HomeMy WebLinkAboutWQCS00057_NOI_NOV2020DV0207_Response_#2_20200514of
tv uv - VN - 0a o'j
•
City of Thomasville
Thomasville, North Carolina 27360
Utilities Department
Lon T. Snider
Regional Supervisor
WQROS, WSRO, DWQ, NCDEQ
450 W. Hanes Mill Road, Suite 300
Winston-Salem, NC 27105
14 May 2020
RE: Intent to Enforce Letter Response
Incident Number 202000167
Dear Mr. Snider,
In response to the letter of Intent to Enforce of 07 May 2020 the City of Thomasville asks that
the following be taken into consideration:
Regarding incident # 202000167: CIPP lining of the Hanks Branch outfall main line had been
largely completed as part of the Hank's Branch Phase 1 Rehabilitation when this incident occurred. This
rehabilitation work has served not only to reduce infiltration, but also to reduce exfiltration from the
main Hanks Branch Outfall pipe. Upstream of the CIPP lined outfall pipe rainfall runoff entered the
collection system through multiple means such as leaky pipe joints, broken taps and cleanouts, and
leaking manholes during an extreme precipitation event. The increased volume of the main outfall for
transmitting flow to the pump station (due to the cleaning which removed a large amount of debris)
combined with the better sealed system led to reduced exfiltration of the I&I water and overwhelmed
the pump station.
Enclosed are 2 charts reflecting hourly rainfall totals as measured at 2 monitoring points
upstream of the event site. Both charts reflect a large amount of precipitation between 17:00 and
23:00 on the date of the event, which occurred between 20:30 and 23:30. Also reflected is significant
rainfall between the hours of 05:00 and 08:00 which served to "pre-soak" the soils, leaving the ground
without the ability to absorb much of the precipitation later in the day, and leading to a large amount of
runoff and inflow.
Of the total volume of wastewater spilled much of the water was rain water, and there were no
known impacts to public health, fish kills, or recreational area closures as a result. There is a second
phase of this project planned that has been under reviewed by DWR and DWI staff for quite some time
now, delaying its eventual implementation. Phase 2 of the Hank's Branch Outfall Rehabilitation will
address several upstream sections of laterals that discharge into the Hanks Branch main outfall that
have I&I issues by a combination of pipe replacement and CIPP lining where appropriate. It is
anticipated that Hanks Branch Outfall Phase 2 will have the desired effect of reducing I&I and thus
reducing the chances of further overflows at the Northside pump station.
The City of Thomasville asks that the circumstances surrounding this event, the lack of
demonstrable environmental impact, as well as the ongoing efforts to upgrade all aspects of the
sanitary sewer collection system be taken into account with any enforcement action considered.
Sincerely, P Morgan Huffman
Public Services Director
City of Thomasville
CC: Kelly raver 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 (°F)
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
1/24/2020 17:00
0.15 0
1/24/2020 18:00
0.20 0
1/24/2020 19:00
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