Investigating Climate and Land use Change Scenarios in the Magdalena – Cauca Macrobasin, Colombia

Soil-Vegetation-Atmosphere interactions can be modelled by Land Surface Scheme models, which are capable to simulate coupled water and energy budgets, but the implementation of those models is challenging, especially in tropical basins. To better understand the challenges on Land Surface Scheme modelling in a tropical context, MESH, a Hydrology - Land Surface Scheme model was implemented in the Magdalena Cauca macrobasin in Colombia. The model was calibrated and validated, and then it was used to assess the effects of climate and land use change across the macrobasin. Results showed that the model does not perform well on high lands, but performs acceptably on the low lands despite the fact that reservoirs, swamps, and lakes are unrepresented. The model´s results for climate and land use change scenarios featured opposite effects: while climate change tends to provoke less evapotranspiration at the north, and more evapotranspiration at the south, land use changes tend to impact locally, without a single geographic trend. Impacts on discharge are mixed too, depending on the climate change severity scenario, and local land use changes considered. These results are input for best-informed water resources planning and management in the basin.