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R. L. Ireland

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

9 recordsLinked to original sources
USGS1984

Land subsidence in the Santa Clara Valley, California as of 1980

From 1916 to 1966 in the San Jose area of Santa Clara Valley, California, deficient rainfall and runoff was accompanied by a fourfold increase in groundwater withdrawals. In response the artesian head declined 180-240 ft. The land surface subsided 12.7 ft in San Jose, due to compaction of the fine-grained compressible beds. The subsidence resulted in flooding of lands, and the compaction of the sediments caused compressional failure of many well casings. From 1967 to 1975, the artesian head recovered 70 to 100 feet due to a fivefold increase in surface water imports, favorable local water supply, decreased withdrawal, and increased recharge. In 1960, the Geological Survey installed extensometers in core holes 1,000 ft deep in San Jose and Sunnyvale. Measurements of compaction of the confined aquifer system obtained from these extensometers demonstrate the marked decrease in rate of compaction in response to the major head recovery since 1967. In San Jose the rate decreased from about 1 ft/yr in 1961 to 0.1 ft/yr in 1973. The subsidence has been stopped by raising the artesian head in the aquifers until it equaled or exceeded the maximum pore pressures in the fine-grained beds. However, the subsidence will recommence if the artesian head is drawn down appreciably below the levels of 1971-73. (USGS)

California↗
USGS1984

Evaluation of the potential for artificial ground-water recharge in eastern San Joaquin County, California — Phase 2

In response to the increasing demand on water supplies and declining water levels in eastern San Joaquin County, the U.S. Geological Survey, in cooperation with the San Joaquin County Flood Control and Water Conservation District, is evaluating the potential for artificially recharging the aquifer system in eastern San Joaquin County, Calif. Phase 1 of this study evaluated the geologic and hydrological conditions in the area and selected 20 drill sites in three areas of high potential for artificial recharge of the aquifer system. In phase 2, test holes were drilled. This report is on phase 2, and summarizes the data collected during the drilling and evaluates the suitability of the drilled areas for their potential for artificial recharge. Two areas seem to have a fair potential for artificial recharge of the aquifer system using the basin-spreading method: (1) The flood plain area along the Mokelumne River north of Lockeford, and (2) an area northeast of Linden along the Calaveras River. (USGS)

California↗
USGS1982

Land subsidence in the San Joaquin Valley, California, as of 1980

Land subsidence due to ground-water overdraft in the San Joaquin Valley began in the mid-1920 's and continued at alarming rates until surface was imported through major canals and aqueducts in the 1950 's and late 1960's. In areas where surface water replaced withdrawal of ground-water, water levels in the confined system rose sharply and subsidence slowed. In the late 1960 's and early 1970 's water levels in wells recovered to levels of the 1940 's and 1950 's throughout most of the western and southern parts of the Valley, in response to the importation of surface water through the California aqueduct. During the 1976-77 drought data collected at water-level and extensometer sites showed the effect of heavy demand on the ground-water resevoir. With the ' water of compaction ' gone, artesian head declined 10 to 20 times as fast as during the first cycle of long-term drawdown that ended in the late 1960's. In the 1978-79 water levels recovered to or above the 1976 pre-drought levels. The report suggests continued monitoring of land subsidence in the San Joaquin Valley. (USGS)

Open-File Report↗
USGS1973

Preliminary investigation of land subsidence in the Sacramento Valley, California

Although a number of agencies have made leveling surveys in Sacramento Valley and a valleywide network of first- and second-order control exists, few areas have sufficient control for determining whether land subsidence has occurred and if so, how much, within the time span of vertical control. Available data suggest that 0.2 to 0.9 foot (0.06 to 0.3 m) of subsidence probably has occurred from 1935-42 to 1964 in an extensive agricultural area of heavy ground-water pumping between Zamora and Davis, and that as much as 2 feet (0.6 m) of subsidence has occurred in at least two areas of pumping overdraft--east of Zamora, and west of Arbuckle. A comparison of maps showing long-term water-level decline and average annual ground-water pumpage indicates several other areas of probable subsidence. In six general areas--northwest of Sacramento; northeast of Sacramento; southeast of Yuba City; 10 miles (16 km) north of Willows; 20 miles (32 km) north of Willows; and especially in the Arbuckle area,ground-water declines have quite probably produced significant subsidence. In two areas of most intensive pumping, no long-term water-level declines have occurred, and no subsidence is indicated. If problems of land subsidence are of concern in Sacramento Valley, and if estimates of historic subsidence or subsidence potential are needed, serious consideration should be given to a field program of basic-data collection. Second-order leveling along a few carefully selected lines of existing control, and the installation and operation of two or three compaction recorders in areas of continuing water-level decline, would provide helpful data for estimating .past and future subsidence.

California↗