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Home My WebLink AboutSW6230502_Supplement-EZ Form_20231004 SUPPLEMENT-EZ COVER PAGE FORMS LOADED PROJECT INFORMATION 1 Project Name _ Ducks Landing 2 Project Area(ac) _ 109.668 3 Coastal Wetland Area(ac) - 4 Surface Water Area(ac) 2.494 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) 30 8 Will the vegetated setback remain vegetated? Yes 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 1i NUMBER AND TYPE OF SCMs: 11 Infiltration System 3 12 Bioretention Cell _ 0 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 Name and Title: Carlo Pardo,PE 28 Organization: Bowman North Carolina,Ltd. 29 Street address: _ 4006 Barrett Drive,Suite 104 30 City,State,Zip: Raleigh,NC 27609 31 Phone number(s): 919-553-6570 32 Email: 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. Designer �� EESSIp�;9'yq l '-. -.-- C9- 6.1"--:7;7-," SEAL _ Signature of Designer 051571 73 ii C 0 E P \\\• ` >� �7iii111iiiuQkh° Date DRAINAGE AREAS 1 I Is this a high density project? Yes _ 2 If so, number of drainage areas/SCMs 5 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 3 4 • 4 Type of SCM - Infiltration Basin Wet Pond 5 Total drainage area (sq ft) 4777138 sf 261143 917130 6 Onsite drainage area (sq ft) 4777138 sf 261143 917130 7 Offsite drainage area (sq ft) 8 Total BUA in project (sq ft) 665787 sf 38138 sf 232735 sf New BUA on subdivided lots (subject to permitting) 9 (sq ft) 496000 sf i 28000 sf 180000 sf New BUA not on subdivided lots (subject to 10 permitting) (sf) 169787 sf 10138 sf 52735 sf 11 Offsite BUA (sq ft) 12 Breakdown of new BUA not on subdivided lots: - Parking (sq ft) - Sidewalk (sq ft) - Roof (sq ft) - Roadway (sq ft) 169787 sf 10138 sf 52735 sf - Future (sq ft) - Other, please specify in the comment box below (sq ft) New infiltrating permeable pavement on subdivided 13 lots (sq ft) New infiltrating permeable pavement not on 14 subdivided lots (sq ft) Existing BUA that will remain (not subject to 15 permitting) (sq ft) 16 Existing BUA that is already permitted (sq ft) 17 Existing BUA that will be removed (sq ft) 18 Percent BUA 13.94% 14.6% 25.4% 19 Design storm (inches) _ 1.0 in 1.0 in 20 Design volume of SCM (cu ft) _ 30515 cf 23500 cf 21 Calculation method for design volume Simple Method Simple Method ADDITIONAL INFORMATION Please use this space to provide any additional information about the 22 drainage area(s): _ There is 108,653 sf (2.494 ac) of surface water area. DRAINAGE AREAS 1 I Is this a high density project? Yes _ 2 If so, number of drainage areas/SCMs 5 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 5 • 4 Type of SCM - Wet Pond 5 Total drainage area (sq ft) 4777138 sf 701836 6 Onsite drainage area (sq ft) 4777138 sf 701836 7 Offsite drainage area (sq ft) 8 Total BUA in project (sq ft) 665787 sf 140468 sf New BUA on subdivided lots (subject to permitting) 9 (sq ft) 496000 sf i 108000 sf New BUA not on subdivided lots (subject to 10 permitting) (sf) 169787 sf 32468 sf 11 Offsite BUA (sq ft) 12 Breakdown of new BUA not on subdivided lots: - Parking (sq ft) - Sidewalk (sq ft) - Roof (sq ft) - Roadway (sq ft) 169787 sf 32468 sf - Future (sq ft) - Other, please specify in the comment box below (sq ft) New infiltrating permeable pavement on subdivided 13 lots (sq ft) New infiltrating permeable pavement not on 14 subdivided lots (sq ft) Existing BUA that will remain (not subject to 15 permitting) (sq ft) 16 Existing BUA that is already permitted (sq ft) 17 Existing BUA that will be removed (sq ft) 18 Percent BUA 13.94% 20.0% 19 Design storm (inches) _ 1.0 in 20 Design volume of SCM (cu ft) _ 15571 cf 21 Calculation method for design volume Simple Method ADDITIONAL INFORMATION Please use this space to provide any additional information about the 22 drainage area(s): _ There is 108,653 sf (2.494 ac) of surface water area. INFILTRATION SYSTEM 1 Drainage area number 1 2 3 2 Minimum required treatment volume(cu ft) 11764 cf I 12171 cf 3948 cf GENERAL MDC FROM 02H.1050 3 Is the SCM sized to treat the SW from all surfaces at build-out? Yes Yes Yes 4 Is the SCM located away from contaminated soils? Yes Yes Yes 5 What are the side slopes of the SCM(H:V or enter"Vertical"for trenches)? 3:1 3:1 3:1 6 Does the SCM have retaining walls,gabion walls or other engineered side slopes? No No No 7 Are the inlets,outlets,and receiving stream protected from erosion (10-year storm)? Yes _ Yes _ Yes 8 Is there an overflow or bypass for inflow volume in excess of the design volume? Yes Yes Yes 9 What is the method for dewatering the SCM for maintenance? Pump(preferred) Pump(preferred) Pump(preferred) 10 If applicable,will the SCM be cleaned out after construction? Yes Yes Yes 11 Does the maintenance access comply with General MDC(8)? Yes _ Yes Yes 12 Does the drainage easement comply with General MDC(9)? Yes 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 N/A 14 Is there an O&M Agreement that complies with General MDC(11)? Yes Yes Yes 15 Is there an O&M Plan that complies with General MDC(12)? Yes Yes Yes 16 Does the SCM follow the device specific MDC? Yes Yes Yes 17 Was the SCM designed by an NC licensed professional? Yes Yes Yes INFILTRATION SYSTEM MDC FROM 02H.1051 18 Proposed slope of the subgrade surface(%) 0% 0% 0% 19 Are terraces or baffles provided? No T-- No No 20 Type of pretreatment: Forebay Forebay Forebay Soils Data 21 Was the soil investigated in the footprint and at the elevation of the infiltration system? Yes Yes Yes 22 SHWT elevation(fmsl) 196.00 184.00 180.00 23 Depth to SHWT per soils report(in) 144 in _ 144 in 144 in 24 Ground elevation at boring in soils report(fmsl) 208.00 196.00 192.00 25 Is a detailed hydrogeologic study attached if the separation is between 1 and 2 feet? N/A Yes Yes 26 Soil infiltration rate(in/hr) 5.00 4.00 4.00 27 Factor of safety(FS) (2 is recommended): 2.00 2.00 2.00 Elevations 29 Bottom elevation(fmsl) 208 ft 196 ft 192 ft 30 Storage elevation(fmsl) 213.ft 201.ft 195.ft 31 Bypass elevation(fmsl) 213 ft 201 ft 195 ft For Basins Only 32 Bottom surface area(ft2) 9970 ft I 11980 ft 8345 ft 1 33 Storage elevation surface area(ft2) 16815.ft 19080.ft 12075.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 Design volume of SCM(cu ft) 66388 cf 77080 cf 30515 cf 45 Time to draw down hours 19.0 hrs 24.2 hrs 15.2 hrs ADDITIONAL INFORMATION 46 Please use this space to provide any additional information about the infiltration system(s): Line 26-The soils report found the infiltration rate of the soil for DA 1 to be 10.0'/hr. A more conservative value of 5.0'/hr was used in the calculations,to account for clogging of the soils that will happen over time.The soils report found the infiltration rate of the soil for DAs 2&3 to be 8.0'/hr.A more conservative value of 4.0'/hr was used in the calculations,to account for clogging of the soils that will happen over time. Infiltration 1 1:19 PM 7/5/2023 WET POND 1 Drainage area number 4 5 I 2 Minimum required treatment volume(Cu ft) 21277 cf 13459 cf 'GENERAL MDC FROM 02H.1050 31 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 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? 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 If the SCM is on a single family lot,does(will?)the plat comply with 13 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 designed by an NC licensed professional? 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 179.00 204.00 removal)(fmsl) 21 Elevation of the main pool bottom(top of sediment removal)(fmsl) 180.00 205.00 22 Elevation of the bottom of the vegetated shelf(fmsl) 184.50 209.50 23 Elevation of the permanent pool(fmsl) 185.00 210.00 24 Elevation of the top of the vegetated shelf(fmsl) 185.50 210.50 25 Elevation of the temporary pool(fmsl) 185.70 210.50 26 Surface area of the main permanent pool(square feet) 24370 22680 27 Volume of the main permanent pool(cubic feet) 101055 cf 93535 cf 28 Average depth of the main pool(feet) 4.47 ft 4.45 ft 29 Average depth equation used Equation 3 Equation 3 30 If using equation 3,main pool perimeter(feet) 630.0 ft 602.0 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) 18360 cf 17178 cf 33 Is this 15-20%of the volume in the main pool? Yes Yes 34 Clean-out depth for forebay(inches) 12 in 12 in 35 Design volume of SCM(cu ft) 23500 cf 15571 cf 36 Is the outlet an orifice or a weir? Orifice Orifice 37 If orifice,orifice diameter(inches) 2.00 in 2.00 in 38 If weir,weir height(inches) 39 If weir,weir length(inches) 40 Drawdown time for the temporary pool(days) 3.81 2.66 41 Are the inlet(s)and outlet located in a manner that avoids short- Yes Yes circuiting? 42 Are berms or baffles provided to improve the flow path? Yes Yes 43 Depth of forebay at entrance(inches) 48 in 48 in 44 Depth of forebay at exit(inches) 42 in 42 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 Yes Yes permanent pool? 49 Does the pond minimize impacts to the receiving channel from the 1- Yes Yes yr,24-hr storm? 50 Are fountains proposed?(If Y,please provide documentation that No No MDC(9)is met.) 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 ADDITIONAL INFORMATION Please use this space to provide any additional information about 55 the wet pond(s): Wet Pond 1 2:38 PM 7/5/2023