Optimal design of interception for flood control: An integrated simulation approach

Abstract

This study develops a computational framework that integrates a flood simulation model, a response surface method, and an optimization technique for an optimal flood control design. The objective function was the minimization of the difference between simulated flooding depths and pre-specified allowable flooding depths, with simulated flooding depths constrained to less than allowable flooding depths in the control regions. The design variables were the design capacities of hydraulic structures. The flood simulation model was based on two-dimensional shallow water flow equations for open channel flow, rainfall, overland flow flooding, and river interactions. The response surface method was combined with the central composite design method to construct approximate functions for the objective and the constraint functions in terms of the design variables. Sequential quadratic programming was used to obtain the optimal design variables with the minimum value of the approximated objective function. Actual flood data from Typhoon Morakot for the Linbian River was used to verify the flood simulation model. The integrated computational framework was then used to calculate the optimal upstream interception strengths for controlling downstream flooding under hydrologic conditions associated with a 100-year return period storm. Numerical examples demonstrated that the proposed computational framework can efficiently provide optimal designs for practical flood control problems.