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Ground Water

Hugo A Loáiciga
Methods for calculating the safe yield are evaluated in this paper using a high-quality and long historical data set of groundwater recharge, discharge, extraction, and precipitation in a karst aquifer. Consideration is given to the role that climatic variability has on the determination of a climatically representative period with which to evaluate the safe yield. The methods employed to estimate the safe yield are consistent with its definition as a long-term average extraction rate that avoids adverse impacts on groundwater...
October 25, 2016: Ground Water
Stewart W Taylor, Hillol Guha
An analytical solution for calculating the contaminant discharge rate in an aquifer following an instantaneous release of reactive contaminant mass to groundwater is used to derive relationships for the time and magnitude of peak concentration in a river receiving the transported material. Relationships are developed for the time of peak concentration relative to the time of travel for the contaminant, and the magnitude of peak concentration relative to the concentration calculated at the time of travel. Both quantities are found to be a function of two dimensionless parameters characterizing advective-dispersive-reactive transport-the Peclet number and the Damkohler number...
October 24, 2016: Ground Water
Thomas B Atherholt, Nicholas A Procopio, Sandra M Goodrow
It is important that indicators of fecal pollution are reliable. Coliform bacteria are a commonly used indicator of fecal pollution. As other investigators have reported elsewhere, we observed a seasonal pattern of coliform bacteria detections in domestic wells in New Jersey. Examination of a statewide database of 10 years of water quality data from 93,447 samples, from 78,207 wells, generated during real estate transactions, revealed that coliform bacteria were detected in a higher proportion of wells during warm weather months...
October 24, 2016: Ground Water
Pradeep Mugunthan, Kevin T Russell, Binglei Gong, Michael J Riley, Arthur Chin, Blair G McDonald, Linda J Eastcott
There is an identified need for fully representing groundwater-surface water transition zone (i.e., the sediment zone that connects groundwater and surface water) processes in modeling fate and transport of contaminants to assist with management of contaminated sediments. Most existing groundwater and surface water fate and transport models are not dynamically linked and do not consider transition zone processes such as bioturbation and deposition and erosion of sediments. An interface module is developed herein to holistically simulate the fate and transport by coupling two commonly used models, Environmental Fluid Dynamics Code (EFDC) and SEAWAT, to simulate surface water and groundwater hydrodynamics, while providing an enhanced representation of the processes in the transition zone...
October 24, 2016: Ground Water
Hossein Rajabpour, Abdorreza Vaezihir
The North Tabriz Fault (NTF) is the predominant regional-scale tectonic structure in the northwest of Iran. In the east side of the city of Tabriz, a portion of the fault trend has been completely concealed by recent sediments and urbanization. In this paper, some hydrogeological methods are used to locate the concealed sector. As is clear from the pumping tests results, despite the fact that the northern observation wells were closer to the pumping wells than the southern ones, they have not been affected by pumping...
October 17, 2016: Ground Water
Abdullah H A Dehwah, Samir Al-Mashharawi, Kim Choon Ng, Thomas M Missimer
An investigation of a sea water reverse osmosis desalination facility located in western Saudi Arabia has shown that aquifer treatment of the raw sea water provides a high degree of removal of natural organic matter (NOM) that causes membrane biofouling. The aquifer is a carbonate system that has a good hydraulic connection to the sea and 14 wells are used to induce sea water movement 400 to 450 m from the sea to the wells. During aquifer transport virtually all of the algae, over 90% of the bacteria, over 90% of the biopolymer fraction of NOM, and high percentages of the humic substance, building blocks, and some of the low molecular weight fractions of NOM are removed...
October 17, 2016: Ground Water
Carl Hauge
No abstract text is available yet for this article.
October 12, 2016: Ground Water
Rebecca Nelson, Debra Perrone
No abstract text is available yet for this article.
October 12, 2016: Ground Water
William M Alley, Lisa Beutler, Michael E Campana, Sharon B Megdal, John C Tracy
No abstract text is available yet for this article.
October 12, 2016: Ground Water
Avihu Burg, Ittai Gavrieli, Joseph Guttman
An ancient, brackish, anoxic, and relatively hot water body exists within the Yarqon-Tanninim Aquifer in southern Israel. A hydrogeological-geochemical conceptual model is presented, whereby the low water quality is the outcome of three conditions that are met simultaneously: (1) Presence of an organic-rich unit with low permeability that overlies and confines the aquifer; the confining unit contains perched horizons with relatively saline water. (2) Local phreatic/roofed conditions within the aquifer that enable seepage of the organic-rich brackish water from above...
October 11, 2016: Ground Water
Omkar Aphale, David J Tonjes
We demonstrate the application of the Area Metric developed by Ferson et al. (2008) for multimodel validity assessment. The Area Metric quantified the degree of models' replicative validity: the degree of agreement between the observed data and the corresponding simulated outputs represented as their empirical cumulative distribution functions (ECDFs). This approach was used to rank multiple representations of a case study groundwater flow model of a landfill by their Area Metric scores. A multimodel approach allows to account for uncertainties that may either be epistemic (from lack of knowledge) or aleatory (from variability inherent in the system)...
October 5, 2016: Ground Water
Dylan J Irvine, Martin A Briggs, Laura K Lautz, Ryan P Gordon, Jeffrey M McKenzie, Ian Cartwright
Heat is a powerful tracer to quantify fluid exchange between surface water and groundwater. Temperature time series can be used to estimate pore water fluid flux, and techniques can be employed to extend these estimates to produce detailed plan-view flux maps. Key advantages of heat tracing include cost-effective sensors and ease of data collection and interpretation, without the need for expensive and time-consuming laboratory analyses or induced tracers. While the collection of temperature data in saturated sediments is relatively straightforward, several factors influence the reliability of flux estimates that are based on time series analysis (diurnal signals) of recorded temperatures...
October 3, 2016: Ground Water
Patrick Höhener, Zhi M Li, Maxime Julien, Pierrick Nun, Richard J Robins, Gérald S Remaud
BIOSCREEN is a well-known simple tool for evaluating the transport of dissolved contaminants in groundwater, ideal for rapid screening and teaching. This work extends the BIOSCREEN model for the calculation of stable isotope ratios in contaminants. A three-dimensional exact solution of the reactive transport from a patch source, accounting for fractionation by first-order decay and/or sorption, is used. The results match those from a previously published isotope model but are much simpler to obtain. Two different isotopes may be computed, and dual isotope plots can be viewed...
October 3, 2016: Ground Water
Shrikant Daji Limaye
No abstract text is available yet for this article.
September 30, 2016: Ground Water
Joshua W Brownlow, Joe C Yelderman, Scott C James
Interaction between hydraulically generated fractures and existing wells (frac hits) could represent a potential risk to groundwater. In particular, frac hits on abandoned oil and gas wells could lead to upward leakage into overlying aquifers, provided migration pathways are present along the abandoned well. However, potential risk to groundwater is relatively unknown because few studies have investigated the probability of frac hits on abandoned wells. In this study, actual numbers of frac hits were not determined...
September 27, 2016: Ground Water
Vicki Kretsinger Grabert, Dawn Samara Kaback
No abstract text is available yet for this article.
September 26, 2016: Ground Water
Bin Chen, Xiangyun Hu, Jianhui Li, Yajun Liu
Surface nuclear magnetic resonance (SNMR) is a relatively new geophysical method for non-invasive groundwater exploration and aquifer characterization. Conventional SNMR surveys based on one-dimensional (1-D) inversion of amplitude data recorded only using coincident loops provide limited or distorted groundwater distribution information, especially in regions with strong lateral heterogeneity and complicated hydrological environments. The simplistic approach limits the applicability and efficiency of SNMR, which was therefore made more effective in this study using a sophisticated signal response formulation...
September 19, 2016: Ground Water
P Fischer, A Jardani, A Soueid Ahmed, M Abbas, X Wang, H Jourde, N Lecoq
Large-scale inversion methods have been recently developed and permitted now to considerably reduce the computation time and memory needed for inversions of models with a large amount of parameters and data. In this work, we have applied a deterministic geostatistical inversion algorithm to a hydraulic tomography investigation conducted in an experimental field site situated within an alluvial aquifer in Southern France. This application aims to achieve a 2-D large-scale modeling of the spatial transmissivity distribution of the site...
September 19, 2016: Ground Water
A E Brookfield, G L Macpherson, M D Covington
Climate predictions indicate that precipitation patterns will change and average air temperatures will increase across much of the planet. These changes will alter surface water and groundwater temperatures which can significantly affect the local and regional environment. Here, we examine the role of precipitation timing in changes to groundwater temperature in carbonate-karst aquifers using measured groundwater level and temperature data from the Konza Prairie Long-Term Ecological Research Site, Kansas. We demonstrate that shifts to increased cool-season precipitation may mitigate the increases in groundwater temperature produced by increases in average annual air temperature...
September 19, 2016: Ground Water
Mark R Williams, Anthony R Buda, Kamini Singha, Gordon J Folmar, Herschel A Elliott, John P Schmidt
Delineating hydrologic and pedogenic factors influencing groundwater flow in riparian zones is central in understanding pathways of water and nutrient transport. In this study, we combined two-dimensional time-lapse electrical resistivity imaging (ERI) (depth of investigation approximately 2 m) with hydrometric monitoring to examine hydrological processes in the riparian area of FD-36, a small (0.4 km(2) ) agricultural headwater basin in the Valley and Ridge region of east-central Pennsylvania. We selected two contrasting study sites, including a seep with groundwater discharge and an adjacent area lacking such seepage...
September 12, 2016: Ground Water
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