There are found numerous methods to measure flow in open channels. The simulation of water flow in channel requires mathematic calibration of the structures in channel so that the water level and the discharge become compatible with demand. Sluice gate is one of the most important structure which can perform in free and submerged flow. In this research, there were experiments on a sluice gate mounted in lab flume of 12.5 m, 0.6 and 0.65 length, width and height, respectively, in the slope of 0.0002. Some equations of measuring the discharge from the sluice gate extracted from Energy equations and Momentum were calibrated using two metaheuristic algorithms of simulated annealing and ant colony. After the sensitivity analysis of algorithm was done, the optimal coefficients of discharge obtained for the Conventional equation of discharge in free and submerged flow was obtained 0.686, and 0.881. Also, in calibration of Energy-Momentum method for submerged flow, the optimal contraction coefficient was 0.533. finally, the methods were assessed and compared for which the statistical indexes show the favorability of results
