Rainfall threshold analysis for flooding events in Bauru City
Marina Alves Ferraz Pedrini1; Julio César Rodrigues Gonçalves2; Ilza Machado Kaiser1; Anna Silvia Palcheco Peixoto1; Geórgia Jorge Pellegrina1
1 Univ Estadual Paulista; 2 Bauru Municipal Administration
Baixar PDF doi:10.20906/CPS/CB-10-0005
Resumo
Due to climate change observed in recent decades and the subsequent increase in the frequency and intensity of extreme natural events of hydro-meteorological and climatological origin, a greater emphasis on natural disasters studies in both literature and institutional reports have been noticed. According to the IBGE (2013), 37.1% of Brazilian municipalities have been hit by flooding in recent years and Bauru City is inserted in this statistical. Pellegrina (2011) proposed a methodological approach to geoenvironmental problems analysis based on natural disasters database, now available at IPMet website. Such tool allows the risk determination areas, contributing to the warning systems efficiency, as well as to the logistics of the victim assistance agencies, urban planning and proposal of public policies. The analysis of this database indicates that the rains are the trigger events with a higher incidence of damage, here classified as moderate rainfall; cold front with continuous rain; and heavy rains. The damage linked to urban drainage are rated into flooding, highlighting the floods are not always easily differentiated between gradual floods, flash floods and river overflow. Cross-analysis of damage and their triggering events related to rain indicates that heavy rain is the most significant event for the occurrence of natural disasters related to drainage. This research extends the analysis related to flooding occurrence with daily rainfall data, accumulated rainfall and consecutive days with rainfall, to assess the triggering rainfall threshold event of disasters in Bauru-SP. For this purpose, the physical environment data were evaluated by mapping the locations and frequency of events obtained from the Bauru Municipality, confronting the IPMet database information. Rainfall data were obtained from weather stations installed in the city. The occurrence probability of the events was estimated using the IDF (intensity, duration, frequency) equation parameterized for Bauru city. However, it should be no
Palavras-chave: natural disaster database; flood area mapping; IDF equations; severe rainfall