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HomeMy WebLinkAbout263.20 (replaced 2020)STREET 340'RIGHT-OF-WAY345'350'335'ASPHALT BERM DETAIL 175'170'STREETRIGHT-OF-WAYDRIVEWAY SLOPE PLAN - DRIVEWAY DISPERSION TRENCH DRIVEWAY SLOPE VARIES AND SLOPES TOWARD STREET (<15%) 25' MIN. 700 SQ FT MAX. BETWEEN BERMS, SEE NOTE 1 MIN. 2% CROSS SLOPE 6" MIN. PLAN - SHEET FLOW DISPERSION FROM A DRIVEWAY FLAT TO MODERATELY SLOPING DRIVEWAYS (<15%) 2-4" DRIVEWAY SLOPE CRUSHED ROCK STRIP 2' WIDE BY 4'' THICK MIN. 10' MIN. GENERAL NOTES: 1.MAXIMUM VEGETATED FLOWPATH SLOPE IS 15% FOR ANY 20-FOOT REACH, AND MAY NOT EXCEED 20%. 2.SEE CONSTRUCTION PLANS FOR SPECIFIC PROJECT REQUIREMENTS. DISPERSION TRENCH DETAIL 24'' MIN. UNDISTURBED NATIVE SOIL 2'' X 6'' UNTREATED CEDAR OR RECYCLED PLASTIC BOARD DIAGONAL ASPHALT BERM, SEE NOTE 3 DISPERSION TRENCHCRUSHED ROCK OR GRAVEL 1" DROP 18" MIN. 6" MIN. 3/4" TO 1 1/2" WASHED DRAIN ROCK 6" MIN. PVC PERFORATED PIPE PER ASTM D1784 6'' MIN. 25' VEGETATED FLOWPATH, SEE NOTE 4 10' MIN. 10' VEGETATED FLOWPATH SEGMENT 20' MAX. WIDTH, SEE NOTE 2 NOTES: 1.SEE STD. PLAN 224.00 FOR ALTERNATE DISPERSION TRENCH IF CONTRIBUTING AREA EXCEEDS 700 SF. USE 10 LF OF TRENCH WITH NOTCH BOARD PER 700 SF TO MAX. 50 LF OF TRENCH. 2.20' MAX. WIDTH OF CONTRIBUTING IMPERVIOUS SURFACE FOR SHEET FLOW DISPERSION, UNLESS VEGETATED FLOWPATH IS INCREASED BY 10' FOR EACH ADDITIONAL 20' OF CONTRIBUTING SURFACE AREA. 3.SLOT DRAINS OR ASPHALT BERMS MAY BE USED TO DIRECT RUNOFF TO ROCK PADS OR DISPERSION TRENCHES IN VARIOUS CONFIGURATIONS. LAYOUTS SHOWN ARE ONLY EXAMPLES. 4.IF DISCHARGE IS TOWARD A STEEP SLOPE HAZARD AREA OR A LANDSLIDE HAZARD STEEPER THAN 15%, VEGETATED FLOWPATH MUST BE 50 FEET. NON-WOVEN GEOTEXTILE FOR SEPARATION PER WSDOT SPECIFICATIONS SECTION 9-33.2(1) TABLE 3 25' MIN. BASIC DISPERSION - FLAT/MODERATE SLOPE DRIVEWAYS PUBLIC WORKS DEPARTMENT APPROVED: DATEGregg Zimmerman Public Works Administrator UNLESS OTHERWISE NOTED, DRAWING IS NOT TO SCALE (NTS) STD. PLAN - 263.20 DocuSign Envelope ID: 6EECF5B6-602A-4E4A-B436-A317AA638878 9/28/2018 | 9:45 AM PDT