Combining the Soil and Water Assessment Tool (SWAT) and MODIS imagery to estimate monthly flows in a data-scarce Chilean Andean basin

The focus is on the application of the SWAT model for the Lonquimay River basin (Central Chilean Andes), a small sub-basin of the Biobio, in which snow accumulation and snowmelt dynamics play an important role. In the absence of local measurements of snow coverage, remotely-sensed snow cover information (MODIS) was combined with discharge time series in order to validate the model representation of stream hydrology and spatial snow cover extent. The results showed satisfactory to good general model performance in terms of representation of long-term or annual mean discharge at the basin outlet, as well as a reasonably good description of snow cover extent under most circumstances. The case study also provides an example quantitative indication of how well a model may perform under limited availability of input meteorological data. In the current work, the MODIS snow products were used for validation purposes only. The future inclusion of MODIS information directly into the model calibration process is suggested as a means to further improve the results.