NC0031879_RESP_NOVNOI2020LV0301_20200518

May 11, 2020
CITY OF MARION
PUBLIC WORKS DEPARTMENT OFFICE OF THE
P.O. Drawer 700 PUBLIC WORKS DIRECTOR
Marion, NC 28752
MAY 18 2020
Mr. G. Landon Davidson, P.O., Regional Supervisor i ieoional Operations
Water Quality Regional Operations Section, NCDEQ iegional Office
Asheville Regional Office
2090 U.S. Hwy 70
Swannanoa, NC 28778
Subject: Notice of Violation
Tracking #: NOV-2020-LV-0301
Permit NO. NCO031879
Corpening Creek WWTP
McDowell County
Dear Mr. Davidson,
I am writing in response to your letter dated April 20, 2020 and received by the City of Marion
on April 24, 2020, requesting, within 60 business days of the receipt of the letter, an explanation
of violations occurring at the Corpening Creek W WTP during the week of February 9, 2020.
The violations in question involved the weekly average for TSS being exceeded for the week of
February 9 and the monthly average for TSS being exceeded for the month of February. In
response to this Notice of Violation, both violations were caused by the settling process
becoming upset due to high flows received on February 11-12. The high flows were caused by
heavy downpours of rain that occurred over short periods of time during the morning and early
afternoon hours of February 11 and during the evening hours of February 12. Readings taken
from the plant's effluent flow chart indicated flow spikes as high as 4.35 MG on February 11 and
as high as 3.5 MG on February 12.
W WTP Personnel responded immediately to the hydraulically upset plant by adjusting the
aeration and flow to reduce the impact of the flow spikes. Personnel were able to regain control
of the settling process relatively quickly, but the high flows did result in the TSS levels being out
of compliance for two days (February 11 & 12). These two days of non -compliant TSS levels
caused the weekly average to exceed the weekly limit. They also caused the monthly average to
exceed the monthly limit.
The City of Marion Public Works Department is proactive with regard to elimination of inflow
and infiltration (I&I) from its wastewater collection system. The department conducted ,a

comprehensive I&I study from 2014-2016 that resulted in the elimination of 317 sources of I&I.
Please reference Compliance Agreement C14-001 and the associated final report dated April 29,
2016 for more documentation of the I&I reduction that was accomplished by the study. Since
2016, our efforts to eliminate I&I have continued. The Utility Maintenance Department
performs smoke testing frequently, especially in the areas that are known to be prone to I&I. For
example, one problematic area in Clinchfield was smoke tested on 4/15/2019, 6/11/19, 6/12/19,
1/31/20, and 2/5/20. The test conducted on 2/5/20 revealed a positive storm drain connection on
private property. The positive storm drain connection was removed on 2/7/20. Despite our
diligent efforts, however, we still have I&I, as does every wastewater collection system.
The City would respectfully request that a civil penalty not be assessed for the violations in
question, since the violations were due to heavy rain, City staff reacted immediately to lessen the
impact of the violations, and City staff works diligently to eliminate I&I from its collection
system. If you have any questions or require additional information, please contact me at 828-
652-4224 or W WTP Superintendent Tim Horton at 828-652-8843. Thank you in advance for
your time and consideration.
Sincerely,
/BramZ
JSikes
Public Works Director
cc: Bob Boyette, City Manager
Tim Horton, W WTP Superintendent