Vortex formation in the head pond of a hydroelectric power plant has been studied experimentally in a scaled hydraulic model. Velocity vector field and the turbulent kinetic energy distributions were measured using an Acoustic Doppler Velocimetry (ADV). Free surface flow in the head pond was also simulated using Flow-3D software. Comparison of measured and computed flow variables were satisfactorily good, promising the use of CFD tool to identify surface vortex and calculate its strength from the numerical solution. Vortex strength was evaluated numerically and then it was shown that it can be used as a key parameter to investigate the performance of a given head pond design.