SW6231001_Supplement-EZ_20240424

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name Lancaster
2 Project Area(ac) 10.82
3 Coastal Wetland Area(ac) -
4 Surface Water Area(ac) -
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 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 1
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 Dry Pond 0
23 'StormFilter 0
24 Silva Cell 0
25 Bayfilter 0
26 Filterra 0
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FORMS LOADED
7DESIGNER CERTIFICATION
27 Name and Title: _ Carlo Pardo, PE
28 Organization: Bowman North Carolina,Ltd.
29 Street address: 4006 Barrett Drive,Suite 104
30 City,State,Zip: Raleigh,NC 27609
31 'Phone number(s): 919-553-6570
32 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.
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DRAINAGE AREAS
1 r0 Is this a high density project? I 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
Is all/part of this project subject to previous rule
5 ;versions? No
FORMS LOADED
DRAINAGE AREA INFORMATION Entire Site 1 1 —'1
[ —
4 Type of SCM - ' Infiltration Basin
5 Total drainage area(sq ft) 471494 sf 393707
6 Onsite drainage area(sq ft) 471494 sf 386138
7 Offsite drainage area(sq ft) 7569
8 Total BUA in project(sq ft) 100880 sf 108449 sf
New BUA on subdivided lots(subject to permitting)
9 ,(sq ft) 64000 sf 64000 sf
New BUA not on subdivided lots(subject to
10 ,permitting)(sf) 36880 sf 36880 sf _
11 Offsite BUA(sq ft) 7569 sf
12 Breakdown of new BUA not on subdivided lots:
-Parking(sq ft) _
-Sidewalk(sq ft) 5026 sf 5026 sf
-Roof(sq ft)
-Roadway(sq ft) 31854 sf 31854 sf
-Future(sq ft) __
-Other,please specify in the comment box
below ss 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�
16 Existing BUA that is already permitted(sq ft) _
17 Existing BUA that will be removed(sq ft) 4117 sf 4117 sf
18 Percent BUA 21.40% 27.5%
19 Design storm(inches) 1.0 in
20 Design volume of SCM(Cu ft) 36158 cf
21 Calculation method for design volume Simple Method
•ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 drainage area(s):
Line 11-The 7,569 sf of off-site impervious is made up of ROW and neighboring parcels that were assumed
100%BUA.
In the pond calculations the pre-developed drainage area has 11,240 sf(0.26 ac.)of BUA.The 4,117 sf listed
above is the existing,on-site BUA.The remaining 7,123 sf of BUA is off-site,and is either included in Line 11,
or will not drain to the infiltration basin after development.

INFILTRATION SYSTEM
1 ;Drainage area number I 1
2 Minimum required treatment volume(cu ft) 9774 cf
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 or enter"Vertical'for
trenches)? 3:1
6 Does the SCM have retaining walls,gabion walls or other engineered
4side 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? I Pump(preferred)
10 If applicable,will the SCM be cleaned out after construction? Yes
11 Does the maintenance access comply with General MDC(8)? - j Yes
12 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)? 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 designed by an NC licensed professional? Yes
"INFILTRATION SYSTEM MDC FROM 02H.1051
18 Proposed slope of the subgrade surface(%) 0%
19 Are terraces or baffles provided? No
20 Type of pretreatment: Fore_bay
Soils Data
21 Was the soil investigated in the footprint and at the elevation of the
infiltration system? Yes
22 SHWT elevation(fmsl) 193.00
23 Depth to SHWT per soils report(in) 132.00
24 Ground elevation at boring in soils report(fmsl) 204.00
25 Is a detailed hydrogeologic study attached if the separation is
between 1 and 2 feet? N/A
26 Soil infiltration rate(in/hr) 4 5.00
27 Factor of safety(FS) (2 is recommended): j 2.00
Elevations
29 Bottom elevation(fmsl) ( 200 ft
30 Storage elevation(fmsl) 201.7 ft
31 Bypass elevation(fmsl) 201.7 ft
For Basins Only
32 Bottom surface area(ft2) 19800 ft
33 Storage elevation surface area(ft2) 22760.ft
For Trenches Only
34 Length(ft)
35 Width(ft)
36 'Perforated pipe diameter,if applicable(inches) _
37 Number of laterals
38 Total length of perforated piping
39 Stone type,if applicable
40 Stone porosity(%)
41 Is stone free of fines?
42 Is the stone wrapped in geotextile fabric?
43 Has at least one inspection port been provided?
I Volumes/Drawdown
L 44 Design volume of SCM(cu ft) 36158 cf
45 Time to draw down(hours) 18.9 hrs
ADDITIONAL INFORMATION
46 'Please use this space to provide any additional information about the
infiltration system(s):
Line 26-The soils report found the infiltration rate of the soil for DA 1 to be 10.0"/hr.A
=more conservative value of 5.0"/hr was used in the calculations,to account for
clogging of the soils that will happen over time.
Infiltration 1 4:21 PM 1/17/2024