HYDROGEOLOGY STUDY AND GROUNDWATER PUMPING SIMULATION IN <BR />RUMBIA AREA, BUTON, SOUTH EAST SULAWESI

• Main Author: KUSBAGYO, JOHANES
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/2115
• Institution: Institut Teknologi Bandung

Research area which is located in Aneka Marga and Lombakasih villages, Rumbia area, Kabupaten Buton, South East Sulawesi Province. The research location is rice field dependent on rain which is one time harvesting, it population is people relocation from Java (transmigrant). Geology of the research area is alluvium deposit of coastal swamp which consist of mud, clay, sand, gravel and pebble and this forms unconfined shallow aquifer. Confined aquifer is located under alluvium later and its name is Langkowala Formation, this layer consist of gravel, pebble, sand and sandy clay. Clay iayer is located alternatingly with aquifer layer. In this area, water well have been installed 22 wells, with depth around 68 m to 125 m and diameter of well is 8 inch to 6 inch, all wells used to simulation model. The research purposes are hydrogeology study and groundwater drawdown change predict which caused by pumping at optimum debit of each production water well, also drawdown change which caused by pumping at maximum debit of each production water well, until the position of safety drawdown been known. To predict the drawdown, simulation done using mathematics approach method which solved with finite difference method. To make its model, the research area divide to 30 node of discrete points arranged in a grid pattern with same size, the distance of grids are Ax = Ay = 500 m. Personal Computer used to fast and support process and valid counting. Test of program validity done by entering field data to program until produce drawdown on each well. Then the drawdown from simulation result compared with drawdown from field measurement. Transmissivity from field measurement is changed and calibrated, then the drawdown from simulation model result will be same with drawdown from field measurement ( from pumping test). Simulation done with pump out all of the wells in the research area using optimum debit and maximum debit of each well. Pumping simulation at optimum debit of each well around 5.50 I/sec. (BTN-04) to 40.00 I/sec. (BTN-03), the drawdown around 11.00 m (BTN-04) to 28.00 m (BTN-06) under ground surface. Pumping simulation at maximum debit of each well around 10.00 I/sec. (BTN-04) to 66.00 I/sec. (BTN-03), the drawdown around 26.00 m .(BTN-04) to 70.00 m (BTN-06) under ground surface.