Interactive comment on “ Short communication : Field data imply that the sorting ( D 96 / D 50 ratios ) of gravel bars in coarse-grained streams influences the probability of sediment transport ” by

Our response: We have focused the introduction and better specified the hypothesis to be tested. The thresholds for motion of coarse-grained sediment particles are set by assignments of values to the Shields variable φ. As the reviewer indicates, there is a large body of literature on this topic. However, most analysis concur on the notion that a range of φ-values between 0.03 and 0.06 adequately constrains the threshold conditions for sediment entrainment along streams where energy gradients are between 0.001 and 0.03 (please see compilation by Lamb et al., 2008), which is the case in our setting. We explained this point more carefully in a new section where the Monte Carlo simulation is described. We additionally add a new section where we justify the assignments of uncertainties to the variables.