Tp_MeasuringWaterQuality

How Do You Measure Water Quality?

A Forks Elementary School 3rd grader does a Dissolved Oxygen test with help from her high school
buddy.

The measurement of water quality is simple and can be done fairly inexpensively. Your expenses will be determined by what you want to do with your data and who is interested in your results. If your interest lies primarily in getting students out into the field to learn to take ownership of the watershed areas that impact their lives, monitoring at what is called a Level III is sufficient. You will obtain good data that will give you a good idea of what type of water quality you are dealing with. If you want the EPA to recognize your data as valid, your costs for equipment will be much higher as the protocols (the way tests must be run) are much more stringent. See materials to find out what kind of equipment and supplies we use in the field. We have chosen 9 different test parameters to determine water quality in the stream and rivers being tested, plus a macroinvertebrate analysis (see below)

Macroinvertebrates, or water bugs, are also an indicator of stream health and can be studied in a variety of ways. One simple and very effective method is the placement of leaf packs in the stream and their subsequent retrieval 2-3 weeks later. The leaf pack can be taken back to the classroom for analysis and sorting and will mainly yield the types of macros called shredders.. You may also use a simple kick net to gather up macros from the stream bed where they live and this technique will give you more of a variety of macros (gatherers, filterers, shredders, etc).. Students may also pick up rocks in riffle areas to see what is on the bottom side, using magnifiers to help them see what is there. Rocks should be replaced the way they were laying in the streambed when done.

Elementary school students can easily do macroinvertebrate surveys, dissolved oxygen, temperature, pH, and turbidity testing. If you seek help from older students in middle school or high school science classes, this will help you immensely and be a powerful experience for the students.

Middle and high school students can do macroinvertebrate surveys in more depth and any or all of the testing parameters listed below:

pH: Hydrogen ion (H⁺) and hydroxyl ion (OH^-) concentration levels.
D.O. (Dissolved Oxygen): amount of usable oxygen in the water
BOD (Biochemical Oxygen Demand): the amount of oxygen used up by bacteria in the decomposition of organic material
Nitrates: Concentration of nitrogen in the form of nitrates found in the water.
Phosphates: Concentration of PO₄ found in the water.
Turbidity: How clear or cloudy the water is.
Temperature Change: Taken at 2 different locations in the same body of water
Total Dissolved Solids: Measures the suspended and dissolved solid in the water.
Fecal Coliform: found in the intestines of humans and other warm blooded animals and are a good indicator of water quality.

See procedures for a complete description of the above parameters and what they measure.

By looking at the concentration levels of these water quality determiners, you are able to decide the level of water quality of the water body you are testing. If you test the same water over time, you are able to see what changes certain environmental and human impacts have on quality of water.

Updated August 2003

Contact: Sherry Schaaf, webmaster, sschaaf@esd114.wednet.edu