Embracing historical information into flood frequency analysis in Florianópolis, Southern Brazil

Código

I-EBHE0166

Autores

Geórgia Cristina da Costa Kumlehn, Gabriel Anzolin, Edson Luiz da Silva, Pedro Luiz Borges Chaffe

Tema

WG 1.01: REHYDRATE - REtrieve historical HYDRologic dATa & Estimates

Resumo

Flood frequency analysis is key for water resources planning and risk management, which involves fitting a probability distribution to flood records. However, the lack of long streamflow records poses challenges in flood estimation, especially for large return periods. One way to improve FFA is by incorporating historical flood information into the time series, such as quantitative and qualitative information from former newspapers and letters. In this work, we collect historical information of floods through 39 pages of the newspaper called ?O Despertador?, which was published between 1866 and 1885 in Desterro, now called Florianópolis, and 400 letters that engineers exchanged between 1830 and 1889. The research focused mainly on information that made clear that, for any river, water overflowed the river channel, for example ?the bridge was destroyed after unusual rain?, ?the crops on the floodplain were ruined?, ?the floodwater invaded our hospital? or ?at the site, the flood was 50 centimeters above the river level?. There are records of at least 20 historical floods during that period and they are distributed mainly on the coastline of Santa Catarina, also a record for Paraguay River and some in the interior of the state. Our findings show that the use of historical information can be a promising approach to improving FFA, increasing its reliability and supporting a better engineering design in scarce data locations.