Finally, the waters surge upstream to the edge of the forest and gently lift trailing branches of rhododendron and cedar. The estuary is full. For a moment, the drama pauses. Then as the earth turns, the ocean's push becomes a pull, and the waters of the estuary recede. Before long, logs at the edge of the salt marsh are grounded on the mud, the eelgrass lies limp and flat, and tiny creatures are stranded in isolated pools of water warming in the sun.
Clam diggers move carefully across the muddy flats toward the edge of the winding channel.
But in a short time, the cycle will begin again. An estuary is defined as a semi-enclosed body of water, connected to the ocean, where salt water is measurably diluted with fresh water from the land. It is a zone of transition between the marine-dominated systems of the ocean and the upland river systems, a zone where the mix of the two yields one of the most biologically productive areas on Earth. The large number of estuaries on the Oregon coast belies the fact that Oregon's total estuarine acreage is relatively small. Most of the larger estuaries have been altered through dredging, filling or diking.