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Ground Water

Scott K Hansen, Velimir V Vesselinov
In modeling solute transport with mobile-immobile mass transfer (MIMT), it is common to use an advection-dispersion equation (ADE) with a retardation factor, or retarded ADE. This is commonly referred to as making the local equilibrium assumption (LEA). Assuming local equilibrium, Eulerian textbook treatments derive the retarded ADE, ostensibly exactly. However, other authors have presented rigorous mathematical derivations of the dispersive effect of MIMT, applicable even in the case of arbitrarily fast mass transfer...
July 19, 2017: Ground Water
Xin Peng, Hongbin Zhan
Measuring a disconnected streambed seepage flux using a seepage meter can give important streambed information and help understanding groundwater-surface water interaction. In this study, we provide a correction for calculating the seepage flux rate with the consideration of air compressibility inside the manometer of the Bouwer and Rice seepage meter. We notice that the effect of air compressibility in the manometer is considerably larger when more air is included in the manometer. We find that the relative error from neglecting air compressibility can be constrained within 5% if the manometer of the Bouwer and Rice seepage meter is shorter than 0...
July 17, 2017: Ground Water
Luk J M Peeters
No abstract text is available yet for this article.
July 17, 2017: Ground Water
Anneli Guthke
No abstract text is available yet for this article.
July 17, 2017: Ground Water
Ombretta Paladino, Arianna Moranda, Marco Massabò, Gary A Robbins
Despite the availability of numerical models, interest in analytical solutions of multidimensional advection-dispersion systems remains high. Such models are commonly used for performing Tier I risk analysis and are embedded in many regulatory frameworks dealing with groundwater contamination. In this work, we develop a closed-form solution of the three-dimensional advection-dispersion equation with exponential source decay, first-order reaction, and retardation, and present an approach based on some ease of use diagrams to compare it with the integral open form solution and with earlier versions of the closed-form solution...
July 17, 2017: Ground Water
Andrew T Leaf
No abstract text is available yet for this article.
July 17, 2017: Ground Water
Philip Womble
No abstract text is available yet for this article.
July 17, 2017: Ground Water
Samuel V Panno, Zohreh Askari, Walton R Kelly, Thomas M Parris, Keith C Hackley
The conservative nature of chloride (Cl(-) ) in groundwater and the abundance of geochemical data from various sources (both published and unpublished) provided a means of developing, for the first time, a representation of the hydrogeology of the Illinois Basin on a basin-wide scale. The creation of Cl(-) isocons superimposed on plan view maps of selected formations and on cross sections across the Illinois Basin yielded a conceptual model on a basin-wide scale of recharge into, groundwater flow within and through the Illinois Basin...
July 17, 2017: Ground Water
Gordon J MacMillan
No abstract text is available yet for this article.
July 11, 2017: Ground Water
Ramon C Naranjo
No abstract text is available yet for this article.
July 11, 2017: Ground Water
Rhiannon M Garrard, Yong Zhang, Song Wei, HongGuang Sun, Jiazhong Qian
Time nonlocal transport models such as the time fractional advection-dispersion equation (t-fADE) were proposed to capture well-documented non-Fickian dynamics for conservative solutes transport in heterogeneous media, with the underlying assumption that the time nonlocality (which means that the current concentration change is affected by previous concentration load) embedded in the physical models can release the effective dispersion coefficient from scale dependency. This assumption, however, has never been systematically examined using real data...
July 10, 2017: Ground Water
Bhavna Arora, James A Davis, Nicolas F Spycher, Wenming Dong, Haruko M Wainwright
A non-electrostatic generalized composite surface complexation model (SCM) was developed for U(VI) sorption on contaminated F-Area sediments from the U.S. Department of Energy Savannah River Site, South Carolina. The objective of this study was to test if a simpler, semi-empirical, non-electrostatic U(VI) sorption model (NEM) could achieve the same predictive performance as a SCM with electrostatic correction terms in describing U(VI) plume evolution and long-term mobility. One-dimensional reactive transport simulations considering key hydrodynamic processes, Al and Fe minerals, as well as H(+) and U surface complexation, with and without electrostatic correction terms, were conducted...
July 6, 2017: Ground Water
Thomas Hermans
No abstract text is available yet for this article.
July 3, 2017: Ground Water
Lucy Marshall
No abstract text is available yet for this article.
July 3, 2017: Ground Water
Jeremy T White
No abstract text is available yet for this article.
July 3, 2017: Ground Water
Guillaume Pirot
No abstract text is available yet for this article.
July 3, 2017: Ground Water
Kristijan Posavec, Marco Giacopetti, Marco Materazzi, Steffen Birk
A new method was developed and implemented into an Excel Visual Basic for Applications (VBAs) algorithm utilizing trigonometry laws in an innovative way to overlap recession segments of time series and create master recession curves (MRCs). Based on a trigonometry approach, the algorithm horizontally translates succeeding recession segments of time series, placing their vertex, that is, the highest recorded value of each recession segment, directly onto the appropriate connection line defined by measurement points of a preceding recession segment...
June 26, 2017: Ground Water
Quanghee Yi, Mark Stewart
The effects of surface water flow system changes caused by constructing water-conservation areas and canals in southeast Florida on groundwater quality under the Atlantic Coastal Ridge was investigated with numerical modeling. Water quality data were used to delineate a zone of groundwater with low total dissolved solids (TDS) within the Biscayne aquifer under the ridge. The delineated zone has the following characteristics. Its location generally coincides with an area where the Biscayne aquifer has high transmissivities, corresponds to a high recharge area of the ridge, and underlies a part of the groundwater mound formed under the ridge prior to completion of the canals...
June 20, 2017: Ground Water
Roger Pacheco Castro, Julia Pacheco Ávila, Ming Ye, Armando Cabrera Sansores
This study develops an approach based on hierarchical cluster analysis for investigating the spatial and temporal variation of water quality governing processes. The water quality data used in this study were collected in the karst aquifer of Yucatan, Mexico, the only source of drinking water for a population of nearly two million people. Hierarchical cluster analysis was applied to the quality data of all the sampling periods lumped together. This was motivated by the observation that, if water quality does not vary significantly in time, two samples from the same sampling site will belong to the same cluster...
June 15, 2017: Ground Water
Giulia de Pasquale
No abstract text is available yet for this article.
June 13, 2017: Ground Water
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