View Estates (City copy) Dames & Moore Valley View Estates (City copy) Soils /Geo reports from 53 Ave S, S 160 St, and Crystal Springs (City copy) King County Soils information (as available) WSDOT 1 -5 or other S &W reports (as available) II. Provide professional opinion and recommendations 1. Identify existing stability of Slade Way 2. Recommendations for existing Slade Way - immediate actions to take - long term actions to take 3. Quantify Lowe development runoff amount of runoff: - existing drainage ( "normal" and storm maximums) - increased by dewatering ( "normal" and storm maximums) - impervious surface increase - what affects on the slope and hillside? - what affects on Slade Way? what seismic affects? 6. What is safety factor of Slade Way and the hillside and what affect could the development have on it? 7. What considerations should be made for dewatering the site relative to hillside? What recommendations are there for the dewatering runoff and impervious surface runoff to maximize stability and meet runoff'requirements? 8. The City cannot increase the drainage from the hill through the I -5 interchange drainage system. What measures and recommended action to control dewatering and impervious runoff should be made to approve the development to meet this condition? 9: Considering Tukwila's Critical Area Sensitive Area Ordinance: - can 5 lots be developed on this site? - what wetland mitigations could be suggested? City of Tukwila John W. Rants, Mayor Department of Community Development Rick Beeler, Director August 19, 1992 LeRoy Lowe P.O. Box 1241 Seattle, WA 98111 RE: L92 -0057, HILLCREST BLA, APRD . Dear Mr. Lowe, This letter follow up our meeting on August 5, 1992. As soon as Public Works complete the scope of work for the peer review and selects a consultant, I will pass on that information to you. Ron Cameron mention that the review would be completed by the second week in November. Under the Sensitive Area Ordinance, you can submit a new request for Reasonable Use Exception at any time. The criteria for approval would be same as the first request. I have asked Darren Wilson to look into your request as to the status of the refund for a'SEPA. If you should have any further questions, please feel free to call . or write. Sincerely, L J$ck Pace Senior Planner cc: Ron Cameron City Engineer 6300 Southcenter Boulevard, Suite #100 o Tukwila, Washington 98188 • (206) 431.3670 • Fax (206) 431.3665 IMO John W. Rants, Mayor Department of Community Development Rick Beeler, Director NOTICE OF DECISION August 2, 1992 LeRoy Lowe P.O. Box 1241 Seattle, WA 98111 RE: L92 -0057, Hillcrest BLA, APRD Special Permission 92 -3 This is to confirm that the Planning Commission denied the Reasonable Use Exception request as presented on July 30, 1992. The Planning Commission adopted the findings and conclusions of contained in the Staff Report dated July 23, 1992. The decision of the Planning Commission is not final until the appeal period has elapsed, which is ten calendar days after the above date of the decision. Appeals must be filed in writing to the City Clerk by 5:00 p.m. on the final day of the appeal period Where the final day of the appeal period falls on a weekend or holiday the appeal period will be extended to 5:00 p.m. on the next work day. If you should have any questions regarding this project please feel free to write or call. Sincerely, J$ck Pace Senior Planner 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 431-3665 LEROY C. LOWE A.I.A. ARCHITECT P.O. BOX 1241 SEATTLE. WASHINGTON 09111 WETLANDS: RECEIVED JUL 3 01992 COMMUNITY DEVELOPMENT Mr. Jack Pace Senior Planner City of Tukwila Hillcrest, BLA Dear Mr. Pace: July 27, 1992 The following is in response to your July 17, 1992 correspondence. Our position is the water seeps and underground aquifer must be interdicted and the site dewatered to preserve and protect the down slope property, Slade Way, and the utilities therein. Without exception, every Geotech engineer we have contacted has stated: The fundamental principal of slope stabilization is to dewater the hillside. We have provided you with extensive historical documen- tation of two (2) previous landslides occurring directly adjacent to this project site, "61 "/ "62" downhill and to the east. We also have made you aware of a 10" drop in Slade Way over recent months, as well as a 28" slippage /fracture just east of Slade Way and directly across from the Hillcrest site occurring some time in 1988 -89. The water seeps and wetlands must be tightlined into the storm sewer system. PEER REVIEW: PUBLIC FACILITIES Mr. Jack Pace - Page 2 July 27, 1992 The city staff has had the Geotech report since September of 1990. You have had ample time, nearly a year, to do a peer review. Even if you waited until you received the wetland study, you will have had over three months to have this work done. I contacted some geofirms and found that an 8 -week effort costing the city some $16,000 would be required for a peer review. Storm Water: The on -site storm water detention system was discussed several months ago with Phil Fraser. My engineer, Richard Stuth, has submitted a preliminary design. Water Line: Your contention that the existing water system provides limited capacity is incorrect. We provided you with a water pressure and flow diagram on January 23, 1991, that clearly states a flow of 2,763 gallons per minute at a sustained pressure of 130 P.S.I. (Pounds per Square Inch). This compares with another municipalities' requirements of 1,000 GPM (Gallons Per Minute) at a pressure of 30 P.S.I. (Pounds per Square Inch). Hillcrest water delivered 130 P.S.I. @ 2,763 GPM. Most municipalities require 30 P.S.I. @ 1,000 GPM. The water flow delivered is nearly three (3) times that which is required by most municipalities. You must be aware of the disposition of the water line since you were present during in -depth dicussion of this water line. Jay Gibson, of Highline Water District, had our site plan showing a detailed layout of this water line and Dick Stuth is preparing a plan /profile of same. There never has been a problem with water availability to this site. Your request for water and sewer letters of availability based on final lot configuration has not only been met, but we have submitted "as built" drawings of the sewer line and proposed water line as submitted to Highline Water District. The water and sewer availability letters were submitted to Phil Fraser on April 5, 1991. A water flow chart was • • REASONABLE USE EXCEPTION: PEER REVIEW: Mr. Jack Pace - Page 3 July 27, 1992 included and also was made a part of our formal B.L.A. application on September 9, 1991. Your contention that I have not met the uses and standards criteria because I have not mitigated the wetlands does not make any sense. We have contended from the beginning that the site must be dewatered for the preservation of public health, welfare and safety. Our geotech reports this site requires dewatering by installing a drainage system. The report goes on to identify the past occurrences of slides downhill from this site. Nowhere in your March 3, 1992 "Notice of Decision Conditions, Item #2 Geotechnical Study" do you mention a "peer review" requirement. You did, however, comment on the wetland study and that .once it was submitted there might be justification to use this section of the ordinance for a "reasonable use exception." I must point out that with a 25' setback, you will totally destroy this project. The financial impact of providing the City of Tukwila with a water main, fire loop /fire hydrants and street improvements, street curb and gutter, will require a minimum of five lots -- preferably six, total. Enclosed is our cost estimate for site development. The statement in my June 29, 1992 letter that the city waited six months to respond to my formal application is a fact. That this site does not appear on your wetlands inventory is also a fact. It was our contention that the water seeps on this site, travels some 150' and goes directly into the sewer are of small consequence when viewed with the matter of public safety and in light of the previous landslides directly across the street. Mr. A.J. Bredburg conducted a site visit and concluded, as have other design professionals, that the water on Mr. Jack Pace - Page 4 July 27, 1992 this site has in the past and is presently contributing to the slippage of Slade Way (see correspondence dated January 8, 1992). Tukwila Public Works Department has also identified the slippage of Slade Way. See your correspondence Phil Fraser, September 16, 1991, "(2) earth, d. - add: "Slippage of Slade Way has also occurred at least twice over past 10 years." Wetlands were identified on our September 6, 1991 site plan and Mr. Bredburg was called to the site for his review and comment. See Bredburg correspondence in your staff report dated March 17, 1992. Also Dennis Joule, P.E., Resco Engineering. "There can be no doubt in anyone's mind that Slade Way is threatened by a potential landslide downslope of your property if the present conditions are not corrected. Your property and that portion of Slade Way East of it are saturated by seeps. The saturated soil is very heavy and viscous and hence, at present, lead to a very unstable situation. Slade Way is presently serving as an earthen dam holding the heavy saturated soil in place. Slade Way was clearly not built or designed to withstand the potential lateral loads due to the upland saturated soils. The most elementary Geotechnical calculations would demonstrate that Slade Way is not stable within reasonable safety limits. "The other consideration is the presence of a wet- land on your property. While I am not a sensitive areas or wetlands expert, it is clear from Mr. Bredberg's report and my observations, that there are some wetlands on the property. It appears to me that there is clearly a question of balancing the stability of Slade Way and the utilities in it along with the corresponding public health and safety against the value of the wetland. Mr. Jack Pace - Page 5 July 27, 1992 "It would seem obvious to me that the logical and most expedient solution to the Slade Way stability problem would be the "controlled responsible" development of your property. This would include street frontage, and storm drain improvements to Slade Way along with on -site drainage, dewatering and stability measures that would assure stability over the entire affected area." Your reference to the several options presented to me really left me with no options. I refer you to the Cascade Geotech report which states this site must be dewatered before any construction can begin. You refuse to allow me to dewater the site, therefore you have effected a "complete taking" of the entire site and therefore I am applying for a reasonable use exception as provided for under the S.A.O., Section 18.45.115 18.45.115 Reasonable Use Exception 1. If application of this chapter would deny all reasonable use of the property containing wetlands, water courses or their buffers, the property owner or the proponent of a develop- ment proposal may apply for a reasonable use exception. �� �� Very truly yours, Leroy C. Lowe, A.I. A.I.K. Arc Enclosures LCL:mgh cc: Planning Commission Rick Beeler John McFarland • CASCADE GEOTECHNICAL INC. 12016 115TH AVENUE N.E., BLDG. H (206) 821 -5080 KIRKLAND, WASHINGTON 98034 FAX: (206) 820.6953 July 27, 1992 Job No. 9005 -13G Leroy C. Lowe, AIA P.O. Box 1241 Seattle, Washington 98111 Reference: Supplemental Letter Hillcrest Tukwila, Washington Dear Mr. Lowe: As indicated in our proposal of yesterday, we have completed the work as discussed. This involved a visit to the site, a review of the documentation you provided to us, an evaluation of the situation and preparation of this letter /report. BACKGROUND We prepared three previous reports for this project. These include a preliminary geotechnical investigation dated May 30, 1990 and a report dated August 27, 1990 and a plan review, April 24, 1991. We also understand that there have been some changes in the proposed platting of the site. A number of concerns have been expressed since these reports were made regarding the dewatering of the hillside in that this would possibly destroy the "wetlands" now found in the area. There has also been discussion of continuing movement in Slade Way and in a landslide downslope from the site on the other side of Slade Way. RECEIVED JUL 3 0 1992 COMMUNITY DEVELOPMENT 4200 MERIDIAN, SUITE 216 (206) 647 -8588 BELLINGHAM, WASHINGTON 98226 FAX: (206) 671 -4329 July 27, 1992 CAL Z.ADE GEOTECHNICAL--.NC. CONCLUSIONS Job No. 9005 -13G From our careful review of the documents which we were provided, we have concluded the following: • The findings and conclusions in our earlier reports remain valid and the conclusions in the other engineering reports we reviewed appear to be consistent with the results of our work. • In the "Conclusions" section of our August 27, 1990 report we state "it is our conclusion that the site is suitable for the proposed development if a deep seated foundation is used for support of the building and very extensive drainage in installed..." • In the "Recommendations" section in the same report we make the following statement: "the lower, eastern portion of this site is extremely wet with soft organic soils noted at the surface. Working in this area will require careful and cautious techniques to avoid significant additional costs from disturbed soils. We recommend that drainage be installed prior to any site work. Detailed recommendations for drainage are discussed below." • Nothing in our review indicates that we should change these recommendations or conclusions. In our professional opinion it is unwise and possibly unsafe to develop any portion of this site without drainage work. • It appears from our review of the wetland study that this type of extensive drainage work would significantly change the character of the wetlands at the site. • From the above review it appears that the denial of permission to provide drainage on this property would eliminate any realistic possibility of development of this site. CAL .:ADE GEOTECHNICALC1IC. July 27, 1992 Job No. 9005 -13G We trust that this provides the information you need. Sincerely, eorge E. Lamb, President GEL:pg = %;PIRf;,... 11- 21 -Y.. 0 1 m z w LEROY C. LOWE A.I.A. ARCHITECT O. •OII 11141 •KATTLt. WA•NINOTON 0•111 RECEIVED JUL 3 01992 COMMUNITY DEVELOPMENT (14114 • t'1,1414. DARREN WILSON ASSISTANT PLANNER 6200 SOUTHCENTER BLVD. Of/ MNEEEMEO FEB 18 1992 CITY OF TUKWILA • PLANNING DEPT. tIILLCZN DEAR MR. WILSON ; FEB. 18, 1992 RESPONDING TO YOUR LETTER OF JAN. 30. 1992 1 MUST APPEAL AND REJECT SAME ENTIRELY. IF I WERE TO BE PARTY TO PRESERVING AND PROTECTING THE WATER SEEPS WHICH ARE UNDERMINING SLADE WAY. THE UTILITIES UNDER SAME AND CREATING DOWN SLOPE LANDSLIDES, I WOULD BE IN DIRECT VIOLATION OF THE WASHINGTON STATE LIC . LAW ; - -I/ TO SAFEGUARD .LIFE. HEALTH, AND PROPERTY " -- RCW 18.08.235. AS WELL AS THE AMERICAN INSTITUTE OF ARCHITECTS CODE OF ETHICS AND PROFESSIONAL CONDUCT - -11 ADVICE . WHICH VIOLATES ANY LAW OR REGULATION AND WHICH WILL . IN THE ARCHITECTS JUDGEMENT, MATERIALLY AFFECT ADVERSELY THE SAFETY TO THE PUBLIC OF THE FINISHED PROJECT, THE ARCHITECT SHALL s REFUSE TO CONSENT TO THE DECISION, AND REPORT THE DECISION TO LOCAL BLDG. INSPECTOR OR OTHER PUBLIC OFFICIALS IN CHARGE - - -" VERY TRULY YOURS LEROY LO .1 A. +(ARCHITECT CC MAYOR. CITY COUNCIL TUKWILA BLDG STAFF C • LEROY C. LOWE A.I.A. ARCHITECT ►.O. sox 1 X141 •f ATT1.f, WA•HINOTON !•111 (4110 [MITE FEB t a 1992 CITY OF TUKWILA ()LANNING DEPT. L . RICK BEELER DIRECTOR, DEPT. OF COMMUNITY DEVELOPMENT 6300 SOUTHCENTER BLVD. SUITE 100 TUKWILA , WA. 98166 DEAR MR . BEELER FEB. 10, 1992 WE HAVE BEEN INVOLVED IN INVESTIGATION AND STUDIES FOR A RESIDENTIAL DEVELOPMENT OF PROPERTY ADJACENT TO AND WEST OF SLADE WAY. OUR WORK HAS, IN PART, RESULTED IN BECOMING AWARE OF CONCERNS OVER SLADE WAY. APPARENTLY THE CITY'S DESIGN AND CONSTRUCTION OF SLADE WAY HAS NOT RESULTED IN A STABLE SITUATION. AS THE CITY IS AWARE, THERE HAS BEEN SINKING OF THE ROADWAY AND ASSOCIATED DOWN HILL. SLIDES. AND AS THE CITY IS AWARE THIS SITUATION HAS LIKELY RESULTED FROM INADEQUATE CONTROL OF SUBTERRANEAN WATER FLOW. APPARENTLY YOUR STAFF AND /OR CONSULTANTS RECOGNIZE THAT THE INSTALLATION OF A FRENCH DRAIN SYSTEM IS AT LEAST ONE THING THAT CAN BE DONE TO STOP THIS PROBLEM. f FEB181992 CITY OF TUKWILA PLANNING DEPT. OUR CONSULTANTS WOULD SUPPORT YOUR EFFORT IN THIS REGARD. SINCE A FRENCH DRAIN INSTALLATION MAY REQUIRE ENTRY AND WORK ON OUR PROPERTY, WE WOULD BE GLAD TO WORK OUT THE APPROPRIATE PERMISSION. VERY TRULY YOURS LEROY C. LOWE A.I.A. ARC CC : JOHN McFARLAND, CITY ADMINISTRATOR GARY SCHULZ , URBAN ENVIRONMENTALIST JACK PACE, SENIOR PLANNER PHIL FRASER, CITY ENGINEER DARREN WILSON, ASSISTANT PLANNER 111 LLCQE T J 7L. aKIO DENNIS JOULE, P,E. CIVIL EVGLNEER r 32729 S.E. alath Street Pau 07, WA 99024 (206) 392 -1106 Leroy C. Lowe, A.I.A. P.O. Box 3972 Bellevue, Washington 98009 January 15, 1992 Project 1442 Re: Hillcrest Dewatcring / Stability of Slade Way Ground & Surface Water Hydraulic Georechnieal Eoidnaerin; F.) \—a( S l5v LF11: 8 1992 CITY PLANNING DEPT At your request I have reviewed the geotechnical reports regarding Hillcrest Subdivision in Tukwila, Washington. The reports reviewed included; Preliminary Geotechnical Investigation for Hillcrest Slade Way, dated May 30, 1990, prepared by Cascade Geotechnical, and a follow -up report titled Hillcrest Way, dated August 27, 1990, also prepared by Cascade GeotechnicaL I have also performed a surface inspection of the site. You have informed me that Slade way, adjacent to the proposed Hillside development, has slope stability problems and has undergone land movement. This report discusses the relationship between dewatering the Hillcrest site and the slope stability of Slade Way. Soil logs from the geotechnical reports show the site to be underlain by slightly silty sands with some interbedded lenses of silt. The Hillcrest site involves a lower, relatively flat bench, with a steep slope to the west. Four springs (or seeps) were observed at the toe of the steep slope. Soil logs show a perched groundwater table within the benched area. Slade Way is downslope and just east of the site. The road bed was constructed cross - slope by cutting upslope and filling downslope. Slope stability is simply the ratio of the magnitude of forces acting to hold the soil in place (shear strength) divided by magnitude of forces acting to drive the soil downslope (soil weight). When water is added to soil, the shear strength goes down and the weight goes up.. From this, it can be seen that adding water to a slope lowers slope stability, dewatenng a slope improves slope stability. Since the Hillcrest site is adjacent to, and upslope, from Slade Way, dewatering the lower portion of the Hillside site will improve the stability of both the Hillside site, and Slade Way. The degree to which the slope stability is improved depends on the degree to which the slope is de- watered. This depends on the location, configuration, and depth of the dewatering facilities. The lower portion of the Hillcrest site has been designated a wetland. If you de -water a wetland, it is no longer a wetland. Thus, you have a problem. De -water the site, remove the wetland, and improve the slope stability; or not. ,Page January 15, 1992 - Project 1442 If Slade Way fails (is involved in a slope failure) the utilities within the road will likely fail also. These utilities involve gas, water, power, sanitary sewer, and storm sewer. The environmental damage downslope from Slade Way that would be caused by the failure of the utility pipes within Slade Way would certainly overshadow the loss of any small wetland that may be present within the Hillcrest site. If Slade Way is currently moving downslope, then Slade Way is involved in a slope failure. As stated above, this report simply discusses the relationship between dewatering the Hillcrest site and the slope stability of Slade Way. It must be the decision of the governing agency as to whether the site should be de- watered, improving the slope stability, or not. Very trul �C. S Jo 1 1 = rc't� I�Q Of w ASyi .( A E, b�, t� • De oule, P.E. 0 �~ :a e /ON AL Eh /111 F ES 18 1992 CITY OF TUK`JVILA PLANNING DEPT. 32729 S.E. 44th Street Fall City, WA 98024 (206) 392-1108 Pedberg Associates, Inc. Post Office Box 1337 Gig Harbor, WA 98335 (206) 858 -7055 January 8, 1992 KROH LFEBI819Sa CITY _OF TUKWILA PLANNING DEPT. Leroy C. Lowe, A.I.A. Architect P.O. Box 3972 Bellevue, WA 98009 RE: Hillcrest Boundary Line Adjustment Tukwila, WA Dear Leroy: This letter is in reference to the wetlands on the above referenced site. A level 1 site walk was performed in August of 1991. The accompanying map shows the approximate edge of wetlands as defined in the three parameter unified methodology. This delineation is based on the topography and spring locations. Additional facts to be considered are: 1) The wetland is not on the City of Tukwila wetland inventory. 2) The wetland is estimated at 7,500 square feet, it is isolated with no connection to any other wetland or stream, it is surrounded by urban area, developed land, and roads. 3) The wetland source is from a series of springs at the base of a the slope. 4) The runoff from the springs and area is collected in the storm water system of Slade Way and tightlined to the, presently under construction, Klickitat stormwater system. 5) A sewer line serving McMicken Heights runs under Slade Way. 6) Slade Way is the eastern border of the property. 7) The geotechnical report and information from several engineers (ENTRANCO, RESCO, Professional Surveyors Inc., Cascade Geotechnical) indicates that Slade Way and the sewer are slipping at the rate of inches per year. 8) The water originating on the subject property saturates the soils under Slade Way and contributes substantially to the slippage problem. 9) If Slade Way has a major slip, then the sanitary sewer is likely to break, creating a major environmental health hazard, and denying sewer service to a large population. page 2 10) If the road slips greatly this could be an immediate hazard to traffic and passersby. 11) Recommended remedial action is to intercept the ground water, dewatering the hillside, and pipe the water into the stormwater system. 12) The dewatering process will drain the wetland. Several scenarios of recreating the wetland have been considered, but there is no practical way of maintaining a wetland and dewatering the hill. The two activities are contradictory. 13) .Deep excavations, 10 + feet in depth, have been considered for placing water tight barriers to redirect the water and save the wetland. This is hazardous as the stratified soils would allow the water to go to a greater depth and continually destabilize the hill; the stability problem of the road would not be solved. 14) Any attempt to preserve the wetland will jeopardize Slade Way and the sewer. 15) The City of Tukwila has provisions in its ordinance for dealing with emergencies and public safety. 16) Exempting this area from the wetland ordinance on the basis of the public safety issue is valid and recommend. 17) A wetland study is unnecessary as the dewatering of the hill is the only reasonable alternative and will result in lowering the water table of the area such that a wetland can not be supported. In summary, a wetland is present and the primary cause of slippage and lack of stability of Slade Way. Slade .Way is slipping and it is a matter of time before the road and sewer cause a major environmental mishap. The remedial action for preventing further slippage involves dewatering the hill by lowering the water table. Lowering the water table will drain the wetland. There is no practical solution to the loss of the wetland. It is recommended, in the interest of public safety and to save time, that the wetland be exempted from further study and remedial action undertaken. It is safe to say that Slade Way will go, someday. Further study and delay enhances the probability that an expensive cleanup will ensue. I hope that common sense prevails to prevent an environmental disaster. If I can be of further assistance, Please contact me. FEB 181992 CITY OF TUKWILA PLANNING DEPT. Mechanical & Civil Engineering 17815 S.E. 146th Renton, WA 98059 (206) 228 -4244 FAX (206) 228-4292 Leroy C. Lowe, A.I.A. P.O. Box 3972 Bellevue, Wa. 98009 February 17, 1992 RE: Hilicrest Boundary Line Adjustment Dewatering and stability Dear Leroy: -- 161..2 CITY OF TU PLANNING o WILA EPT. At your request I once again reviewed your pr referenced project. My review included a site visi of the information supplied by other consultants. There can be no doubt in anyone's mind that S threatened by a potential landslide downslope of your the present conditions are not corrected. Your prope portion of Slade Way East of it are saturated by saturated soil is very heavy and viscous and hence, lead to a very unstable situation. Slade Way is prese as an earthen dam holding the heavy saturated soil in Way was clearly not built or designed to withstand t lateral loads due to the upland saturated soils. The most elementary Geotechnical calculations would demonstrate that Slade Way is not stable within reasonable safety limits. posed above and review ade Way is property if ty and that seeps. The at present, tly serving lace. Slade e potential The other consideration is the presence of a wetland on your property. While I am not a sensitive areas or wetlan is clear from Mr. Bredberg's report and my observation are some wetlands on the property. It appears to me clearly a question of balancing the stability of S the utilities in it along with the corresponding publ safety against the value of the wetland. s expert, it , that there hat there is ade Way and c health and It would seem obvious to me that the logic:1 and most expedient solution to the Slade Way stability problem would be the "controlled responsible" development of your property This would include street frontage, and stormdrain improvements to Slade Way along with on -site drainage, dewatering and stability easures that would assure stability over the entire affected area While I realize that I have not said anything ere that you do not already know, I hope that my comments will be of some help to you. Please call me if you have any questions or nerd additional information. Sincerely, if 4"f' Richard E. Stu h, P.E. Washington State registered mechanical and civil engineerin^ corporation CITY OF TUKWILA 6200 SOUTHCENTER BOULEVARD, TUKWILA, WASHINGTON 98188 MEMORANDUM TO: DARREN WILSON . FROM: PHIL FRASE DATE: SEPTEMBER 16, 1991 SUBJECT: PHONE n f. 061 433 [E U Gary L %anUrxn, .11ayor FEB 18 1992 CITY OF TUKWILA p(,ANNING DEPT. ENVIRONMENTAL COMMENTS FOR HILLCREST (LEROY LOWE) BOUNDARY LINE ADJUSTMENT (CHECKLIST DATED SEPT. 16, 1991) 1. #9 - Name the two soils reports by author and date produced (Include reports in documentation) - Add: "City to conduct peer review of geotech /hydrological studies via independent consultant in order to determine final impacts /mitigations." 2. :;Earth, d -:Add: "Slippage of Slade,.Way; has also occurred it least twiceX 3. Under Item No. 2 Water - Comments are written in such a manner as to not address proposed use of lots, but rather treat the proposal as the act of changing lot lines only. Question: Is'this environmental document for proposed 5 lot configuration for single family use or not? Impacts and mitigations for intended use need to be fully defined in responses based on intended construction for 5 single family dwellings, not just status quo undeveloped use. I request this portion of environmental checklist be redone to include impacts /mitigations with any proposed 5 unit single family development, not just under assumption that only lot line boundaries are being relocated. Second, I request that the assumptions made by the preparer of the environmental checklist identify which soils report they are relying upon in the preparation of the checklist responses so it is clear by what authority the impacts /mitigations have been determined. 4. No. 7 - Utilities - Water Utility requires "loop system" be developed. Noted is that WD #75 states in availability letter, "Water system must be looped to...." indicating that impacts of this development require mitigations for a water main extension looping the system. Public Works requests this loop be in public R /W. How it is located needs to be shown in order to determine if easements are required on plan to mitigate utilities across private lots. 5. No. 7 - Utilities - Storm drainage availability is also identified under Checklist Response No. 7. This is not the case. A storm main extension will be needed to S. 160th Street for the proposed use of property and so needs to be identified to mitigate impacts of said lot line configuration at time of first single family lot construction. Also, detention will be required in the new public line constructed in Slade Way prior to discharge into new 53rd Ave. S. storm line (now under construction). 6. No. 15 Transportation - a. This answer to be changed from n/a to Slade Way /53rd Ave. S. for four single family lots and S. 160th Street for the fifth lot. ,e-tD f'E'°A 2 : ,t>•7/t,2Ch/ W /Gs as) No• 2G • /99/ G. 1.owE . MEMORANDUM Darren Wilson Sept. 16, 1991 page two No. 15 Transportation - a. - Applicant to identify nearest METRO bus stop ..s. WOE FEB 18 1992 CITY OF T UKW ll A pi•ANNING DEPT. No. 15 Transportation - e. through g. - Applicant to provide responses (n /a incorrect). '7. No. 16. Public Services - a. Identify water main loop required and extension of public storm drainage system. Also, identify extension of ped path and sidewalk systems linking Slade way to S. 160th Street. 8. On plan submittal identify how utilities services including storm side drains, water services and sanitary side sewers will be located relative to need to provide any utility easements serving one property across other properties. Do same for franchised utilities (power, telephone, TV cable, WNG). 9.• On plan identify maximum slopes of private drives to allow Public Works to verify accesses demonstrate 15% max. requirement can mitigated under proposed lot configurations. Also, on plan identify proposed realignment of South 160th and how proposed access could configured /mitigated to open access (contact Brian Shelton, 433 -0179 for copy of South 160th Street plans). PRF /cd xc: Brian Shelton file: Hillcrest Development CD.D18.LEROY.PRF 0 rn z LEROY C. LOWE A.I.A. ARCHITECT P.O. BOX 12 Al OCATTI.C. WASHINGTON 00111 DARREN WILSON ASSISTANT PLANNER 6200 SOUTHCENTER BLVD, TUKWILA, WA. 98166 DEAR MR. WILSON rtfitijxrimm FEB 21 1992 CITY OE'T JKWILA PLANNING DEPT. • IIJLbCQEcT FEB. 18, 1992 WE HAVE ATTEMPTED TO DISCUSS THE "REAL AND PRESENT DANGER" OF THE SLADE WAY SLIPPAGE PROBLEM WITH YOU • ON SEVERAL OCCATIONS, YOUR LETTER OF JAN. 30, 1992 WAS RECIEVED BY ME THE EVENING OF FEB, 0, 1992, NEARLY A HALF YEAR AFTER WE. HAD FILED OUR BOUNDARY LINE ADJUSTMENT APPLICATION. ( SEPT. 9, 1992 ) I APPEAL YOUR LETTER DIRECTING ME TO PRESERVE AND PROTECT THE SEEPS ON MY PROPERTY FOR THAT ACTION WOULD PERPETUATE A DANGEROUS SITUATION PLACING SLADE WAY IN PERIL. THE EXPENDITURE FOR WET LAND DELINIATION IS UNREASON- ABLE IN LIGHT OF THE CITYS DEFICIENCY IN HANDLEING THE SLADE WAY CONCERNS. PAGE 2 WE APPEAL TO YOU THE STAFF AND TO THE CITY TO WORK WITH US TO PROVIDE FOR REASONABLE DEVELOPMENT OF OUR PROPERTY AND THE CITYS PROTECTION OF SLADE WAY , THE SANITARY SEWER, AND THE UTILITIES THEREIN. AS DISCUSSED IN THE ATTACHED LETTERS FROM : RESCO, DREDBERG, AND JOULE, YOUR IMMEDIATE ATTENTION TO SLADE WAY AND CONTRIBUTING OFF SITE CONDITIONS IS CRITICAL TO AVOID A REAL AND PRESENT DANGER TO THE HEALTH , WELFARE , AND SAFETY OF THE CITIZENS OF TUKWILA AND KING CO. ATTACHED IS AN INTERNAL MEMO FROM PHIL FRASER TO DARREN WILSON CITING THE SLADE WAY SLIPPAGE PROBLEM. 1 ALSO HAVE HAD DISCUSSIONS WITH RALPH HEITT AN INSPECTOR FOR ENTRANCO WHO HAS A CONTRACT WITH THE CITY OF TUKWILA TO SUPERVISE THE CONSTRUCTION OF KLICKITAT DRIVE Lk S. 160T11 ST. MR. HEITT HAS INDICATED THAT SLADE WAY HAS REAL STABILITY PROBLEMS AND HAS SETTLED SOME TEN INCHES IN THE RECENT PAST. PLEASE LET ME KNOW WI -IAT IT IS YOU WANT TO DO ON MY PROPERTY TO R SOLVE- TI-11 PROBLEM. SINCERELY YOURS LEROY C. LOWE A.I.A. AR HITECT CC : MAYER, CITY COUNCIL TUKWILA BLDG. STAFF . ,' 1 \EB2l199Z CITY UI: TUKWILA ......PL.ANN%NG DEPT. Hydrant No. 1 2 3 WATER FLOW TEST SUMMARY SHEET Outlet [.D. Pitot Press. Flow Residual inches psi gpm psi zYt qo ISSb °12 1125 Scale A Scale B Scale C 120 115 110 105 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 Date: % — 23- 9 I Time: (0; 00 p41Cont. No. Cont. Name: LESLeblY L . d• L • • Address: '4S c- 't Cod1 % ' V 104tLil Static Press: ISO if 1111 1111 iiii 1171 ti1T 1 1 1 1 111111111 psij Flow ® 20 psi 21 (o3 gpm 111171111 II bib,' MIAMI 1111W11 V 111111111 111111111 1111111'11 91 P.S 100 200 300 200 400 600 400 800 1200 400 800 1600 500 1000 2000 600 1200 2400 700 1400 2800 Water Flow gpm 1500 800 1600 3200 900 1800 3600 The Viking Hastings, Litho in U.S.A. 1000 2000 Cowpwation 4000 Michigan fwm No. 3016 Leroy C. Lowe Universal /Land Construction Company P.O. Box 329 Woodinville, Wa. 98072 UNIVELC159RL 483 -6200 Hillcrest July 23, 1992 Preliminary Estimate Page - 1 SITEWORK Bid Quantity Proposal Unit Amounts Unit Price Total Amount 1. Sawcut ex. AC 325.00 L.F. 2.25 731.25 2. Vertical curb & gutter 325.00 L.F. 9.50 3,087.50 3. Concrete sidewalk 185.00 S.Y. 17.60 3,256.00 4. Concrete driveways 4.00 EACH 200.00 800.00 5. 2" Class B asphalt /4" rock for widening 180.00 S.Y. 14.25 2,565.00 6. 1" Overlay on Slade Way 1,200.00 S.Y. 5.10 6,120.00 7. Adjust ex. utilities through overlay 1.00 L.S. 550.00 550.00 8. Traffic control 1.00 L.S. 850.00 850.00 9. Import pit run for subgrade (as required) 0.00 TON 10.25 0.00 10. Clear easements & dispose of debris 760.00 L.F. 10.50 7,980.00 11. Clear driveway /building pad areas 1.00 L.S. 17,600.00 17,600.00 12. Rough grade driveways 1.00 L.S. 28,800.00 28,800.00 13. Load & haul excess /unsuitable material offsite (T &M) 14. Import quarry rock for subgrade (as required) 0.00 TON 17.20 0.00 - *- Marked Items Not Taxable Sub Total Tax 0.082 Total 72,339.75 5,931.86 78,271.61 STORM SYSTEM Bid Quantity Proposal Unit Amounts Unit Price Total Amount 1. 24" Storm 450.00 L.F. 29.50 13,275.00 2. 6" French drain 760.00 L.F. 26.70 20,292.00 3. 48" Type II CB 3.00 EACH 1,750.00 5,250.00 4. Tie to ex. CB 1.00 EACH 490.00 490.00 5. Traffic control 1.00 L.S. 675.00 675.00 6. Import select backfill (as required) 0.00 TON 10.25 0.00 7. Detention (Budget by owner) 1.00 L.S. 12,000.00 12,000.00 - *- Marked Items Not Taxable Sub Total Tax 0.082 Total 51,982.00 4,262.52 56,244.52 Leroy C. Lowe Universal /Land Construction Company P.O. Box 329 Woodinville, Wa. 98072 UNIVELC159RL 483 -6200 Hillcrest July 23, 1992 Preliminary Estimate Page - 2 SANITARY SEWER Bid Quantity Proposal Unit Amounts Unit Price Total Amount 1. Connect to exist. MH 2.00 EACH 990.00 1,980.00 2. Connect to exist. 8" (S. 160th St.) 1.00 EACH 650.00 650.00 3. Connect to ex. stub on Slade 0.00 TON 10.25 0.00 Way 1.00 EACH 500.00 500.00 4. Patch curb & S/W - 160th 1.00 L.S. 950.00 950.00 5. AC trench patching 1.00 L.S. 2,140.00 2,140.00 6. 4" Side sewer - 10' into property 5.00 EACH 670.00 3,350.00 7. Import select backfill (as required) 0.00 TON 10.25 0.00 - *- Marked Items Not Taxable Sub Total Tax 0.082 Total 9,570.00 784.74 10,354.74 WATER Bid Quantity Proposal Unit Amounts Unit Price Total Amount 1. 1" Water service off ex. line 7.00 EACH 620.00 4,340.00 2. AC patching 1.00 L.S. 900.00 900.00 3. Import select backfill (as required) 0.00 TON 10.25 0.00 4. 6x6 Wet tap, incl. valve 1.00 EACH 2,500.00 2,500.00 5. 6" D.I. water 55.00 L.F. 16.00 880.00 6. Hydrant assembly 3.00 EACH 1,620.00 4,860.00 7. 8" DI (Slade Way) 1.00 L.S. 38,550.00 38,550.00 - *- Marked Items Not Taxable Sub Total Tax 0'.082 Total 52,030.00 4,266.46 56,296.46 EROSION CONTROL Bid Quantity Proposal Unit Amounts Unit Price Total Amount 1. Rock entry pad 5.00 EACH 900.00 4,500.00 Continued .on Next Page... Leroy C. Lowe Universal /Land Construction Company P.O. Box 329 Woodinville, Wa. 98072 UNIVELC159RL 483 -6200 Hillcrest July 23, 1992 Preliminary Estimate Page - 3 EROSION CONTROL Bid Quantity Proposal Unit Amounts Unit Price Total Amount 2. Silt fence (If required) 0.00 L.F. 3.25 0.00 3. Straw bales - hand spread (If required) 0.00 EACH 14.50 0.00 4. Hydroseeding (1 AC Min.) (If required) 0.00 ACRE 725.00 0.00 5. Misc. rip rap for check dams (If required) 0.00 TON 20.00 0.00 6. Misc. washed rock for gravel filters (If required) 0.00 TON 20.00 0.00 - *- Marked Items Not Taxable Sub Total Tax 0.082 Total 4,500.00 369.00 4,869.00 NOTES: Bid Quantity Proposal Unit Amounts Unit Price Total Amount 1. Staking & soils testing is not included. Total 0.00 * **it * * * * * * * * * * * A. SUB TOTALSc TAXES AND TOTALS BY PAGE OR SECTION * * * * * * * * * * * * ** PAGE or Activity Description Total Bid Proposal Amounts - - -- Sub Total Tax Total SITEWORK STORM SYSTEM SANITARY SEWER WATER EROSION CONTROL NOTES: 72,339.75 51,982.00 9,570.00 52,030.00 4,500.00 0.00 5,931.86 4,262.52 784.74 4,266.46 369.00 0.00 78,271.61 56,244.52 10,354.74 56,296.46 4,869.00 0.00 Grand Totals 190,421.75 15,614.58 206,036.33 Slides close highway Engineer Dan Kuebler and project inspector Bob Romine, right, confer while standing on the largest of several mudslides that closed the North Cascades Highway Monday afternoon. The one shown is northwest of Rainy Pass. The problems were triggered when a heavy rain soaked previously dry ground in steep terrain. The state Department of Transportation opened one lane to traffic yesterday evening and hoped to have the road fully open today, depending on the extent of damage. The popular scenic state Highway 20 was closed from Marblemount to Winthrop by the slides and flash floods from the rainstorm, which was described by Romine as "the heaviest rain I've ever seen." Motorists could still reach Ross Lake Recreational Area by driving over Diablo Dam, department spokesman Harold Garrett said. Snoqualmie Pass on Interstate 90 or U.S. 2 over Stevens Pass are alternate routes across the Cascades. No injuries were reported, but the closure caused inconvenience during the height of the vacation season. GRANT M. HALLER/P -I North Cascades Highway closure WASH. 9oss Like - - -- . -r - deIIInpha m ...:,....'.3' ec. Area • Pass MUM • re:r STEVE GREENBERG/P -I .... .,................ City of Tukwila Department of Community Development STAFF REPORT to the PLANNING COMMISSION Prepared July 23, 1992 HEARING DATE: PROJECT: APPLICANT: PROPOSAL: LOCATION: ZONING: COMPREHENSIVE PLAN DESIGNATION: SEPA DETERMINATION: STAFF: ATTACHMENTS: July 30, 1992 L92 -0057, Hillcrest BLA, APRD Special Permission 92 -3 LeRoy Lowe Reasonable Use Exception Slade Way S.and S. 160th St., Tukwila, WA. R1 -12.0 Single Family Residential John W. Rants, Mayor Rick Beeler, Director Single - Family Residential Not Required Jack Pace, Senior Planner Gary Schulz, Urban Environmentalist A. Applicant's submittal dated June 15, 1992 B. _ . Sensitive Area Ordinance 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 431-3665 Staff Report to the Planning Commission FINDINGS BACKGROUND L92 -0057: Hillcrest Page 2 The City Council adopted the Sensitive Areas Ordinance on June 10, 1991. The applicant submitted his Boundary Line Adjustment on September 6, 1991. On February 18, 1992, Mr. Lowe appealed the Director of Community Development's decision to require a wetland study. The Planning Commission held a public hearing on March 26, 1992 and upheld the Director's decision. The wetland study was submitted to the City on April 20, 1992. The Urban Environmentalist assisted the applicant's wetland consultant with needed revisions for the wetland boundary. As a result, a revised wetland report was submitted on May 15, 1992. The wetland study was verified and approved by City staff. However, the study does not address the applicant's position of eliminating wetlands on the site. The applicant was informed of the mitigation requirements at both the June 3, 1992 and June 24, 1992 meetings. On June 15, 1992, the applicant submitted his request for Reasonable Use Exception under Section 18.45.115 of the Zoning Code (SAO). On July 17, staff advised Mr. Lowe that is was not clear that the application of the SAO would deny all reasonable use of the property and staff was concerned that moving ahead now with the Reasonable Use Exception would further delay the applicant's efforts to develop his property. DECISION CRITERIA Zoning Code Section 18.45.115 C Reasonable Use Exceptions 1. If application of this Chapter would deny all reasonable use of the property containing wetlands, watercourses or their buffers, the property owner or the proponent of a development proposal may apply for a reasonable use exception. 2. The application for a reasonable use exception shall be in a format specified by a filed with the Department of Community Development. Requirements may include an environmental impact statement pursuant to Washington Administrative Code 197 -11 -400. Reasonable use exceptions shall be decided by the Planning Commission following a public hearing notice as specified in 18.92. Staff Report to the L92 -0057: Hillcrest Planning Commission Page 3 3. If the applicant demonstrates to the satisfaction of the Planning Commission that application of this Chapter would deny all reasonable use of the property, development may be allowed which is consistent with the general purposes of this ordinance and the public interest. In Mr. Lowe's letter dated June 15, 1992, he stated; "We are being denied reasonable use of this property by application of the Sensitive Area Ordinance. We therefore request a Reasonable Use Exception be granted under Art. 18.45.115 S.A.O. Item (A) West portion of property unbuildable for required road to same will not meet Fire Marshall's standards; i.e. 15% max. roadway slope is not possible. Item (B) Lot #6 unmarketable because of size, shape and topography. (See attached realty letter.) Item (C) To preserve and protect the wetlands would unreasonably threaten the public health, safety, and welfare. This wetland pumps water into the down slope aquifer destabilizing Slade Way and the down slope property. (See reports furnished to Planning Commission Mar. 26, 1992)." Attachment A contains the material supporting the request for Reasonable Use Exception. Under Reasonable Use Exception; the application of the Sensitive Area Ordinance would deny all reasonable use of the property, the applicant may apply for a reasonable use exception. The applicant has six pre - existing legal lots of record. The Zoning Code States; Section 18.70.030: "An authorized use or structure may be erected on a pre - existing legal lot and containing less area than required by the zone district in which is located; provided, the front, side and year yard requirements as well as other applicable dimensional standards of this title are met." Given the existing shape of these lots, the applicant may have three or four buildable sites due to the setback requirements. The applicant is proposing a Boundary Line Adjustment for five lots to meet setback requirements. The Boundary Line Adjustment is an Administrative process. Staff has advised the applicant the following development issues need to be addressed to complete the Boundary Line adjustment: Staff Report to the L92 -0057: Hillcrest Planning Commission Page 4 WETLANDS: * The wetland delineation work, completed by your wetland consultant with assistance by the City's Urban Environmentalist, has determined total sizes and configurations of the wetland areas. Specific wetland boundary revisions included additional flagging for Wetland A and the delineation of Wetland D. * The current wetland boundaries are verified; however, the additional flagging of Wetland A will need to be surveyed prior to the completion of this project. * Because all on -site wetlands are less than 1.0 acres in area and have less than three wetland classes, they are rated as Type 3. The standard buffer width for Type 3 wetlands is 25 feet. A 15 -foot minimum buffer may be allowed with an approved buffer enhancement plan. Due to its small size, Wetland D is exempt from regulation. * Until a peer review /geotechnical study is completed, the City's position on wetland use is to preserve the northern half of the wetland area. This portion of the site has the most significant groundwater discharge and detention. * With the exception of Wetland D, wetland mitigation is required for all regulated wetlands. Any proposed alteration to the on -site Type 3 wetlands must include a wetland mitigation plan. To review a wetland alteration proposal, mitigation measures should be proposed as a conceptual plan for identifying potential impacts and providing adequate replacement of wetland area and function. SETBACKS: * Identifying setbacks on the site plan. All setbacks under the APRD may be reduced with DCD Director's approval. (Section 18.46.060(a)3).) PUBLIC FACILITIES: * Downstream drainage facilities (including WSDOT) of this development lack capacity for any added surface or subsurface discharges. Therefore, this development is restricted to on -site detention facilities that reduce discharge rates. * The existing water system provides limited capacity to serve your development. A looped system is necessary to provide reliable fire /domestic flows for the intended use. You need to work with Highline Water District (Jay Gibson) to obtain any joint funding for the required public water main 53 Ave. S. This Staff Report to the Planning Commission L92 -0057: Hillcrest Page 5 will tie the existing systems at Slade Way and S. 160 Street together. A the meeting the Highline Water representative was agreeable to presenting the joint funding (cost sharing) concept to his commissioners. * Water and sewer availability letters need to be included in your submittal and be based on the final lot configuration. * If any utilities, access areas, or preserved wetlands /springs require easements across lot lines in the new reconfigured lot line proposal, these easements must be show as part of the submittal. In conjunction with these development issues, the city would do peer review of the geotechnical/hydrological reports. The peer review scope of work would include risk assessment for the potential to develop portions of the property while maintaining on -site and off -site stability. Public Works estimates the Hillcrest peer review should be completed in eight to ten weeks. Under Section 18.45.115 (C)(4), the Planning Commission, in granting approval of the reasonable use exception, must determine that the following criteria have been met. Criteria A: No reasonable use with less impact on the sensitive area and its buffer is possible; The applicant has not been willing to propose alternatives with less impact on the sensitive area - wetlands. Criteria B: There is no feasible on -site alternative to the proposed activities, including reduction in size or density, phasing of project implementation, change in timing activities, revision of road and lot layout, and /or related site planning activities that would allow a reasonable economic use with fewer adverse impacts to the sensitive area and its buffer; The applicant has several alternatives available which consist of: 1) Reducing the number of lots proposed for development. 2) Providing on or off-site wetland mitigation; 3) Revising the lot design and road access. Criteria C: As a result of the proposed development there will be no increased or unreasonable threat of damage to off-site public or private property and no threat to the public health, safety or welfare on or off the development proposal site; Staff Report to the L92 -0057: Hillcrest Planning Commission Page 6 The applicant's have stated: "To preserve and protect the wetlands would unreasonably threaten the public health, safety, and welfare. This wetland pumps water into the down slope aquifer destabilizing Slade Way and the down slope property." Dennis Joule, P.E. provided the applicant with a letter (1- 15 -92) that included a discussion of dewatering to improve slope stability. This letter did not represent a site - specific study or refute the site - specific findings of the Cascade Geotechnical, Inc. reports of 5- 30 -90, 8- 27 -90, and 4- 24 -91. In addition, there were no clear recommendations indicating the site must be dewatered. The letter written by Richard Stuth, P.E. (2- 17 -92) recommends "controlled responsible development..." and "... dewatering and stability measures that would assure stability over the entire affected area." This statement does not imply that the entire site must be dewatered as a prerequisite for some type of development. As noted earlier, the City will be doing a peer review of the geotechnical/hydrological reports. The applicant was not willing to wait for this review before requesting the Reasonable Use Exception. Criteria D: Alterations permitted shall be the minimum necessary to allow for reasonable use of the property; The applicant has not proposed any mitigation either on -site or off -site to reduce the impact of his proposed development. Criteria E: The proposed development is compatible in design, scale and use with other development with similar site constraints in the immediate vicinity of the subject property; The proposed Boundary Line Adjustment would permit single family house similar to development around the site. Criteria F: Disturbance of sensitive areas has been minimized by locating the necessary alterations in the buffers to the greatest extent possible; As noted earlier, the applicant has not proposed any alternative that would minimize the impacts. Criteria G: The inability to derive reasonable use of the property is not the result of actions by the applicant in segregating or dividing the property and creating the undevelopable condition after the effective date of this Chapter; and Staff Report to the L92 -0057: Hillcrest Planning Commission Page 7 The applicant's proposal is to increase the degree in which the existing lots of record could be developed. Criteria H: Any approved alteration of a sensitive area under this section shall be subject to conditions as established by this chapter and will require mitigation under an approved mitigation plan. If a development is approved as a reasonable use, Board of Architectural process, review and standards shall be applied. Staff believes it is premature to request a Reasonable Use Exception. There are design alternatives and additional information that must be obtained before specific mitigation measures can be recommended. CONCLUSIONS 1) The applicant has not shown how the application of the Sensitive areas Ordinance would deny all reasonable use of the property. The applicant is proposing five lots for building; when he currently only has three or four lots which are buildable. 2) The Commission, in granting approval of the reasonable use exception, must determine that criteria A thru H have been met. Staff concluded only Criteria E has been met at this time. 3) The applicant has not shown or proven that there is no reasonable use with less impact on the wetland and its buffer. 4) The applicant has expressed concern for the potential threat of damage to off -site public or private property and public safety. Staff believes the statement about dewatering does not imply that the entire site must be dewatered as a prerequisite for some type of development. Staff believes the request for responsible use is premature until the peer review has been completed and alternative development proposals have been reviewed. RECOMMENDATION Based upon the information submitted, staff recommends the request for Reasonable Use Exception be denied. ADMINISTI.ATIVE PLANNED RESIDENTIAL DEVELOPMENT APPLICATION ^:ITY OF TUKWILA 6300 Southcenter Boulevard, Tukwila, WA 98188 = :'EPARTMENT OF COMMUNITY DEVELOPMENT Telephone: (206) 431 -3680 5. Name: Address: LgX-O y C. / .d•. AQGI /,7 r P. o, Box 39 7 2 �! yc% VIA. 96009' (I'lione• 454. 44 7.3 (s06) 747- 2:470 Signatur- ' C.;. Date. .SEo7. .3, /79/ * The appli•ant/is the person whom the staff will contact regarding the application, and to whom all notices and ports shall be sent, unless otherwise stipulated by applicant. PROPERTY OWNER AFFIDAVIT OF OWNERSHIP Name: thA y c. �ow� ,4, /,,4 . A/zczi/ 7:== 7 Address: P - 130X 3,7 Z Ph 464- 44 I /WE,[signature(s)) \ swear that we are in this application an application are true a er(s) or contra tk at the foregoing st d correct to the VUc K/,4 (zoc--) 74 7• Z4 70 purchaser(s) of the property involved tements and answers contained in this of my /our knowledge and belief. Date: APT 3, X99/ nlLLcZsr ADMINISTRATIVE PLANNED RESIDENTIAL DEVELOPMENT INFORMATION CITY OF TUKWILA DEPARTMENT OF COMMUNITY DEVELOPMENT 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431 -3680 The Planned Residential Development (PRD) process, by permitting flexibility in zoning code requirements, encourages imaginative site and building design, accommodates environmentally sensitive areas and creates open space in residential developments . The number of dwelling units is determined by the underlying zoning district, and minimum lot sizes, building height limits and setbacks are waived. A density bonus of 20% may be allowed in R -2, R -3, R -4 and RMH, subject to adherence to the bonus criteria. The area encompassing the sensitive area and buffers must be devoted to open space that is owned and maintained under one ownership, by a homeowners association or dedicated to the City (if adjacent to a City trail or park). If you are platting property with sensitive areas or sensitive area buffers, you must submit a PRD. CRITERIA The Short Subdivision Committee's decision shall include the following findings: 1. Requirements of the subdivision code for the proposed development have been met, if appropriate; 2. Reasons for density bonuses meet the bonus criteria; 3. Adverse environmental impacts have been mitigated; 4. Compliance of the proposal to PRD and sensitive area requirements; 5. Time limitations, if any, for the entire development and specified stages have been documented in the application; 6. Development in accordance with the comprehensive land use policy plan and other relevant plans; 7. Compliance with the BAR review guidelines (TMC 18.60.050); and 8. Appropriate retention and preservation of existing trees and vegetation recom- mended by the Director of Community Development. PROCEDURE A Short Subdivision Committee meeting will be scheduled when art environmental determination has been made on your application. Notification of the meeting will be sent to all property owners within 300 feet of the subject site. • CITY OF TUKWILA DEPARTMENT OF COMMUNITY DEVELOPMENT Single Family Residential Environmental Checklist When a Checklist is Required: Property owners who wish to develop or remodel a home on a parcel mapped as a sensitive area must complete and submit an environmental checklist. Sensitive areas are lands which slope 15% or more, have a watercourse or wetland on them or are in a coal mine or seismic hazard area. Maps have been made of all of these areas by the City, with the best available information, and are available for your review. Purpose of Checklist: The State Environmental Policy Act (SEPA), chapter 43.21C RCW, requires Tukwila to consider the environmental impacts of your proposal before making decisions. The purpose of this checklist is to provide information to help you and Tukwila identify impacts from your proposal and to reduce or avoid those impacts. Instruction for Applicants: A determination of nonsignificance must be made by the Director of Community Development before you may apply for a building or land altering permit. A fee of $225.00, a completed environmental checklist and a site plan, and any additional information that will help describe your proposal or its environmental effects, must be submitted to the Department of Community Development in order for the determination to be made. This environmental checklist asks you to describe some basic information about your proposal. Answer each question briefly, accurately, with the most precise information known, or give the best description you can to the best of your knowledge. In most cases, you should be able to answer the questions from your own observations or project plans, without the need to hire experts. If you really do not know the answer, or if a question does not apply to your proposal, write "do not know" or "does not apply ". Complete answers to the questions now may avoid unnecessary delays later. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels of land. DE r ERMINATION OF t11LLCIZ6T 1. Description of proposal: Zot.hviciztRy /AZ ,4 Jcis APPUG 47/G,V 2. Name of applicant: LE 'oy ./ w.e .4. /. ,d , ,4,C'c, 1/ ; -::.,y 3. Location of site (use address, lot & block number, and tax account number(s) if ap licable): PY�70NS orc Z°7S. ?9, ?e, C'7, �G, ":5 G S //a' 'S7;- WA>/ T4X Lo7S 0 ZZG cz2 ¢, aZZo, OZiS For completion by staff: Lead Agency: City of Tukwila File No. EPIC The City has determined that the proposal will not have a probable significant adverse impact on the environment. An environmental impact statement (EIS) is not required under RCW 43.210- 030(2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. This information is available to the public on request. ❑ The decision was also made because of specific conditions attached to the proposal. This DNS is issued under WAC 197 -11- 340(2). Comments must be submitted by ,'.The City will not act on this proposal for days from the date below.:::::::;: L. Rick Beeler, Responsible Official Director, Department of Community Development, 431- 3681 6.300 Southcenter Blvd., Suite 100, Tukwila, WA `:9816 Date : Signature . :....: You may appeal this determination to the City Clerk at City Hall, 6200 Southcenter Boulevard, Tukwila, WA 98188, no later than 10 days from the above :date by. written ;. appeal stating the basis of the appeal for specific factual objections. You may be required to bear some of the expenses for an appeal Copies of the procedures for SEPA appeals are available: from the City: Clerk an Department of Community Development: HIL.ccZs7 4. ate checklist prepared: c.re"=7 3, /9'/ 5. • ddress of applicant: red:). BOX Wei • 9800 6. hone number of applicant: <Z°G) 4,6-4.- 412 3 7. . Proposed starting date (including phasing, if applicable): 4 E10. Proposed completion date: /v..4 Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. NC Are there any soils reports or topographic (contour) maps that have been prepared relating to the property? YB. List the government approvals or permits that will be needed for your proposal. C /Ty OF' 77-6‹w/G,a ; 8041A1C4Ry G /NE / 7 04 3?Ov4L . Give brief, complete description of your proposal: Site size: /07, ?8 0 S"4 ' T House size: N, d . Accessory structures: N. 4 , Proposed uses: _/i-L. ° F..o/41/Ly Lois RONMENTAL ELEMENTS Earth a. General description of the site (circle one): Flat, rolling, hilly, steep slopes, other: C OM$N4D 'v 0 ,cz-e, Re'Ll. /NG SLai°` b. What is the steepest slope on the site (approximate percent slope)? 39 % c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, muck)? If you know the classification of agricultural soils, specify them and note any prime farmland. _ 7Z7, cS0 /e- V...■ /N= 7b S d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. Godiciz,s4.40 s ,lf dv� OcGui2erc 7c 6 2.114.5• T, .444"e SS . 1 t1ILGCTZs: e. Describe the purpose, type, and approximate quantities of any filling or grading proposed: 2700 Ca. FT. feWZ p/ EA/ a A /N. Where is the source of fill obtained: Rcc.< 4Y eey % ea/ ZA ✓EL .00% 7" . • f. Could erosion occur as a result f clearing, construction, or use? If so, generally describe. /VA foie ectiA Da.. y Lmvc 4-4)�J. So/15 E2os/GN M.4 )/ GY -GU,e zLI,2 //,/G GR.bO /NG C ,.P'1 T/ /V S' L /M /7 O TD C /G10.5 o,= ,C,ey W4t /.& g. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: /NSTLJLL S /L7224477cw .5.4s/A.es .D.24 /N,4rod vet. /sS/ c 47- es , Re- PL.cA/T, re's-be! 4c4/N cc"vT.�OL 577Zt�7'7.1,e.CS h. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? N/14 L,'I5 .4cLiu577•!=",T �IPvG/ GAP TicN o,vLY. 2. Water a. Surface: 1) Is there any surface water on or in the immediate vicinity of the site (including year -round and seasonal watercourses, ponds, wetlands)? If yes, describe the nature of the water. If appropriate, state what stream or river it flows into. 6/7 jcenT L'S7 QAv 77../KL47Gals W6'''72-4MC' /Nv: A roe'. 2) Will the project require any work over, in, or adjacent to (within 200 feet) the described water? If yes, please describe and attach available plans. N/4 BouNLL4 .. / L ./NZ G477 4N4- 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material: 29ce c.F. pie LaT ,QG1C .• Q 61.47RQ y - G+e.4 VEG. , / T 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities, if known. C A/ /-1 4:3e.04 W /LL. /A./ GL��'T S�O4 G6 A+'VD O //C EG7 ,=LOW /A/ 7-0 BX /57"/,/G 5F f-7 5) Does th- • roposal lie within a 100 -year ,floodplain? es- • ✓ If so, note location on your site plan. 2 iIILLCZ6T 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of dischar e. No N/A Bou/v y L /Nc A0c tisrA1FV7 ,IOs=L /c ci77 ,\/ c Ly b. Ground: 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities, if known. ./=.Z✓vG:.! ,p.2a /N 4 /Z-G /Nr ,E''C 7 GP,o[./"/ W.4 TO A//o A/vo Ve...e T /N 7b Sx257 is '7e,�t -1 2) Describe waste materials that will be discharged into the ground from septic tanks or other sources. Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve._ u vo.4'y L / , 4at.J(JSTM�/./ 4', i' ,/GA 77 0"./ o/V .>/ c. Water Runoff (including storm water): 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, , if known). S. -GAGE P2cn-7 SP2itiG S c�GG��To Y /=z9..././c,41 ,4avo L7/.2 7 S /AI7 Where will this water flow? &x /ST /NG .5-72>=A-) L-A /N Will this water flow into other waters? C JL-y A 5 M•4 Y y S X /.$ TG. '' 1 If so, describe. .C>2.4- /.vtl• .Sy57,�7'I 2) Could waste materials enter ground or surface waters? If so, generally describe. N/4 Y L../A/' .40‘./US i Mc�� /�/ T ,4,4' C.4 770h' OA/Z.,. By 4 G?vEN 6-7-EL CC1L. V 7 04-C) Gy..E'EGT�„G7 /A/7 -O AN �X /4ST //sIG cS7aiE'/"1 --WA sCwF.,<, �ySrEM. CLOSED FLOWER IIILLOZ6T OPEN FLOWER LIGULE BLADE REED CANARY GRASS %VC BASAL SHEATHS STAMEN RISTLE C's SCALE SPIKE-RUSH This large strongly rhiromatous perennial grass hat round hollow stems reaching 0.7.1.4 (2.5•5) In height. The grass is common In wet soils and may be cut These I or perennial grass•like herbs have round to fl•ttened stems and fr hay. tend to grow In clumps In areas with wet soil. IN 5i FLOWER CLUSTER BRACTioji; 11 TRIANGULAR STEMS SHEATHING LEAF BASE ftltik5Z- 44./SkS, ,st.:TIF.■FLOWER CLUSTER • 11 I .: SEDGES YIants Check and then circle types of vegetation found on the site: EJdeciduous tree: other: • - • MATURE LEAF *— YOUNG LEAF RESINOUS BUD PETIOL 1 FRUIT (UNOPENED) HILLCIZE1 BLACK COTTONWOOD A rough•b•H•d Ira. reaching 50 or 60m (160.2001 In h•Ight, Black Cottonwood *. is of *.n found standing above the surrounding woods. They occur on stream banks an lakeshores, and in 'wrested wetlands. Young trees have smooth green b•rli which forms hard dark pray ridges as the tree matures. The winter buds •r• term long pointed and distinctly r•sinous. E evergreen tree: other: CONE NEEDLE NEEDLES OF VARYING LENGTHS 2•WHITE STRIPES WESTERN HEMLOCK A for•st •vergr••n of up to 60-70m (150-200') high, Western Hemlock has distinctively drooping branches and tips, and strongly lurrowed dark to rid- dish-brown bark. Under certain conditions It may be found with Western Find Cedar very old stands with little growing beneath the tr••s. shrubs: willow, sa4merrberry, Indiarrpiten, other: 253LA ,t5Eizi:Zy PURPLE FLOWER ORANGE•RED BERRIES +—THORNY .STEMS SALMONBERRY FUZZY NEW LEAVES-- STIPULES LOST ON OLDER GROWTH WILLOW This deciduous tree or shrub 11 owns round growing with Red Alders along the The tangles of curving, thorny stems formed by this perennial shrub provide ..... /. 1. l4fffieu11 10 id•ntifv willows to shelter for ri•stinp wird; and amen rod•nts. 11 is found growing 1-4m (3.12') 0 pasture 0 crop or grain ' o wet soil plants: eittaill betteretip, 19t2.141trsh:„. skunk cabbage, other MALE FLOWERS .....,•.1 FEMALE FLOWER SI SHEATHING I LEAF-BASES - CATTAIL The el•sslc plants •ssociehed with marshy 5,5.5, loan laf9e. almost puli strondS 1•3111 (34) fall In shallow pule, water. They provide covet and nesting areas lot many birds. and a food source for many •nimals. The roolli. *Wm base, and very young glower stalks are isclIble. Emergent Plants 1-1 water plants: eF-14y, eclgra3s, '' other 7/1-S L.5.:Ar..•—•AFRACT WHITE FLOWERS •••\ • DRACT•c $..., • PURPLE RIDDED STEMS :• • • r WATER PARSLEY Other types of vegetation Please list /vy, ,ey s s DAiveZ/de:,,v StivoRr, Ap. 4 e•'• A1/4-'71= /.,/ hIGLCIZdT b. What kind and amount of vegetation will be removed or altered? 77A/ .4 T ACEA/c.A / ,c).2.4/^/ .A-1 VE0 .4NC7 �Lr4NT�G� c. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: N.477 ✓. W /G:. /h/ L.4"/csc., 4, ' /'-/G 45 W.1-t. As cc, MP47 /E.(— O,EWZA-1 t / 74! VA /E T /ES 4. Animals a. Circle any birds and animals which have been observed on or near the site or are know to be on or near the site: birds: lk, horen, ease, scugbirds, other: ,2o .a /n/S Spd, .5 mammals: ems, bees, el be v r, other: M /G� fish: , front, ether: ,Non/re b. List any threatened or endangered species known to be on or near the site. N/4 A/c)",/L c. Is the site part of a migration route? If so, explain. NIA d. Proposed measures to preserve or enhance wildlife, if any: N/A 5. Land and Shoreline Use a. What is the current use of the site and adjacent properties? .5/74.T- SE• T /S 0 i / 1/A1SN T GGA/O .40-44C-="/ T P.CoPe."2T/ Gov -41-Z- aES ,4 •ems aE ✓ELopEG 5 /�/G L �•4t -7 /L Y S✓IJ�`/Cc� S . b. Describe any structures on the site. A/bA' c. Will any structures be demolished? If so, what? N /V° /VC d. What is the current zoning classification of the site? /- /Z.O ,S /ivGz. , 4/►T /L, y 8 hILLCZcST e. What is the current comprehensive plan designation of the site? ,5/NL / +41M /L y iC45,.5 /,lcE�/CiG► L f. If applicable, what is the current shoreline master program designation of the site? Urban A/A Has any part of the site been classified as an "environmentally sensitive' area? If so, specify. yes , s9P Slr_?cks g• 6. Aesthetics a. What is the tallest height of any proposed structure(s), not including antennas? N/4 BOz.bvo. y .4.0 45TM6*\/ i e)A./ Glis/G)/ b. What views in the immediate vicinity would be altered or obstructed? N/A c. Proposed measures to reduce or control aesthetic impacts, if any: N/A 7. Utilities a. Circle . 'lib - -ntl ' av • . e at the sit-: refuse se!ce sy3tem, other: k1/Z',•• sys �I G464. E 77 V. PLI.BL/C ?".4A/5 774- 7/ctvV b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed._ N /4. eoer1A/..4 y ✓.v .da✓u -7 ' T 4, 'L./C4 770"/ 0A/G. V . Sw ACGO /A/ 4, £/ P� /vs , such E57 Fu 7'v2L✓ UT /Ui /E� Although the following are important elements of the environment, most individual single family construction projects will not have a measurable effect on them. If impacts are anticipated due to your project, please indicate where appropriate. Complete the checklist by continuing with Number 17. 8. Air a. What types of emissions to the air would result from the proposal (i.e., dust, automobile odors, industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known. N/A b. Are there any off -site sources of emissions or odor that may affect your proposal? If so, generally describe. N/A c. Proposed measures to reduce or control emissions or other impacts to air, if. any: NM A 9 9. Energy and Natural Resources HILLCIZE6T a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. N/A b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. N/A c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: N/A 10. Environmental Health a. Arc there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. N/A 1) Describe special emergency services that might be required. N/A 2) Proposed measures to reduce or control environmental health hazards, if any: N/A 11. Housing a. Approximately how many units %%ould be provided, if any? Indicate whether high, middle, or low- income housing? One 5- , /'..J /7.5 MxpOI,, /jycc TL b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low- income housing. N/A c. Proposed measures to reduce or control housing impacts, if any: None 12. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? N/A b. Could light or glare from the finished project be a safety hazard or interfere with views? N/A c. What existing off -site sources of light or glare may affect your proposal? N/A d. Proposed measures to reduce or control light and glare impacts, if any: 13. Recreation a. What designed and informal recreational opportunities are in the immediate vicinity? N/A b. Would the proposed project displace any existing recreational uses? If so, describe. N/A c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: N/A 10 IIILLCIZeST 14. Historic and Cultural Preservation a. Are there any places or objects listed on, or proposed for, national, state, or local preservation registers known to be on or next to the site? if so, generally describe. N/A b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. NIA c. Proposed measures to reduce or control impacts, if any: N/A 15. Transportation a. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. N/A b. Is the site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? N/A ► e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. N/A f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. N/A g. Proposed measures to reduce or control transportation impacts, if any: N/A 16. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally describe. N/A b. Proposed measures to reduce or control direct impacts on public services, if any. N/A 17. Signature The above answers are true and complete to the best of my knowledge. I understa that the head agency is relying on them to make its decision. r Signature: Date Submitted: 'cf6PT /lv /9?/ 11 18.44.150. Speoiiio use rez:ulat ions -high impact Chapter 16.45 enviro: rrr • SENSITII -7 AREAS OVERLAY ZONE All 'uses allowed in the un &_ .ying zoning district shall be allowed in the high impact environment. Sewkns: (Ord 1247 §l(part), 1982) 18.44.160 Variances. Variances shall be processed by the Board of Adjustment in accordance with the shoreline regulations. (Ord 1247 §!(part), 1982) 18.44.170 Appeals. Appeals of any decision regarding granting or denial on shoreline substantial development permits may be appealed pursuant to the appeal procedure as set forth in the shoreline regulations. (Ord 1247 §!(part), 1982) ATTACHMENT B 18.45.010 18.45.020 18.45.030 18.45.040 18.45.060 18.45.080 18.45.090 18.45.115 18.45.120• 18.45.125 18.45.130 18.45.135 18.45.140 Purpose. Sensitive area designation, rating methodologies, classifications and applicability. Interpretation. Sensitive area buffers. Procedures. Uses and standards. Sensitive areas tracts. Exceptions. Variances. Appeals. Recording required. Assurance device. Assessment relief. (8.45:010 Purpose. (a) The purpose of the Sensitive Areas Overlay Zone is to establish special standards for the use and development of lands based on the existence of natural conditions thereon in order to protect environmentally sensitive areas, including the natural character of Tukwila's wooded hillsides. (b) Standards are hereby established to meet the following goals of protecting environmentally sensitive areas: • (1) Minimize developmental impacts on the natural functions and values of these areas. (2) Protect quantity and quality of water resources. (3) Minimize turbidity and pollution of wetlands and fish - bearing waters and maintain wildlife habitat (4) Prevent erosion and the loss of slope and soil stability caused by the removal of trees, shrubs, and root systems of vegetative cover. (5) Protect the public against avoidable losses, public emergency rescue and relief operations cost, and subsidy cost of public mitigation from landslide, subsidence, erosion and flooding. (6). Protect the community's aesthetic resources and distinctive features of natural lands and wooded Hillsides. (7) Prevent unlawful disturbance of archaeologic or geologic sites with historic or prehistoric artifacts. (8) .Balance the private rights of individual property owners with the preservation of envi- ronmentally sensitive areas. (9) Prevent the loss of wetland and watercourse function and acreage, and strive for a gain over present conditions. (Ord 1599 §3(part) 1991) Page 18-35 18.45.020 Sensitive area designation — rating methodologies — classifications and app ability. (a) This chapter applies to any use or develop- ment proposed on any legal lot of record, any portion of which is a sensitive area or a sensitive area buffer as defined in Sections 18.06.695 and 18.06.697, and specif- ically including one or more of the following and their buffers: (1) Abandoned coal mines; (2) Areas of potential geologic instability: Class 2, 3, 4 and seismic instability areas (Section 18.06.050 and subsection (e) of this section); (3) Wetlands (18.06.939); (4) Watercourses (18.06.935); (5) Areas that contain archaeological remnants of value to the archaeological research community, which includes but is not limited to colleges, universities or societies of professional archaeologists, or which is designated as important to save as a record of the area's past by the State Office of Archaeology and Historic Preservation. (b) Sensitive Areas Maps and Inventories. (1) The distribution of many sensitive areas in Tukwila is displayed on the Sensitive Areas Maps, dated 1990, and on file with the Department of Community Development (DCD). (2) Studies, preliminary inventories and ratings of potential sensitive areas are on file with the DCD in the Sensitive Areas Notebook, dated May 1990. (3) The maps and preliminary inventories and ratings are hereby adopted by reference. The actual presence or absence of sensitive areas as defined by or otherwise referred to in this chapter and as determined by the City will govern. The actual ratings and buffers for any sensitive area will be determined by the City using the methodologies and procedures .provided in this chapter for each type of sensitive area. (4) All revisions, updates and reprinting of sensitive areas maps, inventories, ratings and buffers shall conform to this chapter. (c) Wetlands. For the purposes of this chapter, "wetlands" is defined in Section 18.06.939. A wetland boundary is the line delineating the outer edge of a wetland established by using the "Federal Manual for Identifying and Delineating Jurisdictional Wetlands," dated January 10, 1989, as revised or updated, and jointly published by the U.S. Environmental Protection Agency, the U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineers, and the U.S. Soil Conservation Service. Wetland types and rating criteria are listed below: (1) Type 1 wetlands, those wetlands which meet any of the following criteria: (A) The presence of species listed by the federal government or State as endangered or threat- _ ened, or the presence of critical or outstanding actual - habitat for those species, (B) Having forty to sixty percent perrnb nent open water i iispersed patches with two or more classes of vegtidon, - (C) Equal to or greater than five acres in size and having three or more wetland classes, one of which may be substituted by permanent or open water; or (2) Type 2 wetlands, those wetlands which meet any of the following criteria: (A) Greater than one acre in size, (B) Equal to or less than one acre in size and having three or more wetland classes, (C) Equal to or less than one acre, that have a forested wetland class comprised of at least twenty percent coverage of total surface area, or (D) The presence of heron rookeries or raptor nesting trees, (E) The presence of native plant associa- tions of infrequent occurrence; (3) Type 3 wetlands, those wetlands which are equal to or less than one acre in size and that have two or fewer wetland classes. For the purposes of this section, the U.S. Fish and Wildlife Service's "Classification of Wetlands and Deepwater Habitats of the United States FWS /OBS- 79/31" (Cowardin et al., 1979), contains the descrip- tions of wetland classes and subclasses. (d) Watercourses. For the purposes of this chap- ter, "watercourses" is defined in Section 18.06.935. The City "Watercourse Study" (1990) includes the methodology and criteria that will be used for deter- mining watercourse ratings. Watercourse ratings are based on the existing habitat functions. Each segment or reach of a water- course is rated individually. The rating system will score a reach point total for each side of the water- course. Watercourse types, rating scores and rating criteria are described below. (1) Watercourse Types and Rating Scores. (A) Type 1 watercourse, twenty-one to thirty -three points; (B) Type 2 watercourse, eleven to twenty points; (C) Type 3 watercourse, three to ten points; (2) Watercourse Rating Criteria. (Al Instream Features. (i) Width of watercourse: A measure of the average width of the channel at the ordinary high water mark. (ii) Channel capacity: Quantifies the ability of the channel to convey high flows without flooding. (iii) Channel stability: Measures the stability of the channel by evaluating evidence of bank failure, scour, and downcutting. (iv) Fish use and fish habitat: Anadromous species and resident salmonid need pro- Page 18-36 tection measures if present. Rating depends on the number,of different types of habitat present. (B) Corridor Quality. (i) Width of unmaintained. vegetation: A measure of the width of unmaintained vegetation from the ordinary high water mark. (ii) Vegetation diversity: Quantifies the elements of terrestrial habitat associated with . the watercourse corridor. (ill) Corridor barrier function: Provides some measure of effectiveness of the buffer to limit intrusion and disturbance. (iv) Surrounding land use: Evaluation of the land use immediately outside the vegetated corridor. (e) Areas of Potential Geologic Instability. Areas of potential geologic instability are defined in Section 18.06.050, and are classified as follows: (1) Class 1 areas, where landslide potential is low, and which slope is less than fifteen percent; (2) Class 2 areas, where landslide potential is moderate, which slope is between fifteen and forty percent, and which are underlain by relatively perme- able soils; (3) Class 3 areas, where landslide potential is high, which include areas sloping between fifteen and forty percent, and which are underlain by relatively impermeable soils or by bedrock, and which also include all areas sloping more steeply than forty percent; (4) Class 4 areas, where landslide potential is very high, which include sloping areas with mappable zones of groundwater seepage, and which also include existing mappable landslide deposits regardless of slope; (5) Areas of potential seismic instability, with soft soils, loose sand and a shallow groundwater table. (f) Sensitive Areas Special Studies. (1) Required. An applicant for a development proposal that includes sensitive areas shall submit those studies as required by the City to adequately identify and evaluate the sensitive area and its buffers. (2) Waiver. If there is agreement between the Director of the Department of Community Devel- opment (DCD) and the applicant concerning the sensi- tive area .classification and type, the Director of DCD may waive the requirement for sensitive area studies. There must be substantial evidence that the sensitive. areas classification is correct, that there will be no detrimental impact to the sensitive areas or buffers, and that the goals, purposes, objectives and requirements of this chapter will be followed. (3) Review of Studies. The Department of Community Development will review the informa- tion submitted in the sensitive area studies to verify the information, confirm the nature and type of the sensitive area, and ensure the study 'is consistent with this chapter. TITLE 18 — ZONING (g) When this chapter imposes greater restrictions or higher standards upon the development or use of ' land than other laws, ordinances or restrictive covenants, the provisions of this chapter shall prevail. (h) All other relevant standards of this Code must also be met. (Ord 1608 §7, 1991; Ord. 1599 §3(part), 1991) 18.45.030 Interpretation. The provisions of this chapter shall be held to be minimum requirements in their interpretation and application and shall be liberally construed to serve the purposes of this chapter. (Ord. 1599 §3(part), 1991) 18.45.040 Sensitive area buffers. (a) General. (1) Any land alteration must be located out of the buffer areas as required by this section. Buffers in general are intended to: - (A) Minimize long -term impacts of devel- opment on properties containing sensitive areas; (B) Protect sensitive areas from adverse impacts during development; (C) Preserve the edge of the sensitive area for its critical habitat value; and (D) Prevent loading of potentially unstable slope formations. Land alteration is permitted for public access, supplemental planting and approved land uses as provided in Section 18.45.080. An undisturbed sensitive area or buffer may substitute for the yard setback and landscape requirements of Chapters 18.50 and 18.52. (2) Wetland and watercourse buffers are intended to: (A) Provide shading to maintain stable water temperatures and vegetative cover for additional wildlife habitat; (B) Provide input of organic debris, and uptake of nutrients; (C) Provide an area to stabilize banks, to absorb overflow during high water events, and to allow for slight variation of aquatic system boundaries over time due to hydrologic or climatic effects; (D) Reduce erosion and increased surface water runoff; (E) Reduce loss of or damage to property; (F) Intercept fine sediments from surface water runoff and serve to minimize water quality impacts; .(G) Preserve the edge for its habitat value; and (H) Protect the sensitive area from human and domestic animal disturbance. (3) Buffers for areas of potential geologic instability are intended to: (A) Protect slope stability; Page 18-37 (B) Provide erosion control and attenua- tion of precipitation surface watt and stormwater runoff; t- • - (C) Reduce loss of or damage to property; and (D) Preserve the natural character of wooded hillsides where they exist. (b) Special Buffer Studies. Applicants for a use or development on a legal lot of record within a sensitive area maximum buffer shall be required to conduct a sensitive area study to provide a buffer analysis for the sensitive area. This study may be waived by the Director of the Department of Community Devel- opment (DCD) pursuant to Section 18.45.020(f) (2). (c) Ratings and Buffer Width. Ratings and appro- priate buffers for wetlands and watercourses are listed below. . (1) For wetlands: • (A) Type 1, one - hundred- foot -wide buffer; (B) Type 2, fifty- foot -wide buffer; (C) Type 3, twenty- five - foot -wide_ buffer. (2) For watercourses, the buffer shall be as follows: (A) Type 1, seventy- foot -wide buffer; (B) Type 2, thirty- five - foot -wide buffer; (C) Type 3, fifteen- foot -wide buffer; (3) Setbacks. (A) All commercial and industrial devel- opments shall be set back fifteen feet and all residential development shall be set back ten feet. This setback shall be measured from the foundation to the buffer's edge. (B) The DCD Director may waive setback requirements when a site plan demonstrates there will be no impacts to the buffer zone.(See Figure 18 -4.) (4) Variation of Standard or Creation of Variable Width Wetland/Watercourse Buffers. (A) The DCD Director may reduce the standard wetland /watercourse buffers on a case -by- case basis, provided the buffer does not contain slopes fifteen percent or greater. The approved buffer width shall not result in greater than a fifty percent reduction in width, and the reduced buffer shall not be less than fifteen feet for wetlands and ten feet for watercourses. Any buffer reduction proposal must demonstrate to the satisfaction of the DCD Director that it will not result in direct or indirect, short -term or long -term adverse impacts to wetlands or watercourses, and that (i) The buffer is - vegetated and includes an enhancement plan as may be required to improve the buffer function and value; or (ii) If there is no significant vegetation in the buffer, a buffer may be reduced only if an enhancement plan is provided. The plan must include using a variety of native vegetation that improves the 1. functional attributes of the buffer and provides addi- - tonal protection for the wetland or watercourse func- tions and values. (B) Buffers for all types of wetlands and watercourses will ' increased when they are deter- mined to be partict .. rly sensitive to disturbance or the proposed development will create unusually adverse impacts. Any increase in the width of the buffer shall be required only after completion of a wetland or wa- tercourse study by a qualified wetlands specialist or expert which documents the basis for such increased width. An increase in buffer width may be appropriate when: (i) The development proposal has the demonstrated potential for significant adverse impacts upon the wetland or watercourse which can be miti- gated by an increased buffer width; or (ii) The area serves as habitat for endangered, threatened, sensitive or monitor species listed by the federal government or the State. (C) Every_ reasonable effort shall be made to maintain the existing viable plant life in the buffers. Vegetation may be removed from the buffer as part of an enhancement plan approved by the Director of DCD. Enhancements will ensure that slope stability and wetland and watercourse quality will be maintained or improved. Any disturbance of the buffers for wetlands or watercourses shall be replanted with a diverse plant community of native northwest species that are appropriate for the specific site as determined by the DCD Director. If the vegetation must be removed, or because of the alterations of the landscape the vegeta- tion becomes damaged or dies, then the applicant for a permit must replace existing vegetation along wetlands and watercourses with comparable specimens, approved by the DCD Director, which will reproduce the existing buffer value within five years. (D) The DCD Director shall require subse- quent corrective actions and long -term monitoring of the project if adverse impacts to regulated wetlands, watercourses or their buffers are identified. (d) Areas of Potential Geologic Instability. (1) Each development proposal for a legal lot of record containing an area of potential geologic instability shall be subject to a geotechnical report pursuant to the requirements of Sections 18.45.060 and 18.45.080(e)(4). The geotechnical report shall analyze and make recommendations on the need for and width of any buffers necessary to achieve the goals and requirements of this chapter. Development proposals shall then include the buffer distances as defined within the geotechnical report. (2) Buffers may be increased by the DCD Director when an area is determined to be particularly sensitive to the disturbance created by a development. Such a decision will be based on a City review of the report as prepared by a qualified geotechnical consultant and by a site visit. (Ord 1608 §3, 1991; Ord. 1599 §3(part), 1991) Page 18-38 U. WETLAND BUFFERS Tips 1 -100 foot wide buffer Type 2-50 foot wide buffer Type 3 -25 foot wide butter 10' SETBACK Q • • SINGLE FAMILY /MULTIFAMILY RESIDENTIAL ` : 1.E --Of MARY KOH WATER MARK WATERCOURSE BUFFERS l • Type 1 -70 foot wide buffer • Type 2-35 toot wide buffer '` • 11 Type 3-15 toot wide buffer \ 57TH AVE S. i 1-1 81 -1s .• .••••• •: • .•,�• t •• • • • • • • . •,• • • • • • ••: • • •• ••• •. • • I': • • • : : ••. • .., • • • . • •• •••• :..••• 04 • • • • ••••4 •• . 4 ,•••••• ..••... •r. ••••. • •. :• .44 • • • • . ••• • • • ••• 1.‘• • • • • • • • • • • • • • • ••. • .:: • :0:6. •.••••••••. • . • . . •. • • . • • • • • • • ::•.•• •• • • • • I. • ' • • • • O ti N � 1" =20' SAMPLE RESIDENTIAL SENSITIVE AREA SITE PLAN SUBMITTAL • Figure 18-4 18.45.060 Procedures. 1'then an applicant submits application for any building permit, subdivision, short subdivision or any - other land use review which approves a use, • devel- opment or future construction, the location of any sen- sitive areas and buffers on the site shall be indicated on the plans submitted. When a sensitive area is identi- fied, the following procedures apply. The Director of the Department of Community Development (DCD) may waive item numbers. 1, 2, 4 and 5 of the follow- ing if the size and complexity of the project does not warrant that step in the procedures and the Director grants a waiver pursuant to Section 18.45.020(f)(2). (1) Sensitive Areas Study and Geotechnical Report. The applicant shall submit the relevant study as required in Section 21.04.140 and this chapter. It is intended that sensitive areas studies and information be utilized by applicants in preparation of their proposals and therefore shall be undertaken early in the design stag :3 of a project. - (2) Planned Residential Development Permit. Any new residential subdivision, residential short subdivision, residential boundary line adjustment, or multiple family residential proposal which includes a sensitive area or its buffer on the site shall apply for a planned residential development permit and meet the requirements of Chapter 18.46. (3) Denial of Use or Development. A use or development will be denied if it is determined by the DCD Director that the applicant cannot ensure that potential dangers and costs to future inhabitants of the development, adjacent and local properties, and Tukwila are minimized and mitigated to an acceptable level. (4) Pre - development Conference. The applicant, specialist(s) of record, contractor, and department representatives will be required to attend preconstruction conferences prior to any work on the site. (5) Construction Monitoring. The specialist(s) of record shall be retained to monitor the site during construction. (6) On -site Identification. The DCD Director may require the boundary between a sensitive area and its buffer and any development or use to be permanently identified with fencing, or with a wood or metal sign with treated wood, concrete or metal posts. Size will be determined at the time of permitting, and wording shall be as follows: "Protection of this natural area is in your care. Alteration or disturbance is prohibited pursuant to Section 18.45. Please call the City of Tukwila for more information." (Ord 1608 §4, 1991; Ord. 1599 §3(part), 1991) 18.45.080 Uses and standards. (a) General Uses. The uses set forth in this entire section, including subsections (a) through (h), and the following gene-1 uses, may be located within a sensitive area � buffer, subject to the provisions of Chapter 21.04 and of this section: - (1) Maintenance and repair of existing uses and facilities provided no alteration or additional fill materials will be placed or heavy construction equipment used in the sensitive area or buffer; (2) Nondestructive education and research; (3) Passive recreation and open space; (4) Maintenance and repair of essential streets, roads, rights -of -way, or utilities; (5) Actions to remedy the effects of emergencies that threaten the public health, safety or welfare. (b) Permitted Uses Subject to Administrative Review. The following uses may be permitted only after administrative review and approval by the Director of the Department of Community Develop- ment (DCD): (1) Maintenance and repair of existing uses and facilities where alteration or additional rill r:.ate:ials will be placed or heavy construction equipment used; (2) Construction of new essential streets and roads, rights -of -way and utilities; (3) New surface water discharges to wetlands or watercourses or their buffers from detention facilities, presettlement ponds or other surface water management structures may be allowed provided that the discharge meets the clean water standards of RCW 90.48 and WAC 173.200 and 173.201 as amended, and does not increase the rate of flow to the wetland or watercourse beyond the level of the existing rate; (4) Regional stormwater detention areas may be allowed if use results in no decrease in rating of resource and enhances existing values and functions. Design shall be subject to the standards of this section and other applicable City standards; (5) Enhancement or other mitigation including landscaping. (c) Wetlands. (1) General. (A) No use or development may occur in a Type 1 and Type 2 wetland or its buffer except as specifically allowed by subsections (a), (b) and (h) of this section. Any use or development allowed is subject to the standards of this section. (B) Only isolated Type 3 wetlands can be altered or relocated, and then only with the permission of the DCD Director. A mitigation or enhancement plan must be developed and must comply with the standards of compensatory mitigation required in this chapter. (C) Mitigation plans shall be completed for any proposals for dredging, filling, alterations and relocation of wetland habitat allowed in subsections (a), (b) and (h) of this section. Page 18-39 (2) Compensatory Mitigation. • ,(A) The mitigation plan shall be developed as part of a sensitive area study by a specialist approved by the DCD 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 this chapter and show how water quality, wildlife and fish habitat, and general wetland quality would be improved. (B) In order to achieve the City's goal of no net loss of wetland functions and acreage, alteration of wetlands will require the applicant to provide a restoration, enhancement or creation plan to compen- sate for the impacts to the wetland and will compen- sate at a ratio of 1.5 to 1. (C) Mitigation Location. (i) On -site compensation shall be provided, except where the applicant can demonstrate that a. The hydrology and ecosystem of the original wetland and those who benefit from the hydrology and ecosystem will not be damaged by the on -site loss; and b. On -site compensation is not scientifically feasible due to problems with hydrology, soils, waves or other factors; or c. Compensation is not practical due to potentially adverse impact from surrounding land uses; or d. Existing functional values at the site of the proposed restoration are significantly greater than lost wetland functional values; or e. That established regional goals for flood storage, flood conveyance, habitat or other wetland functions have been established and strongly justify location of compensatory measures at another site. (11) Off -site compensation shall occur within the same watershed where the wetland loss occurred. (iii) In selecting compensation sites, applicants shall pursue siting in the following order of preference: a. Upland sites which were for- merly wetlands: b. Idled upland, sites generally having bare ground or vegetative cover consisting primarily of exotic introduced species, weeds or emergent vegetation; c. Other disturbed upland. (D) Mitigation Standards. The scope and content of a mitigation plan shall be decided on a case - by -case basis. As the impacts to the sensitive area increase, the mitigation measures to offset these impacts will increase in number and complexity. The components of a complete wetlands mitigation plan are as follows: (1) Baseline information of quantita- tive data collection o: a review and synthesis of exist- ing data for both the project impact zone and the proposed mitigation site; (ii) Environmental goals and objec- tives that describe the purposes of the mitigation 'measures. This should include a description of site - selection criteria, identification of target evaluation species and resource functions; (iii) Performance standards of the spe- cific 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; (iv) Detailed construction plan of the written specifications and descriptions of mitigation techniques. This plan should include the proposed construction sequence and construction management, and be accimpanied by detained site diagrams and blueprints that are an integral requirement of any development -oposal; (v) Monitoring and /or evaluation pro- gram 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; (vi) Contingency plan identifying potential courses of action, and any corrective measures to be taken when monitoring or evaluation indicates project performance standards have not been met; (vii) Performance security or other assurance devices as described in Section 18.45.135. (E) Mitigation Timing. Where feasible, compensatory mitigation projects shall be completed prior to activities that will permanently disturb wet- lands and immediately after activities that will temporarily disturb wetlands. Construction of com- pensatory projects shall be timed to reduce impacts to existing wildlife, flora and water quality, and shall be completed prior to use or occupancy of the activity or development. (3) Essential Utilities. (A) Essential utilities must be constructed to minimize or, where possible, avoid wetland distur- bance. (B) All construction must be designed to protect the wetland and its buffer against erosion, uncontrolled drainage, restriction of groundwater movement, slides, pollution, habitat disturbance, any loss of flood carrying and storage capacity, and excava- tion or fill detrimental to the environment. {C) Upon completion of installation of essential utilities, wetlands must be restored to pre- Page 18-40 ' project configuration, replanted as - required and provided with maintenance car( ztil -newly planted vegetation is established. (D) All crossings must be designed for shared facilities in order to minimize adverse impacts and reduce the number of crossings. (4) Essential Streets, Roads and Rights-of-Way. (A) Essential streets, roads and rights -of- way must be designed and maintained to prevent erosion and avoid restricting the natural movement of groundwater. (B) Essential streets, roads and rights -of- way must be located to conform to the topography so that minimum alteration of natural conditions is neces- sary. The number of crossings shall be limited to those necessary to provide essential access. (C) Essential streets, roads and rights -of- way must be constructed in a way which does not adversely affect the hydrologic quality, of the wetland or interrelated stream habitat. Where feasible, crossings must allow for combination with other essential utilities. (D) Upon completion of construction, the area affected must be restored to an appropriate grade, replanted according to a plan approved by the Director of DCD, and provided with care until newly - planted vegetation is established. (5) Public Use and Access. (A) Public access shall be limited to trails, boardwalks, covered or uncovered viewing or seating areas and displays, and must be located in areas which have the lowest sensitivity to human disturbance or alteration, and (B) Public access must be specifically developed for interpretive, educational or research purposes by, or in cooperation with, the City or as part of the adopted Tukwila Parks and Open Space Plan. (C) No motorized vehicle is allowed within a wetland or its buffer except as required for necessary maintenance, agricultural management or security. (D) Any public access or interpretive displays developed in a wetland and its buffer must, to the extent possible, be connected with a park, recreation or open -space area. - (E) Vegetative edges, structural barriers, signs or other measures must be provided wherever .necessary to protect sensitive areas by limiting access to designated public use or interpretive areas. (F) Access trails must incorporate design features and materials which protect water quality and allow adequate surface water and groundwater movement. (G) Access trails must be located where they do not disturb nesting, breeding, and rearing areas and buffer areas, and must be designed so that sensitive plant and critical wildlife species are protected. (6) Dredging, Digging or Filling. (A) edging, digging or filling within a wetland and itsuffer may occur only with the per- mission of the DCD Director and only for the following purposes: (i) Uses permitted by subsections (a), (b) and (h) of this section; or (11) Maintenance of an existing wet- land; or (iii) Enhancement or restoration of habitat in conformance with an approved mitigation plan identified in a sensitive area study; or (iv) Natural system interpretation, education or research when undertaken by, or in cooperation with, the City; or (v) Flood control or water quality enhancement by the City; or (vi) Maintenance of existing water quality controls, for normal maintenance needs and for any - diversion, rerouting, piping or other alteration permitted by this chapter. (B) Any dredging, digging or filling shall be performed in a manner which will minimize sedi- mentation in the water. Every effort will be made to perform such work at the time of year when the impact can be lessened. (C) Upon completion of construction, the area affected must be restored to an appropriate grade, replanted according to a plan approved by the Director of DCD and provided with care until newly - planted vegetation is established. (d) Watercourses. (1) General. (A) No use or development may occur in a watercourse or its buffer except as specifically allowed by this section. Any use or development allowed is subject to the standards of this section. (B) Diverting or rerouting may only occur with the permission of the DCD Director and an approved mitigation plan. (C) Any watercourse which has critical wildlife habitat, or is necessary for the life cycle or spawning of salmonids, shall not be rerouted unless it can be shown that the habitat will be improved for the benefit of the species. - (D) Any watercourse which has no criti- cal wildlife habitat may be rerouted if the waters flowing from the new configuration can be shown to do so in a manner that does not in any way adversely affect the habitat of a downstream salmonid- bearing water. (2) Mitigation. (A) Plans. Mitigation plans shall be com- pleted for any proposals of dredging, filling, diverting and rerouting of watercourses. Page 18-41 TUKWILA MUNICIPAL CODE, .03) Plan Contents. The mitigation plan shall be developed as part of a sensitive area study by a specialist approved by the DCD Director. The plan must show how water quality, treatment, erosion control, pollution reduction, wildlife and fish habitat, and general watercourse quality would be maintained or improved. All such plans must be approved by the DCD Director. (C) Mitigation Standards. The scope and content of a mitigation plan shall be decided on a case - by -case basis. As the impacts to the sensitive area increase, the mitigation measures to offset these impacts will increase in number and complexity. The components of a complete mitigation plan are as follows: (i) 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; - (ii) 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 resource functions; (iii) 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. The following shall be considered the minimum performance standards for approved stream alterations: a. Maintenance or improvement of stream channel dimensions, including the components of depth, width, length and gradient of the original location, b. Bank and buffer configuration should be restored to an equal or enhanced state of the original stream, c. The channel, bank and buffer areas shall be replanted with native vegetation which replicates or improves the original in species, sizes and densities, d. The stream channel bed and the biofiltration systems shall be equivalent to or better than in the original stream, • e. The original fish and wildlife habitat shall be maintained or enhanced, f. Relocation of a watercourse shall not result in the new sensitive area or buffer extending beyond the development site and onto adjacent property without the agreement of the affected property owners, g A watercourse may be rerouted; (iv) Detailed construction plan of the written - specifications and 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; (v) 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 process; • (vi) Contingency plan identifying potential courses of, action, and any corrective measures to be taken when monitoring or evaluation indicates project performance standards have not been met; - - (vii) Performance security or other assurance devices a: described in. Section 18.45.135. (D) Mitigation Timing. DCD - approved plans must have the mitigation construction completed before the .existing watercourse can be modified. (3) Essential Utilities. (A) Essential utilities must be constructed to minimize, or where possible avoid, disturbance of the watercourse and its buffer. (B) All construction must be designed to protect the watercourse and its buffer against erosion, uncontrolled drainage, restriction of groundwater movement, slides, pollution, habitat disturbance, any loss of flood carrying capacity and storage capacity, and excavation or fill detrimental to the environment. (C) Upon completion of installation of essential utilities, watercourses and their buffers must be restored to pre - project configuration, replanted as required and provided with maintenance care until newly planted vegetation is established. (D) All crossings must be designed for shared facilities in order to minimize adverse impacts and reduce the number of crossings. (4) Essential Streets, Roads and Rights -of -Way. (A) Essential streets, roads and rights -of- way must be designed and maintained to prevent erosion and avoid restricting the natural movement of groundwater. (B) Essential streets, roads and rights -of- way must be located to conform to the topography so that minimum alteration of natural conditions is necessary. The number of crossings shall be limited to those necessary to.provide essential access. (C) Essential streets, roads and rights -of- way must be constructed in a way which does not adversely affect the hydrologic quality of the watercourse and its buffer. Where feasible, crossings must allow for combination with other essential utilities. (D) Upon completion of construction, the area affected must be restored tr .. appropriate grade, replanted according to a plan aproved by the Director of DCD, and provided with care until newly - planted vegetation is established. (5) Public Use and Access. (A) Public access shall be limited to trails, boardwalks, covered or uncovered viewing and seating areas, and displays and must be located in areas which have the lowest sensitivity to human disturbance or alteration. (B) public access must be specifically developed for interpretive, educational or research purposes by, or in cooperation with, the City or as part of the adopted Tukwila Parks and Open Space Plan. (C) No motorized vehicle is allowed within a watercourse or its buffer except as required for necessary maintenance, agricultural management or security. (D) Any public access -or interpretive dis- plays developed along a watercourse and- its buffer must, to the exten•possible, be connected with a park, recreation or open -space area. (E) Vegetative edges, structural barriers, signs or other measures must be provided wherever necessary to protect watercourses and their buffers by limiting access to designated public use or interpretive areas. (F) Access trails must incorporate design features and materials which protect water quality and allow adequate surface water and groundwater movement. (G) Access trails must be located where they do not disturb nesting, breeding and rearing areas and must be designed so that sensitive plant and critical wildlife species are protected. (6) Piping. (A) Piping of any watercourse should be avoided. Piping may be allowed in any watercourse if it is necessary for access purposes. Piping may be allowed in Type 3 watercourses if the applicant com- plies with the conditions of this section, including: (i) Providing excess capacity to meet needs of the system during a one - hundred -year flood event; and (ii) Providing flow restrictors, and complying with water quality and existing habitat - enhancement procedures. (B) No process that *requires maintenance on a regular basis will be acceptable unless this main- tenance process is part of the regular and normal facilities maintenance process or unless the applicant can show funding for this maintenance is ensured. (C) Piping in a watercourse sensitive area shall be limited and shall require approval of the DCD Director. Piping projects shall be performed pursuant to the following applicable standards: ( The conveyance sys designed to col._ / with the standards i and recommended by the Departme Works. (ii) Where allowed, pip limited to the shortest length possible as d the Director of DCD to allow access onto a (iii) Where water is piped point, those driveways or entrances shal dated to serve multiple properties where to minimize the length of piping. (iv) When required by th DCD, watercourses under drivable surf contained in an arch culvert using overs span culverts for rebuilding of a strea shall be provided with check dams to and shall be replanted and enhanced accor approved by the Director of DCD. (v) When necessary to fish passage, fish ladders shall be one -foo to ten -foot horizontal distance, or as app State Department of Fisheries. (vi) Stormwater runoff tained and infiltrated to preserve the channel's dominant discharge. (vii) All construction shall to have the least adverse impact on the buffer and surrounding environment. (viii) Piping shall be during periods of low flow, or as specifie Department of Fisheries. (ix) Water quality must better for any water exiting the pipe as entering the pipe, and flow must be com (7) Dredging, Digging or Filling. (A) . Dredging, digging or filling within a watercourse or its buffer may occur o 1y with the permission of the DCD Director and my for the following purposes: (i) Uses permitted by Section em shall be current use t of Public ng shall be termined by property. for an access be consoli- ossible, and Director of ces shall be ze or super - ed. These educe flows, ing to 2 plan provide for vertical rise oved by the hall be de- watercourse be designed watercourse, constructed by the State e as good or or the water arable. 18.45.080; (ii) Maintenance of an e course; sting water- (iii) Enhancement or r storation of habitat in conformance with an approv d mitigation plan identified in a sensitive area study; (iv) Natural system interpretation, education or research when undertak n by, or in cooperation with, the City; (v) Flood control or ater quality enhancement by the City; . (vi) Maintenance of e listing water quality controls, for normal maintenance eeds and for any diversion, rerouting, piping or o er alteration permitted by this chapter. Page 18-43 TUKW ILL. MUNICIPAL CODE (B) Any dredging, digging or filling shall be performed in a manner which will minimize sedi- mentation in the water. Every effort will be made to perform such v,Tork at the time of year when the impact can be lessened. (C) Upon completion of construction, the area affected must be restored to an appropriate grade, replanted according to a plan approved by the Director of DCD, and provided with care until newly- planted l.egetation established. (e) Areas of Potential Geologic Instability. (1) General. The uses permitted in the under- lying zoning district may be undertaken on sites which contain areas of potential geologic instability subject to the standards of this section and the requirements of a geotechnical study. (2) Exemptions. Any temporary slope which has been created through legal grading activities may be regraded without application of this chapter under an approved permit. (3) Alterations. - (A) Prior to permitting alteration of an area of potential geologic instability, the applicant must demonstrate one of the following: (1) There is no evidence of past insta- bility or earth movement in the of the proposed development, and quantitative analysis of slope stability indicates no significant risk to the proposed development or surrounding properties; or (ii) The area of potential geologic in- stability can be modified or the project can be designed so that any potential impact to the project and surround- ing properties is eliminated, slope stability is not decreased, and the increase in surface water discharge or sedimentation shall not decrease slope stability. (B) Where any portion of an area of poten- tial geologic instability is cleared for development, a landscaping plan for the site shall include tree replanting with an equal mix of evergreen and deciduous trees, preferably native, and approved by the Director of DCD. Replacement vegetation shall be sufficient to provide erosion and stabilization protection. (4) Geotechnical Report. • (A) The applicant shall submit a geotech- nical report appropriate to both the site conditions and the proposed development. A geotechnical investiga- tion shall be required for development in Class 2, Class 3, Class 4 areas, and any areas identified as seismic or Coa' Mine Hazard Areas unless waived pursuant to Section 18.45.020(f) (2). (B) Geotechnical reports for Class 2 areas shall include at a minimum a site evaluation review of available information regarding the site and a surface reconnaissance of the site and adjacent areas. Subsurface exploration of site conditions is at the discre- tion of the geotechnical consultant. (C) Geotechnical reports fcr Class 3, Class 4 and Coal Mine Hazard Areas shall include a site evaluation review of available information about the site, a surface reconnaissance of the site and adjacent areas, and a subsurface exploration of soils and hydrol- ogy conditions. Detailed slope stability analysis shall be done if the geotechnical consultant recommends it in Class 3 or Coal Mine Hazard Areas, and must be done in Class 4 areas. (D) Seismic hazard areas shall include an evaluation of site response and liquefaction potential for the proposed development area. For one -story or two- story single- family dwellings, this evaluation may be based on the performance of similar structures under similar foundation conditions. For proposed develop- ments including occupied structures other than one - story and two-story single - family dwellings, the eval- uation shall include sufficient subsurface exploration to provide a site coefficient (S) for use in the static lateral force procedure described in the Uniform Building Code. (E) Applicants shall retain a geotechnical engineer to prepare the reports and evaluations required in this subsection. The geotechnical report and completed site evaluation checklist shall be prepared in accordance with the generally accepted geotechnical practices, under the supervision of and signed and stamped by the geotechnical engineer. The report shall be prepared in consultation with the appro- priate City department. Where appropriate, a geologist must be included as part of the geotechnical consulting team. The report shall make specific recommenda- tions concerning development of the site. (F) The geotechnical engineers required under this subsection must meet the qualification stan- dards approved by the Director of DCD. Applicants shall provide a list of qualifications of the firm or individuals who will be doing the technical studies, and those shall be approved by the Director of DCD. If the engineers' credentials are not sufficient, the City may require applicants to use a different engineer or firm which does meet the City's standards. (G) The opinions and recommendations contained in the report shall be supported by field observations and, where appropriate or applicable, by literature review conducted by the geotechnical engineer which shall include appropriate explorations, such as borings or test pits, and an analysis of soil characteristics conducted by or under the supervision of the engineer in accordance with standards of the American Society of Testing and Materials or other applicable standards. If the evaluation involves geologic evaluations or interpretations, the report shall be reviewed and approved by a geologist. (H) An independent review of geotechni- cal reports will be required per Section 21.04.140. (5) Disclosures, Declarations and Covenants. (A) It shall be the: >ponsibility of the applicant to submit, consistent vu -i the findings of the geotechnical report, structural plans v, hich were pre- pared and stamped by a structural engineer. The plans and specifications shall be accompanied by a letter from the geotechnical engineer who prepared the geotechni- cal report stating that in his /her judgment, the plans and specifications conform to the recommendations in the geotechnical report; the risk of damage to the pro- posed development site from soil instability will be minimal subject to the conditions set forth in the report; and the proposed development will not increase the potential for soil movement. (B) Further recommendations signed and sealed by the geotechnical engineer shall be provided should there be additions or exceptions to the original recommendations based on the p'.ans, site conditions or other supporting data. If the geotechnical engineer who reviews the plans and specifications is not the same engineer who prepared the geotechnical report, the new engineer shall, in a letter to the City accom- panying the plans and specifications, express his or her agreement or disagreement with the recommenda- tions in the geotechnical report and state that the plans and specifications conform to his or her recommenda- tions. (C) The architect or structural engineer shall submit to the City, with the plans and specifica- tions, a letter of notation on the design drawings at the time of permit application stating that he or she has reviewed the geotechnical report, understands its recommendations, has explained or has had explained to the owner the risks of loss due to slides on the site, and has incorporated into the design the recommenda- tions of the report and established measures to reduce the potential risk of injury or damage that might be caused by any earth movement predicted in the report. (D) The applicant, or the owner of the site if the applicant is not the owner, shall submit a letter to the City, with the plans and specifications, stating that he or she understands and accepts the risk of develop- ing in an area with potential unstable soils and that he or she will advise, in writing, any prospective purchasers of the site, or any prospective purchasers of structures or portions of a structure on the site, of the slide potential of the area. (E) The owner shall execute a covenant, running with the land, on a form provided by the City. The City will file the completed covenant with the King County Department of Records and Elections at the expense of the applicant or owner. A copy of the recorded covenant will be forwarded to the owner. This covenant shall include: (1) The legal description of the prop- erty; (11) A statement a. Explaining that the site is in an area of potential . tability, b. Of the risks associated with development on the site, c. Of any conditions or prohibi- tions on development, and d. Of any features in this design which will require maintenance or modification to address anticipated soil changes; (iii) A statement waiving any claims the owner or his /her successors or assigns may have against the City for any loss or damage to people or property, either on or off the site, resulting from soil movement arising out of the issuance of any permit(s) authorizing development on the site; (iv) The date of issuance and number of the permit authorizing the development. (6) Assurance Devices. Whenever the City determines that the public interest would nct be served by the issuance of a permit in an area of poten- tial geologic instability without assurance of a means of providing for restoration of areas disturbed by, and repair of property damage caused by, slides arising out of or occurring during construction, the DCD Director may require assurance devices pursuant to Section 18.45.135. (7) Construction Monitoring. (A) The applicant shall retain a geotechni- cal engineer to monitor the site during construction. The applicant shall preferably retain the geotechnical engineer who prepared the final geotechnical recom- mendations and reviewed the plans and specifications. If a different consultant is retained by the owner, the new geotechnical engineer shall submit a letter to the City stating whether or not he /she agrees with the opinions and recommendations of the original geotechnical engineer. Further recommendations, signed and sealed by the geotechnical engineer, and supporting data shall be provided should there be exceptions to the original recommendations. (B) The geotechnical engineer shall moni- tor, during construction, compliance with the recom- mendations in the geotechnical report, particularly site excavation, shoring, soil support for foundations includ- ing piles, subdrainage installations, soil compaction and any other geotechnical aspects of the construction. Unless otherwise approved by the City, the specific recommendations contained in the soils report must be implemented by the owner. The geotechnical engi- neer shall make written, dated monitoring reports on the progress of the construction to the City at such timely intervals as shz11 be specified. Omissions or deviations from the approved plans and specifications shall be immediately reported to the City. The final construction monitoring report shall contain a statement from the geotechnical engineer that, based upon his or her professional opinion, site observations and testing during the monitoring of the construction, the Page 18-45 TUKWILA MUNICIPAL CODE • complete•i •development substantially complies with the recommendations in the geotechnical report and with all geotechnical- related permit requirements. Occupancy of the project will not be approved until the report has been reviewed and accepted by the DCD Director. (8) Conditioning and Denial of Use or Devel- opments. (A) Substantial weight shall be given to ensuring continued slope stability and the resulting public health, safety and welfare in determining whether a development should be allowed. (B) The City may impose conditions that address site -work problems which could include, but are not limited to, limiting all excavation and drainage installation to the dryer season, or sequencing activities such as installing erosion control and drainage systems well in advance of construction. A permit will be denied if it is determined by the DCD Director that the development will increase the potential of soil move- ment that results in an unacceptable risk of damage to the proposed development, its site or adjacent proper- ties. (f) Abandoned Mine Areas. (1) Development of a legal lot of record con- taining an abandoned coal mine area may be permitted when a geotechnical report shows that significant risks associated with the abandoned mine workings can be eliminated or mitigated so that the site is safe. Approval shall be obtained from the DCD Director before any building or land - altering permit processes begin. (2) Any building setback or land alteration shall be based on the geotechnical report. (3) The City may impose conditions that address site -work problems which could include, but are not limited to, limiting all excavation and drainage installation to the dryer season, or sequencing activities such as installing drainage systems or erosion controls well in advance of construction. A permit will be denied if it is determined that the development will increase the potential of soil movement or result in an unacceptable risk of damage to the proposed develop- ment or adjacent properties. (g) Areas of Important Geological or Archaeologi- cal Evidence. (1) Development on a legal lot of record determined to have historic or prehistoric geological or archaeological evidence, shall be prohibited until that evidence has been studied or researched for any valu- able information about our history. Removal or salvage of the evidence shall be done in accordance with RCW 27.53, and shall be performed in a timely manner. (2) Once the geologic or archaeological evi- dence or articles have been studied or researched, or the importance of the site is declared to be marginal or not of use to the scientific community, development shall be allowed on the site. Development shall not begin on such a site until the DCD Director gives approval. (h) Permitted Uses Subject to Exception Approval. Other uses may be permitted upon receiving a reason- able use exception pursuant to Section 18.45.115. A use permitted through a reasonable use exception shali conform to the procedures of this chapter and be consistent with the underlying zoning. (Ord. 1608 §,§7, 5, 1991; Ord. 1599 §3(part), 1991) 18.45.090 Sensitive areas tracts. (a) In development proposals for planned resi- dential or mixed area use developments, short subdi- visions or sub'divisions, and boundary line adjustments and binding site plans, applicants shall create sensitive areas tracts, in lieu of an open space tract, per the standards of Section 18:46.080. (b) Applicants proposing development involving uses other than those listed in subsection (a) of this section, on parcels with sensitive areas or their buffers, may elect to establish a sensitive areas tract which shall be: (1) If under one ownership, owned and main - tained by the ownership, which protection of the trac,; (2) Held in common ownership by multiple owners who shall collectively be responsible for main- tenance of the tract; or (3) Dedicated for public use if acceptable to the City or other appropriate public agency. (Ord 1599 §3 (part), 1991) 18.45.115 Exceptions. (a) General. With the approval of the Director of DCD, isolated wetlands that are four hundred square feet or smaller in area, and which are low in value according to the rating methodology used in the City's Water Resource Rating and Buffer Study, may not require the compensatory mitigation standards of this chapter. (b) Piping. Piping will be allowed in Type 1 and Type 2 watercourses only where relocation or alter- ation of a watercourse is denied and would result in denial of all reasonable use. (c) Reasonable Use Exceptions. (1) If application of this chapter would deny all reasonable use of the property containing wetlands, watercourses or their buffers, the property owner or the proponent of a development proposal may apply for a reasonable use exception. (2) The application for a reasonable use excep- tion shall be in a format specified by and filed with the Department of Community Development (DCD). Requirements may include an environmental impact statement pursuant to WAC 197 -11 -400. Reasonable use exceptions shall be decided by the planning com- mission following a public hearing noticed as specified in Chapter 18.92: (3; If the applicant dem—strates to the satisfac- tion of.the Planning Commissia,_ .nat application of the provisions of this chapter would deny all reasonable - use of the property, development may be allowed which is consistent with the general purposes of this chapter and the public interest (4) The Commission, in granting approval of the reasonable use exception, must determine that: (A) No reasonable use with less impact on the sensitive area and its buffer is possible; (B) There is no feasible on -site alternative to the proposed activities, including reduction in size or density, phasing of project implementation, change in timinv activities, revision of road and lot layout, and/or relatui site planning activities that would allow a reasonable economic use with fewer adverse irr:zacts to the sensitive area and its buffer; (C) As a result of the proposed develop- ment there will be no increased or unreasonable threat of damage to off -site public or private property and no threat to the public health, safety or welfare on or off the development proposal site; (D) Alterations permitted shall be the minimum necessary to allow for reasonable use of the property; (E) The proposed development is compat- ible in design, scale and use with other development with similar site constraints in the immediate vicinity of the subject property; (F) Disturbance of sensitive areas has been minimized by locating the necessary alterations in the buffers to the greatest extent possible; (G) The inability to derive reasonable use of the property is not the result of actions by the appli- cant in segregating or dividing the property and creating the undevelopable condition after the effective date of the ordinance from which this chapter derives; and (H) Any approved alteration of a sensitive area under this section shall be subject to conditions as established by this chapter and will require mitigation under an approved mitigation plan. If a development is approved as a reasonable use, the Board of Architectural Review's process, review and standards shall be applied. (Ord. 1599 §3(part), 1991) 18.45.120 Variances. (a) The Board of Adjustment shall review requests pursuant to Chapter 18.72 for variance from the standards of this chapter unless excepted by Section 18.45.115. (b) If a variance is granted, it shall be the mini- mum necessary to accommodate the permitted uses of the underlying zoning districts proposed by the appli- cation, and the scale of the use may be reduced as necessary to meet this requirement. (Ord 1599 §3(part), 1991) 18.45.125 Apt 's. .(a) Anyb;rieved party who objects to or dis- agrees with Department of Community Development (DCD) decisions or conditions for development in a sensitive area shall appeal to the Planning Commis- sion. Any such appeal shall be made in writing within ten days of the interpretation, condition or decision being appealed, and shall set forth the basis for the appeal. (b) In considering appeals of decisions or condi- tions, the following shall be considered: (1) The intent and purposes of the sensitive areas ordinance from which this chapter derives; (2) Technical information and reports consid- ered by the Department of Community Development; and (3) Findings of the DCD Director which shall be given substantial weight. (Ord. 1599 §3(part), 1991) ¶8.45:130 Recording required. The property owner receiving approval of a use or development pursuant to this chapter shall record the City- approved site plan clearly delineating the wetland, watercourse, areas of potential geologic instability or abandoned mine and their buffers designated by Sections 18.45.020 and 18.45.040 with the King County Division of Records and Elections. The face of the site plan must include a statement that the provisions of this chapter, as of the effective date of the ordinance from which this chapter derives or thereafter amended, control use and development of the subject property, and provide for any responsibility of the property owner for the maintenance or correction of any latent defects or deficiencies. (Ord. 1599 §3(part), 1991) 18.45.135 Assurance device. (a) In appropriate circumstances, the Director of the Department of Community Development may require a letter of credit or other security device accept- able to the city, to guarantee performance and mainte- nance requirements of this chapter. All assurances shall be on a form approved by the City Attorney. (b) When alteration of a sensitive area is approved, the Director of the Department of Commu- nity Development may require an assurance device, on a form approved by the City Attorney, to cover the monitoring costs and correction of possible deficiencies. Monitoring of alterations may be required for up to fiv•: years. (c) Release of the security does not absolve the property owner of responsibility for maintenance or correcting latent defects or deficiencies. (Ord 1599 53 (part), 1991) Page 18-47 TUKWILA MUNICIPLL CODE C 18.45.140 Assessment relief. (a) Fair Market Value. The King County-Assessor shall consider sensitive area regulations in determining the fair market value of land under RCW 84.34. (b) Current Use Assessment. Established sensi- tive area tracts, as defined in Section 18.06.698 and provided for in Section 18.45.090, shall be classified as open space and owners thereof may qualify for current use taxation under RCW 18.34; provided, such landowners have not received density credits, or set - back or lot size adjustments as provided in Chapter 18.46. (c) Special Assessments. Landowners who qualify under subsection (b) of this section shall also be exempted from special assessments on the sensitive area tract to defray the cost of municipal improvements such as sanitary sewers, storm sewers and water mains. (Ord. 1599 §3(pa: t), 1991) Chapter 18.46 PRD — PLANNED RESIDENTIAL DEVELOPMENT Sections: 18.46.010 Purpose. 18.46.020 Permitted districts. 18.46.030 Permitted uses. 18.46.040 Site acreage minimum. 18.46.060 Relationship of this chapter to other sections and other ordinances. 18.46.070 Density standards. 18.46.080 Open space. 18.46.090 Relationship to adjacent areas. 18.46.100 Preapplication procedure. 18.46.110 Application procedure required for PRD approval. 18.46.112 Review criteria. 18.46.115. Restrictive covenants subject to approval - - by City Council anu City Attorney. 18.46.120 Application procedures for building permit. 18.46.130 Minor and major adjustments. 18.46.140 Expiration of time limits. 18.46.010 Purpose. It is the purpose of this chapter to encourage imagi- native site and building design and to create open space in residential developments by permitting greater flexibility in zoning requirements than is permitted by other sections of this title. Furthermore, it is the pur- pose of this chapter to: (1) Promote the retention of significant features of the natural environment, including topography, vegetation, waterways, wetlands and views; (2) Encourage a variety or mixture of housing types; (3) Encourage maximum efficiency in the layout of streets, utility networks, and other public improvements; and (4) Create and /or preserve usable open space for the enjoyment of the occupants and the general public. (Or. 1599 §4(1), 1991; Ord 1247 §I(part), 1982) 18.46.020 Permitted districts. Planned residential development (PRD) may be permitted in the following districts: (1) R -1, Single -family residential; (2) R -2, Two - family residential; (3) R -3, Three- and four - family residential; (4) R -4, Low apartments; (5) RMH, Multiple- residence high density. (Ord. 1289 §l, 1983: Ord. 1247 §!(part), 1982) City of Tukwila John W. Rants, Mayor July 17, 1992 Department of Community Development Rick Beeler, Director Leroy Lowe A.I.A. Architects P.O. Box 1241 Seattle, WA 98111 Subject: Hillcrest 90- 13- BLA/91 -3 -APRD Dear Mr. Lowe: This letter is to recap the two meetings we have had and your letters of June 15, 1992 and June 29, 1992. To date you have filed an application for a Boundary Line Adjustment (BLA) and Administrative Planned Residential Development (APRD). You have also requested a Reasonable Use Exception (RUE) from the Sensitive Areas Ordinance (SAO). The letter is divided in three sections; the Boundary Line Adjustment, Reasonable Use Exception (June 15, 1992 letter), and Response To June 29, 1992 Letter. BOUNDARY LINE ADJUSTMENT /ADMINISTRATIVE PLANNED RESIDENTIAL DEVELOPMENT: As mentioned at our last meeting, you have three options in developing your property. The first option is proceeding ahead with the Boundary Line Adjustment which requires the following development issues to be addressed: WETLANDS: * The wetland delineation work, completed by your wetland consultant with assistance by the city's Urban Environmentalist, has determined total sizes and configurations of the wetland areas. Specific wetland boundary revisions included additional flagging for Wetland A and the delineation of Wetland D. * The current wetland boundaries are verified; however, the additional flagging of Wetland A will need to be surveyed prior to the completion of this project. Page 2 * Because all on -site wetlands are less than 1.0 acres in area and have less than three wetland classes, they are rated as Type 3. The standard buffer width for Type 3 wetlands is 25 feet. A 15 -foot minimum buffer may be allowed with an approved buffer enhancement plan. Due to its small size, Wetland D is exempt from regulation. * Until a peer review /geotechnical study is completed, the city's position on wetland use is to preserve the northern half of the wetland area. This portion of the site has the most significant groundwater discharge. * With the exception of Wetland D, wetland mitigation is required for all regulated wetlands. Any proposed alteration to the on -site Type 3 wetlands must include a wetland mitigation plan. To review a wetland alteration proposal, mitigation measures should be proposed as a conceptual plan for identifying potential impacts and providing adequate replacement of wetland area and function. SETBACKS: * Identify setbacks on the site plan. All setbacks under the APRD may be reduced with DCD Director's approval. (Section 18.46.060(a)(3).) PUBLIC FACILITIES: * Downstream drainage facilities (including WSDOT) of this development lack capacity for any added surface or subsurface discharges. Therefore, this development is restricted to on -site detention facilities that reduce discharge rates. * The existing water system provides limited capacity to serve your development. A looped system is necessary to provide reliable fire /domestic flows for the intended use. You need to work with Highline Water District (Jay Gibson) to obtain any joint funding for the required public water main in 53rd Ave. S. This will tie the existing systems at Slade Way and S. 160 Street together. At the meeting the Highline Water representative was agreeable to presenting the joint funding (cost sharing) concept to his commissioners. * Water & sewer availability letters need to be included in your submittal and be based on the final lot configuration. * If any utilities, access areas, or preserved wetlands /springs require easements across lot lines in the new reconfigured lot line proposal, these easements must be shown as part of the submittal. At the June 3, 1992 meeting, staff explained that the City would conduct a peer review of your geo- technical /hydrological reports after you had revised your boundary line proposal. Page 3 However, at the meeting on June 23, 1992, you explained that given the safety issue, you believe no changes in the proposal were needed. Given your concerns, the City is moving up the time frame for the peer review. The peer review scope of work will include risk assessment for the potential to develop portions of your property while maintaining on -site and off -site stability. Public Works estimates the peer review should be completed in eight to ten weeks. In conjunction with the peer review, the city needs a letter stating your geotech has reviewed the most current proposal and findings of his soil reports As noted at our last meeting, your second option is to withdraw your application and request building permits for the lots of record. The lots of record need to provide the front, side and rear yard requirements as well as other applicable dimensional standards in the Zoning Code. The last option recommended to you was to retain the BLA and wait for the results of the peer review study before requesting Reasonable Use Exception. REASONABLE USE EXCEPTION: On June 15, 1992, you submitted material .requesting a Reasonable Use Exception under Section 18.45.115 of the Zoning Code (SAO). Upon reviewing the Uses and Standards criteria, staff believes your application has not addressed 18.45.080 C.1 b. and c. Specifically, you have not submitted a proposal to mitigate for potential wetland loss and impacts. Without the peer review study findings, the application of the Uses and Standards section cannot be waived by the Planning Commission until it finds that the criteria under 18.45.115 (Exceptions) have been met. It is not clear that "the application of this chapter would deny all reasonable use of the property" (18.45.115 C. 1.) Staff is concerned that moving ahead now with the Reasonable Use Exception will further delay you in your efforts to develop your property. As noted at the last meeting, staff wishes to assist you with solutions to develop this very sensitive property in a timely manner. The July 23, 1992 Planning Commission schedule is full. However, I have requested the Planning Commission to hold a special meeting to review your request. They have agreed to schedule a special meeting for July 30, 1992 if you wish to continue with your Reasonable Use Exception. RESPONSE TO JUNE 29, 1992 LETTER: This section specifically addresses the statements included in your recent June 29th letter. The response is presented below in the order that follows your letter's contents. Paragraph 1 alleges the City waited 6 months to inform you that you would need a wetland Page 4 study on the Hillcrest site. However, your wetland consultant - A.J. Bredberg & Assoc. conducted a wetland site visit during August of 1991. This wetland documentation was dated 1/8/92 and submitted to the City on 1/13/92. It included a map but was not conducted or reported as a wetland delineation study. The SAO was adopted on June 10, 1991 and clearly states that sensitive area studies are required unless a waiver is granted by the DCD Director. Therefore, the City informed you of on -site wetlands prior to your formal BLA application submittal on 9/6/91. Paragraph 2 Staff could not determine what the standards would be for application requirements until the SAO was approved on June 10, 1991. Based upon the adopted Sensitive Areas Ordinance, you submitted your application on September 6, 1991. Paragraph 3 states that your engineers recommended that the Hillcrest site must be dewatered to stop further deterioration of Slade Way and the downslope property. Dennis Joule, P.E. provided you with a letter (1/15/92) that included a discussion of dewatering to improve slope stability. This letter did not represent a site - specific study or refute the site - specific findings of the Cascade Geotechnical reports of 5/30/90, 8/27/90 and 4/24/91). In addition, there were no clear recommendations indicating the site must be dewatered. The letter written by Richard Stuth, P.E. (2/17/92) recommends "controlled responsible development..." and "... dewatering and stability measures that would assure stability over the entire affected area." This statement does not imply that the entire site must be dewatered as a prerequisite for some type of development. Paragraph 7 indicates your wetland consultant's report (4/16/92) was submitted to the City on 4/20/92. The Urban Environmentalist assisted by meeting with A.J. Bredberg to help with needed revisions for the wetland boundary. As you are aware, some wetland areas were missed during the wetland initial study. As a result, a revised wetland report was submitted on 5/15/92. The wetland study was verified and approved by city staff. However, the study does not address your position of eliminating wetlands on the site. The SAO clearly states the requirement for assessing impacts and producing a mitigation plan to replace wetland area and function. We informed you of the mitigation requirement at both the 6/3/92 and 6/24/92 meetings.: The wetland mitigation requirement was also included in Darren Wilson's (City Planner) 1/30/92 letter, addressed to you, that summarized a meeting we had on 1/21/92. Several options, discussed in this letter, were presented to you during our 6/24/92 meeting. None of these options denied your reasonable use petition. As previously stated, the City recommends that peer review of the geology and hydrology data and features of the site be conducted prior to a reasonable use hearing before the Tukwila Planning Commission. Otherwise, you may experience additional delay if the Commission agrees with staff that the peer review is necessary prior to deciding the reasonable use issue. As you know, this is a very difficult site due to the slopes, wetlands and public facilities Page 5 issues. The City staff has tried to assist you within the limits set in the SAO. Your proposal to eliminate the wetlands without proposing any wetland mitigation conflicts with the intent and requirements of the ordinance. This severely limits staff's ability to assist you in navigating the permit processes as quickly as possible. If you should have any questions or desire some clarification in this letter, please feel free to call (431 -3686) or write. S' erel Jac ' ace cc: Phil Fraser Senior Planner Gary Schulz ..._. LEROY C. LOWE A.I.A. ARCHITECT P.O. BOX 1241 SEATTLE. WASHINGTON 98111 JACK PACE PLANNER CITY OF TUKWILA HILLCREST B.L.A. DEAR MR . PACE i 0 2 1992. • ,,i; i IP JUNE 29 , 1992 THE CITY WAITED 6 MONTHS TO INFORM ME THAT YOU WOULD REQUIRE A WETLANDS STUDY; TO HOLD ME HOSTAGE FOR HALF A YEAR WITH NOT ONE SINGLE COMMENT OR WRITTEN COMMUNICATION ONLY TO DEMAND MORE INFORMATION IS UNCONSCIONABLE AND FLAGRANTLY UNPROFESSIONAL. THIS PROJECT HAS BEEN BEFORE YOU AND THE CITY STAFF FOR OVER 2 YEARS. THE CITY COUNCIL AND MAYOR VOTED UNANIMOUSLY TO LIFT THE S.A.O. MORATORIUM ON THIS PROJECT ON JULY 2, 1990. I THEN PROCEEDED TO PRESENT THE HILLCREST B.L.A. TO YOU AND THE TUKWILA CITY STAFF IN AUG OF 1990. A FORMAL APPLICATION WAS PRESENTED TO THE TUKWILA STAFF ON SEPT. 6, 1991 THE EARLIEST DATE POSSIBLE BECAUSE OF THE S.A.O. MORATORIUM EXTENSIONS. • • PAGE TWO --SIN LEROY C .' LOWE A:�I CC : RICK BEELER AT THE PLANNING COMMISSION PUBLIC HEARING MAR. 26, 1992 ON MY APPEAL TO YOUR DEMAND FOR A WETLAND STUDY; YOU PLEADED WITH THE PLANNING COMMISSION TO REQUIRE ME TO PROVIDE THE PLANNING COMMISSION WITH A WETLAND STUDY BECAUSE MY ENGINEERS HAD RECOMMENDED THE SITE MUST BE DEWATERED TO STOP FURTHER DETERIORATION OF SLADE WAY AND THE DOWN SLOPE PROPERTY AND YOU, MR. PACE, WANTED AN INVENTORY OF WHAT WAS THERE . MY POSSITION WAS THAT IT WAS FOLLY TO SPEND MONEY STUDYING A WETLAND THAT WAS SOON TO DISAPPEAR•BY RECOMMENDATION, IN ORDER TO PROTECT THE PUBLIC HEALTH, SAFETY, AND WELFARE. THIS WETLAND STUDY WAS COMPLETED AND SUBMITTED TO THE TUKWILA PLANNING STAFF ON APRIL 20, 1992 IN RESPONSE TO THE PLANNING COMMISSIONS REQUEST FOR SAME . YOU ASKED FOR A MEETING WITH ME FOR JUNE 24, 1992 IN RESPONSE TO MY PETITION FOR A REASONABLE USE EXCEPTION AS PROVIDED FOR IN YOUR S.A.O. ORDINANCE AND A SUBMITTAL OF THE WETLAND STUDY TO THE PLANNING COMMISSION AS THEY HAD SO REQUESTED. MR. PACE YOU HAVE HAD OVER 2 MONTHS TO REVIEW THE WETLAND STUDY ANDS MONTHS TO REVIEW MY B.L.A. APP. AT THAT JUNE 24 MEETING YOU STATED THAT YOU WOULD NOT SUBMIT MY REASONABLE USE PETITION WITH THE WETLAND STUDY TO THE PLANNING COMMISSION . MR . PACE YOU ARE DENYING ME MY CONSTITUTIONAL RIGHT TO PETITION MY GOVERNMENT; I THEREFORE HIGHLY RECOMMEND THAT YOU SUBMIT MY PETITION IMMEDIATELY. MEMORANDUM TO: PHIL FRASER SENIOR ENGINEER DATE: APRIL 5 1991 PROJECT: HILLCREST SUBJECT: UTILITIES DEAR MR. FRASER: ENCLOSED ARE LETTERS OF UTILITY AVAILABILITY FROM : VERY TRULY YOURS LEROY C . LOWE A.1 .A ARCHITECT VAL VUE SEWER DIST. WATER DISTRICT #75 WATER FLOW CHART LEROY C. LOWE A.L.A. ARCHITECT .O •O• 1••■ •U ^.rt.C, Wa.•11MOvo . *O111 This c' 'lticate provides the Depart,,,,. nt of Health and Building s Land Development with information necessary to evaluate development proposals. Please return to: BUILDING & LAND DEVELOPMENT 450 Adrnwnnaatwn Budding Seattle. W.Mm,tat 11104 201 344 7100 KING COUNTY CERTIFICATE OF SEWER AVAILABILITY To met/fief/ in clue box number name ❑ Building Permit ❑ Short Subdivision APPL SCANT' S NAME ❑ Preliminary Plat or P(JD ❑ Bosons or other PROPOSED USE Ri S t, 0 s is T14L_ LOCATION /6211 4 SLAD (#JAY (Attach map & legal description if necessary) SANER AGENCY INFORMATION Sewer service an existing and the sewer • 0,3 r I I • I w O p be provided by side sewer connection only to e wise sewer 004 feet from the site system has the capacity to serve the proposed use. OR b.12 Sewer service will require an improvement to the sewer system oft ❑ (1) and /or ❑ (2) the construction of a collection system on the site: and /or ❑ (3) other (describe) feat of sewer trunk or latteral to reach the site; 2. (Must be completed it 1.b above Is checked) a. OR b. 0 3. a. OR b.12 Annexation or BBB approval will 4. Service in subject to the following: a. Connection charge: b. Easement(s): c. Other: The ystem improvement is in conformance with a County approved sewer comprehensive plan. The sewer system improvement will require a sewer comprehensive plan amendment. The proposed project is within the corporate limits of the district, or has been granted Boundary Review Board approval for extension of service outside the district or city. be necessary to provide service. I hereby certify that the above sewer agency information is true. This certification shall be valid for one year from date of signature. .. !; DI f1.1CT Agency Name F27, Title T. J R'I11T1 7..I: :Ii signatory Maae /0/S//- 9/ .. Date • P 0 BOX 68063 SEAr7LE WA 98168 HILL CQ$T LOCAL DISCA1PT10N That portion of the Northwest 1 of the Northwest 1 of Section 26, Township 23 berth, Renee 4 Bast, W.N., In Ring County, Washington, described se follows, Commencing st the West 1 f said section, thence along the Westerly line of meld section, North 1.14,13' Neat 1600 feet; thence S outh 11•21'7*' Sect 664 feet, thence North 1.14'13" West 140 feet, to the Tres Point of MginningI thence North 81'21'11' West 334 feet, thence North 0.14'13' West 354.12 fest, thence Noeth 81.21'31' Net 140 feet, thence North 0'14'13' West 153.00 rest to the southwesterly line of South 140th street louthweet, thence along sold Southwesterly Line, South 704S'05' Seat 142.41 feet; thence South 76.07'40' east 61.43 feet to • pint which bears North 0.14'13' West from the Tree Point of Sslinning, thence South 8.14'12' Bast 440.18 feet to the Tree Point of neglnning, IAC5O KNOW AS portions of Lots 37, 21 end 21, •lock 2, Ncnicken Might., Division Number 1, according to the unrecorded plat thereof,' TOGETNER WITH that portion of vacated South 160th Street adjoining which attached by operation of 1•w; ERUPT that potion thereof conveyed to the City of Tukwila for Slade Way, by deed recorded under Recording Number 53441611 AND tECEPT that portion thereof condemned in United States District Court, Western District of Washington, Northern 06.6.10.. Civil Case Number 40101 AND UC•PT that portion thereof described es follows, Commencing et the West 1 corner of sold Section 361 Thence North 1.14'13' West along the West line of said eviction 2004.112 feet, thence south 11'21'71' East 330.00 fest to the True Point or Beginning' thence South S 8'21'31' Bast 140 feet, thence North 0'14'13' pot 153.01 feet to the South line of South 160th Street, thence North 70.55'0S" West along said South line 141.34 test to • point which is North 0'14'13' West from the True Point of beginning, thence South 6'14'13' Bast 200 feet to the True Point of beginning; AND EECRPT that portion thereof described as follow., Commencing et the West 1 corner of sold Section 24; thence North 1.14'13' West along the West section line 1740 feet, thence South 11'21'31' pet 520 feet, thence North 0'14'13' West 301.24 feet to the True Point of Reglnning, thane continuing North 0.14'13' West 190 feet to the South- erly msrgln of South 160th 1068. 8, thence South 70.15'05' east along said margin 61.43 feet, 111.001 South 76.07'40' East 71.34 feet to the int.resetlon of said margin with the Westerly margin of sleds Way; thence S outh 13'31'57' West along said Westerly esrgln 141.21 feet; thence North 11'41'47' West 118.11 feet to the Troop Point of beglnnlne. LEROY. C. LOWE A.I.A. ARCHITECT /fa E5oI4 •3972 eer . 5-vv6 w4 648007 Rkwc-: .164- 4423 �� •• M .•w.•••• . I • .■..n. ••w....•. .•.• .+ 11- .r•Val . w rte. ••O .a.1. • a .• r. ..t.1 YI u•u w Ic -4 7 AS BUILT r IFtf r r •i e l " rn rhiunhoe 240 '9. PINIISS L'MI,T• •'*' ��' TUKWILA L.I.D. 26 �� • rwF•.•••w•.•�wwll.•.ul..1f11•.• M = c- ons-_u_Itnt� 4 rj, ��~ r YOSHIDA INC. n • 14100 1j0 c..1.111.1•1.f1 ,.1f Atll ywA /NINOtO r1 SANITARY SEWER SYSTEM — • M ...we C�x� .w.w y 1.��., Ia50 705a EASEMENT This Indenture made this day of r' di, 1974, between PUGET WESTERN, INC., a Washington corporation, ereln called "Granto ' an the VAL -VUE SEWER DISTRICT, King County, Washington, a municipal corporation, herein called "Grantee "; WITNESSETH: That in consideration of the sum of Ten Dollars ($10.00) in hand paid, receipt of which is hereby acknowledged, and the performance by Grantee of the covenants hereinafter set forth, Grantor hereby grants to Grantee, without warranty of any kind, a right of way not exceeding 10 feet in width for the construction, maintenance, replacement and operation of the following described facility: A sanitary sewer line not exceeding 8 inches inside diameter, within and across the following described land situated in the County of King, State of Washington, to -wit: The south 10 feet of: * Lot 27 Block 2 McMicken Heights Division 11, unrecorded; less portion northerly of line beginning 301.24 feet north from the southwest comer; thence east to the east line; less street; ALSO, the south 10 feet of the east 135 feet of: * Lots 28 -29 Block 2 McMicken Heights Division #1, unrecorded; less beginning at northwest corner of Lot 29; thence south 200 feet; thence east 140 feet; thence north to the northerly line of Lot 28; thence northwesterly to beginning; less the east 70 feet; Except south 301.24 feet of Lot 28; * ALSO, the west 10 feet south of Slade Way of: Lot 26 Block 2 McMicken Heights Division #1, unrecorded; less street. This easement is granted on the following terms and conditions: 1. Grantee agrees that said sewer main will be buried at least five (5) feet beneath the natural surface of the ground at all points. 2. Grantee agrees to notify Grantor 48 hours prior to beginning of construction by calling 454 -6363, extension 630, Bellevue, Washington. 3. Said easement shall include the right of ingress and egress to, upon and over and across said land to construct, maintain, operate, repair and replace said sewer line and all connections and appurtenances thereto, and also grants to Grantee the use of such additional area immediately adjacent to the above easement as may be necessary for the construction of said sewer, such additional area to be held to a minimum necessary for that purpose. The grant for use of additional area shall terminate upon completion and testing of said construction, or no later than December 31, 1974. 4. Grantee agrees to save and hold Grantor harmless from all loss or damage which may be due to the exercise by Grantee of the right herein granted, and from all claims for such damage by whomsoever made, and to indemnify Grantor for all such loss, damage or claims. 5. Grantor shall not be liable for any loss or damages to Grantee's facilities resulting from Grantor's use of the lands encumbered by this easement unless such loss or damage is due to negligent act or omission of Grantor. Grantor agrees to use reasonable care. 6. Grantor reserves the right to develop easement for any purpose not inconsistent with reserves the right to construct buildings over of Grantee, which consent Grantee agrees shall due regard t: Grantee's facilities. • and use the lands encumbered by this the rights granted herein. Grantor said easement upon securing the consent not be unreasonably withheld, having * SAID LOTS BEING A PORTION OF THE FOLLOWING DESCRIBED PROPERTY. (SEE ATTACHED DESCRIPTION). • • This certificate p} •Ides the Department of Heal` And Building Ni Land Development with information necessary to evaluate development proposals. Please r_cn to: BUILDING & LAND DEVELOPMENT • Parks, Planning i Resources Dept. 3600 - 136th PLACE Southeast Bellevue, *Wallington 98006 -1400 (206) 296 -6600 KING COUNTY CERTIFICATE OF WATER AVAILABILITY zt• in Mrs box number name ❑ Building Permit ❑ Short Subdivision ❑ Preliminary Plat or PUD ❑ Rezone or other APPLICANT'S NAME,/ Litny 'c. Lo..'E 14SY PROPOSED USE/ s,vdCCE r.do.KIcr C s- L •T Sfi.LT LOCAT ION/ 5. /to '?' $ ,—. .— s �• w'.. s . MAY 1 C 1090 J (Attach sup i legal description if necessary) 1 1 1 1 1 1 1 0 0 1 1. 0 • MATER PURVEYOR INFORMATION 1. a. ater will be provided by service connection only to an existing water main ZJ feet from the site. 1 1 1 4 .. size OR b. ErWater service will require an improvement to the water system of: 1.J [}(1) s-300 feet of water main to reach the site; and /or 911) the construction of a distribution system on the site, and/or ❑ (3) other (describe) 2. e. 0 The water system is in conformance with a County approved water comprehensive plan. OR b. he water system improvement will require a water comprehensive plan amendment. 3. a. n,The proposed project is within the corporate limits of the district, or has been �`� granted Boundary Review Board approval for extension of service outside the district or city, or is within the County approved service area of a private water purveyor. OR b. Annexation or BBB approval will be necessary to provide service. 4. a. � water ie,ea will be available at the rate of flow and duration indicated below at no less than 20 psi measured at the nearest fire hydrant ..3o v feet from the building /Asepss4 (or as marked on the attached map): Rate of Flow Duration ❑ less than 500 gpm (approx. ❑ 590 to 999 gpm 01000 gpm or :me ❑ flow teat of gpm ❑ calculation of* gpm OR b. Crater system is not capable of gpm) ()less than 1 hour ❑ 1 hour to 2 hours FOR 9-2—hours or more ❑ other (Commercial Building Permits require flow test or calculation) providing fire flow. COMENTS /CONDITIONS a•A4 i'7L.& JYSTL.•c IN.osi &C L'.Pt T -.NIyA/T.o.A/ A ✓LLoCI7r •% :• 7 A/i o$- I hereby certify that the above water purvt ;yor information is true. This certification shall be valid for one year from date of signature. KING CWN Y WATER DISTRICT 0 75 Agency Name. Supervisor of Engineering i Adniniatratioo F 270 Title any E. Gibson Signatory Name rAeife v gnaturo Date Co 1:41.4 • I "4 j r • • 4e.i. • -:- • • -;--oa ' 4 tgrj: lik74 itt; *tf‘ :4 ORIGINAL DESIGN CONCEPT 3 .....=ssveze x'Atlx- 03e.am lC ST252alr.'2'4[ B,EIVIMMIM 57dti -5,..1 1==Q/u==nrPIfILoiPb`J:tiR:PMOZZacm. +il t.~5IDag. LEROY C. LOWE A.I.A. ARCHITECT P.O. BOX 1241 SEATTLE. WASHINGTON 98111 TUKWILA PLANNING COMMISSION TUKWILA WA. HILLCREST B.L.A. REASONABLE USE EXCEPTION DEAR MR . BEELER JUNE 15, 1992 ON MAR . 26 , 1992 THE TUKWILA PLANNING COMMISSION SPECIFIED THAT A WETLAND DELINEATION STUDY BE PROVIDED IN SUPPORT OF THE HILLCREST BOUNDARY LINE ADJUSTMENT APPLICATION . THIS STUDY WAS COMPLETED AND SUBMITTED TO THE TUKWILA PLANNING STAFF ON APRIL 20, 1992. WE ARE BEING DENIED REASONABLE USE OF THIS PROPERTY BY APPLICATION OF THE SENSITIVE AREA ORDINANCE. WE THEREFORE REQUEST A REASONABLE USE EXCEPTION BE GRANTED UNDER ART. 18.45.115 S.A.O. ITEM (A) WEST PORTION OF PROPERTY UNBUILDABLE FOR REQUIRED ROAD TO SAME WILL NOT MEET FIRE MARSHALL'S STANDARDS; I .E . 15% MAX . ROADWAY SLOPE IS NOT POSSIBLE . ITEM (B) LOT #6 UNMARKETABLE BECAUSE OF SIZE, SHAPE, AND TOPOGRAPHY. (SEE ATTACHED REALTY LETTER.) ITEM (C) TO PRESERVE AND PROTECT THE WETLANDS WOULD UNREASONABLY THREATEN THE PUBLIC HEALTH , SAFETY , AND WELFARE. THIS WETLAND PUMPS WATER INTO THE DOWN SLOPE AQUIFER DESTABILIZING SLADE WAY AND THE DOWN SLOPE PROPERTY. (SEE REPORTS FURNISHED TO PLANNING COMM. MAR. 26, 1992) . THIS INFORMATION IS SUBMITTED IN SUPPORT OF OUR REQUEST FOR A REASONABLE USE EXCEPTION. WERE WE TO FOLLOW THE WETLANDS ORDINANCE, WE WOULD BE DENIED EVEN REASONABLE USE OF OUR PROPERTY . OUR PROPERTY IS ZONED FOR 12 LOTS, WE REQUEST 5 LOTS. SINCERELY YOURS, LEROY C . LOWA.I.A. A TEC T O 1 O Gf n NN 0. • in Q. O N W U1 W W • z O Q co Ir W W as 33 >> B.L.A. APPLICATION FILED 9 -6 -91 1990 1991 1992 N c N to O N 1 M O O Na z E • W W J 0 N D 0 Z z Q z H Q W a 3 REASONABLE EXCEPTION REQUESTED 6 -15 -92 HILL CQEcT BOUNDARY LINE ADJUSTMENT CHRONOLOGY LEROY C. LOWE A.I.A. ARCHITECT RS. sum II I M■1Rt. W.NII.. IOM 55111 1993 1994 I ' I I I 1 . I. 1 1 I I I � I I I {I I I I I I- 1 1' 1 1 1 1 {1 J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D n.4RMflr..R U.1Vi?' MA June 10, 1992 LeRoy C. Lowe, A.I.A. Architect P.O.Box 3972 Bellevue, WA 98009 Dear Mr. Lowe, You have asked me to assist in marketing your Hillcrest project in Tukwila. I have done so, and have been involved since May of 1990. More recently, you have asked for my opinion regarding the marketing if lot 16 of the Hillcrest project. My opinion is as follows: Lot 16, because of it's restrictive size, shape and topography, is not a desirable property and would be most difficult, if not impossible, to sell as a building site. My recommendation would be to put this lot on hold indefinitely. The balance of the property could be brought to the market place at a break even, or slightly better price. Please let me know if I can be of any further assistance. Sincerel Richard H. Osborne President 653 228th Avenue N.E., Redmond, Washington 98053 Phone (206) 868 -7100 or (206) 392 -1678, FAX. (206) 868 -1750 „ • • •••.- • - N vv «v•c 'Y 41 \G COUNTY AS 9,WIGA 0KU 30,5 c.c.'. C.7 C� ruKw• 4iA oR0 3 14 C] 1331,94 ,) 0 • r a d ivy T M Rj n0 4h o 0�y\ D. 160' coos A/89-3/- /31V 225.0 2.05 o co WNW 2/ 3IW •U m o 00 0 i2 0 ?$4.85. N N69-Z / -.3/W t461.1.8s ,y70•SS•O5 4' .G.oS TUK SP 79 -43 —SS AF 8002260429 /33.35 loo Q 3I 0006 5. 163RD. PL. .5. d9• Z/. .3/447 ..5"-c..4. s 00 ' Ilo !o, /2G.( Ps 58'8-03• s•oaf.' /. 49.38 /0 r99. a/..> /G;' i34 0 0° 0 s. 1h00 0 o. 150. l 14.0 A-57. go 2 31-W. Li 03 •1,104 R:,: a 90. / APR 2 G 1992 CI'FY OF t urmILA PLANNING DEPT. WETLANDS STUDY CITY OF TUKWILA HILLCREST LEROY C. LOWE, A.LA. ARCHITECT 410 BELLEVUE WAY S.E. BELLEVUE, WASHINGTON 98004 454 -4423 SITE LOCATION: SLADE WAY AND SOUTH 160TH STREET TUKWILA, WASHINGTON PREPARED BY: BREDBERG AND ASSOCIATES, INC. POST OFFICE BOX 1337 GIG HARBOR, WASHINGTON 98335 (206)858 -7055 JOB # 1112 APRIL 16,1992 TABLE OF CONTENTS PAGE INTRODUCTION 1 SITE DESCRIPTION 1 METHODOLOGY 4 WETLAND A VEGETATIO N 5 SOILS 5 HYDROLOGY 6 WILDLIFE 6 VALUES & FUNCTIONS 7 WETLAND B VEGETATION 10 SOILS 10 HYDROLOGY 11 WILDLIFE 11 VALUES & FUNCTIONS 11 WETLAND C VEGETATION 10 SOILS 10 HYDROLOGY 11 WILDLIFE 11 VALUES & FUNCTIONS 11 UPLANDS 12 IMPACTS 15 RECOMMENDATIONS 16 TABLE OF CONTENTS, CON'T. FIGURE 1: VICINITY MAP FIGURE 2: WETLAND LOCATION & TOPOGRAPHY MAP FIGURE 3: WETLAND AREAS FIGURE 4: CITY OF TUKWILA,WETLAND MAP FIGURE 5: KING COUNTY SOIL SURVEY APPENDIX A: TUKWILA WETLAND RATING FORMS APPENDIX B: TUKWILA WETLAND DATA FORMS TABLE 1: VEGETATION LIST LEROY C. LOWE ARCHITECT IIILLOZ671 .=0/z.e• -14,40vo _ I _____750/WG7M/C aim NC) •.5GAZZ 0 N • — .C2 /5- o , , I ‘ii ..)c /Z "Gt. „ 1, x /2 4.. 7-zas - -1— / G NA \ .....141:7°P 7ZZASS e / 4 p 1, ..) 4 Gea V.1...• L. 7Z.L.. ) ) (•'J G4AZ4 Z &' ■ ■ LEROY C. LOWE A.I.A. ARCHITECT 1 4 .1 N 4) o: 1 e woodo .4:74..z.5 /06 0/4 /I /A/ . c=)" /A/ A1477 +./E .50/4. 5 Ai4e. za4 47, re,C, Les5 "AC 71i.e1 p, 74/c. Z.Z5 5 d3i/X /2" CO/VC. -/c4 "CR G,e,cp.oe Apeced/s/wr, c.-4,ZAGZ FOCIA4004710A1 fiA74A // 1/4 / PLArN HILLCIZST n.IM$ REGIST ARCHITECT ERED LEROY C. LOwE STATE OF WASHINGTON 24 V•i000 _WW �1}NI Or�I yt11 N-S TO'' 1.173 ..2 - ` 0.c. _a,7 �xvc7ot� - FIZZ . DRAIN Wf114 LIMI.rnet miss.asTra TL 1614 VCIISITIIERgi LEROY C. LOWE STATE OF WASHINGTON /// ; - Et.41-..,V15aL011511•4 \mE-4=nEt- -"1•■••).0:2--71111,-..---11■3- X4IVlElti1C4Krfl--L 1.1buzz.5_73..azttr. 1=PlP1 44■S__SielOo.N61_1S .11.__KZEAR..-3 -28-35E 1 c.c. w/ Pi7iC c 12.:=13:1=77161 riL=S-&-K41:57c--- PLAN4 11.1611 %TUC LEROY C. LOWE STATE Of WASHINGTON . V V 4.00 1G J r o o,ki . LOUNiY ASSESSOR ��- 1lYM Iry S* 23.23• • +..J v.. r0: ail =rs 1 1..•119.- •1' 11•01 l alma • 1 r• • r . ••• • l 1W 00 a..A.11/ M /N.IN■o11 . •I_- , • t • Kl I r 1 6 2 PC, as .1. .•'.'i•1 .r. .... • ... .. • 1. .sf• 13 S 11131110. •L. —711s. TrICTAIT Ale a ..I iA.. r f • f ... W......4.9........44. _ ;. r 1 e r t 1 a 1 • ..emu ▪ - ....�•r-.-. • .=.—.: _ _�, 1' : rr I.. 9 r• ,r 'L ..a' It I �,/ l... r! O Ot . .•••- 5'..... •.. AO 170.147.-1 .... • 1• 1 •2. • ` e I. • • • • 1 •D .! + • 1' _ 10 • LIT L TU.SPSI- 20•SS- e107020714 • • ...1. )r or '.l •5 50 + > i .. • ....•. .•.■ •. .a• 1,•`7 -- if —�.: 66tH j . M M .05 • 11 1 �Ir i • 1• Hydrant No. Flow gpm :4A f ER ►- i_.OW I E ST SUMMARY SHEET Residual psi Date: 1— 23- 91 Time: ILO; QD M Cont. No. n 0 Scale A Scale 8 Scale C 120, 115 110 105 100 95 90 85= 80 75 70 65 Static Press: 1 0 1Iiiii!11191 P.s 54G 60 55 50 45 40 35 30 25 20 1 10 iircamm rtim Scale: 100 200 300 200 400 600 400 800 1200 400 800 1600 1000 2000 600 1200 2400 700 1400 2800 Water Flow gpm ISSO° Eno0 3200 900 1800 3600 ma Viking Hastings, Litho in U.S.A. 1000 2000 Cmpo.ation 4000 Michigan form No. 3016 S rw I P 2 N OF 9LKrP 1 900 -J-1501 �s t x';` 16C) L z1041 t o'11•v(oyl 1;C iii1501413 viiitG +i r' ,_\T .CFFO':E.'f(: 77 '.G ? ANY ,'��.r" .. 7 Fr' Ft k F.C.'L.•Ti_. 73 "• .:` .... ... T -it: iti.l.`.', L�Ctri[�i1 • 2-it-5. COMPANY, :«,roveman; Sectic:1 t\i‘‘), 3'N we 2ft E as- td�oCN ip iT xK 3,;i OI ESM'T) •3'Nafe. �.9 ..E 0 r A + n.^. A71UN • ';qtr,:. .. ,•.;':G WASNiNGTON NA • ` • Public AUG 3 01311 Dal e: N -O Th€lZ C.4-1,c._ 2 - - Zit "7 M tTe- tt�t.c_ a `5: 040.4 Y� �1. 0011.11.141441. 011 .4 /4, 144... 1.467.111. 411. 1000 1167. awn 11113111• I1M 141...0.4 611 • 1t 4.444 46/ .4.1.11 141404/4. MEM it 10' SCKR SASL14CHV • O- .•4 4rt•• 27 1 /1N. e1••..c rM LEGEND CS txbrt POST 0 commit • CATCH IMP 0 SS 1w4NO1i ( • 06Clowuf 4" CUCKRI • RCMR HT .1. WIN • KIM 101.0 5 IV yBy i ti r3 ta 'VS • ca or x14 O Gi W CC �sCs N ciL• tql44" Y • ..0 * * * * * * * * * *+1 * *** * * * *** ** k4. * ** * * * ** * * * *) # ** * * * * * * *** SCHMID ALFRED 1525 TAYLOR AVE N :101 SEATTLE WA 537920 - 0006 -02' LSCHMID ALFRED 1525 TAYLOR AVE N SEATTLE WA 537920 - 0006 -02 SCHMID ALFRED 1525 TAYLOR AVE N SEATTLE WA 537920 - 0060 -05 BILDEN WESLEY 16024 51ST S TUKWILA WA 537920- 0061 -04 - LAWRENCE THOMAS E 16010 51ST AVE S SEATTLE WA 537920 - 0062-03 AVERY W L 16014 51ST AVE S SEATTLE WA 537920 - 0062 -03 AVERY W L 16014 51ST AVE 5 SEATTLE WA 537920- 0065 -00 SNOW DAVID M 16030 51ST AVE SOUTH TUKWILA WA C0480 98109 C0480 98109 98109 98109 443606 98188 98188 0775 98188 0775 98188 849999 98188 537920 - 0070 -03 ERICKSON ELDON O +JULIE C 889999 537920- 0005 -03 SCHMID ALFRED 1525 TAYLOR AVE N ti101 SEATTLE WA 537920- 0005 -03 SCHMID ALFRED 1525 TAYLOR AVE N :101 SEATTLE WA 537920-0006 -02 SCHMID ALFRED 1525 TAYLOR AVE N SEATTLE WA 537920- 0006 -02 SCHMID ALFRED 1525 TAYLOR AVE N SEATTLE WA 537920- 0060 -05 BILDEN WESLEY 16024 51ST S TUKWILA WA 537920 - 0061-04 LAWRENCE THOMAS E 16010 51ST AVE S SEATTLE WA 537920 - 0062 -03 AVERY W L 16014 51ST AVE S SEATTLE WA 537920 - 0062 -03 AVERY W L 16014 51ST AVE S SEATTLE WA 537920- 0065 -00 SNOW DAVID M 16030 51ST AVE SOUTH TUKWILA WA C0480 98109 C0480 98109 98109 98109 443606 98188 98188 0775 98188 0775 98188 849999 98188 537920 - 0070 -03 ERICKSON ELDON D+JULIE C 889999 tLntn g1CT AU= C 16202 51ST S SEATTLE WA 137920- 0076 -07 THAIKLAR CHRISTOPHER K+ LAKSANA Y _ 16210 51ST AVE SO TUKWILA WA L37920 - 0080-01 IVERSON 0 EUGENE 4441 S 188TH SEATTLE WA I37920 - 0081 -00 KAUFMAN LINDA M 10040 37TH SW SEATTLE WA' L.. 0,81840- 0010 -09 MCLESTER R 5118 S 164TH ST SEATTLE WA i 681840- 0020 -07 SARGENT MARGARET G PO 80X 924 SEAHURST WA L81640-0030-05 HAGEN MARVIN L 5134 S 164TH ST SEATTLE WA 81840- 0040 -03 HERBEL JAMES D 16243 52ND AVE S TUKWILA WA �81840- 0050 -00 , SCHWARZMANN JOHN E 16251 52ND AVE S C0781 98188 059999 98188 98188 702284 98146 0175 98188 859999 98062 98188 119999 98188 C0579 537920-0071-5'. SOWINSKI HEiiN C +ST V /T /0 009999 16050 51ST AVE SO TUKWILA WA 98188 537920-0072 -01 KNIGHT ALICE 0 16044 51ST AVE S SEATTLE WA 537920- 0075 -08 LAFOND RAYMOND 16202 51ST S SEATTLE WA 537920-0076-07 THAIKLAR CHRISTOPHER K+ LAKSANA Y 16210 51ST AVE SO TUKWILA WA 537920-0080 -01 IVERSON 0 EUGENE 4441 S 188TH SEATTLE WA 537920 - 0081 -00 KAUFMAN LINDA M 10040 37TH SW SEATTLE WA 681840- 0010 -09 MCLESTER R 5118 S 164TH ST SEATTLE WA 681840- 0020 -07 SARGENT MARGARET G PO BOX 924 SEAHURST WA 681840 - 0030 -05 HAGEN MARVIN L 5134 S 164TH ST SEATTLE WA 681840- 0040 -03 ' HERBEL JAMES 0 16243 52N0 AVE S TUKWILA WA 681840.0050 -00 SCHWARZMANN JOHN E 16251 52ND AVE S 98188 C0781 98188 059999 98188 98188 702284 98146 0175 98188 859999 98062 98188 119999 48188 C0579 870050- 0010 -03 ONORATI ERNEST C 5102 S 163RD PL 681840-00607-1 REARICK Irs WILLIAM D +L0RRA079999 16244 52N0 AVE S TUKWILA WA 98188 681840 - 0070 -06 PHELAN HERBERT W 16250 52ND AVE S SEATTLE WA 98188 779640- 0010 -03 STEWARD RONNIE L +BRENDA A 889999 16351 53RD PL SOUTH TUKWILA WA 98188 779640- 0020 -01 LEE SEUNG +SU JA 16371 53RD PL S SEATTLE WA 779640- 0030 -09 BRYANT KEITH J +CHRISTY A 16405 53RD PL S TUKWILA WA 779640- 0040-07 SISSON DIANE R 16415 53RD PL S SEATTLE WA 910035 98188 980824 98188 969999 98188 779640- 0200 -03 KRAKOWSKI ROBERT & 032633 ST CLAIR SUSAN 16406 53RD PL S SEATTLE WA 98188 779640- 0200 -03 KRAKOWSKI ROBERT & 032633 ST CLAIR SUSAN 16406 53RD PL S SEATTLE WA 98188 779640- 0210-01 KENT RONALD R E TAMARA I 002726 16372 53R0 PL S TUKWILA WA 98188 779640- 0220 -09' SACCO ROBERT G +DIANA L 16350 53RD PL S TUKWILA WA 870050•0010 -03 ONORATI ERNEST C 5102 S 163R0 PL 999999 98188 - HOLL CARL E F I nl c 16ARO PL C094 98188 98188 C0480 98188 3N0757 98188 0577 98188 C0777 98188 C0779 98188 98188 0775 98188 870050 - 0030 -09 MUMMERT JAMES E +VIRGINIA R 609999 5106 SO 163R0 PLACE TUKWILA WA 98188 870050 - 0040 -07 NIELSEN RAYMOND 5108 5 163RD PL SEATTLE WA 870050 - 0050-04 JOHNSON CALVIN M 5110 S 163RD PL SEATTLE WA 870050- 0060 -02 GOE RICHARD A 5112 S 163RD PL SEATTLE WA 870050 - 0070-00 WELSH BARBARA E 5113 S 163RD PL SEATTLE WA 870050- 0080 -08 AMUNDSON ROBERT T 5111 S 163RD PL SEATTLE WA 870050 - 0090-06 YANKEE DAVID E 5109 S 163RD PL SEATTLE WA 870050- 0100-04 MYERS D R 5107 S 163RD PL SEATTLE WA 870050 - 0110 -02 CRAIN ROBERT 5105 S 163RD PL SEATTLE WA 870050- 0120 -00 HOLL CARL E 5103 5 163R0 PL C094 98188 98188 C0480 98188 3N0757 98188 0577 98188 C0777 98188 C0779 98188 98188 870050- 0120 -00 HOLL CARL E 5103 S 163RD PL SEATTLE WA 870050 - 0130 -08 CROWLEY WILLIAM J 5101 S 163RD PL SEATTLE WA 262304- 9138 -05 'PUGET WESTERN INC 19515 NORTH CREEK PKWY BOTHELL WA 98188 98188 ON0897 0310 98011 870050-0120 -00 HOLL CARL E 5103 S 163RD PL SEATTLE WA 870050- 0130 -08 CROWLEY WILLIAM J 5101 S 16340 PL SEATTLE WA 98188 98188 262304 - 9138 -05 PUGET WESTERN INC ON0897 19515 NORTH CREEK PKWY 0310 BOTHELL WA 98011 TUKWILA WETLAND REPORT HILLCREST The following report is prepared in an objective manner to describe the wetland and its values and functions. The wetland report follows the format as shown in the outline and discusses the values and functions according the wetland rating field form for the City of Tukwila (AppendixA). SITE DESCRIPTION The site consists of lots 25 through 29 on South 160th Street and Slade Way, tax lots #0226, #0230, #0224, #0220, and #0215. The site is located in the northwest quarter of Section 26, T23N, R4W. The property owner is Leroy C. Lowe, 410 Bellevue Way SE, Bellevue, Washington 98004. The subject parcel consists of 53,830.8 square feet in the subject parcel, and 10,176 square feet in a separate tract to the .south and east. The project consists of 5 separate tax parcels, with residences to the south of the parcel. The entire parcel is surrounded by either streets or single family residence lots. The parcel is bordered on the east by Slade Way and separated from Slade Way by a deep man -made ditch. There is a single family residence lot cut out of the northeast corner of the parcel, which is mowed and maintained with a fence around the perimeter. Additional homes are located to the northwest of the parcel and to the west across the level. Along the southern edge of the parcel is a 10 foot sewer easement. The topography is level to steeply sloping. The far western edge of the property is the highest elevation and is level uplands. Moving eastward, a steep slope drops down to the major portion of the site that includes the wetlands. The parcel slopes from the highest points at the western property boundary, east to Slade Way and northeast to 160th Street. The parcel shows evidence of considerable site disturbance. It appears that the site was used as a borrow pit at one time, as the site is terraced and the soil shows signs of excavation and re- grading. The dense tree and shrub growth indicate that excavation occurred several decades ago. Within the past few years there has been some grading and, most recently, clearing to facilitate placement of the test well. The site contains evidence of man's recent activities. Garbage cans and other assorted debris are present throughout the site. The ditch along Slade Way takes drainage from the lower portion of the site. Several footpaths are present throughout the site. A test well is located in the southern portion of the site. Two culverts are present on the woods road. Lawn and fruit tree encroach at the northeast corner of the property. A 40" Maple tree is just west of the lawn and fruit trees on a large mound of earth with signs of excavation around it. A culvert has also been placed at Wetland Flag #A to pipe the water to the roadside ditch. The northwest corner of the site also has evidence of landscaped encroachment. 2 The dominant feature of the site is the steep and relatively unstable bank of soil bisecting the property from north to south. The instability of the slope is evident as tree roots and bare soil have slid down the steep slope. It is this consultant's opinion that the site was a borrow pit to provide sand for construction at some time in the past. As the pit was abandoned, the steep slopes /vertical faces of the cuts lost their stability. The comments in this report on the slope stability are based on the surface layers of the soil and no inferences or recommendations as to slope stability with regard to geotechnical or foundations are made. SOILS: The following sections on wetlands and uplands give general descriptions of the soils within each. The site, especially in the area of the proposed development at the base of the slope, presents a complex soil situation. There are small areas of peat up to 3 -1/2 feet deep and within 25 feet there are sandy areas with no peat. The geotechnical soil logs describe a mixture of black to tan fine grained organic silty sand to depths of 5 feet. The description indicates that the site was likely a borrow pit. Deep organic deposits probably occur where the top soil and other organics have been placed and localized. The mixture of the silty sand and organics is likely to be where the bank has sloughed off and where machinery, as long as several decades ago, mixed the organics with the sandy material. At this time the definitive description of the soils can do little more than identify the site as a disturbed area with several seeps. The depth of the organic matter is not necessarily an indicator of the permanence or duration of the wetness. 3 METHODOLOGY The site was evaluated using the Federal Manual for Delineation of Jurisdictional Wetlands(1989). The routine methodology and data forms are provided in Appendix B. The Soil Survey, King County Area of Washington (1973), was utilized to make a general soil determination. A Registered Professional Soil Scientist prepared the section on soils. The wetlands were flagged and sequentially numbered and located by survey (Figure 2) Survey Professionals of 21436 SE 266nd Street, Maple Valley, Washington 98038, (206)251- 0189, performed a professional survey in locating the wetland flags. Additional information used in preparing the report include the geotechnical studies prepared by Cascade Geotechnical, Inc. of 12919 NE 126th Place, Kirkland, Washington 98034, (206)821 -5080. WETLANDS WETLAND A: Wetland A is the largest wetland on the parcel and covers 11,647 square feet. The wetland is vegetated by Scrub /Shrub vegetation with an overhang of trees growing in the uplands. Figure 2 shows the flag locations and the wetland configuration. 4 VEGETATION: Wetland A is dominated by emergent vegetation. Five Alder trees are growing in the vicinity of wetland Flags 1 through 3. The overstory of the trees growing in the wetlands is less than 25% for the entire wetland. Please note that the tree species as shown on the Wetland Survey Plan were located and identified by the surveyor. Some of the Red Alder trees are listed as Hemlocks. Table 1 lists the dominant vegetation present in Wetland A and in the uplands, respectively. The dominant vegetation in the wetland consists of a Scrub /Shrub layer of Salmonberry with an overstory of Himalayan Blackberry rooted in the uplands. Stinging Nettle and Skunk Cabbage are plentiful in the wetter areas, as are grass species and Water Parsley. SOILS: The soils of Wetland A are dominated by an organic layer over a B horizon of gray sand. The organic layer varies from 2 inches to up to 14 inches thick. The muck areas appear to be accumulations of top soil and organic matter that have eroded in the adjoining areas as the slope has broken off. Other areas of deep organics and mucks, appear to be a result of deposition by the placement of 5 rotting leaves or the movement of soil with equipment. The wetland soils are classified as a Norma series when the organic layer is less than 6 inches thick. The Norma series is a poorly drained soil on the hydric soils list. Where the organic layer is greater than 6 inches thick the soils are poorly drained and of the Dupont Muck series. HYDROLOGY: The hydrology of wetland A is dominated by the seeps coming from the hillside to the west. Four main seep areas are located in the vicinity of Flag #39, 44 and 56. The seeps support the hydrology as they have running water throughout much of the year. In the dry times of the summer the seep may stop running. The water seeps out of the hills to the west, flows through the site and into the roadside ditch along Slade Way. One culvert and several seeps transport the water from Wetland A into the roadside ditch. Two culverts are present on the site allowing the woods roads to access the site and the test well. WILDLIFE: The wetlands offer a diverse habitat for wildlife. Primary wildlife present on the site were songbirds. No sign of other mammals or large birds was noted. The trees in the uplands around the wetland offer nesting habitat, while the wetland themselves provide food and water source for the wildlife. The major function of 6 the wetlands are the seeps providing surface water for wildlife. The greatest factor affecting this wetland is the urban encroachment around the outside edge of the wetlands and the lack of a corridor for wildlife. For this reason these wetlands have a limited value for wildlife. VALUES AND FUNCTIONS: Food Chain Support: Wetland A is given a high rating for food chain support as 75 to 100% of the wetland is covered with emergent vegetation. Skunk Cabbage, Water Parsley, Stinging Nettle and grassy species support the food chain. Nutrient Transport: This wetland is given a moderate rating for nutrient transport as there is a seasonal stream leaving the wetland. The wetland is not given a high rating as the discharge from the wetland is collected in the roadside ditch and is transported into the storm sewer system at 160th Street and Slade Way. Buffer /Barrier Function: The wetland is given a low score for this function. Much of the area around the wetland has been disturbed and is either part of Slade Way, maintained lawn, or vegetated with invasive species such as Himalayan Blackberry. Much of the western portion of the wetlands buffer is part of the unstable slope that sloughs off, providing little protection for wildlife. Prime consideration in providing the 7 low score for the buffer function is the relative ease with which people have access to the wetland. Several paths enter the site. A road bisects the property that permits access to the test well and Slade Way has little buffer between the wetlands and Slade Way. Habitat: The wetland has 2 classes of wetlands without open water. The scrub shrub and emergent wetland class. Less than 20% of the wetland is forested, therefore, it is not given a forested class. The size of the wetland is 11,640 square feet, is less than 1 acre, therefore it is small and low in value. Forested Wetlands: The site is less than 30% forested wetland, therefore, is given a low value in this function. There is forest around the wetlands, but these consist of primarily of big leaf maple and alder trees growing in the uplands. �- As the wetland has less than 30% aerial coverage by trees, it is classified as a Scrub /Shrub wetland (Classification of Wetlands and Deep Water Habitats of the United States, 1979. Cowardin) �.. Habitat Buffer: The habitat buffer is diverse in that it encompasses a forested urban and scrub . Surrounding Land Use: Surrounding Land use is urban residential with maintained lawns. Unique Features: There are no unique features on this site other than the presence of the springs or seeps. The seeps would be given more value if the water was channeled into a stream. However, as the water is collected in the roadside ditch immediately upon leaving the wetland, and shortly thereafter tight line into the storm sewer system, there is little benefit from this as a unique feature. Presence of Water: Water flows from the seeps of the site much of the year, however, in the dry season there is the possibility that these wetlands dry up. Therefore this wetland is given a seasonal rating. WATER STORAGE FUNCTIONS: Location Water Shed: This wetland is located at the headwaters, or the springs or seeps of a watershed, therefore, is given the upper third score. Storage Functions: Little to no water is stored in the wetland. Size: The size of the wetland is less than 1 acre. 9 WATER QUALITY: Residence Time: The residence time of water in the wetland is short as it is a small wetland on a relatively steep slope for a wetland. A value of one is given for this score due to the small size and lack of residence time. Vegetation Density: Vegetation Density is approximately 70 to 100% coverage of the wetland with emergent vegetation, therefore, there is a high score for this value. Referring to Appendix A containing the data sheets for wetland A, the total score for the wetland is 20. WETLANDS B AND C: VEGETATION: The vegetation of wetlands B and C is similar and consists primarily of stinging nettle, skunk cabbage, and grass species. The wetlands are small and have an overhang of Salmon Berry and Himalayan Blackberry rooted in the uplands. SOILS: The soils of wetland B and C are similar in that they are on the unstable steep slope. The soils consist of a gray loamy sand to sand, with an organic surface 2 to 10 inches in thickness . The soils are classified as belonging to the Norma series, except where the organic 10 layer is deeper than 6 inches, in which case it would be classified as a Dupont Muck series. HYDROLOGY: Wetlands B and C are hydrologically isolated and can be classified as hillside seeps. Water seeps out of the hillside, and re- infiltrates making the wetlands isolated. WILDLIFE: Wetlands B and C offer little wildlife habitat due their small size and lack of surface water. VALUES AND FUNCTIONS: Values and functions of wetland B and C follow the analysis on the wetland rating field form for wetlands B and C in Appendix A. The two wetlands are located adjacent to each other and are similar in their wetland rating. Food Chain Support: The wetlands have a 50% cover of emergent vegetation are given a moderate score. Nutrient Transport: These wetlands are isolated closed depressions and receive a low score. Buffer: The buffer around these wetlands is not effective in reducing human encroachment. There are 11 3 footpaths adjacent to the wetlands, and garbage cans and other debris within the wetlands, showing that the buffer is no working. The test well is located between the two wetlands and it is possible that the drilling of the test well has created some of the wetlands. For this reason the level of human encroachment is very high, therefore, the buffer functions is low. Habitat: The wetlands have 2 wetland classes without open water,as emergent vegetation with some Salmon Berry are present. SIZE OF WETLAND: Wetland B is 518 square feet and wetland C is 1,011 square feet. Both wetlands receive a low score for wetland size. Percentage of Forested Wetland: Neither wetland is forested and is given a low score. Buffer Habitat: Between 10 and 25% of the habitat within 100 feet is a diverse forested shrub, while 25 to 50% is open forest with grass and 50 to 75% is pasture, herbaceous. The pasture, herbaceous is based on the close proximity of the grassed lawns to the wetland. Surrounding Land Use: The surrounding land use is urban residential and this provides a negative land value. Unique Features: There are no unique features in either wetland B or C. Presence of Water: There is the presence of water in these two wetlands is intermittent even during the wet times of the year. On this basis it is given a low rating. WATER STORAGE FUNCTIONS: Location of Water Shed: As these are isolated wetlands they are given an upper third or two score in the water storage function. Storage: The wetlands are small, less than 1 acre and are given a low value for this function. WATER QUALITY: Residence Time: The low flow into these wetlands and lack of any surface water provides for a low value for this function. Vegetation Density: These wetlands are given a moderate value for vegetation density as they are 50 to 75% emergent vegetation. The total score for the wetland rating field form for the City of Tukwila is 14 based on the totals of the three sheets. UPLANDS: The uplands of the property dominate the site and are present in three separate plant communities. The western upper levels of the parcel are a mixed forest of Big Leaf Maple and Red Alder, and an understory of Salmon Berry is present. Table 1 lists the dominant vegetation in the uplands. The second of the three upland vegetation communities consists of the steep slope breaking from the higher elevations to the lower elevations. The steep slope is vegetated with Red Alder and Big Leaf Maple trees and has an under story of Salmon Berry. The slope is breaking off and eroding down to the lower levels, with bare areas. The third community of the upland area consists of the lower elevation site around the wetland areas. This upland area consists of a transition community from the upland to the wetland species. Some of the higher organic matter upland areas contain some wetland vegetation that are remnants of the wetland plant community prior to the site disturbance or erosion. The upland tends to lack the wetland hydrology due to the landscape position. The vegetation surrounding the wetland areas has an overstory of Red Alder, Big Leaf Maple and an understory of Red Elderberry, Himalayan Blackberry, and Vine Maple. SOILS: The soil survey of King County lists the entire area as of the Alderwood series. An on -site inspection by a Registered Professional Soil Scientist determined that the area is not of the Alderwood series, but an inclusion of Indianola into the Alderwood map unit. Indianola soils range from loamy sand to sand; this explains why this site was probably used as a borrow 14 pit. Indianola soils, if they are of good sand quality, are useful as construction material. Once the site was used as a barrow pit, vertical slopes were left and the Indianola soils tend to erode down the steep slopes. Indianola soils are well drained soils, and not on the hydric soils list. IMPACTS: The proposed use of the site is to construct five single family residences. Presently the residences are to be constructed, four along Slade Way, and one house having access off South 160th Street. Several factors need to be taken into account in assessing the potential impacts of development . The proposed construction of houses, regardless of location, will require the filling of some of the wetlands. Houses constructed in the western uplands will need an access road, which will impact the wetlands. Furthermore, the geotechnical reports recommend dewatering the hillside to maintain slope stability for the houses and the roads. The dewatering will likely drain the wetlands. Geotechnical reports reference slope stability and slides in the area are documented by Dames and Moore in 1961. Dewatering of this site may be required regardless of house construction. 15 RECOMMENDATIONS: The following recommendation s are offered as an alternative that will allow construction of the five homes, dewatering of the site and maintain the values and functions. of the wetland area. It is understood that the wetlands will be impacted but the enhancement recommendationbs should stabalize the area and provide for the long term wildlife habitat potential of the site. The main function of the wetlands is for song birds, recreation and supplying surface water. Dewatering of the area and construction of the houses could be performed with no significant loss in these functions. The construction of a small open water pond fed by water from the dewatering system or the municipal supply would provide perennial water for wildlife. Dewatering would pipe the groundwater directly to the storm sewer. The water source for downstream water quality would be unimpacted. There would be a loss in food production from the wetland, but the small size of the wetlands provides minimal food production. Enhancement plantings could be made to provide habitat. The invasive non - native species, Himalayan Blackberry, would be removed. The present hydric soils, especially the organic, would support a wide variety of vegetation including the present wetland plants. Over time, the obligate wetland species would be replaced by facultative species. The facultative species would be planted as 16 part of the enhancement planting and provide a greater source of food than is present today. The present situation has invasive species taking over the site. Human intrusion, garbage and debris are common, and much of the wetlands are disturbed by the woods road. The overall habitat could be improved through an enhancement plan. It is recommended that the house sites be located along Slade Way and 160th St. to minimize the impact to the wetlands. A conceptual enhancement /mitigation plan will provide for plantings and a perennial surface water supply. A conceptual drawing can be provided should the city recommend this venue. 17 \\\\ .."...••••.........+-..■ , . 1 *v.44,31144 I I I • • )1 „ ?•; • .."1 •,••• ,•• !Me • - • SOUTTICEN TER St !OPTING CEN TER •1 1 CP • f03.14-,10 m,0 CM r Illt2r.11 1 I 1.4".01) it - CM CM I . ..... 1 I ...• CP CM C-2 t 6:k • FIGURE 1, VICINITY MAP MAP JOB # BREDBERG & ASSOCIATES,INC. Gig Harbor, Washington 1 . ! 1 1. ►Ij tQ G t1N =►.yy , t 1 tr 01� 1 el P3 En • O • H O c.n H tzi H •• til }1• WETLANDS SURVEY J -Di WETLANDS WERE DELINEATED BY A.J. BREDBERG 8 WETLANDS BIOLOGIST, ON APRIL 5, 1992 ANO i• 0 LOCATED BY JOHN E. CRAMER, P.L.S. ON APRIL 7, 1992: g e i' PP. Ali T. s!•' • 7 • •..., •. •% ;-'t ', _ 1. 1., WETLANDS MAIN AREA LESS UPLAND "A' NET AREA WETLAND "B" AREA WETLAND "C" AREA TOTAL WETLAND AREA 12,025 S.F. 378 S.F. 11,647 S.F. 518 S.F. 1,011 S.F. 13,176 S.F. SCALE :1" =30' BEARING DATUM: KING COUNTY ENGINEERS WEST LINE OF NW 1 /A, SEC.26. T.23N.R4E, WM. CONTOUR INTERVAL = 4'. BENCH MARK: MH 26 -19, N. INV. ELEV. = 248.00'. S1RAN,NT PARCEL MAIMS ARE OLD PARCEL Nl•NERS. DAUCIZED PARCEL WNW* MC NOI MCC. NUUIEAS. WETLANDS BIOLOGIST: ANTHONY J. BREDBERG P.O. BOX 1337 GIG HARBOR, WA. 98335 • thligat MAY1 5 1392j CV 43 TUKWILA PLANN1146 DEPT. IDSCAPED ;ROACHMENT 0 • v41:0C' S88 03'22"E SHED HEMLOCK z 0 0" HEMLOC • 30 HEMLOCK 20 .H MLOCK Locri.p44 D A werLA0b vle.-TuNPYD 1=3 Revised Wetland cation Map Slade Way & S. 160th St.' Bredberg & Associates, Inc. Gig Harbor, Washington Soo FEET 14,0t6 zf )7'15 sc 90o sc Rtly6CHAP/ 2 0.48/E I / • • ' • • . • 0" • HEMLOCK EMLOCK 5" HE LOCK \ • MAPLE AAPLE 4E1ALOcK 50 ./L49 L48 ES L47 L54 LOCK L5 0 E 1.0' pi EASEMENT 20 CEDA MH 26-18 0114 EL. 240.60 13 PIPE V STEEL 44 2 PIPE V STEEL V 2 PIPE 0' STEEL S 2 pt240.70 22" MAPLE L71 \3/1:70 10./L 9 Rz_-355.62. T-..14i .19 L=268.8' 14- Fig 20 .APLE MAPLE .15" HEML 14.134 26- 9 NH EL 05.111 PIPE •STEEL N 41.0 ' PIPE V STM. 5 LE mt. VSTEEL.id VA 240.1 S EV(.01 NOW 03'22-0 334.00' 630 FD 112; Tr, W/CAP FIGURE 4:CITY OF TUKWILA WETLAND MAP JOB# 1111 Locations of Inventoried Wetlands in the City of Thkwila BREDBERG & ASSOCIATES, INC Gig harbor, Washington o ,45 11 I� II •• :11:•'•11::1' • [•... Fuvinr ■ •• • ukwil • • • • .BM II II• II II 315 • • • • Riyerton•II \ 11• I I • •1 u • • BM 292 I1 4 •'�7 : ArnC Tann 0 • _,•••_ ••,_:_._•t�1.0;•;10,1::;0,•.";4°.!.„-,1„-- Iowa TAC ORT NI La FIGURE 5: BREDBERG & Gig Harbor li IABrlecoe KING COUNTY SOIL INVENTORY ASSOCIATES, INC. , Washington • • H 2 - Wetland # A Food Chain Support Figure 2. WETLAND RATING FIELD FORM FOR THE CITY OF TUKWILA Date 1/-/1" 7S -100% of WL covered w/ emergent vegetation Score = 3 50-75% of WL covered w/ emergent vegetation Score = 2 25 -50% of WL covered emergent vegetation Score =1 Score 3 Nutrient Transport WL associated w/ perennial watercourse Score = 3 WL associated w/ ephemeral watercourse Score = 2 Isolated WL (closed depression) Score= 1 Score Buffer (barrier function) (consider area w /in 50 feet of wetand edge) Dense forest or shrub = 75 -100% Score = 3 Dense forest or shrub Dense forest or shrub = 50-75% Score = 2 = 25 -50% Score =1 r ov y p«{1^s Score �- Habitat Di3 or more WL classes, one of which is Open Water Score = 4 1 WL class Score =1 Size of wetland: >7 acres Score = 5 0tolacre Score =1 a For total score, multiply sub -score for diversity by sub -score for size. Total Score >5 to 7 acres Score = 4 3 WL classes w/ no Open Water or 2 WL classes w/ Open Water Score = 3 >3 to 5 acres Score = 3 2 WL classes w /out Open Water Score = 2 Sub -Score a. 1 to 3 acres Score =2 Sub -Score 1 APPENDIX A: TUKWILA WETLAND A RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON Habitat (cont.) Percentaee of Forested Wetland: 75- 100% of WL is forested Score =4 50- 75% of WL is forested Score =3 25 -50% of WL is forested Score = 2 Score Duffer Habitat (consider area within 100 feet of wetland edge) Total of all relevant scores (check those that apply): A. Diverse forest or shrub B. Open forest or grass with occ. shrub =75- 100% score = 4 = 50-75% score = 3 ✓= 25-50% score = 2 =10 -25% score =1 = 75 -100% = 50-75% ✓ = 25 -50% score = 3 score = 2 score = 1 C. Pasture/herbaceous = 75 -100% '= 50 -75% score = 2 score = 1 Score y Surrounding land use: (outside of WL buffer, w/in 100' fat. Multiply percentage of arca in each category.) a. forested b. shrub or unmaintained grassland c. active agriculture/grass Score = 3 Score = 2 Score =1 d. urban: residential maintained lawns Score = -1 a and or b total 90% Score = 3 e. urban: industrial/commercial 1 Score = -2 Score a and or b total 50-90% a and or b total 25- 50% Score = 2 Score =1 Score 0 unioue teaturea (in wetland): ( checK those appropriate) raptor nest structures Snags >= 10 inches dbh, >20 feet tall Snags <10 inches dbh or beaver or muskrat lodges Fallen logs Perches Score =3 for each Score = 2 if present Score =1 for each Score Presence of water. Permanent Seasonal Score= 3 Score = 2 If permanent water is greater than 2 feet deep during driest season, add 2 points Score a p9.2 APPENDIX A: TUKWILA WETLAND A RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON • pg.3 • Wetland # 8 Food Chain Support Figure 2. WETLAND RATING FIELD FORM FOR THE CITY OF TUKWILA Date 1/-14-I2- 75 -100% of WL covered w/ emergent vegetation Score = 3 50-75% of WL covered w/ emergent vegetation Score = 2 25 -50% of WL covered emergent vegetation Score =1 Score Nutrient Transport WL associated w/ perennial watercourse Score = 3 WL associated w/ ephemeral watercourse Score = 2 Isolated WL (closed depression) Score =1 Score Buffer (barrier function) (consider area w /iri 50 feet of wetand edge) Dense forest or shrub Dense forest or shrub Dense forest or shrub = 75 -100% Score = 3 = 50 -75% Score = 2 = 25 -50% Score =1 Score -Z Habitat Di m as y: 3 or more WL classes, one of which is Opca Water Score = 4 1 WL class Score =1 Sjze of wetland: >7 acres Score = 5 0 to 1 acre Score = 1 For total score, multiply sub -score for diversity by sub -score for size. >5 to 7 acres Score = 4 3 WL classes w/ no Open Water or 2 WL classes w/ Open Water Score = 3 >3 to 5 acres Score = 3 2 WL classes w /out Open Water Score = 2 Sub -Score g- 1 to 3 acres Score = 2 Sub -Score Total Score • APPENDIX A: TUKWILA WETLAND 6 RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON Habitat (cont.) Percentaee of Forested Wetland: 75- 100% of WL is forested Score = 4 50- 75% of WL is forested Score = 3 25 -50% of WL is forested Score = 2 Score Duffer Habitat (consider area within 100 feet of wetland edge) Total of all relevant scorn (check those that apply): A. Diverse forest or shrub =75 -100% score = 4 = 50-75% score = 3 . = 25-50% score = 2 ✓ =10 -25% score =1 B. Open forest or grass with occ. shrub C. Pasture/herbaceous = 75 -100% = 50-75% ✓ = 25 -50% score = 3 score = 2 score = 1 =75-100% �= 50 -75% score = 2 score = 1 Score 3 Surrounding land use: (outside of WL buffo, w /in 100' feet. Multiply percentage of area in each category.) a. forested b. shrub or unmaintained grassland c. active agriculture/grass Score = 3 Score = 2 Score =1 d. urban: residential/maintained lawns e. urban: industrial/commercial — 1 Score = -1 Score = -2 S c o r e a and or b total 90% a and or b total 50-90% a and or b total 25- 50% Score = 3 Score = 2 Score =1 O Score unique features on weuana): (neck tnose appropriate) raptor nest strucwres Snags >= 10 inches dbh, >20 feet tall or beaver or muskrat lodges Score= 3 for each Snags <10 inches dbh Fallen logs Perches Score = 2 if present Score =1 for each Score 0 Presence of water: Permanent Seasonal Score =3 Score =2 If permanent water is greater than 2 feet deep during driest season, add 2 points Score -Z - p9.2 APPENDIX A: TUKWILA WETLAND 8 RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON • ■ — _ Water Storage Functions 'vocation in watershed: (If wetland has no inlet or outlet, Score = 0) middle third upper third Score = 3 Score = 2 lower third Score =1 Score age: Is surface water stored in this wetland? yes Score = 3 $ize of wetland: >7 acres Score = 5 0to1acre Score =1 >5 to 7 acres Score = 4 no Score = 0 >3 to 5 acres Score = 3 For total score, multiply sub -score for storage by sub -score for size. Sub -Score O 1 t, ? :acres . Score = 2 Sub -Score Total Score O Water Quality Residence Time: No outlet Score = 3 movement in outlet but no movement evident in wetland Score = 2 Score 1 Veaetad 11 Density 75 -100% of WL covered w/ emergent 3vegetatt+on Score . 50-75% of WL covered w/ emergent vegetation Score = 2 25 -50% of WL covered emergent vegetation Score =1 Score WETLAND B TOTAL SCORE 14 BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON pg.3 • Wetland # C Food Chain Support Figure 2. WETLAND RATING FIELD FORM FOR THE CITY OF TUKWILA Date II-RD -9g. 75 -100% of WL covered w/ emergent vegetation Score = 3 50-75% of WL covered w/ emergent vegetation Score = 2 25 -50% of WL covered emergent vegetation a Score =1 Score Nutrient Transport WL associated w/ perennial watercourse Score = 3 WL associated w/ ephemeral watercourse Score = 2 Isolated WL (closed depression) Score =1 Score 1 Buffer (barrier function) (consider area w /in 50 feet of wetand edge) Dense forest or shrub = 75 -100% Score = 3 Dense forest or shrub = 50 -75% Score = 2 ?°‘4 h5 Dense forest or shrub = 25 -50% Score =1 Score 1 Habitat Diyami 3 or more WL classes, one of which is Open Water Score = 4 1 WL class Score =1 Size of wed: >7 acres Score = 5 0 to 1 acre Score =1 For total score, multiply sub -score for diversity by sub -score for size. >5 to 7 acres Score = 4 3 WL classes w/ no Open Water or 2 WL classes w/ Open Water Score = 3 >3 to 5 acres Score = 3 2 WL classes w /out Open Water Score = 2 Sub -Score aL 1 to 3 acres Score = 2 Sub -Score 1 Total Score APPENDIX A: TUKWILA WETLAND C RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON _ Habitat (cont.) Percentage of Forested Wetland: 75- 100% of WL is forested Score =4 50- 75% of WL is forested Score =3 25 -50% of WL is forested Score = 2 Score O Duffer Habitat (consider area within 100 feet of wetland edge) Total of all relevant scores (check those that apply): A. Diverse forest or shrub =75 -100% score =4 = 50-75% score = 3 . = 25-50% score = 2 =10 -25% score =1 B. Open forest or grass with occ. shrub = 75 -100% = 50-75% = 25 -50% score = 3 score = 2 score = 1 C. Pasture/herbaceous = 75- 100% = 50 -75% score = 2 score = 1 Score 4/ Surrounding land use: (outside of WL buffer, w /in 100' feet. Multiply percentage of area in each category.) a. forested b. shrub or unmaintained grassland c. active agriculture/grass Score = 3 Score = 2 Score =1 d. urban: residential/maintained lawns e. urban: industrial/commercial Score = -1 Score = -2 a and or b total 90% a and or b total 50-90% Score = 3 Score = 2 Score —1 a and or b total 25- 50% Score =1 Score O unique features lm weuand): (check tnosc appropriate) raptor nest structures Snags >= 10 inches dbh, >20 feet tall or beaver or muskrat lodges Score = 3 for each Score = 2 if present Snags <10 inches dbh Fallen logs Perches Score =1 for each Score O Presence of water: Permanent Seasonal Score = 3 Score = 2 If permanent water is greater than 2 feet deep during driest season, add 2 points Score a — p9.2 APPENDIX A: TUKWILA WETLAND C RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON • • ;: ......,..* Water Storage Functions Location in watershed: (If wetland has no inlet or outlet, Score = 0) middle third upper third Score = 3 Score = 2 lower third a Score =1 Score : Is surface water stored in this wetland? yes no Score = 3 Score = 0 Size of wetland: >7 acres Score = 5 0to1acre Score =1 >5 to 7 acres Score =4 >3to5acres Score = 3 For total score, multiply sub -score for storage by sub -score for size. Sub -Score 0 1 to acres . Score = 2 Sub -Score 1 Total Score Water Quality Residence Time No outlet Score = 3 movement in outlet but no movement evident in wetland Score =2 Score a Ve etation Density: 75 -100% of WL covered w/ emergent vegetation Score = 3 50-75% of WL covered w/ emergent vegetation Score =2 25 -50% of WL covered emergent vegetation a Score =1 Score WETLAND C TOTAL SCORE 17 BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON • pg.3 • • DATA FORM ROUTINE ONSITE DETERMINATION METHOD' Field Investigate Ss : .' • 1 t'e d lies Date. ii//5 /9 2 Project/She• 1 i('r r Mc State: 1' County. IC; Applicant/Owner. Le 1R,� kc, �.a Plant Community #/Name• �'/C 4Ak 4' - -A)t t4.A1 %P/4 i# s Note: It a more detailed sit description is necessary, use the back of data form or a field notebook. Do normal environriental conditions exist at the plant community? Yes No ✓ (If no, explain on back) oil q ra e( p.• f Has the vegetation, soils, and/or hydrology been sigflificantly disturbed? Yea V No (If yes, explain on back) v !d G to cs c P,r-I- Dominant Plant Species 1. skt.1.✓ k ea 6 6a J e 2. 0 11.., A/atf /r 3, ReJ 4i-UP 4. '5a /.►r.s.•, 5. Oa ter- Air al /` �<411 6. 7. 8. 9. 10. VEGETATION Indicator Status Stratum Dominant Plant Species 11. «✓ 12. c T 13. -4C- 5/5 14. O%SL /7' 15 16 17 18. 19. 20. Percent of dominant species that are OBL, FACW, and/or FAC Is the hydrophytic vegetation criterion met? Yes t/ No Rationale. /O D Indicator Status Stratum pp SOILS tM Series/phase: AY r •r / e o4/ '- /Nu c 1 Subgroup•2 Is the soil on the hydric soils lis Yes ✓ No Undetermined Is the soil a Histosol? Yes No Histic epipedon present? Yes No Is the soil: Mottled? Yes No • Gleyed? Yes- ✓ No Matrix Color: - M the Colors. 4 Other hydric soil indicators: /' a c e Q e r- Is the hydric soil criterion met? Yes ✓ No Rationale: HYDROLOGY Is the ground surface inundated? Yes ✓ No Surface water depth: / Is the soil saturated? Yes ✓ No Depth to free - standing water In pit/soil probe hole. List other field evidence of surface inundation or soil saturation. Is the wetland hydrology criterion met? Yes No Rationale: JURISDICTIONAL DETERMINATION AND RATIONALE Is the plant community a wetland? Yes ✓ No Rationale for jurisdictional decision. 1 This data form can be used for the Hydric Soil Assessment Procedure and the Plant Community Assessment Procedure. 2 Classification according to 'Soil Taxonomy.' APPENDIX B: TUKWILA WETLAND A DATA FORMS B -2 BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON DATA FORM 9 ROUTINE ONSITE DETERMINATION METHOD1 Field Inveatigatqr(s): [ . a - 15 le a Lc/'z Date: Project/Site' 1f. ( e rc 6 r Tk K.,, , • Ut /s /9 2 Le k�� ���,�; State: 4J4 County• AppllcantdOwner• ` Plant Community N/Name• G/e4-1,.0A A 1314,A,ci Note: If a more detailed sit& description is necessary, use the back of data form or a field notebook. Do normal environmental conditions exist at the lant gg mmunit ? Yes No t/ (If no, explain on back) p v (d 'a 'e / i • Has the veeqge,etation, soils, and/or hydrology been significant disturbed? Yes c./No (If yes, explain on back) v (1 5 ra v e/ 'f VEGETATION Indicator Indicator Dominant Plant Species Status Stratum Dominant Plant Species Status Stratum 1. 34 /Q l '7a/ /e FAG 11 2 P 12. 3. Rpct Elder .r r cu 6/5 13. 4. Ue_4 /ht, /.r 1 FRck 14 5. 1,.✓deo.✓ P(4� Pitch S 15 6. /fin✓/,04ay aw f6(a.k6er� cic 4 i .ae. 16 7. J J 17 8. 18. 9. 19 10. 20 Percent of dominant species that are OBL, FACW, and/or FAC /B Is the hydrophytic vegetation criterion met? Yes No L.,- Rationale: Series/phase: 2;/ d�` k "i ° (A. Is the soil on the hydric soils list? Yes Is the soil a Histosol? Yes No Is the soil: Mottled? Yes No Matrix Color: /'Y.e 49/v Other hydric soil indicators: Is the hydric soil criterion met? Yes _ Rationale: SOILS Subgroup•2 No c/ Undetermined Histic epipedon present? Yes No Gleyed? Yes No Mottle Colors. No t— HYDROLOGY Is the ground surface inundated? Yes No Surface water depth. Is the soil saturated? Yes No Depth to free - standing water in pit/soil probe hole. List other field evidence of surface inundation or soil saturation. Is the wetland hydrology criterion met? Yes No L/ Rationale: JURISDICTIONAL DETERMINATION AND RATIONALE Is the plant community a wetland? Yes No Rationale for jurisdictional decision' 1 This data form can be used for the Hydric Soil Assessment Procedure and the Plant Community Assessment Procedure. 2 Classification according to "Soil Taxonomy." APPENDIX B: TUKWILA WETLAND A DATA FORMS B -2 BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON DATA FORM _ ROUTINE ONSITE DETERMINATION METHOD1 Field Investigatorss): '2 . . i3 J'e 1e!`yt Date. J /-5 f 9 2 Project/Site• rc s f •f Tit K._. �; i._1�t State: t'4• County* !C 0 -41A Applicant/Owner. Le Rte• A `Id e- Plant Community #/Name• lihflt A Note: If a more detailed sit description Is necessary, use the back of data form or a field notebook. Do normal environmental conditions exist at the plant community? Yes No t/ (If no, explain on back) 6/J �j ? a ✓2 ( P'` Has the vegetation, soils, and/or hydrology been significantly disturbed? Yes ✓ No (If yes, explain on back) O a _re e ( p; f VEGETATION Indicator Indicator Dominant Plant Species Status Stratum Dominant Plant Species Status Stratum 1. ee46a 4.e leg-- t{ 11. 2. 12. 3. 13. 4. 14. 5. 15 6. 16. 7. 17. 8. 18. 9. 19. 10. 20. Percent of dominant species that are OBL, FACW, and/or FAC Ay? Is the hydrophytic vegetation criterion met? Yes k No Rationale* n SOILS Series/phase: /0‘' i. s Q� /D„'+ /4Iu�k. Subgroup•2 Is the soil on the hydric soils lisp Yes '-' No Undetermined Is the soil a Histosol? Yes No Histic epipedon present? Yes No Is the soil: Mottled? Yps v No Gleyed? Yes y No Matrix Color: 2.5 r .771 Mottle Colors. Other hydric soil Indicators: Is the hydric soil criterion met? Yes ✓ No Rationale: HYDROLOGY Is the ground surface inundated? Yes Nov Surface water depth: Is the soil saturated? Yes ✓ No Depth to free - standing water In pit/soil probe hole: 3 List other field evidence of surface Inundation or soil saturation. Is the wetland hydrology criterion met? Yes t/ No Rationale: JURISDICTIONAL DETERMINATION AND RATIONALE Is the plant community a wetland? Yes '"'"-r No Rationale for jurisdictional decision: 1 This data form can be used for the Hydric Soil Assessment Procedure and the Plant Community Assessment Procedure. 2 Classification according to "Soil Taxonomy." APPENDIX B: TUKWILA WETLAND B DATA FORMS B -2 BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON DATA FORM _ ROUTINE ONSITE DETERMINATION METHOD1 Field Investipatgr(s): 1. •1 - 13 lie .. iz'!'�i Date: Project/She. 11;11 c rc 5 l' Tk K�� . I.J' State: 4) 4" County Applicant/Owner. Le L& 4 o.t- Plant Community Name• We a�j* B C - P aA'd Note: If a more detailed site A kit: is necessary, use the back of data form or a field notebook. i 92 Do normal enviroor mental conditions exist at the plant community? Yes No (If no, explain on back) obi r 4 �- / p Has the vegetation, soils, and/or hydrology been significantl' disturbed? Yes L- No (If yes, explain on back) old j r c, - e / ,D -f VEGETATION Indicator Indicator Status Stratum Dominant Plant Species Status Stratum 1. i M- �'1 tIN !'] IA -k 1 e 1 14 11 2. '�A "r r e - 4/ 12. 3. a �k4,44 � sf /e Me C'- 13 4 14 5. 15 6 16 7. 17 8. 18 9. 19. 10 20 Percent of dominant species that are OBL, FACW, and/or FAC 3 3 Is the hydrophytic vegetation criterion met? Yes No r/ Rationale. �- % SOILS Series/phase: -1,./ �'`a.✓v (' Subgroup:2 Is the soil on the hydric soils list? Yes No v Undetermined Is the soil a Histosol? Yes No €/ Histic epipedon present? Yes - No Is the soil: Mottled? Yes No ----V- Gleyed? Yes No Matrix Color: /(7 Mottle Colors' Other hydric soil Indicators: v Is the hydric soil criterion met? Yes No Rationale: HYDROLOGY Is the ground surface inundated? Yes No Surface water depth. Is the soil saturated? Yes No Depth to free-standing water in pit/soil probe hole. List other field evidence of surface inundation or soil saturation. Is the wetland hydrology criterion met? Yes No l/ Rationale: JURISDICTIONAL DETERMINATION AND RATIONALE Is the plant community a wetland? Yes No Rationale for jurisdictional decision: 1 This data form can be used for the Hydric Soil Assessment Procedure and the Plant Community Assessment Procedure. 2 Classification according to "Soli Taxonomy." APPENDIX B: TUKWILA WETLAND B f.0 DATA FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON DATA FORM ROUTINE ONSITE DETERMINATION METHODI e5—I9 Field Investigat . r(s): - f I'e d.��'I'4 Date• 2 Project/Sfte• t ►I!!!i<� ° State: County• j Applicant/Owner. LP go. k' 4...1.= Plant Community 0/Name. We r/a.�it C -- 6✓t 154.-4 Note: If a more detailed shWdescription is necessary, use the back of data form or a field notebook. Do normal environmental conditions exist at the plant c mmunity? n Yes No ✓ (If no, explain on back) 5/d Has the vegetation, soils, and/or hydrology been significantly disturbed? Yes V No (If yes, explain on back) 4/ 8,, r^ „,r P. VEGETATION Indicator Indicator Dominant Plant Species Status Stratum Dominant Plant Species Status Stratum 1. St '— /.. , ri 7e Ci' /1 11 2. 5.414...” lc 4,43 c N� iii _6' 12 3 13 4. 14 5. 15 6. 16. 7. 17 e. 18 9. 19 10. 20 Percent of dominant species that are OBL, FACW, and/or FAC Is the hydrophytic vegetation criterion met? Yes v No Rationale* /o SO! S Series/phase: A O 1 `r 4f0 i`'t�4G Subgroup 2 Is the soil on the hydric soils list? Yes " No Undetermined Is the soil a Histosol? Yes V No Histic epipedon present? Yes Is the soil: Mottled? Yes V No Gleyed? Yes No Matrix Color: .2• st' Mottle Colors: Other hydric soil Indicators: Is the hydric soil criterion met? Yes No Rationale: t No -�/ HYDROLOGY Is the ground surface inundated? Yes -_f No Surface water depth: Is the soil saturated? Yes No r Depth to free - standing water In pit/soil probe hole* List other field evidence of surface inundation or soil saturation. Is the wetland hydrology criterion met? Yes ti No Rationale: JURISDICTIONAL DETERMINATION AND RATIONALE Is the plant community a wetland? Yes v No Rationale for jurisdictional decision: 1 This data form can be used for the Hydric Soil Assessment Procedure and the Plant Community Assessment Procedure. 2 Classification according to "Soil Taxonomy." APPENDIX B: TUKWILA WETLAND C DATA FORMS B -2 BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON TABLE 1. Vegetation listed by genus species, common name, and National Wetland Indicator (NWI) status for the wetlands and uplands. Genus species (Common Name) NWI RA WETLAND PLANTS TREES: Alnus rubra (Red Alder) FAC 25% SAPLINGS: NONE SHRUBS: Rubus spectabilis (Salmonberry) FAC 15 HERBACIOUS: Lysichitum americanum (Skunk Cabbage) OBL 10 Urtica dioica (Stinging Nettle) FAC 10 Oenanthe sarmentosa (Water Parsley) OBL 5 Equisetum arvense (Field Horsetail) FAC 5 TABLE 1(CON) Vegetation listed by genus species, common name, and National Wetland Indicator (NWI) status for the wetlands and uplands. Genus species (Common Name) NWI RA UPLAND PLANTS TREES: Acer macrophyllum (Bigleaf Maple) FACU 25 Alnus rubra (Red Alder) FAC 35 Pseudotsuga menziesii (Douglas Fir) UPL 20 Tsuga heterophylla (Western Hemlock) FACU 15 SAPLINGS: Acer circinatum (Vine Maple) FACU 5 SHRUBS: Osmaronia cerasiformis (Indian Plum) FACU 10 Sambucus racemosa (Red Elder) FACU 10 Rubus spectabilis (Salmonberry) FAC 10 VINE /LIANA Rubus discolor (Himalayan Blackberry) FACU 20 HERBACIOUS: Polystichum munitum (Sword Fern) FACU 5 Hedera helix (English Ivy) FACU 5 Urtica dioica (Stinging Nettle) FAC 10 Cc� CASCADE GEOTECHNICAL, INC. 12919 N.E. 126TH PLACE (206) 821.5080 KIRKLAND, WASHINGTON 98034 FAX: (206) 823 -2203 May 30, 1990 Job No. 9005 -13G Leroy C. Lowe P.O. Box 1241 Seattle, Washington 98111 Reference: Preliminary Geotechnical Investigation for Hillcrest Slade Way, South of South 160th Street Tukwila, Washington Dear Mr. Lowe: At your request we have completed a preliminary subsurface soils investigation for the above site. The following report summarizes our findings and offers preliminary conclusions and recommendations for the proposed project. Additional subsurface information will be required in order to develop detailed foundation design parameters. SCOPE Our investigation is based on review of existing geologic maps, a review of some records of work on nearby sites, a detailed reconnaissance of surface conditions, two (2) backhoe test pits, thirteen (13) hand augers, and four (4) laboratory tests to determine the percent organics. This report summarizes our findings on the subsurface soil and ground water conditions, and offers preliminary conclusions and recommendations on foundation design, slope stability, and drainage recommendations. It also offers recommendations for further work. May 30, 1990 Leroy C. Lowe Job No. 9005 -13G Page 2 CASCADE GEOTECHNICAL PROJECT DESCRIPTION We were provided with a topographic plan of the site at a scale of 1 " =30', which was prepared by Survey Professionals and dated 5/17/90. We were also provided with a preliminary development plan that was prepared by you, at a scale of 1 " =30', undated. We understand that the proposed project is to consist of the construction of five (5) single - family residences, with driveways to access the houses. One of the proposed residences on the upper half of a thirty (30) foot high, 2(H):1(V) another is located at the top of the same thirty (30) 2(H):1(V) slope. The remaining three residences are to on a gently sloping area at the base of the 2(H):1(V) proposed roadway, which will access the two (2) houses of the slope, angles directly up a 1.5(H):1(V) slope. is located slope, and foot high be located slope. A at the top We recommend that our office be engaged to review the final grading and construction plans once they become available in order for us to make further recommendations as required. SITE DESCRIPTION The site is located on Slade Way, just south of South 160th Street, in Tukwila, Washington. The site lies less than a half mile southwest of the intersection of I -5 and I -405, and is about 250 feet up the west side of the Green River Valley. Single family residences are located to north, west, and south of the site. Slade Way abuts the east side of the site. There is a north - flowing grass lined swale between the property and Slade Way. At the northeast corner of the site is an eighteen (18) inch CASCADE GEOTECHNICAL May 30, 1990 Leroy C. Lowe Job No. 9005 -13G Page 3 diameter corrugated metal culvert that empties water into the swale. The site is roughly square in shape, and is about 330 x 350 feet. There is a north -south trending slope face on the property which slopes down to the east; it is a thirty (30) foot high slope which is at slightly less than 2(H):1(V). The slope is steeper in places. There is a relatively flat area extending west from the top of the slope ranging from fifteen (15) to one hundred (100) feet wide. At the base of the slope, the ground surface continues to slope down to the east at a gentle angle. There is about sixty -four (64) feet of relief across the site, with the high point at the southwest corner and the low point at the northeast corner of the site. Soft, wet boggy soils were present from the base of the thirty (30) foot high slope eastward to Slade Way. There are at least four (4) springs that outlet at the base of the slope. Surface water from the springs combine to make two (2) small creeks; the water trickles eastward across the site to the grass lined swale at the eastern edge of the site. The two (2) creeks were each flowing at about five (5) gallons per minute at the time of our visit. Standing water was observed in several places on the site. The vegetation consists of hemlock, alder and maple trees that are one to two feet in diameter. Some pistol butting of the trees growing on the slopes was observed. In the soft boggy area which extends from the base of the slope eastward, undergrowth consists of nettles, skunk cabbage, horse tails, briars and brush. May 30, 1990 Leroy C. Lowe Job No. 9005 -13G Page 4 CASCADE GEOTECHNICAL SUBSURFACE SOIL CONDITIONS Site subsurface soil conditions were determined by excavating two (2) backhoe test pits on May 15, 1990, and thirteen (13) hand augers on May 23, 1990. Backhoe access was confined to the northern edge of the site due to the presence of soft, wet, organic soils. Test pit and hand auger locations were selected by an engineering geologist from our office and located by pacing relative to property lines, corner stakes, and other identifiable landmarks. The Test Pit Location Map is presented in Appendix A. Depths referred to in this report are relative to the existing ground surface at the time of our investigation. For detailed test pit logs, hand auger logs and soil descriptions see Appendix B. All soils were classified in the field according to the Unified Soils Classification System. A copy of this classification is contained in Appendix C. Laboratory results are provided in Appendix D. In general, soil conditions at the site consist of topsoil over poorly graded sands; east of the base of the slope the sands are overlain by one (1) to five (5) feet of peat and organic rich soils. At the top of the thirty (30) foot high slope, hand auger holes showed a layer of topsoil overlying fine to coarse grained sands. The topsoil was about six (6) inches thick and consisted of loose, organic rich sand with some silt. Underlying the topsoil was loose to medium dense, moist sand with minor silt and gravel. Hand auger holes on the slope face showed a similar sequence to that described for the top of the slope. CASCADE GEOTECHNICAL May 30, 1990 Leroy C. Lowe Job No. 9005 -13G Page 5 Hand auger holes located eastward from the base of the slope showed a layer of wet to over - saturated, soft peat and organic rich sand that ranged from six (6) inches to five (5) feet thick. Underlying the blanket of organic rich soil, we encountered wet to saturated, medium dense, mottled, gray fine grained sand with a trace of silt. In the area of the two (2) test pits, the mottled, gray sand was underlain by wet, dense, blue -gray sand. Test Pit 2 showed a dense, gray -brown sand with faint mottling at a depth of twelve (12) feet, underlying the blue gray sand. Moderate to heavy caving occurred in Test Pit /1 between four (4) and twelve (12) feet below the existing surface. Minor seepage was observed at eleven (11) feet below the existing surface in Test Pit #1. It appears that there is ground water at the base of the slope, as evidenced by the presence of at least four springs. The geologic Map of the Des Moines Quadrangle, Washington, by Howard H. Waldron, dated 1962 shows that the surface soils at the site consist of Recessional outwash of the Vashon drift. The soils we observed on the site are consistent with the geologic map. The site is located near the upper limit of a large area previously investigated as part of a major slide. We have reviewed some of the extensive documentation on this area. Laboratory Results Laboratory results indicate that there is about twenty -three (23) percent organics by weight for Hand Auger /10 at a depth of four (4) to five (5) feet below the existing surface. There was about two (2) percent organics by weight for the other three samples - CASCADE GEOTECHNICAL May 30, 1990 Leroy C. Lowe Job No. 9005 -13G Page 5 Hand auger holes located eastward from the base of the slope showed a layer of wet to over - saturated, soft peat and organic rich sand that ranged from six (6) inches to five (5) feet thick. Underlying the blanket of organic rich soil, we encountered wet to saturated, medium dense, mottled, gray fine grained sand with a trace of silt. The test pits showed that mottled, gray sand was underlain by wet, dense, blue -gray sand. Test Pit 2 showed a dense, gray -brown sand with faint mottling at a depth of twelve (12) feet, underlying the blue gray sand. Moderate to heavy caving occurred in Test Pit i1 between four (4) and twelve (12) feet below the existing surface. Minor seepage was observed at eleven (11) feet below the existing surface in Test Pit /1. It appears that there is ground water at the base of the slope, as evidenced by the presence of at least four springs. The geologic Map of the Des Moines Quadrangle, Washington, by Howard H. Waldron, dated 1962 shows that the surface soils at the site consist of Recessional outwash of the Vashon drift. The soils we observed on the site are consistent with the geologic map. The site is located near the upper limit of a large area previously investigated as part of a major slide. We have reviewed some of the extensive documentation on this area. Laboratory Results Laboratory results indicate that there is about twenty -three (23) percent organics by weight for Hand Auger 010 at a depth of four (4) to five (5) feet below the existing surface. There was about two (2) percent organics by weight for the other three samples - CASCADE GEOTECHNICAL May 30, 1990 Leroy C. Lowe Job No. 9005 -13G Page 6 Hand Auger #4, #6, and #8 at the chosen depths. Please refer to Appendix D for laboratory results. CONCLUSIONS The site is situated just west of an area where numerous landslides have occurred. The mechanisms that are responsible for the slides are complex and variable. Major remedial work has been done near the Tukwila interchange due to slide activity. Our slope stability analysis for the site will need to encompass the regional geomorphic setting as well as local conditions on the property. Our investigation shows that this site can be developed, however, it will be difficult and quite expensive. There are at least four (4) springs at the base of the thirty (30) foot high slope. Standing water and some surface flow was present from the base of the slope eastward. Most of the site which lies eastward from the base of the slope is covered with a thick blanket of organic rich soil which is generally unsuitable for any structural use. Some pistol butted tree trunks near the base of the slope indicated the presence of surface soil creep. The upland areas of the site appear to be presently stable against sliding. We saw no surface indication of slope instability, nor any subsurface indication of slope instability in our hand augers, however, the hand augers were limited to the upper five (5) feet of soil. With additional subsurface information we will be able to determine specific factor of safety parameters. The plans we were provided show two (2) proposed residences to be located near or on the slope. We observed evidence of soil creep on the lower portions of the slope. Foundations for these two CASCADE GEOTECHNICAL May 30, 1990 Leroy C. Lowe Job No. 9005 -13G Page 7 houses will need to be deep. We anticipate that a pile foundation will be required at these locations. The plans we were provided show a driveway that angles directly up the thirty (30) foot high slope. The slope is steeper than 2(H):1(V) in the proposed roadway location. The proposed driveway does not appear feasible due to the steepness of the slope. The proposed residences that will be located in the lower portions of the site will require special foundations and /or site preparation due to the presence of ground water and the abundance of organic rich soil. The portion of the site that lies east of the base of slope will require a drainage system to capture the springs at the base of the slope. Horizontal drains or other resources may be recommended as additional subsurface information becomes available. Additional subsurface information from the site will be required to determine specific factor of safety parameters and specific foundation design parameters. RECOMMENDATIONS Ground water and surface water are a major factor at this site. Much of the soil on the eastern half of the site was wet to saturated at the time of our study. Some of the subsurface soils consist of very fine grained sands with some silt. We recommend performing site preparation and excavation work during an extended period of dry weather to avoid excess costs and construction problems associated with soil deterioration. Very specific CASCADE GEOTECHNICAL May 30, 1990 Leroy C. Lowe Job No. 9005 -13G Page 8 additional recommendations are essential if work must proceed in wet weather. Foundation Design Parameters Additional subsurface information will be required before detailed foundation design parameters can be provided. Depending on our findings, and on the effectiveness of the recommended drainage, there are two general options for foundation design for the residences at the base of the slope. One option would be to leave the organic soils and use a pile foundation - timber piles, or auger cast piles. A second option would be to strip the organic soils, add structural fill, and use a spread footing foundation. The buildings that are to built at the top of the slope and on the upper portions of the slope will require pile foundations to carry the loads to site depth. Specific design parameters can be provided after additional subsurface information is obtained. Drainage Extensive drainage will be required at this site. To allow drilling access to the site, we recommend that a drainage system be installed along the base of the slope to capture the water from the springs. The drain should follow the base of the slope, at about an elevation 268' feet above sea level, as shown on the site plan we were provided. We anticipate that extensive additional drainage will be required prior to development of the site. CASCADE GEOTECHNICAL May 30, 1990 Leroy C. Lowe Job No. 9005 -13G Page 9 General Additional subsurface information and a full review of previous work in the area will be required before detailed foundation design parameters can be provided. We recommend that several test borings be done on the site - at least two (2) at the top of the slope and two (2) at the base of the slope. We would be happy to provide you with a proposal and cost estimates for this work. We recommend that we be engaged to review plans, observe site preparation, observe subgrade conditions, confirm that bearing soils have been reached, and observe and test the placement of structural fill. This is a recommendation for engineering review and goes beyond any testing agency involvement which may be required. We expect the on site soil conditions to reflect our findings; however, some variations may occur. Should soil conditions be encountered that cause concern and /or are not discussed herein, Cascade Geotechnical should be contacted immediately to determine if additional or alternate recommendations are required. This report has been prepared for the exclusive use of Leroy C. Lowe for specific application to the proposed development at Slade Way and South 160th Street in Tukwila, Washington, in accordance with generally accepted soils engineering practices. No other warranty, expressed or implied, is made. CASCADE GEOTECHNICAL May 30, 1990 Leroy C. Lowe Job No. 9005 -13G Page 10 Thank you for this opportunity to assist you with this project. Should you have any questions, please feel free to contact us at any time. Sincerely, CASC E GEOTECHNI orge Principal • • • En•'ineei+•��ic 4:�GISTLaV�•4l.: F -C2Cr \ .1/4e .&C,C2%14 E. George Ehlers Engineering Geologist EGE : pg APPENDIX A HILLCREST TEST PIT & HAND AUGER LOCATION MAP Sounl 2BO1}i STREET ® TEST PITS (05/15/60) + HAND ANGERS (05/23/90) $ FROM TOPOGRAPHC SURVEY BY SURVEY PROFESSIONALS & FROM SITE PLAN BY LEROY C. LOWE CASCADE GEOTECHNICAL, INC. 12919 NI 1261119ACE (2061121.5060 KMKIANO. WASHINGTON 96034 TAX: (206) 623.2203 Job N.. 1 SCALE 1 l - 5a 905.13G LOCATIONS ARE APPROXIMATE Dale /Own. Sy IIM RipF 05/29/90 t HLA L_ APPEND I X B HILLCREST TEST PIT & HAND AUGER LOCATION MAP sourii 142N srneer • 1 1 I 1 1,4•44 1 1 I I • • it) KAM+ • TEST PITS (05/15110) + HAM AUGERS (05123/90) $ FROM TOPOGRAPHIC SURVEY BY SURVEY PROFESSIONALS & FROM SITE PLAN BY LEROY C. LOWE CASCADE GEOTECHNICAL, INC. 12919 N E. 128TH PLACE (206) 82 14080 1UNKIANO. WASHINGTON 960)4 FAX: (206) 8212203 J No. 905.130 I SCALE (XI LOCATIONS ARE APPROXIMATE bete /Dwn. Sy 05/29/90 I ILA II T.P. 1 Soil Description & Classification T.P.- 2 Soil Description & Classification - 1'ORGANIC SAND; DARK BROWN, LOOSE, WET. (PT) 2.5'SAND; WITH TRACE SILT, GRAY, MEDIUM DENSE TO DENSE, WET, PROMINENT ORANGE MOT - (SP)TLES, FINE TO MED.GRAINED. 2.5- 12'SAND; WITH TRACE SILT, BLUE GRAY, DENSE, WET TO SATURATED, FINE TO MEDIUM GRAINED. (SP) MODERATE TO HEAVY CAVING FROM 4'- 12' MINOR SEEPAGE AT 11' -15 Notes: T.D. = 12.0' 0 -5 ■ -15 Notes: - 1'ORGANIC SAND; DARK BROWN, LOOSE, WET TO SATURATED.(PT) 1'- 2.5'SAND; WITH MINOR SILT,CRAY, MEDIUM DENSE TO DENSE, WET, FAINT ORANGE MOTTLES.(SP) 2.5'- 7'SAND; WITH TRACE SILT, BLUE GRAY, DENSE, WET TO SATURATED. (SP) -4417 12' SAND; WITH SOME SILT, BLUE GRAY, DENSE, WET. (SP) WRR 12'- 13'SAND; WITH MINOR GRAVEL, GRAY BROWN, DENSE, WET, FAINT ORANGE MOTTLES. (SP) T.D. = 13.0' TEST PIT LOG CASCADE GEOTECHNICAL A DIVISION OF CASCADE TESTING LABORATORY. INC. HILLCREST Date 05/23/90 1 Job No. 905 - .13G Dwn. By HLA Geo /Eng. Z. HA,- 1 Soil D.scripfior Classification HA.- 2 Soil Description & Classification 6 "TOPSOIL; G .�:i::; ,- ''-� •:��.: u, ••• �: ::::•:;: :: SILTY SAND WITH TRACE GRAVEL, BLACK, LOOSE, MOIST. 6'- 2' SAND; WITH TRACE GRAVEL, TRACE TO MINOR SILT, BROWN ! , LOOSE TO MEDIUM DENSE MOIST FINE GRAINED. (SP) - 5 SAND; WITH TRACE GRAVEL & D �:;..:::::� '- �� _ A... = �' ' �`:':'`•.8 =• ,:.;;,.;,�: ' `'"•`'• "+' •'`' •'ti j ; :; ';::.�•;,� �;t; � :•...�.j:. - 8 "TOPSOIL; SILTY SAND WITH TRACE TRACE GRAVEL, BLACK, ORGANIC, LOOSE, MOIST. "- 5' SAND; WITH TRACE GRAVEL, TRACE TO MINOR SILT, LIGHT BROWN, LOOSE TO MEDIUM DENSE, MOIST, FINE GRAINED. (SP) '' J:: l'" ` ` ::;:::; ;• ; ::: "'::: �i:: %;.;_•. .:; SILT GRAY BROWN, MEDIUM DENSE MOIST F ! FINE GRAINED. (SP) ! •7 T.D. = 5.0' T.D. = 5.0' Notes: Notes: H.A. - 3 Soil Description & Classification H.A.-4 Soil Description & Classification C --r7-.:_„; —tip _s §- -0- 3.5' PEAT; BLACK, VERY SOFT, G �•__4-4 �:� ►_-:,,' ±0 - 2.5' PEAT; BLACK, VERY SOFT, .' '-- ' �n .� 111. 1'= -4.: A t i. - -i „ 1 1 _ __ SATURATED. (PT) 3.5'- 5'ORGANIC SILTY SAND; BLACK �'= -.- IL - . 11 4,--- r. Vii_ _ . SATURATED. (PT) :; ;,, ' �' • '" ':i � ' I 2.5'- 5' ORGANIC SILTY SAND; DARK BROWN TO BLACK, LOOSE, SATURATED, FINE GRAINED. (SM -OL) I TO TAN, LOOSE, SATURATED, FINE GRAINED. (SM -OL) T.D. = 5.0' T.D. = 5.0' Notes: .Notes: HAND AUGER LOGS CASCADE GEOTECHNICAL HILLCREST A DMSION OF CASCADE TESTING LABORATORY, INC. Dat. 05/23/90 Job No. 905 - 13G Own. By HLA Goo /Eng.� H.A.- 5 Soil Description`' ClossiFication H.A.- 6 led Description & Classification D —,"_�:_ _ TO - 3.5' PEAT; BLACK, VERY SOFT, 0 71 0��- 4'" DUFF - 1 TOPSOIL; SILTY SAND WITH �:-, �4 = +::' -" ,111 ; =: '- 14.5'- SATURATED. (PT) 3.5'- 4.5'SILTY SAND; WITH ORGANICS TRACE GRAVEL, DARK BROWN, • t =: �= LOOSE, MOIST. 1'- 3'SILTY SAND; WITH ORGANICS & TRACE GRAVEL, DARK GRAY - BROWN, LOOSE, WET. (SM -OL) _ _ T.D. = 3.0' • DARK GRAY TO BLACK, LOOSE, SAT- URATED, FINE GRAINED.(SM -00 5'SANDY SILT; WITH SOME ORGAN. ICS, TAN, LOOSE, SATURATED, FINE GRAINED. (ML -OL) T.D. = 5.0' Notes Notes: H.A. - 7 Soil Description & Classification HA.- 8 Soil Description & Classification 0'77" � "5 _ e•`•'"" "#'II I■ ----A *6'= 0 - 6 "PEAT; BLACK, SOFT, WET. (PT) 1'3 "SILTY SAND; WITH ORGANICS, 0-- — —' -s -`--'- 7 0 - 6 "DUFF ; ; 1 --- ; 1 0.0 6 "- 3.5'ORGANIC SANDY SILT; DARK ∎1 ; ; BLUE GRAY, LOOSE, SATURATED, FINE GRAINED. (SM -OL) 113.1- 3' SANDY SILT; WITH ORGANICS, BROWN, LOOSE, SATURATED, FINE GRAINED. (OL) -3.5- 4'SANDY SILT; WITH ORGANICS, 'I 11 I, GRAY BROWN TO DARK BROWN, SOFT, WET TO SATURATED, FINE GRAINED. (ML -OL) 3'- 4'SANDY SILT; WITH SOME ORGAN- i_ ICS, LIGHT BROWN TO TAN, SOFT SATURATED, FINE GRAINED.(ML -OL) 4'- 5' SANDY SILT; WITH SOME ORGANICS I, DARK GRAY, SOFT, SATURATED. (ML -OL) 4'- 5'SANDY SILT; WITH ORGANICS, TAN, SOFT, SATURATED. (ML-00 LT. BROWN TO TAN, SOFT, SATURA- ` TED, FINE GRAINED. (ML -OL) T.D. = 5.0' T.D. = 5.0' Notes: .Notes:. HAND AUGER LOGS A DMSION OF MICASCADE GEOTECHNICAL HILLCREST CASCADE TESTING LABORATORY, INC. Date 05/23/90 Job No. 905 - 13G Dwn. By HLA Geo/ Eng. 9.../C H.A.- 9 Soil Description Classification HA.- 10 Soil Description & Classification 0— �,,—'0 — 6 "DUFF 0 .. .,0 .. .• ' } ` "; =, — 2'PEAT; BLACK, SOFT, WET. (PT) . -m", '6 "— 1'5ANDYSILT; WITH ORGANICS & 2'— 5'PEAT INTERLAYERED WITH SILTY MINOR SAND, TAN, MOIST TO WET jni SII `• •11 �� 1'— 2'SILTYSAND; WITH ORGANICS & -S .`'a TRACE GRAVEL, BROWN TO BLACK LOOSE TO MEDIUM DENSE, WET. (SM—OL) 2'— 5'SANDY SILT; TAN TO BROWN, '� '..-44")% ',_ — .... '•' SAND; BLUE GRAY, LOOSE, SAT - URATED, FINE TO COARSE GRAINED. (PT —SM) SOFT TO STIFF, SATURATED, VARIES FROM SANDY SILT TO SILTY SAND WITH DEPTH, INTER l` LAYERED WITH ORGANICS(PT) _ \ (Ml— SM —OL) •S T.D. = 5.0' T.D. = 5.0' Notes: Notes HA - 11 Soil Description & Classification 14A.- 12 Soil Description & Classification o',""....,,,,:,,,,. -S 0 - 6 "DUFF "DUFF 0 0— 6 `�••.6 "— 6"— '**;.4-, 5' SAND; WITH TRACE GRAVEL, 3' SAND; WITH TRACE GRAVEL, - TRACE TO MINOR SILT, RED BROWN, LOOSE TO MEDIUM DENSE, MOIST, FINE GRAINED. (SP) ( ) t? '� ?'•• ;tiff; TRACE TO MINOR SILT, LIGHT BROWN TO RED BROWN, LOOSE TO MEDIUM DENSE, MOIST, FINE GRAINED. (SP) 3' — 5' SAND; TRACE TO MINOR SILT, LIGHT BROWN TO GRAY, MEDIUM DENSE, MOIST, COARSE GRAINED (SP) T.D. = 5.0' T.D. = 5.0' Notes: : .Notes HAND AUGER LOGS CASCADE GEOTECHNICAL HILLCREST . A DMSION Of CASCADE TESTING LABORATORY. INC. Date 05/23/90 Job No. 905 — 13G Dwn.By HLA Goo/ Eng. �` H.A.- 13 Soil Descriptionc , Classification 14.A. - .,....ioil Description & Classification o —"m!.771 .....:' - 6"DUFF 0 — — — -5— 6 - 3'SAND; WITH MINOR SILT, LIGHT 7..7 7777 BROWN TO RED BROWN, LOOSE TO MEDIUM DENSE, MOIST. (SP) T.. . = 3.0' . Notes • Notes : - Soil Description & Classification Soil Description & Classification 0 — _ — — -5 — — • 0 — — — — -5— — Notes: Motes • HAND AUGER LOGS CASCADE GEOTECHNICAL HILLCREST A DIVISION OF . CASCADE TESTING LABORATORY, INC. Da te 05/23/90 Job No. 905 - 13G Own. By HLA Geo/ APPENDIX C UNIFIED SvILS CLASSIFICATkIN SYSTEM MAJOR DIVISIONS SYMBOL LETTER DESCRIPTION - COARSE GRAINED SOILS GRAVEL i GRAVELLY SOILS CLEAN GRAVELS : •• • �•• . + • • • e • : • GW Well- graded gravels or gravel -sand mixtures, little or no fines .# «, S: G P Poorly graded gravels or gravel -sand mixtures, little or no fines GRAVELS WITH FINES Sample Interval [r[rE • GM Silty gravels or gravel - sand-silt mixtures GC GC Clayey gravels or gravel- sand -clay mixtures SAND i SANDY SOILS CLEAN SANDS ••••.''' • ••. ••• SW Well- graded sands or gravelly sands, little or no fines ".i�; 1t : :Yti ". • $P Poorly graded sands or gravelly sands, Tittle or no fines SANDS WITH FINES : • °; SM Silty sands or sand -silt mixtures SC Clayey sands or sand -clay mixtures FINE GRAINED SOILS SILTS & CLAYS Liquid Limit Less Than 50 MI inorganic silts & very line sands, rock flour. silty or clayey fine sands, or clayey silts with slight plasticity CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays or lean clays � 1 1 i 1 1 1 1 OL Organic silts 4 organic silty clays o1 low plasticity SILTS & CLAYS Liquid Limit Greater Than SO MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils. elastic silts CH Inorganic clays of high plasticity, fat clays ,' ,',', OH Organic clays of medium to high plasticity, organic silts HIGHLY ORGANIC SOILS -:4� :r = - :_.-%- PT Peat or other highly organic soils TOPSOIL M ~ w-4 .. Humus & duff layer FILL �•� %� Uncontrolled. with highly variable constituents L SO DATUM NOTE I2"0.1). Split Spoon Sampler Sample Interval I[ Ring or Shelby Sampler sample Interval qu Simpler Pushed Sample Interval * Other Sample Type Sample Interval CASCADE GEOTECHNICAL A DIVISION OF CASCADE TESTING LABORATORY, INC. Sol DATUM NOTE 2 Water Level Date Recorded Ts Torvane Reading qu Penetrometer Reading IWater Observation Well Tip Elevation KEY CHART TABLE OF CONTENTS Scope Subsurface Conditions Conclusions Recommendations Site Preparation Erosion Control Drainage Horizontal Wells French Drains Foundation Design Parameters Access Drive Construction Monitoring General Appendix A Appendix B Appendix C Appendix D Appendix E Page 1 Page 2 Page 3 Page 4 Page 4 Page 5 Page 6 Page 7 Page 7 Page 8 Page 9 Page 10 Page 11 Test Pit Location Map Test Pit Logs Hand Auger Logs Test Boring Logs Laboratory Results CASCADE GEOTECHNICAL, INC. 12919 N.E. 126TH PLACE (206) 821-5080 KIRKLAND, WASHINGTON 98034 FAX: (206) 823.2203 August 27, 1990 Job No. 9005-13G Leroy Lowe P.O. Box 3972 Seattle, Washington 98111 Reference: Hillcrest Slade Way Tukwila, Washington Dear Mr. Lowe: As you requested, we have completed an additional subsurface study at the above site. This study is in addition to the previous preliminary geotechnical investigation dated May 30, 1990. The following report is an addendum to the previous report and provides specific and detailed recommendations for developing the site for residential homes. SCOPE Our previous site investigation was limited by access and the equipment used for the exploration. The scope of this report was to conduct an additional subsurface study of the site based on test borings to investigate the subsurface soil and ground water conditions. The recommendations provided here are based on the previous study, three (3) test borings and a review of the subsurface information for an area adjacent to this site and our understanding of the preliminary design plan. Only very preliminary developmental plans were provided for our review. We understand that five (5) residential homes are proposed • CASCADE GEOTECHNICAL August 27, 1990 Leroy Lowe Job No. 9005-13G Page 2 for the site with an access drive that enters the property from the north and extends up the steep slope in the center of the site. No grading plan with finished floor elevations has been developed at this time. We should be engaged to review the final grading and construction plans to provide any additional or alternate recommendations that may be necessary. SUBSURFACE CONDITIONS A detailed site description can be found in our previous preliminary report. The test pits and hand augers done for that report found sands and organic sands with some peat on the site. Seepage was noted from the toe of the slope and in some of the hand augers. Three test borings were done at the site between the dates of July 24 and July 25, 1990 using a skid-mounted hollow stem auger. The test borings were located on the site by an engineering geologist from our office by pacing relative to known landmarks or property boundaries. All borings were done in accordance with ASTM D-1586 sampling procedures and monitored continuously by an engineering geologist. Samples were described in the field in accordance with the Unified Soil Classification. Representative samples were returned to our laboratory for additional analysis. The test boring locations are shown on the map in Appendix A, as are the test pits and hand augers done previously. Test pit logs are found in Appendix B. Hand auger logs are found in Appendix C. Test boring logs are found in Appendix D. Laboratory results are found in Appendix E. The test borings showed fine to medium-grained sand with interlayered silt to the termination depth of between twenty-six CASCADE GEOTECHNICAL August 27, 1990 Leroy Lowe Job No. 9005 -13G Page 3 and one -half (26 1/2) feet and thirty -one and one -half (31 1/2) feet below the surface. The sand is medium dense to dense and wet to saturated. We noted some organic soils near the surface in the borings we observed. Ground water was found in all the test borings. We noted that the ground water appeared to be confined in a number of aquifers that had silty layers above and below. A hydrostatic head was noted in Test Boring #2 at a depth of twenty five (25) feet. Water reached the surface and then lowered to about five (5) feet below the surface when a layer of sand at twenty five (25) was encountered. Ground water monitoring wells were installed in Test Borings #1 and #2. Water level readings made a few days after the completion of the wells indicate that the ground water elevations are at approximately 282' in Test Boring #1 and 268' in Test Boring #2. The large difference in the two elevations indicates that there may be a number of separate, confined aquifers that exist at depth. The springs noted on the site appear to be at around elevation +274'. CONCLUSIONS It is our conclusion that the site is suitable for the proposed development if a deep seated foundation is used for support of the buildings and very extensive drainage is installed. All development of the site is potentially subject to damage from off - site events. Detailed design parameters will be required for the buildings and the proposed driveway that crosses the slope on the center of the site. The following recommendations are provided for the development of a design plan. We should be engaged to review the plan to provide any additional or alternate recommendations necessary. CASCADE GEOTECHNICAL August 27, 1990 Leroy Lowe Job No. 9005 -13G Page 4 The site is located above a known area of instability with a recent history of slope failure. We have reviewed some of the information available for the area downslope of this site. It is our conclusion that the Hillcrest site is presently stable. The proposed development should not adversely effect the slope stability if our recommendations are followed. Careful construction techniques and drainage control will be necessary to avoid any adverse effects of the proposed development. RECOMMENDATIONS Site Preparation The lower, eastern portion of this site is extremely wet with soft, organic soils noted at the surface. Working in this area will require careful and cautious techniques to avoid significant additional construction costs from disturbed soils. We recommend that drainage be installed prior to any site work. Detailed recommendations for drainage are discussed below. We recommend that the site work be done during a period of extended dry weather. Wet weather combined with the springs on site will likely cause additional construction costs. Light weight equipment should be used wherever possible. The soft, organic soils with surface water will deteriorate quickly when exposed to heavy construction traffic. We recommend that temporary construction access be provided to avoid difficulties with disturbed soils. Construction road traffic may include rocked roadways with quarry spalls and /or geotextile fabric or placing fill to raise the road grade. We recommend removing all vegetation and top soil from the proposed CASCADE GEOTECHNICAL August 27, 1990 Leroy Lowe Job No. 9005-13G Page 5 building areas. Depending on the final grades, it may be necessary to remove the peat as well. This will depend on the building and roadway locations and the proposed grading. We recommend that no cuts be made into the toe of the slope in the center portion of the site. Fill should not be placed on the slope face. Erosion Control Detailed erosion control will be necessary to avoid adverse off- site effects of the site development. We recommend that a detailed erosion control plan be prepared and implemented prior to construction based on our recommendations and in accordance with local codes. We recommend that a silt fence be placed around the perimeter of all construction areas to limit sediment movement off-site. The fence should be adequately supported to remain upright during all phases of construction. The lower edge of the silt fence should be buried in a six (6) to twelve (12) inch deep trench. Periodic maintenance of the fence will be necessary to confirm adequate sedimentation control. Stabilized construction entrances will be necessary to limit sediment movement off-site. The construction entrance should consist of a 100 foot long pad of two (2) to four (4) inch diameter quarry spalls that is at least one (1) foot thick. The pad should extend the entire width of the entrance and will need to be maintained if heavy traffic occurs. To control erosion on the site, especially on the steep slope, we recommend covering all exposed soils that are steeper than 1H:1V CASCADE GEOTECHNICAL August 27, 1990 Leroy Lowe Job No. 9005 -13G Page 6 with plastic sheeting. Mulching and /or seeding should be used for exposed soils after earthwork is completed. Permanent landscaping should be established immediately after completion of construction. We should be engaged to review the erosion control plan and to observe the installation of the control measures. Drainage Extensive drainage will be necessary to develop this site. We recommend that drainage be installed prior to any significant site excavation or earthwork. The exact drainage location and depths will depend on the building grades and conditions at the time of the drainage installation. We should be engaged to review the final plans to augment these recommendations if necessary. We recommend that a subsurface drainage system be installed at the base of the slope in the center of the site. At the present time, surface springs outlet across the base of the slope at approximately elevation 274'. We recommend that this water be captured and directed off the site by a combination of horizontal well points and a french drain with possible surface drainage channels. It may be possible to maintain a surface drainage system with the subsurface drains using a detailed drainage and grading plan. The buildings could be placed at a higher elevation with a low area left for surface drainage. We should be engaged to work with you in developing a grading plan if you anticipate this type of surface drainage. CASCADE GEOTECHNICAL August 27, 1990 Leroy Lowe Job No. 9005 -13G Page 7 Horizontal Wells Horizontal wells consist of a near - horizontally drilled shaft. Screening and tightline plastic pipe is installed inside the drill rod; the drill rod is removed, leaving the bit and the drain pipe. We recommend that horizontal wells be drilled into the base of the slope and extended horizontally to the property boundary. The location and number of the wells will depend on the amount of water encountered at the time of installation. We anticipate that wells would be installed on a 10 to 20 foot center to center grid, however the well will vary depending on conditions at the time of installation. The well heads should be captured and tightlined off the site to a suitable outlet. We should be engaged to observe the installation of the wells to provide immediate recommendations for the location and depth necessary. French Drains We recommend that a french drain be installed east of the toe of the slope in the center of the site. The french drain should be installed only after the horizontal wells are in place and tightlined off the site. The french drain should extend the entire length of the slope so that the water is directed off the site. The depth of the drain will depend on the final grading plan and where seepage is encountered during installation. We anticipate a minimum depth of around six (6) feet below the surface. The drain should consist of a six (6) inch diameter, perforated, rigid pipe that is bedded and backfilled with washed rock. It may be necessary to line the trench with a geotextile fabric to avoid future clogging from siltation. The depth of the french drain should be determined at the time of construction. CASCADE GEOTECHNICAL August 27, 1990 Leroy Lowe Job No. 9005 -13G Page 8 After construction, we recommend that footing drains be placed at the base of all footings or grade beams. The drains should be tightlined to the storm system. Footing drains should consist of four (4) inch diameter, rigid, perforated pipe that is bedded and backfilled in at least eighteen (18) inches of pea gravel. All roof drains should be tightlined away from the buildings separately from the footing drains. All paved areas should be curbed and graded to direct surface runoff away from the slope and to a catch basin that is tightline off the site. No drains should be allowed to outlet on the slope face in the center of the site. Foundation Design Parameters The proposed buildings on the lower portion of the site should be placed on a raised grade well above the surface water elevation noted during our study. The location of the buildings on the site will effect our recommendations for design. We recommend that the buildings on the lower portion of the site utilize a crawl space and avoid deep excavations for basements. We recommend that the proposed buildings be supported on pile foundations. The piles should penetrate into the native bearing soil noted below the surface organic soils. The piles should consist of either auger cast piles or driven timber piles. Auger cast piles twelve (12) inches in diameter and which penetrate the underlying native bearing soil at least ten (10) feet will be suitable for the support of vertical loads of 15 tons per pile. CASCADE GEOTECHNICAL August 27, 1990 Leroy Lowe Job No. 9005 -13G Page 9 A minimum length of fifteen (15) feet should be maintained on all piles. The length of the piles will depend on the soil conditions at the pile locations and grading done on site prior to the pile placement. The structural engineer should determine the pile spacing and grade beam design. Driven timber piles may also be used for support of the proposed buildings. There is some potential for off site damage from the driving process with this option. If you anticipate driving timber piles, we recommend that you conduct a detailed property survey of all surrounding structures before pile driving. Timber piles should consist of new, good quality timbers that conform to ASTM D25 -70 specifications. Driven timber piles may be driven to support a load of 20 tons per pile. We should be engaged to observe the installation of the piles to confirm adequate penetration for the design loads. Access Drive It appears from the preliminary design plans you provided that an access road is proposed from the north, off of South 160th Street. The access road will cross the steep slope to access the upper portion of the site. Another access road will serve the three lower lots from Slade Way. It appears from the preliminary plan that a cut and fill will be required for the driveway which crosses the slope face. Cuts of up to six (6) feet appear necessary for the roadway on the uphill side with fills of up to four (4) feet or more on the downslope side. We recommend that the entire road surface be placed on a subgrade of undisturbed native bearing soil. Placing fill on the August 27, 1990 Leroy Lowe Job No. 9005 -13G Page 10 CASCADE GEOTECHNICAL slope face will require extensive and detailed construction techniques that can be expected to be difficult and expensive. The cut faces should either be supported with a structural retaining wall or graded at a 2H:1V slope or less and landscaped. The proposed access road which enters the site off Slade Way appears to be located in an area of surface water and organic soils. We recommend that the organic soils be removed from within the proposed road subgrade area and a clean granular fill placed up to the subgrade elevation. It may be possible to use the on- site sand as fill once the organic soils have been removed. We recommend that construction access roads be constructed in the proposed access road locations. Site drainage as discussed above should improve construction conditions for the road. We recommend that we be engaged to review the final grading drainage plans to provide any additional recommendations that may be necessary. Construction Monitoring We recommend that we be engaged to observe the installation of all drainage and erosion protection at the site to confirm that the work is done in accordance with the design plans and our recommendations. We should observe the construction of the access roads, especially on the slope face, to confirm that the slope stability is not adversely effected. Installation of piles should be monitored by our office to confirm adequate penetration for the design loads. If you anticipate significant grading on the site, we recommend that we be engaged to monitor the placement of any fill. These recommendations are for engineering review and go beyond any testing agency involvement APPENDIX A ® TEST PITS (05/15/60) + HAND AUGERS (05/23/90) FROM TOPOGRAPHIC SURVEY BY SURVEY PROFESSIONALS & FROM SITE CASCADE GEOTECHNICAL, INC. 12919 N E 126TH PLACE (206) 821.5080 KIRKLAND, WASHINGTON 98034 FAX: (206) 823.2203 Job No. 905 -13G LOCATIOt Dole 05/29/90 APPENDIX B T.P. 1 Soil DsscriptS.._ & Classification -10 -15 Notes: 0 - 1'ORGANIC SAND; DARK BROWN, LOOSE, WET. (PT) 1- 2.5'5AND; WITH TRACE SILT, GRAY, MEDIUM DENSE TO DENSE, WET, PROMINENT ORANGE MOT - (SP)TLES, FINE TO MED.GRAINED. 2.5= 12'SAND; WITH TRACE SILT, BLUE GRAY, DENSE, WET TO SATURATED, FINE TO MEDIUM GRAINED. (SP) MODERATE TO HEAVY CAVING FROM 4'- 12' MINOR SEEPAGE AT 11' T.D. = 12.0' T.P. 2 Soil Description & Classification 0 -15 Notes: 0 - 1'ORGANIC SAND; DARK BROWN, LOOSE, .WETTO SATURATED.(PT) 1'- 2.5'SAND; WITH MINOR SILT, GRAY, MEDIUM DENSE TO DENSE, WET, FAINT ORANGE MOTTLES.(SP) 2.5'- 7'SAND; WITH TRACE SILT, BLUE GRAY, DENSE, WET TO SATURATED. (SP) 12'SAND; WITH SOME SILT, BLUE GRAY, DENSE, WET. (SP) 12= 13'SAND; WITH MINOR GRAVEL, GRAY BROWN, DENSE, DIET, FAINT ORANGE MOTTLES. (SP) T.D. = 13.0' TEST PIT LOG CASCADE GEOTECHNICAL A DMSION OF CASCADE TESTING LABORATORY, INC. HILLCREST Data 05/23/90 1 Job No. 905 - 13G 1 Own. By HLA I Goo /Eng. 96SZ UNIFIED `SOILS CLASSIFICAI SON SYSTEM MAJOR DIVISIONS SYMBOL MAJOR DIVISIONS SYMBOL LETTER DESCRIPTION COARSE GRAINED SOILS • GRAVEL i GRAVELLY SOILSGM ;... f ...• �..�••• CLEAN 4:44:.• GW Well- graded gravels or gravel - sand mixtures, little or no fines GRAVELS *:;• i . :!if1►! GP P Poorly graded gravels or gravel -sand mixtures, little or no fines GRAVELS * Silty gravels or grime, -sand -silt mixtures WITH FINES jji� GC Clayey gravels or gravel-sand-clay mixtures SAND i SANDY SOILS .. .. �� �� • CLEAN ,!...• :•• • e • SW Well- graded sands or gravelly sands, little or no fines SANDS +meter.: o:: +` %. , "•,titisti ? SP Poorly graded sands or gravelly sands, little or no finis SANDS SM Silty sands or sand -silt mixtures WITH FINES SC Clayey sands or sand-clay mixtures FINE GRAINED SOILS SILTS i CLAYS Liquid Limit Less Than SO M1 Inorganic silts & very fine sands, rock flour, silty or clayey fine sands, or clayey slits with slight plasticity Cl Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays or lean clays 1 1 1 1 1111 1 1 1 1 1 1 1 1 1 1 1 1 11 1 1 Ol Organic silts & organic silty clays of low plasticity SILTS & CLAYS Liquid Limit Greater Than SO 1 MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts CH Inorganic clays of high plasticity, fat clays � OH Organic clays of medium to high plasticity, organic silts HIGHLY ORGANIC SOILS -.4 .76.-_,z_ !_ '' "ce PT Peat or other highly organic soils TOPSOIL .. :^ Humus & duff Layer FILL ::....---...-•-.... ��� Uncontrolled. with highly variable constituents Y SOL DATUM NOTE I2" O.D. Split Spoon Sampler Sample Interval I( Ring or Shelby Sampler Sample Interval P Sampler Pushed Sample Interval * Other Sample Type Sample Interval CASCADE GEOTECHNICAL A DIVISION OF CASCADE TESTING LABORATORY, INC. SYM DATUM NOTE 2 , Water Level Date Recorded TS Torvans Reading qu Penetrometer Reading 1 Water Observation Wall Tip Elevation KEY CHART APPENDIX C HA- 1 Soil Descripti& . Classification H.A.- 2 _..- Soil Description & Classification 0 -.:.:. .::_: -4..:0 ;� . _�'•::,;•:: ,! ::�:_����= "''' "� 0�ti ' ': ", - 8 "TOPSOIL; SILTY SAND WITH TRACE GRAVEL, BLACK, ORGANIC, LOOSE, MOIST _� _ 8 - 5 SAND; WITH TRACE GRAVEL, TRACE TO MINOR SILT, LIGHT ' BROWN, LOOSE TO MEDIUM DENSE, MOIST FINE GRAINED. (SP) • 0 _r'.' �.-0 "' .. ." ' ', ::: '.; :_� _: '•_� : `'`` "'` - 6 "TOPSOIL; SILTY SAND WITH TRACE GRAVEL, BLACK, LOOSE, MOIST 6 "- 2' $AND • WITH TRACE GRAVEL, TRACE TO MINOR SILT, BROWN, LOOSE TO MEDIUM DENSE MOIST FINE GRAINED. SP ) 2' - 5' SAND; WITH TRACE GRAVEL & SILT, GRAY BRO!"M, MEDIUM DENSE, MOIST, FINE GRAINED. (SP) :;. ` ' T.D. = 5.0' _s T.D. = 5.0' Notes: Notes: HA - 3 Soil Description & Classification HA.-4 Soil Description & Classification 0 0 ►_ -:,� _'0 - 2.5' PEAT; BLACK, VERY SOFT, --v- ,� - 0 - 3.5' PEAT; BLACK, VERY SOFT, a•., 4 :': ,." R a. : • .i - li ii il SATURATED. (PT) 3.5L 5' ORGANIC SILTY SAND; BLACK_ '=.; :.;: .': of • •y'' I I ; ; 1 1 11 SATURATED, (PT) 2.5'- 5' ORGANIC SILTY SAND; DARK BROWN TO BLACK, LOOSE, SATURATED, FINE GRAINED. (S'1 -OL) TO TAN, LOOSE, SATURATED, FINE GRAINED. (SM -OL) T.D. = 5.0' T.D. = 5.0' Notes: .Notes: HAND AUGER LOGS 4::!!!3, CASCADE GEOTECHNICAL HILLCREST A DIVISION OF CASCADE TESTING tAIOMTOItr, INC. Date 05/23/90 Job No. 905 - 13G own. By HLA jG.o/EnQ. ► . HA . 5 Soil Description r�lassification H.A.- 6 l 'oil Description & Classification 0 -r:- -s — __-;:-.'0- 3.5' PEAT; BLACK, VERY SOFT, .--.-.A..0 - 4 "OIFF . 4 "- 1'TOPSOIL; SILTY SAND WITH -: = . -- 4"�- - +: a ' 1111 11111 =_ a ..- SATURATED. (PT) 3.5'- 4.5' SILTY SAND; WITH ORGANICS i•: TRACE GRAVEL, DARK BROWN, LOOSE, MOIST. 1'- 3'SILTY SAND; WITH ORGANICS & TRACE GRAVEL, DARK GRAY - BROWN, LOOSE, WET. (SM -OL) -s, T.D. = 3.0' DARK GRAY TO URAT D, FINE BLACK RAINED. (SM =OL) 4.5'- 5' SANDY SILT; WITH SOME ORGAN. ICS, TAN, LOOSE, SATURATED, FINE GRAINED. (ML -OL) T.D. = 5.0' Notes • Notes: HA- 7 Soil Description & Classification 1{A,_ 8 Soil Description & Classification 0 -, _. _ �''0 - 6 "PEAT; BLACK, SOFT, WET. (PT) 6'L 1'3 "SILTY SAND; WITH ORGANICS, 0 = 0 - 6 "DUFF — r — '7,r H " III VIII ��� " III " " "::,3.5L 6'- 3.5'ORGANIC SANDY SILT; DARK M BROWN, LOOSE, SATURATED, " FINE GRAINED. (OL) • " 4'SANDY SILT; WITH ORGANICS, BLUE GRAY, LOOSE, SATURATED, FINE GRAINED. (SM -OL) 1' 3'= 3' SANDY SILT; WITH ORGANICS, GRAY BROWN TO DARK BROWN, SOFT, WET TO SATURATED, FINE GRAINED. (ML -OL) 3'- 4'SANDY SILT; WITH SOME ORGAN- ;� DARK GRAY, SOFT, SATURATED. ICS, LIGHT BROWN TO TAN, SOFT II ii (ML -OL) 4'- 5'SANDY SILT; WITH ORGANICS, � H SATURATED, FINE GRAINED.(ML -OL) 4'- 5'SANDY SILT; WITH SOME ORGANICS I 1� '5 TAN, SOFT, SATURATED.(ML -OL) -5 .-„ LT.BROWN TO TAN, SOFT, SATURA- TED, FINE GRAINED. (ML -OL) T.D. = 5.0' T.D. = 5.0' Notes:- .Notes:, HAND AUGER LOGS CASCADE GEOTECHNICAL H1LLCREST A MASON Of CASCADE TESTING LABORATORY. INC. Oats 05/23/90 lob No. 905 - 13G lowThey HLA Geo/ Eng. 9./C H..&- 9 Soil Ooscriptiol, -& Classification 1{A,_ 10 Soil Description & Classification "DUFF 0—'1-'77'0 7== -• r_ do—a.7 '. - 2' PEAT; BLACK, SOFT, WET. (PT) 0 , ;. U - 6 '"..6 "- 1'$ANDYSILT; WITH ORGANICS & 5'PEAT INTERLAYERED WITH SILTY MINOR SAND, TAN, MOIST TO WET.:, .: " A 1 1 C('a (ML -OL) 1'- 2'SILTYSAND; WITH ORGANICS & _ -" : ; • :� ' TRACE GRAVEL, BROWN TO BLACK, LOOSE TO MEDIUM DENSE, WET. (SM -OL) 2'- 5'SANDY SILT; TAN TO BROWN,_- ....: -- - _4:;2'- 1 -_ __: - SAND; BLUE GRAY, LOOSE, SAT- URATED, FINE TO COARSE GRAINED. (PT -SM) SOFT TO STIFF, SATURATED, VARIES FROM SANDY SILT TO SILTY SAND WITH DEPTH, INTER, LAYEEDOWITH ORGANICS(PT) R -5 T.D. = 5.0' T.D. = 5.0' Notes: Notts • HA.- 11 Soil Description & Classification HA, -12 Soil Description & Classification o —i.•:••••• ,r'0 !•*.•''6 '' "'" a • :::A: ..";;;.;, '•`:,c :; - 6 "DUFF 07 7.77.70 - 6 "DUFF "- 5' SAND; WITH TRACE GRAVEL, 6 '- 3' SAND; WITH TRACE GRAVEL, '^ " " "`=; '. j '` • `::: TRACE TO MINOR SILT RED BROWN, LOOSE TO MEDIUM DENSE, MOIST, FINE GRAINED. (SP) TRACE TO MINOR SILT LIGHT BROWN TO RED BROWN, LOOSE TO MEDIUM DENSE, MOIST, FINE GRAINED. (SP) - 5' SAND; TRACE TO MINOR SILT, LIGHT BROWN TO GRAY, MEDIUM DENSE, MOIST, COARSE GRAINED T.D. = 5.0' -s, — T.D. = 5.0' Notes: .Notes: HAND AUGER LOGS CASCADE GEOTECHNICAL HILLCREST A omsloN Of CASCADE TESTING LAIIOMTORY. INC. Date 05/23/90 Job No. 905 - 13G [Dwn.Ry HLA Goon Eng. C H.A.- 13 Soil Descripori & Classification Soil Description & Classification 0 . ,..-...; k*:.•;:c4,:l:Ii) "at.itvit. 6"DUFF 0 .... - -. -5- - 6"- 3118L112; WITH MINOR SILT, LIGHT BROWN TO RED BROWN, LOOSE TO MEDIUM DENSE, MOIST. (SP) --, -5- - T. D. = 3.0 • Notes • Notes: Soil Description & Classification Soil Description & Classification 0 .... - - ... -5 .. --• 0' - - - -5 -. ... Notes • .Notes: HAND AUGER LOGS CASCADE GEOTECHNICAL HILLCREST A ONSION Of CASCADE TESTING LAIONATOPIY. INC. Dat• 05/23/90 L.- Job No. 905 - 13G Own. Sy HLA G.oEng.JY Project H1LLCREST Job No. 905-13G Date 07/24/90 Boring No. 1 Dwn. By AEM. Driller DRUM uruirrED Drill Tye* SKID MOUNTED HOLLOW STEM AUGER Glee/Eng. R. BLOMOUST Hole 0 4" ID. Fluid NOM loAJetl ordwog Depth Penetration a 2 71 Soil Description & Classification Notes ,ta .. o 9:1 • . a — 3 3 3 6 1SAND; LIGHT BROWN, LOOSE, DRY, TRACE SILT, TRACE . ORGANICS (ROOT FRAGMENTS). (SP) , — 07/24/90 — 5 —12.----.4 -.1 15 8 13 SAND, GRAY, MEDIUM DENSE, DAMP. (SP) 1 7 14 15 29 . SAND; GRAY, MEDIUM DENSE, DAMP. (SP) I23 e. .. _.d SAND, GRAY, MEDIUM DENSE, DAMP. (SP) , ... , . 25 12 1 28 ... SAND; GRAY, MEDIUM DENSE, MOIST. (SP) _ II L . .e.;;,..... , .... ILI; BROWN, DENSE, WET, TRACE SAND. (ML) ... . 30 1] id 17 33 1.1414 ores: 1. TEST BORING LOG 1 2 i CASCADE GEOTECHNICAL A 011/190N OF CASCADE TESTING LABORATORY, INC Peoria ,,c Project HILLCREST Job No. 905 -136 , Boring No. 1 3* • e E D o Depth Penetration Soil Description & ClauiFication Notes '0 a N Siretc I - - 35 15 28 28 56ynti :::_.:..a ..... SAND; BROWN, VERY DENSE, SATURATED. (SP) _ 6" HEAVE — - . ow TO = 31.5' —4 — Notes;, WATER TABLE AT 26.5' UPON WI_THDRAWL OF SAMPLER. PIEZOMETER INSTALLED_ 15' OF SLOTTED PIPE, MQNUMENT PLACED. MI CASCADE GEOTECHNICAL A DIVISION Of TEST BORING LOG Project HILLCREST Job No. 905-13G Dote 07/25/90 Boring No. 3 Dwn. By AEM Driller °REIM urhissrED Drill Type SKI) MOUNTED HOLLOW STEM PUGEF1 Geo/Eng. P. jEwEn. Hole 0 4" LD. 9uid NONE • .9 • -a E 0 4.1) .= a. • • C Penistration o 2 a Soil Description & ClossiFication Notes -0 . . 0 a . ' ,, ' _.: t;71-i- 4.-4_.- Is-ei----: :Far •Ngiv. i::.:::.:. ag PEAT/ORGANIC SAND; GRAY TO BLACK, COARSE GRAINED - 07/25/90 2 SAND, WET. (PT) SAND; WITH SOME SILT, GRAY, SATURATED, MEDIUM DENSE 17 ... 10 9 8 COARSE GRAINED, 8" WATER IN TIP. (SP) SAND; GRAY, SATURATED, COARSE GRAINED, INCLUDING te. 15 6 15 ,..1. ‘" SILT IN TIP. (SP) SAND; AS ABOVE. (SP) 4 6 7 13 SAND; LIGHT BROWN, MOTTLED, MEDIUM DENSE, MEDIUM T 25 8 1 FINE GRAINED, SATURATED. (SP) NO RECOVERY 30 9 14 23 T.D. = 26.5' Notes: TEST BORING ,N__ 1 • 1 LOG MI CASCADE GEOTECHNICAL A DMSION OF CASCADE TESTING tABORATORY INC 1 CASCADE TESTING LABORATORY. INC. TESTING & INSPECTION / ENGINEEPS i GEOLOGISTS •29if ti[ 'a•••. Pt, *CC ..�.�LaI.G vws.wc rOti fW3.' .204023••00 ORGANIC CONTENT - WATER CONTENT k. 12001 S23•6700 C VCR( YT 12001 as10•0411 r7 PROJECT, BORING HILL CREST DATE 05/24g0 JOB No. 9005 -13G NO. Sample or Specimen No. • r Tara No. w p .2 o 3 Tars plus wet sod Tars plus dry sod . , Water W w Tars Dry soil W s Water content w '/. % •/. •/. '/. •/. Sample or Specimen No. Tare No. Weight In prams Tars plus wit sod Tars plus dry soli Water W M . Tare Dry soil • Water content w •/s '/. % % % '/. ORGANIC CONTENT Sample or Specimen No. 4 6 8 10 Tars No. Weight In grams WEIGHT BEFORE BURN 100 s • • WEIGHT AFTER BURN 98 49 94 26 % ORGANICS BY WEIGHT 2% 2% 2% 23% % ORGANICS BY VOLUME 1 w 7 % 7 % 8 " 53 14 % % Remarks (tare plus wet soil) - (tare plus dry soli) w' /.. Ww x 100 100 s s x (tare plus dry sor) • (tars) Tecnnicsan Comoutsd by. Checked by, •ate)'/ HILLCREST TEST PIT & HAND AUGER LOCATION MAP SOdJ41 isory STRE-er sly TEST PITS (05/15/90) HAND AUGERS (05/23190) X TEST BONGS (07/2090 & 07/25/90) FROM TOPOGRAPHIC SURVEY BY SURVEY PROFESSIONALS & FROM SITE PLAN BY LEROY C. LOWE CASCADE GEOTECHNICAL, INC. 12919N 1 1267,IPIACI 17061071 SOW IN Itt AND, WASIONG ION 90034 17V 11081013 7103 Job No, 905.13G I SCALE LOCATIONS ARE APPROXIMATE 0eHt Ithoo. By 11,2"1. 06/03/90 MLA e- s, t 1 . ';71 f • I • • R-2H. LI h )r I r R-3 ' - • . 1 .2 :- 17.2, • L 1R-1.7.2 r..T1i,..:11-i.7.2 I- • I-2 I; j-1 i ! I" '-.I. II-1. --.- 1 L.., I I. LILL. 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I I I : ,. ..:sl. , ` '-'.1'1 :. : ••'••t ,. . , .:•:, • • I : . 9 R-1.72. • ..1 I!1"--i..li .....,. L... 12.0" 6 . • ••. .• _....... • , ,i 12. 2..2.......713.1! ',111 • T • z . . R.2.• :•,, FEES Efta • ft III 140111 • 11 • t • R • •-T ' 7 r. R-1-9.6- • 7.2 R-1- R. 1 • .1 L. 9 .,1 i. " 1 ; R-1-12i0 - 1112D FINN •1. R•4 0 KWtU INTFR HAN61: t • . • . • .. ....,.. c, ; .L._..„..."'IL L -;-,,,-;-„R-1-12:0 1 1 , ,-.-1,r0..114,..• ..,..,, 1.0..•••■..t.s.elsti.rg-1,--ra.V...m.: ,....V..: ,_ `..... i • . I 1: paimma wpm, I • 71-1.... •.• L.:. •• • . ' ••.: I./ i...."7:-••• • ■., 1 r 1 '. !'.-.! I , .. C-1 - -•:! : .. • • SO 1. \ .\\ IIILLOZ611 :611T. ST 1 1. 1 1 1 LEROY C. LOW \ A.I.A. ARCHITECT \ \ S ITCT14 ST ..., -•". R.1.9.6:77, • 1' . .,::.1.1••..;:,:o•?•.-A-4,114....,.. .c.,6..,.71.. .... 1 R-1-9.6 t--7, 7-1 1 ,:•:.::.:..,.. N4----] :,..:,-; . ,.....1....1..... • ..... „..! i p ; .----. --1 i" •r-r: V't I IV) 1 - --. ,, ! c • ; r ■ 1 ___... or. .., ,..1.• \\"•1.,k. S 177ND Ps • S ¶1.0.10 9• I •„-- \.. .• 1/ 11 7/ I PO • 4•11T ST ° eT TORT DENT PARK R-A R-1- 20.0 R-3 j... P0 Ir. I Po 19:n0 5, -1-7.2 cP• •I SOUTHCENTER SHOPPING CENTER I \-1: .__. ..- •• I I CP . . ! • -.j CP 4 2 CM 4 •" '; " , art /NV OR • I i $ 1 1 I L4'11 .I I CM CM WOW • JICA C M I •AREA MVO -1rT7n CM vn • ; I CM r-77 - C-2 CM I k••••Kt U (10.,) 1 I ! I I 9 r I ; I I I I ! I LEROY C. LOWE A.Irk. ARCHITECT ' • •.; LEROY C. LOWE A.I.A. ARCHITECT P.O. BOX 1241 SEATTLE. WASHINGTON 08111 MEMORANDUM TO: DATE: PROJECT: SUBJECT: PHIL FRASER SENIOR ENGINEER APRIL 5 1991 HILLCREST UTILITIES DEAR MR. FRASER ENCLOSED ARE LETTERS OF UTILITY AVAILABILITY FROM VERY TRULY YOURS LEROY C . LOWE A.I .A ARCHITECT VAL VUE SEWER DIST. WATER DISTRICT #75 WATER FLOW CHART LEROY C. LOWE A.I.A. ARCHITECT r0 .D■ Ism •t *flLt. W *EMI ••III This certificate provides the Depar „ nt of Health and Build , S Land Development with information necessary to evaluate development proposals. no wri • n • Please return to: BUILDING & LAND DEVELOPMENT 150 Admrnntretron Budding Seattle. Wethmgton Ill10N 206 344 7100 KING COUNTY CERTIFICATE OF SEWER AVAILABILITY number name ❑ Building Permit ❑ Short Subdivision APPLICANT'S MANE ❑ Preliminary Plat or PUD ❑ Reron• or other PROPOSED USE Ri,i,msaVTlyA__ LOCATION 162161 4 S LADE Way (Attach sup 6 legal description if necessary) 1 SEWER AGENCY DIFORNATION et./ ACK 'II 1. a. ® Sewer service be be provided by side sever connection only to an existing site sewer QIV feet from the site and the sewer system has the capacity to serve the proposed use. OR b. Sever service will require an improvement to the sewer system off, ❑ (1) feet of sewer trunk or latteral to reach the site; and /or ❑ (2) the construction of • collection system on the situ, and /or ❑ (3) other (describe) 2. (Must be completed if 1.b above is checked) 11.M The sewer system improvement is in conformance with a County approved sewer comprehensive plan. OR b. The sewer system improvement will require • sever comprehensive plan amendment. 3. a. g The proposed project is within the corporate limits of the district, or has been granted Boundary Review Board approval for extension of service outside the district or city. OR b. Annexation or BBB approval will be necessary to provide service. 4. Service is subject to the followings a. Connection charges b. Easement(s), c. Others I hereby certify that the above sewer agency information is true. This certification shall be valid for one year from date of signature. Agency Name 1',ii►N 02I: F270 Title T J ritiVI E L. I ::Ii Signatory Name � � 1/' 9/ gna ture Date • PO bra 6.067 Stith( WA 90168 HILL CQE$T LIOAL DESCRIPTION That port,.. d the Northwest 1 of the Northwest 1 of "eetlen 16, Township )2 North, gauge 4 Oast, 1.11., 1a Sing Comet', Oa.hl.yteo, described es feline* CommenClhg et the Nest 1 corner of meld settles, thence along the Westerly line of .611 section, North 11014'13• vest 1600 feet, thence "oath 00')1')1• test 664 feet, thence North 0'14'13• West 140 feet, to the Tree Pent of Mgl•eing; thence North 80.21'31• vest ))4 bet, thee. North 8'14113• West 754.12 feet, themes South 3'21'21" Bast 1411 lest' thence North 0•14'1)• "eat 15).08 feet to the Soetheesterly lie* of South 160th Street et; thence shone said Southwesterly line, South 70.3'05' Bast 142.41 feet: thence South 76.07'40' Oast 01.41 feet to pole: which hers North 4'14'12' eeet from the Tres P int el Mgllnsingl thence Meth 8.14.1)' Mat 440.68 feet to the Tree Pint of Mglmetegl 14580 KNOW 00 portions of Lots 27. 21 and 29, "lock 2, NcNlcken Might., Division Member 1, sccerd3N to the unrecorded plat thereof)/ TOCIT111 OITO that portion of versIsd Booth 160th Street adjoining which attached by operation 10 1.w1 INCEPT that post!co thereof conveyed to the city of Tenets for Blade lay, by Me/ recorded ender S.cor /ing Number S 4444 1 an0 EXCEPT th.t portion thereof condemned In t.it.d Elston District Covert, eestsro Olstrlat of Oa.hl•yton, Norther.. Dieteton, Civil Case Number 41110p AND YCOPT that portion thereat described a. tallow1 Commencing at the vest 1 corner of said Section 261 Thence North 8'14'12• W est aloe, the West line of said ..atlen 1004.02 feet: thence "moth 3.21')1' Oast 230.00 feet to the Tree Point of beginning: thence Meth Sl'21')1' Bast 140 lest; thence North 9'14'1)' Bast 15).11 feet to the S outh Ilee of North 160th 8tr.stl thence North 7S45'0S' West •long . aid South line 141.34 feet to a point which 1. North 0•14'1)' vest tree the True Point of Mglnniegi theses South 0•14.111' "set 200 feet to the Tree Point or 109100 /qt 1100 slCE1T that portlos thereof described es fellow* . Co.menelsg at the West 1 corner of said Section 261 thence North 1.14'13' Most .long the West section line 1740 fed; thence South 11021'31' Nast 510 feet; thence North 6'14'13' vest 301.24 feet to the Tree Pint of M 1mnlnys thence continuing North 1.14'1)' best 1110 feet to the South. arty orgin of South 160th Street* thence South 70.51'85' Bast along said margin 69.4/ feet, thence Mouth 7447'40' East 71.24 feet to the Ink ion of •a11 margin with the 0s.0.rly margin of "lade May; theses 13•21'17' West eleng veld Westerly margin 148.211 feet) thence North 13.41'47• vest 111.111 feet to the Tree Polst e1 begleel.$. LEROY. C. LOWE A.IA. ARCHITECT Pe) .397Z • 8�6-'6 Wa 98QO? Rkvve -- 1,64.4¢Z3 12 S. 16 • Puget Western, Inc., LEGAL DESCRIPTION VVSD LID 26 ESMT THAT PORTION OF THE NORTHWEST QUARTER OF THE NORTHWEST QUARTER OF SECTION 26, TOWNSHIP 23 NORTH, RANGE 4 EAST, W.M., DESCRIBED AS FOLLOWS: BEGINNING AT THE WEST QUARTER CORNER OF SAID SECTION AND RUNNING THENCE ALONG THE WESTERLY LINE OF SAID SECTION, NORTH 0 °14'13" WEST 1600 FEET; THENCE SOUTH 89 °21'31" EAST 874 FEET TO THE TRUE POINT OF BEGINNING OF THE TRACT OF LAND HEREIN DESCRIBED; THENCE NORTH 89 °21'31" WEST 210 FEET; THENCE NORTH 0 °14'13" WEST 140 FEET; THENCE 'n NORTH 89 °21'31" WEST 334 FEET; THENCE NORTH 0 °14'13" WEST 354.92 FEET; THENCE SOUTH 89 °21'31" EAST 140 FEET; THENCE NORTH 0 °14'13" WEST 153.08 FEET TO THE SOUTHWESTERLY LINE OF SOUTH 160TH STREET SOUTHWEST; THENCE ALONG SAID SOUTH- WESTERLY LINE, SOUTH 70 °55'05 ",EAST 142.41 FEET; THENCE SOUTH 76 °07'40" EAST 145.48 FEET;' THENCE SOUTH 46 °22'50" EAST 178.14 FEET TO A POINT WHICH BEARS SOUTH 0 °14'13" WEST FROM THE TRUE POINT OF BEGINNING;,. THENCE SOUTH 0 °14'13" EAST 448.20 FEET TO THE TRUE POINT..OF BEGINNING; (ALSO KNOWN AS LOTS 25,26,27 AND PORTION OF LOTS 28 AND 29 IN BLOCK 2 OF McMICKEN HEIGHTS, DIVISION.NO. 1, AN UNRECORDED PLAT); SITUATE IN THE TOWN OF TUKWILA, COUNTY OF KING, STATE OF WASHINGTON. EASEMENT This Indenture made this •' day of N d /, 1974, between PUGET WESTERN, INC., a Washington corporation, erein called "Grantor' and the VAL -VUE SEWER DISTRICT, King County, Washington, a municipal corporation, herein called "Grantee "; WITNESSETH: That in consideration of the sum of Ten Dollars ($10.00) in hand paid, receipt of which is hereby acknowledged, and the performance by Grantee of the covenants hereinafter set forth, Grantor hereby grants to Grantee, without warranty of any kind, a right of way not exceeding 10 feet in width for the construction, maintenance, replacement and operation of the following described facility: A sanitary sewer line not exceeding 8 inches inside diameter, within and across the following described land situated in the County of King, State of Washington, to -wit: The south 10 feet of: * Lot 27 Block 2 McMicken Heights Division 11, unrecorded; less portion northerly of line beginning 301.24 feet north from the southwest corner; thence east to the east line; less street; ALSO, the south 10 feet of the east 135 feet of: * Lots 28 -29 Block 2 McMicken Heights Division 01, unrecorded; less beginning at northwest corner of Lot 29; thence south 200 feet; thence east 140 feet; thence north to the northerly line of Lot 28; thence northwesterly to beginning; less the east 70 feet; Except south 301.24 feet of Lot 28; * ALSO, the west 10 feet south of Slade Way of: _ Lot 26 Block 2 McMicken Heights Division #1, unrecorded; less street. This easement is granted on the following terms and conditions: 1. Grantee agrees that said sewer main will be buried at least five (5) feet beneath the natural surface of the ground at all points. • 2. Grantee agrees to notify Grantor 48 hours prior to beginning of construction by calling 454 -6363, extension 630, Bellevue, Washington. 3. Said easement shall include the right of ingress and egress to, upon and over and across said land to construct, maintain, operate, repair and replace said sewer line and all connections and appurtenances thereto, and also grants to Grantee the use of such additional area immediately adjacent to the above easement as may be necessary for the construction of said sewer, such additional area to be held to a minimum necessary for that purpose. The grant for use of additional area shall terminate upon completion and testing of said construction, or no later than December 31, 1974. 4. Grantee agrees to save and hold Grantor harmless from all loss or damage which may be due to the exercise by Grantee of the right herein granted, and from all claims for such damage by whomsoever made, and to indemnify Grantor for all such loss, damage or claims. 5. Grantor shall not be liable for any loss or damages to Grantee's facilities resulting from Grantor's use of the lands encumbered by this easement unless such loss or damage is due to negligent act or omission of Grantor. Grantor agrees to use reasonable care. 6. Grantor reserves the right to develop easement for any purpose not inconsistent with reserves the right to construct buildings over of Grantee, which consent Grantee agrees shall due regard t_ Grantee's facilities. and use the lands encumbered by this the rights granted herein. Grantor said easement upon securing the consent not be unreasonably withheld, having * SAID LOTS BEING A PORTION OF THE FOLLOWING DESCRIBED PROPERTY. (SEE ATTACHED DESCRIPTION). • 7. Grantor reserve. .he right to gran..; ,ccess right. ,o others along or across .e lands encumbered by this easement and ,rant any other right which is not inconsistent with the rights granted herein to Grantee. 8. Should the easement area be subsequently improved by Grantor or its assigns, Grantee agrees that it shall, at its sole cost and expense, replace or restore to its improved condition any such improvements which are damaged or destroyed as a result of Grantee's exercise of its rights of maintenance, repair or replacement. 9. Grantee agrees that in consideration to Grantor for said easement, Grantor shall be entitled to make connections to the sewer line at a future date at no cost to Grantor, its successors and assigns. G7 10. No assignment of the privileges and benefits accruing to the Grantee hereunder, 7 by operation of law or otherwise, shall be valid without the prior written consent of .4) Grantor. 11. The rights and obligations of the parties shall inure to the benefit of and fir) be binding upon their respective successors and assigns. 12. The rights hereby granted shall cease and determine whenever Grantee shall have permanently abandoned the use of its facilities accommodated by this easement. VAL -VUE SEWER DISTRICT PUGET WESTERN, INC. By ?tge.4F-gee STATE OF WASHINGTON ) ) ss. COl1NTY OF KING ) On this day ofitQ (/P l , 1974, before me, the undersigned, personally appeared E. HALL, to me known to be the President of PUGET WESTERN, INC., the corporation that executed the foregoing instrument, and acknowledged the said instrument to be the free and voluntary act and deed of said corporation, for the uses and purposes therein mentioned, and on oath stated that he is authorized to execute the said••ins,Xrument. ,.. N. ii.wit `.my hand and official seal hereto affixed the day and year first above • z. • •••w N•• 1 STATE OF WASHINGTON ) ) ss. COUNTY OF KING ) On this —1 day of JOJEMV iEk . , 1974, before me the undersigned, personally appeared -17..7. MNre.uc to me known to be the tunRNA(,47 — , of VAL -VUE SEWER DISTRICT, the municipal corporation that executed the foregoing instrument, and acknowledged the said instrument to be the free and voluntary act and deed of said corporation, for the uses and purposes therein mentioned, and on oath stated that he is authorized to execute the said instrument. Notary Public in •; the State of Was gton, residing at WITNESS MY HAND and official seal hereto affixed the day and year first above written. .%rl11J1 ,`0r' t • > • n an• or e tate of kyashington, or �+o- l�s2Ai. at �3 MOi •JEF> . 2 d 1 0Y, •• w •0 h; •' t 47 • ...... 14. 2 - • 1 i 1 lel IC- fS MW IV 4 re+ In 110•1 ow. •■•• • ...WI • a••••■ •••• ••••• 4. in. I.. •.. • • • ••• I. • •• .1a •••• NW*, AS BUILT I : ' rs1611%.1'M R.A?" ••■•••••••••■••••TPIO•T••11•AT•• • • • 240 • • • /MM !MEM. •••••••1•AO.I•••U11.1211.6* . Ilral - • _ M3 -• - Me ... • • TUKWILA L.I.D. 26 • • e-orit -sultarfittls -.... ,• ri ri ils NW I CM VP YOSHIDA, INC. -.. • • SANITARY SEWER SYSTEM r--•i-K-- 11•A.l0t.ir N4W1" ' 11111 C.1101.0 1.1.•••• • it 03• 1 A1 .11111, WI ilaCTON .• POWNWI.01MI IN 1 This certif.cate p ; (des the Department of Hea1b.. and Building a Land Development with information necessary to evaluate development proposals. Please return tot BUILDING & LAND DEVELOPMENT Parks, Planning & Resources Dept. 3600 - 136th PLACE Southeast Bellevue, Washington 98006 -1400 (206) 296 -6600 KING COUNTY CERTIFICATE OF WATER AVAILABILITY Do not write in this box number name ❑ Building Permit ❑ Preliminary Plat ❑ Short Subdivision ❑ Rezone or other APPLICANT'S NAYV GARDy c, LoWE vJ-v - VPPZ.J or PUD PROPOSED USE/ S /../6"E P.4.4t/Lr ( S- L.T Sfle&ti LOCATION.,/ S, /lo at- s , +-SJ qv . S. MAY J. 6 1300 j (Attach map s legal description if necessary) 1 1 1 1 1 1 0 1 1 1 1. 1 1 WATER PURVEYOR INFORMATION 1. 1 i 1 a. j hater will be provided by service connection only to an existing uu water main ZJ feet from the site. OR b. Water service will require an improvement to the water system oft E/(1) 1) ❑ (3) size .- 3 o o feet of water main to reach the site; and /or the construction of a distribution system on the site; and/or other (describe) 2. a. 0 The water system is in conformance with a County approved water comprehensive plan. OR b. The water system improvement will require a water comprehensive plan amendment. 3. a. (The proposed project is within the corporate limits of the district, or has been u granted Boundary Review Board approval for extension of service outside the district or city, or is within the County approved service area of a private water purveyor. OR b. 0 Annexation or BRB approval will be necessary to provide service. 4. a. OR b. _Water ie,'w -will be available at the rate of flow and duration indicated below at no less than 20 psi measured at the nearest fire hydrant .300 feet from the building /pocky (or as marked on the attached map): Rate of Flow Duration ❑ less than 500 gpm (approx. gpm) ❑ less than 1 hour ❑ 500 to 999 gpm ❑ 1 hour to 2 hours W1000 gpm or more FOR 19-2 -hours or more ❑ flow test of gpm Pother ❑ calculation of gpm (Commercial Building Permits require flow tent or calculation) Water system is not capable of providing fire flow. COMMENTS /CONDITIONS r,J/t7g...e_ 4 J7 .t /41.4..s7. Lvop(. /1MN7-..., w A i/t.LavT 7 P /',s a Last , I hereby certify that the above water purveyor information is true. certification shall be valid for one year from date of signature. • KING COUNTY WATER DISTRICT 1 75 Agency Name. Supervisor of Engineering & Administration F 278 Title gnatory Name This i- gnnl'ure Date . <t 4'r r:ir",� it:'7'.sS1jf1'Egri A ; �N91lit.MR � �'!:� A?yT' S:(y �2t.; .. �.. ., ��. f...;�.... r. i•t •.(- .,.r,... ..21't• +;i'"'1` "' +fir .'-1. �• C .t.. t., ua�. u: i:.', L.::`.:, od.[.'... s,:....• Sn:✓; 5%%. ct<, �;. i.,,. e. i.:; r: En, s • <r2,,..S.fa'.::'sLSF'.rt::ts:5 ��7!.C�:�.�'�.,`F ii?"'. vttebf2' c�..`• ta.. n.,. �.: �. rU. ,...,_..2r.,..:i�ir.�,.....:,Y. SM �S. �e�,. ...n,.�S;,'�,'a:u,.....,:i�,.. ,,...�+i:.9.i�....._a.,., .. ,:iu..,.�'w�r ...r'. , L L N z ✓ J ▪ ID "I I . 3 3 L L N 0 z O I � L -1- m L N 0 z D L L U) 0 z W 0 MORATORIUM WAVER REQUESTED 5 -21 -90 MORATORIUM WAVER GRANTED S.A.O. 7 -2 -90 m m A B.L.A. APPLICATION FILED 9 -6 -91 PLANNING COMM . HEARING 3 -26 -92 WETLAND SYUDY FILED 4 -20 -92 REASONABLE EXCEPTION REQUESTED 6 -15 -92 • iN3W.sn 0v 3N11 A IVON1109 "S •.l -.n aiV ?'S.�;wY }.s i J. 7.ii'.^.. ': 34Y . {.........:..ss.{.»..iP,...., ywPi.�..:,. ;.y; :..»..r tPMU.:'•`.. .:.�:.� 1R' `,i'xf+s A�. \��..�rr `pi.' .,.., :..:.. ., �, F..�c:..•.;.•wx- 9',. el, ;.c...�: INDEX COVER LETTER CHECK LIST APPLICATION FORM ADMINISTRATIVE PRD APPLICATION ENVIRONMENTAL CHECK LIST SOILS REPORT ZONING MAP VICINITY MAP UTILITIES : SEWER AVAILABILITY LETTER LEGAL DESCRIPTION EASEMENT SEWER SITE PLAN WATER AVAILABILITY LETTER WATER FLOW CHART GAS UTILITIES SIT PLAN SITE SURVEY PLAN SUGGESTED STRUCTUAL DETAILS : FOUNDATION ISOMETRIC FOUNDATION PLAN FOUNDATION DETAILS (ILLUSTRATION ONLY) ADDRESS LABELS FOR PROPERTY OWNERS KING CO, ASSESSORS MAP WETLAND DELINEATION STUDY nlcccZsT "5 :.h7.Yk- .:t:': A.411 =i4KATI V..11 t1'�fF`r'� t :l�t�nr riv.;f.'�^ �T1.'vw y�"YI v�vbq V r.a !: :c •Si•..ro.' -.. ii';hIPS;::y C. >"�r"Jk�" 1.,.,.4 ..'�. "T ... �N�... lr��'a:;MYL�4,...,... f�3^,... c,.. 1w^ Y:.... sl. �.....,_:, �5�1? v. �"'> dx,..,: .,......'..T_..,�,.,FS�:,.k!S?) HILL CPE$T L. RICK BEELER DIRECTOR , DEPT. OF COMMUNITY DEVELOPMENT 6300 SOUTHCENTER BLVD. SUITE 100 TUKWILA WA. 98166 DEAR MR. BEELER SEPT. 6, 1991 THE FOLLOWING DOCUMENTS ARE SUBMITTED IN SUPPORT OF A : BOUNDARY LINE ADJUSTMENT THANK YOU FOR ATTENDING TO THE PROCESSING OF OUR APPLICATION . WE LOOK FORWARD TO WORKING WITH YOU ON THIS PROJECT. LEROY C. LOWE A IA ARCHITCCT . . LEROY C. LOWE A.I.A. ARCHITECT P.O. BOX 1141 5EATTLC. WASHINGTON Sell • TUKWILA PLANNING COMMISSION TUKWILA WA. HILLCREST B.L.A. REASONABLE USE EXCEPTION GENTLEMEN JUNE 15, 1992 ON MAR. 26, 1992 THE TUKWILA PLANNING COMMISSION SPECIFIED THAT A WETLAND DELINEATION STUDY BE PROVIDED IN SUPPORT OF THE HILLCREST BOUNDARY LINE ADJUSTMENT APPLICATION. THIS STUDY WAS COMPLETED AND SUBMITTED TO THE TUKWILA PLANNING STAFF ON APRIL 20, 1992. WE ARE BEING DENIED REASONABLE USE OF THIS PROPERTY BY APPLICATION OF THE SENSITIVE AREA ORDINANCE. WE THEREFORE REQUEST A REASONABLE USE EXCEPTION BE GRANTED UNDER ART. 18.45.115 S.A.O. • ITEM (A) WEST PORTION OF PROPERTY UNBUILDABLE FOR REQUIRED ROAD TO SAME WILL NOT MEET FIRE MARSHALL'S STANDARDS; I.E. 15% MAX. ROADWAY SLOPE IS NOT POSSIBLE. ITEM (B) LOT #6 UNMARKETABLE BECAUSE OF SIZE, SHAPE, AND TOPOGRAPHY. (SEE ATTACHED REALTY LETTER .) ITEM (C) TO PRESERVE AND PROTECT THE WETLANDS WOULD UNREASONABLY THREATEN THE PUBLIC HEALTH , SAFETY , AND WELFARE. THIS WETLAND PUMPS WATER INTO THE DOWN SLOPE AQUIFER DESTABILIZING SLADE WAY AND THE DOWN SLOPE PROPERTY. (SEE REPORTS FURNISHED TO PLANNING COMM. MAR. 26, 1992) . THIS INFORMATION IS SUBMITTED IN SUPPORT OF OUR REQUEST FOR A REASONABLE USE EXCEPTION. WERE WE TO FOLLOW THE WETLANDS ORDINANCE, WE WOULD BE DENIED EVEN REASONABLE USE OF OUR PROPERTY OUR PROPERTY IS Z D F•___.-- _•TS, WE REQUEST 5 LOTS. SINCERELY YOURS, LEROY C . LOWE June 10, 1992 LeRoy C. Lowe, A.I.A. Architect P.O.Box 3972 Bellevue, WA 98009 Dear Mr. Lowe, You have asked me to assist in marketing your Hillcrest project in Tukwila. I have done so, and have been involved since May of 1990. More recently, you have asked for my opinion regarding the marketing if lot #6 of the Hillcrest project. My opinion is as follows: Lot #6, because of it's restrictive size, shape and topography, is not a desirable property and would be most difficult, if not impossible, to sell as a building site. My recommendation would be to put this lot on hold indefinitely. The balance of the property could be brought to the market place at a break even, or slightly better price. Please let me know if I can be of any further assistance. Sincerel Richard H. Osborne President 653 228th Avenue N.E., Redmond, Washington 98053 Phone (206) 868 -7100 or (206) 392 -1678, FAX (206) 868 -1750 ! LEROY C. LOWE A.I.A. ARCHITECT P.O. BOX 1241 •IATTI_a. WASHINGTON 00111 DARREN WILSON ASSISTANT PLANNER 6200 SOUTHCENTER BLVD. TUKWILA, WA. 98166 DEAR MR . WILSON h /GLCREST FEB. 18, 1992 WE HAVE ATTEMPTED TO DISCUSS THE "REAL AND PRESENT DANGER" OF THE SLADE WAY SLIPPAGE PROBLEM WITH YOU ON SEVERAL OCCATIONS YOUR LETTER OF JAN. 30, 1992 WAS RECIEVED BY ME THE EVENING OF FEB. 8, 1992, NEARLY A HALF YEAR AFTER WE HAD FILED OUR BOUNDARY LINE ADJUSTMENT APPLICATION. ( SEPT. 9, 1991 ) 1 APPEAL YOUR LETTER DIRECTING ME TO PRESERVE AND PROTECT THE SEEPS ON MY PROPERTY FOR THAT ACTION WOULD PERPETUATE A DANGEROUS SITUATION PLACING SLADE WAY IN PERIL. THE EXPENDITURE FOR WET LAND DELINIATION IS UNREASON- ABLE IN LIGHT OF THE CITYS DEFICIENCY IN HANDLEING THE SLADE WAY CONCERNS. • h /GLCIZe5T PAGE 2 WE APPEAL TO YOU THE STAFF AND TO THE CITY TO WORK WITH US TO PROVIDE FOR REASONABLE DEVELOPMENT OF OUR PROPERTY AND THE CITYS PROTECTION OF SLADE WAY, THE SANITARY SEWER , AND THE UTILITIES THEREIN. AS DISCUSSED IN THE ATTACHED LETTERS FROM : RESCO, BREDBERG, AND JOULE, YOUR IMMEDIATE ATTENTION TO SLADE WAY AND CONTRIBUTING OFF SITE CONDITIONS IS CRITICAL TO AVOID A REAL AND PRESENT DANGER TO THE HEALTH, WELFARE, AND SAFETY OF THE CITIZENS OF TUKWILA AND KING CO. ATTACHED IS AN INTERNAL MEMO FROM PHIL FRASER TO DARREN WILSON CITING THE SLADE WAY SLIPPAGE PROBLEM. 1 ALSO HAVE HAD DISCUSSIONS WITH RALPH HEITT AN INSPECTOR FOR ENTRANCO WHO HAS A CONTRACT WITH THE CITY OF TUKWILA TO SUPERVISE THE CONSTRUCTION OF KLICKITAT DRIVE & S. 160TH ST. MR. HEITT HAS INDICATED THAT SLADE WAY HAS REAL STABILITY PROBLEMS AND HAS SETTLED SOME TEN INCHES IN THE RECENT PAST. PLEASE LET ME KNOW WHAT IT I5 YOU WANT TO DO ON MY PROPERTY TO RESOLVE THIS PROBLEM. SINCERELY YOURS \ if LEROY C. LOWE A.I.A. A CHITR.CT - CC : MAYER, CITY COUNCIL TUKWILA BLDG. STAFF ADMINI`TRATIVE PLANNED RESIDENTIAL DEVELOPMENT APPLICATION CHECKLIST CITY OF TUKWILA DEPARTMENT OF COMMUNITY DEVELOPMENT n 7 I l 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431 -3680 The following materials must be submitted with your application. This checklist is to assist you in submitting a complete application. Please do not turn in your application until all items which apply to your proposal are attached to your application. If you have any questions, contact the Department of Community Development at 431 -3680. RETURN THIS CHECKLIST WITH YOUR APPLICATION GENERAL HILL Application Form Administrative PRD Application- Environmental Checklist Environmental Checklist Fee — $225 00 PLANS n Four copies of the set of plans are required. The scale shall not exceed 1 " =30', with the north arrow, graphic, scale and date all identified on the plans. The following information should be contained within the plan: n A. Property dimensions and names of adjacent roads. B. Lot sizes in square feet. n C. Impervious (paved driveways and building areas) surface areas, stated in square feet and as a percentage of each lot's area. n D. Existing and finished grades at 2' contours with the precise slope of any area in excess of 15%. IT E. Location and dimensions of existing and proposed structure(s), accessory structures and driveways with their setbacks from proposed property lines. n F. Existing (6" in diameter) trees by species and an indication of which will be saved. n G. Proposed landscaping, size, species, location and spacing, for dow•nslope and sideyard buffers for geologic hazard areas. ' A King County Assessor's Map which identifies the location of each property ownership and residence listed. The maps may be ordered from the King County Public Works Map Counter at 296 -6548. ,tidy se", PRELIMINARY GEOTECHNICAL INVESTIGATION FOR HILLCREST SLADE WAY, SOUTH OF SOUTH 160TH STREET TUKWILA, WASHINGTON JOB NO. 9005 -13G TABLE OF CONTENTS Scope Project Description Site Description Subsurface Soil Conditions Laboratory Results Conclusions Recommendations Foundation Design Parameters Drainage General Page 1 Page 2 Page 2 Page 4 Page 5 Page 6 Page 7 Page 8 Page 8 Page 9 Apppendix A Test Pit Locatin Map Appendix B Test Pit Logs Appendix C Unified Soils Classification System Appendix D Laboratory Results CASCADE GEOTECHNICAL, INC. 12911 N.E. 126TH PLACE (206) 821.5080 KIRKLAND, WASHINGTON 98034 FAX: (206) 823.2203 April 24, 991 Job No. 9005 -13G Leroy Lowe P.O. Box 1241 Seattle, Washington 98111 Reference: Plan Review Hillcrest Slade Way Tukwila, Washington Dear Mr. Lowe: As requested, we have prepared this letter to summarize our review of the information you provided and in our files. The purpose of our review is to comment on the items raised in the letter by Mr. Fraser of the City of Tukwila dated March 4, 1991. We have reviewed the undated Sheet #8 (Drainage site plan and site plan) and the unnumbered, undated Sheet "Grading site plan" of the plans prepared by Leroy Lowe Architect. We also reviewed Sheets #1 (Drainage site plan) and #3 (Grading site plan), and Sheets #1, #2 and #3 of undated sets of site plans prepared by Leroy Lowe Architect before the latest revisions were made. Our review also included our soils reports for this property dated May 30, 1990 and August 27, 1990. PROJECT DESCRIPTION We understand from our review of the revised plans provided that the proposed development will consist of three (3) single family residences with an access road from Slade Way serving Lots #3 and #4, and another access road from Slade Way serving Lot #5. The previous plans showed two additional houses at the top of the slope with an access road from Slade Way. The buildings on Lots #3, #4 and #5 will be located east of the toe of the thirty (30) foot high 2(H):1(V) slope. REVIEW No building plans were provided which showed the foundation details for the proposed buildings. We understand from conversations with you that the proposed residences will be supported on a pile foundation in accordance with the recommendations in our soils report. However, for us to adequately address the impact of the proposed construction on surrounding properties and the slope we CASCADE GEOTECHNICAL April 24, 1991 Mr. Leroy Lowe Job No. 9005 -13G Page 2 should review the final building plans in detail. We understand from Sheet #8 (Drainage site plan) that groups of six (6), two (2) inch diameter horizontal drains, separated from each other by ten (10) feet 0.C., will be installed along the toe of the existing slope, in areas where the slope is to be regraded. No specific details for these horizontal drains were provided on the plan we reviewed. These horizontal drains will exit into a north- easterly trending French Drain to the west and extend westwards approximately twenty (20) feet horizontally. We recommend that specific details for the horizontal drains be reviewed by us and incorporated into the final plans. We understand from the Drainage Site Plan that proposed French Drains will be a minimum of six (6) feet deep and two (2) feet wide. The French Drain detail provided on the plan shows visqueen lining across the bottom and along the downslope side of the French Drain trench, with electric, telephone, and cable lines located within the French Drain trench. In our soils report we recommended that the French Drain trench be lined with a permeable geotextile fabric to avoid future clogging from siltation. We recommend that this be included in your final plans for the uphill face not covered by visqueen liner. We recommend against placing any utilities within the French Drain trench, since access to the utilities would compromise the integrity of the French Drain. With the exception of the above stated discrepancies, we believe that the Drainage Site Plan reflects our recommendations. We understand from the Grading some parts of the toe of the show that the slope will be grade behind the southwestern #3. In our soils report dated against making any cuts into cuts steeper than a 2(H):1(V) retaining wall. Site Plan that you propose regrading existing slope. The grading plans regraded at 1.5(H):1(V) or steeper corner of the house proposed on Lot August 27th, 1990 we had recommended the toe of the slope, and that all grade be supported with a structural We understand from conversations with you that you anticipate placing a four (4) foot high retaining wall in the area of the steep cuts. We recommend that we be engaged to calculate the lateral forces for the retaining wall and review the retaining wall design. The houses proposed on Lots #3, #4 and #5 appear buildable, provided the recommendations in our soils reports and this review are followed carefully, and adequate drainage of the site is CASCADE GEOTECHNICAL April 24, 1991 Mr. Leroy Lowe Job No. 9005 -13G Page 3 accomplished prior to the initiation of proposed construction. To fully answer the City of Tukwila's questions, more specific and detailed plans will be necessary. A slope stability analysis, with static and pseudostatic impacts of the proposed construction will be required. We recommend that we be engaged to conduct a slope stability analysis for before, during and after construction scenarios to evaluate the possible adverse impacts of the proposed construction on the existing slope conditions. This will require more specific information on the building loads and foundation type. A slope stability analysis beyond the level we have completed is inappropriate at this time. We feel that adverse effects of the proposed development have been lessened by eliminating the houses on Lots 11 and #2 and the construction of the driveway on the face of the steep slope. We will conduct a slope stability analysis based on the final plans at the time of permit application. The site is located above a known area of instability with a recent history of slope failure. It is our conclusion that the Hillcrest site is presently stable. The proposed construction should not adversely effect Slade Way if our recommendations are carefully followed. Careful construction techniques and drainage control will be necessary to avoid any adverse effects of the proposed development. As indicated previously, the site may be seriously affected by off -site events or development. The site lies within Zone 3 of the USGS Classification of Seismic Hazard Areas. Based on our understanding of the present soil and physiographic conditions present at the site, we conclude that the proposed buildings will require deep seated foundations to achieve the acceptable levels of safety. We recommend that we be engaged to review and provide specific and detailed recommendations once detailed plans are available. Thank you for this opportunity to be of service. Please contact us if you have any questions or require further assistance. Sincerely, CASCADE GEOTECHNICAL: °'eG;: E, a:, (.),. :tip ( t 1 stro Amjad I. Khan Geologist ADMINIST ATIVE PLANNED RESIDENTIAL DEVELOPMENT APPLICATION ;ITY OF TUKWILA EPARTMENT OF COMMUNITY DEVELOPMENT 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431 -3680 FOR STAFF USE ONLY Planner: File Number: Cross - Reference Files: Receipt Number: 1. TOTAL NUMBER OF PROPOSED DWELLING UNIT LOTS: 5 ( iv.=) 2. ZONING OF SUBJECT SITE: /O.0 3. PROJECT LOCATION: (Give street address or, if vacant, indicate lot(s), block, and sub- division; or tax lot number, access street, and nearest intersection) '',29, 24 27, Za., z6 , S!lG 7*S,7 5e4 Z rs OZ2lo, D23o, 0224, OZZ0, oz/5- Quarter: MW Section: 2la Township: Z3 Range. 4 (This information may be found on your tax statement) 4. APPLICANT:* Name: Address: Po, 80X 397 2 Phone C 7 454 44 Si natur fe -- C'. Date. S, /79/ * The appli ant,fs the person }whom the staff will contact regarding the application, and to whom all fiotices and ieports shall be sent, unless otherwise stipulated by applicant. C. Za we. 4, /. 4, ,12c,4/77_C7 255GL5 yc% WA. 98009' r D6) 747- .'4 70 5. PROPERTY OWNER AFFIDAVIT OF OWNERSHIP Name: !c-E oy C. Zo v ,r# , /,,4 • ,4nG,41/ T :GT Address: Pep , aBoX 7 Z l' Ph 464 - -4 4Z3 (:7;o6) 747. ?470 I /WE,[signature(s)] swear that to are in this application an application are true a er(s) or contra purchaser(s) of the property involved that the foregoing st tements and answers contained in this d correct to the of my /our knowledge and belief. Date: PT. 3 , / 9 9/ IiILLClZ6T CITY OF TU W DEPARTMENT OF COMMUNITY DEVELOPMENT ADMINISTRATIVE PLANNED RESIDENTIAL DEVELOPMENT INFORMATION 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431 -3680 The Planned Residential Development (PRD) process, by permitting flexibility in zoning code requirements, encourages imaginative site and building design, accommodates environmentally sensitive areas and creates open space in residential developments . The number of dwelling units is determined by the underlying zoning district, and minimum lot sizes, building height limits and setbacks are waived. A density bonus of 20% may be allowed in R -2, R -3, R -4 and RMH, subject to adherence to the bonus criteria. The area encompassing the sensitive area and buffers must be devoted to open space that is owned and maintained under one ownership, by a homeowners association or dedicated to the City (if adjacent to a City trail or park). If you are platting property with sensitive areas or sensitive area buffers, you must submit a PRD. CRITERIA The Short Subdivision Committee's decision shall include the following findings: 1. Requirements of the subdivision code for the proposed development have been met, if appropriate; 2. Reasons for density bonuses meet the bonus criteria; 3. Adverse environmental impacts have been mitigated; 4. Compliance of the proposal to PRD and sensitive area requirements; 5. Time limitations, if any, for the entire development and specified stages have been documented in the application; 6. Development in accordance with the comprehensive land use policy plan and other relevant plans; 7. Compliance with the BAR review guidelines (TMC 18.60.050); and 8. Appropriate retention and preservation of existing trees and vegetation recom- mended by the Director of Community Development. PROCEDURE A Short Subdivision Committee meeting will be scheduled when an environmental determination has been made on your application. Notification of the meeting will be sent to all property owners within 300 feet of the subject site. tii:vw:.S �ar:rtwl >Y�ar iwaar�;;v)o'�ii:C:o3 CITY OF TUKWILA DEPARTMENT OF COMMUNITY DEVELOPMENT Single Family Residential Environmental Checklist When a Checklist is Required: Property owners who wish to develop or remodel a home on a parcel mapped as a sensitive area must complete and submit an environmental checklist. Sensitive areas are lands which slope 15% or more, have a watercourse or wetland on them or are in a coal mine or seismic hazard area. Maps have been made of all of these areas by the City, with the best available information, and are available for your review. Purpose of Checklist: The State Environmental Policy Act (SEPA), chapter 43.21C RCW, requires Tukwila to consider the environmental impacts of your proposal before making decisions. The purpose of this checklist is to provide information to help you and Tukwila identify impacts from your proposal and to reduce or avoid those impacts. Instruction for Applicants: A determination of nonsignificance must be made by the Director of Community Development before you may apply for a building or land altering permit. A fee of $225.00, a completed environmental checklist and a site plan, and any additional information that will help describe your proposal or its environmental effects, must be submitted to the Department of Community Development in order for the determination to be made. This environmental checklist asks you to describe some basic information about your proposal. Answer each question briefly, accurately, with the most precise information known, or give the best description you can to the best of your knowledge. In most cases, you should be able to answer the questions from your own observations or project plans, without the need to hire experts. If you really do not know the answer, or if a question does not apply to your proposal, write "do not know" or "does not apply ". Complete answers to the questions now may avoid unnecessary delays later. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels of land. DE TERMINATION OF niLCCr�sT 1. Description of proposal: 'M 4 y /'vE 14- T7%-'7.5%vT QoouG AT /dAl 2. Name of applicant: L.e'c©y Vv' . ,4. Acc,4{/7"-N 3. Location of site (use address, lot & block number, and tax account number(s) if ap licable): i'o�'7jc^iS oP Lc75: 7, Z. C7, 5 @ S /Ga 's'57; SL OE WA>/ 74x LOTS ,,OZZG, DZZ4, 0220, Oz /6'. For completion by staff Lead Agency: City of Tukwila File No. EPIC The City has determined that the proposal will not have a probable significant adverse impact on the environment. An environmental impact statement (EIS) is not required under RCW 43.21C.030(2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. This information is available to the public on request. O The decision was also made because of specific conditions attached to the proposal. O This DNS is issued under WAC 197 -11- 340(2). Comments must be submitted by The City will not act on this proposal for 15 days from the date below. L. Rick Beeler, Responsible Official Director, Department of Community Development, 431- 3681 6300 Southcenter Blvd., Suite. 100, Tukwila, WA 98166 Date, Signature »; . You may appeal this determination to the City Clerk at City Hall, 6200 Southcenter Boulevard, Tukwila, WA 98188, no later than 10 days from the above date by written'.: appeal stating the basis of the appeal for specific factual objections. You may be required to bear some of the expenses for an appeal. Copies of the procedures for SEPA appeals are available from the City Clerk and Department of Community Development. Give brief, complete description of your proposal: Site size: /07, 9'8 0 T House size: N. d Accessory structures: Al, 4 Proposed uses: AglM/Ly LcTs ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site (circle one): Flat, rolling, hilly, steep slopes, other: CO■e/A.47 7ON c.",=• b. What is the steepest slope on the site (approximate percent slope)? 39 %o c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, muck)? If you know the classification of agricultural soils, specify them and note any prime farmland. _ rev= L5c5 Tb cov e6 S4A S d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. 44".S./' c• s 4'.ay. OCCC./R.,1".:C> To 7716 ..1"445 T .44■'oSS S44'E wAy • 1 HALO Ze_51- e. Describe the purpose, type, and approximate quantities of any filling or grading proposed: Z/00 Ca. GT. PE../Z. 1.c) 7 fd2 F?ENC,g, Ane..4 /N. Where is the source of fill obtained: Roe.< 4kcaeey 1 G2A ✓EL 0/7- . f. Could erosion occur as a result f clearing, construction, or use? If so, generally describe. /V/4 ff=ae ecxd∎v y L/Ne �O ✓• Soi' i Ereasio i /-1,4 y GYGU,e O[1R /NG G„2.bd ///G NS Z./A1/ TE17 TD A::',SC /oz, od L0Ry Wed %e g. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: /NSTGLL S/ -7 4T /Cav $4S /Ars 4).e4 hv.4rg.0 Vat. o/ss /vases, ,2e•P/..p,vT, 7 47, ifs /�v C�vT.�oL 6-77tt.G, 4eLS h. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? N/14 1^YG f'V L/A(E <1c ✓u5?` ^ =n�T �ovG/c� Tio,V oNL y . 2. Water a. Surface: 1) Is there any surface water on or in the immediate vicinity of the site (including year -round and seasonal watercourses, ponds, wetlands)? If yes, describe the nature of the water. If appropriate, state what stream or river it flows into. S /r. jcbT 1J57 a GIN 7Z/KI4Y /Z. W�77_/ O /N1//y7, 2) Will the project require any work over, in, or adjacent to (within 200 feet) the described water? If yes, please describe and attach available plans. N/4 44ek, un/, ,e"/ b1/41Z .4G - - 57 t-ICA r ,='U G.S 77 0 Al 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material: Z5' C•f-. p ��- ,�c�c.� cp 447,eQ ' � G4,4 v� G pi r 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities, if known. Ye S" . 1 C4 /n/ vc,//LL SeP*4 G6 ANC, ,Ozee'G:T ,=Lctiv /Nro GrX /c�ST /NG STo/'ic-J 1:)/24)9.1 5) Does th - • roposal lie within a 100 -year floodplain? crier If so, note location on your site plan. 2 nrLccIZeST 6) Does the proposal involve any discharges of waste materials to surface waters? 11 so, describe the type of waste and anticipated volume of dischar e. No N/A Bou/vc y L. /NC Ac it'srfrie.vr ,los=t /c47io/v scvvt..y b. Ground: 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities, if known. F,2✓vGl ,p,QA /N 1, i /cam r- 'C '7 G,2o /rvc v 4TEK ,4N0 ,C)/VAT /N 7b EX/STih/G D2</N. 2) Describe waste materials that will be discharged into the ground from septic tanks or other sources. Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve._ No D /sC .za ,4Ny ?"f/ /^/ eouiv0,4¢y L /SIC Aac../IJS 7-MCA/ T 4,..:=1.!.../C4 Ti cA/ oNL , c. Water Runoff (including storm water): 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, , if known). S5,4'04GE o"/ 5o2/tiG 5 coLG6G7o ,may .Q 4/ev ,441/4/o //1/4/7b Where will this water flow? x /STiyG .572: )0 G32.�4 /N Will this water flow into other waters? C)AN-Y ,:15 May ,& ,Gw2 SGT:= L� c)/ X/. 7 1 If so, describe. Gam• -/A/1 ys % M 2) Could waste materials entey ground or surface waters? If so, generally describe. /i/ /A ,43=2zJs/4).4 y L/A/C r4oJ T'- 'T 4'4' c.477 o /L d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any: .,2E/v ,Sy S -7-e"..1 W /LL CoL LL"G? G.Ccx./ v.0 wy1T5,z £i /2Z,C w i/ / TT", X /.5 7-/A/G 572YzA9 ,C4 /N. Sedig,=.4cc VV47 , ' ,4:72ESzi.c/vTz.y /S rrn(1,�rr2 ey A Q<•N t57 EL GyL'6GT�..D /A(7-Gs -4A/ �X //ST /Ak. 57 ,C» 1 �T wF,e, Cy'$7'E VJG STAMEN •••••fr A BRISTLE C's SCALE SPIKE-RUSH These annual or perennial grass.lilie herbs have round to flattened stems and tend to grow In clumps in areas with wet soli. FLOWER CLUSTER To.1) BRACT.** A TRIANGULAR STEMS SHEATHING LEAF BASE IF**.FLOWER CLUSTER XX. SEDGES klants other: WES it'. CONE NEEDLE NEEDLES OF VARYING LENGTHS 2-WMITE STRIPES WESTERN HEMLOCK A forest • evergreen of up to 60-70m 060-2001 high. Western Hemlock 55•s distinctively drooping branches and tips, and strongly furrowed dark to red• dish•brown bark. Under certain conditions It may be Sound with Western Red Cedar in very old stands with little growing beneath the trams. 0 shrubs: wiliew, saimerrirerry, Ineliere-pittrn, other: BLAGX ,13,y PURPLE FLOWER ORANGE-RED BERRIES f"-THORNY ..STEMS SALMONBERRY FUZZY NEW LEAVES-- STIPULES LOST ON OLDER GROWTH LATERAL BUD / WILLOW This deciduous tree or shrub Is Olen Sound growing with Red Alders along the The tangles of curving, thorny stems formed by this perennial shrub provide i• difficult to Identify willows to shelter for nesting virds and small rodents. It is found growing 1.4m (3.12') O pasture E) crop or grain o wet soil plants: 6.1,444-* , lytrtterettp,1,1±14rtrshLskunk cabbage, other Emergent Plants — MALE FLOWERS SIFEMALE FLOWER SHEATHING LEAF_BASEG - CATTAIL The classic plants associated with marshy areas, Cattails, form large, almost pure strands 1.3m (3.11) tall In shallow • quiet water. They provide cover and nesting are•• for many birds. and • food source for many animals. The roots, stern pass, and wt.), young flower stalks are edible. Emergent Plants 1-1 water plants: water lily, eeires, ''other Ane.t.le 7-4/(-5 BRACT • 4.1) WHITE FLOWER,,, • - 04. Ow. • •.,4••••l, s::71..,1447.7" BRACT..c.' r. 1 l'IN's .. 1 • .1 ,.... "-•"'' ' ••' '‘V... n . : "=". ••• ..,.../",' , t• . ;11.,,.. .." •.1, 1......S. ':' • / "..›. PURPLE RIBBED STEMS ..\1•4.'.1 47.2.:;j1 ;• I. - . %.,. :LC WATER PARSLEY Other types of vegetation Please list /vy icy5 s Z.),41s/eLic:vc./ FP A o•-- Ae-1:=,1/4/ NoNC d. What is the current zoning classification of the site? A"-/-/2..0 R tlILLCI2Cc5T e. What is the current comprehensive plan designation of the site? ,,5/NL6 ,,.a/.-7/e... V /e /,OE../vcr.4 L f. If applicable, what is the current shoreline master program designation of the site? Urban N/A Has any part of the site been classified as an "environmentally sensitive' area? If so, specify. )/e`.5 , s7m,47. sLr_p6 g. 6. Aesthetics a. What is the tallest height of any proposed structure(s), not including antennas? N/4 B.oz..bvo y �a�Jv5TM6N/7 f4P. .../G1L7/0A, vAILy b. What views in the immediate vicinity would be altered or obstructed? N/A c. Proposed measures to reduce or control aesthetic impacts, if any: N/A 7. Utilities a. Circle . 'liti - ntl ' av -' -. e at the situ -fit+ IMt efuse s rvice tele • hon - anita ewe • sere system, other: .$7 iil SS vvzAw 4y5 TEfrl G484.C. 7 V. Pl1,3G,iC 7X"..4iv5 T.4-Ti(="✓ b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed._ N /4. 450e -riv y L✓.v6 .4�JGlu >.�E�/ T �o�v�► �o� oNz-y. A- .e.e,MpA.. y�/s/ su ,Z57 :, F) Tv2� UT /G,/ 77"/..T Although the following are important elements of the environment, most individual single family construction projects will not have a measurable effect on them. If impacts are anticipated due to your project, please indicate where appropriate. Complete the checklist by continuing with Number 17. 8. Air a. What types of emissions to the air would result from the proposal (i.e., dust, automobile odors, industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known. N/A b. Are there any off -site sources of emissions or odor that may affect your proposal? If so, generally describe. N/A c. Proposed measures to reduce or control emissions or other impacts to air, if any: N/A 9 /i /GGC!ZeST 9. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. N/A b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. N/A c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: N/A 10. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. N/A 1) Describe special emergency services that might be required. N/A 2) Proposed measures to reduce or control environmental health hazards, if any: N/A 11. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low- income housing? One 6' 7,5 M/dOG,e /n/eoML b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low- income housing. N/A c. Proposed measures to reduce or control housing impacts, if any: None 12. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? N/A b. Could light or glare from the finished project be a safety hazard or interfere with views? N/A c. What existing off -site sources of light or glare may affect your proposal? N/A d. Proposed measures to reduce or control light and glare impacts, if any: N/A 13. Recreation a. What designed and informal recreational opportunities are in the immediate vicinity? N/A b. Would the proposed project displace any existing recreational uses? if so, describe. N/A c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: N/A .ln nILLCI.�E6T 14. Historic and Cultural Preservation a. Arc there any places or objects listed on, or proposed for, national, state, or local preservation registers known to be on or next to the site? If so, generally describe. N/A b. Generally describe any Landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. N/A c. Proposed measures to reduce or control impacts, if any: N/A 15. Transportation a. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. N/A b. Is the site currently served by public transit? if not, what is the approximate distance to the nearest transit stop? N/A c. How many parking spaces %%'ould the completed project have? How many would the project eliminate? N/A d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). N/A e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. N/A f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. N/A g. Proposed measures to reduce or control transportation impacts, if any: NIA 16. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally describe. N/A b. Proposed measures to reduce or control direct impacts on public services, if any. N/A 17. Signature The above answers are true and complete to the best of my knowledge. I understa that the Lead agency is relying on them to make its decision. r Signature: ' Date Submitted: �_)c.r6P7." /Gla /99/ 11 HILL CQECST LEROY C. LOWE A.I.A. ARCHITECT P.O. BOX 1241 SEATTLE. WASHINGTON 915111 Lqc-, WETLANDS STUDY CITY OF TUKWILA HILLCREST LEROY C. LOWE, A.I.A. ARCHITECT 410 BELLEVUE WAY S.E. BELLEVUE, WASHINGTON 98004 454 -4423 SITE LOCATION: SLADE WAY AND SOUTH 160TH STREET TUKWILA, WASHINGTON MINER] PREPARED BY: APR 201992 BREDBERG AND ASSOCIATES, INC. POST OFFICE BOX 1337 CITY OF '1 UKWILA GIG HARBOR, WASHINGTON 98335 (206)858 -7055 JOB#1112 APRIL 16, 1992 PLANNING DEPT. TABLE OF CONTENTS PAGE INTRODUCTION 1 SITE DESCRIPTION 1 METHODOLOGY 4 WETLAND A VEGETATIO N 5 SOILS 5 HYDROLOGY 6 WILDLIFE 6 VALUES & FUNCTIONS 7 WETLAND B VEGETATION 10 SOILS 10 HYDROLOGY 11 WILDLIFE 11 VALUES & FUNCTIONS 11 WETLAND C VEGETATION 10 SOILS 10 HYDROLOGY 11 WILDLIFE 11 VALUES & FUNCTIONS 11 UPLANDS 12 IMPACTS 15 RECOMMENDATIONS 16 TABLE OF CONTENTS, CON'T. FIGURE 1: VICINITY MAP FIGURE 2: WETLAND LOCATION & TOPOGRAPHY MAP FIGURE 3: WETLAND AREAS FIGURE 4: CITY OF TUKWILA,WETLAND MAP FIGURE 5: KING COUNTY SOIL SURVEY APPENDIX A: TUKWILA WETLAND RATING FORMS APPENDIX B: TUKWILA WETLAND DATA FORMS TABLE 1: VEGETATION LIST • TUKWILA WETLAND REPORT HILLCREST The following report is prepared in an objective manner to describe the wetland and its values and functions. The wetland report follows the format as shown in the outline and discusses the values and functions according the wetland rating field form for the City of Tukwila (Appendix A). SITE DESCRIPTION The site consists of lots 25 through 29 on South 160th Street and Slade Way, tax lots #0226, #0230, #0224, #0220, and #0215. The site is located in the northwest quarter of Section 26, T23N, R4W. The property owner is Leroy C. Lowe, 410 Bellevue Way SE, Bellevue, Washington 98004. The subject parcel consists of 53,830.8 square feet in the subject parcel, and 10,176 square feet in a separate tract to the .south and east. The project consists of 5 separate tax parcels, with residences to the south of the parcel. The entire parcel is surrounded by either streets or single family residence lots. The parcel is bordered on the east by Slade Way and separated from Slade Way by a deep man -made ditch. There is a single family residence lot cut out of the northeast corner of the parcel, which is mowed and maintained with a fence around the perimeter. Additional homes are located to the northwest of the parcel and to the west across the level. Along the southern edge of the parcel is a 10 foot sewer easement. The topography is level to steeply sloping. The far western edge of the property is the highest elevation and is level uplands. Moving eastward, a steep slope drops down to the major portion of the site that includes the wetlands. The parcel slopes from the highest points at the western property boundary, east to Slade Way and northeast to 160th Street. The parcel shows evidence of considerable site disturbance. It appears that the site was used as a borrow pit at one time, as the site is terraced and the soil shows signs of excavation and re- grading. The dense tree and shrub growth indicate that excavation occurred several decades ago. Within the past few years there has been some grading and, most recently, clearing to facilitate placement of the test well. The site contains evidence of man's recent activities. Garbage cans and other assorted debris are present throughout the site. The ditch along Slade Way takes drainage from the lower portion of the site. Several footpaths are present throughout the site. A test well is located in the southern portion of the site. Two culverts are present on the woods road. Lawn and fruit tree encroach at the northeast corner of the property. A 40" Maple tree is just west of the lawn and fruit trees on a large mound of earth with signs of excavation around it. A culvert has also been placed at Wetland Flag #A to pipe the water to the roadside ditch. The northwest corner of the site also has evidence of landscaped encroachment. 2 The dominant feature of the site is the steep and relatively unstable bank of soil bisecting the property from north to south. The instability of the slope is evident as tree roots and bare soil have slid down the steep slope. It is this consultant's opinion that the site was a borrow pit to provide sand for construction at some time in the past. As the pit was abandoned, the steep slopes /vertical faces of the cuts lost their stability. The comments in this report on the slope stability are based on the surface layers of the soil and no inferences or recommendations as to slope stability with regard to geotechnical or foundations are made. SOILS: The following sections on wetlands and uplands give general descriptions of the soils within each. The site, especially in the area of the proposed development at the base of the slope, presents a complex soil situation. There are small areas of peat up to 3 -1/2 feet deep and within 25 feet there are sandy areas with no peat. The geotechnical soil logs describe a mixture of black to tan fine grained organic silty sand to depths of 5 feet. The description indicates that the site was likely a borrow pit. Deep organic deposits probably occur where the top soil and other organics have been placed and localized. The mixture of the silty sand and organics is likely to be where the bank has sloughed off and where machinery, as long as several decades ago, mixed the organics with the sandy material. At this time the definitive description of the soils can do little more than identify the site as a disturbed area with several seeps. The depth of the organic matter is not necessarily an indicator of the permanence or duration of the wetness. 3 METHODOLOGY The site was evaluated using the Federal Manual for Delineation of Jurisdictional Wetlands(1989). The routine methodology and data forms are provided in Appendix B. The Soil Survey, King County Area of Washington (1973), was utilized to make a general soil determination. A Registered Professional Soil Scientist prepared the section on soils. The wetlands were flagged and sequentially numbered and located by survey (Figure 2) Survey Professionals of 21436 SE 266nd Street, Maple Valley, Washington 98038, (206)251- 0189, performed a professional survey in locating the wetland flags. Additional information used in preparing the report include the geotechnical studies prepared by Cascade Geotechnical, Inc. of 12919 NE 126th Place, Kirkland, Washington 98034, (206)821 -5080. WETLANDS WETLAND A: Wetland A is the largest wetland on the parcel and covers 11,647 square feet. The wetland is vegetated by Scrub /Shrub vegetation with an overhang of trees growing in the uplands. Figure 2 shows the flag locations and the wetland configuration. 4 VEGETATION: Wetland A is dominated by emergent vegetation. Five Alder trees are growing in the vicinity of wetland Flags 1 through 3. The overstory of the trees growing in the wetlands is less than 25% for the entire wetland. Please note that the tree species as shown on the Wetland Survey Plan were located and identified by the surveyor. Some of the Red Alder trees are listed as Hemlocks. Table 1 lists the dominant vegetation present in Wetland A and in the uplands, respectively. The dominant vegetation in the wetland consists of a Scrub /Shrub layer of Salmonberry with an overstory of Himalayan Blackberry rooted in the uplands. Stinging Nettle and Skunk Cabbage are plentiful in the wetter areas, as are grass species and Water Parsley. SOILS: The soils of Wetland A are dominated by an organic layer over a B horizon of gray sand. The organic layer varies from 2 inches to up to 14 inches thick. The muck areas appear to be accumulations of top soil and organic matter that have eroded in the adjoining areas as the slope has broken off. Other areas of deep organics and mucks, appear to be a result of deposition by the placement of rotting leaves or the movement of soil with equipment. The wetland soils are classified as a Norma series when the organic layer is less than 6 inches thick. The Norma series is a poorly drained soil on the hydric soils list. Where the organic layer is greater than 6 inches thick the soils are poorly drained and of the Dupont Muck series. HYDROLOGY: The hydrology of wetland A is dominated by the seeps coming from the hillside to the west. Four main seep areas are located in the vicinity of Flag #39, 44 and 56. The seeps support the hydrology as they have running water throughout much of the year. In the dry times of the summer the seep may stop running. The water seeps out of the hills to the west, flows through the site and into the roadside ditch along Slade Way. One culvert and several seeps transport the water from Wetland A into the roadside ditch. Two culverts are present on the site allowing the woods roads to access the site and the test well. WILDLIFE: The wetlands offer a diverse habitat for wildlife. Primary wildlife present on the site were songbirds. No sign of other mammals or large birds was noted. The trees in the uplands around the wetland offer nesting habitat, while the wetland themselves provide food and water source for the wildlife. The major function of 6 the wetlands are the seeps providing surface water for wildlife. The greatest encroachment and the lack reason these wildlife. factor affecting this wetland is the urban around the outside edge of the wetlands of a corridor for wildlife. For this wetlands have a limited value for VALUES AND FUNCTIONS: Food Chain Support: Wetland A is given a high rating for food chain support as wetland is covered with emergent Cabbage, Water Parsley, Stinging species support the food chain. 75 to 100% of the vegetation. Skunk Nettle and grassy Nutrient Transport: This wetland is given a moderate rating for nutrient transport as there is a seasonal stream leaving the wetland. The wetland is not given a high rating as the discharge from the wetland is collected in the roadside ditch and is transported into the storm sewer system at 160th Street and Slade Way. Buffer /Barrier Function: The wetland is given a low score for this function. Much of the area around the wetland has been disturbed and is either part of Slade Way, maintained lawn, or vegetated with invasive species such as Himalayan Blackberry. Much of the western portion of the wetlands buffer is part of the unstable slope that sloughs off, providing little protection for wildlife. Prime consideration in providing the low score for the buffer function is the relative ease with which people have access to the wetland. Several paths enter the site. A road bisects the property that permits access to the test well and Slade Way has little buffer between the wetlands and Slade Way. Habitat: The wetland has 2 classes of wetlands without open water. The scrub shrub and emergent wetland class. Less than 20% of the wetland is forested, therefore, it is not given a forested class. The size of the wetland is 11,640 square feet, is less than 1 acre, therefore it is small and low in value. Forested Wetlands: The site is less than 30% forested wetland, therefore, is given a low value in this function. There is forest around the wetlands, but these consist of primarily of big leaf maple and alder trees growing in the uplands. As the wetland has less than 30% aerial coverage by trees, it is classified as a Scrub /Shrub wetland (Classification of Wetlands and Deep Water Habitats of the United States, 1979. Cowardin) Habitat Buffer: The habitat buffer is diverse in that it encompasses a forested urban and scrub shrub areas. Approximately 10 to 25 percent of the area is a diverse forest or scrub shrub, while 25 to 50 percent is open forest with grass and occasional shrubbery. Approximately 50 % of the buffer is given a pasture or herbaceous category as the buffer includes Slade Way and several lawns. 8 . WATER QUALITY: Residence Time: The residence time of water in the wetland is short as it is a small wetland on a relatively steep slope for a wetland. A value of one is given for this score due to the small size and lack of residence time. Vegetation Density: Vegetation Density is approximately 70 to 100% coverage of the wetland with emergent vegetation, therefore, there is a high score for this value. Referring to Appendix A containing the data sheets for wetland A, the total score for the wetland is 20. WETLANDS B AND C: VEGETATION: The vegetation of wetlands B and C is similar and consists primarily of stinging nettle, skunk cabbage, and grass species. The wetlands are small and have an overhang of Salmon Berry and Himalayan Blackberry rooted in the uplands. SOILS: The soils of wetland B and C are similar in that they are on the unstable steep slope. The soils consist of a gray loamy sand to sand, with an organic surface 2 to 10 inches in thickness . The soils are classified as belonging to the Norma series, except where the organic 10 VALUES AND FUNCTIONS: Values and functions of wetland B and C follow the analysis on the wetland rating field form for wetlands B and C in Appendix A. The two wetlands are located adjacent to each other and are similar in their wetland rating. Food Chain Support: The wetlands have a 50% cover of emergent vegetation are given a moderate score. Nutrient Transport: These wetlands are isolated closed depressions and receive a low score. Buffer: The buffer around these wetlands is not effective in reducing human encroachment. There are 11 1,14 'SAN footpaths adjacent to the wetlands, and garbage cans and other debris within the wetlands, showing that the buffer is no working. The test well is located between the two wetlands and it is possible that the drilling of the test well has created some of the wetlands. For this reason the level of human encroachment is very high, therefore, the buffer functions is low. Habitat: The wetlands have 2 wetland classes without open water,as emergent vegetation with some Salmon Berry are present. SIZE OF WETLAND: Wetland B is 518 square feet and wetland C is 1,011 square feet. Both wetlands receive a low score for wetland size. Percentage of Forested Wetland: Neither wetland is forested and is given a low score. Buffer Habitat: Between 10 and 25% of the habitat within 100 feet is a diverse forested shrub, while 25 to 50% is open forest with grass and 50 to 75% is pasture, herbaceous. The pasture, herbaceous is based on the close proximity of the grassed lawns to the wetland. Surrounding Land Use: The surrounding land use is urban residential and this provides a negative land value. Unique Features: There are no unique features in either wetland B or C. Presence of Water: There is the presence of water in these two wetlands is intermittent even during the wet times of the year. On this basis it is given a low rating. WATER STORAGE FUNCTIONS: Location of Water Shed: As these are isolated wetlands they are given an upper third or two score in the water storage function. Storage: The wetlands are small, less than 1 acre and are given a low value for this function. WATER QUALITY: Residence Time: The low flow into these wetlands and lack of any surface water provides for a low value for this function. Vegetation Density: These wetlands are given a moderate value for vegetation density as they are 50 to 75% emergent vegetation. The total score for the wetland rating field form for the City of Tukwila is 14 based on the totals of the three sheets. UPLANDS: The uplands of the property dominate the site and are present in three separate plant communities. The western upper levels of the parcel are a mixed forest of Big Leaf Maple and Red Alder, and an understory of Salmon Berry is present. Table 1 lists the dominant vegetation in the uplands. The second of the three upland vegetation communities consists of the steep slope breaking from the higher elevations to the lower elevations. The steep slope is vegetated with Red Alder and Big Leaf Maple trees and has an under story of Salmon Berry. The slope is breaking off and eroding down to the lower levels, with bare areas. The third community of the upland area consists of the lower elevation site around the wetland areas. This upland area consists of a transition community from the upland to the wetland species. Some of the higher organic matter upland areas contain some wetland vegetation that are remnants of the wetland plant community prior to the site disturbance or erosion. The upland tends to lack the wetland hydrology due to the landscape position. The vegetation surrounding the wetland areas has an overstory of Red Alder, Big Leaf Maple and an understory of Red Elderberry, Himalayan Blackberry, and Vine Maple. SOILS: The soil survey of King County lists the entire area as of the Alderwood series. An on -site inspection by a Registered Professional Soil Scientist determined that the area is not of the Alderwood series, but an inclusion of Indianola into the Alderwood map unit. Indianola soils range from loamy sand to sand; this explains why this site was probably used as a borrow 14 pit. Indianola soils, if they are of good sand quality, are useful as construction material. Once the site was used as a barrow pit, vertical slopes were left and the Indianola soils tend to erode down the steep slopes. Indianola soils are well drained soils, and not on the hydric soils list. IMPACTS: The proposed use of the site is to construct five single family residences. Presently the residences are to be constructed, four along Slade Way, and one house having access off South 160th Street. Several factors need to be taken into account in assessing the potential impacts of development . The proposed construction of houses, regardless of location, will require the filling of some of the wetlands. Houses constructed in the western uplands will need an access road, which will impact the wetlands. Furthermore, the geotechnical reports recommend dewatering the hillside to maintain slope stability for the houses and the roads. The dewatering will likely drain the wetlands. Geotechnical reports reference slope stability and slides in the area are documented by Dames and Moore in 1961. Dewatering of this site may be required regardless of house construction. 15 ■.< RECOMMENDATIONS: The following recommendation s are offered as an alternative that will allow construction of the five . and functions. of the wetland area. It is understood that the wetlands will be impacted but the enhancement recommendationbs should stabalize the area and provide for the long term wildlife habitat potential of the site. The main function of the wetlands is for song birds, recreation and supplying surface water. Dewatering of the area and construction of the houses could be performed with no significant loss in these functions. The construction of a small open water pond fed by water from the dewatering system or the municipal supply would provide perennial water for wildlife. Dewatering would pipe the groundwater directly to the storm sewer. The water source for downstream water quality would be unimpacted. There would be a loss in food production from the wetland, but the small size of the wetlands provides minimal food production. Enhancement plantings could be made to provide habitat. The invasive non - native species, Himalayan Blackberry, would be removed. The present hydric soils, especially the organic, would support a wide variety of vegetation including the present wetland plants. Over time, the obligate wetland species would be replaced by facultative species. The facultative species would be planted as 16 part of the enhancement planting and provide a greater source of food than is present today. The present situation has invasive species taking over the site. Human intrusion, garbage and debris are common, and much of the wetlands are disturbed by the woods road. The overall habitat could be improved through an enhancement plan. It is recommended that the house sites be located along Slade Way and 160th St. to minimize the impact to the wetlands. A conceptual enhancement /mitigation plan will provide for plantings and a perennial surface water supply. 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S7- FD 1/2 "RB /CAP LS{/ 6012 Pe fpE' 41�q 0.17N X 0,06W re..,e p�P /2. i1 'mot �2$i �es.•7 " HEMLOCIZ to I3 0 HEMLOC .- 0 CS;. rn • • ip 0 0 In • 30'w HEMLOCK 20" IIEMLOCK 1 / FD 1/ : Rp /CAP LS. 602 0.26N 0.4 j ! - - IAWN & FRUIT 1REE i1 / •\ ENCROACHMENT 0" 'HEMLOCK 24" ':11EMLOCK 0) c1- 00 330.0 40" MAPLE WL WL25 C UMP .2 16 7, L1- k18 7" MAPLE i ° 30" MAPLE 1 V" 11EMLOCK 20" CEDAR 15 �� L63L 0 - 4' WIRE ELME 4.0' 11. 22" MAPLE WL71 jWL'70 W1)9 I� LAJ Q MH 26 -18 RIM EL. 248.60 PIPE 8' STEEL H PIPE 8' STEEL TEEL S A f � 240.78 R�g55.62' 1,41.19 I�' l ^265'51 B' 3 1'1 q.3 1 1 P LE. 240.55 240.75 240.72 ki" MAPLE 14" FIR 6-1<Thia ') 20" b APLE +ut FOU+ 15" I,IEML K MW 26- 9 . RIM EL. ?91.10 PIPE O'S1EEL 11 PIPE 9' STEEL S PIPE. O'S1LLL•, D M • 248.1 40.0 8.2 '• • BC IN FEEL PIPE 2 23 1:: 1 !7 26 7.• 1L.1 p . 0 • 0 OZ • LANDSCAPED ENCROACHMENT • ' s88'./03'22" • 140.00' 20" .1 iEMLOCK SIIE8 0.7;'• FENC ..„._ .ENCROACHMENT . . 4 Id to r:0 0. P4.) to •.. • L37 " 1-1E.MLOC1 ..• 20" HEMLOC\ \ 30' HEMLOCK • • FD /2"RB/CAP LS# 6012 et OSA 0.17N X 0.06W pi • pee, , ees.viktz es,7 ;-) • 0 L38 dL39 FO 1/7 RI/CAP LS. 60 2 .26N .41E - 1AWN & FRuir NEE \ ENCROACHMENT 4" %I IEMLOCK ( 0) 00 40 MAPLE WL WL25 15 HLMLO 0 17" MAPLE 30" MAPLE 10 " HEMLOCK A 15 HE ••••• ••••-• • , 20" CEDAR \jL1 WL2O 154 1(11.c.5,K6W T LA ND S 1 t 1\6•1:7- -p ■,/ / 0) MH 26-10 RIM EL. 249.60 I.E. PIPE 111. STEEL M miss PIPE 8' STEEL V 240.75 rtn 8' STEEL s 240.12 kt 240.70 P • • 1/..:355.611 • t.r-265'51 '31" ts.:43.18 .2" MAPLE 0 r3 r, %•- L71 \/L'70 WL 39 1 " MAPLE 0 !VICE 11 330.0 )t . SEWER EASEMENT ■.,N138' 03'22"W _ 1740.00' 20" I, APLE Bl • 15" IIEML 272G /2" REBAR IN 5" sO. N. IN M.C. ti4 26- 9 8111 EL. P.35.10 O'STEIL. PIPE 0' STEEL 5 PIPE. tt'STEEL• BM 240.1 40.0 9.2 lot t"ZsCWZR 111C1111111e= zs • co' N88' 03'22 331.00' FD 1/2" IREBAR W/CAP // 15639 SdcA- 0.10N X 0.06E FIGURE 2: WETLAND FLAGGING/ TOPOGRAPHY BREDBERG & ASSOCIATES, INC. Gig Harbor, Washington 1 . 1 -- slimly QMK'IS2M :E sxn9l3 WETLANDS WETLANDS SURVEY WETLANDS WERE DEUNEATED BY A.J. BREDBERG, WETLANDS BIOLOGIST, ON APRIL 5, 1992 AND • .1*. LOCATED BY JOHN E. CRAMER. P.LS. ON APRIL 7, 1992-' • 6 )1 • 4'. 5sj 5 6 WETLANDS MAIN AREA LESS UPLAND "A" NET AREA WETLAND "B" AREA WETLAND "C" AREA TOTAL WETLAND AREA 12,025 S.F. 378 S.F. 11,647 S.F. 518 S.F. 1,011 S.F. 13,176 S.F. SCALE:1" =30' Z BEARING DATUM: KING COUNTY ENGINEERS WEST UNE OF NW 1/4, SEC.26. T.23N.R4E, WM. CONTOUR INTERVAL = 4'. BENCH MARK: MH 26 -19, N. INV. ELEV. = 248.00'. STRAIGHT PARCEL NUMBERS ARE OLD PARCEL NUMBERS. HALGZED PARCEL NUMBERS ARE NOV PARCEL NUMBERS. WETLANDS BIOLOGIST: ANTHONY J. BREDBERG P.O. BOX 1337 GIG HARBOR, WA. 98335 J .11•11.L14 FIGURE 4:CITY OF TUKWILA WETLAND MAP Jos# 1111 Locations of Inventoried Wetlands in the City of Tukwila BREDBERG & ASSOCIATES, INC Gig harbor, Washington • II I 4. ,11 .11.1 II 315.. • - \.13.M 04 p j \\ Iov* : §EATTLE All p I.� pOle FIGURE 5: BREDBERG & Gig Harbor KING COUNTY SOIL INVENTORY ASSOCIATES, INC. , Washington ST w° Z�i--- I 2 Ur -• _ • APPENDIX A: TUKWILA WETLAND A RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON p9.2 APPENDIX A: TUKWILA WETLAND A RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON • Location in watershed: (If wetland has no inlet or outlet, Score = 0) middle third upper third Score = 3 Score = 2 lower third A Score =1 Score Sly: Is surface water stored in this wetland? yes no Score = 3 Score = 0 Size of wetland: >7 acres Score = 5 0 to 1 acre Score =1 >5 to 7 acres Score =4 >3 to 5 acres Score = 3 For total score, multiply sub -score for storage by sub -score for size. Sub -Score O 1 10.3 acres . Score = 2 Sub - Score -I Total Score 0 Water Quality Residence Time., No outlet Score = 3 movement in outlet but no movement evident in wetland Score =2 Score Z Yegetation Density: 75 -100% of WL covered w/ emergent vegetation Score = 3 •. 50-75% of WL covered w/ emergent vegetation Score = 2 25 -50% of WL covered emergent vegetation 3 Score =1 Score WETLAND A TOTAL SCORE 19 BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON 75 -100% of WL covered w/ emergent vegetation Score = 3 50-75% of WL covered w/ emergent vegetation Score = 2 25 -50% of WL covered emergent vegetation Score= 1 Scoreo? Nutrient Transport WL associated w/ perennial watercourse Score = 3 WL associated w/ ephemeral watercourse Score = 2 Isolated WL (closed depression) Score = 1 Score__ Buffer (barrier function) (consider area w /iri 50 feet of wetand edge) Dense forest or shrub = 75 -100% Score = 3 Dense forest or shrub = 50 -75% Score = 2 Dense forest or shrub = 25 -50% Score =1 Score l Habitat Diversity: 3 or more WL classes, one of which is Open Water Score = 4 1 WL class Score =1 Size of wetland: >7 acres Score = 5 0 to 1 acre Score =1 For total score, multiply sub -score for diversity by sub -score for size. >5 to 7 acres Score = 4 3 WL classes w/ no Open Water or 2 WL classes w/ Open Water Score = 3 >3 to 5 acres Score = 3 2 WL classes w /out Open Water Score = 2 Sub -Score 1 to 3 acres Score = 2 Sub -Score 2 oZ Total Score APPENDIX A: TUKWILA WETLAND 6 RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON . APPENDIX A: TUKWILA WETLAND 8 RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON pg.3 Location in watershed: (If wetland has no inlet or outlet, Score = 0) middle third upper third Score = 3 Score = 2 lower third a Score= 1 Score atim: Is surface water stored in this wetland? yes no Score = 3 Score = 0 Size of wetland: >7 acres Score = 5 0 to 1 acre Score =1 >5 to 7 acres Score = 4 >3 to 5 acres Score = 3 For total score, multiply sub -score for storage by sub -score for size. Sub -Score 0 11:.. "::.res . Score = 2 Sub -Score 1 Total Score 0 Water Quality Residence Time., No outlet Score = 3 movement in outlet but no movement evident in wetland Score = 2 Score 1 Vegetation Density 75-100% of WL covered w/ emergent vegetation Score = 3 50-75% of WL covered w/ emergent vegetation Score = 2 25 -50% of WL covered emergent vegetation Score =1 Score WETLAND B TOTAL SCORE 14 BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON • ` 75- 100% of WL covered w/ emergent vegetation Score = 3 50-75% of WL covered w/ emergent vegetation Score = 2 25 -50% of WL covered emergent vegetation Score =1 Score R- Nutrient Transport WL associated w/ perennial watercourse Score = 3 WL associated w/ ephemeral watercourse Score = 2 Isolated WL (closed depression) Score =1 Score Buffer (barrier function) (consider area w /iri 50 feet of wetand edge) Dense forest or shrub = 75 -100% Score = 3 Dense forest or shrub = 50 -75% Score = 2 many Dense forest or shrub = 25 -50% Score =1 Score 1 Habitat DinEitir 3 or more WL classes, one of which is Open Water Score = 4 1 WL class Score =1 Size of wetland: >7 acres Score = 5 >5 to 7 acres Score = 4 0 to 1 acre Score = 1 For total score, multiply sub -score for 3 WL classes w/ no Open Water or 2 WL classes w/ Open Water Score = 3 >3 to 5 acres Score = 3 diversity by sub -score for size. 2 WL classes w /out Open Water Score = 2 Sub -Score oL 1 to 3 acres Score = 2 Sub -Score Total Score APPENDIX A: TUKWILA WETLAND C. RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON -,..- percentaee of Forested Wetland: 75- 100% of WL is forested Score =4 50- 75% of WL is forested Score = 3 25 -50% of WL is forested Score = 2 Score 0 Duffer Habig (consider arca within 100 feet of wetland edge) Total of all relevant score (check those that apply): A. Diverse forest or shrub =75- 100% score =4 = 50-75% score = 3 . = 25-50% score = 2 = 10-25% score =1 B. Open forest or grass with occ. shrub = 75 -100% = 50-75% = 25 -50% score = 3 score = 2 score = 1 C. Pasture/herbaceous = 75 -100% = 50 -75% score = 2 score = 1 Score y Surrounding land use: (outside of WL buffer, a. forested Score = 3 d. urban: residential/maintained lawns Score = -1 a and or b tota190% Score = 3 wfin 100' fat. Multiply percentage of area in each category.) b. shrub or unmaintained grassland c. active agriculture /grass Score = 2 Score =1 e. urban: industrial/commercial 1 Score = -2 Score — a and or b total 50-90% Score = 2 a and or b total 25- 50% Score =1 0 Score to we : c ec ose appropria c raptor nest structures Snags >= 10 inches dbh, >20 feet tall or beaver or muskrat lodges Score = 3 for each Score = 2 if present Snags <10 inches dbh Fallen logs Perches Score = 1 for each Score Presence of water. Permanent Score = 3 Seasonal Score =2 If permanent water is greater than 2 feet deep during driest season, add 2 points Score °Z � _ g.2 APPENDIX A: TUKWILA WETLAND G RATING FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON • Water Storage Functions Location in watershed: (lf wetland has no inlet or outlet, Score = 0) middle third upper third Score = 3 Score = 2 lower third a Score =1 Score Siam: Is surface water stored in this wetland? yes no Score = 3 Score = 0 Size of wetland: >7 acres Score = 5 0 to 1 acre Score =1 >5 to 7 acres Score = 4 >3 to 5 acres Score = 3 For total score, multiply sub -score for storage by sub -score for size. Sub -Score 0 1 to 3 :acres . Score = 2 Sub -Score 1 Total Score Water Quality Residence Time: No outlet Score = 3 movement in outlet but no movement evident in wetland Score = 2 Score a Vegetation Density: 75 -100% of WL covered w/ emergent vegetation Score = 3 •• 50-75% of WL covered w/ emergent vegetation Score = 2 25 -50% of WL covered emergent vegetation a Score= 1 Score WETLAND C TOTAL SCORE 17 BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON pg.3 DATA FORM 'J _ ROUTINE ONSITE DETERMINATION METHOD? Field (• J • Jae ��'!`�I Date• ii7. /q 2 Proect/Site• h1 l erc' t" TkKul.t.J.I State. tr)4 County: !�1' Applicant/Owner. Le k`' °\ Acs we, Plant Community #/Name• W t /QNc A 'We r'ir.ict P/4.✓h Note: If a more detailed site description is necessary, use the back of data form or a field notebook. Do normal environryiental conditions exist at the plant community? Yes No V (If no, explain on back) all ra o e ( p. f Has the vegetation, soils, and/or hydrology been significantly disturbed? Yes •V No (If yes, explain on back) id _1 eu „e I P' VEGETATION Indicator Indicator Dominant Plant Species Status Stratum Dominant Plant Species Status Stratum 1. skv,ilk Gu41a3e 11 2, Sf.'1 r,� ,r/o44- c kl 1/ 12 3, RecI4,141er rite. T 13 4. 5& !Arta,✓ i� re m.o. 5/5 14. 5, Oa ter Par s / 1 UgL # 15 6. 16 7, 17 8. 18. 9. 19 10. 20 Percent of dominant species that are OBL, FACW, and/or FAC /D v Is the hydrophytic vegetation criterion met? Yes t/ No Rationale. SOILS Series/phase: Alc.f 4 hvo.✓ f Alm cic Subgroup.2 Is the soil on the hydric soils 1,15t2 Yes ✓ No Undetermined Is the soil a Histosol? Yes No Histic epipedon present? Yes No Is the soil: Mottled? Yes ---- No • Gleyed? Yes. ✓- No Matrix Color: 2 - s J .$ a < < Mottle Colors. Other hydric soil indicators: a Is the hydric soil criterion met? Yes IV No Rationale: HYDROLOGY te Is the ground surface inundated? Yes ✓ No Surface water depth: / Is the soil saturated? Yes ✓ No Depth to free- standing water in pit/soil probe hole. List other field evidence of surface inundation or soil saturation. Is the wetland hydrology criterion met? Yes r✓ No Rationale: JURISDICTIONAL DETERMINATION AND RATIONALE Is the plant community a wetland? Yes (-Zr No Rationale for jurisdictional decision. 1 This data form can be used for the Hydric Soil Assessment Procedure and the Plant Community Assessment Procedure. 2 Classification according to 'Soil Taxonomy." APPENDIX B: TUKWILA WETLAND A DATA FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON DATA FORM ROUTINE`ONSITE DETERMINATION METHOD1 / Field Investigat • 4s): . . ,~ • ! I'e ��.d l,i,4 Date: ' r/9 Project/Site. k e r r' , State: Id County• l .--/A Applicant/Owner. Le Rc& A, u.e: Plant Community #/Name• c e4 i 4 9 4/314,44 Note: If a more detailed site description is necessary, use the back of data form or a field notebook. Do normal environmental conditions exist at the lant gg mmunit ? Yes No r/ (If no, explain on back) p old to vt 1' r -` Has the veegq,etation, soils, and/or hydrology been significant disturbed? Yes L/No (If yes, explain on back) ti ra v e/ f Indicator Dominant Plant Species Status Stratum Dominant Plant Species 1. /eaF tea, /e ct� r 2,Px .4 ire FAFA c 11 f 12. 3. Red Elder -k.err 5/S 13 4. 11,,+44 /h4131€ PA e- S4f 14 5. �.✓d:a,✓ PIu, FAcli. 5(s 15. / 6. tfi ? • t (sa. y a.P (ciao{: ber'`� %,(C �( /' .✓C 16 7. d J 17 8. 18. 9. 19 10. 20 Percent of dominant species that are OBL, FACW, and/or FAC /f3 Is the hydrophytic vegetation criterion met? Yes No I/- Rationale: VEGETATION Indicator Status Stratum / SOILS Series/phase: Zi/ c(t 4 N a A. Subgroup•2 Is the soil on the hydric soils list? Yes No ✓ Undetermined Is the soil a Histosol? Yes No // Histic epipedon present? Yes No Is the soil: Mottled? Yes No ✓ Gleyed? Yes No Matrix Color: /'ve 6.4' Mottle Colors. Other hydric soil Indicators: Is the hydric soil criterion met? Yes No ✓ Rationale: HYDROLOGY Is the ground surface inundated? Yes No t/ Surface water depth. Is the soil saturated? Yes No Depth to free- standing water in pit/soil probe hole: List other field evidence of surface inundation or soil saturation. Is the wetland hydrology criterion met? Yes No Rationale: JURISDICTIONAL DETERMINATION AND RATIONALE Is the plant community a wetland? Yes No Rationale for jurisdictional decision. 1 This data form can be used for the Hydric Soil Assessment Procedure and the Plant Community Assessment Procedure. 2 Classification according to "Soil Taxonomy." APPENDIX B: TUKWILA WETLAND A DATA FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON DATA FORM _ ROUTINE ONSITE DETERMINATION METHOD1 Field Investigatgr(s): .4 . J . t3 d'e LI. /�y 1. Date. i/5—/ 9 2 Project/Site• I f • e rci r �t State: County* Applicant/Owner 1P k ° °` Av�1. Plant Community 1/Name• 1 Sla.v4 A- I.e/efrAd Note: If a more detailed sit description Is necessary, use the back of data form or a field notebook. Do normal environmental conditions exist at the plant community? Yes No L' (lino, explain on back) G/e/ e- a ✓e ( P1 4. Has the vegetation, soils, and/or hydrology been significantly disturbed? Yes ✓ No (If yes, explain on back) O (d _if uv c f %P,- f VEGETATION Indicator Indicator Dominant Plant Species Status Stratum Dominant Plant Species Status Stratum 1. e e446 3 .e 061- I/ 11 2. 12 3. 13 4. 14. 5. 15 6. 16 7. 17. 8. 18 9. 19 10. 20. Percent of dominant species that are OBL, FACW, and/or FAC Af'v Is the hydrophytic vegetation criterion met? Yes 1' No Rationale. SOILS Series/phase: hor^s.a /6` ,„4. ////4„,...k. Subgroup•2 Is the soil on the hydric soils iisg. Yes ✓ No Undetermined Is the soil a Histosol? Yes No Histic epipedon present? Yes No Is the soil: Mottled? Y s � No Gleyed? Yes y No Matrix Color: -2'5r 372- Mottle Colors. Other hydric soil indicators: Is the hydric soil criterion met? Yes . ' No Rationale. HYDROLOGY Is the ground surface inundated? Yes Nov Surface water depth. Is the soil saturated? Yes t/ No Depth to free - standing water in pit/soil probe hole. ..3 List other field evidence of surface inundation or soil saturation. Is the wetland hydrology criterion met? Yes t-' No Rationale: JURISDICTIONAL DETERMINATION AND RATIONALE Is the plant community a wetland? Yes '' No Rationale for jurisdictional decision: 1 This data form can be used for the Hydric Soil Assessment Procedure and the Plant Community Assessment Procedure. 2 Classification according to "Soil Taxonomy." APPENDIX B: TUKWILA WETLAND 8 DATA FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON DATA FORM ROUTINE ONSITE DETERMINATION METHOD1 Field Investigatq (s): . . ti-• 1 I'e LJ lei" " Date: i /5— 9 2 ProjecVSNe• State• Coun�tryy s Al AppllcantlOwner• Le k Plant Community #/Name We PA) B C p aA Note: If a more detailed sit &description is necessary, use the back of data form or a field notebook. Do normal enviroo mental conditions exist at the plant community? Yes No (If no, explain on back) of Has the vegetation, soils, and/or hydrology been significant1 disturbed? Yes L- No (If yes, explain on back) v (1 j r 4 v e / r �- Dominant Plant Species AGk 2. _4A' "1l" /fit' 3. a A.✓act/ ■Lsf /e e 4. 5. 6. 7. 8. 9. 10. VEGETATION Indicator Indicator Status Stratum Dominant Plant Species Status Stratum e 11 G/ 12. P*r t4 13. 14 15 16 17 18 19. 20 Percent of dominant species that are OBL, FACW, and/or FAO 3 3 Is the hydrophytic vegetation criterion met? Yes No Z/ Rationale* SOILS Series/phase: - 1,41ka.✓v (a Subgroup•2 Yes No 1-' Undetermined No 1/ Histic epipedon present? Yes No No --V- Gleyed? Yes No Mottle Colors: Is the soil on the hydric soils list? Is the soil a Histosol? Yes Is the soil: Mottled? �� R Matrix Color: f' G Other hydric soil indicators: Is the hydric soil criterion met? Yes No c/ Rationale: HYDROLOGY Is the ground surface inundated? Yes No Surface water depth: Is the soil saturated? Yes No L- Depth to free - standing water In pit/soil probe hole: List other field evidence of surface inundation or soil saturation. Is the wetland hydrology criterion met? Yes No tl Rationale: JURISDICTIONAL DETERMINATION AND RATIONALE Is the plant community a wetland? Yes No tV' Rationale for jurisdictional decision: 1 This data form can be used for the Hydric Soil Assessment Procedure and the Plant Community Assessment Procedure. 2 Classification according to "Soil Taxonomy." APPENDIX B: TUKWILA WETLAND 8 .0 DATA FORMS BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON DATA FORM ROUTINE ONSITE DETERMINATION METHOD1 Field Investlgator(s): •'/ . • J • 31'e d t c''I',i Date. 2//5—/9 Project/Site• 'I 1ercSI- TkiG ».tJ <State: Coun � "' Applicant/Owner• Le 1IP. k 0 � t'- Plant Community 0/Name. We tl4,t.dd C i✓e f .t..,1 Note: If a more detailed sit description is necessary, use the back of data form or a field notebook. Do normal environmental conditions exist at the plant community? Yes No ✓ (If no, explain on back) 6/d /3c.. r re.> Has the vegetation, soils, and/or hydrology been significantly disturbed? Yes l" No (If yes, explain on back) (c/ g„, r pow P 7` VEGETATION Indicator Indicator Dominant Plant Species Status Stratum Dominant Plant Species Status Stratum 1. •,S71-,'... ! ry /4/7 /e Ai 11. 2. S�a,✓f1 C-'a 46u 3 e w y 12 3 13 4. 14 5. 15 6. 16 7. 17 8. 18 9. 19 10. 20 Percent of dominant spedes that are OBL, FACW, and/or FAC /' Is the hydrophytic vegetation criterion met? Yes v No Rationale. SOILS Series/phase: �O r-. q O i','t�kG K Subgroup .2 Is the soil on the hydric soils list? Yes v No Undetermined Is the soil a Histosol? Yes V No Histic epipedon present? Yes y No Is the soil: Mottled? Yes 1— No Gleyed? Yes No Matrix Color: 2 5-k' ...77-2_ Mottle Colors. Other hydric soil Indicators: -- Is the hydric soil criterion met? Yes No Rationale: 1.. i � / HYDROLOGY Is the ground surface inundated? Yes -�f No Surface water depth. Is the soil saturated? Yes No If Depth to free- standing water in pit/soil probe hole: t List other field evidence of surface inundation or soil saturation. Is the wetland hydrology criterion met? Yes 1.i No Rationale: JURISDICTIONAL DETERMINATION AND RATIONALE Is the plant community a wetland? Yes No Rationale for jurisdictional decision' 1 This data form can be used for the Hydric Soil Assessment Procedure and the Plant Community Assessment Procedure. 2 Classification according to 'Soil Taxonomy APPENDIX B: TUKWILA WETLAND C DATA FORMS B -2 BREDBERG & ASSOCIATES, INC. GIG HARBOR, WASHINGTON TABLE 1. Vegetation listed by genus species, common name, and National Wetland Indicator (NWI) status for the wetlands and uplands. Genus species (Common Name) NWI RA WETLAND PLANTS TREES: Alnus rubra (Red Alder) FAC 25% SAPLINGS: NONE SHRUBS: Rubus spectabilis (Salmonberry) FAC 15 HERBACIOUS: Lysichitum americanum (Skunk Cabbage) OBL 10 Urtica dioica (Stinging Nettle) FAC 10 Oenanthe sarmentosa (Water Parsley) OBL 5 Equisetum arvense (Field Horsetail) FAC 5 \� TABLE 1(CON) Vegetation listed by genus species, common name, and National Wetland Indicator (NWI) status for the wetlands and uplands. Genus species (Common Name) NWI RA UPLAND PLANTS TREES: Acer macrophyllum (Bigleaf Maple) FACU 25 Alnus rubra (Red Alder) FAC 35 Pseudotsuga menziesii (Douglas Fir) UPL 20 Tsuga heterophylla (Western Hemlock) FACU 15 SAPLINGS: Acer circinatum (Vine Maple) FACU 5 SHRUBS: Osmaronia cerasiformis (Indian Plum) FACU 10 Sambucus racemosa (Red Elder) FACU 10 Rubus spectabilis (Salmonberry) FAC 10 VINE /LIANA Rubus discolor (Himalayan Blackberry) FACU 20 HERBACIOUS: Polystichum munitum (Sword Fern) FACU 5 Hedera helix (English Ivy) FACU 5 Urtica dioica (Stinging Nettle) FAC 10 Weld,. or