SW3211203_BUA Allocations_20220223

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Project: BG Stewart Solar' LLC
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Union County, NC _- ;
5182
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Date: 12/13/2021
By: J. Graham, PE :,;.'9 ��P.•�:
Checked: M. Carreon, PE •�,r��,T"CA,,�.
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1. SSW-SWU-101 BUA Calculation Backup
Total Property Area (ac)
48.01
ac
Parcels 1 and 2, Civil Plans (sheet C3, 4/9/2015)
Total Coastal Wetlands Area (ac)
0
ac
Surface Waters (ac)
0
ac
Total Project Area (ac)
39.2
ac
LOD per Civil Plans (sheet C1, 4/9/2015)
Basin informatinn
n—i.— Ares 1
Receiving Stream Name
Beaverdam Creek
Yadkin Pee -Dee River Basin
Stream Class
WS-V
Stream Index Number
13-17-40-11
Total Drainage Area (sf)
1,707,552
On -site Drainage Area (sf)
1,707,552
Off -site Drainage Area (sf)
0
Proposed Impervious Area (sf)
18,319
0.42
ac
% Impervious Area (total)
1.07%
38.78
ac (Grassed Areas)
Impervious Surface Area
t_ee oV» max.
below)
nrainnva Aron 7
On -site Buildings/Lots (sf)
0
On -site Streets (sf)
16947
From DWG
On -site Parking (sf)
0
On -site Sidewalks (sf)
0
Other on -site (sf)
IS71
1372
Equipment Pads from DWG
199
Foundation Posts (Piles); assume 4-inch diameter (Total
No. of Posts =2,277 )
Future (sf)
0
Off -site (sf)
0
Existing BUA (sf)
0
Total (sf)
18319
2. NOTES
a. Union County is a Phase 2 Tipped County
b. Subject to MS4 requirements per 15A NCAC 02H.1016
c. BUA is 24% max.

Project: BG Stewart Solar Farm, LLC
Union County, NC
Date: 12/13/2021
By: J. Graham, PE
Checked: M. Carreon, PE
Cypress Creek Renewables
3. NCDEQ Stormwater Design Manual (Rev. 12-13-2018) 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 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. However, it does not meet the
Disconnection Length threshold (see 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)
18.17
per Zoning Site Plan (sheet L2, 1/29/2015)
Row Spacing (ft)
8.10
per Zoning Site Plan (sheet L2, 1/29/2015)
Average Slope (%)
5.20%
per Civil Plans (sheet C4, 4/9/2015)
< 8%
Yes
DL Ratio
44.6%
See plans for overall vegetated areas
>80%
No
Figure 1: Disconnection of Now path between solar panels when average slope is
less than 8%.
Solar Panel Width a X R
Disconnection Length 2 X R
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Avg Slops I S%
Solar Panel Width = X R
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.