In this research, the flow energy dissipation efficiency in the dissipation chamber section has been studied by constructing a physical model with a scale of 1:10. In this regard, with the aid of dimensional analysis, the influential factors affecting the performance of the flow energy loss in dissipation chamber were Froude number, ratio of drop total height to shaft diameter, and ratio of sump depth to shaft diameter. Then, 144 experiments were performed by a full factorial experiment design in way that 4,3, and 3 levels were considered for Froude number, ratio of drop total height to shaft diameter, and ratio of sump depth to shaft diameter. Additionally, four replications for all possible combinations of effective factors have been included. The minimum and maximum of flow energy dissipation efficiency values were measured 73.9% and 88.3%, respectively. Moreover, in order to maximize flow energy dissipation efficiency, the optimal values of three contributing factors (i.e., Froude number, the ratio of drop total height to shaft diameter, and ratio of sump depth to shaft diameter) obtained 2.32, 13.901, and 1.467, respectively. A regression based equation in form of a quadratic polynomial was proposed to estimate the value of flow energy dissipation efficiency with the coefficient of determination of 0.7196. Generally, the measured flow energy dissipation efficiency changed from 73.90 to 88.30%