The Lemhi watershed in eastern Idaho historically was an important and productive watershed for salmon, steelhead, and bull trout; but these species have declined dramatically in this watershed and throughout the Upper Salmon River basin. Plaintiff Western Watersheds Project brings this case to challenge Defendants’ violations of the Endangered Species Act (“ESA”) in not properly managing for and recovering these species of fish in the Lemhi drainage.
The Lemhi River in central/eastern Idaho drains the Lemhi, Bitterroot and other mountains; and enters the Salmon River just north of the town of Salmon, Idaho. The Lemhi watershed provides habitat for three species of threatened fish: Snake River spring/summer Chinook salmon, Snake River steelhead, and Upper Columbia River bull trout. Endangered sockeye salmon migrate past the mouth of the Lemhi River in the Salmon River on their way between their spawning grounds in headwater lakes of the Salmon River and the ocean.
These fish require clean, cold water to survive and reproduce. Water that has elevated levels of sediment, temperature, or other pollutants impairs the survival of the fish by hindering their biological functions, and also impairs reproduction by covering spawning gravels where the fish lay eggs with sediment that suffocates the eggs and young fry that emerge. The fish also require cover in the form of undercut banks and overhanging vegetation, large woody debris, and deep pools that allow them to hide from predators and rest outside of the current.
Livestock grazing is a threat to ESA listed fishes
Authorization of livestock grazing on federal land is a federal action that requires ESA consultation because it poses significant adverse effects to listed fish. Livestock prefer grazing in riparian areas because of the water, shade, and rich vegetation present there. This heavy use causes overgrazing of riparian vegetation as well as trampling and shearing of streambanks, which in turn reduces stream shading, increases sediment input into streams, and alters the floodplain and stream channel. These effects lead to warmer waters with higher levels of sediment and fewer protected areas for fish in the form of undercut banks and deep pools. Warmer water temperatures and sediment affect not only the streams in the immediate vicinity of the livestock but also downstream fish habitat.
Livestock also walk in the streams, trampling spawning gravels and destroying redds of salmon, steelhead, or bull trout, as well as contributing further sedimentation and pollution with their excretions.
Grazing in the uplands affects fish habitat too. Livestock trample soils and destroy biological soil crusts, causing soil erosion that leads to more overland transport of sediment that is deposited in streams and degrades fish habitat. Cattle also compact soil, which reduces water infiltration and lowers the water table. In order to remove cattle away from riparian areas, the agencies often “develop” upland seeps and springs by piping water from these wetland areas into troughs for cattle to drink. But such water developments remove water from these natural sources, altering the hydrology of the watershed and reducing groundwater that contributes to streamflows later in the summer.