Geology topics

L. R. Woolfenden

Publications and source records attributed to L. R. Woolfenden.

6 recordsLinked to original sources

USGS1989

Geohydrology of the Escondido hydrologic subarea, San Diego County, California

The San Diego region of California is undergoing rapid growth with a corresponding increase in the demand for water. To update the basin plan developed in 1975 by the California Regional Water Quality Control Board, San Diego Region, water-level and water quality data for the 44-sq mi Escondido hydrologic subarea were collected and analyzed. Water-level measurements indicate that groundwater in most of the subarea was within 20 ft of land surface. Groundwater generally moves from the weathered crystalline rocks on hillsides into the alluvium. Groundwater moves from north to south in Reidy Canyon and from east to west in the alluvium along Escondido Creek. Water from all 20 wells sampled in 1987 had dissolved-solids concentrations greater than the U.S. Environmental Protection Agency recommended limit of 500 mg/L; concentrations ranged from 720 to 4,500 mg/L. Nitrate (as nitrogen) concentrations ranged from 1.1 to 86 mg/L. Water from 14 of the 20 wells had nitrate (as nitrogen) concentrations greater than the U.S. Environmental Agency recommended limit of 10 mg/L. (USGS)

Water-Resources Investigations Report↗

USGS1988

Aquifer-test evaluation and potential effects of increased ground-water pumpage at the Stovepipe Wells Hotel area, Death Valley National Monument, California

Ground-water use in the Stovepipe Wells Hotel area in Death Valley National Monument is expected to increase significantly if the nonpotable, as well as potable, water supply is treated by reverse osmosis. During the peak tourist season, October through March, ground-water pumpage could increase by 37,500 gallons per day, or 76%. The effects of this additional pumpage on water levels in the area, particularly near a strand of phreatophytes about 10,000 feet east of the well field, are of concern. In order to evaluate the effects of increased pumpage on water levels in the Stovepipe Wells Hotel area well field, two aquifer tests were performed at the well field to determine the transmissivity and storage coefficients of the aquifer. Analysis of the aquifer test determined that a transmissivity of 1,360 feet squared per day was representative of the aquifer. The estimated value of transmissivity and the storage-coefficient values that are representative of confined (1.2 x .0004) and unconfined (0.25) conditions were used in the Theis equation to calculate the additional drawdown that might occur after 1, 10, and 50 years of increased pumpage. The drawdown calculated by using the lower storage-coefficient value represents the maximum additional drawdown that might be expected from the assumed increase in pumpage; the drawdown calculated by using the higher storage-coefficient value represents the minimum additional drawdown. Calculated additional drawdowns after 50 years of pumping range from 7.8 feet near the pumped well to 2.4 feet at the phreatophyte stand assuming confined conditions, and from 5.7 feet near the pumped well to 0.3 foot at the phreatophyte stand assuming unconfined conditions. Actual drawdowns probably will be somewhere between these values. Drawdowns measured in observation wells during 1973-85, in response to an average pumpage of 34,200 gallons per day at the Stovepipe Wells Hotel well field, are similar to the drawdowns calculated by the Theis equation for the assumed increase in pumpage. (Author 's abstract)

Water-Resources Investigations Report↗

USGS1988

Ground-water conditions in the Anza-Terwilliger area, with emphasis on the Cahuilla Indian Reservation, Riverside County, California, 1973-86

Demand for groundwater in the 96-sq mi Anza Terwilliger area of California has increased in recent years because of population growth and agricultural development. In order to evaluate the potential effects of continued growth and development on the water resources of Cahuilla Indian Reservation, water level, land use, and water quality data were collected and analyzed. Water level measurements indicate that, as in previous years, groundwater normally moves toward streams in Anza and Terwilliger Valleys. However, during the summer, when pumping is at a maximum, groundwater moves toward two areas of groundwater withdrawal in Anza Valley. One area where groundwater levels were lowered extends to the northern boundary of Cahuilla Indian Reservation. Groundwater use during 1986 is estimated at 10,000 acre-ft, 6,000 acre-ft more than in 1973. The water table, however, generally has risen since 1973 due to the wet climatic conditions that generally have prevailed since 1976. Dissolved-solids concentrations during 1984-86 ranged from 184 to 1,320 mg/L. Water from two wells on Cahuilla Indian Reservation had dissolved-solids concentrations higher than the U.S. Environmental Protection Agency recommended limit for drinking water of 500 mg/L. No wells sampled on the reservation contained water with nitrate concentrations above the U.S. Environmental Protection Agency recommended limit of 10 mg/L. The observation-well network was found to be generally adequate, but the addition of one water level and two water quality observation wells would enhance its effectiveness. (USGS)

Water-Resources Investigations Report↗

USGS1986

Southern California alluvial basins regional aquifer-systems analysis: A bibliography

A bibliography for the Southern California Alluvial Basins Regional Aquifer-Systems Analysis includes references for about 3,500 publications related to the geohydrology of the 75,000 sq-mi region, which encompasses all of southern California except the Central Valley, the Channel Islands and the Pacific Ocean floor off southern California, and parts of adjacent states and Mexico. The report indexes the publications in six geographic categories and induces a list of sources of publications. Because of the large number of references in the bibliography, a system was developed for computer storage and retrieval. References can be retrieved by geographic location, author, or geohydrologic discipline and subject. The computer system allows for updating and addition of references.

California↗

USGS1984

Maps showing ground-water levels, springs, and depth to ground water, Basin and Range Province, Southern California

This report on ground-water levels, springs and depth to ground water in the Basin and Range province of southern California (see index map) was prepared as part of a program of the U.S. Geological Survey to identify prospective regions for further study relative to isolation of high-level nuclear waste (Bedinger, Sargent, and Reed, 1984), utilizing program guidelines defined in Sargent and Bedinger (1984). Also included in this report are selected references on pertinent geologic and hydrologic studies of the region. Other map reports in this series contain detailed data on ground-water quality, surface distribution of selected rock types, tectonic conditions, areal geophysics, Pleistocene lakes and marshes, and mineral and energy resources.

California↗

USGS1984

A ground-water-quality monitoring network for the Lower Mojave River Valley, California

A ground-water-quality monitoring network was developed for the Lower Mojave River valley to define the ground-water quality of the valley. Basin geohydrology, geology, land use and water-level and water-quality data were factors considered in developing objectives for an ideal network. These objectives were used in selecting well locations for the conceptual ground-water-quality monitoring network. The conceptual network was used as a guide in the design of the ground-water-quality monitoring network. Active monitoring sites are wells that are currently being monitored by some agency and were selected whenever possible because of budgetary constraints. In areas where no wells are currently being monitored, new well locations were selected and are considered proposed monitoring sites. A sampling regimen is also included. (USGS)

Water-Resources Investigations Report↗