digilib@itb.ac.id +62 812 2508 8800

The study area is located in the western zone of the Mandalika Special Economic Zone, which is mostly within the Pujut district and Central Lombok regency. The Indonesian government has prioritized the tourism sector as an important sector of economic growth, as a result, Mandalika named as Special Economic Zone (SEZ). Mandalika is predicted to have a rapid growth in population, and demand of fresh water, therefore, this study was carried out to find and project the condition of underground water in next 10 years. Geoelectrical survey for this area was performed by using dipole- dipole electrode configuration. The results of the cross sections shows that, aquifer is located at the top and the aquitard layer is located at the bottom part, with the aquifer layer mostly alluvium layer rock formation which is ticker at the western and eastern sides, but getting thinner in the middle part. The amount of water infiltrating to the study area was calculated to be maximum 391 mm/year in rainy seasons and minimum of 9 mm/year in dry seasons. On the other hand, the water demand projection was calculated to be 1861.24 m^3/day. The result of equipotential head suggest that the water flows mostly from northern part to the southern part of the study area , and the zone budget results indicates that the study area is mostly recharging from the rainfall. The highest amount of drawdown is happening in the observation well SG-50 and SG- 51 with the maximum value of 5.5m of drawdown, and the lowest drawdown is happening in the well SG-20 in the modeling area. The fluctuation in the drawdown graph line indicates that the drawdown is directly related to the dry and wet seasons of the year. Therefor this study recommend to the wells be dig in the western parts especially close to the river area to avoid big drawdown in the area