A stream is the expression of its watershed. Whatever happens on the land will affect the waters. For the creatures that dwell in streams, the requirements for life must be present... provided at the whim of nature or taken away at the whim of humankind.

Streams are dynamic, constantly changing, shaped by the interaction between the flowing water and the surrounding landscape. Channels shift in their valleys; bed and banks erode, providing the gravels that form spawning beds for salmon and trout and crannies for aquatic insects.

Pools form where flows scour the streambed or plunge over and around fallen trees. These downed logs and trunks from the streamside are critical to the structure and function of Northwest streams.

All of these elements, interacting in complex ways, form the habitats of our streams and rivers. Habitats that are rich with life. Salmon are the essence of life in Northwest streams, a measure of the condition of the stream and its watershed. As the land goes, so goes the stream; and so also, the salmon.

The work of streams

Streams carry water from the land to rivers, to lakes, and eventually to the ocean. As this work is done, habitats are made and unmade by the flowing water. Streamdwellers are adapted to this constant current; their shapes, their ways of feeding and reproducing, their dwelling places, all formed by the endless rush of water.

As the stream influences the land, so the land influences the stream in profound ways. The vegetation that lines the stream, called the riparian zone, is of particular importance.This canopy of shrubs and trees provides cooling shade as well as falling leaves and insects that are food for other aquatic insects, crayfish, and salmon. Branches and trunks of fallen trees slow the water, form eddies and pools, trap sediment and detritus, and shelter salmon and trout. Roots anchor streambanks, holding the soil. Large roots stretch to the stream, providing shelter. Loss of this vegetation is disastrous for a stream and especially for salmon.

In the Northwest, salmon swim at the center of the stream ecosystem, linking the land with the sea. Born and reared in the clear, cold waters of our rivers and streams, most juvenile salmon species feed on aquatic insects - mayflies, stoneflies, caddisflies, and others. These insects feed upon the detritus of decaying leaves, wood, and other stream life. The decayed carcasses of adult salmon returned from the ocean to spawn and die are transformed into nutrients for the stream and food for their own offspring. It is a web of ecological elegance, and is the foundation of a great Northwest mythology centuries old.

Streams and people

The streams of King County and Puget Sound are a legacy of the glacial past. As the continental glaciers receded some 11,000 years ago, our streams began to form the valleys and floodplains we see today. Salmon began to crowd the streams perhaps 4,000 - 5,000 years ago and quickly came to dominate the lives and myths of the native peoples.

In the last 100 years, we have managed to reduce these once-great salmon runs. Through channelization, flood control measures, forestry, agriculture, road building, and other human activities, we have reduced the habitability of our streams and rivers for the creatures that dwell there and, very often, for ourselves. Our streams and rivers are irreplaceable resources. If our best efforts fail to protect our streams, the myths will be all that remains.

Stream words:

• Aquatic: Pertaining to water, commonly fresh water, or dwelling in fresh water.
• Detritus: Dead and decaying plant and animal matter. Forms a large portion of the food base in streams.
• Habitat: The living place where an organism feeds, reproduces, rests, hides, etc.
• Large woody debris: Trunks and large branches of trees that have fallen into a stream.
• Pool: A deep, scoured portion of stream where water flows slowly. Feeding and resting place for salmon.
• Riffle: A shallow rapids where water flows swiftly over gravel. Home to aquatic insects.
• Riparian zone: The area of vegetation adjacent to a body of water that influences (and is influenced by) the water.
• Salmonid: A species of the family salmonidae - the salmons, trouts, chars, and whitefishes.