Accuracy of River Effective Discharge Estimation from Magnitude Frequency Analysis

摘要

Any change in the morphology of a river, other than by river engineering works, must result from a local imbalance in the sediment budget. When in regime, the river must have adjusted its bankfull morphology to transmit the total sediment load supplied from upstream, such that, over a period of years, there is no net erosion or deposition. The flow transporting the bulk of the sediment is often referred to as the effective discharge, since any change in either the flow or sediment transport regime of the river will alter its value and cause instability and adjustment to the changed condition. This has also been defined as the flow above which half of the sediment is transported, but more generally as the flow that transports most sediment originally considered by bedload and subsequently by suspended as well as total load. This paper is to adopt a standardised procedure for effective discharge estimation and also considers the factors by which this may be computed more accurately.