LCRA to begin floodgate operations at Mansfield Dam 

Planned releases Saturday will move floodwaters downstream in a controlled, orderly manner; operations also planned at Tom Miller Dam in Austin

July 17, 2026

Key Takeaways

  • LCRA plans to open at least two floodgates at Mansfield Dam on Saturday, July 18 — the first floodgate operation there since 2019 — and open one floodgate on Friday, July 17, at Tom Miller Dam.
  • These are planned, controlled releases as Lake Travis rises into its flood pool and does what it was designed to do: store floodwaters until they can be moved downstream safely.
  • Flows below both dams will be higher and faster than usual, so people downstream should secure property and stay clear of the water near the dams.
  • Be careful of potential debris and bacteria in the lakes as the flooding continues.
AUSTIN, Texas – The Lower Colorado River Authority will open at least two floodgates at Mansfield Dam on Saturday, July 18, as Lake Travis rises into its flood pool following recent rains across the Hill Country. This will be the first floodgate operation at Mansfield Dam since 2019.

The first floodgate is expected to open at about 6 a.m. Saturday, with a second gate expected to be opened about 1 p.m. LCRA also plans to open one floodgate at Tom Miller Dam on Lake Austin on Friday afternoon. Additional floodgate operations may be needed depending on conditions. Both dams are in Travis County.

These are planned, controlled releases. Lake Travis is doing what it was built to do: capture floodwaters and hold them until they can be moved downstream safely. At present, the river downstream has capacity available to accept these flood releases.

“The Highland Lakes system is operating as designed, moving water through the lakes in an orderly manner,” said John Hofmann, LCRA executive vice president of Water.

How the system works

Rain that falls in the upper basin flows down area tributaries into the Highland Lakes. Over the past several days, storms brought 1-4 inches of rain to much of the region, with some areas near Junction and Fredericksburg receiving as much as a foot of rain. That runoff now is moving downstream toward Lake Travis, the only lake in the chain designed to store floodwaters.

Lake Travis is considered full for water supply purposes at 681 feet above mean sea level. Above that level, water enters the lake’s flood pool, which can hold an additional 776,000 acre-feet. When the lake rises into its flood pool, LCRA conducts flood operations at Mansfield Dam in accordance with the Army Corps of Engineers Water Control Manual.

Releases are based on the lake level, expected inflows and downstream river conditions and are designed to move water downstream without significantly affecting conditions along the river.

LCRA operates Tom Miller Dam consistent with an agreement with the City of Austin.

Moving floodwaters downstream in a measured way keeps the flood pool available for future storms. Summer rain events are part of life in this region, which is known as Flash Flood Alley, and the system is built to manage them. Learn more.

Flood operations this week

LCRA began moving floodwaters through the Highland Lakes on Thursday, opening floodgates at Wirtz Dam on Lake LBJ and Starcke Dam on Lake Marble Falls. Multiple floodgates at each dam remain open, allowing flows to pass downstream into Lake Travis. LCRA hydrologists and engineers in the River Operations Center are monitoring conditions around the clock using the Hydromet, LCRA’s network of more than 280 river and weather gauges across the basin.

With this event, LCRA’s two primary water supply reservoirs, lakes Buchanan and Travis, both will be full for the first time since fall 2019.

What to know if you live near the water

Flows downstream of Wirtz, Starcke, Mansfield and Tom Miller dams will be higher and faster than usual while the floodgates are open. People downstream should secure boats, docks and other property, stay clear of the water near the dams, and keep an eye on conditions. As always, avoid low water crossings, and never drive through flooded roads.

What to know if you want to recreate on the lakes

Anyone wanting to swim or boat on the lakes should be aware of the fast-moving currents, as well as storm debris that has been washed into the lakes. Bacteria levels typically rise significantly after heavy rains and flooding, and swimmers should avoid murky, stagnant, smelly or oily water, as bacteria tends to congregate in those areas.

Stay informed

Contact Info

Clara Tuma
512-578-3292
After hours: 512-944-6719
[email protected]

About LCRA

The Lower Colorado River Authority serves communities across Texas by managing the lower Colorado River, generating and transmitting wholesale electric power, providing clean water supplies, operating telecommunications infrastructure, and owning parks for outdoor recreation. LCRA delivers power, water and infrastructure that support the region’s growth and quality of life. LCRA and its employees are committed to fulfilling our mission to enhance the quality of life of the Texans we serve through water stewardship, energy and community service. Created by the Texas Legislature in 1934, LCRA receives no state appropriations.