Hydraulic conductivity estimation using direct current (DC) sounding data: a case study in East Nile Delta, Egypt

Automated vertical electrical sounding (VES) inversion schemes were applied for hydrogeological characterisation at a semi-arid area in the southeastern part of the East Nile Delta, Egypt. The apparent resistivity measurements were integrated with borehole, hydrogeological and structural information for a better description of the subsurface conditions. The final results were presented in the form of cross-sections, maps and 3D diagrams to visualise the geological and hydrogeological situations. The resistivity values derived from the VES data were used to predict the hydraulic conductivity (K) values by using two empirical relations, which depend on the direct relation between K and the aquifer transverse resistance (T) and the power relation between K and the aquifer resistivity (ρ). The estimated values were compared with the observed K values obtained from the pumping tests. The power law relation produces more reliable predicted K values that show a good correlation with the data compiled for the hydraulic gradient of the main Pleistocene aquifer in the East Nile Delta. The results also indicate that the joint use of an automated 1D interpretation algorithm and the power law empirical relationship constitute a valuable tool to characterise the hydrogeophysical properties of aquifers in the study area.