Environmental flow releases (EFR) to the Snowy River were made in November 2010 and October 2011. For each release, the effects on the inlet entrance morphology and tidal response were measured on four field trips to cover the flow peak and recovery. Water level recorders were deployed in the principal channels over the period of the release and, for the 2011 release, for the prior two months and year following at Marlo. Each EFR raised water levels in the estuary but the changes were attenuated by the large storage capacity and the relatively open entrance of the estuary. Entrance scour was minor and occurred primarily in the intertidal zone, showing that the entrance was close to equilibrium for the EFR. This result was confirmed by analyses of the sediment transport capacity and through use of an attractor plot of the entrance dynamics. A measure of entrance changes before and after the 2011 surveys was provided by the use of a moving-window analysis of the tidal record and confirmed the value of this method. Instantaneous values of entrance scour and deposition were predominantly tidally driven but river flow biased the net scour/deposition, leading to scour on the rising and peak stages of the EFR and rapid deposition late in the falling stages. The role of tidal asymmetry was shown to be significant. The attractor map, which showed the evolution of the depth as the river flow varied, provided a useful tool for interpretation and prediction of probable changes.