Hydrological Response to Predominant Land Use and Land Cover in the Colombian Andes at the Micro-Watershed Scale

Abstract

The hydrological response (HR), generally defined as the relationship between rainfall and runoff, should be understood holistically within the processes of the conversion of rainfall to evapotranspiration, surface and subsurface runoff, groundwater flow, and streamflow. The objective of this study was to evaluate the HR of three predominant land use and land cover (LULC) types in the Colombian Andes at the micro-watershed scale. Experimental micro-watersheds were established to replicate LU (pasture, and a coffee agroforestry system) and LC (natural forest). The TETIS model was applied, calibrated, and verified, and the similarity between observed flows (using level sensors and volumetric gauges) and flows simulated by the model was evaluated, relating the HR to each type of LULC. The HR included an analysis of the Water Retention and Regulation Index—IRH and Base Flow Index—IFB. The best model fit and HR were found for the agroforestry system, with a moderate NSE (0.48), R2 (0.7), RMSE (0.2), and BE (20.8%). On the other hand, a forest cover was found to guarantee the permanence of subsurface inputs and base flows to the river, as evidenced by high IRH, IFB, and water balance values. Natural forest land uses present high volumetric moisture content in the soil, corresponding to a high IFB.