Lake Lowell is fed by water from the Boise River through the New York Canal, forming one of the largest off-stream impoundments in the West. The Bureau of Reclamation manages lake water for irrigation. Normal lake operation provides for the habitat needs of a wide variety of migratory birds. During spring and summer, water is released from Lake Lowell to irrigate surrounding farm fields. This slow draw-down of the lake exposes mudflats that provide abundant habitat for shorebirds.

The Snake River Islands sector encompasses 101 islands along 113 miles of the Snake River in southwestern Idaho and eastern Oregon. Objectives are to preserve and maintain habitat for all native species. The islands (<1 acre to 58 acres, 4-10 feet above mean river level) are especially important to nesting Canada geese of the southwest Idaho flock. Upstream islands have grass/sagebrush centers and are ringed by willow and other riparian vegetation. Downstream islands are more heavily vegetated, with grassy centers bordered by larder trees such as willows, cottonwoods, and Russian olives.