APPLICATION OF MODFLOW FOR GROUNDWATER OVEREXPLOITATION BETWEEN WINONGO AND CODE RIVERS

This research will review groundwater protection due to water abstraction between Winongo and Code Rivers using remote sensing, secondary data and primary data measurements. MODFLOW and ILWIS will be used to determine three dimensional modeling of unconfined aquifer in this area for some scenarios. The objectives of this research are to define groundwater flow modeling, groundwater abstraction modeling and to determine some model scenarios to protect groundwater from overexploitation. Primary data measurement, secondary data measurement and remote sensing interpretation will be used for modeling, calibration, validation and designing scenario of groundwater model in this area. Based on the result, Average rainfall is 1768,803 mm/year, evapotranspiration is 1376,88 mm/year, runoff is 243,97 mm/year, then the groundwater recharge is 147,95 mm/year. Then, aquifer properties in study area show better support for groundwater potency. Next, groundwater flow direction tends to flow to South based on groundwater flow using MODFLOW and three point method. Also, significant drop of groundwater level occurs in the study area due to recent condition of abstraction rate. Therefore, groundwater protection from overexploitation must be applied in the study area is by extracting 2500 m 3 /year, 8000 m 3 /year and 500 m 3 /year continuously in Sleman Regency, Kota Yogyakarta and Bantul Regency in three concentration area in the study area