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A simple descriptive-statistical approach is proposed for evaluating the transmissivity of fractured-bedrock under field conditions. Based on standard well logging and identification of structural discontinuities from borehole televiewer, the approach consists of four steps: (1) determination of discontinuity properties, namely the frequency of discontinuities and the ratio of open fractures along the borehole; (2) ranking the three well logs and the discontinuity properties into tertiles (high-to-low); (3) performing statistical analysis ( F-test) for the three well logs to assess the significance of open fractures on the water-transmitting potential and then assigned a weighting factor; and (4) a semi-quantitative indicator, RGVFO, is obtained by multiplying all predictive indexes and weighting factors. It is a multi-criteria evaluation procedure that elucidates the quantitative and qualitative importance of all selected geophysical indexes. A high cross-correlation between transmissivity to RGVFO value is found, which indicates that by a combined consideration of well logging and structural discontinuities, an appropriate estimate of bedrock water-transmitting potential can be derived. [ABSTRACT FROM AUTHOR]

While in catchment and hillslope hydrology a more nuanced approach is now taken to streamflow recession analysis, in the context of major aquifers it is commonly still assumed that the groundwater head recession rate will take exponential form, an idea originally proposed in the 19th Century. However it is shown here that, in early times, the groundwater head recession in a major aquifer should take an almost straight line form with a rate approximately equal to the long-term recharge rate divided by the aquifer storage coefficient. The length of this phase can be estimated from an analytical expression derived in the paper which depends on the aquifer diffusivity, length scale, and the position of the monitoring point. A transitional phase then leads to an exponential phase after some critical time which is independent of the position of the monitoring point. Major aquifers in a state of periodic quasi-steady state are expected to have rates of groundwater flux recession which deviate little from the average rate of groundwater recharge. Where quasi-exponential groundwater declines are observed in nature, their form may be diagnostic of particular types of aquifer properties and/or boundary effects, such as proximity to drainage boundaries, variations in transmissivity with hydraulic head, storage changes due to pumping, nonequilibrium flow at a range of spatial and temporal scales, and variations in specific yield with depth. Recession analysis has applicability to a range of groundwater problems and is powerful way of gaining insight into the hydrologic functioning of an aquifer. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We have developed a drawdown solution for a partially penetrating well under constant flux pumping in a confined aquifer with finite thickness. The predictions of our solution diverge from the predictions of Hantush's solution (), particularly for problems with low ratios of well screen length to aquifer thickness. Furthermore, the predicted drawdown from Hantush's solution () differs from that of Yang et al.'s solution Water Resour Res 42:W0552, () only near the well and at small time values as indicated in Yang et al. Water Resour Res 42:W0552, (). Our solution is based on Green's function with a columnar source (sink) that represents pumping from a finite-radius well. Hantush's solution () and Yang et al.'s solution Water Resour Res 42:W0552, (), however, were derived from Laplace transform techniques for pumping in a well with an infinitesimal and a finite radius, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: Groundwaters of the Winnipeg Formation have been found to have Ba concentrations in excess of drinking groundwater guidelines over an area of several hundred square kilometers. Water samples are at or near barite saturation, however SO4 concentrations are exceedingly low. This inequality suggests that SO4 is being lost from the groundwater, allowing for a buildup of Ba in solution as barite saturation is maintained. The focus of this study is to investigate the relationship between Ba and SO4 and its application to anomalously high Ba concentrations found in the formation. These relationships are investigated through the use of transport modeling in PhreeqC. The model consists of the mixing two end-member waters that are found within the formation, reacting the mixed water with dissolved organic carbon, and transporting the newly mixed and reacted water through the formation. [Copyright &y& Elsevier]

Pumping tests are still the most reliable procedure to obtain hydrogeologic properties of the aquifer, although not always the interpretation procedures are applied properly. This can have an important impact in the magnitudes of these parameters. The new formulations and methodology for determination of hydrogeological properties in non linear flow from pumping tests already differ from those earlier proposed by Pérez Franco D. (1995, 2005) in both methods. The author stands out the importance of the second method in that it does not require two observation wells and, at the same time, it is possible to obtain the equation to find out structural losses or pumping well imperfections, which are of great importance in the knowledge of its efficiency. [ABSTRACT FROM AUTHOR]

Summary: To better understand the spatial distribution of groundwater salinisation in western Victoria, southeast Australia, the interactions between a surficial basalt aquifer and an underlying extensive palaeodrainage (‘deep lead’) system were studied using a multi-disciplinary approach, combining strontium isotope analyses with major ion chemistry and the interpretation of geological and hydrogeological data. The strontium isotopes proved particularly useful in delineating flow paths and hydraulic connections between the two aquifers, which have contrasting 87Sr/86Sr ratios. The freshest basalt groundwaters lie beneath volcanoes and have 87Sr/86Sr signatures close to the whole-rock strontium isotope ratios of the basalts (∼0.7045), indicating the strong influence of basalt weathering. With increasing distance from the eruption points, basalt groundwaters become progressively more saline and the strontium isotope ratios evolve towards the more radiogenic signatures of local rainfall (0.710–0.711), due to the slow addition of infiltration concentrated by evapotranspiration during its passage through the thick, clay-rich soils developed on the basalt lavas. Overall, the influence of rainwater on the strontium isotope signatures of the basalt groundwater is much greater than that of basaltic weathering, indicating that rainwater can play a greater role in determining groundwater strontium composition than is often realised. Most parts of the palaeodrainage system beneath the basalt are preferentially recharged through the volcanoes, as shown by strong downwards hydraulic gradients and groundwater 87Sr/86Sr ratios similar to the least radiogenic basalt groundwaters. However, in the northwestern part, groundwater 87Sr/86Sr ratios are closer to those of the source material of the sediments (Palaeozoic bedrock), indicating that here recharge occurs predominantly in the headwaters where the basalts are absent. In the southern and western sections of the palaeodrainage system there is an upward flux into the overlying basalts, as shown by strong upward hydraulic gradients and elevated strontium isotope signatures in basalt groundwaters. This occurs because lateral groundwater flow in the palaeodrainage system is restricted by shallow subsurface basement ridges, and ultimately discharges to the surface as salt lakes. [Copyright &y& Elsevier]

Summary: Wave setup is the elevated mean water-table at the coast associated with the momentum transfer of wave breaking, which occurs generally over several days. Groundwater responses to wave setup were observed as far as 5km inland in central Maui, Hawaii. The analysis showed that at times of energetic swell events wave-driven water-table overheights dominate low-frequency groundwater fluctuations associated with barometric pressure effects. Matching peak frequencies at 1.7×10−6 Hz and 3.7×10−6 Hz were identified in setup and observed head using spectral decomposition. Similar to tides, the setup propagation through the aquifer shows exponentially decreasing amplitudes and linearly increasing time lags. Due to the longer periods of setup oscillations, the signal propagates deeper into the aquifer (∼10km in central Maui) than diurnal tides (5km) and can therefore provide information on greater length scales. Hydraulic diffusivity was estimated based on the setup propagation. An effective diffusivity of 2.3×107 m2/d is consistent with aquifer parameters based on aquifer tests and tides. A one-dimensional numerical model supports the results of the analytical solution and strengthens the suitability to estimate hydraulic parameters from setup propagation. The methodology is expected to be beneficial to high-permeability coastal environments, such as on volcanic islands and atolls. [Copyright &y& Elsevier]

A sinking of the land surface due to the pumping of groundwater has long been recognized as an environmental issue in the Shiroishi plain of Saga, Japan. Land subsidence can have several negative economic and social implications such as changes in groundwater and surface water flow patterns, restrictions on pumping in land subsidence prone areas, localized flooding, failure of well casings as well as shearing of structures. To minimize such an environmental effect, groundwater management should be considered in this area. In this study, a new integrated numerical model that integrates a three-dimensional numerical groundwater flow model coupled with a one-dimensional soil consolidation model and a groundwater optimization model was developed to simulate groundwater movement, to predict ground settlement and to search for optimal safe yield of groundwater without violating physical, environmental and socio-economic constraints. It is found that groundwater levels in the aquifers greatly vary from season to season in response to the varying climatic and pumping conditions. Consequently, land subsidence has occurred rapidly throughout the area with the Shiroishi plain being the most prone. The predicted optimal safe yield of the pumping amount is about 5 million m3. The study also suggests that pumping with this optimal amount will minimize the rate of land subsidence over the entire area. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The free surface profile and outflow hydrograph for groundwater under conditions of steady uniform recharge followed by recession have been studied in viscous fluid model tests, using a sloping bed with a gradient of 0.2. The data have been compared with the nonlinear Boussinesq model and a modification of that model simulating the outflow seepage surface, obtained from a finite difference solution of the free boundary problem. It is shown that for a given bed slope, there is close to a linear relationship between outflow and storage raised to a power n, where n ranges from almost 2 for zero slopes to just above 1 at a gradient of 0.3. There is also a simple relationship between outflow and storage in the final stage of recession, when a drainage front occurs on the bed. These results lead to simple algorithms for prediction of the outflow under unsteady recharge conditions. [ABSTRACT FROM AUTHOR]

Axisymmetric flow to a well is an important topic of groundwater hydraulics, the simulation of which depends on accurate computation of head gradients. Groundwater numerical models with conventional rectilinear grid geometry such as MODFLOW (in contrast to analytical models) generally have not been used to simulate aquifer test results at a pumping well because they are not designed or expected to closely simulate the head gradient near the well. A scaling method is proposed based on mapping the governing flow equation from cylindrical to Cartesian coordinates, and vice versa. A set of relationships and scales is derived to implement the conversion. The proposed scaling method is then embedded in MODFLOW 2000. To verify the accuracy of the method steady and unsteady flows in confined and unconfined aquifers with fully or partially penetrating pumping wells are simulated and compared with the corresponding analytical solutions. In all cases a high degree of accuracy is achieved. [Copyright &y& Elsevier]

Highlights: [•] We include anisotropy in the new development of the second-order theory. [•] The bank-storage problem is used as test case. [•] A new analytical solution to the second-order theory is presented. [ABSTRACT FROM AUTHOR]

Within the arid Tata River catchment of the Moroccan Anti-Atlas Mountains groundwater is the only source for drinking and irrigation water supply. Nevertheless, the hydrogeological and hydrogeochemical setting of the area is understudied. In order to develop sustainable groundwater management strategies a profound understanding of the region's groundwater system is essential. In terms of comprehensive field surveys, aquifer structure and properties as well as water composition were evaluated. The Lower Cambrian Limestone and Dolomite Series as well as the Quaternary sediments were identified to be the major aquifer systems. Isotopic signatures of groundwater indicate direct groundwater recharge trough fractures and a major flow direction similar to the drainage system of the Tata River. Hydrochemical composition mainly reflects the mineralogy. The primary processes are calcite and bassanite dissolution as well as dedolomitization and feldspar weathering. Water of irrigation return flow drains downstream and is pumped repeatedly, with each cycle contributing to contamination and water loss through evaporation, while the water is used for irrigation and daily needs. In turn, groundwater quality decreases along its flow path from N to S. The hydrogeological conceptual model, visualizing all results, can be used by stakeholders to integrate groundwater related aspects into site-specific agricultural practices as well as to set up numerical flow and transport models. Image 1 • Direct groundwater recharge occurs at elevated areas. • Statistics and ion ratios show feldspar, calcite, and bassanite weathering. • Hydrochemistry and isotopes indicate irrigation water return flow. • Groundwater quality decreases along its flow path from N to S due to human activities. • Hydrogeological conceptual model is a base for a sustainable groundwater management. [ABSTRACT FROM AUTHOR]