Soil/Landform Unit 201

Swamps, flats and minor associated lunettes heading south-east towards Leslie Manor near Lake Corangamite

Area:

1129 ha

0.08% of CMA region

This unit consists of swamps, lakes and associated lunettes as part of an alluvial/aeolian complex on the north-west side of Lake Corangamite. This succession of lakes, swamps, plains and minor lunettes hosts a range of vegetation communities including Plains Grassland/Plains Grassy Woodland Mosaic, Grassy Woodland and Plains Sedgy Wetland. These small individual units are located within an alluvial area that drains directly into Lake Corangamite’s western shore. The unit has black gradational soils and some self-mulching grey cracking clays on the lunettes and flat plains. The soils are friable, strongly structured and productive, and generally deep with moderately rapid site drainage and no stone. The swamps have alkaline black or grey cracking clays. Rainfall is sufficient to influence grazing intensity (for dairying or beef/sheep production) and is slightly drier here than its associated unit to the south (Unit 150). Waterlogging and soil compaction are possible constraints in wet seasons for these soils.

Flat plains of swamps and former swamps are heavily grazed over the drier seasons by beef cattle and sheep
	Long lunette bordering a vast plain near Lake Terangpom

Component	1	2
Proportion of soil-landform unit	70%	30%
CLIMATE Rainfall (mm)	Annual: 630
Temperature (^oC)	Minimum 8, Maximum 19
Precipitation less than potential evapotranspiration	October–March
GEOLOGY Age and lithology	Quaternary fluvial clay, silt and sand
Geomorphology	6.2.5 Alluvium, alluvial terraces, floodplains and coastal plains of the Sedimentary Western Plains
LANDUSE	Uncleared areas: Water supply; nature conservation Cleared areas: Sheep and beef cattle grazing; dairy farming; water supply
TOPOGRAPHY Landscape	Swamps and flats
Elevation range (m)	120–140
Local relief (m)	1–2
Drainage pattern	Centripetal–parallel
Drainage density (km/km²)	3.0
Landform	Plains and swamps
Landform element	Flat plains	Swamps
Slope and range (%)	1 (0–2)	0
Slope shape	Straight	Straight
NATIVE VEGETATION Ecological Vegetation Class	Plains Grassland / Plains Grassy Woodland Mosaic (1.8%), Grassy Woodland (1.3%), Plains Sedgy Wetland (1.2%)
SOIL Parent material	Clay, silt and sand	Clay, silt and sand
Description (Corangamite Soil Group)	Mottled black texture contrast soils (32/33) and black or grey cracking clay soils (31)	Alkaline black or grey cracking clays (31)
Soil type sites	SW67, SW2, SW38	SW88, SW37, CLRA48
Surface texture	Clay loam to light clay	Light clay
Permeability	Low	Very low
Depth (m)	>2	>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Friable, often self-mulching surface soils. Expansive clays in texture contrast subsoil as well as clay soils. Can be seasonally waterlogged with poor drainage. Deep soils with high water holding capacity.	Friable, often self-mulching surface soils. Expansive clays in texture contrast subsoil as well as clay soils. Can be seasonally waterlogged with poor drainage. Deep soils with high water holding capacity.

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