The Bandera County River Authority & Groundwater District has issued a warning declaring that recreational contact with the Medina and Sabinal rivers “may be hazardous to your health” because of the possibility of contamination related to how hot and still the waterways have become.
The warning issued to media outlets as of Thursday, Aug. 15, says the river authority “strongly advises, at this time, to avoid recreational contact, including swimming, in the Medina and Sabinal rivers and their tributaries.”
“Low to no flows due to drought conditions, combined with sustained high temperatures, have created a potentially hazardous situation for humans and animals,” the warning continues. “These conditions allow for potentially harmful organism to be present in the water.”
David Mauk, the BCRAGD general manager, said the warning was not based on high readings of specific bacteria like E. coli that is regularly tested for in the rivers. Instead he said it was a “generalized warning” associated with the likelihood that health hazards could exist in water exposed to the heat and drought conditions that have been present for weeks in Bandera County.
“With low (water) flow and 100-degree temperatures, there will be stuff in there, not just E. coli,” said Mauk. “You’re basically creating a stew there.”
It’s the areas of the rivers that are beginning to pool up and become stagnant that are the riskiest, not the area where water is still flowing fairly well, the general manager said.
“If you’re in parts of the river that are getting stagnant, we don’t recommend getting in there,” said Mauk. “I wouldn’t.”
Colby Miller, who owns the Medina River Co. which provides inner tubes and transportation so visitors can float down sections of the Medina River, said he assigns employees to check water flow and the presence of algae or other unusual growth in the areas of the river that the company sends customers to so hazardous areas can be avoided.
Water flow in the area the river company uses has not fallen to hazardous levels, Miller said. But if testing done by the river authority shows the situation is worsening, he said his float tours would be shut down temporarily.
Mauk said the river authority received a lot of calls from the public about water quality after blue-green algae in waters in other parts of the country, including in an Austin lake, were believed to have produced toxins that killed dogs exposed to the water.
No evidence of that algae has been detected in Bandera County, but that’s not a guarantee it does not exist, the general manager said.
Last August, extreme heat and inadequate water flow convinced the river authority to erect signs along the Medina River with the same kind of warning that has been issued this year.
Mauk said more rainfall in the area should correct the problem.