A public-private task force of dam safety experts now estimates that $40 billion is needed to repair and upgrade U.S. structures. That has prompted its parent organization, the Association of State Dam Safety Officials, to begin developing state-by-state cost estimates and a national funding program.
The group held its annual meeting in Providence, R.I., Sept. 28-30 and is moving on several fronts to develop a national dam safety effort. A basic problem owners face is finding money for repairs and improvements, or simple maintenance.
Dams can fail in a number of ways, primarily through seepage and piping and overtopping. "Very often owners need to increase spillway capacity to pass floodwaters, or the dam will overtop and could fail," says Eugene P. Zeizel, engineer for the Federal Emergency Management Agency's national dam safety program. "This is an expensive and difficult operation, and along with seepage, is one of our greatest concerns."
The association estimates 58% of all dams are privately owned, and many of these are among the 20 to 50 dams that fail annually. "We can't afford not to do something," says Alton P. Davis Jr., a West Ossipee, N.H., engineering consultant. "We are trying to figure out what it would take to fix the problem."
To develop the $40-billion number, the task force segmented the estimated 75,193 federally inventoried dams into four height groups. They then determined percentages for specific actions such as maintenance, detailed engineering assessment, hazard potential reclassification and physical improvements. Each action was assigned estimated costs. Dams of 25 ft and higher needed about $31.5 billion worth of upgrades.
"For us to be successful as regulators we must go beyond just identifying problem dams," says Raul F. Silva, task force chairman and Massachusetts Dept. of Environmental Management chief engineer. "A fund must be developed for a combination of loans and grants to adequately address their problems." He says several states, such as Pennsylvania, Wisconsin and Utah, have existing funding programs. "There are more rehabs in Pennsylvania in one year than we have in five years in similar states without a program," he says.
Dam safety officials also are pushing programs to raise awareness of dam risks. One current problem is that no one really knows how many dams exist in the U.S. The 75,193 included in the Corp of Engineers' national inventory is significantly less than the 94,000 generated by a tally of state inventories. "And, you can probably add another 10,000 to 15,000 that are not jurisdictional," says Davis. Massachusetts has 1,528 dams in the national inventory but 2,921 under state regulation.
Dams less than 25 ft high with less than 50 acre-ft of storage are often not regulated. "Smaller dams become a greater concern following downstream development and because they are inspected infrequently," says Silva. "But in the intervening time they could go from low to high hazard and the homeowners and inspectors would know nothing about it." New Jersey last month ordered new inspections of hundreds of its 1,592 listed dams, after a freak August flood in two counties breached four and damaged 20.
Currently about 1,800 dams are labeled "unsafe." Another 9,300 are labeled "high-hazard"meaning a failure could result in loss of life. "Without a national program we could have a serious problem," says Zeizel.