Environmental monitoring and hydrological simulations of a natural wetland based on high-resolution unmanned aerial vehicle data (Paulista Peripheral Depression, Brazil)

Abstract

The main biofuel produced in Brazil is ethanol representing 16% of energy production in the national energy matrix, that is why sugarcane is one of the most important crops for Brazilian agriculture. The land conversion associated with the advancement of agriculture is often carried out inappropriately advancing over areas of high environmental sensitivity, such as natural small wetlands. The level of detail required to monitor subtle changes in their dynamics and landscape makes very high-resolution images (+ 10 cm/pixel resolution) acquired by unmanned aerial vehicles (UAVs) an excellent data. The objective of this research was to use UAV orthomosaics and digital elevation models to carry out seasonal monitoring, simulate the water flow in the areas of hydric-contribution and inland flooding, and validate the flooding simulations. The studied wetland located in the State of São Paulo (Paulista Peripheral Depression), showed a seasonal surface water storage capacity (28,067 m³) and a loss of approximately 12.27% of its total area between October 2019 and February 2020. The flooding simulations were validated with data observed by the imagery (variation of ± 3.27%.), being possible to be reapplied in several small ecosystems.