Town leaders in Alton monitoring Wentworth Pond drawdown, especially ahead of weekend Nor'easter

ALTON — The state made good on its promise to lower the water level of Wentworth Pond on Sept. 22, draining 12 feet, scheduled to remain that way for the following two weeks.

According to a report provided by Town Administrator Ryan Heath on Sept. 22, a construction crew with the New Hampshire Department of Environmental Services set up for sediment removal in front of the outlet.

Two temporary “sediment retaining features” were installed on the downstream section of the dam, with one using filter fabric draped over straw bales for discharge into a vacuum truck. Another is a bag that collects sediment discharged from pumps set up at the site.

“The have repositioned the downstream silt/sediment curtain to better contain sediment escaping during the drawdown,” the report stated. “Additionally, they have installed a sediment curtain upstream of the low-level outlet to contain disturbed sediment during sediment removal and to assist in retaining sediment upstream of the low-level outlet during drawdown.”

Heath said a vacuum truck brought onsite by the state was ineffective in removing sediment.

Heath’s report stated the alternative was to keep stop logs in place downstream. while opening the low-level outlet valve so sediment could flow into a chamber between the two. Water samples were collected downstream to check for contamination from the discharge.

Heath also provided a report from Corey Clark, NH DES Dam Bureau chief engineer, saying a gate on one side of the dam was able to be fully opened. He believed most of the material upstream was made up of sand, gravel, and other organic matter.

“Fortunately, none of the material caused gate operational issues and we believe at this point the gate is fully operational and could be used as necessary,” Clark stated in the report on Sept. 22.

All but the bottom stop log had been removed from the downstream side. He noted that when the state workers left the site that day, the water level was 74 inches below the concrete. There was a small amount flowing over the spillway, as well. He noted the gate was left only four inches open, resulting in the water level dropping two inches that day.

Clark ensured NH Fish and Game, which owns the dam, was to check on the water level and make sure the pond wasn’t lowering too fast. He said DES and Fish and Game would continue monitoring, and adjust the opening of the gate if necessary.

The state agencies planned to monitor the water line upstream of Route 140, as well, and checked various locations throughout the week, while the water level decreased. With rain in the forecast, Clark said there may be additional checks.

“They are doing the full impoundment drawdown to do testing and check the base of the dam,” Heath told the selectboard on Sept. 22, during their bimonthly meeting.

Heath reiterated from previous conversations he was working with legal counsel and had made positive headway in locating experts who could help the town’s cause in potential ownership of the Alton Power Dam at Wentworth Pond. The dam is currently owned by NH Fish and Game, and maintained by NH DES.

“We’re still in contact with legal, and pursuing legal avenues,” Heath said.

He said the first group of experts he reached out to declined to work on the project, because of a conflict of interest. This didn’t surprise Heath, as many big firms likely deal with NH DES regularly. The good news was Henniker-based firm Gomez and Sullivan Engineers will likely be able to help the town in a one-stop-shop scenario.

“I thought we were going to have to find several experts to cover most of these, but this firm has the capabilities and the personnel and resources that specialize in every area I just covered,” Heath told the board.

The firm solely works on dam projects, and Heath said he is putting together the scope and proposal, for the board to provide an outside review of the sampling done by NH DES and Fish and Game. He said the firm does this “every day,” and can analyze records and put together an “independent, non-biased opinion.”

Heath said the firm specializes in engineering and hydropower engineering; dam safety and dam safety inspections; hydropower licensing; environmental and hydrology studies; hydrology and hydraulics; fisheries and fish passage; stream and habitation restoration; and GIS data.

He said the important aspect will be analyzing the elevation of the spillway, as this has played into the categorization as a high-hazard dam.

Heath was “thrilled” to meet them and is confident they will be a good resource. He has been in contact with the firm since Sept. 16, and expects a report next week to share with the board.

Chair Paul LaRochelle stressed the urgency.

“Time is of the essence.”

Controversy

Residents have been outspoken at selectboard meetings about their disapproval of the drawdown, citing concerns about the environment as well the value of their property. While a drawdown has been discussed since earlier this year, it became a major issue at the selectboard meeting Aug. 11.

Clark addressed the board that night to tell them of a 12-foot drawdown. Members of the selectboard and town staff were vocal about their concerns and frustration. Many said they felt it was being rushed because of upcoming state budget restrictions, and thought the repercussions could outweigh the positives through studies.

Town leaders and the public alike have said they're worried the state will ultimately remove the dam. However, at the Governor and Council meeting on Sept. 16, Executive Councilor Joe Kenney asked NH DES Commissioner Robert Scott if there were plans to remove the dam in the spring. Scott said there is no plan to do so, and the state doesn’t have the resources to do so.

Kenney, who attended the Aug. 11 selectboard meeting and heard the concerns, said he has been hearing from constituents about the dam, and will be an advocate. He was given a tour of the area by Don White, who shared concerns about losing the dam.

White was at the dam the week before the drawdown. He told The Laconia Daily Sun the marsh area above the dam is beautiful, and full of a variety of wildlife, and he fears it would ruin their habitats and ecosystems.

The drawdown originally came before the selectboard in the spring, proposed by NH DES to lower Wentworth Pond, behind the dam, by 2.5 feet. This was for data collection, passive restoration and to provide for additional storm discharge capacity. It was postponed due to ice conditions, and rescheduled for Sept. 2.

Following the outcry at the Aug. 11 meeting, the state altered its plan to drawdown about 2 feet to start. The remainder was to take place Sept. 22.

Town leaders were angered by NH DES staff dropping off a stack of paperwork at Town Hall Sept. 1. Heath called it “unbelievable.”

Heath was frustrated there had been little support from legislators. Reps. Barbara Comtois (R-Barnstead) and Peter Varney (R-Alton) did not respond to requests for comment.

Sen. Jim Gray (R-Rochester) said in an interview, Sept. 18, while he understands the town’s opposition, if the dam were to ever fail, it could be catastrophic, or even deadly. Gray said the drawdown will allow state staff to inspect the dam thoroughly.

Rep. Paul Terry (R-Alton) said, on Sept. 22, it's true concerns of affected property owners and members of the Alton and New Durham communities “have seemingly fallen on deaf ears,” but the wheels are turning.

“In my opinion, DES has handled this matter with an almost cavalier attitude,” Terry said.

He said he will be “lending support to the effort,” and Rep. Susan DeRoy (R-New Durham) has drafted legislation to address what they both believe is “agency unreasonableness and overreach."

He deferred other comments to her. A request for comment left with DeRoy on Wednesday was not immediately returned.

The water level will remain reduced for about two weeks, ending Oct. 6. Clark said it will gradually refill to the “operating level prior to the onset of winter conditions.”