Effects of Climate Change and Land Use on the Hydrologic Regime Using the Hydro-bid Tool: Andean Mountain Basin Case Study

Abstract Changes on the land surface from human activities or natural events generate changes in land cover, which directly effect water availability and quality in watersheds. This article evaluates the effects on the hydrological regime Andean Mountain basin case study on the Coello river basin in Colombia due to changes in land use/land cover during the 2000–2019 period by the use of the Hydro-Bid tool. The physical analysis of the land surface included the processing of Landsat 7 ETM and Landsat 8 OLI satellite images for the years 2001, 2003, 2015 and 2019. Seven types of coverage were determined based on these data using the Mixed Gaussian Method that is part of the dzetsaka plugin in QGIS. The changes between each year were evaluated, after which the land use/land cover change for the year 2050 was predicted using a Markov chain in the TerrSet software package. The multitemporal analysis showed a decrease in forested areas during the studied period, while low vegetation significantly increased within the watershed. This trend was shown to continue in the future scenario for the year 2050, where the predicted losses in forest cover were estimated at 135 km 2 with an increase in flow on the watershed of 59.6%. Additionally, the climate change scenarios were modeled with the changes in land use. The combined effects (climate change + land use) established a progressive decrease in the modal flow. The results from this study will allow authorities to improve decision-making in land use planning and climate change adaptation. However, uncertainties associated with data availability and modelling performance must be taken into account when applying the presented results.