Priority areas for natural regeneration and reduction of sediments in the Atibainha Basin

Abstract

Erosion is a physical process generated by the action of rainwater causing disaggregation, transport and deposition of soil particles. This process is natural and occurs in all terrestrial surface. However, erosion has been intensified by inadequate anthropogenic action. The presence of vegetation cover on the soil reduces the possibility of erosion, slope collapse and siltation of water bodies, that is, it contributes to the protection and preservation of soil and other environmental systems. Since the summers of 2013-2014 and 2014-2015, there have been news reports regarding the low level in the reservoirs of the Cantareira System. The combination of inadequate soil use, low rainfall rates due to a drought period and temperatures above the normal conditions, high demand of water and lack of collective conscience of Brazilian consumers for the rational use of water are factors that have caused a water crisis. The global overexploitation of ecosystems is causing impacts on ecosystem services provision, bringing out the importance of adequately conceptualize, quantify, map and monitor water ecosystem services. Satellite images can be used to evaluate and monitor the delivery of water ecosystem services. The evaluation of water supply and water damage mitigation services can greatly benefit from the use of satellite products, contributing to a better understanding of the processes and functions that underlie its provision to guide decision makers. InVEST and RIOS, used in the present study, are tools for spatial and temporal analysis of the provision of ecosystem services in the ecological-economic context. The present work aims to define priority areas with high potential for natural regeneration that promote reduction of sediment exports at the lowest cost in the Atibainha Basin, in the Cantareira System, São Paulo. The output from the scenarios indicate that, for the Atibainha basin, areas with regeneration potential above 70% can also contribute to the reduction of sediment supply. Thus, it is considered that, by indicating the areas with regeneration potential above 90%, it is possible to obtain the provision of this hydrological ecosystem service at the lowest investment cost and greater probability of success in the restoration. The provision of hydrological ecosystem services for sediment reduction and the regeneration potential of the Atibainha basin are spatially related. Thus, it is concluded that it is possible to apply the natural regeneration, at the lowest cost, to the restoration of priority areas that promote the improvement of water quality in the basin.