Understanding area specific recharge process from Vadoze zone resistivity variations - a case study in basalt watershed, Ujjain district, Madhya Pradesh

Spatial variability in parameters used in groundwater resource estimation and budgeting over an area always compromised with averaging and distribution. Among the parameters, the natural recharge spatial variability found to influence critically in resource assessment. To understand the spatial variability in principal recharge component, an attempt is made to relate the vadoze zone characteristics by integrating results of natural recharge, injected tritium tracer studies, infiltration and electrical resistivity tomography over black soil covered basaltic Ghatiya watershed in Ujjain district, Madhya Pradesh. Analysis of recharge function at three sites representing upper (recharge area), middle and lower (discharge parts) is found to be a function of vadoze zone resistivity characteristics and an exponential function of infiltration rate. The relationship may help in getting the dependency in spatial distribution of recharge with limited spot recharge measurements and resistivity characteristics of vadoze zone of intervening areas and infiltration indices.