Changes in atmospheric and hydrological dynamics at the Colombian Amazon in scenarios of forest loss

The Colombian Amazon exhibits complex hydro-meteorological features, as it links the biggest tropical rainforest of the world with the Andes range and the savannahs of the Orinoco basin. Similar to other amazon areas in neighboring countries, this high-biodiversity region faces severe deforestation due the agricultural expansion, illegal logging, and mining. Numerous studies have stated the role of the Amazon over the climatic system, and the complex interactions between the rainforest, the atmospheric dynamics and the hydrological response of the rivers. Furthermore, previous studies have warned about the effects of the loss of vegetal coverage in the Amazon over hydro-meteorological patterns in northern South America.

This work aims to study the effects of deforestation over some atmospheric and hydrological features in the Colombian Amazon. Taking into account present and historical rates of deforestation, there are defined scenarios of moderate and intense forest loss. Changes in precipitation and moisture fluxes over the area are investigated using the atmospheric model WRF (Weather Research and Forecasting). High-resolution simulations are performed for a study period composed of typical rainy and dry months, considering the changes in land use of each scenario. The effects of forest loss over streamflow in some rivers of the region are assessed using the results from the atmospheric model and simulations in an aggregated hydrological model. The main finding suggests that low-level moisture flux over the Colombian Amazon and neighboring Andean foothills decrease with the reduction of the rainforest cover in both of the considered seasons. As a consequence, precipitation decreases over the area, triggering a reduction of the streamflow in the studied rivers.