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Home My WebLink AboutMiscD.R. STRONG CONSULTING ENGINEERS Technical Information Report (TIR) for Saddlebrook Div. II 13422 1561h Avenue SE, Renton, Washington DRS Project No. 13030 City of Renton File No. LUA 13-XXX Owner/Applicant ACH Homes, LLC 9675 SE 36 1h Street, Suite 105 Mercer Island, Washington 98040 Report Prepared by lbliiJ) D. R. STRONG Consulting Engineers, Inc. 10604 N.E. 38th Place, Suite 232 Kirkland WA 98033 (425) 827-3063 © 2013 D. R. STRONG Consulting Engineers Inc. Report Issue Date May 20, 2013 MAY ? ~ 1013 TECHNICAL INFORMATION REPORT Saddlebrook TABLE OF CONTENTS SECTION 1 ••••••••••••••••.•.••••••••••••••••••••••••••••••••••••••••••••••••.••••••••••••••••••••••••••••.••••••••••••••••••••••••••••••••••••••••••••••••••• 1 PROJECT OVERVIEW:........................................... .. ................................ 1 PREDEVELOPED SITE CONDITIONS:.................................................. .. ................................ 1 DEVELOPED SITE CONDITIONS:............................................ ... .. ................................. 1 NATURAL DRAINAGE SYSTEM FUNCTIONS:.................................................... ... ......... . ..... 2 FIGURE 1. TIR WORKSHEET.......................................................... . ..... 3 FIGURE 2. VICINITY MAP............................ . ... ......... ... . .................. ............. ...... ........... .. ...... 6 FIGURE 3. DRAINAGE BASINS, SUBBASINS, AND SITE CHARACTERISTICS ............................ 7 FIGURE 4. SOILS ............................................................................................................................... 8 SECTION 11 ................................................................................................................................................. 10 CONDITIONS AND REQUIREMENTS SUMMARY.......................... . ................. 10 SECTION 111 ................................................................................................................................................ 12 OFF-SITE ANALYSIS ............................................................................................................................. 12 SECTION IV ............................................................................................................................................... 13 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ........................ 13 EXISTING SITE HYDROLOGY (PARTA)..... . ................. 13 FIGURE 5. PREDEVELOPMENT AREA MAP...... . ........ 14 DEVELOPED SITE HYDROLOGY (PART B). .......... ...................... ...... .. ....... 15 BYPASS AREA HYDROLOGY............................. . ............ 17 FIGURE 6. POST DEVELOPMENT AREA MAP.............. .. ....................................... 18 PERFORMANCE STANDARDS (PART C) ............................................................................................ 19 FLOW CONTROL SYSTEM (PART D) ....................... .... .. ............................................. 19 FLOW CONTROL BMP SELECTION ................................................................................................... 19 FLOW CONTROL SYSTEM ................................................................................................................... 20 WATER QUALITY TREATMENT (PART E) ..................................................................................... 28 FIGURE 7. DETENTION FACILITY DETAILS AND BAYFILTER SIZING ........................................ 29 SECTION V ................................................................................................................................................ 30 CONVEYANCE SYSTEM ANALYSIS AND DESIGN ............................ .. .. .............. 30 DEVELOPED 15-MINUTE TIME SERIES ........................ . . .............. 30 BACKWATER ANALYSIS .......................................... . BACKWATER ANALYSIS MAP ........................................................................................... .. . .. 32 . .. 34 BACKWATER ANALYSIS RESULTS ......................... . . .......... 35 SECTION VI ............................................................................................................................................... 39 SPECIAL REPORTS AND STUDIES ............. . . ................................... 39 SECTION VII .............................................................................................................................................. 40 OTHER PERMITS, VARIANCES AND ADJUSTMENTS ....................................... 40 SECTION VIII ............................................................................................................................................. 41 ESC PLAN ANALYSIS AND DESIGN (PART A)....... . ........ 41 SWPPS PLAN DESIGN (PART B) ........................................................................................................ 41 SECTION IX ............................................................................................................................................... 43 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ................. 43 STORMWATER FACILITY SUMMARY SHEET .................. 44 SECTION X ................................................................................................................................................ 46 © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report Saddlebrook Div. II Renton, Washington OPERATIONS AND MAINTENANCE MANUAL. ................................................... . ........ 46 APPENDICES ............................................................................................................................................. 47 APPENDIX "A" LEGAL DESCRIPTION .. APPENDIX "B" BOND QUANTITY WORKSHEET ...................... . APPENDIX "C" OPERATIONS AND MAINTENACE MANUAL .. . APPENDIX "D" CSWPPP .. © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report . ................ 48 . .. 49 50 . ...... 51 Saddlebrook Div. 11 Renton, Washington SECTION I PROJECT OVERVIEW: The Site is located at 13422 1561 h Avenue SE in Renton, Washington, also known as King County Tax Parcel Number 366450-0250. The Project is the subdivision of this existing parcel zoned R4 (0.89 ac. total) into three single-family residential lots, per the City of Renton's (City) short plat process. The Site will utilize the detention facility within Saddlebrook Div. I to meet flow control requirements. The pond will be redesigned to Level Three Flow Control Standards. The Project will meet the drainage requirements of the 2009 King County Surface Water Design Manual (Manual), as adopted by the City. PREDEVELOPED SITE CONDITIONS: Total existing Site area is approximately 38,715 s.f. (0.89 ac). Total proposed Project area is 41,095 s.f. (0.94 ac) which includes 2,380 s.f. (0.05 ac) for the right-of-way frontage improvements on 1561h Avenue SE. The Parcel is currently developed with a single-family home, covered patio and a gravel driveway. The remainder of the Site is lawn, landscaping, and scattered trees. The 0.89 acre parcel contains a single natural discharge point near the southwest corner of the Site. The Site sheet flows towards the southwest corner of the Site and into the right-of-way. From there, it is collected into the conveyance system within 1561 h Avenue and is conveyed south. For the purpose of hydrologic calculations, the entire Site is modeled as till forest. DEVELOPED SITE CONDITIONS: The applicant is seeking approval to subdivide 0.89 acres into three single-family residential lots (Project), with lot sizes ranging from approximately 10,249 to 10,983 s.f. All existing improvements will be demolished or removed during plat construction. The proposed impervious surface area will include a new shared driveway tract with 16 feet of pavement. Impervious surface are will also include offsite half-street improvements along 1561h Avenue SE. The proposed shared driveway improvements total approximately 4,474 s.f. The three single-family residences and their driveways combined will create approximately 10,875 s.f. of impervious area (reduced from maximum allowable, see next paragraph for details). Post-developed impervious areas including driveways, roofs, and site frontage improvements total approximately 17,729 s.f. (includes Bypass area). The remainder of the Project will be modeled as till grass totaling approximately 23,366 s.f. (See Section IV) 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 12.75% to 13.66% of impervious area for each lot. Also, each lot will be restricted to an area less than 4,000 s.f. (see table below). Additionally, use of Basic © 2013 D. R STRONG Consulting Engineers Jnc. Technical Information Report Saddlebrook Div. II Renton, Washington Dispersion allows for a 50% flow control BMP sizing credit which was used in detention facility calculations. See table below for lot area, restricted impervious area per lot, and percent impervious mitigated per Jot. ROOF AREA ROUTED TO RESTRICTED IMPERVIOUS TOTAL AREA PERCENT IMPERVIOUS LOT NO. LOT AREA (S.F.) SPLASH BLOCK (S.F.) AREA PER LOT MITIGATED MITIGATED 1 10249 1400 3505 1895 18.49 2 10983 1400 3485 1915 17.44 3 10877 1400 3885 1515 13.93 All surface water runoff from impervious surfaces will be collected and conveyed to a storm detention pond located within Tract "A of Saddlebrook Div. I. From there, runoff will be conveyed through a BayFilter vault before entering the existing conveyance system within 1561h Avenue SE. NATURAL DRAINAGE SYSTEM FUNCTIONS: A review of the SCS soils map for the area (see Figure 4, Soils) indicates Alderwood gravelly sandy loam with 6 to 15 percent slopes (AgC). Per the Manual, this soil type is classified as "Till" material. The SCS Soil series descriptions follow Figure 4. In evaluating the upstream area, we reviewed the existing offsite analysis and King County IMAP aerial topography and imagery and conducted field reconnaissance and have concluded that upstream tributary area for the Site is negligible. © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 2 Saddlebrook Div. II Renton, Washington FIGURE 1. TIR WORKSHEET King County Department of Development and Environmental Services TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Project Owner: ACH Homes, LLC Address/Phone: 9675 SE 36 1h Street, Suite 105 Mercer Island, Washington 98040 (206) 588-1147 Project Engineer: Maher A. Joudi, P.E. Part 2 PROJECT LOCATION AND DESCRIPTION Project Name: Saddlebrook Div. II Location: Township: 23 North Range: 05 East Section: 14 D. R. STRONG Consulting Engineers Inc. Address/Phone: 10604 NE 38 1 h Place, Suite 232 Kirkland WA 98033 (425) 827-3063 Part 3 TYPE OF PERMIT APPLICATION D Subdivision ~ Short Subdivision ~ Clearing and Grading D Commercial D Other: Part 4 OTHER REVIEWS AND PERMITS D DFWHPA D Shoreline Management 0 COE404 D Rockery D DOE Dam Safety D Structural Vault 0 FEMA Floodplain D Other: D COE Wetlands Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community: Newcastle Drainage Basin Lower Cedar River © 2013 D.R. STRONG Consulting Engineers lnc. Technical Information Report 3 Saddlebrook Div. ll Renton, Washington Part 6 SITE CHARACTERISTICS 0River: D Floodplain D Wetlands D Stream: D Seeps/Springs D Critical Stream Reach D High Groundwater Table D Depressions/Swales D Groundwater Recharge D Lake: D Other: D Steep Slopes Part 7 SOILS Soil Type: Slopes: Erosion Potential: Erosive Velocities: Alderwood 6-15% Moderate Slow to Medium (AgC) ~ Additional Sheets Attached: SCS Map and Soil Description, Figure 4 Part 8 DEVELOPMENT LIMITATIONS REFERENCE LIMITATION/SITE CONSTRAINT ~ Level 1 Downstream Analysis None _____________ _ ~ Geotechnical Engineering Study D Environmentally Sensitive Areas D Level 2 Off-Site Stormwater Analysis ~ Level I Traffic Impact Analysis D Structural Report D Additional Sheets Attached Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION ~ Sedimentation Facilities ~ Stabilized Construction Entrance ~ Perimeter Runoff Control ~ Clearing and Grading Restrictions ~ Cover Practices ~ Construction Sequence D Other © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION ~ Stabilize Exposed Surface ~ Remove and Restore Temporary ESC Facilities ~ Clean and Remove All Silt and Debris ~ Ensure Operation of Permanent Facilities D Flag Limits of SAO and open space preservation areas D Other 4 Saddlebrook Div. II Renton, Washington Part 10 SURFACE WATER SYSTEM D Grass Lined Channel [2J Pipe System D Open Channel [2J Dry Pond D Wet Pond D Tank D Vault D Energy Dissipater D Wetland D Stream D Infiltration D Depression D Flow Dispersal D Waiver D Regional Detention Method of Analysis: KCRTS Compensation/ Mitigation of Eliminated Site Storage N/A Brief Description of System Operation: Runoff from impervious surfaces will be collected and conveyed to the detention pond in Tract A of Saddlebrook Div. I. From there it will be discharged to the existing conveyance system within 1561h Avenue SE. Facility Related Site Limitations: Reference Facility Part 11 STRUCTURAL ANALYSIS D Cast in Place Vault D Retaining Wall D Rockery > 4' High D Structural on Steep Slope D Other: Limitation Part 12 EASEMENTS/TRACTS [2J Drainage Easement [2J Access Easement D Native Growth Protection Easement [2J Tracts D Other: Part 13 SIGNATURE OF PROFESSIONAL ENGINEER I or a civil engineer under my supervision have visited the site. Actual site conditions as observed were -~ncorporated into this worksheet and the attachments. To the best of my knowledge rw information provided here is accurate. © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 5 Saddlebrook Div. II Renton, Washington i ! ' ' -~ ~<it'ICA --~ r • • l • ' I FIGURE 2. VICINITY MAP ' ' ! Renton ... '"'"""" I • ' ! l ' 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. © 2013 0. R. STRONG Consulting Engineers Inc. Technical Information Report 6 Sadd!ebrook Div. JI Renton, Washington FIGURE 3. DRAINAGE BASINS, SUBBASINS, AND SITE CHARACTERISTICS © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 7 Saddlebrook Div. II Renton, Washington I I I I I 1~-~ I L_ ,~- _____ ,f 0'· _('.. '-'--- ' • ~ , ·l1--._._ l TD~ J/89 AC~ . lun---_ --J -- /,. ::s: ,, -. - " re 2 I ' [ __ ! 1 1 339 LF FROM FAflTHEST 3 ~ '. j I UPSTREAM END fQ ' ---) ';:: . -, I -T>-____ ·1 '_, •_:_-1-_ t-_'---_ _· __ , -DE-T,_E ____ N_ TION POND, , j ~-----~-._'_c_i ___ /_1 J_r,wit.'-x-:. _-=---_ =J I --.~ . -"° •-1= ---1 ----. :~:------=:----,-__ .-·~----'-c ~--:-·-~ --------- --~-----~,_ .. ·>-1-n · 1, I',/_ :,1 ---- ~~XIS-:;;;; AND CON; 0 TRUC;;N - RUNOFF EXIT SITE HERE• - --- I ----] •-., ' j I ·. '_-1· : \~ -.,,_ !I l , I C ~~--------._--._Ji -~---__ -_---:,~~=-~ -c--·-~'----------. .,/1 =-/ ~ ---71----l i_'-; LEGEND SITE BOUNDARY 't\.. / 7 ---~-""'=== r" ,---·v- ·I [~~ --c_~~) ,_ J . J DEVELOPED RUNOFF .. Ef<I T SI TE HERE • I ~>I:, /. •I -, ' -: I !" ·1 ( 0 @ NORTH GRAPHIC SCALE 40 80 ' ' -- 1 INCH= 80 FT. 120 ---BASIN BOUNDARY R \2013 \0\13030\J\Drcwir1gs \PcsA\f<,,oort Figureq \01-.\_'-IG.31..1030 c;·~·q 5/3/2013 1;: 11: 23 AM PDT CC,'YRl'.-HT@ 2012 , JR. s~ROC<JG CONS·JL TING E'JGtNEERS 1'1::::. "' ili ~ (!) ~ ~~ ~ i::: s " 0: ii <:i l;) ~ i'.:: .... !':!2 ,q: 8j • i ~ ~ ~ ~ o' ~ • ~ ij ~ i! ~ ffi ~ ~ ! ! ~ • ij ffi ~ ~ ~ ~ 0 ~ I ~ t; .... ~ Q:: ~ ~ ~~~ (/) !::: lJJ ~ Cl) ::::s (!) :::: ~ ::c: ::c: ...... :C:~:i: ... '<c Cl) ;::;: Cl) '<c :;c .... ~~~ 5 i~~ 0 ~ &l~ a:: Cl) ~ lJJ !:Q Cl) ,._ a:: IJ.i ~ ..... Cl) Q a§ Q lJJ ~ ~ ~ DRAFrED BY: 't7.P DESIGNED BY: 't7.P PROJECT ENGINEER: IJAJ DA TE: (H,.JO.t.J PRO£CT NO.: 1,JO.JO ncuRE 3 I FIGURE 4. SOILS King County Area, Washington AgC-Alderwood gravelly sandy loam, 6 to 15 percent slopes Map Unit Setting Elevation: 50 to 800 feet Mean annual precipitation: 25 to 60 inches Mean annual air temperature: 48 to 52 degrees F Frost-free period: 180 to 220 days Map Unit Composition Aldeiwood and similar soils: 95 percent Minor components: 5 percent Description of Alderwood Setting Landfonn: Moraines, till plains Parent material: Basal till with some volcanic ash Properties and qualities Slope: 6 to 15 percent Depth to restrictive feature: 24 to 40 inches to dense material Drainage class: Moderately well drained Capacity of the most limiting fayer to transmit water (Ksat): Very low to moderately low (0.00 to 0.06 in/hr) Depth to water table: About 18 to 37 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Very low (about 2,5 inches) Interpretive groups Land capability (nonirrigated): 4s Typical profile 0 to 12 inches: Gravelly sandy loam © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 8 SITE Sadd!ebrook Div. II Renton, Washington 12 to 27 inches: Very gravelly sandy loam 27 to 60 inches: Very gravelly sandy loam Minor Components Norma Percent of map unit: 1 percent Landform: Depressions Bellingham Percent of map unit: 1 percent Landform: Depressions Seattle Percent of map unit: 1 percent Landform: Depressions Tukwila Percent of map unit: 1 percent Landform: Depressions Shalcar Percent of map unit: 1 percent Landform: Depressions © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 9 Saddlebrook Div. II Renton, Washington 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: The Site will discharge at its natural discharge location. • C.R. #2 -Offsite Analysis: An Offsite Analysis is included in Section Ill. The Analysis describes the Site's runoff patterns in detail. • C.R. #3 -Flow Control: The Project is required to adhere to Level 3 Flow Control Standards per Adjustment 2012-03 for Saddlebrook Div. I. A detention pond will provide flow control as required for both drainage basins within Saddlebrook Div. I as well as Saddlebrook Div. II. The Project is required to "match developed discharge durations to predeveloped durations for the range of predeveloped discharge rates from 50% of the two-year peak flow up to the full 50-year peak flow." (KCSWDM, Sec. 1.2) Also match developed peak discharge rates to predeveloped peak discharge rates for the 2, 10 and 100 year return periods. Furthermore, the Project must meet the Flow Control BMP requirements as specified in Section 1.2.3.3 of the Manual. The Project will utilize basic dispersion and restricted footprint to meet this requirement. • C.R. #4 -Conveyance System: New pipe systems and ditches/channels are required to be designed with sufficient capacity to convey and contain (at minimum) the 25-year peak flow, assuming developed conditions for onsite tributary areas and existing conditions for any offsite tributary areas. Pipe system structures and ditches/channels may overlap for runoff events that exceed the 25-year design capacity, provided the overflow from a 100-year runoff event does not create or aggravate a "severe flooding problem" or "severe erosion problem" as defined in C.R. #2. Any overflow occurring onsite for runoff events up to and including the 100-year event must discharge at the natural location for the project site. In residential subdivisions, such overflow must be contained within an onsite drainage easement, tract, covenant or public right-of-way. The proposed conveyance system was analyzed using the KCBW program, and is capable of conveying the 100-year peak storm without overlapping 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 facility will be the responsibility of the City. An Operation and Maintenance Manual is included in Section X. • C.R. #7 -Financial Guarantees: Prior to commencing construction, the Applicant must post a drainage facilities restoration and site stabilization financial guarantee. For any constructed or modified drainage facilities to be maintained and operated by the City, the Applicant must: 1) Post a drainage defect and maintenance financial guarantee for a period of two years, and 2) Maintain the drainage facilities during the © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 10 Saddlebrook Div. II Renton, Washington 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. Stormwater runoff will be collected in the detention pond and then conveyed through a BayFilter vault which will accommodate water quality requirements. • 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. © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 11 Saddlebrook Div. II Renton, Washington SECTION Ill OFF-SITE ANALYSIS A Level One Downstream Analysis was prepared by DR Strong Consulting Engineers. A copy has been included in this Section. © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 12 Saddlebrook Div. II Renton, Washington LEVEL ONE DOWNSTREAM ANALYSIS for SADDLEBROOK DIV. II Short Plat 13422 1561 " Avenue SE, Renton, Washington DRS Project No. 13030 Renton File No. LUA 13-XXX Owner/Applicant ACH Homes, LLC 9675 SE 35th Street, Suite 105 Mercer Island, WA 98040 Report Prepared by il!ki.11 D. R. STRONG Consulting Engineers, Inc. 10604 N.E. 38th Place, Suite 232 Kirkland WA 98033 (425) 827-3063 ©2012 D.R. STRONG Consulting Engineers Inc. Report Issue Date May 14, 2013 LEVEL ONE DOWNSTREAM ANALYSIS SADDLEBROOK DIV. 11 TABLE OF CONTENTS TASK 1 DEFINE AND MAP THE STUDY AREA ......................................................... 1 TASK 2 RESOURCE REVIEW ..................................................................................... 5 TASK 3 FIELD INSPECTION ..................................................................................... 15 Upstream Tributary Area ............................................................................................ 15 General Onsite and Offsite Drainage Description ...................................................... 15 TASK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS ... 16 Drainage System Description ..................................................................................... 16 Downstream Path ................................................................................................... 16 TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS ......................... 21 List of Figures Figure 1 Vicinity Map ....................................................................................................... 2 Figure 2 Site Map ............................................................................................................ 3 Figure 3 King County iMap Topography ......................................................................... .4 Figure 4 Streams and 100-Year Floodplains and Floodway ............................................ 6 Figure 5 King County iMap Wetlands .............................................................................. 7 Figure 6 King County iMap Erosion Hazard Areas .......................................................... 8 Figure 7 King County iMap Landslide Hazard Areas ....................................................... 9 Figure 8 King County iMap Seismic Hazard Areas ........................................................ 10 Figure 9 FEMA -Flood Insurance Rate Map ................................................................ 11 Figure 10 King County iMap Drainage Complaints ........................................................ 12 Figure 11 USDA King County Soils Survey Map ....................................................... 13 Figure 12 Downstream Map .......................................................................................... 18 Figure 13 Downstream Table ........................................................................................ 19 ©2013 D.R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat Page i ofi City of Renton TASK 1 DEFINE AND MAP THE STUDY AREA This Offsite Analysis was prepared in accordance with Core Requirement #2, Section 1.2.2 of the 2009 King County Surface Water Design Manual (Manual). The Site is located at 13422 1561h Avenue SE in Renton, Washington. See Figure 1, Figure 2, and Figure 3 for maps of the study area. ©2013 D. R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Sadd!ebrook Div. II Short Plat Page 1 City of Renton FIGURE 1 VICINITY MAP SITE • I ~ 0 R-4 Sli1l1Sis;r • i • R-4 R-4 SE ll!STL.h" R-4 "-~ R-4 SE ID>tCPL ! S£1ll>cOCT • •• • 1'. R-4 I NE!STPI. • l,'\;1STIST a ;; SllilJCTifST § :1 i I ·' NE1S'Tl>I. R-4 ,.,,rn • f """"~ ! I • Renton • ""'~ R-4 ..... SE1JIITMS • """~ < I • • • ~ "'""' < • < SEl1'TIITI'II, ~ t I ~ """'~ \~ • • ~ < < Sli~OPL SE:¥lOPl· I 81811 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 sa!e of this map or information on this map is prohibited except by written permission of King County. ©2013 D.R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat Page 2 City of Renton ©2013 D. R. STRONG Consulting Engineers Inc. Level One Downstream Analysis FIGURE 2 SITE MAP Saddlebrook Div. II Short Plat Page 3 City of Renton I I I I I I I I I I I I I I I I I I I I~ Li' ,t ct : :2· 1_ -· - \ 1 \ 1 I, , I 1 ',' 1-, 'jl _/'' ! I ...._1'_,,.... 1 J1+L,J _\ , _ ,J.-J,, Jl'jl' --'<', -,-" ' '' -,, .. ,, - 1 (f i :/ \iii'': 11 ' i_ 'I'- -'i ·::~ ,·'' _I I \ I" • 1<~,,{-c,;-·_c· __ -= -3, -· __ \ -•• \' II I -1:' :', ,s i \--------~;--~~,,·-' 1;, ;,-~, X------X~ ~' -' IL , 1 '·,I , ,ci i'(u -~--· · '-\--: ",,>>-,_ -~ ---_ , •. I: 1 • I I,);'-';' :r \ I !"'---' '". -' ,---C ,-,/ ,''.' -' I • -' I' ,, • ' ' . , ,,-, ' -~ ., ,, , ----------------------~ I i t,,! \ i j ,; ---,,, ,,,, :::, , : 1'' ' \ -, Go{ 'I ~i ): \ -,-h" ---f,~ t > : < 1 : ; ! 1 ___ ,---'i_-'7:',1 _ ,,--) ,~,.,--..._ C I ' , ::c --,---\ ,,----cl"£· /_ .______:>\ F ' :: '1'· '' < _C •' ,-;"\'{' C -·>,, ! \~ I Hi%, . ' "' lii,I I. 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"; ~ , ~ " " " -~ ffi :ii:: Ii.. ! t ij " i;i " I ~ I ~ ~ -. ffi ! ~ Cl) :::: ~ :::::.: Cl. -.J -~~ Q !IJ '( ~ ~ I!:! 0 CJ) ii> 0 lt a:: Q fB ~ Q ~ DRAFTED BY: Ill' DESIGNED BY: U PROJECT ENGINEER: ltlAI DATc:: Of.&0 PROJECT NO.: ,... R:\'OU\0\UOJO\J\O,ow!ogs\Bose\Ropoc> F;g,<es\OHDS_FIG2_cwg 5/3/20'3 2 39 30 PM PDT [ ~GURE, 2 I COPYRIGHT @ 2012, !).R._ ST'3._0N_Q_ C~SULTING ENGINEERS INC FIGURE 3 KING COUNTY IMAP TOPOGRAPHY Ill Highlighted Feature -. County Bounda ,y ·-X Mountain Peaks Contours (5ft dark) /V 100:500;1000 ;V Othm ©2013 D. R. STRONG Consulting Engineers Inc. Level One Downstream Analysis V Renton Legend Highways D Streets I'/ HighW3)' Artcriilts La.cal Parcels Saddlebrook Div. II Short Plat Lakes and Large Rivers Streams Page 4 City of Renton TASK2 RESOURCE REVIEW • Adopted Basin Plans: May Creek Basin Action Plan was adopted in April 2001. • FloodplainlFloodway (FEMA) Map: No floodplains exist on site, See Figure 9. • Other Offsite Analysis Reports: Saddlebrook Div. I • Sensitive Areas Folio Maps: See Figures 4-8 for documentation of the distance downstream from the proposed project to the nearest critical areas. Included, are sections of the King County Sensitive Areas Folio which indicate the following: • Figure 4 Streams and 100-Year Floodplains and Floodway: There is a Class 2 Stream within one mile of the Site along the downstream path. • Figure 5 Wetlands: There are no mapped Wetlands within one mile of the Site along the downstream path. • Figure 6 Erosion Hazard: There are mapped Erosion Hazard Areas within one mile of the Site along the downstream path. • Figure 7 Landslide Hazard: There are mapped Landslide Hazard Areas within one mile of the Site along the downstream path. • Figure 8 Seismic Hazard: There are mapped Seismic Hazard Areas within one mile of the Site along the downstream path. • DNRP Drainage Complaints and Studies: As shown in Figure 10,there are no drainage complaints, within the last 10 years, within 1 mile of the Site along the downstream path. • Road Drainage Problems: None noted. • USDA King County Soils Survey: See Figure 11. • Wetlands Inventory: Vo/. 3South (1990) -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: None applicable to this site. • Basin Reconnaissance Summary Reports: None available at this time ©2013 D.R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat Page 5 City of Renton FIGURE 4 STREAMS AND 100-YEAR FLOODPLAINS AND FLOODWAY SITE Ill Highlighted Feature -, County Boundary ,t '-X Mountaln Peaks Highways ;,/ Streets /V Jlighw~ .......... D lo<>' , /s" Parcels D ©2013 D.R. STRONG Consulting Engineers Jnc. Level One Downstream Analysis Legend SAO Stream c .... 1 Cbn2Paranni;JJ C Ins 2 Salmon id c1.,n 3 Und.nsifiod Lakes alld Large River& Streams 100 Year Floodplaln ; " . ---.-.,_):;! Knm,._ -~ • Saddlebrook Div. II Short Plat Page6 City of Renton " " ~ • " t ' ! ;; ~ ' ~ ·-x ( :ii ~; ~ 1:m11PL • • s1 t ~ -; § i ..• • f • a • ~ i • ' .-" a ,$' .. + ! Highlighted Feature County Boundary Mouhtain Peaks Highways Streets t-lig.hW3)' (cont) FIGURE 5 KING COUNTY IMAP WETLANDS ' • ] / SITE SIE1l!ST/'l ,....._,._.,, l~P.IJ ' -;;,;;;,,;;,---"'i!l:'.lll~__J 11£ 1ST Pl SlirlTS'TST ~ f • • ~ f ~ 3 g g ./' KE \STST if "' ~-~ ~-~ Legend La<al Parcels D Lakes and large River& 1 .,-./ Straams lz3 SAO Wetland ,p • • ~ Sli IGTHST ©2013 D.R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat • ' i • ' ! ' ' ' I ' a i 4 ( "' :.~_)3,JT ' ' ' .L -..... ~-----.. , , r -" ! .~ r I Page 7 City of Renton FIGURE 6 KING COUNTY IMAP EROSION HAZARD AREAS SITE " \ " • < ~ Ill -1 I_ X ( Highlighted Feature County Boundary Mountain Peaks Highways Streets 11,gh~ (cont) ! ! D ;./ ©2013 D. R STRONG Consulting Engineers Inc. Level One Downstream Analysis SE !llTflST Arlcri:ib Loc,i ii·-··i41-:<;_E.l4~l!:I St • • § ! ,0 Legend Parcels • • ~ • Lakes and Large Rivers Streams SAO Eror;ion ' SE1"ffi!ST • • < ~ i i S6l.milff Saddlebrook Div. II Short Plat • • < • i § Page 8 City of Renton FIGURE 7 AP LANDSLIDE KING COUNTY IM SITE "-,· ., ;, '~'//, ·-~:\-';; .!'.//.;' Ill -. ·-x Highlighted Feature County Boundary Mountain Peaks Highways Streets IHgh~ (oont) Legend L<,cad D Parcels Rivers Lake& and Large / streams / SAO Landslide ~ . ineers Inc. ONG Consulting Eng HAZARD AREAS ©2013 D. R ST~tream Analysis Level One Down Saddlebrook D1v. I . I Short Plat Page 9 City of Renton FIGURE 8 KING COUNTY IMAP SEISMIC HAZARD AREAS SITE " ;[ Renton • I , '<! . • z 8 j, ~ • g t ~ /* I 5€2Ht>cT . / ""'°" SE2HOCT "''"'"' Ill Highlighted Featuro -, County Boundary ,_ X Mountain Peaks Highways D Streets // ; Highw.1)' ~ (cont) ©2013 D.R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Legend Meri:iit; Local Parcels SI> IJm1 ST SE'!llTHSf '""'" r---.,1 k1lST/fPL :Ii. Lakes and Large Rivers Streams SAO Seismic Saddlebrook Div. II Short Plat '" Page 10 City of Renton s FIGURE 9 FEMA-FLOOD INSURANCE RATE MAP l);f;(i CJ CJ ZONE X 1J8Tf! I LEGEND ~Pr(]-\l IHJUIJ H~?-.>.RD ,\f,([.\~ INUNP,\(Ll) ll',' ]rnl-YJ:,W HOOi) ZONE A ZONE AE ll,I" , .. ,,.r ,.r, ,,,,.,,,.,~.,,,,,,,.~.i ZONE AH 11,,,d nr I'" I,-,,~ •,J.,.,.,11·, "I i,,N' ]!,.,(' ,!,·,Hi••" (iej,·,m">,<I ZONE AO d,-;,:h , I "" l k~-, u,,,,,1;, ..f~·d ZONE A99 ZONE V "" •I•·;>"~ :, "·"''; .,·.n.1~,· ,~ l~i,,. ,:,1o•,m,~,·d. r,,. .,,,,1-.. , .,f!,.,,.,1 i.,,, n,,.,!,·'.~ >,•l<s<!w, ,,,~, ,l,·t<·""""'I ( , .. ,~.,! ~.,,,,1 ,,,,,, "'""'" h,,m,I '"·"·" ,UI"'" ,,., hN' ,1,.,1 ,,I,,.,,""'' dc,,,,.,,,,,,.,I Fl.()()D\V.W Af(b\S IN zOr-.l A( OHitR fl ()OD ARFA~ ZONE X V,·a• d '-0" )'"' 11 .. ,,1-.,,,.J, "' JC~)-\u' ,l<a,d ~,t:, ·'"''•'ilC cl,·,<h, ,,( l.-,, ,be, 1 h,, "' '"'h "'·""'"'' "~'•" le-,. 11,,,, 1 ><IY•"'' rr,le: ,,,,,f '"'"'°' p,~•,,,:,.,cf 1,1 11"<"-' /,i,o, hM·"'~" ol,~1 onirn AR~AS ZONE X ZONE 0 ·'"'-'> ,f<-1,,,n,;ne<J '" 1~, (nO~~<' 5lM}-I'"' 1/,,dp:,,,n. ,,,,." ,, .. o;,h '''""! ,.,,.,.,1, ., .. ,, u,·,k:,·rm·m~I ©2013 D.R. STRONG Consulting Engineers Inc. Level One Downstream Analysis 14 1:IBTH - Saddlebrook Div. II Short Plat - \ Page 11 City of Renton Ill -, I - X /I' FIGURE 10 KING COUNTY IMAP DRAINAGE COMPLAINTS SITE ~ Renton " I I § ! i 4' I 4" ,s,"' SEo'M>CT S0l1etod Puco11 County Boundary Mountain Ptak• Hlgl'lw1y1, Incorporated Arna Streets (cont) 'I ~;~"s", ~."' ;j !5tl~Ct N, Legend lhgh....-, Artonahi Cod Parcol1 D l1kct1 and Largo Rlvon ;I Streamli l:J Drainago Complalnll 0 ©2013 D. R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat ,-.,,, se,.crwsr, i Page 12 City of Renton FIGURE 11 USDA KING COUNTY SOILS SURVEY MAP AgC-Alderwood gravelly sandy loam, 6 to 15 percent slopes Map Unit Setting • Elevation: 50 to 800 feet • Mean annual precipitation: 25 to 60 inches • Mean annual air temperature: 48 to 52 degrees F • Frost-free period: 180 to 220 days Map Unit Composition • Alderwood and similar soils: 95 percent • Minor components: 5 percent Description of Alderwood Setting • Landform: Moraines, till plains • Parent material: Basal till with some volcanic ash • Properties and qualities • Slope: 6 to 15 percent • Depth to restrictive feature: 24 to 40 inches to dense material • Drainage class: Moderately well drained • Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately low (0.00 to 0.06 in/hr) ©2013 D. R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat Page 13 City of Renton • Depth to water table: About 18 to 37 inches • Frequency of flooding: None • Frequency of ponding: None • Available water capacity: Very low (about 2.5 inches) Interpretive groups • Land capability (nonirrigated): 4s Typical profile • 0 to 12 inches: Gravelly sandy loam • 12 to 27 inches: Very gravelly sandy loam • 27 to 60 inches: Very gravelly sandy loam Minor Components Norma • Percent of map unit: 1 percent • Landform: Depressions Bellingham • Percent of map unit: 1 percent • Landform: Depressions Seattle • Percent of map unit: 1 percent • Landform: Depressions Tukwila • Percent of map unit: 1 percent • Landform: Depressions Shalcar • Percent of map unit: 1 percent • Landform: Depressions ©2013 D. R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat Page 14 City of Renton TASK3 FIELD INSPECTION UPSTREAM TRIBUTARY AREA In evaluating the upstream area, we reviewed King County IMAP aerial topography and imagery and conducted field reconnaissance and have concluded that upstream tributary area for the Site is negligible. The upstream properties developed portions drain in southeasterly and southwesterly directions almost directly to the respective rights of way. GENERAL ONSITE AND OFFSITE DRAINAGE DESCRIPTION The 0.89 acre parcel contains a single natural discharge point near the southwest corner of the Site. The Site sheet flows towards the southwest corner of the Site and into the right-of-way. From there, it is collected into the conveyance system within 1561h Avenue and is conveyed south. Runoff from the developed Site will be collected and conveyed by a typical catch basin/ pipe network to a detention pond in the southwest corner of Saddlebrook Div. I. The pond will discharge to the conveyance system in 1561h Avenue SE. ©2013 D. R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat Page 15 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 Table located in Appendix A. The downstream area is located within the Cedar River; more specifically the Lower Cedar River sub basin. The downstream area was evaluated by reviewing available resources, and by conducting a field reconnaissance on July 12, 2012 under overcast conditions. Downstream Path Point "A" is the natural discharge point of the Site. Runoff exits the Site as sheet flow to the southwest. From Point "A" to Point "B", runoff heads southwest as sheet flow and into a Type 1 Catch Basin located along the east side of 1561h Avenue SE. (O' -±50') From Point "B" to Point "C", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 1 CB with a storm manhole lid. (±50'-±350') From Point "C" to Point "D", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 1 Catch Basin. (±350' -±440') From Point "D" to Point "E", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 1 Catch Basin. (±440' -±665') From Point "E" to Point "F", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 2 Catch Basin. (±665' -±680') From Point "F" to Point "G", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 2 Catch Basin. (±680' -±695') From Point "G" to Point "H", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 2 Catch Basin. (±695' -±770') From Point "H" to Point "I", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 2 Catch Basin. (±770' -±815') From Point "I" to Point "J", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 2 Catch Basin. (±815' -±890') From Point "J" to Point "K", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 2 Catch Basin. (±890' -±930') From Point "K" to Point "L", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 1 Catch Basin. (±930' -±945') From Point "L" to Point "M", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 1 Catch Basin. (±945' -±1,085') From Point "M" to Point "N", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 1 Catch Basin. (±1,085' -±1, 185') ©2013 D. R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat Page 16 City of Renton From Point "N" to Point "O", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 1 Catch Basin. (±1, 185' -±1,260') From Point "O" to Point "P", runoff continues south as pipe flow via a 12-inch PVC Pipe. The pipe connects to a Type 1 Catch Basin. (±1,260' -±1,360') Qualitative Analysis of the downstream path continued along 1561h Avenue SE. The analysis was concluded at the intersection of 1561h Avenue SE and SE 1441h Street. ©2013 0. R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat Page 17 City of Renton FIGURE 12 DOWNSTREAM MAP ©2013 D.R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat Page 18 City of Renton I I I I I I I I I I I I I I I I I I I -. I j ,--- _(_:,_~ _:::_: .. ' i, ~ -.. -~.~1,: · .... -. , ·. . . i ··I [-.~.,-.i!I , , 1s d _ .. ~:l ; ;, 'I-· I , 1 ID -I / J J ~- · 1't1r ~- _JhL_ J 111t I IM N 0 p NORTH GRAPHIC SCALE 0 100 200 400 1 INCH= 200 FT. "' lli !!! OJ ili "'"' ts ~ ~5 "'"' n: ;e c:i 8 .... ~ .... ~ • I ! ~ ~ !l: ~ ~ , ~ ~ ; i ~ ! i i i li " i ~ I • o 5 ~ ~ I i Cl.. !I) =::: :!i ~ s ::i;...., ..... ili ~ Q ~ <'( ~ !I) I:! 0 i !iS 0 Q lf: 0:: Cl Q m ..J ~ ~ DRA(T£D BY: nP DESIGNED BY: 'l'1P PROJECT £NG!NffR: MAJ DA TE: 04.30.13 PROJECT NO.: 13030 "'\2013\0\13030\3\0,ow;ccs\Bcse\Repcd f;q,,es\Of 3DSJfG'2dwg 5/j/2CU HS. '7 PM PD1 E72 · 1 COPYRIGHT © 2012, D.R. STRONG CONSULTING ENGll\EERS !NC. FIGURE 13 DOWNSTREAM TABLE Basin: Cedar River Subbasin Name: Lower Cedar River Subbasin Number: NIA Symbol Drainage Drainage Component Slope Distance Existing Potential Component Type, Description From site Problems Problems Name, and Size Discharqe Type: sheet flow, Constrictions, under capacity, ponding, See map swale, Stream, drainage basin, vegetation, cover, % 1 /4 mi=1,320 ft overtopping, flooding, habitat or organism channel, pipe, depth, type of sensitive area, volume destruction, scouring, bank sloughing, Pond; Size: diameter sedimentation, incision, other erosion Surface area A Natura! Discharge Sheet flow across southwest property ±0' None Observed None Anticipated Point corner A-B Southwesterly Sheet Sheet flow into a Type 1 CB ±50' None Observed None Anticipated Flow B-C Southerly Pipe Flow 12" PVC to a Type 1 CB ±350' None Observed None Anticipated C-D Southerly Pipe Flow 12" PVC to a Type 1 CB ±440' None Observed None Anticipated D-E Southerly Pipe Flow 12" PVC to a Type 1 CB =665' None Observed None Anticipated E-F Southerly Pipe Flow 12" PVC to a Type 2 CB ±680' None Observed None Anticipated F-G Southerly Pipe Flow 12" PVC to a Type 2 CB ±695' None Observed None Anticipated G-H Southerly Pipe Flow 12" PVC to a Type 2 CB ±770' None Observed None Anticipated H-1 Southerly Pipe Flow 12" PVC to a Type 2 CB ±815' None Observed None Anticipated 1-J Southerly Pipe Flow 12" PVC to a Type 2 CB ±890' None Observed None Anticipated J-K Southerly Pipe Flow 12" PVC to a Type 2 CB ±930' None Observed None Anticipated Page 19 ©2013 0. R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. 11 Short Plat City of Renton Observations of field inspector resource reviewer, or resident tributary area, likelihood of problem, overflow pathways, potential impacts. Trickle Flow Trickle Flow Trickle Flow Trickle Flow Trickle Flow Trickle Flow No Flow No Flow No Flow K-L L-M M-N N-0 0-P Southerly Pipe Flow 12" PVC to a Type 1 CB Southerly Pipe Flow 12" PVC to a Type 1 CB Southerly Pipe Flow 12" PVC to a Type 1 CB Southerly Pipe Flow 12" PVC to a Type 1 CB Southerly Pipe Flow 12" PVC to a Type 1 CB ©2013 D.R. STRONG Consulting Engineers Inc. Level One Downstream Analysis ±945' ±1,085' ±1,185' ±1,260' ±1,360' Saddlebrook Div. II Short Plat None Observed None Anticipated None Observed None Anticipated None Observed None Anticipated None Observed None Anticipated None Observed None Anticipated Page 20 City of Renton No Flow No Flow No Flow No Flow No Flow TASKS MITIGATION OF EXISTING OR POTENTIAL PROBLEMS A review of the King County Water and Land Resources Division -Drainage Services Section Documented Drainage Complaints within one mile of the downstream flow paths revealed no complaints within the last ten years. The project should not create any problems as specified in Section 1.2.2.1 of the Manual and therefore is not required to provide Drainage Problem Impact Mitigation subject to the requirements of Section 1.2.2.2. Project runoff will be collected and released per the Manual's requirements to accommodate Level 3 Flood Problem Flow Control and Basic Water Quality requirements. During construction, standard sediment and erosion control methods will be utilized. This will include the use of a stabilized construction entrance, perimeter silt fencing, and other necessary measures to minimize soil erosion during construction. R:\2013\0\13030\3\0ocuments\Reports\Preliminary\Level 1 OS 13030.docx ©2013 D. R. STRONG Consulting Engineers Inc. Level One Downstream Analysis Saddlebrook Div. II Short Plat Page 21 City of Renton SECTION IV FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN As previously stated, Saddlebrook Div. II will utilize the detention facility within Saddlebrook Div. I to meet flow control requirements. For purposes of facility sizing, Divisions I and II will be analyzed as one project. EXISTING SITE HYDROLOGY (PARTA) 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 SGS classification as shown in Figure 4. Soils. The entire Site is modeled as "Forest." Results of the KCRTS analysis are included in this section. Modeling input Land cover Entire Site Till forest (ac) 5.544 Till Grass (ac) 0.000 Wetland (ac) 0.000 Impervious (ac) 0.000 Scale Factor: 1.00 Time Step: Hourly Data Type: Reduced Project location: Seatac Total Area: 5.544 Table 1 Pre-Developed KCRTS Modeling Input Modeling results Entire Site Flow Frequency Analysis Time Series File:predev.tsf Project ~ocation:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak. (CFS) 0.350 2 2/09/01 18:00 0.095 7 1/06/02 3:00 0.259 4 2/28/03 3:00 0.009 8 3/24/04 20:00 0.154 6 1/05/05 8:00 0.268 3 1/18/06 21:00 0.226 5 11/24/06 4:00 0.447 1 1/09/08 9:00 Computed Peaks © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report --Peaks Rank (CFS) 0.447 l 0.350 2 0.268 3 0.259 4 0. 226 5 0.154 6 0.095 7 0.009 8 0.415 13 Return Period 100.00 25.00 10.00 5.00 3.00 2.00 1. 30 1.10 50.00 Prob 0.990 0. 960 0.900 0.800 0.667 0.500 0.231 0.091 0.980 Saddlebrook Div. 11 Renton, Washington FIGURE 5. PREDEVELOPMENT AREA MAP © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 14 Saddlebrook Div. II Renton, Washington I I I I I !:' I ( I I I I I I I I I I I I I I • i • ~· ... ·.· .. ···.· ... ··· .. \'··.··· ' '. --.. , -. . . -. -· -. . ., / ' ' . . ' ·, ' > ~ ~ -1. j._ . . ·. ·.· .. ·.. . ,,,,,,,,,,,,," i ! < . . . . ,··.··· . ) : . ·-.,-· _-_·--: . -"-~--.--·_. ·:_ ·,.-~ --"·._. __ -·:_, ·-_: _. -_--· __ ·_·_ _. ·._· .. _-: ~;-~e--~ - , ... I Ii ' I I I , I I AREA BREAKDOWN TOTAL EXISTING SITE AREA: TOTAL PROJECT AREA: TOTAL PROJECT DEVELOPMENT AREA: 228,512 SF. (5.25 ACRES) 241,515 SF. (5.54 ACRES) 241,515 S.F. (5.54 AC) MODELED AS TILL FOREST I I ' ' ' ' 'j i i' v 36 '.',·_ )( V X X Y { X X X-?(X X X/))'Y\:Iv-,. , LEGEND ---PROJECT BOUNDARY ~ TILL FOREST ··c.1 r , ·1,, ', I'• I,' •• , I @ NOR.TH GRAPHIC SCALE 0 40 80 120 1 INCH= 80 FT. R: \2013\0\1.30J0\.\\1r8'~-:ngs\8ose \;;>P.port H~1.res \01., 3FIG513030. dwg 5/3/20i 3 11: 07: 17 AM PD- COPYRI-JHT @ 2012, D.R. STRONG CONSUL TING [NGIN[ERS INC. "' lli !!l C, ~ ~~ Q j:: ~ 5 ~ ~ a: 0 <:i Cl .... ~ ),.. Et: ~ i ~ ~ ~ !k: ti ~ ~ ~ ~ ~ fJ ~ ffi Sc lL. ! ! ~ ~ i ~ ~ ~ 0 ~ I ~ ).. I 8~;s ..... 5 !-LI 1-C- l.lJ ~~~ a: ~~5: :J:: "'( (/) ::::: ~ i!: ~ s ii5 lg :.::· i5 (!) .... Q ::: £\I 1-C-~ § ~lG g ~-~ I L(j ..... is ~ {)RAFTED BY. YLP !HSIGN/:1) BY· YIP · 1-Ro.1r·c1 f-Nr;/NffR MAJ DA TE: 04.30.13 PROJECT NO.: 13030 f1GURt 5 ) DEVELOPED SITE HYDROLOGY (PART B) Soil type 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 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) 0.000 Till Grass (ac) 2.540 Wetland (ac) 0000 Impervious (ac) 2.857 Scale Factor: 100 Time Step: Hourly Data Type: Reduced Project location: Seatac Total Area: 5.397 Table 2 Developed KCRTS Modeling Input Detailed Impervious Area Breakdown: TOTAL LOT AREA= 169295 S.F. TOTAL R.O.W. AREA= 39688 S.F. TRACT A AREA (DIV. I) = 20130 S.F. TRACT A AREA (DIV. II)= 4412 S.F. TRACT B AREA (DIV. II)= 1554 IMPERVIOUS= 70278 S.F. 100% IMPERVIOUS= 39688 S.F. 50% IMPERVIOUS= 10065 S.F. IMPERVIOUS= 4412 S.F. IMPERVIOUS= 0 S.F. © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 15 PERVIOUS = 99017 S.F. 0% PERVIOUS 50% PERVIOUS = 10065 S.F. PERVIOUS = 0 S.F. PERVIOUS = 1,554 S.F. Saddlebrook Div. II Renton, Washington Modeling Results Saddlebrook Div. I and Div. II Flow Frequency Analysis Time Series File:rdin.tsf Project Location:Sea-Tar, ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.920 6 ?/09/01 2:00 0. 726 8 1/05/02 16:00 1.11 3 2/27/03 7:00 0.759 7 8/26/04 ?:00 0. 920 5 10/28/04 16:00 0.973 4 1/18/06 16:00 1.10 ? 10/26/06 0:00 1. 89 1 1/09/08 6:00 Computed Peaks © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report -----Flow Frequency Analysis------- --Peaks (CFS) l. 89 1.11 1.10 0. 973 0.920 0. 920 0.759 0. 726 1. 63 16 Rank 1 2 3 4 5 6 7 8 Return Period 100.00 25.00 10.00 5.00 3.00 2.00 1. 30 1.10 50.00 Prob 0.990 0. 960 0.900 0.800 0.667 0.500 0.231 0. 091 0.980 Saddlebrook Div. II Renton, Washington BYPASS AREA HYDROLOGY Modeling input Land cover Till forest (ac) Till Grass (ac) Wetland (ac) Impervious (ac) Scale Factor: Time Step: Data Type: Project location: Total Area: Entire Site 0.000 0.053 0.000 0.095 1.00 Hourly Reduced Seatac 0.148 Table 3 Bypass KCRTS Modeling Input Modeling results Bypass Flow Frequency Analysis Time Series File:bypass.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 0.028 5 2/09/01 2:00 0.056 1 100.00 0.990 0.023 8 1/05/02 16:00 0.036 2 25.00 0. 960 0.034 2 2/27/03 7:00 0.034 3 10.00 0.900 0.025 7 8/26/04 2:00 0.030 4 5.00 0.800 0.029 6 10/28/04 16:00 0.029 5 3.00 0.667 0.030 4 1/18/06 16:00 0.028 6 2.00 0.500 0.036 3 10/26/06 0:00 0.025 7 1. 30 0.231 0.056 1 1/09/08 6:00 0.023 8 1.10 0.091 Computed Peaks 0.049 50.00 0.980 The flow control facility is designed to compensate for uncontrolled bypass. The 1 OD- year discharge from the bypass areas is 0.056 cfs, which is less than the 0.4 cfs threshold. There should be no adverse downstream impacts to the downstream drainage system created by the runoff from the bypass. There is a bypass area associated with each TOA of Saddlebrook Div. I. For purposes of detention calculations, both bypass areas were used as the approved drainage adjustment calls for a combination of the TDA's. The onsite bypass areas satisfy all the requirements set forth in the Manual, Section 1.2 with the exception of TOA East (Saddlebrook Div. I) as it pertains to convergence with the downstream path of the facility within a quarter mile. This is further detailed in the following section. © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 17 Saddlebrook Div. II Renton, Washington FIGURE 6. POST DEVELOPMENT AREA MAP © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 18 Saddlebrook Div. II Renton, Washington I I I I I I I I I I I I I I I I I I I i I I - 1//// •i I, 0 ~ D D II AREA BREAKDOWN TOTAL EXISTING SITE AREA: TOTAL PROJECT AREA: LOT AREA (COLLECTED): IMPERVIOUS: TILL GRASS: ROW AREA (COLLECTED): IMPERVIOUS: TILL GRASS: TRACT A DIV. I AREA (COLLECTED). IMPERVIOUS: TILL GRASS: TRACT A/B DIV. II AREA (COLLECTED): IMPERVIOUS: TILL GRASS: BYPASS: IMPERVIOUS: TILL GRASS: / +I "---------"--• -+ -~cz:. -:-· _. ~. ..... ..... ..... ..... ..... ..... / / 228,512 S.F. (5.25 ACRES) 241,515 S.F. (5.54 ACRES) 169,295 S.F. (3.886 AC) 70,278 S.F. (1.613 AC) 99,017 S.F. (2.273 AC) 39,688 S.F. (0.911 AC) 39,688 S.F. (0.911 AC) 0 20,130 S.F. (0.462 AC) 10,065 S.F. (0.231 AC) 10,065 S.F. (0.231 AC} 5,966 S.F. (0.137 AC) 4,412 S.F. (0.101 AC) 1,554 S.F. (0.036 AC) 6,436 (0.148 AC) 4,143 (0.095 AC) 2,293 (0.053 AC) LEGEND ---PROJECT BOUNDARY ( I I . I I I L I 1 I !~~~~~~%?~~I~. 5 UJ ' ~ CJ) ~ "( i':: ~ - • -~-. . ~-..... "..... ..... ,.. -. V W ..... . . ..... " "" "' "' • .., TRACT"A""' • Q. 1, • • • • // ).-'.•,- /// /// I i1l ~····1~ • I~ ~ ~ "( i ::': @ NOR.TH GRAPHIC SCALE 0 40 80 120 1 INCH= 80 FT. R: \2013\0\ 13030\3\Crowings\Bose\Reµur/ Fi!Jores\01-Jn{;(,/.3030.dwg 5/11/2013 1:25:03 PM PDT :::CP'f:''ICHT (D 2012. CY SIRDrJG C~:~h'.Jl 1tt\G ENGIN[['xS INC. ~ Ill ;;,; (.') iii (.') (.') ~~ I!': s "'"' re ~ Ci 0 I- ~ I-:,.. " i ~ S M ~ ~;· ~ ~ ~ . ~ ffi 5( ~ ! ! ~ ~ j; ~ 1H ~ "If :ii; !!l C) ~ I Q:: (!) 0 a LJJ~ ~ a~e 0:: :::i C!) ::::: ~ ;;!:: ;;!:: s :i: ~ ~ -~ "( ::I: Cl U)~~ ~ @~~- ~ ~ f.::. 0 ,_,~nj m ~ -0:: LU ~ 2 ~ DRAFTED BY: YLP DES!GN[D BY: Yl.P PROJECT ENGINEER: MAJ DAT£: 04.30.13 PROJECT NO.: 13030 FIGURE: 6 J PERFORMANCE STANDARDS (PART C) The Project is required to meet the Level 3 Flow Control and Basic Water Quality Treatment requirements. The Level 3 performance requires the developed condition discharge rates to match the predeveloped rates ranging from 50% of the two-year peak up to the 50-year peak. Also match developed peak discharge rates to predeveloped peak discharge rates for the 2-, 10-and 100-year return periods. The Basic Water Quality Treatment goal is to remove 80% of TSS for flows or volumes up to and including the WQ design flow or volume. Conveyance criteria for the Project require that all new pipes be designed to convey and contain (at minimum) the 25-year peak flow. FLOW CONTROL SYSTEM (PART D) Both Saddlebrook Div. I and Div. II will utilize a detention pond meeting the Level 3 Flow Control Criteria. The King County Runoff Time Series (KCRTS) software was used to size the detention facility. The detention pond 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). Projects are required to first analyze the feasibility of dispersal and infiltration before choosing another method. The Site 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 12.75% to 13.66% of impervious area for each lot. Also, each lot will be restricted to an area less than 4,000 s.f. (see table below). ROOF AREA ROUTED TO LOT NO. LOT AREA (S.F.) SPLASH BLOCK (S.F.) 1 10249 1400 2 10983 1400 3 10877 1400 © 2013 D.R. STRONG Consulting Engineers lnc. Technical Information Report RESTRICTED IMPERVIOUS AREA PER LOT 3505 3485 3885 19 TOTAL AREA MITIGATED 1895 1915 1515 PERCENT IMPERVIOUS MITIGATED 18.49 17.44 13.93 Saddlebrook Div. II Renton, Washington FLOW CONTROL SYSTEM The Project will utilize one detention pond to meet Level Three Flow Control criteria for the Site. The King County KCRTS software was used to size the detention facility. Saddlebrook Div. I and Saddlebrook Div. II Retention/Detention Facility Type of Facility: Detention Pond Side Slope: 3.00 11:lV Pond Bottom Length: 71. 50 ft Pond Bottom Width: 71. 50 ft Pond Bottom Area: 5112. sq. ft Top Area at 1 ft. FB: 14496. sq. ft 0.333 acres Effective Storage Depth: 7.15 ft Stage O Elevution: 488.35 ft Storage Volu::ne: 62868. cu. ft 1.443 ac-ft Riser Head: Riser Diameter: Number of orifices: Ori.fice # 1 2 3 Height (ft) 0.00 4. 95 6.37 7.15 18.00 3 Diameter (in) 1.11 2.14 2.54 Top Notch Weir: None Outflow Rating Curve: None ft inches Full Head Discharge (CFS) 0.090 0.185 0.155 Pipe Diameter (in) 6.0 6.0 Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) 0.00 488.35 0. 0.01 488.36 51. 0.02 488.37 102. 0.03 488.38 151. 0.05 488.10 257. 0.06 4 88. 4 J. 308. 0.07 488.42 360. 0.08 488.43 412. 0.09 488.44 4 64. 0.10 488.45 516. 0.24 488.59 1252. 0.38 488.73 2005. 0.53 488.88 2832. 0.67 489.02 3621. 0.81 489.16 4 429. 0.95 489.30 5254. 1. 09 489.44 6097. 1. 23 489.58 6959. 1. 37 489.72 7839. 1. 51 489.86 8739. © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report (ac-ft) (cfs) (cfs) 0.000 0.000 0.00 0.001 0.004 0.00 0.002 0.005 0.00 0.004 0.006 0.00 0.006 0.007 0.00 0.007 0.008 0.00 0.008 0.009 0.00 0.009 0.010 0.00 0. 011 0.010 0.00 0.012 0. 011 0.00 0.029 0.017 0.00 0. 04 6 0.021 0.00 0.065 0.024 0.00 0.083 0.027 0.00 0.102 0.030 0.00 0.121 0.033 0.00 0.140 0.035 0.00 0 .160 0.037 0.00 0.180 0.039 0.00 0.201 0.041 0.00 20 Surf Area (sq. ft) 5112. 5121. 5129. 5138. 5155. 5164. 5172. 5181. 5189. 5198. 5320. 5443. 557'1. 5703. 5831. 5959. 6090. 6222. 6355. 6490. Saddlebrook Div. II Renton, Washington l. 65 490.00 9657. 0.222 0.043 0.00 6626. 1. 79 4 90. 14 10594. 0.243 0.045 0.00 6763. 1. 93 490.28 11550. 0. 265 0.047 0.00 6902. 2.07 490.42 12526. 0.288 0.048 0.00 7042. 2.21 490.56 13522. 0.310 0.050 0.00 7184. 2.35 4 90. 7 0 14538. 0.334 0.052 0.00 7327. 2.49 490.84 l~:574. 0.358 0.053 0.00 74·11. 2.63 490.98 16630. 0.382 0.055 0.00 7617. 2.n 4 91. 12 17707. 0.406 0.056 0.00 77 65. 2.91 491.26 18804. 0.432 0.057 0.00 7913. 3.05 491.40 19973. 0.457 0.059 0.00 8064. 3.19 491.54 21062. 0.484 0.060 0.00 8215. 3.33 491.68 22223. 0.510 0.061 0.00 8368. 3.47 491.82 23405. 0.531 0.063 0.00 8523. 3.61 491.96 24609. 0.565 0.064 0.00 8678. 3.75 492.10 25835. 0.593 0.065 0.00 8 836. 3.89 492.74 27083. 0.622 0.066 0.00 8994. 4.03 4 92. 38 28354. 0.651 0.068 0.00 9154. 4. 17 4 92. 52 2964 7. 0.681 0.069 0.00 9316. 4.31 492.66 30962. 0.111 0.070 0.00 94 7 9. 4.45 4 92. 80 32301. 0.742 o. 071 0.00 9643. 4.59 192. 94 33662. 0. 773 0.072 0.00 9808. 4.73 493.08 35047. 0.805 0.073 0.00 9976. 4.87 493.22 36455. 0.837 0.074 0.00 10144. 4.95 493.30 37271. 0. 856 0. 0/5 0.00 10241. 4. 97 493.32 37476. 0. 860 0.076 0.00 10265. 4.99 493.34 37681. 0.865 0.080 0.00 10290. 5.02 493.37 37991. 0. 872 0.086 0.00 10326. 5.04 493.39 38197. 0. 877 0.094 0.00 1.0351. 5.06 493.41 38405. 0.882 0.105 0.00 10375. 5.08 4 93. 4 3 38612. 0.886 0.117 0.00 10399. 5 .11 4 93. 4 6 389?,5. 0.894 0.125 0.00 10436. 5 .13 493.48 39134. 0.898 0.129 0.00 10461. 5. 27 493.62 40610. 0.932 0 .148 0.00 10633. 5.41 4 93. 7 6 42111. 0. 967 0.163 0.00 10807. 5.55 493. 90 43637. 1. 002 0.176 0.00 10983. 5.69 494.04 45186. l. 037 0.188 0.00 11159. 5.83 494.18 46761. 1. 073 0.198 0.00 11338. 5. 9'/ 4 94. 32 48 361. 1.110 0.208 0.00 11517. 6.11 49C46 49986. 1. 14 8 0.218 0.00 11698. 6. 25 4 94. 60 51637. 1.185 0.226 0.00 11881. 6.37 4 94. 72 53072. l. 718 0.234 0.00 12038. 6.40 494.75 53433. 1. 227 0.237 0.00 12078. 6.42 494.77 53675. 1.232 0.243 0.00 12104. 6.45 494.80 54039. 1. 241 0.253 0.00 12144. 6. 4 8 494.83 54c04. 1. 249 0.266 0.00 12183. 6.50 494.85 54 648. 1. 255 0.281 0. 00 12210. 6.53 491.88 55015. 1.263 0.300 0.00 12250. 6.56 494.91 55383. 1.271 0.320 0.00 12289. 6.58 4 94. 93 55629. 1.277 0.326 0.00 12316. 6.61 4 94. 96 5:,999. 1. 286 0.333 0.00 12356. 6.75 195.10 57742. 1. 326 0.362 0.00 12544. 6.89 495.24 59511. 1. 366 0.388 0.00 12732. 7.03 495.38 61307. 1. 4 07 0. 411 0.00 129n. © 2013 D. R. STRONG Consulting Engineers Inc. 21 Saddlebrook Div. II Technical Information Report Renton, Washington 7.15 495.50 62868. 1. 443 0.430 0.00 7.25 495.60 64183. 1. 473 0.906 0.00 7.35 495.'/0 65512. 1. 504 1. 760 0.00 7.45 495.80 66856. 1.535 2.870 0.00 7.55 495.90 68213. 1. 566 4.180 0.00 7. 65 4 96. 00 69584. 1. 597 5.660 0.00 7.75 496.10 70969. 1. 629 7.100 0.00 7.85 496.20 72369. 1.661 7.640 0.00 7.95 496.30 73782. 1.694 8.140 0.00 8.05 496.40 75210. 1. 727 8.620 0.00 8.15 496.50 76653. 1. 760 9.060 0.00 8.25 4 96. 60 78110. 1. 7 93 9. 4 90 0.00 8.35 496. 70 7 9581. 1. 827 9.900 0.00 8.45 496.80 81067. 1. 8 61 10.290 0.00 8.55 196. 90 82567. 1. 895 10.660 0.00 8. 65 4 97. 00 84083. 1. 930 11. 030 0.00 8.75 497.10 85613. 1. 965 11. 380 0.00 8.85 497.20 87158. 2.001 11.720 0.00 8.95 497.30 88718. 7.037 12.050 0.00 9.05 4 97. 10 90293. 2.073 12.370 0.00 Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 1. 89 0.43 7.15 495.50 2 0.92 0.35 6.69 495.04 3 1.11 0.22 6.16 494.51 4 0.92 0. 21 6.04 4 94 . 3 9 5 0. 97 0.15 5.32 4 93. 67 6 0.57 0.08 4. 95 493.30 7 0.73 0.07 1. 27 4 92. 62 8 0.76 0.06 3.02 491.37 Hyd R/D Facility Tributary Reservoir Outflow Inflow Inflow 1 0.43 0.06 ******** 2 0.35 0.03 ******** 3 0.22 0.03 **7'.·"A·*-J"** 4 0.21 0.03 *******·k 5 0.15 0.03 ******** 6 0.08 0.02 ******** 7 0.07 0. 0?. ******** 8 0.06 0.02 ·k·k*-k**** Route Time Series through Facility Inflow Time Series File:rdin.tsf Outflow Time Series File:rdout POC Time Series File:dsout Inflow/Outflow Analysis Peak Inflow Discharge: Peak Outflow Discharge: Peak Reservoir Stage: Peak Reservoir Elev: © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 1. 89 CFS 0.432 CFS 7.15 Ft 495.50 Ft 22 62870. 1.443 56962. 1.308 50523. 1.160 49188. 1.129 41150. 37295. 30617. 19659. ~oc Outflow Target Cale 0.45 0.44 *****"'* 0.36 * ·k -;..--is· ·k ·k ·/.: 0.23 ***·k·k** 0.22 ******* 0.16 ******* 0.08 ******* 0.08 -Jc!d< ·k * ·k * 0.08 at 6:00 on J'an at 11: 00 on Jan 0.945 0.856 0.703 0. 451 9 in 9 in 13087. 13224. 13363. 13502. 13642. 13782. 13923. 14065. 14208. 14 352. 14496. 14640. 14786. 14932. 15079. 15227. 15375. 15525. 15 67 4. 15825. Year 8 Year 8 Saddlebrook Div. II Renton, Washington Peak Reservoir Storage: 62870. Cu-Ft 1.443 Ac-Ft Add Time Series:bypass.tsf Peak Sumn1ed Discharge: 0.444 CFS at 11:00 on Jan 9 in Year 8 Point of Compliance File:dsout.tsf Flow Frequency Analysis Time Serles File:rdout.tsf Project Locat.ion:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.353 0.070 0 .221 0.059 0.07:, 0.153 0. 213 0.432 Computed Peaks 2 2/09/01 20:00 7 1/07/02 4:00 3 3/06/03 22:00 8 8/26/04 7:00 6 1/08/05 5:00 5 1/19/06 2:00 4 11/24/06 9:00 1 1/09/08 11:00 Flow Frequency Analysis Time Series File:dsout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.361 2 2/09/01 20:00 0.081 7 1/05/02 16:00 0.228 3 3/06/03 21:00 0. 077 8 8/26/04 2:00 0.083 6 1/0o/05 8:00 0.157 5 1/19/06 1:00 0.220 4 11/24/06 7:00 0.444 1 1/09/08 11: 00 Computed Peaks -----Flow Frequency Analysis------- --Peaks --Rank Return Prob (CFS) (ft) Period 0.432 7.15 1 100.00 0.990 0.353 6.70 2 25.00 0. 960 0. 221 6.16 3 10.00 0.900 0. 213 6.04 4 5.00 O. 800 0.153 5.32 5 3.00 0.667 0.075 4.95 6 2.00 0.500 0.070 4. 27 7 1. 30 0. 231 0.059 3.02 8 1.10 0.091 0.405 7.00 50.00 0. 98 0 -----Flow Frequency Analysis------- --Peaks (CFS) 0.444 0.361 0.228 0.220 0.157 0.083 0.081 0. 077 0.416 Rank 1 2 3 4 5 6 7 8 Return Prob Period 100.00 0.990 25.00 0. 960 10.00 0.900 5.00 0.800 3.00 0.667 7.00 0.500 1. 30 0.231 1.10 0.091 50.00 0.980 Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF CFS % % O.C05 33549 54.711 54.711 0.015 6223 10.148 64.860 0.025 5918 9. 651 74.511 0.035 4748 7.743 82.254 0.045 4536 7.397 89.651 0.055 2455 4.004 93.655 0.064 2006 3.n1 96. 92 6 0.074 1439 2.347 99.273 0.084 110 0.179 99.452 0.094 23 0.038 99.490 0.104 14 0.023 99.512 0.114 11 0.018 99.530 © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report Exceedence % 45.289 35.140 25.489 17.746 10. 34 9 6.345 3.074 0. 727 0.548 0.510 0.488 0.470 23 Probability 0.453E+OO 0.351E+OO 0.255E+OO O. l 77E+OO 0.103E+OO 0.635E-01 0.307E-Ol 0. '/?)E-02 0.548E-02 0.510E-02 0. 488E-02 0.470E-02 Saddlebrook Div. II Renton, Washington 0.124 26 0.042 99.573 0.427 0.427E-02 0.134 29 0.047 99.620 0.380 0.380E-02 0.144 38 0.062 99.682 0.318 0. 318E-02 0.154 35 0.057 99.739 0.261 0.261E-02 0.163 19 0.031 99. 770 0.230 0.230E-02 0.173 25 0.041 99. 811 0.189 0.189E-02 0.183 16 0.026 99.837 0.163 0.163E-02 0 .193 15 0.024 99.861 0.139 0 .139E-02 0.203 18 0.029 99. 8 91 0.109 0.109E-02 0. 213 19 0.031 99.922 0.078 0.783E-03 0.223 19 0.031 99.9S3 0.047 0. 4 73E-03 0.233 14 0.023 99.976 0.024 0.245E-03 0.243 2 0.003 99.979 0.021 0.212E-03 0.253 2 0.003 99.982 0.018 0.179E-03 0.263 1 0.002 99.984 0.016 0.163E-03 0 .272 0 0.000 99.984 0.016 0.163E-03 0.282 1 0.002 99.985 0.015 0.147E-03 0.292 0 0.000 99.985 0.015 0.147E-03 0.302 1 0.002 99.987 0.013 0 .130E-03 0.312 1 0.002 99.989 0. 011 0 .114E-03 0.322 0 0.000 99.989 0. 011 0 .114E-03 0.332 2 0.003 99.992 0.008 0.815E-04 0.342 1 0.002 99.993 0.007 0.652E-04 0.352 3 0.005 99.998 0.002 0.163E-04 Flow Duration from Time Series File:dsout.tsf Cutoff Count Frequency CDF Exceede!lce Probability CFS % % % 0.005 33512 54.651 54.651 45.349 0.453E+00 0.015 6220 10.144 64.795 35.205 O.J52E+OO 0.025 5951 9.705 74.499 25.501 0.255E+OO 0.036 4709 7. 679 82.179 17. 821 0.178E+OO 0. 04 6 4486 7.316 8 9. 4 94 10.506 0.105E+OO 0.056 25'/8 4.204 93.699 6.301 0.630E-01 0.066 1922 3.134 96. 833 3 .167 0.317E-01 0.076 1411 2.301 99.134 0.866 0.866E-02 0.086 175 0.285 99.119 0.581 0.581E-02 0. 096 36 O.OS9 99.418 O.S?2 0. 522F.-02 0.106 22 0.036 99.514 0.486 0.486E-02 0 .117 11 0.018 99.532 0. 4 68 0. 4 68E-02 0.127 25 0.041. 99.573 0.427 0.427E-02 0.137 26 0.042 99.615 0.385 0.385£-02 0.147 34 0.055 99.671 0.329 0.3292:-02 0.157 43 0.070 99.741 0.259 0.259E-02 0.167 19 0.031 99. 772 0.228 0.228E-02 0.177 24 0.039 99. 811 0.189 0.189E-02 0.188 16 0.026 99.837 0.163 0 .163E-02 0.198 15 0.024 99.861 0.139 0.139E-02 0.208 18 0.029 99.891 0 .109 0.109E-02 0.218 18 0.029 99.920 0.080 0.799E-03 0.228 18 0.029 99.949 0.051 O.S06E-03 0.238 14 0.023 99. 972 0.028 0.277E-03 0.248 3 0.005 99.977 0.023 0.228E-03 0.258 2 0.003 99.980 0.020 0.196E-03 © 2013 D.R. STRONG Consulting Engineers Inc. 24 Saddlebrook Div. II Technical Information Report Renton, Washington 0.269 ? 0.003 99.984 0.016 0.163E-03 o.n9 0 0.000 99.984 0.016 0.163E-03 0.289 1 0.002 99.985 0.015 0.147E-03 0.299 0 0.000 99.985 0.015 0.147E-03 0.309 0 0.000 99.985 0.015 0 .14 7E-03 0.319 2 0.003 99.989 0. 011 O.lHE-03 0.329 0 0.000 99.989 0. 011 0. ll.4F.-03 0.340 1 0.002 99.990 0.010 0.978E-04 0.350 3 0.005 99.995 0.005 0.489E-04 0.360 1 0.002 99.997 0.003 0.326E-04 Duration Comparison Anaylsis Base File: predev.tsf New File: dsout. tsf Cutoff Units: Discharge in CFS -----Fraction of Time--------------Check of Cutoff Base ::-::'ew %Change Probability Base 0. 077 0.95E-02 0.81E-02 -14.6 I 0.95E-02 0.077 0.098 0.63E-02 0.52E-02 -18.3 I 0.63E-02 0.098 0 .119 0.50E-02 0.46E-02 -6.3 I 0.50E-02 0.119 0.140 0.37E-02 0.37E-02 -0.1 I 0.37E-02 0.140 0.161 0.29E-02 0.25E-02 -14.2 I 0.29E-02 0.161 0.182 0.22E-02 0.18E-02 -17. 8 I 0.22E-02 0.182 0.203 O.lSE-02 0.13E-02 -13. 3 I O.lSE-02 0.203 0.224 O.lOE-02 0.65E-03 -36.5 I O.lOE-02 0.224 0.245 0. 62E-03 0.23E-03 -63.2 I 0.62E-03 0.245 0.266 0.34E-03 0.lSE-03 -47.6 I 0.34E-03 0.266 0.287 0. 21E-03 0.15E-03 -30.8 0.21.E-03 0.287 0.308 0.16E-03 0.15E-03 -10.0 0.16E-03 0.308 0.328 0.98E-04 0.111::-03 16. 7 0.98E-04 0.328 0. 34 9 0.16E-04 0.49E-04 200.0 0.16E-04 0.319 Maximum positive excursio~ = 0.022 cfs 6.4%) occurring at 0.338 c=s on the Base Data:predev.tsf and at 0.360 cfs on the New Data:dsout.tsf Maximum negative excursion= 0.020 cfs (-18.4%) occurring at 0.107 cfs on the Base Data:predev.tsf and at o.oa·, cfs on the New Data:dsout.tsf © 2013 D. R. STRONG Consulting Engineers lnc. Technical Information Report 25 Tolerance------- New 0.075 0.082 0.104 0.139 0.154 0.169 0.194 0. 211 0.225 0.235 0.251 0.285 0.340 0.361 %Change -1. 8 -15.8 -12.7 -0.2 -4.2 -6.9 -4.0 -5.6 -8.0 -11. 4 -12.2 -7.5 3.4 3.2 Saddlebrook Div. II Renton, Washington Peaks Plot , rdoul pks in Sea-Tac • -dsoutpks ' µredev p!cs 10-1_ • in "-0 \!, • e' ro ~ ~ - 5 10·2 : - - " - - 10·3 1 2 5 10 20 Duration Curve .. 0 000 ;;+----------- 00 © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report " • 0 30 Return P~riod 2 5 R 000 0 --v-• 0 • ! 00 ---~~---- 40 50 60 70 80 Cumulative Probability Pmbabilil Exceedence 26 10 ' • 90 20 ----'- 95 50 100 Q 98 99 rdout dur <> dsout.dur • 1arget dur c Saddlebrook Div. II Renton, Washington FLOW CONTROL PRIMARY OVERFLOW Using standard orifice equation to determine stand pipe diameter in control structure Ref. KCSWDM '09 Figure 5.3.4.H 0 100 = 100-Year Peak Storm calculated using KCRTS 15-Minute Time Steps 0100 = 4.65 cfs HMAX = Maximum available head in feet measured from crest of weir 0.75 ft. D = Riser Diameter D = (0100 / (3.782 * HMAX0'5))05 D = 1.19 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 0 100 H = (0100 I (9. 739 * D))'0.67 H = 0.47 ft. JAILHOUSE SECONDARY OVERFLOW Using standard weir equation to determine length of window opening in control structure Ref. KCSWDM '09 Figure 5.3.4.E D= Control structure diameter D= 60 in. 0 100= 100-Year Peak Storm calculated using KCRTS 15-Minute Time Steps 0100= 4.65 cfs HMAX= Head above weir achieved with 0 100 HMAX= 0.47 ft. P= Height of overflow above outlet invert elevation P= 7.15 ft. c= Constant c= 3.27+0.4*HMAxiP C= 3.30 ft. L= Arc length of the jailhouse window as necessary but not to exceed 50% of the control structure's internal circumference L= (0100 /(c*HMAx 1 ·51 )+0.2*HMAx L= 4.47 ft. (min. length) C= Control Structure Circumference C= 16 ft. Calculate corrected L due to vertical bars in window. Laai= adjusted arc length of the jail-house window Laai= L +0.083*(L/0.33) Laaj= 5.60 ft. © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 27 Saddlebrook Div. II Renton, Washington BIRDCAGE EMERGENCY OVERFLOW SPILLWAY Using sharp crested weir equation to determine stand pipe diameter in control structure Ref. KCSWDM '09 Figure 5.3.4.E 0 100 = 100-Year Peak Storm calculated using KCRTS 15-Minute Time Steps 0100= 4.65 els P= Height of primary overflow above outlet invert elevation P= 7.62 ft. D= Control structure diameter D= 60 in. L= Control structure circumference L= 15.71 ft. C= 3.27+0.4H/P (ft) use .. 0100= 3.27+0.4H/P(L-0.2H)HA1 .5 H= Emergency overflow water surface elevation H= 0.20 ft. WATER QUALITY TREATMENT (PART E) The Project is located in the Basic Water Quality (WQ) Treatment area. The Project will utilize a BayFilter vault meeting Basic Water Quality treatment criteria. See Figure 7 for details. © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 28 Saddlebrook Div. II Renton, Washington FIGURE 7. DETENTION FACILITY DETAILS AND BAYFILTER SIZING © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 29 Saddlebrook Div. II Renton, Washington I I I I I I I I I I I I I I I s ;,; ' ~ I I ~ ' 1 ! ' j '.> ~ I f , I 1 8 ~ "" 0 0 a: co w _J 0 0 ..,: (fJ 18 SE 1/4 SE OF SECTION 32, TOWNSHIP 23N, RANGE 5£, W.M. ,- SADDLE BROOK I ,. 4• INLH OR!F!Cf /8" INLH RUfJBfR '"" SOUD TOI' fOM ~ 4!15-00 rouna 0RlflC£ LsL Mf"IR W)LL Al SOI.ID TOP R!M~ 196.00 M'.i.R CREST -4/lB 27 12" OUTLH PIPC IN\l[RT -485 S7 f" OU TLfT PIP£ /N',f;RT -485.97 PLAN VIEW $}C;Q1pN A_A_ 18" l~'L[T P1PE /N\l[flj -488.27 4" OR/FIC[ TO Fil Tf:RS !N'.lfRT - 486.47 NOT£: INLET A~'D OUTI.H PIPE NOT 51/0~i.J FDR CLARITY OUTLE:T IN\/. [LEY 485 ~7 SECTION 8 B 78" Mli P!IH!M!NARY SIZING SUMMARY BAYFII ffR STC.~UWAllR fflr:AW{NT SYST[M ~::.;, ~;ORJ!WA-~R U~~AC£i,!£NT SYSTEM IS Al STOR.1/WATE'I FILTRATION onia: OES!CNW ro f/£1.JO\lc . fJNt· SWIMWJS, HEAVY MUALS, AND PHOS.~HORUS. t----------~-----------j TIIF fl A Ynl T[R SYST[!J !IH/£5 ON A SPIRAL WOUNO PROJtCf SACDLEBROO><: M[DIA Fn.TF:R CA.RTR1Q(;€ ~TH APPROXl((ATE:cY 4J t--------------j------------j SOOAR[ {[fr CF {/[ TRA non .'.R[A.. TH[ Fil TER LOCAi/ON RfNTON, WA CARfmOGfS MIC HOUSED IN A CONC,RH[ STRUCTUP[ t-------------j------------j THAT EVfNlY 01STRIBUT£S THE FLOW BfTM'.[N WAl!"R DUALITY now 0.ClS CFS CAF0Rl[)0£S. Tr/£ SYSlfM IS Off/.lN[ ','/ITH AN CKirnWL BYPASS TH.'<T R0Ur£S HIGI-! /llr£11S!TY DRA!NAG{ AR{A 5.397 AC. STOIWS A/IOU/ID iHE SYSTEM TH£ Fil TER CARTRIDGES CARTRIDG[ D{S/GN now RA!£ 3D GF'M i!~f;,r.,;~;~;:i::J:T)OM_,,:%~°tJC::n~~-TRAflON , f!A'ffllTfR CARTRIDGES 2 (8AS£fJ ON MASS WADING) ADS BA YFILTER DETAILS, PER ADVANCED DRAINAGE SYSTEMS, INC. ROCKERY /,IAX/MlJ/J HEIGHT 4-mr (TYP. 5££ DETAIL SHEU Cl~ 6' CHAINUIIK FE/IC£ Pt/I ~OT SID. PiA *RIP RAP PAD SPECIF/CATIONS RIPRAP SHAH 8[ R{ASONABlY J\HL CRADEO l\1JH GRADATION AS ff!LlOWSc MAXIMUM STOii£ s,z£: MtOiAN SfON{ SILE· M!llli./Ul.< S fON< $!7F: 2'1 INCHES (NO/ill/AL {!J}U[Tt.~) 16 !//CHES 4 INC/1£5 RIPRAP Sil/NG G0',/[/11/[D BY SID[ Sl0P[S ON mm.ET C.'fANNEL JS ASStJ!.'£D fO 8£ APPROX/MA TEL Y 3. I ___.B @ NORTH GRAPHIC SCALE L-~~.'~: :i: :-el 15 30 4,5 SWING/NG StCnoosi D£TENnON POND PLAN VIEW _!.L__ Call 2 Worki'lg Days Before You Dig 1-800-424-5555 Utilffieo Undergrouid Locatior, Cenlar CID.t.IT.ND,OA,WA) L. 1 INCll ~ 30 FT. ~ !l DR STRONG [[ [O) [fQJ .~~~ ' ' • ---so. W£1R CREST - 488.27 SECTION A-A !HO R/W - ,oo '"' I Ci ..,· ..;; .. "'' s "1 L_ MOO "" "" / _'lQP_OF 6 • W/Of 8£RJ.J EJc._ 496.2~,,.------',...J ,oo - ' ~I SECTION 8-8 MOO OTY COI.IWOITS DATED JANUARY 10, 2013 V """' V Pl.AN OfANGE 1 "" Pl.AN OfANGE: 2 V REVISiQr,; " 6°° CHA/Ill.INK FENC[ ''ft ROCk[IIY MAXll.!UJ.I 'HfJCHT 4~£r - _fX. CRA0£ _______ _ I 6" C/'iNNUNK FE~·IT I_ ,---~ -. ------------------------------"""' ·1·""'''"00 "'" ;"-., 7.15" W£ SrDRAG£ _J"_;, IO 5 SED!l.l[NT STOF/AC[ --1 - PDJ,,D 801TOU [L!VATiON 4878~--------'--------------TOP OF SEO!l.<[N!.._~!2ft.G.£.£l_!_8,!!~---- ,- ' ~1 s[ ij ~! 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PLAN -201.00 MARCH 2~0B e PllBL'.I: Wil:lXS ::Jl:?ARTMENT CATCH BASIN INSTALLATION STD. PU..'< -202.DD J.IARC:i 2003 PRO\ADE l,U1NTfNANC[ ACCESS BY ltf:LDING 'I CROSS9ARS !Q -4 vfRTICAL BARS AS SHOWN. HU/G[ UPPER ENDS ~TH F!.ANGES/ BO/. TS ANO PR0\1/0E LOCK/NG J./ECHANJSJ./ (PAOWCK} CN WWfR END. "'""' ·,e,as" W/ '°"'"' eo, ,S~- ____ Rf'}_~ )-49WO __l '1£W LOO. If S1£PS OIRECTl Y BELOW ' SI.IOOT/1 1-f"RnCAl 8A LOlt£R 51£H BAND,;" X 4" ~DE fDRJ.JFD m nr IN GROvf OF C.8. RiSf:fl 2-<" SEE NOTE I UPPFR ST([[ BAND 1° X 1· \\WE --,M CB R1eER :I" D!A. SMOOTH RDWID BARS wnorn £DUA!!. Y 5PAC£0 BARS SHAH 8[ 'M:lOEO TO UPPER Ji WW[R SANDS (24 BAI/OS EVfNLY SPACEO SIT NOTE 1) ,/) FUD'G&CY O\UO ON £ WS FffV--4.~6.17 w TOf OF r,.i[RG(N[r S1 ovrnncw~49597 "" STANDARD CA(VAN!ZEO STEPS DR UDD<R ~ ,~um SECTION A-A HOOK CLAMP ANCHO'<EO 70 CB RISER DETAIL HOOK CLAMP ~ ,. 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PUN -203.00 l!lt:lCP. 2008 CIRCUMFERENCE lfl/CTH r-~--~~oOP:/1:i.t::.£05.~?f ulll1ilf71 '"'°'" ' w,, S5 97 FRAME/GRAT[ FOR SECONDARY IN.ET. Pi/OVIOE ',fR/ICAL BARS IN FRAU[ 0 4 O.C. (OTHER FLOW SYSTEMS ACCEPTABif If APPROVfD IIY ODES} SE£ A(SO THE $£PARA 7£ OV[RflOW S!RUCT'JRE SHOI\I\/ IN FIGURE 5 J.1.C JAILHOUSE H1NDOW DETAIL R£MOV.A5ff WA a[llr!GJIT COUPLl!IIJ OR Fl.ANG£ I::)· I MM Pl A!£ WE"L0£D TO ELBOW 111TH OR!hCE AS SPEC1F1£0 :...I_~ , I, _]' ELBOW RESTRJCTOR DETAIL Of Cal 2 Working D.o.~s Before You Dia 1-800-424-5555 [[ [) ~~·11 dstfr!tJ/;s:t.~ERS I : 1=~ .. , 1,., 1~,.,~ ~ r-s ENGINEfiRS P!.,WNERS SUR\,9'Q;'S • PL..\N CHANGE 2 "<> ru. ~"' • ., •. , .,..... ~ n 1°1.2e.1JI MAJ 1 ·-.. ···SJs ;-;::, ~ '~~' 1 .. I >S NOTED I ,.,~'/',\'.,~,%"'U't'«,,, 11 "~"·:m I I ~ ;R RC:N TON SADDLEBROOK STORM DRAINAGE DETAILS l/t!ltie8 UnderlJl'"O<nd Loca~on Center (D,MT.ND,Ofl.WA) IOIIIUNE.»thPl.l!D1}(JRJ(U,NU,~96033' 0"25.IJU.9063 Fa:5.127.3123 --~alffl ·- NO. I REVIS;ON "' ,- = Plc,nn1ng/Buildinq/Pc1~lic \h'c,rks De;.,! "'"-<"-==• = N>S "" 11-14-12 C14 1-4 =,1 A[-[N[N[N[N[A[A ADS Representative: Date: ISite Information Proiect Name Citv State Drainaee Area lmoervious Area Pervious Area % lmoervious I Upstream Detention System Peak release rate from detention Treatment release rate from detention System Configuration Detention pretreatment credit IWA DOE Approval BayFilter Sizing Details Saddlebrook Seattle WA 5.397 2.857 2.54 53% 0.432 0.o75 Offline 60% I General Use Desi,nation I Ives 11-'A=eie~n~cv~,e~,a~u-ir~e~d~%~, ~,e~m~a~v-a-1---------tl 180% I Filter System Filtration Brand BayFilter CartridRe Hei,ht 28 Cartridge Filter Area 43 Maximum Cartridge Flow Rate 0.7 Specific Flow Rate 30 Determine Critical Sizing Value Number of Cartrid es Usin Flow Rate 2 !SUMMARY Treatment Flow Rate 0.075 Cartride:e Flow Rate 30 Number of Cartridges 2 acres acres acres cfs cfs i n sf gpm/sf gpm cfs gpm SECTIONV CONVEYANCE SYSTEM ANALYSIS AND DESIGN Per Core Requirement #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 was used to calculate the Q-Ratio for each pipe node. A conveyance system consisting primarily of pipes and catch basins has been designed for Saddlebrook Div. I and Div. II. 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 0.87%. The pond 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 4.65 cfs. The results of the 15-minute KCRTS time series and KCBW Calculations are included in this Section. DEVELOPED 15-MINUTE TIME SERIES Modeling input Land cover Entire Site Till forest (ac) 0.000 Till Grass (ac) 2.540 Wetland (ac) 0.000 Impervious (ac) 2.857 Scale Factor: 1.00 Time Step: 15-Min Data Type: Reduced Project location: Seatac Total Area: 5.397 Table 5 Developed 15-Min KCRTS Modeling Input © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 30 Saddlebrook Div. II Renton, Washington Modeling results Developed 15-Min Flow Frequency Analysis Time Series File:15-min-sea.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 1. 36 6 8/27/01 18:00 1. 01 8 1/05/02 15:00 3.13 2 12/08/0? 17:15 1.10 7 8/23/04 14:30 1. 96 4 11/17 /04 5:00 1. 69 5 10/27/05 10:45 1. 93 3 10/25/06 22: 45 4.65 1 1/09/08 6:30 Computed Peaks © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report -----Flow Frequency --Peaks Rank (CFS) 4.65 1 3.13 2 1. 96 3 1. 93 4 1. 69 5 1. 36 6 1.10 7 1. 01 8 4.15 31 Analysis------- Return Period 100.00 25.00 10.00 5.00 3.00 2.00 l. 30 1.10 50.00 Prob 0.990 0. 960 0.900 0.800 0. 667 0.500 0.231 0. 091 0.980 Saddlebrook Div. II Renton, Washington BACKWATER ANALYSIS Storm Water Runoff Variables: A= Tota! of Subasin and Tributary Areas C= Runoff Coefficient {the anticipated proportion of rainfall volume that runs off the areal see 2009 KCSWM Table 3.2.1A CC= Composite Runoff Coefficient CC= S(Cn•An)IATotal Tc= Time of Concentration (Typically 6.3 minutes which is the minimum value used in calculations) R= design return frequency iR= Unit peak rainfall intensity factor iR= (aR)(Tc)A(-bR) aR,bR= coefficients from '09 KCSWM Table 3.2.1.B used to adjust the equation for the desi_g_n storm lR= Peak rainfall intensity factor for a storm of return frequency 'R' IR= PWiR PR= total precipitation (inches) for the 24-hour storm event for the given frequency. See lssopluvial Maps in 2009 KCSWM Figures 3.2.1.A w D OR= peak flow (cfs) for a storm of return frequency 'R' QR= CC*iR*A The O~Ratio describes the ratio of the tributary flow to the main upstream flow. R= iai'&oi -year storm aR= 2.61 bR= 0.63 PR= RIBJi inches Conveyance System Variables: d= pipe diameter n= Manning's Number I= length of pipe © 2013 D. R. STRONG Consulting Engineers lnc. Technical Information Report 32 Saddlebrook Div. II Renton, Washington Pipe Structures Subasins & A A Tributaries FROM CB To CB Sf Ac 4 4 3 4 589 0.01 IRU~ 103-3 3 39482 0.91 2 3 36336 0.83 3 3 2 3 75818 1.74 RUN 102-2 21239 0.49 2 2 1 2 30748 0.71 2 2 2 51987 1.19 RUN 101-1 1006 0.02 RUN 703-1 81331 1.87 INLET 1 1 5477 0.13 INLET 1 1 67814 2.02 703 703 702 703 36095 0.83 702 702 701 702 4210 0.10 701 701 7 701 4217 0.10 7 7 5 7 735 0.02 5 5 1 5 36074 0.83 81331 1.87 101 101 1 101 1006 0.02 102 102 2 102 21239 0.49 103 103 3 103 39482 0.91 © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report C cc Tc ;a IR QR SQR Q- subasin Ratio Ac Min. ct, els CB#4 TO INLET 1 0.90 6.3 0.82 3.27 O.D4 0.04 0.00 0.63 I 0.61 0.62 6.3 0.82 3.27 3.54 3.58 88.91 0.58 0.57 0.58 6.3 0.82 3.27 2.25 5.83 0.63 0.90 0.59 0.90 0.61 6.3 0.82 3.27 4.06 9.89 0.70 CB#703 TO CB#1 0.51 6.3 0.82 3.27 1.36 1.38 0.00 0.90 6.3 0.82 3.27 0.28 1.66 0.21 0.90 6.3 0.82 3.27 0.29 1.95 0.17 0.90 6.3 0.82 3.27 0.05 2.00 0.03 0.60 6.3 0.82 3.27 1.62 3.62 0.81 0.59 CB#101 TO CB#1 0.90 6.3 0.82 3.27 0.07 0.07 0.00 CB#102 TO CB#2 0.58 6.3 0.82 3.27 0.93 0.93 0.00 CB#103 TO CB#3 0.63 6.3 0.82 3.27 1.88 1.88 0.00 33 d Material n I Slope invert invert in °"' in ft % ft ft 12 N-12 0.012 36 1.46 498.50 497.98 12 N-12 0.012 222 0.87 497.98 496.05 18 N-12 0.012 299 1.10 495.55 492.27 18 N-12 0.012 63 6.25 492.27 488.35 12 N-12 0.012 77 3.88 502.61 499.63 12 N-12 0.012 122 3.51 499.63 495.35 12 N-12 0.012 23 1.00 495.35 495.12 12 N-12 0.012 31 2.28 495.12 494.42 12 N-12 0.012 25 6.73 494.42 492.77 12 N-12 0.012 21 0.98 492.98 492.77 12 N-12 0.012 24 20.05 500.93 496.05 12 N-12 0.012 24 0.99 498.22 497.98 over- flow elev. ft 501.50 501.22 505.93 499.73 507.61 502.63 498.50 498.12 499.42 497.86 505.93 501.22 Q V Bend Full Full Flow Flow ct, fps 4.68 5.95 0 3.61 4.60 0.2 11.95 6.76 0.2 28.52 16.14 124.59 7.62 9.70 0 7.25 9.23 88.23 3.87 4.92 18.74 5.54 7.44 44.11 10.04 12.78 57.44 3.83 4.88 0 17.33 22.06 o 3.84 4.89 0 Saddlebrook Div. II Renton, Washington CB Dia 2 2 4 4 2 2 2 2 2 2 2 2 BACKWATER ANALYSIS MAP © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 34 Saddlebrook Div. II Renton, Washington I I I I I I I I I I I I I I I I I I I ~ ~ '<( ~ !fl .... • II ' I L -, l I 32,622 S.F. L LOT 703 ~~~ II' r--t J--.. -----h -. J RO D 703 , _3. 3 5.. ---·~ ~+ -·· 1 r----..1.-1::. ____ r ___ .]1-----t-----r----l-----T------,.J I • ROAD 707 4,277 S.F. ~ JI ~ '<( LOT 5 30,538 S.F. LOT 102 18,801 S.F. ~ ~ ~ L _____ ------!fl ,_ . ROAD 5 .. ROAD 702 ] ROAD 7 ' .....,""""".-·~~-.• --. 1 5 536Sf~~-----··-·-.. ... . ~2,43!,~--- LOT 103 29,492 S.F. CE~ .. 1+-----~----j .. . L --"..~EOAQ 103Ll?1J ' ... ' .· ) 9JJgrrs:r. . -L . ~" . f ~ ~ '<( ~ S:: ~ 7 35 S. F. ROAD 1 ROAD 2 -,-~~-~-~--=-~nr~ ~-J43T°ST~ =-r ROAD 101 --.! 917 S.F. ~-~-3~:LYJ·~JL-~-~nJ,r--·-----.~=~ rt-----~-, . i j r1 i I I 1 i ) I(,) . I I( ~ ' G @ LOT 2 28,317 SF. LOT 3 29,539 S.F. ! ~ ~ '<( ~ Sc ~ @ NOR.TH GRAPHIC SCALE 0 30 60 1 INCH= 60 FT. 90 R: \2012\0\ 12010\3\Drawin~·s \Base\38#12010.dwg 5/3/2013 9: 55: 16 AM PDT COPYRIGHT @ ::'GI 2, DR. S'RONG CONSULT. \IG ENGlt\'::ERS INC. ~ '" !:\! <!l Ci (!) (!) is i1i ~~ 0: <: c; 8 ::::: s cS ~ 0 ffi Ll.j 6 Q ~ a.. :li !!.l ~ ..... ~ <( fli i-;: ~ (j ~ ~ i ! I ~ !t ti ~ ~ ~ ~ ~ I ~ ! ij ij a' ~ ~ ~ . ei ~ ~ ~ ~ C ~ I DRAFTW BY: YLP DESIGNED BY: YI.P PROJFCT FNG!NfER: MAJ DA TE: 04_.Ja 13 PROJECT NO.: 130.JO ORA WING: 1 SHffT: 1 OF 1 I BACKWATER ANALYSIS RESULTS BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:CB#4 TO INLET 1.bwp Surcharge condition at intermediate junctions Tailwaler Elevation:494.51 feet Discharge Range:0.985 to 9.89 Step of 0.985 [cfs] Overflow Elevation:501.5 feet Weir:NONE Upstream Velocity:O. feet/sec PIPE NO. 1: 62 LF -18"CP @ OVERFLOW-EL: 499.73 6.25% OUTLET: 488.35 INLET: 492.27 INTYP: 5 JUNC NO. 1: BEND: 90 DEG DIA/WIDTH: 4. 0 Q-RATIO: 0. 70 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN DO DE HWO HWI ******************************************************************************* 0.99 2. 2 6 494.53 * 0.012 0.38 0.20 6.16 6.16 2.25 2.26 0. 4 6 1. 97 2. 2 9 194.56 * 0.012 0.53 0.27 6.16 6.16 2.26 2. 2 9 0.69 2.95 2.36 494.63 * 0.012 0.66 0.33 6.16 6.16 2.28 2.36 0.89 3. 94 2. 45 4 94. 72 * 0.012 CJ. 7 6 0.38 6.16 6.16 2.32 2. 45 1. 08 1.93 2.57 494.84 * 0.012 0.86 0.43 6.16 6.16 2.36 2.57 1. 2 6 5. 91 2.72 4 94. 99 * 0.012 0.94 0.47 6.16 6.16 2.41 2.72 1.45 6.90 2.89 495.16 * 0.012 1. 02 0.51 6.16 6.16 2.47 2.89 1. 64 7.88 3. 09 495.36 * 0.012 l. 09 0.51 6.16 6.16 2.51 3.09 1. 83 8.87 3.31 195. 58 * 0.012 1.16 0.58 6.16 6.16 2. 62 3.31 2.06 9.85 3.56 4 95. 83 * 0.012 1.22 0.61 6.16 6.16 2. 71 3.56 2.32 10.84 3.84 496.11 * O.Oll 1.27 0. 65 6.16 6.16 2.81 3.84 2.61 PIPE NO. 2: 2 99 LF -18"CP @ 1.10% OUTLET: 492. 27 INLET: 495.55 INTYP: 5 JUNC NO. 2: OVERFLOlil-EL: 505.93 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.63 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ******************************************************************************* 0.58 0.37 495.92 * 0. OJ 2 0. 29 0.23 2.26 2.26 0. 2 9 ***** 0.37 1. 16 0.51 496.09 * 0.012 0.41 0.32 2. 2 9 2.29 0.41 ***·!;-}; 0.54 1. 74 0.66 496.21 * 0.012 0.50 0.39 2.36 2.36 0.50 ***** 0. 66 2.32 o.n 4 96. 32 * 0.012 0.58 0.45 2.45 2. 45 0.58 ***** 0.77 2.90 0.87 4 96. 42 * 0.012 0.65 0.51 2.57 2.57 0.65 ***** 0.87 3.49 0.95 496.50 * 0.012 0.72 0.56 2. 72 2.72 0.72 ***** 0.95 4.07 1. 03 496. 58 * 0.012 0.78 0.61 2.89 2.89 0.78 ***** 1. 03 4.65 1. 10 496. 65 * 0. 012 0.83 0.66 3.09 3.09 0.83 ***** 1. 10 5.23 1.1 7 496.72 * 0.012 0.89 0.70 3.31 3.31 0. 8 9 ·k·k*** l.U 5.81 1. 32 496.87 * 0.012 0.94 0. 74 3.56 3.56 1. 08 1. 32 1. 24 6.39 1. 53 497.08 * 0.012 0.98 0.79 3.84 3.84 1. 4 4 1. 53 1.30 PIPE NO. 3: 221 LF -12"CP @ 0.87% OUTLET: 4 96. 05 INLET: 497.98 INTYP: 5 JUNC NO. 3: OVERFLOW-EL: 501. 22 BEND: 0 DEG DIA/WIDTH: 2.0 Q-Rl\TIO: 88. 91 Q(CFS) HW(FT) HW ELEV. * N-FAC DC ON TW DO DE HWO HWI ******************************************************************************* 0.36 0.33 498.31 * 0.012 0.25 0.22 0.00 0.22 0.25 ***** 0.33 0. 71 0. 4 9 498.47 * 0.012 0.36 0.31 0.04 0.31 0.36 *·!d:** 0. 4 9 1.07 0.61 198.59 * 0.012 0.44 0.38 0.16 0.38 0.44 ***** 0.61 1. 43 0. 73 498.71 * 0.012 0.51 0.44 0. 2·1 0.44 0.51 ***** 0.73 1. "/8 0.85 498.83 * 0.012 0.57 0.50 0.37 0.50 0.57 ***** 0.85 2.14 o. 96 498.94 * 0.012 0.63 0.56 0.45 0.56 0.63 ***** 0. 96 2.50 1. 07 499.05 * 0.012 0.68 0.62 0.53 0.62 0.68 ****·k 1. O"/ 2.85 1.19 199.17 * 0.012 0.73 0.68 0.60 0.68 0.73 ***** l. 19 3.21 1. 33 499.31 * 0.012 0.77 0.74 0. 6"/ 0.74 o.n ***** 1. 33 3.57 1. 4 9 499.47 * 0.012 0.81 0.82 0.82 0.82 0.82 1. 4 4 1. 49 3.92 1. 97 499.95 * 0.012 0.85 1. 00 1. 03 1. 03 1. 39 1. 97 1. 66 © 2013 D.R. STRONG Consulting Engineers Inc. 35 Saddlebrook Div. II Technical Information Report Renton, Washington PIPE NO. 4: 35 LF -l2 11 CP @ 1.46% OUTLET: 197.98 INLET: 498.50 INTYP: 5 Q(CFS) HW(l'T) HW ELEV. * N-FAC DC DN ?W DO DE HWO HWI ******************************************************************************* 0.00 0.01 0.01 0. 02 0.02 0.02 0.03 0.03 0.04 0.04 0.01 0.04 0.06 0.10 0.22 0.33 0.45 0.56 0.68 0.82 0.97 1. 4 6 498.54 498.56 498.60 498.72 498.83 498.95 499.06 499.18 4 99. 32 499.47 499.96 * 0.012 * 0.012 * 0.012 * 0.012 * 0.012 * 0.012 * 0.012 * 0.012 * 0.012 * 0.012 ., 0.012 0.03 0.04 0.05 0.06 0.06 0.07 0.07 0.08 0.08 0.09 0.09 0.03 0.04 0.04 0.05 0.05 0.06 0.06 0.06 0.07 0. O"/ 0.07 BACKWATER COMPUTER PROGRAM FOR PIPES 0.33 0.49 0.61 0.73 0.85 0. 96 1. 07 1. 19 1. 33 1. 49 1. 9"/ Pipe data from file:CB#703 TO CB#l.bwp Surcharge condition at intermediate junctions Tailwater EJ.evation:495.84 feet 0.33 0.49 0.61 0.73 0.85 0. 96 1. O"/ 1.19 1. 33 1.49 1. 97 Discharge Range:l.38 to 3.62 Step of 0.224 [cfs] Overflow Elevation:507.61 feet Weir:NONE Upslream Velocity:0. f~ct/scc 0.03 0.05 0.10 0.22 0.33 0.45 0.56 0.68 0.82 0.97 1. 4 6 0.04 0.06 0.10 0.22 0.33 0.45 0.56 0.68 0.82 0.97 1. 46 0.03 0.04 0.05 0.06 0.07 0.08 0.08 0.09 0.10 0.10 0.11 PIPE NO. 1: 24 LF -12"CP @ OVERFLOW-EL: 499.42 6.73% OUTLET: 492.77 INLET: 494.42 INTYP: 5 JUNC NO. 1: BEND: 57 DEG DIA/WIDTH: 2.0 Q-Rl\TIO: 0.81 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ******************************************************************************* 1. 38 1. 60 1. 83 2.05 2.28 2.50 2.72 2.95 3.17 3.10 3. 62 1. 53 1. 56 1. 60 1. 65 1. 70 1. 7 6 1. 83 1. 90 1. 97 2.05 2.14 495.95 495.98 496.02 496.07 496.12 496.18 496. 2:) 496. 32 4 96. 39 496.47 4 96. 56 * 0.012 * 0.012 * 0.012 * 0.012 * 0. OJ? * 0.012 * 0.012 * 0.012 * 0.012 * 0.012 ' 0.012 0.50 0.54 0.58 0. 62 0. 65 0.68 0. 71 0.74 0.77 0.79 0.82 0.26 0 . ?. 8 0. 2 9 0.31 0.33 0.35 0.36 0.38 0.39 0. 41 0.42 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 3.07 1. 4 6 1. 4 6 1. 47 1. 4 9 1. 51 1. ~2 1. 54 1. 56 1. 59 l. 61 1. 64 1. 53 1. 56 1. 60 1. 65 1. 70 1. 7 6 1. 83 1. 90 1.97 2.05 2 .14 0.69 0.76 0.83 0.91 0. 98 1. 05 1.12 1. 20 1. 2 9 1. 39 1. 4 9 PIPE NO. 2: 30 LF -12''CP @ OVERF!,OW-EL: 4 98 .12 2.28% OUTLET: 494.42 INLET: 495.12 INTYP: 5 JUNC NO. 2: BEND: 44 D~G DIA/WlD'l'H: 2.0 Q-RATIO: 0.03 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ******************************************************************************* 0. 7 6 0.89 1. 01 1.13 1. 26 1.38 1. 50 1. 63 1.75 1. 88 2.00 0.87 0.90 0. 96 1. 01 1. 08 1.15 1.23 1. 31 1. 41 1.51 1. 61 495.99 4 96. 02 496.08 196 .13 4 96. 20 4 96. 27 4 96. 35 496.43 4 96. 53 496. 63 496. 73 ' 0.012 * 0.012 ' 0.012 * 0.012 * 0.012 * 0.012 * 0.012 * 0.012 * 0.012 * 0.01?. * 0.012 © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 0.37 0.40 0.43 0.45 0. 4 8 0.50 0.53 0.55 0.57 0.59 0.61 36 0.25 0.27 0.29 0.30 0.32 0.34 0.35 0.37 0.38 0.40 0. 41 1. 53 1. 56 1. 60 1. 65 1. 70 1. 76 1. 83 1.90 1. 97 2.05 ?. .14 l. 53 1. 56 1.60 1. 65 1. ·10 1. 7 6 1. 83 1. 90 1. 97 2. 05 2 .14 0.85 0.88 0.93 0.98 1. 04 1.10 1.17 1. 25 1. 33 1. 42 1. 52 0.87 0.90 0. 96 1. 01 1. 08 1.15 1. 23 1. 31 1.11 1. 51 1. 61 0.49 0.53 0.57 0.61 0.65 0.68 0. 72 0.75 0.79 0.82 0.85 Saddlebrook Div. II Renton, Washington PIPE NO. 3: 23 LF -12"CP @ 1. 00% OUTLET: 4 95. J 2 INLET: 495.35 INTYP: 5 JUNC NO. 3: OVERFLOW-EL: 498.50 BEND: 18 DEG DIA/WIDTH: 2.0 Q-RATIO: 0 .17 Q(CFS) HW(FT) HW ELEV. * N-FAC DC ON TW DO DE HWO HWI ******************************************************************************* 0.74 0.68 496. 03 * 0.012 0.37 0.30 0.87 0.87 0. 64 0.68 0. 4 9 0.86 0.72 4 96. 07 * 0.012 0.39 0.33 0.90 0.90 0.68 0. 72 0.53 0.98 0.78 496.13 * 0.012 0.42 0.35 0. 96 0. 96 0.73 0.78 0.57 1.11 0.84 496.19 * 0.012 0.45 0.37 1. 01 1. 01 0.79 0.84 0.61 1.23 0. 92 496.27 * 0.012 0.47 0.39 1. 08 1. 08 0.87 0.92 0.65 1. 35 0.99 496.34 * 0.012 0.50 0.41 1.15 1. 15 0.94 0.99 0.68 1. 4 7 1. 08 4 96. 43 * 0.012 0.52 0.43 l. 23 1. 23 1. 03 1. 08 0.72 1.59 1. 18 4 96. 53 * 0.012 0.54 0.45 1. 31 1. 31 1.12 1.18 0.75 1. 71 1. 29 496.64 * 0.012 0.56 0.47 1. 41 1. 41 1.22 1. 29 0. 78 1. 83 1. 41 496.76 ., 0.012 0.58 0.49 1. 51 1. 51 1. 33 1. 41 0.81 1. 95 1. 53 496.88 * 0.012 0.60 0.51 1. 61 1.61 1. 44 1.53 0.85 PIPE, NO. 4: 121 LF -12"CP @ 3.51% OUTLET: 495.35 INLET: 499.63 INTYP: 5 JUNC NO. 4: OVERFLOW-EL: 502.63 BEND: 88 DEG DIA/WID'n: 2.0 Q-RATIO: 0.21 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ******************************************************************************* 0.63 0.44 500.0/ * 0.012 0.31 0.21 0.68 0.68 0.34 ***** 0.44 0.74 0. 4 9 500.12 * 0.012 0.36 0.22 0.72 0. 72 0.36 ***** 0.49 0.84 0.53 500.16 * 0.012 0.39 0.24 0.78 0.78 0.39 ***** 0.53 0.94 0.56 500.19 * 0.012 0.41 0.25 0.84 0.84 0. 41 ***** 0.56 1. 05 0.60 500.23 * 0.012 0.44 0. 2 6 0. 92 0. 92 0.44 ***** 0.60 1.15 0.64 500. 27 * 0.012 0. 4 6 0.27 0.99 0.99 0. 4 6 ***** 0. 64 1. 25 0.67 500.30 * 0.012 0.48 0.29 1. 08 1. 08 0.48 ***** 0.67 1. 36 0.71 500.34 * 0.012 0.50 0.30 1.18 1.18 0.50 ***** 0.71 1. 4 6 0.75 500.38 * 0.012 0.52 0.31 1.29 1. 2 9 0.52 ***** 0.75 1. 56 0. 78 500.41 * 0.012 0.54 0.32 l. 4 l 1. 41 0.54 ***** 0.78 1.66 0.82 500.45 * 0.012 0.55 0.33 1. 53 1. 53 0.55 ***** 0.82 PIPE NO. 5: 76 LF -12"CP @ 3.88% OUTLET: 499.63 INLET: 502.61 INTYP: 5 Q(CFS) HW(FT) IIW ELEV. * N-FAC DC DN TW DO DE HWO HWI ******************************************************************************* 0.53 0. 4 0 503.01 * 0.012 0.61 0.43 503.04 * 0.012 0.70 0.46 503.07 * 0.012 0. /8 0.50 503. 11 * 0.012 0.87 0.53 503.14 * 0.012 0.95 0.56 503.l"/ * 0.012 1. 04 0.59 503.7-0 * 0.012 1. 12 0.62 503.23 * 0.012 1.21 0.65 503.26 * 0.012 1. 2 9 0.68 503.29 * 0.012 1. 38 0.70 503.31 * 0.012 © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 0.31 0.33 0.35 0.37 0. 4 0 0. 41 0.43 0.45 0.47 0.49 0. 50 37 0.18 0.44 0.44 0.20 0.19 0.49 0.21 0.53 0.53 0.22 0.56 0.56 0.23 0.60 0.60 0.24 0. 64 0.64 0.25 0.67 0.67 0. 2 6 0.71 0. 71 0.27 0.75 0.75 0.28 0.78 0. '/8 0.29 0.82 0.82 0.31 0.33 0.35 0.37 0.40 0.41 0.43 0.45 0.47 0. 4 9 0.50 ****·k 0.40 ***** 0.43 ***** 0.46 ***** 0.50 ·k**** 0.53 ***** 0.56 ***** 0.59 ***** 0. 62 ***** 0.65 ***** 0.68 ***** 0.70 Sadd!ebrook Div. II Renton, Washington BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:CB#lOl TO CB#l.bwp Surcharge condition at intermediate junctions Tailwater Elevation:495.84 feet Discharge Range:0.07 to 0.07 Step of 0.07 [cfs] Overflow Elevation:497.86 feet Weir:NONE Upstream Velocity:O. feet/sec PIPE NO. 1: 21 LF -12"CP @ 0.98% OUTLET: 492.7'1 INLET: 492.98 INTYP: 5 Q(CFS) HW(FT) HW ELEV. ·k N-Fl\.C DC DN TW DO DE HWO HWI ******************************************************************************* 0.07 2. 87 495.85 * 0.012 0.11 0.10 3.07 3.07 2.87 BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:CB#102 TO CB#2.bwp Surcharge condition at intermediate junctions Tailwater Elevation:496.87 feet Di_scharge Range: 0. 93 to O. 93 Step of O. 93 [cfs I Overflow Elevation:505.93 feet Weir;NONE Upstream Velocity:O. feet/sec 2.87 0 .14 PIPE NO. 1: 24 LF -12"CP @ 20.05% OUTLET: 496.05 INLE~: 500.93 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC ON TW DO DE HWO HWI ******************************************************************************* 0.93 0.47 501.40 * 0.012 0.41 0.16 0.82 0.82 0.41 ***** 0.47 BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:CB#103 TO CB#3.bwp Surcharge condition at intermediate j~nctions Tailwater Elevation:499.47 feet Discharge Range:1.88 to 1.88 Step of 1.88 [cfs] Overflow Elevation:501.22 feet Weir:NONE Upstream Velocity:0. feet/sec PIPE NO. 1: 24 LF -12"CP @ 0.99% OUTLET: 497.98 INLET: 498.22 INTYP: 5 Q(CFS) HW(F7) HW ELEV. * N-FAC DC ON TW DO DE HWO HWI ******************************************************************************* 1. 88 1. 4 4 499.66 * 0.012 0.59 0.50 1.49 1.49 1.31 © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 38 l. 44 0.88 Saddlebrook Div. 11 Renton, Washington SECTION VI SPECIAL REPORTS AND STUDIES The following report and studies have been provided with this submittal. 1. Geotechnical Engineering Study -Earth Solutions NW, LLC, August 21, 2012 2. Geotechnical Consult Saddlebrook Phase II -Earth Solutions NW, LLC, May 15, 2013 3. Tree Inspection Report-Greenforest, Inc., May 1, 2013 © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 39 Saddlebrook Div. II Renton, Washington SECTION VII OTHER PERMITS, VARIANCES AND ADJUSTMENTS Approved Drainage Adjustment 2012-03 (Attached) Approved ADS BayFilter Adjustment 2012-04 (Attached) © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 40 Saddlebrook Div. II Renton, Washington PUBLIC WORKS DEPARTMENT MEMORANDUM DATE: August 16, 2012 TO: Arneta Henninger, Plan Reviewer J ' FROM: {)2~-Ron Straka, Surface Water Utility Supervisor, x7248 STAFF CONTACT: Hebe Bernardo, Surface Water Utility Engineer, x7264 SUBJECT: Saddlcbrook Plat Adjustment 2012-03 The City of Renton Surface Water Utility has completed review of the adjustment request for the Saddlebrook Plat in accordance with City adopted 2009 l(ing County Surface Water Design Manual (KCSWDM) and City Amendments to the 2009 KCSWDM. Our review of the information leads us to understand that the applicant's engineering is requesting an adjustment from the 2009 King County Surface Water Design Manual to core requirement #1 (section 1.2.1), Discharge at the Natural Location. Our review of the information provided by the applicant engineer on August 13, 2012, provides the following finding£: 1. The proposed project has not completed the process preliminary plat approval or SEPA review. 2. The site is located in two existing parcels (3664500260 and 3664500251) with a total area of 4.36 acers. Parcels are situated atop a ridge and discharges runoff into two subbasins. Tributary Drainage Area {TOA) West is approximately 1.78 acres and discharges to 156th Avenue SE while TOA East is comprised of the remaining 2.58 acres and discharges to 158th Avenue SE. The discharge elevation of TOA West is approximately six feet lower than that of TDA East. These two flowpaths converge at a point approximately 3,000 feet downstream of TOA West and 4,900 feet downstream of TOA East at the corner of 155th Avenue SE and SE 144th Street (convergence point). 3. The proposal is to collect much of the runoff from the project site (4.35 acres) and direct it to a single combined detention and water quality facility located iri the west portion of the site. The allowed release would then discharge through an existing conveyance system into the right-of-way of 156th Avenue SE where it continues to go south and converges with TOA East. in SE 144th Street. Jan Illian Page2of4 August 16, 2012 4. No downstream analysis has been completed and submitted to the City for review. However, a preliminary field recognizance of the downstream drainage system was completed by the applicant and applicant's engineer. Findings were discussed in the adjustment letter. Preliminary analysis demonstrated that the downstream path from TDA West is mostly comprised of a constructed conveyance system from the ·site to the convergence point. This conveyance system is made up of grass and rock-lined ditches as well as culverts, pipes, and catch basins. 5. King County drainage complaints in the area were reviewed and the basin draining to the conveyance system was determined using King County iMAP. This resource review revealed an overall basin size of approximately 73.5 acres and no relevant drainage complaints in the last 15 years downstream of the Site. 6. To analyze the impact of the discharge rate, the King County Runoff Time Series Software was used to examine the overall site in a forested condition, TDA West's existing condition, and the 73.5 acre basin in a forested condition as well as a full build-out condition (undetained, based on KCSWDM Table 3.2.2.0 for 4.0 DU/GA, 42% impervious). TDA West (in its existing condition) generates approximately 0.29 cfs of runoff for the 100-year return interval. T)1e total site, when analyzed for the forested condition, will generate approximately 0.35 cfs of runoff for the 100-year return interval. The existing conveyance system downstream of the proposed plat would receive a net increase in runoff of 0.06 cfs, which is less than 0.1 cfs. The total drainage basin currently generates 5,93 cfs and 23.59 cfs, for forested and build-out conditions assuming no flow control, respectively. Based on these understandings, findings, and per section 1.2.1 of the 2009 Surface Water Design Manual as amended by the City, the adjustment to allow the diversion of runoff to a single combined storm water flow control and water quality treatment facility draining to SE 156th Avenue is approved with the following conditions: 1. A level one downstream analysis in accordance with section 1.2.1 of the 2009 KCSWDM as amended by the City shall be submitted to the City for review. Based on this analysis, the City may require the completion ofa downstream analysis and/or improvements to the downstream system. H:\File Sys\SWP -Surface Water Projects\SWP-27 -Surface Water Projects (ClP)\27-3129 Renton Stormwater Ma nu al\ADJ USTMENTS\2012\2012-3 Saddlebroo k.doc\H Bah Jan Jllfan Page 3 of4 August lG, 2012 2. The proposed combined detention and water quality treatment facility to be constructed on the northwest corner of the site shall be designed as a level 3 flow control for the entire site in using the two basins as the existing (forested) site conditions. The stormwater facility shall be designed in accordance with section 1.2.3 of the 2009 KCSWDM. 3. Surface water discharg·e from the west basin is required to follow its existing drainage course. 4. Water quality treatment in accordance with section 1.2.8 of the 2009 KCSWDM shall be provided for all targe.ted surfaces prior to discharging from th.e site. The water qualityfacility shall be sized based on the entire proposed subdivision draining to the facility including any required frontage improvements. 5. The release rate from the detention facility will be based on all of the tributary area being directed to the facility. 5. The vo.lume of the stormwater detention facility shall be based on all flows directed to the facility at full development under current zoning. The detention volume shall be sized using Level 3 Flood Problem Flow Control Standards in the 2009 KCSWDM. The pre-developed condition runoff rates for the sizing of the facility shall be based on the entire site using forested as pre-developed site conditions. The TIR shall include all required document~tion detailed in chapter 2 of the 2009 KCSWDM for the sizing of the facility. 7. Additional storm drainage requirements identified by the City of Renton as part of the SEPA review process or preliminary plat approval may apply to this project. Please note that the approval of this adjustment does not relieve the applicant from other conditions that may be stipulated in future city, state, or federal permits/requirements. Notes to applicant: 1. All lots within the Saddlebrook Plat are required to provide flow control BMPs in accordance with figure C.1.3.A of the 2009 KCSWDM. Flow control BMP credits in accordance with section 1.2.3 of the 2005 KCSWDM may be used to reduce the size of the required flow control facility. The feasibility to implement full · dispersion BMPs and full infiltration BMPs shall be verified first. If implementation of full dispersion BMPs and full infiltration BMPS are not feasible alternatives, then any of.the BMPs listed in figure C.1.3.A shall be provided. The selected flow control BMP to be implemented on each lot shall be shown on the co.nstruction plans. Drainage calculations for the sizing of the proposed BMPs to be constructed on each lot shall be included in the TIR. H:\File Sys\SWP-Surface Water Projects\SWP-27 -Surface Water Projects {CIP)\27-3129 Renton Stormwater Manual\ADJUSTMENTS\2012\2012-3 Saddlebrook.doc\HBah Jan Illian Page4of4 August 16, 2012 Construction of the proposed flow control BMPs may be differed for construction on the lot at time of building permit. If you have any questions about this adjustment, please contact Hebe Bernardo or me. Attachments cc: Lys Hornsby, P.E., Utility Systems Director Kayren Kit:t:ri_ck, Development Engineering Supervisor Vanessa Dolbee, Planner File H:\File Sys\SWP -Surface Water Projects\SWP-27 -Sutface Water Projects {CIP)\27-3129 Renton Stormwater Ma nual\ADJ USTMENTS\2012\2012·3 Saddlebrook.doc\H Bah PUBLIC WORKS DEPARTMENT M E M O R A N D U M DATE: October 31, 2012 TO: Arneta Henninger, Plan Reviewer FROM: Ron Straka, Surface Water Utiiity Supervisor, x7248 STAFF CONTACT: Hebe C. Bernardo, Surface Water Utility Engineer, x7248 Saddlebrook Plat-ADS Bay Filter™ Adjustment 2012-04 SUBJECT: The City of Renton Surface Water Utility has completed review of the adjustment request from. DR Strong Consultant Engineer for the Saddlebrook Plat in accordance with City adopted 2009 King County.Surface Water Design Manual (KCSWDM) and City Amendments to the 2009 KCSWDM. Our review of the information leads us to understand that the applicant's engineering is requesting an adjustment from the 2009 King County Surface Water Design Manual.to core requirement #8), Water Quality. Our review of the information provided by the applicant engineer on October 16, 2012, provides the following findings: 1. The proposed project has not completed the process preliminary plat approval or SEPA review. 2. The site is located in two existing parcels (3664500260 and 3664500261) with a total ar~a of4.36 acres. Paree ts are situated atop a ridge and discharges runoff into two sub-basins. An adjustment to Core Requirement 111, Discharge at the Natural Location was approved in December 11, 2012 allowing the project to collect much of the runoff from the project site (4.36 acres) and direct it to a single combined detention and water quality facility located in the west portion of the site. The adjustment request proposes to use the BayFilter'" System for Basic Water Quality treatment. The Washington State Department of Ecology has approved the BayFilter'" System for General Use Level Designation for Basic Water Quality treatment. Based on the information provided in the adjustment request; the BayFilter'" System for Basic Water Quality Treatment is approved with the following conditions: 1. _The water quality design flow shall be as follows, whichever is applicable: a. Downstream offlow control facility: The full 2-year pre-developed allowable rate release rate from the flow control facility. Ms. Henninger Page2of3 October 31, 2012 2. The Storm Filter system shall be sized as described in the BayFilter™ Technical and Design Manual, and the designer shall select the result yielding the larger number of cartridges. 3. Pre-settling shall be provided per Section 6.5.1 of the 2009 KCSWDM, General Requirements for Media Filtration Facilities. 4. BayFilter'M systems shall be installed in such a manner that the flows exceeding the design flow rates are bypassed around the Bayfilter Water Quality treatment facility. An external bypass to handle flow exceeding the facility design shall be provided. 5. The following maximum flow rates per cartridge system is limited to the following: a. BayFilterCartridge (BFC) Cartridge maximum flow rate of0.7 gpm/sf. i. 30 gpm (0.067 cfs) per cartridge (43 sf filter area). ii. 26 inches in diameter and approximately 28.75 inches tall. 6. Media combinations for the BayFilter'" cartridges are limited to Silica Sand, Perlite, Zeolite, and Activated Alumina. All filters are limited to the 19" vertical component to the spiral filter layers. 7. Vaults used for the BayFilter™ System shall conform to the "Materials" and "Structural Stability" requirements specified in Section 5.3.3 of the 2009 KCWDM for detention vaults. 8. The BayFilter'" system must be installed in an area that is accessible to maintenance equipment. The maintenance of a BayFilter'" system requires a vacuum truck as well as the removal and replacement of the filter cartridges. The manhole covers, and/or access hatches of the BayFilter'" System must be placed in locations that can be easily reached by such a vehicle. 9. Access Requirements: a. Access consistent with City confined entry policy must be provided by either removable panels or other City approved accesses to allow for removal and · replacement of the BayFilter cartridges. Approved access details for the Storm Filter system may be used as example and are available in Reference Section 7C of the 2009 KCSWDM. b. Removable panels, if used, shall be at grade, have stainless steel lifting eyes, and weigh no more than 5 tons per panel. c. Access to the inflow and outlet cells must also be provided. d. Ladder access is required whe·n vault height exceeds 4 feet. e. Structures and access covers shall be designed for HS20 traffic loading. f. Removable panel access for vault shall not be located within the street pavement section. 10. !nstailation of a 8ayFilter™ system shall follow the manufacturer 1s recommended procedures. H:\File Sys\SWP -Surface Watt:r Projects\SWP-27 -Surface VJater Projects. (CIP)\27-3129 Renton Stormwater Manua!\ADJUSTMENTS\2012\2012-4 Sattlebrook Plat-bayfi!ter.doc\H82h Ms. Henninger Page3of3 October 31, 2012 11. The Bay Filter'" system shall be inspected every six (6) months during the 2-year maintenance defect bond period following completion of construction and plat recording .. The owner is responsible for the_ maintenance of the Bay Filter'" system during the 2-year defect bod period. The City will maintain the facility after the two year maintenance and defect bond period expires. 12. When Bay Filter exhibits flows below design levels, the system should be inspected and maintained as soon as practical. Replacing a Bay Filter cartridge should be considered at or above the level of the 4" collector pipes to the manifold. Maintenance procedures can be found in the BayFilter System Technical and Design Manual. The maintenance process comprises the removal and replacement of each BayFilter cartridge and the cleaning of the vault or manhole with a vacuum truck. 13. This is a conceptual approval for using the Bay Filter for Basic Water Quality Treatment. Further analysis and design calculations shall be included in the TIR for final approval. 14. The approval of this adjustment to use the BayFHter System for the Saddle brook Plat does not authorize the use of the BayFilter System on future projects without prior approval from the City of Renton. 15.-The BayFilter system shall be installed in accordance with the approved drawings and shall not be located within City right-of-way or easements. Please note that the approval of this adjustment does not relieve the applicant from other city, state, or federal requirements. If you have any questions about this adjustment, please contact Hebe C. Bernardo or me. Attachments cc: Lys Hornsby1 P.E., Utiiity Systems Director Kayren Kittrick, Development Engineering Supervisor Richard Marsha!, Surface Water and Water Maintenance Manager Vanessa Dolbee, Planner File H:\File Sys\SWP-Surface Weiter Projects\SWP-27-Surface Water Projects (CIPj\27-3129 Renton Stormwater Mein ual\A DJUSTMENTS\2012\2012-4 Sattlebrook Plat-bayfi!ter.doc\HBah SECTION VIII ESC PLAN ANALYSIS AND DESIGN (PART A) The Erosion and Sedimentation Control Design will meet the nine minimum requirements: 1. Clearing Limits -Areas to remain undisturbed shall be delineated with a high visibility plastic fence prior to any site clearing or grading. 2. Cover Measures -Site disturbed areas shall be covered with mulch and seeded, as appropriate, for temporary or permanent measures. 3. Perimeter Protection -Perimeter protection shall consist of a silt fence down slope of any disturbed areas or stockpiles. 4. Traffic Area Stabilization -A stabilized construction entrance will be located at the point of ingress/egress. 5. Sediment Retention -The proposed detention pond will be used as a sediment pond. 6. Surface Water Control -Surface water control will be provided by interceptor swales. 7. Dewatering Control -Not Applicable to this Site. 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 -Flow control will be provided by the detention pond. SWPPS PLAN DESIGN (PART B) Construction activities that could contribute pollutants to surface and storm water 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 (TSO) 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 © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 41 Saddlebrook Div. II Renton, Washington 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. The complete CSWPPP will be provided prior to final engineering approval. © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 42 Saddlebrook Div. II Renton, Washington SECTION IX BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 1. Bond Quantity Worksheet -will be provided prior to final engineering approval. 2. Facility Summary-attached. 3. Declaration of Covenant -will be provided prior to final engineering approval. © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 43 Sadd!ebrook Div. II Renton, Washington STORMWATER FACILITY SUMMARY SHEET Development Saddlebrook Div. I and Div. II Date April 30, 2013 Location 13422 1561h Avenue SE, Renton, Washington ENGINEER DEVELOPER Name Maher A. Joudi, P.E. Name Firm D. R. STRONG Consulting Firm: ACH Homes, LLC Engineers, Inc. Address 10604 NE 38'" Place, #232 Address 9675 SE 36'" Street,# 105 Kirkland, WA 98033 Mercer Island, WA 98040 Phone (425) 827-3063 Phone (206) 588-1147 Developed Site: 5.54 acres Number of lots Seventeen (Total for Div. I and Div. Ill Number of detention facilities on site: _ _,1'--pond vaults ---tanks --- Number of infiltration facilities on site: ponds --- vaults --- tanks ---Flow control provided in regional facility (give location) ______________ _ No flow control required __ Exemption number D ownstream D . ra1naqe B . as1ns Immediate Major Basin Basin Lower Cedar River Cedar River Number & type of water quality facilities on site: ___ biofiltration swale (regular/weU or continuous inflow?) ___ sand filter (basic or large?) large?) 1 detention pond ___ combined detention/wetvault ___ compost filter ___ filter strip 34 flow dispersion ___ farm management plan © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report ---sand filter, linear (basic or 1 BayFilter ___ sand filter vault (basic or large?) stormwater wetland --- ---wetpond (basic or large?) wetvault --- ___ pre-settling pond ---flow-splitter catchbasin 44 Saddlebrook Div. II Renton, Washington ___ landscape management plan ___ oil/water separator (baffle or coalescing plate?) catch basin inserts: --- Manufacturer --------------------- --,----pre-settling structure: Manufacturer ___________________ _ DESIGN INFORMATION Water Quality design flow Water Quality treated volume Drainaoe basin(s) Onsite area (inlcudes frontage) Offsite area Type of Storage Facility Live Storaoe Volume (required) Predev Runoff Rate Developed Runoff Rate (Including Bypass Rate) Type of Restrictor Size of orifice/restriction © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 2-year 10-year 100-vear 2-year 10-year 100-year No. 1 No. 2 No. 3 No. 4 INDIVIDUAL BASIN East 2 5.54 ac. 0 Pond 62,868 0.154 0.268 0.447 0.083 0.228 0.444 Froo-Tee 1.11 2.14 2.54 N/A 45 Saddlebrook Div. II Renton, Washington 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. © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 46 Saddlebrook Div. II Renton, Washington © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report APPENDICES 47 Saddlebrook Div. II Renton, Washington APPENDIX "A" LEGAL DESCRIPTION THE SOUTH 130 FEET OF LOT 5 IN BLOCK 2 OF JANETT'S RENTON BOULEVARD TRACTS, ACCORDING TO PLAT RECORDED IN VOLUME 17 OF PLATS AT PAGE(S) 60, IN KING COUNTY, WASHINGTON; EXCEPT THE EAST 290 FEET THEREOF. © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 48 Saddlebrook Div. II Renton, Washington APPENDIX "B" BOND QUANTITY WORKSHEET This will be provided during final engineering. © 2013 D. R. STRONG Consulting Engineers Inc. Technical Information Report 49 Saddlebrook Div. II Renton, Washington APPENDIX "C" OPERATIONS AND MAINTENACE MANUAL © 2013 0. R. STRONG Consulting Engineers Inc. Technical Information Report 50 Saddlebrook Div. ll Renton, Washington APPENDIX A MAINTENANCE REQUJREMENTS PLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 1 -DETENTION PONDS 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 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 oll film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Top or Side Slopes Rodent holes Any evidence of rodent holes if facility is acting Rodents removed or destroyed and of Dam, Berm or as a dam or berm, or any evidence of water dam or berm repaired. Embankment piping through dam or berm via rodent holes. Tree growth Tree growth threatens integrity of slopes, does Trees do not hinder facility not allow maintenance access, or interferes with performance or maintenance maintenance activity. If trees are not a threat or activities. not interfering with access or maintenance, they do not need to be removed. Erosion Eroded damage over 2 inches deep where cause Slopes stabilized using appropriate of damage is still present or where there is erosion control measures. If erosion potential for continued erosion. Any erosion is occurring on compacted slope, a observed on a compacted slope. licensed civil engineer should be consulted to resolve source of erosion. Settlement Any part of a dam, berm or embankment that has Top or side slope restored to design settled 4 inches lower than the design elevation. dimensions. If settlement is significant, a licensed civil engineer should be consulted to determine the cause of the settlement. Storage Area Sediment Accumulated sediment that exceeds 10% of the Sediment cleaned out to designed accumulation designed pond depth. pond shape and depth; pond reseeded if necessary to control erosion. Liner damaged Liner is visible or pond does not hold water as Liner repaired or replaced. (If Applicable) designed. Inlet/Outlet Pipe. Sediment Sediment filling 20% or more of the pipe. Inlet/outlet 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-floatab!es). Damaged Cracks wider than %-inch at the joint of the No cracks more than X-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. Emergency Tree growth Tree growth impedes flow or threatens stability of Trees removed. Overflow/Spillway spillway. Rock missing Only one layer of rock exists above native soil in Spillway restored to design area five square feet or larger or any exposure of standards. native soil on the spillway. 1/9/2009 2009 Surface Water Design Manual -Appendix A A-2 APPENDIX A MAINTENANCE REQUIREMENTS FOR 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 Structure Trash and debris Trash or debris of more than% cubic foot which No Trash or debris blocking or is located immediate!y in front of the structure potentially blocking entrance to opening or is blocking capacity of the structure by structure. more than 10%. Trash or debris in the structure that exceeds 1 /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 !owe st 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 Y.t inch. Frame not sitting flush on top slab, i.e., Frame is sitting flush on top s!ab. 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 Yz inch and longer than 1 foot No cracks more than 1h inch wide at at the joint of any inlet/outlet pipe or any evidence the joint of inleUout!et pipe. of soil particles entering structure through cracks. SettlerrienU 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 %-inch at the joint of the No cracks more than X.-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of inlet/outlet pipes. the structure 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. Ladder rungs missing Ladder is unsafe due to missing rungs, Ladder meets design standards and or unsafe misalignment, rust, cracks, or sharp edges. allows maintenance person safe access. FROP-T Section Damage T section is not securely attached to structure T section securely attached to wall wall and outlet pipe structure should support at and outlet pipe. least 1,000 lbs of up or down pressure. Structure is not in upright position (allow 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 Manual-Appendix A 1/9/2009 A-7 APPENDIX A MAINTENANCE REQUIREMENTS 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 Gale 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 P!ate 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. Deformed or damaged Lip of overflow pipe is bent or deformed. Overflow pipe does not allow lip overflow at an elevation lower than design lnleVOutlet Pipe Sediment Sediment filling 20% or more of the pipe. Inlet/outlet 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 Yz-inch at the joint of the No cracks more than Xi-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inleUoutlet pipes. Metal Grates Unsafe grate opening Grate with opening wider than 7 /8 inch. Grate opening meets design (If Applicable) 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 standards. Manhole Cover/Lid 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 Cover/lid can be removed and Remove cover/lid after applying 80 !bs. of lift. reinstalled by one maintenance person. 1/9/2009 2009 Surface Water Design Manual-Appendix A A-8 APPENDIX A MAINTENANCE REQUIREMENTS FOR 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 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 !owe st 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 oris 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. 1 /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 (lf applicable). Top slab has holes larger than 2 square inches or Top s!ab is free of holes and cracks. cracks wider than X 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. 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 % inch and longer than 1 foot No cracks more than 1 /4 inch wide at at the joint of any inleVoutlet pipe or any evidence the joint of inleVoutlet pipe. of soil particles entering catch basin through cracks. Settlement! 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 X-inch at the joint of the No cracks more than /'4-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of inleVout!et pipes. the catch basin 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 fi!m. lnleVOutlet Pipe Sediment Sediment filling 20% or more of the pipe. Inlet/outlet 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-floatab!es). Damaged Cracks wider than Yz-inch at the joint of the No cracks more than %-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-9 APPENDIX 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 7 /8 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 Cover/Lid 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 difficu·lt to One maintenance person cannot remove Cover/lid can be removed and Remove cover/lid after applying 80 lbs. of lift. reinstalled by one maintenance person. 1/9/2009 2009 Surface Water Design Manual-Appendix A A-10 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 6 -CONVEYANCE PIPES AND DITCHES Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed 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 if 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. 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 public. regulations. No danger of noxious vegetation where County personnel or the public might normaJ1y be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of po!Jution as oi!, gasoline, concrete slurries or paint. according to applicable regulaUons. 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 (!f area 5 square feet or more, any exposed native Applicable) soil. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-11 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 7 -DEBRIS BARRIERS (E.G., TRASH RACKS) Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed. Site Trash and debris Trash or debris plugging more than 20% of the Barrier clear to receive capacity flow. area of the barrier. Sediment Sediment accumulation of greater than 20% of Barrier clear to receive capacity flow. accumulation the area of the barrier Structure Cracked broken or Structure which bars attached to is damaged -Structure barrier attached to is loose pipe is loose or cracked or concrete structure is sound. cracked, broken of loose. Bars Bar spacing Bar spacing exceeds 6 inches. Bars have at most 6 inche spacing. Damaged or missing Bars are bent out of shape more than 3 inches. Bars in place with no bends more bars than% inch. Bars are missing or entire barrier missing. Bars in place according to design. Bars are loose and rust is causing 50% Repair or replace barrier to design deterioration to any part of barrier. standards. 119/2009 2009 Surface Water Design Manual -Appendix A A-12 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 9 -FENCING Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected 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 parts more than 6 inches or cross members broken broken boards, post plumb to within 1 X inches, cross members sound. Weakened by rotting Any part showing structural deterioration due to All parts offence 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 1Yz inches. 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 APPENDIX A MAINTENAi'ICE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, 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 aligned and vertical. more than 1 foot out of design alignment. Missing stretcher bar, stretcher bands, and ties. Stretcher bar, bands, and ties in place. 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 !ink 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 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 faclllty. 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 faci!ity. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-15 APPENDIX A MAINTENA,"\ICE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 11 -GROUNDS (LANDSCAPING) 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 1,000 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 shou!d 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 tha'n 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 Umbs or parts of trees or shrubs that are split or broken which affect more than 25% of the total Trees and shrubs with less than 5% 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 place and supported or are leaning 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 fill up vehicles. one standards size garbage can). Debris which could damage vehicle tires or Roadway drivable 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 applicable regulations. 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 !east 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 1 O 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 Swface Water Design Manual -Appendix A 1/9/2009 A-17 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 20 -SAND FILTER VAULT Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from facility site. 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. Gr.ass/groundcover Grass or groundcover exceeds 18 iriches in Grass or groundcover mowed to a height. height no greater than 6 inches. Pre-Treatment Sediment Sediment accumulation exceeds the depth of the Sediment storage contains no Chamber accumulation sediment zone plus 6 inches. sediment. Sand Filter Media Sediment Sediment depth exceeds %-inch on sand filter Sand filter freely drains at normal accumulation media. rate. Trash and debris Trash and debris accumulated in vault (floatables No trash or debris in vault. and non-floatables). Plugging Drawdown of water through the sand filter media, Sand filter media drawdown rate is takes longer than 24 hours, and/or flow through normal. the overflow pipes occurs frequently. A sieve analysis of >4% -100 or >2% -200 requires replacing sand filter media. Short circuiting Seepage or flow occurs along the vault walls and Sand filter media section re-laid and corners. Sand eroding near inflow area. compacted along perimeter of vault Cleanout wyes are not watertight. to form a semi-seal. Erosion protection added to dissipate force of incoming flow and curtail erosion. Vault Structure Damaged to walls, Cracks wider than Yz-inch, any evidence of soil Vault replaced or repaired to provide frame, bottom and/or entering the structure through cracks or qualified complete sealing of the structure. top slab. inspection personnel determines that the vault is not structurally sound. Ventilation Ventilation area blocked or plugged. No reduction of ventilation area exists. Underdrains and Sediment/debris Underdrains or clean-outs partially plugged, filled Underdrains and clean-outs free of Cleanouts with sediment and/or debris or not watertight. sediment and debris and sealed. lnleUOutlet Pipe Sediment Sediment filling 20% or more of the pipe. Inlet/outlet pipes c!ear 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 Yz-inch at the joint of the No cracks more than %-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. 1/9/2009 2009 Surface Water Design Manual-Appendix A A-28 APPENDIX A MAJNTENANCE REQUffiEMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 20 -SAND FILTER VAULT Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed 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 cover/lid after applying 80 lbs 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. 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 Ifft or rusted or plate. remove door or plate. 2009 Surface W atcr Design Manual -Appendix A 119/2009 A-29 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 24-CATCH BASIN INSERT Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Media Insert Visible Oil Visible oil sheen passing through media Media inset replaced. Insert does not fit Flow gels into catch basin without going through A!! flow goes through media. catch basin properly media. Filter media plugged Filter media plugged. Flow through filter media is norm a!. Oil absorbent media Media oil saturated. Oil absorbent media replaced. saturated Water saturated Catch basin insert is saturated with water, which Insert replaced. no longer has the capacity to absorb. Service life exceeded Regular interval replacement due to typical Media replaced at manufacturer's average life of media insert product, typically one recommended interval. month. Seasonal When storms occur and during the wet season. Remove, clean and replace or install maintenance new insert after major storms, monthly during the wet season or at manufacturer's recommended interval. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-35 APPENDIX "D" CSWPPP This will be provided during final engineering. © 2013 D.R. STRONG Consulting Engineers Inc. Technical Information Report 51 Saddlebrook Div. II Renton, Washington D.R. STRONG CONSULTING ENGINEERS