Impacts of dams and reservoirs on local climate change: a global perspective

As a primary artificial project in a river basin, the role of large dams and related reservoirs in mitigating the hydrological and meteorological extremes has been widely recognized. Moreover, construction of additional large dams is considered as one of the best available options to meet future increases in water, food, and energy demands, although this may drastically affect the surrounding natural environment. However, the issue about the degree of such effects is still unclear, although the interactive impacts of dams and related reservoirs on the changes in meteorological variables are of great scientific importance. Therefore, this study aims to explore the impacts of reservoir characteristic factors (RCFs) on local climate change near the reservoir through examining the correlations between the RCFs of selected dams and related reservoirs and meteorological variables all over the world. The major findings are: (a) the correlations of the RCFs with evaporation are the opposite of those with precipitation; (b) dams and related reservoirs can have completely opposite (weakening or enhancing) effects on different meteorological variables; and (c) the RCFs outperform the geographical factors in terms of the impact on precipitation, whereas the variation of evaporation is more sensitive to geographical factors. Overall, the outcomes of this study will be useful for policymakers to have a more informed understanding of local climate change affected by large dams and related reservoirs in the future.