Groundwater recharge and chemical evolution in the southern High Plains of Texas, USA (original) (raw)
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Environmental Earth Sciences, 2010
This paper expands significantly on the majorion geochemical characterization, evolution, and differentiation of groundwater in the Presidio-Redford Bolson (PRB) Aquifer of Texas as presented in Chowdhury et al. (2008). For 19 groundwater samples from the PRB Aquifer, the author calculated major cation-anion balance errors, equilibrium carbon dioxide partial pressure values and saturation indices for selected minerals. Comparison of major-ion analyses for groundwater from basin margin wells with those for basin center wells is documented and illustrated with ion-concentration maps and Piper and Stiff diagrams and reveals significant increases in concentrations of chloride, sulfate and sodium coupled with notable decrease of calcium in bolson-center well samples. These geochemical changes suggest dissolution of aquifer minerals and cation exchange as groundwater migrates downgradient to the bolson center. The US Geological Survey (USGS) computer code, NETPATH, was used to interpret probable net geochemical mass-balance reactions that potentially have occurred within the PRB Aquifer along groundwater flowpaths from bolson margin to bolson center. For all four upgradient-downgradient well pairs studied, at least three NETPATH models contain cation exchange values; calcium is being exchanged for sodium. The Rio Grande Alluvium Aquifer and Rio Grande River are notably minor sources of recharge to the PRB Aquifer, based on Chowdhury et al. (2008) and geochemical evaluations of this study.
2009
Sustainable management of groundwater resources requires sufficient knowledge of the distribution of fresh and saline groundwater and the processes affecting saltwater intrusion that may influence the beneficial use of groundwater. A hydrogeologic investigation that coupled various chemical and isotopic tracers, including 3 H/ 3 He, 14 C, δD, δ 18 O, 87 Sr/ 86 Sr, and δ 11 B, with the physical characteristics of the aquifer was conducted to determine source waters, the origin of saltwater and its influence through cross-formational flow, and water-rock interactions in the Southern High Plains aquifer along the Western Caprock Escarpment. Sub-aquifers or local flow systems are present along the Western Caprock Escarpment, and the study site's local flow system drains a Na-Cl, high dissolved solids (2,000 to 9,500 mg/L) groundwater from the escarpment until it mixes with a regional aquifer or regional flow system that is more oxygenated and a mixed cation-HCO 3 water type with low dissolved solids (390 to 520 mg/L). The local flow system contains old water (5,500 to 21,000 years) that is similar in age and composition to the underlying, upper Dockum aquifer (Na-Cl water type, 970 to 13,000 mg/L dissolved solids, 12,000 to 27,000 years). The δD and δ 18 O values for the local flow system (-71.74 to -47.96‰
The High Plains aquifer underlies about 174,000 square miles in parts of eight states, including about 7,100 square miles in northwestern Oklahoma (fig. 1). This aquifer consists of the saturated part of the Ogallala Formation and saturated materials of Quaternary Age that are hydraulically connected to the Ogallala. The High Plains aquifer in northwestern Oklahoma is the primary source of water to an important agricultural region. Most water is withdrawn from the aquifer for irrigating wheat and other grain crops, with the remainder used for livestock (primarily cattle and swine), municipal, and domestic needs. Historically, water from precipitation was thought to take hundreds or thousands of years to reach the water table because the depth of the water table is greater than 100 feet over most of the aquifer and the low-permeability beds in the Ogallala would impede downward flow. It also was thought that land uses would take a similar period of time to affect water quality in the aquifer. The U.S. Geological Survey, in cooperation with the Oklahoma Water Resources Board, conducted a reconnaissance investigation that included determination of recharge ages and water quality in early 1999. Samples were collected from 12 domestic wells (fig. 1), ranging in depth from 25 to 300 feet. Recharge age, which indirectly indicates travel time from the land surface to the water table, was determined by analyses of isotopes of hydrogen and helium, or carbon. Water samples also were analyzed for physical properties, major ions, trace metals, and nutrients.
University of Texas at Austin Dissertation, 2009
The Barton Springs Segment, part of the karstic Edwards aquifer in Central Texas, is a Sole Source aquifer, is habitat to rare karst species, and provides water to a well-loved municipal swimming pool, yet its hydrogeologic properties remain insufficiently understood. This study examines surface/subsurface geology, site-scaled precipitation budget using precipitation gauges, eddy-covariance tower, flumes, and soil-moisture sensors to calculate groundwater recharge, groundwater tracing, cave geology, aquifer testing, and nature of biases in the objective analysis of the Edwards Aquifer. In particular, down-dropped fault blocks create groundwater gradients to the southeast, perpendicular to fault trends, that influence flow in the Edwards outcrop area. Upland internal drainage basins were found to be extremely efficient at conveying recharge to the underlying aquifer. The maturity of natural internal drainage sinkholes can be measured by its bowl volume, which grows in proportion to the catchment area it captures. A 19-hectare internal drainage basin, HQ Flat sinkhole, was monitored for rainfall, evapotranspiration, soil moisture, and discrete runoff to the cave drain. During a 505-day period, 5.5% of measured rainfall entered the cave drain as discrete recharge, 26% of measured rainfall infiltrated through soils on the slopes, and the remaining 68% was measured as evapotranspiration. This amount of upland infiltration is consistent with infiltration measurements in other karst areas and is much larger than the less than 1% upland recharge of rainfall that was previously estimated. A chloride mass balance indicates that at the adjacent Tabor research site, roughly 50% of rainfall infiltrates to a 6-meter depth. Dye-tracing and pump tests demonstrated that primary and secondary groundwater flow paths are the major influence on transmissivity within the Barton Springs Segment. Groundwater tracing breakthroughs reveal very high advection and relatively low dispersion. Drawdown response to pump tests indicates a very high degree of anisotropy, controlled by location of groundwater flow paths. Overall, the Barton Springs Segment is a mature karst aquifer with highly developed rapid, discrete network for both recharge and groundwater-flow.
Journal of Hydrology, 2010
s u m m a r y A two and a half year study of two adjacent watersheds at the Honey Creek State Natural Area (HCSNA) in central Texas was undertaken to evaluate spatial and temporal variations in springwater geochemistry, geochemical evolution processes, and potential effects of brush control on karst watershed hydrology. The watersheds are geologically and geomorphologically similar, and each has springs discharging into Honey Creek, a tributary to the Guadalupe River. Springwater geochemistry is considered in a regional context of aquifer components including soil water, cave dripwater, springwater, and phreatic groundwater. Isotopic and trace element variability allows us to identify both vadose and phreatic groundwater contributions to surface water in Honey Creek. Spatial and temporal geochemical data for six springs reveal systematic differences between the two watersheds. Springwater Sr isotope values lie between values for the limestone bedrock and soils at HCSNA, reflecting a balance between these two primary sources of Sr. Sr isotope values for springs within each watershed are consistent with differences between soil compositions. At some of the springs, consistent temporal variability in springwater geochemistry (Sr isotopes, Mg/Ca, and Sr/Ca values) appears to reflect changes in climatic and hydrologic parameters (rainfall/recharge) that affect watershed processes. Springwater geochemistry was unaffected by brush removal at the scale of the HCSNA study. Results of this study build on previous regional studies to provide insight into watershed hydrology and regional hydrologic processes, including connections between surface water, vadose groundwater, and phreatic groundwater.
Zona Citrícola is an important area for Mexico due to its citriculture activity. Situated in a sub-humid to humid climate adjacent to the Sierra Madre Oriental, this valley hosts an aquifer system that represents sequences of shales, marls, conglomerates, and alluvial deposits. Groundwater flows from mountainous recharge areas to the basin-fill deposits and provides base flows to supply drinking water to the adjacent metropolitan area of Monterrey. Recent studies examining the groundwater quality of the study area urge the mitigation of groundwater pollution. The objective of this study was to characterize the physical and chemical properties of the groundwater and to assess the processes controlling the groundwater's chemistry. Correlation was used to identify associations among various geochemical constituents. Factor analysis was applied to identify the water's chemical characteristics that were responsible for generating most of the variability within the dataset. Hierarchical cluster analysis was employed in combination with a post-hoc analysis of variance to partition the water samples into hydrochemical water groups: recharge waters (Ca-HCO 3 ), transition zone waters (Ca-HCO 3 -SO 4 to Ca-SO 4 -HCO 3 ) and discharge waters (Ca-SO 4 ). Inverse geochemical models of these groups were developed and constrained using PHREEQC to elucidate the chemical reactions controlling the water's chemistry between an initial (recharge) and final water. The primary reactions contributing to salinity were the following: (1) water-rock interactions, including the weathering of evaporitic rocks and dedolomitization; (2) dissolution of soil gas carbon dioxide; and (3) input from animal/human wastewater and manure in combination with by denitrification processes. Contributions from silicate weathering to salinity ranged from less important to insignificant. The findings suggest that it may not be cost-effective to regulate manure application to mitigate groundwater pollution.
2021
The intersection of an increasing population, climate change, pollution, and over allocation of water continue to place additional strain on groundwater resources in arid regions. Groundwater in arid environments is particularly susceptible to overuse, and therefore a thorough understanding of groundwater sources and its contribution to sensitive ecosystems is vital. Unaweep Canyon, in the arid region of Colorado's western slope, is a geologically unique site that harbors a buried paleovalley. The modern valley contains up to ~500 m of sediment fill comprising unconsolidated lacustrine, fluvial, and mass-wasting deposits, as well as possible lithified sedimentary rocks. We hypothesize that the unconsolidated layers in Unaweep Canyon aquifer are not hydrogeochemically linked and represent different, unique sources of groundwater. Our study focused on integrating published geologic information, geophysical data, and seasonal geochemical properties of groundwater and surface water to delineate multiple sources of water for both human and ecosystem needs. Several streams, seeps, Precambrian bedrock spring aquifers, and several domestic wells were sampled for metals, anions, and stable isotopes (18 O and 2 H) during spring,
Geological Society of America Bulletin, 2010
recharge, rock-water interactions, and mixing of a buried bedrock valley in the midwestern United States: Implications for Chemical and isotopic indicators of groundwater evolution in the basal sands Email alerting services articles cite this article to receive free e-mail alerts when new www.gsapubs.org/cgi/alerts click Subscribe America Bulletin to subscribe to Geological Society of www.gsapubs.org/subscriptions/ click Permission request to contact GSA http://www.geosociety.org/pubs/copyrt.htm#gsa click official positions of the Society. citizenship, gender, religion, or political viewpoint. Opinions presented in this publication do not reflect presentation of diverse opinions and positions by scientists worldwide, regardless of their race, includes a reference to the article's full citation. GSA provides this and other forums for the the abstracts only of their articles on their own or their organization's Web site providing the posting to further education and science. This file may not be posted to any Web site, but authors may post works and to make unlimited copies of items in GSA's journals for noncommercial use in classrooms requests to GSA, to use a single figure, a single table, and/or a brief paragraph of text in subsequent their employment. Individual scientists are hereby granted permission, without fees or further
Sustainable management of groundwater resources requires sufficient knowledge of the distribution of fresh and saline groundwater and the processes affecting saltwater intrusion that may influence the beneficial use of groundwater. A hydrogeologic investigation that coupled various chemical and isotopic tracers, including 3 H/ 3 He, 14 C, δD, δ 18 O, 87 Sr/ 86 Sr, and δ 11 B, with the physical characteristics of the aquifer was conducted to determine source waters, the origin of saltwater and its influence through cross-formational flow, and water-rock interactions in the Southern High Plains aquifer along the Western Caprock Escarpment. Sub-aquifers or local flow systems are present along the Western Caprock Escarpment, and the study site's local flow system drains a Na-Cl, high dissolved solids (2,000 to 9,500 mg/L) groundwater from the escarpment until it mixes with a regional aquifer or regional flow system that is more oxygenated and a mixed cation-HCO 3 water type with low dissolved solids (390 to 520 mg/L). The local flow system contains old water (5,500 to 21,000 years) that is similar in age and composition to the underlying, upper Dockum aquifer (Na-Cl water type, 970 to 13,000 mg/L dissolved solids, 12,000 to 27,000 years). The δD and δ 18 O values for the local flow system (-71.74 to -47.96‰