using a geographic information system and statistics, we evaluated spatial distributions ofnitrate and chloride concentrations in groundwater in an area of north-central texas with agricultural activity,in addition to oil and natural gas exploration and production. data were compiled from 40 water wells sampledin 2007. nitrate concentrations in three wells exceeded the maximum contaminant level...

using a geographic information system and statistics, we evaluated spatial distributions ofnitrate and chloride concentrations in groundwater in an area of north-central texas with agricultural activity,in addition to oil and natural gas exploration and production. data were compiled from 40 water wells sampledin 2007. nitrate concentrations in three wells exceeded the maximum contaminant level...

The Texas fauna of the genus Anillinus Casey, 1918 includes three previously described species (A. affabilis (Brues), 1902, A. depressus (Jeannel), 1963 and A. sinuatus (Jeannel), 1963) and four new species here described: A. acutipennis Sokolov & Reddell, sp. n. (type locality: Fort Hood area, Bell County, Texas); A. comalensis Sokolov & Kavanaugh, sp. n. (type locality: 7 miles W of New Braun...

Nitrate-N (NO3 N) is one of the most pervasive contaminants in groundwater. Nitrate in groundwater exhibits long-term behavior due to complex interactions at multiple scales among various geophysical factors, such as sources of nitrate-N, characteristics of the vadose zone and aquifer attributes. To minimize contamination of nitrate-N in groundwater, it is important to estimate hot spots (>10 m...

First posted April 5, 2021 For additional information, contact: NAWQA Chief Scientist National Water-Quality Program U.S. Geological Survey 12201 Sunrise Valley Drive, MS 413 Reston, VA 20192-0002 Groundwater provides nearly 50 percent of the Nation’s drinking water. To help protect this vital resource, (USGS) Assessment (NAWQA) Project assesses groundwater quality in aquifers that are importan...

Multiple plumes of chlorinated organic compounds (PCE, TCE, and cis-1,2-DCE) are present above drinking water standards in groundwater underlying Camp Stanley Storage Activity (CSSA). One such plume has migrated off-post and is now impacting more than 20 drinking water wells within the Middle Trinity Aquifer. The off-post groundwater plume is defined by a series of traditional monitoring wells ...

The U.S. Geological Survey, in cooperation with San Antonio Water System, conducted a geophysical and geological study of the Cibolo Canyon development area, northeast Bexar County, Texas, to characterize hydrostratigraphic features and to map surface and subsurface hydrogeologic features of the Edwards aquifer. Capacitively-coupled (CC) resistivity and frequency-domain electromagnetic (FDEM) p...

[1] We present a robust optimization method for estimating aquifer storage parameters (specific yield or storativity) using the Gravity Recovery and Climate Experiment (GRACE) data, in situ well level observations, and other ancillary information. Uncertainty inherent in the remotely sensed and in situ time series can adversely affect the parameter estimation process and, in the worse case, mak...

a Medicinal Chemistry, Institute of Molecular Medicine, Trinity Centre for Health Sciences, Trinity College Dublin, St James's Hospital, Dublin 8, Ireland b School of Chemistry, SFI Tetrapyrrole Laboratory, Trinity College Dublin, Dublin 2, Ireland c Clinical Medicine, Institute of Molecular Medicine, Trinity Centre for Health Sciences, Trinity College Dublin, St James's Hospital, Dublin 8, Ire...