Posted: Mon, 14 May 2012 07:41 AM - 16,839 Readers
By: Farzad Mashhood
photography by Jay Janner
A storm that dumped about 1 1/2 inches of rain last week on Lake Travis was not a drop in the bucket, like many of the downpours that have left the main reservoir for much of Central Texas in the same more-than-half-empty shape it has been in since August.
"It was several drops in the bucket," said Clara Tuma, a spokeswoman for the Lower Colorado River Authority, which operates Lake Travis.
The 35,000 acre-feet of water that lakes Travis and Buchanan gained since Thursday night leaves them about 1 million acre-feet shy of being full and about 700,000 acre-feet short of their May average. An acre-foot of water is about 326,000 gallons, or enough water for three typical Central Texas households in a year.
Thursday's storm, which brought 1 1/2 to 3 inches of rain in most parts of Central Texas, moved fast and brought nickel-size hail to Round Rock and 50 mph winds to Hutto, while temporarily taking power from 3,000 Austin homes and businesses. Water in creeks, and even some flooded roads, was moving swiftly, and rivers pushed to anemia by the past year's drought got a quick boost. The powerful thunderstorm had the makings of a downpour that would lead to speculation on whether the drought is over.
Sunday afternoon, LCRA officials maintained that the drought persists and lakes Travis and Buchanan, the LCRA's pair of water supply reservoirs, were just shy of the 1.005 million acre-feet level to be optimistically called half-full.
Thursday night's rain led to a sharp overnight increase in Lake Travis, which jumped by more than a foot from just before the storm hit to Friday's 1:30 p.m. height of 639.63 feet. By Sunday night, Lake Travis' level had risen by almost 3 feet to 641.33. Buchanan went up by only about a foot to 997.31.
Both lakes are still well below their May averages — Travis by 30 feet and Buchanan by 16 feet.
The nearly 3-foot rise since Thursday is the biggest the lakes have seen since the days following a March 20 storm, when Lake Travis went up 4 feet in a day.
That downpour, which brought about 2 inches of rain to the region, eventually led to a 6-foot rise in Lake Travis and a more-than 64,000 acre-foot increase in lake storage over the next four days.
The Brazos River Authority's pair of lakes in Williamson County, lakes Georgetown and Granger, has been steady since the storm. The Edwards Aquifer, which supplies water to San Marcos, has gone up about 3.3 feet since Thursday.
Before last week's storm, the LCRA's lakes remained steady despite rains earlier in the week that totaled 1.37 inches at Camp Mabry from May 6 to Tuesday.
"The soils get dried out, and so the ground soaks up rainfall at the front end of a storm before you can get any runoff," said Dan Yates, supervisor of the LCRA's river operations center. "Texas can soak up a couple inches (of rain), no sweat." The rain from early last week, however, primed the soil, rivers and streams to send more inflows into the lake system, Yates said.
An overnight storm isn't what will end Central Texas' drought, which, according to the latest national drought monitor, is prevailing in about half the region.
"What we really need is a season of rain," Yates said.
