The underlying soils and rocks of Homebush Bay were deposited by the rivers and creeks that flowed across the area. Earliest written records describe Homebush Bay as an intertidal zone of mudflats that were inundated at high tide and vegetated by a mixture of mangroves and saltmarsh plant communities. Haslams Creek floodplain is described as supporting saltmarsh communities and fresh water wetland species.

After European colonisation the area began to change dramatically. Forested land was cleared for farming and mudflats were reclaimed for industrial use. Haslams Creek was straightened and converted into a stormwater canal and much of the area was also used to dump industrial, commercial and domestic waste.