KNOXVILLE, Tenn. — An earthen-dam break sending damaging flood waters through a small New Hampshire town demonstrates the need for reinspection of private dams, a University of Tennessee civil engineer said Wednesday.
The town of Alton, N.H., is cleaning up from the Wednesday flood which damaged some homes and many vehicles, tore up a quarter-mile section of highway and left one woman missing.
The dam, built on private property to protect low-lying areas from hillside runoff, was rebuilt several years ago. The lake it formed covered about 15 acres.
“Efforts to maintain, inspect and regulate private dams is an on-going process,” Dr. Bruce Tschantz said.
“Dams, like people, need inspections, health checkups periodically. For the high-hazard dams, the health checkup should be once every year. Other dams should be inspected every three to five years,” Tschantz said.
High-hazard dams are those with the potential to kill people or cause major damage downstream, he said.
“You can pass laws and regulate dams, you can inspect them, but it takes constant surveillance (to prevent a dam break).”
Tschantz, a UT-Knoxville professor, was a White House consultant on dam safety in the late 1970s. A report he submitted said private dam failures between 1972-77 resulted in the loss of nearly 500 lives and $2 billion in property damage.
While that report was on the president’s desk, a dam in Toccoa, Ga., broke and its flood waters killed 39 people. A dam break above Estes Park, Colo., in 1982 killed four and caused an estimated $36 million in damage. Three years later the town of Fort Payne, Ala., was evacuated because a dam broke.
“States are beginning to get a handle at least on the inventory,” Tschantz said. “What’s lacking is inspection of every dam. With a lack of money, they inspect those which can cause the largest problems first, the high-hazard dams.
A Corps of Engineers study in 1982 revealed 2,900 unsafe dams “which posed a threat to human life,” said Tschantz.
A follow-up UT-Knoxville study in 1985 listed 80,000 private dams nationwide, of which 1,948 private dams were unsafe — meaning they were improperly designed, have deteriorated to a dangerous condition, or could not adequately contain flood waters.
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Contact: Dr. Bruce Tschantz (423-974-7721)