A STUPENDOUS PROJECT

Southland Times, Issue 18938, 11 May 1923, Page 8

A STUPENDOUS PROJECT

HOW AMERICA DOES THINGS. The public has become so accustomed to taking for granted the successful outcome of great engineering feats (says the New York Outlook) that the stupendousness of the Colorado River Basin development as yet scarcely seems to have received attention commensurate with its vast importance. Seven States lying within the great basin of the Colorado River are combining efforts in order to set to work its entire annual flow for the purpose of irrigating millions of acres of arid lands, of generating electrical energy to the extent of six millions of horse-power, and, by means of dams constructed partly for this purpose, of protecting two million acres of valuable ;dnds in the region of the famous Imperial Valley of Southern California from the early threat of destructive flood. In addition to a number of minor dams to be constructed in the head waters of the Colorado, two immense barriers are to be thrown across the canyon at favourable spots where the rock walls are close together, one at Lee’s Ferry, above the well-known Grand Canyon National Park; another something over one hundred miles below it, at Boulder Canyon, on the border of Nevada. These two will be capable of backing up and holding every drop that bows through the river’s channel during more than two years. To those who have seen the river at high-water mark, when swollen by the melting winter snow’s along its scores of mountain tributaries, it doubtless will be a difficult thing to believe that anything smaller than an emptied sea-basin could contain even a fraction of the waters of this tribulent stream during so long a period of time. Nor will it be any easier to picture a wall of rock standing a fifth of a mile from side to side and standing nearly as high as ;he Woolworth Tower. The highest of these two dams will be exactly double the height of the highest similar structure already in existence, and will ,st and 700 ft above the normal level of the river. It will impound eighty times as much water as the Ashokan Dam, and thirty-six times as much as the famous Assouan Dam of Egypt. One gasps at the disastrous possibilities in case the dam should burst, loosing on the land below a wall of water 700 ft high and 150 miles in length. The answer is that dams which have failed in the past have been of a wholly different type of construction. The proposed structures are comparatively short and are perfectly dovetailed into deep cuts made in the unyielding walls of solid rock at their respective ends. The others were long, and often were simply straight barrages thrown across the stream. Sueh structures cannot have a fraction of the strength possessed by the “recumbent arch” dam. This, having an outline curved or bowed in an up-stream direction, requires in order to move it, not merely sufficient force to rip over the stone work, but actually to crush the stones against one another. Will the development injure the Grand Canyon ?

The sightseer on the Bright Angel trail will be unable to gather any visual evidence that the dam exists, for following the initial filling of the reservoirs the usual excess of water will continue to flow through the Canyon as before, while neither dam nor reservoirs will encroach one inch on the area of the Grand Canyon National Park.

While it is the intention of the commission appointed by the seven States involved to award full proprity of right to the use of water for agriculture, it will be possible, in addition, to generate in the entire basin over 6,009,000 electrical horse-power.