SUSPENDED SEDIMENT BUDGET FOR CHESAPEAKE BAY

ABSTRACT The Susquehanna is the only river that discharges directly into the main body of the Chesapeake Bay. All the other rivers flow into tributary estuaries and most of their sediment loads are entrapped within these estuaries. During periods of high riverflow the Susquehanna dominates the upper 20-30 km of the Bay; the net flow and sediment transport are seaward at all depths, and there is a marked downstream decrease in suspended sediment. With subsiding riverflow, a turbidity maximum is formed in the upper reaches of the Bay. In the middle and lower reaches of the Bay, shore erosion is not only a major source of inorganic sediment it may be the largest single source. The distributions of suspended sediment along the axis of the entire Bay are presented for a twelve month period in 1969-1970. These data, and others, were used to formulate a single-segment model of the main body of the Bay that indicates that there is a net movement of sediment into the Bay from the ocean, and that the tributary estuaries are sinks for suspended sediment in the Bay.