WQCS00057_NOI_NOV2020DV0207_Response_#1_20200514

o� THOfI9S
.Y i
.� City of Thomasville
°°" "' Thomasville, North Carolina 27360
CAROB
Lon T.Snider
Regional Supervisor
WQROS, WSRO, DWR, NCDEQ
450 W. Hanes Mill Road, Suite 300
Winston-Salem, NC 27105
RE: Notice of Intent Letter Response
Incident Number 202000168
Dear Mr. Snider,
Wl�(,5�00 51
Nod-'aoa�- a4 - 0�.01
Utilities Department
14 May 2020
In response to the letter of Notice of Intent of 07 May 2020 the City of Thomasville asks that
the following be taken into consideration:
Regarding incident # 202000168: Rainfall on the date of the event was over 1.5" throughout the
area as reflected in the attached graph of precipitation throughout January, 2020. We are aware of and
have continued to pursue identification and remediation of I&I issues on the collection system leading
into the Rains Road pump station. This incident occurred after rain fell for a second period on already
saturated ground. As reflected on the enclosed tables of rainfall amounts measured at two locations,
one upstream of and one in the vicinity of the Rains Road pump station, there was precipitation earlier
in the day on the date of the event that served to pre -saturate the ground reducing the ability of the
ground to absorb the large amount of precipitation that fell later in the day. Given the saturation
already evident when the additional 1.1+ inches of rain fell between 17:00 and 00:00 inflow entered the
already full collection system and caused this overflow. Given the duration of the event it is also
probable that infiltration from the by then completely saturated ground continued to enter the
collection system and extend the event.
First, a recap of information previously submitted, but still relevant:
We have been and will continue to pursue identification and remediation of the sources of I&I
in a logical manner. There are two main outfalls that lead into this station, Hunts Fork Creek and Hasty
Creek.
KRG Utilities has completed cleaning and video inspection of —9,030 linear -feet of 18" and 21"
RCP pipe on the Hunts Fork Creek Outfall, one of the two main outfalls that lead into this station, at a
cost of over $80,000. Overall, the Hunts Fork Creek Outfall pipe appears to be in very good condition
for a 60-year-old concrete pipe carrying sewer. The only sources of inflow found thus far are located at
the few direct taps into this line. These will be repaired.
KRG Utilities has also completed cleaning and video inspection of the main Hasty Creek Outfall
line, 15,375 linear feet of 8" to 15" VC and DI line at a cost of $57,821.00. There are 6 segments of this
line that will require plugging and re -inspecting to complete inspection due to the high water levels
encountered. Several small sources of infiltration were identified and remediation options are being
explored.
Smoke testing of 108,447 linear -feet of these outfalls and 547 manholes leading into this
station was completed by Consulting Engineering firm Alley Williams Carmen and King and resulted in
the location and repair of 122 cleanouts. Twenty-three manholes, mostly located on the lower Hasty
Creek outfall were identified in the report as possible sources of I&I in need of attention. Manhole

rehabilitations will be scheduled pending receipt of results of additional cleaning and video inspection
currently taking place on the Hasty Creek Outfall. The entire main Hasty Creek outfall has been cleaned
and video inspected by KRG Utilities, but there were several segments of the lower Hasty Creek outfall
that could not be video inspected properly due to the volume of water in the pipes and are currently
scheduled to be plugged upstream and re -inspected by video. These segments have still not been re-
inspected due to the continued high volume of water in the pipes — presumably due to the high amount
of precipitation we have experienced and high ground water tables. Pending the results of these
inspections the determination will be made as to if any and if so how much of the lower Hasty Creek
outfall needs rehabilitation by relining of pipes and manhole rehabilitation.
One of the sub -basins that feed into the Hasty Creek outfall has been cleaned and video
inspected and only one section of damaged pipe has been found. This pipe section, while damaged, did
not appear to be an active source of inflow, but it will be repaired now that we are aware of it. Repair
of this section of pipe will require the removal of a concrete driveway and is being scheduled.
The entire main line of the Hunt's Fork Creek outfall was cleaned and video inspected previous
to investigation of the Hasty Creek outfall due to its age (1969) and material composition (RCP) and was
found to be in surprisingly good shape. The only sources of I&I located were three or four break-in
service taps that had inflow at the connection. Contractors are currently pricing out the repair of these
service taps.
Continuing information:
Alley Williams Carmen and King is still working on a flow study of the entirety of the drainage
areas that discharge into both the Rains Road Pump Station and the next downstream pump station,
Northside Pump Station. Preliminary results were expected near the end of February/beginning of
March to help us narrow down whether the causative problem is more closely aligned with excessive
I&I or undersized pump stations to meet the existing sewershed area demand, but the as of the date of
this letter the results have not been finalized.
New information:
The City of Thomasville has scheduled the installation of flow meters on the discharge force
mains at our four largest pump stations, Rains Road being one. The flow meters are scheduled to be
installed the week of May 18, 2020 and it is anticipated that having verifiable, live flow data will aid in
determining the causative factors in the repeated S5O's at this location.
The City of Thomasville has spent, and will continue to spend, millions of dollars to protect the
environment by identifying and correcting deficiencies in the collection system. There were no known
impacts to public health, fish kills, or recreational area closures as a result of this spill.
The City of Thomasville asks that the ongoing efforts and expenditures to identify and
remediate the sources of I&I in the sanitary sewer collection system be taken into account with any
enforcement actions considered.
Sincerely, ;�// P, IL
CC: Kelly Craver
Morgan Huffman
Utilities Director
City of Thomasville
336-475-4220

Ivey Creek PS
Rainfall from 1/1/2020to 1/27/2020
Device Time Rainfall Amount (inches)
1/24/2020 0:00
0
1/24/2020 1:00
0
1/24/2020 2:00
0
1/24/2020 3:00
0
1/24/2020 4:00
0
1/24/2020 5:00
0.13
1/24/2020 6:00
0.10
1/24/2020 7:00
0.08
1/24/2020 8:00
0.05
1/24/2020 9:00
0.01
1/24/2020 10:00
0
1/24/2020 11:00
0
1/24/2020 12:00
0
1/24/2020 13:00
0
1/24/2020 14:00
0
1/24/2020 15:00
0
1/24/2020 16:00
0
1/24/2020 17:00
0.14
1/24/2020 18:00
0.15
1/24/2020 19:00
0.63
1/24/2020 20:00
0.10
1/24/2020 21:00
0.03
1/24/2020 22:00
0.06
1/24/2020 23:00
0.06
1/25/2020 0:00
0.01
1/25/2020 1:00
0
1/25/2020 2:00
0
1/25/2020 3:00
0
1/25/2020 4:00
0.01
Total:
1.56

Golf Course PS
Rainfall from 1/1/2020to 1/25/2020
Device Time Rainfall Amount (inches) Temperature (7)
1/24/2020 0:00
0 0
1/24/2020 1:00
0 0
1/24/2020 2:00
0 0
1/24/2020 3:00
0 0
1/24/2020 4:00
0.01 0
1/24/2020 5:00
0.11 0
1/24/2020 6:00
0.12 0
1/24/2020 7:00
0.09 0
1/24/2020 8:00
0.05 0
1/24/2020 9:00
0.01 0
1/24/2020 10:00
0 0
1/24/2020 11:00
0 0
1/24/2020 12:00
0 0
1/24/2020 13:00
0 0
1/24/2020 14:00
0 0
1/24/2020 15:00
0 0
1/24/2020 16:00
0 0
1/24/202017:00
0.15 0
1/24/202018:00
0.20 0
1/24/202019:00
0.52 0
1/24/2020 20:00
0.09 0
1/24/2020 21:00
0.04 0
1/24/2020 22:00
0.05 0
1/24/2020 23:00
0.05 0
Total:
1.49