Determination of channels heads from digital surface models. upper basin of La Ventana stream (Buenos Aires, Argentina)

Abstract

When defining the hydrographic network of a basin, it is important to precisely locate the beginnings of the channels, since this position influences different aspects of the dynamics of a basin. Currently, the evolution of Geographic Information Systems (GIS) and the existence of Digital Surface Models (DSM) make it possible to extract drainage networks automatically, however, on many occasions, these results require verification in field or in different sources of information to validate and achieve greater precision. Therefore, the objective of this work is to determine and evaluate the optimum location threshold of the channels heads location of upper basin of La Ventana stream (Buenos Aires, Argentina) through the use of a DSM. To evaluate the suitability of the automatic models obtained, the results were compared with high-resolution satellite images and field control. In turn, morphometric indices were used to determine the variations in the hydrological response of each model. The main results indicate variations both in the length and in the number of sections according to the threshold that affect the results of each index. Is highlighted the importance of choosing an optimal threshold to obtain the drainage network model that is most consistent with reality from which valid and specific data can be extracted.