Soil/Landform Unit 203

The residual steep granitic hills of the You Yangs is well defined in the relatively planar surface of the Western Plains

Area: 732 ha

0.05% of CMA region

The You Yangs are very steep hills almost entirely composed of granitic bedrock on the eastern boundary of the Corangamite catchment. The very steep hills are characterised by areas of prominent rock outcrop and gentler rock-free lower slopes. Within the Western Plains, these granitic hills are characterised by deep uniform sands on the upper slopes and

acidic

mottled

yellow

duplex

soils on the lower slopes. Remnant vegetation includes Hills Herb-rich Woodland and Granitic Hills Woodland. Land use is restricted to grazing on native or introduced pastures due to the steepness and soil qualities such as low available water holding capacity and ready

leaching

of nutrients. The sand surfaces are prone to sheet erosion by water and wind. The permeable nature of these soils combined with steep slopes may provide a potential for landslips. Gully erosion occurs to a minor extent and can be difficult to control due to the steepness and inaccessibility of the drainage depressions.

Steep slopes and low water holding capacity of soils has restricted the land use mainly to grazing, nature walking and sport and recreation
	Lower colluvial slopes of Unit 16 surround the You Yangs

Component	1	2	3	4
Proportion of soil-landform unit	10%	20%	30%	40%
CLIMATE Rainfall (mm)	Annual: 530
Temperature (^oC)	Minimum 9, Maximum 19
Precipitation less than potential evapotranspiration	October–April
GEOLOGY Age and lithology	Devonian granitic intrusive and minor Neogene fluvial sediments
Geomorphology	6.3.1 Granitic hill inliers of the Western Plains
LANDUSE	Uncleared: Nature conservation; sport and recreation; water supply Cleared: Sheep and cattle grazing; sand and granite extraction; severely disturbed
TOPOGRAPHY Landscape	Very steep hills of the You Yangs
Elevation range (m)	52–331
Local relief (m)	170
Drainage pattern	Dendritic
Drainage density (km/km²)	1.1
Landform	Very steep hills
Landform element	Crest and rock outcrops	Steep upper slope	Mid slope	Lower slope
Slope and range (%)	5 (1–12)	20 (10–40)	10 (5–20)	6 (3–15)
Slope shape	Convex	Convex	Concave	Straight
NATIVE VEGETATION Ecological Vegetation Class	Hills Herb-rich Woodland (7.9%), Granitic Hills Woodland (7.7%)
SOIL Parent material	In situ granite	In situ granite	In situ granite	In situ granite and colluvium
Description (Corangamite Soil Group)	Shallow and deep sand soils (4)	Deep sand soils (4)	Acidic mottled yellow texture contrast soils (3)	Acidic mottled yellow texture contrast soils (2)
Soil type sites	BD8, MM236	BD8, MM236	MM5150	MM162, MM411
Surface texture	Loamy sand	Loamy sand	Coarse sandy clay loam	Coarse sandy clay loam
Permeability	Very high	High	High to moderate	moderate
Depth (m)	< 1	< 1	< 1.5	<2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Rocky, sandy with low water holding capacity and nutrient holding capacity in surface and (bleached) subsurface soil. Generally hardsetting, occasionally loose. Rapid site drainage. Susceptibility to nutrient decline, sheet and rill erosion.	Some rock, sandy with low water holding capacity and nutrient holding capacity in surface and (bleached) subsurface soil. Generally hardsetting, occasionally loose. Very rapid site drainage. Susceptibility to nutrient decline, sheet and rill erosion, possibly gully erosion.	Some stone, coarse sand component. Texture contrast, low water holding capacity and nutrient holding capacity in surface and (bleached) subsurface soil, high in subsoil. Generally hardsetting. Rapid site drainage. Susceptibility to nutrient decline, sheet and rill erosion, possibly gully erosion.	Coarse sand component. Texture contrast, low water holding capacity and nutrient holding capacity in surface and (bleached) subsurface soil, high in subsoil. Generally hardsetting. Moderately rapid site drainage. Susceptibility to nutrient decline, sheet and rill erosion, possibly gully erosion.

Page top