GIS-Based Assessment of Groundwater Vulnerability to Contamination in Boracay Island Using DRASTIC Model
The study was conducted to assess the vulnerability of groundwater resource to contamination in Boracay Island, Aklan, Philippines, using the DRASTIC model in combination with Quantum Geographic Information System (QGIS). Specifically, the study determined the vulnerability of groundwater resource to pollution contamination by computing its vulnerability index. From this, a groundwater vulnerability map was developed and policy intervention recommendations were formulated targeted to ensure the sustainability of ecotourism industry on the island. Results confirmed the high vulnerability of Boracay Island’s groundwater resources to contamination and that unregulated pressures due to tourism development could lead to the further degradation of its groundwater and coastal resources. In terms of spatial extent, the groundwater resources of Boracay Island that were found to be vulnerable to contamination are as follows: approximately 410.28 ha (40.87 %) are moderately vulnerable; 562.37 ha (56.01 %) are highly vulnerable; and 30.95 ha (3.08 %) are considered as very highly vulnerable. The study likewise exhibited the combined use of the DRASTIC model and Quantum GIS as an effective method for groundwater contamination vulnerability assessment. It also demonstrated the effectiveness of the model in developing vulnerability maps and the combined use of the model and QGIS in identifying vulnerable areas to contamination that can aid in policy making, planning and management interventions to attain sustainable ecotourism industry in an island ecosystem. The immediate legislation of local ordinance to construct sewerage system on identified critical areas is recommended to mitigate the deterioration of aquatic resources in Boracay Island in the future.