WQCS00054_NOV-2020-DV-0011 Response_20200114

f . t
500 North Main Street
Suite # 600
Monroe, NC 28112
T. 704-296-4210
January 14, 2020
Mr. W. Corey Basinger
Regional Supervisor
Water Quality Regional Operations Section
Mooresville Regional Office
610 East Center Ave., Suite 301
Mooresville, NC 28115
Subject: Notice of Violation & Intent to Issue Civil Penalty
Tracking #: NOV-2020-DV-0011
Sanitary Sewer Overflows — December 2019
Collection System Permit — WQCS00054
Union County
Dear Mr. Basinger:
Union County has received the NOV referenced above for collection system overflows.
Explanations of the overflows were on the BIMS Overflow Reporting Forms submitted by Union
County Public Works (UCPW) to the NCDEQ. However, we have added a few additional facts
in the explanations below.
Incident # Date Location
201901892 12/13/2019 4015 Sardis Church Road
201901955 12/23/2019 4015 Sardis Church Road
Response:
The SSO listed in this section were due to I&I introduction during heavy rains and flash flooding. The system
associated with this area was inundated with floodwaters and increased flows at CCWRF. The new CCWRF EQ
system was being utilized to attenuate peak flows experienced during storm events, however, during construction of
the new gravity system an existing 8-inch gravity main located on the north side of Sardis Church Road was thought
to be abandoned and as such was not reconnected to the new gravity system. This line is connected to a 12-inch line
on the south side of Sardis Church Road, however, without the parallel 8-inch line available to convey flow the
collection system experienced a severe hydraulic condition. The 8-inch line has been connected to avoid this
restriction in the future. Plans are being developed with our CIP team to resolve to improve general hydraulics in this
area.
Union County Public Works has underwent a comprehensive Master Plan (Black & Veatch) and improvements
strategy in efforts to better identify areas of improvement within the Crooked Creek basin. Efforts such as flow
monitoring studies (CDMSmith/Hydrostructures and Frazier Engineering) to identify areas of inflow and infiltration,
capacity assessments of the CCWRF and associated lift stations, lift station assessments to
c identify aging infrastructure, among others.
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As a result of these studies, UCPW has developed a CIP plan to address certain areas of concern.
A significant plant upgrade at the Crooked Creek WRF was completed including new headworks, a 3MG EQ
basin, and process improvements. Total cost is $7.775M project also included a new 10.3 MGD influent PS,
new headworks containing new bar screens, compactor, and grit removal/dewatering, and relocation of
1200' of 18" gravity sewer.
I&I flow studies have been conducted by CDMSmith (Hydrostructures) and Frazier Engineering. These
studies have narrowed the basin into concentrated sub -basins to target I&I reduction. The intended
approach is a find -fix method to utilize funding efficiently and consistently. The first initial 2017 target area is
southwest of CCWRF in the Indian Trail area south of Hwy 74, west to the Union/Mecklenburg county line.
Additional areas for I&I abatement are being evaluated.
Following the spill on 12/13/2020, a team was developed from our maintenance staff to optimize the amount flow into
the new EQ. By the efforts of staff we were able to adjust and refine total volume entering the EQ during high peak
intensity situations. Further refinement is underway.
Incident # Date Location
201901893 12/13/2019 2722 Waxhaw Marvin Road
201901956 12/23/2019 2722 Waxhaw Marvin Road
Response:
The SSO listed in this section were due to I&I introduction during heavy rains and flash flooding. The sanitary sewer
overflow occurred at the Marvin School Pump Station, out of a sanitary sewer manhole. We suspect the inflow is a
result of a recent new development that is under construction. Further investigations are underway including smoke
testing the entire basin.
Incident # Date Location
201901954 12/23/2019 910 Sharon Road
Response:
The SSO listed in this section were due to I&I introduction during heavy rains and flash flooding. The sanitary sewer
overflow occurred at the 21/25 Pump Station, out of a sanitary sewer manhole. This pump station is at 80% design for
replacement. Funding has been allocated for this project. I&I efforts are being designed including flow monitoring,
pipe lining, and manhole rehab.
UCPW also has an aggressive Capital Improvement Program throughout the next 5 years. The
projects include:
Crooked Creek Basin Improvements - $23,900,000
➢ Suburban Estates PS and FM - $1,000,000.00
➢ Waxhaw Interceptor—$5,400,000
➢ WW PS Improvements - $3,500,000
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UCPW's current CIP projects are also ongoing with projects including:
➢ Blythe Creek Sewer Improvements - $6,200,000
➢ Forest Park PS Replacement & Interceptor Improvements - $3,345,000
➢ Crooked Creek I&I Study & Remediation - $476,000
Union County Public Works continues to invest funds into SSES work, capital improvements,
maintenance and operations to improve the wastewater collection system. If further information
or details regarding the CCWRF Improvements, as well as, the CIP projects listed above are
required, please feel free to contact Greg Morgan, Superintendent/ORC, at 704-289-3288 or
myself at 704-296-4215.
Thank you for your consideration on this issue.
Sincerely,
4� 4'k
Andrew Neff, PE
(i!
Water/Wastewater Division Director
cc: Hyong Yi, Public Works Administrator
Josh Brooks, Assistant Director, Water/Wastewater Operations
Greg Morgan, Utility Field Services Superintendent/ORC
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