SW5200702_SuppEZ-Signed_20200827

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1
Project Name ....
Snow Hill Road Pump Station
2
Project Area (ac) ....
21.91.
....
3
Coastal Wetland Area (ac)
0 ....
4
Surface Water Area (ac)
0
5
Is this project High or Low Density?
Low
6
Does this..project use an off -site SCM?
No
COMPLIANCE WITH 02H .1003(4)
7
Width of vegetated setbacks provided (feet)
N/A - no surface water or buffers on site
8
Will the vegetated setback remain vegetated?
N/A
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
0
12
Bioretention Cell
0
13
Wet Pond.
0 ..
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
D Pond
0
23
StormFilter
0 ....
24
Silva Cell...
0
25
Bayfilter ....
0 ....
26
Filterra
0
IfflIOl l ldlic
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
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O�jNNE E. ally signed by Corinne E.
s,Date: 2020.08.27 14:58:37-0
Signature of Designer
Wilson
'Wte

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 i a areas
drama low density g.
2
Is all/part of this project subject to previous rule
5
versions?
No
FQEMn ..aa P.M.
DRAINAGE AREA INFORMATION
Entire Site
4
Type of SCM
N/A
5
ITotal drainage area (sq ft
670509 sf
6
Onsite drainage area (sq ft)
128117 sf
7
Offsite drainage area (sq ft)
542392 sf
8
Total BUA in project (sq ft)
34597 sf
New BUA on subdivided lots (subject to permitting)
9
(sq ft)
sf
New BUA not on subdivided lots (subject to
10
permitting) (so
34597 sf
11
Offsite BUA (sq ft)....
218987 sf
12
Breakdown of new BUA not on subdivided lots:
sf
Parking (sq ft)
835 sf
Sidewalk (sq ft)
2525 sf
Roof (sq ft)
2830 sf
Roadway (sq ft.,
....
sf....
Future (sq ft)
sf....
Other, please specify in the comment box
below (sq ft)
28407 sf
New infiltrating permeable pavement on
13
subdivided lots (sq ft)
sf
New infiltrating permeable pavement not on
14
subdivided lots (sq ft)
sf
Existing BUA that will remain (not subject to
15
permitting) (sq ft)
sf
16
Existing BUA that is already permitted (sq ft)
sf
17
Existing BUA that will be removed (sq ft)
4449 sf
18
Percent BUA
8%.......
19
Design storm (inches)
N/A
20
Design volume of SCM (cu ft)
N/A
21
Calculation method for design volume
N/A
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22
drainage area(s):
Other
= driveway, Removed impervious established prior to
the baseline
period (2001) for the Percent BUA calculation
LID 1
LID 2
N/A
N/A
228484 sf
442025 sf
27894 sf
100223 sf
200590 sf
341802 sf
9095 sf
25502 sf
sf
sf
9095 sf
25502 sf
135100 sf
83887 sf
sf
835 sf
sf
2525 sf....
sf
2830 sf....
sf
sf ....
....
sf
sf
9095 sf 19312 sf
sf sf
sf sf
sf
sf.....
sf.....
10%
N/A
N/A
N/A
sf
sf ....
4449 sf
7%u ....
N/A
N/A
N/A

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)
3H:1V
5 Maximum velocity in the vegetated conveyances during the 10-year storm?
4.3
6 Are curb outlet swales proposed?
No
7 Maximum longitudinal slope of curb outlet swale(s) (%)
N/A
8 Bottom width of curb outlet swale(s) (feet)
N/A
9 Maximum side slope of curb outlet swale(s) (H:V)
N/A
10 Minimum length of curb outlet swale(s) (feet)
N/A
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
ADDITIONAL INFORMATION
15 Please use 00tnis space to provide any additional information about this low density project:
Three swales are proposed to carry a majority of the site stormwater from the site. Two swales drain to the first drainage area, and one to the
second drainage area. These swales are proposed with permanent lining to avoid erosive flows during and after construction,
and to reduce
velocities to below 4.5 Is. Outlet protection is used at one swale outlet that carries off -site flow to the forested area south of the site. All swales
were designed with outlet protection to disperse and slow stormwater flow prior to entering existing channels and forested areas.
Water that is
not carried in vegetated swales will sheet flow toward existing drainage channels. Offsite drainage area from the Durham Tech Community
C011ege Campus (constructed before the baseline date) will be connected to a new pipe designed for the 25-year storm to extend
the discharge
oint of the outflow to the south of the new drive wa .Outlet rotection was de ned for the 10- ear storm event.
Swale
Drainage
BUA
PerviousFO.41
Q
Slope
Va„ —F24
Flow depth
#
Area
(ac)
area(cfs)
N
(fps)
(ft)
ac
__Laces
1
3.20
2.58
0.62
14.74
1.00
4.50
2.10
2
0.22
0.12
0.10
1.40
2.00
4.50
0.40
3
1.20
0.19
1.01
3.00
2.00
4.50
0.60
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
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