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Groundwater flow in fractured rocks is modeled using a coupled model based on the domain decomposition method. In the model, the fractured porous medium is divided into two non-overlapping sub-domains. One is the rock matrix, in which the medium is described using a continuum model. The other consists of deep fractures and fissure zones, where the medium is described using a discrete fracture network (DFN) model. The two models are coupled through the continuity of the hydraulic heads and fluxes on the common boundaries. The coupled model is used to simulate groundwater flow in a hydropower station. The results show that the model simulates groundwater levels that are in agreement with the measured groundwater levels. Furthermore, the model’s parameters relating to deep fractures and fissure zones are verified by comparing three different models (the continuum model, coupled model, and DFN model). The results show that the coupled model can capture and duplicate the hydrogeological conditions in the study domain, whereas the continuum model overestimates and the DFN model underestimates the measured hydraulic heads. A sensitivity analysis shows that fracture aperture has a considerable effect on the groundwater level. So, when the fracture aperture is large, the coupled model or DFN model is more appropriate than the continuum model in the fracture domain.

The main ions were measured seasonally during two years at 13 sampling stations in the Salado River and its main tributaries. The importance of each ion was assessed by standard methods used to examine ionic composition and by multivariate methods. The K-means clustering and Principal Component Analysis were applied to the percentages of the major ions. The concentration of the major cations are in the order Na+ > Mg2+ > Ca2+ > K+ and the major anions, Cl− > SO 4 2−  > HCO 3 −  > CO 3 2− , and the salinity was high (mean TDS 2,691 mg l−1) due to sodium chloride. Using the proportions of the ions was possible to identify seven types of water within the basin related to discharges of different river sub-catchments and from endorheic catchments (in a sand dune region) actually connected with the basin by canals. The chemical composition of the basin is consequence of surface waters receiving salts from groundwater, evaporation and weathering of Post-Pampeano materials, and of anthropogenic impact by diversion between subcatchments for flood control. These results allowed us to test the marked effects on the ionic balance of basin at the base of a diversion management from endorheic catchments characterized by high salinity waters.

Landslide activity is largely controlled by changes in soil properties, particularly soil moisture and the corresponding changes in pore pressure within the vadose zone. While knowledge of changes in soil conditions is of utmost importance for the prediction of landslides, it is difficult to obtain reliable information on the field scale. A possibility of filling that information gap is the monitoring of changes in soil properties by time-lapse electromagnetic induction (EMI) data. Given the relative stability of soil properties, changes in apparent electric conductivity (ECa) are mainly related to changes in soil water content and its mineralization. Thus, we use time-lapse ECa data over a nine-month period from different investigation depths (0.75, 1.5, 3, and 6 m) to separate areas with different temporal behavior of soil properties. However, working with time-lapse EMI data raised the comparability problem since the recoded ECa is also affected by several day-specific survey conditions (e.g., instrument temperature, operator). Consequently, the reproducibility of accurate ECa measurements is difficult due to potential dynamic shifts which hinders a direct comparing. We introduce in this study a straightforward method for comparability of ECa values from different time steps by normalization of data ranges assuming that the majority of shifts of measured data originate from field calibration. We identify the intensity of spatial changes by means of the standard deviation (SD) as an indication for the intensity of soil properties variability. To obtain the temporal changes and its progression over time, we separate the dynamic signal from the background. A two-layer system could be identified: one shallow more dynamic layer with an east–west-oriented structure and a deeper, more stationary layer with a north–south-oriented structure. The ECa dynamics of the shallow layer is related to the altitude (R 2 = 0.84) while the deeper dynamics follow a different regime. The decreasing of ECa dynamics with depth was consistent with the decreasing of SWC dynamics observed by previous studies.

Recognizing soil as a vital resource for food production and animal habitat, this study employed a comprehensive, nationwide erosion assessment in Bangladesh using the Revised Universal Soil Loss Equation (RUSLE) model. Rainfall, soil data, the Digital Elevation Model (DEM), Landsat 8 imagery, and land use and land cover (LULC) maps were employed as inputs for the prediction of potential soil erosion. Utilizing the zonal statistics tool within a geographic information system (GIS) platform, the study area's most erosion-vulnerable zones were subsequently identified and mapped. These zones were designated as 'erosion hotspots' (EHs) with demonstrably clear connections to river basins and networks. Analysis revealed an annual average erosion rate of 1.3 t ha−1 yr−1, resulting in an alarming loss of 17.68 million tons of topsoil annually. Notably, four distinct EHs were identified within the study area. The southeast region, due to its specific topography and climate, was found to be highly susceptible to erosion. Within this region, 2.22% (2995.93 km2) experience erosion exceeding 10.0 t ha−1 yr−1. RUSLE-based results were validated by comparison with outputs from the Global Soil Erosion Modeling Platform (GloSEM) and Google Earth imagery. In addition, the model's performance was evaluated using the receiver operating characteristic (ROC) curve and area under the ROC curve (AUC). The high AUC value of 0.94 achieved in this study reinforces the accuracy and confidence of the soil erosion estimations.

The mining activity in Peru is of long standing and its existence begins with the times and cultures pre Incas, Inca, colonial and the own Republic. This is due to the existence of deposits and important mineral resources distributed throughout the Peruvian territory. This paper reports a study focusing sediment profiles (LKS-1, LKS-2 and LKS-3) and water samples collected in Ramis River that is located in Ananea District, Puno Department, in southern Peru at the northern section of Titicaca slope. The CF:CS 210Pb chronological model allowed determine sedimentation rates useful for evaluating the history of the heavy metals contamination over the past 150 years in that mountainous area of the Peruvian Altiplano. The maximum concentration of As, Cr, Cu and Zn was, respectively, 400, 93, 93 and 20 ppm (LKS-1); 120, 95, 98 and 20 ppm (LKS-2); 98, 98, 87 and 40 ppm (LKS-3). Two linear sedimentation rates were identified in each profile along Ramis River: 0.14 and 0.15 cm/year (LKS-1); 0.33 and 0.21 cm/year (LKS-2); 0.31 and 0.24 cm/year (LKS-3). The respective deposition times were: LKS-1 = 76 and 177 years; LKS-2 = 85 and 130 years; LKS-3 = 86 and 144 years. Possible events related to the different rates would be the degradation of the native forest by anthropic actions, characterized by the activities of overturning and burning to carry out forest plantations, as well active processes taking place in the region like the urban growth.

The current regulatory requirement for cover soils in landfills and surface impoundments is that the soils attain, upon compaction, a very low hydraulic conductivity of 10−7 cm/s or less. Although the influence of the interaction between waste chemicals and clay soil on waste migration has been extensively studied, attempts to incorporate as design components the effects of sulfidic (sulfide-bearing) clays on the integrity of clay caps have largely been ignored. These influences may include increasing the permeability of the cover to percolating moisture, enhancing erosion of clay covers, and killing of vegetation on downslopes of the cover. Consequently, it is suggested that clay cap designers test the acid-generating capabilities of potential clay cap materials before exploiting these earth formations. This can be done by incubating a sample of the candidate capping material (with pH > 3.5) under moist aerobic conditions (field capacity) at room temperature. The soil will be said to contain sulfidic materials if it shows a drop in pH (1 ∶ 1 by weight in water) of 0.5 or more units to a pH value of 4.0 or less within eight weeks. Decisions should then be made as to whether the soil should be avoided or used with amendments to the cap design.

The increasing human engineering activities and frequent extreme weather events have caused extensive reactivation of ancient landslides, which are widely developed in the east margin of Tibetan Plateau. The Shangyaogou landslide, as a typical ancient landslide example in this area, was investigated to reveal the reactivation characteristics, and its stability was calculated under the continuous rainfall condition with the intensity 30 mm/day using the finite element software Geo-Studio. The whole movement process and hazard prediction under the different triggering conditions were simulated using the numerical software DAN3D. The study results showed that: (1) under the joint influence of Mw 7.9 Wenchuan earthquake, toe erosion and intensive rainfall, multi-stage deformations occurred to the front part of the Shangyaogou landslide in multiple periods and also indicated a significant potential instability; (2) under the continuous rainfall condition, when the single effective total infiltration reached about 65 mm, the reactivation part will become unstable. While the single effective total infiltration reached about 120 mm, both reactivation part and posterior part became instability; (3) the maximum run-out distance of the reactivation part was calculated to be 350 m, and the forefront of the accumulation deposit would not reach the residential area; When both parts failed simultaneously, the maximum run-out distance was calculated to be 550 m by considering the thickness and dynamic energy of the accumulation deposits, and the vulnerable elements inside the fan area with radius of 150 m would be severely threatened; (4) abundant earthquake-triggered landslides have been developing in history or in recent years in the eastern margin of Tibetan Plateau. Some of them have been partly reactivated due to the increasing human engineering activities and extreme rainfall events, and they have a potential for further deformation and failure. The presented study methods can provide guidance for local disaster prevention and mitigation, and can be used as a reference for the hazard prediction of the similar ancient landslides which have been reactivated.