Project Description
The 38.6-mile Millstone River is a major tributary of the Raritan River. Since the 18th century, dams were constructed throughout the watershed creating barriers that prevented anadromous fish from reaching their spawning habitats. Located approximately 1.5 miles upstream of the Millstone River’s confluence with the Raritan River, the Weston Mill began operating in the mid-1700s when a dam was constructed to power a grist mill and sawmill. Major improvements are believed to have been made to the colonial-era mill and dam in 1803, and the original dam was replaced with a timber crib dam in 1844. The mill operated under several private owners and corporate entities until Wilbur Smith acquired the property in the 1920s. Significant structural repairs were made to the dam, including capping the timber crib dam with concrete, between 1922 and 1948 before it was abandoned and fell into disrepair. A portion of the mill building collapsed in 1982 and burned down the following year due to arson. In 2015, the eastern portion of the dam crest began to collapse, redirecting the flow toward the eastern bank. In addition to blocking fish passage, the 5.5-foot-tall low-head dam was a hazard to public safety and downstream infrastructure.
In August 2017, the U.S. Fish and Wildlife Service (USFWS), New Jersey Department of Environmental Protection (NJDEP), and National Oceanic and Atmospheric Administration (NOAA) removed the Weston Mill Dam from the Millstone River. An initial 35-foot notch was cut near the center of the dam to draw down the impoundment. Once the impoundment was drained, a saw cut was made to separate the concrete apron from the mill foundation wall, and the apron and dam were carefully removed. Several timbers from the historic timber crib structure were saved and donated to Delaware and Raritan (D&R) Canal State Park, NJDEP, and the Borough of Manville, and riprap was placed around the mill foundation walls to protect the site for future archaeological studies. The removal of the Weston Mill Dam allowed migratory fish to access approximately 4.5 miles of the Millstone River that had been blocked for almost three centuries. In 2018, five juvenile American shad were found near the base of the Blackwells Mills Dam, the next impediment to fish passage upstream, indicating that shad are successfully spawning in the Millstone River. This project was funded by the Natural Resource Damage settlement from the American Cyanamid Superfund Site.
Parties Implementing Restoration
New Jersey Department of Environmental Protection; NOAA
DOI Project Representatives
Fish and Wildlife Service