SW6231111_Supplement-EZ Form_20231128

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name Percival Square Apartments
2 Project Area(ac) 4.93
3 Coastal Wetland Area(ac) 0
4 Surface Water Area(ac) 0
5 Is this project High or Low Density? _—_ High
6 Does this project use an off-site SCM? l No
COMPLIANCE WITH 02H.1003(4)
7 Width of vegetated setbacks provided(feet) 20
8 Will the vegetated setback remain vegetated? Yes
9 I if BUA is proposed in the setback,does it meet NCAC 02H.1003(4)(c-d)? N/A_
10 Is streambank stabilization proposed on this project? No
NUMBER AND TYPE OF SCMs:
11 Infiltration System 0
12 i Bioretention Cell 0
13 'Wet Pond 1
14 Stormwater Wetland 0
15 Permeable Pavement 0
16 Sand Filter 0
17 Rainwater Harvesting(RWH) 0
_18 Green Roof 0
19 Level Spreader-Filter Strip(LS-FS) 0
20 Disconnected Impervious Surface(DIS) 0
21 Treatment Swale 0
22 Dry Pond _ 0
23 StormFilter 0
24 Silva Cell 0
25 Bayfilter 0
26 Filterra 0
FORMS LOADED
DESIGNER CERTIFICATION
• 27 Name and Title: Matt Lowder
28 Organization: Bowman North Carolina Ltd.
29 Street address: 4006 Barrett Drive,Suite 104
30 Ci State,Zip: Raleigh,NC 27609
®Phone number(s)_ [phone]
®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 ;diffffA
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Seal Date

DRAINAGE AREAS
1 Is this a high density project? Yes
2 If so,number of drainage areas/SCMs 1
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
4 Type of SCM - Wet Pond
5 Total drainage area(sq ft) 214615 147582
6 Onsite drainage area(sq ft) 214615 147582 _
7 Offsite drainage area(sq ft) 0 0
8 Total BUA in project(sq ft) sf 85318 sf _
New BUA on subdivided lots(subject to permitting)
9 (sq ft)New BUA not on subdivided lots(subject to
10 permitting)(sf)
11 Offsite BUA(sq ft) -
12 Breakdown of new BUA not on subdivided lots:
-Parking(sq ft) 18030 sf
-Sidewalk(sq ft) 9379 sf
-Roof(sq ft) 29736 sf
-Roadway(sq ft) 28090 sf
-Future(sq ft) sf
-Other,please specify in the comment box
below(sq ft)
New infiltrating permeable pavement on
13 subdivided lots(sq ft) sf
New infiltrating permeable pavement not on
14 subdivided lots(sq ft) sf
Existing BUA that will remain(not subject to
15 permitting)(sq ft) sf
16 Existing BUA that is already permitted(sq ft) sf
17 Existing BUA that will be removed(sq ft) sf
18 Percent BUA 58%
19 Design storm(inches) 1 in
20 Design volume of SCM(cu ft) 15866 cf
21 Calculation method for design volume Simple Method
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 drainage area(s):

WET POND
I Drainage area number 1 I
2 Minimum required treatment volume(Cu ft) 15866 cf
GENERAL MDC FROM 02H.1050
3'Is the SCM sized to treat the SW from all surfaces at build-out? Yes
4 Is the SCM located away from contaminated soils? Yes
5 What are the side slopes of the SCM(H:V)? 3:1
6 Does the SCM have retaining walls,gabion walls or other engineered No
side slopes?
Are the inlets,outlets,and receiving stream protected from erosion
7 Yes
(10-year storm)?
8 Is there an overflow or bypass for inflow volume in excess of the Yes
design volume?
9 What is the method for dewatering the SCM for maintenance? Pump(preferred)_
10 If applicable,will the SCM be cleaned out after construction? Yes
11 Does the maintenance access comply with General MDC(8)? Yes
12 Does the drainage easement comply with General MDC(9)? Yes
13 If the SCM is on a single family lot,does(will?)the plat comply with N/A
General MDC(10)?
14 Is there an O&M Agreement that complies with General MDC(11)? Yes
15 Is there an O&M Plan that complies with General MDC(12)? Yes
16 Does the SCM follow the device specific MDC? Yes
17 Was the SCM desi ned b an NC licensed rofessional? Yes
WET POND MDC FROM 02H.1053
18 Sizing method used SA/DA
19 Has a stage/storage table been provided in the calculations? Yes
20 Elevation of the excavated main pool depth(bottom of sediment 239.00
removal)(fmsl)
21 Elevation of the main pool bottom(top of sediment removal)(fmsl) 240.00
22 Elevation of the bottom of the vegetated shelf(fmsl) 245.50
23 Elevation of the permanent pool(fmsl) 246.00
24 Elevation of the top of the vegetated shelf(fmsl) 246.50
25 Elevation of the temporary pool(fmsl) 248.10
26 Surface area of the main permanent pool(square feet) 3670
27 Volume of the main permanent pool(cubic feet) 15598 cf
28 Average depth of the main pool(feet) 4.20 ft
29 Average depth equation used Equation 3
30 If using equation 3,main pool perimeter(feet) 260.0 ft
31 If using equation 3,width of submerged veg.shelf(feet) 3.0 ft
32 Volume of the forebay(cubic feet) 2443 cf
33 Is this 15-20%of the volume in the main pool? Yes
34 Clean-out depth for forebay(inches) 12 in
35 Design volume of SCM(cu ft) 15866 cf
36 Is the outlet an orifice or a weir? Orifice
37 If orifice,orifice diameter(inches) 1.3 in
38 If weir,weir height(inches)
39 If weir,weir length(inches)
40 Drawdown time for the temporary pool(days) 3.91
41 Are the inlet(s)and outlet located in a manner that avoids short- Yes
circuiting? _
42 Are berms or baffles provided to improve the flow path? Yes
43 Depth of forebay at entrance(inches) 29 in
44 Depth of forebay at exit(inches) 36 in
45 Does water flow out of the forebay in a non-erosive manner? Yes
46 Width of the vegetated shelf(feet) 6 ft
47 Slope of vegetated shelf(H:V) 6:1
48 Does the orifice drawdown from below the top surface of the Yes
permanent pool?
Does the pond minimize impacts to the receiving channel from the 1-
49 Yes
yr,24-hr storm?
50 Are fountains proposed?(If Y.please provide documentation that No
MDC(9)is met.)
51 Is a trash rack or other device provided to protect the outlet system? Yes
52 Are the dam and embankment planted in non-clumping turf grass? Yes
53 Species of turf that will be used on the dam and embankment
54 Has a planting plan been provided for the vegetated shelf? Yes
ADDITIONAL INFORMATION
55 Please use this space to provide any additional information about the
wet pond(s):
Wet Pond 1 1:33 PM 11/6/2023