Verification of interpolated variance estimate method for discharge measurements in Yangzte River Basin, China

There are more and more attentions on the importance of estimating the uncertainties in discharge measurements. However, for most of the existing methods, they typically identify various sources of uncertainty and then estimate the uncertainty from each of these sources by applying the results of empirical or laboratory studies. The interpolated variance estimator (IVE) is a new method which can estimate the uncertainty based on direct discharge measurements. The aim of this study is to verify the reliability of the IVE method by applying to the Yangzte River Basin in China, and to quantify the uncertainties in the discharge measurements. The ISO method and the method in Chinese standard have been used as the benchmark methods for the verification. The Monte-Carlo experiments have also been designed to simulate the discharge measurements in a hypothetical channel. The results of this study show that the IVE method is a useful method for estimating the uncertainties of the discharge measurements using the velocity-area method, especially if there are many verticals and points used in the measurements in a channel cross-section. Also, the IVE method is a good method for use if the Type B evaluation methods are inappropriate.