Experiments on Sediment Exclusion from Marinas and Harbors

Sediment clogging in marinas is a problem throughout the world and leads to the loss of functionality of the marina and loss of revenue in terms of shipping and recreational value. Although no methods exist for completely keeping sediment out of marinas, laboratory experiments were carried out here to test various approaches. What makes it so difficult to exclude sediment from marinas is that sediment can enter from all directions: not only from along the shores but also from waves at various angles. Several methods were modeled here for longshore currents, including (1) an Accelerator Wall, (2) a Break-Accelerator Wall, (3) a Break-Guide Wall with Downstream Entry, and (4) a Break-Guide Wall with Lakeside Entry. Experiments were performed in an experimental channel in which the flowrate, velocity, flow depth, and sediment could be varied. Velocity values and flow depth were measured for the various cases tried. In addition, sediment behavior was observed. Under the tested laboratory conditions, it was found that the configurations with accelerator walls did not exclude sediment from entering the marina in any of the cases and, therefore, should not be used. Both break-guide wall configurations did exclude sediment from entering the marina. The break-guide wall would not be subject to wave sediment while the one with a gap could be.