Climate change is expected to accelerate flood risks in the coming decades as sea levels rise due to global warming (Balcia et al, 2012). This study investigated the risk to future sea-level rise and coastal erosion in coastal communities using a Geographical Information System (GIS)-based risk assessment method. A spatial-based decision- making framework was also proposed for climate change and coastal flood risk management for Cateel, Davao Oriental.
The 21st century soil erosion was predicted using Digital Shoreline Analysis System (DSAS) toolbar in ArcGIS. Three sea-level rise scenarios were considered (0.3 m, 1.0 m, 2.0 m) based on the projected impacts of climate change. Following the UNDRR HEV formulations of risk, the two coastal hazards were integrated with vulnerability and exposure to produce a standardized and quantile-based risk maps using ArcGIS for the study area. Following are the main results of this study:
Under 0.3 m sea-level rise (scenario 1), Barangays Mainit, Sta. Felomina and San Antonio rank the highest risk to future coastal flooding. For the 1.0 m sea-level rise (scenario 2), Barangays San Miguel, Rafael, and Sta. Filomena rank the highest risk to future coastal flooding. Lastly, for the 2.0 m sea-level rise (scenario 3), Barangays San Miguel, Sta. Filomena, and Mainit rank the highest risk to future coastal flooding.
With the higher sea-level rise scenarios (1.0 m and 2.0 m), more inland barangays will be affected by coastal inundation. Inland barangays with higher population density will have higher exposure rates and thus have higher risk.
Policy interventions are recommended to reduce the risk from coastal erosion and flooding. Both soft and hard measures, cooperation of stakeholders and policy intervention play a big role in managing such risk and attending the socio-economic needs of the vulnerable population.