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Home My WebLink About03894 - Technical Information Report � i� nr�L TECHNICAL INFORMATION REPORT Marriott Residence Inn 1200 Lake Washington Boulevard North Renton, Washington City of Renton Permits: �, B150�8433 ' U15008434 Prepared for: Western International !� 13647 Montfort Drive !� �-�� Dallas, Texas 75240 �� a,Ac�Bs ' `t��F �!1�. ^t �� ' ✓ `� November 5, 2015 � � � � � � � � Revised February 23, 2016 I / ��:s ��2?6�Y``.-.� Revised April 8, 2016 ',, �� . � �`"�"'t� Revised May 18, 2416 O� __., '`�_ ��6-� G�"�'4 Ci � �1► F G7. , Z , .. . - - � . , -- _ n '� ��=;AN�H OFFICES • TUMWATtF.WA • LONG BEACr� ":� • = -. _.E ..-i, • �.!, � r :. O - 'i ? v,n�M barqhausen�"^� y� ��U► a �p. wF- r��C ENG��' � 89y �� N�- �l�lcc ! TABLE OF CONTENTS Paae No. � 1.0 PROJECT OVERVIEW 1 I Figure 1 -Technical Information Report (TIR)Worksheet .. Figure 2- Site Location 9 Figure 3- Drainage Basins, Subbasins, and Site Characteristics 1 � Figure 4—Soils - 2.0 CONDITIONS AND REQUIREMENTS SUMMARY i6 2.1 Analysis of the Core Requirements 17 2.2 Analysis of the Special Requirements 18 3.0 OFF-SITE ANALYSIS 19 4.0 F�OW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 53 A. Existing Site Hydrology 54 B. Developed Site Hydrology 54 C. Performance Standards 54 D. Flow Control System 55 i E. Water Quality System 55 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN 81 6.0 SPECIAL REPORTS AND STUDIES 92 7.0 OTHER PERMITS 158 8.0 CSWPPP ANALYSIS AND DESIGN 160 9.0 BOND QUANTITIES. FACILITY SUMMARIES, AND DECLARATION OF COVENANT 270 10.0 OPERATIONS AND MAINTENANCE MANUAL 303 =��1-4 �:r dc; � W � � W / 0 �"" V W � � � Q. O � � • 1.0 PROJECT OVERVIEW The total area of th�� ..,_- ��: � __ v -..��_x:� d��Y � •�+ __ -_ _ - -'�_- �_�_ �� . �tr�- ., � ��r =. portion of the Southeast�quarter of the Southwest quarter of Section 5 ana of the Northea�t quarter of the Northwest quarter of Section 8, Township 23 North, Range 5 East, Willamettc Meridian, City of Renton, King County, Washington. More particularly the site is located at the northeast corner of Lake Washington Boulevard North a�d N E. Pa-k D�i�.�� Plea�e �er tn� attached Vicinity Map for an exact location of the project site Under existing conditions the majority of the site consists �` f:;res:ec ,a�,�. Tn��e s ais� ur�� ar�a �n the westem portion of the project consisting of gravel surface area which serves as a parkir� lot for vehicles totaling 0.47 acre of impervious surface. The remainder of the site is moderate and steep slope till forest. There is also a Puget Sound Energy power easement for transmissicn mains comprising most of the southern parcel on the project site. The steep slopes in the central and eastem pertions of the p�cjeet site �,�•ill !^�ake �? d�fficult to �onstruct � parkirg `acility an� I parking Ict Runoff from ;he upper r�acnes cf tne pro�Ect s�tz �v�ll sneet flov� �nto the �ack cf ;he reta�r�ng walls constructed along the eastern portions of the overall development. These retaining walls I :vill collect upstream contributing runoff in their footing drains and will bypass this runoff around ' the project site. This overall pr�ject only com�rises 1.17 acres cf land. most of which will be imperv�ous su�ace. I approximately 95 percent impervious surface, with the remainder tifl grass landscaping. ', The proposal for this project is to construct a multi-story hotel with underground and aboveground parking. Approximately 70 - 75 percent of the proposed area to be developed wiU consist of ' rooftop area with minimal landscaping and the remainder exposed parking area. Access to the s te will come from Lake Washington Boulevard North. ', . = � 4 ,_ L FIGURE 1 TECHNICAL INFORMATION REPORT (TIR) WORKSHEET � � KII�G COLJtiTY. W.�SH1tiGTUti, Sl'IZF:�CE �'��.�TER I��S1Gti MA�C.aL TECHNICAL INFORMATI�N REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATlON AND PROJECT ENGWEER � ' DESCRIPTION ! � Project Owner Westem International Project Name Marriott Residence Inn � Phone DDES Permit # � � Address 13647 Montfort Dri.e Location Township �� tiorth � Dalla�, TX 75?�0 Range S �s� Project Engineer Ali Sadr � Sections 5 and £ Company Barghausen Consulting Eneineen, Inc. Site Address NEC - Lak� Va'ashington Phone t=�25) ?51-6?2? Boulevard North and N.E. Park Dri��e ` 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 �St�uctural M/F / ommercia / SFR Rocke Nault ❑ FEMA Floodplain � Clearing and Grading Q ❑ E5A Section 7 � Right-of-Way Use COE Wetlands ❑ �ther ❑ Other Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review Ful / Targeted / Type (circle one): ull / Modified I (circle): Large Site Small Site � , Date (include revision Date (include revision I f dates): dates): ' Date of Final: �ate of Final: ; Part 6 ADJUSTMENT APPROVALS Type (circle one}: Standard / Complex / Preapplication / Experimental ! Blanket Description: (include conditions in TIR Section 2) Date of ApprovaL '(N►�� Surl�are �'+��trr Deti�n �9anual 1/1%i � � � �i5h-l.(►(1�.�1 hl\�; t Ul V"ll _ A\ l�Hl\(; l u\_ .�l Izk _At i: �� .� I l.fZ I�i_�1�;A 11.�\t .�i_ TECHNICAL INFORMATION REPORT (TIR} WORKSHEET '� Part 7 MONITORING RE�UIREMENTS Monitoring Required: �e i No Describe: Vti'ith sll of the proposed concrete,the ' pH le�el of runoff mu�t be monitored. Start Date: Compfetion Date: Part 8 SITE COMMUNITY AND ORAINAGE BASIN Community Plan : Renton Special District Overlays ' Drainage Basin: Lake Washin�ton Stormwater Requirements: 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 SOIIS : � Soil Type Slopes Erosion Potentiaf AKF Alder�ood . ; and Kitsap Ver��teep , Urban Land i i i � High Groundwater Table (within 5 feet) ❑ Sole Source Aquifer ❑ Other ❑ Seeps/Springs , ❑ Additional Sheets Attached �(N>�I�urCair ��airr 1.)r�i_�n \1anu:il I/lili'� ? I i5h�.(N)i.d�� KIVG CnUNTY, W.�SHItiGTON, SURFACE WATER DESIGN MANl7AL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET � Part 11 ORAINAGE DESIGN LIMITATIONS ' REFERENCE LIMITATION /SITE CONSTRAINT � Core 2—Offsite Analysis � Sensitive/Critical Areas I � SEPA ' ': ❑ Other ❑ ❑ Additional Sheets Attached ' Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshdd Discharge Area) Threshold Discharge Area: name or descri tion � Core Requirements(all 8 apply) i Dischar e at Natural Location Number of Natural Dischar e Locations: 1 Offsite Analysis Level: 1 / 2 / 3 dated: September 24, 2014 , Flow Control Level: 1 / 2 / 3 or Exemption Number ' ', (incl. facility summary sheet) Small Site BMPs Conveyance System Spill containment located at: Erosion and Sediment Control ESC Site Supervisor: Contact Phone: After Hours Phone: Maintenance and Operation Responsibility: Privat / Public i If Private, Maintenance Lo R uired: e / No Financial Guarantees and Provided: Yes / No i Liabilit Water Ouality Type: Basic / Sens. Lake / nhanced Basicm / Bog (include facility summary sheet) or Exemption No. ; Landsca e Mana ement Plan: Yes / ', Special Requirements(as applicable) Area Specific Drainage Type: CDA/SDO/MDP/BP/LMP/Shared Fac. / None Requirements Name: i � FloodplaiNFloodway Delineation Type: Major / Minor / Exemption / on 100-year Base Blood Elevation (or range): Datum: NGVD 29 Flood Protection Facilities Describe: i i Source Control Describe landuse: • ; (comm.�ndustrial landuse) Describe any structural controls: '_'(Nx)Surlacr V4';�ter De�i�n ".�lanual ;!1/(K) � � I�St,-1.IN1�.�1ci� � KItiG COL'tiT�". �L-.�SN1'VGTU'�, SL�RF.-�CE V�':�TER IaFSIGti b1.�tit".�L TECHNICAL INFORMATION REPORT {TIR) WORKSHEET Oil Control High-use Site: Yes / N Treatment BMP: Maintenance Agreement: Yes / � ' with whom? Other Drainage Structures � Describe: i Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTEFi 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 ; i preservation areas � Surface Water Control � ❑ Other ' � Dewatering Control � Dust Control i � Flaw Control � ' Part 14 STORMWATER FACILITY DESCRIPTIONS Note: Include Facilit Summa and Sketch Flow Control T e/Descri tion Waier Qualit T e/Descri tion I Detention Peak Rate Std. I � ❑ Biofiltration I ❑ Infiltration � ❑ Wetpool ' ❑ Regional Facility � Media Fiitraiion MVVS ❑ Shared Facility ❑ Oil Control ❑ Flow Control ❑ Spill Control '; BMPs ' ❑ Flow Control BMPs ❑ Other ❑ Other 'i)(K)Surl�ce V1'atrr De,ign R7anual I/1!(1y -3 I i5h-3.U(1?.ti��i � htti� c��t ��r��. �� .��titii�c� tc>�. st�tzt .-�cE. ��_a�rr_k ui��ic� �t.�ti� .ai_ TECHNICAL INFORMATION REPORT (TIR) WORKSHEET ' Part 15 EASEMENTSiTRACTS Part 16 STRUCTURAI ANALYSIS ❑ Drainage Easement � Cast in Place Vauit � ❑ Covenant � Retaining Wall �"; ❑ Native Growth Protection Covenant ❑ Rockery>4" High ❑ Tract ❑ Structural on Steep Slope ', ' ❑ Other ❑ Other Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge tF�e information pr vided he e is ac rate. � i ' •' `' ` r �_ � t � � r� ° ' �-- �' tr ,. _ ; � ,�-,r�n�� , � . - --- - -- ---- _ ---- ,� � � _'(H)`1 Surtar� ��atcr l�c>i�n �1anual li I;�� i I SS(}i.(x)3..1 Z 0 N � W Q � (� � O (' J � W �- � ,p ,p - ..v••� - i -��` '� '� " N 34th St May Ge� � � _ . Se 91st 5t Park . �k �:�! •yi K. ti �31S�S[ N 30th St '' .-� .,., ;, , Se 9�' N 78th PI � 27th St � Kennydale � �ions Park � z4th St °� o` � � � m ,� �, m � � rve Zah sc � " Gene Coulon � D a � North Memonal Q ro � Highlands Beach Park � < �o Park � ro � � � , 9 n � Ne 12th St � SITE ��'�4�� , �� S t t4th St Sunsetf/ ir � � : d �Court Park � � �� a � a �� ¢' s � � : • � ``� � Ne lOth = D a � m Ne 9th St � � ' � '�' ._ A ' a, �+ oo � Z N 8� 5t Z � Hig alraknds Ne 8th St P �2tzt St < Renton �+ hSti � Municipal e � � � � tirport � ;r =� y o Ne 6 � ° � � Ne Sth P! � Z a � � Renton � Wmdsor � Murnapai �J dm St 2 � Hdls Park Ne 4th St � Airport Q Greenwoo� � Ri�ei N 3rd St 5i Memonal �. 3�� Park J A�rport ti"�'y 5 �s� N� ��°�,��S S Tobin St �� L�berty Paric Mt Olivet 4rh Cedar:�,� Cemetery �3 St S �nd St � �ver Park�, 3 � � � REFERENCE: Rand McNally(2014) Scaie F��. Job Numbet Nonzontal: N.T.S. Vert�tal N/A Marriott Residence Inn 15564 GHAU 18215 72NDAVENUE SOUTH Renton, Washington � �►1 s� KENT, WA 98032 a7 � � Z (425)251-6222 Tj't�g: � {425)251-8782 VICINITY MAP � � � : , �i1 U� �< P�' CNIL ENGINEERING.LANG PLANNING. �" SURVEYING ENVIRONMENTAL SER'JICES DATE:O9!23�14 '~%EMG�Nt P'i SOOOs'+5564'.exhibitgraphics+1556+vmap.cdr • FIGURE 3 DRAINAGE BASINS, SUBBASINS, AND SITE CHARACTERISTICS ~ � EXISTING CONDITIONS MAP �°� ~ , i `,.'�i STEIYARf%"�i.GiYR/�NTr COIWi1MY ALiA COM11171EM; �N v.;. ��..�A-?�b3v sk"-.._'. � �~ AJCUST 7. I{7=4 Ai B:Od111) � g � � ' n PORTION OF T1iE NE?/4, OF THE NWU4 OF SEC. 8, AND THE SE1J4, OF TM£ P,�� i 3 W ) SW1/4 OF 3£C. b TWP. 23 N., RtiE 5 EA8T, W. 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Y�� '�. � - i• t� .. � '� �6� " �5! *«.\ ��y-� � �.`. + .,{ � � �i,T � € . � ,ik4 r',f �,�.F �5_ �-�. � �� •� -,� �� " _ �� l y��:' �,a' NY� _ �P�% � < � i Y_ • . � ,} ...� 7�.. !t , � I i i - . �.) `- , ._� �` s��'- � '� ��_ �f " �u _ � �" �= �' , a� �t�,� �� •�' ��- . ;.: . . , . . _ . . ..- - ;� � � � � - �` �. z��. ��.� *� ��i£ • �. . . �.;sy� '��x��' *�� j s3' � i ` '�,�,� � '�_ � �� •- ... • .. . --. •. . � .. .- _ . . • � , • � . � � ' • • • •:1 �i � � � � -s • � 1` . �� - • 2.0 CONDITIONS AND REQUIREMENTS SUMMARY � � i�- 2.0 CONDITIONS AND REDUIREMENTS SUMMARY The following is the analysis of the Eight Core Requirements and Six Spec!ai Requ��ements as delineated in the 2C109 King County Surface Water Design 1�lanual as modrf ed by the Ci?y of Renton. 2.1 Analysis of the Core Requirements Core Requirement No. 1: Discharge at the Natura!Locatio,�. Response: This project will continue to discharge off the weste•n property line cf the site, as it does under existing conditions; however, under proposed conditions that sheet ffow will discharge via a pipe system from the area to be developed and the contributing upstream. The remainder of the site w�ll continue 'o sheet flo�� off the �vestem prope�y line. Core Requrrement No. 2: Off-Site Ana/ysis. Response: Please see Sectian 3.0 of ?h s Te:,hr�cal lnfcrmation Report for the off-s te analysis prepared for this project. Core Reqwremer,t No. 3: Flow Co,�trol. Response� Peak rate `lov�� contrcl �s the standard for this p�nion of tre City af Renton and that �s what is used here. Core Requirement No. 4: Con,veyance System. Response: The conveyance system for this pro�ect was s�zed in accordance with City of Renton standards. The Modified Rational Method was utilized with a 100-year precipitation, a Manning's 'n' value for the pipes of 0.014, and an initial t�me of concentration of 6.3 minutes. See calculations included in Sec?ion 5.0 of ±his �epert. Core Requirement No. 5: Ervsion and Sediment Control. Response: An Erosion and Sediment Contral Plan has been prepared �n accordance with the 2009 King County Surface Water Design Manual as modified by the 2a09 City oi Renton Amendments. A Stormwater Pollution Preventior Plan !SWPPP} is submitted herewith. See Section 8.0 of this report. Core Requirement No. 6: Maintenance and Operar�ons. Response: A Ma��te�n^ce anc �pe-at�o�� Pian �s �ubmi,'ed hF�e��h See Sect�:�r 'G.G of this report. Core Requrrement No. 7: Frnancial Guarantees and Liabilrty. Response: This project will concur with ail �:';� ��' Re��t�� in �� c�a� �c_ara�;ttcs ��d liability requirements for projects of this ca+,:�� Core Requirement No. 8: Water Qual�ty Response: This project is proposing a � , � .. . . � '�.'.':; .. Enhanced Basic Water Quality Requirement Menu as required by tr, � ;hp ampn^!mpntc +r thc 7r1(?O L(in^ �;�i.Jnf�' �L;'4a^P��'ar f1Fci�7n �/!a,. e 2.2 Analysis of the Special Requirements • Special Requirement No. t: Other Adopted Area-Specific Requirements. Response: There are no known other adopted area-specific requirements for this area of the City of Renton. Special Requirement No. 2: Flood Hazard Area Delineation. Response: There is no Flood Hazard Area associated with this project site since it is so much higher than the surrounding ground. Please refer to the FEMA FIRM Map contained in the off-site anal is section of this re ort. YS P Specia!Requirement No. 3: Flood Profection Facilities. Response: This project does not meet the requirement for flood protection facilities since it does not rely on an existing flood protection facility nor is one proposed. Special Requirement No. 4: Source Conirol. Response: Applicable source control methodology will be applied to this project, which will include, at a minimum, covenng the trash enclosure and sweeping the parking lot on a regular basis. Specia!Requirement No. 5: Oil Control. Response: This projeci dces not meet the requirements for Oil Control since it will not � exhibit high-use site characteristics nor has it in the past. Special Requirement No. 6: Aquifer Protection Area. Response: This project site lies in Zone 2 of an Aquifer Protection Area and therefore, no open ponds or open water quality features are allowed. As a result, this project is aroposing an enclosed water quality feature known as a modular wetland system. • ; '55h» "iDh doc X. ; , i� . - � � � � J Q Z a w � v� � � O 0 M i LEVEL 1 OFF-SITE DRAINAGE ANALYSIS Marriott Residence Inn 1200 Lake Washington Boulevard North Renton, Washington Prepared for: Western International 13647 Montfort Drive Dallas, Texas 75240 F September 24, 2014 Revised March 31 , 2015 ' Revised February 23, 2016 � Our Job No. 15564 i I i G H '`� C� Q n► � mZ - . .. . - _� r � .;�i;'a ;"rF „�. • .�, .. ."LR .,. • ..i"�_ EE:,I,-- �F; • �_. . ,,� ;.r+ • i;,•,� J't'_.. Z ? ~�n:vh bargnausen com 3L ,��' A' t r `p '4. ..t. c w;, �r TABLE OF CONTENTS TASK 1 STUDY AREA DEFINITION AND MAPS EXHIBIT A Vicinity Map EXHIBIT B Downstream Drainage Map EXHIBIT C Upstream Basin Map TASK 2 RESOURCE REVIEW EXHIBIT D FEMA Map EXHIBIT E Sensitive Areas Folios EXHIBIT F SCS Soils Map EXHIBIT G Assessor s Map TASK 3 FIELD INSPECTION EXHIBIT H Off-Site Analysis Drainage System Tables ? ' Conveyance System Nuisance Problems (Type 1) 3 2 Severe Erosion Problems (Type 2) 3 3 Severe Flooding Problems(Type 3) T�SK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS. INCLUDING WATER G�UAUTY PRUBLEMS 15564 00' doc � � TAS K 1 STUDY AREA DEFINITION AND MAPS ZZ TASK 1 STUDY AREA DEFINITION AND MAPS The proposed Marriott Hotel site is located on two separate parceis o# land which total approximately 2.89�acres in size located within a portion of the Southeast quarter of the Southwest quarter of Section 5 and of the Northeast quarter of the Northwest quarter of Section 8, Township 23 North, Range 5 East, Willamette Meridian, City of Renton, King County, Washington. More particularly the site is located on the east side of Lake Washington Boulevard North and lying northerly of N.E. Park Drive a.k.a. Sunset Boulevard. I-405 forms the project site's eastern boundary and there is currently a new hotel going in immediately north of the project site soon. The existing topography of the site is such that the site consists chiefly of steep slopes coursing from I-405 down towards the right-of-way of Lake Washington Boulevard North, which limits the area on the project site that can be developed. The total area of the project site to be developed is approximately 1.17 acres. City of Renton maps were used to aid in determining the downstream drainage course from this project site; however, the area immediately adjacent to the site between Lake Washington Boulevard North and the western property line of the site is being used at this time as a consiruction staging area so it was difficult to determine where the existing catch basin was on that portion of the site. Approximately 140 feet of sheet flow is currently draining from the project site in a southwesterly direction toward an unfound existing catch basin near the Burlington Northern Railroad tracks in the Lake Washington Boulevard Narth roadway, which then drains in a southerly direction and ultimately southwesterly again, and then northerly into Lake Washington. Please refer to the Downstream Drainage Course Map and Off-Site Analysis Drainage system Table for a complete description of the downstream drainage course from this project site. The proposal for this development is to construct a large hotel with accompanying parking garage and parking lot located in the northwestern corner of the property. UPSTREAM DRAINAGE ANALYSIS Based on the site visit and analysis of the upstream basin, there is a portion of forested land that does flaw onto the project site totaling appraximately 0.45 acre of land consisting of runoff from the right-of-way of I-405. This runoff will be collected in a perimeter conveyance system, bypass on-site flow control and ' water quality facilities, and discharge via pipe to the proposed conveyance system in the right-of-way of Lake Washington Boulevard North. There is no other contributing area from the north, south, or west on :his project site. I i i I � ; -,r� ,-�;i ._,_ i L� E�CHIBIT A ''� Vicinity Map � I T � v�� " N 34th 5t May Cre� � ��;� _ Se 91st 5t Park :t. `1 �31 si St . a�'-• � N30th5t `'�._-�� Se 95' N ZBth PI . �27th St - .� Kennydale � Lions Park � 24th St � ` � o � � < �o � N � l/� � Ne ian st � '° Gene Coulon � � a ? North Memonal a A � Highlands Beach Park � c � Park � ,� � < �..: -.: , ..:._ . ,� 9 � Ne 12th 5t 'Y� SITE '� �. �y�� .� S 114th St x �'i� � Sunset,r"% �- d ��Court Pa�ic � ✓' 7$ � �1 Q °° � �� 3' � `�'� � ¢' s > �� - � - � D < Ne 1 Qth � � t A 4 � L - `� � Q < L �3� ; A m NP �IIf1 S� a0 � : °' e �. _ Z Q, °O : N 8eh Sc � H�g al�nds Me Sth St z P 121st St � Renton � hS< � Mun�ci�al e' a � �� o Airport q ;r � �, y T Ne 6 D .-.� � � � 'Ve 5thi PI > Z D � � Renton � ti^Jindsor ? Muniupal N dth St Z � Hills Park Ne 4th St � Airport Q Greenwoo� � ��'�'�' N 3rd St 5� Memonal � �� RJV�'/ 'yi `ye 3`t� Park Afrpon Wy 5 �'� '��Ave S 5 Tobin St �� Liberty Park Mt Olivet 13Q�� St Cedar:_,` Cemetery S 2nd St 9� iver Park>� .�� 3 � a REFERENCE: Rand McNally(2014) Scale: F�/': Job Number Honzon�ai. N.T.S. vert�cal. N/A Marriott Residence Inn 15564 GH'�v 18215 72NDAVENUE SOUTH Renton, Washington � n► �� KENT,WA 98032 C] � Z (425)251-6222 Title: � (425)251-8782 VICINITY MAP � u o r s �. ,� P�' CIVIL ENGINEERING LAND PLANh�NG. ��Y�EHG�pE� SURVEYING,ENVIRON�dENTAL SER'vICES DAT :09123/14 P:'+50GOs 15564tiexhibdlgraphics'�15564 vmaF cdr � , - � EXHIBIT B Downstream Drainage Map Cit of Renton Print ma �Tem late a1 Legend � y p p I I Ciry and County Boundary _ _ __ ___ - — -- _ _ _.__� aner - - -- __ ----- - - � - � � �. ai�� z IAA��. �. �� cay aa Rerno� >. - . - * � . � � _'g _ 1•-3_ _ � .. f l ' �f � � - �'-�� '�' � �� Addresses � 2 i t it�'� � � �R . :?'�-.�_ -��Si 1� If' ParCels ! � � ,; � s, �� _ _ 6 � �; � a '.��`� t �.rt-�,.�. ' �� ,st F�oor ! � �� , � '� � - -_ _ s i�� ,.�� • � 1st Fioor � � � � '� � 'f �}.,� '� 1 �'_�Y � �� ►�� 2nd Floor �� t t . �' - _ u� �-'� _� �: _ �1r. I Li,=-'��``.'�"'�-�__. � 1stFloor � .- �� +�"'Ry�" �t.,� iAq� '�� ,-�`- __, Other Bui{dings ,� ��-i; ��3� � •_ �. 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'�� , � � . ,� � _.�,�.�'�rt' ` �1___._.1�- � �- r . - , �� _ =�_ �:S �� _ �,�€��`$ __.� -� - = - - " ' t . .. . � , � � -- - _- Information Technology-GIS J This map is a user generated s2at�c autput Trom an Irtemei rnapp:r.g ;�te and ' � ' is for reference only. Data layers that appear on this nap may or may not be City Of 512 � 256 512 F�t RentonMapSupport@Rentonwa.gov accurate. currert. or otherwise reliable. — On -' ' ! WGS_1984_Web_Mercator_Auxiliary_Sphere 09/23/2014 THIS MAP IS NOT TO BE UScD FOR NAVIGATION Finance & IT Division� ✓ EXHIBIT C Upstream Basin Map ?,�( C i ty of Re n to n P r i n t m a p 1'e m p I ate � L�eCity and County 8oundary � ------- _ _ _ _ __- ; � i ___ _____ ___ ___ ___ -- _ _ -� _ - - �' _, �� a� . ----�r�. ''. c�ry a Rernm, ''� �� , �� . , .�� l.. Addresses �� - � v�p i y� � 1-Z �_� � , '"� � � �t Parcels i ' '� F, ` , . � 1 st Floor : r,-�., �� /.R. -��. . � ,� . _ � . �. i �� ,.. 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Data layers that appear on this riap may or may not be , � Cl�Of � I 512 a 256 512 Feet RentonMapSupport@Rentonwa.gov accurate, curren' or otherwise reliable. I , On ''',' WGS_1984_Web_Mercator_Auxiliary_Sphere FinanCe & IT Division _ 09/23/2014 THIS MAP IS NOT T�BE US:D FOR NAVIGATION i �, � � � TAS K 2 RESOURCE REVIEW Rl�.; TASK 2 RESOURCE REVIEW • Adopted Basin Plans: There are no available adopted basin plans for this area of King County and the City of Renton has already indicated that Enhanced Water Quality is required for this project site. • Floodplain and Floodway FEMA Maps: Please see the enclosed Exhibit D - FEMA Map Panel No. 53033C0664 F dated May 1995 that indicates the project site is not located within a floodplain or floodway of a stream or a river. • Other Off-Site Analysis Reports There are no known other Off-Site Analysis Reports performed for this project site. • Sensitive Areas Folios: The City of Renton Sensitive Areas Folios were reviewed for this site and there was a sensitive area covering most of the project site which consists of erosion potential. Please refer to the Sensitive Areas Folios on the following pages of this report for a complete description of the sensitive areas on this project site. • Drainage Comp/aints and Studies: Since this project is in the City of Renton. tr,ere are nc icno�•rn drainage complaints from King County associated with this project area. ' • Road Drainage Problems This is not applicable since the City of Renton has not indicated there are any drainage problems associated with Lake Washington Boulevard North. • United States Department of Agriculture Krng County Soils Survey. Based on the Soils Survey for this portion of King County, most of the project site lies in A�dervvood and Kitsap soils, which are very steep, and portions of the small remainder of the site lie in area des�gna;ec �Jrban Land • Wetlands lnventory Map: There are no known �.vetlands on the Froject s�te based on C�?y of Renton maps. • Migratrng River Stua�es: Th�s �5 rc�� uppl��cable s�nce th-�ere �s no river c^ cr rea� ih��.s s�te �ased cn City of Renton maps. • Adopted Stormwater Compliance Plans: To �he best ef our kno�vledge. we are nct dware ot any adopted stormwater compliance plans applicable to th�s s�te. '55E�0�1 aoC � I � EXHIBIT D FEMA Map , � � � ` � LEGEND � ` '`� ', %, OTNER �REAS iZ"t � � zONE x Aress detrm�nee te, or ciuule caz-r�•... � �� (,`, kr..ip��ain � ,1 v ,� T t �i �� `,1,\ .C j r.. : z <�.- � ZONE X � c � - t ��i � �� '.:G ��JF :.p� ��. r O ,� p � � C, I ! � � r� . �,,. \ � . / �i G � % �+ _ i -- ; tiE 1dTn S��F�.u- � 1 :) �4,� ', � � ' ``�. ; SITE �� ' �� v � , � 4`�/: ' � r � .;�.T��y r i ' . A � i % �� l\ --__ . ---- ' - --_ _._ -- -- --- - ___,.._- ---- -__—__ ' AQ�S� 'I �� ,� � �'�'P , ._ `� _�C :;^ � *�� 9 `'` � 8 � .:� �1- - �.. y� �" -l1C REFERENCE: Federal Emergency Management Agency(Portion of Map 53033C0664 F, May 1995} Sca�e FO�: Job Number Ha�zontal: N.T.S. Vert�cal: !�U/1 Marriott Residence Inn 15564 �,�yHAVs 1821572NDAVENUESOUTH Renton, Washington KENT,WA 98032 m � 2 (425)251-6222 Title: � (425)251-8782 FEMA MAP n � c = t � ,� �� CIVIL ENGINEERING.LAND PIANNING. '`ti�Ew�„aE� SURVEYING,ENVIRONMENTAL SERVICES DATE:09,�Z31'I4 P'�15000s�.15564texhibdlgranhics',i5564 fema.cdr � ^ , ,,r'� EXHIBIT E Sensitive Areas Folios a �� • � ; �� # �� : ... �~�- �� *� . � � �,_� �f# � �� llt�i �. ��t� ..... .. �� : ,', !a� _ �� Q I �� `1 � a II i # �� • � I � � I ♦ � i * ; � �t� ! � � r� ♦ � ♦��+ � �� '� StTE� `�'P� - ��r��ta�ss� -_ - � � �� . � 4 ' � '.�`�r .. K:. � .,� �` ...' ay,�:,� y , � r, � �a F''}�� ... k�• - G:'. .�i ;� � _ Nu=-z. �. >- • .�� . ,. .{4 � ��ti� � � . �'""'�`, t� .__ _ -�� `` ' � ,4� . �..,...# i� : � � . � ` � �;- . � � '�.. .� a ' , � j� ` � __ ,� . : � ,i• �=1 - �� m_ ___ ..«,.�.� :�� a ;; - �, �� _ ��" � - - __.� � � - , :. �:� t - � � � _. -cA-�;�a�-.,...;_ �y,._ . `.-. ° '� _, `_.,= Aquifer Protection _ `___ � ��:�, 3 - � `�.:� Zone 1 ' "� � � Zone 1 Mod�ed ` � ��, y4 � � Zone 2 , . _ . . - _. � � : • REFERENCE: City of Renton{2014) S�: FOr: Jab Number Horszontal: N.T.S. VerUcat: WA Marriott Residence Inn ¢G H A�s 15564 18215 72ND AVENUE SOUTH Renton, Washington �• TYt� � KENT,WA 98032 4'� , �Z (425)251-6222 Title: _o � 4 (425)251-8782 AQUIFER PROTECTION : j�' ? ��r �` P° CIVIL ENGINEEi21NG lAND PLANNING. MAP "'ro�E��,,.E� SURVEYING,ENViROt�AENTAL SERVICES DATE:02I17t16 P:t150pOs4155b41ezhibitlgrsphicsi15564 renton-sens_cdr ^ f� � r' � • # � �'.� ,l t �L....... . • .� ' . � ' �'`�. , t, � . . - �.,�. �f � • •� r.._.. �,�� - ____ � ; .� � �� R , ""� , . � 1 : �y � � t . 1 �� . . � - �.!' � !11 s ,�`� - .�� F� �,'� � � SITE� ' �-•�'�.. .�. �� ,,,,,»..... ...• , � � , . 1` �:� � _ � � : _. �; � ; . � . _ - . � �--�.�� i°°l - r�� '�� _� � 1 - _� �� iE�� " . ��a��`.' 1�L "� - � I � � �� _ � � ' � � 4 � � + ' - � � _ ._ t_ � � �� .� � w , � t . a ' 4!+!� ' � �' ` . , ` -. -�.4..` ..--.,......__.,- s .�E _ � � a j �� l . '• . - _ r . �� ,r: �i.eFKi t1�•. - �G� . . _ I � . .. �_ „u.3 �,� �' . ' . . - � _ � � — I � ` � ..-_'___.."'�M�- - - _...�-.�7 � ' e.� � . _��_ Coai Mine Hazards * _ Sevcrity _ � � K Hk�H — � �. .- MODE RATE I � � � *��-� UNCIASS�FlED - ;� � �..�✓ � � REFERENCE:City of Renton(2014) Scate: FOr' Job Number Honzontal N.T.S. VerUcal. WA Marriott Residence Inn 15564 �G~A vs 18215 72ND AVENUE SOUTH Renton, Washington Q n►� � KENT,WA 98032 m � , Z (425)251-6222 TrtJe: � (425)251-8782 COAL MINE HAZARD F� �J�' e? CtVIL ENG�NEERING LAND P';.ANNING, MAP C''ti�'ENG��E�p SURVEYING,ENVIRONMENTA�SERViCES DATE:02l17l16 � 15000s*5564texhibit'�raph�cs"5564�nfon-sens c0� � , �'� : t ;��. , _ �� . � � � �� r � . � � �� __ ,_ s 4� �,-- .,�♦ � �„Y �.,-�--� � . � . '�..,,. �..... �,� � _ _. - •� 1 �, . R .,� � . '�`�� , � _ . � . � . � i . , t �; � s a � � � _ � �.� . 1 !` -� � . a ,,�--_.__` �� .��'' �. � .�........�.� SITE G � �r_ -�,- ; � ; �-- �� ::,,,� � � � q : � ��- � � �°°� - A�. ;.,..fi,�i � _ i� � � �� . �........a� � � p! � � ,�-. . . �� _ . . �� " = ...,..� :g�' � � ,� _'. �` `� � q a� ' � ^i y��£y Sf � _ - e-s�- . �. � �...et�_}d .LL - . . ,., � . '.k..._ . � . � . . � - �� - �-�--- Erosion Hazard _ � IP'il ;n � � ; ` Severit _ _ - : `� ��.- y _ _ .�_ - = _ �,. H��n . ;�,� �� . � � . -� . . �� " REFERENCE: City of Renton {2�14) sce�e FOl': Job Number Hwizontst N.T.S. Yerf+cal: WA Marriott Residence Inn 155fi4 GH A� 18215 72ND AVEtVUE SOUTH Renton, Washington Q 1T►�`S� KENT, WA 98032 Q� - ` ��Z (425)251-6222 Tit/e: r � (425j 251-8782 EROSIQN HAZARD °` �i�'' �? l MAP �r ��- CtVIL ENGINEERING.LAND PLANNING DATE:OZI17I16 ro�€N�t,a� SURVEYING.ENVIRONMENTAL SERVICES P'15^�Js�55&4;exn��qraphics'�5564 renfon-senscd.� � .� n f' , • � .-y � � � �' � -�� '►1�rt` �.t�t;'ek � � � � ��• ,� _�y��_ -_ ti4ay C reek P a ♦`'� 'i ' c' ry . , 1`_.� 1' `� ; Z.� 'i ` "_ l 1 . ,-. �� t ► � � � ' � �- � � � � � � � � . � � � � 1• , � � '• C � /,` q _ .�� . _ � ♦ , i`� ,t � � SITE `` � f ..---•" �* �` ;.+..:. ; r i � --��.� � f a T �' H ighl: ��+ �� `�. r �, ' 'y N 8T 5T � � � � ' � �F7TH 5� r-•�� " ! z � ��`� 67'N ' � f � � ��__ Z _ � _ __ _-� C 4:, �� , ; ; � `_, � 1'� ; � .• � I �- � �` � t . �....�-.�_..� e :.`.. } � �� .�.:.�......._.. _ -�' � ��,. � 3RD `�` s_'4a. =v �'*� � �.-�•""�G��.. ,��" � � � ` � �-v� '_ ��i _ ; �� - � - - � � LpinA . . .. . � � .�i�w""".�y�"" ��'�'' _�e-.4 .� Y L1 - <' � �`� / � _.- `-e F c- r...q��a.a, . -'` - i r' `'��G�H;� �� •,�.u.,, 1 ' :� Y REFERENCE: City of Renton (2012) Sce/e. FO j' Job Number �� N.r.s. va,r�: wa Marriott Residence Inn 15564 �H A V 18215 72ND AVENUE SOUTH Renton, Washington m� n1,F KENT,WA 98032 - ` �2 (425)251-6222 Tltl@: ` (425)251-8782 FLOOD HAZARD � , j � � ��' e' CIVIL ENGINEERING,IANd PLANNING (r�NGENGyNE�p SURVEYING.ENVIRONMENTALSERVIGES MAP DATE:02117116 P tSGOGs''S56d,exh�brt,Q�ac�hres'�556�renton-se^s udr � ,�"� �� `r � � � r+ . . �*1�1M� .. _ . �� -` £ �r ,,.,,�,� # _ � � �` �__� `•� _ _ � ; �. �.� �. :. � .+ � .�� rss�s• �y* ` ` , �� + , � � � '� � � '••i � ! � �. . _ �. . � . 1 � � � . � , � � ' � �t • , , � ` • i..�" . w � . '� �"� y , • �..�---- . �� i ,,,��<_�� , ,�' ; � �f� f � ��„r,,,�..,�.�.: SITE , r `'�" �` � �,- _ �.: � �,.� � _� _ . k� � _� _ � _ � _ � , _ �q � �� ;- � � . � �; ,� -�_ . �� y; . �. _ Y� — �al . � � ..r � - �°'� I � `� � , . _�a.- � �'- � ; �_ ,} _ , - „�,► ; e , f � ....,.,� � � =z � xi� _ ;� ��. 4 . . ^ .a � ` � 'F `: ',,,r' 1�'.. ,: ��. ,�_.—. _ . : .ti .:�� . .. .._._._,�,.-w'� /+ � + �� 's,, .: ._, -�.�--._ .. -....,v_. �- 1� � �� _. ....:_ � � , �fF '� ➢ . '__" _.�� . "-.�i=.�.��m. .. � ..y;' . "` � .. ; • landsi�de Hazard � ,- - -t ___ �: . � K r�r fi rit x � c �� `�' '�-- � Very H�gh , , _ _ -� � y � H�h �. _ _ ' e - f� Moderate � _ � Unciass�d w t ' � .� .: � . .,. � REFERENCE: Ciiy of Renton (2Q14) Scere: F�/'. Job Number � ".TS. ��: "'" Marriott Residence Inn ��H A�s 15564 18215 72ND AVENUE SOUTH Renton, Washington mT�►� F KENT,WA 98d32 - -, 2 {425)251-6222 Tff1G': o . ��r �a2s>25,-8'$2 LANDSLIDE HAZARD _� ��i►► � tr fp CIVIL ENGINEERING LAND PtANNING, MAP ti�E��,..b SURVEYING,ENVIRdNMENTPi SERV}CES DATE:02/17(16 P:;1500ps'155641exhrbifsgraphres�.i5564 rentai-sens.�r - �� i � � ! �,.'; j4 's`� . .,� � • �` t " + ... ' p��,,,. �; � . . i�� '�`�-� `�.�`'• , ' .. ♦ �<'' 6�* �. . f s " �"_ . .F:. �.. � , .:. . #�# . � � ��,_ �`��. 7 .;�:. �ti._..... �" ,�tf�� £ ��< _-'*+-�.�.._.�,__. # Y ` �.-' f ♦ � � � � � « - � - _ . �.� : � ,... ' '',► ,� _ � i . ____ �e . � � ' . 1 ° ' � . t' . « - .�� . � , � �� ,.� � � . � � �� ,..,�,�.�..,.:.•` SITE � -� ,y� � � � . � � .. . - � �. �. 1�' . . .... - � P_"� a. a . � - "`-��.� � _ �.�_ . ,., _ � 3 - --r-' - . � - # �� 4�`� - � :i: `:"i� ' �, * � � ..: � ., �� . � R'�� i • : ;_ � �.� � �_� �� # _ � � _ - ,.. `� �� .*.,�t � ,� v � � _ R , F _ : e3�:e'3�# ' `� , s i .. . .� 6 � � . �' .-v,-..Xr.>.,E`. ` .' �� '�� +� ..-. _ _ , �}� �`3 � , .3 s, ��, $ k s�PE . A �� • � �� 9`L s .< <..� 'u ��'. � £ � f . .� `� §�.. j_. h.. � :# . . � `>�'. - . `� � �" ` �Y-. ,_,�� !». ,��.�� - �: � ` � Steep Slopes � ., i = - . � �. �� __:._ ,; �-s-, �`�,_ ' Percent Range m_._m__ ._ . .; �" ,,,_ - . . >15%�<=25°�c . � � �.,.� .. >25%6<=40°ro r....j ` . .. � �, i.v � : � '`� >40 A��-90 R _ > > ; �. �. _ - � �9090 � � ��w . , � >. . � , 3 , � - ., �_, REFERENCE: City of Renton (20i4) Scale: FOr: Job Number Honzanta/ N.T.S. VerGcat: WA Marriott Residence Inn ' G H A� 15564 , � s, 18215 72ND AVENUE SOUTH Renton, Wc']Sflfllf�tOfl 1�'I KENT, WA 98032 � m � 2 425 251-6222 '' ( ) Title: � I r • � (425j 251-87$2 I 1 j`'� ? STEEP SLOPES � CIVlL ENGINEERWG,LAN�PLANNWG. ��V t I �''a�EN�,H6�`4 SURVEYiNG.ElJVIRONMENTAL SERVICES MAP DATE:02/17/16 P:1!50Dpsi 15564tea�ihitigraphicst?5564 tenton-sens.cM � Q. � � � �"' � m .� = O � � W � U � 4 � � �� , ..._..a.._. .__.. * . . i :. ��t , . � �' '� � ,_ � b . . - �; _ , �� ., �` � � �_� _ _� . � � � �� -� � . � , � t r , � ; :� � f_� � '` � ��;�� 1 � � ;� � � , � q� . � " ` � �� , � t , � � {� � _ Y� �� y �` � �� .� q"y - �`� �� . _ ,, � + . ,.: :� ..;�-� ` � ` �`- m .-v. _ . _ - _� ' �� ° �., _._ ;�_ . . ,. �� ;. . -. � . .. + � � �� ' - ., . .. - :�. �t'� � .. : -.� -�._ >: . -:, ;�. #�-: � � � �.�.=a ;�" •_ ' :� � . � : F. � , � � �. � , �- � m . � ``i il, , � , � . — . � I V i'� � - � �� - s � ,�� ,. 3 � ;- . 0 _ . . ,� ; . ��, ; � r, t f _� -�� . ��, � �. �- _ � - _ , � � � i` b ` .� "'_ . _._ � . I I vz'y^ . . �� .-.�, .,.y f �_ _ � � � ` A � T � � II 3�� `.:: , � �§#: �� ..t, � r� !fi . `.�`�._ _ 5 I .�-`��2:a '=:_.� . � "" � :-as.. � �t;� » a} � ` �.._ •�`sc - � ._ � x A� ^ .' ,. _ � $ � _ � � _ ' > � � ` �- � �-�-� �� '�� -�� t _ . - � � „„„e �� `�.,;_ _ � � � -�`� - _ �" � =' �� 5 =. ��,�� e `` _ +� �' '° �,� � � g: a�.� �' �� '�r� �'��.�� 1 ` �``': # �� -', i - �. +��,,.# '; 1�� . }_� �� , -- • '� � . �''. �-t'� � f� �. �..'e � #�: ��: ��: � '� � ._ �_ .� % �_�: .� '�} . A§ * ._ag:- 4. _ '�. _.. ; ,r,,# �',... . � s ». .: :'�� .... ' .. .�'�� e .. . '-'. �- . .� ,.r..� . . :_.- � n _ -.� .�_ i+� '�:.. �; .ur�i � .... � u�-� = vu�r �errice LEGEND: AkF =Alderwood and Kitsap soils, very steep Ur = Urban land ��a,Q Far: ��,�m�� a:�Z�ta! N.T.S. Yerircal WA Marriott Residence Inn ��HAvs 15564 18215 72ND AVENUE SOUTH Renton, Washington Q- 1�t tn KENT,WA 96032 II? ; 2 (425)251-6222 �Itf�': r : � {425)25i-$782 SOfL SURVEY MAP a P� �ij�, •' CIVIL ENGINEERING-V;ND PLAh'NING. tT�hc tNGt�aE6p SURVEYfNG.ENViRONAAEN�FL SERVICES DATE:09�23i�4 r -. _�5a o ��,t-ar�. .� c�s6a sod.cd� 1 � ; EXHIBIT G Assessor's Map �� , �Y}N � _ . , `'� , ..n � _ ' o . � ,.. ' . '. .1.. . W �\ ., a , '� � , � '� � - '�. . ' � -, "' "._"�'."'":!1.. . ..__._"."_ ME t6'n . . , `` . _____ _ _ _ _ _ '. _ _ ` ' 4 �, �_� �= , . ,� �j'._ '. � , .S i � . ' , � � � , �.4 , '� � ,1, 3 , -'�'Z . . �`, ,' � _ . , _ � .` '�. �- ' � , ' 1 - . „ _. __._._ _ . � p ....t i� _ �._'� , � Z " ` , . { ! , f' ' _.�4 .. . ' .. , �1� O .,�4'�.� .._re - , ��Z . . .. -- � i t .. �:��? ` . ' i � .'��'��. ' ..- �- � ' � � 1 � •4�� #4 � ' f _t.. . _ .�� ... -� �� . . _ ; MEM V]K�4 .� - � ... � - - _,'�, ' - � ��Y ' . . • .. 110)]Of001 , �� 11 •.11� �d: . , .m /'; .\, • r.- . '. ` �Z �'�i ' �� ' 1�. _ ,. • �i:�_� , 1 � � '"� � �p ' . �.t:' � . _ , �p , '�r.• i . �'- �'•�, �''•. . i '. �•. ' '• . � . , , .,•' .' .' ,i' y_ 1� . " _ ' _ . . i -_ •. •.. . : �. ; . i � �• 'ti •. .. .. � �. . . ... _.___.. '-x ' � . ' `� ,t - i i _ _ .,`'- �-- .�_ 1 �1._ , _.. `_ �5` _... . , * � � - $ '_._ _ _ _" _ _ ''• � , ' .SE�.n � ''A - '�� '.�.. E i. O Z. -.�� .y " i . _ .� '!� Y = _ t r - ' � � . � �p Y5�� r2(� _ ' �.. • � '��`.� � . . . . ` Qg - �.[7. . . ��' '�� i ._Q � � � . t; ' . ` ` �� S .��- _ �I 4r ' . R, ,`11 `,�; . ' �'I `� ; ,,' . •-� . .. 1 ; ` . `•� 1 � i ' . '-.�f � , . . . 1� G • i ' 1 . � �` �` �,. � . , i r 1t 1'� •��! '. , � I . �...� � 1 • 1 i'/ � • : �, 1 . . ' �• '1 11 � .... . .. . . . , ' .� .. .«. .. .. � ` � . , . .. . . ; . . 11 . � � • � ,� A a .�.n s . .-:[ � 1 � 1 � � � : a�.�• 1 1 � i 1 . 1 1 - . . 1 � -�J�L'___ __ , 1 ��' � . �-�.,. � � • . .�T' � ,. , ��' _ � • ' � . -�� ,'� �� . , � ' , __..._..._..._ ........___",�.._'__..- . . ..... ..._- ,.,. -_• � T ' ,' ', � R�451� ti , 1 � ' ' , , � � .....6�C i` , , .. REFERENCE: King Counry Department of Assessments(Feb. 2013) S:a�e FO/: Job Number Nortzonta/ N.T.S. Vertiwf N/A Marriott Residence Inn �GHa vs 15564 18215 72ND AVENUE SOUTH Renton, Washington � �►► � KENT,WA 98032 ln - � Z (425)251-6222 Tlt�e: �, � ca2s>25i-a�a2 ASSESSOR MAP o i 2 � , �� CIVIL ENGINEERING LAND PLANNING 'tic�ti�,M�� SURVEYING.ENVIRONMENTAL SERViCES AT :09123�14 P,15000s'155641exhibitlgraphics�15564 amap cdr ��( "\ � � Z 0 � M V ', W � a. '� c� cn '�� az �- - , 0 J , W I � EXHIBIT H Off-Site Analysis Drainage System Table (�1�l�'-�1'1'H: ANALYSIS Dl NA(;F, til'S'1'LR'I TAEiI.E Surface Water Design Manual, Core Requirement #2 li;�;in: l.akc �'.�shin�l��n Subbasin Namr. Subhasin Numbcr: Distance Obser��ations of Field Inspector. Drainage Component Drainake Component from Site Existing Potential Resourcc Revicwer,or ti��mbol Type,Name,and Size Description Slope Discharge Problcros Problems Resident Cuns�nctions,undcr capaciry,pondmg. Typc: shcct Oow,swalc.,trcam, ovcrlupping,flrnxiing,hahitat or urganism channcl,piFxx.pond;snc. f)rainagc basm,vc�;rtauon.covcr. d�wtrucnon.scounng.bxnk rloughing. l nhutary arca.lil�clih�xxl of pruhlcm. tirc Map diamct�v,surfacc arca Jcpth.typc of xrosiUvc arca.volwnc "ro I t. scclimrntation,matiion,othcr crr�sion ovrrfluw p:unw�Ay�.��uHi��„�acts , I Shcct flow From sitc ovcr gravcl to catch 3.5 0'-140' Nonc Noted Nonc Noted basin 2 Catch basin to manhole 12-inch pipe --- I 4O'-330' None Noted None Noted Catch basin and manhole coulci not bc f iiund duc to construction aclivity. 3 24-inch culvcrt To wctlancUchanncl --- 330'-530' Nonc Notcd Nonc Notcd ('ulvcrt cauld not hc fi�und. 4 Ponding arca Wetland Flat S30'-SRO' Nunc Notcd Nonc Natcd S Twin 54-inch RCP with Undcr Lakc Washington Flat SKO'-655' Nonc Notcd Nonc Notcd twin 4R-inch RCP culvcrts Boulcvard North 6 Opcn channcl 10' - 1 S'dccp, 10' bottom, 1:I �.1 655'-755' Nonc Notcd Nonc Notcd sidc slopcs, thickly vcgctatcd 7 R4-inch RC(' with 54-inch Flows undcr railroad iracks 0.1 755'-ROS' Nonc Notcd Nonc Notcd RCP 8 Opcn channcl 15' battom, 15' -20'dcep, Flat ROS'-985' Nonc Notcd Nonc Notcd tlows norlh 9 Largc culvcrts Undcr road, flows north 0.1 9K5'-1,049' Nonc Notccl Nonc Notcd 1 U Open channcl Flows into Coulon Park Q.1 l,049'-1,149' Nonc Notcd Nonc Notcd I I 'I'hrcc 54-inch CMP Undcr Coulon Park cntrancc O.1 1,149'-1,225' Nonc Notcd Nonc Notcd culvcrts road 12 Open channcl Through Coulon Park to L,akc 0.25 1,225'=2,175' Nonc Notcd Nonc Notcd Washington -`L-- �::�,.�un��I��, � TASK 3 FIELD INSPECTION There were minor problems reported dunng the resource review, however, the field reconnaissance did not find any potential constrictions or lack of capacity in the existing drainage system p�oposed to be utilized for this project site downstream from the project site. However, one catch basin and one manhole as indicated by the City of Renton COR Map could not be located, but that was because the area that the catch basin and manhole are located in was under construction due to gr�nding N.E. Park Drive east of the site. This area downstream from the project site was be�ng used as a staging area for that construction. 3.1 Conveyance System Nuisance P�oblems (Type 1) Conveyance system nufsance problems are m�nor but 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. Based on the resource review and site visit, there is little evidence of past conveyance system nuisance problems occurring. In fact, the entire downstream drainage course appears to consist of pipes sized adequately for the flows contributing to them. 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. Per the resource review and our site visit. there fs a potential erosion problem on the upper portions of the area of the site adjacent to I-405 since that area is so steep. However, there is no sign of erosion occurring during our site visit but the Sensitive Areas Folios indicate this as a potential erosion problem area. 3.3 Severe Flooding P�oblems(Type 3) Severe flooding problems. i.e.. a severe building flooding problem or severe roadway flooding problem can be caused by conveyance system overflows or the elevated water surfaces of ponds, lakes, wetlands or closed depressions. Severe flooding problems warrant additional attention because they pose a significant threat efther to health and safety or to public or private property There are no known flooding problems associated w�th this pro�ect site to the best of our knowledge The downstream drainage course appears adequate for the flow that was draining to it on the day of our site visit, which was September 23, 2014 at approximately 11:00 a.m. The sky was overcast and it had rained earlier in the day The h�gh temperature on this day was approximately 64 degrees 15564,001 doC �� .a.T" TAS K 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS TASK 4 DRAINAGE SYSTEM DESCRIPTlON AND PROBLEM DESCRIPTIONS Runoff from the project site wi41 be routed after detention and treatment to an existing catch basin which was not found at the time of the site visit. Hawever, the City of Renton mapping website indicates that there is a catch basin adjacent to the railroad tracks in Lake Washington Boulevard North which drains '.n a southeasterly direction to a manhole prior to crossing Houser Way. All of the rest of the downstream drainage course appeared more than adequate to convey the minor runoff coming from this project site Also, water quality will be provided meeting the Enhanced Water Quality Menu with the use of a modular wetland system which has GULD approval from the Depa�tment of Ecolagy for Enhanced Water Quality �sss� oci d�c TAS K 5 MITIGATION OF EXISTING 4R POTENTIAL PROBLEMS, INCLUDING WATER QUALITY PROBLEMS TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS, INCLUDING WATER QUALITY PROBLEMS ' There are no problems associa#ed with this downstream drainage cou�se or upstream basin contributing to this project site. Since this project site is providing Enhanced Water Quality, runoff conditions from the project site should be improved over what currently exists on the project site. This modular wetland system meets the Enhanced Water Quality Menu with a General Use Level Designation from the Department of Ecology for Enhanced, Phosphorus, and Basic Water Quality. 15564.001 doc � I � � � � 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 4.0 FLOW CONTROL AND WATER GlUALITY FACILITY ANALYSIS AND DESIGN A. Existing Site Hydrology The total area of development cn th�s pro�e�t si:e �s apprax�ma;ely 1.i7 a�res o! the overall 2.89-acre t site. Of that 1.17 acres, 0.47 acre is considered existing impervious surface and the remainder is till forest, portions of which are steep (over 15 percert slopes) and other portions are in the range of 5 to 15 percent slopes totaling 0.95 acre ot forest. All soils types in the area to be developed are Aldenrvood and Kitsap type soils. Please see the Existing Condition Basin Map in Section 1.0 of this Technical Informatian Repo^. for the land cover associate; ��,-�th tne ar�a tc �� vel��red on th s prcje�t G�te. B. Developed Site Hydrology Under developed conditions the site was determ�nea to be 95 percent impe�v�ous sur"ace totaling 1.11 acres with 0.06 acre of landscaping for a grand total developed area on the project site of 1.17 acres. Please see the Developed Condition Basin Map in Section 1.�� of this Technicai Information Report. A Flow Control BMP is used in the form of porous concrete. Please see the Level 1 Grading and Drainage Plan for t�e lacat:on� a�d tr:� 'Flow Control and Water�uality Sizing Criteria"for the calculations. 0.80 upstream acre drains into the walls on the east and south sides of the s�te. Conveyance ca4culations were performed to determine the capacity of the wall drains to convey this flow. Please see the Conveyance Basin Map and calculations in Section 5.� of this report. The remainder of the undeveloped site sheet flows away from t�e proposed developed area and is, therefore, apprapriately not included in any calculations. Tne wall drains will discharge to the downstream conveyance system in the right-of-way and bypass the an-site flow control and water quality systems. This is all in accordance ��ith the 2009 King County Surface Water Desiqn Mant�al as adopted and ar*�ended by tre City of Renton. C. Performance Standards The area-specific flow control facility �s the Peak Rate Runoff Flow Control Standard as �elineated by the City of Renton in their Amendments to the 2009 King County Surface UJater Design Manual. This is a peak rate runoff matching standard in which the 2-, i G-. and 100-year pre-developed peak runoff rates utilizing existing conditions are the release rates durir.g the same 2-. 10-. and 100-year respectively storm events 'or the developec condrtiOn. The appl�cab�e corvevance syster� capacity st�ndard �s the Mod�f�ed Raticral "�,�ethod as delineated in the 2009 King County Surface Water Design Manual uti{izing a 100-year p�ecipitation, a Manning's 'n' value of 4.014 in the pipes and an initial time �f concentration of 6.3 minutes. This is a very conservative methodology and usual�y creates pipes larger in size than what would normally be required for a given storm evert. The applicable land use-specific water quality requirement as determined per Section 12.8.1 of the City of Renton Amendments is the Enhanced Basic Water Quality Standard which is being met with the modular wetland system located downstream of de�entior for this proiect. Please see the calculations on the following pages of th�s report. 15554 0:"?8 doc r, ` '� . 1 In addition, oil controi is not required and the Source Control BMPs for this project site include educating the owner about the proper use of pesticides and fertilizers, as well as regular sweeping of the parking lot. D. Flow Gontrol System Please see the Grad+ng Plan on the followfng pages of this report which shows the flow control facilities proposed for this development. In addition, calculations to size the conveyance system are included in Section 5.0 af this report. E. Water Quality System Please see the Grading Plan on the following pages af this report that shaws the water quality faci(ity for this project, which is a Madular WeUand System (MWSj meeting the General Use Level Designation (GULD) of the Department of Ecalogy for Enhanced Basic Water Quality. The calculations to size this facility are also included on the following pages of this report. The GULD document dated Oecember 2015 is also included herewith. At the end of the document, it mentions that D�E accepts the use of an MWS even without pfants. Respanse to Camments firom the City af Renton Conceming Renton Amendments to 2009 King County Surface Water Design Manual Sections 1.2.3.2 E., F., and G. E. MITIGATION OF TARGET SURFACES THAT BYPASS FACILITY On some sites, topography may make it difficult or costly to collect all target surface runoff for discharge to the onsite flow control facility. Therefore, some project runoff subject to flow control may bypass required onsite flow control facilities provided that all of the iollowing conditions are met and must be approved by the City's Surface Water Utility: 1. The point of canvergence for runoff discharged fram ihe bypassed target surfaces and , from the projecYs flow control facility must be within a quarter-mile downstream23 of the , facilit�s project site discharge point, AND , Response: All bypass target surfaces are not really target surfaces because there rs no new impervious autside of the 1.17-acre site. The upstream area on site wil! not be , modified with this praject; therefore, there is no contributing area that was cansidered a ', target suriace and anyway fhe site bypass area converges with the runoff from the ' project sife within one-quaRer mite downstream. I 2. The increase in the existing site conditions 100-year�eak discharge from the area of �I bypassed target surfaces must not exceed 0.4 cfs, AND I, Response: The increase in the existing sRe conditian's 100-year peak discharge from I the area of bypassed target surfaces will not exceed 0.4 cfs. In fact ii will not incfease at i� att since there+s no modifcation proposed to thaf bypass area. I 3. Runoff from #he bypassed target surfaces must not create a significant adverse impact to downstream drainage systems. salmonid habitat, or properties as determ:ned by RDSD, AND Response: There wi�;be n� change to fhe c'ownstr�am drair�age systEm runoN from fhe bypassed area on site that wauld impact salmonid ha6itai or properties that need fo be protecfed as determined by RDSD. 15564.008.doc rj�� - 4. Water quality �equirements applicable to the bypassed target surfaces must be met, AND Response: There are no paliution-generating impervious surfaces 6eing created with this project in the bypass areas: therefore, this requirement does not apply. 5_ Compensatory mitigation by a flow control facility must be provided so tha e net effect at the point of convergence downstream is the same with ar without bypass. This mitigation may be waived if the existing site conditfons 100-year discharge from the area of bypassed target surfaces is increased by no more tha 0.1 s and flow control BMPs as detailed in Appendix C are applied to all impervious s s within t"e area of bypassed target surfaces. One or combination of the following methods may be used to provide compensatory mitigation by a flow control facility subject tc permission/approvals from other parties as deemed necessary by RDSD: a) Design the projecYs flow control facility or retrofit an existing offsite flow control facility as needed to achieve the desired effect at the point of convergence, OR b) Design the projecYs flow control faaliry or provide/retrofit an offsite flow control faci�ity to mitigate an existing developed area (either onsite or offsite) that has runoff characteristics (i.e., peak flow and volume)equivalent to those of the bypassed target surfaces but is currently not mitigated or required to be mitigated to the same flow control performance requirement as the bypassed target surfaces. Consideration of an offsite area to be mitigated for must take into account the likelihood of that area redeveloping in the future. Those areas determined by the City to have a high likelihood of future redevelopment that will provide its own mitigation may not be used as compensatory mitigation. Response: There will be no change to the runotf peak flow rates from the bypassed area from fhe existing condition to the proposed condition; therefore, no compensatory mitigation has fo be provided by the ffow control facility on srfe. Therefore. item No. 5 does not apply to this project site. F. BYPASS OF RUNOFF FROM NON-TARGET SURFACES The performance of flow control facilities can be compromised if the contributing area, beyond that which must be mitigated by the faciliry, is too large. Therefore, IF the existing 100-year peak flow rate from any onsite, upstream area {not targeted for mitigation) is greater than 50% of the 1�-year developed peak flow rate (undetained) for the area that must be mitigated, THEN the runoff from the upstream area must bypass the facility. Offsite areas that naturally drain onto the project site must be intercepted at the natural drainage course within the project site and conveyed in a separate conveyance system and must bypass onsite stormwater facilities. The bypass of upstream runoff must be designed so that all of the following conditions are met: Response: Per this paragraph, oK-site areas that naturafly drain onto the project site must be intercepted at the natural drainage course within the project site and conveyed rn a separate conveyance system and musf bypass on-sife stormwafer facilities. This is whaf this project is proposing to do through fhe use of a French drain type wal! drain and with 8-inch pipe dischargrng to the righf-of-way of Lake Washington Boulevard Norfh from ihe area contributing runoff to the sife under existing condition. 1. Any existing contribution of flows to an onsite wetland must be maintained, AND 'S564AOS doc�� Response: There is no existing contribution of ftow fo an on-site wet/and fo be maintained. 2. Upstream flows that are naturally attenuated by natural detention on the proJect slte under predeveloped conditions must remain attenuated, either by natural means or by providing add�ional onsite detention so that peak flows do not increase, AND Response: There is no naturally attenuated area by naturaf detention on the project s�te under pre-developed conditions fhai must rema�n attenuated. 3. Upstream flows that are dispersed or unconcentrated on the project site under predeveloped conditions must be discharged in a safe manner as described in Core Requirement#1 under"Oischarge Requirements" (p. 1-19). Response: There are upstream flows that could be consrdered dispersed or un-concentrated on the project site under pre-developed conditions but ihese are being discharged in a safe manner as described in Core Requiremenf /Vo. 1 under discharge requirements. 4. Bypasses shall be designed in accordance with standards of Core Requirement #4. Conveyance System Response: The bypass system was desrgned in accordance with fhe standards of Core Requirement No. 4 Conveyance System such that the wall drain was sized per the Modi�ed Rational Method. G. MITIGATION TRADES A projecYs flow control facility may be designed to mitigate an existing developed non-target surface area (either onsite or offsite) in trade for not mitigating part or all of the projecYs target surface area, provided that all of the following conditions are met: Response: This projecf is noi proposing to mifigate an existing developed non-target surface area either on site or�ff site. Therefore, the PaR G does not appJy. 1. The existing developed non-target surface area (i.e., an area of existing impervious surface and/or non-native pervious surface) must have runoff discharge characteristics (i.e., peak flow and volume) equivalent to those of the target surface area for which mitigation is being traded and must nat be cunently mitigated to the same flow control performance requirement as the target surface area. AND Response: There is no existing deveJoped non-target surface area being mrtrgated for. 2. Runoff from both the target surface area being traded and the flow control facility must converge p�ior to discharge of the runoff from the target surface area being traded onto private property without an easement or through any area subject to erosion, AND Response: There rs ro target surface a�ea be;ng t-aded: ,herefore. this requ;remert does nof apply. 3. The net effect in terms of flow contro� at the po�nt ef com�ergence do��vnstream must be the same with or without the mitigat�on t�ade AND Response: This is not applicable �.�F� _,�e -!�- ��., �.', 4. The undetained runoff from the target surface area being traded must not create a signi#icant adverse impact to downstream drainage systems, salmonid habitat, or properties prior to convergence with runoff from the fiow control facility. Response: This is nof applicabte. 5. Gonsideration of an offsite area to be mitigated for must take into account the likelihood of that area redeveloping in the future. Those areas determined by the City ta have a high likelihaod of future redevelopment that will provide its awn mitigation may not be used as a mitigation trade. Response: This is not applicable. 6. Mitigation trade proposals must be reviewed and approved wiih input from the City's Surface Water Utility. Response: This is not applicable. ��55=3�'�f�P d:ar ��./ FLOW CONTROL AND WATER QUALITY SIZING CRITERIA �w FLOW CONTROL AND WATER DUALITY SIZING CRITERIA Pre-Developed: Existing Impervious = 0.47 Acre Till Forest = 0.70 Acre TOTAL = 1.17 Acres Developed: 95°/a Impervious = 1.11 Acre Till Grass = 0.06 Acre TOTAL = 1.17 Acres Water Quality Menu used = Enhanced Basic A Modular Wetland System with G.U.L.D. from D.O.E. for Enhanced Water Quality was chosen. SIZE THE FLOW CONTROL BMP Use 104%of the site or 20%of the target impervious surface, whichever is less. � 10%of the site is the least. (1.17 Acres){0.10} =0.117 Acre= 5,096 SF For the Flow Control BMP, use porous concrete cn se�ected impervious sidetivalk areas. See plan. Total porous concrete = 5.115 SF 15564 008 doc J � r Z Q J 0. C� Z 0 � C� � � `- _ ;_ � ,oT A�E.� GRADING AND STORM DRAINAGE PLAN - LEVEL 1 ; � � = � S.�oR�pN � `�N �, � r�o• � �� - v ^ � �$. +5 3�T 6C � � , MEr'S'.�'COMC. �J P�p�OR MMC � � � . 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Z - ---- - - ---- 0?l22/2016 _�'< _.0 5+_ui�__ """°'s s�• C�J a �6 mi��/: KCRTS PEAK RATE FL�W CONTROL CALCULATIONS �.� i_� ��i .. ; �,:w frcquency•KCRTS ____ _ Return Penod 2 5 10 20 50 100 10" t'�.`�fi4rc1uul�>ks in Sea-�T'�c: • 15564pre.pks R —__..._ . � - N ♦ ♦ ♦ n � � L , ♦ � ♦ � ,.� ,0-1 � C U N � 1�) < _._.T_�__._ ___r _ � _ �_ _.T � T _ � t .- r _ _T _ _._ _.—r_---- 1 2 5 t 0 2CJ 30 40 50 f U 70 80 90 95 98 9 Cumulotive Probabddy � I :�CKT'v �cmmand CREATE a new Time Series ------------------------ Production cf Runoff Time Series Project Location : Sea-Tac Computing Series : 15564pre.�s� Regional Scale Factor : 1 . 00 Data Type : Reduced Creating Hourly Time Series File Loading Time Series File:C: \KC_SWUN;\KC_DATA`;ST!FUOR. rnf . Till Forest 0.70 acres Loading Time SeY�es Fi:a � ^: `.KC SWDM�.KC _�HTA`•STEIc��R. r::f . Impervious 0.47 acres Total Area : 1.17 acres Peak Discharge: 0.272 CFS at 6:0� o�� .'an : ir: Y�ar 8 ~ Storing Tim�= �er-:�s F��,� : i55E:pre. t�= . Time Series Computed KCRTS Command Erter the A.nalysi s TOCT•� �°�,c��_� --._a� -_� -�ci� ��. .�~a:--.d Compute PEAKS and Flow Frequencies ---------------—---------------- - Loading StageJDischarge _._�-�:�� : -_��.�=,�:;�:r� . -�r Flow Frequency Analys�s Time Series File:15564�re . ��t Project Location:Sea-Ta� r� _ya=rc: __ ` ___ .._ � . . _ . _ . _ . - . _- ==Fr r�'_:= Analysis Tools Commar.: RETURN to Previous N,e:.:: KCRTS Command CREATE a new Time Series -------- --- - --- - -- - - - -- - Product�c_, �f Runoff T:��e S�rae� Project Location : Sea-Tac Computing Series : 15564de•:-. t�f Regional Scale Factor : 1.00 Data Type : Reduced Creating Hourly Time Series File Loading Time :E: ��S _ _� . _ __ �r,�L.''� F.� �'-+:r 7i : s�__.. II'i� T'��1 v'_"3�� . �^ 3::_�� Loading Time �e� -.�c F _ .- t'�� .�.?•t' --.. �TF=;�_�, . _ .._ Impervious 1.11 acres Total Area : 1. 17 acre� Peak Discharge: 0.537 CFS at 6:0: -... _ ��. � �__ _ :_ - St�ri:ig ��.�N`c�_cs _ilc : -�� :.-�d;��. . tsi Time Series Compu��d KCRTS Comma:,d Enter the Analysis TOOLS '�ods�e Analysis Tools Command Compute PEAKS and Flow Frequenc;es ----- --------—------------- ----- - Loading Stage/Discharge ".�-�.�e : +55EYue�:�. �sf Flow Frequency Analysis Time Series File:15564dev.tsf Project Location:Sea-Tac Frequeneies & Peaks saired to r��e : �555=�dev.pn� Analysis Tools Commar.:: RETURN to Previous Me__.: ------------------ - - - KCRTS Command Size a Retention/Detention FACILIT'r -------- -------------------- -—-- - - Loading Retention/Detention Faci 1�_-•. �`. . _ . _=-. . -.. = -_ _i,= Retention/Detention Faci>;��. _._.= -: Edit Facili-�. Loadir�, -_ � - =__ - -.= i=_ :- i-_., ._ . . " __ Time Series rouna ln I�Yemory: 1�564c�v.tsf Saving Retention/Detention Facility File:15564convey.rdf Starting Documentation File:C:\KC_SWDM\Output\15564convey.doc Time Series =��und i� ti".emory: �5554de,✓. tsf Edit Complete Retention/Detention Facility Desiar: ---------------------------------- - Route Time Series through Facility ---------------------------------- Time Series Found in '�`e��r�� 15��-�r�e-�. -s� Reservoir Routing [R/D Facil�tyl Inflow/Outflow Analysis -- - - - - - -- - - - - -- - -- - - - - - Storing Time Series File : 15�c4rdcut tsF Facility Routing Complete � Peaks Calculation. .R/D Facility ! Flow Frequency Analysis ' -----------------------------------------—-—-------- -- ' Time Series File:15564rdout.tsf Project Location:Sea-Tac Frequencies & Peaks saved to File:15564rdout .pks . Peaks Plotting Reading Flow Frequency: 15564rdaut .pks � Reading Flow Frequency:15564pre .pks : End Graphics Command DownStream Analysis Complete Retention/Detention Facility Design ----------------------------------- End Sizing Retention/Detention Facility KCRTS Command Size a Retention/Detention FACILITY ---------------------------------— Loading Retention/Detention Facility File:15564convey.rdf . Retention/Detention Facility Design ----------------------------------- Edit Facility Saving RetentionjDetention Facility File:15564convey.rdf . Starting Documentation File:C:\KC_SWDM\Output\15564convey.doc . Time Series Found in Memory: 15564dev.tsf . Edit Complete Retention/Detention Facility Design ----------------------------------- Route Time Series through Facility - - - - - -- - ------------------------- Time Series Found in Memory: 15564dev,tsf . , Keservoir Rcuting [R/D Facility] ' �nflowjOutflow Analysis ' - - -----—-------------- Storing Time Series File:15564rdout.tsf . Facility Routing Complete Feaks Calculation. .R/D Facility , Flow Frequency Analysis -------------------------—------------------------ ----- Time Series File:15564rdout.tsf Froject Location:Sea-Tac ' �_equencies & Peaks saved to File: 15564rdout pks . Peaks Plotting ��ading Flow Frequency: 15564rdout .pks . Reading _ �ow Fr��v�ncy. 15;•-4F'r'= F.:s . End :�ra�rics Command ��°,::.��ieam ::ra��ysis C�-rple_� i � ,.. i Retentionj�etention .=acility Desiu:. ---------------------------------- Route Time Series through FacilitY ---------------------------------- Time Series Found :n _� . � _ : ._ : - ., � Reservoir Routing [R/D Facilit•,�: Infiow/Outflow Analysis Storing Time Seri�_� -__ _ _r�_- -: ; . .- - Facility Routing Complete Peaks Calculation. R/D Facili�, Flow Frequency Analysis Time Series File: 15564rdout.t:;� Project Location:Sea-Tac Frequ. _. �_. > ��:.� _ . . -� �- - - - - - -__ _ . . a _� Peaks Piotting Reading Flow Frequency:15564rd - : Reading Flow Frequency:155E�,;. � �-�s End Graphics Command DownStream Analysis Complete Retention/Detention Facility Desigr� --------------------- ----- --- --- --- End 5izing Retention/Detenti��n racili�; KCRTS Command Enter the Analysis TOOLS t�1o�::�e Analysis Tools Commar.d -- ------------------ - - RETURN to Previous Me:�� KCRTS Command eXit KCRTS Progr�.- �1 Flow Frequency Analysis Time Series File:15554pre.tsf Project Lacation:Sea-Tac ---Annual Peak Flow Rates--- ----Fiow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob {CFS) (CFS) Period Q.142 5 2j09/O1 2 :00 0.272 1 100 . Od 0.990 0.112 8 1j05JQ2 16:00 0_171 2 25.OQ 0. 960 0. 164 3 2I27f03 7:00 0. 164 3 10.00 0. 900 0. 117 7 Sj26/04 2:Q0 0_153 4 5.00 0. 800 0, 139 6 10/28f04 16:00 0. 142 5 3 .Q0 0.667 0.153 4 1/18/06 16:00 0,139 6 2 ,00 0. 5Q0 0,17I 2 i0j26/06 0:00 0.117 7 1.3� 0.233 0 .272 1 1/09/OS 6 :00 0.112 8 I_1Q 0. 091 Computed Peaks 0 ,23� 50 .00 d.98Q � _ Flow Frequency Analysis Time Series File:15564dev.tsf Praject Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob lCFS) (CFS} Period 0.275 7 2/09/O1 2;00 0.537 1 100.00 0.990 Q.240 8 1/05/02 16:00 0 404 2 25.00 0,96Q 0.333 3 12/OS/02 18:00 0.333 3 IO.OQ 0.90Q ��- 0,277 6 8/26j04 2 =00 0.330 4 5,00 0.800 0.330 4 10/28j04 16:00 0 .293 5 3 .04 0.667 0.293 5 1j18j06 16:00 0.277 6 2 .00 0. 500 0.444 2 10/26Jfl6 O :�Q 0.275 7 1.30 0.231 0.537 1 1f09/08 6 :00 0 .240 8 1 ,10 0 .091 Computed Peaks 0 .493 50.00 0 . 980 I �I � �li I � � ,i I I'i r. ` Flow Frequency Analysi� Time Series File:15564rdout.t-= Project Location:Sea-Tac ---Annual Peak Flow Rates--- -- ---Flow Frequency Analysis-- - - Flow Rate Rank Time of Peak - - Peaks - - Rank Return �rob (CFS) (CFS) (ft) Period 0.149 4 2/D9/O1 19:00 r71 6 .00 1 100 .00 0.9°� 0 .075 8 1/05/02 18 :00 0 : 158 4 .69 2 25.00 0.96 0.107 5 2/27/03 10:00 0 153 4 .55 3 10 .00 0.9�"- 0.077 7 8/24/04 0:00 0 . 149 4 .46 4 5 .Q0 0.8�": 0.091 6 10/28/04 20:00 0 . 107 3 .53 5 3 .00 0.6E"% 0 . 153 3 1/18j06 21:00 0 . 091 2 .61 6 2 .00 O.SC;` 0 . 158 2 11/24/06 6:00 0 . 077 1 .83 7 1 .30 0.23). 0 . 271 1 1/09!OB 10 :00 0 . 075 1 .�5 8 1 . 10 G. 04 '_ _��c�°.�t�d ��:_ . �3-; - . �� :_ . GC . . �'= � RetentioniDetention Facility Type of Facility: Detention Vault Facility Length: 68 . 00 ft Facility Width: 20. 00 ft Facility Area: 1360. sq. ft Effective Storage Depth: 6.00 ft Stage � Elevation: 32.00 ft Storage Volume; 8164. cu. ft Riser Head: 6.00 ft Riser Diameter: 12 .00 inches Number of orifices: 2 Full Head Pipe Orifice # Height Diameter Discharge Diameter tft� tin) (CFS) (in) 1 Q.OQ 1.45 0.139 2 4 .00 1 .25 0. 06Q 4 .0 Top Notch Weir: Rectangular Length: 1 .25 in Weir Height: 5.50 ft Outflaw Rating Curve: None Stage Elevation Storage Discharge Percolation ift) (ft) (cu. ft) (ac-ft) (cfs� {cfs) 0. 00 32_00 0. O.OQO d.000 o .ao o. oa �Z.o2 a�. o.00l o.00� o .ao 0. 03 �a.o3 4i . o.00i o.aio o.ao 0. 05 32 .05 68 . 0_002 0.012 0.00 O.Q6 32.06 B� . 0.0�2 0.014 0 . 0� 0. 08 32 .08 109. 0.002 0.016 0. 00 0. 09 32.09 122 . 0 .003 0.017 4.00 0.11 32.11 150. 0 .003 0.018 0 .00 0,12 32.12 163 . 0 .004 0.020 O.OQ 0.24 32.24 326 . 0 .007 �.028 0.00 0.36 32.36 490 . 0.011 0.434 0. 00 0.47 32.47 539 . 0 .015 �.039 0. 00 �.59 32.59 8Q2 . 4 .018 0.044 Q,00 0.71 32.71 966 . 0 .022 0 .048 D.�O 0.$3 32.$3 1129. 0 .�26 O .Q52 0.00 0.94 32.94 1278 . 0.�29 � .055 0.00 1.Q6 33.06 1442 . 0 .033 0.058 0. 00 1.18 33 .18 1605 . 0 .037 O .Q62 0.00 1.30 33.30 1768 . 0. 041 O.ObS 0.00 1.41 33 .41 1918 . 0.044 0 .067 0.00 1.53 33 .53 2Q81. D.04$ 0 .0'70 0.00 1 .65 33 .65 2244 . 0.052 0 .073 0.00 ' 1.77 33.77 2407 . 0. 055 0 .075 t1.00 ' Z.89 33 .89 2570 . 4. 059 0 .078 0.00 ' 2 .00 34 .00 272d. d.062 0_080 0.00 �', 2 .12 34 .12 2883 . Q.066 Q .063 O .OQ � 2 .24 34 . 24 3�46 . 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OG 7.40 39.40 10064_ 0.231 4 .780 O.OG 7.50 39.50 10200. 0 .234 4 .940 O.OG 7.60 39.60 10336 . 0.237 5.090 0.00 7.70 39.70 10472 . 0 .240 5.240 O.OG 7.80 39. 80 10608. 0 .244 5.390 O. 00 7. 90 39.90 10744 . 0.247 5.530 O.00 - 8. 00 40.00 10880. 0.250 5.670 _ �_ Hyd Inflow Outflaw Peak Storag� Target Calc Stage Elev (Cu-Ft) yc .'� ;� 1 0 . 54 0.27 0.27 6.00 38 .00 8157 . a . ! �"` 2 0.29 ******* 0.16 4 .69 36 .69 6380. 0. 14h 3 0 .29 0 . 16 0.15 4 .55 36 .55 6185. 0 .14� 4 0.27 ******* 0.15 4 .46 36 .46 6062 . 0 .13� 5 0.33 ******* 0.11 3 .54 35 .54 4815_ 0.11_ 6 0.33 0. 14 0.09 2.62 34 .62 3563 . 0.08� 7 0 .28 ******* 0.08 1.83 33 . 83 2494 . 0 .05" 8 0 .24 ******* 0.07 1.74 33 .74 2371 . O .O�Y ---------------------------------- Route Time Series through Facility.r Inflew '?'ime Series Fi'_P : 1�564d��.- . -_f Peaic Inf,low �ischarge: u . 737 CFS at 6 :00 on �an 9 in Yeaz - Peak Outflow Discharge: 0 .271 CFS at 10 :00 on Jan 9 in Yeaz Peak Reservoir Stage: 6.00 Ft Peak Reservoir Elev: 38.00 Ft Peak Reservoir Storage: 8157. Cu-Ft . 0. 187 Ac-F� Flow Frequency Analysis Time Series File:15564rdout . tsf Project Location:Sea-Tac ---Annual Peak Flow Rates-- - - - - - -F'c��.� F�equer.�y rnalys�s- -- - - - Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CF5? (ft) Period 0.149 4 2j09/O1 19:00 0.271 6 . 00 1 100.00 0.99� 0.075 8 1/OS/02 18 :00 0.158 4 .69 2 25. 00 0.9E; 0.107 5 2/27/03 10:00 0.153 4 .55 3 10. 00 0.9C� 0.077 7 8/24/04 0:00 0.149 4 .46 4 5. 00 0.8C� 0.091 6 10/28/04 20:00 0. 107 3 .53 5 3 . 00 O.EE� 0 .153 3 1/18/06 21:00 0.091 2 .61 6 2 . 00 0.5C^ 0.158 2 11/24J06 6:00 0.077 1.83 7 1. 30 0.2?": o.2�i 1 1/09/08 lo:oo o.o�s i.�s 8 i. lo o.o�- Computed Peaks ^ . �� s ?� 5C �� . �= _ -------------------------------_ Route Time Series through Facilit:.� Outflow Time Series File:15564rdout Inflow/Outflow Analysis Peak Inflow Discharge: 0 .537 CFS at 6 : 00 on Jan 9 in Year 8 Peak Outflow Discharge: 0 .271 CFS at 10:00 on Jan 9 in Year 8 Peak Reservoir Stage: 6.00 Ft Peak Reservoir Elev: 38.00 Ft Peak Reservoir Storage: 8157. Cu-Ft . 0.187 Ac-Ft Flow Frequency Analysis Time Series File:15564rdout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0.149 4 2/09f01 19:00 0 .271 6.00 1 100. 00 0. 990 0.075 8 1/05/02 18:00 0.158 4 .69 2 25.00 0. 960 0.107 5 2/27/03 10:00 0.153 4 .55 3 10.00 0. 900 0.077 7 8/24/04 0:00 0.149 4 .46 4 5 .00 0. 800 0. 091 6 10/28/04 20:00 0.107 3 .53 5 3 .00 4.667 0.153 3 1/18/06 21:d0 0.091 2 .61 6 2 .00 0. 500 0.158 2 11/24/06 6:00 0.077 1. 83 7 1 .30 0.231 0 .271 1 1f09j08 10:00 0.075 1.75 $ 1.10 0. 091 Computed Peaks 0.234 5.83 50. 00 0.980 � , i ' � i WATER QUALITY CALCULATIONS i �, � ; SITE SPECIFIC DATA � �� L �rcN PR0,IECT NAAIf 2335 - MARlOTT RES/DENCE CNN �N � �E �� N�� _ _ _ _ ! pROJECT LOCATION RENTON, WA ; j SrRUCTURE /D - - _ _ _ _ ,. _ , ,,,, TREATAIENT REOUIRED �;; IiOLUME BASE� (CF) 2-YEAR DISCHARGE RATE (CFS) w�y�� h �K �� " — �� JJJ 1 0.091 SEE NOTES JJJ TO PREVENT � PRE-fILTFR �- SCOURING R � TR£ATM£NT HGY AI/AlL48LE (fT) ,� • � CARIRI�E � `� PEAK BYPASS REDUlRED (CFS) - iF APPLICABLE 0.27 - -- ---� v ,rm �rm�,ti, , PlPE DATA l.E. MATER/AL D/AMETER ,��; ryr;�� , � � I '�; �;;�'�;; INLET PlPE 1 31.73 PI/C 12" ' „ ,,,, rNLET P/PE 2 �,,, I 1__ ,,, _ � 71 1 OURET P/PE 3123 Pl/C ; 12" . . — a ^ PRETREATMENT B/OFILTRA170N DISCHARGE �� ` - - --i _, a - - - tINDERORA/N } RIM ELEYAT/ON �o.oo �o.o0 40.oo '�"�FOLD LEFT END VIEI x/ SURFACE LOAD P,4RKWAY PARKWAY PARKWAY WERANaNEDl4 PA�N� BIOFILTIPATION,�RETREATMENT �RAME & COtiER �30" 2.5X4' i 024" � PLAN VlElx/ PERIME7FR W'ETLANOMEDlA i/OLUME (CY) 4.79 �� '�� WETLANDMEDIA DELNERY METHOD PER CONTR4CT ��( � �T� C/L �N� ORlf7CE SIZE (DIA. JNCNES) TBD = �dc�T�S: - - � - i I � INSTALLATION NOTES I o � i �. CONTR,4CrOR TQ PROUIDE ALI 1ABOR, EQU/PMfNT, M,4TER/ALS AND . � �`' . ;NCIDENTALS REQUIRED TO OFFLOAD AND lNSTAr'.L THE SYSTEM AND — =34.3J AAPURTENANCES lN ACCOROANCE WlTH lH/S DR,4WlNG AA1D THE `w = MANUFACTURERS SPEC/F1CATtONS, UNLESS OTHERW/SE STATE� IN o, = MANUfACTURERS CONTR,4CT. � ' � . � Z. u�N1T MUST Bf lNSrALLED ON LE�EL BASE. MANUFACrURER 1 , .� RECOMMENOS A M!N/MUM 6" LEVEL ROCK BASE UNLESS SPECIFIED BY � � � - ° ' ' _ j2• pVC -� � ` __ TNE PROJECT EN�iNEER. CONTR4CTOR !S RES,�ONS/BLE TO �ERlfY ` ��" ---" - - - - - - PROJECT EN6/NEERS RECOMMENDED BASE SPEelF1CATlONS. 12� � °0 ------- ----- ----- _ 6'�N1N� BASE , . ._ I .�. ALL P/PES MUSr BE FLUSH WITH fNS/DE SURFACE OF CONCRETE. � � - (PlPES C.ANNDT lNTRUDE BfYOND FLUSH). INVERT OF OUTFZOW PIPE 6� 8'-0� 6' ' 8'-0' - 6' MUST BE �LUSH w�rH DrSCt�RGE CMaMBER Ft00R. ,4LL G,4PS 9=�� 9'-0' �ROUND P/PE5 St�4LL BE SFALED WATER TI6NT WITH A NON-SHR/NK ELEI/ATION VIEI�/ RIGHTEND V/EU'/ GROUT PER MANUFACTURERS STANDARD CONNECT70N DETAIL AND SMALL INTERNAL BYPASS DISCLOSURE: MEET OR EXCEED REG/ONAL P/PE CONNECnON STANDARDS. D/SCHAltGE/B�OFUTRAT/ON 4. CONTRACTOR TO SUPPL Y AND /NSTALL ALL EXTERNAL CONNEGTING TN£DES16N AND CAPAClJY OF TNE PEAK CONVEYANCE Mt?H00 r0 BE RfVI£WED P/PfS. AND �IPPROVFD 8Y JN£E/YG/NEER Of'R£CDRD. HCL(S)AT PfAK F1(JW SNALL 9E 5 r�NTRACTOR RESPONS/BLE FOR lNSTALIAT/ON OF ALL R/SERS, �ssED ro OvsuRE ,vo uPsr� �tov0�nrc. � Ha �wo erPass Z YEARS DISCHARGE RA1F (CFS) � u.09; MANHOLES, AIVD NATCHES CONTRACTOR TO GROUT ALL MANHOLES AND �''�m" SNowiv �v Q�tw�nrc ,�E us� FOR curaaNcE o,vcr. LOW INFLOW PIPE DISCLOSURE: OPERATING HEAD (FT) 2.8 NATCHES TO MATCH FIN/SHED SURFACf UNLESS SPECIFlED OTHERW/SE. 6. DR;P OR SP.RAY /RR/GATlON REQUlRED ON ALL UNlTS W/TN VEGETATION. �,�,��p Ol��F�CuuUtAno�OF�EM�a PRETREATMfNT LOAD/NG RATE (GPM/SF) u.2 G E N E RA L N OTES � �'�� R. FA{LUR£ TO DO S� A49Y RfSULT/N BLOCKAGE WETLAND MEClA LOADING RATE GPM SF �.5 A7 tNfLOW POIM S WHACH AfAY CAUSE UPSTREAAI F10001NG. � � � ' MANUFACTURER TO PRO�IDE ALL AI�4TER/ALS UNLESS OrHERWtSE NOTED. n,��r ae.�wr aE PROPRIETARY ANtJ CONf1DENTlAL• M WS-L-O-S'V UG 2. ALL D/MENS/DNS, ELEYATIONS, SPEClFICATlONS AND CAPACITIES ARE SUBJECT TO ��D 8'"°i��''"�°i` �Faco�r�s P�� n�n�wnra�c�,vr,uvm�v rws az�+c rs n,�sorF ,�n o � u � a. R STORMWATER BIOFILTRATION SYSTEM �NA,NGE FOR PRUJECT SpEC,�FlC DR,4WlN6S DE7AiLlNG EXACT DIMENSIONS, i4'ElGHrS 7,{25,262' 7,470„16Z �6�+,��s, �n a��ro�ovuR wert,uw�s ss� �wr .aY� AccF�s�R�Es pc:�s� �r.h�TACT MANUFACTi,�R,EP,. �.3°Js'6= �u�° �c"' RE�OUCTlC�V�P'lR'OR'l5 A NfIOCF M�U7 7Hf NR�FN °`= _ _ STANDARD DETAIL �� ... �A'Ev/t :,F C?ff= PA�'S o+-'vJ',vG �Y�ScvJh .�F 4I��'�AR MT_?'.iWDS�r57fL5 5 �. »w waau�•v.�. .. _ : .� , . : "� eco � ocr December 2015 GE�ER.-�L l'SF: LE�'EL DESIG:�iATION FOR BASIC, ENHANCED, AND PHOSPHORUS TREATMEti'T For the �1«�S-L.incar 1lodular �'1�etland E:colog�''s Dc�cision: Based on Modular W-'etland Systems, Inc. application submissions, including the Technical �.valuation Report, dated April 1, 2014, Ecology hereby issues the following use level iiesignation: 1. General use le��el designation(GULD) for the MWS-Linear Modular Wetland Stormwater Treatment System for Basic treatrnent • Sized at a hydraulic loading rate of 1 gallon per minute (gpm) per square foot (sq ft) of wetland cell surface area. For moderate pollutant loading rates (low to medium density residential basins), size the Prefilters at 3.0 gpm/sq ft of cartridge surface area. For high loading rates (commercial and industrial basins), size the Prefilters at 2.1 gpm/sq ft of cartridge surface area. ?. General use level desi�nation (GULD) for the MWS-Linear Modular Wetland Stormwater Treatment System for Phosphorus treatment • Sized at a hydraulic loading rate of 1 gallon per minute (gpm) per square foot (sq ft) of wetland cell surface area. For moderate pollutant loading rates (low to medium density residential basins), size the Prefilters at 3.0 gpm/sq ft of cartridge surface area. For high loading rates (commercial and industrial basins), size the Prefilters at 2.1 gpmisq ft of cartridge surface area. s. General use level designation (GULD) for the MWS-Linear Modular Wetland Stormwater Treatment System for Enhanced treatment � • Sized at a hydraulic loading rate of 1 gallon per minute (gpm)per square foot (sq ft) of ' wetland cell surface area. For moderate pollutant loading rates (low to medium density '� residential basins), size the Prefilters at 3.0 gpm/sq ft of cartridge surfacc area. For high loading rates (commercial and industrial basins), size the Prefilters at 2.1 gpm/sq ft of cartridec surfacc area. - .� � 4. Ecology approves the MWS - Linear Modular Wetland Stormwater Treatment System units for Basic, Phosphorus, and Enhanced treatment at the hydraulic loading rate listed above. Designers shall calculate the water quality design flow rates using the following procedures: • V1%estern Washington: For treatment installed upstream of detention or retention, the water quality design flow rate is the peak I S-minute flow rate as calculated using the latest version of the Westem Washington Hydrology Model or other Ecology-approved continuous runoff model. • Eastern Washington: For treatrnent installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using one of the three methods described in Chapter 2.2.5 of the Stormwater Management Manual for Eastern Washington (SW�V1MEVl� or local manual. • Entire State: For treatment installed downstream of detention, the water quality design flow rate is the fu112-year release rate of the detention facility. 5. These use level designations have no expiration date but may be revoked or amended by Ecology, and are subject to the conditions specified below. Ecolo�•'s Conditions oi L:se: Applicants shall comply with the following conditions: l. Design, assemble, install, operate, and maintain the MWS — Linear Modular Wetland Stormwater Treatment System units, in accordance with Modular Wetland Systems, Inc. applicable manuals and documents and the Ecology Decision. 2. Each site plan must undergo Modular Wetland Systems, Inc. review and approval before site installation. This ensures that site grading and slope are appropriate for use of a MWS — Linear Modular Wetland Stormwater Treatment System unit. 3. MWS — Linear Modular Wetland Stormwater Treatment System media shall conform to the specifications submitted to, and approved by, Ecology. 4. The applicant tested the MWS — Linear Modular Wetland Stormwater Treatment System with an external bypass weir. This weir limited the depth of water flowing through the , media, and therefore the active treatment area, to below the root zone of the plants. This GULD applies to M�'VS — Linear Modular Wetland Stormwater Treatment Systems whether plants are included in the final product or not. 5. Maintenance: The required maintenance interval for stormwater treatment devices is often I dependent upon the degree of pollutant loading from a particular drainage basin. Therefore, Ecology does not endorse or recommend a"one size fits all"maintenance cycle for a particular model/size of manufactured filter treatment device. • Typically, Modular Wetland Systems, Inc. designs MWS - Linear Modular Wetland systems for a target prefilter media life of 6 to 12 months. • Indications of the need for maintenance include effluent flow decreasing to below the dcsign flow rate or decrease in treatment bclow required levels. • Owners/operators must inspect MWS - Linear Modular Wetland systems for a minimum of twelve months from the start of post-construction operativn to determine site-specific 1� maintenance sch4dule� and requirements. �'c�u must conduct inspections manthly durins the v��et season, and ever��other month during the dry seasan, (According to the � SWMM��tV1o', the wet season in western Washington is October 1 to April 30. Accordin� to SVb'MMEW, the tvet season in eastern Vdashington is t)ctober l to June 30). After thc first year ofoperation, ow�ners,'operat�rs ��3ust cundu�t in��«ti��ns ba,e� c�n the fin�in�s during the first year of inspectinns. • �onduct inspections by qualified personnel, follca�� r��<in�factur�r�� cuide(ines. ancl u�e methods capable af determining either a �ecrea�e in treat�d et�flu�nt I1o��rate an� or a decrease in pollutant removal ability. • 1�%hen inspections are perfortn�d, the follaw�ing findin��5 tv�ic-allti� ser�� a. n�r�int�n;�r�ce triggers: • Standing water remains in the vault between r��in e��nt�, t3r • BypasS occurs during storms smaller than the design 5torn�. • If excessive floatables(trash and debris) are present (but na standing water Qr excessi��e sedimentation}, perform a minor maintenance cansisting af gross solids remoL�al, not prefilter media replacement. • Additional data coIlectian will be used to create a correlatian between pretr�atment chamber sediment depth and pre-filter clog�;in�(see Issues ta he Addressed by titc� Compan��sectian belaw) 6. Discharges from the MVi'S - Linear Modular\h�etland Stormwater Treatment System unit� shall not cause c�r e�ntribute to �aater quality st�ndards �•i��lati�ns in receii�ing «�aters. Applicant: '.vlodular ��"et:and S��stems, Inc. Applicant's Address: PO. BoY 8h9 Oc�un.si�e. C.� 9?(75=1 Applic�tion Documents: • Or�ginal Applicau�n for Co�triitiranc�l Ltse Le��e1 D�slgnatiori, �Vlodular 4l�`etland S��tem. Linear Stormwater Filtration System Modular Wetland Systems, Ine., January 201 1 • Qualitv Assurance Project Plan: Modular Wetland sti�stem — I.inear Treatm�nt S�-sreln performance Monitoring Project, draft, January 2011. • Revised Application for Conditional Use Level Desi�l�uuc�n, ','�'Ic�dular t�`etland S��t�11�, Linear Stormwater Filtration System Modular Wetland Systems, Inc., May 2011 • Memorandum: Modular R'ettQnd System-Linear GG'LD Applicaiion Supplementur�i� U�rra, Apri12014 • Technical Evaluatton Report: Modutar- t�'etlnr�d S�°ste.m S1nr•m��•c�ter �'rearn�ent�i�ctE=�r� Performc�nce hfonitoring, ,9pril 2(I14. � �� Applicant's Use Level Request: General use level designation as a Basic, Enhanced, and Phosphorus treannent device in accordance with Ecology's Guidance for Evaluating Emerging Stormwater Treatment Technologies Technology Assessment Protocol — Ecology (TAPE) January 2011 Revision. Applicant's Performance Claims: • The MWS — Linear Modular wetland is capable of removing a minimum of 80-percent of TSS from stormwater with influent concentrations between 100 and 200 mg/1. • The MWS — Linear Modular wetland is capable of removing a minimum of 50-percent of Total Phosphorus from stormwater with influent concentrations between 0.1 and 0.5 mg/1. • The MV1W S — Linear Modular wetland is capable of removing a minimum of 30-percent of dissolved Copper from stormwater with influent concentrations between 0.005 and 0.020 mg/l. • The MWS — Linear Modular wetland is capable of removing a minimum of 60-percent of dissolved Zinc from stormwater with influent concentrations between 0.02 and 0.30 mg/1. Ecology Recommendallons: • Modular Wetland Systems, Inc. has shown Ecology, through laboratory and field- testing, that the MWS - Linear Modular V�'etland Stormwater Treatment System filter system is capable of attaining Ecology's Basic, Total phosphorus, and Enhanced treatment goals. I�indings of Fact: Laboratory Testing i'he MWS-L.inear Modular wetland has the: • Capability to remove 99 percent of total suspended solids (using Sil-Co-Sil 106) in a quarter-scale model with influent concentrations of 270 mg/L. • Capability to remove 91 percent of total suspended solids (using Sil-Co-Sil 106) in laboratory conditions with influent concentrations of 84.6 mg/L at a flow rate of 3.0 gpm per square foot of inedia. • Capability to remove 93 percent of dissolved Copper in a quarter-scale model with influent concentrations of 0.757 mg/L. • Capability to remove 79 percent of dissolved Copper in laboratory conditions with influent concentrations of 0.567 mg/I. at a flow rate of 3.0 gpm per square foot of media. • Capability to remove 80.5-percent of dissolved Zinc in a quarter-scale model with influent concentrations of 0.95 mgll, at a flow rate of 3.0 gpm per square foot of inedia. , • Capability to remove 78-percent of dissolved Zinc in laboratory conditions with influent concentrations of 0.75 mg/L at a flow rate of 3.0 gpm per square foot of inedia. , �g ' Field Testin� • 1Vlodular Wetland Systems, Inc. conducted monitaring vf�n MVVS-Linear(Model # MWS-L-4-13} from April 2012 through May 2013, at a transportation maintenance facility in Portland, Oregon. The manufacturer collected flow=-wei�hted compasite samples of the system's influent and effluent during 28 separate stortn events, The system treated approximately 75 percent of the runoff from 53.5 inches of rainfall during the manitaring period. The applicant sized the system at 1 gpm/sq ft. (wetland media) and 3gpmisq ft. {prefilter). • Influent TSS cancentrations for qualifying sampled storm events ranged from 20 to 339 mg/L. Average TSS removal far influent concentrations greater than 100 mgiL (n=7} averaged 85 percent. For influent cancentrations in the range of 20-100 m�/L (n=18), the upper 95 percent confidence interval about the mean effluent concentration was 12,8 mg,%L, • Total phosphorus removal for 17 events with influent TP cancentrations in the range of 0.1 to 0.5 m��'L averaged 65 percent. A bootstrap estimate of the lower 95 percent confidence limit (L�L9S) of the mean tatal phosphorus reduction was 58 percent. • The lower 95 percent contidence Iimit of the mean percent rernoval was 60.5 percent far dissolved zinc for influent concentrations in the range of 0.02 to Q.3 mg�L (n-11). The law•er 95 percent confidence limit of the mean percent removal was 32.5 percent for dissolved copper for influent concentrations in the range af 0.005 to 0.02 m�L (n=14} at flaw rates up to 28 gpm(design flow rate 41 gpm). Laboratory test data augrnented the data set, showing dissolved copper removal at the design flow rate of 41 gpm (93 percent reduction in influent dissolved copper of 0.757 mg;`L). Issues ta be addressed by the Compan�-: l. Modular Wetland Systems, Ine. should coilect maintenance and inspection data for the first year an all installations in the Northwest in order t4 assess standard maintenance requirements for various land uses in the region. Modular Wetland Systems, Inc. �h�uld use these data to establish require�i maintenance cycles. 2. Madular Wetland Systems, Ine. should collect pre-treatment chamber sediment depth data f�r the first year of aperation for all installations in the Northwest. Modular Wetland Systems, Inc. v��ill use these data to create a conelation between sediment depth and pre-filter ciog�ing. Technology Description: Dow�nIoad at http:l.'��vvw.mc�dulan�-etlan��.c��t�� Contact Informatian: ', Applicant: Greg Kent �'I Modular i�'ctland Svstems. tne. I P.O. Box 869 Oceanside, CA 92054 gkentrlhineteanenvir�„7rut,,r��1.n��t I'-, Applicant website: http:l:ww��.modufarwetlands.com-' Ecology web link: htt�:/Jwww.ecy.wa.govJprograms:`w<� :tc?rm��ater ne�}�tech index.html Ecology: Douglas C. Howie, P.E. Department of Ec�lo�y Water Quality Pro�,rram (360)407-6444 douglas.howie�ti ecv_u��.�u�� Revision History � Date � Re��sion � � 1 June 20] 1 Original use-level-designation document � September 2012 Revised dates for TER and expiration � January 2Q13 Modified Design Storm Description, added Revision Table, added maintenance discussian, modified format in accordance with Ecology ; standard } December 2013 Updated name of Applicant J ; April 2014 Approved GLLD designation for Basic, Phosphorus, and Enhanced treatrnent December?OI S Updated GULD to document the acceptance af MWS-Linear Modular V4'etland installations with or withaut the inclusion of plants. ' 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN _ �(� ' CONVEYANCE CAPACITY ANALYSIS FOR THE OFF-SITE ROAD IMPROVEMENTS Determine conveyance capacity in the proposed conveyance system in the right-of-way of Lake Washington Boulevard North. 100-year release from Hampton Inn detention vault= 0.062 cfs. 100-year flow from the upstream area on Hampton Inn = 0.07 cfs. Both of these flow rates were taken from the TIR for Legacy Renton (Hampton Inn) dated August 18, 2015, provided by the City of Renton. There is no upstream flow on Lake Washington Boulevard North from above (north of) Hampton Inn as dictated by topography and the fact that there is an existing manhole that collects that run-off and conveys it westerly under Lake Washington Boulevard North. Therefore, the only areas contributing to the proposed conveyance system are the Hampton Inn site and upstream contributing, the Mariott Hotel site and upstream contributing, and a portion of Lake Washington Boulevard North. The 100-year release from the Marriott site detention vault= 0.271 cfs, which has 1.17 acres contributing. There is 0.8 acre of upstream forested land bypassed around the Marriott detention vault and contributing to the proposed conveyance system, which per the conveyance calculations exhibits a peak flow rate of 0.29 cfs. There is 0.26 acre of road improvements (1/2 street contributing) from Lake Washington Boulevard North, which exhibits 0.25 cfs 100-year peak flow rate. Therefore, the total 100-year peak flow rate (assuming no attenuation, which is conservative) contributing to the proposed conveyance system with the flattest slope = 0.062 + 0.07 +0.271 + 0.29 = 0.943 cfs. The pipe with the flattest slope= 0.5%. See the capacity calculation on the following page. The pipes convey the flow with a worst case normal depth = 0.41 feet. 15564 008.doc 12" SD in Lk. Wa. Blvd. North Project Description Friction Method Manning Formula Solve For Normal Depth fnput Data Roughness Coefficient 0.012 Channel Slope 0.00500 ft!ft Diameter 1.00 ft Discharge �� ft'/s Results Normal Depth 0.41 ft Flow Area 0.30 ft' Wetted Perimeter 1.38 ft Hydraulic Radius 0.22 ft Top Width 0.98 ft Critical Depth 0.41 ft Percent Full 40.6 % Critical Slope 0.00493 ft/ft Velocity 3.15 ft/s Velocity Head 0.15 ft Spec�c Energy 0.56 ft Froude Number 1.01 Maximum Discharge 2.94 ft'!s Discharge Full 2.73 ft'/s Slope Full 0.00060 fU'ft Flow Type SuperCritical GVF input Data Downstream 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 % Normal Depth Over Rise 40.57 % Downstream Velocity Infinity ft!s r Bentley Systems,Inc. Haestad Methods SolB�atld'yeF�xMaster V8i(SELECTseries 1� [08.11.01.03] 6115/2016 10:21:22 AM 27 Siemons Company Drive Suite 200 W Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 2 � 12" SD in Lk. Wa. Blvd. North GVF Output Data Upstream Velocity Infinity ft/s Normal Depth 0.41 ft Critical Depth 0.41 ft Channel Slope 0.00500 ft/ft Critical Slope 0.00493 ft/ft • r Bentley Systems,Inc. Haestad Methods SoIBButl�Master V8i(SELECTseries 1) [06.11.01.03] 6/15/2016 10:21:22 AM 27 Siemons Company DNve Suite 200 W Watertown,CT 06795 USA +1•203-755-1666 Page 2 of 2 SIZE THE COALESCING PLATE OIL/WATER SEPARATOR � from 3;4-�nch hose fiow�ng 8 �ps = �A!�V'� _ (0.0031 sf)(8 fps) = O.Q245 �fs (0.0245 cfs) = 11 gpm A 25-CPS will treat 20 gpm and meet D.O.E s-ar�a-ds T�erefore. a 25-CPS s more i�Gn a�eq.;ate _-,_� _ �_ � 1 � I � � 1 � ! ' � . � �� li i 25-CPS OIL WATER SEPARATOR Projected Plate Area = 64 Sq/ft I �,� �� Maximum Process Flow - 60 GPM ' :� �. , � , E,� . � . , �, � r .-.-' ,- ? , �., '��/ �i�� `�� \\ �/ /�� 1`� � w� FV�� /�� FU�� 8�� OpEf1 � .' � � �� L� � i�� \ \ ��i� '� �� f,�� "� _i � I ��. �` L. - -i- t � �� ' ----�i-��,_ Recessed L�ft Hon die �� .` -_ !- I-_ ,,� �- i I e��` � -._��i � i �i�� i�i' --i � - -i-i-i-i-I-i-�-i- =� , ' Cover With - - - -+-i-i-;-�-i-i-�-�- - -� � Ad'ustable Frame _-_-_- -�-�-�-�-�-�-�-�-�-� , j �� -� i-i-i�j� � � i-i �-: i-� i- i No. 38/25-TA -' '-'i'i�i'i'-i_ .: - �i-� -i=i i '-- 220 Ibs. I -lII � I - ;-ill ' I � -�- .. -I-I 1 - -I i I-I-I ! 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Hole N (V , '\MNv'�/W\.� a , s Q I ��'\.��^.,^ ^.J��.1.� � � �� .I � y �• z ��"` � . � . ��--- ,- . - ,..-„ . . "'� --- 3 . I � � ---. � ---— • r � . � . � �-- 1'-2�" 2'-9�" ''-<i - � 1 SECTION AA STRUCTURAL NOTES: ti��rMA"Ja N�E�E� 1. Co�crete: 28 Day Comprossive Strenqth fc= 7000 psi Top Of Seporator E evat o� 2. Rebar: ASTIiI A-615 Grade 60 Inlet Pipe Size: 3. Mesh: ASTId A-185 Grade 65 Inlet Pipe Elewtion 4. Design: ACI-318-05 Buitding Code Outlet Pipe Size: ASTM C-890 'Minimum Structural Design Outlet Pipe Elewt�o� Looding For Underground Precost Concrete Water pnd Wastewoter Structures' BASIC DESIGN INFORMAT ON 5. Loods: HS-20 Truck Wheel w/ 307G Impact Per AASHTO INFLUENT CHARACTERiST1CS Oil Specific Gravity. 0.88 GENERAL NOTES: Opxatinq Temperoture: 50' 1. All Boffles ond Weiro To Be 3/16" SteN Plote ��fluent Oil Concentrotion: '�C pp� 2. Stotit Water Depth = 1'-4� Mean Oil Droplet Size: 130 Micrors 0.033 tt min ON Rise Rate 3. Controctor to: Design Per Washington State Depa-:Te��' :; $upply and instali All Plping dt Sampflng Teea t�X _" - Grout In All Pipes �OW EFF'�UENT COLLECTED filt �th Cleon Watar Prior To �Start–Up" Qf System RA� ��, �� Varify All Blockout Sizes and �ocationa 20 GPM 10 pDm 60 Micron SCALE: 3/4" = 1'-0" � � ,Zs., o2oos-zoiz oid�c��,i�� onauburn.com PIPE CONVEYANCE CALCULATIONS '�, � - - i� oxis f3Af�GHAUSf=N GONSUI TfNG FNf�WF..ERS PIF'F FLOW(;�L��L11 FllOR using Ihe Rational Methad&Manning("ormula KING COUNTY OESIGN FOR 100 YEAR STOF2A1 JOB NAME RENTON MARRIOTT NOTE:ENTER DEFAULTS AND STQRM pATA HEFORE BEE�INNING JOB#: 15564 UEFAULTS C= 0 9 n= 0 014 FILE N�: 15564-104.X1,S d= 12 Tc- 6 3 A=Contributing Area(Ac) Ud=Uesign Flaw(r,fs) COEFFICIENTS FOR THE RATIQNAL METHOD"Ir"-EQUATI�7N C=Runoff Coefficient Qf=Full Capacity Fiow Icfs) STORM Ar � B� Tc=Time of Concentration{min) Vd=Velociry at Design Fiow(fps) 2YR 1.58 0.58 1=Inlensity at Tc(in/hr) Vf=Velocity at Full Flow(fps) 10YR 2 44 0 64 PRF.CIP= 3.9 d=Diameter oi Pipe(in) s=Slnpe of pipe(°�,) 25YR 2.68 0.65 Ar- 2.61 I -_ �_angth of Plpe(ft) n=Manning Roughness Coefficient 50YR 2.75 0.65 Br 0,63 ._.... _ D=Walsr Depth at�d(in) Tt=Travel Time at Vd Cmin} 100YR 2.61 0 63 FROM TO A s L d Tc n C SUM A A'C SUM A"C I ��i r�f polQt f�ri�1 f� vt �'d 1 i ❑cc_== --��- -__-�.- --•�-••-� nn=aac =s=ma mascmx sasaam mmxmca scasx« --_.�..__ ______________ __.____ __ ______ r__c__ _____o m._=- ---__ __-__ C81 CB2 0.28 1.00 72 12 6.3 0.014 0 9 0.28 0 25 0.25 3.19 0.80 3.31 0.243 0.335 4.02 4 21 3 47 n 35 C82 VAULT 0.80 t.16 45 12 6.6 0 014 0,9 D_88 0 54 0J9 3 09 2.44 3.56 0.686 0.608 7.29 4.54 4 88 �i I5 C83 VAULT 0 29 2 25 4 12 6 3 OA14 p� 0.29 0.26 026 3.19 0.83 4.96 0.168 0.27d 3.29 6.32 4 68 �7 tl i WALL CB6 0.80 0 50 165 6 30 0 0 014 0 3 O A 0 24 0 24 1 19 0 29 d 37 0.778 0,662 3 97 1 88 2 08 1 33 ..�, �'ar�c� 1 (��'� , PIPE CONVEYANCE BASIN MAP � ,�- � _--- Q � � �oT A�.> GRADING AND STORM DRAINAGE PLAN — LEVEL 1 � N - ,,:.�.:= i � s-�oRCAN / � . ��;��Y�4�'V� � � � �— o .� � � � c , — �$. �.s�� _ ��r� tr'�� ! {��,..��,�,-� � � ONEIk 6' PK R00� DRMM O�MMSP'OVT _ � .. � : . . ca�e�r�wv� crn; (t i p ; , '� O RE�OGTE ExStir�G POwEa cO�E A utEi � 441�� ` ' `e� � � cONTt+ACtOR TO COOROwn1E vn*N �OC�� - 3 t ,� . 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GpY1ITY YD ECOr+ONC OEI�ONB�rt p� a ►i-�'`SA�R I�NTO/ MOTEL PERYT �15008�}S �GHqV� ^ �� P � �. GRADING AND STORM p m . � Z DRAINAGE PLAN LEVEL 1 z i�� To crtr ar�rvwos ' � ,• LM�[e: f ' • �i'� awa+�us[r cousun�c�+cr�as ; . , � CAL.L�YOU DI(� x« :.� � =nz�s rno��,c woTM ; 4 = °�"� - a,,� ..21,, -� _ ._. . 1-800-424-5555 �w,.,�9eou �1V pg a..» ,., _ O �oie � (aT5)25�-6222 E� __._____ __TT_____ w /` ' z (N , �:f �az<_;�5�-e*e� c�, ��^' �r;,� �a+�' Iscat .ao�oa� ..a -- oynrso+e -�.••:� �.,, e�.�.-._ ^'-^� _ ,�.C5 a 16 m �� 100 YEAR BACKWATER ANALYSIS �`1 �� --� .� .� -;- : ��5 � . � ..'7.�� , � �7-iCKTro'ATER COMPUTEP. PROGR.AM Ft}R PI�c.` e;�e da�a from file. 15564-1.�:�.: _._�r�rce ccndition at intermea�G�e i :1:-•-_:_--.= I'� _-___ .:�ter Elevation:38. feet I _ �_�charce Range:l.i4 to � . ��# �tv: �� _ . � __�-_ ��I . = - �'�flw Elevation:41.9 fee� ' :��r:NONE - -__ ..=- --: :s. �eet :t�'1.�°t�� f�,; � ��'-� �„- - _ _.� .,,.. _ . .� �.� - ��"CP @ 1.18� 4UT�Ei. 3`-�.�c I�:i:�T: 35.G� iA�^_Yt': 5 - ':� NC?. � . OVER��:�W-Ei,: 91.�0 BEND: 90 DEG DIAIW�L�TH: 9 .J ;�-R.�TI'.`'.: �. �� a �FS) HW (FT, �W �L�'V. * N-r�C DC �hd Tw DC� LE HWC; iiWI . . . �*****#�x��#**+*�*x*******#�***«*****x*****�x*******�*,+*�*�****#*:,+****�**# . y9 2.8" 38.15 * C}.a12 0. 51 0.41 3.25 3.25 2 .'79 2.87 C�.74 - �9 2.8� 38.1? * Q.pl2 0.53 0.42 3.25 3.25 2.75 2.8� G.78 - "4 2. 91 38.1° * 0.012 Q. 55 0.44 3.25 3.25 2.$� 2. 91 G.81 . ?4 2. 99 38.22 * 0.012 Q. 5? G,45 3.25 3.25 2.81 2. 99 G.89 _ .�4 2. 96 38.24 * 0.012 0. 58 G.4� 3.25 3.25 2.82 2.96 Q.87 . 94 2. 99 38.27 * O.Q12 0. 6� 0.4$ 3.25 3.25 2.E3 2. 99 G. 91 . �4 3. 02 38.3C� * 0.412 0. 61 0.50 3.25 3.25 2.85 3.0� O. G4 _ . 14 3. 05 38.33 * 0,012 0. 63 i.51 3.25 3.25 2.86 3.t?5 Q. 9% _ .24 3.08 38.36 * C.012 O.t�5 �.53 3.25 3.25 2.8� 3.08 1.02 . 34 3. i1 38.39 * �.012 0.66 0.54 3.25 3.25 2.8G 3. ii '. 09 - . �? ?. 'z 38.�2 * t�.012 D.b7 0.5� s.25 3.25 2. G0 3.�4 1.07 . : . _ . _ - = . �2 * 0.012 0. 67 0.55 3.25 3.25 2 . 90 3.14 1.07 ��, -f'�' � �.► - - .,�� - - r - - - - - -v+; * ;- - � i;h -J ,� .a�ti� ^s";, ,� _ _, �. _ _ :-t'. ._�._ _ . . _�__ � _ .. .� _ , . . . .. *,t i.��k a ±e xicx�k�rx�r**x**#,tir t�,t�t�r#x vr�-,rir,�-k-,�#i�ir+w x.x tir i�+*i:x x x-.r�x..�ir+,�i��r.=+x�>,r�t,e x» . 4? 2. 18 3$.18 * O.Q12 �,23 0.24 2.87 2.87 2.17 2.�8 0, 39 . 50 2.19 38.19 * �.012 0.30 �.25 2 .89 2.89 2.18 2.=9 0. 90 . �9 2 .22 38.22 * 0.012 Q. 31 Q.26 2 . 91 2. 91 2.2I 2.22 0. 4I . 57 2.29 ?8.24 * D.Q12 0.32 0.26 2 . °4 2.99 2.23 2.29 0. 43 . e�0 2.27 38.27 * 0.012 0. 33 0.27 2 .96 2.96 2.2b 2 .27 G. 44 . 69 2 .30 38.3C * Q.012 0. 39 Q.2$ 2 .�9 2.9� 2.29 2 .30 C7. 45 . 07 2 .33 38.33 * 0.C3i2 0. 35 G',29 3.02 3.�2 2. 32 2.33 0.47 . 7p 2.37 38.37 * 0.012 0.35 �.29 ?.05 3.05 �. 35 2.37 0. 48 .73 2 .90 38.40 * 0.012 0. 3� 0.30 3.08 3.J8 2. 38 2.40 J. 4° .7? 2.99 38.49 * 4,012 0.37 0,31 3. 11 3. 11 2. 42 2.44 0. 51 . 8� 2 . 98 38.48 * 4.012 0.38 0. 31 3.14 3. I4 2. 45 2.98 0.52 �14.� IL��=' yj� ��G-�k�'�'1',�' BACKWATER COMFUTER PROGRAM FOR PIPES �/��`� Pipe data from file:15564-2.bwp Surcharge condition at intermediate junctior.s .�!t��1 �i� Tailwater Elevation:38. feet Discharge Rarge:0.53 to 0.83 Step of 0. 1 �cfs) �-�-e�f'�cw Elevation:40.8 feet �?ei�:NONE _^.ar.::ei �,�,.�... � . feet � /�,,t,��'' j p �,� . ,�- - ��'� Pd;�. i : 4 LF - l�"Cr @ 2.25$ OUTLET: 3E•.71 INLET: 36.80 INTYP: 5 � 'CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO �E HWO HWI . . ..*********�******+*****,�***f****+***+**:*+**************.,.********�***+***** _ . 53 1.22 3� .02 * O.Oi2 0. 31 0.21 1.29 1.29 1.21 1.22 0. 40 . 63 1,22 38.02 * 0.�12 0. 39 0.23 1.25 1.29 1.20 1.22 0. 45 .?3 '_ .�2 38 .02 * �.012 0. 3E Q.29 1 .2° 1.29 1.20 1 .2� 0. 48 �I �� 6.4 SPECIAL REPORTS AND STUDIES . � 4�� „��\ �`�i � � O � W � i� J � � y t t i January 30, 2015 Earth Solutiuns NW �.�c: ES-3569.01 • t�t_t,�,� �. :��,r•-� _ ' .�.eil�[�'UC[iUtifVlC)i�ttfJ�ii��.�. ,. -�.. . -.. ..,.�. --�� .� �. �,. „_ . . ! W.I. Realty Acquisition Corp. �', 13647 Montfart Drive I Dallas, Texas 75240 ' Attention: Ms. Cary Fisl�er Subject: Groundwater Monitoring Summary Proposed Marriott Residence Inn Lake Washington Baulevard North ' Renton, Washington Reference: Earth Solutions NW. ��C Geatechnical Engineering Study ES-3569, dated November 20, 2014 Dear Ms. Fisher: In accordance with your request, Earth Salutions NW, LLC {ESNW} has prepared this groundwater monitoring summary letter for the proposed Marriott Residence Inn project. Two groundwater monitoring wells were instalEed at boring locations B-1 and B-2 as part of the subsurface exploration for the referenced geotechnical engineering study. ESNW has been visiting the site on a biweekly basis to monitor the groundwater levels at the monitoring wells on-site. Seasonal Groundwater �evels As requested, two groundwater moni'oring wells were instailed �o depths of 15 to 26 feet belaw existing grades to monitor the seasonal groundwater levels in the vicinity of the proposed hotel structure. The monitoring well locations are displayed on the attached Monitoring Well Location Plan (Plate 1). ESNW has been observing the graundwater levels at the manitoring wells on a biweekly basis to establish the local seasonal high groundwater levels. The following table d+splays #he groundwater fevels observed to date. • • - � _ `�� W.I. Realty Acquisition Corp. ES-3569.01 January 30, 201 S Page 2 Marriott Residence Inn Groundwate�Monitoring Data Location B-1 B-2 �' Surface 38 49 � Eievation ft, * , . __ _{_�__ _---- Date � Groundwater Depth 1 Elevation (ft.�� i Groundwater Depth/ Elevation {ft.1' 1 pi29f2014 � 8.33 29.67 19.25 29.75 11/1012014 I 8.33 3 29.67 19.25 29.75 11/25/2014 $.00 + 30.00 19.�0 30.00 12112/2014 7.83 30.17 18.50 30.50 12/2412014 7.54 30.50 18.17 3Q.83 116/2015 8.00 30.00 18.00 31.4� 1t19;2015 7.33 30.67 18.00 31.OQ 1t29f2015 7.42 30.58 18.00 31.00 'All depths and ei�vations are approximate, the weHs shouid be surveyed to determine exact elevations Note: Seasonai high levels are in bolt! Based on the groundwater conditions observed during our subsurface exploration, the groundwater levels abserved at the monitofing wells likely represent the local graundwater table elevation. However, the depths and elevations are estimated based on available survey plans; to determine exact groundwater elevations, the well locations should be surveyed. ESNW will continue to monitor groundwater levels on-site until the seasonal high groundwater level is determined, unless otherwise notified. We trust this groundwater monitoring summary letter meets your current needs. If you have any qusstions, or if additional information is required, please call. Sincerely, EARTH S4LUTIONS NW, LLC , �� ..--- � �. t � � Hen T. Wright, E.I.T, Raymond A. 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OQ �•�. x'�" �� ^ � °� t,' � '*" C�'+M � ,.._._._.�� a,� .� _ � � a W ,� � ;� ,� _ W� y O .+r111��' �^i�e f.. � IG — id � p ~ y; V � 'r C v � � � � ;? '� � ,..__ � � u � (, � PREPARED FOR W.I. REALTY ACQUISITION CORP. I, November 20, 2014 Updated April 21, 2015 _ H nry T. Wright, E.I.T. Staff Engineer � n A y 21 1,$� ; �r�pN Cp�� e. �� W AS//� y �I �� f �:�� 1 � , �� , r� , ;,:.�>>� � r ti ♦ / '�/.fl,,�� '�I1� 'T � • � Raymond A. Coglas, P.E. Principal UPDATED GEOTECHNICAL ENGINEERING STUDY MARRIOTT RESIDENCE INN PROPOSED HOTEL FACILITY RENTON, WASHINGTON ES-3569.01 Earth Solutions NW, LLC 1805 - 136th Place Northeast, Suite 201 Bellevue, Washington 98005 Phone: 425-449-4704 Fax: 425-449-4711 Toll Free: 866-336-8710 �� II � I � I ' II I . . . - � � � ' 6eotechnical Services Are Performed for • e�evation,conFiguration, location,orientation,or wefght of the � Spec�fic Purpos�s, Persons, and Projects ��d st��c��e, I �'iFO�E't,hfll� , ;��inF-"i$Si J i:.'�'Yr'if S�1"v'� ;�'t, .'IF»'t(h,�j�P(;fIC fi@�� Qf • ;,ompasition of the design iB�fTl,Of ' their cl�ent5.P,geofechn�cal engir�eering study condua�led tor a c�vil eng� • pr;,ject ownership. neer may not fuifili Lhe needs af a construction contrador or even anather ' civil engir� Because each geatechn�cal engineering study is uniq�,each As a general rule.atways iniorm your geotechnial engineer oi project geotechnical engineering report is unique.prepared sokelyfor the client.No changes—even minor ones---ar!d request an zssess�r�er�of their i�ripact. one exc�t you should reiy or your geotechnical engir�ering report without 6eotechnfca!engineers��nnof a�ept respons:brliry o�liabilrty for p�ob� f rst conferring with the geotechnical engineer who prepared it.And�;�one that a;cur u�cause their re�ur:s do;,nt consrder developments ol wnich —;�ot ever you --should app!y the report for 3ny purpose or pra;ef�t btiey we;e:��:t mr,:��;�C �,::eot?hesne�:ngin2il� ,,��±�;�;;3'�C Subsurface Condrtions Can Change �� C fUN R@� A geote�`ric��erg��n�g��,:�rt,�hasea � _rr��t; ns that existed at ��us prob�ems have arcur�eC bFca��e tho�e reiying on a geotechnical the time the stu�y was;,erf�rme��. D��not�e�y�r a gaotechnrca!enginPer- ' ?ng,:�rering repon��d no;read it all Do not rely on an executiv�sur�mary ing reportwhose adequacy may have been af�ected by:the passage of Do r�o`rP��se,ec;.,d�:�r��-�F;nt;;;•��v 'i�ne;by man-made events,s�h as constr�ction on ar adjacent to ttie 5ite; � or by nat�al events, such as flcods,earthquakes,or groundwater iludua- , A 6eoteehnical Eng��ing Repo�t Is Based on tions.Aiways contact the geetech�nical engir�eer before applying the report A �N1iq� 3et of Project-Specific Factors �o determine if it is still reliaole F minor ar�aunt ef additianal testing or 1�8�iPCh _'3!?(Iyi lt�'iS Cu ;i ��:� � ��'"b�� . r'�,fCl. �;lt'C'fl�fi3C- afl"dlySfS CC�UI(�pfrYu�t(i12f0�U�uC�I?fT1S iors when estabiish�r�}the scope of a study Typ�cai facto�s mclude:the c�iern's goa�s,objectives,and risk management preferences:me genera� Most 6eotechnical �ind'mgs Are Professio�l nature o{the structure irnoived, its size,and configurat:on:the location of OpIf110fIS the structure on the site;and other planned or existing site improver�ents, Siie::x�.r rat��n ��er�tit�es suDsurfa;,e�ond�(o�s on'y at those pu�nts�rhere such as access roads,parking lots,and underground utilities.Unless the subsurface tesls are conducted or samples are taKen.Geotechnical engi- geotechnical engineer who conduc�ed the study specifically ind+cates oth- neers review field and laboratory data and then apply their professianal e�wise.do not.►ely on a geotechnical engineering repoR that�_ judgment to render an o�inion about subs�:rface condi,ions tt�roughout the • not prepared for you, � site.Actuai subsurace conditions may ditfer—sanet�r�s signi�icantiy— • not prepaed for yo�r praject, from those indicated in your repa�t Retaining the geotechnical engincer • not prepared for rhe specific site explor�,or who developed your rep�rt to provide construction observation is the • compl�ed before+mport�t project changes were made. most effedive method of ma�aging the risks associated with unanticipaled � conditians. " Typical changes that can e�ode the reliability of an existing geote�hni�al eng�neering report irx;lude those t�at affecx: A R@(!01't'a Recommendations Me llbt Fnal • the function of the proposed strueture,as when iYs changed from a Do not overre!y on the con5fruct�cn •?ca�nmen�atiar��nc�uded in�o+�r 1 ! parking garage to an ot�ice building, or from a light industrial plant report. Those racommendatronsare not frnai,because geotechnical engi- • i�-�a�efr�gerated warehouse. r�eers develop them principally from judgmer�and opinian.Geotechnical er�gin�ers can finalize th�ir r�;ammendations only by observing ac�ual - - �� subsurface conditioru revealed during construction The geotechnrca/ have!ed to disappoi�tments,ciaims,a�d disputes.To help r�uce the risk � engineer who de►�loped your report cannot assume responsibi(ity or of such outcomes,geotechnicai engineers corrxranly inciude a variety of liabifity fw the r�oort's re�omrnendations if that engineer does nof perform expla�atory provisions in their reports Sometimes labeled'limitaiions" ��nstruction nbse.tiaf�vn. m2ny of these provisions indicate where g�techniql engir�eers'respons'r � :�Ges begin and end,tc help ot�e�s recognize their own responsibiiities ; ,+ 6eotechnical Engineering Report Is S�ect to a�d risks.Read tl�ese provisions dosely.Ask questions.Ya�r geotechnial N�Sit1iC1'pl'@�1011 ��g;�?e�s''u��esp�rd'�liy 2nd frankly. Ot��er de�ign;ea�-, T��ber �r,:sinterpretauon of geotechnical eng�neenng I reports has r�ulled�n�,;�stly probler�s Lower that risk by Faving your gec- Geoenvironmentai Concerns Are Not Covered f technical�gineer confe�with;pprcpriate members of the�esigr tearr af!er Tn??qui�r^ent,tech,niq�es,an�persornel .;sed to p2r(err�:a gc�:^v�;�,- submittira�the r�ort.Also retain your geotechnicai eng�neer to review peRi- :?rentai study d�ffer significantly from those used to perform a geotechnical nenf elements of�he design team's plans and specificati�s.Conir�ctors can study.For tt�t reason,a geot�chniql engineering report does not usually alse misinte�pret a geotechnical engir�ring report.Reduce that risk Cy relate any geoenv�ronmenta�findi�s,conclusions,or recommendations; having your geotechnica!engineer participate in prebid 2nd pr2ccnstr�ction e.g,about the I�kelinood of encountering underground storage tanks ar conieren�ps, and Cy�rcv�ding c�rstruct�o^.o�s�r��t an ra�u'ated cont2mir�ctits. lJr,an!icipated environmental problems hav�le�d ; ':-numerous project faiiures.Ii ye�h2ve not yet obtained your own geoen- iDo Not R�Iraw the Engineer'S LQgS � roncnenta� ir?ornation ask your geotechniql consu�tant tor risk man- � Geotechn�cal engireer�prepa•�` ��;��n��e;ting !ogs based u;,cr. a�e�nent gu�dan�e.Do n�t�ely en ar e,�+vi!on,�nental report prepared for their intar�re�atioa o`rie�d logs ar.;; ac�ora,u�y�eta.io prevent�rrors or ��c efse. omfssions,the logs included in a geotechniql engineering report should � never be redrawn fo�inclusion in architectura� or other desi �draw�n � Obtein Professional Assist�ee To De� with Mold � g. g.:. , On�y photographic or electranic reproduction is acceptable,b�f reCognize �?rs-��a:��es c�'� be?.�G�!e� ��,',� �.;ii�`ry�e;�g�.co�strucUon, ;' Lhat separatrng loos f.r�m fhe report can elevate rrsk ��perat�u�, an�ma�ntenance t�p�ever�;;;�-,�i ca�:anoures o`mold from ; growirg or mdoor surfaces.Te oe effeaive,all such strategi�s should be , 6�iV@ COt1U'BCtOPS 8 CORIp�tB R8p01't 8tq1 �,v�sed�ar the express purpose of mo!d prevention, integrated irto 2 cor�- � 6'�idBtlC@ �r?�ensive plar,and exe;,ut�wit�d�ligent oversight oy a proiessional ' Some owrer,and oes�g,proi�SS G�als mi�I2keliy Gel�ev?t�ey�c makc T�ol�prevention cons�ltant. Because;ust a sr.iall amount of water ot I co�trac��rs liable far ur�anticipated subs�rface conditions by lim�ting what rioisture can lead to the deve�ooment of severe riold infestations,a rwm- ; they provide for bid preparatipn.To he►�preverrt Costly probleTs.giw con- ber of mol�prevent on strafegies focus on keeping building surfaces dry. :tors the comptete geoiechnical engineering report,butpre#ace it with a While graundwater,w3ter infiltratioc�,and similar issues rnay have b�n arly written{etter of transmitta'.In that letler,advise contractc�s mat the addressed as paR�'the geotechn�cal engi�eering study whose find��gs ' repoR was not prepared f�r purpases of bid develop�nt ar,d that t�e are conveyed ir�this reoort,the geotechnical eng�ne�r�r�charge of th';s report's a�uracy is limited;encour�them to car�er w�th t��e geotechnicai ;,.o�e�t s.-ct�mold��?•�en!nn��nsu�tan�: none of the services per- engineer wFo prepared the report(a modest fee rr�y be requir�)an�or to lormed in connection with the geotechnica/engineer's study conduct add+tional��dy to obta+n the specific types of iniormation they were designed or conducted for!he purpose of mold preven- ' nced or prefec A p��id conference can also be valuable.Be sure contrar- tion. Proper implementation ol the recommendafions conveyed tors hav�sulficienf trme to perform additionat study.Only then might yc� irr this repoR will nat of itseH be suflicient to prevent mold lrom be in a position to give�antractors the best inform�ion available to you growing in or on the structure invalved. while requiring them to at least share s�rr�e�i�re n^an�lal •��p��v�s�b ��l�F� ster*�ming from unanticipated conditions ReIX, on Your ASF�-Member 6eotectnC� � Engmeer ior Addition� Assistance Read Respons�bility Provisions Cbsely ;�� ._-��:� �� M��- : �sc Fr��r r�� a�r�e�o�5��cechnicat Some clients, desig�p�oressionals. an��;;o�tra�:c-s oc ��t rrcogni�e'�at �ng�neers to a wide array of risk rnanagement techrnques tnat can be of geotechnical engincering is Ear iess exact than other eng�neering d�sc�- genuine benefit for everyone involved with a construction pro;ect. Confer plines.This ladc of understanding has created unre�alistic expe�tations that w+th you ASFE-member geotechnicai er�gineer for rare infornation. , ASFE i�� stt ��1• �� E�rt� is�11 Ccles;�dle R�ac,S��E i��5 S�!v=� -. ��- - � �elephore "sG1,`565-2733 racsiT,��e su.;�c;�-�u'. e-��I �nifl�asfe.org www.asie.or� CopyriyM 2004 by ASFE lrrc.DupNcation,ropra0uctlon,a copy�np o/fhis daumen�in r►hole or rn paR,by s�ry means whaiscevei,u s:r�cGy p�ohibi(ed,except wdh ASFE"s spec;tic wrirten permiu�ort Excerpnnp.puabny,or ottrerwise exnacmip wordinp trom tdrs aocument+s permrCsa ony wmi Me express wrlrren perm�ion o�aSf�aod onh k�r �urposes ol schdariy rBsearch or pook re✓iaw.On/y memGers ol ASFE may use Ma documant as a comptement to w as�n element of�Qeote�hnka/enqxberirq repo^ 4^: n•�~r• /rnrt�,indrvrdua/,a other entlry that so uses Mis document wiUrout bemy aa ASFf inemDer cou10 be commrftrnp rrepliyent or mfentiorral(trauOWentJ misreprese�•,.�r�- Ii6ERO6C4�QM r i � � i November 20, 2014 Updated April 21, 2015 ES-3569.01 Earth Solutions NW ��. W.I. Realty Acquisition Corp. • �,c;_�.��.-n:,.,�� F�E�;��,t., . 13647 Montfort Drive • t r�n.UuCtiun!�1oni:urr�, Dallas, Texas 75240 • �� Attention: Ms. Cary Fisher Dear Ms. Fisher: Earth Solutions NW, LLC (ESNW) is pleased to present this report titled "Updated Geotechnical Engineering Study, Marriott Residence Inn, Proposed Hotel Facility, Renton, Washington". This report has been updated to provide additional discussior and analysis of c�itical areas and groundwater. Based on the conditions encountered during the fieldwork, the site is underiain primarily by firm pre-Fraser silt and sand deposits with upper loose soil deposits throughout the western portions of the proposed structure iocation. We understand the site will be developed with a hotel facility and related infrastructure improvements including exterior parking lot areas. The proposed hotel structure will largely be constructed at-grade throughout the topographically lower west side af the site. Excavations of up to approximately six to eight feet are estimated to be �ecessary to compiete the outdoor parking lot structure construction. UJe antic+pate the �xcavations will be completed using temporary slope excavations. Based on the results of our study, the proposed deveiopment is feasible from a geotechnical standpoint. To mitigate post construction settlement of the proposed hotel facility structure, foundation support will need to be derived in the underiying dense to very dense silt and sand deposits. In our opinion, conventional foundations supported on aggregate piers advanced into the underlying silt and sand deposits can be considered where these deposits are not exposed at or near design footing elevations. Due to groundwater levels at-depth and the loose nature of the upper soil deposits, casing of open-hole the aggregate pier excavations should be anticipated. Recommendations for site excavations, foundation design, aggregate piers, and other pe�tinent geotechnical recommendations are provided in this study, as appropriate. We appreciate the opportunity to be of service to you on this project. If you have questions regarding the content of this geotechnica! engineering study, please call. _ � �� Sincer�ly, , > E RTH SOLUTI NS; , LtQ� � / l �� ' �� ayr}�on�A. Coglas, P'� �principal Table of Contents ES-3569.01 PAGE INTRODUCTION . .. . 1 I'I General ................ ........................................................... 1 �, Proiect Description ............. . ... . ...... . .. .... ...... .. .. . ... 2 '� SITE CONDITIONS ... ...... .. .. . ........ . . 2 Surface. . .. . .......... ... ... ............ .. _. ...... ..._. ...... . . . ........ 2 Slope Reconnaissance/Stability Assessment................ 3 Aerial Photograph Review............ ........................... 3 Subsurface..................................................................... 3 Topsoil.....................................................,......................... 3 Fill... ...... ............................................................... 4 I', NativeSoil.......................................................................... 4 GeologicSetting................................................................ 4 ' G ro u n dwate r........... ............ ............................................. 4 Seasonal Groundwater Monitoring...... ...... ................ 5 CRITICAL AREAS AND GEOLOGIC HAZARDOUS AREAS ASSESSMENT......................................................................................... 5 Site and Construction Plans....................................................... 6 Landslide Hazard............................................................ 6 SteepSlopes..................................................................... 6 Erosion Hazard................................................................. 7 Numerical Slope Stabilitv Analvsis.................................. 7 Analvsisof Proposat................................................................... 9 DISCUSSION AND RECOMMENDATIONS........................... .......... 9 General........... ........................................................... ..... 9 Site Preparation and Earthwork.......................................... 10 Excavations........................................................... 10 Structural Fill.......................................................... 10 Erosion Control....................................................... 11 Foundations......................................................................... 1 Aggregate Piers...................................................... 12 Slab-On-Grade Floors........................................................ 13 Retaininq Walls................................................................... 13 Excavations and SloRes... _. ............ ... ................. ... . .... ... 14 Ea^n Scl�t�^s N�� _LC ;r � ` , Table of Contents Continued ES-3569.01 I PAGE ' Seismic Considerations............................ ....................... ....... 14 Drainaqe...... ...... ....................... .... ................................... 15 Infiltration Evaluation............ .................................... 15 Utilitv Support and Trench Backfill................................... ... 15 LIMITATIONS... ...... ... ... ... ............................................................ 15 ' Additional Services............ ........................... ... ...... ............ 15 I GRAPHICS Plate 1 Vicinity Map Plate 2 Bo�ing and Test Pit Location Pian Plate 3 Cross Section A— A' Plate 4 Cross Section B — B' Plate 5 Retaining Wall Drainage Detail Plate 6 Footing Drain Detail APPENDICES Appendix Q Subsurface Exploration Boring and Test Pit �ogs Appendix B Laboratory Test Results Grain Si2e Distribution Appendix C Aerial Photographs Appendix D Slope•W Computer Output Earth Solut�ors N�^J LlC I ; �%' I, � � % I UPDATED GEDTECHNICAL ENGINEERING STUDY MARRIOTT RESIDENCE INN PROPOSED HOTEL FACILITY RENTON, WASHINGTON ES-3569.01 INTRODUCTION General This updated geotechnical engineering study was prepared for the proposed hotel facility to be developed along Lake Washington Boulevard North in Renton, Washington (see Vicinity Map — Plate 1). This geotechnical engineering study has been updated to address recent City of Renton review comments regarding groundwater conditions and project impacts on the steep slope areas. The overall purpose of this study was to explore subsurface conditions across the site and develop geotechnical recommendations for the proposed project. Our scope of services for completing this geotechnical engineering study included the following: • Subsurface exploration and characterization of soil and groundwater conditions by advancing borings and excavating test pits on the accessible areas of the site; • Laboratory testing of soil samples obtained during field exploration; � Site reconnaissance and aerial photo review: • Providing an assessment of sfope stability; • Groundwater level monitoring and data collection: • Conducting engineering analyses including temporary shoring and foundations, and; • Preparation of this updated report. The following documents/maps were reviewed as part of our report preparation� • ALTA/ACSM Land Title Survey, prepared by Barghausen Consulting Engineers. Inc., dated September 9, 2014; • Slope Over 40% Encroachment Exhibit, prepared by Barghausen Consuiting Engineers, Inc., dated September 9, 2014; • Architectural Plans, prepared by Jensen Fey, dated April 1. 2015; • Aerial Photographs (ca. 1951 to 1970); • Geologic Map of Washington, Northwest Quadrant, and: • Renton Municipal Code, Development Regulations. � , �� W.I. Realty Acquisition Corp. ES-3569.01 November 20, 2013 Page 2 Updated April 21, 2015 Proiect Descriation Based on the project information provided to us, we understand the subject site will be developed with an at-grade five-level hotel facility with an adjoining outdoor parking lot structure. The parking lot structure will be cut into the sloped topog�aphy to the east up to approximately six to eight feet. The western portions of the site are relatively level (proposed hotel building location) with moderate to steep slopes throughout the eastern portions of the � site. Approximately 2,181 square feet of the proposed hotel facility and associated parking I, area will encroach into the steeply sloped areas. Based upon visual slope reconnaissance, historic excavation activity has occurred on-site and has created the majority of the steep portions of the site. Based on preliminary plans, the majority of the hotel facility would be estabfished along the Lake Washington Boulevard (west) frontage and outside of the steep slape areas. Based on the referenced architectural plans, excavations of up to six to eight feet will be necessary to accommodate the alignment of the proposed parking lot structure re4ative to the east ascending grade changes. The proposed hotel structure is anticipated to consist of four stories of wood framing constructed over a podium post-tensioned slab. Based on past experience with similar structures, we an#icipate column loads associated with the concrete padium suppo�ted structu�e ta be on the order of 300 to 400 kips. The exterior parking areas wi(I likely incorporate retaining wall structures to support the necessary cuts. If the above design assumptians are incorrect or change, ESNW should be contacted to review the recommendations in this report. ESNW should review the final design to verify the geotechnical recommendations provided in this report have been incorporated into the plans. SITE CONDITIONS Surface The subject site is located west of Interstate 405 at approximately 1250 Lake Washington Boulevard North in Renton, Washington, as illustrated on the Vicinity Map (Plate 1). The site consists of two commerciai tax parcels (King County parcel numbers 082305905604 and 334450000602) totaling approximately 2.89 acres of land area. The site is bordered to the west by Lake Washington Boulevard North, to the north by an undeveloped lot, to the east by Interstate 405 and to the south Northeast Park Drive. The majority of the site is undeveloped; however, the western portion of the site currently consists of a gravel-surfaced parking lot. The western portions of the site are relatively level (proposed hotel building location) with moderate to steep slopes throughout the eastern portions of the site. Based upon visual slope reconnaissance and aerial photograph review, historic excavation activity has occurred on-site and has created the majority of the steep portions of the site. The steep slopes immediately east of the existing gravel-surfaced parking lot are in excess of 40 percent in some areas, The majority of the site and site slopes are vegetated with trees. saplings, and brambles. Earth So��tio°s Ntir�! LL� � '� - W.I. Reaity Acquisition Corp. ES-3569.01 November 20, 2013 Page 3 Updated April 21, 2015 Slope Reconnaissance/Stability Assessment During our fieldwork, we performed a visual slope reconnaissance across portions of the steep slope areas of the site. The main focus of our reconnaissance was to identify signs of instability or erosion hazards along the site slopes. The typical instability indicators include such features as head scarps, tension cracks, hummocky terrain, groundwater seeps along the surface and erosion features such as gulleys and rills. During the slope reconnaissance, no signs of recent, large scale erosion or slope instability were observed. Signs of previous excavation activity such as steep to near vertical reliefs were observed. Based on the observed steep to near vertica! reliefs as well as data obtained during our subsurface exploration, the site soils exhibit good soil strength characteristics. In general, based on the slope reconnaissance, stability of the slope areas of the property can be characterized as good. The planned outdoor parking lot structures incorporating structural retaining wall elements will effectively improve overall site stability and support at the base of the slope. Aerial Photograph Review A series of aerial photographs (ca. 1951 to 1970) were reviewed as part of our overall assessment of site stabiliry. The aerial photos are provided in Appendix C of this study. As depicted in the aerial photos, the site and surrounding areas were modified and cut, producing the areas of steep topog�aphy that currently exist throughout the eastern portions of the site. Based on our review, in spite of the extent of historic modifications and steep slope creation, overall stability is characterized as good. The stable conditions that exist are a reflection of the high strength characteristics of the underlying geology. The subsurface data (and Standard Penetration Blow Count data) collected as part of our subsurface investigation support this finding. The results of numerical slope stability analyses presented later in this study also demonstrate averall good existing site stability. Subsurface Five borings were advanced using a drill rig and operator retained by ESfUW in October 2014 to assess soil and groundwater conditions. Six test pits were also excavated by an excavator and operator retained by ESNW in October 2014. The approximate locations of the borings and test pits are depicted on the Boring and Test Pit Location Plan (Plate 2). Please refer to the boring and test pit logs provided in Appendix A for a more detailed description of the subsurface conditions. Topsoil In the undeveloped portions of the site, topsoil was observed in the upper approximately six inches. The topsoil was characterized by dark brown color and the presence of fine organic material. Eartn So�utio:^.s NIN,LLC �� W.I. Realty Acquisition Corp. ES-3569.01 November 20, 2013 Page 4 Updated Aprii 21, 2015 Fill Existing fill was encountered within the existing gravel-surfaced parking lot (west frontage) portion of the site. The existing fill extended to a maximum depth of approximately six to seven feet below existing grade at boring location B-1 (located near the Lake Washington Boulevard North frontage). The existing fill primarily consisted of loose silty sand material. Existing fill should be anticipated within the existing gravel-surfaced parking lot portion of the site. Native Soil Underlying the topsoil and fill, native soils consisting primarily of inedium dense to dense silt (Unified Soil Classification ML), silty sand (SM), poorly graded sand (SP), and poorly graded sand with silt (SP-SM) deposits were encountered extending to the maximum exploration depth of 41 feet below existing grades. Geologic Setting The referenced geologic map resource indicates the site is underlain by pre-Fraser silt and sand deposits. The native soil conditions observed at the test pit iocations are generalty consistent with the geologic mapping. The National Resources Consenration Service (NRCS) Soil Survey identifies the majority of the site as Alderwood and Kitsap soils: with urban land mapped along the western portion of the , site. The soil conditions observed are generally consistent with the NRCS designation. Groundwater Groundwater seepage was observed at all boring locations during our fieldwork in October 2014 at depths of approximately 19 to 35 feet below existing grades. Locally shallow perched seepage was also obsenred at boring locations B-1 and B-5 (western portion of the site) at depths of approximately nine feet and five and one-half feet, respectively. To further evaluate groundwater conditions, piezometers were installed at boring locations B-1 and B-2. In our opinion, the groundwater level observed at boring location B-2 (15.5 feet below existing grade) likely represents the local groundwater tab(e. The proposed building will be constructed at a finish floor elevation of approximately elevation 42 feet and will not extend into the local groundwater table elevation. However, localized zones of perched seepage should be anticipated in the excavations for the outdoor parking lot structures as well as utility excavations throughout the western partion of the site. Given the very dense and competent nature of the native soil deposits, we do not expect discrete groundwater seepage zones will adversely impact excavation stability, provided appropriate slope layback or shoring methods are utilized. E2r.� So,�t o�s NVv '�L;, _� , '� 1 W.I. Realty Acquisition Corp. ES-3569.01 November 20, 2Q13 Page 5 Updated April 21, 2015 Groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the #ime of year, and soil conditions. In general, groundwater flow rates are higher during the wetter, winter and early spring months. Seasonal Groundwater Monitoring As previously described, two groundwater monitoring wells were installed to monitor the I seasonal groundwater levels in the vicinity of the proposed hotel structure at boring locations B- 1 and B-2. ESNW has been observing the groundwater levels at the monitoring wells on a biweekly basis to establish the local seasonal high groundwater levels. The fol{owing table displays the groundwater levels observed to date. Maniott Residence Inn G�oundwater Monitoring Data Location B-1 B-2 Surface Elevation (ft.}' ` 42 � A9 � Date Groundwater Depth I Elevation (ft.)' Groundwater Depth ! Elevation �ft.)' ' 10/29/2014 8.33 33.67 i 9.25 29.75 ' 11/10/2014 8.33 33.67 �9.25 I 29.75 11/25/2014 5.00 34.Q0 19.00 30.00 12112/2014 7.83 34.17 18.50 30.50 12/24l2014 7.50 34.50 �8.17 30.83 1/6/2015 8.00 34.00 18.00 31.00 � 1/19I2015 7.33 34.67 18.00 31.00 ? 1/29/2015 7.42 34.58 18.00 31.00 � 2/10/2015 5.5Q 36.50 16.67 32.33 2/24/2015 7.50 34.50 16.17 32.83 3/10/2015 8.25 33.75 16.00 33.00 ' 3/24/2015 5.83 36.17 t 5.25 33.75 4/7/2015 7.50 34 50 17 00 32 Od *All ciepths and elevations are approximate Note: Seasonal high levels are bold and iialicized Based on the groundwater conditions observed during our subsurface exploration, the groundwater levels obsenred at baring location B-2 likely represents the lacal groundwater table elevation and the groundwater fevels observed at boring tocation B-1 likely represents a shallow perched seepage zone. CRITICAL AREAS AND GEOLOGIC HAZARDOUS AREAS ASSESSMENT As part of this geotechnical engineering study and critical areas report, the section 4-3-050 of the Renton Municipal Code was reviewed. Per the Renton Municipal Code requirements, the following topics related to development plans and site conditions are addressed Earth Solut�ons NbV L:C W.I. Realty Acquisition Corp. ES-3569.01 November 20, 2013 Page 6 Updated April 21, 2015 Site and Canstruction Plans Construction of a new five-level hatel facility, outdoor parkin� lot structure, and associated improvements is pianned. We understand the building pad wiil be located along the take Washington Boulevard North (west) frontage. Based on the referenced preliminary plans, we antic�pate the building pad elevation will aiign approxima#ely with the existing roadway elevation of Lake Washington Boulevard North. We anticipate the maximum cuts for the proposed �I development wri(1 be on the order of six to eight feet in order to construct outdoor pa�king lot structures to the east of the new hotel facility, as illustrated an Cross Sections A—A' and B — B' (Plates 3 and 4). Approximatefy 2,181 square feet of the proposed facility will encraach into the � designa#ed steep slape area on the east side of the site. Based on the results of this study, overall stability of the moderate to steep slope areas can be character�zed as good. ; Landslide Hazard With respect to landslide hazard areas, Part �-3-050J-1 C of the Ci#y of Renton Cr�tica! Areas i Regulations defines landslide hazard areas as the following i • Low Landslide Hazard: Areas with slopes less than 15 percent. • Medium Landslide Hazard: Areas with slopes between 15 percent and 40 percent and underlain by soils that consist largely of sand, gravel o� g!acial till. � • High Landslide Hazards: Areas with slopes greater than 40 �ercent and areas with slopes between 15 percent and 40 percent and underlain by soils consisting largely af silt and clay. • Very High Landslide Hazards: Areas of known mappable landslide deposits. The steep slopes thraughout the eastern portions of the site exhibit moderate to high landslide hazard characteristics, as defined by the City of Renton Critical Rreas Regulations, based on a greater than 40°!o slope condition. However, the slopes are underlain primarily by dense to very dense silt and sand soil, and were created through previous land modification activities (see aerial photas — Appendix C). As previously described in #he Slope Reconnaissance and Aenal Photograph Review sections of this study, in spite of the extent af historic modifications and steep slope creation, overall stability is characterized as good. The stable conditions that exist are a reflection of the high strength characteristics of the underlying geo�ogy. Steep Slopes With respect to steep slope areas, Part 4-3-050B-1c of the City of Renton Critical Areas Regulations defines steep slope areas as the follawing: • Sensitive Slopes: Areas with slopes between 25 percent and 40 �ercert. • Pratected Slopes: Areas with slopes greater than 4Q percent. Earth Solutions MN,lLC ; � t:� W.I. Realty Acquisition Corp. ES-3569.01 November 20, 2�13 Page 7 Updated April 21, 2015 Based on our observations, review of the referenced topographic survey, and as demonstrated by the City of Renton GIS data, sensitive and protected slopes are p�esent through the eastern portions of the property. Based upon visual slope reconnaissance, in our opinion, previous excavation activity has occurred on-site which created portions of the steep slopes to near vertical reliefs through the eastern portions of the property. Based on the identified subsurface conditions and site reconnaissance; the overall stability of the slope areas can be characterized as good. Erosion Hazard With respect to erosion hazard areas, Part 4-3-050J-1 c of the City of Renton Critica! Areas Regulations defines erosion hazard areas as the following: • Low Erosion Hazard: Areas with soils characterized by the Natural Resource Conservation Service as having slight or moderate erosion potential, and that slope less than 15 percent. • High Erosion Hazard: Areas with soils characterized by the Natural Resource Conservation Service as having severe or very severe erosion potentiai, and that slope more steeply than 15 percent. The majority of the existing slope areas would be classified as a high erosion hazard, as defined by ihe City of Renton Critical Areas Regulations, based on the National Resource Conservation Service soil designation and on-site slopes. Based on our site reconnaissance work, there is no evidence of widespread severe erosion activity throughou# the site. In our opinion, the planned development will not increase the erosion hazard at the site, provided appropriate Best Management Practices are impMemented during the earthwork and development activities. General guidelines for erosion control are provided in the Site Preparafion and Earthwork sectian of this study. Numerical Sloae Stability Analvsis Analysis of existing slope stability (static and seismic} was completed as part of our overall evaluation of site condi#ions. The slope stability analysis focused on the steep slopes present throughout the eastern portions of the site. Representative cross-sections (A-A' and B-B') were developed through the eastern slope areas of the site for purposes of evaluating stability. The cross sections are illustrated on Plates 3 and 4 of this study. A limit equilibrium computer modeling program (Slope-V1� was used to model the slope stability along the easteriy segment of Cross Section B-B'. The computer modeling software models slope stability based on soil strength parameters and groundwater conditions that the user inputs. The soil strength parameters used in the analysis were based in part on the observed soil conditions, Standard Penetration blow count data, and engineering judgment. The following table provides the soil strength parameters used for the slope stability analyses: �a�� Scl,;tio�s NVv' LLC W.I. Realty Acquisition Corp. ES-3569.41 November 20, 2013 Page 8 Updated April 21, 2015 Saturated Unit Moist Unit Friction Cohesion Soil Type Weight We19ht Angle Intercept (Pcfl �P�� (degreesl (PS�) Med. Dense / 135 125 34 0 Dense SM V. Dense MUSM 135 125 32 550 V. Dense Sand 125 120 38 0 The soil strength parameters assumed in the analysis are considered conservative based on the observed soil conditions and Standard Penetration blow count data acquired at the boring locations. In any case, the Slope-W stability analysis provides a theoretical factor-of-safety with respect to stability of the slope evaluated. In general, a static factor-of-safety of at least 1.5 and a seismic factor-of-safety of at least 1.2 are considered acceptable. With respect to seismic loading, and based on review of local mapping of peak ground acceleration, a conservative lateral seismic coefficient of 0.3g was used for the seismic stability analysis. It should be noted that the mapped peak ground acceleration for the site and surrounding area is approximately 0.44g. Based on the results of the slope stability analysis, the static factor-of-safety exceeded 1.5 and the seismic factor-of-safety was at least 1.2, indicating acceptable overall site stability. The results of the stability analysis and accompanying computer output are provided in Appendix D. While the results of the slope stability analysis indicate an adequate factor-of-safety for deep- seated rotational failure, the potential for relatively shailow debris flow type failures does exist. Although no areas of historic debris flow activity were identified as part of our site investigation and fieldwork, the potential does exist, and is common for most sloped topographic settings. With respect to the existing slope areas of the site that will remain unaltered as part of the proposed development, maintaining the current vegetative cover that currently exists on the slopes will help mitigate the potential for shallow debris flow events. Based on the findings of the subsurface investigation, slope reconnaissance, and results of the slope stability analysis, the site slopes are considered to possess an acceptable level of stability. Provided the proposed construction and related excavation activities are performed in accordance with the recommendations of this study, it is our opinion the proposed development will not adversely impact the existing slopes or increase the potential for slope instability, Ec^.h S�I�;�o^c NVd LLC � I � W.I. Realty Acquisition Corp. ES-3569.01 November 20, 2013 Page 9 Updated April 21, 2015 Analysis of Proposal The planned development activity will involve grading and construction of a new six-level hotel facility, outdoor parking lot structures, and associated improvements. The proposed development activity will include maximum excavations of approximately 6 to 8 feet withi� moderate to steep slope areas throughout the eastem portions of the property in order to construct the proposed outdoor parking lot structures. Based on the referenced slope � encroachment exhibit, the total steep slope encroachment area for the proposed structures wil! be 2,181 square feet. As previously described, the site soils exhibit good strength characteristics and site slopes exhibit good stability, and in our opinion, portions of the steep slopes were previously excavated to the current condition. The proposed development activity, in our opinion, is feasible from a geotechnical standpoint, and "(i). The proposal will not increase the threat of the geological hazard to adjacent or abutting properties beyond pre- development conditions; and (ii). The proposal will not adversely impact other critical areas; and (iii). The development can be safely accommodated on the site." DISCUSSION AND RECOMMENDATIONS Generat In our opinion, constructicn of the proposed Five- evel hote'. facility, outdoor parking lot structure. and associated improvements at this site is feasible from a geotechnical standpoint. Loose soil deposits are present to varying depths throughout the western portions of the proposed building site. Given the proposed construction and foundation loads, these upper soil deposits in the western portions of the proposed building location are not suitable for support of foundat+ons. The depth to the competent native soil deposits is estimated to be on the order of up to 20 feet below existing site grades (and possibly deeper at some locations). In our opinion, the proposed building structure can be supported on conventional spread and continuous footings bearing on competent native soils where exposed along the base of the building excavations. Where loose upper deposits are exposed at the foundation subgrade elevation, overexcavation of the loose soil in foundation areas and replacement with crushed rock is recommended. Additionally, where the loose upper deposits are found to extend more than approximately five feet below the proposed foundation subgrade elevation, the use of aggregate piers in lieu of overexcavation and replacement may be more practical. Recommendations for foundations and preliminary guidelines for aggregate piers are provided in the Foundations section of this study. Excavations to accommodate the planned outdoor parking lot structures wilt require cuts of up to roughly six to eight feet. We anticipate the excavations will be completed using temporary slope excavations. Recommendations for temporary slope excavations, foundation design, and other pertinent geotechnical recommendations are provided in the following sections of this study. Ear.� Sc�ut��ns N�h� LLC j ; _ W.I. Realty Acquisition Corp. ES-3569.01 November 20, 2013 Page 10 Updated April 21, 2015 This study has been prepared for the exclusive use of W.I. Realty Acquisition Corp. and their representatives. No warranty, expressed or implied, is made. This study has been prepared in a manner consistent with the level of care and skill ordinarify exercised by other members of the profession currently practicing under similar conditions in this area. Site Preaaration and Earthwork The primary geotechnical considerations with respect to earthwork are related to the outdoor parking lot structure excavation, temporary slope construction, and foundation subgrade preparation for the main building structure. The soils encountered in the building excavations should largely consist of loose silt and sand deposits throughout the western portions of the proposed structure which transitions to medium dense to dense native deposits throughout the easte�n portions of the proposed structure. The native silt deposits can be characterized as having a generally moderate to high sensitivity to moisture. Excavations As excavation of the outdoor parking lot structure progresses, the soil relative density should generally increase and is expected to exhibit good stability in open cut excavations. Localized perched zones of groundwater seepage should be expected in the outdoor parking lot structure excavations. Overall stability of the excavation is anticipated to be good, provided appropriate means for sloping or shoring the excavation are utilized. Based on the soil conditions observeti at the test sites, the following allowable temporary slope inclinations can be used: • Loose to Medium Dense Native Soil 1H:1V (Horizontal:Vertical) � • Dense to Very Dense Native Soil* 0.5H:1V to 0.75H:1V** ' Based on data obtained during the subsurface exploration, the native silt soi(s should become dense to very dense at a depth of approximatety five feet below existing grades. " Steeper temporary slope inclinations of 0.25H:1V may be feasible based on actual conditions encountered, and based on observation and approval by the geotechnical engineer. The geotechnical engineer should observe the excavations and assess the allowable temporary slope inclination based on the soil and groundwater conditions exposed in the excavations. Supplement recommendations for sloping the excavations may be made by the geotechnical engineer based on conditions observed. Structural Fill We anticipate structura! fill placement will generally be required behind foundation walls and within utility trench excavations. Structural filt may also be necessary in slab-on-grade areas. Due to the building load and bearing capacity requirements, the building foundations should be founded directly on competent native soils, or two-inch crushed rock immediately underlain by competent native soils (where overexcavation in lieu of aggregate piers is utilized). Earth Solutions MN, LlC J � � W.I. Realty Acquisitio� Corp. ES-3569.01 I November 20, 2013 Page 11 ' Updated April 21, 2015 Where structural fill is utilized outside foundation areas, a suitable granular soil with a moisture content that is at or near the optimum level should be used. The native soils can be considered for use as structural filf provided the soil is at or near the optimum level at the time of placement. The native soils have a moderate to high sensitivity to moisture, and will become unstable if exposed to excessive moisture. If the native soils cannot be successfully compacted, the use of an imported soil may be necessary. Imported soil intended for use as structural fill should consist of a well graded granular soil with a moisture content that is at or near the optimum levei. During wet weather conditions, imported soil intended for use as structural fill should consist of a well graded granular soil with a fines content of five percent or less defined as the percent passing the #200 sieve, based on the minus three-quarter inch fraction. Structural fill is defined as compacted soil placed as wall backfill and in slab-on-grade, utility trench, and roadway areas. Soils placed in structural areas should be compacted to a rela#ive compaction of 90 percent, based on the maximum dry density as determined by the Modified Proctor Method {ASTM D-1557-02) and placed in maximum 12 inch lifts. In pavement areas, the upper 12 inches of the structural fill should be compacted to a relative compaction of at least 95 percent. As indicated above, structural fill placed below foundation elements should consist of two-inch crushed rvck immediately underlain by competent native soils. Erosion Control !n general, control of off-site erosion for this project will likely be lirnited to construction entrances. Silt fencing should be installed as appropriate, and as needed along the site perimeter. Construction entrances should consist of quarry spalls underlain by a non-woven filter fabric. Quarry spail thickness will depend on subgrade stability at the entrance, but should typically be at least six inches. Foundatians Based on the results of our study, the proposed hotel facility building can be supparted on conventional spread and continuous footings bearing on competent undisturbed dense to very dense native soil or aggregate piers. Where the upper loose soil deposits are relatively shallow (less than five feet), overexcavation of the loose soils and replacement with two inch crushed rock can be considered. Where areas of the existing loose deposits extend more than approximately five feet below the proposed foundation subgrade elevation, the use of aggregate piers in lieu of overexcavation and replacement may be more practical. Preliminary guidelines for aggregate piers are discussed in greater detail later in this section of the report. The extent of the deeper loose soil deposits should be further explored at the time of the building excavations. Based on the data collected at the boring locations, we anticipate a depth of approximately 20 feet to competent native soil within the vicinity of boring location B-1 which we anticipate to transition to near-surface competent soils at boring iocations B-2 and B-5. The 3oring and Test Pit Location Plan (Plate 2) illustrates an approximate area where we anticipate �ggregate pier ground improvement will be necessary. �a".� So u!�c�s NV�� lC ` '�� W.I. Realty Acquisition Corp. ES-3569.01 November 20, 2013 Page 12 Updated April 21, 2015 Assuming the foundations are supported on competent native soils, suitable crushed rock material, or aggregate piers the following parameters should be used for foundation design: • Allowable Soil Bearing Capacity 5,000 psf • Friction 0.40 . Pass:ve Res�stance 350 pcf (equivalent fluid) For short term wind and seismic !oading, a one-third increase in the allowable soil bearing capacity can be assumed. A factor-of-safety of one and one half has been applied to the friction and passive resistance values. With structural loading as expected, and assuming foundations are supported on competent native soils, crushed rock structural fill, or aggregate piers as described above, total setttement in the range of one inch is anticipated, with differential settlement of about one-half inch or less over the span of a typical column spacing. The majority of the settlements should occur during construction, as dead loads are applied. Aggregate Piers In our opinion, where the upper loose soil deposits are encountered to depths of greater than approximately five feet at the foundation subgrade elevation, the use of aggregate piers can be considered for support of the foundations, in lieu of overexcavation and replacement. Aggregate piers would replace the existing loose soils with a series of crushed rock columns. The building foundations would derive support along the crushed rock columns, mitigating the potential for excessive foundation settlements. A formal design for aggregate piers should be developed during the design phase of the project when the foundation plan and loading has been determined. In general, aggregate piers are constructed as follows: • Pier Diameter 24 to 30 inches (typical) • Pier Depth Varies. Extend to five feet into competent soils. • Installation Method Augered Holes. Casing should be anticipated. ,, • Aggregate Material Typically one to one and one-half inch crushed rock. • Pier Spacing Varies. Depends on soil conditions and foundation loads. • Cost Varies, but is typically less than piling (estimated $850/pier) ' Based on the subsurface conditions encountered at the boring and test pit locations, the western portions of the proposed building location generally were found to possess existing loose soil deposits to depths of approximately 20 feet or greater. Therefore, for preliminary I design purposes, it should be expected that these areas would require the use of aggregate � piers. � Earth Solutione NW,LLC 1 � � W.I. Realty Acquisition Corp. ES-3569.01 November 20, 2013 Page 13 Updated April 21, 2015 Slab-On-Grade Floors Slab-on-grade floors for the proposed building structure should be supported on competent native soil or a compacted structural fill subgrade, as appropriate. Unstable or yielding areas of the subgrade should be recompacted or overexcavated and replaced with suitable structural fill prior to construction of the slab. A capillary break consisting of a minimum of four inches of free draining crushed rock or gravel should be placed below the slab. The free-draining material should have a fines content of five percent or less (percent passing the #200 sieve, based on the minus three-quarter inch fraction). In areas where slab moisture is undesirable, installation of a vapor barrier below the slab should be considered. Sub-slab d�ainage is discussed in the Drainage section of this study. Retainin� Walts Retaining walls should be designed to resist earth pressures and any applicable surcharge loads. With respect to building and site retaining walls, the following values should be used for design: • Active Earth Pressure (Yielding Wall) 35 pcf (equivalent fluid / granular fill)"' • At-Rest Earth Pressure (Restrained Wall) 50 pcf • Traffic Surcharge (Passenger Vehicles) 70 psf (rectangular distribution) • Passive Resistance 350 pcf(equivalent fluid) • Allowable Soil Bearing Capacity 5,000 psf • Coe�cient of Friction 0.40 • Seismic surcharge (where applicable} 6H" �, 'The building foundation wali design should be further evaluated with respect to s?ope s��cnarge �cadi�g supplement design criteria should be prov�ded by the geotechn�cal engireer as approonate "Where H equals the reTained height I Drainage should be provided behind retaining walls such that hydrostatic pressures do not develop. If drainage is not provided, hydrostatic pressures should be included in the wall design, as appropriate. The geotechnical engineer should review retaining wall designs to confirm that appropriate earth pressure values have been incorporated into the design and to provide additional recommendations, as necessary. EaRh Solutions NW. �LC ! .�' W.I. Realty Acquisition Corp. ES-3569.01 November 20, 2013 Page 14 Updated April 21, 2015 Retaining walls should be backfilled with free-draining material that extends along the height of the wall, and a distance of at least eighteen inches behind the wall. The upper one foot of the wall backfill can consist of a less permeable (surface seal) soil, if desired. In lieu of free draining backfill, use of an approved sheet drain material can also be considered, based on the observed subsurface and groundwater conditions. The geotechnical engineer should review conditions at the time of construction and provide recommendations for sheet drain, as appropriate. A perforated drain pipe should be placed along the base of the wall, and connected to an appropriate discharge location. Where foundation walls are formed against the temporary shoring walls, a sheet drain and related waterproofing should be utilized. For site retaining walls receiving backfill, the reta+ning wall and drainage detail illustrated on Plate 5 should be considered. Excavations and Slopes The Federal and state Occupation Safety and Health Administration (OSHA/WISHA) classifies soils in terms of minimum safe slope inclinations. In our opinion, based on the soil conditions encountered during fieldwork for this site, the upper loose to medium dense native soils and fill encountered to depths of up to approximately 5 to 10 feet would be classified by OSHA/WISHA as Type B. Temporary slopes over four feet in height in Type B soils should be sloped at an inclination that is no steeper than 1H:1V. In our opinion, the dense to very dense native soils below approximately 5 to 10 feet below existing grades would be classified by OSHAMIISHA as Type A. Temporary slopes over four feet in height in Type A soils should be sloped at an inclination no steeper than 0.75H:1V. With respect to the proposed building excavations, temporary slopes inclined at 0.5H:1V (or steeper} are feasible within the very dense silt and sift�r sand deposits. The geotechnical engineer should observe the excavations to confirm the appropriate allowable temporary slope inclination. If the above slope gradients cannot be achieved, tempo�ary shoring may be required. Permanent slopes should maintain a gradient of 2H:1V, or flatter, and should be planted with an ; appropriate species of vegetation to enhance stability and to minimize erosion. I Seismic Considerations The 2012 IBC recognizes ASCE for seismic site class definitions. If the project will be permitted under the 2012 IBC, in accordance with Table 20.3-1 of ASCE, Minimum Design Loads for , Buildings and Other Structures, Site Class C, should be used for design. ! In our opinion, liquefaction susceptibility at this site is generally low. Along the westerly , (frontage) side of the property, a moderate susceptibility would exist in our opinion. Crushed rock and aggregate pier support of foundations would mitigate this risk. Earth Solutions NW,LLC f1� W.I. Realty Acquisition Corp. ES-3569.01 November 20, 2013 Page 15 Updated April 21, 2015 Draina�e The proposed building will be constructed at a finish floor elevation of approximately 42 feet and will not extend into the local groundwater table elevation. However, localized zones of perched seepage should be anticipated in the excavations for the outdoor parking lot structures as well as utility excavations throughout the western portion of the site. Groundwater should be anticipated in site excavations, Temporary measures to control surface water runoff and groundwater during construction would likely involve interceptor trenches and sumps. ESNW should be consulted during prefiminary grading to identify areas of seepage and to provide recommendations to reduce the potential for instability related to seepage affects. The geotechnical engineer should assess conditions during excavation activities and provide supplement recammendations for sub-slab drainage, as necessary. fn o�r opinion, foundation drains should be installed along perimeter footings of the buildings. A typical (shallow) foundation drain detail is provided as Plate 6. Infiitration Evaluation Based on the groundwater conditions observed at elevations close to the proposed building foundation elevations, in our opinion, infiltration should not be utilized as a storm drainage measure for the proposed project. Utility Support and Trench Backfill In our opinion, the soils anticipated to be exposed in utility excavations should generally be suitable for support of utilities. Existing fill, organic or highly compressible soils encountered in the trench excavations should not be used for supporting utilities. Moisture conditioning of the soils will likely be necessary prior to use as structural backfill. Utility trench backfill should be placed and compacted to 95 percent of the modified proctor, or to the applicable specifications , of the responsible utility district or jurisdiction. I LIMITATIONS I' The recommendations and conclusions provided in this geotechnical engineering study are professional opinions consistent with the level of care and skill that is typical of other members ', in the profession currently practicing under similar conditions in this area. A warranty is not I expressed or implied. Variations in the soil and groundwater conditions observed at the test I locations may exist, and may not become evident until construction. ESNW should reevaluate the conclusions in this geotechnical engineering study if variations are encountered. Additional Services ESNW should have an opportunity to review the final des�gn with respect to +�e geotechnical �ecommendations provided in this report. ESNW should also be reta;ned to prov�de testing and �onsultation services during construction. Ea^!` colu'ion5 NVd '_�v � X r__ s:�. _ r�- -. s - - _ - ] � . � �j s �}L- •I�C.7t 4hj � � �_� . T� '" v ,(Fr- ;' � A�� •: •;?. ' - _ =`a ; 'i . - �� x ,� .�_.__.__.._.,_._,._.._... �, S �-� � . � J . c,� •* � �• �� i 4it1 �t °'I_ �i_ _ �'.y`Y'' -�� {u�'t �> 3T .?. ' �r�L. 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No. 3569.01 vOTE:This plate may cantain areas oi coloc ESNW cannot be �esponsible for any subs�uent misinterpretation of the information CheCked HTW Date April 2015 Plate 1 resuttir�from black&white reproductions of this plate. , i ! 70 .� e�1 � , - � _, NORTH a � '�: c c �: A, o � � � � — o � �, � U � U TP-4 i J a�i L � _ � � a � � � � � ~ �o � � 0 30 60 120 � •� � > � � m � � c� c� � B_2•— ��–s� Scale in Feet a�� . — .` z TP_3 O � -- m ,� i B-� Z A LEGEND 1 1 :i B-1—•—Approximate Location of � __ ESNW Boring,. Proj. No. , -,.� B -__ , . _ _, ES-3569, Oct. 2014 . - , �� • ;- ' , B-� _ f . , " . � _�� . � ' ,` TP-1--•—Approximate Location of < B-3 �' -��` ESNW Test Pit, Proj. No. - �' B' �- .�.'� ;� ES-3569. Oct. 2014 - . —,_ ,.��,� TP-2 TP-1 • - � - � _ _ '% , Subject Site � . s - � - . _;_ TP-5 -,;�� ' 90 a Proposed Building B-5 � -_'_ 'j _ -" � -� �� Cross Section Line y: �: , ; . _ - _ - (See Plates 3 � 4) : , � _ _ , _ _ _�- ; � � � �- � " � . � -. Anticipated Approximate - TP$'i � ; Extent of Ground Improvement � � " = (Aggregate Piers) � � �� /l. �+/ I ". � ' � : / i / . . { .'�/:. �/ " _ " 1 : f .� . ' ' . ,�f � -f ,.. , � f - �� s '�� NOTE`he graphics shown on this plate are not:ntended for design Drwn. By ` r .: '�'; : �� r� ' � purposes or pre�ise scale measurements,but only to illustrate the GLS ` � : , i � . ! � -- '� approximate tes!locations rela5ve to the approximate locations of Checked By f �` � t r = ' enis6ng and i or proposed site features.The infomiation iAustrated � �� tt ' � � � � ! is largely based on data provided by the d�nt at the time ot�r H� � ''�� ' '��' �'` ' � study.ESNW canrwi be re�onsible for subsequent desgn changes Date . �' � '`. �.`' l4 3 1 _ �;��t�_--- - - or interpretation of the data by others. 04/20/2015 . Proj. No. N07E:This plax may contain areas of cobr ESNW cannot be res�nsible for 3ny subsequent misinterpretation of the informa6on 3569.01 resul6ng from b adc 8 white repraductions of thfs plate Plate ,, 2 ,. �i A A' _ Q � o 100 - 100 � � � U � C � L O -p tn :� •— ta Proposed Hotel Building � � � - ---------- --- . _ _ -- - — -- c -- - � � o 75 �re�au rp.a ar�t r rrw� tso��,�3-+on Bs�si 75 p -` C U � �' TP-4 g � SN4' � �� 34 W _ _ — � �:�• W u. ' 'Bonno B-3 O`fset 9'4W; SM. ML / '-� "` SZ u- 50 TeSi Pa-?-s o^se�+s n h� B'3 / az 50 z TP-3 l � io � � 6, Z � ;sa��a- ,�t 3= sE — i _ �, ss � O B-1 '— w � Lo�,_FlLL _ _ � � so;s � ' ��- Q 7--, ' �- � J �.�- SM, ML ,s � i SP, SP-SM ��' u�,. w -'_6 „ � � w 25 ,6 SM, ML �' r ' �� 25 _ ' l •� 503' / � - so�a 7 _ _. _, _.-- — —' �f � SP, SP-SM - - - -� ._.. , _ _.. — ____ -- - � � �y �Y __ NOTE:The graph;cs shown on th,s p�ate are not mte�ded for design purposes or prease scale rr�asurements,but only to iilustrate the approximate test bcatrons relative to the approximate locations of exis6ng and 1 or proposed site features.The information illustrated ' is Iargely based on data provided by the ct+ent at the time of our � 0 25 50 study.ESNW cannot be res�orrsible for subsequent design chan�s Horizontal Scale � � '— or Interpretation of the data by others. �• - 25� Scale in Feet Drwn. By NOTE:The stratfiqbon lines shown on this cross section represent GLS the approxirr�te boundaries betv�en soil types.The actual transitions Checked By 0 25 50 may be either more gradual ar more severe.They are based on our H� Verticel Scale � � interpretation of the subsurface canditions encountered at the individual 1" = 25' Scale in Feet test locabons and our judgement and experience.ESNW cannot be Date responsiole for E^�e mterp-eta5on of the data by othe�s 04/20/2015 Proj. No. NOTE:This p�ate may conta n a�eas o!cofoc ESNW cannot be 3569.01 respons�ble for any subseque�t m�sinterpretatr�n of the information resu!t�ng from biack 8�white reproduc'.ions of this riate. Plate 3 �' i � g g' � m � o 100 Proposed 100 � � � Retaining Wall m � .c c a� s Proposed � ° � v � � � Hotel Building ;Bo�,.,9 g-3 0�,zo.N, � _ ____ _ ____ B-3 � c 75 Zs 75 O '� � SM, ML � SM. ML U � � Drive Lane/ � Walkway ss _ -- � t= Was Z i w �JQ .��'es:P�t?a. t 15'S1 7 _ _� �"_ 7 —�3 — '__ � — _� � � /, rJ� I� Tes �;iF-2 Onsel[5 S;,S�:�g B-5�p5el fi0 5� TP- O9cnrg B-'�++B-1 y� TP-2 B-5 ,� s�a�s- SP. SP-SM p sr;,. H 7 6 � 5`"�5� / � � Loose, FILL 5 ,-- 2� �� SP, SP-SM � 25 � � 27 �/�' -25 ', ,� SM, ML / � � � ' 50 7 v � � - SC�4' �� /• � �— � � � SP, SP-SM 0- p + , � ' NOTE:The graph�cs shown on this plate are not intended fo�design purposes or prec+se scale measurements,but only to iilustrate the approximate test locatbns relaUve to the approximate loca�ns of existing and(or proposed site features.The informaUon iilushated is largely based on data provided by the dient at tt�time of our 0 25 50 study.ESNW cannot be responsible for subsequent cksgn changes Horizontal Scale � � or interpretation of the data by others. �^ =2g� Scale in Feet Drwn. By NOTE:TF�stradfication iines shown on this cross section represent GLS the appro�imate boundaries beMreen soil types.The actual Vansitions CheCked By 0 25 50 may be either more gradual or more severe.T1�ey are based on our H� Vertica) Scale � � �nte�retation of the subsurface conditans encounte�ed at the individual 1" =25' Scale in Feet test la:aaons and ourjudgement and experience.ESNW cannot be Date ' responsib�for the interp2tatior.of the data by others. 04/20/2015 Proj. No. NOTE:This plate may conta�r areas of calor.ESNW c�nnot be 3569.01 respons'rble fo�any subseque�t mis;nterpretation of the information resulting from black d white rep�oductions of this plate. Plate 4 i c �i i 18" Min. 6 0 O O O O /1 O 0 O(''� O� o � � � � � O� o Q q,�G�a� c O o o� � o V p, o � �0 0 0 , 4 �o ° � �' O�o` o Q� �0 4 a � e oo a e 0 q GO o pO� '0 0 o O e o � �000 � O000000po � o 00 0 0� p� 0 0 �Q o O p O o o D o 0 - 00 o Go �� `� o lo o e o �o � O o (J � ° � � ° ° Structural ° `� o p o � o e o c ' o e Q Oo O �� o 000 �o0 4 � Fi1l ao 0 0 00 ^vp p � �oOo Do oO o o a o V o �e o �� o o C o�O a e o 0 0 0 � o o � 0 D o o O �O e oo � Q o 0 0 o Q ^ o p o o� o 0 o il o � o � e 7S I I ( _ � I I - '� O � o Qo Q e C 9 _ r g �L Oo�c f I , o o � : '~'' : f i, •ti: : ti% fti � ti.ti. � Perforated Drain Pipe NOTES; {Surround 1n Drain Rock) , • Free Draining Bac�ll should consist of soil having less than 5 percent fines Percent passing#4 should be 25 to � 75 percent. , • Sheet Drain may be feasible in lieu SCHEMATIC ONLY - NOT TO SCALE ��, of Free Draining Backfiil, per ESNW recommendations. • Drain Pipe should consist of perforated, rigid PVC Pipe surrounded with 1" I Drain Rock. i LEGEND: , » ,�� ', d t 0 oa 4� Free Draining Stnictural Backfill ` � � _�� ` . . {f.t�t. ..:::.-. 'i .ti•'s.'L �� w'fti:ti:;,:' 1 inch Drain Rock RETAINING WALL DRAINAGE DETAIL •f•r�t. Marriott Residence {nn Renton, Washington , Drwn. GLS Date 04/07/2015 Proj. No. 3569.01 Checked HTW Date Apri12016 Plate 5 I'� �� a, � Slope �--� � ::: 't$":fMiri.:?:::: : .•�'.�. . . � ti'~'~'��~� '^-�-""' ..r.r•r•r•r•t f ,r . .fti.�..�j:j,L f: ..... ,rr' �rti' ~f'�.4� • if:.~• •4f� f --'�— f � f 2° (Mln.; ! Pertorated Rigid Drain Pipe (Surround with 1" Rock) NOTES: • Da IVO7 tie roof downspouts to Footing Drain. SCHEMATIC ONLY- NOT TO SCA�E • Surface Seal to consis#of 12"of less Qermeable, suitable soil. Slope away f�om building LEGEND: �� Surface Seai; native soil or other low permeability material. � � ; � _ f".'j"". "'�� 1•4•ti�t•� . i�� . i 1' �.�•l•.'.1'; n �`� .. III . E • ..I..i .4f;j;r�� 1 Drain Rock � < ��'�ti��'�j �: e..� FOOTING DRAIN QETAIL Marriott Residence Inn Renton, Washingtan Drvvn. GLS Date 04/07/2016 Proj. No. 3569.01 Checked HTW Date April 2016 Plate 6 �1�}-- Appendix A Subsurface Exploration ES-3569.01 The subsurface conditions at the site were explored by advancing �ve borings and excavating six test pits across accessible and representative portions of the property. The subsurface ' explorations were completed in October 2014. The approximate boring and test pit locations are illustrated on Plate 2 of this report. Logs of the borings and test pits are provided in this Appendix. Earth Solutions NW,LLC / G�� Earth Solutions NWLLC SOIL CLASSIFIGATI�N CHART MAJOR DIVISIONS SYMBOLS TYPICAI GRAPH LETTER DESCRiPT10NS . CIEAN '� �' �u-G�ED GRAVELS,GRAVEI- GRAYEL GRAVELS ' ��• � G� SAND MIXTURES,trrr�oa No AND ��•� F�r�s GRAVELLY J�`';� POORLY-GRADED GRAVELS, soi�.s °a` �° (LITTLE CR NO FINES) o pG�, p Gp GRAVEI-SAND MIXTURES,LITTLE �,l�o{} OR NO FINES COARSE ° GRAlNED GRAVEIS WITH '� '' ' sE�rY cRnvE�s.c�,avEt-s�wo- SO{lS MORE THAN 5055 FINES o 4 GM SILT MiXTURES OF COARSE � o FRACTIflN RETAINED ON NO. a SIEVE (APPRECU+BIE G.0 CiAYEY GRRVELS.GRAVEI-SANO- AMOUN'f OF FINES; CIRY MtXTttRES CLEAt1 SANDS SW WELLI3RACED SANaS.GRAVELLY ��gb SAND SANDS,LITILE OR NO�INES o�rHa�Rin�is AND LARGER THAN SANDY NO_2�S�EVE SOILS POORLY-GRAdED SANDS, S1ZE t��E�►��FfNES) sP GRAVELLY SAND,LtTTLE�2 NO FINES SANOS W lTH s��v s,aNps.sa�r�o-s�� MORE 7}1AN 50% FINES SM �+txTu�s OF CCARSE FRACTION PASSING ON NO. 4 gt� (APPRECIABLE SG. CUYEX SJWDS,SAND-CiAY Al�AOUNT OF FfNES) MiXTURES G i ' �IORGANIG S1LTS AND VERY FIi� � � ( �L SANDS.ROCK FLOUR,SiLTY OR � CLAYEY FINE SANDS OR GAYEY 51LTS W(TM S�IGHT PLASTiCITY f�i tN�2GANiC CLAYS dF LOW T4 SIITS �" �- FINE �a UQtJID UM'C ��ii%f/r CL MERII�A ACASTtCi'TY.GRAVELLY GRAINED ClAYS �ss'tww sa � ,.,f uYs,�C�vss.sr�rr SOil5 — Eart�Soiu6ons NW BORING NUMBER B-1 � 1805-136th Ptace N.E.,Suite 201 � ' BeUevue,Washington 98005 PAGE 1 OF 2 Te�eph one: 425�49-4704 Fax 425�49-4711 IENT W i Reatty ACqu+sition Corv,. __ PROJECT NAME Marr;ott Residence Inn OJEC7 NUMBER 3569�____ _ PROJECT LOCATION Renton Washin�ton_ _ ----_ _�_�_�___— __ - -- -- DATE STARTED 10/6/14 COMPIETED i0/6l14 GROUND ELEVA7iON 38 fi HOIE SIZE _ DF�LLINt3 CONTRACTOR Boretec GROUND WATER LEVELS: DRIL�ING METHOD HSA �AT T1ME OF DRILLING 23.0 ft/Elev 15.0 R IOGGED BY HTW CHECKED BY HTW AT END OF DRILUNG __--_ _ NOTES Gravel AfTER DRILIIN� - w o + = tr-w � �H� ! N I=C� � a� �� j ' �j Q TESTS � �d O MATERIAL DESCRIPTION �v �Z v mOZ ? j�� w -- �c� � � 0 � Dark brovm silty SAND wfth gravel, bose. moist(Fil) SM -�;' 2.0 _�-- -- - �,o _- _--- - Brown sitty SAND, �oose,moist(Filq SS 100 5{6 3 MC= 10.50% � �� — - � � SM 5 , 7--�— - SS 100 3�5�3 MC= 13.10% � _.�___ _--------- 7 0 — --- - 31 0 ; -- Brown silty SAND.bose, moist to wet SS 100 �6)3 MC=20.80% ' ` _ . ___ _ _ -- SM � t0 1 ' -heavy seepage �— � �- - -- � ---- -�� j i T SS 100 3�6�3 MC=15.0096 f � ��o __ 2�.0 � _ - - —_ __ ' Tan SILT, loose to medium dense,wet to saturated � i 'I �� i _ I � i � I � � � � � , , �, 16 I � _ _,_ --- � �7_g Ml I � SS 100 (16) MC=28.10% ; ; a' � � -- - _�. --- � J � � � � ' � ' 1 m ' n� " � i -increasing gravel c�tent � ! „ � 20 ' � zoo �ao ,c�►,�,��PB�, !1�" i Earth Soiutions NW BORING NUMBER B-� I 1$05-736th Place N.E,Suite 20� I ' . ' ' Bellevue,Washington 98OOS PAGE 2 OF 2 I Teic�hone: 425-449-4704 � F3x- 425-A49-4711 � IENT W L Realty Acqu�sifion Corp_ PRO.l�CT NAME Marriott ResWencE tnn __ �'� dJECT NUMBER 3569 _ PROJECT LOCATtON Renton;Washington ' �w � � � I � r � vsw '; � c) _ d� ` �� j ��Q E TESTS � n-O hAATERIAL D�SCRIPTION �v � �Z � U ' mOZ j � �'� , Q � C7 � � 20 , SS 100 40-50f3" MC=9.50% Gray silty SAND with gravei,very dense moist[Tiit) 'e�___ _ _____ __---, -►natt3ed coloring SM 25 -lense of dean sand :x SS 1� 50t4" MC=9,50°,� ' � 2s.s -�comes saturated ,2 s �_ ____ _ _ _________ __ Bonng termmated at 25 5 feet below existing grade.Groundwater seepage encounierea at 9.5 feet and groundwater tabte encauntered at 23.fl feet beiow ex�sting grade.2"PVC stanapipe instailed to 25_5 feet 5.J to 15 0 fee:slotted Bonng backfilied with bentonite chips and sand Bottom af ho(e at 25 5 feet 1 { � Y � II{.� � I i � a � � J I � I _ �. 4J Q" W 2 � U" � t: �4 , Eart�Solutions KW BORING NUMBER B-2 1805-136th Place N.E.,Suite 201 PAGE ? OF 2 � ' Setlevue,Washington 9$005 Te lephon e: 425�4d9-47fl4 Fdx: 425�49-4711 �IENT W I Reaity AcquisRion Co�p__�__. PROJECT NAME AAarriott Residenoe_Inn OJECT NUMBER 3569 __ __� , __ PROJECT L�CATtON _Renton,W85hington_ __ __ _---- - - - DATE STARTED i0tGJ14 COMPIETED 10t6114 GROUND ELEVATtON 49 ft HOIE SIZE DR1LLtNG CONTRACTOR Boretec GROUND WATER LEVELS: DR1LlING iAETHOD HSA �AT T1ME OF DRILUNG 19.0 ft/E1ev 30.0 R __ _ __ I�GGED BY DAM CHECKED BY HTW AT ENd af DRILtJNG - NOTES Bramb�s AFTER ORI�UNG - p � � ; � o �_ � �u�i � �r� � 'v �� ' �� , a? � ��j TESTS � i�J� MATERIAL DESCRIPTION � ; �z � W Uz � c9 � � � � � � € j •, Brown sl�ty SAND with graveL toose to medium dense,dry to damp I � # � E � . -becomes medium�ense : � f - _ - � - : � � �� 1� 12-10-10 MG= 1�.10% : {2p} � i__.__ _ _ --— � -becomes dense to vesy derse ��_ -- __- I ; � � _ SS 100 8�3�y 3 hFC=9.10°!0 � _ E � i ; � ; _ ---_rt. _ i m.,.,m,_�___ ' � • �4-14-15 0 � � -becomes damp t8 mast � ` SS 104 (29) MC= 13.80!a ' _- ___ -- _ __ ' I SM ` ' 10 _____-_ _. � ' ' �__ � _becomes very dense � ;�� SS 100 17-50 MC=8-�°l� ' �� 3 ; : , __ _ _ �. , � � ii � � � q � ! �. � ( F � v/ 15 � � -- , : z � ��,� S5 100 ��7 � � -becomes rrsedium dense � : � -large cobbl�s, increasing gravel conteM , �_ ____ _ , � ; i J { ' � ' � 18.5 � 30 5 � — -�---_ -�.�_.� __-- -- - __ m y � ' .-Grayish-brown silty SAND w�h 9ravtl,�nse,wet to saturated{Til� J _1L_ � gM ' � - � � i � -rrrottled cabring (Cwatinued Ne�ci Page) ; x �_ � EaRh Solutions NW BORING NUMBER B-2 1805-136th Place N.E..Suite 201 PAGE 2 OF 2 ' ' '� Bellevue,Wasnington 98005 Telephone: 425�49-4704 Fax: 425-449-4711 IENT WJ Realty Acguisition Corp._ _ PROJEC7 NAME Mamott Resldence Inn _____ . ..OJECT NUMBER 3569 PROJECT LOCATION Renton,Washington w � � � — - - -- � — i. = F}-W 0}C H� N '= i W� i �m O ' 0 j� TESTS � a O i MATERIAL DESCRIPTION � ; Qz � mUz � c�7 � y � I 20 Gray�sh-0rown silty SAND with gravel,dense,wet to saturated(fi� SS 100 22(�)19 MC=9.50% ' ' (�nGnued) . _ -- — - — i i ' -mottled cobring SM � � 25 . _ — -- � i � ' � SS 100 �'33-24 MC=15.70% �57� � , _ . � �S --- -- _ __ _ _ _,_ _ 225 8oring terminated at 26.5 feet below existing grade Groundwater table encountered at 19.0 fee:du�ng drilling.2"PVC standp�pe insta►led ta 26.0 feeL �ower 10.0 feet sFotted.Boring backfiNed with bentonite chips and sand. , Bottom of Aole at 26.5 feet. i i i y^ ' z c^ a' v I � II n 2 m Cw Zy� O i 7�`; Earth Solutions NW BORING NUMBER B-3 � �805- 136th Place N.E., Suite 201 PAGE ' OF 2 , ' ' Bellevue,Washington 98005 i Telephone: 425�49�704 i Fax: 425�49-4711 ENT W.I._Realty Acquisition Co�,_, i,_, ___ PROJECT NAME Mamott Residence Inn ___ _ ______ . ..OJECT NUMBER 3569 PROJECT LOCATION Renton,Washingtcn _---� - — - - -------- _ DATE STARTED 10/6/14 COMP�ETEO 10/6114 GROUND ELEVATION 73 R HOLE SIZE DRILLING CONTRACTOR Boretec GROUND WATER IEVELS: DRILLING METHOD HSA _ AT T1ME OF DRILLING 35.0 ft!Elev 38.0 ft LOGGED BY DAM CHECKED BY HTYV AT END OF DRILLING — NOTES ,E�cposed Dirt/_T�oil�B�ambles� ___ ___ AFTER DRILLING — W o I = rW � �� CJ a r �� j �j Q TESTS v a O MATERIAL DESCRIPTION W" J ] N Q.J O � QZ I W I mOZ � (� � � 1 � i 0 Brown silty SAND, loose to medium dense,dry to damp SM �_0 72.0 __ ._._ _ ___----- _ ----- _— Tan sandy SILT with scattered gravel.very dense,dry ro damp ` , ___ ___,._------- - _ _--- ML ( � 15-25-50 i - G SS 100 �757 MC= 16.60% : F 4.0 69.D ___ -— ---_. ----- _. __---�_._, � Olive brown and gray sandy SILT,medium dense to very dense,moist 5 ', � -moit�ed coloring _ — — � SS 100 12-15-2D MC=2920% ( ; (35} � � . _ ! � -, --- - - _ _—- ; : � i � � 1� t 3-27-33 �=2a.0p% � ; �� , � ___ ___ _ ----- ( -becomes dense to very dense I �o � . . I � 1 • SS 100 �7�4�}24 MC=26.00% � -oxidat�n layering(rust color� � � '�� ML i + fl � � � � � � i $ 15 r -- � � � � t t-2&37 : � � • SS 100 (65? �=24.10% c� � ' � --=-- ` , � J { 4 � � t 1 { 1 _ ' + � s � I � W j 2 W 2� � 2�.0 5�� rCortt�nued Nexf Page1 � , � � — Eartn so��c�o�s tvw BORfNG NUMBER B-3 � �805- 136th Place N E-. Sude 201 PAGE 2 OF Z ' � ' ` Betlevue,Wasnington 98005 Telephone: 42 5-4a9-4704 Fax: 425-449-4711 JENT UVJ Rea'ty Acquisition Corp_ _ _ _ PROJECT HAME Ma_rriott Residence Irr tOJECT NUMSER 3569 PROJECT LOCATiON Rerton,Washmgton � i ' w � _ � �W � j �� a� O ; m p> , TESTS N �O MATERIAL DESCRIPTION � az W c�z � c9 � � 20 ' Gray sandy SILT,tlense to very dense, moist a SS 100 12-20-25 tiqC=26.90% ' (a�) ; - -- _ ..,_. ' t � ML C i � � � i 25 ��_- __.__ _�__ _ _ - � SS 100 ( 42-50 MC= t2 00% — �*.:, z5_s __ _ � _ __ 4�.5 G�ay poorfy graded SANO+�+ith sitt,very dense,moist ` ----___ ...__._ _ . it� �,� 'i� ilt '�; �;I 4� i! 30 I'' .SS 100 50l3" MC=2.60°� -increased gravel content ( SP- � SM ik� ;+: 35 ;, ;� __— -- ---- , � MC= 12 00% `�` -becomes wet to saturated �i� ' SS 100 22-50l5" �': � t, Fines=8.90% �� 4#f p i�� :J ��f N �E� � r Z $ � !S a ii � ,�s � :� '" 40 � �— _ -__ _.._ ------- - � �SS 100 2t 50/4" !WC= 14 00°� ��; -��Y dense —� — - — 41.0 �p , Boring terminated at 41.0 feet bebw existir�g grade.Groundvrater table m encauntered at 35.0 feet below existing grade.Boring back.fiHed with � bentonite chips. w Bottom of hole ai 41.0 feet. z , l Earth Sotutions NW BORING NUMBER B-4 � ?805- 136th Place N.E,Suite 201 ` ' ' '- Bellevue,Washington 98005 PAGE 1 OF 2 TslepAone. 425-449-4704 Fax: 425�49�711 ENT W.I Rea,ty Acquisitan_Co� _____ PROJECT NAME Marriott Residence Inn _ �JECT NUMBER 3569 _ PROJECT LOCATION Renton,Washington DATE STARTED 10/6l14 COMPLETEO 10/6/14 GROUND ELEVATION 70 ft HOIE SIZE . _ DRILUNG CONTRACTOR Boretec GROUNO WATER LEVELS: DRiLLJNG METHOD HSA -AT TiME OF DRILUNG 27.51t 1 Ebv 42 5 ft LOGGED BY DAM CHECKED BY HTW AT END OF DRILLING - NOTES Exposed Topsoil(Brambles) i_ _ __, AFTER ORILUNG — _ _ w � a} ° = F-� � H� � V 2 a� ' w°o w �Z"' TESTS v a O MATERIAL DESCRtPTION �� > � �j pv � QZ W mOZ I � �aJ � � � � 0 Brown silty SAND with gravel. bose to medium de�se,moist SM � � o s9 0 — ,.._. - - - ---__ �- Tan sandy SILT,very dense,dry to damp ii ( SS 100 7-14-5014" MC= 11.70% ! ._L..___ ... . ._..._-__. _ ML � : ` S ; SS 100 50 MC= 12.60% j 70 _ 630 -- - - ---- - _ __ . - Gray SILT, medium dense to very dense,moist ( SS 100 �-21-13 MC=28.2095 ! i ; (34) Fines=91.60% � ` --� ---�-� - - � � �Q ; ; _SS 100 5013" MC= 14.50°k - � + � � � i � i � i � l � ! �s.o s�c � � E Gray poorly graCed SAND w�th siR and gravef,dense,moist �`, � � '�: � 15 ;I': � _. -- - - ;'. � SS 100 18-2428 �=10.2096 �(j $ (52) r � -r-- — -- _ -- SP- SIM � i�� ,i i;; I ` -increased gravel content � ��, � I '. W �� _ � 2 (Con6nued NeXiPage) � ; � i / Earth Solutions NW BORING NUMBER B-4 '�805-136th Place N.E,Suite 20t PAGE 2 OF 2 � ' Believue,Washington 98005 Te+epho ne: 425�49�7Ua Fax: 425�d45-d711 ENT W.I. Reaity Acquisition Corp. _ PROJECT NAME Marriott ResidenCe Inn DJECT NUMBER 3569 PROJECT LOCATION Rerton.Washington ,_, W � a o _ ; �W I � �� v_ a� I J� ( j O�Q TESTS � a O MATERIAL DESCRIPTION o-- ' a� I o mo> �n �J aZ W V? � (7 N � 20 Gray poor�y graded SAND with sik and gravel,�nse,mast(continued) � SS 100 i 16�4�� MC=19.00% -becomes wet -a-- _�-- - _ - ---- ' ' 1 t i�{ F .` � .G J . . . . . j `� - _ __._�_._.' ___."a..' 1 4 7: ( � i`' ss �o0 2a61�3" Mc=�.�o�o � �1; � __ -- �� - - — +;i ,`; � ' - SP- i'; SM -�comes saturated �:� �:, I:# ,:; � -T-_ -- -- j F �X;f SS 100 � 30.50 MC=9.90% �� i � ;i ii; i � i '. i;` 35 '�` — ---—_ _ _ 1_� __ _ i : I � j�,k SS 100 12-24 MC=22.7Q°� ' �o aa o �., 50/5" _�+'' — --- — _ --- — ---- � ' '� �_ gM ; I �5 Brown silry fine SAND, very�nse,wei to saturated 33 s ^ - - ____ — ---__ __ -- - 8oring terminated at 36 5 teet below ezisbng grade.Groundwater table F encoun2ered at 27-5 feet during drill�ng_Boring backfclled with ber►tonite � chips. � Bottom of hole at 36.5 feet. � � z � d I � � J � � , I _ m 6J I K W Z W (� I 2 I Earth Solutions NW BORING NUMBER B-5 ' 1805-136th Place N E , Suite 201 PAGE 1 OF 2 ' ' ' � Bellevue.Washington 98005 Telephone. 425�d9-4704 Fax 425-4d9-4711 ENT W i Realry Ac�uisition Corp ______ PROJECT NAME Marr�an Residence Inn . ..�JECT NUMBER 3569__ PROJECT LOCATtON Renton,Washington DATE 3TARTED 1018/14 COMPLETED 10J8l14 GROUND ELEVATION 38 ft HOLE SIZE DRILLING CONTRACTOR Boretec GR�UNO WATER LEVELS: DRILLING METHOO HSA Y AT T1ME OF ORILLING 20.0 ft/Elev 18 0 ft LOGGED BY HTW CHECKED BY HTYY AT END OF DRILLING — NOTES Gravel AFTER DRIWNG — w � a � ►�r-W � H� � U a� a j O m O j TESTS N Q�! MATERIAL DESCRIPTION � QZ W UZ i � (�j � � 0 j � Brown silty SAND wKh�ravel, loose to medium dense, mo�st SM ; I � ; ,.s _�__ _�s Gray poorty graded SAND witt�gravel.dense.damp _ __ ___ _ -- ` � � 15-16-30 � � SS 100 (46) AAC=4.90°k , i - __ __ _ SP I r, 5 - -- t��, I � �mes wet ` SS 100 19-25- MC= 11.7096 � -IgM seepage 50/5" -_ __- _ 65 31 5 I, �, , Tan SILT with sand,med�um dense,wet 4 : _. _. _ _ _ � SS 100 �2'�417 MC=23.3096 + � (31) Fines=74.1096 _ _ � 'j : � - � � ,. � � 10 � -- -- — — - - _ -mottbd cobring 5-1Q-15 ' � SS 100 �25� MC=26.20% i � � � �— _ __ _ I , ' i : i � � i , -increasing fine sand content � i 0 � 15 ` � — _-------- I ; � SS 100 �12-15 MC=29.2096 I ' i ' $ t2�� ' � � -'- - - - --- � I n j J i 1 �j f 1 _ m ' ' � = I � � 2� � i ' (conn��ea n►ext PaQe� � ? `� � carth Solutions NW BORING NUMBER B-5 � '805- 136M Place N.E.,Suite 201 PAGE 2 OF 2 ' ' Befkvue,Washmgton 98005 Telepho ne: 425�d49-4704 Fax: 425�49�711 ENT W I Realty AcQuisRan Co{p. __ _ ___ PROJECT NAME MaRiott Residence inn �..JJECT NUMBER 3569 `__. PROJECT LOCATtON Renton,Washington _ ___ W io �� > v�w U i � _c�� o� a� O m p> TESTS � �O� MATERIAL DESCRIPTION �z W c�z � � � u�i a 2 : ; Tan SILT wRh sand.medium dense,wet(ow#inyed) I � i SS 100 �a��18 MC=32.50% II _ _-- � I � � � I ML i � li , � � 25 , _ _ __ _ __ � • SS 100 31-50t2" MC=15.40°h { i i 25 5 �2 s - —_ -- - — ---- -- — — -- I' ` — - - - ---- - - gp �o Gray poorly g�aGed SAND with gravel, very dense,saturated �Z o Boring;erminated at 26.0 feet below ex"�sting grade. Groundwater seepage encountered at 5.5 feet and groundwater Wble encountered at 20 0 feet dunng dnlling. Boring backfilled with bentonite Bottom of hale at 26.0 feet. . � � � � � a' � �5 � i � x m � z W _ W � � i - � li EaRh Solutrons NW TEST PtT NUMBER TP-1 `Bd5-136th Place N.E., Suite 201 ' � ' Bellevue,Washington 98005 PAGE 1 OF 1 T ele p h o n e: 4 2 5-a4 9�7 p4 Fax: 425�l49-471 t ENT YJ I Reairy Acquisftion Corp. __ _____ PROJECT NAME Mamott_Residence In_n �JECT HUMBER 3569 PROJECT LOCATION Renton,Washington _ -- _ —— DATE STARTED 10/2/14 COMPLETED 10l2/14 GROUND ELEVATION 46 ft TE3T PIT SIZE EXCAVATION CONTRACTOR NW Excavaiing GROUND WATER LEVELS: EXCAVATION METHOD AT T1ME OF EXCAVATION — L0C3GEd BY H7'W CHECKED BY HTW AT END OF EXCAVATION — NaTE3 Brambles AFTER EXCAVATION — w a _ � rw � _ a� � W°D ' TESTS V a O MATERIAI DESCRIPTION Q V � �Z ( ? �J Q I � � ' K Dark brown silty SAND with gravel. medium dense, damp(Fill) � SM 20 4ao -- -- -- —----- __. _ MC=2.90% Grdy poorly graded SAND, loose to medium dense. damp Fines=D.50°� � (USOA Classificat�on: SANDJ �� i � `, � ; ; 5 �=2�0� � gp � -medium dense ' ,'. -opde staining ' -moderafe cobbles AAC=3.10°� � , ! i �i s s s�.s I - -- ---- _— ------- - -- - Test pit terminated at 8.5 feet bebw exisGng gratle.No groundwater entountered during excavation. Bottom of test pk at 8.5 feet. 3 ti � t^ � i � G C7 s � I I ( i i m ' J � W Z W � I�� I I Earth Sol�tions NW TEST PIT NUMBER TP-2 � '805-136th PIaCe N.E.. Suite 201 PAGE 1 OF 1 ' � Betievue,Washington 98�5 Telephone: 425-449�70a Fax: 425-449-4711 IENT W I Reatty Acquisdion Corp. PROJECT NAME Nlarriatt Residence Inn OJECT NUMBER 3569 PROJECT LOCATION Renton.Washington _— ---- ----- — -- DATE STARTED 10/2/14 COMPLETED 10�2/14 GROUNO ELEVATION 38 ft TEST P1T SIZE EXCAVATIpN CONTRACTOR _NW Excavating___ __ GROUND WATER LEVELS: EXCAVATION METHOD AT 11ME OF EXCAVATION — _____�___ LOGGED BY HTW CHECKED BY HTW AT END OP EXCAVATION — __ _ _ NOTES Gravel AFTER EXCAVATI�N — __ _ w � a � x �W i ui =c� ~a� �� i TESTS V a p MATERIAL DESCRIPTION O Jj wv .�Z � � � i Q I � 0 ;�x�.` Dark brown silty SAN�with gravel,bose.moist(Filq SM -rrtetal pipe 45 355 ----- -_- -- ---------- - _ ___ ---- __ - Dark brrnvn poorly graded SAND, loose,damp(Fill} MC=9.f�°,b SP- SM >} 4.5 _33 5 5 tan SfIT,medium dense,mast MC=79.70% ML E ; 8.0 ---- -- --_ _ 32.0 Olive gray fine sandy SILT,rriedium dense,moist to wet Ml � If MC=30_80% � ` ' + ' 29.0 Y a h_9:� — - -----—_____ _ __.. _�_ __ , _ —. _ Test pit term�ated at 9.0 feet below existing grade. No groundwater encou�tered du�ing exCavBtiOft. Bottom oi test pit at 9.0 feet. . � c4i � � � c� °� � M m � W Z � ' ' � , ; I .1 Earth Solutions NW TEST PIT NUMBER TP-3 � 1805-136th Place N.E.,Suite 201 ' ' ' ' Belkv�,Washington 98005 PAGE t OF t Telep hone: 425-449-4704 Fex: 425-449-47 t 1 ENT Vb'I Realry Acquisition Corp_ __ _ _ PROJECT NAME Mamott Res�dence Inn OJECT NUMBER 3569 PROJECT LOCATION Renion,Washington DATE STARTED 10/2/14 COMPLETED 10%2�'4 GROUND ELEVATION 43 ft TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVEIS: EXCAVATiON METH�D AT T1ME OF EXCAVATION — IOGGED BY HTW CHECKED BY HT1N AT END OF EXCAVATION — NOTES Light_Brambles _ ___ _ _ AFTER EXCAVATION -_ � w � S }W cn i v I �� _ a= . �� TESTS � 'a�� MATERIAL DESCRIPTION �` �. �Z � ��J( � � N I � � ;T t,�` Dark brown sifty SAND with gravel, medium dense,dry to damp(Fili) SM 1.5 ,1 5 _ - -- _ ----—-— Brown silry SAND, loose to medium dense,damp MC=6.40% -becomes tan, medlum dense � : -weakly cemented ia 5 � _ y ; � • MC= 13J0% � ! -mottled cotonng Fines=49 20°�6 jUSDA Ciassification� LOAM] ' eo sso Test pit tertnmated at 8.0 feet below existing grade. No groundwater ent�untered during excavation Bottom of test pit at B.0 feet. f � H^3 V i � � V �J J _ ms II W 2 i W I C� 1 �� — —� Earth Solutions NW TEST PIT NUMBER TP-4 � 1 BOS- 136th Place N E.,Suite 201 PAGE � OF 1 I' ' ' Bellewe,Washingtan 98005 I Telephone: 425-449�+4704 Faac: 425-449�1717 ENT W I Reatty Acquisition Corp. ___�_ PROJECT NAME Marriott R85iCenCe Inn JJECT NUMBER 3569_ J PROJECT LOCATION Rento�.Weshington _ OATE STARTED '0/2r 14 COMPLETED 101?114 � GROUND ELEVATION 66 fl TEST PIT SIZE EXCAVATION CONTRACTOR NW ExC2vating GROUND WATER LEVELS: EXCAVATION METHOD AT 11ME OF EXCAVATION -- LOGCsED BY HTW CHECKED BY HTW AT END OF EXCAVATtON — NOTES Dep__th of To�so�8 Sod 6" grass____ _ _ __ AFTER EXCAVATION — � w = ia� v_ �-w �? _ w� � J� TESTS N Q O MATERIAL DESCRIPTION o a� � I. Q z � � c� 0 � S �o s TOPSOII to 6" 65 5 — — � -- _ __ __ _ __ __ _--- Gray si�ry SAND with gravel,dense,damp -moderately cemented MC=7.90% F ' SM I , 5 ' , -increas+ng sand conteM f ( k � 55 595 , v_.._ _ �_.— — __ � Gray poor!y graded SAND with sift,medium�nse to dense,damp � nnc=s.�o°� SP ; � snn ' ss s�s Test p+t terminated at 8.5 faet below existing grade. No groundwater encountered during excavat+on. Battom of test pit at 8.5 feet. i � .r :� � � z ^ � � 1, � J I 2 a.` ¢ ¢ w Z w , �� arth S�iutions NW TEST PIT NUMBER TP-5 'Sf15- 136th Piace N E..Suite 201 PAGE t OF 1 ' ' ' Be4levue,Washington 98005 Telephone: 425-449�1704 Fax. 425�49-�711 -''ENT W`I Real[y Auyu,isRiOn.Corp. _ _ ___. PROJECT NAME Marriop Residence Inn OJECT NUXIBER 3569 __ PROJECT IOCATtON Rentar,Washit►�ton __�_____ DATE STARTED 10t2114 COMP�ETED 10l2/t4 GROUNO EI.EVATiOtV 68 ft B �TEST PIT StZE EXCAVATIflN CONTRACTOR NW Excavating __ _ GROUNO WATER LEVEIS: EXCAVATtOH METHOD AT TfME OF EXCAVATIO#1 — LOGGED BY HTW CHECKEO BY HTW AT END OF EXCAVATION — NOTES _De�th_of 7opsoil_�Sod 6":li�hi brambles______ ._- -_.__ ____ AFT`ER EXCAVA710N -_ -----_ � � }� U S �� ' ~°Q TESTS � �J, MATERIAL DESCRIPTION p a� aZ � � � 0 � TPS a 5 TOPSOIL to 6° 67_s __ , _ _ _.._� __ Tan sandy SILT,medium dense to t�nse,damp MC=$JO°/n ' pn� -becomes dense -moderate�y cemented 5 _ _ i ; ; MC=10.74°lo I ; k Fines=58.60% (USDA Classificallon: IOAMJ f i t 7-0 ._---- 61 D , _�_____ ____ _ __ Test pit terminated at 7 0 feet beiow exisiing grade.Na groundwater encountered durirx� excavat�on. Bottom of test pit ai 7 0 feei. Q � � � � i � � a t� � M J J W _ �Q � � W � � �, � Earth So{utions NW TEST PIT NUMBER TP-6 1805-136th Place N E.,Suite 201 PAGE i OF 1 ' ' Believue,Washmgton 98005 Telephone: 425-449-4704 Fax: 425�49�71 t ENT W J Realty Acqu�s�tion Corp PROJECT NAME Marriott Res�dence Inn _ �JECT NUMBER 3569 PROJECT tOCATiON Rerton,Washington _ -. —__ . __ - - DATE STARTED t0/2J14 COMPlE7ED 10f?J14 GROUND ELEVATION 55 ft _ _ TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavatirx� __ ___ _ GROUND WATER LEVELS' EXCAVATION METHOD AT TiME OF EXCAVATION - IOGGED BY MTW CHECKED BY HTW AT END OF EXCAVATtON - NOTES Brambles _ AFTER EXCAVATION `_____ w = y� � U w MATERIAL DESCRIPTION w� j a j TESTS � a O Q I QZ � �� 0 >'<'-' Dar1c brown sdty SAND wKh gravei,loose,moist{Fill) ,y:• SM �;� 1 5 53 5 - -_ _-__ __._ _ --- ---. _ ._ Tan poorty graded SAND with sitt and gravel, bose to medium dense,dry to damp MC=3.00% -oxide siainmg SP- �''! SM i ; S I ' ' 6 A ______ 49.0 � __. ... ___---- -- -- i t` Gray poorly grade SAND, medium dense. damp ',� t_ AAC=6 20°� SP �iJ MC= 10.�% '9-9 _ __- __ __ _ __.,_ _ __ -- — ___ __ Test pit tertninated at 9.0 feet below existing grede. No flroundwater encountered durinp excavaGon. Bottom of test pit at 9.0 feet. 0 c� � z � a c� a � I � Z S � i w I ii �"� I Appendix B Labo�atory Test Resuits ES-3569.01 Earth Solutions N1N,LLC ?� J` . . • • :� • :�� . -. - . - . . . .- - .-. � . � . �, �. " �i�l1l 1 If��!.��i =� . . �. _ l�111� i�lllllll IIIII� ., ■ill 1 ��Nli' �. Ni�'�1 ■IIIII I IIII 11 1 ■II�111��!�111� ■r111111��111111 :, 1 11 ��II�111��111��►1��1111111��111111� 1 II 11��1�111 ■ IIIII►1►��111111��1� 1111 , 11■ 11111 II�11 11111111iii'�IIII 1 ■�IIIIIII 11� NII I 1 �III 1�1 ►- IIIIII ■�IIIIII ., 1 ■IIIIII I 1 ■�III 11 � �.11111��1111111� 1 IIII I 1 ■ III 1�1■ Iii111��1111111 �� , 1 IIII � 1� I IIII ■ ' 1[III��lIIII I . 1��1l1l11 11��1111 ■ Ii1111��111111 , 1 �IIIIII�! III 111i�II111N>�III 111��111111 � 1 �IlIIIII, III11 ��Illllll' �III 11��1111111 , �IIIIIII��III 11 ��IIIIIII �IIII 11��111111 1 �IIIII��IIIIl11��11111111��111111■ I1111■ , �i1111H��III1111r IIIIIII ■II IIII■ � IIII■ �IIIII� IIII■ IIIIII IIIII ■�IIIt111■ , 1 �IIIII I Il ■ IIIIII �I IIIII ��IIi1111 1 �IIIII 1 II#11��► III 11� IIIIIII , ��1111��11111 �IIIII��I! t11111 ,, . , , . � ,. . . : . - ._ ._ - .- - .- _ . . . - . . . � , . � � � � � .� ��. ��r�■� . , . . . . . �� ■� .- - . - _ . . �� ..� . � . , _ � � � i � -� � � � -_ � � � : � � �-� , Eartn Solutior.s NW GRAIN SIZE DISTRIBUTION 1805-136th Piace N.E.,Suite 201 Believue,WA 98005 Telephone: 42�284-3300 ^''�NT W.1. Realty Acquistion Corp _ PROJECT NAME Martiott Re.►idertoe Inn _ �_____ _�, _ I.IECT MUMBER ES-3569 PROJECT LOCATION Renton__ ___ __ _. _ —_.- __ - - __ _ . __ - --- U.S.SIEVE OPENING IN INCHES I U.S.S�EVE NUMBERS I HYDRpMETER 6 4 3 2 1 1 t2 3 6 810 /4 t 6 20 30 10 50 60 100 140 Z00 100 „� - � � ; i � i ; i g5 -- ' � ,; _ __ �_. 90 - - 85 8(Y - __ T5 � � 70 ---- -- � - � 65 - _ C� � _ � � '1 >- 55 m � w gp z � 1- 45 z w U � � W a 35 � - � 30 25 — ,� 20 15 -- ( �, 10 - -- 5 - I 0 ' 100 10 1 0.1 0.01 0.001 GRAIN SiZE IN MIIUMETERS � GRAVEL ` SAND SILT OR CLAY � j COBBLES �a� �e ��—�ium_t� _ j L Specimen Identification Classification ~ LL PL PI Cc Cu a �� B-1 2,5ft. Brown Silty SAND, SM _ � � B-3 35.Oft. Gray Poorty G�aded SAND with Sift and Gravel,SP�M 0.85 8.30 $ � B�d 7.5ft. Gray SIIT, ML _ 3 � B� 7.5ft. Tan SILT with Sand, Mt � ---- ---- -- -- - - -L � Specimen Identificatian D100 D60 D30 D10 °�Gravel %Sand , 9�6.Silt °�Clay_ � � B-1 - -- -2.5f�. 19 0.352 0.181 5.8 80.2 14.0 `_ i —n_ _ _ _-- _ --- B� 35.Qft. 37.5 0.715 ; 0.229 0.086 22.5 68•6 8•9 � o B� � �7.5ft. 4.75 - 0.0 8.4 .---_91.6 Z � B�5 7.5ft. 9.5 - — 1.3 24.6 74.1 `_ � - -- � � Appendix C Aerial Photographs ES-3569.01 Earth Solutions NW,LLC � �� . � �. =.- ..,,. ,� _ � � � _ . . :�' =� - ��- - : ; -- �� . _� , � , � � '4 �� ` _ �.� �`� �� ,' '�•- •` *�''�` �.w r �..� � :, � _ �:� � . `� : $ �� s�� `` � � {- , - a - �_ -` �t`� ' �t � ..`�- {�� : -- t . � `'�.��`g` �4� �ik$4-��9s�F � _ ' �z� �..- _ �S �x � ��' � _ . �-�` " �y °#�.- ` � �� _ ,a� t £��, � ,�+ �� . <�. y _ _ , �- � +``. �t":� "� a� �, � � `�F ��'�� i��`�+�`�J �. �� Yk �� +� � �s ��y�� <�� . f_ z : : � � _ _ � �:� �- �' �a*''F``a' �r- •. #- - -- -. t �� `r �, $� �� r �� } � �� .�3 _ � � , � � . �� ` � �` ��+�� j�,� �„ � �_. -�� - . -.a � ��,F. .s� -''..'�_Li_ _ _ �. >€ . .�'� .� $ a� �a �. ;-; '� � � ��- � � - ' _� - ��. _:}'` -i �� +� f�� _ � � � �-- -t " :�_ . � � �� .=,�� #�� G 3�� : :� � � ��- � .�i � �.R �� : ��y ��nr .� � ��w�.-'� _'� .� �`� .'� '�, -*- � � � � � a' � � ;. �-� - �' � {'�'�� ' ' �� `�. � _ � � � { 4. 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'"4 { � -1..-�` .-.. ♦ � ,� t � a t' �'� 'p �� y � ' �.� _ :`s �' 1 . _ti�� ' '. _ . �� '. +� � *1 � t� ! �� V� "� j��,' '-� ��' '_ t�� ' �� ' *R�`- �t�, t ' `_�' * - .� � ` � �' ' ` � ` • / I'� ��' a: J ,'Q� � � � / � •� �� i, . � , . r � �� - � r . � �, � . �� .a� I I NORTH �, � � � � � ,��; F�� :�� Aerial Photograph 1970 Marriott Residence Inn i Renton, Washington I� Drwn. GLS Date 04l20/2015 Proj. No. 3569.01 � Checked HTW Date April 2015 Plate C7 j `�'� � F� �a � } � �_ � � ;� , � � i� �� z ,,� _� =�� /� � ;�� ` �:_ � � � _ � �" '� :'� . - ,. , � _ < � � � :,.,, : ;}� `�'> �1�,, _ � � ik ��.L {� � � � � _� j ` - , � } -�y �� # '�.� � �a �� -�_� ;� �; -. $,q �.�`� � , ;_ 4 r. �_ > # — '.k.:$� §�`S. - . ��. - � �c, � $ �� •��.. �` �� d` _ . ' " � �J...��` ��P , _� x. yyy""" * . .. .� -�� _ �� '',� '3' �..-. #tr.- f_�. �.- 7 � x� . �. � �� 3•� � '. 3��¢ � 6�� $.�: �'S .:. S. � �,. r` F �. - - _ � � � i ' # �` �.�'�-. * � �. E } .. � � # s5 < , 3 a� � {' � � . ._ s y, e ._ , . � � . � - .. ..F '. �. g . " € '�- F .... ' - . _ -: �.: , _ � ..� .._ � �..t j ' " �-� ..8.... � � -. ... �s ° i •. � �}�, ,�.: _� � �. , . �� . S_ s' �[S . e "f ' � � � �� ' ,, �M1 � �` � ' � � � M� . � � „ :_ - 4�i � ��. _ ` �. � :�, NORTH � � x � � � �i � -�+i.. I Aerial Photo��ra h 1970 �� 9 P Marriott Residence Inn Renton, Washington ' Drwn. GLS Date 04/20/2014 Proj. No. 3569.01 I�, Checked HTW Date April 2015 Plate C8 ;�,�`; ! Appendix D Stope-W Computer Output ES-3569.01 Eanr S� .,t�^s N�.'J L_� i � `_y _1.._ 125 ' ES-3569.01 Marriott Residence Inn Existing Condition �oo ��- Static Condition Proposed Retaining Wall � B-3 � N=75 75 � 25 C �Q ° Proposed Hotel Building Drive Lane / � � Walkway �� Dense t Very Dense MUSM w �'" a�; �. _ + :. 50 ' ��„ . i B-5 _�.�. �. ,a _.�`�''1 SOf5., - Nledium Dense ! �°�� a�,� 3� Dense SM z� 25 �o Very C►ense Sand 0 0 25 50 75 100 115 15U 175 200 225 Distance rl_ '1- 125 ES-3569.01 Marriott Residence Inn ; Existing Condition �� Static Condition 2�� Proposed Retaining Wall M .�' c; � ' N-s�� C 75 � � � � ; ""� � Proposed Hotel Building Drive Lane ! � � � _ �a yWalkway 6� Dens�1 Very Qense MUSM � �� tu � 50 ! �•° � B-5 ��" �,�,"'°� �as., �r „ Medium Dense I �� f rJQ�J 3� Dense SM as 25 z' Very C►ense Sand aa or�� 0 D 25 50 75 100 125 150 175 200 2.25 Distance 4J2CV2015 t�c�snng�ono�;�oru Existing Conditions Reoort generated using Gea5tvdio�OD7,version 7.21.topyright'��49i-20i3 GEG-SLO?E intemationa:Lxo. File Information Title: Marriatt Residence Inn Created By: Henry Wright Revision Number: 11 Last Edited By: Henry Wright Date: 4/2�j2015 Time: 2:08:14 PM File Name; Existing Candition, Static.gsz Directory: C:\Users\henry.wright��ocuments�SlopeW\3569.01\ �ast Solved Date: 4J20/2415 Last Solved Time: 2:48:17 PM Project Settings �ength{�} Units: feet Time(tj Units: Seconds � Force(F) Units: Ibf i PresSure(p) Units: psf I!� Strength Units: psf �, Unit Weight of Water: 62.4 pcf � View: 2D I Analysis Settings Existing Conditions Kind: SL�PEjW Method: Morgensterr-Price Settings Side Function Interslice force functior� optifln: F�al{-S�ne PWP Canditions Source: (none;� Slip Surface Direction of movement: Ri�;7, t� �e`- Use Passive Mode: No Slip Surface Optian: Entry �rd Lx t Critical slip surfaces saved: 1 Optimize Critical Slip Surface Locatia�: 'v V Tension Crack Tension Crack Option: (none} FOS Distribution FOS Calculation Option: Constant Advanced � ��,; ' hle��l�C:+Usersrt�erry.v�rigtrJDocumarts/SlooeV`�,�569.O��exist�ng°k2t)cond�tion'�o2Qstai;c�m1 1J4 41'1tY1U1 S �xi�u�y t,u U��u�. Number of Slices: 30 Optimization Tolerance: 0.01 Minimum Slip Surface Depth: 0.1 ft Optimization Maximum Iterations: 2000 � Optimization Convergence Tolerante: 1e-007 Starting Optimization Points: 8 Ending Optimization Points: 16 Complete Passes per Insertion: 1 Driving Side Maximum Convex Angle: 5 ° Resisting Side Maximum Convex Angle: 1 ' Materials Medium Dense ML/SM Model: Mohr-Coulomb Unit Weight: 125 pcf Cohesion: 0 psf Phi: 34 ° Phi-B: 0 ° Dense ML/SM Model: Mohr-Coulomb Unit Weight: 125 pcf Cohesion: 500 psf Phi: 32 ° Phi-B: 0 ° Very Dense Sand Model: Mohr-Coulomb Unit Weight: 120 pcf Cohesion: 0 psf , Phi: 38 ° Phi-B: 0 ° Slip Surface Entry and Exit Left Projection: Range Left-Zone left Coordinate: (7.81225, 40.3662j ft left-Zone Right Coordinate: (110.80393, 66.55993y ft Left-Zone Increment:4 Right Projection: Range Right-Zone Left Coordinate: (164.33071, 80)ft Right-Zone Right Coordinate: (225, 80) ft Right-Zone Increment: 4 Radius Increments: 4 Slip Surface Limits i�� file:///C:NSersJt�enry.wright^Joc:ments!S'ope'dJl"�569 0liexis!�ng°1o20condition.°�20stadc htrnl ?J4 4120V2015 twsung c,anoivans left Coordinate: (0, 40� ft Right Coordinate: (225, 80) ft smic Loads Horz Seismic Load: 0 Regions ._ ____-- --__ � --- -- - -- ___ -�_ _-� � ____ _ Material Points � Area (ftZ) Region 1 Medium Dense ML/SM 2,11,13,12 838 Region 2 Very Dense Sand I,12,13,11,3,4,5,10,9 9884 L Region 3 Dense ML/SM 5,6,7,8,10 3272 Poi nts --- _--� X {ft) j Y (ftj �--Point 1---�-0 - 0 � Point 2 � 0 ' 40 f-- � Point 3 85 44 Point 4 90 45 Point S 95 49 Point 6 122 79 Point 7 124 80 Point 8 225 80 � Point 9 225 0 � F Point 10 225 54 Point 11 64 43 Point 12 0 17 Point 13 30 26 � Critical Slip Surfaces , -- ---- - - ------ ------- -- � Slip Surf ca e FOS Center (ft) � Radius {ft) Entry (ft) Exit (ft) � 1 52 2.041 (67.663, 187.583) 144.633 (164.331, 80} (63.9505, 42.9977) Slices of Slip Surface: 52 Slip i X (ft) Y (ft) PWP Base Normal Frictional Cohesive Surface {psf) Stress (ps� Strength (psf) Strength {psfl � 1 52 63.971855 42.997135 0 0.1946729 0.13130853 0 2 52 63.99659 42.996505 0 0.41191705 0.32182487 0 ' 3 52 65.75 42.97327 0 ! 13.414827 10.480812 0 4 52 69.25 42.96932 0 34.332216 26.823267 0 5 52 72.75 43.050115 0 45.026408 35.178485 0 6 52 76.25 43.215795 0 45.351273 35.432298 0 7 52 79.75 43.46665 0 35.267609 27.554076 0 8 52 83.25 43.803135 0 14.848718 11.60109 0 fileJJlC:NSerSThenrywrighUDocument5/SlopeW,'3569.01lpcisting°roZOcon�tim.%ZOstatic.hlml ' - 3l4 �%'n yl(Y1015 F�osbng C;ondbor�s 9 52 87.5 44.33906 0 20.294327 ' 15.855666 0 10 52 92.5 45.12112 0 220.84885 172.54603 ' 0 11 52 96.607295 45.885285 0 574.89096 449.15405 0 12 52 99.821895 46.580175 0 912.82225 713.1749 0 13 52 103.0365 I 47.352195 0 1232.8948 963.24296 0 14 52 ; 106.2511 48.20262 0 1534.517 1198.8961 0 ;-- -- 15 52 ; 109.4657 � 49.132845 0 1817.5234 1420.0049 0 16 52 � 112.89415 50.217855 0 2089.2513 1305.5091 5Q0 ; 17 52 116.5365 51.471445 0 2361.1931 1475.4372 S00 � 18 52 120.17885 52.83514 0 2611.5364 1631.8691 500 � 19 52 123 53.959035 0 2726.6407 1703.7942 S00 � 20 52 125.68045 ' S5.109115 0 2621.0693 1637.8259 500 � 21 52 ! 129.04135 56.632715 0 2417.2912 1510.4912 500 � 22 52 132.40225 58.2616 � 2208.6991 1380.1484 500 23 52 � 135.76315 59.99981 0 1945.1182 1246.68$2 � 500 .. -- 24 52 � 139.124Q5 61.85188 0 1776.0587 j 1109.8046 S00 25 52 I 142.48�95 b3.822925 0 1550.C839 ' 968.97482 500 26 52 � 145.8458 '. 65.91874 0 1317.870,-_-7 -� 823.497 S00 27 52 149.20665 68.1459 0 1076.1804 672.47215 500 28 52 152.56i55 70.51151 0 823.82862 514.78526 500 -� - 29 52 155.92845 73.02539 0 558.83105 ! 349.1964 _�500 30 52 159.28935 75.696295 0 278.74948 174.18201 500 31 52 162.65025 ' 78.53522 ' 0 -19.026288 -11.88�94d 500 �7 ) �1e:liJ:.':^Jsersfienry wng�'�x�e�':s'S�pe�'J135E9.0''existinq°h20condl on,°�o2xtat:c html M4 ' \ 125 ES-3569.01 Marriott Residence Inn Existing Condition �� - Seismic Condition 1 I26 Nroposed Retaining Wall • �� B-3 , , f � -�- � �� 75 _ � � � � � � � Proposed Hotel Building Drive Lane / � i £� � ' ° -00 Dense / Ve Dense MUSM '" ' ry � WalkwaY � ' � ss > , � 4� W 50 � �„ B-5 ,_,-_�_ "` 50I5" � 50/4" �5„ Medium Dense / 3� Dense SM 25 25 ?� Very Dense Sand 0 U 25 5U /ti 100 12�i 15U 1I5 200 225 Distance 4/2�2015 u�sury i,uRsuuc Existi ng Cond itions Report generated using GeoStudlo 2007,version 7.21.Copyright�1991-2013 GEO-SLOPE International LId. File Information Title: Marriott Residence Inn Created By: Henry Wright Revision Number: 14 Last Edited By: Henry Wright Date: 4/20/2015 Time: 2:13:43 PM File Name: Existing Condition, Seismic.gsz Directo�y: C:\Users\henry.wright\Documents\SlopeW\3569.01\ Last Solved Date: 4/20/2015 Last Solved Time: 2:13-46 PM Project Settings Length(L) Units: feet Time(t) Units: Seconds Force(F) Units: Ibf � Pressure(p) Units: psf Strength Units: psf Unit Weight of Water: 62.4 pcf View: 2D j Analysis Settings �I Existing Conditions Kind: SLOPE/W Method: Morgenstern-Price Settings � Side Function Interslice force function option: Half-Sine PWP Conditions Source: (none) � Slip Surface Direction of movement: Right to Left Use Passive Mode: No Slip Surface Option: Entry and Exit Critical slip surfaces saved: 1 Optimize Critical Slip Surface Location: No Tension Crack • Tension Crack Option: (none) FOS Distribution FOS Calculation Option: Constant Advanced i�3 file:N/C:Nsefsfie�ry.wrighWocumentslSlope�lN�'35@9 01/exis6ng°r620condition°r620se+smic.tMm1 V4 4I202015 rwsung�onanons Number of Slices: 30 Optimization Tolerance: 0.01 Minimum Slip Surface Depth: 0.1 ft Optimization Maximum Iterations: 2000 Optimization Convergence Tolerante: 1e-007 Starting Optimization Points: 8 Ending Optimization Points: 16 Complete Passes per Insertion: 1 Driving Side Maximum Convex Angle: 5 " Resisting Side Maximum Convex Angle: 1 ° Materials Medium Dense ML/SM Model: Mohr-Coulomb Unii Weight: 125 pcf Cohesion: 0 psf Phi: 34° Phi-B: 0 ° Dense ML/SM Model: Mohr-Coulomb Unit Weight: 125 pcf Cohesion: 550 psf Phi: 32 ° Phi-B: 0 ° Very Dense Sand Madel: Mohr-Caulomb Unit Weight: 120 pcf Cohesion: 0 psf Phi: 38 ° Phi-B: 0 ° I Slip Surface Entry and Exit left Projection: Range ', left-Zone Left Coordinate: f 7.81225, 40.3662) h ' Left-Zone Right Coordinate: {110.80393, 66.55993) ft left-Zone Increment: 4 ! Right Projection: Range Right-Zone Le#t Coordinate: (164.33071, 80j ft Right-Zone Right Coordinate: �225, 80)ft Rigt�t-2one Increment: 4 I Radius Increments: 4 Slip Surface Limits �I �� fi1e:11rC:Nsers�xy.wriyhW ocuments/SlopeWt3569.01/existing%20cor�Gon,%20seism�c.htrnl 2/4 ��5 CXISIIIy I,.URIIUUC left Coordinate: (0, 40) ft Right Coordinate: (225, 80) ft smic loads Horz Seismic Load: 0.3 Ignore seismic load in strength: No Regions -------- _ — _ - __----------�—___ _, � Material Points Area {ft2) � Region 1 Medium Dense MLJSM 2,11,13,12 838 � Region 2 Very Dense Sand 1,12,13,11,3,4,5,10,9 9884 Region 3 Dense ML/SM 5,6,7,8,10 3272 Points �- �--- - --X �ft�--,- Y �ft� � Point 1 0 0 Point 2 0 40 Point 3 85 44 Point 4 90 45 Point 5 95 49 Point 6 122 79 Point 7 124 80 Point 8 225 80 � Point 9 225 0 Point 10 225 54 Paint 11 64 43 Point 12 0 17 Paint 13 30 26 Critical Slip Surfaces j Slip Surface � FOS Center(ft) Radius (ftj � Entry(ft) Exit (ft) 1 27 i �1.226 (55.326, 210.952} 170.383 ; (164.331, 8QS (35.8814, 41.6819) Slices of Slip Surface: 27 S��p X (ftj Y(ft) � P�P Base�Normal Frictional� Cohesive Surface a (psf) St�ess (psfj Strength {psf) Strength (psf) 1 27 38.215935 41.446285 0 48.889664 32.976494 0 2 27 42.88502 41.039695 0 148.13149 99.91595 0 ! 3 27 a7.554105 40.76215 0 243.4557 i54.21294 0 4 27 52.22319 �0.61301 0 329.753 ! 222.4212 0 ' 5 27 56.892275 40.591945 0 399.44043 269.42597 0 6 27 b1.61341 40.701545 0 495.68308 387.27007 0 7 27 66.1 40.922745 0 523.61657 409.0941 0 fi1e:///C:JUsers/herry.wrig�tlDoamarrtsrSlopeVJ.ra569.01/exist�no°k20condt�on,%2()seismic ritml • 3�'4 /--�� 4120fZ015 :x�sury�,uu�uu4 8 27 70.3 41.2411 0 520.43051 4G6.60�88 ; 0 9 27 74.5 41.66424 0 480.09702 375.0929 0 10 27 78.7 42.19295 0 405.48629 316.80061 0 11 27 82.9 42.82823 0 304.08027 237.57355 0 12 27 87.5 43.653435 0 224.78098 175.b1815 0 13 27 92.5 44.693195 0 348.78787 272.50295 0 14 27 96.874095 45.72343 0 637.87348 498.36138 0 15 27 100.62229 46.71155 0 909.66796 710.7105 0 16 27 104.3705 47.791745 0 1132.3093 884.65697 0 17 27 108.1187 48.96586 0 1320.3711 1031.587 0 18 27 111.994 50.282465 0 1744.9784 1090.3835 550 19 27 115.9964 51.750935 0 1842.2186 1151.146 550 ! 20 27 119.9988 53.33471 0 1944.4381 1215.0198 550 � -- - ' 21 27 123 54.58864 0 1985.7017 1240.8041 550 22 27 126.2406 56.04717 0 1867.8914 1167.1881 550 23 27 130.7218 58.178665 0 1671.9785 1044.7682 550 24 27 135.203 60.473785 0 1484.4303 927.57503 550 25 27 139.6842 , 62.94015 0 1295.601 809.58138 S50 26 27 144.1654 65.58649 0 1095.6834 684.65895 550 27 27 148.64655 68.422845 0 874.09594 545.19577 55d 28 27 153.1277 71.460825 0 618.9221 386.74545 550 29 27 157.6089 74.713945 0 315.88898 197.38934 550 30 27 162.Q901 78.198055 ' 0 � -53.043401 -33.145195 550 �� fil eYlJC:Nsers/henry wr ic�,�L ocumentslSl opeV`�'J3569 01�ex isti nq°jo20ccndib on%205e+s m i�!�mi � N4 Repon Distribution ES-3569.01 EMAIL ONLY W.I. Realty Acquisition Corp. ' 13647 Montfort Drive Dallas, Texas 75240 , Attention: Ms. Cary Fisher E rr I i�rs NW L I a . So�t„ LC �� • 7.0 OTHER PERMITS I � /��' 7.0 OTHER PERMITS Other permits for this project include: • NPDES Construction Stormwater General Permit • Waterline Extension Permit from City of Renton • Side Sewer Permit from City of Renton • Clear and Grade Pe�m ; • Site Development Pe�m�t • Right-of-Way Use Permit • Building Permit • Shoring and Wall Per�nits .;�o� w& .�., I� 1 8.0 CSWPPP ANALYSIS AND DESIGN ;��:�� WAR #303557 Stormwater Poltution Preventian Plan For Marriott Residence Inn Prepared For Western internationa! 13647 Mantfort Drive DalFas. TX 7524Q Owner Developer Operator/Contractor Western International Western International EBCO General Corstractor. Ltd. 13647 Montfort Drive 13647 Mantfort Drive 305 West Giilis Avenue dallas. TX 75240 Dalias. TX 75240 Cameran. TX 76520 Project Site l.ocation 1200 Lake Washington Boulevard Nortt� Renton, Washington Certified Erosion and Sediment Contro! Lead Lewis Conklin Earth Salutions NV`J (425) 284-330{l CESCL No. EF8181596 SWPPP Prepared By �_�� Barghausen Consulting Engineers. Inc. 18215 - 72nd Avenue South �¢�Y �AC!�{,; Kent, WA 98a3� �`t�.t�„r,,�� S (425) 251-6222 �: :� . :� Ali Sadr, Senior Project Engineer J, ;, ti �' ,. �, SWPPP Preparation Date ;�, kf.2rs$� � April 21, 2015 f � ��s:s�iU��_ �� Revised February 22, 2016 Re��ised April 7, 2016 - Approximate Project Constructian Dates Start Date: June 2016 End Date� June 2017 I 15564.00S.dc; ��S: � Sformwater Pollutton Prevenfron Pian Contents 1.0 Introduction ................................................... . . .. ............_._. _.. ........ . .. . ._..._. ..._ ' 2.0 Site Description ...............................................................................................................3 2.1 Existing Conditions ...................�---...................--•---.......................-�---.._...............3 2.2 Proposed Construction Activities..........................................................................3 3.0 Construction Stormwater BMPs.............•--......................................................-�----.....,.....5 3.i The 14 BMP Elements .............................................................5 ............................ 3.1.1 Element#1 — Mark Clearing Limits..............•--------.-----.,...........................5 3.1.2 Element#2 — Establish Construction Access ..........................................5 3.1.3 Element#3— Control Flow Rates............................................................6 3.1.4 Elemen##4 — Install Sediment Controls...................................................6 3.1.5 Element#5— Stabilize Soils....................................................................7 3.1.6 Element#6— Protect Slopes...................................................................8 3.1.7 Element#7— Protect Drain Inlets............................................................8 3.1.8 Element#8— Stabilize Channels and Outlets..........................................9 3.1.9 Element#9— Control Pollutants..............................................................9 3.1.10 Element#10— Control Dewatering........................................................10 3.1.11 Element#11 — Maintain BMPs..............................................................11 3.1.12 Element#12 — Manage the Project .......................................................11 3.1.13 Element#13 — Construction S#ormwater Chemical Treatment ..............13 3.1.14 Element#14 — Construction Starmwater Filtration.................................19 3.2 Site Specific BMPs...................... ..........................-�-----�---................,...20 .............. 4.0 Construction Phasing and BMP Implementation............................................................21 5.0 Pollution Prevention Team.............................................................................................22 5.1 Roles and Respansibilities................................................•--.......,....,.................22 5.2 Team Members................•---..........................-�-�----..........................................._23 fi.0 Site Inspections and Monitaring.....................................................................................24 6.1 Site Inspection...................................................................................................24 6.1.1 Site Inspection Frequency.....................................................................24 6.1.2 Site Inspection Documentation..............................................................24 6.2 Stormwater Quality Monitoring...........................................................................25 6.2.1 Turbidity Sampling ................................................................................25 6.2.2 pH Sampling .........................................................................................26 7.0 Reporting and Recordkeeping.......................................................................................27 7.1 Recordkeeping...................................................................................................27 7.1.1 Site Log Book........................................................................................27 7.1.2 Records Retention ................................................................................27 7.1.3 Access to Plans and Records................................................................27 7.1.4 Updating the SWPPP..................................................................�..._.....27 7.2 Reporting...........................................................................................................28 7.2.1 Discharge Monitoring Reports...............................................................28 7.2.2 Notification of Noncompliance......................_...................._.._......._.....28 ii �sssa.00s.do� r 4,� i..- Stormwater Poltution Prevenfion Plan Appendix A Site Plans Appendix B Construction BMPs Appendix C Alternative BMPs Appendix D General Permit Appendix E Site Inspection Forms (and Site Log) Appendix F Engineering Calculations ill 15564.005.doc � t ly 1 � � Stormwater Po!lution Preveniron Plan 1 .0 Introduction This Stormwater Pollution Prevention Plan (SWPPP) has been prepared as part of the NPDES stormwater permit requirements for the Marriott Residence Inn project in Renton, Washington. The proposed site is located on the northeast corner of Lake Washington Boulevard North and N.E. Park Drive, Renton, Washington. Construction activities will include the addition of one bui(ding, asphalt parking lots, landscaping, utility work, including power, telephone, gas, cable television, water, sewer. and storm appurtenances with catch basin collection, pipe conveyance, stormwater quality, and flow cantrol facilities, etc. The purpose of this SWPPP is to describe the proposed construction activities and all temporary and permanent erasian and sediment contro! (TESC) measures, pollution prevention measures, inspectionlmonitoring activities, and recordkeeping that will be implemented during the proposed construction project. The objectives of the SWPPP are to: 1. Implement Best Management Practices (BMPs) to prevent erosion and sedimentation, and to identify, reduce, eliminate or prevent stormwater contamination and water pollution from construction activity. 2. Prevent violations of surface water quality, ground water quality, or sediment management standards. 3. Prevent, during the construction phase, adverse water quality impacts including impacts on beneficiaf uses of the receiving water by controlling peak flow rates and volumes of stormwater runaff at the Permittee's outfalls and downstream of the outfalls. This SWPPP was prepared using the Ecology SWPPP Temptate downloaded from #he Ecology website. This SWPPP was prepared based on the requifements set forth in the Construction Stormwater General Permit, Stormwater Managemenf Manua/for Western Washingion {SWMMWW 20Q5j. The report is divided into seven main sections with severai appendices that include sto�mwater related reference materials. The tapics presented in the each of the main sections are: • Section 1 - 1NTRODUCTION. This section provides a summary description of the project, and the organization of the SWPPP dacument. � Section 2 -SITE DESCRIPTION. This section provides a detailed description of the existing site conditions, proposed const�uc#ion activities. and calculated stoRnwater flow rates for existing conditions and post-construction conditions. • Section 3- CONSTRUCTlON BMPs. This section provides a detailed description of the BMPs to be implemented based on the 12 required elements of the SWPPP. 1 15564.005.doc �L'�� Stormwater Pollution Prevention Plan ■ Section 4— CONSTRUCTION PHASING AND BMP IMPLEMENTATION. This section provides a description of the timing of the BMP implementation in relation to the project schedule. ■ Section 5— POLLUTION PREVENTION TEAM. This section identifies the appropriate contact names (emergency and non-emergency), monitoring personnel, and the onsite temporary erosion and sedimentation contro{ inspector ■ Section 6— INSPECTION AND MONITORING. This section provides a description of the inspection and manitoring requirements such as the parameters of concern to be monitored, sample locations, sample frequencies, and sampling methods for all stormwater discharge locations from the site. ■ Section 7— RECORDKEEPING. This section describes the requirements for documentation of the BMP implementation, site inspections, monitoring results, and changes to the implementation of certain BMPs due to site factors experienced during construction. Supporting documentation and standard forms are provided in the following Appendices: Appendix A — Site Plans Appendix B — Construction BMPs Appendix C —Alternative BMPs Appendix D — General Permit Appendix E — Site Inspection Forms (and Site Log) ! Appendix F — Engineering Calculations I 2 15564.005.doc i 1�.,; Stormwater Pollution Preventron Plan 2.0 Site Description 2.1 Existing Conditions The total area of this two parcel site is approximately 2.89 acres and the site is located within a portion of the Southeast quarter of the Southwest quarter of Section 5 and of the Northeast quarter of the Northwest quarter of Section 8, Township 23 North, Range 5 East, Willamette ��teridian, City of Renton, King County, Washington. More particularly the site is located at the northeast corner of Lake Washington Boulevard North and N.E. Parlc Drive. Please see the Vicinity Map for an exact location of the site. Under existing conditions the majority of the site consists of forested land. There is also an area in the westem portion of the site consisting of gravel surface area of approximately 0.47-acre of impervious surface which serves as a parking lot for vehicles. The remainder of the site is moderate and steep slope till forest. A Puget Sound Energy power easement for transmission mains comprises most of the southern parcel on the site. 2.2 Proposed Construction Activities The area-specific flow control facility is the Peak Rate Runoff Flow Control Standard as delineated by the City of Renton Amendments to the 2009 King County Surface Water Design Manual. This is a peak rate runoff matching standard in which the 2-, 10-, and 100-year pre- developed peak runoff rates utilizing existing conditions are the release rates during the same 2- �0-, and 100-year respective storm events for the developed condition. The applicabte conveyance system capacity standard is the Modified Rational Methai as delineated in the 2009 King County Surface Water Design Manual utilizing a 100-year precipitation, a Manning's 'n' value of 0.014 in the pipes and an initial time of concentration of 6.3 minutes. This is a conservative methodology and usually creates pipes large in size than what would normally be required for a given storm event. The applicable land use-spec�c water quality requirement as determined per Section 1.2.8.1 of the City of Renton Amendments is the Enhanced Basic Water Quality Standard which is being met with the modular wetland system located downstream of the detention for this project. Please see the calculations in this report for additional information. In addition, oil control is not required and the Source Control BMPs for this site �nclude covering the trash enclosure and educating the owner about the proper use of pesticides and fertilizers as well as regular sweeping of the paricing lot. Construction activities will include site preparation, TESC installation, building construction, stormwater and utility appurtenance installation, and asphalt paving. The schedule and phasing of BMPs during construction is provided in Section 4.0. Stormwater runoff rates and volumes were calculated using the KCRTS hydrology model and the detention vault was sized by matching predeveloped peak rates to release rates for the 2-, 10- and 100-year events. 3 15564 005 do� �i�n '� Storm.water PolJution Prevent�on Plan The following summarizes details regarding site areas ■ Total site area: 2.89 acres , ■ Percent impervious area before construction: 16% '� ■ Percent impervious area after construction: 39°/o 'i ■ Disturbed area during construction: 3.0 acres 'I ■ Disturbed area that is characterized as impervious {i.e., access , roads, staging, parking): 0.5 acre � All stormwater flow calculations are provided in Appendix F. 4 15564 005 d��+� , �. �r / i.� i Stormwater Pollution Prevenfion Plan 3.0 Construction Stormwater BMPs 3.1 The 14 BMP Elements 3.1.1 Element #1 — Mark Clearing �imits To protect adjacent properties and to reduce the area of soil exposed to construction, the limits of construction will be clearly marked before land-disturbing activities begin. Areas that are to be presenred, as well as all sensitive areas and their buffers, shall be clearly delineated, both in the field and on the plans. The BMPs relevant to marlcing the clearing limits that will be applied for this project include: ■ High Visibility Plastic or Metal Fence (BMP C103) The clearing limits shall be as shown on the plans and all vegetation outside of the clearing limits preserved. Alternate BMPs for marking clearing limits are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the altemative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.2 Element #2 — Establish Construction Access Construction access or activities occurring on unpaved areas shall be minimized, yet where , necessary, access points shall be stabilized to minimize the tracking of sediment onto public roads. Street sweeping and street cleaning shall be employed to prevent sediment from entering state waters. All wash wastewater shall be controlled on site. The specific BMPs related to establishing construction access that will be used on this project include: i ■ The roads shall be swept daily should sediment collect on them. ■ Stabilized Construction Entrance (BMP C105) Alternate construction access BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the altemative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 5 15564.00S doc a j ��J Stormwater Pollution Prevention Plan 3.1.3 Element #3 — Control Flow Rates In order to protect the properties and waterways downstream of the project site, stormwater discharges from the site will be controlled by construction of a sediment trap combined with Baker tanks as one of the first items of construction. • Sediment Trap (BMP C240) Alternate flow control BMPs are included in Appendix C as a quick �eference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s)of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the altemative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, the project must comply with Minimum Requirement 7 (Ecology 2005). In general, discharge rates of stormwater from the site will be controlled where increases in impervious area or soil compaction during construction could lead to downstream e�osion, or where necessary to meet local agency stormwater discharge requi�ements (e.g., discharge to combined sewer systems). 3.1.4 Element #4 — Install Sediment Controls All stormwater runoff from disturbed areas shall pass through an appropriate sediment removal BMP before leaving the construction site or prior to being discharged to the downstream drainage course. The specific BMPs to be used for controlling sediment on this project include: • Silt Fence (BMP C233) • Sediment Trap (BMP C240) A silt fence shall be installed along the downstream perimeter of the proposed site. Alternate sediment controi BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the altemative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. In addition, sediment will be removed from paved areas in and adjacent to construction work areas manually or using mechanical sweepers, as needed, to minimize tracking of sediments on vehicle tires away from the site and to minimize washoff of sediments from adjacent streets in runoff. 6 1556a 0o5.doc �. I�. � Stormwafer Pollution Prevention Pfan Whenever possible, sediment-laden water shall be discharged into onsite, relatively level, vegetated areas (BMP C240 paragraph 5, page 4-102). In some cases, sediment discharge in concentrated runoff can be controlled using permanent stormwater BMPs (e.g., infiltration swales, ponds, trenches). Sediment {oads can limit the effectiveness of some permanent stormwater BMPs, such as those used for infiltration or biofiltration; however, those BMPs designed to remove solids by settling (wet ponds or sediment ponds) can be used during the construction phase. When permanent stormwater BMPs will be used to control sediment discharge during construction, the structure will be protected from excessive sedimentation with adequate erosion and sediment control BMPs. Any accumulated sediment shall be removed after construction is complete and the remainder of the site has been stabilized. The following BMPs will be implemented as end-of-pipe sediment controls as �equired to meet permitted turbidity limits in the site discharge(s). Prior to the implementation of these technologies, sediment sources and erosion control and soil stabilization BMP efforts will be maximized to reduce the need for end-of-pipe sedimentation controls. ■ Temporary Sediment Trap (BMP C240) ■ Construction Stormwater Filtration (BMP C251) ■ Construction Stormwater Chemical Treatment (BMP C 250) (implemented only with prior written approval from Ecology). 3.1.5 Element #5 — Stabilize Soils Exposed and unworked soils shall be stabilized with the application of effective BMPs to prevent erosion throughout the life of the project. The specific BMPs for soil stabilization that shall be used on this project include: ■ Temporary and Permanent Seeding (BMP C120) • Mulching (BMP C121) �� • Dust Control (BMP C 140) Seeding shall occur on all areas to remain unworked pursuant to below. Dust shall be controlled if construction occurs during the summer. Alternate soil stabilization BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s� listed above are deemed ineffective or inapprop�iate during construction to satisfy the ,, requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Storrnwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the altemative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, no soils shall remain exposed and unwo�lced for more than 7 days during the dry season (May 1 to September 30) 7 15564.005.doc � -��, Stormwater Poilution Preventrcn PJan and 2 days during the wet season (October 1 to Apri! 30j Regardless of the time of year. all soils shaU be stabilized at the end af the shift before a hol�day or weekend if needed based on weather forecasts. In general, cut and fili slopes wiil be stabi{ized as soon as possible and soii stockpiles wiii be temporarily covered with piastic sheeting. All stackpiled soils shall be stabilized from erosion, protected with sediment trapping measures, and where possible. be lacated away from storm drain inlets, waterways, and drainage channels. 3,1.fi Element #fi — Protect Slopes All cut and fill slapes will be designeti, constructed, and protected in a manner that minimizes erosion. The following specific BMPs will be used to protect slopes for this project� • Temporary and Permanent Seeding {BMP C 120} Temporary and permanent seeding shaH be used at all exposed areas �ursuant tfl the prior ment�aned schedule (seasonal restr;ctians}. Alternate slope protection BMPs are included in Appe�dix C as a quick re#erence tool for the ansite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during canstruction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the altemative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.7 Element #7 — Protect Drain Inlets AI! storm drain inlets and culverts made operable during construction shall be protected to prevent unfiltered or untreated water from entering the drainage conveyance system. However. the first priority is to keep ai{ access roads clean of sediment and keep street wash water separate from entering storrn drains until treatment ca� be provided. Storm Drain Inlet Protection (BMP C220)will be implemented for all drainage inlets and culverts that could potentially be impacted by sedirnent-laden runoff on and near the project site. The following inlet protection measures will be applied on this project: • Excavated Drop Inlet Protection • Block and Gravel Drop Inlet Protection • Gravel and Wire Drop Inlet Pratection • Catch Basin Filters • Culvert Inlet Sediment Trap 8 15564.045 d�r , � � � ' Stormwater Pallufion Prevenfion Pian If the BMP options listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D), or if no BMPs are listed above but deemed necessary during construction, the Certified Erosion and Sediment Gontrol Lead shall implement one or more of the alternative BMP inlet protection options listed in Appendix C. 3.1.8 Element #8 — Stabilize Channels and Outlets Where site runoff is to be conveyed in channels, or discharged to a stream ar some other natural drainage point, efforts will be taken to prevent downstream erosion. The specific BMPs for channel and outlet stabilization that shall be used on this project include: � Site runoff shali be discharged via temparary ditches to a sediment trap Altemate channel and outlet stabilization BMPs are inciuded in Appendix C as a quick reference taol for the onsite inspectar in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit {Appendix 0). To avoid potential erosion and sediment control issues that may cause a violation{s) of the NPDES Construction Stormwater pe�mit {as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, all temporary on-site �I canveyance channels shall be designed, constructed, and stabilized to prevent erosion from the expected �ak 10 minute velocity of flow from a Type 1A, 10-year, 24-haur recuRence interval �� storm for the developed condition. Alternatively, the 10-year, 1-hour peak flow rate indicated by �'� an approved continuous runoff simulatian model, increased by a factor of 1.6, shall be used. Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent streambanks, s�apes. and downstream reaches shall be provided at the outlets of all II cornreyance systems. 3.1.9 Element #9 — Control Pollutants I All pollutants, including waste materials and demolition debris, that occur onsite shall be handled and disposed of in a manner that daes nat cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, well organized, and free of debris. If required, BMPs tv be implemented ta control specific sources of poliutants are discussed below. Vehicles, construction equipment, and;or petroleum I praduct storage/dispensing: ■ All vehicles, equipment, and petroleum produet storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks ar spilis. ! ■ On-site fueling tanks and petrofeum product starage containers shall include secondary containment. 9 �ssc�oa��,�� 7 .__ t E Stormwater Pollution Prevention Plan ■ Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. ■ In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. ■ Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Demolition: ■ Dust released from demolished sidewalks, buildings, or structures will be controlled using Dust Control measures (BMP C140). ■ Storm drain inlets vulnerable to stormwater discharge carrying dust, soil, or debris will be protected using Storm Drain Inlet Protection (BMP C220 as described above for Element 7). ■ Process water and slurry resulting from sawcutting and surfacing operations will be prevented from entering the waters of the State by implementing Sawcutting and Surfacing Potlution Prevention measures (BMP C152). Concrete and grout: ■ Process water and slurry resulting from concrete work will be prevented from entering the waters of the State by implementing Concrete Handling measures (BMP C151}. 3.1.10 Element #10 - Control Dewatering �, All dewatering water from open cut excavation, tunneling, foundation work, trench, or I'', underground vaults shall be discharged into a controlled conveyance system prior to discharge ' to the downstream drainage course. Channels will be stabilized, per Element #8. Clean, non- � turbid dewatering water will not be routed through stormwater sediment ponds, and will be ;i discharged to systems tributary to the receiving waters of the State in a manner that does not I cause erosion, flooding, or a violation of State water quality standards in the receiving water. II Highly turbid dewatering water from soils known or suspected to be contaminated, or from use of construction equipment, will require additio�al monitoring and treatment as required for the specific pollutants based on the receiving waters into which the discharge is occurring. Such � monitoring is the responsibility of the contractor. A dewatering plan shall be submitted to the City for their approval prior to the start of construction. However, the dewatering of soils known to be free af contamination will trigger BMPs to trap sediment and reduce turbidity. At a minimum, geotextile fabric socks/bags/cells will be used to filter this material. Other BMPs to be used for sediment trapping and turbidity reduction include the following: ■ Goncrete Handling (BMP C151) 10 15564.005.doc ! � � Sformwater Po!lution Prevention Plan Concrete shail be handied pursuant to BMP C151 wherever and whenever concrete is mixed and poured at the project site. Alternate dewatering control BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Cert�ed Erosion and Sediment Control Lead will promptly initiate the imp{ementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.11 Element #11 — Maintain BMPs All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP's specifications. Visual monitoring of the BMPs will be conducted at least once every calendar week and within 24 hours of any rainfall event that causes a discharge from the site. If the site becomes inactive, and is temporarily stabilized, the inspection frequency will be reduced to once every month. All temporary erosion and sediment control BMPs shall be removed within 30 days after the final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil resulting from removal of BMPs or vegetation shall be permanently stabilized. , 3.1.12 Element #12 — Manage the Project Erosion and sediment control BMPs for this project have been designed based on the following principles: � Design the project to fit the existing topography, soils, and drainage patterns. � Emphasize erosion control rather than sediment control. ■ Minimize the extent and duration of the area exposed. ■ Keep n.inoff velocities low. ■ Retain sediment on site. • Thoroughly monitor site and maintain all ESC measures. ■ Schedule major earthwork during the dry season. In addition, project management will incorporate the key components listed below: II As this project site is located west of the Cascade Mountain Crest, the project will be managed according to the following key project components: 1 1 ':5�� 005 doc � 1�' Stormwafer Pollution Prevention Plan Phasing of Construction ■ The construction project is being phased to the extent practicable in order to prevent soil erosion, and, to the maximum extent possible, the transpo�t of sediment from the site during construction. ■ Revegetation of exposed areas and maintenance of that vegetation shall be an integral part of the clearing activities during each phase of construction, per the Scheduling BMP (C 162). Seasonal Work Limitations ■ From October 1 through April 30, clearing, grading, and other soil disturbing activities shall only be permitted if shown to the satisfaction of the local permitting authority that silt-laden runoff will be prevented from leaving the site through a combination of the following: O Site conditions including existing vegetative coverage, slope, soil type, and proximity to receiving waters; and � Limitations on activities and the extent of disturbed areas; and ❑ Proposed erosion and sediment control measures. ■ Based on the information provided and/or local weather conditions, the local permitting authority may expand or restrict the seasonal limitation on site disturbance. ■ The following activities are exempt from the seasonal clearing and grading limitations: � Routine maintenance and necessary repair of erosion and sediment control BMPs; a Routine maintenance of public facilities or existing utility structures that do not expose the soil or result in the removal of the vegetative cover to soil; and O Activities where there is 100 percent infiltration af surface water runoff within the site in approved and installed erosion and sediment con#rol facilities. Coordination with Utilities and Other Jurisdictions ■ Care has been taken to coordinate with utilities, other construction projects, and the locat jurisdiction in preparing this SWPPP and scheduling the construction work. Inspection and Monitoring ■ All BMPs shail be inspected, maintained, and repaired as needed to ass�re continued performance of their intended function. Site inspections I 1 2 �5564 U05 dx i f"`, i � � , S,or,mwoter Pollution Preventior Plan shali be conducted �y a person who is knowiedgeable in the principles I and practices of erosion and sedime�t controL Thfs person has the 'i necessary skilis to I ❑ Assess the s�te con�+itians anc construction ac#ivities that could impact the quality of stormwater, and ❑ Assess the effectiveness of eras�an and sediment contro� meas�res �as�d to control the quality of stormwater discMarges. ■ A Certified Erasion and Sediment Control Lead shaH be on-site or on-call at ali times. ■ Whenever inspectian and/or monitoring reveals that the BMPs identified in this SWPPP are inadequate, due to the actual discharge of or potential ta discharge a significant amount of any polfutant, appropriate BMPs or design changes shall be implemented as soan as possible. Maintaining an Updated Construction SWPPP ■ This SWPPP shall be retained on-site or withfn reasonabMe access to the site. ■ The SWPPP shall be modified whenever there is a change in the design, constructian, operation, or maintenance at the const�uction site that has, or could have, a significant effect on the discharge of pollutants to waters of the state. ■ The SWPPP sh.all be mocif�ed if. durirg inspections or investigatians conducted by the owner/operator, or the applicable local or state reguiatory authority, it is determined that the SWPPP is ineffec#ive in eliminating or significantly minimizing pollutants in stormwater discharges from the site. The SWPPP shall be modified as necessary to include additional a{ modified BMPs designed to correct problems identified. Revisions to the SWPPP shall be completed within seven (7} days following the inspection. 3.1.13 Element #13 - Construction Stormwater Chemical Treatment Turbidity is difficult to contro! once fine particles are suspended in stormwater runoff from a construction site. Sedimentation ponds are effective at removing larger particulate matter by gravity settiing, but are ineffective at removing smaller particulates such as clay and fine silt Sediment ponds are fypically designed to remove sediment nQ smaller than medium silt (0.02 mm}. Chemical treatment may be used to reduce the turbidity of stormwater runoff. Ghemical treatment can reliably provide exceptianal reductions of turbidity and associated pollutants. Very high turbidities can be reduced to levels comparable to what is found in streams during dry weather. Traditional BMPs used ta contro! soil erosion and sediment loss from sites under development may not be adequate to ensure compliance with the water quality standard for turbidity in the receiving water. Chemical treatment may be required to protect 13 15564.Od5 dc_= , � Stormwater Pollution Prevention Plan streams from the impact of turbid stormwater discharges, especially when construction is to proceed through the wet season. Formal written approval from Ecology and the Local Permitting Authority is required for the use of chemical treatment regardless of site size. The intention to use Chemical Treatment shall be indicated on the Notice of Intent for coverage under the General Construction Permit. Chemical treatment systems should be designed as part of the Construction SWPPP, not after the fact. Chemical treatment may be used to correct problem sites in limited circumstances with formal written approval from Ecology and the Local Permitting Autho�ity. The SEPA review authority must be notified at the application phase of the project review (or the time that the SEPA determination on the project is performed) that chemical treatment is proposed. If it is added after this stage, an addendum will be necessary and may result in project approval delay. See Appendix II-B for background information on chemical treatment. Criteria for Chemical Treatment Product Use Chemically treated stormwater discharged from construction sites must be nontoxic to aquatic organisms. The following protocol shall be used to evaluate chemicals proposed for stormwater treatment at construction sites. Authorization to use a chemical in the field based on this protocol does not relieve the applicant from responsibility for meeting all discharge and receiving water criteria applicable to a site. ■ Treatment chemicals must be approved by EPA for potable water use. ' ■ Petroleum-based polymers are prohibited. ■ Prior to authorization for field use, jar tests shall be conducted to demonstrate that turbidity reduction necessary to meet the receiving , water criteria can be achieved. Test conditions, including but not limited to raw water qualiry and jar test procedures, should be indicative of field , conditions. Although these small-scale tests cannot be expected to reproduce performance under field conditions, they are indicative of treatment capabiliry. • Prior to authorization for field use, the chemically treated stormwater shall ' be tested for aquatic toxiciry. Applicable procedures defined in ' Chapter 173-205 WAC, Whole Effluent Toxicity Testing and Limits, shall be used. Testing shall use stormwater from the construction site at which the treatment chemical is proposed for use or a water solution using soil from the proposed site. 14 1556a.005 a��,� .- f Siarm,water Paliution Preventio!� P+an ■ The proposed maximum dosage shall be at least a factor of five lower than the no observed effects concentration (NOEC). ■ The approval of a propased treatment chemicai shail be conditional, subject to fuli-scale bioassay monitoring af treated stormwater at the � construction site where the proposed treatmen# chemical is to be used. I ■ Treatment chemicals that have already passed the above testing protocal I' do not need to be reevaluated. Contact the Department of Ecology ', Regional Office for a list of treatment chemicals that have been evaluated ' and are currently approved for use. ' Treatment System Design Cansiderations The design and operatiQn of a chemical treatment system should take into consideratian the factors that determine optimum, cost-effective performance. It may not be possible to fully incorporate all of the classic concepts into the design because of practical limitations at construction sites. Nonetheless, it is important to recagnize the following: ■ The right chemical must be used at the right dosage. A dasage that is either too low or tao high will not produce the lowest turbidity. There is an optimum dosage rate. This is a situatian where the adage "adding more is always better" is not#he case. • The coagulant must be mixed rapidly into the water to insure proper dispersion. ■ A flocculation step is important to increase the rate of settling, to produce the lowest turbidity, and to keep the dosage rate as low as possib4e. ■ Too little energy input into the water during the flocculation phase results in fiocs that are #oo small andJor insu�ciently dense. Too much energy can rapidly destroy floc as it is formed. ■ Since the volume of the basin is a determinant in the amount of energy per unit volume, the size of the energy input system can be tao small relative to the volume of the basin. ■ Care must be taken in the design of the withdrawal system to minimize o�tflow velocities and to prevent floc discharge. The discharge shauld be directed through a physical filter such as a vegetated swale that would catch any unintended floc discharge. 15 �s5sa oo�doc ; �� Stormwafer Poilution Prevention Plan Treatment System Design Chemical treatment systems shail be designed as batch treatment systems using either pands or portable trailer-mounted tanks. Fiow-through continuous treatment systems are nat ailowed at this time. A chemical treatment system consists of the stormwater coilection system (either temporary diversion or the permanent site drainage system), a sto�age pond, pumps, a chemical feed system, treatment cells, and interconnecting piping. The treatment system shall use a minimum of two lined treatment cells. Multiple treatment cells allow far clarification of treated water while other cells are bei�g filled or emptied. Treatment celfs may be ponds or tanks. Pands with constructed earthen embankments greater than six feet high require special engineering analyses. Partable tanks may afso be suitable for some sites. The following equipment should be located in an operatio�s shed: ■ the chemical injector; • secondary containment for acid, caustic, buffering compound, and treatment chemical; • emergency shower and eyewash, and ■ rnonitoring equipment which consists of a pH meter and a #urbidimeter. Sizing Criteria The combination o#the storage pond ar other halding area and treatment capacity shoutd be large enough to treat stormwater during multiple day storm events. It is recommended that at a minimum the storage pond or ather holding area shauld be sized to hold i.5 times the runoff volume of the 10-year, 24-hour storm event. Bypass should be provided around the chemical treatment system ta accommodate extreme storm events. Runoff volume shall be calculated using the methods presented in Volume 3, Chapter 2. !f no hydrologic anaiysis is required for the site, the Rational Method may be used. Primary settling should be encouraged in the storage pond. A forebay with access for maintenance may be beneficial. There are two opposing considerations in sizing the treatment cells. A larger cell is able to treat a larger volume of water each time a batch is processed. However, the larger the cell the longer the time required to empty the cell. A larger cell may also be less effective at flocculation and therefore require a longer settling time. The simplest approach to si2ing the #reatment cell is to multiply the allowable discharge flow rate times the desired drawdown #ime. A 4-hour drawdown time allows one batch per cell per 8-hour work period, given 1 hour af flocculation followed by twa hours of settling, 16 15564.005.doc � �`� i Stormwater Pallutron Prevent;or Ptan The permissible discharge rate governed by potential downstream effeci can be used to caiculate the recommended size of the treatment celis. The foilowing discharge fiow rate limits shall apply: • If the discharge is directly or indirectly to a stream, the discharge fiow rate shall not exceed 50 percent of the peak flow rate of the 2-year, 24-hour event for all starm events up to the 10-year, 24-hour event. ■ If discharge is occurring during a storm event equal to or greater than the 10-year, 24-hour event, the allowable discharge rate is the peak flow rate of the 10-year, 24-hour event. ■ Discharge to a stream should not increase the stream flow rate by more than 10 percent. ■ If the discharge is directly ta a lake, a major receiving water listed in Appendix C of Volume I, or to an infiltratian system, there is no discharge flow limit. ■ If the discharge is to a municipal storm drainage system, the allowable discharge rate may be limited by the capacity of the public system. it may be necessary to clean the municipal storm drainage system prior to the start of the discharge to prevent scouring solids from the dfainage system. • Runoff rates shall be calculated using the methods presented in Volume 3, Chapter 2 for the pre-developed conditiQn. If no hydralogic analysis is required for the site, tne Rational Method may be used. Monitoring The following monitoring shall be conducted. Test results shall be recorded on a daily log kept on site: Ot�erational Monitoring ■ pH, cvnductivity (as a sur�ogate for alkalinity), turbidity and temperature of the untreated stormwater ■ Total volume treated and discharged • Discharge time and flow rate ■ Type and amaunt of chemical used for pH adjustment ■ Amount of polymer used for treatment ■ Settling time 17 15564 oL��aoc � Stormwater Pollution Prevention P/an Compliance Monitorinq ■ pH and turbidity of the treated stormwater ■ pH and turbidity of the receiving water Biomonitorina: Treated stormwater shall be tested for acute (lethal)toxicity. Bioassays shall be conducted by a laboratory accredited by Ecology, unless otherwise approved by Ecology. The performance standard for acute toxicity is no statistically significant difference in survival between the control and 100 percent chemically treated stormwater. Acute toxicity tests shall be conducted with the following species and protocols: � Fathead minnow, Pimephales promelas (96 hour static-renewal test, method: EPA/600/4-90l027F�. Rainbow trout, Oncorhynchus mykiss {96 hour static-renewal test, method: EPA/600/4-90/027F} may be used as a substitute for fathead minnow. ■ Daphnid, Ceriodaphnia dubia, Daphnia pulex, or Daphnia magna (48 hour static test, method: EPA/60014-90/027F). All toxicity tests shall meet quality assurance cnteria and tsst conditions in the most recent versions of the EPA test method and Ecology Publication #WO-R-95-80, �aboratory Guidance and Whole Effluent Toxicity Test Review Criteria. Bioassays shall be performed on the first five batches and on every tenth batch thereafter, or as otherwise approved by Ecology. Failure to meet the performance standard shall be immediately reported to Ecology. Discharge Compliance: Prior to discharge, each batch of treated stormwater must be sampled and tested for compliance with pH and turbidity limits. These limits may be ,, established by the water quality standards or a site-specific discharge permit. Sampling and testing for other pollutants may also be necessary at some sites. Turbidity must be within 5 NTUs of the background turbidity. Background is measured in the receiving water, upstream from the treatment process discharge point. pH must be within the range of 6.5 to 8.5 standard units and not cause a change in the pH of the receiving water of more than 0.2 standard units. It is often possible to discharge treated stormwater that has a lower turbidity than the receiving water and that matches the pH. Treated stormwater samples and measurements shall be taken from the discharge pipe or another location representative of the nature of the treated stormwater discharge. Samples used for determining compliance with the water quality standards in the �eceiving water shall not be taken from the treatment pond prior to decanting. Compliance with the water quality standards is determined in the receiving water. 18 15564.005 dcc Stormwater Pollution Prevention Plan Operator Training Each contractor who intends to use chemical treatment shall be trained by an experienced contractor on an active site for at least 40 hours. Standard BMPs Surface stabilization BMPs should be implemented on site to prevent significant erosion. All sites shall use a truck wheel wash to p�event tracking of sediment off site. Sediment Removal and Disposal ■ Sediment shall be removed from the storage or treatment cells as necessary. Typically, sediment removal is required at least once during a wet season and at the decommissioning of the cells. Sediment remaining in the cells between batches may enhance the settling p�ocess and reduce the required chemical dosage. ■ Sediment may be incorporated into the site away from drainages. 3.1.14 Element #14 — Construction Stormwater Filtration Filtration removes sediment from runoff originating from disturbed areas of the site. Traditional BMPs used to control soil erosion and sediment loss from sites under development may not be adequate to ensure compliance with the water quality standard for turbidity in the ', receiving water. Filtration may be used in conjunction with gravity settling to remove sediment as small as fine silt (0.5 Nm). The reduction in turbidity will be dependent on the particle size , d�stribution of the sediment in the stormwater. In some circumstances, sedimentation and ! filtration may achieve compliance with the water quality standard for turbidity. I Unlike chemical treatment, the use of construction stormwater filtration dces not require � approval from Ecology. � Fi{tration may also be used in conjunction with polymer treatment in a portable system to assure capture of the flocculated solids. Design and Installation Specifications— Background Information Filtration with sand media has been used for over a century to treat water and wastewater. The use of sand filtration for treatment of stormwater has developed recently, generally to treat runoff from streets, paricing lots, and residential areas. The application of filtration to construction stormwater treatment is currently under development. Two types of filtration systems may be applied to construction stormwater treatment: �apid and slow. Rapid sand filters are the typical system used for water and wastewater treatment. They can achieve relatively high hydra�lic flow rates, on the order of 2 to 20 gpm/sf, because they 19 1556d.005.doc / �'�v Stormwater PoOution Prevention Plan I, have automatic backwash systems to remove accumulated solids. in contrast, slow sand filters have very low hydraulic rates, on the order of 0.02 gpm/sf, because they do not have backwash systems. To date, slow sand filtration has generally been used to treat stormwater. Slow sand filtration is mechanically simple in comparison to rapid sand filtration but requires a much larger ' filter area. Filtration Equipment Sand media filters are available with automatic backwashing features that can filter to 50 {�m particle size. Screen or bag filters can filter down to 5 Nm. Fiber wound filters can remove particles down ta 0.5 Nm. Filters should be sequenced from the largest to the smallest pore opening. Sediment removal efficiency will be related to particle size distribution in the stormwater. Treatment Process Description Stormwater is collected at interception point(s) on the site and is diverted to a sediment pond or tank for remova! of large sediment and storage of the stormwater before it is treated by the fiitration system. The stormwater is pumped from the trap, pond, or tank through the filtration system in a rapid sand filtration system. Slow sa�d filtration systems are designed as flow through systems using gravity. If large volumes of concrete are being poured, pH adjustment may be necessary. Maintenance Standards Rapid sand filters typically have automatic backwash systems that are triggered by a pre-set pressure drop across the filter. If the backwash water volume is not large or substantially more turbid than the stormwater stored in the holding pond or tank, backwash return to the pond or tank may be appropriate. However, land application or another means of treatment and disposal may be necessary. ■ Screen, bag. and fiber filters must be cleaned andior replaced when they become clogged. ■ Sediment shall be removed from the storage and/or treatment ponds as necessary. Typically, sediment removal is required once or twice during a wet season and at the decommissioning of the ponds. 3.2 Site Specific BMPs Site specific BMPs are shown on the TESC Plan Sheets and Details in Appendix A. These site specific plan sheets will be updated annually. 20 ��s�oc5 do� � i � ` ' , . � Stormwater Pollution Prevention Plan 4.0 Construction Phasing and BMP Implementation The BMP implementation schedule wiil be driven by the construction schedule. The foilowing provides a sequentia! list of the proposed construction schedule milestones and the corresponding BMP implementation schedule. The list contains key milestones such as wet season construction. The BMP implementation schedule listed below is keyed to proposed phases of the construction project, and reflects differences in BMP installations and inspections that relate to wet season construction. The project site is located west of the Cascade Mountain Crest. As such, the dry season is considered to be from May 1 to September 30 and the wet season is considered to be from October 1 to April 30. • Estimate of Construction start date: June 2016 ■ Estimate of Construction finish date: June 2017 ■ Mobilize equipment on site: ■ Mobilize and store all ESC and soil stabilization products (store materials on hand BMP C150): ■ Install ESC measures: ■ Install stabilized construction entrance: � Begin clearing and grubbing: � ■ Temporary erosion control measures (hydroseeding): ■ Site inspections reduced to monthty: � Begin concrete pour and implement BMP C151: ■ Excavate and install new utilities and services (Phase 1): • Complete utility const�uction: ■ Begin implementing soil stabilization and sedime�t control BMPs throughout the site in preparation for wet season: • WET SEASON STARTS: October 1. 2016 21 15564.005-do� � •f Stormwater Pollution Prevention Plan 5.0 Pollution Prevention Team 5.1 Roles and Responsibilities The pollution prevention team consists of personnel responsible for implementation of the SWPPP. including the following: ■ Cert�fied Erosion and Sediment Control Lead (CESCL) — pnmary contractor contact, responsible for site inspections (BMPs, visual monitoring, sampling, etc.); to be called upon in case of failure of any ESC measures. ■ Resident Engineer— For projects with engineered structures only (sediment ponds/traps, sand filters, etc.): site representative for the owner that is the projecYs supenrising engineer responsible for inspections and issuing instructions and drawings to the contractor's site supervisor or representative ■ Emergency Ecology Contact— individual to be contacted at Ecology in case of emergency. Go to the following website to get the name and number for the Ecology contact information: http://www.ecy.wa.gov/org.html. • Emergency Owner Contact— individual that is the site owner or representative of the site owner to be contacted in the case of an emergency. ■ Non-Emergency Ecology Contact— individual that is the site owner or representative of the site owner than can be contacted if required. ■ Monitoring Personnel—personnel responsible for conducting water quality monitoring; for most sites this person is also the Certified Erosion and Sediment Control �ead. 22 15564 OG5 doc II / 1� � Stormwater Pollution Prevention Plan 5.2 Team Members Names and contact information for those identified as members of the pollution prevention team are provided in the following table. Title Name(s) Phone Number Certified Erosion and Sediment Control Lewis Conklin (425) 284-3300 Lead (CESCL) Resident Engineer Ali Sadr (425) 251-6222 Emergency Ecology Contact Staff on Duty (360) 407-6242 Emergency Owner Contact Renton Land Acquisition (972) 934-8698 Non-Emergency Ecology Contact Ali Sadr (425) 251-6222 Monitoring Personnel Lewis Conklin (425) 284-3300 23 15564 GOS do� ' 1 i,7 Stormwater Pollution Prevention P/an 6.0 Site Inspections and Monitoring Monitoring inciudes visual inspection, monitoring for water quality parameters of concern, and documentation of the inspection and monitoring findings in a site log book. A site log book will , be maintained for all on-site construction activities and will include: ■ A record of the implementation of the SWPPP and other permit requirements; ■ Site inspections; and, ■ Stormwater quality monitoring. For convenience, the inspection form and water quality monitoring forms included in this SWPPP include the required information for the site log book. This SWPPP may function as the site Ic�g book if desired, or the forms may be separated and included in a separate site log book. However, if separated, the site log book but must be maintained on-site or within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. 6.1 Site Inspection All BMPs will be inspected, maintained, and repaired as needed to assure continued perFormance of their intended function. The inspector will be a Certified Erosion and Sediment I Control Lead (CESCL) per BMP C160. The name and contact information for the CESCL is provided in Section 5 of this SWPPP. Site inspection will occur in all areas disturbed by construction activities and at all stormwater ', discharge points. Stormwater will be examined for the presence of suspended sediment, �, turbidity, discoloration, and oily sheen. The site inspector will evaluate and document the I effectiveness of the installed BMPs and determine if it is necessary to repair or replace any of � the BMPs to improve the quality of stormwater discharges. All maintenance and repairs will be documented in the site log book or forms provided in this document. All new BMPs or design , changes will be docurnented in the SWPPP as soon as possib�e. 6.1.1 Site Inspection Frequency Site inspections will be conducted at least once a week and within 24 hours following any rainfall event which causes a discharge of stormwater from the site. For sites with temporary stabilization measures, the site inspection frequency can be reduced to once every month. 6.1.2 Site Inspection Documentation The site inspector will record each site inspection using the site log inspection forms provided in Appendix E. The site inspection log forms may be separated from this SWPPP document, but will be maintained on-site or within reasonable access to the site and be made available upon �equest to Ecology or the local jurisdiction 24 1556d.005 doc ' i Stormwater Pollution Prevenf�or Plan 6.2 Stormwater Quality Monitoring ' 6.2.1 Turbidity Sampling , Monitoring requirements for the proposed project will include either turbidity or water 'i transparency sampling to monitor site discharges for water quality compliance with the 2010 � update Constnaction Stormwater General Permit (Appendix D). Sampling will be conducted at I all discharge {�ints at least once per calenda�week. i Turbidity or transparency monitoring will follow the analytical methodologies described in Section S4 of the 2005 Construction Stormwater General Permit(Appendix D}. The key benchmark values that require action are 25 NTU for turbidity (equivalent to 32 cm transparency) and 250 NTU for turbidity (equivalent to 6 cm transparency). If the 25 NTU benchmark for turbidity (equivalent to 32 cm transparency) is exceeded, the following steps will be conducted: 1. Ensu�e all BMPs specified in this SWPPP are installed and functioning as intended. 2. Assess whether additional BMPs should be implemented, and document revisions to the SWPPP as necessary. 3. Sample discharge location daily until the analysis results are less than 25 NTU (turbidity) or greater than 32 cm (transparency). If the turbidity is greater than 25 NTU (or transparency is less than 32 cm) but less than 250 NTU (transparency greater than 6 cm)for more than 3 days, additional treatment BMPs will be implemented within 24 hours of the third consecutive sample that exceeded the benchmark. If the 250 NTU benchmark for turbidity (or less than 6 cm transparency) is exceeded at any time. the following steps will be conducted: 1. Notify Ecology by phone within 24 hours of analysis (see Section 5.0 of this SWPPP for contact information). 2. Continue daily sampling until the turbidity is less than 25 NTU {or transparency is greater than 32 cm). 3. Initiate additional treatment BMPs such as off-site treatment, infiltration, filtration and chemical treatment within 24 hours of the first 250 NTU exceedance. 4. Implement additional treatment BMPs as soon as possible, but within 'I 7 days of the first 250 NTU exceedance. ' 5. Describe inspection results and remedial actions taken in the site log book and in monthly discharge monitoring reports as described in Section ' 7.0 of this SWPPP. 25 ^5564 od�doc t � Stormwater Pollution P�eventron Pfan 6.2.2 pH Sampling Stormwater runoff will be monitored for pH starting on the first day of any activity that includes more than 40 yards of poured or recycled concrete, or after the application of"Engineered Soils" � such as Portland cement treated base, cement kiln dust, or fly ash. This does not include fertilizers. For concrete work, pH monitoring will start the first day concrete is poured and continue until 3 weeks after the last pour. For engineered soils, the pH monitoring period begins when engineered soils are first exposed to precipitation and continue until the area is fully stabilized. Stormwater samples will be collected daily from all points of discharge from the site and measured for pH using a calibrated pH meter, pH test kit, or wide range pH indicator paper. If the measured pH is 8.5 or greater, the following steps will be conducted: 1. Prevent the high pH water from entering storm drains or surface water. 2. Adjust or neutralize the high pH water if necessary using appropriate technology such as CO�sparging {liquid or dry ice}. 3. Contact Ecology if chemical treatment other than CO2 sparging is planned. 26 �5564 oG5 doc J ,� `l Stormwater Pollution Prevention Pian 7.0 Reporting and Recordkeeping 7.1 Recordkeeping 7.1.1 Site Log Book A site log book will be maintained for all on-site construction activities and will include: ■ A record of#he implementation of the SWPPP and ather permit requirements; ■ Site inspections; and, ■ Stormwater quality monitoring. For convenience, the inspection form and water quality monitoring forms included in this SWPPP include the required information for the site logbook. 7.1.2 Records Retention Records of all monitoring information (site log book, inspection reportslchecklists, etc.), this Stormwater Pollution Prevention Plan, and any other documentation of compliance with permit requirements v►rill be retained during the life of the construction project and for a minimum of three years following the terrnination of permit coverage in accardance with permit condition , SS.C. ', 7.1.3 Access to Plans and Recards ' The SWPPP, General Permit, Notice of Authorization letter, and Site Lag Book will be retained I on site or within reasonable access to the site and will be made immediately available upon li request to Ecology or the local jurisdiction. A copy of this SWPPP will be provided to Ecology within 14 days af receipt of a +nrritten request for the SWPPP from Ecology. Any other information requested by Ecology will be submitted within a reasonable time. A copy of the SWPPP or access #o the SWPPP will be provided to #he public when requested in writing in ac�ordance with Pe�mit Condition SS.G. 7.1.4 Updating the SWPPP In accordance with Conditions S3, S4.6, and S9.B.3 of the General Permit. this SWPPP will be modified if the SWPPP is ineffective in eliminating ar significantly minimizing pollutants in stormwater discharges from the site or there has been a change in design, construction, operation, or maintenance at the site that has a significant effect on the discharge, or patential for discharge, of�llutants to the waters of the State. The SWPPP will be modified within seven days of determination based on inspection(s)that additional or modified BMPs are necessary to correct prablems identified, and an updated timeli�e for BMP implementation will be prepared. 27 15564.005.doc Sto�mwate,• Po,�utr�n Preve�t;on Pran 7.2 Reporting 7.2.1 Discharge Monitoring Reports Discharge Monitoring Report {DMR) forms will be submitted to Ecology �ecause �vater quality sampling is being conducted at the site 7.2.2 Notification of Nancompliance If any of the terms and conditions of the permit are not met. and it causes a threat to human health or the environment, the following steps will be taken in accordance with permit section S5 F 1 Ecology will be immed�ately notified a`the failure to comply 2. Immediate action will be taken to control the noncompliance issue and to correct the problem. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5)days, unless requested earlier by Ecology. 28 isssa oos do� ; " Stormwater Pollution Prevention Plan Appendix A — Site Plans 29 �sssa.005 do� � �- � ,oT A E.� TEMPORARY EROSION AND SEDIMENT CONTROL PLAN - - " , N , t . ; : rF.s.c. �rro i S;�pRGAN � , �$. _ r�. � OEXNIP'!Id: PROPO'SEC � / f �5 30 60 I ' i � \ ^ ! �i. � � a FtTER�A9R�C F£MCf � �- \ J TE�FC1Rwt :s+$'4'J:.'i0M ENTOANCE � I � \ + � . `� b ROIe u+?:Tt �� \Q � �� '*,S'� • _ . ._ �� _�.._�.._.� _ v .. , . RTER�� E�KE � . __ _ ��C h1P01+u�: Daid�w:E D�*.� �OEiNi pa;•� ,_�E /.. " N \' :r- h � ^ NOG tHECK ow 3�- Ex. ]p. .'�'VEz :b - „� `�g �/... . tMTS Of CEAIEMG '�� 7 � ,—Q�jq� � � ;O . � � . . f UIK{TYv.) _- . 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(�ZS)ZS�-6222 ��i EEp OtO� -� '�,BCYE �00[._._ �� W ro� � - "• _ �^. qSppNsg�n 7*�(CP�nP�C•ry� Ct7rb�tnr�G EMGwEtRi.K '�NESOtv[��ErS oRp��C�aCEE7Mc wM �.ts)n,-e�� c�x �•E�+.��N ' Z CS5:4.iCiON — ow. py�y� car,cr ow a��cw �� C4 ,F 16 m � / Stormwater Po!lubon Prevention Plan Appendix B — Construction BMPs Preserving Natural Vegetation (BMP C101) High Visibility Plastic or Metal Fence (BMP C103) Stabilized Construction Entrance (BMP C105) Silt Fence (BMP C233) Sedime�t Trap (BMP C240) Temporary and Permanent Seeding (BMP C120) Mulching (BMP C121) Dust Control (BMP C140) Check Dams (BMP C207) Construction Stormwater Chemical Treatment (Bt�1P C25Q1 Construction Stormwater Filtration (BMP C251� 30 1556a.o05.do� i 4.1 Source Control BMPs BMP C101: Preserving Natural Vegetation Purpose The purpose of preserving natural vegetation is to reduce erosion�t:ere�er practicable, Limiting site disturbance is the single most ef�'ecti��e method for reducing erosion. For example, conifers can hold up to about 50 �rcent of all rain that falls during a storm. Up to 20-30 percent of this rain may ne�er reach the ground but is taken up by the tree ar evaporates. Another benefit is that the rain held in the tree can be released slou�lv to the ground after the storm. Conditio�rs of L'_se • Natural vegetatian should be preser�-ed on steep slopes, near perennial and intermittent watercourses or swales, and on building sites in wooded areas. • �� equired by local govemments. De�ig�r and �atural �egetation can be preserved in natural clumps or as individual I►rstallation trees, shrubs and vines. _S��eci f catinns � The presen�ation of individual plants is more difficult because hea�� equipment is generally used to remove unwanted vegetation. The points to remember when attempting to save individual plants are: • ts the plant worth sa�=ing? Consider the location, species, size,age, �i`or,and the work invoh�ed. Local govemments may also have ��rcinances to save natural vegetation and trees. • Ferce or clearly mark areas around trees that are to be saved. It is �rcferable to keep ground disturbance aw-ay from the trees at least as f3r out as the dripline. Pi��nts need protection from three kinds of injuries: • C nrrstruction Equrpment- This injwy can be abo��e or below the ,rt�und le��el. Damage results from scarring, cutting of roots, and cu;>>paction of the soil. Placing a fenced buffer zone around plants to he saved prior to construction can prevent construction equipment i nj uries. • Gr�rde Changes- Changing the natural ground level w�ill alter grades, ��hich affects the plant's ability to obtain the necessary air, w�ater. and minerals. Minor fills usually do not cause problems although ;ensitiviry ben�reen species does��ary and should be checked. Trees ean tolerate fill of 6 inches or less. For shrubs and other plants, the fill shc�uld be less. l��hen there are major changes in grade, it may become necessary to supply air to the roots of plants. This can be dane by placing a layer of `�ra�el and a tile system o��er the roots before the fill is made. A tile -t-2 Volume 11-Construction Stormwater Pollufion Prevention February 2005 ! �i� �� stem pratects a tree ti�om a raised grade. The tile st,tem should be �I laid out on the original grade leading from a dry well around the tree trunk. The system should then be covered w-ith smali stones to allo« air to circulate over the root area. Low•ering the natural ground level can seriously damaee trees and shrubs. The highest percentage of the plant roots are in the upper 12 ' inches of the soil and cuts of only 2-3 inches can cause serious injury. To protect the roots it may be necessary to terrace the immediate area ar�und the plants to be sa��ed. If roots are exposed, construction of retaining walls may be needed to keep the soil in place. Plants ean also be presen�ed by leaving them on an undisturbed. �ently sloping mound. To increase the chances for survival, it is best to limit grade changes and other soil disturbances to areas outside tl�e dripline of the p!ant. • �.��c•m�ations- Protect trees and other plants when exca�ating for drainfields,po«-er, water, and sew�er lines. Vi��ere possible,the trenches should be routed around trees and large shn;bs. When this is not possible, it is best to tunnel under them. This can be done«�ith hand tools or with pov�er augers. If it is not possible to route the trench around plants to be saved, then the following si�ould be observed: Cut as few roots as possible. When you have to cut, cut clean. Paint �ut root ends w7th a wood dressing like asphalt base paint. E3ackfill the trench as soon as possible. "t-unnel beneath root s��stems as close to the center of the main trunk to ;�reserve most of the important feeder roots. �rme problems that can be encountered with a few specific trees are: • tlaple, Dagwood, Red alder, Vi-'estem hemlock, Vl�'estern red cedar, a��d Douglas fu do not readily adjust to changes in en�ironment and <��ecial care should be taken to protect these trees. • l he w�indthrow hazard of Pacific silver fir and madro�tna is high, w�hile chat of Western hemlock is moderate. The danger of��•indthrow increases v►•here dense stands have been thinned. Other species (unless tl�ey are on shaUow, wet soils less than 20 inches deep) have a low ��indthrow hazard. • CUttonwoods, maples, and willows have water-seeking roots. These .:an cause trouble in se«-er lines and infiltration fields. On the other I hand, the� thrite in hi��?� moisture �onditions tl�at c�ther trees ��ould �I nc�t. • Thinning o�erations in }�ure or �3�i�ed ;tands of Gran�� tir, Pacitic sil�er tir. tioble iir, Sitka sF�ru�e, 1��estern red c�dar, ��'este:�n hemlock. �� __ _ __ _– — -- -- February 2005 l'oJume !(- G�r,strucfrcn Stor•n✓�aler Pollutron Preven!ior a-3 � - � �. ', Pacific dogw�aod, and Red alder can cause serious disease problems. Disease can become established through damaged limbs, trunks, roots, and freshly cut stumps. Diseased and weakened trees are also susceptible to insect attack. ."Nainrenance • lnspect flagged and/or fenced areas regularly to make sure flagging or Standards fencing has nat been remo�-ed or damaged. If the flagging or fencing has been damaged or visibilin� reduced, it shall be repaired or replaced immediately and��isibiliry restored. • If tree roots have been eaposed or injured, "prune" cleanly «�ith an appropriate pruning saw or lopers directly above the damaged roots and reco��er ��ith nati��e soils. Treatment of sap flow�ing trees (fir, hemlock, pine, soft maples) is nat ad��ised as sap forms a natural healing barrier. ---- -- - -- - --- -- - - - - 4-4 l ;�i�e !1- Consfruction Stormwa!er Pollution Prevention FeLruary 20C�5 , � t , ; BMP C103: High Visibility Plastic or Metal Fence Purpose Fencing is intended to: (l ) restrict clearing to approved limits; (2)prevent disturbance of sensitive areas, their buffers,and other areas required to be left undisturbed; (3) limit construction traffic to designated construction entrances or roads; and, (�) protect areas ��here marking w�ith survey tape may not provide adequate protection. Conditions of Use To establish clearing limit:, plastic or metal fence may be used: • At the boundary of sensiti��e areas,their buffers, and other areas required to be left uncleared. • As necessary•to contr�l vehicle access to and on the site. Design aad • High visibility plastic fence shall be composed of a high-densiry Insta/lation polyethylene material and shall be at least four feet in height. Posts Specifrcations for the fencing shall be steel or wood and placed e�-ery 6 feet on � center(maximum)or as needed to ensure rigidity. The fencing shall be fastened to the post e��ery six inches w�ith a polyethylene tie. nn long continuous lengths of fencing, a tension wire or rope shall be used as a top stringer�c, prevent sagging betv��een posts. The fence color shall be high �ri�ibility orange. The fence tensile strength �hall be 360 lbs./ft. using the ASTM D4595 testing method. • Metal fences shatl be designed and installed according to thc manufacturer's specifications. • Metal fences shall be at least 3 feet high and must be hi;hl� �i�ihl�. • Fences shall not be vvired or stapled to trees. :lfaintenance • If the fence has been damaged or visibility reduced, it �hall be Sta►rdardc repaired �r re�laced i�,�mediatelv and �isihilih� restare�i. 4-6 Volume !1-ConstrucUon Stormwater Pollution Prevention February 2005 i �' � BMP C105: Stabilized Construction Entrance Purpose Construction entranczs are stahiliz�d t�� redu�� th� .�muunt of.�dit��nt transported onto pa�•ed roads by�ehicles or equipment by constr��tin<� a stabilized pad of quarry spalls at entrances to construction sites. (�o,rdi�io►r.c ,>J�[ ser Construction entrances shall be stabilized w-herever traffic will hc lea�in�� a construction site and travelin�= ��n �a�ed re�a�i� r�� ther �a�ed area� ��ithin 1,000 feet of the site. i�n large commercial, high«a�, and ruad projects. �'�c dr��ner :ho�ild include enough extra materials in the contract to allo� tor additional �{��bilized entrances not show�n in the initial Constructian SV4'PPP. It i� ditficult to determine exactly where access ta these projects u•ill take place; additional materials will enable the contractor to install them �ti hcr� r:«ded. Dc�sig,r u�:d • See Figure 4.2 for details.Note: the l 00' minimum length of thc l,rsmllation entrance shall be reduced to the m�imum praeticable size when ihc .S'peciTcatians size or configuration of the site does not allo�t the full length (1 i�t>'i • 1 separation geotextile shall be placed under the sgalls to pre�ent tine sediment from pumping up into the rock pad. The g�ote�til� �hall meet the follow�ing standards: � Grab Tensile Strength {ASTM 04751} 200 psi min. Grab Tensile Elongation (ASTM D4632) 30% max. Mullen Burst Strength (ASTM D3786-80a) 400 psi min AOS(ASTM D4751) 20-45 (U.S. standard sieve size) � • Consider early installation of the first lift of asphalt in areas that«�ill paved;this can be used as a stabilized entrance. Also cansider the irlstallation of excess concrete as a stabilized entrance. During lar�� rancrete pours, e�cess conerete is often a��ailable for this purpose. • Hog fuel (wood-based mulch)may be substituted for or combined ��th quarry spalis in areas that will not be used for permanent roads. Hog fuel is generall}� less effective at stabilizing construction entrances and �hould be used only at sites where the amount of traffic is very limited. }�og fuel is not recommended for entrance stabilization in urban areas. The effectiveness of hog fuel is highly variable and it generally requires more maintenance than quarry spalls. The inspector ma} at any time require the use of quarry spalls if the hog fuel is not preventing sediment from being tracked onto pa�•ement or if the h�� fuel is being carried onto pavement. Hog fuel is prohibited in rermanent roadbeds because organics in the subgrade soils cau�c degradation of the subgrad� support over time. • 1=encing(see BMPs C103 and G104) shall be installed as neces,an� to restrict traffic to the construction entran�e. ___-- - - -- --__ _ — ------- --_ --- — _ 4-8 Volume !1— Construct��i Stormwater Pollution P;e✓en'�on February 2005 LI : • �� fl�llt�l'C �)�>>�lE��. 1111' �111C::��:�� fla�l ��C �Ui7�l;'U�TCij t�il :3 � ii'l. �oinpacted subgrade. This can substantially incr�.�� tii� r:;��;i��:��>� of the pad and reduce the need for maintenance. 1Naintenance • Quarry spalls (or hog fuel) shall be ad�i�� if the }�a�: i� n�, l. ;,__��r ,;. Standards aceordance�cith the specifications. • If the entrance is not preventing s��im��lt fr�>>Ir i��n�� tracl.�.i ,�ni,� pa��ement, then alternative measures tu keep the streets free c�f sediment shall be used. This may include street sweeping, an increa,L in the dimensions of the entrance, or the installation of a�fleel ��a�l�. • Any sediment that is tracked onto pa�•ement shall be remo�ed b� shoti�eling or street sv►�eeping. The sediment collected by s�i ee�in,_ shall be remo�ed or stabilized on site. The pavement shall nt�i '�� cleaned by��ashing do«n the street, except when sweepin� i� ineffective and there is a threat to public safery. If it is nec��,�rti i�� -ash the streets, the constru�tion of a small sump shall be considere�. The sediment would then be ��ashed into the sump where ir can be CO11ti0I�Ct�. • :�ny quarry spalls that are loosened from the pad, which end up on the roadway shall be removed immediately. • If vehicles are entering or exiting the site at points other than the conswction entrance(s), fencing(see BMPs C103 and C1U-�) shall be installed to control traffic. • l;pon project completion and site stabilization, all construction accesses intended as permanent access for maintenance shall be ermanzntl �stabilized. o�,�.....Y mr�«n+� �e�,.s�a m. P�++�w�Y M�s nconxnad�d pu[ C+e arWanoe b� crownsd so tM1 ruro(f � wo� d�ns or tne ca0 r'' i "�r �- � � i ! IrKtaY 9�ewaY��.e' u tMre s a rwasbe d9G+presen! t'�-quarry spaY�—� Geotez:�k �.� y c i~ h��. tY m�n tirxkness l� P•ovbt tui w�h of rprefs•eprcss area Figure 4.2 -Stabilized Construction Entrance February 2005 Vc ��me i!- Construction Stormwater Poltution Pr�eventicn 4-9 ,":,", BMP C120: Temporary and Permanent Seeding Purpose Seeding is intended to reduce erosic�n by �tabilizing ��p��seci �oils. .-� ��ell-established vegetati��e co�•er is one of the most effecti��e meth��ds rt reducing erosion. Conditions of C:se ' Seeding may be used throughout the project on disturbed areas that ha��e reached final �rade or that t;-i11 remain unw�orked for more than � 30 days. �� • Channels that ��ill be ��egetated should be installed before major ' �arthv�•ork and hydroseeded with a Bonded Fiber Matrix. The �egetation should be «�ell established (i.e., 75 percent co�-er}befare ��ater is allov�•ed to flow in the ditch. With channels that w�ill have hi�h flows, erosion control blankets should be installed over the ', h�droseed. If vegetation cannot be estabiished from seed before water ' i� allov��ed in the ditch, sod should be installed in the bottom of the �3itch over hydromulch and blankets. • fZetention/detention ponds should be seeded as required. • !�iulch is required at all times because it protects seeds from heat, moisture loss, and transport due to runoff. • .�ll disturbed areas shall be review°ed in late August to early September and all seeding should be completed by the end of September. Othervti�ise,vegetation will not establish itself enough to provide more than average protection. • .�t final site stabilization, all disturbed areas not otherwise vegetated or �tabiliZed shall be seeded and mulched. Final stabilization means the �ompletion af all soil disturbing activities at the site and the ��tablishment of a permanent vegetative cover, or equivalent ��rmanent stabilization measures (such as pa��ement, riprap,gabions ��r�eotextiles)w�hich �ti�ill prevent erosion. Dc�sr��,� a,rc! • ��zding should be done during those seasons most conduci�•e to lnstallation g�'owTh and w�ill varv with the climate conditions of the region. Specificario�:s Local experienee should be used to determine the appropriate seeding periods. • The optimum seeding windows for western Washington are April 1 through June 30 and September 1 through October 1. Seeding that occurs betw�een Jul� l and August 30 will require irrigation until 75 percent grass cover is established. Seeding that occurs between October 1 and March 30 w-ill require a mulch or plastic cover until %� percent grass cover is established. • To prevent seed from being washed away, confirm that all required �urface ��ater rnntr��l measures ha�� heen installed. --- —- ---- - — ----- --- February 2005 Volu,me 11- Construction Stormwater Pollution Prevention 4-13 � `; .�, • I-he ;eedbed should be tinn ..�:�1 rou�h. :�ll soil �hould be r�,u�hened no matter what the slope. lf�ompaction is required for engineering purposes, slopes must be trac:: ��•alked before seeding. Backblading or smoothing of slopes greater t'.�an 4:1 is not allowed if they are to be seeded. • tiew and more effective restcration-based landscape practices rely on deeper incorporation than tha; provided by a simple single-pass rototilling treatment. Where�er practical the subgrade should be initially ripped to improve lor.�-term permeabiliry, infiltration, and «�ater inflow qualities. At a �:-�inimum,permanent areas shall use soil amendments to achieve orgar.ic matter and permeability performance defined in engineered soiVlar.�scape systems. For systems that are deeper than 8 inches the roto'illing process should be done in multiple lifts, or the prepared soil system shall be prepared properly and then placed to achieve the specifie� depth. I • Organic matter is the most aF:ropriate form of"fertilizer"because it provides nutrients(including :litrogen, phosphorus, and potassium) in the least water-soluble form. .-� natural system typically releases ?-i cl percent of its nutrients annua"v. Chemical fertilizers have since becn formulated to simulate �}•hat rr�anic matter does naturally. • In general, ]0-4-6 N-P-K (nitrogen-phosphorus-potassium) fertiliz�r can be used at a rate of 90 po,:nds per acre. Slow-release fertilizer� should always be used becau�e they are more efficient and ha�•e fe�� environmental impacts. It is ��zcommended that areas being seeded f�r final landscaping conduct soi: tests to determine the exact h�pe and quantiry of fertilizer needed. This w-ill pre��ent the o�•er-application ��1 fertili2�r. Fertilizer should nc�t be added to the hydromulch mach�ne and agitated more than 20 mi��:utes before it is to be used. If agitated too much, the slow°-release ci ating is destroyed. • There are numerous product a��ailable on the market that take tl�c place of chemical fertilizers. These include several w�ith sea��erd ettracts that are beneficial to �oil microbes and organisms. If 1 t)0 percent cottonseed meal is u�.d as the mulch in hydroseed, chemical fertilizer may not be necessar.. Cottonseed mcal is a ��,d ,�,urce oi long-term, slow-release, avai;able nitrogen. • Hydroseed applications shall :nclude a minimum c�f 1,�00 p��un�i� E�cr aere of mulch with 3 percent :ackifier. Mulch may be made up of 1 i►(i percent: cottonseed meal; fihers made of wood, recycled cellulose. hemp, and kenaf; compost; o� blends of these. Tackifier shall be planc- based, such as guar or alpha F�antago, or chemical-based such as polyacrylamide or polymers. .-�ny mulch or tackifier product used shall be installed per manufa�'��rer's instructions. Generall�, mulchr: come in 40-50 pound ba`T�. �.:�1 ,�n�i f�rtilizer ar� ac3�ic� at ti;»� ��t t,,,li�ati��. � I.} _--- __ __ - -- ----- - 4-i 4 '✓o,.��;e I1- Ccnsiruchon StormwaiE =u��ution Preve��trcn F�r,ruary 20G5 ��.�: • �1ul�h i� .�l��a�� required fc>r �ee�in�. �li�lch can hc appli�d ��n t��p ��t the seed or simultaneously by hydroseeding. • On steep slopes, Bonded Fiber Matrix(BFM)or Mechanically Bonded Fiber Matri� (MBFM) products should be used. BFM/MBFM products are applied at a minimum rate of 3,000 pounds per acre of mulch with approximately 10 percent tackifier. .Application is made so that a minimum of 95 percent soil co�erage is achieved. Numerous products are available commercially and should be installed per manufacturer's instructions. Most products require 24-36 hours to cure before a rainfall and cannot be installed on„�et or saturated soils. Generally. these products come in 40-50 pound bags and include all necessary ingredients except for seed and fertilizer. HF�is and MBFMs have some advantages o�•er blankets: • '�o surface preparation required; • Can be installed via helicopter in remote areas; • On slopes steeper than 2.5:1, blanket installers may need to be roped and harne�sed for safery; • They are at least $],000 per acre cheaper installed. (n most cases, the shear strength of blankets is not a factor w�hen used on slopes, only�hen used in channels. BFMs and;vIBFMs are good alternatives to blankets in most situations wfiere vegetation establishment i� the goal. • When installing seed ��ia hydroseeding operations, only about 1/3 of the seed actually ends up in contact with the soil surface. This reduces che ability to establish a good stand of grass quickly. One �ti�ay to I ��ercome this is to increase seed quantities by up to 50 percent. � • �'egetation establishment can also be enhanced by dividing the h�dromul�h operation into tvvo phases: 1 Phase 1- Install all seed and fertilizer w�ith 25-30 percent mulch and ta�kifier onto soil in the first lift: �. Phase?- Install the rest of the mulch and tackifier over the first lift. :-�n alternative is to install the mulch, seed, fertilizer, and tackifier in one litt. Then, spread or blow straw over the top of the hydromulch at a rate of about 800-1000 pounds per acre. Hold stra��in place with a standard tackifier. Both of these approaches will increase cost moderately but will greatly impro�e and enhance vegetative establishment. The increased cost I ma�� be offset by the reduced need for: '! 1. Imgation �. Rea lication of mulch PP � Repair nf failed slope surfaces - -- - - - - _ ___ _ 'i Febru�y 2005 Volume ll- Cc� s'ructron Storrrwater Pollutior� F�evenficn 4-1~ ?�'� I This technique u�orks w•ith standard hydromulch (1,�00 pounds per acre minimum) and BFM/I�1BFh4s (3,000 pounds per acre minimum). • Areas to be permanently landscaped shall provide a healthy topsoil that reduces the need for fertilizers, impro��es overall topsoil quality, provides for better vegetal health and vitaliry, improves hydrologic characteristics, and reduces the need for irrigation. This can be accomplished in a number of w•ays: Recent research has sho��n that the best method to impro�e till soils is to amend these soils ��ith compost. The optimum mixture is approximately tw�o parts soil to one part compost. This equates to 4 inches of compost mixed to a depth of 12 inches in till soils. Increasing the concentration of compost beyond this level can ha�-e negative effects on vegetal health, «•hile decreasing the concentrations can reduce the benefits of amended soils. Please note: The compost should meet specifications for Grade A quality compost in Ecology Publication 9�-038. c)ther soils, such as gra��el or cobble outwash soils, may require different approaches. Organics and fines easily migrate tlirough the loose structure of these soils. Therefore,the importation of at least 6 inches of quality topsoil, underlain by some type of filter fabric to prevent the migration of fines, may be more appropriate for these soils. .�reas that already have good topsoil, such as undisturbed azeas, do not r-tyuire soil amendments. • �reas that will be seeded only and not landscaped may need compost ��r meal-based mulch included in the hydroseed in order to establish ��zetation. Native topsoil should be re-installed on the disturbed soil .urface before application. • Seed that is installed as a temporary measure may be installed by hand i f it will be co�•ered by straw, mulch, or topsoil. Seed that is installed as a permanent measure may be installed by hand on small areas (usually less than 1 acre)that will be covered with muich, topsoil, or erosion blankets. The seed mixes listed below include recommended mixes for both temporary and permanent seeding. These mixes, with the exception of the wetland mix, shall be applied at a rate of 120 pounds per acre. This rate can be reduced if soil amendments or slow- release fertilizers are used. Local suppliers or the local conservation district should be consulted for their recommendations because the appropriate mix depends on a variety of factors, including location, � exposure, soil rype, slope, and expected foot traf�ic. Alternati��e seed � mixes approved by the local authority may be used. 4-16 Volume ll-Consbuction Stormwater Pollution Prevention February 2005 �� I�ahle �.1 rcpresents thc ;tan�iarci mi� 1�.,r th��;� area; �t�}.�r� �u•t a temporar}��egetative co��er is required __._ ___ _ _ __ __-_____ ____, Table 4.1 Tem ora Erosion Control Seed Mix %��"ei ht %Purih %Germination s Chevvings or annual blue grass 40 98 90 ¢ Festrrca rubra var. commutata or Poa am�a Perennial rve- �0 9$ 90 Lolium erenne Redtop or colonial bentgrass 5 92 SS � ostis alba or A rostis tem�is � VVhite dutch clo��er 5 98 90 a Trifolium re ens Table 4? pro��ides just one recommended possibility for landscaping seed. Table 4.2 Landsca in Seed Mix %V4'ei ht %Purin °/.Germinatioo j Perennial rve blend 70 98 90 Loliumper�n�ie � __ _---- _ ---- -- _---____�_----------- � Chew-ings and red fescue blend � 30 98 90 ! Festuca rubra var. comniutata � or Festuca rubra This turf seed mix in Table 4.3 is for dn� situations«here there is nc, need for much ��ater. The advantage is that this mix requires ven litcle maintenance. Tabie 4.3 Low-Growin TurF Seed Mix °/. N'ei ht %Puriri� %Germination h D�ti�arf tall fescue(several varieties) 45 98 90 j Festuca arunr,�inacea var. � Dwarfperennial rye(Barclay) 30 98 90 ; Lolium enne var. barc! � Red fescue 20 i 48 90 Festuca rubra Colonial bentgrass � 5 98 90 .4 roslis lerrurs Table 4.4 presents a mi� recommenc�ed for hica.��ales ancl ��ther itltermittently��•et area�. Table 4.4 Bioswale Seed Mix* %V4'ei ht °/.Purih• %Germinadon Tall or meadow fescue i 5-80 4R 90 Festuca arundinaeea or Fesruea elat�or Seaside;'Creeping bentgrass 10-15 92 85 A ostis lustris Redtop bentgrass 5_�0 ` 90 80 A ostis alba or.4 roslis i antea 1f�Qe'��. ��l:�l'lil�� i'A �'1[' �ft�� r�5['Cil� � t�:,i�� {��!F;l!7e�e CF<'1�.11!\ _ .__—.____-- __—_._—_--—._ - —_—._ _..._ _. �=ebruary 20CJ5 Vplume �i— Ga�struc!ion St�rmurater Po(!�;rro�� Preverfron -�,-'7 The seed mix shown in Table 4.5 is a recommended low-growing, relatively non-invasive seed mix appropriate for�•ery�•et areas that are not regulated ��etlands. �ther mixes may be appropriate, depending on the soil ty�pe and hydrology of the azea. Recent research suggests that bentgrass(agrostis sp.) should be emphasized in v►et-area seed mixes. Apply this mi�ture at a rate of 60 pounds per acre. Table 4.5 Wet Area Seed Mix' %��ei ht °/.Purih °/a Germination Tal]or meadoN fescue f�;?-�0 98 90 Fesiuca art,ndirracea or Festuca elar;or Seaside Creepi�lg bentgrass 10-15 98 85 .4 ostis lustris '.�IeadoH foxtail ]0-15 90 80 Ale ocuruspratensis Alsike clover I-6 98 90 Trifolium hi hridum __ __ __ __ __ Redtop bentgras, 1-6 92 85 .4 rosti_s alhu Y 1 fodilred Bricr,kreen. Inc. Hrdrnseeding Guide H'�-tlands Seed:Nir The meadow� �eed mix in Table 4.6 is recommended for areas that will be maintained infrequently or not at all and ��here colonization by nati��e plants is desirable. Likely applications include rural road and utility right- of-way. Seeding should take place in September or very early October in order to obtain adequate establishment prior to the winter months. The appropriateness of clover in the mix may need to be considered, as this can he a fairly invasive species. If the soil is amended, the addition of clover �nay not be necessary. Table 4.6 Meadow Seed Mix %��'ei 6t %Purih� %Germina6oe Redtop or Oregon bentgrass �0 9� 85 , A ostis alba or.4 ostis ore onensis Red fescue �0 98 90 Festuca rubra W'hite dutch clo�er !0 98 90 Tri olium re�ens Ilainrena,rce • Any seeded areas that fail to establish at least 80 percent cover(100 Srandard.c percent co�er for areas that receive sheet or concentrated flows)shall be reseeded. If reseeding is ineffective, an alternate method, such as ,,,dding, mulching, or nets/blankets, shall be used. If winter v�•eather prevents adequate grass growTh, this time limit may be relaxed at the discretion ��f the local authoriry when sensitive areas v��ould othen�•ise he prc�tcct��. -- --_ ___. __ _ __ 4-18 Volume ll—Construction Stormwater Pollution Pr�vention February 2005 i �� • .=�ft�r ad�quate co�er i� arhie�cd, am areas that c�pcncnc� en�sion shall be reseeded and protected by mulch. If the erosion problem is drainage related, the problem shall be fixed and the eroded area reseeded and protected by mulch. • Seeded areas shall be supplied��ith adequate moisture, but not watered to the eztent that it causes runoff. - _ --- - -_ -- -- _ _ _-— -- -- _ February 20G5 Vo�ume !!- Construction S!ornr,�•ater Pollution Prevention 4-19 ��L� �I BMP C121: Mulching Purp�ce T'he ��urpose of mulching soils is to pro��ide immediate temporary protection from erosion. Mulch also enhances plant establishment by consen�ing moisture,holding fertilizer, seed, and topsoil in place, and moderating soil temperatures. There is an enormous ��ariety of mulches that can be used. Only the most common types are discussed in this secti�n. Cnnditio�rs of('ce .�s a temporary cover measure, mulch should be used: • On disturbed areas that require co��er measures for less than 30 days. • As a cover for seed during the ��et season and during the hot summer m�mths. • During the w�et season on slopes steeper than 3H:1 V with more than 10 f«t of vertical relief. • �i ulch may be agplied at any time of the yeaz and must be refreshed F�:riodically. Decig�r and For�nulch materials, appiication rates, and specifications, see Table 4.7. /�rstal/ation Note: Thicknesses may be increased for disturbed areas in or near .Specifrcations sensiti��e areas or other areas highh susceptible to erosion. \lulch used w7thin the ordinary high-��ater mark of surface �vaters should be selected to minimize potential flotation of organic matter. Composted or�anic materials have higher specilic gxa��ities (densities)than straw, ��ood, or chipped material. tluinre�rance • The thickness of the co�-er must be maintained. � .S�c„rdurdc � ,,,,� azeas that experience erosion shall be remulched and/or protected I �� :ih a net or blanket. tf the erosion problem is drainage related, then t'�c ��r��hl�m ;hall h� tix�d and t'•:� �ruded arca remulch�d 420 Volume !l—Construction Stormwater Pollution Prievention February 2005 �t��i Table 4.7 Mulch Standards and Guidelines Mulc6 Applicatioo ;1laterial uali �Standsrds Rates Remarks Straw .Air-dried;free from 2"-3"thick;5 Cost-effective protectior ,�hen applied with adequate undesirable seed and bales per I000 sf thickness. Hand-applics',�n generally requires greater coarse material. or 2-3 tons per thickness than blow-n su_.�.The thickness of straw�may be acre reduced by half when��:�i in conjunction w�ith seeding. In H•ind��areas straw must-�held in place by crimping,using a tackifier,or co�ering H i: netting. Blown straw always has to be held in place with� 'ackifier az even light w•inds Will blow it away.Straw,ho•• e�er.has se.eral deficiencies that should be considered wl-::i selecting mulch materials.It often introduces and'or e-�courages the propagation of W�eed species and it has no sig: �icant long-term benefiu. Scraw should be used only ifrr.i,hes with long-term benefits are una��ailable locall�. It sF �uld also not be used Hithin the ordinary high-aater ele�..�.i��n of surface a aters(due to flotation). Hydrom�:ch No groWth Approx_'S-30 Shall be applied w ith h}�•omuic}►er. Shall not l�used � inhibiting factors Ibs per 1000 sf without seed and tackifi�- unless the application rate is at or I500 -2p00 least doubled. Fiben lo _er than about'4-I inch clog � Ibs per acre h}•dromulch equipment. ibers should be kept to less than'. inch. Composted '.�lo visible water or 2"thick min.; '�tore cffecti�•e control c_.•� he obtained by increasing Mulch ar.d dust during approx. 100 tons thickness to 3". Excelle:: mulch for protecting final grades Compost handling. Must be per acre(approx. until landscaping becau�. it can be directh•seeded or tilled purchased from 8001bs per yard) into soil as an amendme�:. Composted mulch has a coarser supplier w�ith Solid size gradation than comF ��t. It is more stable and practical Waste Handling to use in wet areas and� -ing rainy weather conditions. Permit(unless exempt). Chipped �ite Average size shall 2"minimum This is a cost-effective«.� co dispose of debris from I �'egetati<<n be seceral inches. thickness clearing and�rubbing,a• .: it eliminates the problems Gradations from associated with burning. :,enerally,it should not be used on fines to 6 inches in slopes above approx. 10` because of its tendenc��to be length for texture, transported by�runoff. It �not recommended w�ithin 200 variation,and feet of surface w•aters. If ceeding is expected shortl� after i interlocking mulch,the decompositir of the chipped vegetation may tie properties. up nutrients important to _r�s establishment. Wood-ba�ed No visible water or 2"thick;approx. This material is often ca �d'`hog or hogged fuel." It is Mulch dust during 100 tons per acre usable as a material for 5�.abilized Construction Entrances handling. :Nust be (approx.800 Ibs. (BMP C105)and as a m�.ch. The use of mulch ultimately i purchased from a per cubic yard) improves the organic ma-er in the soil. Spocial caution is '; supplier with a Solid ad�-ised regazding the so.�ce and composition of w�ood- t Waste Handling based mulches. lu prepc-ation t}�picalh�dces not provide I Permit or one an}�w�eed seed control,s ��idence of residual vegetation in exempt from solid its composition or know�- :nclusion of weed p]ants or seeds I waste regulations. should be monitored and �revented(or minimized). � - -- — --- — __ _ _--- — Februar-✓ 2�G5 L'ofwne !I- Constructron Stormwafer Pol(utron Pr-.c�;tici� 4-21 BMP C140: Dust Control Purpuse Dust control prevents w�ind transport of dust from disturbed soil surfaces onto roadways,drainage ways, and surface�vaters. Conditioiu uf C:�c� • In areas(including road��ays) subject to surface and air movement of dlist ��here on-site and off-site impacts to roadu�ays, drainage v��ays, or surface waters are likely. Design and • Vegetate or mulch areas that will not receive vehicle traffic. In areas Installation where planting, mulching, or paving is impractical, apply gravel or Specifrcations landscaping rock. • Limit dust generation by clearing only those areas ��here immediate acti�•ity will take place, leaving the remaining area(s) in the original c��ndition, if stable. '�laintain the original ground co��er as long as E�ractical. . (�,,nstruct natural or artificial w�indbreal:s or H-indscreens. These may h� designed as enclosures for small dust sources. • S��rinkle the site w•ith water until surface is wet. Repeat as needed. To E�re��ent carryout of mud onto street, refer to Stabilized Conswction Fntrance (BMP C105). • lrrigation v��ater can be used for dust controL Irrigation systems should be installed as a first step on sites where dust control is a concern. • Spray ezposed soil areas with a dust palliative, follo�ving the rT�anufacturer's instructions and cautions regarding handling and �,rplication. Used oil is prohibited from use as a dust suppressant. L��cal governments may approve other dust palliati�es such as calcium �h 1 oride or PA:VI. • P �'vI (BMP C 126)added to v��ater at a rate of 0.5 Ibs. per 1,000 ��allons of w•ater per acre and applied from a water truck is more ' �ffective than water alone. This is due to the increased infiltration of ��ater into the soil and reduced evaporation. In addition, small soil particles are bonded together and are not as easily transported by wind. Adding PAM may actually reduce the quantity of v��ater needed for dust control,especially in eastern Washington. Since the wholesale cost of PAM is about � 4.00 per pound,this is an extremely cost- effective dust control method. Techniques that can be used for unpaved roads and lots include: • Low•er speed limits. High vehicle speed increases the amount of dust stirred up from unpa�ed roads and lots. , • Upgrade the road surface strength by improving particle size, shape, ' and mineral types that make up the swface and base materials. ' 4-40 Volume/l-Conshuction Stormwafer Pollution Prevention February 2005 �,�D • :1dd �uri:.�� ra��l to reduce the ��urce ��f dust emissi��n. Lim�t th� amount ��:� fi�i� }�arnrl�s Ith��e ,maller than .f1-� inm� t�� 1(? tt� �(i percent. • Use geot��ul� fabi-�c:, t�� inrr�s�e th� �tr�n��th ��1 n�� r��a�i; c�r r��a�i. undergoing reconstruction. • Encourage the use of alternatc, pa��d route,, it a�ailablc. • Restrict use by tracked vehicles and hea�ry trucks to pre�ent daii�a�� : road surface and base. • Apply chemical dust suppressants using the admix method, blendin_ the produ::t��ith the top few inches of surface material. Suppressant� may also re applied as surface treatments. • Pave unpaved permanent roads and other trafficked areas. • Use vacuum street sweepers. • Remo�e �,U�� ,111(j ��l�1tT' C�1T'l 4lit�i11��1�� t� li �j��C� 11��1 l�t"\ 3T1C� f�l�ll 1U1"I1 into dust. • Limit du�:-�:.U�lI1L' ��l�C�i 011 �llllt�\ 1��:�>. • Contact�ow local Air Pollution Contr��l :�uth��rit� 1ur ��uician�e ;�n.l training�n other dust control measures. Compliance ��-ith the local a Pollution Control Authority constitutes complian�� itli thi� B�1t' .�faintena�rce Re�pra�� arza :�� nece�can tc� kee� dust t� a 1liinimum � Standards ___ _ --- - Febre,sry 2C05 Volume ll- Cc s;�uctron Stom,wafer Pcllutiorl P;e✓enUon 4-�" BMP C207: Check Dams Purpose Crnstrucuun ot,mall da�us acr��s a s��ale or �itch redu�z� th: ��1�,�it� ,�f concentrated t1ow�and dissipates energy at the check dam. Conditions of Use �'here temporary channels or permanent channels are not ��et �,��etated. channel linin�is infeasible, and�elocity checks are required. • Check dams may not be placed in streams unless approved hti the State Department of Fish and Wildlife. Check dams may not hc �lace� �n �i�etlands without approval from a permitting agency. • Check dams shall not be placed belaw the expected back�a ater frorn ' any salmonid bearing water betu�een October 1 and '��iay ;1 to en;ure that there is no loss of high flow refuge habitat i��r c�ti en�i�:c�r;ng juvenile salmonids and emergent salmonid fi-`�. Design and 1'�hatever material is used,the dam should form a trian�le «h::; �ie��ed Insta!lation from the side. This prevents undercutting as water flow•s o�er :he tac� c�t Specifications the dam rather than falling directly onto the ditch bottom. Check dams in association �i ith sumps w�ork more effecti�el� .:t �lu��in� flo«�and retaining sediment than just a check dam alone. A d,:}� �um�� should be pro��ided immediately upstream of the check dam. • In some cases, if carefully located and designed, check da�� an remain as permanent installations w•ith very minor regradin�. The� may be left as either spillways, in w�hich case accumulated sedim��it ��ould be graded and seeded, or as check dams to prevent further sediment from leaving the site. • Check dams can be constructed of either rock or pea-gravel tiiled ba�7s. Numerous new products are also available for this purpose. They t�nd to be re-usable, quick and easy to install, effecti��e, and cost efficient. • Check dams should be placed perpendicular to the flow� of�t ater • The maximum spacing betu�een the dams shal] be such that the tc�� t the ��trea�� dam i� at the ;.�me ele�ati,,n a� thz t�,p of th� �_io��n�trz�m dam. • Keep the ma�i�num hei�;ht at , f�et at the .:znter aft}.e �ar.__ • Keep the center of the check dam at least 12 inches lo«�er than th� outer edges at natural ground elevation. • Keep the side slopes of the check dam at 2:1 or flatter. • Key the stone into the ditch banks and extend it beyond the abutment� a minimum of 18 inches ta a�oid ��ashouts from overflo�- ar�und the dam. - _- --- __ ---------- — --- ___ _— February 2005 Vciume Il— Construction Sformwater Pollutron Prevention 4-,'S : .i :., . • Use filter fabric foundation under a rock or sand bag check dam. 1 f a blanket ditch liner is used, this is not necessary. A piece of organic or synthetic blanket cut to fit will also work for this purpose. • Rock check dams shall be constructed of appropriately sized rock. The rock must be placed by hand or by mechanical means (no dumping of rock to fonn dam) to achieve complete coverage of the ditch or swale and to ensure that the center of the dam is lower than the edges. The rock used must be large enough to stay in place given the expected design flova through the channel. • In the case of grass-lined ditches and s��ales, all check dams and accumulated sediment shall be remo��ed w�hen the grass has matured sufficiently to protect the ditch or sw�ale- unless the slope of the s��ale is greater than 4 percent. The area beneath the cherk �a��» �hal l l�� seeded and mulched immediateh after dam remo�al. • Ensure that channel appurtenances, such as culven cntran,�: h�1�� check dams, are not subject to damage or blockage fri}n� �ii.�)a:��i st�nes. Figure 4.13 depicts a typical rock check dam. .�laintenance Check dams shall be monitored for performance and sedii��>>t Standards accumulation during and after each runoffproducing rainfall. S�d�m.nt shall be removed when it reaches one half the sump depth. • Anticipate submergence and deposition above the che�k �ia�1� an,j erosion from high flow�s around the edges of the dam. • If significant erosion occurs bern een dams, install a �r�,t��ti�e :ii�rap , �3�,CF' l.'1 ��i:i1 ��t�t�Uc�'1 t��t tl� �l;lfli7�'� 476 Volume 1!- Construction Stormwater PolJution Prevention February 2005 � . � � View Looking Upstream , �s• �o.3m� — �-- � , '� q ,� , ` '� �� 12' (150mm} , � �� E `'� ") �i ; - - _ p��,�3,,r �,� � `: ��`�� i�, ��=-; �'� ,.�- . 1 * GQ� oc�- � e� �y o��i //\ 24'(0.6m) I oc `SC o�j•v�v � � . �. � < ' �o.o ��~ � NOTE: '�c �� : ��,� � [ Key stone into channel banks and �-' -'� I extend it beyond the abutments a � minimum of 18" (O.Sm)to prevent A ffow around dam. Section A - A �� FLOW � �--- 24'(O.6m) o �'`''�� •°°��`�r ;;,� o �,��., r'�°..O �_��,- ,t o L� o� � , '/��;�j\ a� :��,,j� ��= / ' � �,. 8'(2.4m) Spacing Between Check Dams �L'=the distance such that points�A'and 'B'are of equal elevation. •�, _--_ �s-.,��^ ._.� ;-�° '�'''�- �: �—POINT'A' POINT'B' ,��,�A � -��-�� .� �l � _ �—� ,_ ,�\/��.1�;':��•\.�\,� �1 .:��'�x�-,ti,...,� ,�. -f'£:r �, ��, - - NOT TO SCAtE Figure 4.13 - Check Dams February 2005 Volume 1!- Const�uctron S;e�„��ti•ater Pa�luticn Prevent;�;7 �?-77 �� BMP C233: Silt Fence Purpose Use of a silt fence reduces the transport of coar;e sediment from a construction site by providing a temporary ph}�sical barrier to sediment and reducing the runoff velocities of o��erland tlo�t�. See Figure 4.l 9 for details on silt fence construction. Conditions of Use Silt fence may be used dow�nslope of all disturbed areas. • Silt fence is not intended to treat concentrated flov��s, nor is it intended '� to treat substantial amounts of o�erland flow. Any concentrated flc�� must be com�eyed through the drainage system to a sediment pond The only circumstance in which overland flo�� can be treated solel� h� a silt fence,rather than by a sediment pond, is when the area drainine to the fence is one acre or less and flow rates are less than 0.5 cfs. • Silt fences should not be constructed in streains or used in V-shaped ditches. ?he}� are not an adequate method of silt control for an}nhin� deeper than sheet or overland flow. Joints in fiRer fabric shall be spliced at posts.Use staples.wire rings or 2•x2"by 14 Ga.wire or equivalent to attach fabr�c to pests equivalent,d standard___ -T.--�----�_.,:::...._ -- s!rength fabric used � ( � - =i'er tabnc , - : - � E ___ N I , '___ � i ^-�- - _ � - ___�T-._�C, -- - - — - -� � / � �-�E ' -�►-6'max ---� Minimum 4'x4'trench - , ' N �-' --` Backfill trench with native soil j- —1-T Post spaci�g may be increased or 3.�4'-1.5'washed gravel to 8'it wire badcing is used i� 2'x2'wood posts,steel fence �sts,or equivalent Figure 4.19—Silt Fence Design and • Drainage area of l acre or less or in combination �•ith sediment basin Jnstallation in a larger site. Specifrcations • Maximum slope steepness (norn�al (perpei�dirular) to fence line) I :1 • Maximum sheet or o�erland flo�•path length to the fence of 100 fect • No flows greater than 0.5 cf��. • The geotextile used shall mcet che t��ll��in�� :tandards ��11 <��ot��tilc properties listed below•are minimum average roll values (i.e., th� t��i result for an�� sampled roll in a l�t shall meet or e�ceed the valu�� sho��n in Tahle 4.10): 4-94 Volume ll— Construction Stormwater Pollution Prevention February 20G5 ; i - Table 4.10 Geotextile Standards Pi�l}meric Mesh AOS 0.60 mm ma��mum for slit film ao�ens(#30 sieve). 0.30 �AST�1 D4751) mm maximum for all other geotextile h•pes(#50 sie��e). � 0.15 mm minimum for all fabric rypes(u100 sie�e). VI'ater Permittivity 0.02 sec" minimum (ASTM D4491) � i Grab Tensile Streng[h ; l80 lbs.Minimum for extra strength fabric. , r�$T!�1 D463�) 100 Ibs minimum for standard strength fabric. ��rab Tensile Svength ' 30%maximum ': i aSTM D4632) ' i l Itra�iolet Resistance 70%minimum `. i �>STM D4355) • Standard sVength fabrics shall be supported ��ith wire mesh, chicken ��ire, 2-inch x 2-inch wire, safety fence, or jute mesh to increase the �;rength of the fabric. Silt fence materials are a��ailable that ha�•e �z nthetic mesh backing attached. • ! ilter fabric material shall contain ultraviolet ray inhibitors and �cabilizers to provide a minimum of six months of expected usable c��nstruction life at a temperature range of 0°F. to 120°F. • I ti0 percent biodegradable silt fence is available that is strong, long I:i�ting, and can be left in place after the project is completed, if pern�itted by local regulations. • �tandard Notes for construction plans and specifications follo��. Refer �,� Figure 4.19 for standard silt fence details. Ti�e contractor shall install and maintain temporary silt fences at the I��cations showm in the Plans. The silt fences shall be constructed in tl�e areas of clearing,grading, or drainage prior to starting those activities. A silt fence shall not be considered temporary if the silt fence must function beyond the life of the contract. The silt fence �t�all prevent soil carried by runoffw�ater from going beneath, through, or over the top of the silt fence, but shall allow the water to pass through the fence. The minimum height of the top of silt fence shall be 2 feet and the n�aximum height shall be 2'/� feet above the original ground surface. Tiie geotextile shall be sew�n together at the point of manufacture, or at a�� approved location as determined by the Engineer, to form geotextile I I�ngths as required. All sew�n seams shall be located at a support post. :�lternatively,tvvo sections of silt fence can be overlapped, provided ihe Contractor can demonstrate, to the satisfaction of the Engineer, that tl�e overlap is long enough and that the adjacent fence sections are �(use enough together to prevent silt laden water from escaping tl:r��u�?h the fence at the ��erlap. i - — ------------ -___ _ ----- --- - -- _ -- __ --- - — February 2005 Volume ll- Construction Stormwafer Pcllution Preven,tron 4-95 ✓ ` � The geote�tile shall be attached on the up-slope side of the posts and support system with staples, wire, or in accordance with the ' manufacturers recommendations. The geotextile shall be attached to the posts in a manner that reduces the potential for geotextile tearing at the staples,wire, or other connection device. Silt fence back-up support for the geotestile in the form of a w•ire or plastic mesh is dependent on the properties of the geotextile selected for use. If wire or plastic back-up mesh is used, the mesh shall be fastened securely to the up-slope of the posts with the geotextile being up-slope of the mesh hack-up support. T}ie geotextile at the bottom of the fence shall be buried in a trench to a minimum depth of 4 inches below the ground surface. The trench •llal] be backfilled and the soil tamped in place over the bwied portion ��f the geotextile, such that no flow can pass beneath the fence and >��uring can not occur. When w�ire or polymeric back-up support �i�esh is used, the wire or polymeric mesh shall extend into the trench a n�inimum of 3 inches. The fence posts shall be placed or driven a minimum of 18 inches. A minimum depth of 12 inches is allov��ed if topsoil or other soft �ubgrade soil is not present and a minimum depth of 18 inches cannot t�� reached. Fence post depths shall be increased by 6 inches if the f�»ce is located on slopes of 3:1 or steeper and the slope is perpendicular to the fence. If required post depths cannot be obtained, the posts shall be adequately secured by bracing or guying to prevent o�erturning of th� fence due to sed'unent loading. Silt fences shall be located on contour as much as possible, except at ;he ends of the fence, where the fence shall be turned uphill such that th� silt fence captures the runoffwater and pre��ents w•ater from tlo�ti•ing around the end of the fence. 1 t�the fence must cross contours, with the exception of the ends of the fence, aravel check dams placed perpendicular to the back of the fence shall be used to minimize concentrated flow� and erosion along the back of the fence. The gravel check dams shall be approximately l- foot deep at the back of the fence. It shall be continued perpendicular to the fence at the same elevation until the top of the check dam intercepts the ground surface behind the fence. The gravel check dams shall consist of crushed surfacing base course, gravel backfill for walls, or shoulder ballast. The gravel check dams shall be located every I 0 feet along the fence where the fence must cross contours. The slope of the fence line where contours must be crossed shall not be steeper than 3:]. Wood, steel or equivalent posts shall be used. Wood posts shall have minimum dimensions of 2 inches by 2 inches by 3 feet minimum length, and shall be free of defects such as knots, splits, or gouges. 496 Volume 11—Construction Sto►mwater Pollution Prevention Februery 2005 �+ � Steel posts shall consist of either size No. 6 rebar or larger, AST'�1 A 120 steel pipe with a minimum diameter of l-inch, U, T, L, or C shape steel posts w�ith a minimum w�eight of 1.35 lbs.ift. or other steel posts having equivalent strength and bending resistance to the post sizes listed. The spacing of the support posts shall be a maximum of 6 feet. Fence back-up support, if used, shall consist of steel ��ire «-ith a maximum mesh spacing of 2 inches, or a prefabricated polymeric mesh. The strength of the wire or polymeric mesh shall be equivalent to or greater than 1801bs. grab tensile strength. The polymeric mesh must be as resistant to ultra��iolet radiation as the geotc�tile it supports. • Silt fence installation using the slicing method specification details follo��. Refer to Figure 4.�0 for slicing method details. The base of both end posts must be at least 2 to 4 inches above the top of the silt fence fabric on the middle posts for ditch checks to drain properly. Use a hand level or string level, if necessary, to mark base points before installation. Install posts 3 to 4 feet apart in critical retention areas and 6 to 7 feet apart in standard applications. Install posts 24 inches deep on the downstream side of the silt fence, and as close as possible to the fabric, enabling posts to support the fabric from upstream w�ater pressure. lnstall posts with the nipples facing away from the silt fence fabric. Attach the fabric to each post with three ties, all spaced «•ithin the top 8 inches of the fabric. Attach each tie diagonally 45 degrees through I the fabric, with each punctwe at least 1 inch��erticall�� apart. In addition, each tie should be positioned to hang on a post nipple wfien ' tightening to prevent sa�ging. Wrap approximately 6 inches of fabric around the end posts and secure with 3 ties. No more than 24 inches of a 36-inch fabric is allow�ed above ground level. The rope lock system must be used in all ditch eheck applications. The installation should be checked and corrected for any deviation before compaction. L'se a flat-bladed sho��el to tuck fabric deeper into the ground if necessary. Compaction is vitally important for effective results. Compact the soil immediately next to the silt fence fabric with the front ��heel of the tractor, skid steer, or roller exerting at least 60 pounds per square inch. Compact the upstream side first and then each side twice for a total of four trips. February 2005 Volume/l—Consfnicfion Stormwater Po/lution Pnevention 497 �� • .-�nv damage shall be repaired immediately. .'�lainterrance . If concentrated flows are evident uphill of the fence, they must be Standards intercepted and conveyed to a sediment pond. • It is important to check the uphill side of the fence for signs of the fence clogging and acting as a barrier to flow•and then causing channelization of flows parallel to the fence. If this occurs, replace the fence or remove the trapped sediment. • Sediment deposits shall either be removed when the deposit reaches approximately one-third the hei�ht of the silt fence, or a second silt fence shall be installed. • If the filter fabric(geotextile) has deteriorated due to ultra��iolet hreakdown it shall be re laced. ►.�.y Mi�Yt lOiT ilAC�Nlis �r.2t' T�r�.M.�r rw ...""--"-_ .. ._....».._.�dFa6Ac f�c»�w�y�r�as •�rea w�.k w � ��~M D' iLO�.. i ��«wr�w M�d �OiT�tTih ac+re�t r�rw A��w�iMwr��w sIw�wl�c�sry r/�Mfs�.w�r�� •�.►a.r�a�r �po�l r�cf�a �M% �MU.�w��sOw m�s4� � � // / / / � j\j�\j��\ \�\��\`/\�\/\�� _ ��\ �%��/��/�� ////// //// //�j��j//� ��j�,i/��\ ��i��\ A7UoidBrt ORAalc /�j��/,; s j �j_\\�\��\�\ •Carlrr h6Ae at po�t�n�d�d \ / / / / /��\�j\�/ \\/\\j\\j�\j�\� •tl��rsyeMp�po�Y�+intqi'e11�1a //��\�\//~\/ � �jj//�j%/�� •�d��i.P�.arr+Y noMs�+rcay �� \�\��\�\ •Nrp«c�M on�por�r+d r0'�ao�+J- NO ffl0fe U1�fl 2��O��3�'1ibf�G IM cafit wa�ar aot w�a It i�OMNd�b0'V'��OIIRd. �DI O��I1C� �� C)p�ra�on Aoa irlwd - a�er f�erc � ��bO1O 5�Fenc,e o�, � � , ��, ,,,, , .�.--� �a--- . . / '_� (J/ � � �C�"s's�ie��= �r"'�.�`Y '��' ,�`/�� 9 j ;ij� ! � � /�o\~i��- 4'�\ 4 s`�.�`�` 7�� * 200.30�1't11 �� y.� �_��,�.. . � " ,,, � , � ,..�. u,, r�e.�a��i ,�,�� y , � d'.� -° j ��: ' �'�'�� .��F��a Q `�'!?i?�+.a�`. ;y� "�.. No�arral�MI poLx g�g pi� (�^'�+*�� (1 i mm wi�� Carnplw�d t�aYfon Y6aLory pbw Y not actsptsbb b�caus�d hoA�o�tsl oomp�ec�on Figure 4.20-Silt Fence Installation by Slicing Method 4-98 Volurl?e !!- Construction Stormwater Foitutron Prevention February 2G05 � �� BMP C240: Sediment Trap Purpose A sediment vap is a small teinporary ponding area w�ith a gra�•el outlet used to collect and store sediment from sites cleared and/or graded during construction. Sediment traps, along�vith other perimeter controls, shall be in�talled before am land disturbance takes place in the drainage area. Condirinns of L'se Prior to Ica�in� a construction site, storm��ater runoff must pass through a sediment pond or trap or other appropriate sediment remo��al best management practice. Non-engineered sediment traps may be used on-site prior to an engineered sediment trap or sediment pond to provide additional sediment removai capacity. It is intended for use on sites w�here the tributary drainage area is less than � acres, with no unusual drainage features, and a projected build-out time �f six months or less. The sediment trap is a temporary measure (with a design life of approximately 6 months) and shall be maintained until the site area is permanently protected against erosion by �egetation andt`or �t ructures. ��diment traps and ponds are only effective in removing sediment do�m t�� ahout the medium silt size fraction. Runoff N�ith sediment of finer grades(fine silt and clay) w�ll pass through untreated, emphasizing the need to control erosion to the ma.�cimum e�tent first. ��"henever possible, sediment-laden water shall be discharged into onsite, r-�lati��ety level,vegetated areas (see BMP C?34-Vegetated Strip). This i� the only way to effectively remove fine particles from runoffunless :I��mical treatment or filtration is used. This can be particularly useful ,►fter initial treatment in a sediment trap or pond. The areas of release n�ust be evaluated on a site-by-site basis in order to determine appropriate I��ations for and methods of releasing runoff. Vegetated wetlands shall n��t be used for this purpose. Frequently, it may he possible to pump w�ater irom the collection point at the dow-nhill end of the site to an upslope �egetated area. Pumping shall only augment the treatment system,not ' replace it,because of the possibility of pump failure or runoff�•olume in excess of pump capaciry. All projects that are constructing permanent facilities for runoff quantiry control should use the rough-graded or final-graded permanent facilities for traps and ponds. This includes combined facilities and infiltration facilities. When permanent facilities are used as temporary sedimentation facilities, the surface area requirement of a sediment trap or pond must be met. If the surface area requirements aze larger than the surface area of the permanent facility, then the trap or pond shall be enlarged to comply with the surface area requirement. The permanent pond shall also be divided into two cells as required for sediment ponds. 4-102 Volume ll-Construction Stormwater Pollution Prevention February 2005 �� ither a pern�anent �ontro( structur� or tlae temporary contrul stru�ture (described in BI�1P C241, Temporary Sediment Pond) can be used. If a permanent control structure is used, it ma}�be advisable to partiallv resi;��t the lov��er orifice�vith gra�°el to increase residence time ��fiile still allo��in�_ det��atering of the pond. A shut-off��alve may be added to the control structure to allo��complete retention of stormwater in emergency situations. In this case, an emergency o�-erflow w�eir must be added. A skimmer may be used for the sediment trap ��utlet if appro�ed b� th� Lacal Permitting Authoritti Design and • See Figures 4.22 and �.?� for detail�. Installation , [f permanent runoff eontrol facilities �r� part c�f the pr��j�ct, the� Specifications should be used for sediment retention. • To determine the sediment trap geom�tr�, first caiculate the de�i��n surface area(SA) of the trap, measured at the int ert of the ��eir. L�� the following equation: SA = FS(Q,-I's) where Q� = Design inflo��based on thz peak discharge from the developed 2-year runoff e��ent from th� contributing drainage area as computed in the hydrologic analysis. The 10-year peak flow shall t� used if the project size. ��pe�icd timing and duration of construction, or dow�nstream conditions warrant a higher le��el of protection. If no hydrologic analysis is required, the Rational Method ma�, be used. 6 s = The settling velociry of the soil particle of interest. The 0.02 mm (medium silt)particle with an assumed densit� ��t 2.65 g/cm3 has been selected as the particl� ;�f�ii�t�r�� .��.�i has a settling �elocity (i�s) of 0.00096 ftr`ser. FS = A safery factor of 2 to account for non-ideal ,�ttlin�. Therefore,the equation for computin� surface area becomes: SA = 2 x QZ/0.00096 c�r 2080 sc�uare feet per cfs of intlo+� Note: E��en if permanent facilities ar� u,�d, th4� mu�t <ti l l ha�e a swface area that is at least as large as that derived fro»> t}lc ah�� formula. If they do not, the pond must be enlarged. • To aid in determining sediment depth. all sediment �ra�� hal! ha�� ., �tait�"��.�� it}� .� }�r�,m;n�nt m,trl: 1-t��t ;�1�.��e t)te h��ttom ��ft'�� tr�_��. __ - - - _ -- ------ — F��,;c'3'"y 2i'?�)J� 1�:�1L��;1? ll �O!rcff�:Ci1017 �tOr�771�i'2�Ef PO�iU�tC � F�IEL�E')t;0!i �-'t-�j � • Sediment traps may not be feasible on utilit}� projects due to the limited w•ork space or the short-term natwe of the work. Portable tanks may be used in place of sediment traps for utility projects. ;tifainte�rance • Sediment shall be removed from the trap wfien it reaches 1-foot in Standards depth. • An�� damage to the pond embankments or slopes shall be repaired. u ace area etermined 4' Min. at top of weir � � -L — — — — — — — — — — — — — � �� 1' Min. Overflow T 1'Min. j (__ "�'S� j . :': .. .'_ :: .:� :��:�c.•:�.`--:R 1'Min. �L 3.5'-5' � — - —�. - , . - ` � �� 1.5'Min. • _1_ FIBt BOttOm __1 _ RipRap '., , 5" 2"�"Rodc VJashed gravel Note: Trap may be formed by berm or by partial or complete excavation Geotexfiie Discharge to stabilized conveyance, outlet,or level spreader Figure 4.22 Cross Section of Sediment Trap --- - 6' Min. -- - � - �� _,��- - � � - ��,_�i ;��,- �j�=,��_��_ 1'Min. depth overflow spilMray -I'i_!�I ��_��- -�- - - - �- - - Native soii or � � Min. 1'depth compacted backfili � . � .-�. 2"-4", rock �.... ',j. . . ... . . . . . . . . . ._ Geotextile - . — Min. 1'depth 3/4"-1.5'. -- - _. — - " - washed gravel Figure 4.23 Sediment Trap Outlet 4104 Volume Il—Consfruction Stormwater Pollution Prevention February 200F � L' V / BMP C250: Construction Stormwater Chemical Treatment Pt�rpn.se� Turbidity is difficult to control once fine particles are suspended in stormwater runoff from a construction site. Sedimentation ponds are effective at remo��ing larger particulate matter by gravity settling, but are ineffecti��e at remo��ing smaller particulates such as clay and fine silt. S�diment ponds are typically designed to remo��e sediment no smaller than medium silt(0.02 mm). Chemica] treatment may be used to reduce the turbidity of stonn��ater runoff. Coirdr�iu,�s nf"(:�e �'hemical treatment can reliably pro��ide exceptional reductions of curbidity and associated pollutants. Very high turbidities can be reduced t�, levels comparable to u�hat is found in streams during dry weather. I�raditional BMPs used to control soil erosion and sediment loss from sites under devetopment may not be adequate to ensure compliance with the ��ater quality standard for turbidity in the receiving water. Chemical ir�atment may be required to protect strearns from the impact ofturbid �t��nn�•ater discharges, especially w�hen construction is to proceed through th� �Tet season. Formal written approval from Ecology and the Local Permitting �uthorit�• is reyuired for the use af chemical treatment regardless of site size. The intendon to use Chemical Treatment shall be indicated on the tioNce of Intent for co�•erage under the General ConstrucNon Permit. Chemical treatment s�stems should be designed as part of the Construction S�VPPP, not after the fact. Chemical treatment may be used to correct problem sites in limited circumstances with formal �ti ritten appro�al from Ecolog�� and the Local Permitting Aut6ority�. The SEPA revie�4� authority must be notified at the application phase of the project revie« (or the time that the SEPA determination on the project is performed)that chemical treatment is proposed. If it is added after this stage, an addendum«•ill be necessary� and ma} result in project approval delav. Design u,id See Appendix II-B for background information c�n chemical treatment. Ins1a/lation Specificati�f�s Criteria for Chemical Treatment Product L'se: Chemically treated stormwater discharged from construction sites must be nontoxic to aquatic organisms. The following protocol sha]1 be used to evaluate chemicals proposed for stormv��ater treatment at construction sites. Authorization to u.e a chemical in the field based on this protocol does not relieve the applicant from responsibility for meeting all discharge and receiving �ti ater criteria applicable to a site. • Treatment chemicals must be approved by EPA for potable water use. • Petroleum-hased polymers are prohibited. ___-- _ _ _-- __-- - --- -- February �C�05 Volun�e I!- Constr�c:'ron Stormwater Pcilufion Prevention 4-111 ��Z�� • ��Cll>l� l�� :iUlll��I�1L�ll.'�Il I�'�1' ti�l� L�C, )31 I��I� �Ela�� : �i�I1�U�t��, ;�' demonstrate that turbidity reduction necessary to meet the recei��n�_ ��ater criteria can be achieved. Test conditions, ir�luding but n��t limited to raw�vater quality and jar test procedur�:. should be indicative of field conditions. Although these small-scale tests ea�inc�i be expected to reproduce performance under fiel� conditions, they are indicative of treatment eapability. • Prior to authorization for field use, the chemicalh treated stormu�ater shall be tested for aquatic toxicity. Applicable pr��cedures defined in Chapter 173-205 V�'AC, Whole Effluent Toxicity 1�esting and Limits. shall be used. Testing shall use stormwater from :he construction sitr at v�•hich the treatment chemical is proposed far u�� r a «atzr solution using soil from the proposed site. • The proposed maxin�um dosage shall be at least �: tactor of ti�e lo��er than the no obsen�ed effects concentration(NOEC�. • The approval of a proposed treatment chemical sI-:all be conditional. subject to full-scale bioassay monitoring of treate4 storm��ater at the canstruction site v►�fiere the proposed treatment ch�mical is to be u�ed. • Treatment chemicals that have already passed the abo��e testing protocol do not need to be reevaluated. Contact tl�e Departmem ot Ecology Regional O�ce for a list of treatment cr:;nical� ihat ha�� been evaluated and are currently approved for use. Treatment System Design Consideradons: T`he de�:`�Z and «perati��n c�f a chemical treatment sti�stem should tal:e into consideration the factors that determine optimum, cost-effective performance. It n:a�� not be possible tc> fully incorporate all af the classic concepts into the de;ign because of practical limitations at construction sites. Nonetheles�. it is impartant t�� recognize the following: • The right chemical must be used at the right dosa=_e. A dosage that �s either too low or toc� high H�ill not produce the lo��zst turbidit��. Therc is an optimum dosage rate. This is a situation v��h�re the adage "addin�� more is always better" is not the case. • The coagulant must be mixed rapidly into the wat:r to insure prop�r dispersion. • A flocculation step is important to increase the raTe of settling, tc� produce the lou�est turbidity, and to keep the dosa�e rate as lo« as possible. • Too little energy input inta the water dwing the f':occulation pha�e results in flocs that are too sma11 and-'or ins��fficie�~tl�� dense. T�� much ener�� can rapidly destrt�� ;1�� a� it i� i�c,i,r_,i -- --- - ----- __ ---- - ___ 4-112 Volume 11— Construction Stom�water PoNution Prevention February 2005 f� � • �III�C i!7�' \1��U111C i�t l�lc Ll�jlll li ;i t�t:�'I'i1;111:3i1i lll I�li :illli�l•.172 tit �11�i'_\ per unit ��olume,the size of the ener�� input >��t�n� �an h� t��> �m:.�I relative to the volume of the basin. • Care must be taken in the design uf tl�� itl�dra��al ;}st�m t�� minu�:;i�� outflo�; velocities and to prevent floc discharge. ?he discharge sh� i�l.i be directed through a physical filter such a� a �e�_etat�d s��ale that would catch an}' unintended floc dischar�� Treatment S�'stem Design: Chemical treatm�l�t ��t�n�� llal: b� desi�ned as batch treatment sy�stems using either ponds or portable trai!�r- mounted tanks. Flo��-throu�h continuc�l:: trcatmer�t ��temc are nc�t allowed at this tim�. � chemical treatm�rn >��tClll C��ilti(�tj t�I I�1� >l�)['ll`;�i.11�l' �t��t�llt)II �\>i.'ll] (either temporary di�ersion or the permanent site drainage system►, a storage pond, pumps,a cHemical feed system, treatment cells, and interconnecting piping. The treatment system shall use a minimum of hvo lined treatment eell.. ?�lultiple treatment cells allow for clarification of treated w•ater��hile ��;h�1 cells are being filled or emptied. Treatment cells may be ponds or tan4.�. Ponds with constructed earthen embankments �reater than six feet hi�h Te(�1172e S]�Cla� �t1t?11]Z�t'lll� ;1T1:9�\tiZ>- (��I'?af?�� [311}�� I?]:3\ :li�� l�� UII:;!':: for some sites. The follo«in� �yu�pi»�nt sl�uuld br 1�>ra�.;J in an ��,�r:i[i��n� ;h�d� • the chemical injector; • secondary containtnent f�r ae�c�_ cau�tic. hufferin�� n�E��un�. ��in�i treatment chemical; � • emergency show�er aT�� e��a�l�. an�i • monitoring equipment �hich consist, ��f a }�i 3 tn�trr an� a turbidimeter. Sizing Criteria: The combination of the storage pond or other holding area and treatrnent capaciry should be lazge enough to treat storm��•ater during muitiple day storm events. It is recommended thai at a minimu»� the storage pond or other holding area should be sized to hold 1.5 time� the runoff volume of the 10-year, 24-hour storm event. Bypass should he proti�ided around tl�e chemical treatment system to accommodate extrei;�� storm events. Runoffvolwne shall be calculated using the methods presented in Volume 3, Chapter 2. If no hydrologic analysis is r�c�uired for the site, the Ratianal Method may be used. Primary settling should be encourage� in the storage pond. A foreh�� with access for maintenance may be benelicial. There are t«�o opposing consideratic�ns in �izing the treatment cells. :� lareer cell is able to treat a lar�er� ��olumr ��1��at�r ea�h timr a hat�h i� _ _ __ _ - ----- _ —_ Feb�uary 20D5 Voiume !1- Gonstructicr� Storrnv✓ater Poi;uticn Frever�ti�n �-I�� processed. Ho��e��er, the larger the cell the longer the time required to empry the cell. .� larger cell may also be less effective at flocculation and therefore require a longer settling time. The simplest approach to sizing the treatment cell is to multiply the allowable discharge flow rate times the desired draw�do«�n time. A 4-hour dra�;�dow�n time allo��s one batch per cell per 8-hour«ork period, gi��en 1 hour of flocculation follov��ed by ri��o hours of settling. The permissible discharge rate govemed by potential downstream effect can be used to calculate the recommended size of the treatment cells. The following discharge flow rate limits shall apply: • If the discharge is directly or indirectly to a stream, the discharge flow rate shall not exceed 50 percent of the peak flow rate of the 2-year, 24- hour event for all storm e�•ents up to the 10-year, 24-hour e�'ent. ' • If discharge is occurring during a storm e�ent equal to or greater than the 10-year, ?4-hour event, the allowable discharge rate is the peak flow rate of the 10-year, 24-hour event. • Discharge to a stream should not increase the stream flow rate by� more than 10 percent. • If the discharge is directly to a lake, a major receiving ��ater listed in Appendix C of Volume I, or to an infiltration system, there is no 'I discharge flow� limit. � • If the discharge is to a municipal storm drainage systern, the allow�able I discharge rate may be limited by the capacity af the public system. It � may be necessary to clean the municipal storm drainage system prior to the start of the discharge to pre�ent scouring solids from the drainage system. • Runoff rates shall be calculated using the methods presented in Volume 3, Chapter 2 for the predeveloped candition. [f no hydrologic analysis is required for the site,the Rational Method may be used. Mainte�rance '�lonitoring: The follow�ing monitoring shall be conducted. Test results Standards shall be recorded on a daily lo� kept on site: Operational Monitoring • pH, conducti��ity (as a surrogate for alkalinitJ i, turhidit� and temperature of the untreated storm�;at�r • Total volume treated and discharaed • Discharge time and flow rate • Type and amount of chemical u�ed for pH adiustment • Amount of pc�l�mer u�ed fi�r treatm�nt • S�ttlinQ tin�� _ __ __ _ — ---------- -- 4-1?4 L'olu;re i!- Cor s'ructra� Storm�,aterPoN�fion Pre�ention February 2005 , '; . r L Compliance Monitoring • pH and turbidiry of the veated stormwater • pH and turbidity af the receiving«•ater Biomonitorin� Treatzd storm«-ater shall be tested 1'or acute (lethal) toxiciry. Bic�assays shall be conducted by a laboratory aecredited by Ecology, unless other��ise appro��ed by Ecology. T6e performance standard for acute tocicih• is no statisticall�� significant difference in sun�ival ben��een the control and 100 percent chemicalh� treated stormH�ater. Acute toxicity tests shall be canducted ��ith the f�llo�ti�ing species and protocols: • Fathead minnow, Pimephales��r-omelas (96 hour static-rene��a1 test, method: EPA/600/4-90/027F). Rainbow trout, Oncorhynchus mykiss (96 hour static-renewal test, method: EPAI600i4-90/027F)may be used as a substitute for fathead minnow. • Daphnid, Ceriodaph»ia dubia, Daphnra pule.r, or Daphnia m�gna(48 hour static test, method: EPA1600f4-90/027F). , All toxicity tests shall meet quality°assurance criteria and test conditions in �, the most recent rersions of the EPA test method and Ecology Publication � # Vi�'Q-R-95-80, Laboratory Guidance and V�fiole Effluent To�:icity Test �� Revieu�Criteria. � Bioassays shall be perfonned on the first five batches and on e�e�� tenth batch thereafter, or as othervvise approved by Ecology. Failure t�meet the performance standard shall be immediately reported to Ecology. Discharge Compliance: Prior to discharge,each batc6 of treated storm�tiater must be sampled and tested for compliance H�ith pH and turbiditv limits. These limits ma� be established by the water quality standards or a site-specific dischar�e permit. Sampling and testin� for other pollutants may also be necessary at some sites. Turbidity must be within > I`TUs of the background turbidity. Background is measured in the receiving w•ater, upstream from the treatment process discharge point. pH must be«�ithin the range of 6.5 to 8.5 standard units and not cause a change in the pH of the receiving �-ater of more than 0.2 standard units. It is often possible to discharge treated stormw�ater that has a lo«�er turhidity than the receiving��ater and that matches the pH. Treated storm��ater samples and measurements shall be taken frc�m the discharge pipe or another location representative of the nature of the veated stormwater discharge. Samples used for determining complianc� �;�th th�"�ater qualit} standards in the receiving n�ater shall not he taken - ___ __ __ __ - _ _ February 20U5 Volw1�e li- ConstrZ�ciian Storrn�,�a!er Foilution Preve��fro�; 4-115 � � 1 y �I � � ti�oT�� the t3��tn�ent �?o13d �rior to d��antin��. C�ompCian�� i�h th� ��;�t��r quaiity standards is deternxined in the rei:eiving v.ater. Operator Training: Each contractor��hp intends to use chem�cal treatment �hall be trained h�� an e�perien�:ed cc�ntractor t�n an actice ,i:� for at least 40 hc�ui-�. Standard Bl�'IPs: �urtaee �tahilization E3t�fP� �}.c�Eild k�� implel��ented ��11 sit�to prevent signit3cant eros�on� All �;t�� sn311 it�e a tll�ek ��hze! ��a:1a to prevent trackine of sediment off�ite Sediment Removal And Disposal: • Sediment shall be remoti�ed from ihc stora�� c>r treatment eells as necessary. Typically, sediment rema�•al is required at Ieast once durina a��Fet season and at the decommissioning of the cells. Sediment remaining in the cells beri�-een batches may en(�a�� thr settliilQ pracess and reduce the required chemical dosage. • Sediment mav be incorporated into the site at�-ay frc�m di-��ina�ic�. _ _ _ _ _ _ -- __ ____ ----__ _ _ __ _- -----__ _ _ ___�—_____ 4-1?� Voi�ime !l- Ccnsfruct�on Stor�mwaier Poiiutrcn Preventicn February 1GC%5 , �` BMP C251: Construction Stormwater Filtration Purpose Filtration remo��es sediment from runofforiginating from disturbed areas of the site. f o�rditio�rs ��f C'ce Traditional B!�'IP� used to conirol soil erc�sion a��d sediment loss fic�m sites under de��elopment may not be adequate to ensure compliance v��ith the ��ater qualiry standard for turbidity in the recei�ing v��ater. Filtratian may be used in conjunction with gravity settling to remo��e sediment as small a� fine silt (0.5 µml. The reduction in turbidity ��ill be dependent on the particle size distribution of the sediment in the stormwater. In some circumstances, sedimentation and filtration ma�� achieve compliance N�ith the w°ater quality standard for turbidity. l:nlike chemical treatment, the use of construction stormwater filtration does not require approval from Ecology. E=i Itration may also be used in conjunction with polymer treatment in a p.1rtable system to assure capture of the flocculated solids. nesi��n uird Background Injormation I,rstallation S�ecifrcativns Filtration w�ith sand media has been used for o�•er a century to treat ��ater and wastewater. The use of sand filtration for treatment of storm�-ater has developed recently, generally to treat runoff from streets, parking lots, and residential arzas. The application of filtration to construction �torm�vater treatment is currently under development. I��o types of filtration systems may be applied tc� construction stormwater Tr�atment: rapid and slow�. Rapid sand filters are the rypical system used t��r �vater and wastewater treatment. They can achieve relati��ely high h�c�raulic flow�rat�s, on the order of? to 20 gpm:'sf, because they ha��e ,.�,tomatic backw�ash systems to remove accumulated solids. In contrast, <1�>t�� sand filters ha�-e�•ery low hydraulic rates, on the order of 0.02 ��mti'sf,because they do not ha��e backwash systems. To date, slow sand iiltratian has generally been used to treat storm«•ater. Slow sand filtration i� mechanically simple in comparison to rapid sand filtration but requires a much larger filter area. Filtration Equipment. Sand media filters are available w�ith automatic backwashing features that can filter to 50 µm particle size. Screen or bag filters can filter do�in to 5 }�m. Fiber wound filters can remove particles dov��n to 0.5 µm. Filters should be sequenced from the largest ta the smallest pore opening. Sediment removal efficiency will be related to particle size distributian in the storm�vater. Treatment Process Description. Stormwater is collected at interception point(s)on the site and is diverted to a sediment �ond or tank for removal ot�1arQe sediment and stc�rag� of the storm��ater b�fc�re it is treated h�� the I February 2005 Volume Il— Constr�;ct�cn Stormwater Pollution Preven!ion � 4-117 , , ,'' j filtration system. The stormw�ater is pumped from the trap, pond, ar tank through the filtration system in a rapid sand filtration system. Slou� sand filtration systems are designed as flo��through systems using g�ati�iry. If large volumes of concrete are being poured, pH adjustment may be necessary. .'�faintenance Rapid sand filters typically have automatic back�vash systems that are Standards trigQered by a pre-set pressure drop across the filter. If the backti��ash water volume is not large or substa.�tially more turbid than the storm�vater stored in the holding pond or tank. backwash return to the pond or tank ma� be appropriate. Hov��ever, la��d application or another means af treat�nent and disposal may be nee�ssary. • Screen, bag,and fiber filters must be cleaned andior replaced �i�hen they become clagged. • Sediment shall b� removed frcn� the storage and/or treatment ponds as necessary. Typically, sedimer.: removal is required once or tu-ice during a wet season and at the d�commissioning of the ponds. -- — --- --- _- _ ___ _ ---- - 4-118 L'olU"�E ll- Constr�ction Stormwater �;ir,�hor� Pre�e;;tror� F�;��ary 2005 �, .. Stormwater Pollution Prevention Plan Appendix C — Alternative BMPs The following includes a list of possible alternative BMPs for each of the 12 elements not , described in the main SWPPP text. This list can be referenced in the event a BMP for a speci�c element is not functioning as designed and an alternative BMP needs to be implemented. Element#1 - Mark Clearing Limits Element #2 - Establish Construction Access • Wheet Wash (BMP C106i Element#3 - Control Flow Rates Element#4 - Install Sediment Controls • Nets and Blankets (BMP C122) • Storm Drain Inlet Protection (BMP C220) Advanced BMPs: Element#5 - Stabilize Soils • Plastic Covering (BMP C123) Element#6 - Protect Slopes • Polyacrylamide for Soil Erosion Protection (BMP C126) • Interceptor Dike and Swale (BMP C200} Element #8 - Stabilize Channels and Outlets • Concrete Handling (BMP C151) • Grass-Lined Channels (BMP C201) Element#10 - Control Dewatering Additional Advanced BMPs to Control Dewatering: 31 15564 005 doc ;.` BMP C10fi: Wheel Wash Purpo�e VJheel ��ashe� r�duce the amount of sedime:.: transported ont� pa�ed , roads by moter ��ehicles. �, Condirions of L?se Vdhen a stabilized construction entrance (see BMP C105) is not pre��entin_� sediment from being tracked onto pavement. I • W'heel v��a�hing is generally an effective 3'viP«-hen installed «ith '�, careful att:ntion to topography. For exar.�ple, a ��heel wash can be � detriment�'. if installed at the top of a slor�e abutting a right-of-v��a} «fiere the��ater from the dripping truck �an run unimpeded into the street. • Pressure��a;hing combined with an adecuately sized and surfaced pad with direc; drainage to a large 10-foot x :0-foot sump can be�ery effective. De.cign a�rd Suggested details are sho�tim in Figure 4.3. T:�e Local Permitting I�r.ctallu�ion Authority ma� allow�other designs. A minir.-,um of 6 inches of asphalt Spc��•i/ic�uri��n• treated base(ATB) oti�er crushed base mater:.:l or 8 inches over a good subgrade is recommended to pa��e the w-heel �.�ash. Use a low clearance truck to test the wheel «ash before paving. Either a belly dump or :c��t-boy will work w•ell to test �learance. Keep the water le��el from 12 to 14 inches deep to avoid damage to truck hubs and fillir� the truck tongues w•ith v►�ate:-. '�4idpoint spra� nozzles are only needed in e�trernely muddy conditions. �'�heel wash s��tems should be designed w�it�i a small grade change, 6 to 1? inches for c_ !0-foot-��ide pond, to allow >.diment to flow�to the low �ide af pond tc� help prevent re-suspension o?�edirnent. A drainpipe with a �- to 3-foot�-iser should be installed on the i��v side of the pond ta allow t�c�r easy clean:.�g and refilling. Polymers m.:�� be used to promote �uagulation a�:� flocculation in a closed-loo} ��stem. Polyacrylamide i P-�'_VI)added ��the w-heel wash water at a r�te of 025 - 0.5 pounds per I.U00 gallons,�f��ater increases effectiti-eness and reduces cleanup time. If P:�M is already being used for dust or ero�ion control and is being applied by a�ater truck, the same truck can :�e used to change the wash water. lfui►ue,iance The w•heel wa�h should start out the day wit`� fresh water. Sraridard.s The wash��at�r should be changed a minim::m of once per day. On large earthworh jobs«-here more than 10-2G Irucks per how are expected, the��ash water will need to be cha:�ged more often. ��heel wash o,-tire bath wastew•ater shall be 3ischarged to a separate on- �ite treatment ��stem, such as closed-loop recirculation or land a�plication,or to the sanitary sewer with prc,�er local sewer disttict appro�•al. — -_ _ ---- -- - 4-10 Vofume 1(- Co: :��icf.�on Stormwafer Po1luUon F -,�entior February 200� �,�Z A � "Schedule 40 1 Y2"schedule=�for sprayers ,.. II 2°/6 5:1 5:1 I 1 2% Slope Slope Slope Slope II 1�1 II SIApe Wheel Wash Plan �13�15 20' 1S 50'—� Elevation View Water level �� 1:1 Slope � �1� Section A-R N.T.S. Figure 4.3 Wheel Wash Notes: 1. Asphalt construction en[rance 6 in.asphalt treated base (ATB). 2. 3-inch trash pump with floats on the sucti�n hose. 3. Midpoint spray noules, if needed. 4. 6-inch sewer pipe with butterfly vafves. Bottom one is a drain. Locate t�p pip= � I^'J8r? 1 fGCi above bottom of wheel wash. 5. 8 foot x 8 foct sump with 5 feet of catch. Build so can be clearec �,vith trackhc 6. Asphalt curb on the low road s�de to direct wa*e� back to pond 7. 6-inch sleeve under road. 8. Ball valves. 9. 15 foot. ATE �pron to protect ground from sG osh�ng water. February 2005 Vo/ume i!- Construcdon Sto-^�v.�ater Pe!lutior, Frevention 4-11 , ,„ � ,. 1 � � BMP C122: Nets and Blankets Purpose Erosion control nets and blankets are intended to prevent eros:on and hold seed and mulch in place on steep slopes and in channels so that t�egetation can become well established. In addition, some nets and blan}:�ts can be used to permanently reinforce turf ta protect drainage ways during high flovcs. Nets(commonly called matting) are strands of materia: �voven into an ogen,but high-tensile strength net (for example, coconut firer matting). Blankets are strands of material that are not tightly u-o��en, but ;nstead form a layer of interlocking fibers, typically held together by a biodegradable or phototlegradable netting (for example, excel�ic�r or straw� blankets). They generally have lo�ti�er tensile strength than nets. but cover the ground more completely. C�ir(coconut fiber) fabric comes as both nets and blankets. Conditions of L'se ET-osion control nets and blankets should be used: • To aid permanent vegetated stabilization of slopes 2H:1 V �_�r greater and with more than 10 feet of��ertical relief. • For drainage ditches and sv►�ales(highly recommended). The application of appropriate nettin�or blanket to drainage di��hes and su•ales can proteet bare soil from channelized runoff w�hile �egetation is established. Nets and blankets also can capture a great deal of sediment due to their open, porous structure. Synthetic nets and blankets can be used to perrnanently stabilize channels anc may� provide a cost-effective, em ironmentally preferable alternati�-e to riprap. 100 percent synthetic blankets manufactured for use in ditches may be easily reused as temporary ditch liners. Disadvantages of blankets include: • Surface preparation required: • On slopes steeper than 2.5:l, blanket installers rnay need t��be roped and harnessed for safety; • They cost at least �4,000-6,000 per acre installed. Ad�-antages of blankets include: • Can be installed without mobilizing special equipment; • Can be installed by anyone«ith minimal training; • Can be instailed in stages or phases as the project progresses; • Seed and fertilizer can be hand-placed by the installers as t'Ic}� '�� progress down the slope; • Can be installed in any weather; • There are numerous types of blanl:ets that can be designeci ��ith ��arious parameters in mind. Those parameters include: fiber blen�l. i mesh strength, l�ngevity, bir��eeradahilitv, cost, and a��ail•r.hilit� � --- ---- - __ - -— _ _ 4-22 V� ;:,�e �l- Consfruction Sformwat�r Poilu!ron Prevenhon �=urua;y 2005 , ., "'� Dr�r�ri und • �ee Fi�_�ure �.-3 and F��_ur� �.� t`or t��}�ical orientat��n and in�tallati��n uf Insra/lation blankets used in channels and as slope protection. Note: these are Sl�ccijicati�n.c n pical only; all blankets must be installed per manufacturer's il�stallation instructions. • 1 n�tallation is crirical to the effecti��eness of these products. If good t�round contact is not achieved, runoff can concentrate under the product, resulting in significant erosion. • 1 n�tallation of Blankets on Slopes: i Complete final grade and track�-alk up and dow-n the slope. � Install hydromulch ��ith seed and fertilizer. ;. Dig a small trench, approximately 12 inches wide by 6 inches deep along the top of the slope. � Install the leading ed�e of the blanket into the small trench and staple approximately e��ery• 18 inches. NOTE: Staples are metal,"U"-shaped, and a minimum of 6 inches long. Longer staples are used in sandy soils. Biodegradable stakes are also a�ailable. �. Roll the blanl:et slowly dow�n the slope as installer w•alks hackwards. NOTE: The blanket rests against the instal]er's legs. Staples are installed as the blanket is unrolled. It is critical that the ��roper staple pattern is used for the blanket being installed. The hlanket is not to be allo«�ed to roll do�;�n the slope on its ou�n as this stretches the blanket making it impossible to maintain soil ��ntact. In addition, no one is allowed to w�alk on the blanket after �r i� in place. � I f the blanket is not long enaugh to cover the entire slope length, ih� trailing edge of the upper btanket should overlap the leading ��i�e of the lou�er bianket and be stapled. On steeper slopes, this .»erlap should be installed in a small trench, stapled, and co��ered ti��ith soil. • �'�ith the variety of products available, it is impossible to co��er all the details of appropriate use and installation. Therefore, it is critical that che design engineer consults the manufacturer`s information and that a site visit takes place in order to insure that the product specified is a�propriate. Information is also available at the follov��ing web sites: l. ��l�S[�OT: hitp::��}�ti.��sdot.�t�a.�� eescen�ironmental;' '. T�xas Transportati�n Institute: hrtp:�lv��i�.dot.state.t�c.us;insdtdot;'orEcharVcmd�'erosionlcontents. htm ----- _ --- ---- -- --- --- - - - -_ -- - -- — --_ Fe:�-uary 2C05 Vo?ume !I- Coi;sfruction Stormwater Po!lution P!eventior-, 4-23 ? �� • Jute �t�attine«�ust t�e ��ed in conjun4tion ��ith i��ulch (B'�9P C1_'1). Excelsior, u-oven stra�� blankets and coir(coconut fib�r) blankets ma� be ins[alled��-ithout mulch. There are man}� other types of�rosie�n control nets and blankets on the market that may be appropriate in c�rtain circumstances. • In general, most nets (e.g.,jute matting)require mulch in order �u prevent erosion becausc they ha��e a fairly open structure. Bla��kers typicall} do not require mulch because they usually provide complete protection of the surface. • Extremely steep, unstable, «•et, or rocky slc�pes are often appropriat� candidates for use of s��nthetic blanl:ets, as are rn•ert�anl:s, beaches a�� other high-energy enviranments. ]f synthetic blaril:ets are used, the soil sh�uld be hydromulched first. • 100 percent biodegradable blankets are a��ailable for use in sensiti�� area�. The�e arganie hlankets are usually held together u�ith a pap�r ��t� fiber mesh and stitchin� ��hich may last up to a year. • Most netting used with blankets is photodegradable, meaning tht� break doti��n under suniiaht(not UV stabilized}. No�r•e��er, this procz:� can take months or years ev�n under bright sun. Once��egetation i� established, suniight dc�es not reach the mesh. It is not uncommon t�5 find non-degraded netting stilt in place several }=ears after installati��i. This can be a problem if maintenance requires the use of mow�zrs or ditch cleanine equipm�nt. In addition, birds and small aniinals c�n become trapped in the netting. Maintenance • Good contact with the 4Tround must be maintained, aild erc��ion mu�t Standards �Qt accur beneath the net or blanket. • �n�a� areas of the n�t c�r blanket that are dama�ed or n�,t in �l��se cc�ntact «-ith the ground shall b� repaired and stapled. • If erosion occurs d�e tc� poorl}� controlled draina�re, t?�t ��rol�i�n� shall he fixe� and the erode�� area pr��t�ct�d. ---- -- _ _ ____ — ----- -__ _ ---- ---- -- 4-24 L'alume /t— Cof�strucl�on Stc��hate,rPoilufron Preventron February 20�5 //�i��' .i . �-._. .___... - i � �: � �,_. ;� \�� -� � �\�/�� .\ �� ' f �� /i�/ �� . .-�\� v q0�w ` \, / '/.,.\ ..�� A.. ..� \�I�\%� ti� ,\� \� `� �\\\': �/ �;, r /i . �t\ �\ti�'4''��'��\\..��\�� \�cH lt'� �POld.nd ✓ '�� i �' �L� La+QiWdY�r AnGwr TeMiC� T�rmirrl Sbp!and ChrnN Mdwr Tnnch �� +1, .r �` � � � + '`�1� ,_� � � �� '�_ - �,,,� �� ' � �: �` s�.d r-� - _ +k � .,�. r.,sm�.,�.�.. � ,- _ � r _ ;<� �, �� , � �.,� �. /��"'� �� ! y r � �,�- �' �l' �. ��'�� "%f/ �--"�- ;i;',\ P\ r� `/`f j \ �: ��:�� i � �` �� ` , , � :_ �r- cn.a�.wr u zs ,�+,.�w.i. '��, '��' IsO1T1Bt1'�C VIBW p� �/ ��` \;\�i�\l` . __ __ , � � �/. � �;� � -�;:+a�..� ti < . � ,r �: ^ � � . r.x�uu � ' .� �- �",�� y � � ,l . `� �-<'�'.�• •\�/��/j /r��Y'f�/� �� . ,��v `�C.�\�/�\' ii�e""1 �j��, � ./. Inital ChamN Aricnor Tqr�di t�rnfitlwR ChKic Sbt tiOTES: 1 CTeck slots b bc oauvucad pc rosn6wuets�pedficati0as. 2.Sn17n��stsplm�4yout pa murefacturas�paificMiom- Figure 4.4— Channel Installation Slope surface shai be smootn�efo•e pWcement for proper soii contact 1!there�s a berm at the Staplinp pattem as per tcp of s,ope anchor manufacturer's recommendatlons. ' -- upsiope ct!tie cer� � - �•�y Min 2' � �' Overlap � i � � Anchor in 6'x6"min Tren� � i and stapk at 12" mtervais i �� Min 6'overiap /� � � Stap�e overl�ps ' � ' ' max 5"spapny. Br�ng material down to a kve!area,turn Do rat stretch Wankets<<namngs t�ght- the entl under 4"and stapk af 12"irkenals. adow the rods to mold to any irropWarrties. for sbpea bss than 3H 1V,rolls Lime,Aertitize.and seed betore instaNation_ may be placed in ho�zon;ai stnps Planung of shiubs,Vees etc Should occur atler installation Figure 4.5—Slope Installation February 2005 Volume ll—Construction Sformwater Pollution Prevention 4-25 , f � BMP C123: Plastic Covering Purpose Plastic covering pro��ides immediate, short-term erosion protection to slopes and disturbed areas. Conditions of• Plastic covering may be used on disturbed areas that require corer L'se measures for less than 30 days, except as stated below. • Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note: The relatively rapid breakdo��n of most polyethylene sheeting makes it unsuitable for long-term (greater than six months) applications. • Clear plastic sheeting can be used over new•ly-�eeded areas to create a greenhouse effect and encourage grass grov►th if the hydroseed was installed too late in the season to establish 75 percent grass cover, or if the wet season started earlier than normal. Clear plastic should not be used for this puri�ose during the summer months because the resulting high temperatures can kill the grass. • Due to rapid runoff caused by plastic sheeting, this method shall not be used upslope of areas that might be adversely i�npacted by concentrated runoff. Such areas include steep and/or unstable slopes. • VVhile plastic is inexpensive to purchase, the added cost of installation, maintenance,removal, and disposal make this an expensive material, up to �1.50-2.00 per square yard. • Vvhenever plastic is used to protect slopes, ��ater collection measures must be installed at the base of the slope. These measures include plastic-co��ered benns, channels, and pipes used to covey clean rainwater away from bare soil and disturbed areas. At no time is clean runoff from a plastic covered slope to be mixed ��-ith dirty runoff from a project. • Other uses for plastic include: 1. Temporary ditch liner; 2. Pond liner in temporary sediment pond; 3. Liner for benned temporary fuel storage area if plastic is not reactive to the rype of fuel being stored; 4. Emergency slope protection during heatiy rains; and, 5. Temporary drainpipe("elephant trunk")used to direct �;�ater. 426 Volume Il- Consbuctron Stormwater Pollution Prevention February 2005 Design and • Plast�c slope co��er must b: installed as tollo��s: Insta/lation �. Run plastic up and do»�n slope, not across slope; Specifications 2. Plastic may be install��j ��rpendicular±�� a sl��pe if the �lop� lenath is less than l0 feet: 3. Minimum of 8-inch o��rlap at seam�: 4. On long or w�de slopes, or slopes suhj��t t�� ti��nd. all ��am> �h��t�l� be taped; 5. Place plastic into a small (1?-inch ��ide r�� 6-��nh de�pj sl�t trer�ch at the top of the slope ::nd backfiil ��ith �oil to keep ��ater from flowing underneath; 6. Piace sand filled burla:� c�r ��eot�stile ha�� e�er� � t�� tc�t alun<7 Se3111� �:iiij ��llll�� ;3 \\t ��.t'il >l�i�t' �ilrt�l'c��l �;ii�l ii� fll''''.1 l�1CIli ?tl ` pla��: 7. Insp�ct �la�t�� for i-i}?�. «ar,, an�i upcT� ��uil�, =<<�ul�s!I� .ind r��air immediately. This pre��ents high velocit�� runui-t frun� ��a�nns bare soil which causes extreme erosion; 8. Sandbags may be lowered into place tied tu rop�• F3��r. all sandbags must be staked in place. • Plastic sheeting shall have a minimum thickness oi 0.06 millim�t�rs • If erosion at the toe of a slope is likely, a gravel berm, riprap, or oth�r suitable protection shall be �r�ta!led at the tt�c i�f tt�e �Ir�� n �,rder ir� reduce the velocity of run��t'. �laintenance • Torn sheets must be replac��i an�3 ��pen s�all�, r��a i r��i Standards • If the plastic begins to deteriorate due tu ultra�«�let rad�ai��,i�, it mu�t be completely removed and replaced. • When the plastic is no lon�er need�d. it �halt ��c ec�m}�letel� reTi��d_ • Dispose of old tires appro�riatel�. February 2005 Volume N—Construction Stormwater Pollution Prevention 4-27 �� BMP C126: Polyacrylamide for Soil Erosion Protection Purpose Polyacrylamide(PAM) is used on construction sites to prevent soil erosion. Applying PAM to bare soil in advance of a rain e��ent significantly reduces erosion and controls sediment in two ways. First, PAM increases the soil's available pore ��olume,thus increasing intiltration through flocculation and reducing the quantiry of storm��ater runoff. Second, it increases flocculation of suspended particles and aids in their deposition, thus reducing stonnwater runoff turbidiry and iinpro��ing water qualiry. Conditions of L se PAM shall not be directly applied to water or allow�ed to enter a water body. In areas that drain to a sediment pond, PAM can be applied to bare soil under the followin� conditions: • During rough grading operations. • Staging areas. • Balanced cut and fill earthwork. • Haul roads prior to placement of crushed rock surfacing. • Compacted soil roadbase. • Stockpiles. • After final grade and before paving or fmal seeding and planting. • Pit sites. • Sites having a w�inter shut down. In the case of w•inter shut dow�n, or ��here soil w�ll remain unworked for several months, PAM should be u�rd together��•ith mulch. De.�rgn u�rci �' �� may be applied in dissolved form w•ith water, or it may be applied in Insra/lation dcy, granular or po��dered form. The preferred application method is the , dissolved form. ' .Spr�•i f cntro►ts ', PAM is to be applied at a maximum rate of 2/3 pound PAM per 1000 '�� ;allons water(80 mg/L)per l acre of bare soil. Tahle 4.8 can be used to 'I determine the PA�'I and water application rate for a disturbed soil area. Higher concentrations of PAM do not provide any additional effectiveness. Table 4.8 PAM and Water A lication Rates Disturbed Area ac PA�1 lbs) R'ater al 0.50 0.�: �00 I.00 0.66 1,000 � 1.50 1.00 1.500 ; 2.00 1.32 2,000 2.50 1.65 2,500 3.00 2.00 3,000 3.50 233 3,500 4.00 2.65 4,000 4.50 3.00 4,500 �.00 �.0�0 —_ _ _ _ _ --_ _ - - _ --- _ _ _ __ - -- - - — --- _ 4-32 Volume 11— Constr;;ction Stormwater Pollutron Prever%!ion February 2005 �' 1� i The Preferred Method: • Pre-measure the area w�here PAM is to be applied and calculate the amount of product and water necessary to provide coverage at the specified application rate (2/3 pound PA!N/1000 gallons/acre). • PAM has infinite solubility in water, but dissolves very slowly. Dissolve pre-measured dry granular PAM w�th a known quantin�of clean v��ater in a bucket several hours or overnight. Mechanical mixing v��ill help dissolve the PAM. Alw�ays add PAM to water-not w-ater to PAM. • Pre-fili the water truck about 1/8 full with wrater. The water does not ha��e to be potable, but it must ha�e relati��ely low turbidiry— in the range of 20 NTU or less. • Add PAM iWater mixture to the truck • Completely fill the water truck to specified volume. • �pray PA1WWater mixture onto dry soi) until the soil surface is uniformly and completely wetted. .1n .�Iternate Method: P �'vi may also be applied as a po«�d�r at the rate of 5 lbs. per acre. This �nust be applied on a day that is dry. For areas less than 5-10 acres, a hand-held"organ grinder' fertilizer spreader set to the smallest setting will ��ork. Tractor-mounted spreaders will «�ork for lazger areas. Tl�e following shall be used for application of PAM: • P:'�'�'I shall be used in conjunction w7th other BMPs and not in place of ��ther BMPs. • [�o not use PAM on a slope that flow�s directly into a stream or ��etland. The stormw�ater runoff shall pass through a sediment control 13\1P prior to discharging to surface waters. • 1)o not add PAM to water discharging from site. • ��'hen the total drainage area is greater than or equal to 5 acres, PAM tr�ated areas shall drain to a sediment pond. • :�reas less than 5 acres shall drain to sediment control BMPs, such as a minimum of 3 check dams per acre. The total number of check dams tised shall be ma�cimized to achieve the greatest amount of settleinent ��f sediment prior to discharging from the site. Each check dam shall he spaced evenly in the drainage channel through which storm�ater tlo��s are discharged off=site. • �>n all sites,the use of silt fence shall be maximized to limit the ��ischarges of sediment from the site. • .111 areas not being actively �orked shall be covered and protected t'rom rainfall. PAM shall not be the only cover BMP used. February 2005 Volume ll- Construction Stormwater Pollution Prevention 4-33 �� • P.��1 can be a lied to ��et soil, but dl-ti �oi1 i; �refi;rred due to less �� PP . F sediment loss. • PAM will vti�ork��hen applied to �atur.:;�d ��ii l�ut i� n�,t a; �tt��ti�e a: , applications to dry or damp sail. • Keep the granular PAM suppl} �ut of:hz �un Granular P.a�9 lo;es ii; effectiveness in three months after exposure to sunlight and air. • Proper application and re-application plans are necessary to ensure total effectiveness of PA�v1 usage. • PAM, combined with «•ater, is very slippery and can be a safen hazard. Care must be taken to prevent spills of PAM po�vder ont�, paved surfaces. During an application of PA?�4, pre��ent over-spra� from reaching pavement as pa��ement �ti-ill become slippery. If PA�1 powder gets on skin or clothing, wipe it offv��ith a rough towel rath�r than ��a�l��i�� iti� ��a:er-thi� c�n1�� ma?�..� cleanup �I�es�ier and tak� lan��r. • Som� P_�'�l> arc mc?r� tasic and �arrn:..;�,�ilic tl�an �ithcr;. (?nl� tll� most en�ironmentally safe PA'�i products should be used The specific PAM copolymer formulat;on must be anioni�. C�tioni� PA:�'I shall not be used in any application because of kno�t�n aquatic toxicity problems. Only the (zighest drinking water grad� PA'�1, certified for compliance �}-ith AtiSIiIvSF Standard 60 for drinking «-ater treatment, ��•ill be used for soil applications. Recent media attention and high interest in P��1 has resulted in some entrepreneurial exploitation of the tern� "poly7ner." All PAM are polymers, but not all polymers are PA�1, and not all PAM products comply«�ith ANSI/NSF Standard 60. FAiVI use shall be reviewed a��d approved by the local �rmitting auth�rit_y. The Washington State Department of Transportation(WSDOT) has listed approved P:'��1 products on their web page. • PA'v1 designated for these uses should be "water sotuble" or "lin�ar" ;�� "non-crosslinked". Cross-linked or water absorbent PA�VI, polymerized in highly acidic (pH<2)c�mditions, are used to maintai�� soil moisture content. • The PA.h'i anionic charge densiiy may �-ary from 2-30 percent; a �alu� of 18 percent is typical. Studies conducted by the United States Deparcment of Agriculture(USDA).%ARS demonstrated that soil stabilization was optimized by using�ery high molecular weight (1�- 15 mg/mole), highly anionic (>20% ht drolysis) PA.TvI. • PA.�vi tackifiers are available and bein� used in place of guar and alpha plantago. Typically, PAM tackifiers should be used at a rate of no more than 0.5-1 Ib. per 1000 gallons of water in a hydromulch ma�hinr. S��i�ir tsickiticr ��rc�d�ict instr:.:tiun� tia� t�, use at a rat� c�l�� — - -- ------- — _ __ --- __ 4-34 Vo.ume f! Cor�siructton Stor,nwater Pollutioi� rreventfon February 2t,�v� ��,�- �__ � lb;. ��zr acre. ��hi�h can he tc�o much. In ad�it;�,n. �,uinE, �,r:,l�irm; can occur at higher rates due to increased viscosin�. Mainten4nce • PA'Vf may be reapplied on actively w•orked areas alter a-38-h�ui Standards period. • Reapplication is not required unless PAM treated soil is disturbed or uniess turbidity levels show the need for an additional application. If PAM treated soil is left undisturbed a reapplication may be necessan afrer tvvo months. More PAM applications ma�� be required for steep slopes, silry and clayey soils(USDA Classification Type "C" and "I)" soils), long grades, and high precipitation areas. When PA�1 i� applied first to bare soil and then covered ��itl; �tra��, a reapplicati��n may not be necessary for several months. • Loss of sediment and PA'�1 ma}� be a basis for E�enaltie� per RC�I' 90.�8.080. _ — — — ------ __ -- — - February 2005 Volume ll—Construction Stormwater Pollution Prevenrion 4-35 �t i' , � _ � ; BMP C151: Concrete Handling Purpose Conerete w�ork can generate prc��ess ��ater and slurry that co�ltain iin,� particles and high pH, both of tihich can ��iolate water qualiry ;tandarei� in the recei��ing u=ater. This BMP is intended to minimize and eliminate concrete process water and slurry from entering waters of the �tate. Conditions of L'se Any time concrete is used, these management practices shall bz utilized. Conerete con�tructi�n projects incluc�e. hut are not limited t�. �h� follo«�in�: • Gurbs • Side��alk� • Road; • Bridges • Foundation� • Floc�r� • Rum�a�� Design and • Concretz truck chutes, pumps, and internals �hall be «ash�d ��ut oni� Installation into formed areas awaiting installation of concrete or asphalt. Specifrcations Lnused concrete remaining in the truck and pump shall be retumed t�� • the originating bateh plant for recycling. • Hand tools including, but not limited to, screeds, shovels, rakes, 11oat�. and trow�els shall be washed off only into fonned areas a��aiting installation of concrete or asphalt. • Equipment that cannot be easily moved, such as concrete�a�er<. :h,�l l only be washed in areas that do not directly drain to natural ��:- constructed stormwater conveyances. • VVashdown from areas such as concrete aggregate drivewa�s �hall �l��t drain directly to natural or constructed stormwater com�eyances. • 1�4'hen no formed areas are available, w�ashwater and lefto��er pr��du�t shall be contained in a lined container. Contained concrete shall be disposed of in a manner that does not violate groundw-ater ��r:urface water quality standards. � Mainteaance Containers shall be checked for h��lts in the Imer dail�� urin� ��r�crete Stairdard.c p��t�r� and repaired th� ;ame da�. - -- _-- ---- - —--_ _ - --- -- February 2005 Vc?!,r??e ,'l- Cor,structron Stornzwa�er Po;;utior �revenfian 4-43 � � Yj. 4.2 Runoff Conveyance and Treatment BMPs BMP C200: Interceptor Dike and Swale Purpose Provide a ridge of con�E�a�t�c� �uiL or a rid�� ith an u}��lop� ;��al�, at th� top or base of a disturbed slope or along the perimeter of a disturbed construction area to com�ey stormwater. Use the dike and/or swale t�� intercept the runoff from unprotected areas and direct it to areas wherc erosion can be controlled. This can prevent storm runof�'from entering tl�.c v��ork area or sediment-laden runoff from leaving the construction site. Conditions oJ t'se VVhere the runoff from an exposed site or disturbed slope must be com e�r�i to an erosion control facilit�� hich can safely convey the stormwater. • Locate upslopc l�� :: �i��1�I1"ll��liiT? �11t t�� fC\�Ilt ":'!i�tf `;i'�.�1�1 l'111C''..i= disturbed area. • When placed h��l�: ,�, t:�;;�, :��r��,. .� ,ii�r,,;h�,i ,I,�� .. �t ,�•.iu.�, ih�� amount and velocit� of runotl�tlo��ing do��n the�lope. • Locate do��nslope to collect runof�from a di:?�.�rh�d arra an�i �iirr�t it to a sediment basin. Design and • Dike and/or swale and channel must be stabili�:��i ��t}� renip�,r,zr� ,�r Installation permanent vegetation or other channel protection during constructiun Specifrcations . Channel requires a positive grade f�r draina<�e: �T�eper <=rade: re�liir� channel protection and check dam�. • Review construction for areas v��her� .��nc�ppin� n�ati ��ur. • Can be used at top of new fill before vegetation is established • May be used as a permanent diversion channel to ��am th� run��ff. • Sub-basin tributary area should be one acre or less. • Design capacity for the peak flow from a 10-year, '-�-hour stonn, assuming a Type lA rainfall distribution, for temporary facilities Alternatively, use 1.6 times the 10-year, 1-hour flow indicated b� an approved continuous runoff model. For facilities that will also ser�e on a permanent basis, consult the local go�•emment's drainage requirements. Interceptor dikes shall meet the follo��ing criteria: Top t�'idth 2 feet minimum. Height 1.5 feet minimum on bern�. Side Slope 2:1 or flatter. Grade Depends on topography, howe�er, dikc s}�stem minimum i� 0.5%, maximum is 1%. Compaction Minimum of 90 percent .ASTM D698 standard proctnr. Februar� 2G05 Volume I!- Gonstructia� Storrmvater Poilc�tron Preverltior; 4-5' � , �'.��1"iZ��tlt3� \��ti�l]]�.'_ i�f �Ilt�i�:��l�_�rC ��i�t�� Average Slope Slope Percent Flo�ipath Length 20H:1 V or less 3-5% 300 feet (10 to 20)H:1 V 5-10% 200 feet (4 to 10)H:l V 10-25% 100 fe�t (2 to 4)H:1V 25-50°%� �0 fe�c Stabilization depends on velocity and reach ' Slopes <5°/a Seed and mulch applied ��ith�n � da�� c�f�iil.� construction{see B�1P C121, :tluld�rng}. Slopes 5-40% Dependent on runoff velocities and dike materials. Stabilization should be done immediatel�� using either sod or riprap or ot6er measures to avoid erosion. • The upslope side of the dike shall provide positive drainage to the dike outlet. No erosian shall occur at the outlet. Pravide energy dissipation measures as necessary. Sediment-laden runot�must be released through a sediment trapping facility. • h4inimize construction iraffic over temporan dikes. L s� temporan cross culverts for channel crossine. Interceptor swales shall meet the follo��ing critzria: Bottom W'idth 2 feet minimum: the bottom �hall b� (e��l. Depth 1-foat minimum. Side Slope 2:1 or flatter. Grade Maximum � perceni, ��th positi�z draina�e to a suitable outlet(such as a sediment pond j. Stabilization Seed as per B:1�fP C720, Temporon•and P��rm�l,r�+;� Seec�ing,or B:'lfP C202, Channel Lining, I? inches thick of riprap pressed into the bank and extendin� at least 8 inches vertical from the bottom. • ]nspect diversion dikes and interceptor swales once a��eek and at'ter every rainfalL Immediately remove sediment from the flow arra • Damage caused by construction traffic or other acti��it� �nt»t l�� repaired before the end of each working day. Check outlets and make timely repairs as needed to avoid gully fc�rmatir�n. \�h�r; the area belov��the temporary diversion dike is permanentiv stabilize�i. r�m.�� th� <iik� .::�;� till and ;tabili�e the rhannzl t�� blr:nd �+�th the naTural sl�sl�i�:�e. _ __ _-- - - —— ---_ ___ - ---- 4-5b Volume ll- Corzstructron Storn�water Po(lut�on Prevention February 20G5 �_J_ BMP C201: Grass-Lined Channels Purpose �Tu pro�ide a char�nel «ith a �egetati�e linin�_ ti�r come}'ance of� runc�ff: See Figure�.7 for typical grass-lined channels� Conditions of G'se This practice applies to construction sites where concentrated runoff need� to be contained to prevent erosion or flooding. • t�'hen a ��egetative lining can pro��ide suf�icient stability for the channel cross secrion and at lou�er��elocitie� of water(normall} dependent on grade). This means that the channel slopes are generall� less than � percent and space is a��ailable fi�r a i-elati�ely large cross section. • Typical uses include roadside ditches, char.::els at propem� boundaries. outlets for di�ersions, and other channels and drainage ditches in lo�� areas. • Channels that��ill be vegetated should be installed before major earthwork and hydroseeded with a bonded fiber matrix (BFM). The vegetation should be w�ell established(i.e., -5 percent cover)before ti��ater is alloti•ed to flow° in the ditch. VVith channels that will have high flow�s, erosion control blankets should be installed over the hydroseed. If�egetation cannot be established from seed before ��ater is allo��-ed in the ditch, sod should be instal!.d in the bott��m ��f the ditch in lieu of hydromulch and blankets. Design and Locate the channel where it can conform to th� topography and other Insta/lation features such as roads. Specifications Locate them to use natural drainage systems to the greatest extent • possible. • Avoid sharp changes in alignment or bends and chan�es in grade. • Do not reshape the landscape to fit the drai�iage channel ' • The m�imwn design �elociry shall be based on soil c�>ndit�ca��s, r�}?e of�•egetation, and method of revegetarion, but at no times shall velocity exceed 5 feevsecond. The channel shall not be overtopped h. the peak runoff from a l 0-year, 24-how storn�, assuming a Type l.a rainfall distribution." Alternati��ely, use l.6 times the 10-year, 1-hour flow indicated by an approved continuous runoffmodel to deterniin� � flow rate v��hich the channel must contain. • V�'here the grass-lined channel w�ill also function as a permanent stormw-ater con��eyance facility, consultant the drainage conveyan�� requirements of the local government with jurisdiction. • An established grass or vegetated lining is i-equired before the cha��.: can be used to com�ey starm��ater, unless stabilized��ith nets or l�lankets. --- -- -- -- _ _ _ --- -- February 20G5 Volume !I— Construction Stom�water Pollution Pre�-�niion 4-�9 � . • �i �t�i�.'_Il AC�U�Il� ��1 :t ��l',llili.i FC` 1�� A�'_�j,1l�C{ l�- _ ��IIIL' l'SCCi�� , ft%sec,a temporan channel liner is required. Ge��textile or special �� mulch protection such as fiberglass roving or stra��and netting �r��,�i� stabiliry until the��eeetation is fully established. See Figure 4.9. • Check dams shall re removed «�hen the grass has matured suffi�i�>>i!� to protect the ditch or s��ale unless the slope of the s��ale is greater than 4 percent. The area beneath the check dam� shall be seeded an�i mulched immediately after dam removal. • If��egetation is established by sodding,the pem.issible velocity for established vegetation may be used and no temporary liner is neede�i. • Do not subject gra>s-lined channel to sedimenta;ion from dist��rhed areas. Use sediment-trapping BMPs upstream o.'the channel. . V-shaped grass channels generally apply w•hert the quantit} <�f�ti.;t�r is small, such as in short reaches along roadside>. Tlie V-shaped cro�� section is least de�irable because it is difficult tc� stabilize the bottom r��here velocities may be high. • Trapezoidal grass channels are used wfiere ninoffvolumes are lar�: �I and slope is low• so that velocities are nonerosi��e to��egetated linin�i� I ('�ote: it is difficult to construct small parabolic ahaped channels.) • Subsurface drainage, or riprap channel bottoms, :nay be necessary ��n sites that are subject to prolonged wet condition� due to long durati��n flows or a high ��ater table. • Provide outlet prc�tection at culvert ends and at c:�annel interseetions. • Grass channels, at a minimum, should carry' pean runoff for ten�p��rar� construction drainage facilities fram the 10-ti�ear. _'4-hour storm without eroding. ��'here flood hazard exists, inc�tase the capac.it� according to the p��tential damage. • Grassed channel s�de slopes generally are constnicted 3:1 or flatter ic� aid in the establisl-.ment of��egetation and for m�intenance. • Construct channe:� a minimum of 0.2 foot larger around the periph�r� � to allow for soil hu;king during seedbed prepara:ions and sod buildup .1'aintenance During the establishn;��it reri�,d, check grass-lined .�7annels after e�er� Standards rainfall. • After ��i-as, is e�ta��li,hed. periuuieall�� heck thr ;hannel. c}�ecl: it att�i- every hea��y rainfall event. Immediately make rtipairs • It is particularly ii�lportant to check the chann�l ��:�utlet anci all road crossings for bank stability and evidence of pipi-.g or scour ht�l��. • Remove all significant sediment accumulations t�maintain the designed carrying capacity. Keep the grass in a �iealthy, vigor;�<<� eonditi�n ��t ,�1) tir•c,. �ince it i� tli� �riman� ert�- ��i, �,r�,teeti��r. t��r tJlr channel. ----- _ --_ _ -- —_____ _ 4-60 Volume U- Constructio�, Siormwater Pollution Preventia February 2005 , � ` Typical V-Shaped Channel Cross-section � �,.= ;;. , ;�,. '� ,� ,,`� f � ,� a ,j'�;,; � ,,..,� /� ,\\�., ,,, .�� \�f,.� '��i� '�',,,;, ,v ��1�� '%�\/� �/ �: .�. , t/ [ �\! . , I�t`'� \\ .t � n �i-,. t` �� j�� ,. - ��w �. Fiiter r " �\�'\ (150-225mm) —� -� ��'\�f�` Key in Fabric Fabric j � Grass-Lined � �— With Rock Center Typical Parabolic Channel Cross-Section :� Y �.�y: „/. � ''r,�,�a/.,� ' ,r ;;i . � � (, _ 1\ \J/�� \/�`+ •�� . ,�� . I \ .f .'I_;.�'Syr,��y / ��_pw� �'S"� j\�- �� \ VA \ �'� \ �'�� (150-225mm) �� i�� Key In Fabric �"','- %,/i �Filter ., . ` \.�. , Fabric - With Channel Liner �With Rock Center for Base Flow Typical Trapezoidal Channel Cross-Section i � � �% �--�� -- Design Depth �-�- '��, , ` �: �, �� ,�\; �,,� ,A� ,� �� I��. ,,\� ,i` � . �\ � IV?, ,i�' J"'J' �r J "'+`•�\\'� � \ vercut channel2'(SOmm) � � , r,,. ,�� to allow bulking dunng -�� `;�j�\�'' � �; '�V�`: seedbed preparation 1�-/�� and growth of vegetaGon. Fifter W►th Rock Center For Base Fbw Fabric Figure 4.8-Typical Grass-Lined Channels — -------_---- _ ------ -- -- _ _ Fet��:ary 20C�5 Volume tl ��r�s?ructior7 Stonnwater Pc�llutio � Preverali�n -� ;� ^Overlap 6"(150mm)minimum v ;,. .�,4.�, �'— ' � ' `� Excavate Channel to Design . � /" ^ ` ,; �� '�� Grade ar�Cross Section ti,i`�' /�l,-�� ;�� 'i �� ,,,� � .�-%� �� .�� ,f Design Depth ��\� ��, OI�ERCUTCH,4NNEL �',� `!y I � � Longitudinal � 2"(50mm) TOALLOW � '-� i ,�"' �� anchor trench BUL KtNG DUR/N6 SEfDBFO �`, '`'` `""' ''"` ;��` '' PHEPAfIAT/ON � ,-,�.: ;;: ;.� _ • - f � -- - �, �%' ,: � �; ' �„' ��,�„„,� TYP/CAL lNSTALLAT/ON ? ' � W/TN EROS/ON CONTHOL �' � �\�/\ J ��' F � �� // %� BLANKETS OR TUAf � �� /�/� ;�\� �� ' ' � �\��\�� RE/NFORCEMENT MATS ��/�;j�/ �, �j/�//•r , �� .� /i /j�/j\;^ ��/� ��; ��'` ;' �'�� " '' , �`'-\_\;�`'��j\\�;�\��\ �� r �� ;, E �, ,�/� ��, \-:`\`�rsAaml .�;•,�,` Intermittent Check Slot Longitudinal Anchor Trench Shingle-lap spliced ends or begin new roil in an intermittent check slot � --V�r J � -��- Prepare soil and appiy seed before � ,�� ',''t O ,�-y�� installing blankets, mats or other temporary channel Gner system ,' (7 � V � f 4�s ��;' �`� � �v �r / f �r � i 'S � j / '- - - - - - - X � W t � _' -_ � � `�✓ '_ ? ,/K:. �--�'- - iy �':�. �` � �� _ U a i� ! -� /�. ;`:.. / � ��-` . .� / .�" � � .�' ��:�! .� �. ;%/�r/;.j/�,y'"r,/,�/ , ��, NOTES: � 1. Design vclocitics exceeding 2 ft/sec(O.SmJscc)require temporary blankets,mats or similar liners to protcct sccd and soil until vcgctation becomes established. 2.Grass-lined channeis with design velocities excecding 6 ft/scc(2m/sec)should include turf rcinforcement mats. Figu�e 4.9-Temporary Channel Liners 4-62 Volume 1!- Constructron Stormwater Pollution Prevention February 2005 ,� _=,; BMP C220: Storm Drain Inlet Protection Purpose To pre��ent coarse sediment from entering drainage systems prior to permanent stabilization of the disturbed area. Conditions of Use Where storm drain inlets are to be made operational before permanent stabilization of the disturbed drainage area. Protection should be provided for all storm drain inlets do��nslope and within 500 feet of a disturbed or construction area, unless the runoff that enters the catch basin �vill be con��eyed to a sediment pond or trap. Inlet protection may be used anyv►•here to protect the drainage system. It is likely that the drainage system w�ill sti11 require cleaning. Table 4.9 lists several options for inlet protection. .4ll of the methods for storm drain inlet protection are prone to plugging and require a high frequency of maintenance. Drainage areas should be limited to 1 acre or less. Emergency o��erflows may be required where storm��ater pondin<� would cause a hazard. If an emergenc� ��rtic»� � E�n��id«i. ad�iti��nal end-of-pipe treatment may be required. Table 4.9 Storm Drain Iniet Protetion Applicable for Type of Inlet Emergency Pavedt Earthen Protection Overflow Surfaces Conditions of Use � Dro Inlet Protection Exca��ated drop inlet Yes. Earthen Applicable for hea�•}•flows. Eas�- protection temporar�• to mainta�n. Large area flooding will Requirement: 30'X 30'/acre occur Block and gravel drop Yes Paved or Earthen applicable for hea��•concentrated inlet protection floas. Wiil not pond. i Gravel and wire drop No Applicablc for heav}•concentrated � inlet protection flows. Wiil pond. Can withstand � traffic. Catch basin filter. Yes Pa�•ed or Earthen Fre uent maintenance r uired. Curb Inlet Protection Curb inlet protection Small capacity Paved L?sed for=,urd�•, more compact with a wooden weir overflow installation. Block and gra�•el curb 1 es Pa�•ed Sturd�-,bwt limited filtration. inlet pmtection Cul�ert Inlet Protection Cul�•ert inlet sediment 18 month expected life. -�� tra - - —- _- _ _-- --- -- _-- -- - _ _ Y-82 Volume !1- Construction Stormv,ater Pol/ution Preven:�.;n February 2005 �('Cl�/J [J/1(� �1"�,71'tll�.i 1�l'r,�? �17f�1 �'I'C�la'C lit�R — .-�11 tS�:lV��il�t� 1!]l�?l�t]11Lj11:CI11 :1Cl�liil�j i�lt I,�stallation storm drain. Sediment settles out of the storn�water prior to entering the Spc ci frcatinns �tcirm drain. • Depth 1-2 fl as measured from the crest of the inlet structure. • Side Slopes of exca��ation no steeper than 2:1. • '�iinimum��olume of excavation 35 cubic yards. • Shape basin to fit site ��ith longest dimension oriented toward the ;c�n�est inflow area. • lnstall pro��isions for draining to pre��ent standing water problems. • Clear the area of all debris. • Grade the approach to the inlet uniformly. • Drill ��eep holes into the side of the inlet. • Protect v�•eep holes�}�ith screen wire and washed aggregate. • Seal��eep holes when removin� structure and stabilizing area. • It may be necessary to build a tempc�rary dike to the dowm slope side �,t the structure to prevent bypass flow. I3r'�,�k Und Gravel Filter-A barrier formed around the storm drain inlet ��ith standard concrete blocks and gravel. See Figure 4.14. • Height 1 to 2 feet above inlet. • Recess the first row°2 inches into the ground for stability. • �upport subsequent cowses by placing a 2x4 through the block ��pening. • I)o not use mortar. • [_ay sc�me blocks in the bottom rov�� on their side for de��atering the �,�,ol. • Place hard��are cloth or comparable wire mesh with Yz-inch openings ��er all block openings. • Piace gra�el just below the top of blocks on slopes of 2:1 or flatter. • An alternati��e design is a gravel donut. • Inlet slope of 3:1. • Outlet slope of 2:1. • 1-foot u�ide level stone area bet��een the structure and the inlet. • Inlet slope stones 3 inches in diameter or larger. • Outlet slope use gravel ',!-to 3/�-inch at a minimum thickness of 1-foot. - --- — __ ------ — --- _ _ _— _--- _ _ _ . Februa,ry 2005 Volume (!- Consfruc!ion Stormwa!er Poliut��n Preve!�tion 4-�?3 -, Z� Plan View A Orain Grats .\,�-� `�� V:, •�, Lt;-`�, � ��tx c� o � - �-��r.� ��a z� :3;._.� �°�.,-�, ��,�,� ,�� 4,,�� •`.� ,. ^� _i :��C?r� 1p,.,-^�� o R � _ ',�Yp`_ .� .\ � .':�c.�_ - y� � � �•o c�; _.__�COf1CfEtB ��C� �� (��` B�OC�C li � p `�c , :� . �-t4� v I i i ;�a✓/�a.-_ -- .__/�'- � �': ��1L�� ' �,� ;=_ < � � �.� ,� , ,..�L -�] � ��.�'�_ _ ,_,�i,-�x��,? .s.__ � Gravel .��r�<,�,�, C�--" - - -. BackfiM �„�- � �'=` �� o� ?�} o':'r � .° o- - - \G��yJ �C 4c y. (�'� �} �. i+. V:1 e<;. �'��s"c6�� - _. _ ^�C.i _��' -_O,i,-r.. _ �� A h Section A - A c��«e�B� w��m s«�o� Fi�er Fabric Gravei Bacictitl- �,e� � Water 'i �� Ponding Height e�- ,r- -�, -.�u��:,- _ i Water --,--, — �f_. ` _ - - - - �-rll' - - �-� �fOp�f1� . .. Notes: 1 Drop infet sediment barriers are to be used tor small,nearty level drainage areas.(less than 5°�) 2. Excavate a besin of sufficieM size adjacent to the drop inlet � The top o([he suvcture(ponding hei4:ht)must t+e weil heloH the ground de�•aaon downslope to pre�em runotT from h��ccing the inlrt. A tem'v�rar�dike ma� br necessan on the doH slo;+e side of the sWcture Figure 4.14-Block and Gravel Filter Gruve!and Ti'rre .�lesh Filter- A gravel barrier placed over the top of the inlet. This structure does not pro��ide an o��erflow. ' • Hardware cloth or comparable «�ire mesh with %-inch openings. • Coarse aggregate. • Height 1-foot or more, 18 inches wider than inlet on all sides. • Place wire mesh over the drop inlet so that the w7re extends a I minimum of 1-foot beyond each side of the inlet structure. • If more than one strip of inesh is necessary, overlap the strips. • Place coarse aggregate over the wire mesh. • The depth of the gravel should be at least 12 inches over the entire inlet o}�ening and extend at least 18 inches on all sides 4-84 Volume 11- Construction Stormwater Polfution Prevention February 2005 'I �-� ! � �:Uc�it��,L��U7 1'll(c'l:+ - �Ilti�t"i� ��l��ll;� ��C �c:�l�'tlei� t)�� l�lc: IIla11U1�]�ilU�'I' i��C use at construction sites. The limited sediment storage capacit}� increa�� the amount of inspection and maintenanee required, which may be dail� for heavy sediment loads. The maintenance requirements can be reduc«1 by cambining a catchbasin filter��ith another type of inlet protection. li This type of inlet protection provi�es flow bypass ��ithout o�•erflow and ' therefore may be a better method 'or inlets located along acti��e rights-c�t�- «�av. • 5 cubic feet of stora�c. • Dewatering pro�Tisions • 11igh-flo«�bypass that will no: clog under normal use at a co��struction ' �itz. • l he catchbasin filter is inserted in the catchbasin just below the �,rating. C ��i� Inlet Protection with Wooden [�'eir— Barrier formed around a curb inlet with a wooden frame and gra�el. • Wire mesh with :-inch openinas. • Extra strength filter cloth. • Construct a frame. • Attach the�r�ire and filter fabric to the frame. • Pile coarse w�ashed aggregate a�ainst wire/fabric. • Place weight on frame anchors. Block and Grm�e!Curb Inlet Prorecrion—Barrier formed around an inlet »ith concrete blocks and gravel. See Figure 4.14. • Vl%ire mesh with '/-inch openings. • Place two concrete blocks on their sides abutting the curb at either side ��f the inlet opening. These arz spacer blocks. • Place a 2x4 stud through the outer holes of each spacer block to align t I�e front blocks. • Place blocks on their sides acrass the front of the inlet and abutting the ��acer blocks. • Piace v��ire mesh over the outside vertical face. • Pile coarse aggregate against the wire to the top of the barrier. Gn•b and Gutter Sediment Barrier— Sandbag or rock berm (riprap and a�gregate}3 feet high and 3 feet„�ide in a horseshoe shape. See Figure -1.16. • Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 feet high and 3 feet w�ide, at least 2 feet from the inlet. • Canstruct a horseshoe shaped �edimentation trap on the outside of the berm sized to sediment trap statldards for protecting a cult�ert inlet. -- -- —--- --- _ --- —___ __ __ _ --- February 20d5 Volume 11- Constructron Stormv✓ater �alluflon Preve+�fion 4-85 l '`��' ►lainte�rance • Catch basin filters should be inspe�ted trequently, especially after Srandards storm events. If the insert becomes clogged, it should be cleaned or replaced. • For systems using stone filters: If the stone filter becomes clogged w-ith sediment, the stones must be pulled away from the inlet and cleaned or replaced. Since cleaning of gravel at a construction site may be difficult, an alternative approach v�•ould be to use the clogged stone as fill and put fresh stone around the inlet. • Do not wash sediment into storm drains w�hile cleaning. Spread all eaca�-ated material e��enly o��er the �urrounding land area or stockpile and �tabilize as appropriate. _— —— ---___ _ _--- — _ _ --- ---- =-86 Volume J!- Construction Stormwater Pollutron Prevention February 2005 �J� _ � Plan View � Back of Sidewalk A Catch Basin .i' i 2x4 Wood Stud Back of Curb Concrete Block ._— . Curb inlet _ __. y --- S � v�+ ' -V+.� ;. .. . -.`� C �}�Vp_ r�.. �;�� ' �j'3"� �� ---- `�.�� "- ' ` � .�c � �� - '�--� - .-�. - � � _—�__ d:� � �' " '� . T-,� . ��`, . Y"{�, ?�'Y€��`�-�� _ 3'�:4 k.'� �_ o- � �- �. _ - ,`. _ �.��`._- _.�yq�y � .s��. . . - - . YYs _. Wire Screen � Fitter Fabric A Concrete Bbck Section A � A '�'�Drain Gravel (20mm) 'h"Drain Gravel (20mm) Ponding Height -- �Concrete Block Overfl�et_ _ - . _-_ -_ 4�r_ _ . _ -- Curb Inlet --—�= LNire Screen or Filter Fabnc 4 Wood Stud Catch Bas�n (100x50 Timber Stud) NOTES: 1. Use block and gravel type sediment bamer when wrb mlet is Iocated in gently sloping street segment. where water can pond and allow sediment to separate from runofl. 2. Barrier shall allow for overflow frwn severe storm event. 3. Inspect barriers and remove sediment after each storm event. Sediment and gravel must be removed from the traveled way immediately. Figure 4.15-Block and Gravel Curb Inlet Protec�on - --_ _ -- - -- February 2005 '✓clume ll- Construcfron Stom�rrater Pollution Preven�io�; 4-8� ?,� �. Plan View �88ck of Sidewalk -- -v — Buriap Sacks to Catch Basin Ovartap onto Curb ' Curb In�t , -- —_-- ^— Back ot Curb� _—L RUNOFF 7 } RUNOFF SPILLWAY \ �'�/ , , , _- \ � , i � � t " • �`—� Gravel Filled Sandbags ;��.�j. ��.� Stacked Tightly NOTES: 1.Place curb type scd�ent barriers on gently sloping strcet segmenu,where waur can pond and aUow sediment to sepan►te from runoff. 2.Sandbags of eitber burlap or woven'geotexdid fabric,art fiUed with gravel,layered and packcd tightly. 3.Leave a one sandbag gap in t�top row to pro�lde a spillway for ocerflow. 4.inspect bamers and remo��e stdiment after each storm e�•ent.Sediment and gravel must be rcmo��ed from the travded u�ay immedistely. Fi ure 4.16 - Curb and Gutter Barrier 4-88 Voi�:n?e ll- Construction Stormwater Pollution Prevention February 2005 1 % 'L tit.`.i.i�,i�.�c7�t'! ri.71�LiIiCJi', ��-C'o-�c/7(�i.:n `�1��-. Appendix D — General Permit WAR #3Q3557 32 'S�6a ;iu�_�, Storm,water Pcllution Preven,iron Ptan Appendix E - Site Inspection Forms (and Site Log) The results of each inspection shall be summarized in an inspection report or checklist that is entered into or attached to the site log book. It is suggested that the inspection report or checklist be included in this appendix to keep monitoring and inspection information in one document, but this is optional; however, it is mandatory that this SWPPP and the site inspection forms be kept ansite at all times during construction, and that inspections be performed and documented as outlined below. , At a min�mum, each inspection report or checklist shall include. a. Inspection dateitimes b. Weather information: generat conditions during inspection. approximate amount of precipitation since the last fnspection, and approximate amount of precipitation within the last 24 hours. c. A summary or list of all BMPs that have been implemented, including observations of all erosion/sediment control structures or practices. d. The following shall be noted: i. locations of BMPs inspected, ii. locations of BMPs that need maintenance. iii. the reason maintenance is needed. iv. locations of BMPs that failed to operate as designed or intended, and v. locations where additional or different BMPs are needed, and the reason(s) �Y e. A description of stormwater discharged from the site. The presence of suspended sediment, turbid water. discoloration, and/or oil sheen shall be noted, as applicable. f. A description of any water quality monitoring performed during inspection. and the results of that monitoring. g. General comments and notes, including a brief description of any BMP repairs. maintenance or installations made as a result of the inspection. h. A statement that, in the judgment of the person conducting the site inspection. the site is either in compliance or out of compliance with the terms and conditions of the SWPPP and the NPDES permit. If the site inspection indicates that the site is out of compliance, the inspection report shall include a summary of the remedial actions required to bring the site back into compliance, as well as a schedule of implementation. i. Name, title, and signature of person conducting the site inspection; and the following statement: "I certify under penalty of law that this report is true. accurate, and complete, to the best of my knowledge and belief. When the site inspection indicates that the site is not in compliance with any terms and conditions of the NPDES permit, the Permittee shall take immediate action(s)to: stop, contain. and clean up the unauthorized discharges, or otherwise stop the noncompliance; correct the 33 15564.005 doc Stormwater PoHution Prevention Plan problem(s); implement appropriate Best Management Practices (BMPs), and/or conduct maintenance of existing BMPs; and achieve compliance with all applicable standards and permit conditions. In addition, if the noncompliance causes a threat to human health or the environment, the Permittee shall comply with the Noncompliance Not�cation requirements in Special Condition SS.F of the permit. 34 15564.00S doc , _ '��t, Stormwater PoUution Prevention Plan Site Inspection Form General Info�rnation Project Name: Marriott Residence Inn Inspector Name: Lewis Conklin Title: CESCL# : Date: Time: Inspection Type: - After a rain event � Weekly � Turbidity/transparency benchmark exceedance - Other Weather Precipitation Since last inspectian In last 24 hours Description of General Site Conditions: Inspection of BMPs Element 1: Mark Clearing Limits BMP: Location �nspected Functioning problem/Corrective Action Y N Y N NIP i BMP: Location Inspected Functioning problem/Conective Action Y N Y N NIP Element 2: Establish Consbuction Access BMP: Location Inspected Functioning Problem/Corrective Actian Y N Y N NIP BMP: Location �nspected Functioning Problem/Corrective Action ' Y N Y N NIP 35 15564 005.doc � � � ; Stormwater Potiulion Preven,tion Plan EJement 3: Control Flow Rates BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: L�ation �ns�cted Functioning Probiem;Corrective Act�on Y N Y N NIP � E/ement 4: /nsial/Sediment ConVols BMP: Location �nspected Functioning Problem�Corrective Actian Y N Y N NIP BMP: Location �nspected Functioning problem�Corrective Action Y N Y N NIP BMP: Location ��spected Functioning ProblemlCorrective Action Y N Y N NIP � � BMP: Location �nspected Functioning Problem�Corrective Action Y N Y N NIP BMP: Location ��spected Functioning problemlCorrective Action Y N Y N NIP 36 �sssa.005 d�� :� Stormwater Pollution Prevention Plan ' Element 5: Stabi/ize Soi/s BMP: Location Inspected Functioning problem/Co►rective Action Y N Y N NIP BMP: Location Inspected Functioning probiem/Carrective Action Y N Y N NIP BMP: Location �nspected Functioning problem/CoRective Action Y N Y N NIP BMP: Location Inspected Functioning problem/CoRective Action Y N Y N NIP E/ement 6; Protect Slopes ' BMP: Location ��spected Functioning problem/Corrective Action Y N Y N NIP BMP: Location �nspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action ; 37 15564.00S.doc . � Siormwater Poliutron Prevention Plan Element 7: Protect Drain Inlets BMP: Location ��spected Functioning problem/Corrective Action ' Y N I��i Y N N I P BMP: Location Ins�cted Functioning Problem/Corrective Action Y N Y N NIP BMP: �ocation �nspected Functioning problem/Corrective Action Y N � Y N NIP Element 8: Stabilize Channeis and Out/ets BMP: Location Inspected Functioning Problem/Corrective Action Y N 'Y N NIP Bti�1P: Location �nspected Functioning problem/CoRective Action Y N �� N NIP BMP Location �nspected Functioning Problem/Corrective Action Y N Y ; N NIP BMP: L�cation �nspected Functioning Problem/Corrective Action Y N Y N NIP 38 �55oa oc�do� ' �� Stormwater Potlution Prevention P/an E/ement 9: Contro/Poitutants BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP Element 10: Control Dewatering BMP: Location ��spected Functioning problem/Co�rective Action Y N Y N NIP BMP Location Inspect� Functioning problem/Corrective Action Y N Y N NIP BMP: Location �nspected Functioning problem/Co�rective Action Y N Y . N NIP � Stormwater Discharges From the Site Observed? Problem/CoReciive Action Y N Lacation I Turbidity Discoloration Sheen Location ' Turbidiry Discolo�ation Sheen , 39 'S564 �05 dx Stormwater Pollution Prevention Plan Water Qualit Monitorin Was any water quality monitoring conducted? _= Yes � No If water quality monitoring was conducted, �ecord resufts here: �� i � If water quality monitoring indicated turbidity 250 NTU or greater; or transparency 6 cm ! or less, was Ecology notified by phone within 24 hrs? J Yes - No If Ecology was not�ed, indicate the date, time, contact name and phone number below: � Date: I Time: I Contact Name: ' Phone #: j General Comments and Notes � Include BMP re airs, maintenance, or installations made as a result of the ins ection. � Were Photos Taken? - Yes ❑ No ' If hotos taken describe hotos below: 40 �55fi4 005 doc �•1G'�G' Stormwater Po!lution Prevention Plan Appendix F — Engineering Calculations 41 �sssa oo5.do-� ,� - KCRTS Command CREATE a new Time Series - ----------------------- rr��ction of Runoff Time Series _ �— �� _,.-..__._.-. . �ea-Tac �cmput�ng Ser�es : 15564ESC.tsf _ _�i�nal Scale Factor : 1. 00 Data Type : Reduced _ �ating 15-minute Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\5TTG15R.rnf . �=11 Grass 0.06 acres Loading Time Series File:C:\KC_SWDM\KC_DATA�STEI15R.rnf . �. -�- =_�-�s 1.11 acres -------------- �'otal Area : 1. 17 acres --� . : _ . �.arqe: 1 . ?4 CF: at 6:30 on Jan 9 in Year 8 Storing Time Series File: 15564ESC.tsf . . _ �= Series Computed ::CRTS Command �--.te_- tre Analysis TOOLS Module - - - - ---—---------------------- -.nalysis Tools Command - ----------- ---------- _..:�<<.:�e PEAKS and Flow Frequencies - --------------------------------- Loading StagejDischarge curve:15564esc.tsf . __��.- :ze,uc.��y Analysis - ------------------------------------------------------- -_..:- ._�� :Gs File:15564esc.tsf -� ��_-' i_.��ation:SPa-'?'ac . ��;.:encies & Peaks saved to File: 15564ESC.pks . .=i:-zl-.-sis Tools Command - --------------------- ..�T�TRN t� Pre�.��cu� Mer.0 - - - - - - - - - -- - -- - - - - - - - - - _ _ _ � _��[''.�T.3_:�� _.._� KCRTS Program - - - - - - - — - - - - - - - - - Ficw Frequer�cy Pr.alys��s i�me �eries File:15564esc.tsf Froject Location:Sea-Tac - -Annual Peak Flow Rates--- -----Flow Frequency Analysis------- -=�w Rate Rank Time of Peak - - Peaks - - Rank Return Prob CFSi (CFS) Period = .529 6 8/27/O1 18:00 1.34 I 100.00 0 .990 � .369 8 9/17J02 17:45 1. 01 _ 2 25. 00 0 . 960 i.01 2 12/0$J02 17:15 0.72� 3 10. 00 0.904 � .426 7 8/23j04 14:30 0.595 4 5.00 0.800 � .564 5 10/28/04 16:00 0.564 5 3_40 0 .66? � .595 4 10/27J05 10:45 0.529 6 2_00 0 .500 : .720 3 10/25/06 22:45 0.426 7 1_30 0 .231 1. 34 1 1/09108 6:30 0.369 8 1 . 10 0 .091 __ ��-�-d =eaks � . �= 5: . _., . . �_n� _=�i-�,��:t -=�F "��.__� �r_= -- . __�� = 2, 080t2 year peakj _ (2, 080) t0. 529 cfs} = 1, 100 SF _�diment Trap surface area provided = 760 SF plus two Baker Tanks ; _ _�.�-, . t' � 9.Q BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT � i ' � Site Improvement Bo. ,u Quantity Worksheet Webdata �oa8 � King County Department of Development & Environmental Services 900 O�kesdale Avenue Southwest Renton, Washington 98057-5212 For alternate formats, call 206-296-6600. 206-296-6600 TTY 206-296-7217 Projecc Name: Marriott Residence Inn �ate: 2/23/2016 / Revised 4/8/2016 �ocation: 1100 Lake Washington Blvd., N.E., Renton, WA Project No.: 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 Bond C�uantity Worksheet.xls Report Date 4/7/2016 Web date ?/2008 Site Improvement Bo„u Quantity Worksheet Unit #of Referenco# Price Unit Gluanti A lications Cost EROSION/SEDIMENT CONTROL Number Backfill & com action-embankment ESC-1 $ 5.62 CY Check dams, 4"minus rock ESC-2 SWDM 5 4.6.3 $ 67.51 Each 26 1 1755 Crushed surfacin 1 1!4" minus ESC-3 WSDOT 9-03.9 3 $ 85.45 CY Oitchin ESC-4 $ 8.08 CY 83 1 671 Excavation-bulk ESC-5 $ 1.50 CY Fence, silt ESC-6 SWDM 5.4.3.1 $ 1.38 LF 674 1 930 Fence, Tem ora NGPE) ESC-7 $ 1.38 LF ' H droseedin ESC-8 SWDM 5 4.2.4 $ 0.59 SY 'i Jute Mesh ESC-9 SWDM 5 4.2.2 $ 1.45 SY '� Mulch, b hand, straw, 3"dee ESC-10 SWDM 5.4.2.1 $ 2.0� SY I Mulch, b machine, straw, 2"dee ESC-11 SWDM 5.42.1 $ 0.53 SY '� Pi in , tem ora , CPP,6" ESC-12 $ 10.70 LF 65 1 696 Pi in , tem ora , CPP, 8" ESC-13 $ 16.10 �F Pi in , tem ora , CPP, 12" ESC-14 $ 20.70 LF Plastic coverin ,6mm thick, sandba ed ESC-15 SWDM 5.4.2.3 $ 2.30 SY Ri Ra , machine placed; slo es ESC-16 WSDOT 9-13.1(2) $ 39.08 CY Rock Construction Entrance, 50'x15'x1' ESC-17 SWDM 5.4.4.1 $ 1,464.34 Each Rock Construction Entrance, 100'x15'x1' ESC-18 SWDM 5.4.4.1 $ 2,928.68 Each 1 1 2929 Sediment pond riser assembl ESC-19 SWDM 5.4.5.2 $ 1,949.38 Each Sediment tra , 5' hi h berm ESC-20 SWQM 5.4.5.1 $ 17,91 LF Sed. trap, 5'hi h, nprapped s iUwa berm section ESG21 SWDM 5.4.5.1 $ 68.54 LF Seedin , b hand ESC-22 SWDM 5.4.2.4 $ 0.51 SY Soddin , 1"dee , level round ESC-23 SWDM 5.4.2.5 $ 6.03 SY Soddin , 1"dee , sloped round ESC-24 SWDM 5.4.2.5 $ 7.45 SY TFSC Su ervisor ESC-25 $ 74.75 HR Water truck, dust control ESG26 SWDM 5 4.7 $ 97.75 HR WRITE-IN-ITEMS **"'" see a e 9 Baker Tanks $ 1,500.00 Each 2 1 3000 ESC SUBTOTAL: $ 9,980.20 30%CONTINGENCY 8 MOBILIZATION: $ 2,994.06 ESC TOTAL: $ 12,974 26 COLUMN: A Page 2 of 9 C"• � Urnt prices updated 02/12/02 �,., Version: 11/26/200A E3ond �uantity Worksheet.xls Repart Date 4l7/2016 Site Improvement Bc��' Quantity Worksheet Webdate �Z�oz,zooa I Exiating Future Public Private Quantity Comploted � Right-of-Way Road Improvements improvements (Bond Reducdon)' , 8 Oraina e Facilities Quant. Unit Pnce Unit Ouant. Cost Quant Cost �uant. Cost Com lete Cost N I Backfili 8 Com action-embankment GI- 1 $ 5.62 CY 930 5,226 60 Backfill&Com action-trench GI-2 $ H 53 CY Clear/Remove Brush,b hand GI-3 $ 0.36 SY Clearin /Grubbin /Tree Removal GI-4 $ 8,876.16 Acre 1.45 12,870.43 Excavalion-bulk GI-5 $ 1.50 CY 28 42.00 19022 28,533.00 Excavation-Trench GI-6 $ 4.06 CY Fencin ,cedar,6'hi h GI-7 $ 18 55 l_F Fencin ,chain link,vin coated, 6'hi h GI-8 $ 13 44 LF Fencin ,chain link, ate,vin I coated, 2 GI-9 $ 1,271.81 Each Fencin ,s lit rail,3'hi h GI- 10 $ 12 12 LF Fill&com act-common barrow GI- 11 $ 22.57 CY FiII R com act- ra�el base GI-12 $ 25.48 CY Fill 8 com act-screened to soil GI- 13 $ 37.85 CY Gabion, 12"dee ,stone filled mesh Cil- 14 $ 54.31 SY Gabion, 18"dee ,stone filled mesh GI-15 $ 74.85 SY Gabion,36"dee ,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 1230 1,168.50 Monuments,3'Ion GI- 19 $ 135 13 Each Sensitive Areas Si n GI-20 $ 2.88 Each Soddin , 1"dee ,slo d round G�-21 $ 7 46 SY Surve in ,line 8 rade GI-22 $ 788.26 Da 3 2,364.78 14 11,035.64 Surve in ,lot locaiion/lines GI-23 $ 1,556.64 Acre Traffic control crew 2 Fla ers GI-24 $ 85.18 HR Trail,4"chi ed wbod GI-25 $ 7 59 SY Trail,4"crushed r.inder GI-26 $ 8 33 SY Trail,4"to course GI-27 $ 8.19 SY Wall,retainin ,concrete GI-28 $ 44 16 SF Wall,rocke GI-29 $ 9 49 SF Paqe 3 of 9 SUBTdTAL 3.575.28 57,665 67 v \�� Urnt prices updated: 02l12102 'KCC 27A authorizes only one bond reduction. VefslOn: 11/26/08 Rond(�iianUty Worksheet xls RepoR Date 4/7/2016 Site improvement Bc ' Quantity Worksheet webdate 12/02l2008 Existing Futuro Public Private Bond Roduction' Riflht-of-way Road Improvements Improvements 8 Draina o FaciGties (�uani Unit Price Urtit C]i.i2n1 Cost ��a�rnl Cost (7uant. Cost Com lete Cost ROADIMPROVEMENT No. AC(>nndin ,4'widc maChine-= t000s RI- 1 $ 2t3 00 SY AC Grindm ,4'wide machine 1000 200 F21-2 $ 15 00 SY AC Grindin ,4'wide machlne>2000s RI-3 $ Z60 SY AC Removal/Ois osallRe air RI-4 $ 67 50 SY Barricade,t e I RI-5 $ 30 03 LF Barricade,t e I11 Permanent RI-B $ 45.05 LF Curb 8 Gutter,rolled RI-7 $ 17 00 LF Curb 8 Gutter,vertical RI-8 $ 1Z 50 I..F 300 3,750.�0 Curb and Gutter,demolition and dfs osa RI-9 $ 18.00 LF Curb,extruded as halt RI- 10 $ 5 50 l,F Curb,extruded concrete RI- 11 $ 7 00 LF Sawcuf,as halt.3"de th RI- 12 $ 1.85 L� 300 555.0� Sawcut.concrete, er 1"de th RI- 13 $ 1.69 LF Sealant,as halt RI- 14 $ 125 LF 300 375.00 Shoulder,AC, see AC road unit rice RI- 15 $ SY Shoulder, ravel,4"thick RI- 16 $ 15.00 SY Sidewalk,4"thick RI- 17 $ 35.00 SY 106 3,710.00 50 1,750.00 Sidewalk,4"thick,demolition and dis os RI- 18 $ 29 50 SY Sidewalk,5"thick RI-19 $ 38.50 SY Sidewalk,,5"thick,demaGtion and dis os RI-20 $ 37.56 SY Si n,handic,a RI-21 $ 85.28 Each Stri in , er stall RI-22 $ 5.82 Each 92 535.44 Stn in ,therma�las6c,((or r.�osswalk RI -23 $ 2 38 SF Stripin .A"reflectorized line RI-24 $ 025 lF Page 4 of 9 SUBTOTAL �8;399�96"` 2,285.44 2�7, dL�5 �J � _.� Unit prices updated: 02J12l02 'KCC 27A authonzes onty pne bonci reduction. VGfSi011: 11/26/0$ B�nd��u��n1�1y W�rksht�r�txls Report DatP. ��7J2016 L— Site Improvement Bc -- -' Quantity Worksheet Webdate 12/02/2008 Existing Futuro Public Private Bond Roduction' Right-of-way Road Improvements Improvaments 8 Draina e Facilities �uant. Unit Pnce Unit Quanl. Cost Quant Cost Quant Cost Com lete Cost ROAD SURFACING (4"Rock=2.5 base& 1.5"top course) For'93 KCRS(6.5"Rock=5"base 8�1.5"top course) f"or KCRS'93 (addition�l 2 5"base add RS- 1 $ 3.60 SY AC Overla , 1.5"AC RS-2 $ 11.25 SY AC Overla .2"AC RS-3 $ 15.00 SY 404 6,060.00 AC Road,2",4"rock,First 2500 SY RS-4 $ 21.00 SY AC Road.2",4"rock,Qt .over 2500SY RS-5 $ 19.00 SY 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".C�t .Over 2500 SY RS-9 $ 25,00 SY AC Road,6",First 2500 SY S- 1 $ 33 10 SY 150 4,965.00 AC Road,6",ot .Over 2500 SY S- 1 $ 30.00 SY As halt Treated Base,4"thlck S- 1 $ 20.00 SY Gravel Road.4"rock,First 2500 SY S- 1 $ 15.00 SY Gravel Road,4"rock,Qt .over 2500 SY S- 1 $ 8.50 SY PCC Road,S".no base,over 2500 SY S- 1 $ 27.00 SY PCC Road, 6",no base,over 2500 SY S- 1 $ 25.50 SY Thickened Ed e S- 1 S 8 60 LF Page 5 of 9 SUBTOTAL 11,025.00 ' � � \ Unit prices updated: 02/12/02 'KCC 27A authonzes oniy one bond reducUon. VefSion: 11/26/08 Bond Quantity Worksheet.xls Report Date: 4/7/2016 Site Improvement Bc ' Quantity Worksheet Webdate 1 210 2/2 00 8 Existing Futurp Public Private Bond Roduction• Right-of-way Road Improvemonts Improvements 8 Draina e Facilities Quant Unit Price Unit Quant Cost Quant Cost Quenl. Cost Com lele Cost DRAINAGE (CPP=Corrugated Plastic Pipe,N 12 or Equivalent) For Culvert nces, Avera e ot 4�cover was assumed Assume rtorated PVC is same nce as soi�d i Access Road. R/D D - 1 $ 21 00 SY Bollards-fixed D-2 $ 240 74 Each Bollards-removable D-3 $ 452.34 Each ' CBs include hame and lid CB T e I D-4 $ 1,257.64 Each /,iZ`� 7 3 3,772.92 CB T e IL D-5 $ 1,433.59 Each CB T e II,48"diameter D-6 $ 2,033 57 Each 4 8,134.28 1 2,033.57 for additional de th over 4' D-7 $ 436.52 FT 5 2.182 60 2 873.04 CB T 11.54"diameter D-8 $ 2,192.54 Each for additional de th over 4' D-9 $ 486.53 FT CB T e II,60"diameter D- 10 S 2,351.52 Each for additionai de th over 4' D-11 $ 536.54 FT CB T II,72"diameter D- 12 $ 3,212 64 Each for addilional de th over 4' D-13 $ 69221 FT Throu h-curb Inlet Framework Add D-14 $ 366.09 Each Cleanout,PVC,4" D- 15 $ 130.55 Each Cleanout,PVC,6" D- 16 $ 174.90 Each Cleanoul,PVC,8" D- 17 $ 224 19 Each 14 3,138.66 Culvert,PVC,4" D-18 $ 8.64 LF Culvert,PVC,6" D- 19 E 12 60 LF Culvert,PVC, 8" O-20 $ 13 33 LF 565 7,531 45 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" 0-25 $ 37.74 LF Culvert,CMP,24" D-26 $ 53 33 LF Culveri.CMP,30" D-27 $ 71.45 LF Culvert,CMP,36" D-28 $ 112.11 LF Culvert,CMP,48" D-29 $ 140.83 LF CulveA,CMP,60" D-30 S 235.45 LF Culvert,CMP,72" D-31 $ 302.58 LF Page 6 oi 9 SUBTOTAL 10,316.88✓ 17,349.64 C`' � � Unit prices updated 02/12�0�' 'KCC 27A authorizes only one bond reduction. VefSiOn' 11/26�OH F3ond Quanlity Worksheet xls Report Date 4/'l2016 Site Improvement Bc -' Quantity Worksheet W�date 12/02/2008 Existing Future Public Privata Bond Reduction` Right-oi-way Road Improvements Improvements DRAINAGE CONTINUED 8 Drainage Facilities Quant. No Unit Pnce Unit �uant. Cost Qu�nt Cost �uant. Cost Com lete Cost Culvert,Concrete,8" D-32 $ 21 02 LF Culvert,Concrete, 12" D-33 $ 30 05 LF Culvert,Concrete, 15" D-34 $ 37.34 LF Culveh,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 $ 1070 LF Culvert,CPP,8" D-42 $ 16,10 LF Culvert,CPP, 12" D-43 $ 20 70 LF 273 5651.1 436 9025.2 Culvert,CPP, 15" D-44 $ 23 00 LF Culvert,CPP, 18" D-45 $ 27.60 LF Culvert,CPP,24" D-46 $ 36.90 LF Culvert,CPP,30" D-47 5 48.30 LF Culveri,CPP,36" D-48 $ 55.2� LF Ditchin D-49 $ 8.08 CY Flow Dis rsal Trench 1,436 base+ D-50 $ 25 99 LF French Dram 3'de th D-51 $ 22.60 LF Geotextile,laid in Irench, o ro lene D-52 $ 2.40 SY Infiltration ond testin D-53 $ 74.75 HR Mid-tank Access Riser,48"dia, 6'dee D-54 $ 1,605.40 Each Pond Overflow S illwa D-55 S 14.01 SY Restrictor/Oil Se arator, 12" D-56 $ 1,045.19 Each 1 1045.19 Restrictor/Oil Se arator, 15" D-57 $ 1,095.56 Each Restrictor/Oil Se arator, 18" D-58 $ 1,146.16 Each Ri ra , laced D-59 $ 39.08 CY Tank End Reducer 36"diameter D-60 $ 1,000.50 Each Trash Rack, 12" �-61 $ 211.97 Each Trash Rack, 15" D-62 $ 237.27 Each Trash Rack, 18" D-63 S 268.89 Each Trash Rack,21" D-64 5 306 84 Fach Page 7 of 9 SUE3TOTAL 5651 1 � 10070.39 C`� � .� Unit prices updated: 02l12/02 'KCC 27A authorizes only one bond reduction. VerSlOn: 11/26l08 Bond Quantity Worksheet.xls Report Date:4/7J2016 Site Improvement Bc��' Quantity Worksheet WeGdate 72/02/2008 Existing Futuro Public Private Bond Reduction' Right-of•way Road Improvementa improvements 8 Draina e Facillties Quant Unit Price Unit Quant. Price Quanl Cost Quam. Cost Com lete Cost PARKING L T S No. 2"AC,2"to course rock&4"borrow PL-1 $ 21 00 SY 2"AC, 1.5" to course&2.5"base cou PL-2 $ 28.00 SY 4"select borrow PL-3 $ 4.55 SY 1 5"to course rock&2.5"base course Pl -4 S 11.41 SY , TILITY POLES R T N Utilit ole relocetion casts must be accam anied b FrancMiso UUN 's Cost Statement I Utili Pole s Relocation UP-t Lum 5um Street Li ht Poles w/Luminaires UF-2 F.ach WRITE-IN-ITEMS (Such as detentionlwater ualit vaulis No_ 68'x 20'DETENTION VAULT WI-1 $ 44,200 Each 1 442U0 WATER QUALITY VAU�T #MWS-I-8-8- WI-2 $ 31,000.00 SY 1 31000 WI-3 CY WI-4 LF WI-5 FT WI-6 WI-7 - WI-8 WI-9 , wi-to ql, �4� SUBTOTAI `g5-289-9� I�(5, �5`�` SUBTOTAL(SUM ALL PAGES): ��8.26 87,371 t4 30%CONTINGENCY 8 MOBIUZATION: 34,247.48 26,211 34 GRANDTOTAL: �-#4$;4Ab-�1-- 113,582.48 COLUMN: � B C D E Page 8 of 9 � C�'!O) �65 O � � �� ?�1 ��'� --a - � �------ Urnt pnces updated 02/12i02 'KCC 27A authorizes only one bond reduclion. VEfSiOn 11/26/OS [�ond eauarn�ry worksr,eet xis Report Date 4l7/201f Site Improvement Bc„u Quantity Worksheet Wf�t,clate �;Zoos Original bond computations prepared by: Name: JERRY JACOBS oace: 2/23/2016/ Revised 4/8/2016 PE Registration Number: 27694 Tel.#: (425)251-6222 F�rm Name: BARGHAUSEN CONSULTING ENGINEERS, INC. Address: 18215 72ND AVENUE SOUTH, KENT, WA 98032 Pro)ect No: ROAD IMPROVEMENTS 8 DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND' PUBUC ROAO 8 DRAINAGE AMOUNT BOND'AMOUNT MAINTENANCE/DEFECT BOND' REQUIRED AT RECORDING OR Stabilization/Erosion Sediment Control (ESC) (A) $ 12,974.3 TEMPORARY OCCUPANCY'"' Existing Right-of-Way Improvements (B) $ 148,405.7 Future Public Road Improvements 8 Drainage Facilitie (C) $ - I Private Improvements (D) $ 113,582.5 Calculated (�uantiry (:ornplete:d (E) $ - Total Right-of W�y�nd/or Site Restoratinn f��nrl'/" (A+B) $ 161,380.0 (F irst S1.5U0 of bond' shall be ca:,li � PerfonnanceBond'Amount (A+[3+C+D) - TOiAI (T) $ 274,962.5 Tx0.30 $ 82,488.7 OR irnmum on amount is I�educed Perionnance f3ond' rotal """ (T-E) $ 274,962.5 Use larger o x or - (B+C) x Mainlenance/Defect Bond'Total 0 25 = 5 37,101.4 NAME OF PERSON PREPARING BOND' REDUCTION Date ' NOTE: The word"bond"as used in this document means any financial guarantee acceptable to King County " NOTE: KCC 27A authorizes right of way and site restora6on bonds to be combined when both are required The restoration requirement shall include the total cost for all TESC as a minimum,not a maximurn In add�t�on corred�ve work both or- and oft-s�te needs to be �nciuded Quantities shall reflect worse case scenarios not just minimum requirements. For example, if a salmomd stream may be damaged. some eshmated costs for restorat�on needs to be reflected in this amount. The 30%contingency and mobilization costs are computed in this quantity "'NOTE: Per KCC 27A,total bond amounts remaining after reduction shall not be less than 30%of the original amount(T)or as revised b ma or design changes SURETY BOND RIDER NOTE: If a bond rider is used,minimum additional performance bond shall be �- 1 13,582.5 (C+D)-E REQUIRED BOND'AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DDES ��' Nage 9 of 9 Unit pnces updated 02/12/02 Check out the DDES Web site at www.kinqcountv.qov/permits Vers�on 11/26I08 Ran�1 C�iiantity Worksheet xls Report D�te 417I�016 10.0 OPERATIONS AND MAINTENANCE MANUAL , , r; ,J� �, APPEIr'DIX A MAINTENATCE REQUIREMENTS FOR FLOW CONTROL,CONVEYANCE,AND VVQ FACILITIES NO. 3-DETENTION TANKS AND VAULTS � Maintenance Defect a Problem Condidons When Maintenance is Needed Results Expected When � ComponeM Maintenance is Performed Site Trash and debns My trash and debris which exceed 1 cubic toot Trash and debns deared from site. per 1,000 square feet(this is about equal to the amount of trash it would take to fdl up one standard size office garbage can). In general, there should be no visual evidence of dumping. Noxious weeds My nobous or nuisance vegetabon which may Noxious and nuisance vegetation constltute a hazard to County personne!or the removed aa:ording to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and My evidence of contaminants or pollution such Materials removed and disposed of pollubon as oil,gasoline,concrete slurries or paint. according to applicable regulations. � Source control BMPs implemented'rf appropriate. No contaminants present other than a surface al film. Grasslgroundoover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Tank or Vault Trash and debris Any trash and debris accumulated in vautt or tank No trash or debris in vautt. Staage Area (indudes floatables and non-floatables). Sediment Accumulated sediment depth exceeds 10%of the All sediment removed irom storage accumulaGon diameter of the storage area for Y�lengtfi oi area. storage vault or any point depth exceeds 15%of diameter. Example:72-inch storage tank would require Geaning when sediment reaches depth oi 7 inches for more than%:length of tank. Tank Structure : Plugged air vent Any blockage of the vent. Tank or vault freely vents. � Tank bent out of My part of tank/pipe is bent out of shape more Tank repaired or�eplaced to design. � shape than 10%of its design shape. ; Gaps between A gap wider than Yrinch at the jant of any tank No water or soil entenng tank '� sections,damaged sections or any evidence of soil particles entering through joints or walls. jants or cradcs or the tank at a joint or through a wall. tears in walt Vautt Structure Damage to wall, Cracks wider than Yr-inch,any evidence of soil Vauft is sealed and structuralty I Frame,bottom,and/or entering the structure through cracks or qualified sound. top slab inspection personnel determines that the vault is not structurally sound. irleUOutlet Pipes Sediment Sediment filli�g 209'0 or more of the pipe. InleUoutlet pipes dear of sediment accumulation Trash and debris Trash and debris accumulated in inleUoutlet No trash or debris in pipes. pipes(inctudes floatables and non-floatables). � Damaged Cracks wider than Yrinch at the jant oi the No cradcs more than Y.-inch wide at � mleVoutlet pipes or any evidence of soil entering the joint of the inleUoutlet pipe. � at the joints of the inleVoutlet pipes �� 2009 Surface Water Design Manual-Appendix A 1/9/2009 A-5 APPE'�iDIX A MAINT'ENANCE REQUIREMENTS FLOW COtiTROL,CONVEYANCE,AND WQ FAC[L[TIES NO. 3- DETENTION TANKS AND VAULTS Mairrtenance I Defect or Problem Conditbns When Maintenance ts Needed Results Expected When Component Maintenance is Perfortned ' Access Manhde ' CoverAid not in place CoverAid is missing or only partialiy in place. Manhole access covered. ; My open manhole requiros immediate � mafntenance. i i Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. i not working mamtenance person with proper tods.Bolts � , cannot be seated. Self-locking covedlid does not �� ', Nrorlc. Cover/lid difficult to One maintenance person cannot remove CoveNlid can be removed and remove coverllid after applying 80 Ibs of lift. reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs,misalignment,rust,or cradcs. Ladder meets design standards. fUlows maintenance person safe access. Large access ; Damaged or difficult Large access doors or plates cannot be Replace or repair access door so it coors/plate � to open opened/removed using normal equipment. can opened as designed. Gaps,doesn't cover Large access doors not flat and/or access Doors Gose flat and covers access completely opening not completely covered. opening o�npletely. Lifting Rings missing, Lifting rings not capable of lifting weight of door Liiting rings sufficient to lift or rusted or plate i remove door or plate 7�L;�� __� --_ _- --------y-��-- - -._._��__��_ e_ ! y � �;)U �(Ir��: Su;ta;;e�',,t�r Crsi��n :�lanual ��Pendi�:A ,\-6 ll'?L\lll\ :A '�1.�[\TL-\."�ACL Ri:t1L IRI_A1LV"C5 FU[Z FLOt� (�l)\TRUL.L�.iA\L1:l\�E.:A\i) �V�t�� i=.1C�ILI�I_1 � N�. 4-CONTROL STRUCTUREJFLOW RESTRICTOR ; Maintenance Defect or Problem Conditlon When Maintenance is Needed Results Expected When Component � Maintenance is Performed SUucture T►ash and debris Trash or debris of more fhan Y:cubic foot which No Trash or debris blodcing or � is located immediately in front of the structure potenGally blocking entrance to opening or is bbcking capacity of the structure by structure. j more than 10°!0. j Trash or debris in the structure�at exceeds'/� No trash or debns in the structure. ! the depth from the bottom of basin to invert the i lowest pipe into or out of the basin. Oeposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breedng of insects or rodents. Sediment Sediment exceeds 60°l0 of the depth from the Sump of structure cantains no ' bottom of the structure to the invert of the towest sedimenL pipe into or out of the structure a the bottom of the FROP-T section or is within 6 inches of the ' invert of the lowest pipe into or out of the � structure or the bottom of the FROP-T section. Damage to frame Comer of trame extends more than'/.inch past Frame is even with curb. � andlor top slab curb face into the street(If applicable). ! Top slab has holes larger than 2 square inches or Top slab�s free of hotes and cracks. I cradcs wider tlian%.inch. Frame not sitting flush 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 walls or Cradcs wider than Y:inch and longer than 3 feet, Structure is sealed and structurally bottom any evidence of soil particles entering sUucture sound. through cracks,or maintenance person judges that strudure is unsound. Cradcs wider than Y:inch and longer than 1 foot No cracks more tfian'/.inch wide at at the joint of any inleUoutlet pipe or any evidence the joint of inleUoutlet pipe. of soil particies entering structure through cracks. Settlert�nU Strudure has settled more than 1 inch or has Basin re�aced or repaired to design misalignr�nt rotated more than 2 inches out of alignment. standards. ' Damaged pipe jants Cracks wider than'/rinch at the jant of the No cracks more than Y.-inch wide at i inleUoutlet pipes or any evidence of soil entering the joint of inleUoutlet pipes. � the sWdure at the joint of the inleUoutlet pipes. Contartanants and Any evidence of contaminants or pollution such Materials removed and disEwsed of potluti� as oil,gasoline,ooncrete slurries or paint. according to applicable regulations. Source control BMPs implemented if : appropriate. No contaminants present other tha�a surface oil film. Ladder rungs missing Ladder is unsate due to missing rungs, Ladder meets design standards and or unsafe misalignment,cust,cracks,or sharp edges. allows maintenance person safe access. FROP-T Section Damage T section is not securely attached to structure T secbon securely attached to wall wall and ouUet pipe sVucture should support at and ouUet pipe. least 1,000 Ibs of up or down pressure. Strudure is not in upright positi�(allow up to Strudure in correct position. � 10%from plumb). � � Connec6ons to outlet pipe are not watertight or Connections to outlet pipe are water � show signs of deteriorated grout tight;sWcture repaired or replaced � and works as designed. Any holes—other than designed holes--in the Structure has no holes other than sWcture. designed holes. Clea�ut Gate Damaged or missing Cleanout gate is missing. Replace cleanout gate. 2009 Surface Water Design Manual-Appendix A 1/9/2Q�:i4) A-7 ��. � APPENDIX A MAINTENANCE REQIl[RE;�fENTS FLOW CONTROL,COIv'VEYANCE,A?dD WQ FAC[LITIES NO. 4-CONTROL STRUCTURE/FLOW RESTRICTOR Malntenance Defect or Probiem Conditio�When Maintenance is Needed Results Expected When Component Maintenance is Performed I ( Cleanout gate is not watertight. Gate is watertight and wortcs as designed. Gate cannot be moved up and dovm by a�e Gate rtaves up and down easily and maintenance person. is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Orifice Plate Damaged or missing Control device is not working prope�ty due to Plate is in place and works as missing,out of place,or bent orifice piate. designed. Obstrudions Any trash,debris,sediment,or vegetation Plate is free of all obstructions and blocking the plate. works as designed. Overflow Pipe ObsVucflons My trash or debns blocking(or having the Pipe is free of all obstructions and potential of blodcing)the overflow pipe. works as designed. Defom►ed or damaged Lip of overflow pipe is bent or deiortned. Overflow pipe does not allaw lip ove�flow at an elevabon lower than design InIeUOudet Pipe Sediment Sediment filling 20%or more of�e pipe. InleVoutlet pipes dear of sediment. accumulaUon Trash and debris Trash and debris accumulated in inleVoudet No trash or debris in pipes. pipes(includes floatables and non-floatables). Damaged Cradcs wider than Yrinch at the joint of the No cracks more than'/.-inch wide at inleUa�tlet pipes or any evidence of sal entering the joint of the inleVoutlet pipe. at the joints of the inleUoutlet pipes. Metal Grates Unsafe grate opening Grate with opening wider than'/6 inch. Grate opening meets design (If Applicable) standards. : Trash and debris Trash and debris that is blocldng more than 20�o Grate free of trash and debris. of grate surface. footnote to guidelines for disposal � Damag�or missing Grate missing or broken member(s)of the grate. � Grate is in place and meets design standards. Manhole CovedLid CoverAid not in place Coverllid is missing or only partally in place. CoverAid protects opening to My open structura requires ur�nt structure. maintenance. " Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. Not Working maintenance person with proper tools.Bdts cannot be seated. Self-locking cover/lid dces not work. CoverAid difficult Fo One maintenance person cannot remove CoverAid can be removed and Remove coverRid after applying 80 Ibs.of lift. reinstatied by one maintenance person. - --_-- - ---��__ __.__ ._ t_-�,. _. _ --------— ---- - �___ �_. .,._.�. ��— ,_ 1 y _'UU�> _UU4 Surfacc`4 ater Des��n�'an��al :lppenci-: ;� n-� ?�C��- APPEh'DIX A MAI?JTENANCE REQUIREMEN'tS FOR FLOW COhTROL,CO':�IVEYANCE,A.�iD WQ FAC[LITIES NO. 5-CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When ComponeM Maintenance is Performed Strudure Sediment Sediment exceeds 609'0 of the depth from the Sump of catch basin contains no bottom of Uie catch basin to the invert of the sediment. lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Trash and debris Trash a debris of more than Y:cubic foot which No Trash or debris bbcking or is located immediately in front of the catch basin potenbally blocking entrance to apening or is blocking capacity of the catch basin qtch basin. by more than 10°�. Trash or debris in the catch basin that exceeds No trash or debris in the catch basin. '/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. ' Dead animals or vegeta6on that could generate No dead animals or vegetaGon odors that could quse complaints or dangerous present within catch basin. gases(e.g.,methane). ; Deposits of garbage exceeding 1 cubic foot in No conditlon present which woufd vdume. attrad or support the breeding of insects or rodents. Damage to frame Comer of frame extends more than'/.inch past Frame is even with curb. and/or top slab curb face into the street(If applicable). Top slab has holes larger than 2 square inches or Top slab is free of holes and cracks. cradcs wider than Y.inch. Frame not sitting flush on top slab,i.e., Frame is sitting flush on top slab. separaGon of more than'/.inch of the frame from the top slab. � Cracks in walls or Cracks wider than'/:inch and bnger than 3 feet, Catch basin is sealed and ; bottom any evidence of soil partiGes entering catch structurally sound. � basin through aacks,or maintenance person judges that catch basin is unsound. ,i Cracks wider than Y:inch and longe►than 1 foot No cxadcs more than'!.inch wide at �I at the joint of any inleUouUet pipe or any evidence the joint of inleVouUet pipe. j of soil partides entering catch basin Through �i c.rddcs. �� Settlementl Catch basin has settled more than 1 inch or has Basin replaced or repaired to design I! misalignment rotated more than 2 inches out of alignment. standards. ', Damaged pipe joints Cracks wider than Yrinch at the joint of the No cradcs more than Y.-inch wide at , � inletJoutlet pipes or any evidence of soil entering the jant of inleVoutlet pipes. the catch basin at the joint of the inleUoudet PiPes_ ,� ' Contaminants and Any evidence of contaminants or pollubon such Materials removed and disposed of pollution as oil,gasoline,concxete slumes or painL according to applicable regulations. � Source control BMPs implemented rf appropriate. No contaminants present other than a surface al film. ' InletlOutlet Pipe Sediment Sediment filling 20°�or more of the ppe. In�eUoutlet pipes clear of sediment. accumulation 'i i Trash and debris Tresh and debns accumulated in inleUoutlet No trash or debris in pipes. , � pipes(includes floatables and non-floatables). � Damaged Cracks wider than Yrinch at the jant of the No cradcs more than Y.-inch wide at ' inleUoutlet pipes or any evidence of soil entering the jant of the inleVoutlet pipe. ; � at the joints oi the inleUouUet pipes. ! 2009 Surface Water Design Manual-Appendix A l/9/2009 A 9 .��jj �r 1PPE�DI\A �1:\I�TE\:1\C[ RFQL�IRE�IE�TS FLO\� CO�TROL, CO�\"L1":��CF_:��D�1 Q F.�C�1L1-fILS � �� NO. 5-CATCH BASINS AND MANHOLES � Maintenance Defect or Problam Condition When Malntenance fs Needed Results Expected When � � ; Component Maintenance is Perfortned Metal Grates Unsafe grate opening Grate with opening wider than'/e inch. Grate opening meets desgn I li (Catch Basins) standards. � �, Trash and debns Trash and debris that is blocking more than 20% Grate free of trash and debris. ' I of grate surface. foomote to guidelines for disposal � Damaged or missing Grate missing or broken member(s)of the grate. Grate is in place and meets design � My open structure requfres urgent standards. j mairrtenance. � ' Manhole Cover/Lid ' CoverAid not in place Cover/lid is missing or only partially in place. Cover/lid protects opening to IMy open structure requires urgent sVudure. maintenance. 4 Locking mechanism Mecharnsm cannot be opened by one Mechanism opens with proper toots. Not Working maintenance person with proper tools.Bolts cannot be seated. Self-locking coveNlid does not Mrork. � � Cover/lid difficult to One maintenance person cannot remove CoverAid can be removed and � Remove covedlid after applying 80 Ibs.of lift. reinstalled by one maintenance aerson � 5 �ppS , -- _"_____ � ,;!09 Surface\�'atcr Dcsi��n .�'anual 4��rndix A -1-I 0 /�� APPEVDIX A MAINTENANCE REQliIRENIENTS FOR FLOW CONTROL,COiv'VEYANCE,AND WQ FACILITfES NO. 6-CONVEYANCE PIPES AND DITCHES Maintenance ' Defect or Prob{em CondiNons When Maintenance is Needed Results Expected When Component Maintenance is Performed Pipes Sediment&debris Accumulated sediment or debris that exceeds . Water flows freely through pipes. � accumulation 20°�of the diameter of the pipe. � VegetatioNroots Vegetation/roots that reduce free movement of Water fbws freely throu�pipes. � water through pipes. Contaminants and My evidence o(contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,cancrete slurcies or pain4 according to applicable regulations. Source control BMPs implemertted if appropriate. No contaminants present other than a surface oiI film. I' Damage to protecUve Protective coaong is damaged;rust or corrosion Pipe repaired or replaced. I coating or corcosion is weakening the structural integrity of any part of PiPe• Damaged My dent that decreases the cross sedion area of Pipe repaired or replaced. pipe by more than 20%or is determined to have weakened sVuctural integrtty of the pipe. Ditches Trash and debris Trash and�b�s exceeds 1 cubic foot per 1,000 Trash and debris Geared irom square feet of ditch and siopes. ditches. � Sediment Accumulated sediment that exceeds 20%of the Ditch cleanedlflushed of all sediment accumulation design depth. and debris so that it matches design. � Noxiars weeds Any noxious or nuisance vegeta8on which may Noxious and nuisance vegeta6on constitute a hazard to Counry personnel or the removed according to applicable , public. regulations. No danger of noxious vegetation where County personnel or the public mighi normally be. Contaminants and Any evidence of c�taminants w pollution such Materials removed and disposed of pollu0on as oil,gasoline,concrete slurries or paint. according to applicable reguladons. i Source control BMPs implemented if � appropriate. No contaminants present other than a surface oil film. Vegetadon Vegetation that reduces free movement of water Water flows freely through ditches. through ditches. Erosion damage to My erosan observed on a ditch slope. Slopes are not eroding. slopes Rodc lining out of One Iayer or less of rock exists above native soil Replace rocks to design standarda place w missing{If area 5 square feet or more,any exposed native Applicable) soil. —� - - _____ --- – _- '�ii�v ju,-f.i:c\1 :�:r-)c;i�n A'a�:�:.', �acr=�:i` � �urn: A-il ��` - - w APPENDIX A MAINTEIvANGE REQLiREMENTS FLOW CONTROL,CO:�tVEYANCE,AND Q FACILITIES NO. 11 - GROUNDS (LANDSCAPING) Maintenance i Defect or Probkm Conditions When Mai�tenance is Needed Resutts Expected When Component Maintenance is Perfortned Site Trash ot litter My trash and debris which exceed 1 cubic foot Trash and debris deared from site. per t,000 square feet(tnis is about equal to the , amaunt of trash it would take to fiil up one star�ard size office garbage can). In general, there should be no visual evidence of dumping. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation cansUtute a hazard to County personnel or the removed according to appliqble public. regulations. No danger of no�ous � vegeta�on where County personnel i i or the public might normally be. Contaminants and ; Any evidence of contaminants or pollution such Materials removed and disposed of pollution as al,gasoline,concrete slurries or paint according fo applicable regulations. Source control BMPs implemented"rf appropriate. No contaminants present other than a surface al film. Grass/groundcover Grass or�ndcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Trees and Shrubs Hazard Any tree or Iimb of a tree identified as having a No hazard trees in faality. potential to fall and cause property damage or threate�human life. A hazard tree identified by a qualified arborist must be removed as soon , as possible. ' Damaged Limbs or parts of trees or shrubs that are split or Trees ar�shrubs with less than 5% broken which affect more than 25%of the totai of total foliage with split or brolcen foliage of the tree or shrub. limbs. Trees or shrubs that have been blown drnm or No bbwn down vegetation ar knocked over. knocked over vegetation. Trees or shrubs free of injury. Trees or shrubs which are not adequately Tree or shrub in place and supported ar are leanmg over,causing exposure adequately supported:dead or �f!he�oo.s d:sease�trees•emo�.e� �� i I;�:n0�9 '_Or�� Su-fuc��z�atcr Dc,ien �vi3mr+l r+,PPen�lc. 1 '1-1ti \ `, M O D U L A R WETLANDS Maintenance Guidelines for Modular Wetland System - Linear Maintenance Summary o Remove Trash from Screening Device - average maintenance interval is 6 to 12 months. • (5minute average service time). � Remove Sediment from Separation Chamber-average maintenance interval is 12 to 24 months. • ( 10 minute ave�age service time}, Replace Cartridge Filter Media -average maintenance interval 12 to 24 months. • ( 10-75 minute per cartridge average service time). Replace Drain Down Filter Media -average maintenance interval is 12 to 24 months. • (5 minute a verage service time). _ Trim Vegetation-average maintenance interval is 6 to 12 months. � r Sen;��e ti.r..�� :;ar.ies� Svstem Diagram Access to screeni�g device, separation chamber and cartridge filter { ; �i ` `Ii � ,+ Access to drain � down fllter Inflow Pipe �� ` .� � , , �. (optional) --- , � -- ,; �,.,�� ` . .� , --� �•, _:: � , � Pre-Treatn �; : Chamber � � � Biofiltration Chamber + '} ' Outflow ''', �- Pipe ' Discharge Chamber www.modularwetlands.com 1 � � � . I _� M O D U L A R WETLANDS Maintenance Procedures Screeninq Device 1 Remove grate or manhole cover to gain access to the screening device in the Pre- Treatment Chamber. Vault type units do not have screening device. Maintenance can be performed without entry. 2. Remove all pollutants collected by the screening device. Removal can be done manually or with the use of a vacuum truck. The hose of the vacuum truck will not damage the screening device. 3 Screening device can easily be removed from the Pre-Treatment Chamber to gain access to separation chamber and media filters below. Replace g�ate or manhole cover when completed. Separation Chamber 1. Perform maintenance procedures of screening device listed above before maintaining the separation chamber. 2. With a pressure washer spray down pollutants accumulated on walls and cartridge filters. 3 Vacuum out Separation Chamber and remove all accumulated pollutants. Replace screening device, grate or manhole cover when completed. Cartridqe Filters 1 Perform maintenance procedures on screening device and separation chamber before maintaining cartridge filters. 2 Enter separation chamber. 3. Unscrew the finro bolts holding the lid on each cartridge filter and remove lid. 4 Remove each of 4 to 8 media cages holding the media in place. 5. Spray down the cartridge filter to remove any accumulated pollutants. 6 Vacuum out old media and accumulated pollutants. 7 Reinstall media cages and fill with new media from manufacturer or outside supplier. Manufacturer will provide specification of inedia and sources to purchase. 8. Replace the lid and tighten down bolts. Replace screening device, grate or manhole cover when completed. Drain Down Filter 1 Remove hatch or manhole cover over discharge chamber and enter chamber. 2 Unlock and lift drain down filter housing and �emove old media block. Replace with new media block. Lower drain down filter housing and lock into place. 3 Exit chamber and replace hatch or manhole cover. www.modularwetlands.com �1� ?� V✓ETLANDS Maintenance Notes 1. Following maintenance and/or inspection, it is recommended the maintenance operator prepare a maintenance/inspection record. The record should include any maintenance activities performed, amount and description of debris collected, and condition of the system and its various filter mechanisms. 2. The owner should keep maintenance/inspection record{s) for a minimum of five years from the date of maintenance. These records should be made available to the governing municipality for inspection upon request at any time. 3. Transport all debris, trash, organics and sediments to approved facility for disposal in accordance with local and state requirements. 4. Entry into chambers may require confined space training based on state and local regulations. 5. No fertilizer shall be used in the Biofiltration Chamber. � 6. Irrigation should be provided as recommended by manufacturer andlor landscape � architect. Amount of irrigation required is dependent on plant species. Some plants may require irrigation. � i www.modularwetlands.com '; ? ' t� _.��.--- M O D U � A � ��TL��C�� Maintenance Procedure Illustration __ . . q Screeninq Device � �- � � -�`` _-� - ` � �=� The screening deu; : � �` � �� under the manhole or grate over the - � �-� =�'� � Pre-Treatment Chamber. IYs mounted �� directly underneath for easy access and cleaning. Device can be cleaned by hand or with a vacuum truck. ,�.� g � -� � �§� � Separation Chamber --�. �,� �� , ��. �._ ��: The separation chamber i� Iauateu .�� a; �� '- " � :- �� :�.t- directly beneath the screening dev�c.e. �� -fi- � � `� It can be quickly cleaned using a ..� � _ vacuum truck or by hand. A pressure � {��;;��_ � :,- �s ,. � . � washer is use#u► to assist in the `} �� : �.= cle�n�ng �r�ces� �� , �r�, � ��. � , , � �` - � ____e_. �}� �.- . � , . . , �,, �� .. r -� .. ��t �� m= �� , �_ �� t .�, �r, � }_ ., I _ �4'� � �7. },' , ;-�, s�' "e` a^" j r �� .. ',� i ':-� www.modularwettands.com �+ \ M O D U L A R u/ETLANDS Cartridqe Filters The cart�idge filters are located in the _ Pre-Treatment chamber connected to the wall adjacent to the biofiltration chamber. The cartridges have ;;= removable tops to access the ,�_- individual media filters. Once the '�� cartridge is open media can be easily removed and replaced by hand or a vacuum truck. j� � {`r«�- '�i ip �. : i�� i�3it�:�3 `� �� r ',y`' _ ,.E�N '1 �` _ "= a'`� .- � �,; , �` f�s ` � , *��'_ .� � _ nt�r 4 �. .. �- ' � . - ::� _ M,�, +��'s;�+��, :��. �!� _ � _ � �„w��"+�,a-�,.-�s=-. �� {�"� 4 f � � � . '�,� �;.��7�` '� A,�+ i *,J�t� s � + � �*.,r. '� ` ��. ;+� T+at � �t •� `� � _ i ��b ��:- ' } � ` '�' _ �� `� � _�� `�_ � ;� � x _- � •3. �' ��'-�' - � - ` ' �_` � � � - �'. # �_ � ,a�'�= - • � -�� . �� ,��1 r.�� . � . � _ , ,�►, . ; ; ,,� : _ ��' Drain Down Filter The drain down filter is located in the Discharge Chamber. The drain filter unlocks from the wall mount and hinges . up. Remove filter block and replace with new block www.modularwetlands.com ''-i y� M O D U L A R �✓ETLA�IDS Trim Veqetation . .,` r, Vegetation should be maintained in the _ � E�i -� .��, same manner as surrounding vegetation .�,"� . ._�� : ' �, . and trimmed as needed. No fertilizer shall ' ' � ' :�_ � F be u r' �� sed on the lants. Ir i ation p 9 ., ,,�_. per the recommendation of the ' � manufacturer and or landscape � `��- '- architect. Different types of vegetation ��R` _ requires different amounts af � �; ;. '� ��: irrigation. - �� °�`� � � ;�:_''� t�. II I � �. , �.� � :�*- :;� �:�,.,�� _ � 3�= �;� �:� Yt � :�►f, � 4 , i y � I "�. I� �} ,� ,. ,� J �- �� ,: ,. � , . ,� , I �.�. � . .., � -. � l .' ."�,--�..�-,- .. _ y�. �t ' . 9.. }''� :-`, �'� � - � f � � �� a � , ��, � - , ;, ,I _ . � .��* . , x : . . . _ , . y. �g ,. . .: .A5�� li ... �t' .♦ ��c � � .�,�-.`4 i�.=. �'-�ti;t�`{ � '.;�' ) �,,,t� Y� ! �'S 4+.�'� ,�`��.�`�� 3 � ,°'��,f.��,.t�.4 T^�"� •�� fi;` ;`� www.modularwetlands.com �� ' _ V✓ETLANDS Inspection Form �� , �- � � _ _ � � .- . � .�=_ . . �' • i ° � . � . , r ,'� . '.1. `� . ' { 4 :�i. i �� Modular Wetland System, Inc. P. 760.433-7640 F. 760-433-3176 E. Info@modularwetlands.com www.modularwetlands.com �I� B�' �� CLEAN� �nspection Report � �.YIAOMM�biA( x,.r«<, ��z Modular Wetiands System u E�tANDS � F Vame For O�ce Use Onty P�o�ect Address t�r� tzw cc-�� {Rewewee By) Owner/Ma�agement Company _ iDate) OK�ce persa�rset!o compfete section to Contact Phone( ) — me�ert irspector Name Date / Time AM/PM T vpe of Inspection ❑ Routi�e ❑ Follow Up ❑ Complaint ❑ 5torm Storm Event m last 72-hours? ❑ No ❑ Yes v'deather Condition AddiUonal Notes Inspection Checklist ��4odular V'JeUand System Ty�pe (Curb. Grate o� UG vau:?i SiZe (22', 14'Or etC.): Structural integrity: Yes No Comments Damage to pre-treatment access cover(manhole covertgrate)or can�at be opened usi�g normal liftirtg pressure� Damage to d�scharge chamber access cover(manhole cover/grate)a pnnot be opened using normal lifting pressure? Dces the MWS unit show signs of structural detenoraUon{cracks in the wali.damage to frame)7 Is the inleUoutlet pipe or drain down pipe damaged or otherwise noi functionirtg property7 �1 �g Condition: Is there evidence of illicit discharge or excessive oii,grease,or other automob��fluids entering a�d doggmg th und? �is tnere standmg water m inappropnate areas after a dry penod� ,Is the fifter insert(if applipble)at capacity andior is there an accumulation of debris/trash on the�eH system? i Does the depth ot sedimenUtrash/debris suggest a bbckage of the i�flow pipe.bypass or cartndge filter? If yes �v�+ 'specify which one in the comments section. Note depth of accumulation in in pre-treatment chamber. cnamber j Does the cartr�ge filter media need replacement m pre-treatment chamber andlor discharge chamber? i Any s�gns of improper functioning in the discharge chamber? Note issues m comments section. 'Other Inspection Items: s there an accumulation of sedimenUtrashldebns in the wetland med�a(Ii applicable)? Is rt evident that the plants are alive and healthy(ii applicable)?Please note Plant Informatio�below Is there a septic or foul odor coming from inside the system? iWaste: Yes No Recommended Maintenance Plant Information �Sed�ment i SiR r Clay No CleaNng Needed Dama e to Plants ��rash I Bagsr Bottles Schedule Malntenance as Planned Plant Re lacement 'Green 11Vaste�Leaves�Fo�iage Needs Immediafe Mam?er.ance �� Plan?Tnmm�nq Aaoiuonal Notes 7G-^Ca � ._,-. . -�-�a,; ., oanci� . .. -;�=.�4 r.. , 4=�.. �..._ F 75��L?3 „ ,,, !. 7 1 V✓ETLANDS Maintenance Report � .� , ��T C-J a • �—z-�� ` �` aroc,4a Y t�'Rn+s+ ��s -� 4c,..• (7b0)433 7b�r � � ti ' - � < � � � .r � � ti � �� _ - � � 1:I .`.'�� ,� � ,: � � �y � `'�, , � �� ', � ��-� � ,► , � _ �' w �4 s {�� ' I :;� "7.;�i��1� ' . �t � ��`��ti �� i ` Y ' y� +� � �e \ `• f �••' �. q ` 4��4� � ��y�� -.�� `� r•`"�� . ` . `•`• ` \ t� ` ! II _t �� '�� L}.i�• ''Ti�. � �s}a k, �.l � `! \� �\ U� ��.�., ' . y .a �• � ,��. , �� •,• �,.�j �-j, �A;,. 'i..;h1 t 1��" � �§F � .. ,4� y.�x % �`�,� ', 4a �r,: �::"!� �' �°'��,j' ,��, �- `C �"- �`'�'r�`��. 1�# v � � ` �� 'tl�� `'`, ✓ '+!,\,� �� .`,, r �.� �� `�, �y �F `�!�; � �� s`-." �'`� � '`i',�?: `� � F �1 I +��.' � H t�',r��' ; , � 1 . r# , ,, }.. ,r�: - � . . {f a..:_ .'�,'- 1 '� a, ��ti �� ' ,r�j • � •""� �.�i, 1 �� a ��: �'1n ,��`'!l ,��e' �` `t �t +��';'� . �.. �i�'� �,y+ F � .,,� 'y t �� k� �� _ � r t y � �(r � � � �� lF �'!� t ,+i�� t��,� �� <� '�� tf�':'�V,. �+ ',�'j t` � � 5 S p� � '1:i �t 1 �-i � � �� '.�:�J,�L � 1 #� 't`t i �, .". - _f�� `. "� -_��t��.. ;;. .� ._ �, iY�. '�, '�► �� i� � '•Y•��.'l� j �.P� _�<E� 1. ). � �T_J '. • ✓�}t ��. A (;; ` ' �I' �I �ST . - � •.�. ` � p \� ' ti��s'��"�� /I��i�S��J� 'a Modular Wetland System, Inc. P. 760.433-7640 F. 760-433-3176 E. Info@modularwetlands.com www.modulanivetlands.com .; . �; , Cleaning and Maintenance Report `� a� � �`-�A� Modular Wetlands System � � M�� Q :.. YiRONME/�+T�( S:Av7Cf5.�NC. ltlC�1 t.�. r`C w G LH!+�.� Project Name For CN::,�U�t�n<y � I � Projec:t Address _ _ i ----- -- . , :- .._.. =ev+ras�t 3y; � � Owner!Man�ement Compa-r, i — – -- �---- — ,.,.a�e� � j ="3Kxa��r�r`r,k;sc c;t'�:cie s�c�,a.'�n S�( Co�tact Ph�ne( i — _��:n � Inspector Name Date 1 t Time =',_ ='�.' Type of InspecUion ❑ Routine ❑ �oi{ow Up ❑Comp�aint ❑Storm St�-T �;•er+ ��t'2-nnurs'' ❑ �;c (� r�s Weather Cond�tion Addibanal Notes Condition ot Media Operationai Per Site GPS Goordinates Manufac�urer! Trash Fo�iage Sediment 7otai Debrls 25�50175/1� ManufacUsres' Map# of Insert Qescription 1 Srzing Auumuiahon Accumulatian Accumulation Accum�lation {wiil be changed Specificatio�s �75%) {tt not,why�) �at: M W S , —______ Caich Basins ' Lo i MWS � -- Sedimentat�on Basin --- _ __ Media Filter Candition ' - - - Plant Condition __ _____ Drain �own Media Conciitton Discharge Chamber ______ _ ____ Condition Drain Down Pipe Condition ---_____ _ Inlet and Outlet Pipe Condition Comments; � � 2972 San Luis Rey Road,dceanside.CA 9205$P.760 433.7640 F,760.433 3178 ��