Scappoose Bay Watershed Assessment, 2000

Scappoose Bay Watershed Assessment, 2000

Document is available at the Council office.

Completed in 2000, this report provids a broad foundation for effective restoration of native fish species and their aquatic habitat in the Scappoose Bay Watershed. The report has been used extensively to understand and prioritize key issues in the watershed.

This assessment presents the existing baseline information on watershed conditions (based on available reports and data) and oral history interviews. A Geographic Information System (GIS) was built to display, analyze and store much of the data. Habitat factors for the decline of salmonids are compared, and major protection and restoration opportunities are identified and prioritized. This Phase I assessment does not generally provide the detailed field reconnaissance and comprehensive field studies that are necessary for proceeding with specific protection and restoration projects. Rather, this assessment lays out the groundwork for a second phase of assessment that bridges the gap between identifying major areas for action and conducting specific projects.

Historially, the Scappoose Bay Watershed supported four of six salmonid species found in the Pacific Northwest, including Chinook, Coho, steelhead, and cutthroat trout. It contained a broad diversity of habitats, ranging from small, steep mountain streams to broad, low-gradient stream valleys to the lowland floodplain of the Columbia River estuary.

Over the past 150 years, the watershed has been impacted by a broad range of uses: agriculture, forestry, surface mining, and residential and industrial development. The dramatic decline in all species of salmonids in the watershed is not due to one or even several independent habitat-impacting activities, but rather to a complex interplay of activities that have degraded specific habitats used at particular times in the life histories of the fish. Included in this complex scenario is the effect of introduced hatchery fish and fishery management policies, as well as the shift to poor ocean conditions along the Oregon and Washington coasts throughout the 1980’s.