GBRA drops river barrier after big rain
By BY DIANNA WRAY - DWRAY@VICAD.COM
July 17, 2012 at 2:17 a.m.
Updated July 18, 2012 at 2:18 a.m.
Go to gbra.org for more information on the Guadalupe-Blanco River Authority
The Guadalupe Blanco River Authority has lowered the saltwater barrier on the Guadalupe River after torrential rains soaked the Crossroads last week.
The barrier was built as a way to control water diversion and to protect the water supply by keeping water levels stable and preventing salt water from San Antonio Bay from moving upstream when river water levels are low.
In the wake of a record drought that gripped Texas in the 1950s, the GBRA put in two 50-foot-long inflatable barriers to span the river in 1965.
The barrier is located 10 miles upstream from the mouth of the Guadalupe, near Tivoli. Hooked to concrete pillars, the barrier fills with water when in use, raising the water level of the river and blocking salt water from traveling upstream. The barrier is emptied of water and lies at the bottom of the river when not in use.
In the face of a drought that has gripped half the nation this year, the river's level dropped to 3 feet mean above sea level. GBRA workers raised the barrier from the river bottom two weeks ago to raise water levels to about 4 feet mean above sea level, insuring a steady supply to GBRA water customers and preventing saltwater from moving up the river from the bay.
Last week, the Crossroads received four to six inches of rain, said Doug Vogelsang, a meteorologist with the National Weather Service.
The downpour raised water levels in the Guadalupe to 6.7 mean feet above sea level, allowing them to lower the barrier, Herb Wittliff, manager of GBRA's Port Lavaca operations, said.
The barrier created a 2- to 4-foot drop downstream and the GBRA issued a boating caution for anyone who uses the lower Guadalupe for water recreation or fishing when the barrier was put in place.
The barrier has been lowered, but Wittliff said it may be raised again if water levels drop.
"I think after this passes on through, we'll get back to a low, but steady situation," Wittliff said, noting that they will be watching river levels to determine if the barrier needs to be put back up. "We'll have to look at it," he said. "It's a day-to-day thing."