(1) Description:

(a) Freshwater habitats of special concern provide essential functions important in the developmental life histories of twenty-two priority fish species. Priority fish species include species that are listed under state and federal endangered species laws, and species of recreational, commercial, or tribal importance.

(b) The presence of freshwater habitats of special concern or adjacent areas with similar characteristics may restrict project type, design, location, and timing. These restrictions also may benefit other fish species that use these habitats. The department may determine the location of such habitats by a site visit, and/or by considering maps, publications, and other available information.

(2) Fish life concerns:

(a) All fish and shellfish have special habitat requirements related to water quantity and quality (including temperature) and to the physical features of the stream or body of water in which they live. For example, salmon and steelhead spawn and live for a time in a stream before going to the ocean. They require an ample supply of clean, cool, well-oxygenated water. Adults need clean gravel in which to spawn and juvenile fish require instream cover such as tree parts, boulders, or overhanging banks in which to hide from predators. Vegetated stream banks shade the water from the warming effects of the sun. Insects drop off overhanging vegetation and provide food. When juvenile salmon or steelhead enter saltwater, their habitat requirements change. During this critical transition period, they must have shallow, nearshore waters where they can migrate, school, feed, and seek protection from larger fish. Each species of fish and shellfish has similar, yet unique requirements. They have become adapted to and require these natural conditions as a result of the ten thousand years of evolution since the last ice age. The degradation of any one of the elements of their required habitat results in reduced numbers of fish and shellfish.

(b) Construction activity in or near the water has the potential to kill fish or shellfish directly. More importantly, this activity can also alter the habitat that fish and shellfish require. Direct damage or loss of habitat results in direct loss of fish and shellfish production. Direct killing of fish or shellfish is usually a one-time loss. Damaged habitat, however, can continue to cause lost production of fish and shellfish for as long as the habitat remains altered.

(3) Freshwater habitats of special concern:

(a) The following habitats serve essential functions in the developmental life histories of twenty-two priority fish species:

(i) Spawning habitat;

(ii) Rearing habitat;

(iii) Migration corridors;

(iv) Cover and shelter provided by large woody debris, live tree roots, deep pools, shallow water, undercut banks, overhanging vegetation, turbulence, and large interstitial areas in cobble or boulder substrate;

(v) Off-channel habitat including wall-based channels, flood swales, side channels, and flood plain spring channels;

(vi) Native aquatic vegetation beds; and

(vii) Native riparian vegetation zones.

(b) The following are important geomorphic processes that form and maintain freshwater habitats of special concern:

(i) Woody material sources, delivery, and transport; and

(ii) Sediment sources, delivery, and transport.

(c) A person may request information from the department about the location of priority fish species and freshwater habitats of special concern. Information about priority fish species is also available on the department's website.