WQCS00064_NOV-2020-DV-0182 Response_20200526

WATER RESOURCES DEI'AR'TMEN'r
CERTIFIED MAIL #7018 0680 0001 2233 8942
RETURN RECEll'T REQUESTED
May 26, 2020
Mr. Scott Vinson, Regional Supervisor
Water Quality Regional Operations Section
Raleigh Regional Office
Division of Water Resources, NCDEQ
1628 Mail Service Center
Raleigh, NC 27699-1628
Re: Response to NOV from Water Resources Dated April 29, 2020
Tracking Number: NOV-2020-DV-0182
Sanitary Sewer Overflows -February 2020
Incident Number 202000377
Collection System Permit No. WQCS00064
Apex Collection System
Town of Apex, NC
Wake County
Dear Mr. Vinson:
NC Dept ofEnvironmental Quality
MAY 29 2020
Raleigh Regional Ofiice
This letter is in response to the Notice of Violation (NOV) received on May 7, 2020, from the North
Carolina Department of Environmental Quality (NCDEQ), Division of Water Resources (DWR)
concerning sanitary sewer overflow (SSO) incident number 202000377. On February 6, 2020, the triangle
area was under a tornado watch and experienced several thunderstorms, downed trees, power outages and
localized heavy rainfall, with 4.5 inches measured at the Perry Farms pump station (PS). At approximately
4:30 pm that evening, Town staff received a high water level alert from our SCADA system, and mobilized
staff and equipment to the Perry Farms PS as soon as possible. Town staff implemented a pump and haul
operation utilizing the Town's combo trucks as well as a bypass pump to assist the existing station. At
approximately 6:05 pm, our operations could not keep pace with the significant inflow from this event as
sewer began to spill into an unnamed tributary to Little Branch. It was estimated that 40,000 gallons of
sewer was released during this incident.
The Perry Farms PS was constructed in 1994 with much of its tributary flow being permitted shortly after.
The contributing gravity sewer collection system is approximately 25 years in age and was likely designed
and constructed utilizing inferior standard specifications and inspection procedures as compared to the
requirements for today's newer development. In 2016, the Perry Farms PS experienced similar issues
during Hurricane Matthew. Subsequent field assessment activities revealed that manhole integrity and
Infi ltrationfi n flow ([/I) were likely contributors to the excess flow in this older collection system. Over the
ToWN or APEX
The Peak of Good Living
PO Box 250, Apex, NC 27502 1 (gig) 249-3400 1 www.apexnc.org

Mr. Scott Vinson
May 26, 2020
Page 2 of 2
past 4 years, Apex has identified and rehabilitated 19 sewer manholes contributory to Perry Farms PS that
were in poor condition and were significant Ill contributors. Additionally, various PS assessments and
drawdown tests have been completed to confirm the existing pumps are operating properly and in
accordance with the original design. Since Hurricane Matthew, the Town has not experienced any problems
with the Perry Farms PS until the February 6, 2020 rain event. Shortly after this recent SSO, Town staff
investigated all sewer outfalls in this basin and were able to identify additional manholes leading to excess
III. The Town annually dedicates funding through our CIA program to address I/1 concerns. Although
COVID-19 precautions have slowed our schedule, Apex will soon be contracting with a pump contractor
to complete a new assessment of the Perry Farms PS, and an engineering firm to perform various field
services to identify and rehab any additional 1/1 locations. These services will all be funded by our annually
dedicated Ill program.
We trust the information provided herein verifies that the SSO was not intentional, reflective of an extreme
Iocalized rain event, and that Town staff took all necessary precautions during extreme weather to reduce
impacts to public health, and the environment to the maximum extent practicable. The Town respectfully
asks that the information in this letter be taken into account when considering any further enforcement. If
you have any questions, please feel free to contact me at [phone] or michael.deaton(r7anexnc.org.
Sincerely,
Town of Apex
Michael S. Deaton, PE
Water Resources Director
cc: Mr. Mitchell Hayes, N.C. Water Quality Section
Mr. Drew Havens, Town Manager, Town of Apex
Mr. Marty Stone, Assistant Town Manager, Town of Apex
TOWN OF APEX
The Peak of Good Living
PO Box 25o, Apex, NC 27502 1 [phone] 1 www.apexnc.org