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Home My WebLink AboutSW5200602_Supplement-EZ Form_20201106 DRAINAGE AREAS 1Is this a high density project?Yes ge areas/SCMs2 2 If so, number of draina Is all/part of this project subject to previous rule 3versions?No FORMSLOADED Entire Site12 DRAINAGE AREA INFORMATION 4T ype of SCM Sandfilter/LS-FSSandfilter/LS-FS 5Total BUA in project (sq ft)621370 sf144687 sf49349 sf New BUA on subdivided lots (subject to 6permitting)(sq ft) New BUA outside of subdivided lots (subject to 7permitting) (sf)194036 sf144687 sf40758 sf (sq ft)10962 sf 8Offsite - total area 9Offsite BUA (sq ft)8591 sf 10Breakdown of new BUA outside subdivided lots: - Parking (sq ft) - Sidewalk (sq ft)1448 sf1448 sf - Roof (sq ft)9504 sf2163 sf7341 sf - Roadway (sq ft) - Future (sq ft) - Other, please specify in the comment box below (sq ft) 174493 sf141076 sf33417 sf New infiltrating permeable pavement on 11subdivided lots (sq ft) New infiltrating permeable pavement outside of 12subdivided lots (sq ft) Exisitng BUA that will remain (not subject to 13permitting) (sq ft)427334 sf 14Existing BUA that is already permitted (sq ft) 15Existing BUA that will be removed (sq ft)3289 sf 16Percent BUA47%57%53% 17Design storm (inches)1 in1 in 18Design volume of SCM (cu ft)8935 cf2985 cf Calculation method for design volumesimple methodsimple method 19 ADDITIONAL INFORMATION Please use this space to provide any additional information about the 20drainage area(s): gravel and concrete pads.. SAND FILTER Drainage area number12 1 Design volume of SCM (cu ft)8935 sf2985 sf 2 GENERAL MDC FROM 02H .1050 Is the SCM sized to treat the SW from all surfaces at build-out?YesYes 3 Is the SCM located away from contaminated soils?YesYes 4 What are the side slopes of the SCM (H:V)?3:13:1 5 Does the SCM have retaining walls, gabion walls or other engineered side slopes? NoNo 6 Are the inlets, outlets, and receiving stream protected from erosion (10- year storm)?YesYes 7 Is there an overflow or bypass for inflow volume in excess of the design volume?YesYes 8 What is the method for dewatering the SCM for maintenance?Drawdown OrificeDrawdown Orifice 9 If applicable, will the SCM be cleaned out after construction?YesYes 10 Does the maintenance access comply with General MDC (8)?YesYes 11 Does the drainage easement comply with General MDC (9)?YesYes 12 If the SCM is on a single family lot, does (will?) the plat comply with General MDC (10)?NoNo 13 Is there an O&M Agreement that complies with General MDC (11)?YesYes 14 Is there an O&M Plan that complies with General MDC (12)?YesYes 15 Does the SCM follow the device specific MDC?YesYes 16 Was the SCM designed by an NC licensed professional?YesYes 17 SAND FILTER MDC FROM 02H .1056 SHWT elevation (fmsl)< 433.5< 425.5 18 Type of sand filter (open or closed)OpenOpen 19 If closed, will the filter will be pre-cast or pour-in-place? 20 If closed, top of grate elevation (fmsl) 21 Is this sand filter designed to attenuate peak flows? YesYes 22 Sediment Chamber Volume that can be retained in the sediment chamber (cubic feet)9541 cf5657 cf 23 Will there be a permanent pool in the sediment chamber?NoNo 24 442.00446.00 Bottom of the sediment chamber (fmsl) 25 Area of the sediment chamber (square feet)7603 sf4491 sf 26 Physical depth of the sediment chamber (inches)24 in24 in 27 Ponding depth in the sediment chamber, above any permanent pool (inches)24 in24 in 28 Elevation of top of weir between chambers (fmsl)444448 29 Sand Chamber Volume that can be retained in the sand chamber (cubic feet)10816 cf6981 cf 30 Bottom of the sand chamber (fmsl)439.50443.50 31 4598 sf1500 sf Area of the sand chamber (square feet) 32 Physical depth of the sand chamber (inches)54 in54 in 33 Ponding depth in the sand chamber, above any permanent pool (inches)24 in24 in 34 Elevation of the bypass device (fmsl)444448 35 Type of bypass deviceConc Box RiserConc Box Riser 36 Mechanism for distributing flow over the sand surfaceRiprap WeirsRiprap Weirs 37 Sand specification for sand chamberASTM C-33ASTM C-33 38 Depth above underdrain pipe (inches)18 in18 in 39 Will the media be maintained to drain at least two inches per hour at the sand surface?YesYes 40 Is at least one clean-out pipe provided at the low point of each underdrain line?YesYes 41 Will clean-out pipes be capped? YesYes 42 ADDITIONAL INFORMATION Please use this space to provide any additional information about the Sand Filter(s): 43 sediment chamber bottom is slight wedge Sand Filter11:28 PM 11/6/2020 LEVEL SPREADER - FILTER STRIP (LS-FS) Drainage area number12 1 Design volume of SCM (cu ft)8935 cf2559 cf 2 GENERAL MDC FROM 02H .1050 Is the SCM sized to treat the SW from all surfaces at build-out?YesYes 3 Is the SCM located away from contaminated soils?YesYes 4 What are the side slopes of the SCM (H:V)?20:120:1 5 Does the SCM have retaining walls, gabion walls or other engineered side slopes? NoNo 6 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)?YesYes 7 Is there an overflow or bypass for inflow volume in excess of the design volume?YesYes 8 What is the method for dewatering the SCM for maintenance?OtherOther 9 If applicable, will the SCM be cleaned out after construction?YesYes 10 Does the maintenance access comply with General MDC (8)?YesYes 11 Does the drainage easement comply with General MDC (9)?YesYes 12 If the SCM is on a single family lot, does (will?) the plat comply with General MDC (10)?NoNo 13 Is there an O&M Agreement that complies with General MDC (11)?YesYes 14 Is there an O&M Plan that complies with General MDC (12)?YesYes 15 Does the SCM follow the device specific MDC?YesYes 16 Was the SCM designed by an NC licensed professional?YesYes 17 LS-FS MDC FROM 02H .1059 Length of level spreader (feet)40 ft20 ft 18 Does the LS-FS receive flow from the drainage area or another SCM?YesYes 19 Flow rate to LS-FS during design storm (cfs)3 cfs1 cfs 20 Is a bypass device provided?NoNo 21 If yes, what is the bypass device? 22 Is this LS-FS designed to receive flow from the drainage area during the 10-year storm? 23 Has a blind swale been provided?YesYesYes 24 Does the blind swale provide for uniform overtopping of the level spreader?YesYes 25 What material will be used for the level spreader?concreteconcrete 26 Will the construction tolerance be < 0.25 inch along the level spreader length?YesYes 27 Will the level spreader be straight or convex in plan view?YesYes 28 Height of the drop from the level spreader to the transition zone (inches)3 in3 in 29 Width of the transition zone (inches)36 in36 in 30 Protection for the transition zoneAggregateAggregate 31 Width of the filter strip (feet)30 ft30 ft 32 Is the filter strip free of draws and channels?YesYes 33 Has this been verified in the field?YesYes 34 Slope of the filter strip (%)5%5% 35 Is this slope uniform across the entire filter strip?YesYes 36 Will the first 12" of soil be adjusted if needed to promote plant growth?NoNo 37 Will the filter strip and side slopes be planted with non-clumping, deep-rooted sod?YesYes 38 Species of sod that will be usedcommon bermudacommon bermuda 39 Will soil be temporarily stabilized until permanent vegetation is established?YesYes 40 ADDITIONAL INFORMATION Please use this space to provide any additional information about the level spreader-filter strip(s): 41 LS-FS31:20 PM 10/19/2020