The Criteria for Calculating Water Quality Index (WQI) is illustrated below –
a) WQI is a single defining criteria as Satisfactory or Unsatisfactory.
b) Considered 4(four) water quality parameters (viz. Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Faecal Coliform & Total Coliform counts) for Water Quality Index (WQI) for which Water Quality Criteria is prescribed.
c) Based on the measured ambient concentrations and corresponding criteria, water quality will be defined as satisfactory or unsatisfactory.
d) The criteria for each parameter is as follows -
e) Even one single parameter from these four parameters exceeding the criteria values will considered as Unsatisfactory.
The month wise Water Quality Index of River water at Different Locations in the State of Assam are mentioned below: