| Cottonwood Creek | |
| Map: | Tijuana River Basin.svg |
| Map Size: | 250 |
| Pushpin Map: | USA California |
| Pushpin Map Size: | 250 |
| Pushpin Map Caption: | Location of Cottonwood Creek in California |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | California |
| Length: | 36miles |
| Discharge1 Location: | near Dulzura |
| Discharge1 Min: | 0cuft/s |
| Discharge1 Avg: | 15.2cuft/s |
| Discharge1 Max: | 11700cuft/s |
| Source1: | Laguna Mountains |
| Source1 Location: | Cleveland National Forest |
| Source1 Coordinates: | 32.8322°N -116.4658°W[1] |
| Source1 Elevation: | 5406feet |
| Mouth: | Rio Alamar |
| Mouth Location: | About 15miles east of Tijuana |
| Mouth Coordinates: | 32.5672°N -116.7653°W |
| Mouth Elevation: | 558feet |
| Basin Size: | 310sqmi[2] |
Cottonwood Creek is a major stream, about 36miles long,[1] in southern San Diego County, California. It is part of the Tijuana River drainage basin.
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 200yd north of the United States–Mexico border. Both Tecate Creek and the Alamar are located mostly in Mexico.[3]
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]