The narrow tidal entrance to the Tasman Sea of the South Pacific Ocean is located at Windang. Before 2007 Lake Illawarra was frequently closed to the sea. The lake system received large amounts of nutrient and sediment from the catchment which tended to remain within the lake. Water levels within the lake also fluctuated greatly, affecting the local flora species. In July 2007 the Lake Illawarra Authority completed works on training the entrance of the lake to create a permanent opening to the sea.