3. and Reservoir Clear Lake Dam is located in California on the about 39 miles southeast of Klamath Falls, Oregon, and provides storage for irrigation and reduced flow into the reclaimed portion of and the restricted Tule Lake Sumps in Tulelake National Wildlife Refuge The dam is an earth and rockfill structure with a crest length of 840 feet and a height of 36 feet above the streambed. The crest of the dam is at elevation 4,552.0 feet and is 20 feet wide. At the normal maximum water surface elevation of 4,543.0 feet, the dam will impound a total of 527,000 acre- feet in Clear Lake Reservoir. Clear Lake has earthen Dikes which are located at the south end of Clear Lake and provide protection to the Tulelake homesteaded lands. There are two dikes that are interconnected and are both earth core and rip-rap protected. The Main dike runs east and west and was constructed when the stop logs were placed in the spillway in the late 1930's. The South Dike runs southeast and was constructed in 1974 when the spillway was raised permanently. The dikes do not become operative until surcharge on the reservoir is reached.

The spillway structure consists of a concrete overflow weir and side channel located at the left abutment of the dam. With a crest elevation of 4,543.0 feet, the overflow weir is 357 feet in length and has a rated capacity of 5,650 cfs at 2.7 foot depth of flow (Water Surface Elevation 4,545.7 ft). The spillway was reconstructed in 1974. The Outlet works consist of an Outlet Tunnel comprised of two 53" high x 4'0" wide outlet tubes which extend from the base of the outlet control structure at the upstream face of the dam, to a point approximately 31 feet downstream where they merge into one 7 ft x 7 ft arched outlet tunnel. Two screw-lift outlet gates are located in the outlet control structure, each 4 ft wide by 4'9" high. Each gate is raised and lowered by a hand-cranked screw-lift assembly. A portable power unit is available to power the gate- mechanism (USBR Web). Prior to the construction of the dam a natural lake and marshlmeadow existed. The meadow was seasonally farmed by the Carr Livestock Company. During most years the Lost River below the present dam would run dry from June through October. Historic elevations are included in the appendix.

The outlet at Clear Lake is opened in the spring, usually around April 15, to provide irrigation water to LVID, Horsefly Irrigation District (HID) and private "Warren Act" contract lands. In most years the outlets are shut off around October 1. No other releases are made from the dam unless an emergency condition dictates otherwise. Since the reservoir has a storage limitation of 350,000 acre-feet from October 1 through March 1, summer drawdown releases are occassionally necessary. A purchase order is issued each year that permits LVID to operate the dam on a reimbursable basis. LVID operates the gates and reports the changes to Reclamation on a daily basis. Flow changes are dictated by the needs of HID and LVID and the private users along the Lost River. During the non-irrigation season Reclamation operates the dam and reservoir. The reservoir is managed to store as much water as possible without encroaching on the operational guidelines. The target elevation after March 1 is 4537.4. Should inflow cause this elevation to be exceeded the water must be released in a timely manner until that elevation is reached. During the irrigation season the dam is visited approximately twice a week and, during the winter, once a month.

Section II, Part 1, Page 22