WATER QUALITY INDEX

WQI Tests:

  • Dissolved Oxygen
  • Fecal Coliform- bacteria primarily found in the intestines of humans and animals
  • pH- measure of acidity or bascitiy in the water
  • Biological Oxygen Demand (BOD)
  • Temperature
  • Total Phosphate
  • Nitrates
  • Turbidity
  • Total Solids- amount of sediment in the water

Sample WQI Curve Chart

For example, a dissolved oxygen curve chart is shown above. If the raw data number found was found. First, find 40 on the x-axis and then move straight up to the curve chart line and then read the Q-value which is plotted on the y-axis. In this case, the Q-value would be a 30. Then the Q value is placed on the WQI form shown below. The Q-value is then multiplied by the weighing factor in the next column giving a total. All of the totals are added together giving an Overall Water Quality Rating.


Overall Water Quality Index ______________