Dam Removal

For thousands of years, the Ipswich River ran free from source to sea, and bountiful runs of migratory fish returned from the Atlantic every year to spawn. Then dams were built to power industry, stopping fish migrations and greatly changing the nature of the river. Most of these dams no longer serve their intended purpose, but they continue to block the movement of fish and drown riffles and natural rapids. If restored, these natural river features would provide important habitats for fish and other creatures, add oxygen to the river’s waters, and offer us beautiful views now buried under several feet of water. Dam owners across Massachusetts must maintain and repair their dams and are liable for any safety hazards—many are opting to remove their dams to remove liability and maintenance costs. Owners are helped by generous state and federal programs that fund removal of dams that impact native ecosystems. For more on dam removal please check out this informative video from American Rivers.

Removing dams on the Ipswich River will be a multi-year process. First the dam, pond and surrounding site must be closely studied to see what effects its removal would have on safety, infrastructure, and the health of the river.  Initial studies often ask: Are there are any pollutants in the sediments behind the dam?  Will removing the dam reduce or exacerbate flooding? And, will removing the dam threaten or help nearby buildings or bridges? Once this study is complete and if the owner decides that they want to remove the dam, they develop an engineering plan to outline removal and site restoration. Only once this plan is approved by local, state and federal agencies, can the dam removal actually begin.

IRWA is collaborating with dam owners, state and federal agencies, and funders to study the feasibility of removing three dams: The Ipswich Mills Dam in downtown Ipswich, the South Middleton Dam in Middleton and Curtis Pond dam on Boston Brook in Middleton, a tributary to the Ipswich River. Taken together, these three studies represent some of the most significant advances to date towards better understanding the problems dams pose to the Ipswich River and to identifying potential solutions.

The South Middleton Dam at high flow

South Middleton Dam:

The South Middleton Dam is a stone and wood dam owned by Bostik, Inc. It is the third dam on the mainstem of the Ipswich River from the river mouth and the first without a fish passage structure of any kind. There are several tributary streams upstream of the South Middleton Dam that would be opened to fish migration following dam removal. The total number of river miles that would be opened up as result of dam removal is estimated to be over 56 miles.

Nick Nelson of Inter-Fluve, Inc. maps the sediments above the South Middleton Dam

Bostik, Inc. is concerned about the long-term maintenance, liability and environmental costs associated with the dam and would like to remove the dam if it is economically and logistically feasible. IRWA, began collaborating with Bostik, Inc. in 2008 and in 2009, received a $21,000 grant from the Gulf of Maine Council/NOAA Habitat Restoration Partnership and $10,000 grant from the Massachusetts Division of Ecological Restoration to assess the level of sediment contamination behind the dam and the infrastructure needs of the adjacent factory site. Bostik, Inc. also contributed $5,000 to the study. The study was completed in June 2010. Download a short presentation of results or the full report.

The Ipswich Mills Dam

Ipswich Mills Dam:

The Ipswich Mills Dam is owned by the Town of Ipswich and is located on the Ipswich River in downtown Ipswich. The dam is the first from the sea, built on a natural rock outcrop at the head of tide 3.7 miles from the river mouth. The interface between salt and fresh water is an extremely rare and productive ecosystem and the presence of the dam at the head of tide is especially detrimental. The dam is constructed of granite blocks and has an overall length of 200 ft, with a 120 ft long overflow spillway. It was constructed to power adjacent mills and currently has no functional use. A Denil fishpass was installed in 1995, but does not allow all fish species to pass.

Artist's rendering of the historic "Upper Falls" below the current Ipswich Mills Dam

The Town of Ipswich recognizes that the long-term maintenance, liability and environmental costs associated with the dam. On March 29, 2010 the Ipswich Board of Selectmen voted unanimously to begin exploring the environmental, technical, logistical and economic factors surrounding the removal of the Ipswich Mills Dam.  The purpose of the Ipswich Mills Dam Study is to examine three priority factors influencing a decision to remove the dam: a) the effect of dam removal on the foundation of an old mill building adjacent to the dam; b) the effect of the dam and its removal on upstream and downstream flood levels; and c) contaminant levels (if any) in the sediment behind the dam. 

Curtis Pond

The Curtis Pond Dam:

The Curtis Pond Dam is an obsolete dam owned by the Town of Danvers on Boston Brook in Middleton. The Town of Danvers is planning to remove the dam, and in 2009 the initiated a study of the site’s hydrology, topography and environmental health as the first step towards removal. The study was funded jointly by the Town of Danvers and Gulf of Maine Council/NOAA Habitat Restoration Partnership. IRWA assisted with water quality monitoring and public outreach. The study was completed in June 2010. Download the presentation of results here. Please visit this page in July 2010 to download the full report.