Dinâmica do uso e cobertura da terra em bacias hidrográficas de Frederico Westphalen, RS

Abstract

The monitoring of permanent preservation areas (APP) and watersheds is fundamental for the management of the territory on a local, regional and national scale. Thus, the objective of this study was to evaluate the potential of using high spatial resolution data from orbital images of the constellation of PlanetScope and Rapideye satellites in mapping the impact of land use and land cover in a small watershed located in the municipality of Frederico Westphalen, used in water supply and understand its dynamics. Three Rapideye images from 2009, 2015 and 2020 and a PlanetScope from 2023 (surface reflectance), data from unmanned aerial vehicles (UAVs) and field data were used. Land use and land cover was mapped using the Support Vector Machine (SVM) classifier and with the aid of field inspections. The classes agriculture, pasture, exposed soil and forests were defined. The drainages were delimited manually and the scenario of APPs of 10 and 30 meters were evaluated in the context of the five sub-basins that make up the study area. The analysis showed a strong expansion of the urban area and the presence of exposed soil parallel to a gradual increase in forest cover in both APP scenarios, despite the reduction in the basins as a whole. In general, the maintenance of large forest masses in the study area during the 15 years of analysis was observed. Furthermore, it was evident that the actions of institutions and owners to qualify and recover APPs is a process that takes several years to show results. High spatial resolution orbital images associated to data acquired by UAVs proved to be adequate for monitoring the study area.