SW4200501_Signed Supplement-EZ_20200602

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
(PROJECT INFORMATION
1
Project Name
Project Area ac)
Lewisville Middle School
2
64.93
3
Coastal Wetland Area ac
0
4
Surface Water Area (ac)
1-28
5
Is this project High or Low Density?
High
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 ve etated setback remain vegetated?
Yes
9
Is BUA other that as listed in .1 0034 c-d out of the setback?
Yes
10
Is streambank stabilization proposed on this project?
Yes
(NUMBER AND TYPE OF SCMs:
11
Infiltration System
Bioretention Cell
0
12
0
13
Wet Pond
1
14
Stormwater Wetland
1
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 1
Treatment Swale
0
22
IiDry Pond
0
23
StormFilter
0
24
Silva Cell
0
25
Bayfilter
0
26
Filterra
0
FORMS LOADED
DESIGNER CERTIFICATION
27
_Name and Title:
Kenneth Lorinq - Principal
28
Organization:
CLH Desi n PA
29
Street address:
400 Regency Forest Drive, Suite 120
30
City, State, Zip:
Cary, NC
31
Phone numbers :
919-319-6716
32
Email;
27518
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.
,.�'P�H CA,g11 a
NO
-.;
SEAL -
23953 =
"o
14
Signature of Designer
Date
(.Z, - Z - Z oz.a

DRAINAGE AREAS
1
Is this a high density project?
Yes
2
L3
If so, number of drainage areas/SCMs
2
Is all/part of this project subject to previous rule
versions?
No
FORMS LOADED
DRAINAGE AREA INFORMATION
Entire Site
1
2
4
Type of SCM
Total BUA in project (sq ft
N/A
WET POND
WETLAND
5
388120 sf
355141 sf
32979 sf
6(sq
New BUA on subdivided lots (subject to permitting)
ft
N/A
N/A
N/A
7
New BUA outside of subdivided lots (subject to
ermittin (sf)
387296 sf
354317 sf
32979 sf
8
Offsite - total area (sq ft
0
19602 sf
0
9
Offsite BUA (sq ft
0
19602 sf
0
10
Breakdown of new BUA outside subdivided lots:
Parking (sq ft)
105490 sf
105490 sf
0
Sidewalk (sq ft
25206 sf
23189 sf
2017 sf
Roof (sq ft
62264 sf
62264 sf
0
Roadway (sq ft)
121582 sf
93234 sf
28348 sf
Future (sq ft
11326 sf
8712 sf
2614 sf
Other, please specify in the comment box
below (sg ft
61428 sf
0
61428 sf
0
0
11
New infiltrating permeable pavement on
subdivided lots (sq ft
0
i
0
12
New infiltrating permeable pavement outside of
subdivided lots s ft
0
0
13
Exisitng BUA that will remain (not subject to
ermittin sq ft
824 sf
824 sf
0
14
Existing BUA that is already permitted (sq ft
0
6
0
15
Existing BUA that will be removed (sq ft
0
0
0
16
Percent BUA
13.7%
46.1 %
36,8%
17 [Design
storm (inches)
N/A
1 in
1 in
18
Design volume of SCM cu ft)
N/A
31547 cf
2822 cf
19
Calculation method for design volume
N/A
SIMPLE
SIMPLE
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
20 drainage area(s):
"'Other" BUA includes gravel fire lane and "rock dust" track; in -lieu of aquiring
,an agreement with offsite parcels for future BUA, we have allotted 100% of
'the offsite (0 45 ac - 19602 sf) to be impervious, this area has been added to
'the "offsite" BUA section of the wet pond

WET POND
1 Drainage area number
2� Design volume of SCM (cu fl}
CeNeltALMDC FR0M 02H .1050
__ __ 1
31547 cf
3
Is the SCM sized to treat the SW from all surfaces at build -out?
des
Yes
4
is the SCM located away from contaminated soils?
S
What are the side slopes of the SCM (H:V)?
3:1
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?
Drawdown Orifice
10
If applicable, will the SCM be cleaned out after construction?
Yes
11
Does the maintenance access comply with General MDC (8)?
Yes
121
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)?
No
Yes
Yes
14
Is there an O&M Agreement that complies with General MDC (11)?
15
Is there an O&M Plan that Complies with General MDC (12)?
16
Does the SCM follow the device specific MDC?
Yes
17
Was the SO designed by an NC licensed professional?
Yes
WET POND
H 5
Method used HRT
18
19
Has a stage/storage table been provided in the calculations?
Yes
20
Elevation of the excavated main pool depth (bottom of sediment
removal) (fmsl)
822.50
21
Elevation of the main pool bottom -(top of sediment removal) (fmsl)
823.00
22
Elevation of the bottom of the vegetated shelf (fmsl)
826.00
23
Elevation of the permanent pool (fmsl)
826.50
24
Elevation of the top of the vegetated shelf (fmsl)
827.00
25
Elevation of the temporary pool (fmsl)
827.33
26
Surface area of the main permanent pool (square feet)
30040:1
27
Volume of the main permanent pool (cubic feet)
87015 cf
28
,Average depth of the main pool (feet)
3.13 ft
29
Average depth equation used
Equation 3
30
If using equation 3, main pool perimeter (feet)
796.0 ft
31
If using equation 3, width of submerged veg. shelf (feet)
10 ft
32
Volume of the forebay (cubic feet)
14313 cf
33
Is this 15-20% of the volume in the main pool?
Yes
34
Clean -out depth for forebay (inches)
54 in
35
Design volume of SCM (cu ft)
31547 cf
36
Is the outlet an orifice or a weir?
Orifice
37
If orifice, orifice diameter (inches)
2.5
38
If weir, weir height (inches)
N/A
39
If weir, weir length (inches)
N/A
40
Drawdown time for the temporary pool (days)
4.5
41
Are the inlet(s) and outlet located in a manner that avoids short-
circuiting?
Yes
42
.Are berms or baffles provided to improve the flow path?
No
43
Depth of forebay at entrance (inches)
66 in
44
Depth of forebay at exit (inches)
60 in
45
Does water flow out of the forebay in a non -erosive manner?
Yes
46
Width of the vegetated shelf (feet)
6 ft
47
Slope of vegetated shelf (H:V)
6:1
48
Does the orifice drawdown from below the top surface of the
;permanent pool?
Yes
491
Does the pond minimize impacts to the receiving channel from the 1-
yr, 24-hr storm?
Yes
50
Are fountains proposed? (If Y, please provide documentation that
MDC(9) is met)
No
51
Is a trash rack or other device provided to protect the outlet system?
Yes
52
Are the dam and embankment planted in non4untping huff grass?
Yes
53
Species of turf that will be used on the dam and embankment
No Mow Seed Mix
as a planting plan been provided or the vegetate shelf?
es
ADDITIONAL INFORMATION
55
Please use this space to provide any additional information about
the wet pond(s):
3 9:01 AM 6/2/2020

STQRMWATER WETLAND
ADDITIONAL INFORMATION
561Please use this space to provide any addiI onal information about Ilia
storrnwater wetland(s):
Line 52, 50 plants for 201 SF In shallow water zone (line.52 will not let user type
anything)
Wetland 5 9:01 AM 6/2/2020