Identifying Flood-Prone Areas due to Sea Level Rise in nearby communities of Imbang River in Western Visayas, Philippines

Publication Date : 2016-07-22
Author : Saripada, N. B. A.Patiño, C. L.Sinogaya, J. R.
Countries : Philippines
Disaster Management Theme :
Disaster Type : Flood
Document Type : Research Paper
Languange : en
Link :

Abstact :

Coastal communities and habitats are always threatened with the continuing rise of sea levels. The consequences of sea level rise worsened by climate change can bring higher and more frequent flooding to low-lying land areas and loss of near shore coastal habitats. Coastal communities are highly vulnerable especially during typhoon events, inevitably leading to loss of properties and ultimately lives. It is important to identify which communities are highly at risk from flooding and submersion. In this study, nearby communities of Imbang River in Western Visayas, Philippines affected by sea level rise are identified and quantified. These communities are quantified by mapping building structures using an automated building extraction approach on LiDAR data and orthoimages. The extraction methodology applied an object-based image analysis to segment, classify and extract buildings. The total area of the extracted buildings using the automated extraction method is 3.16 km2 covering 2.18% of the 144.76 km2 floodplain.  Meanwhile, affected areas are identified by deriving the flood extent due to sea level rise in nearby communities of Imbang River using a thresholding query based approach on digital elevation model. The flood extent was determined by using different scenarios of sea level rise categorized as low (1-meter rise), medium (5-meter rise) and high (20-meter rise) level. Almost 35% to 80.4% of the total land building areas will be flooded under the three different scenarios. The highest inundated area of building structures affected by sea level rise is estimated to be about 2.54 km2 on the 20-meter sea level rise, while the lowest estimated to be about 1.113975 km2 on the 1-meter sea level rise.