Land use appropriation and pressure in watersheds: a mapping proposal to support environmental studies

Abstract

Land use, without proper management, can lead to a set of degenerative impacts on the physical environment. The spatialization of different forms of land use and their consequent deleterious influence on the natural landscape is substantial for environmental studies. In this context, the present work aims to evaluate the intensity of the appropriation process of sugarcane monoculture on watersheds and river channels, through a proposal adapted to environmental analysis. The procedures were based on geoprocessing techniques operated in a Geographic Information System (ArcGIS 10.8), adopting the sub-watersheds of the Aguapeí River-São Paulo, as the territorial unit. Regarding the land use class, sugarcane was considered, taking into account its area in the years 2003 and 2023. As a result, the Sugarcane Appropriation Index of Sub-Watersheds (SAISW) and the Sugarcane Pressure Index on Drainage Channels (SPIDC) were obtained. Both indices showed a decrease in the Very Low class and a substantial improvement in the others, with emphasis on the Medium class. In the case of the SAISW, the decrease in the Very Low class was from 79% to 31.5% between 2003 and 2023. On the other hand, the Medium class, which represented 1.4% of the territory in 2003, rose to 32% in 2023. Similarly, the Very Low class of the SPIDC corresponded to 74% (2003) and 31% (2023) of the area in question, while its Medium class increased from 2.4% to 25% over the same period. The methodological proposal presented can be adapted to other forms of land use; furthermore, the indices can be correlated with other environmental variables, supporting environmental planning and studies aimed at mitigating impacts associated with human activity.