The Iber two-dimensional model is a useful tool to simulate the hydrodynamic behavior of rivers and their interaction with the topography of the terrain through the use of Digital Elevation Models (DEMs), which allow for greater accuracy of the topography of the terrain. _x000D_
Through the use of this methodology, the comparison of two sections of approximately 2 kilometers for each one of the Congost River is made, which is located in the municipality of Granollers (61,000 inhabitants) and about 30 km north of Barcelona. The upstream study section is fully within the urban area of the town and is in the state of channeling the river that was carried out during the 70s and 80s of the 20th century. The second section, however, is located downstream of the urban nucleus and in a peri-urban area, and in which intervention has been made to partially eliminate the channeling and the transversal structures that fixed the channel have been removed._x000D_
In this modeling, detailed information is available for each section, flow, water speed, bottom profile, speed, surface roughness and topography and has been obtained through the use of LiDAR flights from the Geological and Cartographic Institute of Catalunya._x000D_
Through the use of the Iber model, the behavior of the river channel, speeds, elevation of the water surface, maximum heights will be determined to determine the flood zones for both sections, allowing a comparison of these results and an analysis of the flood flow for each of them the sections. The expected results are that the river reaches greater flood zones in the stretch without channeling, and this information can be very useful for managers and planners of the Congost river bed.

Luz Vega y Joaquim Farguell
Departamento de Geografía, Universidad de Barcelona
895