SW3200102_Copy of SSW-SuppEZ-20170329-DEMLR-SW_1/17/2020

SAND FILTER
Heilig Road Building Expansion
THE DRAINAGE AREA 7
Drainage area number 1 Break down of BUA in the drainage area (both new and existing):
Total coastal wetlands area (sq ft)
n/a
Parking / driveway (sq ft)
50981 sf
Total surface water area (sq ft)
n/a
Sidewalk (sq ft)
1065 sf
Total drainage area (sq ft)
89735 sf
Roof (sq ft)
sf
BUA associated with existing development (sq ft)
52046 sf
Roadway (sq ft)
sf
Proposed new BUA (sq ft)
sf
Other, please specify in the comment box below (sq ft)
I sf
Percent BUA of drainage area
58 %
ITotal BUA (sq ft)
16988 sf
COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM
Stormwater program(s) that apply (please specify):
Design rainfall depth (in)
1.0 in
Phase II
Minimum volume required (cu ft)
4262 cf
Design volume of SCM (cu ft)
17297 cf
GENERAL MDC FROM 02H .1050 JIM
#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)?
3:1
#9 Does the drainage easement complywith 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)?
No
#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?
Yes
#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
1#13 Was the SCM designed by an NC licensed professional?
Yes
SAND FILTER MDC FROM 02H .1056
#1 SHWT elevation (fmsl)
800 It
#3 Volume of stormwater from drainage area during design storm (cubic feet)
4262 cf
#1 Type of sand fitter (open or closed)
Open
#3 Total volume that can be stored above the sediment and sand chambers (cubic feet)
17297 cf
#1 If closed, describe if the fitter will be pre -cast or pour -in -place:
#3 Is this sand filter designed to attenuate peak flows?
yes
n/a
#3 Elevation of the bypass device (fmsl)
81129
#1 If closed, top of grate elevation (fmsl)
n/a
#3 Describe the bypass device:
#2 Volume that can be retained in the sediment chamber (cubic feet)
8752 cf
4'x4' concrete riser with primary spillway. Orifice Control for 2 and 10 year, 24 hour storms
#2 Will there be a permanent pool in the sediment chamber?
No
#2 Bottom of the sediment chamber (fmsl)
811 It
#4 Ponding depth from the top of the sand to the bypass device (ft) Varies, See Calcs
#2 Area of the sediment chamber (square feet)
1697 sf
#5 Describe the mechanism for distributing flow over the sand surface:
#2 Physical depth of the sediment chamber (inches)
36 in
Check Dam Weir
#2 Ponding depth in the sediment chamber, above any permanent pool (inches)
Varies, See Calcs
#6 Sand specification for sand chamber
#2 Elevation of top of weir between chambers (fmsl)
809 It
ASTM-C-144 or ASM-C-33 concrete sand
#2 Volume that can be retained in the sand chamber (cubic feet)
8545 cf
#2 Bottom of the sand chamber (fmsl)
810 It
#7 Depth above underdrain pipe (inches)
12 in
#2 Area of the sand chamber (square feet)
898 sf
#8 Will the media be maintained to drain at least two inches per hour at the sand surface?
Yes
#2 Physical depth of the sand chamber (inches)
48 in
#9 Is at least one clean -out pipe provided at the low point of each underdrain line?
Yes
#2 Ponding depth in the sand chamber, above any permanent pool (inches)
Varies, See Calcs
1#9 Will clean -out pipes be capped?
Yes
ADDITIONAL INFORMATION III E
Please use this space to provide any additional information about this sand fitter that you think is relevant to the review:
Sand Filter 1 1:18 PM 1/17/2020

Sand Filter 2 1:18 PM 1/17/2020