SW3240205_Supplement-EZ Form_20240621

FORMS LOADED
DJECT INFORMATION
1 Project Name I Courtyards on the Greenway
2 Project Area(ac) 49.12
3 Coastal Wetland Area(ac) 0
4 Surface Water Area(ac) 0.41 _
5 Is this project High or Low Density? High -
6 Does this project use an off-site SCM? No
MPLIANCE WITH 02H.1003(4)
7 Width of vegetated setbacks provided(feet) 100
8 Will the vegetated setback remain vegetated? Yes
9 If BUA is proposed in the setback,does it meet NCAC 02H.1003(4)(c-d)? i Yes
0 Is streambank stabilization proposed on this project? No
MBER AND TYPE OF SCMs:
1 Infiltration System
2 Bioretention Cell
3 Wet Pond I 2
4 Stormwater Wetland
5 Permeable Pavement
6 Sand Filter
7 Rainwater Harvesting(RWH)
8 Green Roof
9 Level Spreader-Filter Strip(LS-FS)
0 Disconnected Impervious Surface(DIS)
1 Treatment Swale _-
2 Dry Pond -_
3 StormFilter
4 Silva Cell
5 Bayfilter
6 Filterra
FORMS LOADED
SIGNER CERTIFICATION
7 Name and Title: _ _ _ Andrew Allison,P.E.-Project Manager
8 Organization: Timmons Group
9 Street address: 610 East Morehead Street,Suite 250 _
0 City,State,Zip: Charlotte,NC,28202 _
1 Phone number(s): [phone] -
2 Email: [e-mail]
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.
Designer
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DRAINAGE AREAS
1 Is this a high density project? Yes
2 If so,number of drainage areas/SCMs _ 2
3 Does this project have low density areas? _ No
4 If so,number of low density drainage areas _ 0
Is all/part of this project subject to previous rule
5 versions? No
FORMS LOADED
DRAINAGE AREA INFORMATION Entire Site 1 2
4 Type of SCM n/a Wet Pond Wet Pond _
5 Total drainage area(sq ft) 1,990,692 967,032 483,516
6 Onsite drainage area(sq ft) 1,990,692 967,032 483,516
7 Offsite drainage area(sq ft) 0 0 0
8 Total BUA in project(sq ft) 758380 sf 497456 sf 260924 sf
New BUA on subdivided lots(subject to
9 permitting)(sq ft) 560400 sf 351543 sf 208857 sf
New BUA not on subdivided lots(subject to
10 permitting)(sf) 199134 sf 140054 sf 52067 sf
11 Offsite BUA(sq ft) n/a n/a n/a
12 Breakdown of new BUA not on subdivided lots:
-Parking(sq ft) 7013 sf 7013 sf n/a
-Sidewalk(sq ft) 56818 sf 42092 sf 14726 sf
-Roof(sq ft) 10050 sf 3037 sf n/a
-Roadway(sq ft) 125253 sf 87912 sf 37341 sf
-Future(sq ft) n/a n/a n/a
-Other,please specify in the comment box
below(sq ft) n/a n/a n/a
New infiltrating permeable pavement on
13 subdivided lots(sq ft) n/a n/a n/a
New infiltrating permeable pavement not on
14 subdivided lots(sq ft) n/a n/a n/a
Existing BUA that will remain(not subject to
15 permitting)(sq ft) 5859 sf 5859 sf n/a
16 Existing BUA that is already permitted(sq ft) n/a n/a n/a
17 Existing BUA that will be removed(sq ft) 31918 sf 31918 sf n/a
18 Percent BUA 38% 51% 54%
19 Design storm(inches) 2.9 in 2.9 in
20 Design volume of SCM(cu ft) 319560 cf 95852 cf
21 Calculation method for design volume Simple Method Simple Method
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 drainage area(s):

WET POND
I 1 Drainage area number 1 2 I
2 Minimum required treatment volume(Cu ft) 120708 cf 62919 cf
GENERAL MDC FROM 02H.1050
3 Is the SCM sized to treat the SW from all surfaces at build-out? Yes Yes
4 Is the SCM located away from contaminated soils? Yes Yes
5 What are the side slopes of the SCM(H:V)? 3:1 3:1
6 Does the SCM have retaining walls,gabion walls or other engineered No No
side slopes?
7 Are the inlets,outlets,and receiving stream protected from erosion Yes Yes
(10-year storm)?
8 Is there an overflow or bypass for inflow volume in excess of the Yes Yes
design volume?
9 What is the method for dewatering the SCM for maintenance? Pump(preferred) Pump(preferred)
10 If applicable,will the SCM be cleaned out after construction? Yes Yes
11 Does the maintenance access comply with General MDC(8)? Yes Yes
12 Does the drainage easement comply with General MDC(9)? Yes Yes
If the SCM is on a single family lot,does(will?)the plat comply with
13 N/A N/A
General MDC(10)?
14 Is there an O&M Agreement that complies with General MDC(11)? Yes Yes
15 Is there an O&M Plan that complies with General MDC(12)? Yes Yes
16 Does the SCM follow the device specific MDC? Yes Yes
17 Was the SCM desi.ned b an NC licensed•rofessional? Yes Yes
WET POND MDC FROM 02H.1053
18 Sizing method used SA/DA SA/DA
19 Has a stage/storage table been provided in the calculations? Yes Yes
20 Elevation of the excavated main pool depth(bottom of sediment 615.50 619.50
removal)(fmsl)
21 Elevation of the main pool bottom(top of sediment removal)(fmsl) 616.00 620.00
22 Elevation of the bottom of the vegetated shelf(fmsl) 622.00 624.00
23 Elevation of the permanent pool(fmsl) 622.50 624.50
24 Elevation of the top of the vegetated shelf(fmsl) 623.00 625.00
25 Elevation of the temporary pool(fmsl) 626.00 628.50
26 Surface area of the main permanent pool(square feet) 35957 8228
27 Volume of the main permanent pool(cubic feet) 160682 cf 22891 cf
28 Average depth of the main pool(feet) 4.90 ft 3.40 ft
29 Average depth equation used Equation 3 Equation 3
30 If using equation 3,main pool perimeter(feet) 1026.0 ft 456.0 ft
31 If using equation 3,width of submerged veg.shelf(feet) 5.0 ft 5.0 ft
32 Volume of the forebay(cubic feet) 24526 cf 4042 cf
33 Is this 15-20%of the volume in the main pool? Yes Yes
34 Clean-out depth for forebay(inches) 78 in 54 in
35 Design volume of SCM(cu ft) 308691 cf 118174 cf
36 Is the outlet an orifice or a weir? Weir Weir
37 If orifice,orifice diameter(inches) n/a n/a
38 If weir,weir height(inches) n/a n/a
39 If weir,weir length(inches) 48 in 48 in
40 Drawdown time for the temporary pool(days) 5 3
41 Are the inlet(s)and outlet located in a manner that avoids short- Yes Yes
circuiting?
42 Are berms or baffles provided to improve the flow path? No No
43 Depth of forebay at entrance(inches) 78 in 54 in
44 Depth of forebay at exit(inches) 72 in 48 in
45 Does water flow out of the forebay in a non-erosive manner? Yes Yes
46 Width of the vegetated shelf(feet) 10 ft 10 ft
47 Slope of vegetated shelf(H:V) 10:1 10:1
48 Does the orifice drawdown from below the top surface of the No No
permanent pool?
49 Does the pond minimize impacts to the receiving channel from the 1- Yes Yes
yr,24-hr storm?
50 Are fountains proposed?(If Y,please provide documentation that Yes No
MDC(9)is met.)
51 Is a trash rack or other device provided to protect the outlet system? Yes Yes
52 Are the dam and embankment planted in non-clumping turf grass? Yes Yes
53 Species of turf that will be used on the dam and embankment Hybrid Bermuda Hybrid Bermuda
54 Has a planting plan been provided for the vegetated shelf? Yes Yes
ADDITIONAL INFORMATION
55 Please use this space to provide any additional information about the
wet pond(s):
2