|Alluvial plains developed in the lower reaches of the Dandenong, Cardinia and Tynong Creeks and the Bunyip, Lang Lang and Bass Rivers. The drainage eventually flowed into swamps and lagoons, described under Section 7.1.3. Since the drainage of the swamps, drains now confine the flows of all these rivers and streams.|
The original vegetation on the plains was mostly comprised of swamp scrub, but some areas would have been swampy grasslands and grasslands, some of which may have become invaded by swamp scrub immediately after the displacement of the Koori population. The present climate is humid to sub-humid with rainfall generally well distributed throughout the year. The grazing of dairy cattle has been an important industry in the past, but have mainly been replaced by beef cattle. Most of the alluvial plains have texture contrast soils (mostly Kurosols) but there are areas of grey clays (Vertosols).