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