Numerical investigations on the reclaimable aquifer recharge from injection wells: a case study

Groundwater management has emerged as an utmost necessity with the declining groundwater levels due to excessive extraction rates. The recharge–extraction operations play an essential role within the backdrop of artificial recharge of the aquifers with injection wells. Analysis of various management scenarios was done by numerical modeling. Visual MODFLOW Flex models were constructed to simulate the Indian Institute of Technology Madras campus’s aquifer system. The MODFLOW groundwater flow models were coupled by the particle tracing, using the MODPATH module, thereby delineating the pumping well capture zones and aquifer zones attributed by recharge wells. The superimposition of both the catered zones yielded the convergence area for assessing pumped recharge water recovery. The analyzed metrics were presented as percentages based on the aquifer volumes coinciding within the convergence areas. In the present paper, a straightforward concept of convergence zone was introduced, and their areal and volumetric contributions were computed to study the volume of recharge water reclaimed upon extraction. The results from different models revealed an average of 11.74% of the total recharged aquifer volume, and 35.40% of the pumped aquifer volume was reclaimable. The results also facilitated better communication to the stakeholders, implying the benefactors of the recharge operations and thereby aiding proper emplacement of injection wells to aid policymaking and accomplish set objectives.