The relations between frequency and duration of large-scale turbulent flow structures in gravel-bed rivers and the distributions of the time intervals between turbulent events are investigated using flow visualisation and velocity measurements. The time of occurrence and the duration and amplitude of large bursting motions were estimated independently from a five minute underwater video and from high-resolution velocity time series sampled at 20 Hz during 38 minutes at three heights above the bed. Results from both experiments show that the frequency-duration relations of the large-scale turbulent flow structures follow a power function with exponents ranging between -1.4 and -1.95, values that are typical of bursting systems (e.g., solar flares). The frequency distributions of time intervals between two successive ejections display an exponential tail. These findings provide models for simulating sequences of large-scale turbulent events in a gravel-bed river, an important step in linking flow turbulence and sediment transport.