The decision to remove the Elwha and Glines Canyon dams on the Elwha River, Washington was preceded by the collection of substantial amounts of biological and physical data. Studies were conducted to identify existing water quality within the reservoirs and river, fish populations and habitat availability, fish passage mortality through the dams and reservoirs, effects of the hydro-power projects on wildlife habitat, and economics. Although this information was generally specific to the federal hydropower licensing process, it provides valuable information on baseline, or with-project, conditions that may allow for comparisons to the post-project river.