Conservation Spotlight: Beatty’s Mill Dam Removal is Complete

The removal of Beatty’s Mill Dam stands as a pivotal moment in the conservation efforts along the Musconetcong River. This critical initiative, spearheaded by the Musconetcong Watershed Association (MWA), Washington Township, and the Town of Hackettstown in collaboration with Princeton Hydro and RiverLogic Solutions, marks a significant stride towards rejuvenating the river’s natural ecosystem and addressing long-standing concerns regarding flood mitigation and habitat preservation.

History of the Beatty’s Mill Dam

Beatty’s Mill Dam straddles the border between Warren and Morris Counties in Hackettstown and Washington Township, New Jersey.  It is a 6-foot-high stone masonry, concrete, and earth embankment dam that was built in the 18th century and has been non-functional for decades.

Beatty’s Mill Dam is a low-head dam, which means it was not built to protect communities from flooding and can make flooding worse in some cases. Hackettstown and Washington Township are also more susceptible to flooding and erosion due to the high percentage of impervious surfaces, like roads and parking lots, which cause higher flows of stormwater runoff.

A dam safety report from 1981 shows that the dam had been breached on the eastern end. The breach caused a hairpin turn where the river is diverted sharply to the east then back to the west before flowing under the East Avenue bridge. Over time, this created erosive conditions at the upstream side of the bridge and roadbed, threatening the integrity of the infrastructure. Additionally, extensive alteration of the floodplain occurred upstream of the dam, including an elevated earthen berm along the left bank, and general land disturbance in both upland and wetlands.

The removal of the dam not only addresses the structural concerns but also holds the promise of extensive environmental improvements. By eradicating barriers to the Musconetcong River’s natural flow, restoring the floodplain, and implementing strategies to curb stormwater runoff, this initiative aims to mitigate flooding, promote water quality, and foster a thriving habitat for aquatic organisms including indigenous species like the Eastern Brook Trout and American Eel.

Removing the Dam

With funding from the Highlands Council, Princeton Hydro was contracted in 2019 by Washington Township to complete a water quality assessment, hydrologic and hydraulic analysis, and functional value stream assessment of reaches of the Musconetcong River that encompassed the Beatty’s Mill site (and the downstream Newburgh Dam site). Following the New Jersey Highlands Water Protection and Planning Council guidance, Princeton Hydro assessed and rated the river reaches on five functional values: channel integrity, habitat, water quality, temperature moderation, and public use. The Beatty’s Mill Dam, floodplain encroachment, narrow riparian buffers, and non-native riparian vegetation were the primary sources of impact to the functional values.

Subsequently, Princeton Hydro was contracted by MWA to complete a site investigation, wetland delineation, topographic survey, and preliminary (60%) engineering design for dam removal. Preliminary plans were reviewed by Washington Township and the Town of Hackettstown. In 2023, Princeton Hydro completed the final engineering design, hydrologic and hydraulic modeling, and permitting for the removal of Beatty’s Mill Dam and restoration of the floodplain and provided engineering oversight during construction.

The removal of Beatty’s Mill Dam was officially completed the week of November 13, 2023!

Princeton Hydro assisted in the removal and restoration, providing engineering plans and project management support. With the dam removed, 2.5 acres of flood plain have been restored; 0.15 mile of stream bank have been stabilized; 0.15 mile of stream bed has been rehabilitated; and total suspended solids in the water have been reduced by 20%.

Michael Allers, Princeton Hydro Restoration Ecologist and licensed FAA-Certified Commercial Drone Pilot, captured these aerial images of the completed project site:

It is projected that there will be significant improvement to the five aforementioned functional values, increased fish passage, enhanced hydraulic conditions at the East Avenue bridge as well as improvements to the river’s pH, temperature, and dissolved oxygen levels.

Removing the dam also supports conformance with the Highlands Regional Master Plan, which is intended to protect, preserve, and enhance precious water resources within the Highlands Region. The project work also includes the restoration of the damaged floodplain, stream banks, and stream bed by planting trees, building up the banks with rocks, and allowing the river to return to its natural flowing channel.

Looking Ahead

This project’s significance extends beyond the immediate environmental impact. Funding from sources like the National Fish and Wildlife Foundation under the Delaware Watershed Conservation Fund and New Jersey’s Highlands Council, along with corporate contributions, underscores its potential to serve as a model for similar restoration projects across the Delaware River Watershed. Such initiatives not only enhance aquatic habitats but also bolster community resilience against flooding and elevate public awareness regarding watershed conservation.

The vision for this restoration effort reflects a collective commitment to revitalize river ecosystems, not just for the immediate region but as part of a broader strategy for conservation. The Beatty’s Mill Dam marks the MWA’s sixth dam removed on the Musconetcong River since 2008, but it is far from the last. This project aims to set a precedent for sustainable river management and ecosystem preservation.

The removal of Beatty’s Mill Dam represents a milestone in the ongoing efforts to restore the Musconetcong River’s ecological balance and underscores the collaborative spirit between MWA, local municipalities, various stakeholders, and Princeton Hydro. It serves as a testament to the potential of concerted conservation endeavors to restore the vitality of our waterways and safeguard the natural heritage for generations to come.

The Musconetcong Watershed Association (MWA) is an independent, nonprofit organization dedicated to protecting and improving the quality of the Musconetcong River and its watershed, including its natural and cultural resources. Members of the organization are part of a network of individuals, families, and companies that care about the Musconetcong River and its watershed, and are dedicated to improving the watershed resources through public education and awareness programs, river water quality monitoring, promotion of sustainable land management practices, and community involvement. Click here to learn more.

Princeton Hydro has been working with MWA in the areas of river restoration, dam removal, and engineering consulting since 2003. Click here to read our Client Spotlight blog featuring MWA’s Executive Director Cindy Joerger and Communications Coordinator Karen Doerfer.

• Dam and Barrier
• Flood Mitigation
• Stream Restoration