Optimal Real-Time Operation of Multipurpose Urban Reservoirs: Case Study in Singapore

The sustainable urban water management paradigm is based on the idea that water supply, storm water drainage, and wastewater disposal are interrelated resources that can increase the sustainability at the urban scale. In this context, the construction of reservoirs mainly fed by storm water and operated for drinking supply purposes can be demonstrated to achieve long-term sustainability objectives. However, the operational management of reservoirs located in urban areas faces a number of challenges due to the high hydraulic efficiency of urban catchments, i.e.,short time of concentration, increased runoff rates, and losses of infiltration and baseflow. With the purpose of discussing the best alternatives to deal with these extreme hydrological features, this article analyzes the performance of offline and online operation, based on stochastic dynamic programming and deterministic model predictive control. Moreover, a quantitative assessment of the role of the hydro-meteorological information available in real time is provided. The case study considered is Marina Reservoir, a multipurpose reservoir located in the heart of Singapore. It is characterized by a large, highly urbanized catchment that produces significant discharges with a short time of concentration of approximately 1h. Results show that the online approach, by anticipating the inflow events, outperforms the offline one and provides a better compromise between floods control, pumps usage, and drinking water supply objectives.