General Description

The Sacramento Canals Unit of the Central Valley Project was designed to provide irrigation water in the Sacramento Valley, principally in Tehama, Glenn, and Colusa Counties. Authorized in 1950, the unit consists of Red Bluff Diversion Dam, Funks Dam, Corning Pumping Plant, Tehama-Colusa Canal, and Corning Canal. At the upper end of the Tehama-Colusa Canal are the Tehama-Colusa Fish Facilities, which Reclamation constructed  and the U.S. Fish and Wildlife Service (FWS) operates. Full and supplemental irrigation service is provided to about 98,000 acres.

In 1963, the U.S. Army Corps of Engineers finished building Black Butte Dam as a separate project. The Black Butte Integration Act of October 23, 1970, brought Black Butte Dam and Reservoir under the auspices of the Sacramento River Division as the Black Butte Unit.

Plan

Red Bluff Diversion Dam

Red Bluff Diversion Dam, a concrete gated weir structure 52 feet high and 5,985 feet long, including earth wings, is on the Sacramento River about 2 miles southeast of Red Bluff, California. It diverts water from the Sacramento River to the Corning and Tehama-Colusa Canals. Work began on the dam in 1962 and it was completed on August 9, 1964. The diversion capacity of the first sections of the two canals totaled 3,030 cubic feet per second.

Red Bluff Diversion Dam blocks the Sacramento River and interferes with fish moving upstream to their normal spawning grounds. Fish ladders at each abutment and subsurface openings in the dam alleviated the migration problem, but the subsurface openings led to a problem with predatory fish. Environmentalists equated salmon traveling through the subsurface openings, downstream through the dam, to putting the fish in a washing machine, disorienting the salmon when they get clear into the river. The disoriented fingerling salmon became easy prey for squawfish, which often lined up on the downstream side of Red Bluff Dam to feast on the small fish.

The population of winter-run chinook salmon at Red Bluff Diversion Dam peaked in 1969, numbering about 118,000. After 1969, the populations of migratory salmon and steelhead trout on the Sacramento steadily declined and eventually dropped to less than 5 percent of the 1969 total.

Construction of a drum screen structure, begun in 1969 and completed in 1971, was intended to prevent fish that passed through the headworks from entering the canals. A bypass system returned the fish to the river. In accordance with an agreement with FWS, Reclamation placed gravel beds along the upper 3.2 miles of the Tehama-Colusa Canal to simulate natural spawning beds. The artificial spawning beds failed to work as planned, and the canal headworks still trapped young fish.

In 1987, Reclamation began opening Red Bluff Dam's gates yearly, from December 1 until April 1, for the winter-run salmon returning to spawn at spawning grounds below Keswick Dam.  Inclusion of the winter-run chinooks on the listing of threatened species by the National Marine Fisheries Service (NMFS) prompted Reclamation to take further action. Reclamation completed a $17 million renovation of the dam in March 1990. The improvements included a temporary fish ladder in the center of the dam for passage when the gates remained closed. Renovations did not immediately boost the chinook population. In 1991, the adult, winter-run chinook count reached a record low of only 191 at Red Bluff Diversion Dam. The population increased in 1992 and 1993, with counts of 1,180 and 341 respectively. The NMFS redesignated the winter-run chinook as endangered in December 1993.

Corning Canal

The Corning Canal diverts water from the Tehama-Colusa Canal settling basin about 0.5 mile downstream from the Red Bluff Diversion Dam. The water is lifted 56 feet at the Corning Pumping Plant and delivered to lands in Tehama County that have elevations too high to be served from Tehama-Colusa Canal. The canal is 21 miles long, terminating about 4 miles southwest of Corning, California. The initial diversion capacity is 500 cubic feet per second, gradually decreasing to 88 cubic feet per second at the terminus.

Construction started in November 1954, and most of the main sections were completed on May 2, 1957. The inverted siphon under the Southern Pacific Railroad (now known as the Union Pacific)  and Highway 99 and the facilities for pumping water from the Sacramento River to the headworks of the canal were finished in July 1959.

Tehama-Colusa Canal

The Tehama-Colusa Canal receives water from the settling basin at Red Bluff Diversion Dam. The facilities consist of a drum screen complex to keep fish out of the dual-purpose canal and a single-purpose spawning channel that parallels the main canal for a short distance. The fish facilities provide 1.6 million square feet of special gravel-bottomed canal as a spawning area for salmon. These facilities are the largest of their kind in the world.

Groundbreaking ceremonies for the canal took place July 31, 1965. The fish facilities were completed on July 8, 1971. Reaches Six and Seven were completed on April 20 and July 3, 1979, respectively. Reach Eight, the final section of the canal, was complete on May 30, 1980.

The canal is 110.9 miles long, 11 miles shorter than originally intended.   It travels south from Red Bluff Diversion Dam through Tehama, Glenn, Colusa Counties, and into Yolo County, and terminates about 2 miles south of Dunnigan, California. The initial capacity of the canal is 2,530 cubic feet per second, diminishing to 1,700 cubic feet per second at the terminus. Funks Dam is located along the canal; the primary purpose of Funks Reservoir is to regulate canal flows.

Pumping Plants

Six pumping plants operate on the Sacramento Canals Unit. Five of the plants feed water to the Colusa County distribution system from the Tehama-Colusa Canal. The Corning Pumping Plant diverts water from the Sacramento River to the Corning Canal at Red Bluff Diversion Dam. Work was completed on the Corning Pumping Plant and intake channel in November 1960.

Development

The original authorization of the Central Valley Project in 1935, initiated construction of Shasta, Delta, and Friant Divisions.

 The Sacramento River Division's authorization came a decade and a half later. The President authorized the addition of the Sacramento Canals Unit to the CVP on September 29, 1950.

Benefits

Before construction of the Sacramento Canals Unit, over 45,000 acres in the Division's future service area received irrigation. In 1989, Tehama-Colusa and Corning Canals provided water for 100,019 acres, on which $88,529,000 worth of crops grew; the Tehama-Colusa Canal supplied water for 20,000 acres of the Sacramento Valley (wildlife) Refuges.

Lake Red Bluff provides recreational opportunities in the form of sailing, jet skiing, water skiing, and drag boat racing.

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