Flood studies, flood areas, river flood riskbyJavier Caballero Ingeniería y Proyectos
Civil engineering studio or cabinet. The engineering service offered includes prior advice to the client, execution and drafting of floodability studies (or floodable areas), and monitoring of the entire management process and approval of such studies by the corresponding Hydrographic Confederation.
The aim of these studies is to analyse the response of rivers/watercourses to different floods, both in current and future situations, thinking about the execution of possible works.
In this sense, the European Directive 2007/60/EC on Flood Risk Assessment and Management introduced new criteria to be taken into account in the protection of the public hydraulic domain and in flood risk management for the protection of people and goods.
The application of these criteria has made it necessary to modify various aspects of the Public Hydraulic Domain Regulation (last updated in December 2016), leading to the implementation of the National Floodplain Mapping System (SNCZI) and the publication of various Guides, including the Technical Guide to support the application of the RDPH in the limitations of land use in floodplains of fluvial origin.
Engineering studies of floodable areas, floodability or flood risk are carried out, in general, at the request of the corresponding Hydrographic Confederation in order to authorise a specific action, in the following phases:
- Phase 1: If available, review of previously performed studies and report of alternatives, which in turn include: review and analysis of the hydrological and maximum flow studies of the basin (specific well obtained through the CAUMAX Maximum Flow Map) and hydraulic studies of the rivers and channels carried out for the National Flood Zone Mapping System (SNCZI); revision of the National Catalogue of Historical Floods; and preparation of the report of conclusions, establishing proposals and recommendations to the client both from the point of view of the hydrological study and the hydraulic study of floodable areas.
- Phase 2: Realization, if necessary, of new hydraulic models, generally two-dimensional (2D), which in turn include: acquisition of the cartographic model necessary for hydraulic modeling (model LIDAR 2x2 m2 or 5x5 m2 of the National Geographic Institute); visits to the study area, during which the drainage elements of the different infrastructures existing in the area (motorway, railway, etc.) are checked; that can influence the floodable area under study; elaboration of a hydraulic model of the current situation in the cabinet using the appropriate software (HEC-RAS, IBER, etc.); establishment of previous conclusions; creation of a hydraulic model in a modified situation (using the appropriate software, HEC-RAS, IBER, etc.); and elaboration of the report of results and conclusions; and, where appropriate, proposals for flood protection in the study area.