Groundwater level in the southern part of Surakarta city depicted from vertical electrical sounding

Abstract

In the last two decades, the city of Surakarta has shown significant population development, as well as in industry and tourism. This development must be accompanied by the provision of water resources for the lives of the population. As we know that in 2015 and 2019, there was a long dry season that resulted in a lack of water for residents and for the hotel industry, where most residents of Surakarta and the hotel industry are located in the southern part of the city of Surakarta. Therefore, the purpose of this study was to determine the level of groundwater aquifers in the south part of the city of Surakarta. We used the vertical electrical sounding (VES) method with the Schlumberger configuration at 10 survey locations. The current electrode interval in the Schlumberger configuration is from 1.5 meters up to 300 meters. With this stretch of electrode current, it is expected to reach target depth of up to 150 meters. Data processing uses the principle of non-linear optimization method which is to minimize errors from measurement data and models. We found that the depth of the groundwater aquifer was at 40 meters at S9 (shallowest), and at 80 meters at S5 (deepest). Then we compared this result with the survey in 2010 in the same location and same method. We found the lowering of the water table in some site surveys around 3 to 10 meters.