The Bureau of Land Management and the Forest Service manage more than 41 million acres of federal lands in Oregon and Washington, including 122,000 miles of roads that use culverts--pipes or arches that allow water to flow from one side of the road to the other. Many of the streams that pass through these culverts are essential habitat for fish and other aquatic species. More than 10,000 culverts exist on fish-bearing streams in Oregon and Washington, but the number that impede fish passage is unknown. Ongoing agency inventory and assessment efforts have identified nearly 2,600 barrier culverts, but agency officials estimate that more than twice that number may exist. Although the agencies recognize the importance of restoring fish passage, several factors inhibit their efforts. Most significantly, the agencies have not made enough money available to do all the necessary culvert work. In addition, the often lengthy process of obtaining federal and state environmental clearances and permits, as well as the short seasonal "window of opportunity" to do the work, affects the agencies' ability to restore fish passages quickly. Furthermore, the shortage of experienced engineering staff limits the number of projects that can be designed and completed. BLM and the Forest Service have completed 141 culvert projects to remove barriers and to open an estimated 171 miles of fish habitat from fiscal year 1998 through 2000. Neither agency, however, knows the extent to which culvert projects ultimately improve fish passage because they don't require systematic post-project monitoring to measure the outcomes of their efforts

The Bureau of Land Management and the Forest Service manage more than 41 million acres of federal lands in Oregon and Washington, including 122,000 miles of roads that use culverts--pipes or arches that allow water to flow from one side of the road to the other. Many of the streams that pass through these culverts are essential habitat for fish and other aquatic species. More than 10,000 culverts exist on fish-bearing streams in Oregon and Washington, but the number that impede fish passage is unknown. Ongoing agency inventory and assessment efforts have identified nearly 2,600 barrier culverts, but agency officials estimate that more than twice that number may exist. Although the agencies recognize the importance of restoring fish passage, several factors inhibit their efforts. Most significantly, the agencies have not made enough money available to do all the necessary culvert work. In addition, the often lengthy process of obtaining federal and state environmental clearances and permits, as well as the short seasonal "window of opportunity" to do the work, affects the agencies' ability to restore fish passages quickly. Furthermore, the shortage of experienced engineering staff limits the number of projects that can be designed and completed. BLM and the Forest Service have completed 141 culvert projects to remove barriers and to open an estimated 171 miles of fish habitat from fiscal year 1998 through 2000. Neither agency, however, knows the extent to which culvert projects ultimately improve fish passage because they don't require systematic post-project monitoring to measure the outcomes of their efforts.

GAO-02-136 Land Management Agencies: Restoring Fish Passage Through Culverts on Forest Service and BLM Lands in Oregon and Washington Could Take Decades

This technical paper reviews current information on the effectiveness of habitat rehabilitation techniques for inland fisheries, based on published evaluations of projects including studies on roads improvements and sediment reduction, riparian and floodplain rehabilitation, placement of habitat structures in lakes and streams, and the addition of nutrients to increase aquatic production. It also sets out information on planning, prioritising and monitoring rehabilitation projects.