When Mansfield Dam was built from 1938-1942, it was state-of-the-art. One of six dams operated by the Lower Colorado River Authority (LCRA) on the Highland Lakes in Central Texas, each dam generates hydroelectric power and controls floods. However, only Mansfield Dam at Lake Travis was designed to actually hold back floodwaters.
The tallest and most impressive of all the LCRA dams on the Highland Lakes, Mansfield Dam also has the largest power plant, which can generate 108MW of hydroelectric power.
Mansfield Dam hydroelectric turbines produce Direct Current (DC) electricity, which must be converted to Alternating Current (AC) to travel long distances on transmission lines to the LCRA electric service area. The DC-to-AC conversion was first made in the transformer house, immediately behind the Mansfield Dam power house. From the transformer house, power lines tied into high-voltage transmission lines to carry electricity overhead to customers in Austin.
Over time, electric transmission technology improved and modernized. In the 1960s LCRA took the 1940s-era transformers in the transformer house out of service, replacing them with a modern outdoor substation nearby. Today, the infrastructure upgrades at the outdoor substation have continued, as older transmission lines are replaced with new 138kV lines, carrying electricity to an increasingly power-hungry area.
LCRA converted the old transformer house at Mansfield Dam to store equipment needed to maintain the power plant decades ago.
The power plant is off-limits to the public, and tours are not offered.
From the LCRA website: (
visit link)
"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.
Mansfield Dam and Lake Travis
Lake can store up to 256 billion gallons of floodwaters
Built specifically to contain floodwaters
Mansfield Dam and Lake Travis are the only structures in the Highland Lakes chain specifically designed to contain floodwaters. The lake can store as much as 256 billion gallons of floodwaters, helping to manage flooding downstream.
. . .
LCRA and the U.S. Bureau of Reclamation built the dam from 1937 to 1942. . . . The dam was built across a deep canyon at Marshall Ford, a long-time river crossing and settlement. The Corps of Engineers still refers to the structure as Marshall Ford Dam. It was renamed in 1941 for U.S. Rep. J.J. Mansfield, who assisted in the project's development.
FYI: Mansfield Dam
Location: Travis County, 318 river miles from the Gulf of Mexico
When built: 1937 to 1942
Dam dimensions: 278 feet high, 7,089.39 feet long
Primary purposes: Flood management, water storage, hydroelectric power
Generating capacity: 108 megawatts
Water supply storage capacity: 369.8 billion gallons
Spillway elevation: 714 feet above msl
Top of dam: 750 feet above msl Floodgates: 24
Total discharge capacity: More than 133,400 cubic feet per second (cfs):
24 floodgates @ more than 5,250 cfs each
2 turbines @ 2,500 cfs each
1 turbine @ 2,400 cfs
Original name: Marshall Ford Dam"
Here's the cool flickr account for the LCRA, with historic photos: (
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