Impact analyses covered cultural resources, endangered and threatened species, protection of refuge and riparian habitats, irrigation, and flood control. Clear Lake Dam is in California's Modoc County about 19 miles southeast of Malin, Oregon. Part of the Klamath Project, it was constructed in 1910 and later raised 3 feet in 1938. The lake occupies a broad, flat alleviated basin in barren volcanic terrain. Lake capacity is 526,770 acre-feet at spillway crest elevation 4543.0, with a corresponding surface area of 25,760 acres.
Reclamation is responsible for the dam and lake.
Irrigation water is delivered by the United States to Langell Valley Irrigation District, Horsefly Irrigation District, and others including East Malone Lateral Warren Act contractors, Klamath Irrigation District and Tule Lake Irrigation District. Lands surrounding the refuge are part of the Modoc National Forest administered by the U.S. Forest Service. Clear Lake is remote, and visits by the public are infrequent.