The Madera Canal is a 35.9-mile (57.8 km) aqueduct in central California. It is part of the U.S. Bureau of Reclamation’s

Central Valley Project The Central Valley Project (CVP) is a federal power and water management project in the U.S. state of California under the supervision of the United States Bureau of Reclamation (USBR). It was devised in 1933 in order to provide irrigation and ...

(CVP) and conveys water northward from Friant Dam ( Millerton Lake) to augment irrigation in Madera County. Completed in 1945, the canal has an initial capacity of about 1,000 cubic feet per second (cfs) (28 m³/s), gradually decreasing to 625 cfs (17.7 m³/s) at its terminus at the Chowchilla River. In 1965, its headworks at Friant Dam were rebuilt to increase the peak delivery capacity to 1,250 cfs (35 m³/s). The Madera Canal supplies water to thousands of acres of farmland and remains a key component of the CVP’s Friant Division. It was also the subject of a

United States Supreme Court The Supreme Court of the United States (SCOTUS) is the highest court in the federal judiciary of the United States. It has ultimate appellate jurisdiction over all U.S. federal court cases, and over state court cases that turn on question ...

case, '' Central Green Co. v. United States'' (2001), which addressed liability for flood-related damage along the canal.Bureau of Reclamation. "Central Valley Project: Overview and Operations." U.S. Department of the Interior, 2021

https://www.usbr.gov/cvp/)

Historical Background

Planning and Construction

The concept of the Madera Canal originated in local irrigation plans in the early 20th century. The Madera Irrigation District (MID), formed in 1914, had initially envisioned building a dam on the

San Joaquin River The San Joaquin River ( ; ) is the longest river of Central California. The long river starts in the high Sierra Nevada and flows through the rich agricultural region of the northern San Joaquin Valley before reaching Suisun Bay, San Francis ...

in the late 1920s to provide a reliable water supply, even acquiring a dam site at Friant.Madera Irrigation District. "The History of the Madera Irrigation District." Madera Irrigation District, 2020

https://www.maderaid.org/history) However, financial obstacles and water rights disputes delayed those efforts. The federal CVP incorporated these plans when Congress authorized the Friant Division in 1935–1936. Construction of Friant Dam began in 1939 and the Madera Canal in 1940.U.S. Bureau of Reclamation. "Friant Division: Central Valley Project." U.S. Department of the Interior, 2018

https://www.usbr.gov/projects/) Work on the canal was slowed by material shortages during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, but some test water diversions into partially built sections occurred as early as 1944. The canal was fully completed and operational by 1945, shortly after Friant Dam’s completion in 1944. Early operations were limited; in the late 1940s the canal ran below capacity because distribution laterals had not yet been finished and because negotiations were ongoing over federal reclamation law’s 160-acre ownership limits for irrigation recipients. By around 1950, the Madera Canal reached its intended capacity and began delivering water at full volume to local districts.U.S. Bureau of Reclamation. "Operations of the Madera Canal and Friant Dam." U.S. Department of the Interior, 1950

https://www.usbr.gov/projects/)

Initial Purpose and Significance

The Madera Canal was built as one of two main CVP canals fed by Friant Dam (the other being the Friant-Kern Canal to the south) to distribute

water for irrigation. The canal’s completion in 1945 brought a new, dependable water supply to farmlands in Madera and Chowchilla areas, supplementing or replacing unreliable local sources. This enabled the conversion of many thousands of acres of semi-arid land into productive agriculture. For example, the Chowchilla Water District (CWD) was formed in 1949 (out of the original MID territory) specifically to use Friant water, and MID and CWD soon signed long-term contracts for CVP deliveries.Chowchilla Water District. "History of Chowchilla Water District." Chowchilla Water District, 2021

https://www.cwd.org/) The canal’s opening was heralded as a major milestone in regional development, as it allowed new orchards and crops to flourish with a stable surface water supply, reducing dependence on groundwater. By the mid-20th century, the Friant Division (including Madera Canal) was helping irrigate a large portion of the San Joaquin Valley; by 1955 about 4.5 million acres of land valley-wide were irrigated with water from federal CVP canals.U.S. Bureau of Reclamation. "Central Valley Project History: 1940s–1950s." U.S. Department of the Interior, 1955

https://www.usbr.gov/projects/)

Later Modifications

In 1965, the canal’s intake facilities at Friant Dam (the headworks) were reconstructed to improve capacity and flow control.U.S. Bureau of Reclamation. "Friant Dam and Madera Canal Headworks Reconstruction." U.S. Department of the Interior, 1965

https://www.usbr.gov/projects/) This upgrade increased the maximum discharge from the dam into the Madera Canal from the original design of 1,000 cfs to about 1,250 cfs. The modification was likely driven by the need to deliver greater Class 2 (surplus) water during wet years and to enhance operational flexibility. No major length extensions were made, as the canal already reached its planned terminus at the Chowchilla River, but the higher flow capability allowed more water to be moved when available. Aside from the 1965 headworks project, the canal’s general route and structure have remained largely unchanged, with ongoing maintenance to repair lining, gates, and other features over the decades.

Engineering and Design Details

Canal Structure

The Madera Canal is a gravity-flow earthen and concrete

canal Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface ...

that runs north along the foothills on the eastern edge of the

San Joaquin Valley The San Joaquin Valley ( ; Spanish language in California, Spanish: ''Valle de San Joaquín'') is the southern half of California's Central Valley (California), Central Valley. Famed as a major breadbasket, the San Joaquin Valley is an importa ...

. It begins at the Friant Dam outlet on Millerton Lake (elevation \~580 feet) and gently slopes northward, terminating at a point on the Chowchilla River (an area used as a distribution channel). The total length is about 36 miles, and there is no significant lift or pump station along the route (flow is driven by the head from Friant Dam). Over most of its length, the canal is concrete-lined, which improves flow efficiency and reduces seepage. In several downstream sections, however, the canal was constructed as a larger earthen channel without concrete lining (to save cost and because lower flows there have less erosive force). The typical cross-section differs between these segments: in the lined reaches, the canal has a narrow trapezoidal profile (approximately 10 feet bottom width, 9 feet depth, 24 feet top width). In the unlined (earthen) reaches, the canal is wider and shallower (roughly 20-foot bottom width, 9-foot depth, with much wider top width to maintain stability of the banks). The lined sections are built with concrete to minimize erosion and vegetation, while the unlined sections rely on gentle side slopes to prevent slumping. The canal’s design addresses local geography, such as box

flume A flume is a human-made channel for water, in the form of an open declined gravity chute whose walls are raised above the surrounding terrain, in contrast to a trench or ditch. Flumes are not to be confused with aqueducts, which are built to t ...

overchutes that allow intermittent streams from the Sierra foothills to cross above the canal without eroding the channel.U.S. Bureau of Reclamation. "Madera Canal Design and Engineering Overview." U.S. Department of the Interior, 1945

https://www.usbr.gov/projects/)

Capacity and Flow Controls

The canal was originally designed for a **maximum flow capacity** of 1,000 cfs at the head, gradually tapering as water is diverted by turnouts to farms and districts. By the end of the canal at Chowchilla River, the design capacity is about 625 cfs. After the 1965 headworks reconstruction, the upstream intake can accommodate peaks of up to 1,250 cfs, although sustained flows at that level are rarely needed except in very wet years. Numerous hydraulic structures are integrated along the canal, including check gates (control structures) that regulate water levels, and turnouts that deliver water into lateral canals or pipelines serving farms. According to historical records, by the time the canal was completed, it featured dozens of turnouts and control structures – for example, an inventory noted 5 check structures, 51 farm turnouts, 8 wasteways (spill gates), and 11 “overchutes” where local creeks or drains are carried *over* the canal in flume-like bridges.U.S. Bureau of Reclamation. "Madera Canal Operational Review." U.S. Department of the Interior, 1945

https://www.usbr.gov/projects/)

Materials and Construction

The canal prism was constructed mostly by excavation and embankment of local soil materials, with concrete lining poured in place along critical stretches. Most of the canal’s concrete is around 4 to 6 inches thick cast-in-place, typical for CVP canals of that era. The project was built in sections by multiple contractors between 1940 and 1945, with standard Bureau of Reclamation designs. The canal’s path was engineered to follow the contour of the terrain, staying at a roughly constant elevation along the valley’s east side, minimizing the need for deep cuts or high fills. Where the canal crosses valleys or ravines, earth fill embankments were used to carry it above grade, and in a few places, the canal is built up on an embankment above natural ground level. To manage flows and prevent overflow, the canal banks were designed with freeboard (extra height above the water line). The Madera Canal’s construction also included the Friant Dam outlet works modifications: Friant Dam was built with an intake on its right abutment specifically for the Madera Canal, equipped with large hollow-jet valves to release water from the reservoir into the canal headworks.U.S. Bureau of Reclamation. "Construction Materials and Practices for the Madera Canal." U.S. Department of the Interior, 1945

https://www.usbr.gov/projects/)

Operational Role and Water Delivery

The primary purpose of the Madera Canal is to deliver irrigation water from Millerton Lake ( Friant Dam) to agricultural lands in Madera County. It serves as the main conveyance for CVP water in the area north of the

. The canal flows generally west-northwest from Friant, hugging the base of the Sierra Nevada foothills, and supplies water to two major irrigation districts: Madera Irrigation District (MID) and Chowchilla Water District (CWD). All CVP water delivered to MID and CWD is conveyed through the Madera Canal. MID’s contract (initially signed in 1951) entitles it to up to 85,000 acre-feet of “Class 1” water (firm supply) and 186,000 acre-feet of “Class 2” water (surplus supply) per year. CWD’s contract (since 1949) provides for 55,000 acre-feet of Class 1 and 160,000 acre-feet of Class 2 water annually.Madera Irrigation District. "Madera Canal Water Deliveries and Allocation." Madera Irrigation District, 2020

https://www.maderaid.org/water-delivery)

Legal and Environmental Impact

Supreme Court Case (Central Green Co. v. United States)

The Madera Canal was at the center of an important legal decision regarding government liability for flood damage. In the 1990s, a farming company, Central Green Co., sued the United States, claiming that the Madera Canal’s design and operation caused subsurface flooding that damaged its pistachio orchards. The case clarified that infrastructure like the Madera Canal, used for irrigation delivery, is not automatically exempt from tort liability just because it is connected to a larger flood control system.U.S. Supreme Court. "Central Green Co. v. United States." Oyez, 2001

https://www.oyez.org/cases/2000/99-1652)

Current Status and Ongoing Improvements

As of the mid-2020s, the Madera Canal remains an essential piece of irrigation infrastructure in the San Joaquin Valley. It continues to be operated by MID under Bureau of Reclamation oversight to deliver CVP water to about 130,000 acres in Madera County and a portion of neighboring Merced County. The infrastructure is now over 75 years old, and maintenance and upgrades are an ongoing concern.U.S. Bureau of Reclamation. "Ongoing Improvements to Madera Canal Infrastructure." U.S. Department of the Interior, 2021

https://www.usbr.gov/projects/)

References

External links

Central Valley Project - Friant Division
Bureau of Reclamation
USGS flow data
* {{Central Valley Project infrastructure Agriculture in California Transportation buildings and structures in Madera County, California Central Valley Project Irrigation in the United States Aqueducts in California San Joaquin River United States Bureau of Reclamation 1945 establishments in California Transport infrastructure completed in 1945