One of the early high-frequency groundwater monitoring studies in Central India: aquifer response and stress mapping

Groundwater dynamics in basaltic hard-rock terrains are highly heterogeneous and remain poorly understood due to reliance on low-frequency monitoring. This study investigates aquifer stress–response behaviour in the over-exploited basaltic aquifers of Ratlam District, Central India, using high-frequency groundwater level data (four readings per day, aggregated to daily values) from 15 monitoring wells during 2023–2025. Groundwater abstraction in the district exceeds annual recharge (~ 130%), with intensified post-monsoon pumping during the rabi season. The high-frequency records capture short-duration monsoon recharge events, peak depletion rates, and prolonged recession during the monitoring period, driven by intensive pumping, including episodes of rapid groundwater level decline. Pearson’s correlation and Ward’s hierarchical clustering identify five hydrodynamically distinct response groups that align with geomorphology and regional hydraulic gradients rather than with well depth alone. Semi-confined areas show stronger seasonal declines, while unconfined uplands exhibit broader recovery and gradual recession. Inter-well similarity is stronger at seasonal–annual scales, reflecting primary monsoon recharge and abstraction, with similar responses observed across both shallow and deeper systems. These findings demonstrate that high-frequency groundwater monitoring can resolve spatial patterns of recharge- and abstraction-dominated behaviour in hard-rock aquifers. The study introduces a preliminary similarity-based approach for interpreting spatial variability in groundwater response, improving groundwater assessment and management in stressed basaltic terrains.