Application of HEC-RAS Model for Flood Inundation Mapping in Sungai Golok, Rantau Panjang

Abstract

Flooding is a constant concern to achieve the Sustainable Development Goals (SDGs) in Malaysia, particularly in the state of Kelantan. This study focused on the issue of floods triggered by Sungai Golok from a hydraulics viewpoint. The goal of this study was to develop a flood mapping along Sungai Golok in Rantau Panjang town that specifically aimed at reducing floods and impacts on SDGs. The dry and wet areas on the flood mapping were simulated using Average Recurrence Interval (ARI) for a staggered period of 10 years, 50 years, and 100 years. An unsteady flow analysis was performed with the aid of the Hydrological Engineering Centre -River Analysis System (HEC-RAS). In addition to that, this study deployed the QGIS tool to develop and re-project an appropriate topographical profile of the Rantau Panjang region. It was determined that the value of 0.035 for the Manning's was acceptable because all data for the initial calibration satisfies the condition of relative percentage difference RPD ≤ 25%. The HEC-RAS concluding outcome was calibrated and validated using statistical testing. The extent of the floods on 19 February 2016, and after 10 years later was found to be generally comparable in magnitude. After a period of 50 years, an increase in the discharge to 119 m 3 /s caused the flood's magnitude to expand at a faster rate. With a peak flow of 140 m 3 /s after a period of 100 years, it proved that the whole area will be inundated in floods. Highlighting these SDGs' aim at achieving healthier lives and well-being of the inhabitants, the flood mapping is essential in the flood risk area to forecast the varying patterns of floods, which in turn used to ascertain the level of flooding in Rantau Panjang and subsequently reduce the impacts.