Effects of Drawdown and Structures on Bed-Load Transport in Pool 8 Navigation Channel

Abstract : This Coastal and Hydraulics Engineering Technical Note (CHETN) describes the progress made in using multibeam bathymetric data to determine the effects of a pool drawdown and structures on bed-load transport in the Pool 8 navigation channel. Work was conducted as part of the Monitoring of Completed Navigation Projects (MCNP) program. BACKGROUND: The channel training stnicflires (wing dan%s and closing dan%s) that are cun%ntly in place on the Upper Mississippi River were constnicted more than 100 years ago to increase flow in the navigation channel and cause scour to occur resulting in a deeper chatitiel. Initially, these stnicflires accomplished this goal as evidenced by the islands and sandbars which foniied around them. Constniction ofthe locks and dams, 60 years ago, submerged the flaining sfi%cttires, reducing their effectiveness and increasing secondat'y channel and floodplain conveyance. Both flaining sti%icflire submergence and floodplain conveyance are a ft'nction of longiflidinal position within the pool, generally increasing from the upstream to the downstream end of the pool.