At its lower end, the river may wander in many channels across its floodplain, providing a wealth of fish habitats in its wetlands, sloughs and oxbows. In these marshes and estuaries, ocean-bound salmon gorge on clouds of small crustaceans such as copepods and amphipods. All human activity in the watershed affects salmon habitat. Timber-cutting, for instance, may remove shade and large streamside logs that once fell periodically into the stream. Road construction and agriculture often cause erosion, which in turn fills the water with sediment that can clog spawning gravel.
Culverts can block fish passage and alter water flow.
Removing creek meanders or beaver dams and filling wetlands eliminates feeding areas and the slow-water areas so important for sheltering young coho and other salmon from the raging winter currents. Dams can slow the force of the river's flow preventing it from cleansing sediment from its bed and moving gravel downstream. Because human beings live in watersheds, we are part of the salmon's habitat. In many areas, small landowners, timber companies, fishermen, environmentalists, farmers, tribal members, agency representatives, and others are working together to restore watersheds and improve salmon habitat. Often called watershed, these coalitions are finding ways to put aside differences and pool resources to help the salmon.