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HomeMy WebLinkAboutSW3240205_Supplement-EZ Form_20240307 SUPPLEMENT-EZ COVER PAGE !OHMS LOADED i PROJECT INFORMATION 1_Project Name _ Courtyards on the Greenway _ 2 Project Area(ac) _ _ 49.12 _ 3 Coastal Wetland Area(ac) 0 4 Surface Water Area(Sc) _ 0.41 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) 100 8 Will the vegetated setback remain vegetated? Yes 9 If BUA is proposed in the setback,does it meet NCAC 02H.100319(CTd)? Yes 10 Is streambank stabilization proposed on this project? No NUMBER AND TYPE OF SCMs: 11 Infiltration System 12 Bioretention Cell 13 Wet Pond 2 14 Stormwater Wetland 15 Permeable Pavement _ 16 Sand Filter _ 17 Rainwater Harvesting(RWH) _ 18 Green Roof _ 19 Level Spreader-Filter Strip(LS-FS) 20 Disconnected Impervious Surface(DM) 21 Treatment Swale 22 Dry Pond 23 StormFilter 24 Silva Cell 25 Beyfilter 26 Filterra FORMS LOADED DESIGNER CERTIFICATION 27 Name and Title: Andrew Allison,P.E.-Project Manager 28 Organization: Timmons Group 29 Street address: _ 610 East Morehead Street,Suite 250 30 C!t't r,State,Zip: Charlotte,NC,28202 31 Phone number(a): (704)227-1564 32 Email: andrew.allison@timmons.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. Deslaner \\\`\\' l CIA I'!0 y/J// SEAL = Signature of Designer 054749 • .% 4;1'• 41GINEE�.•'�? • F • • ////202-yG ''0/MMMIllIltlt���`\ 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 n/a Wet Pond Wet Pond 5 Total drainage area(_sq ft) 1,990,692 967,032 483,516 6 Onsite drainage area(sa ft) 1,990,692 967,032 483,516 7 Offslte drainage area(sgft) 0 0 0 8 'Total BUA in project(sq ft) 758380 sf 497456 sf 260924 sf New BUA on subdivided lots(subject to 9 permitting)(sq ft) 563601 sf 353848 sf 209753 sf New BUA not on subdivided lots(subject to 10 permitting)(sf) 195933 sf 137749 sf 51171 sf 11 Offsite BUA(sq ft) We n/a n/a 12 Breakdown of new BUA not on subdivided lots. -Parking(sq ft) 7013 sf 7013 sf n/a -Sidewalk(sq ft) 53617 sf 39787 sf 13830 sf -Roof(sg.ft) 10050 sf 3037 sf n/a -Roadway(sq ft) 125253 sf 87912 sf 37341 sf -Future(sq ft) n/a n/a n/a -Other,please specify in the comment box below(sq ft) n/a n/a n/a New infiltrating permeable pavement on 13 subdivided lots(sq ft) n/a n/a n/a New infiltrating permeable pavement not on 14 subdivided lots(sq ft) n/a n/a n/a Existing BUA that will remain(not subject to 15 permitting)(sq ft) 5859 sf 5859 sf n/a 16 Existing BUA that is already permitted(sq ft) n/a n/a n/a 17 Existing BUA that will be removed(sq ft) 31918 sf 31918 sf n/a 18 Percent BUA 38"/0 51% 54% 19 Design storm(inches) - 3.6 in 3.6 in 3.6 in 20 Design volume of SCM(Cu ft) 415412 cf 319550 cf 95852 cf 21 f Calculation method for design volume Surface Area Surface Area Surface Area ADDITIONAL INFORMATION Please use this space to provide any additional information about the 22 drainage area(s): WET POND 1Drainage area number I 1 2 2 Minimum required treatment volume(Cu ft) E gout.MDC FROM 02H.1050 3 Is the SCM sized to treat the SW from all surfaces at build-out? Yes Yes — 4 Is the SCM located away from contaminated soils? Yes Yes &What are the side slopes of the SCM(H:V)? 3:1 31 6 Does the SCM have retaining walls,gabion walls or other engineered No No side slopes? Are the inlets,outlets,and receiving stream protected from erosion 7(10-year storm)? Yes Yes Is there an overflow or bypass for inflow volume in excess of the a design volume? Yes Yes 9 What is the method for dewatering the SCM for maintenance? Drawdown Orifice Pump(preferred) 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 13 If the SCM is on a single family lot,does(will?)the plat comply with 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 _2 Was the SCM designed by an NC licensed professional? Yes Yes • wit e9Np MDC FROM 02H.105.3 18 Sizing method used SA/DA SA/DA 19 Has a stage/storage table been provided in the calculations? Yes Yes _ 20 Elevation of the excavated main pool depth(bottom of sediment 615.50 619.50 removal)(fmsl) 21 Elevation of the main pool bottom(top of sediment removal)(fmsl) 616.00 620.00 22 Elevation of the bottom of the vegetated shelf(fmsl) 622.00 624.00 23 Elevation of the permanent pool(fmsl) 622.50 624.50 24 Elevation of the top of the vegetated shelf(fmsl) 623.00 625.00 25 Elevation of the temporary pool(fmsl) 625.71 828.36 26 Surface area of the main permanent pool(square feet) 38768 14375 27 Volume of the main permanent pool(cubic feet) 148129 cf 22248 cf 28 Average depth of the main pool(feet) 5.12 ft 3.35 ft 29 Average depth equation used Equation 3 Equation 3 30 If using equation 3,main pool perimeter(feet) _ 1026.0 ft 456.0 ft 31 If using equation 3,width of submerged veg.shelf(feet) 5.0 ft 5.0 ft 32 Volume of the forebay(cubic feet) 39583 cf 10559 cf 33 Is this 15-20%of the volume in the main pool? No No 34 Clean-out depth for forebay(inches) 78 in 54 in 35 Design volume of SCM(cu ft) 319560 cf 95852 cf 36 Is the outlet an orifice or a weir? Weir Weir 37 If orifice,orifice diameter(inches) n/a n/a 38 If weir,weir height(inches) n/a n/a 39 If weir,weir length(inches) 48 in 48 in 40 Drawdown time for the temporary pool(days) 4 3 41 Are the inlet(s)and outlet located in a manner that avoids short- 1 Yes Yes ' circuiting? 42 Are berms or baffles provided to improve the flow path? No No 43 Depth of forebay at entrance(inches) 78 in 54 in 44 Depth of foreb y at exit(inches) 72 in 48 in _ 45 Does water flow out of the forebay in a non-erosive manner? Yes Yes 46 Width of the vegetated shelf(feet) 10 ft 10 ft 47 Slope of vegetated shelf(H:V) 10:1 10:1 48 Does the orifice drawdown from below the top surface of the No No permanent pool? 49 Does the pond minimize impacts to the receiving channel from the 1- Yes Yes yr,24-hr storm? Are fountains proposed?(If Y,please provide documentation that 50 MDC(9)is met.) Yes No 51 Is a trash rack or other device provided to protect the outlet system? Yes Yes 52 Are the dam and embankment planted in non-clumping turf grass? Yes Yes 53 Species of turf that will be used on the dam and embankment Hybrid Bermuda Hybrid Bermuda 54 Has a planting plan been provided for the vegetated shelf? Yes Yes ADDIT ONAL INFORMATION 55,Please use this space to provide any additional information about the wet pond(s): 2