Word: dams
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Dates: during 1950-1959
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Viewed from the canyon's high rim, the dam looks too small to create, as it will, a patch of mottled green land nearly as big as Connecticut. But all modern irrigation dams look small when compared with what they do. They accomplish their ends by geographical judo, playing on the weaknesses of their rivers...
Grand Coulee Dam is the biggest dam anywhere. Viewed from the gorge below, it looks like the biggest thing on earth. Over its spillway, 1,650 feet wide, the great Columbia River sweeps majestically, a curve of green water up to 17 feet thick. It falls so far (320 feet, twice the height of Niagara) that it seems to fall slowly. The roar of the falling water, though loud, is as smooth as the sound of surf on a distant beach...
Displaced River. A dam high enough (more than 600 feet) to turn the Columbia directly into the Coulee would have backed the water far into Canada. So the dam was built to raise the water level about 350 feet. A small part of the electric power that its turbines generate is used to pump part of the river the rest of the way (280 feet) and spill it into the Coulee. This turbine-pump combination, using a river's energy to raise part of its water over its own high banks, is the key engineering trick that frees irrigation...
Moving the Rain. Shasta Dam, second highest in the world, now blocks the upper waters of the Sacramento, storing 4,500,000 acre-feet * of water. During the almost rainless summers, this water will be fed into the Sacramento. When it reaches the delta where the Sacramento and the San Joaquin join, it will be led across the lowlands to a pumping plant at Tracy, in the foothills of the Coast Range. There it will get a boost from six huge pumps to lift it 200 feet into a canal. The pumps run on power from Shasta Dam. At Tracy...
From Tracy, the boosted Sacramento water will wind south 117 miles and spill into the San Joaquin at Mendota Pool. Then it will run down the San Joaquin, irrigating downstream lands. The payoff comes at the extreme southern end of the Central Valley. Friant Dam will divert San Joaquin water that would otherwise be needed downstream and send it through a 153-mile canal to drought-plagued Bakersfield. No Sacramento water will actually get to Bakersfield, but the effect will be just the same. As the bureaumen put it: "The rain will move 500 miles south...