HomeMy WebLinkAbout263.20STREET 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
ROCK STRIP TO BE 2'
WIDE BY MIN. 4'' THICK.
3/4" - 1 1/2" WASHED
DRAIN ROCK OR
GRAVEL BACKFILL FOR
DRYWELLS PER WSDOT
STD. SPECIFICATION
SECTION 9-03.12(5).
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" - 1 1/2" WASHED DRAIN ROCK
OR GRAVEL BACKFILL FOR
DRYWELLS PER WSDOT STD.
SPECIFICATION SECTION 9-03.12(5)
6" DIA. MIN.
PERFORATED PVC,
SDR 35 PER ASTM D3034
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:
DATEMartin Pastucha
Public Works Administrator
UNLESS OTHERWISE NOTED, DRAWING IS NOT TO SCALE (NTS)
STD. PLAN - 263.20
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11/2/2020 | 1:04 PM PST