The Erskine River catchment is situated in the Otway Ranges and discharges to Loutit Bay at Lorne, Victoria. Its estuary is an Intermittently Closed and Open Lake or Lagoon (ICOLL) extending approximately I km inland from the coast. The usual water level in the estuary is set by a sand bar at the river mouth, which is subject to complete closure during dry periods.
An intense rainfall event on 15th January 2026 associated with a slow-moving storm cell caused flash flooding that scoured out the entrance bar, evacuating the sand from the bar into Loutit Bay. The base level for the estuary was temporarily lowered, lowering the water level throughout the estuary. The scour of the river mouth and fall in water level through the estuary exposed features that are rarely seen, including the remains of a nineteenth century shipwreck at the river mouth and a mid-estuary rock bar.
Geomorphic recovery was rapid. Within days of the flood, wave action had already constructed a substantial sand bar across the river mouth, influencing tidal exchange and water levels in the estuary. Within a few weeks, the naturally reconstructed sand bar had raised water levels in the estuary to pre-flood levels. Understanding the natural estuary opening and closing dynamics, as shown the response to the January 2026, flood has important implications for management of the estuary (including local flooding, drainage, geomorphology and ecology).