Effect of seasonal variation in dielectric properties of groundwater from Vadodara region

Groundwater samples were collected during different months from the same site from Vadodara district of Gujarat state. The complex permittivity of the water samples were precisely determined over the frequency span 20 Hz to 2 MHz. Complex permittivity spectral data were converted into complex impedance formalism. Obtained results were analysed to get information of seasonal variation in groundwater quality. Dielectric constant for all samples is found to decrease linearly and rapidly with increase in frequency up to about 4 kHz, after which it decreases slowly and achieves static value approximately 78, near 2 MHz for all water samples. Dielectric loss for the water sample collected in monsoon season (August) is the highest, which shows the presence of ions dissolved from the soil in rain water. DC resistance values, determined from the complex impedance plane plot (Z′’ vs. Z″), suggested an increase in the conductivity of the water samples collected near the end of monsoon season, due to the dissolved minerals and salts from soil. The calculated values of ε′’/ε′’DW and ε″/ε″DW ratio for the water sample of August’18 show a relatively large increase during the post-monsoon month of August’18, above 2 kHz, as compared to other months.