Based on rainfall that has already fallen, floodgate operations are not planned at Mansfield Dam, which creates Lake Travis. Lake Travis is now in its flood pool with a current elevation of nearly 682 feet msl. LCRA projects the lake will rise to more than 684 feet msl today and continue to rise to between 686 to 688 feet msl by Sunday. To pass the floodwaters, LCRA is operating hydrogeneration units at Mansfield Dam to release about 5,000 cubic feet per second.

A floodgate downstream at Tom Miller Dam in Austin is partially opened to safely release floodwaters downstream.

Floodgates anticipated at Wirtz, Starcke dams
Upstream of Lake Travis, runoff from heavy rains is streaming into tributaries of the Colorado River and smaller “pass-through” lakes. The Llano River at Llano and Sandy Creek near Kingsland have exceeded flood stage, according to the National Weather Service. These tributaries feed into Lake LBJ, which is formed by Wirtz Dam. As a result, LCRA anticipates beginning floodgates operations later today at Wirtz Dam and at the next dam downstream, Starcke Dam, which forms Lake Marble Falls. Those floodwaters will be captured in Lake Travis, the only flood control reservoir on the Highland Lakes system.

At this time, flood operations are not planned further upstream, at the northern-most dam along the Highland Lakes chain -- Buchanan Dam, based on rainfall that has already occurred. However, these operational plans may change quickly with additional rainfall or changes in conditions.

Operating rules restrict opening floodgates
Lake Travis was specifically built to contain floodwaters until they can be safely released downstream. The lake is operated based on rules from the U.S. Army Corps of Engineers that consider both forecasted lake levels and river levels at locations downstream of Austin. The operating rules limit LCRA from stepping up water releases — for example, by opening one or more of the dam's 24 floodgates — until the lake is forecast to hit 691 feet msl.

Monitoring possible impact from Hurricane Dean
In addition, LCRA is monitoring Hurricane Dean, which is moving into the Caribbean Sea today and is tracking to hit the Texas coast and could bring more rain to the region late next week. Depending on currents and weather conditions, water released from Lake Travis takes roughly a week to reach the coast; thus, by containing floodwaters Lake Travis is holding water that could otherwise ad to flooding problems downstream if the hurricane affects the Colorado River basin.

Boating, swimming safety While Lake Travis remains open to recreational boating, LCRA advises boaters to exercise extreme caution. LCRA personnel have reported seeing heavy debris washing along the Pedernales River, debris that may eventually flow into Lake Travis and make boating hazardous at or near the confluence with the Pedernales River.

LCRA reminds people of the hazards associated with boating or swimming in water that has received runoff from heavy rains. Swimming in natural water bodies after flood events increases your risk of illness caused by bacteria. Higher bacteria levels typically return to normal in about a week to 10 days after the peak runoff.