Good water quality is fundamental for river health, as it sustains ecological processes that support native fish populations, vegetation, wetlands, and other wildlife. We also depend on clean water for drinking, irrigating crops, fishing and recreation, and to meet cultural and spiritual needs.
The water quality index includes eight water quality variables: temperature, dissolved oxygen, biochemical oxygen demand, pH, ammonia+nitrate nitrogen, total phosphorus, total solids, and Escherichia coli (E. coli) bacteria.