SW6230606_Supplement-EZ Form_20231009

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECTINFORMATI
1 Project Name BENHAVEN EMERGENCY SERVICES 13
2 Project Area(ac) 2.49
3 Coastal Wetland Area(ac) 0
4 Surface Water Area(ac) 0
5 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) 30
8 Will the vegetated setback remain vegetated? YES
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
12 Bioretention Cell 1
13 Wet Pond
14 Stormwater Wetland
15 Permeable Pavement
16 iSand Filter
17 Rainwater Harvesting(RWH)
18 Green Roof
19 Level Spreader-Filter Strip(LS-FS)
20 Disconnected Impervious Surface(DIS)
21 Treatment Swale
22 Dry Pond
23 StormFilter
24 Silva Cell
25 Bayfilter
26 Filterra
FORMS LOADED
F
NER CERTIFICATION
Name and Title: BLAIR P.PITTMAN,SITE DEPT.MANAGER
Organization: BOBBITT DESIGN BUILD,INC.
Street address: 600 GERMANTOWN DR
City,State,Zip: RALEIGH,NC 27607
Phone number(s): 919-851-1980
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 that the engineering plans,
specifications,operation and maintenance agreements and other supporting information are consistent with the information provided here.
Designer
Signature of Designer
Seal Date

DRAINAGE AREAS
1 Is this a high density project? Yes
2 If so,number of drainage areas/SCMs 1
3 Does this project have low density areas? No
4 If so,number of low density drainage areas 0
Is all/part of this project subject to previous rule
5 versions? No
FORMS LOADED
DRAINAGE AREA INFORMATION Entire Site 1
4 Type of SCM Bioretention Cell
5 Total drainage area(sq ft) 108392 62984
6 Onsite drainage area(sq ft) 108392 60962 sf
7 Offsite drainage area(sq ft) 2022
8 Total BUA in project(sq ft) 32000 sf 34022 sf
New BUA on subdivided lots(subject to
9 permitting)(sq ft)
New BUA not on subdivided lots(subject to
10 permitting)(so
11 Offsite BUA(sq ft) 2022 sf
12 Breakdown of new BUA not on subdivided lots:
Parking(sq ft) 17950 sf 17950 sf
Sidewalk(sq ft) 1850 sf 1850 sf
Roof(sq ft) 12200 sf 12200 sf
Roadway(sq ft)
Future(sq ft)
Other,please specify in the comment box
below(sq ft)
New infiltrating permeable pavement on
13 subdivided lots(sq ft)
New infiltrating permeable pavement not on
14 subdivided lots(sq ft)
Existing BUA that will remain(not subject to
15 permitting)(sq ft)
16 Existing BUA that is already permitted(sq ft)
17 Existing BUA that will be removed(sq ft)
18 Percent BUA 30% 54%
19 IDesign storm(inches) 1.0 in
20 1 Design volume of SCM(cu ft) 2850 cf
21 Jualculation method for design volume Simple Method
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 drainage area(s):
Although only 1746 SF of offsite area is existing impervious,all 2022 SF is
considered as BUA for calcultion purpose as per 15A NCAC 02H
.1003(3)(b)

BIORETENTION CELL
1 Drainage area number 1
2 Minimum required treatment volume cu ft c
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
Does the SCM have retaining walls,gabion walls or other
6
engineered side slopes? No
Are the inlets,outlets,and receiving stream protected from erosion 7
(10-year storm)? Yes
Is there an overflow or bypass for inflow volume in excess of the
8
design volume? Yes
9 What is the method for dewatering the SCM for maintenance? Pump(preferred)
10 If applicable,will the SCM be cleaned out after construction? N/A
11 Does the maintenance access comply with General MDC(8)? Yes
12 Does the drainage easement comply with General MDC(9)? Yes
If the SCM is on a single family lot,does(will?)the plat comply with
13
General MDC(10)? N/A
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 Does the SCM follow the device specific MDC? Yes
17 Was the SCM designedy an NC licensedprofessional? Yes
BIORETENTION CELL MDC FROM 02H.1052
18 SHWT elevation(fmsl) 274.42
19 Bottom of the bioretention cell(fmsl) 276.67
20 Ponding depth of the design storm(inches) 12 in
21 Surface area of the bioretention cell(square feet) 2850 sf
22 Design volume of SCM(cu ft) 2850 cf
23 Is the bioretention cell used for peak attenuation? Yes
24 Depth of peak attenuation over planting surface(in) 10 in
25 Height of peak attenuation outlet above the planting surface(in) 12 in
26 Infiltration rate of the in situ soil(inch/hour) N/A
27 Diameter of the underdrain pipes(if applicable) 4"&6"
28 Does the design include Internal Water Storage(IWS)? Yes
29 if so,elevation of the top of the IWS(fmsl) 279
30 Elevation of the planting surface(fmsl) 280.5
31 What type of vegetation will be planted? (grass,trees/shrubs,
other)? Grass
32 Media depth(inches) 30 in
33 Percentage of medium to coarse washed sand by volume 75%-85%
34 Percentage of fines(silt and clay)by volume 8%-10%
35 Percentage of organic matter by volume 5%-10%
36 Type of organic material Pine bark fines
37 Phosphorus Index(P-Index)of media(unitless) 10 to 30
38 Will 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? 11
43 1 ype or pretreatment tha will be useGrassed Swale
ADDITIONAL INFORMATION
44 Please use this space to provide any additional information about
the bioretention cell(s):
Bioretention 3 2:12 PM 10/9/2023