Swan Coastal Plain

The Swan-Canning River System occupies 2126 square kilometres out of a total catchment of approximately 141,000 square kilometres. The Swan and Canning rivers flow through the heart of metropolitan Perth, a city of more than 1.4 million people.

The Swan Coastal Plain around Perth is more than 100,000 years old. During this time much of the original sediment has been highly leached. The surface sediments now consist mainly of sand with poor nutrient-binding abilities. The coastal plain is quite flat and therefore its watercourses flow relatively slowly.