A STUPENDOUS PROJECT.

Otago Daily Times, Issue 18861, 14 May 1923, Page 12

A STUPENDOUS PROJECT.

HOW AMERICA DOES THINGS.

A WALL OF WATER 700 FEET HIGH; 150 MILES LONG. 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, at least in the east, commensurate with its vast importance. Seven States lying within the great basin of the Colorado River are combining efforts in order tp 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 lands in the region of the famous Imperial Valley of southern Caliornia 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 wellknown Grand Canyon National Park, another something over 100 miles below it, at Boulder Canyon, oh the border of Nevada. These two will bo capable of backing up and holding every drop thac flows 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 snows 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 turbulent stream during so long a period of time. Nor will it be any easier to picture a wall of rock extending a fifth of a mile from side to side and standing nearly as high as the Woolworth Tower. The highest of these two dams will be exactly double the height of tbs highest similar structure already in existence, and will stand 700 ft above the normal level of the river. It will impound 80 times as much water as the Asnokan Dam and 36 times as much as the famous Assouan Dam of Egypt. A SAFE AND SENSIBLE PLAN.

One gasps at the disastrous possibilities in case such a dam should burst, loosing on the land below a wall "of water 700 feet high and ISO miles in length. The answer is that those 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 wore simply straight barrages thrown across the stream. Such structures cannot have a fraction of the strength possessed by the “recumbent arch” dam. This, leaving an outline curved or bowed .in an upstream direction, requires in order to move it not merely sufficient force to tip 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 dams exist, for following the initial filling of the reservoirs the usual excess of water will continue to flow through the canyon as before.- while neither dams or reservoirs will encroach one inch on the area of the Grand Canyon National Park. While it is the intention of the commission appointed K- the seven States involved to award full priority of_ right to the use of water for agriculture, it will be possible, in addition, to generate in the entire basin over 6,(KK),00f) of electrical horse-power. This giant proposal a great host of legal ramifications and political influences, yet it is to the credit of the seven States involved —namely, Arizona, New Mexico, Colorado, Nevada, Utah, Wyoming, and California—that long and costlv litiiration is being replaced by mutual study and concession. A commission has teen appointed consisting of members from each State involved. meeting with representatives of the Federal Government. The chairman of the commission is Herbert Hoover, who, himself an engineer, is endeavouring to brino- about, a mutnallv satisfactory solution of the problem and to set in motion the actual work of this ’•roiect. which should bring within the control of man the last outpost of that indefinite Western ' area which was labelled on the school book maps of our fathers, “The Great American desert, valueless.”