SW3161201_4 - Supplemental-EZ-2018-Version-2_5/5/2020

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name
2 Project Area (ac)
3 Coastal Wetland Area (ac)
4 Surface Water Area (ac)
5 Ils this project High or Low Density?
6 1 Does this project use an off -site SCM?
Conservancy at Waxhaw Creek Phase 2
53.85
0
0
Low
No
COMPLIANCE WITH 02H .1003(4)
7
Width of vegetated setbacks provided (feet)
40'
8
Will the vegetated setback remain vegetated?
Yes
9
Is BUA other that as listed in .1003(4)(c-d) out of the setback?
No
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
2
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:
Richard L. Modlin - Civil Engineer
28
Organization:
Richard L. Modlin, PE
29
Street address:
7215 Terrace Drive
30
City, State, Zip:
Charlotte, NC 28211
31
1 Phone number(s):
980.322.4191
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 thai
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 1
Is all/part of this project subject to previous rule
3 versions? No
FORMS LOADED
DRAINAGE
AREA INFORMATION
Type of SCM _
Total BUA in project (sq ft)
New BUA on subdivided lots (subject to permitting)
(sq ft)
Entire Site
1
4
wet pond
5
189307 sf
6
126321 sf
7
New BUA outside of subdivided lots (subject to
permitting) (sf) _
Offsite - total area (sq ft)
62986 sf
8
292723 sf
9
Offsite BUA (sq ft)
55603 sf
10
Breakdown of new BUA outside 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)
62986 sf
11
New infiltrating permeable pavement on subdivided
lots (sq ft)
12
New infiltrating permeable pavement outside of
Isubdivided lots (sq ft)
13
Exisitng BUA that will remain (not subject to
permitting) (sq ft)
14
Existing BUA that is already permitted (sq ft)
15
Existing BUA that will be removed (sq ft)
16
Percent BUA
8.07%
17
Design storm (inches)
2.95
18
Design volume of SCM (cu ft)
38397 cf
19
Calculation method for design volume
Simple Method
ADDITIONAL
INFORMATION
20
Please use this space to provide any additional information about the
drainage area(s):

WET POND
1
Drainage area number
1
2
21 Design volume of SCM (cu ft)
GENERAL MDC FROM 02H .1050
3 Is the SCM sized to treat the SW from all surfaces at build -out?
16635 cf
21762 cf
Yes Yes
4
Is the SCM located away from contaminated soils?
Yes
Yes
5
What are the side slopes of the SCM (H:V)?
3:1
3:1
6
Does the SCM have retaining walls, gabion walls or other
engineered side slopes?
No
No
7
Are the inlets, outlets, and receiving stream protected from erosion
(10-year storm)?
Yes
Yes
8
Is there an overflow or bypass for inflow volume in excess of the
design volume?
Yes
Yes
9
What is the method for dewatering the SCM for maintenance?
Drawdown Orifice
Drawdown Orifice
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)?
Yes
Yes
13
If the SCM is on a single family lot, does (will?) the plat comply with
General MDC (10)?
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
161
Does the SCM follow the device specific MDC?
Yes
Yes
17 Was the SCM designed by an NC licensed professional?
WET POND MDC FROM 02H .1053
181 Method used
Yes
SA/DA
Yes
SA/DA
19
Has a stage/storage table been provided in the calculations?
Yes
Yes
20
Elevation of the excavated main pool depth (bottom of sediment
removal) (fmsl)
517.00
541.00
21
Elevation of the main pool bottom -(top of sediment removal) (fmsl)
518.00
542.00
22
Elevation of the bottom of the vegetated shelf (fmsl)
521.50
546.00
23
Elevation of the permanent pool (fmsl)
522.00
546.50
24
Elevation of the top of the vegetated shelf (fmsl)
522.50
547.00
25
Elevation of the temporary pool (fmsl)
523.42
549.45
26
Surface area of the main permanent pool (square feet)
12198
7271
27
Volume of the main permanent pool (cubic feet)
38208 cf
22157 cf
28
Average depth of the main pool (feet)
3.27 ft
3.32 ft
29
Average depth equation used
Equation 3
Equation 3
30
If using equation 3, main pool perimeter (feet)
420.3 ft
341.8 ft
311
If using equation 3, width of submerged veg. shelf (feet)
3.0 ft
3.0 ft
32
Volume of the forebay (cubic feet)
7213 cf
4325 cf
33
Is this 15-20% of the volume in the main pool?
Yes
Yes
34
Clean -out depth for forebay (inches)
42 in
54 in
35
Design volume of SCM (cu ft)
16635 cf
21762 cf
36
Is the outlet an orifice or a weir?
Orifice
Orifice
37
If orifice, orifice diameter (inches)
2 in
2.5
38
If weir, weir height (inches)
N/A
N/A
391
If weir, weir length (inches)
N/A
N/A
40
Drawdown time for the temporary pool (days)
4.1
2.1
41
Are the inlet(s) and outlet located in a manner that avoids short-
circuiting?
Yes
Yes
42
Are berms or baffles provided to improve the flow path?
No
No
43
Depth of forebay at entrance (inches)
60 in
72 in
44
Depth of forebay at exit (inches)
54 in
66 in
45
Does water flow out of the forebay in a non -erosive manner?
Yes
Yes
46
Width of the vegetated shelf (feet)
6 ft
6 ft
47
Slope of vegetated shelf (H:V)
6:1
6:1
48
Does the orifice drawdown from below the top surface of the
permanent pool?
Yes
Yes
49
Does the pond minimize impacts to the receiving channel from the 1-
yr, 24-hr storm?
Yes
Yes
50
Are fountains proposed? (If Y, please provide documentation that
MDC(9) is met.)
No
No
51
1 Is a trash rack or other device provided to protect the outlet system?
Yes
Yes
52
Are the dam and embankment planted in non -clumping turf grass?
Yes
Yes
53
Species of turfthat will be used on the dam and embankment
tall fescue
tall fescue
Has a planting plan been provided or the vegetate shelf?
es Yes
ADDITIONAL INFORMATION
551
Please use this space to provide any additional information about
the wet pond(s):
Wet Pond 1 12:13 AM 4/30/2020

LOW DENSITY
DESIGN REQUIREMENTS FOR LOW DENSITY PROJECTS FROM 0211-1.1003
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
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 1 Please use this space to provide any additional information about this low density project:
Swale
#
Drainage
Area
(ac)
BUA
(ac)
Pervious
area
(ac)
C
Q
(cfs)
Slope
N
Va11°w
(fps)
Vatt°al Flow depth (ft)
(fps)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30