Soil/Landform Unit 193

Gently undulating depositional plain west of Murgheboluc

Area:

134 ha

0.01% of CMA region

A gently undulating plain east of Inverleigh is a member of an

complex within the Western Plains. The unit is characterised by a combination of terraces, billabongs, drainage depressions and streambanks. Neogene sedimentary plains to the north (Unit

b) and the Barwon River to the south surround this small single entity unit. The remnant vegetation class of the unit is Plains Grassy Woodland with majestic

Eucalyptus camaldulensis

lining these drainage depressions, drainage lines and billabongs. The soils are

sodic

brown and red texture contrast soils (

Sodosols

) on the higher older terraces, more friable gradational soils (

Dermosols

) on the younger lower terraces, and cracking clays (

Vertosols

) in the depressions. Rainfall is relatively low in this area. Land use is grazing with some cropping, as well as residential use. The terraces have moderate to slow site drainage, the sodic upper terraces may have structure problems as well as susceptibilities to

compaction

and sheet erosion. The lower areas are susceptible to waterlogging.

The short steep slopes and scarps are particularly vulnerable to water erosion (gully and tunnel, sheet and rill)

Component	1	2	3	4
Proportion of soil-landform unit	45%	35%	5%	15%
CLIMATE Rainfall (mm)	Annual: 530
Temperature (^oC)	Minimum 9, Maximum 20
Precipitation less than potential evapotranspiration	September–April
GEOLOGY Age and lithology	Quaternary alluvium - clay, sand and gravel
Geomorphology	6.2.5 Alluvium, alluvial terraces, floodplains and coastal plains of the Sedimentary Western Plains
LANDUSE	Uncleared: Nature conservation; passive recreation Cleared: Residential, grazing, some cropping
TOPOGRAPHY Landscape	Gently undulating plain
Elevation range (m)	36–42
Local relief (m)	5
Drainage pattern	Dendritic
Drainage density (km/km²)	2.4
Landform	Terrace 2	Terrace 1	Depressions and billabongs in Terrace 1	River channel bed, banks and levees
Landform element	Higher terraces	Lower terraces	Low-lying wet areas
Slope and range (%)	0–3	0–2	0–2	0–2
Slope shape	Straight	Straight	Concave	Concave
NATIVE VEGETATION Ecological Vegetation Class	Plains Grassy Woodland (2.8%)
Dominant species	E. camaldulensis
SOIL Parent material	Unconsolidated gravel, sand, silt and clay	Unconsolidated gravel, sand, silt and clay	Unconsolidated gravel, sand, silt and clay	Unconsolidated gravel, sand, silt and clay
Description (Corangamite Soil Group)	Red texture contrast soils, some dark texture contrast soils (32)	Dark uniform loams (34)	Dark clay soils (31)	Channel - variable, levee (11), uniform fine sands
Soil type sites	SW88, SFS20, CLRA4	SW39, CLRA15, CLRA1	CLRA15, SW37, CLRA48	CLRA7, OTR426, SW39
Surface texture	Loamy sand and sandy loam	Loam to clay loam	Clay loam to clay	Variable
Permeability	Moderate	High	Low
Depth (m)	0.5–1.0	0.2–0.8	0.8–1.5
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Overland flow can lead to minor sheet erosion on exposed soil.	Low situation affected by flooding and siltation from river, overland flow and periodic waterlogging.	Low situation affected by flooding and siltation from river, overland flow and periodic waterlogging.	Low situation affected by flooding and siltation from river, streambank erosion, overland flow and periodic waterlogging.

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