Optimization of Urban Water Supply Planning for a Mid-sized City in the Yangtze River Delta

Rapid urbanization in China and many other countries brought renewed attention to urban water supply and demand management, as evidenced in many cities in the Yangtze River Delta (YRD) Region of China, the economic hub of the country. To optimize urban water supply to meet growing demand for many small and mid-sized cities in the YRD, we develop an optimization-based integrated urban water planning model, which consists of water demand growth prediction and water supply infrastructure capacity optimization. The demand growth prediction module projects into the future for the domestic, industrial and public water demands. The water supply capacity expansion module minimizes the total net present value of the water supply infrastructure construction and O&M costs over a long period of time, focusing on the size and timing of construction of new, or expansion of existing, water storage reservoirs. With the Haining City in Zhejiang Province as a case study, we predicted future urban water demand out to 2050, and provided optimal schedule and sizing of expanding the capacity of existing water supply reservoirs, which can satisfy growing water demand at the minimal level of economic cost. Given the representativeness of Haining as a mid-size city in the YRD, this study also provides useful insights for urban water planning of other cities in the region and beyond.