A5013110379- Groundwater and Isotope Geochemistry
- Water Quality and Resources Studies
- Groundwater flow and contamination studies
- Chemical Analysis and Environmental Impact
- Archaeology and Natural History
- Water Treatment and Disinfection
- Hydrocarbon exploration and reservoir analysis
- Hydrology and Watershed Management Studies
- Geological and Tectonic Studies in Latin America
- Karst Systems and Hydrogeology
- Atmospheric and Environmental Gas Dynamics
- Aquatic Invertebrate Ecology and Behavior
- Geological and Geochemical Analysis
- Coal Properties and Utilization
- Water resources management and optimization
- Soil and Water Nutrient Dynamics
- Methane Hydrates and Related Phenomena
- Hydrology and Drought Analysis
- Ecology and biodiversity studies
- Flood Risk Assessment and Management
- Isotope Analysis in Ecology
United States Geological Survey
1991-2015
Hartford Financial Services (United States)
2008
Pacific Island Ecosystems Research Center
2006
Texas Tech University
2006
Perchlorate (ClO4-) occurrence in groundwater has previously been linked to industrial releases and the historic use of Chilean nitrate fertilizers. However, recently a number occurrences have identified for which there is no obvious anthropogenic source. Groundwater from an area 155 000 km2 56 counties northwest Texas eastern New Mexico impacted by presence ClO4-. Concentrations were generally low (<4 ppb), although some areas are concentrations up 200 ppb. ClO4- distribution not related...
As part of the National Water-Quality Assessment Program, U.S. Geological Survey collected and analyzed groundwater samples during 1996-2006 from San Antonio segment Edwards aquifer central Texas, a productive karst developed in Cretaceous-age carbonate rocks. These Program studies provide an extensive dataset geochemistry water quality, consisting 249 136 sites (wells springs), including (1) wells completed shallow, unconfined, urbanized vicinity (shallow/urban unconfined category), (2)...
Concentrations of halogenated volatile organic compounds (VOCs) were determined by gas chromatography (GC) with an electron-capture detector (GC-ECD) and mass spectrometry (GC-MS) in 109 groundwater samples from five study areas the United States. In each case, untreated water sample was used for drinking-water purposes or a monitoring well area near source. The minimum detection levels (MDLs) 25 VOCs that identified GC-ECD chromatograms, typically, two to more than four orders magnitude...
Karst aquifers occur in a range of climatic and geologic settings. Nonetheless, they are commonly characterized by their vulnerability to water-quality impairment. Two karst aquifers, the Edwards aquifer south-central Texas Upper Floridan western Florida, were investigated assess factors that control movement contaminants public-supply wells (PSWs). The geochemistry samples from selected PSW or wellfield each was compared with nearby monitoring regional PSWs. Geochemistry results integrated...
About 8 million people rely on groundwater from the Mississippi embayment—Texas coastal uplands aquifer system for drinking water. The River Valley alluvial also provides water domestic use in rural areas but is of primary importance to region as a source irrigation. Irrigation withdrawals this are among largest Nation and play key role economy area, where annual crop sales total more than $7 billion. reliance both aquifers irrigation highlights long-term management sustain availability...
In 2001, the National Water-Quality Assessment (NAWQA) Program of U.S. Geological Survey initiated a series studies on transport anthropogenic and natural contaminants (TANC) to public-supply wells (PSWs). The main goal TANC project was better understand source, transport, receptor factors that control contaminant movement PSWs in representative aquifers United States. Regional- local-scale study areas were selected from within existing NAWQA units, including south-central Texas Edwards...
In 2001, the U.S. Geological Survey National Water-Quality Assessment Program collected water samples from 48 wells in southern High Plains as part of a larger scientific effort to broadly characterize and understand factors affecting quality aquifer across entire Plains. Water were primarily domestic Texas eastern New Mexico. Depths sampled ranged 100 500 feet, with median depth 201 feet. 34 445 feet below land surface, 134 Of 240 properties or constituents measured analyzed, 10 exceeded...
This report summarizes major findings about water quality in south-central Texas that emerged from an assessment conducted between 1996 and 1998 by the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program. Water is discussed terms of local regional issues compared to conditions found all 36 NAWQA study areas, called Study Units, assessed date. Findings also are explained context selected national benchmarks, such as those for drinking-water protection aquatic...
A study of the quality ground water beneath irrigated cropland was completed for northern and southern High Plains aquifer. Ground-water samples were collected from 30 water-table monitoring wells in agricultural land-use (NAL) area Nebraska 2004 29 (SAL) Texas 2003. The two areas represented different hydrogeologic settings. primary crops grown NAL corn soybeans, crop SAL cotton. Overall, pesticide fertilizer application rates larger area. Also, precipitation recharge greater area, depths...
ABSTRACT: A synthetic triangular hyetograph for a large data base of Texas rainfall and runoff is needed. represents the temporal distribution intensity at point or over watershed during storm. Synthetic hyetographs are estimates expected time design storm principally used in small hydraulic structure design. more than 1,600 observed cumulative that produced from 91 watersheds (generally less about 50 km 2 ) was to provide statistical parameters simple shaped model. The model provides an...
This report evaluates dissolved noble gas data, specifically helium-3 and helium-4, collected by the U.S. Geological Survey, in cooperation with San Antonio Water System, during 2002-03. Helium analyses are used to provide insight into sources of groundwater freshwater/saline-water transition zone segment Edwards aquifer. Sixty-nine samples were from 19 monitoring wells (categorized as fresh, transitional, or saline on basis solids concentration fluid-profile logging boreholes) arranged five...
The Geysers geothermal field in northern California, with about 2000-MW electrical capacity, is the largest world. Despite its importance as a resource and an example of vapor-dominated reservoir, very few complete geochemical analyses steam have been published (Allen Day, 1927; Truesdell others, 1987). This report presents data from 90 steam, gas, condensate samples wells California. Samples were collected between 1978 1991. Well attributes include sampling date, well name, location, total...
In 2006, a public-supply well in San Antonio, Texas, was selected for intensive study to assess the vulnerability of wells Edwards aquifer contamination by variety compounds. A local-scale, steady-state, three-dimensional numerical groundwater-flow model developed and used this evaluate movement water solutes from recharge areas well. Particle tracking compute flow paths advective traveltimes throughout area delineate contributing zone contribution The local-scale grid has finer vertical...
This fact sheet highlights findings from the vulnerability study of a public-supply well field in San Antonio, Texas. The consists six production wells that tap Edwards aquifer. Typically, one or two are pumped at time, yielding an average total 20-21 million gallons per day. Water samples were collected and monitoring installed along general directions flow to field. Samples contained some constituents concern for drinking-water quality, including nitrate; pesticide compounds atrazine,...
San Marcos Springs is the second largest spring in Texas and headwaters for River Marcos. Spring Lake (fig. 1) was built 1848 at site of a marsh formed by springs to provide hydropower mill. The originates from 15-acre lake flows approximately 4 river miles (mi) south its confluence with Blanco River. mean annual flow about 170 cubic feet per (ft3/s).
To provide data for the Texas Source-Water Assessment and Protection Program, U.S. Geological Survey conducted a synoptic survey of 48 public water-supply reservoirs 174 wells during 1999–2001. The surface-water samples were analyzed volatile organic compounds soluble pesticides. ground-water pesticides, as well nitrite plus nitrate nitrogen tritium. One or more detected in 75 percent 9 wells. Methyl tert-butyl ether was most frequently reservoirs, toluene pesticides 96 33 Atrazine its...
This newsletter describes a specific flooding event that affected large part of San Antonio and Austin, including Waller Creek.