San Joaquin
San Joaquin is a mapped river in the YearMaps hydrographic index. River courses organise settlement, agriculture and frontier-making more durably than any political boundary, and this reach is indexed against the dams, lakes and cities within its catchment.
- Feature Class
- River
- Coordinates
- 37.09°, -120.55°
About San Joaquin
The San Joaquin River ( SAN whah-KEEN; Spanish: Río San Joaquín [ˈri.o saŋ xoaˈkin]) is the longest river of Central California. The 366-mile (589 km) 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 Francisco Bay, and the Pacific Ocean. An important source of irrigation water as well as a wildlife corridor, the San Joaquin is among the most heavily dammed and diverted of California's rivers.
People have inhabited the San Joaquin Valley for more than 8,000 years, and it was one of the major population centers of pre-Columbian California. Starting in the late 18th century, successive waves of explorers then settlers, mainly Spanish and American, emigrated to the San Joaquin basin. When Spain colonized the area, they sent soldiers from Mexico, who were usually of mixed native Mexican and Spanish birth, led by Spanish officers. Franciscan missionaries from Spain came with expeditions to evangelize the natives by teaching them about the Catholic faith.
Encyclopedic summary adapted from Wikipedia: San Joaquin River (CC BY-SA 4.0).
San Joaquin in Depth
Course
The river's source is located in the Ansel Adams Wilderness, in the south-central Sierra Nevada at the confluence of three major affluents: the Middle Fork, which rises from Thousand Island Lake at almost 10,000 ft (3,000 m) above sea level, meets the North Fork, which starts 1.8 mi (2.9 km) southeast of Mount Lyell, and the South Fork, which begins at Martha Lake in Kings Canyon National Park and flows through Florence Lake, joins a short distance downstream. The Middle Fork is considered the largest of the three forks. From the mountainous alpine headwaters, the San Joaquin flows generally south into the foothills of the Sierra, passing through four hydroelectric dams.
History
Archaeological finds near the southern end of the San Joaquin Valley suggested that humans first arrived in the region as early as 12,000 but no later than 5,000 years ago. The two major ethnic groups were the Miwok people, who inhabited the northern end of the San Joaquin Valley and the Sacramento-San Joaquin Delta region, and the Yokuts tribes, scattered around the more arid southern portion of the basin. During these pre-European times, the San Joaquin River flowed through rich grasslands and sprawling marshes, flooding every few years and transforming much of the valley into lakes. At the southern end of the valley lay the vast Tulare Lake, formerly the largest freshwater lake in the western United States, which connected with the San Joaquin through a series of marshes and sloughs.
Ecology and environment
Hundreds of years ago, the San Joaquin flowed freely through a grass and marsh-dominated region variously known as the "California prairie", "California annual grassland", or "Central Valley grasslands". It is widely believed that the dominant grass species throughout the San Joaquin River valley and Tulare Basin, as well as the Sacramento Valley, the Sierra foothills and Coast Ranges, was Nassella pulchra, a type of bunchgrass more commonly known as purple needlegrass. Today, this vegetation community exists only in isolated pockets because of development of the valley for agriculture, and in much of the remnant open areas where it once thrived, now grows introduced flora such as annual rye and wild oat.
Geology
In a geologic context, the San Joaquin River can be divided into two major segments. The upper 97 mi (156 km) above Friant Dam in the Sierra is characterized as a steep-gradient, rocky mountain stream. Over millions of years, the upper San Joaquin, as well as the upper reaches of most of its tributaries, have eroded enormous amounts of rock and sediment from the mountains.
Sections adapted from Wikipedia: San Joaquin River (CC BY-SA 4.0).
San Joaquin: Key Facts
| Length | 564 km |
|---|---|
| Drainage basin | 40,400 km² |
| Source | Thousand Island Lake |
| Mouth | Sacramento River |
| Drainage system | San Joaquin River basin |
| Tributaries | Stanislaus River, Tuolumne River, Merced River, Mokelumne River, Calaveras River, Chowchilla River, Fresno River, Garzas Creek |
Facts from Wikidata Q751347 (CC0).
Major River Dossiers
Hand-written studies of the great river systems of history.
Connected Reaches
Nearby watercourses in the same drainage network.
Water Bodies in the Catchment
Settlements Along the Reach
Hydraulic Infrastructure Nearby
Surrounding Terrain
San Joaquin: Quick Answers
- Where is San Joaquin?
- San Joaquin is located in United States, at 37.0940° N, 120.5508° W.
- Are there dams on the San Joaquin?
- No dam on the San Joaquin is recorded in the YearMaps dam index, which covers major structures only.