Drought, standing water leads to questions about water quality in South Texas rivers and lakes

Nueces River Authority tests water samples from more than 50 sites across area

The drought is gripping most of Texas and it's led to questions about the water quality in our rivers and lakes. KSAT's RJ Marquez spoke with the Nueces River Authority about testing water and the current state of some of the most visited swimming areas in South Texas.

SAN ANTONIO – The drought and heat are gripping South Texas and the lack of rain has led to questions about standing water in area lakes, rivers and popular swimming destinations.

“Warm water means it’s stagnant. We don’t recommend people swimming in stagnant waters,” said Sam Sugarek, dir. of water programs for Nueces River Authority - Coastal Bend Division. “If they’re in hot water, it kind of means the spring is not really flowing that well. I would avoid swimming in areas where the water is hot unless it’s a big body of water like a lake or something like that.”

The Nueces River Authority tests samples from more than 50 sites across the region.

“We generally encounter a lot of low flow conditions in the Nueces River Basin. In the Hill Country, in the headwaters, there’s usually pretty consistent flow coming from the springs,” said Sugarek.

Despite the lack of rain, Sugarek said the Nueces River Authority has not found harmful levels of bacteria in the water they have tested. That includes the Frio and Atascosa rivers.

“We haven’t identified any water quality concerns or impairments in the upper basin streams due to low flows,” said Sugarek. “It’s just pretty much good, quality water. There’s just not a whole lot of it.”

The Texas Commission on Environmental Quality has a threshold for dangerous bacteria in freshwater settings. In an emailed response, the TCEQ explained the testing process.

“For most streams, rivers, and lakes, the threshold is expressed as a geometric mean of 126 colony forming units (CFU) E. coli per 100 milliliters (mL). This is the presumed criteria for freshwater. A minimum of 20 samples is required to establish a geometric mean. In some cases, where TCEQ has established that there is an insignificant risk of ingestion by the public or recreation would not occur because of unsafe conditions, higher geometric mean thresholds have been approved.”

Sugarek said testing has not shown anything close to those numbers, but he cautions being safe around creeks that people do not visit often for recreational purposes.

“Smaller creeks that are kind of muddy bottomed aren’t the best place for swimming. Those usually do have higher bacteria numbers,” said Sugarek.

The TCEQ and Sugarek also noted that drinking river or lake water can get bacteria into your system. It can also be ingested through the nose.

The TCEQ advises that swimmers hold their nose shut or use nose clips when taking part in water-related activities in bodies of warm freshwater. This is particularly important to reduce the risk of infection by the naturally-occurring amoeba, Naegleria fowleri.

Sugarek added it’s not a good idea to kick up the bottom of the river bed or lake, especially in warmer water. He also advises not to swim immediately after it rains.

“Anything that runs off directly from the land into the river can have some pathogens or bacteria, but infiltrating through the soils, it does clean up everything out of there. You don’t want to swim in waters that if it just rained, the water is turbid and moving quickly, that’s probably not the safest water to get in. I would wait ‘til it cleared up and return to a spring-like state.”

Click here for more information on the Nueces River Authority.

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About the Authors:

RJ Marquez is co-host of KSAT News Now and reports for Good Morning San Antonio. He's been at KSAT since 2010 and covered a variety of stories and events across the San Antonio area. He also covers the Spurs for on-air and digital platforms, including his Spurs newsletter. RJ has reported stories for KSAT Explains.