Assessment of environmental degradation due to anthropogenic processes based on critical zones: a study in a basin in southern Brazil

Abstract

Different land uses imposed by human activities have affected biotic and abiotic components, modifying the natural environment according to population growth and increasing the environmental impact over time. As a consequence, the relevance of studies to evaluate the magnitude and aspects of environmental changes is increasing. In this context, the Ribeirao do Pinheirinho Basin (Sao Paulo state, southeastern Brazil) was selected for this study, since it is part of a region that recharges a set of drainage channels that provide water to several municipalities (approximately 2 million people), primarily during dry seasons. Additionally, this basin has been intensively used for agricultural purposes over the last 50 years. To determine the current characteristics and to analyze the environmental changes, this study was based on temporal and spatial analyses of the components of the basin’s critical zone at a scale of 1:10,000. In association, due to water availability issues, the HOST (hydrology of soil types) classification was adopted, as well as previous data, satellite images, aerial photos and results of laboratory and field tests. As a result, anthropogenic activities have changed the depth, areal distribution, and environmental functions of geological materials. These activities have affected the relationship between rainfall, infiltration and surface runoff, resulting in a lower groundwater level and decreasing water availability. In conclusion, the adopted methodology aids in the assessment of the changes in the environmental area of study. This could be useful for environmental recovery projects as well as the establishment of environmental policies.