SW6211202_BUA Allocations_20220223

Project: Innovative Solar 48, LLC
Robeson County, NC
Revised Date: 12/12/2021
By: J. Graham, PE
Checked: M. Carreon, PE
Cypress Creek Renewables
1. SSW-SWU-101 BUA Calculation Backup
,,IIIIIIIII,I//
5182 f
#000001 its
Total Property Area (ac)
34.91
ac
Per As -Built ALTA/NSPS Land Title Survey dated 3/7/2016
Total Coastal Wetlands Area (ac)
0
ac
Surface Waters (ac)
0
ac
Total Project Area (ac)
33.00
ac
LOD as per ESC Approval Letter dated 6/1/201S (SWPPP)
Basin Information
Drainage Area 1
Receiving Stream Name
Lumber River
Lumber River basin
Stream Class
B; SW, HQW
Stream Index Number
14-(4.5)
Total Drainage Area (sf)
1,437,480
On -site Drainage Area (sf)
1,437,480
Off -site Drainage Area (sf)
-
Proposed Impervious Area (sf)
46,827
1.07
Jac
% Impervious Area (total)
3.26%1
31.93
Jac (Grassed Areas)
Impervious Surface Area
(See BUA max.
below)
Drainage Area 1
On -site Buildings/Lots (sf)
0
On -site Streets (sf)
45589
From DWG
On -site Parking (sf)
0
On -site Sidewalks (sf)
0
Other on -site (sf)
1238
1056
Three equipment pads, from DWG
182
Foundation Posts (Piles); assume 4-inch diameter (Total No.
of Posts =2,084 )
Future (sf)
0
Off -site (sf)
0
Existing BUA (sf)
0
Total (sf)
46827
2. NOTES
a. Robeson County is not a Phase 2 County, not a CAMA County
b. Subject to High Quality Watershed requirements per 15A NCAC 02H.1021
c. BUA is 12% max.

Project: Innovative Solar 48, LLC
Robeson County, NC
Revised Date: 12/12/2021
By: J. Graham, PE
Checked: M. Carreon, PE
Cypress Creek Renewables
3. NCDEQ Stormwater Design Manual (Rev. 12-1.3-2018) E-6 Solar Farms
Regulatory Requirements:
DEMLR allows solar panels associated with ground -mounted solar farms to considered pervious
Other structures associated with the solar farm - buildings, entrance roads, transformers (concrete pads) and
footings (steel piles/posts) are still considered impervious.
Recommendation 2: Disconnect runoff from solar panel arrays
The project has been installed to allow for vegetation under and in between the solar arrays; and the terrain
slopes are less than 8% along the disconnection flow path (see tabulated dimensions below).
Recommendation 6: Limit vertical clearance to less than or equal to 10 feet
The project solar panel maximum heights are less than 10 feet, which helps prevent erosion and scourig along
the dripline (see Solar Panel and Racking System Details provided).
Solar Panel Width (ft)
12.94
per Overall Site Plan dated 8/14/2015
Row Spacing (ft)
11.00
per Overall Site Plan dated 8/14/2015
Average Slope (%)
1.0%
approx. per USGS Contours
< 8%
Yes
(average on -site ground elevation is 174.0)
DL Ratio
85.0%
>80%
Yes
Figure 1: Disconnection of flow path between solar panels when average slope is
less than 8%.
Solar Panel Width a X It
Disconnection Length t X it
01'Wonrection Fits Path
s ..
Avg Slope S 8%
Solar Panel Width . X It
In general, the minimum disconnection length between two rows of solar panels is equal to the
width of each row, as shown in Figure 1. However, some panel layouts include horizontal gaps
between individual modules that allow stormwater to drip off the panels at intervals much
smaller than the width of each row. In these instances, the solar farm can be designed with a
smaller disconnection length, provided that they will not cause concentration of stormwater
runoff. The disconnection length should not be less than 80% of the total solar panel width.