Tom Miller Dam, which turns 70 years old this April 6, sits atop the site of one of the most dramatic moments in Austin's history: the destruction 110 years ago of the original Austin Dam.
The original Austin Dam, completed in 1893, was featured on the cover of Scientific American magazine. In the background is one of the steamboats that provided cruises on the lake. (LCRA Corporate Archives W00693)
Catastrophic floodwaters on April 7, 1900, destroyed the dam as well as one of Austin's earliest civic booms. Subsequent floods in 1915 heavily damaged a rebuilt dam, which was left in disrepair for more than two decades until LCRA constructed the present-day dam. Tom Miller is one of the six dams built by LCRA that form the Highland Lakes.
LCRA, which opened for business in 1935 to put the lower Colorado River to more productive use, is celebrating its 75th anniversary this year.
Completed in 1940, Tom Miller Dam sits atop the remains of its two predecessors. Downstream in Lady Bird Lake, one can still see rubble from the original dam, a reminder of Austin's early glory days – and the destruction that can be wrought by uncontrolled floodwaters.
Original Austin Dam completed in 1893
Massive floodwaters in April 1900 pushed out this section of the Austin Dam, destroying the structure. The floodwaters also drowned 18 people and destroyed 100 houses, causing more than $1 million in damages. (LCRA Corporate Archives W00514)
The idea for the Austin Dam was born in 1871 and became the focus of municipal elections in 1889 out of a familiar civic concern – ensuring the city's continued growth and economic prosperity.
Dam proponents feared Austin had plateaued as a government and university town and was being bypassed by the state's oil boom. They claimed building the dam would attract new industry by offering hydroelectric power. Even better, the city could break free of the local utility that was charging, by the Austin Statesman's estimate, roughly five times the cost of delivering water and power.
Citizens elected as mayor the pro-dam candidate, John McDonald. The following year, the city sold $1.4 million in bonds for the project. One supporter wrote a theme song: "We'll dam the Colorado, yes, yes, yes, yes," ran one lyric. "Then shout and sing and let our voices ring for the Dam, Dam, Dam."
The Austin Dam was completed in 1893 and the power house two years later. It was the first dam built across the Colorado River and – according to the press hype of the day – the largest dam in the world.
By today's standards, the dam was unremarkable – a wall of granite and limestone, 65 feet high and 1,100 feet long, with no catwalk or floodgates. But Scientific American magazine was sufficiently impressed to feature the dam on its cover.
The city wasted no time in finding uses for its new source of electricity. It installed 31 moonlight towers – 165-foot-tall structures that manufacturers promised would keep the community of 20,000 bathed in light throughout the night.
(The moonlight towers may have been Austin's first environmental controversy. Residential gardeners feared the "eternal moonlight” from the towers would cause corn and bean stalks to grow round the clock, so tall that the gardeners would have to saw the plants down.)
The city built a rail line, with electric trolley cars, to transport residents to the dam and its reservoir, Lake McDonald, named after the mayor. (It is now Lake Austin.)
Lake McDonald became a popular attraction. Steamboats like the Ben Hur, a three-story sidewheeler, provided cruises of the lake, along with dinner, dancing and vaudeville shows. Watercraft enthusiasts canoed, sculled and sailed. Other attractions included a giant diving tower at the Ben Hur wharf and a grandstand and pavilion for musical performances.
But the promised economic boom never materialized. Worse, the Austin Dam was plagued by problems from the start. The structure was built on a fault line that allowed water to seep. Silt had filled nearly half the lake by February 1900. And the dam's design failed to accommodate the force that could be created by a large volume of water.
Catastrophic flood brought death, destruction, economic woes
The second Austin Dam was damaged by floods in 1915. The dam went unrepaired for more than two decades and remained vulnerable to heavy floods. Here, a houseboat flows over the top of the dam during a June 1935 flood. (C08484-A Austin History Center)
All of this set up the dam for its fatal blow when a five-inch rain fell in the Austin area on April 6, 1900, along with heavy rains in the Hill Country. With no upstream dams to capture runoff, the Austin Dam was defenseless against the resulting flood wave, which one eyewitness estimated at 25 feet high and a mile wide.
At 11:20 a.m. on April 7, the floodwaters crested at 11 feet atop the dam before it disintegrated, with two 250-foot sections – almost half the dam – breaking away. The flood also damaged the power house, drowning five workers, and destroyed the Ben Hur.
In all, the flood drowned 18 people and destroyed 100 houses in Austin, at a total estimated loss of $1.4 million, in 1900 dollars.
The destruction saddled Austin with heavy debt from the dam bonds, and the city curtailed its public services. By 1905, according to the Handbook of Texas, Austin had few sanitation sewers, virtually no public parks or playgrounds, and only one paved street.
In 1912, the city began rebuilding the dam, adding floodgates and redesigning the structure to help it withstand floodwaters. But the floodgates, which were only 15 feet wide, became clogged by driftwood during flooding in 1915 as the dam neared completion. The driftwood jammed the gates, and the floodwaters tore out the center section of the dam.
The dam went unrepaired for more than 20 years. It provided one of Austin's most iconic moments when a photographer captured a shot of floodwaters pushing a houseboat over the dam during a massive flood in June 1935.
Two years later, Austin Mayor Tom Miller reached an agreement with LCRA to rebuild the dam a second time.
LCRA completed construction in early 1940 at the same time it was building Mansfield Dam, the giant structure upstream that would eventually protect Austin from the worst of the Colorado River's floods.
Austin and LCRA held dedication ceremonies for the new Austin dam on April 6, 1940 – one day before the 40th anniversary of the destruction of the original dam. Chamber of Commerce officials recommended naming the dam in honor of Miller, and the name stuck.
Tom Miller Dam still in operation 70 years later
The third dam, named for Austin Mayor Tom Miller, was dedicated April 6, 1940 – one day shy of the 40th anniversary of the destruction of the original dam. (LCRA Corporate Archives W00059)
Seventy years later, Tom Miller Dam is still standing. LCRA operates the dam under a long-term lease with the City of Austin that runs through 2020. As one of the Highland Lakes dams, Tom Miller passes through water releases for use by the City and other water customers and generates hydroelectric power for LCRA's wholesale customers.
From 1995 through 2005 LCRA made several upgrades to Tom Miller and the other Highland Lakes dams to ensure that all of them would continue to withstand a "probable maximum flood,” an engineering term for a worst-case flood scenario. Upgrades at Tom Miller Dam included anchoring the structure to the lakebed with steel cables and additional concrete, adding other structural reinforcement, and equipping each of the nine floodgates with its own hoist to expedite opening and closing.