HomeMy WebLinkAboutSWA000022__02 Supplemental EZ Form - Signed_20201001SUPPLEMENT-EZ COVER PAGE
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PROJECT INFORMATION
1
Project Name
Courtyards at Emerald Lake
2
Project Area ac
33.54
3
Coastal Wetland Area ac
0
4
Surface Water Area ac
0.5
5
1 Is this project High or Low Density?
High
6
1 Does this project use an off -site SCM?
No
COMPLIANCE WITH 02H.1003(4)
7
Width of vegetated setbacks provided feet
100
8
Will the vegetated setback remain ve etated?
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?
No
NUMBER AND TYPE OF SCMs:
11
Infiltration System
Bioretention Cell
0
12
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-F$
0
20
Disconnected Impervious Surface (DIS)
0
21
Treatment Swale
0
22
1 Dry Pond
0
23
StormFilter
0
24
Silva Cell
0
25
Bay alter
0
26
Filterra
0
FORMS LOADED
DESIGNER CERTIFICATION
27
Name and Title:
Brian Rossi, PE/ Project Mana er
28
Organization:
EMH&T
29
Street address:
301 McCullough Dr
30
City, State, Zip:
Phone numbers :
Email:
Charlotte NC 28262
31
704-548-0333
32
brossi@emht.com
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.
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DRAINAGE AREAS
1 Is this a hi h density project? Yes
2 If so, number of drainage areas/SCMs 2
Is all/part of this project subject to previous rule
3 versions? No
FORMS LOADED
DRAINAGE AREA INFORMATION
Entire Site
1
2
4
Type of SCM
Wet Ponds
East Pond 1&2
West Pond 3
5
Total BUA in project s ft
486769 sf
373357 sf
91119 sf
6
New BUA on subdivided lots (subject to permitting)
(sq ft
358390 sf
266764 sf
74707 sf
7permitting)
New BUA outside of subdivided lots (subject to
s
128379 sf
106594 sf
16411 sf
8
Offsite - total area (sq ft
Offsite BUA (sq ft
Breakdown of new BUA outside subdivided lots:
Parking (sq ft
Sidewalk (sq ft
sf
13939 sf
9
-
sf
sf
10
5801 sf
5801 sf
sf
20067 sf
6302 sf
15341 sf
4908 sf
2694 sf
sf
Roof (sq ft
Roadway s ft
Future (sq ft)
Other, please specify in the comment box
below (sq ft
96210 sf
80545 sf
13717 sf
sf
sf
sf
sf
sf
sf
11
New infiltrating permeable pavement on
subdivided lots (sq ft
sf
sf
sf
12
New infiltrating permeable pavement outside of
subdivided lots (sq ft
sf
sf
sf
13permitting)
Exisitng BUA that will remain (not subject to
s ft
sf
sf
sf
14
Existing BUA that is already permitted (sq ft
sf
sf
sf
15
Existing BUA that will be removed (sq ft
sf
sf
sf
16
Percent BUA
34%
45%
50%
17
Design storm inches
(1-yr post) - (1yr
re)
(1-yr post) - (1yr
pre
18
Design volume of SCM cu ft
50661 cf
12408 Gf
19
Calculation method for design volume
Discrete NRCS
curve Number
Method I
Discrete NRCS
curve Number
Method
ADDITIONAL INFORMATION
20 ldrainage
Please use this space to provide any additional information about the
areas :
WET POND
1 Drainage area number 1&2 3
2 Design volume of SCM (cu ft) 50661 cf 12408 cf
f; Rai Mnr rAnm n7u Inca ice'
3
Is the SCM sized to treat the SW from all surfaces at build -out?
Yes
Fes
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
No
Yes
13
If the SCM is on a single family lot, does (will?) the plat comply with
General MDC (10)?
Is there an O&M Agreement that complies with General MDC (11)?
Is there an O&M Plan that complies with General MDC (12)?
No
14
15
Yes
Yes
Yes
Yes
Yes
Yes
16
Does the SCM follow the device specific MDC?
T7
Was the SCM designed by an NC licensed professlanai?
Yes
Yes
WCT anon unr. FPnM 117114 Ines
18
19
Method used
Has a stage/storage table been provided in the calculations?
SA/DA
SA/DA
Yes
Yes
20
Elevation of the excavated main pool depth (bottom of sediment
removal) (fmsl)
626.48
634.00
21
Elevation of the main pool bottom -(top of sediment removal) (fmsl)
627.48
635.00
22
Elevation of the bottom of the vegetated shelf (fmsl
634.00
638.80
23
Elevation of the permanent pool (fmsl)
634.50
639.28
24
Elevation of the top of the vegetated shelf (fmsl)
635.00
639.80
25
Elevation of the temporary pool (fmsQ
637.51
640.39
26
Surface area of the main permanent pool (square feet)
15636:1
6350:1
27
Volume of the main permanent pool (cubic feet)
60943 cf
19040 cf
28
Average depth of the main pool (feet)
3.90 ft
3.00 ft
29
Average depth equation used
Equation 2
Equation 2
30
If using equation 3, main pool perimeter (feet)
31
If using equation 3, width of submerged veg. shelf (feet)
32
Volume of the forebay (cubic feet)
21534 cf
3456 cf
33
Is this 15-20% of the volume in the main pool?
No
No
34
Clean -out depth for forebay (inches)
84 in
39 in
35
Design volume of SCM (cu ft)
50661 cf
12408 cf
36
Is the outlet an orifice or a weir?
Orifice
Orifice
37
If orifice, orifice diameter (inches)
2 in
1 in
38
If weir, weir height (inches)
39
If weir, weir length (inches)
40
Drawdown time for the temporary pool (days)
4.19
4.84
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)
73 in
70 in
44
Depth of forebay at exit (inches)
78 in
76 in
45
Does water flow out of the forebay in a non -erosive manner?
Yes
Yes
46
Width of the vegetated shelf (feet)
8 ft
loft
47
Slope of vegetated shelf (H:V)
8:1
10:1
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.)
Is a trash rack or other device provided to protect the outlet system?
Yes
Yes
51
No
No
52
Are the dam and embankment planted in non -clumping turf grass?
Yes
Yes
53
Species of turf that will be used on the dam and embankment
Bermuda Red
Bermuda Red
54
Has a planting plan been provided or the vegetated shelf?
yft Yes
ADDITIONAL INFORMATION
Please use this space to provide any additional information aboul the
w 55 et pana(a):
33, The basins were designed and approved in 2014, when the 15-20% was
not a requirement. The former DEQ manual requested "Approximately 20%"
volume in the forebays. Both basins provide over 20% of the below normal
pool volume providing extra settling opportunities for both basins.
Wet Pond 3 3:12 PM 7/10/2020