Good water quality in a watershed is a function of good physical, chemical, and biological properties which can sustain all uses; it is critical to sustain life. Human activities can definitely affect water quality in watersheds.

Water quality is defined as the chemical, physical, and biological characteristics of water with respect to its suitability for a particular use. The quality of water in a river is a reflection of land uses and natural factors found in its watershed. Understanding a river’s water quality and quantity involves investigating the condition of the watershed. If the watershed is polluted, the river will likely be polluted.

Physical parameters defining water quality include color, odor, temperature, solids (residues), turbidity, oil, and grease. Inorganic chemical parameters include salinity, hardness, pH, acidity, alkalinity, iron, manganese, chlorides, sulfates, sulfides, heavy metals (mercury, lead, chromium, copper, and zinc), nitrogen (organic, ammonia, nitrite, and nitrate), and phosphorus. Biological parameters include coliforms, fecal coliforms, specific pathogens, viruses, and diversity indexes.

Water quality plays an important role in the health, abundance, and diversity of aquatic life. Excessive amounts of some constituents, algae, nutrients, and suspended particles, or the lack of others, including dissolved oxygen, can result in imbalances in water chemistry. Episodic or prolonged imbalances can potentially degrade aquatic life enough to harm the food chain, our fishing and recreational industries, and even the air we breathe.

The increasing impacts of human activities on aquatic resources have spurred a renewed sense of stewardship. The Volunteer Water Quality Monitoring Program of Missouri STREAM TEAMs is valuable to government monitoring programs. Volunteers trained and equipped to monitor various physical, chemical, and biological factors are providing high quality data. Trained citizens groups are collecting credible data and are making significant contributions to our knowledge of water quality.

Successful citizen water quality programs include: a basic understanding of how physical, chemical, and biological test methods work, which helps avoid confusion and errors in monitoring. An understanding of significant levels of various water quality parameters puts in perspective the health of a stream. Interpreting results from water quality monitoring is important to formulate plans for improvement of a stream’s health.

Water pollution problems are defined as the overabundance of one or more natural or human made substances in water. These are divided into two major types:

1. Point source pollution is traced to a single source, like a pipe, culvert, or ditch. Most people can identify point source pollution problems, including discharges from pipes from manufacturing plants, or discharges of sewage.
   
2. Nonpoint source pollution is a more subtle water quality problem, originating from a much wider area. It often depends on rain or wind to deliver the pollutant to the stream. Soil from eroded fields, acid runoff from old strip mine areas, and runoff from livestock feedlots are examples of nonpoint sources.

A visual inspection of a stream is the first step in determining water quality problems. However, not all water quality problems are detected this way. Color, smell, and the presence of any stream bed coating are indicators of problems.

BIOLOGICAL TESTING

Biological testing is an important means of measuring the water quality of a stream. In biological testing, water quality is evaluated by the presence or absence of macroinvertebrate populations, which indicate the overall health of the ecosystem. Macroinvertebrates are invertebrates, large enough to be seen with the naked eye, that inhabit rivers, streams, lakes, and ponds. These animals are benthic (bottom dwellers) and are associated with bottom substrates such as rocks, logs, sediment, debris, and submerged plants. Macroinvertebrates typically include immature forms of aquatic insects, aquatic worms, crustaceans, and mollusks. As noted on the Stream Insects and Crustaceans card provided in a previous lesson, the macroinvertebrates are arranged into three categories or taxa according to their sensitivity to pollution. The three taxa are sensitive, somewhat sensitive, and tolerant. Additionally, an important factor in giving a stream a water quality rating is the diversity of the populations found in the stream system. Healthy and stable ecosystems are characterized by greater diversity of organisms. Pollution tends to reduce species diversity by eliminating organisms that are sensitive to organic and other pollutants entering their environment. The Missouri Stream Team protocol is used to sample macroinvertebrates and rate the water quality in your adopted stream. This method involves disturbing a 3' x 3' riffle (shallow, fast moving area of the stream where water tumbles over rocks) to collect macroinvertebrates living in the substrate. To dislodge the organisms, rocks are rubbed clean and the streambed is disrupted by kicking and shuffling as deep as six inches. The organisms are caught in a kick net or seine, and the types and numbers of macroinvertebrates are sorted and counted. This data is used to calculate a water quality index value. Different times of the year will produce different results. Therefore, it is important to monitor during the four seasons at the very least.

Evaluating water quality requires experience and training. Water quality seminars are available for those wanting to learn more about monitoring. Call 1-800-ST1-1989 for more information or visit the Stream Team website at www.mostreamteam.org and check out the Water Quality Monitoring workshop schedule for a workshop near you. The introductory class covers the macroinvertebrate monitoring techniques.