A Spatial Sensitivity Analysis of Flood Control Capability in the Mandalika Special Economic Zone, Central Lombok Regency, using a GIS-Based Multi-Attribute Decision Making Approach

Abstract

The Mandalika Special Economic Zone (SEZ) on Lombok Island continues to develop as a national strategic area, particularly driven by rapid tourism expansion. Intensive land-cover changes, vegetation degradation, and increasing rainfall in recent years have contributed to the rise of recurrent flooding. These conditions highlight the need for a deeper assessment of flood sensitivity to support mitigation efforts and adaptive spatial planning. This study aims to evaluate the MADM scoring–weighting process, identify dominant parameters and the effects of weight variation on flood sensitivity, estimate the extent of vulnerability classes, and formulate mitigation recommendations for the area. Six parameters were used: rainfall, slope, elevation, land cover, river density, and population density. The Multi-Attribute Decision Making (MADM) method was applied using two weighting scenarios (35%–13% and 25%–15%), supported by visual verification based on morphology, color distribution, and administrative boundaries. The results indicate that medium-vulnerability zones dominate the study area, especially in transitional regions between lowlands and hilly terrain. Land cover and slope emerge as the most influential parameters, producing more stable and logical spatial patterns with weights of 0.30 and 0.25. Elevation and river density fall into the moderate-influence category, with weights of 0.15 and 0.12. Rainfall and population density show lower discrimination due to data limitations, with respective weights of 0.15 and 0.08. Land cover and slope also demonstrate the highest sensitivity, while elevation, rainfall, and river density show moderate sensitivity, and population density represents the lowest level. Medium vulnerability dominates the study area at 50.66%, followed by low vulnerability at 26.52% and high vulnerability at 22.83%. To reduce flood risk, government authorities and area managers should strengthen land-cover rehabilitation, improve spatial-planning regulations, reorganize river networks to enhance flood-control capacity, and manage population density through zoning and development monitoring.