Restoring the Paulins Kill River

Restoring a river means tackling challenges methodically and bringing stakeholders like conservation organizations, farmers, business owners and private and public landowners together to address the river’s challenges and strategically advance a shared vision to protect it.

The Nature Conservancy is leading a team that includes local organizations and public and private supporters to rejuvenate the Paulins Kill and the flow it delivers into the Delaware, which provides drinking water for more than 17 million people every day.

The Nature Conservancy and partners have removed four key dams along the Paulins Kill River: the Columbia Dam and its remnant in Knowlton, removed in 2019; the County Line Dam in Stillwater, removed in 2022; and the Paulina Dam in Blairstown, removed in 2024.

The Columbia Dam and the Paulina Dam were sizable structures that impounded large areas of water, with the Columbia Dam spanning 330-ft wide and 18-ft tall, with a 32-acre impoundment; the Paulina Dam spanning 200-ft wide and 13-ft tall, with a 35-acre impoundment; and the County Line Dam spanning 230-ft wide and 4-ft tall. All of the dams had a negative impact on the river, acting as barriers to fish migration, disrupting the natural flow of the river, and decreasing the water and habitat quality for resident and migratory species.

Among the many challenges the Paulins Kill faces is that significant parts of its floodplain—critical land around the river’s banks—have been deforested and left without trees that help filter water, absorb flooding or cool the river for fish. We reforested 10 miles of river and, with the help of local landowners and residents, have planted more than 58,000 trees to date. 

The Hyper-Humus section of the Paulins Kill Wildlife Management Area, not far from the river’s headwaters, was mined for peat for more than 75 years. More than 2.5 miles of river and floodplain were ditched and drained, creating a host of ecological challenges, including stagnating water, altered habitat and water too warm for native fish.

We are working to restore the river channel and its connection to the floodplain, which will help absorb floodwaters, improve water quality and temperature, and create a variety of recreational possibilities at the site.

Built into our plans in the Paulins Kill is measuring how much we have improved the river’s health, to gauge how well the restoration is working. Our conservation scientists are monitoring water quality in priority areas of the Paulins Kill and using the results to set benchmarks and measure impacts of our work.

We are surveying for freshwater mussels and other important macroinvertebrate species, such as larval dragonflies, damselflies, caddisflies, stoneflies and mayflies. These species are important indicators of watershed health and river condition.

The data we collect will provide a baseline against which to compare conditions over time as our conservation projects mature. We share this data with partners and other groups working in the Paulins Kill to inform future management and conservation efforts.

We are already observing encouraging trends in the data related to our conservation efforts in the Paulins Kill. Macroinvertebrate populations are both abundant and diverse, particularly in the lower section of the river near the former Columbia Dam site. Following the dam’s removal, water temperatures upstream and downstream have become more consistent—likely due to the elimination of the impounded area, which previously slowed the flow and allowed water to warm before cascading over the dam.

With all four removals, we have successfully documented migratory fish like American shad and sea lamprey migrating up to the farthest upstream reach on the Paulins Kill.