LCRA operates six hydroelectric dams on the Highland Lakes of central Texas. Buchanan Dam backs up water to create Lake Buchanan. Five of the 6 LCRA dams were built for the primary purpose of making hydroelectric power. Although all LCRA dams can manage floodwaters, only Mansfield Dam, downstream at Lake Travis, was built to actually hold back floodwaters.
From the LCRA website: (
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"LCRA dams form the Highland Lakes
Structures designed for flood management, water supply, hydroelectricity
LCRA operates six dams on the lower Colorado River in Central Texas: Buchanan, Inks, Wirtz, Starcke, Mansfield and Tom Miller. These dams form the six Highland Lakes: Buchanan, Inks, LBJ, Marble Falls, Travis and Austin.
Flood management
Each of the dams was built to manage floods, but Mansfield Dam, which forms Lake Travis, is the only one designed to hold back floodwaters.
. . .
Electricity
The dams in the Highland Lakes chain have hydroelectric generation stations that contribute to the Central Texas energy supply. Together, the hydroelectric plants at the dams can provide more than 295 megawatts of electricity per year.
Hydroelectricity was once the major source of power for LCRA's electric service area, but hydroelectric generation now is primarily a byproduct of other river operations. Water is moved through hydroelectric generation solely to create power at the request of the Electric Reliability Council of Texas during a power emergency.
From the Buchanan Dam page: (
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Buchanan Dam and Lake Buchanan
Two-mile-long structure is an architectural rarity
Oldest of the Highland Lakes chain
The dam, completed in 1938, is an architectural rarity. Stretching for more than two miles, Buchanan is considered the longest multiple-arch dam in the nation. Builders no longer use the design because the amount of labor required makes construction too expensive. Today's dams require far less labor, but a thousand times more materials.
Buchanan Dam and Lake Buchanan were the first completed in the Highland Lakes chain. Their primary purposes are to store water and supply hydroelectricity. They are named for U.S. Rep. J.P. Buchanan, who helped secure federal funds to complete the project after the original builder declared bankruptcy.
?FYI: Buchanan Dam
Location: Burnet and Llano counties, 414 river miles from the Gulf of Mexico
When built: Started 1931, completed 1935 to 1938
Dimensions: 145.5 feet high, 10,987.55 feet long
Primary purpose: Water supply, hydroelectric power
Generating capacity: 54.9 megawatts
Water supply storage capacity: 285.3 billion gallons
Top of dam: 1,025 feet above msl
Floodgates: 37
Discharge capacity: 347,300 cubic feet per second (cfs):
7 large floodgates @ 18,800 cfs each
30 small floodgates @ 7,000 cfs each
3 turbines @ 1,900 cfs each
Original name: Hamilton Dam
Details on Lake Buchanan
Lake area: 22,017 acres
Elevation when full: 1,020 feet above mean sea level (msl)
Volume when full: 875,588 acre-feet
Historic high: 1,021.4 feet above msl on Dec. 20, 1991
Historic low: 983.7 feet above msl on Sept. 9, 1952
Target operating range:
May to October: at or below 1,018 feet above msl
November to April: at or below 1,020 feet above msl
100-year flood level at dam: 1,021 feet above msl
Dimensions: 30.65 miles long, 4.92 miles at widest point