Author(s): Miressa Ebisa Fola; Colin D. Rennie
Linked Author(s): Colin Rennie
Keywords: Hydraulic geometry; Semi-alluvial channels; Clay bed channels; Cohesive bed channels; Fluvial morphology; Geomorphology; River flow measurement; River survey; ADCP and RTK-GPS survey
Abstract: Empirical downstream hydraulic geometry equations for clay-dominated cohesive bed (semi-alluvial) streams were derived using the data from five streams in eastern Ontario, Canada and four streams from other regions. The width exponent (0.57) was comparable to the exponents reported for previous studies; however, the depth exponent (0.52) was greater for clay-dominated cohesive bed than for typical gravelbed and sand-bed rivers. To the authors' knowledge, this is the first study which related bankfull hydraulic variables and discharges to derive downstream hydraulic geometry equations specifically for clay-dominated cohesive bed streams. Furthermore, the recurrence interval of bankfull discharge of clay-bed streams was found to range from 1 to 2 years, similar to other river types. Acoustic Doppler Current Profiler (ADCP) and Real Time Kinematic Differential GPS (RTK-DGPS) were used for precise measurement of cross-section data (depth, width and area), longitudinal slope, and flow data such as discharge and velocity of large clay-bed streams. The methodologies utilized in this study such as the application of ADCP assisted by RTK-DGPS for the study of hydraulic geometry are reviewed in this paper.
Year: 2009