Soil/Landform Unit 64

Steep southerly facing slopes that are prone to landslips at the junction of the Great Ocean Road and Wild Dog Creek

Area:

20 871 ha

1.56% of CMA region

From Cinema Point to Moonlight Head, much of the coastline consists of steep slopes, coastal cliffs and rocky shore platforms. These coastal margins of the range have a milder maritime climate than those areas further inland, and receive a lower rainfall. Inland from the coast the topography consists of steeply dissected spurs and ridges with cliffs and waterfalls. The steepest slopes have shallow stony soils with areas of rock outcrop. Most slopes, however, have moderately deep texture contrast soils. On inland slopes with a southerly aspect, no strong profile differentiation has occurred and profiles are gradational. Tall open forests, with understorey species such as

Bedfordia salicina

Olearia

spp. and

Pomaderis

spp., occupy these sites. On the texture contrast soils the trees are shorter with a more open understorey. Large tracts of this unit have been cleared and dairy farming is a major land use. The steep slopes and deep valleys create severe management problems. The coastal areas between Cinema Point and Apollo Bay have been popular for residential development. Landslips are very common and sheet erosion has been widespread.

Cleared upper crests and slopes
	Drainage line at the base to steep to precipitous slopes

Component	1	2	3	4	5	6
Proportion of soil-landform unit	7%	8%	35%	5%	35%	10%
CLIMATE Rainfall (mm)	Annual: 850-1200, lowest January (45), highest August (120)
Temperature (^oC)	Annual: 13, lowest July (9), highest February (17)
Seasonal growth limitations	Temperature: less than 10^oC (av.) July Precipitation: less than potential evapotanspiration mid November - mid March
GEOLOGY Age and lithology	Cretaceous fluvio-volcanic sandstone and conglomerate, minor Paleogene marine marl
Geomorphology	3.1.2 Deeply dissected upland ranges of the Southern Uplands
LANDUSE	Uncleared areas: Hardwood forestry for sawlogs, posts and poles; softwood plantations; nature conservation; active and passive recreation; landscape conservation; water supply Minor cleared areas: Dairy farming and beef cattle grazing on mainly unimproved pastures, residential
TOPOGRAPHY Landscape	Deeply dissected hills of the Otway Range
Elevation range (m)	0-400
Local relief (m)	150
Drainage pattern	Dendritic with some radial areas
Drainage density (km/km²)	4.0
Landform	Coastal cliffs			Hills
Landform element	Steep lower slope	Upper gentler slope	North and west facing slopes and upper slope	Lower slope and drainage line	South and east facing slopes	Steepest slope
Slope and range (%)	60 (30-75)	30 (15-45)	45 (5-55)	20 (1-35)	45 (5-65)	60 (20-70)
Slope shape	Linear	Convex	Linear	Concave	Linear	Linear
NATIVE VEGETATION Structure	Open scrub	Woodland	Open forest	Tall open forest	Tall open forest	Woodland
Dominant species	Casuarina stricta, Cassinia aculeata, E. obliqua, Alyxia buxifolia, Leucopogon parviflorus	E. obliqua, E. globulus, E. viminalis	E. obliqua, E. sideroxylong, E. radiata, E. cypellocarpa, E. globulus	E. ovata, E. globulus, E. cypellocarpa, Acacia melanoxylon	E. cypellocarpa, E. globulus, E. obliqua, E. ovata	E. radiata E. sideroxylong, E. cypellocarpa, occasionally E. viminalis, E. globulus
SOIL Parent material	Colluvium	In situ weathered sandstone and conglomerate	In situ weathered sandstone and conglomerate	Alluvium	In situ weathered sandstone and conglomerate	Colluvium
Description (Corangamite Soil Group)	Stony brown gradational soils (7)	Brown texture contrast soils (6)	Brown texture contrast soils (6)	Brown gradational soils, weak structure (34)	Brown gradational soils (7)	Stony brown gradational soils (7)
Soil type sites	OTR732	OTR424	OTR424	CLRA15, OTR607, OTR733	OTR414, COF01, OTR736	OTR732
Surface texture	Fine sandy loam	Fine sandy clay loam	Fine sandy clay loam	Silty loam	Fine sandy clay loam	Fine sandy loam
Permeability	Very high	Moderate	Moderate	High	High	Very high
Depth (m)	0-3	0.9	0.9	>2	0.9	0.5
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Native vegetation is sensitive to salt pruning and disturbance. Dispersible soils on steep slopes are prone to sheet erosion. Marine undercutting and saturation of soils lead to landlips.	Native vegetation is sensitive to disturbance and to salt pruning. Dispersible soils on moderate slopes are prone to sheet erosion. Periodic saturation of dispersible clay subsoils leads to landslips and slumping of road batters.	Dry aspect, steep slopes and weakly structured surfaces lead to sheet erosion. Clay subsoils on steep slopes subject to periodic saturation are prone to landslips.	Weakly structured soils receiving runoff are prone to scour gullying, siltation, flooding, and compaction of surface structure.	Steep slopes and weakly structured surfaces lead to sheet erosion. Clay subsoils on steep slopes subject to periodic saturation are prone to landslips.	Stony shallow soils of weak structure slopes are prone to capacity on steep and low water holding sheet erosion and landslides.

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