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

作　　者：Annadasankar Roy Sitangshu Chatterjee Uday Kumar Sinha Anil Kumar Jain Hemant Mohokar Ajay Jaryal Tirumalesh Keesari Harish Jagat Pant 

机构地区：[1]Isotope and Radiation Application Division,Bhabha Atomic Research Centre,Trombay,Mumbai–400085,India [2]Homi Bhabha National Institute,Mumbai 400094,India [3]Central Ground Water Board,Ahmedabad,Gujarat,India

出　　处：《Geoscience Frontiers》2024年第1期247-262,共16页地学前缘（英文版）

摘　　要：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 s

关 键 词：Agricultural pollution Data scarcity Recharge mechanism Rayleigh distillation Isotope-geospatial model Vulnerability assessment 

分 类 号：P641.8[天文地球—地质矿产勘探]