Table 1: Land use/cover types and areal percentages within the study area.

Land use/cover type1998199920002001200220032004200520062007

Water (%)9.89.89.411.39.59.59.49.59.59.6
Urban (%)4.44.44.44.04.14.24.34.15.05.6
Forests (%)0.50.50.50.50.60.50.50.50.60.6
Grassland (%)34.534.533.031.629.030.529.732.627.631.0

Agricultural lands (%)
 Pasture14.014.014.014.014.014.014.014.013.913.9
 Barley4.34.31.63.70.52.21.31.00.60.1
 Corn0.50.51.83.91.92.40.25.34.713.5
 Soybeans1.01.04.75.011.621.317.714.519.914.6
 Other crops4.54.55.04.74.55.52.12.11.80.3
 Spring wheat8.28.212.66.815.03.87.26.15.63.6
 Fallow3.43.42.55.92.01.99.33.04.30.1
 Sunflowers10.710.76.34.33.10.00.13.01.70.9
 Sum46.546.548.448.252.651.051.949.152.647.0

Wetlands (%)4.34.34.34.34.34.34.34.34.86.2

Sum (%)100100100100100100100100100100

The total land area is about 260 km2.