There are 4,000 dams in Connecticut. Learn more about them in this Q&A with DEEP. – Hartford Courant

Editor’s Note: This story is part of an occasional series about infrastructure in Connecticut.

Every dam in the state, about 4,000, must be registered with the state Department of Energy and Environmental Protection, and about 3,000 of them are DEEP-regulated, which means that owners should inspect and repair them periodically.

Here’s what you need to know about dams in the state:

Does DEEP even monitor small dams on private property?

Yes. DEEP does not regulate all dams in the state, but those that are so small that they fall outside DEEP’s oversight must still be registered. Graham Stevens, DEEP’s office manager for water protection and land reuse, said: “A lot of people think of this as ‘This is my Koi pond in the backyard.’ But there is a dam holding back the water. And if it were to fail, there really is no risk.

What are the grades and what do they mean?

The definitions, provided by DEEP:

Class C: A high-risk dam that, if it were to fail, would likely cause loss of life or great economic loss.

Class B: A dam with significant risk, indicating possible loss of life or significant economic loss.

Class BB: A moderate risk dam, the failure of which could damage normally unoccupied structures or paved roads, or cause moderate economic loss.

Class A: A low risk of damage, damage to farmland or local unpaved roads, minimal economic loss.

Class AA: A negligible risk of harm, not regulated by DEEP unless owned by the state. You still need to be registered.

“You need to have an inventory,” said Ivonne Hall, civil engineer supervising DEEP for dam safety. “We need to know about all the roadblocks that exist just so that if someone comes to us in the future and says, Hey, did you know about this roadblock? We know. We are aware of this.

Does a C rating mean a dam is unsafe?

No. According to Charles Lee, deputy director of the State Dam and Dam Safety Program for the Department of Energy and Environmental Protection, a C rating is considered a “high-risk dam, which means that if it were to fail, it would result in loss of life [in] the area of ​​the flood zone that would be flooded if this dam were to fail. … So he could be in great shape.

Who inspects dams in the state?

Since 2014, the responsibility rests with the owner of the dam, Stevens said. “Homeowners are required to hire a professional engineer to perform this inspection,” he said. “And, these are obviously licensed people who are putting their license on the line with this inspection. And we have great confidence in this group of professionals who carry out these inspections. So it’s a very good safety measure for the public to have that in place. »

How is this applied?

Dam owners must file an inspection report with DEEP, which focuses on “reviewing, with the greatest timeliness, reports for the dams that pose the highest risk,” Stevens said. He said the program caused dam owners to apply for a dam safety permit to make modifications to dams that failed inspection or to remove the dam altogether.

A 2021 state law adds roadblocks to what a real estate seller must disclose to a buyer. “Properties are changing hands,” Stevens said. “So we are constantly trying to get the notices to the owner. This may be news to them because they may have purchased the property and did not know there was a dam. They may have been badly advised or did not take advice during the acquisition. And now it’s something they have to sort out.

How often should dams be inspected?

Dams rated C must be inspected every two years, B every five years, BB every seven years and A every 10 years.

Who owns C-rated dams?

Most of them are owned by water companies and are located in reservoirs, Stevens said. “And the good news is that water companies are professional companies that have professional engineering staff who maintain their infrastructure very well. And often water companies do high-frequency inspections and come in to really make their dams more resilient.

“I think the water companies are doing a great job at all levels, trying to ensure that these dams that protect our drinking water, potentially also put people at risk, are as resilient as possible to ensure that they are properly fortified and only technically able to retain the water that is usually there as well as the water that may sometimes be there after a larger storm.

What is an impoundment?

It is the water behind the dam that is prevented from flowing downstream.

How many dangerous dams are there in Connecticut?

This is not data shared by DEEP on its website “because this information is constantly changing,” Hall said. “What we put on the website is really a snapshot of the dams that have received reviews. We are required by law to January of each year, before the 15th, we must send notices to all dams that are due for inspection. … But we don’t put the condition rating on the website, because it would just be permanently outdated.

However, Lee said, “Our files are publicly available and generally what we do is deposit and file them. So when people have questions or want to look at a particular dam, they can come and see the file.”

In May, the Associated Press published a survey of dams in 42 states, finding 2,200 high-risk dams rated in poor or unsatisfactory condition, including 20 in Connecticut, up from 1,680 three years earlier. He also found that the US government keeps the status of many dams secret.

Why would someone remove a dam?

Many dams are removed because they were used in factories during the industrial age, are no longer needed, and prevent fish from swimming upstream to spawn.

“There were a lot of textile mills and other dams that are no longer in use, so we’re getting permit applications for removal projects,” Hall said.

How many dams are there in the United States?

Nearly 92,000, according to the National Inventory of Dams, which is maintained by the Army Corps of Engineers. The average age is 61 years old.

Is there money available to repair the dams?

Five things you need to know

Five things you need to know


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Yes. The infrastructure bill signed by President Joe Biden includes millions of dollars for repairing, renovating and removing dams.

What are the most recent major dam failures in Connecticut?

The last major failure was in 1982 at the Bushy Hill Pond dam in Deep River, which caused $50 million in damage but no fatalities. In 1963, the Spaulding Pond Dam in Norwich collapsed, killing six people and causing $6 million in damage.

How many Class C dams does the metropolitan district have?

New. Recent major repair projects include:

Phelps Brook Dam and East Dyke Rehabilitation, 2018, $1.46 million; Replacement of locks at Nepaug Dam and two-dam Phelps Brook Dam, 2017, $955,000; and West Hartford No. 2 Reservoir Rehabilitation, 2015, $4.275 million.

Ed Stannard can be reached at [email protected] or 860-993-8190.

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