Groundwater最新文献

{"title":"MS Students Are the Missing Link in the Future of Hydrogeology – And How You Can Help!","authors":"Ty Ferre","doi":"10.1111/gwat.13439","DOIUrl":"10.1111/gwat.13439","url":null,"abstract":"<p>As readers of <i>Groundwater</i>, you have all faced a quizzical look when you told someone that you are a hydrogeologist. You have discovered that simply repeating the word—although, after all, it describes itself—is rarely sufficient. So, you have developed your own short explanation for what a hydrogeologist does and why our work is critical to society (one of my favorite is, “You know that water you drank yesterday? You're welcome.”). If you are in a position to hire an entry-level professional hydrogeologist, you are likely to share something else: a growing concern that there are not enough graduates to fill current demand, let alone future needs for our profession.</p><p>In summary, the future of hydrogeology is bright, but we are not producing enough MS-level trained students even to meet the current demand. In addition, universities are moving away from their role as the principal source of master's graduates and are unlikely to fill the future needs of industry or academia.</p><p>The good news is that there are several efforts in progress to address this problem. Some programs (e.g., the University of Neuchatel) have strong enrollment and continue to produce graduates. Other programs are coming together to offer multi-university degrees (e.g., the European ERASMUS+ cooperation project iNUX). In addition, there are efforts to redesign the university-based MS to deliver accessible in-person (e.g., the University of Arizona) or hybrid in-person/online programs (e.g., the University of Kansas and the University of Waterloo). There are also extra-university programs that focus on advanced topics (e.g., the Italian SYMPL School of Hydrogeologic Modeling). Finally, there are efforts to make videos and textbooks available for free to support educational programs (e.g., the micro-video project, the Groundwater Modeling for Decision Support Initiative, and the Groundwater Project).</p><p>We need all of these efforts to succeed if we hope to produce the workforce that will be needed in the future. However, there is a crucial first step that we need to complete as a community to ensure that future students are receiving the training that they need to enter the profession.</p><p>This is where we need your help as groundwater professionals.</p><p>Thank you for being part of the <i>Groundwater</i> community and I hope to work with you to advance our profession into the future!</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"62 5","pages":"662-663"},"PeriodicalIF":2.0,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.13439","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141989742","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":"The Effective Vertical Anisotropy of Layered Aquifers","authors":"Mark Bakker,&nbsp;Bram Bot","doi":"10.1111/gwat.13432","DOIUrl":"10.1111/gwat.13432","url":null,"abstract":"<p>Many sedimentary aquifers consist of small layers of coarser and finer material. When groundwater flow in these aquifers is modeled, the hydraulic conductivity may be simulated as homogeneous but anisotropic throughout the aquifer. In practice, the anisotropy factor, the ratio of the horizontal divided by the vertical hydraulic conductivity, is often set to 10. Here, numerical experiments are conducted to determine the effective anisotropy of an aquifer consisting of 400 horizontal layers of which the homogeneous and isotropic hydraulic conductivity varies over two orders of magnitude. Groundwater flow is simulated to a partially penetrating canal and a partially penetrating well. Numerical experiments are conducted for 1000 random realizations of the 400 layers, by varying the sequence of the layers, not their conductivity. It is demonstrated that the effective anisotropy of the homogeneous model is a model parameter that depends on the flow field. For example, the effective anisotropy for flow to a partially penetrating canal differs from the effective anisotropy for flow to a partially penetrating well in an aquifer consisting of the exact same 400 layers. The effective anisotropy also depends on the sequence of the layers. The effective anisotropy values of the 1000 realizations range from roughly 5 to 50 for the considered situations. A factor of 10 represents a median value (a reasonable value to start model calibration for the conductivity variations considered here). The median is similar to the equivalent anisotropy, defined as the arithmetic mean of the hydraulic conductivities divided by the harmonic mean.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 1","pages":"68-75"},"PeriodicalIF":2.0,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11697527/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141989743","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":"Utility of an Instantaneous Salt Dilution Method for Measuring Streamflow in Headwater Streams","authors":"Karli M. Rogers,&nbsp;Jennifer B. Fair,&nbsp;Nathaniel P. Hitt,&nbsp;Karmann G. Kessler,&nbsp;Zachary A. Kelly,&nbsp;Martin Briggs","doi":"10.1111/gwat.13437","DOIUrl":"10.1111/gwat.13437","url":null,"abstract":"<p>Streamflow records are biased toward large streams and rivers, yet small headwater streams are often the focus of ecological research in response to climate change. Conventional flow measurement instruments such as acoustic Doppler velocimeters (ADVs) do not perform well during low-flow conditions in small streams, truncating the development of rating curves during critical baseflow conditions dominated by groundwater inflow. We revisited an instantaneous solute tracer injection method as an alternative to ADVs based on paired measurements to compare their precision, efficiency, and feasibility within headwater streams across a range of flow conditions. We show that the precision of discharge measurements using salt dilution by slug injection and ADV methods were comparable overall, but salt dilution was more precise during the lowest flows and required less time to implement. Often, headwater streams were at or below the depth threshold where ADV measurements could even be attempted and transects were complicated by coarse bed material and cobbles. We discuss the methodological benefits and limitations of salt dilution by slug injection and conclude that the method could facilitate a proliferation of streamflow observation across headwater stream networks that are highly undersampled compared to larger streams.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 1","pages":"80-92"},"PeriodicalIF":2.0,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.13437","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141972481","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":"Society News","authors":"","doi":"10.1111/gwat.13438","DOIUrl":"https://doi.org/10.1111/gwat.13438","url":null,"abstract":"","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"62 5","pages":"664"},"PeriodicalIF":2.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142123283","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":"Septic Return Flow Pathlines, Endpoints, and Flows Based on the Urban Miami-Dade Groundwater Model","authors":"Miguel E. Valencia,&nbsp;Michael C. Sukop,&nbsp;Grace Oldfield,&nbsp;Angela Montoya,&nbsp;Virginia Walsh,&nbsp;Jayantha Obeysekera,&nbsp;Samantha Barquin,&nbsp;Elizabeth Kelly,&nbsp;Katherine Hagemann,&nbsp;Aliza Karim,&nbsp;Oscar F. Guzman","doi":"10.1111/gwat.13435","DOIUrl":"10.1111/gwat.13435","url":null,"abstract":"<p>Miami-Dade County (MDC) has over 112,000 septic systems, some of which are at risk of compromise due to water table rise associated with sea level rise. MDC is surrounded by protected water bodies, including Biscayne Bay, with environmentally sensitive ecosystems and is underlain by highly transmissive karstic limestone. The main objective of the study is to provide first estimates of the locations and magnitudes of septic return flows to discharge endpoints. This is accomplished by leveraging MDC's county-scale surface-groundwater model using pathline analysis to estimate the transport and discharge fate of septic system flows under the complex time history of groundwater flow response to pumping, canal management, storms, and other environmental factors. The model covers an area of 4772 km² in Southeast Florida. Outputs from the model were used to create a 30-year (2010 to 2040) simulation of the spatial–temporal pathlines from septic input locations to their termination points, allowing us to map flow paths and the spatial distribution of the septic flow discharge endpoints under the simulated conditions. Most septic return flows were discharged to surface water, primarily canals 52,830 m³/d and Biscayne Bay (5696 m³/d), and well fields (14,066 m³/d). Results allow us to identify “hotspots” to guide water quality sampling efforts and to provide recommendations for septic-to-sewer conversion areas that should provide most benefit by reducing nutrient loading to water bodies.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"62 6","pages":"957-971"},"PeriodicalIF":2.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.13435","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141903947","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":"Numerical Modeling of Recovery of Moisture from the Unsaturated Zone: A Feasibility Study","authors":"Amitabha Mukhopadhyay,&nbsp;Adnan Akber,&nbsp;Harish Bhandary","doi":"10.1111/gwat.13436","DOIUrl":"10.1111/gwat.13436","url":null,"abstract":"<p>Numerical modeling of the recovery of moisture by injecting warm air in the unsaturated zone in a 100 m × 100 m plot of agricultural land in Kuwait, a country located in an arid environment, was conducted to provide “proof of concept” of the technique. If technically and economically feasible, it will be a potential additional source of water that could be exploited for farming activities and other uses. The COMSOL software was used to develop the model and, based on the results of the scenario runs, the effects of different hydraulic and operational parameters, including that of well spacing, on moisture recovery were assessed. In general, the results suggested that the recovery should increase with the increase in the hydraulic conductivity of the unsaturated zone, the amount of heat input, and the pressure differential between the unsaturated zone and the well head. Within the period examined (0 to 11 days), the recovery decreases with the increase in the soil moisture content, possibly due to the fall in relative permeability to moisture-rich air with the increased water contents in the pore spaces, although the effects may change over a longer period as water contents decrease with moisture recovery. The moisture recovery from the unsaturated zone through the injection of warm air appears to be a feasible proposition from this study that should be demonstrated through a pilot scale experiment in the field.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 1","pages":"116-129"},"PeriodicalIF":2.0,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.13436","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141891366","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":"Enhanced Removal of Brine From Porous Structures by Supercritical CO2","authors":"Iris Beatriz Vega Erramuspe,&nbsp;Osei Asafu-Adjaye,&nbsp;Melissa Rojas-Márquez,&nbsp;Brian Via,&nbsp;Bhima Sastri,&nbsp;Sujit Banerjee","doi":"10.1111/gwat.13434","DOIUrl":"10.1111/gwat.13434","url":null,"abstract":"<p>Supercritical CO₂ (sCO₂) removes water from brine held in pumice stone at levels well above the solubility of water in sCO₂. The higher water removal results from a combination of passive emulsification of water in sCO₂ and viscous fingering of sCO₂ through the saturated pumice. This leads to higher levels of salt deposition than that expected from solubility considerations alone. These deposits could impact the injectivity of sCO₂ as well as its movement in the subsurface. The finding that the water concentration in sCO₂ is not necessarily capped at the solubility limit should influence the parametrization of injection models.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 1","pages":"76-79"},"PeriodicalIF":2.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.13434","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141753571","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":"Parameter ESTimation With the Gauss–Levenberg–Marquardt Algorithm: An Intuitive Guide","authors":"Michael N. Fienen,&nbsp;Jeremy T. White,&nbsp;Mohamed Hayek","doi":"10.1111/gwat.13433","DOIUrl":"10.1111/gwat.13433","url":null,"abstract":"<p>In this paper, we review the derivation of the Gauss–Levenberg–Marquardt (GLM) algorithm and its extension to ensemble parameter estimation. We explore the use of graphical methods to provide insights into how the algorithm works in practice and discuss the implications of both algorithm tuning parameters and objective function construction in performance. Some insights include understanding the control of both parameter trajectory and step size for GLM as a function of tuning parameters. Furthermore, for the iterative Ensemble Smoother (iES), we discuss the importance of noise on observations and show how iES can cope with non-unique outcomes based on objective function construction. These insights are valuable for modelers using PEST, PEST++, or similar parameter estimation tools.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 1","pages":"93-104"},"PeriodicalIF":2.0,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.13433","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141750101","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":"Using Expert Participation to Evaluate the Accuracy of Hand-Drawn Water-Table Maps","authors":"Sarah Kathleen Marshall,&nbsp;Luk J. M. Peeters,&nbsp;Okke Batelaan,&nbsp;Saskia Noorduijn,&nbsp;Tanah Velterop","doi":"10.1111/gwat.13431","DOIUrl":"10.1111/gwat.13431","url":null,"abstract":"<p>Water-table maps are fundamental to hydrogeological studies and a manual, hand-drawn method is still commonly used to produce them. Despite this, the accuracy and variability of such maps have received little attention in international literature. In a unique experiment, 63 groundwater professionals drew water-table equipotential contours based on the same dataset of point measurements and were asked to infer flow directions and predict groundwater elevations at predefined locations. The root mean squared error (RMSE) for the average map calibration data was 10.5 m, which is accuracy comparable to numerical groundwater models. This study confirmed that to produce hand-drawn water-table maps, practitioners seek to not only fit the spatial data, but also to conform to their own cognitive model of hydrogeological concepts and processes. The calibration accuracy increased with experience; from a RMSE of 13.3 m for practitioners with 0–3 years of experience to a RMSE of 9.2 m for those with four or more years. Despite considerable variability in the style of the hand-drawn water-table maps, the maps were consistent in their representation of the dominant regional groundwater flow directions. There was less consensus, however, in predicting the direction of surface water-groundwater interaction for a stream reach. Hand-drawn water-table mapping remains useful and valid, especially as a starting point for hydrogeological conceptualization, yet further work is required to resolve issues around transparency, repeatability, and reproducibility.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"63 1","pages":"52-67"},"PeriodicalIF":2.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11697533/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141636243","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":"Semi-Analytical Modeling of Transient Stream Drawdown and Depletion in Response to Aquifer Pumping","authors":"Bwalya Malama,&nbsp;Ying-Fan Lin,&nbsp;Kristopher L. Kuhlman","doi":"10.1111/gwat.13425","DOIUrl":"10.1111/gwat.13425","url":null,"abstract":"<p>Analytical and semi-analytical models for stream depletion with transient stream stage drawdown induced by groundwater pumping are developed to address a deficiency in existing models, namely, the use of a fixed stream stage condition at the stream–aquifer interface. Field data are presented to demonstrate that stream stage drawdown does indeed occur in response to groundwater pumping near aquifer-connected streams. A model that predicts stream depletion with transient stream drawdown is developed based on stream channel mass conservation and finite stream channel storage. The resulting models are shown to reduce to existing fixed-stage models in the limit as stream channel storage becomes infinitely large, and to the confined aquifer flow with a no-flow boundary at the streambed in the limit as stream storage becomes vanishingly small. The model is applied to field measurements of aquifer and stream drawdown, giving estimates of aquifer hydraulic parameters, streambed conductance, and a measure of stream channel storage. The results of the modeling and data analysis presented herein have implications for sustainable groundwater management.</p>","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"62 6","pages":"904-919"},"PeriodicalIF":2.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141499988","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}