Arroyo de la Laguna is a
[U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data]
The National Map
, accessed March 15, 2011 southward-flowing
stream in
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 ...
, United States which originates at the confluences of
South San Ramon Creek and
Arroyo Mocho
Arroyo Mocho is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed March 15, 2011 stream which originates in the far northeastern corner of Santa Clara County and flows northwesterly into ...
. The Arroyo de la Laguna is fed by tributaries in the
Amador Valley
Amador Valley is a valley in eastern Alameda County, California and is the location of the cities of Dublin and Pleasanton. Part of Tri-Valley, the valley is bounded by the foothills of the Diablo Range on the north and south, Pleasanton Ridge t ...
and certain eastern slope drainages of the
Diablo Range
The Diablo Range is a mountain range in the California Coast Ranges subdivision of the Pacific Coast Ranges in northern California, United States. It stretches from the eastern San Francisco Bay area at its northern end to the Salinas Valley are ...
; these tributaries include
Arroyo Valle
Arroyo Valle or Arroyo Del Valle is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed March 15, 2011 westward-flowing stream that begins in northeastern Santa Clara County, California ...
and Sinbad Creek. Arroyo del la Laguna is the major tributary to
Alameda Creek which in turn flows into the
San Francisco Bay.
From prehistoric times much of the eastern part of the Amador Valley consisted of a lake known as
Tulare Lake
Tulare Lake () ( Spanish: ''Laguna de Tache'', Yokuts: ''Pah-áh-su'') is a freshwater dry lake with residual wetlands and marshes in the southern San Joaquin Valley, California, United States. After Lake Cahuilla disappeared in the 17th century ...
. With development of the valley starting in the 19th century, drainage alterations in this watershed reduced the lake to a watercourse now called the Arroyo de la Laguna.
Hydrogeology
In the northern portion of the Arroyo de la Laguna catchment basin, the
Tassajara Formation
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 ...
underlies
Quaternary valley fill material. Contacts of these two formations are often indistinguishable due to similarities of physical characteristics. The prism of sediments identified as valley fill materials contains from eight to ten separate zones of sand and gravel separated by zones of silt and clay.
Rapid development and other historic changes in the upper watershed have caused severe instability in the lower 5 miles of the Arroyo de la Laguna.
See also
*
List of watercourses in the San Francisco Bay Area
These watercourses (rivers, creeks, sloughs, etc.) in the San Francisco Bay Area are grouped according to the bodies of water they flow into. Tributaries are listed under the watercourses they feed, sorted by the elevation of the confluence so tha ...
*
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 ...
*
Pleasanton Fault The Pleasanton Fault is a seismically active geological structure in Alameda County, California, Alameda County and Contra Costa County, California, United States, USA. The existence of the fault is disputed as geotechnical reports have found no evi ...
*
Tassajara Formation
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 ...
References
{{DEFAULTSORT:Arroyo De La Laguna
Rivers of Alameda County, California
Tributaries of Alameda Creek