Arroyo Mocho is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data
The National Map
, accessed March 15, 2011 stream which originates in the far northeastern corner of

Santa Clara County Santa Clara County, officially the County of Santa Clara, is the sixth-most populous county in the U.S. state of California, with a population of 1,936,259, as of the 2020 census. Santa Clara County and neighboring San Benito County together f ...

and flows northwesterly into eastern

Alameda County, California Alameda County ( ) is a county located in the U.S. state of California. As of the 2020 census, the population was 1,682,353, making it the 7th-most populous county in the state and 21st most populous nationally. The county seat is Oakland. Alam ...

. After traversing the cities of Livermore and Pleasanton it joins South San Ramon Creek to become Arroyo de la Laguna, which in turn flows to Alameda Creek and thence to San Francisco Bay.

History

Arroyo Mocho means "cutoff creek". Erwin G. Gudde's ''California Place Names'' says it got the name because it historically had no outlet but dissipated into the ground after spreading out into many smaller streams between Livermore and Pleasanton. As early as 1852 it was also called Mocho Creek. Frank Latta, in his book on

Joaquin Murrieta Joaquin Murrieta Carrillo (sometimes spelled Murieta or Murietta) (1829 – July 25, 1853), also called the Robin Hood of the West or the Robin Hood of El Dorado, was a Mexican-American figure of disputed historicity. The novel '' The Life and A ...

, says it got its name from the nickname of the man who ran the Murrietta gang's water stations and holding corrals in this area along La Vereda del Monte, the route of their drives of captured mustangs and stolen horses to the south. These stations were on the arroyo near Mud Springs and at Valle de Mocho, what is now known as Blackbird Valley, near the source of the arroyo, just south of Mount Mocho, which was also named for this man, known as "Mocho" (meaning lopped off or short) for his diminutive stature.Frank F. Latta, JOAQUIN MURRIETA AND HIS HORSE GANGS, Bear State Books, Santa Cruz, California. 1980.

Watershed and course

The Arroyo Mocho watershed drains . Arroyo Mocho originates on the western slope of Mount Mocho in the northeast corner of

and flows west to Mines Road which it follows northwest into

Alameda County Alameda County ( ) is a county located in the U.S. state of California. As of the 2020 census, the population was 1,682,353, making it the 7th-most populous county in the state and 21st most populous nationally. The county seat is Oakland. Alam ...

. It passes Sweet Springs, a magnesia spring known for its sweet taste. Although historically it sank into the area between Livermore and Pleasanton now the site of multiple gravel pits, there is an engineered channel connecting it to Arroyo de la Laguna. The underlying aquifer is the

Mocho Subbasin The Mocho Subbasin is the largest of the groundwater subbasins in the Livermore Valley watershed in Northern California. This subbasin is bounded to the west by the Livermore Fault Zone and to the east by the Tesla Fault. Some groundwater fl ...

, whose eastern boundary is the Tesla Fault. Some groundwater flow occurs across this fault boundary, but flows are discontinuous below a depth of across the Tesla Fault and south of the Arroyo Mocho channel across the Livermore Fault.

Ecology

Arroyo Mocho has a self-sustaining rainbow trout (''Oncorhynchus mykiss'') population, and trout can migrate to the lower watershed from Alameda Creek.

References

{{reflist

External links

Arroyo Mocho Watershed Map at Oakland Museum
Rivers of Alameda County, California Tributaries of Alameda Creek Diablo Range Livermore Valley Geography of Pleasanton, California Livermore, California Rivers of Northern California La Vereda del Monte

History

Watershed and course

Ecology

See also

References

External links