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HomeMy WebLinkAbout03814 - Technical Information Report �� l.�(� u�G 3� � � �� �� �- ` � m TECHNICAL INFORMATION REPORT ' Plat of Copperwood (a.k.a. Stuth Property) Renton, Washington Prepared for: , The Quadrant Corporation ' 14725 S.E. 36th Street, Suite 200 , Bellevue, WA 98006 Revised April 29, 2015 ' Revised April 7, 2015 Revised February 13, 2015 December 2, 2014 Our Job No. 16834 !, �y J. T A �� ' �P��a� w a �y �� � , � z � o N Z 0 41423 Q �� �F ��STE��' ��, GHAV �s�NA L ��1G� 4 �►� s� 04/29/15 � 1� ? 18215 72ND AVENUE SOUTH KENT,WA 98032 (425)251-6222 (425)251-8782 FAX ° ` ? BRANCH OFFICES • TUMWATER,WA ♦ LONG BEACH,CA ♦ ROSEVILLE,CA ♦ SAN DIEGO,CA 0 �� y� www.barghausen.com <r�N ��4 I C ENG�N ( 3 8/� TABLE OF CONTENTS 1.0 PROJECT OVERVIEW Figure 1 —TIR Worksheet Figure 2—Site Location Figure 3— Drainage Basins, Subbasins, and Site Characteristics Figure 4—Soils ' Figure 5— FEMA Map Figure 6—Sensitive Areas Map 2.0 CONDITIONS AND REQUIREMENTS SUMMARY 2.1 Analysis of the Core Requirements 2.2 Analysis of the Special Requirements 2.3 Hearing Examiner Conditions 2.4 SEPA Conditions 3.0 OFF-SITE ANALYSIS 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN A. Existing Site Hydrology B. Developed Site Hydrolagy C. Performance Standards D. Flow Control System E. Water Quality System 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN 6.0 SPECIAL REPORTS AND STUDIES 7.0 OTHER PERMITS 7.1 Postmaster/ Mailbox Locations Approval 7.2 Hydraulic Project Approval 7.3 NPDES Permit 8.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN (CSWPPP) ANALYSIS AND DESIGN 9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECI.ARATION OF COVENANT 9.1 Bond Quantities 9.2 Facility Summary Form 9.3 Declaration of Covenant for Impervious Surface Limit ' 16834.015.doc 9.4 Declaration of Covenant for Inspection and Maintenance of Stormwater Facilites and BMPS 10.0 OPERATIONS AND MAINTENANCE MANUAL APPENDIX APPENDIX A- Lower Cedar River Basin and Nonpoint Pollution Action Plan APPENDIX B- Downstream Drainage Complaints 16834.015.doc 1.0 PROJECT OVERVIEW The proposed Plat of Copperwood is a single-family residential project consisting of 47 lots zoned R4, and will be utilizing the small lot clustering provisions. The project is 12.68 acres in size, containing 8 tax parcels (152305-9066, 152305-9067, 152305-9201, 152305-9100, 152305-9093, 152305-9170, 152305-9043, and 152305-9221). The site is located at the intersection of 143rd ' Avenue S.E. and S.E. 2nd Place, in a portion of Section 15, Township 23 North, Range 5 East, W.M., in the City of Renton. The site is rectangular in shape and fronts S.E. 2nd Place. The proposed on-site roads are to be tied into S.E. 2nd P�ace, and will be extended into the site to provide public access and circulation. This site is currently developed, with seven single-family residences and is currently zoned R4. The existing on-site improvements consist of storm and water utilities, and gravel , driveways that access S.E. 2nd Place. There is a creek on-site (Maplewood Creek Tributary 0303), near the east property line. The existing site drains to Maplewood Creek Tributary 0303, ' where it then leaves the site near the southeast comer. The existing discharge point is to be maintained after development. The site is bound along the east property line by 143rd Avenue S.E. To the south and west the site is bound by single-family residences. The southeast corner of the site contains steep slopes ranging from 15 percent to 70 percent. These steep slopes will be contained within a Natural Growth Protection Area (NGPA) Tract. On the north side of the site is bound by S.E. 2nd Place. Accessing the site from S.E. 2nd Place will require frontage improvements, including new asphalt and new curb and gutter, with sidewalk and planter strip. On-site soils are mapped as Alderwood. Please refer to the Figure 4 — Soils Map within this section. All drainage calculations were modeled as till soils. The project will be constructing new roadways consisting of curb and gutter, sidewalk, and street trees. The site will tie into the existing road at S.E. 2nd Place. All roads for this project have oeen designed '[v oe �o ieei wide, wiiii aii o-iuvi �iaiiiei 3iiiN ai iiic back of curb and a 5-foot sidewalk on both sides. The overall proposed public right-of-way will be 53 feet in width. The on-site topography is generally flat, with a slight hill in the westernmost portion of the site. The site generally slopes from west to east, toward Maplewood Creek Tributary 0303, from elevation 398 to 386. The project will be mass graded with cuts and fills balanced on site. The ' proposed development also includes further restoration of the Maplewood Creek Tributary 0303 buffer area. The drainage facilities are required to meet the requirements of the 2009 King County Surface Water Design Manual (KCSWDM), and the 2010 City of Renton Amendments to the KCSWDM. The drainage design shall meet, at a minimum, the Flow Control Duration Standard Matching Forested Site Conditions and will provide Enhanced Basic Water Quality Treatment. The drainage facility located in Tract B is a combination detention/wet pond. The wet pond will be sized pursuant to the 2009 KCSWDM and the City's amendments to ensure that the Basic Water Qualiry requirement is met. To provide Enhanced Basic Water Quality a paired water quality treatment train will be used, with the first water quality facility being the previously described wet pond. The second water quality facility will be a StormFllter Vault using CSF media located downstream of the wet pond's flow control structure. The project will be discharging the drainage from the pond to Maplewood Creek Tributary 0303. Please refer to Section 4.0 for detailed drainage calculations. 16834.015.doc i �--� � � � � � r O � � � � � .� �..L � K1NG COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL , TECHNICAL INFORMATION REPORT TIR WORKSHEET I�i � � I Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND PROJECT ENGINEER DESCRIPTION Project Owner The Ouadrant Cor�oration Project Name Plat of Conver���ood Phone DDES Permit# Address 14725 SE 36� Street, Suite 100 Location Township 23N Bellevue. WA 98006 Range SE Project Engineer Barry Talkington, P.E. Section 15 Company Bar�hausen Consultin� En�ineers, Inc. Site Address Renton,WA Phone (42�) 251-6222 Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS '- � Landuse Services ❑ DFW HPA ❑ Shoreline Subdivision / Short Subd. / UPD ❑ COE 404 Management � ❑ Building Services ❑ DOE Dam Safety � Structural M/F /Commercial / SFR RockeryNault/ � Clearing and Grading ❑ FEMA Floodplain ❑ ESA Section 7 � Right-of-Way Use ❑ COE Wetlands ❑ Other ❑ Other Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review Full / Targeted / Type(circle one): Ful / Modified I (circle): Large Site Small Site Date (include revision Februarv 13, 2015 Date (include revision February 13,2015 dates): Agril 7.2015 dates): April 7. 2015 Date of Final: A ril 29 2015 Date of Final: A ril 29. 2015 Part 6 ADJUSTMENT APPROVALS , Type (circle one): Standard / Complex / Preapplication / Experimental / Blanket Description: (include conditions in TIR Section 2) Date of Approval: 2009 Surface Water Design Manual 1/1!09 1 16834.016-FINL TIR Worksheet.doc KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 7 MONITORING REQUIREMENTS ' Monitoring Required: Yes / No Describe: Start Date: Completion Date: Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan : Special District Overlays: Drainage Basin: Lower Cedar River Basin Stormwater Requirements: Flow Control Duration Standard Matchin�Forested Site Conditions Part 9 ONSITE AND ADJACENT SENSITIVE AREAS � River/Stream � Steep Slope ❑ Lake ❑ Erosion Hazard ❑ Wetlands ❑ Landslide Hazard ❑ Closed Depression ❑ Coal Mine Hazard ❑ Floodplain ❑ Seismic Hazard ❑ Other ❑ Habitat Protection ❑ Part 10 SOILS Soil Type Slopes Erosion Potential i AeC 6-15 Percent Hi�h ❑ High Groundwater Table (within 5 feet) ❑ Sole Source Aquifer ❑ Other ❑ Seeps/Springs ❑ Additional Sheets Attached 2009 Surface Water Design Manual 1/1/09 2 16834.016-FINL TIR Worksheet.doc KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 11 DRAINAGE DESIGN LIMITATIONS � REFERENCE LIMITATION /SITE CONSTRAINT ❑ Core 2—Offsite Analysis ❑ Sensitive/Critical Areas ❑ SEPA ❑ Other ❑ ❑ Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) ' Threshold Discharge Area: name or descri tion Dischar e to Ma lewood Creek Tributa 0303 near southeast corner of site. Core Requirements (all 8 apply) Dischar e at Natural Location Number of Natural Dischar e Locations: 1 Offsite Analysis Level: 1 / / 3 dated: February 13, 2015 Flow Control Level: 1 / / 3 or Exemption Number (incl. facility summary sheet) Small Site BMPs Conveyance System Spill containment located at: N/A Erosion and Sediment Control ESC Site Supervisor: TBD , Contact Phone: TBD ' After Hours Phone: TBD Maintenance and Operation Responsibility: Private / Publi ' If Private, Maintenance Lo Re uired: Yes / No Financial Guarantees and Provided: Yes / No Liabilit Water Quality Type: Basic / Sens. Lake / Enhanced Basic / Bog (include facility summary sheet) or Exemption Na ', Landsca e Mana ement Plan: Yes / N Special Requirements (as applicable) Area Specific Drainage Type: CDA/SDO/ MDP/BP/LMP/Shared Fac. / Non Requirements Name: Floodplain/Floodway Delineation Type: Major / Minor / Exemption / Non , 100-year Base Blood Elevation (or range): � Datum: Flood Protection Facilities Describe: N/A Source Control Describe landuse: N/A (comm./industrial landuse) Describe any structural controls: N/A 2009 Surface Water Desien �4anual 1/1/09 y 3 16834.016-FINL TIR Vb'orksheet.doc KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Oil Control High-use Site: Yes / N Treatment BMP: Maintenance Agreement: Yes / N� with whom? Other Drainage Structures ' Describe: Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION � Clearing Limits � Stabilize Exposed Surfaces � Cover Measures � Remove and Restore Temporary ESC Facilities � Perimeter Protection � Clean and Remove All Silt and Debris Ensure ❑ Traffic Area Stabilization Operation of Permanent Facilities � Sediment Retention � Flag Limits of SAO and open space preservation areas � Surface Water Control ❑ Other ❑ Dewatering Control � Dust Control � Flow Control Part 14 STORMWATER FACILITY DESCRIPTIONS Note: Include Facilit Summa and Sketch Flow Control T e/Descri tion Water Quali T e/Descri tion � Detention Pond ❑ Biofiltration ', ❑ tnfiltration � Wetpool Wetpond ❑ Regional Facility � Media Filtration StormFilter ❑ Shared Facility ❑ Oil Control ❑ Flow Control ❑ Spill Control BMPs ❑ Flow Control BMPs ❑ Other ❑ Other 2009 Surface Water Design Manual l/1/09 4 16834.016-FINL TIR Worksheet.doc � 0 -1--+ � N U � O L � � � � -�-� �..L V J �.e�cn� a � � � g Ne Sth St � � �� � � S 0 � � ,� ; ae a�i Windior ,� � � Hills Park F`"'d �,an s� � N.4m S� � Ne arn s� se� 3 � m Ne 3rd PI ,o� � Greenwood � P Ne�d si < Memorial a � m`� � � Park Heather ; � �,� � Downs � � �6 � Park � � n Ne Ind St � Ne 2nd St ,`. �n� � '�(.� N�Ist Ct ► �,� r��,, Ne 1 st� t s > Ne lst St �ltt SI � Mt Olivet � � Se tse n Cemetery x � � 3�� Se 2nd St , �lnd G � � Se Ird St � � S°I"d� St � � �3 'y ��Sr ���St � A ��� q a� x ��4�t`�' SITE p i '�,i9�o \�-�` — ' M+Pi Se StA SI < �� ta. ��av�.fi�h x��ts�st �' %, �,� � s� Maplewood 5e te�se � ` Park � � � _ � tM, , .. . 'f�'/Mth St � h PI - .._.<�� �/ p����'Y� Maplewood Golf Course � '� I i ` Ce�� $1 '� x �`y � ��nr ,� v� ` a"•� � � f •��` da�p y Ron Re� �4� ��� , � a�i�rqd Park �„f �#�w� �` raan w�r s� ,w �'� � �. . ' � ,� u��►'Ss a '�=m.��� �iy �'� un w � � "�'d�. � '� �.,+. � �� � � �'�r x � � �'�.�'• �'.� �,, �pk � � � � � � � ��s� r �" Tiffany ,9� ,� Se tSTthl' Park i� �'/�th5� 4 s Se 21 st St y ``��� � Se I�h S� r' S�156th S� Se 22nd% � S�1601h St � Se t60th St k/59�� S�159th% Se 1601h St v x � � Se I6tst St S h��YS� se���d s� � � � r '� �Park e ,3�t. X' s ,� �roa � �` �6j r � S�16Ad 51 � � N g ^`�r � Se J6,� J 9 Se t62nd M St ^ : Se 16kh k St Sa 16�th St �F c_,._ _ �A�.� REFERENCE: Rand McNally(2014) Scale: FOr: Job Number Horizontal: N.T.S. VeRical: WA PLAT OF COPPERWOOD 16834 GHAV 1821572NDAVENUESOUTH RENTON, WASHINGTON � n► s� KENT,WA 98032 m y Z (425)251-6222 Tit/e: � S � (425)251-8782 VICINITY MAP 1 = �� �'U, �' CIVIL ENGINEERING,LAND PLANNING, <T f,P �NC eNG�H� SURVEYING,ENVIRONMENTAL SERVICES DATE:04/16l14 P:116000s1168341exhibitlgraphics116834 vmap.cdr I „ �3 - IS ''"_ . � i_� . � � . a.i. . � -.. ....� . .e.. ... ,� � � �i-M ..+ , �' � . tAlpt UNO W IDt D��NO S�� .. � _ 13 � 11 `'-.. . - � 6 61 6� !0 ��5� ..S� � ST )�] �lnl• .••ldA ' F .• ��� • -�• ..:.. u eei�oz - . � ! - R : .. .��• _ � ��:: [„ h . . _,c ���:�� n:,y ' L.. � � x_. ^ •m .: � ' " ». .�.. . ,; c;?C . . �c �e n 10 .. r�a}j'�`-_-�^ -. � r. '.. . - a. . iwj � f`' - ��� r „ . 6 E 17QTH S � �� e - ' - u..s� . . ..sP`:�']oCfiaYUW� _:�.. . ��'� ... iis.LTI �� r „ .Y5 4 �'"p 's - �`�.`fG• � LOit - ' �... 3 - � _�. . 7�U " "' '' x'. 1 - � _,.:._ ' . ��' �..V� e , � ^��. , 4 _ �. _ .. :� �� - ;o' a ` a ME . 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SRI30 r � _ r - : n mq ' , .. - . �:� B� +� E �r ' = 91GJ 1 l aN�i � .. : . "�. �,:. '. . ,,. .::; ' . E� _�,:_ ;:�" - c:30 � �.N i.>{ y t . .._... -w.�w+n H».n , ;,.. ,^� r ' . y � , , , st2ao`.�� a '' ' : ��,_ , {' _.. `Y � _- .. „ REFERENCE: King County Department of Assessments(Dec. 2011) S�,e: For: Job Number Horizontal: N.T.S. Verticaf: N/A PLAT OF COPPERWOOD 16834 �Ha� 1g21572NDAVENUESOUTH RENTON, WASHINGTON � ��► s� KENT,WA 98032 m 'y Z (425)251-6222 Tit/e: o � i. (425)251-8782 ASSESSOR MAP Z�� •` CIVIL ENGINEERING,IAND PLANNING, �r� ��� SURVEYING,ENVIRONMENTAL SERVICES DATE:04/16/14 ^'a�na�N P:V6000s1168341exhibitlgraphics116834 amap.cdr ■ �i Figure 3 Drainage Basins, Subbasins, and Site Characteristics � � �� � , . __.—__��_�,:,�_ �_ . � � ' Northern r` . : �y r �i✓ / _ � i:�: ; - Tributaries ' ' Subarea . � --� . _ � � 1 1'.'ac'e..3t! - r .. z� .�,�� ��_o�:r� ��, : �, ,_ __ � ,4 .�'j . � ;--- Figure 3-t � -ti,- - , ..� .. �.� f. - -- Mainstem :�• •`^ ' • . . ___ Suborea : � , �� cn��9 r+a� ; :� ` `�` � --� '--�' � `� �''°'" � ���`�'Y' � Subarea Boundaries - RENTON ...:• - ' ��,o , , • � � ���`�� , � �` `., , ; . j }` I ����r� \. �����• ��, l.. J � � .. ;a1 �'� � �• `• • ; j� , � 1 � \ . • �, i ♦ — — ;'� ' �. 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Vertical: N/A PLAT OF COPPERWOOD �GHA vs 16834 1821572NDAVENUESOUTH RENTON, WASHINGTON � n► � KENT,WA 98032 47 y Z (425)251-6222 Tlfl@: ° ° " �425�25� 8�82 SOIL SURVEY MAP ' °y r �����,, dp�' CIVIL ENGINEERING,LAND PLANNING, NQ eNG�p6 SURVEYING,ENVIRONMENTAL SERVICES DATE:04/16114 P:116000s1168341exhibitlgraphics116834 soil.cdr � � � � � Q � � .� W � � � _ _ _ `� ! , � � SG,�TycaS� �3?!yD STREET Q h SOUTHEAST 136TH STREET oz, � W ZONE X I— z � w w O E � � 15 = � 9 � � � z �i N � Y <^ U ,� 0 � � � SITE . f � � SOU?HEAST � CCRPORATE LIMIl'S `�� ;? _ ; / c � ` CITY OF RENTON � sF �aorH g < 530088 S` "` _ �-- � W STREFT a - < _ _ z - ,4',,S? j' S 7 v r� �� • � SE 140TH � � _.� � a "' P�_ACE � aJ ` _ � .rL c � � ? `�; ',c2`.D ry O � � � �-� ^O� (p / � ��P�� a �p '�� ..1 S� 142'`� w pJ � �- .'�� ' �n `' � Q Z PLACF u' w , SO ; a � Q x � J �Th��� � � �9is Q g d ST � a LEGEND � � c�rfiER ��F.�t �c �, � KING COUNTY F a zoNe x ,. , ,.� , �, .�_.., .�,-.,., ...�.. , �---�-— � 144TH STREET ' i' � CITY OF RENTON REFERENCE: Federal Emergency Management Agency(Portion of Map 53033C0982 F, May 1995) Sca/e: FO/': Job Number Horrzontal: N.T.S. Vertical: N/A PLAT OF COPPERWOOD �GHAV� 16834 1821572NDAVENUESOUTH RENTON, WASHINGTON � t►►� � KENT,WA 98032 m � Z (425)251-6222 Tif/e: 0 3 i (425)251-8782 FEMA MAP y�� �' CIVIL ENGINEERING,LAND PLANNING, �r�NQ tN6�N��p SURVEYING,ENVIRONMENTAL SERVICES DATE:04/16/14 P:I160GOs1168341exhibitlgraphicsll6834 fema.cdr Figure 6 Sensitive Areas Map ,� � '�"' �� ��l�f`,�i���°'s.. g. ��_.� � .� �'�, ' � � a � � '�'`�B�`� �--� �- , �. .�:� � ���y ' s°� • r" ,� .� �i Ea��� ,� ���� ' , �r�� " � '�---�--�-L ►� � � � ,� .+►�� �� -: .�� � �� .„", ' •�.'!E"/ � � � ' .+� r �� ;�� � � �� �� .�� �E' � � � �e � � ( �� Y�� �i � _ ��»} Y �� ! r,_,.! �' �� ' � � a� r� �+� . ����..�° � r _._.:�� � �*� � _ _ � ��.� .----� �����,� � � �, - �- m��o ���� -- -— - . . �,. . • �-�---, �s,�,aitil, _ • �� ���.= � - , Y,� � ��� _�,: 1 �� �� � ; � ��� �_ � �,-,�— � �, , �� �T � ��` , � �..� � �� � _ �� -- � � �''�'� - *;� ' �� �� �.�� �y. � � , �. �� !� . � '` � '�+a � � � �. � -s ,� _�.� `� -.�.�' � � �� � .� � � , �va�, . �. � r .�. � - � �,-'"� .� � �� , � a . - : ';� 5� � � ' � E �? � � � � ��J �� •� � �': I+ j ' � - ! � r�� �. I �! - ' x� �' Mt ��— '� � � � . ,t=-. — ° F- -�-�--�- .$ ' •-° i►` '�` � �"� =� �c.�` `�f < ,..— ,�, . � .. - _ . , _ : � �j - � : K� � ������ ������ ��� - . � � �� A � �� �'; 3 �� ��� t � � ..;�� -�. ► � � . � r�� �� _: _. , : � . r�. :� �� � ; .��� �._� � '�����k' �,{€ Y -- �� , Lege��d City and County Boundary � Shoreline Residential Other � urban Conservancy �:� CtydReMon � Jurisdictions Parcels Slope City of Renton >>s+c a<-zsx >zsx a�ox��� ■ >40%3 a90%(Proteded) � '°0'� �'°'°� REFERENCE:www.rentonweb.org(2014) Scale: FO/': Job Number Honzontal: N.T.S. Verfical: N/A PLAT OF COPPERWOOD 16834 GHAV 1821572NDAVENUESOUTH RENTON, WASHINGTON � n► S� KENT,WA 98032 m , Z (425)251-6222 Tifle: � 3 � (425)251-8782 SENSITIVE AREAS :.` �II U� ,_ �r �p CIVIL ENGINEERING,LAND PLANNING, MAP �N�eNc�N� SURVEYING,ENVIRONMENTALSERVICES DATE:04/16/14 P:I16000sI168341exhibitlgraphics116834 amap.cdr 2.0 CONDITIONS AND REQUIREMENTS SUMMARY 2.1 Analysis of the Core Requirements Core Requirement No. 1: Discharge at fhe Natural Location. Response: The runoff from the existing site leaves near the southeast corner via an on-site creek (Maplewood Creek Tributary 0303). The proposed detention pond will discharge into the creek, maintaining the natural discharge location for the site. Core Requirement No. 2: Off-Site Analysis. Response: An Off-Site Analysis has been performed pursuant to the 2009 KCSWDM and 2010 City of Renton Amendments to the KCSWDM. Please refer to Section 3.0 for further detail. Core Requiremenf No. 3: Flow Control. Response: Flow Control Duration Standard Matching Forested Site Conditions is required. Flow control requirements will be met by a detention pond, designed pursuant to the 2009 KCSWDM and the 2010 City of Renton Amendments to the KCSWDM. See Section 4.0 for more information. Core Requirement No. 4: Conveyance System. Response: The conveyance system has been designed pursuant to the 2009 KCSWDM and the 2010 City of Renton Amendments to the KCSWDM. Conveyance and backwater calculations are provided in Section 5 of this report. Core Requirement No. 5: Erosion and Sediment Control. Response: Temporary erosion control measures are provided in the final engineering plans. Core Requirement No. 6: Maintenance and Operations. Response: Please refer to Section 10.0 for the Maintenance and Operations guidelines associated with the proposed storm improvements. Core Requirement No. 7: Financial Guarantees and Liability. Response: The project will provide a Site Improvement Bond Quantity Worksheet to establish a bond amount for drainage facility restoration and site stabilization financial guarantee prior to construction. Core Requirement No. 8: Water Quality. Response: Enhanced Basic water quality is required for this project. This requirement is satisfied by utilizing a two facility treatment train consisting of a wetpond followed by a StormFilter vault. Please refer to the calculations within Section 4.0 of this report. 2.2 Analysis of the Special Requirements Special Requirement No. 1: Other Adopted Area-Specific Requirements. 16834.015.doc Response: The proposed project is located in the Lower Cedar River Basin Area. A report was prepared by King County (See portions in Appendix A)which requires Level 2 Flow Control (Flow Control Duration Standard Matching Forested Site Conditions per the 2010 City of Renton Amendments to the KCSWDM) and Basic Water Quality for the project. Special Requirement No. 2: Flood Hazard Area Delineation. Response: As indicated by the FEMA Map included in this report, the proposed site does not lie within a floodplain or floodway of a stream, so this special requirement does not apply. Special Requirement No. 3: Flood Protection Facilifres. Response: This project does not rely on an existing flood protection facility or propose to modify or construct a new flood protection facility, so this special requirement does not apply. Special Requirement No. 4: Source Control. Response: The project does not require a commercial building or commercial site development permit, so this special requirement does not apply. Special Requiremenf No. 5: Oil Confrol. I Response: This site is not classified as a High Use Site given the criteria in the 2009 KCSWDM, so this special requirement does not apply and no special control treatment is necessary. Special Requirement No. 6: Aquifer Protection Area Response: The project site is not located within an Aquifer Protection Area and, therefore, this special requirement does not apply. 2.3 Hearing Examiner Conditions The proposed preliminary plat, street improvement modifications and critical areas exemption are approved, subject to the following conditions: 1. The applicant shall comply with mitigation measures issued as part of the Mitigafed Determination of Non-Significance for the proposal. Response: The condition will be satisfied by the approval of the construction drawings. 2. All proposed street names shall be approved by fhe City. Response: Street names will be designated and approved by the City. 3. Al!!ot comers at intersections of dedicated public rights-of-way, except a!leys, shal/ have minimum radius of�fteen feet(15). Response: The condition will be satisfied by the approval of the construction drawings. I 16834.015.doc 4. Side sewer lines sha!!be installed eight feet (8) into each lot if sanitary sewer mains are available, or provided with the subdivision development. Response: The condition will be satisfied by the approval of the construction drawings. 5. A!! utilities designed to serve the subdivision shall be placed underground. Any utilities installed in the parking strip sha!! be placed in such a manner and depth to permit fhe planting of trees. Those utilities to be located beneath paved surfaces shal! be insfalled, including all service connections, as approved by the Department of Public Works. Such installation shall be completed and approved prior to the application of any surface material. Easements may be requrred for the maintenance and operation of utilities as specified by the Department of Public Works. Response: The condition will be satisfied by the approval of the construction drawings. 6. Any cable TV conduifs shal! be undergrounded at the same time as other basic utilities are installed to serve each lot. Conduit for service connections shall be laid to each lot line by Applicant as to obviate the necessity for disturbing the streef area, including sidewalks, or alley improvements when such service connections are extended to serve any building. The cost of trenching, conduit, pedestals and/or vaults and laterals as wel! as easemenfs therefore required to bring service to the development shall be borne by the developer and/or land owner. The applicant shall be responsible only for conduit to serve his development. Conduit ends shall be elbowed fo final ground elevation and capped. The cable N company shal!provide maps and specifications to the applicant and shall inspect the conduit and certify to the Crfy that rt is properly installed. Response: The condition is noted and will be applied. 7. The applicant shall be required to record the Copperwood lot line adjustment (LUA14-000730)prior to Fina!Plat Recording. Response: The Copperwood Lot Line Adjustment will be recorded prior to Final Plat Recording. 8. Additional trees shaU be planted within the provided 25-foot open space tract along the western border of the site, specifically the planting of additional trees to replace removed trees within the tract that have been considered dead, diseased or dangerous (Exhibit 13J. Additionally, the applicant sha!! be required to plant fwo evergreen frees, per lot, along the southem perimeter of the site. These shal! be placed into an easement identifying the requirement for retention of the trees in perpetuity, if removed such trees shall be replaced at a 1:9 ratio. Such landscaping or landscape plus fencing shall be, at a minimum, 6-feet high at maturity and at least 50 percent sight-obscuring. Existing healthy mature trees whrch are located within the 25-foot wide open space tract shall 6e maintained and protected during ; construction unless determined by an Arborist that such tree is dead, diseased, or dangerous. A revised landscape plan shall be submitted to, and approved by, the Current Planning Project Manager prior to construction permit approval. Response: The condition will be satisfied by the approval of the construction drawings. 16834.015.doc 9. Open space tracts shall be shown and recorded on the face of the plat to be preserved in perpetuity. Response: The condition will be satisfied by the approval of the Final Plat. 10. A!! structures proposed for remova! or relocation shall be demolished and/or relocated and all inspections complete prior to Final Plat approval. Response: The condition is noted and will be completed prior to Final Plat approval. 11. The applicant sha!! be required to submit a revised landscape plan, depicting a 10- foot wide on-sife landscape strip for a!!lots. The fina! detailed landscape plan shal! I, be submitted to and approved by the Current Planning Project Manager prior to ', construction permit approval. Such landscaping shall include a mixture of trees, , shrubs, and groundcover as approved by the Department of Community and Economic Development. ' Response: A revised landscape plan depicting the require 10-foot-wide buffer will be submitted and approved before prior to construction permit approval. 12. The applicant sha!! eliminate access directly from S.E. 2nd Place for proposed Lot 46. As an alterrtatrve the applicant may provide shared access to tot 46 via the internal looped road. The revised plat plan sha!!be submitted to, and approved by, the Current Planning Project Manager prior to construction permit approval. Should the revised plat plan result in an additional access easement/righf-of-way dedication the applicant shall be required to submit a revised density worksheet wifh the revised plat plan demonstrating compliance with the density requirements of the R-4 zone. Response: Lot 46 will be provided access to proposed Road C via a 16-foot-wide shared driveway easement on Lot 47. All appropriate changes will be reflected on the revised plat plan. 13. The applicanf shal! submit a Fina! Stream Mrtigation Plan for impacts (tight-lining of drainage system, trail, and buffer averaging) to the critica! area buffer. The Final Mitigation Plan shall be submitted to, and approved by, the Current Plannrng Project Manager prior to utility construction permit approval. The applicant shall a/so establish a IVative Growth Protection Easement over that part of the site encompassing the stream and buffer area and place fencing and signage along the outer buffer edge which would include the buffer edge along the wesf side of 143rd Ave S.E. Response: This condition will be satisfied by the approval of the Final report and plan prepared by Soundview Consultants. 14. The applicant shalJ revise the S.E. 2nd Place cross section to transition to the code required street standard (landscaping in befween the sidewalk and the curb) at the eastern boundary of the Maplewood Creek buffer. The revised street cross secfion shall be submitted to, and approved by, the Current Planning Project Manager prior to construction permit approval. Response: The condition will be satisfied by the approval of the construction drawings. 15. The applicant shall be required to place a split rail fence along the eastern boundary of the critical area/open space tract adjacent to the modified 143rd Avenue S.E. 16834.015.doc Response: This condition will be satisfied by the appro�al of the Final report and plan prepared by Soundview Consultants. 16. The applicant shal! be required to submit a Final Mifigation Plan demonstrating compliance with the drscharge meefs the requirements of the Storm and Surface Water Drainage Regulafions (RMC 4-6-030); wil! not result in significant adverse changes in the water temperature or chemica! characteristics of the stream; and there is no increase in the existing rate of flow (RMC 4-3-050C.5.d.i). The Fina! I Mitigation Plan shall be submitted to, and approved by, the Current Planning Project ', Manager prior fo construction permit approval. Response: This condition will be satisfied by the approval of the Construction Plans and this Technical Information Report. 17. The applicant shal!submit a revised plat plan depicting fhe eliminafion of the lof (Lot 47) within the subdivision. The applicant may submit an alternative plan which provides access to Lot 47 according fo RMC 4-6-060, Street Sfandards. Should the revised plat p/an result in an additional access easemenf/right-of-way dedication fhe applicant shal! be required to submit a revised density worksheet demonstrating compliance wifh fhe density requirements of the R-4 zone. The revised plat plan, and density worksheet if needed, shal! be submitted to and approved by the Current Planning Project Manager prior to construction permit approval. Response: The condition will be satisfied by the approval of the construction drawings. 18. The applicant shall provide a designated crosswalk, across S.E. 2nd Place, to connect to the exisfing sidewalk on the north side of street. Alternatively the applicant may designated walking path, on fhe south side of S.E. 2nd Place, east of the subject property to an existing S.E. 2nd place crosswalk, in order to provide a safe route to school/designated school bus stops. A safe route to school/designated schoo! bus stops plan shall submitted to, and approved by the Current Planning Project Manager, prror to construction permit approval. Response: The condition will be satisfied by the approval of the construction drawings. 19. The applicant shal! be required to create a homeowners' association and maintenance agreement(s) for the shared utilities, stormwater facilifies, and maintenance and responsibilities for all shared improvements of this development. A draft of the document(s) shall be submitted to Current Planning Project Manager for review and approva!by the City Attorney and Property Services secfion prior to the recording of the fina!plat. Response: Acknowledged as a final plat item. 20. The signage required for the split rail fence along 143rd Ave S. sha!! provide that dumping into the ravine is prohibfted. Response: This condition will be satisfied by the approval of the Final report and plan prepared by Soundview Consultants. 21. The proposal shal! be subject fo the mrtigation measures recommended in the 1 D/13/14 memo to the Examiner, Ex. 27. The staff recommends the following conditions of approval. , 16834.015.doc �I 21.1 Hand remove grass and other debris dumped on the bank fhat continues to saturate the hillside that prevents natura! vegetated to grow on the bank (immediately adjacent to 13652 and 13660 143rd Avenue S.E.) and plant nafive vegetation along fhe bank. The proposed planting plan shall be included in the Fina! Mitigation to be submitted to, and approved by, the Current Planning Project Manager prior to construction permit approval. Response: This condition will be satisfied by the approval of the Final report and plan prepared by Soundview Consultants. 21.2 The applicant shall grind and overlay from the centerline of the existing asphalt to the edge of road that fronts the project on 143rd Avenue S.E. Response: The condition will be satisfied by the approval of the construction drawings. 2.4 SEPA Conditions 1. A!!earthwork performed, implemented by the applicanf, shal! be consistent with the recommendations of the geotechnica! report, prepared by Terra Associates, lnc., dated February 10, 2015 Response: The condition will be satisfied by the approval of the construction drawings. 2. The applicant shall provide a 50-foot horizonta!setback distance from the maximum stored water elevation in the pond to the crest of the ravine slope. As an alternative fo a setback the applicant may choose to line the pond with a flexible membrane liner to prevent seepage losses. The final drainage plan shall be submitted to, and approved by, the Plan Revrewer prior to construction permit approval. Response: The condition will be satisfied by the approval of the construction drawings. 3. Site construction shall be restricted to the dry weather months (Apri! 1sf through September 30th). Response: The condition will be satisfied by the approval of the construction drawings. 4. The �na! drainage report shal! include a more detailed upstream, downstream, and potential erosion analysrs. Per CORE requirement #2, a Leve! 2 downstream analysis is required to better understand erosion and possible concentration of runoff in erosion sensifive downstream bodies. The applicant should note that a Leve! 3 flow control could be required as part of the Level 2 downstream analysis. A revised fina! drainage report and associated plans, based on the 2009 King County Surface Water Design Manual as amended by the City of Renton, is required to be submitted to the satisfaction of the Plan Reviewer prior to construction permit approval. Response: This condition will be satisfied by the approval of this Technical Information Report. 5. The applicant shal!design the proposed drainage facility utilizing the Enhanced Basic water quality menu. A revised final drainage report and associated plans utilizing fhe Enhanced Basic water quality menu, based on the 2009 King County Surface Water 16834.015.doc Design Manual as amended by the City of Renton, is required to be submitted to fhe satisfaction of fhe Plan Reviewer prior to the construcfion permit approval. Response: This condition will be satisfied by the approval of the Construction Plans and this Technical Information Report. 6. The applicant shall be required to provide, to the Current Planning Project Manager, tree retention inspection/monitoring reports after initial clearing, �nal grading, and annually for two years by a quali�ed professiona!forester. The inspection/monitoring reports shal! identify any retained trees that develop problems due to changing site conditions and prescribe mitigation. Response: This condition will be satisfied by the approval of the Final Tree Protection Plan prepared by Washington Forestry Consultants, Inc. 16834.015.doc 3.0 OFF-SITE ANALYSIS TASK 1 STUDY AREA DEFINITION AND MAPS The proposed Plat of Copperwood is a single-family residential project consisting of 47 lots zoned R4, and will be utilizing the small lot clustering provisions. The project is 12.68 acres in size containing 8 tax parcels (152305-9066, 152305-9067, 152305-9201, 152305-9100, 152305-9093, 152305-9170, 152305- 9043, and 152305-9221). The site is located at the intersection of 143rd Avenue S.E. and S.E. 2nd Place, in a portion of Section 15, Township 23 North, Range 5 East, W.M., in the City of Renton. , The site is rectangular in shape, and fronts S.E. 2nd Place. The proposed on-site roads are to be tied into S.E. 2nd Place, and will be extended into the site to provide public access and circulation. This site is currently developed, with 7 single-family residences, and is currently zoned R4. The existing on-site improvements consist of storm and water utilities, and gravel driveways that access S.E. 2nd Place. There is an on-site creek (Maplewood Creek Tributary 0303), on the eastem quarter of the project site. The creek enters onto the north side of the property via an existing 48-inch culvert that crosses underneath S.E. 2nd Place. The creek flows in a south easterly direction into the existing Right of Way of 143rd Avenue S.E. before meandering back into the subject property; the creak ultimately leaves the property at the south side of the project. In the existing condition, runoff generated onsite flows in an _ easterly fashion towards Maplewood Creek Tributary 0303. In the developed condition generated runoff will be collected by a system of storm drain pipes and routed to a detention wet pond for flow and water quality control, and will ultimately be discharged directly to the creek from the proposed drainage facility. The site is bound along the east property line by 143rd Avenue S.E. and Maplewood Creek Tributary 0303. Along both the south and west boundaries the site is bound by single-family residences. It should be noted that the southeast corner of the site contains steep slopes, ranging from 15 percent to 70 , percent. These steep slopes are to be contained within a Natural Growth Protection Area (NGPA) Tract. S.E. 2nd Place bounds the site along the north. Access to the site from S.E. 2nd Place will require frontage improvements, including new asphalt, new curb and gutter, sidewalk, and planter strip. On-site soils are mapped as Alderwood. Please refer to the Soils Map within Section 1.0 of this report. All drainage calculations were modeled as till soils. The project will be constructing roadways consisting of curb and gutter, sidewalk, and street trees. The site will tie into the existing road at S.E. 2nd Place. All roads for this project have been designed to be 26 feet wide, with an 8-foot planter strip at the back of curb and a 5-foot sidewalk (both sides). Overall, the proposed public right-of-way is to be 53 feet in width. The topography on-site is generally flat, with a slight rise in the westernmost portion of the site. The site generally slopes from west to east, toward Maplewood Creek Tributary 0303, from elevation 398 to 386. The project will be mass graded with cuts and fills balanced on site. The proposed development also includes further restoration of the Maplewood Creek Tributary 0303 buffer area. The drainage facilities are required to meet the requirements of the 2009 King County Surface Water �� Design Manual (KCSWDM), and the 2010 City of Renton Amendments to the KCSWDM. The drainage ' design shall meet, at a minimum, the Flow Control Duration Standard Matching Forested Site Conditions. I The project has been conditioned to provide Enhanced Basic Water Quality Treatment. The drainage facility located in Tract B is a combination detention/wet pond, sized for Flow Control Duration Standard I Matching Forested Site Conditions. The basic wet pond will be sized pursuant to the 2009 KCSWDM and I the City's amendments. In addition to the basic wet pond a StormFilter with CSF (leaf compost) media will be used to satisfy the Enhanced Basic Water Quality Treatment requirement. Upon treatment, stormwater will be discharged to Maplewood Creek Tributary 0303, via a riprap pad at the edge of the ordinary high water mark of the creek channel. Please refer to Section 4.0 for detailed drainage calculations. 16834.015.doc UPSTREAM DRAINAGE ANALYSIS: The subject property is bound by S.E. 2nd Place to the north, a ridgeline along the western property line, and Maplewood Creek Tributary 0303 to the east. The onsite topography slopes in a southerly direction, which means that there is no upstream basin tributary to the project site. However, as mentioned above, Maplewood Creek Tributary 0303 enters the north side of the project via a 48-inch culvert that crosses undemeath S.E. 2nd Place. The basin tributary to this creek is very large with respect to the overall project site. Utilizing the City of Renton's Surface Water Network map, available on the City's website, and LIDAR topographic maps we were able to estimate the size of the contributing basin to the creek at the culvert crossing to be approximately 535 acres. This basin is a mixture of residential neighborhoods of various zoning, commercial properties, sensitive areas, drainage facilities, city streets, parks, and other various uses. Per the 2009 KCSWDM and the 2010 City of Renton Amendments the upstream analysis shall include an evaluation of the upstream drainage system to verify and document that significant flooding and erosion impacts will not occur as a result of the proposed project. Based on our review of all of the known available data, which includes requests from the City and King County for drainage complaints, and the adopted Lower Cedar River Basin and Nonpoint Pollution Action Plan, there are no known flooding problems associated with the 48-inch culvert that crosses underneath S.E. 2nd Place into the property. Additionally there is no evidence that suggests that the existing culvert is not operating correctly. There are no impacts to the existing culvert as a result of the proposed development. No additional flows are being added and the culvert is not being modified as a result of construction. Since ' there are no known flooding/conveyance issues associated with the existing culvert and no impacts to the existing culvert as a result of the proposed development, no further analysis is required. For further detail please refer to the Upstream Basin Area Map located within this section. 16834.015.doc TASK 2 RESOURCE REVIEW I . Adopted Basin Plans: The site is located within the Lower Cedar River Basin. Refer to Appendix A for the portions of the basin that applies to this project. � • Finalized Drainage Studies: This is not applicable. • Basin Reconnaissance Summary Report: This site is located in the Lower Cedar River Basin, which is covered by the Lower Cedar River Basin and Nonpoint Pollution Action Plan dated July 1997 (included in Appendix A). • Critical Drainage Area Maps: This project will not discharge to any critical areas or wetlands as it will be discharging runoff from the detention pond to Maplewood Creek Tributary 0303, matching pre-developed flows. Therefore, no critical areas are to be affected. ' • Floodplain and Floodway FEMA Maps: Please see the attached FEMA Map (Section 1.0) utilized for this analysis. As indicated on the map, the site is located in Zone X and is outside of the 500-year floodplain. � • Other Off-Site Analysis Reports: A site investigation was conducted in preparation of the Level2 Off-Site Drainage Analysis. The United States Department of Agriculture Soils Conservation Service Map is also provided. See Figure 4—Soils Map in Section 1.0. 'I • Sensitive Areas Folios: Based on review of the King County Sensitive Areas Map Folios, the 'I site does not contain any On-Site Wetlands, Erosion Areas, Sensitive Areas, or Land Slide Areas. I • Road Drainage Problems: This is not applicable. • United States Department of Agriculture King County Soi/s Survey: Based on the Soils Map (Figure 4 — Soils Map, Section 1.0) for this area, the site is underlain with Alderwood gravelly sandy loam. The soils were modeled as till soils. • Wetland lnventory Map: From the Wetland and Fish and Wildlife Habitat Assessment Report by Soundview Consultants, there is no known documentation or inventory of wetlands for the project site. . Migrating River Studies: This is not applicable. • City of Renton Aquifer Protection Zones: Per the City of Renton's GIS Map, the project site is not located within an Aquifer Recharge Area. • King County Drainage Complaints: We received two drainage complaints from King County within the downstream corridor of Maplewood Creek. Per discussions with King County representatives, complaints within areas annexed by the Ciry of Renton have been forwarded to the City for filing. Per the 2009 KCSWDM we are only required to review complaints within the past 10 years. For further detail of these complaints, please refer to Appendix B. 16834.015.doc TASK 3 FIELD INSPECTION 3.1 Conveyance System Nuisance Problems (Type 1) - Conveyance system nuisance problems are minor but not chronic flooding or erosion problems that result from the overflow of a constructed conveyance system that is substandard or has become too small as a result of upstream development. Such problems warrant additional attention because of their chronic nature and because they result from the failure of a conveyance system to provide a minimum acceptable level of protection. There were no conveyance system nuisance problems observed during the site visit. Furthermore, based on a review of the drainage complaints received from the City of Renton, ' there is no evidence of past conveyance system nuisance problems occurring in the direct I downstream drainage course, as there is a record of none having been submitted. This site will have a flow control facility, which will restrict the flow to match developed discharge durations to pre-developed durations for the range of pre-developed discharge rates from 50 I percent of the 2-year peak flow up through the full 50-year peak flow and match developed peak '' discharge rates to pre-developed peak discharge rates for the 2- and 10-year return periods, all while assuming forested site conditions. This level of flow control will provide adequate mitigation to prevent any future drainage complaints as a result of this proposed site development. 3.2 Severe Erosion Problems(Type 2j Severe erosion problems can be caused by conveyance system overflows or the concentration of runoff into erosion-sensitive open drainage features. Severe erosion problems warrant additional attention because they pose a significant threat either to health and safety or to public or private property. Erosion is a natural occurrence, especially in drainage courses within ravines. Erosion is the natural creation process of ravines. In the instance where there are Severe Erosion Problems within the downstream drainage course as there is within Maplewood Creek Tributary 0303 and 0302, the King County Drainage Manual and City of Renton Amendments requires that a project provides the Flow Control Duration Standard Matching Forested Conditions within its detention facility. This flow control standard is designed to prevent the initiation or aggravation of existing channel erosion and instability. It is a durational standard that limits the time span during which post-developed flows exceed an erosion-causing threshold to its pre-developed level. Per Table 1.2.3.A of the 2009 King County Surface Water Design Manual and 2010 City of Renton Amendment if Severe Erosion Problems are identified downstream and the project provides this level of flow control,then no further flow control is required. 3.3 Severe Flooding Problems (Type 3) Severe flooding problems can be caused by conveyance system overFlows or the elevated water surfaces of ponds, lakes, wetlands, or closed depressions. Severe flooding problems are defined as follows: • Flooding of the finished area of a habitable building for runoff events less than or equal to the 100-year event. Examples include flooding of finished floors of homes and ' commercial or industrial buildings. Flooding in electrical/heating systems and components in the crawlspace or garage of a home. Such problems are referred to as "severe building flooding problems." 16834.015.do� • Flooding over all lanes of a roadway or severely impacting a sole access driveway for runoff events less than or equal to the 100-year event. Such problems are referred to as "severe roadway flooding problems." Based on our site visit and a review of the available Drainage Complaints in conjunction with the Lower Cedar River Basin and Nonpoint Pollution Action Plan there is no evidence of severe flooding problems downstream of our site. 16834.015.doc �'� � TA K 4 DRAINAGE YSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS S S �', LEVEL 2 DOWNSTREAM DRAINAGE ANALYSIS: In the pre-developed condition, all runoff drains to the Maplewood Creek Tributary 0303. Once it is collected by the creek tributary, it leaves the site at the southeast corner. In the developed condition, stormwater that is discharged from the site will be conveyed from the detention pond to Maplewood Creek Tributary 0303. Steep slopes exist near the southeast corner of#he NGPA, ranging from 15 percent to 70 percent. Stormwater from the detention pond will be discharged via a bubble-up manhole that is armored with riprap. The riprap will help dissipate the outflows of the pond. In addition to the bubble-up manhole and riprap armoring, the outlet will be placed at the edge of the stream channel, just above the ordinary high water mark to ensure no runoff is being introduced over the slopes of the channel. The proposed detention pond was designed to provide the Flow Control Duration Standard Matching Forested Condition Areas. Based on our site visit and a review of the available drainage complaints in conjunction with the Lower Cedar River Basin and Nonpoint Pollution Action Plan it is clear that there are Severe Erosion Problems along the downstream corridor. This includes portions of Maplewood Creek Tributary 0303 and Maplewood Creek Tributary 0302. Based on the testimony provided by the public during the hearing process and a review of the drainage complaints it appears that a majority of the erosion concerns can be attributed to landslides on the banks of the ravines. Of the drainage complaints we obtained one is on a portion of Tributary 0302 that is upstream of our drainage course. The other is within the '/< mile downstream corridor of the project. We have included the complaint on Tributary 0302 for reference as it shows that much of the erosion within this corridor is attributed to runoff that is directed onto the existing slopes, which are highly erodible. The drainage complaint within '/4 mile of the project site is not really a complaint as it doesn't point out a specific drainage issue. It is our understanding that the property owner associated with this drainage complaint submitted a letter to the City of Renton as part of this projecYs hearing process. We have included a copy of this letter (Exhibit 11 from the Staff Report to the Hearing Examiner) along with the drainage complaints in Appendix B. The claim by the property owner is that trees are falling within the ravine due to the creek bed being washed out. If the existing trees are within the creek bed it is highly likely that they will eventually fall due to the streams natural erosion process. It is inevitable for a stream bed to erode over time and any tree roots within the stream bed will be exposed. It is important to note that as slides happen and other various blockages of the stream occur from fallen vegetation or other foreign objects, the stream will continue to correct itself over time. This may lead to additional slides within the ravine, but as stated above, this is the natural process of the stream itself. For further detail please refer to the drainage complaints within Appendix B. As part of this Level 2 downstream analysis we mapped the contributing basin areas to Maplewood Creek Tributary 0303 and Maplewood Creek Tributary 0302. We found that these basins are made up of a mixture of residential neighborhoods of various zoning, commercial properties, sensitive areas, drainage facilities, city streets, parks, and other various uses. The basins were mapped using a combination of LIDAR topography, King County Assessor Data, and the City of Renton's Surface Water Network map located on the City's website. The basin feeding Maplewood Creek Tributary 0303 is approximately 535 acres in size at the point where it enters the proposed project. The proposed project is slightly less than 13 acres in size or approximately 2 percent of the overall basin. At the point where Tributary 0303 joins Tributary 0302 an additional 297 acres of basin area is added, which means the project is approximately 1 percent of the total area tributary to both drainage courses combined. At this point the downstream corridor is beyond the '/4 mile downstream point from the project site. A Level 2 Downstream Analysis is a rough quantitative analysis of any downstream flooding, erosion or nuisance problems. It is evident from all of the public testimony and review of available data along with our site visit that issues surrounding the downstream drainage system are Severe Erosion Problems and not Severe Flooding Problems. Quantifying an exact erosion problem is not something that can be calculated because erosion is caused by continually high peak flows over a period of time. It is not possible to equate the peak flows from this project site to the peak flows of the overall basin and make a determination that the flows from this project will increase erosion, as we cannot determine what the naturally occurring erosion-causing threshold is. However, we can quantify what the overall basin area is and relate that to our proposed development. 16834.015.doc UPSTREAM DRAINAGE ANALYSIS: � The subject property is bound by S.E. 2nd Place to the north, a ridgeline along the western property line, and Maplewood Creek Tributary 0303 to the east. The onsite topography slopes in a southerly direction, which means that there is no upstream basin tributary to the project site. However, as mentioned above, Maplewood Creek Tributary 0303 enters the north side of the project via a 48-inch culvert that crosses I underneath S.E. 2nd Place. The basin tributary to this creek is very large with respect to the overall ' project site. Utilizing the City of Renton's Surface Water Network map, available on the City's website, and LIDAR topographic maps we were able to estimate the size of the contributing basin to the creek at the culvert crossing to be approximately 535 acres. This basin is a mixture of residential neighborhoods of various zoning, commercial properties, sensitive areas, drainage facilities, city streets, parks, and other various uses. Per the 2009 KCSWDM and the 2010 City of Renton Amendments the upstream analysis shall include an evaluation of the upstream drainage system to verify and document that significant flooding and erosion impacts will not occur as a result of the proposed project. Based on our review of all of the known available data, which includes requests from the City and King County for drainage complaints, and the adopted Lower Cedar River Basin and Nonpoint Pollution Action Plan, there are no known flooding problems associated with the 48-inch culvert that crosses underneath S.E. 2nd Place into the property. Additionally there is no evidence that suggests that the existing culvert is not operating correctly. There are no impacts to the existing culvert as a result of the proposed development. No additional flows are being added and the culvert is not being modified as a result of construction. Since there are no known floodinglconveyance issues associated with the existing culvert and no impacts to the existing culvert as a result of the proposed development, no further analysis is required. For further detail please refer to the Upstream Basin Area Map located within this section. 16834.015.doc I TASK 2 RESOURCE REVIEW � . Adopted Basin Plans: The site is located within the Lower Cedar River Basin. Refer to ' Appendix A for the portions of the basin that applies to this project. • Finalized Drainage Studies: This is not applicable. • Basin Reconnaissance Summary Report: This site is located in the Lower Cedar River Basin, which is covered by the Lower Cedar River Basin and Nonpoint Pollution Action Plan dated July 1997 (included in Appendix A). • Critical Drainage Area Maps: This project will not discharge to any critical areas or wetlands as it will be discharging runoff from the detention pond to Maplewood Creek Tributary 0303, matching pre-developed flows. Therefore, no critical areas are to be affected. • Floodplain and Floodway FEMA Maps: Please see the attached FEMA Map {Section 1.0) utilized for this analysis. As indicated on the map, the site is located in Zone X and is outside of the 500-year floodplain. • Other Off-Site Analysis Reports: A site investigation was conducted in preparation of the Level2 Off-Site Drainage Analysis. The United States Department of Agriculture Soils Conservation Service Map is also provided. See Figure 4—Soils Map in Section 1.0. • Sensitive Areas Folios: Based on review of the King County Sensitive Areas Map Folios, the site does not contain any On-Site Wetlands, Erosion Areas, Sensitive Areas, or Land Slide Areas. . Road Drainage Problems: This is not applicable. • United States Department of Agriculture King County Soi/s Survey: Based on the Soils Map (Figure 4 — Soils Map, Section 1.0) for this area, the site is underlain with Alderwood gravelly sandy loam. The soils were modeled as till soils. • Wetland lnventory Map: From the Wetland and Fish and Wildlife Habitat Assessment Report by Soundview Consultants, there is no known documentation or inventory of wetlands for the project site. . Migrating River Studies: This is not applicable. • City of Renton Aquifer Protection Zones: Per the City of Renton's GIS Map, the project site is not located within an Aquifer Recharge Area. • King County Drainage Complaints: We received two drainage complaints from King Counry within the downstream corridor of Maplewood Creek. Per discussions with King County representatives, complaints within areas annexed by the Ciry of Renton have been forwarded to the City for filing. Per the 2009 KCSWDM we are only required to review complaints within the past 10 years. For further detail of these complaints, please refer to Appendix B. � 16834.015.doc TASK 3 FIELD INSPECTION 3.1 Conveyance System Nuisance Problems (Type 1) Conveyance system nuisance problems are minor but not chronic flooding or erosion problems that result from the overflow of a constructed conveyance system that is substandard or has become too small as a result of upstream development. Such problems warrant additional attention because of their chronic nature and because they result from the failure of a conveyance system to provide a minimum acceptable level of protection. There were no conveyance system nuisance problems observed during the site visit. Furthermore, based on a review of the drainage complaints received from the City of Renton, there is no evidence of past conveyance system nuisance problems occurring in the direct downstream drainage course, as there is a record of none having been submitted. This site will have a flow control facility, which will restrict the flow to match developed discharge durations to pre-developed durations for the range of pre-developed discharge rates from 50 percent of the 2-year peak flow up through the full 50-year peak flow and match developed peak discharge rates to pre-developed peak discharge rates for the 2- and 10-year return periods, all while assuming forested site conditions. This level of flow control will provide adequate mitigation to prevent any future drainage complaints as a result of this proposed site development. 3.2 Severe Erosion Problems (Type 2) Severe erosion problems can be caused by conveyance system overflows or the concentration of runoff into erosion-sensitive open drainage features. Severe erosion problems warrant additional attention because they pose a significant threat either to health and safety or to public or private property. Erosion is a natural occurrence, especially in drainage courses within ravines. Erosion is the � natural creation process of ravines. In the instance where there are Severe Erosion Problems within the downstream drainage course as there is within Maplewood Creek Tributary 0303 and 0302, the King County Drainage Manual and City of Renton Amendments requires that a project provides the Flow Control Duration Standard Matching Forested Conditions within its detention facility. This flow control standard is designed to prevent the initiation or aggravation of existing channel erosion and instability. It is a durational standard that limits the time span during which post-developed flows exceed an erosion-causing threshold to its pre-developed level. Per Table 1.2.3.A of the 2009 King County Surface Water Design Manual and 2010 City of Renton Amendment if Severe Erosion Problems are identified downstream and the project provides this level of flow control, then no further flow control is required. 3.3 Severe Flooding Problems (Type 3) Severe flooding problems can be caused by conveyance system overflows or the elevated water surfaces of ponds, lakes, wetlands, or closed depressions. Severe flooding problems are defined as follows: • Flooding of the finished area of a habitable building for runoff events less than or equal to the 100-year event. Examples include flooding of finished floors of homes and commercial or industrial buildings. Flooding in electrical/heating systems and components in the crawlspace or garage of a home. Such problems are referred to as "severe building flooding problems." 16834.015.doc i � TASK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS LEVEL 2 DOWNSTREAM DRAINAGE ANALYSIS: In the pre-developed condition, all runoff drains to the Maplewood Creek Tributary 0303. Once it is collected by the creek tributary, it leaves the site at the southeast corner. In the developed condition, stormwater that is discharged from the site will be conveyed from the detention pond to Maptewood Creek Tributary 0303. Steep slopes exist near the southeast corner of the NGPA, ranging from 15 percent to 70 percent. Stormwater from the detention pond will be discharged via an 18-inch pipe onto a riprap pad. The riprap pad will help dissipate the outFlows of the pond, and will be placed at the edge of the stream channel, just above the ordinary high water mark to ensure no runoff is being introduced over the slopes of the channel. The proposed detention pond was designed to provide the Flow Control Duration Standard Matching Forested Condition Areas. Based on our site visit and a review of the available drainage complaints in conjunction with the Lower Cedar River Basin and Nonpoint Pollution Action Plan it is clear that there are Severe Erosion Problems along the downstream corridor. This includes portions of Maplewood Creek Tributary 0303 and Maplewood Creek Tributary 0302. Based on the testimony provided by the public during the hearing process and a review of the drainage complaints it appears that a majority of the erosion concerns can be attributed to landslides on the banks of the ravines. Of the drainage complaints we obtained one is on a portion of Tributary 0302 that is upstream of our drainage course. The other is within the '/. mile downstream corridor of the project. We have included the complaint on Tributary 0302 for reference as it shows that much of the erosion within this corridor is attributed to runoff that is directed onto the existing slopes, which are highly erodible. The drainage complaint within '/< mile of the project site is not really a complaint as it doesn't point out a specific drainage issue. It is our understanding that the property owner associated with this drainage complaint submitted a letter to the City of Renton as part of this projecYs hearing process. We have included a copy of this letter (Exhibit 11 from the Staff Report to the Hearing Examiner) along with the drainage complaints in Appendix B. The claim by the property owner is that trees are falling within the ravine due to the creek bed being washed out. If the existing trees are within the creek bed it is highly likely that they will eventually fall due to the streams natural erosion process. It is inevitable for a stream bed to erode over time and any tree roots within the stream bed will be exposed. It is important to note that as slides happen and other various blockages of the stream occur from fallen vegetation or other foreign objects, the stream will continue to correct itself over time. This may lead to additional slides within the ravine, but as stated above, this is the natural process of the stream itself For further detail please refer to the drainage complaints within Appendix B. As part of this Level 2 downstream analysis we mapped the contributing basin areas to Maplewood Creek , Tributary 0303 and Maplewood Creek Tributary 0302. We found that these basins are made up of a mixture of residential neighborhoods of various zoning, commercial properties, sensitive areas, drainage facilities, city streets, parks, and other various uses. The basins were mapped using a combination of LIDAR topography, King County Assessor Data, and the City of Renton's Surface Water Network map located on the City's website. The basin feeding Maplewood Creek Tributary 0303 is approximately 535 acres in size at the point where it enters the proposed project. The proposed project is slightly less than 13 acres in size or approximately 2 percent of the overall basin. At the point where Tributary 0303 joins - Tributary 0302 an additional 297 acres of basin area is added, which means the project is approximately 1 percent of the total area tributary to both drainage courses combined. At this point the downstream corridor is beyond the '/<mile downstream point from the project site. A Level 2 Downstream Analysis is a rough quantitative analysis of any downstream flooding, erosion or nuisance problems. It is evident from all of the public testimony and review of available data along with our site visit that issues surrounding the downst�eam drainage system are Severe Erosion Problems and not Severe Flooding Problems Quantifying an exact erosion problem is not something that can be calculated because erosion is caused by continually high peak flows over a period of time. It is not possible to equate the peak flows from this project site to the peak flows of the overall basin and make a determination that the flows from this project will increase erosion, as we cannot determine what the naturally occurring erosion-causing threshold is However, we can quantify what the overall basin area is and relate that to our proposed development Furthermore �ve can equate the flow control �tandards of this proiect to that of the existinq basin which are commonly acknowledged as being much less restrictive. As noted above the project area makes up only 2 percent of the overall basin tributary to Maplewood Creek. This project is utilizing the Flow Duration Standard Matching Forested Site Conditions. In a basin with a majority of the neighborhoods and/or developments providing various forms of sub-standard flow control; any flows directed to the downstream system from this project are insignificant compared to the existing condition. Even increasing the detention faci�ity requirements to the Flood Problem Flow Control Standard would not have any less impact to the downstream drainage system as this standard only additionally restricts the 100 year release rate which has no direct link to erosion problems. 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' � King County � Date:4H7/2014 Source:Kng CouMy iMAP-Property Informatan(http:pwww.metrokc.gov/GISlMAP) _ Off-Site Analysis Drainage Syste m Ta b l e OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE Surface Water Design Manual, Core Requirement #2 Basin: Cedar River Basin Subbasin Name: Lower Cedar River Basin Subbasin Number: Distance Observations of Field Inspector, Drainage Component Drainage Component from Site Existing Potential Resource Reviewer,or Symbol Type,Name,and Size Description Slope Discharge Problems Problems Resident Constrictions,under capacity,ponding, Type: sheet flow,swale,stream, overtopping,flooding,habitat or organism channel,pipe,pond;size, Drainage basin,vegetation,cover, destruction,scouring,bank sloughing, Tributary area,likelihood of problem, See Map diameter,surface area depth,type of sensitive area,volume % Ft. sedimentation,incision,other erosion overflow pathways,potential impacts A Stream Maplewood Creek Tributary 0 None None 0303 B Stream Maplewood Creek Tributary 0-3920 None None ' 0303 16834-Off-Site Malysis Drainage System Table.doc Upstream Basin Area Map : i 0 � ���, � � ���o � ; � ���� . ��1 � �� , o g ,. - �l� ,t=���r� �� �,� ��� ���_ y � , � : - - _ , __ `T,_ - _, . �� �- �-� _ - - c , '�'- _ l�, ," "; , �` � ,.., C� �� , �,, �� � ;. �) ' ��. i ���. �1 � _ � 1...�'� ° ; �k � . � � . � � --• ��,- ' � . .' � � � � p� p � . ��� ��� . � � _ � .- � _ I :. � .�/ '_ ( ��`� " r_1 �. .��/ �-_ - . � � ��. - _ _ �� � �~ h �� ' . 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I=\��� -- �-�_1_J ., i �: �, �. ., , � , � / � Nl_ 1 : . , ,�. / � i� �_ _. . �r �:.- , i ... . . _ _ �. . _ , , _ _ , r rI ` I . � I . . � LJ ., .•�--. -..� ._ ( �_ r- _� �_•'�. ; ;`i� l.�_� � I. _�1 , . � :._�, , I .�.... I .: �. r:� �� , , ` t ) . � `� `I / /�� . . e�y ..� . ,. , , ^. , '; i �. . �s '. .. .��,!J . � � � . .r � .._ . � � ., � � � ....... __.. �': ��I T1�' '-� .� Q r J ( I I I i ; . ��;� , -n J : �- �__._--- — _ - _ _. - l�� `) � �'y ��� �' ` :��r� _ _ __� - � � " _ � . . �. r � � . , ,--� , ,���_�-��'7�,�--� - _� � ��-�-�r�r1 � Tf T �.�T� 1 � � l�l_�-:� I i�� � "? ��-T -i rnr���`�� �-r-�V�-��: -�, ,<- >>,�- No. Do1a ey cwa. I�uu�. ee.�s�oo �oe N�moe. �GHAV� 0..�9�.a_� �`°"' For. Title: 18215 72ND AVENUE SOUTH QUADRANT HOMES UPSTREAM BASIN AREA MAP 16834 mP �Z KENT, WA 98032 ao,� �u_ „or:o��o� (425)251-6222 14725 SE 36TH ST. SUITE 100 � CneckeO�IL 1'.500' s�e.i � �-' ' (425)251-8782 FAX y �►►. ? "°°,°•°"-�"- °•."`°' BELLEVUE, WA 9808 sp . 0' CIVIL ENGINEERING. LANO PLANNING, N�p 1 n' � �l�N`ENG`NE�'Q SURVEYING, ENVIRDNMENTAL SERVICES Dot� t �� COPPERWOOD FI,..('�.\IiOI)Ua IIiM54\+Fhi��l I(iH_;q-". .��II�i,i.,�in IAuV'JHV Gul���iri��.11/lU,.'U14 I'."�Y.I'M ..n��. , C�i�LFIf���1�JIJ n�i�1� 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN A. Existing Site Hydrology This site is currently developed, with seven single-family residences containing eight tax parcels (152305-9066, 152305-9067, 152305-9201, 152305-9100, 152305-9093, 152305-9170, 152305-9043, and 152305-9221) and is currently zoned R4. The existing on-site improvements consist of storm and water utilities, and gravel driveways that access S.E. 2nd Place. There is a creek on site (Maplewood Creek Tributary 0303), near the east property line. The existing site drains to Maplewood Creek Tributary 0303, where it then leaves the site near the southeast corner. The existing discharge location will be maintained after development as well. It should be noted that along the existing frontage of S.E. 2nd Place approximately 150 feet west of Maplewood Creek Tributary 0303 there is an existing 12-inch culvert that crosses underneath the roadway from the north. This runoff is routed via ditch line along the northern boundary of the site to a 12-inch culvert just west of Maplewood Creek Tributary 0303 where it is discharged into the creek. In the developed condition his flow path will be maintained through the use of new catch basins with solid locking lids and new storm pipe that will connect the existing culver crossing underneath S.E. 2nd Place with the existing 12-inch culvert that discharges into the creek. Pre-Develoqed Basin: The Pre-Developed Basin can be broken down as follows: Total Basin Area = 9.9 Acres Modeled as Till Forest= 9.9 Acres The Pre-Develoqed Peak Rates are as follows: 2-year= 0.28 cfs 10-year= 0.48 cfs 100-year= 0.80 cfs B. Developed Site Hydrology The completed project will create 47 lots. The total developed area will be 9.9 acres in size. New impervious surfaces will include roadways, driveways, sidewalks, and roof areas. The project will be providing landscaped pervious areas, open space areas, and a drainage facility. A conveyance system consisting of catch basins and storm pipes will be constructed in the roadways to collect drainage from impervious surfaces and lots, and conveyed to the new drainage facility. A combination detention/wet pond will be constructed in Tract B to provide water quality and flow control for the project. The pond will contain a control structure fitted with a riser overflow. To satisfy the condition of approval to provide Enhanced Basic Water Quality, a StormFilter Vault using CSF media will be installed immediately downstream of the control structure. From there storm water will be conveyed to Maplewood Creek Tributary 0303 via a proposed 18-inch outlet pipe and riprap pad above the ordinary high water mark. The runoff will enter the creek and then be conveyed off site via Maplewood Creek. 16834.015.doc Post Developed Basin: The Post Developed Basin includes the developed basin area tributary to the new drainage facility. Individual Lot BMPs are required per the 2009 KCSWDM and 2010 City of Renton Amendments. Full Infiltration and Full Dispersion are not feasible due to the soil types and limited flow paths available. For purposes of sizing the onsite drainage facility we utilized the Reduced Impervious Surface Credit Individual Lot BMP. The R-8 zone allows for 75 percent max impervious surface per lot. For purposes of sizing the drainage facilities we reduced the allowable impervious coverage to 65 percent. The following list provides a basin area breakdown: Total Basin Area =9.81 Acres Till Grass Area = 3.94 Acres Impervious Area = 5.87 Acres Impervious Area Breakdown: Roads& P.A.T. = 1.63 Acres Lot Impervious Areas: 284,145 sf x 65% =4.24 Acres The Post Developed peak rates are as follows: 2-year= 1.77 cfs 10-year= 2.14 cfs 100-year= 3.61 cfs Bvpass Basin: The Bypass Basin includes a small area along the eastern portion of the S.E. 2nd Place frontage improvements. Due to the existing elevation of this section of road in relation to the maximum water surface elevation in the pond we are unable to route the runoff to the onsite pond. This area is accounted as bypass in the King County Runoff Time Series (KCRTS) detention facility sizing calculations because the post developed basin and bypass basin converge into the same drainage basin within '/4 mile downstream of the site. This basin includes 0.09 acres of impervious area. It should be noted that Water Quality Treatment is not required as there is less than 5,000 square feet of new impervious surface within in the Bypass Area. The detention facility has been sized to accommodate this bypass area. This bypass basin is to be collected and discharged directly to Maplewood Creek Tributary 0303 via a new 12-inch culvert placed above the ordinary high water mark at a 0.50 percent slope. The discharge velocity is below 5 fps so a 7- by 8-foot rock lined pad will be sufficient to prevent slope erosion. The Bvpass peak rates are as follows: 2-year=0.02 cfs 10-year=0.03 cfs 100-year= 0.04 cfs C. Performance Standards The KCRTS Runoff Time Series Program was used to size the detention facility. The detention pond was sized for the Flow Control Duration Standard Matching Forested Site Conditions based on the requirements of the 2009 KCSWDM and the 2010 City of 16834.015.doc Renton Amendments to the KCSWDM. Individual Lot BMPs are required as well. Full infiltration and Full Dispersion are not feasible due to the soil types and limited flow paths available. For purposes of sizing the onsite drainage faciliry we utilized the Reduced Impervious Surface Credit Individual Lot BMP. The R-8 zone allows for 75 percent max impervious surface per lot. For purposes of sizing the drainage facilities the allowable impervious coverage was reduced to 65 percent. D. Flow Control System The King County Runoff Time Series (KCRTS) Program was used to size the detention facility. Please refer to the KCRTS computations attached in this section. Based on the detention pond sizing calculations, the pond volume required is 110,677 cubic feet. The pond volume provided is 131,126 cubic feet. Overflow sizing calculations are also provided in this section. The pond will contain a control structure fitted with a riser overflow, a jail house grate, and an emergency overflow birdcage structure. The pond outfall will discharge onto a riprap pad sized according to the 2009 King County Surface Water Design Manual and 2010 City of Renton Amendments. The riprap pad will be 7.5 feet wide by 12 feet in length and 2 feet deep. The riprap pad will extend 1 foot above the crown of the 18-inch outlet pipe. The outfall velocity was calculated to be 4.59 ft/s using the 100 year emergency overflow flow rate of 3.61 cfs. Riprap pads are recommended for outfall velocities ranging from 5 ft/s to 10 ft/s, thus due to the conservative nature of this design erosion will not be a concern. The riprap pad will also be installed above the ordinary high water mark and will not negatively impact the existing creek flow. For further detail please refer to the Flow Master calculations in this section. Please refer to the pond sketch in this section for details E. Water Quality System The wet pond was sized to provide Basic Water Quality Treatment based on the requirements of the 2009 KCSWDM and 2010 City of Renton Amendments. Please refer to the wet pond sizing worksheet in this section for the wet pond sizing calculation. The wet pond volume required is 31,945 cubic feet. The wet pond volume provided is 38,949 cubic feet. In addition to the wet pond a StormFilter is immediately downstream of the control structure using cartridges of CSF to satisfy the Enhanced Basic Water Quality Treatment requirement. For further detail on the sizing of the StormFilter please refer to the sizing calculations provided by Contech within this section. Please refer to the pond sketch in this section for details 16834.015.doc Combination Wetpond/Detention Pond Volume Summary Project: Copperwood BCE Job# 16834 Detention Volume Required 110,677 Detention Pond Volume Summary Elevation (ft) Area (sf) Inc. Volume (cf) Total Volume (cf) 377 12,723 o a 378 14,335 13,529 13,529 379 16,004 15,169 28,698 380 17,729 16,866 45,564 381 19,510 18,619 64,184 382 21,348 20,429 84,613 383 23,243 22,295 106,90$ 384 25,194 24,218 131,126 Water Quality Volume Required 31,945 Detention Pond Volurne Summary Elevation (ft} Area (sf) Inc. Volume (cf) Total Volume (cf} 371 905 0 0 372 1,367 1,136 1,136 373 5,228 3,298 4,434 374 6,784 6,006 10,440 375 8,468 7,626 18,066 376 10,288 9,378 27,444 377 12,723 11,506 38,949 D Determining Number of C::NTECH Cartridges for Systems ENGINEERED SOLUTIONS Downstream of Detention CONTECH Stormwater Solutions Inc. Engineer: KET Date 11/3J2014 Site Information Project Name Copperwood Plat Project State Washington Project Location Renton Drainage Area,Ad 9.90 ac impervious Area, Ai 5.87 ac Pervious Area, Ap 4.03 % Impervious 59% Runoff Coefficient, Rc 0.58 Upstream Detention System Peak release rate from detention, Qrelease peak 2•29 �fs Treatment release rate from detention, Q�ease treat 0.18 cfs Detention pretreatment credit 50% (from removal efficiency calcs) Mass loading calculations Mean Annual Rainfall, P 36 in Agency required % removal 80% Percent Runoff Capture 90% Mean Annual Runoff,V, 679,562 ft' Event Mean Concentration of Pollutant, EMC 70 mg/I Annual Mass Load, M,o�i 2967.86 Ibs Filter System Filtration brand StormFilter Cartridge height 18 in Specific Flow Rate 1.00 gpm/ft2 Number of cartrldges-mass loading Mass removed by pretreatment system, M�e 1483.93 Ibs Mass load to filters after preUeatment, M�Ss� 1483.93 Ibs Estimate the required filter efficiency, Efi� 0.60 Mass to be captured by filters, Nl�i1e� 890.36 Ibs Allowable Cartridge Flow rate, (�rt 7.50 ' Mass load per cartridge, M�rt(Ibs) 36.00 Ibs Number of Cartridges required, N,�g 25 Treatment Capacity 0.42 cfs Determine Critical Sizing Value Number of Cartridges using Qrelease treat� Nfla,,,, 11 Method to Use: MASS-LOADING SUMMARY Treatment Flow Rate, cfs 0.42 Cartridge Flow Rate, gpm 7.5 Number of Cartridges 25 1of1 C=�'::NTECH� ENGINEERED SDEUTIONS Size and Cost Estimate ?repared by Kathryn Thomason on November 4, 2014 Copperwood Plat— Stormwater Treatment System Renton, WA Information provided: � Total contributing area = 9.90 acre • lmpervious area = 5.87 acre • Detention release rate, Qveat= 0.18 Cfs • Presiding agency= City of Renton, WA Assumptions: • Media = CSF cartridges • Cartridge Height = 18" • Per cartridge flow rate = 7.5 gpm • Drop required from inlet to outlet= 2.3' minimum Size and cost estimates: The StormFilter is a flow-based system, and therefore, is sized by calculating the peak water quality flow rate associated with the design storm. However, when the StormFifter is placed downstream o#detention the flow rate generated at the water quality storm is not always representative of the total volume of water that will go through the system or type of pollutant-loading the system may experfence in one year. ror this site, Contech Engineered Solutions LLC recommends using an 8x14 Peak Diversion StormFi(ter with 25 ,:artridges(see attached detail). The estimated cost of this system is 65 900, complete and delivered to the job site. This estimafe assumes that the vault is 7 feet deep. The final system cost will depend on the actual depth of#he unit and whether extras like doors ra#her than castings are specified. The contractor is responsible for setting the StormFilter and all extemal plumbing. Typically, precast StorrnFilters have internal bypass capacities of 1.8 cfs. 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SNOMONISN COUNTY � % �' KING COUNTY CJ i ''� b � � � P ' r E, t �� � � _ K �o J 1 � , ����I ' `� \ � 'i - � - �� � � � � : _� Q � _ ._� ;�-/ � .'a " � L � � � i e = �%- ER1M i t� -.- Say I - ; I � � ` I� � � _ _ _ °""h `_'���, � � I E E � _ `,�_ . ' \ C , ��-�,. � ,�,,,, , � - ', .Y� ;Z_ 1 `, �/'/� , r _ �(J\'/ � � /�1/'� GM � `S � - '�y ^, �. PON! .6. � EJ��� �� /� T, '� � ,�,� �;� �� o ri.a . (��, � �� .�,a f \ '.. � ' �� - - p` �---�� � � �i:� , ` p � . � ) _-' � / � / .�,a. \ � ' �, LANDSBURG Q �- 0 ( �, ...�� ,: � � ,, nma - e 1 Q - � n r��� �( ' ' ' \� �..� so��e —_ l qn Q � � �- �� ra `^�� r. C7 1 ; � � � � \ - '� � � � � D � . e � ' ST 1.1 � � =, - „ � , � o VIERCE COUNT♦ '\ - ST 1.0 ,� a Rainfall Regions and �o$ � � Q Regional Scale Factors �A o.s ,�.--�' �Tii Incorporated Area LA 1.0 LA 1.2 �e� River/Lake Major Road 1/9/2009 2009 Surface Water Design Manual 3-22 KCRTS Command CREATE a new Time Series � ------------------------ Production of Runoff Time Series Project Location : Sea-Tac Computing Series ; 16834pre.tsf Regional Scale Factor : �.00 Data Type : Reduced Creating Hourly Time Series File � Loading Time Series File:C:\KC SWDM\KC DATA\STTFbOR.rnf . Till Forest 9. 90 acres Total Area : 9.90 acres Peak Discharge: 0.799 CFS at 9:00 on Jan 9 in Year S Storing Time Series File: 1683�pre.tsf . Time Series Computed KCRTS Cammand CREATE a new Time Series ------------------------ Producticr_ of Runoff Time Series Project Location : Sea-Tac Co�rnuting Series : 16834dev.tsf Regional Scale Factor : 1.00 Data Type : Reduced Creating Hourly Tirne Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTG60R.rnf . Till Grass 3.94 acres Loading Time Series File:C: \KC SWDM\KC DATA\STEI60R.rnf . ?mpervious 5.87 acres -------------- Total Area : 9.81 acres Peak Discharge: 3 .b1 CFS at 6:00 on Jan 9 in Year 6 Stor�ng Time Series File:16834�ev.tsf _ Tir�e Series Computed KCRTS Command CREAT�, a netv Time Series ------------------------ Production of Runoff Time Series Project Location : Sea-Tac Computing Series : 16834bypass.tsf Regional Scale Factor : 1.00 Data Type : Reduced Creating Hourly Time Series File Loading Time Series File:C:\�C S�DM\KC DATA\STEI60R.rn- . Impervious 0.09 acres Total Area : 0.09 acres Peak Discharge: 0.043 CFS at 6:00 on Jan 9 in Year 8 Storing Time Series File: lo834bypass_tsf . Time Series Computed KCRTS Command eXit KCRTS Program ------------------ �Paused-Flow Freyuenry-KCRTS o O E3 � 0 Retum Period 2 5 10 20 50 100 ��� 0 16834rdoutpks in Sea-Tac ♦ 16834dsout.pks 0 16834dev.pks N 0 � p ♦ 4 p 0 U� 0 � o U m . v� �p� co t � � � R N � � � � . a 00 0 �o�' 1 2 5 10 20 30 40 50 60 70 80 90 95 98 99 CumuNative Probability �Pauxd-Duration Analysis-KCRTI o l�l LS ; n ° 16834rdout.dur o • 16834dsout.dur ♦ 16834tar.dur o � 0 I R � 0 � N � � o � m m � co t � y M ( D � i N O � O I O O 0 10 5 10� 10�3 10�2 10�� 1Q� Probabilit�r Ezceedence 3e�enticn/�etentior Fac-litv Type of Facility: Detenticr_ Po:.d Side Slope: 3.00 I::_V Pond Bottom Length: 155.00 �t Pond Bottom Widkh: 68.a0 =t Pond Bottom Area: 10540. sq. ft Top Area at 1 ft. FB: 23548. sa. ft 0.541 acres Effective Storage Depth; 7.00 ft Stage 0 Elevation: 377.00 ft Storage Volume: 1106?7. cu. ft �-- v�1�wtC. �eq,u:�`e�. 2.541 ac-f_ Riser Head: 7.00 ft Riser Diameter: 18.00 inches Number of orifices: 2 Full Head Pipe Orifice � Height Diameter Discharge Diameter {ft) {in) (CFS} (in) 1 0.00 1.50 0.161 2 4.90 3.00 0.354 6.0 Top Notch Weir: ncne Outflow Ratir.g C•.:rve: Kcne Stage Elevat'_en Stcrage Discharae Percolation Sur` Psea (ft} (ft) (cu. ft) (ac-ft) (cfs) (cfs} (sq. Tt) 0.00 377.00 0. 0.000 0.000 0.00 10540. �.02 377.02 211. 0.005 O.00B 0.00 10567. ! 0.03 377.03 317. 0.007 0.011 0.00 10580. , 0.05 377.05 529. 0.012 0.013 0.00 10607. O.Ob 377.06 635. 0.015 0.015 0.00 10620. 0.08 377.08 8�8. 0.019 0.017 0.00 10647. , 0.09 377.09 954. 0.022 0.019 0.60 Z0661. 0.11 377.11 1168. 0.027 0.020 0.60 10688. O.i3 377.13 1382. 0.032 0.022 O.QO 10715. 0.24 377.24 2568. 0.059 0.030 0.06 lOSb3. 0.36 377.36 3892. 0.089 0.037 0.00 11026. 0.48 377.48 5215. 0.120 0.042 0.00 1119_. 0.60 377.60 6567. 0.151 O.a47 0.00 11356. 0.72 377.72 7940. 0.182 0.052 0.00 11522. 0.84 377.84 4333. 0.214 0.056 0.00 11b89. 0.9& 377.96 10746. 0.247 0.060 0.00 11858. 1.07 378.07 Z2058. 0.277 0.063 0.00 12013. 1.19 378.19 Z3510. 0.310 0.067 0.00 12183. 1.31 378.31 14982. 0.344 0.070 0.00 12355. 1.43 378.43 16475. 0.378 0.073 0.00 12527. 1.55 378.55 17989. 6.413 4.07b 0.00 12700. 1.67 378.67 19523. 0.448 0.079 0.00 12875. 1.79 378.79 21079. 0.484 0.082 0.00 13050, 1.90 378.90 22523. 0.517 0.084 0.00 13212. 2.02 379.02 24119. 0.554 0.087 0.00 13390. 2.14 379.14 25737. 0.591 0.089 0.00 13568. 2.26 379.26 27376. 0.628 0.092 0.00 13748. 2.38 379.38 29036. 0.667 0.094 Q.00 13928. 2.50 379.50 30719. 0,705 0.096 0.00 14110. 2.62 379.62 32423. 0.744 0.099 0.00 14293. 2.74 379.74 34149. 0.784 0.101 0.00 14476. 2.85 379.85 35751. 0.921 0.103 0.00 14646. 2.97 379.97 37519. 0.861 0.105 0.00 14831. 3.09 380.09 39310. 0.902 0.107 0.00 15018. � 3.21 380.21 4I124. 0.944 0.109 O.OQ 15206. 3.33 380.33 42960. 0.986 0.111 0.06 15395. 3.45 380.45 44819. 1.029 0.113 0.06 15585. 3.57 380.5? 46700. 1.072 0.115 0.00 15775. 3.68 38d.68 48445. 1.112 0.117 0.00 15951. 3.86 380.80 50371. Z.156 0.119 0.00 16144. 3.92 380.92 52320. 1.201 0.121 0.00 16338. 4.04 381.04 54292. 1.246 0.123 0.00 16533. 4.16 381.16 56288. 1.292 0.124 0.00 16729. 4.28 381.28 58307. =.339 0.126 O.OQ 16926. 4.40 381.40 60350. ?.385 0.128 0.00 17124. 4.51 381.51 fi2244. 1.429 0.130 0.00 17307. 4.63 381.63 64333. 1.477 O.I31 0.00 17507. 4.75 381.75 66445. 1.525 O.Z33 Q.00 17708. 4.87 381.87 68582. 1.574 0.135 0.00 1791Q. 4.90 381.90 69120. 1.587 0.135 0.00 17961. 4.93 381.93 69660. 1.599 0.13B 0.00 18�11. 4.96 381.96 70241. I.612 0.145 0.00 18062. 4.99 381.99 70744. 1.624 0.157 0.00 18113. 5.03 382.03 71470. 1.641 0.173 0.00 18181. 5.06 382.06 72016. _.653 0.193 0.00 18232. 5.09 382.49 72564. 1.666 0.217 0.00 18283. 5.12 382.12 73113. 1.678 0.243 0.00 18334. 5.15 352.15 73664. 1.691 0.261 0.06 18386. 5.27 382.27 7�882. 1.742 0.288 0.00 18591. 5.39 382.39 78126. 1.794 0.312 �.Od 18798. 5.51 382.51 80394. 1.846 0.333 0.06 19005. 5.62 382.62 82495. 1.894 6.353 0.00 19147. 5.74 382.74 84811. 1.947 0.370 0.00 194Q6. 5.86 382.86 871�2. 2.001 0.387 0.00 19617. 5.98 382.98 89519. 2.055 G.403 0.00 19824. 6.20 383.10 91911. 2.110 0.418 0.00 20041. ' 6.22 383.22 94329. 2.165 0.432 0.00 20255. 6.34 383.34 96773. 2.222 0.446 0.00 20470. i 6.46 383.46 99242. 2.278 0.459 0.00 20685. i 6.57 383.57 101528. 2.332 0.472 0.00 20885. 6.69 383.69 104047. 2.389 0.485 0.00 21102. 6.81 383.81 106593. 2,447 0.497 0.00 21321. 6.93 383.93 109165. 2.506 0.508 0.00 2154Z. 7.00 384.40 110577. 2.541 0.515 0.00 21670. 7.10 384.10 112$53. 2.541 0.987 O.QO 21855. 7.20 384.20 115C48. 2.641 1.840 0.00 22040. 7.30 384.30 117261. 2.692 2.940 0.60 22226. 7.40 384.40 119493. 2.743 4.250 0.00 224'_3. 7.50 384.50 121744. 2.795 �.730 0.00 22600. 7.60 384.60 124013. 2.847 7.160 0.00 22788. 7.70 384.70 126301. 2.899 7.700 Q.00 22977. 7.80 384.80 128609. 2.952 8.200 0.00 23167. 7.90 384.90 130935. 3.006 8.670 0.00 23357. 8.00 385.00 133280. 3.060 9.110 O.flO 23543. 8.10 385.10 135644. 3.114 9.540 0.00 237�0. 8.20 385.20 138028. 3.169 9.940 0.00 23932. 8.30 385.30 14Q431. 3.224 10.330 0.00 24'�25. 8.40 385.40 142853. 3.279 10.700 0.00 2a319. 8.50 365.50 145295. 3.336 Z1.060 0.00 24514. 8.60 385.60 147756. 3.392 i1.410 0.00 24709. 8.70 385.70 150237. 3.449 11.750 0.00 24905. 8.80 385.80 152737. 3.50b 12.080 0.00 25102. 8.90 385.90 155257. 3.564 12.400 0.00 25306. Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) {Ac-Ft) 1 3.61 2.29 7.24 384.24 115953. 2.662 2 1.77 0.51 7.00 384.00 110618. 2.539 3 2.14 0.44 6.27 383.27 95387. 2.196 _ 4 1.78 Q.44 6.31 383.31 96209. 2.209 ' S 1.88 0.33 5.46 382.48 79889. 1.834 6 1.11 0.17 5.03 382.03 71404. 1.639 7 Z.43 0.13 4.44 381.44 61047. 1.401 8 1.54 0.11 3.26 380.26 41959. �.963 Hyd R/D Facility Tributary Reservoir POC Outflcw Outflow Inflow Inflow Target Calc 1 2.29 6.04 ******** ******* 2.31 2 0.51 o.aa ******** 0.63 0.52 3 0.44 O.Q3 ******** ******* 0.44 fe - �� ��Ca�r 4 0.44 0.02 ******** ******* 0.45 5 0.33 Q.02 ******** ******* 0.33 6 0.17 6.01 ******** �*+**** 0.17�irr-�' �-^ YCO'� 7 0.13 0.02 ******** **�**** 0.13 8 0.11 0.02 *x****** **�**** 0.12 ---------------------------------- Route Time Series through Facility � Inflow Time Series File:I6834dev.tsf Outflow Time Series File:16834rdout POC Time Series File:lb834dsout Inflow/Outflow Analysis Peak Inflow Di.scharge: 3.b1 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 2.29 CFS at 10:00 on Jan 9 in Year 8 Peak Reservoir Stage: 7.24 Ft Peak Reservoir Elev: 384.24 Ft Peak Reservoir Storage: 115953. Cu-Ft . 2.062 AC-Ft Add Time Series:16834bypass.tsf Peak Summed Discharae: 2.30 CFS at 10:00 on Jan 9 in Year 8 Point of Compliance File:16834dsout.tsf Flow Frequency Analyeis Ti:ne Series File:16834rdout.�sf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob iCFS) (CFS) (ft) Period 0.660 2 2/09/O1 20:00 2.2° 7.24 1 100.00 0.990 0.130 7 1/07/02 4;00 0.6b� 7.03 2 25.OQ 0.960 G,438 4 3/06/03 22:00 0.443 6.31 3 10.00 6.900 ' �.110 B 8/26/04 7:00 0.438 6.27 4 5.Q0 0.800 �.172 6 1/08/05 3:00 0.328 5.48 5 3.00 0.667 �.328 5 1/19/06 O:CO 0.172 5.03 6 2.00 0.500 �.443 3 11/24/06 B:^u0 Q.130 4.49 7 1.30 0.231 2.29 1 1/09/08 10:00 0.J.10 3.26 S 1.16 0.091 Computed Peaks 1.75 7.19 50.Ot} 0.980 Flow Frequency Analysis Time Series File:16834dsout.tsf p���� pG (`��t,wnCG Pro;:ect Location:Sea-Tac ---Annual Pea3c Flow Rates--- -----F1ow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob {CFS) (CFS) Period 0.654 2 2/09/O1 20:00 2.31 1 7.00.00 0.990 0.133 7 1/66/02 3:00 0.664 2 25.00 0.960 6.441 4 3/bb/03 21:00 O.e46 3 10.fl0 0.900 G.?22 8 S/2b/�4 2:00 0.�41 4 5.00 0.800 0.173 6 1/Ofi/05 3:OG 0.330 5 3.00 0.667 0.330 5 1/18/66 23:00 0.173 6 2.00 0.500 0.446 3 11/24/06 7:04 0.133 7 1.30 0.231 2.31 1 1/09/OB 10:00 0.122 8 1.10 0.091 Comp��ted Peaks 1.76 50.00 0.980 F1ow Duration from TiTe Series File:lb834rdout.tsf Cutoff Count Frequency CDF Sxceedence_Probability Cws � � $ u.009 32532 53.053 53.653 46.947 0.469E+00 �.028 6671 10.879 63.932 36.C68 0.361E+00 0.047 6012 9.864 73.736 26.264 0.263E+00 0.065 5202 8.483 82.220 17.780 0.17BE+00 0.084 4840 7.893 90.113 9.887 0.989E-01 0.102 2452 3.999 94.111 5.889 0.589E-01 0.121 1928 3.144 97.255 2.745 0.274E-01 0.139 1299 2.118 99.374 0.626 0.626E-02 0.158 42 0.668 99.442 0.558 0.558E-42 0.177 42 0.668 99.511 0.489 0.4898-02 0.195 21 0.034 99.545 0.455 0.455E-02 0.214 13 0.�21 99.566 0.434 0.434$-02 0.232 14 0.023 99.589 0.411 0.411E-02 0.251 9 Q.015 99.604 0.396 0.396g-02 0.269 21 0.034 99.638 0.362 0.362E-02 4.288 37 0.060 99.698 0.302 0.3025-02 0.307 21 0.034 99.733 0.267 0.267E-02 0.325 30 0.049 99.761 0.219 0.219E-02 0.344 22 0.036 99.617 0.183 0.183E-02 0.362 12 0.020 99.837 0.163 0.163E-02 Q.381 15 0.024 99.861 0.139 0.1395-02 6.399 14 0.023 99.884 0.116 Q.116E-02 0.418 14 0.023 99.907 0_493 Q.930E-03 0.437 16 0.026 99.933 0.067 Q.669E-03 0.455 15 0.024 99.958 0.042 0.424E-03 �.474 10 0.016 99.974 0.026 0.261E-03 0.492 4 0.007 99.980 0.020 0.196E-03 0.511 7 0.011 99.992 0.008 0.815E-04 0.529 3 0.005 99.997 0_003 0.326�-04 ��,548 0 0.000 59.997 0.403 0.326E-04 0.567 D 0.000 99.997 0.603 0.326E-04 ��.585 0 0.060 99.997 0.603 0.326E-04 0.604 1 O.OQ2 99.998 0.602 0.163fi-04 0.622 0 O.OQO 99.998 0.002 0.163E-04 0_641 0 O.OQO 99.99B 0.002 0.163E-64 0.659 0 0.000 99.998 0.062 0.163E-C4 Flow Duration from Time Series File:16834dsout.tsf Cutoff Count Frequency CD? Exceedence_probability CFS � � g 0.609 32521 53.035 53.035 46.965 0.470E+00 0.028 6595 10.755 63.790 36.210 0.362E+0�� 0.047 6040 9.850 73.640 26.360 0.264E+G�� 0.066 5142 8.386 82.025 17.975 0.180E+00 0.084 4690 7.975 90.afl0 10.000 O.100E+00 0.103 2487 4.056 94.056 5.944 0.594E-�1 0.122 1913 3.120 97.175 2.825 0.282E-01 0.140 1330 2.169 99.344 0.6�6 0.656E-0�: ��.159 63 0.103 99.447 0.553 0.553E-0� 0.178 39 O.Q64 99.511 0.489 0.489E-G� 0.196 21 0.034 99.545 0.455 0.455E-G:�. 0.215 14 0.023 99.568 0.432 0.432E-0:' ' 0.234 13 0.021 99.589 0.411 0.411E-0� �5� In n,ni� qc �n� n ,�g� O.�q�•_ 0.271 20 �.�33 99.638 G.362 0.362E-02 fl.290 36 C.�59 99.697 0.303 0.303E-02 0.308 22 C.036 99.733 0.267 0.267E-07. �.327 32 0.052 99.785 0.215 0.215E-02 0.346 20 0.033 99.817 0.183 0.183E-02 0.364 12 0.020 99.837 0.163 0.163E-0? 0.383 15 0.024 99.861 6.139 0.139E-C� 0.402 13 0.021 99.883 0.117 0.117E-C� 0.421 14 0.023 99.905 0.095 0.946E-03 0.439 15 0.024 99.930 0.070 0.701E-03 0.458 I7 0.028 99.958 0.042 0.424E-03 0.477 9 0,015 99.972 0.028 0.277E-0� 0.495 5 0.008 99.480 0.020 0.196E-0.-� 0.514 7 0.011 99.992 0.0�8 0.815E-Ot 0.533 3 O.Q05 �9.957 0.0��3 0.326E-C�1 0.551 6 O.Q00 99.947 O.D03 0.326E-C� 0.570 0 0.000 99.997 0.003 0.326E-C4 0.589 0 0.000 99.997 0.003 0.326E-0�1 0.607 1 0.002 99.998 0.002 0.163E-04 0.626 0 4.000 99.998 0.002 0.163E-0� 0.645 0 0.000 99.998 0.002 0.163E-04 0.653 0 0.000 99.958 0.0�2 0.163F.-C�t Duration Comparison Anayi., Base File: 16834pre.ts' New File: 16834dsout. Cutoff Units: Disc^arge i__ _.:� -----Fraction o*" Tir.i2----- ---------Check of Tolerance------- Cutoff Base New °sChange Prob�bility Base New gChange 0.140 I 0.91E-02 G.6bE-02 -27.3 � 0.91E-02 0.140 0.135 -3.7 0.177 � 0.62E-�2 0.49E-02 -20.8 � 0.62E-02 0.177 0.145 -18.3 0.214 � 0.48�-02 Q.43E-62 -9.8 j 0.48E-02 0.214 0.185 -13.6 0.252 � 0.363-02 0.40E-02 9.9 1. 0.36E-02 0.252 0.270 7.3 0.289 � 0.28E-02 0.30E-02 7.5 j 0.28E-02 0.289 0.301 4.Q 0.326 � 0.22E-02 0.22E-02 1.5 i 0.22E-02 0.326 0.327 0.2 0.363 I 0.15E-02 0.16E-02 13.5 � 0.15E-02 0.363 0.380 4.5 0.401 I 0.998-03 0.128-02 19.7 � 0.99E-03 0.401 0.417 4.1 0.438 I 0.62E-03 0.72E-03 15.8 � 0.62E-03 0.438 0.442 0.8 0.475 � 0.34E-03 0.285-63 -19.0 � 0.34E-03 0.475 0.467 -]..7 0.513 ! 0.21E-03 0.98E-G4 -53.8 � 0.21E-03 0.513 0.493 -3.9 0.550 � 0.16E-03 0.33E-04 -80.0 � 0.16E-03 0.550 0.501 -8.9 0.587 � 0.98E-04 0.33E-04 -66.7 � 0.98E-04 0.587 0.513 -12.7 0.624 � 0.16E-04 0.168-04 0.0 I 0.16E-�4 0.624 0.664 6.3 Maximum positive excursion = 0.021 cfs { 8.2$} occurring at 0.256 cfs on the Base Data:16834pre.tsf and at 0.277 cfs on the New Data:16834dsout.tsf Maximum negative excursion = 0.036 cfs (-19.3�) occurring at 0.169 cfs o*� the Base Data:lb834pre.tsf and at 0.152 cfs on the New Data:16834dsout.ts� 16834pre.pks I Flow Frequency Analysis I Time Series File:16834pre.tsf P�� `��`�o�R' Project �ocation:Sea-Tac ---Annual Peak F1ow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peal<s - - Rank Return Prob (CFS) (CFS) Period 0.625 2 2/09/O1 18:00 0.799 1 100.00 0.990 0.17Q 7 1/06/02 3:00 0.625 2 25.00 0.960 Q.463 4 2/28/03 3:00 0.480 3 10.00 0.900 U.016 8 3/24/04 20:00 0.463 4 5.00 0.800 0.275 6 1/05/05 8:00 0.404 5 3.00 0.667 0.480 3 Z/18/06 21:00 0.275 6 2.00 0.500 0.404 5 11/24/06 4:00 0.170 7 1.3Q 0.231 0.799 1 1/09/08 9:d0 0.016 8 1.10 0.091 Computed Peaks 0.741 50.00 0.980 Page 1 16834bypass.pks Flow Frequency Analysis Ti me Seri es Fi 1 e:16834bypass.tsf Qj�PaSS ProjeCt LOCation:5ea-Tac ---Annual Peak Flow Rates--- -----Flo�v Frequency Analysis------- Flow ►zate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.022 7 2/09/O1 2:00 0.043 1 100.00 0.990 0.�19 8 1/OS/02 16:00 0.033 2 25.00 0.960 0.027 3 12/08/02 18:00 0.027 3 10.00 0.900 0.0�2 6 8/26/04 2:00 0.027 4 5.00 0.800 0.027 4 10/28/04 ].6:00 0.023 5 3.00 0.667 0.023 5 1/18/06 16:00 0.022 6 2.00 0.500 0.033 2 10/26/06 0:00 0.022 7 1.30 0.231 0.043 1 1/09/08 6:00 d.019 8 1.10 0.091 Camputed Peaks 0.039 50.00 0.980 i �, '. ,! � Page 1 16834dev.pks Flow Frequency Analysis Ti me se ri es Fi 1 e:16834dev.tsf O���P��' Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- F1oUr Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 1.77 6 2/09/O1 2:00 3.61 1 100.00 0.990 1.43 8 1/05/0� 16:�0 2.23 2 25.Od 0.960 2.].4 3 2/27/03 7:00 2.14 3 10.00 0.900 1.54 7 8/26/04 Z:00 1.88 4 5.00 0.800 1.85 5 10/28/04 16:00 1.85 5 3.00 0.667 1.88 4 1/18/06 16:00 1.77 6 2.00 0.500 2.23 2 10/26/06 0:00 1. 54 7 1.30 0.231 3.61 1 1/09/08 6:00 1.43 8 1,10 0.091 Computed Peaks 3.15 50.00 0.980 Page 1 16834rdout.pks I� Flow Frequency Analysis �� p��lt Time series File:16834rdout.tsf � Project Location:Sea-Tac , ---annual �eak Flow Rates--- -----�low Frequency Analysis------- Flo�a Rate Rank Time af Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0.660 Z 2/09/O1 20:00 2.29 7.24 1 100.00 0.990 0.130 7 1/07/02 4:00 0.660 7.03 2 25.00 0.960 0.438 4 3/06/03 22:00 0.443 6.31 3 10.00 0.9fl0 4.110 8 8/26/04 7:00 0.438 6.27 4 5.00 0.800 0.172 6 1/08/05 3:00 0. 328 5.48 5 3.00 0.667 0.328 5 1/19/06 0:00 0.172 5.03 6 2.00 0.500 ', 0.443 3 11/24/06 8:00 0.130 4.49 7 1.30 0.231 2.29 1 1/09/08 10:00 0.110 3.26 8 1.10 0.091 Computed Peaks 1.75 7.19 50.00 0.980 Page 1 16834dsout.pks Flow Frequency Analysis Ti me seri es Fi 1 e:16834dsout.tsf Qo;��- v�C �.omQ1�o.n�� Project Location:5ea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (C FS) (CFS) Pe ri od 0.6G4 2 2/09/O1 20:00 2.31 1 100.00 0.990 0.133 7 1/06/02 3:00 0.664 2 25.00 0.960 0.441 4 3/06/03 21:00 0.446 3 lO.OQ 0.900 0.122 8 8/26/04 2:00 0.441 4 5.00 0.800 Q.173 6 1/08/OS 3:00 0.330 S 3.00 0.667 0.330 S 1/18/06 23:00 0.173 6 2.00 0. 500 0.446 3 il/24/06 7:00 0.133 7 1.30 0.231 2.31 1 1/09/08 10:00 0.122 8 1.10 0.091 Computed Peaks 1.76 50.00 0.980 Page 1 Jailhouse Window Sizing Date: 10/6/2014 BCE Project No.: 16834 ProjecF: Copperwood Per Figure 5.3.4.E King County Q=C(L-0.2H)H�` Drainage Manual 2009 Where: Q=flovl(cfs)=C(L-0.2H) H�= 3.97 cfs {Allowable Flow) C=3.27+0.4 F!/Y{ft)= 3.30 ft H=hydraulic head(ft)- 0.50 ft P=distance from outflow pipe to overfloar elevatlon(ft)= 7.00 ft L=circumference length(ft)= 3.50 ft D=inside diamter(ft) = 4.50 ft 100yr Peak Flow= 3.61 cfs Peak Flow < Allowable Flow (OK) Jailhouse Widow Size= 3.50 ft. long x 0.50 ft. htgh � riser H - � D L - P -�--- PLAN VIEW NTS SECTION NTS 53.4 CONTROL STRUCTURES—MBTNODS OF ANALYSIS Riser Overflow The nomograph in Figure 5.3.4.H may be used to determine the head(in feet)above a riser of given diameter and for a given flow(usvally the 100-year peak flow for developed conditians). ; FIGURE 5.3.4.H RISER INFLOW CURVES I �o0 72 54 48 42 36 I 33 30 27 I 24 � 21 = s � � ,a � �. � 10 15 W w � - � � ... d 12 10 � 1 0.1 HEAD IN FEET(measured from crest of riser) �p Q,,,,,�=s.739 DH'n Control Structure Riser Qo�i�e3.782 D�H�n Q- 3.61 CFS Q In cfs,D and H in feet D= 18in Slope change occurs at we(rvorifice transitio� H_ 0.39 FT 2009 Surface Water Design Manual 1/9/2009 5-47 53.4 CONTROL STRUCTURES—METHODS OF ANALYSIS Riser Overftow The nomograph in Figure 5.3.4.H may be used to determine the head(in feet)above a riser of given diameter and for a given flow(usually the I00-year peak flow for developed conditions). FIGURE 53.4.H RISER INFLOW CURVES 100 72 54 48 42 36 � 33 ' 30 27 I 24 � 21 � � I � 18 � � � i0 15 w w � � � ... d 12 10 1 0.1 HEAD IN FEET(measured from crest oi riser) �� aw.��.739 DH� Emergency Over Flow q,�n�,a3.782 D�H�n Q- 3.61 CFS Q In cfs,D and H in feet D= 48in Slope change occurs at welr-orffice transition H= 0.21 FT 2009 Surface Water Design Manual 1/9/2009 5-47 �, Wetpooi Sizing Worksheet � � 6.4.1 WETPONDS—BASIC AND LARGE—METHODS OF ANALYSIS FIGURE 6.4.1.A PRECIPITATION FOR MEAN ANNUAL STORM IN INCHES(FEE'1� ST 1.0/ �A � 2 ST 1.1 ST 1.0 LA 0.8 LA. 0.9 �A.�„'��„�,��,. � , q ■i�n eou�rr i \� -I `� e t � a a �,� '- ' �' B .Q� � " + cNku �.' e,� � �„ ,,,, i : f' wa _ T I � �� � �' I � �i� wa�� � � •�' • � 0 %� 1 .e.r 'S cwoan \ � / Q � Q 1 r.� � s�oa Q ;�7 r _ • �' n a' r � � - - r 0.54" � -, � � (0.045') b �1[IICE COtl�ff 0.47" � (0.039') � • �_TI_7 Incorporated Area �� ' .� RivBdLake 0.4 7" — Major Road (0.039') p,5 2� (0.043') 0.65" NOTE:Areas east of the eastemmost isopluvial should use 0.65 0.56" (0.054') inches unless raintall data is availabie for the location of interest (0.047') result,generates large amounts of runoff. For this application,till soil types include Buckley and bedrock soils,and alluvial and outwash soils that have a seasonally high water table or are underlain at a shallow depth(less than 5 feet)by glacial rill. U.S. Soil Conservation Service(SCS)hydrologic soil groups that are classified as till soils include a few B,most C,and all D soils. See Chapter 3 for classification of specific SCS soil types. 2009 Surface WaterDesign Manual 1/9/2009 6-71 Wetpool Sizing Worksheet Summary of the 2009 SuAace Water Design Manual Requiremenfs Project Name: �;���;��e��,�.�c���i Project Number: I�:�3:���1 Step 1) Determfne volume factor f. Basicsize............................................. f= 3 Large size............................................. f= 4.5 Step 2)Determine rainfall R for mean annual Storm Detemine rainfall R for mean annual storm Rainfall................................................. O.U3J (feet) Step 3)Calculate runoff from mean annual storm V,_ (0.9Ai +0.25A�9+0.10A,�+O.a 1 Aa9) X R A;=tributary area of impenrious surface 255,697 (sfl A,9=tributary area of till grass 171,626 (sfl A�=tributary area of till forest 0 (sf) Ao9=tributary area of outwash grass 0 (s� R= rainfall from mean annual storm 0.039 (feet) V�=Volume of runoff from mean annual storm 10,648 (cfl Step 4)Calculate wetpool Volume Vb=fV� f=Volume Factor 3 Vr=Volume runoff, mean annual atorm 10,648 (cfl Vb=Volume of the wetpool 31,945 (cf) Step 5) Determine wetpool dimenslons a) Determine geometry of first cell Volume in first cell 9,583 (cfl Depth h 1 st cell (minus sed. Storage) 7 (feet) Determine horizontal xs area at mid-depth using 1,369 (s� A mid=Vol. 1 st cell/h Mid-width 37 (feet) Mid-length 37 (feet) Determine xs area at surface Z=Side slope length (_H:1� 3 3:1 recommended 2(h/2 x Z)= 21 (feet) Dimensions of top of pond adjusted for geometrics Top width 58 (feet) Top length 58 (feet) Area of Top 3364 (feet) b) Determine geometry of second cell Volume in second cell 22,36i (cf} Depth h 2nd cell 4 (feet) Determine xs area at mid-depth using 5,590 (sf) A mid=Vol. 2nd cell/h Mid-width 37 (feet) Mid-fength 151 (feet) Determine horizontal xs area at surface Z=Side slope (ength {_H:1 V} 3 3:1 recommended 2(h/2 x Z}- 12 �feet) Dimensions of top of pond adjusted for geometrics Top width 49 (feet) Top length 163 (feet) Area of Top 7991 (feet} Adjustment to celfs (if necessary) Geometry check: Overall pond L:W at mid-depth = 3:1 Pond width (mid-depth) 37 Cell 1 length (mid-depth} 37 Cell 2 length (mid-depth) 151 Pond Length (mid-depth)=Cell 1 +Cell 2 188 L mid : W mid = 5.08 Total Wetpond Surface area required = 11,356 3,733 � � � � � U C6 U � a� � � c� � � 0 � OUTFALL PIPE FLOW VELOCITY SIZED FOR 100-YR - �.: — _.-- --.,�__._ .� ��Worksheet:CircularPipe-1 ��_0_I�� UNiorm Fbw (�eduey Vxkd Flow J Measeyes Sdve For: ��Oe� � � Frldian Methat �F�� � ROU�f1ESsC0E1fiCIG�t 0.012 O �W'�'��: 079 �a Cherml Slope: 0.00550 1tM JYelted Perineter. 2.23 a Normd Deptk 0.69 ft Hydraic Rariu: 0.35 n Diemder: 1.50 � T�p�h� 1.49 n ��� 3.61 fl•ls Gidcal Depth: 0.73 � L 10�`t r �iq�. �►�«,c F� as.� � 'F 1o'^J �, �,c r a�ed�.or,�e: o.004s� +t►a F.i++u�c �G� fi��••- veiodtY aSs tus FI�w `b'�Y"°°�: o.� n �, Speciflc Ener9Y 1.01 ft � Fradal�Mniber: �.�� Me�un.rm Diuhxgx � 9.08 tt'� dscharge Flt 8.44 ft'� Slope Fut 0.007 07 � Flow Typa ` c�p���� \� I�TT�II �'C.i1�i��T � 8 Celd,tdiorl SucceaShl. ���. �� .��, L �.� rt►� =? ���►� 1���� 'q ��t��, �. . �� �_�;, �x;v' }�,u� j�,,:Fe,,_., '�.,i`h,r, '�1�;�;,, W',1� � �� Zn;k�, L� ,r;f,�.��,� Q�r ��L��h� 5,,��,cG W��� '(�cs5n P'�.nvAl �Z�i� . 7,.5' w:� � IZ' �ohg w 2 ' 1��P . � a K:P'�W' �c d2 �"O �x�i�2 � ��C: �(`c?Wrt e� �:�Pt_'. Copperwood Outfall Project Description FricGon Method Manning Formula Solve For Normal Depth Input Data Roughness Coefficient 0.012 Channel Slope 0.00550 fUft Diameter 1.50 ft Discharge 3.61 ft'!s Results Normal Depth 0.69 ft Flow Area 0.79 ft' Wetted Perimeter 2.23 ft Hydraulic Radius 0.35 ft Top Wdth 1.49 ft Critical Depth 0.73 ft Percent Full 45.7 % Critical Slope 0.00451 ft!ft �l .I Velocity 4.59 ftls -�-____ /nn � V�.�u:_. �y Velocity Head 0.33 ft Specific Energy 1.01 ft Froude Number 1.11 Maximum Discharge 9.08 ft'/s Discharge Full 8.44 ft'!s Slope Full 0.00101 ft/ft Flow Type SuperCritical GVF Input Data DownsVeam Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % NoRnal Depth Over Rise 45.70 % Downstream Velocity Infinity ft/s Bentley Syatems,ine. Haeetad Methoda SaB�Mk�61drAAaster V81(SELECTserles 1) [08.11.01.03] 416/20161:45:12 PM 27 Siemons Company Drive 5uite 200 W Wetertown,CT 06795 USA +1-203-755-1666 Page 1 of 2 Copperwood Outfall GVF Outpuf Data --_ _ _ _ � = \ _ ' Upstream Velocity Infinity ft/s Normal depth 0.69 R Criticat Depth 0.73 ft Channel Slope 0.00550 ft/ft Critical Sfope 0.00451 �,'ft Bentley Systems,Inc. Haestad Methods So�dfe�EtdarMaster VBi(SELECTseries 1) [08.11.01.03] 4!6/2015 1:45:12 PM 27 Slemons Company Drive Suite 200 W Watertown,CT 06795 USA +1-203-755-1666 Page 2 of 2 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN The on-site conveyance system was designed in accordance with the 2009 KCSWDM. The proposed conveyance system for this project is curb, gutter, catch basins, and storm drainage pipe. The majority of the storm drainage pipe used will consist of smooth-walled corrugated polyethylene pipe with a Manning's roughness coefficient design value of 0.014. , 100-year conveyance calculations for the pipes have been completed using the Rational Method as shown on the enclosed Excel spreadsheet. The following are the parameters used in design of the pipes , 1. A Runoff Coefficient — 'C' value was calculated from the 2009 KCSWDM for each tributary ' area pursuant to table 3.2.1.A. �� � 2. A 100-yearl24-hour precipitation of 3.9 inches in accordance with Figure 3.2.1 D. II'� 3. A starting time of concentration of 6.3. 4. An "n"factor of 0.014. (0.012 for Backwater Analysis) The tributary areas have been calculated to each of the catch basins connecting to the proposed piping system, as shown on the enclosed map. A 100-year backwater analysis to determine the hydraulic grade line and to see if any catch basin rims overtop has also been performed using KCBW in accordance with the 2009 KCSWDM and the 2010 City of Renton Amendments to the KCSWDM. Please see the attached calculations in this section. � i , i 16834.015.doc 16834-Conveyance.xls BARGHAUSEN C�NSULTING ENGINEERS-PIPE FLOW CALCULATOR using the Rational Method&Manning Formula CITY OF RENTON DESIGN FOR 100 YEAR STORM JOB NAME: COPPERWOOD NOTE:ENTER DEFAULTS AND STORM DATA BEFORE BEGINNING JOB#: 16834 DEFAULTS C= 0.64 n- 0.014 REVISED: 2/10/2015 d= 12 Tc= 6.3 A=Contributing Area(Ac) Qd=Design Flow(cis) COEFFICIENTS FOR THE RATIONAL METHOD"Ir"-EQUATION C=Runoff Coefficient Qf=Full Capacity Fiow(cfs) STORM Ar Br T�Time of Concentration(min) Vd=Velociry at Design Flow(fps) 2YR 1.58 0.58 1=Intensiry at Tc(in/hr) Vf=VeloCity at Full Flow(ips) t 0YR 2.44 0.64 PRECIP= 3.9 d=Diameter of Pipe(in) s=Slope of pipe(%) 25YR 2.66 0.65 Ar= 2.61 L=Length of Pipe(ft) n=Manning Roughness Coefficient 50YR 2.75 0.65 Br= 0.63 D=Water Depth at Qd(in) Tt=Travel 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 Qd Qt Qd/Qf D/d D Vf Vd Tt CB1i29 CB828 0.09 2.18 76 12 8.3 0.014 0.64 0.09 0.06 0.06 3.19 0.1 B 4.88 0.038 0.137 1.64 622 2.97 0.43 CB#28 CBif26 O.U3 1.00 119 12 6.7 0.014 0.64 0.12 0.02 0.08 3.06 024 3.31 0.071 0.181 2.17 4.21 2.40 0.83 CB827 CB#26 0.58 0.55 24 �2 6.3 0.014 0.64 0.58 0.37 0.37 3.19 1.19 2.45 0.483 0.490 5.88 3.13 3.12 0.13 CB#26 CBM24 0.45 1.95 150 t 2 7.6 0.014 0.64 0.45 029 0.74 2.85 2.10 4.62 0.454 0.474 5.68 5.88 5.79 0.43 CB#25 CB#24 0.51 0.55 24 12 6.3 0.014 0.64 0.51 0.33 0.33 3.19 1.04 2.45 0.425 0.457 5.48 3.13 3.02 0.13 CB#24 CBIt23 0.43 1.00 146 �8 8.0 0.014 0.64 0.43 0.28 1.34 2.75 3.68 9.75 0.377 0.425 7.65 5.52 5.13 0.47 CB#23 CBN20 0.48 0.55 41 18 8.5 0.014 0.64 0.91 0.31 1.64 2.65 4.36 7.23 0.603 0.558 10.04 4.10 4.27 0.16 CB#22 CBri21 0.62 0.55 34 12 6.3 0.014 0.64 0.62 0.40 0.40 3.19 1.27 2.45 0.516 0.509 6.11 3.13 3.16 0.18 CB821 CBf�20 0.81 0.55 25 18 6.5 0.014 0.64 1.43 0.52 0.92 3.14 2.87 7.23 0.397 0.438 7.88 4.10 3.86 0.11 CB#20 CBM19 0.04 0.55 23 1b 8.6 0.014 0.64 0.04 0.03 2.59 2.62 6.78 7.23 0.937 0.762 13.71 4.10 4.63 0.08 CB#19 C8q17 0.09 0.55 143 24 8.7 0.014 0.64 0.13 0.06 2.64 2.60 6.89 15.57 0.442 0.467 1121 4.96 4.85 0.49 CB#18 CBq17 0.59 1.00 24 72 6.3 0.014 0.64 0.59 0.38 0.38 3.19 1.21 3.31 0.365 0.417 5.00 4.21 3.88 0.10 CB#17 CB#16 0.01 0.55 61 24 92 0.014 0.64 0.01 0.01 3.03 2.52 7.62 15.57 0.489 0.494 11.85 4.96 4.96 0.20 CB#16 CBM15 0.39 0.55 24 24 9.4 0.014 0.64 0.4 025 328 2.48 8.13 15.57 0.522 0.513 12.30 4.96 5.02 0.08 CB#15 CB#6 0.06 0.55 109 24 9.5 0.014 0.64 0.46 0.04 3.32 2.47 8.18 15.57 0.525 0.515 12.35 4.96 5.02 0.36 CB#14 CB#13 0.11 0.55 158 12 6.3 0.01A 0.64 0.11 0.07 0.07 3.19 0.22 2.45 0.092 0.202 2.43 3.13 1.90 1.38 CB#13 CBIf11 0.02 0.55 37 12 7.7 0.014 0.64 0.13 0.01 0.08 2.82 0.23 2.45 0.096 0.207 2.49 3.13 1.94 0.32 CB#12 CB#11 0.14 3.58 57 12 6.3 0.014 0.64 0.14 0.09 0.09 3.19 0.29 626 0.046 0.148 1.77 7.97 4.00 0.24 CBM11 CB#9 0.02 0.55 58 12 S.0 0.014 0.64 O.Q2 0.01 0.19 2.75 0.51 2.45 0.208 0.306 3.67 3.13 2.45 0.39 CB#10 CB#9 0.64 2.47 24 12 8.3 0.014 0.64 0.64 0.41 0.41 3.19 1.31 520 0.252 0.341 4.10 6.62 5.51 0.07 CB#9 CB#7 0.82 0.55 247 t 8 8.4 0.014 0 64 0.82 0.52 7.12 2.66 2.98 7.23 0.413 0.448 8.07 4.10 3.91 7.OS Page 1 16834-Co��veyance.xls CBMB CBa►7 0.41 0.55 25 7 2 6.3 0.014 0.64 0.41 0.26 026 3.19 0.84 2.45 0.342 0.404 4.84 3.13 2.84 0.15 CB#7 CB#6 0.08 0.55 31 18 9.4 0.014 0.64 0.06 0.04 1.71 2.47 423 7.23 0.584 0.548 9.87 4.10 4.24 0.12 CB#6 CB#5 0.08 0.50 29 30 9.8 0.014 0.64 0.08 0.05 5.08 2.41 12.24 26.92 0.454 0.474 14.22 5.49 5.40 0.09 CB#5 C8#3 0.52 0.50 198 30 9.9 0.014 0.64 0.6 0.33 5.41 2.40 72.96 26.92 0.482 0.489 14.68 5.49 5.47 0.60 CB#4 CB#3 0.05 1.00 65 12 6.3 0.014 0.64 0.05 0.03 0.03 3.19 0.10 3.31 0.031 0.122 1.46 4.21 1.88 0.58 CB#3 POND 0.66 1.72 232 30 10.5 0.014 0.64 0.66 0.42 5.86 2.31 13.54 49.93 0.271 0.358 10.73 10.18 8.68 0.45 Page 2 3.2.1 RAT[ONAL METHOD FIGURE 3.2.1.D 100-YEAR 24HOUR ISOPLUViALS 3�—�I __r,____ __ O COUMTY T N COUNTY �� ' Ho� ii� / . 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By cka. rovr. Raviaion Job N�mber $Cole: Q.G' A�y1 18215 72ND AVENUE SOUTH °iaiv°�d �` TMb' 16834 P R` KENT wn sao3z o.ow� „,�_,�,,, �UADRANT HOMES m� " Z �azsj zsi—szzz ,•_So� 14725 SE 36TH ST. SUITE 200 PIPE SIZING AREA MAP sn«c o � (425) 251-8782 FAX cn.�k.a—_ � � _ ^�p�°�°a �°rt'°°' BELLEVUE, WA 98006 FOR s� P5� CIVIL ENCINEERINC, UND PIANNING, N�� COPPERWOOD 1 of � �'iN��N�1NE�' SURVEYING, ENVIRONAIENTAL SERVICES Date BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:16834bwl.bwp Surcharge condition at intermediate junctions Tailwater Elevation:384. feet Discharge Range:12.59 to 13.54 Step of 0.1 [cfs] Overflow Elevation:393.08 feet Weir:NONE Channel Width:2. feet CB#3 => POND PIPE N0. 1: 232 LF - 30"CP @ 1.72� OUTLET: 373.00 INLET: 377.00 INTYP: 5 JUNC NO. 1: OVERFLOW-EL: 386.70 BEND: 66 DEG DIA/WIDTH: 4.5 Q-RATIO: 0.05 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO AWI ****************r************************************,r************************* 12.59 7.32 384.32 * 0.012 1.19 0.79 11.00 11.00 7.19 7.32 1.67 12.69 7.32 384.32 * 0.012 1.20 0.80 11.00 11.00 7.19 7.32 1.68 12.79 7.33 384.33 * 0.012 1.20 0.80 11.00 11.00 7.19 7.33 1.69 12.89 7.33 384.33 * 0.012 1.21 0.80 11.00 11.00 7.19 7.33 1.70 12.99 7.39 3B4.39 * 0.012 1.21 0.81 11.00 11.00 7.20 7.34 1.71 13.09 7.39 384.39 * 0.012 1.22 0.81 11.00 11.00 7.20 7.34 1.71 13.19 7.35 384.35 * 0.012 1.22 0.81 11.00 11.00 7.20 7.35 1.72 13.29 7.35 384.35 * 0.012 1.23 0.81 11.00 11.00 7.21 7.35 1.73 13.39 7.36 369.36 * 0.012 1.23 0.82 11.00 11.00 7.21 7.36 1.79 13.49 7.37 389.37 * 0.012 1.29 0.82 11.00 11.00 7.21 7.37 1.75 13.59 7.37 384.37 * 0.012 1.29 0.82 11.00 11.00 7.22 7.37 1.75 C B#5 => C B#3 PIPE N0. 2: 198 LF - 30"CP Q 0.50� OUTLET: 377.00 INLET: 377.99 INTYP: 5 JUNC N0. 2: OVERFLOW-EL: 387.31 BEND: 0 DEG DIA/WIDTH: 4.5 Q-RATZO: 0.06 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI I ,t*,t*,t**,t**t,t+t,t*,kr***,t,t,t****,t*,t*,t***,t**,t�,t**,t*,t,t,t,t,t,t,t,t**+r,t,tt****,t*rt�,t*,t*,t******,t 11.99 6.59 384.53 * 0.012 1.16 1.07 7.32 7.32 6.48 6.54 1.58 12.09 6.59 384.53 * 0.012 1.17 1.08 7.32 7.32 6.48 6.54 1.59 12.13 6.55 384.59 * 0.012 1.17 1.08 7.33 7.33 6.49 6.55 1.60 12.23 6.56 384.55 * 0.012 1.18 1.09 7.33 7.33 6.99 6.56 1.b0 12.32 6.57 384.56 * 0.012 1.18 1.09 7.34 7.34 6.50 6.57 1.61 12.92 6.58 384.57 * 0.012 1.19 1.10 7.34 7.34 6.51 6.58 1.62 12.51 6.58 384.57 * 0.012 1.19 1.10 7.35 7.35 6.52 6.58 1.62 12.61 6.59 384.58 * 0.012 1.20 1.11 7.35 7.35 6.52 6.59 1.63 12.70 6.60 3B4.59 * 0.012 1.20 1.11 7.36 7.36 6.53 6.60 1.64 12.80 6.61 389 .60 * 0.012 1.21 1.12 7.37 7.37 6.54 6.61 1.69 12.90 6.62 389 .61 * 0.012 1.21 1. 12 7.37 7.37 6.55 6.62 1 .55 ', CB#6 => CB#5 PIPE N0. 3: 29 LF - 30"CP @ 0.52� OUTLET: 377.99 ZNLET: 378.19 INTYP: 5 i JUNC NO. 3: OVERFLOW-EL: 386.92 BEND: 90 DEG DIA/WIDTH: 4.5 Q-RATIO: 0.50 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI *****************************************�***#***�***************************�* 11.27 6.60 384.79 * 0.012 1.13 1.03 6.54 6.59 6.92 6.60 1.66 11.36 6.59 369.73 * Q.012 1.13 1.03 6.54 6.59 6.41 6.59 1.67 11.45 6.61 364.75 * 0.012 1.14 1.04 6.55 6.55 6.42 6.61 1.68 11.54 6.62 384.76 * 0.012 1.14 1.04 6.56 6.56 6.93 6.62 1.66 11.63 6.63 384.77 * 0.012 1.15 1.05 6.57 6.57 6.99 6.63 1.69 11.72 6.64 389.78 * 0.012 1.15 1.05 6.58 6.58 6.45 6.69 1.70 11.81 6.65 364.79 * 0.012 1.16 1.06 6.58 6.58 6.95 6.65 1.71 11.90 6.67 389.81 * 0.012 1.16 1.06 6.59 6.59 6.46 6.67 1.72 11.99 6.68 384.82 * 0.012 1.17 1.07 6.60 6.60 6.47 6.68 1.73 12.08 6.69 389.83 * 0.012 1.17 1.07 6.61 6.61 6.48 6.69 1.74 12.17 6.70 384.89 * 0.012 1.18 1.07 6.62 6.62 6.99 6.70 1.74 CB#15 => CB#6 PIPE NO. 4: 109 LF - 29"CP @ 0.55$ OUTLET: 378.64 INLET: 379.24 INTYP: 5 JUNC NO. 4: OVERFLOW-EL: 387.97 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATZO: 0.01 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **************************************+r*****��*********�c*****:**********.***,�** 7.51 5.77 385.01 * 0.012 0.98 0.90 6.10 6.10 5.61 5.77 1.93 7.57 5.76 395.00 * 0.012 0.98 0.90 6.09 6.09 5.60 5.76 1.44 7.63 5.78 385.02 * 0.012 0.99 0.91 6.11 6.11 5.61 5.78 1 7.69 5.79 385.03 * 0.012 0.99 0.91 6.12 6.12 5.63 5.79 1 . 7.75 5.81 385.05 * 0.012 1.00 0.92 6.13 6.13 5.69 5.91 1 7.81 5.83 385.07 * 0.012 1.00 0.92 6.19 6.19 5.65 5.83 1. 7.67 5.89 385.08 * 0.012 1.00 0.92 6.15 6.15 5.67 5.84 1 . - 7.93 5.86 365.10 * 0.012 1.01 0.93 6.17 6.17 5.69 5.86 1. � 7.99 5.88 385.12 * 0.012 1.01 0.93 6.18 6.18 5.69 5.88 1. _;+ 6.05 5.89 385.13 * 0.012 1 .02 0. 94 6. 19 6.19 5.71 5.89 1. Si'� 8.11 5.91 �25. 15 � , .���1= -. ;2 � . 9= _ .ZO �0. �0 5. ?2 5. 9_ _ .51 CB#16 => CB#1:-; PIPE N0. 5: 29 �F - 24"CF � U. �90 CUILET: 37y.24 I:dLET: 379.37 INIYP: � JUNC N0. 5: OVERFLOW-EL: 387.47 BEND: 45 DEG DIA/WIDTH: 9.0 Q-RATIO: 0.07 Q(CFS) HW(FTj HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **�*�******************,r*****:**********#********************************#***a* 7.99 5.76 385.13 * 0.012 0.97 0.90 5.77 5.77 5.67 5.76 1.35 7.50 5.75 385.12 * 0.012 0.98 0.90 5.76 5.76 5.66 5.75 1.36 7.56 5.76 385.13 * 0.012 0.98 0.91 5.78 5.78 5.67 5.76 1.37 7.61 5.78 385.15 * 0.012 0.99 0.91 5.79 5.79 5.69 5.78 1.37 7.67 5.80 385.17 * 0.012 0.99 0.92 5.81 5.81 5.70 5.80 1.38 7.73 5.82 385.19 * 0.012 0.99 0.92 5.83 5.83 5.72 5.82 1.39 7.79 5.84 385.21 * 0.012 1.00 0.92 5.84 5.84 5.79 5.89 1.39 7.85 5.85 385.22 * 0.012 1.00 0.93 5.86 5.86 5.76 5.85 1.90 7.91 5.87 385.24 * 0.012 1.01 0.93 5.88 5.88 5.77 5.87 1.90 7.97 5.89 385.26 * 0.012 1.01 0.99 5.89 5.89 5.79 5.89 1.91 8.03 5.91 385.28 * 0.012 1.01 0. 99 5. 91 5. 91 �.81 5. 91 1 .92 CB#17 => CB#16 PIPE NO. 6: 61 LF - 29"CP @ 0.56� OUTLET: 379.37 INLET: 379.71 INTYP: 5 JUNC NO. 6: OVERFLOW-EL: 387.75 BEND: 45 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.11 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO IiWI ****************************************************************r************** 6.95 5.55 385.26 * 0.012 0.99 0.86 5.76 5.76 5.97 5.55 1.31 7.01 5.54 385.25 * 0.012 0.99 0.86 5.75 5.75 5.96 5.54 1.31 7.06 5.56 385.27 * 0.012 0.95 0.87 5.76 5.76 5.97 5.56 1.32 7.12 5.58 385.29 * 0.012 0.95 0.87 5.78 5.78 5.49 5.58 1.32 7.17 5.60 385.31 * 0.012 0.96 0.87 5.80 5.80 5.51 5.60 1.33 7.23 5.62 385.33 * 0.012 0.96 0.88 5.B2 5.82 5.53 5.62 1.39 7.28 5.69 385.35 * 0.012 0.96 0.88 5.89 5.89 5.55 5.69 1.39 7.39 5.66 385.37 * 0.012 0.97 0.89 5.85 5.85 5.57 5.66 1.35 7.39 5.68 385.39 * 0.012 0.97 0.89 5.87 5.87 5.59 5.68 1.35 7.45 5.70 385.91 * 0.012 0.98 0.89 5.89 5.89 5.61 5.70 1.36 7.50 5.72 385.93 * 0.012 0.98 0.90 5.91 5.91 5.63 5.72 1.37 CB#19 => CB#17 PIPE N0. 7: 143 LF - 24"CP @ 0.55$ OUTLET: 379.71 INLET: 380.50 INTYP: 5 JUNC N0. 7: OVERFLOW-EL: 386.91 BEND: 15 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.02 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI �,r�**,r********:***:**•r*************,r*******,r*«*****************•**r*******,r*** 6.26 9.86 385.36 * 0.012 0.89 0.81 5.55 5.55 9.86 9.78 1.09 6.31 4.89 385.39 * 0.012 0.89 0.82 5.59 5.54 4.84 4.77 1.09 6.36 4.86 385.36 * 0.012 0.90 0.82 5.56 5.56 4.86 4.79 1.09 6.41 9.89 385.39 * 0.012 0.90 0.82 5.58 5.58 4.89 9.81 1.10 6.46 9.91 385.41 * 0.012 0.91 0.83 5.60 5.60 4.91 9.83 1.10 6.51 4.93 385.43 * 0.012 0.91 0.83 5.62 5.62 4.93 4.85 1.10 6.56 9 .95 385.45 * 0.012 0.91 0.83 5.69 5.64 9.95 4.87 1.11 6.61 9.97 385.47 * 0.012 0.92 0.84 5.66 5.66 9.97 9.89 1.11 6.66 5.00 385.50 * 0.012 0.92 0.84 5.68 5.68 5.00 9.91 1.11 6.71 5.02 385.52 * 0.012 0.92 0.85 5.70 5.70 5.02 9.93 1.12 6.76 5.09 385.59 * 0.012 0.93 0.85 5.72 5.72 5.09 4.95 1.12 CB#20 => CB#19 PIPE NO. S: 23 LF - 18"CP @ 0.57$ OIITLET: 381.00 INLET: 381.13 INTYP: 5 JUNC NO. 8: OVERFLOW-EL: 386.32 BEND: 45 DEG DIA/WIDTH: 9.0 Q-RATIO: 0.55 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ��a��+r**,t**,t*,t,t****,t,t,t****,t,t*,t,k*****,t*,t,r**,t**,t**+r,t,t*,t*,t,t**,t,t,t*,t**,tt,t*,t***,t***,t,t 6.14 4.56 385.69 * 0.012 0.96 0.95 9.36 4.36 9.30 4.56 1.47 6.19 4.55 385.68 * 0.012 0.97 0.95 9.39 4.39 9.28 4.55 1.47 6.24 4.57 385.70 * 0.012 0.97 0.96 9.36 4.36 4.30 4.57 1.98 6.29 4.60 385.73 * 0.012 0.97 0.96 4.39 4.39 9.33 4.60 1.99 6.33 4.63 385.76 * 0.012 0.98 0.97 4.41 9.41 4.35 4.63 1.50 6.38 4.66 385.79 * 0.012 0.98 0.97 4.93 9.93 4.37 4.66 1.51 0.43 4.68 385.81 * 0.012 0.99 0.98 4.45 9.95 4.40 4.68 1.51 6.98 9.71 385.89 * 0.012 0.99 0.98 4.97 9.97 4.42 9.71 1.52 6.53 4.74 385.87 * 0.012 0.99 0.99 4.50 9.50 4.44 4.74 1.53 6.58 9.77 385.90 * 0.012 1.00 0.99 4.52 9.52 9.47 9.77 1.59 6.63 9.79 385.92 * 0.012 1.00 1.00 4.54 9.54 9.99 9.79 1.55 CB#23 => CB#20 PZPE NO. 9: 41 LF - 18"CP @ 0.56$ OUTLET: 381.13 INLET: 381.36 INTYP: 5 JUNC NO. 9: OVERFLOW-EL: 386.63 BEND: 30 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.19 Q(CFS) HW(FTj HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ********,r****************,r*,r,+**,r*:******�************r******�**,r**********s**** 3.96 4.97 385.83 * 0.012 0.77 0.72 9.56 4.56 4.39 9.47 1.07 3.99 4.45 385.81 * 0.412 0.77 0.73 4.55 4.55 4.37 4.45 1.08 4.02 4.48 385.89 * 0.012 0.77 0.73 4.57 4.57 4.90 4.48 1.08 4.06 4.51 385.87 * 0.012 0.78 0.73 4.60 4.60 4.92 4.51 1.09 4.09 4.54 385.90 * 0.012 0.78 0.74 4.63 4.63 4.45 4.54 1.09 4.12 9.57 385.93 * 0.012 0.78 0.79 4.66 9.66 4.48 9.57 1.10 4.15 9.60 385.96 * 0.012 0.79 0.79 9.68 9.68 4.51 9.60 1.10 4.16 9.63 385.99 * 0.012 0.79 0.75 4.71 9.71 9.59 9.63 1.11 4.21 4.66 386.02 * 0.012 0.79 0.75 9.74 9.74 4.56 9.66 1.11 4.24 9.69 386.05 * 0.012 0.79 0.75 4.77 9.77 9.59 4.69 1.12 4.28 4.72 386.08 * 0.012 0.80 0.76 9.79 9.79 9.62 9.72 1.12 C B#24 => C B#23 PIPE N0.10: 146 LF - 18"CP @ *****$ OUTLET: 381.36 INLET: 182.61 INTYP: 5 JUNC NO.10: OVERFLOW-EL: 388.09 BEND: 0 DEG DIA/WIDTH: 3.0 Q-RATIO: 0.76 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **,r********************,r*******,r**,r*********************,r***�*****,r■,r***.***,r** 3.33 203.23 386.04 * 0.012 0.70 0.00 4.47 9.97203.15 ***** 2.02 3.35 203.21 386.02 * 0.012 0.70 0.00 4.95 4.95203.13 ***** 2.02 3.38 203.24 386.05 * 0.012 0.71 0.00 4.48 9.98203.16 ***** 2.03 3.91 203.28 386.09 * 0.012 0.71 0.00 9.51 9.51203.19 ***** 2.03 3.43 203.31 386.12 * 0.012 0.71 0.00 9.59 9.54203.22 ***** 2.09 3.96 203.34 386.15 * 0.012 0.71 0.00 9.57 4.57203.25 ***** 2.09 3.99 203.37 386.18 * 0.012 0.72 0.00 9.60 4.60203.28 ***** 2.05 3.51 203.91 386.22 * 0.012 0.72 0.00 9.63 4.63203.32 ***** 2.05 3.59 203.44 386.25 * 0.012 0.72 0.00 9.66 4.66203.35 ***** 2.06 3.57 203.48 386.29 * 0.012 0.73 0.00 9.69 9.69203.38 ***** 2.06 3.59 203.51 386.32 * 0.012 0.73 0.00 4.72 9.72203.41 ***** 2.07 CB#26 => CB#24 PIPE NO.11: 150 LF - 12"CP @ 1.95$ OUTLET: 383.31 INLET: 386.23 INTYP: 5 JUNC NO.11: OVERFLOW-EL: 389.50 BEND: � DEG DIA/WIDTH: 3.0 Q-RATIO: 7.71 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI �***********:*r*****,c************#***********�*****+r**************,r,r*********** 1.89 0.88 387.11 * 0.012 0.59 0.91 2.73 2.73 0.59 ***** 0.88 1.91 0.88 387.11 * 0.012 0.59 0.92 2.71 2.71 0.59 ***** 0.88 1.92 0.89 387.12 * 0.012 0.60 0.92 2.74 2.74 0.60 ***** 0.69 1.94 0.89 387.12 * 0.012 0.60 0.42 2.78 2.78 0.60 ***** 0.89 1.95 0.90 387.13 * 0.012 0.60 0.92 2.81 2.81 0.60 ***** 0.90 1.97 0.90 387.13 * 0.012 0.60 0.92 2.84 2.89 0.60 ***** 0.90 1.98 0.91 387.19 * 0.012 0.61 0.42 2.87 2.87 0.61 ***** 0.91 2.00 0.91 387.19 * 0.012 0.61 0.43 2.91 2.91 0.61 ***** 0.91 2.01 0.91 387.19 * 0.012 0.61 0.43 2.99 2.99 0.61 ***** 0.91 2.03 Q.92 387.15 * 0.012 0.61 0.93 2.98 2.98 0.61 ***** 0.92 2.09 0.92 387.15 * 0.012 0.62 0.43 3.01 3.01 0.62 ***** 0.92 CB#28 => CB#26 PIPE N0.12: 119 LF - 12"CP @ 1.00$ OUTLET: 386.23 INLET: 387.92 INTYP: 5 . JUNC N0.12: OVERFLOW-EL: 390.89 BEND: 95 DEG DIA/WIDTH: 3.0 Q-RATZO: 0.33 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ********************************r********************************�***�********* 0.22 0.25 387.67 * 0.012 0.20 0.17 0.88 0.88 0.20 ***** 0.25 0.22 0.26 387.68 * 0.012 0.20 0.17 0.88 0.88 0.20 ***** 0.26 0.22 0.26 387.68 * 0.012 0.20 0.17 0.89 0.89 0.20 ***** 0.26 - 0.22 0.26 387.68 * 0.012 0.20 0.17 0.89 0.89 0.20 ***** 0.26 0.22 0.26 387.68 * 0.012 0.20 0.17 0.90 0.90 0.20 ***** 0.26 0.23 0.26 387.68 * 0.012 0.20 0.17 0.90 0.90 0.20 ***** 0.26 0.23 0.26 387.68 * 0.012 0.20 0.17 0.91 0.91 0.20 ***** 0.26 0.23 0.26 387.68 * 0.012 0.20 0.17 0.91 0.91 0.20 ***** 0.26 0.23 0.26 387.68 * 0.012 0.20 0.17 0.91 0.91 0.20 ****x 0.26 0.23 0.26 387.68 * 0.012 0.20 0.17 0.92 0.92 0.20 ***** 0.26 0.23 0.26 387.68 * 0.012 0.20 0.17 0.92 0.92 0.20 ***** 0.26 Ci8$t29 => IiO�G� PIPE N0.13: 76 LF - 12"CP 8 2.18$ OUTLET: 387.92 INLET: 389.08 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI *+*�*************************************************************************** 0.16 0.21 389.29 * 0.012 0.17 0.12 0.25 0.25 0.17 ***** 0.21 0.16 0.21 389.29 * 0.012 0.17 0.12 0.26 0.26 0.17 ***** 0.21 0.17 0.21 389.29 * 0.012 0.17 0.12 0.26 0.26 0.17 ***** 0.21 0.17 0.21 389.29 * 0.012 0.17 0.12 0.26 0.26 0.17 ***** 0.21 0.17 0.21 389.29 * 0.012 0.17 0.12 0.26 0.26 0.17 ***** 0.21 0.17 0.21 389.29 * 0.012 0.17 0.12 0.26 0.26 0.17 ***** 0.21 0.17 0.22 389.30 * 0.012 0.17 0.12 0.26 0.26 0.17 ***** 0.22 0.17 0.22 389.30 * 0.012 0.17 0.12 0.26 0.26 0.17 ***** 0.22 0.17 0.22 389.30 * 0.012 0.18 0.12 0.26 0.26 0.18 ***** 0.22 0.17 0.22 389.30 * 0.012 0.18 0.13 0.26 0.26 0.18 ***** p.22 0.18 0.22 389.30 * 0.012 0.18 0.13 0.26 0.26 0.18 ***** 0.22 BACKWATER COMPUTER PROGRI�M FOR PIPES Pipe data from file:16839BW2.bwp Surcharge condition at intermediate junctions Tailwater Elevation:384.84 feet Discharge Range:3.23 to 4.23 Step of 0.1 [cfsj Overflow Elevation:385.63 feet Weir:NONE Channel Width:2. feet CB$�7 => CiB#6 PIPE NO. 1: 31 LF - 18"CP @ 0.55$ OUTLET: 379.14 INLET: 379.31 INTYP: 5 JUNC NO. 1: OVERFLOW-EL: 386.32 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.92 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **«***********,r************,r+r****************s***,r*+r*,r*****,r*,r+r,e***,�*********** 3.23 5.62 389.93 * 0.012 0.69 0.65 5.70 5.70 5.56 5.62 0.96 3.33 5.62 389.93 * 0.012 0.70 0.66 5.70 5.70 5.56 5.62 0.98 3.43 5.63 369.99 * 0.012 0.71 0.67 5.70 5.70 5.56 5.63 0.99 3.53 5.63 364.99 * 0.012 0.72 0.68 5.70 5.70 5.56 5.63 1.01 3.63 5.69 389.95 * 0.012 0.73 0.69 5.70 5.70 5.56 5.69 1.03 3.73 5.64 389.95 * 0.012 0.74 0.70 5.70 5.70 5.56 5.69 1.09 3.83 5.65 389.96 * 0.012 0.75 0.71 5.70 5.70 5.57 5.65 1.06 3.93 5.66 384.97 * 0.012 0.76 0.73 5.70 5.70 5.57 5.66 1.08 � 9.Q3 5.66 384.97 * 0.012 0.77 0.79 5.70 5.70 5.57 5.66 1.09 9.13 5.67 384.98 * 0.012 0.78 �.75 5.70 5.70 5.57 5.67 1.11 4.23 5.68 384.99 * 0.012 0.79 0.76 5.70 5.70 5.57 5.68 1.12 4.23 5.68 384.99 * 0.012 0.79 0.76 5.70 5.70 5.57 5.68 1.12 Ci8$�9 => li6$�7 PIPE NO. 2: 247 LF - 18"CP @ 0.55$ OUTLET: 379.31 INLET: 380.67 INTYP: 5 JUNC NO. 2: OVERFLOW-EL: 385.77 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 4.84 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ��,r*.,r*********:***:,r,r*************,r******+r,r*************�************+r**s***** 2.27 4.40 385.07 * 0.012 0.58 0.54 5.62 5.62 9.36 9.90 0.79 2.35 4.41 385.08 * 0.012 0.58 0.55 5.62 5.62 9.37 9.91 0.81 2.42 4.42 385.09 * 0.012 0.59 0.55 5.63 5.63 4.38 9.92 0.82 2.49 9.49 385.11 * 0.012 0.60 0.56 5.63 5.63 4.39 9.99 0.84 2.56 9.45 385.12 * 0.012 0.61 0.57 5.69 5.69 9.90 9.95 0.85 2.63 4.47 385.14 * 0.012 0.62 0.58 5.69 5.69 4.92 4.47 0.86 .� 2.70 4.48 385.15 * 0.012 0.63 0.59 5.65 5.65 9.93 9.98 0.88 2.77 4.50 385.17 * 0.012 0.69 0.60 5.66 5.66 9.99 9.50 0.89 2.84 4.52 385.19 * 0.012 0.69 0.60 5.66 5.66 9.96 4.52 0.90 2.91 4.53 385.20 * 0.012 0.65 O.bl 5.67 5.67 9.97 9.53 0.92 2.98 4.55 385.22 * 0.012 0.66 0.62 5.68 5.68 9.99 9.55 0.93 2.98 4.55 385.22 * 0.012 0.66 0.62 5.68 5.68 9.99 9.55 0.93 CB#11 => CB#9 PIPE N0. 3: 58 LF - 12"CP @ 0.55$ OUTLET: 381.17 INLET: 381.99 INTYP: 5 JUNC N0. 3: OVERFLOW-EL: 386.27 BEND: 95 DEG DIA/WIDTH: 3.0 Q-RATIO: 1.22 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ******#********************************************�***********r*************** 0.39 3.60 385.09 * 0.012 0.26 0.25 3.90 3.90 3.59 3.60 0.35 0.40 3.60 385.09 * 0.012 0.27 0.26 3.91 3.91 3.59 3.60 0.36 0.41 3.61 385.10 * 0.012 0.27 0.26 3.92 3.92 3.61 3.61 0.36 0.43 3.63 385.12 * 0.012 0.27 0.27 3.99 3.99 3.62 3.63 0.37 0.94 3.65 385.14 * 0.012 0.28 0.27 3.95 3.95 3.64 3.65 0.37 0.95 3.66 385.15 * a.012 0.28 0.27 3.97 3.97 3.66 3.66 0.38 0.96 3.68 385.17 * 0.012 0.29 0.28 3.98 3.98 3.67 3.68 0.38 0.97 3.70 385.19 * 0.012 0.29 0.26 9.00 9.00 3.69 3.70 0.39 0.99 3.72 385.21 * 0.012 0.29 0.28 9.02 9.02 3.71 3.72 0.39 0.50 3.73 385.22 * 0.012 0.30 0.29 4.03 4.03 3.72 3.73 0.90 0.51 3.75 385.29 * 0.012 0.30 0.29 4.05 4.05 3.79 3.75 0.90 � 0.51 3.75 385.24 * 0.012 0.30 0.29 4.05 4.05 3.79 3.75 0.90 CB#13 => CB#11 PIPE NO. 9: 37 LF - 12"CP @ U.54$ OUTLET: 381.99 INLET: 381.69 INTYP: 5 JUNC NO. 9: OVERFLOW-EL: 386.64 BEND: 45 DEG DIA/WIDTH: 3.0 Q-RATIO: 0.05 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI �****************************************************#************+�*********** 0.18 3.90 385.09 * 0.012 0.18 0.17 3.60 3.60 3.90 3.90 0.23 0.18 3.90 385.09 * 0.012 0.18 0.18 3.60 3.60 3.90 3.40 0.23 0.19 3.92 385.11 * 0.012 0.18 0.18 3.61 3.61 3.92 3.42 0.29 0.19 3.93 385.12 * 0.012 0.18 0.18 3.63 3.63 3.93 3.43 0.29 0.20 3.45 385.14 * 0.012 0.19 0.18 3.65 3.65 3.95 3.45 0.29 0.20 3.47 385.16 * 0.012 0.19 �.19 3.66 3.66 3.96 3.97 0.25 0.21 3.48 385.17 * 0.012 0.19 0.19 3.68 3.68 3.98 3.48 0.25 0.21 3.50 385.19 * 0.012 0.19 0.19 3.70 3.70 3.50 3.50 0.25 0.22 3.52 385.21 * 0.012 0.20 0.19 3.72 3.72 3.52 3.52 0.26 0.22 3.59 385.23 * 0.012 0.20 0.20 3.73 3.73 3.59 3.54 0.26 0.23 3.56 385.25 * 0.012 0.20 0.20 3.75 3.75 3.55 3.56 0.26 0.23 3.56 385.25 * 0.012 0.20 0.20 3.75 3.75 3.55 3.56 0.26 CB#14 => CB#13 PIPE NO. 5: 158 LF - 12"CP @ 0.55$ OUTLET: 381.69 INLET: 382.56 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **,r***,r*******,t,t+t****:****a**,►*,t*****,r,r,t*rr*,t*****,t**,t*,t*******,t**,r,t,t,t***:tt***** 0.17 2.54 385.10 * 0.012 0.17 0.17 3.90 3.40 2.54 2.54 0.22 0.17 2.54 385.10 * 0.012 0.17 0.17 3.90 3.40 2.53 2.54 0.23 0.18 2.55 385.11 * 0.012 0.18 0.17 3.92 3.42 2.55 2.55 0.23 0.18 2.57 385.13 * 0.012 0.18 0.18 3.93 3.93 2.57 2.57 0.23 0.19 2.58 385.19 * 0.012 0.18 0.18 3.95 3.95 2.58 2.58 0.24 0.19 2.60 385.16 * 0.012 0.19 0.18 3.97 3.97 2.60 2.60 0.24 0.20 2.62 385.18 * 0.012 0.19 0.18 3.98 3.98 2.62 2.62 0.24 0.20 2.64 385.20 * 0.012 0.19 0.19 3.50 3.50 2.63 2.64 0.25 0.21 2.65 385.21 * 0.012 0.19 0.19 3.52 3.52 2.65 2.65 0.25 0.21 2.67 385.23 * 0.012 0.19 0.19 3.54 3.54 2.67 2.67 0.25 ~ 0.22 2.69 385.25 * 0.012 0.20 0.19 3.56 3.56 2.69 2.69 0.26 0.22 2.69 385.25 * 0.012 0.20 0.19 3.56 3.56 2.69 2.69 0.26 .�� BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:16839BW3.bwp Surcharge condition at intermediate junctions ^ailwater Elevation:385.93 feet Discharge Range:1.87 to 2.87 Step of 0.1 [cfs] Overflow Elevation:387.2 feet Weir:NONE Channel Width:2. feet CB#2� _> �iB#2� PIPE NO. 1: 25 LF - 18"CP @ 0.56$ OUTLET: 382.88 INLET: 383.02 INTYP: 5 JUNC NO. 1: OVERFLOW-EL: 386.32 BEND: 90 DEG DIA/WIDTH: 3.0 Q-RATIO: 1.26 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ****�************************+r***�**�*******r**********************,�*********** 1.87 2.96 385.98 * 0.012 0.52 0.48 3.05 3.05 2.92 2.96 0.73 1.97 2.96 385.98 * 0.012 0.53 0.50 3.05 3.05 2.92 2.96 0.75 2.07 2.97 385.99 * 0.012 0.55 0.51 3.05 3.05 2.92 2.97 0.77 2.17 2.98 386.00 * 0.012 0.56 0.52 3.05 3.05 2.92 2.98 0.80 2.27 2.98 386.00 * 0.012 0.57 0.53 3.05 3.05 2.92 2.98 0.82 2.37 2.99 386.01 * 0.012 0.59 0.55 3.05 3.05 2.92 2.99 0.89 2.97 3.00 386.02 * 0.012 0.60 0.56 3.05 3.05 2.92 3.00 0.86 2.57 3.00 386.02 * 0.012 D.61 0.57 3.05 3.05 2.92 3.00 0.88 2.67 3.01 386.03 * 0.012 0.62 0.58 3.05 3.05 2.92 3.01 0.90 2.77 3.02 386.09 * 0.012 0.69 0.59 3.05 3.05 2.92 3.02 0.93 2.87 3.03 386.05 * 0.012 0.65 0.61 3.05 3.05 2.93 3.03 0.95 2.87 3.03 366.05 * 0.012 0.65 0.61 3.05 3.05 2.93 3.03 0.95 CB#22 => CB#21 PIPE NO. 2: 39 LF - 12"CP @ 0.56$ OUTLET: 383.52 INLET: 383.71 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI �,r��******x********,c**************,r********,r************,r********************** 0.83 2.32 386.03 * 0.012 0.39 0.37 2.46 2.96 2.29 2.32 0.53 0.87 2.32 386.03 * 0.012 0.90 0.38 2.46 2.96 2.29 2.32 0.55 0.92 2.33 386.09 * 0.012 0.91 0.39 2.47 2.97 2.30 2.33 0.56 � 0.96 2.39 386.05 * 0.012 0.42 0.40 2.48 2.98 2.31 2.34 0.58 I 1.00 2.35 386.06 * 0.012 0.43 0.91 2.48 2.96 2.32 2.35 0.59 � 1.05 2.37 386.08 * 0.012 0.44 0.92 2.49 2.99 2.32 2.37 0.61 1.09 2.38 386.09 * 0.012 0.49 0.43 2.50 2.50 2.33 2.38 0.62 1.19 2.39 386.10 * 0.012 0.45 0.44 2.50 2.50 2.34 2.39 0.69 1.18 2.40 386.11 * 0.012 0.46 0.45 2.51 2.51 2.35 2.90 0.65 1.23 2.92 386.13 * 0.012 0.47 0.46 2.52 2.52 2.36 2.92 0.67 1.27 2.43 386.14 * 0.012 0.98 0.47 2.53 2.53 2.37 2.43 0.68 1.27 2.93 386.'_9 * 0.012 0.98 0.97 2.53 2.53 2.37 2. 93 0.68 6.0 SPECIAL REPORTS AND STUDIES I The following special reports have been prepared for this project and are included in this section: � 6.1 Geotechnical Report by TeRa Associates, Inc., dated February 10, 2015 6.2 Wetland Report by Soundview Consultants dated July 2014 6.3 Buffer Averaging and Enhancement Plan by Soundview Consultants dated April 24, 2015 16834.015.doc 6. 1 Geotechnical Report prepared by Terra Associates, I nc. dated February 10, 2015 ,I � GEOTECHNICAL REPORT � � � , ; � . � � Copperwood � SE 136th Street and 143rd Avenue SE � Renton, Washington � , ; j Project No. T-6995 . . . �. a�+�•--•� _.n. ., � ..�,. - , _ - --_ : A r . ' " . _. . .' . ._ - � .. .. . •-.'', 'S' . '. < Z �� - ; - - �� Terra Associates, Inc. , ,� . . ._ _ . .. � � . . _ . . - . . Prepared for: Quadrant Homes Bellevue, Washington , February 10, 2014 � Revised February 10, 2015 � , . , . . � . � � � � . . . . . . . � ✓�; ��-�`�" �=ti TERRA ASSOCIATES, I nc. � r-� . � ;�`��` Consultants in Geotechnical Engineering, Geology and Environmental Earth Sciences February 10,2014 Revised February 10,2015 Project No.T-6995 Ms.Bazbara Rodgers Quadrant Homes 14725 SE 36th Street, Suite 200 Bellevue,Washington 98006 Subject: Geotechnical Report Copperwood SE 136th Street and 143rd Avenue SE Renton,Washington Dear Ms.Rodgers: . As requested, we have conducted a geotechnical engineering study for the subject project. The attached report presents our findings and recommendations for the geotechnical aspects of project design and construction. Soil conditions we observed in the test pits generally consisted of 6 to 12 inches of organic topsoil overlying 2 to 5 feet of inedium dense silty sand with gravel(weathered till)overlying dense to very dense silty sand with gravel (unweathered glacial till) to the termination of the test pits. A thicker organic topsoil layer (18 inches) was observed overlying these native till soils at Test Pit TP-9. We also observed about 18 inches of silty sand fill material below 6 inches of gravelly topsoil at Test Pit TP-7. We would expect other areas of shallow surface fills associated with the e�tisting developed parcels will be present. Shallow perched groundwater was observed at a depth of about 4 feet at 3 of the 11 test pits excavated. In our opinion, soil conditions observed at the site will be suitable for support of the proposed development provided the recommendations presented in this report are incorporated into project design and construction. We trust the infomiation presented in this report is su�icient for yow current needs. If you have any questions or require additional inforn�ation,please call. Sincerely yours, TERRA ASSOCIATES,INC. Car e A Pr a � � �� � J. r, Z I � _��'— _ � • Pres' �FC I��C ti�� CS�' �s���1 Ai.�C'� 12525 bVillows Road NE, Suite 101, Kirkland,Washington 98034 Phone (425) 821-7777 • Fax (�">>) t321--�33� TABLE OF CONTENTS Page No. 1.0 Project Description.......................................................................................................... 1 2.0 Scope of Work................................................................................................................. 1 3.0 Site Conditions................................................................................................................2 3.1 Surface................................................................................................................Z 3.2 Subsurface..........................................................................................................2 3.3 Groundwater.......................................................................................................3 4.0 Geologic Hazards............................................................................................................3 4.1 Seismic Considerations......................................................................................3 4.2 Erosion Hazard Areas.........................................................................................4 4.3 Landslide Hazard Areas.....................................................................................4 5.0 Discussion and Reconunendations..................................................................................4 5.1 General...............................................................................................................4 5.2 Site Preparation and Grading .............................................................................5 5.3 Excavation..........................................................................................................6 - 5.4 Slopes and Embankments...................................................................................6 5.5 Foundation Support............................................................................................7 5.6 Floor Slab-on-Grade........................................................................................... 7 5.7 Stormwater Detention Pond ............................................................................... 7 5.8 Rockery.............................................................................................................. 8 5.9 Drainage............................................................................................................. 8 5.10 Utilities...............................................................................................................9 5.11 Pavement............................................................................................................9 6.0 Additional Services....................................................................................................... 10 7.0 Limitations..................................................................................................................... 10 Fi ures VicinityMap.........................................................................................................................Figure 1 TopographicVicinity Map................................................................................................... Figure 2 ExplorationLocation Plan.................................................................................................... Figure 3 CutRockery Detail...............................................................................................................Figure 4 Aqpendix Field Exploration and Laboratory Testing........................................................................Appendix A Geotechnical Report Copperwood SE 136th Street and 143rd Avenue SE Renton, Washington 1.0 PROJECT DESCRIPTION , The project consists of developing the approximately 12.7-acre site with 47 residential building lots, access roadways, a stormwater detention pond, a rockery,and utilities. Based on the"Overall Grading Plan"prepared by Barghausen Consulting Engineers dated October 8, 2014 cuts and fills required to establish design lot and roadway elevations will be on the order of one to ten feet. There is an approximately four-foot tall cut rockery planned along the west side of Lots b and 7. Stormwater�vill be collected and routed to a detention pond located in the southeast corner of the site. The pond ! will be formed mainly by excavating below current site grade with construction of a small fill containment berm along the east perimeter. The excavation required to achieve the floor elevations of 372 and 370 will extend 14 to 20 feet below current site grades. The fill depth required to achieve the berm crest elevation of 386 will range from 2 to 4 feet. The pond berm width is six feet, with exterior and interior pond slopes graded at 2:1 and 3:1, respectively. We expect that the residentiat structures constructed on the lots will be two- to three-story, wood-framed buildings with their main floor levels framed over a crawl space. Attached garage floors will be constructed at b ade. Structural loading should be relatively light; with bearing walls caring loads of 2 to 3 kips per foot and isolated columns caring maximum loads of 30 to 40 kips. The recommendations in the following sections of this report are based on our understanding of the preceding design features. We should review final design drawings as they become available to verify that our recommendations have been properly interpreted and to supplement them, if required. 2.0 SCOPE OF WORK Our scope of work was completed in accordance with our authorized proposal dated January 9, 2014. Accordingly on January 17, 2014, we observed soil conditions at 11 test pits excavated between 6 and 10 feet below existing site grades. Using the information obtained from the subsurface exploration, we performed analyses to develop geotechnical recommendations for project design and construction. Specifically, this report addresses the following: • Soil and groundwater conditions • Seismic design parameters per 2009 International Building Code(IBC) • Geologic Hazards per cunent City of Renton Municipal Code • Site preparation and grading � Excavation February 10, 2014 Revised Februa�y 10, 2015 Project No. T-699� • Foundations • Floor slabs at grade • Stormwater detention ponds • Rockery • Drainage • Utilities • Pavement It should be noted that recommendations outlined in this report regarding drainage are associated with soil strength, design earth pressures, erosion,and stability. Design and performance issues with respect to moisture as it relates to the structure environment (i.e., humidity, mildew, mold) is beyond Terra Associates' purview. A building envelope specialist or contractor should be consulted to address these issues, as needed. 3.0 SITE CONDITIONS 3.1 Surface The project site consists of 7 tax parcels totaling approximately 12.7 acres located adjacent and southwest of the intersection of SE 136th Street and 143rd Avenue SE in Renton, Washington. The approximate site location is shown on Figure 1. With the exception of the eastern parcel the property is developed with single-family residences along with several outbuildings. The areas immediately surrounding the residences are landscaped with lawns and associated bushes and flower beds. The eastern parcel is undeveloped and has a drainage that meanders through the property from the northwest to the southeast. In the southeastern corner of the property the drainage becomes incised creating a deeper ravine feature. Elevation relief from the top of the ravine to the base of the drainage is on the order of 14 to 20 feet carried over slope gradients of about 50 percent. This portion of the site is moderately forested with associated understory. Elsewhere the site topography is generally flat with slight elevation undulations. 3.2 Subsurface Soil conditions we observed in the test pits generally consisted of 6 to 12 inches of organic topsoil overlying 2 to 5 feet of inedium dense silty sand with gravel(weathered till)overlying dense to very dense silty sand with gravel (unweathered glacial till) to the ternunation of the test pits. A thicker organic topsoil layer (18 inches) was observed overlying these native till soils at Test Pit TP-9. We also observed about 18 inches of silty sand fill material below 6 inches of gravelly topsoil at Test Pit TP-7. We would expect other areas of shallow surface fills associated with the existing developed parcels will be present. Page No. 2 February 10, 2014 Revised February 10, 2015 Project No.T-6995 The Geologic Map of The Renton Quadrangle, Ki�Tg County by D.R. Mullineaux (1965) maps the site as Ground moraine deposits consisting of a thui layer of ablation till overlying lodgment till (Qgt). Soil conditions observed in the test pits are generally consistent with the mapped geology. The preceding discussion is intended to be a general revie�v of the soil conditions encountered. For more detailed descriptions,please refer to the Test Pit Logs in Appendix A. 3.3 Groundwater We observed groundwater seepage at Test Pits TP-3, TP-4, and TP-5 during our exploration. The seepage was observed at a depth of about four feet below cunent site grades at the contact between the upper weathered and lower unweathered till soils. This shaliow groundwater seepage is common on glacial till sites and is the result of precipitation infiltrating the upper more pen�ious weathered till soil and becoming perched on top of the less pervious unweathered till. The seepage is seasonal and will fluctuate depending on rainfall amounts. This seepage typically diminishes with the onset of the nornially drier sununer months and often times is absent in the fall time of the year. 4.0 GEOLOGICAL HAZARDS 4.1 Seismic Considerations Section 4-3-OS J.l.d. of the Renton Municipal Code (RMC) defines a seismic hazard as " i. Low Seismic Hazard (SL): Areas underlain by dense soils or bedrock. These soils generally have site coefficients of types S 1 or S2, as defined in the International Building Code. ii. High Seismic Hazard (SH): Areas underlain by soft or loose. saturated soils. These soils generally have site coefficients of types S3 or S4, as detined in the Internatiorial Building Code. (Ord. 5450, 3-2-2009)" Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength due to an increase in water pressure induced by vibrations. Liquefaction mainly affects geologically recent deposits of fine-grained sand that is below the groundwater table. Soils of this nature derive their strength from intergranular friction. The generated water pressure or pore pressure essentially separates the soil grains and elinunates this intergranular friction; thus,eliminating the soiPs strength. Based on the soil conditions we observed and the absence of a shallow goundwater table, in our opinion, the risk for liquefaction to occur at this site during an earthquake is negligible. The soils are dense and, therefore the site is a Low Seismic Hazard per the RMC. Based on soil conditions observed in the test pits and our knowledge of the area geology, per Chapter 16 of the 2012 International Building Code (IBC), site class "C" should be used in structural design. Based on this site class, in accordance with the 2012 IBC,the following parameters should be used in computing seismic forces: Seismic Design Paranreters(IBC 2012) S ectral res onse acceleration(Short Period), SA1s 1.378 Spectral response acceleration(1 —Second Period), SM� 0.676 Five ercent dam ed .2 second eriod, Sps 0.925 Five ercent dam ed 1.0 second eriod, SD� 0.451 Values deternuned using the United States Geological Survey (USGS) Ground Motion Parameter Calculator accessed on February 9, 2015 at the web site http://earthquake.usgs.gov/desigiunaps/us/application.php. Page No. 3 February 10, 2014 Revised February 10, 20l 5 Project No. T-699� 4Z Erosion Hazard Areas Section 4-3-OS J.c. of the RMC defines an erosion hazard as "i. Low Erosion Hazard (EL): Areas with soils characterized by the Natural Resource Conservation Service(formerly U.S. Soil Conservation Service) as having slight or moderate erosion potential, and that slope less than 15 percent. ii.High Erosion Hazard (EI�: Areas with soils characterized by the Natural Resource Consenration Service (formerly U.S. Soil Conservation Service) as having severe or very severe erosion potential,and that slope more steeply than 15 percent." The majority of the soils observed on-site are classified as Alderwood gravelly sandy loam 6 to 15 percent slopes by the United States Department of Agriculture Natural Resources Conservation Service (NRCS), formerly the Soil Conservation Service. Soils on the steep ravine slopes located in the southeastern portion of the site are classified as Alderwood very steep. Over most of the site with the existing slope gradients, these soils will have a slight to moderate potential for erosion when exposed. Therefore, with the exception of the steeper ravine slopes the site is a Low Erosion Hazard area per the RMC. The steep ravine slopes would be considered a High erosion hazard area per the R'VIC. Regardless, erosion protection measures as required by tlie City of Renton will need to be in place prior to starting grading activities on the site. This would include perimeter silt fencing to contain erosion on-site and cover measures to prevent or reduce soil erosion during and following construction. 4.3 Landslide Hazard Areas Section 4-3-OS J.b. of the RMC defines a landslide hazard area as "i. Lo« Laridslide Hazard (LL): Areas with slopes less than 15 percent. ii. Medium Landslide Hazard (LM): Areas with slopes between 15 percent and 40 percent and underlain by soils that consist largely of sand, gravel or glacial till. iii. High Landslide Hazard (LH): Areas with slopes greater than 40 percent, and areas with slopes between 15 percent and 40 percent and underlain by soils consisting largely of silt and clay. iv. Very High Landslide Hazards (LV): Areas of known mappable landslide deposits. " Because of the slope gradient the drainage ravine slopes located in the southeastern portion of the site would be categorized as a High Landslide Hazard area by the RMC. Appropriate building setbacks and buffers as discussed in the following sections of this report will need to be implemented to prevent impacts to the slopes and attendant properties. 5.0 DISCUSSION AND RECOMMENDATIONS 5.1 General Based on our study, there are no geotechnical considerations that would preclude development of the site, as currently planned. Residences can be supported on conventional spread footings bearing on competent native soils observed below the upper 12 inches of organic surface soil or on structural fill placed and compacted above these native soils. Pavement and floor slabs can be similarly supported. Page No. 4 February 10, 2014 Revised February 10, 2015 Project No.T-6995 The native soils encountered at the site contain a significant amount of fines and will be difficult to compact as structural fill when too wet. The ability to use native soil from site excavations as structural fill will depend on its moisture content and the prevailing weather conditions at the time of construction. If grading activities will take place during winter, the o���iier should be prepared to iinport clean granular material for use as structural fill and backfill. The following sections provide detailed recommendations regarding the preceding issues and other geotechnical design considerations. These recommendations should be incorporated into the final design drawings and construction specifications. 5.2 Site Prenaration and GradinQ To prepare the site for construction, all vegetation, organic surface soils, and other deleterious material should be stripped and removed from below the building lots and roadway areas. Generally, surface stripping depths of approximately 8 to 12 inches should be expected to remove the organic surface soils. Deeper stripping approaching 18 inches should be expected in areas such as in the vicinity of Test Pit TP-9. In the developed portions of the site, demolition of existing structures should include removal of existing foundations and abandonment of underground septic systems and other buried utilities. Abandoned utility pipes that fall outside of new building areas can be left in place provided they are sealed to prevent intrusion of groundwater seepage and soil. Organic topsoil will not be suitable for use as structural fill, but may be used for limited depths in nonstructural areas. Once clearing and stripping operations are complete, cut and fill operations can be initiated to establish desired grades. Prior to placing fill, all exposed bearing surfaces should be observed by a representative of Terra Associates to verify soil conditions aze as expected and suitable for support of new fill. Our representative may request a proofmll using heavy rubber-tired equipment to determine if any isolated soft and yielding areas are present. If excessively yielding areas are observed, and they cannot be stabilized in place by compaction, the affected soils should be excavated and removed to fum bearing and grade restored with new structural fill. Beneath embankment fills or roadway subgrade if the depth of excavation to remove unstable soils is excessive, the use of geotextile fabrics, such as Mirafi SOOX, or an equivalent fabric, can be used in conjunction with clean granular structwal fill. Our experience has shown that, in general, a minimum of 18 inches of a clean, granular structural fill placed and compacted over the geotextile fabric should establish a stable bearing swface. The native soils encountered at the site contain a sufficient amount of soil fines that will make them difficult to compact as structural fill when too wet or too dry. The ability to use native soils from site excavations as structural fill will depend on its moisture content and the prevailing weather conditions at the time of construction. When wet soils are encountered, the contractor will need to dry the soils by aeration during dry weather conditions. Altematively, the use of an additive such as Portland cement or lime to stabilize the soil moisture can be considered. If the soil is amended, additional Best Management Practices (BMPs)addressing the potential for elevated pH levels will need to be included in the Storm Water Pollution Prevention Program (SWPPP)prepared with the Temporary Erosion and Sedimentation Control (TESC)plan. Page No. 5 February 10,2014 Revised February 10, 2015 , Project No.T-6995 If grading activities are planned during the wet winter months, or if they are initiated during the summer and extend into fall and winter,the owner must be prepared to import wet weather structural fill. For this purpose,we recoitunend importing a granular soil that meets the following grading requirements: U.S. Sieve Size Percent Passing 6inches 100 No.4 75 maximum No. 200 5 inaximum* * Based on the 3/4-inch fraction. Prior to use, Terra Associates, Inc. should examine and test all materials imported to the site for use as structural fill. Structural fill should be placerl in uniform loose layers not exceeding 12 inches and compacted to a minimum of 95 percent of the soil's maximum dry density, as determined by American Society for Testing and Materials (ASTM)Test Designation D-698 (Standard Proctor). The moisture content of the soil at the time of compaction should be within minus one to plus three percent of its optimum, as deternuned by this ASTM standard. In nonstructural areas,the degree of compaction can be reduced to 90 percent. 5.3 Excavatioa All excavations at the site associated with confined spaces, such as utility trenches, must be completed in accordance with local, state, and federal requirements. Based on regulations outlined in the Washington Industrial Safety and Health Act (WISHA), the upper two to five feet of weathered native soils and existing fill soils would be classified as Type C soil. The dense native soils below four feet would be classified as Type A soil. Accordingly, temporary excavations in Type C soils should have their slopes laid back at an inclination of 1.5:1 (Horizontal:Vertical) or flatter, from the toe to the crest of the slope. Side slopes in Type A soils can be laid back at a slope inclination of 0.75:1 or flatter. For temporary excavation slopes less than 8 feet in height in Type A soils, the lower 3.5 feet can be cut to a vertical condition, with a 0.75:1 slope graded above. For temporary excavation slopes greater than eight feet in height,the slope above the 3.5-foot vertical portion will need to be laid back at a minimum slope inclination of 1:1. All exposed temporary slope faces that will remain open for an extended period of time should be covered with a durable reinforced plastic membrane during construction to prevent slope raveling and rutting during periods of precipitation. The above infonnation is provided solely for the benefit of the owner and other design consultants, and should not be construed to imply that Terra Associates, Inc. assumes responsibility for job site safety. It is understood that job site safety is the sole responsibility of the project general contractor. 5.4 Slopes and Embankments All permanent cut and fill slopes should be graded with a finished inclination of no �-eater than 2:1. Upon completion of grading, the slope face should be appropriately vegetated or provided with other physical means to b ard against erosion. Final grades at the top of the slope must promote surface drainage away from the slope crest. Water tnust not be allowed to flow uncontrolled over the slope face. If surface runoff must be directed towards the slope,the runoff should be controlled at the top of the slope,piped in a closed conduit installed on the slope face, and taken to an appropriate point of discharge beyond the toe. Page No. 6 February 10, 2014 Revised February 10,2015 Project No.T-6995 5.5 Foundation Support The residences can be supported on conventional spread footing foundations bearing on competent native soils, competent existing fill soils, or on structural fills placed above competent soils. Foundation subgrade should be prepared as recommended in Section 5.2 of tivs report. Perimeter foundations exposed to the weather should bear a minimum depth of 1.5 feet below final exterior grades for frost protection. Interior foundations can be constructed at any convenient depth below the floor slab. Foundations bearing on competent native soils, competent existing fill soils, or on compacted structural fill can be dimensioned for a net allowable bearing capacity of 2,500 pounds per square foot (ps fl. For short-term loads, such as wind and seismic, a one-third increase in this allowable capacity can be used. With structural loading as anticipated and tlus bearing stress applied, estimated total settlements are between one-quarter and one-half inch. For designing foundations to resist lateral loads, a base friction coefficient of 0.35 can be used. Passive earth ' pressures acting on the side of the footing and buried portion of the foundation stem wall can also be considered. We recoirunend calculating this lateral resistance using an equivalent fluid weight of 350 pcf. We recommend not including the upper 12 inches of soil in this computation because they can be affected by weather or disturbed by future grading activity. This value assumes the foundation will be constructed neat against competent native soil or backfilled with structural fill as described in Section 5.2 of this report. The values recommended include a safety factor of 1.5. 5.6 Floor Slab-on-Grade Slab-on-grade floors may be supported on subgrade prepared as recommended in Section 5.2 of this report. Inunediately below the floor slab, we recommend placing a four-inch thick capillary break layer composed of clean, coarse sand or fine gravel that has less than three percent passing the No. 200 sieve. This material will reduce the potential for upward capillary movement of water through the underlying soil and subsequent wetting of the floor slab. The capillary break layer will not prevent moisture intrusion through the slab caused by water vapor transmission. VVhere moisture by vapor transmission is undesirable, such as covered floor areas, a common practice is to place a durable plastic membrane on the capillary break layer and then cover the membrane with a layer of clean sand or fine gravel to protect it from damage during construction, and to aid in uniform curing of the concrete slab. It should be noted that if the sand or gravel layer overlying the membrane is saturated prior to pouring the slab, it will not be effective in assisting uniform curing of the slab and can actually serve as a water supply for moisture bleeding through the slab, potentially affecting floor coverings. Therefore, in our opinion, covering the cnembrane with a layer of sand or gravel should be avoided if floor slab construction occurs during the wet winter months and the layer cannot be effectively drained. We recommend floor designers and contractors refer to the 2003 American Concrete Institute (ACI) Manual of Concrete Practice, Part 2, 302.1 R-96, for further information regarding vapor banier installatiou below slab-on-grade floors. 5.7 Stormwater Detention Pond A stormwater detention pond will be constructed in the southeast corner of the development. The proposed pond floor will be 14 to 20 feet below current site grades and formed by a combination of excavation and fill containrnent benn construction. Page No. 7 February 10, 2014 Revised February 10, 2015 Project No.T-6995 Our field exploration indicates that the soils in the area of the ponds will be medium dense to very dense weathered and unweathered glacial till. These soil conditions exhibit low permeability and are inherently stable and well suited for construction of stormwater detention ponds. Fill used to form containment berms and construct slopes for the detention ponds should consist of native silty sand with gravel placed and compacted as structural fill. If requirements of the King County Surface Water Design Manual apply, the fill in this area must be compacted to a minimum of 95 percent of the soils maximum dry density as deternuned by ASTM Test Designation D-1557 (Modified Proctor). Interior pond slopes below the maximum live stored water level should be graded to a maximum slope inclination of 3:1. Slopes above the maximum stored water level or on the pond exterior can be graded to a finished slope inclination of 2:1. The pond that is located northwest of the drainage ravine could, as a result of seepage from the pond, cause shallow soil instability on the ravine slopes. The potential for this development will be dependent on the pond stored water depth and distance from the ravine slopes. At minimum, we recommend the pond design provides a 50-foot horizontal setback distance from the edge of the maximum stored water elevation in the pond to the crest of the ravine slope. Based on the "Drainage Facility Plan and Details" prepared by Barghausen Consulting Engineers dated October 8, 2014, a 50-foot setback from the top of the slope to the top of the pond has been incorporated into the placement and design of the pond. Maximum stored water depth is at elevation 384. The top of the pond at the closest point to the slope is at elevation 386. 5.8 Rockery A rockery is not intended to function as an engineered structure to resist lateral earth pressure as a retaining wall , is. The primary function of a rockery is to cover the exposed soil face to reduce the potential for erosion. All rockery construction should conform to the Associated Rockery Contractors (ARC) Standard Rock Wall Construction Guidelines. We recommend limiting cut rockeries to a height of eight feet when facing undisturbed dense native soils. Where buildings will be constructed above and adjacent to rockery construction, the foundations should be lowered to prevent surcharge loading on the rockery. Foundation depths should provide for a theoretical 1:1 influence line extending from the footing edge to pass beneath the rockery base. A detail illustrating a typical cut rockery is presented on Figure 4. 5.9 Drainage Surface Final exterior grades should promote free and positive drainage away from the site at all times. Water must not be allowed to pond or collect adjacent to foundations or within the immediate building areas. We recommend providing a positive drainage gradient away from the building perimeters. If this gradient cannot be provided, surface water should be collected adjacent to the structures and disposed to appropriate storm facilities. Surface water must not be allowed to flow uncontrolled over the crest of the site slopes and embankments. Surface water should be directed away from the slope crests to a point of collection and controlled discharge. If site grades do not allow for directing surface water away from slopes, then water should be collected and tightlined down the slope face in a controlled manner. Page I�'o. 8 February 10, 2014 Revised February 10, 2015 Project No.T-6995 Subsurface � We recommend installing perimeter foundation drains adjacent to shallow foundations. The drains can be laid to I', grade at an invert elevation equivalent to the bottom of footing grade. "The drains can consist of four-inch ' diameter perforated PVC pipe that is enveloped in washed pea gravel-sized drainage aggregate. The aggregate ', should extend six inches above and to the sides of the pipe. Roof and foundation drains should be tightlined separately to the storm drains. All drains should be provided with cleanouts at easily accessible locations. Irifiltration As described earlier, the glacial till soils observed in the test pits contain a high percentage of soil fines, are well consolidated, and exhibit low permeability. The soils and geologic formation are not suitable for discharge of stormwater using facilities that rely on infiltration. 5.10 Utilides Utility pipes should be bedded and backfilled in accordance with American Public Works Association(APWA)or the City of Renton specifications. As a minimum, trench backfill should be placed and compacted as structural fill, as described in Section 5.2 of this report. As noted, depending on the soil moisture when excavated most inorganic native soils on the site should be suitable for use as backfill material during dry weather conditions. However, if utility construction takes place during the wet winter months, it will likely be necessary to iinport suitable wet weather fill for utility trench backfilling. 5.11 Pavement Pavement subgrade should be prepared as described in the Se�tion 5.2 of this report. Regardless of the degree of relative compaction achieved, the subgrade must be firm and relatively unyielding before paving. The subgrade should be proofrolled with heavy rubber-tire construction equipment such as a loaded 10-yard dump truck to verify this condition. The pavement design section is dependent upon the supporting capability of the subgrade soils and the traffic conditions to which it will be subjected. For residential access, with traffic consisting mainly of light passenger vehicles with only occasional heavy traffic,and with a stable subgrade prepared as recommended, we recommend the following pavement sections: • Two inches of hot mix asphalt(HMA)over four inches of crushed rock base(CRB} � Three and one-half inches of full depth HMA The paving materials used should conform to the Washington State Department of Transportation (WSDO"I� specifications for'/z-inch class HMA and CRB aggregate. Long-term pavement perforrnance will depend on surface drainage. A poorly-drained pavement section will be subject to premature failure as a result of surface water infiltrating into the subgrade soils and reducing their supporting capability. For optimum pavement performance, we recommend surface drainage gradients of at least two percent. Some degree of longitudinal and transverse cracking of the pavement surface should be expected over time. Regular maintenance should be planned to seal cracks when they occur. Page No. 9 February 10, 2014 Revised February 10, 2015 Project No. T-6995 6.0 ADDITIONAL SERVICES Terra Associates, Inc. should review the final design drawings and specifications in order to verify that earthwork and foundation recommendations have been properly interpreted and implemented in project design. We should also provide geotechnical service during construction to observe compliance with our design concepts, specifications, and recommendations. This will allow for design changes if subsurface conditions differ from those anticipated prior to the start of construction. 7.0 LIMITATIONS We prepared this report in accordance with generally accepted geotechnical engineering practices. No other warranty, expressed or implied, is made. This report is the copyrighted property of Terra Associates, Inc. and is intended for specific application to the Copperwood project. This report is for the exclusive use of Quadrant Homes and its authorized representatives. The analyses and recommendations present in this report are based on data obtained from the test pits excavated I on site. Variations in soil conditions can occur, the nature and extent of which may not become evident until I construction. If variations appear evident, Terra Associates, Inc. should be requested to reevaluate the ' recommendations in this report prior to proceeding with construction. ' Page No. 10 ,V ........... . .«�. _" ,� °� 8�'as;a-Ne�tor � . (soo; r i D � (Nwer WI I�a�er� SL 117ti `_<t _ m " li�qh Schoo) :� I t?�•,c� _ > � Mati a - - Aluance = .; � hf U�• �C� ,f : 'r.� tit y�' ; z N�i pth St o � L = L - v: 9th St - — e � a Krwanrs('ark �ti > ,� � Celebratior � - r,F arr �• � v� i our5quare C'�urch = _ � :`J� iUt t I �,Z. t _ � Nl • ' rn ro °n, _ � 'J�6th St g kF blh S' NE b:��St � � r RF Srn 5• �9 z i .`' a Henton lech�ical Coliege c = Henton Christien Greenrrood Memo•�al A1E 4th St ; +� I ellowsFnp NC dtli St d � ItiPrK f Ur1Pr�il I•ome z , lora o+�i�e �� r s ���_ �•��i L.ir�e�an Chur � � � 7 Ji�+i I•ei�d{�x�lemorial �#errtage 1'atk �� ; 'J. :•,c!'it �l I i.'n�t�r � z t � � � ., SITE - _ ,- ?,,,_��; D s � SE 2rxi 1�1 � � � 5013 SE 2nd PI � '� �-�, n S�9ti'�✓ .. � �t�,'. 5 � �I 5!h,�� 4� �.11`�`�„ � � N ':h��i�t = Map!ewoad Park s� !aarh s ar�k �� 5� ■ m�s �r ` :� ' ��� � i • .,( S/ . , ,"S- ''.51 Ron Reg�s Park ..• y / c c �orL,s Ad 3 � 1/ ,y�� ��r, l,� s'` a •�� ��lh �rlfany na�k d ' • � New Li{e Chu� ,n At Renton SF�58th gr S� ������� � :�F�60th 5t � T .c, f�, 0 200o a000 s t Cascade Yark ��"•- Z �= !�.a��s, ```.,.,Y APPROXIMATE SCALE IN FEET u:,��:,. REFERENCE: GOOGLE MAPS 2/10/2014 � � Terra VICINITY MAP , •• Associates Inc. COPPERWOOD RENTON, WASHINGTON Consultants in Geotechnical�ngineering Geology and Environmental Eanh Saences Proj. No.T-6995 Date FEB 2015 Figu�e 1 i I � � � , �� , r _ ..4 � � r .. � , �+ � �'� � rave � �t S SITE , � ,� �`` d � ' 6g1 �" . , � > --; ,. o � Hei -� , �-- o� , g � , ; .� ; - . � . - � . . �_ _,. J � � '� � � � Q � � � r../ , , .- � �, , . f 4 I ' ' j 4 I � �1 \ � �. \ .. __ , �. � r- -6 , . . , �,1 .{ ; -- -- ``�- � _ _- � ....1 � ,,�..�� ' .�/' APPROXIMATE SCALE: 1:10000 1000 0 1000 2000 3000 4000 5000 6000 7000 FEET 1 t/2 0 11i1E CONTOUR INTERVAL: 65 FEET � REFERENCE: USGS MAPS, TACOMA, WASHINGTON QUADRANGLES 1991 � Terra TOPOGRAPHIC VICINITY MAP COPPERWOOD Associates I11C. 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RENTON, WASHINGTON • Consultants in Geotechnical�ngineering Geology and pro No.T-6995 Date FEB 2015 Fi ure 3 Environmental Earth Sciences 1• 9 ,,� z \/�.� . %A� `!,'�.� .,,�, � � /\\��j�'y. . �,�%\���'/, ;�, i�%�,,.�\�i'i �.\.��,;;./�i;�, �` 1' COMPACTED SOIL r o �` I � 1 `, ; z a � 8'MAX 9 0 ' ,; o y o x � p ; CRUSHED ROCK FILTER MATERIAL,BETWEEN 2 0 �� AND 4 INCH SIZE WITH LESS THAN 2% FINES G � i BUI�DING LOT . ;�.� �r-��.<- ._.,;,h.- � 3"MIN 1.5'MIN �� �' GRAVEL BEDDING T•.� �:'•.li'�!i'.���`Z��: � .. �y FIRM UNDISTURBED 4"MINIMUM DIAMETER SOIL TO BE VERIFIED DRAIN PIPE SURROUNDED BY BY GEOTECHNICAL ENGINEER CLEAN WASHED 3/4"DRAIN KEYWAY �M�N� POINT OF DISCHARGE KEYWAY SHOULD BE SLOPED DOWN TOWARDS THE FACE BEING PROTECTED NOT TO SCALE ROCKERY NOTES 1. REFER TO CIVIL GRADING DRAWINGS FOR WALL ALIGNMENTS AND ELEVATIONS. 2.ROCKERY CONSTRUCTION SHALL BE COMPLETED IN ACCORDANCE WITH THE ASSOCIATION OF R ROCKERY CONTRACTORS GUIDELINES. I 3. ROCK USEQ MUST MEET THE REQUIREMENTS FOR ROCK QUALITY SPECIFIED IN SECTIONS 9-13.7(1) OF THE WSDOT STANDARDS SPECIFICATIONS(2008). 4.ALL CAP ROCKS MUST BE SECURE AND NOT ABLE TO BE DISLODGED BY HAND. ���:� Terra CUT ROCKERY DEAIL COPPERWOOD ••• •�• Associates, It1C. RENTON, WASHINGTON Consultants in Geotechnical Engineering �eoio9y and Pro No.T-6995 Date FEB 2015 Fi ure 4 ' Environmental Earth Sciences 1• 9 APPENDIX A FIELD EXPLORATION AND LABORATORY TESTING Copperwood � Renton,Washington I On January 17, 2014, we completed our site exploration by observing soil conditions at 11 test pits. The test pits were excavated using a trackhoe to a maximum depth of ten feet below existing site grades. Test pit locations were determined in the field by measurements from existing site features. The approximate location of the test pits is shown on the attached Exploration Location Plan, Figure 2. Test Pit Logs are attached as Figures A-2 through A-12. A geologist from our office conducted the field exploration. Our representative classified the soil conditions encountered, maintained a log of each test pit, obtained representative soil samples, and recorded water levels observed during excavation. All soil samples were visually classified in accordance with the Unified Soil Classification S}stem(USCS)described on Fiwre A-1. Representative soil samples obtained from the test pits ���ere placed in closed containers and taken to our laboratory for further examination and testing. The moisture content of each sample was measured and is reported on the individual Test Pit Logs. Grain size analyses were performed on selected samples. The results of the�rain size analyses are shown on Figures A-13 tluough A-15. Project No. T-6995 MAJOR DIVISIONS LETTER nPICAL DESCRIPTION SYMBOL Clean GW Well-graded gravels,gravel-sand mixtures, IitUe or no fines. Gravels(less ` GRAVELS than 5% � � More than 50% fines) GP PO��Y-9raded gravels,gravel-sand mixtures,little or no fines. � m N of coarse fraction v) � �N is larger than No. GM Silty gravels,gravel-sand-silt mixtures, non-plastic fines. � c� > 4 sieve Gravels with Z i� •°—�� fines GC Clayey gravels,gravel-sand-clay mixtures,plastic fines. E � o N � � o Clean Sands SW Well�raded sands,sands with gravel,little or no fines. � � Z SANDS (less than QY L More than 50% 5%fines) Sp Poorly-graded sands,sands with gravel,little or no fines. v o Y of coarse fraction � is smaller than Sands with SM Silty sands, sand-silt mixtures, non-plastic fines. No. 4 sieve �nes SC Clayey sands, sand-clay mixtures,plastic fines. � (�� Inorganic silts, rock flour,clayey silts with slight plasticity. m °' SILTS AND CLAYS � �' 'N o CL Inorganic clays of low to medium plasticity.(Lean Gay) p �o � Liquid Limit is less than 50/o G c��o '�i OL Organic silts and organic clays of low plasticity. Z Eo 00 � � o MH Inorganic silts,elastic. � � Z SILTS AND CLAYS w � � o CH Inorganic clays of high plasticity.(Fat clay) Z L Liquid Limit is greater than 50/o � � .. o p�-{ Organic clays of high plasticity. � HIGHLY ORGANIC SOILS PT Peat. DEFINITION OF TERMS AND SYMBOLS N Standard Penetration � 2^OUTSIDE DIAMETER SPILT SPOON SAMPLER W Densi Resistance in Blows/Foot p Very Loose 0-4 � 2•4"INSIDE DIAMETER RING SAMPLER OR cA Loose 4-10 SHELBY TUBE SAMPLER = Medium Dense 10-30 1 WATER LEVEL(Date) O Dense 30-50 V Very Dense >50 Tr TORVANE REAOINGS,tsf Standard Penetration Pp PENETROMETER READING,tsf Consistancy Resistance in Blows/Foot � DD DRY DENSITY, pounds per cubic foot = Soft S�� 2-4 LL LIOUID LIMIT,percent O Medium Stiff 4-8 V Stiff g_�g PI PLASTIC INDEX Very Stiff 16-32 � Hard >32 N STANDARD PENETRATION,blows per foot �� Terra UNIFIED SOIL CLASSIFICATION SYSTEM COPPERWOOD Associates I11C. RENTON, WASHINGTON .. Consultants in Geotechnical�ngineering Geology and Pro No.T-6995 Date FEB 2015 Fi ure A-1 Environmental Earth Saences 1• 9 LOG OF TEST PIT NO. TP-1 FIGURE A-2 PRWECT NAME: Conoerwood PROJ.NO: T-6995 LOGGED BY: JH LOCATION: Renton ashington SURFACE CONDS: Grasses APPROX.ELEV: DATE LOGGED: Janua 7.2014 DEPTH TO GROUNDWATER: N/A DEPTH TO CAVING: 1�/A d � z W CONSISTENCY! � � DESCRIPTION RELATIVE DENSITY � REMARKS W Q �' C fA (4 to 6 inches ORGANIC TOPSOIL) •----------------•-•--------------------•--•-•-----------------•-----------•----•---------------•--- --------------------------••-- � � Daric brown sifty SAND,fine to medium grained,trace gravel,occasional cobble to 8 inches,moist. (SM) 2 (Weathered till) Medium Dense 21.1 , 3 4 -------•--------------•--•----------------•-----_..---•••--•------•------------...-- •----------•----._...•-•----••- 7.9 5 Gray silty SAND,fine to medium grained,trace gravel, p�se to cobbles to 8 ind�es. (SM) (Till) Very Dense 6 7 Test pit tertninated at approximately 7 feet. No groundwater seepage observed. 8 9 10 Terra NOTE: This subsurface i�fonnation pertains only to ihis test pit locat'an and should Associates, �I1C. not be interpreted as being indicative of other bcatlons at the site. Consuttants in Geotechnical Engineering Geology and Environmental Earth Stiences LOG OF TEST PIT NO. TP-2 FIGURE A-3 PROJECT NAME: CoQnervvood PROJ.NO: T-6995 LOGGED BY: JH LOCATION: Renton.Washington SURFACE CONDS: Grasses APPROX.ELEV: DATE LOGGED: Januarv 7 2014 DEPTH TO GROUNDWATER: N/A DEPTH TO CAVING: N/A ^ o � �++ CONSISTENCYf � DESCRIPTION 3e REMARKS a RELATIVE DENSITY w < 3 O d> (2 to 4 inches dark ORGANIC TOPSOIL) ..•••••----------------••••••---- ------------••------------------------•-•----------------�-------------------------•---------•-- Dark brown silty SAND,fine grained,trace gravel,moist. (SM) (Weathered till) 1 Medium Dense I ..__—_--------------------------------------•-••-----------------...--•----------------•--••• -•-•------------------------- 21.6 2 3 Dense to Gray silry SAND,fine grained,trace gravel,moist. Very Dense (SM) (Till) 4 22.5 5 6 7 8 Test pit terminated at approximately 8 feet. No groundwater seepage observed. 9 10 Terra NOTE: This subsurface i�ortnadon pertalns only to this lest pit location and should ASSOCIat@S, �t1C. not be interpreted as being indicative ot other bcations at the site. Consultants in Geotechnical Engineering Geology and Ernironmental Earth Sciences LOG OF TEST PIT NO. TP-3 FIGURE A-4 PROJECT NAME: CoDnervvood PROJ.NO: T-6995 LOGGED BY: JH I LOCATION: Renton.Washington SURFACE CONDS: Grasses APPROX.ELEV: DATE LOGGED: Januarv 7.2014 DEPTH TO GROUNDWATER: 4 Feet DEPTH TO CAVING: N/A I 0 Vz F � DESCRIPTION CONSISTENCY! � REMARKS a RELATIVE DENSITY w < 3 o rn (4 to 6 inches dark ORGANIC TOPSOIL) --------------------�-�------------------------- ------------.__..�----------------- ---------••-••----•---•----------- 1 40.5 Brown silty SAND,fine to medium grained,trace gravel, Medium Dense 2 moist. (SM) (Weathered till) 3 = 4 --•---------•----•-••---------------•-•.....--------------•-•-••-•-------------_........---•--------- -------------.___..._--- 25.7 5 � Gray silty SAND,fine grained,trace gravel,moist. Dense to 12.3 g (SM) (Till) Very Dense 7 8 9 10 Test pit terminated at approximately 10 feet. Groundwater seepage observed at 4 feet. 11 12 13 14 15 �-----� Terra NOTE: This subsurface iniormation pertains ontyto this test pit IocaUon and should i Associates, �t1C. not be interpreted as being fndicalive ot other IocaGons at the site. ' Consultants in Geotechnical Engineering Geology and Environmental Earth Sciences � LOG OF TEST PIT NO. TP-4 FIGURE A-5 PROJECT NAME: Co�nerwood PROJ.NO: T-6995 LOGGED BY: JH LOCATION: Renton Washington SURFACE CONDS: Grasses APPROX.ELEV: DATE LOGGED: Januarv 7 2014 DEPTH TO GROUNDWATER: 4 Feet DEPTH TO CAVING: N/A 0 v Z � F � ' DESCRIPTION CONSISTENCY! e REMARKS a RELA7IVE DENSITY w ¢ 3 C N (6 inches TOPSOIL) -------------------- - --------------------------------------- -------------------------- ----•-•---•-•----------------- 1 Brown silty SAND,fine to medium grained,trace gravel, Medium Dense 36.4 2 cobbles to 8 inches,moist. (SM) (Till) 3 = 4 -------------------------------------------------------------•-••---------------------------• ----------------------------- 5 14.3 Gray silty SAND,fine to medium grained,trace gravel, g cobbles to 8 inches,moist. (SM) (Weathered till) 7 8 9 Test pit terminated at approximately 9 feet. Groundwater seepage observed at 4 feet. 10 11 12 13 14 15 !, �. Terra NOTE: This subsurface information pertains o�ly to this test pit Iocatfon and should ASSOC18t@S, �IIC. not be interpreted as being indicative ot other Iceations at the site. Consultants in Geolechnical Engineering Geology and Environmental Earth Sciences LOG OF TEST PIT NO. TP-5 FicuRe a-s , PROJECT NAME: CoR�erwood PROJ.NO: T-6995 LOGGED BY: JH li LOCATION: Renton,Washington SURFACE CONDS: Grasses APPROX.ELEV: DATE LOGGED: Januarv 7 2014 DEP7H TO GROUNDWATER: 3.5 Feet DEPTH TO CAVING: N/A v Z W coNsisreNcrr DESCRIPTION X REMARKS � � RELATIVE DENSITY w a 3 c �n (6 to 8 inches dark brown TOPSO�L) 1 Medium Dense Brown silty SAND,fine to medium grained,trace gravel, moist. (SM) (Weathered till) 2 22.6 3 : 4 •---------•-•--------------------------------------------------.__.._�-------------------- ---•----•--------------------•-- 5 Gray silry SAND,fine to medium�alned,trace gravel, Oense to 23.2 moist. (SM) (Till) Very Dense 6 7 Test pit tenninated at approximately 7 feet. Light groundwater seepage observed at 3.5 feet. 8 9 10 Terra NOTE: This subsurface infortnation pertains only to this test pt location and should ASSOCI1t@S, �I1C. not be interpreted as being indkative of other lotations at the site. Consultants in Geotechnical Engineering Geology and Emironmental Earth Scierxes LOG OF TEST PIT NO. TP-6 FIGURE A-7 PRWECT NAME: Co�nerwood PROJ.NO: T-6995 LOGGED BY: JH LOCATION: Renton Washinaton SURFACE CONDS: Grasses APPROX.ELEV: DATE LOGGED: Januarv 7 2014 DEPTH TO GROUNOWATER: WA DEPTH TO CAVING: N/A � d z W CONSISTENCYI a � DESCRIPTION RELATIVE DENSITY � REMARKS W ` 3 O N (4 to 6 inches TOPSOIL) --------------•----------•-----------------•------...---------------------------------...-•-----•---- -------------------...---------- 1 Dark broMrt�sily SAND,fine grained,trace gravet,mast 2 to wet. (SM) (Weathered till) Medium Dense 20.3 3 4 5 ------------------_.__---------___..__ ._._-------- -------_______------ Gray silty SAND,fine grained,trace gravel and cobble, s moist to wet. (SM) (Till) Dense to 46.1 Very Dense 7 8 Test pit tertninated at appropmately 8 feet. , No groundwater seepage obseroed. 9 10 _ �� Terra NOTE: This subsurface information peRains only to this test pit bcation and should ASSOCIBt@S, �(lC. not be interpreted as being indicative oi other locations at the site. Consultants in GeotecMical Enginee�ng Geology and Erniro�mental Earth Sciences I LOG OF TEST PIT NO. TP-7 FIGURE A-8 PROJECT NAME: C�onerwood PROJ.NO: T-6995 LOGGED BY: JH LOCATION: Renton.Washin�on SURFACE CONDS: Grasses APPROX.ELEV: DATE LOGGED: Januarv 7.2014 DEPTH TO GROUNDWATER: N/A DEPTH TO CAVING: WA � i � DESCRIPTION CONSISTENCY! � REMARKS � � RELATIVE DENSITY W < 3 c ar� (4 to 6 inches daric GRAVEL TOPSOIL) -----�----------------------•-••----------------------...•-----------....-------------------------- ----------------•---------------•- 1 FILL:brown silty sand,fine grained,Vace gravel,plastic Medium Dense and brick. 11.5 2 ------------•--------------...._----------•••••••--•-------•-----•---•-------------------•--------- ----------------------------- 3 Dense to 21.7 q Gray silty SAND,fine grained,trace gravel,moist. (SM) Very Dense (Till) 5 � 6 7 8 19.5 9 10 Test pit terminated at approximately 10 feet. No groundwater seepage observed. 11 12 13 14 15 Terra NOTE: This subsurface informatlon pertains only to this lest pit location and should /4.SSOC18t@S, ��1C. not be interpreted as being indicative oi other bcations at the site. ConsuNants in Geotechnical Engineering Geology and Environmental EaRh Sciences LOG OF TEST PIT NO. TP-8 FIGURE A-9 PROJECT NAME: Copnerwood PROJ.NO: T-6995 LOGGED BY: JH LOCATION: Renton.Washinaton SURFACE CONDS: Grasses APPROX.ELEV: DATE LOGGED: Januarv 7.2014 DEPTH TO GROUNDWATER: N/A DEPTH TO CAVING: N/A vZ F � DESCRIPTION CONSISTENCY! e REMARKS a RELATIVE DENSITY w a 3 o � (10 inches dark brown TOPSOIL) --•---------------------•--------------------------------------------------------------------- ----------------•-----------•---- 1 22.5 2 Brown silty SAND,trace gravel,moist. Medium Dense {SM) (Weathered till) 3 4 5 •--•-----•-•--------••---.....---------------•-------------•--------------------------- --•-----•----•-•---------------- 6 Gray silty SAND,trace gravel,trace cobble,moist. Dense to (SM) (Till) Very Dense 7 � 18.0 8 Test pit terminated at approximately 8 feet. No groundwater seepage observed. 9 10 Terra NOTE: This subsurface iniormation pertains only to this test pit location and should ASSOCIBt@S, �I1C. not be interpreted as being irxlicative oi other locations at the site. Consuitants in Geotechnical Engineering Geology and Environmental EaAh Sciences LOG OF TEST PIT NO. TP-9 FIGURE A-10 PROJECT NAME: CoRpervvood PROJ.NO: T-6995 LOGGED BY: JH LOCATION: Renton.Washington SURFACE CONDS: Grasses APPROX.ELEV: DATE LOGGED: January 7 2014 DEPTH TO GROUNDWATER: N/A DEPTH TO CAVING: N/A — o � LL Z x -W+ DESCRIPTION CONSISTENCYI e REMARKS a � RELATIVE DENSITY w < 3 o � (18 inches dark brown TOPSOIL) 1 2 20.4 Medium Dense 3 Gray to brown silty SAND,fine grained,trace gravel, moist. (SM) (Till) 4 5 6 Test pit terminated at approximately 6 feet. No groundwater seepage observed. 7 8 9 10 Terra NOTE: This subsurface informaGon pertains only to this test pit location and should /4.SSOC18t@S, �(1C. not be interpreted as being indicative of other locatans at ihe site. Consultants in Geotechnical Engineering Geology and Environmental EaM Sciences LOG OF TEST PIT NO. TP-10 FIGURE A-11 PROJECT NAME: Co��erwood PROJ.NO: T-6995 LOGGED BY: JH LOCATION: Renton.Washin9ton SURFACE CONDS: Grasses APPROX.ELEV: DATE LOGGED: Januarv 7.2014 DEPTH TO GROUNDWATER: N/A DEPTH TO CAVING: N/A d � _ CONSISTENCY/ a � DESCRIPTION RELATIVE DENSITY X REMARKS I w < 3 C N (12 inches dark brown TOPSOIL) 1 -----------------------__•-------------•--•-----•-•-------------•-------------------•--------- -------------------------------- 19.5 2 Daric brown silty SAND,fine grained,trace gravel,moist. (SM) (Weathered tili) Medium Dense 3 4 11.8 5 -------------•----•----------- 6 13.9 Gray silty SAND,fine grained,trace c,�avel,moist. (SM) (Till) Very Dense 7 8 9 Test pit terminated at approximate�y 9 feet. No groundwater seepage observed. 10 Terra NOTE: This subsu�face iniormation pertains only to this test pit location and should ASSOCI1t@S, �t1C. not be inte►preted as being indicative oi other locations at the site. Cortsultants in Geotechnical Engineering C,eology and Enviro�mental Earth Sciences LOG OF TEST PIT NO. TP-11 FIGURE A-12 PROJECT NAME: Coonerwood PROJ.NO: T-6995 LOGGED BY: _,!H LOCATION: Renton.Washin9ton SURFACE CONDS: Grasses APPROX.ELEV: DATE LOGGED: January 7.2014 DEPTH TO GROUNDWATER: N/A DEPTH TO CAVING: N/A 0 � _ x � DESCRIPTION CONSISTENCY! X REMARKS a � RELATiVE DENSITY � w < o w (12 inches dark brown TOPSOIL) 1 --------••-----••••----....•-•---------•-------••-•••--------••••••-•-••-----.._..--•--•••••••••-- -------------------------------- 16.0 2 Dark brown silty SAND,fine to medium grained,Vace Medium Dense graveUcobble,moist. (SM) (Weathered till) 3 4 5 15.0 Very Dense s Gray silty SAND,fine to medium grained,trace graveUoobble,moist. (SM) (Till) 7 8 9 10 Test pit terminated at approximately 10 feet. No groundwater seepage observed. 11 12 13 14 15 Terra NOTE: This subsurface information pertains only to this test pt IocaUon and should ASSOCIBt@S� �I1C. not be interpreted as being indicative of other bcations at the site. i Consultants in Geotechnical Ergineering Geology and Ernrirorxnental Earth Sciences � � � • ' • • �� �\�� ��',''. ♦ � ���. B�II�� .. : .�i�� . :, � �GII.. ,, �, ��� �`. , A��. �1►.\ . I.y� ��q �►. �., ., � ��i , ► . �►,: ,��� _� � iw�. ► . �� .� : �, b, , � � •-���� b�. i�� . _...: . Ilq , „ . . „ , .. . . . ��� =� �� � „ , , . . , , Q � � � � �i , � � , � � � � �� � . . 1/���� ' . � � ' � ' � �� ' � ���� 0�� , . .. ���_��� a��� � �.� �� � � ���� a�� .� , . , .. , , „ ���� : - � : . . � . . . • . � . - ■ � � - • � � - . . ��� � :� . � • �- • •��- ..� - � . � � •� • . . � _ . ■ � • � : � - ♦ � • ' � a • � � • • � Particle Size Distribution Report � � o < < < � � � � o 00(� 0Q (op g � g f0 N � \ \ f7 � ik it it it 7L i! ii A �0� I � I I , I I I I I ' I I I I I I I I I � I ' � I 90 � I I I I I I I I I I I I I I I I I I I I I I I I I I I $� I I I I I I I I � I � I I I I I I ( I I I I I I I I 7� � I I I I I I I I I I I I I I I I I I I I I I I I W 6� Z I I I I I I I I ' I I I I � I I ( I I I I f I I I Z 50 U � � � � � � � � � � � � � � � � � � � � � � � � � � � � w 40 a I I I I I I I I I I I I I I I I I I I I I I I I 30 I I I I I I I I I I I I I I I I I I I I I I ! I 20 I I I I I I I I I I I I I I I I I I I I I I I I I I I io I I I I I I I I I I I I I I I I I I I I I I I I I I I I 0 �oo �o i o.i o.oi o.00� GRAIN SIZE- mm. a�o+3„ %Gravel %Sand %Fines Coarse Fine Coarse' Medium Fine Silt Clay 0 0.0 2.4 15.1 83 23.1 31.1 20.0 ❑ 0.0 40.7 9.8 5.1 10.? � 16.2 17.5 0 0.0 OA 11.7 83 14.3 � 36.1 29.6 LL PL D D D D D D C C 0 5.9985 0.5851 0.4113 0.2168 ❑ 59.1490 25.2793 5.2022 0.2802 0 3.3745 0.3215 0.2114 0.0769 Material Description USCS AASHTO o Silty Sand with some gravel SM ❑ Sandy Gravel with Silt GM o Sil Sand with some ravel SM Project No. T-6995 Client: Quadrant Homes Remarks: Project: Copperwood Renton, Washington o Location: Test Pit TP-5 Depth: 5.5 feet ❑ Location: Test Pit TP-7 Depth: 1 foot o Location: Test Pit TP-8 Depth: 7 feet Terra Associates, Inc. Kirkland WA Figure A-14 Particle Size Distribution Report �O ('� N \ � \ \ f`� � ik ik # ?t ii � ik 3� 10Q I I I I � I I I I I I I I I I I I I I I I I I i I so , I I I I I I I I I I I I I I I I I I I I I I I I I 80 I I I I I I I I I I I I I I I I I I I I I I I I I I I �o I I I I I I I I i I I I I I i I I I I I I I I I I I I W so Z I I I I I I I I I I I I i � I I I I I I I I I I I I I I Z 50 W I i I I I I I I I I I I I I � I I I I I I I I I I I I I a ao I I I I I I I I I I I I I I I I I I I I I I I I I I 30 I I I I I I I I I I I I I I I I I I I I I I I I 20 I I I I I I I I I i I I I I I I I I I I I I I I I I �o I I I I I I I I I I I I I i I I I I I I I I I I I I I I 0 100 10 1 0.1 0.01 0.001 GRAIN SIZE- mm. %+3" %Gravel %Sand _ %Fines_ Coarse Fine Coarse Medium Fine Silt Clay 0 0.0 7.2 I 30.1 13.4 � 16.1 16.8 16.4 0 0.0 59 ' 13.2 12.5 24.1 � 2I.4 22.9 LL PL D D D D D D C C 0 13.6418 4.0436 2.1157 03276 0 7.4198 1.0964 0.5793 0.1825 Material Description USCS AASHTO ' o Silty Sand��vith gravel SM ❑ Silty Sand�vith some gravel SM Project No. T-6995 Client: Quadrant Homes Remarks: � 'Project: Copperwood Renton, Washington o Location: Test Pit TP-10 Depth: 2 feet ❑ Location: Test Pit TP-10 Depth: 6 feet Terra Associates, Inc. Kirkland WA Figure A-IS 6.2 Wetland Report by Soundview Consultants d ated J u ly 14, 2014 WETLAND, FISH AND WILDLIFE HABITAT ASSESSMENT REPORT COPPERWOOD RESIDENTIAL PLAT REVISED JULY 2014 ------------ - - --- -- �OLL12��TL�LlT �OYLIZL��CL12�� � Executive Summary Sound��ie«- Consultants LLC «-as hired b}- Bar�;hausen Consultin�; Engineers, Inc. and Quadrant Homes (Applicant) to delineate and assess ��-etlands, tish and v�-ildlife habitat, and/or other potentiall}--regulated aquatic features on an approsimatel�- 12.68-acre site located �vithin the Cit�� of Renton, �k%ashington. The subject propert}- consists of eight parcels (ILing Count�- Ta� Parcel \umbers 15230�9043, 1�23059066, 1523059067, 15230�9093, 1523059100, 1523059170, 1�230�9201, 1�23059221) located in the Northwest '/a of the Southeast '/a of Secrion 15, Township 23 North, Range OS East, ��'.l�I. The areas incorporated in this assessment include both the subject property and surrounding offsite areas located within appro�imately 11� feet of the subject propert��. The proposed project (Copperwood Residenual Plat) u-il1 provide 47 additional single-familj� residendal units, transportation impro�ements, and associated infrastructure �vithin the Cit}' of Renton. The subject property u�as investigated for the presence of potentially regulated �vetlands, drainages, tish and �cildlife habitat, and/or priorin� species on �1pri1 2, 2014 and re-inspected in June 2014. i�To potentially� regulated �vedands u-ere found onsite. One stream (liaple�vood Creek Tributar�- 0303) �vas identitled on the eastern side of the propern. The Cit�- of Renton identifies �iaplewood Creek Tributar�� 0303 as a Class 3 non-salmonid-bearing perennial stream. In the northern portion of the propem•, the stream is lo�v-gradient �vith gently-sloping banks; however, in the southern portion of thc property, the channel is located in a ravine with steeply sloped banks and several natural tish passage barriers. The ra��ne associated �vith the stream corridor contain both Sensitive and Protected slopes as classified b�• the Cin� of Renton. l�n artificiall}- constructed s��-ale u�th emergent ��-etland �-egetation u�as also found onsite draining into l�aple«�ood Creek Tributary' 0303. The s«rale i� documented to have been constructed in 1993 as a landscape and drainage feature and is not likelyr r��ulated b�� the City of Renton per Renton�funicipal Code Sections 4-11-230 and 4-3-050 L, nor is it Like1�- regulated b}- the �t'ashington State Department of Ecolo�� under RC��' 90.48 or 36.70A.030(21). Both of these features �tiere addressed in the original ��'edand, Fish and `�'ildlife Habitat Assessment Report prepared for the project dated �pril 21, 2014. Ho�vever, an independent electrofishing study, previousl�� undisclosed to Soundview Consultants LLC and the .�pplicant, identified fishes below a natural tish passage barrier in the southeast corner of the property� classifying this onsite stream reach as a Class 2 salmonid-bearing stream. Follo�ving disclosure ot the prior independent stud}-, a site �risit �vas conducted to verif}' the accurac� of this assessment. Sound�-ie�v Consultants LLC's supplemental site visit idenutied salmonids below an onsite natural fish passage barrier. Therefore, a small portion of�Iaplewood Creek Tributarv 0303 in the southeast corner of the site must be reclassified as a Class 2 salmon-bearing stream, and minor re��isions to the buffer management recommendations are necessarti- to address increased buffer reyuirements. The revised residential plat still includes 47 single-family residences, ne�v access roads, one storm�vater tract, e�:tensive open space tracts, and associated infrastructure, and direct impacts to the stream u-ill be entirely a�oided. In addition, proposed impacts to stream buffer are minimal and limited to placement of a treated storm�vater outfall, minor grading, a pen�ious �valking trail, buffer reductions, and buffer enhancement actions. Impacts to the buffer �vill be mitigated through buffer a�-era�in�;and non-compensator}-buffer enhancement actions. 118G.0(10� BCF.�Quadrant—Coppecuood Residenrial Plat Sound�-ie�r Consultancs LLC \l''edand,Fish and\V'ildlife 1 labicat Assessmcnt Rep�>tt 1 Re��ised�uh�l�,2014 Wetland Summa Table Approximate A Regulated Under Regulated Under Regulated Under Feature name Size Class Renton Municipal RCW 90.48 Clean Water Act onsite Code 4-3-050 Constructed Swale lu'If \1_1 No No Aot Likcl�� Tributary•0303B 1401f ? Yes Yes Yes Tributary 0303� 61�lE 3 Yes Yes Yes � Rcnron\funicipal Codc 4-3-OSO.I.. �'.1rca suuch of t7a<�AV�-]8 in thc southc-astcm corncr uf the sir�. `:Arca nunh��f:lag\V�-lti in thc n��rc�r:�[ern ihrce eu�.iners ut ch���Etc. 1 IRG.i�(xi� BCE/Quadrant—Coppenti•ood Residential Plat Sound�•iew Consultants L[.0 \\rcl:ind.[�ish and\\ildliFe f I:�Uirat:\�secsment Re��rt 11 Recised�ul� 14,Zfi14 Site Map q �� ,�0 340 � ; -- - - ; , T--.� - -�- -i- - �� �� - ��._'` I I I I '__`� - J 1 � I 1 I I � � ( � G.!}SS 3 STR�A�A ) I 2 STREAAI i�- .� i � (I�RTH OF 8) I (�-I OF WiS) �"+ ��------------ ;��=--L--1l-- �- �+-t= f a.r=� _� _ �, ''-, i , .---- — �--- �...� _; F^���������.r.���������������.����`���������". ��� �����/Y�'� � a� �� �—.-� ___ la7pi9[ - _ � P !�<S 1. �-� �- - r " ,:` - �•�'�'ii'; ; �- -- - s �-`•r: �. .{'_ i- I � � r� ` # �. �� �-`� ' I� // - F � .. ��.��,' � � - - . - - l � _ ~(, ____ _ � - j'i _ e'� i � ': `J f�� ' - �. � i � _' - ` � � � � f' � --. . � i 1 _� ,�' � �_ __ _ � t , ,, ; �, � S �,_ �` : r� -- - ' ' � �' - \ ;� � � � -''" �- Ml1PLE WOOD TRIB�JTARY 03Q3 I � ,; �:' �L---"-� _ __ (CLASS3) _' ' �G �. C — ' .-; % —��� I �I �`� / � . _. ' -- r^' � i'- � ��i�� % -�f :' - . .-r'I M1� _ ��-y y�I ::T �r � '--� ,,y p ! ! _ r. - - . �� ' - ��+s�_�.'_ ��.J 'i � �,'--- ----,-� � I .� � �' � '-� 'f �! j r`- - --- '---`-� f' !� �1 ' ( Yr� —' ',�� � r~�J�' 1" �I � �� I � � 'l �;� ��1' �: ;' _ '�`�� � ,� — cor�s�ucr�swat�_ _ - ; ` I _� �'�` -_--�_—'__tCi.A.Ss 5} �- �� ' , J r k--' � � - - _ •_ - : L '. y � f�' � ' �� � � j - .•� _ r �� i � j " � � � . �_ r i - "i , � ,� - ! i � _ t � � ' � 1� � ' - _- _ �' ��4 � �'�. E7it�TING dRAtNAGE T f � �r- �� ; �, �H��? , _ � i, yY4 �_� - I�•- �, � ` � ' � � i ; '- - -- �- _ -r- -- � 5 � .1�� �. � '�� r-, � ` ��-'- -- -- i I ' ��� —_ � � -� � � �� i � � � ' ��. j� L��,� 3 j `G..� r„I—�s,r., , -_ � '� i = �� :2: ��r„v:�-s �.�. "�c� f � -- : �' f i EXISIING STRIJ�CTURES, • ��, +.y±-a' - � ,I (TyPICAL} , , •, t i� p �L' I �,. , � . 4 \� r� \�� `�l ; s � .`i' `ti \ —�` `� ,' �•`.,�'� ,� r' �t � . ',i � � _. _�,����. ! �i �I.' ��� � . �'' � f- ��`� %} � � - ' � :•-.. _ , t� i � � ' - - _ _ — 5 , , . � I b-- 118G.0005 BCE/Quadrant-Copperwood Residential Plat Soundc�ew Consultants LLC \�'edand,Fish and\C'ildlife Habitat Assessment Reporc lii Re��sed July 14,2014 Table of Contents Chapter1. Introduction...................................................................................................................................1 Chapter2. Proposed Project...........................................................................................................................2 2.1 Project Location......................................................................................................................................2 2.2 Project Description............................. .................................................................................................... Chapter3. �iethods..........................................................................................................................................4 Chapter4. Background....................................................................................................................................6 4.2 Topograph5�and Drainage Basin..........................................................................................................6 4.3 Local and National t�%etland In�entories.............................................................................................6 4.4 Vegetation............................................................................................................ ........6 ............................ 4.5 Soils...........................................................................................................................................................6 4.6 Prioritt-Habitats and Species.................................................................................................................6 4.7 Precipitation.............................................................................................................................................7 4.8 Prior Electrotishing Sunney...................................................................................................................7 Chapter5. Results.............................................................................................................................................8 �.1 Drainages..................................................................................................................................................8 Chapter 6. Regulaton-Considerations.........................................................................................................11 6.1 Local and State Re9uirements.............................................................................................................11 6.2 Federal Regulatory Considerations.....................................................................................................12 Chapter 7. Buffer Averaging and Enhancement Plan...............................................................................1� 7.1 Purpose and Need.................................................................................................................................1� 7.2 Description of Impacts........................................................................................................................15 7.3 i�Iitigation Approach and Best l�Ianagement Practices ...................................................................16 7.4 Buffer Averaging Efforts.....................................................................................................................17 7.5 Enhancement Actions..........................................................................................................................17 7.6 ��irigation Goals, Objecrives,and Pertormance Standards............................................................18 7.7 Plant 1�laterials and Installation...........................................................................................................18 7.8 �iaintenance &i�lonitoring.................................................................................................................20 7.9 Reporting..................................................................................................................... .............21 .............. ?.10 Contingenc}� Plans........................................................................................ .......21 ............................... ?.11 Early Closeout.....................................................................................................................................21 Chapter8. Closure..........................................................................................................................................22 Chapter9. Report Summary..........................................................................................................................23 Chapter9. References....................................................................................................................................24 Figures Fi�urc l, Vicinit}� :�Iap..................... .....2 ............................................................................................ 1 1 SG.0pp5 BCE/Quadrant-Coppeiu�ood Residential Plat Sound�ieu�Consultants LLC I \V�rdand,Pish and\C�ildlifr I labirat Asses�menr Report Iv Re�-ised�uh•14,2014 Tables Tablc 1. Precipitation Summar}.........................................................................................................7 Table 2. Drainage Summar��–Constructed Swale.............................................................................9 Table 3. Drainage Summarti�–lfaplewood Creek Tributar��............................................................10 Appendices ,-�ppendil _�—ltetl�ods and Tools .�ppendix B —Background Information �-�ppendix C—Plant Species List .�lppendix D—Site l�faps and Plan Sheets 1-�ppendit E — Biologist Qualifications 113G.1�Op5 BCF/Quadra�t—Cuppenx�ood Residential Plat Soundaiew Consultants LLC \\edand,Pish and\\'ildlife I labitac:lssessmenc Repott v Recised�ul�•14,2074 Chapter 1. Introduction Sound�-ie�v Consultants LLC ��-as hired b<< Barghausen Consulting Engineers, Inc. and Quadrant Homes (r'�pplicant) to delineate and assess «Tedands, fish and wildlife habitat, and other potentiall�•- regulated aquatic features u-ithin or adjacent to the proposed Copperwood Residential Plat. The proposed project is located at�001 Southeast 2"`' Place �vithin the City'of Renton,�k'ashington. The subject propert�- is situated in the North�vest '/a of the Southeast 1/a of Section 15, Tournship 23 , North, Range 05 East, `�-.�i. (King Counn� TaY Parcel Numbers 1523059043, 1523059066, ' 1523059067, 1523059093, 1�230�9100, 1�230�917�, 1523059201,and 1523059221). The subject propert}-and surrounding areas �vithin 11� feet of the subject propern-«-ere in�-cstibated for the presence of potentiall�- regulated «-etlands, streams, fish and �rildlife habitat, and/or priorih� species in April of 2014 and re-inspected in June of 2014. �n additional supplementar�' site visit�vas � conducted follo�ving disclosure of an old electrotishing sur��ey (Cedarock Consultants, Inc., 2006) previously unknown to Soundvie�v Consultants LLC and the r�pplicant. The site investigations idenufied one regulated stream and one non-regulated, artificiall�� constructed swale. The stream is referred to as i�iaplewood Creek Tributary 0303 b}' the City�of Renton. No impacts are proposed to the stream, and on1�- minor impacts are proposed to the stream buffer, ��-hich �vill be addressed b�- buffer averagin� and enllancement actions. The purpose ot this ��-�tland and tish and ��-ildlife habitat assessment is to identin- and asse:ss the presence of �vetlands, tish and «�Idlife habitat, and/or priorit�- species on or near the subject propert�' and to identif�� management recommendations for the proposed project. This report includes conclusions and recommendauons regarding: '� • Site description,project description, and area of assessment; � Background research and identification �f potentiall�� regulared critical areas in the �-icinit�� of the proposed project; � Identification,delineation, and assessment of regulated wetlands and water bodies; • Identification and assessment of fish and wildlife habitat and/or priorit5- species locat�d on or near the subject property; , • Standard buffer recommendarions,building setbacks, and development limitations; • Proposed buffer reductions and temporar�-impacts; , • Existing site maps detailing identified critical areas, standard buffers, proposed butfer modifications, and non-compensator�� mitigation acuons, and • Long rerm habitat management recommendations and impact minimization measures. 1156.000� I3CE/Quadranc—Coppernood Residential Plac Suund�ie�� Consultants I.L(; �C'edand,fish and\\ildlife Habirat.\ssessment Report 1 Reciscd�ul� l�l,?i�14 Chapter 2. Proposed Project 2.1 Project Location The subject property is located in the City of Renton near the eastern boundary of the ciry limits. The subject property is situated in the Northwest '/a of the Southeast '/a of Section 15, Township 23 North, Range OS East, VZ'.I�i. and comprises eight parcels (King Count�� Tax Parcel Numbers 1523059043, 1523059066, 1523059067, 1523059093, 1523059100, 1�23059170, 1523059201, and 1523059221). A King Count}�tax parcel map of the subject property is presented in c�ppendix B. To access the subject property from the Tukwila area, via lnterstate 405 northbound, take Etit 4 to�vard Washington-900/Bronson W'ay.Turn right onto ��'ashington-169 north. After approximately 360 feet, take the first right onto Sunset Boulevard North. After 0.2 mile, take the first right onto Northeast 3`d Street. Proceed 0.9 mile and continue onto Northeast 4`� Street. Proceed 1.0 mile and turn right onto Duvall Avenue Northeast. After 0.5 mile, Duvall Avenue Northeast turns slightly� to the left and becomes Southeast 2"d Place. 'The subject property will be located on the right side of Southeast 2°d Place after approximately 0.2 mile. Figure 1. Vicinity Map. NE��h 51 NE 4th St NE 4th St NE 4th St NE Slh S� NE Lt. lesSchwab Un�udSutes - - -. , ,:.� ; r.�;�:.�: es .:�a �i T��PCMIPf a � vOStO�(1C! - - - _ _ 'AE=..',1' _ .•,.�_�t p _ .--:�_. nel�wa � � '� ^ �.� tiEJrdSt v `e'+ • � c} z Herirage T NE.'M% 3 _ HE IM P: �ih'2rid�t � Perk .y n m tiE�nd4 �' .z„ NE?�CSI � - _ � 2 �'EZry� SF13Ir:��;l m n � � b� ` .. -� NClstq r�`� NFts7p 3 �. ' % � o = SLI'.?;d5t o kE!uh � z a > � . ... ���5� NE 1 ct St x T �Z` 3 � SEtnF� �Etc�St SCI:tPI O _:?ryepnD� �A��eh SESn051 Sp:�Sf St?^,:51 SE 2nt1 Ct SF2ntlPl � SFin9C1 = � �S EEt3G�n5t SE7nd�'I r-�.�r�_ct�� � SE,��St � � - n.scnoodDr � sp� � K :♦�� 'SE)37�nSt 5�3t MdDt¢wood � `t _ Perk m �.�r c Ss� � � �E SE�V+� _ L ,�a� ' =tt.E�;P. ;E138Mv1:E ,L _ ''n, p; SE 139!h�I = '(;, SE 139th FM- s Subject Propert�- : ; � > > � � _ > - � •a;stn 4F�fl F % =' o `n � m � n '�S+ ,,. S�", 3 3 y -, _ 5(142�d$1 � - - ro R , � ` 5E t_2nd St �$f 1<2ndS� �, \ - '> .-E� ' g > s 3 3 3 �A,meP .r+u_ ; T � T 3 � c�f' ��' -..r ;,, r- T� Sf I43idi`I 9 �, �+ � � - � - ., ����on v' °i o r. Sf t t5ry �M���"�aiie ' $� � ��� � � ��% 3 -�9d �r4Sinc� �"� ,'�, '.. .� t5a , MapllwooA �" `P�" �oaoh �3 ' � cdreo„�u " � �a� :� Source:Google Dfaps ]18G.0005 BCE/Quadrant-Copperw�ood Residential Plat Soundedew Consulcants LLC ��'etland,Fish and u'ildlife Habitat Assessment Report 2 Ret�sed)ul�14,2014 ' li � 2.2 Project Description ' The �pplicant proposes a single-famil�� residenrial de�-elopment�ti-ithin the appro�:imatel�� 12.68-acre subject property. The proposed project includes demolition of all but one of the e�isting residences, removal of scrap and debris associated with the previous residential land use, clearing and grading for construcrion of approximatel� 47 residential housing units u-ith dri�-e��ra��s, parking areas, associated utilities and infrastructure, and buffer reduction, averaging, and enhancement acrions. I The proposed project«-ill also provide fully engineered stormwater tacilities to the Cit�� of Renton's , standards. The south�L est faciliaes will require placement of a storm�=ater outfall and pervious «alking trail along «ith minor grading actions ��ithin the stream buffer and minor buffer reducrion �-ia buffer averaging in the southeast corner of the site. �nST impacts associated �vith the installation of this outfall, lo�v-impact trail, minor grading, and buffer averaging u-ill be mirigated for through non-compensator}� enhancement actions. For further details, z�ppendis C pro��des a site plan of the proposed project and mitigation dctails. 1]8G.0005 [3CE/Quadranr—Copperu•oodResidentiall'lat Sound�iewConsultantsLLC \t'etland,Pish and\C ildlife Habitat.lssessment Repott 3 Recised Jul� 1�,�014 Chapter 3. Methods The methods used to compl�- �vith Federal, State, and local assessment requirements are detailed belo�v. Please see Appendis r1 for further details of inethods and tools used to prepare the report. ��'etlands, streams, and other potentiall}� regulated fish and u7ldlife habitat �vithin the subject propert5- and offsite areas �vithin 115 feet of the subject property ��'ere incestigated, and potentiallj re�nilated critical areas �vere delineated and assessed by qualified Soundview Consultants LLC staff on �1pri1 2, 2014. A follo`v up site inspection �ras also conducted by Soundview Consultant's Principal Scienrist on �1pri1 3, 2014 to eerify� staff tindings. Publicl}' available background data was queried for documented wedands, streams, and/or fish and wildlife habitat on or near the site, including the U.S. Geographic Sun-e�- (USGS) topographic map, the Natural Resources Consen-auon Service (IVRCS) Soil Sunrey, National ��'edands Inventory (�1`�%'�, US Fish and ��-ildlife Service (L'SF��'S), ILing Count}- GIS data (il�Iap), Ciry of Renton GIS data, local precipitation data (NOAA), and various orthophotographic resources. Graphics and maps detailing background data such as site topograph}�, soils, vegetative buffers, basin area, and critical areas inventories are provided in rlppendil B. Potenual �-edand boundaries ��-ere determined using the routine approach described in the U.S. .�rm�r Corps of Engineers' (L;S��CE) ��'etlands Delineation i�Ianual (LTSr,CE, 1987) as moditied by the Regional Supplement to the Corps of Engineers �Y•'etland Delineation l�ianual: �x'estern �Iountains, Valle}�s, and Coast Region (Version 2.0) (USACE, 2010). 14lethods described in the ��"ashington State`�G'etland Identitication and Delineation:�lanual�vere not used since this document has been retired b}' the��G'ashington State Department of Ecology (Ecology) in favor of the updated CS.�CE methods. Ordinar�' High �!�'ater (OH���� determinations were determined using Ecolog��'s mcthod as detailed in determining the Ordinar4 High ��'ater lfark on Streams in �x'ashington State (Olson, 2008); definitions provided in RC��' 7?.55.011 (11} and ��'�C 220.110.020 (69); and US�10E's Regulaton� Guidance Letter\�o. 05-0� Ordinary High��'ater 1�1ark Identification (USACE 2005). Potential �vetland, stream, and drainage boundaries and storm�vater teatures �vere inspected, delineated, and surve�-ed over several dates in .�pril 2014. The field assessment �-as performed by Jim Carsner, Professional ��'etland Scientist;Jerem`� Do�vns, Principal Scientist and Environmental Planner; and Hannah Blackstock, Staff Scientist. To mark the boundary bet�veen potential wetlands and uplands, orange survey�or's tlagging �vas alpha-numerically labeled and tied to t-egetation or �vood lath along the wedand boundan-. To mark the points where data was collected, pink surve}-or's tlagging �vas alpha-numerically� labeled and ried at each sampling location. To mark the boundaries of streams and drainages, blue sun ey-or's flagging u�as alpha-numericall��labeled and tied to vegetation or striped flagging from prior assessments �cas verified. The location of each stream and drainage boundary� flag and data plot was surve}�ed by Barghausen Consulting Engineers, Inc. , The locations and features of identified features are described in Chapter 5, and sho�vn on plan sheets in ��ppendil C. I Follo�ving disclosure of a previoush unknown inclependent electrotishing surve�� performed on � i�laplewood Creek Tributary 0303 (Cedarock Consultants, Inc., 2006), t�;-o qualitied Soundvie�r � Consultants LLC Staff Scientists �rerified the location of the idenrified natural fish passage barriers 1 1)6.000� BCI:/Quadrant—Copperwood Residential Plat �ound�ie�r Consultants f.L,C 1V'etl�and,Fish and\�'ildliEc Habit�c:lcsessment Report 1 Re��ised Julc 14,31�14 on Jul�- 1, 2014. The onsite stream channel natural tish passage barriers �rere identitied usin� methodologies described in Fi.rh Pa.rsage Bar77err and Sairface Ik%'ater DiL�erriora Screening A.rses.rvnent an�l Przorzti�atiota ���a�7ual (WDF��', 2009). Natural fish passage barrier locations tivere marked using blue sun e�-ors fla��ing tape that was numericall}'labeled and tied to each located barrier. 1156.00(i5 I�CE;`Quadrant—Coppenaood Residenrial Plat Soundeicw Consultants LLC \C etland,Fi�h and\t'ildlife Habitat Assessment Report 5 Re�-ised�uh 14,?014 WETLAND, FISH AND WILDLIFE HABITAT ASSESSMENT REPORT COPPERWOOD RESIDENTIAL PLAT REviSED JULY 14,2014 PROJECT LOCATION 5001 SOUTH�ST 2"°Pr�CE RE�TON,WASHINGTON 98059 PREPARED FOR BARGHAUSEN CONSULTING ENGINEERS,INC. 1821� 72ND r'�VENL'E SOUTH KENT,WASHI\GTO\ 980�2 QUADRANT HOMES 14725 SE 36"'S'rx�:�:�',SL iT�. 100 B�.1_I.E.vt��:,��':�sHrnGTo�98006 PREPARED BY SOUNDVIEW CONSULTANTS LLC 2907 H�xBoxviEw DiuvE GIG H�IRBOR,��'.�Sxi:�GTot� 98335 (253) 514-89�2 `Soundv��� �'on�u�'tant� . Chapter 4. Background 4.2 Topography and Drainage Basin The surt-e}�ed topography of the site shou-s the landform as generall�� tlat with a slight rise in the ��-esternmost portion of the site and generall}� sloping toward the stream in the east. The banks of the stream are shallow with lo�v-gradient banks in the north but transitions into a steep ravine as it nears the southern property boundar�-. A King Countt- Topographic map is provided in ; Appendix B 1. , 4.3 Local and National Wetland Inventories The U.S. Fish and `�'ildlife Service's (USF��'S) National `�'edands Im-entor�- (N��'I) map does not � , identify any� wedands or streams on or near the subject properri-. The Cit�- of Renton s GIS maps also do not identifj-�vedands on or near the subject property=; ho�cever, the Cin�identifies the stream as a Class 3 u-aterbody on the subject propern-. Prior to the stream entering the subject propern- to the north, it is identified as Class 4 water. The N��'T and City of Renton maps are provided in Appendix B2 and B3, respectivel}-. 4.4 Vegetation The majority� of the propern' is cleared and developed «-ith single-family residences. i�Iost of the �-egetated areas are dominated b}�landscaped areas and mo��red lawn. The area containing the stream corridor (I�ing County Parcel Number 1�2305906?) is the onl}- undeveloped portion of the subject propertS�. 4.5 Soils The NRCS Soil Sunrey of ILing Countt- idenutied one soil series, Alderwood gra�-e11�� sandtir loam, 6 to 1� percent slopes, on the subject property. A soil map is provided in Appendiz B4. rllden�ood (AgC) series soils are considered non-h�-dric e�cept for inclusions of Bellingham, \orma, Tuk�vila, and Shalcar that are associated with small depressions. Alderwood soils are described as moderately a;ell drained soils on undulating to hilly landforms that have a dense, tirer�r slo«�ly permeable glacial till at a depth of 20 to 40 inches. A typical pedon of the rllderwood (r�gC) series is: 0 inch to 2 inches of a �-ery� dark brown gra�-ell}r sandy loam (10YR 2/2); 2 inches to 12 inches of a dark bro�vn gravelly sand�r loam (10YR 4/3); 12 inches to 27 inches of a gra�-ish-brown gravelly sandy loam (2.5Y 5/2) with light olive bro«n mottles (2.5Y 5/6); and 27 inches to 60 inches of a gra�rish-bro��rn till (2.5Y 5/2) with light oli�-e brown mottles (2.5Y �/6) and �vith light olive bro��-n mottles (2.5Y 5/6). 4.6 Priority Habitats and Species t`'ashington Department of Fish and ��'ildlife's (`�-'DF'���� Prioritt� Habitats and Species (I'HS) maps and data identif�� a Biodiversity� l�rea and Corridor (Cedar Ri��er Valle}- Open Space l�reas) onsite, primaril�� located in the riparian corridor associated ��-ith the stream. ��%DFtiY''s interactive data map (Salmonscape) identities no streams «�ith fish presence «�ithin 300 feet of the subject propert��. No �� I 1 S6.00�C» BCG/Quadcant—Copper��ood Residenrial Plat �ound�ie�c Consultan[s LLC I \F'etl�nd,Fish and\�'ildlife Habitat.\ssessment Report 6 Re�ised Julr l4,?Ol$ priority habitats or Threatened, Endangered, or Sensitive plant or animal species were identified during this investigation. The PHS and SalmonScape maps are provided in Appendix B5 and B6, respectivel`. 4.7 Precipitation Precipitation data was obtained from the �lauonal Oceanic and Atmospheric Administrarion (NOt�) ureather station at SeaTac rlirport in order to obtain percent of normal precipitation during and preceding the investigation. A summar��of data collected is provided in Table 1. Table 1. Precipitation Summary' Date Day of Day Before 1 Week 2 Weeks Month To Water %of Prior Prior Datez Year3 Normal� .4/2/14 0.00 0.00 1.57 1.75 0 26.25 92°/a ' Data obtained from V0.�1A weathet station at SeaTac.liiport. (crr�:'i u��u��reather.�>r,�/clim ite inde�.�hn=��f_��=����i). 2 Precipitadon for the month is the same as for the Year-m-Dace. ' \Y'ater Yeaz is precipitation from Ocrober 1,2013. ° Percent of nonnal is sho�tm as for the dap/for the}'ear. The precipitarion data indicates appro�imatel}' 1.75 inches of precipitation fell ���ithin the t�co weeks prior to the last visit and precipitation was nearly normal (92 percent of normal) for the �vater year. However, these metrics do not retlect the e�tremely� high rainfall encountered during l�Tarch 2014, �vhich was 9.44 inches and 253% above normal. In fact, March of 2014 was the wettest I�Zarch on record for the SeaTac record, surpassing the old record of 8.40 inches (National ��'eather Service, 2014). The precipitation data suggests that daily rain events mat�have caused areas not normall}-u-et to become saturated and/or inundated at the time of the site im�esrigation, and such condirions «•ere considered in making professional ��-etland boundarv determinations. 4.8 Prior Electrofishing Survey A previous electrofishing survey u-as conducted by Cedarock Consultants, Inc. in 2006. This surve�- documented fish presence in the East Fork of 1��laplewood Creek, which corresponds to the onsite 1�laplewood Creek Tributar�r 0303 herein. However, this prior assessment also identified a natural fish passage barrier in the southeastern portion of the project site. Two adult cutthroat trout and si� fry were documented during this electrofishing survey� just belo�v the plateau that creates the lowermost natural fish passage barrier. Cedarock Consultants, Inc. recommended that the reach downstream of the natural fish passage barrier be classified as a Class 2 stream and the upstream reach be classified as a Class 3 stream per RI�iC Section 4-3-050 L.5. A map provided in this prior surve�� report is included in r'ippendis B7. 118G.1)00� BCE/Quadrant—Coppen��ood Residential Plat Sound�-iew Consultants L.L.0 \l'edand,f=ish and\t'ildlife Habitat:lssescment Report 7 Recised�ul}�14,2014 Chapter 5. Results 5.1 Drainages The site investigation identitied tt�-o aquatic features onsite, including one regulated stream (ti�aple�vood Creek Tributary 0303) and one non-regulated, artificiall}� constructed s�vale. Zfaple�-ood Creek Tributar�- 0303 runs north to south in the easternmost parcel on the subject propert�- (ILing Countt� Parcel Number 152305906?). The constructed s��-ale runs �vest to east and drains to the stream. 5.1.1 Constructed S��vale The arriticially constructed s�i�ale originates trom a series of curtain drains and catch basins draining adjacent areas and containing multiple single-family residences and discharges to an outfall located abo�re �iaplewood Creek Tributan- 0303. The constructed swale e�hibited some �cedand characteristics, including hydrophyric vegetation (reed canarygrass) due to lack of regular maintenance on the drainage channel; however, the s��rale is documented as an artificial drainage feature constructed in 1993 as a landscape and drainage feature as part of a storm«ater and ground�vater management plan for the site. Therefore, the swale does not meet u-etland criteria as defined b}- Renton l�Iunicipal Code (R:'�TC) 4-11-230 and 4-3-050 �f and should not be re�ulared as a �vetland feature or stream. The feature also does not meet RC��'90.48 or 36.70r1.030(21) criteria for regulation as a wetland or stream by the State of��'ashin�ton. The artificiall�� constructed s�vale is documented to be of anthropogenic origin «:here no naturall�� derived channel had previousl�- e�isted, is kno��n to collect and convet- surface �vater and/or groundwater from adjacent developed areas, and is non-fish bearing; therefore, the swale meets the criteria of a non-regulated, Class � �vaterbod�� under R1ZiC 4-3-0�0 L.1.a.v. Class � v�-aterbodies are e�empt from all regulations under Rl'�ZC 4-3-050 L. The outfall for this constructed swale would be treated similarl�T; however, the outfall is located in the buffer far l�iaplewood Creek Tributar�- 0303. This outfall can be removed as part of the buffer enhancement plan detailed in Chapter %.of this report. �� summar�- of the constructed s�vale is pro�-ided in Table 2 belo«-: � ll8G.W0� BCEi Quadrant—Copperuuod Residencial Plat Soundcie�v Consulcan�s LL(; I AV'etland,Fi�<h and\�'ilcllife Habieat-Assessment Reputt S Reci>ed Iiilti 1�,?i�l} Table 2. Drainage Summary—Constructed Swale. DRAINAGE INFORMATION SUMMARY ', � \t ' ,'. ���K:; Feature Name Constructed Swale ' � � ' ' �'� ��, ' „? � WRIA 8 �3� � � ��'�"`��,Y WA Stream Catalog# N/A , '`�"� ' �, ' Local Jurisdicrion City of Renton �^ ' �"• �'�'���� DNR Stream Type N/A � �. r � .x� �: f�+�.i .& :..: ; ,.,, :., �t'= �� . �,� '' i�,;. . Local Stream Rating Class 5,non-regulated � ��' �"`-a�f', ��r :;�.� � � f..�.�:! Buffer Width N/A �'�•�- l i, �t� ��w.� s��� $x:ti�Y�- Documented Fish Use N/A Location of Feature The swale is located on Parcel Number 1523059201 , The swale runs west to east, with water sourced from curtain ' Connectivity(where stormwater drains and catch basins in adjacent areas to the west. "The swale drainage feature flows from/to) ends at an unmaintained outfall in the buffer of Maplewood Creek Tributarv 0303. Riparian/Buffer Condirion Class 5 �raterbodies are eYempt from regulaaon, and no buffer is re uired. 5.1.2 Maplewood Creek Tributary 0303 The onsite tributary� to �laplewood Creek (0303) originates offsite in de��eloped residential areas to the northeast and northwest of the subject property and discharges onto the subject property through a culvert under SE 2"d Place. biaplewood Creek Tributar57 0303 flows southerly across the property in a broad, low-flow channel with a low-gradient riparian corridor in the north with increasingly steep slopes adjacent to the channel as it enters a ravine and approaches the southern boundar}�. The stream leaves the subject propert}' and turns west to enter l�faple�vood Creek, approximately 2,000 feet to the south and west of the property. Observed flo�vs indicated that the ' onsite poruon of the tributary is likely perennial; however, precipitarion for :�larch �vas above normal, and there is a possibility that the stream may be seasonal. North of the culvert under SE 2"d Place, the 14iaplewood Creek Tributartrn 0303 is idenrified as a Class 4 waterbody by the City of Renton; however, once the stream enters the property from the north, the Ciry of Renton identifies the tributary as a Class 3 waterbody. A report disclosed to Soundview Consultants LLC and the Applicant by the City of Renton in June of 2014 identifies a small onsite section of i4Taplewood Creek Tributary 0303 as a Class 2 wwaterbody�vith the rest of the onsite stream being Class 3. r� clear and distinct natural fish passage barrier is located just upstream of where salmonid fry and cutthroat trout were detected b}�Cedarock Consultants, Inc. in 2006. This Class 2 designation in the lowermost reach of the stream �-as confirmed b}' Soundvie��� Consultants LLC Staff Scientists on July 1, 2014. The steep gradients and several natural fish passage barriers �vithin the onsite stream reach betz�-een the Class 2 and Class 3 waters, including subsurface flows and a 10-foot vertical drop, indicate that salmonids do not and cannot migrate up the tributary and are not likely present upstream of�vhere salmonids��vere detected. ll 8G.0005 BCE/Quadrant—Coppecwood Residendal Plat �e�und�ieu Consultanrs LI.0 �Y'etland,Fish and�k%ildlife Habitat Assessment Report 9 Re�ised�ul}�14,201�} Table 3. Draina e Summa —Ma le�vood Creek Tributa . DRAINAGE INFORMATION SUMMARY '�� ` Feature Name ;�Iaple�c�ood Creek Tributar5- (0303) ',' '�� i i ` .W RIA 8 •R . . . t +��� 'i n; '" i .' p ,t �� '�.� �i,� � � � t; � ��/A Stream Catalog# 0303 +��� ; � ' . rE!� ��_ ..`}� � t' � � ,l ��;.�•���{ Local Jurisdiction Citv of Renton � �? ,;�� '� :,:,<A,�„ _ � "��k� �`,;R,��'� a�,.�., �`;��s ".!��r� ,{DNR Stream Type N/A �+�4, ' � ��,_+ , �'i � '. "�`�; � s d�"�i ' :Local Stream Rating Class 2 Lower Reach (below W-18) � 1 . � Class 3 U er Reach above W-18 �.�a�. .� ,:-�, : � � Buffer Width 100 feet Lower Reach ; j� � � �,,i 75 feet U er Reach . ��. �� � � - Documented Fish Use Fish obser�red in downstream �•;,t� . •'}� � ortion of onsite reach stream 'I-hc ��n�itc segment of the tributarv is appro�cimately 755 feet (combined) Location of Feature �on tlo�vin north to south in the westernmost arcel. Connectivity(where The tributary drains residential and commercial properties to the north and stormwater drainage feature enters the property through a culvert under SE 2°a Place. It leaves the flows from/to) propert�in the southeast and enters I��fapleu-ood Creek appro�:imately 2,000 feet southwest of the ro e ,which eventuall�flows into the Cedar River. The buffer of the onsite segment of the tributary is modified but contains man}r native tree and shrub species. However, some portions of the buffer Riparian/Buffer Condition onsite are dominated by non-narive invasive species in some areas and contain manv iles of�-ard waste and other debris. 5.1.3 Stream Buffers Of the two drainage features, only l�laple�vood Creek Tributary 0303 is required to have a buffer under R1�IC 4-3-050 L.S.a.i.(b). The arrificially constructed drainage swale is identified as a Class � «-aterbod}r, as described above, and is not likely regulated b}� the Ciry of Renton or other State and Federal agencies; therefore, no buffer is required for this constructed feature. ��s a Class 2 and Class 3 stream, the Maplewood Creek Tributary�0303 requires a buffer width of 100 feet and 75 feet, respectivel}�. Onsite, the buffer consists of deciduous riparian forest with a canopy dominated b�r black cottonwood and red alder. Some areas of the understory include native shrubs, primarily salmonberr��, but many areas are dominated by Himala}-an blackberry and other non-native invasive species. Portions of the offsite buffer are modified with moderate to high densit�r development on adjacent properties to the east. In addition, a gravel drivewa�� and many piles of }-ard waste and debris are located in onsite areas of the western portion of the buffer associated with adjacent single-famil�� residences and maintained neighboring yards. �SUith buffer averaging and minor buffer enhancement and restoration measures, the modified Class 2 and 75-foot Class 3 buffers�vill be more than adequate to protect stream functions. 11 h6.0005 BCE/Quadrant—Coppeni�ood Residendal Plat Sound�-iew Consultancs LLC \t'edand,f ish and\\`ildGfe Habitat.lssessment Report 10 Re�-ised Julv 14,2014 Chapter 6. Regulatory Considerations � The proposed project is located in the Cin- of Renton. The site inaesrigation identified one �� regulated stream and one non-regulated s�vale on the propem-. No other potentially regulated , «-edands, streams, or other fish and wildlife habitat were identified on or �vithin 115 feet of the I subject propert�-. The buffer area of the onsite stream is some�vhat degraded in the north, being ' �-egetated by� Himala�-an blackberr�; and other invasive species and containing a substantial number ' of�-ard�zraste and debris piles and a gra�rel drive«rayr. Local, State,and Federal regulaton-implications ' are addressed belo��: 6.1 Local and State Requirements The constructed swale e�hibited some �vetland characterisrics, including hy�droph�tic vegetation (reed canarygrass) due to lack of regular maintenance on the drainage channel; ho«-ever, the swale is documented as an artiticial drainage feature constructed in 1993 as a landscape and drainage feature intended to be part of a storm�-ater and groundu�ater management plan for the site. Therefore, the s�z-ale does not meet ���etland criteria as detined b�� Renton �Zunicipal Code (Ri'�IC) 4-11-230 and 4-3-050 M and should not be regulated as a �vetland feature or stream. r1s the artificiall�� constructed s«-ale is documented to be of anthropogenic origin u�here no naturally derived channel had previousl�- eYisted, and as the swale is kno�vn to collect and con��ey surface �vater and/or �-oundwater from adjacent de�-eloped areas, the swale meets the criteria of a non-regulated, Class � «-aterbod�- under Ri�IC 4-3-050 L.1.a.v. Class 5 �-aterbodies are esempt from all regulations by� the Citv of Renton under R1ti1C 4-3-050 L. The feature also does not meet RC`�' 90,48 or 36.70A.030(21) criteria for regulation b}�the State of��'ashington as a���etland or stream. llapleu-ood Creek Tributar5, 0303 is identified on the northern onsite portion as a Class 3 ���aterbod}'. ��ccording to Rl�iC4-3-050 L 1.a.ui., Class 3 waterbodies are non-salmon-bearing perennial �vaters during �-ears of normal rainfall and require a 75-foot buffer. The do�vnstream, or southern, onsite portion of i�iaplewood Creek Tributary 0303 is identified as a Class 2 �vaterbody. �ccording to R1�iC 4-3-0�0 L 1.a.u, Class 2 �vaterbodies are salmon-bearing and perennial or inrermittent waterbodies. A Class 2 waterbod}- under RlliC 4-3-0�0 L.S.a.i.(a) requires a one hundred foot minimum buffer. The project is located a minimum of 75 feet from the Class 3 reach of the stream, but storm�vater infrastructure must be located closer than 100 feet to the Class 2 reach; therefore, minor buffer averaging is necessarti� adjacent to the Class 2 designated reach. In addition, placement of a peroious ��all:ing trail and treated storm�vater outfall are proposed «-ithin the Class 3 buffer, and some minor grading (approximatel� 3,000 square feet) is necessar�- in the modified Class 2 buffer. These addirional actions ��rill result in minor impacts, �vhich u7ll be offset «-ith natural �-egetation enhancement and restorarion actions within the stream butfer. ��ny activity> proposed �vithin the buffer must compl�� ��-ith the following standards as oudined in R1�iC 4-3-050 L.6: a) Preservation ofNative Vegetation:Existing natii�e vegetation.rhall be pre.ce�ved to tbe ex-terlt po.crible, preferaGly i9� cosuolidated area.r. l�) Revegetation Required.• IYlhere�vater Gody �u�er di.rturbance ha.r occu�7ed in accmzlance 2vith e.x-e��rptioia ar develop�rretrtpermet approval or•a�her�ctit�itie.r, reveget��ion lvzth ilatir�e vegetntion s/�a�l�e reqirirec% I 1 tiG.lK�O� BCE/Quadrant—Copperwood Residenrial Plat Soundeie�c Consul[ants LI.0 \C�ctland,Fish aad\�'ildlife Habicar.lssessment Report 11 Reci�ed(uk 14,2014 c) Use ofNative Species: I�hett ret�egetation is required, appr-oved�latia�e.rpecie.r, or otber approp�zcrte.rpe�ies �rattsrali�ed to the Puget Sortnd regiarz shr�ll l�e u.red. A varie�� of.�ecie.c shall Ge trsed lvhich serz�e as faod rr shelterfronz cli�f�atic etitretrre.r and predato�:r, afZd a.r strircture a9ar�coi�erfor reprod�rction and r-earzrtg ofj-orrjr;. d) Removal ofNoarious Species: IE�beri r•equir•ed a.r a cof�dztion of app�oval, rrrx�ror�s or�✓rld�sirnble spFrie.r r�f plasrt.r sl�nll l�e remoa�e�l or co�7trolled ro a.r to not conrpete lt�it/� native vegetation. e� Impervious Sr�rface Restrictions: [�'he�e imperviot�s sr�rfaces exist r�� bzrffer areas, ,rrrch i»�pe��rorrf sts�faces sh�ll not fie istcreaserl or e.x�anded u�itbitt tbe bz�er•area. Tbe e�tettt of Z171�781��ioars srrifaces u�itl�i:z tl�e Gr ffer area nray mzly be rear7anged zf t{�e reconfiguration of impen�ious.rrrrfaces nrzd r•e.rto��rfiotz of p�zor szsrfac��l area.r ispart of an enhaszce�nentpropo.ral t/�at improve.r ecologzcalfs�nctiosz of the areapaotected by the Gr�er: The buffer averaging and enhancement plan, as described in detail in Chapter 7, proposes remo�-a1 of non-native in�-asive species, yard �vaste piles, and the e�isting gravel dri�ewa}r and planting of all disturbed areas �vith native species in compliance with these requirements. In tact, the value and benefit of the buffer enhancement and restorarion actions proposed will greatl�r e�ceed the minor and temporary impacts associated ��rith placement of the walking trail, storm outfall, and minor grading near the storm pond. No impen ious surface currently esists or is proposed «-ithin in the buffer area. In addition, buffer averaging �vill result in no net loss of stream buffer e::tent or functionality (see site plans in r�ppendis C). tllong u-ith providing enhancement and restoration actions, the project must meet the additional criteria for permit approval described in R�'�1C 4-3-050 L.?.a and b, «�hich require that (a) as a condition of an�= approval for an�- development permit issued, a native growth protecuon area must be created containing the stream area and associated buffer and (b) the action must result in no net loss of regulated area or ecological function in the drainage area. The native gro�vth protection area �vill be established using a separate tract«�ith deed restriction per R141C 4-3-050 E.4.c. option iu. The native gro«-th protection area will encompass all areas of the site east of the final buffer line detailed on Sheet 3 ot Appendi� D. As stated pre�riousl�-, the benefits of the proposed enhancement and restoration actions far e�ceed the minor and temporary buffer impacts proposed by the project. In addition, a native gro�vth protection area will be created to protect the stream and buffer in perpetuin-. ��C'ith the enhancement actions proposed in Chapter 7 of this report, the nau�-e �ro��-th protection area�vill compl�- �vith the standards set forth in R��iC 4-3-050 E.4.b. d.2 Federal Regulatory Considerations The results of the 2014 site in�-estigation identifled one stream and one e�cavated drainage s�vale. liaplewood Creek Tributary- 0303 recei�-es ���ater trom natural and artiticial sources upstream of the site and has a documented direct surface ��-ater connection to �vaters of the U.S. known to be regulated under Section 404 of the Clean ��'ater Act (C�&'A). The drainage swale appears to have been originall�� constructed in upland soils for the purpose of conveying stormwater runoff from adjacent dri�e�ca�-s and residences and ground��ater from drainage sy�stems. The swale does not receive�vater from any sources potentiall}'regulated under Section 404 of the C��'A. In a December 2, 2008 memorandum from the Emrironmental Protection Agenc�� (EPr1) and USACE, joint guidance is pro`ided that describes waters that are to be regulated under section 404 of the C`�'A (USACE, 2008). This memorandum �vas amended on February 2, 2012 �vhere the EP�� and USACE issued a final guidance letter on waters protected byr the C`�'Ao ]186.0005 BCE/Quadrant—Copper��•ood Residenrial Plat Suund�ie«�Consultants LLC 1\'edand,Fish and\\'ildlife HabitaC.\sses�ment Report 1? Rc�ised luh 14,_'l)14 The 2012 guidance describes the following�vaters�vhere jurisdiction vvould be asserted: 1) traditional navigable �vaters, 2) interstate waters, 3) «-etlands adjacent to traditional na��igable waters, 4) non- navigable tributaries of traditional navigable �yaters that are relatively permanent meaning the�� contain�vater at least seasonall�- (e.g. tt�picall}' three months and does not include ephemeral�vaters), i and 5) �vedands that directl�� abut permanent waters. The regulated���aters are those associated with � naturall�r occurring waters and�-ater courses and not artificial waters (i.e. stormu-ater pond outfalls). liaplewood Creek Tributai-�- 0303 fits the description of Item 4 and is clearl�- re�ulated under Secrion 404 of the C`�'�1. 'I'he 2012 memorandum turther goes on to describe �vaters �vhere jurisdicaon would likelt� require further anal�-sis: 1) Tributaries to traditional navigable �vaters or interstate ��raters, 2) ��'edands adjacent to jurisdictional tributaries to traditional navigable�vaters or interstate �vaters, and 3) �X'aters that fall under the "other�vaters" category�of the regulations. In addition, the 2012 guidance identifies thirteen �z-aters or areas «�here jurisdiction ��-i11 not be asserted: 1) L�'et areas that are not tributaries or open ��aters and do not meet the agencies regulator}' definiuon of"wedands", 2) ��'aters escluded from coverage under the CV�'r'� b}' esisting regulations, 3) ��'aters that lack a "significant nelus: u�here one is required for a �vater to be jurisdictional, 4) Artificially irrigated areas that would revert to upland if the irrigation ceased, �) Arrificial lakes or ponds created byr escavating and/or diking dn� land to collect and retain u-ater and u-hich are used e�clusively for such purposes as stock �vatering, irrigation, settling basins, or rice gro��ring, 6) r�rtificial reflecring pools or s�-imming pools excavated in uplands, `� Small ornamental ��vaters � created b}- e�cavaring and/or diking dr�� land to retain ��ater for primaril�r aestheric reasons, and puddles, 8) ��'ater-filled depressions created incidental to construction activity, 9) Groundwater, including groundwater drained through subsurface drainage s}-stems, 10) Erosional features (gullies and rills), 11) Non-u�edand s���ales, 12) Ditches that are excavated wholl`� in uplands, drain on1�- uplands or non-jurisdictional waters, and have no more than ephemeral flou�, and 13) Ditches that do not contribute flow, either direcdS- or through other�vaterbodies, to a traditional navigable �vater, interstate «�ater, or territorial sea. The drainage s��-ale identitied on the subject propertv lacks a defined bed and bank and was clearl�� constructed from uplands as documented b}- the prior lando«-ner. The source of u-ater that ma�- be found �vithin this s��-ale is stormv�-ater associated �vith roadside runoff and a high ground��ater collection sy stem. The e�cavated s«�ale identified onsite appears to fit at least 3 of the criteria (Items 7, 9, and 12) for which the agencies are directed not to assert jurisdiction over, ho�i-ever, previous esperience �vith the Seattle Branch of the USACE's interpretation of the guidance indicates a�enc�- staff sometimes «rill tn- to assert jurisdiction over such features. Ho�vever, it is highl�- unlik�l}- such assertion of jurisdiction o�•er this s�t�ale is defensible gi�-cn the docum�ntation of the s��-ale. Should the USi10E decide to assert jurisdiction o��er tlie s��-ale under Secdon 40=� of the C�\-'.�, the project�vould still likel}- be covered under a simplitied CW�� Section 40� Nationwide Permit (N��'P) 29 for residential development projects as the limit of State and Federal permitting efforts under Secdons 401 and 404 of the C`�G'A. Final determination of N��%P coverage, though not likel}� necessary, is at the discrerion of the USr3CE, and other minor N��GP's, such as a N��-Z' 18, ma�� be also be used to authorize this project. 118G.0005 BCE/Quadrant—Coppenrood Residential Plat S��und�ie�r C�>n�ult:ints[.LC �Cedand,Fish and\t'ildlife Habitat:lssessment Report 13 Recisrd luh 14,?UI-t Federal permitting efforts �vould also trigger Section 7 revie�v under the Endangered Species Act (ESc,). The same permitting requirements �vould also trigger Secrion 106 re�-ie�v under the National Historic Presen ation rlct (\1HPA) due to the eltent of land-disturbing actions. As no Federal ; permitting is likelt� necessar}�, documentation for such additional revie�v requirements is not being ' prepared at this time and �vill not be prepared in the future unless USACE staff can justify a re�ulator�� netus «-ith the proposed project. 1 1 iiG.WO� BCE/Quadrant—Coppectcood Residcntial Plat Soundrie�c Consultants LLC \C'rtland,Fish and\V'ildlife Habitat Acsessment Rcpntt 1�3 Re�-ised Jul�-l4,�014 Chapter 7. Buffer Averaging and Enhancement Plan The follo�cing sections present the proposed buffer a�-eraging and enhancement plan �vith minor restoration actions to address the buffer impacts associated �vith the proposed project and satisf�� buffer width and native gro�vth protection area criteria. The proposed a�-eraging and enhancement acuons attempt to closel�- adhere to local Crirical �reas Regulations specified in R��IC 4-3-050 L.�.d and 4-3-0�0 E.4 and L.6-7, respectiveh-. The proposed buffer aeeraging and enhancement plan is provided in Appendi�:D. The buffer enhancement plan proposes to remove the Himala}-an blackberry and other non-native in�asive �-egetation b}� pro��ding a chemical application (pre-treatment) of the invasive plants prior to grubbing, u-hich would occur during the dn- season to minimize an� potential impact to �laplewood Creek Tributan- 0303 and its do�mstream tributaries. ��ddirional enhancement actions �vill include clean up and removal of the gravel drive�zTay and the significant number of�-ard waste and debris piles located within the buffer to midgate for the addirion of a pervious �valking trail along the perimeter of the buffer. This plan proposes enhancement efforts �vithin the stream buffer �vherever needed at the discretion of the responsible �vedand scientist and restoration actions wherever minor grading actions disturb the perimeter of the buffer such as stormwater outfall placement and installation ot the stormwater pond. No actions are proposed that w-ill intrude into or affect the stream channel. Please see Appendix D for planting specificarions and details. 7.1 Purpose and Need _ The purpose of the proposed project is to provide additional residential units and associated infrastructure within the Cit}- of Renton. The project proposes to develop a plat of fort}--seven (4� residential units �vith all necessar�� parking, drivewa�-s, utilities and associated infrastructure. A minimum 7�-foot protective buffer��rill be implemented to protect the regulated Class 3 stream and an averaged 100-foot buffer�vill be implemented to protect the Class 2 reach of the same stream. In � addition, only temporar}r impacts are proposed to onsite stream buffers through enhancement and restoration actions. The project seeks to mitigate for the minor temporaryr impacts associated uTith necessar`� placement of a treated storm«�ater outfall and grading in the onsite buffer area and provide compliance with narive gro�vth protection area requirements. 7.2 Description of Impacts No direct adverse impacts are proposed to ant� regulated critical area, as �Zaple��rood Creek Tributar�- I 0303 ���ill not be directl`�impacted by the proposed project. Ho���ever, the project proposes to place a «Talking trail, treated stormu-ater outfall, approlimatel}- 3,000 square feet of temporary grading «�ithin the stream buffer, resulting in minor temporary� impacts. Surface water and a portion of the roof�vater from the proposed residenrial plat will be directed to a detention pond which �vill treat and discharge stormwater into a dispersion trench which �vill direct the treared ��-ater to the stream buffer. In addition, vegetation enhancement and restoration actions «rithin the buffer urill result in temporary disturbance onlj�,�vith a resultant beneficial effect. The existing buffer onsite is degraded by the dominance of invasi�re Himalayan blackbern�, the presence of yard ��aste and debris piles, and the gravel drive�vay�. The dense blackbern- and �rard � waste piles keep emergent vegetation suppressed near the stream channel thus causin� increased 118G.W0� BCE/Quadrant—Copperu•oodResidenrialPlat ���und�ie�cCuncultinc.LLC �C�etland,Fish and n'i]dlife Habitatl�ssessment Report 15 Rccised�ulr 1 3,?u14 runoff and erosion to limit u-ater qualitt- functions within the buffer. The proposed project will substantiall� improve stream buffer functions including enhanced wildlife habitat and improvements to water qualit�� tunctions b� establishing a highl�� structured native plant communitc- and constructing a protecuve fence �vith signage to prevent continued disturbance of buffer areas. In addition, pedestrian access within the buffer�-i11 be contained b�- establishment of a lo�r-impact trail s�•stem to curtail trampling of nati��e vegetation and inappropriate uses �vithin the buffer. Other than the gra�-e1 areas proposed to be removed, no impervious surface currendy exists �vithin the buffer nor is proposed to be placed in the buffer b}� the proposed project. The proposed project does not propose to negativel}=impact offsite drainages nor will it be detrimental to an�other propertt�. Onlv a small portion of the stream buffer �vill be temporaril}r impacted during installation of penious �valking trail, outtall, and minor grading near the storm«�ater pond. The alignment of the outfall has been designed to avoid signiticant natice conifers, and temporary impacts will be limited to the smallest area necessar�- to allow installation located outside of OH��G'. Once installation of these items is complete, the disturbed areas will be finish graded and replanted �vith native vegetation. The extent of buffer enhancement and restoration actions proposed u-ill meet all native grourth protection area requirements and �vill greatly� etceed an�- miugation necessary for the minor and temporan�impacts associated with placement of the outfall. 7.3 Mitigativn Approach and Best Management Practices 'I'he proposed enhancement and restorarion plan is intended to provide an appropriate stream buffer functions «-ithout loss of area and non-compensaton� enhancement and restoration actions for an}- temporary impacts. The plan �vill also enhance the o�•erall buffer functionalit}r to meet native grou-th protection area requirements. Onsite buffer areas are dominated by� Himalayan blackberry� and contain significant numbers of yrard �vaste and debris piles. Proposed enhancement actions include treatment and removal of invasi�-e vegetation, removal of �-ard waste and debris piles, planting �vith native trees and shrubs, and establishment of an herbaceous understor`� to allotv the return of a forested canopti• and enhance water qualin� and habitat functions of I�taple�vood Creek Tributai�� 030�. Impacts to the stream are being full�- a�-oided, and impacts to the buffer are being minimi-r.ed '� through careful planning efforts and project design. Enhancement and restoration actions �vill occur cc�ncurrentl�- �vith the de�elopment of the plat. Temporar}- erosion and sediment control (TESC) measures will be implemented that consists of high-visibilit}r fencing (HVF) installed around native ��egetation within the buffer, silt fencing betu�een the graded areas and buffer, plastic sheeting on ' stockpiled materials, and seeding ot disturbed soils. These TESC measures should be installed prior to the start of development or enhancement actions and activel}� managed for the duration of the project. �1 concrete ��ash water collection basin should also be installed awati� from the buffer prior to cc�mmencement of construcuon activities requiring additional concrete work. All equipment staging and materials stockpiles should be kept out of the buffer, and the area �vill need to be kept free of s�ills and/or hazardous materials. All till material and road surfacing should be sourced from upland areas onsite or from approved suppliers, and u-ill need to be free of pollutants and hazardous materials. Construction materials along urith all construction �vaste and debris should be effectivel�- managed and stockpiled on paved surfaces and kept free of the remaining wedand and stream buffer area. Follo�ving completion of the residence, the entire site should be cleaned and detail �n�aded I I Sfi.000� dCF,/Quadrant—Copperu•ood Residendal Plat S�nind��ic�c C�mwltxnts I.LC \V�cdand,Fish and���ildlife Habitat,�ssessment Report 1G Rrciced �ulr I-1,?U1-1 using hand tools wherever necessan�, and TESC measures �vill need to be removed. In addiuon, permanent stormwater treatment features �vill need to be implemented as designed b�- the project en�;ineer. 7.4 Buffer Averaging Efforts :1s a result of thc re-classificarion of the southeast onsite reach of the stream from a Class 3 to a Class 2, buffer averaging efforts «�ill need to be made to accommodate the stormwater pond. ��'ith careful planning, buffer�vidth modification using the buffer averaging standards set forth in RI�fC 4- 3-050 L�.d may bc applied to this project if several criteria for appro�-a1 are follo�ti�ed; inclucling, buffer w-idth will not result in a net loss of ecological function, the total buffer area is no less than the required standard, and the buffer standard is based on best available science. The buffer averaging efforts for this project included an assessment of existing site conditions, critical areas and physical limitations, stream class designation, and anticipated project needs. The proposed buffer averaging efforts are very minor and attempt to strike a balance bet«=een these elements in a manner that allo�-s the best use of the site�vhile maintaining the integritt�of the eYisting critical areas. Careful planning and targeted implementarion of the buffer averaging exercise detailed on Sheet 2 ot .-�ppendix D, along v�-ith buffer enhancement actions, «�ll help ensure that no addiuonal negative impacts �vill be made to the critical areas identified in this assessment. Expansion of buffer areas surrounding sensitive areas and implementation of effecuve restoration and enhancement measures «-ill also help ensure that�-ater qualit�T and fish and wildlife habitat funcuons �vill be improved from its current state. 'The buffer reduction is only� proposed �vithin the outermost ertent of the onsite buffer where the stream uras re-classified as a Class 2�vaterbody. Increase in buffer area is proposed an adjacent area that is situated between the proposed residences and the stream. The proposed buffer averaging plan increases overall total buffer area on the site b}� 1,442 square feet (from c�isting 1,730 square feet to the proposed 3,172 square feet). z�s the proposed acuons u7ll increase o��erall buffer functionality, no net loss of buffer function or area is proposed. -` 7.5 Enhancement Actions Enhancement and restoration actions for the buffer include, but ma}'not be limited to, the following r�commendations: • Pre-treat invasive plants, such as En�lish iv}', Himala}'an blackberry, and Scotch broom, �ro�Uing in the tributary buffer u�ith a ��'ashington Department of Agriculture approved herbicide. After pre-treatment, grub to remove the in�-asive plants and replant all cleared areas with native trees, shrubs, and�round co�-ers listed in Appendis C; Pre-treatment of the invasive plants should occur a minimum of two weeks prior to removal; • Remove gravel associated with the etisting gravel driveway and break up the compacted soil «�ith a ripper attachment or tiller. Seed and plant disturbed areas; • On1�- native trees, shrubs, and groundcovers listed in Appendix C, or substitutes approved bc the responsible «etland scientist, �vill be used in disturbed areas to help retain soils, filter stormwater, and increase biodiversity of macroinvertebrates (i.e. insects); • ,-�n approved nati�,e seed mis will be used to seed the disturbed areas after plantin�trees and shrubs; ' 1 1 SG.0005 BCE/Quadrant—Cuppenrood Re�idendal Plat Suundcie�v Consultants LLC \V�edand,Fish and 1�'ildlife Hahitat Assessment Reporz 1' Re�ised)ulc 14,2014 • `,I . , �i , , � more frequentl5- if necessai-�-. ��Iaintenance to reduce the �iowth and spread of in�-asi��� � plants is not restricted to chemical applicarions but ma5=include hand remo�-a1,if�varranted; • Dr}�-season irrigation will be provided as necessar�� b�- the properh� o«�ner to hel� en��.0 plant sun ival; • Exterior lights will be directed awa�- from the tributar�T buffer�vhenever possible, :; • Activities that generate e�ces�i��e noise (i.e. �enet-at�rs :�nd air conditi�nin� equi?- be placed a�va� from the ri 7.6 Mitigation Goals, Obje�.. - - , .....: : __: : . ...._.._._ ......:... ... The goals and objectiees tor the proposed non-compensatory� enhancement and restoration actions are based on impro�-ing butfer functions to compensate for temporar�- impacts to the buffer. These actions are capable ot improving«�ater quality and h}-drologic functions and pro�-iding a moderate to high level of habitat funcuon for stream buffer-associated u-ildlife. The goals and objectives of the proposed enhancement actions are as follo��vs: Goal — Improve habitat functions associated ���ith the i�laplewood Creek Tributaryr 0303 buffer by reducing presence of non-native invasive species and increasing presence of habitat features and diversit�-�zithin the temporaril�impacted buffer. Objective 1— Increase plant biodi�ersit}�in areas where Himalayan blackberry- and/or other invasive species are dominant. Performance Standard 1 — r'1 minimum of � native tree and shrub species �uill be present��ithin the enhancement area in all monitoring�•ears. Performance Standard 2 — The enhanced buffer area onsite �vill contain a minimum of 50 percent narive species areal coverage b� Year 2, 60 percent areal coverage b� Year 3, and 75 percent areal coverage percent b��Year 5 of all strata. Objective 2—Effectivel��control and/or eliminate invasive species from the stream buffer enhancement areas. Performance Standard 3—Non-native invasive plants will not make up more than 15 percent total areal cover in anj�growing season follo«ring�'ear 1. 7.7 Plant Materials and Installation 7.7.1 Plant Materials �]1 plant materials to be used for enhancement actions«-ill be nurser�-gro«-n srock trom a reputable, local source. Onl}r native species are to be used; no h�-brids or cultivars ���ill be allo��-ed. Plant material pronided will be ty-pical of their species or variety; if not cuttings the�r will e�hibit normal, densely�-developed branches and �-igorous, fibrous root s��stems. Plants ��-i11 be sound, health�-, ��igorous plants free from defects,and all forms of disease and infestation. 1]8G.U005 BCE/Quadrant—Copperu-ood Residendal Plac Soundeiew Consultants LLC \V'cdand,Pish and\C'ildlife FIabitat A�sessment Repott 18 Retii�ed(ulr]�3,2014 If container stock is used, such marerials shall ha��e been gro��-n in its deliver}� container for not less than sis months but not more than tti��o��ears. Plants shall not exhibit rootbound conditions. Under no circumstances shall container stock be handled b��their trunks, stems, or tops. Seed miYture used for hand or h�rdroseeding shall contain fresh, clean, and neu� crop seed mi�ed b�� an appro��ed metl�od. The mititure is specihed in :�ppendil D. �Vl plant material shal] be inspecred b}� the ��'etland Scientist upon deli��en�. Plant material not conforming to the specifications belo��� �vill be rejected and replaced b�- the plantin� concractor. Rejected plant materials shall be immediately rcmo�-ed from the site. Fertilizer will be in the form of Agroform plant tabs or an approved like form. \Iulch �vill consist of sterile wheat stra�v or clean recycled wood chips appro�imatel�� 1/2 inch to 1 inch in size and 1/2 inch thick. If free of invasive plant species, th� i��ulch marcrial i1�a� b� ���urcc�i tr��in �1������� materials salvaged from the land clearing acti�-ities. 7.7.2 Product Handling, Delivety, and Storage .�11 seed and fertilizer should be delivered in original, unopened, and undamaged containers sho��in� «-eight, analysis, and name of manufacturer. This material should be stored in a manner to prevent «-etting and deteriorarion. r�ll precautions customary in good trade pracrice shall be taken in preparing plants for moving. `�Iorkmanship that fails to meet industr� standards will be rejectec�. Plants will be packed, transported, and handled with care to ensure protection against injun• and � from drying out. If plants cannot be planted immediarel�� upon delicery they� should be protected ��-ith soil, �cet peat moss, or in a manner acceptable to the project biologist. Plants, fertilizer, and mulch not installed immediately upon deli�-ery shall be secured on the site to preeent theft or tampering. No plant shall be bound�vith rope or u-ire in a manner that could damage or break thc branches. Plants transported on open vehicles should be secured �vith a protecti�-e cocering to pre��ent�vindburn. 7.7.3 Preparation and Installation of Plant Materials The planting locarions shou�n in Appendi� D are approximate and subject to modification to m�et site-specific needs. The planting contractor shall verify the location of all elements of the enhancement plan u-ith the ��'etland Scientist prior to installation. The responsible ��'etland Scientist reserves the right to adjust the locations of landscape elements during the installation period as appropriate to the enhancement actions outlined abo�-e. If obstructions are encountered that are not shown on the dra�vings, planting operations �vill ccasc until altcrnatc plant locations have been selected by and/or approved by� the��'etland Scientist. Circular plant pits �vith verrical sides will be excavated for all container stock. The pits should be at least 12 inches in diameter, and the depth of the pit should accommodate the entire root s��stem, The bottom of each pit�vill be scarified to a depth of 4 inches. I�roken roots should be pruned �uith a sharp instrument and rootballs sh�uld be thorou�hl�� soaked ' prior to installation. Set plant material upri�ht in the planting pit to proper grade and alignment, ��'ater plant� thoroughl�• mid�va�- throu�h backtillin� and add �1�,n-oform tablets, ��'ater pits again 1 18G.000� BQ:/Quadrant—Coppenrood Residencial Plat Sound�iew Consultants LLC \V'ctland,Fish and\��ildlife Habicat Assessment Report 19 Recised�ul��14,21i1-1 upon completion of backfilling. No filling should occur around trunks or stems. Do not use frozen or muddy mi�tures for backfilling. Form a ring of soil around the edge of each planting pit tc> retain «ater, and install a 4 to 6 inch la��er of mulch around the base of each container plant. 7.7.4 Temporary Irrigation Specifications ��'hile the nauve species selected tor enhancetnent are hard�� and t�-picall�- thri�-e in north�ti�est conditions, and the proposed enhancement acrions are planned in areas«�ith sufticient h}-droperiods for the species selected, some indi�idual plants might perish due to dr�- conditions. Therefore, irrigation or regular �uatering �vill be provided as necessara for the duration of the first 2 �ro�ving seasons�i�hile the narive plantings become established. 7.7.5 Invasive Plant Control and Removal Invasi�re species to be removed include Himalay-an blackberr�r and all listed notious «-eeds. These species can also be found nearbt�; therefore, to ensure these species do not e�pand follo�ving the enhancement actions, invasive shrubs ���ithin the enhancement and restoration areas will be pretreated ���th a root-killing herbicide approved for use in aquatic sites (i.e. Rodeo) appro�imateh- 30 da��s prior to being cleared and grubbed from the enure u-etland and associated buffer. The pre- treatment u�th herbicide should occur prior to all planned mitigation actions, and spot treatment of ' an}' surviving other invasi�-e vegetation should be performed again each fall prior to leat senescence for a minimum of 3 5-ears. � .� maintenance program requiring annual remo�-a1 of invasi��e species �vithin all «�etland buffer areas b�• a homeo��ner's association follo���ing project completion, and �vritten into the subdivision's Codes, Covenants, and Restricrions, is also recommended. This program should start during the earl�- summer of Year 1 of the monitoring program. 7.8 Maintenance & Monitoring The applicant is committed to compliance �vith the proposed enhancement plan and overall success c>f the project. As such, the applicant will continue to maintain the project, keeping the site free from of non-nauve invasiee vegetation,trash, and�-ard waste. The enhancement site will be monitored for a period of � }-ears «�ith formal inspections by a yualified �&'etland Scientist. The maintenance/monitoring period ��-ill begin upon complerion of an as-built plan and certification from a Professional ��'etland Scientist or Scientist with equivalent yualitications certifying the mitigation was installed per the enhancement and restorarion plan. ,\tonitoring events will be scheduled at the time of construction, 30 da��s after planting, and late in the first through final j-ear's gro�ving seasons in Years 1, 2, 3, and 5. r� closeout assessment�vill also be conducted in �'ear � to ensure the adequate restoration and enhancement measures have been provided. �fonitoring will consist of percent cocer measurements at permanent sampling points, �valk-through surve}�s to identify invasi�re species presence and dead or d��ing restoration plantings, photographs taken at fited photo points, ��•ildlife obsen-ations, and verificauon of dispersion trench function and general qualitatiee buffer function obsen-ations. Percent cocer of all herbaceous species tvill be 1 186.0005 BCE/Quadrant—Coppencood Residential Plac Sound�-iew Consultants LLC \V�cdand,Pish and\C�ildlife Habitat Assescment Rep<�tt 21l Re��ised]uh-1�4,2014 measured along each transect at 30-foot inten�als using a .25 meter quadrant. Average values for each site�vill be determined from all quadrants measured along each transect. 7.9 Reporting Follo�uing each monitoring event, a brief monitoring report detailing the current ecological status of the stream buffer, measurement of performance standards, and management recommendations vvill be prepared and submitted to the Ciry of Renton «=ithin 90 da��s of each monitoring event to ensure full compliance �-ith the mitigation plan, performance standards, and regulatory� conditions of approval. 7.10 Contingency Plans If monitoring results during the first 3 y�ears indicate that performance standards are not being met, it may� be necessar5- to implement all or part of the contingenc}� plan. Careful attention to maintenance is essenrial in ensuring that problems do not arise. Should an�-portion of the site fail t�� �neet the success criteria, a contingency� plan will be developed and implemented �vith City c�t- Renton approval. Such plans are adapuve and should be prepared on a case-b�-case basis to reflec; the failed miugation characteristics. Contingency plans can include additional plant installation, anci plant substitutions including t}pe, size,and location. Contingenc��/maintenance activities may include, but are not liinited ro: 1. Replacing plants lost to vandalism, drought, or diseasc, as neces�an-; 2. Replacing any� plant species �vith a 20 percent or grearer mortalit�� rate after 2 gro«�ing seasons �vith the same species or native species of similar form and function; 3. Irrigaring the enhancement areas onl}- as necessar�- during dr}- «eather if plants appear to be too dn-, �vith a minimal quantit�-of�vater; 4. Reseeding and/or repair of stream buffer areas as necessary� if erosion or sedimentation occurs,or �. Removing all trash or undesirable debris from the stream and buffer areas as necessar�-. 7.11 Early Closeout If the Year 3 monitoring effort indicates all Performance Standards are being met, the Applicant mae petition the Cin� of Renton for earlv closeout of the monitoring period. Such a petition ma�• be made usin� tl�e Year 3 monitoring report and a«-ritten requcst to Cit�- of Renton staff_ 118G.UI IQj BCE;Quadrant—Copperw•ood Residential Plat Jound�ie�t�Consultants LLC 11'etland,Fish and\F'ildlife Habitat Assessment Report 21 Rc�i�ed Juh�14,2014 Chaptc:r 8. Clusure The findings and conclusions documented in this report have been prepared for specific applicauon to the Copperu-ood Residential Plat. The}' have been developed in a manner consistent with tha� level of care and sliill normall� e�ercised b}r members of the environmental science profession currend}� practicing under similar conditions in the area. The conclusions and recommendation� presented in this report are professional opinions based on an interpretation of information currendy� available to us and are made �cithin the operation scope, budget, and schedule of thi. project. No warranty, espressed or implied, is made. In addition, changes in government code�, regulations, or laws may occur. Because of such changes, our observations and conclusions applicable to this site may need to be re��ised wholl��or in part. \�'edand determinations and regulaton�recommendations made b�� Soundview Consultants LLC are based on conditions present at the time of the site �risit and considered preliminary until validated b�� the jurisdictional agencies. Validation of the extent and jurisdictional status of all potentiall�r regulated features by the regulating agenc}' provides a certification, usuall�-�vritten, that the features that �vill, or will not, be regulated bt� the agencies until a specific date or until the regulations are modified. Onle the regulating agencies can provide this certificauon. Since u�etlands and streams are d�-namic communities affected b}�both natural and human activities, changes in wedand boundaries ma�- be e�:pected; therefore, delineations cannot remain valid for an indefinite period of time. Local agencies t�'picallyT recognize the validiry of wedand and stream assessments for a period of� �-ears after complerion of an assessment. De�elopment activities on a �ite 5 years after the complerion of this report may require reeisions. In addition, changes in �overnment codes, regulations, or la�vs ma�� occur. Because of such changes, our observations and conclusions applicable to this site may need to be revised��rholljr or in part. I 1 tiG.Ul1p5 E3CE/Quadrant—Cuppera ood Residential 1'lac Sound�ieu•Consultants[.1� \C��'and,l�i�L a^,d\\ildlife H.iLirac:lssec�mrnc Repnrt ?? Re�ised l��l� 1-1,_'+i:; Chapter 9. Report Summary rlll tield inspecdons, jurisdictional �vedand boundary delineauons, OH��':�f determinations, habitat assessments, and supporting documentation, including this Wetland and Fish & Wildltfe Habitat Assessment prepared for the Co�erwood Resrdential Plat�vere prepared by, or under the direction of, , Jeremy Downs, Jim Carsner, and Hannah Blackstock of Soundview Consultants �-�-�. Jerem}� Do�vns is a Principal Scientist and Emrironmental Planner,Jim Carsner is a certified Professional �X�etland Scientist, and Hannah Blackstock is a Staff Scientist. t1nt-de�-iarions and/or alterations to this document must be appro�-ed by the aforementioned parties at Sound��ie�c Consultants �-L�. Please see ,-lppendis E for a description of professional qualificarions. Sincerel�-, 7/14/14 Jerem�r powns Date Soundview Consultants I-I-� 2907 Harborvie�v Drice k , Gig Harbor,WA 9833� Office: (253) 5148952 ext. 004 Fax: (253) 514-8954 hannah(�sound�-ic�vconsultants.com sws ' 4 7/14/14 b `� � ��o , ames H. Carsner,PWS Date ,�S -. � Kc�,� ' Soundview Consultants I-i-� ��,rejw�q � 2907 Harborc�iew Drive � Gig Harbor,WA 98335 �+�►+o�'" Office: (253) 514-8952 e1t. 008 Fax: (253) 5148954 j im�a�sound�-ie��•consultants.com � 7/14/14 Hannah Blackstock Date Soundview Consultants 7 ir 2907 Harborview Dri�-e Gig Harbor,��G'A 98335 Office: (253) 514-8952 est. 004 ' Fax: (253) 5148954 hannah��ound��ie�t-consultants.com 1186.0005 BCE/Quadrant—Copperu-ood Residenrial Plat Soundciew Consultants LLC �\'edand,Fish and\\'ildGfe Habitat:lssessment Report 23 Re�-ised�ula 14,2014 Chapter 9. References Barber, til., S. Cierebiej, and D. Collins. 2009. Fish Pas.rage Bn�7zer.c a�rrl Srr�face [k%'ater Dia'P)'JIOl1 SCI'PPIIIJIg As.re.r.rr�zerrt artd P�zorrti�atiorr r�fanual. ��'ashington State Department of Fish and��lildlife. Ol�mpia, WA. Brinson, lf. 1�1. 1993. A I��drogeosriorphlc cla.r.rification for wetlands, Technical l�epo�� WI�I'-DE-4. U.S. r'�rm�r =- Eng,ineer��'aterwaS-s E�periment Starion. �'icksburg, 1�1S. I Co�vardin, L.1i. V. Carter, F. Golet, and E.T. LaRoe. 1979. Classiftcntzon of[�etlatad.r aizd Deepavate�• HaGitat.r of t/�e United State.r. U.S. Fish&��'ildlife Service. ��i'ashington D.C. Renton 1�lunicipal Code. 2014. Section 4-3-050, Critical Areas Regulations. Environmental Laboratory. 1987. Co�.r of Engineer.r I�'etlancl.r Delirreatiosz�llajlr�al. Technical Report Y-87- 1, US Army Engineer��'atervvaj-s E�periment Station,Vicksburg, l�iississippi. Granger,T.,T. Hruby,r1. I�IcAlillan, D. Peters,J. Rube�-, D. Sheldon, S. Stanley, E. Stockdale. 2005. I!"etlands in I�'a.rhi�agtott State - l''olunre 2: Guidartce for Protectirrg as�d�1lai�agi�ig tY�etlanrl.r. ��'ashington , State Department of Ecolog}=. Publication #0�-06-008. Olympia,�x'A. [Apri12005]. I Hadle�•, C. 2006. �lle»Jora�rdtr»r. S{�� Creek Preli�rlitlay Plat Fish Pre.ce�lce/Afise�tce Szaz��-.r - East Fork .11aple�vood Creek. Cedarock Consultants, Inc. I��ay 9, 2006. I iitchcock, C.L. and A. Cronquist. 1973. Flora of the Paciftc l��orthu�e.rt Uni��ersity of �Y�'ashington 'I Press. Seatde,��'ashington. � I,ich�-ar, Robert ��'. and John T. Kartesz. 2009. 1\'o��f� Anrerrcart Digital Flora: l�atiorral I�etlatld Plant I rst, version 2.4.0. U.S. Arm}- Corps of Engineers, Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory, Hanoeer, N��', and BONc1P, Chapel Hill, \C. \IunsellOO Color. 2000. �'�1rsn.re110 soil color chart.c. Neur��'indsor,Ne�v York. \atural Resources Conservation Service. 1995. H��dric Soil,r of I�a.r/�itxgtoj�. U.S. Department of rlgriculture. ��'ashington D.C. �Iatural Resources Conservation Service. 2001. H��d�rc SorLr Li.rt: Kirrg Co�rat��, [�''ashington. L'.S. Department of��griculture. ��G'ashington D.C. ()lson, P. and E. Stockdale. 2008. Determilring tl�e Orrlrna3� Higl� l�ater��fark orr Streams in I�'a.rbr���tor� .State. ��4'ashington State Department of Ecology, Shorelands & F.m-ironmental :'lssistance Program, Lacev,��'r1. Ecology Publication # 08-O6-0Ol. Reed, P.B.,Jr., D. Peters,J Goudz���aard, I. Lines, and F. �X-'einmann. 1993. Srr�plenle�rt to ���rtro�ral List of Platlt Species That Occur i�r It'rtlanrl_c: Ao��b�t-e.rt Ke,i��r 9. U.S. Fish & ��'ildlife Ser��ice. Supplement to BioL Rep. 84 (26.9). 11 tiG.�_�(�U� B(:{:;Qu:idr.mt—C��pFri�r�,cd Rr.idcndal Plat Juundciew Conwltancs LLC � 1V�ctlsnd.Fish an�l\\ildlifc Habitat.1s•cssmcnt Rcpurt 24 Re�ised�ulc 1-1,?I�14 Sheldon, D., T. Hrub�-, P. Johnson, K. Harper, A. l�Ic�lillan, T. Granger, S. Stanle��, and E. Stockdale. 2005. ��G'etlands in ��'ashington State - Volume 1: r� S�-nthesis of the Science. ��'ashington State Department of Ecolog}�. Publicarion #0�-06-006. Ol}�mpia,��'A. (i�farch 2005] Sn�•der, Dale E., Philip S. Gale, and Russell F. Pringle. 1973. .Soil Ssrn�ey of Ki�rg County Area, I�asbingtof7. U.S. Department of r�griculture, Soil Consei-�-ation Ser�-ice, in cooperation «-ith the �k'ashington Agricultural Experiment Station. U. S. r�rm� Corps of Engineers. 2008. Clean [f��rter��-1it Jurz.rrliction Follmvirrg the L'.S. Sipreme Comt°r Decision in Raparao.r v. U�tited States �Carabell u L'nited St�ter. EPr'1/USACE. December 2, 2008. U. S. rlrm}' Corps of Engineers. 2010. Regio�ral Ss�pplement to the Co�p.r of EagirJeer.r IYletla�z�l Delir7entio�r :�fa�tstal.• Ik�e.rterit 11lorrritai».r, i%'alley.r, and Coast Region (IIer2.OJ, ed. J.S. �k'akele�r, R.��'. Lich�-ar, and C.V. Noble. ERDC/EL TR-10-3. �'icksbury, IISS: U.S. :�rm�- Fn�ineer Research and Development Center. United States Department of �griculture, �atural Resources Consereation Sen-ice. 2U10. I�ie/rl Indictors of Hydric Soil.r in t/�e lirrited States, I'er.riofz 7.0. L.11. Vasialas, G.`�%. Hurt, and C.V. Noblc (eds.). USDr,,NRCS,in cooperation u�th the Narional Technical Committee for H��dric Soils. ��Uashington State Department of Ecolog,y. 1997. tYla.rhingto��State I�etla�ld.r Irlelrtrfrcntron �r�rd D�li»e�rtioa �1IQ�rrlal. ��'ashington State Department of Ecology�. Publication #96-94. Washington State Department of Ecology. 1997, Ik�ashington State [k'�etland.r I�le�rtflcatioiz ��r�l Delii7eation lfa�rual. ��'ashington State Department of Ecolog�-. Publicaaon #96-94. �X�'ashington State Department of EcologF�, U.S. Army Corps of Engineers Seatde District, and U.S. Environmental Protection r�genc� Region 10. (Ecology�) 2006a. I�'etla��d��litigation i�z I��QSIJ111gI011 State— Part 1:Agerrc�� Policie.r atrd Gui�lance ([/ersion 1). ��'ashington State Department of Ecolog�-. Publicarion #06-06-01 la. Ol}'mpia,��%,-�. � i 11��G.000� IICE/Quadrant—Copperw•ood Residenrial Plat Suund��ew Consultan[s[J.0 � \\ctland,Fish and\�'ildlife Habitat Ascessment Report �� Recised lulc 14,?lil4 Appendix A Methods and Tools Table A-1. Methods and tools used to prepare the report. Parameter Method ot Tool Website Reference ��'edand US,�CE 198? http://el.erdc.usace.arm}•.mi Environmental Laboratory. 198?. Corps of DeGneation �t'etland 1/elpubs/pdY/�vlman87.pdf Engineers��G'edands Delineadon i�ianual. Delineauon Technical Report Y-8?-1,L'S Arm} Engineer 1lfanual \X/aterwat-s Experiment Station,Vicksburg, hlississippi. Western http://wu�v.usace.army.mil U.S.Army Corps of Engineers. 2008.Interim �iountains, /av/cecuo/reg/inte_aridw Regional Supplement to the Corps of Engineers Valleys,and Coast est_sup.pdf ��'etland Delineation Manual:\�'estern Region Interim bfountains,Valleys,and Coast Region,ed.J.S. Regional �x'akeley,R.��'.Lichvar,and C.V.Noble. Supplement ERDC/EL TR-08-13.�'icksburg,`1S:U.S. Army Engineer Research and Development Center. ��G'edand USF1�'S / http://���vu�.fws.gov/nwi/P Cowardin,L.`i.,�'. Carter,F.C.Golet,E.T. Classification Cowardin ubs_Reports/Class_I�lanual LaRoe. 1979. Classificarion of wedands and Classification /class_ddepg.htm deep�vater habitats of the United States. System Government Printing Office,�x'ashington,D.C. H}•drogeomorphic http://el.erdc.usace.arm}�.mi Brinson,Df.D4. (1993)."A h}�drogeomorphic Ciassificarion 1/wedands/pdfs/wrpde4.pd classification for�vedands,"Technical Report (HGl��S}'stem f �x'RP-DE-4,U.S.Army Engineer VG'aterways Esperiment Station,Vicksburg,�fS. ��'etland Renton l�funicipal http://u�ti�v.codepublishing ��'ebsite Raung Code 4-3-050 Jf .com/wa/renton/ Stream Federal Ordinan� http://����v.usace.arm�•.mil Congressional Federal Register 33 Part 328 Delineati�n High��'ater\fark /inet/Eunctions/c�v/cec«-o Definition of VUaters of the United States. Definition /reg/33cfr328.htm Draft State http://ww-w.ecy.�va.gov/pu Olson,P. and E.Stockdale.2008.Determining Ordinary High bs/0806001.pdi the Ordinarv High��Uater l�fark on Streams in ��'ater�fark ��'ashington State.��'ashington State Protocol Department of Ecologv,Shorelands& En�7ronmental Assistance Program,Lace�-,��'A. Ecology Publication#08-06-001. ��4'edand I�ational\�'edand htrp://u-edand_plants.usace.ar Lichvaz,R.��'.2013.1'he National\w'edand Plant Indicator Status Plant List,2013 mt-.mil/ List:2013 wedand rarings.Pht�toneuron 2013-49: ��'edand Ratin s 1-241.Published 17 u1t 2013. Plant�ames USDA Plant http://plants.usda.gov/ \}Uebsite(see Appendix A) Database Soils Data NRCS Soil Survey' http://soils.usda.go�/use/h Natural Resources Conservation Service. ', �-dric/ 2011. H}�dric Soils Lisr.Iiing Counn�, ��'ashington. U.S.Department of Agriculture. VG'ashington D.C. H�dric Soils King County Not available Natural Resources Consetvation Service. Data Hydric Soils List 2001. Hydric Soils Lisr.King County, I �X'ashington. U.S.Department of Agriculture. I �x'ashington D.C. "Threatened ��'ashington �://u1«v.dnr.wa.gov/nh Washington Natural Heritage Progtam and Natural Herita e ata ublished 10/15/08 . Endan red, 11 hG.0005 BCE/Quadrant—Coppencood Residential Plat Sound��ew Consultants I.L.0 \1 cdand,Fish and\�'ildlife Habitat Assessment Report Re�ised Jul��14,2014 Parameter Method or Tool Website Reference E:ndan�crcd Prn�nam � thrcatencd,and scnsiti�c plants of\t'ashin�t<,n. Species and \�i�ashin�non S�ate llepartment of\atural http://u-u�•l.dnr.«�a.go�/n Resources,��'ashington\atural Heritage hp/refdesk/datasearch/wn Program,Oh�mpia,��'�1 hp�redands.pdf ��'ashington http://�vdf�v.�va.gov/hab/p Priority Habitats and Species (PHS) Prioritt�Habitats hspage.htm Program Jfap of priorin-habitats and species .�nd Species in project�-icinin�. �t'ashington Department of Fish and\V'ildlife (��-DE1�'). NOAr1 fisheries http://�c�t�v.nu-r.noaa.�;ov/ �l'ebsite species lict and F.SA-Salmon- maps Listings/Salmon- Populadons/Indes.cfm and http://�v�vw.nm fs.noaa.gov /pr/species/ CSF«'S species http://���1r.fivs.go�-/�cesn�- �t'ebsite lists b�•Counn• afwo/se/SE_List/endan�er ed_Species.asp Species of ��'DF��i'GIS Data http://wdfw.wa.gov/mappi �t'ebsite Locai ng/salmonscape/ Importance Renton�funicipal http://�����e.codepublishing \�'ebsite Codc .com/��-a/rencon/ ll SG.00pS BCEi Quadrant—Copperuvod Residenria]Plat Suundciew Consultants I.LC \�'etland,Fish and 1V'ildlife Habicat,lssessment Reporz Re�ised�ulc 14,2��1-1 Appendix B Background Information This appendix includes a I�ing County Topographic 1lap (B1); USF�k'S National ��'etland Inventory �1ap (B2); City of Renton Critical Areas l�iap (B3); NRCS Soil Survey l�Iap (B4); ��'DFti�'Priority Habitat and Species :�iap (B�); and�!G'DF�k'SalmonScape :�iap (B6. 1186.0005 BCE%Quadrant—Cuppernood Residenual Plac Sound�-ie�c Cunsultants LLC \V'rd:md,Pish and\�'ildlite Hahitat:lssessment Report Re�ised�uh 1},?(li� Appendix B1 — King County Topographic Map � � � � � � � � v � a o�c = Y _ i � � � � � � ��� �� �' "�`�� i � �g - . . oH�ia3: �,,j ?S;.�y Nlt�k. _ �� ' e�5 B �aOJYMI � �y�F i E �,q.E .�, g .�ll�)�C'.('1 �e �� � � �x� y� , � Pro�crt�' �� ,I�:y.�.ati�ctsE �� ' � +. ,s"",,, � � .. - �r ''� ` � o��� 'Q '�►-�►, � � �� ,•ti, ���� � 0 � ; �� � \ � ���� � � - � , � -.L ;��:_� �� O -- . � ,, �B � 3sanvmnnoo�� � C ' � g.��.� v ��I i ° � � � ' �€�� Q i v � C s��� a �� � � � � �'� �,��� � �s�� � v � � : � � � � �y� ���� � ��Y�� �.� � __ � ;t. �� §� �= . � �r �, � �g � � � �- w��� i,� . ��� �s��� � ; ' - � - , �;�avat • t t �� �� � '-` � �g�� � �' �h r � t��� � � # � �... � ��_� � _. ,.� 1 � � �'�°,� � `� � � � �, -�� — ���� � � �, ���� � . �: rt ��"� . � � �� � P'l�'�E 7J � ,�`'' � � ����� �s _� u � � � � �� � � � � �� � ? r � � (�g �-�B � f �__-`� > �g c 3 � /j ��` �~� - �� � � � S�� , V p ` 3S3�YT7Y11f10 �h! ), � F�' s � � � �u�� a � � / u a r� -_ :_ y � �y�I �. ..........� ��_ ....•.Cai.�_....���� ��C. �f�F���: � � .� �.- � ,F � ���� � 11 SG.0005 BCE/Quadrant-Coppenvood Residential Ptat Sound�-iew Consultants I.LC \C'cdand,Pish and\�'ildlife Habitat Assessment Report Re��ised Jule 14,31114 Appendix B2 — USFWS National Wetland Inventory Map 0 � � � N C � � � � � a � � � � � o ; 8 � � � � +�y � � • • w � � O � � � � � �. ! 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D - - --'pt �'i�R1 57-- _. ._ �t----'.4 I +. - >_ ! � Apri!3,2014 1:9,028 o a.o73 a�s o.a m — All SaimonScape Species 0 R 1 42 U.4 km 118G.00C15 BCE/Quadrant—Coppetwood Residenrial Plat Sound�iew Consultants LLC \�'ctland,Fish and\�'ildlife Habit�t:lssessment Report Re��ised�ulc 14,?Ol4 ` � `� �' ' ' ` � � � c A - ��1...1�.1_� � , { �_,�i�� ..� ._i � � � � � � ;� � � � � � � .... �p � � a �a � �p CD a m � � '�._c' .- � � � °�,� �tr--G � �� _ � ('� ��V.4.. � .� � � �.• � a+ a � ' � .�� \ � � � 4� �� � 6�;t,3STtf.3i�,''�� � � SITE �� ° � �� -�� ; Leqend (Fiqures 2 and 3) � n � � � — � � Watercourse � � � �; #5 Survey notes ��1 �, � � :5�� r +�a:Ps. r �s � � � � , Fish observed ••••• •� o p � _ ? _ _..__ _ No fish observed • • • •• • � � � � y Survey Notes � o �' x �.� �s� � m � '� � # Q #�I -Obstruction(see Figure 4) � � � � #2-Boulder pile �, ��F��` r � # � #3-End of canyon reach �; ./ � #4 —Amphibians first noted � LAST FISH OBSERVED f 5�y18Tu_�r #5—Photo(Figure 5) �' ��,�ti. f r�' #6—Photo(Figure 6) � .-�,' .� c'� '��'ti� g�� � � � � �; �� G p C.. . �•� .. SC�+S��'�FI�CI'«"' � � � _ � � G G � � � � 1. -� N � J-, C� Appendix C — Plant Species List This appendit includes a table urith recommended plant species (C1) for the optional buffer enhancement plan. (Altemarive native plants ma}' also be used �vith biologist's approval). Table C1. Enhancement Plan Plant List.' Name Form&Habit Comments �-- Trees �------- Cone bearing evergreen is adapted to a w•ide varien�of soils in Douglas Fu Evergreen tree;extremel}� terms of texture,but reaches its best de�•elopment on cla}'loams, (PseUdotsuga silh-cla}�loams,and silt loams which are deep,moist,and�i-el1 menzresii) dr}�sites. drained. The Douglas-fir is an important Eood for mant•naa��c birds and mammals. Large deciduous tree often mula-stemmed and covered w7th Big-Leaf Maple Deciduous tree;dn�to mosses and other plants.Fmquend}�found w-ith Douglas fir and (Acer macrophyllum) moist sites. on sites disturbed b}>fire or logging.�t�inged seeds descent like helicopters,which increases dispersal. Western Red Cedar Erergreen tree;moist to Cone bearing evergreen deer browse it all�•ear along the coast (Thuja pGcata) ��et soils. occurring on various substrates,commonl}-on moist sites (swamps,�vet ravines,poorly drained depressions). Sitka Spruce E�-ergreen tree;in damp ��er}��-�gorous,broadly conical conifer. Is good on an exposed � (Picea sitchensis) locations. or poor site. Shrubs/Emergents Vine Maple Deciduous shrub;does not Large specimens u-idel}'available;spreads b}-root and seed (Acer circinatum) ahra�•s spread a�gressivel}� Red Currant Deciduous shrub;does not One of our finest ornamental nadces;produces clusters of�vhite (Ribes sanquineum) spread to red tlo���ers Nootka Rose Deciduous shrub;spmads Thickets of spring stems create a formidable banier;produces (Rosa nutkana) by underground runners to attracdve,pink tlou•ers}ollow•ed b��large,red hips;tolerates salt form thickets spray- 'Red Elderberry Deciduous shrub;does not Produces red,non-edible berries;some success reported from (Sambucus racemosa) spread �voody cutrings Salmonberry Deciduous shrub;spreads Spreads quickl}-once established;berries provide tood for a (Rubus spectabilis) by underground runners to �ariet}•of songbirds form thickets Buffer Seed Mix Blue Wildrye (Elymus glaucus) — _ I �1 Idaho Fescue(Festuca idahoensis) � � � Red Fescue (Festuca rubra) f California Brome(Bromus carinatus) Large Leaf Lupine(Lupinus polyphyllus) r- Meadow Barley(Hordeum brachyanterum) ( --- - - - ---__ --__---__ _ ____-- -- ___ __ ___ _ ._ __� �[inal planr sck�non r<�be��rritied h�'th�pru�ret scienu,r. 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' � . � I PATTERN.STAKES AND TREE PLUMB;STAKE PLANTS AS � _ �► - � � NOTED ON LEGEND �''�� � = �� � j � �`���� . =, � �:: r ��., = x � , REMOVE ALL TIES.WRAP 8 CONTAINERS.FREE � j� �, '� � � PERIMETER ROOTS FROM NURSERY BALL � ,� � � �1f� ,n " i �. Ni I '�� j` � 3'DEEP SAUCER FOR WATER � �� ``�j � c"'v c"'•i ' � ,� � ;;'�; Ig � ,`� T .. �%%% EXCAVATE TREE PIT TO MIN.OF 4 TIMES DIA.OF yA ,� _ ;y ,� �, ,#��, ` ROOTBALL AT BALL CENTER,TAPERING PIT �1 _ � ,� � �„,,;, � GRADE TO FINISH GRADE _ /i�:%'%;i�/�% / • O . �i� /!, PIT SPOILS,NURSERY BALL WASTE BACKFILL I � /�;;;ii;�,/,%�//i� / - , I SET BALL ON UNDISTURBED SUBGRADE OR : ' = COMPACTED SOI� �,,\ � z � M '" PLANT LIST e � w � ^ � � _ � NOTE:WORK PERIMETER ROOTS FREE OF NURSERY BALL&SPREAD OVE �� .= 3 � '' (FINAL LOCATIONS AND QUANTITIES TO BE FIELD LOCATED BY RESPONSIBLE WETLAND SCIENTIST) EXCAVATED PIT.BALL 8 PIT TO BE COURSELY SCARIFIED � 7 � � _ � _ � w � � � � ^ TREES (AS NEEDED) � - = � SPACING ' SYMBOL SCJENTlFIC NAME COMMON NAME (FT O.C.) SI2E(MIN) ', r O c r ''" ' , V x _ � ^ N .i _ PSEUDOTSUGA MENZIESII DOUGLAS FIR �$ 2 GAL � ACERMACROPHYIIUM BIGLEAFMAPLE 15 2GAL SHRUB PLANTING DETAIL — � THUJA PLICATA WESTERN RED CEDAR �5 2 GAL NOT TO SCALE z � PICEA S►TCHENSIS SITKA SPRUCE 15 2 GAL LOCATOR LATH(IF SPECIFIED) � N � SHRUBS (AS NEEDED) NOTES: � � SPACING 1. PLANT SHRUBS OF THE SAME SPECIES IN SYMBOL SCIENTIFIC NAME COMMON NAME (FT O.C.) SIZE(MIN) GROUPS OF 3 to 6 AS APPROPRIATE. O �' O � w 2. EXCAVATE PIT TO FULL DEPTH OF ROOT MASS � �, 4� �i ACER ClRCINATUM VINE MAPLE 2 1�L AND CANOPY DIAMETER.SPREAD ROOTS TO � � � � � FULL WIDTH OF CANOPY. � Q z t�j RIBES SANQUINEUM RED CURRANT Z 1 GAL ,ri 3. MIDWAY THROUGH PLANTING ADD AGROFORM a! z x z o � ROSA NUTKANA NOOTKA ROSE 2 1 GAL TABLET AND WATER THOROUGHLY. � �,7� `� `� O•` � 4. BACKFILL TO BE COMPACTED USING WATER +� � � V� SAMBUCUS RACEMOSA RED ELDERBERRY 2 1 GAL ONLY. � ,�j � ;'�< 5. WATER IMMEDIATELY AFTER INSTALLATION. O � 2 '�,� � RUBUS SPECTASIUS SALMONBERRY 2 1 GAL U F, � ���� z � 3 to 4 INCH IAYER OF MULCH , • ;� �-' BUFFER SEED MIX (AS NEEDED) ��/ � a' f'. PERCENT BY QUANTITY /� SCIENTIFIC NAME COMMON NAME VOIUME (APPROX.) %i';. • \� c=.., ELYMUS GLAUCUS BLUE WILDRYE 15 �.�re: 7/14/2014 FESTUCA IDAHOENSIS IDAHO FESCUE 15 FESTUCARUBRA REDFESCUE �5 I��B� IIHG.00OS 30 LBSlACRE BROMUS CARINATUS CALIFORNIA BROME �5 sY: JR/Kl�i LUPINUS POLYPHYLLUS LARGE LEAF LUPINE �5 SCALE: r1S NOTED HORDEUM BRACHYANTHERUM MEADOW BARLEY �5 SHEGT OF 4 Appendix E Biologist Qualifications Jeremy Downs, Princi�al Scientist and Environmental Planner )erem}� Do�vns is the Principal Scientist and En��ironmental Planner for the project with professional training and extensive experience in land use, site planning and design, project coordinarion, permitting and management, marine and ��-edand ecolo��, habitat restoration, ��etland, stream, and benthic delineations and assessments, stream assessments, unciet-��-ater and terrestrial monitc>rin� progr�ams, and mitigation planning and design since 198�. Jeremt- earned a Bachelor's of Science degree in Biolo�n- from the Universit5- of California, Davis. in addition, he studied under the Environmental Risk and Reco�-en� program at the Australian Insritute of :�farine Science. He also holds graduate-level professional certifications in various advanced wetland :cience and management programs from both Portland State Universin� and San Francisco State L'ni��ersitt-, and he has received professional training in Salmonid Biolo�- from the L"niversin� of California Estension. Jerem}' is a certified wetlands delineator under US Arm}- Corps of Engineers guidelines. He has been � formallj� trained in the use of the ��'ashington State ��%etland Raung S}'stem, Determination of Ordinary High `�'ater i�lark, Designing Compensator�- �firigauon and Restoration Projects, and Revie�ving \t�etland �litigation and titonitoring Plans from the L"S �rmy Corps of Engineers and Vi-'ashington State Department of Ecology, and in conducting Biological Assessments from the��Uashington Department of Transportation. He is also a Pierce Counn� Qualified ��'etland Specialist and Fisheries Biologist, and he hc�lds similar qualit7cations from other jurisdictions. I James H. Carsner, Senior Scientist I� lim Carsner, a certitied Professional ��'edand Scientist (#1461) �vith professional training and extensive �sperience in planning and design, project coordination, permitting and management, aquatic and «-etland ecolog��, habitat restoration, wedand, stream, and benthic delineations and assessments, stream assessments, and mitigarion planning and monitoring since 1979. Jim earned a Bachelor's of Science , degree from the L`niversit}' of��G'ashington, College of Fisheries and undertook post-graduate studies in �i �vetland ecolog�- at Pordand State University He has served on the Board of Directors of the I �t'ashington State��G'eed �lssociation and instructed courses on pesdcide laws, regularions,and uses. Jim has been formally trained in the use of the��'ashington State��'etland Rating St-stem, Determination , of Ordinar� High ��'ater lfark, Designing Compensaton- �liugation and Restoration Projects, and � Reviewing «'etland i�Iitigation and �Ionitoring Plans from the US rlrmt� Corps of Engineers and ' ��'ashington State Department of Ecolog�-. He is also a Pierce County Qualified ��G'etland Specialist and � Fisheries Biologist, and he holds similar qualificarions from other jurisdictions. Hannah Blackstock, Staff Scientist Hannah Blackstock is a Staff Scientist �vith a background in both forest and �vetland ecologyr and fisheries biology and experience with various Federal agencies. Hannah earned a Bachelor's of Science ��-ith a double major in Environmental Science and Resource �Ianagement as �rell as Aquatic and I�isheries Sciences at the Universit}� of��`ashington. Hannah has an extensi�re kno�vledge of restorarion ecolo�-, ranging in topics such as soils, plant familiarih', h�Tdrolog�-, and �yetland ecolo�-. Furthermore, she has been certified b�- the ��G'ashington Department of Ecology� in the use of the \�'ashington State � �\'etland Rating S��stem and Selecting ��'etland �fiugation Sites Using a �x'atershed Approach and has , received training from the P���'lnvasi�re Plant Council on the identification of newl}-emerging in<<asive �' plant species. 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' L I � �L ` . _ _ -- -- �� ,,rl.�j .,,,-r� .--��. .�,.� � 72 ST. 200 W - � � � -- _ _ - � m.. .�� __� ._ _ .� --- j ..�. j ��.r_v� __, ,�r v�• _� -- �••.� 6�L.EVIJ�.WA980UB 'S "q aUi �: v-+a�w -- "�n •-....__._ ,. ... __ - - - - — _ � - �J��.Ij'•l"'..:r.�-- ■ ■ 7.2 Hydraulic Pro�ect Approval -' Washington Department of Fish 8 wldlife � HYDRAULIC PROJECT APPROVAL PO Box 43234 FiSH����1ILDLI�E Olympia,WA 98504-3234 (360)902-2200 Issued Date: December 03, 2014 Permit Number: 2014-4-391+01 Project End Date: December 02, 2019 FPA/Public Notice Number: N/A Application ID: 1989 PERMITTEE AUTHORIZED AGENT OR CONTRACTOR Quadrant Homes Soundview Consultants LLC ATTENTION: Barbara Rodgers ATTENTION: Hannah Blackstock 14725 Southeast 36th, Suite 200 2907 Harborview Dr Bellevue, WA 98006 Gig Harbor, WA 98335-1911 Project Name: Copperwood Residential Plat Project Description: The Applicant proposes a single-family residential development within the approximately 12.68- acre subject property. The proposed project includes demolition of all but one of the existing residences, removal of scrap and debris associated with the previous residential land use, clearing and grading for construction of approximately 47 residential housing units with driveways, parking areas, associated utilities and infrastructure, and buffer reduction, averaging, and enhancement actions. The proposed project will also provide fully engineered stormwater facilities to the City of Renton's standards. The southwest facilities will require placement of a stormwater outfall and pervious walking trail along with minor grading actions within the stream buffer and minor buffer reduction via buffer averaging in the southeast corner of the site. The alignment of the outfall has been designed to avoid significant native conifers, and temporary impacts will be limited to the smallest area necessary to allow installation located immediately outside of OHW. Any impacts associated with the installation of this outfall, low-impact trail, minor grading, and buffer averaging will be mitigated for through non- compensatory buffer enhancement actions. , PROVISIONS 1. The project may begin immediately and shall be completed by December 2, 2019, provided outfall construction within the ordinary high water line (OHWL) shall occur only between July 1 and September 30. 2. Work shall be accomplished per plans and specifications submitted to and approved by the Washington Department of Fish and Wildlife (WDFW) entitled, "COPPERWOOD BUFFER AVERAGING AND ENHANCEMENT PLAN", dated I November 10, 2014, except as modified by this Hydraulic Project Approval (HPA). A copy of these plans and this HPA shall be available on site during construction. ' 3. The stream bank at the point of the discharge shall be armored to prevent scouring. 4. Excavation for the placement of the outfall structures or armoring materials shall be isolated from the wetted perimeter. 5. Equipment used for this project shall be free of external petroleum-based products while working around the stream. Equipment shall be checked daily for leaks and any necessary repairs shall be completed prior to commencing work activities along the stream. 6. All waste material such as construction debris, silt, excess dirt or overburden resulting from this project shall be deposited above the limits of floodwater in an approved upland disposal site. � Page 1 of 5 � Washington Department of Fish&Wildlife � HYDRAULIC PROJECT APPROVAL POBox43234 a�^����: Olympia,WA 98504-3234 FlSHaa fi7LDLfFE (360)902-2200 Issued Date: December 03, 2014 Permit Number: 2014-4-391+01 Project End Date: December 02, 2019 FPA/Public Notice Number: N/A Application ID: 1989 7. Disturbance of the streambed and banks and wetlands and their associated vegetation shall be limited to that necessary to install the project. Affected areas of vegetation shall be restored to preproject or improved habitat configuration. Prior to December 31 of the year of project construction, the disturbed areas of vegetation shall be revegetated with native woody species approved by the Area Habitat Biologist (AHB) listed below. Plantings shall be maintained as necessary for three or more years to ensure 80 percent or greater initial survival of each species or a contingency species approved by the AHB. 8. If at any time, as a result of project activities, fish are observed in distress, a fish kill occurs, or water quality problems develop (including equipment leaks or spills), immediate notification shall be made to the Washington Emergency Management Division at 1-800-258-5990, and to the AHB. 9. Erosion control methods shall be used to prevent silt-laden water from entering the stream. These may include, but are not limited to, straw bales, filter fabric, temporary sediment ponds, check dams of pea gravel-filled burlap bags or other material, and/or immediate mulching of exposed areas. 10. Prior to starting work, the selected erosion control methods (Provision 9) shall be installed. Accumulated sediments shall be removed during the project and prior to removing the erosion control methods after completion of work. 11. Extreme care shall be taken to ensure that no petroleum products, hydraulic fluid, fresh cement, sediments, sediment-laden water, chemicals, or any other toxic or deleterious materials are allowed to enter or leach into the stream. LOCATION #1: Site Name: Copperwood Plat , Renton, WA _ _--- __ __ ;_.__ _._ ._ __. _ WORK START: December 3, 2014 '� WORK END: December 2, 2019 WRIA Waterbodv: Tributary to: -� i 08 - Cedar- Sammamish Maplewood Creek(rb) Cedar River 1 4 E : i n� Townshi� Ranae: Latitude: L n i Countv' SE 1/4 15 23 N 05 E 47.479563 -122.152471 King j Location#1 Drivin9 Directions To access the subject property from the Tukwila area, via lnterstate 405 northbound, take Exit 4 toward Washington- 900/Bronson Way. Turn right onto Washington-169 north. After approximately 360 feet, take the first right onto Sunset Boulevard North. After 0.2 mile, take the first right onto Northeast 3rd Street. Proceed 0.9 mile and continue onto Northeast 4th Street. Proceed 1.0 mile and tum right onto Duvall Avenue Northeast. After 0.5 mile, Duvall Avenue '� Northeast turns slightly to the left and becomes Southeast 2nd Place. The subject property will be located on the right side � of Southeast 2nd Place after approximately 0.2 mile. APPLY TO ALL HYDRAULIC PROJECT APPROVALS Page2of5 Washington Department of Fish &Wildlife � HYDRAULIC PROJECT APPROVAL POBox43234 u�A�^^m�^��+ Olympia,WA 98504-3234 F(Sfl m,a W7LDLIFE (360)902-2200 Issued Date: December 03, 2014 Permit Number: 2014-4-391+01 Project End Date: December 02, 2019 FPA/Public Notice Number: N/A Application ID: 1989 This Hydraulic Project Approval pertains only to those requirements of the Washington State Hydraulic Code, specifically Chapter 77.55 RCW. Additional authorization from other public agencies may be necessary for this project. The person (s) to whom this Hydraulic Project Approval is issued is responsible for applying for and obtaining any additional authorization from other public agencies (local, state and/or federal) that may be necessary for this project. This Hydraulic Project Approval shall be available on the job site at all times and all its provisions followed by the person (s)to whom this Hydraulic Project Approval is issued and operator(s) performing the work. This Hydraulic Project Approval does not authorize trespass. The person(s)to whom this Hydraulic Project Approval is issued and operator(s) performing the work may be held liable for any loss or damage to fish life or fish habitat that results from failure to comply with the provisions of this Hydraulic Project Approval. Failure to comply with the provisions of this Hydraulic Project Approval could result in a civil penalry of up to one hundred dollars per day and/or a gross misdemeanor charge, possibly punishable by fine and/or imprisonment. All Hydraulic Project Approvals issued under RCW 77.55.021 are subject to additional restrictions, conditions, or revocation if the Department of Fish and Wildlife determines that changed conditions require such action. The person(s) to whom this Hydraulic Project Approval is issued has the right to appeal those decisions. Procedures for filing appeals are listed below. MINOR MODIFICATIONS TO THIS HPA:You may request approval of minor modifications to the required work timing or to the plans and specifications approved in this HPA. A minor modification to the required work timing means up to a one-week deviation from the timing window in the HPA when there are no spawning or incubating fish present within the vicinity of the project. You may request subsequent minor modifications to the required work timing. A minor modification of the plans and specifications means any changes in the materials, characteristics or construction of your project that does not alter the projecYs impact to fish life or habitat and does not require a change in the provisions of the HPA to mitigate the impacts of the modification. Minor modifications do not require you to pay additional application fees or be issued a new HPA. If you originally applied for your HPA through the online Aquatic Protection Permitting System (APPS), you may request a minor modification through APPS. A link to APPS is at http://wdfw.wa.gov/licensing/hpal. If you do not use APPS you must submit a written request that clearly indicates you are seeking a minor m�dification to an existing HPA. Include the HPA number and a description of the requested change and send by mail to:Washington Department of Fish and Wildlife, PO Box 43234, Olympia, Washington 98504-3234, or by email to HPAapplications@dfw.wa.gov. Do not include payment with your request. You should allow up to 45 days for the department to process your request. MAJOR MODIFICATIONS TO THIS HPA:You may request approval of major modifications to any aspect of your HPA. Any approved change other than a minor modification to your HPA will require issuance of a new HPA. If you paid an application fee for your original HPA you must pay an additional$150 for the major modification. If you did not pay an application fee for the original HPA, no fee is required for a change to it. If you originally applied for your HPA through the online Aquatic Protection Permitting System (APPS), you may request a major modification through APPS. A link to APPS is at http://wdfw.wa.gov/licensing/hpa/. If you do not use APPS you must submit a written request that clearly indicates you are requesting a major modification to an existing HPA. Include the HPA number, check, and a description of the requested change. Send your written request and payment, if applicable, by mail to: Washington Department of Fish and Wildlife, PO Box 43234, Olympia, Washington 98504-3234. You should allow up to 45 days for the department to process your request. Page 3 of 5 Washington Department of Fish&Wildlife � HYDRAULIC PROJECT APPROVAL POBox43234 ��- - Olympia,WA 98504-3234 FISH a�e�1TLDLIFE (360)902-2200 Issued Date: December 03, 2014 Permit Number: 2014-4-391+01 Project End Date: December 02, 2019 FPA/Public Notice Number: N/A Application ID: 1989 APPEALS INFORMATION If you wish to appeal the issuance, denial, conditioning, or modification of a Hydraulic Project Approval (HPA), Washington Department of Fish and Wildlife (WDFW) recommends that you first contact the department employee who issued or denied the HPA to discuss your concerns. Such a discussion may resolve your concerns without the need for ' further appeal action. If you proceed with an appeal, you may request an informal or formal appeal. WDFW encourages you to take advantage of the informal appeal process before initiating a formal appeal. The informal appeal process includes a review by department management of the HPA or denial and often resolves issues faster and with less legal complexity than the formal appeal process. If the informal appeal process does not resolve your concerns, you may advance your appeal to the formal process. You may contact the HPA Appeals Coordinator at �i60) 902-2534 for more information. A. INFORMAL APPEALS:WAC 220-110-340 is the rule describing how to request an informal appeal of WDFW actions taken under Chapter 77.55 RCW. Please refer to that rule for complete informal appeal procedures. The following information summarizes that rule. A person who is aggrieved by the issuance, denial, conditioning, or modification of an HPA may request an informal appeal of that action. You must send your request to WDFW by mail to the Washington Department of Fish and Wildlife HPA Appeals Coordinator,600 Capitol Way North, Olympia, Washington 98501-1091;e-mail to HPAapplications@dfinr.wa.gov;fax to (360) 902-2946; or hand-delivery to the Natural Resources Building, 1111 Washington St SE, Habitat Program, Fifth floor. WDFW must receive your request within 30 days from the date you receive notice of the decision. If you agree, and you applied for the HPA, resolution of the appeal may be facilitated through an informal conference with the WDFW employee responsible for the decision and a supervisor. If a resolution is not reached through the informal conference, or you are not the person who applied for the HPA, the HPA Appeals Coordinator or designee will conduct an informal hearing and recommend a decision to the Director or designee. If you are not satisfied with the results of the informal appeal, you may file a request for a formal appeal. B. FORMAL APPEALS:WAC 220-110-350 is the rule describing how to request a formal appeal of WDFW actions taken under Chapter 77.55 RCW. Please refer to that rule for complete formal appeal procedures. The following information summarizes that rule. A person who is aggrieved by the issuance, denial, conditioning, or modification of an HPA may request a formal appeal of that action. You must send your request for a formal appeal to the clerk of the Pollution Control Hearings Boards and serve a copy on WDFW within 30 days from the date you receive notice of the decision. You may serve WDFW by mail to the Washington Department of Fish and Wildlife HPA Appeals Coordinator,600 Capitol Way North, Olympia, Washington 98501-1091; e-mail to HPAapplications@dfw.wa.gov; fax to (360) 902-2946; or hand-delivery to the Natural Resources Building, 1111 Washington St SE, Habitat Program, Fifth floor. The time period for requesting a formal appeal is suspended during consideration of a timely informal appeal. If there has been an informal appeal, you may request a formal appeal within 30 days from the date you receive the Director's or designee's written decision in response to the informal appeal. C. FAILURE TO APPEAL WITHIN THE REQUIRED TIME PERIODS: If there is no timely request for an appeal, the WDFW action shall be final and unappealable. Page 4 of 5 Washington Department of Fish&Wildlife � HYDRAULIC PROJECT APPROVAL PO Box 43234 - ;4',. .° ;>��-- Olympia,WA 98504-3234 '�H and{��L� (360) 902-2200 Issued Date: December 03, 2014 Permit Number: 2014-4-391+01 Project End Date: December 02, 2019 FPA/Public Notice Number: N/A Application ID: 1989 Habitat Biologist Larry.FisherQa dfw.wa.gov ��� for Director Larry Fisher 425-313-5683 WDFW Page 5 of 5 7. 3 NPDES Permit from the Department of Ecology dated February 19, 2015 ..� 't;�: �:�. ',t; r f�i< i:�'��, Si�1(E ()F WAtiHINGT()ti UEF'AKTMENT OF ECULUGY PU Boi �77600 •Olympia, WA 9850d-i 61/0 • 3bll--1117-hUflp :l 1 %�,r 11',i.hin�lnn RelaY Servicr • Prnunc �s ilh a ,pei��h r/i�,ihilil y can c�r/!�t."-N i t-/�t-i l February 19, 2015 Barbara Rodgers � Quadrant Homes I 14725 SE 36`� Street, Suite 200 Bellevue,WA 98006-1606 RE: Coverage under the Construction Stormwater General Permit I� Permit number: WAR302601 Site Name: Copperwood Location: 4905 SE 2°d Place Renton,WA County: King Disturbed Acres: 9.9 Dear Ms. Rodgers: The Washington State Department of Ecology(Ecology)received your Notice of Intent for coverage under Ecology's Construction Stormwater General Permit(permit). This is your permit coverage letter. Your permit coverage is effective on February 19,2015. Please retain this permit coverage letter with your permit(enclosed), stormwater pollution prevention plan(SWPPP),and site log book. These materials are the o�cial record of permit coverage for your site. Please take time to read the entire pernut and contact Ecology if you have any questions. Appeal Process You have a right to appeal coverage u.nder the general permit to the Pollution Control Hearing Board (PCHB)within 30 days of the date of receipt of this letter. This appeal is limited to the general permit's applicability or non-applicability to a specific dischazger. The appeal process is governed by chapter 43.21 B RCW and chapter 371-08 WAC. "Date of receipY' is defined in RCW 43.21 B.001(2). �� NPDES Permit from the Department of Ecology dated February 19, 2015 �, - . : ::: �"t::: . iii'� f�. �: ���'. "'i. STATE OF WAtiHI�tiGTON DEPARTMENT OF ECOLUGY PO Box�17600•Olympia. WA 9H50J-7600• .?50-�iQ7-bllq(1 i 11 for Washin,�t�►n Relay Servic•� • Persnn< <silh a cpeech disahility can ra/!N77-N33-63�1t February 19, 2015 Barbara Rodgers Quadrant Homes 14725 SE 36`�Street, Suite 200 Bellevue, WA 98006-1606 RE: Coverage under the Construction Stormwater General Permit Permit number: WAR302601 Site Name: Copperwood Location: 4905 SE 2"d Place Renton,WA County: King Disturbed Acres: 9.9 Dear Ms. Rodgers: The Washington State Department of Ecology(Ecology)received your Notice of Intent for coverage under Ecology's Construction Stormwater General Permit(permit). This is your permit coverage letter. Your pernut coverage is effective on February 19,2015. Please retain this permit coverage letter with yaur permit(enclosed), stormwater pollution prevention plan(SWPPP),and site log book. These materials are the o�icial recflrd of permit coverage for your site. Please take time to read the entire pernut and contact Ecology if you have any questions. Appeal Process You have a right to appeal coverage under the general permit to the Pollution Control Hearing Board (PCHB)within 30 days of the date of receipt of this letter. This appeal is limited to the general permit's applicability or non-applicability to a specific discharger. The appeal process is governed by chapter 43.21 B RCW and chapter 371-08 WAC. "Date of receipt" is defined in RCW 43.21 B.001(2). ��.1 8.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN (CSWPP) ANALYSIS AND DESIGN A. Erosion and Sediment Control (ESC) Plan Analysis and Design The erosion and sediment control plans were prepared in accordance with the 2009 King County Surface Water Design Manual, 2010 City of Renton Amendments to the KCSWDM, and standard industry practices throughout the construction process to limit the amount of sediment traveling into the downstream systems. The permanent drainage facility in Tract B will be constructed to provide sediment retention on site. Additional BMPs that are proposed include a rock construction entrance located at the ', intersections of Road A and S.E. 2nd Place, as well as Road C and S.E. 2nd Place, silt fence where needed, straw mulch for the areas that reach final grade in the lot areas, V- ditches with rock check dams, and hydroseeding. Clearing limits have been established as shown on the engineering plans. The following outline summarizes the basin area breakdowns for sediment pond sizing. The developed 2-year peak flow rate from the Post Developed Basin from Section 4.0 of this report was used for calculating the surface area required. The surface area was calculated using the following equation: SA= 2 x Q, = 2080 sf per cfs of inflow. 0.00096 Sediment Pond (Tract B permanent facilitv) QZ = 1.77 cfs SA Required = 3,682 sf SA Provided = 12,723 sf(at elevation 377.00) The sizing of the dewatering orifice can be determined as follows: Ao= SA 2h o.s 0.6 x 3600 Tg 5 Ao= orifice area (sf� SA= Pond Surface Area (s� h = height of riser-4 ft T= 24 hours g = 32.2 ft1s2 Ao = 3,682 x(2x4)°5 = 0.035 ft2 0.6 x 3600 (24) (32.2)o.s Diameter(D)= 24 x(Ao/n)°5= 2.53 in B. Stormwater Pollution Prevention and Spill (SWPPS) Plan Design A SWPPS plan will be provided as part of the NPDES Permit submittal at a later date. I 16834.015.doc 9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 9.1 Bond Quantities 9.2 Facility Summary Form 9.3 Declaration of Covenant for Impervious Surface Limit 9.4 Declaration of Covenant for Inspection and Maintenance of Stormwater Facilities and BMPS 16834.015.doc � � �--+ �•-+ � � � � � � � W r . V� Site Improvement Bond Quantity Worksheet S,5 Webdate: 02/2?J2013 � King County Department of Permitting &Environmental Review 35030 SE Douglas Street, Suite 210 Snoqualmie, Washington 98065-9266 For alternate formats, call 206-296-6600. 206-296-66Q0 TTY Relay 711 Project Name: Plat of Copperwood Date: 2/12/2015 �ocation: 143rd Avenue SE and SE 2nd Place Project No.: U14006283 Activity No.: Note: All prices include labor, equipment, materials, overhead 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: 11/26/2008 Siie improvement bond quantiry worksheet.xls Report Date: 4/6/2015 Site Improvement Bond Quantity Worksheet S,5 Wabdate: 02/22/2013 Unit #of Reference# Price Unit Gtuantity Applications Cost EROSION/SEDIMENT CONTROL Number Backfill&compaction-embankment ESC-1 $ 5.62 CY Check dams,4"minus rock ESC-2 SWDM 5.4.6.3 $ 67.51 Each 24 1 1620 Crushed surfacin 1 1/4" minus ESC-3 WSDOT 9-03.9 3) $ 85.45 CY Ditchin ESC-4 $ 8.08 CY Excavation-bulk ESC-5 $ 1.50 CY Fence,silt ESC-8 SWDM 5.4.3.1 $ 1.38 LF 2525 1 3485 Fence,Temporary(NGPE ESC-7 $ 1.38 LF 700 1 966 H droseeding ESC-8 SWDM 5.4.2.�1 $ 0.59 SY 38077 1 22465 Jute Mesh ESC-9 SWDM 5.4.22 $ 1.45 SY Mulch, b hand,straw,3"dee ESC-14 SWDM 5.4.2.1 $ 2.01 SY Mulch, b machine,straw,2"deep ESC-11 SWDM 5.4.2.1 $ 0.53 SY Pipin ,temporary, CPP, 6" ESC-12 $ 10.70 LF Pi in ,temporary,CPP, 8" ESC-13 $ 16.10 LF Pi in ,tem ora ,CPP, 12" ESC-14 $ 20.70 LF 70 1 1449 Plastic covering,6mm thick, sandbagged ESC-15 SWDM 5.4.2.3 $ 2.30 SY Ri Ra , machine laced;slopes ESC-16 WSDOT 9-13.1(2) $ 39.08 CY Rock Construction Entrance,50'x15'xi' ESC-17 SWDM 5.4.4.1 $ 1,464.34 Each Rock Construction Entrance, 100'x15'xi' ESG18 SWDM 5.4.4.1 $ 2,928.68 Each 1 1 2929 Sediment pond riser assembl ESG19 SWDM 5.4.5.2 $ 1,949.38 Each 1 1 1949 Sediment trap,5' hi h berm ESC-20 SWDM 5.4.5.1 $ 17.91 LF Sed.trap,5'high,riprapped spillway berm section ESC-21 SWDM 5.4.5.1 $ 68.54 LF Seeding, b hand ESC-22 SWDM 5.4.2.4 $ 0.51 SY Soddin , 1"deep, level round ESC-23 SWDM 5.4.2.5 $ 6.Q3 SY Soddin , 1"deep,sloped round ESC-24 SWDM 5.4.2.5 $ 7.45 SY TESC Supervisor ESC-25 $ 74.75 HR Water truck, dust control ESC-26 SWDM 5.4.7 $ 97.75 HR WRITE-IN-ITEMS **** (see paqe 9) Each ESC SUBTOTAL: $ 34,863.23 30%CON71NGE1VCY&MOBILIZATION: $ 10,458.97 ESC TOTAL: $ 45,322.20 COLUMN: A Page 2 of 9 Unit prices updated: 02/12/02 Version: 11/26/2008 Site improvement bond quantity worksheet.xls Report Date� 4/6/2015 � Site Improvement Bond Quantity Worksheet Wcbdate 12l0?J2008 . .,., ..�.. _.. ,.. . _ . . , .�,. .�: _ _ , _ . �.. ., Exfsting Future Pubiic Private �uantlty Completed Right-of-Way Right of Way improvements (Bond Reduction)• &Dralna e Facilitles Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Com lete Cost GENERALITEMS No. Backfill&Com action-embankment GI-1 $ 5.62 CY 5830 32,784.60 15760 88,57120 Backfill&Com action-tronch GI-2 $ 8.53 CY CleadRemove Brush,b hand GI-3 $ 0.36 SY Clearin Grubbin ree Removal GI-4 $ 8,876.16 Acre 1 8,876.16 Excavation-bulk GI-5 $ 1.50 CY 4000 6,000.00 10810 16,215.0� Excavation-Trench GI-6 $ 4.06 CY Fencin ,cedar,6'hi h GI-7 $ 18.55 LF Fencin ,chaln link,vin I coated, 6'hf h GI-8 $ 13.44 LF 50 672.00 800 10,752.00 Fencin ,chaln Ifnk, ate,vin I coated, 2 GI-9 $ 1,271.81 Each 2 2,543.fi2 Fencin ,split rall,3'hi h GI-1 $ 12.12 LF 1400 16,968.00 Fill 8 compact-common barrow Gl-11 $ 22.57 CY Fill&compact- ravel base GI-12 $ 25.48 CY Fill&compact-screcned topsoit GI-13 $ 37.85 CY Gabion, t2'dee ,stone fille�f inesh GI-14 $ 54.31 SY Gabion, 18"deep,stone filled mesh GI-15 $ 74.85 SY Gabion,36"deep,stone filled mesh GI-16 $ 132.48 SY Gradin ,fine,b hand GI-17 $ 2.02 SY Gradin ,fine,with rader GI-18 $ 0.95 SY Monuments,3'lon GI-19 $ 135.13 Each 2 270.26 4 540.52 Sensitive Areas Si n GI-20 $ 2.88 Each 34 97.92 Soddin , 1"dee ,slo ed round GI-21 $ 7.46 SY Surve in ,Ilne& rade GI-22 $ 788.26 Da Surve in ,lot IocatioMines GI-23 $ 1,556.64 Acre Traffic control crew 2 fla ers GI-24 $ 85.18 HR Trail,4"chi ed wood GI-25 $ 7.59 SY Trail,4°crushed cinder GI-26 $ 8.33 SY Trail,4"top course GI-27 $ 8.19 SY Wall,retainin ,concrete GI-28 $ 44.16 SF SO 3,532.80 Wall,rockery GI-29 $ 9.49 SF 180 1,708.20 Pagc 3 of 9 SUBTOTAL 4,475.06 52,600.74 132,436.48 Unit prices updated: 02/12/02 'KCC 27A authorizes only one bond reductfon. Version: 11/2fi/OS Slte improvement bond quantiry worksheet.xls Report Date:4/fi/2015 Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008 Existing Future Public Prtvate Bond Reductlon' Right-of-way Right of Way Improvements &Draina e Facilfties Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cosi ROADIMPROVEMENT Na AC Grindin ,4'wide machine<1000sy RI-1 $ 28.00 SY 550 15,400.Q0 AC Grindin ,4'wide machine 1000-200 RI-2 $ 15.00 SY AC Grindfn ,4'wide machine>2000s RI-3 $ 7.00 SY AC Removal/DlsposaVRe sir RI-4 $ 67.50 SY 550 37,125.00 Barricade, e I RI-5 $ 30.03 LF Barricade,t pe III(Permanent) RI-6 $ 45.05 LF Curb 8 Gutter,rolled RI-7 $ 17.00 LF Curb&Gutter,vertical RI-B $ 12.56 LF 650 8,125.00 2750 34,375.00 Curb and Gutter,demolitlon and dis osa RI-9 $ 18.06 LF Curb,extruded asphalt RI-10 $ 5.50 LF Curb,extruded concrete R1-11 $ 7.00 LF Sawcut,asphalt,3"de th RI-12 $ 1.85 LF 1385 2,562.25 � Sawcut,concrete, er 1"de th RI-13 $ 1.69 LF Sealant,asphalt RI-14 $ 1.25 LF Shoulder,AC, (see AC road unit price) RI-15 $ - SY Shoulder, ravel,4°thick RI-16 $ 15.00 SY Sidewalk,4"thick RI-17 $ 35.00 SY 360 12,600.00 1530 53,550.00 Sidewalk,4"thick,demolition and dis os RI-18 $ 29.5Q SY Sidewalk,5"thick !il-19 $ 38.50 SY Sidewatk,5"thick,demolition and dispos RI-20 $ 37.5Q SY Si n,handica RI-21 $ 85.28 Each Strl In , er stall RI-22 $ 5.82 Each Stri in ,thermoplastic, for Crosswalk RI-23 $ 2.38 SF 72 171.36 Stnping,4"reflectorized line RI-2n $ 0.25 LF Page 4 of 9 SUBTOTAL 75,983.61 87,925.00 Unit prices updated: 02/12/Q2 'KCC 27A authorizes only one bond reduction. Version: 11/26/08 Site improvement bond quantity worksheet.xls Heport Date:4/6/2015 � - Web date: 12/02/2008 Site Improvement Bond Quantity Worksheet ' Existing Future Public Prlvate Bond Reductlon• Rtght-of-way Right of Way Improvements &Drainage Facilities Quant. Unit Price Unit QuanL Cost Quant. Cost Quant. Cost Com tete Cost ROAD SURFACING (4"Rock=2.5 base&1.5"top course) For'93 KCRS(6.5"Rock=5"base&1.5"top course) I, For KCRS'93,(additional 2.5"base)add RS-1 $ 3.60 SY ! AC Overia ,1.5"AC RS-2 $ 1125 SY 460 5,175.00 AC Over►ay,2"AC RS-3 $ 15.00 SY AC Road,2',4'rock, Flrst 2500 SY RS-4 $ 21.00 SY 970 20,370.00 2500 52,500.00 1200 25,200.00 AC Road,2",4"rock,Q .over 2500SY RS-5 $ 19.00 SY 1135 21,565.00 AC Road,3',4"rock,First 2500 SY RS-6 $ 23.30 SY AC Road,3',4"rock,Qt .over 2500 SY RS-7 $ 21.00 SY AC Road,5",First 2500 SY RS-8 $ 27.60 SY AC Road,5',Q .Over 2500 SY RS-9 $ 25.00 SY AC Road,6',First 2500 SY S-1 $ 33.10 SY AC Road,6",Qty.Over 25U0 8Y S-11 $ 30.00 SY As halt Treated Base,4"thick RS-1 $ 20.00 SY Gravel Road,4"rock,First 2500 SY S-1 $ 15.00 SY Gravel Road,4'rock,Q .over 2500 SY S-1 $ 8.50 5Y PCC Road,5",no base,over 2500 SY RS-1 $ 27.00 SY PCC Road, 6",no base,over 2500 SY RS-1 $ 25.50 SY Thickened Edge RS-1 $ 8.60 LF Page 5 of 9 SUBTOTAL 25,545.00 74,065.00 25,200.00 Unit prices updated: 02/12/02 'KCC 27A authorizes only one band reduction. Version: 11/26/OS Site improvement bond quantity worksheet.xls Report Date:4/6/2015 ' � � � WBtI(�d�d: �Z�2/2��� Site Improvement Bond Quantity Worksheet Existing Future Public Private Bond Reduction' Aight-of-way Right of Way Improvements &Drainage Facilities Quant Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost DRAINAGE (CPP=Corrugated Plastic Pipe,N12 or Equivalent) For Culvert prices, Average of 4'cover was aeaumed.Assume perforated PVC is same prfce as solid i e.- Access Road, R/D D-1 $ 21.00 SY 290 6,090.00 Bollards-fixed D-2 $ 240.74 Each Boliards-removable D-3 $ 452.34 Each '(CBs Inciude frame and lid CB T e i D-4 $ 1,257.64 Each 20 25,152.80 CB T e IL D-5 $ t,433.59 Each CB T e II,48^diameter D-6 $ 2,033.57 Each 13 26,436.41 for additfonal depth over 4' D-7 $ 436.52 FT 25 10,913.00 CB T pe II,54"diameter D-8 $ 2,192.54 Each 3 6,577.62 for addit(onal de th over 4' D-9 $ 486.53 FT t 5 %,297.95 CB T e II,FO"dlameter D-10 $ 2,351.52 Each tor additional depth over 4' D-11 $ 536.54 FT CB T e II,72"diameter D-12 $ 3,212.64 Each for additfonal de th over 4' D-7 3 $ 692.21 FT Throu h-curb Inlet Framework(Add D-14 $ 366.09 Each Cleanout, PVC,4" Q-15 $ 130.55 Each Cleanout,PVC,6" D-i6 $ 174.90 Each 72 12,592.80 Cleanout,PVC,8" D-17 $ 224.19 Each Culvert, PVC,4" D-18 $ 8.64 LF Culvert, PVC,6" D-19 $ 12.60 LF Culvert, PVC, 8" D-20 $ 13.33 LF Culvert, PVC, 12" D-21 $ 21.77 LF Culvert,CMP,8" D-22 $ 17.25 LF Culvert,CMP, 12' D-23 $ 26.45 LF Culvert,CMP, 15" D-24 $ 32.73 LF Culvert,CMP, 18" D-25 $ 37.74 LF Culvert,CMP,24" D-26 $ 53.33 LF Culvert,CMP,30" D-27 $ 71.45 LF CuNert,CMP,36" D-28 $ 112.1 i LF Culvert,CMP,A8` D-29 $ 140.83 LF Culvert,CMP,60' D-30 $ 235.45 LF Culvert,CMP,72' D-31 $ 302.58 LF Page 6 of 9 SUE3TOTAL 82,467.78 12,592.80 Unit prices updated: 02l12/02 'KCC 27A authorizes only one bond reduction. Version: 11/26/OS Site improvement bond quan6ty worksheet.xls Report Date:4/6/2015 � t Site Improvement Bond Quantity Worksheet Webdate: 12/02l2008 Existing Future Public Private Bond Reduction* Right-of-way Right of Way Improvements DRAINAGE CONTINUED &Dra�nage FacUities Quant. No. Unit Price Unit Quant Cost Quani. Cost Quant. Cost Complete Cost Culvert,Concrete,8` D-32 $ 2t.02 LF Culvert,Concrete,12" D-33 $ 30.05 LF Culvcrt,Concrete,15" D-34 $ 37.34 LF Culvert,Concrete,18" D-35 $ 44.51 LF Culvert,Concrete,24" D-36 $ 61.07 LF Culvert,Concrete,30" D-37 $ 104.18 LF Culvert,Concrete,36" D-38 $ 137.63 LF Culvert,Concrete,42" D-39 $ 158.42 LF Culvert,Concrete,48" D-40 $ 175.94 LF Culvert,CPP,6" D-41 $ 10.70 LF 19G� 20972 Culvert,CPP,8" D-42 $ 16.10 LF Culvert.CPP, 12" D-43 $ 20.70 LF 1100 22770 Culvert,CPP, 15" p-44 $ 23.00 LF Culvert,CPP, 18° D-45 $ 27.60 LF 5�0 13800 Culvert,CPP,24" D-46 $ 36.80 LF 390 14352 Culvert,CPP,30" D-47 $ 48.30 LF 460 22218 Culvert,CPP,36" D-48 $ 55.20 LF Ditchin D-49 $ 8.08 CY Flow Dispersal Trench 1,436 base+ D-50 $ 25.99 LF French Drain (3'depth) D-51 $ 22.60 LF Geotextile,laid in trench,pol ro lene D-52 $ 2.40 SY Infiltration ond testin D-53 $ 74.75 HR Mid-tank Access Riser,48"dia, 6'deep D-54 $ 1,6Q5.40 Each Pond Overflow S illway D-55 $ 14.01 SY RestrictodOil Separator,12" D-56 $ 1,045.19 Each Restrictor/Oil Separator,15" D-57 $ 1,095.56 Each Restrictor/Oil Separator,18" D-56 $ 1,146.16 Each 1 1146.1fi Ripra ,placed D-59 $ 39.08 CY 30 1172.4 Tank End Reducer(36"dlameter) D-60 $ 1,000.50 Each Trash Rack,12" D-61 $ 211.97 Each Trash Rack,15" D-62 $ 237.27 Each Trash Rack,18" D-63 $ 268.89 Each Trash Rack,21° D-64 $ 306.84 Each Page 7 of 9 SUBTOTAL 75458.56 20972 Unit prices updated: 02/12/02 'KCC 27A authorizes only one bond reduciion. Version: 11/26/08 Site improvement bond quantity worksheet.xls Report Date:4/6/2015 � , , Web date: 12/02I2008 Site Improvement Bond Quantity Worksheet Exlsting Future Public Private Bond Reductiont R(ght-of-way Right oE Way Improvements &Drainage Facilities Quant. Unit Price Unit Quant. Price Quant. Cost Quant. Cost Complete Cost PARKING LOT SURFACING No. 2°AC,2'top course rock 8�4"borrow PL-i $ 21.00 SY 2"AC, 1.5' to course&2.5'base cour PL-2 $ 28.00 SY 4"select borrow PL-3 � 4.55 SY 1.5"to course rock&2.5°base course PL-4 $ 11.41 SY UTILITY PQLES &STREET LIGHTING Utiliry pole relocation costs must be accompanied by Franchise Utility's Cost Statement Utility Pole(s)Relocation UP-1 Lum Sum 5treet Li ht Poles w/Luminaires UP-2 $ 9,500.00 Each 6 57U00 17 161,500.00 W RITE-IN-ITEMS (Such as detention/water quality vaults.) No. StormFllter Vault WI-1 $65,900.00 Each 1 65,900.00 WI-2 SY WI-3 CY WI-4 LF WI-5 FT wi-s wi-� wi-s wi-s wi-,o SUBTOTAL 57,000.00 227,400.00 SUBTOTAL(SUM ALL PAGES): 163,003.67 599,917.08 191,20128 30%COIVTINGENCY&MOBIIJZATION: 48,901.10 179,375.12 57,360.38 GRANDTOTAL: 211,904.77 779,892.20 248,561.66 COLUMN: B C D E Page 8 of 9 Unit prices updated: 02/12/02 'KCC 27A authorizes only one bond reduction. Version: 71/26/08 Site improvement bond quanGty worksheetxls Report Dato:4/6/207 5 f �� Site Improvement Bond Quantity Worksheet WQbdate: 1?JO?J2008 Original bond computat[ons prepared by: Name: Barry Talkington Date: 2/12/2015 PE Registration Number: 41423 Tel.#: (425) 251-6222 �irm Name: Barghausen Consulting Engineers Address: 18215 72nd Ave S, Kent, WA 98032 Project No: U 14006283 ROAD IMPROVEMENTS&DRAINAGE FACILITIES FINANCIAL GUARANTEk REQUIREMENTS PERFORMANCE BOND" PUBLIC ROAD&DRAINAGE AMOUNT BOND'AMOUNT MAINTENANCE/DEFECT BOND' REQUIRED AT RECORDING OR Stabilization/Erosion Sediment Control (ESG) (A} $ 45,322.2 TEMPORARY OCCUPANCY�" Existing Right-of-Way Improvements (B} $ 211,904.8 Future Public Right of Way&Drainage Facilities (C) $ T/9,8922 Private Improvements (D) $ 248,561.7 Calculated Quantity Completed (E) $ _ Total Right-of Way and/or Site Restoration B�nd"/'* (A+B} $ 257,227.0 (First$7,500 of bond"shall be cash.) Perforrnance Bond"Amount (A+B+C+D) - TOTAL (T) $ 1,285,680.8 T x 0.30 $ 385,704.3 OR MlnimUm bond amount is . Reduced Performance Bond*Total "" (T-E) $ 1,285,680.8 Use larger of x30%or(T-E (B+C)x Maintenance/Defect Bond"Total 0.25- $ 247,949.2 NAME OF PERSON PREPARING BOND"REDUCTION: Date: *NOTE: The word"bond'as used In this document means a financial guarantee acceptable to King County, "NOTE: KCC 27A authorizes right of way and site restoratlon bonds io be combined when both are requlred. 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 minlmum requlrements. 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 remalning after reduction shall not be less than 30%of the original amount(T)or as revfsed by major design changes. � REQUIRED BOND'AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATI�N BY DDES Page 9 of 9 Unit prices updated: 02/12/02 Check ouf ihe DDES Web sffe a! m�w kfng�oun aov/ ermits Version: 11/26/08 Site improvement bond quantiry worksheet.xls Report Date: 4/6/2015 �1 Site Improvement Bond Quantity Worksheet oi/iz/is Original bond computations prepared by: Date: �5 Name: �a!'�Y T0.��..vLq� Tel#: K25 2$I -�ZZ Z � PE Registration NumbeIr: �{ ��{2� Firm Name: �L�(`qV�G.ttSe„^ �0�14)��.w� ��4�y►ee1'S -<�C-. Add�ess: �/s 7�1d �w�- s , [��M T , /.11� !��sZ Project#: (���0���3 ROAD IMPROVEMENTS&DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND* BOND*AMOUNT PUBLIC ROAD&DRAINAGE AMOUNT REQUIRED AT RECORDING MAINTENANCE/DEFECT BOND* OR TEMP OCCUPANCY**# Stabilization/Erosion Sediment Control(ESC) (A) $ 4$,322•2J Existing Right-of-Way Improvments (B) $ Z/l, 9�(.8� Future Public Right-of-Way (C,) $ Sy2� 3�{�i •ZN DrainageFacilities (C2) $ Z37� b93.�8 Private Improvements (D) $ Z��S`1.7c7 Calculated Quantity Completed Total Right-of-Way and/or Site Restoration (A+B)$ 25�-, ZZ� Bond*/•• Performance Bond*Amount(A+B+Cz)x1.5=Tota (T) $ 1`'�l,y bl.`-�� (B+C+Public Portion of C,,)x 0.2 Minimum bond•amount is$2,000 Maintenance/Defect Bond*Tota� _ $ 198�2�9 .'io NAME OF PERSON PREPARING BOND* REDUCTION: DATE: 'NOTE: The word"Bond"as used in this document means a financial guarantee acceptable to the City of Renton. *'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. Required Bond*Amounts Are Subject io Review and Modifications by DDFS. �GHA V� ' m� n� �Z ENGINEER'S ESTIMATE �I, SANITARY SEWER & STREET LIGHTING I _` BOND QUANTITY WORKSHEET � . �,!`t?' I�``Py� ���.. N�trWN Project Name: Coppervuood Date of Estimate: 4/3115 Sfreet Location: SE 2nd PL and 142nd Ave SE BCE Job No.: 16834 Municipality: City of Renton No. of Lots: 47 Developer: Quadrant Homes . . � ITEM DESCRIPTION QTY UNIT UNIT COST TOTAL 8"PVC Pi e sewer i e 72 LF $38.00 $2,736 48"Manhole/T e-1/Saddle Manhole 2 EA $9,600.00 $19,200 Street Li htin lConduiUJunction Box 23 EA $9,500.00 $218,500 � Subtotal $240 436 Total $240 436 � �' TA� , PQ-�` oE W A S y '�� Q> ,`�, , y � � o � Z � � 14 3 �� ��� , �ss� NA LT�E��'\� 04/03l2015 07/15/10 Page 1 of 2 �sa3a.o�a-eQws.�ns I S 9.2 Facility Summary Form � KiNG COUNTY, �TJ.4SHINGTOT�, SURFACE WATER DESIGN 44ANtiAL STORI�ZWATER FACILITY SUN�MARY SHEET DDES Pernut Number (provide one Stormwater Facility Summary Sheet per Natural Discharge Location) �j Overvie�v: Project Name C o�� W��' Date � 1 t t � t S ' Do�vnstream Drainage Basins Major Basin Name �� �;�' Immediate Basin Name M,,���o&- Cncek '�[' ;b�r p3O3 ' Flow Control: Flow Control Facility Name/Number Co�voob2. ��3c�•�:'o� Pon6�. Facility , Location Tr�� 3 If none, Flow control provided in regionaUshared facility (give location) Y1�� No flow control required r J�, Exemption number � 'n��. General Facility Information: Type/Number of detention facilities: T'ype/Number of infiltration facilities: � ponds ponds vaults tanks tanks trenches Control Structure Location T(ti.�� '13 � �3 C�2 1Jork�, S;�.e. o� Qa�a' Type of Control Structure 1��1 ���4'�ce. �-S��'c�� Nlunber of Orifices/Restrictions 2 Size of Orifice/Restriction: No. 1 �. �'a�� � No. 2 3��'' No. 3 No. 4 Flow Control Performance Standard �tiou (,`�„�rr�1 `p�r•a��^ S�o.,���. M��c.4,t„a t'Jf Glt� J'� ����i9nC� 2009 Surface��Vater Design Manual li4/2009 1 K[:VG COUNTY, 1�J�SHiNGTON, SURFACE �VATER DESIG�I MANUAL Live Storage Valume t31� 12. � C. �• Depth �� Volume Factor of Safety ��G Number of Acres Served q. $�A�C Number of Lots 4� Dam Safety Regulations (Washington State Department of Ecology) Reservoir Volume above natural grade 4�,s t 3 C•�� Depth of Reservoir above natural grade �, F�t Facility Summary Sheet Sketch All detention, infiltration and water quality facilities must inciude a detailed sketch. (11"x 17" reduced size plan sheets may be used) 2009 Surface Water Design Manua) 1/9/2009 2 KING COUNTY, WASHINGTON, SURFACE «'ATER DESIGN �4ANUAL i Water Quality: Type/Number of water quality facilitiesBMPs: biafiltration swale sand filter(basic or large) (regular/wet/or continuous inflow) sand filter, linear (basic or , large} combined detentionlwetpond sand filter vault{basic or large) {wetpond portion basic or large) sand bed depth (inches) combined detention/wetvault stormwater wetland filter strip ! storm filter flow dispersion � 6�zL wetpond{basic or large) farm management plan wetvault landscape management plan t�o Is facility Lined? oiUwater separator If so, what marker is used above (baffle or coalescing plate) Liner? catch basin inserts: Manufacturer pre-settling pond pre-settling structure: Manufacturer high flow bypass structure (e.g., flow-splitter catch basin) source contrals Design Information Water Quality design flow 2 . .�� CF$ Water Quality treated volume (sandfilter) ��Vater Quality storage volume («�etpool) � �I`�9 C. F. Facili[y Summary Sheet Sketch 2009 Surface Water Design Manual ]i9/2009 3 KING COUNTY, WASHINGTON, SURFACE ��t�ATER DESIGN \AANUAL � _ All detention, infiltration and water quality facilities must include a detailed sketch. {11"x17" reduced size plan sheets may be used) 20{l9 Surface Water Design Manual l;'9/2009 � - - DRAINAGE FACILITY PLAN AND DETAILS I o � Fofl � 1'-20 co�p,�R wo�� J 6 �0 20 eo f'1"N OF TFiE NWt/4, OF THE SE1/4 OF SEC.15 ���,�ATY�N=i6650 �" aam�ro ca.�i'��sra"`�ucnae TWP. 23 N., RGE 5 EAST, W. M. 'J' CITY OF RENTON, KING COUNIY. STATE OF WASHINGTON \.., ....`-\..-:... ..`. . � � �2'm � ���r�te. ; ��.. `� �`•�''':� � : �.t \\�'. •' ,r''�. � 2a'Mi�E SfANG 7 LF 18�SD O C.SSR i ;�f�:� ' .'�. �+ ORDNU7'f HIGH � �����T � 17;.F f8'SO d 0.555 �.. •;� � '`.�''.� H�TEN 4N7K IC:}7J.7i(187 SECppQApY TdET FEA - � STD 7,.AM 5�ET 26 9�J. '��.'::+.\ `-'•- W/(dFR�P PAD PER C.O.R. SiD#Tkt?34.70 ; '���\.�''�.,`�'. . 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"- _ _ �� _ _ _ ( s�wi�srcaren n oia�a ar nctua '� a corrn�craaror�aw�oEeane+r�xrwsu�riae�rusTr�cwonr�ww�mvrouF*�u�rnEnowia�n L 1'� - - - _] s.aucnnc asnw au�o.s w�o-no� q�i�2s o � �yo — �� � ������ — ccon�rn�crontorrt�u�a�naFN.wte[iw�ivaannswowssFJYuawcrurE � tp p� �,``� X �+�ti, ounn� ��� "Y'r� e cow��ra rorr�iui vqn�ue��iesio�rw��c�wmm�oa�a ��iouw�'antm�wwvs. !�'t�OkAl14`��9 � RDW1R F.CAMfMGTORiOMBIO�Ei1ElIW1iH11QFCOY@MI1rt11T1!{liIB113li0YbROl1�E � \�' �t�, �vnnori � � U ..w�.�r.u��.�w.�w� • � . • �y Z� ? z �„�,,,�,,,�r,^„ t� � y V�/�C� THE STORMWATER MNNAGEMENT STORMFlLTER O �� > �.``.�.�,�... .... ......-.» sx-+-,:�� ���°�� 8'x 14'PEAK DIVERSION STORMFlITER � " �`^ �w.-+..+...r '-��"..: ....� ��•„�-�„-� . - STANDARD DETAIL w �j ar.wes.r+�e�.....w � / .eni.r.e - - - - � � � � a a r.w.v�ls.+�r..� {�Zj N � �7 4CYw�N.wJKAwti. � �€ r ICF+M��YA�IiYr�1 ^Y�� a O fV� C 6���► �N I� s o � �A�w�r�.�.r Z O��O aD �W � m....�..r�e...r. ^ 3�n�n � a w.�r.rwr:me�a•eras�wrr.eer.a ��1�' T �r�.'�r'���+�vo�ou.�w....a.n�.�a.�. �r-�� � E • ts�eW./4r�/�wuisue0�m�r+erMr N Z N N Maw..r.m.r�.Yr.i.�r. �W�� J � Y v v ��n o � I �'8 9 g d � d� E Q1D.PI�M-L77A0 Q � �� pVB1JC itpR16 FLOW RESTRICTOR o z DFP1R[YFM OIL MLLUTION CONTIIOL Z -r / TEB ���� � _ l - aTY oF FiENTON �'b8 ��o"SJ � o��aATn.�nrr oF PUBuc waarca ' � "'�-w" �'�•�•" dl�1 C I T Y 0 F DRAINAGE FACIL(TY DETAL3 ,o�oe/io,. ' �� �'� °" �- �� �I�� RENTON �� � o ,�,�R �. 2 ���*�. � i� �5 �T ;� �UADRANT HOME3 $ 1 REY15fD Ppt CIIY pEY[R Blf 1/15 IS &IT emo w� wNM � � .R�« a,� ,,, «�;, a�o����/eu��,9/wwK waw oev�. 14725 SE 36TH 3T.SINfE 200 �m ,�...�.a. y� �,� a„� ►a. a�s�a+ er nerE ,w�a � I�FI � Fvt1E, WA 98006 A — NNNNAA 9.3 Declaration of Covenant for Impervious Surface Limit To be completed and recorded concurrently with the Final Plat. This note will be removed prior to recording. �� , -_ --���"��:��J:�]�';-,,� RECORDING REQUESTED BY AND WHEN RECORDED MAIL TO: CITY CLERK'S OFFICE CITY OF RENTON 1055 SOUTH GRADY WAY RENTON, WA 98057 DECLARATION OF COVENANT FOR IMPERVIOUS SURFACE LIMIT ��r_ Quadrant Grantee: City of Renton Legal Descriprion:Lots 1 through 47 of the Plat of Copperwood as recorded in Volume_of Plats, pages through_, inclusive, records of King County, Washington (Recording No. ) Additional Legal(s)on: Assessor's Tax Parcel ID#: 152305-9066-03, 152305-9067-02, 152305-9201-09. 152305-9093-00, 152305-9093-83, 152305-9100-01, 152305-9043-01, 152305-9221-05, 152305-9170-06 IN CONSIDERATION of the approved City of Renton construction pemut for application file No. LUA/SWP 14-000550 relaring to real property legally described above,the undersigned as Grantor(s),declares(declare)that the above described property is hereby s established as having a lunit to the amount of unpervious surface allo��ed on the property for tlie purpose of limiting stormwater flows and is subject to the following restriction�. The Grantor(s)hereby covenants(covenant) and agrees(agree) as foltows: no inore than � 65% ��tsr�€eet of impervious surface coverage is allowed on the property. Impervious surface means a hard surface area that either prevents or retards the entry of water into the soil mantle as under natural conditions before development;or that canses water to run off the surface in greater quantities or at an increased rate of flow from the flow present under natural conditions prior to development. Common impervious surfaces include,but are n�t Iimited to,roof, walkways,patios, driveways,parking lots, or storage areas,azeas that are paved, graveled or made of packed or oiled earthen materials, or other surfaces that similarly impede the natural infiltration of surface and storm water. City of Renton or its municipal successors shall have a nonexclusive perpetual access easement on the Property in order to ingress and egress over the Properiy for the sole purposes of inspecting and monitoring the Property's impervious surface coverage. This easemendrestriction is binding upon the Grantor{s}, its heirs, successors, and assigns unless or until a new drainage or site plan is reviewed and approved by the Renton Development Services Division or its successor. � IN WIT�TESS WHEREOF,this Declaration of Covenant is executed this day of , 20 GItANTOR, o��ner of the Property GItANTOR, o���ner af the Property STATE OF �VASHI\GTOV ) COUNTY OF KING )ss. On this day personally appeared before me: ,to me lrnown to be the individual(s}described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their free and voluntary act and deed, for the uses and purposes therein stated. Given under my hand and official seai this day of ,20 Printed name Notary Public in and for the State of Washington, residing at My appointment expires 9 .4 Declaration of Covenant for Inspection and Maintenance of Stormwater Facilities and BMPS 1 ------__-------- ------- To be completed and recorded concurrently with the Final Plat. This note will be removed prior Return Address: to recording. City Clerk's Office City of Renton 1055 S Grady Way Renton,WA 98057 DECLARATION OF COVENANT FOR INSPECTION AND MAINTENANCE OF STORMWATER FACILITIES AND BMPS Grantor: Quadrant Grantee:City of Renton Legal Description:Lots 1 through 47 of the Plat of Copperwood as recorded in Volume of Plats, pages through , inclusive, records of King County, Washington (Rec. No. ) Assessor's Tax Parcel ID#:152305-9066-03. 152305-9067-02. 152305-9201-09. 152305-9093-00. 152305-9093-83, 152305-9100-01, 152305-9043-01, 152305-9221-05, 152305-9170-06 IN CONSIDERATION of the approved City of Renton Constuction permit for application file No.LUAISWP 14-000550 relating to the real property("Property") described above,the Grantor(s),the owner(s)in fee of that Property,hereby covenants(covenant)with the City of Renton, a political subdivision of the state of Washington, that he/she(they)will observe,consent to,and abide by the conditions and obligations set forth and described in Paragraphs 1 through 10 below with regard to the Properly,and hereby grants(grant)an easement as described in Paragraphs 2 and 3. Grantor(s)hereby grants(grant),covenants(covenant),and agrees(agree)as follows: l. The Grantor(s}or his/her(their)successors in interest and assigns("Owners of the described property")shall at their own cost,operate,maintain, and keep in good repair,the Property's stormwater facilities and/or best management practices("BMPs") constructed as required in the approved construction plans and specifications on file with the City of Renton and submitted to the City of Renton for the review and approval of permit(s) U14006283 . The property's stormwater facilities and/or best management practices("BMPs")aze shown and/or listed on Exhibit A.The propeity's stormwater facilities and/or BMPs shall be maintained in compliance with the operation and maintenance schedule included and attached herein as Exhibit B. Stormwater facilities include pipes,swales,tanks,vaults,ponds,and other engineered structures designed to manage and/or treat stormwater on the Property. Stormwater BMPs include dispersion and infiltration devices,native vegetated azeas, permeable pavements,vegetated roofs,rainwater harvesring systems,reduced impervious surface coverage, and other measures designed to reduce the amount of stormwater runoff on the Propetty. 2. City of Renton shall have the right to ingress and egress over those portions of the Property necessary to perform inspections of the stormwater facilities and BMPs and conduct maintenance activities specified in this Declaration of Covenant and in accordance with RMC 46-030. 3. If City of Renton determines that maintenance or repair work is required to be done to any of the stormwater facilities or BMPs,City of Renton shall give notice of the specific maintenance and/or repair work required pursuant to RMC 4-6-030. The City shall also set a reasonable time in which such Page 1 of 3 Fo�m Approved by City Attomey 10/2013 work is to be completed by the O�vners. If the above required maintenance or repair is noi completed within the time set by the City,the City may perform the required maintenance or repair,and hereby is given access to the Property,subject to the exclusion in Pazagraph 2 above, for such purposes. Written notice will be sent to the Owners stating the City's intention to perform such work. This work will not commence until at least seven(�days after such notice is mailed. If,within the sole discretion of the City,there exists an imminent or present danger,the seven(7) day notice period will be waived and maintenance and/or repair work will begin immediately. 4. If at any tune the City of Renton reasonably deternunes that a stormwater facili�or BMP on the Property creates any of the hazazdous conditions listed in RMC 4-4-460 G or relevant municipal successor's codes as applicable and herein incorporated by reference,the Ciiy may take measures specified therein. 5. The Owners shall assume all responsibility for the cost of any maintenance or repair work completed by the City as described in Paragraph 3 or any measures taken by the City to address hazardous conditions as described in Paragraph 4. Such responsibility shall include reimbursement to the City within thirty(30}days of the receipt of the invoice for any such work performed. 4verdue payments will require payment of interest at the current legal rate as liquidated damages. If legal action ensues,the prevailing party is entitled to recover reasonable litigarion costs and attorney's fees. 6, The Owners are hereby required to obtain written approval from City of Renton prior to filling,piping,cutting,or removing vegetation(except in routine landscape maintenance) in open vegetated stormwater facilities(such as swales,channels, ditches,ponds, etc.),or performing any alterarions or modifications to the stormwater facilities and BMPs referenced in this Declaration of Covenant. 7. Any notice or consent required to be given or otherwise provided for by the pmvisions of this Agreement shall be effective upon personal delivery,or three(3) days after mailing by Certified Mait, return receipt requested. 8. With regard to the matters addressed herein,this agreement consritutes the entire agreement between the parties,and supersedes all prior discussions,negotiarions,and all agreements whatsoever whether oral or written. 9. This Declaration of Covenant is intended to protect the value and desirability of the real property described above,and shall inure to the benefit of all the citizens of the City of Renton and its successors and assigns. This Declaration af Covenant shall run with the land and be binding upon Grantor(s),and Grantor's(s') �uccessors in interest, and assigns. 10. This Declaration of Covenant may be terminated by execution of a written agreement by the Owners and the City that is recorded by King County in its real property records. IN WITNESS WHEREOF,this Declaration of Covenant for the Inspection and Maintenance of Stormwater Faciliries and BMI's is executed this day of , 20 GRANTOR, owner of the Properly GRANTOR, owner of the Property Page 2 of 3 Form Approved by City Attorney 10/2013 STATE OF WASHINGTON } COUNTY OF KING }ss. On this day personally appeared before me: to me known to be the individual(s)described in and who executed the within and foregoing instrument and aclrnowledged that they sig�ted the same as their free and voluntary act and deed, for the uses and purposes therein stated. Given under my hand and official seal this day of ,20 Printed aame Notary Public in and for the State of Washington, residing at My appoinhnent expires Page 3 of 3 Form Approved by City Attomey 10/2013 EXHIBIT A Stormpipes and catchbasins in Tracts A, B, and C of the Plat o#Copperwood Combined Detention/Wetpond in Tract 8 of the Plat of Copperwood Contech StormFilter in Tract B of the Plat of Copperwood ,� !_f EXHIBIT B The Copperwood project has a single combined detention/wetpond and a Contech StormFilter vault located within Tract B of the proposed plat. Maintenance of these facilities shall be the responsibility of the individual lot owners within the project development. The onsite conveyance system consists of a series of catch basins and storm pipes which direct stormwater to the drainage facilities within Tract B. Onsite Conveyance Systems within the right of way will be inspected and maintained by the City of Renton. Onsite conveyance systems within the drainage easements or tracts will be maintained by the property owners through the Homeowners' Association created by the subdivision (with each property owner having equal responsibility for maintenance). These conveyance elements include those entering and exiting the tract from/to the public right-of-way. For conveyance pipes entering the tract from right-of-way, responsibility begins at the last structure prior to entering the tract. For conveyance pipes exiting the tract to right-of-way, responsibility ends at the next downstream structure. The easement shall grant the City rights for inspection. Maintenance of the above listed stormwater facilities shall be conducted on an annual basis. For more information or to obtain a copy of the Maintenance Manual please reference Section 10.0 of the Technical Information Report for the Plat of Copperwood on record with the City of Renton. �._ � l 10.0 OPERATIONS AND MAINTENANCE MANUA� The Copperwood project has a single combined detention/wetpond and a Contech StormFilter vault located within Tract B of the proposed piat. Maintenance of these facilities shall be the responsibility of the individual lot owners within the project development. The onsite conveyance system consists of a series of catch basins and storm pipes which direct stormwater to the drainage facilities within Tract B. Onsite Conveyance Systems within the right of way will be inspected and maintained by the City of Renton. Onsite conveyance systems within the drainage easements or tracts will be maintained by the property owners through the Homeowners' Association created by the subdivision (with each property owner having equal responsibility for maintenance). These conveyance elements include those entering and exiting the tract from/to the public right-of-way. For conveyance pipes entering the tract from right-of-way, responsibility begins at the last structure prior to entering the tract. For conveyance pipes exiting the tract to right-of-way, responsibility ends at the next downstream structure. The easement shall grant the _ City rights for inspection. Maintenance of the above listed stormwater facilities shall be conducted on an annual basis. Please refer to the maintenance requirements within this section. _ , , I i �� � I � ` i , � 16834.015.doc APPENDIX A f44AI'vTENA�tCE REQUIREI�4E�IT5 FLOW CONTROL,CO�IVEYANCE,A;�ID�VQ FACILITIES NO. '1 - DETENTI4N PONDS Maintenance Defecf or Probtem Conditions When Mainfenance!s 13eeded Results Expected When Component Maintenance Es Performed Site Trash and debris Any trash and debris which exceed 1 cubic foot Trash and debris c�eared from site. per 1,040 square feet(this is about equal to the amount of trash it would take to fifl up one standard size office garbage can). In general, there should be no visual evidence of dumping. Noxious weeds Any noxious or nuisance vegetaUon which may Noxious and nuisance vegefation constitute a hazard to County personnet or the removed according to appiicable public. regulations. No danger of noxious vegeiation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of potlution as oiE,gasofine,concrete slurries or paint. according to applicable regufations. Source contro!BMPs implemented if appropriate. No confaminants present oiher than a surFace oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a I height. height no greater than 6 inches. Top or Side Slopes Rodent holes Any evidence of rodent holes if facilily is acting Rodenfs removed or destroyed and of Dam,Berm or as a dam or berm,or any evidence of water dam or berm repaired. Embankment piping through dam or berm via rodent holes. Tree growth Tree growth threatens integrity of slopes,does Trees do not hinder facility not allow maintenance access,or interferes with performance or maintenance maintenance activity. If trees are no#a#�reat or activi6es. not interfering with access or maintenance,they do not need to be removed, Erosion Eroded damage over 2 inches deep where cause Slopes stabilized�sirtg appropriate of damage is still present or where there is erosion conUol measures. If erosion potential for continued erosion. Any erosion is axurring on compacted slope,a observed on a compacted sfope. licensed avil engineer shou(d be consulfed to resolve source of erosion. Setflement Any part of a dam,berm or embankment that has Top or side slope restored ta design serited 4 inches lower than the design elevation. dimensions. If settlemenf is significant,a licensed civil engineer should be consulted to determine the cause of the settlement Storage Area Sediment Accumulated sediment that exceeds 10%of the Sediment cleaned out to designed accurnulation designed pond depth, pond shape and depth;pond reseeded if necessary to control erosion. Liner damagec! �iner is visible or pond does not hold water as Liner repaired or replaced. (!f Applicable) designed. lnletlOutlet Pipe. Sediment Sediment filling 20°to or more of the pipe. InleUoutlet pipes clear of sediment. accumulaBon Trash and debris Trash and debris accumulated in inleUoudet No trash or debris in pipes. pipes{includes floatables and non-ftoatables). Damaged Cracks wider than'/rinch at the joint of the No cracks more than Y,-in�wide at inleUouUet pipes or any evidence of soif entering the joint ot the inleUoutlet pipe. at the joints of the inleUouElet pipes. Emergency Tree growth Tree growth impedes flow or threatens stability of Trees removed. OverFlow/Spillway spillway. Rock missing Only one 3ayer of rock exists above native soil in Spiilway rastored to design area five square feet or larger or any exposure oi standards. native soil on the spill�vay. 1/9/20o9 2009 Surface Water Design Manual—Appendix A p_� APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOVV CONTROL,CONVEYANCE,AND tNQ FACILITIES NO.4-CONTROL STRUCTUREIFlOW RESTRICTOR Maintenance Defec#or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance Is Per#ormed Structure Trash and debris Trash or debris of more than'/:cubic faot vrhich fVo Trash or debris blocking or is located immediately in front of the structure potentially blocking entrance to opening or is blocking capacity of the structure by structure. more than 10%. Trash or debris in the structure that exceeds'13 No trash or debris in the structure. the depth from the bottom of basin to invert the lowest pipe into or out of the basin. Deposits of garbage exceeding 1 cubic foot in No condition presenf which would �oluma. atfract or support the breeding of insects or rodents. Sediment Sediment exceeds 60°Jo of the depth from the Sump of strucfure contains no bottom of fhe structure to the invert of the lowest sediment. pipe into or out o#the slruc#ure or the bottom of fhe FROP-T section or is within 6 inches of the invert of the lowest pipe info or out of fhe strvcture or the bottom of the FRQP-T section. Damage to frame Corner of frame extends more than'/.incn past Frame is even with curb. andlor top slab curb face into the street(if applicable). Top slab has hales larger than 2 square inches or Top slab is free of holes and cracks. cracks wide�than'/,inch. Frama not sitting flusfi on top slab,i.e., Frame is sitting flush on top slab. separation of more than 3/,inch of the frame from the top slab. Cracks in wails or Cracks wider than Y:inch and longer than 3 feet, Structure is sealed and sfructurally bottom any evidence of soil particles entering structure sound. through cracks,or maintenance person judges that structure is unsound. Cracks wider than Yx inch and longer than 1 foot No cracks more fhan'/a inch wide at at the joint of any inleUoutlet pipe or any evidence the joint of infeUoutlet pipe. of soil particles entering structure through cracks. Settlement/ Structure has settled more than 1 inch or has Basin replaced or repaired to design misalignmenf rotated more fhan 2 inches out of atignment. standards. Damaged pipe joints Cracks wider than%:-inch at the joint of the No cracks more than Y.-inch wida at inletloutlet pipes or any evidence of soil entering the joint of inleVoutlet pipes. the structure at the joint of the inleVouHet pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and dlsposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminanfs present other than a surfaca oil film. Ladder rungs missing Ladder is unsafe due to missing rungs, Ladder meets design standards and or unsafe misalignment,rust,cracks,or sharp edges. allows maintenance person safe access. FROP-T Section Damage T section is not securely aftached to structure T section securely attached to walf wall and outlet pipe structure should support at and outlet pipe. least 1,000 Ibs of up or down pressure. Siructure is not in upright position(allow up to S#ructure in correct position. 10°!o from plumb). Connections to outlet pipe are not watertight or Connections to ouBet pipe are wafer show signs of deteriorated grout. tight;structure repaired or replaced and works as designed. Any hotes—ofher than designed holes—in the Sfructure has no holes other than structure. designed holes. Cleanout Gate Damaged or missing Cleanouf gafe is missing. Replace cleanout gate. ?�fl9 Surface Water Design Manual—Appendix A 1!9/2009 A-7 APPENDIX A MAINTENAl�CE REQUIREMENTS FLO��V CONTROL,CONVEYANCE,AtvD WQ FACILiTIES NO.4-CONTROL STRUCTUREIFLOW RESTRICTOR Maintenance Defect o�Problem Condition When Maintenance is Needed Results ExpecEed When , Component Maintenance is Performed Cleanout gata is not watertight. Gate is watertight and worlcs as designed. Gate cannot be moved up and down by one Gafe moves up and down easily and maintenance person. is watertight. Chain/rad leading to gate is missing or damaged. Chain is in place and works as designed. Orifice Ptate Damaged or missing Control device is not working properly due to Plate is in place and works as missing,out of place,or Bent orifice plafe. designed. Obstructions Any trash,debris,sediment,or vegetation Plate is free of all obstructions and blocking ihe plate. works as designed. Overflow Pipe Obstructions Any trash or debris blocking{or having the Pipe'ss free of all obsfructions and potential of blocking}the overfiow pipe. works as designed. Deformed or damaged Lip of overflow pipe is bent or deformed. Overflow pipe does not allow lip overflow at an elevation lower than design Inief/Outlet Pipe Sediment Sediment filiing 209�0 or more of the pipe. InleUouttet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleVoutlet IVo trash or debris in pipes. pipes{includes fioatables and non-floatables}. Damaged Cracks wider than Y�-�nch at the joint of the No cracks more than%.-inch wide at inleUouBet pipes or any evidence of sail entering the joint of the intetloutlet pipe. at the joints of the inleUoutlet pipes. Metal Grates Unsafe grate opening Grate with opening tvider than'!P inch. Grate opening meets design (If Applfcablaj standards. Trash and debris Trash and debris tha#is blocking more than 2Q% Grate free of trash and debris. of grate surface. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s)o#the grate. Grate is in place and meets design standards. Manhole CoverlLid Cover/lid not in place Co�edlid is missing or only paRlally in place. Covedlid protects opening to My open structure requires urgent structure. maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper toals. Not Worlcing maintenance person with proper tools.Bolts cannot be seated. Self-locking coverllid does not work. Covedlid difficult to One maintenance person cannot remove Covertlid can be removed and Remove coverllid after applying 84 Ibs.of lift. reinstalled by one maintenance person. 1/9/2pp9 2009 Surface Vdater Design Manual—Appendix A A-8 APPENDiX A MAINTENANCE REQUIREMEVTS FOR FLOW CONTROL,CONVEYANCE,Ai�1D VJQ FACfLITIES NO. 5-CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Ezpected When Component Maintenance is Performed Structure Sediment Sediment exceeds 60%of the depth from the 5ump of catch basin contains no bottom of the catch basin to the invert of the sediment. fowest pipe fnto or out of the catch basin or is within 6 incftes of the invert of the lowest pipe into or out of the catch basin. Trash and debris Trash or debris of more than'/:cubic foot which No Trash or debris blocking or is located immediately in front of the catch basin pofendally blocking enVance to opening or is blocking capacity of the catch basin catch basin. by more than 10%. Trash or debris in the catch basin that exceeds No trash or debris in the catch basin. '/3 the depfh from the bottom of basin to invert the lowest pipe info or out of the basin. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within catch basin. gases(e.g.,methane). Depasits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Damage to frame Comer of frame extends more than'/.inch past Frame ls even with curb. andlor top slab curb face info the sL�eet{If applicable). Top slab has holes larger than 2 square Inches or Top slab is free of holes and cracks. cracks wider than Y.inch. Frame not sitting ftush on top slab,i.e., Frame is sitting flush on top slab. separation of more than%.inch of the frame from the top slab. Cracks in waI(s or Cracks wider than Y�inch and longer than 3 feet, Catch basin is sealed and bottom any evidence of soif particles entering catch structuralty sound. basin through cracks,or malntenance person judges that catch basin is unsound. Cracks wider than'/z inch and longer than 1 foot No cracks more than�/,inch wide at at the joint of any infeVoutlet pipe or any evidence the joint of inleUoutlet pipe. of soil partides entering catch basin through cracks. SetUemenV Catch basin has settled more than 1 inch or has Basin repEaced or repaired to design misalignment rotated more than 2 inches out of alignment. standards. Damaged pipe joints Cracks wider than Yzinch at the joint of the No cracks more than Y.-inch wide at inleUoutiet pipes or any evidence of soil entering the joint of inleUoutlet pipes. the catch basin at the joint of tt�e inlet/outlet pipes. Contaminants and Any evidence of contaminants or pollutlon such Materials removed and disposed o# pollutlon as oil,gasoline,concrete slurries or paini. according to applicable regulations. Source control BMPs implemented if appropriate. �fo contaminants present other than a surface oil film. 1nIeU0utlet Pipe Sediment Sediment flling 20�0 or more of the pipe. InleUoutlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleVoutlet No trash or debris in pipes. pipes(indudes floatables and non-floatables}. Damaged Cracks wider than%:-inch at ifie joint of tMe No cracks more than'/.-inch wide at infet/outlef pipes or any evidence of soil entering the Joint of the inleUoutlet pipe. at thejoints of tfie inleUoutlet pipes. 2009 Surface Water Desigt�?Vlanual—Appendix A 1/4.-2009 A-9 APPENDIX .4 MAINTENANCE REQL"IREMENTS FLOW CONTROL,COIVVEYANCE,A1�D WQ FACILITIES NO. 5-CATCH BASINS AND MANHOLES ��, Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When I Component Maintenance is Performed Metal Grates Unsafe grate opening Grate with opening wider than'!g inch. Grate opening meets design (Catch Basins) sfandards. Trash and debris Trash and debris that is blocking more than 20% Grate free of trash and debris. of grate surface. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s)of the grafe. Grate is in place and meets design My open structure requires urgent standards. ma3ntenance. Manhole Cover/Lid Co�er/lid�ot in place Cover(lid is missing or only partially in place. Cover/lid protects opening to Any open structure requires urgent structure. maintenance. Locking mechanism Mechanism cannot be openad by one Mechanism opens with proper tools. Not Working maintenance person with proper tools.Botts cannot be seated. Self-locking covedlid dces not work. Covediid d�cult to One maintenance person cannat remove CoveNlid can be removed and Remove coveNlid after applying 80 Ibs.of I'rft. reinstalied by one maintenance person. ,_ } � !�'91?009 2009 Surface VVater Design�Vfanual—Appendix A A-10 APPE�IDI�A MAINTENANCE REQUIREA�9ENTS FOR FLOW CONTROL,COI�VEYANCE,AND WQ FACILITIES NO. 6-CONVEYANCE PIPES AND DITCHES Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When ', Component Maintenance is Performed i Pipes Sediment 8 debris Accumulafed sediment or debris that exceeds Water flows freely through pipes. ' accumulation 20°/a of the diameter of the pipe. VegetaboNroots Vegetation/roots that reduce free movement of Water flows freely through pipes. water through pipes. Contaminants and Any evidence of conlaminants or pollution such Materials removed and disposed of potlution as oil,gasoline,concrete slurries or paint. according to appiicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a sutface oil film. Damage to proteclive Protective coating is damaged;rust or corrosion Pipe repaired or replaced. coating or corrosion is weakening the structural integrity of any part of pipe. pamaged Any dent that decreases the cross section area of Pipe repaired or replaced. pipe by more than 20%or is detennined to have weakened structural fntegrity of the pipe. Ditches Trash and debris Trash and debris exceeds 1 cubic toot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumutated sediment that exceeds 20%of the Ditch cleanedlflushed of all sediment accumulation design depth. and debris so that it matches design. Nozious weeds Any noxious or nuisance vegetation which may Idoxious and nuisance vegetation constifute a hazard to County personnel or the removed according to app)icable public. reguladons. No danger of noxious vegetation where County personnel or the public might nortnally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concxete sturries or paint. according to appiicable regula6ons. Source controf BAAPs implemented if appropriate. No contaminants present other than a surtace oil film. Vegetation Vegetation that reduces free movement of water Water flows freely through ditches. through ditches. Erosion damage to Any erosion observed on a ditch slope. Slopes are not eroding. slopes Rock lining out of One layer or less of rock exists above nabve soii Replace rocks to design standards. place or missing(If area 5 square feet or more,any exposed nadve Applicable) soil. I � I�I 2009 Surface Water Design Manual—Appendix A 1 r9:20(l9 A-11 APPENDIX A 'vtAII�TENANCE REQUIREMEI�TS FLOW CONTROL,CONVEYANCE,AND\�1Q FACILITIES , NO. 7- DEBRIS BARRIERS (E.G., TRASH RACKS) ' Maintenance Defect or Problem Condition When Matntenance is Needed Results Expected VYhen Component �Aaintenance is Performed. Site Trash and debris Trash or debris plugging more than 20%of the Barrier dear to receive capacity flow. area of the barrier. Sediment Sediment accumulation of greater than 20%of Barrier clear to receive capacity flow. accumulation the area of the barrier Structure Cracked broken or Structure which bars attached to is damaged- Structure bartier attached to is loose pipe is loose or cracked or concrete structure is sound. cracked,broken of loose. Bars Bar spacing Bar spacing exceeds 6 inches. Bars have at most 6 inche spadng. Damaged or missing Bars are bent out of shape more than 3 inches. Bars in place vrith no bends more bars than'/.inch. II 8ars are missing or entire barrier missing. Bars in place according to design. 'I Bars are loose and rust is causing 50% Repair or replace barrier to design � deterioration to any part of barrier. standards. ' 1;9/2009 2009 Surface Water Design ti4anual—Appendix A � A-12 APPEtiDIX A A4AINTENANCE REQUIRE\4EI�TS FLOW CONTROL,COtitiEYA�CL,AND 1VQ FACILI7"1ES I, NO. 9- FENCING I Maintenance Defect o�Problem Conditions When Maintenance is IVeeded Resulfs Expected When Component Mafntenance is PerFormed Site Erosion or holes Erosion or holes more than 4 inches high and 12- No access under the fence. under fence 18 inches wide permitting access through an opening under a fence. Wood Posts, Boards Missing or damaged Missing or broken boards,posY out of plumb by No gaps on fence due to missing or and Cross Members parts more than 6 inches or cross members broken broken boards,post plumb to within 1'/:inches,cross members sound. Weakened by rotting Any part showing structural deterioration due to All parts of fence are structuralfy or insects rotting or insect damage sound. Damaged or failed Concrete or metal attachments deteriorated or Post foundation capable of ! post foundation unable to support posts. supporting posts even in strong I wind. I Metal Posts,Rai(s Damaged parts Post out of plumb more than 6 inches. Posf pfumb to within 1'/:inches. II and Fabric ' Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence(including post,top rails,and Fence is aligned and meets design fabric)more than 1 foot out of design alignment. standards. Missing or loose fension wire. Tension wire in place and holding fabric. Deteriorated paint or Part or parts that have a rusting or scafing Structurally adequate posts or parts protective coating condition that has affected siructural adequacy. with a unHorm protective coating. Openings in fabric Openings in fabric are such that an 8-inch Fabric mesh openings within 50°10 of diameter ball could frt through. grid size. � 1/9;2009 2009 Surface Water Design Manual—Appendix A A-14 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLO�V COi�TROL,CONVEYANCE,AND WQ FACILITIES N0. 10-GATES/BOLLARDSIACCESS BARRIERS • Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Pertortned Chain Link Fencing Damaged or missing Missing gate. Gates in place. Gate members Broken or missing hinges such that gate cannot Hinges intact and lubed.Gate is be easily opened and ciosed by a maintenance working freely. person. Gate is out of plumb more than 6 inches and Gate is aligned and vertical. more than 1 foot out of design alignment. Missing s#retcher bar,stretche�bands,and ties. Stretcher bar,bands,and Nes in place. Locking mechanism Locking device missing,no-functioning or does Locking mechanism prevents does not lock gate not link to all parts. opening of gate. Openings in fabric Openings in fabric are such that an 8-inch Fabric mesh openings within 50%of diameter ball could fit through. grid size. Bar Gate Damaged or missing Cross bar does not swing open or closed,is Cross bar swings fully open and cross bar missing or is bent to where it does not prevent closed and prevents vehicle access. vehicle access. Locking mechanism Locking device missing,no-functioning or does Locking mechanism prevents does not lock gate not link to all parts. opening of gate. Support post Support post does not hold cross bar up. Cross bar held up preventing vehicie , damaged access into facility. � Boliards Damaged or missing Ballard broken,missing,does not fit into support No access for motorized�ehicles to ; hole or hinge broken or missing. get into facility. does not lock Locking assembly or lock missing or cannot be tJo access far motor+zed vehicles to j aftached to lock bollard in pface. get fnEo facility. Boulders Oislodged Baulders not located to prevent motorized vehicle No access for motorized vehicles to � access. get info facility. { Circumvented Motorized vehicles going around or between No access for motorized vehicles to I boufders. get into facility. � 2009 Surface��'ater Desigit'�fanuat—Appendix A I r'9i2009 A-1� APPENDtX A MAINTENANCE REQUIREA4ENTS FLOR'CO:VTROL,CONVEYANCE,AND VVQ FACILITIES N0. 11 -GROUNDS (LANDSCAPING) AAaintenance Defect or Probtem Conditions When Maintenance is Needed Results Expected When Gomponent Mafn#enance is Performed Site Trash or litter Any trash and debris which exceed 1 cubic foot Trash and debris cleared from sife. per 1,000 square feet(this is about equal to the amount of trash it wouid take io fil!up one standard size offce garbage can). In generai, there should be no visual evidence of dumping. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation cons6tute a hazard to County personnel or the removed according to appfica6le public. regulations. No danger of noxious vegetation where Counry personnel or the pubiic might normaily be. Contaminants and Any evidence of con#aminants or polluBon such hAaterials removed and disposed of pollution as oil,gasoline,concrete sturries or paint. accarding to applicable regulations. Source control BMPs implemented if appropriate. fVo contaminants present oiher than a surface oil film. Grasslgroundcover Grass or groundcover exceeds 18 inches in Grass or groundcove�mowed ta a height. height no greater than 6 inches. Trees and Shrubs Hazard Any tree or limb of a tree idsntified as having a No hazard trees in facili#y. pofential to fali and cause property damage or threaten human life. A hazard tree identified 6y a qualif(ed arbortst musE be removed as soon as possibte. Damaged Limbs or parts of trees or shrubs that are sp{it o� Trees and shrubs with less than 5°!0 broken which affect more than 25°�of the to#al of totaf foliage with split or braken foliage of the tree or shrub. limbs. Trees or shrubs that have bee�blown down or No blown do�vn vegetation or knocked over. knocked over vegetation. 7rees or shrubs free of injury. Trees or shrubs which are not adequately Tree or shrub in place and supported ar are leaning over,causing exposure adequately supported;dead or of the roots. diseased trees removed. 1/9/20U9 2009 Surface Water Design ylanual—Appendix A A-I 6 APPENDIX A 1�4AINTENANCE REQUIRE�IENTS FOR FLOW CONTROL,CONVEYANCE,A:�ID WQ FACILITIES N0. 12-ACCESS ROADS Maintenance Defect or Problem Conditian When Maintenance(s Needed Results Expected When , Component Maintenance is Performed I Site Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway drivable by maintenance square feet(i.e.,trash and debns would fill up vehlGes. one standards size garbage cart). Debris vrhich could damage vehicle tires or Roadway drivabie by maintenance prohibit use of road. vehicles. Contaminants and My evidence of contaminants or polfution such Materials removed and disposed of pollution as oil,gasoline,concreta slurries or paint. according to applicable regufations. Source controi BMPs implemenfed if appropriate. No contaminants present other than a surface oif film. Blodced roadway Any o6struction which reduces clearance above Roadway overhead ciear to 14 feet road surface to less than 14 feet. high. I Any obstruction restricting the access to a 10-to At least 12-foot of width on access ' 12 foot width for a distance of more than 12 feet road. or any point restricting access to less than a 10 foot width. Road Surtace Erosion,settlement, Any surface defect which hinders or prevents Road drivable by maintenance potholss,soft spots, maintenance access. vehicles. ruts Vegetation on road Trees or other vegetation prevent access to Maintenance vehicles can access surface facility by maintenance vehicles. facility. Shoulders and Erosion Erosion within 1 foot of the roadway more than 8 Shoulder free of erosion and Ditches inches wide and 6 inches deep. mafching the surrounding road. Weeds and brush Weeds and brust►exceed 18 inches in height or Weeds and brush cut to 2 inches in hinder maintenance access. height or cleared in such a way as to allow maintenance access. Modular Grid Contaminan#s and Any evidence of contaminanfs or pollution such Materials removed and disposed of Pavement pollution as oil,gasoline,ooncrete slurries or paint. according to applicable reguia6ons. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damaged or missing Access surface compacted because of broken on Access road sur#ace restored so missing modufar block. road infiftrates. 2009 Surface Water Design Manual—Appendix A 1/9i?009 I A-17 � .APPENDIX:'� A1AIT�TET�AI�CE RFQUIRE�IENTS FOR FI.OW COi�TROL,CONVEYA\CE,AND\'4'Q FACILITIES N0. 16-WETPOND Maintenance Defect or Problem Cond(tlon When Mafntenance is Needed Results Expected When Component Maintenance Is Performed - Site Trash and debris Any trash and debris accumulated on the Wetpond site free of any trash or wetpond site. debris. Noxious weeds Any noxious or nuisance vegetation which may IJoxious and nuisance vegetation constitute a hazard fo County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of poliution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Side Slopes of dam, Rodent holes Any evidence of rodent holes if facility is acfing Rodents removed or destroyed and Berm,intemal berm as a dam or berm,or any evidence of water dam or berm repaired. or Embankment piping through dam or berm via rodent holes. Tree growth Tree growfh threatens integrity of dams,berms or Trees do not hinder facility slopes,does not allow maintenance access,or performance or maintenance interferes with maintenance activity. If trees are activitles. not a threat to dam,berm or embankment integrrty,are not interfering with access or maintenance or leaves do not cause a plugging problem they do not need to be removed. _ Erosion Eroded damage over 2 inches deep where cause Slopes stabilized using appropriate of damage is still present or where there is erosion control measures. If erosion potential for continued eroslon. Any erosion is occurring on compacted slope,a observed on a compacted slope. licensed civil engineer should be consulted to resolve source of erosion. Top or Side Slopes Settlement Any part of a dam,berm or embankment that has Top or side sfope restored to design of Dam,Berm, settfed 4 inches lower than the design eleva8on. dimensions. If settlement is intemal berm or significant,a licensed clvil engineer Embankment should be consulted to determine the cause of the settlement. Irregular surface on Top of berm not un'rform and level. Top of berm graded to design internal berm elevation. Pond Areas Sediment Accumulated sediment that exceeds 10°Ja of the Sediment cleaned out to designed _ accumulation(except designed pond depth. pond shape and depth. first wetpool celf) Sediment Sediment accumulatfons in pond boriom that Sediment storage contains no accumulation(first exceeds tiie depth of sediment storage{1 foot) sediment. wetpool cell) p(us 6 Inches. � Liner damaged(lf Llner is visible or pond does not hold water as Liner repaired or replaced. Applicab(e) designed. Water level(first First cell empty,doesn't hold water. Water retained in first cell for most of wetpool cell) the year. Algae mats(first Algae mats develop over more than 10%of the Algae mats removed(usually in the wetpool ce(I) water surface should be removed. late summer before Fall rains, especialiy in Sensilive Lake Protection Areas.) Gravity Drain Inoperable valve Valve wilE not open and close. Valve opens and closes normalty. Valve won't seal Valve does not seal completely. Valve completely seals closed. Emergency Overflow Tree grovvth Tree growth impedes flow or threafens stability of Trees removed. Spillway spillway. 2009 Surface Water Design Manual—Appendix A 1/9/2009 A-21 APPC-NDIX A MAIVTENANCE REQL'IRE�IENTS FLOW CONTROL,CONVEYAT�lCE,AND WQ FACILITIES N0. 16-WETPOND I Maintenance Defect or Problem Conditfon When Maintenance is Needed Results Expected When Component Maintenance Is Performed Rock missing OnEy ona layer of rock exists above native soil in Spillway restored to design area five square feet or larger,or any exposure of standards. native soil at the top of out flow path of spillway. Ri�rap on inside slopes need not be replaced. I InIeVOutlet Pipe Sediment Sediment filling 20%a or more of the pipe. InfeUoutlet pipes dear of sediment. I! accumulation ' Trash and debris Trash and debris accumulafed in inleUoudet t�o trash or debris in pipes. ' pipes(includes floatables and non-floatables). Damaged Cracks wider than'/:-inch at the joint of the No cracks more than Y.-inch wide at inletloutlet pipes or any evidence of soil entering the�oint of the inletloutlet pipe. at the joints of the inleUoutlet pipes. r I,`912�09 2009 Surface Water Design Manual-Appendix A A-22 �, APPENDIX A MAINTENAI`CE REQL'IREMENTS FLOW CONTROL,CONVEYANCG,AND WQ FACILITIES � NO. 21 -STORMFILTER(CARTRIdGE TYPE) Maintenance Defect or Problem Condition When Maintenance is Needed Results E�cpected When ' r Component Maintenance is Performed � 1 : ' Site Trash and debris Any trash or debris which impairs the function of Trash and debris removed from ' the facility. facility. Confaminants and Any evidence of contaminants or pol(ution such Materials removed and disposed of pollution as oils,gasoline,concsete slurries or paint. according to agplicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil fifm. L'rfe cycle System has not been inspected for three years. Facility is re-inspected and any needed maintenance performed_ Vault Treatment Sedimenl on vault Greater than 2 inches of sediment. Vau1t is free of sediment. Area ftoor Sediment on top of Greater than'/�inch of sediment. Vauft is free of sediment. cartridges Nlultiple scum lines Thick or multiple scum lines above top of Cause of pfugging corrected, above top of cartridges. Probabiy due io piugged canisters or canisters replaced if necessary. cartridges underdrain manifold. Vauft Structure Damage io wall, Cracks wider than'/�-inch and any evidence of Vault replaced or repaired to design Frame,Bottom,andlor soil partides entering the structure through the spec�cations. Top Slab cracics,or qualified inspection personnel determines the vault is not structurally sound. Baffles damaged Baffles corroding,cracking warping,and(or Repair or replace baffles to showing signs of faifure as determined by specification. maintenanceCnspection person. Fifter Media Standing water ln 9 inches or greater of static water in the vault for No standing water in vauR 24 hours vault more than 24 hours foliowing a rain event and/or after a rain event. overfto�v occurs frequently. Probably due fo " plugged fi{ter medla,underdrain or outlet pipe. Short circuiting Flows do not properly enter filter cartridges_ Flows go through filter media. Underdrains and SedimenUdebris Underdrains or clean-outs paRially plugged or Underdrains and clean-0uts fres ot Clean-Outs filted�vith sediment and/or debris. sediment and debris. lnleUOutlet Pipe 5ediment Sediment filling 20%or more of the pipe. InleUoutlei pipes clear of sediment. accumulation Trash and debris Trash and debris accumufated in infet/outlet No trash or debris in pipes. pipes(includes floatables and non-ftoatables). Damaged Cracks wider than'/2-inch at fhe joint of the No cradcs more than Y.-inch wide at __ inleUoutfet pipes or any evidence of soil entering the joint of the inleUouUet pipe. at the joints of the inlet/oudet pipes. Access Manhole Coverllid not in place Cover/lid is missing or only partially in place. Manhole access covered. Any open manhole requires immediate maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. not working maintenance person with proper toofs.Bot#s cannot be seated. Self-locicing coverllid does not work. CoverRid difficult to One maintenance person cannot remove Coverllid can be removed and remove cover/lid after applying 80 Ibs of lift. reinstalled by one maintenance person. Ladder rungs unsafe Mlssing rungs,misalignment,rust,or cracks. Ladder meets design standards. Allows maintenance person safe axess. Large access Damaged or difficuft Large access doors or plates cannof be Rep(ace or repair access door so if doorslplate to open opened/removed using normal equipmenL can opened as designed. ', 1;9.�'009 ?009 Surface Water Desien i�?anaal—:'lppendix A A-30 V I ���i����A� ���►��' ■ .�5� CONSTRUCiION PRODUCiS INC. � � StormFilter Inspection and Nlaintenance Procedures ; , ... ; . :_, �� F ' f � , �,:. 71�e Seotmwaler Management �tormFiiter�� Maintenance Guidelines In addition to these two activities,it is important to check The primary purpose of the Stom�water Management the condition of the StormFilter unit after major storms for a, potential damage caused by high(Iows and for high sediment StormFilter is to filter out and prevent pollutants from entering accumulation that may be caused by localized erosion in ihe our watervvays.Like any effective 6ltration system,periodically dralnage area.It may be necessary to adjust the inspecdoN these pollutants must be removed to restore the StormFilter to its maintenance schedule depending on the actual operating " � full efficiency and effectiveness, conditions encountered by the system. In general,inspectfon Maintenance requirements and frequency are dependent on the adivibes can be conducted at anytime,and maintenance should pollutant toad characteristics of each site. Maintenance activities occur,if warrantetl,in late summer to earty fall when flows into ' may be required in the event of a chemical spill or due to the system are not likely to he present. excessive sediment loading from site erosion or extreme storms.lt is a good practice to inspect the system after majorstorm events. Malll'�eYlaI1C@ Fr@[,U@I1CS/ The p�imary factor controlling timing of maintenance of the Maintenance Procedures StormFilter ls sediment loading. Although there a�e likely many effective maintenance q properly functloning system will remove solids from water by options, we believe the following procedure is efflcient and trappfng particulates ln the porous stn.idure of the filter media '� can be implemented using common equipment and exlsting ��slde the cartridges.The flow through the system will naturally � mai ntenance protornts. A two step procedure is recommended decrease as more and more particulates are trapped.Eventually as follows: the flow through the cactridges will be low enough to require 1. (nspectiot� replacement.It may be possible to extend the usable span of the Inspection of the vault interior to determine the need for �nridges by removing sediment from upstream trapping devices maintenance. on a routine as-needed basis In order to prevent material from � being re-suspended and discharged to the Storm�ilter treatment 2. Maintenance system. Cartridge replacement Sediment remova) Site conditions greatly influence malntenance requirements. Storm�ilter units located in areas with erosion or active Inspeetion and Maintenanee Timing construction may need to be inspected and maintained more At least one scheduled inspection should take place per year with often than those with fully stabilized surface conditions. maintenance following as warranted. The maintenance frequency may be adjus#ed as additional I } First, an inspection shoufd be done before the winter season. monitoring informatlon becomes available during the inspection � � During the inspectton the need for maintenance should be Progrem.Areas that dev�lop k�own problems should be determined and, if disposal during maintenance will be required, Inspected more ftequently than areas that demonstrate no � samples of the accumulated sediments and med(a should be problems,parttcularly after major storms.Ultimately,inspection - obtained. and maintenance activities should be scheduted based on the hlstoric records and characteristics of an(ndividual5tormHlter Second,if warranted,a maintenance(replacement of the filter rystem or site. It is recommended that the site owner develop cartridges and remova)of accumulated sedlments)should be a database to properly manage StormFf(ter inspectlon and performed during perlods of dry weather. maintenance programs. Pr(or to the development of the maintenance database,the following maintenance frequencfes should be followed: tnspectlon �f_ One time per year � After maJor storms F Maintenance _ As needed,based on results of InspectEon(The average maintenance Iffecyde is approxlmate(y 1-3 years) f;, --�_� Per Regulatory requirement In the event of a chemical spill ', � Frequencies should be updated as required,The recommended � ��Y � � ��'�?. ''' .- ;�' :. '� � ; inidal frequency for inspection is one time per year,StormRlter . ��'"�f�--''�`�'� ' ' '`-=�;4,s ' units should be inspected after major storms. � � �� -�_��� - r. . �, ._L✓;�,1 .� ,�` . . �e n_ y� ��;.r;'�,�' ���'==.ti'� _ _ _ ��. Sediment removal a�d cartridge replacement on an as needed 7.Remove safety equipment. basis ts recommended unless site conditions warrant. 8.If appropriate, make notes about ihe local drainage area Onte an understand'mg of site characte�tstics has 6een re�ative to ongoing constnution,erosion probl�ns,or high " • established, maintenance may not be needed for one to three loading of otF►er materiais to the system. - years,but inspedion is warranted and recommended annualiy. 9.Discuss conditions that wggest ma(ntenance and make � decision as to weather or not maintenance is needed. Inspecfiion Procedures Maintenance Decision lree The primary goal of an inspecdon(s to assess the condition of The need for maintenance is typicaUy based on rewlts of the the cartridges relative to the leVel of visual sediment(oading as inspection. The following Maintenance Dedsion Tree shouW be used as it relates to decreased treatment capacity.It may be desirable to a general guide. (Other facton,such as Regulatory Requirements,may conduct this inspection during a riorm to observe the relative need to be considered) #!ow through the filter cartridges.If the wbmerged cartridges FQ- .� are severely plugged�then typkally large amounts of sediments y� • will be present and very IKtle flow will be discftarged from the drainage pipes,if thfs is the case,then maintenance is warranted � and the cartridges need to be replaced, Warning:in the case of a spill,the worker should abort � � Inspection activides until the proper guidance Is obtained. Notify the local hazard mntrol agency and COMECH construcdon Products immediately. To condudan fnspection: Important: Inspection should be performed by a person who , is famiHarwilh the operadon and configuration of the StormFilter treatment unit. 1. If appflcable,set up safety equipment to protect and notify surrounding vehide and pedesti-ian traffia , 2.Visuaily inspect the external condition of the unit and take 1.Sediment loading on the vauh floor. • nofes cohcerning defecEs/problerns. a. If>4"of accumulated sediment, rnaintenance is requfred. 2.Sedtment loading on top of the cartridge. �; � a. If>1/4"of accumulatbn,maintenance is rec�ired. t;r1.: ' 3.SuUmerged cartridges. },'Yti:i�.'ty�t' .- �;'; ,:�1�.:si��,� ��� - a. If>4"of static water in the cartridge bay for more ?Ifr`-t� �'�r,,`�h�'���o=i.� �;;.> �'�__,�,�. , ,�. , t�, that 24 hours after end of ra(n event�ma(ntenartce is _ , , ��� L_ p,;!'�,�,�•3''f:���;,:r_ ,... a �_�, � �t��^�r�r ; .,-� required. ��;���.�,����;��- - ,� -� _ 4.Plugged media. a. !f pore space between media granules is absent, a;��;' '''� ' ' maintenance is required. � f•. a�"` -e ,..�, �•,.. �'�,�.w,�',u�..4.,,-3:—' —`� - 5.Bypass mndition. � � .tr• F�:°;• • �.( a. If inspection is conducted during an average tain fall S1;9�✓�4. � �� �I���:• x.� ;., ev�nt and StormFdter remains in bypass condidon ��b i1 ���F�,�'�,,,��. (water over the intemal ou�et baffle wail w wbmerged �i*i'.�,�;�,��`'�,��"�i��,.l��.��i `��- . cartridges),maintenance is required. it�,ti d•, r,��'. 1 .t.�J;�.r:•t� � 3.Open the access portals to the vault and allow the system vent. 6.Hazarclous material release. 4.Witfiout enteting the vault,vfsually(nspect the instde of the a. If hazardous mate�fal re{ease(automotive fluids w other) unit,and note accumulations of liqulds and solids. ts teported,maintenanoe is required. 5,Be sure to record the(evel of sediment build-up on the floor of 7,pronounced scum line. the vault, In the forebay�and on top of the cartrldges.If tlow a. If pronounced sam line(say�z 1/4"thlcW ls present � is occurr(ng,-note the flow of water per drainage pipe.Record above top cap,maintenance is required. all observattons.Digital plctures are valuable for historical documentat(on, 8.Calendar lifec�tcle. 6.Close and fasten the access portals. a. If system Mas not been maintained for 3 years maintenance Is required. — Assumptions • No rai�fall for 24 hours or more ' „ •� • No upstream detention(at least not drain(ng Into StormFilter) � • Structure Is online , � • Outlet pipe is dear of obstruction �,� ;.� - • Construction bypass ts plugged � � { ,i., Main#enance - Depending on the configuration of the particular system, malntenance personnel wtl!be required to enter the vault to perform the matntenance. Importan�If vault entry is requited,OSHA rules for confined ' I space entry must be followred. ���� Filter cartridge replacement should occur durtng dry weather. • ''� it may be necessary to plug the filter inlet pipe ff base flows is o�currmg. �4 � ��; Replac�nent cartridges can be delivered to tl�e site or customers �_,: �� ' faality.Infiormation conceming how to obtain the replacemeni � '�,�r1��ti: '•y "� ;"' ; , cartridges is available from CONTECH Construction Products. � p��-i-' '�� ' '� '� '` l� Warning;in the case of a spitl,ihe maintenance personnel ` , shauld abort maintenance aciivities until the proper ' guidance is obtained. Notify the loca)hazard control �� agency and CONTECH Construction Products immediately. � ' To conduct cartridge replacement and sediment removal � -� maintenance: Important:Note that cartridges containing leaf inedia(CSF)do 1.If applicable,set up safety equipment to protect maintenance not require unscrewing from their connectors.i'ake care personnel and pedestrians from site hazards, not to damage the manifold connedors.This connector '+` 2.�sually inspect the extemal condition of the unit and take should remain installed in the manifold and could be notes concerning defecWproblems. capped during the maintenance adivity to prevent sediments from entering ihe underdrain manifold. 3.Open the doors(access portals)to the vauit and allow the - system to vent B. Remove the used cartridges(up to 250 lbs.each)irom the 4.Without entering the vault,give the inside of the unit, vault. induding components,a general condition in�et8on. Impor#ant:Care must be used to avoid damaging the 5.Make notes aboutthe extema!and internal condition of cartridges during removal and installation.The cost of � the vault G'tve pa�ticular attention to recording the level of repairing components damaged during maintenance sediment build-up on the floor of the vault,in the forebay, will be the responsibility of the owner unless CONTECH and on top of the intemal components. Construction Products performs the maintenance activities 6.Using appropriate equipment offload the replacement and damage is not related to discharges to the system. carbidges(up to 150 Ibs.each)and set aside. C. Set the used cartridge aslde or load onto the hauling A-_ 7.Remove used ca�tridges from the vault using one of the truck. following methodr. D. Continue steps a through c until all cattridges have been Method 1: removed. A. This activity will requ'ire that maintenance personnel enter I the vault to remove the cartridges from the under dra(n �ethod 2: manifold a�d place them under the vault opening for A. Enter the vault using appropriate mntined space lifting(removan• Unscrew(rnunterc}ocktn►1se rotations) protocols. eacfi filter cartridge from the underdrain connector. g. Unscrew the cartridge cap. Roll the loose cartridge,on edge,to a convenient spot beneath the vauk aceess. C. R�nove the�rtridge hood saews(3)hood and float. . , Using appropriate Ftioist�ng equipment,attach a cable D. At location undet shucture aaess,tfp the cartridge on its from the boorn,crane,or tripod to the loose cart�ldge. �ide, -. Contact CONT'EEH Construction Products for wgg�ted attachment de+sces_ lmportant:Note that cartridges containing media other than the(eaf inedia require unstrewing f�om their threaded connectors.Take care not to damage the manifold connectors.This connector should remai�installed in the manifold and capped if necessary, i D. Empty the cartridge onto the vauit floor.Reassemble the I' empty cartridge. _ __ � ��'_ . �. ,��1 . , E. Set the empty,used cartrEdge aside or load onto the - -- , hauling truck. ~'--�-: - � .� -���.w � ��� '� ��' F Continue steps a through e until all cartridges have been . _;� ���_� , removed. _ ,:a=. _ . _� � �' �'; - � - /� , �� � - -. `� r—' � ��' �`, -r , . - � • .. :s, . . � '�... i �� _ _ �, •`��+;�.'�.,�, {,, • t:ro � �..�' �1 ;�,Y .r '� :t`.4 T: :,t ' .• ___-��f _,•�. ,;� ,1•'�y}-j� ' -._,-�. -- �:'C_"�-�7r., c-+. } � �;' -�� .•^�-�- _.� _':_��� `;`:.� •�►:.z�-�.:_��i`-it'44.�',�.; :1 �T; .0 *�':'r:i `F�r.'�� p S `:1'l�. .k. .��'•L � ��a � -'a�• � ,�- �t�:'s-`~ � �..���^V��� li �. ' �. ` I'�' J..������~S•_%:.-Vt������' .� -r� '?tr_•,£;._'C.�, -��� •.t r:y�...,,yP -- F,: ��: ,,: :j.:�� - '� .c';,'`' e.- - >r;�}� �f l}, �:� A .,` '... __, - , _'< .�_ '�, .,j - 8. Remove accumutated se�liment from the fioor of the � vault and from the forebay.This can most effectivefy be „ � accompfished by use of a vacuum trudc, ,r � , 9. Once the sediments are removed,assess the condition of the , _�'= - �y ' ��`��;;-; ' vault and the conditton of the connectors,The connectors - - - � - are short sections of 2-inch schedule 40 PVC,or threaded -' - -'� ', _. schedule 80 PVC that should protrude aUout 1"above the - ��f� floor of the vault lightly wesh down the vault int�tor. a. Replace any damaged connectors. 10. Using the vawum truck boom,crane,or tripod,lower and instalf the new cartridges.Once again,take care not to damage rnnnections. 11.Close and fast�the door. 12.Remove safety equlpment. 13. �inally�dispose of the accumulated materials in accordance • . _'" wid�applicable regulations.Make arrangements to�etum ihe used emntv cartridges to CONTECH Construction Products. � Rela�ed Mairntenante Ac�tiviti�s - Material Disposaf Pet-�armed on an as needed basis 7he accumulated sed'�mentfound in stormwater treatment StormFilter units are often just one of many siructures in a more and conveyance systems must be handled and disposed of in comprehetts(ve stormwater dratnage artd treatrnent system. acwrdance with regu(atory protomfs.It is possib;e for seditnents . to contain measurable concentrations of heavy rrtetals and ." in order for malntenance of the StormFiiter ta be suaessful,it organic chemicals{su�h as pesticides and petroteum products). is imperathre that all ofiher components be properiy mafntalned. qreas with the greatest pabential#or high poliutant loading The maintenance/xepair of upstream fac+tities should be carr(ed �n�lude industrial areas and heavil�travefed roads. out prior to StormFiFt2r ma(ntenance activittes. 5edfinents and water must be ctisposed of in accordence with tn additlon to consldering upstream facilities,It fs also important all applicable waste dksposal regula�ons.When schedufing to carrect any Probfems identified In the drainage area. Drainage m���tepance,consideretlon must he made for the disposa!of area concems may indude:erasian pro6lems,heavy oi1 loading, solld and I(quid wastes,Tf�is typically requites coordination with and discharges of inappropriate materials. a 1a�a�tanclfil)for sotld warte disposal. F�r Ilquid waste disposal a number of options are avaiEable inctuding a municipal vacuurn truck decant facilitK local waste water treatment p[ant or on-site treatment and discharge. �b�PAPE� . t� `�♦ � soHsi�uc o eao�nnmsix's. soa.��s.i�zz tvtiraw con#ech-cpl.com SuppOrt � Drawings and speci�ications are avaitabl�at contechstormwafier:com. • SEte-specific design suppott is avaifabl�#rom our engineers. ��009 CONTECt�i ConstrucEion Produc#s(ttc. CONI'ECH Consti-uction Proc�ucts 1nc.provides slte soluHons for ths cf�rif engineering indus�COMECN's portfollo includes brldges,drainage,sanitary sewer,stormwater and eerth stabif(zatton products, For information on otfier CON1'ECH divlsion ofhetings,visit coRtech-cPi•rom or caf18Q0,�38,1122 �fotl�ing in th3s catalog shauld be construed as an expressed warrenty or an Implisd warranty of inerchantabNity or fitness for -. . anyr p�rticuisr purpose,see the coM�ECH standard quotation or�cknowiedgement for applicable warranties and other terms anc#condi#ions of sale. Tfie prodvctW desv8�ad may be protated by one or more of tM toQov+tng US pateMs: s,92Z,629;3,6�;57Q 5,707,5Z7;5,759,d15;5,78D,848;5,985,157:6,OZ7,639;8,350,37A;6,405,218; 6,64t,72D:6,571,54$6,649.046;6.981,118;6,999,036:7,186,OSd;ref�ed fofdpn patents or othor}+nten[s pen�ng. i I � • ° 0 'I' � Date: Personnel: . I Location: System 5ize: � 5ystem Type: Va�lc❑ Cast tn-Piace ❑ I.Inear Cafch Basin ❑ Manhole ❑ O�ttter ❑ � SedimerttThiclmess in Forebay. Date: 5ediment i7epth on Vauit Floor. � 5tructural Damage: ' I Esdm�ted Flow from Dralnaqe Pipes('t�available}: � { Cartridges Submerged: Yes ❑ f�o ❑ De.pth of Standing Water. � Stori'r�Fi(ter Maintenance Activities(check off if done and give descrfptian} ' ❑ '[�ash and Deb�is Removal: � ❑ Minor St�c#ural Repairs: , � brainage Area Report � Excessive Oi1 Load€ng: Yes � No � Source: - __ � 5ediment Accumu�ation on Pavement; Yes � No � Soutce: Eraslon of Candscaped Areas `(es ❑ No �] Source: � ftems(Veeding Furtfler WoriG � Dwrters sf�outd coniacC the loca!p�tWic werks department and inquire about how tt�e departmenE dlsposes of their stre�t waste residuals. � other�omments: . f � I I . i f I � � I i f f � i � � � J . '', ! . f � � Review ihe condition feports fron�the prFvious inspeckon visits. � o . ' e � , t Date; Personnel• ( f • � I Location: SysYem 5iz�: � System Type: Vault❑ Cast En-Place❑ �fnear Catch Basin ❑ Manho(e ❑ Other ❑ I List Safe#y Procedures and�qraipmem Used: , � i � � Syst�m Observations � Mohtfis in Serv�ce: Oi!It►Forebay: Yes ❑ IVo � � 5ediment Depth in Farebay: , � Sediment Depth on Vaul#Hoor, , Structural!]amage: 43rainage Area Report � Excessive Oil Loading: Yes ❑ t�o ❑ 5ource: � Sedlment Acntmulation on Pavemen� Yes ❑ Na ❑ Saua're: I Erosion of t.andscaped Areas: YeS ❑ No [� 5ouree: I - StormFiiter Cartriclge Replacemenf Mairrtenante Acti+tlfi�s I Remove Tcash anci Debri�: Yes ❑ tJo ❑ Detalls; � Replaee Cartridges: Yes ❑ Na � Retafls; � Sediment Removed: Yes ❑ No � Details: � 'I Quantity of Sediment Removed{estimate7): . 1 . 'I Minor 5tructural�Repairs: Yes � iVo � Details: i � Reslduals{debris,sedimen�?Disposet Methads: I I Notes; , � � 1 l � I � �� ( ( . i Appendix A Lower Cedar River Basin ! and Nonpoint Pollution Action Plan Watershed Management Committee Lower Cedar River Basin and Nonpoint Pollution Action Plan �. ` P : I 'i '•� - I . � r, �� ~}� �� �(�� ♦ �4 � � �l / j ` � ��..'. .. l�f ' �. t �� 'Y '�r • 1� a��F 4 •.. � �>'" •; '�=a �ti � � � A �' `s;. '-i, �,� ,r� ., . � .. ; �i /r . �� i � ,� ����� - S />� � } x I /t - -.l �� I �' r. i .c�, {• ' �^`/,�I� � § � -'" +�* t.�� 3�::t, ,, i -- i a��� ,. t,,ta� ` i -- �- `� �`� , �� � � �� .�1��. , . t 1 t.`�; ,,� . C �t �' �;:; 1. • � ► � '��`''*.' � t '`', �..'• . • � . , �` � � �� t��e � . � ;.s.�."„ �,,. �' _.+.� . .� , ; � � y'� � . '� � �"� �� j. ,"� `r �,:-= =a �� ., r �4��r _ . _ �_��•—`:,�.� � �� .� ., � � �, y ���z. � . , t� , �,�, > , � ��� I • � �f' ti�� • \ -�'` " � .a. • . # . t t-. yq t � f 1 ,� � ,f �� , . , I.� . '- a 4 . .� , , , . � � ✓x ��,��. . �, �.. }t� ,,. . < �. 1 �,. . � , ,�:. -�., � � . � � �` � � , , \ •}� +� ;� � \� � � ,e �,� > ,, __ :�` �''� �" � r �.- � �` �' '�j — ,�.' � ,i�k�.' ,'�; � � '� � � ._ :, i�=-z ���� �_ r� __ . 0 WASHINGTON STATE •� ' O KING COu�TY �D E P A A T M E N T 0 F .� . �Department of Natural Resources �E C 0 L 0 G Y 'N Watershed Management Committee Lower Cedar R.iver Basin and Nonpoint Pollution Action Plan Adopted by Metropolitan King County Council July 1997 July 1998 Printing ', '' King County Department of Natural Resources Cedar River Watershed Management Committee Water and Land Resources Division City of Renton 700 Fifth Avenue King Conservation District Suite 2200 King County Seattle,Washington 98104 Muckieshoot Indian Tribe (206)296-6519 Seattle Public Utilities Department Trout Unlimited United States Army Corps of Engineers Washington Department of Fish and Wildlife Washington Department of Nahzral Resources Washington Department of Transportation Washington Farm Forestry Association Funded in part by the 6Yashington State Departmen!of Ecolog��Centemzinl Clean bYater Ftnul King County Esecutive Gary Locke Metropolitan King County Conncil Waspington Department of Ecology Maggi Fimia,District I Bob�uffy,Environmental Planner Cynthia Sullivan,District 2 Kitty Gillespie,Project Manager Louise Miller,District 3 Larry Phillips,District 4 WaEershed Management Cammittee Ron Sims,District 5 David Beedle and Leslie Groce-Muckleshoot Indian Rob McKenna,District 6 � Tribe Pete von Reichbauer,District 7 Paul Crane—Boeing Company Greg Nickels,District$ Nancy Davidson,P.E. - Seattle Public Utilities Kent Pullen,District 9 Jack Davis-King Conservation District Larry Gossett,District 10 Gary Engman and Bob Gerke-WA Department of Jane Hague,District 1 I Fish and Wildlife Brian Derdowski,District 12 Keith Hinman-King County WLRD Christopher Vance,District 13 Kay Johnson-Renton Chamber of Commerce (retired),Cedar River CAC Department of Natural Resources Louis Kahn-Washington Farm Forestery Associarion Pam Bissonnette,Director Linda Smith-US Army Corps of Engineers Ron Straka,P.E.-City of Renton Surface Water Utility Water and Land Resources Division Rex Thompson-WA Dept.of Natural Resources Nancy Hansen,Division Manager Frank Urabeck,P.E. -Trout Untimited Debbie Arima,Assistant Division Manager Bob Winter,P.E. - WA Dept.of Transportation Bili Eckel,Regional Water Resources Services Manager Citizen Advisory Commiftee 'I Mike Balasa � Contributing Staff Norm Bunkowski II Keith Hinman,Basin Planning Program Manager Judith Fillips ; Roz Glasser,Project Manager Ray Griffin Jean White,Project Manager Brad Habenicht I John Adams,Planner Janice Hoon(deceased) Derek Booth,Ph.D.,Geologist Kay 7ohnson Glenn Evans,P.E.,Senior Engineer Bob Karinen David Hartley,P.E.,Ph.D.,Hydrologist Laure Iddings Gino Lucchetti,Senior Ecologist Ed Matthews Kate Rhoads, Senior Water Quaiity Specialist Paul Szewczykowski Ruth Schaefer, Senior Ecologist Technical Advisors Supporting Staff Carolyn Boatsman-City of Renton Fred Bentler,Planning Support Technician Mike Bonoff,Rand Little,and George Schneider- Anne Bikle,Basin Steward Seattle Public Utilities Department Rika Cecil,Resource Planner Larry Fisher and Hal Michael-Washington Karen Goto,P.E.,Senior Engineer Deparhnent of Fish and Wildlife Mary Jorgensen,Resource Planner Johnathan Frodge,Ph.D. -King County Department of • Ted Krause,Planning Support Technician Natural Resources,Wastewater Treatment Division Mark Lampard,P.E.,Engineer Dan Harvey,P.E.-US Army Corps of Engineers Barbara Nelson,Technical`Vriter David Jennings,P.E.-City of Renton Laurel Preston,Graphic Technician Greg Zentner-Muckleshoot Indian Tribe Bill Priest,Ecological Technician David Rigley,Engineer Rran Solomon,Ph.D., Senior Engineer Text ivill be rnade available in large print, Braille, or Ruoxi Zhang,Planning Graphic Supervisor audiotape as requested. WMC Lower Cedar River Basin Plan ii Table of Contents Page Listof Figures and Tables............................................................................................................v ExecutiveSummary.....................................................................................................................vii Chapter 1: Introduction to the Cedar River Basin and Nonpoint Pollution Action Plan.......1-1 The Major Conditions in the Cedar River Basin ...................................................................1-1 The Major Plan Recommendations........................................................................................1-5 TheBasin Planning Area.......................................................................................................1-8 Aboutthe Plan Itself..............................................................................................................1-15 Chapter 2: Goals and Priority Actions...................................................................................2-1 Introduction............................................................................................................................2-1 Flood-Damage Reduction......................................................................................................2-4 Aquatic Habitat Protection and Restoration ..........................................................................2-11 Protection of Water Quality from Nonpoint Source Pollution..............................................2-16 AquiferProtection..................................................................................................................2-20 ~ Cedar River Watershed Management Program .......................2-23 .............................................. Relationship of Chapter 2 to Chapters 3 and 4......................................................................2-24 Chapter 3: Subarea Recommendations..................................................................................3-1 Introdu ct i on............................................................................................................................3-1 CedarRiver Mainstem...........................................................................................................3-5 NorthernTributaries...............................................................................................................3-17 SouthernTributaries...............................................................................................................3-27 � Taylor Creek .......................................3-37 , ................................................................................... PetersonCreek.......................................................................................................................3-43 MiddleTributaries .................................................................................................................3-49 RockCreek.............................................................................................................................3-55 Chapter 4: Detailed Descriptions of Recommendations........................................................4-1 Introduction............................. .4-1 ' .............................................................................................. Capital Improvement Projects................................................................................................4-3 Basinwide Recommendations................................................................................................4-31 Subarea Programmatic Recommendations............................................................................4-83 Chapter 5: Implementation Strategy......................................................................................5-1 ' Introduction............................................................................................................................5-1 Priority Setting: Balancing Competing Needs.......................................................................5-1 Sharing Implementation Roles............................................ ...................................................5-5 Implementation Process: Long-Term Watershed Management ............................................5-10 iii Table of Cortte�rts _, j i, 1 i Appendix A: WMC Vision, Goals, and Objectives...................................................................A-1 PlanVision Statement............................................................................................................A-1 Goalsand Objectives.............................................................................................................A-1 Appendix B: Addendum to Bedload Transport Analysis..........................................................A-9 Appendix C: Hydrology and Forest Retention..........................................................................A-11 Technical Note 1: Upland Flooding and Channel Stability...................................................A-11 Technical Note 2: Downstream Analysis Peterson, Rock, and Taylor Creek Ravines........A-19 Appendix D: Significant Resource Area Map, Definitions, and List........................................A-29 Definitions..............................................................................................................................A-29 Si nificant Resource Areas SRAs ..........................................................A-30 g ( ............................ Appendix E: Estimation of Salmonid Production Potential and Costs of Fish Habitat Restoration Opportunities................................................................................................A-35 ExecutiveSummary...............................................................................................................A-35 Introduction............................................................................................................................A-3 8 Background............................................................................................................................A-39 Methods..................................................................................................................................A-42 Results....................................................................................................................................A-55 Discussion..............................................................................................................................A-58 Conclusions............................................................................................................................A-65 Acknowledgments..................................................................................................................A-66 LiteratureCited......................................................................................................................A-66 List of Tables and Figures......................................................................................................A-69 Cedar River Habitat Opportunity Concept Reports...............................................................A-89 , Bibliography ................................................................................................................................A-145 II'� � List of Acronyms 'I 63;�11C Lower Cedar•River Basi�i Plart iv List of Figures and Tables Page Figure 1-1 Cedar River Drainage Basin...................................................................................1-3 Figure 1-2 Current Land Use/Land Caver................................................................................1-11 Figure 1-3 Future Land Use/Land Cover..................................................................................1-13 Figure 3-1 Subarea Boundaries ................................................................................................3-3 Figure 3-2 Cedar River Mainstem Reach 1 ..............................................................................3-11 Figure 3-3 Cedar River Mainstem Reach 2..............................................................................3-13 Figure 3-4 Cedar River Mainstem Reach 3..............................................................................3-15 Figure 3-5 Maplewaod and Orting Hill Subbasins...................................................................3-21 Figure 3-6 Cedar Grove Subbasin ............................................................................................3-23 Figure 3-7 Cedar Hills and Webster Lake Subbasins...............................................................3-25 Figure 3-8 Ginger Creek Subbasin...........................................................................................3-31 Figure 3-9 Molasses Creek Subbasin .......................................................................................3-33 Figure 3-10 Madsen Creek and Summerfield Subbasins ...........................................................3-35 Figure 3-11 Taylor Creek Subarea.............................................................................................3-41 Figure 3-12 Peterson Creek Subarea..........................................................................................3-47 Figure 3-13 Middle Tributaries Subarea.....................................................................................3-53 Figure 3-14 Rock Creek Subarea............................................................................................:...3-59 Figure 4-1 Renton Urban Growth Area....................................................................................4-63 Figure 4-2 Tributary R/D Standards for New Development....................................................4-73 Figure 5-1 Comparison of Core Plan Costs - Mainstem vs. Tributary Areas...........................5-6 Figure 5-2 Comparison of Core Plan Costs - Habitat vs. Water Quality .................................5-7 � Figure 5-3 Comparison of Core Plan Costs - CIPs vs. Program Recommendations................5-S Figure C-1 Flow Benefits of Forest Protection (Till Soil Site, High Runoffl...........................A-16 Figure C-2 Flow Benefits of Forest Protection (Till Soil Site, Low Runof� ...........................A-17 Figure C-3 Flow Benefits of Forest Protection (Outwash Soil Site).........................................A-18 Figure C-4 Erosion Potential in Taylor Creek Ravine, Catchment TS Outlet ..........................A-24 Figure C-5 Erosion Potential in Taylor Creek Ravine, Catchment T2 Outlet ..........................A-25 Figure C-6 Erosion Potential of Flows Downstream of Peterson Lake....................................A-26 Figure C-7 Erosion Potential in Lower Rock Creek.................................................................A-27 Figure D-1 Significant Resource Area Map..............................................................................A-33 Figure E-1 Pre-Project Coho and Cutthroat Smolt Production Potential as a Function of StreamGradient......................................................................................................A-88 � Figures and Tables Tabie 2-1 Where to Find Chapter 2 Recommendations in Chapters 3 and 4..........................2-26 Table 4-1 Priorities for Open Space Acquisitions...................................................................4-38 Table 4-2 Cedar Open Space,�Mitigation Banking, and Restoration Sites .............................4-42 Table 4-3 Tributary R/D Requirements.......................... .........................................................4-71 Table 5-1 Cedar River Basin Plan Recommendations............................................................5-14 Table 5-2 Other Surface and Groundwater Management Activities in the Cedar River Basin........................................................:..............................................................5-20 Table B-1 Cedar River Sediment Data(Revised)....................................................................A-10 Table E-1 General Physical Data for the Cedar River Basin...................................................A-70 Table E-2 Stream Channels Accessible to Anadromous Salmonids in the Lower Cedar RiverBasin..............................................................................................................A-70 Table E-3 Biological Performance Values Used for�stimating Salmonid Production Potential of Cedar River Habitat Projects...............................................................A-71 Table E-4 Fish Production Data and Values Used for Estimating Range of Fish Production...............................................................................................................A-72 Table E-5 Reported Literature Values for Egg-to-Fry Survival Rates and Female Spawner Densities for Sockeye and Chum Salmon................................................A-73 Table E-6 Project Description and Habitat Dimensians for Cedar River Habitat Opportunities...........................................................................................................A-74 Table E-7 Amount of Salmonid Habitat From Habitat Projects in the Lower Cedar RiverBasin..............................................................................................................A-78 Table E-8 Annual Production Potential of Juvenile Salmonids from Habitat Projects in ' the Lower Cedar River.............................. ..............................................................A-79 Table E-9 Annual Production Potential of Individual Habitat Projects in the Lower CedarRiver.............................................................................................................A-80 Table E-10 Long-Term Costs and Salmonid Production Potential for Habitat Projects in the Lower Cedar River............................................................................................A-82 Table E-11 Land Ownership and Risk of Lost Opportunity of Lower Cedar River HabitatProjects.......................................................................................................A-84 Table E-12 Number of Spawners Needed to Achieve Juvenile Production Estimates .............A-87 if�MC Lotinel•Cedar�River•Basin Plan vi Executive Summary The Cedar River Basin and Nanpoint Pollution Action Plan describes the condition of the basin and proposes solutions to the problems of flooding and declining salmon and steelhead runs. It also recommends preventive measures to protect water quality, groundwater supplies, and habitat as the basin planning area continues to develop. Preventing problems in the watershed will be much more cost-effective over time than trying to correct problems once they occur. The recommendations in the Cedar River Basin Plan have been prioritized into a Core Plan consisting of capital projects and ongoing administration of programs that would, at a minimum, accomplish the Plan's most important goals. This Core Plan would: • Resolve the threat of hazardous flooding for approximately 90 percent of the 130 homes currently at greatest risk; • Protect the most valuable remaining aquatic habitat sites in the basin planning area, restore those with the best chance for recovery, and help ensure long-term productivity of Lake Washington salmon and steelhead; and • Maintain the Cedar River's high water quality. i The Cedar River Basin Plan offers a unique opportunity and challenge to meet the needs of urban and rural residents living in the Cedar River basin, and to provide for reduced itood damages and long-term, self-sustaining fish runs. The Cedar River Basin Plan combines a traditional King County Basin Plan,jointly funded by King County and the City of Renton,with a Nonpoint Source Pollution Action Plan funded by the Washington Department of Ecology and called for by the Puget Sound Water Quality , Management Plan. The Basin Plan was prepared under the poIicy direction of the Cedar River Watershed Management Committee, composed of representatives of local and state gor�ernment agencies, the Muckleshoot Indian Tribe, and non-governmentat organizations. A Citizens Advisory Committee, made up of area residents, also contributed to the develapment of the Plan. King County's Water and Land Resources Division(formerly Surface Water Management Division) acted as lead in plan preparation. THE BASIN PLANNING AREA The Cedar River is one of five major rivers in King County and is the largest tributary to Lake Washington. The river drains an elongated basin of 188 square miles that extends westward from the crest of the Cascades to the southem shore of Lake Washington in the City of Renton. The upper basin, which is almost exclusively owned by the City of Seattle, supplies drinking water for two-thirds of the City of Seattle and its regional customers, It is an unpopulated mountainous area protected from land use change and managed for long-term forestry and wildlife Ilabitat. vii Executive Siunma�y i The Cedar River Basin Plan focuses on the lower third of the basin where floods and erosion directly impact people and property, and where ongoing development threatens aquatic habitat and the quality and quantity of ground and surface waters. The basin planning area extends from the Landsburg Dam ta the river mouth in Renton, a 66-square mile area encompassing both the northern and southern plateaus and the mainstem valley. The lower basin has an extensive surface water system that includes 15 named tributaries, many high-value wetlands, lakes, and the Cedaz River itself. W,A�1C Lower Cedar River Basrn Plan viii � Northern Tributaries INTRODUCTION The Northern Tributaries subarea is composed of the subbasins of Maplewood Creek and the Orting Hill, Cedar Grove, Cedar Hills, and Webster Lake tributaries. They all display the three-part profile typical of the western portion of the basin planning area, originating on the gently sloping plateau above the Cedar River, dropping through steep ravines cut into the valley wall, and finally flowing across the low-gradient valley floor to meet the Cedar River. Land use is mostly residential, and is generally densest in the west, changing gradually from urban in the Maplewood Creek subbasin to relatively rural in the Webster Lake area. Maplewood Creek and the Orting Hill and Cedar Grove tributaries are inside the urban growth boundary, so most future growth is expected to be concentrated here. Local drainage problems and minor flooding are fairly common on the poorly drained plateau during larger storms, but hazardous flooding has not been a serious concern here in the past, nor � is it expected to be in the future. In addition to the expected loss of aquatic habitat through encroachment or outright displacement of wetland and stream area by development, some of the undeveloped ravines in this subarea � have experienced the loss of previously high-quality habitat as increases in stormwater runoff � ' have accelerated natural rates of erosion and mass wasting. The resulting sediment reduces the flow capacity of the channels, causing flooding and impacting habitat still further. Water quality in the Northern Tributaries is currently impacted by land development. In the western portion, within the proposed urban growth boundary, development is expected to intensify, fizrther increasing pollutant loadings associated with urbanization—such as road drainage, household hazardous wastes,pesticides, and herbicides. In addition, areas within the Maplewood Creek subbasin have also experienced higher than average septic system failures. Still, of the entire basin planning area, the East Renton Plateau, which is inside the urban growth boundary and has relatively low-density development, is best suited to higher intensity land uses. This is because it has the lowest resource value of any area in the basin, and it lacks tne high quality aquatic resource values that still remain outside the urban growth boundary. If higher density is to be accommodated in this subarea, however, measures such as those that follow will be needed to protect the City of Renton's sole-source aquifer, protect and restore and the remaining wetland and stream resources, and reduce current and projected drainage problems, while allowing available land to be used most efficiently in the future. In addition, any proposal for density changes would require a comprehensive plan amendment involving an environmental review and opportunity for public comment and approval by the City or County council, as appropriate. The Basin Plan's principal capital recommendation for this subarea would reduce flooding in the j Puget Colony Homes subdivision and erosion in Maplewood Creek ravine. Several additional capital projects would reduce less significant flooding and restore or enhance a number of 3-17 Chapter 3:Subarea Recommen�latiolis I degraded aquatic habitats. Several programmatic recommendations would seek to reduce erosion, habitat damage, and water quality degradation that are projected to occur in this urbanizing subarea. SUMMARY OF RECOMMENDATIONS Please see Chapter 4 for the complete text of the following recommendations, the locations of which are shown on Figures 3-5, 3-6, and 3-7 at the end of this section. Note that some of these recommendations apply in other subbasins and so have already been described earlier in this chapter. Capital Improvement Projects * Denotes Core Plan recommendations, which are those recommendations that would accomplish, at a minimum, the major Plan goals (see Chapter 5). * Maplewood Creek Habitat and Drainage Improvements (CIPs 3120*, 3122*, and 3123): Three interrelated CIPs are recommended for Maplewoad Creek(Tributaries 0303, 0304). In the � headwaters of the east fork of the creek(Tributary 0303), drainage system improvements would address frequent flooding problems in the Puget Colony Homes subdivision. The solution to the flooding, however, is designed so that there would be no increase in flows to the currently eroding ravine that carries the east fork from the subdivision down the valley wall. The next project would stabilize this ravine to stem erosion and subsequent downstream sedimentation; the same would be done in the steep reaches of the west fork. In the lowest reach, fish passage would be provided by replacing two existing sediment ponds, which capture the eroded sediment, with an improved one that is designed to allow upstream fish passage. * Retrofit Retention/Detention (RlD) Ponds (CIP 3127): Existing R/D facilities would be i-etrofitted, ��vhere feasible, with additional capacity and water quality controls. � Tributary 0316A and Wetland 32 Restoration (CIP 3126): Large woody debris would be placed in the eroded channel, and denuded banks would be revegetated along a half-mile reach to restore the habitat function of this once-productive small stream. The north side of Wetland 32 would be fenced. In addition, related recommendations for management of the Stoneway Gravel Mine (Northern Tributaries recommendation NT 1) would address both habitat and water quality concerns in this tributary. � Tributary 0303A Culvert Replacement and Rechanneling(CIP 3121): A damaged 12-inch culvert would be replaced with a larger size to reduce flooding at the intersection of SE 132nd ; Street and 146th Avenue SE. Polluted road runoff would be treated by restoring an existing ' 300-linear-foot storm drain pipe as an open channel. • Orting Hill Tributary (0307) Realignment(CIP 3124): The lowest reach of Orting Hill tributary (Tributary 0307) would be realigned into a new fish-usable channel and constructed wetland complex along lower Jones Road, possibly as mitigation for the construction of the new Elliot Bridge or other road projects in the area. WMC Lower Ceda��River Basin Plan 3-I S • Wetland 36 Restoration and Protection (CIP 3125): Wetland 36 (Francis Lake) is a Class 1 wetland that provides an excellent opportunity for wildlife habitat restoration and enhancement by voluntary actions or by joint public/private efforts. Programmatic Recommendatio�s * Open Space Acquisition (BW 4}: One site in the Northern Tributaries subarea has been identified for open space acquisition due to iis aquatic habitat values. See Tables 4-1 and 4-2 in Chapter 4. * Small Scale Watershed Restoration and Enhancement (BW 5): The Water and Land Resources (WLRD) Division's existing Small Habitat Restoration Program {SHRP), under the direction of the Cedar River Basin Steward (BW 16} would undertake small, labor-intensive projects in the Northern Tribu#aries subarea, using volunteers and other inexpensive labor. See Table 4-2 in Chapter 4. * Aquatic Resource Mitigation Bank Sites (BW 6): This recommendation would allow public agencies to fulfill their Northern Tributaries subarea mitigation obligations in high-quality mitigation bank sites away from project sites, where such mitigation may be less effective. * Water Quality Basinwide Recommendations (BWs 9, 14, and 16): Road drainage facilities would be tnaintained and retrofitted with water quality controls to reduce the impacts of contaminated road runoff(BW 9). Educational programs would be established and a Cedar River Basin Steward would provide technical assistance to address nonpoint pollution sources from highly urbanized systems (BWs 14 and lb). * Water Quality Treatment Standards (BW 12): Sphagnum bog water quality treatment standards would be applied to all development in catchment W4 that drains to Wetland 33 (Webster Lake). * Basin Evaluation (BW 13}: Evaluate implementation and effectiveness of subarea recommendations in controlling stormwater impacts on structural habitat and water quality. * Forest Incentive Program (BW 23): An incentive program to encourage landowners to retain their forest in the rural areas of the basin will be implemented in order to ensure that the Cedar River has clean, stable streams. Incentives will include tax relief, direct technical assistance, forest stewardship classes, a small scale forestry demonstratioii site, and individual recognition of good forest stewards. • Increased R/D and Runoff Controls {BWs 19*, 20, 21, and 22): Regutatory standards designed to control the peak, volume, and duration of run�ff by means of infiltratian or detention (B Ws 19, 20, and 21), and reduce erosion and sedimentation resulting from clearing and grading activities (BW 22) are recommended to help reduce the expected future habitat problems associated with the minor flooding and significant erosion in the Maplewood Creek and Orting Hill, Cedar Grove, and Cedar Hills tributary subbasins. See Figure 4-1 and Table 4-3 in Chapter 4. 3-19 Cliapter 3:Subarea Recomme��dations • Aquifer Protection (BW 1�: Aquifer recharge and groundwater quality would be protected as a potable drinking water source. • Urban Stormwater Management(BW 18): To promote more efficient use of land in the Renton Urban Growth Area,public/private partnerships would be encouraged to build regional stormwater quality and quantity treatment facilities. • On-Site Septic System Pollution (BW 10): Support Sewer extensions to areas of septic tank failure within the urban growth boundary, where feasible. j � _� . � , � a _' � W��fC Lo�ti�er Cedar River Basin Ptmt 3-20 . �•.� —---• `. � �� I , I � i' � I � I Programmalic Recommendofions � ` - ♦ � •����j'������t� � _ 8W 9 lmpa+errxn�of 4Nah!r Q�n�bry fran Rood � i� / � ; 1�+ � `�'' Dravioges�llrbon Areos � t---- �' 8W 10 Q,•S�k Sepric Sysaem Pofhfim i I r_� ��,..; ! � • � � � - - 8W 12 Waerl�ud�rybeonnenrS��dads.8osK7reomeri � �, ` j � � location - 8W 13 Bos�Plo�E� j o aw�d wo�Qesou�es Edu�oAa�rnd v,�C c„�nenr � � ` �� � : MQp 8W 15 Cedor Ri„er Cam.cc� � I_.�_�1 � �♦ � $tiN ib 8osxi S�+.o�d Progrom � oe ^ �������� s BW 18 Urbon Sramworer Na,ogemeM k,in'o�e � �' 't� i i ���' BW 19 Rekrrim/Dek+u�on S+o�dords ` � \ � � MW3 •� 1�12:Mwt.naw2,uw3.1►.12.�3 ew 20 +�v,a�«,sw�d j � MW2 0,1 � I �� 8W 21 Nilka6on as o Sbrm`wkr Nu6goaor,TieaMnenr E � 1 �s� �� Bw 22 Ero�+on ond Sed�mcnanrn Ca:ad Srw+drnds � � �' � � �� � � � � �_�_,�- � 3120.3 Nc .�� s�•..� ♦ -- -� - ---.... � \� ----j' ISO� � ;•�����r�r:�- � -- � I �♦ URBAn! GRGWiH ACEA ! � , t'--_�—'� r' i :r c� � � ��' N �i.'. , 'b�� '_ ' ,��Z�.Z� O _ i , ' r� � , O \ '` > , �.��Z� � � I ; • I / � � � � . � � 3120.1 • -e f ��� � ,' E ; i. \ o���x{ � ♦ f � �� � a'� , ��'� ; - �' p ,l � \ / � J2 • � ♦ � �� ti Y°° � � � �� � 4 3124.1 , r. ,��;ti�' \ i � �/ `� : � � � � ..1 ^ o, ��, � / � � • / - 1 ♦ � � t -- � ��� � � � � ,F MW1�.�' . ,.�„—" � \ / � 13 � � � c �'t� � � // � • � 3122.2 F" - -- - -�- - J1 1 • \ � ♦...�..�• t c� ` � � � Vi ce 1 � I`---'-----'—'��� I �• � la���������• ! 5123�`� .i I ��•�'� ��•�� R ( �: � � �•.��, : oxvv � � \ .♦ � { , � •i�� a� f � /� '� � / �'' ♦ u / �' •� � j.`_h !0 ' �:2 lhtBAN GROWfry ta `� �e I 3124 !• �• � 7 0 4 ni\. � ��v 5.2 � a .i� � ' MOOI� ���. /��' �• � �oJ/� �k a^ r`�o �, , e� ° S� �? IJ ` i �� �O ! �� �o \, os j \'^ 'l' ua�N b� 07°?9fl r'�'_'_'_ ^ ��1 GRpyy)f{ RREA.� a_ �-- � io Jo � � ( ,o i _ /• � � -���I ' �W 0 ,� i ` Maplewood & Orting Hill Subbasins Figure 3-s i 'v rB ' P n in ; Cedar Ri e asin la n g Area Recommendations I N f a9 � ,�`-1 Stream&Stream Number �-j����rated Area(os of 6/98) j � Lake/River Urban Grow�h Area Boundary(os of 6/98) � a"• River Mile�RM) o va 1@ Mik � 5 r� Wedond 8�Wedond Number 3113 Oi Copitol Improvemenl Project location$Number ..•• Subbasin Boundary 3117C�Ccpital Improvement ProjectArea$Number �,,,,�, �vP�� .�� Cotchment Boundary . ��� v�c....rou«�acae�r�, J3 Catchment Number b �,�, ' �..+�i.� Raising the approximately 60 houses subject to flood flows was rejected because the hazard from deep, fast flows would remain. Relocating them out of the floodplain was rejected as being too expensive. Lead Entity: WLRD, Renton PW Cooperating Enrities: COE,FEMA, MIT Estimated cost: $6,500,000: alternative $1,500,000 3113 Person Revetment Modifications (left bank,RM 3.8-4.1) Recommendation: Set back and bioengineer the existing privately placed revetment and revegetate a gravel mine site and landslide scar behind the revetment. I3iscussion: This site has released large quantities of sediment into the lower Cedar River, most recently during a landslide in 1987. This material, especially the finer particles, chokes spawning gravels and causes turbidity in the important spawning areas of the lower mainstem. The steep face of the left bank has been extensively disturbed by gravel mining operations, seeps j and small streams, and natural erosion from high river flows. At the toe of the slope, the mine operator placed a bare rock revetment that extends into the river and has suffered &om erosion. It � has also been overtopped by periodic small landslides,preventing maintenance access. Modifying the revehnent by cutting back and bioengineering its face and buttressing the slope above it could reduce flow velocities and future erosion at the toe of the bank and would provide riparian vegetation. Revegetating the open landslide scar would help stabilize this steep slope. If funding is limited, reduce the scope of the earthwork and emphasize revegetation. The �� property owner may be liable for some of the cost of this recommendation. Lead Entity: DDES Cooperating Entities: KCPA, Renton PW, COE, FEMA, MIT Estimated cost: $800,000 � NORTHERN TRIBUTARIES SUBAREA I�iaplewood Subbasin 3120 Puget Colony Homes Drainage Improvements Recommendation: The King County Water and Land Resources(WLRD) Division should make the following improvements in order to address flooding of the Puget Colony Homes subdivision and local water quality and erosion problems: WMC Lower Cedar River Basin Pla�t 4-12 1. Upgrade the existing conveyance system through Puget Colony Homes (Tributary 0303, RM 0.4-0.8); 2. Deepen and recontour the existing detention pond in Wetland 150 (RM 0.9); and 3. Purchase a filled portion of Wetland 150 for construction of a new 150,000-cubic-foot detention pond{RM 1.1),buffer restoration, and enhancement of degraded portions of the wetland. Discussion: This solution would address the flooding in the Puget Colony Homes subdivision without accelerating erosion in Tributary 0303 and would provide water quality benefits as well. The subdivision currently experiences impaired residential access and road and septic system flooding on an almost annual basis when the capacity of an undersized storm drain, located between the houses, is exceeded. In addition, contaminated road runoff from SE 128th Street is now inadequately treated by a small detention pond in Wetland 150, an 11-acre, partially forested Class-2 system located immediately north of the subdivision. The proposed upgrade to the conveyance system would eliminate flooding and septic system inundation up to the 1 QO-year flow. Deepening the existing small detention pond north of the , subdivision would provide an additiona120,000 to 40,000 cubic feet of storage with another 150,Q00 cubic feet provided by the new detention pond to be constructed in the filled portion of Wetland 150. Such additional storage would attenuate discharge peaks by an average of 15% through the 25-year event, thereby helping to reduce damage in the erosion-prone reaches of Tributary 0303. Water quality in Wetland 1 S0, and in this portion of the subbasin in general, would be somewhat improved by the routing of road runoff not currently detained through the 150,000 cubic-foot forebay, and the water quality would also be improved by reducing or eliminating the short-circuiting of flows through the existing pond. The hydrology of Wetland � 150 would be somewhat stabilized by attenuation of peak flows in the two detention ponds. Restoration of a buffer and degraded portions of the wetland would improve its wildlife habitat ' and water quality functions. This recommendation was chosen from a number of alternatives, which were rejected for various ' reasons. Upgrading the conveyance system alone ($400K) would address flooding but would increase flows downstream of the subdivision into Tributary 0303, which would exacerbate the significant erosion that currently exists in that stream. It would also do nothing to improve water i quality in Wetland 150 nor would it treat runoff from SE 128th Street. Because of the size of the existing small pond, deepening it, coupled with the conveyance upgrade($SOOK), «�ould still not provide enough storage to address erosion and water quality without the larger pond. A regional detention pond located immediately downstream of Puget Colony, as described in the City of Renton's draft "Maplewood Creek Basin Plan,"would make the wetland work unnecessary. ' Other alternatives were evaluated—including substituting an underground detention tank for the proposed solution($600K), using an open channel for conveyance ($1,500K), using a bypass _ pipeline directly to the mainstem ($3,OOOK), or extending the sanitary sewer service to the area 4-13 Chapter 4: Descripiio�i of Recommendntio�rs ($1,400K�—but were rejected because of their inability to address atl of the concerns or because I! of their adverse impacts. I, Lead Entity: WLRD I Cooperating Entities: Renton, SKCDPH,KC Roads, MIT Estimated Cost: $800,000. 3121 Tributary 0303A Culvert Replacement and Rechanneling Recommendation: To alleviate flooding at the intersection of SE 132nd Street and 146th Avenue SE, King County WLRD should replace a damaged 12-inch concrete culvert under SE 132nd Street with a 24-inch concrete culvert. A 300-foot pipe conveying this tributary southward, would be removed to improve the quality of road runoff. Discussion: During 2-year and larger storm events, water ponds at the inlet of the 18-inch culvert ' and backs up to the east along the north side of SE 132nd Street, then flows sauth through a 12-inch culvert at the intersection of SE 132nd Street and 146th Avenue SE and enters the Orting Hill (Tributary 0307} subbasin. The 12-inch culvert is damaged, forcing water over the road at this intersection, blocking the access to 12 houses. Replacing the 12-inch culvert with a 24-inch concrete culvert would solve the road-flooding problem for little cost. Although it would perpetuate the current flow diversion, Tributary 0307 is able to accept the small additional flow with little threat of damage, while Tributary 0343 experiences severe erosion downstream of its confluence with Tributary 0303A and would conceivably suffer from any increase in discharge. If funding were limited, the 300-foot pipe could be foregone, at a savings of approximately S 130,000. Two alternatives that were considered for this solution—upgrading the 18"culvert alone or intercepting and carrying the flows to the upgraded storm drain proposed in CIP 3120— j would both accelerate erosion downstream. Lead Entity: WLRD Cooperating Entities: Renton PW, KC Roads, MIT Estimated Cost: �150,000: alternative $20,000 3122 Maplewood Ravine Stabilization Itecommendation: Reduce erosion and subsequent downstream sedimentation and habitat degradation in the Maplewood subbasin by undertaking the following actions: 1. Tightline two daylighted culverts on Tributary 0302 from their outfalls to the main channel (right bank of RM 1.0 and left bank of RM Q.95), , 2. Place large woody debris in the channels of both Tributary 0303 (RM 0.0-0.3) and 0302 (RM I! 0.4-1.2), and 3. Apply local bioengineered slope treatments, such as revegetation, to eroded sites. WMC Lower Cedar River�Basirr Plan 4-14 Discussion: Capturing the discharges from the two culvert outfalls and tightlining them over the steep, erodible ravine sides could reduce sediment loading in Maplewood Creek by an estimated 5 to 25%. Placement of large woody debris could help reduce downstream sediment delivery and could contribute to the general function and quality of instream habitat. This solution was chosen from a number of altematives; reconfiguring the lower half mile of the � channel to convey flows and sediment to the Cedar River by alternate means($SOOK) or using tightlines($SOOK)were rejected because of their high cost and the uncertainty of their effectiveness. Regional retention/detention ponds were considered for the headwaters of Tributaries 0302 and 0303 but were rejected because, although very effective, they would be prohibitively expensive($S,OOOK). Lead Entity: WLRD Cooperating Entities: Renton PW Estimated Cost: $150,000 3123 Maplewood Golf Course Reach Improvements Recommendation: The City of Renton should replace the two existing sediment ponds on Tributary 0302 with one designed to allow upstream fish passage at RM 0.35 and stabilize the eroding banks of the stream above the pond with large woody debris. In addition, the City should consider enhancement of habitat in the reach that passes through the golf course to facilitate upstream fish passage and provide rearing and spawning habitat. Discussion: The improved sediment pond and stabilized upstream banks would not only allow anadromous fish to pass to upstream reaches, it would reduce the frequency of sediment removal I with its associated costs and its habitat impacts. Enhancement of the reach within the golf course (RM 0.2-0.4) would encourage use of the relatively good habitat of the Maplewood ravine 6y anadromous salmonids. Lead Entity: Renton Cooperating Entities: WLRD, MIT Estimated Cost: $350,000 ' Orting Hill Subbasin T 3124 Ortin Hill Tributary(030'n Reali nment I g g Recommendation: Realign the lowermost reach of Tributary 0307 into a new fish-usable �� channel and a constructed wetland complex along lower Jones Road. (Note: this could be used for mitigation for construction of the new Elliot Bridge or other road projects along Tributary 0307.) 4-15 Chapter 4:Description of Recommendations Table 4-3 Tributary R/D Requirements - Justification by Speci�c Catchment � Subbasin and Trib#1 R/D Justification Comment Catchtnent Level Mainstem Cedar River 0299 0• Insignificant benefit of R/D.Cedar River Appiies to valley floor lands with direct MS1 through MS15 is a designated receiving water. discharge to Cedar River.Otherwise � Level 3 applies on valley floor.For plateaus see BW 20. Mainstem Cedar River 0299 0' Insignificant benefit of R/D.Cedar River Levei 0 only with direct discharge to MS 16,MS l 7 is a designated receiving water. Cedar River,otherwise,Level 1 required. Ginger Creek 0300A 0• Insignificant benefit of R/D.Limited Require downstream analysis to B1,B2,B3 future development.Less than i0% intersection of Lake Youngs Way SE increase in future peak flows.No and Royal Hills Drive SE.Small but significant current R/D in place.No nonzero risk of increased channel significant current problems.No SRAs erosion. present.Ample conveyance capacity. Maplewood Creek 0302 2 Avoid future aggravalion of significant Basin on urban side of UGB.Low MW1,MW2,MW3 0303 current erosion problems.Protect projected%future forest cover. recommended 5500,000 channel stabilization/habitat project. Molasses Creek 0304 2 Protect SRA stream habitat.Prevent Basin on urban side of UGB.L,ow F1,F2,F3,F4 aggravation of current stream stability projected%future forest cover. problems. Madsen Creek 0305 2 Protect large public investment in stream History of catastrophic landsliding and M 1,M2,M3,M4,M5, 0306 and sewer line stabilization and LSRA sediment transport.Continued risk of M6 stream habitat and wetland. future problems. � Orting Hill 0307 2 Prevent future public expense from Nistory of small problems and drainage Jl,J2,73 aggravation of cunent stream stability projects to stabilize channel and improve problems. habitat.Urban side of UGB.Large future development potential. Summerfield 0311 0• Regional tightline serves upper half of Approximately upper 50%of subbasin SUI-upper subbasin. can Ue served by existing tightline. Summerfield 0311 1 SWDM peak 11ow standard.Adequete Tightline intercepts flow from upper half SU1-lower given reduction in creek flows resulting . of subbasin. from tightline construction. Cedar Grove 0308 ( SWDM peak flow standard.No Some risk of future channel erosion. CG1,CG2,CG3,CG4, 0309 significant problems or SRAs. CGS 0310 Cedar Hills 0316A 1 SWDM peak flow standard. CHI,CH2,CH3- unmined `' Cedar Hills 031bA 4 Special design/Master Drainage Plan for Master Drainage Plan process CHI,CH2,CH3-mined all subdivisions regardless of size.Also recommended for custom design to known as Large Site Drainage Review in restore pre-mine water quality and the revised Design Mnnual. quantity that has been radically degradeJ by mining. * R/D exemption sub}ect to DDES approval as per Basinwide Level 0 R/D standards. 4-71 Chap�er 4: Descrrptiola ofRecomme�:�latiorrs � � . � � ' ' � ..,,. 1 � M� � / \ / \ !1 I I . ` � 1 '�% ]' � % ;,_•' � -- , Figure 4-2 a � j ► i � . � ' i / _ � % ; ��;� � ;� 1 1 .LGS\i'� � fi 1 \ .\ � � \ � ��, ��, { "JdSI f� M52 �f�, ' ' j2 � \` � \,_-.`�`. i / �: � 1 \ , � /MWL�1 J 1 �, � 1 `\ S'���' � Tributary Retention/ j - � / � . � MW 3 �� 1 13 V '- f��1 � �� � �y '`y � ' ' 4 �4' Detention Standards � ` � � n ��,,,�• ��' —� , _ _- �• �inus�. � r�— ��G�y�� ,l'� - _.__ ... � � `�ii+ ��� � _ ---_. � ��; �� �__.�7rt59� � 1 �- --= �� for New Development ! -�... M53 � ��`� , `` 1 .. - _� ' "- - ' a � ) �\/� .�- . ''��` �_ ` � 1'� `` -�� � '_"��� � � Cedar River Basin Plannin Area � - i� �� Ft � � y� ,;l �� �� \,_ J\ ` , . , `-- MZ , , � � . 9 f2 " ` � Recommendations ` \ ► CH� - / :� � � i���.. \ �1 � i � ,: ��„����.< t_�._� �� \ �.\ . i ` 1 M3 � �\ �1`.. �I � � cj��` � ���) � , AA6 1 ` `t` =�,� � � � � l '�P\```` �;�����.. �\ � �_ ` � �� _� ♦ � i �,, .. . ���' � � �. � �r ,r �\ . ` � .. � -� � � � ._� . . � � �� � / PQ � � ��_ t fd 1� AU \ M5�`; 1 t � W4 � ` ' 1 a ,� ♦ � 1 I � � ,�,�„� . �^"�,�'� t1' 7 � K � �, `�'� '` � r--�� �i � ; �• �twar v. ' 'i ' � ' i �i` - ; . �%_ � � � .1 . „� v� _ � .`9`..� �.� ' ,� � _- , ' �� Sheam � j �. � ` r �` ,,�"'�a� �� \ M510 � OV� �3� � � ` �` � 't �♦ / ' � k�� , �\ ; ,- `� PS �+�' ..P,1� , ��` ��.- ��_;.� �, i T' � �� ` ; , �� lQke/R�er � - � ,'�'t ' m ' � �i _ -`�� <,���t � i`�•� �� !. � - - - r� m� � _ , '. �:--a Wetland ' - ' �,, . � �i �.F�.;-�� i I � � r �� � � ' _ ` , , � ; � i � - . _ � oz � +.�s�i_ �� / , '_ _ - # � a,r� , > .;}��r'_.`"��, ��,__i' rs ) ��� �3 . ' �../^ BosinBoundary 4 a i . MS ' �C ' � ' I, �—�� ` .-vo"� `� � �. ` � � �� •s _ _ `' _" `_ ���� Catchment 8oundary f _ , - � � ` '. �'"` "� - `�� � =�i�`� � - � � MS2 Cafchment Nvmber � � / l �Y- i` � ^PI 1 \ - �` � , ii �C` . . ` ,w{2, - ri 1 , , ` _��� � . !E.'�.,� 72A � te j� . � 1 \ � i i ` L I ' ` T2 �l�\ I �\?� `�.� ` / ``' Y` : MS13 � �` � �I �.. �Ya J. � - ..� � - �� V �� �. � � ' . ���r� �Lc�-`�"�..� � '�_ ,nn.e`, ,.'� . '/i _/ �� ���`` �a � Leve10 � I i �-:� ` �, , ♦ �--, -_ . �'- � � ; ��y J�, _Mvs_♦; Mva� �� � ,.- �i� � � �• level 1 j � ,�. . , '`'�� � .� ,,• "��-���.�.� i � � �� ;. �,�y� � � � . �r;'�v,:�i �._.--`� �6Ve�2 � / � ����+.�,�- f\.�.i����wtt�•�i �� i � �i Level 3 + �� � e+su ._ � ' � ==-^t� � � 'Hs�� � — , __ ^ � �.�.5.' level 4 i � i � � � _ � : � �`�-��� �` �� i ' � �` i �` `� �`� 1 �,� ` � �� i= �� � Ms�e Y _ �'`� NOTE: Refsr ao Chaprer 3 for � • ,�'�`. � :�-` ,-i,. . more detaited mops and infamotion. ' �� �� � � ���� � � _ �'�R2 �\�� t `� �,�i 't f / � l � � _ �I , � / 1 /��� � R3 ������ � � � / ��_��..�� . � � 4����� i� �ti � 7 9 � �'`� `•✓~ •� N i i � �x,:...,� � � / ^R5 � a, 46����.��..� •1 '�^.'� � `�� i� ; � \ ` \ Programmatic Recommendariau � i " � j { � BYY 1 q .Relenr,�+,/L�eqsr�kon S�.dords I ,��� 0 1 2 Mias j ! � fevel!:CH i.CH2.CFt3la ihmMed Arecs i I � � i �� ! tevei�!:CN i.CN2.CN3(«eYx�cd Areas � �� j. BW 20 Raare Ro�crion Sandord � ;� i a� � ' � 4 � Plalew.lreos,NS Cakhrenh i �` 1 p^�'�'�, Map produad by: � j ��+': � � � g �'� Yisual Communication i GIS Unit, � �`" -`✓��, O s Public0utreach5ection i W8 1 x<y�.�~ 9Wi�Ma.TI11MSTDSF211K {, � ' i #� #�,.,,_ . .�---- .��«. . .,»..��-��- . ..gr.:h�-��..,.-.,�...,�. ,�, - _, -_ . -z�.�,���-�--.a.�.,-.��-�--�_�,-.�-T-.�.�, -_._.���.�.. ,.._� - -- -� .� -�. ..--,t �.�.-�- ._ _.. --.._._ --_ ._r_�� __- ,.._.e - --� .�--�-_: .. . . .__ -:�.._,. .�-,.. .: .._.. :. _�_,--.,<: � .- . ._ ... _ .�..._.. . .._. .. _. ..._--7a-- _.�__. . _ _ ._ .! Appendix B Downstream Drainage Complaints 23 October 2014 I TO: File I� FM: Craig Hislop, P.E. RE: Drainage Complaint ?006-0081 Close Back�round: Mr. Close reported a landslide in Tract A of the plat of Hideaway Home Sites to the west of his property on or about the 16 of January 2006. I left my card and a door flyer at his home on the 17. I left a telephone message on the 18 when I did not hear from him. He returned my call the evening of the 18 and again the morning of the 19. When I spoke with him on the 19 he told me a King County employee by the name of Paul had stopped by his home and looked at the slide. Mr. Close told me that Paul had not been concerned about the slide. I spoke with Mr. Close again on the 25 of January and received permission from him to access the slide area through his property. The Close backyard rolls from a relatively level surface to a gentle slope. Outside the fenced yard the ground surface continues roll steeper. The slide appears to be completely within Tract A as shown in the recorded plat. The landslide is generally made up of the top two to four feet (2'-4') of surface material. There appears to be a horizontal clay layer with a pervious layer of free draining soil on top of it. I saw no further evidence of cracks or other movement outside the immediate slide area. The top of this slide is approximately seventy five feet (75') horizontally and twenty five feet (25') vertically from the Close house and does not seem to present a danger to the home. The landslide is approximately two feet(2') thick at the edge and forty feet (40') wide at it's widest. It slide to the bottom of the drainage course and blocked the creek until it was overtopped by additional flow from the creek. There are broken trees, branches and root masses at the bottom of the drainage channel. There is a significant amount of sediment that has been washed downstream. I walked both upstream and downstream from this slide. Both directions had many additional slides but of a smaller nature that also contributed sediment to the drainage channel. The slide areas could be easily identified by the gray wet soil with little or no vegetation. There was also soine evidence of channel erosion due to high runoff flow. There were a number of outfalls from previous development projects that were in a state of disrepair. It appeared that most of the outfalls have not been inspected or inaintained. I found leaking and discontinuous pipes that have been discharging and incising the highly erodible slopes. There where also some poorly designed outfalls that allowed runoff to discharge directly onto the slopes. Whether the discharge on the slope is accidental or purposeful it has contributed a considerable amount of sediment to the channel. 23 October 2014 2006-0081 Close Page 2 There is one location where an eight inch (8") �;-ater service line has now been completely exposed. The runoff eroded the channel material around the pipe and has now piled mainly organic material against the upstream side of the pipe. I will attempt to contact the owner of the supply line and inform them of the current condition. Where this channel meets with the greater Cedar River channel the City of Renton has constructed a sediment pond to catch the majority of heavier sands, gravels and cobbles prior to the creeks flow across the Maplewood Golf Course. This facility appears to have done a very good job of stopping the transport of sediment further downstream. It does appear to be nearing its capacity for holding sediment though. Recommendation: I recommend a repair of the outfalls contributing erosive flows to the sides of the drainage channel and removal of the sediment in the City of Renton's facility. '� :�� ����� g^� �, � r ,! '' r-e A � f ti� � ( � iF4 , '`.l�,,M 'i� �i t�'i.} �a! �.a4 �� .! 4. S . F�� .����L'~. ,•^�R7P � .. a: . `� � _:� •� � '�t s� h _���. :'b ., � �?��.:bP k�'s,� � •:!i � � ; �4�lAa�r�4� '"=� � . �Tij 'S` ��� .��- a �, .. �,r �i�c `$ : y�•�� st. 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'�� �• � _ y'���Cl�.,� -t-� _�--`�������� .`..:� Photo 1: The landslide behind the Close property �vithin Tract A of the Hidea�vay Home Sites. 23 October 2014 2006-0081 Close Page 3 a � K�����`_ it � �j�����\i���(ti�-� �N�a �t��� ..�s - .,� . , ��`� ��3i •r-� � .� �' ,'�~ yr.� �k f r n v..:.� ,,,� i �M1 �� R-� � .:i �'_•,� �:�� f' � +i+�i,ri .l� a.. ��r � ,�o �� t; `i' �yyl+ •�^ - � �. , ��� ` � ,� .5� -�•��,�T,+- {��-\._. �SS�" ._:3��'7'S 'd i ` I .+ � i $ � �� T --- � �^� ,�.:}�� �� ��`� y -.1:�-!���'�� .����.'�,T�-., '"�; d�-a�f �r��Z�, ' 4�` ,�: > .. i' ..•������+ .,' � �,,. � `��: � �� �.. � � �_l��" i- �.t��.e"'`R��x.,3\� �� yaC:- .�� �tI .• 1 ���'Y r r, s `� xl.r � �i 7 � �' y ��` f #= iw � � � ��.�•t +�,;��� .F P k,�+,�.�y��!r� ,,���w�� �� ����.__.,_;y,� ; ����.,y���� _� _�,�,� .�_. •� '�-, �''' ,� �.� � '°,��. ,s ' � :�`� �_��;. _��� •�i; ��e �.� -�?�'�,�;��,� k �'' .;��` "' `'� r � S . \`d ...� AG't �y� &a ►:f-,-.2='e - �L� °�.'1'`'��'�' r . i !--`-�t. V � ����Pe*=.Js- �':� i��r' t - � �� 'i. �' J. _ ���' 'f '+'��S+i►;� ,,�. .�� `-"����„�.���y 4 } ��� _ -- ~���4� !t�. � '� ts� t, � `-`�-l�i�i3 4:a S��'ys.��,� t �`` �.�rQ ����,i� 4_ �� ,�'=r� �:�rr , �Y.�'i'�,;;�► ;. '� j, �'.:-Q , �_ ��� �, � _ �. Y �� v �� F� 7�L . , . _w..�;1 Photo 2: The landslide debris in the channel and its course now. � . , � r, , , I '� � '��: �,i„s,5 � -.��+� e,,;,,•� � r ! �r� � A �S l�,7f.-r,��''ii �' t�, ,,� r � �;�`' <�dt'�;;4� ���� t'e s. .:,;Y=�j� ,R: +� ��'�. 4 s�.�, •�i�1�'��`ti��M�l�����r�F� :i� ��'_ . ,,./ ,� 4 *y.' r y�„SY,� �4i�a, , �.K.'.!�� .;�X\."w `�*`"��.41�"q�1' f'"\� ' ,p�'� � �:}t� i` � ,::r � -�. �� � t J �, ��?�,') ' �'. w ;� ., r �t xiY"' '� t >`,�i � " -���. .f! `k+�Y� � � �` . �i�Z'1:��'f � +�� �: �'s i -.�' y,►y, ,��;7"'�, ;�+` �.. 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A�A '�r �'r �' �� '�i'.i,c.5�i ' Photo 3: Typical of other landslides in this drainage course. 23 October 2014 2006-0081 Close Page 4 ;� <� ~� �v \" ' �� rii, �,�` �t t;;;;%� ;�• � � �^ ' ��� � ,� '�'�'�.., 4.�' � � � xN�� ,'� ` ��� ( " 9�, • . � . � ` ��`�'�� �4� � •��� �} , �� ' � � ` . l� /1 _ • � `4 T'� l i# � `� � '4 { �t� �. . �:. w., r-. :y�-l��Y. i"F 1 s f f ��� �r ��,a,� M 4�� _ t _ .�- p�'� � ;:T ' -:'� - �A '�ya'�i �+7`� � t _ . � �,''�. � '�} _ �- �� ��•�K . v _ M .� - '�}y 1 ��, V j r�. �r +���.i,Y�. 'Ec `_� Y ��[.! ,1. �. „� i �4'-- � �. _ . .fi'r , � ,��. _ _ i �•.:. � `'.A ... . y . �.� �. A -, � f , �.�+�,,� :�t,,�;+F.�._ � _ _�' � , �CT� �.•'_r �.•. 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'` I �Y� I 1 I -�, �tj�ti fr^� ��( ��!,7T�� f,aw ��� Jl � � ,r '(. }r �:'6:c,,t , ' . �i�.M'C a ��;�. -�.- .� � .�, � .y,,.: r�f. � � �� � w � �' s �� ',�� i � t° '�Y�.;, �. . � ��, y�1� � a.. � J � �. a! c i � 9: �x���� . . w' . f 'l ��,$ 4 ��Y�, , .,� , �, ,� � �, � �., 4 , y �, ,� �� _, �-. �' A . * ,' , _ � � ��;.� �:� _,.. .��� � � ��� ', ' � �,,�, w� � ;,� �_�`� .� 0 0 � � � �,�.�� .. � n�� .s � „ .�,x,`�,?��� >: .�; b N (� � ��`��;. " ?r, ,�:. � y� ,. �, C i ..� ;q�,,,;,,, ..s.�•., fa� .� �: i.. ;, ,'t �N s �, �s � � w •. �� �' : : ' . , b � ..;'� ��� �i I � p O �� .A� i� v � ti �1i �o P � ' � �� V � � � ' , .� �I� ;�� ! � �P'�"� � t�D! �A O � p bA � t�� *�Y,' �, `� � ��� � � , y � � � �a�', �� O c+� o � � �� � ;�' �.j �� � :�' ��.�w` '�'� a c� c�1 a r .t`.,:V;. . „ �•ti�» � ' ,., . _ May 22, 2012 RE: MAPLEWOOD CREEK STORM OUTFALLS The purpose of this letter is to bring to your attention the deteriorating condition of three stormwater outfalls that discharge into Maplewood Creek just upstream and north of the Maplewood Sediment Pond and Golf Course that are located within unincorporated King County and the City of Renton (see enclosed vicinity map). The three outfalls labeled Outfall 1, Outfall 2, and Outfall 3 originate from conveyance systems that begin at the top of a steep forested ravine along the south and east boundary of Heather powns Division No. 2 (see detailed vicinity map). Heather powns Division No. 2 was annexed into the City in 1977 pursuant to Ordinance No. 3143. According to King County record drawing G-146, the outfall designs were approved by the County in 1962 (see enclosed drawing G-146). The portion of these conveyance systems within the Heather powns subdivision consists of buried pipe and then transitions to an at grade tightline system anchored to the slope. The buried sections of pipe lie within the jurisdiction of Renton; however, the tightline sections of pipe for Outfall 1 and Outfall 2 lie within King County's jurisdiction. Outfall 3 appears to be entirely within Renton, but a survey will need to be conducted to confirm this. City Surface Water Utility staff conducted an inspection of the outfalls on February 15, 2012, to assess their condition. All three outfalls had completely failed which has �esulted in significant undercutting of the steep ravine and sedimentation of Maplewood Creek and the Maplewood Sediment pond. The existing condition of the three outfalls is described as follows: Outfall 1 Outfall 1 is located at the southwest corner of the Heather powns Division No. 2 (Photos 1-1, 1-2, 1-3, and 1-4). The outfall's conveyance pipe begins as buried 12" diameter corrugated aluminum pipe in SE 4th PI. The pipe continues south for 130' in a 10' storm sewer easement delineated on the plat before transitioning to an at grade 18" diameter aluminum tightline pipe system anchored down a steep forested ravine. The storm sewer easement lies between two homes (Parcel No. 3211100690 and Parcel No. 3211100700). Most of the tightline system is located in an unplatted tract of the Maplewood Heights subdivision. Approximately 50' from the top of the slope, the pipe transitions to an 18" diameter CPE pipe for 70' and then to a buried 24" diameter CMP under what looks like an unpaved access road. At the downstream side of the access road, the 18" pipe protrudes out of the road embankment where the slope below the access road has failed, exposing a 15' deep gulley. Further downstream, in what was the outfall, broken sections of pipe lay at the bottom of the gulley covered in May 22,201Z vegetation. The gulley transitions to a small stream which is tributary to Maplewood Creek approximately 600' downstream. The area encompassing the gulley appears to be contained within private property(Parcel No. 1523059187). A title search was completed for this parcel and the unplatted tract, and no drainage easement was listed under the exceptions or special exceptions to title. Access to the buried section of pipe at the top of the slope is difficult due to the planting of arbor vitae and construction of a fence within the easement. Outfall 2 Outfall 2's conveyance system originates as a buried 12" diameter concrete pipe in a manhole at the intersection of SE 4th PI and Chelan Ave SE (Photos 2-1, 2-2, 2-3, and 2- 4). The pipe continues southeast within a 10' storm sewer easement delineated on the plat. From the manhole, the pipe is buried for approximately 150' between 2 homes (Parcel No. 3211100930 and Parce) No. 3211100940). At the top of the slope, the buried pipe daylights into a concrete flume and then to an 18" diameter corrugated aluminum tightline pipe that is secured with two concrete anchors. Just beyond the last anchor and approximately 40' from the top of the slope, the pipe terminates and discharges into 20' deep gulley that formed when the slope became unstable and failed. What remains of the outfall are sections of mangled aluminum pipe at the bottom of the gulley adjacent to exposed sandstone. Because of the proximity of the slope failure to the homes at the top of the slope, there is a concern that continued erosion and subsidence of the slope may place these properties at risk. Maplewood Creek is located just downstream of the gulley. The tightline system and outfall are located within Tract A of the Hideaway Homes Sites subdivision. A title search was completed for Tract A and no drainage easement was listed under the exceptions or special exceptions to title. Access to the buried section of pipe is difficult due to the placement of a fence and shrubs in the easement. The location of a carport may also make it difficult to access the pipe. May 22,2012 Outfall 3 Outfall 3's conveyance system begins in a manhole at the intersection of SE 2"d PI and Chelan Ave SE (Photos 3-1, 3-2, 3-3, and 3-4). The 18" diameter CMP lies within a 20' utility easement on Parcel No. 3211101039 and delineated on the plat. The pipe is buried for approximately 140' before day lighting midway down the ravine. Once above ground,the pipe continues down the slope for approximately 15' and then terminates above a 10' depression where the slope has eroded causing the pipe to separate from the outfall. The top half of the pipe is missing. At the bottom of the ravine, a roughly 20' section of what remains of the outfall pipe lies in the Maplewood Creek channel. A considerable amount of sediment has been deposited in the stream channel. The tightline system and outfall are located within Parcel No. 1523059007. As with the other outfalls, access to the buried section of pipe at the top of the slope may be problematic due to the proximity of a fence and vegetation within the easement area. Since the outfalls and associated conveyance systems for Outfalls 1 and 2 are located within the jurisdictions of the City of Renton and King County, it is in both our interest to work together to develop a solution to prevent further erosion of the ravine to minimize impacts to water quality, property, and public safety. At your earliest convenience, please contact me at 425-430-7248 or rstraka@rentonwa.�ov to set up a meeting to discuss the best approach to addressing the condition of these outfalls. Sincerely, Ron Straka, PE Surface Water Utility Supervisor cc: Lys Hornsby, P.E.,Utility Systems Division Director Allen Quynn, P.E.,Surface Water Utility Engineer Outfall 1 Photos �y - � : �._ . 1 f . '!' .� ` � i.. � �' �� ��"' �,� - a `{�� s '�i �y. �� '� h ?AC a✓i� , s / F t��.l' ��'a, . 'r �� ' .�� � � ¢; � � , � �`.: �z' ���'' ' �. . r. � s � � � r ,, >=�.• yy � � �t ' ' �+ `~�"l_�t ; `3�sy ^I:^it�. � k�? ���� � �� " �� '3"° . tia 1�� r�+#�"'�j'�`y���� ��. � .x r�.� � � , . 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'�,�� .�l#`1Ra�3i� '.lP YB�i^�_ v � Photo 2-3—18" aluminum outfall debris at bottom of Photo 2-4—Inside gulley looking downstream towards gulley Maplewood Creek Outfall 3 Photos r. ,.�f��� r�, 1 ; �e ik .� ���_� �I a ` :I 14 � � ` ^.� �{��s:#+ ,� , �� ''�� '�, .� _� n� � � . . 3 t^ ��`.�,� `Y�4 . �' '�t:w L a � ..},��y i`M� .:h 'dl-+�:=` t�� �� je t t - ��. � ��. � _�£. . •.t � 4.e�-'i +s, r�`'�•p'�.�. :Yc�i.� £ ]f'-:.. {� ' M1 � ...m ---_ L sysK'a•�: y. � .. �-.Y'A' . .ia.. ,�.F- ,�-a"t ;f ? ,i, � ,`k�` ? . , - ��. __ .� r � �`a� �, . � . � ..� �" - � . �..- � <— a�;� ,ati r c a � T�� I �'�'. � '�� �*�`4� i��ax io ,j* 1 � ��`� . _" . :� '.,a . ��,sn � ����i3��� �,��` \���� �y`�r�{'s��� ���.' - ; �y � � .a� �.4�v�� ���a 'r �*Y�)�`w,t� .x � 'd` � -�� f. ., , �,r _. _. . �� /���'�: � 'i�s�"�'� �`3g�j�,�`sr w�-:a � . - " s �,_ . . _ -- ���, 1• �". +r ���*' �ciry'����t S�n'}�,.�� � _; .x� g� ._ N ` . .. ^ y �_:'K � � �. r i �a �,., . �� � � � ..,c,� : �� �� .�r +��'� i�•t���a•��y 0���,y, ti _ ++f _. -. 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W'p� 1 � L� a,a"`Y, }y ..� ,.I� � � . `� L rf „: � � 'r � •,.rK # � ���M , �' � ��� .�-t� `'�' �•. �f.^�������: �a i �'�" ..�. �7i�.�.J. �• _ ._ �_.. . , '`�'e? F . .� � .. �Q�t :iC,�"a .. � . .._ . �� +f .�-.� Photo 3-3—18" CMP outfall debris in Maplewood Creek Photo 3-4—18" CMP outfall with top half of pipe missing channel � FILE�'O. 2O�4��647 I � King County NAME Department ofNatural tn I Resources ADDRESS 14017 SE 139 St Water and Land Resource Division PHONE 425-226-0690 TB PAGE 656H3 � KROLL PAGE 810E DATE DRAINAGE INVESTIGATION REPORT �,�INT.D[VISION 4 �vrri�,s CTM FIELD INVESTIGATION Met Russell Berg at his home on 8/20/14. He and his wife have lived there for 38 years. Their property is 4.93 acres. The house sits on the northem portan with the rest of the land dropping over 100'into a steep wooded ravine with a seasonal stream that flows from east to west.He explained his land is n unincorporated King County(KC),but he is now surrounded by the City of Renton which has allowed many homes to be built including 46 new houses directly noRh of him. Mr Berg called for several reasons. 1) Many of the trees growing in the ravine are falNng. They have the potential to fall on his house and/or neighbors adjacent to the ravine. Mr Berg would like to have some of the"dange�'trees cut down. It is doubtful permits would be granted,but I told Mr Berg I would provide him with the agency he should contact. 2) No fish have ever been seen in the stream,yet the City of Renton now says it is a fish bearing steam. It is my understanding WA State Fish and Game DepaRment is the agency ihat identfies and tracks this information. I will try to find out how they identify the stream. 3)There is a 4-5'diameter pipe he said the county put in that discharges large amounts of water into the ravine causing bank erosion He pointed out the pipe is located directiy east of his property(at about 13839 144"'Ave SE). Researching plat maps of the area and KC Roads mapping,I was unable to find any records of such a pipe.4)Since cameras were installed at a nearby elementary school cars bypass the area using SE2nd PI instead. With the addition of the new homes no traffic control is planned at the intersedion of 139'"Ave SE and SE 2nd PI which they fear wi1 cause accidents due to a knoll just to the east of 139�'Ave SE causing little or no site distance at the intersection. The intersedion is at the border of Renton and unincorporated KC. When asked if he had brought that to Renton's attentan when ihey were evaluating the new housing project he said he had,but they did not require the developer to install any improvements. SE 2nd PI was temporarily dosed due to the new construction on the day of my visit. 9/9/14 follow-up. Provided Mr Berg with phone numbers of the other agencies he should contact and told him we did locate a plan sheet that indicated a 42'pipe that outfals on the other side of the stream and that we would request KC Roads armor the outfall area,but if they could not we would try to elevate the issue to an Engineering Review for possibly an NDAP project. 9/10/14 Russell Berc,7 emailed four photos of the pipe and downed trees in Maplewood Creek. •��������6»����� �,�,� i ��`�+�.�.� �.. � ?' �:�— �� : , : ���!� � —, ,� , ., � N , t`�_�J{.�I,l.'��� ����� ' . 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J�_' �����► `ir�jE' ,� • . �, y_ � '� � �=-_.�-.'..�i--"''r��1�1lI��7�1.[1 I 1)1�'.'t� I i: '� � � r� Preliminary Technical I�nformation Report Plat of Copperwood Sectton 3.0 Off—Site Analysis TASK 3 FIELD INSPECTION Paragraph 3.1 Cornreyance System Nuisance Problems(Type i)and paragraph 3.2 Se�ere Erosion Problems(Type 2) Nearly all of Maplewvod Creek Tributary 03U3 downstream of the proposed Coppervvood Development . is within King County as has been this development site until quite recently.Complaints about conveyance nuisance problems and existing severe Erosion problems a�e�tikely recorded with King County and not with the C"tty of Renton.To only review C'ity of Renton reports of downstream erosion problems for Maplewood Creek Tributary 0303 does nat identify the longstanding probiems known to King County.King County records of erosion probtems of Maplewood Creek Tributary 0303 should be � reviewed and acknawiedged in this report. Attached to this email is a series of pictures I took during thjs past week of some of the erosion damage that has recently occurred on the portion of Maplewood Creek Tributary 0303 that passes through my property. My property begins just downstream of the nearly ninety degree turn that Maplewood Creek makes from a generally north-south direction as it paues through the Copperwood Plat to a westerly direction a short distance south of the Plat as shown on the maps included in the subjett report.Along this nearty six hundred feet of Mapiewood Creek st�eambed that 1 own there have recently been a number of large evergreen trees topple over due to washing out the soil unde�these trees along the creek bed.One large cedar Vee recentty fell in a southeriy direction from the north edge of the creek into the back yard of the house at the top of the ravine miuing the roof only by a few feet.The large root ball of this tree �emains in the stream bed partiaily blodcing the stream flow. i believe this report should be revised to acknowledge there are serious erosion problems currently existing below the proposed development 3ite. Thank you fo�your consideration of this issue. � Russell Berg 14017 SE 139T"St. Renton WA.98059 . • � r��c��v�� EXHIBIT 11•1 . SEP 0 2 2014 c:��v o� P�r�TON n'_L.NN1iJG Oit�l$ION