Sediment

8.5 million metric tons (18.7 billion pounds) of sediment is believed to enter the Bay every year.  The sediment enters the Bay through flows from its tributaries and from shoreline erosion and run-off, with over 60% washing off of farmland.  In addition, a tremendous amount of sediment exists on the banks and floors of streams that feed into the Chesapeake Bay, an almost impossible-to-control source referred to as Legacy Sediment.  Urban runoff and Legacy Sediment contribute about 18% of total sediment pollution to the Bay.

One major challenge facing the Bay is the huge amount of sediments trapped behind the Conowingo Dam on the Susquehanna River. Once the reservoir behind the dam has completely filled, there will be a tremendous increase in the amount of sediment reaching the Bay.