20170314 Ver 3_Supplement Form - Level Spreader C_20181113

LEVEL SPREADER - FILTER STRIP (LS-FS)
1
Drainage area number Sub 1 to SWMF C
Total coastal wetlands area (sq ft) - Parking / driveway (sq ft)21229 sf
Total surface water area (sq ft) - Sidewalk (sq ft)9363 sf
Total drainage area (sq ft)433981 sf - Roof (sq ft)
BUA associated with existing development (sq ft)141099 sf - Roadway (sq ft)
Proposed new BUA (sq ft)30592 sf - Other, please specify in the comment box below (sq ft)141099 sf
Percent BUA of drainage area 39.6%Total BUA (sq ft)171691 sf
Design rainfall depth (in)1.0 in
Minimum volume required (cu ft)
Design volume of SCM (cu ft)
#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)?#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?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?#13 Was the SCM designed by an NC licensed professional?Yes
#1 Length of level spreader (feet)42.3 ft #7 Height of the drop from the level spreader to the transition zone (inches)12.0 in
#2 LS-FS receives flow from The drainage areas #7 Width of the transition zone (inches)36.0 in
#2 Flow rate to LS-FS during design storm (cfs)4.23 cfs #7 Protection for the transition zone Aggregate
#2 Is a bypass device provided?Yes #8 Width of the filter strip (feet)30 ft
#9 Is the filter strip free of draws and channels?Yes
#9 Has this been verified in the field?No
#3 Is this LS-FS designed to receive flow from the drainage area during the 10-year storm?No #10 Slope of the filter strip (%)3.3%
#4 Has a blind swale been provided?Yes #10 Is this slope uniform across the entire filter strip?Yes
#4 Does the blind swale provide for uniform overtopping of the level spreader?Yes #10 Will the first 12" of soil be adjusted if needed to promote plant growth?Yes
#5 What material will be used for the level spreader?Concrete #10 Will the filter strip and side slopes be planted with non-clumping, deep-rooted sod?Yes
#5 Will the construction tolerance be <0.25 inch along the level spreader length?Yes #10 Species of sod that will be used Tall Fescue
#6 Will the level spreader be straight or convex in plan view?Yes #10 Will soil be temporarily stabilized until permanent vegetation is established?Yes
THE DRAINAGE AREA
Other catergory in breakdown of BUA refers to all existing impervious area offsite of project area, but within the sub-basin.
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):
Stormwater Rules and Regulations found in 15A NCAC 02H .1059
GENERAL MDC FROM 02H .1050
LS-FS MDC FROM 02H .1059
#2 If yes, describe the bypass device:
Splitter Box
ADDITIONAL INFORMATION
Please use this space to provide any additional information about this LS-FS that you think is relevant to the review:
LEY-15010 - Twin Lakes Center
LS-FS 4 10:15 AM 7/18/2018