July rains give Lake Buchanan a hearty boost
Before seasonal hot, dry weather settled over Central Texas in mid-to-late July, storms with heavy rain moved across the Lake Buchanan watershed and caused the lake to rise nearly 10 feet.
Thanks largely to the significant rise on Lake Buchanan in early July, the amount of water in lakes Travis and Buchanan combined rose from 71 percent of capacity on July 1 to about 78 percent of capacity, or 1.56 million acre-feet, on Aug. 1.
Lake Travis, the other water supply reservoir in the Highland Lakes, fell about a foot in July as evaporation and water consumption from a diverse group of users – including domestic users, power plants and city residents – has increased with the summer heat.
The Highland Lakes capture water when it rains to ensure the region has a reliable water supply during times of drought. 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.
The amount of water flowing into the Highland Lakes, estimated from measurements at four gauges upstream of the lakes, totaled 203,133 acre-feet in July – about 235 percent of the average for that month. Lake Buchanan captured most of the July inflows – about 92 percent – while about 8 percent flowed into Lake Travis. July 2015 inflows were the eighth highest for the month since 1942.
From the beginning of the year through Aug. 1, Lake Travis rose about 47 feet and Lake Buchanan climbed nearly 21 feet. Inflows from January through July totaled 777,870 acre-feet, or about 98 percent of the average for that time period.
"It's encouraging to see how much the lakes have risen this year, but we still want to see a normal inflow pattern establish itself," said John Hofmann, LCRA executive vice president of Water. "We had good inflows in May, a drier June and good inflows in July. Now, we're looking to the fall to see what El Niño might mean to us."
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 allow 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.