GEOSPATIAL ANALYSIS OF HYDROLOGIC RESPONSE UNITS OF FLOOD INUNDATION AT DIFFERENT SUB-BASINS PARAMETERS IN TERENGGANU WATERSHED, MALAYSIA

Flood is one of the natural events in our environment. It destroys and displaces naturally existing structures found within the Hydrologic Response Units (HRUs). These include the Land Cover/Land use, Soil structure and the topography or the terrain. The method applied was the used of ArcSWAT to determine those flooded sub-basins by simply delineating the whole watershed into different sub-basin parameters. The result proves that what determines the flood influence was the area of the sub-basin that contained the HRUs not the HRUs itself. Once the sub-basin was inundated, the flooded streams within the sub-basins were calculated as flood impact, in this analysis 5 number of sub-basins were flooded in the watershed of Terengganu. Sub-basin number 3 has the highest flood impact with 14,699 hectares and sub-basin number 5 has the lowest total flood impact of 968.82 hectare.