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Home My WebLink AboutSW6230502_Supplement-EZ Form_20230605SUPPLEMENT-EZ COVER PAGE PROJECT INFORMATION 1 Project Name Ducks Landing 2 Project Area (ac) 107.229 3 Coastal Wetland Area (ac) 4 Surface Water Area (ac) _ ..... m ®.. _.... _.. 2,494 5 Is this project High or Low Density? Hi h 6 Does this project use an off -site SCM? No NUMBER AND TYPE OF SCMs^ ... 1..�.. stem Infiltration S) -- .----- .. _.............. .... . 3 12 - Bioretention Cell ...... ----- ®- 0 _._. _._ ,. ............. 13 Wet Pond 2 1. 14 Stormwater Wetland ..... - - ------ ----- _-------- 0 ..� .... . ................ _._... 15 Perm --------- ®a. Sand Filter , ®. ® _, --- p 17 Rainwater Harvesting (RWH) ..,,..,.,,,, ... ..... 0 ...................... ...... .......................... .......... .......... ....... ......�.�. 18 Green Roof p 19 Level Spreader Filter Strip (LS FS) .... 0 20 Disconnected Impervious -- .. P , m s Surface ( - m e.... 21 Treatment Swale _, .... ....� .................. _................. _ ,... 0 22 D P Dry,Pond me� 0 ....... .... _��.� .�. ...._ ..........�. .. ..-- 23 StormFilter ..... ......... 0 24 ... Silva Cell .. --- ...... . - _ M.,,,,, , ®.. .�.� ..�._..._� a.. ........... ...... 0 2bBa lter ,., ...�e,.... 26 Filterra _. ..._.. _-___-- � ----_..._.0..,,---------- ,-_ 0 FORMS LOADED 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,. 0�))VII IICA fiiPtIPiA/f .0 SS10 SEAL '51 571 sr^" a° a� Signature of Designer ti,73&X� ____ Date DRAINAGE AREAS 1 Is this a high density project? Yes ............................................................................................................................................................................................................................................................................................................................................................................................................ 2 If so, number of drains a areas/SCMs 5 3 ............................................................................................................................................................................................................................................................................................................................................................................................................ Does this project have low density areas? No 4 If so, number of low densit drains a areas .......................................................................................................................................................................................................................................................................................... 0 Is all/part of this project subject to previous rule 5 versions? No IFORIMS ILOADIE::.D DRAINAGE AREA INFORMATION Entire Site 1 2 4 Type of SCM - Infiltration Basin Infiltration Basin 5 Total drainage area (sq ft 4670880 sf 564434 599880 6 Onsite drainage area (sq ft) 4670880 sf 564434 599880 7 Offsite drains a area s ft ............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 8 Total BUA in ro ect s ft 665787 sf ..........1................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. 125494 sf 128952 sf New BUA on subdivided lots (subject to permitting) 9 s ft 496000 sf 76000 sf 104000 sf New BUA not on subdivided lots (subject to 10 ermittin s 169787 sf ............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 49494 sf 24952 sf 11 Offsite BUAs ft ...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 12 Breakdown of new BUA not on subdivided lots: - Parkin s ft - Sidewalks ft ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... - Roofs ft - Roadwa (sq ft 169787 sf 49494 sf 24952 sf - Futures ft - Other, please specify in the comment box below s ft .................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... New infiltrating permeable pavement on subdivided 13 lots s ft New infiltrating permeable pavement not on 14 subdivided lots s ft Existing BUA that will remain (not subject to 15 ermittin s ft .......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 16 Existin BUA that is already ermitted s ft 17 Existin BUA that will be removed s ft 18 Percent BUA 14.25% 22.2% 21.5% 19 Desi n storm inches 1.0 in 1.0 in 20 Design volume of SCM cu ft 65913 cf 76300 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 9 (s:) There is 108,653 sf (2.494 ac) of surface water area. DRAINAGE AREAS 1 Is this a high density project? Yes ............................................................................................................................................................................................................................................................................................................................................................................................................ 2 If so, number of drains a areas/SCMs 5 3 ............................................................................................................................................................................................................................................................................................................................................................................................................ Does this project have low density areas? No 4 If so, number of low densit drains a areas .......................................................................................................................................................................................................................................................................................... 0 Is all/part of this project subject to previous rule 5 versions? No IFORIMS ILOADIE::.D DRAINAGE AREA INFORMATION Entire Site 3 4 4 Type of SCM - Infiltration Basin Wet Pond 5 Total drainage area (sq ft 4670880 sf 261143 917130 6 Onsite drainage area (sq ft) 4670880 sf 261143 917130 7 Offsite drains a area s ft ............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 8 Total BUA in ro ect s ft 665787 sf ..........1................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. 38138 sf 232735 sf New BUA on subdivided lots (subject to permitting) 9 s ft 496000 sf 28000 sf 180000 sf New BUA not on subdivided lots (subject to 10 ermittin s 169787 sf ............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 10138 sf 52735 sf 11 Offsite BUAs ft ...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 12 Breakdown of new BUA not on subdivided lots: - Parkin s ft - Sidewalks ft ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... - Roofs ft - Roadwa (sq ft 169787 sf 10138 sf 52735 sf - Futures ft - Other, please specify in the comment box below s ft .................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... New infiltrating permeable pavement on subdivided 13 lots s ft New infiltrating permeable pavement not on 14 subdivided lots s ft Existing BUA that will remain (not subject to 15 ermittin s ft .......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 16 Existin BUA that is already ermitted s ft 17 Existin BUA that will be removed s ft 18 Percent BUA 14.25% 14.6% 25.4% 19 Desi n storm inches 1.0 in 1.0 in 20 Design volume of SCM cu ft 30070 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 9 (s:) There is 108,653 sf (2.494 ac) of surface water area. DRAINAGE AREAS 1 Is this a high density project? Yes ............................................................................................................................................................................................................................................................................................................................................................................................................ 2 If so, number of drains a areas/SCMs 5 3 ............................................................................................................................................................................................................................................................................................................................................................................................................ Does this project have low density areas? No 4 If so, number of low densit drains a areas .......................................................................................................................................................................................................................................................................................... 0 Is all/part of this project subject to previous rule 5 versions? No IFORIMS ILOADIE::.D �Dli �� 1�1��N�AG�E��AREA��N�FORAT��ON��Entire Site 5�� 4 Type of SCM - Wet Pond 5 Total drainage area (sq ft 4670880 sf 701836 6 Onsite drainage area (sq ft) 4670880 sf 701836 7 Offsite drains a area s ft ........................................................................................................................................................................................................................................................................................................................................................................................................................................... 8 Total BUA in ro ect s ft 665787 sf ..........1............................................................................................................................................................................................................................................................................................................................................................................. 140468 sf New BUA on subdivided lots (subject to permitting) 9 s ft 496000 sf 108000 sf New BUA not on subdivided lots (subject to 10 ermittin s 169787 sf ........................................................................................................................................................................................................................................................................................................................................................................................................................................................ 32468 sf 11 Offsite BUAs ft .................................................................................................................................................................................................................................................................................................................................................................................................. 12 Breakdown of new BUA not on subdivided lots: - Parkin s ft - Sidewalks ft ............................................................................................................................................................................................................................................................................................................................................................................................... - Roofs ft - Roadwa (sq ft 169787 sf 32468 sf - Futures ft - Other, please specify in the comment box below s ft ................................................................................................................................................................................................................................................................................................................................................................................................................................ New infiltrating permeable pavement on subdivided 13 lots s ft New infiltrating permeable pavement not on 14 subdivided lots s ft Existing BUA that will remain (not subject to 15 ermittin s ft ...................................................................................................................................................................................................................................................................................................................................................................................................................................................... 16 Existin BUA that is already ermitted s ft 17 Existin BUA that will be removed s ft 18 Percent BUA 14.25% 20.0% 19 Desi n 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 9 (s:) There is 108,653 sf (2.494 ac) of surface water area. INFILTRATION SYSTEM number area nu��... 2 ..,rainage Minimum re mired treatment volume cu ft 11764 cf ...... ...... ��., ...... ....� .. 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- ear 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 (prefer 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 lWas the SCM desi ned b an NC licensed rofessionaI ? 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 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 infiltrations stem? 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 iltion rate (in/hr) 5.00 4.0027 L%��tor 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 �L L33 [Bofa a elevation surface area ftZ 16815. ft 19080. ft 12075. ft For Trenches Only Infiltration 1 3:02 PM 5/16/2023 WET POND 1 Drainage area number 4 5 2 Minimum re uired treatment volume cu ft inimu required � ( ) 21277 cf 134 59 cf GENERAL 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 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 (prefer 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 18 Sizing method used SA/DA SA/DA 19 Has a stage/storage table been provided in the calculations? Yes Yes Elevation of the excavated main pool depth (bottom of sediment 20 179.00 204.00 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) 36 in 36 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) ....If 39 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(?) 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 ded for the ve etated shelf 54 ,Has a �lantin��lan ,been rove, c� Yes .. .. Yes .. .. �ITIONAL INFORMATION Please use this s ace to rovide an additional informationabout 55 p p Y the wet oond(s): Wet Pond 1 3:02 PM 5/16/2023