GEOLOGY AND INTERACTION BETWEEN GROUNDWATER-SURFACE WATER OF CITARUM WATERSHED IN MAJALAYA-IBUN DISTRICTS, BANDUNG REGENCY, WEST JAVA PROVINC

• Main Author: Anatra Rahmana Effendi, Fabio
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/47327
• Institution: Institut Teknologi Bandung

The geologic and hydrogeologic studies were conducted in Majalaya and Ibun Districts, Bandung Regency, West Java Province. The purpose of the study is to understand geological condition and to analyze hydrogeological condition of the research area with the objective to know the interaction between groundwater and surface water both qualitatively and quantitatively. The methods used in this research are geological and hydrogeological fieldworks, weather data analysis, landuse data analysis, soil type data analysis, stream stage data analysis, hydrologic and groundwater modelling. The research area can be divided into three geomorphological units, i.e: Majalaya Intervolcanic Plains, Cilutung Volcanic Footslopes, and Cones of Jawa-Pangkalan Volcanoes. Stratigraphically, from older to younger, the research area consists of Pangkalan Volcanic Complex comprising Lava Pangkalan Volcano Unit (Pl), Cilutung Volcanic Complex comprising Breccia Pyroclastic Flow Cilutung Volcano Unit (Ca) and Lava Cilutung Volcano Unit (Cl), and Alluvial Deposits (Md). Geological structure developed in the research area is Cikaro Dextral Reverse Slip Fault. The interaction between groundwater and surface water in the research area is generally effluent, but in the downstream it is influent. The result of the modelling using SWAT-MODFLOW shows that in the dry season, the highest value of groundwater surface water exchange rates is -1350 m3/day (effluent) while the lowest is -4331 m3/day (effluent). Meanwhile, in the wet season, the highest is -276 m3/day (effluent) and the lowest is -9451 m3/day (effluent). Based on physical parameters and pH data from 39 measurement points, there are two points recognized as not fulfilling pH criteria for drinkingwater and cleanwater usage based on PERMENKES.