A study conducted by the geology department of Savitribai Phule Pune University (SPPU) has revealed a significant rise in groundwater levels of approximately 15 to 30 centimeters in water-stressed villages across 13 talukas of Pune district. This rise in groundwater levels was observed in areas where trench-cum-recharge shaft structures were constructed to combat drinking water scarcity.
The research report, titled ‘Impact Assessment of Trench-cum-Recharge Shaft Structures constructed in water-stressed villages across 13 talukas of Pune,’ was submitted to the Pune Zilla Parishad (ZP). The study focused on assessing the effectiveness of these structures in replenishing groundwater sources.
Professor Bhavana Umrikar, an associate professor of Geology at SPPU, emphasized the importance of rainwater harvesting and efficient water resource management, especially in rural areas of Maharashtra that rely heavily on groundwater for drinking water.
Trench-cum-recharge shafts, which were constructed in 103 villages across Pune district, have proven to be an efficient and cost-effective technique for recharging unconfined aquifers overlain by poorly permeable strata. These structures consist of a recharge shaft placed in a recharge pit surrounding the filter media. The shaft has a diameter of 0.5 meters and a depth ranging from 25 to 30 meters. These structures are strategically placed where the shallow aquifer is located or where the upper layer of soil is alluvial or less permeable.
The study’s findings indicate that in the first year of assessment, there has been a notable increase in groundwater levels, but further assessment over one or two more hydrological cycles is recommended to confirm the long-term impact. Regular maintenance of the trench-cum-recharge shaft structures is also crucial to ensure maximum benefits in terms of elevated aquifer recharge and a consistent supply of drinking water in these villages.
Professor Umrikar stressed the importance of continuous monitoring, including rainfall analysis, groundwater level trends, and the number and duration of tanker water supply in water-stressed villages, to quantify the role of recharge shafts in mitigating water scarcity.
The Pune ZP, to which the research report has been submitted, recognizes the importance of impact assessment studies for recharge structures and the need to generate before-and-after scenarios to understand changes in water availability. These studies are essential for achieving the goal of providing safe drinking water throughout the year and reducing dependence on water tankers.
In addition to the assessment of groundwater levels, the study also involves the comparison of current groundwater levels with data from the previous hydrological year and trend analysis. Hydrographs generated at representative locations have been studied to analyze recent trends and increased groundwater levels, especially during severe summer months.
