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Home My WebLink AboutSW3181002_Supplement-EZ Form_20230918 SUPPLEMENT-EZ COVER PAGE FORMS LOADED PROJECT INFORMATION 1 1Project Name Cottages West/Cottages at Indian Trail 2 Project Area(ac) 12.67 3 Coastal Wetland Area(ac) 0 4 Surface Water Area(ac) 0 5 Is this project High or Low Density? High 6 Does this project use an off-site SCM? No COMPLIANCE WITH 02H.1003(4) 7 Width of vegetated setbacks provided(feet) 30 8 Will the vegetated setback remain vegetated? N/A 9 If BUA is proposed in the setback,does it meet NCAC 02H.1003(4)(c-d)? N/A 10 Is streambank stabilization proposed on this project? No NUMBER AND TYPE OF SCMs: 11 Infiltration System 12 Bioretention Cell 13 Wet Pond 14 Stormwater Wetland 15 Permeable Pavement 16 Sand Filter 2 17 Rainwater Harvesting(RWH) 18 Green Roof 19 Level Spreader-Filter Strip(LS-FS) 20 Disconnected Impervious Surface(DIS) 21 Treatment Swale 22 Dry Pond 23 StormFilter 24 Silva Cell 25 Bayfilter 26 Filterra FORMS LOADED DESIGNER CERTIFICATION 27 1Name and Title: Nicholas T.Vesely,PE(Engineer) 28 Organization: V3 Southeast 29 Street address: 2923 S.Tryon St.,Suite 320 30 City,State,Zip: Charlotte,NC,28203 31 Phone number(s): 704.940.2883 32 Email: NVesely@V3Co.com Certification Statement: I certify,under penalty of law that this Supplement-EZ form and all supporting information were prepared under my direction or supervision;that the information provided in the form is,to the best of my knowledge and belief,true,accurate,and complete;and that the engineering plans, specifications,operation and maintenance agreements and other supporting information are consistent with the information provided here. Designer Signature of Designer Seal Date DRAINAGE AREAS 1 Is this a high density project? Yes 2 If so,number of drainage areas/SCMs 2 3 Does this project have low density areas? No 4 If so,number of low density drainage areas 0 Is all/part of this project subject to previous rule 5 versions? No FORMS LOADED DRAINAGE AREA INFORMATION Entire Site 1 2 4 Type of SCM Sand Filter Sand Filter 5 Total drainage area(sq ft) 652,964 292,723 360,241 6 Onsite drainage area(sq ft) 436,459 156,816 279,643 7 Offsite drainage area(sq ft) 216,635 136037 80598 8 Total BUA in project(sq ft) 213008 sf 60548 sf 152460 sf New BUA on subdivided lots(subject to 9 permitting)(sq ft) 153767 sf 38333 sf 115434 sf New BUA not on subdivided lots(subject to 10 permitting)(sf) 59241 sf 22215 sf 37026 sf 11 Offsite BUA(sq ft) 217059 sf 136037 sf 81022 sf 12 Breakdown of new BUA not on subdivided lots: -Parking(sq ft) -Sidewalk(sq ft) 16534 sf 6179 sf 10355 sf -Roof(sq ft) -Roadway(sq ft) 43549 sf 16556 sf 26993 sf -Future(sq ft) -Other,please specify in the comment box below(sq ft) 380 sf 380 sf New infiltrating permeable pavement on 13 subdivided lots(sq ft) _ New infiltrating permeable pavement not on 14 subdivided lots(sq ft) Existing BUA that will remain(not subject to 15 permitting)(sq ft) N/A 16 Existing BUA that is already permitted(sq ft) 17 Existing BUA that will be removed(sq ft) 18 Percent BUA 66% 67% 65% 19 Design storm(inches) 1.0 in 1.0 in 20 Design volume of SCM(cu ft) 14065 cf 22131 cf 21 Calculation method for design volume SCS TR-20 SCS TR-20 ADDITIONAL INFORMATION Please use this space to provide any additional information about the 22 drainage area(s): The drainage areas do not vary greatly from the previous design,however. The 380 sf above indicates the amount of sidewalk that is bypassed around the site. SAND FILTER 1 Drainage area number 1 2 2 Minimum required treatment volume(cu ft) 11975 sf 14460 sf GENERAL MDC FROM 02H.1050 3 Is the SCM sized to treat the SW from all surfaces at build-out? Yco Yeo 4 Is the SCM located away from contaminated soils? Yes Yes 5 What are the side slopes of the SCM(H:V)? 3:1 3:1 6 Does the SCM have retaining walls,gabion walls or other No Yes engineered side slopes? 7 Are the inlets,outlets,and receiving stream protected from erosion Yes Yes (10-year storm)? 8 Is there an overflow or bypass for inflow volume in excess of the Yes Yes design volume? 9 What is the method for dewatering the SCM for maintenance? Drawdown Orifice Drawdown Orifice 10 If applicable,will the SCM be cleaned out after construction? Yes Yes 11 Does the maintenance access comply with General MDC(8)? Yes Yes 12 Does the drainage easement comply with General MDC(9)? Yes Yes If the SCM is on a single family lot,does(will?)the plat comply with 13 N/A N/A General MDC(10)? 14 Is there an O&M Agreement that complies with General MDC(11)? Yes Yes 15 Is there an O&M Plan that complies with General MDC(12)? Yes Yes 16 Does the SCM follow the device specific MDC? Yes Yes 17 Was the SCM designed by an NC licensed professional? Yes Yes SAND FILTER MDC FROM 02H.1056 18 SHWT elevation(fmsl) <668 <650 19 Type of sand filter(open or closed) _ Open Open _ 20 If closed,will the filter will be pre-cast or pour-in-place? 21 If closed,top of grate elevation(fmsl) 22 Is this sand filter designed to attenuate peak flows? No No Sediment Chamber 23 Volume that can be retained in the sediment chamber(cubic feet) 5733 cf 12586 cf 24 Will there be a permanent pool in the sediment chamber? No No 25 Bottom of the sediment chamber(fmsl) 668.00 657.00 26 Area of the sediment chamber(square feet) 1911 sf 5034 sf 27 Physical depth of the sediment chamber(inches) 36 in 30 in 28 Ponding depth in the sediment chamber,above any permanent 36 in 30 in pool(inches) _ 29 Elevation of top of weir between chambers(fmsl) 671 659.5 Sand Chamber 30 Volume that can be retained in the sand chamber(cubic feet) 8332 cf 9545 cf 31 Bottom of the sand chamber(fmsl) 667.00 657.00 32 Area of the sand chamber(square feet) 2777 sf 3278 sf 33 Physical depth of the sand chamber(inches) 36 in 30 in 34 Ponding depth in the sand chamber,above the sand surface 25 in 30 in (inches) 35 Elevation of the bypass device(fmsl) 671 659.5 36 Type of bypass device Outlet Control Outlet Control Structure Structure Rip-rap forebay to Rip-rap forebay to 37 Mechanism for distributing flow over the sand surface act as level act as level spreader spreader 38 Sand specification for sand chamber ASTM C-33 ASTM C-33 39 Depth above underdrain pipe(inches) 12 in 12 in 40 Will the media be maintained to drain at least two inches per hour at Yes Yes the sand surface? 41 Is at least one clean-out pipe provided at the low point of each Yes Yes underdrain line? 42 Will clean-out pipes be capped? Yes Yes ADDITIONAL INFORMATION Please use this space to provide any additional information about 43 the sand filter(s):