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Home My WebLink AboutMiscENGINEERING REPORT Technical Information Report Renton Highlands Library Site Plan Review December 16t; 2013 PREPARED FOR: King County Library System 960 Newport Way NW Issaquah, WA 98027 (425) 369-3200 PREPARED THROUGH: THA Architecture 733 SW Oak Street Portland, OR 97205 Phone: (503) 227-1254 Contact: Scott Mooney PREPARED BY: CO UG H LI N PORTERLU N D E EN 413 Pine Street, Suite 300 Seattle, Washington 98101 P: 206/343-0460 Contact: Bart Balko, P.E. TECHNICAL INFORMATION REPORT AND HYDROLOGIC ANALYSIS Renton Highlands Library Coughlin Porter Lundeen Project No. C131436-01 December 16'1,, 2013 TABLE OF CONTENTS Section Page I. PROJECT OVERVIEW.................................................................................................................................................1 GENERALDESCRIPTION..................................................................................................................................................... I EXISTINGCONDITIONS ..........-'........................................................................................................................................ 1 PROPOSEDDRAINAGE SYSTEM.......................................................................................................................................... 1 11. CONDITIONS AND REQUIREMENTS SUMMARY............................................................................................. 2 CITY OF RENTON AMENDMENTS TO THE KING COUNTY SURFACE WATER MANAGEMENT DESIGN MANUAL CORE REQUIREMENTS: ................................................................................................................................................................. 2 SPECIALREQUIREM ENTS:............................................................ ............................................................................. ......... 2 PROJECT SPECIFIC REQUIREMENTS:..................................................................—,............................................................. 3 111. OFF-SITE ANALYSIS................................................................................................................................................. 4 TASK I — STUDY AREA DEFINITION AND MAPS................................................................................................................. 4 TASK2 - RESOURCE REVIEW............................................................................................................................................. 4 TASK3 - FIELD INSPECTION............................................................................................................................................... 4 TASK 4 - DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS...................................................................... 4 UPSTREAMANALYSIS....................................................................................................................................... ............... 4 DOWNSTREAMANALYSIS.................................................................................................................................................. 4 TASK 5 -- MITIGATION OF EXISTING OR POTENTIAL PROBLEMS......................................................................................... 4 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN .................................... 6 EXISTING SITE HYDROLOGY (PART A).............................................................................................................................. 6 DEVELOPED SITE HYDROLOGY (PART B).......................................................................................................................... 6 PERFORMANCE STANDARDS AND FLOW CONTROL SYSTEM (PARTS C AND D)................................................................ 6 WATERQUALITY SYSTEM (PART E).................................................................................................................................. 7 STANDARDREQUIREMENTS............................................................................................................................................... 7 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN............................................................................................ 8 STANDARD REQUIREMENTS (BASED ON KCSWDM AND SAO): ...................................................................................... 8 ON-SITE CONVEYANCE...................................................................................................................................................... 8 VI. SPECIAL REPORTS AND STUDIES....................................................................................................................... 9 VII.OTHER PERMITS...................................................................................................................................................10 VIII. CSWPPP ANALYSIS AND DESIGN...................................................................................................................11 STANDARDREQUIREMENTS.................•--.--..................................................................................................................... I I IX. BOND QUANTITY, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ..........................12 X. OPERATION AND MAINTENANCE MANUAL.................................................................................................13 STANDARDMAINTENANCE.............................................................................................................................................. 13 COUGHUNPORTERLUNDEEN Renton Highlands Library 1 Renton, Washington Figure 1- TIR Worksheet Figure 2 -- Parcel Conditions Figure 3 - Site Location Figure 4 - Storm GIS Layout Figure 5 - Drainage Basin Map Figure 6 - Flow Control Map Figure 7 - King County iMAP - Floodplain Figure & W City of Renton Soil Survey Map Figure 9 - Drainage Complaints Map Figure 10 - KCRTS Peak Flow Calculations LIST OF FIGURES LIST OF TABLES Table 1- Existing Site Conditions Area Breakdown...................................................................... Table 2 - Developed Site Conditions Area Breakdown............................................................ COUGHLINPORTERLUNDEEN Renton Highlands Library �� Renton, Washington King County Department of Development and Environmental Services Figure 1: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Project Owner: King County Library System Address: 960 Newport Way NW Issaquah, WA 98027 Phone: 425-369-3200 Project Engineer: Bart Balko, P.E. Company: Coughlin Porter Lundeen Address/Phone: 413 Pine Street, Ste 300 Seattle, WA 98101 206 343-0460 Part 3 TYPE OF PERMIT APPLICATION ❑ Subdivison ❑ Short Subdivision ❑ Grading ❑ Commercial ® Other: SPR Part 2 PROJECT LOCATION AND DESCRIPTION Project Name: Renton Highlands Library Location Township: 23N Range: 5E Section: 9 Part 4 OTHER REVIEWS AND PERMITS ❑ DFW HPA ❑ Shoreline Management ❑ COE 404 ❑ Rockery ❑ DOE Dam Safety ❑ Structural Vaults ❑ FEMA Floodplain ❑ Other ❑ COE Wetlands ❑ Groundwater Recharge Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community: Renton Highlands Drainage Basin: Lake Washington East Drainage Basin Part 6 SITE CHARACTERISTICS ❑ River ❑ Floodplain ❑ Stream ❑ Wetlands ❑ Critical Stream Reach ❑ Seeps/Springs ❑ Depress ions/Swa les ❑ High Groundwater Table ❑ Lake ❑ Groundwater Recharge ❑ Steep Slopes ❑ Other Part 7 SOILS Soil Type Brown, rusted sand with gravel, moist, loose ill on top of light gray, silty sand with gravel that is fine to medium grained, moist, and very dense. Slopes Erosion Potential 0-3% ❑ Additional Sheets Attached Erosive Velcoties Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION ❑ Sedimentation Facilities ® Stabilized Construction Entrance ® Perimeter Runoff Control ® Clearing and Graing Restrictions ® Cover Practices ® Construction Sequence ❑ Other 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 ❑ Flag Limits of SAO and open space preservation areas ❑ Other Part10 SURFACE WATER SYSTEM Cast in Place Vault ❑ Retaining Wall ❑ Grass Lined ❑ Tank ❑ Infiltration Method of Analysis Channel ❑ Vault ❑ Depression ® Pipe System ❑ Energy Dissapator El Flow Dispersal Corn pen sat ionlMitigati ❑ Open Channel ❑ Wetland❑ Waiver on of Eliminated Site ❑ Dry Pond ❑ StreamStorage ❑ Regional ❑ Wet Pond Detention Brief Description of System Operation A rain garden will be used.lt will have an underdrain and be piped to to public storm system in the right-of-way. Facility Related Site Limitations Reference Facility Limitation Part 11 STRUCTURAL ANALYSIS ❑ Cast in Place Vault ❑ Retaining Wall ❑ Rockery > 4' High ❑ Structural on Steep Slope ❑ Other Part 12 EASEMENTSITRACTS ❑ Drainage Easement ❑ Access Easement ❑ Native Growth Protection Easement ❑ Tract ❑ Other Part 13 SIGNATURE OF PROFESSIONAL ENGINEER I or a civil engineer under my supervision my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attachments. To the best of my knowledge the information provided here is accurate_ December 1 B, 2013 Figure 2 - Parcel Conditions kg King County King County Districts and Development Conditions for parcel 7227801085 Parcel number 7227801085 Drainage East Lake Washington = does not Address 970 HARRINGTON Basin - Renton Development conditions None town % AVE NE Vvaterst ed Cedar River i Lake ater_ser✓ice plannincrea does not Jurisdiction Renton Washington Con muni-,� 5ervice Area Zipcode 98056 �:�RIA Cedar-Sammamish (8) Newcastle Kroll Map page 369 PLSS NW - 9 - 23 - 5 �ortation_C�c�ncurrencv �r�a erlIenl Thomas Guide 626 Latitude 47.5001 No page None mapped Longitude -122.18151 Electoral Districts :r'rtinra di�i�c Kin�C, r :y Council dEstrir..t Congressional district Legislative district School district Seattle school board district District Court electoral district RNT 11-0980 District 9, Reagan Dunn (206) 296-1009 LO 9 11 Renton 9403 does not apply (not in Seattle) Southeast Fire district Water district Sewer district Water & Sewer district Parks & Recreation district Hospital district Rural library district Tribal Lands? does not apply does not apply does not apply does not apply does not apply Public Hospital District No. 1 Rural King County Library System No King County planning and critical areas designations Kirig C ;iv Unzoniry NA, check with Pa7er-ia annex'itionarea - _ does not jurisdiction apply Development conditions None town % No Ccrnare' erswe Plan does not apply ater_ser✓ice plannincrea does not Urban Grc _;h A ea Urban apply Con muni-,� 5ervice Area does not apply -cads t'°I 5 1nne 445 �j' ng_Area Newcastle �r. , �� does not Coal mine hazard s. None mapped �ortation_C�c�ncurrencv �r�a erlIenl apply Erosion hazards? None mapped Forest Production district? No Landslide hazards? None mapped Agricultural Production district? No Seismic hazards? None mapped C- tical aquifer recharge areal None mapped 100 -year flood plain? None mapped Wetlands at this parcel? None mapped This report was generated on 10/10/2013 1:19:02 PM Contact us at nEscenter(ci l inuct Linty Cov. 9 2010 King County [Figure 3 - Site Location COUGHLINPQRTERLUNDEE N STRUCTURAL • CIVIL • SEISMIC ENGINEERING 'f, t ~{� �.T Project: Renton Hi hlands Library Designed By: CNB Date: 10-10-13 Project No, C13-14336-01 Client: THA Architects Checked By: BSB Sheet 1 of 1 413 PINE STREET - SUITE 300 • SEATTLE. WA • 98101 P: 2061343-0460 . F: 2061343-5691 Z W W a z D J ol� LU 0 IOL Z J D 0 V C2 LL CD 00 C) CO V) c= 0 L L L J Basin Locations o 05 , Miles Surface Water Utility Comprehensive Plan Printed 10116/2009 City of Renton City Limits Potential Annexation Area Basins Black River Duamish Lake Washington East f" Lake Washington West Lower Cedar River May Creek Soos Creek Figure 5 - Drainage Basin Map II. CONDITIONS AND REQUIREMENTS SUMMARY This section will address the requirements set forth by the Core and Special Requirements listed in Chapter 1 of the City of Renton s Amendments to the King County Surface Water Design Manual_ City of Renton Amendments to the King County Surface Water Management Design Manual Core Requirements: 1. Discharge at the Nahiral Location 1.2.1: All developed flows will be conveyed to the existing closed conveyance system on the site and directed to Lake Washington. 2. Off-site Analysis (1.2.2): Refer to Sections III and IV. A Level 1 downstream analysis has been performed 3. Flow Control 1.2.3.1: Refer to Section IV. As the threshold discharge area in which target surfaces subject to flow control will not generate more than a 0.1-cfs increase in the existing site condition's 100 - year peak flow, detention is not required. 4. ConMance System (1.2.4): Refer to Section V. Closed pipe systems have been provided for on-site stormwater conveyance. 5. Erosion and Sedimentation Control (1.2.5): Refer to Section VIII. The project will construct a series of sediment controls to address the specific conditions at the site. 6. Maintenance and Operations 7.2.6: Refer to Section X. The proposed storm drainage system will be owned, operated and maintained by the owner. 7. Financial Gtaarantees and Liabili 1.2.7: The owner and contractor will obtain all necessary permits prior to the beginning of construction. The City of Renton/King County Library System (KCLS) will be responsible for required bonds. &. Water Quality (1.2.8): Refer to Section IV.E. Water quality treatment is not required as part of this development because no pollution generating surfaces are being added or replaced and the project is under the threshold. Special Requirements: Special Requirement #1. Other Adopted Area -Specific Requirements Section 1.3.1 • Critical Drainage Areas (CDAs): Not Applicable • Master Drainage Plans (MDPs): There are no known master drainage plans covering this project site. • Basin Plans (BPs): The project is located within Lake Washington Drainage Basin. • Lake Management Plans(LMPs): Not Applicable • Shared Facility Drainage Plans(SFDPs): Not Applicable Special Requirement #2. Flood Hazard Area Delineation, Section 1.3.2: See Figure 7 for 140 -yr flood zone. No work affecting the flood storage will take place within the 100 -yr flood zone. Special Requirement #3. Flood Protection Facilities, Section 1.3.3: Not Applicable Special Requirement #4. Source Controls, Section 1.3.4: See attached Activity Worksheet and Required BMP's. Special Requirement #5. Oil Control: Minimal traffic is anticipated in this area. No oil control is required. COUGH LINPORTERLUN D E E N Renton Highlands Library 2 Renton, Washington Project Specific Requirements; There are no additional requirements for this portion of the project. Design and construction will abide by requirements set forth in these documents and King County, COUGHLINPORTERLUNDEEN Renton Highlands Library Renton, Washington Figure 6 -Flow Control Map Flow control Application Map Printed 1/1412010 r r C f ,0!�� ' Miles -' Flow Control Standards -- `� xi 'j Sw211Sty Peak Rate Flow Control Standard {Existing Site Conditions) Flow Control Duration Standard (Existing Site Conditions) a _ Flow Control Duration Standard (Forested Conditions) L..�... Renton City Limits �y $E az t Potential Annexation Area Wa SI 3B a btu C a n WN rn S a i t < PR fL_ SE 18E1h St i E' 1N rn SE 112N St os is 190th 190th SE 116 -�JE fllh it SE 120th 120thNEN SI w _ .... 3j St ! Sy 1214tR $ A ., - SE tar PI 196t S q' NE 411, St z'. _ f q E 128th � S q j 1'E 2,d SI 132n SI xl St o' z m — m 169 N� tfi ✓i 5 m - Flow control Application Map Printed 1/1412010 r r C f ,0!�� ' Miles -- `� Sw211Sty - 167 S 82nC SI 0 Wa SI 3B a btu C a n a a SE 18 S 4 5 PI Sr 184h S eft St S fL_ SE 18E1h St i rn E iaM St is 190th 190th - +4 1 q H 196t S q '} � S I St 'm N� tfi ✓i 5 m - q N - m � Flow control Application Map Printed 1/1412010 r r C f ,0!�� ' Miles Figure 7 - Floodplain L,-- 1. Seattle SE lip se t its M ISIS'nd Bellevue L I'X tic lux .0 Y �T Al� AL J r— I XE A- Z, I M1.2 f -f -JI 0 Ne. sale �``_} ti Lake Boren _77o t37f III 'HEIV0774LOY774I01 A, ..;W, Te Wd Ington Cake rr MA 7b I IY 3 7 H !M!,A' W I SC8335 37UN j. L Mc vu 6 4.A Project Site 7C MA Y4 -MA, GW 5 8C8.3391 ti -W ' NL -2TH 3T f 60 ;xy2 entan zh I z I'M Z HIE 4.T 2SE 128,to J32ND' Sr r ....... ....... ....... ....... +32 ON < 46 J 03 Z (1117-41 31W .14 X, —. . ."I - . SP -Q8174390 31P 0 -IG Ce a Legend + ACrive 6: C— .crew100 Y— Floodplain41 e6+ 77 Rivers N P.J,.� C—ty B—dary Large X Mountain Punks Mgh.." Incorporated A— C—ci -J + —T i4 iinn Wafer Resource TuMN '11— Ffgrlg Coliinty W.—ge San— King Ce GR 3 #4 r\ La Ves ZM King County ent .001 58288 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 WaffartlelS, express or implied, as to accuracy. completeness, timeliness, or rights to the use of such information. This document is not intended for use as a survey product King County shall not be liable for any general, special, indirect, incidental, or consequential damages including, but riot 4mited bn, lost revenues or lost profits rerulling from the use or misuse of the information contained on this map. Any 'Sala of this map of information on this map is prohibited except by written permission of King County. LQ King County Dale: 10110I2013 Source King County iMAP - Hydrographic Information (http:lMww.metrc)kc.goviGiSliMAP) Hy d raga uge s ACTIVE -4,._ 1naC110C f� f County Boundary X Mountain Peaks Highways King County Drainage Basins Streets Nlghwvy (Gont) NAP 5 : 9tAkag uXnlsh (Cont) 1: snohomtsh 8: Cadz-SvnMaFnrsh 9: Dawarnimh -Gram 14: Puyallup -whoa 11 : Nrsqualty 12: C hantw-s C icmr i ne mro,"anon ,nCiudeo on this map has been Compiled by King County staff from a variety of sources and is subject in change without notice. Kirg County makes no representations or warranties, express or implied. as to accuracy, completeness, timeliness, or rights to the use of such ir:fomralion. This document is nat intended for use as a survey product. King County shall not be liable for any general, special, indirect, incidental, or consequential s County damages including, but not limited to, lost revenues or lost prohts resuiGrng from the use or misuse of the information contained on this map. Any safe of V'�� this map or information on this map is prohibOad except by written permission of King County. n Date: 10!1012013 Source: King County NAP - Hydrographic Information(http:lfwww.metrokc.govlGlSfik4AP) Legend i LOCM 100 Year Floodplain k-1 Lakes and Large Rivers Streams Incorporated Area King County Water Resource Inventory Areas 5 : 9tAkag uXnlsh (Cont) 1: snohomtsh 8: Cadz-SvnMaFnrsh 9: Dawarnimh -Gram 14: Puyallup -whoa 11 : Nrsqualty 12: C hantw-s C icmr i ne mro,"anon ,nCiudeo on this map has been Compiled by King County staff from a variety of sources and is subject in change without notice. Kirg County makes no representations or warranties, express or implied. as to accuracy, completeness, timeliness, or rights to the use of such ir:fomralion. This document is nat intended for use as a survey product. King County shall not be liable for any general, special, indirect, incidental, or consequential s County damages including, but not limited to, lost revenues or lost prohts resuiGrng from the use or misuse of the information contained on this map. Any safe of V'�� this map or information on this map is prohibOad except by written permission of King County. n Date: 10!1012013 Source: King County NAP - Hydrographic Information(http:lfwww.metrokc.govlGlSfik4AP) Figure S - Soil Survey yap tr� R I Project Location - Ap E� MF Soil Type RdC -F e.0 •_4 ud[ WoROC AOC AOa nU M M M Seo Ek A\.jy Mt Fits .. .. �� Tu 6rC w.F I Py HF � g�, M FYI - g AgOi ♦� .yv: Pv�•ih ARD AkF W % 'aP P M.0 • Mb Be Sk ACH , Ne M g M. yo w .g0 MR & r ry.__ ..�,r_........r. time AO e h _ ars ,wA Eu 3 AQO neo � R.iA w i ...A95 City of Renton Soil Survey Map ©uroundwalar PmeWmerea B --day Public Works Agjler Prorecdon A aq Zane 1 I Surface Water Utility �� 0 0.5 1 Q War Aotedon Area Zeno 1 A�dried G, Del Rosario _ 1-3 Renlon c [r �i 1212212009 �_'•• A Miles 1 �1 [Figure 9 - Drainage Complaints J N aoTH ST�! N 39TH l� S S.ESEI ° Sir N .38TH ST = sS 111N3<T,f Ne castle - ` SE PL E4 ■ ®R,N 3M Sr SE�,sTST:. N 3DT31 ST �� a 0 S� N 2FFW PL955 NE 27T" ST ' . O--684 res �sr �OLsz 4E2STMST t; JJ E 23RD AL N� z3RD p" 247TH .ST Seattle } Sr i ME22f,}ST NE 23TH ! u ? ' W NE VTH ST � Project Site - �— NE,mf"ST No Drainage Complaints NEITMSF a 1JTM pL hE ur ST s 7225 NE 12TM ST rPARK' v Tar" f a e 6779 x NE,I�TN ST ,,E ` to 1tT113 a �+`� _ c SII x ME 9r" Sr r z a0 ii, +l19 Nlk N STN ST Z L7 m Renton 2 W7TH Sr * m = AN6 � ME OT" CT Z. g NE STh ST H KITH ST NE 4TH ST p�04420 NEdiHSf 9 N 3fi0 ST , NE 3RD CT y v 2410 ST NSC -SROM ►F 24C lo- - S Tq@tN ST S) m N NE 2*t; ST C; Legend ;f County Boundary King County Water Resource g 1NO ST f Inventory Areas C� x Mountain Peaks F� S 3it] ST i 5= Drainage Studies �King County Drainage Basins x n 5 Neighborhood Drainage ,I Incorporated Area ti 5 at3t 5T Projects 1" Streets P� S SrH ST Z u * Regional Stormwater Facilities Niollth ay Residential Stormwater Annnas cn Facilities SW !TH ST U Commercial Stormwater Lakes and Large Rivers cilities s CP�Y Py Highways shwa Streams g ys Drainage Complaints iC 12008 King County 51,47, ~ � � 2 541 ft The trtfonnation included on this map has been compiled by King County staff from a variety of sources and is subject to charge without notice. King Ceunty makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such inforrnalion. This document is not intended for use as a survey product. King County shall not be liable for any general.. special, indirect, incidental, or consequential damages including, but no E limited lo, lost revenues or lost profits resulting from the use or misuse of the information contained on this map. Any sale of King County this map or information on this map is prohibited except by written permission of King County. Date: 10/1012013 Source: King County MAP - Stomnvater(http-l/wvrw.metrokc.govlGlSfiMAP) /e/ County Boundary X Mountain Peaks Drainage Studies Neighborhood Drainage Projects Regional Stormwater Facilities Residential Stormwater Facilities Commercial Stormwater Facilities Highways WAP Legend C3King County Water Resource Inventory Areas ❑ King County Drainage Basins f Incorporated Area Streets 11 rg h -way A nOrtafT Local Lakes and Large Rivers Streams Drainage Complaints 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 inlomration. This document is not intended for use as a survey product. King County shall not the liable for any general, special, indirect, incidental, or consequential LQ A 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 ��County V n# this map or information on this map is prohibited except try written permission of King County. Date:1011A72013 Sourre:KingCountyNAP-Stomwater(htlpJ/www.metrokc.gov/GlS/iMAP) 111. OFF-SITE ANALYSIS Task 1 - Study Area Definition and Maps The Renton drainage basin map was used to verify that the site was fully in the Lake Washington East drainage basin (See Figure 5 - Drainage Basin Map). Task 2 - Resource Review a) Adopted Basin Plans b) Floodplain/floodway (FEMA) Maps c) Off-site Analysis Reports d) Sensitive Areas Folio e) Drainage Complaints and Studies f) Road Drainage Problems g) King County Soils Survey: h) Wetland Inventory Maps: i) Migrating Rivers Study j) DOE's Section 303d List of Polluted Waters k) KC Designated Water Quality Problems 1) City of Renton critical maps: Task 3 - Field Inspection Lake Washington East Drainage Basin Site is not located in the floodplain (See Figure 7) N/A See Figures 7 - King County iMAP See Figure 9 N/A See Figure 8 - City of Renton Soil Survey Map No Wetlands N/A No WQ Problems No Critical Areas Site visits have been made to gather information including an analysis of the discharge from the site. Please refer to Task 4, Downstream Analysis below for more information. Task 4 - Drainage System Description and Problem Descriptions Runoff from the site will be conveyed to two existing storm systems. The majority of the site will tie into the 12" storm pipe that runs north/west on Sunset Boulevard NE. The remaining roof runoff will by conveyed to the existing 6" system on NE 10th Street via a new area drain at the northern corner of the project site. A catch basin will be added to the drainage system to tie in runoff from the site. Both drainage systems are directed to Lake Washington via John's Creek There are no existing drainage complaints or additional drainage problems as the site. Upstream Analysis The site is within the Lake Washington East drainage basin. No known drainage enters the site from upstream. Downstream Analysis The existing site discharges to existing catch basins located in NE 101h Street and Sunset Boulevard NE. These storm systems run west/north to NE Park Drive, where the stormwater discharge continues in a closed conveyance system until NE Park Drive reaches Lake Washington Boulevard N, and discharge into John's Creek, which then discharges into Lake Washington through Gene Coulon Park. No known drainage complaints are within a quarter -mile of the site (see Figure 9- Drainage Complaints Map). The storm system is part of the Lake Washington East drainage basin. Task 5 - Mitigation of Existing or Potential Problems COUGH LINPORTERLUNDEE N Renton Highlands Library 4 Renton, Washington There are no known problems drainage complaints downstream of the site (See Figure 9). No mitigation is proposed- COUGHLINPORTERLUNDEEN Renton Highlands Library 5 Renton, Washington IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Existing Site Hydrology (Part A) The existing site totals 0.369 acres and consists of an existing two story apartment building and a parking lot. The site slopes in a westerly direction with drainage described in Section IIT Downstream Analysis. These conditions are summarized in Table 1 below. Table I - Existing Site Conditions Area Breakdown Land Cover Area Description Impervious Area 0.209 acres Building roof, parking lot, and concrete walkways Pervious& Landscape 0.160 acres Associated landscaping Total Project Area 0.369 acres Total site area Percentage of Impervious Area 57% Developed Site Hydrology (Part B) The developed site hydrology will increase the amount of impervious area by 0.142 acres. A summary of the basin information is shown in Table 2. Table 2 - Developed Site Conditions Area Breakdown Land Cover Area Description Impervious Area 0.351 acres Building roof, walkways and 50% of roof area contributing to rain garden (as modeled) Rain garden pervious area (This area is Rain Garden Planter (R.G.) 0.0032 acres; included in the impervious/ pervious sections and does not count towards the total) Modeled as 50% Impervious, 50% Pervious, Contributing roof area to R.G. (RGx4) 0.130 acres (included in the impervious/ pervious sections, and does not count towards the total) Pervious& Landscape 0.018 acres Associated landscaping and 50% of roof area contributing to rain garden (as modeled) Total Project Area 0.369 acres Total site area Percentage of Impervious Area 95.1% Performance Standards and Flow Control System (Parts C and D) Per Figure 6, the site is governed by Peak Rate flow Control Standards. The site meets exception #1 on page 1- 34 of the City of Renton Amendments to the 2009 KCSWDM. Therefore, detention for this site is not required, COUGHLINPORTERLUNDEEN Renton Highlands Library 6 Renton, Washington as the threshold discharge area in which target surfaces subject to flow control for this site will not generate more than a 0.1-cfs increase in the existing site conditions 100 -year peak flow (See Figure 10-- KCRTS Peak Flow Calculations), Water Quality System (Part E) Standard Requirements Under core requirement #S of the 2009 KCSWMM, a project must add or replace over 5000 square feet of Pollution Generating Impervious Surface (PCIS) before water quality treatment is required. Because the site's total of added or replaced PCIS is less than 5,000 square feet, the site is exempt from providing water quality for the proposed redevelopment, COUGHLINPORTERLUNGEEN Renton Highlands Library 7 Renton, Washington COUGHLIN PORTERLU N DEEM Figure 10- KCRTS Peak Flow Calculations Renton Highlands Library- Detention Study: 11-11-2013 KCRTS SETUP: Time Series Information: Sea -Tac, Scale=1.0, Time Step=15-minute, Data Type=Reduced Existing Till Grass=0.160 acres Impervious=0.209 acres TOTAL=0.369 acres ProposedRG (Rain Garden) Till Grass=0.01 S acres Impervious=0.351 acres TOTAL=0.369 acres Peak Flows: Flow Frequency Analysis Time Series File:existing.taf Project Location:Sea-Tac ---Annual Peak Flow Rates --- Flow Rate Rank Time of Peak (CFS) 0.100 6 8/27/01 18:00 0.073 8 1/05/02 15:00 0.223 2 12/08/02 17.15 0.080 7 8/23/04 14:30 0.135 4 11/17/04 5:00 0.122 5 10/27/05 10:45 0.140 3 10/25/06 22:45 0 327 1 1/09/08 6:30 Computed Peaks Flow Frequency Analysis -------------------- Time Series File,proposedrg tsf Project Location Sea -Tao ---Annual Peak Flog Rates--- Flov Rate Rank Time of Peak (CFS) 0.167 6 8/27/01 18:00 0.117 8 9/17/02 17:45 0 320 2 12/08/02 17:15 6.134 7 8/23/04 14:30 0.178 5 10/28/04 16:00 0,188 4 10/27/05 10:45 0.228 3 10/25/06 22:45 0.423 1 1/09/08 6:30 Computed Peaks Flov Frequency Analysis - - Peaks - - Rank Return Prob (CFS) Period 0.327 1 100.00 0.990 0.223 2 25.00 0.960 0.140 3 10.00 0.900 0.135 4 5.00 0.800 0.122 5 3.00 0.667 0.100 6 2.00 0.500 0.080 7 1.30 0.231 0.073 8 1.10 0.091 13.293 50.00 0.980 Flow Frequency Analysis------- - - Peaks - - Rank Return Prob (CFS) Period 0.423 1 100.00 0.990 0.320 2 25.00 0.960 0.220 3 10.00 0.900 0.188 4 5.00 0.800 0.178 5 3.00 0.667 0.167 6 2.00 0.500 0.134 7 1.30 0.231 0.117 8 1.10 0.091 0.389 50.00 0.980 Conclusions: Existing Q106-0.327 o Q100p,ap4wd(0.423) - Q1ooEX;s1;r)g(0.327)=0.096 <0.1 cfs Proposed Q,00=0.423 Therefore, Detention is not required since the 100 -year peak flow rate for the proposed condition is less than a 0.1 cfs increase from the existing 100 -year peak flow rate. V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN This section discusses the criteria that will be used to analyze and design the proposed storm conveyance system. Standard Requirements (based on KCSWDM and SAO): 1. Facilities must convey the 100 -year flow without overtopping the crown of the roadway, flooding buildings, and if sheet flow occurs it must pass through a drainage easement. The existing drainage facilities are not being altered and have no ]mown overtopping issues. See Figure 9. 2. New pipe systems and culverts must convey the 25 -year flow "that least 0.5 feet of freeboard. (1.2.4-1). The new pipe systems will be designed to convey the 25 -year flow with at least 0.5 feet of freeboard. 3. Bridges must convey the 100 -year flow and provide a minimum of two feet, varying tip to six feet, of clearance based on 25% of the mean channel width. (1.2.4-2)(4.3.5-6). N/A. This project does not propose a bridge. 4. Drainage ditches roust convey the 25 -year flow with 0.5 feet of freeboard and the 100 -year flow without overtopping. (1.2.4-2). N/A This project does not propose a drainage ditch. 5. Floodplain Crossings must not increase the base flood elevation by more than 0.01 feet [4103.01 and shall not reduce the flood storage volume [37(82.A)1. Piers shall not be constructed in the FEMA floodway. [41(83.F.1)]. No work is being proposed within the base flood elevation or within the FEMA floodway. 6. Stream Crossings shall require a bridge far class 1 streams that does not disturb or banks. For type 2 and type 3 steams, open bottom culverts or other method may be used that will not harm the stream or inhibit fish passage. [60(95.B)1. There are no new stream (river) crossings associated with the construction of this project. 7. Discharge at natural location is required and roust produce no significant impacts to the downstream property (1.21-1). The project will discharge to the existing storm systems in NE 10th Street and Sunset Boulevard NE. On-site Conveyance Existing Conditions: Runoff from the existing site is directed to the existing storm drainage systems located in Sunset Boulevard NE_ Developed Storm system description: There will be roof drains connecting out to the existing public storm system in Sunset Boulevard NE. There will also be an underdrain in the rain garden planter that has a storm pipe leading to an area drain on-site, which then leads out to the existing public storm system in NE 10th Street. A small portion of the site and the entry canopy discharges to the existing conveyance system in NE 101h Street. Footing drains and shoring wall drains will be included and will require a sump pump, which will be located within the garage and designed by the plumbing engineer. COUGHLINPORTERLUNDEEN Renton Highlands Library 8 Renton, Washington VI. SPECIAL REPORTS AND STUDIES Geotechnical Engineering Study: Proposed Mixed -Use Development Renton, Washington, Prepared by Geotech Consultants, Inc. on April 18, 2013. Not included at this time. COUGHLINPORTERLUNQEEN Kenton Highlands Library 9 Renton, Washington VII. OTHER PERMITS This project will require building and demolition permits from the City of Renton and a CSWPPP, See Section & for the CSWPPP (not included at this time). COUGHLINPORTERLUNDEEN Renton Highlands Library 10 Renton, Washington VIII. CSWPPP ANALYSIS AND DESIGN This section lists the requirements that will be used when designing the TESC plan For this site. A copy of the Draft CSWPPP has not been included at this time as the CSWPPP will be finalized after a contractor is brought on board. A draft CSWPPP will be provided before permit is issued. Standard Requirements Erosion/Sedimentation Plan shall include the following- 1. ollowing 1. Facilities required include. Catch basin filter socks. (1.2.5-1). The project will provide sediment protection at the existing catch basins and maintain existing hardscape areas until areas will be re -paved 2. Timing - For the period between November 1 through March 1 disturbed areas greater than 5,000 square feet left undisturbed for more than 12 hours must be covered with mulch, sodding, or plastic covering. A construction phasing plan shall be provided to ensure that erosion control measures are installed prior to clearing and grading. (1.2.5-1). Notes addressing each of these items have been placed on the civil engineering plans. 3. Planning - Plan shall limit tributary drainage to an area to be cleared and graded. Delineate dimension, stake and flag clearing limits (1.2.5-1). The clearing limits have been indicated on the TESL plan. Notes addressing this item have been placed on the civil engineering plans. 4. Revegetation - Revegetate areas to be cleared as soon as practicable after grading. (1.2.5-1). Notes addressing this item have been placed on the civil engineering plans. COUGHLINPORTERLUNDEEN Renton Highlands Library 11 Renton, Washington IX. BOND QUANTITY, FACILITY SUMMARIES, AND DECLARATION OF COVENANT A Bond Quantity Worksheet is not included at this time. A Facilities Summaries Sheet has not been included in this section because there are no water quality or flow control devices being installed as part of this project. A Declaration of Covenant has not been included in this section because there are no water quality or flow control devices being installed as part of this project. COUGHLINPORTERLUNDEEN Renton Highlands Library 12 Renton, Washington X. OPERATION AND MAINTENANCE MANUAL Standard Maintenance Per standards set forth in the King County Surface Water Design Manual, the owner will maintain facilities. Sections of the King County Storm Water Management Design Manual outlining the Operations and Maintenance of these facilities are not included at this time, but will be as the project progresses. COUGHLINPORTERLUNUEEN Renton I lighlands Library 13 Renton, Washington MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES AT PUGET SOUND SKILLS CENTER NO. 1- RAIN GARDENS Maintenance Defect Conditions When Maintenance Results Expected When Component Is Needed Maintenance Is Performed General Trash & Any trash and debris which exceed 1 Trash and debris cleared Debris cubic foot per 1,000 square feet (this is from site. 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. Poisonous Any poisonous or nuisance vegetation No danger of poisonous Vegetation which may constitute a hazard to vegetation where County County personnel or the public. personnel or the public might normally be. (Coordination with Seattle -King County Health Department) Pollution Oil, gasoline, or other contaminants of No contaminants present one gallon or more or any amount other than a surface film. found that could. 1) cause damage to (Coordination with plant, animal, or marine life; Seattle/ King County 2) constitute a fire hazard; or 3) be Health Department) flushed downstream during rain storms. Unmowed if facility is located in private residential When mowing is needed, Grass/ area, mowing is needed when grass grass/ ground cover Ground exceeds 18 inches in height. In other should be mowed to 2 Cover areas, the general policy is to make the inches in height. Mowing pond site match adjacent ground cover of selected higher use and terrain as long as there is no areas rather than the entire interference with the function of the slope may be acceptable facility. for some situations. Rodent Any evidence of rodent holes if facility Rodents destroyed and Holes is acting as a dam or berm, or any dam or berm repaired. evidence of water piping through dam (Coordination with or berm via rodent holes. Seattle/King County Health Department) Insects When insects such as wasps and Insects destroyed or hornets interfere with maintenance removed from site. activities. Tree Tree growth does not allow Trees do not hinder Growth maintenance access or interferes with maintenance activities. maintenance activity (i.e., slope Selectively cultivate trees mowing, silt removal, vactoring, or such as alders for equipment movements). If trees are not firewood_ COUGHLINPORTERLUNDEEN Renton Highlands Library 14 Renton, Washington Side Slopes of facility Storage Area interfering with access, leave trees alone. Erosion Eroded damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. Sediment Accumulated sediment that exceeds 10% of the designed pond depth. SIopes should be stabilized by using appropriate erosion control measure(s); e.g., rock reinforcement, planting of grass, compaction. Sediment cleaned out to designed pond shape and depth; pond reseeded if necessary to control erosion. Emergency Rock Only one Iayer of rock exists above Replace rocks to design Overflow/Spil Missing native soil in area five square feet or standards. lway larger, or any exposure of native soil at the top of out flow path of spillway. Rip -rap on inside slopes need not be replaced. Note: Sediment accumulation of more than ,25 inches per year may indicate excessive erosion is occurring upstream of the facility or that conveyance systems are not being properly maintained. The contributing drainage area should be checked for erosion problems or inadequate maintenance of conveyance systems if excessive sedimentation is noted in an infiltration facility. Check twice a year during first 2 years of operation; once a year thereafter. Clean manholes catch basins, repair damaged inlets/outlets, clean trash racks. NO.2 - CLOSED DETENTION SYSTEMS (VAULTS) Maintenance Defect Conditions When Maintenance is Results Expected When Component Needed Maintenance is Performed Storage Area Plugged Air One-half of the cross section of a vent is Vents free of debris and Vents blocked at any point with debris and sediment sediment Debris and Accumulated sediment depth exceeds Sediment 10% of the diameter of the storage area for 1/2 length of storage vault or any point depth exceeds 15% of diameter. Example: 72 -inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than 1/2 length of tank. All sediment and debris removed from storage area. Manhole Cover Not in Cover is missing or only partially in Manhole is closed. Place place. Any open manhole requires maintenance. COUGH LINPORTERLUNDEEN Renton Highlands Library 15 Renton, Washington Locking Mechanism cannot be opened by one Mechanism opens with Mechanism maintenance person with proper tools. proper tools. Not Working Bolts into frame have less than 1/2 inch of thread (may not apply to self-Iocking lids.) Cover One maintenance person cannot remove Cover can be removed Difficult to lid after applying 801bs of lift. Intent is to and reinstalled by one Remove keep cover from sealing off access to maintenance person. maintenance. Ladder Rungs King County Safety Office and/or Ladder meets design Unsafe maintenance person judges that ladder is standards allows unsafe due to missing rungs, maintenance person safe misalignment, rust, or cracks. access. Catch Basins See "Catch Basins' Standards No. 4 See "Catch Basins" Standards No. 4 NO.3 - CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect Condition When Maintenance is Results Expected When Component Needed Maintenance is Performed General "Trash and Distance between debris build-up and All trash and debris Debris bottom of orifice plate is less than 1-1/2 removed. (Includes feet. Sediment) Structural Structure is not securely attached to Structure securely Damage manhole wall and outlet pipe structure attached to wall and should support at least 1,000 Ibs of up or outlet pipe. down pressure. Structure is not in upright position (allow Structure in correct up to 10% from plumb). position. Connections to outlet pipe are not Connections to outlet watertight and show signs of rust. pipe are water tight; structure repaired or replaced and works as designed. Any holes --other than designed holes --in Structure has no holes the structure, other than designed holes. Cleanout Gate Damaged or Cleanout gate is not watertight or is Gate is watertight and Missing missing. works as designed. Maintenance Defect Conditions When Maintenance is Results Expected When Component Needed Maintenance is performed COUGHLINPORTERLUNDEEN Renton Highlands Library 16 Renton, Washington Gate cannot be moved up and down by Gate moves up and one maintenance person. down easily and is watertight. Chain leading to gate is missing or Chain is in place and damaged. works as designed. Trash or debris in any inlet or outlet pipe lniet and outlet pipes blocking more than 1/3 of its height. free of trash or debris. Dead animals or vegetation that could No dead animals or generate odors that could cause vegetation present complaints or dangerous gases (e.g., within the catch basin. methane). COUGHLINPORTERLUNDEEN Renton Highlands Library 17 Renton, Washington Gate is rusted over 50% of its surface Gate is repaired or area, replaced to meet design standards.. Orifice Plate Damaged or Control device is not working properly Plate is in place and Missing due to missing, out of place, or bent works as designed. orifice plate. Obstructions Any trash, debris, sediment, or vegetation Plate is free of all blocking the plate. obstructions and works as designed. Overflow Pipe Obstructions Any trash or debris blocking (or having Pipe is free of all the potential of blocking) the overflow obstructions and works pipe• as designed. Manhole See "Closed Detention Systems" See "Closed Detention Standards No. 2 Systems' Standards No. 2 Catch Basin See "Catch Basins" Standards No. 4 See `Catch Basins" Standards No. 4 NO.4 - CATCH BASINS Maintenance Defect Conditions When Maintenance is Results Expected When Component Needed Maintenance is performed General Trash & Trash or debris of more than 1/2 cubic No Trash or debris Debris foot which is located immediately in front located immediately in (Includes of the catch basin opening or is blocking front of catch basin Sediment) capacity of the basin by more than 10% opening. Trash or debris (in the basin) that exceeds No trash or debris in the 1/3 the depth from the bottom of basin to catch basin. invert the lowest pipe into or out of the basin. Trash or debris in any inlet or outlet pipe lniet and outlet pipes blocking more than 1/3 of its height. free of trash or debris. Dead animals or vegetation that could No dead animals or generate odors that could cause vegetation present complaints or dangerous gases (e.g., within the catch basin. methane). COUGHLINPORTERLUNDEEN Renton Highlands Library 17 Renton, Washington Deposits of garbage exceeding 1 cubic foot in volume Structure Corner of frame extends more than 3/4 Damage to inch past curb face into the street (If Frame and/or applicable). Top Slab Top slab has holes larger than 2 square inches or cracks wider than 1/4 inch (intent is to make sure all material is running into basin). Frame not sitting flush on top slab, i.e., separation of more than 3/4 inch of the frame from the top slab. NO.4 - CATCH BASINS (CON77NUED) No condition present which would attract or support the breeding of insects or rodents. Frame is even with curb. Top slab is free of holes and cracks. Frame is sitting flush on top slab. Maintenance Defect Condition When Maintenance is Results Expected Components Needed When Maintenance is Performed. Cracks in Basin Cracks wider than 1/2 inch and longer Basin replaced or Walls/ Bottom than 3 feet, any evidence of soil particles repaired to design entering catch basin through cracks, or standards. maintenance person judges that structure is unsound. Cracks wider than 1/2 inch and longer than 1 foot at the joint of any inlet/ outlet pipe or any evidence of soil particles entering catch basin through cracks. Sediment/ Basin has settled more than 1 inch or Misalignment has rotated more than 2 inches out of alignment. Fire Hazard Vegetation Pollution Presence of chemicals such as natural gas, oil and gasoline. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Basin replaced or repaired to design standards. No flammable chemicals present. Vegetation growing across and blocking No vegetation blocking more than 10% of the basin opening. opening to basin. Vegetation growing in inlet/outlet pipe No vegetation or root joints that is more than six inches tall growth present, and less than six inches apart. Nonflammable chemicals of more than No pollution present 1/2 cubic foot per three feet of basin other than surface film. Iength. COUGHLINPORTERLUNDEEN Renton Highlands Library 18 Renton, Washington Catch Basin Cover Not in Cover is missing or only partially in Catch basin cover is Cover Place place_ Any open catch basin requires closed maintenance. Locking Mechanism cannot be opened by on Mechanism opens with Mechanism maintenance person with proper tools. proper tools. Not Working Bolts into frame have less than 1/2 inch of thread, Cover Difficult One maintenance person cannot Cover can be removed to Remove remove lid after applying 80 lbs. of lift; by one maintenance intent is keep cover from sealing off person. access to maintenance, Ladder Ladder Rungs Ladder is unsafe due to missing rungs, Unsafe misalignment, rust, cracks, or sharp edges. Metal Grates Grate with opening wider than 7/8 (If Applicable) inch. Trash and Trash and debris that is blocking more Debris than 20% of grate surface. Damaged or Grate missing or broken member(s) of Missing. the grate. NO.5 DEBRIS BARRIERS (E.G., TRASH RACKS) Maintenance Defect Condition When Maintenance is Components Needed General Trash and Debris Metal Damaged/ Missing Bars. COUGHLINPORTERLUNDEEN Ladder meets design standards and allows maintenance person safe access. Grate opening meets design standards. Grate free of trash and debris. Grate is in place and meets design standards. Results Expected When Maintenance is Performed. Trash or debris that is plugging more Barrier clear to receive than 20% of the openings in the barrier. capacity flow. Bars are bent out of shape more than 3 inches. Bars are missing or entire barrier missing. Bars in place with no bends more than 3/4 inch. Bars in place according to design. Bars are loose and rust is causing 50`Yo Repair or replace barrier deterioration to any part of barrier. to design standards. Renton Highlands Library 19 Renton, Washington NO.6 - ENERGY DISSIPATERS Any defect in the fence that permits Maintenance Defect Conditions When Maintenance is Results Expected When Components Erosion more than 4 inches high and Needed Maintenance is 12-18 inches wide permitting an fence that exceeds 4 Performed. Manhole/ Worn or Structure dissipating flow deteriorates Replace structure to Chamber Damaged Post. to 1/2 or original size or any design standards. Baffles, Side of concentrated worn spot exceeding one Chamber square foot which would make structure unsound. Other Defects See "Catch Basins" Standard No. 4 NO.7 - FENCING Maintenance Defect Components General Wire Fences Conditions When Maintenance is Needed See "Catch Basins" Standard No. 4 Results Expected When Maintenance is Performed Missing or Any defect in the fence that permits Parts in place to provide Broken Parts easy entry to a facility. adequate security. Erosion Erosion more than 4 inches high and No opening under the 12-18 inches wide permitting an fence that exceeds 4 opening under a fence. inches in height. Damaged Post out of plumb more than 6 inches. Post plumb to within 1 - Parts 1/2 inches. Deteriorated Paint or Protective Coating Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence (including post, top Fence is aligned and rails) more than 1 foot out of design meets design standards. alignment. Missing or Ioose tension wire. Extension arm missing, broken, or bent out of shape more than 11/2 inches. Part or parts that have a rusting or scaling condition that has affected structural adequacy. Tension wire in place and holding fabric. Extension arm in place with no bends larger than 3/4 inch_ Structurally adequate posts or parts with a uniform protective coating. COUGHLINPORTERLUNDEEN Renton Highlands Library 20 Renton, Washington NO.8 - GATES Maintenance Defect Conditions When Maintenance is Results Expected Component Needed When Maintenance is Performed General Damaged or Missing gate or locking devices. Gates and Locking Missing devices in place. Members Broken or missing hinges such that Hinges intact and gate cannot be easily opened and lubed. Gate is working closed by a maintenance person. freely_ Gate is out of plumb more than 6 Gate is aligned and inches and more than 1 foot out of vertical. design alignment. Missing stretcher bar, stretcher Stretcher bar, bands bands, and ties. and ties in place. Openings in See "Fencing" Standard No. 7 See "Fencing" Standard Fabric No. 7 NO.9 - CONVEYANCE SYSTEMS (PIPES & DITCHES) Maintenance Defect Conditions When Maintenance is Results Expected When Component Needed Maintenance is Performed Pipes Sediment & Accumulated sediment that exceeds Debris 20% of the diameter of the pipe. Vegetation Vegetation that reduces free movement of water through pipes. Damaged Protective coating is damaged; rust is causing more than 50% deterioration to any part of pipe. Any dent that decreases the cross section area of pipe by more than 20%. Pipe cleaned of all sediment and debris. All vegetation removed so water flows freely through pipes. Pipe repaired or replaced. Pipe repaired or replaced. Open Ditches Trash & Debris Trash and debris exceeds 1 cubic foot Trash and debris cleared per 1,000 square feet of ditch and from ditches. slopes_ Sediment Vegetation Accumulated sediment that exceeds 20 % of the design depth. Vegetation that reduces free movement of water through ditches. Ditch cleaned/ flushed of all sediment and debris so that it matches design. Water flows freely through ditches. COUGHLINPORTERLUNDEEN Renton Highlands Library 21 Renton, Washington Catch Basins Debris Barriers (e.g., Trash Rack) Erosion See "Rain gardens" Standard No_ 1 Damage to Slopes Rock Lining Maintenance person can see native Out of Place or soil beneath the rock lining. Missing (If Applicable). See "Catch Basins: Standard No. 4 See "Debris Barriers" Standard No.5 NO. 10 - GROUNDS (LANDSCAPING) Maintenance Defect Conditions When Maintenance is Component Needed See "Rain gardens" Standard No.1 Replace rocks to design standards. See "Catch Basins" Standard No. 4 See "Debris Barriers" Standard No. 5 Results Expected When Maintenance is Performed General Weeds Weeds growing in more than 20% of Weeds present in less (Nonpoisonous the landscaped area (trees and shrubs than 5% of the only). landscaped area. Safety Hazard Any presence of poison ivy or other No poisonous vegetation poisonous vegetation. present in landscaped area. Trash or Litter Paper, cans, bottles, totaling more than Area clear of litter. 1 cubic foot within a landscaped area (trees and shrubs only) of 1,000 square feet. Trees and Damaged Limbs or parts of trees or shrubs that Trees and shrubs with Shrubs are split or broken which affect more less than 5% of total than 25% of the total foliage of the tree foliage with split or or shrub. broken Iimbs. Trees or shrubs that have been blown down or knocked over. Trees or shrubs which are not adequately supported or are leaning over, causing exposure of the roots. Tree or shrub in place free of injury. Tree or shrub in place and adequately supported; remove any dead or diseased trees. COUGHLINPORTERLUNDEEN Renton Highlands Library 22 Renton, Washington I NO. 11 - ACCESS ROADS/ EASEMENTS Maintenance Defect Condition When Maintenance is Results Expected Component Needed When Maintenance is Performed General Trash and Trash and debris exceeds 1 cubic Roadway free of debris Debris foot per 1,000 square feet i.e., trash which could damage and debris would fill up one tires. standards size garbage can. Blocked Debris which could damage vehicle Roadway free of debris Roadway tires (glass or metal). which could damage tires. Any obstruction which reduces Roadway overhead clearance above road surface to less clear to 14 feet high. than 14 feet. Any obstruction restricting the Obstruction removed access to a 10 to 12 foot width for a to allow at least a 12 distance of more than 12 feet or any foot access. point restricting access to less than a 10 foot width. Road Surface Settlement, When any surface defect exceeds 6 Road surface Potholes, inches in depth and 6 square feet in uniformly smooth Mush Spots, area. In general, any surface defect with no evidence of Ruts which hinders or prevents settlement, potholes, maintenance access. mush spots, or ruts. Vegetation in Weeds growing in the road surface Road surface free of Road Surface that are more than 6 inches tall and weeds taller than 2 less than 6 inches tall and less than inches. 6 inches apart within a 400 -square foot area. COUG H LI N PORTERLUN DE E N 23 Renton Highlands Library Renton, Washington NO. 12- WATER QUALITY FACILITIES A.) Cartridge Filter Vault Maintenan Defect or Condition When Maintenance Recommended ce Problem is Needed Maintenance to Component Correct Problem Below Sediment Sediment depth exceeds 0.25- No sediment Ground Accumulati inches. deposits which Vault on on would impede Media. permeability of the compost media. Sediment Sediment depth exceeds 6- No sediment Accumulati inches in first chamber. deposits in vault on in Vault bottom of first chamber. Access Cover Damaged/ Not Working Cover cannot be opened, one person cannot open the cover, corrosion/ deformation of cover. Cover repaired to proper working specifications or replaced. COUG H LI NPORTERLUN b E EN Renton Highlands Library 24 Renton, Washington Trash/ Trash and debris accumulated Trash and debris Debris on compost filter bed. removed from the Accumulati compost filter bed. on Sediment in When drain pipes, clean -outs, Remove the Drain become full with sediment and/ accumulated Pipes/Clean or debris. material from the -Outs facilities. Below Compost Drawdown of water through Replace media Ground Media the media takes Ionger than 1 cartridges. Cartridge hour, and/ or overflow occurs type frequently. Short Flows do not properly enter Replace filter Circuiting filter cartridges. cartridges. Damaged Any part of the pipes that are Pipe repaired and/ Pipes crushed, damaged due to or replaced. corrosion and/ or settlement. Access Cover Damaged/ Not Working Cover cannot be opened, one person cannot open the cover, corrosion/ deformation of cover. Cover repaired to proper working specifications or replaced. COUG H LI NPORTERLUN b E EN Renton Highlands Library 24 Renton, Washington Vault Cracks wider than 1/2 -inch and Vault replaced or Structure any evidence of soil particles repaired to design Includes entering the structure through specifications. Cracks in the cracks, or maintenance/ Wall, inspection personnel determines Bottom, that the vault is not structurally Damage to sound. Frame and/ or Top Slab Cracks wider than 1/2 -inch at No cracks more than the joint of any inlet/ outlet pipe 1/4 -inch wide at the or any evidence of soil particles joint of the inlet/ entering the vault through the outlet pipe. walls. Baffles Baffles corroding, cracking Repair or replace warping, and/ or showing signs baffles to of failure as determined by specification. maintenance/ inspection person. Access Ladder is corroded or Ladder replaced or Ladder deteriorated, not functioning repaired and meets Damaged properly, missing rungs, cracks, specifications, and is and misaligned. safe to use as determined by inspection personnel. COUGHUNPORTERLUNDEEN Renton Highlands Library 25 Renton, Washington