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 lakes Travis and Buchanan are not constant-level lakes and are designed to fluctuate.
Inflows and lake level projections
Widespread, soaking rains over the Highland Lakes watershed throughout September helped saturate the soil, raise lake levels and ease drought conditions. The rain was a welcome change from a hot and dry summer.
At 112,411 acre-feet, inflows into the lakes in September were about 114 percent of the historic monthly average. September inflows were more than the total inflows for January through August 2018. Inflows are the amount of water flowing into the lakes estimated from measurements at four gauges upstream. (An acre-foot is 325,851 gallons.)
Despite the rain in September, the first nine months of the year were so dry that inflows for 2018 are still far below average. Inflows for January through September 2018 are the sixth lowest on record for that time period.
Here are LCRA's six-month projections for Lake Travis and Lake Buchanan based on conditions ranging from very wet to very dry.