NC0085812_NOV-2020-LV-0270 Response_20200422

Department of Public Works
3 WaterMastewater Division
4600 Goldmine Road
Monroe, NC 28110
T. 704-289-1434
F.704-289-7395
www.unioncountync.gov
April 22, 2020
W. Corey Basinger,
Regional Supervisor
NCDEQ
610 East Center Avenue, Suite 301
Mooresville, NC 28115
Dear Mr. Basinger,
RECEIVE Et/ICI
WORDS
MOORESVILLE REGIONAL OFFICE
This letter is in response to NOV-2020-LV-0270, outlining the exceedance in monthly flow that
was experienced at our Grassy Branch WRF in February 2020. This exceedance was a result
of multiple rain events in the system (6.5" for the month) as well as the capacity issues we have
discussed in previous conversations.
In our meeting on 05/02/2019, we detailed our efforts in reducing the I&I that is entering the
Grassy Branch collection system. Since that meeting our Collections team has continued
working to improve the system. Such efforts include:
• Smoke testing
® Camera work and jetting
® Visual inspections during rain events
® Manhole rehab
® Installation of inflow collector dishes
As stated in our last response letter, we are also wrapping up a comprehensive flow monitoring
study by Frazier Engineering. This study will give us more than 12 months of data, including
both dry and wet season flow characteristics. Once we evaluate this data, we will then start
micro -monitoring to pinpoint areas in the system that could profit from future repair/rehab efforts.
Since that last response, we have submitted a task order to keep the six flow monitors in place
for an additional six months to further evaluate the system.
In addition to the I&I reduction, we are in the process of obtaining a SOC agreement with
NCDEQ and Union County in order to expand the plant. This will allow us to better address the
capacity of the WRF to treat the flows.

ng the
in the Grasy
We intend to continue our efforts finding and
at the Grassy Blranch WRF Slf ranch
have any even
as we address the treatment/capacity issues
questions or concerns please contact me at 704-296-4215.
Sincerely, Andrew Neff,/, PE
Water & Wastewater Division Director
Cc: Hyong Yi, Public Works Administrator
Josh Brooks, Asst. Div. Director, Water & Wastewater
Bart Farmer, WRF Superintendent
Greg Morgan, Utility Services Superintendent
Page 2