Big gains for lakes after heavy rain
The Kingsland Slab was flooded as of May 6, 2024, due to a raging Llano River. The water is destined for Lake LBJ and eventually Lake Travis. Staff photo by Dakota Morrissiey
Heavy, consistent rainfall across the Colorado River Basin over the past 10 days, from April 26 through May 6, resulted in the first major gains for lakes Buchanan and Travis in three years. The two reservoirs could continue to rise due to the steady and powerful flows of the Colorado and Llano rivers.
Lake Buchanan has risen by nearly 3 feet and Lake Travis by almost a foot since the end of April. The last time the lakes rose this quickly in a month was in May 2021 for Buchanan and June 2021 for Travis.
As of noon Monday, May 6, Lake Buchanan sits at 998 feet above mean sea level, up from 995.14 msl on April 30, the highest since August 2023. Buchanan has gained over 40,800 acre-feet of water since the storms began around April 26, bringing its current total volume to 459,387 acre-feet, or 52 percent full.
As of noon Monday, Lake Travis sits at 631.54 msl, up from 630.62 msl on April 30, the highest since December 2023. Travis has gained over 11,815 acre-feet of water since April 26, bringing its total volume to 435,798 acre-feet, or 39 percent full.
The rise in lake levels can be attributed even more to rainfall in counties farther north and west in the Colorado River Basin that contain countless tributaries that feed into the Colorado and Llano rivers.
According to Lower Colorado River Authority Hydromet rain gauges, as measured since April 26, Marble Falls has received 2.44 inches of rain, Burnet 3.5 inches, Kingsland 2.91 inches, Buchanan Dam 3.01 inches, and Llano 1.94 inches.
The LCRA Hydromet showed the real rain gains for the Colorado River, which feeds Lake Buchanan, were made in Mills, Brown, McCulloch, San Saba, and Lampasas counties. Some gauges in these counties measured over 9 inches of rainfall and many measured over 5 inches since April 26.
The Hydromet also showed several inches of rain on many of the gauges across the Llano River’s watershed in remote portions of Llano County and in Mason and Kimble counties since April 26.
The Colorado and Llano rivers began surging on May 3 with the consistent rainfall, and their flows have remained steady into Monday.
The Colorado River was flowing at 1,200 cubic-feet per second when the surge began on May 3, up from about 200 cfs on May 2. The river then rocketed to a peak flow of over 22,600 cfs on Sunday, May 5. It was at 20,400 cfs as of noon Monday.
The Llano River was flowing at 1,400 cfs when the surge began on May 3, up from about 75 cfs on May 2. The river leapt to a peak flow of about 6,300 cfs on Sunday but had dropped back to 1,400 cfs as of noon Monday.