Risk-Cost Optimization of Hydraulic Structures: Methodology and Case Study

Simultaneous consideration of initial construction cost and failure risk in practical design of critical hydraulic structures is a long-standing problem in water resources planning and management. Despite extensive efforts to effectively tackle this problem during recent decades, the traditional rather inefficient technique of return period approach still enjoys being the dominant technique in real-world projects. Accordingly, this article aims at developing an innovative evolutionary-computation-based multi-objective model as a remedy to shortcomings of existing common methods. This simulation-optimization framework generates a series of uniformly distributed trade-off solutions which represent the compromise between competing objectives of construction cost and failure risk. Hydrologic and hydraulic uncertainties along with flood routing process are considered in the optimization process to provide a more complete picture of the problem. This approach is demonstrated and discussed for flood diversion system of Bakhtiari Dam in Iran and the Pareto optimal fronts are found for different combinations of uncertainties. The presented multi-objective approach can effectively enlarge the decision maker's scope to more efficiently determine the optimum design of the system.