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Research about Texas

Source-linked reports with geographic coverage including Texas.

At least 937 records · Page 52Linked to original sources
USGS1990

Ground-water withdrawals, water-level changes, land-surface subsidence, and ground-water quality in Fort Bend County, Texas, 1969-87

Fort Bend County, which has one of the fastest growing populations of all counties in the United States, is dependent entirely on ground water for public supply. Since 1969, at least 90 large-capacity wells have been drilled, of which 57 were public supply wells, 23 were irrigation wells, and 10 were industrial wells. All but seven of the new public-supply wells are located in the northeastern part of the county. The withdrawal of ground water in Fort Bend County increased from 56 million gallons per day in 1969 to 72 million gallons per day in 1982, and then decreased to 53 million gallons per day in 1986. Withdrawals for public supply increased from 4 million gallons per day in 1969 to 28 million gallons per day in 1986. Withdrawals for irrigation averaged 38 million gallons per day during 1969-82 and in 1984, but averaged 20 million gallons per day in 1983, 1985, and 1986. Withdrawals for industrial use declined from 13 million gallons per day in 1969 to 5 million gallons per day in 1986. Water levels in wells screened in the upper unit of the Chicot aquifer generally fluctuated less than 4 feet between 1968-69 and 1987. During the same period, water-level declines in wells screened in the lower unit of the Chicot aquifer ranged from less than 10 feet in most of the western part of the county to 100 feet in the northeastern corner. In the southwestern part of the county, the decline was less than 20 feet. Hydrographs of wells completed in the lower unit of the Chicot showed that water levels continued to decline from 1969 to the early 1980's. The hydrographs of wells located outside of the northeast area generally show a stabilization of water levels corresponding to the reduction in withdrawals after 1982 in Fort Bend County and in the neighboring Houston metropolitan area to the northeast. Withdrawals from the Evangeline aquifer increased from 15 percent of the total in 1969 to 50 percent in 1986. Water-level declines in wells screened in the Evangeline aquifer during the same period ranged from less than 25 feet in the northwestern part of the county to 125 feet in the northeastern part. In the southwestern one-quarter of the county, the decline was less than 50 feet. Declines in the potentiometric surfaces of the aquifers have caused compaction of clay resulting in land-surface subsidence. Between 1906 and 1978, about 65 percent of the county subsided more than 0.5 foot. Studies in the Houston area have shown that most clay compaction occurs in the Chicot aquifer and that the compressibility of the clays increases towards the coast. The total thickness of clays in the Chicot aquifer increases from less than 150 feet in the northwestern part of Fort Bend County to more than 350 feet along the eastern border. The total thickness of clay in the Evangeline aquifer increases from an average of about 700 feet in the northwest to about 1,100 feet in the east. The northeastern part of Fort Bend County is most susceptible to future subsidence because it is the area where the largest water-level declines have occurred and where the thickest, most compressible clays in the county are found. The concentrations of dissolved solids in water from wells in Fort Bend County have not changed appreciably from 1969 to 1987. The median concentrations of dissolved solids are 475 milligrams in water from wells in Fort Bend per liter in water from the upper unit of the Chicot aquifer, 337 milligrams per liter in water from the lower unit of the Chicot aquifer, and 307 milligrams per liter in water from the Evangeline aquifer.

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USGS1990

Relation between urbanization and water quality of streams in the Austin area, Texas

Selected water-quality properties and constituents of stormflow and base flow were compared to determine the relation between the degree of urbanization and the water quality in a drainage basin. Samples were collected during three flow categories (rising stage and falling stage of stormflow and base flow) at 18 sites on 11 streams. The degree of urbanization is indicated by grouping the sample sites by development based on the percent of impervious cover in the drainage basin. Four development classifications rural, mostly rural, partly urban, and urban were identified based on ranges of impervious cover in the drainage basins. For each site and development classification, the concentrations and densities in samples collected during the rising stage and falling stage of stormflow and during base flow were compared. Samples were collected for physical organics and inorganics, nutrients, indicator bacteria, inorganic trace elements, synthetic organic compounds, and radiochemical constituents. Except for dissolved solids, the concentrations in samples collected during the rising stage of stormflow were larger than in samples collected during the falling stage. The concentrations in stormflow were larger than in base flow. The concentrations and densities of suspended solids, biochemical oxygen demand, total organic carbon, total nitrogen, total phosphorus, fecal coliforms, and fecal streptococci increased with increased impervious cover. For the five sample sites that had a sufficient number of samples from each flow category for statistical comparisons, the median concentrations in samples collected during the rising stage and falling stage of stormflow were significantly larger than the base-flow median concentrations. In addition, the concentrations in samples collected during the rising stage were more variable and significantly larger than in those collected during the falling stage of stormflow. Statistical differences between the median concentrations in samples collected during the rising stage and falling stage of stormflow were not evident for the site with the mostly rural drainage basin. Except for dissolved solids, the median concentrations in samples collected during the rising stage and falling stage of stormflow increased with increasing development classifications. For base flow, the median concentrations were also larger for more urban classifications than for the other classifications. The ratio of the number of samples with detectable concentrations to the total number of samples analyzed for 18 inorganic trace elements and the concentrations of many of these minor constituents increased with increasing development classifications. Twenty-two of the 42 synthetic organic compounds for which samples were analyzed were detected in one or more samples. The compounds were detected more frequently and in larger concentrations at the sites with more urban classifications.

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USGS1989

Distribution and migration of adult striped bass in Lake Whitney, Texas

Thirty adult (3.2–8.6 kg) striped bass Morone saxatilis were tagged with ultrasonic transmitters and tracked for up to 475 d in 9,510‐hectare Lake Whitney, a Texas reservoir, to determine seasonal distribution, migration patterns, and water temperatures occupied. Striped bass distribution in summer was limited to an area near the dam, where they survived temperatures as high as 29.0°C. Tagged fish generally were found in the coolest water available (27.0–29.0°C) that contained adequate dissolved oxygen (>4.0 mg/L) in summer and occupied the warmest water (7.4–8.8°C) in winter. For the rest of the year, the fish were distributed throughout available water temperatures. Beginning in autumn, most striped bass moved up the reservoir to and into the main tributaries and remained there until spring, when they returned to the main reservoir. No spawning run up main tributaries was observed in either of the two study years, possibly due to low inflows. Individual fish displayed a preference for certain areas to which they returned yearly.

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USGS1989

Suspected fusariomycotoxicosis in sandhill cranes (Grus canadensis): clinical and pathological findings.

In 1985 and 1986, large-scale natural die-offs of sandhill cranes in Texas were attributed to fusariomycotoxicosis. These birds demonstrated a progressive loss of motor control to the neck, wings, and legs. Based on necropsy and/or histopathology of 31 cranes, the most common lesions involved skeletal muscle and included hemorrhages, granulomatous myositis, thrombosis, and vascular degeneration. Serum chemistry results revealed that levels of creatinine kinase, aspartate aminotransferase, and alanine aminotransferase were above published normals. However, only alanine aminotransferase was higher in clinically affected cranes than in normal cranes collected from the same area.

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USGS1989

Summary of hydrologic data for the San Gabriel River basin and Edwards Aquifer, Georgetown area, Texas, water year 1988

The Edwards aquifer is the principle source of freshwater for municipal, domestic, and industrial users in the Georgetown area. Other sources of freshwater are the streams draining the San Gabriel River basin and Lake Georgetown. Lake Georgetown, located on the North Fork San Gabriel River west of Georgetown, is a freshwater supply for some municipalities in the area, water in the San Gabriel River basin also supplies a variety of needs east of Georgetown. Because of the importance of the Edwards aquifer and the surface waters in the area, the U.S. Geological Survey, in cooperation with the city of Georgetown, conducted a monitoring program of the Edwards Aquifer and principal streams during water year 1988. The study area centered on Georgetown and encompassed an area of about 150 square miles (fig. 1). The freshwater resources in the Georgetown area have been the subject of three recent reports. Baker and others (1986) described the Edwards aquifer and the relation between recharge and discharge. Krietier and others (1987) provided fracture analysis, geologic mapping, ground-water chemistry, and the relation between rainfall and recharge in the study area. Land and Dorsey (1988) conducted an investigation to reassess the inclusion of the Georgetown Limestone as one of the geologic units comprising the Edwards aquifer. In addition, the Geological Survey publishes streamflow and water-quality data in the Water Resources Data for Texas report on an annual basis. The primary purpose of this report is to present a summary of the hydrologic data collected from the streams draining the San Gabriel River basin and from the Edwards aquifer during the 1988 water year (October 1987–September 1988). A secondary purpose is to add perspective to the 1988 data by including data from the previous 2 years (1986 and 1987) when available. The scope of the report is limited to the Georgetown area (fig. 1) and to data collected by the Geological Survey.

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USGS1989

Approximate altitude of water levels in wells in the Chicot and Evangeline aquifers in the Houston area, Texas, spring 1989

This report shows the altitudes of water levels in the Chicot and Evangeline aquifers in the Houston metropolitan area, Texas. Of the 425 wells measured, 307 were used to construct the maps of potentiometric surface. The Chicot and Evangeline aquifers are composed of several sand layers, each with a separate potentiometric surface. These maps, however, show a single potentiometric surface which represents the collective water levels for the sand layers comprising each aquifer. Maps showing the altitudes of water levels have been published in many reports on ground-water development in the Houston area, the most recent of which (Gabrysch and others, 1988) presented maps of the altitudes of potentiometric surfaces for 1988.

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USGS1989

Physical and chemical data from two water-quality surveys of streams in the Lewisville Lake watershed, north-central Texas, 1984 and 1985

Physical and chemical water-quality data and nitrogen and phosphorus yields for 29 sites sampled in two synoptic surveys of streams within the Lewisville Lake watershed are presented in this report. The two synoptic surveys were conducted in March 1984 and March 1985, as a reconnaissance and assessment of water quality and nitrogen and phosphorus yields throughout the watershed. This work was cooperatively funded by the city of Dallas and the U.S. Geological Survey (USGS) as part of a hydrologic study to quantify nonpoint nutrient loads to Lewisville Lake.

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USGS1989

Approximate water-level changes in wells completed in the Chicot and Evangeline aquifers, 1977-89 and 1988-89, and measured compaction, 1973-89, in the Houston-Galveston region, Texas

This report presents data on water-level changes in the Chinot and Evangeline aquifers during 1977-89 and 1988-89 and data on measured compaction during 1973-89. Measurements of water level in 307 wells were used to construct the maps showing water-level changes. Compaction data were obtained from 12 wells equipped with compaction monitors at 11 sites.

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USGS1989

Water-resources activities of the U.S. Geological Survey in Texas— Fiscal year 1988

This report describes the activities of the U.S. Geological Survey Water Resources Division in Texas for fiscal year 1988. The project number, cooperating agencies, project chief, period of project, location, problem, objective, approach, progress, reports in preparation, and reports published are given for each project in the Texas District. The report also includes a list of reports published or approved for publication during fiscal year 1988, and a plate showing the locations of the Subdistrict areas and active surface-water stations in Texas.

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USGS1989

Flow pattern in regional aquifers and flow relations between the lower Colorado River valley and regional aquifers in six counties of southeastern Texas

The lower Colorado River discussed in this report consists of the 318- river-mile reach from Mansfield Dam near Austin, Texas, to the Gulf of Mexico. The river is underlain directly or indirectly by six regional aquifers the Trinity Group, Edwards, Carrizo-Wilcox, Queen City, Sparta, and Gulf Coast; the Trinity Group aquifer is further subdivided into the lower Trinity, middle Trinity, and upper Trinity aquifers. Generalized potentiometric-surface maps of each regional aquifer show the ground-water-flow pattern near the river valley. Each regional aquifer discharges water to the lower Colorado River valley, particularly in the outcrop area of each aquifer. Only the Gulf Coast aquifer in central Wharton County appears to be recharged by water in the river valley. A summary map shows those subreaches of the lower Colorado River that gain water from the aquifers and those subreaches that lose water to the aquifers.

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USGS1988

Field validation of a habitat suitability index model for the American oyster

A habitat suitability index (HSI) model, developed for the American oyster, Crassostrea virginica , along the Gulf of Mexico, was field tested on 38 0.1-ha reef and nonreef sites in Galveston Bay, Texas. The HSI depends upon six (HSI1) or, optionally, eight (HSI2) variables. The six variables are percent of bottom covered with suitable cultch (V 1 ), mean summer water salinity (V 2 ), mean abundance of living oysters (V 3 ) (a gregarious settling factor), historic mean water salinity (V 4 ), frequency of killing floods (V 5 ), and substrate firmness (V 6 ). The optional variables are the abundance of the southern oyster drill Thais haemostoma (V 7 ), and the intensity of the oyster pathogen Perkinsus marinus (V 8 ). The HSI values were lowest at high and low salinity sites and highest at intermediate-salinity sites. To validate the model, the hypothesis that the output of the HSI model was correlated with oyster density was therefore tested. A significant correlation was found between HSI1 and oyster density (Kendall Tau Beta correlation coefficient, τ=0.674, p<0.001, n=38); however, a statistical independence problem exists with the above test, that is, oyster density is both the independent standard for the test and a variable in the model. A regression model was constructed to test the relationship between log-transformed oyster density values (dependent variable) and the other variables of the model (independent variables). Most variation (r 2 =0.72, r=0.85) in the log-transformed density values were explained by a regression model that contained V 2 , V 4 , V 5 , V 6 , V 7 , and V 8 as independent variables. The regression model was useful in constructing a modified HSI model (MHSI). A significant correlation (τ=0.674, p<0.05, n=10) was found between MHSI1 values and oyster densities from reefs closed to harvesting. The MHSI improves upon the original model by (i) simplifying the model structure, (ii) removing the requirement to measure V 3 , (iii) accounting better for the negative effects of high salinity, disease, and parasitism upon oysters, and (iv) eliminating the statistical independence problem by dropping V 3 from the model. The MHSI should be tested against a new, independently-collected data set.

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USGS1988

Seismicity map of the state of Texas

This map is one of a series of seismicity maps produced by the U.S. Geological Survey that show earthquake data of individual states or groups of states at the scale of 1:1,000,000. This map shows only those earthquakes with epicenters located within the boundaries of Texas, even though earthquakes in nearby states may have been felt or may have caused damage in Texas. The data in table 1 were used to compile the seismicity map; these data are a corrected, expanded, and updated (through 1987) version of the data used by Algermissen (1969) for a study of seismic risk in the United States. The locations and intensities of some earthquakes were revised and intensities were assigned where none had been before. Many earthquakes were added to the original list from new data sources as well as from some old data sources that has not been previously used. The data in table 1 represent best estimates of the location of the epicenter, magnitude, and intensity of each earthquake on the basis of historical and current information. Some of the aftershocks from large earthquakes are listed, but not all, especially for earthquakes that occurred before seismic instruments were universally used.

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USGS1988

Water-resources activities of the U.S. Geological Survey in Texas– Fiscal year 1987

The U.S. Geological Survey (USGS) was established by an act of Congress on March 3, 1879, to provide a permanent Federal agency to conduct the systematic and scientific classification of the public lands and to examine the geological structure, mineral resources, and products of national domain. An integral part of that original mission includes publishing and disseminating the earth science information needed to understand, to plan the use of, and to manage the Nation's energy, land, mineral, and water resources. Since 1879, the research and fact-finding role of the USGS has grown and been modified to meet the changing needs of the Nation it serves. As part of that evolution, the USGS has become the Federal Government's largest earthscience research agency, the Nation's largest civilian mapmaking agency, the primary source of data on the Nation's surface- and ground-water resources, and the employer of the largest number of professional earth scientists. Today's programs serve a diversity of needs and users. Programs include: Conducting detailed assessments of the energy and mineral potential of the Nation's land and offshore areas. Investigating and issuing warnings of earthquakes, volcanic eruptions, landslides, and other geologic and hydrologic hazards. Conducting research on the geologic structure of the Nation. Studying the geologic features, structure, processes, and history of the other planets of our solar system. Conducting topographic surveys of the Nation and preparing topographic and thematic maps and related cartographic products. Developing and producing digital cartographic data bases and products. Collecting data on a routine basis to determine the quantity, quality, and use of surface and ground water. Conducting water-resources appraisals in order to describe the consequences of alternative plans for developing land and water resources. Conducting research in hydraulics and hydrology and coordinating all Federal water-data acquisition. Using remotely sensed data to develop new cartographic, geologic, and hydrologic research techniques for natural resources planning and management. Providing earth-science information through an extensive publications program and a network of public access points. Along with its continuing commitment to meet the growing and changing earthscience information needs of the Nation, the USGS remains dedicated to its original mission to collect, analyze, interpret, publish, and disseminate information about the natural resources of the Nation providing "earth science in the public service."

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