Friday, April 17, 2015

Vermont Dams

There used to be a dam right over there, Clark Amadon said, pointing to where the rapids begin, where one of the concrete abutments remained visible.

This was on Cox Brook, not far upstream from where it empties into the Dog River across Route 12 in Northfield Falls. The dam was built in the 1920s, he said, and dismantled in 2007, thanks in part to the efforts of Trout Unlimited and its Vermont Council, which Amadon chairs.

There are two advantages to removing a dam. One, Amadon noted, is that a river and its tributaries comprise a natural system, and getting rid of dams “keeps the systems open” which keeps them healthier.

The other is that a dam taken out by engineers who plan the job will not break apart when no one is watching, possibly destroying property and maybe even someone’s life downstream. No, this does not appear imminent. No Vermont town is in danger of becoming the next Johnstown, PA, where 2,209 people were killed when a dam 14 miles up the Little Conemaugh River gave way in 1899. The big Vermont dams, the ones holding back large impoundments on major rivers, are regularly inspected and effectively maintained.

Vermont has a dam safety law, noted Steve Bushman, the dam safety engineer for the Department of Environment Conservation, adding that if his Department “felt a dam was in imminent danger of failure, we could implement an unsafe dam procedure. We haven’t done that for quite a while.”

But if a mega-tragedy from a breached dam is highly improbable, a smaller but still damaging and perhaps fatal flood is, if not exactly likely, enough of a threat to worry civil engineers.

“There have been quite a few” damaging floods caused by breached dams just in the Northeastern United States in recent years, said Jessica Louisos, a civil engineer with the Waterbury firm Milone & MacBroom and a co-author of a report on Vermont dams by the American Society of Civil Engineers (ASCE). In 2005, a dam in Fort Ann, N.Y., gave way, causing substantial property damage. In 1996, a New Hampshire motorist was drowned by flooding caused by a breached dam.

As far as engineers know, Vermont dams are safe. But they readily admit there is much that they do not know, and Louisos said “the lack of information poses a risk.” Nobody knows for sure how many dams are in the state. The ASCE report counted 1,219 in the “state inventory” 198 of which, or 16 percent, “are classified as high significant-hazard-potential.” (The big hydro dams are regulated by the Federal Energy Regulatory Commission or the state Public Service Board, and are not part of the state inventory).

That classification does not mean that they are in danger of failing. It means that if they did fail, the resulting flood would seriously endanger life or property. But 39 of those dams, Bushman said, have been “identified (as being) in poor condition, and need to be corrected before they get to that unsafe level. For most part they are not being ignored. They’re being looked at by engineers.”

In all, found the ASCE report, 126 dams, most of them considered “low-hazard,” are in poor condition. Neither Bushman nor Louisos doubt that there are some small dams that are not part of the state inventory. They suspect that there might be dams whose existence is unknown either to state officials or to the owners of the property where the dams were built years ago, perhaps in forests or fields not visited in decades. The ASCE report said “many small, privately owned dams are not listed in the state inventory.” Furthermore, Louisos said, dams behind which sit less than 500 cubic feet of impounded waters, “are not on the inspection list.”

Bushman said the high-hazard dams are inspected annually and the significant-hazard dams at least every five years. His goal is to inspect the low-hazard dams at least every ten years, but acknowledged that he and his one colleague – even with one part-time summer assistant – are behind schedule, and that some low-hazard dams have never been inspected.

To the dismay of dam safety experts, Gov. Peter Shumlin’s proposed Fiscal Year 2016 budget calls for a small decrease in spending on dam safety. A bill (H. 37) now under consideration by the House Fish and Wildlife Committee would not add funding, but it would require dam owners to register dams and pay an annual fee to fund the state dam inspection program.

Its sponsor, Committee Chair David Deen, a Putney Democrat, does not expect the measure to pass both houses this year. More than half of Vermont dams are privately owned, according to the ASCE report. Their owners are responsible for them, meaning they would be liable for any damages caused by their dam’s failure. These land-owners, says the report, “tend to have limited willingness to invest in maintenance and repairs.”

Dams, of course, do a lot of good. They create cheap and clean electricity, help irrigate crops, and create impoundments (lakes) where people love to swim, fish, boat, or simply enjoy the view.

But dams also do a lot of harm. As Clark Amadon put it, there is an “inherent disconnect” between dams and rivers. A dam invades the natural processes of a stream. Not only does it keep some fish from getting to their spawning beds, it alters –in most cases, degrades – the distribution of sediment, woody debris, and insect life that make a river…well, a river, as opposed to an artificial system created by human beings.

That helps explain the growing dam-removal sentiment around the country. It has already had some impact in Vermont, where only one dam has been erected in recent years while ten -- including the one on Cox Brook – have been torn down.

As more are likely to be in coming years. To begin with, it’s cheaper to remove a dam than to repair it. The ASCE report said removing all the dams in poor condition would cost $22 million, less than the $35 million it would cost to repair them.

The engineers and anglers (openly) and state natural resources officials (less openly) both favor getting rid of dams that no longer serve their original purpose, whether that be hydro power or irrigation. There is some opposition, both from landowners and from residents who simply want things to stay as they are, but for now, the momentum seems to be on the side of the dam removers.

Some of whom, like Trout Unlimited, are anglers, who may hope that they will catch more fish if the dams are taken away. But Amadon, an outreach counselor for the Vermont Student Assistance Corporation, said the fish themselves are not the focus. Habitat is. As much as possible, he said, a river should be restored to its natural state for the sake of restoring the river to its natural state. The fish, then, “will take care of themselves,” he said.

Besides, he said, in many cases a landowner can have a dam removed without paying for it. Removing the Cox Brook dam, he said, was financed by the U.S. Fish & Wildlife Service as part of its effort to protect and restore native brook trout fisheries throughout the Northeast. The Dog River, he pointed out, is one of only two in Vermont (the Battenkill is the other) managed as a wild trout fishery, with no stocking.

But even elsewhere, he said, the federal and state governments, with some help from volunteer organizations, would pay for most if not all dam removal. And a removed dam, unable to be breached, can do no harm.