San Juan Creek

San Juan Creek
San Juan River[1]
Hikers ford San Juan Creek below the hot springs, February 2008.
Map of the San Juan Creek watershed
EtymologyNamed for Mission San Juan Capistrano by Spanish conquistadors in the 1700s.
Location
CountryUnited States
StateCalifornia
RegionOrange County, Riverside County
Physical characteristics
Sourcehead of San Juan Canyon, at the confluence of Morrell Canyon Creek with Bear Canyon Creek, Santa Ana Mountains
 • coordinates33°36′49″N 117°26′07″W / 33.61361°N 117.43528°W / 33.61361; -117.43528
 • elevation1,690 ft (520 m)
MouthSan Juan Lagoon, Doheny State Beach, Dana Point
 • coordinates
33°27′42″N 117°41′01″W / 33.46167°N 117.68361°W / 33.46167; -117.68361
 • elevation
0 ft (0 m)
Length29 mi (47 km)
Basin size133.9 sq mi (347 km2)
Discharge 
 • locationSan Juan Capistrano[2]
 • average26.1 cu ft/s (0.74 m3/s)[3]
 • minimum0 cu ft/s (0 m3/s)
 • maximum14,700 cu ft/s (420 m3/s)
Basin features
Tributaries 
 • leftLucas Canyon Creek, Verdugo Canyon Creek, Trampas Canyon Creek
 • rightLion Canyon Creek, Hot Springs Canyon Creek, Cold Spring Canyon Creek, Bell Canyon Creek, Cañada Gobernadora, Cañada Chiquita, Horno Creek, Arroyo Trabuco

San Juan Creek, also called the San Juan River,[1] is a 29-mile (47 km) long stream in Orange and Riverside Counties, draining a watershed of 133.9 square miles (347 km2).[4][5] Its mainstem begins in the southern Santa Ana Mountains in the Cleveland National Forest. It winds west and south through San Juan Canyon, and is joined by Arroyo Trabuco as it passes through San Juan Capistrano. It flows into the Pacific Ocean at Doheny State Beach. State Route 74, the Ortega Highway, crosses the Santa Ana Mountains via San Juan Canyon.

Before Spanish colonization in the 1770s, the San Juan Creek watershed was inhabited by the Acjachemen or Juañeno Native Americans. The Juañeno were named by Spanish missionaries who built Mission San Juan Capistrano on the banks of a stream they named San Juan Creek. The watershed was used mainly for agriculture and ranching until the 1950s when residential suburban development began on a large scale. Since then, development has continued to encroach on floodplains of local streams. Flooding in the 20th and 21st centuries has caused considerable property damage in the San Juan watershed.

The San Juan watershed is home to sixteen major native plant communities and hundreds of animal species. However, the watershed is projected to be 48 percent urbanized by 2050. In addition, urban runoff has changed flow patterns in San Juan Creek and introduced pollutants to the river system. Although the main stem of San Juan Creek does not have any major water diversions or dams, some of its tributaries, including Trabuco and Oso Creeks, have been channelized or otherwise heavily modified by urbanization.

  1. ^ a b "San Juan Creek". Geographic Names Information System. United States Geological Survey. Retrieved 2008-02-21.
  2. ^ "USGS Gage #11046550 on San Juan Creek at San Juan Capistrano, CA". National Water Information System. U.S. Geological Survey. 1969–1985. Retrieved 2015-11-18.
  3. ^ "USGS Gage #11046550 on San Juan Creek at San Juan Capistrano, CA". National Water Information System. U.S. Geological Survey. 1969–1985. Retrieved 2015-11-18.
  4. ^ 7.5 Minute Quadrangle Map, U.S. Geological Survey, San Juan Capistrano, 1968, photorevised 1981
  5. ^ "Introduction to San Juan Creek Watershed". Watershed and Coastal Resources Division of Orange County. www.ocwatersheds.com. Archived from the original on 2007-10-13.