Although sediments are a natural part of the Bay ecosystem, accumulation of excessive amounts of sediments is undesirable. Accumulation of -sediments can fill in ports and waterways. This sedimentation process already has caused several colonial seaports, like Port Tobacco, Maryland, to become landlocked. As they settle to the bottom of the Bay, sediments can smother bottom-dwelling plants and animals, such as oysters and clams. Sediments suspended in the water column cause the water to become cloudy, or turbid, decreasing the light available for underwater Bay grasses .
Sediments also can carry high concentrations of certain toxic materials.
Individual sediment particles have a large surface area, and many molecules easily adsorb or attach to them. As a result, sediments can act as chemical sinks by adsorbing metals, nutrients, oil, pesticides and other potentially toxic materials. In the upper Bay and tributaries, sediments are fine-grained silts and clays that are light and can be carried long distances. These sediments are carried by the fresh, upper layer of water. As they move into the Bay, the particles slowly descend into the denser saline layer.