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Home My WebLink AboutSW6210901_Supplement-EZ Form_20210908SUPPLEMENT-EZ COVER PAGE FORMS LOADED PROJECT INFORMATION — 1 Project Name Gates Farm Subdivision 2 Project Area ac _ 16.75 3 Coastal Wetland Area (ac) 4 Surface Water Area (ac 5 1 Is this project High or Low Density? High 6 IDoes this project use an off -site SCM? No COMPLIANCE WITH 02H ,1008 4 7 Width of vegetated setbacks provided (feet) N/A 8 Will the vegetated setback remain ve etated? NIA 9 If BUA is proposed in the setback, does it meet NCAC 02H.1003 4 c-d ? No 10 Is streambank stabilization proposed on this project? No NUMBER AND TYPE OF SCMs: 77 —11 Infiltration System 0 12 Bioretention Cell 0 13 Wet Pond 1 14 Stormwater Wetland 0 15 Permeable Pavement 0 16 Sand Filter 0 17 Rainwater Harvesting RWH 0 18 Green Roof 0 19 Level Spreader -Filter Strip LS-FS 0 20 Disconnected Impervious Surface (DIS) 0 21 22 _ _ Treatment Swale 0 Dry Pond 0 23 StormFilter 0 24 Silva Cell 0 25 Bayfilter 0 26 Filterra 0 FORMS LOADED DESIGNER CERTIFICATION 27 Name and Title: Organization: Matthew E. Lowder, PE 28 Triangle Site Design, PLLC _ 29 Street address: 4004 Barrett Drive, Suite 101 30 City, State, Zip: Raleigh. NC 27609 31 Phone number(s): 919-553-6570 32 Email: mlowder@trianglesitedesign.com Certification. Statement: I certify, under penalty of law that this Supplement FZ form and all supporting information were prepared under my direction or supervision; that the information provided in the form is, to the hest of my knowledge and relief, 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. F,,,��, trfllr11`'., 4' J 0 SQr��S51a��P9 a SEAL i 2443 �� 9 ENGINE ■■` ` .,r �,W ,P"fl,11rt6A�atff� Signatu of Designer Date DRAINAGE AREAS 1 Is this a high densit l ro'ect? Yes 2 If so, number of drainage areas/SCMs 1 3 Does this project have low density areas? No 4 If so, number of low density drainage areas 0 5 Is all/part of this project subject to previous rule versions? No FORMS LOADED DRAINAGE AREA INFORMATION Entire Site 1 4 Type of SCM - Infiltration Basin 5 Total drainage area (sq ft 759165 sf 689291 6 Onsite drainage area (sq ft 759165 sf 689291 7 Offsite drainage area (sq ft 8 Total BUA in project (sq ft 305418 sf 305418 sf 9 New BUA on subdivided lots (subject to permitting) (sq ft 10permitting) New BUA not on subdivided lots (subject to s 11 Offsite BUA (sq ft 12 Breakdown of new BUA not on subdivided lots: Parkinq (sq ft Sidewalks ft 19503 sf 19503 sf Roof (sq ft 203000 sf 203000 sf Roadway s ft 82915 sf 82915 sf Future (sq ft Other, please specify in the comment box below (sq ft 13 New infiltrating permeable pavement on subdivided lots (sq ft 14 New infiltrating permeable pavement not on Isubdivided lots (sq ft 15permitting) Existing BUA that will remain (not subject to s ft 16 Existing BUA that is already permitted (sq ft 17 Existing BUA that will be removed (sq ft 18 Percent BUA 44% 19 Desi n storm inches 1.0 in 20 Design volume of SCM cu ft 25778 cf 21 lCalculation method for design volume Simple Method ADDITIONAL_ INFORMATION 22 Please use this space to provide any additional information about the 1drainage area(s): WET POND 1 Drainage area number 3 2 1 Minimum required treatment volume cu ft 25778 cf GENERAL MDC FROM 02H .1 0 31 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 en ineered side slopes? No 7 Are the inlets, outlets, and receiving stream protected from erosion 10- ear 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 clewatering the SCM for maintenance? Pump referred 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 ? N/A 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 devicespecific MDC? Yes 17 Was the SCM designed by an NC licensedprofessional? Yes WET POND MDC FROM WM .1053 18 Sizing method used SAIDA 19 Has a sta a/stora a table been provided in the calculations? Yes _ 20 Elevation of the excavated main pool depth (bottom of sediment removal) (fmsl) 291.00 21 Elevation of the main pool bottom (top of sediment removal) (fmsl) 292.00 22 Elevation of the bottom of the vegetated shelf fmsl 294.90 23 Elevation of the permanent pool fmsl 295.40 24 Elevation of the top of the vegetated shelf fmsl 295.90 25 Elevation of the temporary pool fmsl 296.40 26 Surface area of the main permanent pool (square feet 17670 27 Volume of the main permanent pool cubic feet 49005 cf 28 Average depth of the main pool (feet) 3.08 ft 29 1 Average depth euation used Equation 3 30 If using equation 3, main pool perimeter (feet) 640.0 ft 31 If using equation 3, width of submerged veg. shelf (feet) 3.0 It 32 Volume of the foreba (cubic feet) 8947 cf 33 Is this 15-20% of the volume in the mainpool? Yes 34 Clean -out depth for foreba inches 22.8 in 35 Design volume of SCM (cu ft) 25778 cf 36 Is the outlet an orifice or a weir? Orifice 371 If orifice, orifice diameter inches 2.50 in 38 If weir, weir height (inches) 39 If weir, weir length (inches 40 Drawdown time for the tempospool (days) 2.47 41 Are the inlet(s) and outlet located in a manner that avoids short- circuiting? Yes 42 Are berms or baffles provided to improve the flowpath? Yes 43 Depth of forebay at entrance (inches) 34.8 in 44 Depth of forebay at exit (inches) 28.8 in 45 Does water flow out of the forebay in a non -erosive manner? Yes 46 Width of the ve etated shelf (feet) 6 It 47 Slope of vegetated shelf H: 6:1 48 Does the orifice drawdown from below the top surface of the permanentpool? Yes 49 Does the pond minimize impacts to the receiving channel from the 1 r 24-hr storm? Yes 50 Are fountains proposed? (If Y, please provide documentation that MDC 9 is met. No 51 Is a trash rack or other device provided to protect the outlet system? Yes 52 Are the dam and embankment planted in non -clumping turf grass? Yes 53 Species of turf that will be used on the dam and embankment Hybrid Bermuda 54 Hasa lanting plan been rovided for the ve etated shelf? Yes ADDITIONAL INFORMATION 55 Please use this space to provide any additional information about the wet pond(s); Wet Pond 1 8:40 AM 8/23/2021