Role of Inceptisols in the Hydrology of Mountainous Catchments in Southeastern Brazil

Abstract

Mantiqueira Range is the most important headwater region in southeastern Brazil, being responsible for streamflows that feed a significant part of Brazilian hydroelectric energy production. This region is extremely fragile with endemic species like those that compose the upper mountain cloud forest (UMCF), and the dominant soils are typical Inceptisols. These forest environments are rapidly disappearing in Brazil. The changing land use combined with shallow Inceptisols lead to important effects on hydrology. Therefore, studies addressing streamflow behavior in these landscapes are urgently needed for understanding the groundwater recharge process. The objectives of this study were to investigate the role of shallow Inceptisols linked to the land use changes in the streamflow behavior of the Mantiqueira Range region and to understand the mechanisms of water flow into the saturated zone. To validate the study, a comparative analysis was developed for a representative watershed of Mantiqueira Range, whose land use is divided into pasture and Atlantic Forest, known as Lavrinha Creek Watershed (LCW) and a typical UMCF located inside of LCW. The results showed that in general, UMCF has greater potential for water percolation beginning from the surface layer towards the saturated zone. Micromorphological soil images provided useful information about the soil pore system associated with the physical properties of Inceptisols, and this background helped to understand the water recharge process and streamflow behavior. In addition, the water balance for two years (2009–2011) in the UMCF showed that the flow stored in the saturated zone occurs rapidly, increasing its potential for storage, characterized by the process of refilling water in the Inceptisols soil profile under forests in this region.