COASTAL LAGOON ENTRANCE DYNAMICS

Resumen

The coastline of New South Wales (NSW), Australia features numerous lakes and lagoons . The ocean entrances of the lakes tend to be continuously open to the sea. The lagoons, however, experience only intermittent periods of ocean influence following breakouts across the beach. Although the lagoons and their catchments vary markedly in size and overall geometry their hydraulic behaviour is remarkably similar. This is particularly true of their entrance dynamics. The lagoons, which are the subject of this paper, were formed during the Holocene sea level rise in embayments where the onshore movement of sand impounded small estuaries behind the coastal sand barriers (Roy 1984). They are generally 1 to 2m deep, have a water surface area of between 3 and 300 ha and are located in catchments ranging in size from 5 to 40 km''.