SW3190201_SSW-SuppEZ-20170329-DEMLR-SW_20190212

BIORETENTION CELL
1
Drainage area number POI1
Total coastal wetlands area (sq ft) sf - Parking / driveway (sq ft)
Total surface water area (sq ft) sf - Sidewalk (sq ft)
Total drainage area (sq ft)87556 sf - Roof (sq ft)
BUA associated with existing development (sq ft)40511 sf - Roadway (sq ft)
Proposed new BUA (sq ft)30492 sf - Other, please specify in the comment box below (sq ft)
Percent BUA of drainage area 81%Total BUA (sq ft)51494 sf
Design rainfall depth (in)1.0 in
Minimum volume required (cu ft)1830 cf
Design volume of SCM (cu ft)1830 cf
#1 Is the SCM sized to treat the SW from all surfaces at build-out?Yes #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)?2:1 #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? Yes #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)?
#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?Other #13 Was the SCM designed by an NC licensed professional?Yes
#1 SHWT elevation (fmsl)<557.5 ft.#6 Percentage of medium to coarse washed sand by volume 75%
#1 Bottom of the bioretention cell (fmsl)559 ft #6 Percentage of fines (silt and clay) by volume 15%
#1 Distance from bottom to SHWT (feet)>1.5 ft.#6 Percentage of organic matter by volume 10%
#2 Surface area of the bioretention cell (square feet)1499 sf #6 Type of organic material Mulch
#2 Design volume of the bioretention cell (cubic feet)2309 cf #7 Phosphorus Index (P-Index) of media (unitless) <30
#2 Ponding depth of the design storm (inches)562 in #8 Will compaction be avoided during construction?Yes
#3 Is the bioretention cell used for peak attenuation?Yes #9 Will cell be maintained to a one inch/hour standard?Yes
#3 Depth of peak attenuation over planting surface (in)11 in #10 Describe the planting plan:
#3 Height of peak attenuation outlet above the planting surface (in)16 in
#4 Infiltration rate of the in situ soil (inch/hour)N/A
#4 Diameter of the underdrain pipes (if applicable)4 in
#4 Does the design include Internal Water Storage (IWS)?Yes #11 Depth of mulch, if applicable (inches)2 in
#4 if so, elevation of the top of the IWS (fmsl)560 ft #11 Type of mulch, if applicable Hardwood
#4 Elevation of the planting surface (fmsl)562 ft #12 How many clean out pipes are being installed?1
#5 Will the cell contain trees and shrubs?No #12 Briefly describe the pretreatment that will be used:
#5 Media depth (inches)30 in
THE DRAINAGE AREA
BIORETENTION CELL MDC FROM 02H .1052
Planting surface elevation is 561.5' - spreadsheet rounds up.
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):
NCDEQ
GENERAL MDC FROM 02H .1050
ADDITIONAL INFORMATION
Please use this space to provide any additional information about this bioretention cell that you think is relevant to the review:
Sweetflag to be planted above media mix that conforms to NCDEQ standards. See sheet C3.7 and L1.1 on plans for
additional information
Manhole with sump will be implemented to achieve pre-treatment
O'Reilly Wingate
Bioretention 1 3:36 PM 1/25/2019