This former swampland is occupied by Bangholme, Braeside, Carrum Downs, Chelsea Heights, and Keysborough. Parts of Aspendale, Patterson Lakes and Seaford are also on the former swamp.
Carrum Swamp's waters came from the Dandenong Creek (with headwaters in the moist Dandenong Ranges, and the Eumemmerring Creek with headwaters at Narre Warren. The swamp occupied 5260 ha, extending almost from Mordialloc to Frankston, and had a water catchment of 737 sq km. In its natural state it was covered with dense ti-tree, and it had ineffective outlets to Port Phillip Bay by the Mordialloc Creek and the Kananook Creek. The land was, however, useful for Summer pasture, and sections were purchased in the 1850s.
An early squatting party in the area called its station Garen Gam, thought to be Aboriginal for boomerang. Another rendering of the Aboriginal words is Karrum Karrum. An 1864 map made by the Hydrographic Office called the swamp Garrum, which would also be a probable forerunner of Carrum. An alternative but unlikely source of the name is an ancient English settlement called Carrum in Arthurian legends.
In 1868 the Dandenong Shire Council made channels across the swamp to carry the creek waters to the Mordialloc and Kananook Creeks, resulting in some land being taken for grazing and cultivation. In 1878 the ‘Patterson River’ was cut through the swamp and coastal sand to Port Phillip Bay as a further drainage measure. The ‘River’ begins roughly where the Dandenong and Eumemmerring Creeks intersect at Bangholme. Flooding in 1889 overcame the channels and the artificial river, and the Carrum Trust was formed to enlarge all the outlets and construct smaller channels for irrigation during dry periods. Further floods in 1923-24 resulted in enlargement of the drains by the State Rivers and Water Supply Commission which partly superseded the Trust in 1910. The Trust was abolished in 1936, and the Dandenong Valley Authority took over responsibility in 1966. The Authority oversaw the construction of the Patterson Lakes water-sport complex near the mouth of the ‘River’ during the 1980s.
Remnants of the swamp remain at the Edithvale-Seaford Environmental Wetlands Areas.
E.J. Lupson, The Carrum Swamp lands, history of the Carrum Waterworks Trust, State Rivers and Water Supply Commission, 1940
Frank McGuire, They built a river, City of Chelsea Historical Society, c1979