Use the HAND model for mapping the areas more susceptible to flooding in the Rio Uruguai

Abstract

The aim of this study was to use the HAND model to map areas more susceptible to flooding in an area of the Uruguai River and tributaries, near the Itaqui city, Rio Grande do Sul State, using as a base a flood event occurred on 10/26/1997. An image classification of a Landsat 5, TM sensor, was carried out to generate a reference map with the flooded areas to compare with the HAND model simulations. The flood height was defined based on the data quota of Itaqui Station, located on the Uruguai River, on the day analyzed. Simulations by HAND model and the classified reference map were compared by fuzzy similarity, Kappa index and overall accuracy. The daily quota value of 11.45 m, of Itaqui station in Uruguai River, was critical to adjust and evaluate the flood simulation generated by HAND model. Such cota value was not enough to flood the urban area of the Itaqui city. Flood simulations with 15 m, 19 m and 23 m yielded by the HAND model indicate that the west, north and south areas of Itaqui city are more susceptible to flood. Considering the free availability of data, and the fast and satisfactory availability of results, this methodology can be applied in other regions, and may serve as a tool for planning and management of areas at flood risk.