Improved Risk-Assessment Model for Real-Time Reservoir Flood-Control Operation

Abstract

This paper puts forward an improved risk assessment model for a real-time reservoir flood control operation according to the stochastic differential equation (SDE). The model is composed of three components: (1) uncertainties and risk definition, (2) SDE and reservoir flood routing, (3) and risk calculation. The first component presents the considered uncertainty factors and risks. We consider the following six kinds of uncertainties: forecast errors of reservoir inflows (IFE), reservoir outflow errors (OE), observation errors of a reservoir storage capacity curve (SOE), correlations between IFE, correlations between OE, and correlations between SOE. We consider two kinds of risks: the risk of upstream reservoir flooding at every time moment and the total risk of the flood process. The second component establishes the SDE and then conducts reservoir flood routing and derives stochastic water level errors. The third component derives calculation formulas for the proposed risks. The established model was applied to the Foziling reservoir of China. The results reveal IFE is the critical uncertainty factor, while OE and SOE are both nonnegligible in real-time operation. The risks of the reservoir increase with the uncertainty level of uncertainty factors. However, the correlation coefficient between the stochastic water level errors decreases with an uncertainty level of IFE while it increases with an uncertainty level of OE and SOE. The proposed improved risk assessment model is considered as the risk-informed tool for real-time reservoir operation.