MODELLING OF GROUP DECISION SUPPORT SYSTEMS FOR FLOOD ALERT WITH NAKAYASU SYNTHETIC UNIT HYDROGRAPH IN GADANG WATERSHED

Abstract

Natural disasters still occur regularly and continuously in Indonesia and in the world, such as floods, earthquakes, tsunamis, and landslides. The impact of natural disasters such as floods can be reduced through flood hazard mitigation activities. Flood hazard mitigation can be done by knowing early rainfall in history and today and river water levels river flow to a region upstream of the history and current. This study aims to make a group decision support system modeling for early detection of candidate flooding caused by the condition of the watershed, in this case is Gadang Watershed. The system is designed as a tool to detect candidate field hydrometric flood early. Modelling Group Decision Support System (GDSS) was developed based on the analysis of flood design represented in a Nakayasu Synthetic Unit Hydrograph. A group of Decision Support Systems is a type of computer-based interactive system that is designed for a group of decision-making. The users of the decision support system are a group that consists of some people. Hydrograph is in accordance with the conditions of the watershed, especially in tropical Indonesia. The results of the design flood serve as a reference to the operational unit, the data management unit, and the planning unit of the institution of the watershed maintenance such as Perum Jasa Tirta I. A suitability test is intended to determine whether the distribution of the selected distributions may be used or not, in a series of data available. Analysis of the suitability test using the Chi Square distribution. From the results of the distribution test that the distribution can be accepted and the system can support for analysing flood hazards as preliminary information early detection of flooding. Keywords: Group Decision Support System, Flood Hazard, Nakayasu Synthetic Unit Hydrograph, Water Level DOI： https://doi.org/10.35741/issn.0258-2724.58.1.13