A Unified Framework for Deriving Extremal Hypothesis Theories of Hydraulic Geometry

Effects of initial and boundary conditions on gravel-bed river morphology

“…Stable channels, having reach-averaged geometry that can be considered constant, belong to river reaches in morphodynamic equilibrium. The geometry of stable river channels has been described using the regime theory (Kennedy, 1895;Lacey, 1930;Leopold and Maddock, 1953;Parker et al, 2007), extremal hypothesis (Griffiths, 1984;Singh, 2003) and mechanistic approaches (Parker, 1978b). Several empirical relations have been formulated to determine the reach-averaged channel width and depth as a function of bankfull discharge (Leopold and Maddock, 1953;Williams, 1978;Parker, 1979;Emmett and Wolman, 2001) or as the formative discharge having a certain return time, normally 1.5 to 2 years (e.g.…”