The Colorado River’s long history of extreme floods and droughts begged for an engineering answer. In the 1930s construction of Lake Buchannan and Inks Lake launched the ambitious system of six dams designed to control Texas’ Colorado River and creating the Lower Colorado River Authority (LCRA). In addition to water management, the Highland Lakes were instrumental in ‘electrifying’ Central Texas and the Hill Country, as, at the encouragement of then Representative Lyndon Johnson, the LCRA proselytized electricity distribution and consumption via a late ‘30s-40s campaign to convince communities to purchase their local distribution systems and buy power from LCRA. Almost all communities did — and saw retail electric bills drop almost by half from the criminal rates (LBJ felt) private utilities had charged. LCRA also sponsored "electric fairs" with local merchants to introduce residents to the benefits of electric appliances. As a whole, the Highland Chain of Lakes were awarded Historic Civil Engineering Landmark of Texas status in 2000.
With Buchanan and Inks already under construction, in 1936 the LCRA Board chose what is known as the Hughes site at Marshall Ford – twenty miles upstream from Austin – as the site for what was to be the Colorado’s main flood-control dam. Due to its similar size, the design and bidding process for the “Marshall Ford Dam” was greatly accelerated by utilizing documents from the Grand Coulee Dam, under construction on the Columbia River. Although the proposed lake would certainly be massive, land acquisition was no great hurdle, as the steep cedar-filled canyons were primarily remote ranch lands.
The construction contract was awarded to Brown & Root – a risky prospect for the relatively young company, especially since funding was only secured for the first half of the project. At the ground-breaking ceremony on February 19, 1937, Secretary of the Interior Harold Ickes announced that the Marshall Ford Dam would be built in two phases: the first 190 feet in height and the second, 266 feet, which would double the cost from $10 million to $20 million.
The catastrophic flood of ’38 and subsequent investigation of LCRA [Buchanan Dam was suggested to have increased the flood’s intensity] led LBJ to inform a general meeting at the House of Representatives Chamber of the State Capitol that, “the federal government came in and said it was advisable, if we were to control such floods as we had in 1935 – and last week – to raise that Marshall Ford Dam from 109 feet to 265 feet.” This would effectively increase the flood storage capacity of Lake Travis by an additional 800,000 acre-feet. The additional funding for the higher dam was secured by Texan Sam Rayburn (the majority leader of the House) from the U.S. Bureau of Reclamation and the Public Works Administration. The generators at Marshall Ford went into operation on January 27, 1941, and construction was completed in May 1942.
On February 21, 1941, the LCRA Board voted to change the dam’s name to Mansfield Dam, after U.S. Representative J.J. Mansfield, then eighty years old.
Lake Travis has the largest storage capacity of the Highland Lake reservoirs. Its ‘serpentine’ course stretches 65 miles (105 km) upriver from the Austin metro in western Travis County to the Max Starcke Dam in southern Burnet County, just southwest of Marble Falls. In addition, the Pedernales River, a major tributary of the Colorado River, flows into the lake from the southwest in western Travis County.
Mansfield Dam and Lake Travis are the only structures in the Highland Lakes Chain *specifically* designed to contain floodwaters in the lower Colorado River basin. The lake can store as much as 256 billion gallons of floodwater, helping prevent (or at least mitigate) destruction downstream in all but “Biblical” flood conditions. When the elevation of the lake exceeds 681 feet above mean sea level (msl), LCRA begins floodgate releases under the direction of the U.S. Army Corps of Engineers. The amount and duration of the releases varies in response to weather and flood conditions above and below the dam.
This lake also provides water for the Austin Metro and irrigation water for farmers downstream, generates electricity, and is a favorite water recreation destination.
A two-lane highway, RM 620, originally crossed at the top of the dam, but traffic congestion due to Austin’s growth and increasing popularity of the Lake for recreation prompted the state to build a four-lane highway bridge on the downstream side of the dam. Public traffic is no longer allowed on the road across the dam.
The posted coordinates center on Mansfield Dam itself. The best view of the downstream face is actually a drive-by: across the RM 620 bridge just downstream of the Lake. This is not great for photography, however.
There is a viewing area, reachable from both directions of traffic, at the south/east side of the bridge, exits roughly at N 30 23.370 W 097 54.346. You can bushwhack down to stream level from there, or go to parking at the old low water crossing (N 30 23.390 W 97 54.635) and follow trails up the river. The Low Water Crossing Road continues up the West/North side of the Colorado River for more sights of the dam.
Lakeside views of the dam are best from Mansfield Dam Park N 30.23.795 W 097 54.449 (there is a fee for park use). At the EXTREME drought time of this writing, the “Sometimes Islands” are actually the “Occasional Peninsula” – you can actually WALK out into the “center” of the lake. This affords some fascinating historical views of the terrain “pre-lake,” as well as odds and ends of construction and nearly three quarters of a century of flotsam and jetsam.
Perhaps the most famous lakeside panorama of the dam is from the cliff-hugging decks of The Oasis (N 30 24.335 W 97 52.449).
And, of course, you can boat to some nice lakeside views.
Be sure to describe where your shot was taken and write a decent log!
Just some FAQs (courtesy LCRA (
visit link)
FYI: MANSFIELD DAM
Construction: concrete gravity with earthen (rock) wings.
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
DETAILS ON LAKE TRAVIS
Lake area: 19,297 acres
Elevation when full: 681 feet above mean sea level (msl)
Volume when full: 1,134,956 acre-feet
Historic high: 710.44 feet above msl on Dec. 25, 1991
Historic low: 614.18 feet above msl on Aug. 14, 1951
Target operating range: at or below 681 feet above msl
100-year flood level at dam: 722 feet above msl
“MYTH VS. REALITY - LCRA dams form the Highland Lakes” (
visit link)
Myth:
The Highland Lakes dams will protect downstream homes and businesses from flooding.
Reality:
Mansfield Dam, which forms Lake Travis, is the only dam that was built to hold back floodwaters. The other dams help manage the flow of floodwaters as they travel through the chain of lakes. A severe flood can exceed even Lake Travis' flood storage capacity and cause flooding downstream.
For more background, see:
Photos – LCRA Archives “Mansfield Dam” (
visit link)
LCRA's Historic Moment: History of the Highland Lakes (
visit link)
The history of LCRA Early years and first critical test (
visit link)
LCRA as discussed by Wikipedia (
visit link)
LCRA dams form the Highland Lakes
Structures designed for flood management, water supply, hydroelectricity (
visit link)
Mansfield Dam Wikipedia (
visit link)
Lake Travis Chamber of Commerce history (
visit link)
Texas State Historical Association The Handbook of Texas Online:
Lower Colorado River Authority (
visit link)
‘Handbook of Texas Online: Lake Travis (
visit link)
Lake Travis (
visit link)
LakeTravis.com Lake History (
visit link)