Geophysical assessment of open dumpsite nearby Khamis Mushait industrial zone, Southwestern Saudi Arabia

Abstract Vertical electrical soundings, seismic refraction tomography, and ground magnetic measurements were taken or conducted close to an open dumpsite near Khamis Mushait, southwestern Saudi Arabia, which is characterized by shallow groundwater conditions. Structurally, intersected series of north- to northwest-trending faults affect the area. A new urban expansion and the Khamis Mushait industrial zone are close to the open dumpsite. This study evaluates the potential for leachate intrusion into groundwater aquifers. The results of electrical soundings reveal four geoelectric units: the topsoil, weathered layer, partly weathered/fractured basement, and fresh basement bedrock. At the dumpsite, relatively low resistivity values that are less than 30 Ωm characterize the topsoil, weathered layer, and partly weathered/fractured basement because of conductive leachate from the dumpsite. Besides, the results of ground magnetic data indicate that the deformation of varying intensities affects the dumpsite area, resulting in fractures developing in the N–S, NE–SW, NW–SE, and, to a lesser extent, E–W directions. Moreover, geoseismic tomographic models illustrate a low P-wave velocity zone corresponding to a low resistivity zone, and a NE–SW fault was identified from geoseismic cross-sections. Finally, these fractures and faults could become contaminant pathways for shallow aquifers around the dumpsite. To minimize the impact of such leachate, from a dumpsite, on groundwater quality and the environment in general, the dumpsite must be properly designed, constructed, and managed using engineering principles.