Methow Restoration Council

Living With the Methow River

Monthly Activities and Learning Opportunities

April 2017

Water Quality

Water Quality

We humans do best with air that's about 20% oxygen, somewhere around 70° F, and reasonably clear (not choked with dust, smoke, or pollen). Just as we rely on certain conditions in the air that we live in, fish rely on certain conditions in the water that they live in. By studying water quality, biologists can determine whether a site meets the needs of fish.

Water quality is defined by the physical, chemical, and biological composition of the water. This includes temperature, oxygen concentration, pH, and turbidity. Water temperature is especially important because fish are cold-blooded, and their metabolisms function best at certain temperatures. Water that is too warm stresses fish and makes them more susceptible to disease and predation. If the water temperature doesn't meet their needs, fish will go somewhere else, seeking out warmer groundwater seeps in the winter or a cool deep pool in the summer.

Turbid (or cloudy) water, usually caused by sediments released by high flows and erosion, clogs fish gills and blocks sunlight from reaching underwater plants and algae. Sediment can also harm developing fish eggs, which rely on oxygen-rich water flowing through the clean gravel they reside in. Algal blooms (and the bacteria that break down dead plants and algae) can deplete oxygen levels to a point where fish cannot breathe, and may be forced to gulp air from above the water's surface. Oxygen levels are also partially determined by the temperature of the water; warm water can hold less dissolved oxygen than cold water can.

By measuring water quality, MRC partners can effectively monitor habitat conditions and plan habitat restoration projects to improve degraded conditions.

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2017 Calendar


This year’s MRC calendar connects to ADVENTURES, ACTIVITIES AND INFORMATION tailored to each month. If you haven't gotten your calendar yet, you can download an electronic version here.

Come back each month and find interactive activities, print outs, and suggested learning opportunities in our community.