Efeitos da urbanização sobre vazões de pico de enchente

Abstract

The frequency and magnitude of floods occurrence in some Brazilian cities led the development of this study. The main goal of in increasing knowledge about the interference of the shares of land use issues related to urban flooding and investigation of adverse effects from the correlation between the human occupation and urban drainage system. Through Bibliographical Review has been made between diagnostic instruments for management use and occupation of land and issues related with floods, such as the Urban Managing Plans, with the aid of geoprocessing tools, such as Geographic Information Systems and study of techniques that considered the influence of the use and occupation of the ground for definition of outflows of projects of draining systems. To quantify the increases in flood flows resulting the advances of urbanization, characterized by an increase in impervious areas, there was a case study in the basin of the stream of Monos, Cachoeiro of Itapemirm, ES, where it can compare current conditions and future regard to considering the flow of flood by methods Rational, Modified Rational, the Soil Conservation Service and Snyder in four different scenarios: pre-planning and initial developments, present and future. From the results provided by multitemporal analysis of soil surface cover, performed by quantification of permeable and impermeable areas of land, we can conclude that the advancement of the process of urbanization in the watershed of the stream of Monos have significant effect on the system water in the region. It can be observed also as tools for use and occupation of the soil can significantly increase the peak flood in output. Thus, the results generated by the application of models for simulation of peak flows indicate that the influence of the urban density on the growth of these flows is significant. The techniques of GIS, were used as good alternatives for minimizing the difficulties of spatial elements of water and soil use and occupation. The integration of GIS software of the type with the processes of assessment of water resources has, effectively, to represent the spatial and temporal variability of the elements involved.