Resistivity and Seismic Refraction for Solving Groundwater-Related Problems: A Case Study from North Oman

Geophysical methods are very widely used for groundwater exploration and characterization. In Sultanate Oman, with the increasing demand for groundwater, geophysical methods are increasingly involved in exploration activities and solving problems relevant to this vital natural resource. In this study, seismic and resistivity methods were used to solve problems related to groundwater in Bidbid, Northern Oman. Falaj Mazra in Bidbid, the ancient irrigation channel, receives surface water from Wadi Samail’s water running from the base flow when the wadi is dry. Four pipelines were installed and buried over the wadi channel, parallel to its course. After several years of flow, the falaj has dried up. Geophysical methods have been invoked to investigate whether the pipelines’ influence on the falaj system caused its dryness. Resistivity and seismic refraction have revealed that the water table has dropped below the bottom of the falaj. Landsat images collected over the area have shown a significant increase in agricultural activities during the past decade. Consequently, the actions led to a considerable rise in groundwater exploitation. In addition, demographic statistics over the past decade also inferred that the overexploitation of groundwater by the increasing population has contributed to the decline of groundwater reserves and water table. In conclusion, based on the results from seismic and resistivity, the falaj dryness is attributed to the water table level drop caused by the increasing population and its associated agricultural activities.