BELLAMBI LAGOON EMERGENCY MECHANICAL ENTRANCE OPENING FOR FLOOD MITIGATION

Recent large ocean swell increased water levels in the lagoon and the height of the berm at the mouth of Bellambi Lagoon is preventing water to flow back out, creating localised flooding. The proposed work will open Bellambi Lagoon to the ocean, with a 1m-wide channel, long enough only to break through the berm. This will be done near high tide, and if possible with rain if it is forecast. The opening will be sufficient for scouring flow to develop. The backhoe operator will dig a pilot channel from the oceanward end toward the lagoon approximately a bucket-width wide with the bed graded to the ocean. The last section of the channel (at the lagoon end) to be opened at the time of the next possible high tide (i.e. the highest possible tide of the day). Initiation of a breakout at this time is likely to result in the most effective and sustained mechanical breakout due to the increasing head difference through the course of the breakout.