Abstract The Loess Plateau of China (LPC) is suffering from the impacts overexploitation groundwater, leading to a decline in regional water table. This compounded by relatively recent large‐scale transformation land use, which may impact groundwater recharge and threaten future quality intensive nitrogen fertilizer application. Understanding unsaturated flow nitrate travel time deep vadose zone crucial for sustainable management LPC system. We develop here regional‐scale model that exploits...

Abstract. Nitrate is considered the most common non-point pollutant in groundwater. It often attributed to agricultural management, when excess application of nitrogen fertilizer leaches below root zone and eventually transported as nitrate through unsaturated water table. A lag time years decades between processes occurring their final imprint on groundwater quality prevents proper decision-making land use groundwater-resource management. This study implemented vadose-zone monitoring system...

Groundwater recharge is primarily influenced by land use and climate. Nevertheless, it the flow transport processes that take place in vadose zone ultimately control quantity quality of groundwater replenishment. Vadose monitoring systems (VMSs) were implemented under agricultural fields. The VMSs provided continuous information on both temporal variation water content chemical composition sediment pore at multiple depths deep (∼20 m). Models for vertical unsaturated chloride calibrated to...

Abstract. Groundwater is one of the most essential natural resources and affected by climate variability. However, our understanding effects on groundwater recharge (R), particularly in dry regions, limited. Future projections suggest changes many statistical characteristics potential evapotranspiration (Ep) rainfall that dictate R. To better understand relationship between statistics R, we separately considered to mean, standard deviation, extreme Ep precipitation (P). We simulated R under...

Climate change is expected to raise groundwater temperatures, affecting more than 100 million people living in areas where temperatures exceed national drinking water standards. However, many of these projections are based on models rather observations. As countries implement continuous monitoring programs for the sustainable management systems, analyzing trends level and quality data related climate becoming feasible. Therefore, goal this study was utilize a 30-year record collected from...

Nitrate pollution of groundwater is often attributed to excess fertilisation in agriculture. Low quality water, enriched by nitrate and other pollutants percolates down from the root zone through unsaturated water table. Accordingly, vadose holds footprint all possible events occurring at land surface before imprint arrives groundwater. Here we present a study were detailed long-term monitoring reveals potential various representative agricultural setups over island Malta. Malta semi-arid...

As aridity increases, the importance of focused groundwater recharge becomes more significant. It is well-recognized that in arid areas primarily occurs during flash floods ephemeral streams. However, previous studies suggest diffuse recharge—spatially distributed replenishment from precipitation or irrigation—may also play a substantial role aquifers recharge. This study aims to quantify contribution through unsaturated fractured Chalk under conditions Negev Desert.Three...

Abstract Switching crop type and consequently changing irrigation fertilization regimes lead to alterations in deep percolation solute concentrations of pore water. Herein, observations from the vadose zone model simulations demonstrate changes water, chloride, nitrate fluxes under a commercial greenhouse following change tomato lettuce cropping. The site, located above phreatic aquifer, was monitored for 5 years. A vadose‐zone monitoring system implemented provided continuous data on both...

Abstract Understanding nitrate migration through the deep vadose zone is essential for aquifer vulnerability assessments. The effect of variability physical properties on transport has been scarcely explored. Recently, storage profiles were determined in Loess Plateau China. Using these observations along with measured soil properties, this study investigates loess vertical heterogeneity water movement and zone. Models different complexity established calibrated. First, a simple piston flow...

Abstract. Soil aquifer treatment (SAT) is a tertiary process for wastewater treatment, where the infiltrates through thick vadose zone purification and storage in underneath aquifer. SAT infiltration basins are typically flooded intermittently, while maintaining fixed ratio between wetting drying stages. However, exhibit different physical chemical properties, limiting generalization of operation to attain optimal efficiency. Since frequent sampling soil pore water verify SAT's...

Abstract. A better understanding the effects of rainfall and evapotranspiration statistics on groundwater recharge (GR) requires long time series these variables. However, records relevant variables are scarce. To overcome this limitation, often synthesized using different methods. Here, we attempt to study dependence estimated GR synthesis methods used. We focus regions with semi-arid climate conditions soil types. For purpose, used longer than 40 year daily rain that required calculate...

Abstract Extensive nitrogen loads at the soil surface exceed plant uptake and biochemical capacity, therefore lead to accumulation in deep vadose zone. Studies have shown that stored zone can eventually reach water table affect quality of groundwater resources. Recently, global scale models been implemented quantify nitrate storage travel time These are simplistic relatively easy implement facilitate analysis considered transport processes a regional with no further requirements. However,...

Abstract Vegetation changes that are driven by soil conservation measures significantly affect subsurface water flow patterns and status. Much research on consumption sustainability of newly introduced vegetation types at the plot scale has been done in Loess Plateau China (LPC), typically using local measurements content (SWC). However, information collected cannot readily be up‐scaled. Geophysical methods such as electromagnetic induction (EMI) offer large spatial coverage and, therefore,...

In-situ bioremediation techniques are cost-effective, environmentally friendly, and sustainable. This study examined a large-scale in-situ treatment of deep (40m) unsaturated zone local groundwater system heavily contaminated with perchlorate other co-contaminants, including nitrate, chlorate, different explosives. The shows that the upper section was used as bioreactor for treating groundwater. based on cyclic process included pumping groundwater, adding an essential electron donor,...

Abstract. Groundwater is one of the most essential natural resources and affected by climate variability. However, our understanding effects on groundwater recharge (GR), particularly in dry regions, limited. Future projections suggest changes many statistical characteristics potential evapotranspiration (ETref) rainfall that dictates GR. To better understand relationship between statistics GR, we separately considered to mean, STD, extreme ETref rainfall. We simulated GR under different...