Author(s)

ALFREDO RAMÓN MORTE, JOSÉ TOMÁS NAVARRO CARRIÓN, ESTELA GARCÍA BOTELLA

Abstract

The behaviour of floods depends on two main factors: Manning’s roughness coefficient and the threshold runoff, P₀. In both parameters, land cover plays a vital role in the characterisation of small streams, which traditionally are altered in the Mediterranean basin. However, in the absence of an assessment protocol that optimises the geographical information stored in the official repositories, studies in these areas tend to be subjective, depending on the personal criteria of the technicians in charge of the study. In this paper a new method is proposed for the determination of these parameters, based on the integration of the Spanish national system for the mapping of flood-prone areas (SNCZI), which was designed by the Spanish Geological and Mining Institute (IGME), and the spatial data of the Spanish land cover and use information system (SIOSE database), designed by the Spanish National Geographic Institute (IGN). The methodology generates roughness data based on objective criteria and on a threshold runoff map, which can be reviewed by the technician in charge of the study, but which is based on updated, regulated and open official data. The result is a thorough hydrological and hydraulic characterisation, which has been tested in a western Mediterranean area characterised by the complexity of land use: the foothills between Sierra Helada and Sierra de la Cortina in the Municipality of Benidorm, located in the province of Alicante, Spain.

Keywords

flood risk, SIOSE, hazard, runoff, P₀