Finding Signs of Good Water Quality

Nets in hand, kids and adults spent an hour splashing through the stream at Oregon Ridge, turning over rocks, scooping up little critters in the water, and peering at the mud along the banks. Having fun while conducting a science project, the actual purpose was to collect samples to determine the water quality.

The participants were hunting for bugs, insects, fish, and frogs. But primarily, the group focused on macro-invertebrates such as crayfish, aquatic snails, and the larvae of aquatic insects. The types of samples found would be indicators of how healthy the stream is.

Stream-bottom macro-invertebrates are a link in the aquatic food chain. They survive by eating the leaves that fall in the water or algae growing on the stream bottom. In turn, they are eaten by larger animals such as fish, which in turn, are a source of food for birds, raccoons, water snakes, and people. The healthier the stream, the healthier the land around it.

Stream-bottom macro-invertebrates are good indicators of the water quality because they vary in how sensitive they are to polluted water. Some cannot survive in polluted water. Others can survive or even thrive in polluted water. In a healthy stream, the stream-bottom community will include a variety of pollution-sensitive macro-invertebrates. In an unhealthy stream, there may be only a few types of non-sensitve macro-invertebrates present.

The presence of frogs are also good indicators of water quality. Amphibians have highly permeable, exposed skin which easily absorbs toxic substances from the environment.  Frogs cannot live in polluted water.

Identifying the day’s catch:

In the recent sampling at Oregon Ridge, the collected and observed species indicate the water quality is “pretty good”. Pictures include crayfish, dragonfly larvae, a damselfly, and a frog.


Be sure to check the Oregon Ridge Nature Center calendar for other interesting and family-fun programs. Click here for the fall 2012 calendar.

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