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San Felipe Division Project
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San Felipe Division Project History (55 KB) (pdf)
General Description| Plan| Development| Benefits

General Description

The San Felipe Division of the Central Valley Project, in the central coastal area of California, embraces the Santa Clara Valley in Santa Clara County, the northern portion of San Benito County, the southern portion of Santa Cruz County, and the northern edge of Monterey county. Authorized in 1960, the division provides supplemental water to 63,500 acres of land, in addition to 132,400 acre-feet of water annually for municipal and industrial use. Water from San Luis Reservoir is transported to the Santa Clara-San Benito service area through Pacheco Tunnel and other project features which include 48.5 miles of closed conduits, two pumping plants, and one small reservoir. Provisions for future construction of about 25 miles of closed conduit to Santa Cruz and Monterey counties are included in the division features.

Water is conveyed from the Delta of the San Joaquin and Sacramento Rivers through the Delta-Mendota Canal to O`Neill Forebay. The water is then be pumped into San Luis Reservoir and diverted through the 1.8 miles of Pacheco Tunnel Reach 1 to the Pacheco Pumping Plant. At the pumping plant, the water is lifted to the 5.3-mile-long high-level section of Pacheco Tunnel Reach 2. The water flows through the tunnel and, without additional pumping, through the Pacheco Conduit to the bifurcation of the Santa Clara and Hollister Conduits. The water is then conveyed throughout the service areas for irrigation and municipal uses.

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Facility Descriptions

San Justo Dam and Reservoir

San Justo Dam, located about 3 miles southwest of Hollister, is an earthfill structure 151 feet high with a crest length of 1,116 feet. A dike structure 79 feet high with a crest length of 1,296 feet is required. These features forms a reservoir with a 9,785 acre-foot capacity.

Hollister Conduit

The 19.5-mile-long Hollister Conduit has a capacity of 83 cubic feet per second and extends from the Pacheco Conduit to San Justo Reservoir.

Pacheco Conduit

The 7.92-mile-long Pacheco Conduit, with a capacity of 480 cubic feet per second, will extend from the Pacheco Tunnel Reach 2 outlet to the bifurcation of the Santa Clara and Hollister Conduits.

Santa Clara Tunnel and Conduit

Santa Clara Tunnel and Conduit is 22.1 miles long and has a capacity of 330 cubic feet per second. It conveys water from the Pacheco conduit to the Coyote Pumping Plant.

Pacheco Tunnel

Both reaches of the Pacheco Tunnel, totaling 7.1 miles, are 9.5 feet in diameter and have capacities of 480 cubic feet per second. Both reaches, along with the Pacheco Pumping Plant, bring water from San Luis Reservoir through the Diablo Mountain Range.

Pumping Plants and Switchyards

Division facilities will include two pumping plants and two related switchyards. The Pacheco Pumping Plant is located at the end of Pacheco Tunnel Reach 1, and the Coyote Pumping Plant is located at the end of the Santa Clara Conduit, near Anderson Dam.

Operating Agencies
  • Santa Clara Valley Water District (SCVWD) manages Santa Clara Tunnel and Conduit, Pacheco Tunnel and Conduit, Pacheco and Coyote Pumping Plants.   Western Area Power Administration (WAPA) manages Pacheco Switchyard, San Benito County Water District (SBCWD manages San Justo Dam and Reservoir and Hollister Conduit

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The first significant development of the Santa Clara Valley was the establishment of Spanish missions. Mission Santa Clara, from which the valley derived its name, was founded in 1777 at the northern edge of the present city of Santa Clara. Other Spanish settlements were the Pueblo de San Jose de Guadalupe, at the site of the present city of San Jose, and the Mission San Juan Bautista. Although early farm activities consisted of growing fruit trees and non-irrigated crops and breeding livestock, some irrigation was started at an early date at the Mission San Juan Bautista. However, cattle ranching was the predominant industry on the large Mexican land grants.

The lower Pajaro River Basin was first settled for farming around 1851. Construction of the Southern Pacific Railroad through Pajaro Gap in 1870 stimulated agriculture, and by 1880, commercial fruit growing became important. In 1886, a sugar beet factory was built in Watsonville.

Irrigated agriculture developed rapidly when pump designs improved and electric power became available. Groundwater was readily available in most of the area, and farmers made extensive use of the supply.

Northern Santa Clara County experienced a large influx of military personnel and civilians during and after World War II. Industrial development was greatly accelerated in the vicinities of San Jose, Sunnyvale, Mountain View, and Milpitas. Tremendous urban expansion took place and continued at a rapid pace. Demands on groundwater far exceeded the supply, and local resources were inadequate.


The initial investigation that eventually led to the San Felipe Division was the Pajaro River Basin investigation authorized by the Congress in 1948. The resulting reconnaissance report pointed out the groundwater overdraft in the area and recommended that an organization be formed to consider importing water.

Also in 1948, the State of California initiated investigations of the Santa Clara Valley under joint sponsorship of the State, the Santa Clara County Board of Supervisors, and the city of San Jose.

On July 29, 1955, California sent the Secretary of the Interior a joint resolution requesting that the Congress take action to initiate feasibility studies. Congressional action came in August 1958, when House Joint Resolution 585 directed the Secretary of the Interior to investigate the possibility of providing service from the Central Valley Project to Santa Clara, San Benito, Santa Cruz, and Monterey Counties.

On June 22, 1959, a cooperative investigation contract between the United States and the Santa Clara-Alameda-San Benito Water authority was signed. In a May 1963, this investigation culminated in a Reclamation feasibility report on the San Felipe division. After review by all interested Federal, State, and local agencies, the report was revised and submitted to the Commissioner of Reclamation on March 31, 1964. This report was the basis for the Commissioner`s proposed report to the Secretary of the Interior, who submitted the final report to the Speaker of the House of Representatives on September 26, 1966. The report was subsequently printed as House Document No. 500, 89th Congress, 2nd session.


  • The initial authorization for construction of elements of the San Felipe Division came in an amendment to the San Luis Unit authorization of June 1960.
  • The San Felipe Division, Central Valley Project, was authorized for construction by Public Law 90-72, dated August 27, 1967 (81 Stat. 173).

Construction on the San Felipe Division began in 1964 with work on the intake structure and Pacheco Tunnel Reach 1. Work on the intake channel began on November 4, 1964, and was completed on April 13, 1965. Excavations for the shaft of the intake structure began on March 4, 1965, and were completed on March 26. Initial tunneling activities began on April 25, 1965, and were completed on February 23, 1968. Construction of the remaining project features was delayed for more than a decade for a variety of reasons, including fiscal austerity, the rise of the environmental movement, an energy crisis, and inflation. Excavation on the inlet end of Pacheco Tunnel Reach 2 began on April 18, 1979, and in late May, the company began drilling and excavating the outlet end. Finishing work was completed on January 26, 1983.

Work began on the Pacheco Pumping Plant, which lifts water from the lower tunnel to the upper tunnel, on March 23, 1983. Pacheco Tunnel Reach 2 was filled with water for the first time in October 1986. On March 19, 1987, Reclamation accepted the work as substantially complete. The pumping plant consists of twelve 2,000 horsepower pumps capable of lifting water 309 feet and a 50-foot-diameter regulating tank which holds over 3 million gallons. Pacheco Tunnel and Pumping Plant allow San Luis Reservoir water to be moved through the Diablo Mountains for agricultural and industrial use.

After water is delivered through Pacheco Tunnel, it enters the Pacheco Conduit. The Pacheco Conduit, a 120-inch-diameter concrete pipe, delivers the water to the Hollister and Santa Clara Conduits. Reclamation divided construction the Pacheco Conduit into two sections. Excavation of section one began in 1983 and section two in 1984. Construction was complete in September 1986. Pacheco Conduit starts at the Pacheco Tunnel outlet and runs underground in a southwesterly direction for 7.92 miles. At the end of the pipe, water enters a bifurcation structure that separates the water between the Hollister and Santa Clara Conduits.

Water for Santa Clara, Monterey, and Santa Cruz is transported from the bifurcation structure via the Santa Clara Conduit and Tunnel. Work was divided into four sections, three sections of conduit and the tunnel. Santa Clara Tunnel, section four, was the first structure built. The concrete-lined tunnel is approximately one mile long, with a diameter of 9.79 feet. It runs through the western foothills of the Diablo Mountains. Operations commenced on September 14, 1981, and the tunnel was accepted as complete on December 20, 1983. Work on sections one and two was completed by April 1987, and section three was completed by May 6, 1987.

Hollister Conduit is buried underground and runs for approximately 19.5 miles from the Pacheco Conduit to San Justo Dam and Reservoir. Construction of this facility was divided into two sections. Excavation and installation of section one, about 2 miles of conduit, was completed on September 18, 1981. Section two consisted of the excavation and installation of about 17 miles of conduit ranging in size from 60 to 42 inches inside diameter. Since the conduit crosses the Calaveras Fault, part of the conduit is constructed with 679 feet of steel carrier pipe inserted in a 120-inch diameter reinforced concrete casing pipe to allow the carrier pipe to move independently of the casing pipe. The Hollister Conduit was completed in May 1987.

San Justo Reservoir, completed in January 1986, serves as an offstream storage facility. Water from Hollister Conduit is stored in the reservoir and is released during the winter months. San Justo Dam and a dike are the primary features this facility. The dam is a zoned earth and rockfill dam, 151 feet high, with a crest 1,116 feet long. The reservoir`s capacity is 9,785 acre-feet. The dike is a zoned earth structure, 79 feet high, with a crest 1,296 feet long. To control seepage, Reclamation installed a 40-millimeter-thick, high-density, polyethylene membrane liner in the reservoir which was covered with earthfill to protect it against damage.

Topsoil stripping began within the dam and dike areas during March 1985. The emergency spillway, located on the northeastern rim of the reservoir, is an open-cut channel lined with grass to protect against weathering and erosion. The outlet works, also located on the northeastern side of the reservoir, include a 1,500-foot-long tunnel, 688 feet of buried 60-inch-diameter pipe, and a 23.1-foot-diameter shaft about 135 feet deep that terminates at a gate.

To protect against seismic damage, the 60-inch steel carrier pipe is run through an 84-inch-diameter concrete pipe filled with grout which acts as a cushion and allows the carrier pipe to move independently of the concrete pipe. The contract was finished by September 1986, and in 1987, all features necessary to deliver water throughout the San Felipe Division were complete. The first water deliveries began in June.

Storage Issues: 

in 2003, SBCWD voluntarily lowered the reservoir by 15 feet which has reduced some of the seepage.  The storage capacity is about 7,200 acre-feet after 2003

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The primary recipients of water from the San Felipe Division are municipal and industrial users. In 1991, non-agricultural users received over 46,000 acre-feet of project water. Just over 15,000 acre-feet went to agricultural customers to provide supplemental irrigation to slightly more than 24,000 acres.

Average crops values per acre on lands irrigated in San Benito and Santa Clara counties were $2,955.32 and $4,198.20 respectively, with a combined 1991 value of $71,944,828.00 for 24,089 irrigated acres.


Various.  Check out your specific interests at recreation.gov  

In addition, Recreation facilities are being administered at San Justo reservoir by the County of San Benito, through the Recreation Department


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Last updated: Apr 21, 2011