Hydrologic and Geomorphic Aspects of High-magnitude Floods on the Par River in Western India

Abstract

The geomorphic effectiveness of floods is evaluated in terms of unit stream power (ω) and boundary shear stress (τ) for floods on the Par River. The highest values for ω and τ for a flood on the river are 52125 W/m2 and 3320 N/m2, respectively. The estimated Froude numbers are <1 indicating subcritical flows. It is >1 for a few constricted reaches showing supercritical or shooting flows. High values of Reynolds number reveal that the flood discharges were extremely turbulent. Values of critical velocity for the inception of cavitation (Vc) show that none of the powerful floods on the river, except two, exceed the conditions. Estimates of ω, τ and velocity associated with transported boulders indicate that all floods were competent to move large boulders of more than 5.5 m in diameter. The efficiency of high-magnitude flood events is evident from the presence of a variety of geomorphic features.