Hydrogeomorphological analysis for hydraulic public domain definition: case study in Carrión River (Palencia, Spain)

Abstract

Fluvial spaces have a marked reduction at a global level because of anthropic processes, which have generated an increase in elements exposed to flooding. These spaces include natural flow courses and flood-prone lands. In Spain, natural channels are defined as Hydraulic Public Domain assets, whose delimitation is essential for their protection and flood risk management. However, demarcation of these areas with independent hydrological-hydraulic approaches has generated underestimates in the extension of water-covered lands, thus in recent years it has become clear that there is a need to integrate other variables, such as geology and fluvial geomorphology, which allow comprehension of river dynamics from processes that occurred in the past. Therefore, this study aims to contribute to a better understanding in the definition of areas belonging to natural channels through the development of a detailed hydrogeomorphological-historical method applied to Carrion river (Palencia, Spain). For this purpose, Digital Terrain Models were generated from high spatial resolution LIDAR data, on which erosive and sedimentary forms generated by water circulation were delimited, whose process was also supported in ephemeral and topographic evidences collected in field. With this input, depending on dynamic characteristics and river land vegetation, limits of the Hydraulic Public Domain were drawn. The products obtained are made up as optimized elements both for management of natural courses and for delimitation and zoning of new flooding areas by incorporating hydrogeomorphological criteria.