WQCS00060_NOV-2020-DV-0410 Response_20200929

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DEPARTMENT OF PUBLIC UTILITIES
PO BOX 2263
SMITHFIELD, NC 27577
[phone]
September 29, 2020
Mr. Scott Vinson
Raleigh Regional Office
NCDEQ DWR
1628 Mail Service Center
Raleigh, NC 27699-1628
Re: Response to NOV-2020-DV-0410
Permit No. WQCS00060 - Johnston County Collection System
Dear Mr. Vinson:
NC Dept of Environmental Qu;jl;jx
OCT -- 6 2o20
Raleigh Rcg1011al Office
In response to NOV-2020-DV-0410, the County offers the following information:
On August 31, 2020, Johnston County received rainfall during the day and much of the night. Rainfall
amounts throughout the area varied. However, rainfall in the Four Oaks/South Smithfield area totaled
over 10" in less than 24 hours. After the event, Johnston County Emergency Management staff
contacted the National Weather Service to determine if there was an official rainfall total for the area.
The National Weather Service reported that there is no official rain gauge in the area, but confirmed the
area was in a "bullseye" for rainfall. Attached maps from various media, indicate the area received in
excess of 10" and up to 14.9" of rainfall. The exceptionally intensive rainfall event caused significant
problems throughout the area, including road flooding, road wash -outs, water main damage, power
outages and flooding of structures. Tragically, two children lost their lives when a road washed out and
swept their car away on Galilee Road. After multiple failed attempts, rescuers were unable to save the
children and were themselves caught in the floodwaters. This storm event was an act of nature, and
this localized area experienced more rainfall (in volume and intensity) than received in recent
hurricanes. According to Brad Panovich (Chief Meteorologist for WCNC-TV), the event exceeded a 500
year storm and approached a 1,000 year storm event for the area. Please see the enclosed pictures of
damage and media rainfall reports.
The SSOs referenced in NOV-2020-DV-0410 were caused by severe natural conditions, and were
exceptional and unintentional.
Incident Numbers: 202002530, 202002531, 202002532, 202002533 and 2020002534:
o The spills were caused by severe natural conditions and were exceptional and
unintentional.
o The spills were caused by infiltration and inflow of rainwater from the excessive and
exceptionally intensive rainfall event into the wastewater collection system.
o The County utilized pumper trucks to minimize the overflows to the extent possible.
o Due to flash flooding, some of these sites were temporarily inaccessible.

Page 2
Mr. Vinson
September 29, 2020
Additional Information for Incident Number 202002534:
o The facility located at 400 Fawn Brook Drive, Four Oaks is where the County receives
wastewater from the Town of Four Oaks collection system and transmits flow to the
County's system for treatment. The spill was caused by infiltration and inflow of
rainwater from the exceptionally intensive rainfall event into the Town of Four Oaks
wastewater collection system.
o The average daily flow for July 2019 through June 2020 received from the Town of Four
Oaks at this site was 0.096 MGD. However, the County received more than 0.819 MGD
over the 24-hour period associated with the excessive rainfall event, which is over 8.5
times the average daily flow received from the Town of Four Oaks at this site. The site
has 300,000 gallons of flow equalization for storage, and the storage capacity is not
utilized on a typical day.
o The County utilized all means necessary to equalize the flow received and pump to the
downstream facility in order to minimize the SSO.
Johnston County works aggressively to prevent sanitary sewer overflows and help protect the waters of
our area. Preventative measures include the following:
• Extensive staff training ensures staff is prepared for system operation and response during
storm events when the system could be at risk due to infiltration.
• All wastewater pump station sites are equipped with SCADA to provide real-time wetwell level
information, pump status and generator status.
• Staff use laptops to log into the SCADA system and monitor system operation from any location.
• Furthermore, staff is on -call and prepared to respond to any event.
• Staff visits sites during the storm events to make any necessary modifications/adjustments to
system operations and to direct septic pumper and/or vacuum trucks to prevent spills, if
necessary.
• On -site generator back-up power is available at all County wastewater pump station sites, and
staff conducts weekly generator testing.
• The County maintains an in-house supply of repair materials for all pipe sizes and many
electrical components and implements a detailed protocol for emergency response.
• The County maintains a close working relationship with several local contractors who provide
emergency response repairs, as needed.
Johnston County takes seriously our responsibility to protect public health and the environment and
strives to prevent sewer overflows. Please contact me at [phone] or
[e-mail] if you have any questions or need additional information regarding
this issue.
Sincerely,
LVW4&� G. U.Nm
Chandra C. Farmer, PE
Director of Utilities
cc: Rick J. Hester, County Manager
Eric Narron, Johnston County
Mitchell Hayes, Raleigh Regional Office
Enclosures

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