Explore the vast range of titles available.

Transporting materials and mine staff is a vital link necessary to the production process in underground mines. Deteriorating climatic conditions, mainly due to the increasingly deep mining and the usage of machines, force us to look for solutions to improve the underground mine environmental situation. Another essential factor responsible for deteriorating working conditions is harmful substances and exhaust fumes emitted from diesel engines. Supplying the workplaces with air quantity exceeding requirements such as the minimum velocity of air movement or gas and climatic conditions will allow for maintaining the gas concentration at the appropriate level. One possible way to solve the problems mentioned above is to replace suspended monorails powered by internal combustion engines with new solutions of electrically battery-powered monorails. Electric monorails are not yet widely used in mines; nevertheless, they have many advantages. This article analyzes the exhaust gas parameters from monorail locomotives operating in a hard coal mine and determines the required airflow to maintain permissible concentrations of harmful gases. It also focuses on a comparative analysis of climatic conditions in the development heading, considering the roadway’s functioning with and without using diesel or electric monorail. The study consists of the methodology for predicting climate conditions. Based on the performed analysis, it was shown that using electric monorails could significantly improve working conditions.

Sustainable management of groundwater resources requires a comprehensive understanding of groundwater recharge; including when and under what conditions groundwater recharge occurs. However, recharge is one of the least understood hydrologic processes. Here we show how event‐scale rainfall recharge thresholds vary over a year using a novel network of subterranean drip loggers installed in caves, mines, and tunnels to observe groundwater recharge events. These cannot be used to directly estimate groundwater recharge volumes, but instead detail temporal aspects, such as the rainfall amount required to trigger recharge. We describe how these thresholds vary over time and space from a range of geological, environmental, and climatic conditions. At our Southeast Australian sites, median rainfall recharge thresholds of 10–20 mm in 48 hr were needed to activate recharge. Rainfall events of this magnitude are infrequent, they are expected to change with climate change, and they are fundamentally important for informing groundwater recharge. Plain Language Summary Groundwater is one of Earth's most important natural resources. Groundwater is replenished by the downward flow of water from the land surface to the aquifer, a process technically called groundwater recharge. However, we generally have a poor understanding of when this replenishment occurs, and how much rainfall is needed. This study improves our understanding of groundwater recharge through a sensor network deployed in underground spaces such as tunnels, mines, and caves, located between the soil and the aquifer. Our results come from diverse climates within Australia, where we show that 10–20 mm of rain over a 48 hr period is what is typically needed for recharge to occur. We show that rainfall events of this magnitude are infrequent, and generally caused by specific weather conditions, such as the co‐occurrence of cyclones or fronts with thunderstorms. Our approach can be used globally in suitable lithologies to improve our understanding of when groundwater recharge occurs and after how much rainfall, and how that relates to weather and climate. Such knowledge benefit the sustainable management of this natural resource. Key Points Using loggers deployed in underground spaces we could identify groundwater recharge at the scale of individual weather events Recharge events are uncommon, predominantly occurring after more than 10 mm of rainfall in 48 hr Recharge is site specific and more accurate estimates would be obtained with a better understanding of high magnitude rainfall events

Groundwater is one of the most essential natural resources and is affected by climate variability. However, our understanding of the effects of climate on groundwater recharge (R), particularly in dry regions, is limited. Future climate projections suggest changes in many statistical characteristics of the potential evapotranspiration (Ep) and the rainfall that dictate the R. To better understand the relationship between climate statistics and R, we separately considered changes to the mean, standard deviation, and extreme statistics of the Ep and the precipitation (P). We simulated the R under different climate conditions in multiple semi-arid and arid locations worldwide. Obviously, lower precipitation is expected to result in lower groundwater recharge and vice versa. However, the relationship between R and P is non-linear. Examining the ratio R/P is useful for revealing the underlying relation between R and P; therefore, we focus on this ratio. We find that changes in the average Ep have the most significant impact on R/P. Interestingly, we find that changes in the extreme Ep statistics have much weaker effects on R/P than changes in extreme P statistics. Contradictory results of previous studies and predictions of future groundwater recharge may be explained by the differences in the projected climate statistics.

Droughts, traditionally less associated with high-latitude regions, are emerging as significant challenges due to changing climatic conditions. Recent severe droughts in Europe have exposed the vulnerability of northern catchments, where shifts in temperature and precipitation patterns may intensify drought impacts. This study investigates the dynamics of drought propagation in high-latitude regions, focusing on four key aspects: (1) the typical lag time for drought conditions to propagate from initial precipitation deficits to impacts on soil moisture, streamflow, and groundwater systems; (2) the probability of precipitation deficits leading to these droughts; (3) the key catchment characteristics influencing drought propagation; and (4) the way in which drought propagation has evolved under changing climate conditions. By analyzing long-term observational records from 50 Swedish catchments, the study reveals that drought propagation is highly variable and influenced by a complex interplay of catchment characteristics, hydroclimatic conditions, and soil properties. Soil moisture exhibits the shortest propagation times, often responding within a month to precipitation deficits, while groundwater shows the longest and most variable response times, sometimes exceeding several months. The probability of precipitation deficits propagating into soil moisture droughts is highest, followed by streamflow and groundwater, with these probabilities increasing over time. Across all drought types, annual precipitation and streamflow emerge as the most influential factors governing both propagation time and probability. Although most catchments have become wetter year-round due to climate change, southern catchments are increasingly vulnerable to spring droughts (particularly soil moisture drought), driven by increasing evaporative demand. Despite these hydroclimatic shifts, no significant long-term trends in propagation times or probabilities have been observed over the past 60 years. These findings highlight the need for tailored region-specific water management strategies to address seasonal and regional variations in drought risks, particularly as climate change continues to reshape hydrological regimes.

Despite clear signals of regional impacts of the recent severe drought in California, e.g., within Californian Central Valley groundwater storage and Sierra Nevada forests, our understanding of how this drought affected soil moisture and vegetation responses in lowland grasslands is limited. In order to better understand the resulting vulnerability of these landscapes to fire and ecosystem degradation, we aimed to generalize drought-induced changes in subsurface soil moisture and to explore its effects within grassland ecosystems of Southern California. We used a high-resolution in situ dataset of climate and soil moisture from two grassland sites (coastal and inland), alongside greenness (Normalized Difference Vegetation Index) data from Landsat imagery, to explore drought dynamics in environments with similar precipitation but contrasting evaporative demand over the period 2008–2019. We show that negative impacts of prolonged precipitation deficits on vegetation at the coastal site were buffered by fog and moderate temperatures. During the drought, the Santa Barbara region experienced an early onset of the dry season in mid-March instead of April, resulting in premature senescence of grasses by mid-April. We developed a parsimonious soil moisture balance model that captures dynamic vegetation–evapotranspiration feedbacks and analyzed the links between climate, soil moisture, and vegetation greenness over several years of simulated drought conditions, exploring the impacts of plausible climate change scenarios that reflect changes to precipitation amounts, their seasonal distribution, and evaporative demand. The redistribution of precipitation over a shortened rainy season highlighted a strong coupling of evapotranspiration to incoming precipitation at the coastal site, while the lower water-holding capacity of soils at the inland site resulted in additional drainage occurring under this scenario. The loss of spring rains due to a shortening of the rainy season also revealed a greater impact on the inland site, suggesting less resilience to low moisture at a time when plant development is about to start. The results also suggest that the coastal site would suffer disproportionally from extended dry periods, effectively driving these areas into more extreme drought than previously seen. These sensitivities suggest potential future increases in the risk of wildfires under climate change, as well as increased grassland ecosystem vulnerability.

The Heihe River basin in northwest China depends heavily on both anthropogenic and natural storage (e.g., surface reservoirs, rivers and groundwater) to support economic and environmental functions. The Qilian Mountain cryosphere in the upper basin is integral to recharging these storage supplies. It is well established that climate warming is driving major shifts in high-elevation water storage through loss of glaciers and permafrost. However, the impacts on groundwater–surface-water interactions and water supply in corresponding lower reaches are less clear. We built an integrated hydrologic model of the middle basin, where most water usage occurs, in order to explore the hydrologic response to the changing cryosphere. We simulate the watershed response to loss of glaciers (glacier scenario), advanced permafrost degradation (permafrost scenario), both of these changes simultaneously (combined scenario) and projected temperature increases in the middle basin (warming scenario) by altering streamflow inputs to the model to represent cryosphere-melting processes, as well as by increasing the temperature of the climate forcing data. Net losses to groundwater storage in the glacier scenario and net gains in the permafrost and combined scenarios show the potential of groundwater exchanges to mediate streamflow shifts. The result of the combined scenario also shows that permafrost degradation has more of an impact on the system than glacial loss. Seasonal differences in groundwater–surface-water partitioning are also evident. The glacier scenario has the highest fraction of groundwater in terms of streamflow in early spring. The permafrost and combined scenarios meanwhile have the highest fraction of streamflow infiltration in late spring and summer. The warming scenario raises the temperature of the combined scenario by 2 ∘C. This results in net groundwater storage loss, a reversal from the combined scenario. Large seasonal changes in evapotranspiration and stream network connectivity relative to the combined scenario show the potential for warming to overpower changes resulting from streamflow. Our results demonstrate the importance of understanding the entire system of groundwater–surface-water exchanges to assess water resources under changing climatic conditions. Ultimately, this analysis can be used to examine the cascading impact of climate change in the cryosphere on the resilience of water resources in arid basins downstream of mountain ranges globally.

Water scarcity is a pressing global issue driven by increasing water demands and changing climate conditions. Based on novel estimates of water availability and water use in Chile, we examine the challenges and risks associated with groundwater (GW) withdrawals in the country's central-north region (27–35° S), where extreme water stress conditions prevail. As total water use within a basin approaches the renewable freshwater resources, the dependence on GW reserves intensifies in unsustainable ways. This overuse has consequences that extend beyond mere resource depletion, manifesting into environmental degradation, societal conflict, and economic costs. We argue that the “Day Zero” scenario, often concealed by the uncertain attributes of GW resources, calls for a reconsideration of water allocation rules and a broader recognition of the long-term implications of unsustainable GW use. Our results offer insights for regions worldwide facing similar water scarcity challenges and emphasize the importance of proactive and sustainable water management strategies.

Groundwater recharge (GWR) is a strategic hydrologic variable, and its estimate is necessary to implement sustainable groundwater management. This is especially true in a global warming context that highly impacts key winter conditions in cold and humid climates. For this reason, long-term simulations are particularly useful for understanding past changes in GWR associated with changing climatic conditions. However, GWR simulation at the regional scale and for long-term conditions is challenging, especially due to the limited availability of spatially distributed calibration data and due to generally short observed time series. The objective of this study is to demonstrate the relevance of using a water budget model to understand long-term transient and regional-scale GWR in cold and humid climates where groundwater observations are scarce. The HydroBudget model was specifically developed for regional-scale simulations in cold and humid climate conditions. The model uses commonly available data such as runoff curve numbers to describe the study area, precipitation and temperature time series to run the model, and river flow rates and baseflow estimates for its automatic calibration. A typical case study is presented for the southern portion of the Province of Quebec (Canada, 36 000 km2). With the model simultaneously calibrated on 51 gauging stations, the first GWR estimate for the region was simulated between 1961 and 2017 with very little uncertainty (≤ 10 mm/yr). The simulated water budget was divided into 41 % runoff (444 mm/yr), 47 % evapotranspiration (501 mm/yr), and 12 % GWR (139 mm/yr), with preferential GWR periods during spring and winter (44 % and 32 % of the annual GWR, respectively), values that are typical of other cold and humid climates. Snowpack evolution and soil frost were shown to be a key feature for GWR simulation in these environments. One of the contributions of the study was to show that the model sensitivity to its parameters was correlated with the average air temperature, with colder watersheds more sensitive to snow-related parameters than warmer watersheds. Interestingly, the results showed that the significant increase in precipitation and temperature since the early 1960s did not lead to significant changes in the annual GWR but resulted in increased runoff and evapotranspiration. In contrast to previous studies of past GWR trends in cold and humid climates, this work has shown that changes in past climatic conditions have not yet produced significant changes in annual GWR. Because of their relative ease of use, water budget models are a useful approach for scientists, modelers, and stakeholders alike to understand regional-scale groundwater renewal rates in cold and humid climates, especially if they can be easily adapted to specific study needs and environments.

A better understanding the effects of rainfall and evapotranspiration statistics on groundwater recharge (GR) requires long time series of these variables. However, long records of the relevant variables are scarce. To overcome this limitation, time series of rainfall and evapotranspiration are often synthesized using different methods. Here, we attempt to study the dependence of estimated GR on the synthesis methods used. We focus on regions with semi-arid climate conditions and soil types. For this purpose, we used longer than 40 year records of the daily rain and climate variables that are required to calculate the potential evapotranspiration (ETref), which were measured in two semi-arid locations.These locations, Beit Dagan and Shenmu, have aridity indices of 0.39 and 0.41, respectively, and similar seasonal and annual ETref rates (1370 and 1030 mm yr−1, respectively) but different seasonal rain distributions. Stochastic daily rain and ETref time series were synthesized according to the monthly empirical distributions. This synthesis method does not preserve the monthly and annual rain and ETref distributions. Therefore, we propose different correction methods to match the synthesized and measured time series' annual or monthly statistics. GR fluxes were calculated using the 1D Richards equation for four typical semi-arid soil types, and by prescribing the synthesized rain and ETref as atmospheric conditions. The estimated GR fluxes are sensitive to the synthesis method. However, the ratio between the GR and the total rain does not show the same sensitivity. The effects of the synthesis methods are shown to be the same for both locations, and correction of the monthly mean and SD of the synthesized time series results in the best agreement with independent estimates of the GR. These findings suggest that the assessment of GR under current and future climate conditions depends on the synthesis method used for rain and ETref.

Under the increasingly frequent extreme rainfall events, deep excavations are subjected to complex coupled effects of excavation-induced disturbance and rainfall infiltration, making it essential to clarify the deformation mechanisms of surrounding soils and retaining structures. In this study, a typical metro foundation pit in Zhengzhou was selected as the research object. By integrating field monitoring data with ABAQUS finite-element simulations, the deformation response and mechanical evolution of the pile–soil system under the combined influence of staged excavation and extreme rainfall infiltration were systematically investigated. The results indicate that rainfall infiltration leads to significant pore-water pressure accumulation, while the downward migration of the wetting front continuously reduces the effective stress and shear strength of the mid-to-deep soils. This process weakens the passive resistance at the pile toe and induces the downward movement of the primary deformation zone. The bending moment distribution of the retaining piles evolves from a “coexisting positive–negative moment” pattern to a “positive-moment dominant” mode, and the horizontal displacement at the pile toe changes from negative to positive, revealing a coupled mechanism involving deep-soil softening and arching loss. A mechanical chain of rainfall infiltration, pore-pressure evolution, stress redistribution, and pile–soil deformation is established to explain how extreme rainfall amplifies excavation-induced effects through dual pathways of mid-to-deep soil softening and accelerated seepage. Based on these findings, a prevention framework of source reduction, structural enhancement, and process control is proposed to improve the safety and resilience of deep excavations under extreme climatic conditions.