Multi‐objective reservoir operation under emergency condition: Abbaspour reservoir case study with non‐functional spillways

The main objective of this study is to present a simulation‐optimization approach methodology for short‐term operation of multi‐objective reservoirs during emergency conditions where risk of flooding and overflow from damaged spillways is significant. The paper considers flood risk management through enhancing dam safety as well as long‐term objectives of the reservoir for hydropower generation and irrigation water supply simultaneously. In particular, real‐time operation of A bbaspour reservoir during an emergency condition is considered where all flood discharging facilities are out of order for repairing the damaged parts. The proposed methodology combines a short‐term and a long‐term operation strategies to minimize risk of overflow for any possible incoming floods while preserving the long‐term objectives of the reservoir. An efficient daily flow forecasting scheme provides the inflow data for the short‐term (daily) operation strategy in a deterministic environment which follows the long‐term operation policy. A multi‐objective stochastic dynamic programming model addresses the long‐term operation policy by solving the weekly operation model. The outcomes of the model application to the case study have illustrated its capabilities in developing a compromise between the risk of dam overflow and its long‐term objectives.