The interaction between groundwater and urban environments is a growing concern for many rapidly urbanizing cities around the world, affecting both recharge and flow, since impervious surfaces reduce infiltration by increasing runoff, whereas over-abstraction leads to groundwater depletion and land subsidence. Additionally, industrial pollution and wastewater disposal contribute to contamination, impacting groundwater quality. The effective governance of groundwater within such urban locales necessitates a profound understanding of the hydrogeological context, coupled with robust tools for projecting fluctuations in groundwater levels and changes in water quality over time. We quantified urban groundwater recharge in Guwahati city, Assam, India, using the rainfall infiltration method and a numerical approach. Precipitation, evapotranspiration, runoff, and recharge from surface water bodies were considered the components of natural recharge, while leakages from water supply, domestic wastewater, and industrial wastewater were considered the components of urban recharge. The cumulative total of natural and urban components determines the actual groundwater recharge. The estimated natural groundwater recharge is 11.1 MCM/yr, whereas the urban groundwater recharge is 44.74 MCM/yr. Leakages from urban infrastructure resulted in significantly higher groundwater recharge than from natural inputs. Steady declines in groundwater recharge were observed from estimates taken at various time points over the past two decades, suggesting the need for prompt action to improve groundwater sustainability.

This study investigated the hydrogeological characteristics and groundwater dynamics in the shallow aquifer zones of inner Guwahati city, Assam, India. Sixteen dug wells spread across the city, specifically used for domestic purposes, were selected for this study. Additionally, ten wells were selected for trend analysis. The borehole lithology reveals predominant compositions of clay, sand, and granules, with thin clay cappings indicating significant groundwater potential. Depth-to-water level analysis revealed varying water levels across the study area, with shallow levels in the northern and western regions and gradual deepening toward the eastern and southern parts. The groundwater flow directions show nonuniform patterns and reflect the influence of topography and domestic pumping in urban residential zones. The general groundwater flow direction is toward the Brahmaputra River. Trends in groundwater level, assessed using the Mann–Kendall test and Sen’s slope, suggest both falling and rising trends across different locations, indicating complex groundwater dynamics influenced by factors such as recharge, extraction, and topography. However, the long-term rainfall data indicate no significant trend over the studied period, suggesting limited natural influence on groundwater level trends. These findings may contribute to a comprehensive understanding of groundwater dynamics in the study area and are essential for sustainable water resource management and mitigation of groundwater depletion risks.

The Journal of Environmental Science, Health & Sustainability is dedicating this issue (Vol. 2 & No. 1) to the life and legacy of Prof. (Dr.) Chandan Mahanta. Dr. Mahanta was an erudite scholar, an educator, an administrator, and above all, a name deeply etched in the history of the Indian Institute of Technology (IIT) Guwahati, India. A staunch environmentalist, he had left an indelible mark on the academic and scientific community.