| Figure 2. Researchers use a variety of inputs to build hydrologic models to provide streamflow forecasts for decision makers. Inputs include (clockwise from bottom left): precipitation forecasts to calculate future watershed inputs; snow-covered area maps to estimate water stored in the snowpack; a digital elevation model to indicate topography; ground data such as air temperature and snow water equivalent at SNOTEL sites; and land cover information such as vegetation and soil type to estimate rates at which water evaporates and is absorbed. These data are combined in a computer model with satellite imagery, and after mathematical analysis, researchers produce snow water equivalent estimates that reflect variations over thousands of miles of mountainous terrain. Estimates then inform water resource managers and water users about potential water supplies during the coming spring and summer seasons. |
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