A GIS-based framework for urban flood modelling and disaster management

Mr. J.C.W. Ediriweera

Abstract

Floods can be generally considered in two categories, flash floods and general floods. Flash floods occur within a minutes after heavy rainfall. This situation generates an urban flood. Flood disaster is recorded to cause about the third of all natural disasters in the world. For the purpose of flood disaster management planning, computer based flood modelling studies are carried out to understand the physical system of the flood plane, as a general practice. At the same time the concept of flood hazard mapping is becoming a more and more important to the society to better understand floods and on

such basis minimize the interaction with the flood event and to minimize the flood damages. Flood hazard zones are usually generated based on the basis of flood depths and velocities. However, the computer based flood modelling result does not give any integration of velocity and depth to produce flood hazard maps. Therefore, this research study is aimed to develop a GIS based framework to produce hazard zones. At the same time this study approaches to asses and visualise the tangible and intangible flood damages by manipulating thousands of data with different formats such as polygons,

poly line, point, raster, etc, on one GIS based platform. Further to that, this research demonstrates the capabilities of traffic planning and evacuation strategies, with the help of network analysis tool on the same GIS based framework to minimize the flood damages in future.

Keywords: Flash Flood, Computer based flood modelling, GIS, Hazard map, Flood damages, Tangible, Intangible, Disaster, Planning, Decision making