Surveying stream macroinvertebrates provides information about the health of your stream. Many stream-dwelling organisms are sensitive to changes in water quality.
Their presence or absence can serve as an indicator of environmental conditions.
Creek Freaks collect aquatic insects and crustaceans with a net, then sort and identify the bugs using Izaak Walton League Save Our Streams field guides or other resources. Bugs are divided into three categories based on their level of pollution tolerance - sensitive, somewhat sensitive, and tolerant.
The diversity of bugs, not the number individuals, is used to determine water quality. The number of types of bugs found in the pollution sensitive category is multiplied by 3; the number of types of bugs found in the somewhat sensitive category is multiplied by 2, and the number of types found in the pollution tolerant category is multiplied by 1. This results in a numeric score of 1 to 26. These scores are then translated into descriptive scores as follows:
Poor = <11
Fair = 11-16
Good = 17-22
Excellent = >22