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Home My WebLink AboutSW6221102_Supplement-EZ Form_20230228SUPPLEMENT-EZ COVER PAGE FORMS LOADED PROJECT INFORMATION 1 Project Name Utility Improvements to Serve Ashley Heights 2 Project Area ac 91.286 _ 3 Coastal Wetland Area ac - 4 Surface Water Area ac - 5 Is this project High or Low Density? High 6 jDoes this project use an off -site SCM? No COMPLIANCE WITH 02H .1003(4) 7 Width of vegetated setbacks provided feet N/A 8 Will the vegetated setback remain vegetated? N/A 9 If BUA is pro2osed 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: 11 Infiltration System 1 0 12 Bioretention Cell 13 Wet Pond 2 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 Treatment Swale 0 22 Dry Pond 0 23 StormFilter 0 24 Silva Cell 0 25 Bayfilter 0 26 Filterra 0 FORMS LOADED DESIGNER CERTIFICATION 27 28 Name and Title: _ Organization: Street address: Carlo Pardo, PE Bowman North Carolina, Ltd. 29 4006 Barrett Drive, Suite 104 30 City, State, Zip: Raleigh, NC 27609 31 Phone number(s): Email: 919-553-6570 32 cpardo@bowman.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. ,�1111flllllil"t.11 o s s ' a,y •. 4 SEAL 051571 - 1�+0 I E 1�a_ Signature of Designer Date DRAINAGE AREAS 1 Is this a hi h 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 Is all/part of this project subject to previous rule versions? No FORMS LOADED AREA INFORMATION Entire Site 1 2 3 4 T e of SCM - Infiltration Basin Wet Pond Wet Pond 5 Total draina a area s ft 3976419 sf 519352 sf 590407 sf 2729441 sf 6 Onsite draina a areas ft 519052 sf 590407 sf 2619583 sf 7 Offsite draina a area s ft 300 sf 109858 sf 8 Total BUA in project (sq ft 768212 sf 102967 sf 133829 sf 641574 sf 9permitting) New BUA on subdivided lots (subject to s ft 528000 sf 68000 sf 92000 sf 368000 sf 10permitting) New BUA not on subdivided lots (subject to s 240212 sf 34667 sf 41829 sf 163716 sf 11 10ffsite BUA (sq ft 300 sf 109858 sf 12 Breakdown of new BUA not on subdivided lots: Parking (sq ft Sidewalk (sq ft 34418 sf 4896 sf 5822 sf 23700 sf Roof (sq ft Roadway s ft 205794 sf 29771 sf 36007 sf 140016 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 subdivided 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 19.32% 19.84% 22.67% 23.51% 19 Design storm inches 1.0 in 1.0 in 1.0 in 20 Design volume of SCM cu ft 10232 cf 43908 cf 163392 cf 21 Calculation method for design volume Simple Method Simple Method Simple Method DDITIONAL INFORMATION Please use this space to provide any additional information about the r22drainage area(s): INFILTRATION SYSTEM 1 Drainage area number 2 1 Minimum required treatment volume (cu ft) ERAL 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 or enter "Vertical' for trenches)? 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- ear storm)? Yes 8 Is there an overflow or bypass for inflow volume in excess of the design volume? Yes 9 lWhat is the method for dewatering the SCM for maintenance? Pump (preferred) 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 device specific MDC? Yes 17 Was the SCM designed by an NC licensedprofessional? Yes 18 1 Proposed slope of the subgrade surface (%) 0% 19 jAre terraces or baffles provided? No 20 1Tvpe of pretreatment: Forebay Data 21 Was the soil investigated in the footprint and at the elevation of the infiltrations stem? Yes 22 SHWT elevation (fmsl) 434.00 23 Depth to SHWT per soils report (in) 120.00 24 Ground elevation at boring in soils report (fmsl) 444.00 25 Is a detailed hydrogeologic study attached if the separation is between 1 and 2 feet? N/A 26 ISoil infiltration rate (in/hr) 4.25 27 1 Factor of safety (FS) (2 is recommended): 2.00 Elevations 29 113ottom elevation (fmsl) 440 ft 30 IStorage elevation (fmsl) 441.2 ft 31 1 Bypass elevation (fmsl) 445.5 ft Basins 32 1 Bottom surface area(ft) 7755 ft 33 Istorage elevation surface area(ft) 9300. ft For Trenches Only 34 Length (ft) 35 Width (ft) 36 Perforated pipe diameter, if applicable (inches) 37 Number of laterals 38 Total length of perforated piping 39 Stone type, if applicable 40 Stone porosity (%) 41 Is stone free of fines? 42 Is the stone wrapped in geotextile fabric? 43 Has at least one inspection port been provided? Volumes/Drawdown 44 IDesign volume of SCM (cu ft) 10232 cf 45 ITime to draw down (hours) 7.5 hrs I 46 Please use this space to provide any additional information about I the infiltration system(s): 26-The infiltration rate was intentially lowered to half of the 8.25 in/hr to unt for clogginq of the soils that will happen over time. Infiltration 1 10:32 AM 2/27/2023 WET POND 1 11 Drainage area number 2 3 21 Minimum required treatment volume (cu ft) 12497 cf 59491 cf NERAL 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 5 What are the side slopes of the SCM (H:V)? 3:1 3:1 6 Does the SCM have retaining walls, gabion walls or other engineered side slopes? No No 7 Are the inlets, outlets, and receiving stream protected from erosion 10- ear storm)? Yes Yes 8 Is there an overflow or bypass for inflow volume in excess of the design volume? Yes Yes 9 What is the method for dewatering the SCM for maintenance? Pump (preferred) 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 General MDC (10)? N/A N/A 14 Is there an O&M Agreement that complies with General MDC (11)? Yes Yes 151 Is there an O&M Plan that complies with General MDC (12)? Yes Yes 161 Does the SCM follow the device specific MDC? Yes Yes 17 Was the SCM designed b an NC licensedprofessional? Yes Yes WET POND MDC FROM 02H .1053 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 removal) (fmsl 405.00 409.00 21 Elevation of the main pool bottom (top of sediment removal) (fmsl) 406.00 410.00 22 Elevation of the bottom of the vegetated shelf (fmsl) 410.50 414.50 23 Elevation of the permanent pool (fmsl) 411.00 415.00 24 Elevation of the top of the vegetated shelf (fmsl) 411.50 415.50 25 Elevation of the temporary pool (fmsl) 412.40 417.10 26 Surface area of the main permanent pool (square feet) 21945 56230 27 Volume of the main permanent pool (cubic feet) 90710 cf 245796 cf 28 Average depth of the main pool (feet) 4.46 ft 4.61 ft 29 Average depth equation used Equation 3 Equation 3 301 If using equation 3, main pool perimeter (feet) 577.0 ft 1051.0 ft 31 If using equation 3, width of submerged veg. shelf (feet) 3.0 ft 3.0 ft 32 Volume of the forebay (cubic feet) 14673 cf 43558 cf 33 Is this 15-20% of the volume in the main pool? Yes Yes 34 Clean -out depth for forebay (inches) 36 in 48 in 35 Design volume of SCM (cu ft) 43908 cf 163392 cf 36 Is the outlet an orifice or a weir? Orifice Orifice 371 If orifice, orifice diameter (inches) 2.50 in 4.50 in 38 If weir, weir height (inches) 39 If weir, weir length (inches) 40 Drawdown time for the temporary pool (days) 3.67 3.78 41 Are the inlet(s) and outlet located in a manner that avoids short- circuiting? Yes Yes 42 Are berms or baffles provided to improve the flow path? Yes Yes 431 Depth of forebay at entrance (inches) 48 in 60 in 44 Depth of forebay at exit (inches) 36 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) 6 ft 6 ft 47 Slope of vegetated shelf (H:V) 6:1 6:1 48 Does the orifice drawdown from below the top surface of the permanentpool? Yes Yes 49 Does the pond minimize impacts to the receiving channel from the 1- r, 24-hr storm? Yes Yes 50 Are fountains proposed? (If Y, please provide documentation that MDC 9 is met. No 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 Hasa planting plan been provided for the vegetated shelf? Yes Yes ADDITIONAL INFORMATION 55 Please use this space to provide any additional information about the wet pond(s): Wet Pond 1 10:32 AM 2/27/2023