Dry August results in low inflows to Highland Lakes
Little water flowed into the Highland Lakes during a hot and unusually dry August in the Texas Hill Country.
Inflows, or the amount of water flowing into the Highland Lakes estimated from measurements at four gauges upstream of the lakes, in August totaled 6,113 acre-feet – about 10 percent of the monthly average. August 2015 inflows were the 10th lowest for the month since 1942, when Mansfield Dam was completed. (An acre-foot of water is 325,851 gallons.)
Lake levels dropped slightly in August without substantial inflows and as evaporation and water consumption from a diverse group of users – including power plants, city residents and domestic users – increased with the summer heat. The amount of water in lakes Travis and Buchanan combined decreased from about 78 percent of capacity, or 1.56 million acre-feet, on Aug. 1 to 75 percent of capacity, or about 1.51 million acre-feet, on Sept. 1.
The Highland Lakes capture water when it rains to ensure the region has a reliable water supply during dry times. Lakes Travis and Buchanan provide drinking water to more than a million people and water to industries, businesses, the environment and agriculture in the lower Colorado River basin.
As of Sept. 1, Lake Travis was about 45 feet higher than on Jan. 1, while Lake Buchanan was 20 feet higher. Inflows from January through August totaled 771,708 acre-feet, or about 90 percent of the average for that time period.
"Lakes Buchanan and Travis received a tremendous boost earlier this summer, but inflows into the lakes in August were the lowest we've seen all year," said John Hofmann, LCRA executive vice president of Water. "We're cautiously hopeful that more normal inflows will return this fall with El Niño's influence on our weather pattern."
In order to preserve the water supply during the drought, LCRA requested emergency drought relief from the state to cut off Highland Lakes water to most interruptible water customers in 2012, 2013, 2014 and 2015.
LCRA also is increasing the water supply for the region by building the first significant new water supply reservoir in the lower Colorado River basin in decades. The Lane City Reservoir is the first project that will enable LCRA to capture and store significant amounts of water downstream of the Highland Lakes near the Texas Gulf Coast. The reservoir could add up to 90,000 acre-feet per year to LCRA's water inventory and is expected to be completed in 2018. The new reservoir will help reduce the amount of water that otherwise would be required to be released from the Highland Lakes.