The Highland Lakes were created to manage floods and capture water when it rains to ensure the region has a reliable water supply during dry times. Lakes Buchanan and Travis – the region's water supply reservoirs – provide water for more than a million users, including communities, industries, businesses, agriculture and the environment in the lower Colorado River basin. Together, lakes Buchanan and Travis can hold about 2 million acre-feet of water. It's important to note that none of the Highland Lakes are constant-level lakes.
Inflows and lake level projections
Lakes Travis and Buchanan began 2019 as essentially full after widespread rains in late 2018. LCRA's six-month projections for Lake Travis and Lake Buchanan show lake levels are expected to remain above normal, even if conditions turn very dry.
Though the first eight months of 2018 were extremely dry, inflows toward the end of the year were well above average. At 120,321 acre-feet, inflows into the lakes in December were about 177 percent of the historic monthly average and were the second-highest monthly inflows for 2018. The highest monthly inflows – 1.3 million acre-feet – occurred during historic flooding in October. The October inflows were the highest October inflows in history and the fourth highest of any month on record.
Annual inflows for 2018 rank as the 15th-highest yearly inflows on record. Inflows are the amount of water flowing into the lakes estimated from measurements at four gauges upstream. (An acre-foot is 325,851 gallons.)