Multitemporal Monitoring of Surface Water Dynamics in Lake Tota (Colombia) Using Landsat Imagery and NDWI: A Replicable Methodological Framework

Remote sensing has become an essential tool for understanding environmental dynamics, particularly the long-term monitoring of surface water bodies. Among spectral indices, the Normalised Difference Water Index (NDWI) has shown strong potential for detecting and quantifying changes in water surfaces using multispectral satellite imagery. This chapter presents a replicable methodological framework for the multitemporal analysis of surface water dynamics based on Landsat imagery and the NDWI index, integrating conceptual explanation with a step-by-step workflow accessible to researchers, professionals, and students. The proposed methodology is applied to Lake Tota, the largest natural freshwater lake in Colombia, using Landsat images from 1985 to 2025. The results indicate a net reduction of 125.24 hectares in surface water area, equivalent to a decrease of 2.29% relative to the baseline year, together with marked interannual variability and a declining trend in recent years. Beyond the case study, the framework offers a transferable approach for monitoring surface water changes in different geographic contexts, contributing to more informed decision-making in environmental management and research.