Fed almost entirely by spring snow melts in the Rocky Mountains, the river was for eons an erratic force of nature, alternately flooding and drying to a trickle, frequently changing course and cutting spectacular canyons along its 1,500 mile route to the sea.
Such a wild, unpredictable river was incompatible with America’s 19th century westward expansion, and after a devastating flood in 1869, the first dam was built to “tame” the Colorado. Completed in 1892, the dam lasted eight years before being destroyed by the insolent river. Before a the dam could be rebuilt, it was destroyed again in 1915.
Not until construction of the monumental Hoover Dam in the 1930s would the river be sufficiently tamed to provide a consistent downstream flow by holding back a massive reservoir known as Lake Mead. Now, more than 20 dams harness the power and flow of the Colorado and its tributaries.
Today’s Colorado River – once powerful enough to carve the Grand Canyon – is one of the most controlled, exploited and contested waterways in the world. Some 78% of its flow is diverted to agricultural use, with the remaining 22% used for municipal and industrial purposes. In most years, there’s so little water left that it never reaches the sea.
Without the various dams, and aqueducts, tunnels, canals, channels and pipelines that control and divert the Colorado, cities such as Las Vegas, Los Angeles, San Diego, Phoenix and Tuscon would not exist as they do today. Neither would the fertile farms of California’s Central Valley, or its famed Imperial Valley, where annual rainfall averages only 3 inches per year.
Demand upon the Colorado River as a source of water in an otherwise arid region has already reached a critical stage. But growing populations, the affects of global climate change, evaporation from dam reservoirs — and massive new water use by the oil shale industry — add up to a future level of demand that simply cannot be met.