Subsurface Identification using Resistivity Method for Infrastructure Planning in Benowo Area, Surabaya City

Abstract

Subsurface rock identification in infrastructure construction is important to get the information in planning and monitoring the rock carrying capacity and groundwater systems for infrastructure construction. To get the subsurface condition information that are relatively shallow with detailed results, Resistivity method with Wenner configuration is used. Research is in Benowo area, where dominated by pond area. This research used 5 Resistivity lines, which are divided into 2 locations separated by distance of about 2400 meters as Z1 and Z2 areas. For the subsurface resistivity section at Z1 area there are 2 lines, while at Z2 area there are 3 lines. It is known at Z1 area, top layer is topsoil (2.26-33.00 Ωm) and the bottom layer was identified as clay (0.30-2.26 Ωm). At Z2, top layer being topsoil (0.306-0.708 Ωm), followed by clay layer (0.100-0.306 Ωm), and the sand layer (0.231-0.535 Ωm) in the bottom of resistivity model. Groundwater system shows topsoil acts as a vadose zone, clay layer acts as an aquiclude and the sand layer acts as an unconfined aquifer. Saturated water influences the low resistivity value measurement related to the environmental condition dominated by pond area, beside measurements in rainy season are also suspected to be the cause of low resistivity measured. To be applied infrastructure development in the Benowo area need further treatment activity like soil and/or rock pavement to support infrastructure safety. This research result is related to geotechnical aspects like rock coring, pavement, and optimum architectural design can be an alternative for further research.