Author(s): N. D. P. Ransara; K. L. A. Rangana; G. H. A. C. Silva
Linked Author(s):
Keywords: Flood Modeling; Disasters; Flood risk assessment
Abstract: Disaster is, by definition an event which results in great harm, damage or death in human aspects. Not only in human damages but also in economic losses happened subsequently. Natural disasters happen as a result of natural process of the earth while technical disasters cause due to failure in technology. Most frequent natural disasters can be grouped as Hydrological, Meteorological and Climatological disasters. Floods, Storms and Droughts are the most common terms under above groups. These events happen all over the world not only to a particular region. Thailand flood in 2011, Tsunami disaster in Indian Ocean in 2004 and“Katrina”storm in USA brought in to notice of real danger of natural disasters. Flood modeling and mapping have become most essential component in the sense of flood risk management. Historical data in recent decades show that upward trend (The World Bank, GFDRR, 2013) in occurrence of natural disasters over the world. Sri Lanka is an island in the Indian which is having 103 distinct river basins those enriching agriculture and livelihood. However, water related disasters are quite frequent due to the rainfall pattern. Most of the basins are subjected to devastations frequently as cruel weather conditions. Gin River basin is one of them. The river basin boasts many geographic features such as mountains and flat terrains. Entire basin is located in the wet zone, as a result number of downpours receive throughout the year. Central part of the basin is flooded regularly while a massive flood hit the area in 2003, raising water level by 5 meters while 800 houses (Kulathunga, 2013) going under water. Therefore, need of a flood risk assessment and setting up an early warning system for this basin became important and highlighted by many researchers recently. The study consist setting up a comprehensive hydro dynamic model including rainfall runoff modeling and flood mapping. Delft-Sobek is chosen as the modeling tool and Arc GIS were used for mapping. Furthermore, cross sections extracted from a bathymetric survey and Digital Elevation Model (DEM) of 20 meters resolution were used as major inputs of the 2D model.
Year: 2015