DETERMINATION OF THE HAZARD INDEX FROM THE MAPPING OF SUSCEPTIBLE AREAS TO FLOOD WITH THE HAND MODEL

Código

END113

Autores

Bernardo Pires Caron, Masato Kobiyama, Roberto Fabris Goerl

Tema

9 - Medidas estruturais e não estruturais para prevenção de desastres

Resumo

Every year, several Brazilian cities are affected by floods. One of the most efficient and simplest flood disaster prevention measures is the identification and mapping of areas of flood susceptibility. Thus, the objective of the present work was to map flood hazard areas of the municipality of Igrejinha-RS, based on the results of the Height Above the Nearest Drainage (HAND) model. A DEM of 2.5 m resolution was used. From the reclassification of the HAND topology, three flood susceptibility thresholds were generated: low, medium and high. The result of the HAND topology was used to calculate the flow depths. The flow velocity was obtained using the Manning equation along the slope raster obtained from the DEM. With the velocity and the depth, the hazard index (HI) was calculated for the three susceptibility thresholds. The results evidenced both the usefulness of this new methodology and its limitations. As for the variables, it was observed that the depth affected the HI variation more, due to the low velocity found.