GroundwaterPub Date : 2024-10-27DOI: 10.1111/gwat.13451
Kenneth R. Bradbury
{"title":"Remembering the Big Picture","authors":"Kenneth R. Bradbury","doi":"10.1111/gwat.13451","DOIUrl":"10.1111/gwat.13451","url":null,"abstract":"<p>As a practicing hydrogeologist, I have assisted many people and communities who have problem wells or water shortages. But when I recently experienced my own water shortage, I realized how much we in developed countries depend on and take for granted that the water will just be there, and will be fit to drink, when we turn on the tap. In late May of this year, thunderstorms and a few tornados rumbled across the midwestern United States, including our home in southern Wisconsin. My wife and I live in a rural area and are accustomed to thunderstorms in the spring. We are also used to occasional electric power outages, which happen three or four times a year and usually last from 15 min to an hour. So, we weren't especially surprised or worried when our lights went out during the storm. Suddenly, our home was silent except for the rain on the windows—no TV, no radio, no internet, no refrigerator, no lights—and no water, because we depend on our domestic well and pump. Our system usually holds enough water and pressure for a couple of toilet flushes and face washes, but that's it. When the blackout lasts 1 to 2 h, no problem. But when it lasts for 24, then 48, then 60 h, as it did this time, we realize how much we take our well, and our water, for granted. We had no water stockpiled. Fortunately, I was able to drive to a convenience store and purchase a few gallons of “pure spring water” to get us through the requisite drinking, face washing, and tooth brushing, but flushing the toilets was a more complicated matter. Our older home has standard toilets, which require about 7 gal per flush (unlike the newer low-flow toilets). I found myself lugging buckets of water up a hill from a nearby stream (and 7 gal weighs around 58 pounds) for flushing toilets and watering our neighbors' horses.</p><p>Obviously, my power outage was just a minor inconvenience compared to the problems of billions of people faced with real disasters and perpetual water shortages. Based on research by Mekonnen and Hoekstra (<span>2016</span>), UNICEF reports that “…four billion people—almost two thirds of the world's population—experience severe water scarcity for at least one month each year, and over two billion people live in countries where water supply is inadequate (https://www.unicef.org/wash/water-scarcity).” This experience made me contemplate the scope of groundwater science and wonder if we are emphasizing the right things in our work and ignoring the big picture while we focus on the small stuff.</p><p><i>Groundwater's</i> publisher, Wiley, lists the top four issue categories addressed by papers in the journal during the past year as, (1) groundwater flow models; (2) groundwater/aquifer recharge; (3) flow/solute transport simulation; and (4) groundwater solute composition and concentrations. These are all important and interesting topics but may not directly address one of the fundamental issues of our time—global water supply and sustainability, the topic of a rece","PeriodicalId":12866,"journal":{"name":"Groundwater","volume":"62 6","pages":"820-821"},"PeriodicalIF":2.0,"publicationDate":"2024-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.13451","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142515291","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}
GroundwaterPub Date : 2024-08-07DOI: 10.1111/gwat.13435
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
{"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>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 km<sup>2</sup> 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 m<sup>3</sup>/d and Biscayne Bay (5696 m<sup>3</sup>/d), and well fields (14,066 m<sup>3</sup>/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}
GroundwaterPub Date : 2024-07-04DOI: 10.1111/gwat.13425
Bwalya Malama, Ying-Fan Lin, Kristopher L. Kuhlman
{"title":"Semi-Analytical Modeling of Transient Stream Drawdown and Depletion in Response to Aquifer Pumping","authors":"Bwalya Malama, Ying-Fan Lin, 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}
GroundwaterPub Date : 2024-06-28DOI: 10.1111/gwat.13428
Hiroko M. Hort, Clare E. Robinson, Audrey H. Sawyer, Yue Li, Rebecca Cardoso, Sophia A. Lee, Douglas Roff, David T. Adamson, Charles J. Newell
{"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>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":12866,"journal":{"name":"Groundwater","volume":"62 6","pages":"860-875"},"PeriodicalIF":2.0,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141473857","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}
GroundwaterPub Date : 2024-06-27DOI: 10.1111/gwat.13424
Georgios Kourakos, Rich Pauloo, Thomas Harter
{"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>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":12866,"journal":{"name":"Groundwater","volume":"62 6","pages":"920-933"},"PeriodicalIF":2.0,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.13424","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141461357","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}
GroundwaterPub Date : 2024-06-10DOI: 10.1111/gwat.13422
Mason O. Stahl, Tyler Mar, Yusuf Jameel
{"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>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":12866,"journal":{"name":"Groundwater","volume":"62 6","pages":"876-888"},"PeriodicalIF":2.0,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141297614","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}