Multiobjective watershed-level, planning of storm water detention systems

Detention basins are the most popular structural measure for urban flood control and have proven effective for both water quantity and quality management. Integrated, watershed-level planning of the layout and sizing of detention systems is essential because localized solutions may actually aggravate the negative impacts of urban drainage. Successive reaching dynamic programming (SRDP) is applied to minimize detention system costs of maintaining ranges of desired downstream peak flow attention, with basin and channel routing imbedded within the algorithm. A multiobjective genetic algorithm (MOGA) is also applied to generating nondominated solutions for system cost and detention effect for a watershed-level detention system. These algorithms are applied to the layout and design of a stormwater detention-system in the Pazam watershed located in southern Taiwan. The case study confirms the robustness and computational efficiency of the SRDP algorithm, and the MOGA generates a wide range of nondominated solutions for trade-off analysis using a proposed élite solutions conservation procedure.