Monday, January 22, 2007

Dam Busters: On the Cost of Repairing US Dams

This post follows a couple of previous posts we did on the economics of dams following a recent working paper about dams in India (forthcoming QJE??).

Climate Change in Africa: Shrinking lakes and the role of dams

Economics of dams in Brazil

The New York Times article below is written in the light of a recent dam collapse in Hawaii and is concerned with the shocking state of dam infrastructure in the US. What about the situation in less developed countries? What was a surprise was just how large the percentage of dams that are privately owned is. A cautionary tale indeed.

Before the Flood

In 2005, the American Society of Civil Engineers gave United States 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 United States 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.

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. Many private owners can’t afford to repair aging dams; some owners go so far as to resist paying by tying up official repair demands in court or campaigning to weaken state dam safety laws.

Thousands of dams have been abandoned by their owners, and over time, title to them has become obscure — 12 percent of the dams in the Army Corps of Engineers’ inventory have no known owner. As these dams become dilapidated, the states are left with the expensive task of repairing or dismantling them. Privatization advocates, take heed: this is a cautionary tale.

Climate change will also make dams more dangerous by increasing precipitation in many parts of the country, thus undermining the flood assumptions that underlie dam designs. Consider that in October 2005 and last May, two strong but hardly cataclysmic New England rain storms caused the overtopping or breaching of more than 400 dams in three states; a much fiercer storm would compromise far more dams, worsening flooding and potentially endangering thousands of people.

OK, so things have slipped a little. Surely dangerous dam can be repaired quickly and efficiently so as to potentially save many human lives?. What do the economists/engineers say?
The American Society of Civil Engineers estimated in 2005 that repairing dams threatening human life would cost $10.1 billion, while a 2003 study by the Association of Dam Safety Officials placed the cost of repairing all non-federally owned dams in the national inventory at $36.2 billion. In the last session Congress considered legislation to repair dams at a rate of $25 million a year for five years, but even that feeble gesture didn’t make it out of committee.

1 comment:

Biopolitical said...

A cautionary tale indeed. The reason dams become dilapidated is that rivers are not in private hands.