by Whit Gibbons

September 19, 2004

As we are all aware, hurricanes cause flooding, and flooding sometimes breaks dams. When that happens, we usually blame the upstream rains. But should we also blame anyone who supported building the dam without objective and critical review of the costs as well as benefits?

River dams are often viewed as positive for a region. In support of dams is the fact that Hoover Dam and the Aswan High Dam were once voted among the world's Top Ten Construction Achievements of the last century. The fact that the concrete industry took the poll probably had some impact on the rankings.

Nonetheless, Hoover Dam, aka Boulder Dam, on the Colorado River is a good starting point for positive features of dams. Hydroelectric power can clearly be an asset. The creation of recreational reservoirs, like Lake Mead, is viewed as positive. Downstream flood control of agricultural areas has also been given as a reason for building dams, as with the development of the Imperial Valley below Hoover Dam.

However, not every citizen views even Hoover Dam as in the best interest of the natural environment. Some dam critics question whether the benefits, not only of building dams but also of keeping all the ones we have, warrant the environmental costs. Many ecologists feel that dams on big rivers have put numerous animal species in peril.

In the spirit of challenging dam building, consider the recreational opportunities created. Some people, including hunters, hikers, and bird-watchers, would get far more recreation from 50,000 acres of woodlands and small wetlands than from the same amount of boring open water. Why have we never stopped to think that more people enjoy woods than reservoirs? I do not suggest the elimination of all artificial lakes and reservoirs, only that we consider what would serve us best.

One line of political illogic that does little to support dam building is that not building a dam can cost jobs. The argument was used at Tellico Dam where construction was delayed by the presence of the snail darter, a little fish thought to be endangered. Creating jobs is no excuse for building a dam with government tax money. We could create jobs equally well by removing dams. Dam deconstruction would mean jobs for people to build new roads in the drained area and to replant the forests.

The major strike against dams is, of course, the environmental costs. Fish such as river sturgeon that swim up and down rivers have their geographic range abruptly truncated by a dam. For fish like American eels and salmon that spend part of their life in saltwater and part in fresh, encountering a dam can be serious. In addition, the changes in flow patterns, increased siltation and turbidity, and fluctuating water levels have been shown by numerous ecological studies to cause severe disruption to the river habitat.

Why do we accept the negative consequences of dam building when positive returns seem minimal? I think much of the problem rests with pork barrel politics, a process that has seldom served the country as well as it has the pocketbooks of local politicians and their friends. And once a dam project is approved in Congress, bureaucratic inertia sets in. Halting construction, even though the negative aspects far outweigh positive returns, is an unlikely scenario.

I am sure not everyone will agree that dam building has few redeeming qualities. Some people would mention flood control for urban areas, a commonly used excuse for constructing dams. But does an upstream dam really protect the floodplain of a river from flooding? Do we really have many dammed rivers that have not also had flooding disasters downstream? Do dams simply delay the economic disasters of major floods rather than prevent them forever? Ask the people downstream who have survived a broken dam if the trauma was worth the protection offered against a few years of minor flooding. Is the protection-from-flooding feature attributed to river dams simply another public acceptance without objective evaluation of the true worth?

Reconsidering the whole process associated with constructing river dams would be healthy. Should we stop building any more and even remove a few already in place? After all, removing some dams would create jobs, not to mention making for healthier river ecosystems.

If you have an environmental question or comment, email

(Back to Ecoviews)