Soil/Landform Unit 61

Wild Dog Creek is an example of terrain that is difficult to manage due to prominent steep slopes and landslips of this landscape

Area:

76 768 ha

5.75% of CMA region

The dissected ranges of the Southern Uplands includes steeply dissected spurs and ridges in the wetter parts of the Otway Range (the largest land system in the study area). Rapid downcutting of streams following uplift of the range has been responsible for forming this rugged landscape, with many slopes more than 60% and cliffs and bluffs in the central area north of Apollo Bay. The soils are young and moderately fertile brown gradational soils. Tall open forests of

Eucalyptus regnans

reach heights approaching 100 m in the Calder River catchment, but most of the tallest trees have now been milled.

E. obliqua

and

E. cypellocarpa

are also common, while

E. viminalis

occurs in the west and

E. globulus

is found close to the coast. Pine forests cover large areas of this unit and other parts have been cleared for agriculture. The main hazards to land use are landslips and sheet erosion. Losses in organic matter and soil structure are often apparent following clearing.

Dissected hills north of Johanna
	Tree ferns and remnants of tall open forests

Component	1	2	3
Proportion of soil-landform unit	10%	80%	10%
CLIMATE Rainfall (mm)	Annual: 1100-1750, lowest January (60), highest August (170)
Temperature (^oC)	Annual: 11, lowest July (7), highest February (16)
Precipitation less than potential evapotranspiration	Temperature: less than 10^oC (av.) May-September Precipitation: less than potential evapotranspiration December-February
GEOLOGY Age and lithology	Cretaceous fluvio-volcanic sandstone, siltstone and mudstone
Geomorphology	3.1.2 Deeply dissected upland ranges of the Southern Uplands
LANDUSE	Uncleared areas: Hardwood forestry; softwood plantations; nature conservation; water supply; passive recreation Minor cleared areas: Beef cattle grazing and dairy frming on mainly improved pastures; row cropping on gentler slopes
TOPOGRAPHY Landscape	Deeply dissected hills of the Otway Range
Elevation range (m)	90-560
Local relief (m)	165
Drainage pattern	Trellis pattern with isolated radial areas
Drainage density (km/km²)	3.1
Landform	Hills
Landform element	Crest	Upper and middle slope	Lower slope and drainage line
Slope and range (%)	25 (5-30)	40 (25-80)	25 (5-40)
Slope shape	Convex	Linear	Concave
NATIVE VEGETATION Structure	Tall open forest	Tall open forest	Tall open forest to tall closed forest
Dominant species	E. obliqua, E. cypellocarpa, E. regnans, E. ovata, E. globulus, E. viminalis, Acacia melanoxylon	E. regnans, E. cypellocarpa, E. obliqua, E. ovata, E. viminalis, E. globulus	E. regnans, E. obliqua, Acacia melanoxylong, Nothofagus cunninghamii, E. cypellocarpa, E. ovata, E. viminalis, E. globulus
SOIL Parent material	In situ weathered sandstone, siltstone and mudstone	In situ weathered sandstone, siltstone and mudstone	Alluvium and colluvium
Description (Corangamite Soil Group)	Brown gradational soil (7)	Brown gradational soil (7)	Brown gradational soils (7)
Soil type sites	OTR414, COF01, OTR736	OTR416, COF01	OTR428, OTR736
Surface texture	Loam	Loam	Loam
Permeability	Moderate	Moderate	High
Depth (m)	1.4	1.2	>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	High rainfall, moderate permeability and leaching plus loss of organic matter and soil structure upon disturbance lead to nutrient decline and soil compaction, also sheet erosion on steeper slopes.	Clay subsoils on steep slopes subject to periodic saturation are pone to landslips. Steep slopes are prone to sheet and rill erosion. High rainfall, moderate permeability and leaching plus loss of organic matter and soil structure upon disturbance lead to nutrient decline and soil compaction.	Rapid surface runoff from adjacent hills lead to scour gullying, siltation and flooding. High rainfall, high permeability and leaching plus loss of organic matter and soil structure upon disturbance lead to nutrient decline and soil compaction.

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