WQ0039473_NOV-2023-DV-0203_20230602

NC Dept of Hivironmental Qn„
0 JUN - 2 2023
Raleigh Regional Of; n
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NORTH C\r. 01 INN
May 26, 2023
EMAIL and CERTIFIED MAIL
Mr. Kevin Fowler
NCDEQ Division of Water Resources - RRO
5800 Barrett Drive
Raleigh, NC 27609
SUBJECT: NOV-2023-DV-0203
Town of Hillsborough Collection System
Permit No. WQC500077
Dear Mr. Fowler,
This letter is in response to the Notice of Violation (NOV-2023-DV-0203) regarding the Sanitary Sewer
Overflow (SSO, No. 202300654) that occurred on 04/10/2023. We received a call from our Water
Treatment Plant around 2:00 pm stating that a customer, while on a walk around the pond on her
property, suspected a sewer leak due to odor and wet area on her property.
Staff immediately mobilized onsite and found the location described by the caller. Knowing that there is
no gravity sewer in the immediate area we determined discharge to be from our Shelton Ct. pumping
station force main. The station, built by a developer in the 80s and subsequently donated to the town,
which receives flow from only a handful of duplex condominiums was swiftly shut off ending the SSO at
2:30 pm on 04/10/2023. A crew was then called in to begin excavation/repair of force main and to
monitor the station to maintain the wet well level as needed. The 2-inch force main was excavated
revealing a 1.5" pipe split with no noticeable culprit allowing a determination of the actual cause of
damage. The section was cut out and replaced with new pipe and couplings. Contaminated topsoil was
removed and properly disposed after the repair was completed and the entire area (maintaining a
buffer from the edge of private pond) was then limed and covered in straw. Multiple water samples
were taken from the private pond that sewer had discharged into and tested at our Wastewater
Treatment Plant over multiple days to ensure ammonia was not above tolerable levels. There was no
evidence of aquatic harm. A press release was prepared and issued by our communications team as
required by G.S. 143-215.1.
101 I:. OrangeSt.. Hillsborough. \'c 27278
919-732 1270 www.hillsbunmAinc.g,w I rvHillsboruughC inv

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The volume was estimated by assuming the split occurred up to a week prior and what was seen at the
site. We utilized pump run times over those days to calculate the total pumped and a portion that would
have been pushed through the split pipe section. It may be overly conservative.
Since this 550 occurred, the force main has been moved to our high priority list and the area has been
inspected periodically. We believe this was an unpredictable material failure outside of our prevention
that was promptly remediated upon first knowledge.
The town has greatly reduced SSOs over the past decade and we take pride in SSO prevention with our
program. We request that no civil penalty be assessed for this unavoidable incident. If there is additional
information we can provide, please advise. We also request that future notices or correspondence
regarding the collection system be copied to our Utilities Director, Mane Strandwitz, at the same
permittee address as notices to our town manager may be delayed in receipt.
Sincerer X
Thomas Smith
Collection System Back-up Operator in Responsible Charge
Utility Mechanic III
Cc: Marie Strandwitz, Utilities Director
File