Flood Hazard Maping Using QGIS Spatial Analysis in Bangko and Masjid Watershed at Riau, Indonesia

Abstract

Flooding is a natural occurrence hazardous to people and properties and produces environmental and economic losses, especially in flood-prone areas. This study will be used to assess flood risk in the Bangko and Masjid watersheds. To analyze it, flood hazard mapping is arranged by slope, land cover, elevation, rainfall, buffer zone, and soil type, which is done with the help of a Geographic Information System (GIS), specifically QuantumGIS (QGIS). This system tool assesses each variable utilizing satellite spatial data and categorizes the vulnerability being very high, high, medium, low, and very low. Each map arrangement value is combined using an overlay value to determine the flood susceptibility. According to the mapping results, the Bangko and Masjid watersheds are highly vulnerable to flooding. Based on the results of the mapping, in the Bangko watershed 61% of the total area is vulnerable to flooding, and 20% has high to very high vulnerability, while in the Mosque watershed 84% of the area is vulnerable to flooding and 11% of the total area has high vulnerability. to very high. After validation of areas that are often affected by floods, it is known that these areas are in vulnerable to very vulnerable areas. This is due to the low watershed elevation and flat slope and high rainfall, as well as residential areas close to the river in the watershed. This is due to the watershed's low elevation and flat slope and the high rainfall, and the residential area close to the river in the watershed area. Hence, it is vital to establish a convenient and straight-off understandable flood hazard map that emphasizes the management mitigation effects.