A malfunction at Longhorn Dam that caused Lady Bird Lake to lose water has been fixed

If you happened to be near Austin’s Lady Bird Lake on Monday, you might have noticed it looked different.

The lake level, which usually stays constant year-round, had dropped by about 2 feet, exposing stretches of muddy, sometimes smelly, shoreline.

The cause was a problem at Longhorn Dam on Sunday night.

“We experienced a control system malfunction at Longhorn Dam, which affected the operation of the bascule gate, a movable drawbridge-like gate allowing precise water level control,” Austin Water’s Martin Barbosa said in an email. “It was an isolated incident, and the root problem is now corrected.”

The Longhorn Dam was built in 1960 to create a reservoir to serve the Holly Power Plant. The power plant is now gone, but the reservoir, now commonly known as Lady Bird Lake, remains as an iconic city amenity.

The dam’s age and maintenance has sometimes been a challenge for the city.

In 2013, a massive flood led to a problem with the dam gates that threatened to drain Lady Bird Lake of water.

After that, the city invested in upgrading the dam. Austin Energy, which had been responsible for dam management since the days of the Holly Power Plant, also transferred operations to Austin Water.

Austin Water did not provide many details on what caused the most recent problem.

The area around the dam has been buzzing with heavy equipment as contractors work to install a new “wishbone bridge” and pedestrian tunnel nearby.

KUT has followed up with questions about whether that activity may have contributed to the dam malfunction and about how much water was lost downstream.

The surface area of Lady Bird Lake covers approximately 468 acres.

Austin Water works in conjunction with the Lower Colorado River Authority to maintain the lake level at around 428 feet above sea level, by moving water through the Tom Miller Dam upstream and the Longhorn Dam downstream.

By Tuesday morning lake levels had returned to normal according to data from LCRA.

This story was produced as part of the Austin Monitor’s reporting partnership with KUT.

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