ANALYSIS OF FLASH FLOOD POTENTIAL INDEX (FFPI) AND SCENARIOS ASSESSMENT IN SHAH ALAM USING GIS APPROACH

Abstract

Nowadays, there is an increase in the frequency of flash floods, which can have disastrous effects on both the economy and people's lives. In this study, the flash floods in Shah Alam are analysed using the Flash Flood Potential Index (FFPI) assessment method, which utilises four significant parameters, namely ground slope, land use, soil type, and NDVI, as outlined in the FFPI model that was first developed in 2003. The study reveals that the study area has a medium risk of flash floods, with an index value of five (5) to six (6). Flash flood risk is considered in all study scenarios, with a probability of over 50%. Scenario 2 produces the best results, with a 71% chance of Shah Alam being hit by a highlevel flash flood and a 22% chance of being hit by a medium-level flash flood. Since the FFPI is a dimensionless index ranging from 1 to 10, and the percentage of FFPI in Shah Alam is 47.48% for the value of 5 (median index), it is concluded that Shah Alam is in the medium risk group for daily flash floods. The FFPI is a suitable index to be used in Malaysia for predicting urban flood risk. Additionally, it is recommended to incorporate the calculation of factors or parameters that contribute to flash floods using weighting and ranking, particularly related to the drainage system and precipitation.