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Groundwater pollution from subsurface leaching of eroded soil, pesticides and fertilizers under agricultural fields are deteriorating the quality of groundwater. In this connection, this study aimed to prepare a groundwater vulnerability map using the DRASTIC (Depth to water table, net Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone media and hydraulic Conductivity) model to evaluate the soil erosion and groundwater quality relationship under soil erosion prone areas of the Panjkora river basin in the northern Pakistan. In this model, relative weights between 1 and 5 are assigned (5 being the most important) to D-R-A-S-T-I-C variables that may affect groundwater quality. According to the results, 72161.64 Hectares (ha) of the study area is low vulnerable to contamination, 144828.70 ha area is slightly moderate vulnerable, 239582.22 ha area is moderate vulnerable, 121769.37 ha area is high vulnerable, and 944.61 ha area is very high vulnerable to groundwater contamination. Groundwater samples from soil erosion hotspots were examined to establish a correlation between soil erosion and groundwater contamination. Total dissolved solids (TDS) and NO2 concentration in some areas were found to be higher than the World Health Organization (WHO) permissible limits. Soil erosion exhibited a positive correlation with groundwater contamination with correlation coefficient (r) of 0.89, root mean square difference (RMSD) of 2.24 and bias of 0.094. The DRASTIC model was validated through ROC AUC curve (score = 0.62). This study is a first attempt to evaluate the inherent groundwater vulnerability and sensitivity to pollution in this region with severely declining groundwater quality due to several unexplored reasons. [ABSTRACT FROM AUTHOR]

The high groundwater level coal mining areas have a long history of mining and are mainly located in east-central region of China. Subsidence caused by coal mining occur in several different periods. However, the subsidence change regularity in each periods remains unclear. This study aimed to reveal the subsidence change regularity in high groundwater level coal mining areas during different periods. The Juye coal mine, located in Heze City, Shandong Province, China, was selected for the study. Firstly, 55 Sentinel-1A radar satellite images from August 2018 to July 2020 were acquired for this research. The "two-track method" of D-InSAR technology was employed to process the images. Secondly, based on subsidence velocity of 1.7 mm/day, the subsidence process was divided into three periods: initial, active and weakening. Thirdly, elevation data of ground levelling points were used to check the accuracy of subsidence monitoring using Sentinel-1A data. At last, the subsidence change process in different periods was analyzed and the change regularity was summarized. The results are shown as follows: (1) the monitoring accuracy of different periods is high, and R2range from 0.961 to 0.983. (2) The subsidence characteristics are not obvious in initial period. The subsidence funnel begin to form and the mean maximum subsidence in center is greater than 1400 mm in active period. The subsidence velocity gradually decrease and eventually stabilize in weakening period. (3) Appearance of subsidence, development of subsidence funnels and formation of subsidence basins are spatial period characteristics of coal mining-induced subsidence. The results can provide an important basis for land conservation in mining areas. [ABSTRACT FROM AUTHOR]

Karst areas exhibit intricate geological attributes, and the geological and environmental issues caused by urban development cannot be ignored, especially the issue of karst surface collapses. In this study, we developed two analytical methods and analyzed the stability of the overburden stratum of 3D spherical karst caves with surface load, vacuum absorption erosion force, and groundwater table considerations. The first analytical method is based on the improved Terzaghi theory, while the second analytical method is based on the upper limit analysis. A case study was conducted in Wuhan, China. The results from both analytical methods indicated a potential susceptibility to collapse, suggesting the excellent accuracy of these two methods. The results were also compared with the numerical solutions from previous studies. Notably, the accuracy of the upper limit analysis was inversely proportional to the depth ratio, while the results obtained through the improved Terzaghi theory were consistent with those of the numerical solutions, particularly under conditions of relatively high depth ratios. This study examined various facets, including the development of karst caves, soil shear strength, groundwater table fluctuations, and boundary failure angles. Furthermore, we explored the effects of geometric and geotechnical parameters on the stability of karst caves. [ABSTRACT FROM AUTHOR]

Worldwide, the drainage of peatlands has turned these systems from CO2 sinks into sources. In the Netherlands, where ∼7 % of the land surface consists of peatlands, drained peat soils contribute >90 % and ∼3 % to the country's soil-derived and total CO2 emissions, respectively. Hence, the Dutch National Climate Agreement has set targets to cut these emissions. One potential mitigation measure is the application of subsurface water infiltration systems (WISs) consisting of subsurface pipes connected to ditchwater. WISs aim to raise the water table depth (WTD) in dry periods to limit peat oxidation while maintaining current land-use practices. Here, we used automated transparent chambers in 12 peat pasture plots across the Netherlands to measure CO2 fluxes at high frequency and assess (1) the relationship between WTD and CO2 emissions for Dutch peatlands and (2) the effectiveness of WISs in mitigating emissions. Net ecosystem carbon balances (NECBs) (up to 4 years per site, 2020–2023) averaged 3.77 and 2.66 tCO2-Cha-1yr-1 for control and WIS sites, respectively. The magnitude of NECBs and the slope of the WTD–NECB relationship fall within the range of observations of earlier studies in Europe, though they were notably lower than those based on campaign-wise, closed-chamber measurements. The relationship between annual exposed carbon (C; defined as the total amount of carbon within the soil above the average annual WTD) and NECB explained more variance than the WTD–NECB relationship. The magnitude of the NECB represented 1.0 % of the annual exposed C on average, with a maximum of 2.4 %. We found strong evidence for a reducing effect of WISs on CO2 emissions, reducing emissions by 2.1 (95 % confidence interval 1.2–3.0) tCO2-Cha-1yr-1 , and no evidence for an effect of WISs on the WTD–NECB and annual exposed carbon–NECB relationships. This means that relationships between either WTD or exposed carbon and NECB can be used to estimate the emission reduction for a given WIS-induced increase in WTD or exposed carbon. High year-to-year variation in NECBs calls for multi-year measurements and sufficient representative measurement years per site as demonstrated in this study with 35 site-year observations. [ABSTRACT FROM AUTHOR]

The application of hydrogeophysical techniques to delineating aquifers was conducted in De Aar, the eastern part of the Karoo region, Northern Cape, South Africa. Previously, recharge estimations in this region assumed a uniform aquifer type, overlooking the presence of diverse aquifer systems. This study identified both unconfined and confined aquifers to improve recharge potential assessments. Vertical electrical resistivity sounding (VES) and ground telluric methods were applied. Six VES stations and eleven profiles were measured using a 1D Wenner array configuration. The VES data, processed with IPI2win software, generated a 2D subsurface model. In contrast, the telluric data were analyzed using an automated algorithm to create a 2D profile. The electric potential difference curve was interpreted in comparison with lithological cross-sections. The VES results revealed three to four distinct layers of low-resistivity (0.9–8.1 Ωm), moderate-resistivity (22.4–125 Ωm), and high-resistivity (68–177 Ωm) values, indicating three lithological formations. The telluric data suggested that shallow groundwater boreholes were located in areas with groundwater levels above 50 m. These findings, which matched the lithological data, pointed to a double-layer aquifer system, suggesting that recharge estimates should be carried out to different aquifer layers. The study demonstrated how hydrogeophysical methods can effectively delineate aquifer systems and enhance the identification of recharge areas. [ABSTRACT FROM AUTHOR]

Seawater intrusion seriously threatens the quality of coastal groundwater, affecting nearly 40% of the world's population in coastal areas. A study was conducted in the Kamini watershed situated in the Udupi district of Karnataka to assess the groundwater quality and extent of seawater intrusion. During the pre-monsoon period, 57 groundwater and 3 surface water samples were analyzed to understand the impact of seawater on the groundwater and surface water. The analysis revealed that the groundwater in the study area is slightly alkaline. The weighted overlay analysis map indicated that 11% of the study area is unsuitable for drinking water due to the influence of seawater. The Piper plot analysis revealed that the groundwater is predominantly CaMgCl facies. The hydrogeochemical facies evolution diagram (HFED) showed that 62% of the groundwater is affected by seawater. The HFED and Piper plots also indicate that the surface water is also affected by seawater. These results are also supported by various molar ratios such as Cl− vs. Cl⁻/HCO3⁻, Cl⁻ vs. Na⁺/Cl⁻, Cl− vs. SO42−/Cl−, and Cl⁻/HCO3− vs. Mg2+/Ca2+, suggesting that the majority of the water sample has been affected by seawater. The saturation indices indicated that mineral dissolution has significantly contributed to groundwater salinization. The correlation between sulfate concentration and calcite and dolomite dissolution suggested the influence of seawater intrusion in the coastal aquifer. The process of reverse ion exchange mainly influences the groundwater chemistry according to chloroalkali indices. The total hazard index (THI) values of nitrate and fluoride exceeded limits, posing health risks to adults and children. Studies suggest that with time and space, seawater intrusion is increasing in some pockets of the study area, especially along the west coast. [ABSTRACT FROM AUTHOR]

Groundwater is one of the most important sources of freshwater, contributing significantly for drinking and other domestic activities around the world. However, its quality is deteriorating over time due to overexploitation and anthropogenic activities. Rib watershed is located in the Tana basin (Ethiopia), is intensively cultivated and urbanizing area. Therefore, this study attempted to assess groundwater vulnerability to pollution using the GIS-based Modified DRASTIC Model. The modified DRASTIC model was selected due to it incorporates both hydrogeological parameters and anthropogenic factors for assessment. The necessary data were collected from the field, and downloaded from websites and laboratory experiments (No3-). The results showed that more than 73.24% of the watershed is under medium to high vulnerability. Highly vulnerable areas of the watershed (22.48%) was confined to the Southern parts of the watershed (under built-up and cultivated areas). Based on single parameter sensitivity analysis, its vulnerability was highly influenced by aquifer media (24.1%), net recharge (21.75%), land use/land cover (15.1%), and depth of groundwater table (13.6%). The Modified drastic model was validated based on the observed data of nitrate concentration in groundwater. Based on the observed data of nitrate concentration, high-vulnerable areas were more contaminated than medium and low-vulnerable areas. The modified drastic index has a strong correlation with nitrate concentration with (r = 0.76) and (P < 0.043). Therefore, the result indicated that the area is vulnerable to contamination calling for appropriate groundwater management. Hence, this finding helps to plan and minimize future contamination of groundwater by considering its vulnerability before high-risk activities are allowed. [ABSTRACT FROM AUTHOR]

The Colorado River is a vital water source for the western United States, yet the river is governed by disjointed and outdated policies that have left water management fragmented and water quantities overallocated. Groundwater is an overlooked component of Colorado River Basin (CRB) water supplies, making it vulnerable to overuse from disparities in uncoordinated protective management strategies. In this study, we analyzed state level groundwater policies to reveal the diversity and efficacy of groundwater governance mechanisms. The existing groundwater management plans for each state throughout the basin are fragmented and limited in scope. We found that with policies only covering 22% of the basin, they do not provide adequate protection at the basin scale for the sustainable use of groundwater resources in the face of increasing demands, creating a positive feedback loop that reinforces the scarcity issue. We conclude that a comprehensive management plan that can fully address resource use throughout the CRB is necessary for the sustainable use of groundwater and its contribution to base flow in the Colorado River. We suggest that such a plan could be derived through an interstate compact like the Colorado River Compact that is used for surface water management. [ABSTRACT FROM AUTHOR]

In this study we evaluate the uranium and radon concentrations in groundwater from the Province of Safi. The samples were collected from 58 wells across five communes and analyzed using the LR-115 type II detector. Results indicate that uranium concentrations ranged from the Limit of Detection (LLD) to 3.73 µg/l, with a mean of 0.72 µg/l, well below the World Health Organization’s safe limit of 30 µg/l. Radon levels varied from LLD to 2.39 Bq/l, with an average of 0.60 Bq/l, also below the United States Environmental Protection Agency’s limit of 11 Bq/l. The estimated total annual effective dose due to uranium and radon ranged from 3.47 to 18.84 µSv/y, with an average of 7.54 µSv/y, which is significantly lower than the European Commission’s recommended limit of 100 µSv/y. This investigation represents the first study of uranium and radon levels in groundwater in the Province of Safi, providing valuable data for future research and public health. [ABSTRACT FROM AUTHOR]

As in most chalk river valleys in NW Europe, the sedimentary fill of the Somme valley is mainly composed of fluviogenic alkaline peat. The site of Morcourt exhibits a thick and well‐preserved fluvial sequence (10 m, including 6 m of peat). This sequence provides the framework for reconstructing fluvial and palaeoenvironmental dynamics from the end of the Upper Weichselian Pleniglacial (~20 000 cal. a BP) to the High Middle Ages (~700 cal. a BP). The palaeoenvironmental reconstruction is based on a high‐resolution stratigraphic study of 60 transect cores, 36 radiocarbon dates and sedimentological, geochemical, pollen and plant macrofossil analyses. There are three main phases in the development of the valley floor: (i) after the incision of the abandoned Pleniglacial braided river channels, a first generation of localized peat developed during the Bølling and the Allerød interstadial (<1 m thick); (ii) at the beginning of the Holocene, a peat formation phase began in the deepest parts of the valley and then spread over the valley floor by the end of the Middle Holocene (~4700 cal. a BP), with the limited runoff shifting to a small lateral channel; and (iii) at the transition to the Late Holocene, environmental changes, driven by the intensification of human activities and perhaps accentuated by climatic modifications, caused the incision of the peat system as a result of the formation of a channel. This channel drained the valley, and then mixed a detrital load into the peat. By the Low Middle Ages, the system had been altered to such an extent that the peat was completely covered by organic silty alluvium. The water table was lower, which definitively inhibited peat formation. The Morcourt sedimentary record (thickness and continuity) and the resumption of turfigenesis during the Late Holocene are remarkable in NW Europe, making this site a model of continuous morpho‐fluvial evolution since the Lateglacial. [ABSTRACT FROM AUTHOR]

As climate change shifts crop exposure to dry and wet extremes, a better understanding of factors governing crop response is needed. Recent studies identified shallow groundwater--groundwater within or near the crop rooting zone--as influential, yet existing evidence is largely based on theoretical crop model simulations, indirect or static groundwater data, or small-scale field studies. Here, we use observational satellite yield data and dynamic water table simulations from 1999 to 2018 to provide field-scale evidence for shallow groundwater effects on maize yields across the United States Corn Belt. We identify three lines of evidence supporting groundwater influence: 1) crop model simulations better match observed yields after improvements in groundwater representation; 2) machine learning analysis of observed yields and modeled groundwater levels reveals a subsidy zone between 1.1 and 2.5 m depths, with yield penalties at shallower depths and no effect at deeper depths; and 3) locations with groundwater typically in the subsidy zone display higher yield stability across time. We estimate an average 3.4% yield increase when groundwater levels are at optimum depth, and this effect roughly doubles in dry conditions. Groundwater yield subsidies occur ~35% of years on average across locations, with 75% of the region benefitting in at least 10% of years. Overall, we estimate that groundwater-yield interactions had a net monetary contribution of approximately $10 billion from 1999 to 2018. This study provides empirical evidence for region-wide groundwater yield impacts and further underlines the need for better quantification of groundwater levels and their dynamic responses to short- and long-term weather conditions. [ABSTRACT FROM AUTHOR]

The continued threat from climate change and human impacts on water resources demands high-resolution and continuous hydrological data accessibility for predicting trends and availability. This study proposes a novel threefold downscaling method based on machine learning (ML) which integrates: data normalization; interaction of hydrometeorological variables; and the application of a time series split for cross-validation that produces a high spatial resolution groundwater storage anomaly (GWSA) dataset from the Gravity Recovery and Climate Experiment (GRACE) and its successor mission, GRACE Follow-On (GRACE-FO). In the study, the relationship between the terrestrial water storage anomaly (TWSA) from GRACE and other land surface and hydrometeorological variables (e.g., vegetation coverage, land surface temperature, precipitation, and in situ groundwater level data) is leveraged to downscale the GWSA. The predicted downscaled GWSA datasets were tested using monthly in situ groundwater level observations, and the results showed that the model satisfactorily reproduced the spatial and temporal variations in the GWSA in the study area, with Nash-Sutcliffe efficiency (NSE) correlation coefficient values of 0.8674 (random forest) and 0.7909 (XGBoost), respectively. Evapotranspiration was the most influential predictor variable in the random forest model, whereas it was rainfall in the XGBoost model. In particular, the random forest model excelled in aligning closely with the observed groundwater storage patterns, as evidenced by its high positive correlations and lower error metrics (Mean Absolute Error (MAE) of 54.78 mm; R-squared (R²) of 0.8674). The downscaled 5 km GWSA data (based on random forest) showed a decreasing trend in storage associated with variability in the rainfall pattern. An increase in drought severity during El Niño lengthened the full recovery time of groundwater based on historical storage trends. Furthermore, the time lag between the occurrence of precipitation and recharge was likely controlled by the drought intensity and the spatial recharge characteristics of the aquifer. Projected increases in drought severity could further increase groundwater recovery times in response to droughts in a changing climate, resetting storage to a new tipping condition. Therefore, climate change adaptation strategies must recognise that less groundwater will be available to supplement the surface water supply during droughts. [ABSTRACT FROM AUTHOR]

Water-rich open-pit mines can have problems with large water inflows, slope reinforcement difficulties, and hazardous mining risks. The construction of a water cut-off curtain to control groundwater in the loose layer of an open-pit mine can effectively reduce the amount of water that must be pumped and eliminate the problem of flooding in the pit. However, the rise of the water level outside the curtain and changes in the geotechnical properties of the slope's material will affect the stability and safety of the pit's slope. A computational model was constructed and limit equilibrium and numerical simulation methods were used to determine the influence of a water cut-off curtain on the stability of the slope. Results show that with the the water cut-off curtain, the water level outside of the cut-off curtain in the loose layer of the open-pit mine continues to rise and the hydrostatic pressure and horizontal thrust of the slope body increases. As a result, the sliding force of the slope increases and the resisting force decreases, ultimately lessening the slope- stability coefficient (factor of safety) of the open pit. If the construction position of the curtain is moved outward, the stability coefficient of the slope will increase, assuming that the water level outside the curtain remains unchanged. Conversely, if the position of the curtain is moved toward the pit, the stability coefficient of the slope will decrease. The maximum shear stress on the slope increases as the water level outside the water curtain rises. The maximum shear stress is mainly concentrated at the toe of the slope of the first bench below the surface and at the interface between the curtain and the bottom of the loose material. If designed properly, the water curtain can control the water table in the slope's material, maintaining the stability of the slope. [ABSTRACT FROM AUTHOR]

The planning and management of water in the river basins require the identification of places where the quality of groundwater is being threatened. The risk of launching the accumulated pollutants present in the solid phase of the soil may be caused by both the changes in the pressure gradients in the aquifers and the changes in the hydrogeochemical balances. In the example of the Ner river valley, into which wastewater from the Łódź agglomeration has been discharged, the factors threatening the chemical status of groundwater were determined. This assessment was carried out based on the results of the determination of the hydrodynamic balance disturbances in the Upper Cretaceous formations, model studies of groundwater flow and hydrogeochemical studies conducted on the sorption complex of the Ner alluvium as well as the chemistry of the river water, alluvial water and groundwater. The results showed that the river water is heavily anthropogenically transformed. Model studies have shown that when the Ignacew -intake wells are pumped collectively, the inflow takes place through the Ner valley, where the hydrogeological window between the Quaternary and the Upper Cretaceous aquifers is found. The withdrawal by the Ignacew intakes may result in the reversal of piezometric pressures in the valley, which creates the possibility of the infiltration of polluted surface water into groundwater. Observations indicate the need to take into account the zones where surface water and water from the river alluvium are a real threat to the chemical status of the aquifers. These aspects are important when determining the protection zones and in renewable and disposal resource assessments of the Main Groundwater Reservoirs. [ABSTRACT FROM AUTHOR]

The paper describes the practical experience of a chemical stabilization of loess soil foundations of buildings and industrial facilities in Volgodonsk, using the single-component silicate solution method. It is pointed out that the low permeability of the compacted soil bed under the foundation bottom and excessive moisture content in the zone of capillary water rise above the groundwater table are insufficiently accounted for. The paper suggests considering the specific changes in density and moisture content between the foundation bottom and the ground water table of loess soils subjected to silicate solution treatment. Reliable values of soil density and moisture content are proposed to be obtained using geophysical (radioisotope) methods. The feasibility of a predictive assessment of the deformation of the surrounding buildings caused by changes in the hydrogeological conditions of the territory with soils subjected to stabilization is substantiated. [ABSTRACT FROM AUTHOR]

Groundwater level declines are largely associated with natural processes and human activities. In particular, the drivers of groundwater change can be more complex during meteorological drought owing to human activities. However, disentangling their specific contribution remains poorly understood. By focusing on semiarid ecosystems in the northern Yellow River Basin - the Ordos - here we elucidate the impact of human activities on the propagation of meteorological droughts to groundwater systems. To comprehensively analyze groundwater variations, we employ the K-means, categorizing them into four distinct patterns. Based on the Pearson correlation coefficient analysis between standardized precipitation index (SPI) and groundwater depth (GWD), we found that the majority of lag time for GWD response to SPI is less than 3 months, and the drivers influencing GWD are classified into three categories: SPI, human activities related to SPI, and human activities unrelated to SPI. Our results reveal that both meteorological droughts and human activities jointly influence GWD across the entire region. Notably, human activities unrelated to SPI have the greatest impact in the irrigation district of Ordos, followed by the western part of Ordos and the Mu Us sandy land in central Ordos. Our findings can guide us to formulate effective drought management policies and practices in semiarid regions. [ABSTRACT FROM AUTHOR]

The quality and level of groundwater tables have rapidly declined because of intensive pumping in Punjab (Pakistan). For sustainable groundwater supplies, there is a need for better management practices. So, the identification of potential groundwater recharge zones is crucial for developing effective management systems. The current research is based on integrating seven contributing factors, including geology, soil map, land cover/land use, lineament density, drainage density, slope, and rainfall to categorize the area into various groundwater recharge potential zones using remote sensing, geographic information system (GIS), and analytical hierarchical process (AHP) for Punjab, Pakistan. The weights (for various thematic layers) and rating values (for sub-classes) in the overlay analysis were assigned for thematic layers and then modified and normalized using the AHP. The result indicates that about 17.88% of the area falls under the category of very high groundwater potential zones (GWPZs). It was found that only 12.27% of the area falls under the category of very low GWPZs. The results showed that spatial technologies like remote sensing and geographic information system (GIS), when combined with AHP technique, provide a robust platform for studying GWPZs. This will help the public and government sectors to understand the potential zone for sustainable groundwater management. [ABSTRACT FROM AUTHOR]

In recent years, pollution stemming from pharmaceuticals has garnered widespread global concern, which exacerbates the ecological risk to both surface and groundwater. In the current study, Fe and O co-embedded biochar (Fe-O-BC) was synthesized through a one-step pyrolysis procedure with corncob serving as the feedstock. The fabricated Fe-O-BC catalysts were characterized by various techniques and were employed for the activation of peroxymonosulfate (PMS) to degrade tetracycline (TC). TC was rapidly degraded within 40 min, with a degradation rate of 0.1225 min−1, which was much higher than those for O-BC/PMS (0.0228 min−1) and Fe-BC/PMS (0.0271 min−1) under the same conditions. The effects of PMS dosage, Fe-O-BC dose, initial pH value and coexisting anions for TC degradation were investigated. Finally, the mechanism of TC oxidation in the catalytic system was implored through experiments of determining the active sites and radical scavenging experiments. The C-O-Fe bond in the catalyst was confirmed to be the dominant active sites accelerating TC degradation. Free diffused HO•, the surface-bound HO• and SO4•− and O2•−participated in the reaction and absorbed SO4•−, and HO• predominantly contributed to TC degradation. This study provides an efficient and green alternative for pharmaceutical wastewater treatment by Fe and O co-doped catalyst-induced heterogeneous process. [ABSTRACT FROM AUTHOR]

Drained wetlands are thought to be carbon (C) source hotspots, and rewetting is advocated to restore C storage in drained wetlands for climate change mitigation. However, current assessments of wetland C balance mainly focus on vertical fluxes between the land and atmosphere, frequently neglecting lateral carbon fluxes and land‐use effects. Here, we conduct a global synthesis of 893 annual net ecosystem C balance (NECB) measures that include net ecosystem exchange of CO2, along with C input via manure fertilization, and C removal through biomass harvest or hydrological exports of dissolved organic and inorganic carbon, across wetlands of different status and land uses. We find that elevating water table substantially reduces net ecosystem C losses, with the annual NECB decreasing from 2579 (95% interval: 1976 to 3214) kg C ha−1 year−1 in drained wetlands to −422 (−658 to −176) kg C ha−1 year−1 in natural wetlands, and to −934 (−1532 to −399) kg C ha−1 year−1 in rewetted wetlands globally. Climate, land‐use history, and time since water table changes introduce variabilities, with drainage for (sub)tropical agriculture or forestry uses showing high annual C losses, while the net C losses from drained wetlands can continue to affect soil C pools for several decades. Rewetting all types of drained wetlands is needed, particularly for those formerly agriculture‐used (sub)tropical wetlands where net ecosystem C losses can be largely reduced. Our findings suggest that elevating water table is an important initiative to reduce C losses in degraded wetlands, which could contribute to policy decisions for managing wetlands to enhance their C sequestration. [ABSTRACT FROM AUTHOR]

This study investigates the chemical characteristics, formation, and sources of inorganic nitrogen (IN) of shallow groundwater across the Sanjiang Plain, aiming to enhance drinking water safety management and pollution control. A total of 167 groundwater and 27 surface water samples were collected for constituents and isotopes (H2 and O18). The hydrogeochemical characteristics showed that the major type is HCO3‐ Ca·Mg, with low total dissolved solids and a neutral to weak alkaline nature. Rock weathering processes govern the hydrochemical composition of groundwater. Hydrogen and oxygen stable isotopes analyses revealed that precipitation serves as the main water source. In alluvial areas, oxidative conditions lead to the enrichment of NO3‐N concentrations, with sewage, manure, and fertilizers being the primary IN sources. In lacustrine areas, intensive rice cultivation results in reductive conditions and strong denitrification processes, causing the loss of NO3‐N and leaving NH4‐N as the dominant IN form. Organic matter mineralization is likely a more significant contributor to NH4‐N concentrations than ammonium fertilizers. These findings provide valuable information for further research on natural sources and groundwater pollution in areas with similar hydrogeological conditions. Practitioner Points: Rock weathering processes govern the hydrochemical composition of groundwater, and precipitation serves as the main water source.In alluvial areas, oxidative conditions lead to the enrichment of NO3‐N. In lacustrine areas, intensive rice cultivation results in reductive conditions and strong denitrification processes.Organic matter mineralization is likely a more significant contributor to NH4‐N concentrations than ammonium fertilizers.These findings provide references for water management and information for further research on natural sources and groundwater pollution in areas with similar hydrogeological conditions. [ABSTRACT FROM AUTHOR]

Water plays a significant role in human life. However, the contamination of groundwater by heavy metals (HMs) has profound implications for public health. Industrialization, urbanization, and agricultural activities are turning out to be major causes for the increasing concentration of HMs in rapidly industrializing areas like Rohtak district, Haryana, India. The current study aimed at evaluating and predicting the health hazards associated with the radical rise of HMs in the groundwater of Rohtak district. For this purpose, 45 seasonal‐based groundwater samples were collected from five blocks in Rohtak district, namely Kalanaur, Meham, Lakhan Majra, Rohtak City, and Sampla, both during pre‐ and post‐monsoon seasons. Besides physicochemical analysis, these groundwater samples were analyzed for the contamination of HMs. The findings revealed that groundwater samples were relatively more contaminated during the post‐monsoon period rather than pre‐monsoon. The water quality index (WQI), devised to classify water quality into specific classes, depicted the Kalanaur region as "very poor." Another index named the HM pollution index (HPI) denoted the levels of HMs and categorized Kalanaur as most deteriorated, followed by Meham, Lakhan Majra, Sampla, and Rohtak City. Additionally, principal component analysis (PCA) was employed that showed a significant variation in the distribution pattern of HMs, with the major load being attributed to PC1 and PC2 for both seasons. Pearson's correlation analysis indicated a significant association of pH (R2 = 0.917) with HMs (specifically for Cd and Cr). In terms of health risk assessment, carcinogenic human health risk due to Pb and Cr was found to be higher in children than adults. Non‐carcinogenic risk, indicative of harmful human health effects, apart from cancer, was calculated in terms of hazard quotient (HQ) and hazard index (HI). Results of the same, designated "children" as a vulnerable category compared with "adults," especially in the Kalanaur, Sampla, and Rohtak City blocks of the study area. The results thus reiterated that Kalanaur is the most contaminated block among the five blocks chosen and should be given urgent attention. The study holds importance as it provides a framework regarding the methodology that should be adapted for the evaluation, management, and protection of groundwater at a regional level, which could further be replicated by environmentalists and hydrogeologists across the world. Practitioner Points: Water logging is one of the most common problems in Kalanaur block of Rohtak district, responsible for causing groundwater pollution.Cadmium and lead pollution was prevalent in Rohtak due to electroplating industries, paint industry, automobile sector, and industrial discharge.Bioremediation is one of the suitable techniques that can be used for the treatment of groundwater that involves the use of microorganisms.Efficient use of groundwater resources is necessary for sustainable development. [ABSTRACT FROM AUTHOR]

Due to the overexploitation of deep groundwater, the largest cone of depression in the world has formed in the North China Plain. This led to severe geological hazards, including land subsidence and ground fissures, and also caused economic losses. The prevention and treatment of subsidence needs to rely on the accurate prediction of subsidence amount. According to the one‐dimensional consolidation theory and effective stress principle, combined with stratum structure, groundwater flow, stress distribution, and so forth, the high‐pressure consolidation test results of 569.6 m deep borehole soil samples are adopted; with a specific focus on stress and deformation parameters under exploitation of groundwater condition, the soil‐water coupling prediction model of groundwater level lowering depth and land subsidence has been established. Verification with measured subsidence data near the study sites demonstrated that the predicted curve is consistent with the measured one and the differences between them are acceptable. The model can be applied in different areas after making adjustment based on different regional stratigraphic structures. Its key advantage lies in the ability to provide land subsidence prediction for areas lacking monitoring data, making it highly valuable for widespread application. Practitioner Points: There is a compressible stratum structure; it is the internal factors of land subsidence.The groundwater level decline causes the soil body stress to change. It is land subsidence of the external factors.Based on the one‐dimensional consolidation theory and by combining stratigraphic structures, groundwater flow, and stress distribution, a ground settlement prediction model was established. [ABSTRACT FROM AUTHOR]

Groundwater in the McMurdo Dry Valleys of Antarctica is commonly enriched in calcium and chloride, in contrast to surface and groundwater in temperate regions, where calcium chemistry is largely controlled by the dissolution of carbonates and sulfates. These Antarctic Ca-Cl brines have extremely low freezing points, which leads to moist soil conditions that persist unfrozen and resist evaporation, even in cold, arid conditions. Several hypotheses exist to explain these unusual excess-calcium solutions, including salt deliquescence and differential salt mobility and cation exchange. Although the cation exchange mechanism was shown to explain the chemistry of pore waters in permafrost cores from several meters depth, it has not been evaluated for near-surface groundwater and wetland features (water tracks) in which excess-calcium pore-water solutions are common. Here, we use soluble salt and exchangeable cation concentrations to determine whether excess calcium is present in water-track brines and if cation exchange could be responsible for calcium enrichment in these cold desert groundwaters. We show that calcium enrichment by cation exchange is not occurring universally across the McMurdo Dry Valleys. Instead, evidence of the present-day formation of Ca-Cl–rich brines by cation exchange is focused in a geographically specific location in Taylor Valley, with hydrological position, microclimate, soil depth, and organic matter influencing the spatial extent of cation exchange reactions. Up-valley sites may be too cold and dry for widespread exchange, and warm and wet coastal sites are interpreted to host sediments whose exchange reactions have already gone to completion. We argue that exchangeable cation ratios can be used as a signature of past freeze-concentration of brines and exchange reactions, and thus could be considered a geochemical proxy for past groundwater presence in planetary permafrost settings. Correlations between water-track organic matter, fine sediment concentration, and cation exchange capacity suggest that water tracks may be sites of enhanced biogeochemical cycling in cold desert soils and serve as a model for predicting how active layers in the Antarctic will participate in biogeochemical cycling during periods of future thaw. [ABSTRACT FROM AUTHOR]

Worldwide wetland loss over the past 50 years has made wetland conservation a public policy priority, leading to an increase in wetland restoration programs. However, predicting long‐term restoration outcomes remains difficult. The monitoring of these programs rarely exceeds 5–10 years, forcing wetland managers to rely on short‐term success criteria that may be criticized by the scientific community. Our objective was to assess the significance of four short‐term success criteria (Carex ssp. shoot density, Salix ssp. survival, invasive species cover, and hydrologic dissimilarity to reference sites) used in a restoration program of 12 wetlands monitored for 5 years post‐restoration in predicting restoration outcomes 15 years post‐restoration. We defined the success of restoration efforts after 15 years using a cluster analysis‐based approach, and the clusters were described using principal coordinate analysis and Tukey's post hoc honest significant difference test. Finally, we assessed the pertinence of each short‐term success criteria in predicting long‐term restoration outcomes using Pearson correlation tests and spatial regressive models. Our results demonstrate that stress‐based short‐term success criteria can be reliable predictors of longer‐term success for communities with shallow water tables, whereas target‐species‐based short‐term success criteria are not. Hydrologic dissimilarity to the reference site was appropriate for willow‐sedge community outcome predictions, while invasive species cover was best for sedge community outcome predictions. For communities in drier habitats, such as the willow‐herb community, none of the tested short‐term success criteria were significant predictors of long‐term restoration outcomes, and further research is required to identify suitable short‐term success criteria. [ABSTRACT FROM AUTHOR]

Beaver‐based restoration techniques seek to assist with the recovery of stream systems that have been damaged, degraded, or destroyed. In addition to reintroducing beaver, restoration practitioners have sought to mimic the influence of beaver dams on stream processes by building beaver dam analogs (BDAs). Stream restoration has been criticized for a lack of extended monitoring and a dearth of empirical evidence for the efficacy of BDAs. Here, we extend early and previously reported 1‐ to 2‐year monitoring of five BDAs on a low‐gradient stream lacking woody riparian vegetation to 3–6 years, depending on the parameter examined. BDAs raised groundwater near the stream and did not affect water temperatures during the duration of monitoring. Consistent with elevated groundwater levels, riparian willow cuttings grew 2.8–9.6 times more when planted near BDAs than far from BDAs, which was more than the 1.3‐ to 1.4‐fold difference after the first growing season. In contrast, a short‐term association between BDAs and willow survival disappeared in the long term. Likewise, sediment aggradation above the upstream BDA 1 year after construction reversed completely 4 years later, probably due to structural damage during high flows that could not be repaired until flows abated. Annual peak flow levels explained over 80% of the variation in the number of structures requiring annual repair. Our results suggest that BDA‐based restoration should account for both the costs of structure maintenance during project planning and the importance of long‐term monitoring during project assessment. [ABSTRACT FROM AUTHOR]

The groundwater level divides the soils into unsaturated zone and saturated zone, imposing an indispensable effect on the soil–pile interaction behavior. In this work, the groundwater level is introduced into soil–pile group interaction models for advancing the dynamic impedance research of pile groups. The motion equation of pile groups is modeled by the finite element method. The vibration solution of soils considering the groundwater level is solved via the precise integration method, which is utilized as the kernel function to construct the boundary integral equation. The coupled finite element method (FEM) and boundary element method (BEM) establishes the unsaturated soil–pile group interaction equation, which is further solved based on the soil–pile compatibility condition. After confirming the reliability of the above theory, parametric analyses are provided to discuss the effect of a series of key parameters on the impedance function of pile groups. [ABSTRACT FROM AUTHOR]

For all its importance to the Green Revolution, groundwater is India's most valuable and vulnerable natural resource. This is especially true in Punjab and Haryana, two of India's most agriculturally advanced states. Between 2004 and 2017, groundwater levels in Punjab and Haryana fell by 7 and 5 m, respectively. This study aims to evaluate regional groundwater extraction trends and assess the productivity of groundwater irrigation for rice and wheat, the two most significant crops in Punjab and Haryana. The results indicate significant disparities in groundwater irrigation and economic productivity in both inter-state and intra-state settings. [ABSTRACT FROM AUTHOR]

Super-high density olive orchards may increase profitability for table olive producers. However, water needs and fruit damage could limit their viability. Deficit irrigation scheduling would reduce the amount of water required, but rehydration before harvest is extremely important. The aim of this work was to compare a typical deficit farm management model with a regulated deficit irrigation one based on the plant water status. The experiment was carried out during three seasons in a three years-old (4 × 1.5 m) commercial table olive orchard. In both irrigation scheduling plots, seasonal amount of applied water was similar. Irrigation treatments were: common farm management (CFM), an almost constant rate of irrigation, and Regulated deficit (RDI) based on midday shaded water potential. Vegetative measurements suggested that RDI increased the external surface of the hedge, and this was related with greater yield in this treatment. Significant differences were found in of fruit size at harvest in some seasons, with larger fruits in RDI compared to CFM. However, fruit damage occurred during mechanical harvest in both irrigation managements, despite the higher skin firmness in RDI, and shows the need to carry out postharvest treatments to improve the quality of the final product. Accurate control of the tree water status would allow optimizing the amount of water available for table olive orchards. [ABSTRACT FROM AUTHOR]

Pump‐and‐treat technologies are widely used in groundwater remediation and site cleanup. Such technologies involve pumping contaminated groundwater to the surface for treatment. Following treatment, the water is often reinjected back into the aquifer (referred to as pump‐treat‐inject or PTI) for potential reuse. The treatment system is often designed to remove dissolved‐phase contaminants in groundwater such that water meets applicable cleanup standards (herein referred to as "full treatment"). However, in some cases, the treatment system may not effectively reduce the dissolved‐phase concentrations (herein referred to as "partial treatment") for some of the contaminants present in groundwater. Modeling PTI under partial treatment conditions is challenging because contaminant concentrations in injected water depend on the pumped water concentrations and the system treatment efficiency. Essentially, the injected water concentration (a transport model input) is unknown prior to transport simulation. This study presents a novel iterative approach to modeling PTI under partial treatment scenarios, where the injected water concentration is linked to the modeled pumped water concentration. The method was developed for a complicated three‐dimensional (3D) flow and transport modeling study conducted for a confidential remediation site where PTI with partial treatment was applied. However, due to the complexity of the 3D model and the confidential information of the site, a simple two‐dimensional (2D) numerical model is presented to demonstrate the iterative method. The 2D model test runs and the 3D model application in a remediation site showed that the iterative simulation results quickly converged to a viable final solution. [ABSTRACT FROM AUTHOR]

In response to the drawbacks of low collection efficiency, poor real-time performance, and inability to achieve automation in traditional handheld water level sensors for underground water level monitoring in rail transit engineering foundation pits, as well as the fact that existing water level automation equipment mostly uses RS485 communication, which has disadvantages such as short data transmission distance, complex wiring and structure, this paper conducted a detailed study of the working principle of water level sensors and independently developed an integrated water level automation sensor with high integration based on MCU design. By using PowerBus interface and MODBUS protocol, data communication between the water level sensor and the collection module was achieved. Low power consumption sleep mode was adopted to achieve ultra long continuous monitoring of underground water level in rail transit engineering foundation pits, meeting the requirements of on-site monitoring conditions of foundation pits. In the groundwater level monitoring project of a certain rail transit engineering foundation pit, the groundwater level data collected by the integrated water level automation sensor was compared and analyzed with the data obtained by a manually held water level gauge. The results shows that the data accuracy collected by the integrated water level automation sensor is better than 20 mm, which can meet the monitoring requirements of the groundwater level in the foundation pit. [ABSTRACT FROM AUTHOR]

1-Introduction Landforms show different patterns over time and in different spatial scales and climates, knowing the temporal and spatial patterns of landforms in each region can provide the possibility of predicting and detecting the potential of Groundwater in a similar spatial situation. Due to Iran being among the dry and semi-arid countries of the world and the existence of inherent limitations of Groundwater water resources, proper location for exploring and maintaining the sustainable potential of Groundwater is of particular importance. The importance of these resources in the southern plains of Alborz is twofold due to the population density and location in a dry and semi-arid climate, which requires the exploration of Groundwater. A complete understanding of the system, forecasting the current and future conditions, as well as presenting the environmental indicators considered by geomorphologists by providing geostatistical methods, in addition to saving money and time, can determine the places where there is a higher probability of having desirable aquifers. Rivers represent to a great extent the geomorphic nature of any region. The appearance patterns of the river can be classified into four main groups, which are straight channels, sinuous meandering and severe meandering. The channel pattern is derived from a set of characteristics that can create a direct relationship with the state of Groundwater infiltration and, as a result, changes in the level of water stagnation. Factors such as changes in river flow, sediment conditions, land surface slope, river strength, vegetation cover, etc. cause changes in the pattern of the river along its path. These factors are considered to be the most important factors of Groundwater penetration in the plain and downstream areas of the mountain fault line (Kennik line). Therefore, it can be concluded that with the change in the river pattern, the status of the groundwater level should also change. In the field of investigating the real or actual potential of Groundwater, there have been scattered studies that based on the environmental changes during a certain period, it is possible to find out the probability of the existence of Groundwater in that area. The purpose of the current research is to find the potential of Groundwater resources according to the changes of river platforms in the western plains of Tehran, Alborz and Qazvin. In this present research, after identifying and mapping the river channels in the western and southern plains of Tehran, Alborz and Qazvin provinces, the sinuosity characteristics of each of the rivers were determined and the studied area was divided into 67 intervals according to the river patterns and calculated independently. Also, this article has tried to determine the influence of river parameters on the changes of Groundwater parameters by identifying the border of river pattern changes and its relationship with the clustering of Groundwater parameters according to statistical classification. 2-Methodology In order to evaluate the role of river platforms on water table changes, information on well discharge rate, electrical conductivity and water table depth of 23559 observation wells from Iran Water Resources Organization was prepared. Also, the morphometric characteristics of the rivers and the resulting patterns were identified and their relationship with the average, maximum and minimum depth of the water table, discharge and electrical conductivity were calculated. 26 rivers were used as the main rivers of the western regions of Tehran, Karaj and Qazvin provinces. Then, each river was divided into two or more parts by means of morphometric changes along the river course and according to the separated sinuosity. According to the pattern of rivers, the studied area was divided into 67 intervals and drawn. Arc Gis 10.5 software was used for digitization and data processing. The sinuosity coefficient of each river was calculated in terms of the ratio of the length of the main course of the river to the length of the valley or the linear length of the river. By determining the river's sinuosity coefficient (Figure 2), each river was divided into four straight, sinusoidal, meandering, and severe meandering patterns according to the average of the determined coefficient. Using SPSS version 23 software, hierarchical cluster analysis (HCA) was used to classify the characteristics of groundwater in 26 rivers and its tree diagram was drawn. Considering the non-parametric nature of the data of each cluster, the significant difference of the parameters was determined by the one-way variance and Kruskal-Wallis tests. Also, in order to determine the effect of river parameters on changes in the depth of Groundwater in each model, hierarchical cluster classification was done and its significance level according to the number of variables and parametric or non-parametric data using one-way variance, independent t, Kruskal-Wallis and Man-Whitney and Pearson correlation test were calculated. The coefficient of explanation and the graph of changes in Groundwater parameters were also estimated by Excel software. 3-Results The results showed that all three groundwater parameters have a strong correlation and a significant difference of 95% in straight, sinusoidal and Pichanrodi patterns. Also, the river sections that have a sinusoidal pattern with a sinuosity coefficient of 1.14 and an average flow rate of 12.6 liters per second have the highest amount of water flow compared to the other two patterns. The relationship between the sinuosity coefficient of the river and the amount of electrical conductivity and the depth of the sedimentation surface is linear and non-random, and moving from the straight pattern to the winding pattern, the amount of electrical conductivity and the depth of the sedimentation surface increases. 4-Discussion & Conclusions The results showed that each of the rivers, in addition to having an independent pattern, also had pattern changes along its course, which can be identified and separated. In addition, the areas under the influence of rivers can be separated into two classes or clusters in terms of the status of Groundwater parameters. In fact, the significant difference in the sinuosity coefficient of rivers in areas that have significant differences in terms of Groundwater changes can indicate the influence of both parameters on changes in environmental conditions such as the morphogenic state, topography, hydrology, lithology and morphology of the region. Therefore, the changes in the sinuosity coefficient can be considered as evidence of the changes in the Groundwater, and the results of the verification show the influence of the platform of each river section on the changes in the Groundwater. Also, the degree of correlation and significance of the twisting coefficient of the river with the changes in flow parameters, depth of water table and electrical conductivity also shows that all three Groundwater parameters have a strong correlation and a significant difference of 95% in straight, sinusoidal and meandering river patterns. In general, the results of this research showed that due to the great relationship between patterns or river platforms on Groundwater, this index can be used in large and small intervals to evaluate the quantitative and qualitative changes of Groundwater and it can be used for Other similar areas also extended. Also, the results of this study show that river geomorphic studies before carrying out implementation plans can be the basis for reducing the error in determining the appropriate place to feed the aquifer or dig an Groundwater well. [ABSTRACT FROM AUTHOR]

This study employed a comprehensive methodology, which combines the use of multispectral images and field inclinometer data. The unique approach involves using multispectral images to monitor the topographic and hydrological changes caused by a large-scale landslide at Caoling in Taiwan. The field inclinometer data, collected at regular intervals, were then integrated into a geographic information system. This system was used to estimate the potential sliding volume of the landslide, which was then compared with changes in the digital terrain model data for Caoling. The multispectral images of Caoling were examined to determine the changes in its topographic and hydrological indices after the landslide. The convex slope at Caoling moved in the progressive backward mode with increased groundwater level and slope displacement under rainfall conditions. The potential sliding volume of the landslide was 6.4 × 106 m3. The results of this study indicate that the changes in topographic and hydrological indices after a landslide enable the identification of the local surficial changes caused by the landslide. Changes in the rate of slope movement show a high correlation to the fluctuation of groundwater level. Reactivation of the large-scale landslide is attributable to hillslope, geologic and topographic characteristics, including toe creek incision, surficial erosion, and torrential rainfall brought by typhoons. Moreover, post landslide topographic monitoring through drone images, which provide high-resolution and real-time data, plays a crucial role in identifying a landslide's reactivation mechanism. This, in turn, enables effective disaster mitigation strategies to be implemented. [ABSTRACT FROM AUTHOR]

Groundwater contamination from non-engineered landfills has been extensively documented. However, there is a gap in extensive field research regarding whether engineered landfills can also contribute to groundwater contamination. We selected 62 engineered municipal landfills in Eastern China and collected both leachate samples from the landfills and groundwater samples from nearby wells. Through the analysis of inorganic solute indicators in both groundwater and leachate samples, we explored the impact of landfill leachate on the inorganic solute composition of groundwater. Our findings revealed that over half of the groundwater samples surrounding the landfill sites exceeded recommended drinking water limits for inorganic solutes. The correlation analysis demonstrates a significant relationship between Cl−, SO42−, Na+, and K+ levels in leachate and groundwater, highlighting the direct impact of landfill activities on groundwater quality. Moreover, specific characteristics of the landfill, such as its age, the total waste volume, and geographic location, were found to influence the inorganic solute composition in the groundwater. This effect was apparent in the positive correlations between the age of the landfill and NH3-N, Ca2+, and Mg2+ levels in groundwater, the total waste volume of the landfill and Ca2+ content in groundwater, and the latitude of the landfill and Cl− and HCO3− concentrations in groundwater. This work carries implications for assessing environmental risks associated with engineered landfills and enhancing landfill design, management, and monitoring practices. [ABSTRACT FROM AUTHOR]

The presented study investigates the dynamics of DOC concentrations in headwater peatbog areas with respect to the extreme rainfall-runoff (R-R) events hydrometeorological catchment preconditions (23 variables in total). The main data sources were automatic devices for monitoring of groundwater level, discharges and rainfalls providing data in 10 min steps installed in the Vydra River catchment and one automatic water sampler ISCO in sub-catchment of the Rokytka River basin in the Šumava (Bohemian Forest) National Park. The study period was 2018–2021, in which 18 R-R events were analysed. Data of DOC variability and catchment conditions were analysed using Spearman's correlation coefficient, Principal Component Analysis and DOC/Q hysteresis loops. Changes in groundwater level and discharges had the greatest influence on DOC concentrations. Higher mean and maximum DOC were measured during events after a longer period without an extreme R-R event. The greater lag time of maximum DOC after peak flow and the higher mean DOC during the event were primarily due to hydrometeorological preconditions of the catchment. The highest DOC was in autumn after the previous summer period with low discharges and low groundwater levels. DOC was also positively correlated with air and water temperatures. [ABSTRACT FROM AUTHOR]

Groundwater is a vital factor affecting the stability of water-rich slope of open-pit mine, and the distribution of groundwater inside water-rich slope is always uncertain. To investigate the uncertainty of groundwater distribution inside the water-rich slope, based on the engineering background of DEZIWA open-pit mine, this paper adopts the research method of field investigation and test (single and multiple borehole pumping tests), numerical simulation (Visual MODFOW), and theoretical analysis (nonlinear fitting theory, distribution fitting theory, and one-sample Kolmogorov–Smirnov test) to study the uncertainty of the distribution of groundwater table line within the water-rich slope of open-pit mine. Results obtained from the above research indicate that, Visual MODFLOW is an effective tool for obtaining groundwater distribution information inside the water-rich slope of open-pit mine. When the open-pit mine excavated to the final boundary, it is found that within multiple cross-sections of the southern and western regions of water-rich slope of the open-pit mine, groundwater table line can all be delineated by a series of 3-term Fourier equations, which can be characterized by identical equation forms but varying fitting coefficients. Furthermore, based on the findings of distribution fitting and one-sample Kolmogorov–Smirnov test, it becomes evident that the probability distribution of the fitting coefficients of the aforementioned 3-term Fourier equations can all be described by the normal distribution models. Use the established normal distribution models in this paper, uncertainty of the groundwater distribution within the water-rich slope of DEZIWA open-pit mine can be described indirectly and quantitatively, and the research methods of this paper can provide a meaningful reference to the slope engineering with similar conditions. [ABSTRACT FROM AUTHOR]

Landslides are one of the most common geohazards, posing significant risks to infrastructure, recreation, and human life. Slope stability analyses rely on detailed data, accurate materials testing, and careful model parameter selection. These factors are not always readily available, and estimations must be made, introducing uncertainty and error to the final slope stability analysis results. The most critical slope stability parameters that are often missing or incompletely constrained include slope topography, depth to water table, depth to failure plane, and material property parameters. Though estimation of these values is common practice, there is limited guidance or best practice instruction for this important step in the analysis. Guidance is provided for the estimation of: original and/or post-failure slope topography via traditional methods as well as the use of open-source digital elevation models, water table depth across variable hydrologic settings, and the iterative estimation of depth to failure plane and slope material properties. Workflows are proposed for the systematic estimation of critical parameters based primarily on slide type and scale. The efficacy of the proposed estimation techniques, uncertainty quantification, and final parameter estimation protocol for data-sparse landslide analysis is demonstrated via application at a landslide in Colorado, USA. [ABSTRACT FROM AUTHOR]

Investigations have revealed the presence of microplastics in both soil and groundwater, but the migration characteristics from soil to groundwater remain incompletely understood. In this study, two sampling sections consisting of soil-groundwater-river water were established near Lianxi Bridge and Xilin Bridge along the Jiuxi River in Xiamen. A total of 22 soil samples, 36 groundwater samples, and 18 river water samples were collected. Microplastics were detected in all samples with an abundance range of 392–836 n/kg in soil (mean, 655 ± 177 n/kg), 0.58–2.48 n/L groundwater (mean, 1.23 ± 0.42 n/L), and 0.38–1.80 n/L in river water (mean, 0.86 ± 0.41 n/L). Flakes predominantly constituted the shape of microplastics found in soil, while fibers dominated those present in water. Black, yellow, and red were the dominant color types. Polyamide (PA) and polyethylene (PE) were the main components of microplastics within soils, whereas polyethylene terephthalate (PET), polypropylene (PP), and PA prevailed within water. Microplastic particle sizes ranged from 39 to 2498 μm in soils, mainly from 29 to 3394 μm in water. The upstream section displayed higher abundances of microplastic compared to the downstream, revealing the soil particles having an intercepting effect on microplastics. The distribution and migration of microplastics in soil and groundwater are affected by many factors, including natural and anthropogenic factors, such as soil depth, soil properties, pore structure, hydrodynamics, hydraulic connections between groundwater and surface water, the extensive utilization and disposal of plastics, irrational exploitation of groundwater, and morphology and types of microplastics. These research findings contribute to a better understanding of the pathways, migration capacity, and influencing factors associated with microplastic entry into groundwater, thereby providing valuable technical support for the development of strategies aimed at controlling microplastic pollution. [ABSTRACT FROM AUTHOR]

The present study focused on the distribution of uranium in groundwater samples collected from various sources in the Chikkaballapur district and its associated risk in humans. Seventy-five groundwater samples were collected during pre-monsoon and post-monsoon seasons and were analysed for uranium concentration along with different water quality parameters. The uranium concentration ranged from 0.23 to 285.23 µg/L in the pre-monsoon season and from 0.02 to 107.87 µg/L in the post-monsoon season. More than 90% of samples, except a few, were under the safe limits of 60 µg/L as directed by the Department of Atomic Energy (DAE) of India's Atomic Energy Regulatory Board (AERB). The study analysed physicochemical parameters like pH, total dissolved solids (TDS), nitrate, total hardness, phosphate, sulphate and fluoride in collected water samples. Out of all samples, few samples noted higher values of TDS, nitrate and fluoride. Their correlation along with uranium is detailed in the study. Owing to its slightly elevated content, an evaluation of the radiological and chemical hazards associated with uranium consumption was analysed. When the risk resulting from chemical toxicity was evaluated, relatively few samples had a hazard quotient (HQ) score higher than 1, which suggested that the people were vulnerable to chemical danger. This study also evaluates the dangers of elevated uranium levels in groundwater samples to the general public's health. It also acknowledges the importance of routinely evaluating and treating the drinking water sources in the region. [ABSTRACT FROM AUTHOR]

Over the past decade, excessive groundwater extraction has been the leading cause of land subsidence in Taiwan's Chuoshui River Alluvial Fan (CRAF) area. To effectively manage and monitor groundwater resources, assessing the effects of varying seasonal groundwater extraction on groundwater levels is necessary. This study focuses on the CRAF in Taiwan. We applied three artificial intelligence techniques for three predictive models: multiple linear regression (MLR), support vector regression (SVR), and Long Short-Term Memory Networks (LSTM). Each prediction model evaluated the extraction rate, considering temporal and spatial correlations. The study aimed to predict groundwater level variations by comparing the results of different models. This study used groundwater level and extraction data from the CRAF area in Taiwan. The dataset we constructed was the input variable for predicting groundwater level variations. The experimental results show that the LSTM method is the most suitable and stable deep learning model for predicting groundwater level variations in the CRAF, Taiwan, followed by the SVR method and finally the MLR method. Additionally, when considering different distances and depths of pumping data at groundwater level monitoring stations, it was found that the Guosheng and Hexing groundwater level monitoring stations are best predicted using pumping data within a distance of 20 kilometers and a depth of 20 meters. [ABSTRACT FROM AUTHOR]

Due to the pressure on South Africa's irrigated agriculture to improve efficiency and optimal water use, irrigators must consider alternative water sources, such as root-accessible shallow groundwater tables, to supply the crop evapotranspiration requirement. Devising irrigation scheduling strategies that will optimize conjunctive water use is difficult because the contribution of shallow groundwater tables is not directly observed and is a function of irrigation management decisions; as a result, very few irrigators use these strategies. This paper aims to evaluate the profitability of using shallow groundwater tables as a source of irrigation water to satisfy crop evapotranspiration requirements. A bio-economic simulation model consisting of the soil–water–atmosphere–plant model and an economic accounting module was developed to calculate the profitability of conjunctive irrigation practices under different states of nature. The bio-economic simulation model was linked to a differential evolutionary algorithm to optimize the irrigation scheduling decisions. The results showed that irrigators could substantially increase profitability and water use efficiency if they consider the shallow groundwater table in their irrigation decision. About 51% of crop evapotranspiration could originate from shallow groundwater tables, reducing the irrigation requirements substantially without impacting crop yields. Sequential adaptive irrigation decision-making does not improve the bio-economic indicators much since using the shallow groundwater table mitigates the risk of undersupplying water. Therefore, conjunctive water use strategies using shallow groundwater tables economically benefit irrigators. However, a complex interplay exists between irrigation adjustments, crop yields and economic performance in different states, emphasizing the careful consideration of context-specific factors in irrigation management decisions. [ABSTRACT FROM AUTHOR]

Examining the condition of groundwater resources and the impact of droughts is valuable for effective water resources management. Today, machine learning (ML) models are recognized as one of the useful tools in time series predictions. In this study, the groundwater condition of one of the most important aquifers in northwest Iran was investigated using MODFLOW, followed by estimating the groundwater resource index (GRI) utilizing the multivariate adaptive regression spline (MARS) and least squares support vector regression (LSSVR) for a period between 2001 and 2019. Meteorological and hydrological drought indicators along with precipitation and flow rate were used as input variables for prediction. The simulation results revealed a groundwater level decrease since the aquifer withdrawal amount is more than the recharge amount. Besides, results showed that there is a limited interaction between surface water and groundwater resources, mainly caused by the decrease in the river flow and aquifer groundwater level drop. Both ML models performed well in GRI estimation, using groundwater flow, streamflow drought index, standardized precipitation index, and runoff as input variables. The performance of the MARS model with RMSE, MAE, and NSE error evaluation criteria of 0.37, − 0.19, and 0.83, respectively, exerted slightly better results than LSSVR with RMSE, MAE, and NSE of 0.48, − 0.06, and 0.80, respectively. The findings reveal the appropriate performance of both models in forecasting drought indicators, highlighting the necessity of using ML models in hydrology and drought prediction problems. [ABSTRACT FROM AUTHOR]

This study aimed to determine the amount of As and Pb in the water in the Meoqui-Delicias' aquifer and their spatiotemporal dynamics. Twenty-one water sampling points were selected. Seventeen samples were from wells and four were from surface water; two were used for human consumption and the rest for agricultural use. The samples were taken from May 2019 to January 2020 in four sampling events, one for each climatological season of the year. The studied geochemical anomalies seem to be linked to the nature and mechanism of volcanic emplacement. Several samples exhibited high concentrations of arsenic ranging from 1.20 to 156.54 ppb, unlike lead, with low values being the maximum value of 26.32 ppb. These elements (As and Pb) are in the water in Naica, part of the mining district where tons of Au, Ag, Pb, Cu, and Zn were obtained. From a geographical standpoint, it is impossible to establish that these elements are related, even though these elements (As and Pb) are present in the water in Naica, a mining zone where tons of Au and Ag were historically mined. [ABSTRACT FROM AUTHOR]

Human activities play a key role in landscape evolution. Mining is one of the most important of these since it changes large parts of the Earth's surface. In abandoned mines and quarries, pit lakes are quite common due to water table blocking. These lakes have remarkable ecological characteristics, but they are still poorly understood. Northwestern Spain has a long tradition in the use of slate for roofs. This exploitation, mostly open-pit, has caused a great transformation in the landscape including the generation of pit lakes. In this work, 27 pit lakes in abandoned slate quarries areas have been analysed using orthophotos of different years, UAV (unmanned aerial vehicle) images and field work. In each lake, the topographic context, geomorphological dynamics, morphometric parameters (including depth), pH, and ecological variables were measured. Other uses for these quarry pit lakes and their significance as a new geo-ecological environment are also discussed. The results show different types of pit lakes and, consequently, different potential uses in each case. Only six offer good conditions for recreational uses, whereas the rest (21) show slope instability or poor water quality. [ABSTRACT FROM AUTHOR]

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

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

An artificial intelligence-based geostatistical optimization algorithm was developed to upgrade a test Iranian aquifer's existing groundwater monitoring network. For that aquifer, a preliminary study revealed that a Multi-Layer Perceptron Artificial Neural Network (MLP-ANN) more accurately determined temporally average water table elevations than geostatistical kriging, spline, and inverse distance weighting. Because kriging is usually used in that area for water table estimation, the developed algorithm used MLP-ANN to guide kriging, and Genetic Algorithm (GA) to determine locations for new monitoring well location(s). For possible annual fiscal budgets allowing 1–12 new wells, 12 sets of optimal new well locations are reported. Each set has the locations of new wells that would minimize the squared difference between the time-averaged heads developed by kriging versus MLP-ANN. Also, to simultaneously consider local expertise, the algorithm used fuzzy inference to quantify an expert's satisfaction with the number of new wells. Then, the algorithm used symmetric bargaining (Nash, Kalai–Smorodinsky, and area monotonic) to present an upgradation strategy that balanced professional judgment and heuristic optimization. In essence, the algorithm demonstrates the systematic application of relatively new computational practices to a common situation worldwide. [ABSTRACT FROM AUTHOR]

Due to yearly uneven rainfall distribution, exsiccation of water availability, specifically during the summer in the agricultural field in Saurashtra, is a usual scenario. Saurashtra region's land formation contains Basalt rock. The area is categorized under the semi-arid region. Hence, the Groundwater condition was observed to be poor as the self-characteristic of land for water-storage capacity for the Basalt is negligible within its strata. Mining Engineering and Groundwater Improvement Techniques were incorporated to find a way out of water stress conditions. An experimental study was carried out for mass blasting with the permission of the Government body and an expert team of mining explosions at the study area within the catchment of check dams and river beds. A group containing five borewells was blasted at a 27, 18, and 9 m depth, respectively. In each borehole, 15 blasts of 2.76 unit explosion were exploded together by sealing a cover of sand over it. The impact assessment of 30 wells was monitored Post-blast within the range of 400m of the Bore Blasting Technique (BBT) performed. As a result, a rise in water level up to 19m has been recorded near the streamline of BBT performed. In addition, the movement of the water was diverted from its parental aquifer to the observed dug wells. Hence, it is concluded that channelizing the groundwater can be possible by incorporating BBT in the basalt region, and identical improvement can also possible interms of fractured basalt rock and availability of water in the basalt region. [ABSTRACT FROM AUTHOR]

Groundwater accounting is becoming increasingly important for sustainable societal development. To gain insights into the long-term spatiotemporal changes from 1992 to 2015 regarding groundwater resources in Kumamoto, southern Japan, we analyzed climatological time series, discharge from the groundwater-fed lake (Ezu Lake), and groundwater levels from 94 wells. To explicitly detect temporal changes in these variables and assess potential drivers of change, we used three different trend analyses: the Mann-Kendall Test (MKT), Seasonal Mann-Kendall Test (SMKT), and Innovative Trend Analysis (ITA). Our results revealed a consistently increasing trend in monthly mean temperature, monthly total precipitation, and maximum hourly rainfall. However, a decreasing trend was detected for the discharge rate from the Ezu Lake from 1992 to 2015. Among the 94 investigated groundwater wells, 64 wells showed an upward trend (p ≤ 0.05), while 23 wells showed a downward trend (p ≤ 0.05) for groundwater level. The observed decline in groundwater level is related to the decline in Ezu Lake discharge. However, the increase for the majority of groundwater wells is related to the increased precipitation and applied artificial groundwater recharge as well as a decrease in the groundwater abstraction rate. The ITA outperformed both SMKT and MKT, particularly in detecting minor variations in hydrological time-series data. The results and approach presented in this study can provide a scientific basis for improve groundwater accounting and water resources management in Kumamoto area and other regions with similar climate and socioeconomic conditions. [ABSTRACT FROM AUTHOR]

Groundwater is the most reliable source of freshwater for household, industrial, and agricultural usage. However, anthropogenic interventions in the water cycle have disrupted sustainable groundwater management. This research aims to comprehend the future of groundwater recharge predominantly due to rainfall under changing climate. In this study, predictors of groundwater recharge such as precipitation, land use land cover (LULC), soil type, land slope, temperature, potential evapotranspiration, and aridity index (ArIn) were used for the Punjab region of India over the duration of 34 years, from 1986 to 2019. To simulate future conditions, various climate change scenarios from the CMIP6 report have been incorporated. Different Artificial Intelligence and Deep Learning models, ranging from the straightforward Linear Regression model to the intricate Extreme Gradient Booting (XGBoost), used these parameters as input. Statistical analysis of the models showed that XGBoost is most effective in predicting the groundwater recharge phenomena. Correlation studies revealed precipitation to be the primary contributor to recharge, followed by the ArIn, while soil type and slope are found to have the strongest inverse correlation. The models' resilience and performance were investigated by conducting a k-fold cross-validation analysis. The pattern of groundwater recharge is forecasted for the years 2020 to 2035 across Punjab with different climate change scenarios. The study demonstrates how the Punjab area is mirroring its current status around Shared Socioeconomic Pathway (SSP) 370. Groundwater level estimates confirmed its strong correlation with and dependence on groundwater recharge. The analysis is strengthened by comparing the AI-predicted groundwater recharge with the Central Ground Water Board (CGWB) Punjab's annual estimate. Key points: • Data-driven deep learning models can model groundwater recharge with high accuracy without extensive aquifer parameter data requirement. • Pronounced effect of climate change on groundwater recharge in the future pertaining to the different climate change scenarios (SSPs). • Forecasted groundwater recharge and level data shows significant match with the CGWB, Govt. of India's estimates and observed data. [ABSTRACT FROM AUTHOR]