Risk of flooding influenced by environmental factors in urban areas of Macapá and Santana/AP

Abstract

The drainage system of urban watersheds has been neglected as a dimension of basic sanitation in the Amazon. Despite its remarkable sanitary relevance, it is often correlated with the potentiation of flooding, which can aggravate several sanitary, environmental and public health indicators, especially in the Amazon estuary region, when extreme precipitation weather events occur in line with maximum tidal elevations. The objective of the research is to quantify the preliminary risk of flooding of urbanized sectors of the two main cities of the State of Amapá, Macapá and Santana. Specifically, outline current and future scenarios to generate subsidies for the planning of urban drainage systems and stormwater management. The methodological procedures were as follows: a) data collection at the State and Municipal Civil Defense Coordination of Macapá and Santana (CEDEC); b) data processing, literature review, preliminary definition of risk and preparation of thematic maps using the QGIS Geographic Information System; c) field visit for on-site measurement, identification of secondary impacts in rainy season and validation of geographic data provided by CEDEC. The main results were: mapping of the preliminary risk zones in 28 sectors of Macapá, with the following classification: 4 (14.29%) low, 7 (25.0%) medium and 17 (60.71%) high risk of flooding. In Santana, 6 sectors were mapped: 2 (33.33%) and 4 (66.67%) high risk of flooding. It is concluded that the preliminary risk of flooding in rainy season, associated with subnormal clusters around "hangover areas", is enhanced by the elevations of sygy tides of the Amazon River, presenting similarities in both cities in the face of stormwater management problems. The preliminary risk maps presented can be extremely useful for public policies and urban planning, as it favors contingency analysis and spatial planning.