Tom Miller Dam and Lake Austin

Dam built atop of two earlier structures destroyed by floods

water_miller.jpgTom Miller Dam is leased to LCRA by the City of Austin until December 2020. The dam, built to provide hydroelectricity and store water, creates Lake Austin.

Named for an Austin mayor, the dam was built from 1938 to 1940 atop the remains of two earlier structures, both called Austin Dam. The first was built from 1890 to 1893, and the other from 1912 to 1915. Massive floods destroyed the first dam and heavily damaged the second. The lake originally was called Lake McDonald.

For information on parks on the Highland Lakes, see map of parks and recreation areas.

​FYI: Tom Miller Dam


Location: Travis County, 298 river miles from the Gulf of Mexico
When built: 1938 to 1940
Dam dimensions: 100.5 feet high, 1,590 feet long
Primary purposes: Hydroelectric power, water supply
Generating capacity: 17 megawatts
Top of dam: 519 feet above msl
Spillway elevation: 492.8 feet above msl
Floodgates: nine
Total discharge capacity: 107,700 cubic feet per second (cfs):

  • 4 large floodgates @ 15,300 cfs each

  • 5 small floodgates @ 8,600 cfs each

  • 2 turbines @ 1,750 cfs each


Original name: Tom Miller Dam

Details on Lake Austin


Lake area: 1,830 acres
Elevation when full: 492.8 feet above mean sea level (msl)
Volume when full: 24,644 acre-feet
Historic high: 495.2 feet above msl on May 25, 1981
Historic low: 474.3 feet above msl on Feb. 17, 1963
Target operating range: 491.8 to 492.8 feet above msl
100-year flood level at dam: 493 feet above msl
Dimensions: 20.25 miles long, 1,300 feet at widest point
Original name: Lake McDonald