Clustering of historical floods observed on Iguaçu River, in União da Vitória, Paraná

Patrícia Cristina Steffen,Júlio Gomes

doi:10.1590/2318-0331.231820170107

Abstract

ABSTRACT The occurrence of flood events has become more frequent, and, in Brazil, there are regions that suffer with the repetition of those events. In União da Vitória, located in Paraná State, Brazil, those phenomena are commonly recorded, generating series of consequences for each flood event, such as financial losses, environmental damages, home losses and deaths. So, since it is not possible to avoid the occurrence of floods, it is necessary to reduce its impacts, and in a scenario of repeated flood events, as observed in União da Vitória, it is justified the clustering of historical floods, aiming to improve the knowledge about the river basin hydrological behavior and to assist in the determination of hydrological models parameters. Clustering analysis aims to establish sets of events with similar characteristics, and, for this, based on fuzzy logic, the present study uses the fuzzy c-means method to cluster Iguaçu river floods, observed in União da Vitória, using a set of different flood severity indicators. The classification defined four clusters, according to different flood severity levels, so-called: low; medium; high; and, disaster or catastrophe. Therefore, by the analysis of similar features among different clusters of events, it is further possible to study the flood formation mechanisms, contributing to the reduction of its impacts, through real-time flood alert and forecasting systems, for instance.

Highlights

Natural disasters such as floods, droughts, landslides and extreme temperatures have hit Brazil and affected thousands of people (EM-DAT, 2015)
Based on the presented considerations, this study aims performing a clustering analysis of historical floods, observed on Iguaçu River, in União da Vitória, Paraná state, Brazil, by means of defining flood indicators and using fuzzy c- means algorithm
The results interpretation has begun with the calculation of the seven flood indicators for each event of the data set, followed by the identification of the most severe events, according to each one of the indicators

Summary

Introduction

Natural disasters such as floods, droughts, landslides and extreme temperatures have hit Brazil and affected thousands of people (EM-DAT, 2015). That concept represents the definition of flood applied to the present work, which is summarized as ‘flow that exceeds the drainage capacity of a river main channel’ (CASTILHO et al, 2005; TUCCI, 2012). In those cases, floods may generate consequences for the region beyond the financial losses, such as the occurrence of deaths and environmental damages, which are called intangible damages, due to the difficulty of translating those consequences into financial losses (MACHADO et al, 2005; MESSNER et al, 2006)

Objectives

Results

Conclusion