San Angelo flooding caused 1.6-million-gallon sewage spill

SAN ANGELO, Texas (KXAN) – Massive rainfall and floodwaters tore through the Texas Hill Country on July 4, taking over 135 lives, destroying homes, and, amid the chaos, causing a 1.6 million-gallon sewage spill near San Angelo.

The 15 inches of rain that fell around San Angelo on Independence Day overwhelmed and damaged part of the city’s wastewater system, causing the sewage to discharge into the Concho River, which connects to the Colorado River and ultimately reaches Central Texas and Austin.

San Angelo also had a smaller 67,000-gallon spill caused by the floods on July 4. The San Angelo incidents were the only significant wastewater spills caused by floods reported to the Texas Commission on Environmental Quality over the Independence Day weekend. Utilities are required to notify the TCEQ of those spills.

“Risk from this discharge was greatly minimized due to the floodwater dilution and extremely high river flow,” said City of San Angelo spokesperson Lorelei Day.

Aside from San Angelo’s wastewater spill, Natalie Exum, assistant professor of environmental health and engineering at the Johns Hopkins Bloomberg School of Public Health, said the extreme Central Texas flooding raises concerns about what other contaminants the storm could have pushed into the river. Fuels or other hazardous chemicals, for example, could have gotten mixed into the water, she said.

After flooding and sewage overflow, acute gastrointestinal episodes are a common problem. Generally, utilities should be able to treat and remove contaminants, and people getting their drinking water piped from a regulated water treatment facility are going to be fine.

“What other things are in these spills that are going to be potentially harmful to health?” she said, speaking broadly about potential contamination across Central Texas that hasn’t been reported.

Were highly contaminated sites potentially washed out, she asked, and to what extent would agencies test water to find out?

Routine testing

Relevant agencies contacted by KXAN did not indicate there has been additional testing — beyond what is already required and typically done — to determine exactly how flood waters may have contaminated rivers and lakes.

Scott McWilliams, general manager of the Upper Colorado River Authority, said he was aware of the sewage spill. With the amount of rain the area received, “there's nothing that's designed to handle that kind of volume of water coming down,” he said.

The UCRA oversees the Concho and Colorado River watershed surrounding San Angelo. Both those rivers flow into Lake O.H. Ivie. From there, the Colorado River runs through multiple counties to Central Texas and the Highland Lakes.

About 85,000 acre-feet of storm water flowed into O.H. Ivie from the storm. The sewage spill was about five acre-feet, McWilliams said. That means less than .006% of the storm water in the lake was from the spill, he said. You can see O.H. Ivie's lake level changes here.

“At that small a percentage, you'd never be able to do any testing that you would notice it,” McWilliams said. He said TCEQ’s Region 8 team oversees environmental regulation of that area. In terms of water testing, McWilliams said his office would stick to its quarterly water quality testing conducted at 48 sites on the Concho, its tributaries, and the Colorado River above OH Ivie. UCRA would also soon begin aquatic life monitoring – all part of its work on the Clean Rivers Program of Texas.

“We do standard chemical testing with phosphorus, and we do E. coli testing for bacteria, not at every single site, but at most of the sites,” McWilliams said.

UCRA is not testing for hazardous chemicals in this case, he said. The agency’s standard testing would likely indicate if something major is amiss. For example, if the pH levels or salinity drastically changed, that could prompt further investigation.

LCRA flood response

The Lower Colorado River Authority – a vastly larger agency than the UCRA – regulates the lower section of the Colorado River and its tributaries through Central Texas.

LCRA “routinely monitors water quality throughout the lower Colorado River basin.” As of July 23, the water quality is “generally good,” said LCRA spokesperson Clara Tuma. Bacteria levels typically go up after floods and remain there for at least two weeks, depending on storm severity, she said.

“LCRA does not conduct water quality tests immediately after a flood because the results would be good only for the specific location at the time the test was conducted,” Tuma said by email. With rapidly changing conditions, “the results would be outdated quickly and would not be helpful in making decisions about whether to enter the water.”

Regarding hazardous chemicals and pollutants, she said retail water utilities would test for those and remove them before providing water to users.

Similar to the LCRA, a spokesperson for the TCEQ said the agency “does not typically sample flood waters because we presume that the waters would be contaminated.”

TCEQ pointed to its fact sheet, saying flooding can take “bacteria, nutrients, oil and grease, and other contaminants” into waterways. Floodwaters pose various risks, including infections, physical injuries from displaced objects and “exposure to chemical hazards.”

The LCRA’s water quality testing data is available online, and KXAN has requested the latest data from the River Authority.