Benton County Swimming Holes

2005 Water Quality Report: Methodology

Identifying and counting microinvertebrates


My research paper lists and explains the many many different ways to measure water quality, so please take the time to read it.The five different tests performed on the streams are listed and explained below. Pictures of the equipment are shown below, all of which are property of Philomath High School.

How many people understand the different components of water quality? Many would say that pollution plays a big part and they would be completely correct, but beyond that, answers are scarce. Very little is known to the general public about something that is so important to people’s daily lives. In fact, there are numerous things that can add or detract from water quality and there are also several ways to look at the health of a body of water.
Many people may know that water temperature is part of stream health or that the trees around the stream help to keep the stream healthy, but very few people know how the little bugs in the stream can tell a story about that water system. By looking at populations of macroinvertebrates in the stream one can instantly infer if the water is polluted, too warm, or has abnormal levels of dissolved oxygen. Although macroinvertebrates are able to give information about water quality, another simple way of looking at a stream is to look at the vegetation around it. A riparian zone has many functions that aid the stream and therefore can fairly accurately show what the water quality of that stream should be (Jeffries 57). There are many ways to measure stream water quality but three easy ways remain the best: the riparian zone, invertebrates, and electric meters all do a similar job but in different ways.

-Temperature (Listed in Celsius) Should be 17.8°C (64°F) for salmonid rearing. 12.8°C (55°F) for waters during periods of native salmonid spawning, egg incubation, and fry emergence from the egg and from the gravel. The thermometer on the D.O. meter is what is used.

-E. coli (Escherichia coli) As our E. coli auger and plates were long expired most of the summer there are only two days where E. coli was able to be measured accurately. E. coli is measured by the number of colonies per 1ml.

-Other notes are taken concerning human presence, weather, or anything else that is significant.


Hach D.O. 175 D.O. (Dissolved Oxygen) meter. The State of Oregon’s dissolved oxygen standards are as follows: for bodies of water containing cold-water aquatic life, the D.O. should not be less than 8.0 mg/L; for bodies of water with cool-water aquatic life, the D.O. should no be less than 6.5 mg/L; and for bodies of water with warm-water aquatic life, the D.O. should not be less than 5.5 mg/L.
OakTron pH Testr1 ph gauge. -pH (Scale from 0-14 with 7 being neutral). Measures how acidic or basic the stream is; streams should be from 6.5 to 8.5.
Hach 2100P Turbidimeter turbidity meter. Turbidity = "How many solids are suspended in the water." Excessive turbidity is detrimental to aquatic life.