The URL can be used to link to this page

Home My WebLink About03681 - Technical Information Report L.; �. .� .� � � D. R. STRfJNG �M � �.'�� ' � , � , CONSULTING ENGINEERS � � , � . � �-- -----� �. ! ^.. `� i(10� � r� � FO . g - �..:.: �. _-- ---- __ ____ - -- � �v�� _.. ,� , � .... .... .... � �� z,� t3 - . . . , . . .- . - - . - - . - • : .;� �, '� % � DRAINAGE REPORT for PIPER'S BLUFF � 1166 Hoquiam Avenue NE Renton,Washington `� R �Ol; \�f OF �F.� G f r`� '� f .� /. S/ / I � �l I /! ~ �I l' f :i�LE�� ?. �� 1:�:j l l L F' �`.� � ��'I��L � � � �� /� „ � DRS Project No. 12029 Renton File No. LUA12-076, ECF, PP OwnedApplicant WestPac Development, LLC 7449 W Mercer Way Mercer Island, WA 98040 Reporf Prepared by - , • ! D. R. STRONG Consulting Engineers, Inc. 10604 N.E. 38th Place, Suite 232 Kirkland WA 98033 (425) 827-3063 ; Issued August 29, 2012 Revised January 31, 2013 . Revised April 29, 2013 �2012 D. R. STRONG Consulting Engineers Inc. DRAINAGE REPORT _ PIPER'S BLUFF TABLE OF CONTENTS � SECTION 1.......................................................................................................................1 ProjectOverview..........................................................................................................1 Predeveloped Site Conditions......................................................................................1 Developed Site Conditions...........................................................................................1 Natural Drainage System Functions.............................................................................2 SECTION11....................................................................................................................11 Conditions and Requirements Summary....................................................................11 SECTION111...................................................................................................................13 Off-Site Analysis.........................................................................................................13 SECTIONIV ..................................................................................................................14 Flow Control and Water Quality Facility Analysis and Design....................................14 Existing Site Hydrolo9Y �Part A)..............................................................................14 Pre-developed Hourly Time Step Modeling Input: ..................................................15 Pre-developed Hourly Time Step Modeling Output:................................................15 Developed Site Hydrolo9Y (Part B).........................................................................17 Developed Site Area Hydrology..............................................................................17 Developed Hourly Time Step Modeling Input:.........................................................18 Developed Hourly Time Step Modeling Output:......................................................18 Performance Standards (Part C)................................................................................20 Flow Control System (Part D).....................................................................................20 Flow Control BMP Selection ...................................................................................20 Flow Control Facility Design Output........................................................................22 Water Quality Treatment System (Part E)..................................................................28 SECTIONV ...................................................................................................................30 Conveyance System Analysis and Design.................................................................30 SECTIONVI ..................................................................................................................36 Special Reports and Studies......................................................................................36 SECTIONVII .................................................................................................................36 Other Permits, Variances and Adjustments................................................................37 SECTIONVIII ................................................................................................................38 ESC Plan Analysis and Design (Part A).....................................................................38 SWPPS Plan Design (Part B).................................................. ........38 ........................... :�:2013 D. R. STRONG Consulting Engineers Inc. Piper's Bluff Plat Page i of ii Drainage Report C;ty of Renton SECTIONIX ..................................................................................................................39 Bond Quantities, Facility Summaries, and Declaration of Covenant..........................39 Stormwater Facility Summary Sheet..........................................................................40 SECTIONX ...................................................................................................................42 Operations and Maintenance Manual ........................................................................42 � List of Figures Figure1 TIR Worksheet...................................................................................................3 Figure2 Vicinity Map .......................................................................................................6 Figure 3 Drainage Basins, Subbasins, and Site Characteristics......................................7 Figure4 Soils...................................................................................................................8 Figure 5 Predevelopment Area Map..............................................................................15 Figure 6 Post Development Area Map...........................................................................18 Figure 7 Detention & Water Quality Facility Details .......................................................29 Figure 8 Backwater Analysis Map..................................................................................35 Appendices Appendix A— Stormwater Pollution Prevention Plan .....................................................43 � � 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page ii of ii Drainage Report City of Renton SECTION I PROJECT OVERVIEW The Project is the subdivision of four existing parcels zoned R8 into 28 single-family residential lots, per the City of Renton's (City) subdivision process. The Tax Parcel Numbers are 102305-9367, 9312, 9002, and 9144. The Project location (Site) fronts on the east side of Hoquiam Avenue NE, at 1166 Hoquiam Avenue NE. One detention pond and a Stormfilter is proposed to serve the subdivision. The Project will meet the drainage requirements of the 2009 King County Surface Water Design Manual (Manual), as adopted by the City. PREDEVELOPED SITE CONDITIONS Total existing Site area is approximately 217,369 s.f. (4.990 ac). Total proposed Project area is 216,966 s.f. (4.981 ac), which includes 10,337 s.f. (0.237 ac) for the right-of-way frontage improvements on Hoquiam Avenue NE and excludes 10,740 s.f. (0.247 ac) of Tract "B" (NGPA). The Parcels are currently developed with two single-family residences, three out buildings and gravel driveway. The remainder of the Site is lawn, landscaping, scatter trees, moderately dense forest and underbrush. For the purpose of hydrologic calculations, the entire Site is modeled as till forest. DEVELOPED SITE CONDITIONS The Project will create 28 lots with lot sizes ranging from approximately 4,500 s.f. to 5,725 s.f. All existing improvements will be demolished or removed during plat construction. Two 16-foot wide alleys are proposed for Lots 1 to 17 for garage access. The 28 single-family residences combined with their driveways and alleys will create approximately 86,988 s.f. (1.997 ac) of impervious area. The proposed 45-foot right of ways will be improved with 18 feet of pavement, vertical curb, gutter, 8-foot planter strip, 5-foot sidewalk and a 8-foot parking lane on one side. The proposed right-of way adjacent to north property line will be 33-feet wide and will be improved with 15 feet of pavement, vertical curb, gutter, 8-foot planter strip, 5-foot sidewalk and a 8-foot parking lane on one side. The half street frontage improvements on Hoquiam Avenue NE will be improved with the required pavement width (approximately 12.80 feet) to provide 36 feet of pavement face of curb to face of curb, vertical curb, gutter, eight-foot planter strip and a five-foot sidewalk on the east side of Hoquiam Avenue NE. The 20-foot wide joint use driveway Tract "D" will be improved with 18 feet of pavement to serve lots 27 and 28. The improvements from right-of ways and joint use driveway tract will add 45,020 s.f. (1.034 ac) of impervious surFace. The paved access to detention facility and sewer lift station in Tract "A" will add 6,041 s.f. (0.139 ac) of impervious surface. The Project will result in a total of 138,049 s.f. (3.169 ac) of new impervious surfaces. The remainder of the developed Site 78,917 s.f. (1.812 ac) will consist of landscaping and lawns. The Project is required to provide Basic Water Quality treatment and Level 2 Flow Control, per the 2009 KCSWDM (Manual}. All surface water runoff from impervious surfaces will be collected and conveyed to a storm detention pond and media filter located in Tract "A. A 96-inch diameter Stormfilter manhole will be located downstream of detention and will provide 0.22 cfs of treatment flow rate. See the attached Contech 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 1 of 43 Drainage Report City of Renton Stormwater Solution, Inc, design details in Section X. The vault detention volume required is 69,132 c.f. and provided is 71,895 c.f. with 14 ft. of live storage depth. NATURAL DRAINAGE SYSTEM FUNCTIONS The Site is encompassed within one Threshold Discharge Area (TDA). The Site topography slopes generally to the east and northeast at approximately 2 to 15%. The vegetation consists of lawn, landscaping, and scattered trees in the house areas towards the southwestern and western regions of the Site. The remainder of the Site is � heavily vegetated with native grasses and shrubs, berry bushes, and moderately dense forest. Site runoff travels northeasterly and enters a Category 2 Wetland located near the northeast property corner and then exits to north via Class 4 Stream which is also located adjacent to the wetland near the northeast property corner. A review of the SCS soils map for the area (see Figure 4, Soils) indicates Alderwood gravelly sandy loam with 6 to 15 percent slopes (AgC) and Alderwood gravelly sandy loam with 15 to 30 percent slopes (AgD). Per the Manual, this soil type is classified as "Till" material. The SCS Soil series descriptions follow Figure 4. In evaluating the upstream area, we reviewed the existing offsite analysis and King County IMAP aerial topography and imagery and conducted field reconnaissance and have concluded that upstream tributary area for the Site is negligible. , ( , � � , �._- � � � ; 1 4 � � ��, l '� �_ ; � 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 2 of 43 Drainage Report City of Renton FIGURE 1 TIR WORKSHEET King County Department of Development and Environmental Services � TECHNICAL INFORMATION REPORT (TIR) WORKSHEET � Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND PROJECT ENGINEER DESCRIPTION Project Owner: Project Name: WestPac Development, LLC Piper's Bluff Address/Phone: Location: 7449 W Mercer Way Township: 23 North Mercer Island, WA 98040 Range: 05 East Section: 10 Project Engineer: Luay R. Joudeh, P.E. D. R. STRONG Consulting Engineers Inc. Address/Phone: 10604 NE 38�' Place, Suite 101 Kirkland WA 98033 (425) 827-3063 Part 3 TYPE OF PERMIT Part 4 OTHER REVIEWS AND PERMITS APPLICATION � Subdivision ❑ DFW HPA ❑ Shoreline ❑ Short Subdivision Management � Clearing and Grading ❑ COE 404 � Rockery ❑ Commercial ❑ DOE Dam Safety � Pond with Structural ❑ Other: Retaining Walls - ❑ FEMA Floodplain ❑ Other: ❑ COE Wetlands Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community: Renton Drainage Basin May Creek 02013 D. R. STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 3 of 43 Drainage Report City of Renton Part 6 SITE CHARACTERISTICS ❑River: ❑ Floodplain � Wetland � Stream: ❑ Seeps/Springs ❑ Critical Stream Reach ❑ High Groundwater Table ❑ Depressions/Swales ❑ Groundwater Recharge ❑ Lake: ❑ Other: , ❑ Steep Slopes Part 7 SOILS �, Soil Type: Slopes: Erosion Potential: Erosive Velocities: Alderwood 6-15% Slight Slow (AgC) Alderwood 15-30% Slight Slow i (AgD) � �Additional Sheets Attached: SCS Map and Soil Description, Figure 4 Part 8 DEVELOPMENT LIMITATIONS REFERENCE LIMITATION/SITE CONSTRAINT � Level 1 Downstream Anatysis None � Geotechnical Engineering Study � Environmentally Sensitive Areas ❑ Level 2 Off-Site Stormwater Analysis � Level I Traffic Impact Analysis � Structural Report ❑ Additional Sheets Attached Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION �Sedimentation Facilities �Stabilize Exposed Surface �Stabilized Construction Entrance �Remove and Restore Temporary ESC Facilities �Perimeter Runoff Control �Clean and Remove All Silt and Debris �Clearing and Grading �Ensure Operation of Permanent Facilities Restrictions �Flag Limits of SAO and open space �Cover Practices preservation areas �Construction Sequence ❑ Other ❑ Other �2013 D. R. STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 4 of 43 Drainage Report City of Renton Part 10 SURFACE WATER SYSTEM ❑ Grass Lined ❑ Tank ❑ infiltration Method of Analysis: Channel � Pond ❑ Depression KCRTS � Pipe System � Energy Dissipater ❑ Flow Dispersal Compensation/Mitigation ❑ Open Channel � Wetland ❑ Waiver of Eliminated Site � Dry Pond � Stream ❑ Regional Storage ❑ Wet Pond Detention N/A � Brief Description of System Operation: Runoff from impervious surfaces will be collected and conveyed to the detention facility. From there it will be discharged near the existing wetland located at the Site's northeast corner. Facility Related Site Limitations: Reference Facility Limitation Part 11 STRUCTURAL ANALYSIS Part 12 EASEMENTS/TRACTS ❑ Cast in Place Vault � Drainage Easement � Retaining Wall � Access Easement � Rockery > 4' High � Native Growth Protection Easement ❑ Structural on Steep Slope � Tracts ❑ Other: ❑ Other: Part 13 SIGNATURE OF PROFESSIONAL ENGINEER I or a civil engineer under my supervision have visited the site. Actual site conditions as obser�ved re incor orated into this worksheet and the attachments. To the best of m c�ow ge he inf 9fimation provided here is accurate. � �:: / �f��.--. � �� i/� Si ned/Da e � � '� :,2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 5 of 43 Drainage Report City of Renton FIGURE 2 VICINITY MAP � , . F ; �.v - � _ i�l�x�l►a�r. , r� .. _._.___ __ _ :� -- � �I� - „�, F NE�.�ttl-ST -- �'��o � . _,�, ' t . � , ._ ''� . � 1 ' ' q'�..�'�C,�: ��.PL.-; ..!f�. .. �, � ...:� hE21�T 8�1' . . .- �1,� �� I . t u i . ' . � a z,! �r' � a �� :�`�••�1�: �x,sT s� '� � '. x �� i I ,i q +�,Eats.�� i �. I i +r��n,sr,. ; , �t . , tie rsm s�r � � '�� ,� � x�e�sr. �� ' - - , ; ' � r , r . . � � , �� : �� : Iii�,yr�aT 8q: 'g `� � r ��, � /�.. ��-ti.�?. � .t�'. :�i � r��ezNc� � � "h� '�3+ � MB Y7TM�M,f!_ ��-_ , <. � N�1��- � x( c � �� . .. � � i "�em�+� f,� _ ; �,, -,i ,�, *z`` rr��rnsr � �ror►hsr -�{;u i I� _ __ �„s� elsr s-r , �' -_ ' �, . - �': - �;. � � '� - �.N-'" j f - `�� ".�_# �a,..�, � d' �?P` s�t��•� �.-�' �'�.�----. � ;� ' SITE � �,-�:`�� _� W ' � �r�" ' y+ �•, _S ME13hlR. liayVaDfayA�r?F I � _ ! e _ � , �-- , �t.irK RA� ', s '4 ,u � �,f-- SZ.� lfsf?�{g'�' � I+Et2TTfST�� I � _ -' �f � �'. .-r 17i}t i; I� �` = Rentan ��. s��,z,H� ! �s _ s�r,�sr� � � �;;,�, � � a rt.mssr ,� uE t trk sr � S� *�x��n:ar '�!� � _ � � � i i { _,..�' t �-' . �I a � �si,Tnar _- _ „mrst sErrerr+ar _ x. „i� d t �_ ,.,� �, � vE rnrH e� <� �;` i�i az,rr�� -- _ -�` w : �; �� : _ �,�„� a� w �E: � a t � i 3�:_ nrE an+sr W a .� ..�..�� s�itqmsT � � .�v. _ � y �� f .� , � .� . a . �� : : 4 - o � .�g,.,a , r._i . � _ .�. � � /, ,�m.a-r t� . � .MECryt9T . .. ., i� ��:�,- tIsYT}tST ��: .. � � �:r � . .. .. ..._... � �� Mf.fif7t CT . / � ti`r1. . _ a . � �:� �� ,f� _ ' �-.. , �"' .I'I� -..�NE HT1f P[ ':`.y;Y -:�"^�� : p{ Y !f!allf$T . � s � 1.� ��. NT..ii7'H 5k1' �. � �. � _, � ' _ .... ,�� ?iE71?tR'� � i�i. .. L~j,� ; _ � it�7fH�'T ir� 1 . � .. , � � , ��,____:. ' -- s��m � � .: � NETnrri. w .� 'i' �E- , • ' , � m ; ��t .:_�+6�Her�, tj � `z � � : , � HC,47NtY ��.�� ;, , ._�:,.� ; � � ; ;; :uetTkGT , .`� .-_...1� _� � - � _- ;� � '_. a d -� G� .�an+rr ' ; � � 'js�( .-�. �C�-2D�ercnq ca.,ntl- -- . .. .��".-.�_».,....� --- - -- '._ ._, _ � . __.. -- -a ---� - - �- '-i 996E " � `+ .�Y"� � .:- The information included on this map has been compiled by King County staff from a variety of sources and is subject to change without notice. King County makes no representations or warranties,express or implied, as to accuracy,completeness,timeliness, or rights to the use of such information. King County shall not be liabie for any general, special, indirect, incidental, or consequential � damages including,but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map.Any sale of this map or information on this map is prohibited except by written permission of King County. C2013 D. R. STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 6 of 43 Drainage Report City of Renton FIGURE 3 DRAINAGE BASINS, SUBBASINS, AND SITE CHARACTERISTICS , �2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 7 of 43 Drainage Report City of Renton � � .o.. _ - - W . 1 I � : - - : . - =-c - _._ _ �E � � �?_:�,._-' �c 2 , _ , -.� ; ------- I . �_ ._ . ' , � ' , - c - .. �_ __.._ ._�� __._ _ . W , , ` y � ,..- : °.a :x. : � � : . . _ . � ��e ' �-__— � X ' �X , DEVELOPED DlSCNARGE FOR TNE c� c� � � ` � _ -_ — �-�� ;� ` � , ` - SlTE FLOWS 1NT0 AN EX. WETLANG � � � � � � — — ---�— — _ , ; __ i � A�q _ THROUGI� THE STORM SYSTEM � � � „ 's54\ .. /�2 .ty� _ s �I�O� ` �h— y rt _ � � . 2 W Y -F- 1 ,� ., � ._...'. _ -..._ ..... `- , , � � _ _n _ ro�`y. ' . : - . - � - _ , p Fe y . ...� � , ._... . : _ -_ :-, _.. -}_. _ - ...-..�. _.. � , . ' ,. .'y-:__ -.._ .. � :� �, � 4 . . _: —.- ' .-_.. 0 _ ._ _. -- _ . ------`' �._ . " S EXI T THE SI TE � a r , _��: ___ __.._ � � � z _� . � tr - . _ _� A EET �OW. CONSTRUCTION � � � , r t. ' • ; __— _ , \ , : ,,_- � ' - - y `� . s i . -- FIGURE 4 I SOILS SOY A1eP�—p�8�Y�.W ashns�n ��, p � II ScS:=:'. Si35N EZ1�.< =�.19&' '� iEaJa. 5510✓J 5r1:LfD GfNGBO fi8110U YM110 �.�11' m5ow i` >it � � � _ �=. : �_ —n ----- ' s , — ---.. — -- _ — — _ _ _ o � � , ` � x � r �� _ ��: �. � �- _ � - � I - � I � �� _ � � _�� ; � �. � � � - I ��2 �`�_ - � I � =� � , _ .,��;��- � � 7, � ;�- .� _ �,.� ., � �' ��`� �"'��.: / �'� ra ' i .�� f�.�. _ t�> ■ i � � -- ' - � �� i i� , � i - ��.: �,s„ _ � arwa - - � [r�e I5�m sbn.w �ra 5a�al sr.�oao e6mm neaao saurn s�ei�o 56�tm I � . �c5we:�:iPeu[vweeaenRsmps•ii�-�� txias � q A o '� �� ,� � � ��` SITE � I�II �_' Cmssvdldf 8eMts Nazaiat Coopxa4v�Sail Si"veY Pa�ge11 a 3 i AgC—Alderwood graveliy sandy loam, 6 to 15 percent slopes I Map Unit Setting � Elevation: 50 to 800 feet Mean annual precipifafion: 25 to 60 inches li . Mean annual air temperature: 48 to 52 degrees F ' ` Frost-free period: 180 to 220 days li � Map Unit Composition ( Alderwood and similar soils: 95 percent �'�I Minor components: 5 percent , � ` Description of Alderwood � Setting Landform: Moraines, till plains �I Parent material: 8asal till with some volcanic ash � I G2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 8 of 43 � Drainage Report City of Renton Properties and qualities Slope: 6 to 95 percent Depth to restrictive feature: 24 to 40 inches to dense material Drainage class: Moderately we!!drained Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately !ow (0.00 to 0.06 in/hr) Depth to water fable:About 18 to 37 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Very low (about 2.5 inches) Interpretive groups Land capability (nonirrigated): 4s Typical profile 0 to 12 inches: Gravelly sandy loam 12 to 27 inches: Very gravelly sandy loam 27 to 60 inches: Very gravelly sandy loam Minor Components Norma Percenf of map unit: 1 percent Landform: Depressions Bellingham Percent of map unit: 1 percent , Landform: Depressions Seattle Percent of map unit: 1 percent Landform: Depressions Tukwila Percent of map unrt: 1 percent Landform: Depressions Shalcar Percent of map unit: 1 percent Landform: Depressions AgD—Alderwood gravelly sandy loam, 15 to 30 percent slopes Map Unit Setting Elevafion: 50 to 800 feet Mean annua!precipitafion: 25 to 60 inches 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 9 of 43 Drainage Report City of Renton Mean annua!air temperature: 48 to 52 degrees F Frost-free period: 980 to 220 days Map Unit Composition Alderwood and similar soils: 100 percent Description of Alderwood Setting � Landform: Moraines, til!plains Parent material: Basa/till with some volcanic ash Properties and qualities Slope: 15 to 30 percent Depth to resfrictive feature: 24 fo 40 inches to dense materia! Drainage c/ass: Moderately well drained Capacity of the most limiting layer to transmit water (Ksat): Very !ow to moderately !ow (0.00 to 0.06 in/hr) Depth to water table:About 18 to 37 inches Frequency of flooding: None Frequency of ponding: None Available water capacity.� Low (about 3.6 inches) Interpretive groups Land capability (nonrrrigated): 4e Typical profile 0 to 12 inches: Gravelly sandy loam 12 to 40 inches: Very gravelly sandy loam 40 to 60 inches: Very gravelly sandy loam C2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 10 of 43 Drainage Report City of Renton SECTION II CONDiTIONS AND REQUIREMENTS SUMMARY The Project must comply with the following Core and Special Requirements: • C.R. #1 — Discharge at the Natural Location: Runoff from the Site will discharge at the natural location which is near the Stream located at the northeast corner of the Site. • C.R. #2 — Offsite Analysis: Analysis is included in Section III. The Analysis describes the Site's runoff patterns in detail. • C.R. #3 — The Project is located in the Level 2 Flow Control area. A detention pond will provide flow control as required. The Project is required to match durations for 50% of the two-year peak flow up to the full 50-year peak flow. Also match developed peak discharge rates to predeveloped peak discharge rates for the 2-year and 10-year return periods (KCSWDM, Sec. 1.2.) Furthermore, the Project must meet the Flow Control BMP requirements as specified in Section 1.2.3.3 of the Manual. The Project will utilize the reduced impervious surface credit to meet this requirement. • C.R. #4 — Conveyance System: New pipe systems and ditches/channels are required to be designed with sufficient capacity to convey and contain (at minimum) the 25-year peak flow, assuming developed conditions for onsite tributary areas and existing conditions for any offsite tributary areas. Pipe system structures and ditches/channels may overtop for runoff events that exceed the 25-year design capacity, provided the overflow from a 100-year runoff event does not create or aggravate a "severe flooding problem" or "severe erosion problem" as defined in C.R. #2. Any overflow occurring onsite for runoff events up to and including the 100- year event must discharge at the natural location for the project site. In residential subdivisions, such overflow must be contained within an onsite drainage easement, tract, covenant or public right-of-way. The proposed conveyance system was analyzed using the KCBW program, and is capable of conveying the 100-year peak storm without overtopping any structures or channels. (See Section V). • C.R. #5 — Erosion and Sediment Control: The Project provides the nine minimum ESC measures. • C.R. #6 — Maintenance and Operations: Maintenance of the proposed storm drainage facilities will be the responsibility of the City. An Operation and Maintenance Manual will be included in Section X. • C.R. #7 — Financial Guarantees: Prior to commencing construction, the Applicant must post a drainage facilities restoration and site stabilization financial guarantee. For any constructed or modified drainage facilities to be maintained and operated by the City, the Applicant must: 1) Post a drainage defect and maintenance financial guarantee for a period of two years, and 2) Maintain the drainage facilities during the finro-year period following posting of the drainage defect and maintenance financial guarantee. 02013 D. R.STRONG Consulting Engineers Inc. PipePs Bluff Plat Page 11 of 43 Drainage Report City of Renton • C.R. #8 - The Project is located in the Basic Water Quality Treatment area. A 96- inch diameter Stormfilter manhole is proposed to meet this requirement. • S.R. #1 — Other Adopted Area-Specific Requirements: Not applicable for this Project. • S.R. #2 — Floodplain/Floodway Delineation: Not applicable for this Project. • S.R. #3 — Flood Protection Facilities: Not applicable for this Project. ' • S.R. #4 — Source Control: Not applicable for this Project. G2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 12 of 43 Drainage Report City of Renton SECTION III OFF-SITE ANALYSIS An offsite Level One Downstream Analysis was prepared by D.R. STRONG Consulting Engineers Inc. and is included in this Section. , , , I � ' I II I 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 13 of 43 Drainage Report City of Renton LEVEL ONE DOWNSTREAM ANALYSIS for PIPER'S BLUFF ' Preliminary Plat 1166 Hoquiam Avenue NE, Renton,Washington �� `� R �� ' �°�� F tva��r 1.lj�f ��S l �� .� �G � � ,�'o t , �i ,� 3216.. � � h'EGISC�i'•� ��}� �j��AL � I ! � DRS Project No. 12029 �; Renton File No. Owner/Applicant �� WestPac Development, LLC i 7449 W Mercer Way Mercer Island, WA 98040 Report Prepared by I , ' � �� D. R. STRONG Consulting Engineers, Inc. � 10604 N.E. 38th Place, Suite 232 Kirkland WA 98033 � (425) 827-3063 '� I � � ' Re o rt I II�I ssue Date p , August 29, 2012 02012 D. R.STRONG Consulting Engineers Inc. LEVEL ONE DOWNSTREAM ANALYSIS PIPER'S BLUFF TABLE OF CONTENTS ' TASK 1 DEFINE AND MAP THE STUDY AREA .........................................................1 TASK 2 RESOURCE REVIEW.....................................................................................5 TASK 3 FIELD INSPECTION .....................................................................................16 Upstream Tributary Area............................................................................................16 General Onsite and Offsite Drainage Description ......................................................16 TASK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS...17 Drainage System Description.....................................................................................17 DownstreamPath ...................................................................................................17 TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS.........................20 List of Figures Figure1 Vicinity Map .......................................................................................................2 Figure2 Site Map ............................................................................................................3 Figure 3 King County iMap Topography ..........................................................................4 Figure 4 Streams and 100-Year Floodplains and Floodway............................................6 Figure 5 King County iMap Wetlands...............................................................................7 Figure 6 King County iMap Erosion Hazard Areas ..........................................................8 Figure 7 King County iMap Landslide Hazard Areas .......................................................9 Figure 8 King County iMap Seismic Hazard Areas........................................................10 Figure 9 FEMA— Flood Insurance Rate Map.................................................................11 Figure 10 King County iMap Drainage Complaints........................................................12 Figure 11 USDA King County Soils Survey Map ...........................................................13 Figure 12 Downstream Map...........................................................................................18 Figure 13 Downstream Table.........................................................................................19 Appendix AppendixA Photos ........................................................................................................21 ��2012 D. R. STRONG Consulting Engineers Inc. Page i of i Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton TASK 1 DEFINE AND MAP THE STUDY AREA This Offsite Analysis was prepared in accordance with Core Requirement #2, Section 1.2.2 of the 2009 King County Surface Water Design Manual (Manual). The Site is located at NE 12th St & Hoquiam Ave NE, Renton, Washington. The Project is the subdivision of four into 30 single family lots. See Figure 1, Figure 2, and Figure 3for maps of the study area. �� . ' � �_i � '� ,I � , , l ; _ —, i � � II ; 02012 D. R.STRONG Consulting Engineers Inc. Page 1 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton FIGURE 1 VICINITY MAP SITE l� N=tnnrcu�� W � �,i �' �� ti� � � � , � ,; � � I� hE t 7Tri AJ,�' a . y � � RJ�+►`J t� i� NE1�TdrST • ;i $ �5 �' � � � � il , ;�; �� ti � ais5i�ra�sr I' � . _ p i :. NE'1-41'JI.ST � ' - ��__ __ y._. . � ., ,r0.'-- . __- _ _ ,., �; , . �'_-..� � � z \: '- .-- N f id'fipFL �`.IC?/ ��-'r<� m �1,� '-r'`1`,� � � g ~ •"1�_ - � �LSrt�� f� � a�-'- ��4 �._l �� - � � _�� 3� k�t317n W , }�<`'' Ma}r VaPlep P,arfir r • �J '--- 4�. '-i ----=,"` HFi�ri� r �� R,�l-�J ' G7 _-_� H612TlFST t , •`��, z � - � - } � ( � .j �. - � S_t t'dTJi ST � '� _ j ' �� '��'11?T�f P1 j � , i i Rent�n � � ;'� � . : k�i1TJfGT .. .� 1 �'113TFfST . NS11TIfST- I �'+, �i14TW�P1 � �. i— I� �r :! � ' _ 1 114T�Ft ST 5E 1 i4TFf ST ' 1 I� �� '�� ' �;y � ;u ;m t�sior��ai � �� _ � � � {, i� N�1�TH ST a mr �i i r� � N�1 a ` � �j � .�i � OTl�ST � ;y �� 11HTl1$T � �( � . < K '�I - k� e'� � c j1J��}yL N�9TlIF� � �' � . SEttiTHSI" —i� ' - p � 4 I c� ;1 2 iv�9TN�ST 5� ' aA"� I� , � N�t1Tii CT � 1 ' �- aFara�`� 0 9000ft {C)2449 Ming Covnty I i. q , The infoRnation included on this map has been compiled by King County staff from a variety of sources and is subject to change without notice. King County makes no representations or warranties, express or implied, as to accuracy, completeness,timeliness, or rights to the use of such information.King County shall not be liable for any general,special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map.Any sale of this map or information on this map is prohibited except by written permission of King County. 02012 D.R.STRONG Consulting Engineers Inc. Page 2 of 23 Level One Downstream Analysis PipePs Bluff Preliminary Plat City of Renton FIGURE 2 SITE MAP � 02012 D.R.STRONG Consulting Engineers Inc. Page 3 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton � I W 2 � I ! i�,='u:_.c__ z�T Z � A � I � ._<:_.s� - L- C9 C9 � 3 N H�•��,.� Z Z � � ^ �_ 4i I u,i-_<r<:;�o_ ?„�ce.�cr��'rqa I '-�: =*.3 O F� , .'�..� �I,` ��_ 4'7 CHA llll't�FiA^ �`; eJ �v:�r � � � � � ,C(:F rYC t- � ' � �-`- l x `� _}�__--I � �� • ` ` � � t .., �� v� �' x N , .-2�'`T�; � I �I ' z �e c a��v_kr � i � i \ 1 v 1'` .�' / ( i � � � w Y � ` -------_ �[ a cc-c p: �s�, • i /� i s, � cxa,xi_r,o•.a r _ I i�1'r 1 �1 (�) �� --- - ie�s cau_��s)_<„c�z - ' -------_____�r � ----� - � � / � \�♦ /� ` 1 `�74��JF�G^.. I 1 1 72 6V' S.8 4 Z Y � 2 � t� �t C: `'�l T2.�-�-�'-- � � 1 �' � `i_/ ¢ �y �'f = ♦'. _ 'l - -�*-,'7'7'4 F31.7 S' -----T-.�__" Z'l�4� ��` t N -' J •lk � �'\ � .1 � .., � ��--__.__ �� 1 Y7 t iSS:C - Q V �O � (_a IlAp a0XE5 �" I r � �� ,,,_.` ��'_ _ _'_ _ __--_ �_____ `-_ __ -_ . - � � 1 , l �. I` - 'F}F CtJI'Y' m -- '-- - - ' '- _ -_I_ �c-. -=ia�Aoi\ _ 1 � �'1�� f g � a s�'Fa�� , �=�e �.� _ _ r ss3. �, ; �y, �t�.� t � � � � % �G � y 4 w - 1�� \Y'��a'c . s ` --- " -- 'Cr -� � --` `-�r� .•��° Kr � � �-x � � � �*t1 � •e z i�-� , �///�)� W m N ' d i -n-r�� '� ( i3 ��c.' �� _ --_ _` �-_-=-_�.Y.,, -- -c= --�^ _J-� ��\ `� "�\ �� `� \ �\ `,, I�-'� // � ;i Ur..;f �\..�,�� 1 2 W p n.-�5�' 1 �;� -� r.. - ""` �_- --- -_ -�� __ \� � (�^ � �� ,r '\;� \�- \ � /� / ` \ t \ . .�1\��'.'� `/ V � 2 �H04Uf-A h1�Ac \` � y �. �J � T-� ��7- r'y_�` .Z._ -_. L_� t� �' _}�-<_ 1 \ � \' \• �� 11� S - 12'�b,C.C�Lr_kT��: i � � � � ^ - €, -� . . ��_ ^ � -�-` -` -,-_� ;'__�-___"-'tie` � . � r � �' ---- � w m IE a 4�2 3l. �,�i \ ' S 1�� B>p Fc34'. � Cr7f'-f'cc�L`i F E� rt�, \__\-�`_------1t'j �2 -�---�v 1 C-.-•-]__-r---� --L � _� r--\ -S�.i� �-� � o� , --�."" �" ` ..<E.O. Pf..;'"'.CCntiE3 if::�'s'.! � ��1E�'- �-' _ ''_'__'_, \ \ \ � '� --C- � �G= `-�c--._ _ �c � �� \ �-�_L=_ . '�' ca _ .-__ � �F.1�E LONC.S:CENrtL�C_.-- / ._EL>E'_^-_ . - -_--_ '. hi REC r'sau27 \� � � ` ki�i _;� 1 :?eta�utisa�ciFlFo \ � � ♦ \♦ � __._ \ � � . � � \ \��1` T � �` 2�� '1,}�[':-`c� � , s,nC.Ql?3 COh'.SW��' �I � � Y:1- �� A' � \\ \ \ \ \ � \ \ 1,_� `�` � \ ` �^� \� �.1'.�`\.". hETLA4C5 .. / "1 x 1 �C,YD, l �iY-�� \ \ 1 F� � � \ t \ J � i" _ ' 1 ♦ .t._'.� \ � �, 1 �V�� . !. •'�s \ ) :�'�-o Arcai.i^p \ \ \ b .�.'. �."' .k i�� > t� > � � _ � r�cr�c. � �/-�a��r]� � -,-_ � � � �•�.w � � iE��3..3..�Y�T 3 �� .1 I t0' ati., f5' _^T l �� ! �c�CJ. l � � �` { il�' ---(E' tCl��Q17AR '",2V+.� ay• '`� ,_ I L. .'I .- �11 \ �;.;• \ �.. \ ` \ � �\ ! � .,'�:" \ \ .� �A_ � � G.5 :F I.' �c..�, I� � � �h �� \ �y l �1��•'.A ` sA' 9 , � � �`�a B z - __ �� -�z� `� `` ;�� ♦ S ` .� 11 ___ 2- CONC CiiLYe.iT � .� �� .J);�i-G4'.� ��v^ � ) �...✓ `� \� \(� � � ♦ .\ �� ♦ �� \9;.�.�-i?':;.b. '� �` � \ \�..: e-�s3.a� o '",,�, ( � � r- i^•:._c.. i� ----- �� -�i .--� is-�c�. ` � � � `7'�,Z-� �` � ��'i� ��1. -� \ 1&•�4 �a /-( 1 \ � 'r�� t ", :t � to. \\ st��n�e 3 � � �� ! -S,�'1.C ��' 9'G•cCJ. / � \\ � �p��4 1 r�CJ. �\ \ \ \ �J � � � _ �� J � ` �, � ti��'��' ` . e•a;cxz '+�� c�H .an.07 ' � 1 � _(Z,c�� );,f.^�-�;?��"oet;o.� � 4/,�' � 'r� �':..� t � � �� ``a< �-�' �--.� \ =r.,g �F�, .�, �` 1=Ic � l`�7 >��7 � / I� \ g Ac'� E r' / - ✓' � .ki' l � � \ ♦ \ ��. _ r'-�.1,£„�, }l )� YG��.? \' �� \ :E 3'C"t� ��io . � O�C"\./ i �C=:`�Y OE�!�. � . T.T� 0.GD. � � � . �' 7:r•� y �. `l 7 .n.,, �\ ;-`> i� ,� �� ". \ � �` '-`� ` �. ` 1. �. . . �' s• ��. � . f F 2"^.�� =45i 77 �' � !0�'PcQ.1 I (( � 12 urtrJ ,L 1 y 1 d.�_'�;,p 'Q, .._L'F7.� , � 5 ��, 24 FLG��s% `t '� � 1 i6 H�dt � �.I..,y Y\ \ f) ` ��.. � J 'b..d' -., �� i�. [� � �4`}�� \ �� ! - � ¢ s�,r �� , � �.-� E� �n '�` z c c.r�uExr �j I r � � ` z� F„z �zt�H . r l`� �\ �..:,> ` ��y �� y�1'.� � �. � \'�;.� �t ��i_ ��-tFR �..n� � i � ,� �\` � :. _-:ea � _ - z ra?eci�. �-r', x_c �=�"t C,3 � � � t .u` u�.� �-� S 4B ' r� 1 i � � \ l � �j� � \ ♦ \ g`i 1 � ��A �� '. �i � I � � c_---�� . _ . 9'a�� ;"C�� ♦ ♦ �///'''aaa�� `✓ � \ � � t�At . ;;� 'tJ ` ; `�u j .� '�" t'- Sl \ t L'CG'4�.G7R.S{F,f I i ` 1\ `� � �j `� �S'J'1CIC. \ \ \ � �t � � � \ \ � � � � l � t N \ \ 1��•:; 5� i � i♦ �- � ` 1/'� `\ \ � �` ` Ti7 1 a r�a� .�:F I�, Cloi ' �-5� �1 `1 I_:a55.15 . � � ,. � F J:iO 1'V'n:a FiPE+4;'M1 �' i ♦ F[4hi i/2' t:�.R Hr� \ � c:f�' ,( � \� � � ,�� `�t-. ��^ � 1 \ 1� . � / l�5'iC G�STAHP:O � { i � YE_ON 7'C C ��`. 1� `[✓'� � ��`^-tIXD. \ � �'a ) �a r� ! c.i r' e' K} � i� ,� ___ .��' � \ LL.� � �.\ \[9�R�c7.•�: ��' � ��'�: / '?'`.�� . �,�(. � �4' FC'�\. ,� � ` ,1 7°'�Gi.G.d;�D PLASI� G �� '-7 ISc�' 0.4'S C� `� SiR_..�� :I�,..i t_�5;;". \ =.%0. ' / � ! 8n��...0. I O!l�'r.T � ��! � ♦ S \ "�-_ � �„` t1' �� / � ! W A-6 j` I i I i F� :.n�!E� � � _-_ � � A.� ` � �CI� \ \ � � �r� � ( I ! 1 i-•` Ci y�'_ IE_ .;:7.33 \\ i� _ ..�� '_ � / �r� � i / ' � _i ��. f�2�1�'.t7£p�. '^5� � J / � � / ( \ o _ TTPE• / r. II \ , G V l •\ j � \ HI, "J. ` � 1 ,I�".'L4/ / ,�a,�`4 P}.7 I I 2,4' C.,.�". L''� \ t,� � ` �` � � �'�,� �``�{ �;(" o£cl. � � � I �� `�ad-3"i*`-!{ ^� ��29 �.. o� J � �. �� HWSe rf c.i � ,� J ��1I ( ��v+�� fY.".Cu•. � q � �' j 9>V.c` 1 ` 4 � \ -, i ie is'ea.��y� � 9, � I : a��aex � � �-�i h'��1a � �I { ... r �' �� r '�,n �A=.� ' `` � �� o. �%+n� � �,�.s � �'Y�-:n � :€�e-:4r R � iE li CONC 51 e 5cq ' � 1 � . � S � � . 1 ( ' "` � �r'�\� ��x� � t "a � r; t e-�_.�• �'� �� \ ��i' i � :. .� r , YC' , �; :o� . � �.� . �� , �4��, , . A� . c � a F�itdJ 1;2'�'Rc RE2.4. � GR,t � �. 0 1 �B 6e"..A7. 4, r�i \ { �� \ \l ♦ 1� ! . \ � . / \ � i � � �g'p� � \ I � � e'�"' ♦ �:�� cz Ic� ' u2��.zD�E.Bti.o�v I vRFr. t ` �a� � ` \1�r'�� l0" ..!`h7� � ;Y•r�q: ;S� �o.� �.� � � � � -T � l �(3).z F�� cc.v 3 . .� �F4 f: � ;a *.. � a:..-n., . ��• � s„ � �;�. I,l� _ \� .-'� ,z �,�,. ��n:1_ �� 4 �� - � ---- ,.�-��-�. _ �` � � , �:� , i _ �� . ,° _ �. � �ltt�7 � 7 �,I S � 4. �i , \ '� ; \ ` 1{ \ \ -r.,�1\' � .'A�g•Fic� Z� \ -- ..� F_ 462. � f • ♦ _ `\GFA•.EL C4M:t.�T � � I ��, l J `��, tii G. � 4��F� � \ � � � t6"f v � � � r3'-'JE'SD� G.':'G �� . ti \ �{�� I 1 � � �� _ � �3+. 1 �/ ` S 3'.uE 10'D^'.7J. �,C=i x] 1 \ ♦ .Y,:'O. \ "r��s .\�z��aR ` ` ��FY.��i;��`'z�� .� - .� . n � eo r�oi�, � � � " -_, ,' - `?�-- _� ��r�^� ' -;: v 1�.�,,�, �°'��:��"y� \ en� .\ � � cl�tiS.D� ��. � ,_;,�y,.��\,`. --�1 r.-��?�`� � r��..��, Q N : �sl ' � '. ---c-- f.`i# 7'Sr�C; f/�-i'�� 5 � �.- ' �50 D^ ` 1 d�� L � '^ 3 R_ �..._..-. , �.I� 3 � f �;'.] \\� \(� �� .` '�.i_� r:'��J V`C..i � i�,� ``� -�---��>L�`�_�' '�t,g_.},��=��_f0.\� � �\� � \\ "�� k \ ` r vJ �\ k �`kk:' i F7UNJ 1� R 34� . \ 1 i \ " '^'�Y \' �r ii� �� T% � �� ,'� \� " �1 '.i ` � �� i -f� � _,r11 ��.. t u -��src a...� � re-y_.,r. � �` � � �\ � � .\ � . � �' � � ��, ` E ( \� L c1� \ \ \ � � � '� l W {�.,.,F:k � T I ' i ' r b \ � 1 \ 11 D }Sf�J 1.�E.,fi'. � \ • r l \ FR 1 I � � ' i �- !`r�J � � /�'��xe.i-_.c� -_�. � ll��oeaa. .� � � �� \ � �\ ��r° ��c; \ �, �.�. � � �� a � ��i� I I � 1 � E� �� \ \ \ � � \ a:J � r,�`.` � � t t - ��..;o. � � J � • � � � � \ \,c3,tr'� � Q � i � I�� \-r s:=e rr;c t¢);a/ra•�'c�. � Z,s�or;.�. \ � � � ` � � , i �\ �� =?�, � � Z W ��-„ E'i ZC�O. ♦ ♦ i['6JCi ti� � a � � i c"C�';:' PO t � -•--._...':'_ . �' �jl`c,��',..V. �>�ti; � � �, � \ �\ �♦ �? . t. `\ � ` � I \ tt 4 3`2 . i/r ' `, � b 6�J"� �t7. :1' �L� '�°`� � � ro'�-i'°• ��i'�,��:`�. c� �� `� �\ �\ �?�.,..�,:��,��u'Fy1`� `� � � � Q so.,�s na�t ,$c' �•� � ' ��-- . ...i r ,� � If stro r 1 ; (�e''��c� �� ai�'�f � � ,1•+''� � ` � �� 5:n`C�� i � f� �1.1 Rr•-o-�a.oz �� c� �J � e r_crn. �! � � � � � �� ✓ � , � � ie�e'co>::.(;�;_;c�.<� � o §;. J� �fF\ i<o�� lt:-�._-_�w-s-;-�:� � \ �--� ,. � �y�'� � � \ � yea�,-'is� � \� �, � C� � 1=ic";:L',:C(sj=e52G� �� O i'� y N:;c^ �il \511�5 ,� 1 � � \ \ '' ` ` � � --�e � ` � �:4�� j` �� 1, fn c�c1 k: � ♦ J '� `•\ � � � `\ \ :ry; `� 3e _,7�� 1 } �� MAll90'=- � __ I �/� �.� \ { � \ p \ \ � \ \ \ \ � i� '��- i -� � "� � \� ' � � � ^ \� � `\� �� v� \� `� l� � \ ,� \� \ �� 5:.{:��P��:��-.. - �'� , :1� � . � . . , � w ; °�:�- , , , � ` . � -. , '� J � . �;� ��. `y � ♦ _ \ � �` ` `� � \ � ♦ _ 1.,�� \ ,: _ �{f �r j:�.s e ? �,.` � \ ti � � _ � . '� i� - \ �`��=c� � '.2 �J i i�.^.n e ,.,i `� � FI..�CFOIe� ' _ n ` � \ �� \ ' \ �? ✓'fP7:I�v'G-'7-J. �� S�i. ` � � - 3 S yJ L- . � � ` _ f �.. \ 2L 8.�,J_GG. G�„�� .. `\ ` �l , � JIVcnT (7 3�' E � 21 O:;G`_. /�'�'� iQ' � 1l \j��"�� \ � 'w E � i.�7 _ �� .�f:_�� [ _... y� i i , \ l!' �„ \ ' �� 1�. �../`� \ ` 1 \ �' �/, V �� ' .. - --r --- � �_� !��±LO ! _-_ I ! \ �V�. � l�2 �� r.._. �;��o-o-� �ti� -\�;e � � � ;z'�s c,c.,� n �\ � � ► � � i � -. ___ -_ _ D F�,. _ ... ` . W �.� �.�__ ...V 's`2sG'�. �� ! `i _ 51 � r.; v � \\ �i�� C� �� f` < t�t.� -s� .. --� - � v , v i a•eze_c k, F, �,- ,�� ,��...�,C ar�u�. ��. ,�.� �� `� ,ti:\ «� � . I I ``1 L✓ " � ,. .\..�- .._l�r_ _.__. '�v �� ..� I ��>._ �� `\ ` \� (-)'�i .�.[..t ' =\ \ / C...irr�c. . � W ;� , __ . _ _ , �z.� -�:,. , , - r�� ,.� ` � � � � ,l 32'COvc. v, I `.� t . � ., �i I � > > ✓ � �e�:� `e' � F'_ �'.. .�6}��' �. � cUt��r � �, �\ � S. l.ti� N. 15' S.1�2, `.E.i/-.; r:i.�.?/4, i��.�� _�� 7�. [3-'. / � /i .. .} ,, t . tic-- � �- � ,_m t54Ei � �� i� �J • , 1ti FC-,:.� li2"R�A?N'.i •lY COt:C. �.! � 4- Ly .� '�._ \ l� , . � J / � i � � r�v:y FLt.S 0.'L4'EF2T �� L-- cr , IE a q5:,cc � ,' . t�� C ryY= C� ti`i'' � I� �,_� ,...c r-cs r.�,cxrce 72'CO,YC. \` �;��_PT T ,=� .��.03 I � , . I �4� � � N � RTH I ORAFTED BY.• OLR ' DES7GNED HY NAK I GRAPHIC SCALE PRO�ECT ENG1N£ER: LRJ � � 0 100 200 400 OATE• �.Q'S�Zp12 � i i PRO.ECT NO.: !1A?9 1 INCH =ZOO FT. R:\2012\G\12029\3\Drawings\Plots\?P\Report Fl�cres\07-3D5_FIG2.dwg 8/29/2012 3:24:48 PM POT FICURE.� 2 COPYRIC;-IT �02672, D.R. STRONG CONSULTING ENGiNEERS INC. FIGURE 3 KING COUNTY IMAP TOPOGRAPHY � � i 'I(:' -. . _�'��` N�t�}.��. NF iHTN ST ti�. . I7 -��aL�1D�" ' I� _ _t1��1 / ; ��`:,r � , � -- - ;�, i � � �... , _ � ,;� � � '� +��l , �J �'�ti . �� . � i i' ,, ' ��I I� --'� a - 1�� 1 1 -J � �~.. � � � � 47 . � ''1. V, . , I -�r � ~ �' � � � �� II ItI r / J ! ^ �' t � �S�`� li ' E I ;. � � 'S_ ,.�, ',\ � �'`� Q,. I ! �( , _ r r Ns,.�r�rw. ,Q� �'� �'E� �.�� _- ' I� , . r, _ ry ��, . �a .� � �� u�y3r,�,r j �I, _ . r �i' _ .,� 4 � . � i '�' � , Rentan �'`•�, , y��zrii sr�� . n5 tzr�r.�r ' SITE _ �, � � �'. ii �'� � � _. . �I / >t�' ( sst�ir�Rw: _ ' ''�, �i�: � ; . d �� . 'S� � �113'rf f ST w. � i � •�' - a �u �, q N�11TiiCT � � ! i( � �(�L � �i, z � NE 11THST ;.'� �`•� t � '� . _ . I� �.� HE 1a7?F Al' ''� jC�2�:�9 Ning Caunty 0 509ft " L�g�Rd � Highlighted Featurg Highways � Lak�es an.d Large RiYets '_� Gounty Batindary Streets �;/ Streams , ;� h4auntain Peaks - : wi�hway Gont�urs(5ft dark) r �: ArYcra]s ,�f 100:509:tOD0 taca7 �,ti;r �Oiher PaiC61S 02012 D. R.STRONG Consulting Engineers Inc. Page 4 of 23 Level One Do�vnstream Analysis Piper's Bluff Preliminary Plat City of Renton TASK 2 RESOURCE REVIEW • Adopted Basin Plans: May Creek Basin Action Plan was adopted in April 2001. • Floodplain/Floodway (FEMA) Map: No floodplains exist on site, See Figure 9. • Other Offsite Analysis Reports: None available at this time. • Sensitive Areas Folio Maps: See Figures 4-8 for documentation offhe distance downstream from the proposed project tothe nearest critical areas.lncluded, are sections of the King County Sensitive Areas Folio which indicate the following: • Figure 4 Strearns and 100-Year Floodplains and Floodway:There is a C/ass 4 Stream locafed near the northeasf property corner of the Site. There are no 100 year floodplains within one mile of the Site aJong the downstream path. • Figure 5 Wetlands:There is a Category 2 Wetland located near the � northeast property corner of the Site.There are mapped Wetlandswithin one mile of the Site along the downstream path. • Figure 6 Erosion Hazard:There are mapped Erosion Hazard Areas within one mile of the Site along the downstream path. ', • Figure 7 Landslide Hazard:There are no mapped Landslide Hazard ' Areas within one mile of the Site along the downstream path. � • Figure 8 Seismic Hazard:There are no mapped Seismic Hazard Areas within one mile of the Site along the downstream pafh. • DNRP Drainage Complaints and Studies:As shown in Figure 90,there are no ; drainage complaints within 1 mile of the Site along the downstream path. • Road Drainage Problems: None nofed. • USDA King County Soils Survey: See Figure 11. ' • Wetlands Inventory: Vol. 3South (1990) — The wetland inventory revealed no � additiona! wetlands within the downsfream path. I ; • Migrating River Studies: None are applicable to the site. i � , Washington State Department of Ecology's latest published Clean Water Act Section 'i 303d list of polluted waters: None listed along the downstream path. j ` • King County Designated Water Quality Problems: None at this time. I, , i • Adopted Stormwater Compliance Plans: None applicable to this site. i • Basin Reconnaissance Summary Reports: None available at this time � i +,_� , i , , 02012 D. R. STRONG Consulting Engineers Inc. Page 5 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton , i ' � , FIGURE 4 ' STREAMS AND 100-YEAR FLOODPLAINS AND FLOODWAY 1! �.4�Vi7 ,- . - _ 1J�ibt1.l,� OJ£1�sfST ; ,� �� JN��p1�.__ ��,: � � ' i _ ..��- 5. I}_-.-----`--' t� :ti =-: �-. � � , i :� ' .. y� ,' _ ��1� f J �L '�__'� �� w � � �ti _ ` - . � `�•—.---`—..�_ ' �� O: ' � a��.,.. �- � F 1�' �` .� . i,� *� `�P � � ��,SC��:". 4 �� .�'• it. � e � ME 1:1iii F�t � c�(Gt �.�'i+�` . (� � _ �� i . ( � , NE 13T!f ST . ; j I. , �' . . . . . ��. . 31 . � . I �,�� . - f�'entan `ti . . , �t 1?TFf ST � 7 ; , � __ � � � ' ' i �I ,y , SE'i1ZTIfPL . �� `\. f�1137it ST �i �i i � ' SITE � 1tE11TMCT � � �, 4 � � �: �� ; � ^ ��I z z rtE��rrrn sf ; � ! �� . i * ' . . . . . ? 5'� . . . II ,,,p !1 E 10Tti PL ��ti �CJ 2008 King Caunly • D 500ft L�ge nd � Highlightsd Fe�ture SAO Stre�rtt �_� County8ourtdarjl Jf c�szt �,� x Muiint�iri�'�aiss � Cdats2�a�nial HighiY.3}�S � CL�ss23almbni� $tr86tS � CLTss3 ! M�h� , Unc1�aHiod =_ .'? �� D l.akes and�..arge Rivers /,•-:. Local �f �$treams P�rCels � 104Ye�iFloodplaiYe � I I 02012 D.R.STRONG Consulting Engineers Inc. Page 6 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton �� FIGURE 5 � KING COUNTY �MAP WETLANDS ' LVD =. -:" �-=_� ��'�ttl]-!gf- NE 13i)I ST ,L i� _.��_a- . . '`.., � ' !' - - • : �' lil t ��.t � ti;�?� � � � � �� 1 � �-`_ � ,� � � --� ��<`�, �ti .? � � p , - '��,:- Y. , �, �� -. _'_� 'L��.`�� .. a � �a�°� , , I. � . `' i ,/��( � + . . },�7�5-� �t �� '�6t��\K s,�;}) 1 5 $. _ `�q� y ��.i. � Q ` N=17Th PL y'-�.y'� ti � T � S4f�� ti�s'�� , j l . ;��, 1��`�' _ _ _ - 't��"_ \� f�'�� I� ��{,t. ;;j HE 13T!}5T �� . ;�� : ��. � ,. . � ' Ren�o n �i ' !IE 12Tk ST I • ' F1F 12TH ST • � F �I � �*ti 55112TTf PL II � `� , �� '� � .�113�7i ST �; SITE a �: r,=�iTt�cT � � I a� � � � � ;I � i y � ME 11TfI ST . � �j �' � t'�.'ti, } �� .��a , Hc1�y�� ''S . -- �C)2098 Kmg Caunty 0 500ft � L��nd � Mghlighted F�ature -.r p,t� - I-� G�nunty Snitfida ry i«a1 y{ Mountain Peaks ParGelS Highways � Lakes and Large Riv�irs �{�g�� f Streants ' - ; Hqh.e�,y � ��10 iiYetland - (cont) I I I 4..-1 , ' � � 02012 D. R.STRONG Consulting Engineers Inc. Page 7 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton FIGURE 6 I KING COUNTY IMAP EROSION HAZARD AREAS � ��,. yao =_� ra��sr aE,errsr ,� '' �� gSNS�� i .. � '�. 4 14 �: - � ', i __ w ,r , c . - z �y .. � i�� ---,� -:.�L ' � !, i•~ �� _- . -••ti L_ r r�._, �`�� c�� a .. _� �' ;S � � p�}p�`.•. , �. �i `�._ ,... x � �s� L'7' �� . ,,'.; � ��'t� £4 � �I N�t�THx. � ` g�� '�� 4= - -- -. �r ' I i ' . �\ , :J813TH ST I I trE 1ZiH ST �,ento n ��''l� , � t . �� tlr 12TIt ST'� ,�i � ,. �h , � �� ; , SE i 121-►P P� , �� t x� SITE � s�ii�n�sr w � �' z � ' w r � rrsttrlrcT 'a � � �� ,; �; ;� .:� � � s�ts i�rr�sr �I "� . , . . `51�•� . . . . . i� .,a N�+orx at ,,: � ;C�2:q9 xing Caunty 0 5flDft � . � .. , . . Le�e nd � Highlighted Feature p,�� I-� �duhty BOundary L«al ,� hlountaln Peaks PaiCels Nighways � �1�es and Larg�Rivers streets f./ streams llighway SAO Erosi6n {cont} 02012 D. R.STRONG Consulting Engineers Inc. Page 8 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton FIGURE 7 KING COUNTY IMAP LANDSLIDE HAZARD AREAS ', �jg1'V4 _ _ ' -._ �'E��'r}��y. WE13TxIST _ i. � ' �tl �-��`�1�5.:-- .�._ . , '+.ti _ � - w . ', _�� i ' -' - 'i l�' �—�y.:-~.:L- �_ .�� '� ' �i -, � "'�, • �r W � . r Cl .''�_�-_ �..., � � l� w �! � ��p�. f�� ` "� � � R � h ' i � � � ��: �' I'. .,. �i: ��'.,- I �� M �t N=17fh P!, � r�fr�-: ,,��5'�'` . I� � ----• - �j , i � f7F 13T115T i �z •, �,� ��ntf sT�� - s` - f��,�� f�e nta n 'ti� ; . i; ' , : _ .t i� � � �i . � � �'S�., � � �112TH AfL. � . . ' �j SITE �`� � �,i�rsT I a � 5 � �I. � frEilTFtCT .ti4 r �i � 1 �f �; ��. '� w . � �StirHST � �i � , � i y i i ��,. �� _ �� .. , ... . � . . ' .� ; �- _ _ . .. . i� ,v H610Tt1� � - . (CJ 2608 King Cwmiy p 540ft �r-^.-•r-1 � Highli9hted�eatura - ;` p,l�- ;_� Couiity Bnurtdary Lo{.-. I� y� iNnuntain Yeaks Par; Highway5 � Lakas a Stie�ts �,f Stre�ms llgh•e�z�. � SAfl Landslid� (cont} 02012 D. R.STRONG Consulting Engineers Inc. Page 9 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton FIGURE 8 KING COUNTY IMAP SEISMIC HAZARD AREAS I I ___ ---_ IJF�}�� !fE 15TS1 ST ,� • ;I j �t��Ti��S�"�'V4 - 1 �ti � �i _- . � . . � . � ' . l71' . . ;'t� . - . � � �,�� .. _i.:. z , \ �1 �-�'`,� 5 __ ��,` __ _�: � �, �� , �:� � �' � ' � .�_ —�`� � ; `�ii �y, fi: i ' ,,. . � �yL?S'` �i -- "'-�. �i � � p� � if "�'� �. � � �� c,3 �. iq�•'-� R �+�, �� tu��r►r� � ��!� ��;�'�'� h�, � �1 ' � � . � r � _�- . � N6�19Tti ST ( ��,y`' . �k t �.. ... ', t��enton �� : N�1?TFf ST it�1�T}F ST ,� I � .' �I � t zf �t�, SE 1 tZT}f F� �� SITE Z `��`� � �+irrarsr a �� NE11TlrGT �� i . � . ' � . . . . . I�y` � � ' �'i � � ��T��u�. . .�� , , 5 �1 � . ti . _ 3 _ , . ' . . ' ��'4 r,� NS trml p� • �U�2!�;�5 K�ny-Ccunty fl ,S�7�ft �,� La[�eRd � Highiighted€eatur9 p,i�,;,i, '_� Cuunty Suundary La�a� y; hlountain Peaks garcels 3iighways � �kes and Larga Rivers Streef� ff Str�ams �' lligfiway � �p+{3$eismia -' {�COnt� L_.: I_.. i ' � F� � i_ ! 02012 D. R.STRONG Consulting Engineers Inc. Page 10 of 23 Level One Downstream Analysis Pipe�s Bluff Preiiminary Plat City of Renton FIGURE 9 FEMA - FLOOD INSURANCE RATE MAP � , ; t_, ', ;- , ; _i �� ,�� i , , 02012 D.R.STRONG Consulting Engineers Inc_ Page 11 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton FIGURE '10 KING COUNTY IMAP DRAINAGE COMPLAINTS ` ti: -,_ . ;,r " - ' . . . - E H;'ri-r s�r i�sn�sr �N��j�[=3-a�'*li7 : :�� Sr ��5. �� ___ �.;_ : , �� '�� "� -��j?+ � _�.� -�_-, . " � �'ti �. ;� = r� �� _ , ` � a' ;�a"`�p -i x . } 4. . � . . - . 3r� , , _ �}- . ,`-5 . d .. .. 'i ' �}',1�. , � �5��; ! �' i i •s:{ _ti ` � ��a i � �1 ' . N813T►f Pl._ � •� S�t;�"�. '��,,�,�ttit�". : :�� .` - _ � I� ,, 's ��` _�i6 t3Tff sT ! . i i i i 5 �' ' -- - " , ��I� �=i �j . . .. . . �_ ' . . tf�12TkISTi� • k�1 R'Q.n�Qn .. � . !I �� ZiH ST r�id� i . , � � . � ` 3 . . � . . . � .. _. ul� �'1, SEti2T}4% , �� . •ti 5 �� '� � �n�fsr 2� _ �. � . � �; � NE 11Tlr CT $ I �; � ,� � � l �.�:, : � wz � r�s i irti sr ' :,�� . -. ; ''I � . . . �'S5'y� . :I� .,p N�1(1Tt#PL � �C)2D99HingCouniy 9 __ ___ 5fl9ft ��C�f!Rd � �alo�tod Pnr�cie� ' ti�hW,r I_� County Boundary an�. � Mountalrt PeakS �'9'� Hlphw�ys Pareole ♦f lncorpnr�ted Area � �ko��n�!L,�rfl�f1l�art� fr 5treets flJ Streams ��ontf � '� Lt�a�nnpe Complalnis 02012 D.R.STRONG Consulting Engineers Inc. Page 12 of 23 Level One Downstream Analysis PipePs Biuff Preliminary Plat City of Renton £� l aBed �Carung�iag a�•,i�.esc+�',+s��e��gF� �r��.�w� L LO�l�dB lC�nS I.roS�''-1'�"� �1�1 �� N o o � e�e c� nnti es c �� , 7��' ?i� �O e° [; ar os e a �� =+aar+ m P! a� :�J:4,41 R..��?i Ts}�'u�F�W�A dC't=L 71c3�7qy � �SV"_ '�1"' , - -_ _ � - _ __ ___ aF�i ��.7t•'::'3. G'=._-- _y�__ . . . __ _ ' �'.sr L_ :9AE T � ,.�..,R. ,_,_ ,,,,,,�,.,.,,,,,,.�, ,� m 1 � .. ,+,�+* l�� w�•`w. ., r �L' ;n� � _ �3'JE,ib . �t, a� " t:�, iy �'• i�I I�Y �,'r'�[ r +, �#+� �r�.��- �"r, y �I� �� :ll� e Q� �` "zt .� `�i '�� +�' , I a �� ,y�� 7 � ,� � €. � . � �� .'M'�"' N ��.r��`„� � �� r y,a�t�, � i';'k' .�;;, I ... . . ., .. � .. ` � r:.` :,�.�5:�� ?;,"'I,,,�.-,[` . �;''" � . :Sk' . / � � � '� �,aNi+'n:�+�~ � ,W %` 3" .�_ F'}1 (� �s ' `� ��, -� ' �,��xi � ` d�^ ' > ��`x,�t�.^�� +�, �� t,� � �'� u+� �� _:,��''� �s�'�"'�' „� , ��, IM'� ,i �,� � - ,,,; ' �� :b. ,n,�. . � :d a � - "�' t4 ' � 4{ 1 A'4' ' � � �%' '�`�ryw . ry �g, .. � �'�� i � � — �+y.�^ 'r{Y'�,+��''. 4�F. { ' j .r..�, . �.� V. ,,,y� .. (0 Y` h! . �, ^,I C ,- �� "�C x< ,. � . � 5 �x�l r � �Fa��l4`��k��`�'�K.��, � � E _ � a ' .. r J >.� , � ; -a � �r " '� y�., � .a� T O ,.-�,a�� .r ^�n h ' C�y�.Fd�yy'�',y"��, r-�`• '��'��`4 .�� "� �k. a W � 'r_S�W'�'�„ �u� `5 �X i �u,�, 1�k��[R�^ na�.r,it, . � F 7 � .:i�+ �� + ' !�. _ m ii � : , k �� . Y � � �. � � � ��. ' � ' /� �! H"k�� 't Q V ' Z .,a,y, {,a� ��; � � '�`�� '�� y ��` . fRt4t�` a � � :'jr � ��T��. � � °u� � �PC M1�� Y��t + � , U �t� ,t�"• h�'� �� . �4 �"t�` t`� ..�� x�� ,�� rt�- � ✓ r .`f� '"y" �h a r��.b� �.� ty .� �, � Y U � �t .w�".:� J. �'��.. :'k Lk. �F �� 'S� �'". � 4y �. . C Z _ ,�` '� { '. .�; 'x� ��a�,.lr "r �"' twr''�'+ w � " y � � t�t., n t� ' � ' r� 's ti`� i n �i *k q`-`,�k �} � ,.1';�- ,'y�"7 �w�.7A . U7 �;�:� mf,� �^ x`� �r� � F .�1`� � � «;-�,f �. '� r�t�n�..Ft N�,,. N �H. 4 ° sS.r�j� t�I a'. .`_ � _ � � i W ' + ' ,d,,, � � �,q M' .. "CK3.� p�c �,YT,�`�k�. ,.�n.,....._,r� . A C N • lF,a4F '"� e` — .__ -. .._ " . . -�_.n�. . . fn u. * 7_ ? eE�' �`-'' " L � N ., . � � � � � _ `��+E� ny '°.�p y'y �� :� � ,h- n r , ;� n � T �;�� 4 ��a� � ,�ce'' a;{� �l�y.` �,�Aw'Se: �.�'ry�a+'Gr�v ;� �Q �'"�, � �h�� ; ,ri4�:r`. ,,�*„m � �.y.. �r � Y . ,. , ., - , _ . , . _ �^ ' _.�.. w . " ' � Z m _ < . — , .::; .. ..��, ,.�.r.< � 'I W O .u.ae�7 .. � � i H .u,rr-_.L � c �.1:5 OCIC�S if?. C5:'� T��_; _�C r �'?�'J� S_yy f.3c��'' 7:_== G_oF.:: � � O r� �� '• - �� N �u�8w��e�L1'e'd,d Atun�L�r3:y—dePJ IloS O.�i � �_�_— ___� —,— . .__ ---,, -- - ' --" �_ __� �- - i AgC—Alderwood gravelly sandy loam, 6 to 15 percent slopes Map Unit Setting • Elevation: 50 to 800 feet o Mean annual precipitation: 25 to 60 inches • Mean annual air temperature: 48 to 52 degrees F • Frost-free period: 180 to 220 days Map Unit Composition • Alderwood and similar soils: 95 percent • Minor components: 5 percent Description of Alderwood Setting • Landform: Moraines, till plains • Parent material: Basal till with some volcanic ash • Properties and qualities • Slope: 6 to 15 percent • Depth to restrictive feature: 24 to 40 inches to dense material • Drainage class: Moderately well drained • Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately low (0.00 to 0.06 in/hr) • Depth to water table: About 18 to 37 inches • Frequency of flooding: None • Frequency of ponding: None • Available water capacity: Very low (about 2.5 inches) Interpretive groups • Land capability (nonirrigated): 4s Typical profile • 0 to 12 inches: Gravelly sandy loam • 12 to 27 inches: Very gravelly sandy loam • 27 to 60 inches: Very gravefly sandy loam Minor Components Norma • Percent of map unit: 1 percent • Landform: Depressions Bellingham • Percent of map unit: 1 percent • Landform: Depressions Seattle :�2012 D. R. STRONG Consulting Engineers Inc. Page 14 of 23 Level One Dotivnstream Analysis Piper's Bluff Preliminary Plat City of Renton • Percent of map unit: 1 percent • Landform: Depressions Tukwila • Percent of map unit: 1 percent • Landform: Depressions Shalcar • Percent of map unit: 1 percent • Landform: Depressions AgD—Alderwood gravelly sandy loam, 15 to 30 percent slopes Map Unit Setting • Elevation: 50 to 800 feet • Mean annual precipitation: 25 to 60 inches • Mean annual air temperature: 48 to 52 degrees F • Frost-free period: 180 to 220 days Map Unit Composition • Alderwood and similar soils: 100 percent Description of Alderwood Setting • Landform: Moraines, till plains • Parent material: Basal till with some volcanic ash Properties and qualities • Slope: 15 to 30 percent • Depth to restrictive feature: 24 to 40 inches to dense material • Drainage class: Moderately well drained • Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately low (0.00 to 0.06 in/hr) • Depth to water table: About 18 to 37 inches • Frequency of flooding: None • Frequency of ponding: None • Available water capacity: Low (about 3.6 inches) Interpretive groups • Land capability (nonirrigated): 4e Typical profile • 0 to 12 inches: Gravelly sandy loam • 12 to 40 inches: Very gravelly sandy loam • 40 to 60 inches: Very gravelly sandy loam 02012 D. R.STRONG Consulting Engineers Inc. Page 15 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton TASK 3 FIELD INSPECTION UPSTREAM TRIBUTARY AREA The upstream basin area was evaluated by examining the King County topographic map (see Figure 1} and by conducting field reconnaissance. The Site is situated near the top of ahillsidewhich slopes from the southwest to the northeast. Runoff from Hoquiam Avenue is intercepted by a ditch/ culvert system prior to entering the Site. Runoff from the parcel to the south of the Site is collected and conveyed to a private drainage system (currently under construction). Since there is no offsite area contributing runoff to the Site, there is no upstream tributary area. GENERAL ONSITE AND OFFSITE DRAINAGE DESCRIPTION The entire Site slopes at the northeast at2 to 15 percent toward a single Natural Discharge Pointat the northeast corner of the lot and is intercepted by an onsite Category 2 Wetland and a Class 4 stream. From here the st�eam conveys runoff northerly to an offsite Category 2 Wetland. This wetland extends north and flows through a culvert under Hoquiam Ave NE and encompasses the remainder of the quarter mile downstream path. Runoff from the developed Site will becollected and conveyed by a typical catchbasin/ pipe network to a detention vault in the northeast corner of the Site. The vault will discharge to the onsite stream. C�2012 D. R. STRONG Consulting Engineers Inc. Page 16 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton TASK 4 DRAINAGE SYSTEIVI DESCRIPTION AND PROBLEM DESCRIPTIONS DRAINAGE SYSTEM DESCRIPTION � The downstream analysis is further illustrated and detailed in the Downstream Map and I Downstream Table located in Appendix A. The downstream area is located within the , Cedar River/ Lake Washingtonwatershed; more specifically the Honey Creek sub basin ' of the May Creekdrainage basin. The downstream area was evaluated by reviewing available resources, and by conducting a field reconnaissance on May 16, 2012 unde� overcast conditions. Downstream Path Point "A" is the NDA for the entire Site, which is a Class 4Streamlocated at the northeast corner of the Site (0'). From Point "A" to Point "B" runoff is conveyed northerlyoff of the Site as channel flow through the stream. The stream channel is well defined in places and poorly defined in others. The channel varies in size ±1'-10' wide, 0.5'-1.0' deep, with a slope of ±2-8%. Steady flow was observed(0' - ±260'). At Point "B" runoff enters an offsite wetland. The wetland area quickly becomes over 3' deep with no obvious flow path. Steady flow was observed entering the wetland (±260'); From Point "B" to Point "C" runoff travels northwesterly through the wetland area(±260' — ±1,034'). Point "C" is a 30-inch diameter concrete culvert which diverts runoff under Hoquiam Ave NE. The inlet was approximately 3/ full of water and debris. Very slow flow was observed entering the culvert (±1,034' from the Site); From Point "C" to Point "D" runoff travels westerly as pipe flow through a 30-inch diameter concrete culvertunder Hoquiam Ave NE with a slope of 1-3%(±1,034' - ±1,064'). Point "D" is the outfall of the 30-inch diameter concrete culvert on the west side of Hoquiam Ave NE. The outfall was approximately 3/ full of water and debris.Very slow flow was observed exiting the culvert (±1,064' from the Site). Point "D" to End; the remainder of the quarter mile downstream path is within a wetland area. The analysis was terminated at this point. ��2012 D. R.STRONG Consulting Engineers Inc. Page 17 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton FIGURE 12 DOWNSTREAM MAP 02012 D. R.STRONG Consulting Engineers Inc. Page 18 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton � I ' W 2 �, I � - _ I W o ° I I - � � � 3 N O F2`� j ° n I � ti y � a 2 w Y � � U g � o a s � a s f� W � N F � ,Q i 2 0 c� CREEK 2�02 � W o --- `'SS � 2 � I �Q � / � G9ti Q I �� I � � � w -� � � I I \ „�,. I \ I \ \ � \ \ � J � � � �• \ . NE 13TN ST � WETLANDS � Q' I \ ` ¢ � � � � I � � � I , W WZ � \ 5 � � � I Z ` � B" � � � I\I O RT H j o � J � � GRAPHIC SCALE m 0�1+00 200 400 � . NE 12TN ST � `� . ` 1 INCH = 200 FT. � — — .ao:_ ' � =— v _ i � ' � ' � .'��,��"; Y ��. � �==— �� 1 .� _V�� ,�\��_�`�.��\�?�'N- — � =` �._� � \ � ��" C�T � �t,� � � e ��* ��- -- '=_� � �'�L � \ ��.v�y`l'�� \ �� \ ?z8:; �� : O' 1� � �,Q� �.� ' �� r.=:- � Q � � � � �•� � �y�.� L �3'„�:��__ i ��_. ��bt"sJ.�.�_X\�`ti"1 b�S�'. I p �� •_-*� =� -� a _ __ 51��`d"��`C��-11 1 �� \�.i .�� tl �.� � �_ _�F'T � ��1Y� /�� ;��y g_ ^ -- � � \ . __ ' a ` � � . `.. \ .. �-�� ti � �T�:��0- � �� Q`� �l�,� tb,�,... _:� � � = �a— G, '—p'� ,a-��i�.�, ��. ., � .._o:� � , �� _ . �t. . �`�` .�.�� `` --- � � ,. �� , .`� •�, � � „ :� a- ��:�}--L� �� r='��=� ` ``�; ,.___ R, . .� :� z \ \ . . ,..v.�, e,..�n / r `, \ � _��`/-.:' DRAFTED BY.• pR � � '� DESIGNED BY• NAK z� PRO,�FCT ENG1N£ER: LRJ � DA7E.• Oa�2p12 � PRO.ECT NO.: 12029 �. R:\2G12\0\12029\3\Drawings\Plots\PP\Report Figures\61-3DS�IG12.dwg 7/37/2072 9:35:23 AM PDT F7GURE 12 �� COPYRIGHT OO za�z. D.R. STRO.VG CONSULTING ENGNEERS IVC. FIGURE 13 DOWNSTREAM TABLE BASIN:Ma Creek Symbol Drainage Drainage Component Slope Distance Existing Potential Observations of field Component Description From site Problems Problems inspector Type, Name, Discharge resource reviewer, or and Size resident Type:sheet flow, Constrictions,under capacity,ponding, tributary area, likelihood of problem, See map swale drainage basin,vegetation,cover, % 1/4 mi=1,320 ft overtopping,flooding, habitat or organism overflow pathways, potential impacts. Stream,channel, depth,type of sensitive area,volume destruction,scouring,bank sloughing, pipe, sedimentation,incision,other erosion Pond;Size:diameter, surface area A DISCHARGE TO ONSITE WETLAND O CREEK FLOWS THROUGH THE SITE AND STREAM A-B CHANNEL FLOW t1�-1 O�WIDE, 0.5�-1.0�DEEP 2-8 STEADY FLOW OBSERVED. CHANNEL IS WELL DEFINED IN SOME AREAS, POORLY DEFINED IN OTHER AREAS B STREAM ENTERS WETLAND ±260' B-C WETLAND 1-4 � MUCH OF WETLAND IS OVER 3' DEEP C CULVERT INLET ±1,034� SEDIMENTATION VERY SLOW FLOW WAS IN CULVERT OBSERVED, INLET±3/a FULL OF WATER AND DEBRIS,±6�TO FROM CROWN OF PIPE TO HOQUTAM AvE N E C-D PIPE FLOW 30"QJ CONC. 1-3 D CULVERT OUTFALL ±1,064� VERY SLOW FLOW WAS OBSERVED. WETLAND CONTINUES WEST FOR OVER 300' 02012 D. R.STRONG Consulting Engineers Inc. Page 19 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS A review of the King County Water and Land Resources Division — Drainage Services Section Documented Drainage Complaints within one mile of the downstream flow paths revealed no complaints within the last ten years. The project should not create any problems as specified in Section 1.2.2.1 of the Manual and therefore is not required to provide Drainage Problem Impact Mitigation subject to the requirements of Section 1.2.2.2. Project runoff will be collected and released per the Manual's requirements to accommodate Level 2 Conservation Flow Control and Basic Water Quality requirements. During construction, standard sediment and erosion control methods will be utilized. This will include the use of a stabilized construction entrance, perimeter silt fencing, and other necessary measures to minimize soil erosion during construction. R:12 0 1 21011 2 0 2 9131DocumentslReportslPreliminarylLevel 1 AnalysislLevel 1 DS 12029.wbk 02012 D.R.STRONG Consulting Engineers Inc. Page 20 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton I� � APPENDIX A PHOTOS �r �� :.. , ��; � - : , � - x� , _� �I �f r ?, � � :'� � 3 �� .� F � �� ' ,.�Ti , / ��..�� , ��y,� �4, �;�� 7�..: l�t�� _f.��- raL..: , .n�.^.. _ .��,� h d ..f> ; �� .��-,".� `. � • �.�r tG � r rf� }J � �iZ�} `-j'�`•;'�i _� { .. �� .�, y „!.�G [ � . .: � .'C }� K� J;�� ' w �. - - �� _�.J \ - � 1 i . :� r �� f��►�` -e�c .,�S��.r;, ; - ! J � t';-ar��L1 , ��7' . . . N�'` � .': `�'� a sti'h` / `'��y � r " .,�" � ��` a � k�, y�, r'� T,j s"r .y - - t�s", x;' ,�,a ,�� a.,h f 't r � L .�a, �.��. � �'�F�'S��'.-:'` �' "l �F�o�i ' � h�u�rgi 7 � '.�! �� w �.. �� $ '.,, �+'1 t,�:: ��_ �i��,,,1�` a't S�^ ,S.a.t�� c,•. t a- --+ .. � � "ya ��i i� "Rt i P t ��.� =�r �_` ��'.,�� T ��'��"'``��i e �rr�,- '+�g`t��;yx: R� �+t ��.3 � �� .�`��,4`G �,�.�.°y�'f� �� *'�y t � � y�, �{`" � �F6�" "� J �� b b • � .'� { �'dM�Yk A'�}s y. .F.� � �a. �` . �� .�,�� ,.i � �i. -�-ti r.�;'. p4 _ � _ �� . � r t c�.y � �� ,a � � :.�C..�j �� .} `.� �• ^,'�..'� �' , � � � � - �„ '.-F+'. — �'y-' =^ � .�!i'� �r, ' ;'... , T�.-� =� - �f_ z;` _�' a •� �a � ..T;_ �•.. 4;.� `' r �i .. _ r �M1 � . _ �� :3.��:. �' � ' �` � * ,�.. rX��''�,:+1'� � ��..-� , `�•:t' r . "' xq � �:;�¢ � Well defined creek channel between points "A" and "B" 02012 D. R.STRONG Consulting Engineers Inc. Page 21 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton ;�. .�� - �.��,s i ..- - ' a , �� ,�,+��i„�'�'�fl��- .� `.{"`. _ ��i'' t j� ��j°� , � .�u`�,�,..�+.+5'�fi�ir�';.� ��p�,�� i �-'� q�a ,� S. ��' �._„c�.��x 4,�d,��%^�ay��t r''�4�� i� �' ��t� ' �t, ,� r' �,�_3`�'�..,1�Y.�!f t�.,.� ��1 r��"y �.��:��-��r a��'rs.��` 't"'" - ��.�y,��` _ . f z�-a � � r �'��'s?- '�� . ! ��,c��:r�y'` •�_ �2��- -�,t��`'ry, w�i,`r�, � �� . a3�+;i. -� - ° �` �r z�� '��,,j i�f «�i�'�� { v � �. � ` r — ,�y� t �`�� .qYA f - �` i�"�� 3s�S�i�'� �<, � 1�A�`�,��' . � � �Y nY i't �t y�S,l �(1�T��I p}5�1�' �\� _ �r � ,�, ' ��'r �� . ��':�' ��a��i�,�,'G''�'� ' .i � �' ' � ,-,� � � ��'`��i� f� r �b ;� '�r �'' t� "� .,�a..�,'��`�$�, .��'�� ':-�' `"';�` `-4��:=v' k._ � Y��,�� C;�t,1a �+ t r`� s�s�,1��,�� :�r ,� r� 52 � � �� _ � Q s , r �� L ' , r�' b � ��►- � �. -��,� ! �g, ��. ��,,, � � , �!�. � , ��.r - ,� � ,��(� i a E 5 ]7 J�i • =� � ,� t' -,�"-2'-� ��. � �e}� S' �yJ�� `_ .��s .s.. �. �3. �� t�.� �,t �_1��;' ��- ,'r. � _ i _ � � �r�� '� E r=�i �A �b. %, 1� � __ 'j � "�'^lr,��' �y�, d �4r' '1,'+� � ib � ,�.i.l;� z �.. , , ,;�� ^��,� " I � z a � �� ,�, � ' � �.-; �'� � 'c.�,-` 1 s � /�'�. �' �'°- �T" '�a ,t �-.�� ,�r.. �.�. -,� - - ; ~�.. � � •:� � , � .�. -�� `t�}� '�i , .,�, � �+'"A � t � _. ' ,� i ` r __ •'^i ji. - ;,. � �� -T'. - -� - ��_.� I�� : _ ��, =� ,��..� _ ��-.. ��. .�. �� f�. . l�.. �� .�. '"� .'�7� �-.7�L�i�;��X�'�`` �_4 � ��`�v,\� A � � ' �!!'�. . .... . � ��1'.��73?J1.'•�_"��:i " � � `...� �,~. .....�.,_ �' ,.._l:.:� _ 4 . . •�4 �. � . Poorly defined creek channel between points "A" and "B" 02012 D. R.STRONG Consulting Engineers Inc. Page 22 of 23 Level One Downstream Analysis Pipers Bluff Preliminary Plat City of Renton i �� . ti � :� �_ ,�- �� :. s , �. � 9 �.� � � a �+� � �. � s''��''� '� k �;� � 44'�#` `�` =; ,�g � � ,,. �� ,, - ` � �`�' ,�` �r - � �x '� sx�,i �q c� � �"'.� �„r` '�';r�a s: _f, �� r, b. 9��:�.•_ •. t_ ��'� � � 5��..k r f' �� '� 7,� _ � .:1 „e�; �� r r ,, � � � ��-.��' ' ' �►f_� �� " `i`.-` i� � —'7'� � �t . J� �• .�= <�4, S��s�,��•� .�_ 3 1,�z',- �' i�>r ��i � i ,` �� .�� . �•b ��' .�jr..IN.`r;'r .-7'��•��,. �r � r-.4�,fyr' .r , - "�»� A .l�� `'��Y. r .� �� .w(�l' `� C� .F a� 1 t" �,,. �l,�,� ^� � �'�.^~r,��i� l� -. f{ � � �J `��'� �� . .. J � �5. �F '.yl� ^ �� ' �' , � .s�'3�,�� . '� y.�� . ��_ � ,��'�r'4�>�� Y� 4:.�_ 3 _3--�� " 7�+ ��, ^'`� �-�,, �" , ! � �I�' �Q��a�.�'. �f.� '`��.'—�� ,�a • '� �'�,',� �,.:�,q �� '�'� + r , z.ti �.°"�:�'d` /'� �4 "�j,' �S: � r ,� � � �,.� ' � �'; s ��-_ �'' �.` ,� �7��, }.�g ry lL y(� �� ` Y ;'! -t'lr��"_ Il��'j r:;�t" i � �1 _ 'd ,��'r•��. T l� .3': _ � I.r 'yi �ls� 'T. � � ::5�� >^ � � '• � r ^.��.:,'.' '!' i ��_•��S �T l> �¢``.' r �r�,1.4�.� �� 4W�i�i � f� r� �� * . ,a,� � ��f�� r _ i ��,; .,� °r� .� _ s o� � ; �'�{ \ `a�, �s, '.�,�`. :� _ r h ��- � � ` __� . � �� Culvert inlet at point "C". I Ij �2012 D. R.STRONG Consulting Engineers Inc. Page 23 of 23 Level One Downstream Analysis Piper's Bluff Preliminary Plat City of Renton � i I ,_ SECTION IV �� FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN I EXISTING SITE HYDROLOGY (PART A) KCRTS was used to model the peak runoff from the Site. Per Table 3.2.2.b of the Manual the soil type is modeled as "Till" for the Alderwood gravelly sandy loam SCS classification as shown in Figure 4. Soils. The entire Site is modeled as "Forest." Results of the KCRTS analysis are included in this section. Area Breakdown Predeveloped Area I Till Forest 216966.00 4.981 Impervious 0.00 0.000 i � I �I I� - � I �J2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 14 of 43 Drainage Report City of Renton PRE-DEVELOPED HOURLY TIME STEP MODELING INPUT: - - � Land Use Summary �,�� .�� "�`--� :� � .,. _ � F_,: - � a i . Area ? Till Forest� 4•9S acres Till Pasture 0.00 acres ', Till Grass O.QO acres � Ouiwash Forest O.OU acres Ouiwash Pasture 0.00 acres Outwash Grass 0.00 acres Wetland O.OU acres - Impervious 0.�� acres Total 4.98 acres � Scale Factor : 1.OU Hourly Reduced Time Series: predev » Compute Time Series � Modify User Input I � File for computed Time Series [.TSF] :� � PRE-DEVELOPED HOURLY TIME STEP MODELING OUTPUT: Flow Frequency Analysis Time Series File:predev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.314 2 2/09/O1 18:00 0.402 1 100.00 0. 990 0. 085 7 1/06/02 3:00 0.314 2 25. 00 0. 960 0.233 4 2/28/03 3: 00 0.241 3 10. 00 0. 900 0. 008 8 3/24/04 20: 00 0.233 4 5. 00 0.800 0. 139 6 1/05/05 8:00 0.204 5 3.00 0. 667 0. 241 3 1/18/06 21:00 0. 139 6 2.00 0.500 0.204 5 11/24/06 4:00 0. 085 7 1.30 0.231 0 . 402 1 1/09/08 9:00 0. 008 8 1. 10 0 .091 Ccm.puted Peaks 0. 372 50. 00 0 . 980 :,2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 15 of 43 Drainage Report City of Renton FIGURE 5 PREDEVELOPMENT AREA MAP � � _ � ' I ; , i �� ._ . � � . i 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 16 of 43 Drainage Report City of Renton - i � ' -•, � . .. W _ , - �.,- ... � i � - i � ' - -- -__._._ , r ` 1 - - �., __. t � .. ---- � � � - ,_: .;____ .._: , � < t '+.' V' m � -,. . _. �,. , .<r -- _._,_�. -.� � , , , _ . _... � , ._ _ , ,_�. , i _ �.,,, - , � . i�"' 3 � ___ , , - _ ._ - i �.cc � . � . � � .. . � � . - - _,_ ; .- ,, : ... ��..r �-- � _., - - . . . ' . . . . ` � O n'�! . e_, W _ ' - , ' _ � ,,, . ��- _ � __ , y _...__ . . .. . _..,__. . '_ �, �'' • y ,.� . .. .� .�_ __, _ -,,. __�.. , -�-.. � . � 2 �,< , . . _. - __... . Y � � � � _ _ __ . _ � -` _ - - , , ; . _ � _ i', �_� . � �: _ _ � Z 4 „_--- � — r, ` '" - _ r: �•. �,� _. � < - . `_ .. _ _ 1 O U -. ; _-- =�__ , t � _ _ . _ - . . � -;, ,. _ _ � .. � -.:. : ; _ - � _ _ - , . _ .... ,. , --- - _ ; , _ . _ . , , , _ � ; - , . , _;z.,, . ,. . -. - .- ,:- . , - - _ �- . .,. ( ,- __ ,., .J'j` . I � �'. � � . � ` _ _ _ - /T n W - _ l _ r i F � � t ` � ';— �,�` ' U 11 ' ;� �r � � _._-__ , _ _ _ _ � . _ _ , , � ..::.�- _�.�E�,�,<:�__- ,. _ _ , .. _ _ � . . �. . - .,• --� \ � ,.-r . _. . _ 0 2 � , y — �� , ,:� -. y� . ..-:, .,.. .. -_:.. . : , �, - � �- W . � � �� -_. ' ' _ ` • . �. �. ,'� ' _ . __ , . , . �.�� . .. \ ,. .. . ..,�, , .,";�:. .-� . ..,c ._ - . �' �: _;. 2 d : .�• 4 ,.;.:.-.'�. . " �.' . '.--- -- - - - . £ ,€.. . �� _ .. ._. � � i i' - ' = - � - � ' _ ,. -.. ,-_: ,:�' _ ; ; '�.�-. ' , . ,. ' ` -• ' �. ' . _ �� y �� , . Fe-� J A�_.•.�_-� ' ,: '�. ' .�, -:� � .;.. .... �. � �... - . - \ . .._ -».,_s? �` �I � ;-. �.. �.-._ - _�,"_ ,-...;. .. - . � s� , n ." _ , � � .. : :, ' r. . i :. . . . . , .; __. . : � , . . �. . , ' � _ � � . , _ , . �} . % - - .. _ , �., , .., .-- -i ,� �- - ;" _ .�� _ -, , _:_ _�. . _ � . . :. ._. .,.. ._ :',� �. •. .t.. e �. J _ _ - W _ F y . . _ _ . , , , , . ,; ; -_ ___ 2 � " : - � . .. _ � � � �. � , . . � , -� � . � � �� , °� a�i ' , A '� . � ,�.:,, . . .. _ _ . .. :_: �;.�-.,,, , . - ._. ..— . � - . . � __- __ __ , . ...� . �. ,.. �;�`,_ .� � . � .... . - —<: _. .;c� . ,.., , ''.. . ." _:'' _ . ...,� �' , .� � .r � .. .._,_;-.:�: , ; s �, .,;,. �_-.� -. .-. >� -_ , , � _ _ : , _ . ._ , ' . � . . -.:. ..�.:A�::�� Z , .. - , { � -, , ..-, . , ' _ \-. , W : _ _ , ., , , ., < �.;+!G E� ...5`_'. �. , �.. -. � .. . . ... , .:: ' � . -. \ 4 ♦ '. � � � . ,.� �. ; '� _. '�. '_' . ,. : - . .. .; . ': . .�;.. �' — •t _ <5' q_ . ._!�. �� . . , - — _.. _ . � ` . . . — , • '� _ .. . 3 , . . _ '; _ . .._. �� __ . ' _ �. -� . � . , �� ... � '� _ ,, .. . �. �, . . ,.� r _ u _ e<i.s: l�':' . _ , �.. � ^ a - � , :c.'t' ..:;..._ : .y . '._ -, . :::: . _ .�. ` : : ,. � �„ : �. . �} _ . ! . � '� .M1 ,y �` .. ' t . -� :. `, - ` c, � _� � .. 9, .- � i -� ,, '�.v. � ' ." _ ' • , .. . , _- i : • . _ ,. . . ;' � . ' , . . . ' ,. .. ... .'. ,_ ; %--: . L .y , ., . -. . . -- ,. . .. . ._... � ' /y . -._ -. . �.- �. ..�. �,,. , . _ � . _ . .. -:,;� .v� � �� "� _ , . _ ' - _ " - - . : .-.�.. �, ... _ , - � „ . _' . . ... -.. . ' O� �� ._><_ " ; _ ;:- ' . ."�._-'�� -�� .� -� . .� � .. � . , � _ — — I . -. ..R_ __� - _ _ ' I - —. ___ ',' . .... - _. � .,. .,_ ... , _.��.� .... ,' _ ; �I .. . .._. � ,.: ' . I ', �. . " _ ' _ _ _ __ ` t ., __ +. .c,: . . . � _ _ - : �' . - ..._ . " '- � ... � . ..�. . ` . .- ` ". .. , '-. �-. �:., ,� ` .... . . �' . : .. .. . ',. . T _...- 1 � � � WO , _ _ , ��. ��_` - -. _ - �;: -� . � , __.,, � > _ ,. . , , , � �� .:: _ � ow : _ _ . - � - � � , ., � ; _,; _ . . -. , , _ ; , , , � �. , ._:, . : . .__ . . ! ;; _ _ .: . �' - ' \ , �" �� %.'.':. !.: ._.. '� _. .,:. '. . �.- _' .. c:1.A' '. �' Y ..: /.... �.. . �-` �'' � � - i . �,� � : _ �`: . � ; � � Q � . ,. : z .�-_� . _ _. ; � ir� � . .,, - ' ,` _ :: - - , � 4�I c� a O . �:. � : � ; : - � ; ,- � � , , . . , . _ � , - �-,.. ., ��; , _. � �� .�� < , .. . _„ . ;� �� - . _, � _ _ :- �: . � , _ ; , ,' ^, ,. � � a � , v� - ;_ ; , ,. . �,- , _- , k ;� �u �_ . ,, �. � � =- -- � — ; � W , ,. , - ___ - � � ; , : ` _ _ . �, , ..• . j �_ _ .-_ � ; , , , � I `-- I ` _� �i ; , . _ , . -:. �y . ( '' �" ._: :". ,/.:, /.,�:: .. a . ' .:: . _�., " .�.. '. - I ..-- I � . . ..... �. .... ;:: - �._ ..,. ,- I - .. AREA BREAKDOWN , � TOTAL EXISTING SlTE AREA: 217,369 S.F. (4.990 ACRES) L E G E N D TOTAL PROJECT DEVELOPMENT AREA: 216966 S.F. (4.981 AC SITE BOUNDARY N � RT H � � � � � BASIN BOUNDARY � (lNCL UDES 10,337 S.F.OF SI TE MOD£LED A S TlLL FOREST DRAFTED BY.� NAK FRONTAGE IMPROVEMENTS GRAPHIC SCALE G£S/GNED BY.� NAK ON HOQUTAM A1/E NE AND EXCLUDES 0 30 60 120 PRO,tiCT ENG7NEER: LRJ 1 D,74 D S.F. OF NGPA AREA) `�i� cA re ot.zasota PkD,IfCT h'O.: 12p29 1 I NCH =60 FT. �4:\2C12\C\12029\3\G-cvFngs\Plots\Engioeerirg\Repo-: F'g..�re=_\01-3FIG512029.dwg 4/26/2013 4:�1:27 PM PD? FlGURE.' .5 COFYRGHT Q 20'3, D.R. S?ROKG CCKSU'�_-I�� E�dGYEERS INC. DEVELOPED SITE HYDROLOGY (PART B) DEVELOPED SITE AREA HYDROLOGY KCRTS was used to model the developed peak runoff from the Site. The soil types are unchanged from the pre-developed conditions. The portions of the Site within the proposed clearing limits tributary to the proposed detention pond were modeled as "Till Grass" and Impervious as appropriate. Results of the KCRTS analysis are included in this section. Area Breakdown Developed Area Lot Area 132509 3.04 Impervious 86988 2.00 Pervious 45521 1.05 � ROW, Tract"A","C" &"D" 84457 1.94 Impervious 51061 1.17 Pervious 33396 0.77 Totals Impervious 138049 3.17 Pervious 78917 1.81 (Till Grass) G2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 17 of 43 Drainage Report City of Renton DEVELOPED HOURLY TIME STEP MODELING INPUT: -- - - - . . , " �.i4 r`','�`�f,g`�z`�y�g4�'.s�'.� .. :� Land Use Summary � �� ,� �-, � � �"' - .r_ � , .. . � _ �_ �_�.,�,.. ...��....:� ,.:; �Area — ? ° Till Forest 0.00 acres ;' Till Pasture 0.00 acres Till Grass 1•S1 acres Outwash Forest 0.00 acres Ouiwash Pasture 0.00 acres Qutwrash Grass 0.00 acres Wetland 0.00 acres Imperwious 3.17 acres Total 4.98 acres - � Scale Fac#or : 1.UU Haurly Reduced 3 � Time Series: DEV » _ � Compute Time Series LL i Modiiy User Input I File for computed Time Series [.TSFJ DEVELOPED HOURLY TIME STEP MODELING OUTPUT: Flow Frequency Analysis Time Series File:dev.tsf Project Location: Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0. 928 6 2/09/O1 2: 00 1.88 1 100.00 0. 9°0 ; 0.757 8 1/05/02 16:00 1. 19 2 25.00 0. 960 1.12 3 2/27/03 7:00 1 . 12 3 10.00 0. 900 ' 0.820 7 8/26/04 2:00 0. 987 4 5.00 0. 800 ' 0. 987 4 10/28/04 16:00 0. 985 5 3.00 0. 667 I, 0. 985 5 1/18/06 16:00 0. 928 6 2 . 00 0.500 ', 1. 19 2 10/26/06 0:00 0. 820 7 1. 30 0.231 ' 1.88 1 1/09/08 6:00 0.757 8 1. 10 0. 091 Computed Peaks 1. 65 50.00 0 . 980 � 02013 D. R.STRONG Consultin En ineers Inc. Pi er's Bluff Plat Pa e 18 of 43 9 9 P 9 Drainage Report City of Renton I FIGURE 6 POST DEVELOPMENT AREA MAP ' �?2013 D. R. STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 19 of 43 Drainage Report City of Renton ��I'�IiV�I�I I I � . . � � _ ��:..��.:��._�--�--��-��..��..��--..-.��.r��+��-�--��..��..�:.�.��--�� ...�-��..r� _ �i�I�I�►I�I�I�I�I�I�I�I�I�I�I�I�I�I�I�i�i-i�-!•;.�:. . -. . . - - ��j��t=�=��i�i�i��j�j�j�j�j�j�j�j�j��!.iisr':��'.++��j�j�j��j�j�j�j�j�j�j�j��j'%�� _ ��►�!:�'►��i��S��SS�;►�=�=�=�.. : . .-- �� - - - �-� �.�.�..�i�� ♦ ♦ ; .. ►��I��rco��om�`.��..�-.o-��i�r��►�%�:o�aO�`pis. I � i i��,.,,j,I�y��:��,►,�- . � ��Q��i�j �i I I�i . > 's � � ! ! ♦ �► ♦ �.�i�i�i_. A��I�/�////////%///////// ////� ////��i�i_:�i_:�D_•i��S�>,O�o`!'�,i,i`` � ►►� ► . �, � . .'��i�►�"�ii�� , . 1, ��,�� ' I , I � ' ' I j�� '4��,�� j��,I� l ' � � l� / ► ��II"��'`��:`�'��1,�'hj ,�►i�i►�;I. / l/ ll l�' l � � � l�I / ��.r`4,�`��.��, � . ► �i►�I�/ /� � / / / '� / ' � � � ��1�� - � , �►►�� ► � � . � / / � � �/ � r�I I. �� , ��,I�/ , � � / � / � / • I. ��I Ii�I�O. :..< �1',,I�/ : . /� .. _ /� . . %� .: .. �/ .. .. � ...'_. /� .. . %I/� .. . /�C�,..�.��,.. ?;_ � �►��i �� / � / � / . / ►'�!�i�1i,i��.,►''�,� ^_,. (f� � '' . �► �. ►/ / �� I �1 I�I �� i . 1 ► � ./� � � � �. ►.��..�h�I.�. �r I� � � � . ►. . . ► �� ► � / � /��j� I�. .. � , , . ;��r► ,I�/ r ,/� � � ' / �//iiii �►�I►I�,�e►e��._.��'i. o � : ,��G►,,I��/ , ' �'A l ► �I►i .iiii�►�1��i�I�,�j►i �. ,��C,�` �j�/ I� I.��/,��, � � 7 ►��►4�► I\ ► ,►�,,.�i�i��► �Ii/��,�%�� % � ► � ��►��,� ��►,�� ► .'��ii��.�s�� . ��,�� ,►�> ��.� �, ,: ��,��/iiiii.iiiiii . .�o.�.�►v.i�iiiiiiiii �./� �► ,►,��. .►� 1��,I� � , . ///////.///�'."1J 3%+"4r ' ,�////.'/ / /►►�,.q��pi \ 1��,1�� ► ► ' � , �/////////////�,��/ /,�,A�,�,Ai �, �,►;•��►�r/��ri%/r�% � � / : �. /►��:,►��•,►, :�::: ` '4 �,.�,, � . � , : : ,/�i�/✓/v � ��/,_ /i. ►,. :.,►.�•,•, �'�� .. �. ��►�,I� � � � ' � � �/�j��I iii�►iI�I��I��i►� ', �,.►�,,,�5 . �� 1� �� / � % /%% r.�� ,�►,:��,.;��►� �r, � ' I �� 1 � �� 1 �� 1 � �;► , " � ` �'','�►/ � � � / �� , '��;►i��i; _r .. : ;. � , �i�►�;�►� � -. �� i �� 1� �� //' � ��►i�i'►'i��% ` � , : 1 � ��i►�'Ii/ �/ �/ /� . /� � � �/ �l l/I� /,�;IhI•y1,��► . . �►►� , , /� � � � ♦I I / I � 1 � .I�, � , �� •i� ,� ♦ �. . ►` 1 � �1 �� .� � .� ♦ . � .�.�.--////�_//// � /► y�J ,,� ♦ ♦ •► �•,,,,, _/_.��/.r��/,r��i�/r��/i� �� •.��.,.�. �� I�I��I��I�o��f�I�I�I�I�t-�`�i��i�`��►i��I��I��' � v r � ,_�/I��i��1��.��I�� 1 I ��,�•�.��j�j%I�I�I�.�I I I I I _ �.��.��I_�I_�I�I ♦ � i v ,i v. . �":.;-'-� ,- . -. I I��i�/I�� ,' ,,•,I,�,�,�� I��I�ICI�I�I��o� L�� . _I�i♦ � � �� f, III I I � � � � ♦ � � � � �►� � � . ��\►I��I��I-.�+► � , `� �1► , .�,.�i.►��i�i�i�j�j�j�I_�I_�I_�I�I.�I�I�I��i-i�� ,1��i��►�,}►��i�i�i��i�,�.!I�I�i�I�I�I�I•I •,ry� . �i�i�� ? 11�� . . .- � . . . � ♦ ♦ ♦ ♦ ♦ 'i��: ', V'; ''�� '� � �I�I I� � -� �-� �� w�I�v.a�i��rv.��i��►I,:al��♦ ♦ �.�� , � 1 I I �.��I�I��.�.�i�i�i�i��j�j��I_��I��i�.S.S ♦ ♦�i. I ♦ I ♦ I�I��I.� . , � ��i'!I�'y��y�I�I�I�1"�I�Y�I�I'V��-i-i r -. .r ;. `.,� -� _ � � S�i�i�j��j�I�I�� '��:��`�I��`:"' iiii '��-�-��' ►��►��i�i�.iar..i.�i�-i��c•��v��:�i�i�i�'-�:��_=�� ,.- . .. - . _ �I�I�I�I��.;�I��I �v��I��i� 7►��i�� •�� • I.I�I�I_�I��I��I��►�i��i��ii� ��i- /� ' +;� ►��p� ��ip�i� ',.,�j,��,/i,/, ///, ' ��..�.t�tc�C�'►�-��•►�:�i�i��ii.%i:�i� �. , i ♦��♦ ♦�� 1 �� / //// ///,,, '� � , `,,/ = /,♦♦♦•••♦•♦ ♦♦♦••••♦••< � � ►��♦ ♦��1 � ► � /////�//// % ��I��' • ... ..... / � • / / .�//////////'� ��I /� � ��:: �:::` 1t��i � � ►��i�i� �i�i�i�� .,►.�, /: i�/ � / �i� r i�. � , � , � � ,.,.�. .A.�.,,< :��;►�;� � /� � „ � � / � / � � �,� , I �.,,.��.,��:�,,...,� . � ,► �/ / / / , / / ��W.''.�.YYIY{�'�L'� - � - , / / / i' / / , /��.�l�Z��♦ :� � /� / / / / / / �� ♦�� , �,, �► ► ° - � �- � .. . � � . � . � ,� I�/ / � � � � � � � ..... ..... ��i►�IG/ �/ // /� // �/ / // // / / /i�i'i'i'i' i'i'i'i'i'r '�,i►�► /�/ / /� / �/ / /� / �/ / /►%%%%i �%%%i�%' •� � , .�,� �/ 1 I 1 � 1 ► . � . I �1 1 1 �..... ...r. � ,., ,� I � 1 1 ►.... .....« , 1 � 1 1 ..... ..... ��,,.,,,� 1 � /. � � � I / 1►.... ....., ��,,ti � 1 � • � � � ,•.•.•...• ...•.,•.• . ,:.�./��.�./��.�%/ � / �/ 1 � � ,.,.,.,.,.�,...,.,.� , , .��%�.��/ � / � ..... o.•... � � �I/�� ►o�o♦ ao�eer � .��.�.��I,��i�� ►��OOOO�t ' • �►!�!��i!�!4��:�:�� ` • _ . � � � i � � � � � � ' • ,. ..� � � :• � • • -i i •- •.. •: :� � • ► i • -• -• � •� � i � -i • � �. �, , • :. •:: •• i . - • � - i � �- � •i• � �- ,�, '� ' � . : � � • -i i �� • : • .• �.�.�� . ••: � . • _ �� I / �- . _ ' • ' ' . � : ��;� , . ./ 'I / I / • • 1 1 •1 1 --• g � � �, , � I I : I, • , • .. , � � . � -• • • / / •1 � • � PERFORMANCE STANDARDS (PART C) The Project is located in the Level 2 Flow Control area. The Level 2 performance requires that the developed condition's durations must match the predeveloped durations ranging from 50% of the two-year peak flow up to the full 50-year peak flow and also match developed peak discharge rates to predeveloped peak discharge rates for the 2-year and 10-year return periods (KCSWDM, Sec. 1.2. The Project was evaluated for onsite infiltration and dispersion of roof downspout runoff. The lots have insufficient space to allow for infiltration or dispersion of roof runoff. The Basic Water Quality Treatment goal is to remove 80% of TSS for flows or volumes up to and including the WQ design flow or volume. Conveyance criteria for the Project require that all new pipes be designed to convey and contain (at minimum) the 25-year peak flow. The proposed conveyance system was analyzed using the KCBW program, and is capable of conveying the 100-year peak storm without overtopping any structures or channels. (See Section V). FLOW CONTROL SYSTEM (PART D) The Site will utilize a detention pond meeting the Level 2 Flow Control Criteria. The King County Runoff Time Series (KCRTS) software was used to size the detention facility. The detention vault design information is included in this section. FLOW CONTROL BMP SELECTION Subdivision projects are required to mitigate for impervious surface equal to a minimum of 10% of each lot area by use of Flow Control Best Management Practices (BMP's). The reduced Impervious Surface Credit BMP as described in Appendix C, Section C.2.9 of the KCSWDM will be utilized for the Project. The maximum impervious surface allowed per zoning code for the total lot area (3.042 ac) is 2.281 ac using the maximum allowable build-out rate of 75% or 4,000 s.f. whichever is less. Lots 1-28 inclusive shall be restricted to a maximum impervious coverage equal to 65% of each lot area (1.997 ac). A restricted footprint covenant shall be recorded on the face of the final plat map. This satisfies the flow control BMP requirements in Section 1.2.3.3 and 5.2 of the 2009 KCSWDM. I ; � I� i j � I_ �p� � J '� � � j � r.�� f . � � s:_= ..i E:Li'.A!R. 02013 D. R. STRONG Consulting Engineers Inc. Piper's Bluff Plat Drainage Report vuy vi i�cnwi� i ' � i ' LOT NO. LOTAREA IMPERVIOUS AREA PER CODE IMPERVIOUS FOOTPRINT _ _ _ _ _ _ ' 1 5308 3981 3450 I � i .. 2 _. 4566 -.... __ 3425 _ _ 2968 3 .._— - - --`4 �, ' 3 � 4566 3425 ; 3543 ; __ __�__.__.._ _ _..�� -__ -----_.._�_.� I ` 4 ;� 4566 3425 3543 � _.. -----_ _.� �_.�_- --- _ _ _. _ -- � ; 5 4566 3425 2968 � � __.__. __-___ __ ._ ----. __ ___.__ ; 6 : 4566 3425 2968 ,�_._ __�_. _ --- .._—� ; 7 _� 4566 � 3425 2968 � 3 � __ _ . ..___ _ - _ . _. __.�_s3 8 4988 3741 3242 � �._ __te...._ __ � 9 � 4551 3413 2958 _____ __ __ ._ _ 10 ; 5197 3898 3378 _ _��_ ��_ � _ � ; 11 ! 4562 3422 _ � 2965 � . . ..�_.�.._... . . .. .. ._ _. . . . . _ � . ..... . ___._._�..y 12 ;� 4562 3422 2965 _ _ _ __ __ __ __._�� ` 13 � 4562 3422 2965 .�. �._. _ _ _..�� 14 4562 3422 2965 ; _ _ �_.__ __ _ _ -----_. ------ -- - ; 15 ; 4562 3422 2965 ` ;�.. _ __. _ ----- ---- _ __�_._____.� 16 � 4562 3422 2965 � __._ _ .- - ___�—��.i 17 i 5309 3982 3451 _ __ __. _ _ 18 : i----- 5223 _.__, 3917 � 3395 -_ _ ..____. _ � 19 '_ 4502 ~ 3377 � 2926 � _ _ _ __ _ .� 20 j 4501 '• 3376 2926 _ �._._.__ ___ __.__ _._ __ _...� __ 21 � 4500 3375 2925 _ _-_, _- - _.__ .� __ 22 ; 4500 3375 2925 ; _ _. _ _ ... �..__._ _i_ _- 23 � 4500 S 3375 2925 ___ _ _..��_.__ _. _ -- - 24 i 4500 � 3375 2925 ,� _ - -_ __ _ _- -- _- � .. __ _.. 25 4500 3375 2925 .�_. _ --_ ___ ----- _.__ _ ._ __----__�_� 26_ .; - 4979 3734 3236 � _...._, � 27 � 4958 � 3719 3223 � __.. _ _ _ . _ 28* 5725 4294 3428 *PER SECTION 5.2.1.1 OF THE KCSWDM 2009, RESTRICTED FOOTPRINT IS ESTABLISHED BY ' __ _ -- RESTRI CTI N G TH E FOOTP RI NT TO 4,000 SF LESS AN AREA EQUAL TO 10%OF TH E LOT AREA. �;2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 21 of 43 Drainage Report City of Renton FLOW CONTROL FACILITY DESIGN OUTPUT �etent�or/Detention Facility Type of Facility: Detention Pond Side Slope: 3.00 H:_�� Pond Bottom Length: 33.00 f� Pond Bottom Width: 16.00 ft Pond Bottom Area: 528. sc. ft Top Area at 1 ft. FB: 13038. sq. ft 0.299 acres Effective Storage Depth: 14 .0� ft Stage 0 Elevation: 410.00 �t Storage Volume: 69132. cu. ft 1.587 ac-ft Riser Head: 14.00 ft Riser Diameter: 18.00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 0.88 0. 079 2 10.00 1.50 0. 122 4 . 0 � 3 10.70 "-.�0 �. i;9? 4 . 0 Top Notch Weir: None Outflow Ratina Curve: No:�e S�age Elevation Storage Discharge Percolation Surf Area (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) (sq. ft; 0.00 410.00 0. 0.000 0.000 0.00 528 . 0.01 410.01 5. 0.000 0.002 0.00 531. 0.02 410.02 11. 0.000 0.003 0.00 534 . 0.03 410.03 16. 0.000 0.003 0.00 537. 0.04 410.04 21. 0.000 0.004 0.00 540. 0.05 410.05 27. 0.001 0.005 0.00 543. 0.06 410.06 32. 0.001 0.005 0.00 546. 0.07 410.07 38. 0.001 0.006 0.00 599. 0.35 410.35 203. 0.005 0.012 0.00 635. 0. 62 410.62 387. 0.009 0.017 0.00 724 . 0. 90 410.90 603. 0.014 0.020 0.00 822 . 1.17 411.17 838. 0.019 0.023 0.00 921. 1.45 411.45 1111. 0.026 0.025 0.00 1030. 1.72 411.72 1404. 0.032 0.028 0.00 1140. 1. 99 411.99 1727. 0.040 0.030 0.00 1256. 2.27 412.27 2096. 0.048 0.032 0.00 1381. 2.54 412.54 2486. 0.057 0.033 0.00 1507. 2.82 412.82 2927. 0.067 0.035 0.00 1643. 3.09 413.09 3389. 0.078 0.037 0.00 1780. 3.37 413.37 3908. 0.090 0.039 0.00 1928 . 3. 64 413.64 4448. 0.102 0.040 0.00 2075. 3. 92 413.92 5052. 0.116 0.042 0.00 2234 . 4.19 414.19 5676. 0.130 0.043 0.00 2392 . 4.47 414.47 6369. 0.146 0.044 0.00 2561 . 4.74 414.74 7083. 0.163 0.0�6 0.00 2730. 02013 D. R.STRONG Consulting Engineers Inc. PipePs Bluff Plat Page 22 of 43 Drainage Report City of Renton 5. G1 �1�.01 �899 . 0. "�_80 ��. 047 0.�0 29�5. 5.29 415.2� �683. 0. 199 0.048 0.00 3091 . 5.56 415.56 9543. 0.219 0.050 0.00 3276. �.84 415. 84 10487. 0.241 0.051 0.00 3473. 'o. 11 416.11 11451. 0.263 0.052 0.00 3668. 6. 39 416.39 12507. 0.287 0.053 0.00 3877. 6. 66 416. 66 13582. 0.312 0.054 0.00 4083. ' 6. 94 416. 94 14755. 0.339 0.055 0.00 4302. i .21 417.21 15946. 0.366 0.056 0.00 4519. '� 7.49 417.49 17244. 0.396 0.057 0.00 4750. 7.76 417.76 18557. 0.426 0.058 0.00 4977. 8.03 418.03 19932. 0.458 0. 060 0.00 5210. 8.31 418.31 21425. 0.492 0.061 0.00 5457. 8.58 418.58 22931. 0.526 0.062 0.00 5701. 8.86 418.86 24564. 0.564 0.063 0.00 5959. 9. 13 419.13 26207. 0.602 0.063 0.00 6213. 9.91 419.41 27984. 0.642 0.064 0.00 6482. 9.68 419. 68 29770. 0. 683 0.065 0.00 6747. 9. 96 419.96 31698. 0.728 0.066 0.00 7027. 10.00 420. 00 31980. 0.734 0.066 0.00 7068. 10.02 420.02 32122. 0.737 0.067 0.00 7088. 10.03 420.03 32192. 0.739 0.068 0. 00 7098. 10.05 420.05 32335. 0.742 0.071 0.00 7119. 10.06 420.06 32406. 0.744 0.074 0.00 7129. 10.08 420.08 32549. 0.747 0.078 0.00 7149. i0.09 420.09 32620. 0.749 0.083 0.00 7160. 10.11 420.11 32764. 0.752 0.087 0.00 7180. 10.12 420.12 32835. 0.759 0.088 0.00 7190. 10.40 420.40 34889. 0.801 0.106 0.00 7479. 10. 67 420. 67 36947. 0.848 0.119 0.00 7764. 10.70 420.70 37180. 0.854 0.120 0.00 7795. 10.71 420.71 37258. 0.855 0.121 0.00 7806. 10.73 420.73 37414. 0.859 0.122 0.00 7827. 10.74 420.74 37493. 0.861 0.125 0.00 7838. 10.76 420.76 37650. 0.864 0.128 0.00 7859. 10.77 420.77 37728. 0.866 0.133 0.00 7870. "-0.79 420.79 37886. 0.870 0.138 0.00 7892. 10.80 420.80 37965. 0.872 0.141 0.00 7902. 10.82 420.82 38123. 0.875 0. 142 0.00 7924. 11.09 421.09 40302. 0.925 0. 167 0.00 8216. 11.37 421.37 42646. 0.979 0.185 0.00 8525. 11. 64 421. 64 44988. 1.033 0.201 0.00 8828. 11. 91 421 . 91 47413. 1.088 0.216 0.00 9136. 12. 19 422. 19 50017. 1.198 0.228 0.00 9461. 12. 46 422. 46 52614. 1.208 0.241 0.00 9780. 12.74 422.74 55400. 1.272 0.252 0.00 10117. 13.01 423.01 58175. 1.336 0.263 0.00 10446. i3.29 423.29 61149. 1.404 0.273 0.00 10794 . 13.56 423.56 64109. 1.472 0.282 0.00 11134 . 13.84 423.84 67277. 1.544 0.292 0.00 11493. 14.00 424 .00 69132. 1.587 0.297 0.00 11700. 14. 10 424 .10 70309. 1.614 0.762 0.00 11831. 14 .20 424 .20 71498. 1.641 1. 610 0.00 11962. 14 . 30 424 .30 72701. 1.669 2.710 0.00 12094 . 14 .40 424.40 73917. 1.697 4.010 0.00 12227. 14 .50 424.50 75146. 1.725 5.480 0.00 12360. 14 . 60 424 .60 76389. 1.754 6. 910 0.00 12494 . �2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 23 of 43 Drainage Report City of Renton i 14 .70 �24 .70 77645. 1.782 7.440 0.00 12629. 14.80 424 .80 78915. 1. 812 7. 930 0.00 12765. 14. 90 424.90 80198. 1. 841 8.400 0.00 12901. 15.00 425.00 81495. 1.871 8.840 0.00 13038. 15.10 425.10 82806. 1. 901 9.260 0.00 13176. 15.20 425.20 84130. 1. 931 9. 660 0.00 13314 . 15.30 425.30 85469. 1. 962 10.090 0.00 13453. 15.40 425.40 86821. 1.993 10.910 0.00 13593. 15.50 425.50 88187. 2. 025 10.760 0.00 13734 . 15.60 425.60 89568. 2.056 11.110 0.00 13875. 15.70 425.70 90962. 2.088 11.440 0.00 1401?. 15.80 425.80 92371. 2. 121 11.770 0.00 14160. Hyd Inflow Outflow Peak Storaae Target Calc Stage Elev (Cu-Ft) (Ac-Ft) 1 1.88 ******* 0.28 13.49 423.49 63386. 1. 455 2 0. 93 0.31 0.25 12.72 422.72 55199. 1.267 Z r, y l• 3 1. 12 ******* 0.22 11. 94 421. 94 47731. 1.096 4 0. 93 ******* 0.22 11.94 421.94 47716. 1.095 5 0.99 ******* 0.16 11.05 421.05 39968. 0. 918 6 0.58 ******* 0.10 10.23 420.23 33669. 0.773 7 0.76 ******* 0.06 9.39 419.39 27883. 0. 640 8 0.82 ******* 0.06 8.21 418 .2? 20902 . �. 48� ---------------------------------- Route Time Series thro�agh Facili�y Inflow Time Series File:dev.ts= Outflow Time Series File:rdou� Inflow/Outflow Analysis Peak Inflow Discharge: 1. 88 CFS a� 6:OC on Ja-� 9 in Year 8 Peak Outflow Discharge: 0.280 CFS at i4 :00 on Jan 9 i~� Year � Peak Reservoir Stage: 13. 49 Ft Peak Reservoir Elev: 423.49 Ft Peak Reservoir Storage: 63386. Cu-Ft . 1. 455 Ac-Ft �'low Frequency Analysis Time Series File:rdout.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 0.251 2 2/09/O1 21:00 0.280 13.49 1 100.00 0. 990 0.064 7 1/07/02 4:00 0.251 12.72 2 25.00 0. 960 0.217 3 3/06/03 22:00 0.217 11. 94 3 10.00 0. 900 0.061 8 8/26/04 7:00 0.217 11. 94 4 5. 00 0.800 0.095 6 1/08/05 3:00 0.163 11.05 5 3. 00 0.667 0. 163 5 1/19/06 0:00 0.095 10.23 6 2.00 0.500 0.217 4 11/24/06 8:00 0.064 9.42 7 1.30 0.231 0.280 1 1/09/0�? i9 :00 0.061 8.21 8 1. 10 0.091 . _ , � s2013 D. R. STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 24 of 43 Drainage Report City of Renton I il Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS o o % 0.004 37253 60.752 60.752 39.248 0.392E+00 0.011 2181 3.557 64.309 35. 691 0.357E+00 0.018 2049 3.341 67. 650 32.350 0.323E+00 0.025 2774 4 .524 72.174 27.826 0.278E+00 0.032 2761 4.503 76. 676 23.324 0.233E+00 0.039 3214 5.241 81. 918 18.082 0.181E+00 0.046 3815 6.221 88. 139 11.861 0.119E+00 C.053 2842 4.635 92.774 7.226 0.723E-01 0.060 1950 3.180 95. 954 4.046 0.405E-01 0.067 1952 3.183 99.137 0.863 0.863E-02 0.074 34 0.055 99.193 0.807 0.807E-02 0.081 20 0.033 99.225 0.775 0.775E-02 0.088 43 0.070 99.296 0.705 0.705E-02 0.095 57 0.093 99.388 0. 612 0. 612E-02 0. 102 44 0.072 99.460 0.540 0.540E-02 0. 109 51 0.083 99.543 0.457 0.957E-02 0. 116 51 0.083 99.627 0.373 0.373E-02 0.123 34 0.055 99. 682 0.318 0.318E-02 0.130 9 0.015 99.697 0.303 0.303E-02 0.137 6 0.010 99.706 0.294 0.294E-02 0.145 10 0.016 99.723 0.277 0.277E-02 �.152 12 0.020 99.742 0.258 0.258E-02 0.159 19 0.031 99.773 0.227 0.227E-C2 �.166 19 0.031 99.804 0.196 0.196E-02 0.173 15 0.024 99.829 0.171 0.171E-02 0.180 14 0.023 99.852 0.148 0.148E-02 0.187 7 0.011 99.863 0.137 0. 137E-02 0.194 12 0.020 99.883 0.117 0.117E-02 0.201 9 0.015 99.897 0.103 0.103E-02 0.208 10 0.016 99. 914 0.086 0.864E-03 0.215 10 0.016 99. 930 0.070 0.701E-03 0.222 16 0.026 99. 956 0.044 0.440E-03 0.229 10 0.016 99. 972 0.028 0.277E-03 �.236 4 0.007 99. 979 0.021 0.212E-03 0.243 4 0.007 99. 985 0.015 0.147E-03 0.250 6 0.010 99. 995 0.005 0.489E-04 Duration Comparison Anaylsis Base File: predev.tsf New File: rdout.tsf Cu:off Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Ci'�o�i Base New oChange Probability Base New oChange 0.069 I 0. 94E-02 0.83E-02 -11. 6 � 0.94E-02 0.069 0.066 -4 . 5 0.088 � 0. 62E-02 0.70E-02 13.1 I 0. 62E-02 0.088 0.095 7. 4 0.107 � 0.49E-02 0.48E-02 -1.3 � 0.49E-02 0. 107 0.107 -0.3 0.126 � 0.37E-02 0.31E-02 -16.4 � 0.37E-02 0. 126 0.117 -7.0 0.145 � 0.28E-02 0.28E-02 -2.3 I 0.28E-02 0.145 0.142 -1. 6 0.163 I 0.22E-02 0.21E-02 -7.4 I 0.22E-02 0.163 0.160 -1.8 0.182 � 0.15E-02 0.15E-02 -l.l � 0.15E-02 0.182 0.182 -0.3 0.201 � O.10E-02 O.10E-02 1. 6 I O.10E-02 0.201 0.202 0. 6 0.220 � 0. 62E-03 0.49E-03 -21. 1 � 0.62E-03 0.220 0.217 -1.5 0.239 I 0.34E-03 0.18E-03 -47.6 � 0.34E-03 0.239 0.226 -5.2 0.257 � 0.21E-03 O.00E+00 -100.0 � 0.21E-03 0.257 0.238 -7.5 ��2013 D. R.STRONG Consulting Engineers Inc. PipePs Bluff Plat Page 25 of 43 Drainage Report City of Renton G.276 I 0. 16E-03 O.00E+00 -100.0 � 0. 16E-03 0.276 0.243 -12. 1 �.295 I 0.11E-03 O.00E+00 -100.0 I 0.11E-03 0.295 0.246 -16.5 0.314 I 0.16E-04 O.00E+00 -100.0 I 0.16E-04 0.314 0.251 -19. 9 h7aximum positive excursion = 0.007 cfs ( 8. 60) occurring at 0.081 cfs on the Base Data:predev.tsf and at 0.088 cfs on the New Data:rdout.tsf Maximum negative excursion = 0.063 cfs (-19. 9°) �' occurring at 0.314 cfs on the Base Data:predev.tsf and at 0.251 cfs on the New Data:rdout.tsf ---------------------------------- ' �oute Time Series through Facility =nflow Time Series File:dev.tsf �utflow Time Series F' ' �: r�,�: :- =rflow/Outflow Analysi Peak Inflow Discha- : . : �eak Outflow Discharge: U.2'o0 CFS at -�4 : �u on �an 9 in Yea- Peak Reservoir Stage: 13.49 Ft ?eak Reservoir Elev: 423.49 Ft _e�:� Reservoir Storage: 63386. Cu-=t . 1.455 P_c-F Flow Frequency Analys-s Time Series File:rdout.tsf ?roject Location:Sea-T�-� ---Annual Peak Flow Rates�--- Fl_.>: �~ - -- , _ '�� ---�!��i� -- Flow Rate Rank Time of reak - - ?ea�s - - �an;� Return Pro� (CFS) (CFS) (ft) Period 0.251 2 2/09/O1 21:00 0.280 13.49 1 100.00 0. 9°G 0.064 7 1/07/02 4:00 0.251 12.72 2 25.00 0.96� 0.217 3 3/06/03 22:00 0.217 11. 94 3 10.00 0.900 0.061 8 8/26/04 7:00 0.217 11. 94 4 5.00 0.800 0.095 6 1/08/05 3:00 0. 163 11.05 5 3.00 0. 667 0.163 5 1/19/06 0:00 0.095 10.23 6 2.00 0.500 0.217 4 11/24/06 8:00 0.064 9.42 7 1.30 0.231 0.280 1 1/09/08 14 :00 0.061 8.21 8 1.10 0.091 Ccmputed Peaks 0.270 13.21 50. 0� 0, ��0 Flow Duration from Time Series File:rdout.tsi Cutoff Count Frequency CDF Exceedence ProbGbility CFS ° ° ° - 0 0 � 0.004 37253 60.752 60.752 39.248 0.392E+00 0.011 2181 3.557 64.309 35. 691 0.357E+00 0.018 2049 3.341 67.650 32.350 0.323E+00 0.025 2774 4.524 72.174 27.826 0.278E+00 0.032 2761 4.503 76.676 23.324 0.233E+00 0.039 3214 5.241 81. 918 18.082 0.181E+00 0.046 3815 6.221 88.139 11.861 0.119E+00 0.053 2842 4.635 92.774 7.226 0.723E-01 0.060 1950 3.180 95.954 4.046 0.405E-01 0.067 1952 3. 183 99.137 0.863 0.863E-02 0.074 34 0.055 99.193 0.807 0.807E-02 0.081 20 0.033 99.225 0.775 0.775E-02 ��2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 26 of 43 Drainage Report City of Renton 0. 088 43 0.070 99.296 0.705 0.705E-02 0.095 57 0.093 99.388 0.612 0.612E-02 0. 102 44 0.072 99.460 0.540 0.540E-`i2 0. 109 51 0.083 99.543 0.457 0.457E-02 0.116 51 0.083 99. 627 0.373 0.373E-02 0. 123 34 0.055 99.682 0.318 0.318E-02 0. 130 9 0.015 99.697 0.303 0.303E-C2 0. 137 6 0.010 99.706 0.294 0.294E-C2 0. 145 10 0.016 99.723 0.277 0.277E-�� 0. 152 12 0.020 99.742 0.258 0.258E-02 0.159 19 0.031 99.773 0.227 0.227E-02 0.166 19 0.031 99.804 0.196 0.196E-02 0. 173 15 0.024 99.829 0.171 0.171E-G2 0. 180 14 0.023 99.852 0.148 0.198E-C2 0. 187 7 0.011 99.863 0.137 0.137E-�2 0.194 12 0.020 99.883 0.117 0.117E-02 0.201 9 0.015 99.897 0.103 0.103E-02 0.208 10 0.016 99.914 0.086 0.864E-G3 � 0.215 10 0.016 99.930 0.070 0.701E-03 0.222 16 0.026 99.956 0.044 0.440E-�3 0.229 10 0.016 99.972 0.028 0.277E-Oj 0.236 4 0.007 99.979 0.021 0.212E-G3 0.243 4 0.007 99. 9R5 �. 0�5 0. 14?_-03 0.250 6 0.010 99. � DURATION ANALYSIS N f^ o rdo.dd�s o R targetdur • m 0 v 0 0 � d LL U m � rn � o LU N � N O m O � O O O O 'I�s 1�� 1� 2 1�-1 � „�C Probabi�iry 6c.eedence C�2013 D. R. STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 27 of 43 Drainage Report City of Renton f ' . I WATER QUALITY TREATMENT SYSTEM (PART E) _ The Project is located in the Basic Water Quality Treatment area. The treatment goal is 80% removal of total suspend solids for a typical rainfall year, assuming typical pollutant concentrations in urban runoff. A 96-inch diameter Stormfilter manhole with (13) 18-inch cartridges will will provide 0.22 cfs of treatment flow rate. Stormfilter final sizing per CONTECH Stormwater Solutions, Inc is included in Section X. G�2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 28 of 43 Drainage Report City of Renton FIGURE 7 DETENTION & WATER QUALITY FACILITY DETAILS ;__; 'I � i I I ^n ' 1 l.... � .r r I � C�2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 29 of 43 Drainage Report City of Renton NE 1/4 SEC710N 10, TOWNSH/P 23 N, RANGE 5 E, W.M. _ , PIP�R'S BL UFF �' �. �.�� _ . ,�� ,,..,�� -___ .., __..___. '__'.____ ._____. ... .___._— ... – _._'.______.._. . __. .._.._ .... . �. Y '� 1 i?2 BM 421.00 ,, C6 1I STAifOY CB 16 7TPE '3�'/ .___- ___.__- +_. . . , . _,__.-_ ... � pB.D1 R UFT �.C[WiRlX SiRI/C7UPE. ' t , . l � . G�� HW{2175 �l1FT SfA71QN STA 16+.lflIB,�30.8J R -� _ I � � �41@73 �.P�+�NS FD14 UE7AN5� 131[�11RE0 . Y"��;` _ . i ' � � � � ; .. ! _ ... - _- �. . 41RQ0 _ �__ t�J�. Sy '.. . ' . f�1I, /'T[�'_G� '. . __. ._ .,__- — _. � \ � ; , : : _ , � - , �fiL Si.CPf'�. �. ' ' � ; : .o� , 78�RI4R _..,__ _ �• .., r,�p�.....\...._..o _._-_-__.___-- ;-.- ___.� . lPf T)PE 961 ��_ . . s � � " 7W t.SEQO : � �, .. �.� '�� '`. 1J 8G�� Q6diARGE�d/1[ET � BW A7200 . � i 't-� '..'. � \� +��s��.i+ �' STA /8+44.1 6J R�� _H-�7MYl0 IX/ARRY.� . � WK!UE3DYtD BY OA4RS � I � �� , .. .. o o'� Rtll 4?'.� - SPU91 PAD YtD � i j IE CUf I07.7U .. _.. ._.. i . ! ' �\ - - LIEINLS SHEFT Ci! ... �. ..____ �_ . .._. ______.. �_—_. _�____._ i - , ,--__.— I . I • • .. , __�_ , .__. . ; . ` -- . ___ - - ..- .. � � ' I '. . i � i .�� i� - - -BW��QO �' . Z � ' �\I � i - I i . . ;..: � 9M12f.50 . -_ -- pr__. ._. - __-_ - � � . \ PRCY�OSED fP05IfD OPA11E' OOS7N�AG WAQE i � _ .. � w J ` ! I 'r ro rt�ne ``. Nsr c� g� �• ►) '� �'."' o m �; �_ ^ ! � rE aa S� �+Ze - 4�,p��,�' r�� iraE `s�i ��a : , i 1 nv � BW � _.— __-__- ._ _'._. _ . .- _.. __. _ ._..._. a _ . . j � —_"_–__� ; .. - , 0 F4FRGEMC�Yfl OL6tFL01/'R .. � ..i � \.. — , / \ .� � _ l , . � ��'RAl 42{.47 u � - � - �\ _ ,:\ I li / —...I_ � � '- .... . ' i ' , i � �_�—_— J I . , :. � . �E�N b7.7D , \•._. ' �. u . TW s28.00 �OfIT�07.70 0. - ' �i+r a�vnav-�zaoo_ _ - i I I � 4�� I �w s�.on . TR.4CT B - \� � , �—_�-___ .._, ..-_ I ._'�'---_ { — � � ;,, . ' � .. .;�: .��.. 11- Id/L�E�. . � \ / NGP � � � �,. � '� ; �: I : — _ _ : � . i�., - : -- ��' -.q. .. ...[ �..:. OQPDI M5 ', �i4)IOgt � I __ �- w I . T � �' � . I:�� +; - ,:•.L�RU - s..- 7 . ' i _ , : � i � . � ��x_a -: � ..,, : �: : ` - I �', ti LF 7B LLPE � . �_ i ' � � . �� 18'/IKEI Q �O RQD.�.��8 '.� � �,__ _�— �_-_. ._..___ .-_._._ __.__f . ..__.'-__._ __--_�` FRON VA(R7 o r� XJb� . . " �l � ; i ; � � E-47Q00 !G PGtl'�D MET ''� ;�� . 1 � � � � II I 'I �� ,�,/0�,�,: ,,\ . i � � CB 16 PLAN VlEW a., c,- e :;� �&�sN a,�o.: r `•��,\`', . ; SECT�ON A-A � r-z s�. � __ , � . . . -—- - _ _- --I - _- -�__ ___ _--- -- ---- ' s x�c��z � , � 4 us ' ' � � � .- l ' �' �� - --...._ < . � 1 I II � A�,� � 'v ra'r Fxcw � I i � _�� COUPCNG C1R F[AMOE ' �� .� , 4f DR 9EEf C3 �y � �� .___ __-.._ �_.. � __. �.. ....__._--. ' I �I � I.� ��.., �:.� - POMm PUR£f � � f i ! �� ' I� w/m�9+ ac, m�cr ' o+m o+�o aac i+zo r -- - � ` Bouvn.wr __ _ _ __._. ': �-sraao , ,ao �roo � , � _i ; aic£r • � '� i .. . � � �t raEr�ieaiuc w�ii � ' ---- - -- --- ------_._ - _ - , ,, ��: � � I s, , �A � _ sg�q.ws , � � ; , � �� , I i I 5 6 . k�� -- 3 ' � - � I7f q.rt . - � � Y I ¢ � � . I �� + - �1 � . �; __ _ ��.� _ �� . . N o :.: �� , � ; � i �„�,�� , � , � � > = _ .- _ . � � � � �� '�� ' w��mszw�,w'�w/� �OW RESTR/CTOR DETAlL ' � � � � ' �07�� -�a�am-aat�.tt cF , � � o. �.so a�r. wc.wrowam�m'u�'c� i - LQf7CP/C BQ� N1S �I .,� !: •�i � �. .___ 7Q , �' ... ... I .___. -_ __......-- i----___ . . ._.- ---------- � 7LTIFMIf9�Dl7UDE) � ..� . ! _ , _. _, - �SFE 9/EFI C!J AMD S .__ _..._. .. � PLANS FLR DETAQ.S \ - ' � � PRQ°OgD fM3m GRA�' - SJ � - ... � . �... J7Y IZGDO . . \ �'�,� NOTES: �g� � , ew�os.so ... � , ` �� . �-., , � --__ _ ___- - ____ ---- - _ ._ a- wx� t.�9gs.un sa�rs vm a�w � y �-� �S_,�,.� � _ . � ` _ -- -� TW 4M00 � � 2 OUftET CAPApiY' t0�ffi P£A/(h20M L —J-.��-- _- _ . . BW IOA50 ��\�� -"- \ SEF 57RfkMRAL �Np�� 3£XC�PT AS SlOMN dt NDiED.f.10R 9!A!1� s � /� � _ �;,�"�v �, ? OVfJM�79WG PUNS '.. Cd157Rf/C1ID 1N ACCCi4DANCE M7H 7NE N n I � �.,.. IdEOCYPE7/fNJS Fq4 GTt7f 8A9MI TYP£2 60'WN. : `''�.+•� � . DI�11f. \ I . � ..__ .._... __ _.__. — ...�_-�_ .. . . .. . __ .... , •+ � � ' � �I TOP lF DETEN7IAV�i1AQ0� �. .• �. , I.PoPE.9iPPLrf75 AI�D AESTR7C7UR/SfPARA7fA4 9U11 BE O�SAYE W7FR'K ANO HE N�1D/LYOED AT �.END IG�1L . i - � - - T - - t� a'un.¢sr�avic er a/e ouW,srnwttss s�m �r+aao ai tf rz'�ttrE �cr muvo.vtr , � � � � - w a�.wsaw eacrs ae om¢nm r x iwu _ e zs.eas rml, �� : ' avF�r-�z/�s' S n+t�rcvr�rr.vrarae swt eE - , `• TR.4CT C'� � � � • __ _ _...._. ,_ +�o _- _- __� � _ _ . _ --, i - ... F�aa�rw�o�ar.aso•uuiwur ar.a�s' ' � 4��'� ALfAGV�D 51t�.04.Q64�GALVAMgD 57FII.PFE 1 7REEPRESERYA7KJMITRAC7 ` . /N APPpPDM�MfAf AA4RO Y 34 W04 Y tD7, /1. ' 499BW:R , \ an`�r-�+/'1' ,wv w z�� cu.va�srm suu an� I - �. Y. �n�xr�. � RT � �e-e..Er : �.a.aw '��, 1 ., 7fZ4cT D" �Y�,.` `'\\ . __ __ I ._ _------ � � �r��sr�'mcar7O.w�c�szn - _ _ ' . �.. JRMI�QPhEWAY. ��f'/`,ti ., \ ... IX.WRI/ir17ED IEIAL HPL p7(iRd/7fD HR/Af£ . . ` •, . , �e�ourzer eEzi.a�ac�voff�r� �s�HN�io�s v nun sa) '. ;: ' � _ __ _ r- raoo � a�txr-a¢tn z n�wene,¢m�e smr aF n,� ; .'` � �r p.ws rr�snncrc�eisr,�wvrn swiu aE nf s,u�a,u� POND NOTFS: � ' - � � FKYtlZOVTAL OURET PPE M7H AN 8'MN. 1.A.^.CESS GATF SNALL Bf LOCATID A7 ACCESS Rd10 ANO SHAL.HA1f COCXWC ` _.TOW C!�SSQMEM 51bPACE��fQ00 i : . .. 2� � 18'I OI�Pog7t AS A�E � f70. .._. ._._. __ ....... _�—_...__— —. ___— Q.�0950 LY'W. A/ECHAN/SN. - .. � i o I'SECTICW LI�PFE � '.� AT7AfilID BY G�19�7ID 8 FRAM£MO UME7t pt 51fP5 Q�FSET 50 7NAT' Z PLACF'STQPA/WA7ER STORACE PQVD'9GMACE AS PER p7Y RECQVAff710A71QV �' BA�N l�ALLOW RE710YAL A[XEANOUT GA7E!S N9BLE FRQtl 701? B.Q/AfH POWY�A(1�fS(SEAR C1c PoSER ANO � �I � CQ/ Q)R RQO f Y 2'IMP/ R67R1CTOIP PUIE [XEANOlIT GITE ' R SECADN B-B � I �ao e�Ar s aEob , ws�uo�o�°irr m� c rn�rs a�a�axm .� � _ __ _ ___ N O RT H ' � __ _ _ __.. Fae rmncu . �w a�wFru.ovnFr vvE cnvwEcrs m oomvr � � u�r»'/ L0'A0�'F� °f�"�P1PE7°""'E�07H GRAPHIC SCALE DRAWINGS NOT APPROVED ' m�a��xaes o.a Enuu.ro�aaaE Aa�ss r/s- �i 01�5J 5`� ra�wen-aeFrce aso�s��r ae coca�n tis �-� 20 `0 FOR CONSTFiUCT10N UNLESS RECOMMENDm � _ __ -- -� __ _ `-- -- - �aa��a�sar ar�rr ro�sst� 'HORiz"=��. STAMPED OR SIGNED APPROVED FOR nPPRovn� II � °'°° °N° o«� �+� 0 2;5 5 � BY THE REVIEWING AGENCY BY ' CB 16 CON7ROL S7RUC7URE 'r i � � NTS 11NCH=5FT. BY � �,Jt oc i��UOF, VERTICAL � 9 ' � .� g arisvin caraN�s � ��s NOTm ""';°",H� c, ,� CITY 0� oe-sa-�s Ca12WorkigDeyeBeforeYouDip D p � � REN?ON PIPER'S BLUFF � � 1-800-424-5555 � � D �`'��`�S� 'M`"�'� POND SECTION AND DETAILS � .. ,s� mez � fOB�NNE7lEM1R.ffof pMQAlA,WAPA0.3.Y f�� n� ` Ul�dieeUdx�oudLocefionCenix �'�� o�xxen�omFtzs.ez7.7vv yN i .*.�..�u � Plannirg/Building/Public Works Dept. �5 � (D,MT.PDpRWN �OYAL su Kcaowti. s�m: a � y �+'�� NO. R=ViS10N BY DATE APPR � C13 �18 A- NNNNAA ,,�, e Determining Number of C%.►=NTECH Cartridges for Systems ENGINEERED SOLUTIONS Downstream of Detention CONTECH Stormwater Solutions Inc. Engineer: JHR Date 618/2012 Site Information Project Name Hazen Project State Washington Project Location Renton Drainage Area, Ad 5.06 ac Impervious Area,Ai 3.65 ac Pervious Area,Ap 1.41 % Impervious 72% � Runoff Coefficient, Rc 0.70 Upstream Detention System � Peak release rate from detention, Qrelease peak 1.29 cfs Treatment release rate from detention, Q��ease treai 0.09 cfs Detention pretreatment credit 50% (from removal efficiency calcs) Mass loading calculations Mean Annual Rainfall, P 36 in Agency required % removal 80% Percent Runoff Capture 90% Mean Annual Runoff,Vt 416,111 ft' Event Mean Concentration of Pollutant, EMC 60 mg/l Annual Mass Load, Mtota� 1557.68 Ibs Filter System Filtration brand StormFilter Cartridge height 18 in Specific Flow Rate 1.0 gpm/ft2 Number of cartridges-mass loading Mass removed by pretreatment system, MP� 778.84 Ibs Mass load to filters after pretreatment, MPa�� 778.84 Ibs Estimate the required filter efficiency, Efi�ter 0.60 Mass to be captured by filters, Mfner 467.30 Ibs Allowable Cartridge Flow rate, Q�rt 7.50 Mass load per cartridge, Mcart(Ibs) 36.00 Ibs Number of Cartridges required, Nmass 13 Treatment Capacity 0.22 cfs Determine Critical Sizing Value Number of Cartridges using Q�,ease<<ear, Nflo,,,, 6 Method to Use: MASS-LOADING SUMMARY Treatment Flow Rate, cfs 0.22 Cartridge Flow Rate, gpm 7.5 Number of Cartridges 13 1 of 1 � � CONTRACTOR TO GROUT 70 � W FINISHED GRADE 2 GRADE RING/RISERS � y � � STORMFIL7ER DES/GN NOTES W � GRADE R7NG/RISERS � i N STORA-fFlLTER TREATI.fENTCAPACITY IS A FUNCTION OF THE CARTRIOGE SELECTION AND THE NUMBER OF CARTRIOGES. TN.E C9 C'1 STANDARD MANNOLE STYLF !S SHOWN W1TN TN£ MAXIMUM NUMBER OF CARTRJDGES (14). ✓OLUMf SYST£A�f IS ALSO Q � , � � ' LVAJLABLE WITH MAXlk1UM 14 CARTRIDGES. � j °� � � i �%.�� ¢96"'MANHOLE STORMFILTER PEAK HYDRAUUC CAPAClTY IS 1.8 CFS. IF 7NE SITE CONDITIONS EXCfEO 1.8 CFS AN V� t� "� Q � UPSTREAM BYPASS STRUCTURE IS Rf0U1R£D. � � � � � • _ ' I O U � � y� � � : , " . LARTRIDG£ SELECTION a CARTR�OG£ HEIGHT 27" )8'" LOW OROP � '` ( �1 RECdMM�4'JcD NYURAULIC DROP (H 3.05" 2.3' 1.B' K � � FCOATABLES SPECIFlC FLOW Rti7E m sf 2 pm/ft 1 pm /t 2 pm (t 1 pm/lt 2 pm/ff 1 pm/ft � W `� BAFFLE CARTRIGGE FLOW RATE m 22.5 T 1.25 15 7.5 10 5 � 2 � � O W � � �� S1TE SPEC/F1C � ' 2� DATA REQU/REMENTS ti 4i — S7RUCTURE ID * o�� e \ WATER OUAL7TY FL0'r�'R�;7� �cls` 0.090 78" !NL£T PIPE �?� ? �-y � � PEAK FLOW RA7E cfs 1.29 c�W W _x x� R£7URN PERlOD Or" PEAK FLOW s 100 j�= - ---:�r.z-�> , OF CARTRlDGES REOUJRED 13 Q?o ~ '� � � CARTRIOGE FLOW RATE 7.5 a= �C�YNTECH''"� � �`,o I MED1A TYPE CSF, PfRLlTE, ZPG, GAC, PHS z i 2 i' - _ �I � i ` � PJPE DATA: l.E. MATERIAL DIAMETER IP1LfT PIPE 1 470.00 LCPE 18-INCNES . � � _ �3" INLET PIPE 2 s s OUTLET PlPE 407.70 LCPE 18-INCHES FIL TER CARTRIOG£ —� ,. RIM ELEVATIDN OUTLET SUMP FLO'N K!T ANT1-FLOTATION BALLAST W/DTN HEIGHT , HOP� rs" ourcEr RrsER FRAMEAND COVER ` NOTES/SPEClAL REOUlREMENTS: SECTION A A (DlA�rEN R SVARI�S} N.L S. • PER ENGiNEER CF RECORD . � � lll O • GENERAL NOTES: � Q � � OUTLET 1. CONTECH TO PROVlDE ALL MATERiALS UNLfSS NOT["D OTHfRW15E. I� Z � SUMP 2. O/A�ENSIDNS MARKfO WlTH () AR£ REFERENCE D/MENS/ONS. ACTUAL DlMENSlONS MAY VARY. � W �J Z , �. FOR S1TE SPEClFIC ORAWTNGS W/7H DfTAILED VAlJLT OIA�fENS10NS AND Wf1GHTS, PLEASE CONTACT YOUR CONTEC,Y � O ¢ _ ENGINEER£D SOLUTIONS LLC REPRESENTATlVE. www.contechES.com I� 4. STORMFlLT£R WATER OUALITY S7RUCTUR£ SHACL B£IN ACCORDAMCf W1TH ALL DES/GN DATA AND INFORMATfON � � I � C O N T A 1 N£D 1 N T H I S O R A W 1 N G, y W Q � A �{ 5, STRUC7URf SHALL MEET AASHTO N,S20 LOAD RATING, ASSUMlNG EAR7H COVER OF 0' – 5' AND GROUNOWATER � � � ELEVATlON AT, OR B£LOW, THE OUTLET PIPE 1NVERT ELEVATION. ENGINE£R OF R£CORD TO CONFIRM ACTUAL � l� � Z • �� _ �o _ GROUNDWAT£R ELEVATION. CASTINGS SHALL M££T AASH70 �A306 AND BE CAST WlTN TyE CONTECH LOGO. � i o E. FILT£R CARTRlDGES SHALL 8E MEDIA–FlLLED, PASS/Vf, S/PHON AC7UA7EQ RADlAL FLOIY, AND SELF CLEANING. ^ � � O � i I— ' ' � ' RADIAL MEDJA DEPTH SHALL B£ 7–lNCHES. FILTER MEDIA CONTACT TlME SHALL BE AT L£AST 39 SECONDS. ` � Z � l8" lNLE7 18" 0lITLET i. S P E C I F I C F L O W R A T E 1 S E O U A L T O T H E F I L T E R T R E A T M F N 7 C A P A C 1 7 Y (gpm J D l N D E D B Y T y F F 1 L T E R C O N T A C T SL'�FA�� I� �D W — � � AREA (sq 1t). � � � � FLOW �\;L _ S;J_ o � ,� INSTALLA TION NOTES: ' � � � 7. ANY SUB–BASE, BACKFILL D£PT,'!, ti,^J� GR AId7!–FLOiA710PJ FR0�.4'SIG�VS AP,E SliE–SPECIrIC G��G�`i CGPJS,'U£,4A71C`:S 96" I.D. MANHOLE � STRIJCRJRE AND SHALL B£ SPEClFlEO BY ENGlNEER OF RECORD. 2. CONTRACTOR TO PROVIDE EQUIP�b1ENT WJTH SUFFIGEN7 LIF77NG AND REACH CAPACfTY TO LIFT AND SET 7HE STORMFILTER STRUCTURE (LIFANG C�UTCNES PRaV1DE0). (114) O.D. 3. CONTRACTOR TO INSTALL JDlNT SEALANT BE7WEEN ALL STRUCTURE SECTIONS AND ASSEMBLE STRUCTURE. 4. CONTRACTOR TO PROVIDE, INSTALL, AND GROUT INLET PIPE(S). 5. CONTRAC70R TO PR01/lDE AMD lNSTALL CONN£C70R TD THE OUTL£T RISER S7UB. STOh'MFILTER EOUIPPfD W'T'ri A TOP SLAB ACCESS DUAL DIAM£TER HOPE OU7LET STUB AND SAND COLLAR. !F OUTLET PlPE 1S LARGER TI-'AN 8 INCHfS, CONTRACTOR 70 ' SE£ FRAM£ AND COVfR REMDUE 7HE 8 1NCH OUTLET STUB AT MOLDED lN CUT LIN£. CDUPLING BY FERNCO OR EQUAL AND PROVIDED BY DETAIL CONTRACTOR. � 6. CONTF,ACTOR TD TAKE APPRO?RlATE McASJR£S TO PROTECT CA,4TRIDGES FROM CO1JS7i'UCT�ON–P,ELAT£D EROSION PLAN V/EW RUNCiF. ! STAND?.RD OJ7LET RISER � � �I FLOVSTIT• 43A STORMFIL TER DETAILS _`�C NTEC H• � D£SI ED BY: NAK ENGINEERED SOLlJT10N5 LLC PRAECT ENGINf£R: LRJ DATE: 01.29.?013 PRO,.£CT NO.: 12019 a:�,aars�,.��,.�saz91-'10.0.;� a�o�slc^;��^<,n DRAWlNC: 1 gs�, '�'�.'epw.' -;g_resl5ra�m�/er Jer�:�s��g 4��6/�L:7 �-J5:7]FN 7�i � CO'YRIG^T C�2C13, p,R. STRONG C��.SJLT`1G E"JGI�=EBS VC. SH££T.• � SECTION V CONVEYANCE SYSTEM ANALYSIS AND DESIGN Per C.R. #4 of the KCSWDM, the conveyance system must be analyzed and designed for existing tributary and developed onsite runoff from the proposed project. Pipe systems shall be designed to convey the 100-year design storm. The Rational Method will be used to calculate the Q-Ratio for each pipe node. A conveyance system consisting primarily of pipes and catch basins has been designed for the Project. Onsite runoff will be collected by multiple catch basins. Pipes are 12- II inch, 18-inch and 24-inch diameter LCPE (N-12) material. The peak flow rate calculated for the Site is 4.65 cfs theoretically occurring during the 100-year, 15-minute ' storm event. Per the following calculations, the most shallow-sloped pipe proposed in �, the conveyance system is capable of conveying a quantity greater than this flow. The � vault primary overflow riser is designed to convey the 100-year peak storm, based on � the KCRTS 15-minute time series for developed, undetained conditions on site. An 18- , inch riser and outfall pipe are provided from the vault to outFall splash pad located near the edge of existing wetland in Tract "B". DEVELOPED 15-MINUTE TIME STEP MODELING INPUT: ___ �}� _ - � =� i� Land tlse Sumrnary :�:��-��"``` ,�� -'��,��, ��,��„� ��• � :�'�`��. �.'� �-�� a: ,�re a ? Till Forest 0.00 acres Till Pas#ure U.00 acres � Till Grass 7.�1 acres Outwash Farest 0.00 acres � Outwrash Pasture 0.00 acres � Outw�sh Grass 0.00 acres ` Wetland 0.00 acres Impervious 3.17 acres ' � Total � '' � A.9$ acres � ,', � Scale Factor : 1.00 �5-Min Reduced � Edit Flaw Paths � ---- - - - — - - ` � Time Series: DEV-15MIN » ` Cnmpute Time Series � � _ _ __ � � � Modii}r User Input � � a � _ File for computed Time Series [.TSF] ;, ..r. � - .. - _�.�r�.._.�.. ��,��:�.>��. •_��. 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 30 of 43 Drainage Repo�t City of Renton DEVELOPED 15-MINUTE TIME STEP MODELING OUTPUT: Flow Frequency Analysis Time Series File:dev-15min.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 1. 51 6 8/27/O1 18:00 4 . 65 1 100.00 0. 990 1. 07 8 1/05/02 15:00 3.25 2 25.00 0. 960 3.25 2 12/08/02 17:15 2. 11 3 10.00 0. 900 1.21 7 8/23/04 14:30 1.86 4 5.00 0.800 1. 86 4 11/17/04 5:00 1.81 5 3.00 0. 667 1. 81 5 10/27/05 10:45 1.51 6 2.00 0.500 2. 11 3 10/25/06 22:45 1.21 7 1.30 0.231 4. 65 1 1/09/08 6:30 1.07 8 1. 10 0. 091 Computed Peaks 4 . 19 50.00 0. 980 � il FLOW CONTROL PRIMARY OVERFLOW Using standard orifice equation to determine stand pipe diameter in control structure Ref. KCSWDM '98 Figure 5.3.4.H i Q�oo = 100-Year, 24-Hour Peak Storm calculated using KCRTS Qioo = 1.88 cfs HM� = Maximum available head in feet measured from crest of weir i HM� = 0.5 ft. D = Riser Diameter D = �Q�oo / (3.782 * HM�.5"0.5 // i D = 0.84 ft. (min. diameter) round up to nearest standard pipe diameter use D = 18 in. or 1.5 ft. Calculate actual height above the weir expected during the 100-year, 60 Minute storm H = Actual head above weir achieved with Q��,= H = (Q�oo / (9.739 * D))^0.6� H = 0.25 ft. � ■ 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 32 of 43 Drainage Report City of Renton BIRD CAGE EMERGENCY OVERFLOW Using sharp crested weir equation to determine stand pipe diameter in control structure Ref. KCSWDM '09 Figure 5.3.4.E Q�oo= 100-Year Peak Storm calculated using KCRTS 15-Minute Time Steps Q�oo= 4.65 cfs P= Height of primary overflow above outlet invert elevation P= 14.25 ft. D= Control structure diameter D= 48 in. L= Control structure circumference L= 12.57 ft. C= 3.27+0.4H/P (ft) use... Qioo= 3.27+0.4H/P(L-0.2H)H^1.5 H= Emergency overFlow water ��rfa�e e'�evation H= 0.24 f' �.iJiiiiiicifi,. t'viiU 'vuiiaii i.'vliv�ydiit,c Solve For...... Full Flow Capacity Diameter.......................1.50 ft Velocity.........................8.97 fps Slope.............................0.0194 ft/ft Flow Area..................1.77 sf Manning's n...................0.012 Critical Slope ............0.0168 ft/ft Discharge......................15.85 cfs Critical Depth...........1.42 ft Depth.............................1.50 ft Percent Fu11..............100.00 % Froude Number............Full Full Capacity............15.85 cfs QMAX @.94D.............17.05 cfs Rock Protection at Outfall Per Table 4.2.2.A of the 2009 KCSWDM, a 12' long x 7.5' wide x 2' deep Riprap pad with a crown height of 1 foot will be required at design discharge velocity of 8.97 fps. 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 33 of 43 Drainage Report City of Renton BACKWATER ANALYSIS _2013 D. R STRONG Consulting Engineers Inc. Piper s Bluff Plat Page 34 of 43 Drainage Report City of Renton Path: c:\bw Storm Water Runoff Variables: A= Total of Subasin and Tributary Areas C= Runoff Coefficient(the anticipated proportion of rainfall volume that runs off the area)see'98 KCSWM Table 3.2.1A C�= Composite Runoff Coefficient C�= S(Cn`An)�Arota� T� Time of Concentration(Typically 6.3 minutes which is the minimum value used in calculations) R= design return frequency iR= Unit peak rainfall intensity factor �R= �aR)(T�)"�-bR) aR,bR= coefficients from'98 KCSWM Table 3.2.1.B used to adjust the equation for the design storm IR= Peak rainfall intensity factor for a storm of retum frequency'R' �R- PR �R PR= total precipitation(inches)for the 24-hour storm event for the given frequency. See Issopluvial Maps in'98 KCSWM Figures 3.2.1.A-D QR= peak flow(cfs)for a storm of return frequency'R' QR= CC;�R A The Q-Ratio describes the ratio of the tributary flow to the main upstream flow. , R= 100 -year storm aR= 2.61 I bR= 0.63 PR= 3.4 inches Conveyance System Variables: d= pipe diameter n= Manning's Number 1= Iength of pipe Pipe Structures Subasins E A A C C� T� iR IR QR SQR Q- d Material n I Slope invert invert over- Q V Bend CB Tributaries subasin Ratio in out flow Full Full Dia ........................................................................................................................................................................................................................................................................................................................................................................elev. Flow Flow .............................................................. ....-•---��FROM CB To CB...................................sf Ac..........................Ac Min.................................cfs cfs................................in..............................................ft...........%.............ft...............ft..............ft.............cfs............�s.......................... ........................ .................... .................... ................... CB#11A TO INLETI 11A 11A 11 11A 5446 0.13 0.57 6.3 0.82 2.78 0.20 0.20 0.00 12 N-12 0.012 16 1.00 460.D0 459.84 464.00 3.87 4.93 0 2 11 11 10 11 8630 0.20 0.65 6.3 0.82 2.78 0.36 0.56 1.81 12 N-12 0.012 231 2.00 459.84 455.22 464.00 5.47 6.97 90 2 FROM RUN 10A-10 21828 0.50 0.69 10 10 9A 10 24633 0.57 0.67 10 10 9A 10 46461 1.07 0.67 6.3 0.82 2.78 1.98 2.53 3.54 12 N-12 0.012 144 5.01 455.22 448.00 459.38 8.67 11.03 0 2 9A 9A 9 9A 16790 0.39 0.64 6.3 0.82 2.78 0.69 3.22 0.27 12 N-12 0.012 16 1.00 448.00 447.84 452.00 3.87 4.93 21 2 9 9 8 9 15717 0.36 0.64 6.3 0.82 2.78 0.65 3.87 0.20 12 N-12 0.012 75 12.99 447.84 438.10 452.00 13.95 17.76 42 2 8 8 7 8 1726 0.04 0.90 6.3 0.82 2.78 0.10 3.97 0.03 12 N-12 0.012 39 10.08 438.10 434.17 443.26 12.29 15.64 21 2 7 7 6 7 859 0.02 0.90 6.3 0.82 2.78 0.05 4.02 0.01 12 N-12 0.012 99 11.28 434.17 423.00 438.17 13.00 16.55 0 4 FROM RUN 6A-6 5581 0.13 0.90 6 6 1A 6 2201 0.05 0.90 6 6 1A 6 7782 0.18 0.90 6.3 0.82 2.78 0.45 4.47 0.11 18 N-12 0.012 41 5.41 423.00 420.78 427.16 26.55 15.02 0 2 FROM RUN 5•1A 67058 1.54 0.71 1A 1A 1 1A 2671 0.06 0.90 1A 1A 1 1A 69729 1.60 0.90 6.3 0.82 2.78 4.01 8.48 0.90 12 N-12 0.012 18 1.00 420.78 420.60 424.78 3.87 4.93 0 2 1 1 VAULT IN 1 1 4416 0.10 0.68 6.3 0.82 2.78 0.19 0.19 0.02 12 N-12 0.012 143 1.33 420.60 418.70 424.82 4.46 5.68 39 2 74145 1.70 1.92 CB#5 TO CB#1A 5 5 4 5 6994 0.16 0.90 6.3 0.82 2.78 0.40 0.40 0.00 12 N-12 0.012 235 3.42 448.84 440.80 452.84 7.16 9.11 0 2 4 4 3 4 29650 0.68 0.68 7.3 0.75 2.54 1.18 1.18 1.00 12 N-12 0.012 131 11.13 440.80 426.22 444.80 12.91 16.44 91 4 FROM RUN 13-3 11028 0.25 1.15 3 3 2 3 18135 0.42 0.69 3 3 2 3 29163 0.67 0.69 8.3 0.69 2.34 1.07 1.07 2.00 12 N-12 0.012 37 7.81 426.22 423.33 432.05 10.82 13.77 92 4 2 2 1A 2 1251 0.03 0.90 9.3 0.64 2.18 0.06 0.06 3.00 12 N-12 0.012 41 6.22 423.33 420.78 427.33 9.65 12.29 93 2 67058 1.54 0.71 CB#13 TO CB#3 13 13 12 13 3473 0.08 0.90 6.3 0.82 2.78 0.20 0.20 0.00 12 N-12 0.012 162 4.35 445.79 438.75 449.79 8.07 10.27 90 2 12 12 3 12 7555 0.17 0.74 8.3 0.69 2.34 0.30 0.30 2.00 12 N-12 0.012 103 12.17 438.75 426.22 442.75 13.50 17.19 92 2 11028 0.25 1.15 Pipe Structures Subasins E A A C Cc T� iR IR Qa SQR Q- d Material n I Slope invert invert over- Q V Bend CB Tributaries subasin Ratio in out flow Full Full Dia elev. Flow Flow ............................................................................................................................................................................................................................................................................................................................................................................................................................................... ...........FROM CB To CB...................................Sf............A�..........................Ac Min.................................cfs cfs................................!n..............................................ft...........%.............ft...............ft............._ft.............cfs............fPs.......................... ............................... ................... ................... CB#10A TO CB#10 10A 10A 10 10A 21828 0.50 0.69 6.3 0.82 2.78 0.96 0.96 0.00 12 N-12 0.012 16 1.00 455.38 455.22 459.38 3.87 4.93 0 2 CB#6A TO CB#6 6A 6A 6 6A 5581 0.13 0.90 6.3 0.82 2.78 0.32 0.32 0.00 12 N-12 0.012 16 1.00 423.16 423.00 427.16 3.87 4.93 0 2 CB#19 TO VAULT IN 2 19 19 VAULT IN 2 19 16725 0.38 0.58 6.3 0.82 2.78 0.62 0.62 0.00 12 N-12 0.012 63 31.65 441.94 422.00 441.94 21.77 27.72 0 2 16725 0.38 0.58 EX CB TO SD OTFALL X CE EX CB 18 EX CB 0 0.00 0.00 6.3 0.82 2.78 0.00 0.00 0.00 12 N-12 0.012 12 6.50 465.11 464.33 467.94 9.87 12.56 0 2 18 18 17 18 0 0.00 0.00 6.3 0.82 2.78 0.00 0.00 0.00 12 N-12 0.012 49 3.71 464.33 462.51 467.33 7.46 9.50 90 2 17 17 16 17 0 0.00 0.00 6.3 0.82 2.78 0.00 0.00 0.00 12 N-12 0.012 299 3.96 462.51 450.67 466.51 7.70 9.81 90 2 16 16 iD OUTFALI 16 0 0.00 0.00 6.3 0.82 2.78 0.00 0.00 0.00 12 N-12 0.012 19 0.53 450.67 450.57 453.38 2.81 3.57 90 2 0 0.00 0.00 BACKWATER COMPUTER PROG:�AM FOR PIPES Pipe data from file:CB#11A TO INLETl.bwp Surcharge condition at intermediate junctions Tailwater Elevation:422.72 feet i, Discharge Range:0.5 to 10. Sfi=^ �= � .� 'c`Gl Overflow Elevation:964. fee- � Weir:NONE �� Upstream Velocity:0. feet/se� �� PIPE NO. 1: 147 LF - 24"CP @ 1.12o OUTLET: 418.?�=� -`7=L�: <_� . �_ --."_"-P: �. JLTNC NO. 1: OVERFL04�-EL: 424.82 BEND: 39 DEG DIE:i?^71�i'I=: 4.0 �-��':1I0: U. :J� Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HTv- **��**�**********�*��*�***�*�*+*��*��*�**************�**�*�**��***�****�***,.+ ill * 0.50 3.09 422.73 0.012 0.25 0.20 4.72 4.72 3.09 3.09 0.3`_ 1.00 3.08 422.72 * 0.012 0.35 0.27 4.72 4.72 3.08 3.08 0.45 1.50 3.09 422.73 * 0.012 0.43 0.33 4.72 4.72 3.09 3.08 0.50' 2.00 3.09 422.73 * 0.012 0.50 0.38 4.72 4.72 3.09 3.09 0. 6= 2.50 3.10 422.74 * 0.012 0.56 0.42 4.72 4.72 3.10 3.09 O.i2 3.00 3.10 422.74 * 0.012 0.61 0.46 4.72 4.72 3.10 3.09 0.7: 3.50 3.11 422.75 * 0.012 0.66 0.50 4.72 4.72 3.11 3.10 0.�5 4.00 3.12 �22.76 * 0.012 0.71 0.54 4.72 4.72 3.12 3.11 0. 91 9.50 3.13 422.77 * 0.012 0.75 0.57 9.72 4.72 3.13 3.11 0. 97 5.00 3.14 422.78 * 0.012 0.79 0.60 4.72 4.72 3.14 3.12 1.02 5.50 3.15 422.79 * 0.012 0.83 0.63 4.72 4.72 3.15 3.13 1.06 6.00 3.17 422.81 * 0.012 0.87 0.66 4.72 4.72 3.17 3.14 1.10 6.50 3.18 422.82 * 0.012 0.91 0.69 4.72 4.72 3.18 3.15 1.15 -.00 3.20 422.84 * 0.012 0.94 0.72 4.72 4.72 3.20 3.16 1.18 �.50 3.22 422.86 * 0.012 0.98 0.74 4.72 4.72 3.22 3.17 1.22 8.00 3.24 422.88 * 0.012 1.01 0.77 4.72 4.72 3.24 3.18 1.2� 8.50 3.26 422.90 * 0.012 1.04 0.79 4.72 4.72 3.26 3.20 1.28 9.00 3.28 422.92 * 0.012 1.08 0.82 4.72 4.72 3.28 3.21 1.31 9.50 3.30 422.94 * 0.012 1.11 0.84 4.72 4.72 3.30 3.23 1.34 10.00 3.32 422.96 * 0.012 1.14 0.87 4.72 4.72 3.32 3.24 1.36 PIPE N0. 2: 18 LF - 18"CP @ 2.00s OUTLET: 419.64 INLET: 420.00 INTYP: 5 JUNC NO. 2: OVERFLOW-EL: 424.78 BEND: 0 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.90 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ��x��*x************�*****+*****************�***�*********************�*�******* G.49 2.74 422.74 * 0.012 0.26 0.18 3.09 3.09 2.74 2.74 0.33 G.gg 2.73 422.73 * 0.012 0.37 0.26 3.08 3.08 2.72 2.73 0.48 1.47 2.74 422.74 * 0.012 0.46 0.31 3.09 3.09 2.73 2.74 0.60 1.96 2.75 922.75 * 0.012 0.53 0.36 3.09 3.09 2.74 2.75 0.71 2.44 2.77 422.77 * 0.012 0.60 0.40 3.10 3.10 2.74 2.77 0.80 2.93 2.79 422.79 * 0.012 0.66 0.44 3.10 3.10 2.75 2.79 0.88 3.42 2.82 422.82 * 0.012 0.71 0.47 3.11 3.11 2.77 2.82 0.96 �.91 2.84 422.84 * 0.012 0.76 0.51 3.12 3.12 2.78 2.84 1.04 4.40 2.88 422.88 * 0.012 0.81 0.54 3.13 3.13 2.80 2.88 1.11 4.89 2.92 422.92 * 0.012 0.86 0.57 3.14 3.14 2.81 2.92 1.18 5.38 2.96 422.96 * 0.012 0.90 0.60 3.15 3.15 2.83 2.96 1.25 5.87 3.00 423.00 * 0.012 0.94 0.63 3.17 3.17 2.86 3.00 1.31 6.36 3.05 423.05 * 0.012 0.98 0.66 3.18 3.18 2.88 3.05 1.3E 6.84 3.10 423.10 * 0.012 1.02 0.69 3.20 3.20 2.91 3.10 1.44 7.33 3.16 423.16 * 0.012 1.05 0.72 3.22 3.22 2.93 3.16 1.51 �.82 3.22 423.22 * 0.012 1.09 0.74 3.24 3.24 2.96 3.22 1.57 8.31 3.28 423.28 * 0.012 1.12 0.77 3.26 3.26 2.99 3.28 1.64 8.80 3.35 423.35 * 0.012 1.15 0.80 3.28 3.28 3.03 3.35 1.72 9.29 3.42 423.42 * 0.012 1.18 0.82 3.30 3.30 3.06 3.42 1.81 9.78 3.50 423.50 * 0.012 1.21 0.85 3.32 3.32 3.10 3.50 1.G0 PIPE NO. 3: �1 Lr - 12"CP @ 7.32� OUTLET: 420.00 INLET: 423.00 INTYP: 5 JUNC NO. 3: OVERFLOW-EL: 427.16 BEND: 0 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.11 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI *****�*��**************************�**********��**��*��+�********************** 0.26 0.25 423.25 * 0.012 0.21 0.11 2.74 2.74 0.21 ***** 0.25 0.52 0.37 423.37 * 0.012 0.30 0.16 2.73 2.73 0.30 ***** 0.37 0.77 0.47 423.47 * 0.012 0.37 0.19 2.74 2.74 0.37 ***** 0.47 1.03 0.55 423.55 * 0.012 0.43 0.22 2.75 2.75 0.43 ***** 0.55 1.29 0.63 923.63 * 0.012 0.48 0.24 2.77 2.77 0.48 ***** 0.63 1.55 0.70 423.70 * 0.012 0.53 0.27 2.79 2.79 0.53 ***** 0.70 1.80 0.76 423.76 * 0.012 0.58 0.29 2.82 2.82 0.58 ***** 0.76 2.06 0.83 423.83 * 0.012 0.62 0.31 2.84 2.84 0.62 ***** 0.83 2.32 0.89 423.89 * 0.012 0.66 0.33 2.88 2.88 0.66 ***** 0.89 2.58 0.95 423.95 * 0.012 0.69 0.34 2.92 2.92 0.69 ***** 0.95 2.83 1.01 424.01 * 0.012 0.73 0.36 2.96 2.96 0.73 ***** 1.01 3.09 1.07 429.07 * 0.012 0.76 0.38 3.00 3.00 0.76 ***** 1.07 3.35 1.15 424.15 * 0.012 0.79 0.39 3.05 3.05 0.79 ***** 1.15 3.61 1.24 424.24 * 0.012 0.82 0.41 3.10 3.10 0.82 ***** 1.24 3.86 1.33 424.33 * 0.012 0.84 0.43 3.16 3.16 0.84 ***** 1.33 4.12 1.42 424.42 * 0.012 0.86 0.44 3.22 3.22 0.86 ***** 1.42 4.38 1.52 424.52 * 0.012 0.88 0.46 3.28 3.28 0.88 ***** 1.52 4.64 1.63 424.63 * 0.012 0.90 0.47 3.35 3.35 0.90 ***** 1.63 4.89 1.74 424.74 * 0.012 0.92 0.49 3.42 3.92 0.92 ***** 1.74 5.15 1.86 424.86 * 0.012 0.93 0.50 3.50 3.50 0:93 ***** 1.86 PIPE NO. 4: 99 LF - 12"CP @ 11.28� OUTLET: 423.00 INLET: 434.17 INTYP: 5 JUNC NO. 4: OVERFLOW-EL: 438.17 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.01 i Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI I ***********�*****�*+�*�*************�************+*�***�**********************� 0.23 0.21 434.38 * 0.012 0.20 0.10 0.25 0.25 0.20 ***** 0.21 0.46 0.33 434.50 * 0.012 0.29 0.13 0.37 0.37 0.29 ***** 0.33 0.70 0.42 434.59 * 0.012 0.35 0.16 0.47 0.47 0.35 ***** 0.42 0.93 0.49 434.b6 * 0.012 0.41 0.19 0.55 0.55 0.41 ***** 0.49 1.16 0.56 434.73 * 0.012 0.46 0.21 0.63 0.63 0.46 ***** 0.56 1.39 0.62 434.79 * 0.012 0.50 0.23 0.70 0.70 0.50 ***** 0.62 1.62 0.68 434.85 * 0.012 0.55 0.24 0.76 0.76 0.55 ***** 0.68 1.85 0.74 434.91 * 0.012 0.59 0.26 0.83 0.83 0.59 ***** 0.74 2.09 0.79 434.96 * 0.012 0.62 0.28 0.89 0.89 0.62 ***** 0.79 2.32 0.84 435.01 * 0.012 0.66 0.29 0.95 0.95 0.66 ***** 0.84 2.55 0.88 435.05 * 0.012 0.69 0.31 1.01 1.01 0.69 ***** 0.88 2.78 0.93 435.10 * 0.012 0.72 0.32 1.07 1.07 0.72 ***** 0.93 3.01 0.98 435.15 * 0.012 0.75 0.33 1.15 1.15 0.75 ***** 0.98 3.25 1.04 435.21 * 0.012 0.78 0.35 1.24 1.24 0.78 ***** 1.04 3.48 1.11 435.28 * 0.012 0.80 0.36 1.33 1.33 0.80 ***** 1.11 3.71 1.17 435.34 * 0.012 0.83 0.37 1.42 1.42 0.83 ***** 1.17 3.94 1.25 435.42 * 0.012 0.85 0.38 1.52 1.52 0.85 ***x* 1.25 4.17 1.32 435.49 * 0.012 0.87 0.40 1.63 1.63 0.87 ***** 1.32 4.40 1.40 435.57 * 0.012 0.88 0.41 1.74 1.74 0.88 ***** 1.40 4.64 1.49 435.66 * 0.012 0.90 0.92 1.86 1.86 0.90 ***** 1.49 PIPE NO. 5: 39 LF - 12"CP @ 10.08g OUTLET: 434.17 INLET: 438.10 INTYP: 5 • JUNC NO. 5: OVERFLOW-EL: 443.26 BEND: 21 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.03 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ****�*�****+*�************�**+**�*�*�*�***�****�***�**************************� 0.23 0.21 438.31 * 0_012 0.20 0_10 0.21 0.21 0.20 ***** 0.21 0.46 0.33 438.43 * 0.012 0.29 0.14 0.33 0.33 0.29 ***** 0.33 0.69 0.42 438.52 * 0.012 0.35 0.17 0.42 0.42 0.35 ***** 0.42 0.92 0.50 438.60 * 0.012 0.41 0.19 0.49 0.49 0.41 ***** 0.50 1.14 0.57 438.67 * 0.012 0.46 0.21 0.56 0.56 0.46 ***** 0.57 1.37 0.63 438.73 * O.a12 0.50 0.23 0.62 0.62 0.50 ***** 0.63 1.60 0.69 438.79 * 0.012 0.54 0.25 0.68 0.68 0.54 ***** 0.69 1.83 0.75 438.85 * 0.012 0.58 0.27 0.74 0.74 0.58 ***** 0.75 2.06 0.80 438.90 * 0.012 0.62 0.28 0.79 0.79 0.62 ***** 0.80 2.29 0.85 438.95 * 0.012 0.65 0.30 0.84 0.84 0.65 ***** 0.85 2.52 0.91 439.01 * 0.012 0.69 0.31 0.88 0.88 0.69 ***** 0.91 2.75 0.95 439.05 * 0.012 0.72 0.33 0.93 0.93 0.72 ***** 0.95 2. 98 1.01 439.11 * 0.012 0.74 0.34 0.98 0.98 0.74 ***** 1.01 3.21 1.07 439.17 * 0.012 0.77 0.35 1.04 1.04 0.77 ***** 1.07 3.43 1.14 439.24 * 0.012 0.80 0.37 1.11 1.11 0.80 ***** 1.14 3.66 1.21 439.31 * 0.012 0.82 0.38 1.17 1.17 0.82 ***** 1.21 3.89 1.29 439.39 * 0.012 0.84 0.39 1.25 1.25 0.84 ***** 1.29 4.12 1.37 439.47 * 0.012 0.86 0.40 1.32 1.32 0.86 ***** 1.37 4.35 1.45 439.55 * 0.012 0.88 0.92 1.40 1.40 0.88 ***** 1.45 4.58 1.54 439.64 * 0.012 0.90 0.43 1.49 1.99 0.90 ***** 1.54 PIPE NO. 6: 75 LF - 12"CP @ 12.99� OUTLET: 438.10 INLET: 447.84 INTYP: 5 JUNC NO. 6: OVERFLOW-EL: 452.00 BEND: 42 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.20 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI *****�******�*�*�*************�***�*��**�****��**�****�***********�*�********** 0.22 0.20 448.04 * 0.012 0.20 0.09 0.21 0.21 0.20 ***** 0.20 0.45 0.31 448.15 * 0.012 0.28 0.13 0.33 0.33 0.28 ***** 0.31 0.67 0.40 448.24 * 0.012 0.35 0.15 0.42 0.42 0.35 ***** 0.40 0.89 0.48 448.32 * 0.012 0.40 0.18 0.50 0.50 0.40 ***** 0.48 I 1.12 0.56 498.40 * 0.012 0.45 0.20 0.57 0.57 0.45 ***** 0.5� ! 1.34 0.63 448.47 * 0.012 0.49 0.21 0.63 0.63 0.49 ***** 0. �_ 1.56 0.70 448.54 * 0.012 0.54 0.23 0.69 0.69 0.54 ***** 0.� 1.79 0.76 448.60 * 0.012 0.57 0.25 0.75 0.75 0.57 ***** 0. � 2.01 0.82 448.66 * 0.012 0.61 0.26 0.80 0.80 0.61 ***** 0. - 2.23 0.89 448.73 * 0.012 0.64 0.28 0.85 0.85 0.64 ***** 0. 2.46 0.95 448.79 * 0.012 0.68 0.29 0.91 0.91 0.68 ***** 0. : 2.68 1.01 448.85 * 0.012 0.71 0.30 0.95 0.95 0.71 ***** 1. 2.90 1.07 448.91 * 0.012 0.74 0.31 1.01 1.01 0.74 ***** 1. 3.13 1.14 448.98 * 0.012 0.76 0.33 1.07 1.07 0.76 ***** 1.14 3.35 1.23 449.07 * 0.012 0.79 0.34 1.14 1.14 0.79 ***** 1.23 3.57 1.32 449.16 * 0.012 0.81 0.35 1.21 1.21 0.81 ***** 1.32 � 3.79 1.41 449.25 * 0.012 0.83 0.36 1.29 1.29 0.83 ***** 1.41 4.02 1.51 449.35 * 0.012 0.85 0.37 1.37 1.37 0.85 ***** 1.51 9.24 1.61 449.45 * 0.012 0.87 0.38 i.45 1.45 0.87 ***** 1.61 9.46 1.72 449.56 * 0.012 0.69 0.39 1.54 1.54 0.89 ***** 1.72 PIPE NO. 7: 16 LF - 12"CP @ 1.00o OUTLET: 447.89 INLET: 448.00 INTYP: 5 JUNC NO. 7: OVERFLOW-EL: 452.00 BEND: 21 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.27 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************�******�*********�*�****��**�*****�*�****** 0.19 0.23 448.23 * 0.012 0.18 0.15 0.20 0.20 0.18 ***** 0.23 0.37 0.34 448.34 * 0.012 0.26 0.21 0.31 0.31 0.26 ***** 0.34 0.56 0.42 498.42 * 0.012 0.32 0.26 0.40 0.40 0.32 ***** 0.42 0.74 0.49 448.49 * 0.012 0.37 0.30 0.48 0.48 0.37 ***** 0.49 0.93 0.56 448.56 * 0.012 0.41 0.34 0.56 0.56 0.41 ***** 0.56 1.12 0.62 448.62 * 0.012 0.45 0.37 0.63 0.63 0.45 ***** 0.62 1.30 0.67 448.67 * 0.012 0.99 0.41 0.70 0.70 0.49 ***** 0.67 1.49 0.79 448.79 * 0.012 0.52 0.44 0.76 0.76 0.57 0.79 0.73 1.67 0.84 948.89 * 0.012 0.55 0.47 0.82 0.82 0.65 0.84 0.78 1.86 0.90 448.90 * 0.012 0.59 0.49 0.89 0.89 0.72 0.90 0.83 2.04 0.97 948.97 * 0.012 0.62 0.52 0.95 0.95 0.80 0.97 0.89 2.23 1.05 949.05 * 0.012 0.64 0.55 1.01 1.01 0.89 1.05 0.94 2.42 1.14 949.14 * 0.012 0.67 0.58 1.07 1.07 0.98 1.19 0.99 2.60 1.24 949.24 * 0.012 0.70 0.61 1.14 1.14 1.06 1.29 1.04 2.79 1.37 449.37 * 0.012 0.72 0.63 1.23 1.23 1.15 1.37 1.09 2.97 1.49 449.49 * 0.012 0.74 0.66 1.32 1.32 1.25 1.49 1.14 3.16 1.63 449.63 * 0.012 0.77 0.69 1.41 1.41 1.36 1.63 1.20 3.35 1.77 449.77 * 0.012 0.79 0.72 1.51 1.51 1.47 1.77 1.27 3.53 1.92 449.92 * 0.012 0.81 0.76 1.61 1.61 1.58 1.92 1.34 3.72 2.08 450.08 * 0.012 0.83 0.79 1.72 1.72 1.71 2.08 1.4] PIPE NO. 8: 144 LF - 12"CP @ 5.01$ OUTLET: 448.00 INLET: 455.22 INTYP: � JUNC NO. 8: OVERFLOW-EL: 459.38 BEND: 0 DEG DIA/WIDTH: 2.0 Q-RATIO: 3.�4 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **��****�****�****�**�***�**�***************************�**********�*********** 0.15 0.19 455.41 * 0.012 0.16 0.10 0.23 0.23 0.16 ***** 0.19 0.29 0.28 455.50 * 0.012 0.23 0.13 0.34 0.34 0.23 ***** 0.28 0.44 0.35 955.57 * 0.012 0.28 0.16 0.42 0.42 0.28 ***** 0.35 0.58 0.41 455.63 * 0.012 0.32 0.18 0.49 0.49 0.32 ***** 0.4"_ 0.73 0.47 455.69 * 0.012 0.36 0.20 0.56 0.56 0.36 ***** 0.47 0.86 0.53 955.75 * 0.012 0.40 0.22 0.62 0.62 0.40 ***** 0.53 1.02 0.58 455.80 * 0.012 0.43 0.24 0.67 0.67 0.43 ***** 0.58 1.17 0.63 455.85 * 0.012 0.46 0.25 0.79 0.79 0.46 ***** 0.63 1.32 0.68 455.90 * 0.012 0.49 0.27 0.84 0.64 0.49 ***** 0.68 1.46 0.72 455.94 * 0.012 0.52 0.28 0.90 0.90 0.52 ***** 0.72 1.61 0.77 455.99 * 0.012 0.54 0.30 0.97 0.97 0.54 ***** 0.77 1.75 0.82 456.04 * 0.012 0.57 0.31 1.05 1.05 0.57 ***** 0.82 1. 90 0.86 456.08 * 0.012 0.59 0.32 1.19 1.14 0.59 ***** 0.86 2.G5 0.91 456.13 * 0.012 0.62 0.34 1.24 1.24 0.62 ***** 0.91 2.i9 0.96 456.18 * 0.012 0.64 0.35 1.37 1.37 0.64 ***** 0.96 2.34 1.00 456.22 * 0.012 0.66 0.36 1.49 1.49 0.66 ***** 1.00 2.�8 1.05 456.27 * 0.012 0.68 0.37 1.63 1.63 0.68 ***** 1.05 2.63 1.10 456.32 * 0.012 0.70 0.38 1.77 1.77 0.70 ***** 1.10 2.78 1.14 456.36 * 0.012 0.72 0.39 1.92 1.92 0.72 ***** 1.14 2. 92 1.20 456.42 * 0.012 0.74 0.41 2.08 2.08 0.74 ***** 1.20 PIP� NO. 9: 231 LF - 12"CP @ 2.00$ OUTLET: 455.22 INLET: 459.84 INTYP: 5 I JJNC N0. 9: OVERFLOW-EL: 464.00 BEND: 90 DEG DIA/WIDTH: 2.0 Q-RATIO: 1.81 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI �++x+x********�*�**++*********+**�********************************************* ��.03 0.09 459.93 * 0.012 0.08 0.06 0.19 0.19 0.08 ***** 0.09 ��.06 0.13 459.97 * 0.012 0.11 0.08 0.28 0.28 0.11 ***** 0.13 ��.10 0.16 460.00 * 0.012 0.13 0.10 0.35 0.35 0.13 ***** 0.16 ��. 13 0.19 460.03 * 0.012 0.15 0.11 0.41 0.41 0.15 ***** 0.19 0.16 0.21 460.05 * 0.012 0.17 0.12 0.47 0.47 0.17 ***** 0.21 ��.19 0.23 460.07 * 0.012 0.19 0.13 0.53 0.53 0.19 ***** 0.23 G.23 0.25 460.09 * 0.012 0.20 0.14 0.58 0.58 0.20 ***** 0.25 G.26 0.27 460.11 * 0.012 0.21 0.15 0.63 0.63 0.21 ***** 0.27 G.29 0.29 960.13 * 0.012 0.23 0.16 0.68 0.68 0.23 ***** 0.29 _�.32 0.31 460.15 * 0.012 0.24 0.17 0.72 0.72 0.24 ***** 0.31 0.35 0.33 460.17 * 0.012 0.25 0.18 0.77 0.77 0.25 ***** 0.33 G.39 0.34 960.18 * 0.012 0.26 0.19 0.82 0.82 0.26 ***** 0.34 0.42 0.36 460.20 * 0.012 0.27 0.19 0.86 0.86 0.27 ***** 0.36 G.45 0.37 460.21 * 0.012 0.28 0.20 0.91 0.91 0.28 ***** 0.37 G.48 0.39 460.23 * 0.012 0.29 0.21 0.96 0.96 0.29 ***** 0.39 0.51 0.40 460.24 * 0.012 0.30 0.21 1.00 1.00 0.30 ***** 0.40 G.55 0.41 460.25 * 0.012 0.31 0.22 1.05 1.05 0.31 ***** 0.91 0.58 0.43 460.27 * 0.012 0.32 0.23 1.10 1.10 0.32 ***** 0.43 0.61 0.44 460.28 * 0.012 0.33 0.23 1.14 1.14 0.33 ***** 0.94 G.59 0.45 460.29 * 0.012 0.34 0.24 1.20 1.20 0.34 ***** 0.45 F=?E NO.10: 16 LF - 12"CP @ 1.00$ OUTLET: 459.84 INLET: 460.00 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI x*��+�+**�****�*�*************�********************�***��*�****��************** r�.01 0.05 460.05 * 0.012 0.05 0.04 0.09 0.09 0.05 ***** 0.05 0.02 0.08 460.08 * 0.012 0.07 0.06 0.13 0.13 0.07 ***** 0.08 0.03 0.10 460.10 * 0.012 0.08 0.07 0.16 0.16 0.08 ***** 0.10 0.05 0.11 460.11 * 0.012 0.09 0.08 0.19 0.19 0.09 ***** 0.11 0.06 0.13 46G.?3 * 0.012 0.10 0.09 0.21 0.21 0.10 ***** 0.13 0.07 0.14 460.14 * 0.012 0.11 0.10 0.23 0.23 0.11 ***** 0.14 0.06 0.15 460.15 * 0.012 0.12 0.10 0.25 0.25 0.12 ***** 0.15 0.09 0.16 460.16 * 0.012 0.13 0.11 0.27 0.27 0.13 ***** 0.16 0.10 0.17 460.17 * 0.012 0.14 0.12 0.29 0.29 0.14 ***** 0.17 0.11 0.21 460.21 * 0.012 0.14 0.12 0.31 0.31 0.15 0.21 0.18 0.13 0.22 460.22 * 0.012 0.15 0.13 0.33 0.33 0.17 0.22 0.19 i 0.19 0.23 460.23 * 0.012 0.16 0.13 0.34 0.34 0.18 0.23 0.20 0.15 0.24 460.24 * 0.012 0.16 0.14 0.36 0.36 0.20 0.24 0.21 0.16 0.25 460.25 * 0.012 0.17 0.14 0.37 0.37 0.21 0.25 0.22 0.17 0.26 460.26 * 0.012 0.17 0.15 0.39 0.39 0.22 0.26 0.22 0.18 0.28 460.28 * 0.012 0.18 0.15 0.40 0.40 0.24 0.28 0.23 i 0.19 0.29 460.29 * 0.012 0.19 0.16 0.41 0.41 0.25 0.29 0.24 � 0.21 0.30 460.30 * 0.012 0.19 0.16 0.43 0.43 0.27 0.30 0.25 ' 0.22 0.31 460.31 * 0.012 0.20 0.17 0.44 0.44 0.28 0.31 0.25 �I 0.23 0.32 460.32 * 0.012 0.20 0.17 0.45 0.45 0.29 0.32 0.26 i , i-, � � 1 �__� i �I ; � _ i i -� I � __� II I BACKWATER COMPUTER PROGRF.M FG� PIPES Pipe data from file:CB#5 TO CB�1A.b��p Surcharge condition at intermediate junctions Tailwater Elevation:423.35 feet Discharge Range:0.5 to 5. Step of 0.� [cfs] Overflow Elevation:452.84 feet Weir:NONE Opstream Velocity:0. feet/se� PIPE NO. 1: 41 LF - 12"CP @ 8.12s OUTLET: 420.00 INLET: 423.33 IN1YP: 5 JUNC N0. 1: OVERFLOW-EL: 427.33 BEND: 90 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.02 Q(CFS) HW(FT) HW ELEV. * N-rAC DC DN TW DO DE HWO HWI **��**********�*�*****��*�*��************�*�*****�***********�**�******�***�* 0.50 0.36 423.69 * 0.012 0.30 0.15 3.35 3.35 0.30 ***** 0.36 1.00 0.56 423.89 * 0.012 0.43 0.21 3.35 3.35 0.43 ***** 0.56 1.50 0.74 424.07 * 0.012 0.52 0.25 3.35 3.35 0.52 ***** 0.74 2.00 0.91 424.24 * 0.012 0.61 0.29 3.35 3.35 0.61 ***** 0. 91 2.50 1.09 424.42 * 0.012 0.68 0.33 3.35 3.35 0.68 ***** 1.09 3.00 1.28 424.61 * 0.012 0.75 0.36 3.35 3.35 0.75 ***** 1.28 3.50 1.52 424.85 � 0.012 0.80 0.39 3.35 3.35 0.80 ***** 1.52 �.00 1.79 425.12 * 0.012 0.85 0.42 3.35 3.35 0.85 ***** 1.79 �.50 2.10 425.43 * 0.012 0.89 0.45 3.35 3.35 0.89 ***** 2.10 5.G0 2.4� 425.�8 * O.Q12 0.92 0.�8 3.35 3.35 0.92 ***x* 2.�5 PIFE NO. 2: 37 �F - 12"�P ? �.8-_`o CJ^LET: 423.33 _v'_E�: �26.22 INTY�: 5 I JUNC NO. 2: OVERFLOW-EL: 432.05 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.68 � Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI x��x*******�*********�****��***�+��**�*�**�**�***************�**�******�***** 0.49 0.36 426.58 * 0.012 0.30 0.15 0.36 0.36 0.30 ***** 0.36 0.98 0.55 426.77 * 0.012 0.42 0.21 0.56 0.56 0.42 ***** 0.55 1.97 0.73 426.95 * 0.012 0.52 0.25 0.74 0.74 0.52 ***** 0.73 1.96 0.89 427.11 * 0.012 0.60 0.29 0.91 0.91 0.60 ***** 0.89 2.45 1.06 427.28 * 0.012 0.68 0.33 1.09 1.09 0.68 ***** 1.06 2.94 1.24 427.46 * 0.012 0.74 0.36 1.28 1.28 0.74 ***** 1.24 3.43 1.47 427.69 * O.Oi2 0.80 0.39 1.52 1.52 0.80 ***** 1.47 3.92 1.72 427.94 * 0.012 0.85 0.42 1.79 1.79 0.85 ***** 1.72 4.41 2.01 428.23 * O.Oi2 0.89 0.45 2.10 2.10 0.89 ***** 2.01 4.90 2.39 42�.56 * 0.0"_2 G. 92 0.48 2.45 2.45 0.92 �**** 2.34 PIPE N0. 3: 131 L� - 12"CP @ 11.13� OUTLET: 4�6.22 INLET: 440.80 InTYP: 5 JJNC N0. 3: OVERFLOW-EL: 444.80 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 2.93 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI �x�x�+**********�**********��**�*****�**�**�*�***�***�***********�********�**** 0.29 0.25 441.05 * 0.012 0.23 0.11 0.36 0.36 0.23 ***** 0.25 0.58 0.38 441.18 * 0.012 0.32 0.15 0.55 0.55 0.32 ***** 0.38 G.87 0.50 441.30 * 0.012 0.90 0.18 0.73 0.73 0.40 ***** 0.50 "�.17 0.60 441.40 * 0.012 0.46 0.21 0.89 0.89 0.46 ***** 0.60 1.46 0.70 441.50 * 0.012 0.52 0.23 1.06 1.06 0.52 ***** 0.70 1.75 0.79 441.59 * 0.012 0.57 0.25 1.24 1.24 0.57 ***** 0.79 2.04 0.89 441.69 * 0.012 0.61 0.27 1.47 1.47 0.61 ***** 0.89 2.33 0.98 441.78 * 0.012 0.66 0.29 1.72 1.72 0.66 ***** 0.98 2.62 1.08 441.88 * 0.012 0.70 0.31 2.01 2.01 0.70 ***** 1.08 2.92 1.18 441.98 * O.Q12 0.74 0.33 2.39 2.34 0.74 ***** 1.18 PIPE NO. 4: 235 LF - 12"CP @ 3.42$ OUTLET: 440.80 INLET: 448.64 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **************��**�+***�*****************+***�*��*�*��**+�*�*�**********�***** 0.07 0.13 448.97 * 0.012 0.12 0.08 0.25 0.25 0.12 ***** 0.13 0.15 0.20 449.04 * 0.012 0.16 0.10 0.38 0.38 0.16 ***** 0.20 0.22 0.25 449.09 * 0.012 0.20 0.13 0.50 0.50 0.20 ***** 0.25 0.30 0.29 449.13 * 0.012 0.23 0.14 0.60 0.60 0.23 ***** 0.29 0.37 0.33 449.17 * 0.012 0.26 0.16 0.70 0.70 0.26 ***** 0.33 0.45 0.36 449.20 * 0.012 0.28 0.17 0.79 0.79 0.28 ***** 0.36 0.52 0.39 449.23 * 0.012 0.30 0.19 0.89 0.89 0.30 ***** 0.39 i 0.59 0.43 449.27 * 0.012 0.33 0.20 0.98 0.96 0.33 ***** 0.43 0.67 0.46 449.30 * 0.012 0.35 0.21 1.08 1.06 0.35 ***** 0.46 � 0.74 0.48 449.32 * 0.012 0.36 0.22 1.16 1.18 0.36 ***** 0.48 I , '� I I � BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:CB#13 TO CB#3.bwp Surcharge condition at intermediate junctions Tailwater Elevation:432.05 feet Discharge Range:0.5 to 3. Step of 0.5 [cfs] Overflow Elevation:449.79 feet Weir:NONE Upstream Velocity:0. feet/sec PIPE NO. 1: 103 LF - 12"CP @ 12.17$ OUTLET: 426.22 INLET: 438.75 INTYP: 5 JUNC NO. 1: OVERFLOW-EL: 442.75 BEND: 90 DEG DIA/WIDTH: 2.0 Q-RATIO: 1.50 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI - ****�*�***�**�*************�******�*�*�*+****�*�**�****�*�****�****�*********** 0.50 0.34 439.09 * 0.012 0.30 0.14 5.83 5.83 0.30 ***** 0.34 1.00 0.54 439.29 * 0.012 0.43 0.19 5.83 5.83 0.43 ***** 0.54 1.50 0.71 439.46 * 0.012 0.52 0.23 5.83 5.83 0.52 ***** 0.71 --• 2.00 0.68 439.63 * 0.012 0.61 0.27 5.83 5.83 0.61 ***** 0.88 2.50 1.04 439.79 * 0.012 0.68 0.30 5.83 5.83 0.66 ***** 1.04 � 3.00 1.22 439.97 * 0.012 0.75 0.33 5.83 5.83 0.75 ***** 1.22 F=PE NO. 2: 162 LF - 12"CP @ 4.35g OUTLET: 438.75 INLET: 445.79 INTYP: 5 � Q;CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **��***�**�********�**+�**+*�********��*�************************+***�********* 0.20 0.23 446.02 * 0.012 0.19 0.11 0.34 0.34 0.19 ***** 0.23 �� 0.40 0.34 446.13 * 0.012 0.27 0.16 0.54 0.54 0.27 ***** 0.34 0.60 0.42 446.21 * 0.012 0.33 0.19 0.71 0.71 0.33 ***** 0.42 0.80 0.50 446.29 * 0.012 0.36 0.22 0.88 0.88 0.38 ***** 0.50 1.00 0.5� 446.36 * 0.012 0.43 0.24 1.04 1.04 0.43 ***** 0.57 1.20 0.6� 44C.43 * 0.��12 0.4? �.�? '_.22 1.22 0.47 �**** O.o4 � � I. �, r - r � i � ' + i � BACfCti9ATER COMPUTER PRO�RAh1 F03 PIPES Pipe data from file:CB#6A TO CB #6.bwp Surcharge condition at intermediate junctions ' Tailwater Elevation:424.63 feet Discharge Range:0.5 to 3. Step of 0.5 [cfs] Overflow Elevation:427.16 feet Weir:NONE lipstream Velocity:0. feet/sec P=FE N0. 1: 16 LF - 12"CP @ 1.00% OUTLET: 423.00 INLET: 423.16 INTYP: 5 Q;CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ,�_�******�*�*��**�*��*x�x****�****+****�*****�********�**�*******�*��+****� 0.50 1.49 424.65 * 0.012 0.30 0.25 1.63 1.63 1.46 1.49 0.40 1.00 1.52 424.68 * 0.012 0.43 0.35 1.63 1.63 1.48 1.52 0.59 1.50 1.58 424.74 * 0.012 0.52 0.44 1.63 1.63 1.49 1.58 0.76 2.00 1.66 424.82 * 0.012 0.61 0.52 1.63 1.63 1.51 1.66 0.92 2.50 1.77 424.93 * 0.012 0.68 0.59 1.63 1.63 1.54 1.77 1.07 3.00 '.91 425.07 * 0.012 0.75 0.67 1.63 1.63 1.5? 1. 91 1.24 � BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:CB#l0A TO CB #l0.bwp Surcharge condition at intermediate junctions Tailwater Elevation:456.32 feet Discharge Range:0.5 to 3. Step of 0.5 [cfs] Overflow Elevation:459.38 feet Weir:NONE Upstream Velocity:0. feet/sec PIPE NO. 1: 16 LF - 12"CP @ 1.00$ OUTLET: 455.22 INLET: 455.38 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **�*�**�**********��***********************��**�**�**�************�**�*��***�* 0.50 0.96 456.34 * 0.012 0.30 0.25 1.10 1.10 0.95 0.96 0.40 1.00 0.99 456.37 * 0.012 0.43 0.35 1.10 1.10 0.95 0.99 0.59 1.50 1.06 456.44 * 0.012 0.52 0.44 1.10 1.10 0.97 1.06 0.76 2.00 1.13 456.51 * 0.012 0.61 0.52 1.10 1.10 0.98 1.13 0.92 2.50 1.25 456.63 * 0.012 0.68 0.59 1.10 1.10 1.01 1.25 1.07 3.00 1.38 456.76 * 0.012 0.75 0.67 1.10 1.10 1.04 1.38 1.24 I i I � BACKWATER COMPUTER PROGRA� rOR PIPES Pipe data from file:CB#20 TO VAULT IN 2.bwp - Surcharge condition at intermediate junctions Tailwater Elevation:422.72 feet Discharge Range:0.5 to 3. Step o` C.5 [cfs] Overflow Elevation:441.94 feet Weir:NONE Upstream Ve1o�i�y:0. feet/sec PIPr, NO. 1: c3 L= - -iZ"CP Ca �c.89`s JU"LE'1': 422.OJ 1P."LE'1': �38.94 1N:'Y'Y: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI *****�*****��********************��*��*:**�*********��*******�****�******�**� 0.50 0.30 439.24 * 0.012 0.30 0.11 0.72 0.72 0.30 ***** 0.27 1.00 0.46 439.40 * 0.012 0.43 0.16 0.72 0.72 0.43 ***** 0.46 1.50 0.63 939.57 * 0.012 0.52 0.19 0.72 0.72 0.52 ***** 0. 63 2.00 0.79 939.73 * 0.012 0.61 0.22 0.72 0.72 0.61 ***** 0.79 2.50 0.95 439.89 * 0.012 0.68 0.24 0.72 0.72 0.68 ***** 0. 95 3.00 1.11 940.0� * 0.012 0.75 0.2� 0.72 0.�2 0.75 ***** 1.1"_ G , � � � 1 I II ' FIGURE 8 BACKWATER ANALYSIS MAP I ,:2013 D. R. STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 35 of 43 Drainage Report City of Renton z W �n�n,orttx W " � re ssas� ' ` p (g � �' I �.,_ �'_: � : ��'+ � �;� ..S7A 16 918J,B915ER �c 2 � N ; � -- - - --- 1 � - -- 118 .r. y o {y CB 17 i � � � .. ��•:_ :-:_�3:., i.; .A_�_ .-_.-'-.- ,n7 ^• _, . CB 1A G�'6 TWE 2 54�/ ` a6 � ,i '_. - . 1,3 �___.,__'�;� .., ., :-.� STA"33s16.96 9B .�' , r� ��: � .-G6� I � . - W/7HRU CUFB 1N:E7 P2] �"ON'�GL S7RU_ZRE) � - .. � � ;. ' . � _. ST�2Jf17.99. 1117 L - ;a ..•.-'1{.--;;,^, � '. - � . . . . I .. B!D1RECTOR y •, ' .. : ' � ,• .. - ---- ., ; ' CB 4 . , VANEG,^.RA c L 6 - SA'�;E*.7&�61,5�.83"R I � 2 � � � , � � .: .� _. . . . :- _-_ , _ ' ' i F n, �� .,. �' - .._ . � . a , . .� � STA�15+!J7J1S.i7L '. g,7 . SIA:IE+9263. 1012C . Ry��,�" , 0 . �; :-,- _.� �' e I � � �� - � . . . . � . - SiA.]7+81.66. 1I.17 L Ce 2 4 �� SANf 7 RYZ' -� � U ,. .:. . , ; . . _�.".:- ... , � A. q � � CB.1' iYPE 2'45'I ."�,- ,.:.'� � '�.I - -' _. _.._...-.. � - .._..__._ _ , . ,�•'� . 6+LIF7 STA11�k SFE '� �ST0�7NFH.:ER MANHQC£ I+4 STA f .... , , � ' .:-.{ _„ _ ,_ � : . _ __. , � J4.77 L -- S=NEP.L�IXJ�, � CB 22 3 � - /. .*. .- __ -�-� �� .-1 � . � .57A. 16 0476.6'063 R �� 5T?J3+64.27, 17 96 P= '.`^ �� ... '` .. ' . .---- � . _.- - --� � �,. 1 I PiAA'fQR'QETAlLS� �.SEE 5NfET Ci1.f(1R BETN�S r.:., . q � STA:�-,��8��9��-� r : �. - 7,874 S.F. FS _ ; --- - � -=_ _ - _ � ,l �� - :__ � � � -_- ,::. � ' . _ . W .,_ __.- .. . . - --_f r ' j , , _ . -= _ _ _ _•; - -- _- F�' 1;2.5� S 2,671 .F. :. �, �� " . ce� ..;� 4ao ` ,,,.� � Z o -�� - - - - - -- - - _ _,..-. - - - . - - .=' �`i . ,- .....' ..__ _- _. _. -_ ._.'_._".'-'.._ _ , ..�. ^ ..-: ��S . _ � II �NERCENCY.OVEP�OA' W 47"S. , ,- 1 , _-�. _ _ i „ . .-, _._. - -- -- - � - - -- - - - --- --- -- � : , _ _ - --_- ----_ - - - _ _ �� <� .;-_ --�- - - --_. - . - - - - � , ' . - STA ffi+48 i3.,7'Jl)� R� . � �' � � � � - - � � _ � �� - �- . - - - - - - � - � - �� . t _ P 1 �� , � � \\; : _ _ .� � _ t, _ _ ._ i... � y I , : -I I __ �- � � I � z9 � �g z8 � 3, 9B S.F. - �;,� -_ ::.: � 11 _ � I I I S�A:?+ 00 "JO P I SiA IHt� �.... _ � _ (TJTh � ' ' R.►1 N5.29 � �' ( i{ � I I I � �: � I fc�4I223 { t _ I!£�.�3)661.. � I _.. �Pi.�� . \FS..G70 � 36 93 � -"r ' . ._ `�' _ _ . I . ._ 4� �LM:F. .- . ' . , \ . � � .. .. . , � . � 11 .< < ..::i4? . '� _ : . ' ,..Z � � I I .3 I- I . 41 I ( 5 6 ' ' �7 ' . A � ` y�� -.f .. `I � =� « ..� _..-- �, : � � � , L4 , , , � � � , i � � � � � �3 � - , �� , . ! - , � -. 4'.,.. . I ' �.9 O / 1% I L- - = � � I 4 - � � L� I. I ' I ,: ,998 �:F. `� , 7RACT�B � �� ,��s sJ L - L J .�,� s,2so s.F '. � a 6 , ""q'' F - ' R5 _ . . TA 4[`r013_. CGi . � - iz L76+44.tE_817 i ' _ , .. �� Q :. � ' -^ �, 6,J93 S F - --� J �.-�.�� _ ` E°a�8�o' `. _ �� - ; . 3,�73 S. I � i �i� ° � . `� � � � , � � � ' � a �- 1 �� i, r . , �j �] l� uj ca en �er�ss aonD .. � . �.�� i '� .-'- _... .._... .:_I . I_ I PIJ � ��`.f \ L 1 L ',� � =I S;� 5r9A16./ . � , .. ._ . .__. . _ I �8. R `. . . - ' , I� � . '_ ✓I, ' , '- , ,.._.�.,.,._. f: � - -13,663 S.F. ' �i roun oi� er , ^ � � ,, , : I e � ,. . I � g . � ��' `�i[=,ro.00 '� . 4 .. �,�. _ .. : . i i I i � I(� \ P,F7PlNNG AALL . ,'�SEE 5'RUCTiIRFt i .�,'E.. :q;.'1: Yj i / �-� - -�-�,� � - I -'� . � j _ � � I L3 27 � � I� CB 7I \ ENG.4'EER/NG PL�hS' . � � � � � � _ - _ . -. ' '. �'12+70.08 J1.(XJ L 7/ l5±�6.77 8.17 L P .�J lhLE , . I 17 '.I I � � /� l ^- �� :�� '.. .,. . - �445�3 � � r- -.- . . \ 1£ . .. ' �� --....... " f - . • � ' � � ° _� � � � L � 1A � a _ � � � � i �e,�.o,�.�;�� .�� ' , , � �, � , ;: = , � :►L DA L ��FEWHtLIFTSTA71pY FQR PONGi � 53 � ,`- f �5,132 S F � � � j % ` � ' m�'��a w'^'-. ' � ' c:. , I !6 I ' �_ : �6,611 S.F. I � _� .F I � �6 xtm.ox : snc�c� r � I 8,30 R�� „A � .- . ,Z I � � � � ` 14 13 11 pT 4 �c _ ;..; R F0+7� d79,8/7�', I ,...o � : . :I4 I�.'O.'l.GO L. �. S�� ` ;., 314 SF . - I��I .. . �_'i L- _� ' � � �`. ;9a S.F W -'�I7�� .�� . l- - . ', j �.r• WL�PCN J��63.132CF. �'e_, , y .� \�I / • � _ _��: -� _ I I-- _ I.. � . I� ." ' �'S A-�1. . _S L� �� ' - n� T✓GA .� ,.- __-'_. :.-:-._- __�_ . - _ I . - . � . r S T 3,� ' ' _ �� 59 �TR,. ' .:i.. �_ , __._ ._ �- -�� -.- i.,'5 ;O.e � - - �� ' �L� , y . ... � . Uf�.�..,7 GEf e�� \ .., . i , . � . � _- 5T:72*]0.00.8.�7! � � - . . , _ . .�' �"�.-- ....s 5' -��. l� ... .. �, I.. . : . . . _ . . . ..y_ �-.� . . �. ' � �- ... :. . ._ O� '. .. . � _.,< . .',- '\ . , / ^ � . � � � � 4 ' _, _ ��T,� r ,j� : '�' ... . . '�. . -. _..__ _ ."_._ ,_...__..... .:. ��-{ ' - 4 r /--� ,,., �-,' : 5,21� S.F , I � �� . .: ,_ -/ 1 -_ , , �� .�.g c� . � �; , -- -.- ` � w z _; � �, Q 3,227 S.F. I , S.F 1.063 S.F. ` � � � � � , _ � - ...� , � } ..1- Pti .:. . , 4�� ' 5 A J0+79.11 77.H6 R ' � � .,,' � �� T,.. . .\ I.__. . . P10 u �. '., . .. __ ' . .- � m � � � • � Q 1 � STA:10+13.B8,27,17�A ... .. I � ; �� 1 - '� . . . . • � � , � . € ; I� � _ � _ � �, r � r ' Y �- -__� - -� _ - /�, � , 3 2 0 S.F. � . -- - - �:� � , � ��. � � Q --:---- • .. ,, - -1;: � , - . , - , � '- �`" 1 - _ - • /� �� •� � ` _ 1 � � Z u .;: r. � ` �� '' �--_.:.. ..,a�� - -� - - - � � T2qCT'�D' , Q OO , i e n ,,. . I I� � � � I �e Q . -„ 1 - .`% '�: 7A 70+,:9.79.8.I7 R 1�H td I I dT.KMfTL6E Y �'. . �: �.;f ..: �e.`.�P� :� �� _�.. �i '. " .., �1 � 7 I I I 57A:i r C�O.B.17R � � C99I _ ,..� � L910 . � . I �� f��iT �+�. '. ... _ \ m � � � J�-'.S.F _I'i.1 STA�14+13..96.9.I1 R '� 7A:50�E9.65,D.00 I �6�� 7�EP�R1/�71qy�RACr- � __ � � .. .... . _ .. - �I l�B I �� 9 �,1 '�. �Q 21 I I �. I .... . `, .. - � ', I �..,� . (SERI^,NG LO/S 4��R - (fl W � � ��=� � � � � � .�� z5 � � , L 9A ► 24 ` � 25 ` � � ��_ _ �� 172B 78, � ,. � � � ; -; . L5 574 S F.I ;i e•m F,c�m•,r� .1 I L 7� � � � ( � � I I PEk:ORA�fD STCRY 'S A�12r70�3 Ji 00 R '.' ` � i ' CB 18 � ' ' ORAihAGF Siu9!.T r�003 'S.F I I R 460.70 . 3 �� , I I .L�,9'.. ��•� � I ' 57A:30�4H.'2, 7.62 R � , � I ; M'N. 7R SLOPf W7 ! 557.20 I � �� '�oO �•�� t9q2 q+11.02 J(.OG I , � +� Y"- ,. - �- . .�.::.,-um " � _ - � � _ y ' ;.u,5z�e � I 1�.5,659 S.F. � . PROPOSFO S70RN G7A:NA�E �� .PP.OlSJ£7x6'MARKEP. - -?+ ��- _ J � _ _ J �44978 . .. I� � .. � '.,��y . „1 . . . . . , _. . .. ... ._ �. r . . . - � . - .. � I - SYSTFM ON HOCUTAN AIENJ.. .�. - - J _ . . ..J.. 2 :5.+.�� . < ; - - � � _ � L _ - J � �- � < , - . 70 CPNVEY EXISTMG G7A/NAG£ .-� ._' . ';�� ' �'. ` , - fROAI 5�!/7H _: . .. -_ ' . � . . � 1 .�': . , �- -_- ::. -... < ,/ . . . . ' .. . ... .. �, �' ' ...a. v-�' _- � .. '. . �.,._ . :' ..�. _ i .. ...�� .� � . _ ,. . .. . ' : '. ,. �L -, -. . , :� �- s i �! __ . . . . . � _ CB 19 . . _ �� I -_ - ' 57A:29+99.46. J7.78 P, � PI9A• .... . .. �. . . . - ' . , __ _ . _ ' . , . . , . . . - . .- ii F'"' ( � , � .. , _1 3 . : .,- - .. -' .._:'. _.�_: _,_. � . ... �.. �.' :�' .., , ' - I . _ _ I .. . - ._._ f ._,�.. I .�.. (P.EYO�£) ' :- . . ... ... .' _ _ �NFW 1'TO CB IS j , ,, �: _..�-�v .-._ . . . , .. - /f 4551r) ' i -� � I _ I ' , . -� -- T �--�- �� _ � . ... .. . . . . .. NORTH I DRAFTED BY.� NN( GRAPHIC SCALE ' DFS,�NEo B,, ,,,,�x O 3O 6O 9O PROJECT ENGI,NE£R: LRJ � � DaTE p&�i?p!? � '� PROJfCT NO.: 1Z029 1 INCH = 60FT. T.�'�7012'�0`��2079'�,J`,Lr�x�ngs`�P��.'s'�rr.y;,:e�..-y�,Rea�"%;qu�es'�L'7-38l.'5:�i13.Cwy^ 4/2E/2013 S:7?�2!P.V PG' FI('iU.RE: 8 -. ;..i�2'J�3 - JI _ - __T�1� -i . ��=Er'.� �.I'.�' _ 1 SECTION VI SPECIAL REPORTS AND STUDIES The following report and studies have been provided with this submittal. 1. Traffic Impact Analysis — Jake Traffic Engineering, Inc. July 30, 2012 2. Critical Areas Report & Supplemental Stream Study) — Sewall Wetland Consulting. April 15, 2013 3. Geotechnical Engineering Study — Terra Associates, Inc. .,August 9, 2012 and Addendum to Geotechnical Report dated February 1, 2013. 4. Structural Analysis and Design — Kosnik Engineering, PC. January 25th, 2013. 2013 D R STRCNG Corsul;irg Engineers Inc. Piper s 6!uff PIGt Page 36 of 43 Drainage Report City of Renton SECTION VII OTHER PERMITS, VARIANCES AND ADJUSTMENTS I 1. Structural retaining and rockery wall permit. � � � �- I ;- � ' � '�� , . � �.�_i ; ; ' i � I ; ` � 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 37 of 43 Drainage Report City of Renton SECTION VIII ESC PLAN ANALYSIS AND DESIGN (PART A) The Erosion and Sedimentation Control Design meets the nine minimum requirements: 1. Clearing Limits — Areas to remain undisturbed shall be delineated with a high- visibility plastic fence prior to any site clearing or grading. 2. Cover Measures — Disturbed Site areas shall be covered with mulch and seeded, as appropriate, for temporary or permanent measures. 3. Perimeter protection — Perimeter protection shall consist of a silt fence down slope of any disturbed areas or stockpiles. 4. Traffic Area Stabilization — A stabilized construction entrance will be located at the point of ingress/egress. 5. Sediment Retention — Permanent storm detention pond will be utilized for sediment retention. Pond outlet will be plugged and water will be pumped as necessary to avoid overflow. Sediment-laden water will be disposed of in a manner approved by the City. Permanent storm detention pond shall be installed prior to grading of any contributing area. 6. Surface Water Control —Interceptor berms or swales shall be installed to control and intercept all surface water from disturbed areas and shall be routed to the detention pond for retention. 7. Dewatering Control —Will be provided as needed. 8. Dust Control — Dust control shall be provided by spraying exposed soils with water until wet. This is required when exposed soils are dry to the point that wind transport is possible which would impact roadways, drainage ways, surface waters, or neighboring residences. 9. Flow Control — During construction, runoff will be conveyed to the permanent flow control facility. The vault outlet will be plugged, preventing runoff from leaving the site until final stabilization. SWPPS PLAN DESIGN (PART B) The complete CSWPPP is included in Appendix A. �2013 D. R. STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 38 of 43 Drainage Report City of Renton SECTION IX BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 1. Bond Quantity Worksheet — will be provided prior to final engineering approval. 2. The Stormwater Facility Summary Sheet is included in this section 3. Declaration of Covenant—will be provided prior to final engineering approval. ' ', �. �. f '. �-- �i � ,� � 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 39 of 43 Drainage Report City of Renton King County Department of Development&Environmental Services 900 Oakesdale Avenue Southwest Renton,Washington 98055-1219 Project Name: Piper's Bluff Date: 2/4/2013 �ocat�or,: 1166 Hoquiam Ave NE, Renton, Washin ton Project No.: LUA12-078, ECF, PP 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. x yes no If yes, Forest Practice Permit Number: (RCW 76.09) Page 1 of 9 _..,.- _ _ .. ..�-. - -.'-�� ,--- � i .. . - �� f�- ..� ,-- _-.� - -; �i �� - ,� ,.. � y_._.__..t. ) , i � Unit #of Reference# Price Unit Quantity Applications Cost EROSION/SEDIMENT CONTROL Backfill &compaction-embankment $ 5.62 CY 290 1 1,629.80 Check dams,4"minus rock SWDM 5.4.6.3 $ 67.51 Each 10 1 675.10 Crushed surfacing 1 1/4"minus WSDOT 9-03.9(3) $ 85.45 CY Ditching $ 8.08 CY 290 1 2,343.20 Excavation-bulk $ 1.50 CY 1 Fence, silt SWDM 5.4.3.1 $ 1.38 LF 1001 1 1,381.38 Fence,Temporary(NGPE) $ 1.38 LF 223 1 307.74 Hydroseedin SWDM 5.4.2.4 $ 0.59 SY 24108 1 14,223.72 Jute Mesh SWDM 5.4.2.2 $ 1.45 SY 0.00 Mulch, by hand, straw, 3"deep SWDM 5.4.2.1 $ 2.01 SY 0.00 Mulch, by machine, straw, 2"deep SWDM 5.4.2.1 $ 0.53 SY 24108 1 12,777.24 Pipin ,tem orary, CPP, 6" $ 10.70 LF 0.00 Piping, temporar , CPP, 8" $ 16.10 LF 0.00 Piping,tempora , CPP, 12" $ 20.70 LF 205 1 4,243.50 Plastic coverin , 6mm thick, sandba ged SWDM 5.4.2.3 $ 2.30 SY 0.00 Ri Rap, machine placed; slopes WSDOT 9-13.1(2) $ 39.08 CY 3 1 117.24 Rock Construction Entrance, 50'x15'x1' SWDM 5.4.4.1 $ 1,464.34 Each 0.00 Rock Construction Entrance, 100'x15'x1' SWDM 5.4.4.1 $ 2,928.68 Each 1 1 2,928.68 Sediment pond riser assembly SWDM 5.4.5.2 $ 1,949.38 Each 0.00 Sediment trap, 5' hi h berm SWDM 5.4.5.1 $ 17.91 LF 0.00 Sed. ond, 5'high, riprapped spillwa berm section SWDM 5.4.5.1 $ 68.54 LF 0.00 Seeding, by hand SWDM 5.4.2.4 $ 0.51 SY 0.00 Sodding, 1"deep, level round SWDM 5.4.2.5 $ 6.03 SY 0.00 Soddin , 1"dee , sloped ground SWDM 5.4.2.5 $ 7.45 SY 0.00 TESC Supervisor $ 74.75 HR 24 1 1,794.00 Water truck, dust control SWDM 5.4.7 $ 97.75 HR 16 1 1,564 00 WRITE-IN-ITEMS **,�* (see page 9) ��,�a��'m,�. ��i�� .� ��, �,< ; SWEEPER TRUCK $ 85.00 HR 6 1 510 INLET PROTECTION $ 25.00 Each 19 1 475 ESC SUBTOTAL: $ 44,970.60 30%CONTINGENCY&MOBILIZATION: $ 13,491.18 ESC TOTAL: $ 58,461.78 COLUMN: A Page 2 of 9 Existing Future Pubiic Private Quantity Completed Right-of-Way Road Improvements Improvements (Bond Reduction)` &Draina e Facilities Quant. Unit Price Unit Quant Cost Quant. Cost Quant. Cost Com lete Cost \7E�ERl1� �=J�MS �` `�`, ,,:�.�i �rr�a�,r,! �^g r ��..'�,5 � �...t .. �,�. ..�.,x�N��n,nN�AHI��i�i91��r b" '4'�'M �d�.. ,�-,�.V 15�.-. ��J��.i+h�II�"�i:u� +�3�� ..' I�L�.r,..,.. I ,�.�a.;.x �� . .,��1 �'r«p XI I l�C �"s �..� ,�,.• `#., §��k�� .� . `� n .. �,.�r Y x _q �. ' .v -,a ,�>: ,T_:..n�.. 7 . , � . ,x . . _ . Backfill&Compaction-embankment $ 5.62 CY $0.00 $0.00 $0.00 $0.00 Backfill&Compaction-trench $ 8.53 CY 210 $1,791.30 427 $3,642.31 237 $2,021.61 $0.00 ' Clear/Remove Brush, b hand $ 0.36 SY $0.00 $0.00 $0.00 $0.00 i Ciearin /Grubbin /Tree Removal $ 8,876.16 Acre 0.237 $2,103.65 1.128 $10,012.31 3.616 $32,096.19 $0.00 I Excavation-bulk $ 1.50 CY 604 $906.00 3892 $5,838.00 8351 $12,526.50 $0.00 I Excavation-Trench $ 4.06 CY 215 $872.90 560 $2,273.60 248 $1,006.88 $0.00 i Fencin , cedar,6'hi h $ 18.55 LF $0.00 $0.00 3319 $61,567.45 $0.00 Fencin ,chain link,vin I coated, 6'hi h $ 13.44 LF $0.00 $0.00 $0.00 $0.00 Fencin ,chain link, ate,vin I coated, 20' $ 1,271.81 Each $0.00 $0.00 $0.00 $0.00 Fencin , split rail,3'hi h $ 12.12 LF $0.00 50 $606.00 $0.00 $0.00 Fill&compact-common barrow $ 22.57 CY $0.00 $0.00 $0.00 $0.00 Fill&com act- ravel base $ 25.48 CY $0.00 $0.00 $0.00 $0.00 Fill 8�compact-screened to soil $ 37.85 CY $0.00 $0.00 $0.00 $0.00 Gabion, 12"deep,stone filled mesh $ 54.31 SY $0.00 $0.00 $0.00 $0.00 Gabion, 18"deep,stone filled mesh $ 74.85 SY $0.00 $0.00 $0.00 $0.00 Gabion,36"dee ,stone filled mesh $ 132.48 SY $0.00 $0.00 $0.00 $0.00 Gradin ,fine, b hand $ 2.02 SY $0.00 $0.00 $0.00 $0.00 Gradin ,fine,with rader $ 0.95 SY $0.00 $0.00 $0.00 $0.00 Monuments, 3'long $ 135.13 Each 2 $270.26 $0.00 $0.00 $0.00 Sensitive Areas Si n $ 2.88 Each $0.00 $0.00 $0.00 $0.00 Soddin , 1"deep,sio ed round $ 7.46 SY $0.00 $0.00 $0.00 $0.00 Surve in , line& rade $ 788.26 Da 1 $788.26 1 $788.26 $0.00 $0.00 Surve in , lot location/lines $ 1,556.64 Acre $0.00 $0.00 3 $4,669.92 $0.00 Traffic control crew(2 fla ers) $ 85.18 HR 48 $4,088.64 $0.00 $0.00 $0.00 Trail,4"chip ed wood $ 7.59 SY $0.00 $0.00 $0.00 $0.00 Trail,4"crushed cinder $ 8.33 SY $0.00 $0.00 $0.00 $0.00 Trail,4"to course $ 8.19 SY $0.00 $0.00 $0.00 $D.00 Wall, retainin ,concrete $ 44.16 SF $0.00 $0.00 $0.00 $0.00 Wall, rockery $ 9.49 SF $0.00 $0.00 653 $6,196.97 $0.00 Page 3 of 9 SUBTOTAL $10,821.01 $23,160.48 $120,085.52 $0.00 Existing Future Public Private Bond Reduction` Right-of-way Road Improvements Improvements &Draina e Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Com lete Cost ��+I '-M M I � � h 11 : .��k A �" Y 1.t ROAD IMPROVEMENT� `�� ,�,a �� ,�� F_�,:� „ . �=eGp��:�,."� �� :�. � � ., AC Grindin ,4'wide machine< 1000sy $ 23.00 SY $0.00 $0.00 $0.00 $0.00 AC Grindin ,4'wide machine 1000-2000s $ 5.75 SY $0.00 $0.00 $0.00 $0.00 AC Grinding,4'wide machine>2000s $ 1.38 SY $0.00 $0.00 $0.00 $0.00 AC Removal/Dis osal/Re air $ 41.14 SY 468 $19,253.52 $0.00 $0.00 $0.00 Barricade,t e I $ 30.03 LF $0.00 $0.00 $0.00 $0.00 Barricade, pe III Permanent $ 45.05 LF $0.00 $0.00 $0.00 $0.00 Curb&Gutter, rolled $ 13.27 LF $0.00 $0.00 $0.00 $0.00 Curb&Gutter,vertical $ 9.69 LF 326 $3,158.94 1839 $17,819.91 $0.00 $0.00 Curb and Gutter,demolition and disposal $ 13.58 LF 15 $203.70 $0.00 $0.00 $0.00 Curb,extruded as halt $ 2.44 LF $0.00 $0.00 $0.00 $0.00 Curb,extruded concrete $ 2.56 LF $0.00 $0.00 $0.00 $0.00 Sawcut,as halt,3"depth $ 1.85 LF 370 $684.50 $0.00 $0.00 $0.00 Sawcut,concrete, er 1"de th $ 1.69 LF $0.00 $0.00 $0.00 $0.00 Sealant, asphalt $ 0.99 LF 345 $341.55 $0.00 $0.00 $0.00 Shoulder,AC, (see AC road unit rice $ - SY $0.00 $0.00 $0.00 $0.00 Shoulder, ravel,4"thick $ 7.53 SY $0.00 $0.00 $0.00 $0.00 Sidewalk,4"thick $ 30.52 SY $0.00 $0.00 $0.00 $0.00 Sidewalk,4"thick,demolition and disposal $ 27.73 SY $0.00 $0.00 $0.00 $0.00 Sidewalk, 5"thick $ 34.94 SY 200 $6,988.00 1036 $36,197.84 $0.00 $0.00 Sidewalk,5"thick,demolition and dis osal $ 34.65 SY 9 $311.85 $0.00 $0.00 $0.00 Si n, handicap $ 85.28 Each $0.00 $0.00 $0.00 $0.00 Stri in , er stall $ 5.82 Each $0.00 $0.00 $0.00 $0.00 Stripin ,thermoplastic, for crosswalk) $ 2.38 SF $0.00 $0.00 $0.00 $0.00 Striping,4"reflectorized line $ 0.25 LF $0.00 $0.00 $0.00 $0.00 Page 4 of 9 SUBTOTAL $30,942.06 $54,017.75 $0.00 $0.00 Existing Future Public Private Bond Reduction* Right-of-way Road Improvements Improvements 8�Drainage Facilities Quant. ' Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost ROAD SURFACING`��'�;;4",RoCk�=2.5`base&1,.5,;tqp�Coul'S2)`�'<For'93 KCIi aCk=5"base&;, ,"N�irs��e) y; ' *� �p�h' ..��M�yu�r '.,,�; , � �� `'�? ?� t :��,��:»�°�i;�� For KCRS'93, (additional 2.5"base)add: $ 3.60 SY $0.00 $0.00 $0.00 $0.00 AC Overla , 1.5"AC $ 7.39 SY $0.00 $0.00 $0.00 $0.00 AC Overla ,2"AC $ 8.75 SY 643 $5,626.25 2625 $22,968.75 1075 $9,406.25 $0.00 AC Road,2",4"rock, First 2500 SY $ 17.24 SY 185 $3,189.40 2625 $45,255.00 1075 $18,533.00 $0.00 AC Road,2",4"rock,Qt . over 2500SY $ 13.36 SY $0.00 $0.00 $0.00 $0.00 AC Road, 3",4"rock, First 2500 SY $ 19.69 SY $0.00 $0.00 $0.00 $0.00 AC Road,3",4"rock,Qt .over 2500 SY $ 15.81 SY $0.00 $0.00 $0.00 $0.00 AC Road,5", First 2500 SY $ 14.57 SY $0.00 $0.00 $0.00 $0.00 AC Road,5",Qt .Over 2500 SY $ 13.94 SY $0.00 $0.00 $0.00 $0.00 AC Road,6", First 2500 SY $ 16.76 SY $0.00 $0.00 $0.00 $0.00 AC Road,6",Qt .Over 2500 SY $ 16.12 SY $0.00 $0.00 $0.00 $0.00 Asphalt Treated Base,4"thick $ 9.21 SY 185 $1,703.85 2625 $24,176.25 1075 $9,900.75 $0.00 Gravel Road,4"rock, First 2500 SY $ 11.41 SY $0.00 230 $2,624.30 $0.00 $0.00 Gravel Road,4"rock,Qt .over 2500 SY $ 7.53 SY $0.00 $0.00 $0.00 $0.00 PCC Road, 5", no base, over 2500 SY $ 21.51 SY $0.00 $0.00 $0.00 $0.00 PCC Road, 6", no base,over 2500 SY $ 21.87 SY $0.00 $0.00 $0.00 $0.00 Thickened Edge $ 6.89 LF $0.00 $0.00 $0.00 $0.00 Page 5 of 9 SUBTOTAL $10,519.50 $95,024.30 $37,840.00 $0.00 Existing Future Public Private Bond Reduction* Right-of-way Road Improvements Improvements 8�Drainage Facilities Quant. Unit Price Unit Quant. Cost Quant, Cost Quant. Cost Complete Cost DRAINAGE��(CPP=CorrugatedPlasticPipe,`I��wor�Equivalent) �� ; �� ,�;�orCuivertpr�ces, A3�r.aq �.� erti�a�H�`ssumea�;assittn��, , �'�ipriceas�soi�dpt��.; ��%��,�„� Access Road, R/D $ 16.74 SY $0.00 230 $3,850.20 $0.00 $0.00 Boilards-fixed $ 240.74 Each $0.00 $0.00 $0.00 $0.00 Bollards-removable $ 452.34 Each $0.00 $0.00 $0.00 $0.00 " CBs include frame and lid CB T e I $ 1,257.64 Each 4 $5,030.56 15 $18,864.60 3 $3,772.92 $0.00 CB T e IL $ 1,433.59 Each $0.00 1 $1,433.59 $0.00 $0.00 CB T pe II,48"diameter $ 2,033.57 Each $0.00 1 $2,033.57 $0.00 $0.00 for additional depth over 4' $ 436.52 FT $0.00 1 $436.52 $0.00 $0.00 CB T pe II, 54"diameter $ 2,192.54 Each $0.00 2 $4,385.08 $0.00 $0.00 for additional de th over 4' $ 486.53 FT $0.00 2 $973.06 $0.00 $0.00 CB T e II,60"diameter $ 2,351.52 Each $0.00 $0.00 $0.00 $0.00 for additional depth over 4' $ 536.54 FT $0.00 $0.00 $0.00 $0.00 CB T e II,72"diameter $ 3,212.64 Each $0.00 $0.00 $0.00 $0.00 for additional de th over 4' $ 692.21 FT $0.00 $0.00 $0.00 $0.00 Throu h-curb Inlet Framework Add $ 366.09 Each $0.00 2 $732.18 $0.00 $0.00 Cleanout, PVC,4" $ 130.55 Each $0.00 49 $6,396.95 $0.00 $0.00 Cleanout, PVC,6" $ 174.90 Each $0.00 $0.00 $0.00 $0.00 Cleanout, PVC,8" $ 224.19 Each $0.00 $0.00 $0.00 $0.00 Culvert, PVC,4" $ 8.64 LF $0.00 $0.00 $0.00 $0.00 Culvert, PVC,6" $ 12.60 LF $0.00 $0.00 1202 $15,145.20 $0.00 Culvert, PVC, 8" $ 13.33 LF $0.00 $0.00 $0.00 $0.00 Culvert, PVC, 12" $ 21.77 LF $0.00 $0.00 $0.00 $0.00 Culvert,CMP,8" $ 17.25 LF $0.00 $0.00 $0.00 $0.00 Culvert,CMP, 12" $ 26.45 LF $0.00 $0.00 $0.00 $0.00 Culvert,CMP, 15" $ 32.73 LF $0.00 $0.00 $0.00 $0.00 Culvert, CMP, 18" $ 37.74 LF $0.00 $0.00 $0.00 $0.00 , Culvert,CMP,24" $ 53.33 LF $0.00 $0.00 $0.00 $0.00 �� Culvert,CMP,30" $ 71.45 LF $0.00 $0.00 $0.00 $0.00 Culvert,CMP,36" $ 112.11 LF $0.00 $0.00 $0.00 $0.00 Culvert, CMP,48" $ 140.83 LF $0.00 $0.00 $0.00 $0.00 Culvert,CMP,60" $ 235.45 LF $0.00 $0.00 $0.00 $0.00 Culvert,CMP,72" $ 302.58 LF $0.00 $0.00 $0.00 $0.00 Page 6 of 9 SUBTOTAL $5,030.56 $39,105.75 $18,918.12 $0.00 Existing Future Public Private Bond Reduction* Right-of-way Road Improvements Improvements DRAINAGE CONTINUED &Drainage Facilities Quant. Unit Price Unit Quant Cost Quant. Cost Quant. Cost - Com lete Cost - Culvert, Concrete,8" $ 21.02 LF $0.00 $0.00 $0.00 $0.00 , Culvert,Concrete, 12" $ 30.05 LF $0.00 $0.00 $0.00 $0.00 Culvert,Concrete, 15" $ 37.34 LF $0.00 $0.00 $0.00 $0.00 Culvert,Concrete, 18" $ 44.51 LF $0.00 $0.00 $0.00 $0.00 li Culvert,Concrete,24" $ 61.07 LF $0.00 $0.00 $0.00 $0.00 �I Culvert, Concrete,30" $ 104.18 LF $0.00 $0.00 $0.00 $0.00 Culvert, Concrete,36" $ 137.63 LF $0.00 $0.00 $0.00 $0.00 Culvert, Concrete,42" $ 158.42 LF $0.00 $0.00 $0.00 $0.00 Culvert,Concrete,48" $ 175.94 LF $0.00 $0.00 $0.00 $0.00 Culvert,CPP,6" $ 10.70 LF $0.00 23 $246.10 $0.00 $0.00 Culvert, CPP, 8" $ 16.10 LF $0.00 $0.00 $0.00 $0.00 Culvert, LCPE, 12" $ 20.70 LF 379 $7,845.30 1153 $23,867.10 63 $1,304.10 $0.00 Culvert, CPP, 15" $ 23.00 LF $0.00 $0.00 $0.00 $0.00 Culvert, LCPE,24" $ 38.30 LF $0.00 147 $5,630.10 $0.00 $0.00 Culvert,CPP, 18" $ 27.60 LF $0.00 197 $5,437.20 $0.00 $0.00 Culvert, CPP,24" $ 36.80 LF $0.00 $0.00 $0.00 $0.00 Culvert, CPP, 30" $ 48.30 LF $0.00 $0.00 $0.00 $0.00 Culvert,CPP,36" $ 55.20 LF $0.00 $0.00 $0.00 $0.00 Ditchin $ 8.08 CY $0.00 $0.00 $0.00 $0.00 Interceptor Trench (1,436 base+ $ 25.99 LF $0.00 $0.00 $0.00 $0.00 French Drain (3'depth) $ 22.60 LF $0.00 $0.00 $0.00 $0.00 Geotextile, laid in trench, pol ro lene $ 2.40 SY $0.00 $0.00 $0.00 $0.00 Infiltration pond testin $ 74.75 HR $0.00 $0.00 $0.00 $0.00 Mid-tank Access Riser,48"dia, 6'dee $ 1,605.40 Each $0.00 $0.00 $0.00 $0.00 Pond Overtlow S illwa $ 14.01 SY $0.00 $0.00 $0.00 $0.00 Restrictor/Oil Se arator, 12" $ 1,045.19 Each $0.00 $0.00 $0.00 $0.00 Restrictor/Oil Separator, 15" $ 1,095.56 Each $0.00 $0.00 $0.00 $0.00 Restrictor/Oil Separator, 18" $ 1,146.16 Each $0.00 1 $1,146.16 $0.00 $0.00 Riprap,placed $ 39.08 CY 4 $156.32 $0.00 12 $468.96 $0.00 Tank End Reducer(36"diameter $ 1,000.50 Each $0.00 $0.00 $0.00 $0.00 Trash Rack, 12" $ 211.97 Each 1 $211.97 $0.00 $0.00 $0.00 Trash Rack, 15" $ 237.27 Each $0.00 $0.00 $0.00 $0.00 Trash Rack, 18" $ 268.89 Each $0.00 $0.00 $0.00 $0.00 Trash Rack,21" $ 306.84 Each $0.00 $0.00 $0.00 $0.00 Trash Rack,24" $ 344.79 Each $0.00 1 $344.79 $0.00 $0.00 Page 7 of 9 SUBTOTAL $8,213.59 $36,326.66 $1,773.06 $0.00 Existing Future Public Private Bond Reduction' Right-of-way Road Improvements Improvements 8.Drainage Facilities Quant Unit Price Unit Quant. Price Quant. Cost Quant. Cost Complete Cost PARKING LOT SURFACING ,��,�� '�'�'�'��'�°,� ;�x .,..,_ .. �,� �_;3 . ..., , � ��.��;" °�"�..� �� :. . ,. �� 4 . : �. . r ... _,�:�. �.. r � : 2"AC,2"top course rock&4"borrow $ 15.84 SY $0.00 $0.00 $0.00 $0.00 2"AC, 1.5" top course& 2.5"base course $ 17.24 SY $0.00 $0.00 $0.00 $0.00 4"select borrow $ 4.55 SY $0.00 $0.00 $0.00 $0.00 1.5"to course rock&2.5"base course $ 11.41 SY $0.00 $0.00 $0.00 $0.00 WRITE•-1N-ITEMS ''"`�` �'. - , , , ,a , , � A ;,r� � :� . ,a.: . > � � � . , � t ... : l F•, . . . , .... �r.i Fe � � �, yG� }� �r -..�- .. �, ��Mk�`1�l'S?3 . � .,a a'� , �"9�� .'.. fl��'��'aX�S�-av�-n-�`�n��'wi�', -�'+,�,� . �� a �e, Detention Pond Retainin Wall $ 350 CY $0.00 294 $102,900.00 $0.00 $0.00 StormFilter,96"dia. Manhole $37,700 EA. $0.00 1 $37,700.00 $0.00 $0.00 LF $0.00 $0.00 $0.00 $0.00 EA. $0.00 $0.00 $0.00 $0.00 EA. $0.00 $0.00 $0.00 $0.00 EA. $0.00 $0.00 $0.00 $0.00 LF $0.00 $0.00 $0.00 $0.00 SF $0.00 $0.00 $0.00 $0.00 LF $0.00 $0.00 $0.00 $0.00 LF $0.00 $0.00 $0.00 $0.00 SUBTOTAL $0.00 $140,600.00 $0.00 $0.00 SUBTOTAL(SUM ALL PAGES): $65,526.72 $388,234.94 $178,616.70 $0.00 30%CONTINGENCY&MOBILIZATION: $19,658.02 $116,470.48 $53,585.01 $0.00 GRANDTOTAL: $85,184.74 $504,705.42 $232,201.72 $0.00 COLUMN: B C D E Page 8 of 9 Original bond computations prepared by: LUBy R.JOUd@h, P.E. I Name: Piper's Bluff Date: 4-Feb-13 PE Registration Number: 32162 Tel.#: (425)827-3063 Firm Name: D. R. STRONG Consulting Engineers, Inc. Address: 10604 NE 38th P18Ce,#101; Kirkland,WA 98033 ProjectNo: LUA12-078, ECF, PP ROAD IMPROVEMENTS&DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND' PUBLIC ROAD&DRAINAGE AMOUNT BOND•AMOUNT MAINTENANCE/DEFECT BOND* REQUIRED AT RECORDING OR Stabilization/Erosion Sediment Control(ESC) (A) $ 58,461.8 TEMPORARY OCCUPANCY'•' Existing Right-of-Way Improvements (B) $ 85,184.7 Future Public Road Improvements&Drainage Fa (C) $ 504,705.4 Private Improvements (D) $ 232,201.7 Calculated Quantity Completed (E) $ - Total Right-of Way and/or Site Restoration Bond* (A+B) $ 143,646.5 (First$7,500 of bond'shall be cash.) Performance Bond"Amc(A+B+C+D) = TOTAL (T) $ 880,553.7 T x 0.30 $ 264,166.1 OR Minimum bond'amount is$1000. Reduced Performance Bond*Total*** (T-E) $ 880,553.7 Use larger of Tx30%or(T-E) (B+C)x Maintenance/Defect Bond'Total 0.25= $ 147,472.5 NAME OF PERSON PREPARING BOND'REDUCTION Date: *NOTE: The word"bond"as used in this document means any financial guarantee acceptable to King County. **NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required. The restoration requirement shall include the total cost for ail TESC as a minimum,not a maximum. In addition,corrective work,both on-and off-site needs to be included. Quantities shail reflect worse case scenarios not just minimum requirements. For example,if a salmonid stream may be damaged,some estimated costs for restoration needs to be reflected in this amount. The 30%contingency and mobilization costs are computed in this quantity. "'NOTE: Per KCC 27A,total bond amounts remaining after reduction shall not be less than 30%of the original amount(T)or as revised by major design changes. SURETY BOND RIDER NOTE: If a bond rider is used,minimum additional pertormance bond shall be $ - (C+D)-E REQUIRED BOND'AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DDES STORMWATER FACILITY SUMMARY SHEET Development Piper's Biuff Date Januarv 23, 2012 Location 1166 Hoquiam Avenue NE, Renton, Washinqton ENGINEER DEVELOPER Name Luay R. Joudeh, P.E. Name Firm D. R. STRONG Consulting Firm WestPac Development, LLC En ineers, Inc. Address 10604 NE 38 Place, #101 Address 7449 W. Mercer Wa Kirkland, WA 98033 Mercer Island, WA 98040 Phone (425) 827-3063 Phone (206) 770-6546 Developed Site: 4.98 acres Number of lots 28 Number of detention facilities on site: Number of infiltration facitities on site: vaults vaults 1 pond vaults tanks tanks Flow control provided in regional facility (give location) No flow control required Exemption number Downstream Draina e Basins Immediate Major Basin Basin Ma Creek May Creek Number & type of water quality facilities on site: biofiltration swale (regular/wet/or continuous inflow?) sand filter (basic or large?) sand filter, linear (basic or large?) 1_CONTECH Stormfilter combined detentionNVQ vault sand filter vault (basic or large?) combined detention/wetvault stormwater wetland compost filter wetvault (basic or large?) filter strip Wetvault flow dispersion pre-settling pond farm management plan flow-splitter catchbasin landscape management plan oil/water separator (baffle or coalescing plate?) catch basin inserts: G�2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 40 of 43 Drainage Report City of Renton Manufacturer pre-settling structure: Manufacturer DESIGN INFORMATION INDIVIDUAL BASIN Water Quali design flow Water Quali treated volume Draina e basin s) Onsite area (inlcudes fronta e 4.98 Offsite area 0 T e of Stora e Facilit Pond Live Stora e Volume (required) 69,132 Predev Runoff Rate 2- ear 0.139 10- ear 0.241 100- ear 0.402 Developed Runoff Rate 2- ear 0.928 10- ear 1.12 100- ear 1.88 T pe of Restrictor Frop-Tee Size of orifice/restriction No. 1 0.88 No. 2 1.50 No. 3 1.40 I I I ; 02013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 41 of 43 Drainage Report City of Renton SECTION X OPERATIONS AND MAINTENANCE MANUAL The Type 1-L catch basins have a one-foot deep sump, and the Type 2 catch basins have a two-foot deep sump for sediment accumulation. These sumps should be periodically checked and the sediment removed when accumulated to more than 1/3 of the depth from the bottom of the basin to the invert of the lowest pipe into or out of the basin. Grates should be cleaned when trash or debris of more than '/ cubic foot is located immediately in front of the basin opening, or is blocking capacity of the basin by more than 10%. Conveyance pipes should be periodically checked and cleaned when more than 20% of the pipe diameter is obstructed by accumulated sediment or debris. Accumulated sediment and stagnant conditions may cause noxious gases to form and accumulate in the vertical wall pond. Sediment in the vertical wall pond should be removed when the 1/2-foot sediment zone is full plus 6 inches. Sediment should be tested for toxicants in compliance with current disposal requirements if visual or olfactory indications of pollution are noticed. Water drained or pumped from pond prior to sediment removal may be discharged to the downstream conveyance (i.e. roadside ditch), if it is not excessively turbid (i.e. if water appears translucent when held to light), and if floatable debris and visual petroleum sheens are removed. Excessively turbid water (i.e. water appears opaque when held to light) should be discharged only after the solids have been removed. Floating debris and accumulated petroleum products should be removed as needed, but at least annually. The floating oil should be removed from wetpond used as oil/water separators when oil accumulation exceeds one inch. The vertical wall pond should be maintained similarly to the vault with the following additional requirements. Site vegetation should be trimmed as necessary to keep the pond free of leaves and to maintain the aesthetic appearance of the site. Slope areas that have become bare should be revegetated and eroded areas should be regraded prior to being revegetated. Perform inspections of all components quarterly during the first year of operation, then annually thereafter. For more detailed maintenance instructions, refer to the standards contained at the end of this section. The maintenance of the Stormfilter vault is described in the following summary provided by the manufacturer with annual maintenance recommendations. :,2013 D. R.STRONG Consulting Engineers Inc. PipePs Bluff Plat Page 42 of 43 Drainage Report City of Renton I __ __ _ ___ I , �i A��%\�TCA�.■a � Important: Inspection should be performed by a person who is ��,��r� TheStormw.ee�Ma�gemrnt familiar with the StormFilter treatment unit. � STORMWATER StormFilter , SOLUTIONS_ 1.If applicable, set up safety equipment to protect and notify � surrounding vehicle and pedestrian traffic. StormFilter Maintenance Guidelines 2.Visually inspect the external condition of the unit and take notes Maintenance requirements and frequency are dependent on the concerning defects/problems. pollutant load characteristics of each site,and may be required in 3.Open the access portals to the vault and allow the system vent. the event of a chemical spill or due to excessive sediment loading. 4.Without entering the vault,visually inspect the inside of the unit, Maintenance Procedures and note accumulations of liquids and solids. Although there are other effective maintenance options,CONTECH 5. Be sure to record the level of sediment build-up on the floor of recommends the following two step procedure: the vault, in the forebay,and on top of the cartridges. If flow is occurring, note the flow of water per drainage pipe. Record 1. Inspedion: Determine the need for maintenance. all observations. Digital pictures are valuable for historical 2. Maintenance:Cartridge replacement and sediment removal. documentation. Inspection and Maintenance Acti�ity Timing 6.Close and fasten the access portals. ' At least one scheduled inspection activity should take place per year 7. Remove safety equipment. with maintenance following as warranted. 8. If appropriate,make notes about the local drainage area relative First, inspection should be done before the winter season. During to ongoing construdion,erosion problems, or high loading of which,the need for maintenance should be determined and, if other materials to the system. disposal during maintenance will be required,samples of the 9.Discuss conditions that suggest maintenance and make decision accumulated sediments and media should be obtained. as to weather or not maintenance is needed. Second, if warranted, maintenance should be performed during Maintenance Decision Tree periods of dry weather. The need for maintenance is typically based on results of the inspection. In addition,you should check the condition of the StormFilter unit Use the following as a general guide. (Other factors,such as regulatory after major storms for potential damage caused by high flows and requirements,may need to be considered) for high sediment accumulation. It may be necessary to adjust the 1. Sediment loading on the vault floor. If>4"of accumulated inspection/maintenance adivity schedule depending on the actual sediment,then go to maintenance. operating conditions encountered by the system. 2.Sediment loading on top of the cartridge. If >1/4"of Generally, inspection activities can be conducted at any time,and accumulation,then go to maintenance. maintenance should occur when flows into the system are unlikely. 3.Submerged cartridges. If >4"of static�vater in the cartridge Maintenance Activity Frequency bay for more that 24 hrs after end of rain event,then go to P�laintenance is performed on an as needed basis, based on maintenance. inspection. Average maintenance lifecycle is 1-3 years. The primary 4. Plugged media. If pore space between media granules is absent, factor controlling timing of maintenance of the StormFilter is then go to maintenance. sediment loading. Until appropriate timeline is determined, use the 5. Bypass condition. If inspection is conducted during an average following: rain fall event and StormFilter remains in bypass condition Inspection: (water over the internal outlet baffle wall or submerged One time per year cartridges),then go to maintenance. After major storms 6. Hazardous material release. If hazardous material release (automotive fluids or other) is reported,then go to Maintenance: maintenance. As needed 7.Pronounced scum line. If pronounced scum line(say>_ t/4" Per regulatory requirement thick)is present above top cap,then go to maintenance. In the event of a chemical spill 8.Calendar Lifecycle. If system has not been maintained for 3 Inspection Procedures years,then go to maintenance. Assumptions: It is desirable to inspect during a storm to observe the relative flow through the filter cartridges. If the submerged cartridges are No rainfall for 24 hours or more. see�erely plugged,then typically large amounts of sediments will be No upstream detention (at least not draining into StormFilter). present and very little flow will be discharged from the drainage Structure is online. Outlet pipe is clear of obstruction. Construction pipes. If this is the case,then maintenance is warranted and the bypass is plugged. cartridges need to be replaced. Maintenance Warning: In the case of a spill,the worker should abort inspedion Depending on the configuration of the particular system, workers activities until the proper guidance is obtained. Notify the Will be required to enter the vault to perform the maintenance. local hazard control agency and CONTE�H immediately. To conduct an inspection: 1 Important: If vault entry is required, OSHA rules for confined space Method 2: entry must be followed. A. Enter the vault using appropriate confined space protocols. Filter cartridge replacement should occur during dry weathec It may be necessary to plug the filter inlet pipe if base flow is occurring. B• Unscrew the cartridge cap. Replacement cartridges can be delivered to the site or customers C. Remove the cartridge hood screws(3)hood and float. facility. Contact CONTECH for more information. D. At location under structure access,tip the cartridge on its Warning: In the case of a spill,the worker should abort side. maintenance activities until the proper guidance is obtained. Notify the local hazard control agency and CONTECH immediately. Important: Note that cartridges containing media other than the leaf inedia require unscrewing from their threaded To conduct cartridge replacement and sediment removal: connectors.Take care not to damage the manifold 1. If applicable, set up safety equipment to protect workers and connectors.This connector should remain installed in the pedestrians from site hazards. manifold and capped if necessary. 2.Visually inspect the external condition of the unit and take notes E. Empty the cartridge onto the vault floor. Reassemble the concerning defects/problems. empty cartridge. 3.Open the doors(access portals)to the vault and allow the system to vent. F. Set the empty, used cartridge aside or load onto the hauling truck. 4.Without entering the vault, give the inside of the unit, including components,a general condition inspection. G. Continue steps a through E until all cartridges have been 5. Make notes about the external and internal condition of removed. the vault. Give particular attention to recording the level of g, Remove accumulated sediment from the floor of the vault and sediment build-up on the floor of the vault, in the forebay,and from the forebay. Use vacuum truck for highest effectiveness. on top of the internal components. 9. Once the sediments are remo�ed, assess the condition of the 6. Using appropriate equipment offload the replacement cartridges vault and the connectors.The connectors are short sections (up to 150 Ibs. each)and set aside. of 2-inch schedule 40 PVC,or threaded schedule 80 PVC that 7. Remove used cartridges from the vault using one of the should protrude about 1"above the floor of the vault. Lightly following methods: wash down the vault interior. Method 1: a. If desired,apply a light coating of FDA approved silicon A. This activity will require that workers enter the vault to lube to the outside of the exposed portion ot the remove the cartridges from the under drain manifold and connectors.This ensures a watertight connection between place them under the vault opening for lifting {removal). the cartridge and the drainage pipe. Unscrew(counterclockwise rotations)each filter cartridge from the underdrain connector. Roll the loose cartridge,on b. Replace any damaged connectors. edge,to a convenient spot beneath the vault access. 10. Using the vacuum truck boom,crane,or tripod, lower and Using appropriate hoisting equipment,attach a cable from install the new cartridges.Take care not to damage connections. the boom,crane,or tripod to the loose cartridge. Contact 11.Close and fasten the door. CONTECH for suggested attachment devices. 1�. Remove safety equipment. Important:Cartridges containing leaf inedia (CSF)do not 13. Finally,dispose of the accumulated materials in accordance with require unscrewing from their connectors. Do not applicable regulations. Make arrangements to return the used damage the manifold connectors.They should remain empty cartridges to CONTECH. installed in the manifold and can be capped during the Material Disposal maintenance activity to prevent sediments from entering The accumulated sediment must be handled and disposed of in the under drain manifold. accordance with regulatory protocols. It is possible for sediments B. Remove the used cartridges(up to 250 Ibs.)from the vault. to contain measurable concentrations of heavy metals and organic chemicals.Areas with the greatest potential for high pollutant Important:Avoid damaging the cartridges during removal and loading include industrial areas and heavily traveled roads. installation. Sediments and water must be disposed of in accordance with C. Set the used cartridge aside or load onto the hauling truck. applicable waste disposal regulations. Coordinate disposal of solids D. Continue steps A through �until all cartridges have been and liquids as part of your maintenance procedure. Contact the removed. local public works department to inquire how they disposes of their street Uiaste residuals. ��2007 CONTECH Stormwater Solutions 800.925.5240 contechstormwateccom Nothing in this catalog should be construed as an expressed warranty or an implied warranty of inerchantability or fitness for any particular purpose. See the CONTECH standard quotation or acknowledgement for applicable warranties and other terms and conditions of sale. The productls)described may be protected 6y one or more of the following US patents: 5,322,629;5,624,576;5,707,527;5,759,415;5,788,848;5,985.157; 6,027.639;6,350,374;6,406,218;6,611,720;6,511,555;6,649,048;6,991,114;6,998,038;7,186,058;related foreign patents or other patents pending. 2 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACII.ITIES NO. 3-CLOSED DETENTION SYSTEMS(PIPESfTANKS) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Storage Area Plugged Air Vents One-half of tt�e cross section of a vent is blocked at Vents free of debris and any point with debris and sediment sediment Debris and Accumulated sediment depth exceeds 10%of the All sediment and debris Sediment diameter of the storage area for'/z length of storage removed from storage area. vault or any point depth exceeds 15%of diameter. ' Example:72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than'/z length of tank. Joints Between Any crack ailowing material to be transported into All joint between tank/pipe Tank/Pipe Section facility sections are sealed Tank Pipe Bent Any part of tank/pipe is bent out of shape more than TanW pipe repaired or replaced Out of Shape 10%of iYs design shape to design. Manhole Cover Not in Place Cover is missing or oniy partially in place.Any open Manhole is closed. manhole requires maintenance. Locking Mechanism cannot be opened by one maintenance Mechanism opens with proper Mechanism Not person with proper tools.Bolts into frame have less tools. Working than 3'z inch of thread(may not appfy to self-locking lids.) Cover Difficuft to One maintenance person cannot remove lid after Cover can be removed and Remove applying 801bs of lift. Intent is to keep cover from reinstalled by one maintenance sealing off access to maintenance. person. Ladder Rungs King County Safety Office and/or maintenance person Ladder meets design standards Unsafe judges that ladder is unsafe due to missing rungs, allows maintenance person safe misalignment,rust,or cracks. access. Catch Basins See"Catch Basins"Shndards No.5 See"Catch Basins"Standards No.5 1998 Surface Water Design Manual 9/1/98 A-3 APPENDIX A MAINTEN.ANCE STANDARDS FOR PRNATELY MAINTAIIv'ED DRAINAGE FACILITIES NO. 4-CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Pertormed General Trash and Debris Distance between debris build-up and bottom of All trash and debris removed. (Includes Sediment) orifice plate is less than 1-1/2 feet Structura!Damage Structure is not securely attached to manhofe wall Structure securely attached to and outlet pipe structure should support at least wall and ouUet pipe. 1,�00 Ibs of up or down pressure. Structure is not in upright position(allow up to Structure in correct position. 109'o from plumb). Connections to oudet pipe are not watertight and Connections to outfet pipe are show signs of rust water tight;structure repaired or replaced and works 2s designed. Any holes—otherthan designed holes—in the Structure has no holes other structure. than designed holes. Cleanout Gate Damaged or Missing Cleanout gate is not watertight or is missing. Gate is watertight and works as � designed. Gate cannot be moved up and down by one Gate moves up and down easily ' maintenance person. and is watertight. Chain teading to gate is missing or damaged. Chain is in place and works as designed. Gate is rusted over 50%of its surface area. Gate is repaired or replaced to meet design standards.. - Orifice P(ate Damaged or Missing ConVol device is not working properly due to Plate is in place and works as missing,out of place,or bent orifice plate. designed. Obstructions Any Vash,debris,s?dim�nt,or vegetation Plate is free of all obstructions blocking the plate. and works as designed. Overflow Pipe Obstructions Any trash or debris blocking(or having the Pipe is free of all obstructions potential of blocking)the overflow pipe. and works as designed. Manhole See"Closed Detention Systems"Standards No.3 See"Closed Detention Systems' Standards No.3 Catch Basin See°Catch Basins"Standards No.5 See'Catch Basins"Standards No.5 9/1/98 1998 Surface�'��ater Desi�n Aianual A-4 APPENDIX A MAIIVTENAIv'CE STANDARDS FOR PRIVATELY NIAINTAINED DRAL'VAGE FACILITTES NO.5-CATCH BASlNS Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is pertormed General Trash&Debris Trash or debris of more than 1/2 cubic foot which is No Trash or debris located (Includes Sediment) located immediately in front of the catch basin immediately in front of catch opening or is blocking capacity of the basin by basin opening. more than 10% Trash or debris(in the basin)that exceeds 1/3 the No trash or debris in the catch depth from the bottom of basin to invert ihe lowest basin. pipe into or out of the basin. Trash or debris in any inlet or outlet pipe blocking Inlet and outiet pipes free of more than 1/3 of its height trash or debris. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within the catch basin. gases(e.g.,methane). Deposits of garbage exceeding 1 cubic foot in No condition present which volume would attract or support the breeding of insects or rodents. Structure Damage to Comer of frame extends more than 3/4 inch past Frame is even with curb. Frame 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 wider than 1/4 inch Cntent is to make sure cracks. atl material is running into basin). Frame not sitting flush on top slab,i.e.,separation Frame is sitting flush on top of more than 3/4 inch of the frame from the top slab. slab. Cracks in Basin Walls/ Cracks wider than 1/2 inch and longer than 3 feet, Basin rep{aced or repaired to Bottom any evidence of soil particles entering catch basin design standards. through cracks,or maintenance person judges that structura is unsound. Cracks wider than 1/2 inch and longer than 1 foot N�cracks more than 1/4 inch at the joint of any inleU outlet pipe or any evidence wide at the jant of inleVoutlet of soil particles entering catch basin through pipe. cracks. SedimenU Basin has settled more than 1 inch or has rotated Basin replaced or repaired to Misalignment more than 2 inches out of alignment. design standards. 1998 Surface Water Desi�►Manual 9/1/98 A-5 �PPENDIX A I�ZAINTENANCE ST?��TDARDS FO�PRIVATELY 47AINT:�INED DRAihAGE FACILI i fES NO. 5-CATCH BASINS (CONTINUED� Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed ______._._ Fire Hazard Presence of chemicals such as naturaJ gas,oil and No flammable chemicals gasoline. present Vegetation Vegetation growing across and biocking more than No vegetation blocking open! ' • 10%of the basin opening. to basin. Vegetation growing in inleUoutfet pipe joints that is No vegetation or root growth more than six inches tall and less than six inches present. apart. Pollution Nonflammable chemicals of more than 1/2 cubic foot No pollution present other than per three feet of basin length. surface film. Catch Basin Cover Cover Not in Place' Cover is missing or only partially in place.Any open Catch basin cover is closed catch basin requires maintenance. . Locking Mechanism Mechanism cannot be opened by on maintenance Mechanism opens with proper Not Working person with proper tools.Bolts into frame have less tools. than 1/2 inch of thread. Cover Difficult to One maintenance person cannot remove lid after Cover can be removed by one Remove applying 80 Ibs.of lift;intent is keep cover from maintenance person. seating off access to maintenance. Ladder Ladder Rungs Ladder is unsafe due to missing rungs,misalignment, Ladder meets design standards Unsafe rust,cracks,or sharp edges. and allows maintenance person safe access. Metal Grates Grate with opening wider than 7/8 inch. Grate opening meets design (If Applicable) standards. Trash and Debris Trash and debris that is blocking mare than 20%of Grate ftee of trash and debris. � grate surtace. ' Damaged or Grate missing or broken member(s)of the grate. Grate is in place and meets Missing. design standards. NO. 6 DEBRtS BARR{ERS(E.G.,TRASH RACKS) Maintenance Defect Condition When Maintenance is Needed Results Expected When Components Maintenance is Performed. General Trash and Debris Trash or debris that is plugging more than 20%of Barrier Gear to receive capacity the openings in the barrier. flow. Metal Damaged/Missing Bars are bent out of shape more than 3 inches. Bars in place with no bends more Bars. than 314 inch. Bars are missing or entire barrier missing. Bars in place according to design. Bars are loose and rust is causing 509'o deterioration Repair or replace barrier to to any part of barrier. design standards. 9/1/98 1998 Surface Water Desi�n Manual A-6 I�� APPENDIX A MAINTENANCE ST.ANDARDS FOR PRNATELY MAINTAINED DRAINAGE FACILITIES NO. 7- ENERGY DISSIPATERS Maintenance Defect Conditions When Maintenance is Needed Resuits Expected When ' Components Maintenance is Performed. i� Extemal: � � Rock Pad Missing or Moved Only one layer of rock exisis above native soil in Replace rocks to design Rock area five square feet or larger,or any exposure of standards. j native soil. . 'i Dispersion Trench Pipe Plugged with Accumulated sediment that exceeds 20%of the Pipe cleaned/flushed so that it � Sediment design depth. matches design. I�� Not Discharging Visuat evidence of water discharging at Trench must be redesigned or � Water Properly concentrated p�ints along trench(normal condition rebuilt to standards. is a"sheet flov�l'of water along trench).Intent is to � prevent erosion damage. � Perforations Over 1!2 of rforations in i e are lu ed with Clean or re lace erforated i e. Pe P P P 99 P P P P Plugged. debris and sediment j Water Flows Out Maintenance person observes water flowing out Facility must be rebuilt or I ' T�p of"Distributo�' during any storm fess than the design storm or its redesigned to standards. Catch Basin. causing or appears likely to cause damage. �I Receiving Area Water in receiving area is causing or has potential No danger of fandslides. I Over-Saturated of causing tandsCde problems. I � i Intemal: � Manhole/Chamber Wom or Damaged Struchtre dissipating flow deteriorates to 1/2 or Replace struciure to design ' Post.Baffles,Side original size or any concentrated wom spot standards. I of Chamber exceeding on2 square foot which would make , structure unsound. '� � Other Defects See"Catch Basins"Standard No.5 See"Catch Basins"Standard No. I' 5 � il II i � ! _..__ _ _ __. ____ _ _ ._ __ _ _ _ _ _. _ _. _ __ _ _ _ . _ 1998 Surface Water Design Manual 9/1i9� A-7 APPENDIX A Iv1AL'�ITEN�\TCE STANDARDS FOR PRNA'F'ELY MAINTAIIv�ED DR�IN?GE FACIL i� S NO.8-FENCING Maintenance Defect Conditions When Maintenance is Needed Results Expected When Components Maintenance is Performed I Generai Missing or Broken Any defect in the fence that permits easy entry Parts in place to provide adequate Parts to a facility. security. � Erosion Erosion more than 4 inches high and 12-18 No opening under the f�nc�that I inches wide permitting an opening under a exceeds 4 inches in height. fence. � Wire Fences Damaged Parts Post out of plumb more than 6 inches. Post plumb to within 1-1!2 inches. Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. , Any part of fence(inciuding post,top rails,and Fence is aligned and meets design fabric)more than 1 foot out of design alignment. standards. Missing or loose tension wire. Tension wire in place and holding fabric. Missing or loose barbed wire that is sagging Barbed wire in place with less than more than 2-1/2 inches between posts. 3/4 inch sag between post. Extension arm missing,broken,or bent out of Extension arm in place with no ' shape more than 1 1/2 inches. bends larger than 3/4 inch. Deteriorated Paint or Part or parts that have a rusting or scaling Structurally adequate posts or Protective Coating condition that has affected structural adequacy. parts with a uniform protective � coating. Openings in Fabric Openings in fabric are such that an 8-inch- No openings in fabric. diameter ball could fit through. NO. 9- GATES Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component , Maintenance is Performed General Damaged or Missing Missing gate or locking devices. Gates and Locking devices in Members place. Broken or missing hinges such that gate cannot Hinges intact and I ubed. Gate is be easily opened and closed by a maintenance woricing freely. person. Gate is out of plumb more than 6 inches and Gate is aligned and vertical. more than 1 foot out of design alignment Missing stretcher bar,stretcher bands,and ties. Stretcher bar,bands and ties in place. Openings in Fabric See`Fencing"Standard No.8 See"Fencing"Standard No. 8 9/1/98 1998 Surface�ti'ater Desisn I�1anua1 A-8 APPENDIX A MAINT�NANCE STAI�IDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACII.I'TIES N0. 10-CONVEYANCE SYSTEMS{PIPES & DtTCHES) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Pipes Sediment&Debris Accumulated sediment that exceeds 20%of the Pipe cleaned of ail sediment diameter of the pipe. and debris. Vegetation Vegetation that reduces free movement of water Ali vegetation removed so water through pipes. flows freely through pipes. Damaged Protective coating is damaged;rust is causing Pipe repaired or replaced. more than 50%deterioration to any part of pipe. I Any dent that decreases the cross section area of Pipe repaired or replaced. I, pipe by more than 20%. I Open Ditches Trash&Debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. I Sediment Accumulated sediment that exceeds 20%of the Ditch cleaned/flushed of all '� design depth. sediment and debris so that it matches design. Vegetation Vegetation that reduces free movement of water Water flows freely through through ditches. ditches. Erosion Damage to See"Ponds"Standard No.1 See"Ponds"Standard No.1 Slopes Rock Lining Out of Maintenance person can see native soil beneath Replace rocks to design Pface or Missing(If the rock lining. standards. Applicable). Catch Basins See"Catch Basins:Standard No.5 See"Catch Basins"Standard No.5 Debris Barriers See"Debris Barriers"Standard No.6 See"Debris Barriers"Standard (e.g.,Trash Rack) No.6 NO. 1� -GROUNDS(LANDSCAPING) Maintenance Defect Conditians When Maintenance is Needed Results Expected When Component " Maintenance is Pertormed General Weeds Weeds growing in more than 20%of the landscaped Weeds present in less than 5% (Nonpoisonous) area(trees and shrubs only). of the landscaped area. 5afety Hazard Any presence of poison ivy or other poisonous No poisonous vegetation vegetation. presentinlandscaped area. Trash or Litter Paper,cans,bottles,totaling more than 1 cubic foot Area clear of litter. � within a landscaped area(trees and shrubs only)of 1,000 square feet. Trees and Shrubs Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than broken which affect more than 25%of the total 5%of total foliage with split or foliage of the tree or shrub. broken limbs. Trees or shrubs that have been blown down or Tree or shrub in place free of knocked over. injury. Trees or shrubs which are not adequately supported Tree or shrub in place and or are leaning over,causing exposure of the roots. adequately supported;remove any dead or diseased trees. 1998 Surface Water Design Manual 9!1/98 A-9 APPENDIX A MAINTENANCE STANDARDS FOR PRNATELY MAINTAINED DRAINAGE FACLITIES NO. 12-ACCESS ROADS/EASEMENTS Maintenance Defect Condition When Maintenance is Needed Results E�ected When Component Maintenance is PerFormed General Trash and Debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway free of det '� �.` square feet i.e.,trash and debris would fill up could damage tires. one standards size garbage can. Blodced Roadway Debris which could damage vehicie tires(glass Roadway free of debris wi�. or metal). could damage tires. My obstruction which reduces dearance above Roadway overhead clear tc . road surface to less than 14 feet high. Any obstruction resUicting the access to a 10 to Obstruction removed to atlow at 12 foot width for a dstance of more than 12 feet least a 12 foot access. or any point restricting access to less than a 10 foot width. Road Surface Settlement,Potholes, When any surface defect exceeds 6 inches in Road surface uniformty smooth Mush Spots,Ruts depth and 6 square feet in area In general,any with no evidence of settlement, surface defect which hinders or prevents potholes,mush spots,or n�ts. maintenance access. � Vegetation in Road Weeds growing in the road surface that are Road surface free of weeds taller � SurFace more than 6 inches tall and less than 6 inches than 2 inches. , tall and less than 6 inches apart within a 400- square foot area. Modular Grid Build-up of sediment mildly contaminated with Removal of sediment and disp�: Pavement petroleum hydrocarbons. in keeping with Health Departme recommendations for mildly contaminated soils or catch basi sediments. �I Shoulders and Erosion Damage Erosion within 1 foot of the roadway more than 8 Shoulder free of erosion and ' Ditches inches wide and 6 inches deep. matching the surrounding road. Weeds and Brush Weeds and brush exceed 18 inches in height or Weeds and brush cut to 2 inche� hinder maintenance access. in height or cleared in such a wa as to allow maintenance access. 9/7/9R ]99R Serface«ater DeeiRr.�1�- APPENDIX A STORMWATER POLLUTION PREVENTION PLAN i � � , �--; I , �2013 D. R.STRONG Consulting Engineers Inc. Piper's Bluff Plat Page 43 of 43 Drainage Report City of Renton STORIVIWATER POLLUTION PREVENTION PLAN For PIPER'S BLUFF Prepared For WestPac Development, LLC 7449 W Mercer Way Mercer Island, WA 98040 206-619-2992 Owner Developer Operator/Contractor WestPac Development, LLC WestPac Development, LLC WestPac Development, LLC 7449 W Mercer Wa 7449 W Mercer Wa 7449 W Mercer Wa Mercer Island, WA 98040 Mercer Island, WA 98040 Mercer Island, WA 98040 Project Site Location 1166 Hoquiam Ave NE, Lynnwood, Washington Certified Erosion and Sediment Control Lead Peter O'Kane 206-619-2992 SWPPP Prepared By D.R. Strong Consulting Engineers, Inc. 10604 NE 38th Place, Suite 101 Kirkland, Washington 98033 Luay R. Joudeh, P.E.,Project Engineer SWPPP Preparation Date January 31, 2012 Approximate Project Construction Dates April 2013 O 2012 D.R.STRONG Consulting Engineers Inc. _--,i STORMWATER POLLUTION PREVENTION PLAN TABLE OF CONTENTS 1. INTRODUCTION .........................................................................................................1 2. SITE DESCRIPTION ...................................................................................................3 2.1 Existing Conditions.........................................................................................3 2.2 Proposed Construction Activities..................................................................3 3. CONSTRUCTION STORMWATER BMPS..................................................................5 3.1 The 12 BMP Elements .....................................................................................5 3.1.1 Element #1 — Mark C�earing Limits.............................................................5 3.1.2 Element#2 — Establish Construction Access .............................................5 3.1.3 Element#3 — Control Flow Rates...............................................................6 3.1.4 Element#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 .................................................................10 3.1.12 Element#12 — Manage the Project ..........................................................11 3.2 Site Specific BMPs ........................................................................................13 3.3 Additional Advanced BMPs..........................................................................13 4.0 CONSTRUCTION PHASING AND BMP IMPLEMENTATION................................14 5.0 POLLUTION PREVENTION TEAM.........................................................................15 5.1 Roles and Responsibilities...........................................................................15 5.2 Team Members ..............................................................................................15 6.0 SITE INSPECTIONS AND MONITORING...............................................................16 6.1 Site Inspection...............................................................................................16 6.1.1 Site Inspection Frequency........................................................................16 6.1.2 Site Inspection Documentation.................................................................16 6.2 Stormwater Quality Monitoring ....................................................................17 6.2.1 Turbidity Sampling .........................................................................................17 6.2.2 pH Sampling ..................................................................................................18 6.2.3 Temperature Monitoring ...........................................................................18 7.0 REPORTING AND RECORDKEEPING ..................................................................19 7.1 Recordkeeping...............................................................................................19 7.1.1 Site Log Book...........................................................................................19 7.1.2 Records Retention....................................................................................19 7.1.3 Access to Plans and Records...................................................................19 7.1.4 Updating the SWPPP...............................................................................19 I O 2013 D. R. STRONG Consulting Engineers Inc. Page i of ii I Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 7.2 Reporting .......................................................................................................19 7.2.1 Discharge Monitoring Reports..................................................................19 7.2.2 Notification of Noncompliance..................................................................20 7.2.3 Permit Application and Changes ..............................................................20 Appendices AppendixA— Site Plans ................................................................................................21 Appendix B — Construction BMPs..................................................................................22 Appendix C —Alternative BMPs.....................................................................................23 Appendix D — General Permit........................................................................................24 Appendix E— Site Inspection Forms (And Site Log)......................................................25 Appendix F — Engineering Calculations.........................................................................32 Appendix A Site Plans • Site plan with TESC measures Appendix B Construction BMPs • Possibly reference in BMPs, but likely it will be a consolidated list so that the applicant can photocopy from the list from the SWMM. Appendix C Alternative Construction BMP list • List of BMPs not selected, but can be referenced if needed in each of the 12 elements Appendix D General Permit Appendix E Site Log and Inspection Forms Appendix F Engineering Calculations • Flows, ponds, etc... �2013 D. R. STRONG Consulting Engineers Inc. Page ii of ii Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan 1. INTRODUCTION This Stormwater Pollution Prevention Plan (SWPPP) has been prepared as part of the NPDES stormwater permit requirements for the Piper's Bluff residential subdivision �I project located at 1166 Hoquiam Ave NE, in Renton, Washington. The existing Site is '� approximately 217,369 s.f. (4.990 ac). Total proposed Project area is 216,966 s.f. (4.981 ac), which includes 10,337 s.f. (0.237 ac) for the right-of-way frontage improvements on Hoquiam Avenue NE and excludes 10,740 s.f. (0.247 ac) of Tract "B" (NGPA). The proposed development is the subdivision of the Site into 28 single-family residential lots, with the associated infrastructure consisting of road frontage improvements, plat access road, storm drainage conveyance system, detention and water quality treatment facilities, water and sanitary sewer main extensions and sewer lift station. Construction activities will include, grading, roadway construction, utility installation and home construction. The purpose of this SWPPP is to describe the proposed construction activities and all temporary and permanent erosion and sediment control (TESC) measures, pollution prevention measures, inspection/monitoring activities, and record keeping 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 beneficial uses of the receiving water by controlling peak flow rates and volumes of stormwater runoff at the Permittee's outfalls and downstream of the outfalls. This SWPPP was prepared using the Ecology SWPPP Template downloaded from the Ecology website on March 20, 2012. This SWPPP was prepared based on the requirements set forth in the Construction Stormwater General Permit, Stormwater Management Manual for Western Washington (SWMMWW 2005). The report is divided into seven main sections with several appendices that include stormwater related reference materials. The topics presented in the each of the main sections are: • Section 1 — INTRODUCTION. This section provides a summary description of the project, and the organization of the SWPPP document. • Section 2 — SITE DESCRIPTION. This section provides a detailed description of the existing site conditions, proposed construction activities, and calculated stormwater flow rates for existing conditions and post— construction conditions. • Section 3 — CONSTRUCTION BMPs. This section provides a detailed description of the BMPs to be implemented based on the 12 required elements of the SWPPP (SWMMEW 2004). ��.2013 D. R. STRONG Consulting Engineers Inc. Page 1 of 39 Stormwater Poliution Prevention Plan Piper's Bluff January°,t 2012 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 control inspector • Section 6 — INSPECTION AND MONITORING. This section provides a description of the inspection and monitoring 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 — RECORDKEEPWG. This section describes the requirements I 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 Construction BMP list Appendix D — General Permit Appendix E — Site Log and Inspection Forms Appendix F — Engineering Calculations O 2013 D. R.STRONG Consufting Engineers Inc. Page 2 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31, 2012 Stormwater Pollution Prevention Plan 2. SITE DESCRIPTION 2.1 Existing Conditions The Site is 4.990 acres in size. It contains two single-family residences, three out buildings and gravel driveway. The remainder of the Site is lawn, landscaping, heavily vegetated with native grasses and shrubs, scatter trees, berry bushes and moderately dense forest and underbrush. There is a Category 2 Wetland and a Class 4 Stream located near the northeast property corner. Site runoff travels northeasterly and enters a Category 2 Wetland located near the northeast property corner and then exits to north via Class 4 Stream. The Site topography slopes generally to the east and northeast at approximately 2 to 15%. A review of the SCS soils map for the area (see Figure 4, Soils) indicates Alderwood gravelly sandy loam with 6 to 15 percent slopes (AgC) and Alderwood gravelly sandy loam with 15 to 30 percent slopes (AgD). Per the Manual, this soil type is classified as "Till" material. 2.2 Proposed Construction Activities The applicant is seeking approval to subdivide the Site into 28 single-family residential lots through the City of Renton subdivision process. All surface water runoff from Site pollution generating impervious surfaces (roads, driveways and frontage improvement on Hoquiam Ave) will be collected in a series of catch basins and pipes and conveyed to the detention and water quality treatment facilities. The following summarizes details regarding Site areas: • Total Site area: 4.990 ac. • Total Project area: 4.981 ac. • Percent impervious area before construction: 5.5 % • Percent impervious area after construction: 63.6 % • Disturbed area during construction: 4.981 ac. • Disturbed area that is characterized as impervious (i.e., access roads, staging, parking): 1.00 ac. I • 2-year stormwater runoff peak flow prior to construction (existing): 0.173 cfs • 10-year stormwater runoff peak flow prior to construction (existing): 0.289 cfs • 2-year stormwater runoff peak flow during construction: 0.414 cfs • 10-year stormwater runoff peak flow during construction: 0.624 cfs • 2-year stormwater runoff peak flow after construction: 0.930 cfs O 2013 D. R.STRONG Consulting Engineers Inc. Page 3 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan • 10-year stormwater runoff peak flow after construction: 1.880 cfs O 2013 D. R. STRONG Consulting Engineers Inc. Page 4 of 39 , Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan '� 3. CONSTRUCTION STORMWATER BMPS '� 3.1 The 12 BMP Elements 3.1.1 Element#1 — Mark Clearing Limits 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. Trees that are to be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated, both in the field and on the plans. In general, natural vegetation and native topsoil shall be retained in an undisturbed state to the maximum extent possible. The BMPs relevant to marking the clearing limits that will be applied for this project include: • Preserving Natural Vegetation (BMP C101) • High Visibility Plastic or Metal Fence (BMP C103) High-visibility orange plastic construction fencing will mark the clearing limits and trees to be retained. 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 abo�e 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 alternative 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, and wheel washing, 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: • Stabilized Construction Entrance (BMP C105) • Construction Road/Parking Area Stabilization (BMP C107) A Stabilized Construction Entrance will be installed south of the existing residence's southwest corner, along the street frontage. This will allow construction equipment access around the west and north sides of the structure. The existing paved driveway will be utilized for parking for three vehicles, as well as construction equipment and material staging. 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 O 2013 D. R. STRONG Consulting Engineers Inc. Page 5 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan 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 alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 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. The specific BMPs for flow control that shall be used on this project include: • No BMPs to be implemented An Alternative BMP includes straw wattles and silt fencing down slope of disturbed areas. The Project is unlikely to result in downstream erosion, due to minimal Site grading, and construction runoff will not drain to a combined sewer system. Alternate flow 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 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. 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 erosion, or where necessary to meet local agency stormwater discharge requirements (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 an infiltration facility. The specific BMPs to be used for controlling sediment on this project include: • Straw Bale Barrier (BMP C230) • Silt Fence (BMP C233) • Straw Wattles (BMP C235) • Storm Drain Inlet Protection (BMP C220) Silt fencing and/or straw wattles will be installed down slope of disturbed areas. Storm drain filter socks will be installed in the four catch basins adjacent to the Site on the Ridge Road and 84th Ave NE frontages. O 2013 D. R.STRONG Consulting Engineers Inc. Page 6 of 39 �..,.�,. ,f :. �,_�� ,.__ �-;..,,. .,.. �i,., �. ..�; ��°� :. i��,� ,� �� -, , � Stormwater Pollution Prevention Plan Alternate sediment 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 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. In addition, sediment will be removed from paved areas in and adjacent to construction work areas manually or using mechanical sweepers, as needed, to I� minimize tracking of sediments on vehicle tires away from the Site and to minimize washoff of sediments from adjacent streets in runoff. 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 loads 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 detention 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 j BMPs. Any accumulated sediment shall be removed after construction is complete and the permanent stormwater BMP will be restabilized with vegetation per applicable design requirements once the remainder of the Site has been stabilized. The following BMPs will be implemented as end-of-pipe sediment controls as � required 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 Pond (BMP C241) • 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) O 2013 D. R.STRONG Consulting Engineers Inc. Page 7 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan Dust Control (BMP C140) Mulching will be implemented on exposed soils as necessary for temporary stabilization during construction. Permanent seeding and planting will stabilize disturbed areas upon Project completion. 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 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 alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. _ In general, cut and fill slopes will be stabilized as soon as possible and soil stockpiles will be temporarily covered with plastic sheeting. All stockpiled soils shall be stabilized from erosion, protected with sediment trapping measures, and where possible, be located away from storm drain inlets, waterways, and drainage channels. 3.1.6 Element#6 — Protect Slopes All cut and fill slopes will be designed, 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 C120) • Straw Wattles (BMP C235) Slope grading is confined to small areas to the east of the driveway, and southwest and northwest of the residence. Grade changes are in the range of one to two feet of cut or fill. Retaining walls are proposed west of the residence in conjunction with a new walk-out patio from the basement. Straw wattles will provide temporary slope stabilization. Permanent seeding and planting will be implemented after Project completion. Alternate slope protection 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 alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.7 Element#7 — Protect Drain Inlets All storm drain inlets and culverts made operable during construction shall be protected to prevent unfiltered or untreated water from entering the drainage O 2013 D.R.STRONG Consufting Engineers Inc. Page 8 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Poilution Prevention Plan conveyance system. However, the first priority is to keep all access roads clean of sediment and keep street wash water separate from entering storm drains until treatment can be provided. Storm Drain Inlet Protection (BMP C220) will be implemented for all drainage inlets and culverts that could potentially be impacted by sediment-laden runoff on and near the project Site. The following inlet protection measures will be applied on this project: • Drop Inlet Protection o Catch Basin Filter 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 Control 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 or 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: , • No BMPs to be implemented o No temporary or permanent channels or outlets are proposed. Alternate channel and outlet 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 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 alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.9 Element#9 — Control Pollutants All pollutants, including waste materials and demolition debris, that occur onSite shall be handled and disposed of in a manner that does not 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 to be implemented to control specific sources of pollutants are discussed bel�w. • Vehicles, construction equipment, and/or petroleum product storage/dispensing: o All vehicles, equipment, and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks or spills. O 2013 D.R. STRONG ConsuRing Engineers Inc. Page 9 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan �i o On-Site fueling tanks and petroleum product storage containers shall � , include secondary containment. I ; ' � o Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. � o In order to perForm emergency repairs on Site, temporary plastic will be placed beneath and, if raining, over the vehicle. o Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. • Demolition: o Dust released from demolished sidewalks, buildings, or structures will be controlled using Dust Control measures (BMP C140). o 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). o 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 Pollution Prevention measures � (BMP C152). , • Concrete and grout: o 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). The facility does not require a Spill Prevention, Control, and Countermeasure (SPCC) Plan under the Federal regulations of the Clean Water Act (CWA}. 3.1.10 Element#10 — Control Dewatering There will be no dewatering as part of this construction project. 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 BMPs specifications (attached). Visual monitoring of the BMPs will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater 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. �2013 D. R.STRONG Consulting Engineers Inc. Page 10 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan 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 runoff 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: As this project Site is located west of the Cascade Mountain Crest, the project will be managed according to the following key project components: ' • Phasing of Construction o The construction project is being phased to the extent practicable in order to prevent soil erosion, and, to the maximum extent possible, the transport of sediment from the Site during construction. o 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 o 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 � o Limitations on activities and the extent of disturbed areas; and o Proposed erosion and sediment control measures. � o 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: I � 2013 D. R. STRONG Consulting Engineers Inc. Page 1 1 of 39 � S,ormae�ater Pollutlon Prevention Plan Piper's Bluff January 31, 2012 Stormwater Pollution Prevention Plan o Routine maintenance and necessary repair of erosion and sediment control BMPs; o 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 of surface water runoff -- within the Site in approved and installed erosion and sediment control facilities. • Coordination with Utilities and Other Jurisdictions o Care has been taken to coordinate with utilities, other construction projects, and the local jurisdiction in preparing this SWPPP and scheduling the construction work. • Inspection and Monitoring o All BMPs shall be inspected, maintained, and repaired as needed to assure continued performance of their intended function. Site inspections shall be conducted by a person who is knowledgeable in the principles and practices of erosion and sediment control. This person has the necessary skills to: o Assess the Site conditions and construction activities that could impact the quality of stormwater, and o Assess the effectiveness of erosion and sedimen : ; used to control the quality of stormwater discharges o A Certified Erosion and Sediment Control Lead shaii be on-5ite or , call at all times. o Whenever inspection and/or monitoring reveals that the BMPs identified in this SWPPP are inadequate, due to the actual discharge of � or potential to discharge a significant amount of any pollutant, appropriate BMPs or design changes shall be imple��ented as soon as possible. • Maintaining an Updated Construction SWPPP o This SWPPP shall be retained on-Site or within reasonable access to the Site. o The SWPPP shall be modified whenever there is a change in the design, construction, operation, or maintenance at the construction Site that has, or could have, a significant effect on the discharge of pollutants to waters of the state. o The SWPPP shall be modified if, during inspections or investigations conducted by the owner/operator, or the applicable local or state regulatory authority, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater � 2013 D. R. STRONG Consulting Engineers Inc. Page 12 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 I Stormwater Pollution Prevention Plan discharges from the Site. The SWPPP shall be modified as necessary to include additional or modified BMPs designed to correct problems , identified. Revisions to the SWPPP shall be completed within seven I (7) days following the inspection. --- o 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 I control issues that may cause a violation(s) of the NPDES ; Construction Stormwater permit (as provided in Appendix D), the I 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. , 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. 3.3 Additional Advanced BMPs � ,i ,I � O 2013 D.R.STRONG Consulting Engineers Inc. Page 13 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan 4.0 CONSTRUCTION PHASING AND BMP IMPLEMENTATION The BMP implementation schedule will be driven by the construction schedule. The following provides a sequential 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: 4/1/13 • Estimate of Construction finish date: 12/1/13 • Mobilize equipment on site: 4/1/13 • Mobilize and store all ESC and soil stabilization products: 4/1/13 I • Install ESC measures: 4/1/13 � • Install stabilized construction entrance: 4/1/13 • Begin clearing and grubbing: 4/1/13 • Demolish existing buildings: 4/1/13—4/26/12 • Begin Site Grading: 4/8/13 • End Site Grading 9/9/13 • Begin Utility Construction 9/9/13 • End Utility Construction 9/27/13 • Begin implementing soil stabilization and sediment control BMPs throughout the site: 4/8/13 • Final landscaping and planting begins: 9/9/13 • Permanent erosion control measures (hydroseeding): 10/1/13 � 2013 D. R. STRONG Consulting Engineers Inc. Page 14 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 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: • Certified Erosion and Sediment Control Lead (CESCL) — primary 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 project's supervising 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 • 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 Lead. 5.2 Team IUlembers 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 TBD Lead(CESCL) Resident Engineer N/A Emergency Ecology Contact NW Regional Office 425.649.7000 Emergency Owner Contact TBD Non-Emergency Ecology Contact TBD Monitoring Personnel TBD O 2013 D.R. STRONG Consulting Engineers Inc. Page 15 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan 6.0 SITE INSPECTIONS AND MONITORING Monitoring includes 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 log 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 Control Lead (CESCL) per BMP C160. Th� n�mA �n�± /�nnf�r} �„f�,r,,,at;,,n f,-. the CESCL is provided in Section 5 of this SWPPP Site inspection will occur in all areas disturbed . 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 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 documented in the SWPPP as soon as possible. 6.1.1 Site Inspection Frequency I Site inspections will be conducted at least once a week and within 24 hours following ' any discharge 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 request to Ecology or the local jurisdiction. r-� O 2013 D.R. STRONG Consufting Engineers Inc. Page 16 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 _ � Stormwater Pollution Prevention Plan 6.2 Stormwater Quality Monitoring � 6.2.1 Turbidity Sampling �' Monitoring requirements for the proposed project will include either turbidity or water ' � transparency sampling to monitor site discharges for water quality compliance with the 2005 Construction Stormwater General Permit (Appendix D). Sampling will be , conducted at all discharge points at least once per calendar week. '�� Turbidity or transparency monitoring will follow the analytical methodologies described in Section S4 of the 2005 Construction Stormwater General Permit (Appendix D). The 'i , key benchmark values that require action are 25 NTU for turbidity (equivalent to 32 cm I 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. Ensure 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 �i 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 value. Additional treatment BMPs to be considered will include, but are not limited to, off-site treatment, infiltration, filtration and chemical treatment. 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 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. O 2013 D. R. STRONG Consulting Engineers Inc. Page 17 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan 6.2.2 pH Sampling Stormwater runoff wiil 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. I 2. Adjust or neutralize the high pH water if necessary using appropriate �', technology such as CO2 sparging (liquid or dry ice). ' 3. Contact Ecology if chemical treatment other than CO2 sparging is planned. I Describe inspection results and remedial actions that are taken in the site log book and I in monthly discharge monitoring reports as described in Section 7.0 of this SWPPP. � 6.2.3 Temperature Monitoring � No temperature monitoring is required for this construction site. ; � ; � �I i � I i IIStormwater Pollution Prevention Plan � Piper's Bluff January 31,2012 f 1 Stormwater Pollution Prevention Plan , 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 the implementation of the SWPPP and other permit requirements; � • Site inspections; and, • Stormwater quality monitoring. For con�enience, the inspection form and water quality monitoring forms included in this ' SWPPP include the required information for the site log book. 7.1.2 Records Retention Records of all monitoring information (site log book, inspection reports/checklists, etc.), this Stormwater Pollution Prevention Plan, and any other documentation of compliance with permit requirements will be retained during the life of the construction project and for a minimum of three years following the termination of permit coverage in accordance with permit condition SS.C. 7.1.3 Access to Plans and Records The SWPPP, General Permit, Notice of Authorization letter, and Site Log Book will be retained on site or within reasonable access to the site and will be made immediately available upon request to Ecology or the local jurisdiction. A copy of this SWPPP will be provided to Ecology within 14 days of receipt of a written 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 to the SWPPP will be provided to the public when requested in writing in accordance with permit condition S5.G. 7.1.4 Updating the SWPPP In accordance with Conditions S3, S4.B, and S9.B.3 of the General Permit, this SWPPP will be modified if the SWPPP is ineffective in eliminating or 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 potential for discharge, of pollutants 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 problems identified, and an updated timeline for BMP implementation will be prepared. 7.2 Reporting 7.2.1 Discharge Monitoring Reports If cumulative soil disturbance is 5 acres or larger: Discharge Monitoring Reports (DMRs) will be submitted to Ecotogy monthly. If there was no discharge during a given O 2013 D. R.STRONG Consulting Engineers Inc. Page 19 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan monitoring period, the Permittee shall submit the form as required, with the words "No ' discharge" entered in the place of monitoring results. The DMR due date is 15 days ', following the end of each month. I, 7.2.2 Notification of Noncompliance ' 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 I permit section SS.F: ' 1. Ecology will be immediately notified of 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. 'I Any time turbidity sampling indicates turbidity is 250 nephelometric turbidity units (NTU) �I or greater or water transparency is 6 centimeters or less, the Ecology regional office will be notified by phone within 24 hours of analysis as required by permit condition S5.A ;, (see Section 5.0 of this SWPPP for contact information). j In accordance with permit condition S4.F.6.b, the Ecology regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water (see Section 5.0 of this SWPPP for contact information). 7.2.3 Permit Application and Changes In accordance with permit condition S2.A, a complete application form will be submitted to Ecology and the appropriate local jurisdiction (if applicable) to be covered by the General Permit. O 2013 D. R.STRONG Consulting Engineers Inc. Page 20 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 Stormwater Pollution Prevention Plan APPENDIX A - SITE PLANS ,�-- , ' � � �-- , II I � , � , � �_.., ! � � I I �_; I � i ', � (_ , � � (_ ; O 2013 D.R.STRONG Consulting Engineers Inc. Page 21 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2012 ► _ NE 1/4 SEC 170N 10, TOWNSH/P 23 N, RANGE 5 E, W.M. PIPER`S BL UFF LEGEND: :�. Fa�wm waNxrtNr�s r+ortn . .-. FIXINO CQPNfR AS N07E0 ,.. I i � ' :"' , . � i ' I -:__� . . � .: -,- ROAOSICNAGE - j ..� %� �:'-_ �.. .., �. .��- - . . .. j - . YAltD LlNT � `� I �—� � .. � ._i , 4:,.., _ _.. ( -� PoMER POCE +_ � ,.-:. i .. ._ , , ,.� z .__ . . . - . .' i ... . . ' . � _ - ' , , ' . � ... FM£HYWlANT . i- _ _ . .- - . _ ; � . .. . ._ . . . � A V � � - _ ,- ,� o _ _ . z� ��, F�r s.""'.c r � �, I�_ w me uE� , . `- - - �_ . <s 6 ,. �h _ _�� ROAD A .d . . . ___o _, ar .f .. ��` � rewir.�nav cor+ma v,�� s � ' �� -- _ _ ' l cnrai ensN w � .� : . • . . .. , ,,., . . ; , _ � - ,�^• F .ti o �� Z � � , _ y& � : - -� �� . ..,� . ._,... . _ _�_. . .._ . •___.. - ... -_I ry I �i. .. . � " TARY S£NER MANNp£ ♦� � ; , . . � _. �. ��. I - . . . . .�:�. .._._ .. :1� - ' . � WS 1/ETER . O. ., r— — ' — ..� , _ _ . � . ., ..: . : . _ � � I = � — — -- , \ . w m t �I3200 r----�^�- � - - �-. . .---- . r—' —.. -- -� �_�._ _ _ _'s�^ - - ... YAH011pf7 -� t � . , MA)ERGL SiL14AGE _ ' � i : '. �-AMO QGW57R1/CAGW � .. ... . E-IJi �.� � a i - � � � � STAONG AR£A 1 '.. _ . ��. � � . •. . AEfiDUWS 1RfE UJ i (C01ER F.�PO4D ml� - :.�.__ s.��. �Tf.)PORMY GLlKRT' � \ . �-. _ ,. . . � .__. : � INnW?4/Ot5) 1 jQ .. ":": �� z-•e s-zaoz..,, ��n.fz �� \ �' L r� � r _ L------l.� �[y^ ti I .' - , " EYt7PGRF£N 1R£E w :' .. - , ' � .'' � � 4I --. i:..'�, J` .��, '`v ..�.6 '� o�� J .. 8��:._ . � . �� ,,� -.� �4 s � � . � - �- 2- 3 ' � i � : -, . �TRACT B� . . , o� ncTwra ruc!�-�) � _ -- . . � � � _ _ � .^-- ' Mf:PA . v�i i . - ' • - � + ___' • - � �� 1 s2a I . �.� - ROGXERY '�� . ' �� .::', i . —a SMOTARY SEMER L/NE _ ' � ��. .� � I � � ... ,� �-_.-.'._ .'� '-' _ ., -;�'.`` . . .--',� - �.' . . i ' • 1�1�2Y�� Y �� . -.._ � . ' : ,. .. �'.•:. � .... .- . ..1 , r ��' �GS� ; , , .. .,� _ � ... . . ._,. ...� \ .. c � , , � , _ . -..,- . .. —s STGVM UNE _ ' � s ' ' _ __ �I �f19 '�'� ,:`� � ` `� � : 6,� ,: ...• .. .; . , .. �r `- `• . 'c� . , �_ _. : . �.� . �� 4 �/.��.�� b , , . �r ��' . i�:. .). � • . �..: � . -. —r— MGTER LINE � �. � ��. y� �.. . , . � �- � ... t, . .. i ' .,..� sh� ._- , .... . '•••.- • �*� �'`� a}2 '...�_. r :_:.. —•. GAS[N+E + . _. o -.�.. �' ' \ " . . . 4� ry 2 �,�� • Q �' 11� e- . =�— < i � �.. . _ -�� .. 9 Y ` � . —rs OYfRHEAO PoxER I � O r ; , , . .. :,.,. =-.. .' — . - - %� - a O Ul!(!TY � . ALLEY'4 ��T � i , , ... ;,- _ . � � s�-i� � — -- �+r�o -z�-ssz 00 � � � . ` :.... �.-• . r �: � . . . - ..:�. ,.. 43f. . �,._W ' �' ��? ' ' :: . ' , . � . . . �.--:.. _ .�..•...- _ ' mCE CY PAL£LEN7 •� I i' 2.'- 62 . �: �. .� � �• I, ... � � _. . - .._ FENCE • _--`�- • ,I.j J _' -. '.'�' � �'..' _ ."___ .. �O "_ _ ' _ - '� ... _ 446 E_� <76I .._: ___ - :':: '- `. . 45S ' .. � �' � ' . • - W � �.._�< � '..« ` .r.._ c 152 � � MB� ._-. � . • F1•l_ �� . / •- -.. _ . -� � �� '� :.,:,.� �� T � �., �I e ' � � � i.: � 17� ° � ; : ��' ' , � « _> :�_ HB yg�.. 61li 1T% °39 � �i . -. . ...._____— .�,�r. LEGEND: Q i sez �sz +eo ' sss :s� s-aeAs � I '� `I o - aso ' ` ,se j Q -I,� I ��f��.; � 14 � J3 .se 12 ,s, ' 10 , , -._ :-.� , � '. ; �, � J . , ' -g� �, " _ .. '� ,4�`.: <so awsneucnav uuns • •' — =- _ ' -. , ,i,� - �� - �� ,..C?J -__ � - - ' � � - _'�� . T Q.;'_ ��_, � �.. . ... -,I ,�y� - -/ _ M R�NFO?CED 9LT FENCE �. �'__ — — S,�' � ,-=... i ,.t�/ � —J (}�� f - . .-.: — — '.-- .. •� i_, �� ' a . .- �. � .. - _ ' � . . I � ._ � . i51 ' FENLE . ., _ � .. ... -.:�... • - �. .- . . .. .�..' - ��+ K.Y�V� ' '�� m - . �ff LI4ANCf LYWS7RUCALri I � — -� - o�� - . . . . . . . . , �_�_ : . . . .. . I ' ' • � ' ' - T CON 7R!/CT1QV EHTRAN[� . '. , ..,.. .�� , � . ,�... ., , .:, .. , � . _ /. . I ., � �_ . • .. . . ' '. 1"- -'. _ _ , �.., . , ., � . . _ _ s� � � �j� �� 5 A8MlgD 5 � L ov °�° ROAD A' ! 1 � p � s : ` �r : �, :•,�• : �� e � - , o_ 9 .. � ot�._ ' � � , � � ,. • CT D ousrcavsra _ T �� i � 1 , -- j . � �\ ( .. A � �� . . �� MUCGONG MAT7INC.k CQVPo57 BUNNE75 �. . " ' '+_ .'� _'� ...— ^ 155 1.�.• .-. 1 �.. 9� pRGopgD �/�riT C■ . O WLE7 PR01EC7KW .'� = •_ ��_ _ — � O - �`.-� 1 ; ,. �,�� „��,.��. � �,,,�,�T�,�,�� ; 1£R; �� E �J'v= .. � _. Y[..._.�-�_L.�._. � . 1 ��_ . .I&f 1.'�/ � �.. �� S7REET SNEEPINC a VALTN1oNC � .. . i. �� - ' � �._ , . c � I , � d 18! '� ; -sa.n � ...—� a,r'�o,w c�r so n�rroac `' � rg�- 20 21 � � I I v �{r._ .' - - 24 � iz'�waar�aran�rrr � � "r�wmu�t srowr�� ' 25 2B ^ f*r 27,, 28 �., z � � ��.. � � �� AHD CCW57RUL77LM � . ' _`. . . - IREE PROlECl10N FDJ�(TREE 70 BE R£TA/NED) � STAGHG AR£A � '�. . f,':,. � � Z i� . �cac�. �:_-- �leti�r�twvsm sw.� . � �,_ .- - � .. met ro er aFwo� ; _ -' s.r, m . `'.� (--�- � ' ' L M7hW S4 FiPS) J :; � _ � � . -__ _ � .: , . . . ..*� - � —•. __ . • � _... . - ---- �a � ,�; �. DEMOUAON NOTES: �_ -� 1 - : -- -_ . , <�,- ' '. . , . ��4 . ' ."" '- . _ - .. . . ' �. -�"� .�..�, v _- . .__. _____ ' _ . . .- ' ;' �-t.��.��. . �62-- ' �' : ' - - � . �. ' . _ _ � ;. �.. �' _ _'__.. .-_ - _ _ � O R£YOl£EM57M�G STFUCTURE ._.•,1" ' �.« ... . ". _—__�. . . a).� . _ 4 �SB f� �32 +�g . N6 . 1 _ _` �_ O RENOVF£#S7AVG MFE fFNC£AND CQVC.PoST . I� `..�� . • . ' OJ RE]VOt£E]OSIAVG 57�dU fI£1rtNT _ � I '�� ....._ � . . � . � . ,. O RE11/OYE O057AYG NA2BOXES ; . ' . -. ._. .. , , � . . : i �'. : ..__�_- ' O RELOGATE F.1TS17NG AOMER Pp.E 1N THf PUNIFR STR/P . . ....... .... ...._ . 3 CONSTRUC770N SEQUENCE.• EROSION CONTROL SEED MIXTURE.• QQ ��TF�SAItG FIRE HKXUNT M THE PLANlER STR1P c fi)coavow��rmoc�rn+c a�Ea7srvrc unur�s nu�cav.n�cr wn��sc vc,ws O REMOI£OOSTWG WA 7ER YE7ER (2)vac-ecwsmucna+ueFnr�c ecr�N cavrn�crzw tivo n,�arr s�e nasrreroe wenu+cs cw rrm rrscue � Oe aEvo�oosrwc«x��arrr�xwnr 8 (Jf FLAC 014 FDNC£CL£ARING L!W 75 ANNUA!LIR PERENN/AL RYE IO R (1)PQSI SGV INTN NAVE AND PHQYE MN�fR 01�SNPPP CQpPDA1A7pP. R£D7CP pP COLQY/AL BENICRASS ]0 O RENOY£EA75TlNG GRAYEL p4/l£WAY - (5)CRAOE AND INSTA(L LCWSIRfICTiON£NTRANCE NHl7E WTCN CYOH_F 70 (6J INSTA(L PER1Mf7ER PRO7FCTi�'J. � (7)COR�57RUCT PER4lANENT 57P2NWA7FR OEIENTiQV PPVD PRKK 10 CLEARINC h(iPAOINC CQVSIR!/CT PfR STL14M ORAIN.IGE AND 57RUCTURAL PUNS SP£Gf1CAMX15 PLUG PQVD WILET,PUNP AS NECESSARY TO AKYO Ol£RfLOMC SEDMIENT UDEN WATER 9YALl B£OISPOS£'D p�lN A ' MANN£R MPROY£D BY THE p7Y. � (B)STA8/LlI£CLNlSTRUC7KXf FDAD. Q (v)cavsrnucr n��cwvavarr on,vNat�caicenav,wo cbw�rr�Nc�wmres,wo v�s eeraeE,wo/cw oura,vc s�e cte�rrr�c. Df3AWINCaS NOT APPROVED (!O)NAINiAlN EF09CW CQYiRQL U£ASUR£5 W ACCQRDANCE NIIH GYiY STANOAROS AND YAMIFACTI.Y�EN^S RECQIINENDA770NS `� �n�an ocnre exosav cawrr�ae�w�s oe nasrnu r�cw we�sraes so rrur,�s s�e conmrnavs ar,we,� nff txo9ar aro sarwcvr FOR CONSTRUCTION UNLESS RECOMMENDED � ��,s�.wan.��,�»��,�on,�W�,��N� N O RT H (1YJ COl£R ALL ARfAS 7HAT Nf11 BE UNNLY2KfD FCR Yp4F)NAN$[LfN DAYS pA2qY'TNE ORY g./5Q4 C14 TM7 DAYS OURINC 7HE NE1 SEASLW FOR APPROVAL € �n�srn�w, koao�rr Mu�w,couAosr,pusnc sraErnvG ae raav,�ccn� STAMPED OR SIGNED APPROVED (1JJ STA&UZE ALL ARfAS IHAT R£ACN F1NAC GRALIE M1TWN$EYF/1 DAYS GRAPH'iC SGl+LE BY ��J scEo oa son�wr,we�s 7D R£NAIN WlNQRKEO FdP Y04£THAN JO OAYS o is ao � BY THE REVIEWING AGENCY � (75)UPQN CpAPCE1IQ'I CK THE PR0.ECi,ALL O/SIURBEO AR£AS WSi 8£SiABA1ZE0 AND 9uP5 RElIOI£O IF APPRpW�ATE. � �� BY � 1 INCH=30 FT. �h Py R.JpG BY y t4 ap'�/,�E,F � SR �E�. NO1ID zc.� we'�isiUrn� (3 I �6-28-�2 � D.R. S7RONG CITY OF CN2WorkFgDayeBeloreYouD'p � � cavsucnrvcovarvmes � � 'Y PIPER'S BLUFF � 1-800-424-5555 �y D � �°`"��"°� � REN TON � �� asw�mnPc.not�o.w�a�x, °"""ar� 1 I a� T.E.S.C.PLAN U67tiea1hder�andLocetlonCeMer '`�@si��,� ous.en.ze9P�zs1z7�tf � Ptonning/3uilding/Public Works Dept. � (DMI'DARWAI �ONAI. � su.E,�n„�. G ��7v� �0. REVISI04 BY DATE APPR � �"�°'�t8 A- NNNNAA APPENDIX B - CONSTRUCTION BMPS Preserving Natural Vegetation (BMP C101) , High Visibility Plastic or Metal Fence (BMP C103) Stabilized Construction Entrance (BMP C105) �I ` Wheel Wash (BMP C106) Construction Road/Parking Area Stabilization (BMP C107) Silt Fence (BMP C233) Temporary and Permanent Seeding (BMP C120) Mulching (BMP C121) Dust Control (BMP C140) Storm Drain Inlet Protection (BMP C220) Outlet Protection (BMP C209 f � O 2013 D. R.STRONG Consuking Engineers Inc. Page 22 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2013 —� 4.1 Source Cootrol BMPs BMP C101: Preserving Natural Vegetation Purpose The purpose of presen�ing natural vegetation is to reduce erosion and surface runoff. Conclitions of Use Natural vegetation should be preserved on steep slopes, near perennial and intermittent «�atercourses or s��ales, and on building sites in ��ooded areas. Design and Installation Specifications Fence or clearly mark areas around trees that are to be saved. Where feasible, do not disturb ground within the dripline of trees that are to be saved. Do not place fill of more than six inches depth within the dripline of trees that are to be saved. If roots of plants intended to be saved must be cut due to excavations: • Cut as few roots as possible, and cut them cleanly. • Paint cut root ends with a wood dressing such as asphalt base paint. • Backfill excavations in these areas as soon as possible. i Maintenance Standards Inspect flagged and/or fenced areas regularly to make sure flagging or fencing has not been removed or damaged. If the flagging or fencing has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. If tree roots have been exposed or injured, "prune" cleanly with an appropriate pruning saw or loppers directly above the damaged roots and recover with native soils. Treatment of sap flo��ing trees (fir, hemlock, pine, soft maples) is not advised as sap forms a natural healing barrier. September 2010 Snohomish Counfy Drainage Manua! Volume!I-Construction Stormwater Pollufion Prevenfion 23 BMP C103: High Visibility Plastic or Metal Fence Purpose Fencing is intended to: (1) 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 consh-uction entrances or roads; and, (4)protect areas where inarlcing��ith survey tape may not pcovide adequate protection. Conditions of Use To establish clearing limits,plastic or metal fence may be used: • At the boundary of sensitive areas,their buffers, and other areas required to be left uncleared. . As necessaty to control vehicle access to and on the site. Design and Installation Specifications High visibility plastic fence shall be composed of a high-density polyethylene material and shall be at least four feet in height. Posts for the fencing shall be steel or wood and placed every 6 feet on center(maximum}or as needed to ensure rigidity. The fencing shall be f�stened to the post every six inches with a polyethylene tie. On long continuous lengths of fencing, a tension wire or rope shall be used as a top stringer to pt�event sagging between posts. The fence color shall be high visibility orange. The fence tensile st�•enb h shall be 360 lbs./ft. using the ASTM D4595 testing method. Metal fences shall be designed and installed according to the manufacturer's specifications. Metal fences shall be at least 3 feet high and must be highly visible. Fences shall not be «�ired or stapled to h�ees. Maintenance Standards If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately and �-isibility restored. September 2090 Snohomrsh County Drainage Manual Volume!I- Construcfion Stormwater Pollution Prevention 25 BMP C105: Stabilized Construction Entrance Purpose Construction entrances are stabilized to reduce the ainount of sediment transported onto paved roads by vehicles or equipment by constructing a stabilized pad of quarry spalls at entrances to construction sites. Conditions of Use Construction entrances shall be stabilized wherever traf�c will be leaving a constt�uction site aud tcaveling on paved roads or other paved areas within 1,000 feet of the site. On large commercial,highway,and road projects, the designer should include enough extt•a materials in the contract to allow for additional stabilized ent��ances not shown in the initial SWPPP. It is difficult to determine exactly where access to these projects will take place; additional materials tivill enable the contractor to install them where needed. Design and Installation Specifications See Figure 4.2 for details.Note: the 100' minimum length of the entrance shall be reduced to the maximuin practicable size when the size or configuration of the site does not allow the full length (100'). A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping up into the rock pad. The geotextile shall meet the specifications for moderate survivability set forth in the 2008 WSDOT Standard Specifications, Section 9-33.I Geosynthetic Material Requirements, Table l, and shall meet the Class A AOS specification in Table 2 of that document Consider eacly installation of the first lift of asphalt in areas that will paved; this can be used as a stabilized entrance. Also consider the installation of excess concrete as a stabilized entrance. During large concrete pours, excess concrete is often available for this purpose. Hog fuel (wood-based mulch)may be substituted for or combined with quariy spalls in areas that will not be used for permanent roads. Hog fuel is generally less effective at stabilizing const�uction entcances and should be used only at sites where the amount of traffic is very limited. Hog 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 inay at any time require the use of quai-�•y spalls if the hog fuel is not preventing sediment from being traciced onto pavement or if the hog fuel is being carried onto pavement. Hog fuel is prohibited in permanent roadbeds because organics in the subgrade soils cause degradation of the sub�ade support over time. Fencing(see BN1Ps C103 and C104) shall be installed as necessary to restrict traffic to the construction entrance. Whenever possible, the entcance shall be consh•ucted on a firm, compacted subgrade. This can substantially increase the effectiveness of the pad and reduce the need for maintenance. September 20 i 0 Snohomish Ccur,ty Drainage f✓;anual 1io;ume 11- Constructron Storm�-vater PoNutior�Prever,fion 27 BMP C106: Wheel Wash Purpose Wheel washes reduce the amount of sediment transported onto paved roads by motor vehicles. Conditions of Use When a stabilized construction entrance{see BMP C 105) is not preventing sediment from being tracked onto pavement. Wheel washing is generally an effective BMP when installed with careful attention to topography. For example, a wheel wash can be detrimental if installed at the top of a slope abutting a right-of-way where the water from the dripping truck can run unimpeded into the street. Pressure washing combined with an adequately sized and surfaced pad with direct drainage to a large 10-foot x 10-foot sump can be very effective. Design and Installation Specifications Suggested details are shown in Figure 4.3. Snohomish County may allow other designs. A minimum of 6 inches of asphalt treated base (ATB) over crushed base material or 8 inches over a good subgrade is recommended to pave the wheel wash. Use a low clearance truck to test the wheel wash before paving. Either a belly dump or lowboy will worlc well to test clearance. Keep the water level from 12 to 14 inches deep to avoid damage to trucic hubs and filling the , truck tongues with water. ' Midpoint spray nozzles are only needed in extremely inuddy conditions. Wheel wash systems should be designed with a small grade change, 6 to I2 inches for a 10-foot- wide pond,to allow sediment to flow to the low side of pond to help prevent re-suspension of sediment. A dt•ainpipe with a 2-to 3-foot riser should be installed on the low side of the pond to allow for easy cleaning and refilling. Polymers may be used to profnote coagulation and flocculation in a ciosed-loop system. Polyacrylamide (PAM) added to the wheel wash water at a rate of 0.25 -0.5 pounds per 1,000 gallons of water increases effecti��eness and reduces cleanup time. If PAM is already being used for dust or erosion control and is being applied by a water tc•uck,the same truck can be used to change the wash water. Maintenance Standards The wheel wash should stact out the day with fi�esh water. The wash water should be changed a minimum of once per day. On large earthwork jobs where more than 10-20 trucics per hour are expected, the��vash water��ill need to be changed inore often. Wheel vvash or tire bath t��astewater shall be discharged to a sepat•ate on-site treatment Sepfember2010 Snohomish County Drairage P"'anual Voiume Jl-Construction Stornn^�a'erPollufion Prevenfion 29 system, such as closed-loop recirculation or land application, or to the sanitary sewer with proper local sewer district approval. A "Schedule 40 1 Yz'schedule 40 for sprayers � M � � 2% 5:1 5:1 ( I 2% Slope Slope Slope Slope II 1�1 II SIApe Wheel Wash Plan 15 15 20' 15 50' � � � Elevation View ,Water level �1g ( - 1:1 Slope i � �______.�.i�J Section A-A i N.T.S. ' Figure 4.3 Wheel Wash Notes: I' 1. Asphalt construction entrance 6 in.aspl�alt treated base(ATB), 2. 3-inch trash pump�vitlz floats on die suction hose. 3. Midpoint spray nozzles,if needed. 4. G-inch sewer pipe with butferfly valves. Bottom one is a drain. Locate top pipe's invert 1 foot above bottom of wheel wash. 5. 8 foot x 8 foot sump with 5 feet of catch. Build so can be cleaned with tracld�oe. 6. Asphalt curb on the low road side to direct water back to pond. 7. 6-inch sleeve under road. 8. Ball valves. 9. 15 foot.ATB apron to protect ground from splashing«rater. September 2090 Snohomish County Drainage Manua! Volume 11-Construcfion Stormwater Pollufion Preventron 30 B�ZP C107: Construction Road/Parlcing Area Stabilization Purpose Stabilizing subdivision roads,parlcing areas, and other onsite vehicle transpoi-tation routes ' immediately aftec grading reduces erosion caused by construction traffic or runoff. Conditions of Use Roads o►�parlcing areas shall be stabilized wherever they are constructed,whether permanent or temporary, foi•use by construction tra�c. Fencing(see BMPs C 103 and C 104)shall be installed, if necessary,to limit the access of vehicles to only those roads and parking areas that are stabilized. Design and Installation Specifications On areas that will receive asphalt as pa�-t of the project, install the first lift as soon as possible. A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed surfacing base course shall be applied immediately after grading or utility installation. A 4-inch course of asphalt treated base (ATB)may also be used, or the road/parlcing area may be paved. It may also be possible to use cement or calcium chloride for soil stabilization. If cement or cement kiln dust is used for roadbase stabilization,pH monitoring and BMPs are necessary to evaluate and minimize the effects on stormwater. If the area will not be used for permanent roads,parlcing areas, or structures, a 6-inch depth of hog fuel may also be used, but this is lilcely to require more inaintenance. Whenever possible, construction roads and parking areas shall be placed on a fn-m, compacted subgrade. Temporary road gradients shall not exceed 15 percent. Roadways shall be carefully graded to drain. Drainage ditches shall be provided on each side of the roadway in the case of a crowned section, oi�on one side in the case of a super-elevated section. Drainage ditches shall be directed to a sediment control BMP. Rather than relying on ditches, it may also be possiUle to grade the road so that runoff sheet- flows into a heaviiy vegetated area with a well-developed topsoil. Landscaped areas are not adequate. If this area has at least 50 feet of vegetation,then it is generally preferable to use the vegetation to treat runoff,rather than a sediment pond or trap. The 50 feet shall not include wetlands. If ilznoff is allowed to sheetflow through adjacent vegetated areas, it is vital to design the roadways and parlcing areas so that no concentrated tunoff is created. Storin drain inlets shall be protected to prevent sediment-laden water entering the storm dcain system (see BMP C220). 11�Zaintenance Standards Inspect stabilized areas regularly,especially after large storm events. Crusl�ed rocic, gravel base,hog fuel, etc. shall be added as required to maintain a stable driving , surface and to stabilize any areas that have eroded. September 2090 Snohornish Counfy Drainage fJanua! Volume ll-Consfruction Storm�a�ater Pol/ution Prevention 39 Fol(o��-ing construction, these are.as shall be i•estored to pre-constcuction condition or better to prevent future ei•osion i ,i Sepfember 2o10 Snohomish County Drainage Manua! Volume U-Construcfion Stormwater Po!lution Prevention 32 BMP C233: Silt Fence Purpose Use of a siit fence reduces the transpoit of coarse sediinent fi•om a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. See Figure 4.19 for details on silt fence construction. Conditions of Use Silt fence may be used downslope of all disturbed areas. Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial atnounts of overland flow. Any concentrated flows must be conveyed tluough the drainage system to a sediment pond. The only circumstance in which overland flow can be treated solely by a silt fence, rather than by a sediment pond, is when the area draining to the fence is one acre or less and flow rates are less than 0.� cfs. Silt fences should not be constructed in streams or used in V-shaped ditches. They are not an adequate method of silt control for anything deeper than sheet or overland flow. Design and Installation Speci�cations Drainage area of 1 acre or Iess or in combination with sediment basin in a larger site. Maximum slope steepness (normal (pecpendicular) to fence line) 1:1. Maximum sheet or overland flow path length to the fence of 100 feet. No flows greater than 0.5 cfs. The geotextile used shall meet the standards set forth in 2008 WSDOT Standard Specifications, Section 9-33.1 Geosynthetic Matet•ial Requirements, Table 6. Standard strength fabrics shall be suppoi�ted with wll•e mesh, chicken wire, 2-inch x 2-inch wire, safety fence, or jute mesh to increase the strength of t1�e fabric. Silt fence materials are available that have synthetic m.esh backing attached. Filter fabric material shall contain ultcaviolet ray inhibitors and stabilizers to provide a minimum of six months of expected usable construction life at a temperature range of 0°F. to 120°F. 100 percent biodegradable silt fence is available that is str•ong, long lasting, and can be left in place after the project is completed. Standard Notes for construction plans and specifications follow. Refer to Figure 4.19 for standard silt fence details. The contractor shall install and maintain temporaiy silt fences at the locations shown in the Plans. The silt fences shall be constructed in the areas of clearing, grading, or drainage prior to starting those activities. A silt fence shall not Ue considered temporary if the silt fence must function beyond the life of the contract. The silt fence shall prevent soil carried by runoff water from going beneath,through, or over the top of the silt fence, but shall allow the water to pass tht•ough the fence. September 2010 Snohomish County Drainage Manual Volume Il-C�nstruction Stormwater Poilution Prevention 107 ��... .,,<<< i�,��< <�.:l�i:�� ,. 1��'� �1 _��L ��,�.. .��_i � � _ ..��i <<<��, _i« �i��:�i�i.�iiL ii � _ii��i � � _. feet above the original ground surface. The geotextile shall be sewn together at the point of manufacture, or at an approved location as determined by the Engineer,to form geotextile lengths as required. All sewn seams shall be located at a support post. Alternatively,two sections of silt fence can be overlapped,provided the overlap is long enough and that the adjacent fence sections are close enough together to prevent silt laden water from escaping through the fence at the overlap. The geotextile shall be attached on the up-slope side of the posts and support system with staples,wire, or in accordance with the manufacturer's recominendations. 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 geotextile in the forin of a wire or plastic mesh is dependent on the propei-ties of the geotextile selected for use. If wire or plastic bacic-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 back-up support. The 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 shall be bacl�lled and the soil tamped in place over the buried poi�tion of the geotextile, such that no flo�v can pass beneath the fence and scouring cannot occur. When wire or polymeric bacic-up support mesh is used,the wire or polymeric mesh shall extend into the trench a minimum of 3 inches. The fence posts shall be placed or driven a minimum of 18 inches. A minimum depth of 12 inches is allowed if topsoil or other soft subgrade soil is not present and a minimum depth of 18 inches cannot be reached. Fence post depths shall be increased by 6 inches if the fence is located on slopes of 3:1 or steeper and the slope is peipendicular to the fence. If required post depths cannot be obtained, the posts shall be adequately secured by bracing or guying to prevent overtuining of the fence due to sediment loading. Silt fences shall be located on contour as much as possible, except at the ends of the fence,where the fence shall be turned uphill such that the silt fence captures the runoff water and prevents water fi•oin flowing around the end of the fence. If the fence must cross contours,with the exception of the ends of the fence, gravel checic dams ' placed peipendicular to the back of the fence shall be used to minimize concentrated flow and erosion along the back of the fence. The gi•avel checic dams shall be approximately 1-foot deep ' at the bacic 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 siuface behind the fence. The gravel checic dams shall consist of crushed surfacing base course, gravel backfill for walls, or shoulder ballast. The gravel checic dams shall be located every 10 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 3:1. 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 fi•ee of defects such as knots, splits, or gouges. Steel posts shall consist of either size No. b rebar or larger,ASTM A 120 steel pipe with a minimuin diameter of 1-inch,U, T,L; ot� C shape steel posts with a minimum weiglit of 1.35 lbs./ft. or other steel posts having equivalent strength and bending resistance to the post sizes listed. The spacing of the suppoit posts sl�all be a maximum of 6 feet. September 2010 Snohonush County Drainage fJlanual Volume ll-Consfruciion Storrmvater Pollut�on Prevention 908 Fence back-up support, if used, shall consist of steel wire with a maximum mesh spacing of 2 inches, or a prefabricated polymeric mesh. The stcength of the wire or polymeric mesh shall be equivalent to or greater than 180 lbs. grab tensile st�•ength. The polymeric mesh must be as resistant to ultraviolet radiation as the geotextile it supports. Silt fence installation using the slicing method specification details follow. Refer to Figure 4.20 � for slicing method details. "I'he 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 checics 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 suppoi�t the fabric from upstream water pressure. Install posts with the nipples facing away from the silt fence fabric. Attach the fabric to each post with three ties, all spaced within the top 8 inches of the fabric. Attach each tie di:gonally 45 degrees through the fabric,with each puncture at least 1 inch vet-tically apart. In addition, each tie should be positioned to hang on a post nipple when tightening to prevent sagging. 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 allowed above ground level. The rope lock system must be used in all ditch check applications. The installation should be checiced and coi�ected for any deviation before compaction. Use a flat-bladed shovel to tuck fabric deeper into the ground if necessary. Compaction is vitally iinportant for effective results. Compact the soil immediately next to the silt fence fabric with the fi•ont wheel of the tcactor, slcid 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 folu� trips. Mainte�iance Standards If concentrated flows are evident uphill of the fence,they must be intercepted and conveyed to a I sediment pond. It is important to checic the uphill side of the fence for signs of the fence clogging and acting as a ban•ier 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 height of the silt fence, or a second silt fence shall be installed. If the filter fabric(geotextile)has deteriorated due to ultraviolet brealcdown, it shall be replaced. September 201 D Snohomish County Orainage Manual Volume!!-Consfruction Sformwater Po!lution Preventron 109 - --- ----- — -----,i Joints in filter fabric shall be spliced at posts.Use staples,wire rings or 2^Xp°by 14 Ga.wire or , equivalent to attach fabric to posts equivalent if standard strength fabric used � �� Fiiter fabric— II I = I I I �E II I � I I � � - 7�-6'max�� Minimum 4"x4'trench '�J -�� E J �' , " Backfill trench wfth native soll � � Post spacing may be increased or 3/4"-1.5"washed gravel to 8'if wire backing is used 2"x2"wood posls,steel fence posts,or equivalent Figure 4.19—Silt Fence ; � , ': l�>� , ( a ' September 2010 Snohomish Counfy Drainage Manual Volume Il- Consfruction Sformv✓afer Pollution Prevention 190 i r..,�A�r.y�. lOiT�rILCiWOa � waye.3a' 7'wu�.�r Kan n+e� -A'1wsa.�M�W�r��■ •••• •• ••�•••»•••:�OffDb11C atlad I�YAc H � . � „►v....N..«.«t�- �e. �� FL6iY-- Mw�uc#Ni��f /Oir OE►THt �rt hn�e=a�u.iu As�wck Ni�w P�u�� ++�e��M r f�YAc iw�R�wni �. o r.,.L«rr.r.• . 1 o4r.s.n�{.etl iOM�e��sY�n �L�� m�tjn�rrrs6ya J/�\f/��l�� !�J/�ff�/�� . �* �� \� � ��~�,�\��~ . ��,``��\\�\1��# ��\\1.�� I� , .` , /�/ � �� /�J`�/�� Jf�`�� AlfAClMiO�lf OtTALLl: � .....-•� . //�� '��\��\� r GNlyr btMc a�wda,t�wd�4.. ��\.�� \��'\��` .uutsoweo un e1 riton e•or rae�lc. /�`/��/ �/ � �/ �� j\��\\ Psr Poet. mp f��/\`, ��\�\1��\�\\� +roa�io.,r■a,W espwy.p�.�..,y na+ravainc�y �`�l\��\�/ � \�//\`/�`l�`�/� ��.a r+�InN+en N►'ap�eL � . ` � �•F4Ay�scA II�a+�P°r�.�d U�r+�wJ'•. Na more ihwi 24'oi a 38'tabric u�.ut�+r�tw��i�sot,r:. is eltowed ebova ground. Rd ot s�R fante �..�. dppatlnn Posl iiad9ed aRe1 cantpaCdOn fakac � . � �°�rt° Iil Fcrwv ��++� �j�` � . � �� i ti� \ �.4-}.,?:- :ti .., '0.-+.pj5�/ ,s �� f ��~�'t�i��i��, '��'� Z��RLRI`J, y JC• �Y�� .�� .�� . � ' � �r;l��vOE,�+��i ��i � � . i i�t,'ir,�,c r��i'/ �if s�;o� ��,��.>: . .�.'��T� c.•.i,�;:y ,., .. . ' Hot�xRd shbW PdM gen�blede [16 mm�.�2►@ (1 g tnm vdei� . Cwnp�eced ku�eladai ViDr�taryr pdow h na acr�ptabie bocauso oi h�Mai cs�mp�c�lon Figure 4.20—Silt Fence Installation by Slicing Method Sepfember 2090 Snohomrsh County Drainage Manual Vo!ume I!- Construction Stormwater Pollution Prevention 99 9 BMP C120: Temporary and Permanent Seeding , NOTE: Small projects permitted in accordance with SCC 30.63A.810 shall only use �'� BMPs in this section that do not require the in��olvement of a licensed engineer. !, Purpose I' Seeding is intended to reduce erosion by stabilizing e�posed soils. A well-established ve�etative � cover is one of the most effective methods of reducin� erosion. ', Conditions of L'se ! Seeding may be used t}1i•oughout thc project on di�t�:rt�cd ��r��l� that h��c rc:�,hed final ��rade c�r i that will remain unwot•lced for mot•e than 30 days. � Channels that will be vegetated should be installed bct'�r� maj�r ca��h�:.��>>�I: a�ld ]l��,lru�;c�lc�i � with a Bonded Fiber Matrix. The vegetation should be well established (i.e., 75 percent cover� before water is allowed to flow in the ditch. With channels that will have high flows, erosion control blankets should be installed over the hydt�oseed. If vegetation cannot be established f��;,i» ! seed before water is allowed in the ditch, sod should be installed in the bottom of the ditch o�e� ' hydromulch and blankets. ' Retention/detention ponds should be seeded as required. � MUIC�IIST'CCjl'i� 1 �r �I� r;.,�� ._.,i �r,�,��-�CT` �� . � . .. � � �__ � � '1�,� ..JI��:�-�i� � . � - due to runoff. I All disturbed ... _:� :.._.. : .,� , � .. � 1��_ , . ,�: __ __ � � _�;�� . � , �_ '�� ,; completed by the end of September. � �: �: � __ _ . � � �..!� , . I provide more than average protectior . At final site stabilization,all disturbc . .� " �� .I . r. , . `�..... . _.. i� i�� , _..�.i and mulched. Final stabilization means the completion of all soil distui•bing activities at the site ! and the establishment of a permanent vegetative cover, or equivalent permanent stabilization measures (such as pavement,riprap, gabions or geotextiles)which wi11 prevent erosion. Design and Installation Specificatious Seeding should be done during those seasons most conducive to growth and will vary with the climate conditions of the region. Local experience should be used to determine the appropriate seeding periods. The optiinum seeding windows for western Washington are April 1 through June 30 and September 1 through October 1. Seeding that occucs between July 1 and August 30 will require urigation until 75 percent grass cover is established. Seeding that occuis between October 1 and March 30 will require a mulch or plastic cover until 75 percent grass cover is established. To prevent seed from being washed away, confirm that all required surface water cont�ol measures have been installed. September 201 D Snohomish County Drainage Manua! Volume I!-Construcfion Sformwater Po!lution Prevention 33 The seedbed should be firm and rough. All soil should be roughened no matter what the slope. If compaction is required for engineering purposes, slopes must be track walked before seeding. Bacicblading or smoothing of slopes greater than 4:1 is not allowed if they are to be seeded. New and more effective restoration-based landscape practices i•ely on deeper incorporation than that provided by a simple single-pass rototilling treatment. Wherever pr�actical the subgrade should be initially ripped to improve long-term permeability, infiltration, and water inflow qualities. At a minimum,permanent areas shall use soil amendments to achieve organic matter and permeability performance defined in engineered soilllandscape systems. For systems that are deeper than 8 inches the rototilling process should be done in multiple lifts, or the prepared soil system shall be prepaf�ed properly and then placed to achieve the specified depth. Organic matter is the most appropriate form of"fertilizei"because it provides nutrients {including nitcogen,phosphorus,and potassium) in the least water-soluble form. A natural system typically releases 2-10 percent of its nutrients annually. Chemical fertilizers have since been formulated to simulate what organic matter does naturally. In general, 10-4-6 N-P-K (nitrogen-phosphorus-potassium) fertilizer can be used at a rate of 90 pounds per acre. Slow-release fertilizers should always be used because they are more efficient and have fewer environmental impacts. It is recommended that areas being seeded for final landscaping conduct soil tests to determine the exact type and quantity of fertilizer needed. This ' will prevent the over-application of fertilizer. Fertilizer should not be added to the hydromulch '� machine and agitated more than 20 minutes before it is to be used. If agitated too much, the slow-release coating is destroyed. There are numerous products available on the market that talce the place of chemical fertilizers. ' These include several with seaweed ext�•acts that are beneficial to soil microbes and organisms. If 100 percent cottonseed meal is used as the mulch in hydroseed, chemical fertilizer may not be ', necessaiy. Cottonseed meal is a good source of long-term, slow-release, available nitrogen. ' Hydroseed applications shall include a minimum of 1,500 pounds per acre of mulch with 3 percent tackifier. Mulch may be made up of 100 percent: cottonseed meal; fibers made of wood, recycled cellulose, hemp, and Icenaf; compost; or blends of these. Tackifier shall be plant- based, such as guar or alpha plantago,or chemical-based such as polyacrylamide or pol�in�r�, i Any inulch or tacicifier product used shall be installed per inanufacturer's instructions. i - Generall}�, mulches c��r�� in s�-�(1 E��und t�e��. Seed and fertilizer �i�c add�d at tiin� ��f application. MUlC�l1S ZIV�,��t\� I'�'�1111f'CU l;��l' .��i! IC!i��l �'..'1 ,'� �iJ`i!�� !1 I��' �il _�'�:� ,�" � , '�illl�[:lf�::C�',1��V� by hydraseeding. �, � On steep slopes, 13��.��i:�1 l�ih�r �i�:u�� i,!;1�`�1) �_,r `�l��ir.u.ic.�il�� 13u;��i�;( I��il�.r �I�,iria ��1L31��1) � products should be used. BFM/MBFM products are applied at a minimum rate of 3,000 poun ' � per acre of mulch with approximately 10 percent tacicifier. Application is made so that a � ininimum of 95 percent soil coverage is achieved. Products shail be installed per mantif�crn,�� _ instructions. Areas to be permanently landscaped shall provide healthy topsoil that reduces the neeci fertilizers, impt�oves overall topsoil quality, provides for better vegetal health and vitality, improves hydroIogic characteristics, and reduces the need for irrigation September 2010 Snohomish County Drarnage Manual Volume ll-Constructron Stormwater PoUution Prevention 34 Compost, if used, shall meet specifications for Grade A quality compost in Ecology Publication 94-03 8. Areas that will be seeded only and not landscaped may need compost or meal-based mulch included in the hydroseed in order to establish vegetation. Native topsoil should be re-installed ', on the disturbed soil surface befoce application. Seed that is installed as a temporary measure inay be installed by hand if it will be covered by straw,mulch, or topsoil. Seed that is installed as a permanent measure may be installed by hand on small areas(usuaIly less than 1 acre)that will be covered with mulch,topsoil,or erosion blankets. The seed mixes listed below include recommended mixes for both temporaiy 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 soi) amendments or slow-release fertilizers are used. Locai suppliers or the local conseivation district should be consulted for their recommendations because the appropriate mix depends on a variety of factors, including location, exposure, soil type, slope, and expected foot traffic. Alternative seed mixes approved by Snohomish County may be used. Table 4.1 represents the standard mix for those areas where just a temporary vegetative cover is required. Table 4.1 ' Temporaiy Erosion Control Seed Miat %Weight % %Gcrmination Puri Chewings or annual blue grass 40 98 90 restucn rubra var. commtrtata or Poa arrna Pere�mial rye- 50 98 90 Lolium erenne Redtop or colonial bentgrass 5 92 85 A r•ostis alba or A �ostis tenuis White dutch clover 5 98 90 Ti�ifo7itrn�repetas Table 42 pro��ides just one recommended possibility foi•landscaping seed. Table 4.2 Landscaping Seed Mix % %�Vei I�t Purity %Gcrmination Perennial rye blend 70 98 90 Lolitnn erenne Chewings and red fescue blend 30 98 90 Festuca rubra var. commutata or Festuca rz�bra September 2010 Snohomish County Drainage Manual Volume Il-Construcfion StormwaterPollufion Prevenfion 35 The turf seed�nix in Table 4.3 is for dry situations�vhere little�vater is requit�ed. This inix requires very little maintenance. Table 4.3 Low-Gro�ving Turf Seed Mix % \Veigl�t % %Germination Puri � Dwarf tall fescue(several varieties) 45 98 90 Festtrca nrtrndinacea var. Dwarf perennial rye(Barclay) 30 98 90 Loliurn erenne var. bar�cl Red fescue 20 98 90 Festuca r�ubr•a Colonial bentgrass 5 98 90 Agrostis tenuis Table 4.4 presents a mix recommended for bioswales and other intermittently��et areas. Table 4.4 Bioswale Seed Mix %1Veight % "/o Germination Puri � Tall or meadow fescue 75-80 98 90 Fesh�ca ar-trndinacea or Festuca elatior Seaside/Creeping bentgrass 10-15 92 85 i A rostis altrstris Redtop bentgrass 5-10 90 80 i l�rr;�i;s nlh_,or,.l��r�cr;,e.gi,';r�tti��z I In__ , � September 2010 Snoh�mish Counfy Drainage Manua! Volume!I-Construcfion Sformwater Pollution Prevention 36 The seed inix shown in Table 4.5 is a recommended low-growing, relatively non-invasive seed mix appropriate for very wet areas that are not regulated wetlands. Apply this m�ture at a rate of 60 pounds per acre. Table 4.5 Wet Area Seed Mix* %�'Veight % %Germination Pw•i � Tall or meadow fescue 60-70 98 90 Festt�ca a�nrnditaacea or Fest2rca elatior Seaside/Creeping bentgrass 10-IS 98 85 A rostis pahrstris Meadow foxtail 10-15 90 80 Ale oczrrirs ratensis Alsike clover 1-6 98 90 I Tri olitrm hybridum Redtop bentgrass 1-6 92 85 Agrostis alba *Modified Briargreen,Inc. Hydroseeding Guide N�etlands Seed I�lix The meadow seed mix in Table 4.6 is recommended for areas that will be maintained infrequently or not at all and where colonization by native plants is desirable. Lilcely applications include rural road and utility right-of-way. Seeding should take place in September or veiy 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 be a fairly invasive species. If the soil is amended,the addition of clover may not be necessary. Table 4.6 Meado�v Seed Mix %Wcight % %Germination Pw�ity Redtop or Oregon bentgrass 20 92 85 A r•ostis aTba or A �•ostis ore onensis Red fescue 70 98 90 Festa�ca rtrbra White dutch clover 14 98 90 Ti�ifolitrm repens 1blaintenance Standards I Any seeded areas that fail to establish at least 80 percent cover (100 percent co�-er for areas that receive sheet or concentrated flows) shall be reseeded. If reseeding is ineffective, an alternate method, such as sodding, mulching, or nets/blankets, shall be used. If winter v��eather prevents , adequate grass grovvth,this time limit may be rel�ed at the discretion of Snohornish Count�� when sensitive areas would otherwise be protected. After adequate cover is achieved, any areas ,, that experience erosion shall be reseeded and protected by mulch. If the erosion problem is �� dcainage related, the problem shal) be fixed and the ee�oded area reseeded and protected by �T�ulch. I ,I _,�,�__.��,�_:w�_.__._��. �______ - --_-. ----�d�.a_.�._ _�__.v_ .�.�,�_w...� _ �� , I Seeded areas sIiall be supplied �vith adequate moisture, but not watered to the extent that it causes runoff. � i BMP C121: Mulching Purpose The purpose of mulching soils is to provide immediate temporary protection from erosion. Mulch also enhances plant establishment by conserving moisture, holding fertilizer, seed, and topsoil in place, and moderating soil temperatures. There is an enormous ��a►-iet}- of inulches tllat can be used. Only the most common types are discussed in this section. Conditions of Use As a temporary cover measure, mulch should be used: • On disturbed areas that require cover measures for less than 30 days. • As a cover for seed during the wet season and during the hot summer montlis. • During the wet season on slopes steeper than 3H:1 V with more than 10 feet of vertical relief. Mulch may be applied at any time of the year and must be refreshed periodically. Design and Installation Specifications For mulch materials, application rates, and specifications, see Table 4.7. Note: Thicknesses may be increased for disturbed areas in or near sensitive areas or other areas highly susceptible to erosion. Mulch used within the ordinary high-��ater mark of surface waters should be selected to minimize potential flotation of organic matter. Composted organic materials have higher specific gravities (densities) than straw, wood, or chipped material. Maintenance Standards The thickness of the cover must be maintained. Any areas that experience erosion shall be remulched and/or protected with a net or blanket. If the erosion problem is drainage related,then the problem shall be fixed and the eroded area remulched. September 2010 Snohomish County Drainage Manua! Volume!1- Construction Stormwater Poflution Prevention 39 Table 4.7 Mulch Standards and Guidelines ATulch Application 1�'Iaterial Qualit Standards Rates Remarks Straw Air-dried;free from 2"-3"thick;5 Cost-effective protection when applied with adequate undesirable seed and bales per 1000 sf thickness. Hand-application generally requires D eater coarse material. or 2-3 tons per tliickness than blown straw.The thickness of straw may be acre reduced by half when used in conjunction with seeding. [n windy areas straw must be held in place by crimping,using a tackifier,or covering with netting. Blown straw always has to be held in place with a tackifier as even light winds�vill blow it away.Straw,ho«�ever,has several deficiencies that should be considered when selecting mulch materials. It often introduces and/or encourages the propagation of weed species and it l�as no significant long-term benefits. Straw should be used only if mulches�vith long-term benefiu are unavailable locally. It should also not be used within the ordinary high-water elevation of surface��•aters(due to flotation). Hydromulch No grotinh Approx.25-30 Shall be applied with hydromulcher. Shall not be used inhibiting factors. Ibs per 1000 sf without seed and tackifier unless the application rate is at or 1500 -2000 least doubled. Fibers longer than about'/.-1 inch clog Ibs per acre hydromulch equipment. Fibers should be kept to less than'/< inch. Composted No visible water or 2"thick min.; More effective control can be obtained by increasing 1�4ulch and dust during approx. 100 tons thicl:ness to 3". Excellent mulch for protecting final grades Compost handling. Must be per acre(approx. until landscaping because it can be directly seeded or tilled purchased from 800 lbs per yard) into soil as an amendment. Composted mulch has a coarser supplier with Solid size gradation than compost.It is more stable and practical �Vaste Handling to use in wet areas and during rainy weather conditions. Permit(unless exempt). Chipped Site Average size shall 2"minimum This is a cost-effective way to dispose of debris from Vegetation be several inches. thickness clearing and grubbing,and it eliminates the problems Gradations from associated with burning. Generally,it should not be used on fines to 6 inclies in slopes above approx. 10°/a because of its tendency to be length for texture, transported by runoff. It is not recommended within 200 variation,and feet of surface waters. If seeding is expected shortly after interlocking mulch,the decomposition of the chipped vegetation may tie properties. up nutrients important to grass establishment. V4'ood-based No visible water or 2"thick;approx. This material is often called"hoD or hogged fuel." It is Mulch dust during 100 tons per acre usable as a material for Stabilized Construction Entrances handling. Must be (approx.8001bs. (BMP C 105)and as a mulch. The use of mulch ultimately purchased from a per cubic yard) improves the organic matter in the soiL Special caution is supplier with a Solid advised re�arding the source and composition of wood- Waste Handling based mulches. Its preparation typically does not provide Permit or one any weed seed control,so evidence of residual vegetation in exempt from solid its composition or known inclusion of"�eed plants or seeds waste re�ulations. should be monitored and prevented(or minimized). September 2010 Snohomish County Drainage Manual Volume!/-Construction Stormwater Pollution Prevention 40 BMP C140: Dust Control I Purpose '� Dust control prevents w�ind transport of dust from disturbed soil surfaces onto roadv�rays, � drainage ��ays, and surface waters. Conditions of Use In areas (including roadways) subject to surface and air movement of dust where on-site and oft= site impacts to roadw�ays, drainage�vays, or surface waters are likely. Design and Installation Specifications , Vegetate or mulch areas that will not receive vehicle traffic. In areas where planting, mulching, or paving is impractical, apply gravel or landscaping rock. Limit dust generation by clearing only those areas where immediate activity will take place, leaving the remaining area(s) in the original condition, if stable. Maintain the original ground cover as long as practical. Construct natural or artificial windbreaks or windscreens. These may be designed as enclosures far small dust sources. Sprinkle the site with water until surface is wet. Repeat as needed. To prevent carryout of mud , onto street, refer to Stabilized Construction Entrance (BMP C105). Irrigation water can be used for dust control. Irrigation systems should be installed as a first step on sites where dust control is a concern. Spray exposed soil areas with a dust palliative, following the manufacturer's instructions and cautions regarding handling and application. Used oil is prohibited from use as a dust suppressant. PAM (BMP C126) added to water at a rate of 0.� lbs. per 1,000 gallons of water per acre and applied from a water truck is more effective than water alone. This is due to the increased infiltration of w�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 water needed for dust control, especially in eastern V��ashington. 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: • Lower speed limits. High vehicle speed increases the amount of dust stirred up from uripaved roads and lots. • Upgrade the road surface strength by improving particle size, shape, and mineral types tliat make up the surface and base materials. • Add surface gravel to reduce the source of dust emission. Limit the amount of fine particles (those smaller than .075 mm) to 10 to 20 percent. September 2010 Snohomish County Drainage Manual Volume ll- Construction Stormwater Pollution Prevention 60 • Use geotextile fabrics to increase the strength of neiv roads or roads undergoing reconstruction. • Encourage the use of alternate,paved routes, if available. • Restrict use bti tracked vehicles and hea�y trucks to pre��ent damage to road surface and base. • Appl�' C11CI]11Cc11 C�L1St SU]J�JI'2SS3ritS 11Slll�,T T�le 3C�I1111 II7Zt�lOC1. hlellClll]a t�le pl'OC�UCt\L'lt�l Ifle top fe�v inches of surface material. Suppressailts may also be applied as surface treatments. • Pave unpa��ed pei7nanent roads and other trafficked areas. • Use vacuum street sweepers. • Remove mud and other dirt promptly so it does not dry and tl�en turn into dust. • Limit dust-causinQ «�ork on ��-indv davs. Maintenance Standards Respray area as necessar}� to keep dust to a minimum. September 2010 Snohomish County Drainage Manual Volume !1- Construction Stormwafer Polfufion Prevention 61 BMP C220: Storm Drain Inlet Protection Purpose To prevent 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 dow-nslope and within 500 feet of a disturbed or construction area, unless the runoff that enters the catch basin ��ill be conveyed to a sediment pond or trap. Inlet protection may be used anyw�here to protect the drainage system. It is likely that the drainage system will still require cleaning. Table 4.91ists several options for inlet protection. All 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 overflows may be required where stormwater ponding��ould cause a hazard. If an emergency overflow is provided, additional end-of-pipe treatment may be required. Table 4.9 Storm Drain Inlet Protection Applicable for Emergency Paved/Earthen T e of Inlet Protection Overflow Surfaces Conditions of Use Dro Inlet Protection Excavated drop inlet Yes,temporary Earthen Applicable for heavy flows. Easy to protection flooding will maintain. Large area Requirement: 30' occur X 30'/acre Block and gravel drop inlet Yes Paved or Earthen Applicable for heavy concentrated protection flows. Will not pond. Gravel and wire drop inlet No Applicable for heavy concentrated protection flows. Will pond.Can withstand traffic. Catch basin filters Yes Paved or Earthen Fre uent maintenance re uired. Curb Inlet Protection Curb inlet protection with a Small capacity Paved Used for sturdy,more compact wooden weir overflow installation. Block and gravel curb inlet Yes Paved Sturdy,but limited filtration. protection Culvert Inlet Protection Cuh�ert inlet sediment trap 18 month ex ected life. September 2010 Snohomrsh County Drainage Manual Volume !!-Construction Stormwater Pollution Prevenfion 93 _ , i Design and Installation Specifications Excavated Drop Inlet Protection ��i Excavated drop inlet protection is an excavated impoundment around the storm drain. Sediment � settles out of the stormwater prior to entering the storm drain. Depth 1-2 ft as measured from the crest of the inlet structure. Side Slopes of excavation no steeper than 2:1. Minimum volume of excavation 35 cubic yards. Shape basin to fit site��ith longest dimension oriented toward the longest inflo��area. , Install provisions for draining to prevent standing water problems. I', Clear the area of all debris. Grade the approach to the inlet uniformly. �'� Drill weep holes into the side of the inlet. Protect weep holes with screen wire and washed aggregate. Seal weep holes v�Then removing structure and stabilizing area. � It may be necessary to build a temporary dike to the down slope side of the structure to prevent bypass flow. Block and Gravel Filter- Block and gravel filter is a barrier formed around the storm drain inlet with 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. Support subsequent courses by placing a 2x4 through the block opening. Do not use mortar. Lay some blocks in the bottom row on their side for dewatering the pool. Place hardware cloth or comparable wire mesh with '/�-inch openings over all block openings. Place gravel just below the top of blocks on slopes of 2:1 or flatter. An alternative design is a gravel donut. Inlet slope of 3:1. Outlet slope of 2:1. 1-foot wide level stone area between the structure and the inlet. Inlet slope stones 3 inches in diameter or larger. Outlet slope use gravel '/�- to 3/-inch at a minimum tliickness of 1-foot. September 2090 Snohomrsh County Drarnage Manuaf Volume 1!-Construction Stormwater Pollution Prevention 94 Block and Gravel Filter Gravel and �nrire mesh filter is a gravel barrier placed over the top of the inlet. This structui•e does not provide an overflow. Hardware cloth or comparable wire mesh with '/2-inch openings. Coarse aggregate. Height 1-foot or more; 18 inches ��ider than inlet on all sides. Place wire mesh over the drop inlet so that the wire extends a 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 aravel should be at least 12 inches over the entire inlet opening and extend at least 18 inches on all sides. Catchbasin filte��, Catchbasin filters should be designed by the manufacturer for use at construction sites. The limited sediment storage capacity increases the amount of inspection and maintenance required. which may be daily for heavy sediment loads. The maintenance requirements can be reduced b�� combining a catchbasin filter with another type of inlet protection. This type of inlet protection provides flow bypass without overflo��7 and therefore may be a better method for inlets located along active rights-of-wa}�. S cubic feet of stora�e. Dewatering provisions. High-flow bypass that��-i11 not clog under normal use at a construction site. The catchbasin filter is inser-ted in the catchbasin just belo��the gratin�. Curb Inlet Protection ��ith Wooden Weir Curb inlet protection with wooden�veir is a barrier formed around a curb inlet��-ith a ��ooden frame and gravel Wire mesh with '/2-inch openings. Extra strenb h filter cloth. Construct a frame Attach the wire and filter fabric to the frame. Pile coarse washed aggregate against�vire/fabric. Place weight on fraine anchors. September 2010 Snohomish County Drainage Manua! Volume!!-Construction Sformwater Po!lution Prevenfion 95 Block and Gravel Curb Inlet Protection Block and gravel curb inlet protection is a barrier formed around an inlet with concrete blocks and gravel. See Figure 4.15. Wire mesh with '/z-inch openings. Place two concrete blocks on their sides abutting the curb at either side of the inlet opening. These are spacer blocks. Place a 2x4 stud through the outer holes of each spacer block to align the front blocks. Place blocks on their sides across the front of the inlet and abutting the spacer blocks. Place vvire mesh over the outside vertical face. Pile coarse aggregate against the ��ire to the top of the barrier Curb and �utter sediment bairier Curb and gutter sediment banier is a sandbag or rock berm (riprap and aggregate) 3 feet high and 3 feet wide in a horseshoe shape. See Figure 4.16. Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 feet high and 3 feet wide, at least 2 feet from the inlet Construct a horseshoe shaped sedimentation trap on the outside of the berm sized to sediment trap standards for protecting a culvert inlet. September 2010 Snohomish Counfy Drainage Manual Volume ll- Consfruction Stom�water Po!lution Prevention 96 , i ' Pl�n V�ew A �—� �-I�.�,.{`�Q��=, o�,(�� .i �.�e�,��g�]�p 3'J��'3'G'�'S� y:�-=��"Up "3'�,�. ;��:.��b��:�',:i��'�;�'�':��''-��r ��;\��,�°�;'!�: ��-�''��'--��,��.� � G oa c t n�C o t , '�"^r :�< '-'g-��r�� ',j-•y C��'�� i011C:[Bld �.:, ,�Sl � � :'o.•4'u �p C�,7c�7�� t �°��•�� B�OClS :.��_��o ��[1��DQ .�� `��`�`�`}� ��Q�� "�p� .��,�� ,c-�, ��;:� �ci�,�`a�:�. c�arle! �,�; s .r r�, �ti,.��.., � ��,;�+�^�� -�a+. 1�_c� � �'_i� :�ff��'' ,�rfc=zc_�,. ��!'�' 1"� ��t: / ��r• ��t�[�_�^+�,�. � +�i•;�?i�C.��V'.{��Y4 �"��a�•"`-,}=L'��`,r3�i!"t� �i-�"31f,:}''-��'�' J�t � -��rg��''Sr:��Jc�'d'�14J � �'� ��l�,�� '�r�.1�-�Y4 }�'oVh�L��a (� '�Sr �'/'� .^� QJ ��G6C}\+� .�1v .�7`. -:.u�J� �Pl ��' A f � �'��:��?t1 � - A co�crec�Bb�c- �� Ciravel 8addlll �,p„erflnw � yy� �Ponding Height �j�Z,� t� ��,.,� �. wa�� i � '`.�-.��'�� / K.�.e�., T / �%*� s!� �} �� : .�9 ��f!J.� ��/� � ` ♦/ � f �.�. \! �% ! fti. x�' �i��\i L`1\ ��'.\,�� _ � \�l•�� - -i�*'\�'� ��. f�!/f��`��i '��f��. �;f�f\.��;;��/��1' i.��.\' �'� l i��`\.�' �� \i\�% �.'� �, �� fi i?��'�� I .. //�/��j��!� '��;��/i'.�ii �!�;,/�� Notes: 1.Drop inlet sediment barriers are to be used for smail,nearly level drainage areas.(less than 5%a) � 2. Excavate a basin of sufficient size adjacent to the drop inlet. i 3.The top of the structure(ponding height)must be�+�ell below the ground elevation downslope to prevent ' runoff from bypassing the inlet. A temporary dike may be necessary on the downslope side of the structure. Figure 4.14-Block and Gra��el Filter �', Septeri�ber 2010 Sr�c�hornish County Drarna:�e Manu�31 VoJ�une 1l- Constructron Storrz��^,�aterPollufion Prevenfion 97 Plan View Back of Sidewalk A Catch Basin I � �. ri ��,, il '�i �' II i� �i �� l 2x4 Wood Stud ,� � Back of Curb Concrete Block Curb Inlet �a��.`�°°�°� . `��'• � +�oo•o�y-�o• ay �o•o��. ��cQO SX� O. J�O�Q� �,�'�� O O •�ro•o•.�c �v o� �� o• o• ��ac�s� �/�:p • � x F^: .;��/�� . � I lOa° ��v �¢�°o-�•o�c„�°o'�,°o' � I ' � aA.Q°''�,'�Q��'�°-��' o'�i�!' od�:Ga."�� I �' : .o�.�rp�eo' �C\��. �� . � �_� �� `p-'r��.��.Jo• �j`"=-o��'L8�°o�;C.p o Qoo o ,a c,o� 'o �(' ' "a40_�,p`,�& Vb, e�V,� •��•cO,�e• e�.3"�,�o•e` a��'�•o�p�'• •..�'0--o.�bo�.o• c4.;�'0•0• o•p•p'• �,00•p• p�8{��4 C?�'.�'G7'l c• �-\�4. Gc LG O o. '�S^�' o.�t�'O°. 'Q�d'O�P C;So.bG= 2r;��3,�'� �r�zo� 04� ��.� ;�.`�.�c i4��o.bJo. r�.�{J,c �^ �o o• o^ � /� o �a a' oo r�� ao 4�� /p��R: ��pC,l�4-�! `RcR�p•�. �C O�q�S R=:Vp•�S OO� co�°°'�o�°° �o e`o ��c�°� a°o a:� �'°�c• ' � �'o�•o• p��o•�•�;. '�^'� p��'�o.,,obJ"R" „ s c.� �C n or-p a�Jo c -;,��^...ca��' ;�°�'' ' �o�o�� ' ;�;o�� -:o<ao��'��o,�. Wire Screen r � Filter Fabric Concrete Block Section A - A 3��Drain Gravel (20mm) '/4'Drain Gravel (20mm) Ponding Height Concrete Block Overflo r— ;:'o�$'i � i � , 'g •• °,oa;'� � i�� / / - �, � \/��/ � ' '•' �� Curb Inlet ��//\ VA�,��j�j ' • .. A/ �er Fabnc �r /\//\/\�%/��%i�\ � �%/�� Catch Basin \\� 4 Wood Stud / (100x50 Timber Stud) �j�. �� NOTES: 1. Use block and gravel type sediment barrier when curb inlet is located in gentiy sloping street segment, where water can pond and allow sediment to separate from runoff. 2. Barrier shali allow for overflow from 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 4.1�—Block and Gravel Curb Inlet Protection September 2010 Snohomish County Drainage Manual Volume ll-Construction Stormwater Po!lution Prevention 98 Plan View Back of Sidewalk I'� Burlap Sacks to Catch Basin Overlap onto Curb , �\ Curb Inlet �� Back of Curb �'� i ,, i� ' I 1 I 1 � RUNOFF � � �� I RUNOFF SPILLWAY �r/ , �! i / �`, Gravel Filled Sandbags ';',\ Stacked Tightly � NOTES: 1.Place curb type sediment barriers on gently sloping street segments,where water can pond and allow sediment to separate from runoff. 2.Sandbags of either burlap or woven'geotexrile'fabric,are filled with gravel,layered and packed tightly. 3.Leave a one sandbag gap in the top row to provide a spillway for overflow. 4.Inspect barriers and remove sediment after each storm event.Sediment and gravel must be removed from the traveled way immediately. Figure 4.16—Curb and Gutter Barrier September 2010 Snohomish County Drainage Manua/ Volume ll- Construction Stormwater Pollution Prevention 99 ��laintenance Standards Catch basin filters should be inspected tiequently, especially after stonn events. If the insert becomes clogged, it should be cleaned or replaced. For systems using stone filters: If the stone filter becomes clogged with 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 would be to use the clogged stone as fill and put fresh stone around the inlet. Do not wash sediment into storm drains v��lule cleaning. Spread all excavated material evenly over the surrounding land area or stockpile and stabilize as appropriate. I � BMP C209: Outlet Protection Purpose Outlet protection prevents scour at conveyance outlets and minimizes the potential for i downstream erosion by reducing the velocity of concentrated stormwater flows. Conditions of Use � � Outlet protection is required at the outlets of all ponds, pipes, ditches, or other conveyances, and where runoff is conveyed to a natural or manmade drainage feature such as a stream, «�etland, lake, or ditch. I Design and Installation Specifications I� The receiving channel at the outlet of a culvert shall be protected from erosion by rock lining a minimum of 6 feet downstream and extending up the channel sides a minimum of 1—foot above the maximum tailwater elevation or 1-foot abo��e the crown, whichever is higher. For large pipes (more than 18 inches in diameter), the outlet protection lining of the channel is lengthened to four times the diameter of the culvert. Standard wingwalls, and tapered outlets and paved channels should also be considered when appropriate for permanent culvert outlet protection. Organic or synthetic erosion blankets, with or without vegetation, are usually more effective than rock, cheaper, and easier to install. Materials can be chosen using manufacturer product ; specifications. ASTM test results are available for most products and the designer can choose the correct material for the expected flow. With low flows, vegetation(including sod) can be effective. I', The following guidelines shall be used for riprap outlet protection: � • If the discharge velocity at the outlet is less than 5 fps (pipe slope less than 1 percent), use 2-inch to 8-inch riprap. Minimum thickness is 1-foot. ', • For 5 to 10 fps discharge velocity at the outlet(pipe slope less than 3 percent), use 24- � inch to 4-foot riprap. Minimum thickness is 2 feet. • For outlets at the base of pipes sloping 10 percent or greater with a 10-foot vertical elevation drop, an energy dissipater shall be designed and constructed in accordance with EDDS Chapter 5-OSL, Pipe Ends and Outfall Systems. Filter fabric or erosion control blankets should always be used under riprap to prevent scour and , channel erosion. New pipe outfalls can provide an opportunity for low-cost fish habitat improvements. For example, an alcove of lo��-velocity water can be created by constructing the pipe outfall and associated energy dissipater back from the stream edge and digging a channel, over-widened to the upstream side, from the outfall. Overwintering juvenile and migrating adult salmonids may use the alcove as shelter during high flows. Bank stabilization, bioengineering, and habitat September 2010 Snohomish County Drainage Manua! Volume!!- Construction Stormwater Po!lution Prevention 91 features may be required for disturbed areas. See Volume V for more information on outfall system design. Maintenance Standards Inspect and repair as needed. Add rock as needed to maintain the intended function. Clean energy dissipater if sediment builds up. il , Septem6er 2010 Snohomish County Drainage Manua! Volume I!- Construction Stormwater Pollution Prevention 92 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 specific element is not functioning as designed and an alternative BMP needs to be implemented. Stake and Wire Fence (BMP C104) Sediment Trap (BMP C240) � Temporary Sediment Pond (BMP C241) Straw Bale Barrier (BMP C230) Brush Barrier (BMP C231) Gravel Filter Berm (BMP C232) Vegetated Strip (BMP C234) Straw Wattles (BMP C235) Nets and Blankets (BMP C122) Plastic Covering (BMP C123) Interceptor Dike and Swale (BMP C200) Grass-Lined Channels (BMP C201) Check Dams (BMP C207) Concrete Handling (BMP C151) Sawcutting and Surface Pollution Prevention (BMP C152) �2013 D. R. STRONG Consulting Engineers Inc. Page 23 of 39 Stormwater Pollution Prevention Plan Piper"s Bluff January 31,2012 ! 1 . BMP C104: Stake and Wire Fence Purpose Fencing is intended to: (1)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, (4)protect any areas �vhere marking with survey tape may not provide adequate protection. Conditions of Use To establish clearing limits, stake or wire fence may be used: I • At the boundary of sensitive areas, their buffers, and other areas required to be left uncleared. • As necessary, to control vehicle access to and on the site. Design and Installation Specifications I See Figure 4.1 for details. . More substantial fencing shall be used if the fence does not prevent encroachment into those areas that are not to be disturbed. , Maintenance Standards If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. _. Survey Flagging Baling Wire Do Not Nail or Staple Wire to Trees 3' AIIN. 10'-20' Metal Fence Post —I I I I I I—I I I—I I I—I I I—I I I 1 I—I I I—I I I-11 I— I I—I I ,; 12 MIN. � Figure 4.1 —Stake and VVire Fence September 2010 Snohomish County Drainage Manua! Volume ll-Construction Stormwater Po!lution Prevention 26 ,I BMP C240: Sediment Trap Purpose A sediment trap is a small temporaiy ponding area with a gravel outlet used to collect and store sediment fi�om sites cleared and/or graded during construction. Sediment traps,along with other perimeter controls, shall be installed before any land disturbance talces place in the drainage area. Conditions of Use Prior to leaving a construction site, stormwater runoff must pass throttgh a sediment pond or trap or other appropriate sediment removal best management practice. Non-engineered sediment traps may be used on-site prior to an engineered sediment tcap or sediment pond to provide additional sediment removal capacity. It is intended for use on sites where the tributary drainage area is less than 3 acres, with no unusual drainage features, and a projected build-out time of 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 vegetation and/or sri•uctures. Sediment traps and ponds are only effective in removing sediment down to about the medium silt size fraction. Runoff with sediment of finer grades(fine silt and clay) will pass through unheated, emphasizing the need to cont��ol erosion to the maximum extent first. Whenever possible, sediment-laden water shall be discharged into onsite,relatively level, vegetated areas (see BMP C234—Vegetated Strip). This is the only way to effectively remove fine particles from runoff unless chemical treatment or filtration is used. This can be particularly useful after initial treatment in a sediment trap or pond. The areas of release must be evaluated on a site-by-site basis in order to determine appropriate locations for and methods of releasing runof£ Vegetated wetlands shall not be used for this purpose. Frequently, it may be possible to pump water from the collection point at the downhill end of the site to an upslope vegetated area. Pumping shall only augment the treatment system, not replace it, because of the possibility of �ump failure or runoff volume in excess of pump capacity. All projects that are constructing permanent facilities for runoff quantity control should use the rough-graded or final-graded permanent facilities for traps and ponds. This includes combined facilities and infilt�ation 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 are 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. Either a permanent contt•ol structure or the temporary control stivcture (described in BMP C241, Temporary Sediment Pond) can be used. If a permanent control structure is used, it may be advisable to partially restcict the lower orifice with gravel to increase residence time while still allowing dewatering of the pond. A shut-off valve may be added to the control structure to allo�v complete retention of stormwater in emergency situations. In this case, an emetgency o��erflo�v «�eir must be added. September 2010 Snohomrsh County Drainage M,anual Volume 11-Construction Stormwater Po!lufion Prevention 196 A slcimmer may be used for the sediment trap outlet if approved by Snohomish County. Design and Installation Specif'ications See Figures 4.22 and 4.23 for details. If permanent runoff control facilities are part of the project,they should be used for sediment retention. To determine the sediment trap geometcy, first calculate the design surface area(SA) of the trap, measured at the invet-t of the weir. Use the following equation: II — SA — FS(QzIVS) where Q2 = Design inflow based on the peak discharge from the developed 2-year runoff event fi•om the contributing drainage area as computed in the hydrologic analysis. The 10-year peak flow shall be used if the project size, expected timing and duration of construction, or downstream conditions wai7ant a higher level of protection. If no hydrologic ' , analysis is required,the Rational Method may be used. VS = The settling velocity of the soil particle of interest. The 0.02 mm (inedium silt)particle with an assumed density of 2.65 g/cm3 has been selected as the particle of interest and has a settling velocity{VS) of 0.00096 ft/sec. FS = A safety factor of 2 to account for non-idea( settling. Therefore, the equation for computing surface area becomes: SA = 2 x QZ/0.00096 or 2080 square feet per cfs c�f itlflo�� Even if permanent facilities are used,they must still have a surface area fhat is at least as lar�e as that derived fi•om the above formula. If they do not, the pond must be enlarged. To aid in deterinining sediment deptli, all sediment traps shall have a staff gauge ��it11 a prominent marlc 1-foot above the bottom of the trap. Sediment traps may not be feasible on utility projects due to the Iimited work space or th� sl��,rt- term nature of the t��orlc. Portabie.tanks may be used in place of sediment traps for uti I lYlaiutenance Standay�ds I' Sediment shall be removed fi•om the trap when it reaches 1-foot in ' �' September 2010 Snohomish County Drainage Manual Volume!1-Construction Stormwater Po!lufion Prevention 117 i 5urface area detemtinet� 4�� M�n�� at top ofw�ir \ � � � �`- �, 7�Mln,Dv��l�,w �„ � _, _ ,._.. � �.. � � ..r. _.:. �, ._. - � �' � '1``in. . ��.�'_ Gryy J , : i"��` _1'Min. � J.d�-�� ! .4 � �1.�'Min. �' � �`�, �'�f-' � Flet�ottom � � � � � '�"-1 a*" � 2'-4"Ro�k RlpRap�� ihfeaha d gravrl Note; Trap rns�be fiormed by berm or kay GeoE�tlle ,f f p��tial or campl�k��xcavaklori � ' Dischar�e to statail�zed c�nv�yanc�, t�utl�t,or levf�l spreader Figure 4.22 Cross Section of Sediment Trap 6' Min. 1'Min. depth overFlow spillwa –��—��—��—��—��—�� y —��—��—��—��—��—� ii-i i i_i i i-iTi-i i i-I I I I I I I- ` , - , r� I I I�;i i i-iTi-Ti-iTi-i i i_ Native soil or ��_�� - ' ' �� in. 1'depth compacted backfill ��_� ' ` �`� —��{- 2"-4'° rock Geotextile -��—��—��—��—��=��_��=)��—��' Min. 1'depth 314"-1.5" _��-��,-�� -�� -��-��,-� washed gravel Fi6i�r•e 4.23 �ecliment Tran nutic�� September 2010 Snohomish County Drainage Manual VoJume!!-Construction Stormwafer Po!lufion Prevention 918 i BMP C241: Teinporaiy Sediment Pond NOTE: structures having a maximum storage capacity at the top of the dam of 10 acre-ft(435,600 ft3) or more are subject to the Washington Dam Safety Regulations (Chapter 173-175 WAC). Pu►•pose Sediment ponds remove sediment fi•om runoff originating from disturbed areas of the site. Sediment ponds are typically designed to remove sediment no smaller than medium silt(0.02 min). Consequently;the}� usl�ally reduce turbidity only slightly. Conditions of Use Prior to leaving a consn•uction site, stormwater runoff must pass through a sediment pond or other appropriate sediment removal best management practice. A sediment pond shall be used where the contributuig drainage area is 3 acres or more. Ponds must be used in conjunction with erosion cont�ol practices to reduce the amount of sediment flo��ing into the basin. Design and Installation Specificatio�is Sediment basins must be installed only on sites where failure of the structure would not cesult in l loss of life, damage to homes or buildings, or inteiTuption of use or setvice of public roads or utilities. If fencing of the pond is required, the type of fence and its location shall be shown on the ESC plan. See Figure 4.24, Figure 4.25, and Figuce 4.26 for details. If permanent iunoff control facilities are part of the project,they should be used for sediment retention. The surface area requirements of the sediment basin must be inet. This may require enlarging the permanent basin to comply with the surface area requirements. If a permanent contcol snucture is used, it inay be advisable to partially restrict the lovver orifice with gravel to increase residence time while still allowing dewatering of the basin. Use of infiltration facilities for sediinentation basins during construction tends to clog the soils and reduce their capacity to infiltrate. If infiltration facilities are to be used, the sides and bottom of the facility must only be rough excavated to a minimum of 2 feet above final grade. Final grading of the infiltration facility shall occur only when all contributing drainage areas are fitlly stabilized. The infiltcation pretreatment facility should be fully constructed and used with the sedimentation basin to help prevent clogging. Deteirnining Pond Geometry Obtain the discharge from the hydrologic calculations of the pealc flow for the 2-year runoff event(Q2). The 10-year pealc flow shall be used if the project size, expected timing and duration of construction, or do��vnstceam conditions warrant a higher level of protection. If no hydrologic analysis is required,the Rational Method may be used. September 2010 Snohomish County Drainage Manual Volume Il- Construcfion Stormv✓afer Pollution Prevention 919 Determine the required surface area at the top of the riser pipe with the eyuation: SA = 2 x QZ/0.00096 or 2080 square feet per cfs of inflow See BiviP C240 for more information on the derivation of the surface area calculation. The basic geometry of the pond can now be deterinined using the following design criteria: Required surface area SA (fi�om Step 2 above) at top of riser. Minimum 3.5-foot depth from top of riser to bottom of pond. Maximuin 3:1 interior side slopes and maximum 2:1 exterior slopes. The interior slopes can be increased to a maximum of 2:1 if fencing is provided at or above the inaximum water surface. One foot of fi•eeboard between the top of the riser and the crest of the emergency spillway. Flat bottom. Minimum 1-foot deep spillway. Length-to-width ratio between 3:1 and 6:1. Sizing of Discharge Mechanisms. The outlet for the basin consists of a combination of principal and emergency spillways. These outlets must pass the pealc runoff expected fi�om the contributing drainage area for a 100-year storm. If, due to site conditions and basin geometry, a separate emergency spill-way is not feasible, the principal spillway must pass the entire peak runoff expected fro�n the 100-year storm. However, an attempt to provide a separate emergency spillway should always be made. The runoff calculations should be based on the site conditions during construction. The flow through the dewatering orifice cannot be utilized when calculating the 100-year storm elevation because of its potential to become clogged; therefore, available spillway storage must begin at the principal spillway riser crest. The principal spillway designed by the procedures contained in this standard will result in some reduction in the pealc rate of runoff. However,the riser outlet design will not adequately control the basin discharge to the predevelopment discharge limitations as stated in SCC 30.63A.550. Howe��er, if the basin for a permanent stormwater detention pond is used for a temporary sedimentation basin,the control stcucture for the permanent pond can be used to maintain predevelopment discharge limitations. The size of the basin,the expected life of the construction project, the anticipated downstream effects and the anticipated weather conditions during construction, should be considered to determine the need of additional discharge control. See Figure 4.27 for riser inflo�i-curves. September 2010 Snohomish County Drainage Manual Volume li-Cons!rucfion Sformwater Po!lufion Prevention 920 BMP C230: Straw Bale Barrier Purpose To decrease the velocity of sheet flows and intercept and detain small amounts of sediment from distui•bed areas of limited extent,preventing sediment from leaving the site. See Figure 4.17 for details on straw bale barriers. Conditions of Use Below disturbed areas subject to sheet and rill erosion. Where the size of the drainage area is no greater than 1/4 acre per 100 feet of barrier length; the maximum slope length behind the barrier is 100 feet; and the inaximum slope gradient behind the barrier is 2:1. Where effectiveness is required for less than three months. Straw bale bacriers shall not be constructed in streams, channels, or ditches. Straw bale barrieis shall not be used where rocic or hard surfaces prevent the fulI and uniform anchoring of the barrier. Design and Installation Speci�cations Bales shall be placed in a single row, ]engthwise on the contour,with ends of adjacent bales tightly abutting one another. , All bales shall be either wire-bound or sh•ing-tied. Straw bales shall be installed so that bindings I are oriented around the sides rather than along the tops and bottoms of the bales in order to prevent deterioration of the bindings. The barrier shall be entrenched and bacl�lled. A trencl� shall be excavated the width of a bale and the length of the proposed barrier to a minimum depth of 4 inches. The trench must be deep enough to remove all grass and other material that might allow underflow. After the bales are staked and chinlced (filled by wedging),the excavated soil shall be backfilled against the barrier. Bacicfill soil shall conform to the ground level on the downhill side and shall be built up to 4 inches against the uphill side of the barriet•. Each bale shall be securely anchored by at least two stakes or re-bais driven through the bale. The first stake in each bale shall be driven toward the previously Iaid bale to force the bales together. Stakes or re-bars shall be driven deep enough into the ground to securely anchor the bales. Stakes should not extend above the bales but instead should be driven in flush �vith the top of the bale for safety reasons. The gaps between the bales shall be chinl<ed (filled by��edging)with straw to prevent water fi•om escaping between the bales. Loose straw scattered ovec the area immediately uphill fi�oni a straw bale barrier tends to inerease barrier efficiency. Wedging must be done careful(y in order not to separate the bales. September 2010 Snohomish County Drainage Manua! Volume!1-Construcfion Stormwater Pollution Prevention 1 Q 9 Maintenance Standards Straw bale barriers shall be inspected iminediately after each runoff-producing rainfall and at least daily during prolonged rainfall Repair damaged bales and erosion around or under bales. Sediment deposits should be removed after each runoff-producing rainfall. They must be removed when the level of deposition reaches approxiinately one-half the height of the barrier. Any sediment deposits remaining in place after the straw bale barrier is no longet•required shall be dressed to conform to the existing grade,prepared and seeded. Straw bales used as a temporary straw bale barrier shall be removed after project completion and stabilization to prevent sprouting of unwanted vegetation. , �_ . September 2010 Snohomish Counfy Drainage Manual Volume 1!-Construction Stormwater Pollution Prevention 902 I SC'��rt i�_� ��.g. (1.5-1,SmJ r� � i Ponding Height �A p �1 �,� � Emlr�d Stratv Bal� �,� \ �� .� ,� 4"{160mm}IAiri�m � into Soil . Angle�ke Ta�rard Pr�t�iaus Balato '�BCtIQi't � -� A Pro�Cfa Tigt�Rt � r t q . � . , � A �o�darShke ur Ret�r Urk� Tl�our,�ba l�. ' -- �'N�� .� ,�� B B xar�: � I�I i.The x�ra��beles�hall l�e p�.�d on sl��.x conto�. 2.B al�t�t�o��l��e d"n�r�v K%ith ffee�t��tly abuttin�, 3_Kcy in hnica la pcctenl u�tm nr naw�da ba Ica Figure 4.17 Stra�v Bale Barrier II BMP C231: Brush Barrier Purpose The purpose of biush barriers is to reduce the transport of coarse sediment from a construction site by providing a temporaty physical barrier to sediment and reducing the rvnoff velocities of overland flo�v. �� Conditions of Use Brush barriers may be used do��mslope of all disturbed areas of less than one-quarter acre. Brush barriers are not intended to treat concentrated flows,nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment pond. The only circumstance in which overland flow can be treated solely by a barrier, rather than by a sediment pond, is when the area draining to the barrier is small. Brush bart•iers should only be installed on contours. Design and Installation Specifications Height 2 feet(minimum) to 5 feet(maximum). Width 5 feet at base (minimum)to 15 feet(maximum�. Filter fabric(geotextile) may be anchored over the br�� , the barrier. Ten-ounce burlap is an adequate alternative to tilter fabri� Chipped site vegetatior ' ' ' ' ' , ' ' ' construct brush barriei� A 100 percent biodegr�.. _. . . _ _ . _ by��looden stal.es. Figure �.18 depicts a typical brush barrier. Maintenance Standards There shall be no signs of erosion or concentrated runoff under or around the barrier. If concentrated flows are bypassing the bairier, it must be expanded or augmented by toed-in filter fabric. The dimensions of the barrier must be maintained. September 2010 Snohomish County Drainage Manual Volume ll-Construction Stormv✓ater Po!lution Prevention 104 If required,drape filter fabric over brush and secure in 4'k4" � min.trench with compacted - backfill. �\; � �\\1 � � � C � ,•:-;.. , ' p�� - �� _�1 \ �� " �Anchor downhill edge of �-- filter fabric with stakes, ��'` � �� sandbags,or equivalent. �� i�p,j< � �s i�.��1-. I;F� ��„'^-.�� ,�i�� ' 4�r �"�=11--�`�2'Min.Height Min.5'wide brush barrier with ' max.6"diameter woody debris. Alternatively topsoil strippings may be used to form the barrier. Figure 4.18—Brush Barrier Sepfember 2010 Snohomish County Drainage Manua! Volume Il-Consfruction Stormti^✓ater Pollution Prevenfion 905 BMP C232: Gravet Filter Berm Purpose A gravel filter berm is constcucted on rights-of-way or traffic areas within a construction site to retain sediment by using a filter berin of gravel or crushed roelc. Conditions of Use Where a temporary measure is needed to retain sediment fi�om rights-of-way or in traffic areas on constr�uction sites. Design and Installation Specifications Berm material shall be 3/o to 3 inches in size,washed well-graded gravel or crushed rock with less than 5 percent fines. Spacing of berms: • Every 300 feet on slopes less than 5 percent • Every 200 feet on slopes between 5 percent and 10 percent • Eveiy 100 feet on slopes greater than 10 percent Berm dimensions: • 1 foot high with 3:1 side slopes 0 8 linear feet per 1 cfs runoff based on the 10-year, 24-hour design storm Maintenance Standards Regular inspection is required. Sediment shall be removed and filter material replaced as needed. September 2090 Snohomish County Drainage Manua! Volume Il- Construcfion Stormwater Po!lution Prevention 106 BMP C234: Vegetated Strip Purpose Vegetated strips reduce the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use Vegetated strips may be used downslope of all disturbed areas. Vegetated strips are not intended to treat concentrated flows,nor ai•e they intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment pond unless the criteria in table 4.11 are met. TaUle 411 Vegetated Strips AveraQe Slo e Slo e Percent Flow ath Len h 1.SH:1 V or less 67%or less 100 feet 2H:1 V or less 50%or less 115 feet 4H:1 V or less 25%or less 150 feet 6H:1 V or less 16.7%or less 200 feet l OH:l V or less 10%or less 250 feet llesign and Installation Specifications The vegetated strip shall consist of a minimum of a 25-foot wide continuous strip of dense , vegetation with a permeable topsoil. Grass-covered, landscaped aceas are generally not adequate because the volume of sediment ove�•whelms the grass. Ideally,vegetated strips shall consist of undisturbed native growth with a well-developed soil that allows for infiltration of runoff The slope within the strip shall not exceed 4H:1 V. The uphill boundary of the vegetated strip shall be delineated with clearing limits. Maintenance Standards Any areas damaged by erosion or construction activity shall be seeded immediately and protected by mulch. If more than 5 feet of the ariginal vegetated strip width has had vegetation removed or is being eroded, sod must be installed. If there are indications that concentrated flows are traveling across the buffer, surface u�ater controls must be installed to reduce the flows entering the buffer, or additional perimeter protection must be installed. September 2090 Snohomish County Drainage Manua! Volume I!-Construction Stormwater Polluflon Prevention 112 BMP C235: Straw Wattles Purpose Straw wattles are temporary erosion and sediment control barriers consisting of straw that is wrapped in biodegradable tubular plastic or similar encasing material. They r•educe the velocity and can spread the flow of rill and sheet runoff, and can capture and retain sediment. Straw wattles are typically 8 to 10 inches in diameter and 25 to 30 feet in length. The wattles are placed in shallow trenches and staked along the contour of disturbed or newly consti-ucted slopes. See Figure 4.21 for typical const�-uction details. Conditious of Use Disttu�bed areas that require immediate erosion protection. Exposed soils during tl�e period of short construction delays, or over winter months. On slopes requiring stabilization until permanent vegetation can be established. Straw wattles are effective for one to tv�,�o seasons. If conditions are appropriate,wattles can be staiced to the ground using willow cuttings for added revegetation. Rilling can occur beneath wattles if not properly entcenched and water can pass between wattles if not tightly abutted together. Design and Installation Specifications I It is critical that wattles are installed perpendicular to the flow direction and parallel to the slope contour. !, Narrow trenches should be dug across the slope on contour to a depth of 3 to 5 inches on clay soils and soils with gradual slopes. On loose soils, steep slopes, and areas with high rainfall, the trenches should be dug to a depth of 5 to 7 inches, or 1/2 to 2/3 of the thickness of the wattle. Stai�t building tcenches and installing wattles from the base of the slope and work up. Excavated material should be spread evenly along the uphill slope and compacted using hand tamping or other methods. Construct trenches at contour intervals of 3 to 30 feet apart depending on the steepness of the slope, soil type, and rainfall. The steeper the slope the closer together the trenches. Install the wattles snugly into the trenches and abut tightly end to end. D�not overlap the ends. Install stalces at each end of the wattle,and at 4-foot centers along entire length of wattle. If required, install pilot holes for the stalces using a straight bar to drive holes through the wattle and into the soil. At a minimum, wooden stalces should be approximately 3/4 x 3/4 x 24 inches. Willow cuttings ot�3/8-inch rebar can also be used foc stakes. September 2010 Snohomish County Drainage Manua! Volume I!-Construcfion Stormwater Po!lution Prevention 113 Maintenance Standards Stalces should be driven through the middle of the wattle, leaving 2 to 3 inches of the stalce protruding above the wattle. Wattles may require maintenance to ensure they are in contact with soil and thoroughly entrenched,especially after significant rainfall on steep sandy soils. Inspect the slope after significant storms and repair any areas where wattles are not tightly abutted or water has scoured beneath the wattles. September 2010 Snohomish County Drainage Manua! Volume ll-Construction Stormwater Pollution Prevention 194 3-4' �� l � ` (1.2m) �" �Ny � � � � � � Straw Rolls Must �\�� Be Placed Along �j�\ Slope Conlours j�� pdJacent rolls shall y ` � tighUy abut� / \ � //� �✓� \/\\��`�- �°�Y % ` ' \� � � � ��`\',� 10'-25'(3-8m) r � .�\� \ �y � ��/�� i�,/�� \//\ . �j/ Spacing Depends � on Soll Type and � ,(�� Sedfinent,organlc matter, Slope Steepness % and natNe seeds are �''�� aptured behind the rolis. %\ �� \ /, /��i� 3"-5"(75-125mm) I } %� \ � �/�\�� 8"-10"DIA. %� , � '�//�� (200-250mm) � \i�\ • � \/ . '� Live Stake � � /�� \� I' _�Y �� /. ' �� 1" X 1" Stake � not to scale (25 x 25mm) l 1� A� NOTE: � 1.Straw roll installation requires the placement and secure staking of the roll in a trencb,3"-5"(75-125mm) deep,dug on contour. runoff must not be allowed to ran under or aro�md roll. Figure 4.21 —Straw Wattles September 2010 Snohomish County Drainage Manua! Volume I!-Consfrucfion Sformwafer Pollution Prevention 115 BMP C122: Nets and Blankets Purpose Erosion control nets and blanlcets are intended to prevent erosion and hold seed and mulch in place on steep slopes and in channels so that vegetation can become weli established. In addition, some nets and blanicets can be used to permanently reinforce turf to protect drainage ��ays during high flows. Nets (commonly called matting) are stc•ands of material woven into an open, but high-tensile strength net(for example, coconut fiber matting). Blankets are strands of material that are not tightly woven,but instead form a layer of interlocicing fibers,typically held together by a biodegradable or photodegradable netting (for example, excelsior oi�straw blankets). They generally have lower tensile strength than nets, but cover the ground more completel}�. Coir(coconut fiber)fabric comes as both nets and blankets. Conditions of Use Erosion control nets and blankets should be used: • To aid permanent vegetated stabilization of slopes 2H:1 V or greater and with more than 10 feet of vertical relief. • For drainage ditches and swales (highly recommended). The application of appropriate netting or blanlcet to drainage ditches and swales can protect bare soil fi•om channelized runoff while vegetation is established. Nets and blanlcets also can capture a great deal of sediment due to their open,porous structure. Synthetic nets and blanlcets can be used to permanently stabilize channels and may provide a cost-effective, environmentally preferable alternative to riprap. 100 percent synthetic blanlcets manufactured for use in ditches may be easily reused as temporary ditch liners. Disadvantages of blanlcets include: • Surface preparation required; • On slopes steeper than 2.5:1, bIanket installers may need to be roped and harnessed for safety; • They cost at least$4,000-6,000 per acre installed. Advantages of blankets include: • Installation does not require special equipment or extensive training • Blanlcets can be installed in stages or phases as the project progresses; I • Seed and fertilizer can be hand-placed by the installers as they progress do��n the slope; I � Blankets can be installed in any weathe�: � • There are numerous types ofblankets tl�at can l�c �i��i��ied ��ith ��:u i�,us j�.lramctcr; in mind. Those parametei•s include: fibei• blend, lnesll stre.ngtll, longevity, biode�radabilit��. � cost, and availability. I September 2010 Snohomish County Drainage Manual Volume ll- Construction Storm�a�ater Pollution Prevenfion 41 Design and Installation Specifications See Figure 4.4 and Figure 4.5 for typical orientation and installation of blankets used in channels and as slope protection.Note: these are typical only; all blankets must be installed per manufacturer's installation instructions. Installation is critical to the effectiveness of these products. If good ground contact is not achieved, runoff can concentrate under the product,resulting in significant erosion. Blanlcets on slopes shall be installed according to manufacturer's instructions. Further guidance may be obtained from the 2005 Ecology Stormwater Management Manual for Western Washington. Jute matting must be used in conjunction with mulch (BMP C121). Excelsior,woven straw blankets and coir(coconut fiber)blanlcets may be installed without mulch. In general, most nets (e.g.,jute matting)require mulch in order to prevent erosion because they have a fairly open structure. Blankets typically do not require mulch because they usually provide complete protection of the surface. Extremely steep, unstable,wet, or rocky slopes are often appropriate candidates for use of synthetic blanlcets, as are riverbanlcs,beaches and other Iligh-energy environments. If synthetic blankets are used, the soil should be hydromulched first. Maintenance Standards Good contact with the ground must be maintained, and erosion must not occur beneath the net or blanket. Any areas of the net or blanlcet that are damaged or not in close contact with the ground shall be I repaired and stapled. ; If erosion occurs due to poorly controlled drainage,the problem shall be fixed and the eroded � area protected. � September 2010 Snohomish County Drainage Manual Volume!I-Construction Stormwater Pollution Prevention 42 � � � �G �� '� Cr' � /��/j��/ � � . . .. � ,�t2•, • . �/\��\��// /�/��/\�/ \��\m� � o ��/�//��//�� . �/��/��/�� /�/��/��/ �/��, .�/i�/i�/��, � � {750 m) � � �6'Ii50rtvn) : Longitudinal AnchorTrench Terminal Slope and Channel Anchor Trench � �� I � ,1s � �F iF � �,\i�. � P �.,� � � � � � � � Stake at 3'-5' �� ' � � (1-1.5m)Intervais. � � P , G' P J"�,. �� P G��a�o,� �' I P (� 0� P , P � ��\/��\/�\/� ,. (�' ! �\��\//,; /��/� Chedc slot at 25'(7.6m)fntero_ P ��'� Isometric Vie� � P �/ /�/ ��\\i\�i� P �� P s•(150mm) , • /.i,� \\ \ �. ///\�//\�//\�// a �,� (JOOmmJ . �//\\//\� ' •o� • /\///\�//\� //��\��\��\�\o; �/��' \�\��\ � � �\�j\�j\ �� /��/��/��/ ��\� �\��\ (150mm} /�\��\��\ Initial Channel Anchor Trench Intermittent Check Slot NOTES: 1.Check slots to be constructed per manufacturecs specifications, 2.Staking or stapling layout per manufacturers specifications. Figure 4.4—Channel Installation September 2010 Snohomish County Drainage Manua! Volume 1!-Construction Stormwater Pollution Prevention 43 Slope surface shail be smooth 6efore piacement for proper soii contact. If there is a berm at the Sta lin attem as er .� top of slope,anchor P 9 P P upslope af the berm. manufacturer'srecommendatio�s. �� •'�•'•:�`.'";,,t,i•;,'•',:•;•. � �� Min.2" i i ��': .•:.::�, I I� Overlap � � � � _��i!—�Anchor in 6"x6"min.Trench � i —„—. and staple at 12" intervals. ' �`'�;� � _ li�� Min.6"overfap. ,� � �i `'I'_�. -I I - -- ^�, .�_ � - I� '��=1 I I_�f�_��__-��_� '':�::'.': � Staple overlaps '_i I I—��_��i��i��r�� - max.5"spaang. Bring material down to a level area,tum Do not stretch blankets/mattings tight- the end under 4"and staple at 12"intervals. allow the rolls to mold to any irregularities. For sbpes less than 3H:1 V,rolls Lime,fertilize,and seed before installation. may be placed in horizontal strips. Planting of shrubs,trees,etc.Should occur after installation. � €'i��t�rc -R.�— Sf�z��c tnctallnti��ii � � !� � � ' � 1 Sepfember 2010 Snohomish County Drainage Manua! Volume!1-Consfruction Stormwater Po!lution Prevention 44 BMP C123: Plastic Covering Pur ose P Plastic covering provides immediate, shoi�t-teim erosion protection to slopes and disturbed areas. Conditions of Use Plastic covering may be used on disturbed areas that require cover 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 breakdown of most polyethylene sheeting malces it unsuitable for long-term (greater than six months)applications. • Cleae plastic sheeting can be used over newly-seeded areas to create a greenhouse effect � and encourage grass growth if the hydroseed was installed too late in the season to establish 75 � percent grass cover, or if the wet season stacted earlier than normal. Clear plastic should not be used for this puipose during the summer months because the resulting high temperatures can kill the grass. • Due to rapid iunoff caused by plastic sheeting, this method shall not be used upslope of areas that might be adversely impacted by concentrated runoff. Such areas include steep and/or unstable slopes. • Whenever plastic is used to protect slopes, water collection measures must be installed at the base of the slope. These measures include plastic-covered berms, chatuiels, 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 with dii-ty ivnoff from a project. Plastic covering may also be used foi: • Temporary ditch liner; • Pond liner in temporary sediment pond; e Liner for bermed temporary fuef storage area if plastic is not reactive to the type of fuel I�� being stored; ', • Emergency slope protection during heavy rains; and, ; • Temporary drainpipe ("elephant trunlc"}used to direct«�ater. I � September 2010 Snohomish County Drainage Manua! Vo/ume I!-Construction Stormwater Pollufion Prevention 45 Design and Installation Specifications Plastic sheeting shall have a minimum thickness of 6 mils (0.006 inches, or 0.15 mm). Plastic slope cover must be installed as follows: • Run plastic up and down slope,not across slope; • Plastic may be installed perpendicular to a slope if the slope length is less than 10 feet; . Minimum of 8-inch overlap at seams; • On long or wide stopes, or slopes subject to wind, all seams should be taped; • Place plastic into a small(12-inch wide by b-inch deep) slot t�•ench at the top of the slope and bacl�ll with soil to lceep water fi•om flowing underneath; e Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and pound a wooden stake tht•ough each to hold them in place; . Inspect plastic for rips,tears, and open seams regularly and repair immediately. This prevents high velocity runoff fi•om contacting bare soil which causes extreme erosion; • Sandbags may be lowered into place tied to ropes. However, all sandbags must be stalced in place. • If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable protection shall be installed at the toe of the slope in order to reduce the velocity of i�unoff Maintenance 5tandards • Torn sheets must be replaced and open seams repaired. • If the plastic begins to deteriorate due to ultraviolet radiation, it inust he completely removed and replaced. • When the plastic is no longer needed, it shall be completely removed. Septen�ber 2090 Snohomrsh County Drainage Manual Vo!ume!1-Construction Sform�rvater Pollution Prevenfion 46 4.2 Runoff Conveyance and Treatment BMPs BMP C200: Interceptor Dilce and S��ale Purpose Provide a ridge of compacted soil,or a ridge with an upslope swale, at the top or base of a disturbed slope or along the perimeter of a disturbed construction area to convey stormwater. Use the dilce and/or swale to intercept the runoff from unprotected areas and direct it to areas where erosion can be controlled. This can prevent storm runoff from entering the worlc area or sediment-laden runoff fi•om leaving the construction site. Conditions of Use Where the iunoff fi•om an exposed site or disturbed slope must be conveyed to an erosion control facility which can safely convey the stormwater. Locate upslope of a constcuction site to prevent runoff from entering disiurbed area. � � When placed horizontally act•oss a disturbed slope, it reduces the amount and velocity of runoff flowing down the slope. Locate downslope to collect runoff from a disturbed area and direct it to a sediment basin. Design and Installation Specifications Dilce and/or swale and channel must be stabilized with temporary or permanent vegetation or other , channel protection during construction. . Channel requires a positive grade for drainage; steeper grades require channel protection and check dams. Review construction for areas where overtopping may occur. Can be used at top of new fill before vegetation is established. j May be used as a pei7nanent diversion channel to carry the iunoff. I Sub-basin tributary area should be one acre or less. Design capacity for the pealc flow fi•om a 10-year, 24-hour storm, assuming a Type lA rainfall distribution, for temporary facilities. Alternatively, use 1.6 times the 10-year, 1-hour flow indicated by an approved continuous runoff model. Facilities that will also seive on a permanent basis must be designed and consti�ucted in accordance with Chapters 30.63A and 30.63B SCC, and Snohomish County EDDS. September 201 D Snohomish County Drainage Manua! Volume!!-Construction Stormwater Pollufion Prevention 67 Dike material compacted 90°/a modified proctor CPEP or equivalent pipe .:«Y� : �—�� (� � � ��=��WT Interceptor Dike' �� - �(�I-�_ ��\ �.. 12' AIIN..: � . �-)��- .. � � � ,� � �� — Provide riprap pad � �=-�� or equivalent energy � - dissipafion Discharge to a stabilized Standard flared watercourse,sediment retention end section facility,or stabilized outlet Inlet and all sections must be securely fastened together with gasketed tivatertighifittings Figure 4.10 -Pipe Slope Drain September 2010 Snohomish County Drainage N,anual Volume 11-Construction Stormwater Pollution Prevention 80 ( u I BMP C201: Grass-Lined Channels Purpose To provide a channel with a vegetative lining for conveyance of runoff. See Figure 4.8 for typical grass-lined channels. Conditions of Use This practice applies to construction sites where concentrated runoff needs to be contained to prevent erosion or flooding. When a vegetative lining can provide sufficient stability for the channel cross section and at lower velocities of water(normally dependent on grade). This ineans that the channel slopes are generally less than 5 percent and space is available for a relatively large cross section. Typical uses include roadside ditches,channels at property boundaries,outlets for diversions, and other channels and drainage ditches in low areas. Channels that will be vegetated should be installed before major earthworlc and hydroseeded with a bonded fiber matrix{BFNI}, The vegetation should be well established(i.e., 75 percent cover)before water is allowed to flow in the ditch. With channels that will have high flows, erosion contcol blankets should be installed over the hydt•oseed. If vegetation cannot be established from seed before v�later is allowed in the ditch, sod should be installed in the bottom of the ditch in lieu of hydromulch and blankets. Design and Installation Speci�cations Locate the channel where it can conform to the topography and other features such as roads. Locate them to use natural drainage systems to the greatest extent possible. Avoid sharp changes in alignment or bends and changes in grade. Do not reshape the Iandscape to fit the drainage channel. The maximum design velocity shall be based on soil conditions,type of vegetation, and method of revegetation,but at no times shall velocity exceed 5 feet/second. The channel shall not be ovei�topped by the peak runoff from a 10-year, 24-hour storm, assuming a Type lA rainfall distributian." Alternatively,use 1.6 times the 10-year, 1-hour flow indicated by an approved continuous runoff model to determine a flow rate which the channel must contain. Grass-lined channels that will also function as pet•manent stormwater conveyance facilities must be designed and constructed in accordance with Chapters 30.63A and 30.63B SCC, and Snohomish County EDDS. An established grass or vegetated lining is required before the channel can be used to convey stormwater,unless stabilized with nets or blankets. If design velocity of a channel to be vegetated by seeding exceeds 2 ft/sec, a temporary channel liner is required. Geotextile or special mulch protection such as fiberglass roving or straw and netting provide stability until the vegetation is fully established. See Figure 4.9. September 2090 Snohomish County Drainage Manual Volume Il-Consfruction Stormwater PoNution Prevention 70 Check dams shall be removed when the grass has matured sufficiently to protect the ditch or - swale unless the slope of the swale is greater than 4 percent. The area beneath the check dams shall be seeded and mulched immediately after dam removal. If vegetation is established by sodding,the pennissible velocity for established vegetation may be used and no temporary liner is needed. Do not subject grass-lined channel to sedimentation from disturbed areas. Use sediment- trapping BMPs upstream of the channel. V-shaped grass channels generally apply where tlie quantity of water is small, such as in short reaches along roadsides. The V-shaped cross section is least desirable because it is difficult to � stabilize the bottom where velocities may be high. '� Trapezoidal grass channels are used where runoff volumes are large and slope is low so that velocities are nonerosive to vegetated linings. (Note: it is difficult to construct small parabolic � shaped channels.) Subsurface drainage, or riprap channel bottoms, may be necessary on sites that are subject to prolonged wet conditions due to long duration flows or a high water table. Provide outlet protection at culvert ends and at channel intersections. Grass channels, at a minimum, should cai-�y peak ivnoff for temporary construction drainage facilities fiom the 10-year,24-hour storm without eroding. Where flood hazard exists, increase the capacity according to the potential damage. Grassed channel side slopes aene►•ally are c.onsti•ucted 3:1 oi-flatter to aid in t}le establishnle►lt of vegetation and for maintenancc. COI1StCUCtC�l8C1C101Sa1211T11i11U1I1 Ot��.� tOOI 1;11'�_�'f ;iI'��UIl.! I'1C [�:C�F`�1�:�V� I�=) ;1��'.1� l��l' ��I� ��LI��lll_ C�U''1[lt� >Z�C�f�c'Cj l�t'C��t'3tl(1!1C :l!l�j ��i�� ".I;�i{Li�� Jlaiutcna�icc �taut�tar�l•� During the establishmeut periuc�; cil��i: brass-lined ciiailn�l� ait�r e��ry rainTai� After grass is established,periodically check the channel; checic it after every heavy rain[ event. Immediately malce repairs. It is particularly important to check the channel ovtlet and all road ci�ossings for banlc stab i I i i� and evidence of piping or scouc holes. Remove all significant sediment accumulations to maintain the designed can•ying capacity. Keep the grass in a healthy, vigorous condition at all times, since it is the primary erosion protection for the channel. September 2090 Snohomish County Drainage Manua/ Volume!I-Construction Sformwater Po!lufion Prevention 71 Typical V-Shaped Channel Cross-section �� +i �, �� 1 ��1��, /� �'��/ri \��,1 �i\\\j\��///� 11`�^\\\\ .�\/\�//� t\�\ \\//�/ ,��V i � i��/��l/��.,y ��"��\��'/ / % � M �\j��//� \��, / �� 6 -9 Filter � /\�/ (�50-225mm) Fabric ��i�/�� Key in Fabric Grass-Lined � With Rock Center Typical Parabolic Channel Cross-Section �li li�v, 1�'�i�� til�i,\��li I a\,�1��h�\I..�h�l ,a r�l�f�G;� �, ' h��lG, ��\ ,� ��' �1.� �1��'�� /i��/ ��i�. ��'� �r „�� /�// :�/. „ . � ��'��Iii,�V- � / g^-g�� ,\� �� \� \ \ •�\, ' (150-225mm) \ \ \, /��Filter �i��/��i�� Key In Fabric ��// //,/ Fabric With Channel Liner With Rock Center f�r Base Flow Typical Trapezoidal Channel Cross-Section I.��ii�v, I� �ti��v1Vl� f � �, ` v,� Design Depth �ia�� //�//� ��,��f ��' // �/��//\. �\�/\ /,�� , ' / / \�� //�, �, . ��\.•I�G '��IVIi1„7 U�r�,�tilvJ,v�l� �J Idl��1��5b�i��V��^ �/��\/ vercut channel 2^(6omm� / / / / / / / to allow bulking during .��,��,.��j��j ��,�\��\�� seedbed preparation ,�/�� and growth of vegetation. Filter� With Rock Center For Base Flow Fabric Figure 4.8—Typical Grass-Lined Channels Sepfember 2010 Snohomish County Drainage Manual Volume!!-Consfrucfron Stormwater Pollution Prevention 72 I' �'�iG,; Overlap 6"(150mm) minimum i�� '�7 y�� \ \� '�� ,� Excavate Channel to Design ��,�� / / �,\ \�///, \� �� i Grade and Cross Section \�� /\�/// ' ��//� ,./��i ,� �T��, �,�. � �� i,� Design Depth � �� OVERCUTCHANNEL �=G�, ' Longitudinal 2'(50mm)TOALLOW ''-� �V� anchor trench BULK/NGDUA/NGSEEDBED �/ ��'�� i41r/, .l�l .V� �d� PHEPAHAT/ON � �//�/�.//��///�/i �' � P e•(tsomm) TYPICAL/NSTALLAT/ON W/THEROS/ONCONTROL �/��/ /��/�� '� � �/� /� /� BLANKETS OR TURF �� j�� /\�/\�':° � �\\/\\ HE/NfORCEMENT MATS ��/\/\�/ /\�/\�/\� �/��//�� s• ,� � /��/��/ ��\\��\\�� \\��\\�� \ �\ (150mm) /�� j� /��/��/\n5oinm) \�\�� Intermittent Check Slot Longitudinal Anchor Trench Shingle-lap spliced ends or begin new roll in an intermittent check slot � -�� w�- Prepare soi!and apply seed before � O � , installing blankets,mats or other � LL �� temporary channel liner system (7 � W V '� �� U �� . � v� � . . � � �v�� ,� v� ��-- ; �'`�'� � � ��, ��. X� . . ,�i '��r�!� � � ',�\��;�j\\//,i,,�j� NOTES: �� 1.Design velocities exceeding 2 ft/sec(O.Sm/sec)require temporary blankets,mats or similar liners to protect seed and soil until vegetation becomes established. 2.Grass-lined channels with design velocities exceeding 6 ft/sec(2m/sec)should include turf reinforcement mats, Figure 4.9—Temporary Channel Liners Sepfember 201 D Snohomisl�County Drainage Manual Volume 11- Consfruction Stormwafer Po!lution Prevenfion 73 BMP C207: Check Dams Purpose Construction of small dams across a swale or ditch reduces the velocity of concentrated flow and dissipates energy at the checic dam. Conditions of Use Where temporary channels or permanent channels are not yet vegetated, channel lining is infeasible, and velocity checks are required. NOTE: use of check dams in receiving waters may require approval from Washington State Department of Fish and Wildlife or other state or federal regulatory agencies. Design and Installation Speci�cations Whatever material is used,the dam should form a triangle when viewed fi•om the side. This prevents undercutting as water flows over the face of the dam rather than falling directly onto the ditch bottom. Check dams in association with sumps work more effectively at slowing flow and retaining sediment than just a checic dam alone. A deep sump should be provided immediately upstream of the checic dam In some cases, if carefully located and designed, check dams can remain as permanent installations with very minor regrading. They may be left as either spillways, in which case accumulated sediment would 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 filled bags. Numerous new products ' are also available for this purpose. They tend to be re-usable, quick and easy to install, effective, � and cost efficient. ' Check dams should be placed perpendicular to the flow of water. I The maximum spacing between the dams shall be such that the toe of the upstream dam is at the same elevation as the top of the downstream dam. ; Keep the maximum height at 2 feet at the center of the dam. I Keep the center of the checic dam at least 12 inches lower than the outer edges at natural ground elevation. ICeep the side slopes of the checic dam at 2:1 or flatter. Key the stone into the ditch banks and extend it beyond the abutments a minimum of 18 inches to avoid washouts from overflow around the dam. Use filter fabric foundation under a rock or sand bag check dam. If a blanlcet ditch liner is used, this is not necessary. A piece of organic ar synthetic blanket cut to fit will also work for this purpose. September 2090 Snohomish County Drainage Manual Volume!!-Construction Stormwater Pollution Prevention 86 Rocic checic dams shall be constructed of appropriately sized rock. The rocic must be placed by hand or by mechanical ineans (no dumping of rocic to form 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 rocic used must be large enough to stay in place given the expected design flow through the channel. In the case of grass-lined ditches and swales, all check dams and accumulated sediment shall be removed when the grass has matured sufficiently to protect the ditch or swale -unless the slope of the swale is greater than 4 percent. The area beneath the checic dams shall be seeded and mulched immediately after dam removal. Ensure that channel appurtenances, such as culvert entrances below check dams, are not subject to damage or blockage from displaced stones. Figure 4.13 depicts a rypical rock check dam. Maintenance Standards Check dams shall be monitored for performance and sediment accumulation during and after each runoff producing rainfall. Sediment shall be removed when it reaches one half the sump depth. Anticipate submergence and deposition above the checic dam and erosion fi•om high flows around the edges of the dam. If significant erosion occurs behueen dams, install a protective riprap liner in that portion of the channel. i � September 2010 Snohomish County Drainage Nanua! Volume I!-Construction Sformwater Pollufion Prevention 87 View Looking Up�tream 1s��a.5m) A 12"{15amm) � �\\�\\�� \ ��o: �o��"c� • o (� �� /\ /.' %.//,.///. �/.�/�� ' e��aQa��`-'o� ��"o�� °�� 24"{Q.�fTI} NOTE: \ �� e-�',�o�"��O°p ��g00;� ° �i, �j\ j e 2:b4Y�'�'��o° r extend It beyond the abuiments� �\� ��i\��// minim�un of 18"(O.�m}io prevent A flow around dam. Section A - A �zow � ~`-� 24"(0.6m) d I ooe �o � �e o � ','\//\\\//\\\// / g �\ oe �Q�oo e,00�a .//,,/i• '� i��/ \ ��\��\f�\�\�\' \i � ,�\��\��\/��/ti�l��i��j/�\�/ /�\�/� �/\\.,/ �� 8'{2.4m} � Spacing Between Check Dams ;, 'L'=1he distanoe such ihat paints'A'and 'B'are of equal elevation. 'L' a 0 g , a °�.��.�°�4 �� PoiNr�A, Poinrr�e� ��\/j�\/��\j�\/�\/�\/�j�j ��, . . r,��i.�/i./�. /..//�\��\��\��\�\�\ \ �. a ��jo,..o \\/�\�/��\��\\/��\\��\�%\�/\��%��'��/ �/ / / �.�\,��j��\��\�� /�,./i, NOT 70 SCALE Figure 4.13—Check Dams � i �� September 2010 Snohomish Counfy Drainage Manual Volume ll-Constructron Stormwater Pollution Prevention 88 BMP C151: Concrete Handling Purpose Concrete work can generate process water and slurry that contain fine particles and high pH, both of which can violate water quality standards in the receiving water. This BMP is intended to minimize and eliminate concrete process water and slurry from entering waters of the state. Conditions of Use Any time concrete is used,these management practices shall be utilized. Concrete construction projects include, but a��e not limited to,the following: • Curbs • Sidewalks • Roads • Bridges • Foundations • Floors . Runways Design and Installation Speci�ications Concrete truck chutes,pumps, and internals shall be washed out only into formed areas awaiting installation of concrete or asphalt. Unused concrete remaining in the truck and pump shall be returned to the originating batch plant for recycling. Hand tools including,but not limited to, screeds, shovels, rakes, floats, and trowels shall be washed off only into formed areas awaiting installation of concrete or asphalt. Equipment that cannot be easily moved, such as concrete pavers, shall only be washed in areas that do not directly drain to natural or constructed stormwater conveyances. Washdown from areas such as concrete aggregate driveways shall not drain directly to natural or , constructed stormwater conveyances. �' When no formed areas are available,washwater and leftover product shall be contained in a lined ! container. Contained concrete shall be disposed of in a manner that does not violate groundwater ' or surface water quality standards. �I Maintenance Standards Containeis shall be checked for holes in the liner daily during concrete pours and repaired the , same day. �� I September 2090 Snohomish Counry Drainage Manua! Volume I!-Construction Stormwater Pollution Prevention 63 �I BMP C152: Sawcutting and Surfacing Pollution Prevention Purpose Sawcutting and surfacing operations generate slurry and process water that conta.ins fine particles and high pH (concrete cutting),both of which can violate the water yuality standards in the receiving water. This BMP is intended to minimize and eliminate process water and sluriy from entering waters of the State. Conditions of Use Anytime sawcutting or surfacing operations talce place,these management practices shall be utilized. Sawcutting and sut�facing operations include, but are not limited to, the following: • Sawing . Coring • Grinding . Roughening • Hydro-demolition . Bridge and road surfacing Design and Installation Specifications Slurry and cuttings shall be vacuumed during cutting and surfacing operations. Slurry and cuttings shall not remain on permanent concrete or asphalt pavement overnight. Slurry and cuttings shall not drain to any natural or constructed drainage conveyance. Collected slurry and cuttings shall be disposed of in a inanner that does not violate groundwater or surface water quality standards. I Process water that is generated during hydro-demolition, surface roughening or similar o erations shall not drain to an natural or constructed draina e conve ance and shall be I P Y g Y disposed of in a manner that does not violate groundwater or surface water quality standards. I Cleaning waste material and demolition debris shall be handled and disposed of in a manner that does not cause contamination of water. If the area is sv��ept with a pick-up sweeper,the material � must be hauled out of the area to an appropriate disposal site. � Maintenance Standards ; Continually monitor operations to determine whether slurry, cuttings, or process water could enter waters of the state. If inspections show that a violation of water quality standards could occur, stop operations and irrunediately implement preventive measures such as berms, barriers, secondary containment, and vacuum trucks. September 2010 Snohomish County Drainage Manua! Volume!I-Consfruction Stormwater Pollufion Prevention 64 • Use geotextile fabrics to increase the strength of new roads or roads undergoing reconstruction. • Encourage the use of alternate,paved routes, if available. • Restrict use by tracked vehicles and heavy trucics to prevent damage to road surface and base. . Apply chemical dust suppressants using the admix method, blending the product with the top few inches of surface material. Suppressants may also be appIied as surface t►•eatments. • Pave unpaved permanent roads and other trafficked areas. • Use vacuum sh•eet sweepers. . • Remove mud and other dirt promptly so it does not diy and then turn into dust. • Limit dust-causing«�orlc on windy days. Maintenance Standards Respray at•ea as necessary to keep dust to a miniinum. Sepfember 2090 Snohomish County Drainage f✓lanua! Volume !1- Constrcrction Stormwater Pol(ution Prevenfion 61 APPENDIX D - GENERAL PERMIT �s�2013 D. R. STRONG Consulting Engineers Inc. Page 24 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2013 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 onsite at all times during construction, and that inspections be performed and documented as outlined below. At a minimum, each inspection report or checklist shall include: a. Inspection date/times b. Weather information: general conditions during inspection, approximate amount of precipitation since the last inspection, 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) why e. A description of stormwater discharged from the site. The presence of suspended sediment, tu�bid 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. I g. General comments and notes, including a brief description of any BMP I 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 I 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". ��2013 D. R.STRONG Consulting Engineers Inc. Page 25 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31, 2013 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 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 heafth or the environment, the Permittee shall comply with the Noncompliance Notification requirements in Special Condition S5.F of the permit. �;2013 D. R. STRONG Consulting Engineers Inc. Page 26 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2013 SITE INSPECTION FORM General Information Project Name: Inspector Name: Title: CESCL# : Date: Time: Inspection Type: ❑ After a rain event ❑ Weekly ❑ Turbidity/transparency benchmark exceedance ❑ Other Weather Precipitation Since last inspection In last 24 hours Description of General Site Conditions: Inspection of BMPs Element 1: Mark Clearing Limits BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Ac`.ion BMP: Inspected Functioning Location Y N Y N NIP Problem/Co�rective Action �I I Element 2: Establish Construction Access BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 3: Contro!Flow Rates � BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action �_ � _ .� F; ST��":G C ��_„�. F �r � �,_ P 3 " :f�� S'��rr;�a`:r Pol�.f�� Prcven:n�� Pla�� P��par s E�.f' Ja�oary �1 2��13 � _ _ . BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 4: InstaU Sediment Controls BMP: ` Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Location Inspected Functioning Problem/Corrective Action Y N Y � N NIP BMP: __ Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 5: Sfabilize Soils BMP: _ Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP :�2013 D. R. STRONG Consulting Engineers Inc. Page 28 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31, 2013 , � BMP: Inspected Functioning , Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 6: Protect Slopes BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action E/ement 7: Protect Drain Inlets BM P: . Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: I Inspected Functioning Location Y N Y N NIP Problem/Corrective Action O 2013 D. R. STRONG Consulting Engineers Inc. Page 29 of 39 I Stormwater Pollution Prevention Plan Piper's Bluff January 31, 2013 � Element 8: Stabilize Channels and Outlets BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 9: Control Po!lutants BMP: Inspected Functioning Location Y N Y ! N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 10: Control Dewatering _ . BMP: - inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action O 2013 D.R.STRONG Consulting Engineers Inc. Page 30 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2013 � BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Stormwater Discharges From the Site Observed? Problem/Corrective Action Y �N Location Turbidity Discoloration Sheen Location Turbidity Discoloration Sheen Water Quality Monitoring Was any water quality monitoring conducted? ❑ Yes ❑ No If water quality monitoring was conducted, record results here: . anspare, _ or le: was Ecology notified by phone within 24 hrs? � Yes ❑ No If Ecology was notified, indicate the date, time, contact name and phone number below: Date: Time: Contact Name: Phone#: General Comments and Notes Include BMP repairs, maintenance, or installations made as a result of the inspection. Were Photos Taken? ❑ Yes o No If photos taken, describe photos below: O 2013 D.R.STRONG Consulting Engineers Inc. Page 31 of 39 Stormwater Pollution Prevention Plan PipePs Bluff January 31,2013 APPENDIX F - ENGINEERING CALCULATIONS PRE-DEVELOPED HOURLY TIME STEP MODELING INPUT: .� . w�t.x - .. � Land llse Summary , F �`�-�` , ��`'�'' � �r ,`� �+ �.� Y �.� �Area 7 Till Forest 4•98 acres Till Pasture U.00 acres Till Grass U.00 acres Outwash Forest U.00 acres Outwash Pasture 0.00 acres Ouiwash Grass 0.00 acres Wetland O.OU acres Impervious 0.00 acres Total � 4.98 acres Scale Factor : 1.U0 Hourly Reduced Time Series: predev >? Compute Time Series I Modify User Input � File for computed Time Series [.TSFJ ` ` ;� . PRE-DEVELOPED HOURLY TIMF STFp M�nFi �ti�� ^� !Tp! �T Flow Frequency Analysis Time Series File:predev.ts Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Pro'. (CFS) (CFS) Period 0.314 2 2/09/Ol 18:00 0.402 1 100.00 O. G 0.085 7 1/06/02 3: 00 0.314 2 25.00 0. 9 0.233 4 2/28/03 3: 00 0.241 3 10.00 0. 9� 0.008 8 3/24/04 20:00 0.233 4 5.00 0.8 0.139 6 1/05/05 8:00 0.204 5 3.00 0. 6� 0.241 3 1/18/06 21:00 0. 139 6 2.00 0.5. 0.204 5 11/24/06 4:00 0. 085 7 1.30 0.2 0.402 1 1/09/08 9:00 0.008 8 1. 10 0. 0' (` -,m•-•.-� `� �,�=1.� . �^'" �!l ^(` !� _ __ __ _ __ il DEVELOPED HOURLY TIME STEP MODELING INPUT: ' r� -�- ,, �� ,� - � ��,= .. � Land Use Summary - ��,� .� - � �: _. � Area � � - Till Forest 0.00 acres Till Pasture 0.00 acres Till Grass 7•87 acres Ouiwash Forest 0.00 acres I Outwash Pasture 0.00 acres Ouiwash Grass 0.00 acres �i Wetland 0.00 acres ' Impervious 3.17 acres i Total 4.98 acres Scale Factor : 1.00 Hourly Reduced Time Series: DEV » Compute Time Series I Modi User In ut �Y P File for computed Time Series [.TSFJ _ � DEVELOPED HOURLY TIME STEP MODELING OUTPUT: Flow Frequency Analysis Time Series File:dev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.928 6 2/09/O1 2:00 1.88 1 100.00 0. 990 0.757 8 1/05/02 16:00 1. 19 2 25.00 0. 960 1. 12 3 2/27/03 7:00 1. 12 3 10. 00 0.900 0.820 7 8/26/04 2:00 0. 987 4 5. 00 0.800 0. 987 4 10/28/04 16:00 0. 985 5 3.00 0. 667 0. 985 5 1/18/06 16:00 0. 928 6 2.00 0.500 1. 19 2 10/26/06 0:00 0.820 7 1.30 0.231 1.88 1 1/09/08 6:00 0.757 8 1. 10 0.091 Computed Peaks 1.65 50.00 0. 980 G 2013 D.R.STRONG Consuking Engineers Inc. Page 33 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2013 � FLOW CONTROL FACILITY DESIGN OUTPUT Retention/Detention =ac�-lity Type of Facility: Detention Pond Side Slope: 3.00 H: 1�T Pond Bottom Length: 33.00 ft Pond Bottom Width: 16.00 =t Pond Bottom Area: 528. sq. ft Top Area at 1 ft. FB: 13038. sq. ft 0.299 acres Effective Storage Depth: 14.00 ft Stage 0 Elevation: 410.00 ft Storage Volume: 69132. cu. ft 1.587 ac-ft Riser Head: 14 .00 ft Riser Diameter: 18.00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 0.88 0.079 2 10.00 1.50 0.122 4.0 3 10.70 1.40 0.097 4.0 Top Notch Weir: None Outflow Rating Curve: None �tage Elevation Storage Discharge Percolation-- Surf Area ;-t) (ft) (cu. ft) (ac-ft) (cfs) (cfs) (sq. ft) ' �. GO 410.00 0. 0.000 0.000 0. 00 528. �. Ol 410.01 5. 0.000 0.002 0. 00 531. 0. 02 410.02 11. 0.000 0.003 0.00 534 . 0.03 410.03 16. 0.000 0.003 0.00 537. 0.04 410.04 21. 0.000 0.004 0.00 540. 0.05 410.05 27 . 0.001 0.005 0.00 543. 0.06 410.06 32. 0.001 0.005 0.00 546. 0.07 410.07 38. 0.001 0.006 0.00 549. 0.35 410.35 203. 0.005 0.012 0.00 635. 0. 62 410.62 387. 0.009 0.017 0.00 724. 0.90 410.90 603. 0.014 0.020 0.00 822. 1.17 411.17 838. 0.019 0.023 0.00 921. 1.45 411.45 1111. 0.026 0.025 0.00 1030. 1.72 411.72 1404. 0.032 0.028 0.00 1140. 1. 99 411.99 1727. 0.040 0.030 0.00 1256. 2.27 412.27 2096. 0.048 0.032 0.00 1381. 2.54 412.54 2486. 0.057 0.033 0.00 1507 . 2.82 412.82 2927 . 0.067 0.035 0.00 1643. 3.09 413.09 3389. 0.078 0. 037 0.00 1780. 3.37 413.37 3908. 0.090 0. 039 0.00 1928 . 3. 64 413.69 4448. 0.102 0.040 0.00 2075. 3. 92 413.92 5052. 0.116 0.042 0.00 2234 . 4. 19 414.19 5676. 0.130 0.043 0.00 2392. 4.47 414 .47 6369. 0.146 0.044 0.00 2561. 4.74 414 .74 7083. 0.163 0.046 0.00 2730. 5.01 415.01 7844. 0.180 0.047 0.00 2905. O 2013 D.R. STRONG Consufting Engineers Inc. Page 34 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2013 5.29 415.29 �683. 0. 199 0.048 O. 00 3091. 5.56 415.56 9543. 0.219 0.050 0.00 3276. 5.84 415.84 10487 . 0.241 0.051 0.00 3473. 6.11 416.11 11451. 0.263 0.052 0.00 3668. 6.39 416.39 12507. 0.287 0.053 0.00 3877 . 6.66 416.66 13582. 0.312 0.054 0.00 4083. 6. 94 416.94 14755. 0.339 0. 055 0.00 4302. 7.21 417.21 15946. 0.366 0.056 0.00 4519. 7.49 417.49 17249. 0.396 0.057 0.00 4750. 7.76 417.76 18557. 0.426 0.058 0.00 4977. 8.03 418.03 19932. 0.458 0.060 0. 00 5210. 8.31 418.31 21425. 0.492 0.061 0. 00 5457 . 8.58 418.58 22931. 0.526 0.062 0.00 570-. 8.86 418.86 24564 . 0.564 0.063 0.00 5959. 9.13 419.13 26207. 0. 602 0.063 0.00 6213. 9.41 419.41 27984. 0. 642 0.064 0.00 6482 . 9.68 419. 68 29770. 0.683 0.065 0.00 6747 . 9. 96 419. 96 31698. 0.728 0.066 0.00 7027. 10.00 420.00 31980. 0.734 0.066 0.00 7068. 10.02 420.02 32122. 0.737 0.067 0.00 7088. 10.03 420.03 32192. 0.739 0.068 0.00 7098. 10.05 420.05 32335. 0.742 0.071 0.00 7119. 10.06 420.06 32406. 0.744 0.074 0.00 7129. 10.08 420.08 32549. 0.747 0.078 0.00 7149. 10.09 420.09 32620. 0.749 0.083 0.00 7160 . 10. 11 420.11 32764. 0.752 0.087 0.00 7180. 10. 12 420.12 32835. 0.754 0.088 0.00 7190. 10.40 420.40 34889. 0.801 0.106 0.00 7479. 10. 67 420. 67 36947. 0.848 0. 119 0. 00 7764 . 10.70 420.70 37180. 0.854 0.120 0. 00 7795. 10.71 420.71 37258. 0.855 0.121 0.00 7806. 10.73 420.73 37414. 0.859 0.122 0.00 7827 . 10.74 420.74 37493. 0. 861 0.125 0.00 7838. 10.76 420.76 37650. 0.864 0.128 0.00 7859. 10.77 420.77 37728. 0.866 0. 133 0.00 7870. 10.79 420.79 37886. 0.870 0.138 0.00 7892. 10.80 420.80 37965. 0.872 0.141 0.00 7902. 10.82 420.82 38123. 0.875 0.142 0.00 7924 . 11.09 421.09 40302. 0. 925 0.167 0.00 8216. 11.37 421.37 42646. 0. 979 0.185 0.00 8525. 11. 64 421.64 44988. 1.033 0.201 0.00 8828. 11. 91 421. 91 47413. 1.088 0.216 0.00 9136. 12. 19 422.19 50017. 1.148 0.228 0.00 9461. 12. 46 422.46 52614. 1.208 0.241 0.00 9780. 12.74 422.74 55400. 1.272 0.252 0.00 10117 . 13.01 423.01 58175. 1.336 0.263 0.00 10446. 13.29 423.29 61149. 1.404 0.273 0.00 10794 . 13.56 423.56 64109. 1.472 0.282 0.00 11134 . 13.84 423.84 67277. 1.544 0.292 0.00 11493. 14 . 00 424.00 69132. 1.587 0.297 0.00 1170' 14 . 10 424 .10 70309. 1. 614 0.762 0.00 1183" 14 .20 424 .20 71498. 1. 641 1. 610 0.00 1196. 14.30 424 .30 72701. 1. 669 2.710 0.00 120G ": . 14.40 424 .40 73917. 1. 697 4.010 0.00 1222� . 14 .50 424 .50 75146. 1.725 5.480 0.00 12360 . �4 . 6C 424 .60 76309. 1.754 6. 910 0.00 1249� . 14 .;� 429 .7C 7?6�5. l.?�2 7 . 4'-_� �.00 12629. O 2013 D. R.STRONG Consulting Engineers Inc. Page 35 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2013 14.80 424.80 78915. 1.812 7. 930 0.00 12765. 14.90 424.90 80198. 1.841 8.400 0.00 12901. 15.00 425.00 81495. 1.871 8.840 0.00 13038. 15.10 425.10 82806. 1. 901 9.260 0.00 13176. 15.20 425.20 84130. 1. 931 9.660 0.00 13314 . 15.30 425.30 85969. 1. 962 10.040 0.00 13953. 15.40 425.40 86821. 1. 993 10.410 0.00 13593. 15.50 425.50 88187. 2.025 10.760 0.00 13734. 15.60 425.60 89568. 2.056 11.110 0.00 13875. 15.70 425.70 90962. 2.088 11.440 0.00 14017. 15.80 425.80 92371. 2.121 11.770 0.00 14160. Hyd Inflow Outflow Peak Storage Target Calc Stage Elev (Cu-Ft) (Ac-Ft) 1 1.88 ******* 0.28 13.49 423.49 63386. 1.455 2 0. 93 0.31 0.25 12.72 422.72 55199. 1.267 3 1.12 ******* 0.22 11.94 421. 94 47731. 1.096 � 0. 93 ******* 0.22 11.94 421.94 47716. 1.095 5 0. 99 ******* 0.16 11.05 421.05 39968. 0. 918 5 0.58 ******* 0.10 10.23 420.23 33669. 0.773 ? 0.76 ******* 0.06 9.39 419.39 27883. 0.640 8 0.82 ******* 0.06 8.21 418.21 20902. 0.480 ---------------------------------- R.cute Time Series through Facility Inflow Time Series File:dev.tsf Ostflow Time Series File:rdout Tnflow/Outflow Analysis Peak Inflow Discharge: 1.88 CFS at 6:00 on Jan 9 in Year 8 ?eak Outflow Discharge: 0.280 CFS at 14:00 on Jan 9 in Year 8 ?eak Reservoir Stage: 13.49 Ft Peak Reservoir Elev: 423.49 Ft Peak Reseraoir S�oraae: 63386. Cu-Ft . 1.455 Ac-Ft Flow Frequency Anaiysis Time Series File:rdout.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 0.251 2 2/09/O1 21:00 0.280 13.49 1 100.00 0. 990 0.064 7 1/07/02 4:00 0.251 12.72 2 25.00 0. 960 0.217 3 3/06/03 22:00 0.217 11. 94 3 10.00 0. 900 0.061 8 8/26/04 7:00 0.217 11.94 4 5.00 0.800 0.095 6 1/08/05 3:00 0.163 11.05 5 3.00 0. 667 0.163 5 1/19/06 0:00 0.095 10.23 6 2.00 0.500 0.217 4 11/24/06 8:00 0.064 9.42 7 1.30 0.231 0.280 1 1/09/08 14:00 0.061 8.21 8 1. 10 0.091 Ccmputed Peaks 0.270 13.2i 50. 00 0. 9�0 Flo:�� ura�io� frcm ,_rr.� Ser_�s F=_=e:r��Lt.tsf C 2013 D. R. STRONG Consulting Engineers Inc. Page 36 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31, 2013 Cutoff Count Frequency CDF Exceedence Probability CFS � a $ 0.004 37253 60.752 60.752 39.248 0.392E+00 0.011 2181 3.557 64.309 35. 691 0.357E+00 0.018 2049 3.341 67.650 32.350 0.323E+00 0.025 2774 4.524 72.174 27.826 0.278E+00 0.032 2761 4.503 76. 676 23.324 0.233E+00 0.039 3214 5.241 81. 918 18.082 0. 181E+00 0.046 3815 6.221 88. 139 11.861 0.119E+00 0.053 2842 4.635 92.774 7.226 0.723E-01 , 0.060 1950 3.180 95.954 4.046 0. 405E-01 0. 067 1952 3.183 99.137 0.863 0.863E-02 0. 074 34 0.055 99.193 0.807 0.807E-02 0.081 20 0.033 99.225 0.775 0.775E-02 0.088 43 0.070 99.296 0.705 0.705E-02 0.095 57 0.093 99.388 0. 612 0. 612E-02 0.102 44 0.072 99.460 0.540 0.540E-02 0.109 51 0.083 99.543 0.457 0.457E-02 0.116 51 0.083 99. 627 0.373 0.373E-02 0.123 34 0.055 99.682 0.318 0.318E-02 0.130 9 0.015 99. 697 0.303 0.303E-02 0. 137 6 0.010 99.706 0.294 0.294E-02 0.145 10 0.016 99.723 0.277 0.277E-02 0. 152 12 0.020 99.742 0.258 0.258E-02 0. 159 19 0. 031 99.773 0.227 0.227E-02 0. 166 19 0. 031 99.804 0.196 0.196E-02 0.173 15 0.024 99.829 0.171 0. 171E-02 0.180 14 0.023 99.852 0. 148 0. 148E-02 0.187 7 0.011 99.863 0. 137 0.137E-02 0.194 12 0.020 99.883 0. 117 0.117E-02 0.201 9 0.015 99.897 0.103 0.103E-02 0.208 10 0.016 99.914 0.086 0.864E-03 0.215 10 0.016 99.930 0.070 0.701E-03 0.222 16 0.026 99.956 0.044 0.440E-03 0.229 10 0.016 99.972 0.028 0.277E-03 0.236 4 0.007 99.979 0.021 0.212E-03 0.243 4 0. 007 99.985 0.015 0.147E-03 0.250 6 0.010 99.995 0.005 0.989E-04 Duration Comparison Anaylsis Base File: predev.tsf New File: rdout.tsf Cutoff Un�ts: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New oChange Probability Base New °Change 0.069 I 0. 94E-02 0.83E-02 -11. 6 I 0.94E-02 0.069 0.066 -4 . 5 0.088 I 0.62E-02 0.70E-02 13. 1 � 0.62E-02 0.088 0.095 7 . 4 0.107 I 0. 49E-02 0.48�-02 -1.3 � 0.49E-02 0.107 0.107 -0.3 0.126 I 0. 37E-02 0.31E-02 -16.4 I 0.37E-02 0.126 0.117 -7. 0 0. 145 � 0.28E-02 0.28E-02 -2.3 � 0.28E-02 0. 145 0.142 -1. 6 0. 163 I 0.22E-02 0.21E-02 -7.4 I 0.22E-02 0. 163 0.160 -1.8 0. 182 � 0.15E-02 0.15E-02 -1.1 � 0.15E-02 0.182 0.182 -0.3 0.201 I O.10E-02 O.10E-02 1.6 I O.10E-02 0.201 0.202 0. 6 0.220 I 0. 62E-03 0.49E-03 -21.1 I 0.62E-03 0.220 0.217 -1. 5 0.239 � 0.34E-03 0.18E-03 -47.6 I 0.34E-03 0.239 0.226 -5.2 0.257 I 0.21E-03 O.00E+00 -100.0 I 0.21E-03 0.257 0.238 -7. 5 0.275 � 0.16E-03 O. OGE+OC -"�_00. 0 � 0. 16�-03 0.276 0.243 -12. i v 2013 D. R. STR�NG Consulting Engineers Inc. Page 37 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31, 2013 0.295 I 0. 11E-G3 C. 00�+CO -1�0.0 ' 0. "_lE-�3 0.295 G.246 -16. 5 0. 314 � 0. 16E-04 O.00E+00 -100.0 I 0.16E-04 0. 314 0.25i -19. 9 Maximum positive excursion = 0.007 cfs ( 8. 6%) occurring at 0.081 cfs on the Base Data:predev.tsf and at 0.088 cfs on the New Data:rdout.tsf Maximum negative excursion = 0.063 cfs (-19. 9%) occurring at 0.314 cfs on the Base Data:predev.tsf and at 0.251 cfs on the New Data:rdout.tsf ---------------------------------- Route Time Series through Facility Inflow Time Series File:dev.ts{ Outflow Time Series F_le:rdoi� Inflow/Outflow Analysis Peak Inflow Discharge: 1.88 CFS �t 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.280 CFS at 14 :0� o� Jan 9 ir_ Y�ar 8 Peak Reservoir Stage: 13.49 Ft Peak Reservoir Elev: 423.49 Ft Peak Reservoir Storage: 63386. Cu-=t . 1. 455 rc-F� Flow Frequency Analys_s Time Series File:rdout.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 0.251 2 2/09/Ol 21:00 0.280 13.49 1 100.00 0. 990 0.064 7 1/07/02 4:00 0.251 12.72 2 25.00 0. 960 0.217 3 3/06/03 22:00 0.217 11. 94 3 10.00 0.900 0.061 8 8/26/04 7:00 0.217 11. 94 4 5.00 0.800 0.095 6 1/08/05 3:00 0.163 11.05 5 3.00 0.66� 0.163 5 1/19/06 0:00 0.095 10.23 6 2.00 0.500 0.217 4 11/24/06 8:00 0.064 9.42 7 1.30 0.231 0.280 1 1/09/08 14:00 0.061 8.21 8 1.10 0.091 Computed Peaks 0.270 13.21 50. 00 0.980 Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS a °s % 0.004 37253 60.752 60.752 39.248 0.392E+00 0.011 2181 3.557 64.309 35. 691 0.357E+00 0.018 2099 3.341 67.650 32.350 0.323E+00 0.025 2774 4 .524 72.174 27.826 0.278E+00 0.032 2761 4.503 76.676 23.324 0.233E+00 0.039 3214 5.241 81.918 18.082 0.181E+00 0.046 3815 6.221 88.139 11.861 0. 119E+00 0.053 2842 9 . 635 92.774 7.226 0.723E-01 0.060 1950 3. 180 95.954 4.046 0.405E-01 0.067 1952 3.183 99.137 0.863 0.863E-02 0.074 34 0.055 99.193 0.807 0.807E-02 0.081 20 0.033 99.225 0.775 0.775E-02 0.088 43 0.070 99.296 0.705 0.705E-02 O 2013 D.R.STRONG Consufting Engineers Inc. Page 38 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2013 ---, 0.095 57 0.093 99.388 0. 612 0. 612E-02 0.102 44 0.072 99.460 0.540 0.540E-02 0. 109 51 0.083 99.543 0.457 0.457E-02 0.116 51 0.083 99.627 0.373 0.373E-02 0.123 34 0.055 99.682 0.318 0.318E-02 0.130 9 0.015 99.697 0.303 0.303E-02 0.137 6 0.010 99.706 0.294 0.294E-02 0.145 10 0.016 99.723 0.277 0.277E-02 0.152 12 0.020 99.742 0.258 0.258E-02 0.159 19 0.031 99.773 0.227 0.227E-02 0.166 19 0. 031 99.804 0.196 0.196E-02 0.173 15 0.024 99.829 0.171 0.171E-02 0.180 14 0.023 99.852 0.148 0.148E-02 0.187 7 0.011 99.863 0.137 0.137E-02 0.194 12 0.020 99.883 0. 117 0.117E-02 0.201 9 0.015 99.897 0. 103 0.103E-02 0.208 10 0.016 99.914 0.086 0.864E-03 0.215 10 0.016 99. 930 0.070 0.701E-03 0.222 16 0.026 99. 956 0.044 0.440E-03 0.229 10 0.016 99. 972 0.028 0.277E-03 0.236 9 0.007 99. 979 0.021 0.212E-03 0.243 4 0.007 99. 985 0.015 0. 147E-03 0.2�0 0 �.0"'-0 99. DURATION ANALYSIS N � fdOULduf O R targetdur • m 0 v d 0 � 0 � U N � m � �y O L U � N O � O W O O O O l0 5 � � ��0-0 � 10 3 10 2 '10 � 10� Probab�:ity F�ccer'ence G 2013 D. R.STRONG Consulting Engineers Inc. Page 39 of 39 Stormwater Pollution Prevention Plan Piper's Bluff January 31,2013 � y � 1 PUBLIC WORKS DEPARTMENT p �� •�f�O� �� M E M O R A N D U M DATE: September 25, 2013 TO: Jan 111ian, Plan Reviewer Dan Thompson, Construction Inspector FROM: G2�on Straka, Surface Water Utility Supervisor, x7248 STAFF CONTACT: Hebe C. Bernardo, Surface Water Utility Engineer,x7264 SU6IECT: Piper's Bluff—Bay SaverT'"Adjustment 2013-04 The Surface Water Utility has completed review of the adjustment request from WestPac Development LLC for the Piper's Bluff Subdivision in accordance with City adopted 2009 King County Surface Water Design Manual (KCSWDM) and City Amendments to the 2009 KCSWDM. Our review of the information leads us to understand that the applicant's engineer is requesting an adjustment from the 2009 King County Surface Water Design Manual to core requirement#8) Water Quality. Our review of the information provided by the applicant engineer on October 16, 2012, provides the following findings: 1. The projed went through drainage review in 2012-2013. Plans were approved for construction in May 2013. The projed is currently under construdion. The construction permit number is U13000618. 2. The projed was originally approved using Contech Cartridge system for basic water quality treatment mitigation, per City adopted standards. WestPac Development is requesting a substitution of cartridge systems(from Contech Cartridge System to Bay Saver'" Cartridge System) due to Contech's inability to meet the production schedule. The adjustment request proposes to use the Bay Saver'"' Cartridge System for Basic Water Quality treatment. The Washington State Department of Eco(ogy has approved the Bay SaverT"" Cartridge System'"'for General Use Level Designation for Basic Water Quality treatment. Based on the information provided in the adjustment request,the Bay Saver"" Cartridge System for Basic Water Quality Treatment is approved with the following conditions: . � . < Ms.Illian Page 2 of 3 September 25,2013 1. The as-built.construction plans that are prepared following the completion of the project construction are to be updated to include the details and information associated with Bay SaverT"' Cartridge System that is being installed instead of the Contech Cartridge System that was shown on the approved construction plans. 2. The water quality design flow shall be as listed in the General Use Level Designation for Bay SaverT"" Cartridge System. 3. The Storm Filter system shall be sized as described in the Bay SaverTM' Cartridge System '"'Technical and Desiqn Manual, and the designer shall select the result yielding the larger number of cartridges. 4. Pre-settling shall be provided per Section 6.5.1 of the 2009 KCSWDM, General Requirements for Media Fi(tration Facilities. 5. The Bay Saver�"" Cartridge System must be instalfed in an area that is accessible to maintenance equipment. The maintenance of a Bay SaverT" Cartridge System requires a vacuum truck as well as the removal and replacement of the filter cartridges. The manhole covers, and/or access openings of the Say SaverT"" Cartridge System must be placed in locations that can be easily reached by such a vehicle. 6. Facility shall be constructed in accordance with the plan (attached}with the 36- inch and 30-inch manhole access opening with ladders in both access openings. 10. Installation of a eay Saver'" Cartridge System shall follow the manufacturer's recommended procedures. 11.The Bay Saver'"" Cartridge System shall be inspected every six(6) months during the two-year maintenance and defect bond period following completion of construction and plat recording. The owner is responsible for the maintenance of the Bay SaverT" Cartridge System during the two-year maintenance and defect bond period. 12. All Bay SaverTM' Cartridge System cartridges will need to be repfaced before the end of the two-year maintenance and defect period, prior to release of the of the two-year maintenance and defect bond. The City will maintain the facility after the two-year maintenance and defed bond is released at the end of the two-year maintenance and defect bond period. 13. The Bay Saver"" Cartridge System shall be maintained in accordance with manufacturer recammendations. H:\File Sys\SWP-Surface Water Projetts\SWP-27-Surface Water Projects{CIP}\273129 Rentan 5tormwater Manual\ADJUSTMENTS\2013\2013-4-Pipers Bluff-Bay Fi(ter.doc\HCBtp Ms.11lian , Page3of3 September 25,2013 14.The Bay Saver'"" Cartridge System shall be installed in accordance with the approved construction plans at the same location of the previously approved Contech Cartridge System was proposed to be installed. 15.The approval of this adjustment to use the Bay Saver'"" Cartridge System for the Pipers Bluff Plat does not authorize the use of the Bay Saver'" Cartridge System on future projects without prior approval from the City of Renton. 16. Please note that the approval of this adjustment does not relieve the applicant from other city, state, or federa[ requirements. If you have any questions about this adjustment, please contact Hebe C. Bernardo or me. Attachments tt: Lys Hornsby,P.E.,Utiiity Systems Director Neil Watts,Development Services Director Richard Marshall,Surface Water and Water Maintenance Manager file H:\Flle Sys\SWP-Surface Water Projects\SWP-27-SurFace Water Projects(CIP)\27-3129 Renton Stormwater ManuaI�ADJUSTMENTS\2013\2013-4-Pipers Bluff-Bay Filter.doc\HCBtp BAYSAVER � TECHNOLOGIES° Piper's Bluff City of Renton, WA Stormwater Management BayFilter System BayFilter Sizing Report Prepared by: BaySaver Technologies, LLC Paola Rodriguez (301) 829-6470 prodriguez@BaySaver.com 1030 Deer Hollow Drive Mt. Airy, Maryland 21771 r Table of Contents 1.) Overall System Design 2.) BayFilter Design Computations 3.) Bayfilter System Details , i.) Overall System Design: This is a proposed design to the SWM Plan for the Piper's Bluff project. The current design employs an underground Contech Stormfilter system for treatment of the WQV flow rate of 0.101 cfs generated by the site. This system utilizes a 96" diameter manhole with 13 stormfitter cartridges. We are proposing a treatment solution as an alternate to the aforementioned system with a Bayfilter Filtration system. The BayFilter system wil) consist of an 84" diameter manhole with 3 Ba�lter cartridges to treat the required WQV flow rate. Each BFC has a design capacity of 15 gpm, as approved by Washington DOE. 2.)BayFilter Design Computations Flow Based Sizin Calculator Ba Filter Re uired Treatment Flow cfs 0.101 � Flow Rate Per Cartrid e m 15 I Number of Cartrid es Re uired 3 �� Treatment Flow Provided cfs 0.10 ' Precast Structure Re uired 84"-MH I�I Flow Based Sizing Calculator 1 Computed Treatment Flow(cis) 0.101 36' FRAME ao' FRAME Flow Rate Per Cartridge(gpm) 15 � a2s oo a2s oo ER Number of Cartridges Required 3 Number of Dreindown Modules Required 3 ' , Treatment Flow Provided 0.10 N�� Vault Required 84-rnh ' .� IAYFILTER STORMVATER F0.TRATIOI STSTEM PROTECTED!Y US.PATENT M 6,869,328 e � - S� e �.. '1. o 0 18' OUTLET '`� � � � o 18' OVER��OW STANDPIPE 30' FRAME � � 6 COVER e e ;� -----84•----- ;�. �84` �': o � `�, ;� � � .� �� t8' OVERFLOW '� STANDPIPE 36' FRAME �� 6 COVER � ` ` � � 18' INLET �, O O 410.00' 18' OUTLET 407.70' - =.:•'...�. ': :�;j ::;. '.� �� ' .�::: ,i:�. 18' INLET PLAN VIEW SECTION VIEW REv DESCRIPTION a►rE ra�s: �I3AYSAVER ILGINOLOGIES o� Pe� c��y oi Ranton, odd.a seoa,d y/»��3 h00-829-7283 ' monhole acceea. `r ,v'AWtlAVSAVERCOM gAYFILTER MANHOLE DESIGNED: TEP DATE: 9/17/13 MODEL MHF-84-3 DRAVrh PR SCALE: N.T.S, CHECKED: EKH DWG Na HF-103 BayFilter Installation Instructions P[PER'S BLUFF—RENTON, WA ', MANIFOLD AND STAND P�E PICTURE I� :,z= _ ,. .::� _ __ - _� .. __ ._ - . _� - � � � _ - • - �}- _ � , . _ - �, -;�= = - _�.,_- � � 4 . �� ,.;� u,�. � �� .� _ �.� � �-� � = � �__ ' ; � _��_ ,'�� r---,' �e ,� -�, ��'�� `.=l��i -� �� - Q �� L �.��; -�� ,� �� -� - - _ - : . <_-' �� ' .� _ �. - � � : r - • -. - �- ...:_ r. _: - �i, _:. .. : . _.._>�.. - �:- ��" _ _ �-.___A...�.�,_,_._ :� SEE ATTACHED DETAIL DRAWING FOR ASSEMBLY HAYFILTER STORMVATER FILTRRTION SYSTEM PROTECTED HY U.S.P�TENT � 6,B69,S2B 18" �UTLET 1 18" �VERFL❑W STANDPIPE � BAYFILTER MANIFOLD ASSEMBLY � , e� . 1. One (1 ) 18" overflow standpipe. � � � ��.:: , . 3 2. One (1) 4" fernco. ' � 3. One (1) 4" pvc pipe 6" long. ' � 4 4. One (1) 4" pvc cross fitting. . 5. Two (2) 4" pvc pipe 15" long. . �� 6. One (1) 4" pvc pipe 20" long. 7 .~' 7 7. Three (3) 4" Filter Tee fitting. 8. Three (3) Flow disks 1.14" orifice. :. 9. Three (3) 4" insert caps. 1 Q 10. Three (3) Draindown Modules. g � 11. Three (3) Bayfilter BFC cartridges. . 9 ., . 9 :� ' �� , � 10 . a. . 3 " �84" 11 7 36" 18" INLET 18" OVERFLOW STANDPIPE R�v o�scRiwr�on� o�� P NOTES: � 13AYSAVER rr•cHNoi.ocirs , f. BFC carM�Edges a�.d �r R00-829-7283 PIPER S BLUFF wwwpAYSAVLN.COM BAYFILTER MANHOLE DD1!'s shti�ped j'ram ADS pEc.�GNED: TEP ��n: 9/ll/13 MODEL MHF-84-3 warehouse. DRavrx PR scn�: N,r.s. MANIFOLD DETAIL CHECKED: EKH DVG ND� HP--103 BayFilter Installation Instructions Installation of a BayFilterTM System 1. Contact utility locator to mark any nearby underground utilities and make sure it is safe to excavate. 2. Reference the site plan and stake out the location of the BayFilterTM manhole/vault. 3. Excavate the hole,providing any sheeting and shoring necessary to comply with all federal,state and local safety regulations. 4. Level the subgrade to the proper elevation. Verify the elevation against the manhole/vault dimensions,the invert elevations, and the site plans. Adjust the base ag8regate, if necessary. 5. Have the soil bearing capacity verified by a licensed engineer for the required load bearing capacity. On solid subgrade,set the first section of the BayFilterT^t manhole/vault. 6. Check the level and elevatian of the first section to ensure it is correct before adding any riser sections. ?. If additional section(s}are required,add a watertight seal to the first section of the BayFilterTM manhole/vault. Set additional section(s)of the manhole/vault,adding a watertight seal to each joint. 8. Install the trolley system(if applicable). See separate instruction sheet. 9. Install the PVC outlet manifold. Glue all PVC joints with the exception of the BayFilter cartridge coupling. See separate insuuction sheet. 10. Install the PVC outlet pipe in BayFilterTM manhole/vault. 11. Install the inlet pipe to the BayFiiterT"'manhole/vault. 12. After the site has stabilized,remove any accumulated sediment or debris from the vault and install the Ba�lter Drain Down Modules(DDM}with red mark aligned to the top of the manifold system. 13. Install the flo�v disks and the BayFilterT""car[ridges. TOOL LIST: � • PVC GLUE AND PRIMER • CRANE/LIFTING MECHANISM TO LOWER THE CARTRIDGES IN THE VAULT(EACH CARTRIDGE WEIGHS 350 LB) • SCREWDRIVER OR NUT DRIVER FOR FERNCO COUPLERS • SOFT BLOW HAM1v�R • SAW(IN CASE PVC SCH 40 PIPING LENGTH NEEDS TO BE ADNSTED). GRANITE PRECAST Up To Center/Up Calculatlo Job: 7101 Customer. BAYSAVER 7ECHNOLOGIES,INC. 5trvcture Code:84' Type: Storm ' I Job Name: PIPER'S BLUFF Statlon:REVISED Descriphion: 84"General Storm R Unit Structure Product Detail Inside Area View kem_ Product a�Product Deser�gtion Yards Waight �{m to Invert 17.30' Preqst Height 17.25' Wall 8.00" CR-06X3 1 8'X 30'GRADE RING 0.00 300 Less CasU�g 18.97' Floor 7.00" Sum 0 CR-04X3 1 4'X 30'GRADE RING 0.00 220 p I C.CUST 1 4'x30•CI RING AND CI COVER o.00 o Invert to Floor 0. Plus RoOr 17.83' LOCKWG'DRANI" AdJustrnent(Brick/Mort) 0.14 C.CUST 1 45c38'CI RING AND CI COVER 0.00 0 • LOCKWG'DRAIN" �,�, ._.._.___._.._.._.._.._.._, g� Too 2 CR-04X3 1 4"X 38'ORADE RING 0.00 82 T�q 1.42 84"CUST�OM FLA�T�TOP/ Too 4 084TS2R 1 84"CUSTOM FLATTOP/TW O ROUND 2.18 8.700 HOLES � Tou 3 CR-08X3 1 6"X 38"GRADE RING 0.00 400 ttem 2 084XQ7R 1 84'X T RISER 4.20 18.800 ��2 T.00 84"X T RISER kem 1 OB4X08R 1 84"X B'RISER W/HOLE 4.84 18.580 Base 0849S 1 94"BASE SLAB x O.SB' 1.88 7.340 Acces 084RG 3 84"GASKET 0.00 0 SVucture Totals 12.90 52,602 ' Hem 1. 2 8.00 84'X 8'PoSER W/HOLE � 1 Elevations 3so 2m �eo � � so 0�,0° Ekv Angb Plpe Hde Mole' Hole' Up' Ilem Im _1.�_ --- TYVe Nei9M Width . I(Il �? L� e Pv ___� _S�Q� _ 1�.1 _ll�r�t I �L2)_._ . .'_ 410 .�.- y�--.- -� --�QRE-Q- _ 2 _�4 1 Itemt_ � �3)--- � - - �---- ----- -�-- - -----_ �. -� - � --- (4�-...:--- - -�----�.. .- -�-- - - �-- .Q. — - (5)____: _ _ 0_ _. ______. _ o_ . _ 0 ,._ o NEEDS CUSTOM 2 HOLE TOP SLNB.SEE AITACHED. le)_ .: �_ o__ ._ _._..�_._. --, o-- 9. . 9_... �_ _.` � o 0 (eL__. ..- -�---- '- -- o 0 0 DexAptlon: 84"X 8'RISER W/HOLE Product ID: 064XOCRWC Nem: Item t Slep Location: D011 (1�ORED M I , UP:14.1" / �JO }k�l.{� 135 I v APPROVQL OF DRAWING THIS DRqWING�9 FURWARDHD FOR YOURAPPROVAL. ' �G'��^��, PLEASECHECNTHEDRAWINGAMDRETURNITAPPROVED 'i �� OR WiTH CWINGES NOTED,IFANY. S�pb ARODUGTlpN W►LL NOT START UNTlL APPROVEp DRAW/NCSARE RETURNED. (2�ORED COMPANY Up:41.7" !Mg 315 � Meets or Exceeds WSDOT Std Plan B-15.60-01 iB 4" Typ e 3 Ma nhole Manhdes Canstructed in Aaordance Wlth ASfM C-478 Rubber Gasket Canforms to ASTM C�43 Polyprapylene MH Steps Conform to PSTM C-478 �1�in , , �4��I.o. CUSTOM ER: BAYSAVER i� � PROJECT: PIPERS BLUFF . . •- �� .� DATE:9/16/13 // \� J��+ �� 5 J O gS30 In Access Z g� Z W a� �� 36 in Aaess \\ // `� ti �� .� a�� Q PLAN �°� ''Q I � Y,4`,6',w12' LLw��Zy �''I Grade Rinp Q��LL�Z J�� : Z ---L—L--- 1 U��z�o 8�, ------- �;c� U� � ,�� WU�O o i a��S�Q a � DETAIL E � �' I �F��4 Q � � k SCALE 1 / 24 .�,,,� I r to 8' ------�_� c� I I �� WEI6HT5: J.,.a TOP SLAB: 12"- 8,700 Ibs � I RISER: 1'- 2,400 Ibs ; I� 2'• 4,800 Ibs �—————��T 3'- 7,200 Ibs I 4'- 9,600 Ibs ———— 5'- 12,000 Ibs �`` ' � E 6'- 14,400 Ibs 7'- 16,800 Ibs � o I 8'- 19,200 Ibs � I BASE SLAB: lY- 7,540 Ibs COIVCRETE: �,,, f Fr-4,000 psl�28 Days 1,��, REINFORCING STEEL: .d... � �� Wekled Wire Fabrk:ASTM M97 � I Rebar.ASTM A615 Grade 60 Top Slab:0.75 Sq In,/R.e,w.min. Riser:6.215q In./R e.w.min. 8� I Base 9ab;0.34 Sq In./tt e.w.min. PIPE PENETRATIONS: �.� —�L�� 1'Base Slab Ma�dmum Hole Size:72" Minlm�an Dis�nce Hole to Hole:12° Hdes Cored to Plan Spedf�tlons 8" 7' 8° Kor-N-Seal ConneGlons AvaNabie 8�� SITE PENEfRATIONS; Cor#ract�to Estadsh Level Grade ELEVATION VIEW Prlor to Setting ease Plece at a Talerar►ce of 1/4"Oo 3/8' �2013 Granite Precasting&Concrete,lnc, i��- - Ga G�A ITE � aRECfaST 4>>s e�xEnwEw�Pu+.a�anu�ws�.ww ssa�6-t3eo�e��ae�-�-soaana.aas�-P/►Xi(8e0I 671-07R0 -�,.�,..�'� , NE 1/4 SECTION 10, TOWNSHI� 23 N, RANGE 5 E, W.M. ; �� . E�s� � � �;; � <<.:a ��,.. _ ., P/ R S BL,UF n��A„� ,� , .y_ ,� ,:��==a� -_ --- -- ,,,.;,{. � .� ,��.� I°E ' F ��. � �� ,A„� � �- , UY MNi1tF 4F.�A_<t3JE�T).5� f/�.11 �IA 7 .. , � ♦ �'rnn I . - .. ..'-� _._ , � I I IN !S 70./1 '1 STA 1 0.Y R :�`Q (L� _ __.^ 1 l_ )P I ' � ,.:SV��LTd18 3 �, - ' [P J MEI vt 5 - _ � �. �%I �I J,,, ._.Iv:t+� . .. . , : . ' . . .. .:. . L P�,� ��,z.� .. .a . �� _: �o;--�'-� � � , .; . � . . .. , . . �T Y� �-�- : C9., hPf �-B i_IA .J�':.(Si -^.:7 �/', I �'.i � . ' . lill L _ !\�� i ' S... . � ...... • OA . �.R- ��. � - "�5a• I�_ L_ �FCd QFTAR.i SEE I,y�ET L71 FlM aE7AL5-'�.�.I . •, ��I' �� i)Frhzr��as�.sr�t- . ..�� , :. �_'.� _- . ._ ` _.. -- - ---- �� --- --- _ . , . �, p k✓ _ � �I � � ..� ., .,,,�r. '.I _ - = --�--- cr--___... .. �{ .� � .� _"--"�� '- - -- __ -- _ - - - '.- -- � ' - - -'fi--- N X�� = . -- � -.':"-. - . � �-- - - -- _ - � "�x , -, - - °'"-aE�st '.' .-...�a�-� :^� . .. . .. - ...- - - � - _ c -- > __.`:�e - - -- �� .. ..ai - � _- . , _ T- _. .. � _ �l' �� ,a-� � I - � �oz�B �l .r,.�a� �f- . ; : r . I ..., -. ,- - -- x - - - � � - - - da* .. _ ./ i. s,z rafaa� ^uc R ` �I�OOUTA�'i4[NE� �� , � - � -._ _ � r_ _� - - .. � '1� \� :11:_._... �2-i.ayi3_n�C_c, - ;�� . '� •,� - _� ��- __� -_� - - ... _ _ - _ -''v :� �\ . - - :_ ::fi. ;"-----� . . w E .. � I - � �� . _ . -+ __ . . � � �-� J/ ,. � ., ._ � ,.. .. :, - _ � .,. �-�.� \ \� '_ . Y�_. -�� .K�_-rf -�:� � Z �L ' :a7"'SNC -�� I � :�- I'. "�. . _" � UAI�E9IT� �29 � Lg7E� ��' � � `��.� � ' " _.-_'Y.�-_'-q. T /� sa��uK•MiH cw�c v � ��u�a � . j!_ � � _ � .s� / �� •�. . _ uJ �.r+n con sa.�'n I � `� � ��-� I: � .. "� . � � s.�. c w / I , . I(239 H,�:�:. ��I.Z0.f3� .\. , et� ]F N � �] i��C'S^ CUIVCR�-�� { �Y' . ._..... m� azY i �-�[� . f��XeF �� i� -as�.s3 / :�i � I � 2 3 -4 � � ' . � - - . . � � .c.�.r nxrc a cu�c.c,.«1-� � f� . _, 5 6 >. . � �� - • � �e .ss.s� , � � I 7 JI + �� + . - t - TRA�E�T 8".�- � \ �i � V I J � Q£ARA/IfF I W p��a.saoi �� ,�' ,'� _,.I . _ _. A •uwrrmvr.. , QI " i ..• - - �� w n.o-rf.`n�� ` • I Q_, .� a ��v�r.�r+7� >.�.r I Il - � \ ..r `. vi[r � ��,\ � c .�,c�sl_ �syr s+�" �� t I _�_ � ,��= - � �1 - � �.`� I11 I�. i �I � y€�ean�oc-�Fei�� ,4� ,irW E t l�'N! a5.]J ' j' � I` I'-� - - (1 J7 , . I � ' STA 16+H.lEI \ �PAl£D � �l��`�',�\ 'C(TIG CLI`filiT� � q J.. I�'� _ 1 �•L � ♦ � � I � '6f R' YaG�AGI�uy1 �-♦ a�\` _ 8.P3 I . � ___ _ _ �_ -_ �•�. . � 5 ��. � �� u ALLEY'4" �n� u � I. � � �wF � o�ca� � �Y P, M1� I, � I . ,� �. �� r� � T^:`� - � -.�-- - - �- � .g I I i I �� ,. ,\ �; ., w^Y.CJLK" I k,. , i � I �•�:� � �. ..i ��.1 - �F � � � �.i � � ` `� ; � ;�-r�no+a�u� `��, F- 58.�. y ."CRIW.F7�L..'_ I A Z/ ��:I. _� I . - ' ' �� A • I7 �� -'� , �'�-•' •� . I �` I I� . // � � r'� ,�FhYi1�D74'!C -1�� ii " � �. '� * ` �. e��e �,l!.cRi � !UAlT'E91T 00 . I . , , f'^'_ F . �57..7E I . .. . 'I iXl . L A:1 IQ.11.6l7 C T 1' - ,� ��, ' -POYD NN£I i "W F � �u asasT !B'PHIVATE ACC63 TR.4CT A" ') rc auoo wce ir��i-� ,Z _..I,;; 16 : � ¢ue.Si� uw . i .. $- � i�srorwsewrw��arov� m _ i,». � 4 .,- - -- :M- s62.19 I W ��i' >n nc>� 15 , �:r ,�. -- , i�iti ca;��u;�+6e� �, e ��, [ I '' '� � 13 12 � 11� � � I anne . J-�.��,' c _ �:CHC(51-�_45n ' � , � �, �� "` 1<�� AMI$��F: II _'�•�•t_ � �� -�%91FE7 CI ��-�. �._ ' ;.�,�. � a. IO2,N:S4i51 'Q-.�'�Y TA�IOa 8171 � . .. . -_ '__ � _ •1 1. I ' -� � - � � I` I ..I-: . . . � �g � � i � i. _ � �� ,.�.� ;, ,q r . �7�.:�It1C�lEU P_�<R' , .J..O I�I . . .. L MAQ� .M1 1 ) I - 57CYPY DEiEN77(MI PCYAD � 'a.t-�i' Q ' - - � __ . z.., 5 � D �� r _ r - - �,. � - �,��_�.,.��. _�$ �9 � / � �� 1� OET.MJL�PR0�91ED�7i.1.xf Gf. ._' _ _ __ _ '_ t � ' A. - - � - _.-_ �-�Y�_� �- =- � _ � I - / � i � . - S'EE 9FFI,C7J AND 51Rl1C7UIP.1L I � f - � �I / I n.AHs!Ae oErMs r • 9�'nJ r+c - ., I' : �, .�, .. �'��-'� .'. •. � 1'. � � - ' � ' ;..:;: . . ,:_. ' , : . . ;.� :-.. � e�.c�v.�n-•:avn. �-1�.._ i IZ. '- �• �. �' . . ... _ ,.. .. . .:. .i.� _ / � -� ... . ��Axa�iro ��me�r�n� I' ,I .< - � rr � � _ � �� '�� -- `�e - - - - - --''c000wc.ca��r�caess � w�.. a, - . --P._ I � - � _. - _ �... - v , . . � >_� Arto�usMc we 'UlrE�7' _ '� .��,I a. .. - -_ ,. �_\_ _ ` _ - �Q�-A j . . _ /� ` LP/f POS l __ i 1 ��OUIBIYC PoP/2/�/G L1� _. ' } � '� � F ` I �' .` . .. . . r CP11fl�iE�7}P.) STA/0+/194 T7.! x S I �/ ,. ,_- � Y. _ _ r_ _ _ � .. M - � - _ • M � � h / .�� _uaur�syx � - -- -:� -. - ' � � ` ��f�.l -�.- - - _-�--. r=-_�--_ = --�- _ _ - __ __+_ -�- -_ �� \` ` j ��,: �.z � r ,- � 1 -�--, -�-- - _ - - ; :F i� �F � „ .. -.s �o•va,v��xwr � 1 '�Ew�D.r n� r a .,c i:=i n: ti . � -,x",i , unurr esur. �m. sr•i ca dn R r oaou a , TRACT C'�' ---- ---- --- MN!aar a�_�ur i uFcr s�w•rsaraaa an R srAwseg.ea aan a tsca�svc�ors 'ra�na��m+1�1 -#_"' _ � .'. I_ . � . . 77 AND 18� . 4iA/+V R I � vcN^:o..av�, --� - -� - I` 18 19 20 Zl 23 � �i� ' - �i ', i s•e r�,c 22 P�Q � :i . sr•rz+ . � 24 . 26 �. fB/Q " r T*:Y•� ORMVACf SIV6 A7 .....�.�.. "/pp/I6QI0 . 25 ' Z7--., .�R �� • , t ' WM.2[SQ°_YM �fF ISl.TO � A�Ik � . Y , ' . � C=+6 I.. ' /nP; " � �i7 15.2 7 � ' '\ . 1 . _ " . .. � . . . _ . j_ar _ __ '_ " . - � \\,y� . - -. -PR I�EpE 1 'MA/a�R . . . . 0 .R6 � . r� �i .- . s19.M :T .[yu � � - . � . .1 .�I ,. . . . \ Y' P�O�D SR�!ORANA� . . . . . � r. , . �'..l•. SK7EL O!7A�OI.YM1 Alf7If.E � • I - -' � . - . _ � � I•:. • , C_i_ , -� TD Cl'YlYEY QT57AC ORANAf� I�: : I {� •�GI!: .q:'. � . - ---._. .. ... � =5 _ . � f�[4L� � n.-ocr,., r.., - � � �,i. , , �,' fRCW SWM � .�d ' . - -- - - - . � ��1 -_c� __•_' .I• .. . _ _ , -. ��'� '.. / � cnc �.xx�;ui� - - tl� _ ._? I �' � •,iu,c�sc ,• �` . ar r� i, �,� � '�'� yyk� �`.. 9a�r�, . � '. ' - i i �,F . r, �, - � i � ' ✓.: .I ` rf� '.Ir _ 71a �.5'rR_L . . . �: I -__.. r c'Pi I 1Y L �...vowFv. I . . ! ,. ��:� .,I , I I I I .j I ! 'OIJU a:�A � .�r 1 IP-1� ,� I $F m 1f'JC �� ..fi�'M:1.'Y� � .� ..... I , :.�."CI:�'_ I I 7 �} /�/� �p/�/ I ^I 16�' I I /LOW VVNI!{VL. BMP NOTF• �'��r�„, I P�fl:;:l Yi '..� N K.��(. I "_ iztr .e j ,is.�.��.�. r�. i. I _ .__ _- .__ "__ '_ "_ _ _ i':'1•..n.�c�� __ ACL L015 MLL UM2E REW/C£D IAFERNWS SURFACf(j7EIXT 91P I It_.�._i�.ln 15n;�iti�'n I .41.FO �1 �(FEY/Y'70 1D1i I ; __""- .-_ "._ __' "._" __ .._ ..... __. ___ : I ...�. I � I � �.i �,�.. �. .E 1611TJ 7 I: - T LaT'm. ^:AP.�..1 iSf) _' MANtlNN/ALLOWABLf LCT fA;. I COT AREA��f.) YM1NM Afl.OWABLE � � � w�xNw�s�ac�ax ca^�lsrJ s�xwa�vs��x coae(sFj N07E• UTIUTY N07E• , s.�oe Jser i� vos Jaea cavmncra+sr�w.Pon�aE.v.c exrsrwc uw w r. wtnr sruu e[No a.xer ro,�aKur ncr�ss ro ae fxav Now.w�uvx�e nr z isss sen ie s�a.7 .�� R 3 E� ! 0, g rnau nro�io�s nur neur�r. w+�rca.:iruxzavr�u iounavs ar�rae ro mvsneveiraw. a � �ass a+n is uoz z�n N O RT H 2 77iE nJ,+9i.W.�RESR7198![Fu7'r:7.7ENAtiLE tY iAMASUPWC iY�rAN i�F 1AAL7 il" 4 Ieee 3115 20 1501 J3le - 1ne atr srutc er Re�rwse�e rar u�w�,w�or n¢ort�aut�raaunes cawsmucr[v VERTICAL DATUM.' " n�nw n+e m�cr'�' �sraav av.uv��ca�vmr ro eu�r arv cr�rrcw sc+�t s �sss J�n zi asan Js�s ��urriic scxe R ENC.M�ASS D�E fN7GP£TY O�iRAL7'1' MAL9 BB PER:m oF RfNrov Y£FnGL GWR2(K 6 {366 J125 11 ISW JJ75 `� 30 60 C .v1 SLMER IRpt'YAMAY 15 POf FlEID AMt£Y BAS.TD pV A801£W 71ML 7 (366 JI13 IJ �3W �,773 � „ S.ALL�ORAMI SNB-IX/7S 10�PIeYATQY 1NP'LN�E0. i 1 INCH=30 FT. 8 19d9 P97 T9 ISOC JS73 � 1.LOTS i-Td MA..U94E 9Nli�1�57RIG7ID 777 A MA,WI/M aPERNp/5 GOYFRAGE EOUK 9 I551 J{IJ SS I500 JJ7S DRAWINGS NOT APPROVED R TO 6Sl 6�EAdI GOT AFEA � s. rxow cavma evPs cavsnnicica an iar wu ec mrx�rm,wawr,vam,vm 10 3197 JB9B � "" "" FOR CONSTRUCTION UNLESS RECOMMENDED e �rn:w c«n mP,�er�w mr a�wvr " '�Z "� �� "S° "" STAMPED OR SIGNED APPROVED FOR PPRQ AL � 6. IHE CIfY M7l INK ACCFSS JO MSPECT nff f1.0�'GTINJMOL 6w'�5 7a 9E i1 1762 J47T SR 37TD f191 - CGWSINIMlID QV IlE LWS 716'iHl HE IK1lNE0 Q4 THE�ACE OF IiK FRi9L IJ l56Y ]112 B � �„� �nu.a�er��e s�aeu eaa+�cnaJs m eE awaurm s�ue-a��z BY THE REVIEWWG AGENCY i� ass� ��u •�� g �s �sea .Hv F Y R.JO�.. 16 �361 Js71 BY � g vu y• �" 1 RE\d'OOIYMIS 1 MA113 IWf 6.7t.t3 LRI wi�/'«� '� �I I I O.� OQ-20-�2 "6 �u aor�u si � D.R. STRONG �r �� ""` RENTON PIPER'S BLUFF � Cal 2 YYakYip Day�Belore Yw dp ❑ EvcwEErrs w.�nwERS.Xxn�Eroas `� a 1'8�0--^r`2�-.rj.�rJ o �_' D � �.h�.r,u.a.noi roah:.�w,wRnwv �"'� �'�� Or1iW ��ORM DRAINAGE PL�1N � ` ��y�Ra��y��{� �R�_.c, ortiez'xm F�as.ez�a�z� � PlcnrinS/Build'ng/°uClic Works Dept. � (D,Afi,t�D,OiLWA) ��NAL F'c ,,,,,,..yavaqm,,, ,,, REVISION B'.' DA�E �.PP4 """Cp1iC-' a 'W C8 18 � n�:. .�-��R�� a-tiNti�a ^ � _ _ ,, _ �,.�., , � - _ ,�� . 3 jt� � �;� I� 3 :�. � � ii illl ' x . .� �.��: ..a��..�... , .:...- ,.. .:.,�..:�. . ..�' . . ... : � � , o � ! � / � � . • 1 • � i . u-��..��sf � 6a�/F71 Ler -� ,r� . • - Kellv.kokesh@ads-piae.com � � _ � - � _ - - .� � . i ;�` ,E E � �� 3 '�` - i�; _ i ;:�€ ; �? $ `I� �� ;�S . .�..-�;`-=�-.,_�...:..-' i ` • Specification _ . WA DOE Approval Listing , . Installation . Operations and Maintenance � . _ � �� z��.�_ � _ _ - �� _ i�' ,�: Sj I:$ �? iii ' �, iF� i �=1 i� ;'t i�� : !f 'ii ii� '�� I: S�� i�:i ii ,:.� { �! �i� if� �{: BAYSAVER TECHNOLOGIES� INC. - [�LET W ATE � r+eoiA spia� Kt 26,00" - NEDIA SPIRAL k2 . {j'� IHIET DRAINAC£ O � - VLLJ narEain� - � �UTLET BRAINRGE HATERlAL —r"'I �—�,OO, �, - P�_YMER SEAL -- , � �J7�E? CHANBER i � OiJiL.ET PfPE � � n[R REIE�SE VALVE � FL�4 CakTRO� �RIFICE � � i ' ' z8, 5" � � r-_�TE� ��s i ___ �� OUTtEt �� '�. C�LECTtGN MAN[F�D � Stormwatex runoff enters the manhole or concrete sttvcture via an inlet pipe and begins to 6ll the structure. An energy dissipator at the vault inlet slows the influent ' water and allows coaise sediments to settle tvithin the structure. ��Ihen the water ' surface elevation in the vault/manhole reaches operating level,water flows thxough the '' BFC driven by a hydrostatic head. Within the BFC, the water flows through a proprietary filter media and drains via a vertical pipe. The vertical drain is connected to the underdrain system which conveys 6ltered water to the outfall. During a rypical storm eeent,the BayFilterT`�system has Four cvcles: 1. Vault fill and aiz release; 2 Uniform bed load hydrodynainic 6ltrarion; 3. Uniform bed load siphon filtraaon;and 3 BAYFILTERT"s SPECIFICATIONS PART 1.00 GENERAL 1.1 DESCRIPTION A. The BayFilterTM system's internal components manufacturer selected by the Contractor and approved by the Engineer, shall furnish all labor, I materials, equipment and incidentats required to manufacture the BayFilter system components(s) specified herein in accordance with the attached drawing(s)and these specifications. B. Concrete structures and any appurtenances that form an integrai part of the BayFilterTM system shall be described in Part 2.00 of these specifications. 1.2 OUALITY CONTROL INSPECTION A. The quality of materials, the process of manufacture, and the finished sections shall be subject to inspection by the Engineer. Such inspection may be made at the place of manufacture, or on the worksite after delivery, or at both places, and shall be subject to rejection at any time if material conditions fail to meet any of the specification requirements. If a BayFilter system component(s) is rejected after delivery to the site, it shall be mazked for identification and removed from the site. Any BayFilter system component{s) which have been damaged beyond repair during delivery will be rejected. 1.3 SUBMITTALS A. Plan, elevation, and profile dimensional drawings shall be submitted to the Engineer for review and approval. The Contractor shall be provided with the approved plan, elevation, and profile dimensional drawings. PART 2.00 PRODUCTS 2.1 INTERNAL COMPONENTS All components including concrete structure(s), PVC manifold piping and filter cartridges, shall be provided by BaySaver Technologies Inc., 1030 Deer Hollow Drive,Mount Airy, MD(800.229.7283). A. PVC Manifold Piping: All internal PVC pipe and fittings shall meet ASTM D1785. Manifold piping shall be provided to the contractor partially pre-cut and pre assembled. BaySaver Technologies,Inc. 1 9/7/12-Yersion 1.0 B. Filter Cartridges: Extemal shell of the filter cartridges shall be substantially conshucted of polyethylene or equivalent material acceptable to the manufacturer. Filtration media shall be arranged in a layered fashion to maximize available filtration area. An orifice plate shall be supplied with each cartridge to restrict the flow rate. a. Maximum flow rate for the BFC cartridge shall be 30 gpm at 0.7 gpm per sq-ft. of filter media. b. Maximum flow rate for the EMC cartridge shall be 45 gpm at 0.5 gpm per sq-ft. of filter media. C. Filter Media: Filter media shall be by BaySaver Technologies Inc. or approved alternate. a. Filter media for the BFC cartridge sball consist of 43 square feet of the following mix: sand media shall have an effective particle size of not more than 0.50 mm; it shall have an angular grain shape, be 99% silica, and not leach nutrients. The media shall also include a blend of Perlite and Activated Alumina. b. Filter media for the EMC cartridge shall consist of 90 square feet of the following mix: a blend of Zeolite, Perlite and Activated Alumina. 22 PERFORMANCE A. The stormwater filter system shall be capable of treating 100% of the required treahnent flow at full sediment load conditions. B. The stormwater filter system's cartridges shall have no moving parts. C. The stormwater treatment unit shall be designed to remove at least 80% of the suspended solids load. Said removal shall be based on full-scale testing using SIL-CO-SIL 106 media gradation with a dso of 23 microns (manufactured by US Silica) or equivalent. Said full scale testing shall have included sediment capture based on actual total mass collected by the stormwater filtration system. D. The stormwater filtration system shall reduce incoming turbidity (measured as NTUs) by 50% or more and shall not have any components that leach nitrates or phosphates. E. The stormwater filtration cartridge shall be equipped with a hydrodynamic backwash mechanism to extend the filter's life and optimize its performance. Inlet flow shall be upflow. F. The stormwater filtration system shall be designed to remove a minimum of 50%of the incoming Total Phosphorus(TP) load. G. The stormwater filtration system's cartridges shall have the following minimum flow and sediment load capacities: BaySaver Technologies,lnc. 2 9/7/12-Versian 1.0 I� Design Flow per Treated Sediment Load cartridge-(gpm) (lbs) Nominat 45 EMC 350 30 BFC 150 23 BFC 200 20 BFC 250 15 BFC 300 2.3 PRECAST CONCRETE VAULT COMPONENTS A. Concrete structures shall be designed for H-20 traffic loading and applicable soil loads or as otherwise determined by a Licensed Professional Engineer. The materials and structural design of the devices shall be per ASTM C857 and ASTM C858. B. The minimum compressive strength of the concrete shall be 4000 psi. C. Cement shall conform to the requirements for Portland cement of Specification C150. D. Aggregates shail conform to Specification C33, except that the requirement for gradation shall not apply. E. Reinforcement shall consist of wire confornung to Specification A82 or Specification A496, of wire fabric confornung to Specification A185 or Specification A497, or of bars of Grade 40 steel conforming to Specification Ab15/A615M. F. The access cover shall be designed for HS20-44 traffic loading and shall provide a minimum 30 inch clear opening. G. All joints shall be waterproof with wrapped gaskets or sealed with a mastic treatment. H. Any grout used within the system shall meet the ASTM C 1107 "Standard Specification for Packaged Dry, Hydraulic-Cement Grout (Non-Shrink)". Grades A, B and C at a pourable and plastic consistency at 70°F. CRD C 621 "Corps of Engineers Specification For Non-Shrink Grout." 2.4 CONTRACTOR PROVIDED COMPONENTS Specifications for all contractor-provided components are minimum requirements. If a higher standard is shown on the plans or described in another section of the ' technical specifications, then the higher standard shall govern , BaySaverTechnologies,I�c. 3 9/7i12-�ersion 1.0 I�il A. Sub-Base: Sub-base shall be six-inch minimum of 3/-inch minus rock, 95% compaction. Compact undisturbed sub-grade materials to 95% of maximum density at +/-2% of optimum moisture content. Unsuitable material below sub-grade shall be replaced to engineer's approval. B. The minimum compressive strength of the concrete for cast in place structures shall be 4Q40 psi. C. Silicone Sealant: Shall be pure RTV silicone conforming to Federal Specification Number TT 5001543A or TT 500230C or Engineer approved. D. Grout: Shall be non-shrink grout meeting the requirements of Corps of Engineers CR.D-0588. Specimens molded,cured and tested in accordance with ASTM C-109 shall have minimum compressive strength of 6,200 psi. Grout shall not exhibit visible bleeding. E. Backfill: Backfill shall be %-inch minus rock at 95%compaction. PART 3.00 EXECUTION 3.1 PRECAST CONCRETE VAULT A. Vault top finish grade shall be even with surrounding finish grade surface unless otherwise noted on plans. B. Contractor shall grout all inlet and oudet pipes flush with vault interior wall. C. Sanded PVC fittings shall be used on all PVC inlet and outlet pipes. 3.2 ANTI-FLOTATION BALLAST(Where Required) A. Ballast shall be to the dimensions specified by the engineer and noted on the data block. Ballast shall run the entire length of the long side of the vault on both sides. Ballast shall nat encase the inlet and/or outlet piping. Provide 12" clearance from outside diameter of pipe. 3.3 CLEAN UP A. Remove all excess materials, rocks, roots, or foreign debris, leaving the site in a clean, complete condition approved by the engineer. All filter components shall be free of any foreign materials including concrete. BaySaver Techriologies, Inc. 4 9/7/12-Version 1.0 3.4 FILTER CARTRIDGES A. Filter cartridges shall not be installed until the project site is clean and stabilized or if the inlet and outlet pipes are temporarily blocked off. The project site includes any surface that contributes stormwater runoff to the BayFilter system. All impermeable surfaces shall be clean and free of dirt and debris. All catch basins, manholes and pipes shall be free of dirt and sediments. 3.5 INSTALLATION NOTES A. Contractor to strictiy follow the approved design and construction specifications. Any substitutions are to be pre-approved by the inspector and design engineer in writing prior to placement of materials. B. The stormwater filtration system(s) may not be activated until all contributing drainage areas to each facility are stabilized. Construction of the facility shall not proceed without prior authorization of the inspector. C. No "rock dust" can be used for sand. D. Contact "Miss Utility" at 1-800-257-7777 at least 48 hours prior to the start of construction. PART 4.00 EXECUTION 4.1 INSTALLATION A. Installation of the BayFilter System(s) shall be performed per manufacturer's Installation Instructions. Such instructions can be obtained by calling BaySaver Technologies, Inc. at 1.800.229.7283 or by login to www.BavSaver.com. I BaySaver Technologies,Inc. 5 9/7/11-Version 1.0 i �V� NlSE146'79 � � � OEP � BiY; Mi L� ECOLOGY December 2012 GENERAL USE LEVEL DESIGNATON FOR BASIC TREATMENT CONDITIONAL USE LEVEL DESIGNATION FOR ENHANCED,AND PHOSPHORUS TREATMENT For BaySaver Technologies, Inc.BayFilterTM Ecologv's Decision: 1. Based on BaySaver Technologies' application subtnissions,Ecology hereby issues a GeneraE Use Level Designation (GULD)for the BayFilterTM. • As a stormwater treahnent device for Basic treatment(TSS) removal. • The Basic Treatment GLTLD is for both the BayFilter Cartridge(BFC) and Enhanced Media Cartridge(EMC)and limited to the following maximum flow rates: a. BFC Cartridge maximum flow rate of 0.7 gpm/sf 0 30 gpm(0.067 cfs) per cartridge(43 sf filter area) 0 26-inches in diameter and approximately 28.75-inches tall. b. EMC Cartridge magimum flow rate of 0.5 gpm/sf __`_ 0 45 gpm(0.1 cfs) per cartridge(30-inch diameter)(�0 sf filter area) 0 75 gpm(0.17 cfs)per cartridge(39-inch diameter) (150 sf filter area) c. Media combinations for the BayFilter cartridges are limited to Silica Sand, Perlite, Zeolite,and Activated Alumina. (All filters are limited to 19-inch vertical component to the spiral filter layers) 2. Based on BaySaver Technologies' application submissions,Ecology hereby issues a conditional use level designation (CULD)for the BayFilterTM cartridges. • As a stormwater treatment device for Enhanced treatment(dissolved Cu and dissolved Zn removal)and Phosphorus treatment. • Sized at a design rates no greater than those listed above(GiTLD (Basic) Flow rates). 3. Ecology approves use of BayFilterTM Cartridges using the Silica Sand,Perlite, Zeolite, and Activated Alumina for treatmeot at the above flow rates per cartridge. Designers shall calculate the water quality design flow rates using the following procedures: • Western Wsshington: For treatment installed upstream of detention or retention, the water qua(ity design flow rate is the peak 15-minute flow rate as calculated using the latest version of the Western Washington Hydrology Model or other Ecology- approved coatinuous runoff model. • Eastern Washington: For treatment 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{SWMIVIER� 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. 4. The CITLDs expire on December 1,2013 unless extended by Ecology, and are subject to the conditions specified below. 5. The GULD has no expiration date,but it may be amended or revoked by Ecotogy, and ' is subject to the conditions specified betow. Ecologv's Condi�ions of Use: BayFilterTM units shall comply with these conditions: 1. Design, assemble,install,operate,and maintain BayFilterTM units in accordance with BaySaver Technologies' applicable manuals and documents and the Ecology Decision. 2. Maintenance: The required maintenance interval for stormwater treatment devices is often dependent upon the degree of pollutant loading fram a particular drainage basin. Therefore,Ecology does not endorse or recommend a"one size fits all" maintenance cycle for a particular modeUsize of manufactured filter treatment device. • Typically,BaySaver designs BayFilter Cartridge systems for a target filter media replacement interval of 12 months. • Testing results provided to Ecolog,y for the Basic GULD approval indicate that the treatment system required maintenance after four months of operation. Ecology used the effluent flow rate decreasing to below the design flow rate as the indicator of the need for maintenance. Ecology determined this from the continuous flow monitoring data. This interval does not necessarily determine the maintenance frequency for all Bay�lter systems. • Owners/o erators must ins ect Ba Filter s stems for a minimum of twelve months II P P Y Y from the start of post-construction operation to determine site-specific maintenance schedules and requirements. Owners/operators must conduct inspections monthly during the wet season,aud every other month duriag the dry season. (According to the S�V1I�IlVIWW,the wet season in western Washington is October 1 to Apri130. According to SWMMEW,the wet season in eastern Washington is October 1 to June 30.)After the first year of operation,owners/operators must conduct inspections based on the fmdings during the first year of inspections. � Conduct inspections by qualified personnel,follow manufacturer's guidelines, and must use methods capable of determining either a decrease in treated effluent flowrate andlor a decrease in pollutant removal ability. 3. When inspections are performed,the following findings typically serve as maintenance triggers: • Accumulated vault sediment depths exceed an average of 2 inches, or � Accumulated sediment depths oo the tops of the cartridges exceed an average of 0.5 inches,or � Standing water remains in t6e vault between rain events. • Bypass during starms smaller than the design storm. • Note: If excessive floatables (trash and debris} are present,perform minor maintenance consisting of gross solids removal,not cartridge replacement 4. The filter fabric used in the BayFilter is highly oleophilic(oil absorptive); therefore, hydrocarbon accumulation on the filter may cause premature failure. Oil control BMP's should be installed upstream of BayFilter installations if warranted, and/or the BaySaver should be inspected after any known oil spill or release. 5. BaySaver Technologies Inc. commits to submitting a QAPP for Ecology approval by June 1,2012 that meets the TAPE requirements for attaining a GITLD for enhanced and phosphorus treatment. The monitoring site(s)c6osen should be reflective of the product's treatment intent. Baysaver shall monitor sites prior to installation of the canister to ensure concentrations of the monitored constituents are within TAPE guidelines. 6. BaySaver Technologies Inc. shall complete all required testing and submit a TER for enhanced and phosphorus treatment for Ecology review by Apri130,2013. 7. BaySaver Tec6nologies Inc. may request Ecology to grant deadline or expiration date eztensions, upon showing cause for such egtensions. S. Discharges from the BayFilterTM units shall not cause or contribute to water quality standards violations in receiving waters. Applicant: BaySaver Tech.nologies Inc. Applicant's Address: 1030 Deer Hollow Drive Mount Airy,MD,21771 Application Documents: • Technical Evalteation Report BayFilter System, Grandview Place Apartments,Vancouver, Washington and Appendices A through O (May I8, 2011) � Washington State Department of Ecology Technolog�Assessment Protocal— Envirorrmental BayFilterTMCondttional Use Desigrration Application(March 2007) � BaySaver Technologies,Inc.BayFilterTM System Washington State Technical and Design Mamral, Version 1.1 (December 2006) • Eff ciency Assessment ojBaySeparator and Bay frlter Systems in the Richard Montgomery High School January 6.2009. • Eval:ration of MASWRC Sample Collection, Sample Analysis, and Data Analysis, December 27,2008 • Letter from Mid-Atlantic Stormwater Research Center to BaySaver Technologies, In. dated October 22,2009. • Letter from Mid-Atlantic Stormwater Research Center to BaySaver Technologies, In. dated November 5,2009. � Maryland Department of the Environment letter to BaySaver Technologies dated Jan. 13, 2008 regarding approval of BayFilter as a standalone BMP for Stormwater treatment. • NJCAT letter to BaySaver Technologies dated June 18, 2009 regarding Interim � Certification. Applicant's Use Level Request: • General use level designation as a basic, enhanced, and phosphorus treatment device in accordance with Ecology's Stormwater Management Manua( for Western Washington. Applicant's Performance Claims: • Removes and retains 80%of TSS based on laboratory testing using Sil-Co-Sil 106 as a laboratory stimulant. • Removes 42%of dissolved Copper and 38%of dissolved Zinc. • Expected to remove 50% of the influent phosphorus load. Ecology's Recommendations: Ecology finds that: • Ecology should provide BaySaver Technologies, Inc. with the opportunity to demonstrate, through additional laboratory and field-testing,whether the BayFilterTM system(as a single treatrnent facility) can attain Ecology's Enhanced Treatment and Phosphorus removal g�als. Findings of Fact: • Based on field testing in Vancouver, WA, at a flow rate less than or equal to 30 gpm per canister, the BayFilterTM system demonstrated a total suspended solids removal efficiency of greater than 80% for influent concentrations between 100 and 200 mg/l and an effluent concentration<20 mg/1 for influent concentration< 100 mg/1. • Based on laboratory testing,at a flowrate of 30 GPM per filter,the BayFilterT"' system demonstrated a total suspended solids removal efficiency of 8I.5°/a using Sil-Co-Sil 106 with an average influent concentration of 268 mg/L and zero initial sediment loading. • Based on laboratory testing, at a flowrate of 30 GPM per filter, the BayFilterTM system demonstrated a dissolved phosphorus removal efficiency of 55%using data from the Richard Montgomery High School field-testing. The average influent concentration was 0.31 mg/L phosphorus and zero initial sediment loading. • Based on data from field-testing at Richard Montgomery High School in Rockville, MD the BayFilter system demonstrated a Cu removal efficiency of 51% and 41% for total and dissolved Cu respectively. Average influent concentrations are 41.6 µg/1 total and 17.5 �g/1 dissolved. • Based on data from field-testing at Richard Montgomery High School in Rockville,MD the BayFilter system demonstrated a Zn removal e�ciency of 45% and 38% for total and dissolved Cu, respectively. Average influent concentrations are 354 µg/1 total and 251 µg/1 dissolved,respectively. Other BayFilterTM Related Issues to be Addressed By the Company: 1. The Washington State field test results submitted in the TER do not yet show whether the BayFilterTM system can reliably attain 30%removal of dissolved Cu, 60%removal of dissolved Zn, or 50% removal of Total Phosphorus found on local highways,parking lots, and other high-use areas at the design operating rate. 2. BaySaver Technologies, Inc. should test a variety of operating rates to establish conservative design flow rates. 3. The system should continue to be monitored to measure bypass and to calculate if the system treats 9I%of the volume of the total annual runoff volume. 4. The system should be tested under normal operating conditions, such that the settling basin is partially filled with pollutants. Results obtained for"clean"systems may not be representative of typical performance. 5. Conduct field-testing at sites that are indicative of the treatment goals. b. BaySaver should continue monitoring the system for a longer period to help establish a maintenance period and to obtain data from additional qualified storms. Conduct testing to obtain information about maintenance requirements in order to come up with a maintenance cycle. 7. Conduct loading tests on the filter to determine maximum treatment life of the system. 8. Conduct testing to determine if oils and grease affect the treatment ability of the fitter. This should include a determination of how oil and grease may affect the ion-exchange capacity of the system if claims are to be made for phosphorus removal. 9. BaySaver should develop easy-to-implement methods of determining when a BayFilter system requires maintenance(cleaning and filter replacement). 10. BaySaver must update their O&M documents to include information and instructions on the "24-hour draw-down" method to determine if cartridges need replacing. Technology Description: Download at www.BaySaver,com Contact Informallon: Applicant: Tom Pank BaySaver Technologies, Inc. 1030 Deer Hollow Drive Mount Airy, MD, 21771 (301) 829-6470 t��ci�baysaver.com Applicant website: www.BavSaver.com Ecology web link: httn:liwww.ecv.wa.Qov/programs/wq,�stormwater/newtech/index.html Ecology: Douglas C. Howie, P.E. Department of Ecology Water Quality Program (360)407-6444 douglas.howie'a,ecv.wa.gov Revision Histor Date Revision A ri12008 Ori inal use-level-desi ation document February 2010 Revision Au st 2011 GULD awarded for Basic Treatment Apri12012 Maintenance r uirements u dated. Au st 2012 Revised desi storm criteria December 2012 Revised contact information and document formattin BAYSAVER TECMNOLOGIES, INC. � Insta�atic�n o� a 11�anhaie Bay�i�� 1. Contact utility locamr to mazk anjT nearb}' underground udlioes and mal:e sure it is safe to excavate. 2. Reference the site plan and stake out the location of the BayFilterTM manhole. 3. Excavate the hole, pro�riding any sheeting and shoring necessari� to comply with all federal,state and local safety regutaaons. 4. Level the subgrade to the proper elevation. Verif�r the ele��ation against the manhole dimensions, the invert ele��ations, and the site plans. Adjust the base aggregate,if necessary. 5. Have the soil bearing capacity��erified bj� a licensed engineer for the xequired load bearing capacity. On solid subgrade, set the base of the BayFilterTM manhole. 6. Check the lei�el and elevadon of the base unit to ensure it is conect before adding any riser sections. 7. Add watertight seal (either masric rope or rubber gasket) to the base unit of the BaS�FilterTM manhole. Set riser section(s}on the base unit 8. Install the PVC watertight oudet manifold �vithin the BayFilterrn1 manhole. 9. Install the inlet pipe to the BayFiiterTM manhole. 10. Install the energy dissipatorJlevel spreader at the system inlet locarion. 11. After the site is scabilized,remove anj�accumulated sediment or debris fcom the manhole and install the BayFilterTM carnidges. 2s B A Y S A V E R T E C N N O L O G 1 E S, 1 N C. Installaticm af Precast Vau�t BayF�terTM 1. Contact utility locator to mark any nearbj• underground utilities and ma1:e sure it is safe to excavate. 2. Reference the site plan and stake out the location of the BayFilterT�`1 vault. 3. Exca��ate the hole, providing any sheeting and shoring necessaz}� to comply with all federal,state and local safety reguladons. 4. Level the subgrade m the proper elevation. Verify the elevadon against the manhole dimensions, the inverc elevations, and the site plans. Adjust the base aggregate,if necessary. 5. Have the soil bearing capadty��erified bp a licensed engineer for the required load bearing capacity. On solid subgrade, set the fust secdon of the BayFilterTM precast vault 6. Check the level and elevation of the first section to ensure it is correct ' before adding any riser secuons. ', 7. If addiaonal section(s) are required, add a watertight seal to the first section of the Ba}'FilterTM vault. Set additional section(s) of the vault, ', adding a watertight seal to each joint. 8. Insta2l the PVC oudet manifold and oudet chamber s}'stem. 9. Install the PVC oudet pipe in BayFilterTM vault. 10. Install the inlet i e to the Ba FilterTM vault. pP Y 11. Install the energS�dissipator/level spreader at the inlet pipe. 12. AEter the site is stabilized,remove an}'accumulated sediment or debris from the vault and inst�ll the BayFilterTM camidges. � � I! BayFilter ' M ai n t en an ce Gu i d e Phone (301)829-6470 Toll Free 800-229-7283 Fax (301} 829-3747 - � _ � �'�� s �...�'� � �� _ _ , 5 ,�� ' �> ' � � ff �� . . r : F� � ` . _.� - � � ��, s _ � � a , ,� K,,; �� f } f Y ��i�,�� i . . x� �� .i. 4��1.,.E = : � � , ��.;:� "''' . '� ` . ' � p .....:.� .. .. ,� `,. i '��1_ 3 . _ �.._:'su _ ss.,� ' _ _.. :�.a � � t� �,.,�� . - _..__ �� F :�� L� Pi. . i � : �� ._:�_�-�. �. . . � �� 3�� e �., . � � ` 6 _ . �,,� � � �� . � �` ��'��, ��q,_�= �. S�oRht WarfR hiaxacE��F��r; �� '� �° �� K r�: � � : � � �� _ _�__.w. _�_� , � �� Y � F,� € , 30J-869-21D0 ' � � � >- . � � . � �i��tth�tcG�tttg. MA � - ' � � �"�'= �� '"i �.� _ �: �` �" - _.�—� - _. -� _ _ � � �� , i � � -�x. _ � - � - ,� �� ; `� � - �� $ y - _n � �..�f�.� -.. �' ' :`' . :�' ��:.�:a_.�.� a = _ _�``''� � - � �`�� _ � - � �=� � � �- � .�- �� - _ �� _ � � >� ��_. �' �. - - . . h..�_ _ ,r = � ; .,_y� � 3:�� :S�I m2009 BaySaver Technologies, Inc. www.BaySavet.com 1302 R3sing Ridge Rd. Unit 1 • Mount Airy, Niaryland 21771 (301) 829-G470 Toll Free 800-229-7283 Fax (301)829-3747 ` � BayFilterTM Maintenance and Operations Overview The BayFilteiTM system tequices periodic 111Sp�lOf1�f11811tEf17102t0 OOf1tiCllJ@OpEf�lll��thBdPS�'1 effidency. WFt�718 BayFllterT"� system is first installed,it is recommended that it be inspected every six {6) months. During the sy5tems first mantenanoe cyd� inspedion is required � edery sx months and �ter m�or storm eventsto determineratesof sediment and pollution aoamufation.When thefilter system achibits flows beJow desic,�n levds, the system shauld be maintaned. The mo�t effiaent wa�r of d�ermining whether thesystem isoper�ing bdow desc,�flow-r�es cai be pe-Formed by visral ins�ections The mantell7toe pfocess comprises the removal and replacement of each BayFilterTM cartridge and the cleaning of the vault or manhole�vith a�racuum truck.BayFilterTM maintenance should be performed by a Bay�er Technoio�es, Inc. oertified mantenaioe oontractor, or other paty traned by Bay93ver Techr�olajes, l nc. Bay3�✓er Technolcx,�es, I nc. offers three different options to owners of a system in regads to mantena-i�outlined bdow. • Bay�ver Technologes offas education aid traning services to owners of, or muniapalities mantaning their BayFilter systems • If the st�owner or muniapality would preFer to outsource manteianoe oper�ions to a third party, Bay�+er Tedinologes mantans a list of oertified oontradors in the geogr�hic region needed. • lf the st�owner or muniapality would prefer that B�yRaver Technolajes, Inc. mantan the sy5tgns, a contract can be reached between Ba�ver and the owner, in which Bay�ver will outsouroetheservicesto aoe�tified mantenanoecontractor. If the s�stem being instailed is a pilot test projed for the Washington St�te Depatrr�ent of Ewlogy, I' Bay�er will maintan thesystem until testing h�completed. Thae as two oore wmponasfs of maintenanoe on a Ba�Filter system. The first component is the required seni-ainual in�ionsof thesystem,theseoond isthemanta�aioein which thefiltersrequire rq�laoen�ent. General I nspection Procedure D uring a storm�ver�t • I n�ions c�n be performed during both dry a1d wet se�on, e�en during a storm-evait. I n Washin�on, the filter systems ae deagned in ai off-line configur�ion. After lifting the acoess wver from the top of the va�lt or ma�hol� w�a will c�ident within the system. If water is spilling over the bypa�swer d�ing a storm,thefilters ae probably operating below desgi-flow rates The only acoe�tion to this is in the ca9e where the spifl-over is observed during a peek storit�rent, in which some of the flow will bypa�s the system. lf flows ae observed spilling over the bypass during a storm ewent, a seoond inspec�ion should be scheduled duing a dry- period to verifythefiltersaeoperatingbelowthedesgi eFfiaency. —� i • I f no water ca�be observed bypa�i ng the system during a storm event,it c�be conduded that � the BayFilt� system is oper�ing as desg�ed. Continue regular inspections at the sx-month interval until an average lif��y+de has been determined for the particula�stem. • I n addition,the BayFilter system still needs to be inspeded a�ter major storm ev�ts !, D uring a dr�� An inspec�ion during a dr�period is prefared over an inspection d�xing a storm Event, because i in addition to indicating to the inspedor whether or not the system is 0cpired, lifecyde estimates ca� be determined by the amount of sediment aocumul�ed at the bottom of the housing structure • During a dry period, the insde of the va�lt or ma�hole should only carry a modest ano�t of �vater (<_1'�. If more rhan one inch of water is obsaved � the floor of the vault, the system needs to be mantaned. � Assuming water le�-els within the housing structure indicate the system isn't espired, sediment �ould be measured to d�ermine the rate of aocumulation. BayFilta systerns �ould be mantaned when four indies of sedimait have aocumutated on the floor of the vaultl manhole to ensure proper opa�ion of thedran-down modules General Mairrtenance Proc�dure Mantenanoeof the BayFilter sys#an requirestheremoval a�d re�lacement of the BayFilter catridges, vaouuming of the bottom of the housng structur�and r�a�rnbly of the drain-down manifold. 1. R�rnov�e the ma�hole oov�s aid open�I acoess hatches 2. BeFore enteri ng the system make sre the ar is saFe per 09-I A Sta�dads or use a bre�hing apparatus. Use low 02, hi�CO,or other applicablewaning devioes per regulatory requiranents 3.Usng avacuum trudc renove any liquid and sadimentsth�can be removed prior to entry. 4. Usng asmall lift or the boom of thevacuum trudc,ranovethe used catridg�s by lifting thefn out. Usethetrolleysystem to removecartridgeswhen applic�le. 5.When all ratridgesae removed, rgnovethebala�oeof thesolidsaxf water;then loosen theunder dran manifold and removethedran pipesaswell. Carefullycapthema�ifdd and rhe Fern�o's and r;,�se thefloor,remo�ingthebalanoeof thecollec�ed s�lids. 6.Cleai themanifold pipes,insped,and reinstall. 7. i nstal I the exchange c�rtridges atid dran-down modules,then dose all oovas i � D. R. STRONG CON5ULTIIVG ENGINEERS May 22, 2013 Project No. 12029 Jan Illian Development Services City of Renton / 1055 S. Grady Way, 6'h FI. � �i'� Renton, WA 98057 �3 G� Re: Project File No. LUA12-076, ECF, PP �� Piper's Bluff � Dear Ms. Iliian: Thank you for your coordination and review of this project. We have carefully considered each of the comments in your letter dated April 3, 2013. Additional information has been provided and revisions have been made, as appropriate. The following is a summary of the actions taken I in response to each comment. ' Storm Drainaqe Comments: 1. See pages 8 and 9 of attached wetland report. 2. See pages 8 and 9 of attached wetland report. 3. See pages 8 and 9 of attached wetland report. � a. Spill control measures will be achieved in the control structure with FROP tee. See � sheet C13. �b. Spill control maintenance and operation manual have been included in Section X of the drainage report. 4. A note has been included on sheet C8 which will allow the City to access the Site for the inspection of flow control BMPs to be constructed on the lots. The note shall also be �� included on the final plat map. (,a�c��'�,.-5. The HOA shall be responsible for the maintenance of landscaping within Tract "A". The City P�`f� � shall be responsible for maintenance of the drainage facilities constructed within Tract "A". A storm drainage easement to benefit City of Renton shall encompass all of Tract "A". � �6. A fence has been placed around the perimeter of the pond. II 7. Outfalls have been sized according to 2009 KCSWDM. See Section V of the Drainage I Repart. , 8. The outlet of the stormwater facility is proposed within the wetland buffer, which is an ', exempt activity per RMC Chapter 4-3-050.C. However, any area disturbed during �, installation of the outfall will be restored with native trees and shrubs. �� 9. Additional notes (a, b and c) have been added to the ESC Plan. � � 10. Within the drainage plan, the additional comments have been noted, two catch basins have been provided on Hoquiam Ave NE, and catch basin 1 has been altered to a dual directional vaned grate. According to Chapter 4.2.1 in KCSWDM 2009 under pipe clearances, a minimum of 3 feet horizontal clearance shall be provided between storm drain pipes and other utilities. This is provided. Sewer Comments: 1C.,_-.N E - ^I�r� Sui'e�.._ 1 a. All DI pipes have been changed to C900. "�rPno eV(25)827-3CS3 1b. Sanitary Sewer Manhole 2 now has a 90 degree connection with Sanitary Sewer Manhol��l�4zs�sv-�a^� Toll Free:(800)962-1a�_ vrnw.drstrong cc�- Engineers � Surveyors I Landscape Architects . Jan Illian Ii hlav 22.2013 I + Page 2 of 2 ', 1 c. A typical side sewer callout is shown on the Sanitary Sewer Plan as weil as all the invert elevations of the stubs. Street Comments: 1a. A transition ramp is shown in the NE corner for pedestrian use. 1 b. See 1 a. � 1 c. Clear space has been limited to one location in the middle of every block for fire trucks and I, minimized to 20 feet with the 5 additional feet included in the planter. 1d. No parking signs have been added within the fire truck clear area space and also on one side of street. 1 e. The paving note has been added to the plan sheet. 1f. The cross section has been adjusted to match what is shown on the plan sheet. Detail Comments: 1. All current storm and sewer details are included on the detail sheet. I' If you have any questions regarding the revisions, please do not hesitate to contact me. Sincerely yours, ;, D. R. STRONG Consulting Engineers Inc. I ; '� , , I Nadeem . Khan Senior Design Engineer NAK/qhh R:',2012'.0�]20?9�3 iDoctmreia�s lLetters'�L 130-116 lllinn.cloc . , __ _ _--- ,--�` ;� Sewall Wetland Consulting, Inc. - -_ 27641 Co��ngtpn 1 ti'ay SE#2 Phone:25_'i-8.59-0615 ----- Covmgton WA 9�2 Fax:25.�852-4732 April 15, 2013 Peter O'Kane � WestPac Homes, LLC 7449 West Mercer Way Mercer Island, Washington 98040 RE: Pipers Bluff Plat—Rei�ised City of Renton Critical Areas Report & Supplemental Stream Study SVVC Job#12-135 1.0 INTRODUCTION � This report describes jurisdictional wetlands and streams on the 5 acre proposed Pipers Bluff Plat, located on the east side of Hoquiam Avenue NE in the City of Renton, Washington (the"site"). Specifically,the site consists of a rectangular shaped group of four(4) abutting parcels in a portion of the NE '/4 of Section 10,Township 23 North, ' Range 5 East of the Willamette Meridian in King County, Washington. -- -- m .��»,�.�, � �m Ne za,d s: r��,y� � , s b m � � � m e a n NE 2ttti P1 TJE MIh SI � NE 2U.7i St D Nf t5th S! SE 1Wtn St W o a z �ia„s� "' � a TD o mz � 2¢• �d° ^ � � -�' � � � Y �!�iiTfn � $�1J7L.,S( � � �1jN m � � m NE 17tA St Se t07tn P�, m Si NE 17ta St D � s o ��gpd ^ tiEt6ln5t e �� Z l� R�on hse > m a Z � > m � Q 0 3 c � o � 9q�,, m �e� �,S�amdB� 3 , 'Q1 k� � n Rm3lCIK.�• NE 12tn 51 `�"`� � hE t2in St � �`'NE 12Sn St ^� SE:17th St $� SE ttrhq � _� SE n3tn St > o < rJE 17tr C' : NE 111�Sf m m 1M h[1�mSt SE1!4m: z z � ot�vER M � NE tcan oi g � = HAZEN HiGH ��pi + —'� SCHOGL � $ M1F�mm� � ' o NE�9[h St NE�Ct`St g SE i ¢` 2 y a .6 � m `e & � � SE 1T7U1 St i'lcir�ity Mnp Aipers Bluff'�12-13_S Sewall i1'etland Consulti��g, Irrc. Apri!I5, 2013 Page 2 The site consists of four Parcels including#1023059002, #9367, #9312 & #9144. Single family homes are present on two of the parcels along Hoquiam Avenue, and the remaining property besides the associated lawns and landscaping is undeveloped forested area. The site is proposed to be subdivided into 30 single-family residential Lots��ith associated roads, and infrastructure. 2.0 METHODOLOGY Ed Se��all of Se��all Wetland Consulting, Inc. inspected the site on June 6, 2012.The site «�as reviewed using methodology described in the Washington State Wetlunds Identifrcation Manual(WADOE,March 1997). This is the methodology currently recognized by the City of Renton and the State of Washington for wetland determinations and delineations. The site��as also inspected using the methodology described in the Corps of E�igineers Wetlujzds Delineution Ma�icral (Environmental Laboratory, 1987), and the Western Mou►�tains, Vulleys und Coast region Supplement(Version 2.0) dated June 24, 2010, as required by the US Army Corps of Engineers. Soil colors�vere identified using the 1990 Edited and Revised Edition of the Mu�tsell Soi/Color Charts (Kollmorgen Instruments Corp. 1990). The T�'ashin ton State Wetlancls Identi rcation ar�d Delineation Mar�ual and the Cof• s o g .f P .� Engineers Wetlands Deli�eatios�Mar�a�al/Regional Si�pplenzent all require the use of the three-parameter approach in identifying and delineating wetlands. A��etland should support a predominance of hydrophyrtic vegetation, have hydric soils and display wetland hydrology. To be considered hydrophy�tic vegetation, over 50%of the dominant species in an area must have an indicator status of facultative (FAC), facultative wetland (FACW), or obligate wetland (OBL), according to the National List of Plant Species That Occur in Wetlands:Northwest (Region 9) (Reed, 1988). A hydric soil is "a soil that is saturated, flooded, or ponded long enough during the growing season to develop anaerobic conditions in the upper part". Anaerobic conditions are indicated in the field by soils��ith lo�v chromas(2 or less), as determined by using the Munsell Soil Color Charts; iron oxide mottles; hydrogen sulfide odor and other indicatars. Generally, ��etland hydrology is defined by inundation or saturation to the surface for a consecutive period of 12.5% or greater of the growing season. Areas that contain indicators of wetland hydrology beriveen 5%-12.�%of the growing season may or may not be wetlands depending up�n other indicators. Field indicators include visual observation of soil inundation, saturation, oxidized rhizospheres, water marks on trees or other fixed objects, drift lines, etc. Under normal circumstances, indicators of all three parameters ��ill be present in «-etland areas. Piper.c t3ltrff��'12-13� Sewall li"etland Consulting, I�7c. April 15, 2013 Pu�e 3 Follo«-ing delineation ofthe wetland and stream on the site,the flags were surveyed by D.R. Strong Consulting Engineers (see attached survey). 3.0 OBSERVATIONS 3.I E_risting Site Documentation Prior to visiting the site a revie�v of several natural resource inventory maps ��as conducted. Resources reviewed included the NRCS Soil Surve��, National \�'etlands Inventory, and the City of Renton's �'�'ater Class map. 3.I.1 Soil Survey According to the Soil Surve}, King County Area, Washin�on (Sntider et al 1973),the entire site is mapped as containing Alderwood gravelly loam soils (Map Units AgC & AgD). Alderwood soils are moderately-well drained soils formed in glacial till under conifers. Alder�vood soils are not listed as a "hydric" soil according to the publication Hvdric Soils of the United States (USDA NTCHS Pub No.1491, 1991). Ho��ever, Alder��ood soils can contain small inclusions of poorly drained hyric soils such Norma. Bellinaham, Seattle, Tuk��-ila and Shalcar soil series. _� _ �- __ � . '` ,__ �_ -- - �,� _ �� .� � .. ..c, , � � � � ;�: �. y z �� 'c�� . �,� � _ � - �. .'s- '� �� :� �� . �� ; � � � '�� .�_. . �_ _ , . , . f .z�: T � �- z=- �' ��_� - _ � _ .' i`-E'". � � � � :�� _ - � x ; ' __:,. ,� . �_. y + . '' �-��? = ' " .. s � ._ —^ • _ � : . _ .:... � _ � � . -... � ...,. �i �; �.� '��,_ ` � �-�� ' _ _ . . . � .. , � ... �- � � � � `� � �k §� �rt> �:£,_ - � � `:��+3111itr� �`- '�r. �-- y-_ _ �r : _ ��_.�� Il ,1�� i Soil_llul��uf�tl�t� .Sitt° Pi ers Blu i�12-135 �� P �� Sex-all 1�'et/and Consulting,Inc. , .4p�•il I5, 2013 Page 4 3.1.2 Nutional Wetlands Inventory According to the National Vl'etlands Im�entor} there are no wetlands or streams located on or near the site. +e�c r�;t� `'�''�` }` � �. ��` � �s �, �" �.s` ,�`� `�� : � : r � � �,� - � �, � �,- �' # � ��4 � � �C � E� �- ':�.¢ 3 s'�t ,,. � �.,. s�, '� i � a '� �f �� e� �f s '' � =� _i � �. * "�`` a :f rii{� ��i'L � � .�t:`:` � y'�.. a. .� .� � �` x��'' �t� '� ��', �..^'��`'�. �` . �s i+ �Rl w' "� .r.�t� � �- � �� 'rv � �t C � �� V�c�ti��n�r1 Ii��tluf�cl.�Ij�i�r�rtc��.l�iil�r�� 3.1.4 Cit,y- of Renton Water Class Map According to the City of Renton Draft Water Class Map, the upper reach of Honey Creek is located on the northeast corner ofthe site. This stream is mapped as a Class 4 stream b}-the City(bro�o�n stream shading). Pi/�cr.e Rltrlj'r:l?-13i Setiral! li'e�lurid Coas�rlti�ig, l��c. Apri! 1�, 2013 Page S 5� _. -� . :.:-..:.. ._;- SF MOm R �rt Mi�" �. e �:zz�. �� x �ura — �e3e—� ��c;r� C r��ta :: i ,�IE 71nd °ME 2a1 R � —_ NE 21a1 � i �� t � rtt R ; nF:r,a . .;� i 1 F �s q b! � i�� :e � _.. �-.AF.i7 .. K f9b � �� G•S 5�,+�'�t.. �I E i k h R �:i �tl� 0 tC 19H �' '��c an,� � � --- ,� � �' v„��mm� r--- �-�: }� –� ' Y nt f7i� �j�'�13., g 1E 1� c` CC'i pC�- '� �__— �: 6� O � �Y 4�� p 7 � � ' ^ �: 4�•+''� � s�,� a j� Y � � a v'� a_,.,�.' � 2mSt � ......� �` , �a .... � .�� .._ AII t',t•�v I � x �ICI �`� . �� .x SE•'3t�. 0 � i i � ._ $1' s `�'�'�''�' i � � NE ' IdA St � i9 �t61M A � A �� . .-=_�. .... bl g tt77,st g tt?!1�. n� __... _��.,,� � ._ . __ bi. 9Mi q. ' ._.�.. ��.. EM Ct £ ; - if` - _Abnt�e: Citv orRentof7's i�'ater Tt�e hfap 3.2 Field Obser��ations 3.21 Upla��ds The site is located near the crest of a hill ��ith the property sloping dow n to the east towards Honey Creek. As previously mentioned, several structures as�vell as associated la�vn, driveway and landscaped area is located along the west side of the site. The area along the west side of the site includes immature red alder, big-leaf maple, old apple trees, cottonwood, dense thickets of blackberry, hazelnut, salmonberry and sword fern. The �vestern end of the site appears to have been cleared at one time but has been re-vegetated ��ithin the last 20+years. The majority of the site is covered��-ith a mixed forest�vith conifers as the main component in the overstory. Douglas fir�vith several 4'- 5' dbh specimens are the dominant species in the overstory with scattered big leaf maple and red alder. Understory species include hazelnut, indian plum. elderberry. s�vord fern. salmonberry, and stinging nettle. Soil pits excavated within the upland area of the site revealed soils«ith proliles similar to the mapped Alder�vood series. i Pipers Blt ff'�12-135 Setivall l�'etlai�d Consarlting, Ii�c. April 1�, 2013 Page 6 3.2.2 Wetlands I A single scrub-shrub, riparian�;retland was identified and delineated along the northeast corner of the site. The�vestern edge of the�vetland��ras flagged with orange/black flagging labeled AA 1-AA2-A 1-A7, and the east side with B 1-B4. This narrow band of ��etland borders Honey Creek��hich passes through its center flo�i-ing in a northerly direction. Vegetation in this�vetland consists of small pacific w�illo�v, salmonberry, lady fern, skunk cabbage and manna grass. Soil pits excavated �vithin the��etland revealed a sapric muck soil with a color of lOYR 2/1 ��-hich��-as saturated��ithin 12"of the surface. �'etland A«�ould be classified as PSS1C (palustrine, scrub-shrub, broad leaved deciduous, seasonally flooded) according to the US Fish and Wildlife Wetland Classification methodology(Cowardin et al. 1979). � According to the criteria in City of Renton Municipal Code (RMC) Chapter 4-3-O�O.M.1, Wetland A��-ould be classified as Category 2 wetland. Category 2 ��-etlands are defined in the Code as follo��s; 11. Cutegorp 2: Category 2 wetlar�ds are ivetlands tivhich meet one of-ntof-e of the folloiving criteria: (aj l�'etlands that are �rot Catego�y 1 or 3 tivetla�rds; and/or (bj j�'etlands thaJ have heron rookeries or osprey nests, but are not Categofy 1 wetlancls; anc�/or• , (c) i�etlands of any si.ze located at the headtia�aters of a lvatercourse, ', i.e., a tivetland u�ith a pes•ennial or seasonal ou�ow channel, but ivith no defined inflatent ' ' char�nel, but are not Category 1 wetlands; a�rd/or , (d) i��etlancls having rsiinir�ium existing evic�enee of hirnxar�-relazed ', physical c�ltef•ation sa�ch as dikis�g, ditchi»g or cl�armelization; arzd�or ' According to Renton Municipal Code (RMC) Chapter 4-3-OSO.M.I,"Wetland A"best meets this rating as a��etland with minimum evidence of human related physical alteration, but not meeting the criteria of a Category 1 or Category 3 wetland. Typically, Category 2��etlands have a 50' buffer measured from the wetland edge. 3.2.3 Streums As previously mentioned, Honey Creek passes through Wetland A and the northeast corner of the site. As required by Code, the ordinary high water mark(OHWM) of the ' creek as I7agged with �vhite/blue dot flagging labeled Wl-W8 on the ��est side and E1-E4 Pipers Bliiff��12-135 Seivall I�'etland Consultir�g, Irac. April I5, 2013 Page ' on the east side. This is depicted on the attached D.R. Strong Consulting Engineers Plat map. Honey Creek is a slo�v flo�i�ing mud and sand bottom stream as it flows northerly through the site. Trash, pallets and tires line the edge� of the creek in this area, although � other��•ise, the stream appears relatively healthy with about 6" of flo«�ing water across its � channel. The stream is strongly influenced by storm�vater outfalls upstream as flow in I the channel �i-as noted to quickly increase follo«�ing a rain event. I, The stream buffer on the project site is very healthy and includes large deciduous and ��i coniferous tree species��-ith a dense native understory. To the east and off-site,this ' buffer has been impacted by clearing and use of the areas as la��n for single family homes to the east. Honey Creek is mapped as a Class 4 stream by the City of Renton. Class 4 streams are "non-salmonid bearing«�aters during years of normal rainfall and/or mapped on Figure 4, Renton Water Class Map, as Class 4". According to RMC Title IV Chapter 4.03.OSO.L.S.a, Class 4 streams have a 3�' buffer I, measured from the OHWT�I of the creek. ' Although Honey Creek is a non-fish bearing�vater in this reach, appro�imately'/4 mile do��rnstream of the site this creek does become fish bearing. As a result this portion of the creek (and associated��etland)has an important function in providing a hydrologic source and attenuating lo�� flo��periods of year for the do��nstream fish bearing section. Wildlife use of the creek is limited to ti�pical urban tolerant«rildlife including deer, raccoon, coyote, 4.0 FUNCTIONS AND VALUES The ��etland on-site was analyzed for function using the Washington State Department of Ecology Wetlands rating System for�h'estern Vl'ashington. This system is typically utilized to classify wetlands, but the classification is function-based, scoring three main functions, 1,)water quality,2) hydrologic function, and 3)habitat functions. Li'etlar7d A-Vl�etland A was rated as a riparian wetland and scored a total of 52 points indicating a Category 2 wetland under this system which indicates inoderate-high overall �� functional value. Its highest scoring function�tiras for water quality«-hich scared 20 points, and its hydrologic fimction�vas moderate at 18 points. Habitat value«ras generally low at 15 points due to the lack of unique habitat features, lack of a variety of plant communities, and the close proaimit}� of de�velopment to its boundaries. �� _ � Prpers Bl�r f'�12-13J Seia�nll {i�'etlai�d Cons��rlting,Inc. April 1�, 2013 Page 8 5.0 REGULATIONS I In addition to the�vetland regulations previously described for��etlands and streams, certain activities(filling and dredging)��ithin "waters ofthe United States" may fall under the jurisdiction of the US Army Corps of Engineers (ACOE). The ACOE regulates all discharges into "��aters ofthe United States" (wetlands) under Section 404(b) ofthe Clean VVater Act. Due to the increasing emphasis on Endanaered Species Act compliance for all fills of �'�'aters of the United State and V6'aters of the State, both the Corps of Engineers and W'ashington Department of Ecology should be contacted regarding permit conditions, compliance, and processing prior to commitment to any fill of�vetlands or streams for this project. 6.0 PROPOSED PROJECT The proposed project is the construction of a 28 lot subdivision with associated access road, and storm water facility. The outlet of the stormwater facility will also pass through the��etland buffer. This is an exempt activity«-ithin the wetland buffer according to RMC Chapter 4-3-OSO.C. Ho��rever, any area disturbed during installation of the outfall«-i11 be restored with native trees and shrubs. 7.0 HYDROLOGIC ASSESSMENT The proposed project has been designed to avoid the wetland, stream and its associated buffer. However, the proposed storm��-ater outfall�vill disperse��ater from the site to the buffer area and the associated wetland and stream. Wetland A is a narro�i�band of riparian��retland«�hich is strongly influenced by Honey Creek flo��•s as well as outflo«�s of storm�vater facilities located south of the site. The creek and water entering the site ' from the south are the main sources of hydrology to the��-etland. Other hydrologic inputs to the creek include direct precipitation as��ell as potentially some minor surficial ground«later outflo��from the site. The amount of«�ater flo�ving from the sites surface to the��-etland and creek appears minimal, with no evidence of sheet flow and only a potential minor contribution from infiltrating precipitation. The project proposes to discharge��ater from the stormwater facilit}'to the edge of the wetland in a rock lined dispersal pad. This should insure water that currentiv makes it��av from the site to the�vetland and creek continues to do so. ; Pipers Bluff�'�12-135 �� Setivall l{�etland Co�zsulting,Inc. , �pril 1 S, 2013 Page 9 Based upon the calculations in the Revised DR Strong Drainage Report for Pipers Bluff (dated January 31, 2013-see table belo«�),there is a minor increase in the flowJ rates off the site from pre-developed rates. This should insure the project will not dry out the �vetland, and that adequate hydrology enters the��etland to maintain its viability. DESIGN INFORMATION INDIVIDUAL BASIN Water Qualit desi n flow Water Qualit treated volume Draina e basin(s Onsite area inlcudes fronta e 4.98 Offsite area 0 T ot Stora e Faali Pond Live Stora e Volume re uired) 69,132 � Predev Runoff Rate 2- ear 0.139 10- ear 0.241 100- ear 0.402 Develo ed Runoff Rate 2- ear 0.928 10- ear 1.12 100- ear 1.88 T pe of Restrictor Fro -Tee Size of orifice(restriction No. 1 0.88 No.2 1.50 � No.3 1.40 Above: Table f3�om DR Str•ong Drainage Report If you have any questions regarding this report, please call us at (253) 8�9-051� or at ese��rall@se��all��c.com . Sincerelv. Se��all I�Y'etlarrd Cof��sultirr�, Is�ac. .......r��-'-��,.�,--' Ed Se�vall Senior Wetlands Ecologist PVl'S #?12 Attached: Data Sheets IVADDE Rc�ting Forrn Site Plan/survey Pipers Bluff/#12-135 Se�vall Wetland Consulting, Inc. April 15,2013 Page ]0 REFERENCES Co�;�ardin, L., V. Carter, F. Golet, and E. LaRoe. 1979. Classification of Wetlands and Deep«rater Habitats ofthe United States. U.S. Fish and Wildlife Service, FWS/OBS-79-31, �'ashington, D. C. Daubenmire, R. 1959. A canopy-coverage method of vegetational analysis. Northwest Science 33:43-64. Diers, R. and J.L. Anderson. 1984. Development of Soil Mottling. Soil Survey Horizons, Winter 1984, pg 9-15. Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual, Technical Report Y-87-1. U. S. Army Corps of Engineers Watervvays Elperiment Station, Vicksburg, Mississippi. City of Renton Municipal Code Hitchcock, C. and A. Cronquist. 1976. Flora of the Pacific North��est. University of Washington Press, Seattle, Washington. Munsell Color. 1988. Munsell Soil Color Charts. Kollmorgen Instruments Corp., Baltimore, Mary(and. , National Technical Committee for Hydric Soils. 1991. Hydric Soils of the United States. USDA Misc. Publ. No. 1491. Reed, P., Jr. 1988. National List of Plant Species that Occur in Wetlands: Northwest (Region 9). 1988. U. S. Fish and Vl'ildlife Service, Inland Fresh��-ater Ecology Section, St. � Petersburg, Florida. Reed, P.B. Jr. 1993. 1993 Supplement to the list of plant species that occur in �vetlands: North��lest(Region 9). USFWS supplement to Biol. Rpt. 88(26.9) May 1988. WETLAND DETERMiNATION DATA FORM—Western Mountains,Yalteys,and Coast Region Praject/Site ��7.�.J ��``� CitylCounty: ��"`"��"`� Sampling Date: G�� Z Appkcant/Owner: State: Sampiing Point: �� fnvestigator{s): �� SecGon,Towtrship,Ranae. �andform(hu+sbpe.terrace,etc.): LQcai reiief(concave,convex,none): S�ope(°�): Subregion{LRR): Lat: Long: Datum: Soil Map Unit Name: NWI cEassificaiion: Are dimaGc 1 hydrobgic conditions an the site typicai for thfs time of year? Yes No_f� (If no,explain in Remarks.) Are Vegetation .Soil ,or Hydrology significantly disturbed? Are'Normal Circumstances'present? Yes � No I Are Vegelation ,Soil ,or HydrWogy naturally problematic9 (if needed,explain any answers in Remarks.y � SUMMARY OF FINDiNGS— Attach site map showing sampiing point locations,transects,impartant features,etc. Hydrophytic VegeW6on Present? Yes Mo � la the Sampled Area Hydric So+l Present? Yes No '� ,� wilhinaWatland7 Yes No Wetland Hydrofogy Present? Yes No Remadcs: �gb�w- /3��yt. �a�..�•°•/1 VEGETATION—Use scientific names ot plants. Absnlute Dominamt Indicator Dnminartce Test worksheet: Tree Stratum (Plof size: ) °�Cover Soecies? Status �mber of Dominant Species t. I�S�� n.�G+i'�J�Q•� G G ��✓ That Rre OBL,FACW,w FAC: � (A) 2. Total Number of DominaM 3 Species Across All SbaW: � (B) 4. Percent ai Domina�t Sgecies =Totai Cover That Are OBL,FACW,or FAC: �� (NBj Sao�innlShrub Stretum (PEot size� 1 t. l��%S ��S�c��— � F�v prevalence index wo►ksheer Z. /Z;.5�s ��,�� .� 3 v Fif-C Total 95 Cover of Muitiolv bv. 3. OBl species x t= 4. FACW speties x 2= 5, FAC species x 3= =Total Cover FACU species x d= H�b Stratum (Plot size: 1 UPL species x 5= 1. }i'lv, ti1'c w,.n. r,�—��--'� _� _L_ Coiumn Totals: (A) fg) 2. g Prevalence Index =B/A= q. Hydrophytic Vegetataon indicators: 5. Dominance Test is>50°h g_ Prevalence�ndex is s3.0' �_ Morptroiogical Adaptations'(Provide supporting 8 data in Remarks or on a separate sheet} 9 _ WeUand Non-Vasc�ar Plants' �� _ Problematic Hydrophytic Vegetation'(Explain) �� `Indicalors of hydric soit and wetland hydrofogy must be present,unless distwbed or probiematic. =Total Cover Woodv Vine Stra3um (Plot size > 1 Hydrophytic z vegetatiw, ✓. Present? Yes No =To:al Cover °/a Bare Ground in tierb Stratum Remarks: US Army Corps of Engineers Westem M ountains,Va'Ieys,and Coasl-Interim Version SOIL Sampling Pant: ��z Profife Description: {Describe to the depth needed to dceument the indicator or confirm the absence of indicators.) Depth btahix Redox Features � I (inches} Color(moistl % Cobr(mast) 96 Type Loc Texture Remarks 3 "' d�� io`in 3/3 _ � ,S L- II 'T G-Concentration,D=De tion,RM=Reduced Matrix,CS=Covered w Coated Sarxl Grains. 'Location: PL=Pore linin ,M=Matrix. Hydrfc Sofi lndicators: (Applicahle to ali LRRs,unless otF�erwise noted.� Indicators for Problematic Hydric Soils': Histosol(At) _ Sandy Redox(SS) _ 2 cm Muck(A10) His6c Epipedon(A2) _ Stnpped Matrix{S6) _ Red PareM Material(fF2} B�adc Histic(A3) _ Loamy Mudry Minera!(F1)(ezcept MLRA 7) _ Other(Explain in Remairks) � Hydrogen SulCde(A4) � Loamy Gleyed Matrix(F2} Depieted Beiow Dark Surface(A11} _ Oepleted Matrix{F3) Thick Dark Surface(At2} _ Redox Dark Surface(F6) 'indicators ot hydrophytic vegebfion and Sandy Mucky I�Aineral(S1) _ Depkted Dar1c Surface(F7) wetland hydrology must be present. Sandy Gleyed Matrix(S4) Redox Depressions(F8) uniess disturhed or problemattc. Restricdve Layer(if preaenq: Type� DepUt(inches): fiydric Soil PresentT Yes No � Remarks: Nu ,.,./, ��1`.i HYDROLOGY Wetiand Hydro{ogy Indicatota: Primarv Indicators(minimum of one required check aU that aooWS Seco�darv Indicators(2 or more reauiredS S�+iace Water(At) _ Water-Stained leaves(B9)(except MLRA _ Waier-Stained Leaves(B9)(MLRA!,2, HigA Water Table(A2) 1,2.4A,and 48} 4A,and 48) Saturation(A3) _ Salt Crust(B11) _ Drainage Pariems(B10) Water Marks(61) _ Aquatic Invertebrates(B13} _ Dry-Season Water Table(C2} Sediment Deposits(B2) _ Hydrogen Suffi�Odor(C1) _ Saturation VisiWe on Aerial Imagery(C9) DriB Deposits(63) _ Oxidized Rhizospheres alorg Living Roots(C3) _ Geomorphic Position(D2) Algal Mat or Crust(B4) _ Presence of Reduced Fron(C4) _ ShaHow Aquitard(03} � Iron Deposits(BS) _ Recent Iron Reduction in Tilled Soils(C6) _ FAC-Neutral Test(D5) SuAace Soil Cradcs(B6) _ Stunied or Stressed Plants(D1)(LRR A) _ Raised Mt Mounds(D6;(LRR A) Inundation Visible on Aerial Imagery(87) _ Other(Explain in Remarks) _ Frost-Heave Hummocks{07) _ Sparsely Vegetated Coneave Surface(B8) �ie Observations: ,//� Surface Water Present? Yes No " Deplh(mches)� Water Table Present? Yes No��pth(inches): Saiuration Present? Yes_ No_ Depth(inches): Wetland Hydrology PreseM? Yes No� (indudes ca ifla ftin e) Describe Recorded Data(stream gauge,monitonng well.aenal photos,previous inspections},ff available: Remarks / / ,/t�o ir d'+ C a /v f US Army Ccrps of Engmeers Westem Ma�ntains Valleys and Coast-Interim Vers�on WETLAND QETERMINATION DATA FORM-Western Mountains,Valleys,and Coast Region Project/Site �"?�^� Ciry�County� � �"� Sampling Date: �' y � ��- AppliqnUOwner. State: Sampling Pant bQ Z �� Investigator(s): �� '�/ Section,Townshg�,Range: Landform(hilislope,terrace,etc.): Local relief(concave,cornex,rane): Slope(°.6►: Subregion{LRR): Lat: Long: Datum Soil Map Unit Name: NWI dassfication Are ciimatic!hydrdogic conditions on Ne site typical for this tirne of year? Yes No � {If no,explain in Remarks.) Are Vegetatior: .SaI or Hydrobgy significantly disturbed? Are'Normal C�wmstances'present? Yes � No Are Vegetation ,Soif or Hydr�ogy naturally problematic? (tf rreeded,explain any answers in Remarks.) SUMMARY OF FINDINGS- Attach site map showing sampling point locations,transects,important features,etc. HydrophyGc Vegetation Present? Yes �No la U»Sampled Area Hydric Soil Present? Yes� No W�thin a Wetland7 Yes �No Wetland Hydrology Present? Yes No Remarks: �,�ovc. Nr r h ti � � � r.,,,, � VEGETATION-Use scientific names of plants. Absolufe Dominant Indicator pominance Test worksheet: Tree Stratum {Plot size: ) 96 Cover Soecies? Status Number of Domfnant Species � t. That Are OBI,FACW,or FAC: (A) 2' Total Number o1 Oominant 3 Species Across AII Strata: �' (B) 4. i =Total Cover Peroent of Dominsrtt Species / U J SadmylShrub Stratum (Plot size_� That Are OBL,FACW,or FAC: (A!B) t. /��"� Sta� •?.S � �'4� Prev�encel�dexworksheet 2. Total%Cower of MulUolv bv: 3. OBL spedes x t= 4. FACW species x 2= 5. FAC spec.ies x 3= =Total Cover FACU spec�es x 4= ' Herb S[ratum (Pbt size: 1 I / ��„` �'' UPL species x 5= t —��" F •y � F�� Colum�7otals: �A1 (B) 2. 3_ Prevalencelndex =BtA= � q, Hydrophytic Vegetation Indicators: ' 3. Dominance Test is>5096 � g, Prevalence Index is 53.0' �. Morphological Adaplations'(Pro�ide supporting � 8. data in Remarks or on a separete sheet} 9 _ Wetland Non-Vascular Ptants' ' Prob►emaGc Hydrophyuc Vegetation`(Explain) ' 70. — ' 'Indicators of hydnc soil and weUand hydro4ogy must I �� be present.untess�sturbed or problematic- i =Total Cover i Woodv Vine Stratum (Plot size ) ' i 1. Hydrophytie � 2 vegetation PresentT Yes No I =Total Cover %Bare Ground in lierb S[ratum Remarks: US Army Corps of Er.gineers Western Mountains.Valleys.and Coast-lnterim Version SOIL Sampling Pant:_�Z �� Profile Description: (Describe to the depth needed to doeument ths indicator or confirm the absence of indicators.► Depth Mahix Redox FeaNres finchesl , Cdor(moistS 96 Cobr fmasU % Tvoe� Loc� 7exture Remarks __� �Q�� Z�f {.�,�,L�,..��l 1G foyh z!/ � 'T : C=Concenhation,D=De tion,RM=Reduced Matrix,CS=Covered m Coated Sancf Grains. 'Location: PL=Pore Lini ,M=Mavix. Hydric Soil Indicators: (Appiicable to atl LRRs,uniess otherwise noted.} Indicators tor ProblemaGc Hydric Soils: _ yistosol(At) _ Sandy Redox(S5) _ 2 cm Muck(A70) '�Histic Epipedo�(A2) _ Stripped Matrix{S6) _ Red Parenl Maieriai(fF2) Black Nistic(A3j _ Loamy Mucky Mineral(F1)(ezcept MLRA 1) _ Other{Explain in Remarks) _ Hydrogen Sutfide(A4) ,_,_ loemy Gleyed Matrix(F2) _ Depleted Below Dark SuAace(A11) _ Depleted Matrix(F3) _ Thick Dark Surface(Al2) _ Redox Dark Sur(ace(F6) 'Indicators ot hydrophytic vegelation and _ Sandy Mucky Mineral(St) _ Depleted Dark SuAace(F7) weqar�hydrWogy must be preseM, S�dy Gleyed MaVix(S4) Redox Depressions(F8) untess disturbed or�oblematic. Restrictive Layer(et preseM): Type� Depth(inches): HydNc Soll Present? Yes � No Remarks: HYDF20LOCsY WeUand Hydrology indkatora: Prima_ry Indicatms(minimum of one rea�red:check aIl that aoolvl Secondarv Ind�cators(2 or rrare reauired) _ Surface Water(A1) _ Water-Stained leaves(69j(except MLRA _ Water-Stained leaves{89)(MLRA 1,2, �Hi h 1Nater Table(A2) 1,2,4A,and 4B) 4A,and 48) uration(A3) _ Saft C�ust{Bt1) _ ihainage Patlems(610) ��Water Marks(B1) _ Aquatic Invertebrates(B13) _ Ory-Season Water Table{C2) _ Sediment Deposifs(B2) _ Hyd�oge�Sulfide Odor(C1) _ Saturation Vsible on Aerial Imagery(C9) _ DriR Deposits�83) _ Oxidized Rhizospheres along LH'rng Roots(C3) _ Geomorphic Position(D2) _ Algal Mat or Crust(84) _ Presence of Reduced Iron(C4} _ Sha�ow Aquitard(D3) _ Iron Deposits(B5) _ Recent fron Redudan in Tilled Soils{C6) _ FAC-Neutral Test(DS) _ Surface Soil Cracks(�) _ Stunted or Stressed Plants(01)(LRR A) _ Ra�sed Ant Mounds{D6}(LRR A) _ Inundation Visible on Aerial Imagery(B7) _ Other(Explain in Remarks} _ Frosi-Heave Hummocks(D7) _ Sparsey Vegetated Coneave Surface(B8) Field Observatioru: Suhace Water Present? Yes No � Oepth(inches):�� ; Water Table Present? Yes ✓No �epth(inches): b � �i Saiuration Present? Yes��No_ Depth(inches): � Wetland Hydrology Present? Yes No , {includes ca iRa lrin e) Describe Recorded Data(stream gauge,mooitonng well,aerial photos,previous inspections),if available: Remarks� US Army Corps of Eng nee�s 11lestem�.lourtains Valleys.and Coast-Interim Vers�on µ'clland n�mc orr,urt�ba Wctland nime m number wETLAND RATING FORM-WESTERN WASHINGTON Docs the wetlnnd unit beinR rnted meet nny of the criteria below? Vcnion 2•Updatcd July 2006 tu in 7c�u eccuracy and rcproducibility among uaen lf you enswer Y�:S to any of ihe questions below you will need to protect thc wctland Updated Ocl 200A with thc new WDFW defutitiom for priority habiWU aeeording to the regulations rogarding the speeial ehnracteristics(nund in the wetland. Nnme ofwetland(if Anou�n): WL , gl,1j -l�.xw DAt�or:ito�i9ir. G-01- Z � �A Check List for Wetlands That May Need Additional Protection YES NO Raccd by_ � 3�,..V� Treined by Ecology7 Yes_No Dace of training in addition to the rotecti0n recommended for its cate o � _._.._._.--- -- _ SPI.Has rhe wetlnnd unit been docr�mented as n hnbitat for am�1�'edernllv lis�ed SGC:__._TW NSI If':__I2NQ&:___ Is S/T/R in Appendix D7 Yes_ No_ T/�reneened rn Endangered anima[nr plant eprNes(l/E species)? For thc purposes of this reting system,"documentcd"mcans the wetland is on the Map of wettand unit:Figure_ Estlmated size a ro rinto state or federal database. SI'2.Ha.s the wt!lnnd unit been documenred as habitnl jor any Slate listed SUMMARY ON itA'CING 77mentened or Endattgered animal species? For thc puryoses oCthis rating system,"documented"means the wetlend is on the eppropriate stare detabese. Note: Wotlands with State listed plant species are Cnte�nry based o UNCfIONS provided by wctland cate orized ns Cate or I Naturnl I lerita e Wetlands sec .19 of data form. 1_ IT_ ul_ Iv_ SP3. Does lhe welland unit confalri individuals ofPrirniry species listed!ry(he WDFYP.Jbr tl�e.stafr? Score for Water Quelity Punetions ZU SP4. Dceslhe wetland imit hm�e a local significrmc¢in addrNon to ils fimctionr7 Category I-Score>-70 For exam Iq the wetland has becn identificd in the Shoreline Master Cntegory II-Swre 51-69 Score for Hydrologic Functions D Category N=Score 30-50 Scoro for Hnbitet Functions Program,the Criticnl Araes Ordinence,or in a local management plan as having special significancc. CateHorv IV�Scorc<30 TO'I'AL score for FuncHons Category bxsed on SPECiAL CHARACTERISTICS of wetland I_ II_ Does not Apply,_ To complele the next nar!oflhe data sheet vor�wl/I need to delerminc the Hvdrogeomorahic Class otthe we�lcmd be�nQ raled. F(rt8I CAtCgOI'y'(chooee the"highest"cntegory from abovej L ]� ' The hydrogeomocphic classificetion groups wellands into those thet funetion in similar wnys. This � simplifies the questions needed to nnswer how well the wetland functions. The Hydrogeomorphic Class ofa wetland can be determincd using Ihe kcy below. Ste p.24 for more detfliled instructions Summa of basic informeHon about thc wetlnnd unit on classifying wetlxnds. Wetland Unit hrs Specinl Wetlend HGM Clsa� : CharacterGttca useU for Ratln , Estuarine De ressional Natural Heritn c Wctlnnd Riverine Bo Lake-frtn e Maturc Forest Slo Old Growth Forest Flats Caastsl La oon Fl�eshwater Ttdal Inferciuoxl None of thc ebove Check if unit hes multiple HGM classes resent WeOand Rntine Fnrtn-weetern Nashington 1 Angu�t 2Q)�1 Wctland Knting Form-wcetcrn�1'achingmn _ Aupust 2(x1J veninn 2�Lo tx:cec<I with Fcningy Nihlica�ion 04.Ofi.0� ver�ion 2 Updamd uitl�ncw NpE'q'dcfini�innv(icc 200R Wetland namc nr nnmber _, Wcqand name ar numbtt_ Clnssi�cation of Wetland Units in Western Washington S.Does the entire wetland unit mect ell of the follawing cri teria7 �e unit is in n vnlley,or strenm chnnnel,�vhere it gets inundnted by ovcrbank If the hydrnlogic crl4erla►bted in eech questlon da not spply to'the enNre anit lieing flooding from that stream or river �7he overbank llooding occurs al lesst oncc every two years. rated,you probably have s untt wlth mulHple HGM claeses. In thi�case,iilenHty whlcL NOTE:The riverine unit cnn contnin depressions that are frlled with wnter yv{ee�i the river is hydrologic crlterla in quesNons 1•7 epply;fndgo to�uestlon 8. "--^� notflooding. , .,-- _� . ,. ..,_,._. NO•go to 6 1,'ES -The wetland dass is Riverine 'ti......._..�.........Q. 1.Are th� . cvcts in the cntirc unit usually controlled by tides(i.c.cxcept during tloods)7 6.Is the entire wetland unit in e topographic depression in which�vater ponds,or is saturated ro the 'SG'O– o YES–lhe wetland dass is Tidel Fringe surfAce,at some time during the year. Thr.r means lhat any outlet,ijpresent,is highPr than the ICyes,is the salinity of the water during penods of annual low flow below 0.5 ppt(parts per rnrerror ofthe wetlond thousand)? YE5–Freshwater Tidel Frinqe NO–Selhvater Tidel Fringe(F.stuerine) NO–go to 7 YES–Thc wetland clnss is Depressionel /jyour wetlm�d can he classified as a I�reshwater Tidnl F'ringc nse[he fornes far Rivnine Z Is the ontire�vetlnnd unit locuted in a very flat area with no obvious depression and no overbank wetlands. Ifit is Salhvater%'idalFsinge it is rated ns an Esluarine wrtluncl Wetlands that flooding. The unit does not pond suttace water more thun a few inches,The unit seems to be were callcd cstuarinc in the frst and second editions ofthe rating system are cnlled Selt maintained by high groundwater in the nrea. The wetiand mey hc ditchcd,but hns no obvious Water Tidal Fringc in the Hydragcomorphic Clessification. Estuarine wetlands werc natural outlet. catcgorized separately in the earlier cditions,and this separation ia being kept in this NO–go to 8 YES–The wetland class is Aepresslonxl revision. To maintain cunsistoncy between editions,the[crm"Estuerine"wctland is kept. Please note,however,ihnt the charncteristics thet define Cetegory I and II estuarine 8.Your wetland unit seems to be difIicult to classify and probably contains several diifbrent HGM wetlands have changed(see p. ). clasee. For examplq seeps at the base of a slopc may grade into a rivorine floodplain,or a smell stream within a depressionel wctlnnd has a zone of flooding along its sides.GO BACK ANb 2.The entire wetland unit is flat and precipitation is the only source(>90%)of water to it. ID�NTIFY WHICH OF THE HYDROLOGIC RE(3IMES DESCRIBED IN QUESTIONS 1-7 �G-�,ro�u-n--d-w�-a�te�r,nnd surface water runotF are NOT sourcea of water to thc uniL APPLY TO DIFFERENT AREAS IN THF.iJNIT(makc a rough skctch to hclp you dccide). Usc �:__n;yu,r' YES–The wetland cfass is Flnts the following tnble to identily the�pproprintc ctass to usc for the rnting system if you hnve scvcrrl If your wctland can be classified as a'Tlats"wetlend,use the form for Depressional HGM classes present within your wetland. NOTE:Usc this table only if the class that is wettands. recommended in the second column rnpresents 10°/or more ofthe total area ofthe we0and unit bcing ratcd. If thc arca of thc cless listcd in column 2 is Icas than 10%of thc unit;classify thc 3. Does the entire wetland unit meet bath of tho following criteria? wctland uaing the clase that roprosents more than 9U%of the tota!area. _'Ihe vegetated paR of the wetlnnd is on the shores af a body of pertnenrnt open wnter (without any vcgetation on the surface)at Ica�t 20 ecres(8 ha)in sizc; HGMClnsses within thr,werlmrd��ni!bein rnted HGMCIass m Use inRntm t Ieast 30%of the ope�water area is deeper then 6.6 ft(2 m)7 Slo e+��verino Riverine ""`�O go YES–T'he wetland class is Lake-trinqe(Lecustrine Fringe) Slo e+De ressional Dc ressional 4.Docs the tntire wetland unit mcet s11 of the following critoria? Slo e+�ke-£rin e Luke-frin e _ Thc weUxnd is on a slope(slope can be very grad�mn, De ressional+Kiverine along slrram within boundnry De ressionnl _The water flows through the wetland in one direction(unidircctional)and usually De roasional �Lakc-Gin c Dc ressional comes from seeps. It may flow subsurface,es sheetflow,or in n s�vale without Salt Water Tidal Fringe and any other class of freshweter Treat as ES'CUARINli under diatinct banks. wetland wctlnnds with specinl The water]eaves the wetland without being impounded7 charectoristics NOT'E: Surjace waler does not pond in lhese lype ojwetlandt except occasionafly in verv smrsll andshal(aw depressians ar b¢hind hummocks(depressions are usunlly If you are uneblc still to determine which of the nbove criterin apply to your weflsnd,or if you diameter nnd Ie.rs thnn 1 joot daep). have more than 2 HGM classcs within a wctland boundary,classify the wetland es Depreseionnl �NO-go to 5 YES–The wetland class is Slope for the rating. Wetlend Reting Fortn--weetem Waelungton 3 Augnst 2004 Welland Rsting Form-wcetcm Washington 4 Auqust 2004 vtteiort 2 UpAaled wi�h new WpF W definitiomi pet 200R venion 2 Updated witli new WDFW definitiona Ocl 2008 Wetland namc or number WctlenJ namc or numbcr R Riverine and Fresh�vater Tidal FriaQe Wetlands Points wAI'ER QuALTTY FiINCT7oNs - Inaicatore thet w�tland fdnetiona to improve «i�� R' ltiverine and Freshwatcr Tidul Fringe Wetlands Points water uali P`6oi� HYDROLOOIC FtJNCTTONS - Indicatore that wotland fUnetione to reduce �� ]t R 1.Does the wetiend unit hnve the t t 1 to Impmve water quafity? (see p.52) tloodie and stream'crbsion' R 3.Doea the wetland unit 6ave t6e te tia to reduce t]ooding and erosion? (see p.54) R l.l Aran of surface depressions within the rivcrine wetland that can trap sediments Flqure_ R R R J.1(.'haracteristics of the overbank storaga the unit provides: figure_ during n flooding event: Esttmate Ihe m+erage wtdth nfthe wetland unit perpendicular la the dtrection nfthe Depressions cover`3/4 area of�+efl¢nd points=8 flrnv und the wtdt{�ofthe atream or river channe!(distance fxtween banks). Calaelate llepfessi0ns Covef?1/2&tea of wetland points=4 �he rutio:(averug¢width oJuniQ/(avrruge widrh ojstream brtween band•sJ. Ii depressions>'/a of area af untt draiw polygom on aarial photo or map.,, Depressions prescnt but cover<1/2 aree of'wetlend +,rpo�nt�'_� ]f the ratio is more tlien 20 points�9 No de ressions rosen[ oints-0 �' If the ratio is betwten 10-20 points a 6 R 1.2 Cheracteristics of the vegetatiun in[he unit(ereaz with>90%covm et parwn height): � Flqure_ If the ratio is S-<10 . R � If the rafio is 1•�5 in =� Troes or shrubs?7/a the aroe of the unit Trces or shrube>V3 eree of the unit points=6 If the ratio is<1 pomts-I Z Un�nzed,herbaceous plents>2/3 nrce of unit poinis=6 Aedal hoto or ma showin avere e widths R 3.2 Characteristics of'vegetation that slow down water veloci[ies during tloods:Trear Figure_ Unprnzed harbacaous pinnt�>I C.!erea of unit points^'3 � R Iqrge woody d¢brls as'forest or shrub". Choose the potnfs approprlate for the best 7'rees,sluubs,und ungazeA herbecaous<1/3 area of unit points-0 descnptton.(polypans need ro have>90Yo mver et person height NOT Cownrdin cle.veel Aedel hoto or me showin ol ons of dlMuront vo oM[ion s Forest or shntb for>I/3 aree OR harbeceous plants>?/3 aroa mts= R Add fhe points in(he bosca nbove ��,' I Foreat or shrub Por>1/10 nrea OR herbaceous plents>1/3¢rea pomts=4 jt R 2.Uoes the wetland unit heve the oonortunitv to[mprove water quellty? (set p.53) Vegetation doos oot meet ebove critarie points�0 � Answa YES if you know or believe thrne arc pollutents in p{oundweta a sud'aca weter Aerial hoto or ma ahowin ol one of dkfareM ve atation s � �� coming into the wetland thnt would otherwix roduce wnter qualiry in streams,leke+or R .4dd the poinra in the boses above �— �_—� groundwater downgredient from the wetlend?Note whtch ofthe fallowrng condttions R R 4.Dnes the wetlend unit have the onnortunitv to reduce floading and erosion? (see p.57) prnvide the sourrea ofpollutarttr. A unit may have pallu�ants coming from severa! Mswer YES if the imit is in n location in ihe watershed wltere tha flood storage,or aoureea,fnU any single source would qvaltfy aa oppartuniry. reduction in water velociry,it provides helps protect downsfieum property and sqiu�tic �3ruing in the wat(md or within 150it resources from flooding or excessive and/a eroaiva tlows.Note which of d�e fvf(owirtg — Llnhented stormwxter diachargas to wetlend cortdltlons apply. — Tillad fields or orcharda within 150 feot of wetlend 1�'Itiere ere human muctures and nctivities downstream(roeds,buildings,bridges, — A stream or culvert Jischacges into wetland thxt dreins developed areeq fertns)thet can bo damagad by ilooding. �esidenfial areas,fatmed fields,roads,a dear-cut logging — 'Ihere ere netural resources do�msheam(e.g.salmon reddx)thet can bc damaged �ResidenAnl,urban areas,golfcourses nra within 150 ft of wetlend by floodinq — The river or stream linked to the wetland has a contributing basin whae human — Other�________ __.,___, ._ ,. �_ multipf ier activitics have raisul lovels of saliment,tuxic compounds or nunients in the rivcr (�1 nawer NO rflhe major aource of water to the wetland is controlled hy a reservoir or Nre water a6we xtandards for weter quelity multiplier wedand it h a o the aedea afa dtkeJ Z — Other 'Z YES ultiplier i NO muitiplier is I YES mu ' lier' NO multiplier is 1 ---- R TOTAL -Hydrologic Functlons Multiply lhe seore f'rom R 3 hy R 4 / </ R TOTAL-Water QualIty FtincNons Multiply the scorc Gom R 1 by R 2 zD Add score to ta6le on p.1 � �� Add score fo table on .1 Commeots Commen[s NcHanARn�ingFnrm-weatemWaahinginn 7 August2(N)4 Wet6ndHatingForm-weaternWaehingtort 8 Auguat2004 venion 2 Updated with new WDFW definitioro Oct 2008 vcniun 2 Updited with new WDFW definiuons Oct 2008 Nctland name or number Wetland namc m number I 7he.se questiores apply to-wdlands of af!HGM clusses. Points �i�.a.�,icrsoers�o�otn8b��acg�Se�R �6� ig�r�_ (onlyi.are Decidn from the diagams belaw�.fiather interspersion between Cowardin vegetation HABITAT FUNC'ITONS•Indicators that unit funatib�Yo provide ittipottant habiffit pcb� classes(descri6ed in H 1.1),or the classes end unvegetated areas(can include open water or mudflfl[s)is high,medium,low,ornone. H 1.Dues the wetland unit have the tno entiul to provide hebitet for many species? H l.t Ve�otntionsfi�cmre(�rep.72J Figure_ �O Check rhelypes ojvegetation clatsea presenr(as defrned by Cowardin)-SITe threshold jor each � cla.es ts'/.acre or more than 1�of tAe area!f unil is amal/er than 2.S acres. � ., Aquetic bed Ewergent plsnts �c�ub/ahrub(erees where shntbs have%30%cnver) b None-0 points ow�1 poi Moderatc-2 points ✓F'orested(areas where tras hevc>30%covar) �°`+• � `��!r�� 1 /fthe unit har af�rexted elass ciuck tr �� 'fht fotested cless hna 3 out oC5 strate(cenopy,subcennpy,shrubs,herb8ceou�, � moss/ground-cover)that eech covnr 20%within�he forested polygan .� Add�he n:�mber ofvegetanan snuctures ihal qaalify. Ijyou hme: � 4 shucmros or morc points�4 Map of Cowartlin vegetatlon alasses 3 structuros poinn-2 � 2 siructuros points�1 � � � [riparien braidod channels] I structure ints=0 High =3 points H 1.2.H�drvneriods(see p.73) Figure_ NOTE:lf you have four or moro ctasyes or flvee vegetation classes and open water � Check rhe rypes oJwater regtmer(lrydraperiodsl prescmt w7thin the wadand The waler the ratin is alwa s"hi ". Use ma o!Cowerdin ve etatan elasses regime har 10 cover more rhan 1056 of fhe wetland or�/�acre to count(see trrxr jor {I I.S.SpOC16I H6bltflf FCAh1i05 �SLL�J.��f desenpriona ojhydropertodaJ CHeck�he habJratfearures thnr are present in the wetlarrd The mimber ofchecks(e d�e Permnnently flooded or inundatod 4 or moro rypes present points�3 rrumher ofpointr yrn�put into the rteet cnlumn. =Seasonally flooded or inundated 3 types present pointa=2 _�ge,dnwned,woody debris within the wetlnnA(>4in.diameter and 6 ft long). Occa.eianally flooded or inundated 2 types presrnt point=1 Stending mags(diameter at the bottam>4 inches)in tha wetland �SeNra[ed only 1 type preaent poinLc=0 — Permanently flowing sireem or river in,or edjacent to,the wetlanJ _Undacut banks ere present for at least ti.6 ft(2m)and/or overhanging vogetation extands at �Seesonnlly flowing slream in,or adjflcrnt to,the wetlnnd leaffi 33 fl(]m)ove�d st[enm(or ditch)in,or ccmtiguous with thn uni[,for nt lenst 33 ft _Lakrjringe wetland-2 polnts r (I Om) Freshwa(er lidal wtlGtnd-2 polnls Map of hydroperiods _SMblt steep banks of fine mnlerial Ihat might be used by beaver or muskral Rn denning (>70dcgrce slopc)OR signs of recent beever ac[iviry nre present(cur shn�ba nr�rees that H 1.3.Richness of Yl�.t 3necies(ste p.75) _ � l�ave not ye!trarrred grey/brown) Count tho numba of plant specios in thc wetlend that cover at least lU ft. (dt/ferenr p�rchea At laaet%.acre of thin-stemmed persishnt vegetation or woody brenches are present in areas of the sarKe epecies cm!be combined to meer rhe rtze 7hreshold) ihet nre pamanenHy or seesonelly inundnted.(srructurer for egg-(aying by ampldbians) You do not have to nome Ihe specter. ✓Invasiva pinnts caver less ffien 25%of tha wetland eree in eech strntum nf plents Da not�rtclude Euraslan Mi foil,reed canarygrarr,purple loosestrije, Canadian Thistle — Z If you countad: >19 species points=2 NOTF_:The 20%stated rn early prinlings ofthe manua!on puge 78 tt an error. L/st species below tjyou wanr to: 5-19 species s- H 1.TOTAL Swre- potential for providing habitat � /_ � <5 species �iirtS'�--0 Add the scores om tll.l,H1.2,Nl.3,H1.4,III.S � «� � Comments r � Total for pegc� WetLndRatingForm-weeternWoshington 13 Augtta[2004 We�landRatingForm-weetemWashington 14 puguxt2004 venion 2 Updatcd with new WDFW definitiom Oct.2008 vcninn 7 l;pdatrd wi[h ncw WUPW dctinitin v(lct 700R Wetland name nr numba W'ctland nama or numbcr__._ H 2.3 Near or ediAcent to other p iot rin�hebRats listal bv W1�1W(see new ared crm�pMe H 2.Does the wetland unit have the opportunity to provide habltat for many epeclrsR descripliores ojwDf�7Ypr'wray hobuats,and the canv6es in whirh Ihry ean he jound in H 2.7 pyt�g(seep.80) Flpur�_ lhePllSreparr hfln://rvdlw.warov/hnh/nhdi�tJmreJ Chooae ihe descrtpri��n fhar bt.rt represents condmon of buJf'erajwerland unte The hlghear scoring Which of the following priority habitats ue within 33Uft(100m)of the we�land unit7 NpTF_:the cNterion thnt opp(eea�to 1he we�land 7a to be ueed ln�he ra�trtg.Seo�az�for definttfon oj connecMons do not have ro be rela�ively undisturbed. "undisrurbed" _�apen Stonda:Pure or mixed stands of aspen greeter tlian 0.4 he(1 acre). Oiodlversity Arces and Corrldnr+:proas of hebitet that are reletively importnnt to vuiws — 100 m(330ft)of relntivoly undisNrbed vegeteted ereas,rocky�ra�s,or open weter>95% species of netive fish and wildlife(ful!descr�pfionr ir.WDFW PXS reporr p.IS7). of oiroumCa��noe. tio shuctures ere within the undixtu�bed pM of buffa. (relatively �rbaeeoua Balds:Veriable size petches of�ass andl Forbs on shellow suils uver beJrcek. undisturbod��lso menns no-grazing no landsceping,no daly human use) Po�nts-S Old-Qrowth/Matun forosts:(Old-erowth west of('ascade cres�l Stends of nt leest 2 troe — 100 m(330 Y3)of reletivcly undisntrbod vegchted areas,rocky ereas,or open water? species,fonning a multi-leyared canopy with occssionnl smal!openings;witli At leest 2U 50%circumference. Polnt�-4 treeyRta(B trees/ecro)?8l cm(32 in)dbh or>200 yaers of ega (Mahire Ic�reslg) Stnnds — 50 m(17DII)of reletively undisNrbed vegetaled amas,rc>cky ereas,nr open weter�95% with nvorage diemetars exceeding 53 cm(21 in)dbh;cro�m cover may be lesa that 100%; circumferetu;e. po�s s 4 crown cover mey be less thet 100°%;dceey,decndrnu:,numbers of snags,and quantity of — ]00 m(330ft)of relatively undiaturbed vegetated arees,rocky�reas,a open weter>25% latge downed mnterial is generetly less than thet found in old-growth;RO-200,��evs old cimimference,. P��a�3 west of the Cascede cres[. — 50 m(170ft)of relatively undishubad vegetatcd ercaa,rocky ereas,or open wata fa> OreRnn white Oak: Woodlanda Stends of purc oak ar oek/conifar essocietions avhere SO°o circumtl'erence. Poinb-3 —�cmopy coverege of the oak componcnt is impor�ant(,�ufl dercripriona in WDF'�V'PNS If buffer doee not meet arry of the crit�rfs above �porr p.I58). — No pnved arcas(except pnved trails)or buildings within 25 m(80tt)of wailand>95% _NLperlan: The erea ndjecent to equetic systertts with tlowing water that contnina��loments of circumferrnce. Light to moderete grazing,or lewns aro OK. Polnb-2 both equstic and terrestrixl ecosystems which mutually intluence eech ather. — No pevad e�+:as or buildings within SOm of wetlend for�SO%cimumference. � '�•� _�V�atalde Pnirlea: Habaceons,non-&irested plant emnmunities that can either tnkn tha LigM to moFlarntn�v.ing,or lawn�are OK. � fortn of e dry prairie or a wet preirie(ful/descrlptions in WDFW PHS reporr p.!61). — Heavy grezing in buffer, Polnts�1 _Instnsm:The wmbinauon of physicel,biological,enN chanical processes and¢onditions — Vegeuted buffers nre<2m wide(6.6fl)for more than 95%of the circumfaronce(e.g.titled thet intttact to provide funetionel life hietory requirements for instream fish and wildlife fields,pevin3.besalt bedrock emend ro edge of wedand Pointa�0. —7 «�«g• — BuRer daesmot meet eny of the criuria ebove. Polnt��1 �i _Neanhorc:Reletively undisMbed nearshore habitets. These include Cosstal Nearshore, Asrial hoto showl bufTan Open Caast Neershrne,and Puget Sound Nearohoro.,(ju!!deacript(ona ojhabirdrr and rhe H 2.2 CorriAors and Connections(setµBI) deJimnon ojrelative[y tmdlsturfred are in WDFW rep�rt:pp.167-169 andg/osrary m H 2.2.1[s thn wetland pert of n rolativoly undisturbed end unbroken vege�ted ecxTidor Appendix AJ. (eitha ripxrian or upland)that is at least L 50 ft wide,hes at leaat 30^h cover of stwbs,forest Csve�:A naturally occurring cavity,recess,void,or system of interconnected pnssnges undcr ur netivn undisturtred preirie,that emtnxts to estusries,other wetlands or undisturbed the earth in soils,rock ice,or othtt geological formMions and is la'ge enough to wn�ein e uplands that a�e at Iaest 250 naex in sixe7 (dams in riparian corndora,Jreavdy used grave! human. rocds,paved r��ads,or¢conslderad 6r¢aks 1x tha corndar). _C11Rs:Oreata then 7.6 m(25 ft)high end cecurring befow 5000 ft. YGS�4 polnta (go ro H 1.3) �"O�go tn- 22 Talw:Homogenous veaa of rock rubble ranging in avurego siu 0.t S-2.0 m(0�-6.5 R), H 2.2.2 Is the wvetland pert of e relatively undisNrbed and u vegetated cortida cotnposed of basalt,andesite,sttd/or sedimenta[y rouF:,indtiding riprep slides end mine (either ripannn or uplend)thet is at leest SOtI wide,has at leeri 30%cover of shru6�or tailinge.May be aewcieted with cliffs. forest,and connects to eaNeries,other wotlends or undi�turbed uplends that ere et leest 25 . _Snage tnd Log�: 'I'rees ere con�idered snegs if they nra deed or dying and axhibit sufficient acros in sicc7�OR n 4ake-fringe wetlend,if it does not hnva an undisturbad wrridor ns in decny cheractaristics m rnehle caviry exeevetior✓urelhy wildlife.Priority snegs have fl the question a6me? diemeter nt brenst height of>S1 cm(20 in)in westem Washington nnd are>2im(G.S ft)in YFiS-2 polnts (go ro H 1.3) NO-H 2.2.3 heighi. Priority logs are>30 cm(12 in)in diameta ut the largesi end,snd?6 m(20 R) H 2 2.3 Is the�vetland: �O"g� within.'�mi(8km)of e breckish or uli wnter aetunry OR If wetlend has 3 or mon priority habitats�4 po6ite within 5 mi of n lagc field or pasture('40 ecees)OR / 1(wetland has 2 priaity habitats=3 potnt� within D mi greata thnn 20 ecres? ! If wetland has 1 priwiry hnbitat-1 painl No hebitau-0 points YF� 1 NO-0 Inb Nore.•A!!vagera�ed werlandr are by deJtnitlon a prJo�l.y habimr but are not tncluded in th�s � liat. Nem6�x�etlara[r ore addre.rsed in uestion H lrl) "1'otal for paµe � A'ctland Rating Form-weekrn R'aehington IS Auguet 2004 Wct4nd ILling Furm-wee�crn Wyehingtun 1! Augu+t ZO(14 vereinn 2 UpdateJ with new\b'DFW definitione(kL 2008 vcnion 2 Updalcd with new WDPW'definitions Oct 2008 I R'etland namc or number R'etland name or mm�bcr L CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS H 2.4 Wcllend I,nnM;cno�(choore�hc ont destriptiort of�he landscape aroued 1he wdland that best firs)(.see p.8f) Thare ue at leasi 3 other wetlmds within Y'�mile,end the connectiofls betweea ihem ere Please determine if the wetlaxd meets the attributes�lescribed belo„�and circle the reletively undish�rbed(light gtazing boC,vern wetlends Ol�as is I�ka shoti wilh aomc pppropriate answers ax�!Category. bneting,but oonnections should NOT bu bisected by peved roads,ffill,fields,or vthar development. �ints-5 W�►Aod"I'ype Cateqory The wetland is laka-fringe on a leke with linle disturbence md ficrti erc 3 other lakafringe Check off mry crilena that apply[o lhe welland Circle Ihe Calegory wherr!he weflnnds within h mile �ints�S There ere at ler�t 3 other wetlands witktin'/,mile,PiTC the connectitms batwoert them nr a ro riate cri(oia ax met. disturbai �n SC 1.0 Estuerine wetlends(set p.8� The wetiand is 7.ake-fringe on a lake with disturbance and thera ere3 other lekafringo Does the wetland unit meet the following criteria for Estuanne wetlancls? wetland within'/:mile poinri=3 Thcrc is nt lasst 1 wetlend witl�in'/,mile. points=Z —The dominant water regime is tidal, Thae are no wotlands within 15 mile. points=0 — Vegetated,and 3 — With a salinity greatcr than 0.5 ppt. H 2.TbTAL Score- opportuniry for pmviding habitat 1 I YES- Go to SC 1.1 NO_ Add the scnre.sfrorn fl?.I,H2.2,H23,H2.4 � _�__� SC 1.1 Is the wetland unit within a National Wildlife Refuge,National Park, Tc)TAO. Cor H 1 from page 14 G National Estuary Reurvc,Natural Area Presen�e,State Park or F.ducational, Ca�•� Environmentnl,ar Scienfific Rescrve designated under WAC 332-30-151 T Totel Score for Hebitet Funcfione -add the points for H 1,H 2:and record the rcsult on YES�Ca[e orv 1 NO o to SC 12 P•�- �� SC 1.2 Is the wetlend unit at lesst 1 acre in siu and mcets at least two ofthe following three conditions? YES-Category I NO-Category II Cat 1 —The wctland is relatively undisturbed(has no diking,ditching,filling, Cat.11 cultivetion,grezing,and has less then 109 e covcr of non-netive plent species. If the non-nalive Spartina spp.em Uic only species thxt cover more then 10°%of the wetland, then the weUand should be givcn a dual Dual rating(UII). The aren of Spartina would be reted e Category II while the rating reletively undistivbed upper marsh with native species would bc a ��I� Category I. Do not,howevcr,exclude the area of Spartina in determining the size threshold of 1 acre. —At least%.of the]andward edge of the wetland has a l00 R buffer of shrub,fo�est,or un-grazed or un-mowed grasslend. —The wetland has¢t leaet 2 ofthc Collowing feahues�tidal channels, depressions with optn water,or contiguous f'reshwater wetlands. Welland Rating Porm--weefem Waehington 17 Augue[2004 WetUnA ILting�orm�we�tern Waxhington l8 Augttnt 2(H14 venion 2 Updatcd with new WDPW defini[iona Ck4 2008 venion 2 Updated with new WDFW dcfinifio�u Oc�200R