The natural landscape of Boa Vista city is composed of a dense drainage network wich has been replaced by the urban sprawl that spreads upon watercourses, streams, swamps and lakes. This natural landscape has been the scene of population and city growth, more intensely since the 1980s. The main objective of this study is the spatial and temporal analysis of the landscape change from 1985 to 2014, using the geotechnologies of Boa Vista city (Roraima, Brazil), seeking for an understanding of the changes in this locality. To fulfil the aim were performed fieldwork, collection of points in GPS, photos, descriptions of the landscape and bibliographic review. The use of geotechnology was relevant in the analysis and treatment of Landsat 5 satellite images of the years 1985 and 1995, CBERS 2 of 2005 and Landsat 8 of 2013 and 2014, in wich atmospheric correction and image processing was made for supervised classification of soil use through MAXVER procedure (maximum verisimilitude). The drainage extraction and elaboration of sub-basins was made from the TOPODATA. The image use provides visualization and interpretation of changes in the lakes landscape as a result of urban sprawl. For the seven lakes were developed maps of APPs (permanent preservation areas) as a case study. The geographical science with the geotechnology assistance can support the decision-making process, pointing that the results of interpretative analysis of images are reliable, showing that the basins were changed with the density of the lakes, of which are springs. Therefore, are sensitive and important areas for local and regional water dynamics but yet their natural limits have been replaced by urban sprawl over the years. It is observed that the environmental authorities have been trying to avoid urban sprawling and illegal occupation to preserve the area around lakes. The analysis shows the need to monitor and implement joint actions by the government to inhibit the occupation of APPs and planning for the city’s growth in compliance with the legislation to avoid the disappearance of lakes and springs that are so important for the dynamics of the water bodies of Boa Vista. The importance of this research is the construction of new knowledge and information that may support the environmental and urban planning to ensure the preservation of the existing lakes.
|
