There is only limited movement of water between the lakes and sea through a narrow channel at The Entrance, and hence tides in the main body of the lakes are negligible. On occasions, this channel has slowly silted up with sand and the lakes have been completely cut off from the Pacific Ocean until a large flood scours out the channel again. It has been suggested that there was once a second entrance on the Budgewoi Peninsula, and although there is little evidence of this being the case since European settlement, occasionally waves do wash over the dunes into Budgewoi Lake during spring tides.