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Indicators of Water Quality

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There are numerous indicators of water quality. Sometimes the land use can provide clues to stream water quality. A wooded stream would likely have better water quality than a channelized stream flowing through an urban environment. Color can also be an indicator. In areas where there has been extensive mining, rust colored water can be a sign of poor water quality. Luckily that is not a problem in Caesar Creek watershed. More likely color indicators of water quality would be a green paint like sheen at the surface of the water, or water with a very green tint and poor visibility. Common tools to determine water clarity include the Secchi disk or a turbidity tube. Here is an example of a homemade secchi disk. The disk is lowered into the water until it is no longer visible then the distance from the disk to the water surface is recorded.

You can look at the organisms living in streams and lakes to gauge water quality. Fish populations are used as biological indicators. Aquatic biologist use specialized backpack units for stream sampling. The procedure is very effective but requires specialized training, special licenses and safety precautions to do it safely. Benthic macroinvertebrates are easy to sample and provide a good indicator of water quality conditions.



Benthic ("bottom dwelling") macro invertebrates are small aquatic animals and aquatic larval stage insects. Some examples include dragonfly and mayfly larvae, clams, snails and beetles. They spend all or most of their lives in water. They are easily to collect, can be seen without a microscope and differ in their tolerance to pollution. Unlike fish, macroinvertebrates have limited mobility. The abundance and variety of benthic macro invertebrates in a water body gives an indication of the biological condition of the stream. Water bodies that are in healthy biological condition typically support a wide variety and more numerous populations of macroinvertebrates. Samples yielding only pollution - tolerant species or very little diversity indicate a less healthy waterway.

One volunteer program that uses benthic macroinvertebrates as an indication of water quality is the ODNR Stream Quality Monitoring (SQM) program. Rivers and streams in the Ohio Scenic Rivers program are monitored regularly to ensure that the water habitat quality remains high.

Here is a link to the ODNR Stream Quality Monitoring page.

Last updated Feb 16, 2025