The Susquehanna River is showing long-term reductions in nutrient pollution, according to data recently released by the U.S. Geological Survey and published by the Bay Journal.
According to the Bay Journal, the Chesapeake Bay’s three largest rivers – the Susquehanna, Potomac and James – have each shown long-term improvements in nitrogen and phosphorus trends. USGS monitoring also shows short-term improvement covering the past 10 years in the Susquehanna.
The EPA identifies nitrogen and phosphorus loadings as a “regional water quality concern,” with excessive levels negatively affecting aquatic life in the Bay. The Susquehanna contributes approximately 44% of the nitrogen load and 24% of the phosphorus load to the Bay, according to the USGS. Of the rivers flowing into the Bay, the Susquehanna drains the largest watershed, with the most farmland and most forest, and delivers more than half of the freshwater reaching the Chesapeake Bay, according to the USGS.
The improvements come as Pennsylvania and other Bay states face a heavy lift in meeting the federally mandated goals for reducing nutrient and sediment pollution in the Chesapeake Bay by 2025. Pennsylvania has developed a detailed Watershed Implementation Plan (WIP), which takes a ground-up approach with counties in the watershed establishing localized action plans for implementing farm conservation measures and other practices to meet water quality goals.
According to the Bay Journal, filling the reservoir behind Conowingo Dam has likely been a contributing factor, but scientists continue to examine data from river monitoring stations in attempts to explain the Susquehanna’s improvements. The Conowingo Dam, located near the mouth of the Susquehanna River in northern Maryland, has historically played a role in trapping nutrients and sediment before they reach the bay, but research has since found that the dam is reaching its capacity to trap pollution.