Groundwater最新文献

{"title":"The Essential Role of Aquitard Boundaries in Geochemical Outcomes for Public Supply Wells","authors":"Noah R. Heller,&nbsp;Marina Feraud,&nbsp;Chris Bonds,&nbsp;James D. Bohan,&nbsp;Christian Leach,&nbsp;Kimberly A. Miles","doi":"10.1111/gwat.70035","DOIUrl":"10.1111/gwat.70035","url":null,"abstract":"<p>Many public supply wells (PSWs) fail because their water chemistry does not meet regulatory standards, despite pilot hole water quality testing suggesting compliance. This is partly attributed to conventional testing that focuses on the mid-section of permeable zones, excluding low-permeability units or aquitards. The main goal is to prove yield, so groundwater is sampled within the tested interval for efficiency. Clay boundaries are typically excluded from zone testing because of low expected yields, but they may harbor elevated concentrations of constituents of concern. Well discharge concentrations may thus be non-compliant due to the blend of groundwater from permeable, high-yield zones and less permeable, elevated concentration zones. We evaluated flow and chemistry across the screens of 143 wells in California and Nevada, identifying the screen intervals with maximum arsenic, iron, manganese, and nitrate concentrations. We examined the relationship between sediment type, flow contribution, and maximum concentrations, focusing on the influence of aquitard boundaries and interbedded sequences on geochemical outcomes. Maximum concentrations occurred mostly (73–84%) in well screens associated with interbedded or coarse sediments with an aquitard boundary. Intervals with aquitard boundaries had higher arsenic concentrations (<i>p</i> = 0.02). In non-compliant wells, 64–69% of the maximum metal concentrations were sourced from fine-grained and interbedded sediments, warranting their inclusion in water quality zone testing. Approaches that may provide the geochemical resolution to determine the distance between aquitard boundaries and well screens are suggested to minimize the risk of constructing non-compliant PSWs that then require treatment.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"64 1","pages":"64-76"},"PeriodicalIF":2.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145710710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"History and Results of U.S./Mexico Groundwater Data Exchange Programs in the Paso del Norte Region, 1897 to 2022","authors":"Barry J. Hibbs","doi":"10.1111/gwat.70037","DOIUrl":"10.1111/gwat.70037","url":null,"abstract":"<p>The transboundary Hueco Bolson aquifer is the primary water supply for El Paso, Texas, and Ciudad Juárez, Mexico as well as U.S. Army Fort Bliss and smaller cities in Texas and Mexico. Binational groundwater data exchanges between the United States and Mexico that have focused on the aquifer have evolved over more than a century, shaped by scientific, political, and social dynamics. The history can be viewed through distinct periods. Efforts to understand the groundwater resource began with early reconnaissance surveys and have evolved through successive efforts to refine the characterization of groundwater flowpaths, residence times, surface water–groundwater interactions, and aquifer salinization. Lessons from these efforts highlight the importance of perseverance, mutual respect, and formal agreements, such as the 1999 memorandum between El Paso Water Utilities and the Junta Municipal de Agua y Saneamiento de Juárez, in sustaining long-term cooperation. The accumulated datasets chronicle the evolution of hydrogeologic conceptual and mathematical models while providing a foundation for ongoing research, sustainable water-use strategies, and the long-term stewardship of the Hueco Bolson aquifer shared by El Paso and Ciudad Juárez. The Hueco Bolson case demonstrates how long-term, cooperative data collection can improve scientific understanding and management of complex transboundary aquifer systems.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"64 1","pages":"103-124"},"PeriodicalIF":2.0,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145673334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Society News","authors":"","doi":"10.1111/gwat.70026","DOIUrl":"https://doi.org/10.1111/gwat.70026","url":null,"abstract":"","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 6","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145601179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrostatic Pressure Effect on the Transport of Fluoride in a Loose-Pore Geothermal Reservoir","authors":"Li Zhao,&nbsp;Hongbo Hu,&nbsp;Qing Zhang,&nbsp;Mingfei Xing,&nbsp;Yifei Liu,&nbsp;Wangxu Zhou","doi":"10.1111/gwat.70032","DOIUrl":"10.1111/gwat.70032","url":null,"abstract":"<p>The concentration of fluoride (F⁻) in many geothermal waters worldwide exceeds the World Health Organization's drinking water guideline of 1.5 mg/L, highlighting a widespread water quality issue in geothermal systems. It is essential to predict the mobility of F⁻ in geothermal reservoirs compared to that of chloride (Cl⁻). Column experiments were conducted at 45°C under hydrostatic pressures from atmospheric pressure to 12 MPa to simulate geothermal reservoir conditions, with the computer code CXTFIT 2.1 used to fit the data and determine transport and adsorption parameters of Cl⁻ and F⁻. The effect of hydrostatic pressure on F⁻ transport was evaluated. Results showed that the Convection–Dispersion Equation (CDE) accurately fits the breakthrough curves of Cl⁻ and higher pressures enhance its dispersion transport. In contrast, F⁻ transport under atmospheric pressure shows rate-limited non-equilibrium, with the Two-Site Model (TSM) fitting F⁻ curves better. However, when pressure exceeds 6 MPa, equilibrium adsorption becomes more pronounced, and the equilibrium CDE better characterizes F⁻ transport. Higher pressure also increases the retardation factor (<i>R</i>) of F⁻, suggesting more instantaneous adsorption sites under these conditions. The release of hydroxide (OH⁻) during F⁻ adsorption increases pH values in the effluent notably. Moreover, greater pH fluctuations occur with increasing pressure due to the enhanced adsorption of F⁻ by the packed matrix. The findings would be helpful for understanding the solute transport and adsorption mechanism of fluoride under varying hydrostatic pressures in groundwater and geothermal systems.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 6","pages":"889-901"},"PeriodicalIF":2.0,"publicationDate":"2025-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145544616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modernizing Deep Groundwater Testing: Rapid Stacked-Dynamic Profiling with Long Screened Test Wells","authors":"Noah R. Heller,&nbsp;Marina Feraud,&nbsp;Christian Kropf,&nbsp;John Izbicki,&nbsp;Frederick D. Day-Lewis,&nbsp;Kimberly A. Miles,&nbsp;Miles L. Koehler,&nbsp;Stefan McLin","doi":"10.1111/gwat.70030","DOIUrl":"10.1111/gwat.70030","url":null,"abstract":"<p>The tracer flowmeter and depth-dependent sampler (TFDDS) has been used to characterize flow and chemistry in hundreds of public supply wells. The TFDDS surveys address production and water quality compliance issues for utilities facing mounting treatment costs. Surveyed wells often show a stratified distribution for constituents of concern that were underestimated and poorly discretized using conventional zone testing in the pilot hole. Elevated concentrations of metals, semimetals, and radionuclides typically occurring at or near lithologic boundaries between fine- and coarse-grained sediments are missed since the primary focus of the zone test is to estimate the yield of the permeable sediments that are centered within a coarse unit. To minimize the risk of constructing new wells that fail to produce compliant drinking water relative to regulatory standards, we propose a new approach that vertically stacks flow and mass balance chemistry profiling of long screened test wells (LSTWs) under pumping conditions prior to installing the more costly public supply well. This approach integrates the TFDDS with a spectrum of drilling methods to rapidly provide hydraulic and chemistry data. A detailed distribution of anthropogenic and geogenic constituents within the saturated zones is produced, characterizing both permeable sediments and contaminant-laden boundaries between finer- and coarser-grained deposits. Applying this high-resolution data to well design leads to informed predictions on whether the new well will be compliant. Two case studies are presented, one for public supply well design and the other for managed aquifer recharge.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 6","pages":"830-845"},"PeriodicalIF":2.0,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145508613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thank You for Your Service","authors":"Kenneth R. Bradbury","doi":"10.1111/gwat.70031","DOIUrl":"10.1111/gwat.70031","url":null,"abstract":"&lt;p&gt;Earlier this year the US President announced a new executive action to remove civil service protections from thousands of federal employees, with the goal of empowering “… &lt;i&gt;federal agencies to swiftly remove employees in policy-influencing roles for poor performance, misconduct, corruption, or subversion of Presidential directives, without lengthy procedural hurdles&lt;/i&gt;” (https://www.whitehouse.gov/fact-sheets/2025/04/fact-sheet-president-donald-j-trump-creates-new-federal-employee-category-to-enhance-accountability/, accessed 4/20/25). Also earlier this year, most federal workers received a “fork in the road” memo essentially encouraging them to resign and take a buyout with no assurance of future job security (https://www.axios.com/2025/01/28/trump-federal-workers-quit-severance, accessed 10/23/25). More recently, the Interior Department “… said it plans to fire some 2050 employees, including 272 at the National Park Service (NPS), 335 at the U.S. Geological Survey (USGS), 143 from the Fish and Wildlife Service and 474 at the Bureau of Land Management (BLM)” (https://thehill.com/policy/energy-environment/5566157-trump-cuts-national-park-service-fish-wildlife-land-management-geological-survey/, accessed 10/23/25).&lt;/p&gt;&lt;p&gt;These policies and cuts are consistent with and even reinforce a too-common and erroneous perception among some segments of society that public employees are unneeded, overpaid, inefficient, lazy, incompetent, partisan, or even corrupt. Those of us who depend on the work of public agencies must speak up and remind ourselves, the public, and our politicians, of the high value of the work that they do and the contributions they make to the Nation and the world.&lt;/p&gt;&lt;p&gt;Public employees have made vast contributions to the hydrologic sciences over the past decades. Think of just a few of the most important names in US (and, indeed, international) hydrogeology: C.V. Theis, O.E. Meinzer, Luna B. Leopold, John D. Bredehoeft, Thomas Prickett; all spent significant parts of their careers in public service with the US Geological Survey or state agencies where they developed many of the fundamental principles of groundwater science we routinely use today (Clebsch &lt;span&gt;1993&lt;/span&gt;; Fryar &lt;span&gt;2007&lt;/span&gt;; Hunt and Meine &lt;span&gt;2012&lt;/span&gt;; Konikow et al. &lt;span&gt;2023&lt;/span&gt;; Wehrmann &lt;span&gt;2008&lt;/span&gt;). More recently other USGS scientists developed many of the numerical modeling applications that are now used by hydrogeologists around the world. In short, the contributions of public hydrologic scientists in recent years span the whole discipline of hydrogeology and beyond. And these individuals communicate their findings and ideas to the world through numerous &lt;i&gt;publicly available&lt;/i&gt; reports and presentations.&lt;/p&gt;&lt;p&gt;Over my professional career I have interacted and worked with literally hundreds of federal and state employees and their organizations. Have I seen examples of inefficiency? Sure, I have seen a bit of that, and I have had oc","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 6","pages":"816-817"},"PeriodicalIF":2.0,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ngwa.onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.70031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145484012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Navigating the Growing Prospects and Growing Pains of Managed Aquifer Recharge","authors":"Dave Owen,&nbsp;Helen E. Dahlke,&nbsp;Andrew T. Fisher,&nbsp;Ellen Bruno,&nbsp;Michael Kiparsky","doi":"10.1111/gwat.70029","DOIUrl":"10.1111/gwat.70029","url":null,"abstract":"<p>Increasing water demands and declining groundwater levels have led to rising interest in managed aquifer recharge. That interest is growing in the United States—the focus of this article—and elsewhere. Increasing interest makes sense; managed aquifer recharge can reduce water-supply challenges and provide environmental benefits, sometimes with lower costs than alternative water-management approaches. But managed aquifer recharge also faces growing pains, which will make it difficult for projects to scale up and may limit the benefits provided by those projects that do go forward. Some of the problems arise from the challenges of finding physically suitable locations for managed aquifer recharge; many derive from economics, public policy, and law; and some derive from ways in which managed aquifer recharge could exacerbate traditional equity challenges of water management. But as we explain, there also are potential solutions to these challenges, and the future success of managed aquifer recharge will likely depend on the extent to which these solutions are adopted.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 6","pages":"819-827"},"PeriodicalIF":2.0,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ngwa.onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.70029","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145460639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ArchPy and MODFLOW: Toward a General Integration of Heterogeneity into Groundwater Models","authors":"Ludovic Schorpp,&nbsp;Nina Egli,&nbsp;Julien Straubhaar,&nbsp;Philippe Renard","doi":"10.1111/gwat.70028","DOIUrl":"10.1111/gwat.70028","url":null,"abstract":"<p>Groundwater models are important and useful tools for answering scientific and technical questions about the quantity and quality of groundwater, as well as for making critical management decisions. However, the heterogeneity of subsurface properties, such as hydraulic conductivity, is known to play a central role in groundwater flow and transport; therefore, its accurate quantification and incorporation into the groundwater workflow are critical. This paper presents a novel tool, <i>ArchPy2Modflow</i>, that efficiently combines a stochastic geological generator, <i>ArchPy</i>, with a groundwater flow software, <i>MODFLOW</i>. <i>ArchPy2Modflow</i> provides a rapid and practical way to convert and link any ArchPy model to a new (or existing) MODFLOW model, where any <i>MODFLOW</i> spatial parameter (such as porosity, hydraulic conductivity, or storativity) can be obtained from an <i>ArchPy</i> property, which is then upscaled according to the <i>MODFLOW</i> grid. <i>ArchPy2Modflow</i> offers several different options for selecting the appropriate MODFLOW grid: using the same grid as in the ArchPy model, defining each ArchPy geological unit as a MODFLOW layer, coarsening the grid by a certain factor, or directly using an existing MODFLOW grid. This flexibility enables users to adapt their models to suit their needs and constraints. The usefulness and practicality of the new tool are demonstrated by a synthetic example considering flow and transport in a heterogeneous aquifer, while the impact of a particular grid selection on the simulations is demonstrated.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 6","pages":"902-916"},"PeriodicalIF":2.0,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ngwa.onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.70028","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145403258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Alternative Mechanism of Land Subsidence: Osmotic Effects Due to Seawater Intrusion","authors":"Haipeng Guo,&nbsp;Lichun Wang,&nbsp;Xiaowen Lv,&nbsp;Meng Huang,&nbsp;Xueping Xi","doi":"10.1111/gwat.70027","DOIUrl":"10.1111/gwat.70027","url":null,"abstract":"<p>Land subsidence is widely present across the globe and brings catastrophic hazards. The well-acknowledged mechanism of subsidence is groundwater pumping, which leads to the reduction of hydraulic head and hence increases the effective stress, resulting in the vertical compaction of unconsolidated sediment. Here, we propose a hypothesis that subsidence in the coastal areas might be caused by osmotic effects, given the presence of seawater intrusion. The hypothesis is corroborated by simulating fluid flow, solute transport, and elastic deformation of multi-layered aquifer-aquitard systems. The simulations potentially cover a variety of natural environments by varying concentration, hydraulic head, thickness of aquitard, and hydraulic conductivity. We find that osmotic effects due to seawater intrusion play a non-negligible role in controlling subsidence in our studied cases, suggesting that future work on subsidence in areas impacted by seawater intrusion should fully incorporate osmotic effects to improve our understanding and prediction of subsidence.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"64 1","pages":"77-89"},"PeriodicalIF":2.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145282354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MF6-ADJ: A Non-Intrusive Adjoint Sensitivity Capability for MODFLOW 6","authors":"Mohamed Hayek,&nbsp;Jeremy T. White,&nbsp;Katherine H. Markovich,&nbsp;Joseph D. Hughes,&nbsp;Marsh Lavenue","doi":"10.1111/gwat.70025","DOIUrl":"10.1111/gwat.70025","url":null,"abstract":"<p>Adjoint sensitivity analysis provides an efficient alternative to direct methods when evaluating the influence of many uncertain parameters on a limited number of performance measures in hydrologic and hydrogeologic models. However, most adjoint implementations are “intrusive”, requiring extensive modifications of the forward simulation code. This creates significant development and maintenance burdens that limit broad adoption. To address these needs, we present MF6-ADJ, a “non-intrusive” adjoint sensitivity capability for the MODFLOW 6 groundwater flow process that leverages the MODFLOW Application Programming Interface (API) to interact with the forward groundwater flow solution without altering its core code. MF6-ADJ supports both confined and unconfined flow conditions, structured and unstructured grids, and is compatible with both the Standard and Newton–Raphson solution schemes. It computes sensitivities of a wide range of general performance measures, including hydraulic heads, boundary fluxes, and weighted residuals, with respect to key model parameters such as hydraulic conductivity, storage coefficient, injection/extraction rate, recharge rate, boundary head, and boundary conductance. Sensitivities are computed at each node, enabling fine-grained diagnostic and calibration analysis. Validation against analytical solutions and the finite-difference perturbation method confirms excellent agreement, while demonstrating speedups ranging from hundreds to tens of thousands of times depending on grid discretization, since the adjoint state method computes sensitivities efficiently at the grid-block level. This non-intrusive design makes MF6-ADJ highly accessible and maintainable, offering efficient and scalable sensitivity analysis in complex groundwater modeling workflows.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 6","pages":"874-888"},"PeriodicalIF":2.0,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ngwa.onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.70025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145139800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}