Análise dos fatores contribuintes para enchente urbana no município de Coronel Vivida – PR

Abstract

The research has the objective to study the upper Barro Preto river and Várzea stream watersheds, located at the Coronel Vivida City, southwest of the state of Paraná, to analyze the factors that may be contribuing to the occurrence of the urban floods in this city. The methodology consists in studying the morphometry of watersheds by analyzing the rainfall data for the past six years, as well as the use and occupation of the soil in 1980, 2000 and 2012, and realize a field research to visualize the environmental conditions of the studied watershed. For the obtained results on the morphometry of the watershed, the same presented a elongate shape, with an average slope of 2,82% and order 3. According to the rainfall data, the annual average rainfall is 2.116,17 mm/year, with October being the wettest month and August the month with the lowest rainfall. As the use and occupation of land, the urban area, between 1980 and 2012 had a continuous increase of 62%. This increase consequently resulted in an increase of the areas of the streets, causing the soil sealing, but without great influence, as the urban area represents only 7,87% of the total area of the watershed. However, the vegetation area showed oscillations and a decrease of 31% of their area. The agriculture area and the low vegetation also showed oscillations during the period of analysis and finally had a increase of approximately 4,69% in this period. With the increase of the urban area waterproofing the soil, obtained loss of vegetation areas that are contribuing to rainwater superficial flow occurrence. The fact that the region has clayey soil kind, the infiltration rate is lower, generating a greater volume of superficial water flow, being necessary a larger section to rainwater leakage. Without the meeting of the projects plumbers, the Software Canal was used to check the existed section flow designs and found those doesn't have sufficient measures for the disposal flow. Increasingly observed the invasion of the population in riverbeds, along with notdesingned plumbers, forcing the occurrence of overflows and urban flooding in this city. Possible solution could be taken to eliminate the risks of urban flooding or mitigation of them, such the reuse of the rainwater by the dwellers of the city, encouraging people to preserve infiltration areas and construction of percolation basins before the rivers reaching the urban perimeter.