San Jacinto River (California)

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San Jacinto River
San Jacinto River.jpg
The mouth of the San Jacinto on Lake Elsinore, viewed from California State Route 74 (the Ortega Highway) on the southwest side of the lake
Country United States
State California
Region Riverside County
Part of Santa Ana River basin
 - left South Fork San Jacinto River
 - right North Fork San Jacinto River
Cities Hemet, San Jacinto, Perris, Lake Elsinore
Source San Jacinto Mountains
 - location San Bernardino National Forest, Riverside County
 - elevation 2,100 ft (640 m)
 - coordinates 33°43′52″N 116°48′36″W / 33.73111°N 116.81000°W / 33.73111; -116.81000 [1]
Mouth Lake Elsinore
 - location Lake Elsinore, at the mouth of Railroad Canyon, northwest of the Sedco Hills and west of the Tuscany Hills of the Temescal Mountains., Riverside County
 - elevation 1,243 ft (379 m)
 - coordinates 33°38′45.06″N 117°18′53.42″W / 33.6458500°N 117.3148389°W / 33.6458500; -117.3148389Coordinates: 33°38′45.06″N 117°18′53.42″W / 33.6458500°N 117.3148389°W / 33.6458500; -117.3148389
Length 42 mi (68 km), Northwest then southwest
Basin 780 sq mi (2,020 km2) [2]
 - average 16.4 cu ft/s (0 m3/s) [3]
 - max 16,000 cu ft/s (453 m3/s)
 - min 0 cu ft/s (0 m3/s)
Map of the Santa Ana River watershed with the San Jacinto subbasin highlighted in darker green.

The San Jacinto River is a 42-mile-long (68 km)[4] river in Riverside County, California. The river's headwaters are in San Bernardino National Forest, but the lower portion of the 765-square-mile (1,980 km2) watershed is urban and agricultural land.

The river is formed at the west base of the San Jacinto Mountains by the confluence of its North and South forks. The South Fork flows from Lake Hemet, which holds 14,000 acre feet (17,000,000 m3) of water. Hemet Dam was built in 1895 to supply water to the city of Hemet. Downstream of the dam, the South Fork joins the North Fork east of the town of Valle Vista near Highway 74, and the main stem of the San Jacinto River continues northwest until it discharges into Mystic Lake, a couple of miles east of Lake Perris. Overflow from the river then flows southwest, passing under Ramona Expressway and Interstate 215, and through Railroad Canyon to Railroad Canyon Reservoir, also called Canyon Lake, which has a capacity of 11,900 acre feet (14,700,000 m3). Downstream of Railroad Canyon Dam, the river continues flowing roughly west southwest through the canyon through the Temescal Mountains for about 3 miles (4.8 km) until it drains into Lake Elsinore. The lake has very little outflow, but in rare cases it has overflowed into Temescal Creek, a tributary of the Santa Ana River, that flows northwest to that river in Corona, California.

As an endorheic watershed that is contiguous with other Great Basin watersheds, the western side of the San Jacinto Basin is a portion of the Great Basin Divide.

List of tributaries of the San Jacinto River[edit]


  1. ^ "San Jacinto River". Geographic Names Information System. United States Geological Survey. 1981-01-19. Retrieved 2010-11-22. 
  2. ^ "San Jacinto River Watershed: Geographic Setting". Lake Elsinore and Canyon Lake Task Force. Santa Ana Watershed Project Authority. Retrieved 2010-11-22. 
  3. ^ "USGS Gage #11070500 on the San Jacinto River near Elsinore, CA" (PDF). National Water Information System. U.S. Geological Survey. 1916–2009. Retrieved 2010-11-22. 
  4. ^ U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map, accessed March 16, 2011