Economic Principles and Optimal Rules for Flood Detention Basin Operation

Abstract

Flood detention basins (FDBs) are critical infrastructure for mitigating downstream flood risk through temporary floodwater storage and are widely implemented globally. However, with ongoing economic development within FDBs, balancing the safety of downstream flood protected areas with the internal economic losses of FDBs is a significant challenge, requiring a fundamental theory and quantitative rules for optimizing the flood diversion operations. This study develops a theoretical optimization model for FDB operation. We analytically derive economic principles for the optimal allocation of flood discharge between the FDB and the downstream protected area for various inflow cases with corresponding optimal rules proposed. A key control indicator is derived, named the Risk‐Adjusted Safety Threshold for the downstream protected area, which governs the activation and magnitude of flood diversion. We verify that the proposed optimal rules can reduce the total economic losses in a real FDB case in China. Additionally, the effects of key parameters, including physical constraints, hydrologic forecast uncertainty and economic losses, on optimal operation effectiveness are explored. The proposed economic principles and optimal rules for FDB operation can also offer valuable insights for flood risk management across various areas.