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HomeMy WebLinkAboutWQCS00009_NOV Response_20180508WSACC f ISO 140012015 + NC Star Public Sector 4 OHSAS 18001,2007 May 8, 2018 CERTIFIED MAIL REQUEST RETURN RECEIPT REQUESTED W. Corey Basinger, Regional Supervisor Water Quality Regional Operations Section Division of Water Resources, NCDEQ MRO 610 East Center Avenue, Suite 301 Mooresville. NC 28115 WATER & SEWER AUTHORITY OF CABARRUS COUNTY Administrative Offices 232 Davidson Hwy, Concord, NC 28027 704.786.1783 4 704.795.1564 Fax Rocky River Regional WWTP 6400 Breezy Lane, Concord, NC 28025 704.788.4164 ♦ 704.786.1967 Fax www.wsacc.org RE0EIV90/N0bg1q k,,, MAY 112018 WQROS WORESVILLE REGIONAL OFF109 SUBJECT: NOTICE OF VIOLATION & INTENT TO ISSUE CIVIL PENALTY (NOV-2018-DV-0114) Sanitary Sewer Overflows — March 2018 WSACC Collection System Permit WQCS00009 Dear Mr. Basinger: WSACC is in receipt of the subject notice regarding the sanitary sewer overflow located near 1175 Crosspointe Drive, NE, in Concord (NC). Following is a summary of background information and the steps taken as a result of the overflow. 1) The area surrounding the gravity interceptor that experienced the washout and failure has experienced significant commercial growth over the past 10 to 15 years. This development has resulted in increased runoff along with changes to the path that runoff takes across WSACC's interceptor. As you can see in the attached aerial photos, the drainage path that storm water flows has changed significantly over the 2009 to 2015 period. 2) The changes to the drainage path resulted in WSACC observing the washing out of its sewer lines contained within its right of way. In 2010, we hired a contractor to stabilize and install large diameter rip rap in the compromised right of way area. WSACC staff continued to monitor this site along with others that have been known to show the potential to washout within our system over the years following large rain events. 3) WSACC staff discovered the washout and subsequent spill while in the process of installing area velocity sewer meters within WSACC's lines to monitor inflow and infiltration. Once the damaged pipe was discovered WSACC quickly moved to plug the line and then pump the flow through our parallel gravity interceptor thus minimizing the quantity of flow that was spilled. 4) A contractor was hired to make the necessary repairs to the interceptor and stabilize the ROW with large diameter rip rap. The contractor also installed a 30" culvert to allow the drainage channel to return to the path the flow had followed in 2009. WSACC will continue to monitor this area along with other areas throughout its system. WSACC will also continue to be proactive in protecting its facilities and take all steps possible to prevent future spills. If you have any questions or concerns, I may be reached at 704-788-4164, X-113 or via email at cvoncannon(wsacc.ora. Sincerely, aA—�- Chad VonCannon, PE Assistant Engineering Director CV/blc cc: Tim Kiser (WSACC) Wayne Lyles (WSACC) Beverly Metcalf (WSACC) Attachment — Aerial Photos of Cold Water Creek 18" Interceptor Sewer