THE INFLUENCE OF LAND USE CHANGE ON LANDSLIDE SUSCEPTIBILITY LEVEL, CASE STUDY: WESTERN PART OF SUMEDANG

• Main Author: Eras Putra, Iqbal
• Format: Theses
• Language: Indonesia
• Subjects: Masalah dan pelayanan sosial lainnya
• Online Access: https://digilib.itb.ac.id/gdl/view/87539
• Institution: Institut Teknologi Bandung

The Regional Spatial Plan in Indonesia can be reviewed based on the disastrous impact on nature caused by natural disasters such as landslides. Post-disaster land use can be different especially when the settlements need to relocate. However, land use changes are presumed to increase landslide incidents. Land use has been studied as a static parameter for landslide susceptibility study while land use as a dynamic parameter is rarely been used. Landslide susceptibility shifted when the parameter had changed. Then, land use changes are closely related to the susceptibility level, as will be identified in this study. The objective is to understand the influence of land use changes on the landslide susceptibility level in the western part of the Sumedang Regency, as recommendations for landslide disaster management based-spatial planning. This landslide-prone area has had intensive land conversion since the existence of Cisumdawu Toll Road, several universities, and the industrial zone. Land use classifications are implemented from Landsat 8 Oli imagery to analyze the change of each class from 2013, 2018, and 2024 chronologically. This study employs the Maximum Likelihood Classification (MLC) method to create land use classes by user based on their reflectance features. The land use changes analysis results are used for the input parameter of landslide susceptibility models generated by Frequency Ratio (FR) calculation, with other parameters i.e. geology, slopes, hydrology, and road network. Recommendations are arranged based on landslide susceptibility prediction in 2033 gaining from land use projection by Random Forest (RF) method. The western part of Sumedang features a hilly landscape that forms the upper reaches of the Citarum Watershed (DAS Citarum) and the Cimanuk-Cisanggarung Watershed (DAS Cimanuk-Cisanggarung). This area has a significant history of landslide occurrences, accounting for about 40% of all landslides in Sumedang Regency. Despite this, the portion of the area is slated for urban settlement development. The land use classification results based on Landsat 8 imagery from 2013 to 2024 divided the study area into five classes: forest, bare land, agriculture, residence, and other built-up. Land conversion occurred predominantly in the forest and the bare land, while others tended to expand especially residences in Jatinangor, Cimanggung, and around the toll gates. These changes influence landslide susceptibility, with the Prediction Rate (PR) index of the FR valuesiv reaching 4,725. The susceptibility levels based on FR values generated into four zones: very low, low, moderate, and high. A comparison of landslide susceptibility levels between 2013 and 2024 shows that bare land has the greatest impact on landslide susceptibility, while forest conversion tends to increase susceptibility to landslides. The residence compared to cropland is better for sustained susceptibility, yet other built-up area has little impact. However, landslide frequency was higher in areas where land use did not change. Land use projection in 2033 showed that five areas require attention regarding their susceptibility, i.e. the educational area of Jatinangor, the Gunungmanik – Parakan Muncang area, the Cisumdawu twin tunnel area, Rancakalong Geotheater area, and the urban area of Sumedang. Expansion of residences in Jatinangor and GunungmanikParakan Muncang could increase susceptibility levels, similar to deforestation around the twin Tunnel and Rancakalong area. Land use projections in urban areas are conformable with land use planning, however, riparian zones need to be considered. This study reveals that the Spatial and Regional Plans in the five observed areas align with the levels of landslide susceptibility. However, projections based on existing conditions indicate that field implementation tends to overlook disaster management aspects. Interventions are necessary in these five areas, as they are at risk of changes in landslide susceptibility levels.