This continuing argument against dams in general, focuses on the particular ones that all agree are problems, the small mostly privately owned dams that, once their usefulness has been outlived, need to be dismantled.
The major public dams: Hoover, Shasta, Grand Coulee, etc. serve important public functions and are still the only method devised to store water, protect from major flooding on rivers—like the American—that flood during rainy season, and generate clean power in the process, that human beings have come up with.
But, unfortunately, this generalizing type of argument, using small and mostly private dams to speak out against all dams continues a great disservice to a public needing more water during the dry times, protection from it during the wet, and power from it all the time.
Jacques Leslie: Our aging dams
By Jacques Leslie -
Published 12:00 am PST Tuesday, January 23, 2007
SAN FRANCISCO -- When the 40-foot-high Kaloko Dam collapsed on the Hawaiian island of Kauai last March, its reservoir released a 70-foot-high, 200-foot-wide, 1.6-million-ton wave that carried away 16 cars, hundreds of trees and a cluster of houses, drowning all seven occupants. At least two bodies were swept three-quarters of a mile to the ocean; four were never recovered.
It is tempting to dismiss Kaloko's collapse as an isolated event, but given the perilous state of the nation's dams, it is more likely a harbinger. In 2005, the American Society of Civil Engineers gave U.S. dams a D, a grade that is still justified two years later.
For starters, the nation's dam stock is rapidly aging. Most dams need major repairs 25 to 50 years after they're built, and most U.S. dams are at least 25 years old; some, like the 116-year-old Kaloko, were built more than a century ago.
As dams age, their danger increases. This is a matter of not just advancing decrepitude, but "hazard creep" -- the tendency of developers to build directly downstream from dams, in the path of floods that would follow dam failures. The result is that even though Americans now build few dams, more and more dams threaten people's lives. Chiefly for this reason, the number of dams identified in one estimate as capable of causing death and in need of rehabilitation more than doubled from 1999 to 2006, from around 500 to nearly 1,400. The civil engineers' 2005 report placed the number of unsafe dams much higher, at more than 3,500.
On top of that, dam safety officials are so overworked that in most states, they don't come close to carrying out all the inspections required by law. According to the engineers' society, the average state dam inspector is responsible for 268 dams; in four states the number exceeds 1,200. It is no coincidence that even though Hawaiian law requires dam inspections every five years, Kaloko was never inspected.
We don't even know how many dams the country possesses. Using one set of criteria, the National Inventory of Dams, maintained by the Army Corps of Engineers, places the number at 79,777, while the sum of dams inventoried by the states is more than 99,000. Even that number is questionable, since it includes suspiciously low counts from several states. In addition, state officials are constantly discovering previously uncounted dams during routine inspection trips. And if the definition of dams is broadened to include the smallest ones, the estimates are as high as several million.
Unlike, say, waterways and sanitation plants, a majority of dams -- 56 percent of those inventoried -- are privately owned, which is one reason dams are among the country's most dangerous structures.
