The Rio San Bernardino, or San Bernardino River, begins in extreme southeastern Cochise County, Arizona, and is a tributary of the

Bavispe River The Rio Bavispe or Bavispe River is a river in Mexico which flows briefly north then mainly south by southwest until it joins with the Aros River to become the Yaqui River, eventually joining the Gulf of California. History Historically, the Rio ...

, in Sonora,

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

Watershed

The Rio San Bernardino has two major tributaries, the Rio de Agua Prieta and the Arroyo Cajón Bonito. The river's headwaters are in extreme southeastern Cochise County, Arizona as Black Draw. From here the Rio San Bernardino flows south, crossing into Mexico east of

Douglas, Arizona Douglas is a city in Cochise County, Arizona, United States that lies in the north-west to south-east running Sulpher Springs Valley. Douglas has a border crossing with Mexico at Agua Prieta and a history of mining. The population was 16,531 i ...

. In northern Sonora, the Cajón Bonito River joins the San Bernardino River in the

San Bernardino Valley The San Bernardino Valley ( es, Valle de San Bernardino) is a valley in Southern California located at the south base of the Transverse Ranges. It is bordered on the north by the eastern San Gabriel Mountains and the San Bernardino Mountains; ...

after draining the Sierra San Luis and northern end of the

Sierra Madre Occidental The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs northwest–southeast through northwestern and western Mexico, and along the Gulf of California. The Sierra Madre is part of the American ...

. Next the Rio San Bernardino is joined by the Agua Prieta River which also begins in Cochise County, crossing south as Whitewater Draw into Mexico at

Douglas Douglas may refer to: People * Douglas (given name) * Douglas (surname) Animals * Douglas (parrot), macaw that starred as the parrot ''Rosalinda'' in Pippi Longstocking *Douglas the camel, a camel in the Confederate Army in the American Civi ...

and

Agua Prieta Agua Prieta (English: ''Dark Water'', Opata: ''Bachicuy'') is a town in Agua Prieta Municipality in the northeastern corner of the Mexican state of Sonora. It stands on the Mexico–U.S. border, adjacent to the town of Douglas, Arizona. The mu ...

. The Agua Prieta River flows south and east to join the Rio San Bernardino, shortly after the Rio Agua Prieta has its confluence with the Rio Fronteras, the latter flowing north from near Nacozari de Garcia, Sonora. The San Bernardino River joins the

at Morelos, Sonora at the northern end of the Sierra del Tigre. The Bavispe River flows south by southwest to the

Yaqui River The Yaqui River (Río Yaqui in Spanish) (Hiak Vatwe in the Yaqui or Yoreme language) is a river in the state of Sonora in northwestern Mexico. It was formerly known as the Rio del Norte. Being the largest river system in the state of Sonora, th ...

and eventually to the

Gulf of California The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja C ...

at Ciudad Obregon, Sonora.

Ecology

North American beaver The North American beaver (''Castor canadensis'') is one of two extant beaver species, along with the Eurasian beaver (''Castor fiber''). It is native to North America and introduced in South America ( Patagonia) and Europe (primarily Finland ...

(''Castor canadensis'') were documented by Leopold in 1977 in northern Mexico, and a 2000 survey found five breeding pairs of beavers on the Cajón Bonito River mostly in remote ranches without livestock. The authors of the latter study reported that local ranchers kill beavers because they fear felled trees will block roads. However, beavers are considered keystone species and ecosystem engineers, as their dams raise the water table and turn seasonal stretches of streams into perennial reaches, producing highly beneficial impacts on species abundance and diversity in the riparian zone. Beavers were also documented by Hendrickson et al. in 1978 on the Cajón Bonito.

References

{{authority control Rivers of Arizona Rivers of Cochise County, Arizona Rivers of Sonora

Watershed

Ecology

See also

References