Durham debates the fate of the Oyster River Dam and Mill Pond

It was the Oyster River’s promise of hydropower that first brought settlers to Durham some 350 years ago. Workers built mills along the river and set up a series of timber dams to harness water power, one of which created Mill Pond around 1740. The town took ownership of the Oyster River Dam in 1913, and many of its residents have cherished the pond’s recreational and viewing opportunities ever since.

Today, however, the dam no longer serves any industrial purpose. It has not been repaired since 1974 and is in dire need of costly renovations. And, according to officials from the N.H. Department of Environmental Services and N.H. Fish and Game, the structure is depleting the river’s ecological health.

Durham is in the midst of a debate over what to do about the Oyster River Dam. The debate boils down to three main options: The town could rehabilitate the historic dam, replace it with a new structure, or remove it altogether. The latter option is the cheapest, but it would mean the end of Mill Pond.

“The Mill Pond has historic, cultural and social value for the community. It has for many, many years,” said town administrator Todd Selig. “At this point in time, we are initiating a discussion with regard to the future of the dam. No decision has been made to date with regard to how the community should proceed.”

NHDES sent a letter of deficiency to Durham in 2002 demanding repairs to the Oyster River Dam. According to a report from Stephens Associates Consulting Engineers, an inspection of the dam revealed significant concrete cracking, spalling, erosion and exposed corroded rebar in several places. Floods in 2006 and 2007 also caused substantial damage to stone masonry walls and an embankment.

Stephens Associates estimated the cost of rehabilitating the dam at between $1.2 million and $1.7 million, while the cost of decommissioning the dam would be between $600,000 and $788,000. That’s a difference of up to $1.1 million. (The consulting firm did not evaluate the cost of replacing the dam, as the town does not appear to be seriously considering that option.) 

Furthermore, a number of state and federal agencies make grant monies available for decommissioning dams, potentially making the procedure much cheaper. Few grants, if any, would be available for repairing the dam, Selig said.

Nevertheless, a number of town residents are loath to see Mill Pond disappear. Among those people is Jerry Olson, who has lived on Mill Pond Road with his wife for 13 years. The pond offers a “wonderful opportunity to spend time in a canoe or kayak on a freshwater pond,” Olson said. “The pond is a unique feature of this part of Durham.”

Olson took pictures of the pond after it was temporarily drained so that inspectors could assess the dam. He and other abutters worry that eliminating the pond would leave behind a muddy and unsightly breeding ground for mosquitoes.

But Deborah Loiselle, who works in the dam bureau at NHDES, said areas surrounding rivers tend to heal quickly. While Mill Pond would initially leave behind a damp landmass, it would quickly transform into a free flowing river surrounded by plants and animals. “It’s very amazing how the seed banks will just come through and you’ll see a lot of the local vegetation,” she said.

There are about 5,000 dams in New Hampshire, Loiselle said, many of which are now inactive. Dams are almost always hurtful to the rivers they constrict, especially for fish that migrate between saltwater and freshwater. Although the Oyster River Dam has a fish ladder, it is one-way and only targets certain species, she said.

“Rivers don’t like dams. Rivers like to flow naturally,” Loiselle said, adding that free-flowing rivers provide higher water quality and keep sediment moving. “That is good for the overall ecological health of a river.”

Selig, Olson and Loiselle all agree that generating discussion about the dam issue should lead to an appropriate decision. Despite his concerns, Olson said the town is dealing with the situation fairly. And despite her environmental priorities, Loiselle appreciates that townspeople are attached to Mill Pond and the Oyster River Dam. 

“If it was purely an environmental issue, definitely, dam removal would be the way to go. However, there are a lot of issues,” she said.

The town’s Department of Public Works will hold a public meeting about the Oyster River Dam in Durham Town Hall at 15 Newmarket Road on Wednesday, March 4 at 7 p.m.