SW4240401_Supplement-EZ Form_20240801

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name Whitehall Village South
2 Project Area(ac) 6.874
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? Yes
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 2
13 Wet Pond 0
14 Stormwater Wetland 0
15 Permeable Pavement 0
16 Sand Filter 0
17 Rainwater Harvesting(RWH) 0
18 Green Roof 0
19 Level Spreader-Filter Strip(LS-FS) 0
20 Disconnected Impervious Surface pis) 0
21 Treatment Swale 0
22 Dry Pond 0
23 Storm Filter 0
24 Silva Cell 0
25 Bayfilter 0
26 Filterra 0
FORMS LOADED
DESIGNER CERTIFICATION
27 Name and Title: Charles P.Truby,Jr.PE PLS President
28 Organization: CPT Engineering and Surveying,Inc.
29 Street address: 4400 Tyning Street
30 City,State,Zip: High Point,NC,27265
31 Phone number(s): [phone] x 304
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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BIORETENTION CELL
1 Drainage area number 1 2
2 Minimum required treatment volume cu ft) 3341 cf 8506 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 soils? Yes Yes
5 What are the side slopes of the SCM(H:V)? 3:1 1:1
6 Does the SCM have retaining walls,gabion walls or other engineered
side slopes? Yes Yes
7 Are the inlets, outlets,and receiving stream protected from erosion
(10-year storm)? Yes Yes
8 Is there an overflow or bypass for inflow volume in excess of the
design volume? Yes Yes
9 What is the method for dewatering the SCM for maintenance? Drawdown Orifice Drawdown Orifice
_ 10 If applicable,will the SCM be cleaned out after construction? Yes Yes
11 Does the maintenance access comply with General MDC(8)? Yes No
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
General MDC(10)? N/A N/A
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 by an NC licensed professional? Yes Yes
BIORETENTION CELL MDC FROM 02H.1052
18 SHWT elevation(fmsl) 973.50 957.00
19 Bottom of the bioretention cell(fmsl) 976.72 968.70
20 Ponding depth of the design storm(inches) 12 in 12 in
21 Surface area of the bioretention cell(square feet) 3459 sf 8534 sf
22 Design volume of SCM(cu ft) 3341 cf 8506 cf
23 Is the bioretention cell used for peak attenuation? Yes Yes
24 Depth of peak attenuation over planting surface(in) 24 in 24 in
25 Height of peak attenuation outlet above the planting surface(in) 18 in 18 in
26 Infiltration rate of the in situ soil(inch/hour) NA NA
27 Diameter of the underdrain pipes(if applicable) 6 in 6 in
28 Does the design include Internal Water Storage(IWS)? Yes Yes
29 if so, elevation of the top of the IWS(fmsl) 979.5 971.5
30 Elevation of the planting surface(fmsl) 981 973
31 What type of vegetation will be planted? (grass,trees/shrubs, other)? Grass Grass
32 Media depth(inches) 30 in 30 in
33 Percentage of medium to coarse washed sand by volume 75-85% 75-85%
34 Percentage of fines(silt and clay)by volume 8-15% 8-15%
35 Percentage of organic matter by volume 5-15% 5-15%
36 Type of organic material Pine Bark Pine Bark
37 Phosphorus Index(P-Index)of media(unitless) 50 50
38 Will compaction be avoided during construction? Yes Yes
39 Will cell be maintained to a one inch/hour standard? Yes Yes
40 Depth of mulch,if applicable(inches) in in
41 Type of mulch, if applicable 0 0
42 How many clean out pipes are being installed? 5 10
43 Type of pretreatment that will be used: Rip-rap Forebay Rip-rap Forebay
ADDITIONAL INFORMATION
44 Please use this space to provide any additional information about the
bioretention cell(s):
Proposed Bio-Cell#2 will require impermeable geo-membrane liner to top of
sod(973.0)
�3ioretention — '- _. 1 1:30 PM 7/31/2024

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
FORMS LOADED
DRAINAGE AREA INFORMATION Entire Site 1 2
4 Type of SCM Bio-cell Bio-cell Bio-cell
5 Total drainage area (sq ft) 243936 67953.6 175982.4
6 Onsite drainage area (sq ft) 243936 67953.6 175982.4
7 Offsite drainage area (sq ft) 0 0 0
8 Total BUA in project(sq ft) 144184 sf 40511 sf 103673 sf
New BUA on subdivided lots (subject to permitting)
9 (sq ft) sf sf sf
New BUA not on subdivided lots(subject to
10 permitting)(sf) sf sf sf
11 Offsite BUA(sq ft) sf sf sf
12 Breakdown of new BUA not on subdivided lots:
- Parking (sq ft) 470 sf 470 sf sf
-Sidewalk(sq ft) 7805 sf 1704 sf 6101 sf
- Roof(sq ft) 83933 sf 23777 sf 60156 sf
- Roadway(sq ft) 35685 sf 9749 sf 25936 sf
- Future(sq ft) sf sf sf
-Other, please specify in the comment box below
(sq ft) sf sf sf
New infiltrating permeable pavement on subdivided
13 lots(sq ft) sf sf sf
New infiltrating permeable pavement not on
14 subdivided lots (sq ft) sf sf sf
Existing BUA that will remain (not subject to
15 permitting)(sq ft) sf sf sf
16 Existing BUA that is already permitted (sq ft) sf sf sf
17 Existing BUA that will be removed (sq ft) sf sf sf
18 Percent BUA 59% 60% 59%
19 Design storm (inches) 1.0 in 1.0 in 1.0 in
20 Design volume of SCM (cu ft) 3341 cf 8506 cf
21 Calculation method for design volume SCS SCS SCS
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 drainage area(s):