'State of disrepair': Durham makes call to remove Mill Pond dam on Oyster River

DURHAM — The future of the Mill Pond dam on the Oyster River has been debated for more than a decade, and now the fate of the dam has finally been sealed. 

The dam, which is roughly 140 feet long, forms the 9.5-acre Mill Pond, which has been used recreationally for fishing, boating and bird watching over the years. While many have advocated for either tearing the dam down or stabilizing it, the Town Council has decided to remove the dam in a 7-2 vote with Councilors Wayne Burton and Dinny Watters voting against the removal.

"Following much discussion and extraordinarily thoughtful statements by members of the Durham Town Council, the board closed an important chapter in Durham’s history ... to move forward with dam removal of the historic, head of tide Mill Pond Dam on the Oyster River," Town Administrator Todd Selig said in an email. 

Despite its historic status, the state’s Dam Bureau has identified several safety deficiencies associated with what is officially known as the Oyster River Dam, including concerns with its overall structural integrity and stability, according to a study prepared for the town by engineers VHB of Bedford. That study found that stabilization was more costly, wouldn't comply with the Dam Bureau’s safety regulations and didn't resolve all of the concerns regarding the water quality of Mill Pond.

Comparing the costs and facing the future

Council Chair Kitty Marple said the dam has been in a state of disrepair for nearly a decade. Marple said some argued the $1.5 million price to shore up the dam and leaving the pond would be comparable to the $1.9 million to remove it. Marple said the removal cost figure doesn't include the grants the town expects it can get to bring the price tag down. 

"Unfortunately the dam has slowly degraded and the concrete has been wearing away," Marple said. "The thing that sort of spurred us to get to where we are today was the condition of the Mill Pond. With the water quality, it is becoming more and more in dire straits."

The dam separated the fresh and saltwater portions of the Oyster River, which is a tributary of the Piscataqua River and part of the Great Bay Estuary in coastal New Hampshire. Marple explained that studies showed the Mill Pond is low in oxygen, which makes it an unhealthy environment for fish and underwater ecosystems. The dam also doesn't allow normal fish runs, which is a pathway along streams and rivers from the ocean to freshwater lakes and ponds that fish travel in order to reproduce. 

"The water will be free-flowing and the dissolved oxygen will increase because it is moving. It's just a healthier ecosystem in the long run," Marple said.

Marple said another study was completed to address questions from residents and abutters, and the results supported dam removal. The current concrete dam was built as a gift to the town from Edith Congreve Onderdonk. It was constructed in 1913 to replace the last of a series of timber dams which had been in place since the 1600s. It was originally built to to maintain the beauty of the Mill Pond and to supply water power to the adjacent Jenkins Mill. The dam currently does not serve as a power supplier.

"The water has been dammed for 400 years, and this dam has been in place for more than 100 years. It doesn't serve a real purpose like it once did," Marple said.