The Wimmera River from Greens Creek to Natimuk (defined as the Drung alluvial plains) are characterised by backplains with flats, slopes and stream channels while the modern drainage system has prominent stream banks, channels and drainage lines. In the Horsham area these plains were referred to as representative examples of the floodplain landscape (now referred to as the Drung map unit) and occur mostly south of the Wimmera River. In the east Wimmera Survey (Badawy 1984) soils of the unit comprised the Wal Wal association. The plains receive flows from all tributaries of the upper Wimmera catchment area including Mount Cole Creek, Wimmera River, Mount William Creek and Concongella Creek. Orientated and running almost east-west for over 80 km, the plains are quite expansive (up to 5 km wide) and reflect once greater fluvial activity in the dissected western uplands. Gradients are very gentle to level with the areas prone to flooding in wet seasons. |
Soil-landform unit | Unit description | Area (km2) |
Barrabool sand plains | Sand plain | 32 |
Drung alluvial plain | Alluvial floodplain | 349 |
Horsham lake and lunettes | Lake and lunette | 2 |
Riverside level plains | Level plain | 1 |
Werrap lake-lunettes | Prior stream plains | 55 |