The Lower Colorado River Authority has completed a more than 12-year project to upgrade the floodgates at Buchanan Dam to maintain continued reliable and safe operations at the dam.
Buchanan Dam, the uppermost dam in the Highland Lakes, is 145.5 feet high and almost 2 miles long. It is one of the longest multiple arch dams in the world. It impounds water for a powerhouse with a capacity of 54.9 MW.
The $51.1 million project took more than a decade because the rehabilitation work was extensive and was performed on only a few of the dam’s 37 floodgates at a time to ensure the ability to respond to flooding at all times.
The project at Buchanan Dam strengthened all 37 floodgates and provided a 1-foot vertical extension on each floodgate to reduce the potential for overtopping and allow more time to open the floodgates during a flood; removed and inspected all gate trunnions, replacing them as needed; upgraded the dam’s electrical system; provided stop logs to hold back water to allow work on the floodgates to take place in a dry environment; upgraded security and safety features; and recoated all the hoist bridges.
“This is a remarkable dam and a remarkable project,” said Timothy Timmerman, chair of the LCRA Board of Directors. “The dam was completed in 1938 using technology and engineering standards of the day. Without changing the dam’s structure, we were able to upgrade the floodgates to meet today’s engineering standards, as well as make them able to respond to flooding more quickly.”
In addition, crews added 30 stationary remote-operated hoists to enable LCRA to open the floodgates more quickly. The project also added two traveling remote-operated hoists for the remaining seven floodgates. In the past, crews had to manually move the hoists between floodgates. The steel bridge structures over the 37 floodgates that support the hoists also were re-coated to provide long-term protection to the steel.
“LCRA operates dams in the heart of Flash Flood Alley, and we take that responsibility very seriously,” said Phil Wilson, LCRA general manager. “We have to stay vigilant and ready to protect the water supply and respond to flooding at any time, and a significant part of that effort involves keeping our dams in excellent condition. We are fully committed to keeping our dams safe and reliable to continue serving the people of Texas.”
With the Buchanan Dam project now completed, LCRA plans to begin conversations with the Federal Emergency Management Agency about potentially allowing Lake Buchanan to rise to a level of 1,020 feet above mean sea level (feet msl) year-round. Under the current agreement with FEMA, the lake must be maintained at or below 1,018 feet msl from May through October and 1,020 feet msl the rest of the year because of concerns it would have been difficult to open the floodgates quickly if the need arose.
LCRA expects any changes to the dam’s maximum operating level to take time, and the lake would not be kept at 1,020 feet msl year-round. Instead, a change in the maximum operating level would mean the lake could rise to that level when circumstances allowed. As a water supply reservoir, water from Lake Buchanan would continue to be used to meet water supply needs.
The recent work at Buchanan Dam is part of LCRA’s commitment to keep its dam infrastructure operating safely and reliably. From fiscal years 2010 to 2020, LCRA invested more than $111 million in capital projects along the Highland Lakes, Lake Bastrop and Lake Fayette. LCRA plans to invest an additional $83 million in these types of projects through fiscal year 2026.
In October 2020, LCRA completed a $10.8 million project to replace each of the floodgates at Tom Miller Dam in Austin, which impounds water for a 17-MW powerhouse, and has begun a similar renovation project at Wirtz Dam. Gate rehabilitation projects also are underway at Mansfield and Starcke dams.
LCRA serves customers and communities throughout Texas. The company produces electricity from coal, natural gas and hydro facilities. It operates six dams with hydroelectric facilities, with a total capacity at these six plants of more than 295 MW.