Analysis of erosion rate and shear stress based on soil type

Erosion is a ubiquitous phenomenon which occurs when shear stress exceeds the forces keeping the particle in place. Shear stress is changed significantly when the flow is changed from its normal conditions by changes in hydrologic conditions. Soil erodibility is an estimate of the ability of soils to erode, based on the physical characteristics of each soil. The resisting force of soil depends on many parameters and the variability of each parameter introduces variations in the erodibility. The determination of erosion potential at selected river reach requires knowledge of flow conditions, soil composition of the cross sections and erosion rate for the soils present in the cross section. The objective of this research is to experimentally determine the erosion vs. shear stress rates which produce the erosion of most common types of soils that are present along the creeks of Metropolitan Saint Louis Sewer District service area. Samples were collected from banks of creeks using thin-walled shelby tubes which gives practically undisturbed soil sample for the experiments. The experiments were performed in a laboratory recirculating flume, which is designed and constructed at UMR hydraulic laboratory to measure the erosion rates of soil samples. Statistical analyses were performed on the results to obtain the shear stress vs. erosion and critical shear stress values of three soil types --Abstract, page iii