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Home My WebLink AboutSW1221002_Supplement-EZ Form_20230928 SUPPLEMENT-EZ COVER PAGE FORMS LOADED PROJECT INFORMATION 1 Project Name Greater Asheville Regional Airport Terminal Modernization 2 Project Area(ac) 43.29 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 1Width 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 I Infiltration System 12 Bioretention Cell 13 Wet Pond 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(DIS) 21 Treatment Swale 2 22 Dry Pond 1 23 StormFilter 24 Silva Cell 25 Bayfilter 26 Filterra FORMS LOADED DESIGNER CERTIFICATION 27 Name and Title: Nathan Hudgens,PE 28 Organization: Gresham Smith 29 Street address: 222 2nd Ave S,STE 1400 30 City,State,Zip: Nashville,TN 37201 31 Phone number(s): 615-770-8155 32 Email: nathan.hudgens@greshamsith.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 �\\\\11111I I Illll//� N CARP '%, �p FE io A SEAL r• Signature of Designer •a 053149 •'17 = J'•• GI N'41E ' ``` 09/21/2023 Seal Date DRAINAGE AREAS 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 5 versions? No CLICK TO LOAD FORM DRAINAGE AREA INFORMATION "PmEntire Site 1 2 3 Dry Detention Pond 4 Type of SCM 1 Swale 3 Swale 4 5 Total drainage area (sq ft) 1885521 243790 57250 46475 6 Onsite drainage area (sq ft) 1885521 243790 57250 46475 7 Offsite drainage area(sq ft) 0 0 0 0 8 Total BUA in project(sq ft) 1493266 sf 215541 sf 11900 sf 36850 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) 15336 sf 33842 sf N/A 36850 sf 11 Offsite BUA(sq ft) N/A N/A N/A N/A 12 Breakdown of new BUA not on subdivided lots: -Parking(sq ft) - - - 33250 sf -Sidewalk(sq ft) - - - - -Roof(sq ft) 15336 sf 22463 sf - - -Roadway(sq ft) - 1299 sf - - -Future(sq ft) N/A - - - -Other, please specify in the comment box below(sq ft) - 10080 sf - 3600 sf 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) 1339930 sf 181699 sf 11900 sf - 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) - - - 28075 sf 18 Percent BUA 28% 55% 21% 79% 19 Design storm(inches) 1.0 in 1.0 in 1.0 in 20 Design volume of SCM (cu ft) 19394 cf 84 cf 131 cf 21 Calculation method for design volume Simple Method Rational Rational ADDITIONAL INFORMATION Please use this space to provide any additional information about the 22 drainage area(s): Dry detention pond 1: 10,080 sf of impervious area added on the airside of the airport is routed to the dry detention pond. Swale 4:concrete surface between retaining walls TREATMENT SWALE 1 Drainage area number 3 4 2 Desi n flow rate of SCM cfs .40 cfs .60 cfs GENERAL MDC FROM 02H .1050 3 Is the SCM sized to treat the SW from all surfaces at build-out? Yes YeG 4 Is the SCM located away from contaminated soils? Yes Yes 5 What are the side slopes of the SCM (H:V)? 4:1 3:1 6 Does the SCM have retaining walls, gabion walls or other No No 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? Other Other 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)? N/A N/A 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 17 Was the SCM desi ned b an NC licensed rofessional? Yes Yes TREATMENT SWALE MDC FROM 02H .1061 18 SHWT elevation (fmsl) 2103 2087 19 Bottom of the treatment swale (fmsl) 2104.00 2103.00 20 Depth of treatment swale (feet) 1 cf 1 cf 21 Is the swale trapezoidal in shape? Yes Yes 22 Width of bottom of swale (feet) 1 ft 1 ft 23 Side slopes of treatment swale (H:V) 4:1 3:1 24 Length of swale (feet) 300 ft 85 ft 25 Flow depth during the 0.75 inch/hour storm (inches) 1 in 1 in 26 Flow velocity during the 0.75 inch/hour storm (feet per second) 2 cfs 2 cfs 27 Hydraulic retention time for swale (minutes) 4 min 4 min 28 Species of grass that will be used Tall Fescue Tall Fescue 29 Will the grass be maintained at an average height of 6 inches? Yes Yes 30 Will the grass not be cut lower than 4 inches? No No 31 Velocity during the 10-year storm (feet per second) 3 ft/s 3 ft/s 32 Is the swale desi ned to non-erosive) ass the 10- ear storm? Yes Yes ADDITIONAL INFORMATION Please use this space to provide any additional information about the 33 treatment swale(s): TrSwale 1 9:44 AM 9/20/2023 DRY POND 1 Drainage area number 1-3& 1-4 2 Minimum required treatment volume(cu ft) 17597 cf GENERAL MDC FROM 02H.1050 3 Is the SCM sized to treat the SW from all surfaces at build-out? Yes 4 Is the SCM located away from contaminated soils? Yes 5 What are the side slopes of the SCM (H:V)? 3:1 6 Does the SCM have retaining walls, gabion walls or other engineered No side slopes? 7 Are the inlets, outlets,and receiving stream protected from erosion Yes (10-year storm)? 8 Is there an overflow or bypass for inflow volume in excess of the Yes design volume? 9 What is the method for dewatering the SCM for maintenance? Drawdown Orifice 10 If applicable,will the SCM be cleaned out after construction? Yes 11 Does the maintenance access comply with General MDC(8)? Yes 12 Does the drainage easement comply with General MDC(9)? N/A 13 If the SCM is on a single family lot, does (will?)the plat comply with N/A General MDC (10)? 14 Is there an O&M Agreement that complies with General MDC(11)? Yes 15 Is there an O&M Plan that complies with General MDC(12)? Yes 16 Does the SCM follow the device specific MDC? Yes 17 Was the SCM designed by an NC licensed professional? Yes DRY POND MDC FROM 02H.1062 18 SHWT elevation (fmsl) 2102.55 19 Elevation of the bottom of the dry pond (fmsl) 2114.1 20 Distance from bottom to SHWT(feet) 13 ft 21 Elevation of the temporary pool during the design storm (feet) 2120 ft 22 Ponding depth of the design storm (feet) 6 ft 23 Will the dry pond be uniformly graded to flow toward the outlet? Yes 24 Is a low flow channel being provided? No 25 Are the inlet(s)and outlet located in a manner that avoids short- Yes circuiting? 26 Will berms or baffles be provided to increase the flow path? No 27 What method of pretreatment will be provided? Forebay 28 Design volume of SCM (cu ft) 19394 29 Diameter of drawdown orifice(in) 2 in 30 Drawdown time for the temporary pool (hours) 40 31 Does the pond minimize impacts to the receiving channel from the 1- Yes yr, 24-hr storm? 32 Is there a small permanent pool near the orifice to prevent clogging? No 33 Will the outlet be designed to prevent clogging? Yes 34 Are the dam and embankment planted in non-clumping turf grass? Yes 35 Species of turf that will be used on the dam and embankment KY Fescue at 5 Ibs/1,000sf 36 Will trees and shrubs be prevented from growing on the dam and Yes embankment? ADDITIONAL INFORMATION Please use this space to provide any additional information about the 37 dry pond(s): Dry Pond 1 9:38 AM 9/21/2023