Santa Clara valley aquifer

The Santa Clara valley aquifer is a groundwater aquifer located in the southern San Francisco Bay Area. The geology of the Santa Clara valley aquifer consists of a complex stratigraphy of permeable and impermeable units.[1] Management of aquifer resources is associated with the Santa Clara Valley Water District.

History

The first half of the 20th century saw groundwater extraction increase with the increasing regional population of the Bay Area. Between 1912 and 1966 artesian pressure levels dropped by as much as 200 ft (61 m). The decreasing pressure heads resulted in land subsidence of up to 15 ft (4.6 m). Recent work has shown that refined management practices have halted land subsidence.[2]

Hydrogeology

Well core data indicate that the Santa Clara valley aquifer consists of between four and six different water bearing units. The aquifer is composed of both confined and unconfined units. Water bearing units are generally coarse-grained and separated by relatively fine-grained units. The thicknesses of coarse-grained sections vary between 10 and 25 ft (3.0 and 7.6 m) in the southeast and between 50 and 200 ft (15 and 61 m) in the south-central and southwestern areas of the valley. Temperature data from monitoring wells indicate that horizontal groundwater flow occurs primarily above 775 ft (236 m) in southern-central regions and above 510 ft (160 m) in southeastern areas.[3]

Management

Stream stewardship, wholesale water supply and flood protection for Santa Clara County, California is provided by the Santa Clara Valley Water District.

References

1. Iwamura, T. I. (1995). "Hydrogeology of the Santa Clara and Coyote valleys ground water basins, California". In E. S. Sangines; D. A. Anderson; A. V. Busing (eds.). Recent Geologic Studies in the San Francisco Bay Area. Santa Barbara, CA: Pac. Sect., Soc. of Econ. Paleontol. and Mineral. pp. 173–192.
2. Schmidt, D., R. Bürgmann (2003). "Time-dependent land uplift and subsidence in the Santa Clara valley, California, from a large interferometric synthetic aperture radar data set". Journal of Geophysical Research. 108: 2416–2428. Bibcode:2003JGRB..108.2416S. doi:10.1029/2002JB002267.CS1 maint: multiple names: authors list (link)
3. M.W. Newhouse; R.T. Hanson; C.M. Wentworth; Rhett R. Everett; C.F. Williams; J.C. Tinsley; T.E. Noce & B.A. Carkin (2004). "Geologic, Water-Chemistry, and Hydrologic Data from Multiple-Well Monitoring Sites and Selected Water-Supply Wells in the Santa Clara Valley, California, 1999–2003". USGS Scientific Investigation Report 2004-5250.