As dimensões do risco hidrometeorológico na cidade de Vigia de Nazaré-Pa, Zona Costeira paraense

Abstract

The city of Vigia de Nazaré, located in the Northeast of Pará, Estuarine Continental Sector of the Coastal Zone of Pará, has a historical problem of flooding, caused mainly by the effects of the tide, the rainy season with considerable accumulations of precipitation and incorporation of the fluvial-marine floodplains to the urban area. The general objective is to understand the relationship between the dynamics of floods and the occupation process in the city of Vigia de Nazaré-PA, producing a diagnosis of risk to extreme hydroclimatic events, considering temporal factors, as well as those of coastal dynamics, which in line with converge to the reality experienced by the local population. Therefore, it will be necessary to understand the process of occupation in the city of Vigia, mainly on the floodplain area, the dynamics of hydrometeorological phenomena and define the dimensions of the risk in Vigia, based on socioenvironmental data. To produce the analysis, the research had data from the Centro de Hidrografia Marinha (CHM) were used, for tidal prediction, from the National Agency for Water and Basic Sanitation (ANA), to understand the seasonality of precipitation, and still, an aerial survey was carried out through a cooperation with the Management and Operational Center of the Amazon Protection System (CENSIPAM-CRBE), aiming at the production of a very high resolution Digital Terrain Model (MDT) to determine the area covered by the floodplain and an orthomosaic to visualize the urban features, among others. The socioeconomic (IBGE, 2010; IFDM, 2010) and health (DATASUS, 2014; 2016) data, in order to recognize the municipality's vulnerability to risk in relation to others in the coastal region, were adapted from another study, incorporating other health data, from a DATASUS source. Statistical and geoprocessing tools were applied to these data to compose the analyses. The main results found were: it is a historical problem, resulting from a socially constructed risk, accepted by the population and neglected by the public power; ⅓ of the occupation of the urban area is on the fluvial-marine plain, under the influence of the tide, with a large part of this area recently incorporated into the urban space, more strongly from the 1980s, in the context of the recent restructuring of the Amazon regional space. Its natural dynamics includes semi-diurnal tides, reaching 4.56 m; has an intense rainy season, for the regional characteristic of the eastern Amazon, with the highest accumulated precipitation in the months from January to May, between 307.1 mm and 489.9 mm, with the rainy quarter, FEB-MAR-ABR, passing 400 mm of rain and 25 days of average daily rainfall frequency (FDPRP). Still, there are records of flooding events affecting more than 4000 residences in the urban area, and these events were frequent during the researched historical series (1991-2020). The municipality still has a high socio-environmental vulnerability to risk, among the municipalities in the coastal region. These and other results can form a diagnosis on the hydrometeorological risk of the city of Vigia, providing subsidies for actions at various scales, whether environmental monitoring, disciplining and guiding land use and occupation, and also in investments in social areas and in the health in order to mitigate the effects of flood events