SW3240205_Supplement-EZ Form_20240307

SUPPLEMENT-EZ COVER PAGE
!OHMS LOADED i
PROJECT INFORMATION
1_Project Name _ Courtyards on the Greenway _
2 Project Area(ac) _ _ 49.12 _
3 Coastal Wetland Area(ac) 0
4 Surface Water Area(Sc) _ 0.41
5 Is this project High or Low Density? High
6 Does this project use an off-site SCM? No
COMPLIANCE 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.100319(CTd)? Yes
10 Is streambank stabilization proposed on this project? No
NUMBER AND TYPE OF SCMs:
11 Infiltration System
12 Bioretention Cell
13 Wet Pond 2
14 Stormwater Wetland
15 Permeable Pavement _
16 Sand Filter _
17 Rainwater Harvesting(RWH) _
18 Green Roof _
19 Level Spreader-Filter Strip(LS-FS)
20 Disconnected Impervious Surface(DM)
21 Treatment Swale
22 Dry Pond
23 StormFilter
24 Silva Cell
25 Beyfilter
26 Filterra
FORMS LOADED
DESIGNER CERTIFICATION
27 Name and Title: Andrew Allison,P.E.-Project Manager
28 Organization: Timmons Group
29 Street address: _ 610 East Morehead Street,Suite 250
30 C!t't r,State,Zip: Charlotte,NC,28202
31 Phone number(a): [phone]
32 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.
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Seal Date

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(sa ft) 1,990,692 967,032 483,516
7 Offslte drainage area(sgft) 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) 563601 sf 353848 sf 209753 sf
New BUA not on subdivided lots(subject to
10 permitting)(sf) 195933 sf 137749 sf 51171 sf
11 Offsite BUA(sq ft) We 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) 53617 sf 39787 sf 13830 sf
-Roof(sg.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"/0 51% 54%
19 Design storm(inches) - 3.6 in 3.6 in 3.6 in
20 Design volume of SCM(Cu ft) 415412 cf 319550 cf 95852 cf
21 f Calculation method for design volume Surface Area Surface Area Surface Area
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 drainage area(s):

WET POND
1Drainage area number I 1 2
2 Minimum required treatment volume(Cu ft)
E gout.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
&What are the side slopes of the SCM(H:V)? 3:1 31
6 Does the SCM have retaining walls,gabion walls or other engineered No No
side slopes?
Are the inlets,outlets,and receiving stream protected from erosion
7(10-year storm)? Yes Yes
Is there an overflow or bypass for inflow volume in excess of the
a design volume? Yes Yes
9 What is the method for dewatering the SCM for maintenance? Drawdown Orifice 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
13 If the SCM is on a single family lot,does(will?)the plat comply with 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
_2 Was the SCM designed by an NC licensed professional? Yes Yes •
wit e9Np MDC FROM 02H.105.3
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) 625.71 828.36
26 Surface area of the main permanent pool(square feet) 38768 14375
27 Volume of the main permanent pool(cubic feet) 148129 cf 22248 cf
28 Average depth of the main pool(feet) 5.12 ft 3.35 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) 39583 cf 10559 cf
33 Is this 15-20%of the volume in the main pool? No No
34 Clean-out depth for forebay(inches) 78 in 54 in
35 Design volume of SCM(cu ft) 319560 cf 95852 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) 4 3
41 Are the inlet(s)and outlet located in a manner that avoids short- 1 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 foreb y 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?
Are fountains proposed?(If Y,please provide documentation that
50 MDC(9)is met.) Yes No
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
ADDIT ONAL INFORMATION
55,Please use this space to provide any additional information about the
wet pond(s):
2