FIGURE 1. Average Annual Precipitation Based on 1981–2010 Normals National Oceanic and Atmospheric Administration. (NOAA). 2016. Average annual precipitation based on 1981–2010 normals. NOAA National Centers for Environmental Information.
FIGURE 2. Land Cover of the United States U.S. Geological Survey. 2014. National Gap Analysis Program (GAP), Land Cover Data Viewer. U.S. Department of Interior.
FIGURE 3. Figure 3. Dominant Soil Orders of the United States. USDA Natural Resources Conservation Service (NRCS). 1998. Dominant Soil Orders of the United States. USDA NRCS National Soil Survey Center: Lincoln, NE.