In the present study, a total of sixty groundwater samples, twenty each for the pre-monsoon, monsoon and post monsoon seasons of 2018, were collected from selected locations in the Mewat district of Haryana, India. Electrical conductivity (EC) was measured at the site and total dissolved solids (TDS) were estimated. Samples were analysed for anions (chloride, sulphate, and bicarbonate) and cations (calcium, potassium, magnesium, and sodium). Multiple regression analysis was performed to analyse the data and report the dominant ions. Piper trilinear diagram and Gibbs plots were used to find out the water type and the factors controlling the chemistry of the groundwater, respectively. The saturation index of CaCO₃, CaSO₄ and NaCl was determined, using the PHREEQC MODEL. Sodium and calcium among cations, and chloride among the anions, had the highest degree of affinity and strong significance for all three seasons. The calcium–chloride water type dominated for all three seasons and Gibbs plot depicted that most of the Na⁺/Na⁺ + Ca²⁺ and Cl⁻/Cl⁻ + HCO₃⁻ ratios show the weathering of rocks to form minerals as the major reason behind the ionic chemistry of the groundwater. The highest level of dissolution is encountered in the case of NaCl, followed by CaSO₄, whereas CaCO₃ depicts precipitation. The geochemical aspects of weathering, evaporation and ion exchange are the major processes responsible for high salinity, and anthropogenic activities are leading to its expansion. The findings from this study will be useful in management and remediation of groundwater salinity of the region.

Groundwater depletion in northern India, particularly in the intensively cultivated alluvial aquifers of the Indian Ganga Basin (IGB), poses a growing threat to agricultural sustainability and water security. This work aims to present a predictive assessment of groundwater balance and long-term resource sustainability in the IGB using a high-resolution numerical modelling approach. A four-layer aquifer model was developed at a 500-meter spatial resolution to simulate groundwater dynamics from 1997 to 2023. The model integrates refined estimates of recharge, evapotranspiration, groundwater abstraction, and river-aquifer interactions, and is implemented using MODFLOW 6 with a control-volume finite difference scheme. Uncertainties in the estimation of model parameters and resulting uncertainty in water balance components were quantified using the iterative ensemble simulation approach. The model was applied to assess groundwater use under varying climate and abstraction scenarios. Preliminary results showed historical storage depletion consistent with observed groundwater levels and regional trends identified using GRACE-based remote sensing approaches. Areas of significant storage depletion also overlapped with districts that have high estimated groundwater extraction. They also highlight spatial and temporal patterns of groundwater stress, identify critical zones of imbalance, and demonstrate the model’s utility in evaluating policy interventions. This modelling framework provides a robust tool for guiding sustainable groundwater management strategies at regional and sub-basin scales.