SW3221008_Supplement-EZ Form_20230208

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFQM'--'—"
1 Project Name
2 Project Area (ac)
3 Coastal Wetland Area (ac)
Is this project High or Low Density?
Does this project use an off -site SCM?
The Estates at Marvin Branch
27.71
Low
No
TH 02H .1003(4)
7 Width of vegetated setbacks provided (feet)
200
8 Will the vegetated setback remain vegetated?
Yes
9 f BUA is proposed in the setback, does it meet NCAC 02H.1003(4)(c-d)?
N/A
10 s streambank stabilization proposed on this project?
No
NU
11
Infiltration System 1
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
Storm Filter
24
Silva Cell
25
Bayfilter
26
Filterra
FORMS LOADED
DESIGNER CERTIFICATION
27
Name and Title:
Mason Greeson, PE Principal
28
Organization:
Civil & Environmental Consultants, Inc.
29
Street address:
City, State, Zip:
Phone number(s):
3701 Arco Corporate Drive, Suite 400
Charlotte, NC 28273
980.260.2120
30
31
32
Email:
[e-mail]
Certification Statement:
I certify, under penalty of lawthatthis 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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Signature of Designer
Date
2/8/2023

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
Curb Cut w/ grass
swale
Infiltration Basin
5
Total drainage area (sq ft)
1,207,091
179,467
6
Onsite drainage area (sq ft)
1,207,091
179,467
7
Offsite drainage area (sq ft)
0
0
8
Total BUA in project (sq ft)
236854 sf
35525 sf
9
New BUA on subdivided lots (subject to permitting)
(sq ft)
176000 sf
14898 sf
10
New BUA not on subdivided lots (subject to
permitting) (so
60854 sf
20627 sf
11
Offsite BUA (sq ft)
sf
sf
12
Breakdown of new BUA not on subdivided lots:
Parking (sq ft)
sf
sf
Sidewalk (sq ft)
11156 sf
2423 sf
Roof (sq ft)
sf
sf
Roadway (sq ft)
Future (sq ft)
Other, please specify in the comment box
below (sq ft)
49698 sf
18204 sf
sf
sf
13
New infiltrating permeable pavement on
Isubdivided lots (sq ft)
sf
sf
14
New infiltrating permeable pavement not on
subdivided lots (sq ft)
sf
sf
15
Existing BUA that will remain (not subject to
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
20%
20%
19
Design storm (inches)
3
20
Design volume of SCM (cu ft)
12721 cf
21
Calculation method for design volume
ADDITIONAL INFORMATION
22
Please use this space to provide any additional information about the
drainage area(s):
LD-1 Column is for the SCM required for Goose Creek rules only. The are
draining to this facility is for controlling the difference in Pre and Post runoff
volume for the 1 yr 24 hr storm event.

INFILTRATION SYSTEM
I Drainage area number 1
3
Is the SCM sized to treat the SW from all surfaces at build -out?
No
4
Is the SCM located away from contaminated soils?
Yes
5
What are the side slopes of the SCM (H:V or enter "Vertical" for
trenches)?
31
6
Does the SCM have retaining walls, gabion walls or other engineered
side slopes?
No
7
Are the inlets, outlets, and receiving stream protected from erosion
(10-year storm)?
Yes
8
Is there an overflow or bypass for inflow volume in excess of the
design volume?
Yes
9
What is the method for dewatering the SCM for maintenance?
Pump (preferred)
10
If applicable, will the SCM be cleaned out after construction?
Yes
11
Does the maintenance access comply with General MDC (8)?
Yes
12
Does the drainage easement comply with General MDC (9)?
Yes
13
If the SCM is on a single family lot, does (will?) the plat comply with
General MDC (10)?
N/A
14
Is there an O&M Agreement that complies with General MDC (11)?
Yes
15
Is there an O&M Plan that complies with General MDC (12)?
Yes
16
Does the SCM follow the device specific MDC?
Yes
18 Proposed slope of the subgrade surface (%) 0
19 Are terraces or baffles provided? No
20 Type of pretreatment: Other
Solla noro
21
Was the soil investigated in the footprint and at the elevation of the
infiltration system?
Yes
22
SHWT elevation (fmsl)
577.00
23
Depth to SHWT per soils report (in)
72.00
24
Ground elevation at boring in soils report (fmsl)
583.00
25
Is a detailed hydrogeologic study attached if the separation is
between 1 and 2 feet?
No
26
Soil infiltration rate (in/hr)
0.31
27
Factor of safety (FS) (2 is recommended):
2.00
I Elevations
29
1 Bottom elevation (fmsl)
581 ft
30
IStorage elevation (fmsl)
582. ft
31
1 Bypass elevation (fmsl)
582 ft
t-orbasms only
32 Bottom surface area (ft) 13703 ft
33 Storage elevation surface area (ft) 14567. ft
For Trenches Only
34
Length (ft)
35
Width (ft)
36
Perforated pipe diameter, if applicable (inches)
37
Number of laterals
38
Total length of perforated piping
39
Stone type, if applicable
40
Stone porosity (% )
41
Is stone free of fines?
42
Is the stone wrapped in geotextile fabric?
43
Has at least one inspection port been provided?
"'um
es/Drawtlown
44 Design volume of SCM (cu ft) 12721 cf
46 Please use this space to provide any additional information about the
infiltration system(s):
roposed Infiltration Basin with amended soils is to promote infitration of runoff from
fference in volume for Pre and Post developed conditions for the 1 year 24hr storm
ient per the Goose Creek regulations in Union County NC. Pretreament consists of
;reened gutters, stone/gravel outlet protection, overland sheet flow through
�getative media (grass), and debris removal on a biweekly basis thorughout he high
Infiltration 1 11:08 AM 2/8/2023

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)
101
5
Maximum velocity in the vegetated conveyances during the 10-year storm?
5
6
Are curb outlet swales proposed?
Yes
7
Maximum longitudinal slope of curb outlet swale(s) (%)
4
8
Bottom width of curb outlet swale(s) (feet)
2 ft
9
Maximum side slope of curb outlet swale(s) (H:V)
3:1
10
Minimum length of curb outlet swale(s) (feet)
100 ft
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
ADDITIO ORMATION
15 Please use this space to provide any additional information about this low density project:
The swale calcs are based on swales numbered 6-10, Swale 11 is for the bypass channel flow, and the vegetated path are natural
ground conveyance overland throguh the 200 vegetated buffer. Multiple side slopes are presented for each type. 3:1 for the
swales and 10:1 or flatter fro the vegetated paths.
Swale
#
Drainage
Area
BUA
(ac)
Pervious
area
C
Q
(cfs)
Slope
M
V.11-
(fps)
V.-I
(fps)
Flow depth
(ft)
1
2
3
4
5
1.48
0.41
1.07
0.50
5.65
3.30
5.00
4.70
0.60
6
1.23
0.33
0.90
0.50
4.69
4.11
5.00
4.79
0.49
7
1.17
0.38
0.79
0.50
3.55
3.95
5.00
4.33
0.48
8
0.68
0.23
0.45
0.50
2.59
2.22
5.00
3.21
0.30
9
0.62
0.23
0.39
0.50
2.36
2.22
5.00
3.12
0.29
10
0.62
0.23
0.39
0.50
2.36
1.49
5.00
2.72
0.33
11
7.87
0.00
7.87
0.50
30.06
1.00
5.00
4.37
1.14
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
r30