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Understanding the Impacts of Climate Change on the Water Cycle in the Itacaiúnas River Basin

22 March 2023

Effective integrated water management (SDG6.5) is underpinned by catchment-level data and approaches.

The Itacaiúnas River Basin, Brazil, is an important watershed for the mining sector in the Carajás mineral province of Brazil where Vale operates. In line with the ICMM principles of catchment-based water management for the mining industry, researchers at Vale Institute of Technology (ITV) have studied the Itacaiúnas River Basin to understand its water resources and how deforestation and climate change might impact the water cycle in the Basin in the future.

Since the 1970s, there has been large scale deforestation in the Basin and now more than half of its native forest has been lost, mainly replaced by pasture. Using hydrological modelling, remote sensing techniques, and in situ data, ITV observed that further deforestation could result in a further decrease of water transfer to the atmosphere in the Basin and an increase in streamflow. The increased flow in the local water system is associated with water quality issues and flooding. While decrease in water transfer when combined with climate change is expected to extend dry periods in the region.

The conservation of the forest that still remains, therefore, is essential for the health of freshwater ecosystems. Through a partnership with Chico Mendes Biodiversity Conservation Institute, Vale helps to protect and monitor Conservation Units in Carajás region (800 thousand hectares of forest), including in the western Itacaiúnas watershed. The results showed that deforestation that occurred upstream of the Conservation Units affects the rivers in the Conservation units and may change water quality and biodiversity even in pristine areas.

The results of the study show the importance of the local forests in providing water vapour to the atmosphere and therefore, to climate regulation. They also highlight the value of protecting and restoring water-related ecosystems (SDG6.6) to reduce the impacts of climate change in the region and prevent water quality deterioration. Together, these results are underpinning improved water management in the basin and allowing researchers to identify and evaluate how water-related risks can impact watersheds, which Vale will be able to replicate in different locations across its portfolio.