By PAULA TRACY, InDepthNH.org
PITTSBURG – Built almost 90 years ago and named for the 64th governor, Francis P. Murphy, Gov. Kelly Ayotte, the 83rd governor made an early morning visit to the Murphy Dam on Lake Francis here, Wednesday marveled at the craftsmanship of the gate, learned of its important use controlling the Connecticut River Valley below and heard state plans to upgrade it for the next 90 years.
Anglers who were packing up their rods and reels from their casting efforts below the 2,200 foot long dam were approached by the governor as ATVs rolled by and kicked up the dust. She was dressed unassumingly in jeans, a T-shirt, vest and Hoka running shoes and sunglasses.
They welcomed her greeting and she asked if they had had any luck.
Alas, no trophies caught for them on this day, they told her though she later heard a 27-pound lake trout was caught recently in that area below the 117-foot dam.
As they spoke she could hear the hiss of the release of 300-cubic feet of water per second below the dam and watched as the release began churning in its flow down through Pittsburg, on to the rest of New England ultimately to Long Island Sound from here forming the 410-mile Connecticut River.
In some mechanical and practical respects, this gate controls the flow of the Connecticut River.
Executive Councilors Joe Kenney, R-Wakefield, Karen Liot Hill, D-Lebanon, John Stephen, R-Manchester and David Wheeler, R-Milford soon exited a separate van and met with Ayotte and Department of Environmental Services Commissioner Bob Scott and his staff to learn about the history and potential future of this important safety feature in the state’s infrastructure.
The council traveled by van and stopped at the top of the spillway and drove the half mile along the knife-edge high top of the dam overlooking the five miles of pristine water. Once a river surrounded by farms, the state bought the property and relocated Route 3 to build the impoundment, which includes at its center the brick, Broome Gate Tower where the exit is controlled by gates 100 feet below.
The governor and councilors walked a gangway into the tower high over the lake and looked at the iron and toothed wheels that have been in use all these years.
They learned that the near century-old equipment has withstood the test of time and water well and learned that it protects an inundation water zone that goes as far south as Dalton near Littleton.
The last time a map updating that zone was drafted was more than 20 years ago and with climate change and serious storms affecting the area, including two on the same date in July in two years, its releases impact water levels throughout the region.
Water inundation zones and concern for what recently happened this month in Texas has a lot more attention being focused on flood control.
Corey Clark, chief engineer for the DES Dam Bureau, explained to the group that Murphy is the state’s largest dam that the state owns and the largest built by the state.
The state has over 4,000 dams, many of which are owned and controlled by the state. Some are used for hydro power while others are used for recreation and control of water. Before there were dams in the area, flooding on a consistent basis occurred throughout the state and not only damaged properties nearby but shut down the mills at times.
It was an Army Corps of Engineer project which began in about 1938 and was completed in about 1940 with the approval of a quasi-state board that floated bonds to get the Murphy Dam and Lake Francis built. The state now owns all around the lake up to the height of the dam.
Its primary inflow comes from the chain of four lakes above it and at the other end, known as the Connecticut Lakes and Lake Francis is considered the man-made sister to the upper natural lakes.
It has a surface area of 1,934 acres, an average depth of 40 feet with its deepest spot, 110 feet at the foot of the dam.
The temperature of water coming out is from the bottom of the lake and it is quite chilly. It is in the low- 50-degree range right now at its bottom where the water is released.
The spillway, which can handle overflowing water from the dam in storm events, has a discharge capacity of 74,000 cubic feet per second.
With a surface elevation of 1,379 feet in Pittsburg, water released from the dam flows slowly downhill to sea level some 410 miles below in Long Island Sound.
As he spoke outside and below the dam wall, Clark said, “all the water comes in from that building at the top, the one that looks like a lighthouse and there is 13-foot diameter pipe that runs all the way down and splits into two boughs through here.”
Alan Williams, who works for the dam bureau and is the resident operator of the site, was alongside Clark.
He works closely with Great River Hydro because they own First Connecticut and Second Connecticut.
Clark said they work with the company to pass water down through the dam to their downstream facilities, for which they pay a water user fee.
Above, Rene Pelletier, Alan Williams and Councilor Joe Kenney are pictured in front of the Broome Gate Tower on the Murphy Dam. PAULA TRACY photo
The group also works with anglers and guides to keep them apprised of releases and temperature changes which can impact the fishery.
They described it as a balancing act at times managing water levels for summer recreation but not so much release as to flood downstream.
Williams told the governor and councilors that when needed they can fish with hooks to lift the gates in the gatehouse.
“Two of us with a rope and we actually use pole hooks…and we go down and fish them, hook them into a ring and pull them up,” Williams said.
Clark said there have been upgrades over the years, the most recent was some post COVID-19 American Rescue Project Act funds used to help make improvements on the dam and other upgrades to electrical lines, and a number of studies including looking at redoing the spillway infrastructure “and the most pressing thing we have here is the two valves down here obviously 1938 vintage and trying to get those replaced.”
He said his goal is later this year to get a project off to bid using some of the water user funds, some capital funds and get those valves replaced.
Those contracts will come to the governor and Executive Council to approve.
“Moving forward on that we are going to continue to be studying other parts of the dam and really probably a much larger retrofit on the spillway portion,” he said.
The state controls the lake and leases out a few “camps” along its shores but those have no docks. The only structures are those for the dam use and the state’s use and at the Lake Francis State Park.
Known nationally as an excellent cold water fishery, Lake Francis has rainbow trout, brown trout, landlocked salmon, lake trout, and chain pickerel and is used in winter for ice fishing.
Francis Parnell Murphy, a Republican governor who became a Democrat in 1942, has both the lake and the dam named for him.
Born in Winchester he lived for many years in Nashua, like the current governor, and died there in 1958 at age 81.
Murphy was also responsible for one of the first ski area aerial tramways in the United States when the Cannon Mountain aerial tramway was built in Franconia Notch and that second version of the tramway is due to be retired this fall and replaced with a third in the coming years.
He was elected to the New Hampshire House of Representatives in 1931 and to Governor John G. Winant’s Executive Council in 1933.
In 1940 before retiring as governor, Murphy entered the broadcasting business, founding the Radio Voice of New Hampshire, Inc. and opened WMUR and created WMUR-TV in 1954. The station uses as call letters the first three letters of his last name, MUR.
Above, Gov. Kelly Ayotte speaks with Executive Councilors Joe Kenney, Karen Liot Hill and John Stephen at the Murphy Dam Wednesday. Paula Tracy photo
Ayotte listened as Clark talked about the history and environmental considerations and timing of any changes at the dam which might impact the important trout fishery and its stretch just below the dam and flowing behind the downtown area of Pittsburg toward the south.
“Because the water coming out 85 feet below the lake surface is very cold water coming out,” he said.
In retrofitting those valves it is important to maintain the trout fishery and not allow the temperatures to get too high as it comes out of the spillway, he noted.
So timing is key for determining the best construction window.
Working on temperature data in advance of such construction are devices in buoys on the lake and near the spillway that take real time temperature data which will be used to determine the best time to protect the fish, Clark said.
He said water release can be ramped up more than 10 times the current flow in cubic feet per second.
On Wednesday morning they were discharging 300 cfs.
“Just for an order of magnitude, the storm event that we have to pass is in the order of 3,600 cubic feet per second…So we are talking 100 times more discharge.”
He said some ARPA money is being used to update the inundation zone map.
“If this was to fail you would actually see devastation all the way down the Connecticut River Valley all the way to Dalton,” Clark said. “The reason I bring that up is there was…a little concern from local communities downstream not just New Hampshire but Vermont about the status of the emergency action plan. So I have been in communication with them. We are updating that with new models, new mapping so that way, all those downstream communities will…be updated.”
After Clark spoke, the governor said that this is important work so that “our emergency plans are prepared for that.”
Rene Pelletier, who is head of the Water Division of DES, said the current inundation plan for the Murphy Dam is likely over 20 years old and an update will help prepare everyone.
“Structurally, we believe it is OK,” Pelletier said. “Our first point of interest is to do something with the discharge pipes.”
Adam Crepeau, assistant DES commissioner, noted that when the Murphy Dam is referred to as a “high hazard dam it means it is high hazard if it failed” noting that is different than it being considered in disrepair, which he said it is not.
Clark said there is in-house capacity to do some of the structural work, but it would be more efficient if the larger projects go out to bid.
Cost estimate? Executive Councilor Kenney asked.
“I mean just for those two new valves that will be a $4 million project,” he said. Standing near the spillway he said the other work might be on the order of “tens of millions of dollars to renovate all of this.”
He said that would be put into the construction cost category of a new aerial tramway at Cannon.
Councilor Liot Hill asked what the life expectancy could be out of a renovation and was told it would likely be for another 100 years.
Ayotte said there are not enough resources to fix all the dams the state has but there is prioritization.
“It’s so critical to the community…this is a big deal if a dam breaks. It would have a massive impact on the community, the area, the ecology and wildlife,” she said.
The entourage then got back into their vehicles and moved along the one lane dirt strip of road on top of the dam to the Broome Gate Tower in its center.
Electrical power in Pittsburg did not come until the 1940s.
“One of our long-term goals is to bring power up here because we have a gas engine that we have to use when we have to lower the Broome gate which is sitting in the basement right there, basically a 13 foot wide by 13 foot wide panel that comes down to shut of the flows” to the Connecticut river “so we can do work or inspections” about 100 feet below.
The original designer of the gate was named “Broome,” Clark explained.
“I do have to give him credit, even back in the 1930s because the way he designed this gate is it can actually be used in emergency conditions, if we had to do an emergency shut down. But basically the gate gets lowered all the way down that 90 feet, shuts everything off and then comes back up. And everything has worked flawlessly for the past 90 years but is certainly time to upgrade things. While this mechanism will likely stay in place one of our goals is to bring electricity in here.” They use a stand-by generator system now.
Ayotte said, “I think it also shows the craftsmanship of 90 years ago.”