SW4240503_Supplement-EZ Form_20240913

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name WILDERNESS RESERVE PHASE 3
2 Project Area (ac) 48.91
3 Coastal Wetland Area (ac) 0
4 Surface Water Area (ac) 0
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? 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
14 Stormwater Wetland
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
22 Dry Pond
23 StormFilter
24 Silva Cell
25 Bayfilter
26 Filterra
FORMS LOADED
DESIGNER CERTIFICATION
27 Name and Title: GREG GOTSCH
28 Organization: LAND RESOURCES MANAGEMENT
29 Street address: 118 CHERRY STREET
30 City, State, Zip: BLACK MOUNTAIN, NC 28711
31 Phone number(s): 828 900-8700
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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09/06/2024
Seal Date

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
1DRAINAGE AREA INFORMATION + I Entire Site LD 1
4 Type of SCM NA
5 Total drainage area (sq ft) I 3225747.86 2130416
6 Onsite drainage area (sq ft) 3225747.86 2130416
7 Offsite drainage area (sq ft) 0 0
8 Total BUA in project (sq ft) 239843 sf 135336 sf
New BUA on subdivided lots (subject to permitting)
9 (sq ft) _ 165000 sf 100000 sf
New BUA not on subdivided lots (subject to
10 permitting) (sf) 75104 sf _ 35336 sf
11 Offsite BUA (sq ft) sf sf
12 Breakdown of new BUA not on subdivided lots:
- Parking (sq ft) sf
- Sidewalk (sq ft) sf
- Roof(sq ft) sf
- Roadway (sq ft) 75104 sf 35336 sf
- Future (sq ft) sf
- Other, please specify in the comment box
below (sq ft) sf
New infiltrating permeable pavement on subdivided
13 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 7% 6%
19 Design storm (inches) NA NA
20 Design volume of SCM (cu ft) NA NA
21 Calculation method for design volume NA
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 'drainage area(s):
I
I

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 sf
5 Maximum velocity in the vegetated conveyances during the 10-year storm? 4.3
6 Are curb outlet swales proposed? No
7 Maximum longitudinal slope of curb outlet swale(s) (%) NA
8 Bottom width of curb outlet swale(s) (feet) NA
9 Maximum side slope of curb outlet swale(s) (H:V) 1 NA
10 Minimum length of curb outlet swale(s) (feet) NA
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 downslope 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:
Please Note that maximum velocity was determined by increasing Flow for each swale using NAG software until the section
becomes unstable. Please note the maximum velocities represent an unvegetated condition failure. All other calculations are for
the 10-year storm event, permanent stabilization.
Drainage Pervious
Swale Area BUA area C Q Slope Va„ow Vactual Flow depth
# _ (ac) (ac) (ac) (cfs) (%) (fps) (fps) (ft)
1 0.94 0.09 0.86 0.31 0.31 14.60 15.00 4.21 ft/s 0.24
2 1.08 0.27 0.81 0.42 0.42 11.46 15.00 4.3 ft/s 0.31
3 0.13 0.09 0.04 0.75 0.75 14.90 15.00 2.85 ft/s 0.15
4 0.15 0.10 0.05 0.72 0.72 14.90 15.00 3.01 ft/s 0.16
5 0.07 0.04 0.03 0.63 0.63 14.54 15.00 2.13 ft/s 0.11
6 0.28 0.15 0.13 0.62 0.62 11.60 15.00 3.17 ft/s 0.22
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