Heavy rainstorms flood Chesapeake Bay with nutrient, sediment pollution

Early March's heavy rains and snow melt caused a flood of nutrients and sediment to flow into the Chesapeake Bay from the Susquehanna River, according to scientists with the Maryland Department of Natural Resources.

This heavy runoff, which resulted in record poor water clarity in many areas, could harm bay grasses and cause more algae blooms to form in the Bay this spring and summer, especially if the wet weather continues.

Two days after a very heavy rainstorm that doused the region with 2+ inches of rain, the U.S. Geological Survey recorded a peak flow of 485,000 cubic feet/second (cfs) from the Susquehanna River at Conowingo Dam. This was well above the March average of 75,000 cfs and the highest average daily flow rate observed at the dam since September 2004, when floodwaters from Tropical Storm Ivan passed through.

Large amounts of fresh water flowing from the Bay’s rivers can erode stream banks and bring polluted runoff from the land into the Bay. Late winter and early spring are critical times for many of the Bay’s aquatic species. Bay grasses are just beginning to grow and many fish are starting to spawn.

Maryland DNR will continue to monitor water conditions to assess any short- or long-term storm effects of the wet weather.

For more information, visit Maryland DNR's website.