Quantitative analysis of land use role on the functioning of montane watersheds: a mass balance approach in micro basins of the Jaguari river (Ribeirão das Posses, Extrema - MG)

Abstract

Water security is one of the most important priorities of mankind, especially for megacities such as São Paulo. Generally, at this city and in the rest of the country the strategies to assure enough water for people follow classic models based on development of infrastructure for collection and storage. Under this scenario of relatively high costs and questionable long-term sustainability, holistic alternatives in which watershed ecosystems services are considered have been receiving growing interest, such as in Projects with Payment for Ecosystems Services, as the one in Extrema, MG, at the headwaters of São Paulo city water supply Cantareira System. However, little is known in quantitative terms about the role of land cover in the functioning of these watersheds. Theoretically, forest restauration in farm areas could result in increased retention within the basin of sediments and nutrients with potential to cause eutrophication in reservoirs, such as N and P. At the same time, water yield might increase or decrease, as a result of increased evapotranspiration or changes in hydrological flow paths. Hence, it is essential that we quantify these processes, in order to discuss quantitatively the best management alternatives that will assure water security. With this project we intend to produce this data from mass balances obtained at paired micro basins (farm x restored forest) in the headwaters of the Jaguari river, in Extrema, MG. (AU)