Evaluating and mapping water supply and demand for sustainable urban ecosystem management in Shenzhen, China

Rapid urbanization has resulted in a shortage of regional water resources, causing an imbalance for water resources. With the implementation of ecological policies, regional water management has been developed. However, the relationship between supply and demand of water resources and spatial distribution remains unclear under current policies, which lead to a lag in decision making and irrationality in decision makers. Shenzhen, a highly urbanized city, was used as an example to discuss the balance of urban water resources and its driving force. Furthermore, practical guidance for ecosystem management is discussed. Results revealed that the supply and demand of water in Shenzhen were imbalanced in spatial distribution. The demand for water resources was greater than the supply at an urban scale, and the unsatisfied demand of basins accounted for 81.1% of the total area. The underlying factors that greatly affected water supply were construction land, forests, water bodies, and farmland. The population density, per capita green area, and industrial areas increased the demand for water resources. Ecological water and domestic water demand will become the main water demand. The government should actively explore and practice the mechanism of water resources development and protection, prioritize water conservation, improve the efficiency of water resource utilization and construct water-saving lifestyles. Additionally, discussion on the landscape greening configuration to reduce the ecological water demand is recommended. •The balance of water resources in the rapidly urbanized ecosystem under the regulation of ecological policy was mapped.•The supply and demand of water resources on the subwatershed scale was found to be imbalanced.•Ecological water and domestic water demand will become the main urban water resource demand.•Ecological management should use the basin as a unit and establish adaptive management of water resources.