Lake Travis in 2011 as the severe drought began to grip the state. File photo
FROM STAFF REPORTS
AUSTIN — Lower Colorado River Authority officials are considering a move that would keep a little more water in Lake Travis, but folks along Lake Austin could see a dip in their lake levels.
LCRA General Manager Becky Motal said staff is studying the idea of lowering Lake Austin two to four feet to make room for rainfall that enters the basin below Lake Travis and the upper Highland Lakes.
“But we’re not talking about permanently changing the operating guidelines. We’re not talking about permanently lowering the lake,” she said. “This is just a temporary strategy to help us avoid mandatory curtailment that we might be looking at in the next several weeks or couple months.”
If the combined storage of lakes Travis and Buchanan falls below 600,000 acre-feet of water, LCRA would begin a pro rata curtailment of firm-water supply after ceasing interruptible supply. Firm supply is defined as water available even during a severe drought for cities, industry and electric power plants, according to LCRA.
Examples of interruptible includes customers such as agriculture producers.
If the combined storage of the two reservoirs hits or drops below 600,000 acre-feet, it would mark this current drought as worse than the Drought of Record, which occurred from the late 1940s through the late 1950s.
Lake Buchanan and Lake Travis currently hold about 671,743 acre-feet of water. An acre-foot of water is about 326,000 gallons.
Under the strategy LCRA staff is considering, Lake Austin would drop two to four feet, but not because the authority would release water downstream. Motal explained the city of Austin draws water from Lake Austin, and LCRA would not release Lake Travis water to completely refill it.
Lake Austin also loses water to evaporation.
“It’s a strategy where then you wouldn’t have to take water out of Lake Travs (to refill Lake Austin),” Motal said.
This would open up some space in Lake Austin that could capture rainfall that falls below the upper Highland Lakes.
Rainfall that falls below lakes Buchanan’s and Travis’ recharge zone often simply runs downstream unused. This plan would give LCRA flexibility in capturing rain that enters the lower Colorado River basin below the two main reservoirs.
Motal said the LCRA board has not approved this concept yet.
“(This is) one of multiple strategies we’re trying to employ, including conservation, so we can get through this drought,” she said.
Lake Austin is considered a “pass-through” lake, so water runs through it instead of getting stored in it. LCRA also classifies Lake Marble Falls, Lake LBJ and Inks Lake as pass-through lakes.
Motal said the staff is not considering the measure for the other pass-through lakes at this time.