Alterações ambientais na Bacia Hidrográfica do rio Marapanim, Pará

The watershed is considered the territorial unit for the implementation of the National Policy of Water Resources and where the activities of land cover are concentrate. These activities altering the vegetation cover of the watershed, which directly influences the surface temperature, since the vegetation functions as a temperature regulator. In this context, the preservation of vegetation along the watersheds is considered of fundamental importance because it allows the protection of the soil to the occurrence of erosion processes, contributes to the infiltration of water in the soil and the maintenance of the microclimate. Thus, the objective of this study was to evaluate the changes in the vegetation cover of the Marapanim river watershed, comparing values of NDVI (Normalized Difference Vegetation Index) and surface temperature for the years 1995, 2004 and 2016. It was used the Satellite images (Land Sat 5 and 8) and processed to obtain the NDVI and the surface temperature of the years of analysis. The results showed that there was a loss of vegetative in this period, as well as a decrease of 2.06 °C in the average temperature from 1995 to 2004 and an increase of 3.43 ° C from 2004 to 2016. The areas with the lowest values of NDVI presented the highest temperatures, mainly urban areas, showing the influence of vegetation in the microclimate. In this context, this study can support the formulation of public policies to promote the sustainable use of natural resources in the area of the basin.