Dam Removal

Removing old dams helps to restore migratory fish, clean water, and recreation.

Since the 18th century, dams constructed along the Millstone and Raritan Rivers have blocked American shad, striped bass, herring and other fish from swimming upriver to reproduce. Although these dams are relatively small and may seem insignificant, they prevent fish migrations and can also have a pronounced negative impact on water quality by blocking water flow, trapping sediment, and changing in-stream habitat. The dams can also be very dangerous for recreational users of these rivers, who can become trapped in the hydraulic jump at the base of the structures and drown.

Many low-head dams are now obsolete and crumbling before our very eyes, so it’s a good time to remove them from our rivers. In 2008, the Watershed launched an effort to remove the Weston Mill and Blackwells Mills Dams on the Millstone River. We’ve completed feasibility studies and hydrologic analyses, secured a number of required permits and advocated with NJDEP and others to make this a priority.

The Watershed is a partner in the Raritan Basin Fish Passage Initiative. Since 2011, three dams have been removed from the Raritan River, restoring more than a dozen miles of migratory fish habitat and providing passage from Raritan Bay to the Millstone River for the first time in more than 80 years.



The Lower Millstone River is the final stop for waters in the Stony Brook-Millstone Watershed before they converge with the Raritan River and Raritan Bay. What happens here can be indicative of how the rest…


The dam’s removal will restore historic migration routes for American shad and other fish that have been blocked for nearly three centuries from the Millstone…

Weston Causeway Dam

In 2016, the National Oceanic and Atmospheric Administration’s Fisheries Division (NOAA Fisheries), in coordination with the US Fish and Wildlife Service and NJ Department of Environmental Protection agreed…