GIGANTIC DAM PROJECT.

New Zealand Herald, Volume LXVI, Issue 20355, 9 September 1929, Page 13

GIGANTIC DAM PROJECT.

HIGHEBT JN THE; WORLD*

EIGHTY MILLION POUNDS.

STUPENDOUS COLORADO SCHEME. [from our, own correspondent.] SAN FRANCISCO, Aug. 21. A gigantic project, second only to the Panama Canal, but one of the vastest in the United Slates because of its more direct benefit to the individual, is now under way in the construction of the Boulder Dam and Canal, to cost £80.000.000. The vital centre of the south-west is a narrow gorge in the Colorado River, about 100 miles below the Grand Canyon. Here the huge dam will be erected to harness the mighty river that makes a thousand turns in 30 miles of its course.

President Hoover has issued a proclamation, sealing a compact between six of the seven States in the Colorado River basin. An unsettled dispute between Arizona and California as to mutual interests in the undertaking is not regarded as likely to last long. The project had its genesis in everrecurring danger to the settlers of the Yuma and Imperial Valleys and territories adjacent to the river. In the Imperial Valley are 60,000 people. It is a huge inland basin, extending about 100 miles north from the Mexican line, and is entirely below sea-level. It is cut off from the sea, or Gulf of California, by a delta formed of silt washed down by the Colorado River. This silt, which constantly comes from tho upper reaches of the river, is one of increasing dangers ■Which the project will eliminate. A huge system of levees is the only thing that keeps the river from broaching the Imperial Valley. These levees have now reached the danger point in height, and disaster is presumably only a question of time.

The dam will rear itself to nearly twice the height of any dam-in the world. The great lake to bo impounded will hold several times the quantity of water of the great Assouan Dam, on the Nile. There will be four diversion tunnels, each 50ft. in diameter, and three miles long, to divert the water during construction. Two coffer dams are to be erected. The work is expected to occupy seven years. The total height of the dam will bo 600 ft. Before it reaches half that height, it can be operated to control flood, regulate irrigation flow, and develop several hundred thousand horse-power for hydro-elec-tricity. It will irrigate 3,000,000 acres of tillable land in Nevada, Arizona, California and Mexico.

Some of the costs are stupendous. The dam and power plant will run to £33,000,000, the aqueduct to £30,000,000, power house and lines £15,000,000, canal £6.000,000, and water impounding £5.000.000.

Enormous new wealth will be developed in the south-west from the cheap power and water provided. Los Angeles, whose water comes by ducts extending for 250 miles across the desert, is looking for tremendous benefit from the dam. Following the discovery of gold, then oil, Boulder Dam is placed as the third milestone in California's history.