Ecological Condition of Wadeable Streams of the Interior Columbia River Basin
Herger, L.G., G.A. Hayslip, and P.T. Leinenbach.
2007. U.S. Environmental Protection Agency, Region 10, Seattle, Washington.
The Environmental Monitoring and Assessment Program (EMAP) was developed by EPA to assess the condition of the nation's ecological resources. EMAP employs a statistical design that makes it possible to describe the proportion of the resource in good, fair or poor condition relative to reference condition. In 2000, the EMAP began a five-year effort to monitor and assess the ecological condition of rivers and streams across the West. This report uses a subset of the data from this large project and data from other EMAP projects to assess the ecological condition of the wadeable streams of the Interior Columbia River basin. Approximately 75,000 km of the 109,000 km of wadeable streams of the Basin were assessed for most indicators. In general, most streams of the basin are in fair or good condition based on the results of the metrics that could be analyzed. Primary stressors in terms of both extent and risk to biota are excess fine sediment, riparian disturbance from grazing/crops, sulfate, and phosphorous levels.