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Millerton Lake
View on WikipediaMillerton Lake is an artificial lake near the town of Friant, about 15 mi (24 km) north of downtown Fresno, California, United States. The reservoir was created by the construction of 319 ft (97 m) high Friant Dam on the San Joaquin River which, with the lake, serves as much of the county line between Fresno County to the south and Madera County to the north.
Key Information
Part of the Central Valley Project, the dam was built by the United States Bureau of Reclamation (USBR) and was completed in 1942 with the exception of the drum gates being installed in 1947.[1] The lake stores water for irrigation, which is distributed by the Madera and Friant-Kern Canals to the San Joaquin Valley. It has an instantaneous capacity of 520,528 acre⋅ft (0.642062 km3).
Secondary uses include flood control and recreation, including swimming, fishing, water skiing and camping. A 25 MW hydroelectric plant operated by the Friant Power Authority produces electricity from large releases and two smaller plants use water released for a fish hatchery and to maintain minimum-flow in the river.
Prior to the construction of Friant Dam, the current lake bed was the site of the town of Millerton, the first county seat of Fresno County.
The California Office of Environmental Health Hazard Assessment has issued a safe eating advisory for fish caught in the Millerton Lake due to elevated levels of mercury.[2]
Environmental impacts
[edit]By diverting most of the San Joaquin River for irrigation, the Friant Dam has caused about 60 miles (97 km) of the river to run dry except in high water years when floodwaters are spilled from the dam. The desiccation of the river has caused the degradation of large stretches of riverside habitat and marshes, and has nearly eliminated the historic chinook salmon run that once reached about 15,000 fish each year. Reduction in flows has also increased the concentration of pesticide and fertilizer runoff in the river contributing to pollution that has further impacted aquatic species.[3]
On September 13, 2006, after eighteen years of litigation, environmental groups, fisherman and the USBR reached an agreement on releasing part of the water currently diverted into the irrigation canals into the San Joaquin River in order to help restore the river and its native fish and wildlife. The first water was released on October 2, 2009, at a rate of 185 cubic feet per second (5.2 m3/s).[4] By 2014, these "restoration flows" were scheduled to be increased to 302,000 acre-feet (373,000 dam3) per year, or 417 cubic feet per second (11.8 m3/s), on top of the 117,000 acre-feet (144,000 dam3) that was originally released for agricultural purposes. However, the river restoration project will cause a 12–20% reduction in irrigation water delivered from Friant Dam.[5]
See also
[edit]- List of dams and reservoirs in California
- List of lakes in California
- List of largest reservoirs of California
- Temperance Flat Dam - proposed extension of Millerton Lake
References
[edit]- ^ "Friant Division Facts" (PDF). Archived from the original (PDF) on 2021-02-09.
- ^ OEHHA, Admin (2019-04-16). "Millerton Lake". oehha.ca.gov. Retrieved 2019-04-23.
- ^ "Restoring the San Joaquin River: Following an 18-year legal battle, a great California river once given up for dead is on the verge of a comeback". Natural Resources Defense Council. Retrieved 2012-04-05.
- ^ Sheehan, Tim (2009-10-02). "Friant Dam releases water to begin river rebirth". The Fresno Bee.
- ^ "Restoration Flows" (PDF). Friant Water Authority. Archived from the original (PDF) on 2012-04-07. Retrieved 2012-04-05.
- Department of Water Resources (2011). "Station Meta Data: Friant Dam (Millerton) (MIL)". California Data Exchange Center. State of California. Retrieved 24 August 2011.
- Central Valley Project Friant Division (4 June 2009). "Friant Dam". U.S. Bureau of Reclamation. Retrieved 24 August 2011.
- Central Valley Project Friant Division (21 April 2011). "Friant Division Project". U.S. Bureau of Reclamation. Retrieved 24 August 2011.
External links
[edit]Millerton Lake
View on GrokipediaGeography and Hydrology
Location and Formation
Millerton Lake is an artificial reservoir located in the Sierra Nevada foothills of Fresno and Madera counties, California, approximately 15 miles northeast of downtown Fresno.[2] It occupies the upper San Joaquin River watershed within the southern portion of the Central Valley.[2] The lake's approximate central coordinates are 37°00′N 119°40′W.[6] The reservoir formed through the impoundment of the upper San Joaquin River by Friant Dam, a structure integral to the Central Valley Project (CVP), a federal initiative launched in the 1930s to manage water resources for irrigation, flood control, and power generation across California's Central Valley.[1] [5] Friant Dam, situated near the town of Friant, backs up river flows to create the lake, which serves as the primary storage facility for the Friant Division of the CVP.[1] At full pool, the lake reaches an elevation of approximately 561 feet (171 m) above mean sea level.[7] The surrounding terrain encompasses the Blue Oak Woodland and Interior Chaparral biomes, characterized by oak savannas, chaparral shrubs, and associated foothill ecosystems.[8]
Physical Characteristics and Capacity
Millerton Lake possesses a total storage capacity of 520,500 acre-feet, with usable storage comprising the volume above the inactive pool.[9] [5] At maximum pool elevation of 578 feet, the reservoir's surface area spans 4,900 acres, though this fluctuates with water levels and seasonal drawdowns.[9] The reservoir's primary inflows originate from the San Joaquin River, driven by snowmelt from Sierra Nevada headwaters and contributions from tributaries including the North Fork San Joaquin and Fine Gold Creek, with annual volumes varying significantly based on precipitation and runoff patterns.[5] Outflows are regulated through river outlets, the Madera and Friant-Kern Canals, and the drum-type spillway gates during periods of excess inflow to prevent overtopping.[10] In wet years characterized by high Sierra snowpack, such as 2023, Millerton Lake has filled to capacity and initiated spillway releases, demonstrating the infrastructure's operational constraints amid California's variable hydroclimate where inflows can surpass design limits.[11] This event underscored the reservoir's reliance on flood control mechanisms, as storage exceeded the nominal 520,500 acre-feet threshold temporarily before managed releases restored balance.[5]Historical Development
Pre-Construction Era
The area encompassing the future site of Millerton Lake was originally inhabited by Northern Foothill Yokuts peoples for thousands of years prior to European contact, who established villages in the rolling grasslands and woodlands along the San Joaquin River, relying on its seasonal flows for fishing, hunting, and gathering acorns and other resources essential to their sustenance.[8] The Yokuts, part of a diverse group of up to 60 tribes in central California, adapted to the river's natural regime of high winter and spring flows from Sierra Nevada snowmelt, which supported riparian ecosystems, tule marshes, and migratory fish populations like salmon, though these were disrupted by early 19th-century overtrapping by fur traders.[8] European-American settlement began during the California Gold Rush, with Camp Barbour established in 1850 along the San Joaquin River as a military outpost amid conflicts with local tribes, later evolving into Fort Miller by 1851 to secure the region for miners and settlers.[8] A tent city known as Rootville emerged nearby, renamed Millerton by 1853, which became the first county seat of Fresno County upon its formation in 1856, serving administrative functions including a courthouse built in 1867 at a cost of $24,000; the town's location leveraged the river for transportation, water supply, and proximity to mining operations, though it remained isolated without rail access.[8][12] The unregulated San Joaquin River posed significant flood risks throughout the 19th century, exemplified by the Great Flood of 1862, which inundated much of the Central Valley, destroying settlements and prompting early levee construction attempts to protect agricultural lands in the arid San Joaquin Valley, where summer flows dwindled naturally, limiting irrigation to sporadic diversions. By the late 1800s, ranchers and farmers recognized the valley's potential for large-scale agriculture but faced chronic water shortages and flood damages, fueling advocacy for storage and distribution systems.[13] This culminated in federal surveys during the 1920s, including reports on river flows, droughts, and irrigation feasibility, which documented the need to harness the river's untapped winter surplus for valley development while mitigating flood hazards.[13]Friant Dam Construction (1937–1942)
The Friant Dam, a key component of the Central Valley Project (CVP), was authorized for construction as part of federal efforts to develop water resources in California's Central Valley, with initial funding allocated under the Emergency Relief Appropriation Act of 1935 to support New Deal public works aimed at reducing unemployment during the Great Depression.[14][15] The Rivers and Harbors Act of 1937 formally reauthorized the CVP and directed the U.S. Bureau of Reclamation to undertake the project, emphasizing multipurpose benefits including irrigation storage, flood control, and eventual hydropower.[16][17] Construction activities commenced with site preparation in late 1939, following groundbreaking ceremonies on November 5 attended by over 50,000 people, amid ongoing mobilization of labor from Depression-era relief programs.[18][19] The dam was designed as a concrete gravity structure rising 319 feet high above the streambed with a crest length of 3,488 feet, requiring extensive blasting and excavation to prepare the foundation on the San Joaquin River.[1] Concrete placement began in summer 1940, utilizing high-volume pouring systems capable of 5,500 cubic yards per day, culminating in the placement of the final yard on June 16, 1942, for a total volume of 2,130,480 cubic yards.[18][20] The project employed approximately 1,500 workers earning wages between $0.68 and $1.50 per hour, reflecting prioritized labor absorption from federal relief rolls, though it recorded fatalities including five in 1940 alone due to construction hazards.[18] Upon structural completion in 1942, the dam was positioned to impound waters forming Millerton Lake, which upon initial filling submerged remnants of the historic town of Millerton established in the 1850s.[1][21]Post-Construction Settlement and Expansion
Following the completion of Friant Dam in 1942, water deliveries from Millerton Lake spurred significant agricultural development in the southern San Joaquin Valley, particularly through the construction of associated canals that irrigated previously underutilized arid lands affected by the Dust Bowl era droughts of the 1930s. The Madera Canal, extending 36 miles northward from the dam and completed in 1945 with an initial capacity of 1,000 cubic feet per second, facilitated irrigation for northern districts, enabling the cultivation of crops on marginal soils that had previously supported only limited dry farming.[3] Similarly, the Friant-Kern Canal, stretching 152 miles southward and finalized on June 29, 1951, with substantial capacity for conveyance, supplied water to over 1 million acres of farmland in Fresno, Tulare, and Kern counties, converting dust-prone rangelands into productive orchards, vineyards, and row crop fields.[22][23] This infrastructure-driven expansion shifted local economies from subsistence ranching to large-scale commercial agriculture, with irrigated acreage in the Friant Division growing rapidly in the late 1940s and 1950s as water contracts were activated.[1] Public access to the reservoir also prompted recreational infrastructure growth, culminating in the formal designation of Millerton Lake State Recreation Area. Initially managed by the National Park Service from May 22, 1945, to November 1, 1957, the area transitioned to California State Parks oversight in 1957, establishing it as a dedicated state recreation unit with facilities for boating, fishing, and camping along over 40 miles of shoreline.[24][21] This development supported tourism and outdoor activities without interfering with primary irrigation functions, drawing visitors to the site's historic and natural features while preserving public lands amid rising regional pressures.[8] The influx of reliable water supplies correlated with demographic shifts in the Fresno area, as agricultural mechanization and crop diversification attracted laborers and entrepreneurs, boosting Fresno County's population from approximately 215,000 in 1940 to 277,000 by 1950 and further to 413,000 by 1960.[25] This growth transformed the valley's economy from sporadic, weather-dependent farming to a stable commercial hub, with new settlements and support industries emerging along canal routes to serve expanded operations in fruit, nut, and vegetable production.[14][26]Engineering Features
Friant Dam Specifications
Friant Dam is a concrete gravity structure completed in 1942, standing 319 feet high from foundation to crest with a crest length of 3,488 feet.[1][9] The dam's base width measures 267 feet, providing stability against the hydrostatic pressures of Millerton Lake, which it impounds on the San Joaquin River.[1] Key hydraulic features include a spillway with a capacity of 83,000 cubic feet per second (cfs) at reservoir elevation 578 feet, equipped with floating gates that open automatically based on water levels to manage flood releases.[1][9] Outlet works capacity reaches 16,400 cfs at the same elevation, facilitating controlled downstream flows through penstocks and river outlets.[1]| Specification | Value |
|---|---|
| Type | Concrete gravity |
| Height | 319 feet |
| Crest length | 3,488 feet |
| Base width | 267 feet |
| Spillway capacity | 83,000 cfs (at 578 ft) |
| Outlet works capacity | 16,400 cfs (at 578 ft) |