SW5240202_Supplement-EZ Form_20241004

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name J WRENN VILLAS, —
2 Pry eet AreaJac) �It _ 33.31
3 Coastal Welland Area ac 0
4 Surface Water Area ac _ 0.50 _
5 Is this projert H h or Low Density? Both Fligtt.and Low Density
a Does this project use an off-site SCM? Yes
COMPLIANCE WITH 02H.1003(4)
7 WW[h of elated setbacks nrnAdpd freell 50 _
8 WUI the❑ emled setback remain vegetated? T Yes —
9 'If BUA is proppqed In the setback.does it meet NCAC 021-1.1003 4 ad? _ N/A
10 Is streambank stabilization proposed on this project? No
NUMBER AND TYPE OF SCMs:
11 .Inflilration Yatem
12 Bioretentlon Cell _
13 ,'Wet Pond 1 _ T-
14 75trrnwater Wetland --._-
15 Permeable Pavement
16 Sand Filter —
17 Rainwater Hamesiirttt IRWH t_.
18 Green Roof
19 1 Levei Spmadar+11ter Std LS-FS
20 Dfscannected ImpervIous Surface IS
21 ITrmstment Swale > >
22 lDrvPond
23 Storm Filter
24 Sllva Cell
25 �Ba d3er --- — _--
26 Filterra
FORMS LOADED
DESIGNER CERTIFICATION
27 INEirne and Title: _John R Wadswarthj_PE-erect Engineer
28 I nizaflon: Timmons Group _
5410 Trinity Road;StP 102
29 IStreetadtlress: i _ —
30 EI Stale Zip:
Ralef h NC 27607
31 Phone numbers' 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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DRAINAGE AREAS
1 1 Is this a high densq project? Yes
2 If so number of drainage areas/SCMs 1
3 Does this project have low density areas? Yes
4 If so,number of low density drainage areas 1
Is all/part of this project subject to previous rule
5 versions? No
t}RM LOADED
DRAINAGE AREA INFORMATION Entire Site 1 LD 1
4 1 Type of SCM Wet Pond
5 Total drainage area(so ft) 2,541,423 887.556 144993
6 ]Onsite drainaae area(sq ft) 1003684 887556 116128
7 loffsite drainage area(sq ft) 1051512 0 28864
8 Total BUA in project(sq ft) 568749 sf 528583 sf 40166 sf
New BUA on subdivided lots(subject to permitting)
9 (so ft) 366950 sf 366950 sf sf
New BUA not on subdivided lots(subject to
10 permittinc.0(sf) 181583 sf 161633 sf 19950 sf
11 Offsite BUA(sq ft) 738231 sf 8602 sf
12 Breakdown of new BUA not on subdivided lots:
Parkin (sq ft) 17000 sf 17000 sf
Sidewalk(sq ft 48440 sf 39090 sf 9350 sf
Roof(sq ft
Roadway s ft 116143 sf. 105543 sf _ 10600 sf
Future(sq ft
Other,please specify in the comment box
below(sq ft
New infiltrating permeable pavement on
13 subdivided lots(sq ft) N/A N/A N/A
New infiltrating permeable pavement not on
14 i subdivided lots(sq ft) N/A N/A N/A
Existing BUA that will remain(not subject to
15 Dermittin(i)(sq ft) 11614 sf N/A 11614 sf _
16 JEAsting BUA that is already permitted(sq ft) N/A N/A N/A
17 Existing BUA that will be removed(sq ft) N/A N/A N/A
18 Percent BUA 57% 60% 14%
19 Design storm(inches) 1.0 in N/A
20 Design volume of SCM(cu ft) 76372 cf N/A
21 Calculation method for design volume Simple Method N/A
ADDITIONAL INFORMATION
+Please use this space to provide any additional information about the
22 drainage area(s):
All the offsite BUA is bypassing the SCM.Drainage area 1 drains to the SCM.
Drainage area LD1 drains to POI 2.A small portion of this project,29,185 sf
(considered 100%BUA),drains to an offsite in Wrenn Farms to the east.

OFF-SITE SCM
THE DRAINAGE AREA
1 Drainage area number for this project 1
2 Master permit number 5240201
3 Drainage area number from the master permit 1
4 Lot or outparcel number I Wrenn Farms
5 BUA allocated by Master Permit 29185 sf
INFORMATION ABOUT THE OFF-SITE SCM
6 Type of off-site SCM Wet Pond
7 Available treatment capacity in the off-site SCM (cu ft) 260192 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? Yes
12 Will the collections stem be maintained in its design state and kept clean? Yes
ADDITIONAL INFORMATION
13 1 Please use this space to provide any additional information about the off-site SCM(s):

WET POND
1 D41nage area number f
2'Minimum required Veatmerri volume w A 49343 d
3
31Is the SCM shed to veal the SW from all surfaces at bind-out? Yes
4 Is the SCM located away from contaminated soils? Yes
5 What are the side slopes of the SCM H:V 7 1 3:1
QoeS the SCM have retaining walls,gabion walls or other engineered No
7 Are the inlets,outlets,and receiving stream protected from erosion Yes
f10-year storm)?
Is there an overflow or bypass for inflow volume in excess of the Yes
8 design volume?
9 What is the method for dewatering the SCM for maintenance? Rump foreferred)
10 IF aDDlicable,will the SCM be cleaned out after construction? as _
11_Does the maintenance access comDly with General MDC(e)? Yes
12 Does the drainaqe easement comply with General MDC(9)7 Yes
13 If the SCM is on a single family lot,does(will?)the plat comply with NIA
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 soecfic MDC? Yes
17 1 Was the SCM designed on NC licensed esslonar7 I Yes
WET POND MDC FRDM GZH.14S3
18 SWng method used SWDA
19 Hasa stage/storage table been Drovided in the calculations? Yes
20 Elevation of the excavated main pool depth(bottom of sediment 404.50
removal)ffmsl.)
21 Elevation of the main pool bottom(top of sediment removal)(fmsl) 405.50
22 Elevation of the bottom of the vegetated shelf(fmsl) 410-00
23 Elevation of the permanent pool(fmsl) 410.00
24 Elevation of the too of the vegetated shelf(fmsl) 411.00
25 Elevation of the temograrV Dool(fmsl) 415.00
26 Surface area of the main permanent pool(square feet) 17398
27 Volume of the main permanent pool cubic feet T 61058 cf
28 Avera a depth of the main pool feet 3.50 ft
29 Ave ra a depth e uation used E uadon 3
30 If using a uation 3 mainRoo[perimeter feet 596.0 ft
31 If using equation 3,width of submerged veg.shelf(feet) _
32 Volume of the forebav(cubic feet) 9631 cf
33 Is this 15-20%of the volume in the main pool? Yes
34 Clean-out depth for forebay(inches) 48 in
35 Design volume of SCM(cu ft) 76372 cf
36 Is the outlet an orifice or a weir? Orifice
37 If orifice,orifice diameter(inches) 2,75 in
38 If weir,we height(inches)
39 If weir.weir lenath(inches)
401Drawdowm time for the temoorary pool(days) 3.2
41 Are the inlet(s)and outlet located in a manner that avoids short- Yes
rvcuitinn? _
42 pre berms or baffles provided to improve the flow path? No
43 De th of forebav at entrance(inches) 60 in
44 depth.Df forebav at exit(inches 48 in
45 Does water flow out of the forebay in a non-erosive manner? (� Yes
48 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 No
erman_ent pool?
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 T
MDC(g)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 S ecies of turf that will be used on the dam and embankment Bermuda _
54 Hoc a planting plan been Drovided for the vegetated shelf? Yes
ADDMOHAL INFORMATION
Please use this space to provide any additional information about the
55,Net pond(s):
2

LOW DENSITY_
DESIGN REQUIREMENTS FOR LOW DENSITY PROJECTS FROM 02H.1003
1 1 Is project below density thresholds set forth in the applicable stormwater rule? 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) 3:1
5 Maximum velocity in the vegetated conveyances during the 10-year storm? 3.1
6 Are curb outlet swales proposed? No
7 Maximum lonqitudinal 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?
712711.stormwater released at the edge of the setback as dispersed flow? Yes
13 1 Have stormwater outlets been designed to prevent downs lope 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 a roadside swale and RCP pipes.Runoff will outlet at non-erosive velocities.
Calculcations pipes are provided in the stormwater impact analysis.
Drainage Pervious
Swale BUA Q Slope V,ii,,,, V,_, Flow depth
# (a (ac) fact a area C Mir) N (fps) (fps) (ft)
1
2 -
3
4 0.63 0.63 0-95 4.32 1.40 5.00 2.45 0.78
5 1.09 1.09 _ 0.95 7.48 3.10 fIf 5.00 3.10 0.82
6 V
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11 I
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15 I
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29 r
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