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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, 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
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
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
Public Health Service Act

Public Health Service Act

Date: 1974
Creator: United States. Congress
Description: The Safe Drinking Water Act (SDWA) was established to protect the quality of drinking water in the U.S. This law focuses on all waters actually or potentially designed for drinking use, whether from above ground or underground sources. The Act authorizes EPA to establish minimum standards to protect tap water and requires all owners or operators of public water systems to comply with these primary (health-related) standards. The 1996 amendments to SDWA require that EPA consider a detailed risk and cost assessment, and best available peer-reviewed science, when developing these standards. State governments, which can be approved to implement these rules for EPA, also encourage attainment of secondary standards (nuisance-related). Under the Act, EPA also establishes minimum standards for state programs to protect underground sources of drinking water from endangerment by underground injection of fluids.
Contributing Partner: UNT Libraries
A New Approach to Texas Groundwater Management: An Environmental Justice Argument to Challenge the Rule of Capture

A New Approach to Texas Groundwater Management: An Environmental Justice Argument to Challenge the Rule of Capture

Date: December 2005
Creator: Purvis, Jody
Description: Texas is the last remaining state to utilize the rule of capture, a doctrine based on English Common Law, as a means of regulating groundwater resources. Many of the western states originally used the rule of capture to regulate their groundwater resources, but over time, each of these states replaced the rule of capture with other groundwater laws and regulations. The Texas Water Development Board (TWDB) State Water Plan, Water for Texas-2002, warned Texans if current water usage and laws do not change, there will be an unmet need of 7.5 million acre-feet of water annually by 2050. This caused individuals in state and local government to begin asking the question, "How are we going to meet our future water needs?" In the search for a solution to the water shortage problem people have divided themselves into two groups: one wants to consider the implementation of water conservation measures to reduce per capita water use in order to meet future demands; while the other group wants to spend millions of dollars to build reservoirs and dams along with laying thousands of miles of pipeline to move water around the state. The fact that Texas has yet to come up with ...
Contributing Partner: UNT Libraries
Water Resources

Water Resources

Date: June 26, 2014
Creator: Rodriguez, Kathia
Description: Lesson plan containing a collection of activities and resources regarding water resources that meet state education standards and national sustainability standards for the 7th grade level.
Contributing Partner: UNT Office of Sustainability
Spatial Distribution of Solutes in Aquifer Outcrop Zones along the Brazos River, East-Central Texas

Spatial Distribution of Solutes in Aquifer Outcrop Zones along the Brazos River, East-Central Texas

Date: Summer 2011
Creator: Hudak, Paul F.
Description: Article discussing the spatial distribution of solutes in aquifer outcrop zones along the Brazos River, East-Central Texas.
Contributing Partner: UNT College of Arts and Sciences
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
Performance Comparison of Passive Structures with Multiple Gates and Funnels for Capturing Contaminated Groundwater

Performance Comparison of Passive Structures with Multiple Gates and Funnels for Capturing Contaminated Groundwater

Date: September 2007
Creator: Hudak, Paul F.
Description: This article describes the evaluation of the capability of passive interceptors with multiple gates for directing the flow of contaminated groundwater.
Contributing Partner: UNT College of Arts and Sciences
Efficiency Comparison of Variably-Spaced, Non-Pumped Wells for Filtering Polluted Groundwater

Efficiency Comparison of Variably-Spaced, Non-Pumped Wells for Filtering Polluted Groundwater

Date: 2009
Creator: Hudak, Paul F.
Description: This article investigates the capability of variably-spaced arrays of non-pumped wells, filled with reactive media, to filter a hypothetical contaminant plume.
Contributing Partner: UNT College of Arts and Sciences
Nitrate and Chloride Concentrations in Groundwater beneath a Portion of the Trinity Group Outcrop Zone, Texas

Nitrate and Chloride Concentrations in Groundwater beneath a Portion of 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
Groundwater Data Package for Hanford Assessments

Groundwater Data Package for Hanford Assessments

Date: January 2006
Creator: Thorne, Paul D.; Bergeron, Marcel P.; Williams, Mark D. & Freedman, Vicky L.
Description: This report presents data and interpreted information that supports the groundwater module of the System Assessment Capability (SAC) used in Hanford Assessments. The objective of the groundwater module is to predict movement of radioactive and chemical contaminants through the aquifer to the Columbia River or other potential discharge locations. This data package is being revised as part of the deliverables under the Characterization of Systems Project (#49139) aimed at providing documentation for assessments being conducted under the Hanford Assessments Project (#47042). Both of these projects are components of the Groundwater Remediation and Closure Assessments Projects, managed by the Management and Integration Project (#47043).
Contributing Partner: UNT Libraries Government Documents Department
Ecology and Recolonization of Benthic Macroinvertebrates in a Groundwater-dependent Stream in North Central Texas During a Supra-seasonal Drought

Ecology and Recolonization of Benthic Macroinvertebrates in a Groundwater-dependent Stream in North Central Texas During a Supra-seasonal Drought

Date: May 2012
Creator: Burk, Rosemary A.
Description: Extreme climatic events such as droughts are known to eliminate aquatic biota and alter community structure and function. Perennial headwater springs provide important drought refugia to benthic macroinvertebrates and an important source of colonists via drift or aerial adults to intermittent streams post-drought. During a supra-seasonal drought in North-central Texas summer and fall 2006, benthic macroinvertebrates from persistent groundwater-dependent macrohabitats of varying hydrological connectivity and riparian shading were studied: perennial riffles, connected pools, shaded disconnected pools, and full sun disconnected pools. Riffles were a distinct habitat with significantly higher taxa richness, proportion of lotic taxa, diversity and evenness than other macrohabitats. Macrohabitats were found to be important refugia for 106 benthic macroinvertebrates and 4 microcrustacean taxa. Throughout the extreme drought, perennially flowing habitats were refugia to 19 taxa (17.9% total taxa) not collected in disconnected pools. Shaded disconnected pools contained lotic taxa not previously known to be able to complete their lifecycles in lentic habitats, emphasizing the importance of groundwater effluent and shading. With the resumption of flow at a downstream intermittent site of Ash Creek in mid-October 2006, an annual recolonization study was conducted comparing the perennial headwaters’ benthic macroinvertebrate taxa richness, densities and community ecology with the downstream ...
Contributing Partner: UNT Libraries
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