Atenuação dos impactos do adensamento urbano na dinâmica hidrográfica da sub-bacia do córrego Botafogo, Goiânia, GO

Abstract

In order to understand the process of urbanization, in view of the dynamic character transformations introduced in the natural environment, which alter the hydrographic system in urbanized basins, with direct impacts on drainage, technical assessments are required with a systematized approach of the basin as a unit of analysis and planning . The objective was to evaluate the evolution in the form of land cover and use and its direct implications in the hydrographic dynamics in the Botafogo stream sub-basin, located in the central region of the capital Goiânia (GO), as well as to propose and test the efficiency of guidelines that may result in scenarios in order to mitigate the impacts resulting from these changes, considering the years 1988, 1998, 2008 and 2018. The methodology establishes the relation of the evolution of land use and occupation in the last four decades in the sub-basin of the stream Botafogo and corresponds to changes in hydrographic dynamics in the studied area through the application of the rational method and hydrological modeling, presenting changes in the processes and spatio-temporal hydrological phenomena, such as surface runoff coefficient, infiltration, effective precipitation and flow estimates. The data were processed by specific GIS software for spatial scaling, scaling and thematic mapping. Based on the application of the established model, in order to meet the objectives proposed in this study, the main flow lines and their contribution potential were identified in order to confront proposed guidelines to mitigate the effects of urban Botafogo stream basin. As the research is about the representation of spatiotemporal phenomena, with information and results of quantitative and qualitative character, they are presented in forms of maps and graphs, as well as the confrontation of these with the literature and analysis of its importance in relation to the urban and environmental planning. The results show that the transformations related to the use and occupation occurred in this sub-basin led, over time, to several environmental consequences, such as: high soil waterproofing index, suppression of vegetation cover, channelization and potential reduction natural drainage of the stream, infrastructure of the drainage system poorly dimensioned. In addition, changes in hydrological dynamics (concentration time, effective precipitation, infiltration, runoff, flow estimates) due to the evolution of urban land cover and use have been related, which associated with the physical characteristics, resulted in the convergence of flow to the main channel and making it susceptible to flooding and flooding.