Word: dams
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...Edwards and Embrey dams (each hundreds of feet long and more than 20 ft. high) are among the most imposing structures that America's dam busters have tackled to date. But while a handful of large dams are scheduled to come down soon, those involved in their demolition are proceeding with caution, wary of what hazards they might unleash. As University of Utah political scientist Daniel McCool puts it, "We don't know how to remove big dams yet. We're still learning...
What about even bigger, more significant dams? Well, no one has seriously suggested demolishing the Grand Coulee Dam on the Columbia, but a coalition of environmental groups has taken aim at four dams on the lower Snake River--and stirred up a storm of controversy. The damage those dams have done is clear. Since they were built in eastern Washington State from 1955 to 1975, the salmon population in the Snake has gone into free fall. But the benefits the dams provide are also clear: inexpensive barge transport for wheat farmers, irrigation water for fruit growers and a small...
...then there's the Glen Canyon Dam on the Colorado, which after its completion in 1963 not only robbed the Grand Canyon of sediment needed to rebuild sandbars and beaches but also drowned a spectacular landscape far bigger than the Hetch Hetchy Valley. Thanks to a multiyear drought that has only recently eased, the landscape has begun to re-emerge, energizing an effort by the Glen Canyon Institute to correct what conservationist David Brower called "America's most regretted environmental mistake." It's bound to be an uphill battle. The Glen Canyon Dam is part of the seven-state Colorado...
...what if the benefits provided by such dams could be replaced? Would that make their removal politically palatable? In a thick report on Hetch Hetchy released last fall, Environmental Defense argued that there are alternative ways to provide both the water and the power currently supplied by the O'Shaughnessy Dam. In one scenario, for example, the San Francisco Public Utilities Commission would shift its water storage over to the Don Pedro Reservoir, lower down on the Tuolumne River, which feeds the Hetch Hetchy System. But that could be tricky. Don Pedro belongs to the Turlock and Modesto Irrigation Districts...
...cost of retrofitting the Hetch Hetchy system, and who would pay for it, are other sticky issues. The total price tag for replacing the water and power that the O'Shaughnessy Dam provides, according to Environmental Defense, ranges from $500 million to $1.5 billion. The San Francisco Public Utilities Commission believes that the cost will be far higher, however--at least $8 billion if removal of the dam is included. Either way, it's a big chunk of change. By contrast, the cost of removing the Edwards Dam was just $3 million; it is estimated that taking out the Elwha...