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Home My WebLink About03835 - Technical Information Report r' ��!l- ---� TECHNICAL INFORMATION REPORT for MAERTINS RANCH 1508 Ilwaco Avenue NE Renton,WA g A. Jp I � F N'A S J �F: Nf.4-jr o� ' r � � � � ~ O ��' `� �`j- R �l R� ��. ` i\i. L � � 1 '�"' � I� DRS Project No. 14103 Renton File No. U15-001308 & B15-001797 �� OwnedApplicant II Albacore —ACH, LLC 9675 SE 36th Street, Suite 105 ��t� I Mercer Island, WA 98040 ��IQF ��,0 I Report Prepared by ��,a �015 I � � �� N D. R. STRONG Consulting Engineers, Inc. ��{•1��1� 620 7 Avenue pS� Kirkland WA 98033 (425) 827-3063 Report Issue Date July 6, 2015 �- ��2015 D. R.STRONG Consulting Engineers Inc. TECHNICAL INFORMATION REPORT MAERTINS RANCH TABLE OF CONTENTS SECTION1.......................................................................................................................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 I Off-Site Analysis.........................................................................................................13 � SECTIONIV ..................................................................................................................14 Flow Control and Water Quality Facility Analysis and Design....................................14 �, Existing Site Hydrolo9Y �Part A)..............................................................................14 �I 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 Bypass Hourly Time Step Modeling Input:..............................................................19 ' Bypass Hourly Time Step Modeling Output: ...........................................................19 Performance Standards (Part C)................................................................................21 Flow Control System (Part D).....................................................................................21 Flow Control BMP Selection ...................................................................................21 Flow Control Facility Design Output........................................................................22 Water Quality Treatment System (Part E)..................................................................29 SECTIONV ...................................................................................................................31 Conveyance System Analysis and Design.................................................................31 Developed 15-Minute Time Series.............................................................................31 Developed 15-minute Time Step Modeling Output: ................................................32 SECTIONVI ..................................................................................................................41 SpecialReports and Studies......................................................................................41 G2015 D. R. STRONG Consulting Engineers Inc. Maertins Ranch Page i of ii Technical Information Report City of Renton SECTIONVII .................................................................................................................42 Other Permits, Variances and Adjustments................................................................42 SECTIONVIII ................................................................................................................43 ESC Plan Analysis and Design (Part A).....................................................................43 SWPPS Plan Design (Part B).....................................................................................44 SECTIONIX ..................................................................................................................46 Bond Quantities, Facility Summaries, and Declaration of Covenant..........................46 Stormwater Facility Summary Sheet..........................................................................47 SECTIONX ...................................................................................................................49 Operations and Maintenance Manual ........................................................................49 APPENDICES ...............................................................................................................50 Appendix �,A,� Legal Description..................................................................................50 Appendix �,B„ Bond Quantity Worksheet.....................................................................51 Appendix "C" Operations and Maintenance Manual...................................................52 Appendix ,�p„ CSWPPP..............................................................................................53 Appendix "E" Declaration of Covenant.......................................................................54 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..............................................................................16 Figure 6 Post Development Area Map...........................................................................20 Figure 7 Detention & Water Quality Facility Details .......................................................30 02015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page ii of ii Technical Information Report City of Renton SECTION I PROJECT OVERVIEW The Project is the subdivision of one existing parcel zoned R4 (4.079 ac. total) into 13 single-family residential lots, per the City of Renton's (City) subdivision process. The Tax Parcel Number is 0323059021. The Project location (Site) is 1508 Ilwaco Avenue NE Renton, Washington. The Project will meet the drainage requirements of the 2009 King County Surface Water Design Manual (Manual), as adopted by the City and the 2009 COR Amendments. PREDEVELOPED SITE CONDITIONS Total existing Site area is approximately 177,683 s.f. (4.079 ac). Total proposed Project area is 177,683 s.f. (4.079 ac). The Parcel is currently developed with one single-family residence, garage, barn and a gravel driveway. The remainder of the Site is pasture, scotch broom, and scattered trees. The 4.079 acre parcel is situated on a slope that discharges runoff to the northeast and southwest. However, upon further field inspection it appears that the high point is a consequence of prior Site grading to create buildings pads for the existing garage and barn on the Site. Therefore, for purposes of this analysis, the Site will be considered to be within one TDA and all runoff will be conveyed to the northeast. For the purpose of hydrologic calculations, the entire Site is modeled as till forest. DEVELOPED SITE CONDITIONS The applicant is seeking approval to create 13 lots with lot sizes ranging from approximately 8,050 s.f. to 10,985 s.f. All existing improvements will be demolished or removed during plat construction. The 13 single-family residences combined with their driveways (includes turn around easement) will create approximately 55,562 s.f. (1.28 ac) of impervious area. The proposed 53-foot right of way will be improved with 26 feet of pavement, vertical curb, gutter, 8-foot planter strip and 5-foot sidewalk. The half street frontage improvements on NE 16t" Street will consist of 11.5 to15.5 feet of new pavement (27.5' total pavement width west of the proposed road intersection with NE 16t" Street and 37' total pavement width east of the intersection), 1,600' of vertical curb, gutter, 8-foot planter strip and a 5-foot sidewalk. The improvements from right-of ways will add approximately 41,603 s.f. (0.95 ac) of impervious surface. The Project will result in a total of 2.32 ac of new impervious surfaces The remainder of the developed Site (1.76 ac) will consist of landscaping and lawns. Approximately 3,100 s.f. will bypass the facility (90G sf i«�pervious, 2200 {�erviousj due to topographic constraints. This area meets the requirements of Section 1.2.3.2.E of the Manual with a 100-year peak of 0.024 cfs. The runoff converges with the discharge of the facility almost immediately and will not create an adverse downstream impact. Facility design will provide compensatory storage such that the predeveloped discharge rates are not exceeded at the downstream point of compliance. The Project is required to provide Level 2 Flow Control and Basic Water Quality treatment, per the 2009 KCSWDM (Manual). All surface water runoff from impervious surfaces will be collected and conveyed to a storm detention vault followed by a storm 02015 D. R. STRONG Consulting Engineers Inc. Maertins Ranch Page 1 Technical Information Report City of Renton filter located in Tract "A". The detention vault will discharge to the conveyance system in the northern flow line of NE 16'h Street (NDA 2 downstream path), see Section III. NATURAL DRAINAGE SYSTEM FUNCTIONS There appears to be a highpoint on Site that bisects the Site into two drainage basins. However, u on further field ins ection it a ears that the hi h oint is a conse uence of p p pp 9 p q prior Site grading to create buildings pads for the existing garage and barn on the Site. Therefore, for purposes of this analysis, the Site will be considered to be within one TDA and all runoff will be conveyed to the northeast. The vegetation consists of pasture, scotch broom, and scattered trees. Site runoff travels northeasterly and sheet flows off the Site to the conveyance system in NE 16th Street. A review of the SCS soils map for the area (see Figure 4, Soils) indicates Alderwood gravelly sandy loam with 8 to 15 percent slopes (AgC). 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 King County iMAP aerial topography, City of Renton Mapping Application and imagery and conducted field reconnaissance to evaluate conditions and potential problems. There are two high points on Site which prevent any runoff from neighboring properties entering the Site. There is no upstream tributary runoff entering the Site. 02015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 2 Technical Information 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: � Albacore —ACH, LLC Maertins Ranch ' Address/Phone: Location: I! 9675 SE 36th Street, Suite 105 Township: 23 North Mercer Island, WA 98040 Range: 05 East Section: 03 Project Engineer: Maher A. Joudi, P.E. D. R. STRONG Consulting Engineers Inc. Address/Phone: 620 7th Avenue I Kirkland WA 98033 � (425) 827-3063 Part 3 TYPE OF PERMIT Part 4 OTHER REVIEWS AND PERMITS APPUCATION � Subdivision ❑ DFW HPA ❑ Shoreline ❑ Short Subdivision Management � Clearing and Grading ❑ COE 404 � Rockery ❑ Commercial ❑ DOE Dam Safety � Structural Vault ❑ Other: ❑ FEMA Floodplain ❑ Other: ❑ COE Wetlands Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community: East Renton Plateau Drainage Basin May Creek ��2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 3 Technical Information Report City of Renton I 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 8-15% Slight Slow ' (AgC) �Additional Sheets Attached: SCS Map and Soil Description, Figure 4 ' Part 8 DEVELOPMENT LIMITATIONS ' REFERENCE LIMITATION/SITE CONSTRAINT I, � Level 1 Downstream Analysis 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 preservation �Cover Practices areas �Construction Sequence ❑ Other ❑ Other �2015 D. R. STRONG Consulting Engineers Inc. MaeRins Ranch Paae 4 Technical Information Report City of Renton Part 10 SURFACE WATER SYSTEM ❑ Grass Lined ❑ Tank ❑ Infiltration Method of Analysis: Channel � Vault ❑ Depression KCRTS � Pipe System ❑ Energy Dissipater ❑ Flow Dispersal Compensation/Mitigatio ❑ Open Channel ❑ Wetland ❑ Waiver n 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 to the conveyance system in NE 16th Street. 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: Temp. Cul-de-sac Easement Part 13 SIGNATURE OF PROFESSIONAL ENGINEER I or a civil engineer under my supervision have visited the Site. Actual Site conditions as observed w e incorporated into this worksheet and the attachments. To the best of my knowle the information provided here is accurate. �� 7' ��• � Signed/Date , � , � � � i _ _ _.__ _ � �� _ �.� ._ FIGURE 2 VICINITY MAP _. �,KL�oiL '�x�y� Knbti �7dMm + ILa1Dif � E/ODLt , 11L.y�pA �x ��4 �C� \` ��a 3� � ` R�4 � ,��" x �cnsrar f y� � � � w[aoR � � - � �,�., -�1 . � � 3�G � � �T,.n � �..� .Ean.w � 1 � rcwr«sr 4 � raam�n � R1 C � �� Rj�i/ � a �, i� ,wc,arxsr � �0,4 � y aE�n�sr K MM CA � � �` � ��C� �y�MG� Y M� � A 1�E�N � � "� Y SITE ,�,n�R � Renton � ��, Y w � � ,t;�C�, � �£n" 1 g `s � �, g � �,�4� i � �a � 5 �� ` � � :� _- � . � � f r � 5 , � - t - �.: Y � - `'�" �✓ � � � , �Qo .A �.l �j .. �� . � �t��5y" 5� F � 14UMR �,P� ��.N � � �p �E1]Iflti � _ i g 1Eqlllff , "_ IE�ANlf � � 2 � � r.:_:�;._�_-:t.,.._,'. �„�,.a R.{ �. -'��'SEIL,�.. ip�y� � RA� v� � �� j( . �`. R�4 :�rnMcr �� '•[ . ��_. SEI�lfMBT ` � is�an 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 liable for any general, special, indirect, incidental, or consequentia damages including.but not limited to,lost revenues or lost profits resulting from the use or misuse of the info�r�atian �o��tai,�d c�� tn��s r�sp F,.� �la c '�s r��s� o�ir=o��i�- �� r�r� , ��_i.�: e:�:ca�' t;� .� i _ , _ -��s;i�r c`K� : Cc.:��y. FIGURE 3 DRAINAGE BASINS, SUBBASINS, AND SITE CHARACTERISTICS 2015 D R STRONG ConsuLing Enq'n�er Inc f�iaertins Rao;:h Page 7 Technical In`orma;ion Repo� City of Renton i I I � I I I W I � q i W � . i I , I c, c, � Q ; 2 2 � 3 � y o � v�i � 2 � I �� .. O 2 4 � ,.. S I i O U Y �' I _, - , I a ? g , �_r I W � � � � W o � i � O (� _ � ' / O Wm �. � � . � .�A4i�'� ,,y,,, � _ __' .... ', f � :. - � i+ _ ' ^ � � ` . 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' i }� y . . ... . � .. ��RrCt-�-,��, � - NDA2 � �.. � "- _ �� Y �` < �� i'•. � < •;, � . ; ,,: � � � F�o w 1 ;�`4� �`�, ' � < Z � DIRECTION 1 �,�- -- - - = Z OO � i I _ (TYP.) { �^� 4 � � � � ' , \ I � � � Q = I ,�, i - o � � j � � ` _�, � �� , _ � � � � , II I J ��=- ; .�� - Q w � o i � r, . o I � ;' ,.` � � ,.,� . M m � z � _�.�, � � w i �. � _� � . �� , � � ��-�-_ �f� - - - - - - - - - - - - - - - - � � - - � . � � T � '� / . . - -- � � . \ . / , . � i � �� PoJP / � P�� / � / ��5� � � � N O RT H DRAFTEO BY. (�7V O O DESlGNED BY.• G / \ �� / GRAPHIC SCALE PRQAECT£NGJN££R: MAJ � / I � / ��P � \ \ / R / � 0 30 60 90 DA7E• 11.Q5�2014 \ CJ� � � � PROJECT NO.: 14103 1 INCH = 60 FT. �rcuaf: 3 R:\2014\1174773'�3�Drawings\Plots\,Reoort Figures�35A5�.vMAP14703.dwg 7/6/20�5 /�:59:59 AM PDT COPYRIGHT�2G14, G.R. STROVG CONSULT',VG ENGMEERS INC. FIGURE 4 SOILS j� ��P ! . • g � ..-7c `i_.::C `_'-':Y� K::9] SE,I':C 561:� r:3'} �s .�� . � . . .,�1 ' ". _ __ � Q'bZTv �¢ ��`T�'. �... T t"'v' f� ��'� �.'; y� .� � p ; �� .. �.a_ �; - � � �'_� S. �.�b`�i"'� �.. a^P� ^/<I . ' �y S� 4 �ii ^p�r�t "t � � �-� � ��5"-ro :�!� ¢ • � �� `%�" . . � i - Yr`_. Ji� °�� "�' _ ._ - �'L �,� 'i,y� '�' . , + _. . .. .. , . � „ . A i J,,�M_ ��M .�.�'. ' ��! }� � �%r ;v � }' - 1/� f� _ �' . . _ � I r`��t ..d ;� � K.. �+ � .c� �`..�; �`� - > :� i �' � �_ � � �� _ ,, � - �� '` � _ �_�'�� _...r� _ ��e ��. �_ � ��'° : 9.. "^�v." . . _ � �` L � ��I � �% �- _ �^ __ �.�;ti :_ ',� " �� : � ' L y _ ,<, r- � � �,,,;:,,K- "°� �; ,�:,'� `: g f ' .�,�� - � - .�a:.:: �� ;�' ,� tr � _ � : � ;� � .`��,�.: �.•"�-v �:;�- '�_ 1+�'aF'.' .• Y Y � ..� .. -. + � _ F 4 1".'t t -j ,e S ' _ r 1 T ' �� s �i ?�S �p (r _ � � b �� :�� N k' t �� y' 3�..� 4�� ;� . . !°� `4 . t ' q� ' ��-'f •� �• k '��f:� . .. : ��' " � ;� '� . �'�, ��--¢s�P ,. 0 1 � s'`�^ ., �F _ _ Ki k �'�'' ��,k;J' � ! " � � �. v'" _ � '4• - + , ?�� t "'7�'' t�w'* `�� t �� + � � ! 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Maertins Ranch Page 8 Technical Information Report City of Renton i I AgC—Alderwood gravelly sandy loam, 8 to 15 percent slopes Map Unit Setting • National map unit symbol:2t626 • Elevation.•0 to 1,000 feet • Mean annual precipitafion:20 to 60 inches • Mean annua!air temperature:46 to 52 degrees F • Frost-free period: 160 to 240 days • Farmland classi�cation:Farmland of statewide importance Map Unit Composition • Alderwood and similar soils:85 percent • Minor components: 15 percent • Esfimafes are based on observations, descriptions, and transects of the map unit. Description of Alderwood Setti ng • Landform:Hills, ridges • Landform position(two-dimensional):Shoulder • Landform position(three-dimensional):Nose slope,talf • Down-slope shape:Convex, linear • Across-slope shape:Convex • Parent maferial:Glacial drift and/or glacial outwash over dense glaciomarine deposits Typical profile • A-0 to 7 inches:gravelly sandy loam • Bw9 - 7 to 21 inches:very gravelly sandy loam • Bw2-29 to 30 inches:very gravelly sandy loam • Bg-30 to 35 inches:very gravelly sandy loam • 2Cd1 -35 to 43 inches:very gravelly sandy loam • 2Cd2-43 to 59 inches:very gravelly sandy loam Properties and qualities • Slope:8 to 15 percent • Depth fo restrictive feature:20 to 39 inches to densic material • Natural 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 wafer table:About 18 to 37 inches • Frequency of flooding: None • Frequency of ponding:None • Available waterstorage in profile:Very low(about 2.7 inches) Interpretive groups • Land capability classification(irrigated):None specified • Land capability classifrcation(nonirrigafed):4s • Hydrologic Soil Group:B • Other vegetative classification:Limited Depth Soils(G002XN302WA), Limited Depth Soils(G002XS301 WA), Limited Depth Soils (G002XF303WA) Minor Components • Everett • Percent of map unit:5 percent • Landform:Moraines,eskers, kames • Landform position(two-dimensional� Shoulder. summit • Landform position(three-dirnensionali_ Nose slope • Down-slope shape:Convex • Across-slope shape:Con�ex • Other vegetative classifrcation:Droughty Soils(G002XN402WA) Indianola • Percent of map unit:5 percent • Landform:Hillslopes, kames,eskers,terraces ��2015 D. R. STRONG Consulting Engineers Inc. Maertins Ranch Page 9 li Technical Information Report City of Renton I • Landform position(fwo-dimensional):Backslope, summit . Landforrn posifion(three-dimensional):Side slope, crest, tread • Down-slope shape:Linear,convex • Across-slope shape:Linear,convex • Ecological site:Thuja plicata-pseudotsuga menziesiilgaultheria shallon/polystichum munitum (F002XN903WA) • Other vegetative classification:Droughty Soiis(G002XN402WA) � Shalcar j • Percent of map unit:3 percent • Landform:Depressions • Landform position(three-dimensronal):Dip • Down-slope shape:Concave • Across-slope shape:Concave • Other vegetative classification:Wet Soils(G002XN102WA) Norma • Percent of map unif:2 percent • Landform: Depressions, drainageways • Landform posrtion(three-dimensional):Dip • Down-slope shape:Concave, linear • Across-slope shape:Concave • Other vegetative classification:Wet Soils(G002XS101 WA) 2015 D R STRONG Consulting Engineers Inc Maertins Ranch Page 10 Tecr��a! I�fcrra'ic� R2�� C�ta o`Re�ton 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: There appears to be a highpoint on Site that bisects the Site into two drainage basins. However, upon further field inspection it appears that the high point is a consequence of prior Site grading to create buildings pads for the existing garage and barn on the Site. Therefore, for purposes of this analysis, the natural discharge location is at the northeast corner. • C.R. #2 — Offsite Analysis: Analysis is included in Appendix A. 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 vault 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 and 100-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 may utilize splash blocks for basic dispersion, pervious pavement, or other BMP's found in Appendix C of the Manual for an impervious area equal to a minimum of 10% of each lot area. • 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- 'i 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 �i 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. See 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 02015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 11 Technical Information Report City of Renton � two-year period following posting of the drainage defect and maintenance financial guarantee. • C.R. #8 — The Project is located in the Basic Water Quality Treatment area. A � StormFilter will accommodate 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. ��, ��-2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Paae 12 Technical Information Report City of Renton SECTION III OFF-SITE ANALYSIS An offsite Level One Downstream Analysis was prepared by D.R. STRONG Consulting Engineers Inc. �' � � 02015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 13 Technical Information Report City of Renton 'IL LEVEL ONE DOWNSTREAM ANALYSIS for MAERTINS RANCH Preliminary Plat 1508 Ilwaco Avenue NE, Renton,Washington ��,� � x i sf��LjJ � .t�._ I � i � o� � � . ti T �; N � ��: ��C JQ�\'_�L``�� % , (�'f 1� DRS Project No. 14103 Renton File No. U15-001308 & B15-001797 Owner/Applicant Albacore —ACH, LLC 9675 SE 36th Street, Suite 105 Mercer Island, WA 98040 Report Prepared by � � D. R. STRONG Consulting Engineers, Inc. 620 7th Avenue NE Kirkland WA 98033 (425) 827-3063 , Issue Date: November 18, 2014 Revised Date: July 6, 2015 02014 D. R.STRONG Consulting Engineers Inc. LEVEL ONE DOVI/NSTREAM ANALYSIS MAERTINS RANCH TABLE OF CONTENTS TASK 1 DEFINE AND MAP THE STUDY AREA .........................................................1 TASK 2 RESOURCE REVIEW.....................................................................................5 TASK 3 FIELD INSPECTION .....................................................................................15 UpstreamTributary Area............................................................................................15 General Onsite and Offsite Drainage Description ......................................................15 TASK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS...16 Drainage System Description.....................................................................................16 DownstreamPath NDA 1........................................................................................16 Downstream Path NDA 2........................................................................................17 TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS.........................19 APPENDICES ...............................................................................................................20 APPENDIX A. Offsite analysis drainage system table & downstream map...............21 APPENDIX B. Drainage Investigation Reports..........................................................28 List of Figures Figure1. Vicinity Map ......................................................................................................2 Figure2. Site Map ...........................................................................................................3 Figure 3. City of Renton Topography...............................................................................4 Figure 4. Streams and 100-Year Floodplains and Floodway ...........................................6 Figure 5. City of Renton Wetlands...................................................................................7 Figure 6. King County iMap Erosion Hazard Areas .........................................................8 Figure 7. City of Renton Landslide Hazard Areas............................................................9 Figure 8. City of Renton Seismic Hazard Areas.............................................................10 Figure 9. FEMA — Flood Insurance Rate Map................................................................11 Figure 10 USDA King County Soils Survey Map ...........................................................12 Figure 11. Downstream Table........................................................................................22 Figure12. Downstream Map..........................................................................................27 02015 D. R.STRONG Consulting Engineers Inc. Page i Level One Downstream Analysis Maertins Ranch City of Renton DISCLAIMER: THIS REPORT WAS PREPARED AT THE REQUEST OF ALBACORE — ACH, LLC FOR THE 4.079 ACRE PARCELS KNOWN AS A PORTION OF THE SOUTHEAST QUARTER OF SECTION 3, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M., IN KING COUNTY, TAX PARCEL NUMBER 0323059021 (SITE). D. R. STRONG CONSULTING ENGINEERS INC. (DRS) HAS PREPARED THIS REPORT FOR THE EXCLUSIVE USE OF DRS, THE OWNER, AND THEIR AGENTS, FOR SPECIFIC APPLICATION TO THE DEVELOPMENT PROJECT AS DESCRIBED HEREIN. USE OR RELIANCE ON THIS REPORT, OR ANY OF ITS CONTENTS FOR ANY REVISIONS OF THIS PROJECT, OR ANY OTHER PROJECT, OR BY OTHERS NOT DESCRIBED ABOVE, IS FORBIDDEN WITHOUT THE EXPRESSED PERMISSION � BY DRS. TASK 1 DEFINE AND MAP THE STUDY AREA iThis 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 1508 Ilwaco Avenue NE Renton, Washington. See Figure 1, Figure 2, and Figure 3 for maps of the study area. I � i ,� � �I � 02015 D. R.STRONG Consulting Engineers Inc. Page 1 Level One Downstream Analysis Maertins Ranch City of Renton FIGURE 1. VICINITY MAP ;�i7eROR ._'•••+• �Jt�� r[s7bR u[�pg� . � MEaIOSf ' �102�DSf 1�1f1Oet � �,�C �,Y��S `'-.,.} *•,:l ��R $• y 'R,4 � � ��n r � <�� ' � �I : � ��a $ � � I b ; � � MFhhh � �r �llltp� � \ � �FntM0. I �• I�ENMSf I .� 4 R! � � 4 � � � Rj` � i� '�crMa � �q- � Ji sf�sr .�+m.tw ~! Y t � � ��ct ��cs r �1� 7� rh� .. M[Yf110. � /.�'�� ' � V MEf1fHR � Rerrton � � '�. �` '� _e:_ . . ' _: _ �J $ �°J "£�a � � � � � ' r � � 1 � � � �� ' - ' � � � � � -� � - �; � � � � � � 4�� --� � �--._� � ��,,�F° �� d ��,� - �� - � �� _ - � �� . �EUMR pM � �, � � � Y� '\ Z ��m14f �1=fMA � \ � 8' .._ .. IE 1SM lf z � �. - � `\ g�VMR R� � .. . RA�d ` RAd � �_ R,4 g,�.�. � ��n„� �� ` • ,sue 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 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. 02015 D. R.STRONG Consulting Engineers Inc. Page 2 Level One Downstream Analysis Maertins Ranch City of Renton FIGURE 2. SITE MAP �'i 02015 D. R.STRONG Consulting Engineers Inc. Page 3 Level One Downstream Analysis Maertins Ranch City of Renton � I � � . . � . 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STP,CNG Cv'JSJLTVG EVGI�=ERS '�NC. FIGURE 3. CITY OF RENTON TOPOGRAPHY siu :qf ,h� z � [T1! �� - �t*.S, .. �tE. ._._ . ' 2�. ,Ilri . � ' � y� � S311 , bs7 _ � � . �711 �. � ' . . 97p .. . �tN S>7Y �. . -. � 53T# `S)M� !sa . ,� ' . - . ad1 _ - . 6tN � . . . - " . S�zS � � 1710 , 5)M .�a73 - _ ' . � . - �� . _ ��=;- . � .a'�� . . taT2 ., 1B0T � 't � 1�1� ti1) S�.ti . � �Sp SSK S!!Q gyp 97a b . -; � 1qar, 'p1Q SSti 5Ib0 ' . y� .� 1tl06 .�. 9001 � # * �m� . 1qi� .. " - �r�" stee . � ��_d`, R'. , 1575 � � - '' - Site ` {-,- ' , �� F.T 3�V� -..�' � �ai;�.... ; ,5�, � � I]79 i t� � � ..i e � . .a+ - . . . - sf�s iS'tE . _ 15t! �Ss? . {'�� -'; ." . . ��. 3 � iSY. � r tma . '�` . est� •cia +w�a i >,�Y - . . 9DlT7 , �1Pft+ ; � . . µ � -180� . ��`ry 1 Sl f � � . Y - I �y t L1.1 � f � � i � t�� IN)i111 ' .. T� . ` , t�. .1` . I 1NOf '! S i.s,i* t , ' �.�,' -� � ?s' , . � ,� � � !t� �f� —_ + s.°' � �° �„ } ; s�u � �a ��` � ��.�tp - . . i�i t09ta �':M1 I � ..r _ �"� �. r .� . � .� - . �; � F� �.. � ' - �• � � - �� i� _ _. ,. � i.t,� 'i`; , i: , � �`i '�� aa i ��_. i •. yn �'aa� ! 1-"' Property �•. a��a �� f-'' �-�2��° I I : Cfty and County Eeund�r� �� '" � � Y'. �L �_. Other � ` ;`+'.s.;,� �. ��s _. SIw y,,, ._� ��-`�"..a,. _.� � ._. 4 . . � . -., � a� .. ... o �. �it3 � . l.� Crty cf r^.e�tor __ _ _ � 1'' � f` Garce:s � ''f" vas ase� ! i-_ Sensitive Arcas `'7f* i2rr �o� Ss25 -- 104'Primary 100`IntermeC at= d - 20"Priroarv 2Q'Intermed'a:e - 5'Primar� � 5'Intermed:ate -- 2'Pnmar� 0 12! 258� 2'Intermediate •R+ 02015 D. R.STRONG Consulting Engineers Inc. Page 4 Level One Downstream Analysis Maertins Ranch City of Renton TASK 2 RESOURCE REVIEW • Adopted Basin Plans: Fina!Adopted May Creek Basin Plan (Apri123, 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 of the distance downstream from the proposed project to the nearest critical areas. lncluded, are sections of the City of Renton Mapping Application and King County Sensitive Areas Folio which indicate the following: • Figure 4 Streams and 100-Year Floodplains and Floodway: There is one Type 4 stream, Greenes Creek to the north, with one mile of the Site. A 100-year floodplain is within one mile of the Srte where Greenes Creek outlets to May Creek north of fhe Site. • Figure 5 Wetlands: There are two wetlands along the downsfream path. • Figure 6 Erosion Hazard: There are no mapped Erosion Hazard Areas wrthin 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 path. • DNRP Drainage Complaints and Studies: As shown in Appendix 8, there are drainage complaints within 1 mile of the Site along the downstream path. Per discussion with King County, some of the drainage complaints along the downstream path are unavailable. • Road Drainage Problems: None noted. • USDA King County Soils Survey: See Figure 10. • Wetlands Inventory: The wetland inventory revealed no additional wetlands within the downstream path. • Migrating River Studies: None are applicable to the site. • Washington State Department of Ecology's latest published Clean Water Act Section 303d list of polluted waters: None listed along the downstream path. • King County Designated Water Quality Problems: None at this time. • Adopted Stormwater Compliance Plans: City of Renton Storm Water Management Plan; King County 2013 Stormwater Management Plan • Basin Reconnaissance Summary Reports: May Creek Current and Future Conditions Report (1995). �;2015 D. R.STRONG Consulting Engineers Inc. Page 5 Level One Downstream Analysis Maertins Ranch City of Renton FIGURE 4. STREAMS AND 100-YEAR FLOODPLAINS AND FLOODWAY ,� ; � � � ; � � ; � ; e _._.—'—..._�{ ;x.. � � . t t � I � �_ >_._._._,_ __1 i 3 i i � �'��. .,�.�.� ..._.±. 1 S Ite � t � � i + i � � � � `Gy a C Counry 2vundary � S C2!1H �,�City ct Re�lcr. P3rce s 1_._._._.�.,- . . _ _._._.._.._.. . __' -�[i��r � - _ _.:Fl�.r . F ...1rM f{oo� . � '_ '_st Floor �. �_j Otner&�Idi�gs '. Bu:!dl�g: �� –'.Smaifrce Areas .Spc=:a'=;xC H�_3rc�:e35�ICC ye3�f!oo-.]i � �Ftcc:er:a� �Sveams(Clasa��edi �Q7� 0 5�� 10�� —3 y��1 4 �2015 D. R.STRONG Consulting Engineers Inc. Page 6 Level One Downstream Analysis Maertins Ranch City of Renton FIGURE 5. CITY OF RENTON WETLANDS �. `,;. � ,,, ��'�`�� "` � __ _ s �. ,�� ' � �� :' �� . � �� - �� ` i i � � 4 ��„��`..�� . S ,�' `� y £, �i7 � �"'v§.- � �y s } �<:.� s. $ t'q .� ��e.� � � -� . -.. . ,.,�" ?2`-5a�.:.. . . •e+�"•`,..`� ..`',k�,`. � �.. i �:. . "�: ! • � 4 q��,.�,�. { �� . ��,.�.,,tiw.._.�.,._»� . � � � � j .,._._.� ....,_._._ . ...s . i k F ' Slte s f. F i � _ .— )i i . ! t t � I { t .. . .. ..:.. _.. � � �I � � � ' ; g __ 9 A _ 3 P. k" [` ._._._._._.,,... ... :...""._.._ _ _ .. f -; Property re.. (� City and Lounty Boundary Other �.� City ef�ent�+n � Parceis -�: Sensitive Qreas � 0 512 107]� ��Ne€lands �1 G2015 D. R.STRONG Consulting Engineers Inc. Page 7 Level One Downstream Analysis Maertins Ranch City of Renton _ ____ ___ ____ FIGURE 6. j KING COUNTY IMAP EROSION HAZARD AREAS , ,�w_ � � �-, �' ` `--- -.ti� i- Newcastie � «E�a �'''� �'`...�-_.� � � �� t �°} � _ , �� ,'' � . � ��R � � _ � ME1fIMR . =:5' KfSfifiT � / l \`� I ��SMh � ME75M3f f f � z I .. �E1(fMSf � � �ELfMQ �� ,,� ME?fMei .� w � /. \` . Z �f7(fNS� � �hE�mR � y ��q Q! - � I � �' MELRDlf ; z`� . ' � ME�iQSf �11E]]1DIIf �OG� f 7ENAIIf �.. S t� �4 � ��'_t .. / _'� �aca � in � � ''� � � � �� x �r� fx �1 ` � � t�f]ISf 0. $7 .� � _ +% I� Ancr ��. � ; �` ticmn I' ._. .:a I rEmWq� � y r MR = NFMMSf �MFHMa7 .. ,�. r . v. �� , �� s;:�,.�_ � � Rerrton �a ' � I � �i[ama � �O4 � m,. a � a�� '1 r � 5� �Rs � �+m�a � "i�M�� $ Y gtc' � � I �y = i: �F i rt"a+o N� �� i 2 ��. �cbmn �. � � ��fl � !. � r $ 11 +tw^nsr Y � ` ------ 'E'� �'`� � . � �� - - A + � . � � _: - ;_ � �0. �'`.i�'�t _ �"� � � I �'��=' .p �� 1:...'~ —�.,� � �f S��i ,k �\\ � �`��>. � � 4G} dM~ .. _--'.� ' '( � �E�AM st I t � � � !lltfMif �i1711�ff '� ' � �I `', E IItM 1f 1E 11�f1�0. '� o �sue � Legend i ��1 Hi�ligfioed Feature �n� � ' ( Cour�ty Bout�dary �oa+ I X MounWin Peaks Parcais Highways � l.akes and Large Rivers Streels f/ Stroama i H,�i„�, SAO Erosio� , (cont) 02015 D. R.STRONG Consulting Engineers Inc. Page 8 Level One Downstream Analysis Maertins Ranch City of Renton FIGURE 7. CITY OF RENTON LANDSLIDE HAZARD AREAS ; - _ , •�-_ __-; ; -- , _ , a - � - � , ��, :� __.__ � - � ,� - .��.� � _� � f � k � i � j... �a._._—,..,.��i �. 1 t i . �.._.._,_.....,..�.�_...ss.._._>_ g...��: I � �'�s 1 i g $ 1 � I� _ }! Slte ; ' � � � , , ; � ; , � � e. Y ��_.-- • - -- - -', Property " - City and County Bou�dary E �ther �..� •—+— t.� City of Rentan I'I Parcels li -' Sensitive Areas �ardslide � . VERY HI:.•H � HIGH �1023 0 51Z 1U23w s _: A-IODERA7E "�'�Y°{-'�'�� UN C LA59 f ED 02015 D. R.STRONG Consulting Engineers Inc. Page 9 Level One Downstream Analysis Maertins Ranch City of Renton FIGURE 8. CITY OF RENTON SEISMIC HAZARD AREAS �- ,.- - - � ,- �� - -- -- , --__ __- j a a __`� i � i ' �4t � � 1 � � 1 i i ._ ._ "___., _._J + � ` _.'' '__'' ' " i i S Ite ; ; , � � : . . ; ; � ; ; a � ; - _ _ _ : � E ---_ _ _ --- - - _ _ : , ; ; I-� Property �_ City and Cou�ty Boundary �.. + Other �.� City of Renton Parceis � `�-� Sensitive Areas "-" Fauiis 1029 0 512 1Q2�++� ! Seismi�Hazard�reas •ira`+�N.k.+rryrJ�4+�� - - 02015 D. R.STRONG Consulting Engineers Inc. : Level One Downstream Analysis Maertins Ranch C FIGURE 9. FEMA - FLOOD INSURANCE RATE MAP .��,. �,�� KiNG COUNTY :1'.Y Of PLNTON. . r�a� �la-cF. ti�. ' ' T": .;iME[' .- ( _ T- ,,, _� F ac= r_ U F 3 — TY OF RF.,NTON � 5f K�.TM s-Eeer 53U088 �� a :J Rer�aor� U NN Site � "'� uxn rtv sacas = �I 'E LiM1�S _ _ c _ \ _ o-� 1 Z� — ?-~ �— � ZIZ � P�'. ZONE X � � O ,� = I F > z < y' LEGEND ("" .�] �Pf(I'd fLUOU Mt�V_a.RU �1KCAti IhJni7.�ILU � � Ii� !Orl--Y6lR li(1C1U iONE A ...,.n,.•a•+rf,.s:�.��.,.a��-c�... ZONEAE i,�.�-�I,r�d..i.-..A.�n.d,�.rtn;ni.l ZONE AH .�+��kr.M.r 1 i.� t w�.r �w:.:ll�. ��• ��.�r:�.�;�: IMv I:.��v. .._,.i.... �L+��n�nA ZON[AO II,.v1,6Fsl�:� 1 i.. 1 k�i-u..�.. . .� J�y.r.G � -.�a� .�;�<M. � ;h..v nd.F�w .n�l^d�>JA ta�Il.;.if:n. .rk��Sk.al.��M1�m�m.l. ZONE A99 �• h� rc��*+�+� �.un ti��,R< r••.ai V�, 4�+4��t G:.vi �n.;Ar�t+a� �•tiM�m :r.4� .r�v�ielr.x�._ir:U�s�[-i�n�:Mn�n-ANrmro�:�!. ZONE Y �cot.d fl�.,d wel� .y.✓v iura.�l �.. , x11:r,�.w�4iw K�..I�ii�.unm.�Ganr.•�".1 ZONE VE �.�:.H�I d„�.1 ..nh .ci<in I.vanl ,.. � x1K Fara� I+ui ..rli.m �ii�rt+tir�1� I R<1ODbV4F.iREA�S I�l ZOkE A[ � OTHEK FLC�D AREAS ZONE X v..n�e u,�w it..d�e..- a rN��,r M1�wi r.ar.}a...ae drprlu+��A 1�,. � i �. „ ,,,n n•aa.�� . , ir�.:�. t aµr m,k•: xM Mpr��..,b�.l I� ' fe�m I.:�m IIK.-seJi ra.J. � 03HCN AREAS .... ZONE% .u,.�. ��e�m.�nM�.•tw 4_i:.h. ; n�...y�.��. ZONE D nr�v. � +at�.i:l� a....�f 1._a�;l, .� �.r�.3.,,�n n.. _.'S G. � STPCfJC; Cori=�_I''�n^ E�q'�ree"s Ir� Paa� 11 �.e O� � Uo � �r:;, , r,r: - , r^_=�_ i ��,: Ra�� C;t, :� P:r'�r FIGURE 10 USDA KING COUNTY SOILS SURVEY MAP � �� i . . � � � �.,,� �:� �� _� �,:.� ,�� „ , '_ ,,,F -�-- � .,.�..r. � �" ' � �� . �� .� � � � � . �' ;,�ta ,�:' ..�' �.,.�. - W . ... �S ',,..�vi..ea �� }� , 8 �_4� . �T�� ' �v� Ni:4'F•'�e '�'� � 7't:: y`�.. .:�' �"y.:,..��t '�f F Si.� }. � . � . '< .� � . 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" �S' . - d #x .'� a� - .. _ ��. 4�" . _.:� G - - � ��'' �`� �� W '��I ',T: �,��. �.. r �"� . ,� �'�� - � :-7�`� - t I -'a ` �•: "�;`��i�w� #�+ �: �, r� t<. 4'I� • �''�` 3 a „ t�<: ,3�� ' ' . ! k: , ,� � v. � ��,. ;+��'��' '�.� �# � e�;:' _ . s— � �► �� ,at �' �,r., � _ � � .-.�.w�ti� `� - `� � .... _ ��".,7 f�_ � � .'._ � � 3 � � ` �� . , ,..: � ,,= . � , � +� � � � �, �-�� - � � " ;,_,�.�-- r `_t y"; � a _ .'9'Sl� '- '"F - i,i�i ' f 1?N � S�'_��;. - �.." iT D'14 N 967090 Y.ilA 56::50 �S1S 56::10 56i,:J0 # # i f�YP5a1c1:1,18D/�onAptrtrat(SSx117f1�e. e g N 0 IS � 60 90 � A0 SD ]00 2m lOD �+.��,�� .�:� ��:u�,��,�,�. C2015 D. R.STRONG Consulting Engineers Inc. Page 12 Level One Downstream Analysis Maertins Ranch City of Renton AgC—Alderwood gravelly sandy loam,8 to 15 percent slopes Map Unit Setting • National map unit symbol:2t626 • Elevation:0 to 1,000 feet • Mean annual precipitation:20 to 60 inches • Mean annual air temperature:46 to 52 degrees F • Frost-free period: 160 to 240 days • Farmland classification:Farmland of statewide importance Map Unit Composition • Alderwood and similar soils:85 percent • Minor components:15 percent • Estimates are based on observations, descriptions, and transects of the map unit. Description of Alderwood Setting • Landform:Hills, ridges • Landform position(two-dimensional):Shoulder • Landform position(three-dimensionalJ:Nose slope, talf • Down-slope shape:Convex, linear • Across-slope shape:Convex • Parenf material:Glacial drift and/or glacial outwash over dense glaciomarine deposits Typical profile • A-0 to 7 inches:gravelly sandy loam • Bw1 - 7 to 21 inches:very gravelly sandy loam • Bw2-21 to 30 inches:very gravelly sandy loam • Bg-30 to 35 inches:very gravelly sandy loam • 2Cd1 -35 to 43 inches:very gravelly sandy loam • 2Cd2-43 to 59 inches:very gravelly sandy loam Properties and qualities • Slope:8 to 15 percent • Depth to restrictive feature:20 to 39 inches to densic material • Natura!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 storage in profi/e:Very low(about 2.7 inches) Interpretive groups • Land capability classification(irrigafed):None specified • Land capability classification (nonirngated):4s • Hydrologic SoiJ Group:B • Other vegetative classification:Limited Depth Soils (G002XN302WA), Limited Depth Soils(G002XS301 WA), � Limited Depth Soils(G002XF303WA) Minor Components • Everett I • Percent of map unit:5 percent � • Landform:Moraines, eskers, kames • Landform position(two-dimensiona!):Shoulder, summit • Landform position(three-dimensional):Nose slope • Down-slope shape:Convex • Across-slope shape:Convex • Other vegetafive classifrcation:Droughty Soils(G002XN402WA) , Indianola i 02015 D. R.STRONG Consulting Engineers Inc. Page 13 , Level One Downstream Analysis Maertins Ranch City of Renton , • Percent of map unit:5 percent • Landform:Hilislopes, kames,eskers,terraces • Landform position(fwo-dimensional):Backslope, summit • Landform position(fhree-dimensional):Side slope, crest, tread • Down-slope shape:Linear, convex • Across-slope shape:Linear,convex • Ecologrca! site:Thuja plicata-pseudotsuga menziesii/gaultheria shallon/polystichum munitum (F002XN903WA) • Other vegetative classification:Droughty Soils(G002XN402WA) Shalcar • Percent of map unit:3 percent • Landform:Depressions • Landform position (three-dimensional):Dip • Down-slope shape:Concave • Across-slope shape:Concave • Other vegetative classification:Wet Soils(G002XN102WA) Norma • Percent of map unit:2 percent • Landform:Depressions, drainageways • Landform position(three-dimensional):Dip • Down-slope shape:Concave, linear • Across-slope shape:Concave • Other vegetative classification:Wet Soils(G002XS101WA) ;�2015 D. R.STRONG Consulting Engineers Inc. Page 14 Level One Downstream Analysis Maertins Ranch City of Renton TASK 3 FIELD INSPECTION UPSTREAM TRIBUTARY AREA In evaluating the upstream area, we reviewed King County iMAP aerial topography, City of Renton Mapping Application and imagery and conducted field reconnaissance and have concluded that upstream tributary area for the Site is negligible. No runoff from the neighboring properties or streets appears to enter the property, therefore upstream tributary area is considered to be negligible. GENERAL ONSITE AND OFFSITE DRAINAGE DESCRIPTION There appears to be a highpoint on Site that bisects the Site into three drainage basins. However, upon further field inspection it appears that the high point is a consequence of prior Site grading to create buildings pads for the existing garage and barn on the Site. Therefore, for purposes of this analysis, the Site will be considered to be within one TDA with two natural discharge points, the north and east property lines (NDA 1 & NDA 2). Runoff will be conveyed to the north across NE 16�h Street and east across the east property line. Runoff from NDA 1 travels northeast as sheet flow northeast across the property over grass and pasture towards the northeast corner of the Site. From there a 12-inch diameter culvert corrugated plastic pipe (CPP) conveys water east towards a catch basin along the south side of NE 16t" Street. Runoff continues east towards a detention pond on the southeast corner of Lyons Place NE and NE 16'h Street. Runoff is conveyed east towards Lyons Avenue NE and then directed north to Greenes Creek and the associated wetland on the north side of NE 17t`' Street. Greenes Creek continues north approximately 0.75 miles until it converges with May Creek. May Creek eventually outlets to Lake Washington approximately 3.8 miles northwest of the Site. Runoff from NDA 2 will discharge into the existing drainage conveyance system located on the north side of NE 16�h Street. This path will converge with the downstream path for N DA 1 approximately 1,150 feet downstream of the Site. The downstream paths are further discussed in Task 4 of this report. G2015 D. R. STRONG Consulting Engineers Inc. Page 15 Level One Downstream Analysis Maertins Ranch City of Renton TASK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS DRAINAGE SYSTEM DESCRIPTION The downstream analysis is further illustrated and detailed in the Downstream Map and Downstream Tables located in Appendix A. The downstream area is located within the May Creek basin; more specifically the East Renton Plateau subbasin. The downstream area was evaluated by reviewing available resources, and by conducting a field reconnaissance on October 30, 2014 under rainy conditions. Downstream Path NDA 1 Runoff from NDA 1 currently leaves the Site across east property line travels across the adjacent property to the east and sheet flows into the collection and conveyance system located on the south side of NE 16th Street. The Site is situated with a 8-15% slope from southwest to northeast that allows runoff to be collected in the northeast corner of the Site and con�eyed into the existing conveyance system on the south side of NE 116th Street. Point "A1" is the natural discharge point of NDA 1. Runoff is conveyed northeast across the north property line as sheet flow and directed towards a corrugated plastic pipe inlet at the northeast corner of the Site (±0'). From Point "A1" to Point "B1", runoff heads northeast as sheet flow to a 12-inch diameter corrugated plastic pipe (CPP) (±0'-2'). Point "B1", corrugated plastic pipe inlet at the northeast corner of the Site (±2'). , From Point "B1" to Point "C1", runoff heads east as pipe flow via a 12-inch diameter � CPP (±2'-9'). Point "C1", runoff enters a Type 1 catch basin located on the south side of NE 16tn Street (±9'). From Point "C1" to Point "D1", runoff heads east as pipe flow via a 12-inch diameter CPP. No flow observed (±9'-172'). Point "D1", runoff enters a Type 1 catch basin on the south side of NE 16th Street (±172'). From Point "D1" to Point "E1", runoff heads east as pipe flow via a 15-inch CPP. No flow was observed (±172'-203'). Point "E1", runoff enters a detention pond at the corner of NE 16th Street and Lyons Place NE (±203'). From Point "E1" to Point "F1", runoff continues north as pipe flow via a 12-inch diameter corrugated metal pipe. No flow was observed (±203'-246'). Point "F1", runoff enters a Type 2 catch basin located in the northern portion of the detention pond (±246'). 02015 D. R.STRONG Consulting Engineers Inc. Page 16 Level One Downstream Analysis Maertins Ranch City of Renton From Point "F1" to Point "G1", runoff heads east as pipe flow via an 18-inch diameter corrugated metal pipe (CMP). Catch basin was inaccessible (±246'-300'). Point "G1", runoff enters a Type 2 catch basin located in the property immediately north of the detention pond (±300'). From Point "G1" to Point "H1", runoff heads east as pipe flow via an 18-inch diameter pipe. Catch basin was inaccessible (±300'-312'). Point "H1", runoff enters a Type 2 catch basin located in the property immediately north of the detention pond (±312'). From Point "H1" to Point "11", runoff heads east as pipe flow via an 18-inch diameter pipe. Catch basin was inaccessible (±312'-328'). Point "11", runoff enters a Type 2 catch basin located in the property immediately east of the detention pond (±328'). From Point "11" to Point "J1", runoff heads east as pipe flow via an 18-inch diameter pipe. Steady flow was observed (±328'-463'). Point "J1", runoff enters a Type 2 catch basin located in the middle of Lyons Avenue NE (±463'). From Point "J1" to Point "K1", runoff heads north as pipe flow via a 24-inch diameter CMP. Steady flow was observed (±463'-649'). Point "K1", runoff outlets to Greenes Creek and the associated wetland, approximately 38' north of NE 17th Street and Lyons Avenue NE (±649'). From Point "K1" to Point "L1", runoff heads north as channel flow through Greenes Creek. Flow was observed (±649'-978'). I Point "L1" convergence point with NDA 2 (±978'). � From Point "L1" to Point "M1", runoff heads north as channel flow through Greenes Creek. Flow was observed (±978'-1,324'). Point "M1", the downstream path reaches the quarter mile mark where the creek passes ' SE 105 Street (±1,324'). Greenes Creek continues north approximately 0.75 miles until it converges with May Creek. May Creek eventually outlets to Lake Washington approximately 3.8 miles northwest of the Site. I Downstream Path NDA 2 Runoff from NDA 2 currently travels northeast leaves the Site across north property line ', and sheet flows across NE 16th Street into the collection and conveyance system , located on the north side of NE 16th Street. i Point "AA1" is the natural discharge point of NDA 2 (±0'). i From Point "AA1" to Point "BB1", runoff will travel northeast as sheet flow to the flow line ' in NE 16th Street (±0'-34'). 02015 D. R.STRONG Consulting Engineers Inc. Page 17 Level One Downstream Analysis Maertins Ranch City of Renton From Point "BB1" to Point "CC1", heads east as channel flow via the curb line to an existing CB (±34'-91'). From Point "CC1" to Point "DD1", runoff heads east to a Type 1 catch basin as pipe flow via a 12-inch diameter LCPE (±91'-164'). From Point "DD1" to Point "EE1", runoff heads northeast to a Type 1 catch basin as pipe flow via a 12-inch diameter LCPE (±164'-208'). From Point "EE1" to Point "FF1", runoff heads northeast to a Type 1 catch basin as pipe flow via a 12-inch diameter LCPE (±208'-252'). From Point "FF1" to Point "GG1", runoff heads north to a Type 1 catch basin as pipe flow via a 12-inch diameter DI (±252'-317'). From Point "GG1" to Point "HH1", runoff heads east to a Type 1 catch basin as pipe flow via a 12-inch diameter (Type unknown) (±317'-348'). From Point "HH1" to Point "111", runoff heads north to a Type 1 catch basin s pipe flow via a 12-inch diameter (Type unknown) (±348-409'). From Point "111" to Point "JJ1", runoff heads east as to a Type 2 catch basin as pipe flow via a 12-inch diameter (Type unknown) (±409'-557'). From Point "JJ1" to Point "KK1", runoff heads northwest to a Type 2 catch basin as pipe flow via a 12-inch diameter (Type unknown) (±557-757'). From Point "KK1" to Point "LL1", runoff heads west as pipe flow via a 12-inch diameter (Type unknown) enters into an existing pond (±757-799'). From Point "LL1" to Point "MM1", runoff heads north as pond flow to pond outlet (±799- , 994'). I From Point "MM1" to Point "NN1", runoff heads northeast to a Type 2 catch basin as �� pipe flow via an18-inch diameter (Type unknown) (±994-1,016'). From Point "NN1" to Point "001", runoff heads northeast to a rock pad outlet as pipe flow via an 18-inch diameter (Type unknown) (±1016-1,076'). ', From Point "001" to Point "PP1°, runoff heads east over native vegetated flow path '�, enters Greenes Creek (±1076-1,150'). i Point "PP1" convergence point with NDA 2 (±1,150). ' From Point "PP1" to Point "QQ1", runoff heads north as channel flow through Greenes Creek. Flow was observed (±1,150'-1,320'). Point "QQ1", the downstream path reaches the quarter mile (±1,320'). Greenes Creek continues north approximately 0.78 miles until it converges with May Creek. May Creek � eventually outlets to Lake Washington approximately 3.8 miles northwest of the Site. The downstream path of NDA 2 converges with downstream path of NDA 1 approximately 1,150 feet downstream of the Site. Both of these flow paths combine within less than quarter mile downstream of the Site. 02015 D. R.STRONG Consulting Engineers Inc. Page 18 Level One Downstream Analysis Maertins Ranch 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 11 complaints within the last ten years. According to discussions with King County, drainage complaints along May Creek are not available because of the May Creek Drainage Improvement Project. Drainage complaints 2014-0152 and 2014- 0245 are not available because they were email inquiries about potential logging and a City of Renton project. Available drainage investigation reports attached in Appendix B. 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. , 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. �I i I 02015 D. R.STRONG Consulting Engineers Inc. Page 19 Level One Downstream Analysis Maertins Ranch City of Renton � APPENDICES �, � 02015 D. R.STRONG Consulting Engineers Inc. Page 20 Level One Downstream Analysis Maertins Ranch City of Renton APPENDIX A. OFFSITE ANALYSIS DRAINAGE SYSTEM TABLE 8� DOWNSTREAM MAP G2015 D. R.STRONG Consulting Engineers Inc. Page 21 Level One Downstream Analysis Maertins Ranch City of Renton FIGURE 11. DOWNSTREAM TABLE TDA 1, NDA 1 Basin: Ma Creek Subbasin Number: N/A Symbol Drainage Drainage Component Slope Distance Existing Potential Observations of field inspector Component Type, Description From site Problems Problems resource reviewer, or resident Name, and Size Dischar e Type: sheet flow, Constrictions, under capacity, ponding, tributary area, likelihood of problem, See map swale, Stream, drainage basin,vegetation,cover, °/o 1/4 mi=1,320 ft overtopping, flooding, habitat or organism overflow pathways, potential impacts. channel, pipe, depth,type of sensitive area,volume destruction, scouring, bank sloughing, Pond;Size:diameter sedimentation, incision, other erosion Surface area A1 NATURAL NORTHEAST PROPERTY CORNER t0' NONE NONE DISCHARGE POINT OBSERVED ANTICIPATED A1-61 NORTHEASTERLY NATIVE VEGETATION NONE NONE NO FLOW OBSERVED SHEET FLOW OBSERVED ANTICIPATED B1 PIPE INLET 12"0 CORRUGATED PLASTIC PIPE ±2' NONE NONE OBSERVED ANTICIPATED B1-C1 EASTERLY PIPE 12"0 CORRUGATED PLASTIC PIPE NONE NONE NO FLOW OBSERVED FLOW OBSERVED ANTICIPATED C1 CATCH BASIN -INLET(W) ±g' NONE NONE -OUTLET(E) OBSERVED ANTICIPATED C1-D1 EASTERLY PIPE 12"m CORRUGATED PLASTIC PIPE NONE NONE NO FLOW OBSERVED FLOW OBSERVED ANTICIPATED D1 CATCH BASIN -INLET(W) f172' NONE NONE -OUTLET(E) OBSERVED ANTICIPATED D1-E1 EASTERLY PIPE 15"0 CORRUGATED PLASTIC PIPE NONE NONE NO FLOW OBSERVED FLOW OBSERVED ANTICIPATED c>2015 D.R. STRONG Consulting Engineers Inc. Page 22 Level One Downstream Analysis Maertins Ranch City of Renton E1 DETENTION POND -INLET(W) ±203' NONE NONE -OUTLET(N) OBSERVED ANTICIPATED E1-F1 NORTERHLY PIPE 12"0 CMP NONE NONE NO FLOW OBSERVED FLOW OBSERVED ANTICIPATED F1 CATCH BASIN -INLET(S) ±246' NONE NONE -OUTLET(E) OBSERVED ANTICIPATED F1-G1 EASTERLY PIPE 18"�CMP NONE NONE INNACCESSIBLE FLOW OBSERVED ANTICIPATED G1 CATCH BASIN -INLET(W) ±300' NONE NONE -OUTLET(E) OBSERVED ANTICIPATED G1-H1 EASTERLY PIPE 18"p PIPE NONE NONE INNACCESSIBLE FLOW OBSERVED ANTICIPATED H1 CATCH BASIN -INLET(W) f312' NONE NONE -OUTLET(E) OBSERVED ANTICIPATED H1-11 EASTERLY PIPE 18"0 PIPE NONE NONE INNACCESSIBLE FLOW OBSERVED ANTICIPATED 11 CATCH BASIN -INLET(W) ±328' NONE NONE -OUTLET(E) OBSERVED ANTICIPATED 11-J1 EASTERLY PIPE 18"�PIPE NONE NONE FLOW OBSERVED FLOW OBSERVED ANTICIPATED J1 CATCH BASIN -INLET(W) ±463' NONE NONE -OUTLET(N) OBSERVED ANTICIPATED J1-K1 NORTHERLY PIPE 24"0 CMP 1649' NONE NONE FLOW OBSERVED FLOW OBSERVED ANTICIPATED C�2015 D. R. STRONG Consulting Engineers Inc. Page 23 Level One Downstream Analysis Maertins Ranch City of Renton K1 OUTLET TO 24"�CMP ±649' NONE NONE GREENES CREEK OBSERVED ANTICIPATED K1-L1 NORTHERLY GREENES CREEK AND WETLAND ±978' NONE NONE FLOW OBSERVED CHANNEL FLOW OBSERVED ANTICIPATED L1 CONVERGENCE GREENES CREEK ±978' NONE NONE FLOW OBSERVED POINT OBSERVED ANTICIPATED L1-M1 NORTHERLY GREENES CREEK lg7g' NONE NONE FLOW OBSERVED CHANNEL FLOW OBSERVED ANTICIPATED M1 END OF QUARTER GREENES CREEK +1,324' NONE NONE THE END OF THE QUARTER MILE MILE PATH OBSERVED ANTICIPATED DOWNSTREAM PATH IS WHE N THE CREEK CROSSES SE 105 STREET. THE CREEK CONTINUES FOR APPROXIMATELY 0.75 MILES UNTIL IT CONVERGES WITH MAY CREEK. MAY EVENTUALLY OUTLETS TO LAKE WASHINGTON APPROXIMATELY 3.8 MILES NORTHWEST OF THE SITE. �%2015 D. R. STRONG Consulting Engineers Inc Page 24 Level One Downstream Analysis Maertins Ranch City of Renton TDA 1, NDA 2 Basin: Ma Creek Subbasin Number: N/A Symbol Drainage Drainage Component Slope Distance Existing Potential Observations of field inspector Component Description From site Problems Problems resource reviewer, or resident Type, Name, Discharge and Size Type: sheet flow, Constrictions, under capacity, ponding, tributary area, likelihood of problem, See map swale, Stream, drainage basin,vegetation,cover, % 1/4 mi=1,320 ft overtopping,flooding, habitat or organism overflow pathways,potential impacts. channel, pipe, depth,type of sensitive area,volume destruction, scouring, bank sloughing, Pond;Size:diameter sedimentation,incision,other erosion Surface area AA1 NATURAL NEAR NORTHEAST PROPERTY t0' NONE NONE DISCHARGE POINT CORNER OBSERVED ANTICIPATED AA1-BB1 NORTHEASTERLY SHEET FLOW TO THE FLOW LINE +34' NONE NONE FLOW IN NE 16T"STREET OBSERVED ANTICIPATED 6B1-CC1 EASTERLY CHANNEL FLOW VIA CURB LINE TO _+_91' NONE NONE CHANNEL AN EXISTING CB OBSERVED ANTICIPATED SURFACE FLOW �, CC1-DD1 EASTERLY PIPE 12"0 LCPE PIPE +164' NONE NONE � FLOW OBSERVED ANTICIPATED DD1-EE1 NORTHEASTERLY 12"p LCPE PIPE 1208' NONE NONE PIPE FLOW OBSERVED ANTICIPATED EE1-FF1 NORTHEASTERLY 12"�LCPE PIPE f252' NONE NONE PIPE FLOW OBSERVED ANTICIPATED FF1-GG1 NORTHERLY PIPE 12"0 LCPE PIPE ±317' NONE NONE FLOW OBSERVED ANTICIPATED GG1-HH1 EASTERLY PIPE 12"0 (TYPE UNKNOWN) ±348' NONE NONE I' FLOW OBSERVED ANTICIPATED 02015 D.R.STRONG Consulting Engineers Inc. Page 25 Level One Downstream Analysis Maertins Ranch City of Renton HH1-111 NORTHERLY PIPE 12"0 (TYPE UNKNOWN) ±409' NONE NONE FLOW OBSERVED ANTICIPATED 111-JJ1 EASTERLY PIPE 12"0 (TYPE UNKNOWN) ±557' NONE NONE FLOW OBSERVED ANTICIPATED JJ1-KK1 NORTHWESTERLY 12"� (TYPE UNKNOWN) ±757' NONE NONE PIPE FLOW OBSERVED ANTICIPATED KK1-LL1 WESTERLY PIPE 12"q (TYPE UNKNOWN) ±7gg' NONE NONE FLOW OBSERVED ANTICIPATED LL1-MM1 NORTHERLY POND FLOW +994 NONE NONE POND FLOW/POND OBSERVED ANTICIPATED OUTLET MM1-NN1 NORTHEASTERLY 18"p (TYPE UNKNOWN) ±1,016 NONE NONE PIPE FLOW OBSERVED ANTICIPATED NN1-001 WESTERLY PIPE 18"0 (TYPE UNKNOWN) ±1,076 NONE NONE FLOW OBSERVED ANTICIPATED 001-PP1 EASTERLY VEGETATED FLOW PATH ±1,150 NONE NONE SURFACE FLOW OBSERVED ANTICIPATED PP1 CONVERGENCE GREENES CREEK t1,150 NONE NONE POINT OBSERVED ANTICIPATED PP1-QQI NORTHERLY GREENES CREEK ±1,320' NONE NONE CHANNEL FLOW OBSERVED ANTICIPATED QQ1 END OF QUARTER GREENES CREEK ±�,320 NONE NONE GREENES CREEK CONTINUES MILE PATH OBSERVED ANTICIPATED APPROXIMARTELY 0.78 MILES UNTIL IT CONVERGES WITH MAY CREEK. MAY CREEK EVENTUALLY OUTLETS TO LAKE WASHINGTON APPROXIMATELY 3.8 MILES NORTHWEST OF THE SITE. 02015 D.R.STRONG Consulting Engineers Inc. Page 26 Level One Downstream Analysis Maertins Ranch City of Renton FIGURE 12. DOWNSTREAM MAP ��-2015 D. R. STRONG Consulting Engineers Inc. Page 27 Level One Downstream Analysis Maertins Ranch City of Renton � w z � y � w � $ „ .� � .. ii � � N ._ _ _ - ___ _ . _ _._ ._- - _ __—-__.. _ _ . ._ _._ . .. ._-.__ _ _ _ _.____. . . _ _ _ _ ..._._ _ N .\�\\ � j � o _ -- - - - . , � � � Q - - ---- - -- - - �. � ,. . .--__------ - - � --- —� - -- - - ---- - . ._ . .. _ . _ Y � - ------ — ---- - -- - ... —�— — --- ------- — — — — � -- ------ - - : — — • �-- —� --- �-�' - -- - - - - - - - - ----- . . .. � � .._. - - - - — — - - - - - - - - - - - - _ _ ._ --- -- - , 148TH A SE- — — —\'\ \ _ _ _ _14$Tf-l_Al�'J�,IE_.__ .. � — — — — — ; �� .. _. . � � � . � ----- ------- - --__ ___ __ ------ ---- -- ----� _--- --�----� ---._- -- _--__ - - ----- " -_�__`_• � w a N � 1 . � W � ' � �� _ � , � o � o � _ � i � � \ } � � W � _ .. i � �� I \� . � �' � I �: � I � � �� , � i �� -' �-Q i .\��\ \�� •� i i z° , � �' '�� ------q--_---� \.\\ �\,� ` , �, I � . . ' o: . � : � .� $- ` �� , ,� � ; � , ; , . 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I � � � i I I i � I � /� �i' i N O RT H °R"`�°BY� �,'` D£SIGNED BY• GRAPHIC SCALE PROJECT ENGfNEER: MAJ 0 100 200 300 DATE: 1030.20f4 � � � PRO„L�CT NO.: 1410.3 1 INCH = 200 FT. „�,R£: �2 �. ,Rr�2T41�1 i4703'�3'�,D;an�;�gs�°iofs�Repar( Figures�3DSMAP74103.Cnj 7/E/2015 9'05:49 AM PDT COFYRIGI-�T�2�'4, D.R. ST�RONG CCNSULT VG ENGWEE4S INC. APPENDIX B. DRAINAGE INVESTIGATION REPORTS � \��'s ` .. ) � --- - . � Newcastle ` �4 a�:�ez�. � �` ME11f�10. �_.;�Y I ��-�� A Z — � �1ff29iMR � NEEIwCT I Z � 28T1!ST � y�+ � G `��„" Par��,#0323fi3�39�13 � � : � '�h'"�` Complaint�#�0�-0420 , �'�`�'�` ' , � �rrm a 3 "Fa.Mn a � �ur�si 3 razrusr �o� ,� �; arosnsr � NE2R�Sf �.:�a� +� - Parcel #5230Q0�22 ,� `, ��° �Complaint #?�006"=Q`�51 � � Y F �` ' �� ,E"�1`09-0250 & 201 t�-071# ?�° �r�n �� Ren��rce� #177�400� n � � � � Corf�'`� Ia��00�'s 008 �,�� 5 � � � 4 � � �� ,2014-0��& 2 14��1�=°t�'14� � R .�°r �r� � �, � s < �1t l� � q 4 aEr�s� �• g Y w�irrhsr � Q fla� ME�{(µ0. � j � � S � �F�lMn � Parcel #0323059274� � ` �� ., � � � Complaint # 2007-0223, � � - - - ,R 200$-01 G$$�--�8- �'�,�N��' �-�. ��nL�� e�. . - `— "'E-�-.. d >s sva�� s � as� e�- � � c+� s,e.. � _ �a .. 'ti �ur�sr .�' i i = � ii � � �vmar �i� 3 �iir+�sr � � .. - . � aE��zrnsr ff t�IfN R � 0 ]093R ��2015 D. R. STRONG Consuliing Engineers Inc. Page 28 Level One Downstream Analysis Maertins Ranch City of Renton Complaint # Parcel Summary Recurring Type Required number Mitigation 2007-0223 0323059274 Site materia� No N/A None storage issue. 2008-0168 0323059274 Property owner No N/A None to the north wanted to fence off pond; King County disapproved 2008-0342 0323059274 Special permit No N/A None inquiry. 2006-0451 5230000220 Pipe outlet No N/A None needed to be located 2009-0250; 5230000220 Flooding of Yes 1 Has not conveyance recurred since 2010-0714 system through 2010; 2010 property to complaint stream on west concluded the side of the issue was a property ditch maintenance issue and KC Roads put ditch on the maintenance � list. � 2004-0420 0323059038 Report No N/A None unavailable because of May Creek Project 2009-0008 1776400020 Flooding during No 3 None, not large rain recurring events on portion of property 2014-0152 1776400020 Logging inquiry No N/A None 2014-0245 1776400020 Project inquiry No N/A None ::2015 D. R.STRONG Consufting Engineers Inc. Page 29 Level One Downstream Analysis Maertins Ranch City of Renton FILE NO.: 2007-0223 � K I N G CO U N TY of Com 10731 148T"Ave.SE!#14515 SE 107"{PL.Renton DEPARTMENT OF NATURAL RESOURCES ADDRESS: p• AND PARK NannE: Virgi Pacampara WATER AND LAND RESOURCES (206) 296-8398 PHON E: DRAINAGE INVESTIGATION REPORT DATE OF INVESTIGATION: March 23, 2007 FIELD INVESTIGATION INVESTIGATED BY:Virgil Pacampara During the annual inspection of facility D91403 (SP #0584163-64). I noticed that a section of the northeast side of the tract were being used as storage area for construction materials, staging area. The construction materiais were blocking access to CS/CB-1. I also noticed slurries south of Lot northeast of CS/CB-1. The open portion of the Lot appeared to be the mixing/cleaning area for masonry equipments/tools. Some contaminated water appeared to be flowing towards the pond but disappeared before it reached the slope. I spoke to the Mr. Kannon (lead person of Murray Franklyn, the sub-contractor stationed near the facility) about the materials around CS/CB-1, and within the northeast side of the tract, and possible water quality problem due to presence of slurries. I also spoke to him about extending the existing silt fence towards the east corner of the properiy to protect the pond from possible contamination during construction. I spoke to Mr. Curtis project manager of KBS Development He informed me that during the construction, they draw away some of the run-off flowing towards the existing pond into the drainage system of the new development. They replaced also the open channel/ditch that conveyed water towards the west side of the pond with 12-inch drainpipe and installed type-1 catch basin to collect the water from west side corner outside of the tract. He also said that drainage inspector from City of Renton was Patrick Miller. I returned to the site on 3/29/2007. The subcontractor (Murray Franklyn) has not addressed the possible water quality problem (removal of construction materials around CS/CB-1 and within the tract, and extension of the silt fence towards east side). REFER TO FACILITY SKETCH — . K I 11 C�U 1'lt 2008-0168 a g Y FILE NO.: � Department of Natural Resources and ADDRESS: #1608 Lyons Place NE Parks Debbie Saki NAME: Water and Land Resources Di�ision �425) 387-6466 PHONE: DRAINAGE INVESTIGATION REPORT DATE OF INVESTIGATION: 3/26/2008 FIELD INVESTIGATION INVESTIGATED BY:Virgil Pacampara I wentto the site on 3/26/2008 and investigated a drainage complaint.The complainLs of Mrs.Debbie Saki was about facility D91403. She thinks that she has done her part of watching the facility,and making sure kids and neighborswill notvandalized it She wants fence around I the facility for Uie following reason: I 1.That neighbors were using the facility as dumping area. ' 2.That kids in the neighborhoods were entering and playing in the facility. 3.Thatthe chain on the bdlards are on ground and the lock was on there. 4.Thatadjacent neighbors were entering through the facility to get to other places. 5.Mrs.Saki wanLs to know if what are their options if they(Homeowners association)want to build a fence. Mrs.Saki's thoughts that the facility should be maintained by City of Renton and it was recently annexed to the City of Renton. I noticed litter on the pond butstill on maintienance standard.During the investigation,I re-adjusbed tlie chain and the padlock,and installed it to the two removable bollards.The approved plan of the pond indicabed a slope of 1:3 on inner side slope,and it dces not require a perimetier fence.Records indicated that the facility pond is still within FGng County jurisdictan and have not been annexed to City of Renton.The KCSP 0584163-164 were the only remaining short lats th twas not annexed by City of Renton in the area : � � . � �� o Lo-t-19 � I Lo-t-18 � ,� u a I �B o � °c_'�� O Y � • • — • • — • • CityofRento�Jurisdiction ' .._.._.._.._.._.._.._.._.._.._..—..— r...,...�....,�.. -�F ��x�E-�--�X�F � � C&5 z 3 I CB-Z 46'.�7„pV � CB„4 � 1.5'deep ditch BY 10'wide svsle � 1:35�Op s�a.�P �..�.. � �. . r I L �N. � � � � O �� e55 . a+ � � �e� � Saki �' � � House � #1608 � ��`�`~�,�'�e\P a� Z LLI � �n' � yo� � a ti' Z � � CS/ 1 50'- " �� F-+ � o R � w Q I 7 ?� � � �i � � s�°A � W � � � Easement � ♦v P . \ .�p � A .._.._.._. ._.._.._..: Z� LYONS PL.SE. 1 s�o,6 '�' � P � �� O R �,a � � S�P"f 6. � ��P �� 1: Slope � t.! \ .351ope � � g� � C&3 �; r a ' j ..�.._.._..—..�_.___;.____�y.,-r... 0 20'UtiityEasement 1.5 deepditrh Z .._.._.._.._.._.._.._.._..—.._.._. H � n N �, .� _ m o ° � � � a � � 3 �i O � NTS � � C � N O -� U � � O C � Y - - -- ----- -- ----- - -- - --- -- --� Complaint 2006-0451 Desi Lazaro (King County Roads) Investigated by Andrew McDonald on June 20,2006 I visited the site and took photos of the cross culvert pipe running from east to west beginning at the eastern ditch of 147th AVE SE and running beneath tl�e road«ray emptying into a 22" x 52" catch basin. This twelve-inch concrete pipe cross culvert enters into the eastern wall of the catch basin and a six-inch flexible pipe outlets from the western v�Tall of the catch basin. This catch basin (and presumably the pipe) sit v��ithin a ten-foot wide drainage easement that is shown on the plat as five feet either side of the property line separating tax parcels 523000-0220 and 523000- 0210. I followed the six-inch pipe dov�n to the stream in the rear of the residence at 10269 147tn AVE SE (after knocking on the front door) and but could not locate the pipe end as I assumed it would sit beneath the property line or near therein. W � � � Ditch ....,.' ........................................................ a � � pproximate � ' location of . �� stream bed � � � 1 � . ' Catch basin ! L._._._._._.-.-._.-.-._._._._._._._._._._._ ._._. • •��1��• •�• �� 4� .. .... . ..... .. . . . r Six inch flexible pipe(presumed location) 3 � Twelv.-inch CP f I � � f ' ; I � 10269 : 1 t . � I � I .....1.................................................... : I I - � I February 20, 2009 TO: File 2009-02�0 FM: Brian Slei�ht RE: Morse Ensineerin�Revie�-��2009-OZ>0 BACKGROUND Pegi Morse has had �a�ater o��erflo��from the conveyance system on her property several times over the past i 10 or so years. 7 he water flows do��n her�ravel drivewa�- causin�erosion and flo«-s into and around her I earage at the bottom of the driveway. I FINDINGS The conveyance pipe through Ms. Morse's property starts out as a six or eiRht inch pipe in a catch basin �I near 147`�Avenue Southeast and discharges into the stream behind her house via a four inch black flexible I pipe(Photo 1). The location and condition ofthis pipe is unknown. It appears to pass underneath several ' large trees and shrubs and there is apparently a transition to the four inch pipe without a structure. Many ! years ago while investigating this a similar problem at this same site,the outlet of the pipe could not be , found and the problem��as attributed to the assumption that the outlet�vas obstructed. , DISCUSSION The two options available are to construc[a new conveyance system through Ms. Morse's property or protect the overflow path so it does not damage the property. Building a new conveyance system��ould require the conveyance line to go around the south side of the house. It would not be practical to cut down the large trees along the driveway and remove the stumps to put the system back where it apparently is right now. It would also be difficult to construct a conveyance system dowm the driveway and around the garage as there is very little room beriveen the gara�e and the property line and there is not enough room between the house and garage to use heavy equipment. A conveyance system around the house��•ould be approximately 220 feet and require a catch basin at the angle point. Permits would be required to construct a ne��outfall into the stream and thre may be utility conflicts between the house and the roadway. Protecting the overflo��path would involve paving the area around the overflowing structure and the driveway down to the garage. Provisions�vould be made to direct the�vater to the north side of the garage ��here the overflo��ing��ater Qenerally ends up no«�. RECOMMENDATIONS 1 recommend this be turned to an NDA Quick Fix to pave the driveway. June 8,2009 update: 1 met Ms. Morse today at her house to describe the project to her and have her sign a tce. After�ve went over the project, she siened the tce in my presence. The one change we talked about was trying to save the rhododendrons just do��nstream of the overflowing structure. I told her we would fill in the south side of the structure and curve the pavement around the uphill side of the rhododendron. � � ° 3 � ¢ Wo z � W w o � � p � � H F- H w 3 �, a., 2 ¢ v � z ¢ � � Q � Zw � xW Z � Ww � � wx a I pQ � U �'" � O � � � � w . 00 ¢ �" Z � Fx-� ,� wwZ � w O � w r� c7 O ,� 3 "' w rx . �• w O o ¢ wz .� 3x � � � . '� o3x �, p � Ww � Q �" � 3 ° � c�73 � `^ � ¢3w ° � ° � oz ° � c � xz ° � � � a�, � 0 ,..��. 0 �' w O � � w � wQa Op � � w � ? w a �lOUzcG aQQOc�nH ,z � a � QtiO � � � ; P S¢�� ,,. 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N J� W. !� yF � A N Y �M` d�d'Y�°� "°'f � �^f'� ' e + ++'�� ` .�r' : ��°�o � F+ ,4 7 ��'�Y i" ' �p r��' f,y .1�i F w.6+at +"J i y�p'� � S�"� �`' ' ,..� .. ,�i� �;�y��y . ' ^�+y� 4 x;, S �.. �+5 , �+��+r .�d"� Qrr �`� . !,,v � '� �.. .�y s�r .�' M1�.�4� +a�� gr-�'4�. � �4t {��y ` d e�,�, , �;'- "' :�i��P '°��`,r .re °* �� ,��4 �� it, Ay� �, �� ,v t y r� v�� C?�; ` � '' ' � ,� , � a . � ,� �� d0� �. ��,�f ti� , � "�p ' � � � a n��,�;'�M �;� 4 � '+3 �' � "�,� � ,.'�,� �yM t'�"��:'�a�dr� w�� ` �� ,, �aP�, �� t� ' "� '��y� a �`��"�, �y �, �� ' � �� ' � ��: . y� ��., ., . � � � ,� ��, ,r x-, , �*��.�� x , �;� ��A� �� :; .: ;: , ; � . � �s . � ;�. � "V �r' �'. � i �rf, ` 7 � -: . e , � �,a � / �.: v�'� � eo, ma s� , !��, �4r � .�am� .W.� .W,!..;.�''� _ � .!� 'L Y7 ....t� .,..._...�C.. .. ..., , .'�� . ,.....�. . �a _ v.. March 28, 2011 TO: File 2010-0714 FM: Chris Gallagher BACKGROUND Ms. Pegi Morse owns a single family residential property at 10269 147th Avenue Southeast. A 12" concrete culvert in 147th Avenue Southeast conveys water westerly and discharges onto Ms. Morse's property at a catch basin near the property line. Ms. Morse has a private conveyance pipe on her property. Her system consists of a 6" pipe coming out of the catch basin and discharging to the creek in a 4" pipe. It is unclear how the connection between 6" and 4" pipe on Ms. Morse's property was constructed, or its current condition. Ms. Morse has experienced a surcharge from the catch basin near her property line numerous times, resulting in erosion of her driveway and water in her garage. This has also been investigated under file 2009-0250. As a result of file 2009-0250,a Neighborhood Drainage Assistance (NDA) project was constructed on Ms. Morse's property. The NDA project was constructed to protect the overflow path, and consisted of paving the driveway (see Photo 6) and installing a strip drain near the garage door to direct water to the north side of the garage (see Photo 1). INVESTIGATION I met Ms. Morse at her property on February 18, 2011. She told me that when water overflowed from the catch basin on her property(see Photo 5), it was like a river flowing down her driveway. The strip drain at her garage was unable to collect all of the water and water flowed up against her garage. According to Ms. Morse, water reached a depth of at least 1 foot at her garage door. Some water was able to seep through the garage door and into her garage. I investigated the upstream system. A culvert in 148`h Avenue Southeast conveys water from a roadside ditch along the eastside of the road westerly. The water is then conveyed westerly through private property before reaching 147th Avenue Southeast. Water enters the eastern roadside ditch of 147`n Avenue Southeast approximately 550 feet north of Ms. Morse's property. It is not clear how much water is supposed to flow north and south from the point where water enters the ditch along 147`n Avenue Southeast. However, alluvial deposition in the roadside ditch of 147th Avenue Southeast appears to result in some of the water coming from 148`h Avenue Southeast being conveyed southward in 147`h Avenue Southeast and to Ms. Morse's property. DISCUSSION I spoke with Will Fogelberg, King County Roads Division Two Maintenance Supervisor, on February 25, 2011 regarding drainage in this area. I told Mr. Fogelberg of the deposition in the roadside ditch. I asked Mr. Fogelberg to put the 147`h Avenue Southeast ditch on his maintenance list. Subsequently, I called Ms. Morse on March 2, 2011 and informed her that I have contacted King County Roads, informed them of the situation, and had them place 147"'Avenue Southeast on their maintenance list. Ms. Morse says she is receiving more water than she used to. Alluvial deposits are impacting which way water flows when it gets to 147`h Avenue Southeast. This could account for her statement. RECOMMENDATION I recommend that this file be closed as a referral to King County Roads. � : �, Y.� ' ��.1y, "�:':,,z.�.R ��_� .' �: } '€:- - � ` �� `:, > . : " 3 E _i,�4 �S� '�tJli�r:f` - -x� - t * �`� 4 - �: �� '• � • �`../ . `Y� � '�� • � . +G �'" � • •' .` � ° �,: �� ' � � _ k f� t.f�,� .y � �`��. ' '.� ,��1 '�.'.`,. '#�y� .� _��r - .. - �a. .. .- — y�--. . �� . �.,._ "' � �-.. - �' . { a � ; �.s�r,� ��°" Y �.�� _.#�r. ■� ■r��y . { r �1�a �` I i. -� ~,.�. �#,.- e:. ,',y . •��_1# r-- a . ■ :.,�, =a rf •*�, ,�� - ,�� _:'�a•��'•r � ,y. �€ � � � ,,3 ..b�. ,• �....' , -. , , � " � .. ':'� ir'� I * y"�'�� d_._ 9� - +f ,s� .. • °�'�... _ . a k - - - 'ee w-: '�I il �� , �� s' _ s�-;'. � � - _ � ��, � � _�� 'Yf'�.: •, ' t t �.� _ l. / � • - a -�� - - .-'� -..y�_ :t..� . � i � � 4 S�'�a * �fe. .''� � . � .:.- . . - ' r' .1 i � #.*, �� f Y .z �'i�. <u r � ..� . t #.. �� " � . ' ;�3� � �3�-p. 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' � x +-� � I • ��. { � � �� "ti�� I�'� :�" � ' � , ,�17� ` ��/�, �jK � , . v, � ^ 4 c�= ,�a a t� � , a � _yy. ' s / � �.��"' :�•. ..,..; 1{,y.. ' M,.. Yt�'„ , .al... � .�,. . �V, uuir .. �I � . KING COUNTY WATER AND LAND RESOURCES DIVISIOI�' DRAlNAGE INVESTIGATlQN REPORT INV�S7IGATION REQUEST 'Ros�Ern: ' FLOODING Type ';i R I� RECEIVED BY: BS/Wkp Date: 01/05/09 OK'd by: File No 2�09�04�8 �E�� ro 'a ema[� :r- 3BS- _ _-�=�'-��F�. � ��._�w..�,. �_��= .��-��.��..�_: �NAME: CLAUdlA DONNELLY P�oNE : Other: Address: '[0415 147 AVE SE City RENTON State _ Zip 98059 � +ca�io o ��o ,e: 'fi ��ff � � _ - � �:.��:�Y� - - _ . .��.�--��u�-:. Access Permission Granted II F' C� 1�St Would Like To Be Called and or Pr sen ❑ ( / e t} � REl�fARKS: A portion of the donnelly property floods during large rain events. Plat name: COTTOM GLEN Lot No: 2 Block No: Other agencies involved: No field investigation required ❑ � . . #�;��, A._P�.�'E�D� -. �4.�2 � R�lM�:.�;._ � _ ��._,�___ .;�. � „ .�,,s�- — � — ..._.. ... . . _ . u. �. — 1� SE S 3 T 23 R 5 Parcel # 1776400020 Kroll: 800E TBros: 626J5-J6 � MD 1 � 3 4 Basin MAY Council Dist 9 Charge #: �.� - __ RESP014'SE'_• -.-..t..�, �r� T ._ . _ . �.__ . . .. .. .,�..r-;as;. . r.l�f� Citizen notif ed on ❑ phone ❑ letter ❑ in person ❑ email f3.(2�1��i —.�ts oP,Y,��cc� rf v.� T-f� tia� uli, Td�/�zoG�r.f-.� �f �udKc-�7�.r ,�o� f��.�De'�'. �l Do.�-�'�G�� S cv.�.t�.✓rCY -v�9� �'t� �o.� oF �� i_�ST /�'p t�f�l /� G r�o0 Gff��+'Cci T ��L��/,GocfO !� %�� itD6��'/ ! ✓�'J�O . � �. ,DXs�Qs�7�`zo�� :� �..:�m-� ' OR: No further action Turned to: on by recommended because: ❑ Lead agency has been notified: ❑ Problem has been corrected. ONo problem has been ❑Prior investigation identified. addresses problem: SE�FrLE# ] Yrivate problem-NDAP will not consider because: ❑ Water originates onsite and/or on neighboring parcel. ❑ Location is outside WLRD Service Area. ❑Other{Specify): c�.`��-��'��Vi�..��3'J�� 1 2` Z( �� :�:r .. rF.r! 6 \J SECTION IV FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 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 Till Forest 177,683 s.f. 4.079 acres �,2015 D. R.STRONG Consulting En ineers Inc. Maertins Ranch Page 14 ' 9 Technical Information Report City of Renton PRE-DEVELOPED HOURLY TIME STEP MODELING INPUT: Land cover Entire Site Till forest(ac) 4.08 Till Grass(ac) 0.00 Wetland (ac) 0.00 Impervious(ac) 0.00 Scale Factor: 0.85 Time Step: Hourly Data Type: Reduced Project location: Landsburg Total Area: 4.08 PRE-DEVELOPED HOURLY TIME STEP MODELING OUTPUT: Flow Frequency Analysis Time Series File:predev.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.319 2 2/09/Ol 18:00 0.378 1 100. 00 0. 9�0 0.052 7 1/05/02 16:00 0.319 2 25. 00 0. °�C; 0.203 4 2/28/03 16:00 0.260 3 10. 00 0. 9C�; 0.036 8 3/03/04 2:00 0.203 4 5. 00 0.8C 0. 186 5 1/05/05 10:00 0. 186 5 3. 00 0. 6�:"' 0.150 6 1/18/06 21:00 0. 150 6 2. 00 0.5: 0.260 3 11/24/06 5:00 0.052 7 1.30 0.2_ : 0 . 378 1 1/C°/08 7 : 00 0. 036 8 1. 10 0. 0` � ; , _ � _. .. . . _ _ - . . �.. _� �.. �� .I f...�." �,,. .,._�. � L �� -__ ., .� _ I..._:.,�. ._ .... � � _ __ � Technica�Information Report City of Renton FIGURE 5 PREDEVELOPMENT AREA MAP ��2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 16 li Technical Information Report City of Renton ii I � � � . � . . . i. . .-�-- . 1- . ____�_ _. � -- - -� _ N� �srH sr W z I o �— (� C� �u � N . • � 2 2 � 3 ^ � j N 2 h � � � P I I � Z W p � • - O U 2 �C " . � � $ d 2 � I _ �V/�J � e 1p I — " 2 � O . ' _ O o I W m � � I I I � — l � 1 � �\ \ .� . � . � � -9�,\ JI �-., _ \ y` � _ � � \ FZ — Q � � , LEGEND Q I TILL FOREST• 177,683 S.F. W Z � � W O \ = 2ti . I \ / TOTAL AREA: 177,683 S_F. ' � Z � Z . I. -1 ; ' � � ° e `� � � � Q � � � i � � � z , \ � o Q � o � � � Z \ � ' � � � �. � w ' \ � i W �. . � �, I I � � �. � -��.� �Z I I _ \ � I y\ I .\ ``�� I . QG\ �y � � \ �'o � � � � I � \ � NORTH DRAF7ED BY.� L�7J I ' GRAPHIC SCALE DES7CNE0 BY.• I Q 40 80 '�'ZO � PftOJECT£NGINE£R.• 1lAJ \ \ \ - � DATE': 11.05.2014 I � PROJECT NO.: 14103 . � I 1 I N H = FT. C 80 �rcuRE: s R:�20i4�1�74173�3�Qrowmgs\Pbts�Repo�t Frgur=s\3r�REDE✓14)03.d.vg 7/6/2015 11:G2:09 AM PD7 CGPYR�-iT Q 2014, D.R. STRON3 CONSULTING ENGI��ERS INC. � i 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 vault were modeled as "Till Grass" and Impervious as appropriate. Results of the KCRTS analysis are included in this section. Area Breakdown I Developed *ROW 43,065 0.99 Impervious 41,603 0.96 Pervious 1,462 0.03 �'I Lots/CDS Easement 124,122 2.85 i Impervious 55,562 1.28 Pervious 68,560 1.57 *Tract A 10,496 0.24 Impervious 3,674 0.08 Pervious 6,822 0.16 *includes bypass area , Impervious 900 0.02 Pervious 2,200 0.05 02015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 17 Technical Information Report City of Renton DEVELOPED HOURLY TIME STEP MODELING INPUT: Land cover Entire Site Till forest(ac) 0.00 Till Grass(ac) 1.71 Wetland (ac) 0.00 Impervious(ac) 2.30 Scale Factor: 0.85 Time Step: Hourly Data Type: Reduced Project location: Landsburg Total Area: 4.01 DEVELOPED HOURLY TIME STEP MODELING OUTPUT: Flow Frequency Analysis Time Series File:rdin.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak — — Peaks — — Rank Return Prob (CFS) (CFS) Period 0.849 4 2/09/Ol 2:00 1.55 1 100. 00 0. 990 0.502 8 12/03/O1 17:00 1.03 2 25. 00 0 . 960 0.844 5 9/10/03 15:00 0. 982 3 10.00 0 . 900 0. 982 3 8/26/04 1:00 0.849 4 5. 00 0 . 800 0.808 7 10/28/04 18:00 0.844 5 3. 00 0. 667 0. 838 6 10/22/05 17:00 0.838 6 2. 00 0.500 1. 03 2 11/21/06 9:00 0.808 7 1.30 0.231 1. 55 1 1/09/08 7:00 0.502 8 1. 10 0 .091 Computed Peaks 1. 37 50. 00 0 . 980 ��2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 18 Technical Information Report City of Renton BYPASS HOURLY TIME STEP MODELING INPUT: Land cover Entire Site Till forest(ac) 0.00 Till Grass(ac) 0.05 Wetland (ac) 0.00 Impervious(ac) 0.02 Scale Factor: 0.85 Time Step: Hourly Data Type: Reduced Project location: Landsburg Total Area: 0.07 BYPASS HOURLY TIME STEP MODELING OUTPUT: Flow Frequency Analysis Time Series File:bypass.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.012 3 2/09/Ol 2:00 0. 024 1 100.00 0. 990 0.005 8 12/03/Ol 17:00 0. 015 2 25.00 0. 960 0.009 7 9/10/03 15:00 0.012 3 10.00 0. 900 0.012 4 8/26/04 1:00 0.012 4 5. 00 0.800 0.010 6 10/28/04 18:00 0. 010 5 3.00 0. 657 0.010 5 10/22/05 17:00 0. 010 6 2.00 0.500 0.015 2 11/21/06 9:00 0.009 7 1.30 0.231 0. 024 1 1/09/08 7:00 0. 005 8 1. 10 0. 091 Computed Feaks �. G21 50. 00 O. G80 �`i2015 D. R.STRONG Consulting Enaineers Inc. Maertins Ranch Page 19 Technical Information Report City of Renton FIGURE 6 POST DEVELOPMENT AREA MAP _� _, � ,. ��;��.� .,� ,�_,„ ��,� _� _ �, . ��,,..��, � ,.�, �,� , �.y� � _ Technical Information Report City of Rentor — � \ . ' � � I ' ' ` I • � . �_ , � W , --� I 2 C� NE 1fFH-s�i — 2 � o ' W �i � N I � � ---- ---_— ------ 2 2 � N ^ -- --- � � 3 �— ' ' • �� ..'. —`�f � ./��. . ... .�. :.. �� _ � j h � � r � � ' � . . ....-.-.- . � Z W C 4 I O U I � 900 SF OF � o g i � . � l ; IMPER l/IOUS n � � Q � r I i I BYPASS AREA U 1� i � o � I I 2,200 SF OF � � I J w m I O { �: � I BYPASS AREA � � � �.... ..� � I I m � z � � � ; ( ml , I . � � � �� ti � ►� , � � . . _J .� \ \. ' � , ` � . � ' � i Q I \ ' J � � t � II , � \ � , � LEGEND 'Q1, � � � W � RIGHT OF WAY AREA*: 43,065 S.F. � � � �. IMPER 1/IOUS AREA: 41,603 S.F. � Q = Z � P R E V10US AREA: 1 462 S.F. U (� , � W � z � � z / � � LOT AREA/CDS EASEMENT.• 124,122 S.F. � � Q = � I lMPER UJOUS AREA: 55,562 S.F. � � fn � Q � � ! PER UIOUS AREA: 68,560 S.F. � � � � . I I , TRACT 'A" AREA*: 10,496 S.F. � W � O / I IMPER 1/IOUS AREA: 3,674 S.F. � � � p Z \ / P E R V I O U S A R E A: 6,8 2 2 S.F. � � W ` / I _ I O � \ \\/ 1 TO TAL AREA: 177,683 S.F. � ' I *INCLUDES B1PASS AREA ~ � � \ / I I O ; I � � \. , \./ 1 — � , � �. ��o�. � � z _ , , �� . �Q . , \ G I / — _ �Z � . \ �o I � N O RT H ORAF7E0 BY.� (,�lY � I - � GRAPHIC SCALE DfSIGNED BY.- PRO,JEC7 ENClNfER: MA✓ m \ I ' �I =- � $�O DA7f.� 11.OS.201f � � PROJECT NO.: 14f03 � • � �` l' 1 INCH = 80 FT. F/GlIRE B R:�7074'�717q103\3\fi•awrngstiPlots�Repo�t F��ures\3DEV74703.dwg 7/E/2015 77:07:37 AM POT CCPYR�97�2G'4, D_R. STRONG CGNSULTING ENG NE=RS INC. PERFORMANCE STANDARDS (PART C) The Project is required to adhere to Level 2 Flow Control criteria. The Level 2 performance criteria 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 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 100-year peak flow. FLOW CONTROL SYSTEM (PART D) The Site will utilize a detention vault 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 project must analyze the feasibility of infiltration and dispersion of roof runoff. The project will utilize splash blocks to disperse 1,400 s.f. of roof area per lot with the maximum of 700 s.f. per one splash block. ,�'2015 D. R STRONG Consulting Engineers Inc Maertins Ranch Page 21 Technical Information Report City of Renton FLOW CONTROL FACILITY DESIGN OUTPUT Retention/Detention Faci_--�1 Type of Facility: Detention Vault Facility Length: 74 .50 ft Facility Width: 75.00 ft � Facility Area: 5588. sq. ft Effective Storage Depth: 9. 00 ft Stage 0 Elevation: 445. 00 ft Storage Volume: 50288. cu. ft Riser Head: 9. 00 ft Riser Diameter: 18 . 00 irches Number of orifices: 3 �ull Head Pine Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1. 10 0. 098 2 5.00 1 .20 0. 078 4 .0 3 6.25 1 . 00 0 . 045 4 . 0 Top Notch Weir: None Outflow Rating Curve: No�e I Stage Elevation Storage Discharge Percoiaticn (ft) {ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 445.00 0. 0.000 0.000 0. 00 0. 01 445.01 56. 0. 001 0.004 0.00 0.02 445.02 112. 0.003 0. 005 0.00 0. 03 445.03 168. 0.004 0.006 0.00 0. 05 445.05 279. 0.006 0.007 0. 00 0.06 445.06 335. 0. 008 0.008 0.00 0. 07 445.07 391. 0.009 0.009 0. 00 0.08 445.08 447. 0.010 0.009 0. 00 0.09 445.09 503. 0. 012 0.010 0. 00 0.27 445.27 1509. 0. 035 0.017 0.00 0.44 445.44 2459. 0.056 0.022 0.00 0. 62 945. 62 3464 . 0. 080 0.026 O. 00 0.80 445.80 4470. 0. 103 0. 029 0.00 ', 0. 97 445. 97 5420. 0. 124 0.032 0. 00 1. 15 446. 15 6426. 0. 148 0.035 0. 00 1. 33 446.33 7431. 0. 171 0.038 0. 00 1.50 446.50 8381. 0. 192 0.040 0.00 1. 68 446.68 9387 . 0.215 0. 043 0.00 1.86 446.86 10393. 0.239 0. 045 0.00 2.03 447.03 11343. 0.260 0.047 0.00 2 .21 447.21 12348. 0.283 0.049 0.00 2 . 39 447 .39 13354. 0. 307 0.051 O.00 2.56 447 .56 14304. 0.328 0.053 0.00 2.74 447.74 15310. 0.351 0. 054 0. 00 2. 92 447. 92 16316. 0.375 0.056 0.00 ��2015 D. R. STRONG Consulting Engineers Inc. Maertins Ranch Page 22 Technical Information Report City of Renton 3. 09 448.09 17265. 0. 396 0 . 058 0. 00 3.27 448.27 18271. 0. 419 0 . 059 0. 00 3. 44 448.44 19221. 0. 441 0.061 0.00 3. 62 448.62 20227. 0. 464 0.062 0.00 3.80 448.80 21233. 0. 487 0.064 0.00 3. 97 448.97 22182. 0.509 0.065 0. 00 4 . 15 449.15 23188. 0.532 0.067 0. 00 4 .33 449.33 24194. 0. 555 0.068 0. 00 4 .50 449.50 25144. 0. 577 0.070 0. 00 4. 68 449.68 26150. 0. 600 0.071 0. 00 4.86 449.86 27155. 0. 623 0.072 0.00 5.00 450.00 27938. 0. 641 0.073 0. 00 5. 01 950.01 27993. 0. 643 0.074 0.00 5.02 450.02 28049. 0. 644 0.075 0.00 5.04 450.04 28161. 0. 646 0.076 0.00 5.05 450.05 28217. 0. 648 0.078 0.00 5.06 450.06 28273. 0. 649 0.081 0.00 5.07 450.07 28329. 0. 650 0.085 0.00 5.09 450. 09 28440. 0. 653 0.086 0.00 5. 10 450. 10 28496. 0. 654 0.086 0.00 5. 11 450.11 28552 . 0. 655 0.087 0.00 5.29 450.29 29558 . 0. 679 0.096 0.00 5. 47 450.47 30564 . 0.702 0. 103 0.00 5. 64 450. 64 31514 . 0.723 0. 109 0.00 5.82 450.82 32519. 0.747 0.114 0. 00 5. 99 450. 99 33469. 0.768 0.119 0. 00 6. 17 451. 17 34475. 0.791 0.124 O. OG 6.25 451.25 34922 . 0. 802 0. 126 O. OG 6.26 451.26 34978 . 0.803 0. 126 0. 00 6.27 451.27 35034 . 0. 804 0. 127 0.00 6. 28 451.28 35090. 0. 806 0. 128 0.00 6.29 451.29 35145. 0.807 0. 130 0.00 6.30 451.30 35201. 0.808 0. 132 0. 00 6.31 451.31 35257. 0. 809 0 . 134 0. 00 6.32 451.32 35313. 0. 811 0 . 135 0. 00 6. 33 451.33 35369. 0.812 0. 135 0. 00 6. 34 451.34 35425. 0.813 0.136 0.00 6. 52 451.52 36431. 0.836 0. 146 O.OG 6. 70 451.70 37436. 0. 859 0. 154 0.00 6.87 451.87 38386. 0. 881 0. 161 O.OG 7.05 452.05 39392. 0. 904 0. 167 O. OG 7.23 452.23 40398. 0. 927 0. 173 0.00 7. 40 452.40 41348. 0. 949 0. 179 0.00 7. 58 452.58 42353. 0. 972 0. 184 0. 0�'� 7 . 76 452.76 43359. 0. 995 0.189 0. 0� 7 . 93 452. 93 44309. 1.017 0. 194 0. 00 8. 11 453. 11 45315. 1.040 0. 199 0. 00 8.28 453.28 46265. 1 .062 0.204 0.00 8.46 453.46 47270. 1.085 0.208 0. 00 8. 64 453.64 48276. 1. 108 0.213 O.00 8.81 453.81 99226. 1. 130 0.217 O.00 8. 99 453.99 50232. 1 . 153 0.221 O.00 9. 00 454.00 50288. 1 . 154 0.222 O.00 9. 10 454.10 50846. 1 .167 0. 686 0.00 �2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 23 Technical Information Report City of Renton 9.20 454.20 51405. 1. 180 1.530 0. 00 9. 30 454.30 51964 . 1. 193 2 . 630 0. 00 9. 40 454.40 52522 . 1.206 3. 930 0.00 9.50 454.50 53081. 1.219 5.400 0.00 9. 60 454. 60 53640. 1.231 6.830 0. 00 9.70 454.70 54199. 1.244 7 .360 0.00 9.80 454.80 54758. 1.257 7 .850 0.00 9. 90 454. 90 55316. 1.270 8.310 0.00 10.00 455.00 55875. 1.283 8.750 0.00 10. 10 455.10 56934 . 1.296 9. 170 0.00 10.20 455.20 56993. 1. 308 9.570 0. 00 10.30 455.30 57551. 1 . 321 9. 950 0. 00 10. 40 455.40 58110. 1 . 334 10.320 0.00 10.50 455.50 58669. 1 . 347 10. 680 0.00 10. 60 455.60 59228 . 1 . 360 11.020 0.00 10.70 455.70 59786. 1 . 373 11.350 0.00 Hyd Inflow Outflow Peak Storage Stage Elev {Cu-Ft} (Ac-Ft) 1 1 . 55 1. 45 9. 19 454. 19 51350. 1. 179 2 1 . 03 0. 31 9.02 454.02 50398. 1. 157 3 0. 85 0.22 8. 94 453. 94 49930. 1. 146 4 0.51 0. 14 6. 41 451. 41 35827. 0.822 5 0.58 0.12 6.20 451.20 34646. 0.795 6 0.84 0.07 4. 85 449.85 27081. 0. 622 7 0. 98 0.06 3.33 448.33 18609. 0.427 8 0.45 0.05 2.36 447.36 13202. 0.303 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Calc 1 1. 45 0.02 ******** ******* 1.47 2 0. 31 0.01 ******** 0.32 0.32 3 0.22 0.01 ******** ******* 0.22 4 0. 14 0.01 ******** ******* 0. 14 5 0. 12 0.01 ******** ******* 0. 13 6 0.07 0.01 ******** ******* 0.07 7 0. 06 0.01 ******** ******* 0.06 8 0. 05 0.01 ****�*** *****X* 0. 05 Route Time Series through Facility Inflow Time Series File:rdin.tsf Outflow Time Series File:rdout.tsf POC Time Series File:dsout Inflow/Outflow Analysis I Peak Inflow Discharge: 1 .55 CFS at 7 :00 on Jan 9 in Year 8 ' Peak Outflow Discharge: 1.45 CFS at 8 : 00 on �an 9 in �'eaY 8 Peak Reservoir Stage: 9. 19 Ft Peak Reservoir Elev: 454 .19 Ft Peak Reservoir Storage: 51350. Cu-Ft . 1 . 179 Ac-Ft ', Add Time Series:bypass.tsf '� �::�2015 D. R.STRONG Consulting Engineers Inc Maertins Ranch Page 24 Technical Information Report City of Renton Peak Summed Discharge: 1 . 46 CFS at 8 : 0� or_ Jan 9 ,_n `'ear 8 Point of Compliance File:dsout.tsf Flow Frequency Analysis Time Series File:rdout.tsf Project Location:Landsburg ---Annual Peak Flow Rates-- -----Flosa Freq�ae:�cy Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0.220 3 2/09/Ol 21:00 1. 45 9. 19 1 100.00 0. 99� 0.051 8 11/05/O1 3:00 0.313 9.02 2 25.00 0. 96�� 0.125 5 3/01/03 8:00 0.220 8. 95 3 10.00 0. 900 0.060 7 8/26/04 7:00 0. 140 6. 41 4 5.00 0. 80u 0. 140 4 1/08/05 6:00 0. 125 6. 21 5 3.00 0. 6c7 0.072 6 10/28/05 3:00 0.072 4 . 85 6 2.00 0.500 0.313 2 11/24/06 8:00 0.060 3. 33 7 1.30 0.231 1. 45 1 1/09/08 8:00 0.051 2.36 8 1. 10 O.OGl Computed Peaks 1. 07 9. 15 50. 00 0. 98C Flow Frequency Ana?ysis Time Series File:dsout.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.225 3 2/09/O1 20:00 1.46 1 100.00 0. 990 0.052 8 11/05/Ol 2:00 0.317 2 25.00 0. 960 0. 127 5 3/Ol/03 7:00 0.225 3 10. 00 0. 900 0.061 7 8/26/04 5: 00 0. 142 4 5. 00 0.800 0.142 4 1/08/05 6:00 0. 127 5 3.00 0. 667 0.074 6 10/28/05 0:00 0.074 6 2. 00 0.500 0.317 2 11/24/06 8:00 0.061 7 1. 30 0.231 1. 46 1 1/09/08 8:00 0.052 8 1. 10 0.091 Computed Peaks 1.08 50. 00 0. 980 Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS ° ° ° - 0 0 0 0.004 27656 45.101 45.101 54 .899 0.549E+00 0.013 8206 13.382 58.483 41.517 0. 415E+00 0.022 7711 12.575 71.058 28. 942 0.289E+00 0.031 7206 11.751 82.810 17 . 190 0. 172E+C� 0.040 4927 7.220 90. 029 9. 971 0. 997E-G� 0. 048 2584 4 .214 94 .243 5.757 0.576E-5"� 0.057 1400 2 .283 96.526 3.474 0.347E-0_ 0.066 1075 1.753 °8.280 1.720 0. 172E-OL 0.075 574 0. 936 99.216 0.784 0.784E-u2 0.084 18 0.029 99.245 0.755 0.755E-02 0.092 57 0.093 99.338 0.662 0. 662E-02 0. 101 66 0. 108 99.446 0.554 0. 554E-02 0. 110 71 0. 116 99.561 0.439 0. 439E-02 0. 119 99 0. 161 99.723 0.277 0.277E-02 0. 127 37 0.060 99.783 0.217 0.217E-02 0. 136 5 0.008 99.791 0.209 0.209E-02 02015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 25 Technical Information Report City of Renton 0. 145 16 0.026 99.817 0. 183 0. 183E-02 0.154 8 0.013 99.830 0. 170 0. 170E-02 0. 163 9 0.015 99.845 0.155 0. 155E-02 0. 171 10 0.016 99.861 0.139 0. 139E-02 0. 180 11 0.018 99.879 0. 121 0. 121E-02 0. 189 12 0.020 99.899 0. 101 O. 101E-02 0. 198 15 0.024 99. 923 0.077 0.766E-03 0.207 18 0.029 99. 953 0.047 0.473E-03 0.215 14 0. 023 99. 976 0.024 0. 245E-03 0.224 13 0. 021 99. 997 0.003 0. 326E-04 0.233 0 0. 000 99. 997 0.003 0. 326E-04 0.242 0 0.000 99. 997 0.003 0.326E-04 0.250 0 0.000 99. 997 0.003 0.326E-04 0.259 0 0.000 99. 997 0.003 0.326E-04 0.268 0 0.000 99. 997 0.003 0.326E-04 0.277 0 0.000 99. 997 0.003 0.326E-04 0.286 0 0.000 99. 997 0.003 0.326E-04 0.294 1 0.002 99. 998 0.002 0. 163E-04 0.303 0 0.000 99. 998 0.002 0. 163E-04 0.312 0 0.000 99. 998 0.002 0. 163E-04 Flow Duration from Time Series File:dsout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS ° ° ° - 0 0 0 0.005 27680 45.140 45. 140 54 .860 0.599E+00 0. 013 8302 13.539 58. 679 41.321 0.413E+00 � 0. 022 7639 12 . 458 71. 137 28.863 0. 289E+00 �!� 0. 031 7204 11.748 82.885 17.115 0. 171E+00 , 0. 040 4349 7 . 092 89. 977 10.023 0. 100E+00 � 0. 049 2617 4 .268 94.245 5.755 0.576E-01 ' 0.058 1388 2.264 96.508 3.492 0.349E-01 0.067 1069 1.743 98.252 1 .748 0. 175E-01 0.076 584 0. 952 99.204 0.796 0.796E-02 , 0.085 24 0.039 99.243 0.757 0.757E-02 � 0.094 52 0.085 99.328 0. 672 0. 672E-02 � 0. 103 68 0.111 '99.439 0.561 0.561E-02 ' 0. 111 74 0.121 99.560 0.440 0. 440E-02 0. 120 94 0. 153 99.713 0.287 0.287E-02 0 . 129 42 0.068 99.781 0.219 0.219E-02 0. 138 7 0.011 99.793 0.207 0.207E-02 0. 197 15 0.024 99.817 0.183 0. 183E-02 0. 156 8 0.013 99.830 0.170 0. 170E-02 � 0. 165 7 0.011 99.842 0.158 0. 158E-02 0.174 11 0.018 99.860 0.140 0. 140E-02 0.183 11 0.018 99.878 0.122 0. 122E-02 0. 192 11 0.018 99. 896 0.104 0. 104E-02 0.201 15 0.024 99. 920 0.080 0.799E-03 0.209 19 0.031 99. 951 0.049 0. 489E-03 0.218 13 0.021 99. 972 0.028 0.277E-03 0.227 15 0.024 99. 997 0.003 0.326E-04 0.236 0 0.000 99. 997 0.003 0.326E-04 0.245 0 0.000 99. 997 0.003 0.326E-04 0.254 0 0.000 99. 997 0.003 0. 326E-04 0.263 0 0.000 99. 997 0.003 0. 326E-04 02015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 26 Technical Information Report City of Renton 0.272 0 0.000 99. 997 0. 003 0.326E-04 I�, 0.281 0 0.000 99. 997 0. 003 0.326E-04 ' 0.290 0 0.000 99. 997 0. 003 0.326E-04 �� 0.299 1 0.002 99. 998 0.002 0. 163E-04 ' 0.307 0 0.000 99. 998 0.002 0. 163E-04 0.316 0 0.000 99. 998 0.002 0. 163E-04 Duration Comparison Anaylsis , Base File: predev.tsf , New File: dsout.tsf ' Cutoff Units: Discharge in CFS ' -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New oChange Probability Base New oChange 0.075 I O. 10E-01 0. 82E-02 -20 . 4 � O.10E-01 0.075 0.073 -2. 6 0.093 � 0.70E-02 0. 68E-02 -2. 8 � 0.70E-02 0.093 0.092 -1. 9 0. 112 � 0.48E-02 0.43E-02 -8. 9 I 0.48E-02 0. 112 0. 109 -2. 6 0. 131 � 0. 31E-02 0.22E-02 -30. 9 � 0. 31E-02 0. 131 0. 119 -8. 9 0. 150 � 0.20E-02 0.18E-02 -12 . 1 � 0 .20E-02 0. 150 0. 140 -6.3 0.169 � 0. 15E-02 0.15E-02 -l. l � 0. 15E-02 0. 169 0. 168 -0.3 0.187 � O. 10E-02 0.11E-02 9.5 � O. 10E-02 0. 187 0. 192 2. 5 0.206 I 0.78E-03 0.62E-03 -20.8 � 0.78E-03 0.206 0 .201 -2. 6 0.225 � 0.57E-03 0. 49E-04 -91. 4 � 0.57E-03 0.225 0.207 -8.2 0.244 � 0.33E-03 0.33E-04 -90. 0 � 0.33E-03 0.244 0.216 -11. 6 0.263 I 0.20E-03 0.33E-04 -83.3 � 0.20E-03 0.263 0.221 -15.7 0.281 � 0. 15E-03 0.33E-04 -77 .8 � 0.15E-03 0.281 0.223 -20. 9 0.300 � 0. 98E-04 0.16E-04 -83.3 ► 0. 98E-04 0.300 0.224 -25.4 0.319 � 0. 16E-04 O.00E+00 -100.0 � 0. 16E-04 0. 319 0.317 -0. 6 Maximum positive excursion = 0. 005 cfs ( 3. 0°) occurring at 0. 177 cfs on the Base Data:predev.tsf and at 0. 183 cfs on the New Data:dsout.tsf Maximum negative excursion = 0.083 cfs (-26. 90) occurring at 0.308 cfs on the Base Data:predev.tsf and at 0.225 cfs on the New Data:dsout.tsf e 2015 D. R. STRONG Consulting Engineers Inc. Maertins Ranch Page 27 Technical Information Report City of Renton PEAK PLOT ��,..n.a.,�..,�,.K;R,s - � �.� — --------- --- ----------- j'� a.ah,m aenoa 2 5 10 20 SO 100 � 10� :. �dou[.pks m LandsDurg ♦ dSaS�ks c� pr�c_^:pks ♦ 10° 6 N k LL h V L � „ L R • r - � � .. � . � t0� i � � • I • c i i � I �' I' �, 10� 1 2 5 10 20 30 40 50 80 70 BO 90 95 98 99 : �� CumWatne ProbeDiMy : (' � ��— ---------------------------- ---------------.....---._. DURATION ANALYSIS - ----------- -- ----- ___------ e..�.a-a..�.,,�.-��s ----- .-� � a rdvul dur � tlsout dur ♦ tarqst�ur � !i i� � _.__��' - 0 ly 2 �� '��_ „" \\ �F� :� R - � � � N I � O ; u � ~� 000 �q 'e o v, o0 � �._ : 0 ,. o o_TT �rTT'I7 ��. .. 10 5 tOd 10 3 10 2 10 � 10° 5 Pro6ebiily Exceedence . .._____..__ ._.__.___.... _. . ___... __ _ ...__.. ��2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 28 Technical Information Report City of Renton WATER QUALITY TREATMENT SYSTEM (PART E) i 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 StormFilter following the detention vault will accommodate this requirement. C�2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 29 Technical Information Report City of Renton FIGURE 7 ', DETENTION 8� WATER QUALITY FACILITY DETAILS i�2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 30 Technical Information Report City of Renton SE 1/4 SECTION 3, TOWNSHIP 23 N, RANGE 5 E, W.M. X vi�AER TINS RANCH X fRAA!£ANO 74" X ROl/ND SIX/O COY£R I NARKED bRAlN'NITH X R�3 37.85�(�, X SiIO'LWAIE X - PoN I56.5{' FRMIE AND 21' ----_� �ua+-rn�rsrc euawc) s'xra'cn��e w�a�a�ie.pwa�wn+ �=. �° zxz'�cc�ss cweNnrc �t4ss.s�' locrnvic eacis(rn.) L9 if STLY7UF7LTER MANHIXE EL.�57.8Y EL�56.SI' (NLW-TRAfF7C BEARINC) RMl�3{SB.PO' FW/SN£D RIN=tISH.00' - - — DETA2 pJ SHEE75 C9 ANO C13 �+��, 2'X2'ACC£SS OPENMC �RlM 345�OS" CR.apE RIAI t458 00' T w �rnat7 smucTuaf as'F7eeeeoARD . . , 7 ��• � ��i��O��i��%'� `�'��.�\��`��, ��\\/\\/\.\,�.��'.�\�,��\ �T �C[N' i:i �i< /i✓✓/� � ii�i`iii,,, ij�i/FF r �� n✓iEr e-v� e�. �ss.so' � i i �� iJ� i i i i � � r i.i i..) i i i �i ��ri � � �� t �� IE 41500 Wi EL t�56.51' �� l � � ��i\�i\ ��\ ., r�� j��j�\�\/T\. \//\/.�� /`�� ? I 1B'INCET IBOV 4N.50' lE 45550 454.00• � _ �� ./://�/<�l/ /%.i>r��`. �� •%A� ;.�:`V��`� � �'�`y'��i��i��- ��"i �, ,�- ,�, � i,> � ;��i,, i.i�i-i. � � I£ISQ25 iH'Ov1ET g � . � � • ,., . `• a • ''�' _ • • - £L 45450 a z a • ____7____Q`L FR�'@QAh�)__ Z IBOV N{. I' / lE 150.?5 • Q. ISf.QO ____ ____ � ____ _______ _____ _______ "__' ___ _____ � Q � � i � A m�x�rs��j �aso' W _ - - - - �' I � � ,�ua�rr nuer e- � 6'PYL WLET i � �� RUNCS(TYPJ ' ' ' _ ' PYC PERF. �. I£15150 R �ADD UDDER !£�53.JJ . Z �eov��.�3' � a se.sp' I ror a�seonu�N�sravAocEo o`� te'�� auNcs(rra) - � - - � ma sp• 0 srnucn� ,��R � � o rd' as'wrxiuuuu �a•ouner - - R+.w�(rna)� c - - � 1 � � � TRACT:4" smua�r srar�c� �.+s.00 _ w I �rw.) -- ---- - -- - - - - - Q ' �k^�k.•; I fL.,..50• 5 Q,.,.50� - - - - - c I h��,h1� . ma�vawr _ - L � lo`,po..l I �� - - n..-IM.sa I I I � :Y�X�' EL I�f.4i' __ __ _ " - _ p�_' _ _ `'_. __ __0.5l S�CFSEOIAIEN7 _____ _____ —EL 111.0110 � � � � I 6'PERF.FOOT4fG �� . . . . I � � DRAlNS(lYP). ' 'a '•�. ' g CONN£CT TO CB 10 0.67' 6'PERF.F0071NC O.5'A1MIIMUM• � � p � I �O� ORA/NS(TYPZ •SEDIM£NT STp7AGE � I p I I car+Hecr m ce ro �rra.) � p � s.sr r�.6r �ss.ao• � � ss 15.s - � '�00� _ � i �•XT�•� I RlSER��"'rrn'E.j�'� DETEN710N VAULT SEC710N A—A ^ DETENJION VAULT SEC710N B—B `8' � � � � I NORIZOHTAL SCALE: 7"�20' NORYZGWTAL SC.1LE 1'=70' � � B � 4ER77CAL SCdIF. �•_{• YER7ICAL SCALE I•=4� I i a ! � i' i � i • � �r»,� o � �1 �1 `° I � � : ��'�� ^ � `s � i 4 m i�m p � � '�=a: '-: I � � �> , ; m �m�� mm � o a �� , E�� , N�. � � E I I Sk10'pPA1E ?�Mqr .02 h7./FT 2.1 � �� R1N t456.51'(NQV-1RAfF7C �� '�Q�- � � � �� 5� � er�anvc) ��k�, '� Z'X2'ACCF55 OPEf/INC / �`�/' // � � iTP.�IYP. ��%�� , . I � � I ��ti�� . . . 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GALVAHIZED HPE PAR75 TO HAl£AS�FIACT 7REA7MENT 1. < ^ � � ______________ ____ ' __5��gp��y� .I fRAA/E AND lAODER OR STEPS P'FSET STl. `� DETENTION VAULT PLAN = as.. A d£ANOUT GA7E IS N98LE FRPM TC1�. o SL'AIE: 1•=P�• 1"SECRON Q�PIPE ____ N � . G FRAME�S d.EARALI�C!/RB.AR LK PogR AND p.£ANOUT CAIE. ATTApim BY GASKE7ID � BAND TD A(LOW REMOVAL � H f.lF METAL WTLE7 PfPE CONNEC75 TD C£7VO/T LQVCRElE PIPE ^ ' 2 . �TLET PfP£70 HAY£SMOOTH O.O.EOUAC TO CQNCREIF PIP£LD.L£SS u� �M7Ff OR�Li AS SPEGFl£O 3 A LlIE STq4AGE VOG!/ME CF h S PRONDE A7 CEA57 ONE 3"Y.090 GAUGE SUPPORT BRApC£T ELBOW RESTRICTOR DETAIL j T 1 ' ANOIQRFD 70 CCNlCRETE WALL(NAXLVUN 3'1£R71CAC SPAfJNGJ NIS . C 1 YEAR <54.19 1 . F 4 4 I � . . � 6.LOCAIE QBOW RESIRICTqt(5)AS NECESSARY TO PRONDE YOYq/UN �, 4 � CTEARANC£AS SHON?l. " 49 rssmicroa vu��nn,aa�cE 7.LOCATF AODIIIONAL UDDER R(/NGS 1N 57RUC7UI4E5 USED AS ACCESS IN COMPUANCE WITH CITY OF RENTON - �x�;M•suuP,�a �_ �.�o-o.G TO TANKS OR V.IULiS 70 A110W ACCE55 NF1EN CATpI BA9N IS f7LLED DRAWINGS NOT APPROVED STANDARDS � DETENAON SUMMARY SHEET �SIMP EDQD SHQ'Q5�1E0J """""'�� FOR CONSTRUCTION UNLESS ev. �ate: _ DETENAON VAULT SECAON C—C !C� CONIROL S7RUCTURE W/FROP—TEE) i STAMPED OR SIGNED APPROVED BY: Date " CON7ROC S7RUCTURE NT5 Nr� � BY TFiE REVIEWING AGENCY BY: Date: _ � �.�.,.�, BY: Date. ' ��iFm's"°,�Lai A�I V�Y ; ao�n�vcs�c �� s Ho�o = �'� �: � CITY OF MAERTINS RANCH o�.sa.so�s Cd 2 WorkG�Dsye Before You Dip �' D.R.STRONG �� Y� � � R E N T O N � 811 q �� D � � CONSULTING ENGINEERS °^^�„�,� � �.o� �� STORM DETENTION VAULT X-SECTIONS DEfAILS �� Ulitiealhxler�oundLocedonCenbr G'"FS�Rc',.�'� �'�S R��ames st�vt�ro�es ""�"y� �� Plann��5,B�ildin5/Public N'orks Dept. C12 � (D,D.fiND,OF�WA) ��o,-,,. �-rn+��-,�,.�.�� No. R_vs�c�,u �� .TE APPR � ��°�� PERMITS: U15-001308, B15-000196 o,zsaz,�s,F.z,.��.n 1w �""1s "Eo � DRS PROJECT N0. 14103 A - N N N N A A SE 1/4 SEC110N 3, TOWNSH/P 23 N, RANGE 5 E, W.M. " MAERTINS RAN�'H x x x X cmimncrar ro cww�ro ' FMNSH£O GRADE x CRADf RMG/R/gR5 STC�4Nh7LlEk DESIGN NO7E5 /� A",T"•�� ""� i X CRAOE RING/AISERS SR?VAIf7LTER TREARfINTCMApTY IS A FUVCTIQV Q�THE CARTR/P;E 5£CECIKW AND 7HE NUIIBER Q�G.1R7RQ)GES THE r a,�� I�• '� �I STANDARD MANHqF STRE!S 9WNN MIN TNE NM7M/M NUMBER OF CAR7R1OCE5(7J. KILUA/£SYS7EY!S ALSp � r`. �1 I� �i� - _ AVA2ABCE MI7H MAXl1/!/M 7 GR7RIDC£S _ ' � � . I77'NANMIX£SRY2MF7LlER P£AK HYDRA(21C CAPAp7Y 15 7.55 CFS /F IXE 97E CpYDl77P45 EXCEfD 1.5 CFSµ I I �� ' UPSTREAI/BYPASS 57R!/C7UR£f5 RfIXIME�. � "�"�"'��"` . t _ .•.1. 's C<R,.�OCE SE2ECiiCN -«_� I � I � �� '�. �� C/R,. D'..£HEIGHT pT 7H LOW ORCp I I � � � �, s� PECGAIM_NDED HIZWAULICOROP N 3.05' 23' 1.H' �T��. . � _ '� �`�:� ' � " �acC��F��WRA7F 2 m ff 1 /t 2 m k 1 m ff 7 !t 1 H � � � � �' � FLOATABLES ��prp�,��FLOW RATE m 22.5 77.25 I 7. f0 9 �(}\C�� . ?� = R �E 1 ._ P Q � s�r�s��c �� -- w..E. ..�...._......,.::��m,�,.�. ,e...�.� �- �� OATA REOUIREMENTS • � �e••.m•,• x �'1 � c � �, o� STilUC7URE 1D cerr � .a.._.,=.,_,a '�"' ��, � ¢ � WATER GUALI7Y FLOW RATF C!s 0.072 • o o !'� /: �i* (/� � �. R=2 ='� PEAK FZOW RATE cf5 I.fS ` �i�� , �� 7B'INLET PoP£ p�- � Z /E 44f.92 '�� j=� FETURN PERfCD OF PEAK FLOW ipp � yl x��w�e�^` � OF CAR7R/DGES REOVIRED 5 � W�� ,e,e„ CARTRIOG£FLOW RATE 3 �5 I 4' I 4 Q-.� (`'WITa'N YEOIA TYPE C5� P£RLITE ZPG GAC PHS z •�'^'^�•°'r t' ;• �' / �...m.��.��.d.. . � �Vo � ��w� �yf 2 P/P£DA7A: l.f. NA7ERIAL pl.WE7ER .��o,v '^'�^^"a �" ��•�� Q lNLET P/Pf .92 LLPE 18-lNCHES �.�.�� srs. �"""�°"`�`�"" 5 1 c ,s rw�r r�PE . . . -�:� ...,..... C � OUTLET P1P£ 262 LCPf 1?-MfIiES _ .. •••••p•_• �� ' `' �a.m.�,..,s.m.� ..r FRIER CARIRIDGE R1M ELfVATlOW • s�r.y�O' . . . � � r.a...r..a W..• '•• - W71E75U�1lP eer.ceu�+o:cs: ,..� +�.,.��-.�.r.._ms�r�. FLOW K!T �NZ62 ANTI-FLOTATIpY 6ALUST WOJH HfIGHT �TM�ym�Yebmti�� - s r`�:�s� NDPF 11'OUi1ET R/5ER FRAMEAND COVER NOTES £GAL REIX/!R£NENTS: d�"^'°��rn6�� '""�"`��' '• (DIAAIE7ER VAH/ES) z .q,r.cnp,rae. S..' � I SECT/ONA�1 N.�s .�w..�.m �. � `;`` .� _� i, •PER FNGlNEER OF RECORD ��tl� � \�/�� N.7.S .o�.enpt . , . �' , /I .,i„W J I auner GENERAL NOTES: � - - .. � � �.i�� 1.CQ4TECH TO PROVIOE ALL MA7FRlALS!/NLESS N07ED 07HERMiSE. _ � 2.D/N£N9CYJ5 YMKED N1TFl(J ARE R£fEFENC£D/M£N9QV5. ACNAL DN/EX9QY5 MAY VARY. J.FIX7 SIiC SPEpFIC ORAMWGS N1Ri DETAILEO VAULT OIVfNSlONS ANO 11£/CH75 PY.EASE CQ4TAC7 KNIR CpV7ECN «M�w��p sM Nu-tm1 �i� ��_ym� � ENClNEEREfi SIXUTlOYJS LLC NEPRESFNTf11�£ ri.confeWESttm - ' Mnwut��t ppc o � �„ a urcH awana rne� �.STORMf)L7fR WATFR O(/AClTY S7RVCNR£SHALLrBE/N ALLQPD,ING�WTN ALL DESlCN DATA AND NJf0Y7MA71pf �P'�"'"�`� ��uy� � tF°"a-'�� _ � � � q ,q CQYTA/NED IN 1N15 ORAM7NC. 5.SIRUCIIME SHALL MEET MSH70 H510 LOAD RARNQ ASSVWNC EARIH COY£R QF 0'-5'AND CROUNOWATER � � E(EVAPpV A7, OR BELOW, THE OUREf P/PE/NIERT ELEVA7IQY. ENCINEER Q�R£CQRD 70 CP4FIRM ACNAL CRO!/NOWAIER ELEVAT7CN. CASTlNCS SHALL N££T AASHTO M306 AND BE CAST IMTH 7H£CQYTECN LOGO. FL�OW t i -- � 6.F/L7fR CAR7RIDGES SFIALL BE NEDIA-f7LLE0,PA557YE.4PNCW ACNAIED,RAOIAL fLOW,AND SELF CYEAN/NG 1B"MLET -- RAO/AL MfOlA D£A7N SYA(1 BE 7-INCN6 FIL7ER 1lIDIA CONTACT 7WF SHALC BE A7 LEAST 39 SECONOS / I2�OY/RET 7.SPEpF7C fLOW RA7E IS£OUAL TO 71i£f7LIFR 7REATNEN7 CMAdIY � o � A�(Q`r) (Awn)O/NDfD BY THf F7LTFR Gt7MlTACT SURFALL n•�.o.waxHacr /NSTALLAnON NOTES.• � STRf/CTURE e �•••w••'•• B . 1. ANY SUB-BASE,BAdCF2L DfP]N.ANp/pp AN71-F(07AAON PRON9Q45 ARE 97F-SPECIFfC DE9GN LdJSAQERATKWS � i�� ,�,,,,�„o,,,a�,��,,,, � �. AND SHALL B£SPEGFIED 8Y fNG/NEFR Ll�R£CORO. � �� ' �8��QQ 2 CLWiRAC70R TO PRONO£EOUIPAIEN7 N17H 5f/FF/CIENT fJFTMC ANO R£Apl CAPAp7Y TO Lff7 ANO SET 71fE t � ' i \ ;j`R"v" � STORMFKTER S7RUCTURE(L1f71NG LLUiLM£S PftOHOm). ..r.�r..s.u.e o f � ', I � 3.L0.NTRACTIM TO INSTALL JpNT gALANT B£7NEEN ALL S7XUClUR£SECAQVS AND ASSEYBL£57RUC7URE � � �`^'" �"" � '�. 4.CLWIRACTOR TO PRONDE,INSTALL,AND fRWI INL£T P/PE(S). ' �`� I 70P AA6 ACCESS 5.C0.V7RACTCR TO PRONDE AND MSTALL CQYN£CTOR 70 THE WIZFT PoSER SNB. STORMF7L7FR EO!/IPPfO M17H A !r�� .j - '', SEF FRAME AND C04£R DVAC D/AA/ETER HDPF IXITLET SNB ANO SANO CLYLAR. IF OURET PWE lS LARGER 7HAN H WCNE$CCW7RACTQY TO .�/ � � 'i OETML PLAN VIEW REA104f TNE 8 MCH IXl11ET SNB AT Mp.QED IN C(JT UNE COVIPLINC BY FERNCO AP EWAL AND PRC1NDfD BY - ' CCW7RACTOR. y� \ � - ^"+ �'. STANDARD OI/7LE7 RlSER �°'��` d r 6.Cbtl7RAC70R TO TAKE APPRL1�fiATE MEASURE$TO PH07FCT CAR7R/OGES fRQV COIJSIRLC770M1-RELAIED EFOS�QV ' �� Fcowrnr.� u� auNcrs. /�" � : ::� .,e�r=.--} . STORMFILTER DETAILS �� ' �� Hrs ..�.........�„r..�a,,.o. � �,..�...,...�,... `� `.t�_I�I, .�� ^�'.�"•� � � � � M��:';d � � i NP4 NOYEN GEOTIXlRF FAHRIC MIRM7 ♦. � .um.e.e wr.�.,.�.m ��/�e isON OR£OU1VAfENT ALQYC R1P TO �^bti«I+ae>+.ti�++ro.�+'1 T�1��. REIIAiN IN PUCE UNR!AU. �• ry�� y�� I �„� ,Q�, `�,,,�, CON57i7UCT7P4 AND 502 STA8/LlZAT101V °� I lNCLUqNG LANOSCAPINC FQP 7X£ y,��ffi^�•^'�`^"1P'r' .� � �, lND.'NOWL RE9DENC£5 15 MISTALLED. � Y�_Y;�_�� ' CU7 A7 SURFAC£ANO RENOVE UPLW a�.. r.�..s...a>w�.r.e.,. �'��9 _ CPVPLE7lON OF 7NE INDINOUAL LOTS ms�s+a �.r .r...da�urr...�rr.r� e�_ -_ -_ Of7ECTABL£ �� r�s r.r�«i •••"�••m•�� I`•'� .a m " _ ___ tocn�orr r�w£ � ... � _ _ `q., m�. �� _ --- � yi � � I ' �'�._�..a .a� -- - � a m--' �.,_.��.��.,y,m.,. ��... z _ � �� ' . .�.�.. -- ' � � :�r��.�:.�..�..�. -�� + NpJ MV4EN f#O1FX7HE FAAR/C ��ew �- _ W 1 ANRAF7 11QN Q4 fIXllVALENT ..e,e. .au. °`••"'��-"��••� � � ' � `WA9iED AlQVG BOTT(!M M!D SIDES .s..r..��c.n. u.sr.w..sr.ws.v r.�.��:.f�.�'"�.�a�wmur � !M � � ORAM ROdf 6'ANO 8'DlA P£RFL14A7EIl GPP m�se:ww"ar�r•••�"�'�� •�.•�rarw � IX7 6"AND 12'IXA AS7AI JOJf am.n�n-sooso �sm.ru�-smm $(M J$PERFORA7ED Pl'� � Ge:aAr'YeFT ', ��M MfIN ME�L - � � �,_ F Yu.� i'1:?F cqp�� GTCM B11iM 1'Y'E] YA3CH 2O00 �C �s•-zs'w�s�+eo vn�av Rorx r.a�_:��a -� � 7/1"PERFp7A71pV5 ON 5�CENTERS. 6"M/N/uUM ROMS SHACL Bf SPACED 720 DEGREES MART r 60 OEGFEFS � r�� DRAWINGS NOT APPROVED �N COMPLIANCE WITH CITY OF RENTON - STANDARDS L FOR CONSTRUCTION UNLESS gy. Dale: INTERCEPTOR TRENCH STAMPED OR SIGNED APPROVED gy: Date: ` N75 BY ll-1E REVIEWING AGENCY BY: Date: � E � BY: Date: n �y�j € PaF.�i�+s JOLO - �'�o �' d\1 �Y �� N� _` ' '" �� ,� CITY OF MAERTINS RANCH Yo�.2o.so�s � s HOLDINGS LI.0 �S5 ' Cel 2 Wakig Daye Belaro You Da � D.R.STRONG °�wu � ' ys CONSULTING ENGINEERS �Y� � '-"t� R E N TO N � 811 �o `�: D D � ��S """`iwc I -1 � STORM DRAINAGE DETAILS a...s�. 5 ��+�d�a�+�en� �`F�� D � I .,u.�..� I Planrin�/B�ildiry/Public Works DepL �C13 (Q1YfT.FD.ORWA) SfG��A'.. � Gp-mr�vFM�proa.u�.w�6bax+ N�. RE1'ISION �Y DATE APPR ,,,,�IMI � o,�ffi„�,F.�.�,Z,1, ,,,,, s'-="��"�' PERMITS: U15-001308, 815-000196 �' �s "so DRS PROJECT N0. 14103 A - N N N N A A C=::=NTECH� ENGINEERED StaLUTIONS Size and Cost Estimate Prepared by John Megrditchian on February 5, 2095 Maertins — Stormwater Treatment System Renton, WA Information provided: • Total contributing area =4.079 acre • Impervious area = 2.05 acre • Detention release rate, Qtreat = 0.072 Cfs • Presiding agency =City of Renton, WA Assumptions: • Media = ZPG cartridges • Per cartridge flow rate = 7.5 gpm • Drop required from inlet to outlet= 2.3' minimum Size and cost estimates: The StormFilter is a flow-based system, and therefore, is sized by calculating the peak water quality flow rate associated with the design storm. However, when the StormFilter is placed downstream of detention the flow rate generated at the water quality storm is not always representative of the total volume of water that will go through the system or type of pollutant-loading the system may experience in one year. For this site, Contech Engineered Solutions LLC recommends using a 72" Manhole StormFilter with 5 cartridges (see attached detail). The estimated cost of this system is 21 300, complete and delivered to the job site. This estimate assumes that the vault is 6 feet deep. The final system cost will depend on the actual depth of the unit and whether extras like doors rather than castings are specified. The contractor is responsible for setting the StormFilter and all external plumbing. Typically, precast StormFilters have intemal bypass capacities of 1.8 cfs. If the peak discharge off the site is expected to exceed this rate, we recommend placing a high-flow bypass upstream of the StormFilter system. Contech Engineered Solutions could provide our high-flow bypass, the StormGate, which provides a combination weir-orifice control structure to limit the flow to the StormFilter. The estimated cost of this structure is $4,500. The final cost would depend on the actual depth and size of the unit. �O?012 Contech Engineered Solutions LLC 11835 NE Glenn Widing Dr.,Portland OR 97220 Page 1 of 1 «ti�1v.ContechEti.com Toll-free:80�.548.4667 Fax:800.561.1271 TS-P022 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 the multiple catch basins. Pipes are typically twelve- and eighteen-inch diameter LCPE material. The pipes will have a minimum slope of 0.50%. The vault primary overflow riser is designed to convey the 100-year peak storm (design storm), based on the KCRTS 15-minute time series for developed, undetained conditions on site. This is calculated at 3.58 cfs. The results of the 15-minute KCRTS time series, overFlow riser analysis, and KCBW Calculations are included in this Section. DEVELOPED 15-MINUTE TIME SERIES Modeling input Land cover Entire Site � Till forest(ac) 0.00 � Till Grass(ac) 1.71 Wetland (ac) 0.00 Impervious(ac) 2.30 Scale Factor: 0.85 Time Step: 15-Minute Data Type: Reduced Project location: Landsburg Total Area: 4.01 �2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 31 Technical Information Report City of Renton DEVELOPED 15-MINUTE TIME STEP MODELING OUTPUT: Flow Frequency Analysis Time Series File:dev-l5m-�n. tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flo�•i Freqaen�y Ar.alysis - Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 1. 10 6 8/27/O1 18:00 3.58 1 100.00 0. 9°0 0.798 8 1/05/02 15:00 2 .45 2 25.00 0. 960 2. 45 2 12/08/02 17: 15 1.54 3 10.00 0. 9UU 0.882 7 8/23/04 14:30 1. 47 4 5.00 0.800 1.47 4 11/17/04 5:00 1.34 5 3.00 0. 66i 1.34 5 10/27/05 10:45 1.10 6 2.00 0.500 1.54 3 10/25/06 22: 45 0.882 7 1.30 0.231 3.58 1 1/09/08 6: 30 0.798 8 1. 10 0.091 Computed Peaks 3.20 50. 00 0. 980 FLOW CONTROL PRIMARY OVERFLOW Using standard orifice equation to determine stand pipe diameter in control structure Ref. KCSWDM '09 Figure 5.3.4.H Q�oo = 100-Year Peak Storm calculated using KCRTS 15-Minute Time Steps Q,00 = 3.58 cfs HMAx= Maximum available head in feet measured from crest of weir HMAX= 0.5 ft. D = Riser Diameter D = (Q�oo/(3.782 * HM,�xc s��o s D = 1.16 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 peak storm H = Actual head above weir achieved with Q,00 H = (Q,00/(9.739 '` D))^0.67 H = 0.39 ft. 20'� D R STRONG C2��:I��,q Er:��=er I�� P,1aerti�s P.=.��'� P�oe:!? BACKWATER ANALYSIS �' C2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 33 Technical Information Report City of Renton J I i , ��._ i i I I .� I I I - ._ � I . I _ , 3 _ W f � < ' W 2 , I I � ,l I y � G C9 �ii � p � . , � i 2 2 � 3 a ' • . . � . + � I _ _L_ , � � y ? � � � NE 96THST I ----- 2 w � � I I—— R� � I R2 J � O � W � �_ . � — �= 1.972 R� I a 2 r: 3, y � � — —� � R100 i � ? � e ( �----� T,a99'"S.F � � � I � � I i i � ,f, �-----� 0 W � j 1 � I �A I � 93 j � I � I I L301 I I ��" � L3 � � �� 9,848 S.F. � 9 150 SF � a . � L----J cn I �-�---J � � � . I �'' � ry I r————� I �————� � I I � � 2 � I I � �2 !� � � I I I I i M /1 I I I � I _—__ I � I �----J L----J i ,"�: — �I i-+ , • � � � 2�»o S.F� , � �� ` � I 3 I �� I �� I 1 � � � � � � � �; I L1001 I !--- I y � 26.934 S.F. ' I 2.337 S.F. \ \. — J L----� ---, �--- —� ' � �------ � , ' \ \ � ll I II� � 11 ,1 �� Z \ J �. I 4 ,1 ' 1�1I D � 1 vo'unurr � Q = Z � • \ ` 1 LFAS£A1ENT ————J � U W f^ � 1 1 � Z ¢ Z � �-------� r----- -- � � � �u � o � \ � � I , I �i 9 Q � � � � i � � , z . i �------- Q oo � � � �------- U � o Z � � / � I ��, � i 8 m .� w ` / � � � / I L6 I N � � 20,055 S F. I \ ' r" L——————J � I � ——— � I r---- —� , / � � � � , � \ \. i ! �, ' � i � � � `�� ____ � \. , \./ ,��,�____l � � � �; �, � \ \ I I R7 I' � s � i \ � 7,307 S.F I' L7 � \ \ I '/ 27,�462 S F. � � �_ _� N O RT H DRAF7E0 8Y.• NAK � ' I / ��---� GRAPHIC SCALE DESIGNED BY.� NAK \ � O 4O OO �2O PR0.IECT£NG1NE£R: MAJ I � . /� JF' I � � DATE: Q7J2.2015 � � � I I � � PROJ£CT NO.: 14103 \ � � ^ ,r M , -,- ' 1 INCH = 80 FT. .� ..��,.� �� cw. � ��o� ��' n _� � � � � I � �--- -� . I � F7GURE. ;,c�� 74� - ��g\,em �»o7�i i�, FV Po Fl�'j�.i��.T n�7u:s �R ST7.IJ=CL=JSJLTIPJ�` FV_ �� JC Path: c:1bw 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(C�"A�)/Aroca� T�Time of Concentration(Typically 6.3 minutes which is the minimum value used in calculations) R=design retum frequency iR= Unit peak rainfall intensity factor iR=(aR)R�)"(-bR) aR,bR=coefficients from'98 KCSWM Table 3.2.1.6 used to adjust the equation for the design storm IR=Peak rainfall intensity factor for a storm of retum frequency'R' IR=PR'iR 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 retum frequency'R' QR=C�"iR'A The Q-Ratio describes the ratio of the tributary flow to the main upstream flow. R= 100-year storm I aR= 2.61 ' bR= 0.63 PR= 3.95 inches Conveyance System Variables: d= pipe diameter n=Manning's Number 1= length of pipe 02015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 34 � Technical Information Report City of Renton Pipe Structures Subasins& A A C C� T� iR IR QR SQR Q- d Ilateri� 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 fps ---------------------------------------------------------------------------------------------------------------------•--••------------------------------------------------------- CB#7 TO VAULT INLET 1 6 7 6 7 38331 0.88 0.61 6.3 0.82 3.23 1.74 1.74 0.00 12 LCPE 0.012 83 1.00 470.61 469.78 473.90 3.87 4.93 0 2 RUN 601•6 6723 0.15 0.90 5 6 5 6 13242 0.30 0.80 5 6 5 6 19965 0.46 0.83 6.3 0.82 323 1.24 2.97 0.71 12 LCPE 0.012 70 1.00 469.78 469.08 473.22 3.87 4.93 0 2 4 5 4 5 1859 0.04 0.90 6.3 0.82 3.23 0.12 3.10 0.04 12 LCPE 0.012 192 1.00 469.08 467.16 473.76 3.87 4.93 6 2 RUN 401-4 34479 0.79 0.62 3 4 3 4 19901 0.46 0.81 3 4 3 4 54380 1.25 0.69 6.3 0.82 3.23 2.78 5.88 0.90 12 LCPE 0.012 128 2.59 467.16 463.84 472.16 6.23 7.94 0 2 RUN 302-301 1880 0.04 0.90 RUN 301-3 14959 0.34 0.34 2 3 2 3 12533 0.29 0.64 2 3 2 3 29372 0.67 0.51 6.3 0.82 3.23 1.10 6.98 0.19 18 LCPE 0.012 47 9.72 463.84 459.27 467.35 35.58 20.13 53 2 1 2 1 2 1972 0.05 0.90 6.3 0.82 3.23 0.13 7.12 0.02 18 LCPE 0.012 101 8.38 459.27 450.81 462.27 33.02 18.69 0 2 1A 1 INLET 1 3063 0.07 0.90 6.3 0.82 3.23 0.20 7.32 0.03 18 LCPE 0.012 28 2.00 450.81 450.25 454.81 16.14 9.13 90 2 CB#601 TO CB#6 601 601 6 601 6723 0.15 0.90 6.3 0.82 3.23 0.45 0.45 0.00 12 LCPE 0.012 24 1.83 470.22 469.78 47322 524 6.67 0 2 CB#401 TO CB#4 401 401 4 401 34479 0.79 0.62 6.3 0.82 3.23 1.58 1.58 0.00 12 LCPE 0.012 24 8.33 469.16 467.16 472.16 11.17 14.22 0 2 CB#302 TO CB#301 302 302 301 302 1880 0.04 0.90 6.3 0.82 3.23 0.13 0.13 0.00 12 LCPE 0.012 47 728 467.80 464.38 470.80 10.44 13.29 0 2 CB#301 TO CB#3 301 301 3 301 14959 0.34 0.66 6.3 0.82 3.23 0.74 0.74 0.00 12 LCPE 0.012 28 1.93 464.38 463.84 467.38 5.37 6.84 0 2 c�)2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 35 Technical Information Report City of Renton BACKWATER COMPUTER PROGRAM FOR PIPES BACKWATER CON.PUTER PrZOGRAA: r OR PI PES Pipe data from file:CB#7 TO VAULT INLE; l.b�� Surcharge condition at intermediate junctions Tailwater Elevation:454.19 feet Discharge Range:1.74 to 7.32 S`ep of C.�,`� [�:-`�� Overflow Elevation:473.9 fee� Weir:NONE Upstream Velocity:0. feet/se:� PIPE NO. 1: 28 LF - 18"CP @ 2.00`� CU�LET: 45G.25 INLEI': 45:1.51 Ii�'IYF: ` JUNC N0. 1: OVERFLOW-EL: 459.81 BEND: 90 DEG DIA/WIDTH: 2.0 Q-RATIO: O.G;' Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HW= *****�*��*�***********�*�**��*�**��************�**,+**�**��*+*�**�***********�,. : 1.74 3.42 454.23 * 0.012 0.50 0.39 3.94 3.94 3.39 3.92 O.E�' 2.21 3.44 454.25 * 0.012 0.57 0.38 3.94 3.94 3.39 3.44 0.?� 2.69 3.46 459.27 * 0.012 0.63 0.42 3.94 3.94 3.40 3.46 0.8E� 3.16 3.49 459.30 * 0.012 0.68 0.46 3.99 3.94 3.40 3.49 0.4- 3.64 3.53 454.39 * 0.012 0.73 0.49 3.94 3.94 3.41 3.53 1.OE� 4.11 3.57 454.38 * 0.012 0.78 0.52 3.94 3.94 3.42 3.57 1.15 4.59 3.62 454.43 * 0.012 0.83 0.55 3.94 3.94 3.93 3.62 1.2< 5.06 3.67 454.48 * 0.012 0.87 0.58 3.94 3.94 3.44 3.67 1.�� 5.54 3.73 454.54 * 0.012 0.91 0.61 3.94 3.94 3.45 3.73 1.4� 6.01 3.79 454.60 * 0.012 0.95 0.64 3.94 3.94 3.46 3.79 1.5= 6.49 3.85 454.66 * 0.012 0.99 0.67 3.94 3.94 3.47 3.85 1.6C E.96 3.93 954.74 F 0.012 i.03 0.69 3.94 3.94 3.48 3.93 1.70 7.44 4.00 454.81 * 0.012 1.06 0.72 3.94 3.94 3.50 4.00 1.79 PI=_ 'd;,. _. 1C1 L= - 1'�� . _ � 8,3= _ ��J,L�I': _- .E- =I�:L�T: 9`_ .�. I'��I�'-=F: � JUNC :'dC. 2: GVEKF�,O'rJ-EL: �C2.�? EEP.D: 0 G3G DIe=./�dI�TH: 2.G Q-RATIG: 0.C� Q(CFS) HW(FT) HW ELEV. * N-FAC D� DN TW DO DE HWO Hk'I *�***�******�**�*��+*�*�*��+�**�******�x*�*****��*��**�********************�_ 1.69 0.60 459.87 * 0.012 0.49 0.24 3.42 3.42 0.49 ***** O.EG 2.15 0.69 459.96 * 0.012 0.56 0.26 3.44 3.44 0.56 ***** O.Eu 2.61 0.77 460.04 * 0.012 0.62 0.29 3.46 3.46 0.62 ***** 0.�, 3.08 0.85 460.12 * 0.012 0.67 0.31 3.49 3.49 0.67 ***** 0.5'� 3.54 0.92 460.19 * 0.012 0.72 0.34 3.53 3.53 0.72 ***** 0.92 4.00 0.98 460.25 * 0.012 0.77 0.36 3.57 3.57 0.77 ***** 0.98 4.46 1.09 460.31 * 0.012 0.62 0.38 3.62 3.62 0.82 ***** 1.G4 4.92 1.10 460.37 * 0.012 0.86 0.40 3.67 3.67 0.86 ***** 1.10 5.39 1.16 460.43 * 0.012 0.90 0.42 3.73 3.73 0.90 ***** l."_E 5.85 1.22 460.49 * 0.012 0.94 0.43 3.79 3.79 0.94 ***** 1.22 6.31 1.27 960.54 * 0.012 0.98 0.45 3.85 3.85 0.98 ***** 1.2I F.?; 1.32 96n.�g - ��.012 _.0- C.�? 3. G3 3.93 l.nl i}*�* 1.32 7.23 1.38 460.65 * 0.012 1.05 0.48 4.00 4.00 1.05 ***** 1.38 F I=_ `],; . �. _ , L= - 1�_ ,._ � _ . � ��J_L�T: ___ .�. L C:T�7. ��;._=1 I I�-]I"i=. _ JUNC NO. 3: OVERFiOW-EL: 467..s5 BEND: 53 DEG DI7�/V�IDTH: �.G Q-RATIO: G.1S� Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **��****�*�*��***+*�*��+�*t++��++******��**�***��,��*�*��*�**�*�*�*�*�*�.. 1.66 0.58 464.42 * 0.012 0.49 0.23 0.60 0.60 0.49 ***** 0.5�� 2.11 0.66 464.50 * 0.012 0.55 0.25 0.69 0.69 0.55 ***** 0.6�: 2.57 0.74 464.58 * 0.012 0.61 0.28 0.77 0.77 0.61 ***** 0.��] rJ2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 36 Technical Information Report City of Renton �.��2 C.81 �c4. 65 � �.012 0.6� 0.3G 0.85 �.�5 0.6; �*x*� �.__ 3.47 0.88 464.72 * 0.012 0.72 0.32 0.92 0.92 0.72 ***** O.E:? 3.93 0.94 464.78 * 0.012 0.76 0.39 0.98 0.98 0.76 ***** 0. 5; 4.38 0.99 464.83 * 0.012 0.81 0.36 1.04 1.04 0.81 ***** 0. 9 : 4.83 1.05 464.89 * 0.012 0.85 0.38 1.10 1.10 0.85 ***** 1.C ; 5.29 1.10 464.99 * 0.012 0.89 0.40 1.16 1.16 0.89 ***** 1."�0 5.74 1.14 464.98 * 0.012 0.93 0.41 1.22 1.22 0.93 ***** 1.19 E.19 1.19 465.03 * 0.012 0.97 0.43 1.27 1.27 0.97 ***** 1.1�+ E.64 1.23 465.07 * 0.012 1.00 0.44 1.32 1.32 1.00 ***** 1.23 7.10 1.27 465.11 * 0.012 1.04 0.46 1.3B 1.38 1.04 ***** 1.27 rI=E NO. 4: 128 LF - 12"CP @ 2.59`a OU�LET: 463.84 INLET: 467.16 INTYP: r �G'dC NO. 4: OVERFLOW-EL: 472.16 BEND: 0 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.9C Q(CFS) HW(FT) HW ELEV. * N-FAC DC D� 1w DO DE HWO HWI *t�**��*�*�*��********+*�**�**��**+**��**��***��*+*��****�*�*****�****�**xt �.40 0.71 467.87 * 0.012 0.51 0.33 0.58 0.58 0.51 ***** 0.71 1.78 0.83 467.99 * 0.012 0.57 0.37 0.66 0.66 0.57 ***** O.E� 2.16 0.94 468.10 * 0.012 0.63 0.41 0.74 0.74 0.63 ***** 0. �9 2.54 1.06 468.22 * 0.012 0.69 0.45 0.81 0.81 0.69 ***** 1.Cn 2.93 1.18 468.34 * 0.012 0.74 0.49 0.88 0.88 0.79 ***** 1.18 3.31 1.33 468.49 * 0.012 0.78 0.52 0.94 0.94 0.78 ***** 1.3s 3.69 1.49 468.65 * 0.012 0.82 0.56 0.99 0.99 0.82 ***** 1.49 4.07 1.67 468.83 * 0.012 0.86 0.60 1.05 1.05 0.86 ***** 1.67 4.45 1.87 469.03 * 0.012 0.89 0.63 1.10 1.10 0.89 ***** 1.87 4.83 2.09 469.25 * 0.012 0.91 0.67 1.14 1.14 0.91 ***** 2.09 5.22 2.32 469.48 * 0.012 0.93 0.71 1.19 1.19 0.93 ***** 2.32 , 5.60 2.58 469.74 * 0.012 0.95 0.75 1.23 1.23 0.95 ***** 2.58 � 5.98 2.85 470.01 * 0.012 0.96 0.79 1.27 1.27 0.96 ***** 2.85 PIPE NO. 5: 192 LF - 12"CP @ 1.00� OUTLET: 467.16 INLET: 469.08 INTYP: 5 JUtvC NO. 5: OVERFLOW-EL: 473.76 BEND: 6 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.09 �iCFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI w.�x***********�***�*****�*��********�*********��***�**��*�*��**�*��*�*�*��**� 0.74 0.48 469.56 * 0.012 0.36 0.30 0.71 0.71 0.36 ***** 0.48 0.94 0.55 469.63 * 0.012 0.41 0.34 0.83 0.83 0.41 ***** 0.55 '_.14 0.61 469.69 * 0.012 0.45 0.38 0.94 0.94 0.45 ***** 0.61 i.34 0.67 469.75 * 0.012 0.49 0.41 1.06 1.06 0.49 ***** 0.67 1.54 0.72 969.80 * 0.012 0.53 0.44 1.18 1.18 0.53 ***** p.72 1.74 0.77 969.85 * 0.012 0.57 0.48 1.33 1.33 0.57 ***** 0.77 1.94 0.82 969.90 * 0.012 0.60 0.51 1.49 1.49 0.60 ***** 0.82 2.14 0.86 969.94 * 0.012 0.63 0.54 1.67 1.67 0.63 ***** 0.86 2.35 0.95 470.03 * 0.012 0.66 0.57 1.87 1.87 0.71 0.95 0.91 2.55 1.06 470.14 * 0.012 0.69 0.60 2.09 2.09 0.94 1.06 0.95 2.75 1.50 470.58 * 0.012 0.72 O.E3 2.32 2.32 1.38 1.50 0.99 2. 95 1.92 471.CG * 0.0=2 0.79 0.66 2.58 '2.58 1.78 _.92 1.04 3.15 2.37 471.45 * 0.012 0.77 0.69 2.85 2.85 2.21 2.37 1.09 c�-P� t��G. 6: , , -F - i�"rc � -.S�i_ CCi�.F'=: 4c�°.U� -P�:L�T: 46��.;� IP�'IyF: . JUNC I�O. 6: OVnRFLOuv-EL: 9is.22 BEND: 0 DEG GiA/wIDTH: 2.G Q-RATIO: 0.71 ;(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI �..�++*�***********�*�**��***�*�*****�*��***��*��*+************�********** r**** 0.71 0.48 470.26 * 0.012 0.36 0.29 0.48 0.48 0.36 ***** 0.48 0.90 0.55 470.33 * 0.012 0.90 0.33 0.55 0.55 0.40 ***** 0.55 , 1.09 0.62 470.90 * 0.012 0.45 0.37 0.61 0.61 0.45 ***** 0.62 1.29 0.68 470.46 * 0.012 0.48 0.40 0.67 0.67 0.48 ***** O.EB 1.48 0.74 470.52 * 0.012 0.52 0.43 0.72 0.72 0.52 ***** 0.7<_ 1.67 0.80 470.58 * 0.012 0.55 0.47 0.77 0.77 0.55 ***** 0.8G C�2015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 37 Technical Information Report City of Renton + o ��*�. �, I'i 1.87 0.86 47�.64 C.012 0.5� G.Su 0.82 O.d2 0.59 v.�o 2.06 0.91 470.69 * 0.012 0.62 0.52 0.86 0.86 0.62 ***** 0.9_ I 2.25 0.97 470.75 * 0.012 0.65 0.55 0.95 0.95 0.65 ***** 0.9? li 2.44 1.03 470.81 * 0.012 0.67 0.58 1.06 1.06 0.67 ***** 1.G3 I, 2.64 1.36 471.14 * 0.012 0.�0 0.61 1.50 1.50 1.13 1.36 1.G� ' 2.83 1.86 471.64 * 0.012 0.`]3 G.64 1.92 1.92 1.59 1.86 1.14 3.02 2.40 472.18 * 0.012 0.75 0.67 2.37 2.37 2.10 2.40 1.21 PIPE NO. 7: 83 LF - 12"CP @ 1.00< OUTLET: 469.78 INLET: 470.61 INTYP: � Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI *�*+******�**�***�*��*�**�*******�*+*��**��+*��*��*��*�*��*�**�*�***�� 0.41 0.36 470.97 * 0.012 0.27 0.23 0.48 0.48 0.27 ***** 0.36 0.53 0.41 471.02 * 0.012 0.31 0.25 0.55 0.55 0.31 ***** 0.41 0.64 0.46 471.07 * 0.012 0.34 0.28 0.62 0.62 0.34 ***** 0.46 0.75 0.50 471.11 * 0.012 0.37 0.30 0.68 0.68 0.37 ***** 0.50 0.86 0.54 471.15 * 0.012 0.39 0.33 0.74 0.74 0.39 ***** 0.54 0.98 0.58 471.19 * 0.012 0.42 0.35 0.80 0.80 0.42 ***** 0.58 1.09 0.62 471.23 * 0.012 0.44 0.37 0.86 0.86 0.44 ***** 0.62 1.20 0.66 471.27 * 0.012 0.47 0.39 0.91 0.91 0.47 ***** 0.66 1.31 0.70 471.31 * 0.012 0.49 0.41 0.97 0.97 0.49 ***** 0.70 1.43 0.73 471.3� * 0.012 0.51 0.43 1.03 1.03 0.51 ***** 0.73 1.54 0.84 471.45 x 0.012 0.53 0.�4 1.36 1.36 0.65 0.84 0.77 1.65 1.29 471.90 - 0.012 0.55 0.�6 1.86 1.86 1.19 1.29 G.81 1.77 1.66 472.47 * 0.012 0.57 0.48 2.40 2.40 1.74 1.86 0.84 BACKWATER CO'•1PUI'ER PRO��vAP7 FOR PIPES Pipe data from file:CB#301 TO CB#3.bwp r h r n i ion at intermediate 'unctions Su c a �e c• 1 t 7 Tailwater Elevation:465.11 feet Discharge Range:0.074 to 0.74 Step of 0.074 [cfs] Overflow Elevation:470.8 feet Weir:NONE Upstream Velocity:0. feet/sec PIPE N0. 1: 28 LF - 12"CP @ 1.93`s OUTLET: 463.84 INLE^: 469.38 INTYP: 5 Q(CFS) HW(FT) HG1 ELEV. * N-FAC DC DN TW DO DE HWO HWI x*+*��*��*�*�*��**x*******�********�****+**��*+��**�*��***+�*�**�** 0.07 0.74 465.12 * 0.012 0.12 0.09 1.27 1.27 0.74 0.74 0.14 0.15 0.74 465.12 * 0.012 0.16 0.12 1.27 1.27 0.74 0.74 0.20 0.22 0.74 465.12 * 0.012 0.20 0.14 1.27 1.27 0.74 0.74 0.25 0.30 0.75 465.13 * 0.012 0.23 0.16 1.27 1.27 0.74 0.75 0.29 0.37 0.75 465.13 * 0.012 0.26 0.18 1.27 1.27 0.74 0.75 0.33 0.44 0.�5 465.13 * 0.012 0.28 0.20 1.27 1.27 0.74 0.75 0.3? 0.52 0.76 965.14 * 0.012 0.30 0.21 1.27 1.27 0.74 0.76 0.40 0.59 0.76 965.14 * 0.012 0.32 0.23 1.27 1.27 0.74 0.76 0.43 0.67 0.77 465.i5 * 0.012 0.35 0.24 1.27 1.27 0.74 0.�7 0.46 0.74 0.77 465.15 * 0.012 0.36 0.26 1.27 1.27 0.74 0.77 0.49 BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:CB€302 TO CB#301.b�Jip ' Surcharge condition at intermediate junctions � Tailwater Elevation:465.15 feet i Discharge Range:0.013 to 0. 13 Sr�=� c- 0.0-=; [�fs] Overflow Elevatica:470.8 feet I We i r:TdCNE Ct��r�ar,- , �lo�-- 0. `c��_ . ,:_� "2015 D. R. STRONG Consultina Engineers Inc. Maertins Ranch Page 38 Technical Information Report City of Renton I PIPE NO. 1: 47 LF - 12"CP @ 7.28o OUTLET: 464.38 INLET: 467.80 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI �*�**��***�************��**�***�*********�****��****��*��*�*��*�*�**��*� 0.01 0.05 467.85 * 0.012 0.05 0.03 0.77 0.77 0.05 ***** 0.03 0.03 0.07 467.87 * 0.012 0.07 0.04 0.77 0.77 0.07 ***** 0.05 0.04 0.09 467.89 * 0.012 0.09 0.05 0.77 0.77 0.09 ***** 0.07 0.05 0.10 467.90 * 0.012 0.10 0.06 0.77 0.77 0.10 ***** 0.09 0.06 0.11 467.91 * 0.012 0.11 0.06 0.�7 0.77 0.11 ***** 0.10 0.08 0.12 467.92 * 0.012 0.12 0.07 0.77 0.77 0.12 ***** 0.12 0.09 0.13 467.93 * 0.012 0.13 0.07 0.77 0.77 0.13 ***** 0.13 �I 0.10 0.14 967.94 * 0.012 0.14 0.08 0.77 0.77 0.14 ***** 0.14 ; 0.12 0.15 967.95 * 0.012 0.1� 0.08 0.77 0.77 0.14 ***** 0.15 i 0.13 0.16 967.56 F 0.012 0.15 0.08 0.77 0.77 0.15 ***** 0.16 I 0.13 0.16 467.96 * 0.012 0.15 0.08 0.77 0.77 0.15 ***** 0.16 I BACKWATER COMPUTER PROGRAM FOR PIPES I Pipe data from file:CB#401 TO CB#4.bwp j Surcharge condition at intermediate junctions Tailwater Elevation:970.01 feet Discharge Range:0.158 to 1.58 Step of 0.158 [cfs] Overflow Elevation:472.16 feet heir:NONE Upstream Velocity:0. feet/sec PIPE N0. 1: 24 LF - 12"CP @ 8.33`s OUTLET: 467.16 INLET: 969.16 INTYP: 5 I� Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI *�*******��*��*+*��****�*��**********��***********�*************�*****�***+ 0.16 0.86 470.02 * 0.012 0.17 0.09 2.85 2.85 0.86 0.86 0.18 0.32 0.86 470.02 * 0.012 0.24 0.12 2.85 2.85 0.86 0.86 0.27 0.47 0.87 470.03 * 0.012 0.29 0.15 2.85 2.85 0.86 0.87 0.35 0.63 0.88 470.04 * 0.012 0.34 0.17 2.85 2.85 0.86 0.88 0.42 0.79 0.89 470.05 * 0.012 0.38 0.19 2.85 2.85 0.86 0.89 0.4E 0.95 0.90 470.06 * 0.012 0.41 0.20 2.85 2.85 0.86 0.90 0.5� 1.11 0.92 470.08 * 0.012 0.45 0.22 2.85 2.85 0.87 0.92 0.59 1.26 0.94 470.10 * 0.012 0.48 0.23 2.85 2.85 0.87 0.94 0.64 1.42 0.97 470.13 * 0.012 0.51 0.25 2.85 2.85 0.88 0.97 0.69 1.58 0.99 470.15 * 0.012 0.54 0.26 2.B5 2.85 0.88 0.99 0.75 BACK.G]i-�T�R COMPUTER PROGRAM FOR PIPES Pipe data from file:CB€601 TO CB#6.bwp Surcharge condition at intermediate junctions Tailwater Elevation:472.1B feet Discharge Range:0.045 to 0.45 Step of 0.045 [cfs] Overflow Elevation:473.22 feet Weir:NCN� Ups�ream Velocity:0. feet/sec PIPE NO. 1: 24 LF - 12"CP @ 1.83� OUTLET: 969.78 INLET: 470.22 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ********�**�+��*�*��+��*�*��+*****�*��***********�*�*�**************�**** 0.05 1.97 472.19 * 0.012 0.09 0.07 2.40 2.40 1.97 1.97 0.11 0.09 1.96 472.18 * 0.012 0.13 0.10 2.40 2.40 1.96 1.96 0.16 0.14 1.°6 472.18 * 0.012 0.16 0.12 2.40 2.40 1.96 1.96 0.19 0.18 1.96 472.18 * 0.012 0.18 0.13 2.40 2.40 1.96 1.96 0.23 0.23 1.96 472.18 * 0.012 0.20 0.15 2.�0 2.40 1.96 1.96 0.25 02015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 39 Technical Information Report City of Renton 0.27 L°6 472.18 * O.Oi2 0.22 0.16 2.40 2.40 1.96 1.96 0.2E 0.31 1.97 472.19 * 0.012 0.24 0.17 2.40 2.40 1.96 1.97 0.?1 0.36 1.97 472.19 * 0.012 0.25 0.18 2.40 2.40 1.96 1.97 0.3_; 0.�1 1.9? 4?2.-9 * Q.C12 0.27 0.19 2.90 2.40 1. 9E 1.9� 0.��. 0.45 1.97 972.19 * 0.012 0.28 0.20 2.40 2.40 1.96 1.97 0.37 = 2015 D R STRONG Consulting En�ineers Inc Maertins Ranch Page 40 TechnicGl Information Report City of Renton SECTION VI SPECIAL REPORTS AND STUDIES The following report and studies have been provided with this submittal. 1. Critical Areas Report — October 24, 2014 2. Traffic Impact Analysis —TraffEx, Inc., October 27, 2014 3. Geotechnical Engineering Study— Earth Solutions NW LLC, October 29, 2014 4. Arborist Report — GreenForest, Inc., November 12, 2014 5. School Walkway Analysis — November 6, 2014 6. May Creek Basin Plan — (Not Included) i 02015 D. R.STRONG Consulting Engineers Inc. 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'_ .y�t '- GEOTECHNICAL ENGINEERING STUDY�, - ��: MAERTINS RANCH ``�`4 RESIDENTIAL DEVELOPMENT t� 1508 ILWACO AVENUE NORTHEAST �`��= RENTON, WASHINGTON ,,.�,k'�`- � `=�;�` �.*-: . r� � ES-3626 =�� : r� , , ��;'�:�-:� .�.. ��:r '�- ��.�, Y`'� � ��.�'��:"_ __ � T r , . , - . �`�. &'S �,.; :1�',"qr t`',--.,��yl `.� ��#.A.7� 4.1; T � -- _.t: . r � :Z� � =�. a ,� +(�g �' c� �-,, � �� { .� : , _ � _ _ . :� � 180� -��'��r��x._i�,��S� ' ._,-,_�e�le�2t .�� ; �':�„ -r_' „�:- } . _ � � %d ` -�,.�., ;_. �-a-��-�-�� .,�.(�'�,1:��}�T-��:�� '��,..,r� „�_,� ��,,,� � �� ,,�.- � , � • �,,, ; ; �-� `;� �< •:�`V��:'��c� ��+�Qll�ll,�clui��''= �`-��.�-e`� i .��. � �� 'l��+ = p ` - • �, � '' �� `� . �, _�� ''"' \�+ ti'' �y� �' �. . a . _ �' } 4c� i� i4� S`# € .r��,'.y't�t t �_i�',r��S��' ��-_.,. �c��.�� i('�� .�Ti.t� -. •4'_��art_-af�.�.�1`�4i� �..�./..'._�J� : _ . { iv%-'� 'Y.'�.__� r � "' __ PREPARED FOR PNW Holdings, LLC October 29, 2014 ��_ __� � ______ Stephen H. Avrii Staff Geologist C ,�� R. A ��- a�wns j�,�cn� rt�' ,�L. Cr, � /.� .;�{, C? h � � � � `��3!�tFR�� l�or�rn�.��'� ,�,��,H � Kyle R. Campbell, P.E. Principal GEOTECHNICAL ENGINEERING STUDY MAERTINS RANCH RESIDENTIAL DEVELOPMENT j 1508 ILWACO AVENUE NORTHEAST '� RENTON, WASHlNGTON ES-3626 Earth Solutions NW, LLC 1805 - 136t" Place Northeast, Suite 201 Beflevue, Washington 98005 Phone: 425-449-4704 Fax: 425-449-4717 Toll Free: 866-336-8710 II � I � I ' ll I . . . eo ec nica n ineerin e or . . , ,, • . . . , , . - , , , ,- . , , • . . „ , - • � t i � . � � i i'� i - � i . .�• i 6eotechnical3ervices Are Perfnrmed for • elevation,contiguration,location,orientation,or weight of the 3pecitic Purposes, Persons, and Projects proposed sfructure, Geotechnical engineers structure their services ta meeE the specific needs of • composition of the design team,or their clients.A geotechnical engineering study conducted(or a civil engi- • project ownership. neer may not fulfill the needs of a construction contractor or even another civil engineer.8ecause each geotechnical engineering study is unique,each As a general rule,always inform your geotechnical engineer of project geotechnical engineering report is unique,prepared solelyfor the client.No changes�ven minor ones—and request an assessment of their impact. one except you should rely on your geotechnical engineering report without Geotechnical engineers cannotacceptresponsibrlity orlrabilityforproblems first conferring with the geotechnical engineer who prepared it.And no one thar occur because their reports do no[consider developments of which , —nof evenyou—shoufd app[y the report for any purpose or project they were notinformed exc°pt the ane originally contemplated. 3ubsur�ace Condi�ons Can Change Read the full Report A geotechnicaf engineering report is based on conditions that existed at Serious problems have occurred because those relying on a geotechrtical the time the study�rras performed.Do not rely on a geotechnical engrneer- � engineering report did not read it ail.Do not rely on an executive summary. ing repo�twhose adequacy may have been afiected by:the passage of Do not read selected elements only. time;by man-made events,such as construction on or adjacent to the site; ar by natural events,such as floods,earthq�akes,or groundwater fluctua- A 6eotechnieal Engineering Re ort Is Based an tions.Always contact the geotechnical engineer before applying the report A Unique Set of Project-Sp4�C F'dCt01'S to determine if it is still reliable.A minor amount of additional testing or Geotechnical ertgineer;consitler a number of unique,project-specific fac- analysis could prevent major problems. tors when establishing the scope of a study.Typical factors include:the client's goals,abjectives,and risk management preferences;the general Most 6eoteehnical Fndings Are Professional nature of the structure involved,its size,and canfiguration;the location of OpIR10tIS the structure on the site;and other planned or existing site improvements, Site exploration iden#ifies subsurface conditions only at those points where ( such as access roads,parking lots,and underground utilities.Unless the subsurface tests are conducted or sarnples are taken.Geotechnical engi- geotechnical eng9neer who conducted the study specifically indicates oth- neers review#ield and laboratory data and then apply their professional ' erwise,do not rely on a geotechnical engineering repart that was: judgment to render an opinian about subsurface conditions thraughout the • nat prepared for you, site.Actual subsurface conditions may diffe�—sometimes significantly— • not pregared for your project, from those indicated in your report.Retaining the geotechnical engineer • not prepared for the specific site explored,or who developed your report to provide construction observation is the • completed before important project changes were made. most effective method of managing the risks associated with unanticipated conditions. Typical changes that can erode the reliabiliry of an existing geotechnica! engineering report include those that affect: A R8p01'�'s Reeommendaiions Are Nat�nal • the function of the proposed structure,as when iYs changed from a Do not overrely on the construction recommendations included in your parking garage to an office building,or from a light industrial plant report. Those recommendafrons are notfinal,because geotechnical engi- to a refrigerated warehouse, neers develop them principally from judgment and opinion.Geotechnical engineers can finalize their recommendations only by observing actuai subsurface conditions revealed during construction. The geotechnical have led to disappointments,claims,and disputes.To help reduce the risk engineer who developed yourreport cannotassume resporrsibility or of such outcomes,geotechnical engineers commonly include a variety of liabilityfor tf►e report's recommendations if that engineer does not perform explanatory provisions in their repo�ts.Sometimes labeled"limitations° consfruction observation. many of these provisions indicate where geotechnical engineers'responsi- bilities begin and end,to help others recognize their own responsibiiities A 6eotechnical Engineering Report ls Subject to and risks.Read these provisions closely.Ask questions.Your geotechnical Misinterpretation engineer should respond f�lly and frankly. Other design team members'misinterpretation of geotechnical engineering reports h2s resulted in costly problems.Lower that risk by having your gea- �eoenvironmentai Concerns Are Not Covered technical engineer confer with appropriate members of the design team after The equ+pment,techniques,and personne�used tc perform a geoenviron- submitting the report.Also retain your geotechnical engineer to review perti- mentalstudy differ significantly from those used to perform a geotechnical nent elernents of the design team's plans and specifications.Contractors can study.For that reason,a geotechnical engineering report does not usualiy also misinterpret a geotechnical engineerir�g report. Reduce that risk by reiate any geoenvironmental findings,conclusions,or recommendations; having your geotechnical engineer participate in prebid and preconstruc6on e.g.,about the likelihood of encountering underground storage tanks or I conierences,and by providing construction observation. regulated cantaminants. Unanticipated environmental problems haveled to numerous project failures.If you have not yet obtained your own geoen- Do Not Redraw the Engineer�S LOgS vironmenta{information,ask your geotechnical consultant for risk rrbn- � Geotechnical engineers prepare final boring and testing logs based upon agement guidance.Do not rely on an environmental report prepared for their interpretation of field logs and laboratory data.To prevent errors or someone else. omissions,the iogs included in a geotechnical engineering report shoufd ne��erbe redrawn for inclusion in architectural or other design drawings. Ohta� Professional Assistanee Ta Deal with Mold Only photographic or electronic reproduction is acceptable,bu[recognize Diverse strategies can be applied during Cuilding design,construcfion, that separatrng logs from the report can elevate risk. operation,and maintenance to prevent significant amounts of mold from grovring on indoor surfaces.To be effective,all such strategies should be 6ive Contractors a Complete Report and devi�ed for the express purpose of mold prevention,integrated into a com- �illldBflCe prehen�ive plan,and exec�ted with diligent over5ight by a professional Some awners and design professionals mistakenly believe they can make mold prevention consult2nt.Because just a small amount of water or contractors liable for unanticipated subsurface conditions by limiting what moisture can lead to the development of severe mold infestations,a num- , they provide for bid preparation.To help prevent costly problems,give con- ber of mold prevention strategies focus on keeping building surfaces dry. � tractors the complete geotechnical engineerng report,butpreface it with a While groundwater,water infiltration,and similar issues may have been ' clearly written letter of transmittal.In that letter,advise contractors that the addressed as paR of the geotechnical engineering study whose findings report was nat prepared for purposes of bid development and that the are conveyed i�rt�is repo�t,the geotechnical engineer in charge of this report's accuracy is limited;encourage them to confer with the geotechnical project is not a mold prevention consultant;none of fhe services per- engineer who prepared the report(a modest fee may be required)and/or to formed in connection with the geotechsical engineer's study conduct additio�al study to obtain the specific iypes af information they were designed or candr�cted for the purpose of mold preven- need or prefer.A prebid conference can also be valuable. Be sure conhac- tion. Proper implemenfation of the recommendations conveyed tors have sufficient time to perform additional study.Only then might you in this reperf will not of itself be sufficient fo prevent mold from be in a position to give contractors the best information available to you, growing in nr on the shucf�re involved. while requiring them to at least share some of th�e financral responsibilities stemming from unanticipated conditions. RCI�1, on Your ASFE-Member 6eotechncial Engmeer for Additional Assistance Read Responsibility Provisions Closely Prlembersh+p in ASFE/The Best People on Earth exposes geotechnical Some clients,design professionals,and contractors do not recognize that engineers to a wide array of risk management techniques that can be of geotechnical engineering is far less e�ct than other engineering disci- genuine benefit for everyone invofved with a construction project.Confer plines.This lack of understanding has created unrealistic expectations that with you ASFE-member geotechnical engineer for mare information. ASFE �ss �est ��e1e •■ E�rtA 88i1 Colesville Road/Suite G106,Silver Sperg '.1 _� Telephore:301/565-2733 Facsimile:301/�.. �� ' e-mail:info�asfe.org www.asfe.orc Copyright 2004 by ASFE,lnc.Duplication,ieproduction,or copying oi thrs documenf,!n whole or in part b, � ,;:.__. , . -�_ specific wntten permissior+.Fxceiptiny,quoting,or othernise extracting wording from this dacument is permi[ted onty with the express wnren permiss;or o�ASFE,and o��;��: purposes ol scholarly research or book review.Only members of ASFEmay use this document as a complemerrt to or as an elemenf o(a geotechnica/engineering reporf.A��y ot�e� f�im,individual,or other entrty that so uses this documertt without being an ASFf inember could be committing rregligent ar intentional(fraudulent}misrepresentatiort. IIGER06045.OM v i � October 29, 2014 ES-3626 Earth Solutions NW LLC • Geotechnical Engineering • Construdion Monitoring • Environmental Sciences PNW Holdings, LLC 9675 - 36th Street, Suite 105 Mercer Island, Washington 98040 Attention: Mr. Justin Lagers Dear Mr. Lagers: Earth Solutions NW, LLC (ESNW) is pleased to present this report titled "Geotechnical Engineering Study, Maertins Ranch, Residential Development, 1508 Ilwaco Avenue Northeast, Renton, Washington". In general, the site is underlain by a weathered soil zone grading to very dense gfacial tilE deposits. In our opinion, the proposed residential buildings can be supported on conventional continuous and spread footing foundations bearing on competent native soils, re-compacted native soils, or structural fill. Competent soils suitable for support of foundations should be encountered at depths of befinreen one to two feet below existing grades at most locations. Where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of the soils to the specifications of structural fill, or overexcavatian and replacement with a suitable structural fill material will be necessary. Groundwater seepage was not observed at the test pit locations. However, perched groundwater seepage should be expected during grading activities, particularly during winter, , spring and early summer months. Recommendations for foundation design, site preparation, drainage, and other pertinent recommendations are provided in this study. We appreciate the opportunity to be of service to you on this project. If you have questions regarding the content of this geotechnical engineering study, please call. Sincerely, EARTH SOLUTIONS NW, LLC ,�.��' - _-.:--� .�---- _� _ �-- - Stephen H. Avril Staff Geologist 1805 -1361h Place N.E.,Suite 201 • Bellewc, Lti'A 98005 • (425)449-4704 • FAX 1425)449-4711 Table of Contents ES-3626 PAGE INTRODUCTION ................................................................... 1 General ............................................................._._._.... 1 Proiect Description. ..................................................... 1 SITE CONDITIONS.................................................................. 2 Surface........................................................................ 2 Subsurface. ................................................................. 2 Fill..................................................................... 2 Topsoil.... .......................................................... 2 NativeSoil .......................................................... 3 Geologic Setting.................................................. 3 Groundwater. ............................................................... 3 DISCUSSION AND RECOMMENDATIONS.................................. 4 Generaf. .........................................................,............ 4 Site Preqaration and General Earthwork........................... 4 Wet Season Grading............................................. 5 In-situ Soils.................................................................... 5 ImportedSoils................................ .............................. 6 Structural Fill......................................... ..............,..... 6 Foundations ............................................................... 6 Seismic Desiqn Considerations...................................... 7 Slab-On-Grade Floors. ........................... .................... 7 Retaininq Walls............................................................ 7 DrainaAe ................................................................................... 8 Preliminary Storm Vault Design.................................. 8 Infiltration Feasibility.................................................... 9 Excavations and Slopes. ..........................,.....,...................,... 10 Pavement Sections ...................................................... 10 LIMITATIONS. ................................................. .................... 11 Additianal Services....................................................... 11 Earth Solutions NW,LLC Table of Contents Cont'd ES-3626 GRAPHICS Plate 1 Vicinity Map Plate 2 Test Pit Location Plan Plate 3 Retaining Wafl Drainage Detail Plate 4 Footing Drain Detail APPENDICES Appendix A Subsurface Exploration Test Pit Logs Appendix B Laboratory Testing Results Earth Solutions NW,LLC GEOTECHNICAL ENGINEERING STUDY MAERTINS RANCH RESIDENTIAL DEVELOPMENT 1508 ILWACO AVENUE NORTHEAST RENTON, WASHINGTON ES-3626 iNTRODUCTION General This geotechnical engineering study was prepared for the proposed residential development to be constructed on the east side of the cul-de-sac at the terminus of Ilwaco Avenue Northeast, and south of the intersection with Northeast 16th Street in Renton, Washington. A large portion of the site is occupied by horse pastures. The purpose of this study was to explore subsurface conditions across the site and develop gec�technical recommendations for the proposed development. Our scope of services for completing this geotechnical engineering study included the following: • Excavation, logging and sampling of five test pits on the site; • Laboratory testing of soil samples obtained from the test pits; , • Engineering analyses, and; I � Preparation of this report, The following documents/maps were reviewed as part of our report preparation: • Preliminary subdivision layout for Maertin Ranch, Sheet SP1, dated October 14, 2014, provided by D.R. Strong Consulting Engineers; • Geologic Map of Washington, Northwest Quadrant, Dragovich, Logan, et al, 2002, and; • Washington State USDA Soil Conservation Survey (SCS). Proiect Description We understand the site will be developed with 13 residential lots, associated improvements access roads, and a drainage tract located within the no�theast portion of the site. The drainage tract is to consist of a stormwater detention vault. The remainder of the site will be developed with general landscaping and paved driveways. The site topography generally descends from west towards the east. Given the topographic change across the site, we anticipate grading activities will likely invofve cuts and fills on the order of ten feet or less to establish the final design grades. PNW Holdings, LLC ES-3626 October 29, 2014 Page 2 Building construction is anticipated to consist of relatively lightly loaded wood framing and sfab- on-grade floors. Perimeter foundation loading is expected to range from approximately 1 to 2 kips per foot. Slab-on-grade loading is expected to be on the order of 150 psf. If the above design assumptions are incorrect or change, ESNW should be contacted to review the recommendations in this report. ESNW should review the final design to confirm that the geotechnical recommendations included in this report have been incorporated into the project plans. SITE CONDITIONS Surface The site is located on the east side of the cul-de-sac at the terminus of Ilwaco Avenue Northeast, south af the intersection with Northeast 16�h Street in Renton, Washington. The approximate location of the property is illustrated on Plate 1 (Vicinity Map) included in this study. The site is irregular in shape and consists of a single residential parcel. The site is currently developed with single-family residence and outbuilclings. The majority, however, of each parcel is occupied by green space. The existing site topvgraphy descends from the north towards the east, with elevation change on the order of 20 feet. Vegetation on the subject site consisted primarily of field grass, cedar and fir trees during our fieldwork (October 20, 2014). Subsurface An ESNW representative observed, logged and sampled five test pits excavated with a trackhoe and operator provided by the client across the accessible portions of the site. The approximate locations of #he test pits are depicted on the Test Pit Location Plan (Plate 2}, Please refer to the test pit logs provided in Appendix A for a more detailed description of the subsurFace conditions. Topsoil . Topsoil was encountered at all test pit locations ranging in thickness of three to eight inches below existing grade. Topsoil is not suitable for use as structural fill nor should it be mixed with material to be used as structural fill. Topsoil or otherwise unsuitable material can be used in landscaping areas if desired. Fill Fi11 was encountered at test pit location TP-2. The fill was observed to consist of re-worked native soil; and was located in the east po�tion of the subject site. The fill tn�as observed extending from the existing surf�cE e'evation to a depth of �E}proxir»ately tr,°�o feet PNW Holdings, LLC ES-3626 October 29, 2014 Page 3 There is the potential for limited amounts of fill surrounding the existing residential structure; and along road alignments and existing utility trenches. If fill is encountered it may be suitable for support of foundations; however a representative of ESNW should be retained during the construction phases of the site development to evaluate the suitability of any on-site soils for support of foundations. Native Soil Underlying the topsail and isolated fill soil, native soils consisting primarily of inedium dense weathered glacial deposits transitioning ta very dense unweathered glacial till were encountered extending to the maximum exploration depth of eight feet below existing grades. The glacial till soil consisted of sifty sand with gravel (Unified Soil Classification, SM); and soil relative density generally increased in depth, from medium dense in the weathered zone to very dense within the unweathered glacial till. The weathered glacial till was generally observed extending to an average depth of between finro to three feet; where it transitioned to an unweathered very dense condition. Geologic Setting The referenced geologic map resource identifies glacial till (Qgt) deposits across the site and surrounding areas. The referenced SCS soil survey identifies Alderwood gravelly sandy loam series soils across the entirety of the site. Alderwood soils are typified by glacial drift and/or outwash and typically present a slight to moderate erosion hazard and slow to medium runoff. ESNW did not observe the presence of glacia! outwash in any of the test Iocations; but the presence of gravelly sandy loam was observed at all of the test pit locations. The soil conditions observed at the test pit locations are generally consistent with glacial till I deposits described by the geologic maps for the area. Groun�lwa�er Groundwater was not observed in the test pits during the fieldwork (October 2014). However, based on our experience, groundwater seepage on till sites will typically be perched at variable depths within the substrata of glacial till soil near the contact between weathered and unweathered material; therefore, seepage should be expected in all grading activities at this site, particularly during the winter, spring and early summer months. Groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. In general, groundwater flow rates are higher during the wetter, winter months. Earth Solutions fJIN,LLC PNW Holdings, LLC ES-3626 October 29, 2014 Page 4 DISCUSSION AND RECOMMENDATIONS General In our opinion, construction of the proposed residential development is feasible from a geotechnical standpoint. The proposed residential buildings can be supported on conventional continuous and spread footing foundations bearing on competent native soils, re-compacted native soils, or structural fill. Slab-on-grade floors should be supported on dense native sail or struc#ural fill. Competent soils suitable for support of foundations should be encountered at depths of between one to two feet below existing grades. Where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of the soils to the specifications of structura! fill, or overexcavation and replacement with a suitable structural fill material will be necessary. Recommendations for foundation design, site preparation, drainage, and other pertinent geotechnical recommendations are provided in the following sections of this study. This study has been prepared for the exclusive use of PNW Holdings, LLC and their representatives. No warranty, expressed or implied, is made. This study has been prepared in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. Site Preparation and Earthwork Si#e preparation activities will involve removal of existing structures, site clearing and stripping, � and implementation of temporary erosion control measures. The primary geotechnical I considerations associated with site preparation activities include building pad subgrade ' preparation, stormwater vault construction, underground utility installations, and preparation of pavement subgrade areas. �i Temporary construction entrances and drive lanes, consisting of at least 12 inches of quarry spalls can be considered in order to minimize off-site soil tracking and to provide a stable access entrance surface. Erosion cantrol measures should consist of silt fencing placed along the down gradient side of the site. Soil stockpiles should be covered or otherwise protected to reduce soil erosion. Temporary sedimentation ponds or other approaches for controlling surface water runoff should be in place prior to beginning earthwork activities. Topsoil and organic-rich soil was encountered generally within the upper three to eight inches at the test pit locations. Topsoil and organic-rich soil is not suitable for foundation support, nor is it suitable for use as structural fill. Topsoil or organic-rich soil can be used in non-structural areas if desired. Over-stripping of the site, however, should be avaided. A representative of ESNW should observe the initial stripping operations, to provide recommendations for stripping depths based on the soil conditions exposed during stripping. ' Earth Solutions MN,LLC PNW Holdings, L�C ES-3626 October 29, 2014 Page 5 Subgrade conditions expected to be exposed throughout the proposed building and pavement , areas will likely be comprised of silty sand deposits. After the compfetion of site stripping and rough grading activities ESNW recommends a proofroll utilizing a fully loaded solo dump truck in order to determine the suitability of the exposed native soils for support of foundations and roadways. ESNW should be retained during this phase of earthwork to observe the proofroll and other earthwork activities. The soils exposed throughout subgrade areas should be compacted to structural fill specifications prior to constructing the foundation, slab, and pavement elements. The subgrade throughout pavement areas should be compacted as necessary and exhibit a firm and unyielding condition when subjected to the proofrolling with a loaded solo dump truck. Structural fill soils placed throughout foundation, slab, and pavement areas should be placed over a firm base. Loose or otherwise unsuitable areas of native soil exposed at subgrade elevations should be compacted to structural fill requirements or overexcavated and replaced with a suitable structural fill material. Where structural fill soils are used to construct foundation subgrade areas, the soil should be compacted to the requirements of structural fill described in the following section. Foundation subgrade areas should be protected from disturbance, construction traffic, and excessive moisture. Where instability develops below structural fill areas, use of a woven geotextile below the structural fill areas may be required. A representative of ESNW should observe structural fill placement in foundation, slab, and pavement areas. Wet Season Grading Perched groundwater may be present near the contact between the weathered soil and the underlying unweathered glacial till soil. This condition coupled with the moderate to high moisture sensitivity of the soil will make grading during periods of rain difficult. Mass grading should take place during the late summer months when conditions are more favorable. If grading takes place during the wetter winter or spring months, a contingency in the project budget should be included to allow for export of native soil and import of structural fill as described below, or treatment of the on-site soil with cement. In-situ Soils The soils encountered throughout the majority of the test sites have a moderate sensitivity to moisture and were generally in a moist condition at the time of the exploration (October 2014). In this respect, the in-situ soils may not be suitable for use as structural fill if the soil moisture content is more than 2 to 3 percent above the optimum level at the time of construction. In general, soils encountered during the site excavations that are excessively over the optimum moisture content will require moisture conditioning prior to placement and compaction. Conversely, soils that are below the optimum moisture content will require moisture conditioning through the addition of water prior to use as structural fill. If the in-situ soils are determined to not be suitable for use as structural fill, then use of a suitable imported soil may be necessary. Earth Solutions NW,LLC PNW Holdings, LLC ES-3626 October 29, 2014 Page 6 Imported Soils Imported soil intended for use as structural fi(I should consist of a well graded granular soil with a moisture content that is at or near the optimum level. During wet weather conditions, imported soil intended for use as structural fill should consist of a well graded granular soil with a fines content of 5 percent or less defined as the percent passing the#200 sieve, based on the minus three-quarter inch fraction. Structural Fill Structural fill is defined as compacted soil placed in foundation, slab-on-grade, and roadway areas. Fills placed to construct permanent slopes and throughout retaining wall and utility trench backfill areas are also considered structural fill. Soils placed in structuraE areas shoufd be placed in loose lifts of 12 inches or less and compacted to a relative compaction of 90 percent, based on the laboratory maximum dry density as determined by the Modified Proctor Method (ASTM D-1557). Soil placed in utility trenches, pavement areas and in the upper 12 inches of slab-on-grade areas should be compacted to a relative compaction of at least 95 percent. Additionally, more stringent compaction specifications may be required for utility trench backfill zones, depending on the responsible utility district or jurisdiction. Foundations Based on the results of our study, the proposed residential structures can be supported on , conventional spread and continuous footings bearing on competent native soils, re-compacted native soils, or structural fill. Based on the soil conditions encountered at the test pit locations, competent native soils suitable for support of foundations should be encountered at depths of between one to two feet below existing grades. Where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of the soils to the specifications of structural fill, or overexcavation and replacement with structural fill, may be necessary. i Provided foundations will be supported as described above, the following parameters can be used for design of new foundations: • Allowable soil bearing capacity 2,500 psf I�I • Passive earth pressure 300 pcf(equivalent fluid) ' • Coe�cient of friction 0.40 A one-third increase in the allowable soil bearing capacity can be assumed for short-term wind and seismic loading conditions. The above passive pressure and friction vafues include a factor-of-safety of 1.5. With structural loading as expected, total settlement in the range of ane inch and differential settlement ofi about one-half inch is anticipated. The majority of the settlements should occur during construction, as dead loads are applied. Earth Solutions NW,LLC PNW Holdings, LLC ES-3626 October 29, 2014 Page 7 Seismic Desiqn Considerations The 2012 IBC recognizes the American Society of Civil Engineers (ASCE) for seismic site class definitions. In accordance with Table 20.1-1 of the ASCE Minimum Design Loads for Buildings and Other Structures manual, Site Class D should be used for design. The referenced liquefaction susceptibility map indicates the site and surrounding areas main#ain very low liquefaction susceptibility. Liquefaction is a phenomenon where saturated or loose soils suddenly lose internal strength in response to increased pore water pressures resulting from an earthquake or other intense ground shaking. In our opinion, site susceptibility to liquefaction can be characterized as negligible. The relative density of the native soil, is the primary basis for this characterization. Slab-On-Grade Floors Slab-on-grade floors for residential buildings constructed at this site should be supported on a firm and uny'telding subgrade. Where feasible, the existing native soils exposed at the slab-on- grade subgrade level can be compacted in place to the specifications of structural fill. Unstable or yielding areas of the subgrade should be recompacted or overexcavated and replaced with suitable structural fill prior to construction of the slab. A capillary break consisting of a minimum of four inches of free draining crushed rock or gravel should be placed below the slab. The free draining material should have a fines content of 5 percent or less (percent passing the #200 sieve, based on the minus three-quarter inch fraction). In areas where slab moisture is i undesirable, installation of a vapor barrier below the slab should be considered. If a vapor barrier is to be utilized it shouid be a material specifically designed for use as a vapor barrier and should be installed in accordance with the manufacturer's specifications. 'I Retaininq Walls ' Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The following parameters can be used for retaining wall design: • Active earth pressure (yielding condition} 35 pcf (equivalent fluid) • At-rest earth pressure {restrained condition) 55 pcf • Traffic surcharge for passenger vehicles 70 psf (rectangular distribution} (where applicable) • Passive resistance 300 pcf (equivalent fluid) • Coefficient of friction 0.40 • Seismic surcharge (active condition) 6H* • Seismic surcharge (restrained condition) 11 H* "where H equals retained height Earth Solutions NW,LLC PNW Holdings, LLC ES-3626 October 29, 2014 Page 8 Additiona! surcharge loading from adjacent foundations, sloped backfill, or other loads should be included in the retaining wall design. Drainage should be provided behind retaining walls such that hydrostatic pressures do not develop. If drainage is not provided, hydrostatic pressures should be included in the wall design. Retaining walls should be backfilled with free draining material that extends along the height of the wall, and a distance of at least 18 inches behind the wall. The upper one foot of the wall backfill can consist of a less permeable soil, if desired. A perforated drain pipe should be placed along the base of the wall, and connected to an approved discharge location. A typical retaining wall drainage detail is provided on Plate 3, Drainaqe Groundwater was not observed during the fieldwork (Octaber 2014). However, minor perched groundwater should be anticipated in site excavations. Temporary measures to control surface water runoff and groundwater during construction would likely involve interceptor trenches and sumps. ESNW should be consulted during preliminary grading to identify areas of seepage and to provide recommendations to reduce the potential for instability related to seepage effects. Final surface grades should slope away from structures at a gradient of at least 2 percent for a distance of ten feet. ln our opinion, foundation drains should be installed along building perimeter footings. A typical foundation drain detail is provided as Plate 4. Preliminary Storm Vault Design Vault foundations shoufd be supported on competent native soil or crushed rock placed directly on competent native soil. Fina! storm vault designs must incorporate adequate buffer space from property boundaries such that temporary excavations to construct the vault struc#ure can be successfuNy completed. Perimeter drains should be installed around the vault and conveyed to an approved discharge point. The presence of perched groundwater seepage should be anticipated during excavation activities for the vault. Earth Solutions NW LLC PNW Holdings, LLC ES-3626 'I October 29, 2014 Page 9 i, The following parameters can be used for preliminary stormwater vauit design: • Allowable soil bearing capacity {dense native soil} 5,000 psf • Active earth pressure (unrestrained} 35 pcf ; • Active earth pressure (unrestrained, hydrostatic) 80 pcf • At-rest earth pressure (restrained) 55 pcf • At-rest earth pressure (restrained, hydrostatic) 100 pcf • Coefficient of friction 0.40 • Passive earth pressure 300 pcf • Seismic surcharge 6H* (active condition) 11 H* (at-rest condition) 'Vllhere H equals the retained height The vault walls should be backfilled with a 12-inch zone of free-draining material or a sheet drain that extends the full height of the wall backfill. The upper one foot of the wall backfill can consist of a less permeable soil, if desired. A perforated drain pipe should be placed alang the base of the wall and connected to an approved discharge location. If the elevation of the vault bottom is such that gravity flow to an flutlet is not possible from the base of the waN, the drain can be raised to allow drainage. The portion of the �ault below the drain pipe must be designed to inc{ude hydrostatic pressure. Design values accounting for hydrostatic pressure are included above. ESNW should observe grading operations for the vault and the subgrade conditions prior to concrete forming and pouring to confirm conditions are as anticipated, and to provide supplemental recommendations as necessary. Additionally, ESNW should be contacted to review final vault designs to confirm that appropriate geotechnical parameters have been incorporated. Infiltration Feasibilitv As a part of our scope of services, a determination of the feasibility for infiltration of stormwater runoff from downspouts and other impervious surfaces was required. , Due to the presence of very dense glacial till soil on the subject site, it is our opinion that in#iltration of stormwater on the subject site will be difficult to achieve. In addition, ESNW observed very dense glacial till soils extending to the maximum depth of exploration (eight feet below existing surface elevations). We recommend an altemative means of stormwater ', management be pursued in lieu of infiltration, due to the very dense quality of the soil present 'I across the entirety of the subject site. Earth Solutions NW,LLC PNW Holdings, LLC ES-3626 October 29, 2014 Page 10 Excavations and Siopes The Federai Occupation Safety and Health Administration (OSHA) and the Washington Industrial Safety and Health Act (WISHA) provide soil classification in terms of temporary slope inclinations. Based on the soil conditions encountered at the test pit iocations, the weathered native soils encountered in the upper approximately three to four feet of the test pit locations, and where groundwater seepage is not exposed, are classified as Type B by OSHA/WISHA. Temporary slopes over four feet in height in Type B soils must be sloped no steeper than 1 H:1 V (Horizontal:Vertical). Dense to very dense native soils encountered below about three to four feet where no groundwater seepage is exposed would be classified as Type A by OSHA/WISHA. Temporary slopes over four feet in height in Type A soils must be sloped no steeper than 0.75H:1V. The presence of perched groundwater may cause caving of the temparary slopes due to hydrostatic pressure. ESNW shoufd observe site excavations to confirm the soil type and allowable slope inclination. If the recommended temporary slope inclination cannat be achieved, temporary shoring may be necessary to support excavations. Permanent slopes should maintain a gradient of 2H:1V, or flatter, and should be planted with vegetation to enhance stability and to minimize erosion. A representative of ESNW should observe temporary and permanent slopes to confirm the slope inclinations, and to provide additional excavation and slope recommendations, as necessary. Utilitv Support and Trench Backfill ln our opinion, the soils anticipated to be exposed in utility excavations should be suitable for support of utilities. Organic or highly compressible soils encountered in the trench excavations should not be used for supporting utilities. The native soils are moisture sensitive and will therefore be difficult to use as structural trench backfill if the moisture content of the soil is high. Moisture conditioning of the soils will likely be necessary prior to use as structuraf backfill. Utifity trench backfill should be placed and compacted to the specifications of structural fill provided in this report, or to the applicable City of Renton specifications. Perched groundwater seepage should be anticipated within utility trench excavations. Pavement Sections I The performance of site pavements is largely related to the condition of the underiying subgrade. To provide adequate pavement performance, the subgrade should be in a firm and unyielding condition when subjected to proofrolling with a loaded dump truck. Structural fill in pavement areas should be compacted as recommended in the "Site Preparation and Earthwork" section of this report. It is possible that soft, wet, or otherwise unsuitable subgrade areas may still exist after base grading acfivities. Areas of unsuitable or yielding subgrade conditions will require remedial measures such as overexcavation, cement treatment, placement of a geotextile and thicker crushed rock or structuraf fill sections prior to pavement. For lightly foaded pavement areas subjected primarily to passenge� vehicles, the following preliminary pavement sections can be considered: Earth Solutions NW,LLC PNW Holdings, LLC ES-3626 October 29, 2014 Page 11 • Two inches of hot-mix asphalt (HMA) placed over four inches of crushed rock base (CRB), or; • Two inches of HMA placed over three inches of asphalt treated base (ATB). The HMA, ATB and CRB materials should conform to WSDOT specifications. All soil base material should be compacted to at least 95 percent of the maximum dry density. Final pavement design recommendations can be provided once final traffic loading has been determined. In our opinion, additional drainage measures should be considered for pavement subgrade areas. Such drainage measures could include the installation of drainlines along the sides of crowned roadways and along the centerline for roadways with inverted crowns. If areas of seepage are exposed in roadway excavations, drains should be installed in these areas to allow removal of the water. Specific recommendations and details for roadway drainage can be provided upon request. LIMITATIONS The recommendations and concfusions provided in this geotechnical engineering study are professional opinions consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions in this area. A warranty is not , expressed or implied. Variations in the soil and groundwater conditions observed at the test I locations may exist, and may not become evident until cvnstruction. 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Sr �__J� �_�.�II,_� ; > � J'r'+gs t�i!, '�"- �� t��l' j�'n�'r ��F +1'1� T v• � ''�m � :1. �_ J��'��'� z �f" � F� l� ,�!'`A 3! r�� ,1'�`� ; t� ,rt y �� F;� h�: � -..i - �:�r _ ��6�+�+� �: dtl� y4 �� f �-�''c # � �� '�Y tir t � �ISrnS��+�, .+: ?� fJ . i -r2 � fM" � � Ft ' �Tt"� AF� �r' PF1nF Y.w=. �� •ie� 1 �. !V' _�t"s'• : • � �� VE �Tt�'"'_ �1 a�rarru<<ti y�i�F&�.__.�Fc 5 x.� y `v �� .-, . yf�L`�. ��i}�.- �� i.�P�E _� ��.'_� A �cr{'�tS v�� V4�Y:= �"'� -��.y � T S��2-T11. ST 4.. i + ,� _ ?a�_ _ ;sT�'' ��-�sz :�a�e.��2n� �°- ._��1�4'�T� _�s�t�,�� __�_1.�:T :i - � -F� I ,� v ,., � E E e . P � NORTH ' ' - Reference: � ___•a ' King County, Washington - Map 626 ' By The Thomas Guide Vicinity Map ' Rand McNally Maertins Plat ' 32nd Edition Renton, Washington Drwn. GLS Date 10/28/2014 Proj. No. 3626 NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information Checked SHA Date Oct. 2014 Plate � i resulting from black&white reproductions of this plate. - - - --�-_ _.. .. N.E. 16TH STREET ' � ,- - - - - -- � _ _ _ � _ � __._ - --- � E v -�� ` � TF'3� i ; NORTH � � �I ' i � � � __ �. _ _ ___ �-- -- - - — —s ] � I i � I i � � � � y � � I P-1 ' .' � � � �- -- - - ° — -- - - -- - ^�� , � TP-2� i _ , , i ! ; ; i i ` ; , , � - � - ^- -- - - � - - -� 0 50 1 00 200 ,- - I TP-4 �� , � � Scale in Feet � � , 5 Scale 1" = 100' � �__ _ _ _� - - - - � i � _ _ .__�_ _ � __�� , ., � � I ` I � _ _ _ � _ _ __ _ � LEGEND � �' � f - - -� t: � —�—Approximate Location of f i � � TP-1 � ESNW Test Pit, Proj. No. � F � __ __ _ __ _ _ _ _ � ES-3626, Oct. 2014 I i � � �TP-5 � ,---- - - � —•— � � s Subject Site � - - - - -- - � � _ � � � � _ _ __ -__ – __ ____ _� �; Proposed Lot Number i .. � G t � ;g� ' Proposed Storm Drainage ! ' ' ' Area aL__ '—� I _ � j — — — — — — --- � _ � i � � I I � � ~ ` + � \ � 1 ' ' � — w — __ � I t i � „ = I `:- � � _ � � � � � �� NOTE:The graphics shown on this plate are not intended for design e �.• ' purposes or precise scale measurements,but only to illustrate the '�`=� � �I approximate test locations relative to the approximate locations of existing and I or proposed site features.The information illustrated Test Pit Location Plan is largely based on data provided by the client at the time of our Maertin Plat siudy.ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. Ref1tOI1, Wash ington NOTE:This plate may contain areas of color.ESNW cannot be p�n. GLS Date 10/28/2014 Proj. No. 3626 responsible for any subsequent misinterpretation of the information resulting from black&white reproductions of this plate. Checked SHA Date Oct. 2014 Plate 2 - — --- ------ I i 18" Min. o � p � � o 00 0 0� � � � � � o0 � ° �°� °o o� °, o��°� B o, o 0 0 0 0 `e o'o' ,o o� �o 0 , o ,',ao ' oa o00 60 '° ' � ' ' o O o o � o0 0000, o 0 a ,o ° 0000 , o o , o 0 0 0 0 0 0 �°c� �� o 0o a�o o �oo a o 00 � o� °o � o o�oo 0 00 � Structural 00 ` ` � �� ° �a� ° � Fill ,� a � ` S � o00000 00 0 0 0 0 o , o , o 0 000 ',00 0 0,0 0 0 0 , ,, o� oo'p ,, oa ` o ' ,o ' '° ' ' ' °g o ' � o � � � � � —� � �_ '` � ` ` � oao � °o oe 0000�o 0 0 � � � o 00 0 0 ., a , �'fti•ti f 1�•� �r . j f+ .fti• ��. � Perforated Drain Pipe NOTES: (Surround In Drain Rock) • Free Draining Backfill should consist of soil having less than 5 percent fines. Percent passing#4 should be 25 to 75 percent. � Sheet Drain may be feasible in lieu SCHEMATIC ONLY- NOT TO SCALE of Free Draining Backfill, per ESNW NOTA CONSTRUCTION DRAWING recommendations. • Drain Pipe should consist of perforated, rigid PVC Pipe surrounded with 1" Drain Rock. LEGEND: v ��Q � � 9 = I p 'op o Free Draining Structural Backfill � � _ � ' ,.�'. � - � �r�f�j�f� _ i .ti.ti.ti.ti - ':;:�ti�:�ti 1 inch Drain Rock RETAINING WALL DRAINAGE DETAIL r•r• Maertin Plat Renton, Washington Drwn. GLS Date 10/29/2014 Proj. No. 3626 Checked SHA Date Oct. 2014 Plate 3 --- ----- - _- — -- - ------ - Slo�► I � �: :'�8":EAlliri.:):;:::.. '��f~:•�r�1 •ti• .'f. .ti ;.' f:f. �r��. tir :,•�� 2" (Min.) PerForated Rigid Drain Pipe ' (Surround with 1" Rock) NOTES: • Do NOT tie roof downspouts to Footing Drain. SCHEMATIC ONLY- NOT TO SCALE • Surface Seal to consist of NOT A CONSTRUCTION DRAWING 12" of less permeable, suitable soil. Slope away from building. LEGEND: � Surface Seal; native soil or other low permeability material. � � tti?tit��'ti� � � �.�'_ I . :r::.::ti: 1' Drain Rock _ 'I i FOOTING DRAIN DETAIL ! Maertin Plat Renton, Washington Drwn. GLS Date 10/29/2014 Proj. No. 3626 Checked SHA Date Oct. 2014 Plate 4 I� - — - - - - -- -- - - Appendix A Subsurface Exploration ES-3626 The subsurface conditions at the site were explored by excavating a total of five test pits excavated with a track-hoe acrass accessible portions of the property. The subsurFace explorations were completed in October of 2014. The approximate test pit locations are illustrated on Plate 2 of this report. Logs of the test pits are provided in this Appendix. The test pits were excavated to a maximum depth of eight feet below existing grades. Earth Solutions MN,LLC "� Earth Solutions NWLLC ' SOlL CLASSIFICATION CHART MAJOR DtVISIONS SYMBOLS TYPICAL GRAPH LETTER DESCRiPTtONS . CLEAN '�� WELL-GRADED GRAVELS,GRAVEL- GRAVEL GRAVELS • ��' � Gw SAND MIX7URES,LITTLE OR NO AND �S.� FINES GRAVELLY ° SOILS oU" e� POORLY-GRADEOGRAVELS, (lffTl.E OR NO FINES} o ODo 0 GP GRAVEL-SAND MIXTURES,LITRE �O oQ OR NO FlNES COARSE " GRAINED GRAVELS WITN °� '° ° si�rY cRav�s,GRAVEI-SAND- SOILS MORETFiAN50% FINES � 0 GM SILTMIXTURES OF COARSE � �o FRACTION RETAINED ON NO. 4 SIEVE (APPRECIA@lE GC CLAYEYGRAVELS,GRAVEL-SAND- AMOUrIT OF FINES) CLAY MIXTURES MORE THAN 5G°h SAND CLEAN SANDS SVW SANDS,�LIATTLE OR NO F NE3�LLY OF MATERIAL IS AND LARGERTHAN SANDY POORLYI',RADEDSANpS, No.20o sle� SOILS SIZE (IITRE OR NO FINES) �'P GRAVELLY SANU,LITTLE OR NO FINES MORE T}iAN 50•/ SANDS WITH S.M SILTY SANOS,SANO-SILT OF COARSE FINES MIXTURES fRACTION - PASSING ON NO. 4 SfEVE (APPRECIABLE S`+ CLAYEY SANDS,SAND-CLAY AMOUNT OF FINES) MIXTURES INORGANIC SILTS AND VERY FINE ML SANDS.ROCK FLOUR,SILTY OR CLAYEY FINE SANOS OR CIAYEY SILTS WITH SLIGHT PLAST7CITY %' � � INCRGANIC CL4YS OF LOW TO FWE SILTS LIQUID U61iT / � MEDIUM PLASTICfiY,GRAVELLY AND LESS THAN SC� %j/�� C+L CtAYS,SANDY CLAYS,SILTY GRAINED CLAYS �� cwvs,LEAN CIAYS SOILS - - OL ORGANIC SILTS AND ORGANIC - - — SILIY CLAYS OF LOW PLASTICITY MORE TFU4N 50% INORGANIC SILTS,MICACEOUS OR OF AMTERIAL lS MH DIATOMACEOUS FINE SAND OR SMALLER T}iAN SIITY SOILS NO.200 SIEVE S�� SILTS LIQUID LIMIT INORGANIC CLAYS OF HIGH CLAYS GREATER THAN 50 CH PLASTICITY .��,��.�..::a :�...�_M OH ORGANIC CLAYS OF MEDIUM TO HiGH PLASTICITY,ORGANIC SILTS ..i....v �� "^" PEAT,HUIutUS,SWAMP SOILS WITH HIGHLY�RGANIC SOILS ; `` ` , PT HIGH ORGANIC CONTENTS DUAL SYMBOLS are used to indicate borde�line soil classifications. The discussion in the text of this report is necessary for a proper understanding of fhe nature of the material presented in the attached logs. Earth Solutions NW TEST PIT NUMBER TP-1 1805-136th Place N.E.,Suite 201 ' � Bellevue,Washington 98005 PAGE 1 OF 1 Telephone: 425-449-d704 Fax: 425�49-4711 CLIENT PNW Holdin�s,LLC PROJEC7 NAME Maertins Plat_ __ PROJECT NUMBER 3626 _ __f PROJECT LOCATION Renton Washington ___ __..___.....__ w__.._ __ ---- DATE STARTED 10l21/14 COMPLETED 10/21/14 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR Client Provided GROUfVD WATER LEVELS: EXCAVATION METHOD AT T1ME OF EXCAVATION — LOGGED BY SHA CHECKED BY KRC AT END OF EXCAVATION — NOTES Depth of Topsoil&Sod 6":field grass AFTER EXCAVATION — w �� U W S �r �g TESTS � �O MATERIAL DESCRIPTION o a� � Q Z C9 � 0 TPSL '�= =0.5 TOPSOIL --_ - -- - __ ---- — Brown silly SAND with gravel,medium dense,moist(Weathered Till) -becomes very dense and unweathered SM MC=4.90% Fines=25.60% 4 5 - - — — - - — -- -- ----- __ _ -- Test pit terminated at 4.5 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 4.5 feet. 0 � H � tA � F Z (� a' c� � J � � _ m J � W Z W � Earth Solutions NW TEST PIT NUMBER TP-2 1805-136th Place N.E.,Suite 201 � � Bellevue,Washington 98005 PAGE 1 OF 1 Teteph one: 425�49-4704 Fax: 425�49-4711 CLIENT PNW Holdings,LLC PROJECT NAME Maertins Plat PROJECT NUMBER 3626 PROJECT LOCATfON Renton_Washinqton DATE STARTED 10/21/14 COMPLETED 10l21I14 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR Client Provided GROUND WATER LEVELS: EXCAVATION ME7HOD AT TiME OF EXCAVATION --- LOGGED BY SHA CHECKED BY KRC AT END OF EXCAVATION — NOTES Depth of Topsoil&Sod 8":field qrass AFTER EXCAVATION -- w _ �W N U W� W°� TESTS � �p MATERIAL DESCRIPTION � �Z � ¢ � N 0 TPSL �-= ��p 5 TOPSOIL .� — -- _ � , Brown silty SAND with gravel,medium dense,moist(Fill) r SM 2.9 � -- Brown silty SAND with gravel,dense,moist(Unweathered Till) I r� -increased sand content SM MC=7.50% � 1_ao __..r — ____ --- _--_ _ -- --- -- Tes[pit terminated at 8.0 feet below existing grade.No groundwater encountered during exca�ation. Bottom of test pit at 8.0 feet. v � r ❑ � � z � 'a � N � J � ~ _ m J � W Z W � Earth Solutions NW TEST PIT NUMBER TP-3 1805-136th Place N.E.,Suite 201 PAGE 1 OF 1 ' ' Bellevue,Washington 98005 Telephone� 425-449-4704 Fax: 425�49-4711 CLIENT PNW Holdings,LLC PROJECT NAME Maertins Plat PROJECT NUMBER 3626 PROJECT LOCATION Renton Washington DATE STARTED 10/21l14 COMPLETED 10/21/14 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR Client Provided GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION -- LOGGED BY SHA CHECKED BY KRC AT END OF EXCAVATION -- NOTES Depth of Topsoil8 Sod 6":field grass AFTER EXCAVATION — w _ �� ai U x W� �� TESTS � �O MATERIAL DESCRIPTION o a� aZ = � 0 � PSL ='-' ' 0.5 TOPSOIL � - ---. __ - -----_ _ __._ — Brown silty SAND with gravel,medium dense,moist(Weathered Till) MC=16.40% Fines=26.40% SM -becomes very dense and unweathered 5 MC=10.10% 6.0 - --- -- -- __.—___ _----...-- —_.._ Test pit tertninated at 6.0 feet below existing grade.No groundwater encountered during excavaGon. Bottom of test pd at 6.0 feet. � � r � � � � a' � r� J � a F- S m � w Z w � Earth Solutions NW TEST PIT NUMBER TP-4 1805-136th Place N.E.,Suite 201 � ' Bellevue,Washington 98005 PAGE 1 OF 1 Te I e p h o n e: 425�49�704 Fax: 425-449-4711 CLIENT PNW Holdings.LlC PROJECT NAME Maertins Plat PROJECT NUMBER 3626 PROJECT LOCATION Renton,Washinqton DATE STARTED 10/21/14 COMPLETED 10/21/14 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR Client Provided GROUND WATER LEVELS: EXCAVATI�N METHOD AT TIME OF EXCAVATION — LOGGED BY SHA CHECKED BY KRC AT END OF EXCAVATION — NOTES Depth of Topsoil 8 Sod 3":field qrass AFTER EXCAVATION — w �w �? _ W� W 00 TESTS � �O MATERIAL DESCRIPTEON � Qz � C7 � 0 Tpg�,`= •'0 5 TOPSOtL - -_....---- --------- --_....—._ Brown silty SAND with gravel,medium dense,moist(Weathered Till) -becomes very dense and unweathered SM MC=3.30% 5 5.5 _ _ �Test pit terminated at 5.5 feet below existing grade.No groundwater encountered during excavation. Bottom of test pit at 5.5 feet. � � r- � ai � � � a' tl � J � � _ � J � W 2 w � Earth Solutions NW TEST PIT NUMBER TP-5 1805-136th Place N.E.,Suite 201 ' ' Bellevue,Washington 98005 PAGE 1 OF 1 Te I e p h o n e: 425-44 9-4704 Fax: 425-449-4711 CLIENT PNW Holdings.LLC PROJECT NAME Maertins Plat PROJECT NUMBER 3626 PROJECT LOCATION Renton,Washinqton DATE STARTED 10/21l14 COMPLETED 10l21/14 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR Client Provided GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION — LOGGED BY SHA CHECKED BY KRC AT END OF EXCAVATION --- NOTES Depth of Topsoil&Sod 8":field qrass AFTER EXCAVATION — _ w _ �w � U W� a j TESTS � �O AhATERIAL DESCRIPTfON � Q Z � (� � 0 PSL '` ``9 5 TOPSOIL _ Brown silty SAND with gravel,dense,moist(Weathered Till) -becomes very dense and�nweathered 5M � MC=4.10% 6.0 Test pit terminated at 6.0 feet below existing grade.No groundwater encountered during excavation. Bottom of test pit at 6.0 feet. a I � F � (� � z C� a' � n m J � a � x m J � IlA Z W � Appendix B Grain Size Distribution ES-3626 Earth Solutions NW, LLC ,, , Earth Solutions NW GRAIN SIZE DISTRIBUTION - , ;.,., 1805-136th Place N.E.,Suite 201 �� , Bellevue,WA 98005 Telephone: 425-284-3300 CUENT PNW Holdinas;LLC PROJECT NAME Maertins Plat PROJECT NUMBER ES-362$ PROJECT LQCATIOM Renton U.S.SIEVE OPENING iN INCHES � U.S.SIEVE NUMBERS I HYDROMETER 6 4 3 2 1 3I4 1/23/S 3 4 6 810 ��.16 20 30 40 50 60 100'140200 100 95 - - - — --._ _ 90 - -- 85 - __ -- -- 80 - - 75-___ _ _ 70- -. ._...- - � 65 - - _ � 60 - - � � 55 - - m � W 50 - - - z LL F- 45 z w � 40 --- w a 35 - -- — - — 30 - — 25 - - - 20 - -- - -- - 15 - -- -— 10 - ._ _ - - - - 5 - - 0 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS --- --- - COBBLES — GRAVEL SAND ___,_ SILT OR CLAY coarse fine coarse medium fine Specimen Identification Classification LL PL PI Cc Cu � o TP-1 4.Oft. Gray Silty SAND with Gravel,SM = __ - ---__ __s --- � � TP-3 2.Oft. Brown Silty SAND with Gravel,SM � -_ � ___-- 5 tA - - � � . __-.____._._ - _. n Specimen Identification D100 D60 D30 D10 %Grave! %Sand %Silt %Clay � � _ — __.. - - - _.___ ____ ? o TP-1 4.Oft. 37.5 0.684 0.099 23.5 50.9 25.6 (V _ . _ __ - --- - - _ � � TP-3 2.Oft. 37.5 1.024 0.095 27.9 45.7 26.4 W - N- ____- .____� h Z � ...._'__- _. ._._._..__- � � � Report Distribution ES-3626 EMAIL ONLY PNW Holdings, LLC 9675 - 36th Street, Suite 105 Mercer Island, Washington 98040 I Attention: Mr. Justin Lagers Earth Solutions NW,LlC SECTION VII OTHER PERMITS, VARIANCES AND ADJUSTMENTS 1. Structural vault permit. 2. Construction Stormwater General Permit —WSDOE 3. Wall Structural Building Permit. '2015 D. R. STRONG Consulting Engineers Inc. Maertins Ranch Page 42 Technical Information Report City of Renton � � I 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 including trees to be saved. 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 ingresslegress. 5. Sediment Retention — Surface water collected from disturbed areas of the Site shall be routed through a Baker Tank prior to release from the Site. The Baker Tank will be utilized 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. Surface water controls shall be installed concurrently with andlor immediately following rough grading. 7. Dewatering Control —Will be provided as needed per approved plan by COR. 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 — The permanent stormwater detention vault will be constructed and runoff collected in the Baker Tank will be discharged to the permanent detention vault outfall system. ', 2015 D R. STRONG Consul:ing Erg�meers Inc fJlae��t��ns Ranch Paae 43 T�r_h��r�l Irfo-r-�a�i�r Revort C t�.� o`P.e�it�� SWPPS PLAN DESIGN (PART B) '', Construction activities that could contribute pollutants to surface and storm water I', include the following, with applicable BMP's listed for each item: 1. Storage and use of chemicals: Utilize source control, and soil erosion and ' sedimentation control practices, such as using only recommended amounts of chemical materials applied in the proper manner; neutralizing concrete wash ' water, and disposing of excess concrete material only in areas prepared for concrete placement, or return to batch plant; disposing of wash-up waters from water-based paints in sanitary sewer; disposing of wastes from oil-based paints, solvents, thinners, and mineral spirits only through a licensed waste management firm, or treatment, storage, and disposal (TSD) facility. 2. Material delivery and storage: Locate temporary storage areas away from vehicular traffic, near the construction entrance, and away from storm drains. Material Safety Data Sheets (MSDS) should be supplied for all materials stored, and chemicals kept in their original labeled containers. Maintenance, fueling, and repair of heavy equipment and vehicles shall be conducted using spill prevention and control measures. Contaminated surfaces shall be cleaned immediately following any spill incident. Provide cover, containment, and protection from vandalism for all chemicals, liquid products, petroleum products, and other potentially hazardous materials. 3. Building demolition: Protect stormwater drainage system from sediment-laden runoff and loose particles. To the extent possible, use dikes, berms, or other methods to protect overland discharge paths from runoff. Street gutter, sidewalks, driveways, and other paved surfaces in the immediate area of demolition must be swept daily to collect and properly dispose of loose debris and garbage. Spray the minimum amount of water to help control windblown fine particles such as concrete, dust, and paint chips. Avoid excessive spraying so that runoff from the Site does not occur, yet dust control is achieved. Oils must never be used for dust control. 4. Sawcutting: Slurry and cuttings shall be vacuumed during the activity to prevent migration offsite and must not remain on permanent concrete or asphalt paving overnight. Collected slurry and cuttings shall be disposed of in a manner that does not violate ground water or surFace water quality standards. 5. Spill Containment Kit: Keep material storage areas clean, organized and equipped with an ample supply of appropriate spill clean-up material (spill kit). The spill kit should include, at a minimum: • 1-Water Resistant Nylon Bag • 3-Oil Absorbent Socks 3"x 4' • 2-Oil Absorbent Socks 3"x 10' • 12-Oil Absorbent Pads 17"x19" �, • 1-Pair Splash Resistant Goggles '� • 3-Pair Nitrile Gloves • 10-Disposable Bags with Ties 02015 D. R.STRONG Consulting Engineers Inc. Maertins Ranch Page 44 Technical Information Report City of Renton I • Instructions The complete CSWPPP is included in Appendix D of this report. '' ��2p15 D. R STRONG Consulting Engineers Inc. Maertins Ranch Page 45 Technical Information Report City of Renton SECTION IX BOND QUANTITIES, FACILITY SUIVIMARIES, AND DECLARATION OF COVENANT 1. Bond Quantity Worksheet— attached in Appendix B 2. The Stormwater Facility Summary Sheet is included in this section 3. Declaration of Covenant— attached in Appendix E �2015 D. R. STRONG Consulting Engineers Inc. Maertins Ranch Page 46 Technical Information Report City of Renton STORMWATER FACILITY SUMMARY SHEET Development Maertins Ranch Date March 18, 2015 Location 1508 Ilwaco Avenue NE, Renton, Washinqton ENGINEER DEVELOPER Name Maher A. Joudi, P.E. Name Firm D. R. STRONG Consulting Firm Albacore — ACH, LLC En ineers, Inc. Address 620 7 Avenue Address 9675 SE 36 Street, #105 Kirkland, WA 98033 Mercer Island, WA 98040 Phone (425) 827-3063 Phone (206) 588-1147 Developed Site: 4.079 acres Number of lots 13 Number of detention facilities on Site: Number of infiltration facilities on Site: 1 vaults vaults 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 East Renton Plateau Ma 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 detention/WQ vault sand filter vault (basic or large?) combined detention/wetpond 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?) �2015 D. R. STRONG Consulting Engineers Inc Maertins Ranch Page 47 Technical Information Report City of Renton catch basin inserts: Manufacturer � pre-settling structure: Manufacturer I DESIGN INFORMATION INDIVIDUAL BASIN �'� Water Qualit design flow I Water Qualit treated volume Drainage basin(s) Onsite area (includes fronta e) 4.079 Offsite area T pe of Stora e Facilit Vault Live Stora e Volume (re uired) 50,288 Predev Runoff Rate 2- ear 0.150 10- ear 0.260 100- ear 0.378 Developed Runoff Rate 2- ear 0.072 (rdout) 10- ear 0.220 100- ear 1.450 T pe of Restrictor Frop-Tee Size of orifice/restriction No. 1 1.10 No. 2 1.20 No. 3 1.00 I <2015 D R. STRONG Consulting Engineers Inc Maertins Ranch Pa e 48 II 9 Technical Information Report City of Renton SECTION X OPERATIONS AND MAINTENANCE MANUAL See Appendix C for excerpts from the 2009 King County Surface Water Design Manual with regard to Operations and Maintenance. 2015 D. R STRONG Co��su'�tin� Enp�r�cer In� P,1aart�ns Ranch Pa�e 49 Technic�l Ir`orma~�on Repo�t Ci�y of Renton - I APPENDICES APPENDIX "A" LEGAL DESCRIPTION PARCEL A: THE NORTH 677.44 FEET OF THE WEST 1/2 OF THE WEST 1/2 OF THE SOUTHEAST 1/4 OF THE SOUTHEAST 1/4 OF SECTION 3, TOWNSHIP 23 NORTH RANGE 5 EAST., W.M., IN KING COUNTY, WASHINGTON; EXCEPT THE WEST 130 FEET OF PORTION LYING SOUTH OF A LINE 339.5 FEET SOUTH OF THE NORTH LINE; EXCEPT THAT PORTION OF SAID NORTH 677.44 FEET LYING SOUTH OF THE FOLLOWING DESCRIBED LINE: BEGINNING AT THE INTERSECTION OF THE SOUTH LINE OF THE NORTH 677.44 FEET WITH THE EAST LINE OF THE WEST 1/2 OF THE WEST 1/2 OF THE SOUTHEAST 1/4 OF THE SOUTHEAST 1/4 OF SAID SECTION 3; THENCE NORTH 87 DEGREES, 49 MINUTES AND 08 SECONDS WEST ALONG SAID SOUTH LINE A DISTANCE OF 89.01 FEET TO THE BEGINNING OF SAID LINE; THENCE NORTH 67 DEGREES, 07 MINUTES, 57 SECONDS WEST A DISTANCE OF 119.88 FEET TO INTERSECTION OF THE EAST LINE OF THE WEST 130 FEET OF THE SOUTHEAST 1/4 OF THE SOUTHEAST 1/4 OF SAID SECTION 3, SAID INTERSECTION BEING TERMINUS OF LINE; EXCEPT PORTION, IF ANY, CONVEYED TO JAMES L. DIXON, ET UX, BY DEEDS RECORDED UNDER RECORDERS NOS. 6468344 AND 7207120398. PARCEL B: A NON-EXCLUSIVE EASEMENT FOR INGRESS AND EGRESS AS CREATED BY INSTRUMENT RECORDED AS RECORDING NUMBER 7609140487. TAX PARCEL NUMBER: 032305902101 APPENDIX "B" BOND QUANTITY WORKSHEET � �2015 D. R STRONG Consulting Engineers Inc Maertins Ranch Page 51 Technical Information Report City of Renton Site Improvement Bona Quantity Worksheet Webdate: >_/2008 � King County Department of Development & Environmental Services 900 Oakesdale Avenue Southwest Renton, Washington 98057-5212 For alternate formats, call 206-296-6600. 206-296-6600 TTY 206-296-7217 Project Name: Maertins Ranch �ate: 21-May-15 �ocat�on: Renton, Washington Project No.: 14103 Activity No.: Note: All prices include labor, equipment, materials, overhead and Clearing greater than or equal to 5,000 board feet of timber? profit. Prices are from RS Means data adjusted for the Seattle area or from local sources if not included in the RS Means database. yes X no If yes, Forest Practice Permit Number: (RCW 76.09) Page 1 of 9 I� Unit prices updated: 02/12/02 Version: 11/26/2008 Bond Quantity Worksheet14103.x1sx Report Date: 7/6/2015 Site Improvement Bona Quantity Worksheet Webdate: �/2008 Unit #of Reference# Price Unit Quantity Applications Cost EROSION/SEDIMENT CONTROL Number Backfill & compaction-embankment ESC-1 $ 5.62 CY Check dams, 4"minus rock ESC-2 SWDM 5.4.6.3 $ 67.51 Each 11 1 743 Crushed surfacin 1 1/4" minus ESC-3 WSDOT 9-03.9 3 $ 85.45 CY Ditchin ESC-4 $ 8.08 CY 315 1 2545 Excavation-bulk ESC-5 $ 1.50 CY 1 Fence, silt ESC-6 SWDM 5.4.3.1 $ 1.38 LF 1251 1 1726 Fence, Tem ora NGPE) ESC-7 $ 1.38 LF Hydroseedin ESC-8 SWDM 5.4.2.4 $ 0.59 SY 19742 1 11648 Jute Mesh ESC-9 SWDM 5.4.2.2 $ 1.45 SY Mulch, b hand,straw, 3"deep ESC-10 SWDM 5.4.2.1 $ 2.01 SY Mulch, b machine, straw, 2"deep ESC-11 SWDM 5.4.2.1 $ 0.53 SY 19742 1 10463 Pipin ,temporary, CPP, 6" ESC-12 $ 10.70 LF Piping,temporary, CPP, 8" ESC-13 $ 16.10 LF Piping,tempora , CPP, 12" ESC-14 $ 20.70 LF 195 1 4037 Plastic covering,6mm thick, sandba ed ESC-15 SWDM 5.4.2.3 $ 2.30 SY 820 1 1886 Rip Rap, machine placed; slopes ESC-16 WSDOT 9-13.1(2) $ 39.08 CY 1 Rock Construction Entrance, 50'x15'x1' ESC-17 SWDM 5.4.4.1 $ 1,464.34 Each Rock Construction Entrance, 100'x15'x1' ESC-18 SWDM 5.4.4.1 $ 2,928.68 Each 1 1 2929 Sediment pond riser assembly ESC-19 SWDM 5.4.5.2 $ 1,949.38 Each Sediment trap, 5' hi h berm ESC-20 SWDM 5.4.5.1 $ 17.91 LF Sed.trap,5'high, riprapped spillway berm section ESC-21 SWDM 5.4.5.1 $ 68.54 LF Seeding, by hand ESC-22 SWDM 5.4.2.4 $ 0.51 SY Soddin , 1"deep, level ground ESC-23 SWDM 5.4.2.5 $ 6.03 SY Sodding, 1"deep, sloped round ESC-24 SWDM 5.42.5 $ 7.45 SY TESC Supervisor ESC-25 $ 74.75 HR 24 1 1794 Water truck, dust control ESC-26 SWDM 5.4.7 $ 97.75 HR 16 1 1564 WRITE-IN-ITEMS **** (see paqe 9) Inlet Protection Grate $ 25.00 Each 21 1 525 3-10k Gallon Baker Tank Sump Pump ESC SUBTOTAL: $ 39,859.41 30%CONTINGENCY&MOBILIZATION: $ 11,957.82 ESC TOTAL: $ 51,817.23 COLUMN: A Page 2 of 9 Unit prices updated: 02/12/02 Version: 11/26/2008 Bond Quantity Worksheet14103.x1sx Report Date: 7/6/2015 Web dat .""�2/2008 I Site Improvement Bc Quantity Worksheet , Existing Future Public Private Quantity Completed Right-of-Way Right of Way improvements (Bond Reduction)' &Draina e Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Com lete Cost GENERALITEMS No. Backfill&Compaclion-embankment GI-1 $ 5.62 CY Backfill&Compaction-trench GI-2 $ 8.53 CY 802 6,841.06 358 3,053.74 137 1,168.61 Clear/Remove Brush,b hand GI-3 $ 0.36 SY Clearin /Grubbin ITree Removal GI-4 $ 8,876.16 Acre 0.27 2,396.56 0.87 7,722.26 2.9 25,740.86 Excavation-bulk GI-5 $ 1.50 CY 34 51.00 3190 4,785.00 5595 8,392.50 Excavation-Trench GI-6 $ 4.06 CY 940 3,816.40 395 1,603.70 145 588.70 Fencin ,cedar,6'hi h GI-7 $ 18.55 LF Fencin ,chain link,vin I coated, 6'hi h GI-8 $ 13.44 LF 513 6,894.72 Fencing,chain link, ate,vin I coated, 2 GI-9 $ 1,271.81 Each Fencin ,split rail,3'hi h GI-10 $ 12.12 LF Fill 8 compact-common barrow GI-11 $ 22.57 CY 290 6,545.30 Fill&compact- ravel base GI-12 $ 25.48 CY Fiil&com act-screened topsoil GI-13 $ 37.85 CY Gabion, 12"deep,stone filled mesh GI-14 $ 54.31 SY Gabion, 18"dee ,stone filled mesh GI-15 $ 74.85 SY Gabion,36"deep,stone filled mesh GI-16 $ 132.48 SY Gradin ,fine,b hand GI-17 $ 2.02 SY Gradin ,fine,with rader GI-18 $ 0.95 SY Monuments,3'lon GI-19 $ 135.13 Each 3 405.39 Sensitive Areas Si n GI-20 $ 2.88 Each Soddin , 1"dee ,slo ed round GI-21 $ 7.46 SY Surve in ,line& rade GI-22 $ 788.26 Da 1 788.26 2 1,576.52 3 2,364.78 Surve in ,lot location/lines GI-23 $ 1,556.64 Acre 4.079 6,349.53 Traffic control crew 2 fla ers GI-24 $ 85.18 HR 24 2,044.32 Trail,4"chipped wood GI-25 $ 7.59 SY Trail,4"crushed cinder GI-26 $ 8.33 SY Trail,4"top course GI-27 $ 8.19 SY Wall,retainin ,concrete GI-28 $ 44.16 SF Wall,rockery GI-29 $ 9.49 SF 280 2,657.20 Page 3 of 9 SUBTOTAL 15,937.60 26,041.33 53,807.49 Unit prices updated: 02/12/02 "KCC 27A authorizes only one bond reduction. VerSiOn: 11/26/08 Bond Quantity Worksheet14103.x1sx Report Date: 7/6/2015 � Site Improvement Bc Quantity Worksheet Webdat- '^'�2,2008 Existing Future Public Private Bond Reduction* Right-of-way Right of Way Improvements &Draina e Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost ROADIMPROVEMENT No. AC Grinding,4'wide rnachine< 1000sy RI-1 $ 28.00 SY 184 5.152.00 AC Grindin ,4'wide machine 1000-200 RI-2 $ 15.00 SY AC Grindin ,4'wide machine>2000s RI-3 $ 7.00 SY AC Removal/Disposal/Repair RI-4 $ 67.50 SY 100 6,750.00 Barricade,t pe I RI-5 $ 30.03 LF Barricade,t e III Permanent) RI-6 $ 45.05 LF 26 1,171.30 Curb&Gutter,rolled RI-7 $ 17.00 LF Curb&Gutter,vertical RI-8 $ 12.50 LF 140 1,750.00 1600 20,000.00 Curb and Gutter,demolition and disposa RI-9 $ 18.00 LF 140 2,520.00 Curb,extruded asphalt RI-10 $ 5.50 LF Curb,extruded concrete RI-11 $ 7.00 LF Sawcut,asphalt,3"depth RI-12 $ 1.85 LF 167 308.95 366 677.10 Sawcut,concrete,per 1"de th RI-13 $ 1.69 LF 12 20.28 Sealant,as halt RI-14 $ 1.25 LF 167 208.75 366 457.50 Shoulder,AC, (see AC road unit price) RI-15 $ - SY Shoulder, ravel,4"thick RI-16 $ 15.00 SY Sidewalk,4"thick RI-17 $ 35.00 SY 80 2,800.00 910 31,850.00 Sidewalk,4"thick,demolition and dispos RI-18 $ 29.50 SY 80 2,360.00 �I Sidewalk,5"thick RI-19 $ 38.50 SY I Sidewalk,5"thick,demolition and dispos RI-20 $ 37.50 SY Si n,handicap RI-21 $ 85.28 Each Stripin ,per stall RI-22 $ 5.82 Each Stripin ,thermoplastic, for crosswalk) RI-23 $ 2.38 SF 33 78.54 ' Striping,4"reflectorized line RI-24 $ 0.25 LF 200 50.00 Page 4 of 9 SUBTOTAL 21,869.98 54,284.44 I� Unit prices updated: 02/12/02 'KCC 27A authorizes only one bond reduction. Version: 11/26/08 Bond Quantity Worksheet14103.x1sx Report Date: 7/6/2015 - Webdat� '^'�2I2008 I Site Improvement Bc Quantity Worksheet Existing Future Public Private Bond Reduction" Right-of-way Right of Way Improvements &Drainage Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost ROAD SURFACING (4"Rock=2.5 base 8�1.5"top course) For'93 KCRS(6.5"Rock=5"base&1.5"top course) For KCRS'93, (additional 2.5"base)add RS-1 � 3.60 SY AC Overla , 1.5"AC RS-2 $ 11.25 SY AC Overla ,2"AC RS-3 $ 15.00 SY 184 2,760.00 AC Road,2",4"rock,First 2500 SY RS-4 $ 21.00 SY AC Road,2",4"rock,Q .over 2500SY RS-5 $ 19.00 SY AC Road,3",4"rock,First 2500 SY RS-6 $ 23.30 SY 2390 55,687.00 AC Road,3",4"rock,Qt .over 2500 SY RS-7 $ 21.00 SY AC Road,5", First 2500 SY RS-8 $ 27.60 SY AC Road,5",Qt .Over 2500 SY RS-9 $ 25.00 SY AC Road,6",First 2500 SY RS-1 $ 33.10 SY AC Road,6",Qt .Over 2500 SY RS-11 $ 30.00 SY As halt Treated Base,4"thick RS-1 $ 20.00 SY 2390 47,800.00 Gravel Road,4"rock,First 2500 SY RS-1 $ 15.00 SY Gravel Road,4"rock,Q .over 2500 SY RS-1 $ 8.50 SY PCC Road,5",no base,over 2500 SY RS-1 $ 27.00 SY PCC Road, 6",no base,over 2500 SY RS-1 $ 25.50 SY Thickened Edge RS-1 $ 8.60 LF Page 5 of 9 SUBTOTAL 2,760.00 103,487.00 Unit prices updated: 02/12/02 `KCC 27A authorizes only one bond reduction. Version: 11/26/08 Bond Quantity Worksheet14103.x1sx Report Date: 7/6/2015 Site Improvement Bc Quantity Worksheet Webdat- "�-�2,�008 Existing Future Public Private Bond Reduction* Right-of-way Right of Way Improvements &Draina e Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost DRAINAGE (CPP=Corfugated PlastiC Pipe, N12 or Equivalent) For Culvert prices, Avera e of 4'cover was assumed.Assume perforated PVC is same price as solid pipe. Access Road, R/D D-1 $ 21.00 SY 33 693.00 Bollards-fixed D-2 $ 240.74 Each Bollards-removable D-3 $ 452.34 Each '(CBs include frame and lid) CB T pe I D-4 $ 1,257.64 Each 9 11,318.76 3 3,772.92 CB T pe IL D-5 $ 1,433.59 Each 3 4,300.77 CB T pe II,48"diameter D-6 $ 2,033.57 Each 3 6,100.71 1 2,033.57 for additional depth over 4' D-7 $ 436.52 FT 19 8,293.88 7 3,055.64 CB T pe II,54"diameter D-8 $ 2,192.54 Each for additional depth over 4' D-9 $ 486.53 FT CB T e II,60"diameter D-10 $ 2,351.52 Each for additional depth over 4' D-11 $ 536.54 FT CB T pe II,72"diameter D-12 $ 3,212.64 Each for additional depth over 4' D-13 $ 692.21 FT Throu h-curb Inlet Framework Add) D-14 $ 366.09 Each 4 1,464.36 Cleanout,PVC,4" D-15 $ 130.55 Each Cleanout,PVC,6" D-16 $ 174.90 Each 10 1,749.00 Cleanout,PVC,8" D-17 $ 224.19 Each Culvert, PVC,4" D-18 $ 8.64 LF Culvert,PVC,6" D-19 $ 12.60 LF 927 11,680.20 Culvert,PVC, 8" D-20 $ 13.33 LF Culvert,PVC, 12" D-21 $ 21.77 LF Culvert,CMP,8" D-22 $ 17.25 LF Culvert,CMP, 12" D-23 $ 26.45 LF Culvert,CMP, 15" D-24 $ 32.73 LF Culvert,CMP, 18" D-25 $ 37.74 LF Culvert,CMP,24" D-26 $ 53.33 LF Culvert,CMP,30" D-27 $ 71.45 LF Culvert,CMP,36" D-28 $ 112.11 LF I Culvert,CMP,48" D-29 $ 140.83 LF I Culvert,CMP,60" D-30 $ 235.45 LF I� Culvert,CMP,72" D-31 $ 302.58 LF Page 6 of 9 SUBTOTAL 14,394.59 22,866.10 17,202.12 Unit prices updated: 02/12/02 'KCC 27A authorizes only one bond reduction. VBrSiOn: 11/26/08 Bond Quantity Worksheet14103.x1sx Report Date: 7/6/2015 Site Improvement Bc Quantity Worksheet Webda� �-��z,zooe Existing Future Public Private Bond Reduction* Right-of-way Right of Way Improvements DRAINAGE CONTINUED &Drainage Facilities Quant. No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Com lete Cost Culvert,Concrete,8" D-32 � 21.02 LF Culvert,Concrete,12" D-33 $ 30.05 LF Culvert,Concrete,15" D-34 $ 37.34 LF Culvert,Concrete,18" D-35 $ 44.51 LF Culvert,Concrete,24" D-36 $ 61.07 LF Culvert,Concrete,30" D-37 $ 104.18 LF Culvert,Concrete,36" D-38 $ 137.63 LF Culvert,Concrete,42" D-39 $ 158.42 LF Culvert,Concrete,48" D-40 $ 175.94 LF Cuivert,CPP,6" D-41 $ 10.70 LF Culvert,CPP,8" D-42 $ 16.10 LF Culvert,CPP, 12" D-43 $ 20.70 LF 165 3415.5 650 13455 Culvert,CPP, 15" D-44 $ 23.00 LF Culvert,CPP, 18" D-45 $ 27.60 LF 129 3560.4 Culvert,CPP,24" D-46 $ 36.80 LF Culvert,CPP,30" D-47 $ 48.30 LF Culvert,CPP,36" D-48 $ 55.20 LF Ditchin D-49 $ 8.08 CY Flow Dispersal Trench (1,436 base+ D-50 $ 25.99 LF French Drain 3'de th) D-51 $ 22.60 LF Geotextile,laid in trench, ol ro lene D-52 $ 2.40 SY Infiltration ond testin D-53 $ 74.75 HR Mid-tank Access Riser,48"dia, 6'deep D-54 $ 1,605.40 Each Pond Overtlow Spillwa D-55 $ 14.01 SY Restrictor/Oil Se arator, 12" D-56 $ 1,045.19 Each Restrictor/Oil Separator, 15" D-57 $ 1,095.56 Each Restrictor/Oil Separator, 18" D-58 $ 1,146.16 Each 1 1146.16 Riprap,placed D-59 $ 39.08 CY Tank End Reducer(36"diameter) D-60 $ 1,000.50 Each Trash Rack, 12" D-61 $ 211.97 Each Trash Rack, 15" D-62 $ 237.27 Each Trash Rack, 18" D-63 $ 268.89 Each Trash Rack,21" D-64 $ 306.84 Each Page 7 of 9 SUBTOTAL 3415.5 18161.56 Unit prices updated: 02/12/02 'KCC 27A authorizes only one bond reduction. VersiOn: 11/26/08 Bond Quantity Worksheet14103.x1sx Report Date: 7/6/2015 Site Improvement Bc Quantity Worksheet Webda' '-'�2/2008 Existing Future Public Private Bond Reduction* Right-of-way Right of Way Improvements &Drainage Facilities Quant. Unit Price Unit Quant. Price Quant. Cost Quant. Cost Complete Cost PARKING LOT SURFACING No. 2"AC,2"to course rock&4"borrow PL-1 $ 21.00 SY 2"AC, 1.5" to course&2.5"base cour PL-2 $ 28.00 SY 4"select borrow PL-3 $ 4.55 SY 1.5"top course rock&2.5"base course PL-4 $ 11.41 SY UTILITY POLES 8'STREET LIGHTING Utili ole relocatibn cosfs must be accom anied b Franchise Utili 's Cost Statement Utilit Pole(s)Relocation UP-1 $ 10,000.00 Street Li ht Poles w/Luminaires UP-2 $ 4,000.00 15 60,000.00 WRITE-IN-ITEMS (Such as detention/water qualit vaults. No. Yard Drains WI-1 $ 450.00 Each 3 1,350.00 StormFilter,72"dia.Manhole WI-2 $ 21,300.00 1 21,300.00 Detention Vault WI-3 $ 265,000.00 1 265,000.00 WI-4 WI-5 WI-6 WI-7 WI-8 WI-9 wi-�o SU BTOTAL 346,300.00 1,350.00 I SUBTOTAL(SUM ALL PAGES): 58,377.67 571,140.43 72,359.61 , 30%CONTINGENCY 8�MOBILIZATION: 17,513.30 171,342.13 21,707.88 I'i GRANDTOTAL: 75,890.98 742,482.56 94,067.49 �I COLUMN: B C D E �, Page 8 of 9 Unit prices updated: 02/12/02 'KCC 27A authorizes only one bond reduction. Version: 11/26/08 Bond Quantity Worksheet14103.x1sx Report DBte: 7/6/2015 Site Improvement Bond Quantity Worksheet Webdate _ _2/2008 Original bond computations prepared by: Name: Maher A. Joudi, P.E. oate: 21-May-15 PE Registration Number: 45232 Tel.#: (425) 827-3063 Firm Name: DR STRONG Consulting Engineers, Inc. Aadress: 620 7th Avenue, Kirkland, WA 98033 Project No: 14103 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) $ 51,817.2 TEMPORARY OCCUPANCY*"" Existing Right-of-Way Improvements (B) $ 75,891.0 Future Public Right of Way&Drainage Facilities (C) $ 742,482.6 Private Improvements (D) $ 94,067.5 Calculated Quantity Completed (E) $ - Total Right-of Way and/or Site Restoration Bond"/"" (A+g) $ 127,708.2 (First$7,500 of bond*shall be cash.) Performance Bond`Amount (A+B+C+D) = TOTAL (T) $ 964,258.3 T x 0.30 $ 289,277.5 OR inimum on amount is 00. Reduced Performance Bond*Total "` (T-E) $ 964,258.3 Use larger o Tx30 0 or - (B+C)X Maintenance/Defect Bond'Total 0.25= $ 204,593.4 NAME OF PERSON PREPARING BOND'REDUCTION: Date: *NOTE: The word"bond"as used in this document means a financial guarantee acceptable to King County. **NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required. The restoration requirement shall include the total cost for all TESC as a minimum, not a maximum. In addition,corrective work,both on-and off-site needs to be included. Quantities shall reflect worse case scenarios not just minimum requirements. For example, if a salmonid stream may be damaged,some estimated costs for restoration needs to be reflected in this amount. The 30%contingency and mobilization costs are computed in this quantity. ***NOTE: Per KCC 27A,total bond amounts remaining after reduction shall not be less than 30%of the original amount(T)or as revised by major design changes. REQUIRED BOND'AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DDES Page 9 of 9 Unit prices updated: 02/12/02 Check out the DDES Web site at www.kinpcounty.qov/permits Version: 11/26/08 Bond Quantity Worksheet14103.x1sx Report Date: 7/6/2015 � APPENDIX "C" OPERATIONS AND MAINTENANCE MANUAL ,2015 D. R. STRONG Consulting Engineers Inc Maertins Ranch Page 52 Technical Information Report City of Renton APPI=.NDII A ��t��NTEI�Ai�Cli KI:QL;IR}:��11?N�I S I�OR FLO\V CON I�ROL, CO�1V1=,1'ANCf�:,AIvD��"(� 1��1CILI�CIES NO. 3- DETENTION TANKS AND VAULTS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Site Trash and debris Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site. per 1,000 square feet(this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual e�idence of dumping. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented rf appropriate. No contaminants present other than a surface oil film. Grasslgroundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Tank or Vault Trash and debris Any trash and debris accumulated in vault or tank No trash or debris in vault. Storage Area (includes floatables and non-floatables). Sediment Accumulated sediment depth exceeds 10%of the All sediment removed from storage accumulation diameter of the storage area for'/=length of area. storage vault or any point depth exceeds 15°/a of diameter. Example:72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than Y�length of tank. Tank Structure Plugged air vent Any blockage of the vent. Tank or vault freely vents. Tank bent out of Any part of tank/pipe is bent out of shape more Tank repaired or replaced to design. shape than 10%of its design shape. Gaps between A gap wider than'/rinch at the joint of any tank No water or soil entering tank sections,damaged sections or any evidence of soil particles entering through joints or walls. joints or cracks or the tank at a joint or through a wall. tears in wall Vault Structure Damage to wall, Cracks wider than Y2-inch,any evidence of soil Vauft is sealed and structurally frame,bottom,and/or entering the structure through cracks or qualified sound. top slab inspection personnel determines that the vault is not structurally sound. Inlet/Outlet Pipes Sediment Sediment filling 20%or more of the pipe. InleUoutlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleVoutlet No trash or debris in pipes. pipes(includes floatables and non-floatables). Damaged Cracks wider than'/rinch at the joint of the No cracks more than%.-inch wide at inleUoutlet pipes or any evidence of soil entering the joint of the inleUoutlet pipe. at the joints of the inleUoutlet pipes. 2009 Surface Water Design Manual—Appendix A 1 r'9I2009 A-� APPFVD[X n �4AINTENANCr REQUIlZi;�iG�TS PLOW CONTROL, CONVEYANCG,A�ID Vb'Q P�ICILITIES NO. 3-DETENTION TANKS AND VAULTS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Access Manhole Cover/lid not in place Cover/lid is missing or only partialty in place. Manhole access covered. Any open manhole requires immediate maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. not working maintenance person with proper tools.Bolts cannot be seated. Self-locking cover/lid does not work. Covedlid difficult to One maintenance person cannot remove CoveNlid can be removed and remove cover/lid after applying 80 Ibs of lift. reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs,misalignment, rust,or cracks. Ladder meets design standards. Atlows maintenance person safe access. Large access Damaged or difficult Large access doors or plates cannot be Replace or repair access door so it doors/plate to open opened/removed using normal equipment. can opened as designed. Gaps,doesn't cover Large access doors not flat and/or access Doors close flat and covers access completely opening not completely covered. opening completely. Lifting Rings missing, Lifting rings not capable of lifting weight of door Lifting rings sufficient to lift or rusted or plate. remove door or plate. 1/9/2009 2009 Surface��'ater Design Manual—Appendix A A-6 APPENDIX A MAINTENANCE REQUIREM�N7'S FOR I�LO��'CON"CI20L,COVVEYANCE,AtiD\��Q 1'�1CILITIES NO. 4-CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Structure Trash and debris Trash or debris of more than'/cubic foot which No Trash or debris blocking or is located immediately in front of the structure potentiaily blocking entrance to opening or is btocking capacity of the structure by structure. more than 10%. Trash or debris in the structure that exceeds'/3 No trash or debris in the structure. the depth from the bottom of basin to invert the lowest pipe into or out of the basin. Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Sediment Sediment exceeds 60%of the depth from the Sump of structure contains no bottom of the structure to the invert of the lowest sediment. pipe into or out of the structure or the bottom of the FROP-T section or is within 6 inches of the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section. Damage to frame Corner of frame extends more than'/.inch past Frame is even with curb. and/or top slab curb face into the street(If applicable). Top slab has holes larger than 2 square inches or Top slab is free of holes and cracks. cracks wider than%.inch. Frame not sitting flush on top slab,i.e., Frame is sitting flush on top slab. separation of more than'/.inch of the frame from the top slab. Cracks in walls or Cracks wider than'/:inch and longer than 3 feet, Structure is sealed and structurally bottom any evidence of soil particles entering structure sound. through cracks,or maintenance person judges that structure is unsound. Cracks wider than'/z inch and longer than 1 foot No cracks more than'/4 inch wide at at the joint of any inleUoutlet pipe or any evidence the joint of inlet/outlet pipe. of soil particles entering structure through cracks. SettlemenU Structure has settled more than 1 inch or has Basin replaced or repaired to design misalignment rotated more than 2 inches out of alignment. standards. Damaged pipe joints Cracks wider than'/rinch at the joint of the No cracks more than%.-inch wide at inleUoutlet pipes or any evidence of soil entering the joint of inleUoutlet pipes. the structure at the joint of the inleUoutlet pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Ladder rungs missing Ladder is unsafe due to missing rungs, Ladder meets design standards and or unsafe misalignment, rust,cracks,or sharp edges. allows maintenance person safe access. FROP-T Section Damage T section is not securety attached to structure T section securely attached to wall wall and outlet pipe structure should support at and outlet pipe. least 1,000 Ibs of up or down pressure. Structure is not in upright position(aliow up to Structure in correct position. 10%from plumb). Connections to outlet pipe are not watertight or Connections to outlet pipe are water show signs of deteriorated grout. tight;structure repaired or replaced and works as designed. Any holes—other than designed holes—in the Structure has no holes other than structure. designed holes. Cleanout Gate Damaged or missing Cleanout gate is missing. Replace cleanout gate. 2009 Surface Water Design Alanual–Appendix A 1 i 9,�2009 A-7 APPENDIX A NIAINTEN.AI�ICE REQUIRENiENTS FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 4-CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Cleanout gate is not watertight. Gate is watertight and works as designed. Gate cannot be moved up and down by one Gate moves up and down easily and maintenance person. is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Orifice Plate Damaged or missing Control device is not working properly due to Plate is in place and works as missing,out of place,or bent orifice plate. designed. Obstructions Any trash,debris,sediment,or vegetation Plate is free of all obstructions and blocking the plate. works as designed. Overflow Pipe Obstructions Any trash or debris blocking(or having the Pipe is free of all obstructions and , potential of blocking)the overflow pipe. works as designed. Oeformed or damaged Lip of overflow pipe is bent or deformed. Overflow pipe does not allow lip overflow at an elevation lower than design InIeUOutlet Pipe Sediment Sediment filling 20°/a or more of the pipe. InleUoutlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. � pipes(includes floatables and non-floatables). � Damaged Cracks wider than'/2-inch at the joint of the No cracks more than '/.-inch wide at i inleUoutlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. � at the joints of the inleUoutlet pipes. I Metal Grates Unsafe grate opening Grate with opening wider than'/8 inch. Grate opening meets design � (If Applicable) standards. Trash and debris Trash and debris that is blocking more than 20°/a Grate free of trash and debris. of grate surface. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s)of the grate. Grate is in place and meets design standards. Manhole Cover/Lid Covedlid not in place Cover/lid is missing or only partially in place. Cover/lid protects opening to Any open structure requires urgent structure. maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. Not Working maintenance person with proper tools.Bolts cannot be seated. Self-locking cover/lid does not work. CoverAid difficult to One maintenance person cannot remove Covedlid can be removed and Remove co�edlid after applying 80 Ibs.of lift. reinstalled by one maintenance person. 1i9.�2009 2009 Surface�'L'ater Design Manual—Appendix A A-8 APPENDIX A AIAINTENANCE REQUIREn�IENTS FOR FLO�V CONTROL,CONVI;YANCE,A\D\�1'Q f'ACILIT[ES NO. 5-CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Resuits Expected When Component Maintenance is Performed Structure Sediment Sediment exceeds 60%of the depth from the Sump of catch basin contains no bottom of the catch basin to the invert of the sediment. lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Trash and debris Trash or debris of more than'/:cubic foot which No Trash or debris blocking or is located immediately in front of the catch basin potentially blocking entrance to opening or is blocking capacity of the catch basin catch basin. by more than 10%. Trash or debris in the catch basin that exceeds No trash or debris in the catch basin. '/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within catch basin. gases(e.g.,methane). Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Damage to frame Corner of frame extends more than'/.inch past Frame is even with curb. and/or top slab curb face into the street(If applicable). Top slab has holes larger than 2 square inches or Top slab is free of holes and cracks. cracks wider than Y<inch. Frame not sitting flush on top slab, i.e., Frame is sitting flush on top slab. separation of more than'/.inch of the frame from the top slab. Cracks in walls or Cracks wider than'/z inch and longer than 3 feet, Catch basin is sealed and bottom any evidence of soil particles entering catch structurally sound. basin through cracks,or maintenance person judges that catch basin is unsound. Cracks wider than Y:inch and longer than 1 foot No cracks more than'/,inch wide at at the joint of any inleUoutlet pipe or any evidence the joint of inlet/outlet pipe. of soil particles entering catch basin through cracks. SettlemenU Catch basin has settled more than 1 inch or has Basin replaced or repaired to design misalignment rotated more than 2 inches out of alignment. standards. Damaged pipe joints Cracks wider than'/rinch at the joint of the No cracks more than%.-inch wide at inleUoutlet pipes or any evidence of soil entering the joint of inlet/outlet pipes. the catch basin at the joint of the inlet/outlet pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. InIeUOutlet Pipe Sediment Sediment filling 20%or more of the pipe. InleUoutiet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleUoutlet No trash or debris in pipes. pipes(includes floatables and non-floatables). Damaged Cracks wider than Yrinch at the joint of the No cracks more than%<-inch wide at inleUoutlet pipes or any evidence of soil entering the joint of the inleUoutlet pipe. at the joints of the inleUoutlet pipes. 2009 Surface Water Design Manual—Appendix A 1/9/2009 A-9 APPEI`TDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 5-CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Metal Grates Unsafe grate opening Grate with opening wider than'/B inch. Grate opening meets design (Catch Basins) standards. Trash and debris Trash and debris that is blocking more than 20% Grate free of trash and debris. of grate surface. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s)of the grate. Grate is in place and meets design Any open structure requires urgent standards. maintenance. Manhole CoverlLid Cover/lid not in place Cover/lid is missing or only partially in place. Cover/lid protects opening to Any open structure requires urgent structure. maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. Not Working maintenance person with proper tools.Bolts cannot be seated. Self-locking cover/lid does not work. Cover/lid difficult to One maintenance person cannot remove CoverAid can be removed and Remove cover/lid after applying 80 Ibs.of lift. reinstalled by one maintenance person. 1/9/2009 2009 Surface«%ater Design Alanual—Appendix A A-10 APPENDIX A MAINTENAI�'CE REQUIREMENTS FOR FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES � NO. 6-CONVEYANCE PIPES AND DITCHES I' Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When I Component Maintenance is Performed ' Pipes Sediment&debris Accumulated sediment or debris that exceeds Water flows freely through pipes. accumulation 20%of the diameter of the pipe. Vegetation/roots Vegetation/roots that reduce free movement of Water flows freely through pipes. � water through pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented'rf appropriate. No contaminants present other than a surface oil film. Damage to protective Protective coating is damaged;rust or corrosion Pipe repaired or replaced. � coating or corrosion is weakening the structural integrity of any part of � pipe. I Damaged Any dent that decreases the cross section area of Pipe repaired or replaced. ' pipe by more than 20%or is determined to have weakened structural integrity of the pipe. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20%of the Ditch cleaned/flushed of all sediment accumulation design depth. and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable j public. regulations. No danger of noxious I vegetation where County personnel or the public might normally be. ' Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Vegetation Vegetation that reduces free movement of water Water flows freely through ditches. through ditches. Erosion damage to Any erosion observed on a ditch slope. Slopes are not eroding. slopes Rock lining out of One layer or less of rock exists above native soil Replace rocks to design standards. place or missing(If area 5 square feet or more,any exposed native Applicable) soil. \ 2009 Surface Water Design Manual—Appendix A 1/9/2009 A-11 �1PPENDII,a I�fAINTENANCE REQUIREti1F,�ITS FLO«'CO.\"TROL,CONVE�'�\1�CE,AND��'Q I'ACILITI�S NO. 9- FENCING Maintenance Defect or Problem Conditions When Maintenance is Needed Results E�cpected When Component Maintenance is Performed Site Erosion or holes Erosion or holes more than 4 inches high and 12- No access under the fence. under fence 18 inches wide permitting access through an opening under a fence. Wood Posts, Boards Missing or damaged Missing or broken boards,post out of plumb by No gaps on fence due to missing or and Cross Members pa�ts more than 6 inches or cross members broken broken boards,post plumb to within 1'/:inches,cross members sound. Weakened by rotting Any part showing structural deterioration due to All parts of fence are structurally or insects rotting or insect damage sound. Damaged or failed Concrete or metal attachments deteriorated or Post foundation capable of post foundation unable to support posts. supporting posts even in strong wind. Metal Posts, Rails Damaged parts Post out of plumb more than 6 inches. Post plumb to within 1'/inches. I and Fabric Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence(including post,top rails,and Fence is aligned and meets design fabric)more than 1 foot out of design alignment. standards. Missing or loose tension wire. Tension wire in place and holding fabric. Deteriorated paint or Part or parts that have a rusting or scaling Structurally adequate posts or parts protective coating condition that has affected structural adequacy. with a uniform protective coating. Openings in fabric Openings in fabric are such that an 8-inch Fabric mesh openings within 50%of diameter ball could fit through. grid size. 1/9/2009 2009 Surface Water Design Manual—Appendix A A-14 APPE\DIX A I�fAINTENANCE REQUIREh4ENTS FOR FLOW CONTROL,CONVEYAI�'CE,AND WQ FACILITIES NO. 10-GATES/BOLLARDS/ACCESS BARRIERS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Chain Link Fencing Damaged or missing Missing gate. Gates in place. Gate members Broken or missing hinges such that gate cannot Hinges intact and lubed.Gate is be easily opened and closed by a maintenance working freely. person. Gate is out of plumb more than 6 inches and Gate is aiigned and vertical. more than 1 foot out of design alignment. Missing stretcher bar,stretcher bands,and ties. Stretcher bar,bands,and ties in place. Locking mechanism Locking device missing,no-functioning or does Locking mechanism prevents does not lock gate not link to all parts. opening of gate. Openings in fabric Openings in fabric are such that an 8-inch Fabric mesh openings within 50%of diameter ball could fit through. grid size. Bar Gate Damaged or missing Cross bar does not swing open or closed,is Cross bar swings fully open and cross bar missing or is bent to where it does not prevent closed and prevents vehicle access. vehicle access. Locking mechanism Locking device missing, no-functioning or does Locking mechanism prevents does not lock gate not link to all parts. opening of gate. Support post Support post does not hold cross bar up. Cross bar held up preventing vehicle damaged access into facility. , Bollards Damaged or missing Bollard broken,missing,does not fit into support No access for motorized vehicles to �I hole or hinge broken or missing. get into facility. � Does not lock Locking assembly or lock missing or cannot be No access for motorized vehicles to ' attached to lock bollard in place. get into facility. Boulders Dislodged Boulders not located to prevent motorized vehicle No access for motorized vehicles to access. get into facility. Circumvented Motorized vehicles going around or between No access for motorized vehicles to boulders. get into facility. 2009 Surface�'1'ater Design I�Ianual—Appendiz A 1/9/2009 A-15 APPENDIX A MAINTENAIv'CE REQUIREMENTS FLOW CONTROL,CONVEYANCE,AND�'�'Q FACILITTES NO. 11 -GROUNDS (LANDSCAPING) I Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed ' Site Trash or litter Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site. per 1,Q00 square feet(this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Trees and Shrubs Hazard Any tree or limb of a tree identified as having a No hazard trees in facility. potential to fall and cause property damage or threaten human life. A hazard tree identified by a qualified arborist must be removed as soon as possible. Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than 5% broken which affect more than 25°/o of the total of total foliage with split or broken foliage of the tree or shrub. limbs. Trees or shrubs that have been blown down or No blown down vegetation or knocked over. knocked over vegetation. Trees or shrubs free of injury. Trees or shrubs which are not adequately Tree or shrub in piace and supported or are Ieaning over,causing exposure adequately supported;dead or of the roots. diseased trees removed. 1/9/2009 2009 Surface Water Design Manual—Appendix A A-16 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 12-ACCESS ROADS Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is PerFormed Site Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway drivable by maintenance square feet(i.e.,trash and debris would fiil up vehicles. one standards size garbage can). Debris which could damage vehicle tires or Roadway dri�able by maintenance prohibit use of road. vehicles. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicabie regulations. I�i Source control BMPs implemented if � appropriate. No contaminants present other than a surface oil film. Blocked roadway Any obstruction which reduces clearance above Roadway overhead clear to 14 feet road surface to less than 14 feet. high. Any obstruction restricting the access to a 10-to At least 12-foot of width on access 12 foot width for a distance of more than 12 feet road. �� or any point restricting access to less than a 10 ' foot width. ' Road Surface Erosion,settlement, Any surface defect which hinders or prevents Road drivable by maintenance potholes,soft spots, maintenance access. vehicles. ruts Vegetation on road Trees or other vegetation prevent access to Maintenance vehicles can access surface facility by maintenance vehicles. facility. Shoulders and Erosion Erosion within 1 foot of the roadway more than 8 Shoulder free of erosion and Ditches inches wide and 6 inches deep. matching the surrounding road. Weeds and brush Weeds and brush exceed 18 inches in height or Weeds and brush cut to 2 inches in hinder maintenance access. height or cleared in such a way as to allow maintenance access. Modular Grid Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of Pavement pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damaged or missing Access surface compacted because of broken on Access road surface restored so missing modular block. road infiltrates. 2009 Surface�'�'ater Design nlanual—Appendix A I/9/2009 A-17 APPENDIX A MAINTENANCE REQUIREMENTS FLOVV CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 21 -STORMFILTER (CARTRIDGE TYPE) Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Site Trash and debris Any trash or debris which impairs the function of Trash and debris removed from the facility. facility. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oils,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Life cycle System has not been inspected for three years. Facility is re-inspected and any needed maintenance performed. Vault Treatment Sediment on vault Greater than 2 inches of sediment. Vault is free of sediment. Area floor Sediment on top of Greater than'/2 inch of sediment. Vault is free of sediment. cartridges Multiple scum lines Thick or multipie scum lines above top of Cause of piugging corrected, above top of cartridges. Probably due to plugged canisters or canisters replaced if necessary. cartridges underdrain manifold. Vault Structure Damage to wall, Cracks wider than Yrinch and any evidence of Vault replaced or repaired to design Frame,Bottom,andlor soil particles entering the structure through the specifications. Top Slab cracks,or quaiified inspection personnel determines the vault is not structurally sound. BafFles damaged BafFles corroding,cracking warping,and/or Repair or replace baffles to showing signs of failure as determined by specification. maintenance/inspection person. Filter Media Standing water in 9 inches or greater of static water in the vault for No standing water in vault 24 hours vault more than 24 hours following a rain event and/or after a rain event. overflow occurs frequently. Probably due to plugged filter media, underdrain or outlet pipe. Short circuiting Flows do not properly enter filter cartridges. Flows go through filter media. Underdrains and SedimenUdebris Underdrains or clean-outs partially plugged or Underdrains and clean-outs free of Clean-Outs filled with sediment and/or debris. sediment and debris. InIeUOutlet Pipe Sediment Sediment filling 20%or more of the pipe. InleUoutiet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleUoutlet No trash or debris in pipes. pipes(includes floatables and non-floatables). Damaged Cracks wider than'/2-inch at the joint of the No cracks more than'/<-inch wide at inleUoutiet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the iniet/outlet pipes. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Manhole access covered. Any open manhole requires immediate maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. not working maintenance person with proper tools.Bolts cannot be seated. Self-locking cover/lid does not work. Cover/lid difficult to One maintenance person cannot remove Cover/lid can be removed and remove covedlid after applying 80 Ibs of lift. reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs,misalignment, rust,or cracks. Ladder meets design standards. Allows maintenance person safe access. I Large access Damaged or difficult Large access doors or plates cannot be Replace or repair access door so it doors/plate to open opened/removed using normal equipment. can opened as designed. 1!9/2009 2009 Surface��'ater Design Manual—Appendix A A-30 APPE\DIX A MAI�ITENANCE REQUIREMENTS FOR FLOW CONTROL,COI�'VEYANCE,AND WQ FACILITIES NO. 21 -STORMFILTER (CARTRIDGE TYPE) Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Gaps,doesn't cover Large access doors not flat andlor access Doors ciose flat and cover access completeiy opening not completely covered. opening completely. Lifting Rings missing, Lifting rings not capable of lifting weight of door Lifting rings sufficient to lift or rusted or plate. remove door or plate. 2009 Surface Water Desian i�4anual—Appendix r1 1/9/2009 � A-31 ' A��►�TCAV'� � Important: Inspection should be performed by a person who is sii��;��n mesm�mwa�e�raz��e�„em L familiar with the StormFilter treatment unit. srow�wAr�R Sto rm Fi Iter° SOLUTIONS.� 1.If applicable, set up safety equipment to protect and notify surrounding vehicle and pedestrian traffic. itormFilter 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 I is occurring, note the flow of water per drainage pipe. Record I 1. Inspection: Determine the need for maintenance. all observations. Digital pictures are valuable for historical 2. Maintenance: Cartridge replacement and sediment removal. documentation. Inspection and Maintenance Activity 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 construction, 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 �, Sediment loading on the vault floor. If>4"of accumulated �nspection/maintenance activity schedule depending on the actual sediment,then go to maintenance. �perating 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�vhen flows into the system are unlikely. 3. Submerged cartridges. If>4"of static water in the cartridge Maintenance Activity Frequency bay for more that 24 hrs after end of rain event,then go to Maintenance 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 >_ 1/4" 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. severely 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 �ipes. If this is the case,then maintenance is warranted and the bypass is plugged. 3rtridges need to be replaced. Maintenance Warning: In the case of a spill, the worker should abort inspection 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 CONTECH immediately. To conduct an inspection: i 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 weather. It may '�e necessary to plug the filter inlet pipe if base flow is occurring. B• Unscrew the cartridge cap. 3eplacement 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. �ontinue steps a through E until all cartridges have been I S. 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 removed, 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 PV�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. Aethod 1: a. If desired, apply a light coating of FDA approved silicon A. This adivity will require that workers enter the vault to lube to the outside of the exposed portion of 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 con�enient spot beneath the vault access. 10. Using the vacuum truck boom, crane, or tripod, lower and Using appropriate hoisting equipment, attach a cable from �nstall 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. 12. Remove safety equipment. Important: Cartridges containing leaf inedia (CSF)do not �3. 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 C 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�vaste residuals. 'J2007 CONTECH Stormwater Solutions 800.925.5240 contech sto rmwater.com 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 product(s)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,D27,639;6,350,374;6,406,218;6,641,720;6,511,595;6,649,048;6,991,114;6,998,038;7,186,058;related foreign patents or other patents pending. � APPENDIX "D" CSWPPP I'� ,I �,2015 D. R. STRONG Consulting Enoineers Inc. Maertins Ranch Page 53 Technical Information Report City of Renton STORMWATER POLLUTION PREVENTION PLAN For MAERTINS RANCH Prepared For Albacore - ACH, LLC 9675 SE 36th Street, Suite 105 Mercer Island, WA 98040 206-588-1147 Owner Developer Operator/Contractor Albacore — ACH, LLC Albacore — ACH, LLC C.C. Edwards Construction, Inc. 9675 SE 36th Street, Suite 105 9675 SE 36th Street Suite 105 2415 Inter Ave. Mercer Island, Washington Mercer Island, Washington Puyallup, Washington 98372 98040 98040 Project Site Location 1508 Ilwaco Avenue NE, Renton, Washington Certified Erosion and Sediment Control Lead Earth Solutions NW, LLC ' 425.284.3300 SWPPP Prepared By D.R. Strong Consulting Engineers, Inc. 620 7th Avenue Kirkland, Washington 98033 ' Maher A. Joudi, P.E., Principal , SWPPP Preparation Date ', March 16, 2015 I Approximate Project Construction Dates Start Date: 06/01/2015 End Date: 10/30/2015 v 2015 D. R.STRONG Consulting Engineers Inc. STORMWATER POLLUTION PREVENTION PLAN TABLE OF CONTENTS , 1.0 INTRODUCTION....................................................................................................... 1 � 2.0 SITE DESCRIPTION................................................................................................. 3 2.1 Existing Conditions ........................................................................................... 3 2.2 Proposed Construction Activities ...................................................................... 3 3.0 CONSTRUCTION STORMWATER BMPS............................................................... 6 3.1 The 12 BMP Elements...................................................................................... 6 3.1.1 Element#1 — Mark Clearing Limits............................................................ 6 3.1.2 Element#2 — Establish Construction Access............................................. 6 3.1.3 Element#3 — Control Flow Rates .............................................................. 7 3.1.4 Element#4 — Install Sediment Controls..................................................... 7 3.1.5 Element#5 — Stabilize Soils ...................................................................... 8 3.1.6 Element#6 — Protect Slopes ..................................................................... 9 3.1.7 Element#7 — Protect Drain Inlets ............................................................ 10 3.1.8 Element#8 — Stabilize Channels and Outlets.......................................... 10 3.1.9 Element#9 — Control Pollutants .............................................................. 11 3.1.10 Element#10 — Control Dewatering .......................................................... 12 3.1.11 Element#11 — Maintain BMPs................................................................. 12 3.1.12 Element#12 — Manage the Project.......................................................... 12 3.2 Site Specific BMPs.......................................................................................... 14 3.3 Additional Advanced BMPs............................................................................. 14 4.0 CONSTRUCTION PHASING AND BMP IMPLEMENTATION ............................... 15 5.0 POLLUTION PREVENTION TEAM ........................................................................ 16 5.1 Roles and Responsibilities.............................................................................. 16 5.2 Team Members............................................................................................... 16 6.0 SITE INSPECTIONS AND MONITORING.............................................................. 17 6.1 Site Inspection ................................................................ ................................ 17 6.1.1 Site Inspection Frequency ....................................................................... 17 6.1.2 Site Inspection Documentation ................................................................ 17 6.2 Stormwater Quality Monitoring........................................................................ 18 6.2.1 Turbidity Sampling......................................................................................... 18 6.2.2 pH Sampling.................................................................................................. 18 6.2.3 Temperature Monitoring........................................................................... 19 7.0 REPORTING AND RECORDKEEPING.................................................................. 20 7.1 Recordkeeping................................................................................................ 20 7.1.1 Site Log Book .......................................................................................... 20 7.1.2 Records Retention ................................................................................... 20 O 2015 D. R.STRONG Consufting Engineers Inc. Page i of ii Stormwater Pollution Prevention Plan Maertins Ranch March 16.2015 7.1.3 Access to Plans and Records.................................................................. 20 7.1.4 Updating the SWPPP............................................................................... 20 7.2 Reporting ........................................................................................................ 21 7.2.1 Discharge Monitoring Reports ................................................................. 21 7.2.2 Notification of Noncompliance ................................................................. 21 7.2.3 Permit Application and Changes.............................................................. 21 Appendices AppendixA — Site Plan..................................................................................................22 Appendix B — Construction BMPs ................................................................................. 23 Appendix C —Alternative BMPs .................................................................................... 24 Appendix D — General Permit........................................................................................ 25 Appendix E — Site Inspection Forms (And Site Log)...................................................... 26 Appendix F — Engineering Calculations......................................................................... 33 A endix A Site Plan pp • 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... ;>2015 D. R. STRONG Consultin En ineers Inc. I'I g g Pageuofu Stormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 Stormwater Pollution Prevention Plan 1 .0 INTRODUCTION This Stormwater Pollution Prevention Plan (SWPPP) has been prepared as part of the NPDES stormwater permit requirements for the Maertins Ranch residential project located in Renton, Washington. The site is located at 1508 Ilwaco Avenue NE, Renton, Washington. The proposed development consists of the construction of 13 single-family dwelling units, roadway improvements, stormwater detention facility, and landscaping on 4.079 acres. 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 recordkeeping that will be implemented during the proposed construction project. The objectives of the SWPPP are to: 1. Implement Best Management Practices (BMPs) to prevent erosion and sedimentation, and to identify, reduce, eliminate or prevent stormwater contamination and water pollution from construction activity. 2. Prevent violations of surface water quality, ground water quality, or sediment management standards. 3. Prevent, during the construction phase, adverse water quality impacts including impacts on 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 July 2, 2005. 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 (SWMMWW 2004). , • 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. O 2015 D. R.STRONG Consulting Engineers Inc. Page 1 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 ' Stormwater Pollution Prevention Plan I • 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 — RECORDKEEPING. This section describes the requirements for documentation of the BMP implementation, site inspections, monitoring results, and changes to the implementation of certain BMPs due to site factors experienced during construction. Supporting documentation and standard forms are provided in the following Appendices: Appendix A— Site plans Appendix B — Construction BMPs Appendix C —Alternative Construction BMP list Appendix D — General Permit Appendix E — Site Log and Inspection Forms Appendix F — Engineering Calculations ;:2015 D. R.STRONG Consulting Engineers Inc. Page 2 of 44 I Stormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 �I Stormwater Pollution Prevention Plan 2.0 SITE DESCRIPTION 2.1 Existing Conditions Total existing Site area is approximately 177,683 s.f. (4.079 ac). Total proposed Project area is 177,683 s.f. (4.079 ac). The Parcel is currently developed with one single-family residence, garage, barn and a gravel driveway. The remainder of the Site is pasture, scotch broom, and scattered trees. The 4.079 acre parcel is situated on a slope that discharges runoff to the northeast and southwest. However, upon further field inspection it appears that the high point is a consequence of prior Site grading to create buildings pads for the existing garage and barn on the Site. Therefore, for purposes of this analysis, the Site will be considered to be within one TDA and all runoff will be conveyed to the northeast. For the purpose of hydrologic calculations, the entire Site is modeled as till forest. 2.2 Proposed Construction Activities The applicant is seeking approval to create 13 lots with lot sizes ranging from approximately 8,050 s.f. to 10,985 s.f. All existing improvements will be demolished or removed during plat construction. The 13 single-family residences combined with their driveways (includes turn around easement) will create approximately 55,562 s.f. (1.28 ac) of impervious area. The proposed 53-foot right of way will be improved with 26 feet of pavement, vertical curb, gutter, 8-foot planter strip and 5-foot sidewalk. The half street frontage improvements on NE 16th Street will consist of 11.5 to15.5 feet of new pavement (27.5' total pavement width west of the proposed road intersection with NE 16th Street and 37' total pavement width east of the i ntersection), 1,600' of vertical curb, gutter, 8-foot planter strip and a 5-foot sidewalk. The improvements from right-of ways will add approximately 41,603 s.f. (0.95 ac) of impervious surFace. The Project will result in a total of 2.32 ac of new impervious surfaces. The remainder of the developed Site (1.76 ac) will consist of landscaping and lawns. Approximately 3,100 s.f. will bypass the facility (900 sf impervious, 2200 pervious) due to topographic constraints. This area meets the requirements of Section 1.2.3.2.E of the Manual with a 100-year peak of 0.024 cfs. The runoff converges with the discharge of the facility almost immediately and will not create an adverse downstream impact. , Facility design will provide compensatory storage such that the predeveloped discharge rates are not exceeded at the downstream point of compliance. Per the 2009 King County Surface Water Design Manual (Manual), Appendix C, each lot within a new subdivision is required to mitigate for impervious surface area equal to 10% of the lot area. Per Figure C.1.3.A, Flow Control BMP Flowchart, the Project will , utilize Basic Dispersion with the use of splash blocks. Two splash blocks mitigating a total of 1,400 s.f. of impervious area, will be installed with each residence. This shall � mitigate for 14.22% to 15.30% of impervious area for each lot, thus accommodating flow control BMP requirements. See table below for lot area and percent impervious mitigated per lot. O 2015 D. R.STRONG Consulting Engineers Inc. Page 3 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 Stormwater Pollution Prevention Plan ROOF AREA ROUTED TO SPLASH BLOCK PERCENT IMPERVIOUS LOT N0. LOT AREA{S.F.) (700 S.F./1 SPLASH BLOCK) MITIGATED 1 9848 1400 14.22 2 8050 1400 17.39 3 8075 1400 17.34 4 10985 1400 12.74 5 9311 1400 15.04 6 11731 1400 11.93 7 9982 1400 14.03 8 9982 1400 14.03 9 10073 1400 13.90 10 10769 1400 13.00 11 8115 1400 17.25 12 8050 1400 17.39 13 9150 1400 15.30 The Project is required to provide Level 2 Flow Control and Basic Water Quality treatment, per the 2009 KCSWDM (Manual). All surface water runoff from impervious surfaces will be collected and conveyed to a storm detention vault followed by a storm filter located in Tract "A". The facility will be sized using 4,000 s.f. of impervious area per lot per section 3.2.2. No flow control credit was taken for the use of splash blocks with regard to facility sizing. No restricted footprint credit is proposed. The following summarizes details regarding site areas: • Total site developable area: 4.079 acres • Percent impervious area before construction: 10.9 % • Percent impervious area after construction: 56.4 % • Disturbed area during construction: 3.90 acres • Disturbed area that is characterized as impervious (i.e., access roads, staging, parking): 0.36 acres TDA • 2-year stormwater runoff peak flow prior to construction (existing): 0.150 cfs • 10-year stormwater runoff peak flow prior to construction (existing): 0.260 cfs • 2-year stormwater runoff peak flow during construction: 0.838 cfs • 10-year stormwater runoff peak flow during construction: 0.982 cfs • 2-year stormwater runoff peak flow after construction: 0.074 cfs 3 2015 D. R.STRONG Consulting Engineers Inc. Page 4 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 Stormwater Pollution Prevention Plan • 10-year stormwater runoff peak flow after construction: 0.225 cfs All stormwater flow calculations are provided in Appendix F. �� 2015 D. R.STRONG Consulting Engineers Inc. Page 5 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 Stormwater Pollution Prevention Plan 3.0 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: • High Visibility Plastic or Metal Fence (BMP C103) The plastic fence will be placed around the perimeter of the developable area of the Site. BMP will be implemented at the start of construction. Alternate BMPs for marking clearing limits are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the 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 placed at the intersection of the proposed il "Road B" and 156th Avenue SE on the existing driveway. This BMP will be implemented at the start of construction. Construction Road and Parking Area Stabilization will occur along the road into the site and in staging areas where parking of equipment will occur. This will occur as the project goes along. Alternate construction access BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective �s-2015 D. R. STRONG Consulting Engineers Inc. Page 6 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16. 2015 Stormwater Pollution Prevention Plan 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: • Sediment Pond (Baker Tank to be utilized) and Detention Vault A Baker Tank will be utilized and to be used during construction until permanent detention vault bottom and walls are constructed. The vault outlet will be plugged and used for sediment storage during construction. 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. The project site is located west of the Cascade Mountain Crest. As such, the project j must comply with Minimum Requirement 7 (Ecology 2005). I, 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 I 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: • Silt Fence (BMP C233) • Storm Drain Inlet Protection (BMP C220) • Interceptor Swale (BMP C200) • Sediment Pond (BMP C241) • Detention Vault Silt fence will be installed around the perimeter of the Site in areas where runoff could sheet-flow offsite. This BMP will be installed at the start of construction. ��2015 D. R.STRONG Consulting Engineers Inc. Page 7 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 Stormwater Pollution Prevention Plan Storm Drain Inlet Protection will be installed on all newly constructed catch basins throughout the site as well as the existing catch basins in NE 16th Street. The existing catch basin protection will be installed at the start of construction, and protection for the newly constructed catch basins will occur as they are installed. The interceptor swales will be installed during site grading. A Baker Tank will be utilized for sedimentation at the commencement of construction. 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 si n that existing BMPs are ineffective or failing. 9 In addition, sediment will be removed from paved areas in and adjacent to construction work areas manually or using mechanical sweepers, as needed, to minimize tracking of sediments on vehicle tires away from the site and to minimize washoff of sediments from adjacent streets in runoff. 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 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. • 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: O 2015 D. R.STRONG Consulting Engineers Inc. Page 8 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 Stormwater Pollution Prevention Plan • Temporary and Permanent Seeding (BMP C120) ' • Plastic Covering (BMP C123) �� • Dust Control (BMP C140) I'' Permanent Seeding will occur as grading is completed. All stabilized sections will be �� seeded and vegetated. Plastic Covering will occur throughout the site as deemed necessary by the contractor and CESCL & COR inspector. Dust Control will occur throughout the site as deemed necessary by the contractor and CESCL & COR inspector. 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. The project site is located west of the Cascade Mountain Crest. As such, no soils shall remain exposed and unworked for more than 7 days during the dry season (May 1 to September 30) and 2 days during the wet season (October 1 to April 30). Regardless of the time of year, all soils shall be stabilized at the end of the shift before a holiday or weekend if needed based on weather forecasts. 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 than minimizes erosion. The following specific BMPs will be used to protect slopes for this project: • Temporary and Permanent Seeding (BMP C120) • Check Dams (BMP C207) Permanent Seeding will occur throughout the site as slopes arE- �'�'��!�.,�� Checks Dams will be installed every 50' as shown on the plan. Altemate slope protection BMPs are included in Appendix C as a qu�ck reierence tooi 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 O 2015 D. R.STRONG Consulting Engineers Inc. Page 9 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 Stormwater Pollution Prevention Plan 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 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 • Catch Basin Filters Storm Drain Inlet Protection will be installed on all newly constructed catch basins throughout the site as well as the existing catch basins in NE 16th Street. The existing catch basin protection will be installed at the start of construction, and protection for the newly constructed catch basins will occur as they are installed. The outlet catch basin in Tract A will also require a catch basin filter to be installed while the outFall system is being constructed for the detention pond. 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 implemented The project will not discharge to any outlets or channels; therefore no BMP's are req ui red. 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. The project site is located west of the Cascade Mountain Crest. As such, all temporary on-site conveyance channels shall be designed, constructed, and stabilized to prevent O 2015 D. R.STRONG Consulting Engineers Inc. Page 10 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 Stormwater Pollution Prevention Plan erosion from the expected peak 10 minute velocity of flow from a Type 1A, 10-year, 24- hour recurrence interval storm for the developed condition. Alternatively, the 10-year, 1- hour peak flow rate indicated by an approved continuous runoff simulation model, increased by a factor of 1.6, shall be used. Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent streambanks, slopes, and downstream reaches shall be provided at the outlets of all conveyance systems. 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 below. Vehicles, construction equipment, and/or petroleum product storage/dispensing: • 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. • On-site fueling tanks and petroleum product storage containers shall include secondary containment. • Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. • In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. • Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Demolition: • Dust released from demolished sidewalks, buildings, or structures will be controlled using Dust Control measures (BMP C140). • Storm drain inlets vulnerable to stormwater discharge carrying dust, soil, or debris will be protected using Storm Drain Inlet Protection (BMP C220 as described above for Element 7). • Process water and slurry resulting from sawcutting and surfacing operations will be prevented from entering the waters of the State by implementing Sawcutting and SurFacing Pollution Prevention measures (BMP C152). Concrete and grout: • Process water and slurry resulting from concrete work will be prevented from entering the waters of the State by implementing Concrete Handling measures (BMP C151). Sanitary wastewater: : 2015 D. R. STRONG Consulting Engineers Inc. Page 11 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16.2015 Stormwater Pollution Prevention Plan • Portable sanitation facilities will be firmly secured, regularly maintained, and emptied when necessary. Solid Waste: • Solid waste will be stored in secure, clearly marked containers. I Other: • Other BMPs will be administered as necessary to address any additional pollutant sources on site. 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. 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: , (West Response) As this project site is located west of the Cascade Mountain Crest, the '� project will be managed according to the following key project components: 'I C�2015 D. R.STRONG Consulting Engineers Inc. Page 12 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 Stormwater Pollution Prevention Plan Phasi ng of Construction • The construction project is being phased to the extent practicable in order to prevent soil erosion, and, to the maximum extent possible, the transport � of sediment from the site during construction. • Revegetation of exposed areas and maintenance of that vegetation shall be an integral part of the clearing activities during each phase of construction, per the Scheduling BMP (C 162). Seasonal Work Limitations • From October 1 through April 30, clearing, grading, and other soil disturbing activities shall only be permitted if shown to the satisfaction of the local permitting authority that silt-laden runoff will be prevented from leaving the site through a combination of the following: o Site conditions including existing vegetative coverage, slope, soil type, and proximity to receiving waters; and o Limitations on activities and the extent of disturbed areas; and o Proposed erosion and sediment control measures. • Based on the information provided and/or local weather conditions, the local permitting authority may expand or restrict the seasonal limitation on site disturbance. • The following activities are exempt from the seasonal clearing and grading limitations: 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 • 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 • 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: G 2015 D. R.STRONG Consulting Engineers Inc. Page 13 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16.2015 Stormwater Pollution Prevention Plan o Assess the site conditions and construction activities that could impact the quality of stormwater, and o Assess the effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. • A Certified Erosion and Sediment Control Lead shall be on-site or on-call at all times. • 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 implemented as soon as possible. Maintaining an Updated Construction SWPPP • This SWPPP shall be retained on-site or within reasonable access to the site. • 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. • The SWPPP shall be modified if, during inspections or in�estigations conducted by the owner/operator, or the COR inspector, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater 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 (7) days following the inspection. If 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. 3.2 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 „2015 D. R.STRONG Consulting Engineers Inc Page 14 of 44 Ii Stormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 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 I 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: 6/24/2015 • Estimate of Construction finish date: 10/30/2015 • Mobilize equipment on site: 6/24/2015 • Mobilize and store all ESC and soil stabilization products: 6/26/2015 • Install ESC measures: 6/26/2015 • Install stabilized construction entrance: 6/24/2015 • Begin clearing and grubbing: 6/28/2015 • Demolish existing buildings: 6/30/2015 - 7/14/2015 • Begin Site Grading: 7/1/2015 • Begin implementing soil stabilization and sediment control BMPs throughout the site: 7/1/2015 • End Site Grading: 7/30/2015 • Begin Utility Construction: 8/3/2015 • End Utility Construction: 8/14/2015 • Begin Paving and Sidewalk Installation: 9/14/2015 • Permanent erosion control measures (hydroseeding): 9/30/2015 • End Paving and Sidewalk Installation: 10/16/2015 • Final landscaping and planting begins: 10/19/2015 ��-2015 D. R.STRONG Consulting Engineers Inc. Page 15 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 � 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 Members Names and contact information for those identified as members of the pollution prevention team are provided in the following table. Title Name(s) Phone Number Certified Erosion and Sediment Control Earth Solutions NW,LLC 425.284.3300 Lead(CESCL) Resident Engineer Maher A.Joudi 425.827.3063 Emergency Ecology Contact NW Regional Office 425.649.7000 Emergency Owner Contact Justin Lagers 253.405.5587 Non-Emergency Ecology Contact Ken Waldo 425.649J279 Monitoring Personnel Earth Solutions NW,LLC 425.284.300 ��-2015 D. R.STRONG Consulting Engineers Inc. Page 16 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 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. The name and contact information for the CESCL is provided in Section 5 of this SWPPP. Site inspection will occur in all areas disturbed by construction activities and at all stormwater discharge points. Stormwater will be examined for the presence of suspended sediment, turbidity, discoloration, and oily sheen. The site inspector will evaluate and document the 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 Site inspections will be conducted at least once a week and within 24 hours following an equal or greater than 1/4" precipitation 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. All reports will � be submitted to COR plan reviewer. ; 2015 D. R STRONG Consulting Engineers Inc. Page 17 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16. 2015 Stormwater Pollution Prevention Plan 6.2 Stormwater Quality Monitoring The Site will discharge into an existing storm drainage system. Before project discharge leaves the Site, it enters a detention vault and water quality stormfilter before entering the existing conveyance system located within NE 16th Street. This will be sufficient in accommodating water quality requirements. Testing at the outlet will still occur as necessary. 6.2.1 Turbidity Sampling Sampling and monitoring will be conducted during the entire construction phase of the project. Samples will be collected daily at the downstream catch basin for both the Baker Tank and vault. If there is no flow in this catch basin, the attempt to sample will be recorded in the site log book and reported to Ecology in the monthly Discharge Monitoring Report (DMR) as "No Discharge". Samples will be analyzed for turbidity using the EPA 180.1 analytical method. The key benchmark turbidity value is 25 nephelometric turbidity units (NTU) for the downstream receiving water body. If the 25 NTU benchmark is exceeded in any sample collected from the tested catch basins, 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 modified BMPs in the SWPPP as necessary. 3. Sample discharge daily until the discharge is 25 NTU or lower. If the turbidity exceeds 250 NTU 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 sampling daily until the discharge is 25 NTU or lower Initiate additional treatment BMPs such as off-site treatment, infiltration, filtration and chemical treatment within 24 hours, and implement those additional treatment BMPs as soon as possible, but within a minimum of 7 days. 3. 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. 6.2.2 pH Sampling Sampling and monitoring for pH will occur during the phase of construction when concrete pouring will be conducted until fully cured (3 weeks from last pour) and discharges are documented to be below pH 8.5. Samples will be collected weekly at the sedimentation pond prior to discharge to surface water. Samples will be analyzed for pH using a calibrated pH meter and recorded in the site log book. The key benchmark pH value for stormwater is a maximum of 8.5. If a pH greater than 8.5 is measured in the sedimentation trap/pond(s) that has the potential to discharge to surface water, the following steps will be conducted: O 2015 D. R.STRONG Consufting Engineers Inc. Page 18 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 Stormwater Pollution Prevention Plan 1. Prevent (detain) all discharges from leaving the site and entering surface waters or storm drains if the pH is greater than 8.5 2. Implement CO2 sparging or dry ice treatment in accordance with Ecology BMP C252. Describe inspection results and remedial actions that are taken in the site log book and 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. O 2015 D.R.STRONG Consulting Engineers Inc. Page 19 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 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 convenience, 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 SS.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 u dated timeline for BMP im lementation will be re ared. P P p p : 2015 D. R. STRONG Consulting Engineers Inc. Page 20 of 44 Stormwater Pollution Prevention Plan MaeRins Ranch March 16.2015 Stormwater Pollution Prevention Plan 7.2 Reporting 7.2.1 Discharge Monitoring Reports Water quality sampling results will be submitted to Ecology monthly on Discharge Monitoring Report (DMR) forms in accordance with permit condition S5.B. If there was � no discharge during a given monitoring period, the form will be submitted with the words '�, "no discharge" entered in place of the monitoring results. If a benchmark was � exceeded, a brief summary of inspection results and remedial actions taken will be included. If sampling could not be performed during a monitoring period, a DMR will be ' submitted with an explanation of why sampling could not be performed. 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 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. Any time turbidity sampling indicates turbidity is 250 nephelometric turbidity units (NTU) 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 SS.A (see Section 5.0 of this SWPPP for contact information). 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. �2015 D. R.STRONG Consulting Engineers Inc. Page 21 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 Stormwater Pollution Prevention Plan APPENDIX A - SITE PLAN O 2015 D. R.STRONG Consulting Engineers Inc. Page 22 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 SE 1/4 SECTION 3, TOWNSHIP 23 N, RANGE 5 E, W.M. X �� X- � � � _ MAERTINS RANCH ; � ,� X . 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FUEL/NG NOTE.• L ' l E I�Y£R M/N 2 ` �y� I ��.- . �6.00'7FMPMMV � � C�OL ALW�N ALY'ORDANCE��tl1YS£ROSI�ESEA'MET/T C TRlM_STANOADIR�GUNCE I71E ER0.4WJ AND SEDMfNT ALL 7RUCX WJD EOUI�ENT FUE2JNG ON97E FU�STDR��STAKE PL10E C.O.R. piY CK RENTlYJ . , 3 I f - �1 �- STAC/NC ARfA NA N TRUCK NO A A CGNSIRVC710N JZ Cpy�p q(L pREAS MAT MRL BE UNMDRKED FOR MQPE THAN gVEN DAYS DURING THE ORY SfASGW OR 7M0 OATS OURWC 7N£NET 1 X �J � I I��-„ cas�uovr $[ASON MITH SRUI( NCGY!f78fR MULCN,COAIPOST,PLlST7C SHEE7/NG LY2£Of/IVAL£NT. FQUlPMEN T M A l N T E N A N C E I V O T E.' �F �xnca�eoArro r�c� .. �w n 1.2 STABIL/ZE ALL AREAS MAT REAQI FlNAL GRADE IMTiNN SE1£N DAYS - �i _ _}� � _ I � _ . 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H4�CCCURRE�I,A=F£CTm APE:S SH:.LI 6E CfiDIECTEJ 3Y RI:P:3�P Ni EROS�ON��Yiii�L BLINI�T. _ " -_ "- '- .:Jn"i_HCe.py�;AVSr.9LLB�PETIC.�EOI1J'.1=IXPtE_Y. 5. _ " ',+G'-_SRES..�P�,;=c1H_a.He.,�ryE�pHSTPVCTIONENIRnN."F15�F£NCRlGS-.4L6E ISONElRICVEN INSTc1_ED i0 a�Niv.E�lyP,�:FFIC.� I Tie6iGDeln,MxeEmltt�NG+nowMMry�trnfeaWEY9�F Frig�C �ioN.KS i STABILIZED SN.PI.AP-216.I0 mare.w�i:w�*�+�.��.�✓�eroo.m�w��m.�.a��a�,� ��!� D3PARPYE.VT , CONSTRUCTIONENTRANCE ypgCH 2O08 � rarta.�my,n.��„a�m.�.nna�.mysp.-�s�„eoi.y�s) M ; T SfD.PLLN-218.30 _ � '� �` PUELC 1YORKS CATCN BASIN FILTER �� FU3LIC NOP.h:S INTERCEPTORSWALE ��N-Zl�'�� 37D•PL1N-E17.40 - �, DEPAE2'['IdEN': �� PEPARSML+vT PC6LI�FJRKS GHECK DAMS SPACING AND ___ Y � . . �Po '-"�`m`�M1Ls9 � �RCH 2G09 •�� M?RC:'2008 .�:�� DEPA4TME`!T CROSS SECTIONS yp�CH 2O09 I I -_ - I �a.E�..� • - 7REE PROTEC770N MEASURES i I I -- - CONS7RUC71LW SiORAGE PROH/B/TED: TH£APPUCANT YAY NOT F1CL,EXCA✓ATE STAp( " - - QQ STOR£ANY£IXl1PA/EN7,OISPOSE Q�ANY MAIER/ALS,5(JPPL/£S 6Q FLVIOS,P°ERAIE ANY _ = - - �I - EOVIPNENT,INST.ILL/MP£RNCYIS SURFACE$OR CONPACT 1N£EMhI!N ANY WAY M07HM/iHE - - -- -��..7�-� ARE�DfFlNfD HY TNE ORlP LlNE OF ANY 7REE TD 9E REiA!ldD. ��I �� E� �� b. 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NO 57OCKPSUNG CF MATERULS, 444CUUR . !a•qosrt�c.nrx+wCrs��'�u�swnEuuacw;ro�carwsEr�sr:_�r - a�crasr 07'ICIAL IF 1H£MULC}I M]CL ADlERg1Y AFFECT PROIFCiFD CRtlY/ND C01kR PLAN75 ��C 6P SRMACE Oi£IXIIPMENT OR 441GYNERY SHALL '. �ncMcunv3a.coua�cvoaEr smFvcr.rne.aiCffcianaEnvxw.xt�H�rwarrs��aic�=e�icE� BEA[LOK£DINMMiFIELlMITQ�7N£FEHpNG _ �rvic�i.Eis'�ei i��s�'r_ oce=�ioa�eEs-�aTn�-��.�ov e.�sar-ne��_rrErvce g MLNPTOMNG REWIRm DURlNG CQVS7Rt/Ci7QV: THE APPL/CANT SNALL RETAMI A � �' t�aVcsec.v=_mamu+cHrr.rseai«s*�eF�cevoo�sw�ru oww ienr�o�swnssoa,�we.ETM=_s�r PRCfES51CWA1 ARBG415T PQ OTHfR IX/ALIf7£0 PROIfF5570NAL TO PRUNE BRANC7iE5 ANO �E n �E^��" R001$FfR7MIZE,AND WARF AS APPRGWlZiA7E FQ4 ANY 7R£ES AND GRPI/I1D COVER NMCH TREE PROTECTION D£TA1L u...Fn,��s,u+o�.�: .wE ro eF�w�a. a > R��,�o�o��°:'mE��°E E�:`E�d��s,TME�.,�E��'„�`;R�T�.s��,o�.�=. I .�,��u„�o=a�.�e.�,�,oTM_��,r�s�.��E.��oaA_�.E�-.E»� � Fr�EF��,�aF��_�-�,:�"�°"r��,."�o�=_"��.�,�,,�,�E,�_,,,,.�.sw,�sE�=a�E�. � IN COMPLIANCE WITH CITY OF RENTON � _ DRAWINGS NOT APPROVED sTnNo,aR�s I FOR CONSTRUCTION UNLESS Bv oate: t � sro.eur�-zt4.00 STAMPED OR SIGNED APPROVED Br oate: � � "� FceN',er��°erT 5"T FE"`E BY THE REVIEWING AGENCY BY: Date: � Fvt� I LL.kI'F:LU.B - BY: Date: a � ✓o•• �JIV �Y � �Pa '�'r��,l � �'. ; r, �ncvcs�.�.c � ��s Hmm ^��"'•°, �, CITY OF MAERTINS RANCH oi.zo.zois i _ cd z w«x:,�8 j�Bdws Yw� � � y x � D.R.STRONG °�iw � I CONSULTING ENG/NEERS � � R E N ' O N ��g� °"'""wuc i � T.E.S.C.NOTES AND DETAILS p Ulitiealkxierr�andLocetimCentx � � D � -"gjyW �� Pl��r:ng/B�ilc�ng/�ub'c Works Dep:. � lkx e � � aoMr,ro,oFtwn> s :. y' ,y�j•� �-��.�,,�•�•��, No. R�nsioN er �n-E aFPR P �.�.°.• PERMITS: U15-001308, 615-000196 OI2i@7.31763 F45d213lSd yy $ �20 DRS PROJECT N0. 14103 A -N N N N A A APPENDIX B — CONSTRUCTION BMPS High Visibility Plastic or Metal Fence (BMP C103) Stabilized Construction Entrance (BMP C105) Wheel Wash (BMP C106) Construction Road/Parking Area Stabilization (BMP C107) Temporary and Permanent Seeding (BMP C120) Mulching (BMP C121) Dust Control (BMP C140) Materials on Hand (BMP C150) Concrete Handling (BMP C151) Grass-Lined Channels (BMP C201) Pipe Slope Drains (BMP C204) Check Dams (BMP C207) Storm Drain Inlet Protection (BMP C220) Silt Fence (BMP C233) Temporary Sediment Pond (BMP C241) . .i r = -_ . : � - , _ , - , s-_ � � F � �� . ., �t�� ;:�� .� ��,- ��; �� r , � _ 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 alternati�e BMP needs to be implemented. Nets and Blankets (BMP C122) Plastic Covering (BMP C123) Sawcutting and Surface Pollution Prevention (BMP C152) Interceptor Dike and Swale (BMP C200) Brush Barrier (BMP C231) Gravel Filter Berm (BMP C232} Vegetated Strip (BMP C234) Straw Wattles (BMP C235) 2015 D. R STRONG Consulting Englneers Inc Page 24 of 44 S?ormwater Pollution Prevention Plan Maertlns Ranch March 16 2015 APPENDIX D - GENERAL PERMIT G 2015 D. R.STRONG Consulting Engineers Inc. Page 25 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16. 2015 . ��4,5TA7�g�� (. o b.. � l � x w�, y qz :, � . . a'S''[3864��Y STATE OF WASHINGTON � DFPARTMENT OF ECOL�GY PO Box 47600•Olympi� WA 98504-7600• 360-407-6000 711 for Washington Relay Service • Persons with a speech disability can cal!877-833-6341 May 4,2015 , Michael Gladstein ^ O PNW Holdi.ngs,LLC `j 9675 SE 36�'Street Mercer Island, WA 98040-3723 � � RE: Coverage under the Construction Stotmwater General Permit Pernnit number: WAR302860 Site Name: Maerlin's Ranch I.ocation: -150ii IIwaco�ve NE . Renton,WA County: King Disturbed Acres: 4.079 . Deaz Mr. Gladstein: The Washington State Department of Eeology(Ecology)received your Notice of Intent for coverage ' �u.nder Ecology's Constraction Stormwater General Permit(pemut). This is your permit coverage letter. Your permit coverage is effective on May 4, 2015: Please retai.n this permit coverage letter with your permit(enclosed), stormwater pollution prevention plan(SWPPP), and site log book. These materiais are the official record af permit coverage for p�ur site. Please take time to read the entire permit and contact Ecology if you have a.ny questions. Appeal Process � You have a right to appeal coverage under the general permit to the Pollution Control Hearing Board � (PCHB)withi.n 30 days of fihe date of receipt of this letter. Thzs appeal is limited to the general ; permit's applicability or non-applicability to a specific discharger..The appeal process is governed by chapter 43.21B RCW and chapter 371-OS WAC. "Date of recezpY'is defined in RCW 43.21B.001(2). °� i� f ( ( Mtchael Gladstein � May 4, 2015 .. Page 2 To appeal,you must do the following within 30 days of the date of receipt of this leiter: � File yozar appeal and a copy of the permit cover page with the PCHB {see addresses below). Filing means actual receipt by the PCHB during regulaz business hours. � Serve a copy of your appeal a.nd the permit cover page on Ecology in paper form- by mail or in person(see addresses below). E-mail is not accepted. � You must also comply with other applicable requirements in chapter 43.21B RCW and chapter 371- 08 WAC. . Address and�,ocation Information: Street Addxesses: Mailing Addresses: • Department of Ecology Department of Ecology Atta: Appeals Processing Desk Attn:Appeals Processing Desk 300 Desmond Drive SE PO Box 47608 Lacey,WA 98503 Olympia,WA 48504-7608 Poilution Control Hearings Boazd(PCHB} Pollutian Contr:,I Hcarings Bcard 11�1 Lsrael Road SW, Suite 301 PO Box 40943 Tumwater, WA 98501 Olympia, WA 98504-0903 Electronic Discharge Monitoring Reports (WQWebDMR) This permit requires that Pemnittees submit monthiy discharge monitoring reports(DMRs) electronically using Ecalogy's secure online system,WQWebDMR. To sign.up for WQ'WebDMR go to: www.ecy.wa.gov/programs/wq/permits/paris/webdmr_html. If you have questions, conta.c�the portal staff at(360)407-�097 (Oiyinpia area), or(800) 633-6193/option�3, or email WQWebPorta.�@ecy.wa.gov. Ecology Field Inspector Assistance If you have questions regardi.ng stormwater mauagement at your construction site,please contact Tracie Walters of F.cology's Northwest Regional Office in Bellewe at tracie.walters@ecy.wa.gov, or (42� 649-44$4. Questions or Additional Information Ecology is committed to providing assistance. Please review our web page at: www.ecy.wa.gov/programs/wq/stonnwaterlconstruction. If you have c�uestions ab�ut the construction stormwater general permit,plea.se conta,ct Clay Keown at clay.keown@ecy.wa.gov, or , (360)407-6048. Sincerely, Bill Moore,P.E.,Manager Program Development Services Section Water Quality Program Enclosure WAR302860 , MAERTINS RANCH KING COUNTY Issuance Date: December 1,2010 Effective Date: Jauuary 1,201 I Expiration Date: December 31,2015 ��1�!��J��tJ� A g�1�1 � 1 � �� A National Pollutant Dischazge Elimination System{NPDES) and State Waste Discharge General � Permit for Stormwater Discharges Associated with Construction Activity . S#ate of�Vashington � Department of Ecology � Olympia,Washington 98504 � In compliance with the provisions of . Chapter 90.48 Revised Code of Washington � . (State of Washington Water Pollution Control Act) • and Tifle 33 United_States Code,Section 1251 et seq. The Federal'Water Pollution Control Act('I'he Clean VJatier Act) Until this permit expires, is modified or revoked,Pernuttees that have properly obtained coverage under this general permit are authorized to discharge in•accordance with the special and general conditions that follow. �e�Susewi.nd,P.E.,P.G. VVater Quality Program Manager 'Washington State Deparhnent of Ecology J 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, turbid water, discoloration, and/or oil sheen shall be noted, as applicable. f. A description of any water quality monitoring performed during inspection, and the results of that monitoring. g. General comments and notes, including a brief description of any BMP 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 !� terms and conditions of the SWPPP and the NPDES permit. If the site �I 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'. �s^;2015 D. R. STRONG Consulting Engineers Inc. Page 26 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 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 health or the environment, the Permittee shall comply with the Noncompliance Notification requirements in Special Condition S5.F of the permit. ,I �2015 D. R. STRONG Consulting Engineers Inc. Page 27 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 SITE INSPECTION FORM General I nformation 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 Action BM P: I�I Inspected Functioning Location Y N Y N NIP Problem/Corrective Action II 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: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP C�2015 D. R.STRONG Consulting Engineers Inc. Page 28 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16. 2015 BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 4: Install 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: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: I Inspected Functioning Location Y N Y N NIP Problem/Corrective Action , I E/ement 5: Stabr/ize Soils 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 2015 D. R.STRONG ConsuRing Engineers Inc. Page 29 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16. 2015 i � 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: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP 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 7: Protect Drain Inlets BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action I 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 2015 D. R.STRONG Consulting Engineers Inc. Page 30 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 � Element 8: Stabilize Channels and Outlets BMP: Inspected Functioning Location Y N Y N NIP Probiem/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: Contro/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: Contro/Dewatenng BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP ��2015 D. R. STRONG Consulting Engineers Inc. Page 31 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Stormwater Discharges From the Site Observed? Problem/Corrective Action Y ON Location Turbidity i Discoloration ! Sheen Location Turbidity Discoloration i Sheen � Water Quality Monitoring Was any water quality monitoring conducted? ❑ Yes � No , If water quality monitoring was conducted, record results here: , if water quality monitoring indicated turbidity 250 NTU or greater; or transparency 6 cm or less, , was Ecology notified by phone within 24 hrs? ❑ Yes - No I If Ecology was notified, indicate the date, time, contact name and phone number below. !� Date: ' Time: I Contact Name: �I Phone#: � General Comments and Notes � Include BMP repairs, maintenance, or installations made as a result of the inspection. Were Photos Taken? ❑ Yes - No If photos taken, describe photos below: O 2015 D. R.STRONG Consulting Engineers Inc. Page 32 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16.2015 APPENDIX F - ENGINEERING CALCULATIONS � 2015 D. R STRONG Consultina Engineers Inc. Page 33 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 EXISTING SITE HYDROLOGY For the purpose of these calculations the predeveloped site conditions were modeled as "till forest". Modeling input Land cover Entire Site Till forest(ac) 4.08 Till Grass(ac) 0.00 ' Wetland (ac) 0.00 �" Impervious(ac) 0.00 � ; Scale Factor: 0.85 Time Step: Hourly Data Type: Reduced Project location: Landsburg Total Area: 4.08 Table 1 Pre-Developed KCRTS Modeling Input Modeling results Entire Site ' Flow Frequency Analysis Time Series File:predev.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0. 319 2 2/09/Ol 18: 00 0.378 1 100. 00 0.990 0. 052 7 1/05/02 16: 00 0.319 2 25. 00 0.960 0.203 4 2/28/03 16: 00 0.260 3 10.00 0.900 0. 036 8 3/03/04 2: 00 0.203 4 5.00 0.800 0. 186 5 1/05/05 10:00 0.186 5 3.00 0. 667 ', 0. 150 6 1/18/06 21:00 0.150 6 2.00 0.500 I� 0.260 3 11/24/06 5:00 0.052 7 1.30 0.231 0. 378 1 1/09/08 7:00 0.036 8 1. 10 0. 091 Computed Peaks 0.359 50.00 0 . 980 DEVELOPED SITE HYDROLOGY Soil type I The soil types are unchanged from pre-developed conditions. � Land covers KCRTS was used to model the developed peak runoff from the Site. The portions of the Site within the proposed clearing limits tributary to the proposed detention pond were � 2015 D R STRONG Consulting Engineers Inc Page 34 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 modeled as "Till Grass" and Impervious as appropriate. Results of the KCRTS analysis are included in this section. Modeling input Land cover Entire Site Till forest(ac) 0.00 Till Grass(ac) 1.71 Wetland (ac) 0.00 Impervious(ac) 2.30 Scale Factor: 0.85 Time Step: Hourly Data Type: Reduced , Project location: Landsburg Total Area: 4.01 Table 2 Developed KCRTS Modeling Input Modeling Results Entire Site Flow Frequency Analysis Time Series File:rdin.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0. 849 4 2/09/Ol 2:00 1. 55 1 100.00 0.990 0. 502 8 12/03/O1 17: 00 1. 03 2 25.00 0. 960 0.844 5 9/10/03 15: 00 0.982 3 10.00 0.900 0. 982 3 8/26/04 1:00 0.849 4 5.00 0.800 0. 808 7 10/28/04 18: 00 0.844 5 3.00 0 . 667 0. 838 6 10/22/05 17: 00 0.838 6 2.00 0 . 500 1.03 2 11/21/06 9:00 0.808 7 1.30 0.231 1.55 1 1/09/08 7:00 0.502 8 1.10 0.091 Comouted Peaks L 3� 50. 00 0 . 9E0 ��2015 D. R.STRONG Consulting Engineers Inc. Page 35 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 BYPASS AREA HYDROLOGY Modeling Input La nd cove r Enti re Site Till forest(ac) 0.00 Till Grass(ac) 0.05 Wetland (ac) 0.00 Impervious(ac) 0.02 Scale Factor: 0.85 Time Step: Hourly Data Type: Reduced Project location: Landsburg Total Area: 0.07 Table 3 Bypass KCRTS Modeling Input Modeling Results Bypass Flow Frequency Analysis Time Series File:bypass.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0. 012 3 2/09/Ol 2:00 0.024 1 100.00 0. 99C 0. 005 8 12/03/Ol 17: 00 0. 015 2 25.00 0. 96C 0. 009 7 9/10/03 15: 00 0.012 3 10.00 0. 9C0 0. 012 4 8/26/04 1:00 0.012 4 5. 00 0.800 0. 010 6 10/28/04 18:00 0.010 5 3. 00 0.667 ', 0. 010 5 10/22/05 17:00 0.010 6 2.00 0.500 ' 0. 015 2 11/21/06 9:00 0.009 7 1.30 0.231 0. 024 1 1/09/08 7:00 0.005 8 1. 10 0.091 Computed Peaks 0.021 50.00 0. 980 The on-site bypass areas satisfy all the requirements of Section 1.2.3.2.E of the Manual with a 100-year peak of 0.024 cfs. The runoff converges with the discharge of the facility almost immediately and will not create an adverse downstream impact. Facility design will provide compensatory storage such that the predeveloped discharge rates are not exceeded at the downstream point of compliance. 2015 D R. STRO"JG Consultina Enginee;s Inc. Page 36 of 44 Sto�nrr;a?er Pollu'ion Preventien Pian PJlae�t'ns Ranch �v".arch 16. 2015 FLOW CONTROL SYSTEM The Site will utilize a detention vault meeting the Level 2 Flow Control Criteria. The King County Runoff Time Series (KCRTS) software was used to size the detention facility. I Flow Control Facility Design Output �i Retention/Detention Facility ' Type of Facility: Detention Vault Facility Length: 74.50 ft ' Facility Width: 75.00 ft Facility Area: 5588. sq. ft Effecti`e Storage Depth: 9.00 ft Stage 0 Elevation: 445.00 ft ' Storage Volume: 50288. cu. ft Riser Head: 9.00 ft Riser Diameter: 18 .00 inches P2umber of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1.10 0.098 2 5.00 1.20 0.078 4.0 3 6.25 1.00 0.045 4 .0 Top Notch Weir: None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0. 00 445.00 0. 0.000 0.000 0.00 0. 01 445.01 56. 0.001 0. 004 0.00 0.02 445.02 112. 0.003 0. 005 0.00 0 .03 445.03 168. 0.004 0.006 0.00 0 . 05 445.05 279. 0.006 0. 007 0.00 0 . 06 445.06 335. 0.008 0. 008 0.00 0.07 445.07 391. 0.009 0. 009 0.00 0.08 445.08 447. 0.010 0. 009 0.00 0.09 445.09 503. 0.012 0. 010 0.00 0.27 445.27 1509. 0.035 0. 017 0.00 0. 44 445.44 2959. 0.056 0. 022 0.00 0. 62 445.62 3964. 0. 080 0. 026 0.00 0.80 445.80 4470. 0.103 0. 029 0.00 0. 97 445.97 5920. 0. 124 0. 032 0.00 1. 15 446.15 6926. 0. 148 0.035 0.00 1.33 446.33 7431. 0. 171 0.038 0.00 1.50 446.50 8381. 0.192 0. 040 0.00 1 . 68 446.68 9387 . 0.215 0. 043 0.00 1 . 86 446.86 10393. 0.239 0. 045 0.00 2 . 03 447.03 11343. 0.260 0. 047 0. 00 2 .21 447.21 12348. 0.283 0. 049 0.00 2.39 497.39 13354 . 0.307 0.051 0.00 �2015 D. R.STRONG Consulting Engineers Inc. Page 37 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 2.56 447.56 14304 . 0.328 0. 053 0.00 2.74 947.79 15310. 0.351 0. 054 0.00 2. 92 947. 92 16316. 0.375 0. 056 O.00i 3.09 948.09 17265. 0.396 0.058 O.00 3.27 948.27 18271. 0.419 0.059 O.00 3.44 448.44 19221. 0.441 0. 061 O.OG 3. 62 448. 62 20227 . 0. 464 0. 062 0.00 3.80 448.80 21233. 0.487 0. 064 0.00 3.97 448.97 22182. 0.509 0.065 0.00 4. 15 449.15 23188. 0.532 0.067 O.OG 4.33 449.33 24199 . 0.555 0. 068 0.00 4.50 449.50 25144. 0.577 0. 070 0.00 4.68 449.68 26150. 0. 600 0.071 0.00 4.86 449.86 27155. 0. 623 0.072 0.00 5.00 450.00 27938. 0. 641 0. 073 0.00 5.01 450.01 27993. 0. 643 0. 074 O.00 5.02 450.02 28049. 0. 644 0. 075 0.00 5.04 450.04 28161. 0. 646 0. 076 0.00 5.05 450.05 28217. 0. 648 0. 078 0.00 5. 06 450.06 28273. 0. 649 0.081 0.00 5.07 450.07 28329. 0.650 0.085 0.00 5.09 450.09 28440. 0.653 0.086 0.00 5. 10 450.10 28496. 0. 654 0.086 0.00 5.11 450.11 28552. 0. 655 0. 087 0.00 5.29 450.29 29558. 0.679 0. 096 0.00 5.47 450.47 30564. 0.702 0. 103 0.00 5. 64 450.64 31514. 0.723 0. 109 0. 00 5.82 450.82 32519. 0.747 0. 114 0. 00 5. 99 450. 99 33469. 0.768 0. 119 0.00 6.17 451. 17 34475. 0.791 0. 124 0.00 6.25 451.25 34922. 0.802 0. 126 0.00 6.26 451.26 34978. 0.803 0. 126 0.00 6.27 951.27 35034. 0.804 0. 127 O.00 6.28 951.28 35090. 0.806 0. 128 0.00 6.29 451.29 35145. 0.807 0. 130 0.00 6.30 451.30 35201. 0.808 0. 132 0.00 6.31 451.31 35257 . 0.809 0. 134 0.00 6.32 451.32 35313. 0.811 0. 135 0.00 6.33 451.33 35369. 0.812 0. 135 O.OG 6.34 451.34 35425. 0.813 0. 136 0.00 6. 52 451.52 36431. 0.836 0. 146 0.00 6.70 451.70 37436. 0.859 0. 154 0.00 6.87 451.87 38386. 0.881 0. 161 0.00 7.05 452.05 39392. 0. 904 0. 167 O.00 7.23 452.23 40398. 0. 927 0. 173 0.00 7.40 452.40 41348. 0. 949 0. 179 0.00 7.58 452.58 92353. 0. 972 0. 184 0.00 7.76 452.76 43359. 0. 995 0. 189 0.00 7. 93 452.93 44309. 1.017 0. 194 0.00 8.11 453.11 45315. 1.040 0. 199 0.00 8.28 453.28 46265. 1.062 0.204 O.OU 8.46 453.46 47270. 1.085 0. 208 0.00 8. 64 453.64 48276. 1.108 0. 213 O.00 8.81 453.81 49226. 1.130 0.217 0.00 C 2015 D. R.STRONG Consulting Engineers Inc. Page 38 of 44 Storm�vater Pollution Prevention Plan Maertins Ranch March 16, 2015 8. 99 453.99 50232. 1. 153 0.221 0.00 9.00 454.00 50288. 1. 154 0.222 0.00 9. 10 454.10 50846. 1. 167 0. 686 0.00 9.20 454.20 51405. 1. 180 1. 530 0.00 9.30 454.30 51964. 1. 193 2. 630 0.00 9.40 454.40 52522. 1.206 3. 930 0.00 9.50 454.50 53081. 1.219 5. 400 0.00 9. 60 454. 60 53640. 1.231 6. 830 0.00 9.70 454.70 54199. 1.244 7.360 0.00 9.80 454.80 54758. 1.257 7. 850 0.00 9. 90 454. 90 55316. 1.270 8.310 0.00 10.00 455.00 55575. 1.283 8.750 0.00 10. 10 455.10 56434. 1.296 9. 170 0.00 10.20 455.20 56993. 1.308 9. 570 0.00 10.30 455.30 57551. 1.321 9. 950 0.00 10.40 455.40 58110. 1.334 10. 320 0.00 10.50 455.50 58669. 1.347 10. 680 0.00 10. 60 455.60 59228 . 1.360 11. 020 0.00 10.70 455.70 59786. 1.373 11.350 0.00 Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 1.55 1. 45 9.19 454 . 19 51350. 1 . 179 , 2 1. 03 0.31 9.02 454 .02 50398 . 1 . 157 3 0. 85 0.22 8.94 453. 94 49930. 1 .146 4 0. 51 0. 14 6.41 451.41 35827 . 0 .822 ' 5 0. 58 0. 12 6.20 451.20 34646. 0.795 6 0. 84 0. 07 4.85 449.85 27081. 0 . 622 I� 7 0. 98 0. 06 3.33 448 .33 18609. 0 .427 8 0. 45 0. 05 2.36 447 .36 13202 . 0 . 303 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Calc ' 1 1.45 0.02 ******** ******* 1. 47 2 0.31 0.01 ******** 0.32 0.32 3 0.22 0.01 ******** ******* 0. 22 ' 4 0. 14 0.01 ******** ******* 0. 14 �� 5 0. 12 0.01 ******** ******* 0. 13 �� 6 0.07 0.01 ******** ******* 0. 07 I 7 0.06 0.01 ******** ******* 0. 06 8 0.05 0.01 ******** ******* 0. 05 ---------------------------------- Route Time Series through Facility Inflow Time Series File:rdin.tsf Outflow Time Series File:rdout.tsf POC Time Series File:dsout jInflow/Outflow Analys_s Peak Inflow Discharge: 1 .55 CFS at 7 : 00 on Jan 9 in Year 8 Peak Outflow Discharge: 1.45 CFS at 8 : 00 on Jan 9 in Year 8 Peak Reservoir Stage: 9.19 Ft Peak Reservoir Elev: 454 .19 Ft Peak Reservoir Storage: 51350. Cu-Ft O 2015 D. R.STRONG Consufting Engineers Inc. Page 39 of 44 5tormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 . 1. 179 AC-Ft Add Time Series:bypass.tsf Peak Summed Discharge: 1. 46 CFS at 8: 00 on Jan 9 in Year 8 Point of Compliance File:dsout.tsf Flow Frequency Analysis Time Series File:rdout.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0.220 3 2/09/Ol 21:00 1.45 9. 19 1 100.00 0. 990 0. 051 8 11/05/Ol 3:00 0 . 313 9.02 2 25.00 0.960 0. 125 5 3/Ol/03 8:00 0 .220 8 . 95 3 10.00 0.900 0. 060 7 8/26/04 7:00 0 .140 6.41 4 5.00 0.800 0. 140 4 1/08/05 6:00 0.125 6.21 5 3.00 0. 667 0. 072 6 10/28/05 3:00 0.072 4 .85 6 2.00 0.500 0. 313 2 11/24/06 8:00 0.060 3.33 7 1.30 0.231 1. 45 1 1/09/08 8:00 0.051 2 .36 8 1. 10 0.091 Computed Peaks 1.07 9. 15 50. 00 0. 980 Flow Frequency Analysis Time Series File:dsout.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.225 3 2/09/O1 20:00 1. 46 1 100.00 0. 990 0. 052 8 11/05/O1 2:00 0.317 2 25.00 0. 960 0. 127 5 3/Ol/03 7:00 0.225 3 10.00 0. 900 0. 061 7 8/26/04 5:00 0. 142 4 5.00 0.800 0. 142 4 1/08/05 6:00 0. 127 5 3.00 0. 667 0. 074 6 10/28/05 0:00 0.074 6 2 .00 0.500 0. 317 2 11/24/06 8:00 0.061 7 1.30 0.231 1.46 1 1/09/08 8:00 0.052 8 1.10 0.091 Computed Peaks 1. 08 50.00 0.980 � Flow Duration from Time Series File: rdout.tsf Cutoff Count Frequency CDF Exceedence_Probability ! CFS o 0 o I 0.004 27656 45.101 45. 101 54.899 0.549E+00 0.013 8206 13.382 58.483 41.517 0.915E+00 0. 022 7711 12.575 71.058 28. 942 0.289E+00 0. 031 7206 11.751 82.810 17. 190 0.172E+00 0. 040 4427 7.220 90.029 9.971 0. 997E-01 'I 0. 048 2589 4.214 94.243 5.757 0.576E-01 �i 0. 057 1400 2 .283 96.526 3.474 0.347E-01 0. 066 1075 1 .753 98.280 1.720 0.172E-01 0. 075 574 0. 936 99.216 0.784 0.784E-02 0. 084 18 0.029 99.245 0.755 0.755E-02 0. 092 57 0.093 99.338 0. 662 0. 662E-02 0. 101 66 0.108 99.446 0.554 0.554E-02 0. 110 71 0.116 99.561 0.439 0. 439E-02 O 2015 D. R.STRONG Consufting Engineers Inc. Page 40 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16, 2015 � 0. 119 99 0.161 99.723 0.277 0.277E-02 0. 127 37 0.060 99.783 0.217 0.217E-02 0. 136 5 0.008 99.791 0.209 0.209E-02 0. 145 16 0.026 99.817 0. 183 0. 183E-02 0. 154 8 0.013 99.830 0. 170 0. 170E-02 0. 163 9 0.015 99.845 0.155 0.155E-02 0. 171 10 0.016 99.861 0.139 0.139E-02 0. 180 11 0.018 99.879 0.121 0. 121E-02 0. 189 12 0.020 99.899 0.101 O. 101E-02 0. 198 15 0.024 99. 923 0.077 0.766E-03 0.207 18 0.029 99. 953 0.047 0.473E-03 0.215 14 0.023 99. 976 0.024 0.245E-03 0.229 13 0.021 99. 997 0.003 0.326E-04 0.233 0 0.000 99. 997 0.003 0.326E-04 0.242 0 0. 000 99. 997 0.003 0.326E-04 0.250 0 0.000 99. 997 0.003 0.326E-04 0.259 0 0.000 99. 997 0.003 0.326E-04 0.268 0 0.000 99. 997 0.003 0.326E-04 0.277 0 0.000 99. 997 0.003 0.326E-04 0.286 0 0.000 99. 997 0.003 0.326E-04 0.294 1 0.002 99.998 0.002 0. 163E-04 0. 303 0 0.000 99. 998 0.002 0. 163E-04 0. 312 0 0.000 99. 998 0.002 0. 163E-04 Flow Duration from Time Series File:dsout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS ° ° ° - a o 0 0.005 27680 45.140 45. 140 54.860 0.549E+00 0. 013 8302 13.539 58. 679 41. 321 0.413E+00 0. 022 7639 12 .458 71. 137 28 . 863 0.289E+00 0. 031 7204 11.748 82.885 17 .115 0. 171E+00 0. 040 4349 7 .092 89. 977 10.023 O. 100E+00 i 0. 049 2617 4 .268 94.245 5.755 0. 576E-01 0. 058 1388 2.264 96.508 3.492 0.349E-01 0. 067 1069 1.743 98.252 1.748 0. 175E-01 0. 076 584 0. 952 99.204 0.796 0.796E-02 0. 085 24 0.039 99.293 0.757 0.757E-02 0. 094 52 0.085 99.328 0. 672 0. 672E-02 0. 103 68 0.111 99.439 0.561 0.561E-02 0.111 74 0. 121 99.560 0.440 0. 440E-02 0. 120 94 0. 153 99.713 0.287 0.287E-02 0. 129 42 0.068 99.781 0.219 0.219E-02 0. 138 7 0.011 99.793 0.207 0.207E-02 0. 147 15 0.024 99.817 0.183 0. 183E-02 0. 156 8 0.013 99.830 0.170 0. 170E-02 0. 165 7 0.011 99.842 0. 158 0. 158E-02 0. 174 11 0.018 99.860 0. 140 0. 140E-02 0. 183 11 0.018 99.878 0.122 0. 122E-02 0. 192 11 0.018 99.896 0.104 0. 109E-02 0.201 15 0.024 99. 920 0.080 0.799E-03 0.209 19 0.031 99. 951 0.049 0.989E-03 0.218 13 0.021 99.972 0.028 0.277E-03 0.227 15 0.024 99.997 0.003 0.326E-04 0.236 0 0.000 99. 997 0.003 0.326E-04 ' O 2015 D. R.STRONG Consulting Engineers Inc. Page 41 of 44 Stormwater Pollution Prevention Plan MaeRins Ranch March 16,2015 0.245 0 0.000 99. 997 0.003 0.326E-04 0.254 0 0.000 99. 997 0.003 0.326E-04 0.263 0 0.000 99. 997 0.003 0.326E-04 0.272 0 0.000 99.997 0.003 0.326E-04 0.281 0 0.000 99.997 0.003 0.326E-04 0.290 0 0.000 99.997 0.003 0.326E-04 0.299 1 0.002 99.998 0.002 0. 163E-04 0. 307 0 0.000 99. 998 0.002 0. 163E-04 0. 316 0 0.000 99. 998 0.002 0. 163E-04 Duration Comparison Anaylsis Base File: predev.tsf New File: dsout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New %Change Probability Base New %Change 0. 075 I O.10E-01 0.82E-02 -20.4 � O. 10E-01 0.075 0.073 -2. 6 0. 093 � 0.70E-02 0.68E-02 -2.8 � 0.70E-02 0.093 0.092 -1. 9 0. 112 � 0.48E-02 0.43E-02 -8. 9 � 0. 48E-02 0. 112 0.109 -2 . 6 0. 131 � 0.31E-02 0.22E-02 -30. 9 I 0.31E-02 0.131 0.119 -8 . 9 0. 150 I 0.20E-02 0. 18E-02 -12 .1 � 0.20E-02 0. 150 0.140 -6.3 0. 169 I 0.15E-02 0. 15E-02 -1.1 � 0. 15E-02 0. 169 0. 168 -0. 3 0. 187 � O.10E-02 0.11E-02 9.5 I O. 10E-02 0. 187 0. 192 2 . 5 0.206 I 0.78E-03 0.62E-03 -20.8 I 0. 78E-03 0.206 0.201 -2 . 6 0.225 I 0.57E-03 0.49E-04 -91.4 � 0.57E-03 0.225 0.207 -8 .2 0.244 I 0.33E-03 0.33E-04 -90.0 I 0.33E-03 0.244 0.216 -11 . 6 0.263 I 0.20E-03 0.33E-04 -83.3 I 0.20E-03 0.263 0.221 -15 .7 0.281 � 0.15E-03 0.33E-04 -77.8 I 0. 15E-03 0.281 0.223 -20. 9 0. 300 � 0. 98E-04 0. 16E-04 -83.3 I 0. 98E-04 0.300 0.224 -25.4 0. 319 � 0. 16E-04 O.00E+00 -100.0 I 0. 16E-04 0.319 0.317 -0. 6 Maximum positive excursion = 0.005 cfs ( 3.Os) '�, occurring at 0.177 cfs on the Base Data:predev.tsf '� and at 0. 183 cfs on the New Data:dsout.tsf � Maximum negative excursion = 0.083 cfs (-26. 9o� occurring at 0. 308 cfs on the Base Data:predev.tsf � and at 0.225 cfs on the New Data:dsout.tsf ' C�2015 D. R. STRONG Consulting Engineers inc. Page 42 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 J � PEAK PLOT '�nd„�-n�..r,�,�.,�,-Aca-� .. .-. .; � ''��. Retum Period �.. 2 5 70 20 50 100 �� 10� � rdout.Dks Fn Landsburg _ • dsout Pke I e. pr=dcr.pk5 I ♦ , �Do N U „ m o _ � m R o � � 0 ° I a � �.... 000 � '.. '� �Q� � � ♦ i ♦ � �� 1 2 5 70 20 30 d0 50 60 70 80 90 95 98 99 Cumuleti�e ProbebiNty DURATION ANALYSIS �CauvN-D�ratia�bwlysa-KIXZ ,o C II ' a 0 rdo�t dur o dsoutdur • tergEt.dur o �` --F`_ eo \ �.*� ' �. c 4 �� '4� F \\�` � \ ��V R �� . N � � � o fIII u �.. I� �`'\. � � ��`, y�� 1 � o � u I' 00 I � � �� O � � i . 10� 10� 10�3 10�� 10 � 10°I� � ProOzbiliry Exceedence '� : 2015 D. R.STRONG Consulting Engineers Inc. Page 43 of 44 Stormwater Pollution Prevention Plan Maertins Ranch March 16,2015 SEDIMENT POND SIZING The pond was sized using the requirements stated in appendix "D" of the 2009 I KCSWDM Section D.4.5.2 which requires 2080 s.f. of surface area per cfs of inflow 'I which was calculated using KCRTS (15 min. time steps) to analyze the developed site � conditions. !, DEVELOPED 15-MINUTE TIME SERIES , Modeling input ' Error! Objects cannot be created from editing field ' codes. Modeling results Developed 15-Min Flow Frequency Analysis T_me Series File:dev-15min.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- F1ow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 1. 10 6 8/27/Ol 18:00 3.58 1 100.00 0. 990 0.798 8 1/05/02 15:00 2.45 2 25 .00 0. 960 2. 45 2 12/08/02 17:15 1.54 3 10.00 0. 900 0. 882 7 8/23/04 14:30 1.47 4 5.00 0. 800 1. 47 4 11/17/04 5:00 1.34 5 3.00 0. 667 1. 34 5 10/27/05 10:45 1. 10 6 2 .00 0. 500 ' 1. 54 3 10/25/06 22:45 0. 882 7 1.30 0.231 3. 58 1 1/09/08 6:30 0. 798 8 1. 10 0. 091 Comnuted Peaks 3.20 50. 00 0. 980 Catchment Area: 4.01 ac. 2-year peak flow rate......................................1.10 cfs Required Surface Area...................................2,288 s.f. Provided surface Area....................................2,340 s.f. :,2015 D. R. STRONG Consulting Engineers Inc. Page 44 of 44 Stormwater Pollution Pre�ention Plan Maertins Ranch March 16,2015 I I APPENDIX "E" DECLARATION OF COVENANT 2015 D. R STRONG Cons�i!ting Engineers Inc P.4aertins Ranch Page 54 Technical Inform�tion Repo��t City of Renton i u�� o�� ' RECORDING REQUESTED BY AND '' WHEN RECORDED MAIL TO: CITY CLERK'S OFFICE CITY OF RENTON 1055 SOUTH GRADY WAY � REI�TTON, WA 98057 DECLARATION OF COVENANT FOR MAINTENANCE AND INSPECTION OF FLOW CONTROL BMPS Grantor: PNW Holdings, LLC Grantee: City of Renton Legal Description: AttaChed Additional Legal(s)on: Assessor's Tax Parcel ID#: 032305-9021 IN CONSIDERATION of the approved City of Renton{check one of the following) ❑ residential building permit, ❑ commercial building permit, ❑ clearing and grading permit, � subdivision permit, or ❑ short subdivision permit for Application File No.LUA/SWP14-001568 relating to the real property("Property") described above,the Grantor(s),the owner(s) in fee of that Property,hereby covenants(covenant)��ith City or Renton, a political subdivision of the sfate of�'Vashitlgton, that he/she(they)will observe, consent to, and abide by the conditions and obligations set forth and described in Paragraphs 1 through 8 below with regard to the Property. Grantor(s)hereby grants(graiit), covenants(covenant),and agrees{agree)as follows: l. Grantor(s) or his/her(their)successors in interest and assigns("Owners")shall retain,uphold, and protect the stonnwater management devices, features,pathways, limits, and rest�•ictions,lcnown as flow control best management practices("BMPs"), shown on the approved Flo��Control BMP Site Plan for the Property attached hereto and incorporated herein as EaLhibit A. 2. The O�vners shall at their o«�n cost, operate,maintain,and keep in good repair,the Property's BMPs as described in the approved Design and Maintenance Details for each BMP attached hereto and incorporated herein as E�chibit B. 3. City or Renton shall provide at least 30 days written notice to the O��ners that eFitry on the Property is planned for the inspection of the BMPs. After the 30 days, the Owners shall allo«�the City of Renton to enter for the sole purpose of inspecting the BNIPs. In lieu of inspection by the City,the O«�ners may elect to engage a licensed civil eugineer registered in the state of Washington«�ho has eYpertise ul drainage to inspect the BMPs and provide a written report describing their condition. If the engineer option is chosen,the Owners shall provide written notice to the City of Renton��ithin fifteen days of receiving the City's notice of inspection. Within 30 days of giving this notice,the Owners, or the engineer on behalf of the Owners,shall provide the engineer's report to the City of Renton. If the report is not provided in a timely manner as specified abot�e,the City of Renton may inspect the BMPs without fi►rther notice. 4. If the City determines from its inspection, or fi•om an engineer's report provided in accordance `vith Paragraph 3,that maintenance,repair,restoration, and/or mitigation work is required for the BMPs, The City shall notify the Owners of the specific maintenance,repair,restoration, and/or mitigation ti�vork (Work)required under RMC 4-6-030. The City shall also set a reasonable deadline for completing the Work or provic�ing an engineer's report that verifies completion of the�'�'ark. After the deadline has passed,the O�i�ners shall allow the City access to re-inspect the BMPs unless an enginee�•'s report has been provided verifying completion of the Work. If the work is not completed properly within the tiine frame set by the City,the City may initiate an enforcement action. Failure to properly maintain the BMPs is a violation of RMC 4-6-030 and may subject the Owners to enforcement under the RMC 1-3, including fines and penalties. 5. Apart fi�om performing routine landscape maintenauce,the Owners are hereby required to obtain��ritten approval fi�om tlie City oi•Renfon before perfot-inin�any alterations or modifications to the. BMPs. 6. Any notice or approval required to be given by one party to the other Under the provisions of this Declaration of Covenant shall be effective upon personal delivery to the other party, or after three(3) days from the date that the notice or approval is mailed with delivery confirmation to the cun�ent address on record with each Party. The parties shall notify each other of any change to their addresses. 7. This Declaration of Covenant is intended to promote the efficient and effective manageinent of surface water drainage on the Properiy,and it shall inure to the benefit of all the citizens of the City of Renton and its successors and assigns. This Declaration of Covenant shall run�vith the land and be bindulg upon Grantor(s), and Grantor's(s') successors in interest and assigns. 8. This Declaration of Covenant may be terminated by execution of a written agreement by the Owners and the City of Renton that is recorded by King County in its real property records. IN WITNESS V��REOF,this Declaration of Covenant for the Maintenance and Inspection of Flow Control BMPs is executed this day of , 20 GRANTOR, owner of the Propeity GRANTOR, owner of the Property � STATE OF WASHINGTON ) COUNTY OF KING )ss. , On this day personally appeared before me: I' ,to me known to be the individual(s) described in and who executed the within and foregoing instrument and acknowledged that they signed�the saine as their free and voluntary act and deed, for the uses and purposes therein stated. Given under my hand and official seal this day of ,20 Printed name Notary Public in and for the State of Washinb on, residing at My appointment expires LEGAL DESCRIPTtON PARCEL A: THE NORTH 677.44 FEET OF THE WEST 1/2 OF THE WEST 1/2 OF THE SOUTHEAST 1/4 OF THE SOUTHEAST 1/4 OF SECTlON 3, TOWNSHIP 23 NORTH RANGE 5 EAST., W.M., IN KING COUNTY, WASHINGTON; EXCEPT THE WEST 130 FEET OF PORTION LYING SOUTH OF A LINE 339.5 FEET SOUTH OF THE NORTH LINE; EXCEPT THAT PORTION OF SAID NORTH 677.44 FEET LYING SOUTH OF THE FOLLOWING DESCRIBED LINE: BEGINNING AT THE INTERSECTION OF THE SOUTH LINE OF THE NORTH 677.44 FEET WITH THE EAST LINE OF THE WEST 1/2 OF THE WEST 1/2 OF THE SOUTHEAST 1/4 OF THE SOUTHEAST 1/4 OF SAID SECTION 3; THENCE NORTH 87 DEGREES, 49 MINUTES AND 08 SECONDS WEST ALONG SAID SOUTH LINE A DISTANCE OF 89.01 FEET TO THE BEGINNING OF SAID LINE; THENCE NORTH 67 DEGREES, 07 MINUTES, 57 SECONDS WEST A DISTANCE OF 119.88 FEET TO INTERSECTION OF THE EAST LINE OF THE WEST 130 FEET OF THE SOUTHEAST 1/4 OF THE SOUTHEAST 1/4 OF SAID SECTION 3, SAID INTERSECTION BEING TERMINUS OF LINE; EXCEPT PORTION, IF ANY, CONVEYED TO JAMES L. DIXON, ET UX, BY DEEDS RECORDED UNDER ' RECORDERS NOS. 6468344 AND 7207120398. � PARCEL B: A NON-EXCLUSIVE EASEMENT FOR INGRESS AND EGRESS AS CREATED BY INSTRUMENT RECORDED AS RECORDING NUMBER 7609140487. TAX PARCEL NUMBER: 0323059021 Q1 � I I � � I � � � � ��'� � �' I ( I j � BASIC DlSPERS/ON 4/lA SPLASH i , ( � ; BLOCKS FO,R LOTS 11-13 TO BE ' ` �T P) ._--�. . , I `�- ---- - � � '' - � . _ . ' � _ - - , U ED FOR FLOW CONTRO BMP ' ` � ' - NE�6Tf/sT ; _ _� - , -: - , a _ ----- .zo __�_._ � ar _ r sZ i � -- -- _i iA/!�/l,Ullll�/nin /lll�7l/O/l9//IA, � � - - � - , � -- �' � .- -- -�s. __ _ - _ . ... .._. _�.—... . � , , ��.,r _ �_� :::�- _: —'_ — �,3 ...:... � - �-a ------ , - -- — � � .� _:f —.. � __� _ . r 25 _ : �....`. i � � I � � �----- `r' ' � , ' � �' �-� �-- ----, �� ' ' � �3 ' � �' � � � �:�`: ( ; a � , � ; � ;�� ; � � ' f1.. �_--_-_� .:'. -. L -___-_J I \J , ; �. ; . �______� ::.�::. r _____-� f. � O (_-._. I � .. ... I I I I__ ____ ___._ __..__ __ , , � � � ,A►, ! � �' � 2 ; :;��::: I 12 ; � m, , , , , ' .. , , � , � � � ' ZI ' i � - t� ' ------' ' L____-_J ."..... L J ,, m . , :,::. - . --___� H :.�:�:.:� Y"� r__--_-_� N �, � _ ..� - - I I I I I , ...... � i _ ' -- ---- � . � '�_ :' t I I :::..;;: � I � - -.._ ._-- � i� I 3 ' ' � ' � �1 ' ETENTION VAULT ' �BASIC DISPERSION U! ; � � i � i � .. .. i � .. ... � , i � i � ;:: : . � � i SPLASH BLOCKS FOR EACH � ______, ' L______J RESIDENCE TO BE USED 'FOR --------, 4 �— — — — _ — FLb,W CONTROL BMP (TYP.) ; � � i , �� i �i } �� i I . �. , . � 4 , � 90 � ---. � � ; �'�...�. \ � - .�:7. � �I _�. `V I _.- - --- ---� � � -- � ..,��\ 1 � �.'.:Y::. �------ -----� - _.� ...... -----J ,. ` ��, s � � � ... ... ------� -.\ �\ ;.t� ------ ... ... r----- L__— � � I ti l, , I 3 f �,, r � ,�.;I i j g � � , . , ' 2� ;;J ' + : i � , � . �: ,,.,J .....:: j I i\\'v ^ ,../ I .'.Y::�. � �---------- �� ;' i.`Y .y:, ... �x-::: ....... / _•-_� ... . � r----------� . .. / f� ` I � :�:.:�~; j i ^ i --� --- -— --- --�- � I � %, J ' �y i C3 i i `\ " '" I i �------- � 1 ��" ' � -__ ; �� , � ;:� r------ � .� � � ;::i:: � � i � f 7 i �� , � -- -�— - - - -- -- , � �. � `�� :: .� l i I . . � . . � . � � � � � . � � ,::. ,, �-------� � m, -:. :. : � . - - --- � � �:. r�------, : � `'. Z��. � I ;::�:: :.;:::;:. � �\ � '�. O' � ;:::::::�:;:::; :;;: � ' ; Z` I ,........ i i i ; I � .... _ � �6 � � � .... .... , : ...... ... ... :. ...:.: . � ...... ... ... . ...... .. .. . ..... ... ... . , , . _..... . �, __ _� �.::::: `� :::;: � i � - - � � cS� ., I _ ___ _ ......::.:. ___ � � � rl':::::.:'.I.....:.' -_� � �QG ' .- I — — �:.:. ��-----� , � I � � `. ' ..-' :�i..- -:. ... , I � . . . - � � . ... ___�`_ — - -- - - - , � � i \ _, I ,. , I — — : — _ ::_ � , � , : 1 `t �4 I I S.h`�j i I � _______JI I I . �� J_� f Tv--- I`�, ! ; I I � �'�. � ,. I , I �; � � � I EXH/B/T A N O RT H GRAPHIC SCALE 0 50 100 150 `�� `� 1 INCH = 100 FT. � EXHIBIT B � O TElST OF WS�F2llC1iONS FUR BA�SIC E31Sf"ERSION � Yaurproperty contai�s a stom»v�ferman�gert3enf�faw confrol BMP(UesE management praetice}ca[fed "��vi�disper ion,"tiahich was insfaf�sd ta mitrgate Ifie sfarmwaterquan�and qua[ity impacts ot same or � ali�f the amper�iou�surFaces or non-natiue penRous surF�c�s an yat�r pEc�perfy. Basie disperseon 9s a j strategy�far ufilizing any avaifable capa city of onsite�egstat�d are�s to rafain,absorb,and filter fhe nEnof� iram de•defope��urfaces. This flavr control BMP has f+r.�a prriannaoy c4mponents that must he msintained:(9) the devices that dispVrse runaffifrom ihe developed auRaces and(2)the�egetafed area avzr tvhich r�naff I €s d€�persed_ II Dispersion Devices I The di�peryian device�used on your propert}•Encl�ude the fo[loviing as ondicate�an fhe ffow corrErol6MP I s�e plan.O splavh ktlock�,a To��a3as,E7 grave]fifled frenches,p sheet fiow. '�he size,placement, can�sposition,arad davrnstraam ftowpafh�ofthee.e device�as depicted by the flovr contro9 Bh7P site plan and I design d�fail�r�ust tse maintained and may not l�e changed v�ithouf w�itfen ap.proval either from#he King �ounty Wafer and Land Resources Division or ifirough a fuiure dev�lopment pertnif from Kir�g County. Dispersion de�dlces musE 6E tR�pecfed anne�.aliy and after majar stom�events to identify and repair any physical defects. VJhen na6ve soil is expasEd or eeosion chann�ls t�re presen�,the sources of the ero�ion ar��oncentrafed ff��1r n�ed fn l�e identified and mitigafed. Concenirafed ftovr can be m�tigated hy leve{ing Qhe edge of the�erviou�area andlor�aligRing or�plenishing the rocks in fhe dispersion device,suc[�as en rock pads and grati�el fi[led�trenches_ . Vegetsted Flowpati�s Tha vegefated area overvthich runoff is dispersed niust Ue mainfained in gaad condi&on free of 6are spots and obsfrucfons that urould concen4ratQ Rows_ FIGUPE C:3.4.4 TYPIC:�#L SFL.�HBLflC'�i F4R BA.SIC-DL�PERSIOiti' house I -- roof � da�m�.pout serves up tD 7OD S.E. q;roof r�p•�_ l. vegea�ed fla�v p34h splash hlock �- �- -' �� ' �dotivnspcatextension NTS /�sFfash / 6fack ��i� Return Address: City Clerk's Office City of Renton � 1055 S Grady Way Renton,WA 98057 DECLARATION OF COVENANT FOR INSPECTION AND � MAINTENANCE OF STORMWATER FACILITIES AND BMPS Grantor: PNW Holdings, LLC I Grantee: City of Renton Legal Description: AttaChed Assessor's Tvc Parcel ID#: 032305-9021 IN CONSIDERATION of the approved City of Renton SUbdlvlslon permit for application file No.LUA/SWP 14-001568 relating to the real property("Property") described above,the Grantor(s),the owner(s) in fee of that Property,hereby covenants(covenant)with the City of Renton,a political subdivision of the state of Washington,that he/she(they)will observe,consent to, and abide by the conditions and obligations set forth and described in Paragraphs 1 through 10 below with regard to the Property, and hereby grants(grant)an easement as described in Paragaphs 2 and 3. Grantor(s)hereby grants(grant),covenants(covenant),and agrees(agree)as follows: 1. The Grantor(s) or his/her(theu•)successors in interest and assigns ("Owners of the described property")shall at their owrn cost,operate,maintain,and keep in good repair,the Property's stormwater facilities and/or best management practices("BMPs") constructed as required in the approved � construction plans and specifications on file with the City of Renton and submitted to the City of Renton for the review and approval of permit(s) LUA14-001568 .The property's stormwater facilities and/or best management practices ("BMPs"}are shown and/or listed on Exhibit A.The property's stormwater facilities and/or BMPs shall be maintained in compliance with the operation and maintenance schedule included and attached herein as Exhibit B. Stormwater facilities include pipes, swales,tanks,vaults,ponds,and other engineered structures designed to manage and/or treat stormwater on the Property. Stormwater BMPs include dispersion and infiltration devices,native vegetated areas,permeable pavements,vegetated roofs, rainwater harvesting systems,reduced impervious surface coverage,and other measures designed to reduce the amount of stormwater runoff on the Property. 2. City of Renton shall have the right to ingress and egress over those portions of the Property necessary to perform inspections of the stormwater facilities and BMPs and conduct maintenance activities specified in this Declaration of Covenant and in accordance with RMC 4-6-030. 3. If City of Renton determines that maintenance or repair work is reyuired to be done to any of the stormwater facilities or BMPs,City of Renton shall give notice of the specific maintenance and/or repair work required pursuant to RMC 4-6-030. The City shall also set a reasonablc time in which such ( Page 1 of 3 Form Approved by City Attomey 10/2013 «�ork is to be completed by the O�vners. If the above required maintenance or repair is not complet�.l within the time set by the City,the City may perform the requiced maintenance or repair,and hereb� i; given access to the Property,subject to the exclusion in Paragraph 2 above, for such purposes. Writtcn notice will be sent to the Owners stating the City's intention to perform such work. This work will not commence until at least seven(7)days after such notice is mailed. If, within the sole discretion of thc City,there exists an imminent or present danger,the seven (7) dav notice period �vill be�vaived and maintenance and/or repair work�vill begin immediately. 4. If at any time the City of Renton reasonably dctcrinines that �storil��ate�� 1�acilit}� or 131�1 P oi� the Property creates any ofthe hazardous conditions listed in R'vIC 4-4-060 Ci or relevant municipal successor's codes as applicable and herein incorporated by reference,the City may take measw�es specified therein. 5. The Owners shall assume all responsibility for the cost of any maintenance or repair�i orl: completed by the City as described in Paragraph 3 or any measures taken by the City to address ha-r_ardous conditions as described in Paragraph 4. Such responsibility shall include reimbursement to the City within thirty(30) days of the receipt of the invoice for any such work performed. Overdue payments ��i l l require payment of interest at the cui•rent legal rate as liquidated damages. If legal action ensues,t}ie prevailing party is entitled to recover reasonable litigation costs and attorney's fees. 6, The Owners are hereby required to obtain written approval from City of Renton prior to filling, piping, cutting, or removing vegetation(except in routine landscape maintenance)in open vegetated stormwater facilities(such as swales,channels,ditches,ponds, etc.), or performing anti alterations ar modifications to the storm�vater facilities and BI��1Ps referenced in this Declaratio�l of i Covenant. � 7. Any°notice or consent required to be gi�-en or other�-vise provided for by the provisions of this Agreement shall be effective upon personal delivery, or three(3) days after mailing by Certified Mail, retttrn receipt requested. 8. With regard to the matters addressed herein,this agreement constitutes the entire agreement between the parties, and supersedes all prior discussions,negotiations,and all agreements whatsoever whether oral or written. � 9. This Declaration of Covenant is intended to protect the value and desirability of the real property described above, and shall inure to the benefit of all the citizens of the City of Renton a�id its successors and assigns. This Declaration of Covenant shall run«�ith the land and be bindin�upon Grantor(s),and Grantor's(s') successors in interest,and assigns. 10. This Declaration of Covenant may be terminated b} execution of a��ritten a��eetnent by the Owners and the City that is recorded by King County in its real property records. IN WITNESS WHEREOF,this Declaration of Covenant for the Inspection and Nlaintenance of Storilni-ater Facilities and BA�Ps is e�ecuted this day of , 20___ GRAN'TOR, o��ner of the Propert� GIZANI�OIZ, o��ler of tlle f'r��ert}• Y�ec 2 of 3 I�orul:lppro�°c�bti�Cit}'Attornc�� 10,�?O1� STATF OF WASHINGTON ) COUNTY OF KING )ss. On this day personally appeared before me: ,to me l:no«�n to be the individual(s) described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their fi•ee and voluntary act and deed,for the uses and purposes therein stated. Given under my hand and official seal this day of , 20 Printed naine Notary Public in and for the State of Washington, residing at My appointment expires �'�� 3 torm Approvc;d by City Attorney ]Oi2013 ��,� oEsc�s�rio� �I PARCEL A: THE NORTH 677.44 FEET OF THE WEST 1/2 OF THE WEST 1/2 OF THE SOUTHEAST 1/4 OF THE SOUTHEAST 1/4 OF SECTION 3, TOWNSHIP 23 NORTH RANGE 5 EAST., W.M., IN KING COUNTY, WASHINGTON; EXCEPT THE WEST 130 FEET OF PORTION LYING SOUTH OF A LINE 339.5 FEET SOUTH OF THE NORTH LINE; EXCEPT THAT PORTION OF SAID NORTH 677.44 FEET LYING SOUTH OF THE FOLLOWING DESCRIBED LINE: BEGINNING AT THE INTERSECTION OF THE SOUTH LINE OF THE NORTH 677.44 FEET WITH THE EAST LINE OF THE WEST �, 1/2 OF THE WEST 1/2 OF THE SOUTHEAST 1/4 OF THE SOUTHEAST 'i/4 OF SAID ' SECTION 3; THENCE NORTH 87 DEGREES, 49 MINUTES AND 08 SECONDS WEST ALONG SAID SOUTH LINE A DISTANCE OF 89.01 FEET TO THE BEGINNING OF SAID LINE; THENCE NORTH 67 DEGREES, 07 MINUTES, 57 SECONDS WEST A DISTANCE OF 119.88 FEET TO INTERSECTION OF THE EAST LINE OF THE WEST 'i30 FEET OF THE SOUTHEAST 1/4 OF THE SOUTHEAST 1/4 OF SAID SECTION 3, SAID INTERSECTION BEING TERMINUS OF LINE; EXCEPT PORTION, IF ANY, CONVEYED TO JAMES L. DIXON, ET UX, BY DEEDS RECORDED UNDER RECORDERS NOS. 6468344 AND 7207120398. PARCEL B: A NON-EXCLUSIVE EASEMENT FOR INGRESS AND EGRESS AS CREATED BY INSTRUMENT RECORDED AS RECORDING NUMBER 7609140487. TAX PARCEL NUMBER: 032305902101 � I I � ; + I I I � I I � i , I I � I BLOCKS�I FOf�RLOTS 1!A 3PL�SB�E � U�'ED FOR FLOW CONTROL BMP �..—.— �.-- L � + �-. �- = ` .- --��T T _ _ -. �=. ........�... �.,., �. ` ^ CTYP) I , : _•-�. _ -�- • -- , e � - . f/ , ---- �!'-�°�--- � � � ,zr� � _�r s /l I � ;�rT//!�/l,UlllJ�prin�nr�/fll.lU//�/1/ I -�� -�--- - -�.�� __� _-- -- -, ,_ ..�...^-�.._... __ - �, � . _ zZ _�-__� - ----- ........ .....: .... .... . ... .............. z, , � --- _____I-�-�-�--..� ...............:::::�. . : �5 . -. ..__� . . ..� ... .. ....... . .. ...... I . ..... .. . . ..... .... . .... ( .... ... � I \ r-------� ��r.i��.:� � i � �� r-- ----� � � I � I � i i �� :�:�:�: � �3 � I I � ai � � .. . , � ::_t:: , � , .. . � � � •1�. � � �______� ,::. -. � ______J I � I J O� I--- ��---�_I i�r.��i. � ------� . � f ��- -- — --- - � � 1�:.: ; � � ,A„ c � � � �2 � ; � mi � � � � , .. .. ... ... I ' _ _ ' ' ::: ' ------' � ZI �______� �T 1i i � I fi mI -----� H "'�::: N r-------� t-+ � �� !"'' I I :.: I I � - --- - _ _� � � i i i .� "'� i i i DETENTION VAULT �J i � 3 � � � � �1 � I ... ... . �::.�:.: , ... ... B S C D/SPERSION� V/A i J ' =•:� •:: � � ' � ----- i i •:. :. , i i SPLA�'(-1 BLOCKS FOR EACH ' � , .:::::: , � , � . I ':. ':' �.______� RESIDEN�E TO BE USED�OR �-------� ,� ti �– – FLO,W CONTROL BMP ( YP.) i ; :;�:, � �� i I , , \ �� ` � 4 '� � �0 � � � - - � ` -- --- — � '�� " t„'-1�:°_• � i `•;��, t i , '�;�; i i •::! i i -- I � \ <,\,. � � :.i::. �-----------� — • ... �� 1 ::'.:':. r______-___- ' � � y:" �_______ _� � I I ;� ..�: �' i � ��I � + g ' � � ' � / � �,� �= i , �=� ,�'� I � ::�: i i �a.. ,:j I ... ,� �------- .. ... .... / �`,�, :, ::.r::. ---= ,�, ....... �----------� � \ / / �__ .--r -- � : � i � � �.\\ / I i i 8 i — -- -- -- ----� ...... J �, � ' i � � ' ' ' :::. , � �� , , � � .� / � �__________� I I . .. ... :: ::: � ... � ::.:�:. �----------� �\ � I i�r.L..., � I � I I �� / -I- --- — - N ; 7 i , \ , � , � � :::�::� 4 � � , � \ �� ' �� ::r�:.: �-------� ; � � �� Ti;------� -- --- -- --I � \ Z�� I � '� � � Q1. I :.'.".'.I.".':.:.::::I.'.'::"r.:'. i 1 � I � � ....J::::::..::.: I � ! . � ♦ Z � � � 7 �6' � � � N I i i i i � \ N\ _ _�. "__ _ �.�p�..��.:.:.:'.':....::'.�. � L_-- � ; I \ '.'.'I'::.�::.']::t::.::' _J I � \ � � I . . r��- , � \Q \ �, + - - - �.,1:::• i -� -- -- - I � �� r� � � � I -�"- --�-I \,� , �y\ � �' � � J II . _ _ y I ( � , I 5� ' I � ` � I \� �� i � I `� --------' i i `.� � tl� � � s�:��. � T� I � I � � � ', \� � \ � �(—�———---�1 i � i � EXH/B!T A N O RT H GRAPHIC SCALE 0 50 100 150 �� 1 INCH = 100 FT. �- -- EXHIBIT B II'! OPERATION AND MAINTENANCE SCHEDULE I Detention Vault I� Routine maintenance for the detention vault consists of periodically removing �'� accumulated sediment and debris; checking the inlet/outlet pipes and removing any �� sediment or debris blocking the pipes; properly removing/disposing of any visible oil sheen from the wafer and removing accumulated sediment from the vault bottom. Perform inspections of all components quarterly during the first year of operation, then at least annually thereafter. The detention facility should also be inspected after major storm events. Basic Dispersion via Splash Blocks ' Dispersion devices must be inspected annually and after major storm events to identify and repair any physical defects. When native soil is exposed or erosion channels are present, the sources of the erosion or concentrated flow need to be identified and mitigated. Concentrated flow can be mitigated by leveling the edge of the pervious area and/or realigning or replenishing the rocks in the dispersion device, such as in rock pads and gravel filled trenches. The vegetated area over which runoff is dispersed must be maintained in good condition free of bare spots and obstructions that would concentrate flows.