THE COMBINATION FLOOD LAKE CHARACTERISTICS AND SIH3 (HYDROLOGY, HYDROMETEOROLOGY, HYDROGEOLOGY INFORMATION SYSTEM) TO BUILD AN EARLY WARNING MODEL FRAMEWORK

The plains of the Mahakam Cascading Lakes (MCL) are prone to annual flooding during the rainy season. One of the first steps in disaster risk reduction planning is to analyse the flood characteristics (FCs) of lakes and building of a model framework for an early warning system (EWS). As such, this study examined efforts to build a framework for a flood EWS by combining the FCs of the MCL with the Hydrology, Hydrometeorology, and Hydrogeology Information System (SIH3). A spatial descriptive approach was employed to analyse the FCs of the lakes using topographical data of the lake and the area surrounding the central Mahakam watershed as well as data on the lake drainage system. The EWS was analysed using the SIH3 based on an automatic water level recorder (AWLR) and automatic weather system (AWS). This system was also combined with the FCs of lakes and community experiences with lake floods. According to a topographical analysis, a bottleneck exists in the southeastern part of the central Mahakam area, which is causing the waters of the Mahakam, Belayan, Kedang Kepala, and Kedang Rantau rivers to be retained in the central Mahakam basin area, thereby causing flooding in the lake. In addition, the hydrographic model and community knowledge indicate that there is a backflow of water due to the presence of a bottleneck. The integration of the change in the water level system from the AWLR and precipitation fluctuations from the AWS at all the gauges in the upper central Mahakam, lower central Mahakam, and Mahakam tributaries can form a framework for an EWS connected to the Disaster Management Agency (BPBD). The EWS can help the community prepare for disaster mitigation and reduce the risk of lake flood disasters.