Loading...
HomeMy WebLinkAboutSWP272727 PF(—%FIVEQ Nu t; L ') 1997 DEVELOPMENT PUNNING F RENTON : : r :.::.: ` ` R : .: . _4..::: " ' .. : ::: : :::::.:: :".::::::: : : ::: : :: R: :: : : : ::::>::;:;:; : : . : >». ..:...... .::..:. . . . .. . :: F:: :;:; :;: : J; ; . ; . 4. .. A i ft ...4........:............. N ' k ' ` ::::%::::..:::::::::::::::: .:::..r...::::::::::::::::::::::::.:::::::::::::::::::.:::::::......;:::::::::::..:::::::::::::::::::::::::::::::::::::.. X. 4. OUR JOB NO. 6116 �D OCTOBER 1997 9 o �. . ow 101301i 2 NAL.E�6 Prepared By: I EXPIRES G-I I-9 BARGHAUSEN CONSULTING ENGINEERS, INC. 18215 72ND AVENUE SOUTH KENT, WASHINGTON 98032 (425) 251 -6222 �G VS m�.. �2 �a CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES `2 � ° 'N."." TABLE OF CONTENTS 1.0 GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 UPSTREAM DRAINAGE ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 ON-SITE DRAINAGE ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0 DOWNSTREAM DRAINAGE SYSTEM DESCRIPTION AND PROBLEM SCREENING . . . 5.0 RESOURCE REVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. BASIN RECONNAISSANCE SUMMARY REPORT . . . . . . . . . . . . . . . . . . . . . . . . B. CRITICAL AREA DRAINAGE AREA MAPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. FLOODPLAIN FLOOD WAY FEMA MAPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. OTHER OFF-SITE ANALYSIS REPORTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E. SENSITIVE AREA FOLIOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F. SWM DIVISION DRAINAGE COMPLAINTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.0 U.S. DEPARTMENT OF AGRICULTURE SOILS SURVEY . . . . . . . . . . . . . . . . . . . . . . 7.0 WETLAND INVENTORY MAPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.0 CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.0 APPENDIX APPENDIX Exhibit A Vicinity Map Exhibit B Drainage Maps Exhibit C Off-Site Analysis Drainage System Table Exhibit D Assessor's Map Exhibit E Basin Study Exhibit F Sensitive Areas Folio Exhibit G Wetland Inventory Map Exhibit H Drainage Complaints Exhibit I King County Soil Survey 6116.003 [BAH/sm] 1.0 GENERAL INFORMATION The site analysis was conducted on July 9, 1997. The weather was cloudy and rainy. The proposed project consists of two retail buildings, a QFC Market/Retail Anchor. The site's total area is approximately 8.3 acres. The project is located in a portion of the Southeast quarter of the Southwest quarter of Section 10, Township 23 North, Range 5 East, Willamette Meridian, Renton, Washington. Based on a more localized description, the property is located on the northeast corner of the intersection of Duvall Avenue N.E. and N.E. 4th Street. Currently there are portions of the site that have impervious asphalt paving. However, the majority of the site consists of second-growth trees and underbrush. The general topography of the site is sloping toward the south at approximately 0 to 5 percent. 2.0 UPSTREAM DRAINAGE ANALYSIS ' The project receives upstream sheetflow from the north and northeast. The approximate area of sheetflow is 8.8 acres. From the site investigation, the majority of the upstream area is second- growth timber and underbrush. It does not appear that our site receives a substantial amount of drainage from this upstream area. The majority of the upstream sheetflows into the existing wetland on the east portion of the site. 3.0 ON-SITE DRAINAGE ANALYSIS Current conditions for the project consist of sheetflow drainage that generally run from the north to the south of our project. The sheetflow is collected in a roadside ditch that runs east and west along N.E. 4th Street. The flow accumulates near the east property line and heads through an 18-inch culvert to the south. 4.0 DOWNSTREAM DRAINAGE SYSTEM DESCRIPTION AND PROBLEM SCREENING For a more detailed description of the downstream drainage system, please consult Exhibit "B," Basin Maps, and Exhibit "C," Off-Site Analysis Drainage System Table. The downstream drainage system for this project exits the site near the southeast corner. The drainage collects and heads under N.E. 4th Street through an 18-inch concrete culvert. On the south side of the street, the drainage exits into an open channel and heads toward the south. The open channel then enters into what appears to be a King County detention facility and then exits that facility to the southeast. The existing flow enters into an open channel and again heads in a southerly direction. Once the drainage reaches S.E. 132nd Street, it enters into an 18-inch tightline system that heads to the south through the residential neighborhoods. From a conversation with neighboring residents and a review of the assessor's map, it appears that King County has established drainage easements through the residential housing to convey upstream drainage to the south. From there, the drainage continues to the south until it flows into the Cedar River several thousand feet away from our site. _ 6116.003 [BAFUsm] Through a site investigation and conversations with the neighboring residents regarding problems in the downstream area, it appears that some flooding occurs in the area of S.E. 133rd Street during high level flows. Through a conversation with the resident, it appears through King County's site investigations that an undersized culvert was installed near the intersection of S.E. 135th Street and 142nd Avenue S.E. He also explained that King County plans to improve this culvert section in September of 1997. Other than this flooding and slight erosion in the open channels, the downstream area for this project appears to have no major capacity or erosion problems. 5.0 RESOURCE REVIEW The following is a description of each of the resources reviewed in preparation of this Level 1 Drainage Study: A. BASIN RECONNAISSANCE SUMMARY REPORT This site is included within the Cedar River Basin and the lower Cedar River Sub-basin. A Basin Reconnaissance Summary Map can be seen in Exhibit "E" along with the FEMA floodplain maps for this area. B. CRITICAL DRAINAGE AREA MAPS This site is located within the critical drainage area of the Cedar River. C. FLOODPLAIN FLOODWAY FEMA MAPS Please see Exhibit "E" for a copy of the FEMA map for this area. After review of the FEMA map, it was determined that our site is not within a floodplain. D. OTHER OFF-SITE ANALYSIS REPORTS A review of area maps, a site investigation, and basin study were reviewed for analysis and preparation for this Level 1 Drainage Study. E. SENSITIVE AREA FOLIOS Each of the sensitive area folios that was associated with this area was reviewed. After review, it was found that the subject property incorporates no sensitive areas. F. SWM DIVISION, DRAINAGE SECTION COMPLAINTS The drainage complaints for this area were reviewed that were adjacent to our downstream from our site. The list of complaints and applicable reports can be found in Exhibit "H" of this report. The underlined complaints are the ones that pertain to our project. Reports for these complaints can be obtained from King County upon request. 6116.003 [BAH/sm] 6.0 U.S. DEPARTMENT OF AGRICULTURE SOIL SURVEY The U.S. Department of Agriculture Soil Survey for King County has been incorporated in this report and can be found in Exhibit "I." 7.0 WETLAND INVENTORY MAPS Wetland inventory maps were reviewed for this project. It does not appear that the project lies within an area where any wetlands were inventoried. 8.0 CONCLUSION The downstream area for this project appears to have no major downstream-related problems. All drainage segments that incorporate the downstream area appear to have adequate capacity for existing flows. From our analysis of this project, we feel that there will be no adverse impact to the downstream system if development to the property incorporates standard City of Renton Stormwater Control Standards. 6116.003 [BAH/sm] EXHIBIT A VICINITY MAP zAV GRANT AV 0 am c soo .,. I PARK AV N GRANT GRA i HiG4 'AVM S fi .N Joys ar s "Ar' � ♦ ^v� 9 J �:� k ✓ .Q � s ,1 ;,fir � �3, _,fir � ';•,�J' ,x � � ` 1 a '' y_a ,� 1 A t` ,� +iG� _'! r ..� �.,►C,; 'y� ,xr� JONEs YwAy ,:.,. S: 00y KIK CK A NE1410 AV i s 11Iti F x AV E atr T r i ACNE AlE Y .. �l,>TM Av v SE Al S JEFFERSON A uiQF nnE ` ' NE rfERSM M E - yi. KIRKLAN V +i qti��+ � Ir�E s5 a� /: H � m �. AV NE ! _t ■ g yN xl�F k3 X- ti 4 k ,�x ±{Ms"A ,� *.y.l .r ;` � ■ �-,I,.: � YNM,000 : AY �rM y� `� 1H _4� T,�QA 6 RE '. S SD 1000 r MONROE NE Qr ..��.1- ��:■ vM : YW AV NE Y. HSi g 35•lY It 3S AY n �•- W.A Y : 7 .� f A {,S • 'a' n__ 12NTH Ar F S C� 7 � i�+ai � i 'F ,'�r ti.4 Y �h � I ^� � '�,�+ .� � 4 A. • .8.. / � ra YR z 2t .SF Nv1� `q„ ,F,^ \ �. .�. S.F�•�. !8� 9ElTb1 AY ' f �sr �,�,F• •* fi (�r� �'a �1 ,n ON :%`! f AY -S�T� 6`a„�� �� Aww,�r a4 UNIO;4AV'-. NE pNn 3 A fi t'^ ��I T D \\ >s Fay 8 ;pav AV R V VASM AY AY aF 1367N `M 1 VIE C' i O r �. 'iy 1 J ^,`' AV' SE r wolws0n • r[: � AV K CD ib viu V� zd1. ,"�•-� '* I �• '^ + �� ]38TN 1'^ A .F.. _137TH _ AV __NE d K i BgpEKTON. YY f 138TH AV 138TH X =i AV K _� 3 .rfr o r MM n Y 1 = N r S '�� r f ALL AV) 1 R Al A ,A,sr 31 _ T �G `TM = F ,a�n TH AY i$- <,a;� .r sc s 3 gR _ �,u T:r '� ~ r= e a ` 113AD` y 70. T 1NO~ AV SE 81 Ay NE ,A ]LL/4TH AV SE AV �.� fn = ^' S 7RR rEa xi. 1447H 3 AV E m it ` AV r. us W. Ar sE I� � � � py�Az SETM , A'AniF°i.t 7i1 u7TH F 1C o,1 46TH •y AV SE y n _.i,/� y AeTH n J '�` r; SE Sf �%/", `19TH 'p�,,,v1 1 , LM148TH Ay SE M - n 7 uFH AY / rrla r v Ty EXHIBIT B DRAINAGE AREA MAP IA E6 1- 13116 x — S ,L6 NE..,.I.th IL. 86 1 r•,., ry C w AR �' •. : . ................».........-:,.:...f nn , NE 7th.:$t..r NE 6th Pt LJ NE:� 'thCt _....-11 ........ f W SE 122nd St 1.:86 '4' `" ? Z 1.. . .............::�........... Cl- Cc ,........,:.::..... .. :, .y to ..i ..i......., ...:.:.�:........ :..w.......:t .......... C'kp .... i , , 86-3 z.... .. V • ¢ g:.:... NE 6th Ct /:.._ .'jam y©..... >.w. <........ rwnte Dr ..: .......... r , r a..v-z µ A N 4th SE 12 _.............< St .i,.B7-3 / ........: ; ...... ........ . ........ # 4.37-3 1.1,E7-1 i ........ ..... -...... _. .._. Z E is NE...Sth,U)• ...�.............. .,,,.�� . ...........� i 6 t 1 14}4-3 :,,88-6 c ! _ 14.38-7 -.......... L Z : ......... i S Qsop jN.BB.. i t3FH-S 13l19-4 14J8-9 :,..,........ �w ... x ,,.,.... .. 1992-1 :19.82-3 I i :0.B2-S i t s.. ...... :19.B2-4 I i ......... s f s . J9,82-10� _ I 3 19.82-8 ....... 19,82-9 H 5315 NW 1/4 III'llpi, I, I �II�'�� II r o _ 1 RENTON — 155AQUAH ROAD � 0 .,OeD o ❑ a 0 0 dAf Al 0 ❑o adolrcc cro fv 4..., C-C ruj rl 13 ~ P ell t40o `'' ❑o O C oi 00 nwt 400 � oCL CICD ,q .�_.... -ram ❑ 400 _ ,I- 11 000 = 15 _ D 11 7 t o[ � 3 250 EXHIBIT C OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE Basin: Cedar River Subbasin Name: Lower Cedar Creek Subbasin Number: .. _. ... ................................................ X. ......a.....:::: i: r"i .......: :i a.. :.:..:..... lxzta :frizz anew[:::>::... Ira�na c.Gc�m'ceut <»:> 1v Iistanc ::.. acts Potn1:<:<::::>::>:::<::<::::! seations: a ::ileld:: ec€az ...:.. ...... .............P............... :...::.::::::. ::.............g............ .................. g ...........P................. ..:.::::::::::::.. ....::::.::::...::::::::::::::::.........::...:...... .:....: ::::..::::.::.:.:::::::::::::::::::::::::::..:::::::::::::::::::.... :::: .....a :. err.:..:... ..:;.;:.:......... ? :.::: ::::..:.. ... E >::;::;...: .1t ::;::>:»»::»»:::>::»:> ' tlldt E.. 1?# ':�# s..............r................................................. ......usCl:... I.:::::::::::::....:::::.:.::::::::::::::::::::: T .:a1 'x::::.::::::...: C ..: W�:.........:::::::.......................:::::::::::..::::.::::.................... .....................a................. ...... ........... ...................................................................... ............. .............................................................................. ......................................................................................................................................................... .. .:. ::>::>::>:: :.; » >;::: l ischa ......._> `::>'::>: ..:..... .....) esztient .. ... See Map Type: sheet flow, Swale, stream, Drainage basin,vegetation,cover, % Ft Constrictions,under capacity,ponding, Tributary area,likelihood of problem, channel,pipe, depth, type of sensitive area, volume overtopping,flooding,habitat or organism overflow pathways,potential impacts pond; size,diameter, surface area destruction,scouring,bank sloughing, sedimentation,incision,other erosion 1 18 Inch Concrete Culvert under N.E. 4th Street 1 0 - 80 None None None observed. 2 Open Channel Vertical ss, 10' bw, 3' deep 1 80 - 580 Slight erosion Erosion Slight erosion of bank due to earth lined high flows. 3 Open Channel 10' bw, 3:1 ss, V deep, 1 580 - 930 None None None observed. marshy area 4 18 Inch Concrete Culvert Outlet on detention pond 1 930 - 980 None None None observed. 5 Open Channel 3' bw, 2:1 ss, 2' deep, grass 1 980 - 1280 None None None observed. 6 18 Inch Tightline Tightline lined through housing 1 1280 - Flooding Flooding Neighbor reports flooding due development 2000+ to downstream undersized culvert. King County to fix in summer of 1997. 6116.004 [BAH/kn] EXHIBIT D ASSESSOR'S MAP /GS-IL IZS /rS. 3 I ASSESSOR'S MAP ; .3 m ri b - Ik a M ( — - z91 zo TR.B NZ N 63 S8 n�p�i ,s ac 1 2 O � � ,� 73 l J 60Ei o3 _ 4Z �!2 6o'S.oa Q, /9o,a5 77-4F 60 g-f.33' Z. N.e .to s sv. -2 So 274.02 3Z4.02 , ej h ' Os - /Z 7 04E Z73.8) j ` 6 1 by g ° N Kh nl .._ I U 79��0 -3o y. M`A • �N 80. 9y I u N z a 8 s- �►� ^ q 69 V j N ` �/ 3v 3o N � 3 A� I°� Q I "► �•� to 6� log I o SLJ °� _ 1---- ,>s o 8G `' °1, V K J aS p orb 0 ki ♦ Zo' 10,993 0 Sk o to 1 I RENT Z1A. L uA . 94.07 3 y / /y o; 0. o ,Q o 0 0 �+ 7o.o1c zir• 49 wt�. F I Ob 2 b 0 �s— r � � •- iso - I � �,' v �N I / a 0 3661 8b 3�2�� sd a ( 02 s•� $ sr, �1 P` a¢A` Z''�c. ti / �'j //3 N \ O1 'JCP�p 3 ,.• I ° n RE NTON ORD. 3SiS S3o /cer/Y _ _a3 * .c To. 7cl ( .35 _ 3t3.z�t 4Sea/3Ls Soo/359 —6 .!, �raitla..4i ccsl i f6No/36/ RS99/ Sl6- RfNTb.I o.CQ. 447o 4x-.F.Fs- — — 9ee3/ GGS REt4rbM ORv. ?4� O TQ O / 9f u + InSE. 128TH. ST. ;'° .��.14 .VFY - � hl SE. 128TH. ''ram• L G rr.' ,tn, 670GZ41488 S E-12 8 TH ST a `, 4620 347 * /Qo/ =/7-4 w .63PE3 ,ts [6 i. 5 95 e -Lid/d✓9 -fS1�.S/�°i° �L3o t1 V � 12,1612 i .16I Z1 /.f s' 4687/627 l23.03 �O ioe so ,� 7 �.� /7�.q 3 .2-f0 /140.Jrz 1! /�/ /�/.i6 -6d�.//87.7060 �•` Zo 3oe z i EXHIBIT E BASIN STUDY k NATIONAL FLOOD INSURANCE PROGRAM NATIONAL FLOOD INSURANCE PROGRAM M FIR r FIRM FLOOD INSURANCE RATE MAP FLOOD INSURANCE RATE MAP KING COUNTY, WASHINGTON AND KING COUNTY, INCORPORATED AREAS WASHINGTON AND INCORPORATED AREAS PANEL 981 OF 1725 (SEE MAP INDEX FOR PANELS NOT PRINTED) PANEL 982 OF 1725 (SEE MAP INDEX FOR PANELS NOT PRINTED) is CONTAINS: COMMUNITY NUMBER PANEL SUFFIX CONTAINS: COMMUNITY NUMBER PANEL SUFFIX KING COUNTY, UNINCORPORATED AREAS 530071 0981 F RENTON,CITY OF 530088 0981 F KING COUNTY, UNINCORPORATED AREAS 530071 0982 F RENTON,CITY OF 530088 0982 F i i 13 MAP NUMBER ;t 53033C0981 F MAP NUMBER 53033CO982 F { MAP REVISED: v�G�yCY MA��F MAY 16, 1995GYaN MAP REVISED: Wx MAY 16, 1995 �P A' L• Federal Emergency Management Agency Federal Emergency Management Agency Y Z� �J V H aeJ JFI`eA' "Fle..�..... ,.. F��♦ ' I U) w z O o z z 10 N W D m0 u- U w CD D } z z F- w Y c U CITY OF RENTON 530088 SOUTHEAST 126TH STREET ¢ w w � ~ w 0 U z Z F- 0 v 3TH STREET 128TH w w N w Z z w ZI Q w Q 2 F- cn N M ¢ W S z p 0 0 SOUTHEAST 129 z Z PLACE w �- m O 11 U KING COUNTY Q UNINCORPORATED AREAS C7 530071 Z U w z � SOUTHEAST PLACE 132Np NOHTHwEg1 15S V) _ H � r� J W H- Q ~ I CC w O = n- �- CC o O N U SOUTHEAST 2ND PLACE SOUTHEAST 136TH SOUTHEAST 136TH STREET STREET z w z„ N P51 3P0 S�PE�� O I n 15 P N 3R� SOUTHEAST RECONNAISSANCE REPORT NO. 13 LOWER CEDAR CREEK BASIN JUNE 1987 Natural Resources and Parks Division and Surface Water Management Division King County, Washington King County Executive Tim Hill King County Council Audrey Gruger. District 1 Cynthia Sullivan, District 2 Bill Reams, District 3 Lois North, District 4 Ron Sims, District 5 Bruce Laing, District 6 Paul Barden, District 7 Bob Grieve, District 8 Gary Grant, District 9 Department of Public Works Parks, Planning and Resources Don LaBelle, Director Joe Nagel, Director Surface Water Management Division Natural Resources and Parks Division Joseph J. Simmler, Division Manager Russ Cahill, Division Manager Jim Kramer, Assistant Division Manager Bill Jollv, Acting Division Manager Dave Clark, Manager, River & Water Derek Poon, Chief, Resources Planning Section Resource Section Bill Eckel, Manager. Basin Planning Program Larry Gibbons, Manager, Project Management and Design Section Contributing Staff Contributing Staff Doug Chin. Sr. Engineer Ray Heller. Project Manager & Team Leader Randall Parsons, Sr. Engineer Matthew Clark, Project Manager Andy Levesque, Sr. Engineer Robert R. Fuerstenberg, Biologist & Team Leader Bruce Barker, Engineer Matthew J. Bruengo, Geologist Arny Stonkus, Engineer Lee Benda, Geologist Rav Steiger, Engineer Derek Booth, Geologist Pete Ringen. Engineer Dvanne Sheldon, Wetlands Biologist Cindv Baker, Earth Scientist Di Johnson, Planning Support Technician Robert Radek, Planning Support Technician Randal Bays, Planning Support Technician Fred Bentler, Planning Support Technician Consulting Staff Mark Hudson, Planning Support Technician Sharon Clausen, Planning Support Technician Don Spencer. Associate Geologist, Earth David Truax. Planning Support Technician Consultants, Inc. Brian Vanderburg, Planning Support Technician John Bethel. Soil Scientist, Earth Carolyn M. Byerly, Technical Writer Consultants, Inc. Susanna Hornig. Technical Writer Virginia Newman, Graphic Artist Marcia McNulty, Typesetter Mildred Miller, Typesetter Jaki Reed, Typesetter Lela Lira, Office Technician Marty Cox, Office Technician P:CR TABLE OF CONTENTS I. SUMMARY 1 II. INTRODUCTION 1 III. FINDINGS IN LOWER CEDAR RIVER BASIN 2 A. Overview of Basin 2 B. Effects of Urbanization 4 C. Specific Problems 5 1. Drainage and flooding problems 5 2. Damage to property 6 3. Destruction of habitat 6 IV. RECOMMENDATIONS FOR ACTION 7 A. Reduce landslide hazards 7 B. Reduce erosion and flooding 7 C. Prevent future erosion and flooding with appropriate analysis, S planning, and policy development D. Stop present (and prevent future) damage to habitat 3 by addressing specific problems in stream systems V. MAP 11 APPENDICES: APPENDIX A: Estimated Costs A-1 APPENDIX B: Capital Improvement Project Ranking B-1 APPEDDIX C: Detailed Findings and Recommendations C-1 I. SUMMARY The Lower Cedar River Basin, in southwest King County, is unique in its development pat- terns and the associated environmental problems that appear throughout the basin. Except for the city of Renton and areas on the Cedar River Valley floor, most of the development in the basin has occurred on the upland plateaus. Most of this development is recent and primarily residential. In addition, the plateau is the site of numerous sand and gravel mining operations and, in the southern uplands, an abandoned coal mine. Peat is also being mined north of Otter Lake. In some areas livestock are being raised on small farms; there are no major crop-related agricultural activities in the basin. The effects of development are most apparent where storm drainage is routed over the valley walls. Impervious surfaces on the plateau have increased the rate and volume of storm runoff, resulting in substantial erosion, siltation, and flooding below. In addi- tion, erosion and siltation have damaged or destroyed habitat in many tributaries, threatening the survival of fish. Habitat and water quality throughout the basin are also threatened by the filling of wetlands and the presence of large amounts of domestic trash in some streams. The reconnaissance team noted that the Peterson Creek system has so far remained in its natural, nearly pristine condition. Maintaining this quality should be a high priority in future basin planning capital project programs. Recommendations in the Lower Cedar River Basin include 1) designing and constructing appropriately sized RID and other drainage facilities; 2) establishing stricter land use policies regarding floodplains, wetlands, and gravel mining; 3) conducting more detailed and comprehensive hydraulic/hydrologic analyses of proposed developments; and 4) preventing damage to the natural drainage system. The field team also recommends 5) restoring the habitat of several tributaries (e.g., cleaning gravels, revegetating stream banks, and diversifving streambeds for spawning and rearing) as well as 6) protecting the nearly pristine quality of Peterson Creek- U. INTRODUCTION: History and Goals of the Program In 1935 the King County Council approved funding for the Planning Division (now called the Natural Resources and Parks Division), in coordination with the Surface Water Management Division, to conduct a reconnaissance of 29 major drainage basins located in King County. The effort began with an initial investigation of three basins -- Evans, Soos, and Hylebos Creeks -- in order to determine existing and potential surface water problems and to recommend action to mitigate and prevent these problems. These initial investiga- tions used available data and new field observations to examine geology, hydrology, and habitat conditions in each basin. Findings from these three basins led the King County Council to adopt Resolution 6013 in April 1936, calling for reconnaissance to be completed on the remaining 26 basins. The Basin Reconnaissance Program, which was subsequently established, is now an important ele- ment of surface water management. The goals of the program are to provide useful data with regard to 1) critical problems needing immediate solutions, 2) basin characteristics for use in the preparation of detailed basin management plans, and 3) capital costs associated with the early resolution of drainage and problems. The reconnaissance reports are intended to provide an evaluation of present drainage con- ditions in the County in order to transmit information to policymakers to aid them in developing more detailed regulatory measures and specific capital improvement plans. They are not intended to ascribe in any conclusive manner the causes of drainage or erosion P:LC 1 Lower Cedar River Basin (continued) problems; instead, they are to be used as initial surveys from which choices for subsequent detailed engineering and other professional environmental analyses may be made. Due to the limited amount of time available for the field work in each basin, the reports must be viewed as descriptive environmental narratives rather than as final engineering conclusions. Recommendations contained in each report provide a description of potential mitigative measures for each particular basin; these measures might provide maximum environmental protection through capital project construction or development approval conditions. The appropriate extent of such measures will be decided on a case-by-case basis by County offi- cials responsible for reviewing applications for permit approvals and for choosing among competing projects for public construction. Nothing in the reports is intended to substitute for a more thorough environmental and engineering analysis possible on a site-specific basis for any proposal. M. FINDINGS IN LOWER CEDAR RIVER BASIN The field reconnaissance of Lower Cedar River Basin was conducted in January 1987 by Robert R. Fuerstenberg, biologist; Br ce L. Barker. engineer: and Lee Benda, geologist. Their findings and recommendations are presented here. A Overview of Lower Cedar River Basin The lower Cedar River Basin is located in southwest King County and is 27 square miles in area. It extends southeast from the mouth of the Cedar River on Lake Washington to approximately river mile 14.0. The boundary to the northeast is marked by a ridgetop connecting the city of Renton to Webster and Franklin Lakes; the boundary to the southwest runs along Petrovitskv Road to Lake Youngs. Renton is the only incorporated area in the basin. Other population centers include Fairwood, Maplewood Heights, and Maple Valley. Except for the city of Renton, most of the residential concentrations are located on the upland plateaus overlooking the Cedar River Valley. These upland developments are recent compared to the smaller established communities on the valley floor. The basin lies within portions of three King County planning areas: Newcastle in the northeast (which includes Renton), Tahoma-Raven Heights in the east, and Soos Creek (the largest of the three) in the west. Rural areas exist on the valley floor on both sides of the Lower Cedar River, from approximately river mile 5.50 to 13.00. These are limited to pastureland for horses. cows. and some sheep and several small "u-pick" fruit and vegetable farms. Similar areas are located on the southern uplands above the reach from river mile 5.50 to 7.00 and in the Lake Desire-Otter Lake area. The plateau is also the site of sand and gravel mining operations and, in the southern uplands, of the abandoned Fire King Coal Mine. Peat deposits exist west of Like Desire and north and south of Otter Lake, and peat mining is being carried out north of Otter Lake. Present zoning allows for urban and suburban densities throughout much of the basin, particularly on the upland plateaus and in the Cedar River Valley from its mouth to appoximately river mile 6.50. Population projections for the vear 2000 in the three planninn areas containing the Lower Cedar Basin are over 311,000, an increase of 47 P:I_C 2 Lower Cedar River Basin (continued) percent from the present. Most of this growth will occur in the Soos Creek Planning Area. Dominant geological and geomorphic features. The geology of the Lower Cedar River Basin is diverse. Geological formations exposed along the valley include sedimentary rocks, undifferentiated older glacial drift, extensive ground moraine deposits, recent alluvium along the Cedar River, and landslide deposits along the river and its tribu- taries. The sedimentary rocks, composed of moderately dipping sandstones, con- glomerates, mudstones, and shales, are exposed locally along the cliffs of the Cedar River Valley near the mouth of the Cedar River. In addition, the Renton formation, composed of sandstones, mudstones, and shales with periodic deposits of coal, is also exposed along the lower portion of the Lower Cedar River Valley. Undifferentiated glacial deposits found here are composed of three or more till sheets, glacio-fluvial sand and gravel, glacio-lacustrine clay, and sand, and non-glacial sand, clay and thin peat. These lie over the sedimentary rock formations and are best exposed in cross-section along the cliffs of the main valley and major tributaries. The morphology of the Lower Cedar River Basin is dominated by the valley formed by the Cedar River. Valley walls are steep cliffs formed by landslides in glacial sedi- ments. A once extensive and meandering River, which created a wide vallev floor as it cut its way westward. the Cedar today is diked for most of its length through the lower valley. A narrow but extensive band of landslide deposits exists along the steep cliffs of the main river and its major tributaries. The landslide deposits consist of deformed blocks of glacial sediments and colluvium derived from slides or mass flowage, such as landslides and debris flows. Recent alluvial deposits fill the valley and major tributaries. Small, composite, alluvial debris fans exist at the mouths of the largest tributaries. Closed depressions, principally in the uplands, have lacustrine and peat deposits. The Lower Cedar River Valley has a high potential for erosion due to steep slopes and the existence of a clay laver that promotes soil failures. In addition, the confined nature of tributary channels between steep hillslopes promotes bank erosion during high flows. Numerous recent landslides are evident along cliffs of many of the steep tributaries and along the main stem of the Cedar River. These have been accelerated by the removal of vegetation and the routing of concentrated storm flows over steep slopes in areas where development has occurred. Hydrologic and hydraulic characteristics. The Cedar River Basin is composed of a complex drainage network consisting of the Cedar River and 17 tributaries. The larger tributaries begin in lakes or wetlands on the bluffs and flow through relatively flat. stable channels to the edge of the Cedar River Valley, then plunge down to the valley floor through steep, erodible ravines. Tributaries of this type such as Tributary 0304 (with headwaters at Wetland 3111) and Tributary 0323 (which begins at Lake Desire), are found on the south side of the Cedar River. Another type of tributary collects surface runoff from urbanized areas, pastureland, and wooded areas. Tributaries 0302, 0307, and 0312 are examples of this type of tributary. They are intermittent (depending on rainfall), shorter in length, flow through shallower channels that are steeper at the bluffs and transport more material during times of P:LC 3 Lower Cedar River Basin - (continued) high flows. Some of the worst problems located during field investigation (see Appendix C for a full listing) occur on this type of tributary. Catchments 5, 6, and 12 have very infiltrative soils. Urban developments hvae utilized R/D poinds to effectively infiltrate all urban runoff before it reaches the valley hillslopes. The infiltrated runoff then reappears as springs. Two large lakes (Desire and Otter), together with four smaller ones (Shady, Peterson, Webster, and Francis) lie in the southeast third of the basin. Numerous large wetland areas exist in this section as well. The field team identified 10 potential wetland sites that had not been previously identified in the Sensitive Areas Map Folio (SAMF). The system of lakes and wetlands in this area effectively buffers the high flows draining to these tributaries. Habitat characteristics. With few exceptions, usable fish habitat exists only in peren- nial streams (i.e., Trib. 0302, 0304, 0305, 0323, and possibly 0303). In other streams (e.g., Trib. 0303 and 0310), steep gradients preclude fish use. Steep gradients also reduce fish use in the perennial systems (except for Trib. 0323). Habitat is in various stages of degradation in these systems; pools are being filled and gravels and debris shift regularly. In Tributary 0323 (Peterson Creek), however. habitat diversity is extensive, and the channel is not seriously degraded. At this location the field team observed at least three species of salmonoids. In general, the most diverse and least disturbed habitat in a tributary system occurs in the large wetland areas in the southeast third of the basin. Usable habitat for anadromous fish is found in the low-gradient portions of streams where channels cross the Cedar River Vallev floor. In these reaches, however, only spawning habitat is likely to be available, as the pools and woody debris necessary for successful rearing either do not exist or are quite limited. Excellent spawning and rearing areas exist where pools and riffles are extensive, instream cover and bank vegetation are intact, and diversity of habitat types is abundant. B. Effects of Urbanization in the Basin Flooding, erosion, and the degradation of habitat associated with development in the Lower Cedar River Basin are most apparent where development has eliminated vege- tation along the edges of the valley and where stormwater has been routed down channels and swales. The removal of vegetation, such as trees, above and below the edges of vallev walls, as well as the discharging of stormwater over the valley wall, has resulted in tension cracks and landslides that are endangering some houses. The sedi- ments from these failures are depositing in streams and on valley floors and damaging fish habitat and private property. Discharging stormwater from increased impervious areas into steep tributary channels and swales is seriously destabilizing channels and valley walls; this in turn results in channel downcutting, bank erosion, and landslides. The sediments from these problems often degrade fish habitat and settle out on pri- vate property along the valley floor. Two serious instances of development-related erosion occurred during the November 1936 storm: 1) culverts rerouting the stream were plugged, causing the formation of a new channel that destroyed portions of roads on Tributary 0314; and 2) new, uncom- P:LC 4 Lower Cedar River Basin (continued) pacted fill adjacent to new residences near collection point 5 was washed partly away during the storm, causing landsliding and gullying. Future problems will be similar to these, as commercial and residential developments increase flow rates and volumes by decreasing natural storage and infiltration. This is expected to occur if wetlands on the upper plateau are encroached upon or lost (e.g., on Trib. 0304 at RM 2.30 and on Trib. 0304A at Rm 1.60). The preservation of wetlands and streambank vegetation and the attenuation of storm flows are essential in this basin. C. Specific Problems Identified The steep valley sideslopes through which streams pass and the often dense upland development result in a number of similar problems that repeat themselves throughout the Lower Cedar River Basin. The most significant of these are outlined and discussed below. 1. Drainage and flooding problems are often the result of several conditions: a. Undersized culverts and inadequate entrance structures. The most notable area is on Tributary 0306 at river mile .30, where a culvert here was blocked by debris carried downstream by the stream and caused erosion and flooding of Fainvood Golf Course. The blockage was compounded by the fact that the culvert was undersized: the problem will worsen as flows increase from upstream development. b. Serious instrieam erosion and subsequent downstream sedimentation. These have been caused by three main factors: 1) runoff from residential developments on the bluffs above the valley, 2) compacted pastureland due to livestock, and 3) runoff from impervious areas originating at gravel pits. These problems will continue and worsen until mitigative measures are taken. (See Appendix C for specific examples.) c. Undersized rechannelized streams. Tributaries on the vallev floor are too small to carry the increased flows originating in developed residential areas along the top of the bluffs. For example, Tributary 0302 at river mile .25, the channel along Maplewood Golf Course, overtops and floods during storms. d. Construction in wetland and floodplain areas, Manv of the wetlands on the south side of the Cedar River are peat bogs, and roads built through them continue to settle each year, increasing the amount of flooding on the road. For example, the road crossing with Tributary 0328B north of Lake Desire will experience more severe flooding as the road settles. e. Discharging of stormwater at the top of steep banks. At river mile 2.20 on the Cedar River, a trailer park (constructed on the edge of the cliff) discharges its drainage down the vallev wall. Increased flows erode the steep valley, depositing sediments on the valley floor, blocking channels and causing flooding. These problems will eventually stabilize, but only after a large quantity of soil has been eroded. P:LC 5 Lower Cedar River Basin (continued) 2 Damage to property is being caused by three factors: a. Landslides and potential landslides. Landslides are accelerated by the removal of vegetation on steep slopes in preparation for residential construction and/or by the routing of storm flows over hillslopes. For example, a large landslide has already occurred in the front yard of a resi- dence on the Cedar River at river mile 7.80. b. Sedimentation (from landslides). Sedimentation and channel and bank ero- sion are damaging private property along the valley floor (Trib. 0299 and 0310). C. Flooding during storms. Flooding has been brought on by the effects of development and associated changes to the natural drainage systems in the basin. (See "B" above.) 3. Destruction of habitat is being caused by four conditions: a. Sedimentation of pools and riffles and cementing of gravels. These problems, the result of severe erosion and the transport of bedload material, have been caused by upland developments in the basin and the presence of associated impervious surfaces, which increase the rate and quantity of surface runoff. Sedimentation and cementing of gravels in streambeds destroy natural spawning and rearing habitat. On Tributary_ 0307 at river mile .40 and Tributary 0305 at river miles .95, 1.20, and 1.70, recent high flows have eroded the streambed at least one foot, contributing to a serious siltation problem downstream. :.Heavy bedload transport is evi- dent in all systems of the basin except Tributary 0323. In Tributary 0303 at river mile .25. fine sediments are accumulating in gravels that may be used by resident fish. In Tributary 0304 between river miles .95 and 1.20, pools are being filled by sands and gravels and rearing habitat is being rapidly lost. b. Channetization of stream beds. Loss of habitat through channelization has occurred in all the major streams of the basin, but most noticeably in those reaches that cross the vallev floor. These reaches lack habitat diversity, reducing fish use for spawning and rearing. Channelization has damaged or destroved habitat in several reaches that were once heavily used by fish, these include Tributary 0302 between river mile .30 and 40, Tributary 0304 between river miles .05 and .13, Tributary 0305 between river mile .20 and .75. and Tributary 0323 from river mile 1.10 to 1.40. These systems cannot afford a further reduction of habitat and still remain viable fishery resour- ces. C. "1'he accumulation of trash in stream beds. This problem occurs in close proximity to residential areas. Trash degrades water quality and is visually unpleasant. Tires, appliances, furniture, and other trash have been thrown into Tributary 0302 at river miles 1.00 and 1.10 and in Tributary 0303 at river mile .35. P:LC 6 Lower Cedar River Basin (continued) d. Wetland encroachment_ Encroachment destroys habitat and eliminates natural water filtration and storage for surface runoff. Examples of this problem were observed on Tributary 0304 at river mile 2.30, Tributary 0308 at .80, and Tributary 0304A at river mile 1.80. Many wetlands have already been completely lost through filling, for example on Tributary 0306A at river mile .55. Suspected violations were forwarded to Building and Land Development for enforcement. IV_ RECOMMENDATIONS FOR ACTION The primary recommendations for action in the Lower Cedar River Basin addresses current severe problems related to erosion, habitat destruction, and flooding. Prevention of these problems will be accomplished by controlling locations and densities of new development and providing adequate R/D facilities for stormwater. A_ Reduce landslide hazards by: 1. Including sensitive areas not previously mapped on the Sensitive Areas Map Folio (SAME). See Appendix C for a full listing of sensitive areas. 2 Establishing building setbacks along cliffs and native growth protection easements along steep ravines. 3. Discouraging or eliminating the routing of stormwater over cliffs, unless adequate tightline systems can be constructed to convey flows in a safe, nonerosive manner to the bottom of cliffs. 4. Decreasing peak flows by constructing larger R/D facilities to lessen the landslide and erosion occurrence along tributary slopes. B. Reduce erosion and flooding in the basin by improving surface water management: 1. Direct the Facilities Management Section of the Surface Water Management Division to evaluate existing storm-detention and conveyance facilities to deter- mine whether they are properly sized to meet current standards. Evaluation should begin with all single-orifice R/D facilities. 2. Consider areas other than wetlands as regional storm-detention facilities. Tributary 0300 at river mile .42 is the site for a proposed dam, for example. 3. Utilize existing lower quality wetlands (those rated other than #1) as regional storm-detention facilities. Wetlands 3102 and 3142 could provide more live storage, for example. 4. Review channel and culvert capacity for conveying existing and future runoff, and establish floodplain areas in regions of slight gradient for existing and future runoff conditions. 5. Promote the infiltration of surface water through the use of retention facilities and open channels instead of pipes where the soil and slope conditions permit. Collection points 5. 6. and 12 on plateaus have such soil conditions. P:LC 7 Lower Cedar River Basin (continued) C- Prevent future problems of erosion and flooding with appropriate analysis, planning, and policy development related to surface water management: 1. Conduct a detailed, comprehensive hydraulic/hydrologic analysis of any proposed developments to determine impacts on the drainage courses downstream. This is especially critical for areas on the upper bluffs and plateau, which drain over steep, sensitive banks above the Cedar River. 2. Conduct a study of the impact of locating infiltration ponds utilized near the edge of the bluffs to determine their effect on seepage faces on the lower face of the bluffs. This might be accomplished with a computer-based numerical model of the groundwater flow. 3. Require the tighttining of storm drainage down steep or sensitive slopes when they cannot be directed away from the slopes. This is done by piping the flow down the slope and discharging it at the bottom with adequate energy dissipation. Manv of the intermittent tributaries flowing down the banks should be tightlined as urban development increases flow to them. 4. Construct new R/D ponds with filter berms to improve water quality and reduce fine sediment loads. New R/D ponds should have two cells with gravel-berm filters and vegetated swales at the inlet and outlet. Consider Tributaries 0304, 0304A, 0302, and 0303 as sites for this type of facility in order enhance water quality. 5. Maintain natural vegetation on streambanks and floodplains. This is especially important for relatively flat channels flowing on the plateau before they reach the steep bluffs because these channels and their floodplains will attenuate flows during times of heavy runoff. 6. Maintain buffer areas around wetlands. Many of the tributaries on the south side of the Cedar River headwater at wetlands. These wetlands act as natural storage areas during storms. 7. Reevaluate King County policy regarding permitting for gravel mining on steep, sensitive slopes. 8. Include the city of Rention in future intcrlocal agreements for planning and capi- tal improvement projects where city and county interests overlap. D. Eliminate present damage to habitat and prevent future damage by addressing specific problems in the stream systems. The following activities should be coordinated among King County, the Muckleshoot Indian Tribe. and State Departments of Fisheries and Game: 1. Reduce damaging storm flows with greater detention volume and lower release rates at upstream developments. 2. Implement restoration projects on Tributaries 0304 (river mile .00-.20), Tributary 0305 (river mile .20-.30), Tributary 0303 (river mile .25- ;5), and Tributary 0328 (river mile 1.10 -1.40): I':LC 8 Lower Cedar River Basin (continued) a. On Tri-butary 0304: Clean streambed gravels, add habitat and bed-control weirs, and plant bank vegetation for shade. b. On Tributary 0305: Construct a new channel and move stream from road- side channel to its new location on adjacent lands. Implement a full restoration project to provide channel meanders, habitat structures, pool/riffle enhancement, streambed gravel replacement, and revegetation. C. On Tributary 0303: Move stream from present channel to a location further north, away from the roadside. If relocation is not possible, these minimum steps should be taken: Add habitat structure to existing channel with root masses, deflectors, boulder clusters, and other features; revegetate channel banks with shrubs and small trees; enhance stream crossings with bottomless pipe arches. d. On Tributary 0328 (Peterson Creek): Add habitat structure by replacing the straight, shortened channel with a more natural, meandering one; place habitat structures (such as root masses, deflectors, cover logs and boulder clusters) throughout the channel; and revegetate banks with shrubs common to adjacent riparian zones (salmonberry, ninebark, or dogwood, for example). 3. Protect the Peterson Creek system (Trio. 0328) in its present, near-pristine state. This will include not only the restoration outlined in section A above, but also the adoption of land use management regulations to prevent future habitat destruction: a. Protect all existing wetlands within the subcatchments of Peterson Creek. Employ wetland buffers at least 100 feet wide without exception. b. Restrict development in the critical headwater area (drainage, habitat, water quality) bounded by Lake Desire, Otter Lake, and Peterson Lake to rural densities. C. Designate and protect storea aside management zones of at least 100 feet from the ordinary high-water mark (OHWM) along the main stem of the creek. Use 25 feet from the OHWM on tributaries. d. Preserve floodplains and their forests for dynamic retention of sediments and water. C. Restrict vegetation removal in streamside/wetland management zones. f. Size RID facilities to store the 100-year storm at a two-to-five-year release rate. Use the two-cell type of pond with a forebav, a gravel filter, and a vegetated swale outflow where feasible. g. Regulate more closely all septic tank and drain-field installations as well as maintenance schedules, particularly in the Lake Desire, Otter Lake, and Peterson Lake drainage areas. P:LC 9 Lower Cedar River Basin (continued) h. Work with the State Department of Ecology to establish minimum stream- flow requirements for Peterson Creek and Lake Desire tributary. 4. Develop and promote public education and involvement programs for basin awareness. Work with schools, environmental groups, and the civic and business communities to conduct educational and restoration programs. P:LC 10 LOWER CEDAR RIVER BASIN Basin Boundary Subcatchment Boundary Collection Point ec ion (� n, --�/ AL Stream i 0299 Tributary Number 103115 Proposed Project � 3 Iw AT 0 1 2 Miles rn' 1 .. a a. Jul ;I Y,1987 Al �. 1 1 \ 1� K 26 „ r . e 3109 °w° o o �,) o m w 117 w a 3 ' 1 p I , M22 1 b 03� i ,. 3116 p32�� --- t 21 f „ ow 3115 CIO g ! LE WATERSH 12 -" K,• 31 to 1 v,.:.. )y��xr, .., y �__.: ..a Ma le Wlley i .I i I - I APPENDIX A ESTIMATED COSTS: PROPOSED CAPITAL, IMPROVEMENT PRO.IECI'S LOWER CEDAR CREEK BASIN Indicates project was identified by Surface Water Management office prior to reconnaissance. NOTE: All projects are located on map included in this report. Project Collect. Estimated Costs Number Point Project Description Problem Addressed and Comments 3105" 10 Enhance 2200' of Trib. 0305 from Mitigates flooding of King $115,000 Cedar River to Elliot Bridge. County park land. (NOTE: This project was proposed by Surface Water Management, is in the design phase, and will be constructed by 1989.) 3109" 10 Secure casements to wetland located Better utilizes wetland's storage $186,000 in Cascade Park and construct a berm capacity to nddress peak flows from at the outlet. Replace existing surrounding urban area. catch basins with control structures. Project should be justified by a basin studv. Wetland rated #2. (This wetland will require further biological evaluation before R/D design and construction.) P:LC.APA A_1 Project Collect. Estimated Costs Number Point Pro'cct Description Problem Addressed and Comments 3111 Secure easements to outlet to Francis Will provide additional storage $175,000 (Wetland 1_.ake and 1100' of channel from lake to mitigate anticipated future 31 3G o p' to SE 194th St. Construct a weir to increased flows. raise lake level 1', and enhance 1100' of Trib. 0317. Should be justified by a basin plan. Wetland rated #1. (This wetland will require further biological evaluation before R/D design and construction.) 3112 19 Secure casement for outlet to wetland Will provide additional storage $117,000 (Wetland and replace existing weir with a for anticipated future peak flows. 3142) concrete-slotted weir. Should be justified by a basin plan. Wetland rated #2. ('Phis wetland will require further biological evaluation before R/D design and construction. 31 14° Secure casement to Wetland 3150 and Addresses anticipated increases in $134 000 (Wetland construct a containment berm and flow caused by development. 3150) control structure at the outlet. Project should be justified by a basin plan. Wetland rated #2. ('Phis wetland will require further hiologieal evaluation before R/D design and construciton.) 3115 13 Install detention pond and 1.000' Mitigates severe erosion and $361,000 of tightlinc. Project is indcpcn- flooding during times of high dently justifiable. flows. I1:1.C.AI'A A-2 Project Collect. Estimated Costs Number Point Project Description Problem Addressed and Comments 3116 21 Raise existing road embankment Mitigates seasonal flooding of Iake $73,000 24'. Project should be indepen- Desire Dr. SE caused by road bed dently justifiable (Refer to settling in the peat bog. Roads Division.) 3117 16 Install 1,400' of tightline, a Mitigates severe erosion, sediments $501,000 sediment trap, and 700' of channel deposited on County roads, and from Jones Rd. to Cedar River. flooding during times of high Project is independently justi- flows. fiable. ills 10 Install 300' of 36" culvert, a new Will prevent blockage of culvert $87,000 inlet structure, manhole, and catch and the accompanying flooding and basin. Project is independently erosion of hairwood Golf Course and justifiable. mobile home park below. 3119 4 Construct a detention dam and Project location is ideal Because $159,000 control structure in a deep it addressers flows from a large channelized section of Trib. residential area before they reach 0300. Project is independently the steep, sensitive area next to justifiable. the Cedar River. 3120 15 Construct a sedimentation pond and Mitigates flooding of residence and $163,000 1,000' of channel from .Tones Rd. to sediment deposition on Jones Rd. Cedar River. Project is indepen- dently justifiable P:LC.APA A-3 Project Collcet. Estimated Costs Number Point Project Description Problem Addressed and Comments 3121 7 Sccure casement to wetland and con- Addresses increased flows in Trib. $371.000 (Wetland struct a containment berm and concrete 0304 and 0304A from residential 3102) weir at outlet. Project should be developments. justified by a basin plan. Wetland rated #2. Biological assessment is needed to assure that this project does not decrease habitat values. 3122 11 Purchase existing ponds on Pairwood Mitigates flooding and erosion $342,000 Golf Course and expand to provide downstream. greater flow detention. Project is independently justifiable. P:LC.APA A-4 APPENDIX B CAPITAL IMPROVEMENT PROJECT RANKING LOWER CEDAR RIVER BASIN Prior to the Lower Cedar River Basin field reconnaissance, 12 projects had been identified and rated using the CIP selection criteria developed by the Surface Water Management (SWM) and Natural Resources and Parks Divisions. Following the reconnaissance, 13 projects remain proposed for this area. They include eight new, previously unidentified and unrated projects. These displace seven previously selected projects, which were eliminated based on the consensus of the recon- naissance team. Projects were eliminated for several reasons: two sites were annexed by the city of Renton, two projects were found to be unnecessary, two sites were categorized as #1 wetlands (and are*ineligible), and one project was determined to be infeasible. The previous SWM capital improvement project list for the Lower Cedar River Basin had an esti- mated cost of $2,710,000, while the revised list increases to an estimated cost of S2,784,000. This 3 percent increase in estimated capital costs is due to the addition of projects after the reconnaissance. The following table summarizes the scores and costs for the CIPs proposed for the Lower Cedar River Basin. These projects were rated according to previously established SWM Program Citizen Advisory Committee criteria. The projects ranked below are those for which the first rating question, ELEMENT 1: "GO/NO GO," could be answered affirmatively. Projects with scores of 100 or higher can be considered now for merging into the "live" CIP list. RANK PROJECT NO. SCORE COST 1 3122 103 $342,000 2 3118 90 87,000 3 3120 75 163,000 4 3109* 67 186,000 5 3121 65 371,000 6 3117 60 501,000 7 3115 60 361,000 8 3116 55 73,000 9 3114* 28 134,000 10 3111* 25 175,000 11 3112* 17 117,000 12 3119* 15 159.000 13 3105 12 115.000 TOTAL $2,784,000 * Projects proposed prior to the Reconnaissance Program P:LC.APB B-1 APPENDIX C DETAILED FINDINGS AND RECOMMENDATIONS LOWER CEDAR RIVER BASIN ° All items listed here are located on final display maps in the offices of Surface Water Management, Building and Land Development and Basin Planning. Trib. & Collect. Existing Anticipated Item° River Mile Point Category Prop. Proj. Conditions and Problems Conditions and Problems Recommendations 1 -- 5 Geology Gullying and landslides in Continued erosion. Recompact fill, revegetate, uncompacted fill in new and drain adequately. development near edge of steep hillslope. 2 -- 14 Geology Small landslide has formed None (natural failure). None. debris flow (11/86). Sedimentation in yard of residence. 3 0299 4 Geology Landslides in sedimentary Natural failure. None. RM 2.6 rock in cutbanks adjacent to railroad. 4 0299 16 Geology Drainage from residential Increasing erosion. Provide adequate R/D to RM 9.65 area is resulting in attenuate flows. gullying in Swale. P: LC.APC C-1 Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Prom. Conditions and Problems Conditions and Problems Recommendations 5 0299 13 Geology Horse farm in uplands has Continued high erosion and Develop R/D at horse farm RM 12.1 created extensive imper- sedimentation. to attenuate peak flows. vious surfaces, resulting See Project 3115. in channel scour, bank erosion, landslides, and sedimentation at mouth of basin. Residence overcome with sediment. G -- 13 Geology Landslide terrain for sale Site of future mass erosion. Prohibit development here. by realtors. High risk for Notify Building and Land landslides, flooding (from Development. Add area to springs). SAMF. 7 - 7 Geology Large-scale landsides Natural process. None. adjacent to Cedar River due to springs and cutting of toeslopes by streams. Appears to be natural. 4 -- 2 Geology Gullying in valley wall, Unknown. None. possibly from natural springs. 9 -- 14 Geology Landslide debris flow from Existing tension cracks Revegetate hillslope with residence on SE 147th Pl., indicate future instability. trees and shrubs. Renton. P: LC.APC C-2 i Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proi. Conditions and Problems Conditions and Problems Recommendations 10 0299.1A 21 Hydrology 3116 Frequent flooding of Road located on top of peat Elevate the road 34' by RM .08 county road caused by low bog and will continue to filling on top of the road embankment. settle, aggravating flooding present road embankment. problem. Also stabilize embankment. 11 0300 4 Geology Extensive channel and Problems will continue. Provide adequate R/D in . RM .00-.40 bank erosion and numerous uplands. (See Project landslides due to 3119.) development-related stormwater. 12 0300 4 Hydrology 3119 Development-related peak Increased erosion on Construct detention dam in flows have caused sig- hillslopes below. deep, channelized reach of nificant bank erosion. Trib. 0300. 13 0300 4 Hydrology 3109 Collection point 4 has Degradation of Trib. 0300 Construct berm and standard RM 1.40 been nearly completely from RM .42 downstream. This control structure at outlet urbanized. section is very steep and to Wetland 3120 in Cascade susceptible to erosion. Park. 14 0302 6 Geology Channel downcutting and Will continue at same level Control storm flows from RM .50 bank erosion. or increase. uplands. 15 0302 6 Geology Bank erosion (medium den- Increasing erosion with Provide adequate R/D in RM .80-1.00 sity) at meanders and increasing flow from devel- uplands as area develops. obstructions. opments. P: LC.APC C-3 Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proi. Conditions and Problems Conditions and Problems Recommendations 16 0302 6 Geology Gully erosion from broken None. Culvert has been None. culverts. repaired. 17 0302 6 Geology Severe gully erosion Continued erosion. Tightline flows to RM .60-.80 creating small valleys main stem. from daylight culverts. 18 0302 6 Habitat Stream channeled along While fish now use this Add habitat diversity RM.35 golf course road. No reach, lack of habitat will (e.g., structures, overhead overhead cover. No habi- eventually reduce popula- vegetation). Gain tat diversity. tions. easement to restore mean- ders, if possible. 19 0302 6 Ilydrology Tributary drains down Problem will worsen as Construct detention dam RM .45 steep bluffs on north development upstream upstream of golf course. side of Cedar River, continues. carrying debris and flooding Maplewood Golf Course. 20 0302 6 Habitat Water supply dam. Full As impoundment fills, storm- Dredge pond and maintain RM .50 barier to upstream water will flood over bank. it as sediment catch. migration. Impoundment Structure may fail. is filling with sediment. 21 0302 6 Habitat Severe gullying from right Will continue to erode until - Tightline downslope. RM .90 bank corregated metal reaches till layer. - Add velocity attenuator at pipe. Heavy sediment stream. delivery to stream. P: LC.APC C-4 Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proj. Conditions and Problems Conditions and Problems Recommendations 22 0302 6 Habitat Trash in stream (auto, Area adjacent to corridor, - Remove trash. RM 1.00 tires, appliances). will continue to collect - Distribute educational trash and debris. Further materials to streamside worsening of water quality, residents. sedimentation, erosion. - Cite violators, if problem persists. 23 0302 6 Habitat Trash in stream. Water Area adjacent to corridor, - Remove trash. RM 1.10 quality problem, will continue to collect - Distribute educational unsightly. trash and debris. Further materials to streamside worsening of water quality. residents. Cite violators, if problem persists. 24 0303 6 Geology Extensive bank erosion in None. Increase R/D volumes, slow release; upper portions of tribu- rate to nonerosive levels. tary. 25 0303 6 Habitat Habitat suitable for resi- Sediments will eventually - Control stormwater volumes RM .25 dent fish. Sediment accu- cover gravels. Habitat and discharge rates from mulating. will become unsuitable for developments. fish use. - Manually clean gravels when necessary. 26 0303 6 Habitat Trash and litter in Further decreases in water - Remove trash and litter. RM .35 channel affecting water quality. - Distribute educational materials quality, causing erosion. to streamside residents. - Cite violators, if problem persists. P: L(:.APC C-5 Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proi. Conditions and Problems Conditions and Problems Recommendations 27 0304 7 Habitat Landslides contributing Sediment will continue to Maintain riparian corridor RM .40 sediment to channel. Heavy enter system until landslide with setbacks at least 50' deposition in pools, at stabilizes. from tops of banks. obstructions, even in riffles. 24 0304 4 Habitat Horses have access to Further decreases in water - Encourage residents to fence RM 2.10 stream, causing some bank quality, bank erosion likely. channel back 15' from ordinary deterioration and possibly high-water mark. affecting water quality. - Limit access to livestock to one or two points along stream. 29 0304 3 Hydrology Flooding caused by failing Problem will continue until - Problem referred to Main- RM 2.30 R/D at 176th St. & 146th outlet structure is tenance section of Surface Ave SE. modified. Water Management Division. 30 0304 4 Habitat Encroachment occurring Wetland likely to be - Require encroaching fills RM 2.40 along all boundaries of reduced slowly until it is to be removed. this headwater wetland. completely destroyed. Loss - Establish specific buffer of storage, filtration, around this wetland. organic production, and - Enforce sensitive areas wildlife habitat. ordinances and regula- tions. 31 0304 7 Geology Several gullies due to Problem will continue. - Tightline drainage. RM .80 daylight culverts; a few have recent landslides. P: LC.APC C-6 Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proi. Conditions and Problems Conditions and Problems Recommendations 32 0304 7 Habitat Extensive riffle (to RM Gravels risk becoming - Enhance habitat by addi- RM .00 .15. Creek channeled. No cemented. Few resting areas tion of woody debris in woody debris, little bank for upstream migrating fish. stream. vegetation. Steelhead, - Revegetate bank. coho spawners here. - Enhance pool/riffle ratio. 33 0304 7 Habitat Debris jam may be a Debris will continue to - Selectively remove debris RM .20 partial migration barrier. accumulate. Channel will to allow fish passage. likely divert or jam will - Stabilize large woody fail, releasing accumulated debris. sediment. 34 0304 7 Habitat Debris jam. Bed drops 3' Debris will continue to - Selectively remove debris RM .62 over jam and sediment, accumulate. Channel will to allow fish passage. forming anadromous likely divert or jam will - Stabilize large woody barrier. fail, releasing accumulated debris. sediment. 36 0304 7 Habitat Water turbid; oily sheen Water quality will continue - Educate residents about RM .40 and odor present. Storm to decline as runoff and how to maintain water quality. drains empty directly into waste enter stream. - Mark storm drains with stream. "Dump no oil" signs. - Emphasize recycling of oil. 37 0304A 7 hydrology 3102 Existing forested wetland Additional storage could be Construct a proportional weir RM 1.30 provides detention for utilized by constructing and berm at wetland outlet. Trib. 0304A and 0304 in berm and weir at outlet. Project could be used instead heavily developed area. This could be done to atten- of Project 3107 to rpeserve the uate increased peak flows #1 rated wetland (where project as upstream area develops. would be built). P: LC.APC C-7 Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proj. Conditions and Problems Conditions and Problems Recommendations 38 0304A 18 I-lydrology 3115 Runoff generated on top of Flooding will continue as - Construct detention pond RM .40 bluffs on southwest side long as land use remains the at top of bluffs. of Cedar River is causing same on top of bluffs or - Tightline drainage down severe bank erosion, until mitigating measures bluffs, then channelize it flooding and debris flows are taken. Runoff origin- to an existing ditch onto several residences ates from highly compacted alongside SR 169. of valley floor. pastureland on uplands. - Prevent similar problems elsewhere with land use regulations, including provisions for preservation of vegetation buffers near tops of cliffs. 39 0305 10 Geology Extensive bank erosion, Susceptible to increases Attenuate high flows. partly due to subsurface with increasing storm flow. clay layer and landslide topography. 40 0305 10 Geology Local severe bank Problem will continue. Existing rock-filled RM 1.10 erosion. gabions are deflecting flow. 41 0305 10 Geology Extensive channel down- Continued erosion. Attenuate high flows with RM 2.10- cutting and bank erosion. adequate R/D. (R/D 1.75 currently exists.) 42 0305 10 Geology Several gullies and also- Erosion will continue. Tightline culverts. RM 2.15- ciated landslides due to 1.75 daylight culverts on steep slopes adjacent to chan- nels. P: LC.APC C-8 Trio. & Collcct. Existing Anticipated Itcm Rivcr Mile Point Category Prop. Proj. Conditions and Problems Conditions and Problems Recommendations 43 0305 10 Ilabitat Madsen Creek in ditch along Potential for fuel entry in- Acquire 30' easement away RM .20 SE Jones Rd. Heavy silt; to creek. Further decreases from roadside. Construct road runoff; water quality in water quality can be ex- new stream channel. adversely affected. pected. 44 0305 10 IIabitat Creek in ditch along south Further decreases in water Acquire 30' easement away RM .35 side of SR 169. Heavy quality can be expected. from roadside. Construct inputs of oils, anti- Potential for autos to enter new stream channel. freezes, heavy metals, channel. Lack of habitat. organic pollutants likely. Sand, silt from roadside (of SR 169) enters also. 45 0305 ItM .00- 10 hydrology 3105 Section of Trib. 0305, Flooding will continue. Construct and enhance 2200' of .40 RM .00-.40 is experiencing (See Appendix A, Project channel through undeveloped extensive flooding. 3105.) King County Park Land. 46 0305 10 Habitat Channelized along dri- Further siltation, water Acquire easement; move RM .50 veway; lacks habitat quality degradation can be creek from driveway diversity. Driveway scdi- anticipated. Lack of habitat 10-15'. Add meanders and ments enter channel, and precludes optimum salmonid habitat structures to oil, placed on driveway use. increase diversity. enters stream. 47 0305 10 Habitat Channelized tributary Little salmonid use Add structures to increase RM .65 lacks habitat diversity, anticipated. Spawning and diversity in stream. cover for salmonids. rearing success limited Manually clean. gravels by Gravels compacted. (unless reach is restored). churning them. P: LC.APC C-9 Trib. & Collcct. Existing Anticipated Item River Mile Point Category Prop. Proi. Conditions and Problems Conditions and Problems Recommendations 44 0305 10 IIabitat Good spawning riffles occur Increased flows may cause Control flows into system RM .90 here. ►/z-3" gravels, few gravcl bar movement. from developed areas fines, not compact. High Suitable gravels may be upstream. If necessary, flows are moving material, transported downstream to add bed controls to hold however. unusable areas for spawning gravels or "vee" struc- salmonids. tures to recruit them. 49 0305 10 1labitat Severe bank cutting and Further erosion/scouring can Control high flows by RM .95 erosion occurs here. Bed be expected. Channel increasing upper basin R/D scouring evident. Reach deterioration will continue. facilities, lowering subject to high, rapid Flows appear to be generated discharge rates to stream. flows. at developments. 50 0305 10 Habitat Much woody debris Debris jams will occur with Control upstream. flows RM 1.20 movement and numerous greater frequency as flows with greater R/D volume, debris jams. Reach is increase. Sediments will lower discharge rates. subject to high, rapid build up and channel will Selectively remove debris. f lows. d ive rt. 51 0305 10 Habitat Channel erosion, bank Further channel deteriora- - Increase R/D capacity. RM 1.70 failures, downcutting oc- tion may be expected. Silt, - Decrease discharge rates. curring. Reach subject to sand transport to mainstem high, rapid flows. will increase. 52 0306 10 Geology Failure of manhole during Not applicable. Repair manhole. RM .40 11/36 storm has resulted in gully erosion. P: LC.APC C-10 Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proi. Conditions and Problems Conditions and Problems Recommendations 53 0306 10 Geology Channel downcutting, bank Erosion will increase. Clay Further increase in runoff RM .20 erosion and several layer in valley makes area should be attenuated; this landslides, due both from sensitive to landslides. is a sensitive channel. increased storm flows and development along edge. 54 0306 10 Geology Undersized culvert in arti- Possible fill failure: Lake Enlarge the corregated RM .30 ficial fill in golf course ponded behind culvert in metal pipe and/or threatens to build lake and in 1931 and threatened construct adequate trash possibly overtop bank. the fill. rack. Breach flood possible. 55 0306 11 1labitat Channel subject to high, Further channel damage can Increase R/D capacity, RM .25 damaging flows. Erosion be expected. Sediment decrease discharge rate. evident. transport downstream will continue. 56 0306 10 Geology Downcutting, bank erosion Will continue or increase in Attenuate storm flows. RM .30-.45 and landslides. future. 57 0306 Iydrology 3113 Trib. 0306 connects with Problem will worsen as - Replace existing pipes RM .30 large tributary at manhole development upstream with larger diameter pipes here. Debris from 0306 continues. (if downstream analysis clogs this manhole, causing allows for increased flows). severe erosion of Fairwood - Install new inlet struc- Golf Course. tures with trash racks. 58 0306A 11 Hydrology 3122 Existing small ponds on Area upstream is developing - Acquire easements for ponds RM 1.30 0306A are overtopped and quickly, thus worsening the and additional area around ponds receive considerable silt problem. and construct detention pond. during high flows. The - Location is ideal for addressomg ponds are located on peak flows before they reach Fairwood Golf Course. the sensitive Cedar Reiver bluffs. I': I_.C.APC C-1 I Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proi. Conditions and Problems Conditions and Problems Recommendations 59 0306A 11 Habitat Some usable habitat exists Further habitat deterioration - Increase R/D capacities. RM .25 for resident salmonids. likely. Channel erosion will - Decrease discharge rates. Water quality is poor. increase. - Encourage use of 2-cell Channel subject to high detention ponds, swales. flows. - Prohibit filling of existing wetlands, ponds in upper basin. 60 0307 12 Geology Extensive bank erosion at Increased erosion will - Mitigate development- RM .10-.40 all meanders and obstruc- result with increased flows. related high flows. tions (trees, cars) due - Provide adequate R/D. to increased flows from development. 61 0307 12 Geology Stream eroding toes of Increasing erosion with - Mitigate development RM .10-.60 slopes resulting in increasing flows. related high flows. landslide failures. - Provide adequate R/D. 62 0307 12 IIabitat Stream channel pushed to Erosion will worsen as - Increase R/D capacity at RM .30 one side of ravine for stream flows increase. all delivery points. roadway. High energy May threaten road bank at - Reduce release rate below system. Much bank cutting, toe of slope. channel scour level. sediment transport, debris movement. 63 0307 13 Hydrology Area on top of bluffs near Infiltration sites should Construct retention faci- RM .60 Trib. 0307 has excellent be used whenever possible. lities for new develop- infiltrative capacity. These would provide ground- ments in area at these sites. water recharge. P: LC.APC C-12 Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proi. Conditions and Problems Conditions and Problems Recommendations 64 0309 15 Habitat Subject to heavy, rapid Erosion, deposition will - Control storm flows RM .10 flows. Channel erosion, increase. Sediments will upstream. deposition bars migration. migrate downstream, creating - Control volume and discharge a water quality problem. rates. 65 0310 15 Geology Sedimentation upstream from Continued sedimentation. - See "Hydrologic and hydraulic RM .60 culvert due to debris and characteristics" section in undersized culvert. New this report. corregated metal pipe con- tinues to pass water through. 66 0310 15 Geology Severe erosion below Continued erosion and - Install energy dissipator RM .05 culvert, severe sedimen- sedimentation. below corregated metal pipe. tation in residence yard. - Excavate channel through yard where original channel was located. 67 0310 15 Geology Road drainage forming gully Continued erosion. Reroute drainage. Refer problem RM 1.50 adjacent to road; road bed to Roads Maintenance. in danger. 63 0310 15 IIabitat 3120 Corregated metal pipe is Problem will continue. Reinstall corregated metal RM .25 anadromous barrier. pipe at or below bed level. P: 1-C.AI1C C-13 Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proi. Conditions and Problems Conditions and Problems Recommendations 69 0310 15 1lydrology 3120 Existing channel draining Frequency and severity of Construct detention pond RM .40 off bluffs on north side problem will worsen as on upstream side of Jones of Cedar River, causing development on bluffs Rd. to trap sediments, and flooding of residences and increases. enhance 1,000' of creek debris flows onto .Tones Rd. from Jones Rd. to Cedar during peak flows. River. 70 0310 15 Habitat Corregatcd metal pipe Problems will continue and Remove new and old pipes; RM .60 outlet approximately worsen as outfall velocities replace at lower level 9' above bed level. will scour bed and banks. with oversized pipe with Complete barrier to fish. Upstream has recent (11/86) trash rack. Old culverts at bed level deposition up to 4' deep. are plugged. 71 0311 13 Geology Gully erosion in drainage Continued accelerated ero- If possible, enlarge R/D RM 1.70 Swale due to outflow of sion. prior to its outlet in the wetland that partly seems wetland. to act as an R/D facility. 72 0314A 16 Ilvdrology 3117 Severe erosion, flooding, Problem will be aggravated - Tightline drainage between RM .20 damage to County and as area above develops. detention ponds in gravel pit. private roads from - Construct detention pond increased runoff from next to Jones Rd. to trap gravel pit operations on sediments. hillside. - Construct channel from Jones Rd. to Cedar River. 73 0314A/ 16 Geology Inadequate R/D, plugged Not applicable. See hydrology comment 0314B culvert caused by exten- above. RM .10-.40 sive channel and bank erosion and landslides. Water has cut a new channel. P: LC.APC C-14 Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proi. Conditions and Problems Conditions and Problems Recommendations 74 0317 Hydrology 3111 Francis Lake is only Trib. 0317 flows through - Construct proportional RM 1.60 hydraulic control for steep area downstream of weir at outlet. Trib. 0317. lake. If area around Francis - Enhance 1,100' from Lake develops, increased Francis Lake to SE 134th St. peak flows could cause severe damage to Trib. 0317 in the steep region. 75 0320 Hydrology 3114 Existing forested wetland If surrounding area urban- Construct containment berm RM 2.40 with large amount of un- izes, this would be a good and control structure at utilized storage. Wetland site to attenuate peak outlet of wetland (if bio- currently detains flows on flows. logical analysis permits). Trib. 0320. 76 0318 19 Habitat Salmonid parr in many Decrease in water quality Establish and maintain RM .10 pools. Large pools tip to with increasing develop- adequate buffers, 100' 1.75' deep. Some deposi- ment. Loss of habitat. from ordinary high-water tion in pools, behind Decrease in fish use. mark or 25' from top Co obstructions. slope break, whichever is greater. 77 0352 19 Habitat Salmonid use apparent from System is mostly in natural - Maintain adequate stream RM .35 carcasses. Sockeye, condition. As development corridor buffers. Chinook spawners. Some increases, higher flows and - Reduce discharge rates to sedimentation occurring. worse water quality can be pre-development levels. expected. Prevent clearing, grading within buffers. P: LC.APC C-15 Trib. & Collect. Existing Anticipated Item River Mile Point Category Prop. Proi. Conditions and Problems Conditions and Problems Recommendations 78 0329 19 Geology Medium-density landslides None. Limit development in the lZM .50 and high-density bank basin. erosion occurring due to natural causes. This indi- cates channel and valley sensitive to effects of development. (Sensitivity due to clay layer. Basin hosts some of best fish habitat in upper reaches.) 79 0328 19 Habitat Significant salmonid use Sedimentation from upstream Maintain leave strips RM .70 throughout. Sockeye reach possible. Adjacent adjacent to stream at spawners, carcasses present. development will likely least 100' from ordinary Coho, steelhead parr in reduce diversity and quality high-water mark. Restrict pools. Excellent habitat of habitat. use/development within this for spawning and rearing streamside management zone. (a redd site). Much diversity -- most exemplary in basin. Channelized reach. Uniform May cause thermal problems Restore stream habitat 40 0324 19 Habitat channel, no habitat diver- as water temperatures rise. throughout: add structure, RM 1.10 sity. Heavy sand deposition. No useful habitat. diversity, bank vegetation, 1.40 Little overhead canopy or and canopy. Cost should be bank vegetation. borne by party(ies) who channelized this reach. 81 0324 19 Hydrology 3112 Lake Peterson is small, Lake provides good peak flow Replace weir at outlet RM 1.40 open-water wetland with a attenuation and will become with a higher weir in weir at outlet. more important as upstream order to gain additional tributary area develops. storage. P: LC.APC C-16 EXHIBIT G WETLAND INVENTORY MAP EXHIBIT H DRAINAGE COMPLAINTS FROM:KING CO. DEPT.NR WLRD TO: 20G25le?82 S206 JUL 9, 1997 10:45AM P.02 NEW COMPLN TY PROBLEM TYPE OF TH BR NUMBER PE ADDRESS PROBLEM COMMENTS _acrroe ssc c=as■ cz ■cccna=sccco=se iT. _rxmwv== tf..r pm=..mZ Cxasr 75-0135 C 13921 SE 136TH PL FLDG SWAMP/SE 136TH PL/HIDEWAY HTS b56J2 81-0197 C 13832 SE 131ST ST/REN T DRNG BLKED 656J2 82-0341 C 14005 SE 133RD ST FLOG 656J2 82.0386 C 12808 138TH AVE SE DRNG & FLDG 656J2 82-0491 C 14009 SE 128TH ST FLDG MAPLEWOOD HTS 82 0525 C 16935 116TH AVE SE DVR as SE 132ND/144TH AVE SE 656J2 83-0353 C 13224 144TH AVE SE FLDG 656J2 ,4-¢ C 140XX SE 132ND ST DVR FLOG 8t5j-:jl= C 14100 SE 132ND ST DRNG SEE 84-1005/TO ROADS 656J2 86-01D9 C 14011 SE 132ND ST DRNG SURFACE WATER b56J2 86-01D9 C SEE YARN STUDY 656J2 656J2 86-0256 F 656J2 86-0256 C 256 S1 COMMITTED DATEt1ST GTR 1989. 656J2 86-0 86-0256 C 138TH AVE SE DRNG SYSTEM SILTED 656J2 PROS CRTD. 656J2 86.03Ai E 86-0739 C 13323 146TH AVE SE FLDG WATER FROM SCHOOL 656J2 87.0255 C 14639 SE 132ND ST FLDG STANDING WATER 8 MUD 656J2 87.0328 C 13323 146TH AVE SE DRNG CO DIVERTED DRNG ONTO PROPERTY 656J2 87-0405 C 13025 138TH AVE SE FLOG SEE 87-0463 OVER STREET 656J2 87-0445 C 13837 SE 128TH ST FLDG FILLING OF LOT 656J2 87.04 5 ER 13837 SE 126TH ST FLDG SEE 86.03A4 PENTON, 87-0707 656J2 87-0463 X 13025 138TH AVE SE FLDG ON 138TH AVE SE 656J2 88.0280 C 14106 SE 135TH ST DRNG STRORM DRAIN FAILURE 656J2 89-0036 C 14003 SE 132ND ST DEBRIS DEBRI ON RD TO DET POND 656J2 89-0113 C 13852 SE 128TH AVE DRNG DRAINAGE OF NEIGHBORS 656J2 FILL/ROAD CONST 89-0200 C 13120 138TH AVE SE SETTLING SINK HOLE IN YARD 656J2 89.0461 S2 14011 SE 132ND ST FLDG/DVR SEE!86-0256 YAHN PH I 656J2 89-0472 X 14105 SE 133RD ST 1NGUIRY STATUS OF STUDY(YAHN STUDY) 656J2 89-D636 X 14103 SE 132ND ST DRNG YAHN STUDY COMPLAINTS 656J2 90-0209 C 14639 S£ 132NO ST FLDG DITCN OVERFLOW/STORM EVENT 656J2 90-388 C 14105 SE 133RD ST DRNG FLOODING IN NBRHD 656J2 90-0512 C 13600 138TH AVE SE DRNG CROSS PIPE ERODING RAVINE 656J2 90.0556 C 13323 146TH AVE SE DRNG DITCH ENDS/DIVERTED WATER 65632 90-0556 ER 13323 146TH AVE SE DRNG XPIPE AND POND/DITCH ENDS 656J2 90.0804 X 14105 SE 133RD ST FLDG COMPLETION OF STUDY 90-I511 X 14105 SE 133RD ST FLDG CAPACITY OF PLAT DRNG 656J2 91-0081 X 14105 S 133RD ST DRNG CCF#191-32/YAHN STUDY/FLOODED 656J2 YARD 991_0081 SR 14105 S 133RD ST DRNG PUGET COLONY HOMES 656J2 91-0098 X 14105 SE 133RD ST DRNG CCF#SWMp124/DEVELOPEMENT 656J2 gl:kQ98 SR 14105 SE 133RD ST DRNG CCFNSWM0124 PUGET COLONY HOMES 656J2 ,91-0246 C 14013 SE 133RD ST DRNG PLUGGED 656J2 91-0246 SR 14013 SE 133RD ST DRNG PLUGGED PUGET COLONY HOMES 656J2 „91-0315 C 14011 SE 132ND FLDG DIVERSION/CULVERT OVERFLOW 656J2 91.0636 X 14105 SE 133RD ST FLDG CCF#491-32/PLAT DRAINAGE 656J2 91-0636 NDA 14105 SE 133RD ST FLOG CCF#491.32 NOT NDA PUGET 656J2 COLONY HOMES -0 X 14105 SE 133RD ST DRNG CCF0591-2 SAME OLD PROB 656J2 91-0650 NDA 14105 SE 133RD ST DRNG CCF#591-2 NOT NDA PUGET 656J2 COLONY HOMES EXHIBIT F SENSITIVE AREAS FOLIO T lb' d r - Mercer Slough Wee -444 Lake ca J z ' East Sammamish -D.141 J 1- v, ks .- r{{ �; —`. me�crook y:m , 28b ( a rY i v _ ft }`'�� ' Lb � - J_ - fr � tt 123b i{21b" s i ILI IUD , m . k lac hG ;, 'r l: i •' ,3 4�LLLL211 30 .LPL �Z•,yr-�?`� , t Cr t those with an `_]^���ri�n Fm yyad�, Duwam sh q e included in the Wetlands J Iru,entory. The �.,2Ij 7.'r. --- -� 's designated "a" have Open Wd w z site by a variety of ,,,t.._-:J1 �siynated 'b"are map- Basin Boundaries i',, 9 14 A t n and Wildlife Service 111\YI rcnl,ry,but their Iota- 'F;,,r 5";',:_i ,clo verified. �� Sub-basin Boundaries ,_-C41 1 in the numbering se- 12 - • vldual drainage basins. u_ � y 1 ir 761 Ij -?-im -��(- � i. E E 7 r,t 1 .��t •,\ t p �' i L' -- rJ`ITT �J ! t_.-� \ `�`r\'� kill t / 4krt �� C�i 1 i 7"T• z o J Tr - I^ • �r • P't i- . r .I - ��� Class 1 C3UWaiTltSh .[�. 1-.. ;dplai. extend be_ Streams and 100 _ in on maps Flood In- �—�-. + . Class 2(with salmonids) s do not always show thej headwaters of streams. Year 1 100d 1`dinS Class 2(perennial;salmonid r,a 1 P use undetermined) . . . . . Class 3 N �,,, +r Fioodplalns _ _ _ Unclassified .12 4 w����• � � pia. A lift EL « FA MIL "I Will 'ASH., i�': ♦ 4 Mill ll cif,.�' \•aow.� r s al 01111 all aw flip ■ tl,� MINO E $' 141114 FIR ,mks all INA �► 1 ��a; � HAWMIMAN �'� ���� � �� ljf�� erg r--• .aK,:. a.,_ r, if ■v � � a 0 IS pa r t ? •am �. MIN MOVE ..� ..rO..� - i =11 f !1 f .� _ � Mn �►' ow Out "fP6� Mw ` ' Illn all � �.- .. ■ uiw i too ra b r > f Cd�� __ — � n S Y )/,� �1 z.. ;! 1 •fJ � _....� l.h•�t1 � �' {: ) '�..R, �/ r' ._ ` i - `' ,^'"'•".•.- Y f i l ;(.r , �� i Yr ra., t a N n d > �)}' �' { sii Y fy :.�• Ir w� y i .. ye, }{f 44, CA CA y 'a � d - ( a' , +s •� t �p;�'+`j r. � � V'� 13' i !�,° .,.,i •L�_�,�� 1. _yt„t7. � "._(�.,.. ��N.o d� •F ,�/'�) ; { (s, ,f" `< I i- �il` i ,•� �:,' �i + �. _ r-G 1 --t � .r. ` •,r s�• ✓$N d _r. 1 � � j' f�—('"')x i [ rt �_y�t�} � '7 '. ) sT:,. `� -tea' •�..' .�, � � �`L x' y �^ �`F /}>3, _ 31 I� ( ; • ave ..%Mom, t \'•f,, � �rf• -c r"� �-r � �wtJl`` �.� - ti �• -1 % I � f.. '•wL.",^•*y.Yriy"�'""• ! (. ( �� � _ ITT- �:•• ,/ram +,� �-�� � � '� -� — I 1 L 1 ��-,,. �. I t.`7, .yele ��ty�✓);/ -i ,�S/ +, �1(+ i t�� ', p^•� r)� { .-�_:. "7�tY7�'�\,•���)_ C 1 '.f�Y•t t, ! - � � j rJ, >.:,raySJ. � -r .!'-. f t C.1\�_1J-1�/ t ! / :..) ..r e �•. 1C a1L� 111 1 4 /'�i f` ) `���, �i/ � j � J .� T/ _ _ 1 �/,�1. ll�t... � ��� __, ''"� � •— ��_" 'y � Q .'�G \ \ � .� ' 'y"- ( 1 �11.- — r: -.tfj * '1 •/`l�1/2/ /Y-1=`c'C'� -._,.� �c,! Air W � y ' r •. ;' / + 1 Yy ,C{, ��/y'J�` v 1t�� 'AR( 44 i� It . MUM Hill S e Willi ,w illy ' Iilf ' ..teaf��to �ysr� Will NJ INN III ' WWI ml IN mot ,.� Mal Him s { , FROM:KING CO. DEPT.NR WLRD TO: 2062518782 S206 JUL 9, 1997 10:46AN P.03 91-0682 CL 14105 SE 133RD ST FLOG CCFft 591=2 DUE JULY 656J2 91-0712 X 14103 SE 132ND ST DRHG CCF# SUN 0520 MANY COMP 656J2 1-0712 NDA 14103 SE 132ND ST DRNG CCF# SUM 0520 NOT NDA PUGET 656J2 COLONY HOME DRAINAGE NEIGHBORHOOD FLOODING 656J2 91-0715 C 14105 SE 133RD ST 656J2 �1 0715 SR 14105 BE 133RD ST DRAINAGE PUGET COLONY HOMES 91-0723 X 14105 SE 133PD ST DRAINAGE CCFtI 591-37 656J2 91-0723 SR 14105 SE 133RD ST DRAINAGE CCF# 591-37 PUGET COLONY HOMES 656J2 9l.073 C 14024 SE 133RD ST DRAINAGE /LAMB (CLAIM) 91.0732 SR 14024 SE 133RD ST DRAINAGE /LAMB (CLAIM) NOT NDAP 656J2 91• 9 SR 14103 SE 132ND ST DRNG/FLD CCF0 SWM-0610 NOT NDAP 656J2 21.0777 X 14103 SE 132WD ST FLOODING CCF# 591-39 656J2 g1_Q T7 NDA 14103 S£ 132ND ST FLOODING CCF# 591-39 NOT NDA PUGET 656J2 COLONY 91.0812 C 14639 SE 132ND ST DRAINAGE 656J2 91-0668 X 14010 SE 134TH ST DRAINAGE CCF# SWM02n/PUGET COLONY 656J2 91� SR 14010 SE 134TH ST DRAINAGE CCF# SW0279 NOT NDAP 91-0888 X 13800 SE 128TH ST FLOWING CCF# swm-085WETAND FLOODING CCF#S1M 852?NOTLNDA-PUGETEMS 656J2 91-0888 SR 13800 SE 128TH ST COLONY HOMES 91-0946 X 14105 SE 133RD ST DRAINAGE CCF#: 91-0822/GRANTING 656J2 EASEMENTS 91-1214 X 14105 SE 133RD DRAINAGE CCF# SUN 1217/PROJECT SCHEDU(_E 656J2 93-0179 C 137XX 144TH AVE SE DIVERSON POSS CLEARING VIOLATION 656H2 93.0239 X 14105 SE 133RD ST INQUIRY INFO ONLY 93.1064 C 14400 SE 136TH ST FLOG GROUND WATER UNDER ROADWAY 656J2 95-0763 C 14010 SE 134TH ST VACATION DRAINAGE IMPACT FROM VACATION 656H2 --� REQUEST -1283 C 140TH SE 132RD -135TH SE CIP REQUEST TO DO ASSESSMENT OF 656H2 CONVEYANCE 97- b5bJ2 5 C 14105 SE 133RD ST FLOG PUGET COLONY HOMES 656J2 �Q055 R 14105 SE 133RD ST FLOG PUGET COLONY HOMES 97-0055 NDA 14105 SE 133RD ST FLOG PUGET COLONY HOMES 656J2 EXHIBIT I KING COUNTY SOIL SURVEY SOIL SURVEY CountyKing Washington UNITED STATES DEPARTMENT OF AGRICULTURE Soil Conservation Service in cooperation with WASHINGTON AGRICULTURAL EXPERIMENT STATION Issued November 1973 • •• � •ks a ,f y _,"�3•• �_ !� � ,r 1 ' /' � N r// {,.1 e��'. pap ...� g�'• q ,r -il •`~Q ^,r0I it" M ".-r�^. r ,• r, •�• ,i` ; t�i 1 ,-.� -L ..«:1' 4". 1,' �i.: r :t ''t' /�. :Yg�, �s'6 / _ 'r,4r y �t� .g, ' •P.: '�sl ' r r • Y;.. �, ,•I• ;lea.; 0 F "z M� J� r >�' of /'\ �� �: .i.X d;�•c. •J e } � t 1 c r�. 0. `� � h • � •'k t� n A''Ti, .r (.r •1 �-ti(�- 'f �"N"..�a • :.y• g�•, r �,� � - O ^s ��, 1. .t3:• y. ��„ ,i r {�' Z T Ir �.l'1 r �•ti:�. 00. �/ , ,� +t `I+' .`.C ' �- ;.;•r•%ti•,. r�" ^. tq.'� �r ,�j- ;� ',. ��:..''„r„�'�•'x'�.' a. g' r �,/ r P 1• •2• 11 '• A �� � ,.� •`r `` i r }}.' ___ / .� d+'p54.^'T�"�, � /y � •1''� .1 • m •`.�"� II ��r . 'R. '� �a 3���^� lMt�' �.. .�-r�:. '� '�1`. 1 1 ''?`I'�, � a /,�" q > t'i"' a ;.'••. 'i I)- r ,. � �' ���'pSy.'f` " 'G a r,'47�' �e s 1 / r �.. ( ' f' �+ 0 t. q i mf rd'.c' •.r �. .? •+� 3} � i � - it � ,� s •��� n+ �! r ��i �i � m / x �'�'�• f..alt a Q� � � ' '..: •a, .k . I . .t/ •SS' • Q �—//�u r t , � Gt ,��< ¢/ � � O` � Z ;f,�,.'�,. kj N� �3t � s ••+"` •^ / ' �,.. +b '�.'►fi 11 `,a +:,1c � til;�l9 ;� O )1t m T. • r• y t v i ra �.. Ir,. �• M -• izSP- �;;• ' > •/ Q • :,-�''�• :j 4� i -I� 'q // Q s ,a' , ^11 ' f tx.: �K i . r - a� ,_-,I 1" / � _ -I, � i N • iti. 1 a •.y m .r ,�,��ii .• � �V ,}rs`� w� Y'1tS• P P,: ,.t. • } trl • � �� t/ ♦\ -� rr r ' // 1a":.e .'Ir/ Y •+s •.r �.A�V. ��.•,.�, 1. (;�... :4 •�. � I � �"�4: ' s,� �+"l�yalrr•l�I•. ._�� 4.4«,• ca •G,r�' 1 i�. •• �� i,.� •' �S�d!• `\•»� ,p�$•:v�: t$i- � "/ �i:_� r ti ry`���, � - _r •e '!/y'SC ••al :.Us 1 �• t .'t' YL. 3q) s}a`' p orj,,. r r. 4 4 / ,7�WYf*3•,J.'�3 7 n 4 y� •{aO�, �,� r '�::6 •� �'��.k' •`^.1 � ryS ,• �f. I? 4%ems '7f;�W� ;ar�I.' /`7 i`.' y • 1 + : �1 X t � L ; } it . 'q Y I �i' 3'� dyL. .t''�M• / t.� � �• 4 A � .1'. / pit't r� t�� \ r 1 a�, '� /1•'�'. Y. gal... I �� e. �.. ,._ t •' r.z � r,'.a' -:.p t .. .� '1,"'; JC�f� J�L•'�'M:• �� •„FFr• i, ��'Fc �.• :e ��• # .yp ��d �I i n• m G r t t• Ca :r• `r•.•�. 4°V''''1V'�''/s.`t; 'Oe i[ �,.h ✓:.c 13 « e o ��r ; ey t� S I 1 n _ •Y �, .`f '�+ s ;. 11 �. :'� it ai f. � .F. g;�.... I• �3 ? �.. � � x r• �. 1�,+ r • ��"►s y ,.;� '.; t.• ��� �'a H�„�QEt/' _ �,:c S P4' a y,. � - . . a`it'� `��/rye �I •�. •Y '" �C` �fsy = � r ; g:Q• r"a'=s},?�+.,, ,t' '�_ t;Y:t. �'',1.3 111 { p <�7;';,�o ,�t:.,,•. �' o%T• t, // t •a, a ��r•� � �f`i'1 / r.H 9 , _. Q-#" *�r`t'. � , . ' � ��'11. `r'_...:A .... � .. �,� ,•• - ../^ it 1•....✓f Y �4� - ��� �J. �.� .,', w•r ; u1.^, '•�`: - I 1 +' - -�'I `' ).ate.. J } ,L� I� � t t.• I U� Y ��.X 1 �,. t,�„•Fi -.: �/ � _ -_ •. a_ -� •__ � � ��� v: .a•ri -1 t" ��/'y / � •U ��yt lr Q. r ��<-'�• �� �/'_� C+. � `ti. ]..G r '!f • `t_•-1•••\♦�• -� J '! S t , //'li/•' / i� M S70 1 `� r I,..y. .; l�I r r;j� � �.W to o i..�._'-'(..Y�.' ;• +.a � o'� �s� � � t t1. �_ •.0 J4 �:�.♦•�••J•• t I Q •.i �� w� `; < �m,`� J i' , • 1..',•..� t^. i«I - r. � • i �•o,>• S.. •� d j. .t'!J t'' i, �'.4! � m Q._ r .w � �, +, y�f,, � ♦ •_`` «:9« .t + ' f S oR �r! 'i•• 't Jf�~ -'}'V'.. ;-7�, �,,�_ -_�O ' dy f�\'., a�t4i �'i�;�f y � j.'"+a�i m0p � Upq'o...�Ai' ' +�''i i 4A. '+:• 'Cf 17 i•� :�,•+ J ,;� S '�L':•yAG"' —'y "� � / t, .A4' �,.' •1`` J,�. `' Yq}•�'.. RR, s 4 a �i0 , ¢ 2� '¢ ; •m Q�I. •=.f• ..iia•Pf .ti�' 4' u 9, A, Y4++ ♦ 1��`01. ` •� .., yt • n, 7• -- s y-:•.. ¢ �l t••�•7ii �'�:. :•t � �•,•" fl+ +�� ,�'S/�1 A� ,ryS,=1'� .. ya� e-. 1 � �I K M1 d� 1 t •+.. t• j f ,\ .ti � � y j� �. 1 // ,�`t` J • +•L�' 1,• r� F :�* a f1l • m �_ .7 �1�` %':t; ., .a tv };.1 Ej•�x �� t'i •'-P U ppra .. ,_Q� .✓ .. .V •' i Vx. t 1�s E. �;, yl. �'�' d't - E.I yf4 04 r -. �� ••. a v ,� �� e yam•' .'�,Q., ���Ski��' 'r� i �E. � ':.., -p� t'�-r;r �'�¢:' i / ' -- �■ m ?ir a nS ;,r• t ;�f.;,�y N r y, � t* ��' 'l1'�' � � t .. ., ��-• ,I ' ': + •� GUIDE TO MAPPING UNITS For a full description of a mapping unit, read both the description of the mapping unit and that of the soil series to which the mapping unit belongs. See table 6, page 70, for descriptions of woodland groups. Other information is given in tables as follows: Acreage and extent, table 1, page 9. Town and country planning, table 4, page 57. Engineering uses of the soils, tables 2 and 3, Recreational uses, table 5, page 64. pages 36 through 55. Estimated yields, table 7, page 79. Woodland Described Capability unit group Map on symbol Mapping unit page Symbol Page Symbol AgB Alderwood gravelly sandy loam, 0 to 6 percent slopes---------- 10 IVe-2 76 3d2 AgC Alderwood gravelly sandy loam, 6 to 15 percent slopes--------- 8 IVe-2 76 3d1 AgD Alderwood gravelly sandy loam, 15 to 30 percent slopes-------- 10 VIe-2 78 3d1 AkF Alderwood and Kitsap soils, very steep------------------------ 10 VIIe-1 78 2dl AmB Arents, Alderwood material, 0 to 6 percent slopes 1/---------- 10 IVe-2 76 3d2 AmC Arents, Alderwood material, 6 to 15 percent slopes 1/--------- 10 IVe-2 76 3d2 An Arents, Everett material l/----------------------------------- 11 IVs-1 77 3f3 BeC Beausite gravelly sandy loam, 6 to 15 percent slopes---------- 11 IVe-2 76 3d2 BeD Beausite gravelly sandy loam, 15 to 30 percent slopes--------- 12 VIe-2 78 3dl BeF Beausite gravelly sandy loam, 40 to 75 percent slopes--------- 12 VIIe-1 78 3dl Bh Bellingham silt loam------------------------------------------ 12 IIIw-2 76 3w2 Br Briscot silt loam--------------------------------------------- 13 IIw-2 75 3w1 Bu Buckley silt loam--------------------------------------------- 13 IIIw-2 76 4wl Cb Coastal beaches----------------------------------------------- 14 VIIIw-1 78 --- Ea Earlmont silt loam------------------------------------- ------ 14 IIw-2 75 3w2 Ed Edgewick fine sandy loam-------------------------------------- 15 IIIw-1 75 2ol EvB Everett gravelly sandy loam, 0 to 5 percent slopes------------ 15 IVs-1 77 3f3 EvC Everett gravelly sandy loam, 5 to 15 percent slopes----------- 16 VIs-1 78 3f3 EvD Everett gravelly sandy loam, 15 to 30 percent slopes---------- 16 VIe-1 77 3f2 EwC 'Everett-Alderwood gravelly sandy loans, 6 to 15 percent slopes------------------------------------------------------ 16 VIs-1 78 3f3 InA Indianola loamy fine sand, 0 to 4 percent slopes-------------- 17 IVs-2 77 4s3 C Indianola loamy fine sand, 4 to 15 percent slopes------------- 16 IVs-2 77 4s3 iD Indianola loamy fine sand, 15 to 30 percent slopes------------ 17 VIe-1 76 4s2 _pB Kitsap silt loam, 2 to 8 percent slopes----------------------- 17 IIIe-1 75 2d2 KpC Kitsap silt loam, 8 to 15 percent slopes---------------------- 18 IVe-1 76 2d2 KpD Kitsap silt loam, 15 to 30 percent slopes--------------------- 18 VIe-2 78 2dl KsC Klaus gravelly loamy sand, 6 to 15 percent slopes------------- 18 VIs-1 78 3fl Ma Mixed alluvial land------------------------------------------- 18 VIw-2 78 2ol NeC Neilton very gravelly loamy sand, 2 to 15 percent slopes------ 19 VIs-1 78 3f3 Ng Newberg silt loam--------------------------------------------- 19 IIw-1 74 2ol Nk Nooksack silt loam-------------------------------------------- 20 IIw-1 74 2ol No Norma sandy loam---------------------------------------------- 20 IIIw-3 76 3w2 Or Orcas peat---------------------------------------------------- 21 VIIIw-1 78 --- Os Oridia silt loam---------------------------------------------- 21 IIw-2 75 3wl OvC Ovall gravelly loam, 0 to 15 percent slopes------------------- 22 IVe-2 76 3dl OvD Ovall gravelly loam, 15 to 25 percent slopes------------------ 23 VIe-2 78 3dl OvF Ovall gravelly loam, 40 to 7S percent slopes------------------ 23 VIIe-1 78 3dl Pc Pilchuck loamy fine sand-------------------------------------- 23 VIw-1 78 2sl Pk Pilchuck fine sandy loam-------------------------------------- 23 IVw-1 76 2sl Pu Puget silty clay loam----------------------------------------- 24 IIIw-2 76 3w2 Py Puyallup fine sandy loam-------------------------------------- 24 IIw-1 74 2ol RaC Ragnar fine sandy loam, 6 to 15 percent slopes---------------- 25 IVe-3 77 4sl RaD Ragnar fine sandy loam, 15 to 25 percent slopes--------------- 26 VIe-2 78 4sl RdC Ragnar-Indianola association, sloping: 1/---------------------- 26 -------- -- Ragnar soil--------------------------------------------- -- IVe-3 77 4sl Indianola soil------------------------------------------- -- IVs-2 77 4s3 RdE Ragnar-Indianola association, moderately steep: 1/------------ 26 -------- -- Ragnar soil--------------------------------------------- -- VIe-2 78 4sl Indianola soil------------------------------------------- -- VIe-1 77 4s2 U. S. GOVERNMENT PRINTING OFFICE:1973 0-468-266 GUIDE TO MAPPING UNITS--Continued Woodland Described Capability unit group Map on ,mbol Mapping unit page Symbol Page Symbol Re Renton silt loam-------------------------------------------- 26 IIIw-1 75 3wl Rh Rivenaash--------------------------------------------------- 27 VIIIw-1 78 --- Sa Salal silt loam--------------------------------------------- 27 IIw-1 74 2ol Sh Sammamish silt loam----------------------------------------- 27 IIw-2 75 3wl Sk Seattle muck------------------------------------------------ 28 IIw-3 75 --- Sm Shalcar muck------------------------------------------------ 29 IIw-3 75 --- Sn Si silt loam------------------------------------------------ 29 IIw-1 74 2ol So Snohomish silt loam----------------------------------------- 30 IIw-2 .75 3w2 Sr Snohomish silt loam, thick surface variant------------------ 31 IIw-2 75 3w2 Su Sultan silt loam-------------------------------------------- 31 IIw-1 74 3w1 Tu Tukwila muck------------------------------------------------ 32 IIw-3 75 --- Ur Urban land------- -------- -- --- Wo Woodinville silt loam--------------------------------------- 33 IIw-2 75 3w2 1/ The composition of these traits is more variable than that of the others in the Area, but it has been controlled well enough to interpret for the expected use of the soils.