The Sweetwater River is a long stream in San Diego County, California.
From its headwaters high in the Cuyamaca Mountains, the river flows generally southwest, first through rugged hinterlands but then into the urban areas surrounding its mouth at San Diego Bay. Its drainage basin covers more than , all of it within San Diego County. Towns on the river include Descanso, La Presa and Chula Vista.
The term "Sweetwater" is a name often given to freshwater which tastes good in regions where much of the water is bitter to the taste. The Spanish called the river "Agua Dulce", a name they applied to good clear water anywhere they lived.
Course
The river rises as an intermittent trickle flowing out of Upper Green Valley, deep in the semi-arid Cuyamaca Mountains near Stonewall Peak. It flows south-southwest, receiving Harper Creek from the left and Stonewall Creek from the right, then coursing through narrow valleys and passing the small town of Descanso. As the river enters the Cleveland National Forest, it cuts through a steep and spectacular rocky gorge and crosses under a high bridge of Interstate 8. Shortly after leaving the national forest, it flows into Loveland Reservoir, formed by Loveland Dam, the first of two major dams along the Sweetwater.
Continuing westwards, it receives the North Fork from the right, travels by the city of Rancho San Diego and passes through the Rancho San Diego Golf Course. The river then enters Sweetwater Reservoir, which is formed by the Sweetwater Dam. Below the dam, the Sweetwater flows through Sweetwater Regional Park in a generally suburban area, passing the unincorporated town of Bonita. Bending northwest, the river enters a flood control channel and passes between National City and Chula Vista. California State Route 54 straddles the river, with eastbound lanes to the south and westbound lanes to the north, for a few miles between I-5 and I-805. The tidal portion of the river, which starts roughly here, is called the Sweetwater Marsh. The river empties into San Diego Bay about southeast of downtown San Diego.
Watershed
This river drains a long, narrow basin of in extreme southern California, with its mouth less than north of the United States-Mexico border. Much of the river's watershed is mountainous, and the highest point is above sea level at Stonewall Peak in the Cuyamacas Mountains. A large portion of the drainage lies within the Cleveland National Forest, but few trees are actually supported by the arid climate. The Sweetwater is the largest river flowing into San Diego Bay.
Most of the drainage, nearly 64 percent, comprises wilderness or designated parks and open space. However, approximately 30% is urban development and part of the San Diego metro area. Native American reservations also occupy part of the land. The watershed has a human population of over 300,000; mostly residing in the residential cities of Chula Vista, National City, and others such as La Presa, Bonita and Rancho San Diego, all in the less rugged western portion of the basin.
The eastern drainage divide of the Sweetwater watershed lies on the main divide of the Cuyamacas, which also separates streams of the Pacific slope from streams draining to the endorheic basin of the Salton Sea farther to the east. To the north, the Sweetwater basin shares borders with those of the San Diego River and the smaller streams that drain portions of National City and San Diego. On the south, it is bordered by the Otay River and Tijuana River drainages – specifically for the Tijuana, the subwatershed of Cottonwood Creek, the river's main tributary in the U.S.
Before reaching San Diego Bay, the river flows into Sweetwater Marsh, a part of the San Diego National Wildlife Refuge. Adjacent to the marsh is the Chula Vista Nature Center hosting nature walks and an aviary with native birds such as burrowing owls, egrets and herons.
History
In pre-American times, the Sweetwater River was a small but year-round stream, lined on both banks by extensive riparian forests, marshes and floodplains. It is believed that humans first arrived in the San Diego Bay area between 20,000 and 30,000 years ago. The Kumeyaay called this river Ah-ha-ooo-mulk, meaning "water sweet". The villages they had included Sekwan and Hamacha on the middle portion of the stream; Amotaretuwe to the north, and Ekwiamak in the headwaters portion.