SW6240603_Supplement-EZ Form_20240617

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name West Pointe Subdivision
2 Project Area(ac) 59.31
3 Coastal Wetland Area(ac) 0
4 Surface Water Area(ac) 0 _
5 Is this project High or Low Density? _ Low _
6 Does this project use an off-site SCM? Yes
COMPLIANCE WITH 02H.1003(4)
7 Width of vegetated setbacks provided(feet) N/A
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)? N/A
10 Is streambank stabilization proposed on this project? No
NUMBER AND TYPE OF SCMs:
11 Infiltration System 0 _
12 Bioretention Cell 1 0
13 Wet Pond 1 0
14 Stormwater Wetland 0 —
15 I Permeable Pavement 0
16 Sand Filter 0
17 JRainwater Harvesting(RWH) 0
18 Green Roof 0
19 1Level Spreader-Filter Strip(LS-FS) 0
20 Disconnected Impervious Surface(DIS) 0 __ _
21 Treatment Swale 0
22 Dry Pond _ 1
23 StormFilter 0
24 Silva Cell 0 _ _
25 Bayfilter 0
26 Filterra I 0
FORMS LOADED
DESIGNER CERTIFICATION
27 Name and Title: Ryan Wadsworth,PE _
28 Organization: Timmons Group
29 Street address: 5410 Trinity Rd,Suite 102
30 City,State,Zip: Raleigh.NC 27607
31 Phone number(s): _ 919-866-4516
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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OFF-SITE SCM
THE DRAINAGE AREA
1 Drainage area number for this project LD 8
2 Master permit number SW6100804
3 Drainage area number from the master permit LD 8
4 Lot or outparcel number Subdivision
5 BUA allocated by Master Permit 85658 sf
INFORMATION ABOUT THE OFF-SITE SCM
6 Type of off-site SCM I Wet Pond
7 Available treatment capacity in the off-site SCM (cu ft) 67707 cf
8 Have deed restrictions limiting the BUA on the site been recorded? No
9 Has an Engineer's Certification for the off-site SCM been submitted to DEQ? No
10 Are there any Notices of Violation for the off-site system? No
11 Has the off-site SCM been maintained in accordance with its O&M Plan? No
12 Will the collection system be maintained in its design state and kept clean? Yes
ADDITIONAL INFORMATION
13 Please use this space to provide any additional information about the off-site SCM(s):
The residential portion of the drainage area to the SCM permitted with SW6100804 and SW6220603 has not
been constructed as of the date of this submission.

LOW DENSITY
QESJGN REQUIREMENTS FOR LOW DENSITY PROJECTS FROM 02H.1003
1 I Is project below density thresholds set forth in the applicable stormwater rule? I Yes
2 Does project maximize dispersed flow and minimize channelization of flow? Yes
3 Has the use of piping been minimized per.1003(2)(c)? Yes
4 Side slopes of the vegetated conveyances(H:V) 2:1
5 Maximum velocity in the vegetated conveyances during the 10-year storm? 8.3
6 i Are curb outlet swales proposed? No
7 Maximum longitudinal slope of curb outlet swale(s)(%)
8 Bottom width of curb outlet swale(s)(feet)
9 Maximum side slope of curb outlet swale(s)(H:V)
10 Minimum length of curb outlet swale(s)(feet)
11 Are treatment swales used instead of curb outlet swales?
12 Is stormwater released at the edge of the setback as dispersed flow? 1 N/A
13 Have stormwater outlets been designed to prevent downslope erosion? Yes
14 Are variations to rule.1003 proposed? No
ADDITIONAL INFORMATION
15 Please use this space to provide any additional information about this low density project:
Stormwater runoff will be conveyed with the use of roadside swales and RCP culverts and outlet at non-erosive velocities.
Calculcations for swales and culverts are provided in the stormwater impact analysis.
Drainage Pervious
Swale BUA Q `` Slope V,i„, V,,„„i Flow depth
# ace) (oc) area fact (cfs) (%) Its) (fPs) (ft)
1
2
3
4
5
6
8
9
10
11
12
13
14
15
16
17
18
19 t —
20
21
22
23
24
25
28
27 - -
28
29
30

DRY POND
1 Drainage area number 3
2 Minimum required treatment volume(cu ft) I 26287 cf
GENERAL MDC FROM 02H.1050
31Is the SCM sized to treat the SW from all surfaces at build-out? I Yes
4j 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? 1 __
7 Are the inlets,outlets,and receiving stream protected from erosion(10. Yes
year storm)?
8 Is there an overflow or bypass for inflow volume in excess of the Yes
desgn volume?
9 What is the method for dewatering the SCM for maintenance? Drawdown Orifice
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 Yes
General MDC(10)?
14 Is there an O&M Agreement that complies with General MDC(11)? Yes
— 1 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
DRY POND MDC FROM 02H.1062
18 SHWT elevation(fmsl)
19 Elevation of the bottom of the dry pond(fmsl) I 414
20 Distance from bottom to SHWT(feet)
21 Elevation of the temporary pool during the design storm(feet) I 417.20 ft
22 Ponding depth of the design storm(feet) 1 417.20 ft
23 Will the dry pond be uniformlygraded to flow toward the outlet? Yes
24 Is a low flow channel being provided? No
25 Are the inlet(s)and outlet located in a manner that avoids short- Yes
circuiting?
26 Will berms or baffles be provided to increase the flow path? No
27 What method of pretreatment will be provided? Dissipation pad
28 Design volume of SCM(cu ft) 26287 _
29J Diameter of drawdown orifice(in) 2.0 in
30j Drawdown time for the temporary pool(hours) 69.6 _
31 Does the pond minimize impacts to the receiving channel from the 1- Yes
yr,24-hr storm?
32 Is there a small permanent pool near the orifice to prevent clogging? Yes
33 Will the outlet be designed to prevent cloggin ? I Yes
34 Are the dam and embankment planted in non-clumping turf grass? Yes
35 Species of turf that will be used on the dam and embankment Bermuda
36 Will trees and shrubs be prevented from growing on the dam and I Yes
embankment? i
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
37 dry pond(s)_ -_
Dry pond is provided to help reduce flows and control velocity of swales
leaving the site to southeast.
Dry Pond 5 11:07 AM 5/17/2024