HomeMy WebLinkAbout262.10NOTES:
1.AVOID COMPACTION OF EXISTING SUBGRADE BELOW BASIN.
2.SCARIFY SUBGRADE TO A DEPTH OF 3 INCHES MINIMUM IMMEDIATELY PRIOR TO PLACEMENT OF BIORETENTION SOIL MIX AND UNDERDRAIN AGGREGATE,
EXCEPT WHEN LINER IS REQUIRED.
3.LINER TO BE INSTALLED ONLY WHEN REQUIRED IN THE CITY OF RENTON SURFACE WATER DESIGN MANUAL (RENTON SWDM). LOW PERMEABILITY LINER TO
BE 30 MIL MIN. GEOMEMBRANE LINER OR 12 INCHES MIN. (DRY) CLAY LINER. CLAY LINER TO BE COMPACTED TO 95% MINIMUM DRY DENSITY (ASTM D698),
WITH AT LEAST 30% CLAY PARTICLES PASSING (ASTM D422) AND AT LEAST 15% PLASTICITY INDEX (ASTM D4318).
4.UNDERDRAIN TO BE 6" MIN. (PRIVATE), 8" MIN. (PUBLIC) SLOTTED PVC, SDR 35 PER ASTM D3034. SLOTS SHOULD BE CUT PERPENDICULAR TO THE LONG AXIS
OF THE PIPE AND BE 0.04 TO 0.069 INCHES BY 1 INCH LONG AND BE SPACED 0.25 INCHES APART (SPACED LONGITUDINALLY). SLOTS SHOULD BE ARRANGED
IN FOUR ROWS SPACED ON 45-DEGREE CENTERS AND COVER 1/2 OF THE CIRCUMFERENCE OF THE PIPE. SLOPE PIPE AT 0.5% MIN UNLESS OTHERWISE
SPECIFIED. PROVIDE ONE CLEANOUT MIN. PER 100 FEET OF UNDERDRAIN, AND AT EACH END. SEE STD. PLAN 226.00. MATCH CROWN ELEVATION OF
UNDERDRAIN TO OVERFLOW PIPE UNLESS OTHERWISE SPECIFIED.
5.18" MIN. BIORETENTION SOIL MIX ON BOTTOM AND SIDES TO TOP OF PONDING AREA. BIORETENTION SOIL MIX TO MEET STD. PLAN 262.60.
6.UNDERDRAIN AGGREGATE TO MEET GRAVEL BACKFILL FOR DRAINS PER WSDOT STD. SPECIFICATION SECTION 9-03.12(4).
7.ARBORIST WOOD CHIP MULCH TO MEET STD. PLAN 262.60.
8.MAXIMUM LONGITUDINAL SLOPE (ALONG DIRECTION OF FLOW) OF BIORETENTION SWALES SHALL BE 6%.
9.WHERE NOT CONFLICTING WITH REQUIRED CLEARANCES OR UTILITIES, TREES MAY BE LOCATED IN BIORETENTION. REDUCE BOTTOM WIDTH TO 6 INCHES
MINIMUM AND INCREASE SIDE SLOPE TO 1.5H:1V ADJACENT TO TREE. TREES TO BE LOCATED ONLY OUTSIDE OF LINER FOR LINED FACILITIES.
2%
1
2.5 MIN.
1
2.5 MIN.
1.5
1
GENERAL NOTES:
1.MINIMUM UTILITY SETBACKS AND PROTECTION MEASURES MUST CONFORM TO CURRENT CITY STANDARDS, STD. PLANS 265.00, 265.10, AND 265.20, AND
OTHER UTILITY PROVIDER REQUIREMENTS. COORDINATE WITH CITY ENGINEER IN THE EVENT OF UTILITY CROSSINGS OR CONFLICTS.
2.BSM PLACEMENT, GRADING, AND CONSOLIDATION SHALL NOT OCCUR WHEN THE BSM IS EXCESSIVELY WET OR HAS BEEN SUBJECTED TO MORE THAN
1/2" OF PRECIPITATION WITHIN 48 HOURS PRIOR TO PLACEMENT. EXCESSIVELY WET IS DEFINED AS BEING AT OR ABOVE 22% SOIL MOISTURE BY A
GENERAL TOOLS AND INSTRUMENTS DSMM500 PRECISION DIGITAL SOIL MOISTURE METER WITH PROBE (OR EQUIVALENT). THERE SHOULD BE NO
VISIBLE FREE WATER IN THE MATERIAL. THE CONTRACTOR SHALL PLACE BSM LOOSELY WITH A CONVEYOR BELT OR WITH AN EXCAVATOR OR LOADER
FROM A HEIGHT NO HIGHER THAN 6 FEET, UNLESS OTHERWISE APPROVED BY THE ENGINEER (I.E., DO NOT DUMP MATERIAL DIRECTLY FROM TRUCK
INTO CELL). COMPACT BSM USING NON-MECHANICAL COMPACTION METHODS (E.G., BOOT PACKING, HAND TAMPING, OR WATER CONSOLIDATION) TO
83% (± 2%) OF THE MAXIMUM DRY DENSITY PER MODIFIED PROCTOR TEST (ASTM D1557), OR AS DIRECTED BY THE ENGINEER.
3.SEE CONSTRUCTION PLANS FOR SPECIFIC PROJECT REQUIREMENTS.
ANGLE OF REPOSE
SCARIFIED AND UNCOMPACTED SUBGRADE,
SEE NOTES 1 AND 2
OVERFLOW STRUCTURE PER STD. PLAN
262.40 UNLESS SPECIFIED OTHERWISE
1"
6"
2"-12" PONDING
DEPTH
18" MIN.
BOTTOM WIDTH
MIN. 18"
6" MIN.
FREEBOARD
FOR EDGE TREATMENT OPTIONS,
SEE STD. PLAN 262.20
ROADWAY OR
PARKING LOT
TRANSITION ZONE SOIL,
SEE STD. PLAN 262.20
2"-4" DEPTH ARBORIST
WOOD CHIP MULCH,
SEE NOTE 7
DESIGNER TO SPECIFY WATER STORAGE ELEVATION
TOP OF BANK
ELEVATION
OVERFLOW TO STORM MAIN
LOW PERMEABILITY LINER
WHEN REQUIRED, SEE NOTE 3
GRAVEL BASE, SEE STD. PLAN 262.40
12" MIN.
UNDERDRAIN AGGREGATE,
SEE NOTE 6
UNDERDRAIN, SEE NOTE 4
BIORETENTION SOIL MIX (BSM),
SEE NOTE 5
SIDE SLOPE AT TREE, SEE NOTE 9
SIDEWALK, LANDSCAPING,
DRIVEWAY, OR PAVEMENT
SEE STD.
PLAN
262.20 SEE STD.
PLAN
262.20
BIORETENTION SECTION
(WITH UNDERDRAIN)
STD. PLAN - 262.10
PUBLIC WORKS
DEPARTMENT
APPROVED:
DATEMartin Pastucha
Public Works Administrator
UNLESS OTHERWISE NOTED, DRAWING IS NOT TO SCALE (NTS)
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11/2/2020 | 1:04 PM PST