SW6211202_Stormwater Narrative_20220223

Date: December 12, 2021
CYPRESS CREEK
RENEWABLES
Project: Innovative Solar 48, LLC
22400 Andrew Jackson Highway (US-74 Alt.)
Maxton, North Carolina 28364
Robeson County
PROJECT NARRATIVE
The purpose of this narrative is to summarize the as -built improvements for the Innovative Solar 48, LLC project ("Project"),
which was built in 2015; discuss post -construction drainage conditions and demonstrate compliance with NC DEMLR's post -
construction stormwater permitting requirements. Cypress Creek Renewables (CCR) performed an internal audit and discovered
that the project was missing said permit — i.e., it was not obtained by the previous Developer/Engineer prior to beginning
construction. The CCR Engineering Team verified that the project is in a State Post -Construction Stormwater Permitting
jurisdiction, gathered the available project documentation, completed the NC DEMLR stormwater management application
forms, and issued a fee payment check with the goal of bringing the operational solar facility into compliance.
The project is a 4.99-Megawatt (MW) AC (6.32 MW DC) solar power generation facility located on a 34.91-acre lease -controlled
area within an existing 63.25-acre parcel in Robeson County. The facility consists of fixed tilt solar photovoltaic (PV) panel tables
supported on driven steel piles (posts) and pad -mounted inverters. The solar PV system is connected to the Duke Energy
Progress (DEP) utility electric grid at a Point of Interconnection (POI) within the southeast portion of the lease boundary, on the
north side of Andrew Jackson Highway (See As -Built ALTA Survey). No significant site grading was performed — only minimal
vegetation clearing, utility trenching and subgrade preparation for a gravel internal access road, concrete equipment pads and
a DOT -permitted access driveway with an 18-inch diameter culvert. A chain link perimeter fence (7-ft total height) encloses the
facility and includes a vegetated landscape buffer along the residential -facing exterior segments.
The solar site is functioning adequately as a Low -Density Project. The project onsite areas are completely vegetated and match
pre -construction terrain, except for gravel road and concrete equipment pads. The site remains relatively flat (elevation 174 ft)
with a minimal gradient (approximately 1%) to the north and northeast, where onsite drainage runoff discharges via overland
sheet flow to an unnamed tributary of the Lumber River (High Quality Waters; Class B; Sw; Lumber River Basin). Downstream
exterior vegetation areas have remained intact, providing natural stormwater treatment and dissipation of sheet flow runoff
before it enters the river's tributary. Onsite, the grass areas beneath the solar panels and between rows allow for rainwater
infiltration, dissipation, and dispersal as overland drainage sheet flow to downstream areas.
The project also functions as a Disconnected Impervious System (DIS), complying with the design criteria outlined in the NCDEQ
Stormwater Design Manual Section E-6 Solar Farms, which considers ground mounted solar panels as pervious when they are
configured in accordance with Recommendation 2. The calculated Disconnection Length is 85% of the total solar panel width
(See BUA Calculations Package: Row Spacing: 11-ft; Solar Panel Width: 12.94-ft; Slope: 1 %). Also, since the solar panel heights
are below 10-ft, the project design complies with Recommendation 6 (See Solar Panel and Racking System Details).
Lastly, the CCR Operations and Maintenance (0&M) Team performs regular inspections on a quarterly basis (minimum). 0&M
personnel perform grass mowing; minor seeding/replanting of bare areas; debris and trash removal; panel washing/cleaning;
onsite road repairs; and electrical equipment testing as needed. The submitted Operation & Maintenance Agreement will
enhance and/or reinforce the Maintenance Plan that is already in -place for the project; thus, making approval of the Post -
Construction Stormwater Permit an administrative formality.
Cypress Creek Renewables, 5310 S. Alston Ave. Bldg. 300 Durham, NC 27510 919.240.4815