Western Port - Geography

Geography

Formerly a major river drainage system, it was inundated together with Port Phillip by the rising sea in the Holocene period; the Western Port sunkland now forms an extensive tidal bay. The waters of Western Port cover an area of 680 km² of which 270 km² are exposed as mud flats at low tide. The topography of Western Port is dominated by two large islands: French Island and Phillip Island. The coastline, including that of the islands, is some 263 km. The bay and its islands are criss-crossed by seven seismically active fault lines and experiences numerous minor earthquakes every year.

In the northern reaches, several rivers and creeks drain into the bay and flow through extensive mangroves, mudflats and sand banks before being channelled either side of French Island and into the open water in the southern reaches around Phillip Island. Several natural river paths and channels provide access for boats to the northern reaches, however, this is highly dependent on the tides and local knowledge is essential. Some of the major tributaries of Western Port are Bunyip River, Lang Lang River, Bass River, Cardinia Creek, Redbill Creek, Mosquito Creek, Brella Creek and Tankerton Creek. Until the mid 20th century, the Koo-Wee-Rup Swamp adjoined the bay in the north, covering an area of 30–40 thousand hectares, extending inland to present day Pakenham, prior to cultivation of the land by early settlers. The mangroves in the northern reaches are the only remnants of this swamp today.