Simulation of the climate variability effects on sediment production in a river basin using the Erosion Potential Method model integrated with climate models

Abstract Integrated modeling systems are used to identify the effects of climate variability on future sediment production, assisting in watershed management. In this study, an integrated modeling system composed of erosion and climatological models was used to evaluate the effects of climate variability on sediment production in the Itaqueri river basin, state of São Paulo (Brazil). For this, we used climate data generated by the ETA-MIROC5 and ETA-HadGEM2-ES models for future estimation of sediment production using the Erosion Potential Method (EPM) model under RCPs 4.5 and 8.5. The Itaqueri river basin presented an average annual production of sediments equivalent to 9.41 Mg. ha-¹. year-¹, which considering the total area of ​​the basin is equivalent to 208,467 Mg. year-¹. Considering the sediment retention rate, the actual sediment loss in the current scenario (2019) was 22,306 Mg. year-¹. Regarding the effects of the variability of climatic elements, in the medium term (2070) the average annual production of sediments in the basin may increase by up to 61.8% (RCP 4.5) and 30.5% (RCP 8.5). In this same period, the actual loss of sediments could reach 36,076 Mg. year-¹ and contribute to the silting and reduction of the useful life of the Lobo reservoir. The EPM model proved to be effective in identifying areas with the highest production of sediments and, in an integrated manner with climate models, it can help in a preliminary and preventive way in identifying the effects of climate variability. However, uncertainties related to the adoption of climate elements are regularly included as part of the risk in water resources management.