•The role of aquifer properties is underestimated in catchment classification.•Bedrock properties are highly relevant to streamflow dynamics.•Geological properties influence the catchment ability to ...buffer the climate signal.•High- and low-flow surface discharge are highly correlated.
Relating stream dynamics to catchment properties is essential to anticipate the influence of changing environmental conditions and to predict flows of ungauged rivers. Although the importance of subsurface processes in catchment hydrology is widely acknowledged, geological characteristics are rarely explicitly included in studies assessing physiographic controls on catchment dynamics. In this investigation of 22 catchments of the Swiss Plateau and Prealpes, we use a simple linear regression approach to analyze the relationship between streamflow indicators and various geological and hydrogeological properties of the bedrock and quaternary deposits, along with meteorological, soil, land use and topographical characteristics. We use long-term discharge percentiles, as well as dimensionless flow duration curves (FDC, standardized by long-term mean discharge) that allow to evaluate the catchment response to climate forcing. While climate conditions dominate the high to medium discharge percentiles (Q5–Q50), the capacity of the catchments to buffer the meteorological forcing can only be attributed to geological characteristics. The sandstone proportion in the catchments explains 54% of the variance of both extremities of the dimensionless FDC (Q5/Qmean and Q95/Qmean) and productive quaternary deposits are responsible of 55% resp. 58% of the variance of the two ratios. Examining the hydrogeological characteristics of both bedrock and quaternary lithologies considerably improves the understanding of catchment dynamics.
This study aims at making a comprehensive assessment of the impact of land use and the hydrogeological properties on groundwater quality. First, factor analysis (FA) is applied to reveal the main ...pollutant sources and hydrogeological processes controlling the groundwater quality. FA identifies the four most important factors. Factor 1 (seawater salinization) is characterized by a medium loading of land use type of aquaculture. It is recognized that the high scores for factor 1 in coastal areas are due to over-pumping from aquafarms. Focused land use management is required to prevent saline-water intrusion in coastal aquifers. Factor 3 (nitrate pollution) shows high correlations with the land use type of fruit farming and the gravel thickness in unsaturated layers. High scores for factor 3 are also found in the proximal area of the Chuoshui River Alluvial Fan and the northeastern mountain area in the Pingtung Plain. Fruit farmers should be educated to reduce the application of fertilizers and promote the organic fruit farming. The impacts of land use and the hydrogeological properties on both Factor 2 (arsenic enrichment) and Factor 4 (reductive dissolution of Fe2+ and Mn2+) are negligible.
Second, cluster analysis (CA) is performed on computed scores of the four main factors to separates 123 monitoring wells into cluster 1 (low polluted zone), cluster 2 (nitrate polluted zone) and cluster 3 (hybrid polluted zone). The results obtained from CA provide practical applications such as reduce agrichemical use in the areas of cluster 2 and enforce intensive monitoring in the prioritizing areas of cluster 3. This study successively uses the FA and CA to extract the meaningful information present by geographical visualization of scores for 4 main factors and 3 distinct clusters zones. The results are essential for formulating sound groundwater resource and land use management policies to ensure groundwater sustainability.
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•FA and CA assess the correlation of land use type, hydrogeological properties and groundwater quality in Taiwan.•Four factors including sea water salinization, arsenic enrichment, nitrate pollution and reduction dissolution of Fe2+ and Mn2+ are identified using FA.•Seawater salinization shows a medium correlation with land use for aquaculture.•Nitrate pollution shows high correlations with land use for fruit farming and the gravel thickness.•CA spatially categorized three clusters including low-, nitrate-, hybrid- polluted zones.
Surface paste disposal (SPD) is a new alternative employed by the mining industry for storage of mine tailings at the surface. In comparison with the conventional slurry tailings disposal, SPD could ...offer operational and environmental advantages, such as a better water management, no need for complex retaining dams, a reduced footprint of the tailings disposal area, and the possibility to use progressive reclamation. This paper describes a field investigation through a large-scale experimental cell to assess an SPD application for sulphidic mine tailings. The work addresses the effect of two disposal configurations (i.e., partially cemented and un-cemented) on their hydrogeological behaviour when submitted to actual climatic conditions, focusing mainly on the implementation challenges as well as on the first results obtained. Tailings were deposited in thin layers (10 layers of 10cm each one) into two experimental cells (D×L×H=8m×15m×2m). Cement was added locally (2wt.% of Portland cement) in the first layer of the cell (CC) to study its effect; the second cell (UC) is cement free. The evolution of volumetric water content Ѳ, suction ψ, oxygen consumption and cracks for each cell was monitored during and after deposition. Results show that the CC provides slightly higher Ѳ and smaller ψ values than the UC, most likely due to its geological properties dictated by the bottom cemented layer.
•Application of surface paste disposal (SPD) was assessed by large-scale field experimental cells.•Effect of disposal configurations (i.e., cemented and uncemented cells) on SPD was investigated.•Evolution of water content, oxygen consumption and surface cracks for each cell was monitored.•The cemented cell provided higher water content and smaller suction than the uncemented cell.•The paste's geological properties were improved by adding the cement locally to the cemented layer.
Nitrogen contamination is a global concern and has been a serious problem in agricultural areas. The present study was carried out in an intensively irrigated region of northwest China along the New ...Silk Road, Yinchuan Plain, where the residents depend on the groundwater as the primary source for drinking. To understand the nitrogen contamination in the aquifer system, the distribution of nitrate and ammonium and its controlling factors were studied based on hydrochemical, hydrogeological, and isotopic analyses. 11.37 and 40% of phreatic water samples are categorized as NO
3
–N and NH
4
–N pollution in accordance with the WHO standards. A total of 59.52% of confined water samples has high NH
4
–N values, exceeding the permissible limit for drinking purpose. The results indicate NO
3
–N predominates in the shallow water and NH
4
–N predominates in the deep water for the single phreatic aquifer. For the multilayer structure area, NO
3
–N predominates in the phreatic aquifer of the western and the southern parts of the plain; NH
4
–N predominates in the phreatic aquifer of the middle and the northern parts of the plain, and in the confined aquifers where groundwater pumping had been performed. The mixture of synthetic fertilizer and manure/sewage is primarily responsible for the phreatic water based on isotopic analysis. In the confined aquifers, higher NH
4
–N concentrations are mainly attributed to intensive pumping under higher pumping rates. The results of this study can be used as a scientific basis for the future research on nitrogen in the plain. They can also be used by scholars and decision makers who are interested in groundwater protection and sustainable development.
Evaporites are typically described as impermeable seals that create some of the world's highest reservoir pressures beneath the salt seal. However, several laboratory studies demonstrate that ...evaporites can retain open pore spaces that hydraulically connect the sediments above and below them in sedimentary basins. During the Messinian Salinity Crisis (5.97–5.33 Ma), up to 2,400 m thickness of evaporites were rapidly deposited in the Western Mediterranean, which may have generated high pore fluid overpressure in the basin sediments. Here we use one‐dimensional numerical modelling to quantify the temporal evolution of overpressure at two distinct locations of the Western Mediterranean, the Liguro‐Provençal and Algero‐Balearic basins, from the Miocene to Present. We reconstruct the sedimentation history of the basin, considering disequilibrium compaction as an overpressure mechanism and constraining model parameters (such as permeability and porosity) using laboratory experiments and the literature. In the Liguro‐Provençal basin the highest overpressure of 11.2 MPa occurs within the halite during deposition of Pliocene to Quaternary sediment, while in the Algero‐Balearic basin at the base of the Emile Baudot Escarpment, the highest overpressure of 3.1 MPa also occurs within the halite but during stage 3 of the Messinian Salinity Crisis (5.55–5.33 Ma). In the Algero‐Balearic basin an overpressure of 3.1 MPa could have been sufficient to hydro fracture the sediments, which agrees with the development of fluid escape features observed on seismic reflection profiles. In general, our models with evaporite deposition rates above 20 m kyr−1 and permeabilities below 10–18 m2, suggest that high overpressure, approaching lithostatic, can be generated in salt basins.
Evaporites are typically described as impermeable seals, however several laboratory studies including this one show that pore fluid flow can occur through them. In this study, we used numerical modelling and laboratory observations of low permeability evaporites to quantify overpressure in the Western Mediterranean from basin inception to present day and estimate overpressure magnitudes triggering fluid expulsion events during the Messinian.
This study presents a comparative, field-based hydrogeological characterization of exhumed, inactive fault zones in low-porosity Triassic dolostones and limestones of the Hochschwab massif, a ...carbonate unit of high economic importance supplying 60 % of the drinking water of Austria’s capital, Vienna. Cataclastic rocks and sheared, strongly cemented breccias form low-permeability (<1 mD) domains along faults. Fractured rocks with fracture densities varying by a factor of 10 and fracture porosities varying by a factor of 3, and dilation breccias with average porosities >3 % and permeabilities >1,000 mD form high-permeability domains. With respect to fault-zone architecture and rock content, which is demonstrated to be different for dolostone and limestone, four types of faults are presented. Faults with single-stranded minor fault cores, faults with single-stranded permeable fault cores, and faults with multiple-stranded fault cores are seen as conduits. Faults with single-stranded impermeable fault cores are seen as conduit-barrier systems. Karstic carbonate dissolution occurs along fault cores in limestones and, to a lesser degree, dolostones and creates superposed high-permeability conduits. On a regional scale, faults of a particular deformation event have to be viewed as forming a network of flow conduits directing recharge more or less rapidly towards the water table and the springs. Sections of impermeable fault cores only very locally have the potential to create barriers.
The mining site in Eastern Anatolia of Turkey were encounter a significant risk of slope instability within the operational area. One of the processes that govern slope stability is the pore water ...pressure distribution. The conceptualization and characterization of porous media serve as fundamental prerequisites for the implementation of numerical methods aimed at predicting pore water distribution. This study aims to characterize the hydrogeological properties of water bearing rocks in the active mining site in Eastern Anatolia of Turkey. A total of 21 wells and drill holes were drilled in the study area to conduct in-situ tests, monitoring, and sampling. The large diameter wells drilled in surrounding the carbonate rocks were to determine the groundwater flow and boundary conditions and also wells tapped metasediments and diorite unit for hydraulic testing. The lugeon tests and installation of vibrating wire piezometers were carried out at small diameter drill holes to obtain localized hydraulic conductivity of metasediments and diorite at different depths and monitoring pore water pressure distribution along some critical cross-sections. The results obtained from these tests are used for developing hydrogeological conceptual model for groundwater flow. The results of in-situ tests show that the metasediment and diorite units act as a single hydrostratigraphic unit. The metasediments and diorite have high total porosity and low specific yield indicating that the pore water is retained by electrostatic forces in the medium and it resists flow due to low hydraulic conductivity. The vertical variation in hydraulic conductivity values indicates that the medium is highly heterogeneous.
Ensuring safe conditions for mining coal under water-bearing sands in the Velenje coal mine depends on the designed parameters of hydrogeology, geomechanics and drainage. The purpose of the research ...is to predict and simulate the hydrostatic pressures above the excavation fields in order to determine the thickness of the insulation layers and the height of the excavation. Coal occurs in the Velenje basin in the form of a slightly concave lens. Directly above the coal seam is an insulating layer of marl or clay. Above the insulating layer are more or less permeable Pliocene sands in which water can accumulate under layer pressure, posing a potential risk of water ingress into underground spaces. In addition to the Pliocene sands, triad layers of different ages and lithology in the bedrock also pose a risk of water intrusion. In order to prevent the intrusion of water into the working areas of underground objects, the criteria for safe mining in the Velenje coal mine under aquifers were established. The scientific research approach to determining the criteria for safe mining enables the safety and determination of excavation heights in coal mining. The following data are required for such a calculation: the water pressure in the first sands, the excavation depth below the surface, the thickness of the insulating layer and the method of excavation or the course of the demolition processes.
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