Highest Dam in the World
By A. R.
The highest dam in the world has recently been completed in Idaho. It is called Arrowrock Dam. It is a part of a twelve-million-dollar irrigation project. The time estimated as required to build the dam was six years; and the cost, $7,500,000; but it has only been a little over four years since the project was begun, and the cost has only been one third of the estimate. Two million dollars has been saved on the estimate of the entire reclamation system. Before undertaking the work, experts determined, after exhaustive surveys, that enough flood water was going to waste in winter and spring to reclaim and irrigate 240,000 acres. This problem of impounding so large a quantity of water has been completely solved, and the desert will blossom like the rose. From the base of the dam, ninety feet below the normal river bed, to its crest, ten feet above the level of the stored water, it attains to a height of 351 feet. Between the up-stream and the down-stream face, the base of the structure is 247 feet thick. An outstanding engineering feature is the elaborate drainage system within the dam. It is traversed from one side to the other by three galleries, or tunnels, connected by spiral stairways, thus making possible frequent inspections of practically every portion of the dam’s interior. The dam is arranged to handle logs, as there are three billion feet of merchantable timber above the dam, while the mills are below. The device for picking up a log of any size or length, carrying it across the top of the dam, and delivering it into a chute, has a capacity of sixty million feet of timber a year. At this rate, it will take fifty years to exhaust the supply. The government has a railroad running twenty miles out of Boise; and in the four years that it has been conducted, it has earned a surplus of $60,000, taking in $238,000 for freight, and $50,000 for passenger fares.