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Home My WebLink AboutSW3240202_Supplement-EZ Form_20240530 SUPPLEMENT-EZ COVER PAGE FORMS LOADED PROJECT INFORMATION 1 Project Name Rowan 85 Trade Center 2 Project Area(ac) 91.56 3 Coastal Wetland Area(ac) 0 4 Surface Water Area(ac) 1.53 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? Yes 9 If BUA is proposed in the setback,does it meet NCAC 02H.1003(4)(c-d)? Yes 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 3 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 Storm Filter 24 Silva Cell 25 Bayfilter 26 Filterra FORMS LOADED DESIGNER CERTIFICATION 27 Name and Title: Austin Watts,P.E./Vice President 28 Organization: Kimley-Horn and Associates 29 Street address: 200 South Tryon Street,Suite 200 30 City,State,Zip: Charlotte,NC 28202 31 Phone number(s): 704-319-5698 32 Email: Austin.Watts@Kimley-Hom.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 ; o• f Oti:� # SEAL S Signa a of Designer • 030861 • G•-) .........I NE • �•� % ▪ • •'• /V .w;•`ss 05/30/24 Seal Date 1 Is this a high density project? Yes 2 If so,number of drainage areas/SCMs 3 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 • I FORMS LOADED DRAINAGE AREA INFORMATION Entire Site 1 2 3 4 Type of SCM Sand Filter Sand Filter Sand Filter 5 Total drainage area(sq ft) 3988353.6 904741.2 818492.4 1603008 6 Onsite drainage area(sq ft) 3244348.8 904741.2 818492.4 1521115.2 7 Offsite drainage area(sq ft) 81892.8 0 0 81892.8 8 Total BUA in project(sq ft) 2826608 sf 760122 sf 737035 sf 1329451 sf New BUA on subdivided lots(subject to 9 permitting)(sq ft) N/A N/A N/A N/A New BUA not on subdivided lots(subject to 10 permitting)(sf) 2744715 sf 760122 sf 737035 sf 1247558 sf 11 Offsite BUA(sq ft) 81893 sf N/A N/A 81893 sf 12 Breakdown of new BUA not on subdivided lots: -Parking(sq ft) 410160 sf 110280 sf 94800 sf 205080 sf -Sidewalk(sq ft) 17426 sf 5126 sf N/A 12300 sf -Roof(sq ft) 1236600 sf 332640 sf 451980 sf 451980 sf -Roadway(sq ft) 1080529 sf 312076 sf 190255 sf 578198 sf -Future(sq ft) N/A N/A N/A N/A -Other,please specify in the comment box below(sq ft) N/A N/A N/A N/A New infiltrating permeable pavement on 13 subdivided lots(sq ft) N/A N/A N/A N/A New infiltrating permeable pavement not on 14 subdivided lots(sq ft) N/A N/A N/A N/A Existing BUA that will remain(not subject to 15 permitting)(sq ft) N/A N/A N/A N/A 16 Existing BUA that is already permitted(sq ft) N/A N/A N/A N/A 17 Existing BUA that will be removed(sq ft) 7775 sf 7775 sf sf sf 18 Percent BUA 70% 84% 90% 83% 19 Design storm(inches) 1.0 in 1.0 in 1.0 in 20 Design volume of SCM(cu ft) 45584 cf 44016 cf 80673 cf 21 Calculation method for design volume Simple Simple Simple ADDITIONAL INFORMATION Please use this space to provide any additional information about the 22 drainage area(s): 1 Drainage area number 1 2 3 2 Minimum required treatment volume(cu ft) 45584 sf 44016 sf 80673 sf GENERAL MDC FROM 02H.1050 3 Is the SCM sized to treat the SW from all surfaces at build-out? Yes Yes Yes 4 Is the SCM located away from contaminated soils? Yes Yes Yes 5 What are the side slopes of the SCM(H:V)? 3:1 3:1 3:1 6 Does the SCM have retaining walls,gabion walls or other No No Yes engineered side slopes? 7 Are the inlets,outlets,and receiving stream protected from erosion Yes Yes Yes (10-year storm)? 8 Is there an overflow or bypass for inflow volume in excess of the Yes Yes Yes design volume? 9 What is the method for dewatering the SCM for maintenance? Drawdown Orifice Drawdown Orifice Drawdown Orifice 10 If applicable,will the SCM be cleaned out after construction? Yes Yes Yes 11 Does the maintenance access comply with General MDC(8)? Yes Yes Yes 12 Does the drainage easement comply with General MDC(9)? Yes Yes Yes 13 If the SCM is on a single family lot,does(will?)the plat comply with N/A N/A N/A General MDC(10)? 14 Is there an O&M Agreement that complies with General MDC(11)? Yes Yes Yes 15 Is there an O&M Plan that complies with General MDC(12)? No No No 16 Does the SCM follow the device specific MDC? Yes Yes Yes 17 Was the SCM designed by an NC licensed professional? Yes Yes Yes SAND FILTER MDC FROM 02H.1056 18 SHWT elevation(fmsl) 779 775 776.7 19 Type of sand filter(open or closed) Open 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? Yes Yes Yes Sediment Chamber 23 Volume that can be retained in the sediment chamber(cubic feet) 25045 cf 22530 cf 184530 cf 24 Will there be a permanent pool in the sediment chamber? No No No 25 Bottom of the sediment chamber(fmsl) 785.00 786.00 782.00 26 Area of the sediment chamber(square feet) 14831 sf 3645 sf 87960 sf 27 Physical depth of the sediment chamber(inches) 24 in 42 in 24 in 28 Ponding depth in the sediment chamber,above any permanent pool(inches) in in in 29 Elevation of top of weir between chambers(fmsl) 786.5 789.2 783.5 Sand Chamber 30 Volume that can be retained in the sand chamber(cubic feet) 24620 cf 25184 cf 60279 cf 31 Bottom of the sand chamber(fmsl) 782.50 783.50 779.50 32 Area of the sand chamber(square feet) 9393 sf 4125 sf 27895 sf 33 Physical depth of the sand chamber(inches) 54 in 72 in 54 in 34 Ponding depth in the sand chamber,above the sand surface 24 in 42 in 24 in (inches) 35 Elevation of the bypass device(fmsl) 787 789.5 784 36 Type of bypass device Outlet Control Outlet Control Outlet Control Structure Structure Structure 37 Mechanism for distributing flow over the sand surface Riprap Weir Riprap Weir Riprap Weir 38 Sand specification for sand chamber Per ASTM C33 Per ASTM C33 Per ASTM C33 39 Depth above underdrain pipe(inches) 18 in 18 in 18 in 40 Will the media be maintained to drain at least two inches per hour at Yes Yes Yes the sand surface? 41 Is at least one clean-out pipe provided at the low point of each Yes Yes Yes underdrain line? 42 Will clean-out pipes be capped? Yes Yes Yes ADDITIONAL INFORMATION Please use this space to provide any additional information about 43 the sand filter(s): Sand filters were chosen due to the proximity to an airport. Each SCM is designed to attenuate peak flow for the 10-year design storm in addition to the required treatment.