Soil/Landform Unit 101

The volcanic hills offer great vantage points to view the neigbouring Lake Corangamite

Area:

1812 ha

0.14% of CMA region

This unit consists of a complex of low hills between the eastern shore of Lake Corangamite and Lake Colac. Near Coragulac, these low hills consist of a suite of volcanic landforms including maars, cones and basaltic slopes. The low hills offer a magnificent example of the

Quaternary

volcanics of the Western Plains and the scenic lookout ‘Red Rock’ is a highly visited location of the Corangamite region. Soils of the hill are predominantly black gradational soils with layers of volcanic ash encountered at a depth of 30–55 cm. Friable black and red loams occur on the steep hills and rims of the maars. Mottled black texture contrast soils also occur, mainly in drainage lines and depressions. Little remnant vegetation remains on these hillslopes and crests; the two main vegetation classes being Stony Rises Herb-rich Woodland and Scoria Cone Woodland. The agricultural land use is quite variable and includes beef cattle and sheep grazing, dairy farming, cereal cropping, horticulture, viticulture and recreation. Horticulture and cereal cropping is especially prevalent on the lower slopes. Given the relatively young parent material, these soils are generally

friable

and highly productive, but are often shallow. The shallow soils tend to be susceptible to waterlogging (in wet seasons in depressions and drainage lines) and

compaction

Maars and steep eruption points are pronounced throughout the unit
	Lower slopes surrounding the low hills are mainly used for cropping and horticulture

Component	1	2	3	4
Proportion of soil-landform unit	15%	5%	30%	50%
CLIMATE Rainfall (mm)	Annual: 660
Temperature (^oC)	Minimum 8, Maximum 19
Precipitation less than potential evapotranspiration	October-March
GEOLOGY Age and lithology	Quaternary scoria and basalt
Geomorphology	6.1.1 Eruption points of the Volcanic Western Plains
LANDUSE	Uncleared areas: Nature conservation; water supply Cleared areas: Sheep and beef cattle; dairy farming; cropping; horitculture; passive and active recreation
TOPOGRAPHY Landscape	Undulating low hills
Elevation range (m)	118-273
Local relief (m)	65
Drainage pattern	Radial
Drainage density (km/km²)	0.9
Landform	Hill
Landform element	Cones/hills/tumulus	Maar	Mid slopes	Footslopes/lower slopes
Slope and range (%)	15 (10-40)	0	11 (3-25)	6 (2-15)
Slope shape	Convex	Straight	Convex	Concave
NATIVE VEGETATION Ecological Vegetation Class	Stony Rises Herb-rich Woodland (1.7%), Scoria Cone Woodland (1.2%)
SOIL Parent material	Ash and scoria	Ash and scoria	Scoria, ash and basalt	Scoria, ash and basalt
Description (Corangamite Soil Group)	Neutral black gradational soils and shallow friable loams (40/41)	Neutral black gradational soils and shallow friable loams (40/41)	Neutral black gradational soils (40/41)	Friable mottled black texture contrast soils (37) and neutral black gradational soils (40/41)
Soil type sites	SW26, SW8, SW25	SW26, SW96, SW8	SW26, SW8, SW96	SW25, SW26, SW8
Surface texture	Clay loam	Clay loam	Clay loam	Clay loam
Permeability	High	High	Moderate to high	Moderate
Depth (m)	<1	<0.7	<1	<1.5
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Friable structured soil. Soil depth may be shallow to moderately deep with limited water holding capacity. Well drained and high nutrient holding capacity. Uper soil may be acidic.	Frible structured soil. Soil depth may be shallow to moderately deep with limited water holding capacity. Well drained and high nutrient holding capacity. Upper soil may be acidic.	Friable structured soil. Soil depth may be shallow to moderately deep with limited water holding capacity. Well drained and high nutrient holding capacity. Upper soil may be acidic.	Friable structured soil. Soil depth may be only moderately deep with limited water holding capacity. Well to imperfectly drained and high nutrient holding capacity. Upper soil may be acidic. Drainage lines may be subject to waterlogging and compaction.

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