City working to replace collapsed sewer main

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San Angelo, TX (KLST/KSAN) – Following the Dec. 9 collapse of a 24-inch sewer main underneath Houston Harte Expressway, repairs to replace the line are underway.

The City of San Angelo teamed up with Darnell Construction to mobilize a bypass pumping system out of Fort Worth for a formalized and more permanent solution while the repairs to the line are performed. This will contain the sewer in a system from the north side of the loop to the south side, and no longer use the storm drain to convey sewer.

After the collapse, the City diverted approximately 1,050,000 gallons of sewage from storm drains back into the sewer system, however an estimated 450,000 gallons of sewage made its way into the Concho River.

Shortly after the formal pumping system was installed, crews began excavation work on the line. The goal is to be able to pull new pipe through the existing line, but the line must first be cleaned in order to do that.

“Pulling new pipe through the existing line is not a guarantee at this point,” said Water Utilities Director Allison Strube. “But as we clean out the existing line, we will have much more confidence to provide a definitive answer and ultimately the time frame for completion.”

City crews worked on cleanup of the initial sewer spill and assisting the contractor as necessary for the repairs. The access road on both sides of the loop will remain closed at this time, as will the Oaks Street exit.

With the cleaning that began Thursday, Dec. 12, the City will have a better idea on time frame as the process progresses. The contractor will be working on Saturdays and will let his crews rest on Sundays. Aside from that, they will stay dedicated to the project to completion.

When the collapse was discovered, the San Angelo Water Quality Department quickly dispatched laboratory technicians to the area where the release entered the Concho River to collect samples and determine if there could be an adverse impact to the river water quality.

As of Friday, Dec. 13, dissolved oxygen levels and biochemical testing at the point of entry, upstream and downstream have indicated very little detectable adverse effects. Dissolved oxygen levels at all three sample locations indicated DO readings above 9 mg/L, which are very normal conditions for this time of the year.

Strube said the affected areas are downstream of the kayaking events taking place this weekend.

Repairs to replace the sewer main are estimated to be completed in approximately one month.

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