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Fatal 1996 incident was 'wake-up call' for NH dam safety

By SHAWNE K. WICKHAM
New Hampshire Sunday News

February 25. 2017 9:42PM

Hazardous dams: Who owns them
More than 300 New Hampshire dams are designated as either "high hazard," meaning a failure would likely lead to loss of life, or as "significant hazard," meaning a failure would risk "major economic loss to structures or property."

Here's a look at their ownership:

HIGH HAZARD : 150
Federal: 13
Local Government: 42
Private: 38
State: 51
Utility: 6

SIGNIFICANT HAZARD: 157
Local Government: 66
Private: 54
State: 37

Ask Steve Doyon about a fatal dam collapse in Alton 21 years ago and he instantly recalls the victim's name: "Lynda Sinclair."

"I'll never forget it," he said. "There are some things in your professional career that you just can't forget, and that's one of the things."

Doyon is the administrator of the dam safety and inspection section at the state Department of Environmental Services. He's been a dam safety engineer for 30 years.

On March 13, 1996, a privately owned earthen dam on Meadow Pond failed, sending a 10-foot wall of water and giant chunks of ice rushing through an Alton neighborhood.

Lawrence and Lynda Sinclair lived below the dam and tried to flee. He drove his tractor-trailer; she took their pickup truck.

The surge of water damaged 17 homes and a wide section of Route 140, tumbling Lawrence Sinclair's big truck into a deep void. From the cab, he watched as his wife's vehicle was swept away.

Her body was found six days later in the Merrymeeting River. She was 48 years old.

A local pastor said the Sinclairs had planned to renew their vows at a 21st wedding anniversary party the day after the accident.

Doyon recalls getting a phone call from state police that night. By the time he got to the scene, the Meadow Pond reservoir had emptied, he recalled. "There was just a stream running through the bottom of the breach."

And downstream, he said, "You could see the bark ripped off all the trees up to 10 to 15 feet off the ground."

An investigation into the collapse found flaws in the dam's design and construction. It was never rebuilt.

Reached by phone recently, Lawrence Sinclair declined to talk about the tragedy.

Doyon says what happened back then was "a wake-up call" for New Hampshire.

Hazard levels

Most of the state's 2,600 dams - 78 percent - are privately owned. Twelve percent are owned by municipalities, 8 percent by the state, 1 percent by the federal government and less than 1 percent by public utilities, according to DES.

The "vast majority" of dams here are classified as "non-menace" dams, Doyon said.

But 150 dams are classified as "high hazard," meaning their failure would likely lead to a loss of human life, according to Doyon. Most of them are owned by the state, cities or towns; 38 are privately owned.

At some dams, a potential failure would trigger evacuations, according to Doyon. These include the Moore Reservoir Dam in Littleton and Comerford Dam in Monroe, both owned by TransCanada, and the state-owned Murphy Dam in Pittsburg.

The impact zone for the 193-foot-tall Moore Dam, he said, reaches all the way south to Hinsdale. "That's almost the entire length of the Connecticut River," Doyon said.

And failure of the Moore dam could cause other downstream dams to fail, he said.

There are also 157 "significant hazard" dams in New Hampshire; where a failure could lead to "major economic loss to structures or property" and damage to major roads, according to DES.

DES requires most owners of high- and significant-hazard dams to file Emergency Action Plans with the state, detailing the potential extent of downstream flooding, emergency actions to be taken upon indication of an impending dam failure or unsafe condition, and notification plans.

The Federal Energy Regulatory Commission oversees utility-owned dams; federal inspectors check those annually.

Doyon and his team of three engineers inspect the rest on a regular basis. High-hazard dams are inspected every two years, significant-hazard dams every four years and lower-hazard dams every six years.

Paying for repairs

Dam owners are notified of inspection results and given a time frame in which to complete any needed repairs.

The cost of repairs and upgrades falls entirely on the owners.

Keene will spend nearly $4 million over the next three years to upgrade three city-owned dams, according to City Engineer Don Lussier. Two of them, the Babbidge Reservoir and Woodward Pond dams, which provide the city's water supply, are actually in neighboring Roxbury.

Several years ago, the state passed new regulations for high-hazard dams, Lussier said. "You have to be able to demonstrate that the dam can safely pass two-and-a-half times the flow that would result from a 100-year flood event," he said.

The Babbidge dam will undergo upgrades this summer, Lussier said. The city's Goose Pond dam is scheduled for improvements next year, and the Woodward project is set for 2019.

Keene has been proactive in maintaining its dams, Lussier said. "I think what's really driving it is a keen awareness that our water supply depends on the viability of those dams."

The city is also committed to "climate resiliency," he said. "That's just part of the culture here in Keene."

Woodward is 105 years old; Babbidge was built in 1931 and "served admirably for a long time," he said. "But they have to be cared for and loved and maintained."

There are no matching state or federal funds for dam upkeep, Lussier noted. "That is 100 percent local money," he said. "That's kind of the challenge."

Dams are regional assets, providing water and recreational resources for many communities, Lussier said. "If I could wave my magic wand, I would love to see some participation from the state and federal government in the cost of meeting these new, higher design standards," he said.

Doyon said he thinks New Hampshire does "a pretty good job" of regulating dams. But the lack of funding is a challenge, he acknowledged.

Engineers have to consider the effects of climate change as they figure out what a dam should be able to withstand, he said. A dam rated as a non-menace dam when it was built in the 1970s could now be classified as a high-hazard structure.

And when it's a private owner, he said, "It's not an easy conversation to have."

Doyon said he hopes that fines collected for non-compliance could someday be used for low-interest loans to help other owners bring their dams into compliance.

Failure scenarios

The most likely dam failure, Doyon said, is a spillway that can't handle the amount of water coming. "And when that happens, water starts going places you didn't intend it to go."

That's what caused a spillway at a massive California dam to erode earlier this month, forcing nearly 200,000 residents downstream to evacuate.

Doyon's been watching the California situation closely. "I'm a dam nerd," he acknowledged.

In New England, the biggest concern is heavy rainful on top of a deep snowpack that melts too quickly, Doyon said. Engineers from DES and the Army Corps of Engineers have been taking snowpack measurements since January, tracking the amount of water it contains to calculate potential risk.

The worst-case scenario is the kind of flooding that hit New Hampshire in 2005 to 2007, Doyon said.

"I think those are the scariest types of events," he said. "You have so many people in the path of danger and you have so many more dams that potentially could be stressed beyond their limitations."

What happened in Alton 21 years ago was a deadly reminder of what water can do, Doyon said.

Too often, people attempt to flee floodwaters in a vehicle, he said. "It's just a big box of air on rubber tires," he said. "When the water gets beneath the wheels, cars float."

"Moving water is extremely powerful, and people don't give it enough credit," he said.

swickham@unionleader.com


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