New Dam Removal to Curb Floods, Boost Water Quality in Musconetcong River

Jon Hurdle | November 21, 2019 | Energy & Environment, Water
Conservationists will restore river flow by removing remains of 18th-century structure
Credit: Jon Hurdle
Remains of the 18th-century Beatty’s Mill Dam, which is due to be removed next year

A sharp bend in the Musconetcong River near Hackettstown, Warren County, looks at first glance just like a natural part of the landscape, but it is in fact the result of an 18th-century dam that is now breached at one end, forcing the current to scour the eastern bank before resuming its southbound flow to the Delaware River.

The remaining part of the dam, now a mess of rubble and broken concrete, also worsens local flooding by acting as a barrier to rushing waters during big storms like Hurricane Irene in 2011, when the river peaked at 2½ feet above flood stage, forcing waters on to nearby properties.

The prevalence of local flooding, and the impact it has on river banks and floodplains, has prompted the Musconetcong Watershed Association and other local conservationists to begin a restoration program that will remove the dam and then restore 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 course.

The idea, said officials from the nonprofit and its funders at a river-bank press conference on Wednesday, is to control flooding and improve water quality and habitat for fish in a highly developed location where large areas of impervious surface have impaired the land’s natural ability to filter contaminants driven by storm water.

Credit: Jon Hurdle
Fishing on the Musconetcong River

The project has attracted $96,400 in funding from the National Fish and Wildlife Foundation under the Delaware Watershed Conservation Fund, a program that has been providing federal support for the Delaware River watershed since fiscal year 2018. With equal matching funds from New Jersey’s Highlands Council plus corporate donations, the project may become an example to other local conservation groups.

“This project was significantly strong for what it was able to do in terms of sediment removal, water quality and habitat improvement,” said Sandra Meola, director of the Coalition for the Delaware River Watershed, a nonprofit that coordinates the efforts of conservation groups working to protect the 12,755-square-mile area between New York State and Delaware.

A model for river restoration

“I would hope this would be a model for other organizations to have their ears perk up and say, ‘Hey, we have a dam downriver. Let’s get a proposal together,’” Meola said, noting that NFWF is expected to release the next request for proposals in February 2020.

The latest money comes from a program that has so far funded 55 projects in two rounds, totaling $6.9 million, Meola said. The grants are awarded for projects that protect fish and wildlife habitats, improve water quality, and promote public access.

Alan Hunt, the association’s executive director, said flooding churns up sediment in the water, covering the rocky habitat favored by fish and cutting the number of macroinvertebrates that they feed on.

“By taking out this remnant dam, we are reducing the flooding risk upstream, improving the river-bottom habitat and water quality,” he said. More fish would also bring more fishermen and women, Hunt said, as a lone fisherman cast his line in a pool beside the dam.

The dam, named after the former Beatty’s Mill, will be the sixth to be removed by the association since 2008, but it is far from the last in the 157-square-mile watershed that stretches from Lake Hopatcong to the Delaware River opposite Riegelsville, Pa.

Credit: Jon Hurdle
Alan Hunt, executive director of the Musconetcong Watershed Association, which is leading a project to restore a section of the river.

The group chose Beatty’s Mill for its latest project because it was a good fit with the earlier projects, Hunt said. It was also more achievable than the next dam downstream, which has been a longstanding barrier to shad as they swim upstream to spawn each spring, but represents a far bigger challenge than the current project.

“We thought, ‘This is a great skillset we have, around dam removals and river restoration. Where else would it be beneficial for us to do this work?’” Hunt said.

The Beatty’s Mill Dam was chosen also because it worsens flooding in one of the most populated parts of the watershed, and because the project was doable with the available funding, Hunt said.

A team effort

Hunt’s association will work alongside other members of the Musconetcong River Restoration Partnership — made up of private dam owners, funders, engineering firms, regulators and nonprofits — which has become a best practice for this type of river restoration, Hunt said.

Curbing floods will also help to avoid significant traffic disruption, said Matthew Murello, mayor of Washington Township, which lies to the south of Hackettstown. “This is one of our pinch points where we’ve had flooding in the past,” he said.

The project is still in its design phase and is expected to begin implementation in 2020, said Kyle Richter, the association’s watershed programs coordinator and head of the new restoration project.

When complete, it aims to restore 2.5 acres of flood plain; stabilize 0.15 mile of stream bank; restore 0.15 mile of stream bed, and reduce total suspended solids in the water by 20%. With that work, officials hope to improve the water’s pH, temperature and dissolved oxygen, creating better conditions for fish such as Eastern brook trout and American eel.

Richter hopes to repeat the success of previous dam-removal projects along the 43-mile river. These efforts have reduced flooding, lowered water temperature and cut the amount of sediment flowing into the river or its tributaries. “It’s been a great asset to the river,” he said.