Project Description
The Cole's Mill Dam in Califon, NJ (also known as the Califon Dam) was constructed between 1830 and 1840 to provide power to a small gristmill along the South Branch Raritan River but fell into disuse and was considered obsolete by the end of the century. Most dams in New Jersey are well over 100 years old, no longer used, and at risk of falling into disrepair. This combination often leads to unwanted maintenance costs and potentially unexpected structural failures. The Cole's Mill Dam forms a 7-acre mill pond that has become shallow over the years due to sedimentation. During the summer months, water quality conditions are degraded due to high temperatures, excessive aquatic plant growth, and low dissolved oxygen levels, creating unsuitable habitat for many species of fish and other aquatic organisms. In 2018, ice damage created a 30-foot breach in the dam, altering the river’s watercourse and causing erosion that may eventually undermine a section of Raritan River Road. As a result, the NJDEP Bureau of Dam Safety issued a notice to the owner that the dam must be repaired or removed.
The Cornell-Dubilier Electronics Trustees have proposed a restoration project to remove the Cole's Mill Dam. This project, once complete, will improve fish passage for resident and diadromous species such as American eel, improve water quality and lower water temperatures for eastern brook trout and other coldwater species, and potentially alleviate flooding in the surrounding community. Once removed, aquatic connectivity will be restored for over 16 miles from the Lake Solitude Dam to the Nunn's Mill Dam. A component of the project will include restoration of the natural floodplain and riparian areas, creating additional habitat for migratory birds and other wildlife species. This project will also increase recreational fishing opportunities at the site and downstream at the Ken Lockwood Gorge, as the South Branch is a popular destination for trout anglers. The project will include completing a feasibility study, design, permitting, construction, and pre- and post-restoration monitoring.
Parties Implementing Restoration
New Jersey Department of Environmental Protection; NOAA; Raritan Headwaters Association; U.S. Fish and Wildlife Service
DOI Project Representatives
Fish and Wildlife Service