Why do ICOLLs open and close to the ocean?
ICOLLs are separated from the ocean by a sand beach barrier or berm. This entrance barrier forms and breaks down depending on the movement and redistribution of sand and sediments by waves, tides, flood flows and winds. ICOLLs open and close to the ocean naturally in a constant but irregular cycle. When there is sufficient water flowing into the lake or lagoon from the catchment area (usually following heavy rainfall), water levels in the ICOLL will rise. The water levels in ICOLLs can often rise rapidly (within hours or days depending on the catchment size) in response to higher rain events (e.g. 50mm+). Eventually the water in the ICOLL will spill over the entrance sand berm and drain to the ocean. The force of the backed up water then quickly scours an entrance channel through the beach and reopens the ICOLL to the ocean. When ICOLLs are open they become tidal with seawater moving into and out of the estuary with the daily tidal cycle. ICOLLs close when the ocean waves and tides pus
