Geology topics
Research about Texas
Source-linked reports with geographic coverage including Texas.
Withdrawals from the Edwards-Trinity aquifer system and contiguous hydraulically connected units, west-central Texas, December 1974 through March 1977
The Edwards-Trinity aquifer system and contiguous hydraulically connected units (fig. 1) are being studied as a part of the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) program. The aquifer system, which underlies about 40,000 mi 2 in west-central Texas, comprises mostly near-surface carbonate rocks, sand, and sandstone of Early Cretaceous age (Bush, 1986). Most groundwater withdrawals in this report are from the Edwards-Trinity aquifer system. However, two other sources contiguous and hydraulically connected to the Edwards-Trinity aquifer system yield appreciable water in the northwestern part of the study area. Withdrawals in Crane, Culberson, Loving, Ward, and Winkler Counties are from the Cenozoic alluvium. In Reeves County, approximately one-half of the withdrawals are from the Cenozoic alluvium and one-half are from the Edwards-Trinity system. Withdrawals in Andrews, Martin, northern Ector, and northern Midland Counties are from the High Plains aquifer. Other contiguous hydraulically connected minor aquifers are the source of withdrawals in counties along the northern boundary of the study area. No known potable water exists in the contiguous hydraulically connected units along the southeastern boundary of the system. This report documents the categories, rates, and distribution of withdrawals from the Edwards-Trinity aquifer system and contiguous hydraulically connected units during December 1974 through March 1977. The report includes withdrawal information from all or parts of the 50 counties in the study area. In those regions where only part of a county is within the study area, the percentage of the total county area was used to calculate the estimates of livestock and domestic withdrawals. The authors wish to thank the Texas Water Development Board for providing withdrawal information for this report.
Poisoning of Canada geese in Texas by parathion sprayed for control of Russian wheat aphid
Approximately 200 Canada geese ( Branta canadensis ) died at a playa lake in the Texas Panhandle shortly after a winter wheat field in the basin adjacent to the lake was treated with parathion to control newly invading Russian wheat aphids ( Diuraphis noxia ). No evidence of infectious disease was diagnosed during necropsies of geese. Brain ChE activities were depressed up to 77% below normal. Parathion residues in GI tract contents of geese ranged from 4 to 34 ppm. Based on this evidence, parathion was responsible for the goose mortalities. Parathion applications to winter wheat will undoubtedly increase if parathion is applied for control of both Russian wheat aphids and greenbugs ( Schizaphis graminum ). Geese may potentially be exposed to widespread applications of parathion from fall to spring, essentially their entire wintering period.
Dolomite dissolution rates and possible Holocene dedolomitization of water-bearing units in the Edwards aquifer, south-central Texas
Rates of dolomite dissolution can be used to test the concept, based on geomorphologic evidence, that a major part of the Edwards aquifer could have formed within the Holocene, a timeframe of approximately 10,000 years. During formation of the aquifer in the Edwards limestone (Cretaceous, Albian) of the Balcones fault zone, dolomite dissolution and porosity development were synchronous and the result of mixing-zone dedolomitization. Initiation of the mixing zone in the early Holocene (∼11,000 years before present) is suggested by the maximum age of formation of major discharge sites that allowed the influx of meteoric water into brine-filled, dolomitic preaquifer units. Dedolomitization, the dissolution of dolomite and net precipitation of calcite, has left aquifer units that are calcitic, and 40 vol.% interconnected pore space. The mass of dolomite missing is obtained by comparison of stratigraphically equivalent altered and unaltered units. One dissolution rate (1.76 × 10 −4 mmol dolomite kg H2O −1 yr −1 ) is determined from this mass, 10 4 yr reaction time, and a log-linear function describing the increase in mass discharge (three orders of magnitude) during aquifer formation. The second estimated dissolution rate is obtained from the mass transfer of dolomite to solution calculated from the increase in magnesium in pore fluids selected from the modern aquifer to represent a typical flowpath during aquifer formation. A reaction time of 10 4 yr for this mass transfer yields a rate of 0.56 × 10 −4 mmol dolomite kg H2O −1 yr −1 Both of these rates are comparable to modern rates of dolomite dissolution (0.3 to 4.5 × 10 −4 mmol dolomite kg H2O −1 yr −1 ) calculated from measured reaction times in the Tertiary Floridan aquifer system in Florida and the Madison aquifer in the Mississippian Madison Limestone of the Northern Great Plains. Similarity of these rates to the estimated paleo-rates of dolomite dissolution supports a 10 4 yr reaction timeframe. Both of these rates are comparable to modern rates of dolomite dissolution (0.3 to 4.5 × 10 −4 mmol dolomite kg H2O −1 yr −1 ) calculated from measured reaction times in the Tertiary Floridan aquifer system in Florida and the Madison aquifer in the Mississippian Madison Limestone of the Northern Great Plains. Similarity of these rates to the estimated paleo-rates of dolomite dissolution supports a 10 4 yr reaction timeframe. The Holocene reaction time also can be compared to a series of reaction times calculated by assuming that the mass of dolomite missing from the Edwards was removed at rates observed in the Floridan and Madison aquifers. These reaction times (for complete removal of dolomite) range from 2700 to 58,500 yr and span the Pleistocene-Holocene boundary. Finally, an estimated dolomite reaction rate during dedolomitization of the Edwards aquifer based on surface area of exposed dolomite [mmol cm −2 s −1 (millimoles per square centimeter per second)] may be approximated from reaction times. This rate is directly a function of the mass of dolomite removed and the surface area exposed per pore volume passing through the rock. The surface area is available from the observed dolomite rhomb size in unaltered rock. The rate of pore fluid movement is obtained from the averaged annual discharge. Rates during formation of the Edwards aquifer calculated from all reaction times range from 10 −13 to 10 −14 mmol dolomite cm −2 s −1 . These rates are faster than rates (10 −18 mmol cm −2 s −1 ), measured in the pure laboratory system, CaMg(CO 3 ) 2 CO 2 H 2 O, but slower than rates determined in an alpine stream study (10 −10 to 10 −11 mmol cm −2 s −1 ) where cold glacial melt water flows over dolostone. Dolomite dissolution rates from both the Edwards and other aquifers support the concept that a major part of the Edwards aquifer could have formed within the Holocene.
Land-surface subsidence resulting from ground-water withdrawals in the Houston-Galveston region, Texas, through 1987
The ground-water system in the Houston-Galveston region, Texas is composed of layers of sand and compressible clay. The system has been divided into two major aquifers, the Chicot and Evangeline, and the underlying Burkeville confining unit. The Chicot aquifer overlies the Evangeline aquifer. The Chicot aquifer contains the most permeable sand layers and also the more compressible clay layers.
Time-of-travel of solutes in the Trinity River from Dallas to Trinidad, Texas, May and August 1987
The U.S. Geological Survey (USGS), in cooperation with the city of Dallas, conducted a study of the time of travel of solutes during moderate flow conditions in a reach of the Trinity River from the outfall of the Dallas Central Wastewater Treatment Plant (DCWTP) to the USGS streamflow-gaging station 08062700, Trinity River at Trinidad, in May and August 1987. Previous USGS time-of-travel studies of this reach of the river (Ollman, 1973; 1975) provided low- and moderate-flow data. The data were included in the calibrartion of a mathematical water-quality model used by the city of Dallas and other public and private entities involved in water resources managemnt of the area. The purpose of this study was to provide additional data to extend calibration of that model to include moderately higher streamflow conditions.
Guidelines for collection and field analysis of water-quality samples from streams in Texas
This manual provides standardized guidelines and quality-control procedures for the collection and preservation of water-quality samples and defines procedures for making field analyses of unstable constituents or properties. Descriptions and procedures are given for several methods of sampling for which a variety of samplers may be used. Sample-processing devices such as sample churns and filtration apparatus are discussed along with methods of cleaning. Analyses for unstable constituents or properties are by necessity performed in the field. This manual addresses analytical techniques and quality assurance for: (1) Water temperature; (2) specific conductance; (3) pH; (4) alkalinity; (5) dissolved oxygen; and (6) bacteria.
Approximate water-level changes in wells completed in the Chicot and Evangeline aquifers, 1977-90 and 1989-90, and measured compaction, 1973-December 1989, in the Houston-Galveston region, Texas
This report is one in a series of reports that depict water-level changes since 1977 and compaction of subsurface material since 1973. The report was prepared in cooperation with the City of Houston and the Harris-Galveston Coastal Subsidence District, and presents approximate water-level changes in wells in the Chicot and Evangeline aquifers, 1977-90 and 1989-90 (figs. 1-4), and measured compaction, 1973-December 1989 (figs. 5 and 6), in the Houston-Galveston region.
Summary of data from the 1981-83 pilot study and 1985-89 operations of the Hueco Bolson Recharge Project, Northeast El Paso, Texas
Pumping and injection tests were conducted during a 1981-83 pilot study of the Hueco bolson recharge project in northeast El Paso. Water-level decline and buildup were measured in a recharge well and an observation well. The specific capacity of the recharge well during the October 1982 injection test was 18.3 gallons per minute per foot after 22.5 hours. The recharge well was redeveloped in June 1983. The specific capacity during the final pumping test of the pilot study was 27.5 gallons per minute per foot after 24.5 hours, compared to 35.8 gallons per minute per foot after 24 hours during"the May 1981 pre-injection pumping test. During the initial 5 years (1985-89) of operation of the Hueco bolson recharge project, water levels in the observation well were measured, and concentrations of selected water-quality constituents were determined. Water levels in six production wells located 0.25 to 0.6 mile from the injection wells of the recharge project declined at a rate of about 2 feet per year prior to 1985. Since 1980, water-level measurements indicate that the effects of pumping and recharge are approaching equilibrium.
Freshwater withdrawals in Texas, 1985
Since 1950, the U.S. Geological Survey (USGS) has estimated water use in the United States at 5-year intervals. Resulting reports tabulate water use by State and by water-resources region (major river basins) for a number of categories, such as irrigation, water supply, and industrial. In 1977, the USGS began the National Water-Use Information Program, designed to be a National source of accurate, consistent water-use data. The water-use project in Texas is part of the National Water-Use Information Program. The Texas District of the USGS compiles water-use information by county and by hydrologic unit using data collected by States agencies. A hydrologic unit is a geographic area representing part or all of a surface drainage basin, a combination of drainage basins, or a distinct hydrologic feature.
Potentiometric surface of the Edwards-Trinity aquifer system and contiguous hydraulically connected units, west-central Texas, winter, 1974-75
The potentiometric surface of the Edwards-Trinity aquifer system and contiguous hydraulically connected units (from December 1974 through February 1975) was mapped as part of the Edwards-Trinity Regional Aquifer-System Analysis (RASA) project. A major goal of the Edwards-Trinity RASA project is to understand and describe the regional flow system (Bush, 1986). The development of a digital ground-water flow model of the aquifer system is a key part of the project. This potentiometric map will be used in the calibration of the ground-water flow model and in understanding ground-water movement in the aquifer system. The map depicts the potentiometric surface of the major aquifers of the Edwards-Trinity aquifer system and contiguous units that form a continuous hydraulically connected regional aquifer within the study area in west-central Texas (fig. 1). The potentiometric surface of an aquifer is an imaginary surface defined by contouring locations of equal static head (the altitude to which water will rise in a well). The potentiometric surface map shows the direction of ground-water flow from higher to lower altitude. The study area extends beyond the aquifers of the Edwards-Trinity system to hydrologic divides, including the Colorado River and the Rio Grande (fig. 2). The data used to compile this map were obtained from the Texas Natural Resources Information System on magnetic tape and from Rees and Buckner (1980). The winter of 1974-75 (December 1974 through February 1975) was selected for mapping for two reasons: (1) More water-level data were available throughout the study area for this winter season than for other winter seasons, and (2) during winter there is almost no loss of ground water as a result of evaporation, irrigation withdrawals, and transpiration.