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This research explores the relationship between aquifer vulnerability, water quality and agricultural and mining activities carried out in a southern portion of the Central Valleys of Oaxaca. This site is located on a shallow aquifer with an average thickness of 30 – 40 m, composed mainly of gravel, sand, clay and silt. These materials constitute the alluvial fill that is considered the main hydrogeological unit, which overlies the metamorphic basement of the Oaxacan complex, which acts as a lower limit restricting the flow of water towards deep infiltration. The study applies a comprehensive methodology, which combines several approaches: the thematic weighting of layers through the DRASTIC method, the analysis of physical–chemical parameters of 145 water samples to determine quality and contamination indices, the interpretation of geological-geophysical data obtained from 11 Transient Electromagnetic Surveys (TEM) that allowed the identification of isoresistive units associated with the geology of the area, these data were complemented with geological field work. The results show that the area dedicated to agriculture has a medium to high vulnerability, with water quality varying from slightly contaminated to highly contaminated, which translates into a moderate to high level of contamination. According to the geological-geophysical interpretation, this area is located in U2b, which presents resistivities that range between 200 and 300 Ohm.m related to alluvial deposits and conglomerates. In the mining activity area, a medium vulnerability was identified, with water quality indices varying from very contaminated to contaminated and contamination levels from moderate to high. The isoresistive unit at this site corresponds to U3, with values greater than 350 Ohm.m, associated with andesitic rocks. At the recharge sites, a low vulnerability was determined, with acceptable water quality indices and low levels of contamination. [ABSTRACT FROM AUTHOR]

The ratio of channel width to channel depth (α) is widely used to quantify the valley geometry of natural alluvial river channels. However, rare studies discussed the feasibility of α to constrain the changes of tectonic and climatic forcing in landscape evolution. To reveal the implication of alluvial valley α values on the effect of rock uplift, we selected an ideal site of the Rumei catchment (RMC) in the mountains of southeast Tibet, where is crossed by the active Lancang River Fault (LCRF) with different spatial characteristics. We used remote sensing, topographic analysis, and grain-size data to analyze channel valley geometry (e.g. valley width, depth, gradient, and α), valley geometry relations and grain-size distribution. Based on the present study, we found that there are three definite groups of α values (α ≤ 4, 4 < α ≤ 6, and α > 6) among the 13 channels in the catchment. The low α group corresponds to alluvial channels at the downstream end of the catchment, where the channels are steep and are controlled by rock uplift driven by thrusting. The medium α group includes channels in the headwaters of the catchment of RMC. High α channels are found in the mid-catchment location of RMC. The time of sediment transport in the mid-catchment has been constrained using radiocarbon ages on organic sediments in alluvial terrace deposits, whose results indicate that the high α channels there were disturbed by a major sediment transport event (debris flows or flood deposits) sometime between 630 and 1991 years ago. We observe that the grain size of deposits is not well related with variation of α values in the study area. We interpreted that the spatial difference of α values is dominantly controlled by the thrusting of LCRF. Hence, we concluded that α is a good indicator of the effect of rock uplift on channel morphology, which could be used to constrain the changes of tectonics in tectonically active mountains. [ABSTRACT FROM AUTHOR]

The opening of Neo-Tethys within Gondwanaland during the Guadalupian (transition signified a pivotal transgressive event) in the Permian Period. Consequently, an attempt has been undertaken to elucidate the sequence stratigraphy and palaeodepositional settings of fluvial sedimentary deposits encompassing coal and shale sediments within the Godavari Valley Coalfield, South India. The Total Organic Carbon (TOC) content across the examined samples exhibits a discernible range from 0.07 to 65.53 wt%, with reactive carbon, measured as Pyrolyzable Carbon (PC), displaying variations from 0.02 to 15.93 wt% and non-reactive carbon, characterized, as Residual Carbon (RC), spans a percentage range of 0–66.86 wt% within the selected samples. The predominant organic matter manifests as type III kerogen, except Sh-47, where type II kerogen is identified. The combination of Rock–Eval pyrolysis alongside palynofacies analysis facilitates the differentiation of significant system tracts arising from relative sea level fluctuations within the deposited terrestrial sequences. These tracts include swampy and flooded palaeomires settings. Terminologies denoting system tracts within the sequences are indicted as T-lst, T-hst, T-tst and T-mfs corresponding to the Low Stand System Tract (LST), High Stand System Tract (HST), Transgressive System Tract (TST) and Maximum Flooding Surface (MFS) respectively. A noteworthy one and half cycles are discerned within the sequence, predicted on Amorphous Organic Matter (AOM), TOC, Hydrogen Index (HI), PC and Gelification Index (GI) values. In the initial cycle, T-mfs is identified based on the preponderance of fluorescent AOM, coupled with the highest value of HI and PC. The ratio of opaque/translucent phytoclasts serves as a discriminant in delineating the boundaries of T-lst, T-tst and T-hst within the sequences, corroborating the aforementioned observation. This research serves as a preliminary assessment of the system tracts within fluvial environments. A more intricate, high-resolution exploration of deeper sequences holds the potential to furnish comprehensive insights for subsequent studies. [ABSTRACT FROM AUTHOR]

To investigate the regular patterns by wind and sand in low hilly basins, we analyzed the particle size, component end element and fractal variability of surface sediments, as well as the near-surface wind energy and sand transport potential, and determined the characteristics of their spatial differentiation in the desert west of Yinshan Mountain in China. The results showed that the regional dominant wind was mainly westerly and southwest wind, and the average annual average wind speed of sand wind was 6.56–7.62 m s–1, the annual average drift potential of the sand wind was 359.99 VU, and the average annual value of synthetic drift potential was 204.46 VU, which classified region as a the middle-wind-energy environment with middle-wind-direction variability. Under the action of dominant wind, the particle size of dune sediment gradually refined from the northwest to the southeast and northeast, and the fractal dimension gradually increased. The sediments of Baiyinchagan Desert, Boketai Desert, and southern Yamaleike Desert dunes were fine (the average particle size was 0.191 mm), and the average fractal dimension value was 2.372; the Haili Desert and the northern Yamaleike Desert dunes was large (the average particle size was 0.212 mm), and the average fractal dimension was 2.327. At the same time, fed by the near source Gobi coarse sand, under the action of long-term wind and sand, the Haili and Yamaleike Deserts formed tall and stable crescent sand dunes and sand dune chains. The particle size end member indicated that the desert sediment was wind deposit, while the desert peripheral Gobi desert end member indicated that the type of sediment was wind deposit and river alluvial material formed under the combined action of wind and water, the heterogeneity of the Gobi outside the desert was significantly higher than the desert surface, which showed moderate spatial differentiation. The topography of low mountains and hilly basins affected near-surface sandstorm processes and the formation and evolution of sandstorm landforms. [ABSTRACT FROM AUTHOR]

A hydrogeochemical study was carried out on the shallow Catania Plain alluvial aquifer, in eastern Sicily to reconstruct its hydrogeological structure, the meteoric recharge and to assess the influence of human activities on groundwater. To characterize the geochemistry of the shallow aquifer, two sampling campaigns were carried out, August–October 2004 and April–May 2005 in 47 sites distributed throughout the plain. The samples were collected and analyzed for physical–chemical parameters and major ions, as well as stable isotopes (δ18O and δ2H). Alluvial deposits with heterogeneous grain sizes constitute the aquifer. Varying conditions of vertical and horizontal permeability lead to the presence of a multilayered aquifer with different conditions of confinement and partial interconnection among layers. The sampled waters were separated into four groups of different compositions due to the water–rock interaction with the different lithologies present in and around the study area. Maps of electrical conductivity and sulfate show a systematic control of land use, in correspondence with the biggest farms. High sulfate concentration is due to both the natural interaction between local meteoric waters and Etna's plume and the mixing with groundwater coming from the area where evaporitic rocks of the Gessoso Solfifera formation are present. In addition, anthropogenic contamination cannot be ruled out. A rain gauge network, consisting of 3 sites located at different altitudes, was installed to collect rain waters to determine isotopic data (δ2H and δ18O) and to measure the monthly rainfall amount. Based on the isotopic composition of sampled waters, it has been established that beyond the direct meteoric recharge, the recharging areas are in the North (Mt. Etna) and the South (Hyblean Plateau). [ABSTRACT FROM AUTHOR]

Throughout the world, mountain populations have developed specific agroecosystems, with different types of water supply for irrigation and domestic use. The Drave mountain village (North Portugal) has, for centuries, faced harsh hydrological, hydrogeological, and hydropedological conditions. Since the second half of the twentieth century, the nature of water demand in Drave has drastically changed. The research objective is to understand the evolution of water demand and supply in the village of Drave, from the sixteenth century to the present day, and to present a possible solution to meet future water needs. A sampling network, comprising surface water and groundwater points, was established. Then, a sampling campaign took place in the dry season, and another one in the wet season. Laboratory analysis encompassed major inorganic ions, Potentially Toxic Elements, and microbiological parameters. Groundwater vulnerability to pollution was assessed through the DRASTIC index and GVTool, a Geographic Information System open-source application. Two historical periods were identified concerning the Drave water demand and supply: (i) from the foundation of the village until the second half of the twentieth century; (ii) from the mid-twentieth century on. The current scenario consists of using water resources with chemical and microbiological contamination to supply the needs of temporary inhabitants. Groundwater vulnerability to pollution ranges from extremely low to moderately low, with the most vulnerable areas corresponding to valley bottoms. A possible solution to meet the future water demand consists of abstracting and treating only surface water during the wet season and taking advantage of the hydrological regime of stream alluvial deposits during the dry season. [ABSTRACT FROM AUTHOR]

The aim of this work was to show how to construct maps of anthropogenic contamination of agricultural soils in Czech Republic by risk elements. The geochemical datasets for this work originated from state monitoring utilising acid extractions according to past and present national legislative requirements. The goal was to distinguish contamination from natural variability respecting knowledge in environmental geochemistry and available information sources. Conventional approaches to geochemical maps, such as plotting sampling points where element concentrations exceed Tukey or Carling upper fences (boxplot approach), can be used to visualise only extreme contamination, such as historical ore mining and processing. The challenge starts when weak and/or diffuse contamination is of interest and should be distinguished from natural variability. Geogenic anomalies in Czech Republic are represented by mafic volcanic rocks (Cd, Cu, Zn), metamorphic rocks (As, Zn), felsic intrusive volcanic rocks (Pb, Zn), and variegated rocks showing volcanic components (Cd, Pb, Zn). Lithological anomalies are typical for floodplain sediments of lowland rivers. Each cumulation of concentrations above the Tukey or Carling upper fences within the whole-Czech dataset, i.e. potential contamination hotspot, should be examined in detail to judge possible natural controls. Pleistocene and Holocene sediments, in particular aeolian and fluvial deposits with their specific grain size, represent an important controlling factor in such detailed maps. Element concentration ratios in rational subcompositions, e.g. including Co, Cu, Pb, and Zn, were found useful to separate geogenic and lithogenic anomalies, In this subcomposition, Co is promising reference element for datasets obtained by conventional acid extractions as a surrogate for missing analyses of lithogenic elements. There is no automated way of distinguishing anthropogenic contamination from natural variability for weak contamination, expert opinion is indispensable to distinguish natural and anthropogenic factors. The larger (more heterogeneous) the mapped areas, the more complicated interpretation of their geochemical maps and less reliable identification of anthropogenic contamination. Zooming in and examination of empirical cumulative distribution of element concentrations for the zoomed areas is the most powerful tool in converting geochemical to contamination maps, assuming the zoomed areas are covered by relatively homogeneous soils, with small number of soil-forming bedrock and not much geomorphic heterogeneity. [ABSTRACT FROM AUTHOR]

The study area of Cala Gonone in NE Sardinia (Italy) consists of a wide terraced re-entrance/valley crowned inland by carbonate hills and, near the coast bounded laterally and partly floored by thin basaltic lava lying over carbonate bedrock. In this re-entrance, several inland alluvial fans (500 m length by 700 m wide) have developed, and a local ~ 30 m high, about 10 m wide (thick), 400 m long scarp body-remnant of semi-consolidated alluvial fan deposits is exposed along the coast. The fans experience depositional events mostly developed during the late Pleistocene. They although nowadays dormant may be reactivated by major rainstorms during strong climate changes. In these last few decades, the touristic village of Cala Gonone has been rapidly expanding over the mid to lower parts of two coalescing alluvial fans (Stadium and Gustui) and along the coastal marine scarp edge (Palmasera alluvial fan system). The village thus may become exposed to natural hazards if extreme climatic conditions may re-occur. Moreover, rock falls and the instability of the costal scarp due to wave erosion may add addition hazards for habitations built near the scarp crest and visitors to the frontal replenished beach. As commonly occurring elsewhere since antiquity, the risk perception of such events is low because of the centennial, millennial of longer recurrence. Such perception does not negate the hazards but a long event recurrence may be accepted as a reasonable risk for the human's activity. Nevertheless, serious consideration should be given to potential problems and plan and build for amelioration and defense. The evidence of what environmentally did and could still happen in the Cala Gonone and similar other area is in part clearly imprinted on the landscape: geology, geomorphology, and relative details in the stratigraphy and sedimentology of the deposits. [ABSTRACT FROM AUTHOR]

The northeastern part of India is seismically very active due to the ongoing Indian Plate under-thrusting and rise of several mountain ranges. As a result, the Himalayas, Naga Hills, Shillong-Karbi Massifs, and the Assam Valley have many crustal-scale active faults. These faults often cause moderate to large earthquakes while releasing the accumulated stress associated with Plate tectonics. In this study, one such major earthquake event of Mw 6.0 occurred near the Kopili Fault and Himalayan Frontal Thrust in the eastern Himalayan foreland region on 28th April 2021. The event has been investigated to understand its seismotectonic and environmental impacts. The quake caused much damage in the epicentral area around Dhekiyajuli of Sonitpur District, Assam, India. The densely populated Guwahati and Tezpur cities of Assam have suffered damage as some parts of buildings and roads were collapsed. Moreover, a landslide near Bhairabkunda and several liquefaction incidents near Tezpur and Dhekiyajuli localities were also recorded, within 30–50 km from the epicentre. It is found from NASA's GRACE-Land data that the increase in groundwater volume on the northern bank of the Brahmaputra than the previous year might be related to higher rainfall in the recharge zone around the Himalayan Frontal parts. Such groundwater conditions caused saturation of the subsurface soil and alluvium, which resulted in the formation of liquefaction during high shaking. These incidents also caused severe environmental damage. After the earthquake, the sprouting of mud water affected rice fields and nearby freshwater sources like ponds and lakes. This earthquake, along with the historical ones, reveals the vulnerability of the entire region to many natural hazards. This study provides a scope to understand the seismotectonic and environmental exposure of the eastern Himalayan foothill region. [ABSTRACT FROM AUTHOR]

We analyze the evolution of the undeformed Middle to Late Pleistocene deposits of Es Codolar (Southern Eivissa, Western Mediterranean). The outcrop records a succession characterized by the alternation of aeolian, colluvial and alluvial fan deposits and palaeosols that result in a complex stratigraphic architecture. In this area, aeolian beds, colluvial deposits and palaeosols are exposed along sea-cliffs for almost 500 m, allowing detailed descriptions both of the general sedimentological and geomorphological features of the Middle to Late Pleistocene deposits. Several different types of soft-sediment deformation structures are described (load-casts structures, injection structures, water-scape structures, rizoconcretions), which will help us in the understanding of the climatic evolution and the syn- post-depositional processes. In this way, main processes triggering the formation of these structures seem to be sea level changes together with a wetter environment during warmer climatic episodes. [ABSTRACT FROM AUTHOR]

The failure of vertical concrete shafts in the deep alluvium zones is always a troublesome technical problem in coal mines. There is lack of practical failure criteria for such shafts. Therefore, the method of establishing failure criteria of shafts based on the method of ultimate strain was proposed. By regarding concrete as a frictional geomaterial, the formula for the plastic ultimate strain of concrete was constructed according to the theory of generalised plastic mechanics. Furthermore, the ultimate strain when concrete failure was determined using numerical limit analysis method. The numerical limit strain analysis method can be used as a quantitative failure criterion for a concrete shaft. It can directly determine the limit state and failure position. By exploring the shaft deformation during the reduced groundwater level of quaternary aquifers by applying numerical limit analysis method, the failure procedure of concrete shaft was reproduced. It was revealed that the damage to the soil around the shaft preceded that to the shaft; the reduction in groundwater level of aquifers can damage the shaft, while the stress-relief groove delays the failure of the shaft and shifts the failure zone to a greater depth. On condition that water level decreased by 25 m, the sand layer at a burial depth of 158–174 m was damaged; in the case that water level was reduced by 27 m, the shaft at a burial depth of 181–182 m was damaged. After setting a stress-relief groove on the shaft, failure occurred when the groundwater level was decreased by 38 m, implying that the stress-relief groove can release the vertical stress on the shaft. [ABSTRACT FROM AUTHOR]

Groundwater is the major source of drinking water on the earth's surface. The threat to groundwater contamination is increasing day by day due to rapid increase in industrialization and urbanization. The present study aims at assessing the groundwater quality contamination threat around industrial cluster at Rajasthan State Industrial Development and Investment Corporation (RIICO) in Jaipur district of Rajasthan, India. The cluster does not have common effluent treatment plant, and very few units have their effluent treatment plants. Groundwater samples were collected around the industrial cluster and its vicinity and analyzed for major cations, anions and trace elements. The water quality data indicate that total dissolved solids exceed the drinking water standard set by the Bureau of Indian Standards in few samples, and trace elements of health significance are not detected in any sample. The soil analysis indicates that only the top surface near the point of disposal of the treated effluent is affected. In view of the thick alluvium of 60-80 m and the water table above 30 m, the effluents are retarded significantly before reaching the water table. The sodium adsorption ratio of water samples indicates its suitability for irrigation and falls in the category of fairly suitable to excellent. Piper plot reveals that dominant cations are Na, K and Mg and dominant anions are $${\text{HCO}}_{3}^{ - }$$ and $${\text{CO}}_{3}^{ - }$$ . The Gibbs plot indicates that rock-water interactions influence the groundwater quality. The study reveals that the groundwater quality from most of the sources meets the requirements of drinking water standards, and there is enough environmental space available for the expansion of industrial belt in this RIICO hub. [ABSTRACT FROM AUTHOR]

Cuejdel Lake in the Eastern Carpathians (Romania) formed in 1991 following the damming of the Cuejdiu brook from torrential rainfall causing a massive landslide of natural deposits. In 2011, using a Bathy-500DF Dual Frequency Hydrographic Echo Sounder, the first detailed bathymetric model of the lacustrine cuvette was produced, using more than 45,000 depth readings. This was the first ever use of a Ground Penetrating Radar (GPR-a Malå Ramac X3M GPR with a 100 MHz antenna) in Romania for evaluating the rate of clogging of a dam lake. The thickness of the alluvial deposits and the rate of clogging were determined on the basis of the measurements taken in wintertime, when the ice cover was 30-45 cm. The data concerning the clogging were correlated with the solid transport from the level of the catchment basin developed in the flysch area, and with the sedimentation conditions of the lake (the analysis of the annual non-glacial varve, in situ biodegradation). The morphologic evolution of the lacustrine cuvette, determined on the basis of three DEMs, revealed a significant quantitative dynamics of the alluvial deposits (sediment accumulation rate 1-16 cm/year; volume of sediments across bathymetric levels 33.6-440.4 m/an; total volume accumulated in 22 years 103,988.87 m, which represents 8.5 % of the initial volume (1,223,001.33 m); average annual clogging rate 4521.26 m/year or 0.36 %/year). In 2004, Cuejdel Lake was declared a protected natural area; accordingly, no hydrotechnical works can be carried out in order to stop the erosion and, implicitly, the clogging. [ABSTRACT FROM AUTHOR]

Application of remote sensing and geographical information system (GIS) with the help of ground truth studies like vertical electrical soundings (VES) and water quality measurements gave a comprehensive picture on saline water intrusion pathways in the structural controlled aquifers of Uppanar and Cauvery River systems located in Sirkazhi and Mannanpandal coastal areas of Southern India. The detailed geomorphic units and lineaments were mapped using IRS LISS-III (1:50,000 Scale) and SRTM Elevation Digital data under GIS environment. The area is mainly alluvial deposits of Holocene Age and classified into three major geomorphic units (i.e., fluvial, fluviomarine, and marine geomorphic units). The identified lineaments are mostly trending North-northeast (NNE)-South-southwest (SSW), Northeast (NE)-Southwest (SW), Northwest (NW)-Southeast (SE), East-West (EW) and East-Northeast (ENE)-West-Southwest (WSW) directions. Some of them are potential for fresh groundwater occurrence and movement. The lineaments trending NE-SW, NNE-SSW, and ENE-WSW act as pathways for saline water intrusion to the inland. The lineament L1 (NNE-SSW trending) conformed as a sinisterly shifted fault played a significant role in saline water intrusion. The area within the parallel lineaments L2 and L3 oriented ENE-WSW direction indicates low topography, beach ridges, paleo-channel sinuosity, large aerial extent of tidal flats, and backwater inundation. All the above geomorphic units gave indirect evidence of land subsidence, which was confirmed with the help of sub-surface geo-electrical signals obtained through VES and in situ groundwater quality measurements. Integrating all the above results, the saline water spread and fresh water pockets were identified. [ABSTRACT FROM AUTHOR]

Subsurface dams could be an optimal solution for storing floods or waters of temporary streams in countries with arid and semi-arid climatic conditions. Many such structures are already completed in the northern and eastern African countries and Middle East, but many other prosperous locations require feasibility assessment and construction if found appropriate. Two types of dams are common: one built in the karst (for direct recharge), and the other into the karst connected alluvial aquifer (for indirect recharge). The former is very rare due to its complicated construction and threat of water leakage. The latter has more often, but not always been applied with the aim to improve storage in karst, but as an indirect effect of damming of the flow in adjacent alluviums. This article discusses some positive experiences with dams built in northern Iraq, Algeria, Ethiopia and Somalia and advantages of the application of such subsurface structures in several potential locations in countries with a prevailing arid and semi-arid climate, but it also explores uncertainties which end-users may face if the engineering design is not prepared based on results of a proper research programme. [ABSTRACT FROM AUTHOR]

Electrical Resistivity Imaging (ERI) and Ground-Penetrating Radar (GPR) methods were utilized in this study to identify soil profiles around Necatibey Subway Station of Kızılay-Çayyolu metro line, Ankara, Turkey. The Necatibey Metro Station is located within the alluvial deposits of Dikmen stream and the so-called Ankara clay. At the metro station, a number of boreholes were drilled. However, due to the spacing of the boreholes the boundary between alluvium and Ankara clay deposits could not be separated precisely. Thus, in this study, ERI and GPR methods were utilized to distinguish soil types at the study area. GPR measurements were taken from a total of 14 profiles and total length of the profiles was about 320 m. For every ERI measurement section, Schlumberger Dipole-Dipole, Dipole-Dipole, Schlumberger and Wenner arrays were used. Results from the geophysical measurements identified that the fill materials are underlain by the Dikmen stream channel deposits, which consist of silty clay and gravelly sand units. The study also shows that the Dikmen stream channel deposits are underlain by the Ankara clay unit. The meaningful range of resistivity values was between 1 and 15 Ωm, and the GPR signals were strong in sandy units while they attenuated in clayey environments. Based on borehole logs, ERI and GPR data, three-dimensional lithological subsurface model of the survey area was constructed. The resultant three-dimensional diagrams may serve engineers as a practical tool during different construction stages, groundwater-surface water interactions within short and long term, and probable remedial measures. [ABSTRACT FROM AUTHOR]

The Appalachian Plateau is characterized by relatively flat-laying but intensely eroded bedrock, comprising cyclical sequences of Pennsylvanian age sedimentary bedrock dominated by sandstone, siltstone, shale, coal, claystone and occasionally limestone. Fractured/weathered sandstone is potentially the main groundwater transmitting zone. Conventional field or laboratory methods of estimating the hydraulic properties in selected points within such fractured and weathered bedrock groundwater transmitting zones are seldom representative or feasible because of their heterogeneity, anisotropy and irregular aquifer geometry. Therefore, the objectives of our study is to determine the 'bulk' hydraulic properties of a weathered/fractured zone in a valley located within the Appalachian Plateau Geomorphic Province as well as recharge and evapotranspiration rates by inverse numerical simulation of groundwater flow. [ABSTRACT FROM AUTHOR]

In the present work, non-invasive microtremor survey is applied for the preliminary characterization of the thermal district of Caldiero, in the eastern Po Plain (Italy), a thermal resource known since the Roman times for the presence of warm springs. The work's aim was to test the suitability of the microtremor passive technique for the preliminary characterization of a thermal basin, in terms of resonance properties between the alluvial deposit covers and the rocky bedrock. In particular, the horizontal-to-vertical spectral ratio (HVSR) single-station technique is adopted to estimate the resonance properties of the geothermal basin. More than 100 HVSR single-station measurements are collected and analyzed in the area studied. HVSR information is integrated with the findings of the analysis of the data relative to more than 20 deep wells. Such an integration permits the calibration for validation of the geophysical data. The correlation between the results from microtremor survey, LiDAR data analysis, and wells information highlighted the main geological structures of the site, which are potentially responsible for the thermal waters arising. HVSR results are then interpreted in terms of regional geological setting, textural, and hydrogeological properties of the superficial deposits and the underlying rocky bedrock. The results of this method confirm the existence of significant correlations between the resonance behavior of the basin, as determined by the HVSR technique, and the geological assessment. This suggests that the single-station technique could be a very promising tool for a rapid and preliminary non-invasive method for the near-surface general characterization of geothermal basins. [ABSTRACT FROM AUTHOR]

Hydrogeochemical investigations have been carried out in the Jalandhar District, Punjab, India to decipher hydrochemistry and groundwater quality for its suitability for drinking and irrigation purposes. Most of the irrigation practices depend on shallow or deeper tube wells as an alternative source to the surface water, and consequently rapid decline of the groundwater levels. Based on sodium absorption ratio, %sodium, chloro-alkaline indices are CAI-I, CAI-II and Permeability Index results, most of the groundwater samples collected in the study area were good for drinking and irrigation purposes. The hydrochemical facies suggested that the fluids interacted with carbonate minerals and have not been significantly altered by cation exchange, dissolution of evaporates, and/or mixing with more evolved waters. The analysis of Gibbs plot indicated the groundwater chemistry controlled by weathering process of silicate minerals. The aim of the study was to assess the spatial distribution of hydrogeochemical parameters and to determine controlling factor of geochemical process of the water composition based on the major ion chemistry of 44 groundwater samples collected in the study area. [ABSTRACT FROM AUTHOR]

Analysis of boron within groundwater was undertaken for an area of Central Eastern Italy. Although boron is a minor analyte in groundwater, concentrations can often be above limits set by legislation. A hydrogeochemical study, supported by a statistical multifactorial analysis, was undertaken to investigate the most likely origin of the boron within the groundwater. It was possible to distinguish contamination caused by anthropogenic activities from natural pollution within the study. Hydrochemical analysis has highlighted that anomalous concentrations of boron are only seen in groundwater from the alluvial valley deposits. A strong correlation between high boron concentrations and groundwater with chloride-sodium facies was also identified. The principal components analysis has confirmed the results from the assessment undertaken with hydrochemical analysis. The most important component is characterised by high loading of boron, sodium, chloride and electrical conductivity. The most likely origin of the boron within the hydrogeochemical context of the area appears to be connected to the uprise of chloride-sodium connate groundwaters naturally enriched in boron. [ABSTRACT FROM AUTHOR]

Assumptions of simple geometries for alluvial deposits (related to main rivers) can preclude determination of complexities that are revealed as fundamental controls in underground flow. Although subhorizontal contacts between alluvial and substratum materials are expected, previous sedimentary or erosional processes can result in irregular geometries, only accessible through detailed analysis. The studied case presents the 3D reconstruction of a Quaternary terrace in the proximities of Sabiñánigo (Southern Pyrenees, Northeastern Spain), lying on homogeneous Eocene marls. The studied area is located in an industrialized area supporting strongly pollutant chemical industry (chlorinated pesticides) for the past 50 years. The objective of the study was to constrain the groundwater pathway along the area to subsequently analyze leakage of chemicals to the water table. In order to reveal preferred flow paths, a detailed characterization of the internal structure of the alluvial deposits (0.5-13 m thick) and their relations with the Tertiary substratum was carried out by means of ground penetrating radar (GPR, 50 and 100 MHz antennas). The obtained models permit identifying several topographic highs in the alluvial/substratum contact, determining preferred pathways in water flow, favoring particular conditions associated with low levels of the water table. The presented results support the interest of application of GPR surveys in order to characterize the groundwater pathways in expected homogeneous areas and their importance in order to establish the contaminant surveillance network. [ABSTRACT FROM AUTHOR]

A geomorphologic and morphometric analysis was performed to determine the characteristics of the de La Flecha river basin, located in the southwest of San Juan province (31°50′S, 68°57′W), Precordillera of San Juan. The drainage networks were derived from shuttle radar topographic mission (SRTM), satellite imageries (Landsat TM and Spot image) and field works. The paper also addresses a preliminary evaluation of the flood hazard responsible for severe damage to people and infrastructure in the downstream region. The study area covers about 300 km, comprising of six sub-watersheds, ranging from 31.7 to 81.8 km. The irregular morphology of the basin and the diversity of alluvial deposits found along the de La Flecha river allow the authors to infer that it is in an active tectonic environment with strong lithological and structural controls. One feature common to all analyzed sub-basins is their elongated shape, which allows for a rapid concentration of water that intensifies the power of the flash floods. The drainage network in the different sub-basins has, in general, two predominant patterns; one is parallel to sub-parallel to the headers and foothill areas; and the other, in the alluvial zone, is divergent. Los Berros, Cañada Honda and Media Agua towns, located downstream of the basin, are the most affected by flash floods coming from the mountainous area. [ABSTRACT FROM AUTHOR]

The Guarani aquifer system (GAS) represents one of the biggest aquifers in the world and is the most relevant groundwater resource in South America. For the first time, by combining field and laboratory measurements, a high-resolution aquifer analog model of fluvial-aeolian sediments of the GAS in São Paulo State (Brazil) is constructed. Three parallel sections of frontal outcrops, 28 m × 5.8 m, and two parallel sections of lateral outcrops, 7 m × 5.8 m, are recorded during open-pit mining of sandy sediments and describe in detail the three-dimensional distribution of the local lithofacies and hydrofacies. Variations of hydraulic conductivity, K, and porosity, n, are resolved on the centimeter scale, and the most permeable units of the fluvial-aeolian facies association are identified. The constructed aquifer analog model shows moderate hydraulic heterogeneity and a mean K value of 1.36 × 10m/s, which is greater than the reported range of K values for the entire GAS in São Paulo State. The results suggest that the examined sedimentary unit constitutes a relevant portion of the GAS in São Paulo State in the context of groundwater extraction and pollution. Moreover, the constructed aquifer analog is considered an ideal basis for future numerical model experiments, aiming at in-depth understanding of the groundwater flow and contaminant transport patterns at this GAS portion or at comparable fluvial-aeolian facies associations. [ABSTRACT FROM AUTHOR]

This study is focused on the management of coupled groundwater-river interaction (GRI) in the context of inter-basin transfers. The semi-coupled models, HEC-RAS and MODFLOW, were utilized in this study to replicate the River Tees experiment that had been conducted in 1976. Then the 'surrogate' models were applied to two 'what if' scenarios in order to understand and manage GRI behavior and the nature of the reservoir control system. The results on the River Tees showed that the total temporary bankside storage volume was up to 17.5 % of the total reservoir release, given about 22 h of travel time. In addition, zones 4 and 5 of the river model with significant alluvium deposits were the best storage sites with values of 4.5 and 6.7 % of the total reservoir release, respectively, estimated as temporary losses. The final direct runoff received downstream at broken scar was about 95 % of the Cow Green total reservoir release. Furthermore, the closure rate proved to be vital to compute the effective return flow in respect of this study area. Finally, with careful reservoir and groundwater management, the River Tees proved to be an ideal natural aqueduct for inter-basin transfers when used as part of a major regional water resources scheme. [ABSTRACT FROM AUTHOR]

Fluvial suspended sediment has multi-fold environmental implications and the study of the variation in suspended sediment load (SSL) of rivers is important both in environmental earth sciences and in river environmental management. Based on data collected for the upper Yellow River of China in the past 50-60 years, the purpose of this study is to elucidate the impact of human activity and climate change on SSL, thereby to provide some knowledge for the improvement of the drainage basin management. The results show that the SSL of the upper Yellow River exhibited a remarkable decreasing trend. A number of reservoirs trapped a considerable amount of sediment, resulting in a reduction in SSL at Toudaoguai station, the most downstream station of the upper Yellow River. The analyses based on Mann-Kendall'U and double-mass plot indicate some turning points, which were caused by the Liujiaxia and Longyangxia Reservoirs, two major reservoirs on the upper Yellow River. The implementation of soil and water conservation measures reduced the runoff coefficient, and therefore, the intensity of soil erosion. The climate change also played a role in reducing sediment yield. The increase in air temperature enhanced the evapo-transpiration and reduced the runoff, by which the SSL decreased. The decreased frequency of sand-dust storms reduced the amount of wind-blown, sand and dust to the river reaches located in desert, also reducing the SSL. Seven influencing variables are selected to describe the changing human activity and climate. As some of the influencing variables are strongly inter-correlated, the principle component regression was used to establish the relationship between SSL and the influencing variables. The squared multiple correlation coefficient is R = 0.823. Some further research is suggested with the minerals and pollutants related with the SSL. [ABSTRACT FROM AUTHOR]

Stratigraphic heterogeneity is a key controlling factor for flow and transport in groundwater systems. In this case study, we have combined two- and three-dimensional images of electric resistivity with hydrogeological data to delineate such stratigraphic heterogeneity at a loop of River Steinlach close to Tübingen, Germany, where we estimated spatially varying aquifer parameters using established evaluation techniques. We developed a three-layer stratigraphic model consisting of heterogeneous sandy gravel overlain by a fine alluvium including top soil, and underlain by sandstone weathered at its top. The sandy gravel makes up the aquifer unit while we interpret the sandstone as aquitard. We classified the area into two stratigraphic segments based on resistivity data. The Southern segment consists of a thicker alluvium where the aquifer material contains more clay than in the Northern segment. Two different stratigraphic structures were also delineated at the Southern and Northern segments, respectively. These structures are visible in inversion results as low-resistivity features trending in the SE-NW in the Southern segment and NE-NW in the Northern segment. Both structures may be previous flow paths of River Steinlach, and the low permeability material overlying them may impair flow exchange in the area. We performed slug and pumping tests to estimate the hydraulic conductivity ( K) of the aquifer. The K distributions show slight variation with higher values obtained at wells within the Northern segment and close to the river bank. A qualitative comparison of measured hydraulic conductivities with the resistivity distribution shows good agreement of the spatial patterns. The stratigraphic and hydraulic heterogeneities delineated in this work are important for experimental and modeling studies of flow, transport, and hyporheic exchange at the site. [ABSTRACT FROM AUTHOR]

Liquefaction of the soils is a major problem during and after earthquakes, and can lead to severe damage. A wide range of experience in dealing with natural hazards was gained in the capital city of Ankara after several earthquakes occured in Kaman (1938), Gerede (1944), and Duzce (1999), and in later events. The recent findings after the Orta (2000) and Bala (2005, 2007) earthquakes proved that Ankara should not be designated as a nonseismic hazard zone, as it has been previously. The Quaternary age alluvium is located in the nearby suburbs of Etimesgut, Macunkoy, Cuglu, Avdan, and Kazan. A high density of population and structures is spread over this alluvium, which contains a high percentage of cohesive soils associated with sand and gravel lenses. The depths of the groundwater level ranges between 6.0 and 8.0 m in west Etimesgut, 3.0 m in Macunkoy, 5.0 to 7.0-8.0 m in Cuglu/Avdan, and 4.5-7.0 m in southern Kazan. The average S wave velocities of the alluvium derived from the ReMi were 140 m/s in Etimesgut, 200 m/s in Macunkoy, 134 m/s in Cuglu/Avdan, and 200 m/s in Kazan, respectively. Liquefaction evaluation is conducted by standard penetration blow count, shear wave velocity, and threshold acceleration. Varying horizontal accelerations of the input motions in the soil stratigraphy were generated via the Quad4m program. Geotechnical investigation and proper soil improvement should be carried out in order to prevent structural damage. [ABSTRACT FROM AUTHOR]

The relationship of soil gas radon Rn and indoor radon was studied within the Quaternary fluvial sediments of the Czech Republic. The processing of data selection from the radon database of the Czech Geological Survey and indoor radon data (database of the National Radiation Protection institute) has proved the concentration dependence of radon in Quaternary fluvial sediments on deeper bedrock. The ArcGIS processing was accompanied by the field verification in five profiles, intersecting the granitoid Central Bohemian Plutonic Complex and its rim rock types. Both theoretical and experimental results show dependence of soil gas radon and indoor radon concentrations in Quaternary fluvial sediments on deeper geological basement, thus leading to the conclusion that the lateral transport of Quaternary sediments does not play such a dominant role in radon concentrations, as was thought previously. This fact will enable to determine precisely the radon index of Quaternary sediments (in the Czech radon mapping classified as an intermediate index) into three categories according to the lithology of their geological basement. [ABSTRACT FROM AUTHOR]

The Mike Horse Mine tailings dam in western Montana was partially breached in 1975 due to heavy rainfall and a failed drainage bypass. Approximately 90,000 tons of metal and arsenic-enriched tailings flowed into Beartrap Creek and the Blackfoot River. The spatial distribution of trace elements As, Cd, Cu, Mn, Pb, and Zn in floodplain alluvium of the upper Blackfoot River were examined along 20 transects in the upper 105 river kilometers downstream from the tailings dam. Trace element concentrations decrease with distance from the failed dam, with As reaching background concentrations 15 km from the Mike Horse dam, Cd and Pb at 21 km, Cu at 31 km, and Mn and Zn at 37 km. Distance from the Mike Horse tailings dam and mine area is the dominating factor in explaining trace element levels, with R values ranging from 0.67 to 0.89. Maximum floodplain trace element concentrations in the upper basin exceed US. EPA ecological screening levels for plants, birds and other mammals, and reflect adverse hazard quotients for exposure to As and Mn for ATV/motorcycle use. Trace element concentrations in channel bank and bed alluvium are similar to concentrations in floodplain alluvium, indicating active transport of trace elements through the river and deposition on the floodplain. The fine fraction (<2 mm) of floodplain alluvium is dominated by sand-sized particles (2.0-0.05 mm), with Cu and Mn significantly correlated with silt-sized (0.05-0.002 mm) alluvium. Ongoing remediation in the headwaters area will not address metal contamination stored downstream in the channel banks and on the floodplain. Additionally, some trace elements (Cu, Mn and Zn) were conveyed farther downstream than were others (As, Cd, Pb). [ABSTRACT FROM AUTHOR]

Modern fluvial deposits from both small and large rivers were studied at 14 monitoring sites over 2 years (4 successive sampling seasons) in the area of eastern Moravia (Czech Republic). Grain size, geochemistry, content of persistent organic pollutants (PAHs, PCBs, HCHs, DDTs, HCBs and PeCB) and TOC were examined with the aim to understand their mutual relations and seasonal variations in sediment character and pollutant content. Sand and silt fraction predominate and the clay content is relatively low. Differences in provenance for various river systems were recognised. Both regional and seasonal variations in terms of content of persistent organic pollutants were documented. The content of TOC and mud was shown to play an important role in the accumulation of chlorinated persistent organic pollutants PCBs, HCHs, DDTs and HCB. [ABSTRACT FROM AUTHOR]