The Texas Commission on Environmental Quality (TCEQ) regulations (30TAC 319) require that municipalities report wastewater collection system overflows to the local media and the County Judge when overflows exceed 100,000 gallons. On Sunday, Sept. 30, 2018, TCEQ received a call from a fisherman reporting dead fish and sewage smell near where Pecan Creek enters Lake Lewisville. Data from monitors upstream and downstream from the Pecan Creek Wastewater Treatment Plant did not indicate any problems at the plant discharge site. Denton staff then began monitoring water quality in Pecan Creek via boat, starting at Lake Lewisville and moving upstream.
The sewer overflow was eventually found in an isolated area of Pecan Creek south of the treatment plant, and was caused by a break in a large sewer line. The recent substantial rains caused slope failure in Pecan Creek around a bend in the creek, resulting in a large amount of pressure on the line, which ultimately caused the line to break. As soon as the break was discovered, Denton staff mobilized to stop the overflow and stabilize the failed slope area. Equipment and personnel from multiple departments worked non-stop from Monday afternoon into Tuesday morning to remove and stabilize the soil in the area, plug the broken sewer line, and reroute the sewage to the plant. The overflow was stopped on Monday evening, and work continues to stabilize the failed slope, and repair the broken sewer line. City staff also placed aeration devices in the creek to help raise oxygen levels in the water, and continues to monitor water quality.
TCEQ staff visited the site Tuesday morning to review the progress being made in remedying the overflow incident. While impossible to know the exact time of the release, it is estimated that the release started on Sept. 29 at approximately 3 p.m. and continued until Oct. 1 at 11:30 p.m. The estimated volume of the spill was 2,601,825 gallons of domestic sewage. Because the point of discharge is downstream of the intake point for Denton’s water supply, and is far removed from the intake points of other water suppliers, impacts to drinking water are highly unlikely. Monitoring information within the lake indicates that the sewage impact has dissipated rapidly once the water flowed out of Pecan Creek and into the lake.
Due to the length of time the overflow occurred, the fish kill, and areas of the Pecan Creek that are have been in contact with sewage, City of Denton recommends citizens avoid any contact with the creek, as well as abstain from any recreational use of the channel from downstream of the Pecan Creek Water Reclamation Plant to Lewisville Lake. If the public comes into contact with water or soil potentially affected by the spill, they should bathe and wash clothes thoroughly as soon as possible.
All notifications required by 30TAC 319 have been completed.
Contact: Dr. Kenneth Banks, (940) 349-7165, Kenneth.Banks@cityofdenton.com