Cost Minimization for Detention Basin System Design

Abstract

Detention basin is defined as a reservoir where water is stored for regulating storm water runoff. Gravity-flow outlets are used to discharge the stored runoff. A detention basin system consists of a number of detention basins which are hydraulically connected. The conventional design method for a detention basin system is often trial-and-error and time-consuming. The design by the conventional design method may not correspond to the minimal total cost for the detention basin system. The purpose of this study is to apply optimization techniques to find the optimal locations and design capacities for detention basins over a watershed such that the total cost for detention basins is minimized and the flood control objective is achieved. The total cost includes the land acquisition cost, construction cost, and maintenance cost. The flood control objective considered here is that the outflow peak discharge at the very downstream detention basin does not exceed an allowable value. A computer code is written by using MATLAB and MATLAB’s optimization tool box to solve a numerical example to illustrate the methodology. The computer code can be easily adapted to solve other similar problems.