Ground water最新文献

{"title":"Interpreting Step-Drawdown Pumping Test Undergoing Confined-Unconfined Conversion with Well Loss.","authors":"Lu Zhang, Hua Zhao, Ling Wang, Jianmei Liu, Qi Zhu, Na Li, Zhang Wen, Yizhao Wang, Dian Wang","doi":"10.1111/gwat.13450","DOIUrl":"https://doi.org/10.1111/gwat.13450","url":null,"abstract":"<p><p>The step-drawdown pumping test often experiences a transition from confined to unconfined conditions due to the continuously increasing pumping rate. However, the current well hydraulics model has not accurately interpreted this phenomenon. In this study, we developed an analytical solution to address the confined-unconfined conversion in step-drawdown pumping tests based on Girinskii's potential and superposition theory. Additionally, a field step-drawdown pumping test featuring confined-unconfined conversion was conducted to apply the proposed analytical solution. The particle swarm optimization algorithm was employed to simultaneously estimate multiple parameters. The results demonstrate that the newly proposed solution provides a better fit to the observed drawdown in the pumping well compared to previous models. The hydrogeological parameters (K, S), well loss coefficient (B), and critical time for confined-unconfined conversion (t_c) were estimated to be K = 7.15 m/d, S = 6.65 × 10^-5, B = 7.48 × 10^-6, and t_c = 1152 min, respectively. Neglecting the confined-unconfined conversion in step-drawdown pumping tests leads to underestimation of drawdown inside the pumping well due to an overestimation of the aquifer thickness. After the conversion from confined to unconfined conditions, the estimated well loss coefficient decreased by 88% compared to its pre-conversion value. This highlights the necessity of adjusting the well loss coefficient in the step-drawdown pumping test model to account for confined-unconfined conversion. In summary, this study introduces a new method for interpreting parameters in step-drawdown pumping tests and provides field validation for its effectiveness.</p>","PeriodicalId":94022,"journal":{"name":"Ground water","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142570799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conceptualizing Controlling Factors for PFAS Salting Out in Groundwater Discharge Zones Along Sandy Beaches.","authors":"Hiroko M Hort, Clare E Robinson, Audrey H Sawyer, Yue Li, Rebecca Cardoso, Sophia A Lee, Douglas Roff, David T Adamson, Charles J Newell","doi":"10.1111/gwat.13428","DOIUrl":"10.1111/gwat.13428","url":null,"abstract":"<p><p>Understanding fate and transport processes for per- and poly-fluoroalkyl substances (PFAS) is critical for managing impacted sites. \"PFAS Salting Out\" in groundwater, defined herein, is an understudied process where PFAS in fresh groundwater mixes with saline groundwater near marine shorelines, which increases sorption of PFAS to aquifer solids. While sorption reduces PFAS mass discharge to marine surface water, the fraction that sorbs to beach sediments may be mobilized under future salinity changes. The objective of this study was to conceptually explore the potential for PFAS Salting Out in sandy beach environments and to perform a preliminary broad-scale characterization of sandy shoreline areas in the continental U.S. While no site-specific PFAS data were collected, our conceptual approach involved developing a multivariate regression model that assessed how tidal amplitude and freshwater submarine groundwater discharge affect the mixing of fresh and saline groundwater in sandy coastal aquifers. We then applied this model to 143 U.S. shoreline areas with sandy beaches (21% of total beaches in the USA), indirectly mapping potential salinity increases in shallow freshwater PFAS plumes as low (<10 ppt), medium (10-20 ppt), or high (>20 ppt) along groundwater flow paths before reaching the ocean. Higher potential salinity increases were observed in West Coast bays and the North Atlantic coastline, due to the combination of moderate to large tides and large fresh groundwater discharge rates, while lower increases occurred along the Gulf of Mexico and the southern Florida Atlantic coast. The salinity increases were used to estimate potential perfluorooctane sulfonic acid (PFOS) sorption in groundwater due to salting out processes. Low-category shorelines may see a 1- to 2.5-fold increase in sorption of PFOS, medium-category a 2.0- to 6.4-fold increase, and high-category a 3.8- to 25-fold increase in PFOS sorption. The analysis presented provides a first critical step in developing a large-scale approach to classify the PFAS Salting Out potential along shorelines and the limitations of the approach adopted highlights important areas for further research.</p>","PeriodicalId":94022,"journal":{"name":"Ground water","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141473857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal Groundwater Level Dynamics in Unconfined Aquifers across the United States.","authors":"Mason O Stahl, Tyler Mar, Yusuf Jameel","doi":"10.1111/gwat.13422","DOIUrl":"10.1111/gwat.13422","url":null,"abstract":"<p><p>Groundwater hydrographs contain a rich set of information on the dynamics of aquifer systems and the processes and properties that influence them. While the importance of seasonal cycles in hydrologic and environmental state variables is widely recognized there has yet to be a comprehensive analysis of the seasonal dynamics of groundwater across the United States. Here we use time series of groundwater level measurements from 997 wells from the National Groundwater Monitoring Network to identify and describe groundwater seasonal cycles in unconfined aquifers across the United States. We use functional data analysis to obtain a functional form fit for each site and apply an unsupervised clustering algorithm to identify a set of five distinct seasonal cycles regimes. Each seasonal cycle regime has a distinctive shape and distinct timing of its annual minimum and maximum water level. There are clear spatial patterns in the occurrence of each seasonal cycle regime, with the relative occurrence of each regime strongly influenced by the geologic setting (aquifer system), climate, and topography. Our findings provide a comprehensive characterization of groundwater seasonal cycles across much of the United States and present both a methodology and results useful for assessing and understanding unconfined groundwater systems.</p>","PeriodicalId":94022,"journal":{"name":"Ground water","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141297614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of an Impulse-Response Emulator for Groundwater Contaminant Transport Modeling.","authors":"Brent P Heerspink, Michael N Fienen, Howard W Reeves","doi":"10.1111/gwat.13405","DOIUrl":"10.1111/gwat.13405","url":null,"abstract":"<p><p>There is a significant need to develop decision support tools capable of delivering accurate representations of environmental conditions, such as ground and surface water solute concentrations, in a timely and computationally efficient manner. Such tools can be leveraged to assess a large number of potential management strategies for mitigating non-point source pollutants. Here, we assess the effectiveness of the impulse-response emulation approach to approximate process-based groundwater model estimates of solute transport from MODFLOW and MT3D over a wide range of model inputs and parameters, with the goal of assessing where in parameter space the assumptions underlying this emulation approach are valid. The impulse-response emulator was developed using the sensitivity analysis utilities in the PEST++ software suite and is capable of approximating MODFLOW/MT3D estimates of solute transport over a large portion of the parameter space tested, except in cases where the Courant number is above 0.5. Across all runs tested, the highest percent errors were at the plume fronts. These results suggest that the impulse-response approach may be suitable for emulation of solute transport models for a wide range of cases, except when high-resolution outputs are needed, or when very low concentrations at plume edges are of particular interest.</p>","PeriodicalId":94022,"journal":{"name":"Ground water","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140308361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Remembering the Big Picture.","authors":"Kenneth R Bradbury","doi":"10.1111/gwat.13451","DOIUrl":"10.1111/gwat.13451","url":null,"abstract":"","PeriodicalId":94022,"journal":{"name":"Ground water","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142515291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","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, Michael C Sukop, Grace Oldfield, Angela Montoya, Virginia Walsh, Jayantha Obeysekera, Samantha Barquin, Elizabeth Kelly, Katherine Hagemann, Aliza Karim, Oscar F Guzman","doi":"10.1111/gwat.13435","DOIUrl":"10.1111/gwat.13435","url":null,"abstract":"<p><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":94022,"journal":{"name":"Ground water","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141903947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Study of Non-Darcian Flow Characteristics in Low-Permeability Coal Pillar Dams.","authors":"Xu Li, Peng Zhu, Konghui Zuo, Zhang Wen, Qi Zhu, Qiang Guo, Hamza Jakada","doi":"10.1111/gwat.13401","DOIUrl":"10.1111/gwat.13401","url":null,"abstract":"<p><p>The safe operation of underground reservoirs and environmental protection heavily rely on the water flow through coal pillar dams in coal mines. Meanwhile, research on the flow characteristics in coal pillar dams has been limited due to their low hydraulic conductivity. To address this gap, this study assembled a novel seepage experimental device and conducted a series of carefully designed seepage experiments to examine the characteristics of low-permeability in coal pillar dams. The experiments aim to explore the relationship between water flux and hydraulic gradient, considering varying core lengths and immersion times. Flow parameters were determined by fitting observed flux-gradient curves with predictions from both Darcy and non-Darcian laws. Several significant results were obtained. First, a noticeable non-linear relationship between water flux and hydraulic gradient was observed, particularly evident at low flow velocities. Second, the non-Darcy laws effectively interpreted the experimental data, with threshold pressure gradients ranging 13.60 to 58.64 for different core lengths. Third, the study established that water immersion significantly affects the flow characteristics of coal pillar dams, resulting in an increased hydraulic conductivity and flow velocity. These findings carry significant implications for the design of coal pillar dams within underground coal mine reservoirs, providing insights for constructing more stable structures and ensuring environmental protection.</p>","PeriodicalId":94022,"journal":{"name":"Ground water","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140095413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Imputation Method for Simulating 3D Well Screen Locations from Limited Regional Well Log Data.","authors":"Georgios Kourakos, Rich Pauloo, Thomas Harter","doi":"10.1111/gwat.13424","DOIUrl":"10.1111/gwat.13424","url":null,"abstract":"<p><p>In groundwater modeling studies, accurate spatial and intensity identification of water sources and sinks is of critical importance. Precise construction data about wells (water sinks) are particularly difficult to obtain. The collection of well log data is expensive and laborious, and government records of historic well log data are often imprecise and incomplete with respect to the precise location or pumping rate. In many groundwater modeling studies, such as groundwater quality assessments, a precise representation of the horizontal and vertical distribution of well screens is required to accurately estimate contaminant breakthrough curves. The number of wells under consideration may be very large, for example, in the assessment of nonpoint source pollution. In this paper, we propose an imputation framework that allows for proper reconstruction of missing well data. Our approach exploits available information and tolerates data gaps and imprecisions. We demonstrate the value of this method for a subregion of the Central Valley aquifer (California, USA). We show that our framework imputes missing values that preserve statistical properties of available data and that remain consistent with the known spatial distribution of well screens and pumping rates in the three-dimensional aquifer system.</p>","PeriodicalId":94022,"journal":{"name":"Ground water","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141461357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Jupyter Notebooks for Parameter Estimation, Uncertainty Analysis, and Optimization with PEST+.","authors":"Chanse Ford, Wonsook Ha, Katherine Markovich, Johanna Zwinger","doi":"10.1111/gwat.13447","DOIUrl":"10.1111/gwat.13447","url":null,"abstract":"","PeriodicalId":94022,"journal":{"name":"Ground water","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142585410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Hydraulic Evolution of Groundwater-Fed Pit Lakes After Mine Closure.","authors":"Birte Moser, Peter G Cook, Anthony D Miller, Shawan Dogramaci, Ilka Wallis","doi":"10.1111/gwat.13419","DOIUrl":"10.1111/gwat.13419","url":null,"abstract":"<p><p>Open pit mining frequently requires regional water tables to be lowered to access ore deposits. When mines close, dewatering ceases allowing the water table to recover. In arid and semi-arid mining regions, the developing pit lakes are predominantly fed by groundwater during this recovery phase and pit lakes develop first into \"terminal sinks\" for the surrounding groundwater system. With time, the re-establishment of regional hydraulic gradients can cause pit lakes to develop into throughflow systems, in which pit lake water outflows into adjacent aquifers. In this study, we use numerical groundwater modeling to aid process understanding of how regional hydraulic gradients, aquifer properties, net evaporation rates, and pit geometry determine the hydraulic evolution of groundwater-fed pit lakes. We find that before the recovery of the regional water table to its new equilibrium, pit lakes frequently transition to throughflow systems. Throughflow from pit lakes to downstream aquifers can develop within two decades following cessation of dewatering even under low hydraulic gradients (e.g., 5 × 10^-4) or high net evaporation rates (e.g., 2.5 m/year). Pit lakes remain terminal sinks only under suitable combinations of high evaporation rates, low hydraulic gradients, and low hydraulic conductivities. In addition, we develop an approximate analytical solution for a rapid assessment of the hydraulic status of pit lakes under steady-state conditions. Understanding whether pit lakes remain terminal sinks or transition into throughflow systems largely determines the long-term water quality of pit lakes and downstream aquifers. This knowledge is fundamental for mine closure and planning post-mining land use.</p>","PeriodicalId":94022,"journal":{"name":"Ground water","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141201578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}