The South Fork San Joaquin River is the largest

headwater The headwaters of a river or stream is the farthest place in that river or stream from its estuary or downstream confluence with another river, as measured along the course of the river. It is also known as a river's source. Definition The ...

of the

San Joaquin River The San Joaquin River (; es, Río San Joaquín) 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 Suis ...

in central

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. About long, it drains an area of the high

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...

about northeast of

Fresno Fresno () is a major city in the San Joaquin Valley of California, United States. It is the county seat of Fresno County and the largest city in the greater Central Valley region. It covers about and had a population of 542,107 in 2020, maki ...

Course

The South Fork begins at Martha Lake, above sea level, near

Mount Goddard Mount Goddard is a mountain of California's Sierra Nevada, in the north section of Kings Canyon National Park Kings Canyon National Park is an American national park in the southern Sierra Nevada, in Fresno and Tulare Counties, California. ...

in the northern section of

Kings Canyon National Park Kings Canyon National Park is an American national park in the southern Sierra Nevada, in Fresno and Tulare Counties, California. Originally established in 1890 as General Grant National Park, the park was greatly expanded and renamed to Kings ...

Fresno County Fresno County (), officially the County of Fresno, is a county located in the central portion of the U.S. state of California. As of the 2020 Census, the population was 1,008,654. The county seat is Fresno, the fifth-most populous city in Cali ...

. It flows northwest through the narrow Goddard Canyon, receiving Evolution Creek from the east, then leaves the park at the confluence with Piute Creek from the north, entering the

Sierra National Forest Sierra National Forest is a U.S. national forest located on the western slope of central Sierra Nevada in Central California and bounded on the northwest by Yosemite National Park and the south by Kings Canyon National Park. The forest is kno ...

. It then flows west, through Blayney Meadows, into Florence Lake, impounded by

Florence Lake Dam Florence Lake Dam is a concrete multiple-arch dam on the South Fork of the San Joaquin River, in Fresno County, California in the United States. The high dam was designed by John S. Eastwood and completed in 1926 (two years after Eastwood's dea ...

. Below the dam it flows briefly north, receiving Bear Creek, before turning west again, through a wider valley past Mono Hot Springs then receiving its main tributary, Mono Creek, from the north. The South Fork enters the

Ansel Adams Wilderness The Ansel Adams Wilderness is a wilderness area in the Sierra Nevada of California, United States. The wilderness spans ; 33.9% of the territory lies in the Inyo National Forest, 65.8% is in the Sierra National Forest, and the remaining 0.3% cover ...

as it turns northwest, receiving Four Forks and Rube Creeks before crossing into

Madera County Madera County (), officially the County of Madera, is a county at the geographic center of the U.S. state of California. As of the 2020 census, the population was 156,255. The county seat is Madera. Madera County comprises the Madera, CA Metr ...

. Soon after entering Madera County, it joins the San Joaquin River, in a deep granite canyon below Balloon Dome at San Joaquin

river mile A river mile is a measure of distance in miles along a river from its mouth. River mile numbers begin at zero and increase further upstream. The corresponding metric unit using kilometers is the river kilometer. They are analogous to vehicle road ...

334 (km 537), a short distance above

Mammoth Pool Reservoir Mammoth Pool Reservoir is a reservoir on the San Joaquin River in the Sierra Nevada (U.S.), Sierra Nevada, within the Sierra National Forest in California. It creates the border between Fresno County, California, Fresno County and Madera County, ...

River modifications

The Florence Lake Dam, as well as Vermillion Valley Dam on Mono Creek which forms Lake Thomas A. Edison, are both part of the

Big Creek Hydroelectric Project The Big Creek Hydroelectric Project is an extensive hydroelectric power scheme on the upper San Joaquin River system, in the Sierra Nevada of central California. The project is owned and operated by Southern California Edison (SCE). The use and reu ...

operated by

Southern California Edison Southern California Edison (or SCE Corp), the largest subsidiary of Edison International, is the primary electricity supply company for much of Southern California. It provides 15 million people with electricity across a service territory of app ...

to provide electricity to

Los Angeles Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...

. In 1925, water was first diverted from the South Fork via the Ward Tunnel into

Huntington Lake Huntington Lake is a reservoir in Fresno County, California on Big Creek, located in the Sierra Nevada at an elevation of 7000 ft. The lake receives water from Southern California Edison's Big Creek Hydroelectric Project, as well as the ...

. The concrete multiple-arch Florence Lake dam was completed in 1926 to ensure a year-round water supply for the tunnel. The larger, earthen Vermillion Valley Dam was built much later, in 1953. The dams divert a considerable amount of water from the South Fork for power generation, especially during the late summer and fall when water flows are already naturally low.

Recreation

The South Fork between Piute Creek and Florence Lake has a wide variety of difficulty levels for boating, ranging from a gentle, smooth meandering stream in the Blayney Meadows section to continuous Class VI to V+ whitewater in the last above Florence Lake, as well as a number of waterfalls that must be portaged. Below the Florence Lake Dam river flows are less reliable due to water diversions, except in years of particularly heavy snowmelt.

References

{{John Muir Wilderness Rivers of Fresno County, California Rivers of Madera County, California Tributaries of the San Joaquin River

Course

River modifications

Recreation

See also

References