MEASURING FLOOD RISK IN RATNAPURA TOWN AREA IN SRI LANKA
DOI:
https://doi.org/10.17501/iccc.2018.2203Keywords:
Flood, Forecasting, Risk, ARIMAX-GARCHAbstract
Flood is a common chaotic natural problem frequently occurring in Ratnapura district. Recent chain of flood events that occurred in Ratnapura district has raised the question regarding the capability of defending civilian lives and property from this natural disaster. Ratnapura town area mainly face flood risks due to the over flow of Kalu river during the South West monsoon season. Flood risk cannot be directly measured. But flood risk is directly proportional to the river water level. When river water level is increasing, flood risk also increases. Since river water level can be taken as a measurement for flood risk, this analysis is based on forecasting river water level of Kalu River. Data were collected from meteorological stations at Ratnapura, Galabada, Guruluwana and Lellopitiya which are located in upper catchment area of Kalu River. ARIMAX-GARCH model was fitted to forecast water level using the rainfall data and the water discharge rate. The accuracy of the fitted model to forecast water level was high when comparing the estimated values with the actual values. Therefore the ARIMAX-GARCH model can be used to measure the flood risk in Ratnapura town area.
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