Overview

Inks Lake (also known as Roy Inks Dam) is located about ten miles west of Burnet in Burnet and Llano counties, Texas, on the Colorado River. The lake is owned and operated by the Lower Colorado River Authority for hydro-power generation and recreational purposes, together with other Highland Lakes as a system. The lake and dam are named after Roy B. Inks, one of the original directors on the Lower Colorado River Authority Board. Construction on the Dam, started in 1936 and was completed in 1938.

Devil's Waterhole at Inks Lake State Park.

The dam is a concrete gravity structure of 1,547.5 feet long with a maximum height of 96.5 feet. The top of the dam is at an elevation of 922 feet above mean sea level. Although the 100-year flood level is 901.7 feet above mean sea level, the dam is standing well at recorded flood peaked at 902.8 feet above mean sea level on July 25, 1938. The uncontrolled emergency spillway is located at the concrete gravity section of the dam with its crest at elevation of 888.3 feet above mean seal level. According to the TWDB 2007 survey, the lake has a capacity of 14,074 acre-feet encompassing a surface area of 788 acres at normal pool elevation of 888.22 feet above mean sea level. The drainage area is 31,290 square miles, of which 11,900 square miles is probably noncontributing. The lake is considered to be constant-level because the normal turbine discharge is coordinated with the inflow from Lake Buchanan so that normal fluctuation is small. However, during periods of floods the lake level varies considerably.

History

The idea of the Highland Lakes chain originated in the mid-19th century. The credit for the idea of a dam on the Colorado may go to Adam Rankin Johnson, a farmer and entrepreneur who established the city of Marble Falls. In 1854 he marked an “X” at a location where one of the dams should be built.

Johnson secured the water rights for a multi-dam project but never developed his idea. He eventually sold his rights to C. H. Alexander, Sr. In 1909 he began construction of a dam near Marble Falls but was able to build only one-third of the structure before his money ran out.

Downstream, the City of Austin briefly succeeded in building the first dam across the Colorado. That structure lasted only seven years before being destroyed by a catastrophic flood in 1900. The city had barely finished rebuilding the dam in 1915 when it was again heavily damaged by floods.

1900 flood event that destroyed the original dam

It was not uncommon for the bankruptcy of dam builders to result in the creation of the LCRA. In the 1920s, catastrophic floods across the United States, coupled with the construction of massive Boulder Dam in the West, increased national interest in dam projects that coupled hydroelectric power generation with flood control. That led to one utility company in 1931, which had purchased Alexander’s rights, to begin building a massive structure on the Colorado at the location marked by Johnson. But a year later, less than halfway through construction, the company went bankrupt, a victim of the Great Depression and corporate mismanagement.

Sources:
http://www.hillcountrynews.com
https://texashistory.unt.edu/
http://kxan.com/blog/2010/04/07/tom-miller-dam-turns-70/
Image: https://en.wikipedia.org/wiki/Stovepipe_Johnson

Statistics

  • Primary Purposes: Hydroelectric Power
  • Location: Burnet and Llano counties
  • Construction Dates: 1936 to 1938
  • Lake Area: 777 acres
  • Lake Capacity: 13,668 acre-feet
  • Full Elevation: 888 mean sea level (msl)
  • Historic High: 902.8 feet msl on July 25, 1938
  • Historic Low: 877.1 feet msl on Dec. 6, 1983
Dam Statistics
  • Dam Dimensions: 96.5 feet high , 1,547.5 feet long
  • Spillway Elevation: 888.3 feet above msl
  • Top of Dam: 922 feet above msl
  • Total Discharge Capacity:
    3,400 cubic feet per second (cfs): 1 turbine at 3,400 cfs
Current Conditions

View all current conditions at waterdatafortexas.org

Construction Begins on the Highland Lakes

In the 1920s, catastrophic floods across the United States, coupled with the construction of massive Boulder Dam in the West, increased national interest in dam projects that coupled hydroelectric power generation with flood control. One utility company that had purchased Alexander’s rights , began building a massive structure on the Colorado. But just a year later, less than halfway through construction, the company went bankrupt, a victim of the Great Depression and corporate mismanagement.

The abandoned dam passed into the hands of Alvin Wirtz, a savvy attorney and former state senator who eventually secured the promise of federal funds if a state agency could be created to finish the project. Thanks to his influence, the Texas Legislature eventually created LCRA in November 1934.

Possessed with the defunct utility’s properties and fortified with $20 million in federal grants and loans, LCRA resumed construction of what eventually became Buchanan Dam and a companion project, Inks Dam, downstream. The work provided hundreds of jobs to depression-stricken families.

Completed in 1938, the two dams were designed to offer the hydroelectric production and flood protection that the project’s originators had promised. The water in Lake Buchanan would provide the “fuel” for the Buchanan Dam powerhouse, and the dam sported 37 floodgates to moderate the release of Hill Country floodwaters. As waters from Buchanan flowed into Inks Lake downstream, Inks Dam would discharge the flows through its own powerhouse, increasing the waters’ hydroelectric output.

With Buchanan and Inks dams completed, Mansfield Dam was planned for additional flood protection.