National Water-Quality Assessment (NAWQA) Program
U.S. GEOLOGICAL SURVEY
Water-Resources Investigations Report 98-4222
Sacramento, California, 1999
Figure 3. Distribution of land use in (A) agricultural indicator basins, (B) urban indicator basins, and (C) integrator basins. Data are derived from U.S. Geological Survey (1990) and U.S. Depertment of Commerce (1995). Urban land-use data are derived from U.S. Geological Survey (1990), with revisions that are based on the 1990 population census (Hitt, 1994). Site codes are defined in table 1.