Spain - Aragon Flood Susceptibility - Spatial Data Infrastructure of Aragon

Data in Spanish

Map Scale 1:50.000

The methodology applied for the zoning of the susceptibility to flooding is based on geomorphological criteria. The cartography of the GEODE at scale 1 / 50,000 has been completed with the geomorphological cartography of the SITAR in the small areas where the first was not available (see section 1.3.1.2.).

The layer of alluvial deposits provided by the Ebro Hydrographic Confederation has been added to the generated coverage, where the materials are classified as alluvial, low terraces, medium terraces and high terraces. This coverage is of good quality but is not complete for all channels, focusing on the main channels.

With this procedure, a complete cartography base of the geology and geomorphology has been obtained from the available information. Given that the generated cartography has diverse sources of information and that the GEODE has also been obtained from the MAGNA maps without the legends being totally unified, a specific work has been done to correlate the different legends and be able to classify the territory according to their susceptibility to flood.

Through this correlation work, the territory has been classified into the following geomorphological formations: Alluvial, valley bottoms, floodplains, dejection cones, channel deposits, meander deposits, first order terraces, second order terraces, glacis and other training.

The level of high susceptibility is associated with geomorphological formations located in the riverbed itself or its vicinity and correspond to sedimentation materials from the fluvial system with relatively recent dating. This implies that they are areas of the territory through which the flow of water is likely in situations of high rainfall.

The average level of susceptibility is associated with geomorphological formations related to water flow, but with a less recent geological dating (terraces of second order), which are usually farther from the channel and whose probability of water flow in avenues is much lower. to areas of high susceptibility. The areas of low susceptibility correspond to places in the territory where the risk of flooding originating in the flow of water circulating through the rivers is less probable, being further away from the channels.

For the verification and verification of the results, the hydraulic detailed studies have been used. These studies provide very good accuracy, but they are only available in very local areas. A layer has been generated from all the flood sheets available for T = 500 years.

This layer has been superimposed on the susceptibility mapping obtained in phase 2.

The sensitive coincidence between the flood sheets and the area classified as HIGH susceptibility has been verified, allowing to validate the proposed methodology.