In steady open-channel flows, anisotropic turbulence is observed due to the existence of free surface. Open-channel flow has its own peculiar distribution of turbulence characteristics. Especially in the critical open-channel flow in which the Froude number becomes unity, turbulence intensities do not show the universal distributions. This may be caused by Bradshaw (1967)'s hypothesis that the inactive motions composed of low frequency and flow history become more dominant. In unsteady open-channel flows, effects of inactive motions are expected to be more dominant for the distribution of turbulence intensities. In this study, turbulence measurements in the outer region, especially in depth-varying zone, were conducted accurately by using two-component LDA. The effects of free surface on the turbulent structures are discussed in detail.