Oregon Watersheds

Cities in western Oregon have a history of providing safe drinking water to their residents. In February 1996, however, during the region's worst storm in decades, the water quality in rivers and streams was severely degraded as the amount of fine sediment suspended in the water--known as turbidity--increased dramatically. After the storm, Salem, Oregon, whose municipal water treatment system had been shut down for a week, and environmental groups raised concerns about the extent to which timber harvests and forest roads on lands managed by the Forest Service and the Bureau of Land Management contributed to the increased turbidity. This report describes (1) the human activities that may have contributed to the high turbidity levels during and after the February 1996 storm and (2) the efforts under way by federal, state, local, and private land managers and owners, as well as the affected cities, to ensure safe drinking water during future storms.

GAO noted that: (1) human activities--timber harvests and related roads as well as agricultural, industrial, urban, and residential development--can contribute to elevated sediment levels during large storms; (2) these activities result in soil that is compacted, paved, covered, or cleared of most vegetation; (3) rain falling on compacted or cleared soil can run off into streams, carrying with it eroded topsoil; (4) in addition, rain falling on roofs, paved roads and parking lots, and other covered surfaces does not penetrate into the ground, thereby increasing the runoff that moves across barren or disturbed soil and eroding topsoil; (5) this sediment can then be transported into streams; (6) the sediment from human activities in a municipal watershed, combined with the accelerated erosion that naturally occurs during storms, can shut down a municipality's water treatment system, as occurred in Salem in February 1996; (7) ongoing federal and nonfederal efforts have made significant progress in: (a) mitigating the impact of human activities on water quality and ensuring safe drinking water to cities in the Willamette and Lower Columbia river basins; and (b) involving more key landowners and other stakeholders in discussing, understanding, and addressing watershed issues and concerns and in implementing restoration plans; and (8) nevertheless, some key landowners have not been included in coordination efforts, and many efforts could benefit from a better understanding of, and data on, the condition of the watersheds.

Recommendations

Our recommendations from this work are listed below with a Contact for more information. Status will change from "In process" to "Open," "Closed - implemented," or "Closed - not implemented" based on our follow up work.

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