Year | 1985 | 1988 | 1994 | 1997 | 1999 | 2002 | 2007 | 2011 |
6 month ET (mm) | 616 | 581 | 612 | 563 | 544 | 586 | 559 | 537 |
Extraction area (m2 × 106) | 1.16 | 1.33 | 2.28 | 2.30 | 2.39 | 2.68 | 3.19 | 3.11 |
Evaporation of bare soil (m3 × 106) | 0.72 | 0.78 | 1.40 | 1.30 | 1.30 | 1.57 | 1.78 | 1.67 |
Area with Vegetation (m2 × 106) | 15.2 | 15.0 | 14.1 | 14.0 | 13.9 | 13.7 | 13.2 | 13.2 |
6 month ET (grass) (m3 × 106) | 9.35 | 8.72 | 8.60 | 7.90 | 7.59 | 8.01 | 7.35 | 7.11 |
6 month ET (corn) (m3 × 106) | 7.20 | 6.71 | 6.63 | 6.09 | 5.84 | 6.16 | 5.66 | 5.47 |
Total ET (grass) (m3 × 106) | 10.1 | 9.49 | 10.0 | 9.20 | 8.89 | 9.58 | 9.13 | 8.78 |
Total ET (corn) (m3 × 106) | 7.92 | 7.49 | 8.02 | 7.38 | 7.14 | 7.73 | 7.44 | 7.14 |