Landslide and flood risk assessment in a rapidly urbanizing municipality of Costa Rica

Abstract

Landslides and floods are among the most prevalent hazards in tropical and developing regions, often exacerbated by rapid urbanization and unregulated land management. Santa Ana, a rapidly expanding municipality in Costa Rica, presents a unique mix of high-value residential properties, commercial hubs, agricultural lands, and protected areas, making it vulnerable to both landslides and floods. This study integrates geomorphological (morphometric and morphogenetic) methods to assess landslide and flood hazards, considering key variables such as slope, L-S factor, terrain roughness, topographic wetness index, and flow accumulation. Additionally, socioeconomic data—including population density, infrastructure, and land use—are combined with the Social Development Index (SDI) to evaluate exposure and vulnerability. Through the use of normalized indices, a comprehensive risk map is developed, highlighting high-risk zones, particularly in districts like Salitral and Brasil, where steep slopes and dense hydrological networks coincide with higher socio-economic vulnerabilities. The study provides an adaptable framework for disaster risk management, applicable to regions with limited data availability, facilitating timely and informed territorial planning decisions aimed at mitigating risks and enhancing community resilience.