Evaluating Future Reservoir Evaporation Losses from CMIP6-Based Projections in the Conterminous United States
Abstract
Evaporation from the open water surface of reservoirs is a controlling factor for water loss, especially in arid/semi-arid regions. In the near future, the evaporation rate is expected to increase under a warming environment, exacerbating surface water stress. Therefore, it is essential to understand future long-term reservoir evaporation losses to better inform water resources management practices. In this study, evaporation rates and evaporation volumes for 678 major reservoirs in the Conterminous United States (CONUS) are evaluated over two future periodsthe near-term future (20202039), and the far-term future (20402059). The evaporation rates are calculated using the equilibrium temperature algorithm (Zhao and Gao, 2019), which integrates the heat storage effect. Future meteorological forcings (shortwave radiation, air temperature, vapor pressure deficit, and wind speed) are obtained from multi-ensemble downscaled Coupled Model Intercomparison Projects 6 (CMIP6) projections. The future reservoir areas are inferred by applying the projected runoff values (simulated by hydrological models) to the runoff-area relationships, which are established using historical runoff and remotely sensed area values. Results suggest that evaporation rates and evaporation losses will both increase, with much larger changes occurring in the far-term future. Compared to the reservoirs in the Eastern US, the change in rate of evaporation losses for those in the Western US will be more significant. At the seasonal scale, the increments of evaporation will be more severe in the fall and winter (than in the spring and summer). These findings can assist with the refinement of reservoir management considerations across various spatiotemporal scales.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.H41K..05Z