Construction of the Friant-Kern Canal | Significance of the Friant-Kern Canal | Canal Components

Introduction

The Friant-Kern Canal was constructed by the U.S. Bureau of Reclamation in 1945‒1951 as part of the Central Valley Project (CVP). The 151.8-mile-long canal transports water southward by gravity flow from the Friant Dam at the San Joaquin River near Fresno, California to the Kern River in Bakersfield. The Friant-Kern Canal plays a primary role in accomplishing the CVP’s visionary goal—redistributing water from the State’s precipitation-heavy regions in the North to the drier regions of the Southern Central and San Joaquin Valleys. Today, the Friant-Kern Canal is operated by the Friant Water Authority, delivering irrigation water to more than 1 million acres of farmland and drinking water to over 250,000 San Joaquin Valley residents.

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Learn more about the Friant-Kern Canal, its development, and the many components that comprise it below.

Construction of the Friant-Kern Canal

Construction of the Friant-Kern Canal was completed in seventeen segments by nine different contractors. The construction effort required detailed planning and engineering by Reclamation’s principal engineer Harry Raymond McBirney and his team to overcome the numerous obstacles present along the 151.8-mile path. The canal traverses the rugged terrain of the Sierra Nevada foothills, crosses multiple waterways and roadways, and incorporates an assortment of irrigation infrastructure into its design and operation. The size and scale of the Friant-Kern Canal are an important achievement in engineering and construction. Upon its completion on June 29, 1951, it was the longest canal in California and had the third largest capacity in the state after the All-American Canal and the Delta-Mendota Canal.

Significance of the Friant-Kern Canal

Since 1951, the Friant-Kern Canal has provided Fresno, Tulare, and Kern counties with a reliable source of irrigation water and played a pivotal role in transforming the San Joaquin Valley into the top agricultural producing region in the United States. In the years immediately following its completion, the total amount of cultivated acreage within the San Joaquin Valley jumped and farmers began to transition towards more profitable, water intensive crops, such as alfalfa, grapes, nuts, rice, tomatoes, and citrus. Changes brought about by the Friant-Kern Canal caused the total agricultural value of land in Fresno, Tulare, and Kern counties to increase between 23 and 31 percent.

Canal Components

The Friant-Kern Canal extends 151.81 miles from the headworks at Friant Dam to the Kern River. Its components include the canal prism as well as numerous regulating, conveyance, and protective structures that assist in the canal’s operation and maintenance.

Canal Prism

The canal “prism” refers to the cross-section of the canal embankments and the canal bed and is typically trapezoidal in shape (wider at the water surface and narrower at the canal bed). The canal prism can be lined with concrete or earth.

Concrete-Lined Segments

Nearly 127 miles of the Friant-Kern Canal are lined with concrete. Concrete lined canals improve water conveyance efficiency over earthen-lined canals by limiting seepage and lowering channel roughness.

Earth-Lined Segments

The Friant-Kern Canal features three earthen-lined segments at mileposts 34.93, 57.14 and 119.5. The 25 miles of earthen segments are comprised of high plastic clays, silt, silty sand and/or sandy clay.

Check Structures

Check structures are used to raise the water level within a section of a canal to control the flow and distribution of water at turnouts or wasteways. Constructed of steel and concrete, the Friant-Kern Canal includes 14 of these structures.

Wasteways

Eight wasteways have been constructed into the canal embankment and are used to, among other things, divert surplus flows from the main canal into a natural or constructed channel to protect the canal system and support periodic maintenance.

Turnouts

Turnouts are concrete inlets set into the slope of the canal embankment and allow for the diversion of water for beneficial use. Metal screens cover most turnouts to limit intrusion of debris.

Monitoring Structures

Typically constructed of concrete or metal, monitoring structures are used to measure water level height and flow volume. They are positioned upstream and downstream of check structures.

Siphons

Siphons are underground concrete channels that transport water under existing structures or natural waterways. Siphons have a canal inlet and outlet and operate by gravity.

Overchutes

Overchutes are concrete flumes or steel pipes that pass over the top of the Friant-Kern Canal. These features usually convey drainage or stormwater runoff not suited by a siphon undercrossing.

Siphon Undercrossings and Culverts

Similar in function and construction, siphon undercrossings and culverts are concrete boxes that travel underneath the width of the Friant-Kern Canal to transport drainage and stormwater runoff.

Highway and Farm Bridges

Over 200 bridges carry vehicle and pedestrian traffic across the canal. County highway bridges and farm bridges are most common and are constructed with timber and/or concrete.

Operating Bridges

Twenty-three operating bridges are used for accessing important maintenance facilities and structures along the canal embankments. Most operating bridges were repurposed from former highway and farm bridges.

CVP Signs

Central Valley Project signs are positioned at various points along the canal to mark location. They list the Bureau of Reclamation and Friant-Water Authority as respective owner and operator of the canal.

Color photos in carousel above courtesy of Stephen D. Schafer.

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