Reconnaissance Report. Sedimentation Problem, Quincy Bay, Illinois

摘要

Quincy Bay is a complex backwater area along the Mississippi River adjacent to the city of Quincy, IL. The change in water flow patterns and sediment accumulation following the construction of Lock and Dam 21 in the 1930's and, more recently, the opening of a small-boat access channel in the late 1960's have caused concern. This report summarizes existing data and outlines proposals to enhance recreational opportunities and to reduce the rate of sedimentation in Quincy Bay. The most effective way to reduce sedimentation in the bay area would be to construct a levee from the railway embankment upstream to the Indian Grave Drainage District levee. This levee would close the upper Quincy Bay access channel and greatly reduce sedimentation from high flows on the Mississippi River. Upper Quincy Bay access channel is to remain open, dredging would be required for boat access in the near future. A channel restriction consisting of a submerged rock dike across the upper reach of the access channel is expected to reduce the sediment load the channel is presently carrying. (edc)