Stream Monitoring

The Cowpasture River Preservation Association monitors seven stations within the Cowpasture River watershed (see map below). Our dedicated and trained volunteers sample these stations for macrobenthic invertebrates every three months and bacteria and water chemistry monthly. Brief information on each sampling method is discussed below.


Macrobenthic invertebrate sampling: Many types of insects and other small animals live at least a part of their lives on or under the cobbly rocks in shallow areas of a stream or river.  Some are very sensitive to pollution and environmental stress, such as water that is too warm or has a lot of sediment in it. Others are somewhat tolerant, and some even quite tolerant of pollution and can live in very unclean waters.  Because of these differences in the animals’ tolerance, biologists have found that if they collect and count the numbers of different types of animals in a defined area of a stream, they can get an idea of how healthy, clean and/or stress-free a stream is over time.

Bacteria sampling: All animals, whether human, cow, horse, deer, rabbit, bird, fish or muskrat have to get rid of waste.  This waste contains natural bacteria that live in their intestines and help to process the food they eat. Natural processes in the soil and water usually absorb and use these bacteria, changing them into unharmful forms. But, when the levels of bacteria are greater than nature can handle, they can make people sick if taken in, for example, by mouth or through a skin cut. Monitoring the bacteria in waterways across the country is one of the first lines of defense against bacterial health threats from streams, rivers and other natural bodies of water, many of which are used for drinking water.

Water chemistry sampling: To gain the most complete overall picture of stream health, pH, conductivity, salinity, dissolved oxygen, nitrogen (nitrates) and phosphorus (phosphates) are monitored on a monthly basis within these seven stations. In addition, there are continuous data loggers for temperature at four locations around the watershed that are managed and downloaded regularly.

Important Links:

Map of Monitoring Sites in Virginia

VA SOS Online Training Resources

Izaak Walton League Water Resources