Streamflow modeling in the Colombian Andes: insights from watersheds with diverse physical properties and climate patterns

The Andean region of Colombia, characterized by high climate variability and watershed complex topography, gives rise to the main rivers of the Colombia fluvial network, essential for agriculture, ecosystems, consumption, and hydropower generation. This study evaluates the spatially lumped Sacramento Soil Moisture Accounting (SAC-SMA) model for 12 Colombian watersheds located in the Andean region with different climate regimes and geomorphological features. SAC-SMA Model performance was evaluated with Nash-Sutcliffe, Kling–Gupta efficiency, and Percent Bias. The model shows good performance, exhibiting NSE values > 0.5, KGE > 0.5, and Bias −9.8% for the calibration period and NSE > 0.3, KGE > 0.4, and Bias −7.5% for the validation period. The model results demonstrate the ability of the SAC-SMA model to accurately represent mid-range flows, moist conditions, and dry conditions in nearly all the studied watersheds. However, the model encounters difficulties in capturing high flows.