WQCS00005_NOV-2023-DV-0362_20231102

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WATER MANAGEMENT
CITY OF DURHAM
City of Durham
Department of Water Management
1600 Mist Lake Drive
Durham, NC 27704
919-560-4344
October 27, 2023
Mr. Scott Vinson, Regional Supervisor
Water Quality Regional Operations Section
Raleigh Regional Office
NCDEQ, Division of Water Resources
3800 Barrett Drive
Raleigh, NC 27609
Subject: NOV-2023-DV-0362 Permit No. WQCS00005
Dated: October 10, 2023; Received: October 19, 2023
City of Durham Collection System, Durham County
Dear Mr. Vinson,
NOV 2 - 2023
On October 19, 2023, the City of Durham Department of Water Management (DWM) received the above
referenced Notice of Violation and Intent to Issue Civil Penalty. As graciously requested in the letter, the following
evidence and justification demonstrates that these events were exceptional, unintentional, temporary, and
beyond reasonable control of the utility, and that DWM undertook significant costs to mitigate their impact.
Further, it demonstrates DWM's strong commitment to and investment in preventing and mitigating sanitary
sewer overflows (SSOs). All conditions of the City's Collection System permit are met by the Department, including
system cleaning, site visits, inspections, and easement maintenance.
As such, we respectfully request that no civil penalties be assessed for the SSOs that occurred in the City's sewer
collection system between September 1, 2023, and September 30, 2023.
Incident #202301326 - 2534 Durham Chapel Hill Boulevard - September 6, 2023, 7:18 AM
On September 6, 2023, at 7:18 AM, an overflow occurred near 2534 Durham Chapel Hill Boulevard releasing an
estimated 1,905 gallons of wastewater into a tributary of Third Fork Creek. Crews discovered that non -woven
materials were the cause of the blockage and used JetVac truck to successfully clear the line. After assessing the
extent of the spill, crews dammed the downstream creek with sandbags, set up a 4-inch pump to pump the
untreated wastewater back into the collection system, and flushed the area using a nearby hydrant (dechlorinated
water). Crews then used a JetVac truck to clean the three upstream and three downstream pipe reaches to ensure
the pipes were clear.

The City's Stormwater Services Division responded and conducted ammonia testing to help determine the spill's
extent and advise the Department when the site returned to normal conditions. No immediately visible adverse
environmental impacts or hazards to persons or property were observed.
A new release was issued within a 24-hour window with pictures of the non -woven material along with a message
regarding sewer stewardship. This location has been placed on a hot spot program for regular follow-up by City
staff.
The cost to remediate this spill was $7,756.64.
Incident #202301342 — 624 Homeland Avenue — September 11, 202311:03 AM
On September 11, 2023, at 11:03 AM, an overflow occurred near 624 Homeland Avenue releasing an estimated
2,585 gallons of wastewater into a tributary of Third Fork Creek. Crews discovered that pipe damage was the cause
of the blockage. After assessing the extent of the spill, crews dammed the downstream creek with sandbags, set
up a 4-inch pump to pump the untreated wastewater back into the collection system, and flushed the area using a
nearby hydrant (dechlorinated water). Crews then used a JetVac truck to clean the three upstream and three
downstream pipe reaches to ensure the pipes were clear.
The City's Stormwater Services Division responded and conducted ammonia testing to help determine the spill's
extent and advise the Department when the site returned to normal conditions. No immediately visible adverse
environmental impacts or hazards to persons or property were observed.
A new release was issued within a 24-hour window. The cost to remediate the initial impact of this spill was
$5,099.38.
The damage occurred to a segment of pipe for which there were already plans underway to replace it. At the time
of the break, design and permitting were nearing completion for this project with a planned construction start date
of January 2024 and a cost of $856,000. After the break occurred, the City accelerated and expanded the scope of
this project for an additional $407,000. We are planning to complete repair and/or replacement of this segment of
pipe by early November 2023. In the meantime, we are bypassing the area to mitigate any additional incidents.
Ongoing City -Wide Measures to Reduce the Occurrence of SSOs
DWM has several programs in place to prevent and reduce the occurrence of SSOs. DWM has implemented a
Collection System Management, Operations & Maintenance (CMOM) plan that expands and enhances its existing
programs.
System Flushing and Inspection: DWM routinely contracts cleaning, CCTV inspection, smoke testing, and
manhole inspections of portions of the sewer collection system. DWM completes the inspection of the
collection system systematically based on City defined geographical basins.
DWM ensures the requirements of the collection system permit are met by deploying City crews to clean at
least 10%of the collection system annually with a goal of exceeding the requirement by an additional two to
five percentage points each year. DWM measures the cleaning on a fiscal year basis starting July 1. In Fiscal
Year 2022, DWM cleaned 10.14%of the collection system. In Fiscal Year 2023, DWM cleaned 10.4%of the
collection system. As of September 30, 2023, approximately 1.75% of the City's collection system had been
cleaned by City staff and contractors for the Fiscal Year 2024.

Sewer Rehabilitation Program: DWM has an active Sewer Rehabilitation Program. The program includes flow
monitoring (25 permanent monitors), CCTV inspection, manhole inspection, easement mowing, field
inspections and investigations, point repairs, line replacement, root and grease abatement and cured -in -place
manhole and line rehabilitation.
There are four full-time equivalents (FTEs) employees dedicated to DWM's system rehabilitation programs in
the Utility Engineering Division of the Department. This workgroup handles flow monitoring and system data
management and contract preparation, administration, and inspections.
There are 21 FTEs in the City's Collections Systems Maintenance (CSM) workgroup in the Water and Sewer
Maintenance (WSM) Division of DWM. This group performs CCTV inspections, hydraulic cleaning activities,
mowing, manhole inspections, and manhole repairs. They respond to all reported concerns including blockages
and overflows. In addition, the CSM crews are supported by the Excavation Services workgroup of WSM who
perform identified point repairs, line replacements, and cured -in -place lining.
The Lift Station Maintenance Division (LSM) focuses on oversight and maintenance of the 61 lift stations
throughout the service area and the 136 air relief valves (ARVs) in the system. This workgroup of 21 FTEs
conducts required daily, weekly, monthly, and annual inspections and associated preventive maintenance
activities. In FY23, DWM spent about $22 million on Sewer Rehabilitation projects as a part of its Capital
Improvements Programs.
Fats. Oils, and Grease Program (FOG): The department's FOG education and outreach effort is conducted by
three FTEs. (Staff are shared between the Industrial Pretreatment, Septage and FOG Programs). In addition to
working with the Durham County Health Department, staff routinely inspect over 800 food service
establishments (FSEs) annually to ensure appropriate cleaning and maintenance of grease interceptors. Staff
participate in several community events, such as Earth Day, Center Fest and the Bimbe Festival, as well as
neighborhood meetings. Department staff deliver residential Fat Trappers to increase awareness of the proper
disposal methods for waste. DWM staff also conducts post-SSO follow-up education and enforcement as
necessary. DWM invests over $50,000 per year in advertising the proper disposal of FOG on television. Staff
post to the City's quarterly newsletter, the Durham Digest, along with multiple mentions in the City Manager's
Report known as City Connect, to reach a broad range of Durham residents.
Summary:
Based upon the documented information provided above regarding these incidents, DWM believes that these
SSO's were exceptional, unintentional, temporary, and caused by factors beyond the City and Department's
control. DWM actively manages, operates, and maintains its system in such a manner as to meet or exceed all the
requirements of the Collection System permit. As detailed above, DWM systematically inspects, flushes, and
rehabilitates its wastewater collection system. The Department also actively works to regulate and educate the
community regarding what should and should not be discharged into the City's sewer collection system.

The department staff welcomes the opportunity to meet with you and your staff to review our program and
discuss constructive ways to improve what we are already doing in the City of Durham. If you have any questions
or need any additional information, please do not hesitate to contact me at [phone] or via email at
[e-mail].
Sincerely,
DonaGre
Director
Attachments
C: Jason Robinson, DEQ— Water Quality Regional Operations Section, Raleigh Regional Office
Junior Mobley, Superintendent, Water & Sewer Maintenance
Mary Tiger, Assistant Director

WATER MANAGEMENT
CITY OF DURHAM
Date: November 2, 2023
To: Scott Vinson, Regional Supervisor
Water Quality Regional Operations Section
Raleigh Regional Office
NCDEQ, Division of Water Resources
3800 Barrett Drive
Raleigh, N.C. 27609
From: Don Greeley, P.E., P.L.S., Director
Subject: NOV-2023-DV-0362, Permit No. WQCS00005
City of Durham Collection System, Durham County
I received the document addressed to
(please print NAME)
Raleigh Regional Office on Thursday, November 2, 2023.
Signature Date
1600 Mist Lake Dr. Durham, NC 27704 919.560.4381 DurhamNC.gov Follow Us @CityofDurhamNC
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