SW6231002_Supplement-EZ Form_20231031

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name Serenity-Phases 8&9
2 Project Area(ac) 170.33
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 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
12 ,Bioretention Cell
13,Wet Pond I 6
14 Stormwater Wetland T
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 2
22 Dry Pond
23 StormFilter
24 Silva Cell
25 Bayfilter
26 Filterra
FORMS LOADED
DESIGNER CERTIFICATION
27 Name and Title: Brandon Miller,PE-Project Manager
28 Organization: I WithersRavenel,Inc.
29 Street address: ( 115 MacKenan Drive
30 City,State,Zip: Cary,NC 27511
31 Phone number(s): 919.469.3340
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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Seal Date
11:04 AM10/12/2023

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Serenity-Phases 8 9
WET POND
1 jDrainage area number I SCM 6 SCM 7 SCM 8 SCM 9 SCM 10 SCM 11 i
2iMinimum required treatment volume(cu ft) I 22796 cf } 45253 cf , 15883 cf ( 31156 cf ' 35572 cf 22061 22061 of
§ENERAL MDC FROM 02H.1050 T -
3;Is the SCM sized to treat the SW from all surfaces at build-out? _ Yes _ Yes Yes Yes Yes Yes
4 Is the SCM located away from contaminated soils? Yes Yes Yes Yes Yes Yes
5 What are the side slopes of the SCM(H:V)? 3:1 3:1 3:1 3:1 3:1 3:1
6 Does the SCM have retaining walls,gabion walls or other engineered No No No No No No
side slopes?
7 Are the inlets,outlets,and receiving stream protected from erosion I Yes Yes Yes Yes Yes Yes
(10-year storm)?
8 Is there an overflow or bypass for inflow volume in excess of the Yes Yes Yes Yes Yes Yes
design volume?
9 What is the method for dewatering the SCM for maintenance? Drawdown Orifice Drawdown Orifice Drawdown Orifice Drawdown Orifice Drawdown Orifice Drawdown Orifice
10 If applicable,will the SCM be cleaned out after construction? Yes Yes Yes Yes Yes Yes
11 Does the maintenance access comply with General MDC(8)? Yes Yes Yes Yes Yes Yes
12 Does the drainage easement comply with General MDC(9)? Yes Yes Yes Yes Yes Yes
13 If the SCM is on a single family lot,does(will?)the plat comply with N/A N/A N/A N/A N/A N/A
General MDC(10)?
-
14 Is there an O&M Agreement that complies with General MDC(11)? Yes Yes Yes Yes Yes Yes
151Is there an O&M Plan that complies with General MDC(12)? Yes Yes Yes Yes Yes Yes
16;Does the SCM follow the device specific MDC? Yes Yes Yes Yes Yes Yes
17IWas the SCM designed by an NC licensed professional? Yes Yes Yes Yes Yes Yes
1NET POND MDC FROM Man -
I 18ISizing method used SA/DA SA/DA SA/DA SA/DA SA/DA SA/DA
1 19 Has a stage/storage table been provided in the calculations? f Yes Yes Yes Yes Yes Yes
20 Elevation of the excavated main pool depth(bottom of sediment
removal)(fmsl)
21 Elevation of the main pool bottom(top of sediment removal)(fmsl)
22 Elevation of the bottom of the vegetated shelf(fmsl) 327.00 _ 328.00 352.00 362.00 370.00 376.00
23 Elevation of the permanent pool(fmsl) 327.50 _ 328.50 352.50 362.50 370.50 376.50
24 Elevation of the top of the vegetated shelf(fmsl) 328.00 329.00 353.00 363.00 371.00 377.00
25 Elevation of the temporary pool(fmsl) 330.00 331.25 355.00 364.25 372.25 378.50
26 Surface area of the main permanent pool(square feet) _ 8515 21078 10655 14664 18135 9676
27 Volume of the main permanent pool(cubic feet)
28 Average depth of the main pool(feet) 4.00 ft 3.00 ft 3.00 ft 3.00 ft 3.00 ft 3.00 ft
29 Average depth equation used Equation 3 Equation 3 Equation 3 Equation 3 Equation 3 Equation 3
30 If using equation 3,main pool perimeter(feet) 413.0 ft _ 669.0 ft 413.0 ft 520.0 ft 600.0 ft 495.0 ft
31 If using equation 3,width of submerged veg.shelf(feet) _ 3.0 ft 3.0 ft 3.0 ft 3.0 ft 3.0 ft 3.0 ft
32 Volume of the forebay(cubic feet)
33 Is this 15-20%of the volume in the main pool? Yes Yes Yes Yes Yes Yes
34 Clean-out depth for forebay(inches) 12 in 12 In 12 in 12 in 12 in 12 in
35 Design volume of SCM(cu ft) 34767 cf 85034 cf 40529 cf 36545 cf 44087 cf 28803 cf
36 Is the outlet an orifice or a weir? Orifice Orifice Orifice Orifice Orifice Orifice
37 If orifice,orifice diameter(inches) 2.50 in 3.50 in 2.25 in 3.00 in 3.25 in 2.50 in
38 If weir,weir height(inches) `
39 If weir,weir length(inches)
40 Drawdown time for the temporary pool(days) 2.167 2.292 2.375 2.167 2.167 2.167
41 Are the inlet(s)and outlet located in a manner that avoids short- Yes Yes Yes Yes Yes Yes
circuiting?
42 Are berms or baffles provided to improve the flow path? No No No No No No
43 Depth of forebay at entrance(inches)
44 Depth of forebay at exit(inches)
45 Does water flow out of the forebay in a non-erosive manner? Yes Yes Yes Yes Yes Yes
46 Width of the vegetated shelf(feet) Eft Eft Eft Eft Eft 6 ft
47 Slope of vegetated shelf(H:V) 6:1 6:1 6:1 6:1 6:1 6:1
48 Does the orifice drawdown from below the top surface of the Yes Yes Yes Yes Yes Yes
permanent pool? _
49 Does the pond minimize impacts to the receiving channel from the 1- Yes YesYes Yes Yes Yes
yr,24-hr storm?
50 Are fountains proposed?(If Y,please provide documentation that No No No No No No
MDC(9)is met.)
51 Is a trash rack or other device provided to protect the outlet system? Yes Yes Yes Yes Yes Yes
52 Are the dam and embankment planted in non-clumping turf grass? Yes Yes Yes Yes yes Yes
53 Species of turf that will be used on the dam and embankment Centipede Centipede Centipede Centipede Centipede Centipede
54 Has a planting plan been provided for the vegetated shelf? Yes Yes Yes Yes Yes Yes
ADDITIONAL INFORMATION
55 Please use this space to provide any additional information about the
wet pond(s):
2

Serenity-Phases 8 9
TREATMENT SWALE
1 Drainage area number I SCM 12 SCM 13
2 Design flow rate of SCM_ (cfs) .89 cfs .90 cfs
GENERAL MDC FROM 02H.1050__ _
31ls the SCM sized to treat the SW from all surfaces at build-out? Yes Yes
4jls the SCM located away from contaminated soils? No No
5 What are the side slopes of the SCM(H:V)? 3:1 3:1
1 Does the SCM have retaining walls,gabion walls or other
6 engineered side slopes? No No
7 Are the inlets,outlets,and receiving stream protected from erosion Yes Yes
(10-year storm)?
Is there an overflow or bypass for inflow volume in excess of the
8 design volume? No No
9 What is the method for dewatering the SCM for maintenance? Other Other
10 If applicable,will the SCM be cleaned out after construction? N/A N/A
11,Does the maintenance access comply with General MDC(B)? Yes Yes
121Does 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 I N/A N/A
General MDC(10)?
14jls there an O&M Agreement that complies with General MDC(11)? Yes Yes
1511s 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 desi.ned by an NC licensed professional? ! Yes Yes
r. t' _ ''!1
.�1 _z
W 1B1SHT elevation(fmsl)
19 Bottom of the treatment swale(fmsl) 377.25 312.50
20 Depth of treatment swale(feet) 1.5 1.5
21 Is the swale trapezoidal in shape? Yes Yes
22 Width of bottom of swale(feet) 6 ft 6 ft
23 Side slopes of treatment swale(H:V) j 3:1 3:1
24 Length of swale(feet) 100 ft 100 ft
25 Flow depth during the 0.75 inch/hour storm(inches) 3 in 1.32 in
26 Flow velocity during the 0.75 inch/hour storm(feet per second) i 0.71 1.34
27 Hydraulic retention time for swale(minutes) 7 min 7 min
28 Species of grass that will be used Bermuda Bermuda
29 Will the grass be maintained at an average height of 6 inches? Yes Yes
30 Will the grass not be cut lower than 4 inches? Yes Yes
31 Velocity during the 10-year storm(feet per second) j 3 ft/s 3 ft/s
32 Is the swale designed to non-erosively pass the 10-year storm? Yes Yes
ADDITIONAL INFORMATION
33 Please use this space to provide any additional information about the
treatment swale(s):
•