Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Home
My WebLink
About
LUA-08-118_Misc
"" " ,,., ;,·- • 1;>. [' "'"' ~ :,,__..,, ~ '"" ~ ~ ' ·~ 008700 AKER'S R NO. 5 ,, . -.,.," '''" ,, ~ 008700 ' :f=C.SP 560025. ,.,., . LOT X ,_, .. •·'"'" 2~ ~ ~ 8€03310570 -JI, '"" oc,,,· ·,:;; "'"'';, ' '.'" ·-1.'J,· -/. ' .. ' . , ·,w f ,,,,·Ju;. ;J " "l " :: ,\ ''.:".''.f , , ·L: _llL -'-"'·····--· , -'>111111-,.,,~;J11(,, _. --- J ' I :,; ,l ·'"· '" 326115 HERO'' GLEr, ::;)ND0 . •_ r -,, 162680 #21,1 LJ CLIFF( RD'S 1ST ' I; I ,.·u. '.l'··· "·' 353010 HUNTINGTON HEK>HTS CONOO ..,_,.,..,,:-,_"'"""'" KCLLA # 890~032 .--.-- .,,,,- ,·,.:,···-· ,,,,.,,,,-.,• "' o,,·--· ·,:,·· ,, > •,•,-, i, ""-" . ' . . . : lc)•1 ;' ;:'. KC: sP 11&1W1 -MO ' '" . • " § l-1<1', . "'"' >.::;, ''" "''" "''· , I N . ' 0 ,oo /11 ,._ J. oo' ~-,,. b 9C.' "' ,, DRAFT TECHNICAL INFORMATION REPORT MEYER SHORT PLAT SE 173RD STREET , WA 98055 ( -\ -('.""'\. \ \ \ -. The Concept Group 650 South Orcas St, Suite 214 • Seattle, WA 98168 • (206) 658-0125 Land De v elopment & Civil Engineering Consultants DRAFT TECHNICAL INFORMATION REPORT MEYER TOWNHOMES SHORT PLAT 10839 SE 173RD STREET RENTON, WA 98055 September 2008 I cert ify that this technical information report and all attachments were prepared either by me or my technical stqff working directly under my supervision. EXPIRES 09/13/09 T HE CONCE PT GROUP Table of Contents ACRONYM TERMINOLOGY .................................................................................................................................... I SECTION 1: PROJECT OVERVIEW ......................................................................................................................... 1 SITE INFORMATION ............................................................................................................................................ 1 DRAINAGE BASIN .............................................................................................................................................. 1 SOILS INFORMATION............................ . ................................................................................................... 1 SECTION 2: CONDITIONS AND REQUIREMENTS .................................................................................................... 2 EXISTING SITE HYDROLOGY.................. . ............................................................................................... 2 DEVELOPED SITE HYDROLOGY ........................................................................................................................ 2 DESIGN REQUIREMENTS................... . .......................................................................................... 2 SECTION 3: LEVEL 1 0FFSITE ANALYSIS .............................................................................................................. 2 DOWNSTREAM ANALYSIS................. . ................................................................................................. 2 DISCHARGE AT NATURAL (EXISTING) LOCATION .............................................................................................. 2 SECTION 4: FLOW CONTROL/ WATER QUAI.ITY ANALYSIS & DESIGN •.•......................••.•.••.••.••.........••.••.••...••.• 3 FLOW CONTROL ................................................................................................................................................ 3 DRAINAGE ANALYSIS (KCRTS)....... . .......................................................................................... 3 INFILTRATION FACILITY DESIGN....... . ............................................................................................... 3 WATER QUALITY .............................................................................................................................................. .4 SECTION 5: CONVEYANCE SYSTEM ....................................................................................................................... 4 100-YEAR FLOOD/OVERFLOW CONDIT[ON ....................................................................................................... .4 SECTION 6: SPECIAL REPORTS AND Sn;DIES ....................................................................................................... 4 SECTION 7: OTHER PERMITS .•.••.••.••••..........................•...••.••.••.••.•..•....••.••.••.••.•.••.••..•..........................••.•........•.••. 4 SECTION 8: CSWPP (EROSION CONTROL) ANALYSIS AND DESIGN .................................................................... 4 CONSTRUCTION SEQUENCE AND PROCEDURE .................................................................................................... 5 TRAPPING SEDIMENT .......................................................................................................................................... 5 SECTION 9: BOND QUANTITIES AND DECLARA TJONS OF COVENANTS .....................•.••.••.••.•..•.••.••.••.••.•.••.••.••.•.••. 6 SECTION 10: OPERATIONS AND MAINTENANCE ................................••.••.•..•.••.••.•..••.•..•.••.••.•.....•..•.••.••.•.••..•......... 6 Appendices Appendix A: Vicinity Map, Site Photos and Property Information Appendix B: Soils Information Appendix C: Proposed Drainage Plan Appendix D: Flow Control, Water Quality and Infiltration Design Appendix E: Erosion Control Plans Appendix F: Maintenance Procedures ACRONYM TERMINOLOGY ,, Inch cf Cubic Feet cfs Cubic Feet per Second CMP Corrugated Metal Pipe DI Ductile Iron HOPE High Density Polyvinyl Ethane JUD Joint Use Driveway KCSWM King County Surface Water Manual PGIS Pollution Generali ng Impervious Surface PVC Polvvinvl Chloride RCP Reinforced Concrete Pipe scs Soils Service Conservation Sq Ft Sauare foot General Notes: 1. The information contained in this report is based on a topography and boundary survey prepared by Dryco Surveying, Inc., the King County Assessor's map, and on-site observations and measurements. If any changes are made to these drawings or the site that will affect the calculations in this report, the engineer shall be notified. All construction based on this report shal I be stopped and sh al I not proceed until the impact of the changes can be reflected in a supplement report. 2. This report is based on limited subsurface exploration. During construction, if soils conditions are found that are significantly different from those identified in this report, construction should stop until those items affected by the changed conditions can be identified and adjusted, if needed to reflect the changed conditions. 3. This report is prepared for the sole use of client for the purpose of subdividing the property located at 10839 SE 173'd Street; Renton, WA 98055. All other uses are expressly prohibited without prior written approval from the engineer. 4. All construction related to the drainage system for this project will be in accordance with the 1990 King County Surface Water Design Manual and the City of Renton current standards unless specifically mentioned in this report and/or approved by the City of Renton. Meyer Town homes Short Plat -DRAFT Technical Information Report September 2008 SECTION 1: PROJECT OVERVIEW The property is located at 10839 SE 1 73'd Street in the City of Renton, Washington. The property has one (1) single family residence. The project proposes to short plat the existing parcel into three (3) single family residential lots. Proposed improvements include the construction of an attached two-unit townhouse, a Private Access/Utility tract, associated uti Ii ties and stormwater management facilities and the relocation of the existing house. Site Information Refer to Appendix A for the Vicinity Map and site photos of this project. Location: 10839 SE 173'd Street; Renton, Washington 98055 Section/Township/Range: SW 14 of SE 14 Sec. 29, T.23N, R.4E of W.M. Size: 12,722 sq ft (approximately 0.29 acre) City, County, State: Renton, King County, Washington Governing Agency: City of Renton Design Criteria: 1990 King County Surface Water Manual Water and Sewer District: Soos Creek Water & Sewer District Drainage Basin The entire property drains to one basin with a contributing area of 0.29 acres. The general topography of the site slopes from southeast to northwest. Elevations on the site vary from a high point of 420 feet at the northern property line to 412 feet at the southern property line, with grades varying from 1.0% to 8.0%. Soils Information Soils Survey The Soil Survey prepared by the United States Department of Agriculture Natural Resource Conservation Service, indicates the soil type within the project as AmC (Alderwood material), SCS Hydrologic Soil Group C. This Alderwood soil series contains moderately well drained soils consisting predominately of Alderwood material with slopes between six (6) to fifteen (15) percent. Runoff and erosion hazards from this soil type is medium. This series of soil is suitable for urban development.The KCRTS equivalent soils group, as defined in Table 3.2.2.B of the 2005 King County Surface Water Manual (KCSWM), is Till. Refer to Appendix B for the Soils Survey Map & sieve analysis. The Concept Group Page I Meyer Townhomes Short Plat -DRAFT Technical Information Report SECTION 2: CONDITIONS AND REQUIREMENTS Existing Site Hydrology September 2008 The site is currently developed with one single-family residence. The general topography slopes from southeast to northwest. Stormwater runoff presently infiltrates to native soils. During heavy rainfall events, stormwater sheet flows towards SE 173'd Street into the system of grass-lined ditches and driveway culverts. Developed Site Hydrology The project proposes to short plat the existing parcel into three (3) single family residential lots. Each of the new residential lots will consist of a total of approximately 1,400 sq ft to 2,000 sq ft of new impervious surface with the remainder of the lots consisting of landscape and lawns. Stormwater for the roof, driveway and Private Access Tract will be infiltrated to native soils. Refer to the Drainage Plan in Appendix C for the proposed storm drainage design. Design Requirements The 1990 King County Surface Water Manual sets forth the drainage requirements for this project. The drainage requirements are summarized in Table 1. Table 1 -Jurisdictional Reauirements Peak Run-off Control: NIA -based on 0.5 els exemption Water Qua I ity: NIA -based on surface area exemption Conveyance: 25-year developed flow Downstream Analysis: Level 1 SECTION 3: LEVEL 1 0FFSITE ANALYSIS Downstream Analysis Stormwater runoff presently infiltrates to native soils. During heavy rainfall events, Stormwater runoff is conveyed in a series of grass-lined ditches and 12-inch driveway culverts along SE 173'd Street. Stormwater continues to flow west towards 1 OB'h Way SE where it discharges to a large wetland via a 36-inch culvert under 108'h Way SE. There is no sign of erosion within a quarter mile of the project. Discharge at Natural (Existing) Location Stormwater presently infiltrations to native soils. During heavy rainfall events, stormwater may sheet flow to the ditches along SE 173'd Street. The Concept Group Page 2 Meyer Townhomes Short Plat -DRAFT Technical Information Report SECTION 4: FLOW CONTROL/ WATER QUALITY ANALYSIS & DESIGN Flow Control September 2008 This project will create approximately 8,142 square feet of new impervious surface. Flow control facilities are not required because the project creates less than 0.50 cfs increase in discharge from the existing condition for the 100-year storm event per the KCRTS data below. Refer to Appendix D for flow control calculations. Drainage Analysis (KCRTS) The King County Runoff Time Series (KCRTS) Hydrologic Model is the required methodology under the 1990 King County Surface Water Design Manual for sizing detention facilities. The project is located in the Basic Flow Control Area. Tables 2-4 summarize the KCRTS inputs. Table 2 -Existing Conditions Areas (acres) Till Forest Till Grass Impervious 0.00 0.26 0.03 Table 3 -Developed Conditions Areas (acres) Till Forest Till Grass Impervious 0.00 0.10 0.19 Table 4 -KCRTS Inputs Rainfall Region SeaTac Scale Factor 1.0 Tables 5 summarizes the KCRTS output. Without taking into account the proposed infiltration trenches, the 100-year peak flow rate of the developed site is only 0.042 cfs higher than the existing condition. Table 5 -100 Year Peak Runoff Rates (els) Existing Condition Developed Condition Difference in Discharge 0.069 0.111 0.042 Infiltration Facility Design Although infiltration facilities are not required for this project based on the 0.50 cfs exemption; infiltration facilities are proposed as a BMP to help reduce the stormwater impacts of the proposed development. A soils analysis was performed and it was determined that the project soils can be classified as medium sand. Per section C.2.2.3, infiltration trenches must be at least 30 feet in length (60 square feet bottom area) per 1,000 square feet of impervious surface The Concept Group Page 3 Meyer Town homes Short Plat -DRAFT Technical Information Report September 2008 based on a 2 feet wide bottom. The infiltration trenches for the roof drains have been designed with an overflow outlet to sheet flow storm water during heavy rainfall events. Refer to Table 2 and Appendix D for infiltration trench calculations and details. Table 2 -Infiltration Facility Design Areas (SF) New Impervious Surface Required Infiltration Provided Infiltration Bottom Area Bottom Area 1,414 (lot 1) 0 combined w/ access road system 1,650 (lot 21 0 combined w/ access road system 1,978 (lot 3) 0 120 3,100 (shoulder & access 0 265 driveway) Water Quality Although the project will create 8,142 square feet of new impervious surface, approximately 4,280 square feet is pollution-generating impervious surface (PGIS). PGIS is defined as "an impervious surface considered to be a significant source of pollutants in surface and storm water runoff. Such surfaces include those subject to vehicular use or storage of erodible or leachable materials, wastes, or chemicals, and which receive direct rainfall or the run-on or blow-in of rainfall." Non-metal rooftops are not considered PGIS; therefore, are not included in the PGIS area calculations. Water quality is not required for this project because the project does not create more than 5,000 sq ft of pollution generating impervious surfaces as defined in the KCSWM. Refer to Appendix D for water quality calculations SECTION 5: CONVEYANCE SYSTEM This project does not include any proposed conveyance systems. 100-Year Flood/Overflow Condition Overflow of the stormwater infiltration facility will sheet flow to the eastern properties and eventually discharge to the drainage ditches located along SE 192"d Street. SECTION 6: SPECIAL REPORTS AND STUDIES There are no special reports or studies are expected to be prepared for this project. SECTION 7: OTHER PERMITS Permit for this project included: • Short Plat Approval • Building Construction Perm it SECTION 8: CSWPP (EROSION CONTROL) ANALYSIS AND DESIGN All erosion and sediment control measures shall be governed by the requirements of the City of Renton. An Erosion and Sedimentation Control plan has been prepared to The Concept Group Page 4 Meyer Town homes Short Plat -DRAFT Technical Information Report September 2008 assist the contractor in complying with these requirements and designed to prevent sediment-laden run-off from leaving the site during construction. Refer to Appendix E for Erosion Control plans and details. The erosion potential of the site is influenced by four major factors: soil characteristics, vegetative cover, topography, and climate. Erosion/ sedimentation control is achieved by a combination of structural measures, cover measures, and construction practices that are tailored to fit the specific site. Construction Sequence and Procedure Prior to the start of any grading activity upon the site, all erosion control measures, including installation of a stabilized construction entrance, shall be installed in accordance with the construction documents. The best construction practice will be employed to properly clear and grade the site and to schedule construction activities. The planned construction sequence for the construction of the site is as fol lows: 1. Pre-construction meeting. 2. Post sign with name and phone number of ESC supervisor (may be consolidated with the required notice of construction sign). 3. Flag or fence clearing limits. 4. Install catch basin protection if required. 5. Grade and install construction entrance(s). 6. Install perimeter protection (silt fence, brush barrier, etc.). 7. Construct sediment ponds and traps. 8. Grade and stabilize construction roads. 9. Construct surface water controls (interceptor dikes, pipe slope drains, etc.) simultaneously with clearing and grading for project development. 10. Maintain erosion control measures in accordance with King County standards and manufacturer's recommendations. 11. Relocate erosion control measures or install new measures so that as site conditions change the erosion and sediment control is always in accordance with the King County Erosion and Sediment Control Standards. 12.Cover all areas that will be unworked for more than seven days during the dry season or two days during the wet season with straw, wood fiber mulch, compost, plastic sheeting or equivalent. 13.Stabilize all areas that reach final grade within seven days. 14. Seed or sod any areas to remain unworked for more than 30 days. 15. Upon completion of the project, all disturbed areas must be stabilized and BMPs removed if appropriate. Trapping Sediment Structural control measures will be used to reduce erosion and retain sediment on the construction site. The control measures wi 11 be selected to fit specific site and seasonal conditions. The Concept Group Page 5 Meyer Town homes Short Plat -DRAFT Technical Information Report September 2008 The following structural items will be used to control erosion and sedimentation processes: • Temporary gravel construction entrance • Filter fabric fences (Silt fences) • Ground cover measures such as straw cover and/or hydroseeding • Inlet protection Vehicle tracking of mud off-site shall be avoided. Installation of a gravel construction entrance will be installed at a location to enter the site. The entrances are a minimum requirement and may be supplemented if tracking of mud onto public streets becomes excessive. SECTION 9: BOND QUANTITIES AND DECLARATIONS OF COVENANTS None known at the time this report was prepared. SECTION 10: OPERATIONS AND MAINTENANCE The owner or operator of the project shall be responsible for maintaining the stormwater facilities in accordance with the requirements as attached in Appendix F. Proper maintenance is important for adequate functioning of the stormwater facilities. If it is unclear whether a problem exists, contact a Professional Engineer. The Concept Group Page 6 Meyer Townhomes Short Plat -DRAFT Technical Information Report The Concept Group Appendix A Vicinity Map, Site Photos and Property Information September 2008 Appendices Meyer T own homes Sh ort Plat -DRAFT Tec h nica l I nformation Report <j<S'o. ,'I ' T he Concept Grou p J{ f < -s ;! ._ ,~\SI ~I I ~, I Se Carr Rd Se 179th Rt J: ., !><> 180.!I! St ~ ;; Sc 181st St~ cl} I Vicinity Maps not -to-scale <I V) j: < ~ Se ptem ber 2008 !J ~ .... ~ I "' " ~ -S<! L68tl\ Sl I .Se Wltl\Sl l Se 171st St Se 171.st Pl Sc 17Sth St 8 enson Hill 0 Se l73J d St i :g :(I L72 n, Appendices Meyer Tow nhomes Short Plat -DRAFT Tech nical Information Report Septe mber 2008 View of front yard of subject property. View of back ya rd o f subject property. The Concept Group Appendices Meyer T ownhomes Short Plat -DRAFT Te chn ical Information Rep ort September 2008 Driveway cu lve rt in fr o nt of subject property . The Concept Group Appendi ces Meyer Townhomes Short Plat -DRAFT Techni cal I nformat ion Report September 2008 Lookin g so uth on l 0811 Way SE Th e Concept Group Appendi ces Meyer Town homes Short Plat -DRAFT Techni cal Information Report September 2008 The Concept Group Appendices UI Kins County Assessor information for parcel number 1626800060 Taxpayer name MARSHALL CHARLES Parcel number 1626800060 Mailing address 10839 SE 173RD ST RENTON WA 98055 Tax Account number 162680006002 Address(es) al this parcel 10839 SE 173RD ST 98055 ~~ascription--------~---~--- CLIFFORDS 1ST ADD -1-S8l8s/QUiC1airTisrrransters Levy code Jurisdiction Present use Appraised value -------------~---~--------- Sale date Sale price Buyer Seller ·,$: 05-27-2008 $0 MARSHALL CHARLES MARSHALL JENNIFER T 05-22-2008 $281,500 MARSHALL CHARLES SEFRIOUI ANTISSAR 04-12-2007 $221,000 SEFRIOUI ANTISSAR scon DUANE L 2128 RENTON Single Family(Res Use/Zone) $187,000 234 84_5_4. None 227782~.2~--~2~0gOb70~4~1~3~0~0f23~1g4t__~S~<~at~"~'"'Y"i'.."'""'a~rra~o~<yy_cOe,eee~d_<E~,~ta~<~e~S~e~tt~le~m~e~o~t I_ Parcel description Property name Plat name CLIFFORD'S 1 ST ADD Waler system WATER DISTRICT Property type R • RESIDENTIAL Plat block 2 Present use Single Famlly(Res Use/Zone) Plallot 6 Loi area 12,722 sq. ft. (0.29 acres) Q-S-T-R SE-29-23-5 ' Residential buildingd~sc~rip~t~io~n~----- Building Year built Year renovated Stories Building grade 1 of 1 1952 • 6 • Low Average Condi lion Average Finished basement grade NONE OR UNKNOWN Total living sq. ft. 1st floor sq. ft. Half floor sq. ft. 2nd floor sq. ft. Upper floor sq. ft. Total basement sq. ft. Finished basement sq. ft. Basement garage sq. ft Attached garage sq. ft. Open porch sq. ft. Enclosed porch sq. ft. Deck sq. ft. Sewer system PUBLIC Access PUBLIC Street surface PAVED 1,160 Bedrooms 3 1,160 Baths 0 1/2 baths 0 0 3/4 baths 0 0 Single story fireplace 0 Multi-story fireplace 0 0 Free-standing fireplace • 0 Percent brick or stone 0 0 Daylight basement N 60 Heat system Elec BB 0 Heat source Electricity 0 2008 TAXABLE 2007 TAXABLE 2006 TAXABLE NONE OR UNKNOWN NONE OR UNKNOWN NONE OR UNKNOWN $71,000 (land) + lli..QQQ (lmpro11emeols) $170,000 (total) $63,000 (land) + lli.2QQ {impro11emeols) $145,000 (total) $59,000 (land) + lZI.2QQ (impfOllernents) --------------'$_,_,13"C'6,000 (~ .... Related resources .. + $113 000 (improvernenls) $187,000 (total) $71.000 (land) + $99 000 (improvements) $170,000 (total) $63.000 (land) + $82 000 (improvements) $145,000 {total) $59.000 (land) + $77 ODO (improvements) $136,000 (total) King County Assessor: Submit a request to correct information in this report King County Assessor: eReal Prop arty Report (PDF format requires Acrobat) King County Assessor: Quarter Section Map (PDF format requires Acrobat) King County GIS: Property information FAQ King County GJS: Districts and Development Conditions Report (a detailed report about the location of this property) King County DOES: Permit Applications Report (for unincorporated areas only) King County Treasury Operations: Proparty Tax Information for this property King County Recorders Office: Excise Tax Affidavits Report King County Recorders Office: Scanned Images of plats. King County Recorders Office: Scanned images of surveys and other map dcg;1,1m_i?nts. Open iMAP to this property (requires a high speed internet connection) Open Parcel Viewer to this property (any connection speed, but less features than iMAP) This report was generated on 9/26/200812:13:08 PM Contact us at g,scentcr@k1ogco11nty gov. © 2008 King County U) King County King County Districts and Development Conditions for parcel 1626800060 Parcel number 1626800060 Drainage Basin Address 10839 SE 173RD ST Wa!!l!C§hed Jurisdiction Renton WRIA Zipcode 98055 PLSS Kroll Map page 601 Latitude Thomas Guide page ••• Longitude 1·-Electoral Districts Voting district RNT 11-0804 King County Council distnct District 5, Julia Patterson (206) 296-1005 t:iiJ Congressional district Leglslalive district School district 9 11 Renton #403 Black River DUW!!rnish • Green River Ouwami_~tl_-Gr~en (9J SE-29-23-5 47.4472 -122.19475 Fire district Water d1str1cl Sewer district Water&. Sewer district -----------~=cc-~~------------------- does not apply does not apply does not apply Soos Creek Water & Sewer District Parks & Recreation distr1cl does not apply Hospital district Sealtle school board districl does not apply (not in SeaWe) Rural library district Public Hospital District No. 1 does not apply Dislrict Court electoral district Southeast Tribal Lands? No King County zoning P-Suffix conditions Comprehensive Plan NA, c:he<:k with Jurisdiction None um Urban Growth Area Urban Unincorporated Area Council does not apply Community Planning Area Soos Creek Coal mine hazards? Yes Erosion hazards? None mapped Landslide hazards? None mapped Seismic hazards? None mapped Water serv,c:i; QJB::J_'.l_l_n_g_ar_e,a Roads MPS _~Qrll;' does not apply 334 Jransportat,on concurrency zone 784 Forest Production district? No Agricultural Production district? No Rural cle.irirm lmrts ;rnply? No Critical aquifer rechsrqe <:irea? None mapped 100-yearflood plain? None mapped WeUands at this parcel? None mapped This report was generated on 9/26/2008 12:15:04 PM Contact us at giscenter@kingcounty.gov. (c) 2008 King Counly Meyer Townhomes Short Plat -DRAFT Technical Information Report The Concept Group Appendix B Soils Information September 2008 Appendices 560520 560540 560560 I I I 560520 560540 560560 N A 0 15 30 60 0 50 100 200 USDA Natural Resources 1iii Conservation Service Soil Map-King County Area , Washington (Meyer Townho mes Short Plat) 560580 560!l00 560620 I I I 560580 560600 560620 Meters 90 Feet 300 Web Soil Survey 2.0 National Coopera ti ve Soi l Survey 560640 I 560640 560660 560680 I == 0 <O N "' ~ "' ~ "' SJ ~ N "' "' N "' 0 ~ ~ 0 "' "' ~ "' 0 <O "' ~ "' 0 ;! "' ~ 0 N "' ~ "' 0 ~ :ll N "' I 560660 I 560680 9/26/2008 Page 1 of 3 = Soil Map-King County Area, Washington (Meyer Townhomes Short Plat) MAP LEGEND MAP INFORMATION Area of Interest (AOI) D Area of Interest (AOI) Soils Soil Map Units Special Point Features "" Blowout 181 Borrow Pit * Clay Spot • Closed Depression X Gravel Pit Gravelly Spot @ Landfill A Lava Flow ... Marsh .. Mine or Quarry @ Miscellaneous Water @ Perennial Water V Rock Outcrop + Saline Spot Sandy Spot -=-Severely Eroded Spot ~ Sinkhole 9 Slide or Slip /6 Sadie Spot s Spoil Area () Stony Spot Natural Resources Conservation Service Ol Very Stony Spot t Wet Spot .. Other Speclal Line Features "'" Gully Short Steep Slope A, Other Political Features Municipalities • Cities D Urban Areas Water Features :::::::J Oceans ~ Streams and Canals Transportation +++ Ralls Roads """' Interstate Highways ,,,.,, US Routes State Highways -Local Roads Other Roads Original soil survey map sheets were prepared at publication scale. Viewing scale and printing scale, however, may vary from the original. Please rely on the bar scale on each map sheet for proper map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov Coordinate System: UTM Zone 10N This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Survey Area Data: King County Area, Washington Version 4, Nov 21, 2006 Dale(s) aerial images were photographed: 7/10/1990; 7/18/1990 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result. some minor shifting of map unit boundaries may be evident. Web Soil Survey 2.0 National Cooperative Soil Survey 9/26/2008 Page 2 of 3 Drainage Class-King County Area, Washington Meyer T ownhomes Short Plat Drainage Class Drainage Class-Summary by Map Unit -King County Area, Washington Map unit symbol Map unit name I Rating Acres in AOI Percent of AOI AgC Alderwood gravelly Moderately well drained 0.8 14.5% sandy loam, 6 to 15 percent slopes --· ---- C 1 Arents, Alderwood Moderately well drained 4.8 _ 85.5% I material, 6 to 15 percent slopes -- I Totals for Area of Interest (AOI) -~---______ s.a I ____ 100.0% I Description "Drainage class (natural)" refers to the frequency and duration of wet periods under conditions similar to those under which the soil formed. Alterations of the water regime by human activities, either through drainage or irrigation, are not a consideration unless they have significantly changed the morphology of the soil. Seven classes of natural soil drainage are recognized-excessively drained, somewhat excessively drained, well drained, moderately well drained, somewhat poorly drained, poorly drained, and very poorly drained. These classes are defined in the "Soil Survey Manual." Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Natural Resources Conservation Service Web Soil Survey 2.0 National Cooperative Soil Survey 9/2612008 Page 3 of 3 3.2.2 KCRTS/RUNOFF FILES METHOD-GENERATING 71ME SERIES TABLE 3.2.2.B EQUIVALENCE BETWEEN SCS SOIL TYPES AND KCRTS SOIL TYPES SCS Soil Type scs KCRTS Soll Notes Hydro logic Group Soil Group Alderwood (AoB, AnC, AaDl C Till Arents, Alderwood Material (AmB, AmC) C Till Arents, Everett Material (An) B Outwash 1 Beausite /BeC, BeD, BeFI C Till 2 Bellingham (Bh) D Till 3 Brisool Br) D Till 3 Buckley Bu) D Till 4 Earlmont (Ea) D Till 3 Edgewick (Ed) C Till 3 Everett EvB, EvC, EvD. EwC) AIB Outwash 1 Indianola (lnC, lnA, lnD) A Outwash 1 Kitsap (KpB, KpC, KpD) C Till Klaus KsC) C Outwash 1 Neilton NeC) A Outwash 1 Newbero (Nal B Till 3 Nooksack (Nkl C Till 3 Norma (No) D Till 3 Orcas (Or) D Wetland Oridia (Os) D Till 3 Ovall OvC, OvD, OvFl C TIii 2 Pilchuck /Pc) C Till 3 Puget Pu) D Till 3 Puyallui (Pvl B Till 3 Ragnar RaC., RaD, RaC, RaEl B Outwash 1 Renton Re) D nu 3 Salal (Sa) C Till 3 Sammamish (Sh) D Till 3 Seattle (Sk) D Wetland Shalcar (Sm) D Till 3 Si {Sn) C Till 3 Snohomish (So, Sr) D Till 3 Sultan Su) C Till 3 Tukwila {Tu) D TIii 3 Woodinville (Wo) D Till 3 Notes: 1. Where outwash soils are saturated or underlain at shallow depth (<5 feet) by glacial till, they should be treated as till soils. 2. These are bedrock soils, but calibration of HSPF by King County DNRP shows bedrock soils to have similar hydrologic response to till soils. 3. These are alluvial soils, some of which are underlain by glacial till or have a seasonally high water table. In the absence of detailed study, these soils should be treated as till soils. 4. Buckley soils are formed on the low-permeability Osceola mudflow. Hydrologic response is assumed to be similar to that of till soils. 2005 Surface Water Design Manual 112412005 3-25 Report to: Anna T. Nguyen, P.E. The Concept Group Seattle, WA Final Report for: Soil samples submitted for analysis Meyer T ownhomes Short Plat LabCor Portland Job No.: 082006 [S5] Particle Sizing and Moisture Content of Soil Samples Analyst: Liza Shaw September 23, 2008 LabCor Portland, Inc. 1.1. Test Methods For particle sizing, soils were dried to ambient conditions. After samples were sufficiently dry, the samples were passed through a series of sieves and the fraction remaining on each sieve was weighed. The fraction of the sample that was left in the pan after sieving represents fine silt and clays. To further break down this fraction requires hydrometer analysis at an extra cost. General classification of soil types were as follows: Classification Coarse Gravel Medium Gravel Fine Gravel Verv Fine Gravel Verv Coarse Sand Coarse Sand Medium Sand Fine Sand Very Fine Sand Silt Clay 1.2. Moisture Content Meyer Kent Hole 2 [S5] Initial w,,;,,htln\ 1165.00 Dried Weiahtfn\ 1101.80 Moisture Weicht 63.20 % Moisture 5.42 4321 SW Corbett Ave, Ste. A Portland, OR 97239 Particle diameter >19.0mm >9.5mm >4.75mm >2.0mm >850µm >425um >250µm >106µm >75µm >63µm <63µm Tel: (503) 224-5055 Fax: (503} 228-8282 Page 2 of4 LabCor Portland, Inc. 2.2. Particle Size Breakdown Meyer Kent Hole 2 [S5] Coarse Gravel Sieve Size >19.0mm Weight In\ 0.00 % of Total 0.00 Very Very Very Medium Fine Fine Course Coarse Medium Fine Fine Gravel Gravel Gravel Sand Sand Sand Sand Sand Silt >9.5mm >4.75mm >2.0mm >850um >425um >250um >106um >75um >63um 16.40 41.60 55.80 46.80 117.00 171.40 263.80 68.80 65.00 1.49 3.78 5.06 4.25 10.62 15.56 23.94 6.24 5.90 Meyer Kent Hole 2 [S5] Jo. oo r-:::-:::::-c::--:-:-----::::;~:;,:;:;;:;;;::;-:-;;-c::717~--;-:-:-:---:-i iii ... 0 1- 'o #. 25.00 fi*'~r::,----~= 20.00 +::-~~7---~~~~ 15.00 10.00 f-,-~~;ir------,~ei 5.00 0.00 .i.;;..-;:::2:;;;.:;,._~-~..;..;;;;:..;...;;.;..,.~;....;..~~""""';a;.._~ ........ _. Particle Size Clav Fines(<63um) 244.60 22.20 4321 SW Corbett Ave, Ste. A Portland, OR 97239 Tel: (503) 224-5055 Fax: (503) 228-8282 Page 3 of4 Total 1091.20 99.04 LabCor Portland, Inc. This test report relates only to the items tested in this report. Results are subject to the variation of field sub sampling, the accuracy of the balance as well as other variations within the procedure. If further clarification of these results is needed, please do not hesitate to call. Thank you for allowing the staff at Lab/Cor Portland, Inc. the opportunity to provide you with analytical services. Sincerely, ., John Harris Laboratory Director 4321 SW Corbett Ave, Ste. A Portland, OR 97239 Tel: (503) 224-5055 Fax: (503) 228-8282 Page 4 of 4 Meyer Townhomes Short Plat -DRAFT Technical Information Report The Concept Group Appendix C Proposed Drainage Plan September 2008 Appendices ' ' J ~IJ I ,. Ii: !jl "' "' w " 0 I z ~ a: ~ " ' ' i I l ! , c \ I . . I I • ~ I ~---.c·lr ; ~(') I~ ;\ : ~ 1i < 'w ~~ \ ~ 0) I \i NI \i ,1 \I . I \ I .,, :~ ~ I ' ' ' ~ I '· w,-.''"."'"':',,n- -~~ " "' 1---' 5.0'~ t.N()SCAp( S11II' --.J.~~fi;. EX.'IA~IIEIER ------" ~~, :.---7---------' ' ~~ "" ~I >'< {],5:IOSQ.FT.) '-, •~ """-, ....... ,, ~ -- LOT3 (5,2'J15Q.fT.) ~:418.00 FOCITMIITT:1,278 SQ, FT. ~~~ 11 ~z- ~ _5.~lrx 'I ,,~' I\ l 1 Ci.:0+2 CNU: 3,~~-FT.) ~: 2,na SQ. ff.) Fff: 411.0II ff'E: 417.00 ATTAOIID'IOWNIIDUSe\N11"fL A TtlWNID.ISELNTU 13 lF r 1',,,c ROOF' SUI _ ..... r-u"' \ t ~~~ I ~_J t L \ ~~fu~Y I C2,•:rwx:mtxt'DJ ' I (1\ 1: ~ , I I ~ I/ ' I:.. , .... ~ ., ow-\;c' , 1111 P._____'f.. !; ~ -, -, CSP--HI/VNE GRAl[-NID - CIL/WAlER S£PIIRATO!l_.Tl1 RI£ MEliH~-- PE:RC:.O.R.S1110ElAL.5 -,;_ / 4 .\@@ - " }\_ O\Oflc,f ~) 211\FB"RCP:008.~ ~""'"='"~-STA~~ 'DT2 ' ' ' j C'.:::_'.J \_Pl!Cf'OStD :;a: sou <:::PVT. RCW>/1.0T I ~ 2::J!OO' 'SEE UllUTY ~ ;~~XT~TRA~ TREJ«:11 @\ PLAN >l(IOllJ<lll.l;IW'lfC= 10 ~ 0 $ ,o / ~ \\::: '"""'""' "' """' / I:} 'I I ''@ B" e soutilPVC ~ ........, /1 ....... />. \~,--· , l CALL 48 HOURS BEFORE YOU DIG I.ffll0.42+5555 NOTES, I -fN..Clt.....:.SCAL.E I. stE !IET CV mt l!CEN'.I. IE ~ CE) FOR N'f"FDIN... I 5 0 > '" ~1 • ~I ~-- l ---I E..2iil--e::-. ~ ~ F>l8185 ~-, •• ,. 7'.- ,o,oo .. -11+50 5 2.5 0 l5 '"00 PAOFLE 11 ......... Z. ==»._ SHAU. fE.D \OFI' ML <RADES PIIIOR TO 3. !IEE Stm OTt FOR ~ DETMS. .... Sil:51&TDRl!Ftlll;IIIAIU,litPUN~PIIO'l.E M.(IIG st 173fl0 S'llltf1. e e ~ ~ CITY OF MEYER TOWNHOMES SHORT PLAT 10839-SE 173RD STREET RENTON, WA 98055 Me __ _ Me __ _ Me __ _ M~--- " _ ...,_ {f6""-i\ ,a, ltO.MEIER ~ f'1ffflfflft!!!"'=.::-~1 ~ ~ I !R RENTON ·1 _ ----~---·-I .'.~;::I ':._~:' I I J ~ 1 JM.1_1g:::-1 ~1 '7' 1----1 DIWNAGEPLANANDPAORE n -tr1ir ~9 ~e ! 41•0 414.2 ,.,- 11 ~ 2 .... 8 ..... • 1-,,,;_ ? •1n• MEYER TOWNHOMES SHORT PLAT " . . ! r-~, i F lJ F 'l ll,l! I ~ • F ~ . ll ' 1 • • i• ' ~ •• ' : :!: • ' -:::., : ! C :, 5 I ' I -' ' ;p > : i:;; i ' i I I • 'l ' I I ij I I • I • " I' ' .. • ' I ' i -o • ' ~i' " ' ' I' ' . • •!::: i ij • ' , . -., ' !, r "' p 5~ C ; -,,, ' I ,, ' ' !1 i ~ ' "--• 410.13 l'j~~ h '. § •• L 1~ ! 5 I ~ 0 I "' ffl I "' ~ i J ! j I } -.. -·--,.. --==11 I -' ' "' ............. (JPJ l'. ' ' ' :0 > T -Gt:'m; "-"' @> miiii,"ioim ~::=z p-::.~. [ u~-4 ........ 4,H;;pc···, ..... man: >/1'--("'I -8IC"lt:IN @ "-J[i:-''" ,.,~ ·1 u J l:7--I . ?J "' -:,,r-...rirw, SECTIOII@ CEMENT CONCRETE OIIVEWAY ENTRANCE TYPE 1 PER (:nY OF RElfflll STNIDNID OCTAi. R»l-2 SCAI.L: NCIIE % , __ _ "41t'_ II'_ -r•eu& Flll :..OT OCTAL SEE STD DETM. .., .. , :!:l J/~· JCNf ~ AEH OE1'AL ·111!&. f I~; I "'!l?ll!< I Cl!!M!!NI' OONCfl!'I'! IDEWILX '°"""" 10 CUii CEMENT CONCfETE SIDEWALK PER Q1Y Cf ~ STMDMO DET"'-~ SCALE:NONE i ~ • ' NOTES, SElf-LOCK YNEJ GR.lTE MIIHUFACTI.ffl SU9A:CT TO l,WflQYN,. 8Y EHGlNE!R. 2. US£ 11'!11 T'Ml L.DCXNG OCl_fS 5/8"·11 r,rc STAINL!SS TIP£ J04 m:n SOll([f f£AII (llll£N IOD) 801.lS, 2" LONG. NOTE SI.OT DETAIL. 3. IIAmllAL IS OOC1l.E IION li!iTII A53l!I ll'lAD£ II0-55,-llll. '4. "OOll'Ml. 'IQ SlllEMI DIii' IIO PW.UTNOS" IIAY BE l,OCA TB) CII IICIIIEJI Nl£A ,. 9W.L «wOlllil TO E 7.05 Cf" STANIIAAD ........... e. EUlNG IS NOT PEJUrnD. 7. EDCES SH.Ill HA\€ 0.125° lblWS. (U25° QWaR OR ...,,._ & USEAlil-lll!Et1Dl,....V~QltA1EIIISM:\01ICIII. ...... u:\€LIIG PNJ (8 •II ~ l-,,.. . ,, .. ,,,,.. ; .,.,,,J ',· \· \' j· \· ',· ~I !s V/JJED <lRAlE DETAL -- ' I · 1 Cl'IOI.IND MOl.tlfTID STR:ET NAME SIGNS l POI CIT'I' Cf" RElffllN STNIIMiD DETM. Q011 -----..,_"""' __ ... __ ..... &;--- T!>OOl-•!>mJ_,, ti -.Tl«OIGl'l'GII'- ' G)G) Prl!PPZ@@ I ww;,,a;u I PER UTY OF RElfflll STNGUIO DETAa. lll11 --=--R08l65 "' ~ .;,!·~ ~f'tWi A. T. fllGUVEN ffl lt1,11tl1J>PR!H.H.l'HAN I .,:.':... I X:...""!.::.:.., !..:..!..!l:!:. ,r. 11 vr---,.. ,.. " s--r1. ~ ... ... .... f -.... -~ i:,l"..!:ll,":lo'&I"' IUN>EW CATCH BA8N GIJ11ER l'l.AN :.:. - l.',I I . ~,1 ti . : ·"'-il'lll'li,= .. "il.-I .. -: , .•. " iii-· k • . : ." . ~ ~·1= .. '-~ E011CN@ :im"ftl'll m"L- CEMENT CONCfETE CURB AN) Cll1TTER PLAN PER Q1Y OF flfM1tJN ST#IWID DETM. RIOI 5tALE: NCllE ., SECTIOII@ J/8' DP~CII -'lNT r-COENT CONCRE'lE SOCWM.l( o.oz FT./n. h 1:1 r~f:.~-~~r , ....... N- """""-- .... 1. -EIO-SCDI - 2. :.:n":: =..~--1 (llltAftl8fl I ca lmllll -----'Clll'!IIICl'II- DEBAIB EIAffilER DETAL PBI (nY ti R8fflll S'IMDNID DCTM. 1111411 -- •NO'lt: TI)P (II" LI' ~f l:fl'«ll/lT N'PROl,l)I CB.ENT CONCFETE VEffflCAL ct.m NO GUTTER -- fECCUSIJED FCR WPPDIIL n ••~~~- ft ••~~~- ft ••~~~- ft ~~~~~- MEYER TOWNHOMES SHORT PLAT ......... CITY OF RENTON 10839-SE 173RD STREET RENTON, WA 98055 ® -~-....... ~ DETAILS Meyer Townhomes Short Plat -DRAFT Technical Information Report The Concept Group Appendix D Flow Control, Water Quality and Infiltration Design September 2008 Appendices C.1.3 APPLICATION OF FLOW CONTROL BMPS FIGURE C.1.3.A FLOWCHART FOR DETERMINING APPLICATION OF FLOW CONTROL BMPS Is the project on a site/lot Yes . Is it feasible and smaller than 22,000 square feet? ~ applicable to implement full Yes No further BMPs Apply one or more of the following to impervious area dispersion for the required. Note: :.i: 10% of site/lot for s/tWlot sizes <11,000 sf and::. 20% of roof area as per Any proposed site/lot for site/lot sizes between 11,000 and 22,000 sf (For Section C.2.1? connection of roof projects located in critical aquifer recharge areas these Noy downspouts to impervious area amounts double): local drainage 1. Limited Infiltration (Section C.2.3) Is it feasible system must be 2. Basic Dispersion (Section C.2.4) via pertorated 3. Rain Garden (Section C.2.5) and applicable pipe connection 4. Permeable Pavement (Section C.2.6) No to implement Yes . per Section -full Infiltration 5. Rainwater Harvesting (Section C.2.7) " C.2.11. No 6. Vegetated Roof (Section C.2.8) of the roof 7. Reduced Impervious Service Credit (Section C.2.9) runoff as per 8. Native Growth Retention Credit (Section C.2.1 O) Section C.2.2? I Notes: No flow control BMPs are required tor new pervious surfaces. Water aualitv lm.....,.cts are adeauatelv addressed with the above flow control BMPs. The project must be a site/lot I Is it feasible greater than or equal to 22,000 square feet? I and applicable to implement full Yes No further BMPs dispersion on required. Note: all target Jmpervlous Any proposed surface as per connection of roof One or more of the following BMPs must be implemented Section C.2.1? downspouts to for target Impervious surface not addressed with full No f local drainage dispersion or with full infiltration of roof runoff: Is it feasible and system must be 1. Full Infiltration {Section C.2.2) No applicable to implement via perforated 2. Limited lnflltratlon (Section C.2.3) full lnflltratlon of the pipe connection 3. Basic Dispersion (Section C.2.4) roof runoff as per per Section 4. Rain Garden (Section C.2.5) Section C.2.2? C.2.11. 5. Permeable Pavement (Section C.2.6) 6. Rainwater Harvesting (Section C.2.7) Yesy 7. Vegetated Roof (Section C.2.8) Is there any remaining target 8. Reduced Impervious Service Credit (Section C.2.9) Yes Impervious surface not addressed No 9. Native Growth Retention Credit (Section C.2.1 OI with full dispersion or with full I infiltration of roof runoff? Note: Flow control BMPs are required for all new pervlous surface when it exceeds 35,000 sf. Flow control BMPs must be applied in the following order of preference: 1. The feasibility and applicability of full dispersion as detailed in Section C.2.1 must be evaluated for all new pervious surfaces. 2. For those pervious surfaces not addressed in Requirement 1 above, one or more of the following BMPs must be implemented: Basic Dispersion (Section C.2.4) Rain Garden /Section C.2.5) Note: The following extra water quality provisions must be implemented if the project results in 5,000 sf or more of additional pollution generating Impervious surlace from which runoff is not fully dispersed in accordance with Section C.2.1: 1. Reduce existing or proposed pollution generating impervious surface so that the 5,000 sf threshold is not triggered. 2. Provide water quality facilities designed by a licensed civil engineer in accordance with Section 1.2.8 of the SWDM. 2005 Surface Water Design Manual -Appendix C l/24/2005 C-17 SECTION C.2 FLOW CONTROL BMPs 6" 6" 12" 1/24/2005 FIGURE C.2.2.A TYPICAL TRENCH INFILTRATION SYSTEM PLAN VIEW NTS ,-4" rigid or 6" flexible / perforated pipe (-······························· ········. / ·····: ----------. --· ..... --------·---------....... -. --. roof drain infiltration trench sump w/solid lid .Y. % ,..., ,,. PLAN VIEW NTS 4" rigid or 6" flexible pertorated pipe ................ ............ . -. ---... -,. ' overflow splash block fu•' ' : o a c=:'.:::::===:Jiiiiil~:::::==;::::;;::::µ::===::;-. bi• ' " .. . o. " ~m·,n so· . I : <....lo_ washed rock '-;lo. ·:-:.,:;, :::• e :..; ~ 11 • · min._ i" ~ 1 1/2"-3/4" ---:--.:::.·;';---'cc' '-.J O 6 c.:,, .'): min ~+.:··.,_._._ ... ", =--'-"--" filter fabric SECTION A NTS C-42 2005 Surface Water Design Manual -Appendix C David and Jeff Meyers Meyer Townhomes Short Plat 10839-SE 173RD ST Renton, WA 98055 House #1 Orivewav#1 House#2 Drivewav#2 House #3 Drivewav #3 Shoulder Improvement Access Road Total Roof Area Total PGIS 1 Total Pervious Area Total Proiect Size PGIS' = Area infiltrated = Impervious Surface = Total Project (ac) = Impervious Area (Sq Ft) Existina Pronosed 1,278 1,278 - 11,445 12,723 4,280 sq ft 8,142 sqft 8,142 sq ft 0.29 1,174 240 1,410 240 1,278 700 1,450 1,650 3,862 4,280 4,581 12 723 Infiltration Bottom Area, SF : ' ' .· oer KCSWM for medium sand .· .. .. Bottom Area = . 60 SF/ 1000 SF 85 99 119 KCRTS INPUT tEXISTING CONDITION/ TILL Grass 0.26 ACRE IMPERVIOUS 0.03 ACRE TOTAL 0.29 ACRE 100-year IH!!Bk flow 0.069 cfs KCRTS INPUT (DEVELOPED CONDITION) TILL GRASS 0.105 ACRE IMPERVIOUS 0.187 ACRE Infiltrated (not in model) ACRE TOTAL 0.29 ACRE 100-year peak flow 0.111 cfs 1100-year peak flow increase 0.042 Jets Meyer Townhomes Short Plat KCRTS Flow Rate Data September 26, 2008 Existing Condition Flow Frequency Analysis Time Series File:meyerexisting.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak (CFS) 0.030 4 2/09/01 2:00 0. 018 6 1/05/02 16:00 0.038 2 2/27 /03 7:00 0.012 8 8/26/04 2:00 0.018 7 1/05/05 8:00 0.031 3 1/18/06 16:00 0. 02 9 5 11/24/06 3:00 0.069 1 1/09/08 6:00 Computed Peaks Developed Condition Flow Frequency Analysis Time Series File:meyerdev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.055 6 2/09/01 2:00 0.045 8 1/05/02 16:00 0.066 3 2/27 /03 7:00 0.049 7 8/26/04 2:00 0.059 4 10/28/04 16:00 0.059 5 1/18/06 16:00 0.072 2 10/26/06 0:00 0 .111 1 1/09/08 6:00 Computed Peaks --Peaks Rank Return Prob (CFS) Period 0.069 l 100.00 0.990 0.038 2 25.00 0.960 0.031 3 10.00 0.900 0.030 4 5.00 0.800 0.029 5 3.00 0.667 0.018 6 2.00 0.500 0.018 7 1. 30 0.231 0.012 8 1.10 0. 091 0.059 50.00 0.980 -----Flow Frequency Analysis------- --Peaks Rank Return Prob (CFS) Period 0.111 1 100.00 0.990 0 .072 2 25.00 0. 960 0.066 3 10.00 0.900 0.059 4 5.00 0.800 0.059 5 3.00 0.667 0.055 6 2.00 0.500 0.049 7 1. 30 0.231 0.045 8 1.10 0.091 0.098 50.00 0.980 Meyer Townhomes Short Plat -DRAFT Technical Information Report The Concept Group Appendix E Erosion Control September 2008 Appendices SW1/4 OF SEl/4, SEC. 29-T23N-A5E, W.M. SEOlENCE OF CONSTRUCllQN, I "" :_''.I~~ iT-r--I, l 1i-;z-I. IJRIMlE l#J ATTOCI A PJl£CQIS1lllClD IIEElllG 11TH QlY OF FIEH1a.l. :t F1.AC a£IMolC IM1S .tfl) PROPERTY IMS. 3. STNCE: PIIIVAlE ~ MCI U1U11.S. ' ' I ~ ! I t: , i J ffl ~ ~ fl "' w i I l ' q-! i ' w I' , , w I ~~ ' i :1i-+t· ' ;1 f slir :1 II\ I w IZI .\~oot'1 \: I \ I ! " • :" ' f ' ' ' ' I I ~ 'I ' \I (~a~-l §I .O.TIJ,Qffi)TOMffll.lSE~ fl \ \ ~~i-@ --.4/,; LOT2 (3,510 SQ. FTJ &: .. (NET: 2,7lll SQ. FT.) IR:417.00 Iii. TOWNIIOIJSIE...iIT#l l ~ -r~--;·-·--CCJ ~.w -- LOT3 , II r 'I ,, ~)< !5~7SQ.FT.J l'R:41Bm RXITTfflfT:l,2785Q.FT. ~~~ I\ l \ J I I ,~ @/' ~ l \ i\ " \ , I NCI PR01ECllON (f'IP) I ~ , , \ I , : : / ' ' ' ' ' ' I I ,,,,;, N'I\ 1p \ X / ·~X X t Oif\6:0-----/-A t Ml.ll" I X I 'II '' ·I I ··'-..._ 51.l FENCE rni1, @ ·"· // /' /• 4. F\J,G EmlltC 1JIEES TO EE Soi.\m. 5. <RIJlE Nil IIS'TJU WMln' SPAU. WISTflUC10I EN1RANCL IS. ,csfl,L,L SU FENCING AS SHIM! ON 11£ Pl.ANS. 7. IMSTW. NEW SU SolHTAAY 9.WER. tlllMWlE l#J DllER llDJlU a f.111« NCI STAILIZE ID' PIIVAlE ACCESS R0,11). it IIMflAII EROSION CCN1R01. 111EAS11tES II ACORlNtCE WTH aTY 'S ROffCIN ST~ MCI ll/lfiUFACTUAEll'SAECOIIIIElll,,\llONS. 10. CO\UI AU. "1REAS lHAT a!. IE 1.11.-cm Ft1t IICIIE 111M SE'8I 0,1,TS ruwtc 1HE lllt'I' SEASON OR lWO OATS IUNl TI£ E SEASa1 STRo\W. IIXll Fll[JI IUDt, !DFOSI', P1.AS11: 5HEE1IIG OR EQUl'IAl.£HT. 11. STMIJ2E AU. NIE.IS -.illN SE\IEN DAYS OF lltAOalG 1IIAL QltMlL 12. !ffD OR !Cl) NfY '6V.S TO REltMI Uil'IIOINI) FllR IIOII: llWI JO OA'IS. 1l. UPON o:llil'l£1QI OF ll£ ~. STlrll.JZE ALL IIS1l.ll8ED MEAS #G REIMM: 111'1 ll'ON APPIIOYAL OF 1ltE KiPECTOR. EA08ION CONTROL NOTES IE'Cll( Alff COISTRIJClllll OR OE't8DPISfT AC1MT'I' OCCURS. ~ 1'11:-«JlfflRUCllDN IIEEtNl laJST BE 1£1.1) MlH 11£ mY a' Rl:lITTII DNl.CPWDIT SER'IICB DIWSICN. Pl.All AE\1EW PAO,ECT ...... 2, AI.L ~ rs cwnc AICI NIEA$ a' ~ATIOII PRE!IERVA1IOII ,1,5 PAESa&D lit 11£ Pl.Ml 9Wl Ii[ a.u.RI.T flACiGtP II lHI: FUD IJG Cll!EIMD DUIIIIC COfflllUClllN. 3. All AEQlJRD 9EDIIENTATOl/£IIO!iQt FACUIIES lllSI' BE CUISTRUC'IED AICI fl CIP£RA11111 1'111111 TO I.N[) Q£NIN(I N/r:A tm1ER CQISIIM;IDI 10 IIUI£ 11U.T SlllalOIT UIIDI WA'IEII IMl:S NOT ElfflR 11£ NA'IURAL tRMIAGE S'l'SlOl AI.L EII090N Nit) 9EDIIENT FN;11'1E5 9Wl BE ~~~~~~HAS,,~~~~ IIMflOIAN(:(. REPlACOIOO' AICI HD1ltllS TO EROSKII/SEl)IIENTATION caimta. S'ISEIS !llolrl.1. BE M: AElPCtlSlllJTI' rs M: PEllllrnL 4. lHE EROSICII AICI !EDMN1A11DN cafflldL ffl'IEII ON HS MIMIC /lllf. llllEIIEI TO BE IINIUI REOORllEWIS TO lilEET N!11Cll'AlED 911: C(Nl1ICNS. .OS COllmRIJC110N l'ROCftE'SSE'S AHO IJNEXPECltD QR SEASOHM. CO,UTIONS OC'!AlE, lM£ PERlllml: ~All,_ Nfl!CIPAIC lltAI IICRE EROSK11 .oJoll SEDl'WENTA TIOH COHlRO.. Fl<CUTES 'Mil BE l£t'ESSAA'I' TO INSIJRE C(M'l.['I[ Sl.TATOI Cl:lllllQ. cw 1liE PROPOSED SllE. DIJRtlG lHE OOJRSE Cf" ~Sl!IUCTION. IT ~All BE 11£ (R.JG.\TOI AAll RESl'Olsar rF lM£ PUIIIITEI TO .oDllR[SS ANT l£'f CIHlrOO!!S THAT WAT BE C!IL'.lED 8T MS AC!Nll(S AHO TO Pli:OWlED IJ)[UIONM. r~UTES, ovtR AN~ AflOI( IINIMI flEQ.JKIOTS, M. WAT BE NEEDED TO PROTECT ~T PROP(RTIES AAll WAlDI OOAUTY iE lHE flECOWIG DRAJ!AGI': SYSTDI. 5. ~~~s7:c:7ir::A~~~llOl~rs~I~~ QR R£10ITll»I fAWTIES. I I J ' l \ f "'-. l \ ''" / 1,/0/ i.7.[) 15. DUiie ff rlWE PEllOP rs OClllllER 1 'llllOUllt UMDt ll, ALL l'!IO.ltT Ol$lUl8Ql SCI. AIIEAS a.ATER lHAN 5,0IXI Sl1Jl,RE Ft£T, lHIIT Nit W1 I.IIIIORICED Ftll llCIIE lHAN TIIE..\IE {12) llllllS. SIIAI..I. BE CCMRED 11'1' IU.CJI. SODDIIIG,, QR PI.ASllt: D;MJIING. i ' i I I l N01E8' ' \\ 1. stt 5IUT CV FIii l.BDll. /1 ! 2. t:Ol1IACTCII $HAU_ fE..D \OFT ALL QUilES 1'111111 TO camRUCTOI. l 3. stt !it£ET FOR DR1 ORMNACE PlNt 4. SEE: SlttT ta FCIR lEW'(lltART EROSION Nil ElllDfTATMII ctlffllCI. OETMS 11=:.~::: ... (®} Q) (D)O>t«zl •(l(I0)6'0.ow liiiiilll'il------Iii I ,,.,u,,,-T(D)O>t«zl ,, I ..,.....,,..,.. -oo;,a,001 ~~-- PLAN to;lilllllltL-5':,IU !O ! O ~ \0 , """.,on.. "-...... _ CALI. 48 HOURS BEFORE YOU DIG 1-800-424-5555 IV I MTE 7. IN N1Y #1£,1, ~ 11,1,5 DI S'lllfftD a' \UlTATMII Ne aDE M1\0 .:R IS ANllOPAlm Ftll PEIIIUl OF 30 O.l,'l'S Cll MORE. ALL IIISIIIRIIED Nl£AS IA.IST II[ MGU.TD.Y STamD -.a.ON:. l:MSS l'I.Nl1IIC QR 01t£R N'PRO\Ul EROSION CCIN1RDL lREAlMEN'f N'PUCI&£ lU lHE lllllE iE '4111 11 QLDllCN. QRASS S00-AUllE W1. BE M:CEPTAII.E OIU ClRljQ M: lilDlffllS Cf N'11.. lllQIQH !E'm1D ll!1JJSM. SEEDN; IIAT l'llOCUI), IIOIE'oER, IIIEl€\O IT IS IN 1HE lfERE!T Cf M: P£JMTlEE, BUT laJST BE NJGIEllED WTH IIIU.tHC, J£T1tlC QR OH11 TJl£A1WIIT -..nl BY 1HE aTf Cf FIElllON. OUT!& nt: ftllfE> Ill: PEllOD. 8. ~~11:~.=:0~~1=0EJ>1HDCEEDSt I. A lEIIPORAR1' QtA\fl. CONS1AJC1IOt 9fTIWtClE. 24' X '9/ X t' a' 4 10 e ID! QWlltT SPAU.S 5IINJ. BE l.OCAED AT A1.L PONTSi Cf l9CA.Nt IIGAESS Nil ECll£SS 10 1HE CllNSTl'-'ClQI $nE. ~FOR NffOiAL EARTHWORK VOLUIE ESTMA1E8' LOCATION """'""""""' a l'RIYAlE MUSS IIOM) OJT(CY) " ~-PHAN ~PHMI !;J.;..NGUVEN 1.i.e.1 "i #![} H. H. PHAN FU.(CY) ~ ~ CITY OF RENTON _, __ ,__ ft ______ _ ft ft ft MEYER TOWNHOMES SHORT PLAT 1 OS39 • SE 173RD STREET RENTON, WA 98055 TESC PLAN AND NOTES -~------------------- EC1 FUEii ,AMII: IIAmlAI. 80" MlE: MUS. US[ STAPU:S C11 -lll'IGS 10 ATIAOt FAIIIIC ltl IIRE. r X r ~ nG,+,. ~ CII UU'IALDIT I s I ~ ~ fil I ~ " " " " " " " " " " " " " ~ :i-t -1 -----ff----1 'r ·,0:0: .JL_________ 11 }<o .. --------11 11 --tt-z----MR: I\ II ~ II UT90Tlllll ... ~~r II t :: :·· I._J 1 '"" , .. -.... ~- AU: S1EII. N01EI> 1. FOR SHEEf IUIOFF" CII RlUllalG Dl!iOIMCl£ fRtlll A 5QlMNT 1RAP CII PCNl.. :t 11W111U1 Sl.Cfl£ fflEl'NESS PEIIPOOCUI.AR 10 FENCE I.JI: 15 1: 1. 3. IWIIIIUU 9£ET OR O'o9UHD FLOW PATH L1NGIH TO TI£ F81Ct IS 100 1'£CT. 4. F !11111 C11 lESS IJI" TI£ SCL, 8"1' IIEGHl, IS FN: PARlllU:5 llMl..lSI 1HAN 1HE U.S. STIIHDNll SIE'<'E NO. 200. 1HE E0S SHQWl 1£ EQ.141. TO OR 5IIAU.ER tHAN 11£ Sl£'o!: SIZE: THAT 111511 IJI" 11£ SOL CNt PASS """" 5. 111: 111010t SHAU. at 8ACl(flJ.£I) TOt If INWlil DWE1ER *'51£1) (JIA'oa 8. fLlUI FAIIIIC Fe«D 9W.L BE IBKM1l aE!I "HY IIAIIE SOMll "IHBR ll5EFIL PURf>OSE, EIJT MOT !ERR 11£ UP5.DPE NIU HAS lllEN PERIUillEN1LY STaJZED. 7. fLlUI FAIIIIC FDICES SHAU. BE IIISPEC1ED MofllAlEI..Y M1EII EAOt IWN'ML Allll AT I.EAST DALY OOfllNG PRa..CNiED RMf"ltl. NfY REPM!S 9IAU. llt IUD£ MElAlU.Y. PER arr or REN"Ktl STNl"JARD DETAIL BOGG 1 SILT FENCE DETAIL CD ! SC4I.E: ,Kl£ ! ! l ~ I } N01EI> 1. EXTEKI 11£ FLlUI FENCE/tlH MESH IIEYOIII TI£ N£T CRltNll AT l£AST 1r tfl AU. SIJES. 2. fUCE If ltl '$' Q!AWl. O'IEll 11£ FI.IER ,MIIIIC;.tE IIIESI'.. 11£ IE'TH fl GIU,Wl. SHOWI BE AT L£ASTlrO'IEIIMEIITHN£Ttf'ENIIC. l. F 111: ilRAlll. FLIER attillES CUlGQ!D W1H !EDIIENT, M: tJtl,',R IIJST BE PW.ED AWAY fRtlll 11£ N£T Allll aUiNlll CII IIEPI..ACfD. 1111 41.IEIIIATNE #'PltO,l,CH 1JCUll BE 10 USE "II£ a.000ED GRAWl. AS RL Al«l PIil Flil94 GRA\n Ml1NI nt: IIUT. i f 1~CALL~~ .. ~HOU==.,.~ ~ BEFORE YOU DIG j 1-800-424-5555 .... C(llflRAC'IUI TO PROl(CT IIJO fRCII 1D1G / -~roM-~~,/, / EDIE Of" DIS1IN(I PA\UIDIT ~ PROWtE -·-1s *'51£1) tJt1.10. IIAQ(FU. fl 1RENOI Allll ON B01H SIJES W FUEii FfJa rMRC Cfl """""' r.r (Wt.) W)QDE)I ST#'8 Cll't9I 1110 ,cao.1(1 1r (1111.) II llEJ>lH. ] CAlOI BASIN -lill!AlE CU..\01" F itm.-m """"" ...... NOTES i b WIiii. 1. US£ ,4• TO r QUARRY !ll'AU.S OR a!U5HED ROCK FOi 9JIFM:IIG AS 9«l'IM IILl,lEJl,IL Will 'Ft£ IS """"""'"" :t 11£ !Cll fEE! INWl,I ta«at 5HAl..l. BE liNC1H9El AS IE<ESSNn' 10 IN!ilJRE IIAlERIAI. IS MOT TRJaD INTO 111: Pl.8.J: l'IQfT-fS-'1,t,Y. CONSTRUCT10N ENTRANCE DETAL 0 PfR QlY IJI" RDITCIN STNl>N!D DETIC. 191:a 2 -... l.D' l#Nrr {WAX.I .....,_ N.ET PROTECT10N DETAL 0 PER mY Cf" RElffllN STANJMD ct;T/C. BOllt-1 3 ,,.,,.,. IECCM.ENJED Fat Af'f'ROVAL n ••~~~- ft ~t~~~- ft ~~~~~- ft ~t~~~- MEYER TOWNHOMES SHORT Pl.AT .,..,.,. iii (WJ G) ~~ ,_,__ A08l65 I -~11:1&, °"--a· Q ' H.H.PHAN ' !E:.:::--~ u'.'"""'" ,,._;:.;;., ~ -·---1ESC DETALS EC2 ~ CITY OF RENTON 10839-SE 173RD STREET RENTON, WA 98055 ..,....,,,__,...,., • • H.H.PHAN Dlllllll -.... -. J ,_.,.,..,.., -•li1/!il NO R£VlllDN Ill' MTE,-. H.H.PHAN I lni KING COUNTY, WASHINGTON. SURFACE WATER DESIGN MANUAL, APPENDIX C C.3 EROSION AND SEDIMENT CONTROL (ESC) MEASURES This section presents the specifications for the kinds of the ESC measures applicable to small project sites as allowed by the County's ESC Standan/s (Detached Appendix D of the King County Surface Water Design Manua[). For projects in Small Project Drainage Review, these measures may be used if no more than 3 acres of soil will be disturbed by the project. Other ESC measures may be allowed or required by DOES if these are inappropriate for the project or fail to contain sediment on the project site. A description of other measures and a more detailed description of those included here can be found in the ESC Standards. Projects that disturb 3 acres or more of soil will require an ESC plan developed by a civil engineer under a Targeted Drainage Review. Intent of ESC Measures The intent of ESC measures is to prevent, to the maximum extent practicable, the transport of sediment and other construction-related pollutants to streams, wetlands, lakes, drainage systems, and adjacent properties during and after construction. Erosion of disturbed areas on construction sites can result in excessive sediment transport to adjacent properties and to surface waters. This sediment can result in major adverse impacts, such as flooding due to obstructed drainage ways, smothering of salmonid spawning beds, creation of algal blooms in lakes, and violation of State water quality standards for turbidity. In addition to sediment, other construction-related pollutants can be generated by uncovered waste materials, stockpiles, and demolition debris; de-watering; maintenance and operation of heavy equipment; chemical spills; oil spills; placement of concrete; and application of fertilizers and pesticides. Such pollutants can be toxic to both fish and humans and may violate State water quality standards and the prohibited discharges section of KCC 9.12. Stabilization of the site after construction and prior to the wet season is also important to preventing these impacts. Organization of Section C.3 The ESC measures in this section are divided into two categories, those used during construction and those used after. Those measures used during construction are referred to as temporary ESC measures while those used after construction are referred to as permanent or final stabilization measures. Thus, the section is organized as follows: • Section C.3.1, "Temporary ESC" (p. C-79) • Section C.3.2, "Final Stabilization" (p. C-90) C.3.1 TEMPORARY ESC Temporary ESC measures are used during construction to minimize the amount of sediment mobilized and trap any mobilized sediment before it leaves the project site. This section presents the requirements and specifications for those temporary ESC measures typically applied to projects in Small Project Drainage Review. They include the following: • "Stabilized Construction Entrance," Section C.3. 1. 1 (p. C-80) • "Mulching," Section C.3.1.2 (p. C-81) • "Nets and Blankets," Section C.3.1.3 (p. C-83) • "Plastic Covering," Section C.3.1.4 (p. C-85) • "Mark Clearing Limits/Minimize Clearing," Section C.3. 1.5 (p. C-86) • "Silt Fence," Section C.3.1.6 (p. C-86) • "Vegetated Strip," Section C.3.1.7 (p. C-88) 2005 Surface Water Design Manual-Appendix C 1/24/2005 C-79 SECTION C.3 EROSION AND SEDIMENT CONTROL (ESC) MEASURES • "Triangular Silt Dike," Section C.3.1.8 (p. C-89) • "Winter Stabilization," Section C.3.1.9 (p. C-90) The above measures must be implemented as needed to prevent the discharge of sediment-laden water from the construction site. Proposed measures must be shown on the small site ESC plan required to be submitted with the small project drainage plans. Site-specific conditions during construction may require additional measures as deemed necessary by ODES. As noted in Section C.3 above, other temporary ESC measures found in Appendix O of the SWDM may be needed or may be more appropriate for the project site as determined by ODES. C.3.1.1 STABILIZED CONSTRUCTION ENTRANCE Purpose l/24/2005 Construction entrances are stabilized to reduce the amount of sediment transported onto paved roads by motor vehicles or runoff by constructing a stabilized pad of quarry spa11s at the entrances to construction sites. Application Construction entrances shall be stabilized wherever traffic will be leaving a construction site and traveling on paved roads or other paved areas within 1,000 feet of the site. Design and Installation Specifications I. See Figure C.3.1.A for details. 2. A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping up into the rock pad. The geotextile shall meet the following standards: Grab Tensile Strength (ASTM 04751) 200 psi min. Grab Tensile Elongation (ASTM 04632) 30% max. Mullen Burst Strength (ASTM 03786-SOa) 400 psi min. AOS (ASTM 04751) 20-45 (U.S. standard sieve size) 3. Hog fuel (wood based mulch) may be substituted for or combined with quarry spalls in areas that will not be used for permanent roads. The effectiveness of hog fuel is highly variable, but it has been used successfully on many construction sites. It generally requires more maintenance than quarry spalls. Hog fuel is not recommended for entrance stabilization in urban areas. The inspector may at any time require the use of quarry spalls if the hog fuel is not preventing sediment from being tracked onto pavement or if the hog fuel is being carried onto pavement. Hog fuel is prohibited in permanent roadbeds because organics in the subgrade soils cause difficulties with compaction. 4. Whenever possible, the entrance shall be constructed on a firm, compacted subgrade. This can substantially increase the effectiveness of the pad and reduce the need for maintenance. Maintenance I. Quarry spalls (or hog fuel) shall he added if the pad is no longer in accordance with the specifications. 2. If the entrance is not preventing sediment from being tracked onto pavement, then alternative measures to keep the streets free of sediment shall be used. This may include street sweeping, an increase in the dimensions of the entrance, or the installation of a wheel wash. If washing is used, it 2005 Surface Water Design Manual-Appendix C C-80 C.3.1 TEMPORARY ESC shall be done on an area covered with crushed rock, and wash water shall drain to a sediment trap or pond. 3. Any sediment that is tracked onto pavement shall be removed immediately by sweeping. The sediment collected by sweeping shall be removed or stabilized onsite. The pavement shall not be cleaned by washing down the street, except when sweeping is ineffective and there is a threat to public safety. If it is necessary to wash the streets, a small sump must be constructed. The sediment would then be washed into the sump where it can be controlled and discharged appropriately. 4. Any quarry spalls that are loosened from the pad and end up on the roadway shall be removed immediately. FIGURE C.3.1.A STABILIZED CONSTRUCTION ENTRANCE AS PER KING COUNTY ROAD STANDARDS, DRIVEWAYS SHALL BE PAVED TO THE EDGE OF R-0-W PRIOR TO INSTALLATION OF THE CONSTRUCTION ENTRANCE TO AVOID DAMAGING OF THE ROADWAY INSTALL DRIVEWAY CULVERT IF THERE IS A ROADSIDE DITCH PRESENT, AS PER KING COUNTY ROAD STANDAROS 4" -8" QUARRY SPALLS - GEOTEXTILE- 12" MIN. THICKNESS C.3.1.2 MULCHING Purpose I IT IS RECOMMENDED THAT THE ENTRANCE BE CROWNED SO THAT RUNOFF DRAINS OFF THE PAD The purpose of mulching soils is to provide immediate temporary protection from erosion. Mulch also enhances plant establishment by conserving moisture, holding fertilizer, seed, and topsoil in place, and moderating soil temperatures. There is an enormous variety of mulches that may be used. Only the most common types are discussed in this section. Conditions of Use As a temporary cover measure, mulch should be used: 1. On disturbed areas that require cover measures for less than 30 days 2. As a cover for seed during the wet season and during the hot summer months 3. During the wet season on slopes steeper than 3H:IV with more than 10 feet of vertical relief. 2005 Surface Water Design Manual -Appendix C 1/24/2005 C-81 I SECTION C.3 EROSION AND SEDIMENT CONTROL (ESC) MEASURES Mulch Material Straw Wood Fiber Cellulose Compost Hydraulic Matrices Design and Installation Specifications For mulch materials, application rates, and specifications, see Table C.3.1.A. Note: Thicknesses may be increased for disturbed areas in or near critical areas or other areas highly susceptible to erosion. Maintenance Standards I. The thickness of the mulch cover must be maintained. 2. Any areas that experience erosion shall be re-mulched and/or protected with a net or blanket. If the erosion problem is drainage related, then the drainage problem shall be assessed and alternate drainage such as interceptor swales may be needed to fix the problem and the eroded area re-mulched. TABLE C.3.1.A MULCH STANDARDS AND GUIDELINES Quality Standards Application Remarks Rates Air-dried; free from 2"-3" thick; 2-3 Cost-effective protection when applied with adequate undesirable seed and bales per 1 000 st thickness. Hand-application generally requires greater coarse material or 2-3 tons per acre thickness than blown straw. Straw should be crimped to avoid wind blow. The thickness of straw may be reduced by halt when used in conjunction with seeding. No growth inhibiting Approx. 25-30 lbs Shall be applied with hydromulcher. Shall not be used factors per 1000 sf or without seed and tackifier unless the application rate is 1000-1500 lbs per at least doubled. Some wood fiber with very long fibers acre can be effective at lower application rates and without seed or tackifier. No visible water or dust 2" thick min.; More effective control can be obtained by increasing during handling. Must approx. 100 tons thickness to 3". Excellent mulch for protecting final be purchased from per acre (approx. grades until landscaping because it can be directly supplier with Solid 800 lbs per cubic seeded or tilled into soil as an amendment. Sources for Waste Handling Permit. yard) compost are available from the King County Commission for Marketing Recyclable Materials at (206) 296-4439. This mulch category Apply at rates from The BFM shall not be applied immediately before, during includes hydraulic 3,000 lbs per acre or immediately after rainfall so that the matrix will have (Bonded Fiber slurries composed of to 4,000 lbs per an opportunity to dry for 24 hours after installation. Matrix) wood fiber, paper fiber acre and based on Application rates beyond 2,500 pounds may interfere or a combination of the manufacturers with germination and are not usually recommended for two held together by a recommendations turf establishment. BFM is generally a matrix where all binding system. The fiber and binders are in one bag, rather than having to BFM shall be a mixture mix components from various manufacturers to create a of long wood fibers and matrix. BFMs can be installed via helicopter in remote various bonding agents. areas. They are approximately $1,000 per acre cheaper to install. Chipped Site Average size shall be 2" minimum This is a cost-effective way to dispose of debris from Vegetation several inches. thickness clearing and grubbing, and it eliminates the problems associated with burning. Generally, it should not be used on slopes above approx. 10% because of its tendency to be transported by runoff. It is not recommended within 200 feet of surface waters. If seeding is expected shortly after mulch, the decomposition of the chipped vegetation may tie up nutrients important to grass establishment. l/24/2005 2005 Surface Water Design Manual -Appendix C C-82 C.3.1.3 NETS AND BLANKETS Purpose C.3.1 TEMPORARY ESC Erosion control nets and blankets are intended to prevent erosion and hold seed and mulch in place on steep slopes and in channels so that vegetation can become well established. In addition, some nets and blankets can be used to permanently reinforce turf to protect drainage ways during high flows. Nets are strands of material woven into an open, but high-tensile strength net (for example, jute matting). Blankets are strands of material that are not tightly woven, but instead form a layer of interlocking fibers, typically held together by a biodegradable or photodegradable netting (for example, excelsior or straw blankets). They generally have lower tensile strength than nets, but cover the ground more completely. Coir (coconut fiber) fabric comes as both nets and blankets. Conditions of Use Erosion control nets and blankets should be used: 1. For permanent stabilization of slopes 2H: 1 V or greater and with more than 10 feet of vertical relief. 2. In conjunction with seed for final stabilization of a slope, not for temporary cover. However, they may be used for temporary applications as long as the product is not damaged by repeated handling. In fact, this method of slope protection is superior to plastic sheeting, which generates high-velocity runoff. 3. For drainage ditches and swales (highly recommended). The application of appropriate netting or blanket to drainage ditches and swales can protect bare soil from channelized runoff while vegetation is established. Nets and blankets also can capture a great deal of sediment due to their open, porous structure. Synthetic nets and blankets may be used to permanently stabilize channels and may provide a cost-effective, environmentally preferable alternative to riprap. Design and Installation Specifications 1. See Figure C.3.1.B and Figure C.3.1.C for typical orientation and installation of nettings and blankets. Note: Installation is critical to the effectiveness of these products. If good ground contact is not achieved, runoff can concentrate under the product, resulting in significant erosion. 2. Jute matting must be used in conjunction with mulch. Excelsior, woven straw blankets, and coir (coconut fiber) blankets may be installed without mulch. There are many other types of erosion control nets and blankets on the market that may be appropriate in certain circumstances. Other types of products will have to be evaluated individually. In general, most nets (e.g., jute matting) require mulch in order to prevent erosion because they have a fairly open structure. Blankets typically do not require mulch because they usually provide complete protection of the surface. 3. Purely synthetic blankets are allowed but shall only be used for Jong-term stabilization of waterways. The organic blankets authorized above are better for slope protection and short-term waterway protection because they retain moi~ture and provide organic matter to the soil, substantially improving the speed and success of re-vegetation. Maintenance Standards 1. Good contact with the ground must be maintained, and there must not be erosion beneath the net or blanket. 2. Any areas of the net or blanket that are damaged or not in close contact with the ground shall be repaired and stapled. 3. If erosion occurs due to poorly controlled drainage, the problem shall be fixed and the eroded area protected. 2005 Surface Water Design Manual -Appendix C 1/2412005 C-83 SECTION C.3 EROSION AND SEDIMENT CONTROL (ESC) MEASURES FIGURE C.3. l.B WATERWAY INSTALLATION DO NOT STRETCH BLANKETS/MATTINGS TIGHT - ALLOW THE ROLLS TO MOLD TO ANY IRREGULARITIES SLOPE SURFACE SHALL BE SMOOTH BEFORE PLACEMENT FOR PROPER SOIL CONTACT ANCHOR, STAPLE, AND INSTALL CHECK SLOTS AS PER MANUFACTURER'S RECOMMENDATIONS AVOID JOINING MATERIAL IN THE CENTER OF THE DITCH LIME, FERTILIZE AND SEED BEFORE INST.A.LlATION MIN. 4" OVERLAP MIN. 6' OVERLAP FIGURE C.3.1.C SLOPE INSTALLATION SLOPE SURFACE SHALL BE SMOOTH BEFORE PLACEMENT FOR PROPER SOIL CONTACT STAPLING PATIERN AS PER MANUFACTURER'S RECOMMENDATIONS DO NOT STRETCH BLANKETS/MATTINGS TIGHT - ALLOW THE ROLLS TO MOLD TO p.JfY IRREGULARITIES FOR SLOPES LESS THAN 3H:1V, ROLLS MAY BE PLACED IN HORIZONTAL STRIPS 1/2412005 C-84 ANCHOR IN 6"x6" MIN. TRENCH AND STAPLE AT 12" INTERVALS LIME, FERTILIZE AND SEED BEFORE INSTALLATION. PLANTING OF SHRUBS, TREES, ETC. SHOULD OCCUR AFTER INSTALLATION. 2005 Surface Water Design Manual -Appendix C C.3.l TEMPORARY ESC C.3.1.4 PLASTIC COVERING Purpose Plastic covering provides immediate, short-term erosion protection to slopes and disturbed areas. Conditions of Use I. Plastic covering may be used on disturbed areas that require cover measures for less than 30 days. 2. Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note: The relatively rapid breakdown of rrwst polyethylene sheeting makes it unsuitable for long-term applications. 3. Clear plastic sheeting may be used over newly-seeded areas to create a greenhouse effect and encourage grass growth. Clear plastic should not be used for this purpose during the summer months because the resulting high temperatures can kill the grass. 4. Due to rapid runoff caused by plastic sheeting, this method shall not be used upslope of areas that might be adversely impacted by concentrated runoff. Such areas include steep and/or unstable slopes. Note: There have been many problems with plastic, usually attributable to poor installation and maintenance. However, the material itself can cause problems, even when correctly installed and maintained, because it generates high-velocity runoff and breaks down quickly due to ultraviolet radiation. In addition, if the plastic is not completely removed, it can clog drainage system inlets and outlets. It is highly recommended that alternatives to plastic sheeting be used whenever possible and that its use be limited. Design and Installation Specifications I. See Figure C.3.1.D for details. 2. Plastic sheeting shall have a minimum thickness of 0.06 millimeters. 3. If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable protection shall be installed at the toe of the slope in order to reduce the velocity of runoff. PROVIDE ENERCY D1SSIPAT10N AT TOE WHEN NEEDED 2005 Surface Water Design Manual -Appendix C FIGURE C.3.1.D PLASTIC COVERING C-85 TIRES, SANDBAGS, a;t EQUI\IALENT MAY BE USED TOWEK31iT PLASTIC SEAMS BETWEEN SHEETS WST OVERLAP A MINIMW OF 12" ANO BE WEIGHTED OR TAPED 1/2412005 SECTION C.3 EROSION AND SEDIMENT CONTROL (ESC) MEASURES Maintenance Standards for Plastic Covering I. Tom sheets must be replaced and open seams repaired. 2. If the plastic begins to deteriorate due to ultraviolet radiation, it must be completely removed and replaced. C.3.1.5 MARK CLEARING LIMITS/MINIMIZE CLEARING Purpose Minimizing clearing is the most effective method of erosion control. Undisturbed vegetation intercepts and slows rainwater. Plant roots hold soil in place, and dead vegetation on the ground acts as a mulch. Applications Clearing limits shall be marked and clearing minimized on any site where significant areas of undisturbed vegetation will be retained. Design Specifications Minimizing clearing should be incorporated into the site design. Clearing limits must be marked on the small site ESC plan. On the ground, clearing limits must be clearly marked with brightly colored tape or plastic or metal safety fencing. If tape is used, it should be supported by vegetation or stakes, and should be about 3 to 6 feet high and highly visible. Equipment operators should be informed of areas of vegetation that are to be left undisturbed. Maintenance Fencing shall be inspected regularly and repaired or replaced as needed. C.3.1.6 SILT FENCE l/2412005 Purpose Use of a silt fence reduces the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use Silt fence may be used downslope of all disturbed areas. Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial amounts of overland flow. Design and Installation Specifications I. See Figure C.3.1.E and Figure C.3.1.F for details. 2. The geotextile used must meet the standards listed below. A copy of the manufacturer's fabric specifications must be available onsite. AOS (ASTM D4751) 30-100 sieve size (0.60-0.15 mm) for slit film 50-100 sieve size (0.30-0.15 mm) for other fabrics Water Permittivity (ASTM D4491) 0.02 sec·' minimum Grab Tensile Strength (ASTM D4632) 180 lbs. min. for extra strength fabric 100 lbs. min. for standard strength fabric Grab Tensile Elongation (ASTM D4632) 30% max. Ultraviolet Resistance (ASTM D4355) 70% min. 2005 Surface Water Design Manual-Appendix C C-86 C.3.1 TEMPORARY ESC 3. Standard strength fabric requires wire backing to increase the strength of the fence. Wire backing or closer post spacing may be required for extra strength fabric if field performance warrants a stronger fence. 4. Where the fence is installed, the slope shall be no steeper than 2H: 1 V. 5. If a typical silt fence (per Figure C.3.1.E) is used, the standard 4 x 4 trench may not be reduced as long as the bottom 8 inches of the silt fence is well buried and secured in a trench that stabilizes the fence and does not allow water to bypass or undennine the silt fence. Maintenance Standards I. Any damage shall be repaired immediately. 2. If concentrated flows are evident uphill of the fence, they must be intercepted and conveyed to a sediment trap or pond. 3. It is important to check the uphill side of the fence for signs of the fence clogging and acting as a barrier to flow and then causing channelization of flows parallel to the fence. If this occurs, replace the fence or remove the trapped sediment. 4. Sediment must be removed when the sediment is 6 inches high. 5. If the filter fabric (geotextile) has deteriorated due to ultraviolet breakdown, it shall be replaced. FIGURE C.3.1.E SILT FENCE JOINTS IN FILTER FABRIC SHAU. BE SPLICED AT POSTS. USE STAPLES, WIRE RINGS, OR EQUIVALENT TO ATIACH FABRIC TO POSTS. FILTER FABRIC --- -lr:,--------:i,-- 1 I 6' MAX. I ---------MINIMUM 4"x4" TRENCH // LJ / \ BACKFILL TRENCH WITH NATIVESOILOR:314~-1.5~ / POST SPACING MAY BE INCREASED WASHED GRAVEL TO 8' IF WIRE BACKING IS USED 2"x4~ WOOD POSTS, STEEL FENCE NOTE: FILTER FABRIC FENCES SHALL BE POSTS, REBAR, OR EQUIVALENT INSTALLED ALONG CONTOUR WHENEVER POSSIBLE 2005 Surface Water Design Manual -Appendix C C-87 1/24/2005 SECTION C.3 EROSION AND SEDIMENT CONTROL (ESC) MEASURES FIGURE C.3.1.F SILT FENCE INSTALLATION AND MAINTENANCE Dig trench Toe-in-fabric Stake Reinforce Monitor Maintain and clean C.3.1.7 VEGETATED STRIP 1/24/2005 Purpose Vegetated strips reduce the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use Vegetated strips may be used downslope of all disturbed areas. Vegetated strips are not intended to treat concentrated flows. nor are they intended to treat substantial amounts of overland flow. Design and Installation Specifications I. The vegetated strip shall consist of a 25-foot minimum width continuous strip of dense vegetation with a permeable topsoil. Grass-covered. landscaped areas are generally not adequate because the volume of sediment overwhelms the grass. Ideally, vegetated strips shall consist of undisturbed native growth with a well-developed soil that allows for infiltration of runoff. 2. The slope within the strip shall not exceed 4H: 1 V. 3. The uphill boundary of the vegetated strip shall be delineated with clearing limits as specified in Section C.3.1.5 (p. C-86). 2005 Surface Water Design Manual -Appendix C C-88 C.3.1 TEMPORARY ESC Maintenance Standards I. Any areas damaged by erosion or construction activity shall be seeded immediately and protected by mulch. 2. If more than 5 feet of the original vegetated strip width has had vegetation removed or is being eroded, sod must be installed. C.3.1.8 TRIANGULAR SILT DIKE Purpose Triangular silt dikes (TSDs) may be used as check dams, for perimeter protection, for temporary soil stockpile protection, for drop inlet protection, or as a temporary interceptor dike. Silt dikes, if attached to impervious surfaces with tack or other adhesive agent may also be used as temporary wheel wash areas, or concrete washout collection areas. Conditions of Use I. May be used for temporary check dams in ditches. 2. May be used on soil or pavement with adhesive or staples. 3. TSDs have been used to build temporary sediment ponds, diversion ditches, concrete washout facilities, curbing, water bars, level spreaders, and berms. Design and Installation Specifications I. TSDs must be made of urethane foam sewn into a woven geosynthetic fabric. 2. TSDs are triangular, 10 inches to 14 inches high in the center, with a 20-inch to 28-inch base. A 2- foot apron extends beyond both sides of the triangle along its standard section of 7 feet. A sleeve at one end allows attachment of additional sections as needed 3. Install TSDs with ends curved up to prevent water from flowing around the ends 4. Attach the TSDs and their fabric flaps to the ground with wire staples. Wire staples must be No. 11 gauge wire or stronger and shall be 200 mm to 300 mm in length. 5. When multiple units are installed, the sleeve of fabric at the end of the unit shall overlap the abutting unit and be stapled. 6. TSDs must be located and installed as soon as construction will allow. 7. TSDs must be placed perpendicular to the flow of water. 8. When used as check dams, the leading edge must be secured with rocks, sandbags, or a small key slot and staples. 9. When used in grass-lined ditches and swales, the TSD check dams and accumulated sediment shall be removed when the grass has matured sufficiently to protect the ditch or swale unless the slope of the swale is greater than 4 percent. The area beneath the TSD check darns shall be seeded and mulched immediately after dam removal. Maintenance Standards I. Triangular silt dikes shall be monitored for performance and sediment accumulation during and after each runoff producing rainfall event. Sediment shall be removed when it reaches one half the height of the silt dike. 2. Anticipate submergence and deposition above the triangular silt dike and erosion from high flows around the edges of the dike/dam. Immediately repair any damage or any undercutting of the dike/dam. 2005 Surface Water Design Manual -Appendix C 1/24/2005 C-89 SECTION C.3 EROSION AND SEDIMENT CONTROL (ESC) MEASURES C.3.1.9 WINTER STABILIZATION Purpose In order to minimize sediment-laden runoff, as much of the bare and disturbed portions of the project site as possible should be covered during any period of precipitation. Once sediment is mobilized, it is much more difficult to effectively control. Application All project sites require winter stabilization between October 1 and April 30 (the wet season). Design Specifications During the above time frame, slopes and stockpiles 3H: 1 V or steeper and with more than 10 feet of vertical rise shall be covered if they are to remain unworked for more than 12 hours. Other disturbed areas shall be covered or mulched according to Table C.3.1.A (p. C-82) if they are to remain unworked for more than two days. Cover material sufficient to cover all disturbed areas shall be stockpiled on the site at the beginning of the wet season. Areas that are to be left unworked during the winter shall be seeded prior to September 23. Maintenance The project site should be inspected weekly and immediately before, during, and after storms. Cover and other erosion control measures shall be repaired and enhanced as necessary to prevent or minimize sediment runoff and transport. C.3.2 FINAL STABILIZATION 1/24/2005 Purpose Final stabilization minimizes sediment-laden runoff from the project site after construction has been completed. Application All sites require final stabilization prior to final construction approval. Design Specifications Prior to final construction approval. the project site shall be stabilized to prevent sediment-laden water from leaving the project site after project completion. All disturbed areas of the project site shall be vegetated or otherwise permanently stabilized. At a minimum, disturbed areas must be seeded and mulched to ensure that sufficient cover will develop shortly after final approval. Mulch without seeding is adequate for small areas to be landscaped before October 1. All permanent surface water facilities (including catch basins, manholes, pipes, ditches, channels, flow control facilities, and water quality facilities) impacted by sedimentation during construction must be cleaned. Maintenance Permanent erosion control is the responsibility of the owner. The project site must be kept stabilized using landscaping, mulch, or other measures to prevent sediment-laden water from leaving the project site and to prevent sediment from being transported onto adjacent properties and roads. 2005 Surface Water Design Manual -Appendix C C-90 Meyer Townhomes Short Plat -DRAFT Technical Information Report The Concept Group Appendix F Maintenance Procedures September 2008 Appendices APPENDIX A MAJNTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 2-INFILTRATION FACILITIES Maintenance Defect or Problem Conditions When Maintenance Is Needed Results Expected When Component Maintenance Is Performed Infiltration Pond Trash & Debris See "Detention Ponds" Table No. 1 See "Detention Ponds" Table No. 1 General Poisonous Vegetation See "Detention Ponds" Table No. 1 See "Detention Ponds" Table No. 1 or Noxious Weeds Contaminants and See "Detention Ponds" Table No. 1 See "Detention Ponds" Table No. 1 Pollution Unmowed See "Detention Ponds" Table No. 1 See "Detention Ponds" Table No. 1 Grass/Ground Cover Rodent Holes See "Detention Ponds~ Table No. 1 See "Detention Ponds" Table No. 1 Insects See "Detention Ponds~ Table No. 1 See "Detention Ponds" Table No. 1 Infiltration Pond Erosion See "Detention Ponds" Table No. 1 See "Detention Ponds" Table No. 1 Side Slopes Infiltration Pond Tree Growth See "Detention Ponds" Table No. 1 See "Detention Ponds" Table No. 1 Emergency Overflow Spillway and Berms over 4 feet in height. Infiltration Pond Rock Missing See "Detention Ponds" Table No. 1 See "Detention Ponds" Table No. 1 Emergency Overflow Spillway Infiltration Facility Sediment A percolation test pit (ponds) or test of facility Sediment is removed and/or facility Storage Area indicates facility is only working at 90%.1 of its is cleaned so that infiltration system designed capabilities. If two inches or more works according to design. Ponds sediment is present, remove. are reseeded if necessary to control erosion. Infiltration Facility Sediment and Debris By visual inspection, little or no water flows Replaced gravel in rock fitter. Rock Filters through filter during heavy rain storms. (If Applicable) Infiltration Facility Sump Filled with Any sediment and debris filling vault to 10% of Clean out sump to design depth. Sump Sediment and Debris depth from sump bottom to bottom of outlet pipe (If Applicable) or obstructing flow into the connector pipe. Infiltration Facility Filled with Sediment Sediment and debris fill bag more than 1 /2 full. Replaced filter bag or redesign Filter Bags and Debris system. (If Applicable) Infiltration Facility Sediment Remove when 6" or more. Sediment cleaned out to designed Pre-settling Ponds pond shape and depth or sediment and Vaults is removed from vault. Ponds are reseeded if necessary to control erosion. Note: Sediment accumulation of more than 0.25 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 dun·ng first 2 years of operation; once a year thereafter. Clean manholes/catch basins, repair damaged inlets/outlets, clean trash racks. 2005 Surface Water Design Manual -Appendix A 1/2412005 A-3 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 5-CATCH BASINS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed General Trash & Debris Trash or debris of more than % cubic foot which No Trash or debris located (Includes Sediment) is located immediately in front of the catch basin immediately in front of catch basin opening or is blocking capacity of the basin by opening. more than 10%. Trash or debris (in the basin) that exceeds 1/J the No trash or debris in the catch depth from the bottom of basin to invert the basin. lowest pipe into or out of the basin. Trash or debris in any inlet or outlet pipe blocking Inlet and outlet pipes free of trash or more than 1/3 of its height. debris. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within the catch basin. gases (e.g., methane). Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Structure Damage to Corner of frame extends more than% inch past Frame is even with curb. Frame and/or Top curb face into the street (If applicable). Slab Top slab has holes larger than 2 square inches Top slab is free of holes and cracks. or cracks wider than Y.. inch (intent is to make sure all material is running into basin). 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 Basin Cracks wider than 1/:. inch and longer than 3 feet, Basin replaced or repaired to design Walls/Bottom any evidence of soil particles entering catch standards. basin through cracks, or maintenance person judges that structure is unsound. Cracks wider than 1/:. inch and longer than 1 foot No cracks more than 1'4 inch wide at at the joint of any inleVoutlet pipe or any the joint of inleUoutlet pipe. evidence of soil particles entering catch basin through cracks. SettlemenU Basin has settled more than 1 inch or has rotated Basin replaced or repaired to design Misalignment more than 2 inches out of alignment. standards. Fire Hazard Presence of chemicals such as natural gas, oil No flammable chemicals present. and gasoline. Vegetation Vegetation growing across and blocking more No vegetation blocking opening to than 10% of the basin opening. basin. Vegetation growing in inlet/outlet pipe joints that No vegetation or root growth is more than 6 inches tall and less than 6 inches present. apart. Pollution Nonflammable chemicals of more than % cubic No pollution present other than foot per three feet of basin length. surface film. Catch Basin Cover Cover Not in Place Cover is missing or only partially in place. Any Catch basin cover is closed open catch basin requires maintenance. Locking Mechanism Mechanism cannot be opened by on Mechanism opens with proper tools. Not Working maintenance person with proper tools. Bolts into frame have less than % inch of thread. Cover Difficult to One maintenance person cannot remove lid after Cover can be removed by one Remove applying 80 lbs. of lift; intent is keep cover from maintenance person. sealing off access to maintenance. Ladder Ladder Rungs Unsafe Ladder is unsafe due to missing rungs, Ladder meets design standards and misalignment, rust, cracks, or sharp edges. allows maintenance person safe access. 1/24/2005 2005 Surface Water Design Manual -Appendix A A-6 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 5-CATCH BASINS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance Is performed Metal Grates Unsafe Grate Grate with opening wider than 7/8 inch. Grate opening meets design (If Applicable) Opening standards. Trash and Debris Trash and debris that is blocking more than 20% Grate free of trash and debris. of grate surface. Damaged or Missing. Grate missing or broken member(s) of the grate. Grate is in place and meets design standards. NO. 6 -DEBRIS BARRIERS (E.G., TRASH RACKS) Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed. General Trash and Debris Trash or debris that is plugging more than 20% Barrier clear to receive capacity of the openings in the barrier. flow. Metal Damaged/Missing Bars are bent out of shape more than 3 inches. Bars in place with no bends more Bars. than :Y.. 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. NO. 7 -ENERGY DISSIPATERS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed. External: Rock Pad Missing or Moved Only one layer of rock exists above native soil in Replace rocks to design standards. Rock area five square feet or larger, or any exposure of native soil. Dispersion Trench Pipe Plugged with Accumulated sediment that exceeds 20% of the Pipe cleaned/flushed so that it Sediment design depth. matches design. Not Discharging Visual evidence of water discharging at Trench must be redesigned or Water Properly concentrated points along trench (normal rebuilt to standards. condition is a "sheet flow" of water along trench). Intent is to prevent erosion damage. Perforations Plugged. Over 1;; of perforations in pipe are plugged with Clean or replace perforated pipe. debris and sediment. Water Flows Out Top Maintenance person observes water flowing out Facility musl be rebuilt or of uDistributor" Catch during any storm less than the design storm or redesigned to standards. Basin. its causing or appears likely to cause damage. Receiving Area Over-Water in receiving area is causing or has No danger of landslides. Saturated potential of causing landslide problems. Internal: Manhole/Chamber Worn or Damaged Structure dissipating flow deteriorates to 1h or Replace structure to design Post. Baffles, Side of original size or any concentrated worn spot standards. Chamber exceeding one square foot which would make structure unsound. 2005 Surface Water Design Manual -Appendix A 1/24/2005 A-7 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 10-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 that exceeds 20% of the Pipe cleaned of all sediment and diameter of the pipe. debris. Vegetation Vegetation that reduces free movement of water All vegetation removed so water through pipes. flows freely through pipes. Damaged Protective coating is damaged; rust is causing Pipe repaired or replaced. more than 50% deterioration to any part of pipe. Any dent that decreases the cross section area Pipe repaired or replaced. of pipe by more than 20%. Open Ditches Trash & Debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20% of the Ditch cleaned/flushed of all design depth. sediment and debris so that it matches design. Vegetation Vegetation that reduces free movement of water Water flows freely through ditches. through ditches. Erosion Damage to See "Detention Ponds" Table No. 1 See ~Detention Ponds~ Table No. 1 Slopes Rock Lining Out of Maintenance person can see native soil beneath Replace rocks to design standards. Place or Missing (If the rock lining. Applicable). NO. 11 -GROUNDS (LANDSCAPING) Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed General Weeds Weeds growlng in more than 20% of the Weeds present in less than 5% of (Nonpoisonous, not landscaped area (trees and shrubs only). the landscaped area. noxious) Safety Hazard Any presence of poison ivy or other poisonous No poisonous vegetation present in vegetation landscaped area. Trash or Litter Paper, cans, bottles, totaling more than 1 cubic Area clear of litter. foot within a landscaped area (trees and shrubs only) of 1,000 square feet. Trees and Shrubs Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than 5% broken which affect more than 25% of the total of total foliage with split or broken foliage of the tree or shrub. limbs. Trees or shrubs that have been blown down or Tree or shrub in place free of injury. knocked over. Trees or shrubs which are not adequately Tree or shrub in place and supported or are leaning over, causing exposure adequately supported; remove any of the roots. dead or diseased trees. 2005 Surface Water Design Manual -Appendix A 1/24/2005 A-9 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ F ACIL!TIES NO. 12 -ACCESS ROADS Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed General Trash and Debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway free of debris which could square feet {i.e., trash and debris would fill up damage tires. one standards size garbage can). Blocked Roadway Debris which could damage vehicle tires (glass Roadway free of debris which could or metal). damage tires. 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 Obstruction removed to allow at 12-foot width for a distance of more than 12 feet least a 12-foot access. or any point restricting access to less than a 10- foot width. Road Surface Settlement, Potholes, When any surface defect exceeds 6 inches in Road surface uniformly smooth with Mush Spots, Ruts deplh and 6 square feet in area. In general, any no evidence of settlement, potholes, surface defect which hinders or prevents mush spots, or ruts. maintenance access. Vegetation in Road Weeds growing in the road surface that are more Road surface free of weeds taller Surface than 6 inches tall and less than 6 inches tall and than 2 inches. less than 6 inches apart within a 400-square foot area. Modular Grid Build-up of sediment mildly contaminated with Removal of sediment and disposal Pavement petroleum hydrocarbons. in keeping with Health Department recommendations for mildly contaminated soils or catch basin sediments. Shoulders and Erosion Damage Erosion within 1 fool 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. 1/24/2005 2005 Surface Water Design Manual -Appendix A A-10 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ F ACILIT!ES NO, 22-BAFFLE OIL/WATER SEPARATOR Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed. Vault Area Monitoring Inspection of discharge water for obvious signs Effluent discharge from vault should of poor water quality. be clear with out thick visible sheen. Sediment Sediment depth in bottom of vault exceeds 6 No sediment deposits on vault Accumulation inches in depth. bottom which would impede flow through the vault and separation efficiency. Trash and Debris Trash and debris accumulation in vault Trash and debris removed from Accumulation (floatables and non-floatables). vault, and inlet/outlet piping. Oil Accumulation Oil accumulations that exceed 1 inch, at the Extract oil from vault by vactoring. surface of the waler Disposal in accordance with state and local rules and regulations. Vault Structure Damage to Wall, Cracks wider than 1h-inch or evidence of soil Vault replaced or repaired to design Frame. Bottom, particles entering the structure through the specifications. and/or Top Slab cracks, or maintenance/inspection personnel determines that the vault is not structurally sound. Damaged Pipe Joints Cracks wider than Yi-inch at the joint of any No cracks more than %-inch wide at inleVoutlet pipe or any evidence of soil particles the joint of the inleVoutlet pipe. entering the vault through the walls. Baffles Damaged Baffles corroding, cracking, warping and/or Repair or replace baffles to showing signs of failure as determined by specifications. maintenance/inspection person. lnlet/OuUet Pipes Trash and Debris Trash and debris accumulation in inlet/outlet Trash and debris removed from Accumulation (floatables and non-floatables). vault, and inlet/outlet piping. Damaged Pipes Inlet or oUllet piping damaged or broken and in Pipe repaired or replaced. need of repair. Access Cover Damaged/Not Cover cannot be opened. Corrosion/deformation Cover repaired to proper working Working of cover. specifications or replaced. Access Ladder Damaged Ladder is corroded or deteriorated, not Ladder replaced or repaired and functioning properly, missing rungs, cracks, and meets specifications, and is safe to misaligned. use as determined by inspection personnel. l/24/2005 2005 Surface Water Design Manual -Appendix A A-18