3.3.4 Terraces and floodplains (Aire River, Barham, Birregurra, Carlisle and Gellibrand Rivers, Fosters Creek, Upper Bass, Lang Lang, Tarwin, Morwell and Tarago, Birregurra Rivers)

3. Southern Uplands (SU)
3.3 Very low relief (very low elevation, generally less than 100 m)

Alluvial flats and alluvial terraces have formed in the wide valley floors at the base of the rolling hills. The wide floodplain of the Barwon River from Gerangamete to Birregurra has developed in response to the changes in base levels associated with the periodic damming of the river by Newer Quaternary Volcanic basalt flows around Winchelsea and the fluctuating sea levels of the Quaternary.

Associated soil types are gradational (Dermosols) (often grey or dark) soils and sands over clay (Chromosols).

Upper reaches within the Hoddle, Strzelecki and Ballok Ranges

Narrow valleys, steep and stepped fast flowing streams, beds often expose underlying Cretaceous sediments. Immediately adjoining the streambed there are often deep gradational soils developed on colluvium derived from upslope. As they are protected from strong winds, are shaded and moist or wet for prolonged periods, they supported cool temperate rainforest in the past. In areas where forest harvesting is still carried out, these areas are subject to clearing controls to protect remaining areas of rainforest. In agricultural areas the stream banks are steep sided and the streams themselves are prone to bed and bank erosion.

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