Risk Assessment and Decision-Making Based on Mean-CVaR-Entropy for Flood Control Operation of Large Scale Reservoirs

Abstract

The risk inevitably exists in the process of flood control operation and decision-making of reservoir group, due to the hydrologic and hydraulic uncertain factors. In this study different stochastic simulation methods were applied to simulate these uncertainties in multi-reservoir flood control operation, and the risk caused by different uncertainties was evaluated from the mean value, extreme value and discrete degree of reservoir occupied storage capacity under uncertain conditions. In order to solve the conflict between risk assessment indexes and evaluate the comprehensive risk of different reservoirs in flood control operation schemes, the subjective weight and objective weight were used to construct the comprehensive risk assessment index, and the improved Mahalanobis distance TOPSIS method was used to select the optimal flood control operation scheme. The proposed method was applied to the flood control operation system in the mainstream and its tributaries of upper reaches of the Yangtze River basin, and 14 cascade reservoirs were selected as a case study. The results indicate that proposed method can evaluate the risk of multi-reservoir flood control operation from all perspectives and provide a new method for multi-criteria decision-making of reservoir flood control operation, and it breaks the limitation of the traditional risk analysis method which only evaluated by risk rate and cannot evaluate the risk of the multi-reservoir flood control operation system.

Evaluation of GloFAS-Seasonal Forecasts for Cascade Reservoir Impoundment Operation in the Upper Yangtze River

“…events [3,4]. Conventionally, during wet season, reservoir operators release water preferentially for flood control [5,6] while storing water before the end of wet season to meet the demand for hydropower generation, navigation, and water supply. For full replenishment of storage, reservoir operators and academic researchers have highlighted the importance of reservoir impoundment operation and impoundment rules in several studies [7][8][9][10].Reservoir operation rules are often used to provide guidelines for reservoir operators to determine the amount of controlled discharge.…”

Dam System and Reservoir Operational Safety: A Meta-Research

“…However, the obstacles to the safety of RFCO problems are not only related to the complexity of extracting the optimal rules for RFCO operational stages but also the associated uncertainties of RFCO variables (e.g., flood peak flow) and, subsequently, the RFCO targets. Therefore, several studies considered the uncertainties in RFCO and estimated their corresponding risks to support the decision-makers in developing effective dam operational plans under various conditions [161,[167][168][169][170][171][172][173][174][175][176][177]. These uncertainties are introduced from four main sources [178][179][180]: (1) hydrological (e.g., inflow) and meteorological variables (e.g., precipitation) uncertainties that introduce randomness in flood frequency and its magnitude; (2) flood forecasting and river flood routing errors, as a result of models structure uncertainty, parameter estimation errors, imperfection of initial and boundary conditions, and simplification of the physical processes; (3) hydraulic uncertainties, such as errors in reservoir outflows (e.g., due to debris accumulations), and errors in reservoir discharge curve (i.e., the difference between actual and designed spillway capacity resulted from flow coefficients and measurement errors of the spillways); and (4) other uncertainties (i.e., deep uncertainties), such as operation time delay, human decision errors, information unavailability, poor communication.…”

Risk assessment of multireservoir joint flood control system under multiple uncertainties

“…For the deterministic operation process, the failure consequence of multireservoir flood control operation system could be defined as the excess of the security threshold during the failure period (Fu et al, 2014;Wang et al, 2019). In each simulation experiment, the failure consequence W is shown as…”