20191305 Ver 1_Stan Aiken Trout Waiver Comments 02.05.20_20200205

February 05, 2020

Mr. Stan Aiken
NCDEQ Division of Energy Mineral and Land Resources
2090 U.S. 70 Highway
Swannanoa, NC 28778

RE: Highlands Retail Development Site Project
Trout Waiver Application
Additional Discussion

Dear Mr. Aiken,

Please find the following comments below discussed during telephone conversations regarding
the Trout Buffer Waiver submittals.

During conversations regarding the Trout Buffer Waiver submittals, you requested the following:

1. Top of Bank to be clearly labeled on the Civil Plans.
Please refer to the attached, Civil Plans. The plans have been updated to clearly show
the top of bank.

2. Concerns of creek impact and crossing on Cherrywood Drive instead of using existing
driveway off Highway 64.

A driveway off of U.S. 64 was pursued initially by the developer. NCDOT would have
permitted a commercial driveway at the southwest corner of the lot, as far away from
Cherrywood Drive as possible. It was discovered that there was an existing septic system
in the area of the proposed driveway, and that SW area of the site was the only area
suitable for a septic system. Therefore, the proposed driveway had to be relocated.
Unfortunately, there was not a driveway location on US 64 that both avoided disturbing
the septic area while having adequate spacing with Cherrywood Drive. (Closely spaced
intersections and access points increase the complexity for drivers, causing them to
navigate traffic situations where other vehicles may be entering or exiting the roadway to
and from many directions at once. Reducing the complexity creates safer driving
conditions.)

The decision was made that moving the proposed driveway to Cherrywood Drive would
reduce the potential conflicts and be a safer driveway location. NCDOT has permitted the
proposed driveway on Cherrywood Drive.

3. Requested details of a Pump Around System to be used during the Construction Phase
to work “In the Dry.”

Details of a Pump Around System have been added to the Civil Plans. The Pump Around
System is referenced on the Intermediate Phase ESPC Plan (Sheet 6) and detailed on
Sheet 16.

4. A detailed explanation of erosion control protocol during the Construction Phase.

A Construction Schedule & Notes for Work in Stream Buffers section was added to all
ESPC Plan pages (Sheets 5-8). This section discusses the construction sequence for the
buffer area and Erosion & Sediment Control BMP’s used. It also discusses that the work
in the buffer area shall be done in a timely matter, so that disturbance to the buffer area is
is minimized.

5. Discussion regarding stormwater detention system and how it will retain the water long
enough to cool it to a sufficient temperature before re-entering trout waters.

The manufacturer was contacted to discuss any studies or literature about temperature
cooling as it relates to detention time. Unfortunately, there were no studies by the
manufacturer of the underground detention chamber system (Cultec R-150XLHD Isolator
Row System) and it was found that Cooling Rate Studies have not been conducted on the
current system. Further online research was conducted regarding any studies available
on cooling rates of underground detention chamber systems. A study (Examination of
Thermal Impacts From Stormwater Best Management Practices) from the University of
New Hampshire was found and can be reviewed at the URL below:
https://www.unh.edu/unhsc/sites/unh.edu.unhsc/files/progress_reports/UNHSC%20EPA
_Thermal_Study_Final_Report_1-28-11.pdf

This study examined 4 years of runoff temperature data for 8 stormwater BMP’s in relation
to established environmental indicators. One of the BMP’s studied was a Storm Tech
Isolator Row System (which is a different brand of the same type of system as the Cultec
system specified in the plans). The Storm Tech system was found to be the most effective
of the 8 BMP’s at mitigating runoff temperatures.

Further, the proposed underground detention system is not discharging directly to the
stream. The storm water is discharged to a rip-rap apron located outside of the buffer
area, drainage will then flow through the undisturbed buffer area and into Wetland Area 2,
before finally entering the stream.

6. Additional information on the Riparian Planting Plan.
The landscape plan (Sheet 10) was revised to add planting details in the buffer area. First,
a riparian buffer seed mix was specified as permanent stabilization for disturbed areas in
the buffer. Specifications for the seed mix are included on the plan.

A planting schedule was included with a list of 5 shrub species (4 of which were identified
as species currently on the property during the Stream and Wetland Delineation). The
planting density (spacing) specified came from the NCDENR Guidelines for Riparian
Buffer Restoration. It was determined that planting shrubs in the sight distance triangle
could cause a safety concern for cars at the intersection of Cherrywood Drive turning onto
US 64. The sight triangle is shown on the plans, with a note that no shrubs were to be
planted in the sight triangle, and grasses in that area were to be mowed regularly and not
to exceed 3 feet.

7. Annotate on the Erosion and Sediment control pages that no plastic erosion control
matting will be used and only coconut coir matting will be utilized on the stream banks.
There was a note added to the ESPC pages (Sheets 5-8) that only coconut coir matting
could be used in the stream buffer areas. Coconut coir matting is also referenced in the
Construction Schedule & Notes for Work in Stream Buffers section (Sheets 5-8) and the
Pump Around System Detail (Sheet 16)

8. Update Trout Buffer Waiver with additional information given above.
The Trout Buffer Waiver was updated with additional information and uploaded via the
Project file link.

I hope you find the additional comments satisfactory for the issuance of the Trout Buffer Waiver.
Please feel free to contact me at my office regarding any questions you may have. You can reach
me at 256.536.2884 or feel free to reach out to Josselyn Lucas at 423.727.4476.

Sincerely,

Michelle R. Campbell
Project Manager
ARC Environmental, Inc.
P.O. Box 190
Brownsboro, AL 35741
[e-mail]
PH 256.536.2884
Mobile [phone]