9
THE AUSTIN DAM.
By THOMAS U. TAYLOR.
INTRODUCTION.
Austin, the capital city of the State of Texas, is situated on Colorado River, about 200 miles from its mouth at the Gulf of Mexico. The drainage area of this river above the city is 37,000 square miles. The position of the city of Austin with relation to the watershed is shown in fig. 1. This watershed extends from relatively humid regions in the vicinity of Austin westerly into the subhumid or semiarid Staked Plains. From 1856 to 1881 and from 1885 to 1899, inclusive, a period of forty-one years, the rainfall at Austin averaged 32.52 inches, as is shown by the table on page 32. The rainfall over the entire watershed maybe assumed to be about two-thirds of this, or approximately 20 inches annually.
A water power was created on Colorado River a short distance above the city of Austin, as related in the following pages. After the dam was completed the project was found to be only partially successful, as the amount of water in Colorado River fell far short of the original predictions. There was at the inception a lack of hydrographic knowledge, especially in regard to the minimum flow of the river, and other information, now known to be vital to the proper location of the dam, was not obtained. Finally, during the great flood of April 7, 1900, the dam was destroyed, with great loss of life and property.
From measurements taken in March, 1890, it was concluded that the minimum flow of Colorado River was 1,000 cubic feet per second. Upon this basis, and upon the assumption that this minimum flow would be held back nights and Sundays and utilized only sixty hours a week, it was concluded that the flow over the Austin dam would develop more than 14,000 horsepower. The city's demands were placed at 2,000 horsepower, and it was the intention to sell to manufacturers the surplus of 12,000 horsepower.
On May 28, 1896, when power was being furnished for pumping, for city lighting, and for city motors, the level of Lake McDonald "
The Colorado River of Texas should not be confused with the Colorado River of the West, which is formed by the junction of the Grand and Green rivers in eastern Utah, flows southerly through gigantic canyons, and finally empties into the Gulf of California.