Risk-benefit decision evaluation on flood control operations based on subjective-objective integrated weighting

To address the decision-making challenges in flood control scheduling for complex water projects, an integrated subjective-objective weighting risk-benefit evaluation and decision-making model based on AHP-CRITIC-TOPSIS was proposed. Taking the flood control scheduling simulation for the Changjiang River Basin from July 28 to August 2, 1954, as a case study, a risk-benefit index system for flood control scheduling was constructed. The AHP-CRITIC method was used to collaboratively optimize index weights in an "experience-oriented and data-driven" manner, and the TOPSIS method was applied to evaluate the effectiveness of joint flood control scheduling schemes for water projects. The results show that there is trade-offs among risk-benefit indicators, with the affected population indicator receiving the highest weight of 0.251 3. The combined weighting approach effectively integrates expert decision preferences and empirical experience. Compared with Scheme 1, the recommended optimal Scheme 3 reduces the downstream excess flood volume by 5 billion cubic meters, decreases the affected population by 1.208 million people, and reduces inundation losses by 23.2 billion yuan, at the cost of lowering flood control capacity by 7.63 billion cubic meters. The findings can provide a reference for evaluating regulation effectiveness and optimizing joint flood control scheduling schemes for complex water engineering projects.