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John A. Singer

Publications and source records attributed to John A. Singer.

7 recordsLinked to original sources
USGS1979

Water resources of the Santa Ynez Indian Reservation, Santa Barbara County, California

The Santa Ynez Indian Reservation is situated above a bedrock ridge that forms the southern boundary of the Santa Ynez upland ground-water basin. A pumping depression exists upgradient from the reservation, and water levels have declined an average of 1.0 to 1.5 feet per year since the 1940's. This decline in the water level has led to the cessation of perennial flow in Zanja de Cota Creek that traverses the reservation. In the past this creek was fed by the natural discharge of water from the ground-water basin. Water-bearing rock beneath the reservation is limited in thickness and may become unusable as a water supply source in the near future if water levels continue to decline. The chemical quality of water beneath the reservation is generally acceptable for both irrigation and domestic use; however, large-scale pumping could induce the flow of contaminated water from an area just upgradient. Declines in ground-water levels and the existence of fecal contamination upgradient from the reservation make the successful development of a groundwater supply for the reservation doubtful.

California↗
USGS1973

Geohydrology and artificial-recharge potential of the Irvine area, Orange County, California

The Irvine area is in hydraulic continuity with the rest of the coastal plain in Orange County. Factors that distinguish the aquifer section of the Irvine area from that in other parts of the coastal plain are a low permeability, a high clay and silt content, and a thin alluvial sequence. Rapid facies change and the large percentage of silt and clay in the section locally result in confining conditions. The aquifer, most of which is included in the Fernando Formation, is as much as 1,300 feet thick beneath parts of the plain. The alluvium overlying the Fernando Formation averages about 200-250 feet in thickness and also contains significant amounts of silt and clay. Transmissivities range from 25,000 to 100,000 gallons per day per foot in the Irvine area, values which are much lower than those in the rest of the coastal plain in Orange County. Water levels have recovered as much as 60 feet from the low levels of the early 1950's. Water-level maps indicate that in the winter non-pumping season water tends to move toward upper Newport Bay and the rest of the coastal plain. During the summer pumping season a cone of depression develops, reversing the winter gradient. The average dissolved-solids content of the ground water is about 800 milligrams per liter. The most prevalent cations are sodium and calcium; the most prevalent anions are bicarbonate and sulfate. No long-term degradation of water quality has occurred, with the exception of a slight increase in dissolved solids. No areas in the Irvine area are suitable for the large-scale spreading of water for artificial recharge. Clay and silt predominate in the section beneath the Tustin plain, and in the foothill areas either bedrock is close to the surface or the alluvium is fine grained.

Open-File Report↗
USGS1969

A study of deep aquifers underlying coastal Orange County, California

Deep untapped aquifers of late Pliocene age, which contain water having 1,000 to 2,000 milligrams per liter of dissolved solids, underlie most of the coastal part of Orange County. Inland from the Newport-Inglewood structural zone, the depth to the base of aquifers containing fresh water ranges from 1,000 to 2,500 feet below mean sea level. The aquifers are composed of fine to medium sand with locally occurring beds of coarse sand and gravel. Permeability generally ranges from less than 50 gallons per day per square foot to 300 gallons per day per square foot. Pressure head increases with depth of the aquifer to as much as 40 feet above land surface near the base of fresh water. The water is of the sodium bicarbonate type, increasing in salinity with depth. Organic material imparts an amber color to the water, which becomes more distinct with depth. A test well, drilled to 926 feet and perforated from 784 to 884 feet, yielded 1,950 gallons per minute with about 90 feet of drawdown. The water is of the sodium bicarbonate type with dissolved solids of 225 mg/1. Additional studies are needed to evaluate the possibilities of subsidence due to pumping from the deep aquifers, to determine the vertical and horizontal permeabilities of confining beds, and to monitor the changes in water quality and water level.

California↗