The Lake Roosevelt Rainbow Trout Habitat/Passage Improvement Project is a resident fish substitution project intended to mitigate for anadromous fish losses caused by the construction and operations of Chief Joseph and Grand Coulee Dams. The goal of the project is to increase natural production for Tribal subsistence.  This substitution of resident fish for anadromous fish losses is considered in-place and out-of-kind mitigation and is in accordance with the Resident Fish Substitution Policy.
The Project proposes to enhance natural production and survival of resident fish for recreation and Tribal subsistence with the implementation of several management actions designed to address habitat related limiting factors and restore the natural hydrologic function of the systems. EDT and QHA sixth level HUC analysis indicated the greatest limiting factors for most of the Sanpoil and Upper Columbia Subbasin’s tributaries were identified in the Subbasin plans as obstructions, summer temperatures, flows, and sediment load (IMP Subbasin Plan 2004). Additionally nutrient imbalance limits growth and diversity with most streams being both nitrogen and phosphorus limited.
The land uses that have contributed to these limitations include cattle grazing, timber harvest, road construction and density, cut bank roads, irrigation withdrawal, restrictions of the natural channel migration with culverts and bridges, removal of riparian vegetation, agriculture, mining, and the loss of carbon and marine derived nutrients from anadromous carcasses.