Water availability and extreme events under climate change scenarios in an experimental watershed of the Brazilian Atlantic Forest

• Published in: The Science of the total environment 2024-10, Vol.946, p.174417, Article 174417
• Main Authors: Costa, David de Andrade, Bayissa, Yared, Villas-Boas, Mariana Dias, Maskey, Shreedhar, Lugon Junior, Jader, Silva Neto, Antônio José da, Srinivasan, Raghavan
• Format: Article
• Language: English
• Subjects: atmospheric precipitation; Brazilian Atlantic Forest; climate; climate change; Climate variability; ecosystems; environment; environmental sustainability; evapotranspiration; Hydrological modeling; model validation; rain forests; Soil and Water Assessment Tool model; stream flow; SWAT model; temperature; United Nations Framework Convention on Climate Change; water stress; watersheds
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.174417

Climate change has diversified negative implications on environmental sustainability and water availability. Assessing the impacts of climate change is crucial to enhance resilience and future preparedness particularly at a watershed scale. Therefore, the goal of this study is to evaluate the impact of climate change on the water balance components and extreme events in Piabanha watershed in the Brazilian Atlantic Forest. In this study, extreme climate change scenarios were developed using a wide array of global climate models acquired from the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Reports (AR6). Two extreme climate change scenarios, DryHot and WetCool, were integrated into the Soil and Water Assessment Tools (SWAT) hydrological model to evaluate their impacts on the hydrological dynamics in the watershed. The baseline SWAT model was first developed and evaluated using different model performance evaluation metrics such as coefficient of determination (R2), Nash-Sutcliffe (NSC), and Kling-Gupta efficiency coefficient (KGE). The model results illustrated an excellent model performance with metric values reaching 0.89 and 0.64 for monthly and daily time steps respectively in the calibration (2008 to 2017) and validation (2018 to 2023) periods. The findings of future climate change impacts assessment underscored an increase in temperature and shifts in precipitation patterns. In terms of streamflow, high-flow events may experience a 47.3 % increase, while low-flows could see an 76.6 % reduction. In the DryHot scenario, annual precipitation declines from 1657 to 1420 mm, with evapotranspiration reaching 54 % of precipitation, marking a 9 % rise compared to the baseline. Such changes could induce water stress in plants and lead to modifications on structural attributes of the ecosystem recognized as the Atlantic rainforest. This study established boundaries concerning the effects of climate change and highlighted the need for proactive adaptation strategies and mitigation measures to minimize the potential adverse impacts in the study watershed. [Display omitted] •High flow events may increase 47.3 % demanding preparedness against flooding events.•Low flow periods may decrease 76.6 % with severe implications for water management.•Climate change results in non-linear effects across water balance components.•Evaluating climate change effects helps governments to prepare effectively.