Risco hidrometeorológicos em área urbana do município de São Luís - MA: vulnerabilidade, perigo e suscetibilidade associados

Abstract

The knowledge of the relationship between climate and human activities has been a constant focus of the study of geographic science. This relationship is highlighted, mainly, in the analysis of the socioeconomic impacts caused by extreme episodes of precipitation, especially the hydrometeorological risks to which society is increasingly exposed. Taking into consideration the Brazilian scenarios of extreme rainfall episodes (floods and inundations), it is proposed to identify the municipality of São Luís-MA, through a study that allows emphasizing these extreme rainfall episodes, their risks, and socio-environmental consequences. It focused on the urban environment. As a theoretical approach, it was necessary to understand the risk in its hybrid dimension, addressing the following aspects: vulnerability, danger, and susceptibility of populations in risk areas. From this context, the present dissertation aimed to analyze the hydrometeorological risks associated with pluvial extremes. To this end, the analyses developed are based on the assumptions of Geographic Climatology, based on the Urban Climate System (UCS) and Urban Environmental System (UES), which, in an integrated analysis, served as support for the understanding of the variability of pluvial extremes. The Rainfall events were characterized as extreme using the Quantil technique; the Mann-Kendall test was used to identify the trends; some analyses were performed based on the historical series of rainfall in the period 1991 to 2020; the susceptibility of the study areas was assessed by means of multicriteria analysis between declivity, hypsometry, land and soil use; and vulnerability assessed by means of field activities in risk areas identified by Civil Defense, in which variables related to the physical-environmental and socioeconomic dimensions were surveyed. The data were also collected in digital media about the impacts of extreme storm episodes on the city and its populations. The results made, it possible to highlight the following aspects: I) the extreme years of rain are associated with the occurrence of La Niña, and the series of rains under study showed a non-significant decreasing trend; II) in relation to hybrid risks: risk overlap, susceptibility, vulnerability and danger to risk areas, especially the populations of Vila Marinho, Vila Socó and Veranil/Matança; III) In the survey of qualitative data collected in the field, some patterns of physical vulnerability were evidenced-environmental and socioeconomic impacts in areas at risk in São Luís; IV) regarding extreme episodes: the impacts in the municipality of São Luís were more evident in the last five years with rainfall above 20 mm in 24h according to the digital media survey; V) The susceptibility mapping found that 70% of the studied areas were identified with high susceptibility, especially by housing occupation close to rivers and streams. However, these analyses aimed to contribute as subsidies to the management of climate risks in the urban environment.