Seasonal dynamics of groundwater irrigation restrictions in semi-arid India: Carbonate alkalinity and spatial uncertainty

This dataset supports an unpublished research manuscript investigating seasonal changes in groundwater hydrochemistry and irrigation-water restrictions in semi-arid hard-rock aquifers of Telangana, India. The study includes 149 geographically matched groundwater monitoring locations distributed across six watersheds, with 298 observations representing pre- and post-monsoon sampling periods. The hydrochemical assessment considers eight directly measured variables: pH, electrical conductivity (EC), calcium, magnesium, sodium, combined carbonate-bicarbonate alkalinity, chloride and boron. Two derived irrigation-quality indicators, sodium adsorption ratio (SAR) and residual sodium carbonate (RSC), are also evaluated. Irrigation-related restrictions are assessed using EC salinity, combined EC-SAR infiltration criteria, RSC alkalinity and boron toxicity, integrated through a most-restrictive-indicator classification. The associated study uses paired seasonal comparisons, principal component analysis, spatially blocked interpolation cross-validation and deterministic classification-sensitivity analysis. The analysis identifies changes in groundwater irrigation restrictions between the two sampling periods. Severe integrated restriction increased from 41.6% of monitored sites before the monsoon to 53.7% afterwards, with RSC representing the dominant severe restriction criterion. The dataset is intended to support transparent documentation, reproducibility and further investigation of seasonal groundwater-quality variability and irrigation-water management. Users should distinguish observed groundwater measurements from modelled spatial estimates and should not interpret groundwater restriction classes as direct measurements of crop yield or soil degradation. This repository record describes supporting research data and does not represent publication of the associated manuscript in a peer-reviewed journal.