Bernal Subbasin
Encyclopedia
The Bernal Subbasin is an aquifer
located in the southwestern corner of Livermore Valley Groundwater Basin, Alameda County, California
, USA. All of the groundwater in Livermore Valley
moves toward the Bernal Subbasin, which is bounded on the east by Pleasanton Fault
, on the north by the Park Fault, and on the west by the Calaveras Fault
.(Earth Metrics, 1989) All the streams draining the Livermore Valley merge above the Bernal formation and exit this subbasin and Livermore Amador Valley via the Arroyo de la Laguna
.
Groundwater
occurs throughout the valley floor portion of the Bernal Subbasin under conditions ranging from unconfined to confined. There is no inflow of groundwater across the Pleasanton Fault south of the City of Pleasanton
, because any movement of groundwater in the southern section is essentially parallel to the fault.(Bonnie, 2000)
Groundwater in the Bernal Subbasin typically occurs occurs at an approximate depths of 12 to 30 feet (3.7 to 9.1 meters) below ground surface and flows from east to west.
Aquifer
An aquifer is a wet underground layer of water-bearing permeable rock or unconsolidated materials from which groundwater can be usefully extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology...
located in the southwestern corner of Livermore Valley Groundwater Basin, Alameda County, California
Alameda County, California
Alameda County is a county in the U.S. state of California. It occupies most of the East Bay region of the San Francisco Bay Area. As of the 2010 census it had a population of 1,510,271, making it the 7th most populous county in the state...
, USA. All of the groundwater in Livermore Valley
Livermore Valley
The Livermore Valley AVA is an American Viticultural Area in Alameda County, California, surrounding the city of Livermore in the Tri-Valley region. Both the AVA and the city are named after Robert Livermore, a landowner whose holdings encompassed the valley. The groundwater basin underlying the...
moves toward the Bernal Subbasin, which is bounded on the east by Pleasanton Fault
Pleasanton Fault
The Pleasanton Fault is a seismically active geological structure in Alameda County and Contra Costa County, California , USA.-Relation to hydrological features:...
, on the north by the Park Fault, and on the west by the Calaveras Fault
Calaveras Fault
The Calaveras Fault is a major branch of the San Andreas Fault located in northern California in the San Francisco Bay Area. To the east of the Hayward-Rodgers Creek fault, the Calaveras fault extends 123 km, splaying from the San Andreas fault near Hollister and terminating at Danville at its...
.(Earth Metrics, 1989) All the streams draining the Livermore Valley merge above the Bernal formation and exit this subbasin and Livermore Amador Valley via the Arroyo de la Laguna
Arroyo de la Laguna
Arroyo de la Laguna is a southward-flowing stream in Alameda County, California, USA which originates at the confluences of South San Ramon Creek and Arroyo Mocho. The Arroyo de la Laguna is fed by tributaries in the Amador Valley and certain eastern slope drainages of the Diablo Range; these...
.
Groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
occurs throughout the valley floor portion of the Bernal Subbasin under conditions ranging from unconfined to confined. There is no inflow of groundwater across the Pleasanton Fault south of the City of Pleasanton
Pleasanton, California
Pleasanton is a city in Alameda County, California, incorporated in 1894. It is a suburb in the San Francisco Bay Area located about east of Oakland, and west of Livermore. The population was 70,285 at the 2010 census. In 2005 and 2007, Pleasanton was ranked the wealthiest middle-sized city in...
, because any movement of groundwater in the southern section is essentially parallel to the fault.(Bonnie, 2000)
Groundwater in the Bernal Subbasin typically occurs occurs at an approximate depths of 12 to 30 feet (3.7 to 9.1 meters) below ground surface and flows from east to west.
See also
- Arroyo del ValleArroyo del ValleArroyo del Valle or Arroyo Valle is a westward-flowing stream in Alameda County and Santa Clara County, California, USA, that is tributary to Arroyo de la Laguna which in turn flows into Alameda Creek. The stream drains much of the southern portion of the city of Livermore, and it also flows...
- westward flowing stream in Livermore and Pleasanton. - Mocho SubbasinMocho SubbasinThe Mocho Subbasin is the largest of the groundwater subbasins in the Livermore Valley watershed. This subbasin is bounded to the west by the Livermore Fault Zone and to the east by the Tesla Fault...
- groundwater subbasin in the Livermore Valley. - Niles ConeNiles ConeThe Niles Cone is a groundwater basin in Alameda County, California, USA which is the source of drinking water for a sizeable human urban population in the East Bay. The land area corresponding to this groundwater basin is approximately 103 square miles; the Niles Cone Basin is bounded on the...
- groundwater basin in Alameda County.