Biotic index

Biotic Index (also called "Family Biotic Index") is a scale for showing the quality of an environment by indicating the types of organisms present in it. It is often used to assess the quality of water in rivers. It is measured from 1 to 10 and corresponds to the four basic water quality (Excellent, Good, Fair or Poor). The concept of the Biotic Index was developed by William M. Beck in an effort to provide a simple measurement of stream pollution and its effects on the biology of the stream