© 2022 Gravitasi is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License Gravitasi Vol. 21 No. 1 (June 2022) 35-43 Modeling Analysis of Seepage Potential Based on Rock Resistivity Value in Geoelectric Method at Pamukkulu Dam Rohaya Langkoke *) Department of Geological Engineering, Engineering Faculty, Hasanuddin University Information Abstract Article history: Received: 23 September 2022 Accepted: 1 October 2022 Published: 23 December 2022 Keywords: Dam Geophysical Methods Geoelectric Resistivity Administratively, the research area is the jurisdiction of the Pamukkulu Dam construction project of PT. Wijaya Karya in Kale Komara Village, Polongbangkeng Utara District, Takalar Regency, South Sulawesi Province. The purpose of this study is to determine the condition of the subsurface rock and the pattern and direction of seepage in the construction of the dam. The method used is the geophysical method with geoelectric measurements. The condition of the rocks below the surface in the study area can be interpreted based on the results of observations and resistivity tests where breccia and basalt rock types are on a resistivity scale of >= 100 ohm.m. The value below 100 ohm.m is categorized as a layer of soil or weathered. The result of the interpretation of the seepage modeling is that seepage patterns are found that resemble folds in the form of blue, and also from these patterns the seepage direction is found. From the results of modeling with the voxler application, the direction of seepage in the study area starts from the East and Northeast and leads predominantly to the Northwest and Southwest. *) e-mail: rlangkoke@gmail.com DOI: 10.22487/gravitasi.v21i1.16035 1. INTRODUCTION Takalar is one of the districts in the province of South Sulawesi which has a diversity of morphologies it forms. With the shape of the land surface is relatively flat, wavy to the hills. Most of the Takalar Regency area is plains and coastal areas [1]. The unavailability of raw water in several areas is caused by the wavy topography and sub-optimal water control, causing problems that must be handled appropriately. One of the solutions to ensure the availability of raw water, as well as equal distribution of irrigation channels, is the construction of dams. In order to support the planning of dam construction, engineering geological investigation is required. Damming a river means changing the natural properties of the river, so that there are both positive and negative technical impacts, as well as influences, problems and constraints both on the dam building and the surrounding environment [2]. Engineering geological investigations need to be carried out to determine the geological conditions and engineering characteristics of the dam construction plan area. The foundation of a dam must rest on rocks that have good carrying capacity so that the dam building will not experience deformation (change in position) due to technical factors so that the dam will have a long life [3,4]. Administratively the research area is included in Kale Ko'mara Village, North Polombangkeng, Takalar Regency, South Sulawesi Province, based on the astronomical location of the research location at 5°23'54" S and 119°35'34"E. It can be seen in Figure 1 which explains the research area. 2. RESEARCH METHOD The research method is structured as a reference in conducting research so that the process can run scientifically, systematically, and precisely. In this study, 4 stages were included, namely the preparation stage, data collection stage, data processing stage, data analysis and interpretation, and report preparation stage. In detail, these stages are as follows: 1. The preparation stage consists of administration, literature study, field equipment, and determination of geoelectric survey points. 2. The field observation stage includes field surveys [5] and installation of geoelectric devices, as well as retrieval of resistivity data [6,7]. 3. The data processing stage consists of field resistivity data which will be processed on Res2NDIV and Voxler software [8]. 4. The stage of making a research report The research methods and stages can be seen in Figure 2 which explains the flow of the research stages. 3. REGIONAL GEOLOGY OF RESEARCH AREA The regional geology of the research area is in the sheets of the regional geology of the Ujung Pandang, Benteng, and Sinjai. This area includes the Districts of Maros, Sungguminasa, Takalar, Jeneponto, Benteng, Bulukumba, Sinjai and Salayar; including the Province of South Sulawesi. Gravitasi Journal available at: https://bestjournal.untad.ac.id/index.php/GravitasiFisika e-ISSN: 2654-4318 p-ISSN: 1412-2375