Lake Austin Residents Brace For Man-Made Deluge As Dams Open

AUSTIN, TEXAS — Planned water releases at area dams to relieve overflow from recent heavy rains that caused flooding across Central Texas has prompted officials to urge residents to safeguard themselves and their property.

The Lower Colorado River Authority has already opened four floodgates at Mansfield Dam, but current overflow dictates the need to open four more floodgates by mid-Thursday, officials said on Wednesday. This means that come Thursday, a total of eight gates will be open at the dam — a record number for the structure, and the greatest number of floodgates opened simultaneously since six in 1957.

This comes after heavy rains descending on Central Texas since the beginning of the week unleashed historic flooding levels causing widespread property destruction and a handful of deaths. And the region isn't out of the woods yet, as the National Weather Service on Wednesday issued a new flash flood watch for the region in effect until 7 p.m. Thursday, ahead of more rain moving in from the Gulf of Mexico as early as Wednesday night.

Yet even before the arrival of those new, and mercurial, storm systems, residents along Lake Austin in particular and the Highland Lakes Watershed in general can expect a deluge — not of nature's hand, but a man-made onslaught via the needed water releases from overburdened dams. The National Weather Service late Tuesday issued a flash flood warning to area residents ahead of those anticipated man-made torrents caused by opened floodgates.

WATCH LAKE TRAVIS WEBCAM

"The Highland Lakes watershed is experiencing historic flooding," LCRA officials wrote on their website. "This is a serious situation and people should take action to protect people and property. We encourage everyone who may be affected by the current flooding on the Highland Lakes and rising levels downstream of Lake Travis to take immediate action to keep themselves and their property safe. "

The Texas Highland Lakes is a chain of six fresh water lakes in Central Texas formed by six dams on the Lower Colorado River, which winds southeast from West Texas to Matagorda Bay and the Gulf of Mexico. The dams and lakes comprising the Texas Highland Lakes chain are Buchanan Dam at Lake Buchanan; Inks Dam at Inks Lake; Wirtz Dam at Lake LBJ; Max Starcke Dam at Lake Marble Falls; Mansfield Dam at Lake Travis; and Tom Miller Dam at Lake Austin.

Related stories:

Nature's Fury: Central Texas Rain Leaves Destruction In Its Wake

Incoming Heavy Rain Prompts Flood Warnings For Travis, Williamson

Flash Flooding Alerts Issued After Heavy Central Texas Rain

How To Help Central Texas Flood Victims

Texas Transportation Officials To Assess Storm Damage

As of 8 p.m. on Wednesday, Lake Travis was at 698.91 feet — well above 100 percent filled, according to the LCRA. For some context, consider this: In the 24-hour period from noon Tuesday to noon Wednesday, Lake Travis climbed 21 feet. Stated another way, more water has been captured at Lake Travis in the last week than the city of Austin typically uses in four years, officials have noted.

That calculus amounts to the need for releasing water from the man-made reservoir, and quickly. Should water exceed 700 feet — something that's never happened but now precariously close to that level — the runoff will spill over its banks, and not in the controlled manner the LCRA would undertake.

Controlled or not, lakefront residents should take precautions ahead of the water release, officials stressed.

"Releases from Lake Travis will cause higher levels in Lake Austin, Lady Bird Lake and the Colorado River downstream of Austin," LRCA officials said. "Water released from Mansfield Dam will travel down the Colorado River to Matagorda Bay."

Heightening the urgency of those warnings is the faster velocity at which that runoff will travel given its rain-bolstered mass: "Under typical conditions, water released from Mansfield Dam would take about one day to get to Bastrop, two days to Columbus, four days to get to Wharton and five-plus days to reach Matagorda," LCRA officials explained. "Travel times will be faster because we're in a flood."

LCRA opened four additional floodgates at Buchanan Dam on Wednesday morning, officials noted. This brings the total number of floodgates open at Buchanan Dam to eight, the LCRA added. And they're not done yet: "Flood operations continue at Buchanan, Inks, Wirtz, Starcke, Mansfield and Tom Miller dams," LCRA officials said. "Flows throughout the Highland Lakes are swift and high."

In preparation for the water release, LCRA has closed lakes Buchanan, Inks, LBJ, Marble Falls and Travis until further notice. For more information, read the LCRA's Flood Operations Report for more on current conditions on the Highland Lakes. For rainfall totals, stream flow and lake levels, visit LCRA's Hydromet.

Get Patch's Daily Newsletter and Real Time Alerts

>>> Image via Shutterstock