SW5220302_Supplement-EZ Form_20220502

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1
I Project Name
NCNG JFHQ Helipad
2
Project Area ac
12.55
3
Coastal Wetland Area ac
0
4
Surface Water Area ac
0.09
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
50'
8
Will the vegetated setback remain vegetated?
Yes
9
Is BUA other that as listed in .1003 4 c-d out of the setback?
Yes
10
Is streambank stabilization proposed on this project?
No
NUMBER AND TYPE OF SCMS:
11
Infiltration System
0
12
Bioretention Cell
1
13
Wet Pond
0
14
Stormwater Wetland
0
15
Permeable Pavement
0
16
Sand Filter
0
17
1 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
Storm Filter
0
24
Silva Cell
0
25
Ba liter
0
26
Filterra
0
FORMS LOADED
DESIGNER CERTIFICATION
27
Name and Title:
Frank Slinsk . P.E.. Senior Project Manager
28
Organization:
Timmons Group
29
Street address:
5410 Trinity Road. Suite 102
30
City, State Zip:
Ralei h. NC 27607
31
Phone numbers :
Email:
919 866-4505
32
_
[e-mail]
Certlfaalion Stalament:
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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Signature of Designer
5
Date

DRAINAGE AREAS
1
Is this a high density project?
Yes
2
If so, number of drainage areas/SCMs
1
3
Is all/part of this project subject to previous rule
versions?
No
FORMS LOADED
DRAINAGE AREA INFORMATION
Entire Site
1
4
Type of SCM
Bioretention
5
Total BUA in project (sq ft
119081 sf
119081 sf
6permitting)
New BUA on subdivided lots (subject to
s ft
7permitting)
New BUA outside of subdivided lots (subject to
sf
118275 sf
118275 sf
8
Offsite - total area (sq ft
1017 sf
1017 sf
9
Offsite BUA (sq ft
836 sf
836 sf
10
Breakdown of new BUA outside subdivided lots:
- Parking (sq ft
118275 sf
118275 sf
- Sidewalk (sq ft
sf
sf
- Roof (sq ft
sf
sf
- Roadway s ft
sf
sf
- Future (sq ft
sf
sf
- Other, please specify in the comment box
below (sq ft
11
New infiltrating permeable pavement on
subdivided lots (sq ft
12
New infiltrating permeable pavement outside of
subdivided lots (sq ft
13permitting)
Exisitng BUA that will remain (not subject to
s ft
sf
sf
14
lExistina BUA that is already permitted (sq ft
15
Existing BUA that will be removed (sq ft
16
Percent BUA
22%
45%
17
Design storm inches
1 in
18
Design volume of SCM cu ft
10028 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):

BIORETENTION CELL
1 1Drainage area number
2 jDesign 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?
Yes
4
Is the SCM located away from contaminated soils?
Yes
5
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
lWhat 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
12
Does the drainage easement comply with General MDC (9)?
No
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
15
Is there an O&M Plan that complies with General MDC (12)?
Yes
16
1 Does the SCM follow the device specific MDC?
Yes
17
1was the SCM designed by an NC licensed professional?
Yes
BIORETENTION
CELL MDC FROM 02H .1052
18
SHWT elevation (fmsl)
420.00
19
Bottom of the bioretention cell (fmsl)
422.50
20
Ponding depth of the design storm (inches)
12 in
21
Surface area of the bioretention cell (square feet)
10050 sf
22
Design volume of the bioretention cell (cubic feet)
10028 cf
23
Is the bioretention cell used for peak attenuation?
Yes
24
Depth of peak attenuation over planting surface (in)
21 in
25
Height of peak attenuation outlet above the planting surface (in)
18 in
26
j Infiltration rate of the in situ soil (inch/hour)
<2
27
Diameter of the underdrain pipes (if applicable)
6 in
28
Does the design include Internal Water Storage (IWS)?
Yes
29
if so, elevation of the top of the IWS (fmsl)
424
30
Elevation of the planting surface (fmsl)
426
31
What type of vegetation will be planted? (grass, trees/shrubs, other)?
Grass
32
Media depth (inches)
36 in
33
Percentage of medium to coarse washed sand by volume
82%
34
Percentage of fines (silt and clay) by volume
9%
35
Percentage of organic matter by volume
9%
36
Type of organic material
Peat Moss
37
Phosphorus Index (P-Index) of media (unitless)
5
38
lWill compaction be avoided during construction?
Yes
39
Will cell be maintained to a one inch/hour standard?
Yes
40
Depth of mulch, if applicable (inches)
N/A
41
Type of mulch, if applicable
N/A
42
How many clean out pipes are being installed?
12
43
Type of pretreatment that will be used:
None
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
44 bioretention cell(s):
IThe SCM is on state owned land so a drainage easement is not applicable.
Bioretention 1 3:41 PM 5/2/2022