WQCS00004_NOV-2020-DV-0425 Response_20200925

Metropolitan Sewerage District
OF BUNCOMBE COUNTY, NORTH CAROLINA
G. Landon Davidson, P.G., Regional Supervisor
Water Quality Regional Operations Section
Asheville Regional Office
Division of Water Resources, NCDEQ
Subject: NOTICE OF VIOLATION
Tracking Number: NOV-2020-DV-0425
510 Riverview Drive
Sanitary Overflow — August 31, 2020
Permit No. WQCS00004
Metropolitan Sewerage District of Buncombe County
Mr. Davidson,
September 21, 2020
PCIF4
SEP 2 51020
Water Quality Regional Operations
Asheville Regional Office
In response to the above -mentioned notice of violation for the SSO located at 510 Riverview
Drive, MSD would like to provide you with information about the cause of overflow and
upcoming projects that are in MSD's capital improvement program that will address this aging
infrastructure.
Carrier Bridge pump station control panel lost power due to the uninterruptible power supply
(UPS) failing. Crews were notified of the issue and had the pumps back online within 20
minutes.
Here is the list of corrective actions that have been implemented to ensure the incident at
Carrier Bridge does not occur again.
1. Currently, Carrier Bridge PS communicates to MSD SCADA by DSL service, with a Cellular
Modem as a backup communication in an occurrence of a DSL communication failure. We are
improving the communication testing of the DSL and Cell Modem redundancy by performing a
Cell Modem communication test every 15 minutes, while DSL communication is active. When
four consecutive cell modem communication tests fail, a cell modem failure will be reported to
SCADA personnel. When a DSL failure occurs, the failure will be reported to SCADA
personnel. In the event of a DSL and Cell Modem communication failure, a station
communication alarm will be triggered and immediately be reported to On Call Personnel.
2. Modifications made to the RTU/Pump Control Panel equipment for automatic failover from
uninterruptible power supply (UPS) AC power to Utility AC power.
3. An annual preventive maintenance schedule has been created in our Cityworks software to
replace the batteries in the UPS annually.
4. Implementation of a monthly UPS test to ensure proper operation of UPS equipment.

The overflow occurred just upstream of Carrier Bridge pump station. All residuals were
removed from the area and lime and gravel were placed at the area of spill. At the time of the
overflow the river flow was running at 89.4 million gallons per hour. The Sanitary Sewer
Overflow accounted for Tess than 0.3% of the total river flow for the short duration of the
overflow.
Carrier Bridge Pump Station Replacement Project # 2019045 is currently in design with
CDM. Planned construction to begin in Spring 2022 at an estimated construction cost of $35
million. MSD has acquired the land adjacent to the existing pump station for this project.
MSD has invested in excess of $400 million into the collection system for Capital
Replacement Projects since consolidation in 1990. These projects have had huge impacts to
the reduction of SSO's in the South French Broad River Corridor with a 91% reduction in SSO's
since 1999. MSD has budgeted $332.4 million in Capital Improvements over the next 10 years
with $66 million going directly to this area of the South French Broad River Corridor.
If you have any additional questions regarding the overflow or any of the above -mentioned
projects, please give me a call.
Thanks,
C. Kenneth Stines
Division Director
System Services Division
MSD of Buncombe County, NC
[e-mail]
[phone]
cc: Tom Hartye
-Protecting Our Natural Resources~
2028 Riverside Drive ASHEVILLE, NORTH CAROLINA 28804 TELEPHONE: [phone] FAX: [phone] WEBSITE: www.msdbc.org

Written response for:
Notice of Violation & Intent to Issue Civil Penalty
Tracking Number: NOV-2020-DV-0425
Sanitary Sewer Overflows — August 2020
Collection System Permit No. WQCS00004
Metropolitan Sewerage District of Buncombe County
ncident #: 202002520 510 Riverview Drive
SEP 2 5 2020
Water Quality Region; 4E_
Asheville Regional Office
I confirm that I have received written response for the
SSO's listed above:
(Name)
09-75-zoze
(Date)