The Lost River watershed encompasses an areas of approximately 3,000 square miles in Klamath and Lake counties in Oregon, and Modoc and Siskiyou counties in California. The Upper Lost River originates in California at the outlet of Clear Lake, and flows north into Oregon, near the Malone Dame. The Lower Lost River continues downstream of Malone Dame, flowing northwest, where it receives substantial inflow from Gerber Reservoir, and then turns westward toward the Harpold Dam. Beyond the Harpold Dam, the Lower Lost River receives inflow of Klamath River water by way of the A-Canal and Lost River Diversion Channel. The Lost River Diversion Dam can also divert water to the Klamath River.
The Lower Lost River watershed is composed of two hydrologic subareas: the Tule Lake Hydrologic Sub Area and the Mt. Dome Hydrologic Sub Area.Keyword Tags: