Identification of runoff processes in a small undisturbed catchment in the Chilean Andes - Experimental study and modelling

Hydrology of the Tres Arroyos in Malalcahuello, Chile

Preliminary results

Preliminary results suggest the importance of fast processes for rainfall runoff response on the one hand as well as of considerable dampening effects of a large storage on the other hand. There is evidence of preferential flowpaths resulting from the textural differences between different layers of volcanic ash (from gravel fraction to silty sand). However, connectivity of these gravel layers along the hillslope is necessary in order to make them hydrologically relevant on catchment or even hill slope scale. In the near-stream zone, flow reversal between groundwater and surface water has been observed under certain conditions. With the help of physically based models it is possible to test these perceptions gained from point data for their importance on hill slope and catchment scale.