Water Quality and Sampling Station

Water Quality and Sampling

Marilyn Moore

Malheur Co. Extension, OSU

Click on thumbnails to view an enlarged image.

At the Water Quality and Sampling Station, students learned about the factors used to determine whether the quality of water is good enough to sustain aquatic wildlife. Factors discussed and measured were water temperature, air temperature, water pH, and dissolved oxygen and carbon dioxide. As measured by the students in 2005, the water temperature ranged from 42 to 48 degrees as the air temperature increased from 65 degrees to 85 degrees. The water pH was 8, dissolved oxygen measured 12 ppm, and dissolved carbon dioxide was 6 ppm. Although phosphorus and nitrates are often of interest, these factors were not measured during the short sessions.

Marilyn pointed out that not every location is suitable for a particular species of fish. For example, trout like cool water that has a pH around 7 while a location like the pond at Beck Kiwanis Park in Ontario, OR has a pH of 8.5 to 9.

The amount of oxygen dissolved in water is an important factor and is necessary for fish and aquatic insects to live. Trout need 7 ppm dissolved oxygen to spawn. Dissolved oxygen can very dramatically by location, time of day, and time of year. For example, the water above the dam has 12 ppm dissolved oxygen while there is 16 ppm down in the ripples. Carbon dioxide dissolved in water is also an important factor and is necessary to sustain aquatic plant life. However; too much carbon dioxide is hard on fish, so there needs to be more oxygen than carbon dioxide in order for the fish to survive.

Students learned about aquatic insects and their life cycles. For example, did you know Buffalo gnats, damselflies, mayflies, dragonflies, and mosquitoes, all develop in the water? Students spent time sampling the river and identifying the insect nymphs that were present in the Owyhee Reservoir. Surprisingly in 2005, black fly nymphs were in the majority with very few other nymphs found: one mayfly, one caddis fly, and one dragonfly nymph out of the six sessions of students. This is surprising because, in 2003, the other nymphs were in the majority with very few black fly nymphs present.

To Water Quality Page

The Owyhee Watershed Council's educational activities are supported by the
Oregon Watershed Enhancement Board.

For further information please contact:
Jennifer Martin
Owyhee Watershed Coordinator
(541) 889-2588.

Owyhee Field Day Home Page