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Clark J. Londquist

Publications and source records attributed to Clark J. Londquist.

6 recordsLinked to original sources
USGS1997

Ground-water hydrology and water quality of Irwin Basin at Fort Irwin National Training Center, California

Geohydrologic data were collected from Irwin Basin at Fort Irwin National Training Center in the Mojave Desert of southern California by the U.S. Geological Survey during 199296 to deter mine the quantity and quality of ground water available in this basin. In addition to data collected from existing wells and test holes, 17 monitoring sites were constructed in Irwin Basin to provide data on subsurface geology, ground-water levels, and ground-water quality. Eleven of these sites were multiple-well monitoring sites that were constructed to provide depth-dependent geohydrologic data in the aquifer system. The aquifer system of Irwin Basin, defined on the basis of hydrologic data collected from wells in Irwin Basin, consists of an upper and a lower aquifer. A 1994 water-table contour map shows that a cone of depression beneath Irwin Basin well field has developed as a result of ground-water development. Water-quality samples collected from Irwin Basin wells to determine potential sources of ground-water degradation indicate that water in three areas in the basin contains high nitrate and dissolved-solids concentrations. The stable isotopes of oxygen and hydrogen indicate that present-day precipitation is not a major source of recharge in this basin. Tritium and carbon-14 data indicate that most of the basin was recharged before 1953 and that this water may be more than 14,000 years old.

Calfornia↗
USGS1990

Ground-water resources of Honey Lake Valley, Lassen County, California, and Washoe County, Nevada

Honey Lake Valley is a 2,200 sq-mi, topographically closed basin about 35 miles northwest of Reno, Nevada. Unconsolidated basin-fill deposits on the valley floor and fractured volcanic rocks in northern and eastern uplands are the principal aquifers. In the study area, about 130,000 acre- ft of water recharges the aquifer system annually, about 40% by direct infiltration of precipitation and about 60% by infiltration of streamflow and irrigation water. Balancing this is an equal amount of groundwater discharge, of which about 65% evaporates from the water table or is transpired by phreatophytes, about 30 % is withdrawn from wells, and about 5% leaves the basin as subsurface outflow to the east. Results of a groundwater flow model of the eastern part of the basin, where withdrawals for public supply have been proposed, indicate that if 15,000 acre-ft of water were withdrawn annually, a new equilibrium would eventually be established by a reduction of about 60% in both evapotranspiration and subsurface outflow to the east. Hydrologic effects would be minimal at the western boundary of the flow-model area. Within the modeled area, the increased withdrawals cause an increase in the simulated net flow of groundwater eastward across the California-Nevada State line from about 670 acre-ft/yr to about 2,300 acre-ft/yr. (USGS)

California, Nevada↗
USGS1981

Digital model of the unconsolidated aquifer system in the Modesto area, Stanislaus and San Joaquin Counties, California

A digital mathematical model of the unconsolidated alluvial aquifer system in the Modesto area, Calif., has been developed which can be used to determine the effects of increased pumping and water use of future water levels in the aquifer system. The model is divided into two units. The lower unit is confined in the western part of the study area by a confining clay bed; elsewhere in this unit the aquifer is unconfined. The upper unit represents an unconfined aquifer and lies above the clay bed or its extension. Where the clay bed is absent the upper and lower units are considered as a single aquifer. The model, as calibrated, can evaluate with reasonable accuracy the effects on water levels of changing stresses and stress patterns only within the area of primary interest for the upper unit. In other areas of the upper unit and for the lower unit, predicted changes should be looked upon as, at best, representing only general trends. (USGS)

California↗
USGS1976

Potential for development of ground water at a test site near Truro, Massachusetts

An aquifer test was carried out at a possible ground-water development site in Truro, Massachusetts. Average lateral hydraulic conductivity for material in the screened interval of the test well is 216 feet per day. Specific yield of the material at water-table depth is about 0.10. Anisotropy, or ratio of lateral hydraulic conductivity to vertical hydraulic conductivity, is between 1 and 5 for the uppermost 60 feet of saturated material, but is probably much higher at greater depths. Calculation of drawdown after pumping 200 days at 1 million gallons per day indicates lateral intrusion of saline water from the sea would not reach the well and that the area of ground-water contribution would be sufficient to intercept an amount of average annual recharge equal to pumpage. Using the previously determined aquifer constants and the maximum drawdown after 200 days of pumping at 1 million gallons per day, it was determined that a stable upconing adjustment of the fresh water/saline-water interface would occur below the pumping well, and saline water would not reach the well through vertical intrusion. (Woodard-USGS)

Open-File Report↗
USGS1973

Contour map of the bedrock surface, Ludlow Quadrangle, Massachusetts

Contours show the altitude of the bedrock surface. The position of the contours is based largely on data from wells and test holes supplemented by knowledge of the geologic history of the region. The map show the configuration of the bedrock surface if all unconsolidated earth materials were removed.

Massachusetts↗