The problem of reservoir inflow forecasting plays a critical role in reservoir management. However; reservoir inflow forecasting must be necessarily accurate and timely. This paper presents practical machine learning (ML) technique and the optimal... lead time for reservoir inflow forecasting. The two well-knows ML: Support Vector Regression (SVR) and Random Forests (RF); were used to predict water inflow volume into the reservoir. Both methods will improve the efficiency of the reservoir inflow