APPLICATION OF GEOSPATIAL AND HYDROLOGICAL MODELING FOR RUNOFF ESTIMATION IN LEBIR RIVER BASIN, MALAYSIA

Abstract. Non-stop heavy rain had happened on 15th December of 2014, causing flood in Kelantan districts. Approximately 250 of flood victims in three districts were involved and relocated to six temporary relief centres. A hydrological model is designed to simulate the runoff process for a catchment area. In this study, Hydrologic Engineering Center Modelling System (HEC-HMS) and Rainfall-Runoff-Inundation (RRI) modeling method were used in the simulation of flow hydrograph for the Sungai Lebir catchment. Establishing the simulation at Sungai Lebir using the both models may help in analysing large-scale flooding in the future. The use of HEC-HMS and RRI require data of precipitation and flow rates obtained from the Department of Irrigation and Drainage (DID) centre. There are two main processes in the modelling stage namely calibration and validation. A total of two dates of rainfall events used for the calibration process; the events on December 5, 2014 to December 11, 2014 (Calibration 1) and December 15, 2014 to December 20, 2014 (Calibration 2) which resulting low NSE value for Calibration 1 with −9.806 and −0.312 for HEC-HMS and RRI, respectively. Whereas for the validation process, two sets of events on December 1, 2001 to January 7, 2002 (Validation 1) and November 16, 2013 to December 23, 2013 (Validation 2) have been used, resulting that HEC-HMS outperformed RRI with the recorded value of 0.817 and 0.821, for Validation 1 and Validation 2, respectively. The results indicate that the flow rate computed using the HEC-HMS software is not significantly different from the actual flow rate, and it also demonstrates the suitability of the HEC-HMS software for use in flow rate estimation.