Characterizing Aquatic Habitat for Steelhead Spawning at the Washington Closure Hanford

The EAS team conducted surveys in the 100 Area, 300 Area, and inter-areas of the Hanford Reach to determine if steelhead spawning habitat existed in these locations, according to accepted habitat suitability criteria, and document any steelhead spawning activity (fish or redds) at these sites. Characterization of the sites was important because steelhead spawning in these areas may be subject to man-induced risks, including chemical and/or radiological releases attributable to the Hanford Site and shoreline and riverbed modifications that cause siltation or affect habitat. Other activities that could present a risk to steelhead spawning include disturbance by biological and groundwater monitoring and treatment activities near the shoreline, ecological and cultural research and monitoring programs conducted on the river or shoreline, and alterations of the shoreline for public access purposes.

The field team found conditions entirely suitable for spawning at eight sites in survey locations along the Reach. Information from these surveys contributed to the process for assessing the potential risk to ESU-listed steelhead from Hanford Site operations.