ORIGIN OF CHANNELS USING DIGITAL SURFACE MODELS IN THE UPPER WATERSHED OF THE VINCES RIVER (SANTO DOMINGO DE LOS TSÁCHILAS, ECUADOR)

The definition of the hydrographic network of a basin merits the precise location of the beginnings of the channels since this position has an important influence on the dynamics of a hydrographic basin. Geographic Information Systems (GIS) together with Digital Surface Models (DSM) allow the location and extraction of drainage networks in an automated way, however, these results often require verification in the field or in different sources of information to validate and achieve high accuracy. The objective of this research is to determine and evaluate the best threshold for locating the beginnings of channels in the upper basin of the Vinces River (province of Santo Domingo de Los Tsáchila in Ecuador) using a Digital Surface Model (DSM). The evaluation of the accuracy of the automatic models obtained was compared with the results obtained from high-resolution satellite images and field control campaigns. The main results indicate variations in both the length and the number of sections according to threshold that have an impact on the results of the work. It is very important to choose an optimal threshold to obtain the drainage network model closest to the territorial reality and from there to obtain reliable and functional data.