Optimal Estimation of Storage-Release Alternatives for Storm-Water Detention Systems

Abstract

A heuristic optimization methodology is developed for obtaining the optimal allocation of storage capacity and release rate for the design of storm-water detention facilities. The nonlinear optimization procedure is formulated within the framework of production function theory. The model is set up in terms of a nonlinear cost-objective function with a technological production constraint, which is the storage/release isoquant defining runoff volume or pollutant load trap efficiencies. The process constraint is expressed as a function of the design variables of storage capacity and release rate, in terms of runoff process statistical parameters and desired trap efficiency. The analytical structure of the model allows the use of marginal analysis in obtaining the least cost solutions of storage capacity and release rate for any level of pollutant trap efficiency. It also allows prompt assessment of sensitivity, resiliency, and variability of pollutant loading rates. The methodology is applied to a catchment in Minneapolis.