Groundwater Vulnerability Analysis in Karst Area Using Geographic Information System (GIS); Case Study of Putri Cave Area, Ogan Komering Ulu District, South Sumatra

The karst area is a zone of combination of easily dissolved rocks with well-developed secondary porosity. In line with the formation process, the karst region has a distinctive hydrological system, namely vertical drainage due to secondary porosity and removal of the rock, so that it has an abundant water content. During the dry season, water is found abundantly below the surface of the land, while during the rainy season, water is collected in the lakes. Abundant groundwater content in karst aquifers has the potential to be one of the natural resources. The karst aquifer has different hydrogeological and hydraulic characteristics from other aquifers. Characteristics of karst aquifers have a diffuse flow type that facilitates storage of water and flows slowly, so karst aquifers are very susceptible to pollution. Pollution can be caused by human activities, such as the disposal of industrial waste and excessive use of groundwater resulting in a decrease in the quality of groundwater. Research conducted around the Putri Cave karst area, Ogan Komering Ulu District, South Sumatra aims to determine the distribution zone and determine the level of vulnerability of groundwater. Determination of the distribution zone and groundwater vulnerability level using the field observation method and APLIS method (Altitude Pendiente Litologia Infiltrion preferencial and Suelo) which utilizes the Geographic Information System (GIS) with overlay analysis. Field observations include observing the appearance of rocks in a megascopic manner and the condition of the soil. The parameters used in the APLIS method to classify the level of vulnerability of groundwater are site elevation, slope, lithology / rock, infiltration zone, and soil. The results of the analysis show that the study area has a level of vulnerability in groundwater from low to high. Factors that influence differences in the level of vulnerability of groundwater in each region include geological conditions, slope, and type of aquifer