The URL can be used to link to this page

Home My WebLink About03096 - Technical Information Report � TECHNICAL INFORMATION REPORT a 0 m Mapleton Short Plat NEC - N.E. 6th Court and Blaine Court N.E. , Section 8, Township 23 North, Range 5 East, Willamette Meridian Renton, King County, Washington City of Renton File No. LUA-01 -158, SHPL-H Prepared for: Michael J. Prittie 8910 — 8th Avenue N.E. Seattle, WA 98115 September 30, 2002 Our Job No. 10128 ti p. GI�tr ��°�W � � �� f y i � 239 � Q- �`�, TER� `��li�v � SS�ONAI.ENG ,J J�� GHAVS �' EXPIRES: 6 /10 / u ' � "I,� 'Z CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES 18215 72ND AVENUE SOUTH, KEtvT WA 98032 • (425) 251-6222 • (425) 251-8782 Fax n ci � ��U' ? www.barghausen.com �G �i� <p� ��,P NG ENG�N 30� � TECHNICAL INFORMATION REPORT Mapieton Short Plat ?- .3� �E . NEC - N.E. 6th Court and Blaine Court N.E. Section 8, Township 23 North, Range 5 East, Willamette Meridian Renton, King County, Washington City of Renton File No. LUA-01 -158, SHPL-H Prepared for: Michael J. Prittie �,NOF,�o� 8910 — 8th Avenue N.E. RECFivs� Seattle, WA 98115 �1i � "�i�1 i � !l: ' -3 � %.vU ��STa„�,�";,��,� September 30, 2002 Our Job No. 10128 ti Y. GIt� ,�,R��°F W � �� y r f 239 � �Q- . �c�, 7'ER� `�a�i , SS�ONAL�G ��U?j ¢GK A(�s ,� EXPiRES: 6 /1 Q / �i m '►I� 2 CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES � ` - 1821b 72ND AVENUE SOUTH, KENT WA 98032 • (425) 251-6222 . (425) 251-8782 Fax n U i � ? www.barghausen.com G� I,� P0' T� EE NG ENGtN TABLE OF CONTENTS 1 A INTRODUCTION AND GENERAL INFORMATION Figure 1 —Technical Information Report(TIR)Worksheet Figure 2—Site Location Figure 3—Drainage Basin Figure 4—Soils 2.0 ANALYSIS OF SEVEN CORE REQUIREMENTS AND HEARING EXAMINER'S CONDITIONS 2.1 Analysis of Core Requirements 2.2 Summary of Hearing Examiner's Conditions 3.0 OFF-SITE ANALYSIS 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 4.1 Existing Site Hydrology 4.2 Developed Site Hydrology 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN 6.0 SPECIAL REPORTS AND STUDIES 6.l Level I Downstream Analysis Report Dated August 16,2001 6.2 Geotechnical Engineering Study by Earth Consultants Dated May 2, 2002 7.0 OTHER PERMITS 7.1 City of Renton Street Name and Address Approval 72 City of Renton Postmaster Approval 7.3 City of Renton Fire Hydrant Loca[ion Approval 8.0 ESC ANALYSIS AND DESIGN 9.0 BOND QUANTITIES AND FACILITY SLTMMARIES 10128.015.doc[HPG/tep] LU INTRODUCTION AND GENERAL INFORMATION The proposed Mapleton short plat is located in a portion of the northeast quarter of the southeast quarter of Section 8, Township 23 North, Range 5 East, Willamette Meridian, City of Renton, King County, Washington. More particvlarly, it is located in the northeast quadrant of N.E. 6th Court and Blaine Court N.E. and consists of approximately 1.16 acres. The site is proposed to be developed into seven single-famiiy lots. The existing topography of the site is fairly steep with slopes of up to 14 percent sloping from the eastern side towards the western portion. Most of the property is covered with grass, ��vith the exception of the existing house and associated outbuildings and driveway. This existing house is proposed to remain and will be located on future Lot 4. The access proposed for this project will be a roadway from the intersection of N.E. 6th Court and Blaine Court N.E. accessing into the property with a hammerhead turnaround for emergency fire access. Storm drainage runoff from this project is proposed to be collected and routed through a biofiltration swale designed in accordance with the 1990 King County Surface Water Design Manual. Detention is not required for this project because of the difference in the pre- and post-developed 100-year/24-hour storm events. The difference in these storm events from the existing state to the post-developed state is less than 0.5 cubic feet per second. 10128.O15.doc[HPG/tep] «: FIGURE 1 TECHNICAL INFORMATION REPORT (TIR) WORKSHEET King County Department of Development and Environmental Services TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PRWECT ENGINEER Part 2 PROJECT LOCA710N AND DESCRIPTION, -�,:' ` Project Owner Michael J. Prittie Project Name Address 8910- 8th Avenue N.E. Seattle 9813 5 Ma leton Short Plat Phone (206) 544-0212 Location Project Engineer Hal P. Grubb, P.E. Township 23 North Company Bar hausen Consultin En ineers, Inc. Range 5 East Address/Phone 18215—72nd Avenue South Section 8 Kent, WA 98032/(425)251-6222 I Part 3 TYPE OF PERMIT APPUCATION Part 4 OTHER REVIEWS AND PERMITS- ❑ Subdivision HPA ❑ DFW HPA ❑ Shoreline Management � Short Subdivision ❑ COE 404 ❑ Rockery � Grading ❑ DOE Dam Safety ❑ Structural Vaults ❑ Commercia� ❑ FEMA Floodplain ❑ Other ❑ Other ❑ COE Wetlands 4:- �s. Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community Drainage Basin ' Lake Washin ton Part 6 SITE CHARACTERISTICS �`'�� : �� ' _�' �` �y =�-��,,. �,�� t � �E _ ,et �-��.�s�:. �� s ❑ River ❑ Floodplain p Stream p wetlands ❑ Critical Stream Reach ❑ Seeps/Springs ❑ Depressions/Swales ❑ High Groundwater Table ❑ Lake ❑ Groundwater Recharge ❑ Steep Slopes ❑ Other -1- 10128.016.doc .. - � . .'� � �, �� :.r �-`r�� ..- s fy :` _ _ ' Part 7: SOILS _ „ �, ;�� ,��=� ,.�;� ,-; � r -, f � ,k.,� Soil Type Slopes Erosion Potential Erosive Velocities A C 2- IS% ❑ Additional Sheets Attached Part 8 DEVELOPMENT LIMITATIONS REFERENCE LIMITATION/SITE CONSTRAINT ❑ ❑ ❑ 0 ❑ Additional Sheets Attached Part 9 ESC REQUIREMENTS ' = 3 ,= MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION � Sedimentation Facilities � Stabilize Exposed Suriace � Stabilized Construction Entrance ❑ Remove and Restore Temporary ESC Facilities � Perimeter Runoff Control � Clean and Remove All Silt and Debris � ❑ Clearing and Grading Restrictions � Ensure Operation ot Permanent Facilities 'I � Cover Practices ❑ Flag Limits of SAO and Open Space Preservation Areas , ❑ Construction Sequence ❑ Other � ❑ Other . .- �, �.�s =� : �e Part 10 SURFACE WATER SYSTEM _ �� . _ :�; , ; ,� ; � , �`_ , � Grass Lined Channel ❑ Tank ❑ Infiltration Method of Analysis � Pipe System ❑ Vault ❑ Depression SBUH ❑ Open Channel ❑ Energy Dissipater ❑ Flow Dispersal CompensatioNMitigation ❑ Dry Pond ❑ Wetland ❑ Waiver of Eliminated Site ❑ Wet Pond ❑ Stream ❑ Regional Detention Storage Brief Description of System Operation Catch basins and conve ance i es for runoff collection and routin throu h a bioswale for treatment rior to site dischar e. Facility Related Site Limitations Reference Facility Limitation -2- 10128.016.doc : �. : � - �-.. -. .�::-- a � � "'h a. --'�`'•5�" },«'. Part 11 STRUCTURAL ANALYSIS _ �Y � ; P,art 12� EASEMENTSlTRACTS ;F��_ a ' - ?� �• - � � .� ❑ Cast in Place Vauit ❑ Drainage Easement ❑ Retaining Wall ❑ Access Easement ❑ Rockery>4'High ❑ Native Growth Protection Easement ❑ Structural on Steep Slope ❑ Tract ❑ Other ❑ Other Pa�t 13 SIGNATURE OF PROFESSIONAL ENGINEER = � �: :- I,or a civit engineer under my supervision,have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attachments. o the t y)cnowledge the information provided here is accurate. / ��Q -�`� - Si ned/Dated k 1_ F __ `�'�..�' -3- ioizs.oi6.do� � � N �""r w � � � � � � O � a ww � � � � � �� .� �Y4;40 `�`,rr n 80TH P�SE r � �'� wTM"v�t � (7 5 _ _ � 4 iQ +P 37 i ! m � (11 ar 78T �^ �AV S � "s u � �� `�" -r TN vt E `�� I `, �' ��81ST k ,*y �S m� � �� 79 H�.'" AV �' S N S 79 yl S1M(.' a,�c�� Y� � `' � 5 �/�n m � l4 0�� m � C BOTH �� N Vf-1� �^ S.�b 1� �a o,r J, � �'�� ` "m � o E. Z � � � AV .�, 4�.;:., S 9 TH� AY 5 s�� 5^ y. ' ��6` � �� S� �1' }, ' A� cn� p M¢� � S�a N'.,N I.-- �, , 1 .�..;'�., r,��' � �' �� '-�l� '�n � TH AV SE ��"1 .E � � , �i N�„ '� `' !1. �r $ �B -� }� 2 � TH PL g^ rn 'e��`�� AV �.,� B1ST,. e�s � s -P `' � ' s as��e 3 �+ �O 0 f�'1 " PL"' x~ p ✓' � . f Hy`' 8� �,S 85T ,y.�. � •, � N � C}o ..+ .,. -- B2 �,�' S > � � � BF'y0r � J� � � �. �m�� . � ,v ro �, •,t,j a(� �•-, _, hPj K .+ , a y r' o '� � � ` -"i 4TH �� q �� i� '$ °( � �:� `�'�,S 14 V s S G�� tj � , B',� � C `� � 1 90 � ,.,,1 300,., 11000 � m " e rH� " � �, -a �n W �l � ' `S � m �' S eo C�� •�� "� ;', '� 8 96TN C7 S m y � v+�<n �� . . .. `- - ��'9 s�:c .'.�, m s .�. 87TH AV� � � ~ � � .A��O �,s ia ' � u uxo.� � S y ��,F, b 1SI6 � �� AV �V ' -�i:. -ro+C RBTI�V`�S N � � S y {/� AV H16 U1 TAVLO�T `a .'-1 1�r S .. �1 �\ I�i1 9151� Z O � �V IN�N. �f S . . .� � V '�?'I: . .� � ' ,.�j� 92N AV 700� ,� N ,� �,+N!.� :��A ,.. � k . �'�'�:. . ,I�A-.= 9/T� s`�ti .' , .:,�� _`-. ,2�� < ada -:+. � ^ . 2f3AIa�---� ..�,r � t� `J "<'ar�,y '' mN � $a ,!��'(�r X.1. �l p ' "� � Y z � a0' �" 3 0 � � '� -�� -� T� � $ � ' ----- � � <-� m 'J � , a�d ,�...., g�i \ � �'� .�\ �,�� A � �'�, 8 z �'� ��, D � �`._ � i� BUR g y N , -��. � b �F \�` /�� ~ �i�.i = � �`� Z 2 \ � � ` � � ��' ��.i = '�� i � � � � � � ,� � weeu'v a._ \\ \��,./��, PARK '` � .� ;..�. t I�= = AV N � �\ � � � I , NS�M=�� r4 `� AR� -�ni � AV� � � � N z `�'�,/.i F RDEN q 9,y � �� 01'��1 �PARK iC N �, ■ 33 0 3 0 g R, " N3�� q y '' ,� . �� a�� _ �" �.� � = �� ;� � N �d �'�- o FRWY �NM oa+ � MEADOW `-� W AV `a�N.-1 ;' ' a Ns �° -`�i � HIGH AU NE `��i q . ' JONES AV NE �' N"�y` "'p"J.��,sta, `y u 3E�NE : E RIP�fl' N ; �>m i oo � z000 �za o �� 1d .��'�N .�'�'� . 53 C �„ � � s= _ '�' 2 � KENNE K A NE 8 r=+ S � �`� �� + ~ �A y "�inttotH Av w CJ1 K ,a�'� ' � ��S LINCOLN��'�AV N LINCOLN � ~�''z �a�rtar� MO REY A }� NF � ro r� v�NTEREY �S2 I ��dA, �,�, 8400 NE _-_' ,'i .4Sh, � :�'xE SU�/�.�,� �+ 1400 HrE¢v � � V NE'q � � .1.��,�.,�m MONTEREY CT NE . 1a � �--"--lIin� -- R 5 y .�eeancEH�v�N ' ABERDEEN cr NE AV � NE � � � � i� r ^�� .j� �J�1� i s€ `b ~�� '9' � S2OO 2000 �, ^� � :: y' �g�w "d ay7,lt AV lRZTL _.--___.'N � � 11 Z "� z m m �NF � $�- BLAINE AV � NE ABERDEEN^�j UINE o v�� . 1 �3N��1a � �,V y�HLESi y� �" 113TH AV �T SE �{ `A M "� � � `^�yi = o � ^'UFuS AMAS��AV NE�PL NE � � � � ,��n '� �,�I 7 � �"' . _! D P'1 � o �S u AV A CWIS AV Vf� NE � ':'r�1�'. �� 7: Z � �I � M � w � -�i w � � � Z � � � A ` -t 1 � � � �� -� ��1�� 11ti,�`� , � � . � , r . � , , ;� 1111�1��;��', �t, ` � , �1 1 t� � 1� �'� 1 � rJ �1 1 �� ti , �� , �� 1f"'� � -� 4��,��11�, �� " 'I !�`�' , \ � � �111��.1\i�� t 1\�� . � t� - �\ �+-: w 4 I�>>t1��,�'�:` � �� T1 \ � . � � � "'`�' F; \ \ `\t \ 1 1 �''� �•��•� , -.� t , �1 '��\ n � \ .�,_ �� •, � • �� .��>> \ � 1 � �� .\ _ � �� \• `1\� `,`\�11� � � \� �:,, 1�. \`tt , � ,�l" � 1�,�; ., , � 1��' 1 �'��. ` `\ �1� (� � '��. : \ , �� 1��``t� T ..• � \�'�;:.�, �t � � ��11�1 1 �� 1 '. . `� '�,��t'�� t ��, � ` � `� �� \ ,� \� � � ` \'.��\\� l � � ,��,\, � ' � �`� �``�,�` , � t �'� `� �` `,� \�� \��\ � �� y ��\\ �. `�•..\\ .��`.\ 1\ �,` I `: 1 ��\�\ � \��•��.\'.`\\�\ �, � � ,� �� \��;;��;�� . , , ,,�� ,�; ,,, , - ` �� ..�.�:�.�.:,\ � � '� .,` �'i �� ,��-.'`�1:��`��'11�t`1 r .1� � �1 �\ �_..= •C.�,.��.�.�� ```� , `.,� ��`` \`•\\\\�'��. --� _ �1 �,,,,:, .. . �� \ . � � �,,,� �� ,� , . \..... ��=�\,��'�� \- " � `` , �,�`��. � , �_�-�, - � � �� ;-�_ ' � •, ` � ��'.`\�`- _;, ,it,�� '��`� _. �,'�� t�.� .:�' i�ti � tt�, �. � � ''�+" ` � �`�`; , � , �\\- ` \ ^ �'�` ��-�__`` � �.� ��., ,\, � l � -x: \� \ ` \��\ .,. � 1. v�. � � � l. ��.�r�`'�,.� � � ` '� � ,,� �`� � `� t� ti t__-=;��'� � `` � �` � �`11' �1it� �` \ � � '. . `�. ��l 1 1 1 1 _ _--_'.� .�.`� ,��:- ��,� \� ��1�� \ � � �' . •.�� '• �� , � \,�� 1 1 - `�.` �\ �h �' � , I� � �1 ;,� � \ � � � � � � � � � \\\'�`,�� ==�1'�� } � , 1 \ ' � '' `� \ � \� � ��,�:.� � � �� \ ` ` �. �/ '.. ` \ � � � � �. � ,\�.,, -^ � \ � ` �. ti � 1 \ '� � \ ` '�` �, � -,,,\ \ \ �� ``� �\\� ` \l� - � � \ � � �. \ � , �� \ � � ` � � ,� ,� � � � =',_ ` � , �� \ - ` �`� � / � 1 '� ', � j �. 1 � \ \ 1 � 1 �;.. � �� , ��-.'� �` ' \\ � V``~--� �\-. J \ � \ \ 1 �� ,�� .. � \ , � �, ;� � �l ��•�� .�. �� `' � �� t ` �� `-� .,. � � � �y � ��\ � . � �;�.�� ` �` , `��,�` �\ ti\\\'• \` � � � \ �=: \.",� �- � \ ` \` \ , �\\�) �� ,�\� �t �� `� �11�1�1t�, � \�11��\�` , � > >��1��\�� . . =�: � ��1�� . ` 1,,`` 1,, ` � ` , �� 1��1\�� ,�1 - t \ 1 1 `` , 11 11 ,v., �,' 1�`� ; 1 y .. ._.:'" � ��`t��l 1; .� t � t� t} , ` ` ,� ,� � {jjlf t�1� � � ` �. � \ �� 4� , � , t!' �� \ �\ .` �i� 1 1 � ---��_ , �., �� 1 1 � �� ! �� `4 . � � � ` ` �j�� 1 � /r i J \ � � ` �` 1 ' ` � 1 � ��` � � � •.r � '��_ , �. '•-- •� ".' ` . . � ' `'__ - _ � rv- r, /, . � �� d' w � T��., ~ V O F�1 � � , �I`� ',�ev. •Am � .�a1 ii -'-.i �� .. S �� , u"'% `... ��., .�'SG'.+� � , �� i�� i �:� --�---- N�= .r : .0 n:'�� f�7 , ^`i a . '�F' -:.W L- ' � i i. X �� y y� � � � .�a�^ ��; � ... i� , .:��,��' .. �,� ,f„u�t'� � �l�:� "''��:� �o�'�k� � Y � ��.� ,(i: :+ - f � ��.� . , v:� , k .4� � � w � � �� S ii � , m . �,�+I�":� �, a ,' I - i k�.� �l. �8ot -�'% � ,�"� '��' r n' `� '��: � �7 a` .5,. ' I m , ti, , . .a" �"`W� � r � ��'!j. 1: �m'' , ' '��R'Y�' .:.,y ..Y.� � I'' ��' .� �` �.r� oo � ' . F�. Y FM j . k .r, • J I '.A+N:'h � Z w J,a M f ' Q7 / . :. . .., ,� � " � .i • `�'�. r __� ,�m, �� n E� , . ., . �,, �;:' I �� I * �' �'d. �'� � t� a 's ' "' •� �� '� i�.� Q . �•.�.. < , a��.:� �a �. 4 • ' ,`t 4�Y 'f 'M N t' . ✓. y• b -.�^^ . . .�� II � I � ' �� .; , • .•.... �'i . �wk Q��t GI�'C = .A � ., �:�� +kL • 'k O$' .�'_ � �2'% �\ I . I� ol �:�o.. A. • . . . � . . h� � J�� .Y. � / � 7 1�; ,. i� � � • • Sii• m ��i da,�KCFf�y��"r' . �rf:a� y 4 ,.g� ,2p ec`{'. ~b � e;� � Q r'.�� „� A�' �. �" . I // . . �u • � • � � _ : S J tn7�( i �:.. . � t ��.3��lr i ��, ��'��f .� � :Q �► � . . +N''�` n c� ° �1 .� '+ ;..k � J II �� i .. � r t � ��, ��` � : � ln s> Ir r� x� �i i; r.LL � � i; i N � . -�- �� . � .. . ie •�� . 1 a �1 . .� .� :.��t',� �:` �.. ..T � j , I�, � ., _ . 'N II��yA�.� . �• e'.F � (. � ` a. II I '. . f� �"V \ 4..,, . II "� J , L 1 U .�y �r ...-, . �� / C� : i�� . T . .: I \� / q �� 4 a � m,_ ` �,. � ��n /��4 J '. � 1 .r �.4 4 � M :,f v�.. ,.a+��+ �„ o !�+� � � ,�a". �ll •"" 'r��, , � v�° 4 �y . I � �` ,.,� � � '�✓ .t� � � ��M 4 -0(I� u�r�. II � ��,� . . • x ' ti �,.�h� �� i� �f � '� � r� �� ,X fQ i �w,� ° k ��.', L �,, i I •t:� •� � W., i.:�p '' ^ .� , `,i / � f „� ,C �� ., > r.'� ..� � . � a�� ,�^`t �: � � 't � � � � , � � _ �� .� , �� ,. • � �, o � , • t� ,, . , . ��i ti � �r� � �. , � �� , I� ym��, ��+ �� l� �:� /� 'i �S' ... :�� .� �.1.-9' :�� W..s I �� '`r��m ��,� ��p� . ,� �e jr�' ./ � ,U '_� s1�°�y 1 � ;�, � t �.. W � �,.v'' 4�... • M ,.. p .� _ = t \ Q f .• � ,Q ...N , , , � - .,�fi. �,"N•` a s .. �. . Cr J . � , � � �� • .�• • ' � • �4.� . � \ k � m •. � .y � . . � �sR,��ue �� ,r .;.� ... ,.:_,�A i v"��,�,�, �'Nd i e ^t, 'S��o �V I* r 1— ,�+Ji�. - _ F�G �i�, ..?�� _ `+sl �tir.�'• � • �a�" �`,��. � �'Yadcj�'?�,��*5:ll�{ � f... i��' ' /`��\ ,� � D.h d� . ,,. +,,`.r�rp .•.,rl 5� .., � x.-1-. r� .ti '.�i s�'' �,t�q i Q.� �' ; 'Q U",m ea � Q - '- -'- -- _ _AM � � xn� „G ° ii x ..I �'a � o - �., . ' u- � "'� ��'''"' �; �!! :;' ,�r. • � a A� �:� � ,�:,, t � . +�j� :�. a . ^ __ ';II � .. '�. � „� w%S ��.'�. 1�1 "^' , .�,. _u s Y� - - I ��.{1� 3 P' � � � �;:.f'. 4�� , — e , \^ ��\ � ,,. �. a—.i� f"LU; i� � �• „�i r �� i�� 1 ' � • • ~� ' s� ' r • � �� hl -, // �N r � A � j>,i o� ��' %s �� ,1� /�'�� 1 �� '�`' �„ ,ii'��/E% �� ' �. �.,.i o i // �i / r� % ' ' i I �� _: ,. , :, � t•�,i. a`, �.:'ii C o� 't �:�,i'� C I :,,� o �,. /� i �...c_'� I � �_ � �l y ;u Q G o '�� r�+v �'F� /o I� � f .� E' � �� u �n ii �,.� �� t , r �i , �i � �'�' Q� �,�i. 'Q1 , ■ °e�£2�` ,t,ik�� =_��i/ ',�;,', ^Y ,� i f ��' � �'1 ' m � 1 � _ a l • i � � � � 2 � � ii ?� - � �r i i �� N . . � ^^ �i j � -_ � a ■ ii� �� i � � ��r � � '�� .� �m � �i w . I ( a -, ,.s _ •, , , ., , :�c �= a , x Qf 1.� � c, N ": ,. _-_, -,,- ,_ -� -; . � � �f/ � � �,, ,r ; �;,a: , �° . � � � < r� � '� � � '�..� .i r �. S�� .�� <'�� , q N \o �'vi d =-. �. � 131� '�r_ ��: .♦��i ♦ L� ".�r � ��^ �,� �r.'.`'i ' i �� )\. \�>/�' � �,�,.., ti. :.�i:., 2 ti r •� . � � i+ � �.C. � I- I� � i v 'i�R �l,c. r ` r,. �. . .z i r ..F�\.� yq , � �� T e a ;T � i� �� e G, . � `� �- �' .� .�.� _��'I� , . � ,�� }a � � �is.. �' c�'' Q • ! ��j . � .��_ � , `W ,�ii4� . (�.''.`'-i Z `.. �• P ' �.- F r^teo J'� . �� I' O �,` U i ��' � • �,:: ��Ei I , h�.t: f�� .I?�+ ' c � . w' � mfna- I . �.�� ri. ,I � . � , ; � � . � .,., r i ..... . —— .r �- —. ` - y j ......... • ' ' —,/—� - .� � r t w�" " m .. __ . .. . -c .� c,1 ..•,i; .'� ,� ��p'�t-F �`> � ��i'� I � � �Ati %�� I��m,�� ' h�x \ ��' '.}-.r, m • ,,�,, v N .� . � . .. '�` � `� ':'.1 . �OD .� . i. I E.�7 r:(= h � p � U �.•�ti '�p+��',,',�,�� .'i�. Q1i.4';��: �� I�i� �� ,,�!/ 1 ��U r�o <\\S( �O I`' . 'I:'r-�.� . "Q v .,Q�. ,G W A 1-.j � ! t• � �V( �7n,'� i7 �� /� 1 4�'' �/ 't I �V'F DD �G, C • , . 'Q 1�7 �.�" '• {�1 f�.v',!, . �� .5 ..'h r �� }c^K L f� �4� a0 r . y I a. 1 ,.�^{�f ,"It' - y ' � r'�:. ',�� I:�a�,: ..: �� _1 �• ��. !� �; J " . s° � ' .r.rr,� ��. � An � �, t �M �� p�% ¢ I 4 �� No Y ' : . ` ,. : � :,�A . ' -- . � �' ,�," � � � , A I �� .,. . . • _ • ` v 3 h • � Y � ., i I ` ,• . .. .... � Nb4�i � � � ,• � • �,'?a ••� � �. ..,'-: � �,, �U � U �� `7� .n . i . .�,�x,' , . Q i� 1 U _y,• � / �E U' f � t .��J C ♦ Q � �� ;�;! o _ � .�, ``. 1 ..a . tj q n � ''f �� 1 Q � '• . q r U. !:. . ,� e U ,f� . W � ��•w +e � �r � ,� �� » �'� �,o N �� . . . •e � K I � 7 �1 t ,;�, ��, �, . � �' 01 .l _ ' Q \ _ , , � • CV � � — � � J� h � �,', ; Q I � , � � �� y � �+ � I p _��Y �'�s ... . �s '..� ^ > , . . �;'�c —� .� ��• zC'-::`'.'>"':_,e � . � �: m�i� , _e � PJ?7. BeD � r � � � �� . . . �% ¢1? � � J' �''ar _ 10 y,�i+�."�'�v"� » :. �k?��• 1� ` '�O +. . � . � x ^ , .,. , .. . O t.; �� 4} ry4y . .;a. ., � ,��,1:I vl',. ♦� '^ I��' . . � f� f r Nt'n..,'1��( . �_r: Z � -,.k,y. �. ,. ' �'° ,�/ ' 0 �. . � . . , " ,� � � � �� ' � �� . • � � _ �;.�'1,'�.. r f, _` _� �� - M Y,A ,+�c'^r 1 . . ./ � � . l.. . r . ., ...�' . � r � , . ;' ' -. ' . � .. • (� ` � : — r i;. ..�. ,'d �, �� !O y ;:.Y .� ,:� '.r 0e�_ �+°e'�' . ' .�_m � � . �S �N,. � _..�•_ ��L � .,, � � . � ; �w -,�: . . �' . _iP1_�•8_ m ti�ii� I I�,�,:�" — o--��' _ �' GUIDE TO MAPPING UNITS � � For a full description of a mapping i.mit, read both the description of the mapping u�it and that of the soil series to xhich the mapping �it belongs. See table 6, page 70, for descriptions of woodland groups. Other informatian 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 thraugh 55. Estimated yields, table 7, page 79. Woodland Described Capability �it group Ma� on I symbol Mapping im it page Symbol Page Symbol AgB Aldeiw ood gravelly sandy loam, 0 to 6 percent slopes---------- 10 Ne-2 76 3d2 I AgC Alden,rood gravelly sandy loam, 6 to 15 percent slopes--------- 8 IVe-2 76 3d1 AgD A1 envoo gravelly sandy loam, 15 to 30 percent s opes-------- 10 VIe-2 78 3d1 AkF Aldeiwood and Kitsap soils, very steep------------------------ 10 VIIe-1 78 2d1 AmB Arents, Aldeiw ood material, 0 to 6 percent slopes 1/---------- 10 IVe-2 76 3d2 AmC Arents, A]deiwood material, 6 to 15 percent slopes 1/--------- 10 IVe-2 76 3d2 An Arents, Everett material 1/----------------------------------- 11 IVs-1 77 3f3 BeC Beausite gravelly sandy loam, 6 to 15 percent slopes---------- 11 IVe-2 76 3d2 BeD Besusite gravelly sandy loam, 15 to 30 percent slopes--------- 12 VIe-2 78 3d1 BeF Beausite gravelly sandy loam, 40 to 75 percent slopes--------- 12 VIIe-1 78 3d1 Bh Bellinghani silt loam------------------------------------------ 12 IIIw-2 76 3w2 Br Briscot silt loam--------------------------------------------- 13 IIw-2 75 3w1 Bu Buckley silt loam--------------------------------------------- 13 IIIw-2 76 4v►1 Cb Coastal beaches----------------------------------------------- 14 VIIIN-1 78 --- Ea Earlmont silt loam-------------------------------------------- 14 IIK-2 75 3vr2 Ed Edgewick fine sandy loam-----=-------------------------------- 15 IIIx-1 75 201 EvB Evereti gravelly sandy loam, 0 to 5 percent slopes------------ IS 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 Vle-1 77 3f2 i EwC �Everett-Aldeiwood gravelly sandy loams, 6 to 15 percent slopes----------------------------------------------------- 16 VIs-1 78 3f3 - \ Indianola loamy fine sand, � to 4 percent slapes-------------- 17 Ns-2 77 4s3 ' Indianola loamy fine sand, 4 to IS percent slopes----�-------- 16 IVs-2 77 4s3 ) Indianola loamy fine sand, 15 to 30 percent slopes------------ 17 VIe-1 76 4s2 KpB Kitsap silt loam, 2 to 8 percent slopes----------------------- 17 IIIe-1 75 2d2 KpC Kitsap silt loam, 8 Yo 15 percent slopes---------------------- 18 IVe-1 76 �d2 KpD Kitsap silt loam, 15 to 30 perceat slopes--------------------- 18 VIe-2 78 2d1 Ys C Klaus gravelly loamy sand, 6 to 15 percent slopes------------- 18 VIs-1 78 3f1 Ma Mixed alluvial land------------------------------------------- 18 VIw-2 78 201 NeC Neilton very gravelly loamy sand, 2 to IS percent slopes------ 19 YIs-1 78 3f3 Ng Newberg silt loam--------------------------------------------- 19 IIw-1 74 201 tac Nooksack silt loam-------------------------------------------- 20 IIw-1 74 201 No Noima sandy loam---------------------------------------------- 20 IIIw-3 76 3rr2 - Qr Orcas peat---------------------------------------------------- 21 VIIIw-1 78 --- Os Oridia silt loam---------------------------------------------- 21 IIrr-2 75 3w1 OvC Ovall gravelly loam, 0 to 15 percent slopes------------------- 22 IVe-2 76 3d1 OvD Ovall gravelly loam, 15 to 25 percent slopes------------------ 23 VIe-2 78 3d1 OvF Ovall gravelly loam, 40 to 75 perceni slopes------------------ 23 VIIe-1 78 3d1 Pc Pilchuck loamy fine sand-------------------------------------- 23 VIw-1 78 2s1 Pk Pilchuck fine sandy loan-------------------------------------- 23 IVw-2 76 2s1 Pu Puget silty clay loam----------------------------------------- 24 IIIw-2 76 3N2 % Puyallup fine sandy loam-------------------------------------- 24 IIw-1 74 201 RaC Ragnar fine sandy loam, 6 to 15 percent slopes---------------- 25 IVe-3 77 4s1 RaD Ragnar fine sandy loam, 15 to 25 percent slopes--------------- 26 VIe-2 78 4s1 RdC Ragnar-Indianola association, sloping: 1/---------------------- 26 -------- -- --- Ragnar soil--------------------------------------------- -- IVe-3 77 4s1 Indianola soil------------------------------------------- -- IVs-2 77 4s3 RdE Rag�ar-Indianola association, moderately steep: 1/------------ 26 -------- -- --- Ragnar soil--------------------------------------------- -- VIe-2 78 4s1 Indianola soil------------------------------------------- -- VIe-1 77 4s2 U. S. COVERNMENT PRIIi7ING OF£ICE:1973 O-168-266 ° I �� GUIDE TO MAPPING UNITS--Continued , Woodland I Described Capability imit group Map °n raibo2 Mapping imit page Symbol Page Symbol Re Renton silt loam------------------------------------------=- 26 IIIw-1 75 3w1 I� Riveiw ash--------------------------------------------------- 27 VIIIw-1 78 --- Sa Salal silt loam--------------------------------------------- 27 IIw-1 74 201 Sh Sammamish silt loam----------------------------------------- 27 IIw-2 75 3w1 ' Sk Seattle muck----------------------------------------------- 28 IIw-3 75 --- Sm Shalcar muck------------------------------------------------ 29 IIw-3 T5 --- Sn Si siit loam------------------------------------------------ 29 IIw-1 74 201 So Snohomish silt loam----------------------------------------- 30 IIw-2 75 3w2 j Sr Snohomish silt loam, thick surface variant------------------ 31 IIw-2 75 3w2 Su Sultan silt loam-------------------------------------------- 31 IIw-1 74 3w1 7� Tukwila muck------------------------------------------------ 32 IIw-3 75 --- UrUzban land-------------------'------------------------------ 33 -------- -- --- Wo Noodinville silt loam--------------------------------------- 33 IIw-2 75 3w2 � 1/ 7}►e composition of these u�its is more variable than that of the others in the Area, but it has been controlled xell enough to interpret for the expected use of the soils. 2.0 ANALYSIS OF SEVEN CORE REQUIREMENTS AND HEARING EXAMINER'S CONDITIONS Included within this section are the preliminary plat approval conditions and a narrative response �� describing how the conditions will be addressed prior to fina) piat recording. 2.1 The basic core requirements that govern this project have been listed below in a table that articulates how each of the core requirements have been addressed. These requirements come directly from the 1990 King County Surface Water Desigr► ManuaL DISCUSS10�1 OF CORF:REQUIREA9EN I S OF TIIE 1990 KING COUNTI'Sl'RFACE WATER DESIGY MANUAL CORE REQUIREhiENT HOW PROJEC"I'HAS ADDRESSED REQGIREMENT: No. 1: Discharge at the This project proposes discharge at the natural location in accordance with Natural Location Core Requirement No. l. Diversion of runoff is not proposed with the development of this project. No.2: Off-Site Analysis This drainage report incorporates a Level 1 Downstream Analysis located in the Appendix. Please refer to that document for fulfillment of this requirement. No.3: Flow Control This project is exempt from providing on-site peak rate runoff control, as il delineated on page I.2.3-5 of the 1990 King County Surface Water Design Manual, which states that on-site peak rate runoff control �vill not be � required for proposed projects if the proposed project site post developed peak runoff rates for the ]00-year/24-hour duration design storm event, as calcu(ated for each discharge location is found to be less than 0.� cfs, more than the peak runoff rate for the existing site conditions,which we meet. No.4: Conveyance System This project proposes a piped conveyance system designed wi�h sufficient capacit�� to convey and contain at a minimum the 25-year peak flow, assuming developed conditions for on-site conditions for tributary areas and existing conditions for any off-site tributary areas, all in accordance with the 1990 King County Surface Water Design Manual. No. 5: Temporary Erosion This project proposes to help control the transport of sediments to streams, and Sedimentation wetlands, lakes,and adjacent properties using the methods described in the Control 1990 King County Surface Water Design Manual, including establishing clearing limits, cover measures, and providing perimeter protection in the form of silt fences. ln addition, traffic area stabilization will be constructed in the form of a rock construction entrance, and a temporary sediment retention pond will be constructed near the proposed discharge point utilizing the bioswale area,prior to discharging from the site. No.6: Maintenance and All drainage facilities, including catch basins, conveyance systems, and Operations water quality facilities, will be located in the right-of-way of street improvements or in the tract or easement designated for that purpose, and will be maintained by the City of Renton in perpetuity. No.7: Bonds aod Liability This project concurs with all bonds and tiability requirements as dictated by the City of Renton. 1012R.01�.doc [f IP(��'tcPl 2.2 Summary of Hearing Examiner's Conditions Mapleton Short Plat City of Renton File No.LUA-02-158,SHPL-H Note: The following outline summarizes the Hearing Examiner's conditions for the preliminary plat approval, in italics, followed by a nanative response explaining how the Hearing Examiner's conditions have been met or will he met for this project. 1. 7'he applicant shall obtain a demolition permit and complete all necessan� inspections and approvals for the existing detached garage located on the property. The satisfaction of this requirement shall be subject to the review and approval of the Development Services Division prior to the recording of the short plat. Response: The applicant will obtain a demolition permit as required in this � condition prior to on-site construction. 2. The applicant shall sprinkler lots 1, 2 afid 3 in order to offset the sleep access road, ��I distance of the roadway to public streets, the number of lots, and to provirlr� �I adequate emergency protection. The satisfaction of this requirement shall bE� I� submit to the review and approval of the Develoj�r��r ��„�r�,�s ?�r,�i�ir>>r >>rtr�r r„ the issuance of Building Perjnits for lots 1, 2 and 3. Response: Notes have been added an the water c�� yi��,�� yui��ub �-, � � for Lots 1, 2 and 3. 3. A homeowner's association or maintenance agreement sha11 be creatf concurrently with the reeording of the short plat in order to eslablish maintenan� responsibilities for this development. A drafi of the document(s), if necessary, shu�i be submitted to the Ciry of Renton Devedopmertt Services Divisiort for review and approval by the City Attoniey and Property Services section prior to the recording of the short plat. Response: T'his condition will be met prior to the recording of the short plat. 4. The applieant shall place "No Parking"signage along the private roadway serving the development, as well as address identification signs at the entrance to the private street. The satisfaction of this requirement will be subjeet to the Development Services Division prior to recording of the short plat. Response: This condition will be met with the approval of the construction plans. S. The applicant shall pay the appropriate Transportation Mitigation Fee equal to $75.00 for each new daily trip associated with the project, witlz credit given for the existing residence, for an estimated total of be $4,306.50 (57.42 total trips x $75.00= $4,306.50). The Transponation Mitigation Fee shall be paid prior to the recording of the short plat. Response: The Transpor[ation Mitigation Fee will be paid prior to final plat approval. 10128.O15.doc(HPG/tep) 6. The applicant shall provide fencing along the top of any rockery exceeding 6 feet in height within the development site. The satisfaction of this requirement shall be subject to the review and approval of the Development Services Division prior to the recording of the short plat. Response: Rockeries exceeding 6 feet in height are not currently proposed on the construction plans. Therefore, fencing will noi be required as discussed in this condition. 7. The applicant sha11 comply with the recommendations contained within the Geotechnica! Engineering Study prepared by Earth Consultants Inc. dated May 2, 2002, including, but not limited to: 1) maintaining a minimum horizontal setback of 10 feet from the backside of the rockery for the placement of ftll and raising of site grades, building fou�tdations, and drainage improvements; 2) use of a geomembrane or soil liner to adequately seal the biofcltration swale; and, 3) with regard to site preparation, general earthwork, fzll slope placement, foundations, retaining walls, rockeries, drainage (specifically separately tight-lining roof dotivnspouts to discharge), excavations, slopes, utiliry support and backfill. The satisfaction of these requirements shall be subject to the review and approval of the Dei�elopment Services Division prior to the issuance of construction permits for the installation of required short plat improvements and/or prior to the issuance of building permits for the construction of individual homes on the created lots. Response: The construction plans currently reflect the requirements in the geotechnical study as listed. 8. The applicant shall install a silt fence along the doivn slope perimeter of the area that is to be disturbed. The silt fence shall be in place before clearing and grading is initiated, and shall be constructed in conformance with the specifications I presented in Section D.4.3.1 of the King Counry Surface Waier Design Manual, Appendix D. This will be required during the constructeon of both off-site and on-site improvements as well as building construction. Response: As shown on the temporary erosion control plans, a silt fence has been added as required under this condition. ', 9. Shallow drainage swales shall be constructed to intercept surface water flow and �, route the flow away from the construction area to a stabilized discharge point. Vegetation growth shall be established in the ditch by seeding or placing sod. Depending orz site grades, it may be necessary to line the ditch with rock to protect the ditch from erosion and to reduce flow rates. The design and construction of drainage swales shall conform to the specifications presented in Section 4.4.1 of the SWDM. Temporary pipe systems can also be used to convey storm water across the site. This will be required during the construction of both off-site and on-site improvements as well as building construction. Response: Interceptor swales have been shown to be constructed to route runoff into an erosion control facility as required. 10128.O15.doc(HPG/tep] 10. The project contractor shall perfonn daily review and maintenance of all erosion and sedimentation control measures at the site during the construction of both off- site and on-site improvements as well as building construction. Response: During construction, the contractor will perform daily review and maintenance of the erosion control facilities as required. I1. Weekly reports on the status and condition of the erosion control plan with any recommendations of change or revision to maintenance schedules or installation shall be submitted by the project Engineer of record to the public works inspector for the shorl plat construction. Certification of the installation, maintenance and proper rentoval of the erosion control facilities shall be required prior to recording of the plat. Response: Week}y reports will be prepared by the project engineer for this site during construction activities. 12. The applicant shall pay the appropriate Fire Mitigation Fee equal to $488.00 per new single family residence, with credit given for the existing residence, for an estimated total of $2,928.00 (6 new lots x $488.00 = $2,928.00). The Fire Mitigation Fee shall be paid prior to the recording of the short plat. Response: The Fire Mitigation Fee will be paid prior to final plat approval. 13. The applicant shall pay the appropriate Parks Mitigation Fee equal to$530.76 for each new single family home, with credit given for the e.risting residence, for an estimated total of $3,184.56 (6 new lots x $530.76 = $3,184.56). The Parks Mitigation Fee shall be paid prior to the recording of the short plat. Response: The Parks Mitigation Fee wiil be paid prior to final plat approval. ]4. The pipestem access to proposed lot I shall be paved to fifteen feet (I S'} and the length and the surface materials and strength shall be subject to review and approval of the Fire Department. Access to and from proposed lot 1 shall be restricted to the pipestem and the hammerhead access shall only be used by emergency vehicles for access to proposed lot I. Response: Additional paving that is necessary within the pipestem of Lot 1 is shown on the construction plans. 15. The dedications, if any, will have to be forwarded to tl2e City Cou�icil which otherwise does not review short plats. Response: This will be addressed at the time of the final plat review. !Ol'8.(ll�.�i�x �HPGhepl 3.0 OFF-SITE ANALYSIS A Level 1 Downstream Drainage Analysis was prepared for this project dated August 16, 2001. This analysis is included within this Technical Information Report (TIR) for reference. The downstream system was analyzed as discussed in the Level 1 drainage study, which meets the guidelines outlined in the 1990 King County Surface Water Design Manual. 10128.OI S.doc[HPG/tep] 4.� FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 4.1 Existing Site Hydrology Please review the Level 1 Drainage Study for an analysis of existing site hydrology. 4.2. Developed Site Hydrology The subject property will be developed as a 7-lot short plat including a curbed, paved street that dces not include sidewalks. A hammerhead turnaround will be incorporated as an emergency turnaround. A conveyance system including catch basins and underground storm drainage pipes will collect and convey the runoff from the roadway portion of the lots and the houses. The stormwater collected by the conveyance system will be routed to a biofiltration swale sized in accordance with the 1990 King County Surface Water Design Manual. The outiet from this swale will be routed through an underground conveyance pipe to the existing storm system within N.E. bth Court. 10128.OIS.doc[HPG/tepj 100-YEAR RUNOFF CALCULATIONS 8/24/Ol 10 : 36 :7 am Shareware Release page 1 PRITTIE SHORT PLAT JOB NO. 10128 WORKS4 FILE NO. 10128 .BSN --------------------------------------------------------------------- --------------------------------------------------------------------- BASIN SUMMARY BASIN ID: 100DEV NAME: 100 YR DEVELOPED SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 14 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 50 Acres 0 . 64 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . . 5 . 68 min 5 . 68 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 110 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 2000 TcReach - Shallow L: 200 . 00 ks:27 . 00 s : 0 . 1200 PEAK RATE: 0 . 80 cfs VOL: 0 . 30 Ac-ft TIME: 480 min _� BASIN ID: 100PRE NAME: 100 YR PREDEVELOPED SBUH METHODOLOGY TOTAL AREA. . . . . . . . 1 . 14 Acres BASEFLOWS : 0 . 00 cfs RAINFALL T'YPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 99 Acres 0 . 15 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . : 14 . 25 min 14 . 25 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 1270 PEAK RATE: 0 . 61 cf�s VOL: 0 . 25 Ac-ft TIME: 480 min BASIN ID: 2DE NAME: 2 YR DEVELOPED SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 14 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 .50 Acres 0 . 64 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . . 5 . 68 min 5 . 68 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 110 . 00 ns : 0 .1500 p2yr: 2 . 00 s : 0 . 2000 TcReach - Shallow L: 2�0 . 00 ks :27 . 00 s : 0 . 1200 PEAK RATE: 0 . 34 cfs VOL: 0 . 13 Ac-ft TIME: 480 min � 10� Y,E,��o iDE✓ M �N�n,S I D 0 Y� ��-E 1 S �._.,,E S S �rd�n.l Q.S L�S �. �'�'/11 �'. l�c Cn r�.�-� . iT-, � 1 . , . „ _ �QK,�t� � I � WATER QUALITY CALCULATIONS � � 8/15/O1 12 : 4 :4 am Shareware Release page 1 PRITTIE SHORT PLAT FILE #10128-BIO BIOSWRLE CALCS --------------------------------------------------------------------- --------------------------------------------------------------------- BASIN SUMMARY BASIN ID: A1 NAME: 640 2YR FOR BIOSWALE CALCS SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .15 Acres BASEFLOWS: 0 . 00 cfs � RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 1 . 28 inches AREA. . : 0 . 51 Acres 0 .64 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . : 5 _ 00 min 5 . 00 min ABSTR.ACTION COEFF: 0 .20 PEAK R.ATE: 0 ..23 cfs VOL: 0 . 07 Ac-ft TIME: 470 min BASIN ID. A2 NAME: 100YR POST-DEV ' SBUH METHODOLOGY ' TOTAL AREA. . . . . . . : 1 . 15 Acres BASEFLOWS: 0 . 00 cfs �� RAINFALL TYPE. . . . : KC24HR PERV IMP I PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 51 Acres 0 . 64 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 1 . 00 cfs VOL: 0 .30 Ac-ft TIME: 470 min 8/15/O1 12 :4 :4 am Shareware Release page 2 PRITTIE SHORT PLAT FILE #10128-BIO BIOSWALE CALCS --------------------------------------------------------------------- --------------------------------------------------------------------- HYDROGR.APH SUMMARY PEAK TIME VOLUME HYD RUNOFF OF OF Contrib NUM RATE PEAK HYDRO Area cfs min. cf\AcFt Acres --------------------------------------------- --------------------------------------------- 1 0 . 225 470 3135 cf 1 . 15 2 1 . 000 470 13080 Cf 1 . 15 � �D�ZS 200 LF SWALE FOR TREATMENT Worksheet for Trapezoidal Channei Project Description Project File c:lhaestad\fmw11012&bi.fm2 Worksheet BIOSWALE CALC'S Flow Element Trapezoidal Channel Method Manning's Formula Solve For Channel Depth Input Data Mannings Coefficient 0.350 Channel Slope 0.020000 ff/ft Left Side Slope 3.000000 H :V Right Side Slope 3.000000 H :V Bottom Width 2.00 ft Discharge 0.23 cfs Results Depth 0.33 ft Flow Area 0.99 ftz Wetted Perimeter 4.09 ft Top Width 3.98 ft < Critical Depth 0.07 ft Critical Slope 4.488863 ft/ft Veloc'ity 0.23 ft/s Velocity Head 0.84e-3 ft Specific Energy 0.33 ft Froude Number 0.08 Flow is subcritical. C . �� UC l 1Jl-a : � Z� x �w � �t�'R^f = ��t� '.� '1�� 'i� 50 � 3�t$ = l�.`�2 � �C�`P 08/15/01 FbwMaster v5.15 12:11:59 PM Haestad Methods,Inc. 37 Brookside Road Vlfaterbury,CT 06706 (203)755-1666 Page 1 of 1 � 60 LF SWALE FOR TREATMENT Worksheet for Trapezoidal Channel Project Description Project File c:lhaestad�fmw110128-bi.fm2 Worksheet BIOSWALE CALC'S Flow Element Trapezoidal Channel Method Manning's Formula Solve For Channel Depth Input Data Mannings Coefficient 0.350 Channel Slope 0.020000 ft/ft Left Side Slope 3.000000 H :V Right Side Slope 3.000000 H :V Bottom Width 12.53 ft Discharge 0.23 cfs Results Depth 0.12 ft Flow Area 1.58 ftz Wetted Perimeter 13.31 ft Top Width 13.27 ft � ��j ,Z(p� D� Critical Depth 0.02 ft Critical Slope 6.404239 ft/ft Velocity 0.15 ft/s Velocity Head 0.33e-3 ft Specific Energy 0.12 ft Froude Number 0.07 Flow is subcritical. I C�c �� s�r� (�Z�T� : , Zoo �c 3��1 g = 13,Zco lil �o � I �(�vt� 13.5 W�� 5�. � 08/15/01 FlowMaster v5.15 01:17:49 PM Haestad Methods,Inc. 37 Brookside Road Waterbury,CT 06708 (203)755-1666 Page 7 of 1 60 LF SWALE FOR CONVEYANCE Worksheet for Trapezoidal Channel Project Description Project File c:lhaestad�fmw110128-bi.fm2 Worksheet BIOSWALE CALC'S Flow Element Trapezoidal Channel Method Manning's Formula Solve For Channel Depth Input Data Mannings Coefficient 0.035 Channel Slope 0.020000 ft/ft Left Side Stope 3.000000 H :V Right Side Slope 3.000000 H :V Bottom Width 12.53 ft Discharge 1.00 cfs -E-- ��OY� �$T-�£lJ Resutts Depth 0.07 ft F- (..£SS '(�'�1�T1 (.D� bK Flow Area 0.95 ft2 = Wetted Perimeter 13.00 ft Top Width 12.98 ft Critical Depth 0.06 ft Critical Slope 0.046400 ft/ft Velocity 1.05 ft/s j Velocity Head 0.02 ft ' Specific Energy 0.09 ft Froude Number 0.68 ' Flow is subcritical. OS/15/01 FlowMaster v5.t5 01:18:05 PM Haestad Methods,Inc. 37 Brookside Road Waterbury,CT 06708 (203)755-1666 Page 1 ot 1 _ _ _ __ _ _ 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN Enclosed are calculations that were necessary for sizing the conveyance system for this project. The rational method and Mannings formula were used for sizing each of the pipes. The conveyance pipes have been sized in accordance with the 1990 King County Surface Water Design Manual. The intent of the pipe system is to route the runoff from the roadways including the houses and contributing areas from yards eventually to the biofiltration swale area. 10128.O15.doc[HPG/tep) 6.0 SPECIAL REPORTS AND STUDIES 6.1 Level 1 Downstream Analysis Report Dated August 16,2001 6.2 Geotechnical Engineering Study by Earth Consultants Dated May 2, 2002 I 6.1 LEVEL 1 DOWNSTREAM ANALYSIS REPORT DATED AUGUST 16, 2001 DRAINAGE REPORT AND LEVEL 1 DOWNSTREAM ANALYSIS Proposed Prittie Short Plat NEC - N.E. 6th Court and Blaine Court N.E. Renton, Washington ��RY JACpe g ��'�� Prepared for: ��Fw��N� Michael J. Prittie ;e z 8910 8th Avenue N.E. � Seattle, WA 98115 ,rr ��7 �� S NA EXPiRES 1 �1 OI �/ August 16, 2001 Our Job No. 10128 ¢�1-�A C�S' m� �r �Z ( �`_ CIVIL ENGINEERING, LAND PLANNING,SURVEYING, ENVIRONMENTAL SERVICES � 18215 72ND AVENUE SOUTH, KENT,WA 98032 • (425)251-6222 . (425)251-8782 FAx y,�G ��,�� , www.barghausen.com <r��6'N�{��` TABLE OF CONTENTS 1.0 INTRODUCTION AND GENERAL INFORMATION 2.0 ANALYSIS OF THE SEVEN CORE REQiJIREMENTS 3.0 ANALYSIS OF TWELVE SPECIAL REQiJIlZEMENTS APPENDIX APPENDIX "A" TECHNICAL INFORMATION REPORT WORKSHEET APPENDIX "B" WATER QUALTTY AND FLOW CONTROL CALCULATIONS APPENDIX "C" LEVEL 1 DOWNSTREAM ANALYSIS � � _ � �- f � 1.0 INTRODUCTION AND GENERAL INFORMATION 1.0 IN1`KODUCTION ANll GENEI�L INFOK��1A'I'IUN The proposed Prittie short plat is located in a portion of the n�rth�a�t yuart�r�C th� s��uth�ast yu.ut�r�;f Section 8, Township 23 North, Range 5 East, Willamette Meridian, City of Renton, King Count}. Washington. More particularly,it is located on the northeast corner of N.E.6th Court and Blaine Court N.E. See Exhibit "A," Vieiniry I41ap, within Appendix "C" of this report, the Level 1 Downstream Analysis. The existing topography of the site is fairly steep in nature,with slopes up to 14 percent over the majority of the site. The site is covered with grass for the most part,except for an existing home with associated outbuildings and a private drive serving the home. The proposal for this development is to keep the existing home in its natural state;however,the existing home is served by a driveway to the north of the site,which will be abandoned on site and a new driveway constructed from the southwest corner into the central portion of the property to serve seven lots. There are rockeries along the full western property line of the site, as well as the central portion and eas[ern property line of the site. This project proposes a private road internal to the site, connecting to N.E. 6th Court. There is an existing storm drainage collection and conveyance system in N.E. 6th Court,which drains west to the collection system in Sunset Baulevard. Ultimately,the site's runoff w�ill drain into the N.E. 6th Court drainage system after routing on-site runoff through a biofiltration swale prior to discharging from the site_ This project is exempt from providing detention on site,due to the fact that the difference in the pre-and post-developed I00-year/24-hour storm events is less than 0.5 cubic feet per second. Please see the enclosed caIculations within Appendix "B"of this report. �oi2s.00s �rn��act�r�l 2.0 ANALYSIS OF THE SEVEN CORE REQUIREMENTS 2.0 ANALYSIS OF THE SEVEN CORE REQUIREMENTS Core Requirement No.l-Discharge at the Natural Location: The discharge from a proposed project site must occur at the natural location. Response: This project proposes discharge at the naturaI location in accordance�vith Core Requirement No. 1. Diversion of runoff is not proposed with the development of this project. Core Requirement No. 2 - Off-Site Analysis: All proposed projects must identify the upstream tributary drainage area and perform a downstream analysis. Levels of analysis required depend upon i problems identifed or predicted. At a minintum, a Level I Analysis rnust be submitted with the initial pennit application. Response: This drainage report incorporates a Level 1 Downstream Analysis as Appendix"C." Please � refer to that document for fulfillment of this requirement. Core Requirement No.3-Flow Control: Proposed projects must provide runoff control to limit the developed condition's peak rates of runoff to the pre-development peak rates for specific design storm events, based on the runoff from defrned e.risting site conditions and install biof Itration measures. Response: This project is exempt from providing on-site peak rate runoff control, as delineated on page 1.2.3-5 �f the 1990 King County, Washington Surface �Vater Design Manual, which states [hat on-site peak rate runoff control will not be required for proposed projects if the proposed project site post-developed peak runoff rates for the 100-year/24-hour duration design storm event,as calculated for � each discharge location is found to be less than 0.5 cfs, more than the peak runoff rate for the existing site conditions, which we meet. Core Requirement No.4-Conveyance System: All conveyance systems for proposed projects must he analyzed,designed,and constructed for existing tributary•off-site runoff and developed on-site runoff from the proposed project. Response: This project proposes that the new pipe systems shall be designed with sufficient capacity to convey and contain at a minimum the 25-year peak flow,assuming developed conditions for on-site conditions for tributary areas and existing conditions for any off-site tributary areas, all in accordance with the 1990 King County, Washington Surface Water Design Manual. Core Reguirement No.S-Temporary Erosion and Sedimentation Control: All projects that require engineered drainage plans shall provide temporarj�erosion and sedimentation control measures that minimize the transpon of sediments to drainage facilities, water resources, and adjacent properties. Response: This project proposes to prevent the transport of sediments to streams,wedands,lakes,and adjacen[properties using the methods described in the 1990 King County, Washington Surface Water Design Manual, including establishing clearing limits, cover measures, and providing perimeter protection in the form of silt fences. In addition,traffic area stabilization will be constructed in the form of a rock construction entrance, and a temporary sedimeni retention pond will be constructed at the proposed discharge point from the temporary construction site prior to discharge of runoff from the site. 10128.005 [1PJ/ath/bq] Core Requirement No. 6 - A�Iaintenance and Operations: Maintenance of all drainage facilities constructed or modified by a proposed project is the responsibility of the project owner, except the City of Renton may assume maintenance of drainage facilities constructed for formal plat subdivisions, planned unit developments, and some short plat subdivisions two years after construction approval. Response: All drainage facilities, including catch basins, conveyance systems, detention, and water quality facilities, will be located in the right-of-way of street improvements or in the tract or easement designated for that purpose, and will be maintained by the City of Renton in perpetuity. Core Requirement No.7-Bonds and Liability: All drainage facilities for the proposed projects must be constructed in conformance with the bond and liability requirements of the City of Renton. Response: This project concurs with all bonds and liability requirements as dictated by the City of Renton. 101 Z8.005 �1P1/ath/bq) 3.0 :�N:�I,��IS UI�� 'l�Ill�; "1'ti�'I�L�`I; SP1;(_'I.��L IZI:(,�UIREI�II;N'[,S 3.0 ANALYSIS OF TWELVE SPECIAL REQUIREMENTS Special Requirement No. l -Critical Drainage Areas: If a proposed project lies within a designatecl critical drainage area, as indicated on critical drainage area maps, then the proposed project drainage review and engineering plans shall be prepared in accordance x�ith the special critical drainage area requirements that have been formally adopted by publie rule. Response: The proposed project site does not lie within a critical drainage area. Special Requirement No. 2 - Compliance with an E�sting 14Zaster Drainage Plan: If a proposed project lies within an area covered by an approved master drainage plan,as listed in the City ofRenton � Division Permits Center, then the proposed project's drainage review and engineering plan shall be ', prepared in accordance with any special requirements of the master drainage plan. I Response: The project site does not lie within an existing master drainage plan. Special Requirement No.3-Conditions Requiring a Master Drainage Plan: If a proposed projecr is a master plan development,as described in an adopted eommunity plan,or is a subdivision or planned use development that will eventually have more than 100 single family residential lots, or is a commercial development or planned unit devedopment that will evenhcally constn�ct more than 50 acres of impervious surface, or will clear an area of more than 500 acres within a contiguous drainage area subbasin, then a master drainage plan must be prepared. Response: The site does not meet any of the conditions requiring a master drainage plan. Special Requirement No.4-Adopted Basin and Community PIans: If a proposed project lies within an area with an adopted basin or community plan, as listed in the City of Renton Division Permits Center,then a proposed project drainage review and engineering plan shall be prepared in conformance x�ith the special requirements of the adopted basin plan or community plan. Response: This project site does not lie within an adopted basin or community plan area. Special Reqairement No.5-Special Water Quality Controls: If any threshold area of the proposed project contains more than one aere of new impervious surfaee that will be subjeet to vehieular use or storage of chemieals and proposes direct discharge of runoff to regional faeilities,reeeiving water,lake, wetland, or closed depression without on-site peak rate runoff control or proposes discharge of runof.j' through overland flow, or on-site infiltration into a Class I or II Stream, or a Class I Wetland within a I-mile radius downstream from the project site, then the threshold discharge area shall have a wetpond meeting the standards of rhe City of Renron employed to treat a project's runoff prior to the discharge from the site. Response: This project proposes a biofiltration swale as the methodology of storm water quality treatment. There will be less than one acre of new impervious surface, therefore, the threshold of this requirement is not met. Special Requirement No. 6 - Coalescing Plate Oil/Water Separator: If a proposed project wiil construct more tharz 5 acres of impen>ious surfaee in any threshold discharge area, that will be subject to petroleum storage or transfer, or high vehicular use or heavy equipment use for storage or 10128.005 [JPJ/ath/bq� maintenance, then a coalescing plate or eguivalent oil/water separator shall be employed in the threshold discharge area to treat rhe project's runoff prior to treatment by a wet pond, wet vault, or water qualiry swale. Response: This project does not meet the threshold of this requirement,therefore,no coalescing plate oillwater separator is required. Special Requirement No.7 - Closed Depression: If a proposed project will discharge runo}f to an existing closed depression that has greater than S,000 sguare feet of water surface at overflow elevation, then the project must meet the requirements of a closed depression. Response: This project dces not discharge to a closed depression in any of its downstream drainage course. Special Requirement No.8-Use of Lakes,Wetlands,or Closed Depressions for Peak Rate Runoff Control: If a project proposes to use a lake,wetland,or closed depression for peak rate runofJ`control, consistent with Core Requirement No. 3,or use a lake, wetland, or closed depression to receive a direct discharge consistent with an exemption from Core Requirement No.3,or increases the volume of runofJ`' to an off-site closed depression, then the project must meet all of the requirements of the Sensitive Areas Ordinance and n�les for such including water quality controls consistent with Special Requirement No.S and observe limits on any increases to the floodplain as described in the 1990 King County, Washington Surface Water Design Manual. I Response: This project dces not plan the use of a lake,wetland,or closed depression for peak rate runoff con trol. Special Requirement No.9-Delineation of 100-Year Floodplain: If a proposed project contains or abuts a stream, lake, wetland, or closed depression,or if other King County regulations require a study of flood hazards,then the 1 DO-yearJloodplain boundaries,based on an approved flood hazard study as described in the 1990 King Counry, Washington Surface Water Design Manual, shall be delineated on the site improvement plans and profiles, and on any final subdivision maps prepared for the proposed development. Response: This project does not contain or abut a sveam, lake> wetland,or closed depression. Special Requirement No. 10-Flood Protection Facilities for Class I and II Streams: If a proposed project contains or abuts a Class 1 or 11 Stream that has an existing flood protection facility, such as a levee, revetment, or berm, or proposes to construct or modify an existing}lood protection facility, then the flood protection shall be analyzed and/or designed as described in the 1990 King County, Washington Surface Water Design Manual to demonstrate conformance with the Federal Emergency Management Administration regulations. Response: This project dces not contain or abut a Class I or II Stream, and is not proposing to modify an existing flood protection facility, therefore, no flood protection facility needs to be analyzed and/or designed as described in the 1990 King County, Washington Surface Water Design Manual. Special Requirement No. 11 -Technical Analysis and Report: If a project proposes to construct a pond or an inftltration system within 200 feet from the top of u steep slope, or on u slope with a gradient 10128.005 [JPJ/ath/bq] steeper than 15 percent,or using a berm higher than 6 feet, or modify existing flood protection facilities, then a geotechnical analysis and report shall be prepared and stamped by a geotechnical or professional civil engineer, and shall address at minimum the analysis described in the 1990 King County, Washington Surface Water Design Manual. Response: This project does not meet any of the threshold requirements for Special Requirement No. l l. Special Requirement No.12-Soils Analysis and Report: If the soils underlying a proposed project have not been mapped or if the existing soil maps are in error, or not of a sufficient resolution to allow a proper engineering analysis of the proposed site to be performed, then a soils analysis and report shall be prepared and stamped by a professional civil engineer wirh expertise in soils to verify andlor map the underlying soils by addressing the minimum as described in the 1990 King County, Washington Surface Water Design Manual. Response: A geotechnical engineering study has not been prepared for this project site,as this submittal �', requirement has been waived by the City of Renton. ' ,I � 10128.005 []P]/ath/bqj � � A � W a a � APPENDIX "A" TECHNICAL INFORMATION REPORT WORKSHEET King County Department of Development and Environmental Services TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND Part 2 PROJECT LOCAT{ON AND PROJECT ENGINEER DESCRIPTION Project Owner Michael J. Prittie Project Name Address 8910 8th Avenue N.E., Seattle,WA Smith Short Pfat 98115 Location � Phone (206)730-1557 Township 23 North Project Engineer Hal Grubb Range 5 East Company Barqhausen Consultinq Engineers, Inc. Southeast 1/4 Section 8 I Address/Phone 18215-72nd Avenue South Kent, Washinqton 98032/(425)251-6222 Part 3 TYPE OF PERMfT Part 4 OTHER REVIEWS AND PERMITS APPLICATION 0 Subdivision HPA ❑ DFW HPA ❑ Shoreline Management ■ Short Subdivision 0 COE 404 ■ Rockery O Grading ❑ DOE Dam Safety O Structural Vaults ❑ Commercial 0 FEMA Floodplain ❑ Other 0 Other ❑ COE Wetlands Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community Renton Drainage Basin Lake Washinqton Part 6 SITE CHARACTERISTICS ❑ River ❑ Floodplain O Stream ❑ Wetlands ❑ Critical Stream Reach ❑ Seeps/Springs O Depressions/Swales ❑ High Groundwater Table ❑ Lake ❑ Groundwater Recharge ❑ Steep Slopes O Other 10128A04 [JPJ/athJ Part 7 SOILS Soil Type Slopes Erosion Potential Erosive Velocities AqC, Alderwood 6 to 15 0 Additional Sheets Attached Part 8 DEVELOPMENT LIMfTATIONS REFERENCE LIMITATION/SITE CONSTRAINT ■ Ch. 4- Downstream Anaiysis ❑ I ❑ ❑ ❑Additional Sheets Attached ' Part 9 ESC REQUfREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC RE(�UIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION ■ Sedimentation Facilities ■ Stabilize Exposed Surface � ■ Stabilized Construction Entrance ■ Remove and Restore Temporary ESC Facilities ■ Perimeter Runoff Control ■ Clean and Remove all Silt and Debris 0 Clearing and Grading Restrictions ■ Ensure Operation of Permanent Facilities ■ Cover Practices 0 Flag Limits of SAO and open space preservation ■ Construction Sequence areas O Other ❑ Other Part 10 SURFACE WATER SYSTEM ■ Grass Lined Channel 0 Tank ❑ Infiltration Method of Analysis ■ Pipe System O Vault ❑ Depression SBUH 0 Open Channel 0 Energy Dissipater ❑ Flow Dispersal Compensation/Mitigation O Dry Pond O Wetland 0 Waiver of Eliminated Site Storage O Wet Pond O Stream ❑ Regional Detention Brief Description of System Operation Catch basin collection and pipe convevance system to biofiltration swale prior to discharqe to existinq City svstem in N.E. 6th Court Facility Related Site Limitations Reference Facility Limitation 10128.004 [JP]/ath] Part 11 STRUCTURAL ANALYSIS Part 12 EASEMENTS/TRACTS O Cast in Place Vault ■ Drainage Easement 0 Retaining Wall 0 Access Easement ■ Rockery>4' High ❑ Native Growth Protection Easement 0 Structural on Steep Slope ■ Tract 0 Other ❑ Other Part 13 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attachments. To the best of my knowledge the information provided here is accurate. � � Signed/Date 10128_(Hki (JPJ/athJ APPENDIX "B" WATER QUALITY AND FLOW CONTROL CALCULATIONS 8/24/O1 10 : 36 : 7 am Shareware Release page 1 PRITTIE SHORT PLAT ' JOB NO. 10128 WORKS4 FILE NO. 10128 .BSN --------------------------------------------------------------------- ------------------------------------------------------------------ BASIN SUMMARY , BASIN ID: 100DEV NAME: 100 YR DEVELOPED SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 14 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 50 Acres 0 . 64 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . . 5 . 68 min 5 . 68 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 11d . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 _2000 TcReach - Shallow L: 200 . 00 ks :27 . 00 s : 0 . 1200 PEAK R.ATE: 0 . 80 cfs VOL: 0 . 30 Ac-ft TIME: 480 min _� BASIN ID: 100PRE NAME: 100 YR PREDEVELOPED SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 14 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 _ 99 Acres 0 . 15 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . : 14 _25 min 14 .25 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 1270 � PEAK RATE: 0 . 61 cf� VOL: 0 . 25 Ac-ft TIME: 480 min BASIN ID: 2DEV NAME: 2 YR DEVELOPED SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 14 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElR PERV IMP PRECIPITATION. . . . : 2 . �0 inches AREA. . : 0 . 50 Acres 0 . 64 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . OQ TC. . . . . 5 .68 min 5 . 68 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 110 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 .2000 TcReach - Shallow L: 200 . 00 ks :27 . 00 s : 0 . 1200 PEAK RATE: 0 .34 cfs VOL: 0 . 13 Ac-ft TIME: 480 min !0 o Y,Erg-� �DE✓ M �N�5 loo Y� �� /S �--,�5 S �nr�•J 0•S L�S �, F�F F�.E�tlL E, . SO �.��E.✓�--i Dn! �S �l0 7- �EQ��p , 200 foot swale for biofiltration Worksheet for Trapezoidal Channel Project Description Project Fife c:lhaestadlfmwlprojectl.fm2 WorksMeet , Smith Short Plat Flow Element Trapezoidal Channel Method Manning's Formula Solve For Bottom Width fnput Data Mannings Coefficient 0.350 `' Channel Slope 0.020Q00 fUft - Depth 0.33 ft Left Side S{ope 3.000000 H : V Right Side Slope 3.000000 H : V Discharge 0.34 cfs Results Bottom Width 3.21 ft Flow Area 1.38 ft2 Wetted Perimeter 5.29 ft Top Width 5.19 ft �—� �Q ' � �, � 5 ' = 1 ��j� S� Critical Depth 0.07 ft Critical Slope 4.475732 ft/ft Velocity 0.25 ft/s � Q �� / Velocity Head 0.94e-3 ft 6O ^ � �, � j fl P L✓l��^l Specific Energy 0.33 ft Froude Number 0.08 , Flow is subcriticaL t,:,� � i ..�,�r� ,�:.,. . ��, 60 foot swale for biofiltration Worksheet for Trapezoidal Channel Project Description Project File c:lhaestadlfmwlprojectl.fm2 , Worksheet Smi1h Short Plat Flow Element Trapezoidal Channel Method Manning's Formula Solve For Channel Depth Input Data Mannings Coefficient 0.350 I, Channel Slope 0.020000 fUft �, Left Side Stope 3.000000 H : V Right Side Slope 3.000000 H : V� ��,� ` �O � �� M i Bottom Width 16.50 ft - «� Discharge 0.34 cfs w �� I Results Depth 0.13 ft Flow Area 2.23 ft2 Wetted Perimeter 17.33 ft I Top Width 17.29 ft Critical Depth 0.02 ft Critical Slope 6.238245 ft/ft Velocity 0.15 ft/s Velocity Head 0.36e-3 ft Specific Energy 0.13 ft Froude Number 0.08 Flow is subcritica{. � �_ , i i 'j. ! I i � F � I � �,_ 1� �_,/� 08/24/O1 FlowMaster v5.15 11:00:39 AM Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 (203)755-1666 Page 1 of 1 60 foot swale for conveyance Worksheet for Trapezoidal Channel Project Description Project File c:lhaestadlfmwiprojectl.fm2 Worksheet Smith Short Plat Flow Element Trapezoidal Channel Method Manning's Formula Solve For Channel Depth Input Data Mannings Coefficient 0.027 Channel Slope 0.020000 ft/tt Left Side Slope 3.000000 H : V Right Side Slope 3.000000 H : V Bottom Width 16.50 ft Discharge 0.80 cfs -�—" �� +�. DIS�1v''0'�6� Results Depth 0.05 ft Flow Area 0.79 ft2 Wetted Perimeter 16.80 ft Top Width 16.78 ft Critical Depth 0.04 ft ' Critical Slope 0.030732 ft/ft Velocity 1.01 ft/s Velocity Head 0.02 fi Specific Energy 0.06 ft Froude Number 0.82 Flow is subcritical. 08/27lOt FlowMaster v5.t5 01:49:22 PM Haestad hlethods. Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 Page t of 1 APPENDIX "C" LEVEL 1 DOWNSTREAM ANALYSIS LEVEL 1 DOWNSTREAM ANALYSIS Proposed Smith Short Plat NEC - N.E. 6th Court and Blaine Court N.E. Renton, Washington g'�� Prepared for: ��RY �A�Des Michael J. Prittie '��°�w��,, 8910 8th Avenue N.E. � Seattle, Washington 98115 �r � ? 9A � S� L�,w EY.PIRES �o��o�p2� August 16, 2001 Our Job No. 10128 �GHA{�� f �� CIVIL ENGINEER{NG,LAND PLANNING,SURVEYING, ENVIRONMENTAL SERVICES 1 H215 72ND AVENUE SOUTH,KENT,WA 98032 • (425)251-6222 • (425)251-8782 FAx ' www.barghausen.com � . �.,,, u �s�G �I/U�* gz <r,M��G,�,��` TABLE OF CONTENTS 1.0 PROJECT OVERVIEW 2.0 UPSTREAM DRAINAGE ANALYSIS 3.0 DOWNSTREAM DRAINAGE ANALYSIS AND PROBLEM SCREENIlVG 4.0 RESOURCE REVIEW 4.1 Basin Reconnaissance Summary Report 4.2 Floodplain and Floodway FEMA Maps 4.3 Other Off-Site Analysis Reports 5.0 SENSITIVE AREAS MAP FOLIOS 6.0 SWM DNISION DRAINAGE INVESTIGATION SECTION PROBLEM MAPS 7.0 WETLAND INVENTORY MAPS 8.0 CONCLUSION EXHIBITS EXHIBTI'"A" VICINTTY MAP EXI-IIBIT "B" DOWNSTREAM DRA.INAGE MAP EXHIBTI'"C" OFF-STI'E ANALYSIS DRAINAGE SYST'EM TABLE EXHIBIT "D" FEMA MAP EXHIBIT "E" SENSITNE AREAS MAP FOLIOS I EX�IIBTI'"F" UPSTREAM BASIN MAP i EXHIBIT"G" SCS SOII,S I�i�P EXHIBIT "H" ASSESSOR'S I�lAP EXHIBIT"I" BASIN RECONNAISSANCE SLTMMARY REPORT � w � � � w � � � U w � 0 � � O � 1.0 PROJECT OVERVIEW The proposed Smith short plat is a preliminary plat of approximately 1.18 acres, with seven lots and associated street improvements to N.E. 6th Court. The proposed project is located within a portion of the northeast quarter of the southeast quarter of Section 8,Township 23 North,Range 5 East,Willamette Meridian, City of Renton,King County,Washington. A more localized description is that the project site is located at the northeast comer of N.E.6th Court and Blaine Court N.E.,within the City of Renton, east of I-405 and Sunset Boulevard. The enclosed Vicinity Map,E�ibit"A,"depicts Ehe approacimate location of the proposed site. T'he existing topography of the site has slopes ranging up to 15 percent. "There is an existing house and two outbuildings located on the proposed development at this time. The driveway serves the existing house,and the remainder of the proposed site is covered with grass. There are rockeries located along the western and eastern property lines of the site,as well as along the east side of the existing house which separates the driveway from the upper portion of the site. There are no wetlands located on this site. The site topography is such that it slopes,for the most part,in a northeast ro south„�esterly direction,concentrating in N.E.6th Court,where it ultimately collects in the conveyance system in Sunset Boulevard and is conveyed in a southerly direction. . ,_ ,_,. ... , 2.0 UPSTREAM DRAINAGE ANALYSIS 2.0 UPSTREAhi DRAINAGE ANALYSIS Based on the 1 inch equals 200 feet topographic map provided by the City of Renton and our site visit, it appears that there is upstream flow onto and through the site. A small area of land, approacimately 0.875 acres,lying east of the project site, and west of Blaine Ville Avenue N.E.flows onto and through the site. The upstream basin is fully developed,with existing residences and backyards. Please refer to the upstream basin map for a further description of the ugstream basin_ When the proposed project site is developed,a french drain or swale will be constructed along the eastern and northem property fines to convey runoff around the project site, and ultimately tie runoff into the existing storm drainage system sunounding the project site so that no upstream runoff will be collected in the on-site pipe conveyance system. No upstream runoff will impact any of the on-site homes. 10128.006 []PJlath] 3.0 DOWNSTREAM DRAINAGE ANALYSIS AND PROBLEM SCREENING 3.0 DOWNSTREAM DRAINAGE ANALYSIS AND PROBLEM SCREENING The Off-site Analysis Drainage System Table lists the downstream conveyance from the site (see Exhibit "C"). Runoff from the project site sheetflows off of the southwest property comer into the right-of-way of N.E. 6th Court, where it is collected either in a catch basin at the comer of the site or sheetflows down the street toward Sunset Boulevard for approximately I 1 S feet,where it is collected in a catch basin conveyance system. From there it is conveyed in a southerly direction within a pipe conveyance system in Sunset Boulevard,ultimately dischazging into the right-of-way of I-405,and then underneath I-405 ihrough 30-inch CMP culvert. From there it dischazges to a wetland swale that flows in a northern direction between the railroad tracks and I-405, ulUmately discharging into Lake Washington approximately one mile from the site. Please refer to the Off-Site Analysis Drainage System Table for a complete description of this downstream drainage course. 10128.006 [JPJ/ath] � w � ►7 � w � x � 0 � � 0 � 4A RESOURCE REVIEW The following is a description of each resource reviewed in prepazation of this Level 1 Drainage Analysis: 4.1 Basin Reconnaissance Summary Report The site is Iocated in the Lake Washington Basin and a summary report is enclosed. There were no collection points or proposed projects within the tributary basin that the site is located in. Please refer to Exhibit"I." 4.2 Floodplain and Floodway FEMA Maps Please see the enclosed FEMA Map utilized for this analysis, Panel No. 977 of 1,725, Map No. 53033C0977 F,revised May 16, 1995. As indicated by this map, the proposed project site dces not lie within a floodway or floodplain. Please refer to E�chibit"D." 4.3 Other Off-Site Analysis Reports A review of the enclosed Basin Summary Report and a site investigation were conducted for analysis in preparation of this Level I Drainage Report. The United States Department of Agriculture Soils Conservation Service Map is also provided. The soils on this site are mapped as AgC Alderwood gravelly sandy loam at 6 to 15 percent slopes. ]0128.006 [JPJ1ath] 5.0 SENSITIVE AREAS MAP FOLIOS 5.0 SENSITIVE AREAS MAP FOLIOS Based on a review of the King County Sensitive Areas Map Foiios, it was found that the subject site discharges into Lake Washington. However,the site is not located in any mapped sensitive area. �o�2a.006 ��iam� i 6.0 SWM DIVISION DRAINAGE INVESTIGATION SECTION PROBLEM MAPS , ; � 6.0 SWM DIVISION DRAINAGE INVESTIGATION SECTION PROBLEM MAPS Since this project site is located within the City of Renton, and not in unincorporated King County,no I drainage complaints are available for review for the downstream drainage course from this site. There w�ere no problems associated with the downstream drainage course that were visible during the morning of the August 14, 2001, downstream analysis. The sky was overcast, and the temperature was approximately 60 degrees. There was no evidence of erosion, sedimentation, or flooding occurring in ! any of the downstream azeas that were followed in this downstream analysis, therefore, if the City indicates that further analysis is warranted due to complaints they receive from the property owners do��nsiream from the site, then further analysis will be performed. ]0128.006 []PUath) 7.0 WETLAND INVENTORY MAPS 7.0 WETLAND INVENTORY MAPS Review of the King County Sensitive Areas Map Folios dces not depict any wetlands within or contiguous with this property. The only wedand found in the downstream drainage caurse were the cattails growing in the channel between the railroad tracks and I-405. 10128.006 [JPI/ath) C/1 Z � � C/� ►� h� U Z O V 0 00 8.0 CONCLUSIONS The azea downstream from the project site appears to be very adequate at conve}�ng runoff from the project site and the development will have minimal impact,if any at all,on the do«�nstream conveyance system. Therefore, this project is deveiopable as proposed. 10128.006 [JP3/athj � E"� � � h--i � J� w _- _ EXHIBIT "A" VICINITY MAP � � � �' � / _... yi�ST � BOTH P� SE �'�� ,S aon�.v�s � � � � � x ��` ,� `J l�ti�`� . B 7H F V� �'� m �1 e 787 �' AV S � a�� I� J � R �':�� 815T vk ,� v$ ^�'`oF v `` v, e N a�w 5h� �I` ��, � `� W 1a os v '; "'I tj� � 79 H""� AV 5 N �N u+ W s y �,Q p ,�� n� ^ � � . m C 12000 � �'�-�i � tn �b7* ,:'�oJ' .`r ��' .C�� W n� N m O � p � _ � eorN �v_- s eaTM� �v s Ss�� , s.., + f�'r � �� }, �N e� rH AV SE 1�""�-`"+ ..� � �Mc.� '4` ::.N '��I y . �:' N N, 1. ,•.C �,��p.� ,�� 's� $ ;\�� _� '-�l� go � PL ,E <� _ " � 3 � � ��" tDn 8��N� AV a�°,�� VL'.. �� e15 � S 4'� `' � . `�' 3S n5a �Q s 5T +(7 �� ry ,., f Io ... . .� ' S s �T� � . �f'�b c �. � '^�c�� m 0/ C � � ^� �'.. t"i,�'jh.J .o�.,s, ��.r .'�P� � `ptin,S AV S � � � � � 4TH �� q � S �� $ ' � �!� �1 p �>" V'"5 C � I 90 N ,,.,1 30 ,,., 11000 . W �` � O8 TH -�i tn v` $ w Ol . m0� G' J, � �'�'r' ..� S m �� `86TH CT S � � v g N ~� � . �� . _ q�q� �� m ,/ s `^.87TN AV� � -' '' ,'- `-� , ,o��0y �,.a,K, ia� � J7 1 w uxo.� = � S m�`�, d 1ST6 ,� � My �v � y L.( -�i: "� eeTM�v" � N16 y � Y � ��t o Z. .;`: �n �ATlO N t� m .� O ',� �v .� v 5 . ' ., � �� 92N AV 9]w 00 �N7 �_ x �.,��- � � a � �> 9QH�V S �1 '�: ��1. i i�.i i �� DO < �av.u._.__��---; � ,� a3�Ia -- �' ' ..� � .Y� ^�«,:a;e 3�' 1.1. �N =1 ) �� ., z � au' � , � - � � � � � � r. --� : � �� - m � � r. � •� �`d �� //�� '\ � ,,^..�—� i S p g= -� �� D ! � �� , � BUR 8 `�^.,.ti-- ^D � V N '� n �� \`\ . ~ �iel z z x = � \� \ \ �\�� :: i x - � '�� i � � � � � �' � � wt s au w Z �� _�l� �. `;-,,.. ; PARK AV N � . � �� /Byf� . ��a �� x � \ �. �,��' . . . Z,NS�M:I�� I � � � PAR � � � AV N = RDEN P,p ��y, �Q�,�� P�RK P�,y ,y, 280 � 00 3600 g �� • Q N A �, 17 ✓.1 -'^. �EA0.�y Q i . -1 � J�`g'� �s � N ny N3�� '9.Q�y O' N n ��' FRWY �•" u�tiv N� �'�� MEADOW .`^-� C+J AV ��N -Ni ti 9 � � � JONES HAVH AV NE NE ��i �}o� � =�'�ct _.}pWE ' ' E ^ RIp� N �� i oa � z000 �za o �,� �d ,�1�'��N'� >" nv S�NO� '��o,, 3 e°i s` � � 2 � KENNE KA NE gm g � � �--"--'�a � �> y� � urw�e ri �, �w �; r2 x,� ^ � �� LINCOLN��'�AV N LINCOLN � ~g _ �rt�_`t MON REY N A g� NP � ro �i �E NTER�Y � I m �#�'W �� O�a c9� NE �--�� A y . p orQ� �' ` � MONTEREY CT NE L�,� SU,ySF� r^ 1400 NTEREv � N V NE�Qf� m � � m � � � `"�"�1L='-.�� ,N �� xE I "�e�etw Av�N ' ABERDEEN �"F AV � NE � ,� ', y; °� a � �� l�� -—--— �D �� 7 ^� 1200 2000� � ^� � g•Y i ,� alb�t A7 HIZii ��, x ;,� Z � � NF � $... BUINE AV ■ � ^' � 3w�+ ,�T-�uctt ..I iun+ �v � sE y � = 7c N NE ABERDEEN�BU�NE oo v , � � 3 .�a J�s �v �'�,` `r`^^ p J � 2 � � i �� m �y .- r� �'WluS AMAS��AV NE�Dl NE ps� _ � �," ��f� � �r p � �^ � � . � AV N �AV N f ti CuuS +v �n C NE T. _-_--� ' �/ EXHIBIT "B" DOWNSTREAM DRAINAGE MAP �� `� �'� �` 1� `�`��\\\� ,. � � ��\� l, �� ` t ' , � ` ,� ,` � 1 ,..., t;'. ` +'�+,��,1;` 1� \ `-._ �� '` � � � \ � � ,`, ,\ •, ,� ��'/�\�`�� / �� -,� •��;., . ., �`„„ �` \ \ \` " �' ' � \ ` . \ \ • 1►' 1\l� \�� \ 1'` ,'��,�' � 1��i+�\�\�� 1� i ..� � � \ .�`��.w \ \ \ � �. , �\� ��,��\� � � '! P �\��,.\.� ��, �. "'�►M», �`1 \ ,: �°�; '``�` \`� 1 \ � ��\ � ;� � \ � 1`� ��\11`� � 1��Q��4��' �, �\ �`. �.�, � \ � � �-;�,.`.��` � ` � 1 ' � � �\�l` �\1 �`�� ,�� "`*�� .�'�';µ�`�',5�1,��\�\1 \�, / ��ti�. �;�"� �....,.,,,. \ ��. �"�;�:� .,� '� 1 \ \ � � � ��:�� `��,,',�� t, •,: '�'�'��,1��\��\\`� ... ''\� �,. \� � : , � \ ;,l 1 � 1 � \ � �1�. \� � �R ��\1,�`� ��\ >• ��`��5�1,��1��\��. /; �,, '� \ �M 1 \ \ �� ` \ � 1,�� \ �� '. . \. �`' ` �'ti��'\`` �`�` 1`��'�1"�1'��ti1� � � , \ \� ,,M�,,,, \, \� ` ` '�, \ � �' \, � � �� ``� `� \�1i �1� ;`�,!� ��`�\`�� ' 1 � `�-,-, ., \ \ � �` ```� '� \ `�. \ � \ � �� 1� ��`' `�'� � F�� \�\� ��` � ,' `�tr � ��:' ��~� ,\� � � � ��, ' ``, � � � � \ ,�, ` � \\ ,l , , \\1\ � ,. ''�.� `• "' � \ �, � � ti � � � \ \``\ � `` �\ 1��`��.�`\ �� r `,��\�\ \� �,r~`,�.til:• L r��`�' ! � 1;1 �. `�, '` �. �\ � '� � ` � , � � \ ��\ 1\' � �,1 ' � �� `'�\ � `.' ��' �\ ,�"' � l 1 � �`� �' ��.�� \ \ \ \ `� �r i � ::,;. � '�Ly,.��\� �� '� � ,�.:�,:�;�. ,1 I � � t ��`•�,� ~�� \� � �` \ \ � � � \ I `� `�� '�' ' ' � � • y��:`��\�\��`� .,�� ';;-„�:•�� > >� I� < <. ti 1 � l,�... _,.�� , `� \ � ► 1 � 1 �1 � \ \ � � `,� �. , . , , f �r�, ,,�� , ''�\' , ,�� ; ,��;,�\�`�M�`� _~�, ,,,,, , � � � � 1 � , , � �'`�',� ,�t, � a� ,s'1 \� � �� ,.�"'"^ �� \ ;�``�•`�;;;;`^1",';"`\ .;, \'.�\�,\ �� \ � ,� � ` 1, •, � �`\�Z, � ... �'��,0�'`;.�� `�'�` `��, � � \� ` � � �� , .;., ', , , �, � ,. � ,r,,, �, \\,�., `, � ��,,,, .,, � �� . � � �\\'t�1� �, M �\��'�Yt�'�\\�� '�\�\ �� `� � � � � \\ ��< �� ,\, ��;��,;��. � ��,, �� I .�� \�\ �. ._ ,\\ �. � � \ 1 v �ii � �,`�� '��,\�'�ti;�.�.: ,�� I.,,. .`,.,.. � � � \ I �`, �` ` � •1��1 � ,1 � \\`��\\\��\\ ,�� "�." , '�".,� ` , l�l � 61 `�1`�\ \ �1\\ \��`1 � t� 1 � ' �1 ` `�`�`1, 1�, \\``1�` �;\1 \\\�� \,`\�` / \ \ � � � �``'l\\`1 �\� i\��,' ,� \,\��\�,\ �, � �\ ! \ ��, , ��, r ,,�, .`\`��,�, 1r""'_;'��1 ...,, ;,. .; �, � � �` ----ry � \��.��`��;�\\ r ; ' ` `t�� 11 ��\ ` �, .��,,�� ,`�'1� \ �t � ' � P 1.�.:. �. � C' \� � \�� ' ,, � ,, � � � 1 ��'�j�. , � 1 `1 1 .,,�`• '�;,, ` , �`�c� � ' � 1ti��,`� `````„� , ,. . .� n ' 1 � `� , ,� ��'�,�� 1 ��l\ � \ :�; ,. ..1 l,_ �� 1 1 ,,� ��,�� l �� , � _„r.,,,..�.�^ � 1� 1 ``1 ' \1`�, � � �,11�1� �.. C �,, � � � �� , 1�,�� ' i,�� ~ \ �.,, � .. . � �, �1 . . ��,�,��'�� ,, � �, 1�1 ' ,��'', '� �� '-�..�,, �� t ;�. �� 1 � �� , , ... �; � l � �� , �� 1 \ I :r'' •.� .� � ` ♦ ' 1 � { 1, ````��,�1 �' 1 `� \ �•• r � � � �� ,,�\\� �\ I� J,. 1` �� '7 . , � � . �' ♦ 1: � � 1� �\ ,1�� 1 . �` ,,�. �� ti �:� . ,. �, `� 1 ' , i�� '� , � » � � , � � �, � .....�.��..y�. ; 1 ' `��1� 4 �l\�l1 { J ( � � �'►i�1 1 ; ,;yf/ . J 1 � � � + � `�� ( � � 1�\��`��1 � � ,../ ' �, � 1 ,,� .,, i � '•� � � � ` �'�'��1,�1� �1�� \ � ' I , ' „ .; ` , ,��11,1�11`�1 1 ,, � ' .;,,, .. ` . 1 1 1 � ,� � 1 �11�1 1, `� ` � h �� .' /� 1 ��.�" � , . ��,, � i�� \ � � , �� ` � � �\ � .,, � �,. r� � � �1lI ` �`' � � � , '1�g1�1,1 ��,� ��'�1� �� 1 \ ' i ' \ '� 1 • �� 1'11`` ; ` \`�t �r \ � i i , � � \ �� ; � � � ,`, . ., �j�\�,1\\� \ , ��. 1 1't �, �� \ , �,; , ' �, ` � � � 1`. , ` �\ �� ,�� ,� / �ti,. ` •� ��, \ �, ' � 'I t� � , �' �� ,� 1� 1 � , ,�, �, �`, l, � � '1,1 �� \� ` ,�r' ,, ` I � �• � � � \ �� ``�, �, � 1 �� .�. � ►►� � � �� . � � � . 1.•• , � ��;,�� ,��.�, } ' / � �� 1��1� � �\� � `�/ ��. �.�� ?�Z -i.�...�-..`.� ' ; � .�\��\�\ � � ,:,�r ��.\` \�``v .� \ •a....� � 1 .,,�\\�\�� \ � \��. � ``��`�� r,,,� � , , � : . � ��\1�\�,�\•� `��1 � � ''`.--�,. . � '- .. � j ; ��;;;;:�.�;;�� '��; �... .� �----�-•--�- __.. . � i � � ��,��'�: , �-;',�� .,; _._.__._._.�__ ., �r"�.,�;1 1 � 1. � I� '� �.�� :\;�� \� '� , r'�'' \ �� ' � �f ��.��1 I � �� •...,,�. �,� ,�'`' `� j !1) � 1111�(tl( � � �� . ` . L..._.__. ---- -.-._..1-_�}- rrr � � ��.��:� , ._. �1 ,�r � ! . 1rr ,�, ,,. � ' �.� �, � �rr r �..... �i�r �, �' �� , ,, X / � � / II��I! ., \ 11\1�� \ �, , �r� l 't ` ,�'� �j�j�fjT ?� ��\� � I1 I �lil � � � ;r r rit��l, �ti �,'� ► � � � ��i / , r r . ,� \�� t�� \ 1l �Irf �1;11i \ ` �.'i 1�%� � r \ ��1�� 1 1 1 �1� � .___ ;///!il�� ; �/ J � � 1 I 1 !1�� ( � !�/lllllf(!l� .. ,. � .,.�„�' . , � ;� � ,� '� i / , �i� �� ti /! I - � ' '' l�/!/1I1J f�l N I� .,.�.(,.; f r �� ..`_/ r' �l�/ ��1! .��7, r''� "�/li�r1J�(�7 � ', � /��, ,j 1/l 1 r', /��1��,�� ,; - �� ii�r�riN� �' ; � � � �' �.�� v � � � >�� , r .� ? ,,. `� .. • ;� �If►1Jlll��j�' l ,� � � '�1 ` �1 � `"��;.��I�J � ,�� !!f �l�lll�(��Ij�'� I//) . �1�� \�� `.-�, .��,:�i�f /' � / ! �� f�� / �; �p� ��.' �, �,�."'� �1 �.� .r�% /� 1 /� �, ! � 1%'.. ' '�.�. � �`.,,,.,�� ": %•�/� '��.-- / ,,. ;a �" •:• .. �� / � �y�y�, �v// (, ,,•r / � 4— �.. �I � ( —.-----�—._ � 1' �., � I I / r i� ��r�, �� , v i r /,� ! ,r^ ' �'' '�/ � '�%'r ' u ` �'�� r y � � rl� •�.! „/� I � 4�.� :r � , , . /%.,-• , .1 ,'.,;��✓f� � ,� I '.' '''� / ► � � �i , / , • , ',.. , ,; 0'� b � ,.;•..:. ;�� .• / � i,.� � % 3 / /� ►,,i},k �L '�� -, �,.�---- • � � i.�'� . /� �� 'r' �'�'x"�"� r , ...- .�" � y�/ � r �•'� /r� • /�/ � !'�r.,.,,,,..�� 'I��j��'� l "",�,,...r^'�� 1 � // / � � �� /i i ��.�/ �' J� ..r",�,.��^� �� r� // ��1: �'' I� i.� �'`r��/��i'�/'�� \ ...�..�+' �� / ,� / / ;i� �� ,i%''."!�.�t�I S�'/��IVI� \ �~~ � �'�`; � �/ � , .�/ /� �, �, :ri ��, �,r / , �� ..'::`%��'��,��' ri�� ,.� �',�" .r' � .� � /,1� �, '' / �� l� , , ��,� ; � / •��• ,` ,r'/,'•� ��`1r" !I}�� "� �,,f,,,•�;,....�./ �' � � • ,%� / // '� '�'�'� !_ �. � �r�� , ,i "/,�''. ' � ?'.., � ! /'" / , / ! ��''�''��'y1 ``Li'/ �� ''� r / 1 �" � �iT/ � �� ./ / ' .�. I , ,'/fN� 1 � � 1 �r � //"'� � i �� /� ��r�b� 1 / f� �� • �� ` l �� ^,� ,,�• ,:;i;�.;,�?�✓�!�` �,;, . +•r �� , ,,; �,��;r /��,,,'• ',.,�,.�;:%�.�� .,�i N�� '� � /,�� S� � // � �i / �•�/�� • f� l ,,, � �' r � �r � �'�'��yi,-,� f,�,�,• �,,✓ .�, �i�f , � .;,., •, � ` ri ,�7�' s ' ' .�,Y ,'p' /, �```r �•.'�''�� ' ' / � �' -�` -•. :��- .., ''. , . - -�=�� , .�, �� -�.. , �i��7��'/j�� i"'� // /II.'��,I �� \ / ,�.•"�' •i'� '��• �^�� f 'tr� r��/ ril) ~� � r� � �~..{ �� 'I ,�. r �y�. �/ ,r�,, ,,:�� ,. .,�• �'/,. .�' �, 1 '/t� �ir //fj;- • . r /:. 'i.�. � ."�� (- / .�r'� �/� ,/ / 1 ��/% � �•'t �� / � / / � �, �/�''� r!, ,�r� � ,ri., • ' �� J/ �� \ .r"� I ' ''�� y' �//'� ,�"'` �/^ .. '� /'"....,,.i`� ' � � ,/ �. ►",�lt�//ri r c�/. ',<f�.�;��,,j� ,.y"!'�.� �..i'/.d��a�� _ . ��~• ��• ��•� �///�/%/ � .,� t.'r �. '4�''r., , _ EXHIBIT "C" OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE OFF-SITE ANALYSIS DRAINAG� SYSTEM TABLE Surface Water Design Manual, Core Requirement #2 Basin: Lake Washineton Subbasin Name: Subbasin Number: Symbol Drainage Component Drainage Camponent Slope Distance �xisting Potential Observations oP Field Type,Name,.and Size Uescription firom Site ProUlems Problems Inspector C�ischarge Resource;Reviewer,or Resident See Map Type:sheet tlow,swale,stream, Drainage basin,vegetadon,cover, '% Ft Cousuicuu¢5,under capaciry,ponding, Tributary arca,likclil�ood of problem, channel,pipe,pond:size,diameter, depth,type of sensitive area,volume overtopping,flooding,habitat or overtlow pathways,potendal impacts surface area organism deswcdon,scouring,bank sloughing,sedimentataoo,incision, other erosion 1 Sheetflow From site down N.E. 6th 18 0 to 110 None noted None noted Street 2 Catch basin to catch basin 12-inch RCP 0.5 110 to 125 None noted None noted 3 12-inch RCP Catch basin to catch basin 5 125 to 225 None noted None noted 4 12-inch RCP Catch basin to catch basin 5 225 to 270 None noted None noted 5 12-inch RCP Catch basin to catch basin 5 270 ro 420 None noted None noted 6 12-inch RCP Catch basin to catch basin 5 420 to 480 None noted None noted 7 12-inch RCP Catch basin to catch basin 5 480 to 630 None noted None noted 8 12-inch RCP Under Sunset Boulevard - 630 to 685 I�Ione noted None noted 9 Ditch through thick 2-foot bottom,4 feet deep, 1:l 15 685 tc�935 None noted None noted vegetation side slopes 10 30-inch CMP Under 40S - 93S tc� 1,285 None noted None noted 1 1 Swale with wetland 16-foot bottom, 3 feet deep 0.5 1,285 tc> 2,285 None noted None nc�ted plantings 10125.003 [JYJ/ach) � Aa � �E-� � � � � � � W LEGEND SPECIAL FLOOD HAZARD AREAS INUNDHTED BY 100-YEAR FLOOD ZONE A W base Ik�d elevni�ra dmm�:xd. NATIONAL FLOOD INSUAANCE PR06RAM Z°"E� °�"°°d�� Z� � ��,b � �, �.,.� � �,�: � � � ��. ZONE AO Fbod deple d t w 7 ke� I�ully sheet F'� n�.. � �:g �nr. m*+� � e��:,Re.va„�a,��n„oa.�. vebriuc, also deenmLxa. FLOOD INSURANGE RATE MAP Z�E A99 To � � �, ,�. � �, F� � �� :��. HING COUNTY Z°"E" `°�,' "°°d .*" ,�'. '� «�„ , �«�:��,,:,�. WASHINGTON AND Z�,� ��,,, „�, w;� „�,,, ,,�,,, �„� INCORPOR.ATED AR,EAS �°"� � "°°" �°°^� "�^°°� il FLOODWAY ARFAS IN ZONE AE �, OTHER FLOOD AREAS I PANEL 371 OF 1725 �=�°� =oNE x ��d 5��;��,�-,t�, �� c:c .,tF' ip�Ci -:��e ��::I:r..'. .ar:T fl•n,'i-�: 7 hot�a dainagc d ka dun . { i( 1 sqw�e mlr: and areas prd xd by . !I �'� I ( Irms trom t0o-yex fbod Vi �i ii i i �} OTHER �1REAS 1=i II I JrJ"1ih1� I I ZONE X Mea dnmrined b be wside 506-yrar �I r:�r ur.iTr ,� � F:.t: . ��r. [ J i� � — — - n°°°�'". 4' ZONE D Nea which lood harxd are � �r�e courtrv. �wNr.onPonnlEo onE�s s3oon osn F "'d`a'"°"`d. � �urraa an oF s3ooee os�n F ! UhtOEVELOPED COASTAL BARRIERS � � � \ � I i �ii � ��+Kd iee1�neea oux,w�e I1983 1990 Piotecicd h�as ��,' il Coeslal Wnier arees are nortnally bcated within or a4xern m Special ��{ � Flood Hazmd Neas. �� Fiood Boundary � � G MAP NUMBER �'°°°'"°�B°�"°°� ; j 53033C0971 F - _ z°�° B°,� � i e«,�werr a�w so•aai Fwoa �,��,�, MAP REYISED: � Z� a � 4`� MAY 16,1995 w� �„F�,°�',_ Zones. � Bass Flood Ebvalion LMe: a° 0 5f3 oeveou+ m Fesc sce l.,.p aae. �� lor Eleveuon Osturn. � �D�—�D) c.oss sxuon�.ie I � Base F1ood EhvaCon in Feet '�i I'ederal Emergency Management Agency iE�qH�1 �m�, u�o,,,, w�u�� ,. II RM7 See Map bidav Mr Ekrouon Dxum X Ebvetion Re/mence Merk • A4� Ri�er A�ls Fia¢onW Coord�etes Besed on NwM 97°07'30".72°2230" �vnarican Datum oF t927 iknD �n �G{'�A�� - � � FEMA MAP �,�� IVORTH � • � _ = NORTH • PELLY AVENUE � x N � Z � � � PARK AVENUE NORTH �AKE WASHINGTON BOULEVARD NORTH � r/� N N � � m � � � � m � GARDEN AVENUE NORTH � o � � ��N��d m m MEADOW r,, AVENUE ~ NORTH � � � � NL��N � � � z �' � FACTORY � AVENUE NORTH z � 0 � � � cn o ,�� p � ��AT rt+ O � � ��' O N � o m � a� � � cn -+ O z ��a � y 4 S��SFT Z °z � eoU�F�ARD HOUSER wAY �02 NORry NORTH �y ti� 3 0 � �' S�NSET 7 � e B��LEVqRD 9O�S0 'Y WAY NF tiC � � m � � �' 'L 0981 � EXHIBIT "E" SENSITIVE AREAS MAP FOLIOS f��;. . ,r �,�. 1 �v H., . i .,,.K,� _. , i J1 '. � Y C / , � r � �ji r ,� �. ,� r.; {p� J �,�y , .i.� h''y ,��A r_J-- � _ . ... 1 I �I Y' � : j�;?"` �j,�� "t�� `rn, • , .� ._ -.-4,_ . .�_� � � I � L �� u � - ?�"•�y � l J � _� �`;3i�' � „�'�� !�`fx�.�d'� � '(' r✓� , +i''/ . _ _ ` M , ,,,,. � 3{� ;� .. , ,� '� .� ,,,�n/ � ' H y°f,yb�'�' � � ,�4 1 � �-T.��/^yI '•.. � . .,.._. � ..��r ,''.1fi .{(...' '' I '�� "� ��_..L._y`- .,. �� i.�Yf �'r.� r--�)�.1,�,.. \ .�� T I `�� r..:.. . � � ,�. Ij,f/ , .. �; ..J -I , � 1. f� � '��. ..� NK�'ti� �"�V1�L�,'u�.^s�l A�.. �I.r I � ..D� - ;�.. ..'� �'I ,,,i L ` � ' �� r . ,. � 'h. ' . � � •wi�� , `,�:. '_ �.,(� �� , �ry � �`°. �1„ r � ;i,,,,.r,.'"`.�' �� M3' 1, N F-""k' _ � 0 . ! " �'I .��"''��s�=�' ��i. ,� �� a""l - Z , , � .�, .., �; y� �.�a� ;�: -k. :. -- ' - - .. 1,�,,�� ,,,� � ,�� .;.. � .. ` ,.,, ��t ` � � .. .Y . .. 1.I � .y '\ .��' � �. .8 ' y �\F� ,.i' � .. '"�y" _�r� � I', , } �� _ � � �� / sr ��'n��.ij.� � � y,AI1W� �' �4, '•�-jj y t °'`Yw'i��,�� O f 3� � l� r .y�.y'�"� '� '� �..�••" 1 .`�; �.�-�-- f �, \� � � 4 � �'� f. �+ _ �� r-f� � E-..a� : `4ti ,�„ �v.s. � R' ^ L • �` 1 1\ -�'+�`� �"''. � a:,-, y . — , r'��. }�� . . ;�� ''��H"4 �"I"'1 �: k'h � �l�`f � . ��d�.l�, ' .� N _ . • � I I , ��, � +{}� �( M �,�:. ...�� ':.l._�"T'�,- � �;_: ., ,�"`t 11LL � r � - - r' 1 - �a✓ . �y.� ;:�� 9w � , . ,,�� Q�y e .. ,��' '� _�4 �r� �_nY'.� I.Y , �'� , 1 f ��».. "� +,�: ��:-j r „u+ , r �..`�+ ;'Ij�`b �, , ,. • [,�S] ��i� 51 I r 6 r„ pr frx�, ? . . � }//.� Nr /� . L �,,. f1� Y '� . .\ f. 1 I �. � 1. ,l �� h � . - 11AI /�.��`ur .. -�Q � �// �w`4 l�l S , ' :;��1 l� il �J •L �{1't 'y�' �j � /��I. ' ` , 1�'�•^��. ♦YC � � .. .. � . ..�f.7,� �+ � ,. .. . .. , f'1 �l �- � , ��.: �: �:� ,,.. ,, s.� , i� , f� t e m IwIY' <<'�'>:-'1 i \ .�'�� 1 1�� ( '1 ►�.. � t;:• \ f� r �:� � � . . a' � • ; � I�• ��'1 � ..�' �.V.�� i .,4l��. .. � { -� } , `:'1 .. , � � i; 1.�� .+i.fi�� ,�� ',�.,, 'y � . ,.\.¢ 1'�.�a, ,,.`-� J �,.)'. W �a .�rt5 � !�� i' j :.�,„�,�� r+�"�,3 a. i � �' � �, _ ?'rK f+ � � ': � � r �3 \`� y � �� ; � � � � ' ��*y. t w"::l /� . .a j�,.;�a, �f �: �I"Y.� ^ ! ,,. a *"",� �/ Q }' * i , 1\` �'. a � ' � .��, t� �'wM �� „J ,+.,::)' S ,.', "�� y� �7-��i.�:�. �.� ar„�"' ,�� '.., (/� � 0 -y ) � \� �f . �y �L✓ , �1'�` I il 'r �ar"I i� �>'�'�� ,^Wl.• .�-+1 �\. � �,��;., � . �,� ;i �i• I� ' r �rl�� + + E,,;, �. I t /, .. . � � � �"`�. . /' : , , �,r-�; �� C� 4� OC - �,. � , ` , . , .}...n�y�� M...a.�i.• . ..�.y. �!I I� � ( � ,�,,, 1 �`��..�'l. . .,��:t:�:�w�,wx�. �� . t il . !� r��' . � �� _ r �',u.,. 1C !�I Q �Sv a,. I �t.�Yy ,.N �.+ ^'�l� JY�a r ! I i�� H . rI.1��I 1��+ ` . � � < / `�� N �:i:�� -N- �1� 1 '. iy�,�,a/ �Si�� .. ••' ��;i� �t',� ��M1 ��t � .i � �'1.3.:�� i�.'� , •.i � .� f .}�.1 i�� ..::�E� �( �y �, 1 1�'1 ` � , � w� c U , , h,�� _�.�.. �.. . .F '��.."' :')i i t. .,%.,� e�, � ` � i q}}}1 tj.,� J. � I i � , t a �{ � ""✓ . '��ai f'� I �+�k/ �.�k�. �� .M�. �WI ..Ji,�., d� �iy�,;� �.�{�,., �A �/,� � Y� � j in�l T" �� ,.. f r�`� {„'•' "' • .l� �� -4, � Z r � � �� , `1,' �^'•� �� ' � '�`�, � �, _` �' '✓�� t ,,y. �� I/1 _� � .I, *r i'1 : r � ��,� / ��1 �+r r . 1'�' �L�/ ,� �i l - tr � � � y l�tw.: "�^- � � ,� i �,l f S ' O � � r�'�`!'.c 4 �,:� �"��'��., �'�ry�'J a i r�h.` .f�'��1 '� ` v J ,:1�' ` �7 ., � !.�rv v„' ��,J3 l �.�y{nf ' � ,F y .N � f � i �}��S�y,}�:�"i.�+ ° � +�� -i, 9� 1 f� ��y � ` � �`• � ��V'f O � � C . �*'Y�.� �l��. .I� k .. •�,.: . ' ' i' I . ' .', \ yY � J �„ �,�.�.. .�t ''� +� d ..J..�+.+w. t 1� F � l --`l � �� LL v, - {� , � � >.; p r - ~,• w r `+�", b � '•y'J�';�1"�� , � � .� ��-�:, ° �l' � � � w � �"i � '� y �' �,, ,I"„-r; f�"t�\,� '� ,.k..�� '� /! .,' � Q y � r-S '"' ,w .' Y• •'^-w �� } ��1 �� . 1' )x m '�,' // .vi. �1J �' , t��i. t ♦C I � f � �� i �./ � :. j� �'�a�� . I I �� .L�•`. "" � ;�I!�—�^l�,l� f 4' 'J}✓-: ' / {�. . . �/: I � � H { r'� i,"' r' �' � � �° � r;.. / Y�1 �` `'r' ' �L G� C�� cn �. �� ,,!'�� ,. ; ,�/�•4�`�-' - �.` � '`� r ; � �• �l_._�..,.._~?� w t' � k!fF �"}' I �� - � 1 '� �i "y""f ��'' ' a ./`� % d': CR�,F � .:+ � � +' � �� ,�I� • , ` :� ) �" ��' .. �..� ---� . � � �ti+.'`f��. -�A � . �f1� � y NN,�]_.. .�. L..`__ .� �y. '. "� �";, . � .x� .� } � � rR 'i� _.I•t�. � �� '-a" � .. t��,- U 'i , � �: �{y 1 Z �� ' '�� I !"'�..Y`�z�-�l _ .,..�..-r: �-- 'I'!. �., �t' � �� ^l. v rt L� ./ r'Y� �. ��,ti+wi .1.�'.� y t _ . .t'1�..�.�.. �° .� �"C i��,�` ��' Y ' . p ��1 � ;�T 'u'�y,.k, �. ' � �} � t t,.. � .: o � '1. A �,c c a_Q ri� ' � �y�,,,� � .., »F� � , , F� . �� {.- -� I• ' ..,/ — � � �:�e �Emv""Ac ` � ¢��r � �t It} �� i.'.yY","r'�`'y� \ - ''_ _ -_ / .t� �,F ��=A.=O„�« ~� ,'� � � \ ' .. �/ �r �' ..«.� _•�. � �r•� �� v G..�O 9��'C � w � ';�-- i:T.y �„ �� ,�,:;i,��..1„�N�?"a��. }.,,- ' 1"'` .-+� '` � r( ..�:Yr'n �A ro.�v;�,L„�.v � � U :y. �/�) . . .�, yw.��.� i :�' i ' �1 � .y� _ L C 0 V � �� ,,. 'l.t \ � 4M.�( .. . �., ,r.,-;'_ 1 'I+' I L Y.� I: i C�y v�i L N�Y � Al�1�irl, � , �� h f\\�.I�" �''�l. �' M �'a �� r��'� „� � '�,, '�` ,�' ', '.� � �1� h'0�a3'oN« U7 f ia++n'^r"'�'r ,.�...h� .I Y� �� , � .. . I - F - , =L �. _ � � . ^ I � '��i 1 T • y 1 � n q�w N� C i _ ��.ii J _ .�_ � :' . ... , .. -'.. -,�... S��. "� �j Z" Y � `.��_.� � -� K�`�� `I E a+�N..p". :.r..._�._.�_..._.��...,,..J._.� y 1 . @.;--'- �,�� •r•. "�� ., -r I - A c �,r' ,..., ""'�L r� �, n't .r�::;+ y� :. •rr� � O >q_L�O� �� ' �� 4 - ,.. �4 � _�- . � r �� , �� •' m � � � � � �� L � ' - �w -�w ,. , � T - - t �� . , ' (-.-... ^1� �....,. ' .�- �� .�'_ L_'�„�, �-,'� ,«,...,.1--Y-� � _ �-. .,- i � �E� _ _ _ `' z 3..mc i �"'c o Hu. ._ ,E::�c�.....1:_..........,.u, ..f"'(.. .]�I�� , ��---r� 1�. .r �L. , � --iT i . . � , i rv�n�. . . f�i 1 , ,.. _L v.,n�..c w �.,�a�ws�• �m ��M n ��rsy3 `� ►i,�'ai !s �`v�s�� aa f � �� H�� i 1 f. �if �� ...�....� '°� s � � �� ■ o�. � �` ,��.� � � �� _ �� ;�� _��+'� � �. , . , ��.�� w=�� • ti � '' `� �� :��v� �� '�� .- _ �� .. �.�� -��.. ��; .�� — �� !�w " �9�c . �y. :� �. �� ,�, ti I� ' � �� `� � �� I � � � � �,= E a � � *�. '� � ��, '9� Ij��` .� y.t� ��- �� .�-.C� __ `� ; f�I�ti� ,�� . �T ��,in��s - _ _ � ��iit� �� l�� - � ;� �� •�'� ��'•� _ � '� - �� `� �, � aiCs► i��r�v�i ;a _ �� .,� :�? •�_ � �1�� s ��i t%�•. r� ' � � '\ �, - �� ►� �� =�� i= � -� _ ' �� .�:. �` � ��.5 � `� «. �� ..�_:_� ��:� �� •� � ; � tt�� ' .,� �� -f �� .�, . `�, �o� �s� #. �• �r��,�� . . ,�� ' ��.�.. - e : ,�_ � � `��,.. ��;�. �� , � .�r �� '�:��.�.- � , ��.��! =� .�i�ar�� - ��. � �a� ! ��s ��'f`•�€��`� � �'� � �t� �� `�s�� \� �� y:_ . . €��'�i'7,�� _��: �� ;��.��_e . �':� ��`t � ::�9a ��-_�:�� ' � �'� �� .��` � �� .. � � � � . ; ,�� ,�„� �� 1 �� p ��`■-: .!�_ �� a� �t 4 � � 1 ��•/ � 'Mi ��,_��. .. _;� �� {.. �t��'Y . �� _��[s '_. �� y ss�� . i . ��'�, �, i ��"' ; �� '�� '�� ' .. - � �� .a�� '�;'�. �'��;'` �� . .� �,� .s � � �_ , ii � �� '��i � � �,��'��i�� l�=�� g�� .�� :�' s,,,�i � � - � � _ ��„��1 � ;i�;� ��i�� - �` �` �"�.:• � l �1�r, � .. l!4��E�i1� ' �� •-� . - � t!`�#� .. `��.�.�_ ��. �� i1MRSi;i:�. � ��. _- �� E��. �� g��!ii�: j� R .7/� �i�I( ��"'- �{. � � �� .� ��• �� „-��.`5, � .� 1 1: � ' -..:� ..� ` , •� ��j �.��'■��'��" �` /�� 3i::?,_� ��i III �' I,�� F.it ; � �.��°�],!�� '1 � �:.` `:; ` i r � � � �. �� '� �� F.f.��- - � I � - .1' ��.:1l�i �t'�i �� - �s�ai!� �� i��° �<�� ,�. `-�?�: l��,l�� R��"t�'�'� ��ti� -� ��,°�' ��-�� --��"��' �:�, �:��:. �:� - a.'�.�«�� -: �` � �� 1• � �.� � � - �� '� `{�g. t. �_-.� � ��i��.� J.'�.. '�� ' ,. /y� �' `ast'! ��(� q� •��i1. . .r3: � ! � 1.Tt��es * i :�.:�'�1�� 1 . + �.� p � � :�� i �� .� l �°' �� = S �- _��T�'��L± ��c��a � 3."Si� i�j� 51�� `� .��-■�� R° . �� !�".. s ��1 � � � �� ,� ��p�� ' � � �� Y� �� - „� ,��; - �Y � s�� -� �� i��s � �'� � '��1�� ,��, € + '�i.�i_�1i '�� : e � 1 ��w �- � � �� f:�� _ � y i�� ,� ��:� �� '� �� _ -�..� , � �� '"'�-�; � ��► __ -•e� 1 - � . � • � �• . . . _ � . � �� . . . - � . - . — '� . - . •, . . . :..��::: '�,� t � ',� a' - s a��aa�a ��:a� �j ` '�,. ��ii�r . � '�� '.�� ,��v��' il -�-� ��}� 'i�a�.�.:, � � t�!`/'��'�� '�y � r� �`� .�� ..-�� ''"R �! � , _ �� _ �.e++'"� /q 4-� �x� {�� /' 'r � 'r � �� i �� '� �. =��q `:�, �� ; ��fi�` � .E �� i t � � _ � � .�11�� , ��— :�=_. '�'� � ;,. � ' �� t Ili�i� p�.. _ s:_ � �� — ; r _ ,.. �� .� � !lili� ►- ��- - � .�� r .� �..; IUI�! �� - _ � �.,., ►�Ilf�� #�� - �`� � t�1 NII� � �� _ - � 1 , , .w�� ,. i �� • : .� �o� �� :�. ! 1�� .# � �'��.-' �� : �- � - i�il ��` � � 5:- _ y�� i � i �. -� y - � �� i��,� �� 6 �� y� . .L�.�.� ��•i :� �1 a ��stti�l� �� 1l� . . ��i� � ��P� � � �� :, , ��#�� , � _ ` ` � �� ' �.�Il�i �� -�m°' �� , 'a� � �� - � ��. - � ''� .� �'� . ��':'�a� - �i��._��— �; �� :'--�� 2 ., � ■ �-;. :. � : �-; ��. 1_ -z . � ��l � � '� � � ! �', �,� �� _� � ��4� � , ��$�� _ ' � �� _ � ��: : p_ , , �� . `y,��.�,,� « �.�� - � �, , �,_ �.� �,. „r� i� .� �� ,�€ ai ��, I� � �' ��'� a° /��1�Ilii�yr•: .I � s4� �"a'i' : �, �l ";,, .�,a .sA' �� ,., �- ��1;`� � ` �� i��/�'�. ��IIz �� , ��l� �� `-.„. .; . ,�i-�,� w��=� � ��w w: �-.�.. _ �� .,g � - . � �! '�'.�.'�71�'r,�,.�[i�� t��4�+ � ��r �� ,lt�s�- '�, --- +�� l�E:� ��9[ ; � ��f��i�. :'��t�''�'--��1L��: �41at�� '�`�;��1��:i��;�� ; � � �.� � �-��=_ `� �3�a'�� i� ,�. � �' �.�� -��r,'+ �:_ �� ;� -- � -'��- ,�� . �� , . , �/" ��F�'�"�� ;� � . - ��°dr�� 1 '� _` - � � . ��i �� . � ; � . il��l.RlRtt�� _ ��'�'d��, � �� ,�. � � � �'..��.:n,� � �1',��_�� •� �' � ' �;.�, ' ,� �, ��,•�� .�� ; � � ��' � � ..3. �-- - q.- l��a. �#.�� l +�asa�� 3.��.��'— �� ,i'�� T � � � > ��y 1�,� � � ��`0:�� 9'�� `.��,,�,�� S.. `�i,2�� _ � ��.M��h.�3i'�� Q��1�'#�l�/��_�� ,�Y�'� � �_ .� . ,�, , �. �?♦ � , �s.�� '��'�. ��i�il� '' ,� ;` ' �f�.��F. �E��- �'�� 3 � �� ' ' ';' '1��•� � �'��;� �` ��r��, t�� +�! ��rr- �� ; �� ., � . � ��. �'��'i ' ' _ �: ' � ._ �,�„ �t�E`�< ��i.�.,. .�. .��i! '� � ` i�_�� t ��"��'� ��ax � '� ��.�'x�* '� ' '4'� � g EIJ.�'�j �T�►� :�- i � � ��r '''�`�.��" ¢ � ;'•�i i F� #��F�`� _ � � ��„` �� ` y �r � � � .�. �� • !� � �.� � .. - . 1 � ' . • 1 • . . � „` .' � , � � � � � � � � �� .� • � . .., . . ,� ! '� � �',�- ' � ;, 1' ' �;-�+�� _ � }° ��._.._..!:,�� ` t-' _��a�) ��( - ,�y��, �Z '-� .i' -:e>f'-.' �� ,'�.�� r .� , `_,_ �J �. � ,�-1':tt` c • �c-�-'t.�— '` '-�,:� E.t' ,� �,,:� - _ - � r-�- s. �.�. - ♦'. `�`T�7'i a _"E .y,� ,:�� F. � 1-t• /; _ ��.. ! � 4� � .. .� 3 � i �;� ; t, . ,� �.. . '` � 1 �f�� !r. ' :1.�: �� -. . .. G� �� t fr •� �• ', � 1 `��. +�y �I l �a � \ �: 3 �� _� �� _ {~ � _ t � K �f �. . � . f �� .` � r ..1� ��:-�� _c'7t'. '{�.`` . 1 F- i � �'. \� �'L� �:��• �; ��-. .t:� � �y-1 j' _� .. __ t �9° . . .i. t '_�� i. . 'r_ �.y . - � �, � .:s, . �� .�T� •., _,� . _ `�;� � �:� - - _ j'�'� .Y � ). r .-�. �-�1- 'f� . _ - � j`� �� f, �� ' F' � '��l . \ � F - r K� �, i .'�p!�, `i 1 - � . �C. ( -r� ��. - �- �r- - � � -_ -�t �� e _ +` Y�� _�,. i _i{� - j `'1 !.�, . ... _ �*. _ � _ r . , , ��r '�g. , , �� -�r� -: � ,_ �.� ;.' ,,;,� ��'�--;` ,ti ? � `, ` � 3 ,�r..� �� " ' -� �, ` •; y t � `I � k�� ... �� .�. � �� -... � �'.. _' �� ` �.i -�j[ �; 't ��. _` a.� �i;" \ l�� \�- f'� �-��c} t .}- L! -'T: • � y 1' '/ .� : I I t m� #'� I • / �� /' � �� ', � . . -- +�n�.: � � L .�� ' �+�� .T� �.C� � - 1 � � 1 ''�,-�^�� ♦ � �-�, . �i. �-__� i /�' . _ i.�tt' '� � r ti .'{ .q r"-?�.- � ,r- � .. . �', 1 •-Z-� � T '� � �- i \ � a �� `•� __i � J � :- � � l., r � . .j� rl �, I• . i �C.�ti: � ,- , t` . j � t- �. E 'I ' '�� t �:- :� -} . J_T ` `" . �`' , t � � .� ' i , ;:�. �� i ��"�r-� � +`_� � �r*-�, � '� ----� "-'� � .�• _ `�.. �` i`,.{ �'�� i � , `}- � �� . �}1�.-,� � �. 4 �� ' �V ` �f�� :�i�� "}��`� .�_`. ';5+, i �� F � g � F _ r:_. � '� � ` `� # f _ I, . 1 , , ;, �. ., t� �i.,.� � f� .r�,� S_, ` .._.. _� --� -t �-t' �� - �#:'. - , `.�y+� : _ ;�� r - � .:i.�-�..a`�� ..�t �. �_ � � - +F i -e-1 '. yes�. i � .-, �� • ..� ,;'y...� - - f._ �`, •;� ,1� . �.�� ,� i� .� � {.�_,., ;� ,. �. � s .-qry F+� L }`� F fi . �` a� T � ��`�.� �. �%`I .� Y .��`.,��l�- t� ��.��C - ,. * f��...�: ��y\ #i` � ! � �� J t� � �� -' �-' �� - � �� .I { r '�� ~ � '�. I +� j' � iH �-� 1 ' � � � -� ��y____� "� �t �=T'_' ' ` a ;� `-1�-' � ' � - �-'_?!3 a � � -� ,-•� .- \'� '�f I . 1 1 �, ;�,: ' � -. �,>-�: �'� , � r 7 _ �� ' r � , -�___-i�1_" � �`� � f' �'{ r �� ; l'; - i - r � �';� .� _ _._ . _ : _ .' {�j -:� . � � .� Y.. �K � ! , _ {`� � _-( � __ � ' } _ : � i . i.! F� 'w._ ..� � t- ' -I�._ x_ r F f4 �. ._.J . � . r� _ / ")"' - ��~ — �_� _ i_ , . f�,. 3 a `�' :� ._��_,� t l<�, � ` �- 'r -'� � � �� •- � �� ; ��'� -"E� � _ - i � . �:j x ``F, � � _ j - �, , � _ � _.. ; ' r += �+, � t ,�`+� l,�. r ''�. � t � ".y.� � � m i--r, c..l. -.'�/ .: ;�t'... . � . � ... "::-r�. - - =� - �� t n � � b"C �� . - ' .� , _ �' \ 1 � 3 S�- _-� ! ��' �h - � � \ �.1� n� �? � _ :i ��_ � �� `�� -S� ,'�,, �` _ �J�- _- y� N �l. � {I !` �. '��- _�'. _�. '' 1! �3 - �,�. �� d �r � �;�� -- � � � : r , o �, _ - . --, - _ t I� .�:. (z - � y � �� 3J/ -'� � 1 T . .. � '� �� n� � � � �no , n- . � '�,� f� , '�� Y T�� :•� i i� �r .i t ; " L, l, $,�� - - J ,� - � 1 \ . � �_ ; , i _ � �'X/. � t .. .+�....{ � w a,� � � : y 'IC. ��iC � y.l�� (�i ! � . . . �: }_ . �r�4, . i . � boundaries of the sensitive areas dis- $ee wetlands and landslide hazard maps tor Seismic Hazard ed on these enaps are approximate. adtlitionat potential seismic hazard areas. itionat sensitive areas that have not Wetlands and landslide areas are susceptiDle � mapped maY be present on a deve!- to failure during earthquakes. Other seismic �^� _ ent proposal site. W�ere differences hazard areas not shown on this maD are G r between what is itlustrated on these shorelirtes underlain Dy lacustrine sediments; s and the site conditions,the actual pre- these are susceptible to liquetaction. e or absence on the site of the sensitive - as defined in tlYe Sensitive Area nance-is the legal control. 1 1!2 0 1 MILE ��HA�� S � SEISMIC HAZARD AREAS ,,�� NORTH SOURCE: 1990 KING COUPJTY SENSITIVE AFEAS FOUO ,. , . � T . ... . � L , � � . , � �,.rt�^ , r � . �r } , ..�.� , , �� . . N7 °a,�e a �'"Gil � �, Y.. 7 --- F �, �� `� ��' jJr , � ��..� r ._i._.. � _ � .� � , i / � � f ��, � .., 1 �,"j � , ; .. 1�+ F y yr � f"4+:�' ,i i , � ' C. �r' � . ._.jk �., ...r t �� IE'�� ;r• �/r � ;�� Y��if (j ��I f r�a C . � �' f �, , � _�, ;/ ,_, �II � �/,�,�` � .,v J�iY'( � �/'. ' l . I � �,.ill I �.I�:.._._ �.� t� /,.,W. ' �.�%� Y I .Y 1f .^ .. � �. i1 T.�'(." ' I -r ' \1 ; ( ...� J � ,� . ' � r . � ,, .' b, ,,�^i..,! � . , �� 1� f �} .�.:.��` K_`' "i��M t ��1�..f } �� T. ' � � .....t_ ��hl d .I � ��.4': � • ( i ,lL�� ;' ,.. � I i , '� �,,. �rc'r r�a �� • � � �.. ,-,�. � � �. "x O �. r.... , 1 a i �,� f.i`� t I -�-f N ' ' ��• � •� ` :""� '/i I'.` -7� y'�rn ,� , , � , -l�l � � „ � ' �i ;`� '�;r ' � »F�r, �. �,l 1� 1_ 1 f _.1 St� ., 2 �/.:I� r�� ._'�� -Tr-r �z ��.��I a- ��1.,'• _.J h �`9 ,..f-,,fr7 ;k � t "t� � � /� !"r '�� "�. f�� ".��''* � _ _ ..__.._..� ^ 1 . I � , � 1 r�...... � � '..� ,,. . �.I,. 1 . �'.. � f �,, *I x.� V,� ��.! (,�,� �� --_ �� `_�r- �..' . � C, � �.�� :. ...._J..' � /r � 'I' r �' d., + � "L �kC� ��+�� ,:�j�.� '..__.I � �1 � �,.1 '� � I'� � / c � � � I ..� �� :-- "` ''"'�,f �� r • 1� ` � y �.....,..�--��. T)�� ,�, ^ � � i � :'�aa'"' ;,,� ws•��{.�,'��*+.�c.ss � �I'` I ':J-._ r.i}` -k. � t" 3 17 _ ` ,w.-. .h,�,�yi.., .....w. 0. � v�. .�...,, ��'+ t j �.r 1-,y "j C ,y,: . �' C r ,F.--�� r � _� � V r d `� '�"' �'"J ,.�, .b . � -�:. .. � .i � ` . ; �r ,, d. ., "" .. � -� f�r-^r- _ ��.. p .. �. _ �......,_ ..,, 1 a"� � � Y ".�� - fA � ;�r r::�� ,_ � . �J m, �. .� ; � � .. I r r �� , _.. + i� � .�- .��` p ~ - . 3 I � I..r.IJI� ��/ ;7.: r � a ��-/'��"it 1 l' p . N ` ?� � � �, t '��, � { f �. (—�. � �, .: = ` �� 1 � `� 1�[ � 1 4 , r �� v t�: w� � �-�. � i � �! _� ` r°` � f,,�,� r . (��Er � ., . , , �1 � � - i _,. i � �,,--"`"rr f �_`,�:,.� :,,.. � ,,_ .� "�.�t�rt: ;: �.� ,. ;,,�� 1 - i,y: �r , �,,,..._,,.,,,,,,� � ., � �, _ � ,�� , �- ,�� _ �...- _. � �._��`,` ;'F; . , �.. .,,r,. ,...-• r ,fA � �a a 1 �' �t�T,-T."_T— '�-- � , � I II ' "'l�a" z� � �d: �Zf � ' r � � I _ � , � � � � �, � , � ,� � .. 1_ � � `;T��,�� ' '+ �'T,� r+,T;��:` I i': I r r �;� J w�^'r "" y _� � '��'„ � ,. • j � ._. _T �.:. "`,r �..,�; � r�-;1-; _� , . ,. � ,,,,,,,_. -�' . 1ldy �� _f�t,.� ' �`.�,i ��.,a,�. {� �yL.l I .�:� rt��';^,�.. , ,�� v: �..1 } ^� /� �6 � I ( �y ",�;r_' � r � �1 'f�' , / ,-t} � � sl�i1 J'�- �V'r �r i� niT-� r V J � � / �` i,` f , . . .� r��'�� .�,�i:� , ��.1�. �'��f: � ,,.;, .�� /• , �� '° , � � �.� . � � I 1, . ��G) '�� rp'; ' yi��;.N"`� 1.e<'2; .I � �� ..\ ,....,- W� .�, �:::wy��'��.ttAs�._n �,..�u'V. � � �• }�/' ��+'� '"a�' I/ 7 � , , /� `�I�r�-� ,��.--�""�„`��"r(; '� � Q 1 ��., �' ..Y'1 � .�_l� j �� .../` , Pr.n) � � .- �a � r� .� f �� -,� �� r�, � ,��f��,N ��l 3:� �I:' I t:' � ) ��.._.� , !?',� j ,�v�,�� ._.-�___ C� w �"'� � �kr f,, " �y ��]� r � � I I i: ;+'- "F 17 �`�' %''� 7�' . ��j.' t r,s'J'�}NT�T'�j'jHvt,4 �d� ��'r 'ra .,� agf . ,✓ ��y . .. � M► . .. � I � ;*,O�.C�1��k@��t��X�9�Suu.w��,'�it1�:` i �'��•J� j y�!Y �� '_f /..�• `-,�✓Y�i .r � �.�'�1��r'., I � "''� ,.f 1..iT:.1.1�� - ...I �^ Y�� _ �r'�,� f��nFr,i � Yi ,p'" 41'� ,I t:r . M� ' � '�-. /•�� ' _° l. �' �." � � �� I��.��1.. i� �_._... ��.�.,.�.ar,. ��' i �c4Jlt'1� r �� 4 f�. ��i e/. .�J ! . a �" -��'.7" �,..�,�. ITy..�...n,,,��,r,- ..l 1i�,+ �"'^A �+�.: 1;.6 i ;I'.. 1.i � � .. i .� � f� 4 � �� .. � �!`y�r� �"�,,��„_�'1"M br �� i.�ti tly`�.a, .. � � { '��G-�, ,�•�. �`/ °f ;r�'�e'�+�''�� \ ..,�('Ly,. .x.�'+ yi �.��'�i�I f�'"j i �'�'+Ir�' O .,�.�f.7_ � � t��'�t � 1 �f•1( � ��. � �,�`� .. 'r" .ti i ` ' ��"'Y ��\�Y; LL�c�'.O�>�'�� d• � ; J%C,�.r'. I....�. . "i ��jd 'F�� ,�� .I:• � j� • �,.� .,.�.. ,F.`. \ ,�. �.w.�.?.� ��I� � i �/�,r ,�'� ,� � ..� � . �1. �,F� n�"� ; � , �� . . N � �� I � Ia �- � ww � {, i �v w � �Y A r.�_ t 1 �, .�,.: y.- f t �.i c �'c� �� .An � � . �� ...i �.. / .y� �� I � I i:: ,� ' �� n ¢ r, '� [ .`.i� � ., . •m'` y `. w `4 1 _',t�� . y,.f � -a �,� hy-' I r � �.... ;.� ��i !'i�' ..� r . ,;,, � V A�N�' y� Q �,y�,. L.: �; �, • y,,..{- o s.,,;_ �I.�-, I '"� �„ A � _.+ .�' '" t�,° c � ti=°" u ... F� � � , M� x �r .. ��F �.�'" �}�.. �!�� ''�`? �...�e �1-�:.�� :ll �.. �..4 r" �-V '«�n_ 'f1�Q .�N ;� � r Y Itl y:, v�o � t . n',�. � . if , ^aa '�" � �w � ' f: _ .�r y w , � 3 a a 1 f '�i> I � � . � „ >'.' ¢+� � c � r � kr ��v-� Y �:�..: �.F^ �,V ) ��I�? � � ,.H Y�� .�:,,�. � . �i y Y�j J. _ ,-♦ y: � n ,�� W t'- Z ., �^ l� � �t�.R i1 1 � F..�� `7"r 7��I�l �i,/' ,� F (j� Wn _ � ,.y k rti `��c C> b W w � � :�� 14 , 1 i`:Yk7'�, I �j �� i, ff �yd, � .I. r �:.- ��'` ."TJ��c�ni � c:T7 (n ..,�,q . �k 4 .'- r t�cv�y.., __ ..�. 'R��+xQ. , i �, i. �I �� - '�-(- -K �:� . � � �., � .� ��V ° i . .vw� �r . 'i:�t .,l! �;.�%r �. ��\7��,.r _ ��..,I�. //r 1,�, . , � � -u. ��,. � � �. � \k_. +t� ..,�.}� ,�- °, i?i�.i t7 m ai� ui � �_ � i �r. � .. T . , . e � � .. „� .rT•.�•. r�. , l,',�p�,�. ,"�`�wyk. i, t ..'i7 ! '��.,�I -.f � �_�:. J .��. �1. "'� .�.��u`c�.DiL,�` �� ,��:..,. �✓ "'��' � ..:,,}.�� . '. �.J"4✓'�, K + � �' `�t,y 1 f '� - -i� LL'T� .y� r.�. n ,i , n� � � /� !sr� � � ;;,,, 1 � yL '� t � �/.� I "� �a �n;:;-�n -�w o. p � �' ��v A �� , �a '• r' � f� ;. 1..�'�i i l�. � �lt _.. 1 � ��' �� _ ro - :j�i�U�:n �, U i r`�� ` � r ;t �.� •�, ' I ,�--'av.11 ',:L i.. I� I ' �// � t I TT ' 'Y J , il, � � _ � � � r i _ � � k �Y � I I Y �� I� - 1,1 1 �,��l�_�,i � ,a / , II I, �y. �i �'. - �% V [. � � .. � il.. � - 6�j � t' � ;`� / .�"°� ,�J * fg.`I � �-�lL�„� ,, t 0..g\N �.P k� � . . . Y ,�`� = r a u t ,Gj'Z '�' Q ��" � � .,� �,,d ,l �<. .,� i � , f'" \}a� � i� r . o � Jor O • r'' , A l.. � � ' o '��i �'��`" u � ,�d.,� I�4..�; .. � ;!, N.(��v��' Np� ��i.� � � '�� ,I ci�J��j°��C p�, "'N 'k> � ' .. I f , r � I �,• ,Ii - 0 �� Q��,i � ��` } - I' r. f. °fA'4 ' � aiy S � �; a t' .Ir �; i � -r A G�� 1-�. ,� - i __.. � _, _ u�t�n y" �'� + e : . r�� - .,Aq� � .. U �... .... .r _ ' . ,��, .,.+. �i Y� I . .I � 7,a..,V v p u� C � � „ � f� '�y. j "4- � _. Y_.n�ni.: i-v J . • �- �, 1� ,f � .r. + � � U - . \ r �. 1Tt p��y ,s� 1 M .!•�� 1 �I .� t��V'�� : 1 l.i.'� t . �. ��._ .+.u..�.L�,,..., N I l� t ' ��.1\ .I�l��i "� � ' � ' ' t � I 1.,..1 i ♦`- 'V �� "�"�i�i " -' 4.; �, .� o t_. t1 I 1 . I �� t ��.•{ � y, t`� '�. � , m v A � �' y+ ii tl� p�,�' -•• I ..�• ;L I . d. . " ' _' _ �� '-"n�p a�'^`> � � � 1 + �F'�:� i', wW '�'�$ �,?�'.�" ��......�..,- _"" 1 ,,,�•rP.w+ �t` _ `�'.' � �..r.�._ ., 1� r.. �" o'°C y C S�'=Q � � . � f �j �l� 1.��.} ��.�_ .�� "//.�� —� ...''�+r� .��_..:. 4 1-f" .��..:1 L.._ ---'I I � ��.N,QN�„�' _.._. � I � � �� .... q �� .. ..'. �r." . , v X>ro 0�C 7 L v x �� ' �}� � ,��a l,1� � y .{... wi 'Jdil ....1 ..� 1 l, "��,�V, r� �,,,,r i r I a�c ^�� y � � I ' \ ... _ _ r1 } / C 1 `m tcc , � ,,;�.,� _�' ( �� J lr I. ' ;: t*'I �� ..-. . ` , � \ l �� .� �I �,., I,. w::.} F .:_ .•,'� �q I '.[�f+ -_��.}i � �J/'.'Y4�"�-'7�-�.--�tq_ N[l.. (��q.. ,�`'� ,. .�.__,,,_._..� y`7i�a�-...�...�'..'..._.,..: 7-,f ..�«j i _.. ... .�.__.. 1 r .4_.,_ 1 .,J.._a''fT;.f. .....a I� . �'��I . µ (�' "'1� i f``f.'f`��l!� _.N �.. m__ ., � , � �' . � - r v.-. ' . . � ..... .. -'��.._� � r _. . . R� ,n� m ._. / �r � _ ' /fi� • �-� r�PT' ` �� . .�� .__�`��C-- ��j �_��.\1it..�t,,}��ti� � S „�• s �' �� ( " t _ ':`4 ' � �-r�-�� ,:-��'��h �r-it �, r t, �.a �`� f u . r y�. � .( � I�� t L�--i.��i LL '�=1, �: �� s 1 � s �. sA�y��t 'i,F,,,;- ��. i� ' }�Y �'�J��4^��. �'Lr.� �-��,,.�,�� i"� � - _' * � l i- i� 1 � � �!� f ��.' � iF.. � .,`�:. ' S e'� - � "�.�. - - �j--]. .��., 1� :! � ;� �� y } � �`. ``- -�� , �F. ; '' �., �,r,�� •,�+r`�(� � � -E �r��k. � � �-. a�..- i' 1 �� i � \,�,.� .. -. .,� _ i �.�r��.�.�.� � � �-'. r� \. , ,} A � �." ;,� � tf� ' -._�� l . , �� `-�-- ,�;�;iy; -:�-_ � '�� i ��. ,�► , 4�� . r� � ;� ; � r-, :-i( � _ � ,� 1_/;r r. ' S'•� :.-.� �: . '' .�,'r ' Yi �`� . � .. � � '�-1 / . , : j�� ` � _ �; a ��ct � �., �-1 �. �l E -—�. �� -�'.i3. . j j ��r i. .u."'f y - _, �f--r�.._..� a.r.�j-�± ��i 6s � �.' .- .�. -. . 'i .. �. . - _ . ._ ' �- .. ��t - t_, 0�� _ t . � _ _ � - -- y _ � � F.Y s £�- ' L . ' g��'., �. \-�- ` ! 3 • ��: f�-_�``�--a{"�__�{ . �t r 'F � �— t +F' � �. �. .� t Y.--�� f � �\ � � � �� ` t l \ ' e" _�� -1' �s, �� ' \. � -_ _ .,.�. � {�a t� _ � '� _ t`'� —, r ' 'c y. � `� ��.�- �1>�� }. � �_ ci�:�i !, i 1 � `�* "Q""r`_� �; ` 1 {.� •� _ � f�j� r ... - ��.,_� tT x � . _-' - F.. .. .�� . � �� 2 ( --� L �. �i � �; [^ -�i.�l�` \ J �i ��E .wi �i ,f;. �t s � �� =E.�' � I ��a �. __ r.�...,�.:--a � _ : i : F� - "�a`e.� � ,��`...�'t - 1� �7�'{.��.c�!� .� ��tj ., `'` - �� f�-� y� j 1: \ ��' - G -�� .}� F-�_ �(-'..`-�y.� i - ,_ ( -. `'�l �� _}7-�� =.�� I ' i� ` ✓ - �' .,} � }1 � -' -.:i\ �� .� �_�-. � 1L� -:..�'- �'!_1�` y��i��l,��__ � � i � " �= r s. • �� ` x ., � , r . ,F �. 4-- 'a. —'�� ,; `---� ---t-- � -�- .� ;_l Z� .t; r' -a� (' 1- � � �rl�� # 3`l�� t!\i� � � � -�`� �- t 1� � - � � �j.: � .\��: �� a ,,� \ �.- ) s..�1 7:�i'� � �_ . p'�. i� , � , � i-, �� .� i � =��t�J i. �ai��ti �- �_� t ._� '_/'.' f T. - �`• � ! �`�. �,� s• _ .t'`. .l� �:= �1t, t� � �.� �i f� 2 � � � � 1 �� t � .tr.. � �`• � { �1 _- ~ � � �.� 'j � :�.: � ,. � �- F� � - ,/..+ � � ` . - :{ � __ t � °r �;j ' \;�:_�� ;:'� " �I � ` �A . _ ��_- .`�-'` 1 T �. /� _ ( '�4 ► _ �", .��f g ' 'I� 1 ...y� '� `` 5 ' . _ -t .7� _ �� - �'\ `�t.: �, x � ..l�r.a'r `'i�-� _ '- •' ` J'._ _ ,` , �',` / '.._ — ` r � n� ��\ \'�. _:'t"Y f i' '" .- ; "� � . "F. �. "� �. ._ �-. �.Y �J . . * -, �`:; -� _ \�> ►� ��e_~ �y�� . ��•_ �� -.�:� ��_. .._ �" �F< � �.� _ � . � � _ � 'I Y i � •' �J _� •�' �`' � 4'-��_ . � � �} rt ,� �.'�� '+'��- - �i� � t\ - ` \ � _-`j � •' . � �.�'r- � _ '�i __ � ,�� Ti _ .: > •-. # � `< .jr � �� v '�< - � � � � '� - � \ !� r� �, �: Y'�'',t' -. E ' ji! ,� ,� � � _— - ., - �9 � � " �� . - - _; :.. �� !i f�, �\� � :�\ t; ��. .� .�: -� � F `'� !-.. � . ., .-, ��.. .f� _ �( t 4.L�� : '� i .Y_ /�J � � �.._j�'\ i _ f i �� } ` � ` ��"Y �I y i�: i !h�' �' 1 - - �'Y� y. ' ,� �� 1 . ��_�.� r � ' - l - � i Y �! i� � ` t " � I !�'j � c � 1 � lf�i �ni - • '� '�: � 11 ' ��r �. ! . .� 'I ,'J�� — _ i r �^ , i � L 1 1 � i .. � - �A � ��C:J� ��_. o : f �E �� —J� ' 1 � � . , s` - k �%;�; � ,: I • ' � � `' ,� `� ��J a l ,, � � � � � � �� - � �i:�� . ` n;� ��,�;`, — - , \ �J ,�� , •i J , .�: ! `�: 1' ` _� I �' � f�� ;`=' v . , : . , � s4 ��3-.� - t �� :i;ive areas dis- One- hundred-year tioodptalns extend be- \treams and 100 � C!�' apvroximate. Yond those shown on maPs. Flood In- �) �-�-y-�-� ��2(Wittl Salmonids) that have not zurance Rate Maps do not always show the �nt on a de�et- iloodplain to the headwaters of 5<<�m5. year Floodplains Gass 2(perennial•salmonid ere tli(ferences trated on these ,the dcWd� pre- US6 Uf1dCt0fi�llil¢� ot the senzitive �Sensitive Area lOaYear ROOdP181�15 • • • • • Cless 3 — — — Unclassified 1 1/2 o t MILE ��`� - � � STREAMS AND FLOOD HAZARD AREAS �� NORTH SOURCE: 1990 KiNG COUfJTY SEPJSITIVE AREAS FOLIO EXHIBIT "F" UPSTREAM BASIN MAP r � � \�;,` � �� ` � � 1 � �ti , � `� . . `� �` ��i'��11�1��j� ' 1 � < �: � 1 `tl1 1 � , 1 � � �, � _ ' � ll �� 1;��.��'; 1, , � � , / l � � \ s1� 11� t \ ` � � :�'� , , _ . � \ �\�� , , i ` ' " � yti, ,t �+`�.,� i ` � � � � . � \ . � �, ,�, �� \ l 1„ t�� ti t 1 � ,, � i � ' �.� � , � � 1 � 1 � � � -- �.�.,1�� ti � �� l � ��. � ' �'^ �' , • } l � � � . . . , , � � ` ` �— . �--�-�•__ �� ,��1 t c � �`, . . � � y� ti �,� -, �, � � �-- _ � r . + : � It� �•1�.� � � �� . 1 , ` � � � � � � , t� �t .:_` � _ --'\ = .�.� . \ \ --� I .- `, ._.r--- � \ �, l, \, 1 ,., �l� � � � , _ . ` � �.�� -. � � � \ � ,� -. � � �� \ � . � .�� `�.� � ,\ .� � � .� � - 1�� t ��\ �� ` , � '_,. . \ � ` � ,t'r' .\\, ��`�� 1 �� 1 � _ 1 , \ .� I 1 i; � \ �\ , 1 �, , .� � `��•� 1 �� ti \� �� .. � . ,.. � � { ' ' � . . ` 1� 1 \ \ l � �\ .. �' � 1 �l , \'� � �,,``` , `�.\``t� \ 1 t�1 1`� 1`, �� — � �\ \ ' , �' ` .`�`1 �� l`\�,. 1 . c 1 \ � , _` `� ` G:. _ � �.i ` .\� �� \ � \ `�11 l f�, , `��\ \ � � ` \ \\ � \ � � �`t � V� � 1,.�`�. . � � 1 l� � � o �� t � ,, > > �:� _ � �` .` :f, �`.� ; � � _� ,.� `1 ;`11l`,� ti ,,�t\� \,, ; � l �1\`,\l\ ,� !'��. �.- �` � \ ) .�` � �; \ ,�� > >��,��,1� , _ \�,\�\`i` � ' � �.�. -� �•.`?�' �t � �`��•�� '�� \`,� .� _ � � , t � � `�\ \\��\ � `l`, � Y \ �� 1 \� � '7 �`�\ � \�'•.\�� a�•� . ��'� ,\,� I � ♦ , � ��\� �'�. � \\�l�'� . \��,\'.��`` \ `�\,� •.\ . \ .4`� ` ` � `�� \��.�� 1� � \ ,` �`\��i "`� � � ' � � 1\�� ,\\� �\�`,� � �. \.1� `� � ,, \1 \ �\`�\ •.�\`�� \t \'' v�+^`1 �.` Tp y. � ` � � `�\ �.�ti`�\�` � 1� ��, �� \` ` •�.� , �, � ��~��ti1`a1�t`��, < � t`�� `� � \, \ � \ �� \\\�= _ �C��.��.�.�� > .,,, � �--`!"_`` �_ , ''_ `;\ ` _ �w ��" `��,•��`'1P'��' _'`� `i- � � �� _ � ��\�� . � � ` � � � , � 1 \ � � � ��\��' ''1�''` � U '�� - � � , . � _ �-- �`.1. ��. '� ` � �� ,ti\�.� ,�'1, ' . � !� , -- ` . ` . : ` r • �.\.'. �_-_.,-�� ... ��\`��\�� ` � �'\�'��'' ` . \\ � \ 1 � ` � � � ` � \ \`\ • �— '_�="' ' ��1�'.\��\�� _ _ .� . � � �. ,"' :,� . � � 1 1� , } � 1 L � 1 \ 1.\L�� '`�1� \ � f �1'`��`�\\�.i� ' \ �\\\�\;\�\ \ ` ` . � �. \ \-'. ,` f � � � , , , � �.� �..\ , � 1 �.� 1. \ � \• ��\ \ \ ). . ! t � � � ' � � � � ��i `� �;•,t,l�^'1•� � � � � � , � \`� �� ( �• L.` —r•� �� ,� \� �� 1 � !1 � � �` ` � � � �� 1 � � I1_ _ - -. � � �� \ \ �� * ` , �141�1�� .� `� � \ \ ��.\ �� 1��t��ti � { �� ,... _ .�'�`` �� ,`�; ��\�\\�,\`� � „r t � ,\ 1 � ,\ 1 �:..'�-�' '' � �P '� � �\ � 1 ��a ( .' . ` , r �` 1 � � �� \ `•• ��, � � ��__--��:� ��,`� , � �< ; y � � � `. � � � �\ -��`.�`_� � � � � , �` !� ��'•��`�tV�� . � � •, � - � .� —_—.� --� � � � \ _ , _ �.1��1��t�t� � ' � - . 4. � , ,: .. , � , ,,� :, �, � , � : l ',��.,. .,-.:�-�:��;�� ,, ��:;,;�,��-� rv ��r s �, . , �.�,. . � r � � � � '� � �,� �� ',. `� -.�-��\ �;. � . , �,��' K S I � � �--\ ` ��` \ � -�\ -, 1 � ` \\ �,�„\�� -� i �' �' � \ �1 ``� �� `` `�` �. �� ti� �.�,\ � 7 ��•- � ��\t�h� � ti ` �� '�.'� � �.`� . � �.\�� '` �-- �\�; � �\�� '` , i " �- � ` � -\�,_ �� . \ .� ��\ i ��i� i, � ;y,:.4 - i � � �� \� `� � � ��1 1��"�^ , ' ' • , ` \��• ,: r:• '- , �� ```��ti�\� , �\t},1\�•�� n � — .:} ,,,;�, ' ��\`.,1,�`�tl,, � '�i��\��\�`\ � . � t`\1,`,\ � - \`�\\\`\,`,\ '� .� �'�a , � . � , ��\�1��\�� '' �tit'��1\'\�� . ,r�r � ( ` -�'. � ` � ` �`��\ \� �i��1��\\��\� • ` �� l � ,` �``�1,� ��1 , •: �1��\�\\`��`. � \� . � ` �`��,� �,� �l�\��1��\�\� t r. . � �� ti 1�1��1 / .��1��1.\��. _ ` _ `-� �`'� ` � ! 1 ..., .;�" i i,l��1 '•..1�,�'; ` / 1111\�t`,��1� _ �� . �� l �til 1�>> �� „ .. .-. � �� ` � �\ ..� � {f�'��4ii :..•/, �`� 1� .��,, . �H � \ �1 � .' � 1 1�1,��\�\� t� �} . u�� ' �� , � �� :�-r ,� � \\�1�1�\>>��1�1•�w Y +' ti��- �;�11 1�1�1,�1,�`�l� ,...:' _..�.� i r.. '�,�� ' ' -` Il� < <,�.~`� ' �� , '1�11},1111}l �S� �11��f � .,• - � , � tl� t 1 \ ~ .� _ � �11��t��11��4�t S� � ��' ` ��; ., ,� ,,. . r�� }��y�� 1 �� :�-; tl�ill�111��r11�{�1 , ,_ . � _�J� ,t1��i��tij��It��►� --„ � � � � `� � } ` � �t ( � �� !flltlfll{it� " ti f�.-�. <� �� - � . ) ' � i111111111t � ,� ,- / r:. � •_r� ' / '/ 'Jf ' J~� ��tll1��1«�� _ '�=.-� �111t1t��ii>>t1 ��,1�� i.�( 1 .�f '.�. . . . `�' r �` 1 ` ' � \_ . `` t �� 7�1 t,� � 1,,'`�11,�` . . - � � � '� 1 � ."_:/" tt' � . >� .. . � . _ _ . . ��h 1,1��,�11t�11t1 � .t1 , � EXHIBIT "G" SCS SOILS MAP i .�m+.,� ••. � ,��, �+r � . r.�r, 1 �I `a ''� f3� n'�' 4v A,.. . _ �_ ?'?.. .-.:+j . w.�y av.. ,, v � .. ti,.``�� 1��. '.,�r,. ii ��9 ^. � �b `t'r�t�� + . �.r. W�A�1�� :,,��.r w1�i �y� �� i � � i�. �pq�� .. '. ',�,� ��x�� `... "+�,� '� �. , �.` �,��I, 1�, �^,w y�.., ' ; �.. , 3G: . `t' �ud{y � s.M"- y A � �� i .�� m �� ,�: . e ��" � -� �s�� 5� �.�o i . 'i*yYw a�',�' r'r 4 '� ,. , •. .;, . m > �4"�� ,� • u I � t� � f"�nk 'I ,i d�q�. k J� t�hw .. F�' 'Gh n 'L • � K�� n�p�'Cd'�� 2 ""' �'Ml�,'t'��;� � �i �m m i � ..� , • .� � �.• �� 7 ...., . . x . � i , . �� X,�� . � m3�,�a�ti�4 � �f r . � t , , � ti ��:- ��t�� Q :�iiy;�alt ,` ��Q Qi�/ "�� ,.' �� •• � . � , ,e, � . n ti r�� j � ' �.d � ''�� ' �� `�f�. �p�5 �� „�� Q '� �. II . � � . �•, k. �`+�� `� i �� s � n � , �r i � t �t, � � �� +4`e �`, �� D i , ° � R� � r , � � ` dr U a� �, � .. • II � ( ��f 1� I . "�1 r 4f "/ Q ��. / 1 � Q : �,�i�,.� .��., � , � II _m dN*�r ' K, (� l.;,( �i�ii� 4��} � �"�+� � �` �� a �� a .�k • t � •� i r�� ai ` �� ry N tP; F i ll� '' � ;�� :�� e�� i f ii ��r � I' i'� ��/ ^ 1 °;r: � .!' 1 . u Mo-��^y� ��1 i � 1�•,"�� k ' �'�` .'ot.� S ,� 7j- II �y.' v J'. i i N �) . �� r,7d� ��' f il,� ' + +{� •� � ' �' "�':�• ��y,;��6( � �A4'4'( �Y "T. .. {� i � � , �+' �, . I� �ILI. � q� � � 4'U. ' t � 4_., .kf P o j An r7 �� 4�� ,^ �A' W II :.� - . k �Jkt� � �` .��d 4� .�� ,�r fx pmp I r iC� . ��r l� ..A,. I �•. `�� y 4 � �k�� mr� i � d. 1 ° . 4 -'. 4 � Vtl�� i 4.�i I/ � f e . i ..��. � �� ( �`1 a�.� � v . '�,:� V /�� x;.�.: ., Qe .. .v♦ �. M� �oy{�r ti i +�- �. A � hy,"� �� ,� � � . f .�,.: � F"�`, � .'r�, �, . « '�,,,�� t ;r�� "� �� t �'� � :� u � �w�� o �,r,� -. , ; �� .%� r},�i j� +� ��+^� �� : i. � � � - � ��'�., � � �, � .. � � � D � �^��a �, ��6. �� •, �. �` , �ar :� n .��s t : rv:� , � '�� h A �a r a �` 5�^t", ' r<� ��e '� �� °' � ��t �� s�,, ' � �py�� ti.� �ti �Yr F`m t �� aa""o�� -�4� � '�I� �:;M ,��,U a �� t. � � g�'� d, �d��, V � � � _ , :�"��y�;; �m��' �� .� " ,s �±r��•�j�` -. � i ,�,,, .o� � ��w r d � ��';N �:�"'Zt�k . , .,, � � � " a ' ��: ��y �M� � , C9J1 � pp �;:CI . � � • . 5 - .:� _.m � '.. • ' • � w �C, zf?' . • . ... ,,,�+. . . ' � art4u . . , '. � :; ;� ','(`�o �4u . „ . — .. `fz �� , � v .�„�„�R.+. � F i�� ■ �dJ,+'g . '+ a�Jys��q�,�� s�?�J/i�1 �,y,ix. � d3�', � '�'. ,�� o +'�:� ��Q �7�;Ya a�A,t. � t0 a r;+� ,�,�, � �� T ,.7r �m� g��`��r�,,,t Yji�re�'� 'iu47k;ik ��`�,1Nysw �a"rr✓��''F.�Pit""rc�aa:�'`� ty�'..,�17/n�� 1 F�,: '� 6..r Q� p� a i. . ?� a� n°.�:,�I. �U"�m� �-J :a p - -- -�--- .;Y'�kSf+, , `a�� 1r3��"�r��+i��f�� , �11r��i ''v I . h ti3�ie ; �e I � r-+ �� °'-�c ---- � ��+,��'`� �°W�� x �� "�+�a��-.. � S�" �, " - ,�� . e++'°� }, � �„ ;�� ,—� � e� 8 ~�a^�. ��s� ��- , �,�. ��.;, � � , ,� r. � ;� r��' g��'S� t.h..�.. . M.Yy i �7 ��• N I'✓,b + ; v ' ` i � �+.� rt., � 1�� i I� � � � �� i�F.%� ,:' �'�. �� y '��.. +� .��• �:',.:I � �� ..:iyrt .°��g , ti ��: ,l ;�Q�' ~�\5,� ��+ti i ��1 ��k"�✓ ��-� � �� " ' �r�.��:� I. ��j � 1':.�� G //a� ��>Y �dp l �� 4. ^ � � f:�.� � ` ;, . ` i � ,� � � � � a ' . .�. _ I I '. / V �. aA y II Q �/ �� .) 1' / II 1 !ry ��rl " ��-�µ y1',y�'11 /h � uLL.�0. u.�rl�� ! iri, �� Yjq�gi U � , C1� 11t� 'S'�fhC :� �M�'� ivS'3'�;II TssaOi� �31d, d -� ! � � �'a�' ��l . � �"� � �,.q. dOQ . � r �,. M Q � � C �` , `� �j�.�`f'i �C�:>+� :pI� ':/II " � >�y��.�"b��( �'�':m j �` N ;; i O �"� 'LSTtu"i� .� a �� I y� :� �'� r J d��Y+"yr�,4^.,y,. ,/o a I �I4 �� '. E \ `•`VV �:[� � I 7 . • � a. ___.._ � � ♦ � ti 1 p . � Q� _ N.a � � ��.� ' ,•` i r . . "!�S}�R. �{r � Q�� .y�`�/ 4\ � i .��1J h .��.1 -\� \ � 1 1.1 �,..� �I �•♦ ....•� �� •t�t 1:: ��f \ , /.t Y/ �1 \\ h! .�F�� ii4��1��' �. �t � � v ♦ �� ` f' �/ � � u `�' y a �{..^«�.. 1�r �.� y^� \ •'�� ;J i Ir. i �N i '�(� y�A ��,y 4 �.. L F, �� / � � i r /� � � �:, % - � t' kr, �b u � ? �,� a d � y,; ��'w; � , ,�,; ,�a a. �U � J � _ ' � b� ,c y Y R ��,i ` ��> • o � , 1�" i asr � p, .=! Q � N�'�j . ...�.� C�� ' , .�• �*Sn�bW . � f�'� �i.'t ..�� . � .�Y' � '� � w ,� : � ' �� , .,:'� . j.GbO q a �''f�";� � 't� ,.. �.>, t E N +!n� 4 .� �� 7 '�� ,�\� f / . y^.� li-a , J.� ty �rf r� �.. �� . w � mrn _I e�: y o , � •, , _ � .. .r u 4L - � � M i�,, '�� !�t I s., � . ---� -^ i-. ,,,,,_ q �,� �,.. � �;� .,�_,_� �—� ♦ y f., ��i� I � r• �\ I _ y'�r °j- < E � ` *�� + � -C •I i�it �,- _fi'''� �� '1�, �� f �� S i��.s' � �k:µ �� :� ,�� `r� . ��s�a. ;�� .. �l,w�� ;< `� ��.o� � +�I . � . u V -��„ `,��; ` . 1 i � J�`� ':�ofl . H I r (J t I ` t y r � ,t rr� �� 41 I �,-8 �� ; � . ,5 �O :�. c k4� I { �� ! ° +: � �� a ,, 1�! 'r , �� . . r }n, _,d, �•'t�� j ),� _,�..� t , 7 � ii� ' bti; I�a � °If., � O� � ,.�. � I`aa �{�1.�F"i�` • a` " �w�� 'wt, y�t ,� " � �a, ud �m:�� ! � � • . � . ' sli�., �d' � a �' '.� a �� d�, ��, ��.G� � .{+ � r �� .'�•� � �! �i; . . ��,�, t i U i �� • ,_. . . �' ' '�7 � A"� , � . 1�2� +^ . "�"r '�p � u' � f :� � ^^ � ,_. � . �"r� �• ,,� r �'�r h I,�+ ��i� . ''�. � � � 1w h ^ , u , ��,,. , . � � An � �y.� . , r e� � � �v � ` �.,, -� .• � ,�, � � u ��. m � �W�".'.i� • .� �.r..-'-,��* • *� �� o-,� � �� f .. �+�.�' ,� J � � �:�` i� " : �` �h i� r a��,1 C� � • � � ,' °�� E �� s � � � .f �u�� - : a . �� , , o . � .� �; '.ud �� i� r :� " , �a:,� � ��' . ,,._ , . .,�.. .; .` � �II „ � � ,..+:� •-W... � � !� �' � / '� �•at ��u��4 �� '• , •' • •t ., � - � • � � ��-' i'` `.._ .�.,.. ' ��" rP��j� ...... .t • •�n �..'��r.`� uup ,•;:l _ �� •�r�,�. ,' � :.' �. . . �` � , � ~'�� ' . •. / Y . , .. Wt • ,�� '•�� w / �. � ^ M1„ • � V � .' � y 5'. 4 I � .:I .:�., � �i� � I I w � ' ,.., ✓ D , � ,� ,. �} I • � o' . � a F � � A w Be �� . . �e � � �� A� p ,. .�r,�� ' .a ,. t , .. � �.. , {�,�P G .. , �,� �� * � o .: .._. . . _ . � ?.. � Ny�•(, � �� 'O � . �o '\ �• .�i ,. Z� 'p� � 1`�. a �I ��r ��'� ,� � � "� . � e�r �4� �� O / � 'm �� , . �,,. �� . ; . .., a.,.� . '__ y � � .....� T _� r`w .r�.,.. � ^� �(�„�� N � „h�. ', JK .� ?�� is' �P J'.i�.�4•� -� _ ' �.� m: � � i� � ;e � �' , ��. V � �- _ "_ '� . n , '°�M. �, • • � :. , � ,/ � '�� a: iii u m u ,.. �HI� ��.J � ,S � m .. � N. , F��C9 � •II . �.4.%�f�/iN�i ., � � �a� �' !'a�i.n.Sw/� ,�Oli�. rsn ..`I \N . r �t�, bF � �, � �^�' .... ..�� 7 ••'iF 1��.�f-.' . .�/. rr�F:1� i . �� ' GIIIDE TO MAPPING UNITS For a full description of a mapping imit, read both the description of the mapping im it and that of the soil series to which the mapping iu►it belongs. See table 6, page 70, for descriptions of woodland groups. Other information is given in tables as follaws: ' Acreage and extent, table 1, page 9. Town and country planning, table 4, page 57. Engineering �es of the soils, tables 2 and 3, Recreational uses, table 5, page 64. pages 36 through 55. Estimated yields, table 7, page 79. PToodl and Described Capability ia►it group Map on symbol Mapping unit page Symbo] Page Symbol Ag6 Aldeiwood gravel2y sandy loara, 0 to 6 percent slopes---------- 10 IVe-2 76 3d2 C Alden+ood avell san loam 6 to 15 ercent slo es--------- 8 IVe-2 76 3d1 AgD Aldeiwoo gravelly san loam, 15 to 30 percent slopes-------- 10 VIe-2 78 3d1 AkF Aldeiwood and Kitsap soils, very steep------------------------ 10 VIIe-1 78 2d1 AmB Arents, Aldeirrood material, 0 to 6 percent slopes 1/---------- 10 IVe-2 76 3d2 AmC Arents, Aldeiwood material, 6 to 15 percent slopes 1/--------- 10 IVe-2 76 3d2 An Arents, Everett material 1/---------------------------------- 11 IVs-1 77 3f3 BeC Beaiuite 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 3d1 BeF Beausite gravelly sandy loam, 40 to 75 percent slopes--------- 12 V7Ie-1 78 3d1 Bh Bellinghan silt loam------------------------------------------ 12 IIIw-2 76 3w2 Br Briscot silt loam--------------------------------------------- 13 IIw-2 75 3w1 Bu Buckley silt loam--------------------------------------------- 13 II7w-2 76 4r+1 Cb Coastal beaches----------------------------------------------- 14 VIIIw-1 78 --- Ea Earlmont silt loam-------------------------------------------- 14 IIw-2 75 3w2 Ed Edgewick fine sandy loam---�---------------------------------- 15 IIIw-1 75 201 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 Vle-1 77 3f2 EwC �Everett-Aldezwood gravelly sandy loams, 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 TnC Indianola loamy fine sand, 4 to 15 percent s2opes------------- 16 IVs-2 77 4s3 nD Indianola loamy fine sand, 15 to 30 percent slopes------------ 17 VIe-1 76 4s2 KpB Kitsap silt Ioan, 2 to 8 percent siopes----------------------- 17 IIIe-1 75 2d2 KpC Kitsap silt loam, 8 to 15 percent slopes---------------------- 18 IVe-1 76 �d2 KpD Kitsap silt loam, 15 to 30 percent slopes--------------------- 18 VIe-2 78 2d1 KsC Klaus gravelly loaary sand, 6 to 15 percent slopes------------ I8 YIs-1 78 3f1 Ma Mixed alluvial land------------------------------------------- 18 VIw-2 78 201 NeC Neilton very graveliy loamy sand, 2 to 15 percent slopes------ 19 VIs-I 78 3f3 Ng Newberg silt loam--------------------------------------------- 19 IIw-1 74 201 Iac Nooksack silt loam-------------------------------------------- 20 IIw-1 74 201 No Norma sandy loam---------------------------------------------- ZO IIIw-3 76 3w2 - Or Orcas peat---------------------------------------------------- 21 VIIIw-1 78 --- Os Oridia silt loam---------------------------------------------- 21 II�r-2 75 3�r1 OvC Ovali gravel2y loam, 0 to 15 percent slopes------------------- 22 IVe-2 76 3d1 �vD Ovall gravelly loan, 15 to 25 percent slopes------------------ 23 VIe-2 78 3d1 OvF Ovall gravelly loaa, 40 to 75 percent slopes------------------ 23 YIIe-1 78 3d1 Pc Pi2chuck loamy fine sand-------------------------------------- 23 VIw-1 78 2s1 Pk Pilchuck fine sandy loam-------------------------------------- 23 IVw-1 76 2s1 Pu Puget silty clay loam----------------------------------------- 24 IIIw-2 76 3W2 Py Puyallu¢� fine sandy loam-------------------------------------- 24 IIw-1 74 201 RaC Ragnar fine sandy loa, 6 to 15 percent slopes---------------- 25 IVe-3 77 4s1 RaD Ragiar fine sandy loam. 15 to 25 percent slopes--------------- 26 VIe-2 78 4s1 RdC Ragnar-Indianola association, sloping: 1/---------------------- 26 -------- -- --- Ragnar soil--------------------------------------------- -- IVe-3 77 4s1 Indianola soil------------------------------------------- -- IVs-2 77 4s3 RdE Ragiar-Indianola association, moderately steep: 1/------------ 26 -------- -- --- Ragnar soil--------------------------------------------- -- YIe-2 78 4s1 Indianola soil------------------------------------------- -- VIe-1 77 4s2 U. S. GOV F.FtNMENT PRIN7ING OFFICE:19T3 O-968-266 � •� GUIDE 7'0 MAPPING UNITS--Continued iVoodland Described Capability imit gronp Map on symbol Mapping ta►it page Symbol Page Symbol Re Renton silt loam-------------------------------------------- 26 IIIw-1 75 3w1 J� Riveiw ash------------------------------------------------ 27 VIIIw-1 78 --- Sa Salal silt loam--------------------------------------------- 27 IIw-1 74 201 Sh Sammamish silt loam---------------------------------------- 27 IIv+-2 75 3w1 li Sk Seattle muck------------------------------------------------ 28 IIw-3 75 --- Sm Shalcar muck------------------------------------------------ 29 IIw-3 75 --- Sn Si silt loam------------------------------------------------ 29 IIw-1 74 201 So Snohomish silt loam----------------------------------------- 30 IIw-2 75 3w2 Sr Snohomish silt loam, thick surface variant------------------ 31 IIw-2 75 3w2 I Su Sultan silt loam-------------------------------------------- 31 IIw-1 74 3w1 Tu Tukwila mick------------------------------------------------ 32 IIw-3 75 --- UrUiban land-------------------'----------------------------- 33 -------- -- --- Wo Woodinville silt loam--------------------------------------- 33 IIw-2 75 3w2 1/ 11ie composition of these tmits is more variabie than that of the others in the Area, but it has been cantrolled well enough to interpret for the expected use of the soils. �� - � �I I� . jl I � EXHIBIT "H" ASSESSOR'S MAP "� SW 8-23-5 _ i 33i.B��_ � f: .. 6 .C.. ,. _ - r o0��!-iJ C-�____ �-��il2s __ , zi:t v` `��.L_ rs �6.a . z �� i�_ •^� ''` � '' '" y t ' W W I, ;v :� 'J � � A s D i� � �e U �� m Rm A�°�+� � S i k �'=�9 � . � �� :ii f ...� r � k ,i m.� i �~ `t\ i.?�'++� I �Y� G �` k � M a x"{' %•'• ��'�� .:q: �� Q � I a^ •��: t�• /..+ ..� �' .• +�;�! 'n� � � ;., �.i��,,�, I �', ;� Y� � �� ' A ';�b, ..0..�� '_ - __��~ Oca i F,}a o .° (n � ?�� .., .. � � �.; � 0,,,�. v� O � � � -.�=�.. . - � rn �.'�� Y '.:,. . ' �'�_.... NOUSER Y 4nv o�ON, E L M � �C (n Z S�'�SET l"_ . .... ,.».. ....,. "' �� -C ♦ , �Y�, T � i \� O� � � � I'I _'�)e ` ,eb t� *r." � � oi�, ., rf4�1 Y�,. e��O y�A �4 �w I. - Cn ••C� 'i x a' . � oe L�` y ;�1��. 4, 8 ,•' � � , \ c�� c� w�4 � ' U=� ��, �, �, u ,�a \J� -e �e\�4 oa�+i �- C _ � j �! ��• 'A i' 1�+ �^ -t oe w,' ., � • 'V� f ~ ,� "'�\ �� + s}JCr S.SM,.i�'. W��QQj . ��`r •v. 4 v�\�\ ,e A.�� F - t� ` ..t14'%x'"'�� `""y rp�`'••,' `E ";;\'' .' � yy H 0 ' ' � -�; :,..: : •:\, q�...,cz:.,••,, W� .�:'•�` �' � �� +'��:„• i � „ _. .,� 'th _ `,�,p s: • ��.� • y , „�, ;� , _ o .. , ,.. r.r .MN ^.,r.. , i... i.�' y��~F t}� �•r�' �'t'O,2 �'-. •'a �� y�'r• �l ''i C �«y � T .. • � � A a N .,,�. �� \� . ��;..;�y e �-. . ,Y. - � e z, ��s'�,,..oyN ��4� �t,�"` .s'.. ,` �,1. ., v.\��M1 ` �� r�L N . 1 Nym yg r '. .4. �"tt''i""=t y_�. - �''� Q'NN�N ,��'j �' �►i-°�i �� - � ,�,� ----�------ - N'%t:J`�� 3�d O,t7 r ,,. .. '�� i _ j °-�,� � ; � ;i W` .��. .y,� �� +'�, t 9 ` nd" r, r C! .«. �k ti G '4.i ro.� er•c�"'� ,.w.,.,•" .,. "n..� ••,r•�� ' R - ti6 *� .��- ` L� �� '�'y:...�, y-w`.�'^ ,.. « w � q�r� .a d�;1 u �; '• � � � ' `'�s"; � �d� ��s , � �.'i�,- ti'ti� � � ,T ... u�+•r• •'� �'Y�o e v1 e\v ' ± N N3 06 oN y'i°' ••,' � � � i ,,. yp j, - ITI .. s�tL +"'s� �+ �a � T�� -'� � •t�01 0` o .,'J g NdR�ES�GAR E HOM t R5, y��~ ^` . : N� .,'a, F ,5�, '�. • � pN r^ �I i��'M 7 `' - S%•ab^ '• - � 6 i � � ^ ,� �!`7` O ��• y VOl.3�/J! _ ,^'�,`'e: �'J+}', 4 � � 9 h�"1,.. � I�� 5 �i �, :�"Z BN a^ i7xe.ei�'�' �a n�i4 �4� �5,jy\ ,�N Q� k•:�� ` �� , �� 54' '+" R ^n Ri � y-` ON90N WiY ~� +�,'L V ea•,m ` 1=C _-� "NT:�!•O/C �.��_ l26.e� � w��.: � � W � NE 0� R �� e.00+ � '•• sEo e`t, ... ..............� Y... ... ., ««a .... � a"ea „y a :t i ♦ i` �ti. �a r ��,..i �..��.�.. y «� � . N i e �'� • �T �,w -.: ,. " E F "I W .�� ;,` rr'. •`•`•• �•�`vw;. '` � a, V��„�� i� � t l,m x c ° '�'�,• x�t�3�'��E�E �• cj' ' � y 'w,�. w.;•:'.�%�'-�i' . v° � � > m Q~. �ti,' .w �C �V' "'� !• 'w'`•' d''��^„ f � '•� Y 'M;.• `• - Y�V�o iY.= J. � 'P tA' POEEN ♦�� w C°1 WY� "'y�,..,, ' + �`4 e4. . � a .. , �°. y'a,a ' •�'.0 ! Y EVENE . . 6 "�. ws S d . i ;q ti._ ° _�. b A.N..,�0 , � ? r ^ y` �+y,� ''� o�a^di�'2 .d r� .•L�,�, eN....' i m .,..��. �,�. �� 1 N y��3N�� ,� ' � < i,,�;i j��,� �j 'iF i e N 7 1 / ?M o' s .�rt'�� . � E " f . 1 � �.�`t � �''f� ati' i' , , I�: t�Pl '� i `+` ;, e .""`, o'r'P ° `t d : ~f ei f=a�s °yE� � 6,.. s.6 ,��,Y � N�SNd l�l �'1 . ' � a.,' �0b� 0.�� ?e i `' 6N x S V�'� ��i4. O�e O4- -"� p � ��y�.= y =�L5 N1 �\•'� �° �.S n� �R 4� ' 6y� , a�. � � � � � .� ,, 't `E � j ,N �. ro `�4 � y � "� °:� t z � im t SFtW....c Y ya ^ �'liNNV, ;��`" � �� t �� E"a, + '� ,.. s�l.�N � +�'• �� a t ck r� `^ �Sb: t,`�}'�Y s t''m ,,.. � .., �o r�l _ m Lt�a "��• • y C� . .,� _ sy .� .' ..,,t� ,4Y� !�S- f ' S � = y S�, �m � w u S,; � � . : • Z��m:� �m y F Fi ,,,..^^y..',� � otisv�to L` ?u Z�e . °", W., c,. • ? �? _ , e'°e^: c°., i �`�c c e- '�i �°'rl "'•�i+'" '�Z :io 'FQ'� ` � � s ': _ �a ..c: GT�'., a.• 1 �e� ` d? ,, � �:`a �� t:Nh: �: �� e�i° +E� i �J= �v i p-1 j �+c'� . + `'.w w �4�: r� ; ; » � � l e ,' �. :��i t�^. . . � � R a e 'i�a�t T fi i•� �,✓, ' '- 1 y�e , ~v 4� Z,y p �Y. !.. � j i � „ t. ��._�I'BLAINE C.�. GVE NE : ! ��7.- !r-V`�{'"' �E a ITl i s , 'titi �r'+ H . He A� •�C0 �4k e i e'�'S'' � a m °i 3^ � � V c zJ ,� xa•,�• •�'o,•�r ` � : ,. `� .A• 'ti�P !M � •,. .. �� * ,�'• ' a�tQv , '�'ti:'w N m� _,� � � . �y�M•�`4= A.� i �. 1•� a �� aS/ • °►�We r! zp •�t;G a' v�.,v.n fe • 'era �; m ` ' " *J n`, �ti� � m �n ot ° ••w � p` + t! 1�'Sm' 1! �t �'0 ' � � CL''g��p�j y0 0 ` `y.e�` ,V NO .� � a =•.`.L�Ty t. . A }� . .W�. � v d. ' `iw� ' t ` t � � � F�6�' p � } �r o` Y%.•' s •�so L�� .`� � u4"c ''� Y��i V• a ' 1 V%..•� = r"�t. k�e . a'y ki�t%,. �,. 4+a (�N x .Z � � " ; °` ' .•' c ' +�i „ A, t� �..': °*6t ,j1„ R - °it s: �; `�: ti� ^�G: +i; a e "m,n �� s e E<� :„+.4_ � ✓�.;e ^ �,�V � *•^`,��4 •i� ' `'` ,.' �'� ��5�, +�� Y , ,.,...W ....,,. � t '"��/t A��_ � '� x;'4t ,�a��x ,, O� 8 , ,` `k�N r» - , ,<y , �- �' _` u 4`a\ s- ,d _ �«,' ..�, . ` a a" -,i ' :: ; t y ;� �.ti d N�, .�t1 •�� L�a N �' • ' �i.SW t`yiiZ � ,.Jkl f Yi" �..`; N r��W �}�o"' � A �� '`� w .f:4,:� � ., ati.;'e �� \1ti,� �.. 'L�k $� k r-f �} �a �. ♦, �"'. ,�t N yL� •i ''eh0 `it' `ts+4y1t •s+i � \•� �� t''�m`. {'�. p`'o ~6 h�H CL „�r�' J'•.6, •� ; i, •a •i:�'W �~•�SON .I' '" 'bJ � ... ..� �guf Q 3� . ' j:�;- � k� Y� !? ,r• +��,'' f :� � ;y �s.�,,• •."a� � bP� NE ^ ' , � o ��,, ��. ' `�,2ti�t•R'k;:y �"�L� a O ��Ym D +F�kr k^ C4MA3 av N � rn C t '�+ y y, �� ^ a ''♦ :4 F� �� •.6 e �••s •� •4 ky e e �� 3 � .� �� `o y •�'i:: ,,. � . �. ' x ' p A� a ,/d H,, � , , �w `.�'N .. . 3� N : �1 �s: �+ 71 d ,..... bi t� �4� �� -� � "^ ' ��y A .t ,� ..,' (n �"'` :i oti �` ��' - 'i i c°E\" w�� r+��'" f w{, �� .,\} �+� � �' ,�� N o "•� �� .�! �� " •�}z�t+ ° ' � �«y� c� �6 �_ ,� • «'�' �' «.., �°. `a�.••x�71��'' I S�" h �` r t'k,� �. °6.` /, � t � �l.� D � �, ,c V� ��,< �•7J �' �,,� - t e x.� �( . C:� �":`. 6 k G - s ti;e" ,y� '�"+a ;y�:'e� ` �c" ! • :�;��+,• �r+t ll.� x��o.. ., � �_ �rx :�r •� " • ��;,r « m ��.F �� w�-�t, �_ y e ieF� . m i �' i_ yW �� . ,0 6�'s:� r ��F r •�3` R{`''�w�/ t �ry f.. �� a +r ��s1'��`�F,s Ri2S � m�� ,./ lP`N .; `�e=;FS e�` y '" 'NW`• :� „' `A F.`... 6 F +; � e ��3�,-, .;w.,.,. . y�d� a °s` j ; t't�WM1 ,F`,• t� ra oarroN'A E`� st � N , '��t %, "'P4,4� �ayo. ^:�-:i � �. `�', .�+ ',�' 3 s �,. .� ��.ia= .=� ,� L :`�`'° � u yi�1� ,� �p FF aQ- ^1 �e w � H O� •" �1 �i\ �'`;. F� � W I NOSOR Pl•NE "'.. ,� ��\ `! 'Y n , •}q� ', o°b ,p�c - xL� 3.��' {. ��N �p~ I r��m " ~• .�. ^E �� • *�� tl ,, r , �r � °�i d; ,tii� �' •�� i;�_ . it-W •'r. ' • �:' ` o �g� r e., �. - � : � 'lu •' ti. "edA`�� , Y . " '^� d :�i _�u '� 's:n �tE� �%•" y •�E••r $t�,��e 'a; ��'46j �p �'v.��. „ � �(�J i4 m :��W 'c _ , M`i •i. ' ��''- V� I 9� �^. U..V��! : F � v _ 'y� a t= r 5 „ �• t �yu` ,e °s:'i .. a _ •_ , N /� t��.., __ e. r\ ° a ..a� � � 'C Lb •4 ' •�t'�i a r9 _ Y _ z.• x V ; mN � a• �o e �-- .. .� m _ «•• cCn � ,�� ~�t • �� !� "; �` t 4..i t;,� t � . + °':1�..,.. `ae ao �o 's ,�� }� yV��u.. .... ''�� 'Me' '00'""#. �;: � * •t�, e 0.., e.: 'o �, •t eoMonos nve Ne, '- • �'. „ , �e « et �6 �r�u c.L'� �.� +r"� t+y t� �:. I]28.9' � ' �� N 00-�lB-O��E�, EDMONOS AVE N[ � ' _ .�^�.+. a '1�1Y6.f6�•L�°� � � yi i SW 9-23-5 �' a > '► ♦ • �1 r � � . . _ _ ___ . _ � EXHIBIT "I" BASIN RECONNAISSANCE SUMMARY REPORT RECONNAISSANCE REPORT NO. 23 LAKE WASHINGTON BASIN JUNE I937 Natura( Resources and Parks Division and Surface Water Management Division King County, Washinp on King County Executive Tim Hill • i King County Council I Audrev Gru�er, District 1 Cvnthia Suilivan. District 2 I Bi11 Reams, District 3 I Lois North, District �i i Ron Sims. District 5 ' Bruce Lain�, District 6 I Paul Barden, District 7 Bob Grieve. District 3 Garv Grant. District 9 Department of Publie Works Pdrks, Plannin� and Resources Don LaBelle, Direcror Jce Nagel, Director Surface Water Management Division Natural Resouro�s and Parlcs Division Joseph J. Simmler, Division Manaper Russ Cahilt, Division Manaper ' ]im Kramer. Assistant Division Manager Bill Jotly, Acting Division Manager Dave Clark, Mana�er. River �� Water Derek Poon, Chief, Resources Plannin� Section Resource Section Bill Eckel, I�ianaDer, Basin PlanninD Pro�ram Larrv Gibhons, Mana�er, Project hlana�ement and Design Section Contributing Siaff Cootribuiing Staff Doup Chin, Sr. Enpineer Ray Heller. Project Manaper �C Team Leader R�ndall Parsons, Sr. Ena neer Matthev� Clark, Project Mana;er Andy Levesque. Sr. Enoineer Robert R. Fuerstenberp. Biologist �� Team Leader Bruce Barker, Enpineer Matthew J. Bruengo, Geolooist Arny Stonkus, Enoineer Lee Benda. Geologist Ray Stei�er, En�ineer Derek Booth, Geologist Pete Rin�en, En�ineer Dyanne Sheldon, Wetlands Biolobist Cindy Baker, Earth Scientist Di 3ohnson, PlanninD Support Technician Robert Radek, Ptanning Support Technician Randal Bays, Plannino Support Technician Fred Bentler, Planning Support Technician Consulting Staff hlark Hudson, Plannin� Support Tcchnician Sharon Clausen, Plannin� Support Technician Don Spencer, Associate Geolo�st, Eanh David Truaa, Planninc Support Technician Consultants, Inc. Brian Vanderburg, Planning Support Technician John Bethet, Soil S�tientist, Earth Carolvn M. Byerly. Techniral Writer Consultants, Inc. Susanna Hornig. Technical Writer Virainia Newman, Graphic Anist Marcia McNulty, Tvpesetter Mildred Miller, Typesetter Jaki Reed, Typesetter Lela Lira. Office Technician Martv Coa. Office Technician P:CR TABLE OF CONTENTS I. SUMMARY 1 II. INTRODUCTION 1 III. FINDINGS IN LAKE WASHINGTON BASIN 2 A. Overview 2 B. Effects of Urbanization 7 C. Specific Problems 9 1. Threat of damage to property from landslides and erosion processes 9 2. Threat of damage to property from ffooding 9 3. L.oss of fish habitai 10 I IV. RECOhih1ENDATIONS 11 A. Mitigate current and prevent future threat of damage from mass-wasting and other forms of erosion 11 B. Mitigate current and prevent future loss of fish habitat 12 V. MAP 15 APPENDICES: APPENDIX A:Estimated Costs A-1 APPENDIX B: Capital Improvement Project Ranking (for East B-1 Lake Washino on and West Lake Washington) APPENDIX C: Detailed Findin� and Recommendations C-2 I. SUMMARY Lake Washington Basin combines the East and West Lake Washington Basins, which together consist of the ratchments of many small streams that flaw directty into Lake Washington. Most of the combined basin lies within the incorporated areas of Seattle and other cities surrounding the lake. The reconnaissance, therefore, focused on five small, somewhat isolated geographic areas on County-administered land. For purposes of the study, these have been named Sheridan, Bryn Mawr, Kenmore, Finn Hill, and Hazelwood. The Lake Washington Basin has been almost completely urbanized_ Expansive areas of impervious surface and severely altered stream systems have produced substantiat increases in surface water runoff and attendant problems -- flooding, erosion, sedimentation, landslides, and loss of habitat. Even the Hazelwood unit in the southeast quadrant of Lake Washington, the least developed unit studied, shows severe signs of siream erosion caused by housing developments upstream. There were several specific problems found during reconnaissance. There is a thieat of damage to property 6om crosion, including landslides and othez forms of ma�stin� This is demonstrated by debris slides at the edge of the piateau abwe Tributary 0228, the morc shallaw slides on the lakeshore cliffs and ravine of Tributary 0464A, and the severe hiliside erosion along Tributaries 0'I24 and 0'L27. T6eie is a thrcat of damage to property from Elooding due to t6e deterimatioo of some culveris. In addition, there has been damage to fish habitat where streams have been placed in culverts, where there are barriers to fish migration, where the natural features of streams have been destroyed, and where water quality is poor. Recommendations in the Lake Washina on Basin include 1) mitigatmg auient and � preventing future erosioq using a combination of regulatory measures (such as siiffening ', requirements for permits and property transfers and implementing joint jurisdirtional basin planning) and structural measures (such as increasing R/D capacities where needed, rerouting surface runoff around sensitive areas, and employing instream erosion control). Recommendations also include 2) mitigating current and pieventing future loss of habitat with plannina and regulatory measures (such as developing v�;ater quality standards and treatment strategies and devetoping consistent b idelines for protecting wetlands and streams) and structural measures (including the elimination of barriers and the use of two-cell R/D ponds). IL INT'RODUCTION: I-�t«y and GoaLs of t6e Ptog�am In 1985 the King County Council approved funding for the Planning Division (now called the Natural Resources and Parics Division), in coordination with the Surface Water Management Division, to mnduct a reconnaissance of 29 major drainage basins located in King County. The effort began with an initial imestigation 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 probiems. These initial investigations used available data and new field observations to examine geolog}r, 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 remnnaissance to be completed on the remaining 26 basins. The Basin Reconnaissance Program, which was subsequently established, is now an important element of surface water management. The goals of the program are to provide useful data with regard to 1) critiral 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 problems� P:LWB 1 Lake Washington Basin (Continued) The reconnaissance reports are intended to provide an evaluation of present drainage conditions in the County in order to transmit information to policymakers to aid them in developing more detailed regutatory measures and specific capital impravement plans. They are not intended to ascribe in any conclusive manner the causes of drainage or erosion problems; instead, they are to be used as initial surveys from which choices for subsequent detailed engineering and other professionai environmenta) 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 environmentai narratives rather than as final en�neering conclusions. Recommendations contained in each report provide a description of potential mitigative measures for each particular basin; these measures might provide maximum emironmental 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 officials 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 en�neering analysis possible oq a site-specific basis for any proposal. IIL I-�IDINGS Qd LAKE WAS�IINGTON BA.SIIV Reconnaissance of the Lake Washington Basin was conducted in March 1937 by Robert Fuerstenberg, bioloe st; Matthew Brunengo, geolo�st; and Bruce L. Barker, engineer. Their findings and recommendations are presented here. A Ovezview of the Basin Ccogtaphic and tand use features. Lake Washington Basin combines East Lake WashinD on and West Lake Washina on Basins. These consist of the catchments of many small streams that flow directly into Lake Washinb on. Most of the combined basin lies within the cities of Seattle, Lake Forest Park, Kirkland, Hunt's Point, Yarrow Point, Medina, Clyde Hill, Bellevue, Beaux Arts, Mercer Island, and Renton or within the drainage basins of larger streams, such as Thornton Creek, McAleer Creek, Swamp Cree3c, Sammamish River, Juanita Creek, Forbes Creek, Mercer Slough, Coal Creek, May Creek, and Lower Cedar River, that are described in other reconnaissance reports. For the purpose of this study, the corobined East and West Lake Washinb on Basins will be termed "the basin." The unincorporated County land within the Lake Washinb on Basin may be divided into five small, somewhat isolated geographic areas. The findin� and recommendations in this report have been organized according to these desio ated areas: The Sheridan area, north of Seattle, is bounded by McAleer Creek Basin on the north, Thornton Creek Basin on the west, and the city of Seattle on the south; The Brvn Mawr area, south of Seattle, is bounded by tHe city of Seattle on the north, the city of Renton on the south, and on the west by the ridgeline between Renton Avenue S and Empire Way S; The Kenmore area, at the north end of Lake Washino on, is bounded on the �orth appro�umately by �3th Street SW in Snohomish Cou�ty, on the east by the Swamp P:LWB 2 Lake Washinb on Basin (Continued) Creek Basin, and on the west by the Lyon Creek Basin and the city of Lake Forest Park; The Fnn Hill area, at the northeastern corner of Lake Washington between Kenmore and Juanita, is bounded on the north by the Sammamish River Basin and on the east and south appro�cimately by 34th Avenue NE from Northeast 145th Street to Juanita Point. 1'he Hazelwood area, in ihe southeast quadrant of Lake Washington east of Mercer Island, is bounded on the northeast by the Coal Creek Basin, on the southeast by the May Creelc Basin, on the south by May Creek and Renton, and on the west by Lake Washina on. Oniy a smail part of the shoreline is administered by King County; the rest is within Bellevue or Renton. The total drainage area for Lake Washina on is approximately 603 square miles (not including the Lake Sammamish Basin's 97.7 miles}. While this basin is large, the actual area studied during reconnaissance is much smaqer and includes only the geographic areas listed above. A totat of 13 streams were included in the siudy. The total land area for each geographic unit, together with the lenp hs of major tributaries, is as follow�s: Unit uare Miles Maj. Tribs Len�th Sheridan S 0048 0.4 Bryn Mawr 29 0464D 1.35 mi. Kenmore 2.2 0056 2.00 mi. Finn Hill 6.8 0227 1.00 mi. 0228 2.00 mi. Hazeiwood 2.1 0231 1.30 mi. These five geo�aphic units are distributed over four King County Communicy Planning Areas: The Shoreline Community Planninr Area, which contains the Sheridan area, is a mature suburban community,,with approximately 90 percent of its usable land already developed. Single-family residences dominate this area, but the number of multi-family units is slowly increasing. The Sheridan area contains some of the highest densities in the planning area: 4-6 single-family units per acre and up to 43 units per �oss acre in multi-storied apartment structures in planned unit developments. These ma�mum densities are located in the south-central portion of the area along Bothell Way (State Road [SRJ 522). Community-scale retail business is also located along Bothell Way in the same vicinity. Zoning changes are tikely to occur as new multi-family units are considered in single- family zones. Concurrent chanoes in commercial and business categories should also be anticipated. These changes, however, are likely to occur along Bothell Way and not in the interior of the Sheridan area, which is an established singie-family neighborhood. The general character of the area is therefore unlikely to be greatly affected. The Northshore Communitv Plannin� Area, which contains the Kenmore and Fnn Hill areas, borders on portions of the cities of Bothell, Kirkland, and Redmond. Woodinvitle. though unincorporated, is a si�ificant popuIation and commercial center, and much of the recent grow-th of the Northshore Community Planning Area has been concentrated P:LWB 3 Lake Washington Basin (Continued) . there. In fact, the Northshore area is one of the three fastest-o owing plannine areas in I King County (the other two are Federai Way and Soos Creek). From 1970 to 1985, the Northshore area population increased more than 106 percent, from 33,000 to 73,000. - The population is expected to reach 122,000 -- a 64 percent increase — by the year 2000_ Single-family urban and suburban uses are dominant throughout the western portion of the plan area, adjacent to Lake Forest Park. Low-density uses such as suburban estates and general ctassifications are found in the eastern portion of the plan area (Finn Hill}. , Multi-family zones are located near and along major arterials, as are commercial and business facilities. Areas of concentration include Woodinvil[e and Kenmore, along Northeast Bothell Way. Manufacturing and industrial zones also exist in Kenmore along the northern shore of Lake Washington and the lower reaches of the Sammamish River. Some agricultural land exists south and east of Bothell, along the north shore of the river. Continued grawth in population wilt be accompanied by pressure for varied types of housing. Recent zoning changes have been directed toward an orderly transition from rural and 1ow-density suburban to higher suburban and urban densities. Increased , demand (and opportunity) for business and commercial services will accomparty changes in hOu5ing. I The Newcastle Communitv Planning Area, which contains the Hazeiwood area, is ' sUrrounded by three significant urban centers: Bellevue, Issaquah, and Renton. The northern and western portions of the planning area consist of rolling to moderately steep hills developed at suburban residentiat densities. The plateau abave the Cedar River has an established character of lower-density residential uses interspersed with pastureland. The eastern portion of the area lies on the steep slopes of Cougar and Squak Mountains and contains production areas for natural resources such as timber, gravel, and sand. Old coal mines lie beneath Cougar Mountain east of Newcastle. The major commercial center in the planning area is Factoria in the northwest. The population of the Newcastle Community Planning Area increased by 41 percent from 1970 to 1985. By the year 2000, the population is expected to reach 102,000, a 42 percent rise in 15 years. This dramatic increase in population is expected to increase demand for single-family residences. Densities should be expected to rise first in the northern and southern portions of the plan area and subsequentiy throughout the central portion. The Hi line Communitv Plannin� Area, which includes the Bnm Mawr area, is physically and economically dominated by Seattle-Tacoma (Sea-Tac) International Airpon. Approximately 20 percent of the area is occupied by the airport itself; additional space is devoted to "clear zones" below and adjacent to the ;lide paths. The remainder of this plan area is predominantly urban/suburban residential. Single-family units make up most housing, with multi-family units generally clustered around e�cisting commercial centers and the airport. These commercial centers include Burien, Des Moines, and White Center. Significant strip development is located along State Road 99 and First Avenue S. In 1970, the population of the plan area was appro�amately 138,000. By 1980 that fip re had decGned to 129,000 (a 6% drop), and by 1985 the popuiation had recovered P:LWB 4 Lake Washina on Basin (Continued) somewhat to 133,000. The estimated figure for the year 2000 is 135,000. There are I dense concentrations of people in White Center and the North Hill neighborhoods. Existing development in the Highline Plan Area is substantiai and generally not subject to I� drastic reordering. Future zoeing changes will reinforce and improve existing residential ' neighborhoods and business centers. Geologic and geomorphic features The deep, elongated trough occupied by Lake , Washington was carved mostly by gJacial ice into unconsolidated glacial and �onglacial sediments. Those sediments reach thicknesses of more than 3,000 feet north of Mercer Island, but are thinner where they are lapped onto the bedrock of the Newcastle anticline I to the south. The North Seattle and Interlake drift plains (west and east of the trough, ' merging to the north) are similar in topography and stratigraphy: drumlinoid plateaus � surfaced with tiq werlying proglacial sands and �avels and lacustrine siit exposed mainly � in bluffs along the lake. Toward Renton, these materials are plastered over sandstones, j siltstones, and volcanic rocks of the Pugei Group and folded into a ridge perpendicular ' to the trough. ' The topo�-aphy, w�hich determines rurrent drainage patterns, was shaped by southward ice movements. Streams tend to t7ow north or south between drumlins. In the Kenmore and Bryn MawT areas, at the northern and southern ends of the lake, respectivety, slopes are relatively gentle, and till mantles the surface to the lake shore. The la ber streams in these units flaw directly toward the lake, and older sediments are exposed mainly in � deep ravines. Alono the eastern and western sides of the trougt► (where the Sheridan, , Finn Hill, and Hazelwood areas are located) major streams rise on the plateau and fiow parallel to the lake. Trough sideslopes, eroded by the sides of the glacier lobe, are steeper and generally expose the gravels, sands, and silts under till. The creeks in these areas are mostly small and fed by seepage, except where they have captured the flow of plateau streams. The differences in topography and exposure of geologic materials in the various terrains produce differences in the intensity of geomorphic processes. In general, the steep, high lakeshore bluffs have the highest [evels of groundwater seepage, landsliding, and actual or potential stream erosion. Trough sides(opes, ori,�inaliy carved by glacial ice, make up all of the Sheridan area, the w�est-facing hillsides of Hazelwood and Fnn Hili, and the bluffs west of Renton Airport in Bryn Mawr. In these areas, there is �oundwater seepage in exposed sandy layers perched over silt or tilt. This seepage contributes to mass mavement — mostly shallow debris slides in Sheridan and Hazelwood, commonly in artiCcial cuts but including la oer slumps in Bryn Mawr and Finn Hill and one large, active slump northeast of the May Creek interchange in Hazelwood. Most streams are short and ephemeral and have not eroded far into the bluffs. But in Finn Hilf, �eater seepage has formed larger streams; these have cut eastward, expanding their catchment areas and increasing their erosive potentiat. Likewise, one stream in Hazelwood has carved a deep ravine into the edge of the plateau. These large ravines are quite sensitive to further slope and channel erosion. Where slope aspect is parallel to the direction of ice flaw, there is relatively impermeable . till at the surface, so that more of the precipitation runs off into numerous smaller streams. The laraest of these have cut through the till and into erodible sediments below, forming ravines where sliding and channel erosion are much more active. This is P:LWB 5 Lake Washington Basin (Continued) especially troe in the Lakeridge Park ravine io Bryn Mawr. Because lakeshore slopes in these areas are more gentle and experience little seepage, the landslide rate is lawer than in similar areas. Slides of various ma�itudes do ocrur, however, partirularly where slopes have been underrut during road construction as along Bothell Way, Juanita Drive, and Rainier Avenue S and where the stratigraphy is particuiarly suitable (e.g., the old stide w-est of Kenmore). There are areas of roliing plateau in the Hazelwood and Finn Hill areas, and the upiand regions of Kenmore and Bryn Mawr are similar. Because of the gentle gradients and moderate levels of urbaRization, there are few erosion problems. Water perched over titl collects into wetlands and small streams, then flows to the lake; it is on the plateau edges that these creeks cause problem� Development activities that would increase the volumes and rates of discharge in these streams would a�ravate erosion dow-nstream in the ravines. Major hydrologic and hydrauGc features Lake Washino on Basin, as the name is used here, is a collection of small, mostly urbanized basins that drain the plateaus around Lake Washington. Most of the drainage originates as surface runoff from urban areas, witti b oundw-ater seepages contributing si�ificantly to the flow in the lower reaches and near the base of the bluffs. The hydroio�c response to storms in the basin may be characterized as flashy (i.e., rapid increase and recession of flo.;;s) because of the large amount of impervious area, the steep gradients in the low•er reaches, the short lenb h of each tributary, and the lack of hydraulic controls such as lakes or wetlands. Particular hydrolo�c and hydraulic features of the frve geographic areas studied during reconnaissance are described below. Sheridan area. Most of the drainage courses in the Sheridan unit have been piped directly into Lake Washinb on. There is a single open channel left -- Tributary 0048. The volvmes of flow and peak discha be in this stream are relatively small, even though the drainage area that feeds it is almost fully urbanized. The reason for this is that some of the area runoff used to feed it is now piped directly into the lake. Many sprin� e�cist between Bothell Way and the Burke-Gilman Trail. Si�ificant amounts of flow have emerged from these seepages and have ponded in terraced yards on the hillsides; this has undermined the subbase of pavements and caused the periodic flooding of basements. Most of the seepage is intercepted by storm sewers and discharged to Lake Washington. Brvn Mawr area. Bryn Mawr is almost fully urbanized, with new construction proceeding in the few remaining undeveloped areas. Flow orip nates as runoff from impervious areas and groundwater seepage in the }ower reaches. There are five streams with open channels, most of which have been partially channelized or piped. One example is Tributary 0464A, which has been channelized or piped along Renton Avenue for 30 miles. There is one large wetland in this area that was not covered by the Kin� Countv Wetland Inventorv. This wetland is located in subcatchment 4 on Tributarv 0464E at river mile .25. It is one of the few wetlands located in the Lake WashinD on Basin and provides flow attenuation and water quality enhancement for Tributaries 0464E and 046=tD. Haze}wood area. A north-south ridge bisects the Hazelwood area. Rain falling on the west side of the ridge f7ows into subcatchments 13 and 29. Rain fatling to the east P:LWB 6 Lake Washinp on Basin (Continued) flows into Tributary 0�1. Drainage from subcatchments 13 and 19 is diffuse, flowing ' into Lake Washino on at many points. There were few problems associated with surface runoff in these subcatchments. Tributary 0231, however, has ea-perienced severe channel erosion due to a combination of increased peak flaws from new developments in the area and the highly erosive nature of the soils along the channel. ' Finn Hill area. Finn Hill is the most complex unit in the Lake Washinb on system. There are seven streams that drain a flat, developing p(ateau. The gradients of these streams increase to a maximum of 3-12 percent as they approach Lake Washington. Most oF the runoff in this basin originates as impervious runo[f or seepage out of hillsides. There are several wetlands located in the Finn Hill area. Three are identified in the Sensitive Areas Map Folio (SAM� -- one along the shore near Inglewood Country Club, another in Big Fnn Hill County Park, and the third near Northeast 141st I Street and 34th Avenue NE. During the reconnaissance, 10 other wetland sites were discavered, seven of them on the Tributary 0??8 systero. The hydroiogic response to storms in the basin is typically fast, ezcept for Tributary 0?33, which is buffered from high peak flows by the many wetlands. Kenmore area. Flow in the Kenmore area oriD nates as runoff from urban areas. The major tributary in the basia, 0056, has been channelized rner most of its length. The headwaters of this stream are located in Snohomish County near a major housing development. Although the �adients in the basin are typically lower than those in the other areas, the hydrologic response to storms is stiil fast due to the lack of vegetation , along Tributary 0056, the large amount of runoff from impervious surfaces, and the small size of the basin. Habitat characterisii�s. Habitat diversity in al! stream systems of the Lake Washington Basin has been significantly reduced by urbanization: Long reaches have been channelized or placed in culverts, reducing spawning and rearing areas. Numerous barriers, such as cuiverts, weirs, dams, and artificial cascades prevent access to upper stream reaches or entry to entire streams. In many streams. urban runoff causes erosion and gravel movement. This fills pools, deposits silt in rift7es, and generally causes unstable stream conditions. Headwater areas have losi wetlands and riparian vegetation. . The most usable habitat exists in the Finn Hiil area where manv streams descend from the uplands throuph deeply incised ravines to Lake Washington. Vegetation in the ravines has generally been left undisturbed, and wide riparian corridors exist all the way to the lake shore. Through these reaches, o adients produce pool-riffle characteristics well-suited to fish use. Woody debris is abundant but often unstable because of high flows. Debris jams are common and produce ephemeral barriers to fish mavement_ In Tributary 0228, however, conditions for fish use are exceltent. L.ower reaches of the stream have good pool-riffle sequences and relatively clean, stable gravefs, as well as la ve, deep pools. Woody debris is common and stable; vegetation for stream cover is abundant. Benthic invertebrates are common and diverse, indicating a stable, balanced stream system. Only in this system were spaw-ning and rearing salmonids observed. Even so, a 6-foot-high w-eir at river mile .45 forms an impassable barrier and prevents upstream migration of anadromous fish_ Resident cutthroat trout occupy the upper reaches, particularly in the Finn Hill Park area. P:LWB 7 Lake Washinb on Basin I (Continued) B. Flfects of Ur�anvatioo Intense urbanization of the Lake Washington Basin has had an adverse effect on all of - I the natural systems within the basin. Large areas of impervious surface, channelized (and otherwise altered) streambeds, and the lack of wetlands or lakes to attenuate flows � have severely attered the hydraulics of the basin. Surface erosion and mass-wasting, ' increased sedimentation of Lake Washin�on, and flooding have resulted. Other problems have been caused by excavation, clearin� and building on and along the tops of steep, sensitive areas. Some development of this kind has destabilized larger uphiil areas, as welt. Environmental problems are numerous in the basin, many of them related to the destruction of fish habitat. Direct loss of habitat has occurred through the channelization of streams; indirect loss by using streams as urban stormwater conveyance systems (which I raises peak flov�s and commonly reduces water quality), the filling of wetlands in the headwater reaches, and the encroachment on riparian corridors (which results in the loss I'I of floodplains and vegetation). These effects of urbanization, as well as the measures that have alreadv been taken to address them, will be examined within the context of the geographic areas in which they occur. I In the Sheridan area, the creek dces not cam a �eat deal of flow, because much of the area tributary to it has been diverted to storm drains that discha oe directly to L.a3ce Washinp on. Therefore, any future surface water problems in this area will be associated with seepage from hillsides. The combination of steep gradients and artificial channels makes it unlikely that these systems can (or pos.sibly ever did) support anadromous fish populations. In the Brvn I�tawr area, much of the flaw Aas been piped, but to a tesser eatent than in the Sheridan area. Some of the tributaries in this area show signs of stress from urbanization in the form of sediment transport induced by increased peak flows and water quality problems from oils and greases. Mosi of these problems stem from the fact that no onsite detention reo lations were in effect at the tirne most development ocrurred. Sediments carried dow-nstream settle out in Lake Washino on, forming a delta that makes navigation and moorage near the stream mouth difficult or impossible. The worst case of sediment deposition occurs at the mouth of Tributary 046�1D; this problem ori�nates with si�ificant rates of mass-wasting upstream (see Appendix C for locations). Although the Hazelwood area is the least developed area of the basin, its major creek, `Tributary 0281, shows sip s of severe channel erosion attributable to runoff from recently constructed housing developments. Sediments transported downstream had settled in the lower reaches of the creek, caused t7oodi�g, and formed a delta in Lake Washina on that posed a threat to navigation and moorage. The erosion problem was corrected by the installation of an instream detention pond at river mile .35 and a sedimentation pond at river mile .40. These ponds appear to be adequately handling current flows and sediment loads. Other problems still persist in the Hazelwood area, however. Shallow landslides have occurred in roadcuts along Interstate 405 (I-405), for instance, and losses of habitat have been brought about through the elimination of wetlands (at the headv�-aters of Tributary 0231}, and poor water quality resulting from parking lot and road runoff. I �- P:LWB 3 Lake Washinaton Basin (Continued) Development in the Fnn Hill area began at the turn of the century along the lakeshore. As developmeni continued inland, new drainage systems were constructed and connected to e�cisting ones dow�nstream. The process created a comptex drainage system with many sections inadequatety sized to handle the added flows. Law divides between many of the subcatchments have compounded the problem and made it easy to divert stormwater into streams other than those to which the water would naturally flow. This cross-basin ditching resulted in one of the more severe problems noted in this basin during reconnaissance. Flow from approximately 75 acres of subcatchment 12 was diverted to subcatchment 13 when a new development was constructed near the ridge line betw•een the two subcatchments. The increased flows to subcatchment 13 caused stream erosion and sediment deposition in Lake Washinb on. Some of the worst erosion discovered in the basin during reconnaissance occurs in the Fnn Nill area on Tributary 0229A. In addition to the hydrolo�c and geologic problems in Finn Hill, habitat has been lost on Tributaries 0222 and 0223 through the eliminatian of riparian comdors and w�etlands_ The Kenmore area has been atmost fully devetoped. Its major tributary (0056) has been channelized over its entire lenb h. The tributary receives runoff from Snohomish County and direct runoff from 61st Avenue NE (a major arterial). The most severe channelization and piping ocrur along the major arterial where the road has been constructed up the ravine. The crowding of the stream between the road and the vallev walls has resulted in erosion of the shoulder and slopes. Tributary 0056 is also piped for approximately 600 feet from 61st Avenue NE and Northeast 130th Street to a condominium complex located on Lake Washington. This eliminates fish habitat and restricts access to upstream migrants. These and other problems are discussed in greater detail in the section on specific problems (below) and in Appendix C. G Specific Problems Identified The discussion outlining the effects of urbanization in the basin identified many of the problems found in the five o ographic areas siudied during reconnaissance. The follawino discussion p ves fvrther details of those problems and provides e�camples with regard to erosion, surface water issues, and habitat loss in the Lake Washington Basin. 1. T6eie is a threat of damage to praperty from landslides and other erosion proc.� active in the basia SpeciGc problems include: a Mass mavement, which oa.lus at all scales in the basin. Slumping takes place in the glacially oversteepened trough sideslopes, usually aided by seepape of �oundwater aver perehing layers. Slides have occurred in the lakeshore slopes of Finn Hill and Hazehvood; an ancient slump is mapped west of Kenmore. Most impressive of all are three prehistoric landslides, aU now lying below Lake Wahsinb on and probably iriggered by great earthquakes. One other landslide is located west of the Finn Hill area. Their e�astence demonstrates the ultimate instability of most steep slopes in this region. b. High rates of ma�vasting ia the larger ravines. Examples include the walls of the Lakeridge ravine, on Tributaries 0464D and E (in Bryn Mawr), and manv of the ravines in Finn Hill. Movement can occur far uphill, as in the two debris P:LWB 9 Lake Washina on Basin (Continued) slides at the edge of the ptateau above Tributary 03?8 that contributed to gullying and sedimentation dow-nstream. Mosi of the ravines should be considered sensitive, but those in which �oundwater eme oes at the surface are particularly susceptible to future landsiiding. c. Shallow slides, commonly soil wer tilt or bedrock, ocrur where very steep slopes have been formed by glacial or stream erosion. One example is the lakeshore bluffs and ravine of Tributary 0464A in Bryn Maw-r. In addition, manv such problems have been created by excavation. For e�campie, most of the steepest slopes in the Sheridan area are cuts made (in the 1S90s) for the Seattle, Lake Shore and Eastem Railway, now the Burice-Gilman Trail, where slides are common. Likewise, shallow sliding has occurred in roadruts along Juanita Drive (in Fnn Hill), I-405 (ia Hazeiwood), Rainier Avenue (in Bryn Maw-r), and Bothell Way (in Kenmore). Some of these may have destabilized uphilt areas as well. d. Hillside erosion from surfaoe water discharging oMer steep ban�s. This occurred in the Finn Hill area (e.g., Trib. 0224, RM .45 and Trib_ 0227, RM .60) and in Bryn I�tawr (e.g., Trib. 0464A, RM .60). There is a potential for similar problems to occur as areas on top of the bluffs over Lake Washington continue to develop. 2 'ILere is a threat of damage to property from tlooding in the basin. Flooding is being caused by: a Stt+eam erosion aad deposition transport Urban devetopment and its accompanying increases in impervious surfaces, alterations to stream channels (e.g_, the diversion of flow on Trib_ 0229A at Rbi .40), and inadequate erosion-control measures at new housing developments (e.g., on Trib. 0464D at RM .70) have caused the lawer reaches of many streams to fill with sediment. Sediroentation, in turn, has reduced the channels' capacity to carry flow (usuatly increased in volume and rate from upstream development). b. Undetsi��ed and failins culverts. The majority of the failing drain pipes found on reconnaissance were located in the Fnn Hill area near Lake Washina on. atong Juanita Drive. These have been in place for many years and may need to be replaced to assure that their sizes are adequate for cunent and future flows and that they are othen�ise properly functioning. 3_ Muc6 fish habitat 6as alnady bccn lost. Much of the historic habitat in this basin has been last or irreparably damaged by urbanization. In the Sheridan and Bryn biawr areas, for instance, most streams have been placed in rulverts. In the Hazetwood area, ihe sin�le perenniat stream has been piped beneath a park-and-ride lot and lost to fish use. On Tributary 0222 in Finn Hill, a 20 foot high dam near the mouth makes fish passage impc�ssible. Problems identified here (as well as the recommendations that follow) will relate only to those systems in which fisherv and habitat benefits mav be achieved with reasonable measures. a Barriers to fis6 migration. In urban systems. in genera[, Csh passage through � ruiverts and over weirs is a major problem. Numerous road crossinos and P:LWB 10 Lake Washington Basin (Continued) landxaping works pcoduce barriers of assorted kinds. Specific examples of barriers included: 1) Ihop barrie:s in the form of culverts, weirs and faUs occurred in the following locations: - a) Tributary 0233 (RM .45�, where a concrete spillway is a complete I�, barrier to upstream migration. b) Tributary 0464D (RM .?9� where a 3-foot drop from the culvert to the stream surface is a complete barrier. c) Tributary 0227 (RM _13� where an impoundment dam 20-feet high and �I 60-feet wide is a comp[ete barrier. d) Tributary 0056 (RM .OS), where condominium development has , landscaped the stream with pools and weirs but provided no fish I passa;e. , 2) Ftow barriers, formed by cuh+erts without baftles or with steep grades, have formed at the follawing locations: a) Tributary 0223 (RM .OS), where the culvert under Holmes Point Road lacks baffles for fish passage. b) Tributary 0056 (RM .10), where a box culvert under Bothell Way may be a veiocity barrier at high fiow. 4) Habitat 6as aL�o been d.amaged or destroyed berause of poor water quality, usually the result of direct entry of road runoff into stream systems. The worst cases of_poor water quality found were in ptaces where roads were constructed near stream corridors. This runoff contains greases, oils, oasoline, anti-freeze, and other road-related pollutants. Such problems were apparent in the Kenmore area where Tributarv 0056 receives direct runoff from 61st Avenue NE and in Bryn Mawr, which is completely urbanized. III. RECOIVII�iQ�iDATIONS FOR ACTION 'The following recommendations propose both regulatory and structural remedies for the extensive problems identi6ed and discussed in the previous section. Suggestions for interlocal cooperation are included, where appropriate. A Mitigate curreat damage from ma�-w�asting and other forms of erosioo and preveat further problems. 1. Adopt and implemeat ptanning aod cegulatory mea�s to protect seositive areas in the Lake Washina on Basin: a King Couoty shwild closely iegulate undeveloped areas within lands�ide haTard zones that are not already dedipted open space (parks, school property, etc.) P:LWB 11 Lake Washine on Basin (Continued) and designate them as open space. Priority should be given to the lakeshore slopes of the Fnn Hill area and the ravine of Tributary 0281 in Hazelwood. Vegetation removat shouid be minimized in ali such areas. b. Public agcncies should exemse sQecial care ia approving tbe sitin� desigq and oonstrucfion of structures wit6in and diracily abwe the laadslide-bazard zones. Permit applications in these areas should include professional evaluations of siope stabiIity conditions and potential for increase in erosion. c Maintain uplands that cvrrently act as natural �rater-sioragc areas (wet woodlands and pastures as weil az w�etlands) as open space, in order to preserve their stormflow-detention function. This applies partirularly to the plateau in the Finn Hill area and the uplands of Bryn Mawr. Both drain into channels with erosion problems caused at least partly by high flovvs. d Fsiabtis6 intedocal agreements among Ring County and the cities of Seattle, Renton, Bellevue, Lake Foresi Park aad other cities sharins basins in order to coordinate a future basin ptan and to institute a means by which the costs of future capital improvement projects may be shared_ 2 Miti�te and prev�ent problems using structural meastires: � Inctease R/D capacity on streams where nceded In some cases these can be integrated with wetlands. 1. In Fnn Hill, new or eapanded storage structures will probably be necessary for Tributaries 0�?2, 0228, and 0229A. ? In Huelwood, the recently rebuilt R/D structure abrne the damaged reach of Tributary 0231 may ameliorate the situation; however, this ravine is so sensitive that additional controls may be necessary. 3. In Bryn Mawr, increasing R/D capacity and lowering discharge rates could reduce erosion in Tributary 0464D. Some R/D facilities should be expanded and others fitted with control structures. King County should work with the ciry of Seattle on this project, as most of the tributary lies wi[hin city iimits. , b. Reroute sudaoc iunoff around seasitive reacbes, or tigfitline flaws throug:h them. This is partirulariy important in Bryn Mawr. On sieep slopes, tightlines should be roade of flexibte materials, or the couplin� on corregated metal pipes sealed, to prevent iealcage and failure. c Utilize inchannel eiosion oontrol structures for damaged sireams, particularly on Tributary 0281 (in Hazelwood) and 02?9A (in Finn Hill). In 0231, where access is easy, check-dams or gabion weirs miot►t slow the gullying, and reinforcement of the small bridge would prevent upstream migration of downcutting. Access is much more difficult in 0229A, but small-scale biceno neering measures could retard erosion in that channei as well as in other a llies in remote places. P:LWB 1? Lake Washinp on Basin (Continued) B. Miti�te destnu�tion to fish habitat and pneveat further damage- 1 Dev�ebp and implemcnt planning and regutatory measures to protect C�sh 6abita� a Fstablish appropriate interfocal agreements amoog public entities during the basin pianning process. Examples include Snohomish County, Lake Forest Park, Brier, and Bothell in the Kenmore area; ]uanita, Kiricland, and Botheli in the Finn - Hill area: and Betlewe and Renton in the Hazelwood area. Because of the potential effects to Lake Washington water quality, Metro should also be included in these discussions. b. Fstablish bilateral ag�eements betvveen King Caunty and Snohomish County and between King Connty and the rarious dtie� to develop consistent, comprehensive � guidelines and regulations for protection and enhancement of wetlands and stream systems throughout the basin. c. T6e King County Public WorJcs Deputmeat should give immediate coasideratioo to the devetopmeat of water quality standards and treatment shategi�s for urban stormwater runoff that enters Lake Washina on. d Devebp a at'rcen information and participation program to educate the public on how to become involved with water-resource issues. This is critical to nonpoint control in the Lake Washinb on Basin. e. Minimize and prevent lost of habitat features: 1) Establish greenbelts or obtain conservation easements for those criticai stream corridors and wetlands that remain in the basin. Of particular interest are the headwater areas of streams 02?� and 0�23. 2) Cooperate with the Washino on State Departments of Fsheries and Game to detect hydraulic code violations throughout the suburban area, particularly in the Fnn Hill area where homeowner landscaping causes the loss of quality habitat. 3) Consult with Washinb on State Departments of Fsheries and Game prior to designing rapital improvement projects in order to work out details prior to design. 2 Desi� and imp{ement structural sotudoas in order to restore and protect fish habitat in Lake Washington Basin � F�liminate drop barriers. Construct downstream weirs or pool-and-weir fish ladders as required. Barriers such as the la oe dam on Tributary 0227 should be carefully e�aluated prior to any removal or construction. (In this case, no action is recommended for the dam.) b. Eliminate flvw basiers. Install baffles at 10-foot intervals throuch culverts. Several types of structures are possible, e.o., siot weirs, angle weirs, and offset baffles. P:LWB 13 Lake Washinb on Basin (Continued} c Pieveat future batrier problems. Require that future pubiic and private rulvert installations follow these standards: I 1) Use bottomless arch or semi-elliptical pipes; � 2) Set culverts at mean grade for the reach; 3} Select sizes to accommodate the 100-year flood or fish passage, w•hichever is greater, 4) Set semi-elliptical (and round) pipes 1 foot belaw stream �ade; 5) Equip taiiwater devices with weirs to concentrate tow flows and not inhibit fish passage; 6) Equip culverts wer 40 feet long with baffles; 7} Avoid multipte-culvert installations. 3_ Improae water quality in t6e basin_ a. Enoourage use of twocell R/D ponds with forebay and gravel fdter. and discha�e flows through grass-lined swales. b. Iastall oil wrater separators to improve water quafity where necessary. P:LWB 1-1 k ; �- »��,.�.--�'"-e..��e--:.: � _ ' 4 LAKE WASH WGTON BASlN �� i� �� , - � ' �7. � � . ,� � f .:, G rti {North Section) ., -a . _- a• � , . ,;�i�� „�, 2 . `s,:M,.n-�-��.,.n.'�., - .....y _..,.._...Xu ,� � . '�� , ^. .�� _ � . .r� Basin Boundary ��:_. �_..�.>�.n.�`x''2,i .- '' ,. � . .� � ° , ` . `�" ' � ` —�� Subcatchment Boundary _ ,.x. . . , , , i� F i j � . :• . ,� � 1 - +:,�'s' z,� . o �2 Collection Point c t ; : '�. . '�; � �..e•�-�. Stream i r_�' �`N ...... . �� i�� ,: , } � �5�__ � '�'�� ;;�s Tributary Number "; �}�+�:s . : -, �t ,.. `�= •1604 Proposed Project � s, �i.__ ` %4 �• �;��_.� -t . �.. . ,� �;.,. __._ � t�' ; 4 *-��f }� 3 � ��'� �C .., �� : ;� ;! N : �. � ��t .�;.��:�� Q' �� '� � �� _ , �; '�� s • 0 t 2Miles �1J 5 :=�" �`4-_�.-. , s _ ��l � �� _: �i �� ;I ' . V'' ` � .a �"�i a � . f �� ,�`.' . . � .. 1 i ' a�.ti � �!� +� July, 1987 � 1 �� - '' 160 �� g � - _ �, 9 � f�;.. I `�'16 3 -- _ 12 1�. 3 '3, , 'z �_u, � .. . `t ,�' � , .._� % _ �``� � � � - - . ; , _/ �-- , � � .><. �:, � . � � - ��- '` _ �a�{� _, �t .,�3 F f: �� tE��ia 1 , '�t � .. ��`�'..�...1i�+...� ��p�'f L :1l f. �� . 1_T•4� ., 7� 4• . �} ��`'�.'• ..1 �4, � • .. . . �. . . `. '� � . . - .. � _ i �.-.a. i .. t � 1 .- . ,._ i {..., f ��":�.��"c .. � .:i� � . - - . . _ 3 'L. .+i'...-. . ... . . — - � .... _ �.-I `'� . . . - ... � _.. . ,�� r�: ',:.::� �. ¢a ' -�; . r i �< \ 7 , ; \�--✓—�� `- I � ` ,.r�{Aj?'� " y�r{� � �� ,y� •_� �,�-�. �- .�4 2�s �a J.+.�i�'�:`� E�. . I .: R�,l . � t� 1 J jy�s � . ��eC� �. Sd-". k 4.�y.. ' ��i � � " ". �"•-qhAJ,y�,��{ f '� � �� , . ... •�l�76t 't� -f �i `�" "} � ? ;,�-�. .�> � �. � } � i � . � � ��f t-�t� '' � t��£r . .�+�.'a� � ... ��a��'�1 `��5.�._ ��---- "§'R�� s'-a�'�—^"� � � f ' {s' : iz- � � ._ n� �'- _ z �j � ` R #T� t�� ; ��}�+ � �� ,�� ,_ 4 _ . } �;_� _ - _ ,� � �� } Y-. � . -, ��'' � . , _ .; - ,.. ."K '`' c., � ti'f £4 : '. : �.a ...- �r�- .. ' ' .,.. -'.. .`_ _lu.W �, � " v�n '. 4 �:.. y. .. . .., : � ; . . . .. .� • .;� . .� r� .. . . ' . y ._�. ...-_ ... .. �,. . . t _ :„ . .. F. - .,' . , �: • 'Lv ( . . .� ' } . . _.. _ _.r..':.'...�... ��\ A . . . �. j �� . .f� �' - ��_ .� °�. t �. � - . . �" � � . S.. � � ��' :s �a�x+�u �:�:g � f)gt*Iy.�.� dPF - � =_ : . �� '� _ '-h� �; Y � �'"`r� . . � c ._ �� E c �4,=�, '.' _ h` �u.z. __.� ' s.. . . !� � ��z f ;:. � _ =y �;.��; nz ,�. r~ti_. " �, :. ; - , ,''� j ,. , �� ; .: , . - � , _. _ 1 ="�- 4. r".�,- � _ _ ... f _ . ,�. '�. .... _ _ ::#. . : s . j . �"�: . - . ._ �_ , r#F �`�. ^ � . �t . � ' ! 3� � '� - . � �.� ' /"tf a��r-.-�'� - .; , •y �<"� '�; � , ' :� r ' s . � �t t�1�,t:s,a^,av.M�..�,-�k<-.�x _ �a" ; �� .. . � 'r 'f \ _.� } �i «1 .�k '. . . � _ . - . .i. I �'�..�. l 4.5v � �+ e�; ,1 } . ��"„� � .' . � � �£ t4 '^�' ��. ; Y� . _i . x . . . . �'-�- -��. � --�� _ . . �- .. :t � ` � ; �,� � `t `�� a.�, --��. � . gi �` _-. ,;. .. . ._ � - • ' �� , ~ � - >, • f , _. . , . . • . �� ...�� s� S Ai �.`�°• '\ .� r � ;� .�� ,' ` � � ; - ^ g � . trf� i r�l h�y��"�.,. �( . .. . ' . � f x�� .. .. 'k x.< � \ t� _ . . - °1„� - �.l'"� i . . - � . . ��. � � ,i � � ' �� . ` � ' - . ' � � lt f '.. _ 4 j� � f : .._. . . . t�_�. �' . �l - .. . , ' . .. � i . � �I t. rf f`�^ ! � II� LAKE WASHINGTON BASIN � ' � �� (South Sectionf \. '�, �`�` i" <� 4r+� Basin Boundary ` r„ �,��,i l �"'� Subcatchment Boundary ~� �°-`.> - �i �2 Collection Point �'� � . _ I ...- - Stream '�t,. 3� I �3 i:: Tributary Number - ` ' �6404 ° " ',� �� Proposed Project ; � � � � �' �` �� ; I� � s � 3`y �j ��` t g �. .' � �ti � N _ 6 p �a �� ir� ( � �O ,-; � � .,. D �rt Q � � � . . f' Zi� y �F . '`� � _ ct� July,1987 - �"� �" ` �� \a � . _ � '�y _ „ . � —�(.'-�£ :'_ ../-, � ' $ i ;r': ' .•' f .- tf _ ' llill ��. ' O 1 2 Miles _ �� `:� % ' . � � � � _ ; s x �m ,� ._ . _. ,y� _._.� ��. . . . - �� • •� � . . . . � . . "�a'.•,Sk.x' <°F:- � . . - �- . . . _. . �� ¢ _ . APPCNDIX A GST[MATCD COSTS: PROPOSED CAAITA[. IMPROVCMCNT PROJCCI'S LAKC WAS!-I[NGTON BASIN " Indicatea projeat was identified by the Su�fece Water Management Division prior to reconnaissance. NOTE: All projects are located on map included in this repo►1. I'rojcct Collcct. Cstimatcd Costs Numher Point Project Description Prohlem Addre�,sed And Comments 6402 4 Construct o proportional weir in the Increases detention o[ wetland located 5129,000 cro.ss culvert at Renton Ave. Wetland upstream of Renton Ave. will reduce (Project should be ana- has not been inventoried or r�ted. peak [lows downstream. lyzed at time of basin Will rcquire further study And an�lysis. planning.) G403 S Replace failed sec�ions of existing cross Project will stabilize eroding road embank- $54,000 culvert and stabilize failing roAd mcnt and reduce sediment to creck. embankment. Project is independently juslifiaUle. G404 8 lnst�ll standard control structure in Project will increase detention to Trib. $41,000 cross culvert at 85th �nd [3owling St. 0464F. (Depends on land i Ucpression on upstrc�m sidc is ideal for acquisition costs. dctcnlion. Project should be ana- lyzed at time of bas'in planning.) G405 11 Improve drainage system at 132nd and 80th Flooding and ponding of watcr in intcrsec- $68,OQ0 Avc. S. tion. (Project is inde�en- dently justifiable.) x t�:i..wr�.ni�n . �.1 Project Collcct. Estimatcd Costs Numhcr Point Project Description Prohlem Addressed �nd Comments 1G02' 10 Inst�ll a stand�rd control s►ructure �t Will mitigate high peak flows discharging 5136,000 Wctl�nJ the outlet to Wetl�nd 1602 (rated #2) to to Trib. 0228. (Depends on land 1G02 increasc dctcntion. This wctland will acquisition costs. require furtl�er biological evaluation Project should be before It/D design and construction. analyced at time of basin planning,) l(03 12,13 Install piping system necessary to direct Streaml�ed erosion in Trib. 0229A located $252,000 flows (which had been piped from sub- in subcatchment 13. (Project is indepen- caichment 12 to 13) back inlo collection dently justifiable.) pt. 12. 1fiO4 10 Repince existing undersized cross Flooding on upstream side of culvert, which �25,000 culvert at Juanita Drive. will worsen as development in area con- (Project is indepen- tinucs. dcntly justifiablc.) 1605 5 Install 400' of tightline. Ilillside erosion and high sedimcnt load in $75,000 ! Trib. 0224. (Project is indcpcn- dcnUy justifiablc,) I':I.WI3.i11'�1 n.2 APPENDIX B CAPITAL IMPROVEMENT PROJEC'T RANKING LAKE WASHINGTON BASIN (West Lake Washington Projects) Prior to the Lake Washina on Basin field reconnaissance, one project had been identified for the West Lake Washinp on portion of the basin and rated using the CIP setection criteria developed by - the Surface Water Management (SWM) and Natural Resources and Parks Divisions. Following the reconnaissance, four projects remain propcued for the West Lake Washington portion of the basin. They include four new, previously unidentified and unrated projects. These displace the previousiv setected project, which w-as eliminated based on the consensus of the reconnaissance team. The previous SWM capital improvement project iist for the West Lake WashinD on portion of the Lake Washington Basin had an estimated cost of S300,000. The revised list increases that cost to an estimated $301,000. The following table summarizes the scores and eosts for the CIPs proposed for the basin. These projects were rated according to previousiy established SWM Pro�am 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. These projects can be considered now for me bing into the-"live' CIP fist. RANK PROJECT NO. RATING COST 1 6405 75 $ '72,000 2 6403 60 56,000 3 6402 44 131,000 �1 6404 32 42000 TOTAL S 301,000 P:LWB.APB B-1 APPENDIX B CAPITAL IMPROVEMENT PROJECT RANKING LAKE WASHINGTON BASIN � (East Lake Washington Projects) Prior to the Lake Washington Basin fieid reconnaissance, one project had been identified in the _ Fast Lake Washinb on portion of the basin and rated using the CIP selection criteria developed by the Surface Water Management (SWM) and Natural Resources and Parics Divisions. Foilawing the reocnnaissance, four projects remain proposed for this area. They include three new, previously unidentified and unrated projects. These do not displace the previously selected project, which remains on the final list. The previous SWI�t capital improvement project list for the East Lake Washington portion of the Lake Washino on Basin had an estimated cost of 5200,000, while the revised list increases to an estimated 3504,000. This 152 percent increase in estimated capital costs is due mainly to ihe addition of new projects. The following table summarizes the scores and costs for the CIPs proposed for the basin. These projects were rated according to previousiy 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 ansv►�ered affirmatively. These projects can be considered now for merging into the "live" CIP list. RANK PRO]ECT NO. RATING COST 1 1603 55 S 263,000 2 1605 40 79,000 3 1604 30 25,000 4 1602' 23 137.000 TOTAL 5 504,000 ' Project identified by the Surface Water Management Division prior to reconnaissance. P:LWB.APB B-? APPL,NDIX C UL"1'AI(,L•U �INUINGS nNU RCiCC)MML'•NUA'I'fUNS LnKC WASIIINGTON I3nSIN " All ilems Ilsted here are located on tinal display maps in Ihe ollices of Surlace Waler Management, Building and LanO Development, and Basin Planning. '1'rih. �C ('ollect. Existing Mticipalcd Itcm' Kivcr Mile 1'oint C��te oi I'rop. Proj. Con�ii�ions �nd Problems Conditions and Problems Rccommendations 1 f)05(> L'1 Ilahit�t Condominium development h�s Same as existing conditions. Require development to proviJe fish RM .05 I�ndsc�ped stre�m but pro- p�is.�.��e facilities. vidcd no fish p�s.s�i�e through ponds. 2 00.5�> L1 Il�Uitat Box culvert under I3othell Same �s existing conditions. Construct fish-p�s.s��ge facility At 1tM .1Q W�y is a drop b�rrier to downstre�m end of box culvert. upstre�m migr�nts. 3 005(, Cl Il�ihit�t Stre�m reccives ro�d n�n- As upstrenm development in- Isolate storm drnins from creeks, if , RM .50 off from numcrous catch- cre�ses, w�ter quality possiblc. Use vcgctnted swnles �nd b�sins. problems will become morc two-cell R/D ponds to filter runoff. severe. 4 OOSh L1 IIn1�ilat Creek h�s been forced into S�me �s existing conditions. Add hnbit�t structures to channel, ItM .30 rondside ditch with ro�d- rcveget�ite hanks to provide pro- w�y constniction. Ii�bit�t tcctivc scrcen. divcrsity lost. Fish use declining. S 005�> C2 Ilabit�t WeU�nJ fills occurring in T.o�.s of wctlands will reduce GStablish � cooperntive b�sin Ilc�idwatcrs hcadw�ter �reas o[ slream pro�fuctivity and pl�nning ngreemenl with Snohomish Snoliomish County (city of summcr flows, incre�sing County nnd city of [3rier for Bricr). pc�ks nnd volumcs of winter protcction of weUnnds nnd strc�ims. flows to King Counly. I':I.W13.n1'(' C.l 'I'rih. & Coll�ct. Existing Anticipatcd (Icm Rivcr Mile Poinl Ca�e�ory Prop. Proj. Conditions and Prohlems ConJitions and Prohlems Recommendations h 0222 C3 Ilubitat Stream h�s been piped under Same as existing conditions. - Construc� opcn channcl with h:�bit�it ItM .10 f�rinvay for approximately enhanc�m�nt through faitway. 750'. llistoric fish usc - Itemove; pipe and direct stream in�o through this reach; ncw channcl. habitat lost. 7 0222 C3 Geology Channel erosion in Ingle- Stream is channelized through - Maintain the upstream wetlonds (above IZM .2U-.GO wood'golf course, along most of this reach, and the RM .70) to butfer high flows. Juanita Ur., and in vacant channel m�y he too sm�ll to - Assure that the R/D pond �t S. end lot upstream of Juanita accommodate present (and of golf coursc cAn accommaiate high Ur. Dcposition in pond anticip�tcd future) high flows from the upper b�sin and servc on the golf course. Some flows, Continued construction ps a sedimcnt trap. sedimcnt may have come upstream will prob�bly in- - Rebuild chann�l upstr�am of Ju�nita from recent construction creas� high flows ond act Ur. (RM 0.6) to stop erosion there. along Juanita Dr south as sediment source in the of the golf course and future. developing area to the east. 8 0222 E3 1labitat Gol[ course pond used as S�me as existing conditions. Fstablish minimum flow requiremen►s RM .30 water supply for fainvays. to prevent dewatering. Lower reaches of Trib. 0222 occ�sionally dewAtered. M�y incre�s�; rearing morlality in wetland. , �) 0232 E3 Ilabit�t Trit�utary flows in storm S��me as existing conditions. - Seal catchbasins to prevent road RM 1.00 drain. Runoff from short runoff entry to streum. Action portion of Ju�nita Urive affects only 2-3 catch bt�sins in cnters 2•:i catchl�asins a one-block distancc. �nd (lows dirccUy into - Uirect n�noff into parallel tight- strcam. linc: sy:stem that byp�sscs stre�m. I',I.WB.nPC G2 -_ --- _ Tril�. & Collcct. Cxisting Anticipaled Item River Mile Point Catc�orv Prop. Proj. (:onditions and Prohlems Conditions �nd Prohlems Recommcndations ]0 0222 C3 Il��bitat Ilistoric encro�chment on Loss of wctlands may occur in Prescrve these headwater arc�s from Ilcadw�tcrs wctland. Some fill contin- this hcadwater area. encroaching dcvelopmcnt. Rcmovc uing on perimcter. Portion fill; enhancc � portion for emcrgent of wetland is bog. marsh hahitat. Problem was referr�d to Building nnd Land Uevelopment for action. 11 0224 I:5 Geology Gullying of ravin� slopes There will be some increase - Repair tightline. RM .]0-.50 below street ends (Glst in Clows as construction - Route drainage on north side along PI. NE and 62nd Ave, NC), proceeds on the pl�teau. bench above thc stream (cotinty road culvert out[all (RM 0.45), Main problem, though, is poor and sewer right-of-way) to th� west, and broken tightline design and/or failure of or tightline to the strcAm in � (RM 0.35). Sandy slopes drAinage structures. s��fe, nonerosive m�nner. �re natur�lly scnsitive - 1'ightline culvert at RM .45, to ch�nnel erosion and sliding. Sedimentation in R/D pond at valley mouth. 12 0224 LS Ilydrolo�y Privatcly owned instream No future problcros antici- None. RM .10 sediment pond exists at pated. this river mile. Pond was found to be nearly filled with sediment. This sediment �ccumulation appe�rs to be a natural proccss �nd not a result of increased peuk flows from upstre�m developments. 13 0224 C?5 Ilydrology 1605 Sevcre hillside erosion Continued hillside erosion Ti�htline drainage to bottom of hill RM .4S & Gcolo�y caused by surfnce runoff until mitigating measures and provide adcyuate energy dissipa- from NC 154th St. dis- are taken. tion. ch�rging at the top of a steep slope. P:i.WI3.APC ('-3 "1'rih. & Collc�t. Cxisling Anticipated I�um ltivur Milc Point C�ilc o� I'rop. I'rol• Condi�ions and Prohlcros Conditions �nd Problems Rccommena�i�ions 14 0224 CS Ilydrolo�,ry Ncw devclopment is dis- Area dr�ining to these tribu- None. ItM .35 charging storm ninoff nt tt�ries is ncarly fully devel- this river mile. Tight- oped. It appe�rs that �de- lines were ��sed to route c��iate detention and convey- flow down erosive hill- ance systems discharging to slopes. these tribut�ries were in- , stalled and arc functioning. 15 0227 L7 Il�bit��t Impoundment dam. Impass- Same as existing conditions. Nonc. ItM .18 Able barricr. 20' high x 60' wide. I<, 0227 C7 IlyJrology Old w�ter supply dam (20' Reservoir will continue to None. IZM .18 high x 60' wide) at this fill up with scdiment. river mile. Dam is no long�r used for water supply; it is acting as a sedimcnt trap and is pttenuating high flows. 17 0227 E7 Ilydrology Old water tank is discharg- Flow from tank could be None. RM .20 ing ro creek at this river helpful in maintaining flows mile. Flow rate is ap- during low-[low months. proximately �/ of total flow in creek. 18 Q227A C7 IIydrology Drain�ge system inst�lled Continued flooding �nd Problem referred to DrAin�ge 1tM .13 in new developmcnt is crosion of NC 135th PI. Investigation Section of Surface not adcquatc to I�andlc Water Mnn�gcmcnt. flows. 1':I_WL3.nPC C-4 7'rib. �C Coliect. Existing Anticipated Ilem Rivcr Mile Point Catc�ory Prop. Proj. Conditions �nd Prohlems Condi�ions and Prohlcros Rccomm�nd�tions l9 0227A L7 Geology Some channel erosion along Probnbly due to n,noff from Control disch�rge of runoff from edge ItM .2.5-.40 small tributary channels. homes along edge of plateau, of plateau, es�cci�lly [rom any Some deposition abovc new Soils and slopes are very future sourc�s. May be necessary to housing development. scnsitive to erosion, Could tightline some of the existin� hccome a major problem for sources on the steepest slopes to the the downhill develo�ment, bottom of hill in � safe, nonerosivc cspccially since it is manncr. located at the Cocus of a the�ter-sh�ped valley. 20 0227[3 L7 tlydrology Tightline has separated, Slopes will continue to be Repair tightline in such a way that ItM .00-.25 & Geology allowing water to eraie severely eroded until the segments of culvert can't become steep hillslope and cause pipe is fixed. This problem separAted, or replace line with gullying in small tribu- may be the major source of flexible pipe. (I'roblem referred to tary channel. Deposition sedimcnt filling the pond on King County Drainagc Investigation in Trib. 0227 at [Iolmes 'I'rib. 0227. �nd Roads M��intcnance sections.) 1't. Dr. (Problcm wns first identified in 1986.) 21 0228 E9 Ilabit�t Concrete culvert under No ch�inge, S�me as existing Inst�ll baffles in culvert. L3ack- ItM .OS I�Iolmes Pt. Dr. is a partial conditions. flood to eliminate drop. � migralion barrier due to velocity and outfall drop. ! I':LWI3.nPC GS 7'rih. & Colicct. Existing Anticip�ted Itcm I2ivcr Milc I'oint Catc o Prop, Proj. Conditions �n�i Problems Conditions and Prohlcros Rccommcnd�itions 22 0223 L9 1laUitat Good habitat for resident Same As existing -conditions Control stormwatcr flows from future 1tM .30 and anadromous [ish. unless flows increase. '!'hen upstreAm dcvelopments such that vol- Uecp pools and extensive expect incr��sed erosion and umes do not increase. 'I'his will riffles. Slight deposition se�iiment deposition leading rcyuire higher than normal R/D in pools at obstructions. to decreased habitat diver- storage und rvlease rates below bed sity. scour limits. 'I'his area should be , �ddcd to the SAMF. 2:i 0323 E9 I(abitat Cascade to 6' high. Im- Same as existing conditions. Place steep-pass fish-way here tempor- RM .45 passable barrier. �rily, then construct perm�nent pool-weir fish IaJder to allow salmonids upstre�im passage. 24 Q224 L9 Geology Two small landslides nt No direct sources of surface - Assure that no surface runoff is I2M ,50 edge of plateau; severe runoff were found, so it reaching the la�dslides (it may be gullyi�g from slides appears that wAter source necessary ta tightline flow from downstream to the creek; is seepage. Crodiblc streets and homes directly to th� deposition above driveway materials in steep slopes creek). bridge. Most damage will continue to be eroded - Revegetate slide scars to inhibit probably occurred during (dry ravel, spring sapping); erosion. Jan. '$b storm. gully walls are continuing - Consi�ier installation of check-dams to fall in. in the gulty. 25 022R C]0 (;eology A hreached dirt ro�d-fill The creek will continue to If the road bcd is to be abandonc�, RM 1J5 is being erodcd Uy the undercut thc sides of the reduce slope of faces :�long �he stream; raw slopcs con- fill. stream (or fix site for use as an R/U tributing sediment. facility). 2<, 0224 L10 Ilydrology 1G04 C�isting cro�.s-culvert at Increased frequency and Rcplace culvcrt with a higher-capa- RM 1.22 Juanita Dr. is undersizcd. �real extent of flooding city pipc. Water has recently ponded on upstream end of culvert. to a depth of 6' on the upstrcam side. I';I.W13.nPC C-h 7'rib. & Collcct. Cxisting Anticip�tcd Itcm Rivcr Milc Point (:atc o� I'rop. Proj_ Conditions and ProUlcros Conditions and Problems Rccommcndations 27 0228 C10 llydrolobry lGQ2 Project proposcd by County Pl�teau area is developing. An�lyze projcct at time of basin ItM 1.45 Surface Water M��nagcment 'I'his location is excellent planning to determine if project is to acquire wetland and for �ddre�.sing inereased nece.ssAry. Conduct thorough biologi- construct control structure peak flows. cal �nalysis to determine effects at to incrcasc storage that timc. capacity. 2� 02�8 C11 liydrology Road emb�nkment is eroding Continued emb�nkment erosion install ripr�p on eroding area, RM 1,55 into TriU. 0228 at this of NE 13$th St. Problem raferred to King County roAd location. Most of shoulder maintenance section of Publie Works. has been lost. 29 0223 CI1 }Iydrology Storm-drainage infiltration Continued floaiing and sub- Install underground vault in place of RM 2.40 field is failing due to basin erosion until mitigat• drain field and discharge to nearby impervious soils. This is ing measures are taken. drainage swAle. Problem referred to c�using frequent flooding Dr�inage Investigation SCction of and failure of ro�d sub- Surface Water Management. base of 149th I'I. 30 0229A C13 Geology Channel downcutting, bank- Reccnt roadside ditching - [ncrease R/U facilities north of NC RM .00- and lower-slope erosion; h�is expanded the drainagc 120th St. ' .GO dcposition at the mouth, �rca, so downstreAm problems - Considcr inchannel chcck d�ms in L.�ndsliding on ravinc may increase. Impervious middlc reach (state property). slopes. surf�ce area may incre�se - Consider redirecting flow from are� greatly upstream, causing west of 76th PI. NE back to thc accelerating erosion in the southwesl (tightline along NE 115th ravine. St. and through small ravine). P:L.WU.AI'C C-7 , , . , -_ �--. i II 'f'rih. �F Colicct. Existing Anticipated I Itcm Rivcr Milc Poin� Catefiory Prop. Proj. Condiiions and Problems Conditions �nd Problems Recommendations 31 OO��) L13 Elydrology 1G03 Increased flows to Trib. Erosion will continue as - Redirect flow from collection point RM .00-.30 & itabitAt 0229A have causcd sevcre d�velopment in collection 12 away from 1'rib. 0229A. Pip� flow I erosion in this r�ach. point 12 continues. directly to I�ake Washington. Approximately 75 �cres of • Provide gre�ter R/D volume �bove I drainage arca from col- Juanita Drive, along 76th PI. NC � lection point 12 has been and from cnd of NG 113th St. I divert,ed to this tributary. � 33 02?9A C13 llahitat Ro�d ninofF from numerous S�me �s existing conditions. Provide catchbasins with oil/water I RM .30 catch h�sins along 76th separ�tors to decreAse pollutant load , Ave. NC enters creek. to ste�m. i Likcly ncg�tive cffects on water quality. Down- strcam residcnts noticc turbidity, oil in strcam aftcr storms, 33 0229A E1:� Ilabitat Runoff from Juanita Drive Same as existing conditions. Fit catchbasin at last discharge point ItM ,75 and adjacent parking lots with oil/water separator. is directed into stream here. 1'urbidity, oil film �re apparent �fter rnin. 34 0281 C16 llydrology 1..��kehurst regional deten- Pond appe�rs to be function- None. ItM .2S tion and sedimentation ing norm�lly. pond, construction com- plete. I.arge amounts of sedimcnt have been aeposited in pond. P:1_.W[3.APC C-8 i I "1'rih. & Collc�t. Existing M�icipatcd Itcm Rivcr Milc Point Cale o� ProP• �'roj. Con�i�ions and Prohlems Condi�ions an�1 Prohlems Rec�mmendations 35 03R1 Llfi Geology Active, m�ijor downcutti�g Crosion seems to Ue a re- -Assure proper funetioning of RM .3Q-.gS & II drolo in the ravine (RM .40-.(�S), sponsc lo incrense in hi h u stre�m R/D facilities , Y s� s p undcrcutting lower slopcs; flows caused by dcvclopment (cspccially �t SL 60th St.). I bank c►•osion upstream upstrcam. l�urther increases -Require onsite IZ/D if/when the two (RM .4S.,R5), Vall�y is in impervious surfares up- lar�e p�rcels �long llhth Ave. SC cul into eraiible s��nds stream could aggravate are dc;velopcd. Any runoff from and �r�vcls. Ch�nnel erosion. 7'wo lt/U f�cilities homcs in Lake Ileights (east of erosion is undcrculting upstre�m �t SC hOth St. m�y vallcy) should be routed around to hillslopes in placcs. have already improved Ihe the north; prohibit uncontrolled Fle�vy deposition in R/D situ�ition but the sands and disch�rge onto hillslopes. pond (RM .40); dcposition gravels arc vcry susccptible -In the ravinc, rcinforce the small �Iso �round docks at mouth. lo erosion, bridge (RM .GS) so th��t aown�utting Problem may be affected can migratc no further upstrc�m. by presence of sewer line Consider install�tion of check dams in ravine. or guhion weirs in gully. Maint�in natural vegetation in the corridor. 3G 0?S1 C17 Ilydrology Cxisting R/D facility is No change. None. ItM 1.14 detaining water nearly to capncity. Providing good detention for tributary. 40 04C>4D W6 llydrology I��rge quantities of sedi- Problem will continue until Problcm referred to dr�inage ItM .00 ment accumulating in lower groundcover is reestablished, invesligation section of Surface re�chcs, Ncw construction Watcr Managemcnt. upstrc�m not controlling erosion into creek. P:I.WI3.�1PC Gq Trih. 8c Collect. Prob.Site/ Existing An�icipatcd I�cm Rivcr Milc Point Cate�orv Prop. Prol. Conditions and Prohlems Con�ii�ions and Prohlems Recommendaiions 38 04C�4U W3,5 Geology Streambank erosion an� Prohlcros will continue and in Maintain the large weUands west of RM .00-I.Q7 landsliding in stcep-wallcd some cascs incrc�se. Slight Renton Ave. (04h4L, RM. 20) anJ south ravinc. Cl�anncl erosion, incrc�sc in impervious-sur- of S 1151h SI. (U4G4D, IZM. 96). especi<�Ily bclow culvert f�icc areas upstre�m (especi- Sediment tr�p at RM. l5 would help (�t RM. 9G), through brcach- �Ily in subca�chments 4 and control deposition �t Ihe mouth. ed roadfill (at RM. 78), 5) will incrc�se pe�k I3e extremely careful with runoff from and �long sewer. flows. The steep slopes homes �long the ravine edge; route it will continue Io fail, con- around steep sections or tightline iributing sediment to the to the bottom of the stream. strc�m. Ilomes are built (pr are being built) all along the cdges of tl�e ravine; some may be damaged by [uture landsliacs. 39 4(i4U W3 II�►bitat Sediment�tion at culvert Same; �s existing con�iitions. Dredge scdiment from strcam. Rcplacu RM .25 inlet trash rack has cause;d existing tr�sh rack and culvert inlet complcte migration barrier. to providc fish pnssugc. 40 Q4h4D W3 Ilabitat 3' drop from culvert out- Same �s existing conditions. Repl�ce existing culvert with 42" I RM .29 fall to water level; com• semi•elliptieal pip� se;t at aver�ge plele upstream migr�tion re�ch grndient, botlom at 1.0' bclow bt�rrier. bed level. 41 04�i4n W11 Ilydrology G40S Dr�inage system at intcr• Continucd flooding and ro�d- Install new system of catchbasins �nJ ItM .60 scction of 132nd �nd 80th bed f�ilures, as high ditch drainage pipe. Ave. S i5 not adequate. flows h�ve bcen eroding I�loocfing of the in�ersea the subbase. lion occurs rcgularly, �ccording ro rc;si�ients. I':I.WLi.AP(; GIO 7'rih. & Collcct. Cxisting Anticip�ted Iicm Itivcr Milc Point G�tc o Prop. Proj. Con�ii�ions ��nd Problcros Con�i�ions �ind Problcros Recommcnd.�lions 43 04h4U WS (lydrology 6403 I3ottom 8' scction of cul- Roadhed erosion will continuc Replace bottom section of pipe, ItM .9G vrrt crossing S 115th St. until miti�ating mcasures install gabions to stabilize failing has failed, causing road- an employcd, bank, and remove d�bris from upstream bed erosion. Upstream end end. is blockeJ with debris, causing water to pond to a depth of 4-6'. 43 04(�4C WS Iiydrology 6402 A sm�ll wetland cxists on All of the flows generated by Acquire wetland and construct A 1tM .')G the upstr�am side of Renton subcatchment 4 could be control structure in the culvert Ave., prob.�bly a result det�ined by a deten�ion crossing Rcnton Ave. of �hc high fill hcrm used pond �t this loc�tion. for the road. • 44 -- W8,9 Cieology Runoff from ronds, street Gullying will continue as Route flows (especially from culvert (I�illsidcs) ends, etc., is eraiing in- long �s flows are routed NE of Dimmit Jr. II.S.) around the to the hillside along onto the slope. Sediment area, or tightline to bottom of hill. several pathways, mostly m�y affect homes downhill. within King County park land. 45 Q464� W8 Ilydrology 6304 Small depression loc:ated L.oc�tion is ide�l for Install st�ndard control strueture; on ' RM 1.32 nt corn�r of 85th Ave S detention. With suitahle on upstrerim side of cross-culvert and Rowling St. control structure, detention to detuin flows in depression. c�n protcct downstream rcaches. P:I.W13.n1'C; C-11 � - 6.2 GEOTECHNICAL ENGINEERING STUDY � BY EARTH CONSULTANTS INC. DATED MAY 2, 2002 .. � �n��kiv"�c.;� . ,�,� P.... _ . i a.�iji\,.�� ` {'' .S,'�s 4 MC� ' ,. � ! '� �':7i �� "Y ��``ei�F � zJ �. ��a $ r� ., a an� �ti. �� '��"y��d . ,�k "Y k p�m�+��}`Y��. `��`�MN� f� �' . !�K_, ,�t �k ` y .� r !��d•�� Q % � ` ��' . �� . � � l�Ylv')�i ,, : S � t, � . . r"� �j � �, � � ��t y, ' , f� .. � u T �. 4 v �?G ,1 � ,� .. � vEF�syJ��r�� l„4 [+'i+ `� �y�1t�^`'�'�,2�Lw � �.� P��a o . . �.1,r �, � �' ,, �"�'�y� 'c �, � ��'s�°�yd v` = r��.'` X ': � 9 . � . +� � .�, � 'a � ,�� `aa�fy . � �ci�r t t .1�,,vu � �C .. ��. . . v,y� ,.y ' !� �> k� ��.�b',< 1 �nx,� a r+, t�� "�'a �:�t y� , . � -�*�* S � � �`� 5 ��ry��'"{u Y . ;� '14.�, � . .:.� � . � �� .�1�� 4 �.`'' 1 v� ,,.., fl��wt � , � ,: � ' v�`�tt�"a t a � �� { . YM� . .. ., � � „ ....JY� .. �� . � . � ��c ��`�4'��'�%�'^`"f �44�, i 4. . � �.. �R}f :� i�� ` � � /�� '� � ,. d�+.r.C.�,�orr.�;!.a��`CkSa��.��.�,n.,.... , ,� . F�� 5 !t �,�� . 4.� 1f �•f '�+'p��`;:, ��^j �� ' � � � . t� ° �� '� x � �hQf ,^�^ .�Y . . � �rWl r �` � � �� - z a � � � �,�_ �r, Q W Q �` � �,s a s� �w, _ � � � W „ ' � � O �._. '��r �� • � �.� U' � � �; ��. E;. J Z v � < �� , � ' � W Z � i�,r', �,�.�6` ��I a ,�"�' �'' 'v� t e:t,y . :.. �. � ..��, . W p Z N �; Fr�� ,Y�' � �� ,�� ,�? 5 � �.1" �Y'.r� �� ,� 1 Z � � Z � O �� ,,� ' • � �� <>+ "� ` , ' , � i� a �y,� p� _ G Q y � N � � � �� r<K�� .��'��.��a��,��'��°� r ,7 � � 4' ^� <� z , � � s�: /� d�, p,.. m \ ,�J a t Yr y�; a � F� f 1„� �./ �- � r �F r "''M t � �'� ''9` � klf`H"`� � i �� yi): �La��'�Y��A`� fi�'�'� t� ��, i a� M?,� �°�' �frT � Q • a �� '.�e, � � . „�?�R�+,�:�' . .. K.. . �ti>}t �.�'�t +��ih,t yg�k.`�Qlaa� RB'�.�'k�a rfk.�„�u .,r ,?. � r ,. . .. 11� .r�� r( Z Z N �,. �. . ,.. d �� . � ,;. ,�: J Q � � W � � .�� 4 Yrm��ua�M^v�� :. ��,*�'r�'.. � � �, �" .r a�u`;��i,+N,�`'��a �� e� g� a. � ra� � �4v � aVd�ti V � m O � K �� .,� ` � ��a�a�r � '��,��w � � �,,, �.. � ��.w :�,� a �;,��y as � ,°:�,��a �� y'v �" �' � A �h.°� �'� i t'�Ji!u%��' '�� '''�18� 1. M' �� i.i\ �'ti d`J r� W �� tl IX r MYi A+l '� ''� � �' �'' 1 .�J . �,W�,�'�4�4 \��y}ti�.x'�'.`,y�r't � -� •. � i �n �. re�v �� ,'a'��,��Pf�'� . U O Z � �. �a" � � t �+,�° �W� , r '�A� ,3 ': �. "t�}n n y�,r A d �r r�s�. � �„� = 4 ,��h'� a�, tr , „q�� : � �� t,��,'�i,�wy�x��;��t�fwuH�. P � W � ' .' 4� '�", � � wt�n� � �t�A��'14,�d� q.�4�t �: � .J : .. . t �yy�� e � ia t�'ra"'�Y�GY 4t �,,5 n.�: xt �'�.� e^"v 1wU �5 � x7f�� Q. � ` � ' 1 e m t . r Q /'' �^1 `�� Ft, � � , W � u �, ,�, � � �„ � � � s a ,� ,�g, � "'�^� . _> +� r�� k� a�'�' �� 0�� '�, �Y ��6"d� . r t� {'��. �'�.�'��a�C�d,�*t� . r 7 � '��?,^a��' �� '+ ° rt �(rM F 1 ��'+�"7i.�.�� YY�^'' ,� � . .. �'ti Y�� ,s�U,,,�'"'yp"�M��. .ti, �� ;�� I ��,�' �� y� �`��: ��. `� �° k tl . .... ..... . � l . . .. . .�� . . . . � . ..,., ��;k � � �� y �� t�.\ � 9�� . . . pt� . h .�r � S f r ,� �� .i � + . �. : ��7 @ �r 1 �� f � � . �i� dt�.5 `.,,�y� d ��i� p o-:,r`� v .Vt a'cr.��1 Jk,�. L e ��.i � t Ko.�:. ,'�� x¢�'., � m � h 1��. sx > c � � 'j� +� �� d n �"� �* tl .� it . . '� � �i$ " .� r. �{S��y..t.�`"ri'��,a�'1�vS�`f \.:��.��`� �,�xG��,�t��l�,;,s.�o3}' t:'.; a •- �it � � . t �•� . `�,�t�'� w.ny2�rM�f :,v,�., t �� ` ,a !�':: �� ::�M4a$FN`�^�l��n" �ph..�'r..Ft r"a� w ; ', "d 1�t w."' ,a,a��y"�+kk y',,N� d `4�, LY. r�� ,q ��"•.. ay.. ,Y:r t �� 1 N4a �'i � 1, 1; y � � ��'"�sm...�n a,�� i:�t=�' �, t Z,. �' `i 1a �v� t��^t C i�"- !Yt.°�� .�"°'k.w�,�+�� L '�� , p �¢.�}t ��#ar,o'�F^�r�,�"yr.,;au,c, + k�, �"�' v'�`,,�i,,,,;�`� T� �4S `��fi' �,� � ��y ;a� p � .,z r1 � R ,� 1,,��.�:r�w1�r.1'1'.��4M P .. ,��, ��v r �a"P��. �'�, ,�:�a� �.<.�p,� �1 it Kp �� " a Z }, �`��-��ee,,S;X hW'8p� W iM y �' . t .�^:;r`4„ ,� {,�t�'�n'F'�° h"p" a 7', .,;'i � ��.h M j ��,` �:t`�i,p.,,� � ��dt,�� a.t�'p.,��k v�.�. �. ?,� k�1 ,z,��f i r }+w..; �M��, s� .:rs� a �.5 �� ' t ' �{ �� V o� , a�(i'd {4�tY*"yy,i, � � ..;.�.i6 �i�;�.; ';e�,l�°�.� t� ��,�r�4 � � ��a�h� g a"�`tM1 Wt,�' a "hy�3,'�.a '�� t � ;,y;�N�.it�'i. .i"�: m,4y'r�C��.is'��.,. .� .t.:,.r K . >� `�• �q W`� '\�!: �i�� 'r� ��:� � �i t ��v;��`+� Y. ( FwE zk� ��,�' wu ��- ,�� ^� .��,�i^. � . � a,�.� .. . 4 a �V'�'��a1�fi�°�',.k. �kr ':�3 i.� ?M(y 4 ir `T ry�i � � �,� k k'" t � R .k�.,�� .. + >,� a� „ � �! fM ttld \^A } ,5�lM.1 3E1 � F's .�'k'� .:W� 1 " C . ' a, �4�<� ��,��h,�!�. „��u `v' d� ''YY,,tr�a +'�1��,��".R:� � ��xF..:�� s�ti'G�{n 3K1�"�";'(j'� i,. d�V�� .,��" � „�r J � �.,,t 1 '�1aa�.;�"i' h�t r '""��t , >� � �'ti�� ,�;. � �i.e,� ^y r i�"t+�� V�'e,�'�ys� :, 4'�`l�+" ',s'� ;l`fi c��h4 rrv��, '�� - Ri�4'C` d � :�� S 't YE,� � ,��+s� S•\�3�M^'Y ��,� ��y� �2 �4''� �s�i'' ✓ + y' � �*C ry'L ib P�'� N `f M \ d'�Jk� � \ �p� ¢ � 1.C � ��' �, 5 l� f�� )`f H � t��Yl��'�*P '�Fy�h�, � n q Y rA� . . '''�� f"'�c a ^j�'c �`�9 � yp ° � .•v',� 43 2 � '�5y�,.��A � �AA'd`� M'. :1,�" � ne.c��G�,7 �'.�t r " �� \ �� '� � � �' � x ��, � a ra�`� , � � � u� �' i�b� A .i 4 �QY � A1�44,t. �"�,! . �.h4 L�4'fk�� . n. . � � . .�� ; „� . S ��` � � .. .{Q tY \y .bf �/ C �+ ,. . . �fl�'YH5NNi/,. 4wiR0.�y'�V Y.kyn" . .. .��,, . :Y�f.sf31Yr 4`W�vY�:�5.4pM��"�.<4l a��tl:':.�vu�.�.1..,UR6..�aJw�kVn'nM.1.W<<.�rt++�ntiG�a.u,i�"��(c.aYWSfan'�wuFM1�.,4ek.r'�Wiw Yw�.T.�.'G�a4. : i t ; IMPORTANT INFORMATION ABOUT YOUR '�! GEOTECHNICAL ENGINEERING REPORT More construction problems are caused by site subsur- technical engineers who then render an opinion about , i face conditions than any other factor. As troublesome as overall subsurface conditions, their fikely reaction to subsurface probiems can be, their frequency and extent proposed construciion activity, and appropriate founda- , , have been lessened considerably in recent years, due in tion design. Even under optimal circurr�stances actual � large measure to programs and publications of ASFE% conditions may differ from those inferred to exist, � � The Association of Engineering Firms Practicing in because no�eotechnical engineer, no matter how the Geosciences. qualified,and no subsurface exploration program, no ` i The following suggestions and observations are otfered matter how comprehensive,can reveal what is hidden by to help you reduce the geotechnical-related delays, earth, rock and time. The actual interface between mate- � cost-overruns and other cost[y headaches that can rials may be far more gradual or abrupt than a report occur during a construction project. indicates.Actual conditions in areas not sampled may f 7 differ from predictions_ Nothing can be done to nrevent tfie , , unanticipated,but stens can be taken to help minimize their A GEOTECHNICAL ENGINEERING impact. For this reason, most experienced owners retain their � ' REPOR? IS BASED ON A UNIQUE SET 9eotechnical consultants through the construction stage, to iden- tify variances,cond�ct additional tests which may be OF PRO)ECT SPECIFIC FACTORS needed,and to recommend solutions to problems encountered on site. A geotechnical engineering report is based on a subsur- ', face exploration plan designed to incorporate a unique SUBSURFACE CONDITIONS set of project-specific factors. These typic211y inc{ude: I the general nature of the structure involved, its size and CAN CHANGE ! ' configuration; the location of the structure on the site � and its orientation: physical concomitants such as Subsurface conditions may be modified by constantly- access roads.parking lots,and underground utilities, changing natural forces. Because a geotechnical en�i- and the level of additionat risk which the dient assumed neering report is based on conditions which existed at , by virtue of limitations imposed upon the exploratory the time of subsurface exploration,construction decisions j program. To help a�oid costly problems,consult the should nnt be based on a geotechnical engineering report whose I geotechnical engineer to determine how any factors Qdequary may Fiave,heen a(fected by time. Speak with the geo- which change subsequent to the date of the report may technical consultant to leam if additional tests are , affect its recommendations. advisable before construction starts. , Unless your consulting geotechnical engineer indicates Construction operations at or adjacent to the site and ' otherwis2, your geotechttical engineering report shoule!not naturai events such as floods,earthquakes or gr�und- be use�: water fluctuations may also affect subsurface conditions •When the nature of the proposed structure is and. thus, the continuing adequacy of a geotechnical changed, for example, if an office building will be report. The geotechnical engineer should be kept I - , erected instead of a parking garage, or if a refriger- apprised of any such events,and should be consulted to ated warehouse will be built instead of an unre- determine if additional tests are necessary � � frigerated one; •when the size or configuration of the proposed GEOTECHNICAL SERVICES ARE structure is altered; PERFORMED FOR SPECIFIC PURPOSES •when the location or orientation of the proposed AND PERSONS structure is modified; •when there is a change of ownership.or Geotechnical engineers' reports are prepared to meet , •for application to an adjacent site. the specific needs of specific individuals. A report pre- � Geotechnical enyineers cannot accept responsibi�ity Jor pra6lems pared for a consuiting civil engineer may not be ade- which may develon i�they are no1 consulted a/ter/actors consid- quate for a construction contractor,or even some other , ered in their report's devetonment have chan_qed. consufting civil engineer. Unless indicated otherwise. this report was prepared expressly for the client involved ' and express►y for purposes indicated by;he client. Use MOST GEOTECHNICAL "FINDINGS" by any other persons for any purpose,or by the client ARE PROFESSIONAL ESTIMATES for a different purpose, may result in problems. No indi- vidual other than the dient should apply this report�or its Site exploration identifies actual subsurface conditions intended purpose without first conferring with the geotechnical only at those points where samples are taken,when engineer. No nerson shoula app[y this report/or any purpose they are taken. Data derived through sampling and sub- other than that originalty contemplated without(irst con/erring sequent labora[ory testing are extrapolated by geo- with the geotechnical engineer. A GEOTECHNICAL ENGINEERING der the mistaken impression that simply disdaiming re- REPORT IS SUBJECT TO sponsibility for the accuracy of subsurface information always insulates them from attendant liability. Providing MISINTERPRETATION the best available information to contractors helps pre- Costly problems can occur when other design profes- vent costly construction problems and the adversarial - sionals develop their plans based on misinterpretations attitudes which aggravate them to disproportionate of a geotechnical engineering report.'Ib help avoid scale. � these problems,the geotechnical engineer should be READ RESPONSIBILITY ' retained to work with other appropriate design profes- sionals to explain relevant geotechnical findings and to CLAUSES CLOSELY review the adequacy of their plans and specifications relative to geotechnical issues. Because geotechnical engineering is based extensively on judgment and opinion, it is far less exact than other design disciplines. This situation has resulted in wholly unwarranted daims being lodged against geotechnical BORING LOGS SHOULD NOT BE consultants.To help prevent this problem,geotechnical engineers have developed model dauses for use in writ- SEPARATED FROM THE ten transmittals.These are not exculpatory clauses ENGINEERING REPORT designed to foist geotechnical engineers'liabilities onto someone else. Rather,they are definitive dauses which Final boring logs are developed by geotechnical engi- identify where geotechnical engineers' responsibilities neers based upon their interpretation of field logs begin and end. Their use helps all parties involved rec- lassembled by site personnel)and laboratory evaluation ognize their individual responsibilities and take appro- of field samples.Only final boring logs customarily are priate action. Some of these definitive clauses are likely induded in geotechnical engineering reports.These togs to appear in your geotechnical engineering report,and shoutd not under any circumstances be redrawn for inclusion in you are encouraged to read them closely Your geo- architectural or other design drawings,because drafters technical engineer will be pleased to give full and frank may commit errors or omissions in the transfer process. answers to your questions. Although photographic reproduction eliminates this problem,it does nothing to minimize the possibility of OTHER STEPS YOU CAN TAKE TO contractors misinterpreting the logs during bid prepara- tion.When this occurs,delays,disputes and unantici- REDUCE RISK pated costs are the all-too-frequent result. Your consulting geotechnical engineer will be pleased to To minimize the likelihood of boring log misinterpreta- disc�ss other techniques which can be employed to mit- tion,give contractors ready access to the comnlete geotechnicaf igate risk. ln addition,ASFE has developed a variety of engineering report pre�ared or authorized for their use. materials which may be benef icial. Contact ASFE for a Those who do not provide such access may proceed un- complimentary copy of its publications directory Published by THE ASSOCIATION OF ENGINEERING FIRMS PRACTICtNG IN THE GEOSCIENCES 8811 Colesville Road/Suite G106/Silver Spring, Maryland 20910/(301) 565-2733 0788/3M ! : 1 . ! ; ,��;�,,: ` �r', J��rt�1 C;()17SU�fc�ll7tS I�IC. ( � � ` , ! � ��i �1 `�� l.�' <,rr>tr:•�.t�n'�ir�al Lnysin.��rs.G�rIogLSL&F.n��ir<tt-imrntal5cientisis � ( ,\t \� � � : i ` ! May 2, 2002 E-10116 ; i . , Mr. Michael Prittie � 8910 — 8'" Avenue Northeast . Seattle, Washington 98115 � Dear Mr. Prittie: We are pleased to submit our report titled "Geotechnical Engineering Study, Mapleton Residential Development, 664 Sunset Boulevard Northeast, Renton, Washington." This report presents the results of our field exploration, selective taboratory tests, and engineering analyses. The purpose and scope of our study were outlined in our March 29, 2002 proposal. Based on the results of our study, it is our opinion the site can be developed generally as , planned. Support for the proposed single-family residences can be provided using conventional spread and continuous footing foundation systems bearing on competent native soils or on structural fill used to modify site grades. The competent native soils suitable for support of foundations were observed at depths of approximately two to three feet betow existing grade. We appreciate this opportunity ta be of service to you. If you have any questions, or if we can be of further assistance, please call. Respectfutly submitted, ARTH SULT TS, INC. r on . C a E. Project Manager MGMlHAC/jme 1805- 136ih Place fd.E.Suiie 201,Bellevue,lNashi�gion 980Q5 Belle•due(425�16�13-3780 FA},(425}746-08f0 Toll Free(888)739-66iG � f TABLE OF CONTENTS E-10116 PAGE 3 INTRODUCTION ............................................................................................. 1 � Generat..................................................................................................... 1 ProjectDescription...................................................................................... 1 � SITE CONDITIONS .......................................................................................... ', Surface............................•--....................---............................................... 2 Subsurface................................................................................................ , 3 ` ( Groundwater ............................................................................................. � , 4 ; Laboratory Testing...................................................................................... 5 ; DISCUSSION AND RECOMMENDATIONS............................................................ 5 General..................................................................................................... 5 Site Preparation and General Earthwork .......................................................... 6 FillSlope Placement.................................................................................... 8 Foundations............................................................................................... 8 RetainingWalls ......................................................................................... 10 Rockery Recommendations.......................................................................... 11 Water Quality Bioswale Liner ...................................................................... 11 Slab-on-Grade Floors ................................................................................. 12 Seismic Design Considerations..................................................................... 12 , Excavations and Slopes .............................................................................. 13 SiteDrainage ........................................................................................... 14 InterceptorDrain ....................................................................................... 15 Utility Support and Backfill ......................................................................... 16 PavementAreas ....................................................................................... 16 LIMITATIONS................................................................................................ 17 Additiona[ Services .................................................................................... 17 Earth Consultants, Inc. i , II € � II TABLE OF CONTENTS, Continued , ' � E-10116 '� � � , , � �� i ILLUSTRATIONS i r , Plate 1 Vicinity Map ' ; Plate 2 Test Pit Location Plan � � Plate 3 Slope Fiil Placement < . Plate 4 Typical Footing Subdrain Detaif � f j Plate 5 Typical Interceptor Drain Detail Piate 6 Utility Trench Backfill a . l APPENDICES � ? Appendix A Field Exptoration - � Plate A 1 Legend , Plates A2 through A9 Test Pit Logs i Appendix B Laboratory Test Results Ptates B1 and B2 Grain Size Anafyses „ ; � . , : ; Earth Co�suitanta, Inc. : � , �, GEOTECHNICAL ENGINEERING STUDY MAPLETON RESIDENTIAL DEVELOPMENT � � 664 SUNSET BOULEVARD NORTHEAST RENTUN, WASH[NGTON ' E-10116 ', INTRODUCTION General This report presents the resuits of ihe geotechnical engineering study comp{eted by Earth " Consultants, Inc. (ECI) for the proposed Mapleton Residential Development at 664 Sunset Boulevard Northeast in Renton, Washington. The general location of the site is shown on the Vicinity Map, Plate 1. The purpose of our study was to explore the subsurface conditions at the site, and develop geotechnical recommendations for the proposed development. Our services included a test pit expioration, iaboratory testing, engineering analyses, and preparation of ' this report with geotechnical recommendations. Project Description We understand it is planned to develop a portion of the approximately one-acre site with a new residential development. Based on pretiminary design information provided by the client, the development will consist of up to seven single-family residential lots, a water quality bioswale tract, and an asphalt-paved access road extending in a north-south , direction out to Northeast 6"' Court on the south side of the site. At the time our study was performed, the site, lot configurations, existing structures, and our exptoration ' ; locations were approximately as shown on the Test Pit Location Plan, Plate 2. Based on our experience with similar projects, we anticipate the single-family residences ' will be two stories in height and will be of relatively lightly-loaded, wood-frame � ' construction with a combination of wood joist and slab-on-grade floors. We anticipate , wall loads will be on the order of one to two kips per lineal foot, with column loads of ten (10) to twent (20) ki s and slab-on- rade floor loads of one hundred fift 150 ounds . f 1 Y P 9 Y P � per square foot (psf►. Earth Consultants, Inc. GEOTECHNICAL ENGINEERING STUDY Mr. Michael Prittie E-10116 May 2, 2002 Page 2 We estimate cuts on the order of eight feet will be required to reach construction subgrade elevations in the eastern half of the site. Fill depths will range from approximately three to five feet, with the deepest fills located in the northwestern corner of the site. Where feasibfe, soils generated from the site excavations will be used on-site as structural fill. If the above design criteria are incorrect or change, we shoutd be consulted to review the recommendations contained in this report. In any case, ECI should be retained to perform a general review of the final design. SITE CONDITIONS Surfa ce The subject site consists of an approximately one-acre, rectangular shaped site located approximatety one hundred (100? feet northeast of the intersection of Sunset Boulevard Northeast and Northeast 6`h Court (see Ptate 1, Vicinity Map). The subjeci site is bounded to the north by an existing single-famity residence and undeveloped property, to the south and east by existing single-family residences, and to the west by a single-story apartment complex. Existing structures consist of a single-family residence, a garage, a kennel, and several rockeries. It is our understanding the existing residence is to remain and will be incorporated inio the proposed development. The cur�ent access for the residence will be abandoned and converted to one of the lots. The site is situated within a west-facing slope that descends at gradients of approximately twenty percent or less. The maximum elevation change within the limits � of the site is approximately fo�ty-two (42) feet atong a horizontal distance of about three hundred and ten (3101 feet as measured from the northeastern to southwestern corners of the site. Earth Consultants, Inc. . � GEOTECHNICAL ENGiNEERING STUDY Mr. Michael Prittie E-10116 � May 2, 2002 Page 3 The west side of the site is bounded by an approximately ten foot high, west-facing rockery that extends along the entire length of the site. The rockery is located along the , east side an asphalt-paved drive area for the existing apartment complex at the toe of slope within the property to the west. At the time of our subsurface exploration, the rockery appeared to be in good condition with no apparent signs of offset. Based on existing grades in the vicinity of the western property line, the rockery is likely constructed primarily against a cut slope. However, portions of the site on the upslope side of the rockery were previously graded to provide a level yard for the existing residence and appurtenant structures. As such, localized areas of fill are likely present behind the wall. No seepage was observed flowing from the rockery at the time of field work. The site is vegetated primarily with grass and localized areas containing small to large diameter trees and decorative shrubs and plants. Subsurface Subsurface conditions were evaluated by excavating eight test pits at the approximate locations shown on the Test Pit Location Plan (Plate 2). The test pits were excavated to a maximum depth of fourteen (14) feet below existing grade. Our test pit logs are included as Plates A2 through A9. Please refer to the test pit logs for a detailed description of the subsurface conditions encountered at each test pit location. A description of the field exploration methods is included in Appendix A. The following is a generalized description of the subsurface conditions encountered. At our test pit locations, we encountered a surficial layer of sod over topsoil. The topsoil and vegetation layer was typically eight (8) to twelve (12► inches thick. The topsoil was characterized by its dark brown to black color, loose consistency, and the presence of abundant roots and organic debris. The topsoil is not suitable for use as structural fill, nor should it be mixed with material to be used as structural filt. Earth Consultants, Inc. � ; � ; GEOTECHNICAL ENGINEERtNG STUDY Mr. Michaet Prittie E-10116 , May 2, 2002 Page 4 Underiying the topsoil and sod in Test Pit TP-8 in the immediate southwestern corner of ' � the site we encountered five feet of loose to medium dense fill. The fitl was comprised of a twelve (12} inch thick layer of loose poorly graded sand with silt (Unified Soil ! Classification, SP-SM) over two feet of inedium dense silty fine sand ISM) and two feet of inedium dense sift (MLy. The fill was similar to the undertying native soi! but was � characterized as fill due to the presence of a twelve t 12) inch thick layer of dark brown t ' silty sand encountered at five to six feet betow grade. The dark brown silty sand layer was very loose to loose and contained abundant small to medium diameter roots. This ` ' layer was interpreted to be a buried topsoil layer that likely reflects the original grade in � t the area of Test Pit TP-8. - ' The underlying native soil consists primarily of si{ty sand (SM) with varying amounts of gravel and localized interbeds of sandy silt IML), poorly graded sand with silt (SP-SM), poorly graded gravel with si{t (GP-GM), and poorly graded gravel {GP) to the maximum exploration depth of fourteen (14� feet below existing grade. The silt was encountered in the northeastem comer of the site from two (2} to ten and one hatf (10.5) feet below existing grade. The poorly graded gravet was encountered in the southwestern corner of the site from two and one half to ten feet below existing grade. The native soils were generally loose to approximately two to three feet below grade, becoming medium dense to the maximum exploration depth. Dense soils were encountered in Test Pits TP-2 and TP-6 at eight to nine and one half feet below existing grade. Groundwater Light to moderate groundwater seepage was encountered at Test Pits TP-2, TP-3, TP-4, TP-6, and TP-S at depths ranging from one to nine and one half feet betow grade. In - ' addition, mottled soils and increased soil moisture were encountered to widely varying depths throughout the site. The observed seepage, mottling, and increased soil moisture � within the site soils appear to be indicative of a seasonal perched groundwater condition. ' The seepage that may be encountered throughout the site during the spring and winter season is likely occurring a(ong a contact with interbeds of low permeability soils and in relatively permeable interbeds of granular material within the lower permeability soils. Groundwater levels are not static, and there can be fluctuations in groundwater levels and seepage rates, depending on the season, amount of rainfall, surface water runoff, and other factors. Generally, the water level is higher and seepage rates are greater in - al <4. i� ` 1 Earth Consultants, i . ; , � ' � GEOTECHNICAL ENGINEERlNG STUDY Mr. Michaef Prittie E-t0116 May 2, 2002 Page 5 � ; s i - Laboratory Testing � : , . , Laboratory tests were conducted on representative soil samples to verify or modify the field soil classifications and to evaluate the general physicaf properties and engineering � � characteristics of the soils encountered. Visual field classifications were supplemented by � , grain size analyses on representative soil samples. Moisture content tests were J performed on all samples. The results of laboratory tests performed on specific samples are provided either at the appropriate sample depth on the individual test pit logs or on a ° � separate data sheet contained in Appendix B. It is important to note that these test : 1 results rnay not accurately represent the overall in-situ soil conditions. Our geotechnical recomrnendations are based on our interpretation of these test results and their use in � , guiding our engineering judgment. ECI cannot be responsible for the interpretation of � these data by others. In accordance with our Standard Fee Schedule and General Conditions, the soil samples for this project will be discarded after a period of fifteen (15) days following completion of this report unless we are otherwise directed in writing. DISCUSSION AND RECOMMENDATIONS . General , Based on the results of our study, it is our opinion the site can be developed generally as 1 planned. Building support can be provided using conventional spread and continuous footing foundation systems bearing on competent native soils or on structural fill used to 1 modify site grades. Slab-on-grade floors may be similarly supported. l Zones of very loose to loose and saturated soil were encountered within several feet of the surface at five of our eight test pit tocations. These soils are unsuitable for direct � support of foundations, structural fill, and pavements. Where encountered, these soils should either be overexcavated and replaced with structural fill, or the footings extended ' through the unsuitable soil to the underlying medium dense soil. ' . i Earth Consultants, Inc. � �i �� GEOTECHNICAL ENGtNEERING STUDY Mr. Michael Prittie E-10116 ; ` May 2, 2002 Page 6 dJ � ) In our opinion, due to the presence of the existing rockery located immediately to the ° � west of the site, the proposed building foundations should maintain a minimum horizontal setback of ten (10) feet from the backside of the rockery. The proposed water quality ; � bioswale planned near the existing rockery should be adequately sealed with a geomembrane or soil liner to help prevent seepage through the face of the existing , � rockery. Additionatly, the stability of the existing rockery should be further assessed by ECI once the location and finish grades throughout the bioswale have been finalized. To minimize surcharge loading of the rockery, placement of fill and raising of site grades : � should not be performed within ten feet of the backside of the existing rockery. This report has been prepared for specific application to this project only and in a manner = ; consistent with that level of care and ski!{ ordinariiy exercised by other members of the , ; profession currentiy practicing under similar conditions in this area for the exclusive use of Mr. Michael Prittie and his representatives. No warranty, expressed or implied, is ' made. This report, in its entirety, should be included in the project contract documents < ' for ihe information of the contractor. Site Preparation and General Earthwork Building, pavement, and areas to receive structural fill should be stripped and cleared of � existing foundations, pavements, surface vegetation, organic matter, and other � ' deleterious material. Based on the thickness of the topsoil and vegetative layers observed � at the site, we estimate a stripping depth of four (4) to twelve (12) inches for the � majority of the site, and may extend to fourteen {14) inches in localized areas. ; �� Stripped materials should not be mixed with soils to be used as structural till. The stripped materials may be wasted on-site in landscaping or yard areas. The strippings may also be stockpiled and used as topsoil around building areas after the site is mass ` ; graded. tf strippings are placed on the lots after mass grading, it wilt be necessary to • � extend the foundations through the strippings and to remove the strippings from slab areas. � i ! Earth Consultants, Inc. i i 1 1 � � GEOTECHNICAt ENGINEERING STUDY Mr. Michaei Prittie E-10116 ' f May 2, 2002 Page 7 ; . � Following the stripping operation and excavations necessary to achieve construction ' ` subgrade elevations, the ground surface where structural fill, foundations, slabs, or . , pavernents are to be placed should be observed by a representative of ECI. Proofrolling ! may be necessary to identify soft or unstable areas. Proofrolting shoufd be performed under the observation of a representative of EC1. Soil in loose or soft areas, if � � recompacted and still yielding, should be overexcavated and replaced with structural fill � � to a depth that will provide a stable base beneath the general structural fill. The optional use of a geotextile fabric placed directly on the overexcavated surface may help to bridge f � unstable areas. ; , ; i , Structural fill is defined as compacted fill placed under buildings, roadways, slabs, { '• pavements, or other load-bearing areas. Structural fill under floor slabs and footings � � should be placed in horizontal lifts not exceeding twelve (12) inches in loose thickness , and compacted to a minimum of 90 pe�cent of its laboratory maximum dry density ' determined in accordance with ASTM Test Designation D-1557-91 (Modified Proctor). The fill mate�ials should be placed at or near their optimurn moisture content. Fill under pavernents and walks should also be ptaced in horizontal lifts and compacted to 90 percent of the maximum density except for the top twelve (12) inches, which should be compacted to 95 percent of the maximum dry density. During dry weather, most granular soils that are compactible and non-organic can be used as structural fill. Based on the results of our laboratory tests, some of the on-site soils at the time of our exploration were above their optimum moisture content and may not be , 1 suitable for use as structural fill if they cannot be dried back to optimum levels. In addition, laboratory testing indicates the site soils have from 3 to 43 percent fines ` � passing the No. 200 sieve. The northeastern portion of the site also contains silt soil ° with greater than 50 percent fines. Soil with fines in excess of approximately 5 percent fines passing the No. 200 sieve will degrade if exposed to excessive moisture, and � compaction and grading will be difficult if the soil moisture increases significantly above ' ' its optimum condition. , : Earth Consultants, lnc. . ; � ; } � 1 �I � � GEOTECHNICAL ENGINEERtNG STUDY , Mr. Michael Prittie E-10116 ; May 2, 2002 Page 8 � I � � If the site soils cannot be dried back to optimum moisture levels or if they are exposed to ` ' moisture and cannot be adequately compacted then it may be necessary to import a soil � , that can be compacted. During dry weather, most non-organic, compactible granutar , soils with a maximum grain si2e of four inches can be used. Fill for use during wet I, weather should consist of a fairly well graded granular material having a maximum grain ' • size of four inches and no more than 5 percent fines passing the No. 200 sieve based on ! the minus 3/4inch fraction. A contingency in the earthwork budget should be included for this possibility. ' 1 . � Slope Fill Placement � In our opinion, the placement of fill on a sloping grade is acceptable, however, where the I � � slope gradient exceeds approximately 25 percent, the fill must be adequately keyed and �' benched into the slope. As previously mentioned, fill should not be placed above the ' � existing rockery on the west side of the site. , � . , Fill placement on a slope consists of excavating a keyway at the toe of the planned fill. The keyway should have a width of about six to eight feet and a depth of at least two feet into medium dense to dense native soil. The slope above the keyway should then be � cut into a series of horizontal to slightly inward sloping benches. Typically, the benches : are excavated with a small bulldozer as the filt is brought up. The width of the bench varies with the gradient of the slope, usually the gentler the slope, the wider the bench. Plate 3, Slope Fill Placement shows a schematic diagram of the keyway and benches. i Foundations � ° Based on the results of our study, it is our opinion the future single-family residences can be supported on conventional spread and continuous footing foundations bearing on � competent native soil, or on structural fill used to modify site grades. . i . Very loose to loose and wet to saturated soils were encountered within several feet of the surface in Test Pits TP-1, TP-2, TP-3, TP-4, and TP-6. These soils are unsuitable for � direct support of foundations, pavements, or structural fill. If encountered at construction � subgrade elevations the very loose to loose or saturated soil should be overexcavated and � replaced with structural fill. Competent soils were typically encountered at two to four feet below existing grade. Earth Consultants, Inc. � � ; � � � � 1 , : � i GEOTECHNICAL ENGINEERING STUDY Mr. Michael Prittie E-10116 � � May 2, 2002 Page 9 � ; � For frost protection, exterior foundation elements should be placed at a minimum depth of il eighteen (18) inches below final exterior grades. Interior spread foundations can be f � placed at a minimum depth of twelve (12) inches below the top of stab, except in unheated areas, where interi�r foundation elements shoutd be founded at a minimum depth of eighteen (18) inches. Continuous and individual spread footings should have � ? minimum widths of sixteen i16) and twenty-four (24) inches, respectively. : i i i With foundation support obtained as described, for design, an allowable soil bearing � � capacity of two thousand five hundred (2,500) psf for the competent native soils or { structural fitt can be used. Loading of this magnitude would be provided with a theoretical factor-of-safety in excess of three against shea� failure. For short-term � i dynamic loading conditions, a one-third increase in the above allowable bearing capacity ' ' can be used. As previously mentioned, the foundations should maintain a minimum horizontal setback of ten feet from the backside of the existing rockery located along the : ; westem property line. , - With structural loading as expected, total settlement of less than one inch is anticipated with differential movement of less than one-half inch. Most of the anticipated settlement should occur during construction as dead loads are applied. j Horiiontal loads can be resisted by friction between the base of the foundation and the � � supporting soil and by passive soil pressure acting an the face of the buried portion of the � , foundation. For the latter, the foundation must be poured "neat" against competent ; native soils or backfilled with structural fill. For frictional capacity, a coefficient of 0.35 can be used. For passive earth pressure, the available resistance can be computed using ' ? an equivalent fluid with a unit weight of three hundred fifty (350) pounds per cubic foot . ; (pcf). These lateral resistance values are allowable values, and a factor-of-safety of 1.5 has been included. As movement of the foundation element is required to mobitize ful� � � passive resistance, the passive resistance should be neglected if such movement is no � � acceptable. ` � Footing excavations should be observed by a representative of ECI, prior to placing forms � } or rebar, to verify that conditions are as anticipated in this report. Density testing of compacted structural fill should be performed by ECI, as necessary. � i � � ; , Earth Consultants, Inc. ri t �� i i� ' + GEOTECHNICAL ENGINEERING STUDY Mr. Michae! Prittie E-10116 � � May 2, 2002 Page 10 � , - � ; { Retaining Walis ; : � � Due to the west sloping gradient of much of the planned development area, we anticipate f i a number of the residences will be benched into the slopes with portions of the foundation walls constructed against a cut slope. Walls constructed against cut or fiit " ? slopes should be designed as retaining walls to resist latera! earth pressures imposed by : ` the retained soils. The retaining wall recommendations pertain to foundation walls and � � free-standing retaining walls used to support cut and fill slopes. = � Walls that are designed to yield, such as cantilever retaining walls, can be designed to resist ihe lateral earth pressures imposed by an equivalent ftuid with a unit weight of thi�ty-five 135} pcf. For foundation walls that will be restrained at the top from free = movement the equivalent fluid weight should be increased to fifty (50) pcf. These values . are based on horizontal backfill conditions. Surcharges due to backfill slopes, hydrostatic pressures, traffic, structural loads or other surcharge loads are assumed to not act on the � ` wall. If such surcharges are to apply, they should be added to the above design lateral � - earth pressure. ECI can provide recommendations for surcharge loading as needed, based on the final design. The passive pressure, allowable bearing capacity, and friction coefficient previously provided in the Foundations section of this report are applicabte to � ' the retaining wall design. ; To reduce the potentiat for hydrostatic pressures building up behind the walls, the foundation walls and free-standing retaining walls should be backfilled with a free-draining � � material extending at least eighteen (181 inches behind ihe wall, and extending afong the entire height of the watl. The remainder of the backfi{I should consist of structural filt. � � The free-draining backfill should consist of free draining granular material comprised of � � either pea gravel or washed rock. A filter fabric should be used to separate the free draining gravel from the remainder of the watl backfill. A rigid, schedule 40, perforated �; PVC drainpipe should be placed at the base of the wall and should be surrounded by a � ' minimum of one cubic foot per lineal foot with three-eighths inch pea gravel. The pipe ; should be placed with the perforations in the down position. : ; I . 1 Earth Consultants, Inc. � ; F-I � � i � � f GEOTECHNICAL ENGINEERING STUDY Mr. Michael Prittie E-10116 � � May 2, 2002 Page 11 � � Rockery Recommendations t � Review of the preliminary grading plan indicates the planned development will include ; ; construction of a rockery along the east side of the site. The proposed rockery as � t depicted on the site plan will extend approximately two hundred t200} feet in a north- t ; south direction along the backside of ihe eastern lots. The rockery will be up to ten feet i in height and will be constructed against a cut slope. ; i Due to the close proximity of the proposed rockery to the east property tine, EC{ should � � review the final rockery design and proposed cut depths. Based on the soil conditions observed at the test pit locations, face stability of the rockery cuts may be a problem : j for cuts in excess of four feet. Terraeing the rockery is one approach that can be ' considered for minimizing the depth of the rockery cuts. Water Quality Bioswale Liner . - To help reduce seepage from occurring through the existing rockery along the west side of the property in the vicinity of the proposed bioswale, in our opinion, the bioswale shou(d be lined with a low-permeability soil liner. The liner should consist of ; at least eighteen (18) inches of a low-permeability soil meeting the foflowing gradationaf recommendations: Soil Liner Gradationat Recommendations i Sieve Size Percent Passing � 3 inch 100 ' ' #4 70 — 100 - , �f200 30 — 100 : f The native silt (ML) encountered at TP-2, TP-3, and TP-4 and some of the nafive silty ; � sand (SM1 should generally meei these gradational recommendations. The soils that are � } to be used as iiner material should be observed and tested to assess the suitability of the material. ` � , � � � Earth Consultants, Inc. Ii � 1 'f , l ' ' GEOTECHNICAL ENGINEERING STUDY Mr. Michael Prittie E-10116 � � May 2, 2002 Page 12 � The liner should be placed in six inch loose lifts, moisture conditioned to within 2 percent of optimum moisture and compacted to at least 95 percent of maximum dry density per ASTM D-1557. Use of a geomembrane liner can also be considered. ECI can provide geomembrane recommendations if requested. Slab-on-Grade Ftoors ; Slab-on-grade floors may be supported on competent native soil subgrade or on structural fill used to modify site grades. Subgrade soils disturbed during construction should either be compacted in-place to the requirements of structural fill or overexcavated and replaced with structural fill. ' The slab should be underlain by a capillary break consisting of a minimum of four inches of free-draining sand or gravel. In addition, a vapor barrier such as a 6-mil plastic membrane should be placed beneath the slab. Two inches of damp sand may be placed over the membrane for protection during construction and to aid in curing the concrete. Seismic Design Considerations The Puget Lowland is classified as a Seismic Zone 3 in the 1997 Uniform Building Code � (UBC). Earthquakes occur in the Puget Lowland with regularity, however, the majority of ; these events are of such low magnitude they are not felt without instruments. Large earthquakes do occur, as indicated by the 1949, 7.2 magnitude earthquake in the Olympia area, the 1965, 6.5 magnitude earthquake in the Midway area, and the February, 2001, 6.8 magnitude Nisqually earthquake. There are three potential geologic hazards associated with a strong motion seismic event at this site: ground rupture, liquefaction, and ground motion response. I Ground Rupture: The strongest earthquakes in the Puget Lowland are widespread, ' subcrustal events, ranging in depih from thirty 130) to fifty-five (551 miles. Surface � faulting from these deep events has not been documented to date. Therefore, it is our ; opinion, that the risk of ground rupture at this site during a strong motion seismic event is negligible. Earth Consultants, Inc. GEOTECHNICAL ENGiNEERiNG STUDY Mr. Michael Prittie E-101 'f 6 May 2, 2002 Page 13 Liquefaction: Liquefaction is a phenomenon in which soils lose all shear strength for short periods of time during an earthquake. Groundshaking of sufficient duration results � in the loss of grain to grain contact and rapid increase in pore water pressure, causing the soil to behave as a fluid. To have a potential for tiquefaction, a soil must be cohesionless with a grain size distribution of a specified range (generally sand and siltl; it must be " loose; it must be below the groundwater table; and it must be subject to sufficient magnitude and duration of groundshaking. The effects of liquefaction may be large total and/or differential settlement for structures founded in the liquefying soils. � In our opinion, the potential for liquefaction induced settlement of the soils encountered at this site shoufd be negiigible. Ground Motion Response: The 1997 UBC seismic design section p�avides a series of soit types that are used as a basis for seismic design of structures. Based on the encountered soil conditions, it is our opinion that soil type So, Stiff Soil Profite from Table 16-J should be used for design. Excavations and Slopes : The following information is provided solely as a service to our client. Under no circumstances should this information be interpreted to mean that ECI is assuming responsibility for construction site safety or the Contractor's activities; such responsibility is not being implied and should not be inferred. In no case should excavation slopes be greater than the limits specified in locat, state ' (WISHA), and Federal (OSHA) safety regulations. Based on the information obtained from the subsurface exptoration, the site soils encountered at our test pit locations would be classified as Type C by OSHA/WISHA. Temporary cuts greater than four feet in height in Type C soits shoutd be sloped at an inclination of 1.5H:1 V (Horizontal:Vertical). The underlying dense soils encountered at several of our test pit locations would be classified as Type B by OSHA/WISHA. Temporary cuts greater than four feet in height in Type B soils should be sloped at an inclination of 1 H:1 V. Temporary slopes in stopes that are wet to saturated should be treated as Type C soils and cut accordingly. ECI should observe temporary excavations to verify the OSHA soil type. Earth Consultants, Inc. GEOTECHNtCAL ENGINEERtNG STUDY Mr. Michael Prittie E-10116 ; May 2, 2002 Page 14 Shoring will help protect against slope or excavation collapse, and will provide protection to workers in the excavation. If temporary shoring is required, we will be available to provide shoring design criteria. Permanent cut and fill slopes should be inclined no steeper than 2H:1 V. Cut slopes should be observed 6y ECf during excavation to verify that conditions are as anticipated. Supptementary recommendations can then be developed, if needed, to improve stabitity, including flattening of slopes or installation of surface or subsurface drains. Permanently exposed stopes should be seeded with an appropriate species of vegetation to reduce erosion and improve stability of the surficial layer of soil. Site Drainage Light to moderate groundwater seepage was encountered at one to nine and one half feet below grade at five of our eight test pit Iocations. In addition, Zones of mottling and increased soit moisture were encountered at widely varying depths throughout the site. The shallow seepage appears to be indicative of a perched groundwater condition with water moving along the contact with tow permeability soits that underlie portions of the site. The deeper seepage zones and increased soil moisture appears to be occurring in relatively permeable interbeds or pockets within surrounding low-permeability soils. Depending on the season and depth of the anticipated cuts, light to moderate groundwater seepage may be encountered in site excavations. If seepage is encountered in foundation or utility excavations during constn.�ction, the bottom of the excavation should be sloped to one or more shallow sump pits. The collected water can then be pumped from these pits to a positive and permanent discharge, such as a nearby storm drain. Depending on the magnitude of such seepage, it may also be necessary to interconnect the sump pits by a system of connector trenches. The appropriate locations of subsurface drains, if needed, should be established during grading operations by ECI's representative at which time the seepage areas, if present, may be more clearly defined. Earth Consultants, Inc. £ } i f : ) f � � ` GEOTECHNICAL ENGlNEERING STUDY Mr. Michael Prittie E-1011 fi � � May 2, 2002 Page 15 l � f During construction, ihe site must be graded such that surface water is directed off the � � 1 site away from bui t ding areas an d areas to receive fi l l. Water must not be a i lowe d to , _ � stand in areas where buildings, stabs, pavements, or fil{ stopes are to be constructed. �, Loose surfaces shoutd be sealed by compacting the surface to reduce the potential for ', moisture infiftration into the soils. Final site grades must aflow for drainage away from ' ' � the building foundations. The ground should be sfoped at a gradient of 3 percent for a �: 1 distance of at least ten (101 feet away from the proposed residences, except in paved areas, which can be sloped at a gradient of 2 percent. ' E � � Footing drains should be installed around the perimeter of the residences, at or just below the invert of the footing, with a gradient sufficient to initiate flow. A typical detail is � � provided on Ptate 4. Under no circumstances should roof downspout drain lines be ` ' connected to the footing drain system. Roof downspouts must be separately tightlined to . discharge. Cleanouts should be installed at strategic locations to allow for periodic : ' maintenance of the footing drain and downspout tightline systems. i Interceptor Drain , Based on information provided by the ctient, we understand localized areas within the ; limits of the site are wet to saturated at certain times of ihe year. At the time of our field exploration, we observed localized wet spots in the lawn areas, and zones of {ight ° ? to moderate pe►ched groundwater seepage within several feet of the surface. Based � on the observed site conditions, the saturation is likely a result of shallow, perched groundwater accumulating along inte�beds of low permeability soils located within ; several feet of the surface throughout the site. : i ; While much of the shallow seepage could be collected by footing or � � foundationlretaining wall drains, in our opinion, it rnay be prudent to install an interceptor drain or a series of interceptor drains on the east side of the site or along � the east side of the proposed residential lots to collect and divert shallow groundwater � from the proposed building and lawn areas. If interceptor drains are installed, the locations can be determined in the field during grading as groundwater conditions within each of the lots is further assessed. Earth Consultanta,I�c. i £ , _ � : a ' i ; , � ' GEOTECHNICAL ENGINEERING STUDY Mr. Michael Prittie E-10116 ': ; May 2, 2002 Page 16 ; : , ' � Please refer to Piate 5 for a schematic drawing of a typical interceptor drain. : � '` ' Util'rty Support and Backfill Based on the subsurface conditions encountered, the soits expected to be exposed by ' � utility excavations should provide adequate support for utilities. , , Utility trench backfill is a primary concern in reducing the potential for settlement a(ong utility alignments, particularly in pavement areas. It is important that each section of j utility line be adequately supported in the bedding mate�ial. The material should be hand � , tamped to ensure support is provided around the pipe haunches. Fitl should be carefutly placed and hand tamped to about twelve (12� inches above the crown of the pipe before heavy compaction equipment is brought into use. The remainder of the trench backfill should be placed in lifts having a laose thickness of less than twelve (12) inches and compacted. A typical trench backfill section and compaction requirements for load supporting and non-load supporting areas is presented on Plate 6. Pavement Areas The adequacy of site pavements is related in part to the condition of the underlying subgrade. To provide a properly prepared subgrade for pavements, the subgrade sh�utd be treated and prepared as described in the Site Preparation and Genera/ Earthwork section of this report. Fill in public right-of-way areas should be compacted to 95 percent of the maximum dry density tper ASTM D-1557-9'i). It is possible that some localized areas of soft, wet or unstable subgrade may still exist after this process. Therefore, a greater thickness of structural fitt or crushed rock may be needed to stabilize these localized areas. ; The following pavement section for tightly-loaded areas can be used: ' • Two inches of asphalt concrete tAC► over four inches of crushed rock base (CRB) s material, or ' • Two inches of AC over three inches of asphalt treated base (ATB) materiaf. i Earth Consultants, Inc. - GEOTECHNICAL ENGINEERING STUDY Mr. Michael Prittie E-10116 May 2, 2002 Page 17 We will be pleased to assist in developing appropriate pavement sections for heavy traffic zones, if needeci. Paverneni materials shouid confarm to WSDOT specifications. The use of a Class B asphalt mix is suggested. LIMITATIONS � Our recommendations and conclusions are based on the observed site materials, selective laboratory testing, engineering analyses, the design information provided us, and our experience and engineering judgment. The conciusions and recommendations are professional opinions derived in a manner consistent with that level of care and skilt ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. The recommendations submitted in this report are based upon the data obtained from the test pits. Soil and groundwater conditions between test pits may vary from those encountered. The nature and exient of variations between our exploratory locations may not become evident until construction. If variations do appear, ECI should be requested to reevaluate the recommendations of this report and to modify or verify ihem in writing prior to proceeding with the construction. Additional Services As the geotechnical engineer of record, EC{ should be retained to perform a general , review of the finai design and specifications to verify the earthwork, foundation and � infiltration recommendations have been properly interpreted and implemented in the design and in the construction specifications. ` ECI should also be retained to provide geotechnical engineering services during construction. This is to observe compliance with the design concepts, specifications or recommendations, and to facilitate design changes in the event subsurface conditions differ from those anticipated prior to the start of construction. We do not accept responsibility for the performance of the foundation or earthwork unless we are retained to review ihe construction drawings and specifications, and to provide construction observation and testing services. Earth Conaultants, tnc. ! ' � ; 1 -- --- — -- - . . . '. . . . c:� � `�4�'. itE 3�A� �� N 33R4 : `'t:'. 8 s � � f � � � � � � ' i �4 _N '.. '�ND-..::... �� - '' � � CDLDIdAI � �.701 � ; ' _ A77NT � H 31�T- ST� � �, � '�� N� 3i5S `i r Y � '� y � � '„`��'�..`� , ' , � t�� J TE� � s-r ?� ;�,�� ' ynp � � 13C*0 ,r` a '3' .� t � - � i �"- .29T}� - �� 5j a c�r ��} �� t �'�✓r�:��,r.2�� ....'� .� .8 � � N 2$11i:: P ��v rtc� :� 'Q - �:&�. s _ �` r� �;, �iE 2$I�f , ,� �. N T .-_----- __ , j � -- e-`� t �PL ,�f�� .� �.�7TF[? 1 � Lt1 t1� - '4'�; s �� c� ne z k�� zfo� z ' ';R, � "� � sr v�' x�f��P'ir�fC � � .� �� • w �,.� .'�`. :; ,. . � , .'� � 1z � `��= s� > ,�`�. `a i � � (,/�T - .: � - � 4 - S--— ��,�,�. � - � �!I1 I�U I OlY `�J. �ea�kst ? 179d� _ � - �;- y ' j�' Q � HE:� `.: . , : �,� �, � 'c��zr�a s� :�. � i _ - � _ " tt r+ � ��a � ,2�s► � �_ � � 1 _ 3 � -':j Gj' t�' � � � ��':3;�. _ E- �. �;� 2Qn'E �cl�+ST� { t . 1 � in{a i7�o 'yr� n = r ` ;� � �� i J _� - . . . � � w � -. . NL leT►S� . .,. .. ��-- � �_ . �.�� y��. I ' ? 17m $�` � � Y �� G �d ': � . .�_--- ` � _ f :H •• a �2� BC347 .� =; r * `'�''; � ~� � } � 1�=� `.�� w '_-'��.��4 �I . � � � _ `- '` `'�I47N�, � � � m=dE si ` �-iGF/1f ctkl[au S� : � � f � 2TH ^6 �.� � �� := � � Nti_,¢�12TH: ST — �'�_ y� .i 2]Q5 � � . -- , � � �, ��? ��-.,, : � F , -¢� N ��K s;� � � �rra, � � ,� p p,Rit �5 2a7M �� Mwrt.'rra� ';� � -�� ;� 115 �ST � �X_ AIRfY)R7 � ,-�� J, �" ��` *�,� �� ' � _ _- ; t ,�� ll y� �` - 7I5 PL :� t.-_ _ � � riCN7 LAiNIC7� _�— � t�� , tE. 1DTH �� i L � � � 5 T SR�i��r v� 1 . �f�t I�1G ♦ j _ � � .etur �{,� p I{E l OTH 7T}i �5T �� , �`�i ftElYTrby 4 �J,�� , 4�; ' 1 'L S 1l7�1 PL J' { '"'i � =� rP b `'v' � I '� � NE 971! P 1 _ � � ,� - - ; � �M`�7L� „i ` � } �� ;h � �� N� � 7H � i `� � � �� = NE $YN:. ' 7 :� ' z 8 �, � � '� � �_�Sz 4 � y ;:� cfrzaa '` R; sTtj ST y ,1 � ' j 5T - -��9- _ __ r, �'� � ryE, : i S ��_ a � RIVER � � �a ,,p �zt � �p � � � s;usi r,, . � :TRA7L : � .K y ►� �c . � ' NW_7T}i ST= �` � = - t�- p - � ME srn � 3 ST�- "� � .. "*,-a ¢ � 1 . � fTN S7 r�� =;� nn� � ' 1 l � �'�` �r`„� �. �= �':J��J � �Y .� ti � , 1 -- �:�� r3 W�75 � _ ' __ m S� z � � � � � Earth Consultants, lnc. Reference: Geotechni�al Engineers.Geobgists 3 Env'sonmenral Sciernists � F Puget Sound Area � King Courrty/Map 626 ` By momas Brothers Maps Vicinity Map Dated 2002 Mapieton Residential Development � ':' Renton, Washington � NOTE: This plate may contain areas of color. ECI cannot be responsible for any subsequent Drwn. GLS Date Apri�2002 Proj. No. 10116 misinterpretation of the information resutting . � from btack&white reproductions of this plate. Checked MGM Date 4/30/02 Plate 1 � , - - f l �, � Existinp Driveway � ! — — — — � — — — — — — — — — — — — — — — — — — — — — — — — — ^ rzr_-ir,g r�ockery � � � , - ,� - — — — �- — -- � , � k �- - - --��94 - - - �- - � ' ITP-4 � � �9a k � „ �Aiei�i �,van ��:1 � � _ TP-3 f _ t k —�= I, : —•— �, __i s� —■_ ` NG ` ` ; . �TP-5 �-- - - :_ - _ _ _ _=�6 _ _ . t k� ,� �� N ;, ; ;�; -- -- - - � } �-LL � �A T 1 ' ^i" '�' li1 I �I i � ,'•� _;� ��' y`L i �I :_ _ ' I � �; I '�- � � � —_ _ - - --- -- - -=e�- I � � < �.. �, ', � i � - - _ _�--�- -� _�:.� � . � � � , O - y ' . . -- - -- I " �js t` iCti6 122- - -I I • �� .—_-` .-. .—. -I--� . _� � : � .,� /`- - , � � ' '_ � � � � .- � � 174 �� .� � � . �� _ , �� -� -�..� �� ^ ' R� , _.— t , , " I rro r��> /TP-6 1 : , : TP-2� �y < i - � �—:— �`' '. _ �� I � Approximate Sca{e _ E �� o�a ��---r ='- � - - = - - — -�� L 0 25 50 100ft. _�- - — - - _ � �/ Q � •, H °I . I y �— —�— —.. '' 0 � . :�' : i , P-$ ��,��.� � � . _' ,/7y�0a f/ ,I I Proposed � o � � Bioswate j ��Q�oQ � �' � ��,�, �� I . TP-1�— 1 � I �I ; I � �; f '� �TP-7 ! /_'_� G � �-��3 _ T - - - -�- = - - - - - -�- - - - - - - � `� i I / I N.E. 6th COURT ! � , . E , � . i LEGEND TP-1—i— Approximate Location of ECI Test Pit, Proj. No. E-10116, April 2002 . . Earth Consultants, lnc. i� Gedechnical Engineers,C'.r.ologis�s 6 Envionmenral Scie,n�ists , , u Subject Site Test Pit Location Plan ' ` � Existing Building Mapleton Residential Development Renton, Washington NOTE: This plate may contain areas of cobr. ECI cannot be responsible for any subsequent Drvm. GLS Date May 2002 Proj. No. 10116 misinterpretation of the information resulting from black &white reproductions of this plate. Chedced MGM Date 5/1/02 Plate 2 � � SCHEMATIC ONLY - NOT 70 SCALE �� NOT A CONSTRUCTlON DRAWING t � , FINAI SLOPE GRADIENT !� �� =�I1 ��« f ISEE TEXTlH i- IIIr'M V� �r' E X IST►NG i � yr.� � GRADE �" y.�� ,�11`ll= 1 „� �111_ � fi � � � -11��I1 TYPICAL "BENCH"' �� =�� MINIMUM 4 FEET � r�� ht;'nl ' t � I�I'�1�1 WIDTH � _...'.;....— ; IfH--l►1 .> ,•. ..KEY� i i� h�_�u-n� ��►�I ` j EXISTING �� : � GRADE ' l LEGEND � Free draining, organic free, 9ranular material with a maximum size of 3 inches, containing no more than 5 percent fines Isilt and clay size particles passing the No. 200 mesh sieve I or ' other material approved by geotechnical engineer. � Key way fill is same as structural fill described above. Key way should be minimum 2 feet deep and 6 feet wide, extending the full length of the stope face. ---- Approximate ori9inal ground line. NOTES: � Slope should be stripped ot topsoil and unsuitable materials prior ; j to excavating key way or benches. • Benches will typically be equal to a dozer blade width, approximately , � 8 feet, but a minimum of 4 feet. • Final sbpe gradient shoutd be ' 1 Horizontal:Vertical I. ` • Final slope face should be densiTied by over building with compacted lill and trimming back to shape or by compaction with do2er or roller. � � • Planting or hydroseeding slope face with a rapid growth deep rooted , I vegetative mat will reduce erosion potential 01 slope area. • Use ot pegged in place jute matting or geotechnical fabric will help , maintain the seed and mulch in place until the root system has an ! opportunity to germinate. ' ` • Structural fill should be placed in thin loose lifts not exceeding 10 inches in thickness. Each lift should be compacted to no less than i the degree speciiied in the site preparation and earth work section i of this report. No additional lift should be placed until compaction is achieved. „ SLOPE FILL PLACEMENT �i Ealrtl�l COI�ISUItaI1tS II�IC. Mapleton Residential Development � � iV�I �;..,, ;� G-a�rta,ical Er,gswcrs.c.bingists 6 6rv��a.m,a scienr�s�s R2I1 t O R� W3 S il lit g t Otl , Proj.No. 10I16 Drwn. GLS DateMay 2002 Checked MGM Dated 5/1/02 Ptate 3 � � f � � f f t � 0 i � ; R �— Slope To Drain _ ,;_ o �e , o eo •'o � o0 � - o • -o o . e , � , Y ,o� � � 6 inch min. '` ....� ' >: ' . .� �o - 0 � � ' �� ,e 0 0 . - � �b • �� o..�, e � �' O• o' �� - .• . .� e� . .o . o D , t �• ,�•��'•�'.�'• �� e ',� ei. ', � o O •%'I ,�. �-;o'•�`''°�4'-: '-::'•°.'o� ': � ° 18 inch min. ..;;:::��;o _:�.;•�.. •��,:. •:_ ..;- �; o-. - - � .',�:' ;: : ' �:�:� '_..�:"�o-�,'�.'�� .o o e` _ ! �. ',e�:o=: ':''•� ..•"� .•�:--•'•.' ^ ' o � r �,� ,'e•';o. •�'� •�o•�.� o ,e � o .� • 'o• ,�• ,• ,� •�'� �•�O�'• .�.�•�e -�• •� oo � O • , 4 inch min. �o- �� .;.� .. ;.• . :• e. o _ . �, 'q�'�� •O• :"� •�• oo O 0o O . .I. � � Diameter •: �.-: 'o � .o e •i� •': o 0 0 . • •� o 0 0 Perforated Pipe� :`'..:�.:,-o:;-a::�e. :.;.' _ �o o `o^o s.o 0 •••-'• ,-•� : ' �� e o 0 0 0 , Wrapped in Drainage I•�. .••= : _ .'� �_� � • � ` � • �� "' � z :- • _ '.:�o', _ o, o 0 '�. o �o � :o 0 0 � Fabric '..•:�, :'.. :.:. - i i ,. �. � •-� � 2 inch min. � 2 inch min. / 4 inch max. 12 inch min. � SCHEMATIC ONLY - NOT TO SCALE , NOT A CONSTRUCTION DRAW{NG i . ; LEGEND , i , � �';�`�:��`�;:;`-�� Surface seal; native sod or other low permeability materiat. _:'ri_::r_+;i_,t. =:r•::�:::-.. .; � Fine aggregate for Portland Cement Concrete; Section 9-03.1(2) of the -::a=�" WSDOT �pec�cations. ODrain pipe; perforated or slotted rigid PVC pipe laid with perforations or � slots facing down;tight janted;with a positive gradient. Do not use flexible , % corrugated plastic pipe. Do not tie building downspout drains into footing {ines. Wrap with Mirafi 140 Filter Fabric or equivalent. i � Earth Consultants Inc. nP�CAL FOOTING SUBDRAIN DETAIL Mapleton Residential Development °°°�°`'"'��`�5`��°"""�`�� Renton, Washington Proj. No. 10116 Drwn. GLS DateMay 2002 Checked MGM Date 5/1/02 Plate 4 - � f � r � �j ' ' IlI- III-111- � III- _ .� —11f= � — ��;.�=w��,�;�.=s>::�� I I I l I I- =•Yi;-..=,� �::a��::j"; '.'"^�,y{�=}'`•"'"„K,tLs? •fiit.r :.£ t,e,y.h'ti a v.: i2" min. Y .;;t;,;.a w� � �. :..,� Geotexti{e Fabric � ,_•.;y��;t�•5��•,��,i ;�:;.��:�� :��,� Miraft 140N �,:,'�;y�h;�b��yc"�'�Yy- , •r' , t,' °��'� 'oo��:'o'.o. / ..-7 O'. � :�i =0--!�p' / .�o�o•��p,,._�� - �r :�'r• •o.. .�.♦ o: °.o:�.�°p -�:� °�o:� Subsurface Seepage .�•�•�� •p'••;•a•�• o i o . .O� , Q' , ; DePth -'-'o: - . :p• �•'.'q Varies ,�::--o_o_+o; •;o' � ' -•o o-o:o'r.••�'o��'.o � , o. :!,.�.00:�j� , : -o--•'o-:�o,'ti�'.i :�:.=�_o-.'o o.. o. :o• Subsurface Seepage .a : .a ..00t�-�:�� :i�o�oo i"!'��:o •p•,•� ':O• �'�•_ . •Q�.o• o.o.' /�J �O .. , .�•�� .�o. .�.o ■'. -o _ �• o• � .��,p 2tl :j',' �.0:��,••'�O 0 I I . : 12" min. LEGEND width ,;_»'�•s'-''«'�:. '=�.: Native Sal Backfill j �. - , o o- •o� Free-Draining Backfill composed ::�;: of Washed Gravel, Pea Gravel, SCHEMATlC ONLY- NOT TO SCALE ' etc. NOT A CONSTRUCTION DRAWING ` /'1 Minimum 4 inch Perforated Rigid � i C � Schedule 40 POVC Pipe wrapped with Mirafi 140N Filter Fabric or equivalent placed at a � positive gradient to a suitable ` permanent discharge facility. EaPtrl COI�lSU1taI�1�S, �I�IC. Gedechrucal Engineers.Geolog�sts 6 Envkortrt�l Sciernis�s - . TYPICAL INTERCEPTOR DRAlN DETAIL NOTE: The depth and lateral extent of the inter�ceptor trench should be established by Mapleton Residential Development a field representative from this office during Renton, Washington ' ' construction. Drvm. GLS Date May 2002 Proj. No. 101 i 6 � - Checked MGM Date 5/?J02 Piate 5 - Non-Load Supporting Floor Slab or Areas Roadway Areas .._,^..��.... , - ; - , � o • Q o Varies _ o�oo°0 95 0 ° o. �oo• o 0 85 95 1 Foot Minimum Backfill 80 90 `- - . Varies - ? p�•o.�.'e PIPE 000a0.o; � �•.U�'.Oo o�jGfQ o�C3 0 . - -.sp�� .40. b•e�.o � Beddin e•;.o�:0.. o.. .o..".�"O'.•�Oe.� Varies 9 - . ��••d •e•�� o.o::'-o0'Qo:�oO•o:-- ��Do�•°0°0�.• o p0o" o• O •o'��Q'°'•/jp�° ''O' OU�O�(�'pGoOo�oO!p80O O� .00uQ.�"'�•�,??'i�. '°'O•"••oQo'p�Qo°-Q�''°0°.Q:d��"O�'o�O�oe LEGEND: Asphalt or Concrete Pavement or Concrete Floor Slab e o o a°� o , � o• Base Materiai or Base Rock � Backfill; Compacted On-Site Soil or imported Select FNI Material as Described in the Site Preparation of the General Earthwork Section of the Attached Report Text. t 95 � Minimum Percentage of Maximum Laboratory Dry Density as ; Determined by ASTM Test Method D 1557-91 (Modffied Proctor), ' Unless Otherwise Specified in the Attached Report Text. � Bedding Material; Material Type Depends on Type of Pipe and '°a•b.�°o;0� LaYing Conditions. Bedding Should Conform to the Manufacturers Recommendations for the Type of Pipe Selected. TYPICAL UTILITY TRENCH FILL Earth Consultants inc. Mapleton Residential Development �°'�a„''�'E"�,�.��'S'�"�°"",�"a's`'P'"`� Renton, Washington Proj. No.10116 Drwn. GLS Date May 2002 Checked MGM Date 5/1/02 Plate 6 APPENDIX A FtELD EXPLORATION E-10116 Our field exploration was perfo�med on April 4, 2002. The subsurface conditions at the site were explored by excavating eight test pits to a maximum depth of fourteen {14) feet below existing grade. The test pits were excavated by Northwest Excavating, subcontracted to ECt, using a rubber-tired backhoe. The approximate test pit locations and elevations were determined by pacing from site features depicted on a preliminary site plan provided by the client. The locations and elevations of the test pits should be considered accurate only to the degree implied by the method used. These approximate locations are shown on the Test Pit Location Plan, Plate 2. The field exploration was continuously monitored by a geologist from our firm, who classified the soils encountered, maintained a log of each test pit, obtained representative samples and observed pertineni site features. All samples were visually classified in accordance with the Unified Soil Classification System which is presented on Plate A1, Legend. Logs of the test pits are presenied on Plates A2 through A9. The final logs represent our interpretations of the field logs and the results of the laboratory tests on fiefd samples. The stratification lines on the logs represent the approximate boundaries between soil types. In actuality, the transitions may be more gradual. Representative soil samples were collected and �eturned to our laboratory for further examination and testing. Earth Consultants, Inc. MAJt7R DNtSIONS GRAPH LETTER TYPICAL DESCRIPTION SYMBOL SYMBOL 0 � (��/ Well-Graded Gravels,Gravel-Sand Andve1 Clean Gravels Q •� �� gW Mixtures,Little Or No Fines Gravelly (little or no fines) M r GP PpaFy-Graded Gfavels,Gravel- Coarse Soiis � • • Grained � � � gp Sand Mixtures,Little Or No Fines Soils More Than GM Sitty Graveis,Gravel-Sand- 5096 Coarse Gravels With gm Silt Mixtures Fraction Fines(appreciable Retained On amount of fines F GC C�ayey Gravels,Gravel-Sand- No.4 Sieve (�C Clay Mixfures Sand �e eo 'e SW Well-Graded Sands, Gravelly And Clean Sand � o � o SW Sands, Little Or No Fines Sandy I little or no tine�� *: y � More Than Soils O ' o ." SP Poorly-Graded Sands, Graveliy 50% Material � o'► 4_< S(� Sands, Little Or No Fines Larger Than More Than No. 20J Sieve 50% Coarse SM Silty Sands, Sand- Silt Mixtures Size Fraction Sands With Sfll Passing No.4 Fines(appreciable amount ot fines) SC SC Clayey Sands, Sand-Clay Mixtures Sieve ML Inorganic Siks&Very Fine Sands,Rock Flo�r,Siity- �p� Clayey Fine Sands;Clayey Siits w!Slight Plasticity Fine Silts Liquid Limit CL Inorganic Clays Of Low To Medium Plasticity, Gra�ned �d Less Than 50 � C� Gravelly Clays, Sandy Clays, Silty Clays, Lean Soils Clays � � � � � � �L Organic Silts And O�ganic I � I � I � O� Silty Clays Of Low Ptasticity MH Inorganic Silts,Micaceous Or Diatomaceous Fire More Than mh Sand Or Silty Soils 50% Mater�al Silts Smaller Tf�an And Liquid Limit CH Inorganic Clays Of High No.200 Sieve Clays Greater Than 50 Ch Plasticiry. Fat Clays. Size ��//j Q� Organic Clays Of Medium To High Oh Plasticity, Organic Silts `�r� ,", ,", pT Peat, Humus, Swamp Soils Highly Organic Soils �, ��r, ��i, �� pt With High Organic Contents Topsoil 'y�'y y� Humus And Dutf Layer I F�� Hiyhly Variable Constituents The discussion in ihe text of this report is necessary for a proper understanding of the nature of the material presented in the attached togs. DUAL SYMBOL3 ars used te Indtcale borderllne sdl claasfflcetlon. I C TORVANE READING,tsf I 2'O.D.SPLIT SPOON SAMPLER qu PENETROMETER READING,tsf W AAOISTURE,%dry weight � 24'I.D.RING OR SHELBY TUBE SAMPLER P SAMPLER PUSHED * SAMPLE NOT RECOVERED i WATER OBSERVATION WELL pcf DRY DENSffY,Ibs.per cubic ft. LL UQUID LIMIT,% SZ DEPTH OF ENCOUNTERED GROUNDWATER PI PLASTIC INDIX DURING IXCAVATION 1 Sl1B.SE0UENT GROUND'WATER LEVEL W/DATE � � Earth Consultants Inc. LEGEND lt1N�11X1kJIIJ�Y�'a'f!.(iIX�U�L5�S61J1YIrtMY1%1N.dSlYIIf�M� Proj. No. I0116 Date May 2002 Plate Al Test Pit Log Projed Name: Sheet d � Mapleton Residentiai Dev�elopment 1 1 Job No. Loc�ged by: Date: Test Pit No.: 10116 MGM 4/4/02 TP-1 Ezcavation Contacior: Ground Surface Ele�wation: NW E�acava6ng 185' Naes: „ o L o � o surface c«►daions: Depth of Topsoil&Sod 4" General w NO�@S (%} � �. p LL a j �. (.7 cn v� u� SM Reddish brown sitty SAND,loose, moist � ` 2 GP-GM Brown poorly graded GRAVEL with silt, medium dense, moist to wet ' . 4.4 � 3 -5%fines .. • a 5 SM Gray sitty SAND with gravel, medium dense to dense, moist s � - i�.a a s �o �.3 • �� SP-SM Gray poorly graded SAND with silt and gravel, medium dense,wet P Test pit terminated at 11.5 feet below e�as6ng grade. No groundwater encountered during e�acavation. , ' NOTE: Test pit ezcavations estimated based on topography and data shown I� , on Preliminary Site Ptan. I, e � 0 � U W � a m Test Pit Log �(� Farth Consultants Inc. Mapleton Resident'ral Development O Ccxlrt�cimk'al F11�w�5,Cw'MtiglSA 6 FmAmnnx`M�.N S('kn1L+A Renton,Washington F- a w Prq.No. 10116 Dwn. GLS Date May 2002 Chedced MGM Date 5/1/02 Phate A2 Subsurfaoe cor�tions deQided our obser►rations at the tane and Iocation of this e�loratory hole,maiified bY e�x,�i�9 tests,anaysis and ludgment. They are rrot neoess��esentative of dher tirnes and Iocations.We cannd acoept responsibility for the use or i�erpretation by others of �nf�vmd'w+n rvicennlori M�hic Lv� Test Pit Log Proied Mame: sr,eec d � t Ma leton Residential Develo ent 1 1 � ' Job No. Loc,�ed by. Date: Test Pk No-: 10116 MGM 414l02 TP-2 Ezcavafion Cantactor: Groand Surface Elevation: NW E�acavating 190' ►vaes: � o t „ � surtace cor�ditior,s: Depth of Topsoil 8 Sod 8"- 12" , . Ger�ral W Q E a ..; a c� � NOtes �/, '� �. m " � `� >. ( ) � <n � cn � �n . , y TPSL 8"-12"TOPSOIL and SOD y 1 SM Mottled brrnm silty SAND with grav�el, medium dense,wet ' z - 25-� 3 ML Mottled brown SILT, loose to medium dense, mast ' ` 4 -becomes brov►m, medium dense I 5 -light seepage in pocket of poorly graded sand 6 SM Brown silty SAND with gravel, medium dense,wet 7 8 SM Braum silty SAND, dense, moist 9 -trace small ravel, mottiin �o SM Gray silty SAND with grav�el, dense, moist to wet, 13%fines s.s Test pit terminated at 10.5 feet below e�asting grade. Light groundvvater seepage encountered at 4.5 feet during excavation_ � � � 0 � U W a t� o Test Pit Log Farth Consultants Inc. Mapfeton Residential Development 8 CxxHrcYttUcalFnglrrxys,Cw-cik�gW�fiFmAmnnxYW�lticirntHi�: Renton,Washington J a � Proj.No. 10116 �wn. GLS Da�e May 2002 Chedced MGM DaQe 5/1/02 Plate A3 W � St�su�face oonditions depic�ed re{xesent our obserwatioru at the time�d bcation ot this e�loratory hole,rt►odfied by ergineering tests,anaysis end �udgment. They are not necessarily representative d other times and locations.We canrat accept responsibldy for the use or iMerpretation by others d �ns.,.,.,�'v..,.,.oce..lo.+,...11.ie w. r Test Pit Log i� � � Projed Name: 5heet af yi � Mapleton Residential Dev�el ment 1 1 , 1 f Job No. Loc,�ed by. Date: Test Pit No.: 10116 MGM 4/4/02 TP-3 Ex�avation Contactor Ground Surfaoe Elevation� ; { NW E�acavati 195' t Notes: , � j � — m $ surfaoe c,onations: Depth of Topsoil8�Sod 12" General W L a t a `n c l n � n ..: U Notes (96) � cn � LL � � u�i � � y TPSL TOPSOIL 8 SOD � ) y � SM Brovm silty SAND, loose to medium dense,wet, light seepage at 2' +. , ; } �.0 2 ML Mot�ed brown and gray SILT with sand, medium dense, moist 3 � �: 4 � ti 5 s ML Grades to mottled brown and gray SILT with sand, medium dense, ' moist ' � � � 8 ML Gray SILT, medium dense to dense, moist I -.5"thick beds �-4 9 -contains polished surFaces and angular silt fragments in silt matroc 10 : Test pit terminated at 10.5 feet below ebsting grade. Groundwater seepage encountered at 2.0 feet during excavabon. � . , , n e � � � � , U w a � m Test Pit Log ; � Earth Consultarlts InC. Mapleton Residential Development � o �'`��*"'�"�`�R��F"Wr"��""��*"'� Renton,Washin�011 i � � Proj.No. 10116 Dwn. GLS Darte May 2002 Chedced MGM aate 5/1/02 P�ate A4 Subsuriaoe cond'itions depicted ent our abservations al the 6me and location of this e�loratory hole,mod'rFied by enginee�ing tests,analysis and �ludgment�They�nd necessM'�representative d other tenes and locations.We cannd accept responsd�ility for the use or iMerpretatian by others of � „ i ; rest Pit�og I Project Name: Shee1 of �� Mapleton Residential Development 1 1 � i Job No. Loc,�ed by. Date: Test Pd No.: 10116 MGM 4/4/02 TP-4 Fzrava6on CoMacta: Ground Surfaoe Elevation: � NW F�acavatin 185' ` f Notes: I r � f � — m surface condaions: Depth of Topsoil 8�Sod 14" � ( L �p} L a � � ) � W �E Q LL � j � O � � � � � � y TPSL 14"TOPSOIL and SOD i i ; .� 1 I SM hAottted brown silty SAND with grav�el, medium dense,wet ' � � , i ».s 2 3 -light seepage at 19" „ ' ML Mottled brovm SILT with sand, medium dense, moist ; { 4 � 1 5 i � � 6 7 ; l e SM Gray silty SAND with gravel, medium dense, moist 9 ' 11.2 10 , Test pit terminated at 10.5 feet below e�asting grade. Groundwater seepage encountered at 1.5 feet during excavafion. , . i . , � e N ' � � � � W 7 a " � m Test Pit Log � Earth Consultanrs Inc. Mapleton Residentiai Development � � CwxrrctmMdlFi�xs��.Cw�tY.niFnvlmuirnralticirntl�: Renton,Washington � Q W Proj_No. 10116 Dwn. GLS Date May 2002 Chedced MGM Date 5/1/02 Ptate A5 � _ r Subsurfaoe c�ndRions depicted represent ouf obse�vations at tt►e time�d location of this e�loratory hole,modified by engineering tests,analysis and . !^��Thay�not �►,r�cessarily representative of other times and Ioca�ions.We pnnot acoept responsibilAy for the use or interpretation by others of , j Test Pit Log Projed Name: Shee! of '1 Mapleton Residential Dev�elo ent 1 1 ' E Job No. Logged by: Date: Test Pit No.: 10116 MGM 4/4/OZ TP-5 Ezarvation Corttactor Ground Surface Elevation: ' : i NW E.�acavating 170' IVotes: , � : � o L „ � o su�tace cor�itions: Depth of Topsoil&Duff 12" : � Genera► w nE n .-: � UD Notes (%) c�7 i � LL � � i y TPSL T4PSOIL and DUFF II , y 1 „ SM Brown silty SAND with gravel,v�y loose, moist , ; 2 SM Mottied brown silty SAND witt►grav�el, loose, moist . , 3 � � 1�3 4 -abundant cobbles , , 5 -43%fines . 6 -becomes medium dense, moist � Test pit terminated at 7.0 feet below e�osting grade. No groundwater encountered during ezcavation_ i . � . � . . � e � � � r 0 � • . U W � d ' o Test Pit Log . ` � Earth COt�lsultants It`1C. Mapteton Residential Development � G�r.clttdcal Fngtih��'w Gr.�k�i.st+6 Fmlmnnrwal SckrlFa+ Renton,Washington � a �' Proj.r�o. 10116 own. GLS Date May 2002 Chedced MGM �ate 5!1/02 t�ate A6 , W � Subsurfaoe oonditions depided represent our observations at the time and location d this e�loratory hole,modfied by engineering tests,analysis ar►d . �dgmer�rt TheY are not �rracessarily representative af other times ar►d bocatans.We cannd accep�t responsibility fa the use or iMerpretation by dhers d f } Test Pit Log „ il PfOjECt�lit6: ShEet of � � Mapleton Residential Dev�elopment 1 1 ' � Job No_ ; ; �o�g�bY Date: Test Pit No.: 10116 MGM 4/4/02 TP-& Ezcavation Contada: Ground Surface Elevation- ; � NW E�acavating 180' Wotes: r j � o = m � surface conditions: Depth of Topsoil 8�Sod 2"-3" Generel W t n a $ : � �� (o�) �n T Q LL W j T � � N N , ! SM Brown silty SAND, toose,wet : 1 , � � -moderate seepage at 1' � ; 2 SM Mottted brown and gray silty SAND with grav�el, dense, moist 20.2 3 � � ij 4 t � 5 SM Gray slty SAND with gravel, medium dense,w�et s � : � s , , 2(?5 9 SM Gray silty SAND,dense, moist,contains gravel, becomes blue gray ��.� ' �� Test pit terminated at 10.0 feet below e�asting grade. Groundwater seepage encountered at 1.0 feet during e�acavation. . , � � , , � ; i i i , i N 2 n . . F 0 c� ' w � a ' o Test Pit Log � Earth Consultants Inc. Mapleton Residential Development � � $ GrqrclmkalFiiglnhaS,Cw�tik�gtSL�RFnvlrtxmxrKrlScktHl.iS Renton,Washington a W Proj.No_ 10116 Dwn. GLS Date May 2002 Chedced MGM o�ate 5!1/02 Plate A7 Subsurface conddions depicted represent our observations at the time and location d this e�loratory hole.modF'�ed by engineering tests,analysis and judgmer►t. mey are na neoessariy reExesentative or aner times and locations.we cannot acoept responsbi�ay tor tne use or irtterpretation by others ot , - ».inm�sl'v,..rvoeor.fu.l.v,Mi�4,.. : i f l ' ` Test Pit�og i ; Projed Narne: Sheet of � , Mapleton Residential Development 1 1 . ; Job No. Logged by: Date: Test Pit No.: 10116 MGM 4/4/02 TP-7 Ezcavation Contador Ground surtaoe Elevation: NW E�acavating 170' I i Notes: I ' ? �t w L D L . a � � Surface conditions: Depth of Topsoil &Sod 12" I tl �� (°�o) � `n Q � v) = N r � �, TPSL TOPSOIL and SOD : 1 �, � SM Reddish brovm silty SAND with grav�el, medium dense, moist . , 2 : ; , � . 3 GP Brown pooriy graded GRAVEL, medium dense, moist f j 4_5 w ; •. • ' � •�' 4 -3%fines � .. . � _ •'• 5 � �•� 6 . � . w 7 •. • ��' -becomes wet 5.3 �� 8 •'• 9 w ••� � � �o Test pit terminated at 10.0 feet below e�tisting grade_ No groundwater encountered during e�acavation. N Q � F D � U ' W � a � o Test Pit Log Earth Consultants Inc. Mapleton Residential Development 8 �'"w`a'"'�.'�.�*�'e�,w""'"""'�`,�`"'�' Renton,Washington a � F Proj.►�o. 10116 Dwn. GLS Date May 2002 Chedced MGM Date 5/1/02 �ate A8 � Subsurfaoe cond'dions deQided represent our obsenr�ions at the time and location d lhis e�bratory hole,modified by engineering tests,analysis and �udgmer►t. They are nd r�oessan'ly representative of other times and locations.We cannot accept responsibility fa the use or interpretation by others d � �.,.,.,�Iv,.,.,.,eca..M�1 n.,N,K w. • f � � Test Pit Log i Project Name: Sheet d �t Mapleton Residential Dev�elopment 1 1 ; � i i .Job No. Loc�ecf by: Date: Test Pit No-_ ' 10116 MGM 4/4/02 TP-8 E�xavation Contador: Ground Surfaoe Elevation: NW E�acavating 165' � � Ndes: ' � � o = d � o surfaoe condnior►s: Depth of Topsoil &Sal 2" Genef2l W L � n � Notes (% `° �, m LL' a y T ) c� �n � ,n � ,n f � SP-SM Brown poorly graded SAND with silt, loose, moist(Fill) , ; � SM Brown silty fine SAND, medium dense, moist(Fill) , t ».0 2 • 3 ML Brown SILT, medium dense, moist(Fill) I E � : i 4 i � , 5 SM Dark brown silty SAND, loose, moist, abundant roots s SM Brovm silty SAND with gravel, loose to medium dense,w�et � . i 8 9 -becomes woet to saturated �o -moderate to heavy seepage at 9.5' 20.6 - 11 12 13 -contains pockets of poorly graded sand and sandy siit 23.6 14 Test pit terminated at 14.0 feet below e�osting grade. Groundwater seepage encountered at 9.5 feet during ezcavation. i ry Q � O C1 , i W � a m Test Pit Log � �rt�1 COr1SUltc"�I1tS Ir1C. Mapteton Residential Development � O GxteAmkalFi�glrxxas G�nk�1.v�6Fmlmnnx�tK�IXN-n�Ns Renton,Washington f- a � F Proj.No. 10116 Dwn. GLS Date May 2002 Chedced MGM Date 5/1/02 Plate A9 Subsurtaoe conditions depided represent our observatians at the time and location d this e�loratory hole,modified by enginee�ing tesfs,analysis and judgrr�ent. They ere not neoessariy representatiue d other times and locations.We cannd acoep�t responsibiCdy for the use or�terpretatian by dhers d , w�frv�v�dinn rvmnnfnri rv�fhic Lv� i i 1 t i ` i � , j i i i , � ; , APPENDIX B LABORATORY TEST RESULTS E-10116 ; Earth Consultants, Inc. • � � � � � • �t7�.73.]I�.�Ii�L�ILIP.GT.[�� • • �Q�iL[��F�LLT�I ��^�.�'z - - - - - - - �� ''��u��i��r��r��■��r�� ' :� ��i�a�i��iiiii�� ' ��c:�■��■■■�� ,= •, ��'��.�� , ��a ��a��■��■�■■��■��■ ��■��■��■�� a��i��■��■�� ■�■��■��■r�� . ' � •, ��`ir■�ri•��■■��■�■��■� , ' ��■�om��n■■��■�■�■�� ■��,,��Q��■■��■� t . ��■��■�w��■■■�� .■��.�...��v��u��■■■.�� :��■��■r�n��■r�� . ��L'��7��i�� • ��r��\i��s��r��/\�� ►��T.�rY�■��■■■�� r�A��r� .� ��■��r '� ��r��\��7�� \��r�!�i"1'��■\■�� • . ��\��i��■■■�� . • � ��\�� t�r��1��r��■�� ' �r��r��\��■��\��r�■�� \�■�rl��r■�� \��a1i��■■�� • •� ��r��r��l��r��\��r� � ��■��r�l■��r��\■�� ' ��■��:��I■��■��r •. ��\��rr�i��r�� ■��n��■�� - , ��■��o��■�� - ��.�� ■��►��■��■�� ■��■��■�.��■■�s��■��■��.�� ■��■��■i��■■■�� ■��■��■��■��■�� ' ��`:��.��■�� :� ��■■�� ■��■��■�� ■��■■��u��■�� ■��:��■r��■■��■��■r��■ ' ��■��■��■��■��■ '� ��■��■��r��lilr��■�■��r ��■��r��`11��■�� ■■■�� . . � ��\�I\■il�l�l��l��ll�■�I�I��r■��11��1��1��11�� - _ _ ' _ _ . - � _ _ - - - � . • ' - �� . � �• � •', � , �� ' •� �' mm . � : • ��• . • -• . - � 1 1 . . ■ ' : • � � • . - � � � - � � � . .��ILR�.IL�L�L.�� ' • ��Q�:�L�� • . -• �� - -- - - - - �� s��.��v��■��■�� ' � '�-- ��■��■��s�� `.;"- f ��+��r��■■��r�� r��■��■��■��1■ ��.= •, ��v�� . � ��■��\71�r��r��■��■�� ■��r��■■��rr�� r��r��n�■��■�� r��i��■��■��r�r � • :� ��7��►��r�� r��i��r��■�� r�,��r��■��r� • ��I��r��s■�� t1��r��■��/�� • � ��■�� • ��•��r��r��r�� ■1��r��■��1��■■�■�� • ��■r��1��■�� \r��I�r��■■�� r��rr��l��r��r��r��r .� ' ��r�rr��■��r�� r��1��r��r��r�r��r�� \\��1��■��■�� • • ��\��r��■■��r�� . • � �r��sa:1��rr��1��r�� r.��r��si�� • •. ��\\��rr��/��r�� r��■15��■��■■■�� \\��■�■�� '� ��r��M�r��r � ��r��\��■��r ' ��!��1��■�r��■■�� • �r�r��t!��r��r��rrr��r■��r�� ■��r��[��r��■■��rr�� r�rrr��■��u��■■■��5�� rr��\'11��lr��■■�� ■��r��i��r�� \��r��■■■�� .��7��r��■�� r��r��r��r��r� . ��r��r��:7��rr��r��r�■�� .� ��r�■��r��\��r ��■��\��■/�� r��l��■�� rr��■■��rr � r��■��►��r�� '� ��■��'�1��■�� ■��■��`��r��■�� Ci�l��r��■\■�� rrr��l��l�l�l��l��ll�■�I�I��■�11��1■�ir��■11■��■��r�� . - � .�. • ' �l �� ' 1l �� - � , � , • • �� mm . � • ��• .• -• • • � / : • � � ;"�i �-2 I � 7 ! y DISTRIBUTION � � ' � E-10116 • , � � 4 Copies Mr. Michael Prittie � � 8910 — 8"' Avenue Northeast Seattte, Washington 98115 . , i , � 4I : f . � 1 • � • � I s � . I . j . � � ' II � � , � � � I . 1 ' : � . � Eahh Consultants,inc. 7.0 OTHER PERMITS Several specialized permits/approvals will be required for this project. Below is a list of the anticipated pernuts this office will seek as part of this development: 71 City of Renton Street Name and Address Approval 7.2 City of Renton Postmaster Approval 7.3 City of Renton Fire Hydrant Location Approval 10128.O15.doc [HPG/tep] 8.0 ESC ANALYSIS AND DESIGN The erosion control pIans for the I�lapleton Short Plat were prepared in accordance with ihe 1990 King County Surface Water Design Manual and the Hearing Examiner's conditions. The first phase of the project will be providing the expected limits of clearing and then [he removai of the existing garage on the property. The existing house is proposed to remain as shown on the erosion control plans. The biofiltration swale area will be constructed prior to the earthwork movement on site. This will accommodate the erosion control facility during the grading phase of the project. Once the rough grading is complete, the utilities will be installed as shown on the construction plans. The next phase of the project will be to provide subbase material and paving of the roadway. Erosion control measures included hydroseeding and the establishment of straw mulching, if necessary, on the project. 10}28.O15.doc[HPG/tep] Site Improvement Bonc� Quantity Worksheet King County Department of Development& Environmental Services 900 Oakesdale Avenue Southwest Renton,Washington 98055-1219 I Project Name: Date: ' Location: ProJect No.: Activity No.: Note: All prices include labor, equipment, materials, ove�head and Clearing greater than or equal to 5,000 board feet of timber? profit. Prices are from RS Means data adjusted for the Seattle area or from local sources if not included in the RS Means database. yes no If yes, Forest Practice Permit Number: (RCW 76.09) Page 1 of 9 Unit prices updated: 02/12/02 Version: 04/22/02 af.557.x1s Report Date: 9/27/2002 Site Improvement Bond Quantity Worksheet ; ::. > unit , #ot : , >: ;: , „ , ;. .. - ;< < �#�fetl��tCg�: ' ' ' Prtce �#ni# Quan�i ' licatlons Gast _ _ _ _ _ _ ..__._._ __ - __ _ _ _ _ _ _ _ __ __._....... ER�SIONISEDIMENT CONTROI» ' ' '" _ Backfill & com action-embankment S 5.62 CY Check dams, 4"minus rock SWDM 5.4.6.3 $ 67.51 Each Crushed surfacin 1 1/4"minus WSDOT 9-03.9 3 $ 85.45 CY Ditchin $ 8.08 CY Excavation-bulk $ 1.50 CY Fence, silt SWDM 5.4.3.1 $ 1.38 LF Fence, Tem ora NGPE $ 1.38 LF H droseedin SWDM 5.42.4 $ 0.59 SY Jute Mesh SWDM 5.4.2.2 $ 1.45 SY Mulch, b hand, straw, 3"dee SWDM 5.4.2.1 $ 2.01 SY � Mulch, b machine, straw, 2"dee SWDM 5.4.2.1 $ 0.53 SY Pi in ,tem ora , CPP,6" $ 10.70 LF i Pi in ,tem ora , CPP, 8" $ 16.10 LF Pi in ,tem ora , CPP, 12" $ 20.70 LF Plastic coverin ,6mm thick,sandba ed SWDM 5.4.2.3 $ 2.30 SY Ri Ra , machine laced; slo es WSDOT 9-13.1 2 $ 39.08 CY Rock Construction Entrance,50'x15'xi' SWDM 5.4.4.1 $ 1,464.34 Each Rock Construction Entrance, 100'x15'x1' SWDM 5.4.4.1 $ 2,928.68 Each Sediment ond riser assembl SWDM 5.4.5.2 $ 1,949.38 Each Sediment tra , 5' hi h berm SWDM 5.4.5.1 $ 17.91 LF Sed.tra ,5'hi h,ri ra ed illwa berm section SWDM 5.4.5.1 $ 68.54 LF Seedin , b hand SWDM 5.4.2.4 $ 0.51 SY Soddin , 1"dee , level round SWDM 5.4.2.5 $ 6.03 SY Soddin , 1"dee , slo ed round SWDM 5.4.2.5 $ 7.45 SY TESC Su ervisor $ 74.75 HR Water truck, dust control SWDM 5.4.7 $ 97.75 HR _ Rkv�#i:: <: :.::::::..::::::::.:::::.:.:.:.:: WR�T -� T <, :.:...::.::.:.::::;:'..;:.:..: E �hl F.�ft�.S _ see a <::>::<:>;::::><:<:::<::>«<::<::::::::::<::;:��::::::�: _ ____ Each ESC SUBTOTAL: $ - 30%CONTINGENCY& MOBILIZATION: $ - ESC TOTAL: $ - COLUMN: A Page 2 of 9 Unit prices updated: 02/12/02 Version: 04/22/02 af.557.x1s Report Date: 9/27/2002 Site Improvement Bo �uantity Worksheet _ _ _ _ _ __ _ _ _ _ _ __ _ _ __ _ ___ _ _ _ _ _ _ _ _ _ _ _ ___ _ _ __ _ _ _ __ __ _ ____ _ _ __ _ _ _ _ __ ___ _ _ __ _ ___ _ _ _ _ _ _ _ _ _ .. __ _ _ _ _ __ _ _ _ _ __ _ _ _ __ _ _ _ _ _ __ _ _ r ; < EkisYit#g i! F�hit�:Publft Prf�rBte QuanEity Gontpistad '' ;; l�tgit�ai Way;: ;: �icad.tm�rav+em�ti�s im�rnve►nents {Bo ion�� . .:.: :..... nd Reduct ;, < ,,:,:...... &�ra3na...Fa�lEdes ;! Quar�E. Llnit Arics fJY�tf:' C?ciarit, Casi Quari4< �osi:' C3�ac�E, Cast ': �m ste Cost _ _ __......_.... ............ ..................._. _ ._ .__._........ _.. _................,.... __ ___ ___.....__., ....... , .................................................... .......... ... .................,...,.._..................... .. ...... .. . ....... .. .......... Backfill&Com action-embankment $ 5.62 CY I Backfill&Com action-trench $ 8.53 CY CleadRemove Brush b hand $ 0.36 SY � Clearin Grubbin ree Removal $ 8 876.16 Acre � Excavation-bulk $ 1.50 CY Excavation-Trench $ 4.06 CY Fencin ,cedar,6'hi h $ 18.55 LF Fencin ,chain Iink vin I coated, 6'hi h $ 13.44 LF Fencin chain link, ate,vin I coated 20' $ 1,271.81 Each Fencin lit rail 3'hi h $ 12.12 LF Fill&com act-common barrow $ 22.57 CY FIII&com act- ravel base $ 25.48 CY FIII&com act-screened to soil $ 37.85 CY Gabion 12'dee ,stone fiiled mesh $ 54.31 SY Gabion, 18"dee stone filled mesh $ 74.85 SY Gabion 36'dee stone filled mesh $ 132.48 SY Gradin fine,b hand $ 2.02 SY Gradin ,fine,with rader $ 0.95 SY Monuments 3'lon $ 135.13 Each Sensitive Areas Si n $ 2.88 Each Soddin , 1'dee slo ed round $ 7.46 SY Surve in Ilne& rade $ 788.26 Da Surve in lot IocatioNlines $ 1 556.64 Acre Traffic control crew 2 fla ers $ 85.18 HR Trail 4'chi d wood $ 7.59 SY Trail,4'crushed cinder $ 8.33 SY Trail,4"to course $ 8.19 SY Wall retainin ,concrete $ 44.16 SF Wall, rocke $ 9.49 SF Page 3 of 9 SUBTOTAL Unit prices updated: 02/12/02 'KCC 27A authorizes only one bond reduction. Version: M22/02 af.557.x1s Report Date: 9/27/2002 Site Improvement Bo Quantity Worksheet ' ?.: ,: Exist#ng :: Future PubtlC :; . : .: Private �O#��Rei�iia#ion�' : " ` ` ' ' < ' .Riqht-of-way ' flvad tmpravemeeits i Im}uavements '' ; ! ' &Draina s�'acllFtles' I Qaant.::: ,: , > ; '' UrrE Price Unit Quant. �osi Qr��rtl. Gast'' QttBttt::: Cns� .>i: �am ate C�s# AC Grindin ,4'wide machine< 1000 $ 23.00 SY AC Qrindin ,4'wide machine 1000-2000 $ 5.75 SY AC Qrindin ,4'wide machine>2000 $ 1.38 SY i AC RemovaVDis osaVRe air $ 41.14 SY � Barricade e I $ 30.03 LF Barricade e III Permanent $ 45.05 LF Curb&Gutter rotled $ 13.27 LF Curb&Gutter,vertical $ 9.69 LF Curb and Gutter demolftion and di osal $ 13.58 LF Curb extruded as halt $ 2.44 LF Curb extruded concrete $ 2.56 LF Sawcut as hait 3"de th $ 1.85 LF Sawcut concrete, er 1'de th $ 1.69 LF Sealant,as halt $ 0.99 LF Shoulder,AC, see AC road unit rice $ - SY Shoulder, ravel,4'thick $ 7.53 SY Sidewalk 4'thfck $ 30.52 SY Sidewalk 4'thick demolition and di sal $ 27.73 SY Sidewalk 5'thick $ 34.94 SY Sidewalk,5'thick demolition and dis osal $ 34.65 SY Si n handica $ 8528 Each Stri in er stall $ 5.82 Each Stri in thermo lastic for crosswalk $ 2.38 SF Stri in ,4'reflectorized line $ 0.25 LF Page 4 of 9 SUBTOTAL Unit prices updated: 02/12/02 'KCC 27A authorizes only one bond reduction. Version: 4/22/02 af.557.x1s Report Date: 9/27/2002 Site Improvement Bc Quantity Worksheet , , <: ' ;. > ` r :�xisting > ;' FuEure Publia Private __ _ Bortd RaduGtfon' _ <;... ' . ' I Right-of-�etay Aoad lmpravemenis ,Improvements ; _ d�braina e�"acilities .Quant: _ '.:. ' ' '' = Urut Prlce>; ' Unii Quan�. Cos€ Qvant f�si Quarrt: ' Cost �t3°r fi� �UsT �:..:::..:•:�..::: .:.;:. . , . �:>:�>o->:.::>::.::': , ,;.:.:::.>;.j:,.:.':.:.::.'.:.:.,c y . . . . .; . :: . :::i:::..•#: `. . : : : .: .:.. �. ...:.:::::.. :::�: 1 :: : #. ... . .: '�" .:.. t: .' : 'i 1K. �Ri3F'&�.::;'��:�ili•>°�►�:.'�.'✓.�►�L•.:��.��JG�.�i�.<.>�q�$t::�:y�:o:tQ :i'�J1.�1�#::::i;'s::;?z'zit:o;:;:;:;:.::�::::l2::;:;z2;;;::l;:z�;s::::l;�;;;:�;i.;;::..;.::::::::::::::::::�;<:;s�;:.:•.::;::i;r:::>;::::.;:••:;:;:;::;•::::;.:;�,>iii:><:.;.;` :;:;::.;!�:a�+J�.:::..`+�`..'��.;�lR�!�Bi:>��s�,.:<:�:............ �.............:....::...............................................�........�......,................................................,..:::.:.::.:.... For KCRS'93, additional 2.5'base add: $ 3.60 SY AC Overla 1.5'AC $ 7.39 SY AC Overla 2'AC $ 8.75 SY AC Road 2' 4'rock, First 2500 SY $ 17.24 SY AC Road,2' 4'rock � .over 2500SY $ 13.36 SY AC Road,3',4'rock, First 2500 SY $ 19.69 SY AC Road 3' 4'rock,Q .over 2500 SY $ 15.81 SY AC Road 5',First 2500 SY $ 14.57 SY AC Road 5' Q .Over 2500 SY $ 13.94 SY AC Road 6' First 2500 SY $ 16.76 SY AC Road 6' Q .Over 2500 SY $ 16.12 SY As halt Treated Base 4'thick $ 9.21 SY I Gravel Road 4'rock First 2500 SY $ 11.41 SY Gravel Road,4'rock, .over 2500 SY $ 7.53 SY PCC Road,5',no base over 2500 SY $ 21.51 SY i PCC Road, 6",no base over 2500 SY $ 21.87 SY Thickened Ed e $ 6.89 LF Page 5 of 9 SUBTOTAL Unit prices updated: 02/12/02 'KCC 27A authorizes only one bond reduction. Vefsion: 4J22/02 af.557.x1s Report Date: 9/27/2002 Site Improvement Bo Quantity Worksheet ' ' `: r: > " i ; ExisttR3 ..::: ..... !' !: Futbre!;P41�at�a,' �+rivaie . �t�d AeduCti+�tl}: ... , ,: , <: _ ` , : Right-af-waq>i �ioad#nprvYefna�nLs Im emer�ts.. !: , , , . . __: :;. >: #� ;: <: ; _ ' _ ' r &Drair�a e Faa11�t1Es. >C�r,�alt�.,>: . _ :, : ` .... ' i. Ucn!Rric� ! Lkait Q�ant �ost ' Q�anf: �a�t : i:f�Uant:' :< �ost :: eam ete ;:�ast , ,:. ,; -, ,, _ :.......... .:: _ _ ..::::.:>•:.., : , :,...:�:;_::::.:.;:::;::,.: _„ -; . ,:,. :>:4��:-�01`!4i �i�:�&��i� �'��.i�t��. Y� ; ; ....... ,..�.......................�...,.......................r: caied.#�C:is:sama. rlaa::a��i�: <;:>:>: .................�.....�:.:::::•::•::.:••><»>::»>;:::.:::F�r:�ut��rt n�s�:::�A. . e::o�.d:. cx!asc�ass med:.JFss��:: ....... Access Road, R/D $ 16.74 SY Bollards-fixed $ 240.74 Each Bollards-removable $ 452.34 Each • CBs include frame and lid CB T e I $ 1,257.64 Each CB T e IL $ 1 433.59 Each CB T e II 48'diameter $ 2 033.57 Each for additional de th over 4' $ 436.52 FT CB T e II 54'diameter $ 2,192.54 Each for additional de th over 4' $ 486.53 FT CB T II 60`diameter $ 2 351.52 Each for additio�al de th over 4' $ 536.54 FT CB T II 72'diameter $ 3 212.64 Each for additional de th over 4' $ 692.21 FT Throu h-curb Inlet Framework Add $ 366.09 Each Cleanout, PVC,4' $ 130.55 Each Cleanout, PVC 6' $ 174.90 Each Cleanout PVC,8' $ 224.19 Each Culvert PVC 4' $ 8.64 LF Culvert PVC,6' $ 12.60 LF Culvert PVC, S" $ 13.33 LF cuivert,Pvc, i2• $ 2�.n LF Culvert,CMP,8' $ 17.25 LF Culve�t,CMP 12" $ 26.45 LF Culvert,CMP 15' $ 32.73 LF Culvert CMP 18' $ 37.74 LF Culvert CMP,24' $ 53.33 LF Culvert,CMP,30' $ 71.45 LF Culvert,CMP,36' $ 112.11 LF Culvert CMP,48' $ 140.83 LF Culvert CMP,60` $ 235.45 LF Culvert,CMP,72' $ 302.58 LF Page 6 of 9 SUBTOTAL Unit prices updated: 02/12/02 'KCC 27A authorizes oniy one bond reduction. VefSlon: 4/22/02 af.557.x1s Report Date: 9/27/2002 Site Improvement Bo �uantity Worksheet _ < ; Exisdng >::.�ulurc:�'u�i� .: Priv�a�a �na�i�ctuctio��' ; , , ; ,: >' ,::. , Right-AT-way;; iiO�td hnpruY�ilit�Eli� Im{�a`oventent8 :! _ G C , ; > _. ; ' &prataags�acllNies;::. Qu��t, '' L1nit Prir.,ei ::: Unii< Q�a.a.:rit. : �e�st: C}ua�st; �aSt.:; Q�aant.: <Cc�si : �a�n efe C,�st Culvert,Concrete 8' $ 21.02 LF Culvert Concrete, 12' $ 30.05 LF Culvert,Concrete 15' $ 37.34 LF Culvert Concrete 18' $ 44.51 LF Culvert,Concrete 24' $ 61.07 LF Culvert Concrete,30' $ 104.18 LF Culvert Concrete 36" $ 137.63 LF Culvert Concrete 42' $ 158.42 LF Culvert,Concrete 48" $ 175.94 LF Culvert,CPP 6' $ 10.70 LF Culvert,CPP 8' $ 16.10 LF Culvert CPP 12' $ 20.70 LF Culvert CPP, 15' $ 23.00 LF Culvert CPP, 18" $ 27.60 LF Culvert,CPP,24' $ 36.80 LF Culvert,CPP 30' $ 48.30 LF Culvert CPP 36' $ 55.20 LF Ditchin $ 8.08 CY Flow Dis ersal Trench 1 436 base+ $ 25.99 LF French Drain 3'de th $ 22.60 LF Geotextile,laid in trench, ol ro lene $ 2.40 SY Infiltratlon ond testin $ 74.75 HR Mid-tank Access Riser 48'dia, 6'dee $ 1 605.40 Each Pond Overflow S illwa $ 14.01 SY RestrictodOil Se arator,12' $ 1 045.19 Each Restrictor/Oil Se arator 15" $ 1,095.56 Each Restrictor/Oil Se arator,18' $ 1,146.16 Each Ri ra , laced $ 39.08 CY Tank End Reducer 36'diameter $ 1,000.50 Each Trash Rack, 12" $ 211.97 Each Trash Rack 15" $ 237.27 Each Trash Rack, 18' $ 268.89 Each Trash Rack,21' $ 306.84 Each Page 7 of 9 SUBTOTAL Unit prices updated: 02/12/02 'KCC 27A authorizes onty one bond reducGon. Verslon: 4/22/02 af.557.x1s Report Date: 9/27/2002 Site Improvement Bo Quantity Worksheet ; ' ' < <:: �x►g�ru3 ;; ; F��st�;Pk�b�1R..< £'rivi�e �ond ti�ctuction' : . ;, '' , ' ' F�ighc-oi-►vny; iioad Iinpro��n�ciis� ;Imprc►usmeats ': ';: >:;>:: . ' ; ;: i ' _.I....�r.DraiRa e�'acilitlbs'<: _IQ�raat..: _ _ `::.. '. . ` ` ' Unit Price E3nit< Q�aaRt :::.. Pride Qu�nt �a�!':' QuaR4-:;: �s�st :' �am ef�i '�st 2'AC 2'to course rock&4'borrow $ 15.84 SY 2'AC 1.5' to course& 2.5'base course $ 17.24 SY 4'select borrow $ 4.55 SY 1.5'to course rock&2.5"base course $ 11.41 SY V1/Ft1'i'E=11V-i'�`EIVtS .:...:. ` ,' ` ' EA. EA. LF EA. EA. EA. LF SF LF �F SUBTOTAL SUBTOTAL(SUM ALL PAGES): 30%CONTINGENCY&MOBILIZATION: GRANDTOTAL: COLUMN: B C D E Page 8 of 9 Unit prices updated: 02/12/02 "KCC 27A authorizes only one bond reduction. Vefslon: 4/22/02 af.557.x1s Report Date: 9/27/2002 5ite Improvement Bond Quantity Vvorksheet �putations prepared by: Date: amber: Tel.#: Project No: ROAD IMPROVEMENTS&DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND' PUBLIC ROAD&DRAINAGE AMOUNT BOND'AMOUNT MAINTENANCE/OEFECT BOND' REQUIRED AT RECORDING OR ion Sediment Control (ESC) (A) $ - TEMPORARY OCCUPANCY"' Way Improvements (B) $ - �d Improvements&Drainage Facilities (C) $ - ients (D) $ - ity Completed (E) $ - �y and/or Site Restoration Bond'/" (A+B) $ - (First$7,500 of bond'shall be cash.) id'Amount (A+B+C+D) = TOTAL (T) $ - T x 0.30 $ - OR I rnmum n amount s . iance Bond*Total""' (T-E) $ - Use larger o x o or - (g+C)x ect Bond`Total 0.25= $ - V PREPARING BOND'REDUCTION: Date: �word'bond"as used in this document means any financial guarantee acceptable to King County. I C 27A authorizes right of way and site restoration bonds to be combined when both are required. �restoration requirement shall include the total cost for all TESC as a minimum,not a maximum. In addition,corrective work,both on-and off-site needs to be included. �ntities shall reflect worse case scenarios not just minimum requirements. For example,if a salmonid stream may be damaged,some estimated costs for restoration �s to be reflected in this amount. The 30%contingency and mobilization costs are computed In this quantiry. KCC 27A,total bond amounts remaining after reduction shall not be less than 30%of the original amount(T)or as revised b ma or design changes. REfY BOND RIDER NOTE: If a bond rider is used,minimum add'Rional performance bond shall be $ - (C+D)-E 'AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DDES Unit prices updated: 02/12/02 Version: 4/22/02 Report Date: 9/27/2002 1 Site Improvement Bor�d Quantity Worksheet Original bond computations prepared by: I�, Name: Date: I PE Registretion Number: Tel.#: j Firm Name: '' Address: Project No: ROAD IMPROVEMENTS 8 DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND' PUBLIC ROAD&DRAINAGE AMOUNT BOND'AMOUNT MAINTENANCE/DEFECT BOND' REQUIRED AT RECORDING OR Stabilization/Erosion Sediment Control (ESC) (A) $ - TEMPORARY OCCUPANCY"' Existing Right-of-Way Improvements (B) $ - Future Public Road Improvements& Drainage Facilities (C) $ - Private Improvements (D) $ - Calculated Quantity Completed (E) $ - Total Right-of Way and/or Site Restoration Bond"/"" (A+B) $ - (First$7,500 of bond'shall be cash.) Performance Bond'Amount (A+g+�+D) = TOTAL (� $ - T x 0.30 $ - OR inimum on amount is . Reduced Performance Bond*Total**" (T-E) $ - Use larger o x o or - (g+C)x Maintenance/Defect Bond`Total 0.25= $ - NAME OF PERSON PREPARING BOND"REDUCTION: Date: 'NOTE: The word"bond"as used in this document means any financial guarantee acceptable to King County. ""NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required. The restoration requirement shall include the total cost for all TESC as a minimum, not a maximum. In addition,corrective work,both on-and off-site needs to be included. Quantities shall reflect worse case scenarios not just minimum requirements. For example, if a salmonid stream may be damaged,some estimated costs for restoration needs to be reflected in this amount. The 30%contingency and mobilization costs are computed in this quantity. '•"NOTE: Per KCC 27A,total bond amounts remaining after reduction shall not be less than 30%of the original amount(T)or as revised by major design changes. SURETY BOND RIDER NOTE: If a bond rider is used, minimum additional performance bond shall be $ - (C+D)-E REQUIRED BOND"AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DDES Page 9 of 9 Unit prices updated: 02/12/02 Version: 4/22/02 af.557.x1s Report Date: 9/27/2002 KING COUNTY,WASHINGTON,SURFACE WATER DESIGN MANU: STORMWATER FACILITY SUMMARY SHEET Development Date Location ENGINEER DEVELOPER Name Name Firm Firm Address Address Phone Phone Developed Site: Acres Number of lots Number of detention facilities on site: Number of infiltration facilities on site: ponds ponds vaults vaults tanks tanks Flow control provided in regional facility(give location) No flow co�trol required Exemption number Downstream Draina e Basins Immediate Ma'or Basin Basin A Basin B Basin C Basin D Number&type of water quality facilities on site: biofiltration swale(regular/wed or sand filter(basic or large?) continuous inflow?) sand filter,lineaz(basic or large?) combined detention/WQ pond sand filter vault(basic or large?) (WQ portion basic or lazge?) combined detention/wetvault stormwater wedand compost filter wetpond(basic or large?) filter strip wetvault flow dispersion farm management plan landscape management plan oiUwater separator(baffle or coalescing plate?) catch basin inserts: Manufacturer pre-settling pond pre-settling structure; Manufacturer flow-spIitter catchbasin DESIGN INFORMATION INDIVIDUAL BASIN A B C D Water uali desi flow Water ualit treated volume or wet ond Vr 1998 Surface Water Design Manual 9/1/98 1 AF.675 KING COUNTY,WASHINGTON,SURFACE WATER DESIGN MANUAL DESIGN TOTAL INDIVIDUAL BASIN INFORMATION,cont'd Drainage basin(s) A B C D Onsite area Offsite Area T e of Stora e Facilit Live Stora e Volume Predevelo d Runoff Rate 2- ear 10- ear 100- ear Develo ed runoff rate 2- eaz 10- ear 100- ear T of restrictor Size of orifice/restrictor No. 1 No.2 No. 3 No.4 FLOW CONTROL&WATER QUALITY FACII.ITY SUMMARY SHEET SKETCH All detention,infiltration and water quality facilities must include a sketch per the following criteria: 1. Heading for the drawings should be located at the top of the sketch(top right-hand cornerl. The heading should contain: • North arrow(point up or to left) • D9# • Plat name or short plat number • Address(neare;c i • Date drawn(or updated) • Thomas Brothers pa�:c, grid numher 2. Labe(CBs and M�-�s with the plan and profile designation. Label the control structure in ��riri��_� e�r ahnr��,i.�te �cith C.S. Indicate« 3. Pipes—indicate Pipe size Pipe length Flow directwu Use a single heavy weight line 4. Tanks--use a double,heavy weight line and indicate size(diameter) 5. Access roads • Outline the limits of the road • Fill the outline with dots if the road is gra�el. Label in writing if another surface. 6. Other Standazd Symbols: • Bollards �� ■■■■ • Rip rap°000000 Fences --x--x—x—x—x—x-- • Ditches—D---►D---�D 7. Label trash racks in writing. 8. Label all streets with the actual street sign designation. If you don't know the actual street name,consult the plat map. 9. Include easements and lot lines or tract limits when possible. 10. Arrange all the labeling or writing to read from left to right or from bottom to top with reference to a pmperly oriented heading. 11. Indicate driveways or features that may impact access,maintenance or replacement. 1998 Surface Water Design Manual 9/1198 � 2 AF.675 i ' � ' i-ez�m='�-ezio�z �w�x.••000 or-� :non ecu rooz/ro/zo �wu/•�ro 6»v�x-esioi\6u��i6�•\ez�oi\w000i\e •i� 1`�ld J�lOM6 NO�L�`ldb'Y�I ZIZQ�(�3WEld�i�l �rr,•o ��n�oi.aiwo�a.�s .,aN,�"��N,., l l SrU8a VM'3LL1V3B :;� �r-.�w �•Nrti aMn roNm�ao�,a .�a '�.s 3N 3AV ld1.B OlaB ,�� -��•.•o xv� zoco-►sz(sz►� � � ,•• dVW�l�tl 3�NV�13M10� � i�cw�� i s�.�� "'•,"' �,�—,..,, zc°°ervM �� <� �Ml � � �-�..�,., Hu�os �v arac s�zo� � 4ZIOl �++w ,o ,•d .M •.•�.r 1 I ' 1 I I I ,� - �_ - �� \ �� - _ I �� /'!� ��°�$� ^ I ,, ,, - _� W� I � �` ( i ; `� � , ; � 8 ', � y !. ` .r , 4i G> � 9 , �S. � 8� / ,,`�'� 1 1 � $� •�/ k , , � 1 � I 1 �t � irui-.. ,✓`vL� f� r i r - . � ...na.., � , � ,� ._....>.:. . r�; Q I `� �i� ��• '� ,� ._r'` / , 1� � I ,` i' / �..,� �- L�., "" /' /i'� w. V'`Ti. � W ,/� / `, �S � i 1 • � -� i , �� A �%`�$ �z ; ��, '°r� _�� r---�-� ,�� i �'� ' U � � •� .,- _;........ ��'�- ��1�: �.. �. , i , � $y�� g �� %.� . ", w.u-' .' � ,_ � � r I Z � ki t �l � i' /a`. //� Ay � ( �'` e ��/ _ •y' '"� ^� F� / Bd A . �' .., !M/ K - �' ;t �, i �• ., ,: /�' ;. . i' ^n' Q . �. •5.�y„ .�' � r�. �� ,. 1 �� . - �... ,� �x ' �.+ :� . �� 'a. _.-ra, � �b \ \ .. �.( ,.,� .i acE" � � \./' � .:� _r�.,,, r y f �- � \ �..� �'_� � �i `�9r� tSY,� W <5 \ ..'. .�'i , __'� '"Ji� k '� r^..- f.: \� � _� �'�-I�.,.I I �• �' � � � ��;,.. �...''�_,"�', 1 �� .�,�'�.-��""' � � ' --- ', �--- ---�'--- -- ' � �' � � ��,�� .�..::.,. Z �� : f - • ,�-�- �!; / �„Jj 3 . �' .�,�a...Y' _.�. j�. .. . � �� ii ao O �,,... '��- �i : 'i ,f '� �_• m � � � �g� s (�� , r �:, I. � e k ��s a ..1\` .' �� #'.� ' �•�'� af' � $ � �� I � ��R�� U �, � � � ,'J�t{,. :•- � � � �g � r�Bt � \�, , Y '�' � � /�r' R�� ' ��b ��. ...�.... � . � � .- .� , a�. � �\�j\,�.., r�� :s• > � � % �:o. � « I' �,�` � �....� �. �, i �.^�,, :, ----- ` E.., g �~�. .._ �� "�� _---�"� M �\'c�,,; ...�,....Y 4. � : att.vTt,a�-• _ _ _ _ "_.;w •-�e�^` N� �.6� ��y.. �+p0�'�E�r'r"r-- �� `,�J ' � � � �, = r. -- ��• - - - y g'�.\',�i �'' ' � -�.\� . �'`�..�. � +,�C'��._ �3: � \�'�� ° �J�.i�� .* �;%,e:�'..,� �� ■ i - - ' -- �°.G ` / J �n� ��.r,',"� \Gr' �b�`� l._...... / ' ` ;s::. ' s o�...,i � .�`'�� '�� k � �x�� ``. � -� � , �r�: �� ,� �'": i � `',� • ��'° , ' ��J � f ��s �� >^- �� x�, aa�e �a &�8 � � w�v °ue '`.. ��-�,.� �,s .�� i� �� /,. � 1G,��,.,xls BARGHAUSEN CONSULTING ENGINEERS-PIPE FLOW CALCULATOR � using the Rational Method&Manning Formula i KING COUMY DESIGN FOR 25 YEAR STORM JOB NAME: MAPLETON NOTE:EMER DEFAULTS AND STORM DATA BEFORE BEGINNING I JOB#; 10128 DEFAULTS C= 0.6 n= 0.014 REVISED: 2/3/2003 d= 8 7c= 6.3 A=Contributing Area(Ac) 9d=Design Flow(cfs) COEFFICIENTS FOR THE RATIONAL METHOD"Ir"-EQUATION I C=Runoff Ccefficient 9f=Full Capacity Flow(cfs) STORM Ar Br ' Tc=Time of Concentration<min) Vd=Veloclty at Deslgn Flow(fps) 2VR 1.58 0.58 1=Intensity at Tc Qn/hr) Vf=Velocity at Full Flow(fps) lOYR 2.44 0.64 PRECIP= 3.4 d=Diameter of Pipe(In) s=Slope of plpe(96) 25YR 2.66 0.65 Ar= 2.66 L=Length of Pipe(ff) n=Manning Roughness Coefficient 50YR 2.75 0.65 Br= 0.65 D=Water Depth at Qd(in) Tt=Trrnel Time at Vd(min) 100YR 2.61 0.63 FROM TO A s L d Tc n C SUM A A'C SUM A'C I 9d Qf Ad/Af D/d D Vf Vd Tt I CBb C85 0.54 0.66 35 8 10.0 0.014 0.5 0.54 0,27 0.27 2.02 0.55 0.91 0.600 0.557 4.46 2.61 2.72 0.21 CB5 C84 0.12 7.58 55 8 10.2 0.014 0.6 0.66 0.07 0.34 2.00 0.68 3.09 0.221 0.317 2.54 8.85 7.09 0.13 CB4 C83 0.17 13.73 63 8 10.3 0.014 0.6 0.83 0.10 0.44 1.98 0.88 4.16 0.212 0.309 2.47 11.92 9.40 0.11 CB3 CB2 0.12 0.50 18 12 10.5 0.014 0,6 0.95 0,07 0,52 1.97 1.01 2,34 0.434 0.462 5.55 2.98 2.90 0.10 C82 CB1 0.07 3.18 38 8 10.6 0,014 0.9 1.02 0.06 0.58 1.95 1.13 2.00 0.566 0.538 4.30 5.74 5.90 0.11 CB3A CB1 A 0.77 3.13 48 8 10.0 0,014 0,5 0.77 0.39 0.39 2,02 0.78 1.98 0.393 0.435 3.48 5.69 5.35 0,15 ', CB1A CB1B 0.08 26.70 15 8 10.1 0.014 0.3 0,85 0.02 0.99 2,01 1.98 5.80 0.342 0.404 3,23 16.62 15.10 0.02 CBl B EX CB 0.00 18.57 7 8 10.2 0.014 0,6 0,85 0.00 0.99 2.00 1.98 4.83 0.409 0.446 3.57 13.86 13.21 0.01 CB1C EXCB 0.04 5,00 7 8 6.3 0.014 0.9 0.04 0,04 0.04 2.73 0.10 2.51 0.039 0.139 1.11 7.19 3.47 0.03 Page 1 l Ol__ ._J.xis BARGHAUSEN CONSULTING ENGINEERS-PIPE FLOW CALCULATOR using ihe Rational Method&Manning Formula KING COUNTY DESIGN FOR 100 YEAR STORM JOB NAME: MAPLETON NOTE:ENTER DEFAULTS AND STORM DATA BEFORE BEGINNING JOB#: 10128 DEFAULTS C= 0.6 n= 0.014 REVISED; 2/3/2003 d= 8 Tc= 6.3 A=Contributing Area(Ac) 9d=Design Flow(cfs) COEFFICIENTS FOR THE RATIONAL METHOD"Ir"-E9UATION C=Runoff Coefflcient 9f-Full Capacity Flow(cfs) STORM Ar Br Tc=Time of Concentration<min) Vd=Velocity at Design Flow(fps) 2YR 1.58 0.58 � 1=Intensity at Tc(in/hr) Vf=Velocity at Full Flow(fps) lOYR 2.44 0.64 PRECIP= 3.9 d=Dlameter of Pipe(in) s=Slope of pipe(%) 25YR 2.66 0,65 Ar= 2.61 L=Length of Pipe(ff) n=Monning Roughness Coefflclent 50YR 2.75 0,65 Br= 0.63 I D=Water Depih ot 9d pn) Tt=Travel Tfine at Vd(min) 100YR 2.61 0.63 FROM TO A s L d Tc n C SUM A A"C SUM A'C I Qd 9f Ad/Af D/d D Vf Vd Tt CB6 C85 0.54 0.66 35 8 10.0 0.014 0.5 0.54 0.27 0.27 2.39 0.64 0.91 0.707 0,621 4.97 2.61 2.84 0.21 CB5 C64 0.12 7.58 55 8 10.2 0.014 0.6 0.66 0.07 0.34 2.36 0.81 3.09 0.261 0,349 2.79 8.85 7.45 0.12 CB4 CB3 0.17 13.73 63 8 10.3 0.014 0.6 0.83 0.10 0.44 2.34 1.04 4.16 0.250 0.340 2.72 11.92 9.89 0,11 C63 CB2 0,12 0.50 18 12 10.4 0.014 0.6 0.95 0.07 0.52 2.32 1.20 2.34 0.513 0,507 6.09 2.98 3.01 0,10 CB2 CB1 0,07 3.18 38 8 10.5 0.014 0.9 1.02 0.06 0.58 2,31 1.34 2.00 0.668 0.598 4.78 5.74 6.13 0.10 CB3A CB1A 0.77 3.13 48 8 10.0 0.014 0.5 0.77 0.39 0.39 2.39 0.92 1.98 0.463 0,479 3.83 5.69 5.63 0.14 CB1A CB18 0.08 26.70 15 8 10.1 0.014 0.3 0.85 0.02 0.99 2.37 2,34 5.80 0.403 0,442 3.54 16.62 15.75 0.02 CB1 B EX CB 0.00 18.57 7 8 10.2 0.014 0.6 0.85 0.00 0.99 2.36 2.33 4.83 0.483 0,490 3.92 13.86 13.83 0.01 C61 C EX CB 0.04 5.00 7 8 6.3 0.014 0.9 0.04 0.04 0.04 3,19 0.11 2,51 0.046 0.148 1.18 7.19 3.61 0.03 Page 1 ' 02i2��200� 13:56 F�S 425 251 8782 BARGA�L'SEN . �OO1i004 ��.��5�2 CNit ENGtNeERING,LANC FLANNING,SURVEVING,ENVIRONMtnTA�S nVICES �' � � DATE: February 24, 20Q3 -�i ��,,��'�� TOTAL PAGES (including cover sheet): 4 FACS I M I LE: 425-430-7241 TO: Alla� Quinn City o` Renton FROM: Hal Grubb RE: Map{eton Short Piat JO$ NO: 10126 MESSAGF� ', Alla� Here are tr,e capacity calculations for tne conveyance ditch as well as the nydro;ogy for tre upstream basin. Please review and let me know if you have any questions. Thanks cc: Fax No: Fax No: Fax No: Fax No: Please eal!{425j 251-6222 if you do not receive the indicafed nLmber of pages. 1P215 72VD AVENJE S�I;TH �CEN?.4'YA 9d032 (a25)251-b222 ;42�j 251-8702 FAX p2i24i2003 13:�6 FAT �25 251 8782 BARGHaUSEN _ , �002/004 : Feb 24 03 D1 : 17p IS Dept 3607059796 P - � �Gb �`� Go�V�f�h'� ��ZG. BYPASS DITCH FOR UPSTREAM FLOW Workshee#for Triangular Channel Project Description Project File c:lhaestad\fmw\10128-bi.fm2 Wo�ksheet BYPASS D{TCH Flow Element Triangular Channel Method Manning's Formula Solve �or GhanneJ Depth Input Data Mannings Coefficient 0.030 Channe!Slope 4.030000 ft/ft �-�----- �SV�� S� �� I Left Side Slope 2_000000 H :V Right 5ide Slope 2.QOQODO H ; V Oischarge 0.50 cfs 1 (Op� �*-iG '�� I Resulls Depth 0_32 ft r'�'"'— � ��50 �� I Flow Area 0.21 f� I Wetted Perimeter 1.45 ft Top Width 1.30 ft � � � Critical Depth 0.33 ft Criti�a�Slope 0.027757 ftlft Velocity 2,37 ffls Velocity Head 0.09 ft Specific Energy 0.41 ft Froude fVumber 1.04 Ffow is supercritical. I � � 0?l24/03 FlowMas[er v5.15 11:55ia4AM HaeSt�C MOthod3,Ina 37 Brookside Road WaterSury, CT06708 (2�3)755-]666 Page 'I o�'� 02i24/2003 1�:56 FAT �25 251 8782 BaRGHAL5E1 _ �003i00� � � 3E07059796 p � � . Feb 24 03 O1 _ 1Sp I5 Dept � �Ol Z� � —r n��. �� s �r r�.: I01Z8-BYP.exC KCRTS program. . . File Directo�y; C:\KC_�WDM\K�.DATA\ [C� CRCATE a new Time SerieS ST 0.00 0.00 0.000000 Till Forest � 0,53 0.00 0.000000 Till Pasture � 0.0� 0_00 0.000000 Till Grass 0.00 0.00 0.000000 outwash �orest 0.00 0,00 0.000000 outwash Pasture 0.00 0.00 0.000000 Outwash Grass O.Oo 0_00 0.000000 wetland —�0.32 0.00 0.000000 zmpervious E— UPSTREAM.ZSf T � 1.00000 F [T] Enter the Analysis TOOLS Module [P] Compute PEAKS and F'ow FrequenCies upstream.tsf UPSTREAM.pks [R] RETURN to Previous ,Menu [X] eXit KCRTS Program � ��1- ��i�-�t�v►�1 �l� �a� =. p, �S� ,4rssu�n� 3.5 a�/�c. � 3gi. l,nnpv . � Poe�-= o.�3 � ( M.F�U . �� 0,3 Z� Page 1 p2�2�'2003 1�:57 F�1 d2� 2�1 8782 BaRGA�LSE\ .. �oo��ooa .• Feb 24 03 01 : 18p IS DepL 3607059796 P - 4 .. ,, . lSt� �S t nl - �'�-��. ti.�w S Cw f ��M,N T�s�� Flow Frequer.cy Analysis Time Series File:Lpstream_tsf Froject Location:5ea-Tac ---Ar.nual Peak Flow Ra�es--- -----F1ow F=cquency Analysis------- Flo�r Rate Rank Tine of Peak - - Peaks - - Rank Return Prob (CFS) . (CFS} ?eriod 0_153 6 6/27/O1 18:00 �-� 0.488�- 1 100.00 0. 990 0_112 8 1105/02 �5:00 0.354 2 25.OD 0. 90'0 0.354 2 12/08/C2 17:15 0.209 3 10.00 0. 9CC 0.123 7 8/23/04 19:30 0.181 4 5.00 0, 80C 0.172 5 �0/28/04 16:00 0.172 � 3.00 0. 60'7 0. 181 9 10/27/OS 10:95 0.153 6 2.00 0.50G 0.209 3 1C/25/06 2�;45 0.123 ' 7 1.30 0.231 G. 4fi8 1 1/09/06 6c30 0.'�12 � ' B 1.10 0. 091 �omputed Peaks 0.443 50.00 0. 990 �