Soil/Landform Unit - Sugarloaf granitic hills

North-western slopes of the Black Range near Stawell

Area: 11 413 ha

0.49% of CMA region

The eastern Black Range, south-west of Stawell (Sugarloaf granitic hills has been used to avoid confusion with the western Black Range) is part of the Dissected Western Uplands. Occupying the western end of the Western Dissected Uplands with a vale separating it from the Grampians Ranges, the granite hills are surrounded by outwash slopes and lower metasedimentary terrain of rises and plains. Steep slopes and crests (with rock outcrop) are dominant with colluvial slopes surrounding the hilly terrain. Drainage depressions and drainage lines are present with a radial drainage system extending to the Mt William Creek alluvial system. Soils are extremely shallow sandy soils (

Rudosols

) on steep slopes and areas of outcrop with yellow texture contrast soils that are sodic (

Sodosols

) on the lower slopes. Sheet and rill erosion are the major land degradation susceptibilities for this unit with wind erosion of light topsoils possible where exposed. This unit is used for grazing (sheep, beef cattle), occasional dryland cropping, quarrying (sand and gravel) and a water supply function in some areas. A variety of remnant vegetation communities have been recorded including woodland and scrub.

Looking west towards Mount William Creek from the Black Range
	Sister Rocks on the Western Highway near Stawell

Component	1	2	3	4
Proportion of soil-landform unit	20%	30%	40%	10%
CLIMATE Rainfall (mm)	Annual: 650
CLIMATE Rainfall (mm)	Annual: 650
Temperature (^oC)	Minimum 8, Maximum 19
Precipitation less than potential evapotranspiration	October–April
GEOLOGY Age and lithology	Neogene fluvial gravel, sand and silt; Cambrian marine sandstone, siltstone and shale (Glenthompson sandstone); Cambrian basalt, andesite, boninite, rhyolite, gabbro and lithics
GEOLOGY Age and lithology
Geomorphology	2.1.3 Ridges, escarpments and mountains on granitic Palaeozoic rock of the Dissected Western Uplands and 2.1.4 Hills, valley slopes and plains on granitic Palaeozoic rock of the Dissected Western Uplands
LANDUSE	Uncleared areas: water supply; nature conservation; gravel and sand extraction Cleared areas: sheep and beef cattle grazing; water supply; gravel and sand extraction
LANDUSE
TOPOGRAPHY Landscape	Granite hills
TOPOGRAPHY Landscape	Granite hills
Elevation range (m)	196–286
Local relief (m)	90
Drainage pattern	Dendritic
Drainage density (km/km²)	1.7
Landform	Colluvial footslopes		Hills
Landform element	Creek/drainage depression	Colluvial footslope	Steep hillslope/crest	Drainage line
Slope and range (%)	2 (0-3)	5 (3-10)	30 (5-65)	3 (2-5)
Slope shape	Concave	Concave	Convex	Concave
NATIVE VEGETATION Ecological Vegetation Class	Plains Grassy Woodland (36.7%), Hills Herb-rich Woodland (13.5%), Heathy Woodland (10.9%), Alluvial Terraces Herb-rich Woodland (10.5%), Other (27.9%)
NATIVE VEGETATION Ecological Vegetation Class
SOIL Parent material	Fluvial gravel, sand and silt	Colluvial gravel, sand and silt, in situ intrusive granite	In situ intrusive granite	In situ intrusive granite, fluvial gravel, sand and silt
SOIL Parent material	Fluvial gravel, sand and silt		In situ intrusive granite	In situ intrusive granite, fluvial gravel, sand and silt
Description (Corangamite Soil Group)	Sodic yellow texture contrast soils (4)	Sodic yellow texture contrast soils (4)	Yellow texture contrast soils (3)	Yellow texture contrast soils (3) and sodic yellow texture contrast soils (4)
Soil type sites	GW28, GW30	GW28, GW30	GW31, WLRA91	GW31, WLRA91, GW28
Surface texture	Clayey coarse sand to sandy clay loam	Clayey coarse sand	Silty loam (sandy)	Sandy clay loam
Permeability	Very slow	Slow	Moderate to high	Slow
Depth (m)	> 2	> 2	< 0.7	0.5-1.5
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS Critical land features, processes, forms	Sodic subsoil susceptible to gully erosion. Poor subsurface drainage, particularly on flats and depressions. Surface soils susceptible to acidification.	Light loose surface soils susceptible to wind, sheet and rill erosion in drier areas (including drier aspects). Sodic subsoil susceptible to gully erosion. Surface soils susceptible to acidification.	Light loose surface soils that may be susceptible to wind, sheet and rill erosion in drier areas (including drier aspects). Susceptible to acidification in wetter areas.	Sodic subsoil susceptible to gully erosion. Poor subsurface drainage, particularly on flats and depressions. Surface soils susceptible to acidification.

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