SW6240205_Supplement-EZ Form_20241016

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
1PROJECT INFORMATION
1 Project Name Hoke County High School Replacement
2 Project Area(ac) 18.52
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? 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 I 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(DIS) 0
21 Treatment Swale 0
22 Dry Pond 0
23 StormFilter 0
24 Silva Cell 0
25 Bayfilter 0
26 Filterra 0
FORMS LOADED
DESIGNER CERTIFICATION
27 Name and Title: Kevin Lindsay,PE
28 Organization: Crawford Design Company
29 Street address: 230 W.Pennsylvania Ave.
30 City,State,Zip: Southern Pines,NC 28387
31 Phone number(s): [phone]
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

DRAINAGE AREAS
1 Is this a high density project? Yes
2 If so, number of drainage areas/SCMs 3
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 3
4 Type of SCM Bioretention Bioretention none
5 Total drainage area (sq ft) 864092 130198 205795 528099
6 Onsite drainage area (sq ft) 864092 130198 205795 528099
7 Offsite drainage area (sq ft) 0 0 0 0
8 Total BUA in project(sq ft) 489614 sf 40526 sf 121422 sf 327571 sf
New BUA on subdivided lots(subject to
9 permitting)(sq ft) sf sf sf sf
New BUA not on subdivided lots(subject to
10 permitting)(sf) 152895 sf 40019 sf 52644 sf 60137 sf
11 Offsite BUA(sq ft) sf sf sf sf
12 Breakdown of new BUA not on subdivided lots:
- Parking (sq ft) 57141 sf 16357 sf 15800 sf 24984 sf _
-Sidewalk(sq ft) 17381 sf 2490 sf sf 14891 sf
- Roof(sq ft) 41434 sf 21172 sf sf 20262 sf
- Roadway(sq ft) sf sf sf sf
- Future(sq ft) sf sf sf sf
-Other, please specify in the comment box
below(sq ft) sf sf 36844 sf sf
New infiltrating permeable pavement on
13 subdivided lots(sq ft) sf sf sf sf
New infiltrating permeable pavement not on
14 subdivided lots(sq ft) sf sf sf sf
Existing BUA that will remain (not subject to
15 permitting)(sq ft) 336719 sf 507 sf 68778 sf 267434 sf
16 Existing BUA that is already permitted (sq ft) 336719 sf 507 sf 68778 sf 267434 sf
17 Existing BUA that will be removed (sq ft) sf sf sf sf
18 Percent BUA 29% 31% 38% 23% _
19 Design storm(inches) 1.0 in 1.0 in _ 1.0 in 1.0 in
20 Design volume of SCM (cu ft) 21681 cf 3556 cf 6788 cf 11338 cf
21 Calculation method for design volume simple method simple method I simple method simple method
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 drainage area(s):
line 12 : other BUA is new tennis court; line 15:there are 336,719 sf of
existing IA within the 863,795 sf project area; line 17 : does not include an
ex. tennis court; line 18: (11.24-7.73/(19.83-7.73)x100=29%; SCMs 1 &2
capture and treat 34,421 cf of runoff--exceeding 21,681 cf design volume.

BIORETENTION CELL
1 Drainage area number 1 2
2 Minimum required treatment volume(cu ft) 3556 cf 6788 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)? 6:1 6:1
Does the SCM have retaining walls, gabion walls or other engineered
6 side slopes? No No
Are the inlets,outlets,and receiving stream protected from erosion
7 (10-year storm)? Yes Yes
Is there an overflow or bypass for inflow volume in excess of the
8 design volume? Yes Yes
9 What is the method for dewatering the SCM for maintenance? Drawdown Orifice 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)? N/A N/A
If the SCM is on a single family lot,does(will?)the plat comply with
13
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) 245.95 245.57
19 Bottom of the bioretention cell(fmsl) 251.40 251.00
20 Ponding depth of the design storm (inches) 12 in 12 in
21 Surface area of the bioretention cell(square feet) 10831 sf 18171 sf
22 Design volume of SCM(cu ft) 12671 cf 19449 cf
23 Is the bioretention cell used for peak attenuation? Yes Yes
24 Depth of peak attenuation over planting surface(in) 13.080 20.400 I
25 Height of peak attenuation outlet above the planting surface(in) 12 in 12 in
26 Infiltration rate of the in situ soil(inch/hour) r 0.075 0.130
27 Diameter of the underdrain pipes(if applicable) 4 in 4 in
28 Does the design include Internal Water Storage(IWS)? Yes Yes
29 if so,elevation of the top of the IWS(fmsl) 249.9 249.5
30 Elevation of the planting surface(fmsl) 251.4 251
What type of vegetation will be planted? (grass,trees/shrubs,
31 other)?I Grass Grass
32 Media depth(inches) 30 in 30 in
33 Percentage of medium to coarse washed sand by volume 85% 85%
34 Percentage of fines(silt and clay)by volume 10% 10%
35 Percentage of organic matter by volume 5% 5%
36 Type of organic material pine bark fines pine bark fines
37 Phosphorus Index(P-Index)of media(unitless) <30 <30
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) N/A N/A
41 Type of mulch, if applicable N/A N/A
42 How many clean out pipes are being installed? 2 3
43 Type of pretreatment that will be used: Gravel Gravel
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
44 bioretention cell(s):
Drawdown: Each SCM has two or more drain lines that connect to the outlet
structure separately. Each of these has cleanouts no more than 90 feet
apart and a screw cap at the base of the upturned tee in the riser that can be
opened to drain the SCM through the riser outlet or pump. SCM 1 can be
drained by gravity outlet pipe of riser. SCM 2 will require a pump to fully
drain.