Cottonwood Creek (San Diego County)

Cottonwood Creek is a major stream, about 36 miles (58 km) long,[1] in southern San Diego County, California. It is part of the Tijuana River drainage basin.

Cottonwood Creek
Location of Cottonwood Creek in California
Location
Country	United States
State	California
Physical characteristics
Source	Laguna Mountains
⁃ location	Cleveland National Forest
⁃ coordinates	32°49′56″N 116°27′57″W[1]
⁃ elevation	5,406 ft (1,648 m)
Mouth	Rio Alamar
⁃ location	About 15 mi (24 km) east of Tijuana
⁃ coordinates	32°34′02″N 116°45′55″W[1]
⁃ elevation	558 ft (170 m)
Length	36 mi (58 km)[1]
Basin size	310 sq mi (800 km2)[2]
Discharge
⁃ location	near Dulzura[2]
⁃ average	15.2 cu ft/s (0.43 m3/s)[2]
⁃ minimum	0 cu ft/s (0 m3/s)
⁃ maximum	11,700 cu ft/s (330 m3/s)

The creek begins in the Laguna Mountains, in the Cleveland National Forest near Pine Valley. It flows south through the Cottonwood Valley into Lake Morena, which is formed by Morena Dam. Below the dam it turns west, flowing through a narrow gorge to Barrett Lake, created by Barrett Dam. From there it turns south, passing Barrett Junction, before joining with Tecate Creek to form the Rio Alamar, a tributary of the Tijuana River. The confluence of the two streams is located only about 200 yards (180 m) north of the United States–Mexico border. Both Tecate Creek and the Alamar are located mostly in Mexico.[3]

Map showing the locations of Cottonwood Creek, Tecate Creek and Rio Alamar

Both Morena and Barrett Reservoirs are part of the San Diego, California municipal water supply system. Water travels from Cottonwood Creek via the Dulzura Conduit to Lower Otay Reservoir. Cottonwood Creek provides only a small fraction of San Diego's water supply, which mainly depends on imported Colorado River water.[4]