Friday, January 1, 2010

Intermittent Stream

During the winter, little water courses that have remained dry through the summer and fall begin to flow. Areas that haven’t had open water for half a year now have an abundance of small pools.

The water has filtered down through the soil on the wooded hillsides and appears as a narrow stream. The water is clear and clean. Winter birds prefer this water source over all others.

Storm runoff carries away leaves that have fallen into the stream channel. The water will continue to flow until mid spring and then things will again be dry. This type of seasonal flow defines an intermittent stream.

The small intermittent streams at Blue Jay Barrens are very nutrient poor and generally don’t support any algae or other plant life. Rain runoff removes sediment from the narrow channel so the substrate is generally rock. Several types of aquatic insects will lay their eggs in these streams in early spring.

There are some animal species that live exclusively in these tiny watercourses. A common one here is the flatworm know as the planarian. Planarians lay two types of eggs; one thin shelled that hatches soon after being laid and a second that is hard shelled and able to survive through the summer dry period. The eggs are hatching now, but the worms won’t be noticeable until late winter. Until then, I’ll just enjoy the sight of super clear water that flows in these streams.

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