Buchanan Dam floodgates open for first time since 2019

The Lower Colorado River Authority opened floodgates on Buchanan Dam for the first time since 2019 as Lake Buchanan approaches maximum capacity due to flooding in the Texas Hill Country that’s been ongoing since July 4.

The LCRA opened two gates on the massive dam at around 2 p.m. Monday and might open two more later in the day if needed. Lake Buchanan was around 98 percent full on Monday following the Fourth of July flood and days of heavy rain across Central Texas. Since July 3, the reservoir has risen about 17 feet, from 1,002 feet above mean sea level to 1,019 feet MSL as of Monday. The lake is full at 1,020 feet MSL.

The water from Lake Buchanan runs into Inks Lake, which goes into Lake LBJ and then Lake Marble Falls and Lake Travis. From there, it heads downstream into Austin and beyond.

With floodgate operations underway, the LCRA is advising people to stay off of lakes Buchanan, Inks, LBJ, Marble Falls, and Travis due to fast currents, flood debris, and higher levels of bacteria. The city of Marble Falls took it a step further and closed off all unnecessary access to Lake Marble Falls.

Buchanan’s rapid rise can be attributed to massive amounts of rain across the northern Lower Colorado River Basin, which saw a large volume of rainfall during the Fourth of July weekend. Following that deluge, several inches of rain continued to fall, and more is in the forecast. 

The Colorado River is still pouring into Lake Buchanan at about 38,000 cubic-feet per second as of Monday. For perspective, at the peak of the Fourth of July flood, it flowed at about 74,000 CFS. Its typical flow is around 55 CFS in the summer.

The LCRA has opened floodgates on Inks, Wirtz, and Max Starcke dams to help control floodwaters from Buchanan and the Llano River, which is also dumping enormous amounts of water into Lake LBJ.

The Llano River also saw a rapid rise, shooting up about 13 feet on Sunday and reaching a flow of about 45,000 CFS. The river was much higher during the July 4 flooding, rising about 20 feet and flowing at 126,000 CFS. It normally flows at around 40 CFS in the summer.

The Colorado and the Llano rivers have both been flowing at high rates for a prolonged period of time, remaining at or around flood-stage levels since July 4.

As of Monday, the combined storage of lakes Buchanan and Travis, the two reservoirs in the Highland Lakes chain, is 87 percent, a massive increase from 52 percent just 11 days ago on July 3.

dakota@thepicayune.com