Freshwater macroinvertebrates include aquatic insects, worms, and other invertebrates with limited mobility that live on or within the sediment or other substrates in streams, rivers, and lakes. These organisms spend all, or significant portions, of their lives immersed in water, therefore, aquatic insects are particularly susceptible to localized, short-term water quality changes.
The population size and population structure of these macroinvertebrates respond to the effects of acute and chronic pollution as well as changes in the physical environment; therefore, macroinvertebrates serve as continual monitors of environmental quality.
Cobb County has established 24 biological monitoring sites covering each major stream watershed within our borders. Sites are sampled once per year and results are evaluated along with historical biological, chemical and habitat data from the same location in order to detect long term changes in stream health.
Cobb County macroinvertebrate sampling began with a qualitative approach in the 1990’s and developed over time into the quantitative analytical program it is today. Adherence to strict protocols allows our local data to be compared with results from across the state of Georgia.