20181476 Ver 1_SCM Supplements_20181030

WET POND
1
Drainage area number Sub 1 To SCM A
Total coastal wetlands area (sq ft) - Parking / driveway (sq ft)
Total surface water area (sq ft) - Sidewalk (sq ft)
Total drainage area (sq ft) 2863410 sf - Roof (sq ft)
BUA associated with existing development (sq ft) - Roadway (sq ft)
Proposed new BUA (sq ft) 710198 sf - Other, please specify in the comment box below (sq ft)
Percent BUA of drainage area 25%Total BUA (sq ft)710198 sf
Design rainfall depth (in) 1.0 in
Minimum volume required (cu ft) 65196 cf
Design volume of SCM (cu ft) 161050 cf
#1 Is the SCM sized to treat the SW from all surfaces at build-out? No #7 If applicable, with the SCM be cleaned out after construction?Yes
#2 Is the SCM located on or near contaminated soils? No #8 Does the mainetenance access comply with General MDC (8)?Yes
#3 What are the side slopes of the SCM (H:V)? 3:1 #9 Does the drainage easement comply with General MDC (9)?Yes
#3 Does the SCM have retaining walls, gabion walls or other engineered side slopes?No #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)?Yes
#4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? Yes #11 Is there an O&M Agreement that complies with General MDC (11)?Yes
#5 Is there a a bypass for flows in excess of the design flow? No #12 Is there an O&M Plan that complies with General MDC (12)?Yes
#6 What is the method for dewatering the SCM for maintenance?Drawdown Orifice #13 Was the SCM designed by an NC licensed professional?Yes
#1 Method used SA/DA #6 Width of the vegetated shelf (feet)6 ft
#1 Surface area of the main permanent pool (square feet) 41473 sf #6 Location of vegetated shelf Above Normal Pool
#1 Volume of the main permanent pool (cubic feet) 161050 cf #6 Elevation of top of shelf (fmsl)833.50 ft
#2 Average depth of the main pool (feet) 3.9 ft #6 Elevation of bottom of shelf (fmsl)
832.50 ft
#2 Was the vegetated shelf included in the calculation of average depth? No #6 Slope of vegetated shelf (H:V)
6:1
#2 Elevation of the bottom of the permanent pool (fmsl) 828 ft #7 Diameter of drawdown orifice (inches)
5.0 in
#2 Elevation of the top of the permanent pool (fmsl) 832.50 ft #7 Drawdown time for the temporary pool (hours)
63 hrs
#2 Elevation of the top of the temporary pool (fmsl) 833.52 ft #7 Does the orifice drawdown from below the top surface of the permanent pool?
Yes
#3 Depth provided for sediment storage (inches) 6 in
#8 Does the pond minimize impacts to the receiving channel from the 1-yr, 24-hr storm? Yes
#4 Are the inlet(s) and outlet located in a manner that avoids short-circuiting?Yes #9 Are fountains proposed? No
#9 If yes, is documentation provided per Wet Pond MDC (9)?
#10 Is a trash rack or other device provided to protect the outlet system? Yes
#5 Volume of the forebay (cubic feet) 62756 cf
#11 Are the dam and embankment planted in non-clumping turf grass? Yes
#5 Is this 15-20% of the volume in the main pool? Yes
#11 Species of turf that will be used on the dam and embankment Tall Fescue
#5 Depth of forebay at entrance (inches) 54 in
#11 Describe the planting plan for the vegetated shelf:
#5 Depth of forebay at exit (inches) 54 in
#5 Does water flow out of the forebay in a non-erosive manner? Yes
#5 Clean-out depth for forebay (inches) 6 in
#5 Will the forebay be cleaned out when the depth is reduced to less than the above? Yes
Howard Property
Break down of BUA in the drainage area (both new and existing):
COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM
Stormwater program(s) that apply (please specify):
Minimum Design Criteria standards set forth in the NC DEQ Stormwater Manual
WET POND MDC FROM 02H .1053
#4 Describe any measures, such as berms or baffles, that will be taken to improve the flow path:
Three shallow land species and three shallow water species are specified. Detailed planting instructions are included.
ADDITIONAL INFORMATION
Please use this space to provide any additional information about this wet pond that you think is relevant to the review:
GENERAL MDC FROM 02H .1050
THE DRAINAGE AREA
Wet Pond 1 3:47 PM 10/29/2018
WET POND Howard Property
2
Drainage area number Sub 1 to SCM B
Total coastal wetlands area (sq ft) - Parking / driveway (sq ft)
Total surface water area (sq ft) - Sidewalk (sq ft)
Total drainage area (sq ft) 782809 sf - Roof (sq ft)
BUA associated with existing development (sq ft) - Roadway (sq ft)
Proposed new BUA (sq ft) 308239 sf - Other, please specify in the comment box below (sq ft)
Percent BUA of drainage area 39%Total BUA (sq ft)308239 sf
Design rainfall depth (in) 1.0 in
Minimum volume required (cu ft) 26380 cf
Design volume of SCM (cu ft)49485 cf
#1 Is the SCM sized to treat the SW from all surfaces at build-out? No #7 If applicable, with the SCM be cleaned out after construction?Yes
#2 Is the SCM located on or near contaminated soils? No #8 Does the mainetenance access comply with General MDC (8)?Yes
#3 What are the side slopes of the SCM (H:V)? 3:1 #9 Does the drainage easement comply with General MDC (9)?Yes
#3 Does the SCM have retaining walls, gabion walls or other engineered side slopes?No #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)?Yes
#4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? Yes #11 Is there an O&M Agreement that complies with General MDC (11)?Yes
#5 Is there a a bypass for flows in excess of the design flow? No #12 Is there an O&M Plan that complies with General MDC (12)?Yes
#6 What is the method for dewatering the SCM for maintenance?Drawdown Orifice #13 Was the SCM designed by an NC licensed professional?Yes
#1 Method used SA/DA #6 Width of the vegetated shelf (feet)6 ft
#1 Surface area of the main permanent pool (square feet) 10288 sf #6 Location of vegetated shelf Above Normal Pool
#1 Volume of the main permanent pool (cubic feet) 49485 cf #6 Elevation of top of shelf (fmsl)826 ft
#2 Average depth of the main pool (feet) 4.8 ft #6 Elevation of bottom of shelf (fmsl)
825 ft
#2 Was the vegetated shelf included in the calculation of average depth? No #6 Slope of vegetated shelf (H:V)
6:1
#2 Elevation of the bottom of the permanent pool (fmsl) 818 ft #7 Diameter of drawdown orifice (inches)
2.5 in
#2 Elevation of the top of the permanent pool (fmsl) 825.00 ft #7 Drawdown time for the temporary pool (hours)
51 hrs
#2 Elevation of the top of the temporary pool (fmsl) 826.57 ft #7 Does the orifice drawdown from below the top surface of the permanent pool?
Yes
#3 Depth provided for sediment storage (inches) 6 in
#8 Does the pond minimize impacts to the receiving channel from the 1-yr, 24-hr storm? Yes
#4 Are the inlet(s) and outlet located in a manner that avoids short-circuiting?Yes #9 Are fountains proposed? No
#9 If yes, is documentation provided per Wet Pond MDC (9)?
#10 Is a trash rack or other device provided to protect the outlet system? Yes
#5 Volume of the forebay (cubic feet) 14121
#11 Are the dam and embankment planted in non-clumping turf grass? Yes
#5 Is this 15-20% of the volume in the main pool? Yes
#11 Species of turf that will be used on the dam and embankment Tall Fescue
#5 Depth of forebay at entrance (inches) 84 in
#11 Describe the planting plan for the vegetated shelf:
#5 Depth of forebay at exit (inches) 84 in
#5 Does water flow out of the forebay in a non-erosive manner? Yes
#5 Clean-out depth for forebay (inches) 6 in
#5 Will the forebay be cleaned out when the depth is reduced to less than the above? Yes
ADDITIONAL INFORMATION
Please use this space to provide any additional information about this wet pond that you think is relevant to the review:
GENERAL MDC FROM 02H .1050
THE DRAINAGE AREA
WET POND MDC FROM 02H .1053
#4 Describe any measures, such as berms or baffles, that will be taken to improve the flow path:
Three shallow land species and three shallow water species are specified. Detailed planting instructions are included.
Break down of BUA in the drainage area (both new and existing):
COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM
Stormwater program(s) that apply (please specify):
Minimum Design Criteria standards set forth in the NC DEQ Stormwater Manual
Wet Pond 1 3:47 PM 10/29/2018