A methodology for optimal operation of pumping stations in urban drainage systems

Over the past two decades, flood risks have presented a significant challenge for urban areas owing to the increased peak flows resulting from urbanization and climate change. In metropolitan areas, large-scale networks of sewer pipes and pump stations are the main facilities used to mitigate flood damage. During flooding periods, when drainage gates are closed, pumping operations play a major role in efficiently reducing flood damage. To obtain an optimal policy for these operations, a novel robust approach is presented here. In this approach, a long-term operating rule is designed by coupling a mathematical model and a new hybrid harmony search algorithm, while considering the stochastic nature of rainfall events. Application of the proposed method to a real urban drainage system showed a high efficiency in terms of flood mitigation and performance of pumps compared to the current operating rule for the pump station. Compared to the traditional approach, optimal operation decreased peak water levels by an average of 40%, without increasing the number of pump switches. Based on these results, optimizing pumping operations appear to be a practical and highly effective way to reduce flood water levels and urban inundation without making changes to the actual infrastructure of the system.