Basic hydraulic variables, such as water discharge and flow shear stress, are derived from velocity profiles assuming that their shape is logarithmic. Recent studies have demonstrated that velocity profiles in coarse bedded streams are often not logarithmic but segmented or S-shaped. This doctoral dissertation research will focus on the various factors affecting the shape and spatial variation of velocity profiles in natural streams with coarse bed material. In this project two sets of data will be collected on velocity profiles: one set of measurements from 10 natural coarse bedded streams in New York and Quebec and the other set from a flume with a bed of coarse material in the Hydraulics Laboratory at the State University of New York at Buffalo. Respectively, these two sets of measurements will permit the elucidation of the effect of varying bed roughness on the shape and spatial variation of velocity profiles and the examination of the effect of variables such as channel slope that are difficult to isolate in the field. These two complementary sets of field and laboratory data will make possible the more accurate estimation of water discharge, bed sediment entrainment, and bed sediment transport rates. This research will contribute to a better understanding of flow and resistance in channels with large roughness elements. The solutions to many problems in geomorphology, engineering, and environmental science encountered in the exploitation of surface water resources depend upon developing more accurate flood routing models and sediment transport models. The project also will provide an excellent opportunity for a promising young scholar to continue to develop independent research skills.
