MEASUREMENTS OF EROSION OF UNDISTURBED BOTTOM SEDIMENTS WITH DEPTH

A unique flume that measures the erosion of sediments at high shear st resses and with sediment depth has been designed, constructed, and use d. Experiments in this flume, Sedflume, can be done either with recons tructed sediments or with relatively undisturbed sediments from the fi eld. With either kind of sediment, two different types of experiments can be conducted. The first type determines the critical stress for er osion of the sediment as a function of depth, while the second type de termines the erosion rate of the sediment as a function of both shear stress and depth. Measurements of the erosion rates of sediments from the Trenton Channel of the Detroit River in Michigan and the Lower Fox Fiver in Wisconsin were made by use of Sedflume at sediment depths up to 2 m. Representative results of these measurements are presented he re. These results demonstrate the capabilities of Sedflume and also il lustrate the large differences in erosion rates at different sites and the large variations in erosion rates with depth and as a function of shear stress.