This study develops and evaluates machine learning (ML) models for forecasting suspended sediment load (SSL) in the Gumara River, Ethiopia, using long-term meteorological and hydrological time series data. Neural network architectures including ANN-MLP, WANN, LSTM, GRU, CNN, and a hybrid ConvLSTM were trained and validated, with feature importance assessed through SHAP and hyperparameters optimized via grid search. The hybrid ConvLSTM achieved the highest predictive accuracy (R2=0.96 training; R2=0.956 testing), outperforming other models. Extreme Value Analysis (EVA) was applied to high- and low-flow events, with hysteresis loops and index values revealing both clockwise and counter-clockwise sediment–discharge dynamics. Overall, the integration of ML and EVA provided a comprehensive framework for capturing complex sediment behavior under varying hydrological conditions. Hybrid deep learning models provide a robust framework for enhancing sediment forecasting accuracy, thereby supporting sustainable river basin management, and enhance long-term reservoir resilience.