An alternative measure of discharge effectiveness

Since 1960, geomorphic effectiveness has been quantified by analytically combining measures of the frequency and the magnitude of geomorphic processes, most often for the case of sediment yield in rivers via the calculation of effective discharge, Q(eff). Here we leverage the Q(eff) analysis approach to develop an alternative metric, the functional-equivalent discharge Q(fed), which is the discharge that will reproduce the magnitude of the sediment load generated by the full hydrologic distribution. Q(fed) is intended to be a more representative metric of hydrologic variability than Q(eff): whereas Q(eff) provides a measure of the effectiveness of individual flow rates, Q(fed) incorporates a measure of the average effectiveness of the entire flow distribution. We develop an analytical approximation of Q(fed) based on relatively few parameters, apply the approach to a set of suspended sediment load data and describe how Q(fed) varies broadly with sediment and hydrologic conditions. Copyright (C) 2007 John Wiley & Sons, Ltd.