Assessing Groundwater Recharge Impacts in India's Bhuj Water Utility System

Thesis Abstract

The Bhuj water utility system faces increasing groundwater stress due to urban demand, climate variability, and limited surface recharge options, necessitating an evidence-based assessment of groundwater recharge impacts to inform sustainable management decisions. This study aims to quantify recharge rates, identify drivers of recharge changes, and evaluate the effectiveness of existing recharge interventions within Bhuj under contemporary hydrogeological and socio-economic contexts. Specific objectives include (i) estimating groundwater recharge using a combination of water balance, soil moisture accounting, and tracer-based approaches; (ii) assessing spatial and temporal variability in recharge across municipal, industrial, and peri-urban zones; (iii) linking recharge dynamics to rainfall variability, land-use change, and aquifer framework through multivariate statistical modelling; (iv) evaluating the performance of current artificial recharge structures and natural recharge pathways; and (v) developing a decision-support framework to optimize recharge enhancement under climate and population growth scenarios. The methodology adopts a mixed-methods design integrating quantitative hydrogeochemical data, hydrological modelling, and qualitative stakeholder insights. The study population comprises groundwater abstraction points, recharge structures, and aquifer response indicators within the Bhuj Municipal Corporation jurisdiction and surrounding rural communities (n ? 150 observation wells, 25 recharge installations). A stratified random sampling approach selects 60 observation wells for tracer and isotopic analyses (stable isotopes 18O, 2H; dissolved noble gases) and 15 monitoring sites for groundwater level and conductivity logging over two rainfall seasons. Data collection instruments include lysimeters, borehole geophysical logs,?water and groundwater sampling protocols, rainfall gauges, soil moisture probes, and semi-structured interviews with utility engineers, policymakers, and farmers. Validity and reliability are ensured through calibration of lysimeters, cross-validation with existing monitor networks, inter-laboratory checks for isotope analyses, and pilot testing of interview guides. Recharge estimation employs (i) a water balance approach incorporating rainfall, evapotranspiration, runoff, and abstraction data to derive net recharge; (ii) numerical groundwater flow modelling using MODFLOW to simulate aquifer response under baseline and scenario conditions; (iii) tracer-based recharge delineation to distinguish recent recharge fluxes from older components; and (iv) regression-based sensitivity analysis to identify key drivers of recharge variability. Analytical techniques include multiple linear regression, time-series decomposition, ANOVA to compare recharge across zones, and spatial interpolation with ordinary kriging. Theoretical framing builds on the Water-Energy-Food Nexus and the Cyclical Recharge Theory, with the conceptual framework integrating climate variability, land-use change, anthropogenic pumping, and recharge pathways. The study explicitly references the theories of groundwater governance and resilience theory to interpret policy implications. Key expected findings include (i) quantification of annual recharge rates in Bhuj with an estimated mean of 12–20 mm year?1 in high-recharge zones and 4–8 mm year?1 in degraded areas, (ii) identification of rainfall, aquifer storage, and surface cover as primary recharge drivers, (iii) evidence of limited artificial recharge effectiveness due to hydrochemical stratification and transient pumping drawdown, and (iv) spatially explicit maps highlighting recharge hotspots and deficits correlating with land-use patterns and groundwater extraction intensity. The integration of tracer data with MODFLOW simulations is anticipated to reveal distinct aquifer responses to monsoon variability and urban expansion, informing targeted recharge enhancements. The study contributes to knowledge by delivering a scalable, policy-relevant recharge assessment framework tailored to arid and semi-arid urban systems, combining hydrological modelling, tracer analysis, and governance considerations to bolster groundwater resilience. It advances methodological integration for semi-arid contexts and offers transferable insights for similar coastal-peninsular water utilities facing climate stress and rapid urbanization. The main conclusion will emphasize the relative effectiveness of current recharge strategies and propose an evidence-based mix of nature-based solutions, managed aquifer recharge design improvements, and governance reforms. Recommendations include prioritizing recharge basins with validated positive response to interventions, integrating recharge assessment into utility planning cycles, establishing continuous monitoring with industry-standard QA/QC protocols, and adopting a participatory decision framework that aligns stakeholder incentives with groundwater sustainability objectives.