SW5211202_Stormwater Narrative_20220203

Date: December 12, 2021
Project: Nash 97 Solar, LLC
11250 West NC Hwy 97
Middlesex, North Carolina 27557
Nash County
PROJECT NARRATIVE
CYPRESS CREEK
RENEWABLES
The purpose of this narrative is to summarize the as -built improvements for the Nash 97 Solar, 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 5-Megawatt (MW) AC (7.07 MW DC) solar power generation facility located on a 39.08-acre lease -controlled
area in Nash 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), southeast of the main array field (See As -Built ALTA Survey). No significant site grading was performed
— only minimal vegetation clearing, utility trenching, subgrade preparation a gravel drive, concrete equipment pads and a single
DOT -permitted access driveway with an 18-inch diameter culvert (off NC Hwy 97). A chain link perimeter fence encloses the
facility.
The solar site is functioning adequately as a Low -Density Project with stormwater released as dispersed flow. The project site
areas are completely vegetated and match pre -construction terrain, except for a gravel drive and concrete equipment pads. The
site has retained its existing sloping topography that sheet flows overland drainage to an existing unnamed tributary (Non -
Jurisdictional Ditch) beyond the northcentral lease boundary. The site terrain slopes from south (elevation 314 ft) to the northwest
direction, to an elevation of 270 feet for a drop of 44 feet (See Civil Plan Sheet C4). The tributary flows northwest to Turkey
Creek (Class C; Neuse River Basin). Downstream vegetation areas provide natural stormwater treatment and dissipation of
sheet flow runoff before it enters the tributaries. 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 does not meet the design criteria for a Disconnected Impervious System (DIS). Per the NCDEQ Stormwater Design
Manual Section E-6. Solar Farms, ground mounted solar panels are considered pervious when they are configured in
accordance with Recommendation 2. The project calculated Disconnection Length is 70.3% of the total solar panel width, which
is below the minimum 80% threshold (See BUA Calculations Package: Row Spacing: 13.10-ft; Solar Panel Width: 9.21-ft; Slope:
5.7%, average). However, the solar panel heights are below 10-ft, design complies with Recommendation 6 (See Solar Panel
and Racking System Details).
The CCR Operations and Maintenance (0&M) Team performs regular inspections on a quarterly basis. 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. The submitted Operation & Maintenance Agreement will enhance and/or reinforce the
Maintenance Plan that is already in -place for the project; thereby, meeting Post -Construction Stormwater Permit requirements
for a Low -Density project.
Cypress Creek Renewables, 5310 S. Alston Ave. Bldg. 300 Durham, NC 27510 919.240.4815