Lake Austin drawdown discussions continue after 2,000 grass carp enter water

AUSTIN (KXAN) -- The push to lower water levels at Lake Austin continues as shareholders plan to meet with city of Austin officials next week. Business owners and residents said that lowering water levels will help stop the spread of a invasive plant that is dangerous to swimmers and boat owners.

On Friday, Eric Moreland with Friends of Lake Austin posted a video on social media announcing a public meeting held by the city. The meeting is scheduled over Zoom on Nov. 18 at 6:30 p.m.

"At the meeting, we’ll update you about hydrilla and stocking of sterile grass carp as well as a potential lowering of the lake in 2026," a statement read on the meeting invite.

Over the summer, hydrilla blooms spread across the lake. In June, a survey found that only 5% of the lake had hydrilla in it. By late summer, a new survey found hydrilla had spread to 38%.

"We have not been able to take out our boat pretty much all summer. It gets caught in the in the prop and it gets, you know, sucked into the engine," said Cynthia Seifert, who lives near Mansfield Dam.

A similar level of hydrilla in the early-2000's led to a movement to remove the hydrilla, which the Friends of Lake Austin said can entangle boaters and swimmers.

"We've gotten to the point where we actually don't even go in the water out in front of our home because it's so thick," Seifert said.

This fall, the group began a push to drawdown the lake by several feet. They cited studies that said a drawdown can help kill off hydrilla. The city argued the opposite, showing studies that found a drawdown has no impact.

"It hasn't been drawn down, I think, now for almost ten years," said Jacque Barton, who lives near Seifert.

The city said that the Lower Colorado River Authority (LCRA) has final approval on a lake drawdown, but this might not be possible. The LCRA told KXAN that following the winter storms, all hydroelectric operations in Texas are required to work at peak capacity during the winter months. This means a drawdown would not be possible until after winter.

Lake Austin passes through Tom Miller Dam, a smaller hydroelectric operation on the Colorado River. Water would move much slower through during a drawdown.

"It kind of seems like the tails wagging the dog a little bit.," Moreland said about the decision.

The city must make a formal request for a drawdown. Homeowners and businessowners, like Moreland, point out that a drawdown would not only allow the group to remove the hydrilla, but also do much needed repairs on docks.

"If requested by the City of Austin, LCRA is open to discussing options that best serve our customers and Central Texas," said a spokesperson with LCRA in a statement.

The city released 1,955 sterile grass carp into Lake Austin on Wednesday, Nov. 5. This is in addition to the 350 sterile grass carp released this past summer, bringing the total to 2,300. Grass carp feed on hydrilla as their primary food source.

“What studies have shown is that as long as there is hydrilla present, they will kind of focus on that resource, allowing other plants to persist and thrive,” said Dr. Brent Bellinger, conservation program supervisor with the city’s Watershed Protection Department.

Moreland hopes that during talks next week, the city can explore more grass carp releases and plan surveys to determine hydrilla growth.

He worries that by next spring, the hydrilla may spread too far. "We're essentially out of time."