SW6241008_Supplement-EZ Form_20241112

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name
Kirwin Village
2 Project Area(ac) 46.24
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? No
COMPLIANCE WITH 02H .1003(4)
7 Width of vegetated setbacks provided(feet) 30
8 Will the vegetated setback remain vegetated? N/A
9 If BUA is proposed in the setback,does it meet NCAC 02H.1003(4)(c-d)? No
10 'Is streambank stabilization proposed on this project? No
NUMBER AND TYPE OF SCMs:
_11 Infiltration System
12 Bioretention Cell
13 Wet Pond 1
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(DIS)
21 ;Treatment Swale
22 Dry Pond
23 StormFilter
24 ',Silva Cell
25 Bayfilter
26 jFilterra
FORMS LOADED
DESIGNER CERTIFICATION _w
27 Name and Title: Matt Lowder, PE
28 Organization: Bowman North Carolina,Ltd.
29 •Street address: 4006 Barrett Drive,Suite 104
30 City,State,Zip: Raleigh,NC 27609
31 Phone number(s): [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.
Designer
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DRAINAGE AREAS
Q Is this a high density project? Yes
EN If so,number of drainage areas/SCMs 1
®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 I
4 Type of SCM Wet Pond
5 Total drainage area(sq ft) 2014364 522070
6 Onsite drainage area(sq ft) 2014364 522070
7 Offsite drainage area(sq ft)
8 Total' BUA in project(sq ft) 627686 sf 254536 sf
!New BUA on subdivided lots(subject to permitting)
9 (sq ft) 452000 sf 188000 sf
New BUA not on subdivided lots(subject to
10 permitting)(sf) 175686 sf 66536 sf
11 Offsite BUA(sq ft)
12 Breakdown of new BUA not on subdivided lots: __
-Parking(sq ft)_
-Sidewalk(sq ft) 46753 sf 17828 sf
-Roof(sq ft) _
-Roadway(sq ft) 128933 sf 48708 sf
-Future(sq ft)
-Other,please specify in the comment box
below(sq ft)
New infiltrating permeable pavement on
13 ,subdivided lots(sq ft)
New infiltrating permeable pavement not on
14 subdivided lots(sq ft)
Existing BUA that will remain(not subject to
15 permitting)(sq ft)
` 16 Existing BUA that is already permitted(sq ft) 373150 sf
17 Existing BUA that will be removed(sq ft)
18 Percent BUA 31% 49%
19 Design storm(inches) 1.0 in
20 Design volume of SCM(cu ft) _ 31618 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):
The existing BUA that is already permitted is covered under SW6220504.

WET POND
1 Drainage area number 1
2 Minimum required treatment volume(cu ft) 1 21265 cf
GENERAL MDC FROM 02H.1050
3 Is the SCM sized to treat the SW from all surfaces at build-out? Yes
4 i Is the SCM located away from contaminated soils? Yes
51 What are the side slopes of the SCM(H:V)? 3:1
6!side Does
the
SCM have retaining walls,gabion walls or other engineered No
7 Are the inlets,outlets,and receiving stream protected from erosion Yes
(10-year storm)?
g,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)?
14i 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 designed by an NC licensed professional? 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 261.00
removal)(fmsl)
21 Elevation of the main pool bottom(top of sediment removal)(fmsl) 262.00
22 Elevation of the bottom of the vegetated shelf(fmsl) 266.50
23 Elevation of the permanent pool(fmsl) 267.00
24 Elevation of the top of the vegetated shelf(fmsl) 267.50
25 Elevation of the temporary pool(fmsl) 268.60 _
26 Surface area of the main permanent pool(square feet) 11840
—
27 Volume of the main permanent pool(cubic feet) 50113 cf _
28 Average depth of the main pool(feet) 4.20 ft
293Average depth equation used Equation 3 —
30 If using equation 3,main pool perimeter(feet) 504.0 ft
31 If using equation 3,width of submerged veg.shelf(feet) 3.0 ft
32;Volume of the forebay(cubic feet) 8568 cf
3311s this 15-20%of the volume in the main pool? _ Yes
341Clean-out depth for forebay(inches) 36 in
31618 cf 35i`Design volume of SCM(Cu ft) _
36'Is the outlet an orifice or a weir? Orifice
37 If orifice,orifice diameter(inches) 2 in
38 If weir,weir height(inches)39 If weir,weir length(inches)
40 Drawdown time for the temporary pool(days) 3.83
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) 36 in
44 Depth of forebay at exit(inches) 24 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
Does the orifice drawdown from below the top surface of the
48lpermanent pool? Yes
49:Does the pond minimize impacts to the receiving channel from the 1- 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 Hybrid Bermuda
54'Has a planting plan been provided for the vegetated shelf? Yes
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
5 wet pond(s):
Wet Pond 1 8:53 AM 10/22/2024