There are many ways to monitor the health of a waterway.  Some are fairly simple, just looking at the physical features such as temperature, how clear the water is, whether logs and other items are jamming up the flow, trash, and erosion of the banks.  Other methods involve taking a sample of water and analyzing it for things like acidity, the amount of oxygen, and the chemicals and bacteria that are in it.  These methods can require sending a water sample to a scientific laboratory.  Yet another method is one in which the animals that live in the waterway are examined for their numbers and/or their health.  This would include studies of the fish and mammals, often made by biologists from state and federal agencies.  But, it might also involve some less obvious animals, the insects and other "critters" that live under the rocks in a stream or river.  These are called "benthic macroinvertebrates" and include early development forms of many insects that we are familiar with, such as may flies, dragon flies, black flies, and water beetles.  At the present time, CRPA volunteers conduct both bacterial and benthic macroinvertebrate monitoring along the Cowpasture as well as one of its main tributaries, the Bullpasture River.