| Environment


Floodgate replacement at Wirtz Dam


The Lower Colorado River Authority is beginning a $76 million, three-year project to remove and replace the 10 floodgates at Wirtz Dam to help ensure the dam continues to operate safely and reliably for years to come


WIRTZ DAM, WHICH CREATES Lake LBJ, was completed in 1951. The dam has nine original floodgates and a 10th floodgate that was added when the original Thomas C. Ferguson Power Plant was constructed in 1974. During a three-year, $76 million project, the Lower Colorado River Authority (LCRA) will remove each of the dam’s 10 floodgates and replace them with new, custom-made floodgates that meet today’s engineering standards. LCRA determined that replacing the floodgates, rather


than refurbishing the existing floodgates, was the best option with the lowest safety risk, lowest environmental risk and least impact to the public. Replacing the floodgates will take about three years, roughly half of what it would take to refurbish the existing floodgates. The work will be conducted on one floodgate at


a time to help ensure the dam remains operational and available to pass floodwaters downstream. The new 120,000-pound floodgates will be assembled in an area south of the dam, then moved to the dam via construction barges and cranes. After each new floodgate is installed and tested for leaks and


commissioned for operation, the construction barge will be moved to the next floodgate to repeat the process until all 10 floodgates have been replaced. “We could do this project more quickly if we


Buchanan Dam floodgates replaced


In a similar project to the Wirtz Dam upgrade, the Lower Colorado River Authority completed a more than 12-year project to upgrade the floodgates at Buchanan Dam back in October 2021 to maintain continued reliable and safe operations at the dam. 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 keep the dam capable of responding to flooding at all times.


In addition to strengthening each floodgate,


crews added 30 stationary remote-operated hoists to enable LCRA to open the floodgates more quickly. The project also added two new traveling remote-operated hoists for the remaining seven floodgates. In the past, crews had to manually move the hoists from floodgate to floodgate. The steel bridge structures over the 37 floodgates that support the hoists were also re-coated to provide long- term protection to the steel.


replaced multiple floodgates at once, but we are in Flash Flood Alley and that is not a viable option,” said John Hofmann, executive vice president of Water. “Dams along the Highland Lakes play a critical role in managing floodwaters, and we have to maintain their readiness at all times.” Work on each floodgate is expected to take about two months. Workers will be on-site beginning in late January 2023. Installation on the first floodgate is scheduled begin in April 2023, and the project is expected to be completed in 2025.


Safety first The project continues LCRA’s long-standing


commitment to public safety. Since fiscal year 2010, LCRA has invested more than $134 million in capital projects at the dams along the Highland Lakes, Lake Bastrop and Lake Fayette, including on the dams themselves and related hydroelectric generation infrastructure. LCRA plans to invest more than $107 million in these types of projects over the next five years. In addition to replacing the floodgates, LCRA will upgrade the hoists that lift the floodgates. Two hoists will be replaced and eight will be refurbished. LCRA will also replace the existing hoist bridge. The dam will remain operational and able to move


water downstream for water supply or flood management purposes throughout the project. The construction contractor will be in continual communication with LCRA staff and will be made aware of any weather conditions that could require floodgate operations. In the event of a major weather event, the construction barge will be moved away from the dam to a safe location. ●


www.waterpowermagazine.com | February 2023 | 27


Above: Wirtz Dam on the Colorado River in Burnet County, Texas Photo: Larry D. Moore CC BY-SA 4.0.


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