SW3220601_Supplement-EZ Form_20221012

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1
JProject Name
Project Area ac
Coastal Wetland Area ac
Surface Water Area ac
Is this project High or Low Density?
Willoughby Electrical Substation
2
9.99
3
4
1.81
5
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?
7
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
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
Ba filter
26
Filterra
FORMS LOADED
DESIGNER CERTIFICATION
27
Name and Title:
Joe Ervin P.E.
28
Organization:
Pike Engineering, LLC
29
Street address:
123 N White St
30
City, State, Zip:
Ft Mill, SC 29715
31
Phone numbers :
843.697.0606
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
..........
- 215 y�
fjZ�Q r! E
Sea/
Signature of Designer
10/11 /2022
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
5
Is all/part of this project subject to previous rule
versions?
No
FORMS LOADED
DRAINAGE AREA INFORMATION
Entire Site
LID 1
4
Type of SCM
5
Total drainage area (sq ft)
435164
435164
6
Onsite drainage area (sq ft)
435164
435164
7
Offsite drainage area (sq ft)
8
Total BUA in project (sq ft)
17500 sf
17500 sf
9
New BUA on subdivided lots (subject to
permitting) (sq ft)
10
New BUA not on subdivided lots (subject to
permitting) (so
17500 sf
17500 sf
11
Offsite BUA (sq ft)
12
Breakdown of new BUA not on subdivided lots:
Parking (sq ft)
Sidewalk (sq ft)
Roof (sq ft)
Roadway (sq ft)
Future (sq ft)
Other, please specify in the comment box
below (sq ft)
17500 sf
17500 sf
13
New infiltrating permeable pavement on
subdivided lots (sq ft)
14
New infiltrating permeable pavement not on
Isubdivided lots (sq ft)
15
Existing BUA that will remain (not subject to
permitting) (sq ft)
16
Existing BUA that is already permitted (sq ft)
17
Existing BUA that will be removed (sq ft)
18
Percent BUA
4%
4%
19
Design storm (inches)
20
1 Design volume of SCM (cu ft)
21
lCalculation method for design volume
ADDITIONAL INFORMATION
22
Please use this space to provide any additional information about the
drainage area(s):

LOW DENSITY
DESIGN
REQUIREMENTS FOR LOW DENSITY PROJECTS FROM 02H .1003
Is project below density thresholds set forth in the applicable stormwater rule?
Yes
1
2
Does project maximize dispersed flow and minimize channelization of flow?
Yes
3
Has the use of piping been minimized per. 1 003(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?
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?
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
JPiease use this space to provide any additional information about this low density project:
Side slopes for all proposed swales have been revised from 2.5H:1V to 3H:1V from previous submittal
Swale
#
Drainage
Area
ac
BUA
(ac)
Pervious
area
ac
C
Q
(cfs)
Slope
( % )
Va„o„
(fps)
Va , a,
(fps)
Flow depth
(ft)
1
3.75
0.27
3.48
0.48
13.40
0.50
6.00
1.34
1.23
2
2.93
0.08
2.85
0.47
10.20
2.00
5.00
3.29
0.56
3
1.07
0.08
0.99
0.47
3.72
1.00
5.00
1.83
0.35
4
0.40
0.07
0.33
0.50
1.48
5.00
5.00
2.26
0.13
5
0.38
0.11
0.27
0.54
1.52
6.00
5.00
2.47
0.13
6
3.21
0.30
2.91
0.50
11.80
0.50
5.00
2.00
0.73
7
0.13
0.02
0.11
0.50
0.48
4.00
5.00
1.25
0.06
8
0.70
0.05
0.65
0.49
2.54
5.00
5.00
2.56
0.22
9
10
11
12
13
See accompanying hydrologic/hydraulic calculations
14
DA swale 6 = DA SW3 + DA SW4 +DA SW5 + DA SW6 = 3.21 ac
15
IDA Swale 1 = DA POST A3 + DA Post A6 + DA POST WATKINS RD = 3.75 ac
16
"C values for Swales 1 and 6 are weighted based on contributing drainage areas
17
18
19
20
21
22
23
24
25
26
27
r28