HomeMy WebLinkAboutStormwater - D55 - SAND FILTER (PDF) -1.CONTRACTOR SHALL INSTALL SAND FILTER BASINS ACCORDING TO THE APPROVED PLANSAND/OR CONSTRUCTION SPECIFICATIONS.2.PRE-CONSTRUCTION2.1.CONTRACTOR SHALL AVOID COMPACTION OF THE SAND FILTER BASIN AREA TO PRESERVEEXISTING INFILTRATION RATES.2.2.CONTRACTOR SHALL CALL FOR CITY INSPECTIONS AT THE INTERVALS STIPULATED IN THE"DURING CONSTRUCTION INSPECTION CHECKLISTS".3.DURING CONSTRUCTION:3.1.CONTRACTOR SHALL PROVIDE CONSTRUCTION OBSERVATION DURING CONSTRUCTION OFTHE SAND FILTER BASIN TO ENSURE COMPLIANCE WITH THE APPROVED PLANS ANDDESIGN SPECIFICATIONS.3.2.LOOSE MATERIALS SHALL NOT BE STORED ON THE SAND FILTER BASIN AREA.3.3.THE CONTRACTOR SHALL, AT ALL TIMES DURING AND AFTER SYSTEM INSTALLATION,PREVENT SEDIMENT, DEBRIS AND DIRT FROM ANY SOURCE FROM ENTERING THE SANDFILTER SYSTEM.4.GEOTEXTILE LINERS:4.1.GEOTEXTILE LINERS (PERMEABLE OR IMPERMEABLE AS PER PLAN) MAY BE INSTALLEDALONG PERIMETER OF CROSS-SECTION OF THE SAND FILTER CELL.4.2.PERMEABLE GEOTEXTILE LINER SHALL BE PLACED BELOW THE SAND LAYER IN THE SANDFILTER CELL UNLESS THE ALTERNATIVE CROSS-SECTION IS PROVIDED.4.3.WHERE USED, GEOTEXTILE LINERS SHALL BE PLACED IN ACCORDANCE WITHMANUFACTURER'S STANDARDS AND RECOMMENDATIONS. ALL SEAMS AND OPENINGS INTHE LINER SHALL BE SEALED ACCORDING TO MANUFACTURER'S RECOMMENDATIONS ANDSPECIFICATIONS.4.4.WHERE USED, IMPERMEABLE GEOMEMBRANE SHEET / LINER SHALL BE 40 MIL THICK,HIGH-DENSITY POLYETHYLENE DESIGNED SPECIFICALLY FOR FLEXIBLE GEOMEMBRANEAPPLICATIONS. ADJACENT STRIPS OF IMPERMEABLE LINER SHALL OVERLAP A MINIMUM OF18", OR PER MANUFACTURER'S SPECIFICATION.4.5.WHERE USED, CONTRACTOR TO PLACE LINER IN A WAY THAT ENSURES ENOUGH SLACK INTHE LINER TO ALLOW FOR BACKFILL AND SETTLING WITHOUT TEARING THE LINER.5.AGGREGATES:5.1.ALL AGGREGATES SHALL BE ANGULAR, CRUSHED, WASHED ROCK, CLEAN OF DEBRIS ANDWITH NO MORE THAN 1% FINES.5.2.RESERVOIR AGGREGATE SHALL BE GRADATION ASTM #57 OR #67.5.3.DIAPHRAGM AGGREGATE SHOWN IN ALTERNATIVE CROSS-SECTION SHALL BE "PEAGRAVEL", WITH GRADATION ASTM #8, #89 OR #9.5.4.SAND FILTER MATERIAL SHALL BE GRADATION ASTM C33 SAND.6.UNDERDRAIN:6.1.UNDERDRAIN PIPE TO BE PERFORATED OR SLOTTED. PERFORATIONS OR SLOTS TO BESMALLER THAN SURROUNDING AGGREGATE TO ENSURE AGGREGATE DOES NOT FALL INTOOR CLOG THE OPENINGS.6.2.DO NOT WRAP UNDERDRAIN WITH GEOTEXTILE OR SOCK.6.3.UNDERDRAIN PIPE MUST OUTFALL BY GRAVITY AND MUST TIE INTO A STORMWATER PIPE,INLET OR SYSTEM AND THE LOCATION MUST BE APPROVED BY THE CITY. THE UNDERDRAINTIE-IN SHALL MEET ALL REQUIRED PIPE SIZE, TYPES, AND COVER REQUIREMENTS THATMAY APPLY TO PIPING THAT EXTENDS BEYOND THE LIMITS OF THE SAND FILTER CELL ANDENCROACHES INTO PUBLIC RIGHT-OF-WAY OR OTHER PROPERTY.7.OVERFLOW INLET:7.1.AN OVERFLOW INLET OR RISER PIPE SHALL BE PROVIDED.7.2.ALL OVERFLOW RISER PIPE SHALL BE CAPPED WITH A DOME-SHAPED GRATE.7.3.AN EMERGENCY OVERFLOW ROUTE SHALL BE PROVIDED AND THE LOCATION SHALL BEIDENTIFIED ON THE PLANS.8.CLEANOUTS:8.1.PROVIDE CLEANOUTS (AS PER PLAN) TO ALLOW INSPECTION (BY CAMERA) OF THEUNDERDRAIN SYSTEM DURING AND AFTER CONSTRUCTION.8.2.CLEANOUTS SHALL BE PROVIDED AT EACH BEND GREATER THAN OR EQUAL TO 90° ANDEVERY 100' ALONG A STRAIGHT RUN. CLEANOUT SHALL BE INSTALLED PER THE APPROVEDPLANS.8.3.CLEANOUTS SHALL BE A SOLID WALL PVC STRUCTURE FOR ALL VERTICAL SECTIONS WITHFITTINGS TO CONNECT TO DISTRIBUTION AND UNDERDRAIN PIPING MATERIALS, ASREQUIRED.9.FOREBAY:9.1.THE FOREBAY SHALL BE EASILY ACCESSIBLE WITH A HARD SURFACED BOTTOM FORMAINTENANCE PURPOSES.10.LANDSCAPE MATERIALS10.1.CONTRACTOR SHALL NOT PLACE WEED BARRIER ANYWHERE WITHIN THE SAND FILTERBASIN. IF MULCH IS PLACED IN THE SAND FILTER BASIN, IT MUST BE NON-FLOATABLE.10.2.IF MULCH OR COBBLES ARE PLACED IN THE SAND FILTER BASIN, THE MAXIMUMALLOWABLE WATER DEPTH OF 36" AND REQUIRED BASIN VOLUME MUST BE MEASUREDFROM THE TOP SURFACE OF THE MULCH OR COBBLE.10.3.ROLLED TURF OR SOD IS NOT AN ALLOWABLE LANDSCAPE MATERIAL FOR SAND FILTERBASINS.10.4.LANDSCAPE MATERIALS ARE GENERALLY NOT ENCOURAGED TO BE PLACED ON THEBOTTOM OF THE SAND FILTER BASIN. LANDSCAPE PLANTINGS SHALL NOT BE PLACED TOIMPEDE DRAINAGE INTO OR OUT OF THE SAND FILTER BASIN.10.5.TEMPORARY IRRIGATION MAY BE INSTALLED TO ESTABLISH LANDSCAPING OR SEED INTHE SAND FILTER BASIN.NOTES:8" MIN4" MIN DIAMETERPERFORATED PVCUNDERDRAIN1MAXIMUM ALLOWABLEPONDING DEPTH IS 36"FROM THE TOP OF THEMULCH4 MAXNON-FLOATABLEMULCH (AS PERPLAN)3"PONDING DEPTH MUSTNOT EXCEED FLOWLINEELEVATION OF ADJACENTGUTTERFOREBAY IS REQUIRED TOBE PLACED AT ALL INFLOWLOCATIONS; WITH AMINIMUM 3" DROP FROMGUTTER FLOWLINE TOFOREBAY8" MIN DEPTH OFRESERVOIR AGGREGATE18" MIN DEPTH OFSAND FILTER MATERIAL8" MIN DEPTH THICKENEDCURB ADJACENT TOVEHICULAR PAVEMENTSSTANDARD CROSS-SECTION8"PERMEABLE GEOTEXTILETO BE PLACED BETWEENAGGREGATE LAYERSOVERFLOWRISER OPTION(AS PER PLAN)36" MAX18"8"4"30" MINPONDING DEPTHALTERNATIVE CROSS-SECTION8" MIN DEPTH OFRESERVOIR AGGREGATE18" MIN DEPTH OFSAND FILTER MATERIAL4" MIN DEPTH OFDIAPHRAGM AGGREGATENOTE:THE ALTERNATIVE CROSS-SECTIONS SHOWS A 4"DIAPHRAGM AGGREGATE LAYER INSTEAD OF THEGEOTEXTILE FABRIC, WHICH IS THE ONLY DIFFERENCE FROMTHE STANDARD CROSS-SECTION. ALL OTHER REQUIREMENTSOF THE STANDARD CROSS-SECTION ARE REQUIRED.18" MINFLAT2" MINGEOTEXTILE LINEROPTION (AS PER PLAN)26" MINNATIVE SOILZONEAPPROVED:DRAWN BY:DETAILSCONSTRUCTIONDATE REVISED:DETAILSTORMWATERSAND FILTERDECEMBER 2018HEMD-55