Distribution and Probable Sources of Nitrate in the Seymour Aquifer, North Central Texas, USA

Distribution and Probable Sources of Nitrate in the Seymour Aquifer, North Central Texas, USA

Access: Use of this item is restricted to the UNT Community.
Date: May 2001
Creator: Hillin, Clifford K.
Description: This study utilized GIS and statistical methods to map the spatial variability of nitrate and related groundwater constituents in 30 counties above the Seymour Aquifer, analyze temporal patterns of nitrate pollution, identify probable sources of pollution, and recommend water development strategies to minimize exposure to nitrate and reduce future aquifer contamination. Nitrate concentrations in excess of 44 mg/L (US EPA limit) were commonly observed in the Seymour Aquifer region, especially in the central agricultural belt. Data indicated that this is an ongoing problem in the Seymour Aquifer and that agricultural activity and rural septic systems are the likely sources of the nitrate. Inconclusive results emphasized the need for a more comprehensive spatial and temporal water quality monitoring.
Contributing Partner: UNT Libraries
Use of geographic information systems for assessing ground water pollution potential by pesticides in central Thailand

Use of geographic information systems for assessing ground water pollution potential by pesticides in central Thailand

Date: August 2002
Creator: Thapinta, Anat
Description: This study employed geographic information systems (GIS) technology to evaluate the vulnerability of groundwater to pesticide pollution. The study area included three provinces (namely, Kanchana Buri, Ratcha Buri, and Suphan Buri) located in the western part of central Thailand. Factors used for this purpose were soil texture, percent slope, primary land use, well depth, and monthly variance of rainfall. These factors were reclassified to a common scale showing potential to cause groundwater contamination by pesticides. This scale ranged from 5 to 1 which means high to low pollution potential. Also, each factor was assigned a weight indicating its influence on the movement of pesticides to groundwater. Well depth, the most important factor in this study, had the highest weight of 0.60 while each of the remaining factors had an equal weight of 0.10. These factors were superimposed by a method called “arithmetic overlay” to yield a composite vulnerability map of the study area. Maps showing relative vulnerability of groundwater to contamination by pesticides were produced. Each of them represented the degree of susceptibility of groundwater to be polluted by the following pesticides: 2,4-D, atrazine, carbofuran, dicofol, endosulfan, dieldrin & aldrin, endrin, heptachlor & heptachlor epoxide, total BHC, and total DDT. ...
Contributing Partner: UNT Libraries
Nitrate and Chloride Concentrations in Groundwater beneath a Portion ofn the Trinity Group Outcrop Zone, Texas

Nitrate and Chloride Concentrations in Groundwater beneath a Portion ofn the Trinity Group Outcrop Zone, Texas

Date: 2012
Creator: Hudak, Paul F.
Description: This article discusses a study in which the authors evaluated spatial distributions of nitrate and chloride concentrations in groundwater in an area of north-central Texas with agricultural activity, in addition to oil and natural gas exploration and activity.
Contributing Partner: UNT College of Arts and Sciences
Nitrate, Arsenic and Selenium Concentrations in The Pecos Valley Aquifer, West Texas, USA

Nitrate, Arsenic and Selenium Concentrations in The Pecos Valley Aquifer, West Texas, USA

Date: 2010
Creator: Hudak, Paul F.
Description: This article discusses nitrate, arsenic, and selenium concentrations in the Pecos Valley Aquifer in west Texas in the context of local geology and land use.
Contributing Partner: UNT College of Arts and Sciences
Spatio-temporal Variation of Nitrate Levels in Groundwater in Texas, 1970 to 2010

Spatio-temporal Variation of Nitrate Levels in Groundwater in Texas, 1970 to 2010

Date: December 2012
Creator: Rice, Susan C.
Description: This study looks at spatial variation of groundwater nitrate in Texas and its fluctuations at 10 year increments using data from the Texas Water Development Board. While groundwater nitrate increased in the Ogallala and Seymour aquifers across the time period, the overall rate in Texas appears to be declining as time progresses. However, the available data is limited. Findings show that a much more targeted, knowledge based strategy for sampling would not only reduce the cost of water quality analysis but also reduce the risk of error in these analyses by providing a more realistic picture of the spatial variation of problem contaminants, thereby giving decision-makers a clearer picture on how best to handle the reduction and elimination of problem contaminants.
Contributing Partner: UNT Libraries
Drinking Water Management Act

Drinking Water Management Act

Date: January 27, 2006
Creator: China (Republic : 1949- ). Huan jing bao hu shu
Description: This law was passed by the Republic of China (Taiwan) to safeguard public health by protecting drinking water resources from pollution by dumping, logging, industry, nuclear waste, ranching, recreation, mineral exploration and extraction, transportation, and other activities.
Contributing Partner: UNT Libraries
Development of a procedure to evaluate groundwater quality and potential sources of contamination in the East Texas Basin

Development of a procedure to evaluate groundwater quality and potential sources of contamination in the East Texas Basin

Access: Use of this item is restricted to the UNT Community.
Date: May 2001
Creator: Alderman, John H.
Description: This study contributes a procedure, based on data analysis and geostatistical methods, to evaluate the distribution of chemical ratios and differentiate natural and anthropogenic contaminant sources of groundwater quality in the East Texas Basin. Four aquifers were studied, Sparta, Queen City, Carrizo and Wilcox. In this study, Carrizo- Wilcox is considered as one aquifer, and Sparta-Queen City as another. These aquifers were divided into depth categories, 0-150 feet for Sparta-Queen City and 300-600 feet and 600-900 feet for Carrizo-Wilcox in order to identify individual sources of contamination. Natural sources include aquifer mineral make up, salt domes and lignite beds. Major anthropogenic sources include lignite and salt dome mining and oil-gas production. Chemical ratios selected were Na/Cl, Ca/Cl, Mg/Cl, SO4/Cl, (Na+Cl)/TDS, SO4/Ca and (Ca+Mg)/(Na+K). Ratio distributions and their relationships were examined to evaluate physical-chemical processes occurring in the study area. Potential contaminant sources were used to divide the Basin into three areas: Area 1 to the east, Area 2 in the west and Area 3 in the center. Bivariate analysis was used to uncover differences between the areas. The waters in Area 1 are potentially impacted primarily from oil field waters. Sources present in Area 2 include lignite beds and oil ...
Contributing Partner: UNT Libraries
Surface Water and Groundwater Hydrology of Borrow-Pit Wetlands and Surrounding Areas of the Lewisville Lake Environmental Learning Area, Lewisville, Texas

Surface Water and Groundwater Hydrology of Borrow-Pit Wetlands and Surrounding Areas of the Lewisville Lake Environmental Learning Area, Lewisville, Texas

Date: August 2004
Creator: Dodd-Williams, Lynde L.
Description: The focus of this study was to characterize the surface water and groundwater hydrology of borrow-pit wetlands located within the borders of the Lewisville Lake Environmental Learning Area (LLELA), east of the Elm Fork of the Trinity River. The wetlands were excavated into alluvial deposits downstream of the Lewisville Lake Dam. Both surface water and groundwater contribute to the hydro-period of the borrow-pit wetlands. Nearby marshes exhibit characteristics of groundwater discharge. Salinity in groundwater-fed wetlands could affect establishment of vegetation, as suggested from plant surveys. Surface water input from storm events dilutes salinity levels. Management of LLELA wetlands should include long-term evaluation of hydrology and plantings to enhance habitat. Plans for additional wetlands should consider both surface water and groundwater inputs.
Contributing Partner: UNT Libraries
Science and Technology to Support Fresh Water Availability in the United States

Science and Technology to Support Fresh Water Availability in the United States

Date: November 2004
Creator: National Science and Technology Council (U.S.). Committee on Environment and Natural Resources.
Description: This report describes issues regarding water use, conservation, and management. Many parts of the United States are expected to face water shortages in the near future.
Contributing Partner: UNT Libraries
[Letters from Friends of the Valley to Clarke Dice - August 2005]

[Letters from Friends of the Valley to Clarke Dice - August 2005]

Date: August 2005
Creator: Friends of the Valley
Description: Letters from anonymous Friends of the Valley to Clarke Dice regarding development in Indian Wells Valley, California.
Contributing Partner: UNT Libraries Government Documents Department
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