Susquehanna River

For thousands of years, the migratory journey of the American shad marked the coming of spring on the Susquehanna River. Schools of this silvery fish – which spend most of their adult lives in the open Atlantic – made their way through the Chesapeake Bay and into the river on spawning runs that became legendary for their numbers.

In colonial times, the Susquehanna River had the largest American shad run on the East Coast, and just about every town along the river has some history tied to shad fishing. These spawning runs continue today, but they’re not what they used to be. Over the years, major hydroelectric dams along the lower Susquehanna have blocked shad runs and American eel migration and have altered habitat for a host of other wild creatures as well. As the dams were constructed, annual shad catches in Pennsylvania fell to 33,000 pounds in 1915 from an average of 252,000 pounds, and then dropped to nothing by 1928.

But the dams, and other man-made changes to the Susquehanna watershed, have done more than interrupt the migration patterns of shad; they also threaten an iconic river that is important to millions of people throughout Pennsylvania and Maryland.

River of Life

The Susquehanna, the 16th largest river in the United States, supplies drinking water to hundreds of thousands of Pennsylvanians along its reach. It offers recreational opportunities and industrial water supplies. It boasts a well-known smallmouth bass fishery, and is popular with boaters and birders. Unseen to most visitors, millions of freshwater mussels, some of them seriously threatened, line the river bottom.

The health of the river also affects the biology downstream in the Chesapeake Bay, the nation’s largest estuary, which relies on fresh water from the Susquehanna to maintain its ecological equilibrium. Freshwater is a vital part of what makes the Chesapeake Bay tremendously productive, and half that freshwater comes from the Susquehanna.


The Susquehanna faces a variety of serious and growing threats, as human demands for water outstrip nature’s ability to provide. Poorly-planned development, agriculture, and oil and gas drilling threaten both water quantity and quality. These demands have the potential to threaten the natural rhythms of flood and drought that are critically important to freshwater life.

Taking Action

The Nature Conservancy stands hip deep with our partners in conservation of the Susquehanna and its tributaries, using the best available science to find a reasonable balance between the needs of people and nature. The Conservancy is framing an approach to conserving the Susquehanna aimed at supporting existing efforts, and tackling the key threats that challenge the entire watershed.

Over the past year, the Conservancy has taken action on a number of fronts to protect and restore natural water flow patterns. The Conservancy is working to make sure that fish-passage and other wildlife issues are considered during the current federal re-licensing of the Conowingo Dam on the Susquehanna River. We’re working with the Susquehanna River Basin Commission (SRBC) and the U.S. Army Corps of Engineers to identify the amounts and timing of flow needed to sustain aquatic species and habitats throughout the Susquehanna basin, and to maintain the health of the Chesapeake Bay.

These efforts were recognized recently by the SRBC, which presented the Commission’s seventh William W. Jeanes, Sr. Award for Environmental Excellence to The Nature Conservancy for its past and current work to protect water quality in the Susquehanna watershed.