Investigation of landslides and floods utilizing a geographic information system (A case study: Trenggalek Regency, East Java)

Trenggalek Regency is an area that is affected by floods and landslides every year. This study aimed to map areas that are prone to floods and landslides in each district using Geographic Information System (GIS) and Remote Sensing. In its processing, this disaster hazard map used secondary data sourced from the Shapefile Ina-Geoportal, soil type map, DEM data, BMKG data, Google Earth imagery, and BPS data for Trenggalek Regency which are then processed using ArcGis 10.7 software. These produced parameters for making flood and landslide hazard maps in the form of rainfall, slope, soil type, land use, and exposed population in Trenggalek Regency. After classifying, scoring, and overlaying the existing parameters, flood and landslide hazard maps were generated. The flood hazard map covered seven districts of the Trenggalek Regency, including Tugu, Karangan, Trenggalek, Pogalan, Gandusari, and a small part of Kampak are very prone to floods with an average of the districts in Trenggalek Regency have a result of fairly prone to floods. Meanwhile, the landslide hazard map shows that several districts such as Trenggalek, Watulimo, and Panggul have a high landslide hazard level, while the dominance of other areas is landslides with a moderate hazard level. With this processing, it can be seen that areas with high populations and residential areas are prone to floods or landslides.