Quaternary Gravel Research Articles

Thermal conductivity in a vadose zone: A novel spectral solution and application by the implication of significant coherence of thermal condition in the shallow soil water layer

AbstractIn the context of the heterogeneity in the unsaturated or vadose zone, accurately representing the analytical mechanisms and in‐situ water content within the soil layer poses a significant challenge. Particularly in shallow layers, thermal conditions exhibit rapid changes in response to evolving surface temperatures. This study proposes a hypothesis suggesting that the in situ heat mechanism may notably impact the soil water layer. The research introduces an innovative approach to theoretically uncover thermal conditions, including soil temperature, soil temperature gradients, and heat flux, within the shallow Quaternary gravel layer at various depths through spectral analysis of temporal observations. The study presents a stochastic inverse solution to estimate thermal conductivity by leveraging spectral analysis of soil heat flux and temperature gradients. The findings reveal that thermal conditions exhibit the most prominent periodic fluctuations during the diurnal process over a 24‐hour cycle. The soil temperature gradients and heat flux measurements at depths of 0.1, 0.3, 0.6, and 1.2 m demonstrate their ability to capture changes in soil temperature and air temperature to a certain extent within the frequency domain. Furthermore, the analysis highlights the intrinsic uncertainty and sensitivity of estimating thermal conductivity in heterogeneous soil environments. The wide variability observed in thermal conductivity values, coupled with their dependence on soil type and environmental conditions, underscores the need for careful consideration of these factors in future studies and modeling efforts. Applying the derived inverse spectral solution allows for determining thermal conductivity throughout the soil‐water system across depths ranging from 0.1 to 1.2 m. As a result, this research demonstrates the feasibility and practicality of assessing the thermal conductivity of the soil layer in conjunction with heat flux and temperature gradients through spectral analysis.

Microplastics attenuation from surface water to drinking water: Impact of treatment and managed aquifer recharge – and identification uncertainties

River water can be used to recharge aquifers exploited for drinking water production. Several recent studies reported microplastics (MPs) in river water, and therefore, the potential contamination of groundwater by MPs is a growing concern among stakeholders and citizens. In this research, we investigate the fate of MPs (> 20 μm) along six different stages of a major Managed Aquifer Recharge (MAR)-water supply system in Switzerland. About 20 l of water were filtered using steel meshes at each location in triplicates. In the laboratory, MPs deposited on the anodisc filters were identified using Focal Plane Array (FPA) micro-Fourier-Transform-InfraRed (μFTIR) spectroscopy. The obtained hyperspectral data were processed using the imaging software Microplastics Finder for MPs identification and classification. Our results revealed a 20-fold decrease in MPs concentration from the Rhine River bed water (112 ± 27.4 MPs/l) to after the coagulation, flocculation and sedimentation (5.5 ± 2.2 MPs/l), a further 3-fold decrease to after the sand-filtration system (1.8 ± 0.9 MPs/l), corresponding to an overall removal efficiency of 98.4 %. The MPs concentrations remained low following MAR (2.7 ± 0.7 MPs/l) through a Quaternary gravel aquifer. Activated carbon filters did not substantially further reduce MPs concentrations. The percentage of fragments (≈95 %) prevailed over fibers (≈5 %) at all locations, with fibers being longer and more abundant in the river water. Overall, this study demonstrates the effectiveness of the treatment systems to remove MPs larger than 20 μm. Finally, we calculated an uncertainty in MPs concentrations of one order of magnitude depending on the user-defined parameters inside the MPs identification and classification model. The Quality Assurance/Quality Control approach followed during laboratory analysis highlighted an accumulation of surrogate particles at the edges of the disc, which would have an impact for MPs number upscaling.

The Influence of Water Temperature on the Hydrogeochemical Composition of Groundwater during Water Extraction and Reinjection with Geothermal Heat

This study presents a simulation of potential changes in groundwater in three wells within a Quaternary gravel aquifer in the city of Ljubljana when groundwater cooled by about 4 °C is reinjected into it. The research focuses on the mass transport of calcite in the vicinity of boreholes. According to our results, the impact of the changes in the geochemical composition of the water is relatively small (around 1%). Although the waters are approximately in equilibrium, calcite may be dissolved and sometimes precipitated within the aquifer when cooled water is reinjected into it. The amounts of precipitated calcite always decrease with decreasing temperatures of the reinjected water, which can lead to calcite dissolution if the temperature difference is large enough and the water is only slightly oversaturated. This novel finding is significant since previously published studies have mostly focused on understanding the scaling (precipitation) of calcite and not its dissolution. The mass transfer of calcite is relatively low, but in a scenario of long-term pumping for several years, such low values could lead to a dissolved or precipitated mass of several hundreds of kilograms of calcite per year (at a pumping rate of 46 L/s).

Using python libraries and k-Nearest neighbors algorithms to delineate syn-sedimentary faults in sedimentary porous media

This paper introduces a methodology based on Python libraries and machine learning k-Nearest Neighbors (KNN) algorithms to create an interactive 3D HTML model (3D_Vertical_Sections_Faults_LRD.html) that combines 2D grain-size KNN-prediction vertical maps (vertical sections) from which syn-sedimentary faults and other features in sedimentary porous media can be delineated. The model can be visualized and handled with conventional web browsers. The grain-size physical parameter is measurable, constant over instrumental time, handleable mathematically, and its range can be associated to lithological classes. Grain-size input data comes from a public database of 433 boreholes in the Llobregat River Delta (LRD) in NE Spain. Four lithological classes were defined: Pre-Quaternary basement, and Quaternary gravel, sand, and clay–silt. Using a new KNN-prediction algorithm, seven NW–SE (transversal) and three SW–NE (longitudinal) vertical sections were created following the orientation of faults identified in surface and detected in reflection seismic geophysical surveys. For exploratory K values in the 1–75 range were used. K around 25 provides the general and smoothy shape of the basement top surface, whereas K = 1 is a optimal value to represent the heterogeneity of the LRD at short distance. Using a new KNN-prediction confidence algorithm inspired in the Similarity Ratio algorithm for machine-learning KNN, the vertical sections overall confidence was evaluated as satisfactory. A general decreasing confidence trend according to the decreasing data density with depth and from inland to seaward was found. The vertical sections created with K = 1 show horizontal interruptions (displacements or vertical steps) in the basement continuity and in the Quaternary coarse bodies (gravel and sand) attributable to the action of Quaternary active faults. These faults have been linked or correlated with well-known active faults in the area related in much cases with the Valencia Trough opening. Moreover, several faults detected in surface and other identified in this paper by the first time have been revealed as fault zones made of fault branches with different steps in an echelon-like arrangement. Faulting seems to be more evident in the Pleistocene Lower Detrital Complex and much less active or inactive in the Holocene Upper Detrital Complex. Syn-tectonic gravel channels faulty controlled, progradation of gravel lobes, and lateral migration of channel bars were also observed. At its current development stage, this methodology could also be applied to other geological environments, making the due minor modifications of the code, and is especially suitable to reduce the high (usually unmeasurable) uncertainty associated to the qualitative geological data used in more complex numerical tools aimed at modelling a lot of geological resources (groundwater, minerals, geothermal, petroleum) or different Earth phenomena.

A K-Nearest Neighbors Algorithm in Python for Visualizing the 3D Stratigraphic Architecture of the Llobregat River Delta in NE Spain

The k-nearest neighbors (KNN) algorithm is a non-parametric supervised machine learning classifier; which uses proximity and similarity to make classifications or predictions about the grouping of an individual data point. This ability makes the KNN algorithm ideal for classifying datasets of geological variables and parameters prior to 3D visualization. This paper introduces a machine learning KNN algorithm and Python libraries for visualizing the 3D stratigraphic architecture of sedimentary porous media in the Quaternary onshore Llobregat River Delta (LRD) in northeastern Spain. A first HTML model showed a consecutive 5 m-equispaced set of horizontal sections of the granulometry classes created with the KNN algorithm from 0 to 120 m below sea level in the onshore LRD. A second HTML model showed the 3D mapping of the main Quaternary gravel and coarse sand sedimentary bodies (lithosomes) and the basement (Pliocene and older rocks) top surface created with Python libraries. These results reproduce well the complex sedimentary structure of the LRD reported in recent scientific publications and proves the suitability of the KNN algorithm and Python libraries for visualizing the 3D stratigraphic structure of sedimentary porous media, which is a crucial stage in making decisions in different environmental and economic geology disciplines.

Origin of Late Quaternary Gravel and Drainage Basin Expansion in the Northern Chinese Tian Shan: Insights From Sediment Provenance Analyses

AbstractThe source‐to‐sink relationship between a sedimentary basin and its adjacent mountain range is vital for understanding the genesis of piedmont coarse‐grained sediments and the evolution of mountain topography. By integrating zircon U‐Pb dating and heavy mineral assemblage analyses on 15 samples, this work focuses on the change of the provenance with time in the Urumqi River Neogene‐Pleistocene continental sequence in the northern Chinese Tian Shan foreland, which has been chronologically constrained to range from ∼6.8 to ∼0.55 Ma. The results of the integrated provenance analyses reveal two shifts in provenance during the periods of 4.6–2.5 and 0.9–0.55 Ma, yielding new zircon U‐Pb age signals from the glacier‐covered headwaters of the Urumqi River. These two identified provenance adjustments are causally related to enhanced glacial erosion in the high mountain. We propose that enhanced glacial erosion could have caused southward expansion of the Urumqi River drainage basin, increased production of coarse‐grained materials with new zircon U‐Pb age signals, and finally accumulation of piedmont alluvial gravel. The observed topographic and sedimentary responses to enhanced glaciation could have been common phenomena during the late Quaternary in alpine areas, where a large number of alluvial fans are widely distributed like aprons along the mountain front, as seen in the piedmonts of the Tian Shan in the arid interior of Asia.

Early Pleistocene complex cut-and-fill sequences in the Alps

Cut-and-fill sequences are the result of climatically or tectonically induced alternating aggradation and incision phases of a fluvial system. A recently established cosmogenic nuclide chronology of the Cover Gravels (Deckenschotter in German) in the northern Alpine Foreland, which are the oldest Quaternary glaciofluvial gravels and comprise evidence of early Pleistocene glaciations, suggests a cut-and-fill build-up. This suggested cut-and-fill architecture challenges the morphostratigraphy. The Deckenschotter deposits represent a suitable archive for reconstructing drainage patterns, base level changes, and the landscape evolution of the northern Alpine Foreland during the early Pleistocene. In this study, we focused on the highest morphostratigraphic Deckenschotter sites: three at Irchel and one in the area around Lake Constance. Sediment analyses were performed to determine their provenance and depositional environments. The geochronology was established using isochron-burial dating. The results indicate that the sediments were transported from the Central and eastern Central Alps, as well as from the Molasse, to the foreland and deposited in a proximal glaciofluvial environment. Based on these findings, we propose that the Deckenschotter are cut-and-fill sequences that accumulated in three stages during the early Pleistocene at ca. 2.5 Ma, ca. 1.5 Ma, and ca. 1 Ma. The presence of a cut-and-fill system implies that the regional base level was relatively constant during the early Pleistocene. In addition, the ca. 2.5 Ma glaciofluvial gravels document the first evidence of glaciers in the northern Alpine Foreland. This timing is synchronous with the onset of Quaternary glaciation in the northern hemisphere at ca. 2.7 Ma.

Coherence between sunlight quantum and soil water content in the shallow Quaternary gravel layer: Evidence of the spectral analysis

Due to the heterogeneity and nonlinear process in the unsaturated soil zone, it is challenging to represent the analytical mechanism and actual in-situ water content in the soil layer. With this in mind, this study provides a novel approach to discern the water content in the shallow Quaternary gravel layer at various depths using temporal sunlight and air temperature observation. It demonstrates significant components in spectral density to evaluate the crucial importance concerning the time-dependent soil water content, sunlight quantum, and air temperature. It shows that the soil water content at 10 cm depth can distinguish the fluctuated manner of light quantum at the time lag of about 6.6 and 5.1 h for diurnal and semidiurnal processes, respectively. The time progress of soil water contents at 30 cm depth is less relevant to 10 cm depth, but the phase at 60 and 120 cm depth is nearly in phase. Due to heterogeneity in the shallow layer, the temporal changes of soil water content below 10 cm depth have varying coherence degrees. Thus, using spectral analysis, practically estimating the coherence and time lag between light quantum, air temperature, and soil water content becomes feasible and achievable.

VERIFICATION OF THE BEARING CAPACITY OF PILES

The location of the buses in the basement of the new bus station in Bratislava, supplemented by two further parking floors below, shifted the foundation joint of the new bus station to a depth of approximately 14 m. The maneuvering space for the buses required unusually large distances between the supporting columns. In extreme cases, it was necessary to transfer a vertical load of more than 30,000 kN from the column to the subsoil. Only a relatively thin layer of Quaternary gravel remained between the footing bottom and the Neogene soils. The whole area was designed to be based on deep foundations. As this was a construction of the 3rd geotechnical category, it was necessary to verify the bearing capacity and quality of the piles. The applied test methods (especially the dynamic load tests) confirmed the correct design and implementation of piles.

Groundwater Characterization and Salinity Intrusion Studies using Electrical Resistivity Survey (ERS)-Winder, Balochistan, Pakistan

The groundwater resources have always been explored for its utilization in domestic and agriculture purposes. In this study, Winder area in Balochistan which is along the coast of Offshore Indus Basin has been explored using electrical resistivity method for deeper understanding of hydrogeological and hydrogeophysical conditions. Schlumberger electrode arrays have been used to acquire vertical electrical sounding data for 23 different sites in this area. The field data were calibrated with theoretical curves during processing using software with graphical interface. The true resistivities, depths, thicknesses, aquifer attributes, soil type and groundwater quality has been extracted from the processed data. Pseudo-sections and geo-electrical lithology sections have been generated for lateral distribution of hydrogeological settings. Furthermore, Dar-zarrouk parameters calculations have been made and 3D surfaces generated at 30m and 60 m depth for transverse resistance (T), longitudinal conductance (S) and anisotropy (λ) plotted for resistivity distribution and coastal salinity intrusion analysis. The soundings results depict five layers mainly composed of silty sand, sandy clay, sand, and sandy gravel and the depth ranges from 0-110m. The interpretation illustrates that freshwater unconfined aquifer are present in the quaternary sand and sandy gravel deposits. The water table is at shallow depth along the river and deeper in northeast and away from Winder river. The resistivity ranges 29-1091 Ωm in layer-3 interpreted as saturated zone. The approximate range of water table is 19-30 m. The higher value of T greater than 10000 shows fresh water and low value 8200 for salinity intrusion in southwest toward sea.

Sedimentology of Tertiary and Quaternary Gravel and Sand Beds of Dhalbhumgarh-Chakuliya-Baharagora Area, East Singhbhum District, India

Sedimentology of Tertiary and Quaternary Gravel and Sand Beds of Dhalbhumgarh-Chakuliya-Baharagora Area, East Singhbhum District, India

GPR survey to reveal a possible tectonic tilt of the Brežice Sava River Terrace in the Krško Basin

It has been supposed that the Brežice Sava River Terrace (BSRT) is tectonically disturbed near the town of Brežice and tilted to the north. To confirm this tectonically induced tilt in a quantitative sense, low-frequency Ground Penetration Radar (GPR) was applied. A total of eight GPR profiles were recorded across the BSRT providing information of the lower boundary of the terrace, which consists of loose to poorly cemented Quaternary gravel, while its Tertiary basement consists of poorly cemented carbonaceous silt (marl). The premise of the study was the assumption that this lithological boundary could be detected by the GPR method. In addition to the upper surface of the BSRT being tilted to the north by 0.18°, GPR profiles also showed a 0.04° difference in the tilt between the upper surface of the terrace and its lower boundary with the basement, which we assigned to the sin-sedimentary tilt. Upon this information, a cumulative tectonically induced dip of the BSRT lower boundary was defined at 0.22

Late Quaternary thrusting in the southern margin of the Chaiwopu Basin, northern Chinese Tian Shan foreland

AbstractThrusting and the associated folding are crucial geological processes accommodating the crustal shortening in a foreland setting. This work focuses on the late Quaternary thrusting of the Banfanggou fault (BF) in the southern Chaiwopu Basin, northern Chinese Tian Shan foreland. The outcrops at the Urumqi River in the western part of the southern margin of the basin show that the BF, dipping south with angle of 60–80 °, has thrust the Neogene mudstone onto the Quaternary gravels and has displaced the terrace surfaces. In contrast, the eastern segment of the BF exists as a blind thrust fault. By using the geomorphic surface (river terrace and alluvial fan) as the reference, the average rate of vertical slip on the western segment of the BF over the past ~12 ka is estimated to ~1.7 mm/year, and the estimated rate at the eastern segment of the fault is ~1.0–1.3 mm/year. Despite of the uncertainties of the rates deriving from the vertical offsets and the geomorphic ages, the resultant vertical slip rates might imply relatively high seismic risk in the southern Chaiwopu Basin.

Active faulting and seismic hazard in the Outer Western Carpathians (Polish Galicia): Evidence from fractured Quaternary gravels

This report opens a new window on Quaternary tectonics of the Outer Western Carpathians. We discuss results of fractured clasts analysis in Quaternary fluvial gravels within a 4.500 km2 large area comprising a part of the Outer Carpathians including Nowy Sącz Intramontane Basin (NSIB) as well as in the innermost part of the Carpathian Foredeep. Quaternary gravels bearing fractured clasts are widespread within the area, we observed them in 180 exposures. In the Carpathian Foredeep and in the Outer Carpathians excluding the NSIB, the exposures of gravels bearing fractured clasts are located largely close to (<2 km) all major overthrusts and close to (<0.75 km) the cross-fold faults of the Skawa River Fault System (SRFS). The clast-cutting fractures are mostly joints attesting to widespread Quaternary tectonic activity of the faults. Moreover, the density of occurrence of gravels bearing fractured clasts is considerably higher within the NSIB than in other parts of the study area. Furthermore, our results shed new light on the seismic hazard in the study area. In our interpretation, the clast-cutting fractures are damage resulting from coseismic rupturing of underlying bedrock faults or from regional seismic shaking. We conclude that in the study area the seismic hazard posed by natural seismicity can matter only in case of planning there the erection of critical structures like nuclear power plants, nuclear waste repositories or gas storage facilities. On the other hand, we infer that the appreciable seismic hazard is near the cross-fold faults of the SRFS, due to the location of Świnna Poręba Artificial Lake there, which can lead to triggering significant seismicity in the area. Furthermore, we suggest that fractured clasts can serve worldwide as providers of information on paleoseismicity and can be useful for mapping blind faults.

Enhanced Characterization of Water Resource Potential in Zaghouan Region, Northeast Tunisia

This study presents a range of approaches to achieve enhanced characterization of the Zaghouan aquifer system (northeastern Tunisia). Existing water borehole data were analyzed to identify the different reservoir formations, while satellite imagery is analyzed to determinate the superficial lineaments affecting these formations. To define the deep structures determining the geometry of the Zaghouan aquifer system, lithostratigraphic correlations were constructed and analyzed supported by both quantitative and qualitative assessment of gravity measurements. The available lithological columns and their corresponding well logs reveal different carbonate and detritic reservoirs. The carbonate reservoirs consist of Jurassic, Cretaceous and Eocene limestones, whereas the detritic ones are composed of Oligo–Miocene sandstones and Plio-Quaternary to Quaternary sands and gravels. The structural map obtained from processing the satellite imagery confirms several lineaments drawn on the geological map, such as the Zaghouan fault, but also reveals new ones hitherto unrecognized. The intersections of the detected lineaments explain the occurrence of many springs in the area offering potentially favorable opportunities for accessing water resources in fractured aquifers. Analysis of lithostratigraphic correlations shows notable variations in the thickness, depth and composition of reservoir formations. Gravity data interpretation gives more precision by highlighting buried structures and discontinuities with different directions and depths. The delineated tectonic features demonstrate an aquifer system compartmentalized in raised and subsided blocks. The raised compartments may constitute continental divide areas and preferential aquifer recharge zones, while the sunken ones contain a multilayer aquifer composed of Quaternary and Pliocene reservoirs overlying multiple permeable layers, Tertiary and/or Mesozoic in age.

GEOLOGICAL ASSISTED ON WATER RESOURCES PLANNING IN MOUNTAINOUS CATCHMENTS IN KUNDASANG, SABAH, MALAYSIA

Based on geological mapping and geohydrologic data, water resources planning in mountainous catchment areas in Kundasang are outlined. The area is underlain by thick Paleogene clastic sediment and old Quaternary gravels. These rock units are carved by numerous lineaments with complex structural styles developed during series of regional Tertiary tectonic activities. The tectonic complexities reduced the physical and mechanical properties of the rock units and produced intensive displacements and discontinuities among the strata, resulting in high degree of weathering process and instability. The weathered materials are unstable and may cause subsidence and sliding induced by high pore pressure subjected by both shallow and deep hydrodynamic processes. Evaluation of 60 boreholes data in the study area reveals that the depth of the groundwater table ranges from 1.90 m (6 feet) to 11.20 m (35 feet) deep. The groundwater level in the study area fluctuates even within a short period of any instability of climatic change. The Quaternary sand and gravel layers with variable thickness defined the major shallow aquifers within the underlying weathered materials while the highly fractured sedimentary rocks defined the major deep aquifers. Most of the aquifers within the top unconsolidated weathered clastic material are under unconfined condition. The sedimentary formations are coarse-grained clastic materials generally contain fractured porosity and exhibit higher permeability. However, below subsurface, much of the groundwater is partially confined. Movements of groundwater are sufficiently restricted area to cause slightly different in head depth zones during periods of heavy pumping. During periods of less draught, the various groundwater levels will be recovered to their respective original level. This condition resulted from discontinuous nature of sediments where zones of permeable sand and gravel are layered between less permeable beds of silt and clay. Aquifer characterization and geological data are given to assist the local agencies on the water resources planning of the study area.

The Middle Pleistocene fluvial sequence at Uichteritz, central Germany: Chronological framework, paleoenvironmental history and early human presence during MIS 11

The site of Uichteritz (Saxony-Anhalt, Germany) is a Quaternary gravel quarry hosting several Middle-Pleistocene fluvial units of the Saale River. This fluvial archive contains detailed information on (1) the timing of Middle Pleistocene fluvial aggradation and erosion periods in the region, (2) the driving forces for those alternations, as well as (3) early human presence indicated by the presence of Lower Paleolithic stone artefacts. Here we establish a luminescence-based numerical chronology at Uichteritz. Additionally, geophysical, sedimentological and micromorphological analyses were applied to obtain information on depositional and post-depositional processes of the fluvial sequence.Our results point to several fluvial aggradation periods between ca. 420 and 180 ka. A first fluvial unit was deposited during the late Elsterian period, followed by formation of a Luvisol during MIS 11 and its fluvial reworking at the transition from MIS 11 to MIS 10 and/or during early MIS 10. These MIS 10/11 deposits, with an age of about 400 ka, also contain reworked Lower Paleolithic stone artefacts that document the initial appearance of humans in northwestern central Europe during MIS 11. After a period of fluvial incision during MIS 10, which was accompanied by a change in the course of the Saale River, several stacked fluvial sequences of the Saalian Main Terrace (SMT) formed between MIS 8 and MIS 6, mainly during cold climatic periods. Our age estimates confirm the correlation of the Elsterian ice advances with MIS 12, and the Saalian ice advances with later MIS 6.

Liquefaction potential of sands at the Krško-Brežice field, Slovenia

The Krsko-Brežice field is one of the most seismically active areas in Slovenia. The most damaging recorded earthquake with an intensity of VIII (EMS) occurred on 29th January 1917. It caused damage and claimed two lives. In the last 100 years, 9 earthquakes with intensity higher than VI (EMS) have been recorded. At the investigated area, a top layer up to 5 m thick, consisting of recent deposit of very loose silts and sands (ML, SM, SP), covers the medium dense to dense Quaternary gravel, beneath which there are over-consolidated, uncemented Miocene silts and marls. The top layer could be prone to liquefaction, as reported for the close surroundings of Brežice, where the liquefaction phenomenon was observed during the Zagreb earthquake in 1880 and during the Kupa Valley earthquake in 1909. The paper presents the results of laboratory index tests, cyclic simple shear tests and field investigations (SPT, CPT, (S)DMT, vs measurements), which were carried out to assess the liquefaction potential of the top layer at the location of the Brežice Hydroelectric Power Plant (HPP). All results show that the top layer is prone to liquefaction for an earthquake with a 475 year return period. Cyclic simple shear test results show that the liquefaction potential of horizontal ground for an earthquake with a 475 year return period can be reduced by the densification of the top layer to at least 95% of maximum Proctor density.

Remote sensing, GIS and chemical analysis for assessment of environmental impacts on rising of groundwater around Kima Company, Aswan, Egypt

BackgroundKima company is located east of the river Nile, 2.5 km south of Aswan City. The Quaternary sands and gravels represent the main groundwater aquifer in the area. It is mainly recharged from the river Nile seepage between the high and the old Aswan Dams. Some water seepage comes from the fish hatchery canal close to the area. The objective is to study the temporal-spatial development of the drainage ponds resulting from the rise of the groundwater level in line with the agricultural and urban development in and around the Kima plant area using chemical analysis and advanced technology (remote sensing and GIS techniques).ResultsMany wells were drilled and used to pump the groundwater in and south of the area, from which 15 wells that were used to feed Aswan city by drinking water were stopped since 2009. As result, the groundwater level rises and most of the wells of Kima company flooded. The groundwater quality deteriorated and some environmental changes in the surrounding area were detected. Monitoring and analysis of these changes are studied using remote sensing and GIS techniques. The results show an increase in both the surface water bodies (ponds) and urban areas.ConclusionsSince 2009, 15 productive drinking water wells were ceased in the study area. It is the main reason which caused more rising of the groundwater level accompanied by increasing of its salinity. The study detected and calculated the area influenced by the groundwater seepage, urbanization, and the agricultural reclamation areas. The successive changes in these parameters throughout the period 2007–2017 are calculated. Rising groundwater levels are expected to be a chronic problem and will likely be a major issue for residential areas of Aswan city.

Hydrochemical Characteristics and Formation of the Madeng Hot Spring in Yunnan, China

The Madeng hot spring emerges in the central river valley in the northeastern Lanping Basin in Jianchuan county of Yunnan Province in China. Quaternary sand and gravel occur in the valley which is underlain by the red beds consisting of sandstone and mudstone. The temperature of the hot spring is 42.1°C. The spring water has a pH value of 6.41, TDS of 3.98 g/L, F contents of 3.08 mg/L, and H2SiO3 of 35.6 mg/L. The hot water is of SO4•Cl-Na•Ca type. There is a slight hydrogen sulfide odor in the spring water. Stable hydrogen and oxygen isotopes indicate that the hot water is of meteoric origin. It is estimated that the elevation of the recharge area of the hot spring is approximately 3800 m, the age of the hot water is some 140 years, the temperature of the geothermal reservoir is 75°C–80°C, the mixture ratio of cold water is approximately 80%, and the circulation depth of the thermal groundwater is 1870 m. After receiving recharge from infiltration of precipitation in the mountainous recharge areas, the groundwater undergoes a deep circulation, obtains heat from the heat flow, flows upward along the fractured zone, and emerges as an upflow spring through the Quaternary sand and gravel in the central low-lying river valley.