Responses of groundwater system to water development in northern China

The increased demands on water resources in northern China have had a significant impact on groundwater systems in the last three to four decades, including reductions in groundwater recharge capacity and overall water quality. These changes limit the potential for groundwater uses in this area. This paper discusses the issues surrounding groundwater system use in the eight basins of northern China as water resources have been developed. The results demonstrate that the recharge zone has shifted from the piedmont to the agricultural area, and that the total recharge rate in the basins tended to decrease. This decrease in arid inland basins was mainly caused by both the excessive use of water in the watershed area and irrigated channel anti-seepage. In semi-arid basins, the decrease observed in the groundwater recharge rate is related to an overall reduction in precipitation and increasing river impoundment. In addition, intensive exploitation of groundwater resources has resulted in disturbances to the groundwater flow regime in arid and semi-arid inland basins. Arid inland basins demonstrated fast falling groundwater levels in the piedmont plains resulting in declines of spring flow rates and movement of spring sites to lower locations. In the semi-arid basins, i.e. the North China Plain and the Song-nen Plain, groundwater depression cones developed and intersected regional groundwater flow. The semi-arid basins of the North China Plain and the Song-nen Plain have experienced significant hydrochemical evolution of groundwater characterized by changing water type including increase of TDS and pollutants.

Recharge and vulnerability assessment of groundwater resources in North west India:Insights from isotope-geospatial modelling approach

Recent studies indicate dwindling groundwater quantity and quality of the largest regional aquifer system in North West India,raising concern over freshwater availability to about 182 million population residing in this region.Widespread agricultural activities have resulted severe groundwater pollution in this area,demanding a systematic vulnerability assessment for proactive measures.Conventional vulnerability assessment models encounter drawbacks due to subjectivity,complexity,data-prerequisites,and spatial-temporal constraints.This study incorporates isotopic information into a weighted-overlay framework to overcome the above-mentioned limitations and proposes a novel vulnerability assessment model.The isotope methodology provides crucial insights on groundwater recharge mechanisms(18O and 2H)and dynamics(3H)-often ignored in vulnerability assessment.Isotopic characterisation of precipitation helped in establishing Local Meteoric Water Line(LMWL)as well as inferring contrasting recharge mechanisms operating in different aquifers.Shallow aquifer(depth<60 m)showed significant evaporative signature with evaporation loss accounting up to 18.04%based on Rayleigh distillation equations.Inter-aquifer connections were apparent from Kernel Density Estimate(KDE)and isotope correlations.A weighted overlay isotope-geospatial model was developed combining 18O,3H,aquifer permeability,and water level data.The central and northern parts of study area fall under least(0.29%)and extremely(1.79%)vulnerable zones respectively,while majority of the study area fall under moderate(42.71%)and highly vulnerable zones(55.20%).Model validation was performed using groundwater NO3-concentration,which showed an overall accuracy up to 82%.Monte Carlo Simulation(MCS)was performed for sensitivity analysis and permeability was found to be the most sensitive input parameter,followed by 3H,18O,and water level.Comparing the vulnerability map with Land Use Land Cover(LULC)and population density maps helped in precisely identifying the high-risk sites,warranting a prompt attention.The model developed in this study integrates isotopic information with vulnerability assessment and resulted in model output with good accuracy,scientific basis,and widespread relevance,which highlights its crucial role in formulating proactive water resource management plans,especially in less explored data-scarce locations.

Zn-air batteries for electric vehicles

The increasingly serious environmental challenges have gradually aroused people's interest in electric vehicles.Over the last decade,governments and automakers have collaborated on the manufacturing of electric vehicles with high performance.Cutting-edge battery technologies are pivotal for the performance of electric vehicles.Zn-air batteries are considered as potential power batteries for electric vehicles due to their high capacity.Zn-air battery researches can be classified into three categories:primary batteries,mechanically rechargeable batteries,and chemically rechargeable batteries.The majority of current studies aim at developing and improving chemically rechargeable and mechanically rechargeable Zn-air batteries.Researchers have tried to use catalytic materials design and device design for Zn-air batteries to make it possible for their applications in electric vehicles.This review will highlight the state-of-the-art in primary batteries,mechanically rechargeable batteries,and chemically rechargeable batteries,revealing the prospects of Zn-air batteries for electric vehicles.