Class

Degree of reliability

Height (m)

Cover area

Area (KM2)

A

Very Good

800 - 1100

80.47

73.1725

B

Average

Under 800

67.49

30.1793

C

Weak

1100 - 1400

61.10

36.383

D

Inappropriate

More than 1400

40.0

68.4