Concerned with enhancing white sturgeon spawning conditions in the Kootenai River, the U.S. Fish and Wildlife Service (USFWS) considered how far to extend the critical habitat reach upstream into the braided and (or) canyon reaches. The braided reach extends from U.S. Highway 95 Bridge at Bonners Ferry to near Crossport. The canyon reach extends from river mile 159.2 to Libby Dam. The streambed in the braided and canyon reaches is composed primarily of gravel and cobbles and is suitable for white sturgeon spawning. White sturgeon spawn in the meander reach (downstream of Bonners Ferry) of the Kootenai River, but the streambed in the meander reach is composed primarily of medium to fine sand, which is not ideal for spawning.
In 2005, we developed a one-dimensional hydraulic-flow model of a 65.6-mile reach of the Kootenai River in Idaho (Berenbrock, 2005). The primary use of the model was to locate the transition point between backwater and free-flowing water in the Kootenai River because many biologists believe that hydraulic changes at the transition affect where sturgeon choose to spawn.
The modeled reach starts at Leonia, Idaho, near the Montana/Idaho border and ends at Porthill, Idaho, near the United States/Canada border. The modeled reach also encompasses the white sturgeon spawning habitat reach (river mile 139.8 to 153.3) that has been designated as a critical habitat. The model has proven to be a useful tool to simulate hydraulic changes, especially in determining the location of backwater extent, and has served as a foundation for more recent hydraulic modeling efforts.
Barton, Gary J., 2004, Characterization of Channel Substrate, and Changes in Suspended-Sediment Transport and Channel geometry in White Sturgeon Spawning Habitat in the Kootenai River near Bonners Ferry, Idaho, Following the Closure of Libby Dam: U.S. Geological Survey Water-Resources Investigations Report 2003-4324.
Barton, Gary J., McDonald, Richard R., Nelson, Jonathon M., and Dinehart, Randal L., 2005, Simulation of flow and sediment mobility using a multidimensional flow model for the White Sturgeon critical-habitat reach, Kootenai River near Bonners Ferry, Idaho: U.S. Geological Survey Scientific Investigations Report 2005-5230.
Barton, Gary J., and Moran, Edward H., 2004, Surveying cross sections of the Kootenai River between Libby Dam, Montana, and Kootenay Lake, British Columbia, Canada: U.S. Geological Survey Open-File Report 2004-1045.
Berenbrock, Charles, 2005, Simulation of hydraulic characteristics of the white sturgeon spawning habitat of the Kootenai River near Bonners Ferry, Idaho: U.S. Geological Survey Scientific Investigations Report 2005-5110.
Berenbrock, Charles, 2006, Simulations of hydraulic characteristics in an upstream extension of the white sturgeon spawning habitat of the Kootenai River near Bonners Ferry, Idaho (a supplement to Scientific Investigations Report 2005-5110): U.S. Geological Survey Scientific Investigations Report 2006-5019.
Berenbrock, Charles, and Bennett, James, 2005, Simulation of flow and sediment transport in the white sturgeon spawning habitat of the Kootenai River near Bonners Ferry, Idaho: U.S. Geological Survey Scientific Investigations Report 2005-5173.