Wastewater force main failure near I-35E and SH 121

The City of Lewisville is notifying the public of an unauthorized wastewater discharge that occurred following the failure of a 24-inch wastewater force main near the I-35E frontage road, just south of SH 121.

The failure was reported at about 5 p.m. Thursday, Sept. 24, and confirmed by 5:30 p.m. City crews and a utility repair contractor immediately mobilized to the site. Repairs were completed, and the discharge stopped at approximately 9:30 a.m. Friday, Sept. 25. The City's drinking water system was not affected.

The force main, a pressurized pipe in the City's wastewater collection system, carried domestic wastewater. The City estimates about 4 million gallons were released at a rate of about 3,500 gallons per minute. These figures are preliminary and will be updated as more information is reviewed.

The wastewater flowed a short distance over land before entering Timber Creek. Lewisville Environmental Compliance Services staff are monitoring the creek downstream and taking field measurements to determine the extent of the impact. The City has also notified the City of Carrollton, which is downstream.

Because the wastewater entered the waterway, recovery of the discharged volume is not considered practicable. With the force main repaired and the discharge stopped, City crews are performing aeration and disinfection of the affected area to the extent practicable. Environmental monitoring will continue, and the cause of the break is under evaluation.

Public health precautions
As required by the Texas Commission on Environmental Quality, the following precautions are recommended for areas potentially affected by the wastewater discharge:

• The public should avoid contact with waste material, soil or water in the area potentially affected by the discharge. If contact occurs, individuals should bathe and wash clothes thoroughly as soon as possible.
• Persons using private drinking-water supply wells located within one-half mile of the discharge site or within the potentially affected area should use only water that has been distilled or boiled at a rolling boil for at least one minute for all personal uses, including drinking, cooking, bathing and tooth brushing.
• Individuals with private water wells should have their well water tested and disinfected, if necessary, before discontinuing distillation or boiling.
• Persons who purchase water from a public water supply may contact their water supplier to determine whether the water is safe for personal use.The City has notified the Texas Commission on Environmental Quality and will submit required follow-up information, including the final estimated discharge volume, affected area, monitoring results, corrective actions, and other applicable documentation.

The City will continue monitoring conditions and will provide additional information as it becomes available.

Map description: Aerial map showing the Timber Creek area near the Interstate 35E and State Highway 121 interchange in Lewisville. Interstate 35E runs northwest to southeast through the center of the map, with State Highway 121 intersecting I-35E in the northwest portion of the map. Lake Vista Drive is shown west of I-35E.

A green arrow identifies the break location and entry point to Timber Creek on the northeast side of I-35E, just southeast of the I-35E and State Highway 121 interchange. Timber Creek continues generally southeast through a wooded area on the northeast side of I-35E. A second green arrow identifies where Timber Creek meets the Elm Fork of the Trinity River, southeast of the break location and near the highway interchange shown in the lower-right portion of the map.

A blue outline identifies additional areas surrounding the creek and extending on both sides of I-35E.