Hydrogeophysical estimation of groundwater potential using Dar-Zarrouk Parameters in Vikasnagar block of Dehradun district, Uttarakhand, India

This study estimates hydraulic parameters using geoelectrical data from twenty VES surveys, analyzed with 1-D inversion software. Four geoelectric layer patterns (HK and KH curves) revealed 7–8 strata with resistivity values ranging from 23.68 Ω-m to 257.53 Ω-m, with an average resistivity of 121.06 Ω-m. The three to seven geoelectric strata, which included alluvium, silt, worn or fractured phyllites, granite, quartzite, and sand, contained the major aquifer. Between 7.03 and 114.7 meters (average 65.08 meters) was the aquifer's depth; while between 17.22 and 68.13 meters (average 36.92 meters) was its thickness. The geoelectric data of hydraulic properties showed that the porosity ranged from 37.69% to 61.01% (average 48.43%), the transverse resistance ranged from 805.20 to 14236.81 Ωm² (average 4765.36 Ωm²), and the protective capacities ranged from 0.07 to 1.63 mhos (average 0.48 mhos). Transmissivity values varied from 37.51 to 799.26 m²/day (average 243.42 m²/day), anisotropy values from 0.27 to 2.79 (average 0.77), transverse resistivities from 10.59 Ω-m to 208.14 Ω-m (average 86.15 Ω-m), longitudinal resistivities from 19.74 Ω-m (average 280.98 Ω-m), and effective resistivity values from 23.68 to 257.53 Ω-m (average 130.83 Ω-m). Hydraulic conductivity varied from 2.18 to 20.18 m/day, with an average of 7.37 m/day. Aquifer hydraulic conductivity and transmissivity were evaluated using Dar-Zarrouk criteria, which separated the area into good and moderate groundwater production zones. When pumping test data is not available, the study shows how surface geophysics may be used to estimate aquifer hydraulic parameters.