Land Management Agencies. Restoring Fish Passage through Culverts on ForestService and BLM Lands in Oregon and Washington Could Take Decades

摘要

The Bureau of Land Management, within the Department of the Interior, and theForest Service, within the U.S. Department of Agriculture, manage over 41 million acres of federal lands in Oregon and Washington, including 122,000 miles of roads that use culverts-pipes or arches made of concrete or metalto 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.When culvert openings are too high above the streams for fish to jump into or culverts are positioned at a grade too steep for fish to ascend, they pose barriers to fish attempting to access their natural rearing and spawning habitat. Passage through culverts is particularly important to anadromous fish, such as Coho and Chinook salmon (some of which are threatened or endangered), which are spawned in freshwater streams, but must travel to the ocean to mature, then travel back to the streams to spawn. In this context, you asked us to determine (1) the number of culverts that may impede fish passage on Bureau of Land Management and Forest Service lands in Oregon and Washington, (2) the factors affecting the agencies' ability to restore passage through culverts acting as barriers to fish (hereafter referred to as barrier culverts), and (3) the results of the agencies' efforts to restore fish passage.