Boon wurrung people gave the name Karrum Karrum to the flood-prone area that extended from Mordialloc to Kananook creeks, separated from Port Phillip Bay by a long, narrow sandy ridge. The swamp was fed by the Dandenong, Eumemmerring and smaller creeks originating in the Dandenong Ranges and drained inadequately into the bay by the Mordialloc and Kananook creeks. Boon wurrung people used it as a rich source of eels and wildfowl, but apart from hunting parties and travellers forced to find a route to the Mornington Peninsula, early Europeans avoided settling on the swamp. In 1861 the swamp was gazetted as the Mordialloc Farmers' Common, but 10 years later it was offered for sale by selection. Many of the selectors ran cattle on their land, but the rich black soil also promised to be valuable for cereal and potato crops. Unfortunately, few selectors could build on or improve their flood-prone properties.
The Lands Department prepared a scheme, partially carried out by the Dandenong Roads Board, to drain the swamp by constructing two main channels to carry the waters from the Dandenong and Eumemmerring creeks to the Mordialloc and Kananook creeks. When this proved inadequate, the Minister for Public Lands, J.B. Patterson, recommended in 1878 that a canal be cut directly to the sea. Patterson's Cut, later called Patterson River, was constructed in 1879, and a more permanent bridge replaced an earlier one in 1881. Despite Patterson's Cut, flooding of the swampland and surrounding districts continued periodically because of the low level of the land. The Carrum Trust, constituted in the 1890s, carried out enlargement of the drain and further work was carried out with unemployment relief labour during the 1890s and 1930s depressions. Nevertheless, even in the 1920s and 1930s and again in 1952, homes in the City of Chelsea were inundated during floods. During the 1950s and 1960s, further work, such as the installation of floodgates and pumps and the raising of the height of outfall drains, effectively protected local areas from flooding. In the 1890s the swampland had been sold off in small allotments for closer settlement farming, particularly for vegetables and cereals. After World War II, suburbanisation spread inland from the coast and the railway line. Significant areas, however, such as the Edithvale Wetlands and the Seaford Swamp, remain as swampland, administered by the Dandenong Valley Authority and used as sanctuaries for bird life.