Meadowlark Solar, LLC - Meadowlark_NCDEQ SW Comments Submittal_5-24-18

Cypress Creek Renewables, 5310 South Alston Ave, Bldg 300, Durham, NC 27713 919.240.4815

May 24, 2018

NC Dept. of Environmental Quality
Division of Energy, Mineral, and Land Resources
512 North Salisbury Street
Raleigh, NC 27604
[phone]
Attn: Rick Riddle, Stormwater Engineer

Re: Meadowlark Solar
PIN # 1517-55-1245
825 Meadowlark Road
Dunn, Harnett County, NC

Dear Mr. Riddle,

In response to your email dated May 16, 2018, please find enclosed the following information in support of the
application for Post Construction Stormwater for the above referenced project:

• Updated pages 4 and 5 from the SWU-101 State Stormwater Permit Application Form, properly noting which items
have been provided and initialized.

• Per VI. Submittal Requirements item 3, since no permanent stormwater measures are being proposed the
supplemental and operation and maintenance forms are not being provided. However, per items 5 and 7, the
detailed narrative and supporting signed/sealed LID calculation summary sheet and Pre- and Post-development
drainage map are attached.

• Please noted that we also provided the updated plan set entitled, “Civil Permit Plans, Meadowlark Solar, LLC, 825
Meadowlark Rd, Dunn, Averasboro Twp, Harnett County, NC 28334, prepared by Cypress Creek EPC, dated
March 29, 2018, revised May 18, 2018,” which was revised to address the comments received during our erosion
control express review meeting with Jodi Pace in the Fayetteville Regional Office of NCDEQ on May 14, 2018.

I trust the above is satisfactory for your review and execution. Please contact me should you have any questions or
require any additional information.

Sincerely,

Kimberly Brooks
Civil Engineer
Cypress Creek Renewables
[e-mail]
828-279-9765

Enclosures

Project Narrative (Meadowlark Solar)
The proposed Meadowlark Solar project is located at 825 Meadowlark Road, Dunn, Harnett County, NC
(see Site Vicinity Map) within the Stony Run Watershed within the Cape Fear River Basin. The project
involves the construction of a new solar power generating facility, consisting of solar arrays containing
rows of photovoltaic solar panels mounted to steel racking and posts, and three inverter/transformer pad
areas. For security and safety, the entire facility will be surrounded by a 6’ high chain link fence with 3-
strands of barbed wire. Within the limits of disturbance (approximately 32 acres) the residual area of the
woods cleared, grubbed, and graded and the open fields will be mowed, disked, and graded only as
necessary to provide positive runoff towards the existing outfall points, and permanent stabilization
established. The project is expected to be constructed primarily with wheeled equipment, but tracked
vehicles will be used for post driving and possibly some other activities depending on ground conditions
at the time of construction. An appropriate seasonal permanent seed mix will be utilized to stabilize any
disturbed area.
Please refer to the attached pre- and post-development drainage area map (EX-1) which identifies the ten
(10) delineated drainage areas and provides a corresponding summary table for each area. Each table
identifies the hydrologic group, cover description, CN value, and calculated composite CN value for the
pre- and post-developed conditions. It should be noted that the post-development composite CN value
either was the same or less than the pre-development composite CN value. Please also note the summary
table on EX-1 shows the calculated built-upon area to be only 5.9% for the post-development conditions.
The attached Low Impact Development Calculation sheet references tables and calculations to comply
with the low density requirements ( < 6 percent built-upon area) and also by meeting the post-
development hydrologic criteria set out in Chapter 2 of the North Carolina Low Impact Development
Guidebook dated June 2009. This document (Table 2-2 Hydrologic fate of rainfall at Coweeta, NC, Water
02) allows for a target hydrology for the site of 5 percent runoff, 45 percent for infiltration, and 50 percent
evapotranspiration. Table 2-6, Allowable tolerance of hydrologic fates in Chapter 2: Achieving LID
Performance Goals Using a Hydrologic Cycle Approach of the Low Impact Development: A Guidebook for
North Carolina-2009 allows for a 15% tolerance for a Greenfield-Commercial development in the Coastal
Region, which would allow up to 20 percent runoff. As shown in the Post-Development Table, the
hydrologic fate falls within the allowable tolerance for a Greenfield-Commercial project within the Coastal
Region.
In addition to not increasing the composite CN value from pre- to post-development and meeting the
post-development hydrologic criteria set out in Chapter 2 of the North Carolina Low Impact Development
Guidebook dated June 2009, the pre-construction drainage patterns will be maintained and land
disturbance will be minimized to the best extent possible. Compacting beneath arrays and other pervious
areas will be minimized. Permanent seeding will be implemented as specified on the plans. Vertical
clearance of the panels will be limited to less than 10 feet. Herbicides and fertilizers will be used minimally
to limit vegetation where necessary.