INTEGRATED HYDROGEOLOGICAL AND GEOPHYSICAL STUDY OF GROUNDWATER RESOURCES IN NORTHERN BANDAR LAMPUNG, INDONESIA

Abstract

Threats to the sustainability of groundwater resources due to increased extraction in the last 30 years are caused by the increase in population density in the Northern part of Bandar Lampung City. Therefore, it is necessary to study groundwater resources to prevent groundwater crises. This study uses hydrogeological and geophysical data to map aquifer conditions. Fifty gravity data and 16 Vertical Electrical Soundings (VES) points were used to model subsurface conditions. Meanwhile, one drilled cutting data is used to tie the cross-section of the 2D model. The results of gravity modelling show the potential for local groundwater aquifers fills fractures and faults above the bedrock. Meanwhile, the results of the VES modelling interpret the unconfined aquifer as being in the sand layer at a depth of 10–25 m and confined aquifer at a depth of 110 m. Between the two aquifers, there is a low permeability zone of interbedding clay and sand thickness of 65 m from a depth of 25–90 m. These results indicate that the condition of groundwater resources in unconfined aquifers is prone to depletion. Furthermore, infiltration ponds could be a solution to maintain the sustainability of groundwater resource storage in Northern Bandar Lampung.