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Home My WebLink AboutSW1210901_Supplement-EZ Form_20220405DRAINAGE AREAS 1 Is this a high density project? Yes 2 If so, number of drainage areas/SCMs 1 3 Is all/part of this project subject to previous rule versions? No FORMS LOADED DRAINAGE AREA INFORMATION Entire Site 1 4 Type of SCM Dry Pond 5 Total BUA in project (sq ft 18774 sf 6 New BUA on subdivided lots (subject to permitting) (sq ft) sf 7permitting) New BUA outside of subdivided lots (subject to sf 18774 sf 8 Offsite - total area (sq ft) sf 9 Offsite BUA (sq ft sf 10 Breakdown of new BUA outside subdivided lots: -Parking s ft 18774 sf Sidewalk (sq ft sf Roof (sq ft sf Roadway s ft sf Future (sq ft sf Other, please specify in the comment box below (sq ft sf 11 New infiltrating permeable pavement on subdivided lots (sq ft sf 12 New infiltrating permeable pavement outside of subdivided lots (sq ft sf 13permitting) Exisitng BUA that will remain (not subject to s ft sf 14 Existing BUA that is already permitted (sq ft sf 15 Existina BUA that will be removed (sq ft sf 16 Percent BUA 67% 17 1 Design storm inches 3 in 18 1 Design volume of SCM cu ft 3684 cf 19 ICalculation method for design volume SCS method ADDITIONAL INFORMATION Please use this space to provide any additional information about the 20 drainage area(s): According to Appendix E-4 of the NCDEQ Stormwater Design Manual, the dry pond was designed to drawn down in 40 hours rather than 48 hours because this is an airport project and permanent pooling must be avoided. DRAINAGE AREA INFORMATION Entire Site 1 4 Type of SCM Dry Pond 5 Total BUA from project (sq ft 18774 sf 6 1995 rules SL 2006-246 2008 rules 2017 rules New BUA on subdivided lots (subject to ermittin ) (sq ft) 1995 rules SL 2006-246 7 sf 2008 rules 2017 rules 8 New BUA outside of subdivided lots (subject to rmittin sf 18774 sf 1995 rules SL 2006-246 2008 rules 2017 rules 9 Offsite -total area (sq ft sf 1995 rules SL 2006-246 2008 rules 2017 rules 10 Offsite BUA s ft sf 1995 rules SL 2006-246 2008 rules 2017 rules 11 Design storm inches 1 in 1995 rules SL 2006-246 2008 rules 2017 rules 12 Breakdown of new BUA: Parking (sq ft 18774 sf Sidewalk (sq ft Roof (sq ft Roadway s ft Future (sq ft) Other, please specify in the comment box below (sq ft 13 New infiltrating permeable pavement on subdivided lots (sq ft sf 14 New infiltrating permeable pavement outside of Isubdivided lots (sq ft sf 15permitting) Exisitng BUA that will remain (not subject to s ft sf 16 Existing BUA that is already permitted (sq ft sf 17 Existing BUA that will be removed (sq ft sf 18 Percent BUA 67% 19 Design volume of SCM cu ft 3684 cf 20 lCalculation method for design volume Simple Method ADDITIONAL INFORMATION 21 Please use this space to provide any additional information about the drainage area(s): DRY POND 1 1Drainage area number 1 2 IDesign volume of SCM (cu ft) c 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 side slopes? No 7 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? Yes 8 Is there an overflow or bypass for inflow volume in excess of the design volume? Yes 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)? Yes 13 If the SCM is on a single family lot, does (will?) the plat comply with General MDC (10)? No 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 SCIVI designedy an NC licensed professional? Yes DRY POND MDC FROM 02H .1062 18 SHWT elevation (fmsl) unknown 19 Elevation of the bottom of the dry pond (fmsl) 2154 20 Distance from bottom to SHWT (feet) >3ft 21 Elevation of the temporary pool during the design storm (feet) 2155 ft 22 Ponding depth of the design storm (feet) 1 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-circuiting? Yes 26 Will berms or baffles be provided to increase the flow path? No 27 What method of pretreatment will be provided? Gravel and grass strip 28 Diameter of drawdown orifice (in) .8 in 29 Drawdown time for the temporary pool (hours) 40 30 Does the pond minimize impacts to the receiving channel from the 1-yr, 24-hr storm? Yes 31 Is there a small permantent pool near the orifice to prevent clogging? No 32 Will the outlet be designed to prevent clogging? Yes 33 Are the dam and embankment planted in non- clumping turf grass? Yes 34 Species of turf that will be used on the dam and embankment Fescue 35 Will trees and shrubs e prevented from growing on the dam and embankment? Yes ADDITIONAL INFORMATION Please use this space to provide any additional 36 linformation about the infiltration system(s): There is no permanent pool proposed in the SCM, this is Dry Pond 4 3:10 PM 4/1/2022