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Home My WebLink About20181259 Ver 2_Docs_3 - Supplemental EZ_20200925SUPPLEMENT-EZ COVER PAGE FORMS LOADED PROJECT INFORMATION 1 I Project Name Rivercross 73.89 0 2 Project Area (ac) 3 Coastal Wetland Area (ac) 4 Surface Water Area (ac) 1.52 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) 50 8 Will the vegetated setback remain vegetated? Yes 9 Is BUA other that as listed in .1003(4)(c-d) out of the setback? Yes 10 Is streambank stabilization proposed on this project? No NUMBER AND TYPE OF SCMs: 11 Infiltration System 0 12 Bioretention Cell 0 13 Wet Pond 0 14 Stormwater Wetland 0 15 Permeable Pavement 0 16 Sand Filter 4 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 1 Dry Pond 4 23 StormFilter 0 24 Silva Cell 0 25 Bayfilter 5 26 Filterra 0 FORMS LOADED DESIGNER CERTIFICATION 27 Name and Title: Brian Smith, PE 28 Organization: Urban Design Partners, LLC 29 Street address: 1318 Central Avenue, Suite E6 30 City, State, Zip: Charlotte, NC 28205 31 Phone number(s): 704-334-3303 32 Email: brian@urbandesignpartners.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. CA 06FEssio SEAL 027890 - -- SiS%WrelofDesigner 08.03.2020 Date DRAINAGE AREAS 1 Is this a high density project? Yes 2 If so, number of drainage areas/SCMs 9 3 Is all/part of this project subject to previous rule versions? No FORMS LOADED DRAINAGE AREA INFORMATION Entire Site 1 2 3 4 5 6 7 8 9 4 Type of SCM Sand Filter/Dry Pond Sand Filter/Dry Pond Sand Filter/Dry Pond Sand Filter/Dry Pond Underground Detention/Bay Filter Underground Detention/Bay Filter Underground Detention/Bay Filter Underground Detention/Bay Filter Underground Detention/Bay Filter 5 Total BUA in protect (sq ft) 1258894 sf 31675 sf 81390 sf 83520 sf 171315 sf 46855 sf 169835 sf 229430 sf 162141 sf 282733 sf 6 New BUA on subdivided lots (subject to permitting) (sq ft) 641721 sf 15130 sf 36415 sf 35055 sf 99280 sf 32530 sf 72650 sf 117140 sf 83866 sf 149655 sf 7 New BUA outside of subdivided lots (subject to permitting) (sf) 617173 sf 16545 sf 44975 sf 48465 sf 72035 sf 14325 sf 97185 sf 112290 sf 78275 sf 133078 sf 8 Offsite - total area (sq ft) 9 Offsite BUA (sq ft) 10 Breakdown of new BUA outside subdivided lots: Parking (sq ft) 3000 sf 3000 sf Sidewalk (sq ft) 255758 sf 2035 sf 20075 sf 19850 sf 33680 sf 8350 sf 42390 sf 42650 sf 30340 sf 56388 sf Roof (sq ft) 7000 sf 7000 sf Roadway (sq ft) 346415 sf 14510 sf 24900 sf 28615 sf 38355 sf 5975 sf 54795 sf 54640 sf 47935 sf 76690 sf Future (sq ft) Other, please specify in the comment box below (sq ft) 5000 sf 5000 sf 11 New infiltrating permeable pavement on subdivided lots (sq ft) 12 New infiltrating permeable pavement outside of subdivided lots (sq ft) 13 Exisitng BUA that will remain (not subject to permitting) (sq ft) 14 Existing BUA that is already permitted (sq ft) 15 Existing BUA that will be removed (sq ft) 16 Percent BUA 53 % 13 % 67 % 61 % 50 % 56 % 68 % 58 % 56 % 58 17 Design storm (inches) 1 in 1 in 1 in 1 in 1 in 1 in 1 in 1 in 1 in 1 in 18 Design volume of SCM (cu ft) 2565 cf 4955 cf 5124 cf 10709 cf 2898 cf 10332 cf 14136 cf 10026 cf 17428 cf 19 Calculation method for design volume Simple Simple Simple Simple Simple Simple Simple Simple Simple Simple ADDITIONAL INFORMATION 20 Please use this space to provide any additional information about the drainage area(s): Parking, roof & other impervious in basin 7 accounts for amenity area SAND FILTER 18 SHWT elevation (fmsl) TBD TBD TBD TBD 19 Type of sand filter (open or closed) Open Open Open Open 20 If closed, will the filter will be pre -cast or pour -in -place? 21 If closed, top of grate elevation (fmsl) 22 Is this sand filter designed to attenuate peak flows? Yes Yes Yes Yes Sediment Chamber 23 Volume that can be retained in the sediment chamber (cubic feet) 3327 cf 4988 cf 5156 cf 12337 cf 24 Will there be a permanent pool in the sediment chamber? No No No No 25 Bottom of the sediment chamber (fmsl) 761.00 753.00 746.00 748.00 26 Area of the sediment chamber (square feet) 1700 sf 3119 sf 3305 sf 5296 sf 27 Physical depth of the sediment chamber (inches) 36 in 24 in 24 in 36 in 28 Ponding depth in the sediment chamber, above any permanent pool (inches) 26 in 1 24 in 1 27 in 1 27 in 29 1 Elevation of top of weir between chambers (fmsl) 764 1 755 1 748 1 751 Sand Chamber 30 Volume that can be retained in the sand chamber (cubic feet) 3471 cf 4638 cf 5061 cf 11535 cf 31 Bottom of the sand chamber (fmsl) 760.50 752.00 745.50 747.50 32 Area of the sand chamber (square feet) 264 sf 518 sf 525 sf 1105 sf 33 Physical depth of the sand chamber (inches) 66 in 60 in 54 in 66 in 34 Ponding depth in the sand chamber, above any permanent pool (inches) 32 in 36 in 33 in 33 in 35 Elevation of the bypass device (fmsl) 765.15 756.50 749.50 752.50 36 Type of bypass device Outlet Control Structure Outlet Control Structure Spillway Spillway 37 Mechanism for distributing flow over the sand surface Slope bottom of pond towards sand bed Slope bottom of pond towards sand bed Slope bottom of pond towards sand bed Slope bottom of pond towards sand bed 38 Sand specification for sand chamber Clean washed concrete sand Clean washed concrete sand Clean washed concrete sand Clean washed concrete sand 39 Depth above underdrain pipe (inches) 21 in 21 in 21 in 21 in 40 Will the media be maintained to drain at least two inches per hour at the sand surface. Yes Yes Yes Yes 41 Is at least one clean -out pipe provided at the low point of each underdrain line? Yes Yes Yes Yes 42 Will clean -out pipes be capped? Yes Yes Yes Yes INFORMATION Please use this space to provide any additional information about the 43 Sand Filter(s): Stormwater control measures #14 are combined sand filter dry detention ponds with outlet control structures 1 1 Drainage area number 1 2 3 4 2 IDesign volume of SCM (cu ft 2565 sf 4955 sf 5124 sf 10709 sf GENERAL MDC FROM 02H .1050 3 Is the SCM sized to treat the SW from all surfaces at build -out? Yes Yes Yes Yes 4 Is the SCM located away from contaminated soils? Yes Yes Yes Yes 5 What are the side slopes of the SCM (H:V)? 3:1 3:1 3:1 3:1 6 Does the SCM have retaining walls, gabion walls or other engineered side slopes? No No Yes No 7 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? Yes Yes Yes Yes 8 Is there an overnow or bypass for inflow volume in excess of the design volume? Yes Yes Yes Yes 9 What is the method for dewatering the SCM for maintenance? Pump (preferred) Pump (preferred) Pump (preferred) Pump (preferred) 10 If applicable, will the SCM be cleaned out after construction? Yes Yes Yes Yes 11 Does the maintenance access comply with General MDC (8)? Yes Yes Yes Yes 12 Does the drainage easement comply with General MDC (9)? Yes Yes Yes Yes 13 If the SCM is on a single family lot, does (will?) the plat comply with General MDC (10)? Yes Yes Yes Yes 14 Is there an O&M Agreement that complies with General MDC (11)? Yes Yes Yes Yes 15 Is there an O&M Plan that complies with General MDC (12)? Yes Yes Yes Yes 16 Does the SCM follow the device specific MDC? Yes Yes Yes Yes 17 Was the SCM designed by an NC licensed professional? Yes Yes Yes Yes DRY POND MDC FROM 02H .1062 18 SHWT elevation (fmsl) TBD TBD TBD TBD 19 Elevation of the bottom of the dry pond (fmsl) 760.50 752.00 745.50 747.50 20 Distance from bottom to SHWT (feet) TBD TBD TBD TBD 21 Elevation of the temporary pool during the design storm (feet) 762.21 ft 753.77 ft 746.94 ft 749.24 ft 22 Ponding depth of the design storm (feet) 1.71 ft 1.77 ft 1.44 ft 1.74 ft 23 Will the dry pond be uniformly graded to flow toward the outlet? Yes Yes Yes Yes 24 Is a low flow channel being provided? No No No No 25 Are the inlet(s) and outlet located in a manner that avoids short-circuiting? Yes Yes Yes Yes 26 Will berms or baffles be provided to increase the flow path? Yes Yes Yes Yes 27 What method of pretreatment will be provided? Forebay Forebay Forebay Forebay 28 Diameter of drawdown orifice (in) - - - 29 Drawdown time for the temporary pool (hours) 51 60 69 69 30 Does the pond minimize impacts to the receiving channel from the 1-yr, 24-hr storm? Yes Yes Yes Yes 31 Is there a small permantent pool near the orifice to prevent clogging? No No No No 32 Will the outlet be designed to prevent clogging? Yes Yes Yes Yes 33 Are the dam and embankment planted in non- clumping turf grass? Yes Yes Yes Yes 34 Species of turf that will be used on the dam and embankment Centipede Grass Centipede Grass Centipede Grass Centipede Grass 35 Will trees and shrubs be prevented from growing on the dam and embankment? Yes Yes Yes Yes FIONAL INFORMATION Please use this space to provide any additional 36 information about the infiltration system(s): he sand filters are combined with the dry ponds, the sand ed acts as the low flow orifice BAYFILTER 1 1 Drainage area number 5 6 7 8 9 2 Design volume (cu ft) or peak treatment rate (cfs) of SCM 2898 cf 10332 cf 14136 cf 10026 cf 17428 cf GENERAL MDC FROM 02H .1050 3 Is the SCM sized to treat the SW from all surfaces at build- out? Yes Yes Yes Yes Yes 4 Is the SCM located away from contaminated soils? Yes Yes Yes Yes Yes 5 What are the side slopes of the SCM (H:V)? 6 Does the SCM have retaining walls, gabion walls or other engineered side slopes? No No No No No 7 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? Yes Yes Yes Yes Yes 8 Is there an overflow or bypass for inflow volume in excess of the design volume? Yes Yes Yes Yes Yes 9 What is the method for dewatering the SCM for maintenance? Pump (preferred) Pump (preferred) Pump (preferred) Pump (preferred) Pump (preferred) 10 If applicable, will the SCM be cleaned out after construction? Yes Yes Yes Yes Yes 11 Does the maintenance access comply with General MDC (8)? Yes Yes Yes Yes Yes 12 Does the drainage easement comply with General MDC (9)? Yes Yes Yes Yes Yes 13 If the SCM is on a single family lot, does (will?) the plat comply with General MDC (10)? Yes Yes Yes Yes Yes 14 Is there an O&M Agreement that complies with General MDC (11)? Yes Yes Yes Yes Yes 15 Is there an O&M Plan that complies with General MDC (12)? Yes Yes Yes Yes Yes 16 Does the SCM follow the device specific MDC? Yes Yes Yes Yes Yes 17 Was the SCM designed by an NC licensed professional? Yes Yes Yes Yes Yes BAYFILTER MDC FROM THE STORMWATER DESIGN MANUAL 18 If Volume Design is used, what is the volume from the drainage area (cubic feet)? 2898 cf 10332 cf 14136 cf 10026 cf 17428 cf 19 Is an upstream detention used? Yes Yes Yes Yes Yes 20 Volume of the upslope detenion system (cubic feet) 3004 cf 10676 cf 14177 cf 10220 cf 17911 cf 21 Percent of the design volume contained in the upslope detention system (%) 100% 100% 100% 100% 100% 22 If Rate Based Sizing is used, for 1 inch or 1.5 inch (Coastal areas). Water Quality flow rate for drainage area (cfs) 23 Number of cartridges 2 8 12 9 16 24 Cartridge height (inches) 34 in 22 in 22 in 22 in 22 in 25 SHWT elevation (fmsl) TBD TBD TBD TBD TBD 26 Elevation of bottom of BayFilter vault (fmsl) 746.50 731.30 736.60 749.60 728.00 27 Clearance from the SHWT (feet) TBD TBD TBD TBD TBD 28 BayFilter Media Flow Rate (GPM/ft2 of Media Surface) .33 gpm/sf .5 gpm/sf .5 gpm/sf .5 gpm/sf 1 gpm/sf 29 Does the system includes a sediment sump? No No No No No 30 If yes, the diameter of the sump (feet) 31 If yes, the depth of the sump (feet) 32 Time to drain the sump (hours) 33 Time to drain the BayFilter (hours) 27 hrs 48 hrs 48 hrs 48 hrs 48 hrs 34 Is an off-line flow splitting device used? Yes Yes Yes Yes Yes 35 Type of media used (EMC or GAC-metals) EMC EMC EMC EMC EMC 36 Will maintenance be performed by Certified Maintenance providers per instructions? Yes Yes Yes Yes Yes ADDITIONAL INFORMATION 37 Please use this space to provide any additional information about the BayFilter system(s): All Bayfilters are placed downstream of StormTech chamber detention system that is sized for the 1-inch water quality volume. A flow splitter manhole is placed upstream of the detention system to allow higher flow events to bypass the detention & treatment system.