Ridgefield’s Fox Hill flood control dam repairs could prove costly
The flood control dam near the Fox Hill condominiums and issues related to its uncertain future — concerns, costs, questions — remain on the town’s to-do list entering the new year.
“The concern is the entrance of Fox Hill, it could breach that area — flows from a 100-year flood could cause enough to a breach to wash a car away on Route 35,” First Selectman Rudy Marconi told the finance board.
“There’s nothing wrong with the dam today,” Marconi added
A public information meeting on the earthen, grass-covered dam — which builds up a substantial pool of water behind it in times of heavy rainfall, but allows normal flows from Ridgefield Brook to pass through — is planned for Jan. 29 at 6:30 p.m. in the Ridgefield Recreation Center. The “snow date” would be the next night, Jan. 30, in the event of a meeting cancellation.
Marconi gave a brief update on the dam at the end of the finance board’s Dec. 18 meeting, after discussing it with involved state officials earlier that day.
A reexamination of the dam was prompted by a study done by a consulting firm for the Natural Resource Conservation Service (NRCS), a federal agency that oversees many dam projects around the country.
The alternatives being studied range from repairing the dam to removing it.
“The cost of improving the dam is $6 million. The cost of removal is $3 million,” Marconi told a selectmen’s meeting early in the fall, when the dam issue first resurface locally.
Another option would be not doing anything.
Both the federal NRCS and the state Department of Energy and Environmental Protection (DEEP) have a role in the reexamination of the dam and the need for it.
Their analysis suggests the flow from a dam breach after a 100-year flood could be absorbed by the wetlands downstream of the dam, along the Ridgefield Brook as it becomes the Norwalk River, Marconi told the finance board.
“They did a complete study, all downstream to Ace Tire,” Marconi said. “In the event of a 100-year flood, the current wetlands would handle the flooding.”
Town officials, he said, were still considering hiring a hydrologist to provide an independent perspective on the numbers.
“We had some questions on the calculations and hydrology,” Marconi said.
A dam breach isn’t a constant looming threat, as it would be with a dam that always had water behind it. Most of the time there isn’t that much water behind the dam — flood control dams let normal stream flow pass through, and water only builds up behind them to create a sizable flood pool in times of heavy long-lasting rains.
But the dam is earthen, so there is concern that in a really large storm it could be breached, especially if waters “overtopped” the dam.
State and federal officials keep an eye on the dam, so a breach isn’t a major threat, NRCS hydrologist Ben Smith told The Press in an interview in the fall.
“No, it’s not really something to be worried about. There’s an emergency action plan in place,” Smith said. “...If there’s a major storm they go out and look at the dam ... Will it overtop? Is there going to be any sort of problem? And then (they) work with local emergency management people to get anyone out of harm’s way...
“It’s not like something sitting unattended,” Smith said. “They send people out to look at this in major rain events.”
Still, the conditions that could lead to a dam breach might occur — and that could potentially lead to serious problems.
The consultants studying the dam for federal and state agencies recommended further research on it, with a goal they described as “reducing the potential for flood damages and loss of life from a catastrophic breach.”
Citizens with questions about the dam that they’d like answered at the Jan. 29 meeting may send them in ahead of time, and the advance notice will allow for more in-depth of answers.
“Send your questions in advance,” Marconi advised.
Marconi’s office in town will accept the questions by email, phone or U.S. Postal Service mail, and the town will forward them to the scientist studying the dam.
The email is firstname.lastname@example.org. The phone number is 203-431-2774. And mailing address is First Selectman, Ridgefield Town Hall, 400 Main Street, Ridgefield CT 06877.
The discussion at the Dec. 18 meeting, Marconi said, suggested that the federal government sees — or would like to see — full responsibility for the dam residing with the State of Connecticut.
Paraphrasing what he saw as the federal attitude toward the state, Marconi said: “You own the dam.”