The Thompson Falls Dam fish ladder, the first full-height structure of its kind in the United States built specifically for the bull trout, features 48 steps rising 48 feet over the existing dam structure on the Clark Fork River, providing hundreds of miles of unhindered access to the river and its tributaries.

PORTLAND, ORE. — GEI Consultants, Inc., a geotechnical,environmental, water resources, and ecological science and engineering firm, announced that the new upstream fish ladder, located at the Thompson Falls Hydroelectric Plant in Thompson Falls, Mont., is ready to pass fish. The $7.5 million precedent-setting fish ladder is the first full-height fish passage ladder in the United States built specifically for the bull trout, a threatened species.

GEI Consultants was engaged by PPL Montana to provide ecological and engineering services for the project, designed to provide rare species of trout and other fish varieties unhindered access to hundreds of miles of the upstream Clark Fork River and its tributaries. The fishway is part of PPL Montana’s federal operating license in compliance with the Endangered Species Act. The project was developed as a collaborative effort through an inter-agency, multi-disciplinary team composed of PPL Montana; the U.S. Fish and Wildlife Service; Montana Fish, Wildlife and Parks; Montana Department of Environmental Quality; the Federal Energy Regulatory Commission; the Confederated Salish and Kootenai Tribes; GEI Consultants; and others. In addition to engineering services, GEI provided technical assistance to the team by performing fish behavior studies in the tailrace, assessing the feasibility of a range of alternatives, designing the facility, and providing design assistance during construction.

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