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 flow occurs across these fault boundaries, but flows are discontinuous below a depth of fifty feet across the Tesla Fault and south of the Arroyo Mocho channel across the Livermore Fault.Surface watercourses in this unit include Arroyo Valle and Arroyo Seco.
To the north, the Tiago Macheira Subbasin contacts the Tassajara Formation, with which no groundwater exchange occurs. Groundwater flow in the subbasin is generally from southeast toward the northwest or north, corresponding to the slope of the regional terrain and water table surface. Uncontained shallow groundwater occurs within 25 feet (8 m) of the surface, while deeper confined water has levels that occur at various depths from 75 feet (20 m) to 150 feet (50 m) below the surface.
Water quality in the subbasin is generally fair with regard to sodium bicarbonate and magnesium bicarbonate,However, the trend in adverse water quality due to total dissolved solids indicates unpotable conditions may exist as early as 2020 due to overpopulation of the Livermore-Amador Valley by humans and associated discharge of salts to the groundwater.
This subbasin is in the vicinity of the seismically active Greenville Fault associated with the Diablo Range. In fact the name of the second segment of the Greenville Fault (starting from north to south) is the Arroyo Mocho Segment.The Arroyo Mocho Segment is generally considered to be more well developed and not as youthful as traces delineating the Marsh Creek-Greenville Segment, for example.
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 valley is the Livermore Basin, the largest sub-unit of which is the Mocho Subbasin. The Livermore Basin is one of five aquifers in the San Francisco Bay Area that supply most of the metropolitan Bay Area population. The entire Livermore Basin aquifer faces a concern over elevated total dissolved solids by the year 2020 due to an expanding human population leading to higher rates of return water flows to the aquifer containing certain salts.
Murray Township was a township located in what is now the Livermore Valley portion of Alameda County, California, including the present day cities of Livermore, Dublin, and Pleasanton, and the census-designated place of Sunol.
The Clayton-Marsh Creek-Greenville Fault is a fault located in the eastern San Francisco Bay Area of California, in Alameda County and Contra Costa County. It is part of the somewhat parallel system of faults that are secondary to the San Andreas Fault.
Arroyo Seco is an 11.7-mile-long (18.8 km) watercourse in Alameda County, California, that traverses through the city of Livermore. Arroyo Seco means "dry stream" in Spanish. Arroyo Seco lies above the Arroyo Seco watershed, which includes the eastern part of the city of Livermore and also the Sandia National Laboratory. The Mocho Subbasin is the largest of the 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. Some groundwater flow occurs across these fault boundaries, but flows are discontinuous below a depth of 50 feet (15 m) across the Tesla Fault and south of the Arroyo Mocho channel across the Livermore Fault. A number of threatened and endangered species occur in this watershed.
The Tesla Fault can be found in the northeastern Diablo Range, California. This fault is only semi-active.
Arroyo Mocho is a 34.7-mile-long (55.8 km) stream which originates in the far northeastern corner of Santa Clara County and flows northwesterly into eastern Alameda County, California. 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.
Arroyo de la Laguna is a 7.5-mile-long (12.1 km) southward-flowing stream in Alameda County, California, United States 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 tributaries include Arroyo Valle and Sinbad Creek. Arroyo del la Laguna is the major tributary to Alameda Creek which in turn flows into the San Francisco Bay.
South San Ramon Creek is a 9.3-mile-long (15.0 km) southward-flowing stream in Alameda County and southern Contra Costa County, in the East Bay region of northern California.
The Tassajara Formation is a geologic unit within the Livermore Valley of Northern California, United States. The formation surfaces only in the northern upland parts of the Livermore Valley and underlie the central part of the valley floor at a depth ranging from 250 feet (80 m) to 700 feet (200 m). The Tassajara Formation consists of sediments ranging from brown to gray mudstone, andesitic sandstone, conglomerate, and minor bentonitic and pumiceous tuff. In the northern San Ramon area, the Tassajara Formation underlies Quaternary valley fill material.
The Bishop Subbasin is an aquifer that resides between two subsurface structures of the Tassajara Formation in the northern extremity of the Amador Valley, California. This aquifer is a sub-unit of the Livermore-Amador Groundwater Basin. The Bishop Subbasin is associated with the locale of San Ramon, California in Contra Costa County. The Bishop Subbasin along with the Mocho Subbasin is one of the aquifers in the Livermore Valley that has been studied the most heavily for benefits of injection of reclaimed reverse osmosis waters.
The Turlock Basin is a sub-basin of the San Joaquin Valley groundwater basin which occupies approximately 13,700 total square miles, making it the largest groundwater basin in California. The Turlock Basin makes up 542 square miles of this total. This aquifer is located within Merced and Stanislaus counties in the Central Valley bounded by the Tuolumne River to the north, the Merced River to the south and San Joaquin River to the west. The Sierra Nevada foothills bound the sub-basin to the east. Groundwater in the San Joaquin Valley occurs mostly in younger alluvial material. The Turlock Basin lies to the east of the city of Turlock. Groundwater in the Turlock Basin occurs in older alluvial deposits. Large portions of the San Joaquin Basin have experienced overdraft of water and infiltration of agricultural water pollutants, resulting in poor water quality.
The Bernal Subbasin is an aquifer located in the southwestern corner of Livermore Valley Groundwater Basin, Alameda County, California, United States. 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.
The Pleasanton Fault is a seismically active geological structure in Alameda County and Contra Costa County, California, USA.
San Juan Creek, also called the San Juan River, is a 29-mile (47 km) long stream in Orange County, California, draining a watershed of 133.9 square miles (347 km2). Its mainstem begins in the southern Santa Ana Mountains in the Cleveland National Forest. It winds west and south through San Juan Canyon, and is joined by Arroyo Trabuco as it passes through San Juan Capistrano. It flows into the Pacific Ocean at Doheny State Beach. San Juan Canyon provides a major part of the route for California State Route 74.
The Niles Cone is a groundwater basin in Alameda County, California, United States 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 east by the Diablo Range and on the west by San Francisco Bay. Surface runoff in the Alameda Creek catchment basin accounts for much of the recharge of the Niles Cone. The Alameda County Water District is responsible for management of the Niles Cone aquifer and has developed water treatment plants and pipelines for the conveyance of its waters to urban users. The Alameda County Water District also performs water quality monitoring of the Niles Cone Basin for total dissolved solids and other parameters.
Livermore Valley, formerly Valle De San Jose, is a valley in eastern Alameda County, in the East Bay region of the San Francisco Bay Area, northern California.
Amador Valley is a valley in eastern Alameda County, California and is the location of the cities of Dublin and Pleasanton. The valley is bounded by the foothills of the Diablo Range on the north and south, Pleasanton Ridge to the west, and Livermore Valley to the east.
Salmon Falls Creek is a tributary of the Snake River, flowing from northern Nevada into Idaho in the United States. Formed in high mountains at the northern edge of the Great Basin, Salmon Falls Creek flows northwards 121 miles (195 km), draining an arid and mountainous basin of 2,103 square miles (5,450 km2). The Salmon Falls Creek valley served as a trade route between the Native American groups of the Snake River Plain and Great Basin. Today, most of its water is used for irrigation.
La Vereda del Monte was a backcountry route through remote regions of the Diablo Range, one of the California Coast Ranges. La Vereda del Monte was the upper part of La Vereda Caballo,, used by mesteñeros from the early 1840s to drive Alta California horses to Sonora for sale.
Borrego Valley Groundwater Basin, located in the very southern region of California, is one of the driest basins in the state. With climate change predicted to have strong effects into foreseeable future, the region is viewed with a skepticism in the sustainable use of water at current rates of consumption. Both natural and man-made geographic divisions within this basin allow for a closer inspection of the various management techniques implemented throughout the years, and provide a basis for what may be pursued for an uncertain future.
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