Soil/Landform Unit 89

Landform Unit Description

Unit 89 image a
Dissected hills of the remnant ferrubinised plateau near Anglesea (top left is the township of Anglesea)
      Area: 8371 ha
      0.63% of CMA region

      Stretching inland from the coast between Bells Beach and Moggs Creek lies a dissected plain of Paleogene sediments. Long straight slopes emanate from spurs and ridges. The coastal margins are retreating and often abut the sea as cliffs or massive landslips and earthflows.

      The parent material is variable, ranging from ferruginised sediments on the ridges to relatively unweathered alluvium in the drainage lines. Thus the soils are particularly variable.

      In general, plant nutrient levels are low and surface horizons are weakly structured. Plant communities are mainly open forests less than 15 m in height; the height decreases towards the coast under the influence of salt-bearing winds. The area is highly regarded for its diversity of flora. Some parts have been cleared for agriculture. The main hazards to land use are gully erosion and sheet erosion.
Unit 89 geomorphology

Unit 89 image b
Long slopes retreating to coastal margins with steep cliffs		Unit 89 cross section

Unit 89 graph
Unit 89 image c
Vegetation of the remnant plateau

Component
1
2
3
4
5
6
7
Proportion of soil-landform unit
25%
5%
10%
30%
25%
2%
3%
CLIMATE
Rainfall (mm)

Annual: 600-800, lowest January (35), highest August (80)
Temperature (oC)
Annual: 14, lowest July (9), highest February (17)
Seasonal growth limitations
Temperature: less than 10oC (av.) july
Precipitation: less than potential evapotranspiration mid October-early April
GEOLOGY
Age and lithology

High variable Paleogene sediments consisting mainly of unconsolidated clayey silt, sand, gravel, tuff, tuff breccia also groundwater ironstone and sandstone
Geomorphology
LANDUSE
Uncleared areas: Nature conservation; active and passive recreation; landscape conservation; gravel extraction
Cleared areas: Beef cattle grazing on mainly unimproved pastures; residential; active recreation
TOPOGRAPHY
Landscape

Moderately dissected hills lying below and on the seaward side of the ferruginised plateau
Elevation range (m)
0-195
Local relief (m)
50
Drainage pattern
Rectangular
Drainage density (km/km2)
2.7
Landform
Hills
Landform element
Exposed coastal slope
Slope and crest
Lower slope and drainage line
Middle slope
Upper slope and crest
Steep slope
Landslip
Slope and range (%)
20 (5-45)
9 (5-15)
8 (1-15)
15 (5-35)
10 (1-20)
45 (25-55)
(5-90)
Slope shape
Linear/irregular
Linear
Concave
Convex
Convex
Linear
Irregular
NATIVE VEGETATION
Structure

Open forest

Open forest

Low woodland (variable)

Open forest

Open forest

Open forest

Tall woodland
Dominant species
E. obliqua, Casuarina stricta,
E. sideroxylon
E. viminalis, E. radiata,
E. baxteri
E. sideroxylon, E. obliqua
E. sideroxylon, E. obliqua
E. obliqua, E. sideroxylon,
E. baxteri
E. obliqua, E. baxteri,
E. sideroxylon
E. sideroxylon, E. obliqua,
Melaleuca lanceolata,
Casuarina stricta
SOIL
Parent material

Calcareous sand, clay, silt, sand and gravel

Sand and gravel

Clay, silt and gravel

Clay, silt and sand, sandstone

Deeply weathered clay, silt and sand

Lateritic ironstone, sandstone

Clay, silt and sand; some aeolian sand
Description
(Corangamite Soil Group)
Variable sodic texture contrast soils (27)
Grey sand soils (29)
Yellow-brown sodic texture contrast soils, coarse structure (27, 14)
Yellow-brown texture contrast soils, coarse structure (27, 15)
Mottled brown, grey, yellow and red texture contrast soils (27, 13)
Stony red gradational soils (29)
Variable sodic texture contrast soils (27)
Soil type sites
-
OTR742
OTR492, OTR744
-
-
Surface texture
Sandy loam
Loamy sand
Fine sandy loam
Fine sandy loam
Sandy loam
Sandy loam
Sandy loam
Permeability
Moderate
Very high
Very low
Very low
Moderate
Very high
Moderate
Depth (m)
>2
>2
>2
>2
>2
0.2
>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS
Native vegetation is sensitive to salt pruning and disturbance. Highly dispersible soils on steep slopes are prone to sheet erosion, gully and tunnel erosion.
Very low inherent fertility and high permeability lead to nutrient decline.
Sodic, highly dispersible subsoils are prone to gully and tunnel erosion.
Highly dispersible soils are prone to gully and tunnel erosion. Weakly structured surface soils over slowly permeable subsoils on steep slopes are prone to sheet erosion.
Low inherent fertility, phosphorus fixation and leaching of permeable A horizons lead to nutrient decline.
Stony shallow soils with low organic content, weak structure and low waterholding capacity on steep slopes are prone to sheet erosion.
Native vegetation is sensitive to salt pruning and disturbance. Marine under-cutting of highly dispersible soils maintains active landslips and earth flows.
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