The crestline approach for assessing the development of coastal flooding due to sea level rise

One of the most pressing issues in studying the impacts of sea level rise (SLR) triggered by climate change is understanding the development of the hazard of permanent coastal flooding. The issue persists because available approaches are based on the mapping of the inundated area where they explore the coastal flooding development across terrain elevations, that is—horizontally. In addition, they overlook the existing structures along or in the vicinity of the coastline, which have inherent hydraulic properties that may affect the development of such flooding. The purpose of this study is to develop a novel approach for assessing the development of permanent coastal flooding due to SLR at cross sections along the coastline, that is—vertically, in full consideration of underlying hydraulic properties of the existing coastline. An approach was developed using analogy of existing coastline to a contiguous weir. This approach was named crestline approach and was developed as a four step GIS-based approach that could be applied at any coastal zone. An example application on one of the top ranked cities in the world prone to the SLR threat has been provided to illustrate exactly how to apply the crestline approach. The novelty of this approach lies in its ability to accurately identify the specific locations where coastal flooding will initiate, in full consideration of existing natural/manmade coastal structures. This study is significant for the opportunities it provides to analysts and decision makers to better understand the development of permanent coastal flooding.