Methodology for including reservoir regulation in water scarcity evaluation

Abstract

Water scarcity evaluation is essential for the sustainable development of water resources. Reservoirs can regulate water temporally and spatially to meet human needs and mitigate water scarcity. No approach has considered reservoir regulation in water scarcity evaluation. We propose a simulation model of a water resource system that explicitly incorporates reservoir regulation functions into water scarcity evaluation. The model is validated using data from the Haihe River basin, northern China, using an improved water scarcity indicator to describe the severity of water scarcity. The results show that, from 2000 to 2005, the annual Water Stress Index of the Haihe River basin was 1.02 without considering reservoir regulation, and 0.92 considering reservoir regulation. That is, incorporating reservoir water availability into the evaluation reduces the estimated water scarcity. Water scarcity was overestimated temporally and spatially when the effect of reservoir regulation was not accounted for. Our results show that reservoirs can have a significant influence on water scarcity evaluation, especially in smaller and subdivided units. We recommend consideration of the role of reservoirs when evaluating water scarcity to better inform water resource management decisions.