Categorization

Index Value

Water Quality

Excellent

95 - 100

•     Virtual absence of threat or impairment.

•     Conditions very close to natural or pristine levels.

Good

80 - 94

•     Minor degree of threat or impairment.

•     Conditions rarely depart from natural or desirable levels.

Fair

65 - 79

•     Occasionally threated or impaired.

•     Conditions sometimes depart from natural or desirable levels.

Marginal

45 - 64

•     Frequently threatened or impaired.

•     Conditions often depart from natural or desirable levels.

Poor

0 - 44

•     Almost always threatened or impaired.

•     Conditions usually depart from natural or desirable levels.