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ABSTRACT:
Watershed water stress is caused by both water supply and demand which are both influenced by ecosystems and humans. This study developed a new water stress index that integrated both natural and anthropogenic effects on water stress. The overall goal was to improve the current water stress forecasting schemes to better inform water resource policy makers and the public. The Water Supply Stress Index (WaSSI) is the ratio of water demand to supply. Water supply is estimated by a monthly water balance model that accounts for climate and landuse/landcover, groundwater withdrawal, and return flow. Human water demand is estimated using historic water use data, as reported by the USGS or state water bureaus. Future supply and demand scenarios are modeled via changes in climate, land management, landuse/landcover, and population. We found that population growth will greatly increase water demand in metropolitan areas, but overall, population changes will have little impact on total water demand over the next 40 years. In contrast, changes in air temperature and precipitation will likely have significantly impacts on regional water availability in the coming decades. Forest management can reduce water stress temporaily through forest cutting, but it is not practical for water shoratge problems at the basin scale. We also found that groundwater reserves are critical to water shortages in regions that depend heavily on groundwater. We concluded that a comprehensive approach is needed to balance water supply and demand in order to face potential water shortages in the 21st century.
Watershed water stress is caused by both water supply and demand which are both influenced by ecosystems and humans. This study developed a new water stress index that integrated both natural and anthropogenic effects on water stress. The overall goal was to improve the current water stress forecasting schemes to better inform water resource policy makers and the public. The Water Supply Stress Index (WaSSI) is the ratio of water demand to supply. Water supply is estimated by a monthly water balance model that accounts for climate and landuse/landcover, groundwater withdrawal, and return flow. Human water demand is estimated using historic water use data, as reported by the USGS or state water bureaus. Future supply and demand scenarios are modeled via changes in climate, land management, landuse/landcover, and population. We found that population growth will greatly increase water demand in metropolitan areas, but overall, population changes will have little impact on total water demand over the next 40 years. In contrast, changes in air temperature and precipitation will likely have significantly impacts on regional water availability in the coming decades. Forest management can reduce water stress temporaily through forest cutting, but it is not practical for water shoratge problems at the basin scale. We also found that groundwater reserves are critical to water shortages in regions that depend heavily on groundwater. We concluded that a comprehensive approach is needed to balance water supply and demand in order to face potential water shortages in the 21st century.
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Project funded by Southern Global Change Program, Southern Research Station, USDA Forest Service For mroe information, contact Dr. Ge Sun Tel: 9195159498. |
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