Conowingo Watershed Implementation Plan

The Conowingo Dam, located in Maryland, was constructed in 1928 and is the most downstream of four hydroelectric dams on the lower Susquehanna River. The Susquehanna River watershed encompasses approximately 27,500 square miles across Pennsylvania, New York, and Maryland and contributes roughly 43 percent of the freshwater flow to the Chesapeake Bay. Historically, the dams trapped and stored significant amounts of sediment and nutrients. However, studies have shown that the Conowingo Dam has reached a state of dynamic equilibrium, meaning accumulated sediment has substantially reduced the dam’s capacity to retain additional sediment and associated pollutants.

In 2019, the Chesapeake Bay Program awarded a multi-year grant to CWP to develop and coordinate implementation of a plan to address the additional nutrient and sediment reductions needed to achieve Chesapeake Bay restoration goals in light of the dam’s diminished trapping capacity. CWP led this work in partnership with the Conowingo Watershed Implementation Plan (CWIP) Steering Committee, Chesapeake Conservancy, and the University of Maryland Sea Grant Extension. The CWIP was founded on a collaborative, watershed-wide approach in which jurisdictions throughout the Susquehanna River basin worked together to achieve pollutant reductions by targeting the most effective and cost-efficient practices. The CWIP establishes a strategy to prevent more than six million pounds of nitrogen from entering the Chesapeake Bay annually, with an estimated implementation cost of $53.3 million per year.

CWP prepared the CWIP; finalized geographic and sector-specific pollutant reduction responsibilities; established the implementation schedule; developed targeting strategies for nutrient and sediment reduction practices; and conducted stakeholder outreach and engagement. CWP also led the preparation and refinement of the Two-Year Milestones, developed and submitted progress reports to EPA and Chesapeake Bay Program partners, and prepared future milestone commitments. To support implementation tracking and communication, CWP developed project tracking tools, produced newsletters highlighting progress and accomplishments, and provided ongoing facilitation and presentations at CWIP Steering Committee meetings. Through these efforts, CWP helped coordinate multi-state collaboration, track progress toward implementation goals, and advance nutrient and sediment reduction efforts across the Susquehanna River watershed.

For more information about this project, contact Amanda Pollack at ahp@cwp.org.