SW6080602_Supplement-EZ Form_20240730

SUPPLEMENT-EZ COVER PAGE
FORM$LQADEr
PROJECT INFORMATION
1 Project Name Project Gain Larkspur
2 Project Area(ac) 8
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) 0
8 Will the vegetated setback remain vegetated? N/A
9 II 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
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-Fitter Strip(LS-FS)
20 Disconnected Impervious Surface(DIS) _
21 Treatment Swale _
22 Dry Pond
23 StormFilter
24 Silva Cell _
25 Bayfitter
26 Filterra
FORMS LOADED
DESIGNER CERTIFICATION
27 Name and Title: William Akin,PE
28 Organization: _ Civil Consultants,Inc
29 Street address: 3708 Lyckan Parkway,Suite 201
30 City,State,Zip: Durham,NC 27707
31 Phone number(s): 919-490-1645
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.
t7eslpner 00111 n7 frll�.rr,
SEp�l_ i = Signature of Designer
045959 j s
''„,„/Aaili ll"►�t,_ `,, 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
o r, EHAC,tu
DRAINAGE AREA INFORMATION Entire Site 1 2
4 Type of SCM Wet Pond Wet Pond
5 Total drainage area(sq ft) _ 159817 ~-175893
6 Onsite drainage area(sq ft) _ _ _ 159817 175893
7 Offsite drainage area(sq ft) _ - 0 0
8 Total BUA in project(sq ft) 127313 sf 110643 sf_
New BUA on subdivided lots(subject to
9 permitting)(sq ft) sf sf
New BUA not on subdivided lots(subject to
10 permitting)(sf) 127313 sf 110643 sf
11 Offsite BUA(sq ft) sf sf
12 Breakdown of new BUA not on subdivided lots:
-Parking(sq ft) 82854 sf 49958 sf
-Sidewalk(sq ft) 4459 sf 1081 sf
-Roof(sq ft) 59604 sf
-Roadway lsq ft)
—7-Future(sq ft)
-Other,please specify in the comment box
below(sq ft)
New infiltrating permeable pavement on
13 subdivided lots(sq ft) sf sf
New infiltrating permeable pavement not on
14 subdivided lots(sq ft) sf sf
Existing BUA that will remain(not subject to
15 permitting)(sq ft) sf sf
16 Existing BUA that is already permitted(sq ft) sf sf
17 Existing BUA that will be removed(sq ft) sf sf
18 Percent BUA 80% 63%
19 Design storm(inches) 1.0 in 1.0 in
20 Design volume of SCM(cu ft) 10214 cf 9031 cf
21 Calculation method for design volume SA/DA SA/DA
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 drainage area(s):

WET POND
Drainage area number I 1 I 2
2 Minimum required treatment volume(cu ft) 10214 d 9031 cf
GENERAL 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 sods? Yes Yes
5 What are the side slopes of the SCM(H:V)? _ 3:1 3:1
6 Does the SCM have retaining walls,gabion walls or other No No
engineered side slopes?
7 Are the inlets,outlets,and receiving stream protected from erosion Yes Yes
(10-year storm)?
8 Is there an overflow or bypass for inflow volume in excess of the Yes Yes
design volume?
9 What is the method for dewatering the SCM for maintenance? Pump(preferred) 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
17 Was the SCM designed px an NC licensed professional? Yes Yes
WET POND MDC FROM 02H.1053
18 Sizing method used SA/DA SA/DA
19lHas a stage/storage table been provided in the calculations? Yes Yes
Elevation of the excavated main pool depth(bottom of sediment20 181 78 182.00
removal)(fmsl)
21 Elevation of the main pool bottom(top of sediment removal)(fmsl) 182.78 183.00
22 Elevation of the bottom of the vegetated shelf(fmsl) 185.28 186.00
23 Elevation of the permanent pool(fmsl) 185.58 186.31
24 Elevation of the top of the vegetated shell(frnsl) 185.88 186.61
25 Elevation of the temporary pool(fmsl) 189.78 187.75
26 Surface area of the main permanent pool(square feet) 4990 6200
27 Volume of the main permanent pool(cubic feet) 13441 d 17613 cf
281Average depth of the main pool(feet) 3.50 ft 2.84 ft
29 Average depth equation used Equation 2 Equation 2
30 If using equation 3,main pool perimeter(feet)
31 If using equation 3,width of submerged veg.shelf(feet)
32 Volume of the forebay(cubic feet) 2494 d 3115 d
33 Is this 15-20%of the volume in the main pool? Yes Yes
34 Clean-out depth for forebay(inches) 12 in 12 in
35 Design volume of SCM(cu ft) 31086 d 17896 d
36 Is the outlet an orifice or a weir? Orifice Orifice
37 If orifice,orifice diameter(inches) 1 in 1 in
38 If weir.weir height(inches)
39 If weir.weir length(inches)
40 Drawdown time for the temporary pool(days) 2.88 2.22
41 Are the inlet(s)and outlet located in a manner that avoids short- Yes Yes
circuiting?
42 Are berms or baffles provided to improve the flow path? Yes Yes
43 Depth of forebay at entrance(inches) 48 in 48 in
44 Depth of forebay at exit(inches) 48 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) 6 ft 6 ft
47 Slope of vegetated shell(H:V) 10:1 10:1
a6 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 I. Yes Yes
yr,24-hr storm?
50 Are fountains proposed?(If Y,please provide documentation that No No
MOC(9)is met.)
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 darn and embankment
54 Has a planting plan been provided for the vegetated shelf? Yes Yes
ADDITIONAL INFORMATION
Please use this space to provide any additional information about
55 the wet pond(s):
Wet Pond 1 Drains drainage area B:Wetpond 2 draings drainage area A
Wet Pond 1 3 8:40 AM 6/11/2024