The South San Gabriel River was so clear as it flowed past Frank and LaWann Tull’s house on Waterford Lane in Georgetown that they held baptisms for their church in April 2016 and April 2017. But this year they couldn’t.
Around the beginning of April, t he river became blanketed with thick coats of algae that lasted for several weeks, they said.
“We’ve been here 11 years and we’ve never seen anything like this,” said LaWann Tull. “It’s a thick, heavy sludge that in some cases goes from bank to bank.”
The river was running clear last week, with residents saying the algae was swept downstream by recent rain.
The Tulls and at least two other residents said they believe the algae was linked to discharges from the Liberty Hill South Fork Wastewater Treatment Plant a few miles upstream, while a Liberty Hill official said a lack of rain, yard fertilizer or new developments could have been the culprit. Now the Texas Commission on Environmental Quality is investigating.
Commission spokesman Brian McGovern said he couldn’t comment about the investigation but said decaying algae can have negative effects on aquatic life because it lowers the level of oxygen in the water. The investigation is ongoing and could take up to 60 days, he said.
All wastewater treatment plants in the state are required to have a Texas Pollutant Discharge Elimination System permit, which limits the amount of phosphorus and nitrogen they can release to minimize the growth of excessive algae.
McGovern said the city-owned Liberty Hill treatment plant’s permit requires it to take samples of its wastewater discharge once a week to test for levels of ammonia nitrogen, which is commonly found in urine.The daily average levels reported by the city on Jan. 31 and Feb. 28 exceeded the concentration limit allowed, he said.
Wayne Bonnet, the public works director for Liberty Hill, said the wastewater treatment plant began operating in January and discharges daily into the South San Gabriel River. It replaced an older plant with the same name the city operated near the same site that also was discharging into the river until mid-March to early April, Bonnet said.
The environmental commission has issued a proposed order to fine the city of Liberty Hill an administrative penalty of $18,714 for violations at the old plant in 2016 and 2017, though the order has not been finalized. The entire amount of the penalty would be deferred if the city complies with the terms in the order, including conducting employee training and showing at least three consecutive months of compliance with limits on permitted discharges.
The commission also cited Liberty Hill in 2012 after tests from the wastewater treatment plant showed unacceptable levels of ammonia nitrogen, phosphorus and E. coli.
Bonnet said the new plant is discharging 550,000 gallons of treated effluent per day but has a permit that allows it to discharge up to 1.2 millions gallons into the river, Bonnet said. Ultimately it will be allowed to discharge up to 4 million gallons per day into the river, he said.
“The city of Liberty Hill is, to me, on the forefront of using the best technology we can obtain to make sure we are doing the best we can for the environment,” Bonnet said. “We are trying to clean the water to have the least impact on the river.”
The new treatment plant was designed to reduce the levels of nitrogen and phosphorus in the wastewater more than the old plant could, said Aaron Laughlin, the design engineer and project manager for the new plant.
Bonnet said multiple factors could affect the river, “such as, it’s spring and at this point we’ve had low amounts of rain, plus a lot of people have fertilizer in their yards and developments in progress, any of which might potentially affect water quality.”
But other people familiar with the river, including Glen Garey, said they don’t believe the algae was caused by fertilizer or development. Garey is the son of Jack Garey, who donated 525 acres to the city of Georgetown for a park that will have a grand opening June 9. The land is right across the river from the Tulls and includes trails so visitors can go down and wade in the river when the park opens.
Glen Garey said he has spent decades visiting the riverfront part of the land his father donated and couldn’t believe the amount of algae he saw in the river this month.
“I’ve never in 50 years seen the river look like this, and it happened relatively rapidly,” he said this month.
“It isn’t just runoff from yards,” he said.
He also said no new subdivisions have sprung up along the river during the winter.
City of Georgetown spokesman Keith Hutchinson said it was “up to TCEQ to assess the current situation with the South San Gabriel River and take any required action.”
“Wastewater treatment plant discharge creates the possibility for the type of algae growth that is occurring along the South San Gabriel River,” he said.
The Tulls stood by the river in early May looking at the sheets of algae covering it and trying unsuccessfully to move it with rakes and sticks.
“This is a black eye on Williamson County,” LaWann Tull said.