PUMPING ON THE COLUMBIA BASIN PROJECT

PUMPING PLANT AT THE DAM

The balancing reservoir in the Grand Coulee, to which all irrigation water for the Columbia Basin Project is to be pumped, will be nearly 660 feet above the low-water level of the river. The dam will raise the water to about 355 feet and pumps will lift that required for irrigation the rest of the way.

A conveyor 5,965 feet long carries washed sand and gravel from screening plant to stock piles at the dam

The pumping plant will be located on the west side of the river, behind the dam, within the reservoir basin. There will be installed ultimately 12 pumps, each with a capacity of 1,600 cubic feet per second. Two of the pumps are regarded as "spares," the normal capacity of the pumping plant being 16,000 second-feet. Each pump would be able to take care of the domestic water requirements of nearly 7 million people. One pump will elevate sufficient water to irrigate 120,000 acres of land.

Directly connected to each pump will be a 66,000-horsepower synchronous motor, two motors being supplied with power directly from one generator in the power plant. Generator and motor speeds will be adjustable to the most efficient pump speeds at various heads. Ordinarily, pumping will be against a 280-foot head; that is, from a full storage reservoir behind the dam to a full balancing reservoir in the Grand Coulee.

Pumps will discharge through conduits 13 feet in diameter and about 800 feet long into a canal leading to the balancing reservoir in the Grand Coulee about 1.7 miles away.

Bulk cement unloaded from boxcars by a machine that blows it through hose and pipe—as much as 60 cars a day

AUXILIARY PUMPING PLANTS

Of the 1,200,000 acres of land in the project, 980,000 acres will be watered by gravity from the system of canals extending southward from the balancing reservoir. A total of about 220,000 acres of irrigable land is about 70 feet above the gravity canal system. Auxiliary pumping plants will be constructed to serve such plants as the project develops, power for them being derived from auxiliary power plants at canal "drops" on the project lands.

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