SW3240306_Supplement-EZ Form_20240829

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name Lyle Creek Switching Station
2 Project Area(ac) 25.24
3 Coastal Wetland Area(ac) 0
4 Surface Water Area(ac) 0.5
5 Is this project High or Low Density? Low
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 0
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: Joe Puckett
28 Organization: HDR,Inc
29 Street address: 555 Fayetteville St#900
30 City,State,Zip: Raleigh,NC 27601
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.
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DRAINAGE AREAS
1 Is this a high density project? _ No _
2 If so,number of drainage areas/SCMs 0
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
FORMS LOADED
'DRAINAGE AREA INFORMATION Entire Site LD 1
4 Type of SCM N/A N/A
5 Total drainage area(sq ft) 1099454.4 1099454.4
6 Onsite drainage area(sq ft) 1099454.4 1099454.4
7 Offsite drainage area(sq ft) 0 0
8 Total BUA in project(sq ft) II 165964 sf 165964 sf
New BUA on subdivided lots(subject to
9 permitting)(sq ft) N/A N/A
New BUA not on subdivided lots(subject to
10 permitting)(sf) 165964 sf 165964 sf
11 Offsite BUA(sq ft) sf sf
12 Breakdown of new BUA not on subdivided lots:
-Parking(sq ft)
-Sidewalk(sq ft)
-Roof(sq ft)
-Roadway(sq ft) 48787 sf 48787 sf
-Future(sq ft)
-Other,please specify in the comment box
below(sq ft) 117176 sf - 117176 sf
New infiltrating permeable pavement on
13 subdivided lots(sq ft) N/A N/A
New infiltrating permeable pavement not on
14 subdivided lots(sq ft) N/A N/A
Existing BUA that will remain(not subject to
15 permitting)(sq ft) N/A N/A
16 Existing BUA that is already permitted(sq ft) N/A N/A
17 Existing BUA that will be removed(sq ft) N/A N/A
18 Percent BUA 15% 15%
19 Design storm(inches) 5.3 in 5.3 In
20 Design volume of SCM(cu ft) N/A N/A
21 Calculation method for design volume SCS TR-20 SCS TR-20
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 drainage area(s): _
Substation gravel pad considered in the BUA.
Entire project will be a single low density area with no proposed stormwater
control measures.

LOW DENSITY
DESIGN REQUIREMENTS FOR LOW DENSITY PROJECTS FROM 02H.1003
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) 3:1,4:1*
5 Maximum velocity in the vegetated conveyances during the 10-year storm? 4.19
6 Are curb outlet swales proposed? No
7 Maximum longitudinal 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? No
12 Is stormwater released at the edge of the setback as dispersed flow? Yes
13 Have stormwater outlets been designed to prevent do wnslope 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:
•The access road ditch uses side slopes of 3:1.All other vegetated conveyance around the perimeter of the pad uses 4:1 side
slopes.
Swale Drainage BUA Pervious Q Slope V„bN, V,,,,,,i Flow depth
# Area area C
(ac) (cfs) (%) (fps) (fps) (ft)
(ac) (ac) __
1 3.26 1.42 1.84 0.54 5.89 1.00 5.50 2.38 0.53
2 3.19 0.89 2.30 0.45 4.85 1.00 5.50 2.31 0.55
3 7.56 0.47 7.09 0.32 8.20 3.00 5.50 4.19 0.54
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