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Home My WebLink AboutSWA000022__02 Supplemental EZ Form - Signed_20201001SUPPLEMENT-EZ COVER PAGE f URMS LOA00 PROJECT INFORMATION 1 Project Name Courtyards at Emerald Lake 2 Project Area ac 33.54 3 Coastal Wetland Area ac 0 4 Surface Water Area ac 0.5 5 1 Is this project High or Low Density? High 6 1 Does this project use an off -site SCM? No COMPLIANCE WITH 02H.1003(4) 7 Width of vegetated setbacks provided feet 100 8 Will the vegetated setback remain ve etated? Yes 9 Is BUA other that as listed in .1 0034 c-d out of the setback? Yes 10 Is streambank stabilization proposed on this project? No NUMBER AND TYPE OF SCMs: 11 Infiltration System Bioretention Cell 0 12 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-F$ 0 20 Disconnected Impervious Surface (DIS) 0 21 Treatment Swale 0 22 1 Dry Pond 0 23 StormFilter 0 24 Silva Cell 0 25 Bay alter 0 26 Filterra 0 FORMS LOADED DESIGNER CERTIFICATION 27 Name and Title: Brian Rossi, PE/ Project Mana er 28 Organization: EMH&T 29 Street address: 301 McCullough Dr 30 City, State, Zip: Phone numbers : Email: Charlotte NC 28262 31 704-548-0333 32 brossi@emht.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. ��►111f I11) f f ry►,CA tss SEAL 045526 ref J•/r ��1I I I t I l t�O''``\, 5 nature of Designer 0q Z1 I 2zZo Date DRAINAGE AREAS 1 Is this a hi h density project? Yes 2 If so, number of drainage areas/SCMs 2 Is all/part of this project subject to previous rule 3 versions? No FORMS LOADED DRAINAGE AREA INFORMATION Entire Site 1 2 4 Type of SCM Wet Ponds East Pond 1&2 West Pond 3 5 Total BUA in project s ft 486769 sf 373357 sf 91119 sf 6 New BUA on subdivided lots (subject to permitting) (sq ft 358390 sf 266764 sf 74707 sf 7permitting) New BUA outside of subdivided lots (subject to s 128379 sf 106594 sf 16411 sf 8 Offsite - total area (sq ft Offsite BUA (sq ft Breakdown of new BUA outside subdivided lots: Parking (sq ft Sidewalk (sq ft sf 13939 sf 9 - sf sf 10 5801 sf 5801 sf sf 20067 sf 6302 sf 15341 sf 4908 sf 2694 sf sf Roof (sq ft Roadway s ft Future (sq ft) Other, please specify in the comment box below (sq ft 96210 sf 80545 sf 13717 sf sf sf sf sf sf sf 11 New infiltrating permeable pavement on subdivided lots (sq ft sf sf sf 12 New infiltrating permeable pavement outside of subdivided lots (sq ft sf sf sf 13permitting) Exisitng BUA that will remain (not subject to s ft sf sf sf 14 Existing BUA that is already permitted (sq ft sf sf sf 15 Existing BUA that will be removed (sq ft sf sf sf 16 Percent BUA 34% 45% 50% 17 Design storm inches (1-yr post) - (1yr re) (1-yr post) - (1yr pre 18 Design volume of SCM cu ft 50661 cf 12408 Gf 19 Calculation method for design volume Discrete NRCS curve Number Method I Discrete NRCS curve Number Method ADDITIONAL INFORMATION 20 ldrainage Please use this space to provide any additional information about the areas : WET POND 1 Drainage area number 1&2 3 2 Design volume of SCM (cu ft) 50661 cf 12408 cf f; Rai Mnr rAnm n7u Inca ice' 3 Is the SCM sized to treat the SW from all surfaces at build -out? Yes Fes 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-year 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? Drawdown Orifice Drawdown Orifice 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 No Yes 13 If the SCM is on a single family lot, does (will?) the plat comply with General MDC (10)? Is there an O&M Agreement that complies with General MDC (11)? Is there an O&M Plan that complies with General MDC (12)? No 14 15 Yes Yes Yes Yes Yes Yes 16 Does the SCM follow the device specific MDC? T7 Was the SCM designed by an NC licensed professlanai? Yes Yes WCT anon unr. FPnM 117114 Ines 18 19 Method used Has a stage/storage table been provided in the calculations? SA/DA SA/DA Yes Yes 20 Elevation of the excavated main pool depth (bottom of sediment removal) (fmsl) 626.48 634.00 21 Elevation of the main pool bottom -(top of sediment removal) (fmsl) 627.48 635.00 22 Elevation of the bottom of the vegetated shelf (fmsl 634.00 638.80 23 Elevation of the permanent pool (fmsl) 634.50 639.28 24 Elevation of the top of the vegetated shelf (fmsl) 635.00 639.80 25 Elevation of the temporary pool (fmsQ 637.51 640.39 26 Surface area of the main permanent pool (square feet) 15636:1 6350:1 27 Volume of the main permanent pool (cubic feet) 60943 cf 19040 cf 28 Average depth of the main pool (feet) 3.90 ft 3.00 ft 29 Average depth equation used Equation 2 Equation 2 30 If using equation 3, main pool perimeter (feet) 31 If using equation 3, width of submerged veg. shelf (feet) 32 Volume of the forebay (cubic feet) 21534 cf 3456 cf 33 Is this 15-20% of the volume in the main pool? No No 34 Clean -out depth for forebay (inches) 84 in 39 in 35 Design volume of SCM (cu ft) 50661 cf 12408 cf 36 Is the outlet an orifice or a weir? Orifice Orifice 37 If orifice, orifice diameter (inches) 2 in 1 in 38 If weir, weir height (inches) 39 If weir, weir length (inches) 40 Drawdown time for the temporary pool (days) 4.19 4.84 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? No No 43 Depth of forebay at entrance (inches) 73 in 70 in 44 Depth of forebay at exit (inches) 78 in 76 in 45 Does water flow out of the forebay in a non -erosive manner? Yes Yes 46 Width of the vegetated shelf (feet) 8 ft loft 47 Slope of vegetated shelf (H:V) 8:1 10:1 48 Does the orifice drawdown from below the top surface of the permanent pool? Yes Yes 49 Does the pond minimize impacts to the receiving channel from the 1- yr, 24-hr storm? Yes Yes 50 Are fountains proposed? (If Y, please provide documentation that MDC(9) is met.) Is a trash rack or other device provided to protect the outlet system? Yes Yes 51 No No 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 Bermuda Red Bermuda Red 54 Has a planting plan been provided or the vegetated shelf? yft Yes ADDITIONAL INFORMATION Please use this space to provide any additional information aboul the w 55 et pana(a): 33, The basins were designed and approved in 2014, when the 15-20% was not a requirement. The former DEQ manual requested "Approximately 20%" volume in the forebays. Both basins provide over 20% of the below normal pool volume providing extra settling opportunities for both basins. Wet Pond 3 3:12 PM 7/10/2020