Study Looks Beyond Precipitation to Project Future Water Availability


Maps of projected runoff changes in the 2030sHistoric precipitation data have typically been scientists' number one source of information used in research to project future water runoff. “But things are changing and getting more complicated,” says Ge Sun, an Eastern Threat Center research hydrologist and co-author of a study that considered the role of other climate drivers in determining runoff and, therefore, the water available for humans and ecosystems. A research team led by Kai Duan, formerly a post-doctoral researcher with the Center who now conducts research with the Coweeta Hydrologic Laboratory, used the Water Supply Stress Index (WaSSI) model to examine the influence of several climate variables. The model included temperature, solar radiation, wind speed, and specific humidity, in addition to precipitation, and projected runoff changes across the United States and within regional areas for the near and far future (2030s and 2080s, respectively) in comparison to the time period between 1970 and 1990. Findings revealed that areas in the central and southern United States could see decreased runoff primarily due to rising temperatures, which increase plants' use of water through evapotranspiration. Rising humidity in the East could offset some of the increases in evapotranspiration to stabilize runoff and water availability. Alternatively, runoff could increase in other areas of the country where precipitation is the dominant climate influence. Study results can help guide strategies for water conservation and other location-specific water management needs. Read more in CompassLive...

Pictured: Maps from a model scenario show (left) projected percent change in annual runoff in the 2030s (decreases in reds, increases in greens) and (right) the relative importance of precipitation and temperature (blue and red, repectively) in these changes.


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