Improving water ecosystem sustainability of urban water system by management strategies optimization

Water management strategies play an important role in water shortage alleviation. This study evaluates the cost and water ecosystem benefit of 14 water management strategies in Beijing in the future scenarios for 2020 and 2035. In addition, optimal implements of abatement strategies are obtained within the context of legislated targets, with the consideration of interaction among strategies. The result shows that Beijing can meet its commitments for total water use and pollution control by the water management strategies implementation in both 2020 and 2035. For 14 water management strategies analyzed in this study, 5 options with negative abatement cost value achieve 12.2-24.1% of the total water ecosystem benefit in 2020 and 2035. Wastewater reclamation is the most efficient strategy in water ecosystem impact (WEI) reduction, which contributes 38.4% of the total WEI reduction with an abatement cost of 1.6 Yuan/m³ H₂O -eq. However, the sequence of optimal strategy implementation rate is not in accordance with the abatement cost of the strategies. The most cost-effective option is the water-efficient shower head, while the highest implementation rate is found for promotion of production technologies. A comparison between water management optimization with and without the consideration of interactions among strategies shows that taking the interaction among strategies into account imposes almost no influence on the total WEI reduction. But it has impacts on optimal implementation rate of each water management option and the cost estimation (+10.8%) of water management implementation. Such a systematic analysis of water management strategies provides general recommendations on sustainable water resource management in water scarce regions.