Diagnóstico ambiental e o processo de urbanização na microbacia costeira do Rio da Prata, na região metropolitana de São Luís, Maranhão

Abstract

This work presents the environmental diagnosis of the coastal watershed of the Rio de la Plata, highlighting its uses and land occupation in the surroundings of the basin. The justification was given by the need for studies and planning in areas of coastal basins that follow the trend of coastal occupation and are the target of real estate speculation due to the acceleration of the urbanization process that advances in fragile areas. The study aimed to analyze the geoenvironmental conditions and types of use at the heart of the activities carried out in the soil of the microbasin. The theoretical basis was based on the legislative framework, at the state, federal and municipal levels, in what concerns the environment and natural resources, making a comparison between environmental laws and urban practices in the study area. The study area has a direct connection with the sea, thus, the concepts and legislation related to the coastal zone were highlighted in this work. The coastal watershed of Rio da Prata has an area of 6.5 km2, belongs to the so-called Ilha do Maranhão and is inserted in the area of the Maranhense Gulf, which is an estuarine complex containing bays, estuaries and several islands, cut by numerous indentations, being the largest of them, the Golfão itself. The methodology used was structured in the systemic approach, in its conceptual stage, applied to environmental studies as an initial basis, which allowed the integrated analysis of the study area. The practical stage consisted in the execution of the technical-operational procedures that included the use of the technique of photointerpretation and supervised classification through satellite images in a geographic information environment, through the geoprocessing software Qgis version 3.10. The information obtained through the digital images were compared and ratified with the in loco observation work, where photographic records of the highlighted classes in the basin area were collected. As a result, cartographic products were generated to support the discussion and alert to face the environmental weaknesses of the study area. Historically, the process of occupation of the study area follows the trend of urban growth that follows the course of estuaries and coastal areas. It was evidenced the existence of different uses of the basin's soil that demand urgency from the public power in the application of environmental policies to contain the environmental impacts in the Rio da Prata microbasin.