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Wonnangatta (Wa)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Wonnangatta- geoArea: 1008 sq. km (5.0%)

This extensive land system occurs on the hilly terrain with Ordovician, Devonian and Silurian sediments in the central and eastern parts of the East Victorian Uplands. The prominent ridge-and-ravine topography is characterised by moderately long, steep slopes, rock outcrop and active soil creep. Levees and alluvial flats similar to, though smaller than, those mapped in Walnut land system, occur occasionally along a few major streams, notably the Nicholson and Wonnangatta rivers. In most respects, Wonnangatta is a lower-relief version of Talbotville land system. It is similar in geology and topography to La Trobe land system but the climate is much drier.

Steep slopes, slow-weathering sedimentary rocks and a climate which is inadequate to support vigorous and dense vegetation give rise to relatively rapid rates of natural erosion and slow soil formation. Thus shallow, stony, leached and acidic soils are characteristic. The structure of the topsoils tends to be weakly developed and subsoils are often apedal. Removal of the vegetation is likely to lead to severe sheet erosion.

Shrubby open forest II predominates, with open forest III on protected sites and in some drainage corridors.
A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Wonnangatta- image
Hills with ridge-and-ravine topography and moderately long steep slopes north of Glenmaggie

Rainfall, mean (mm)
Temperature, mean (C)
Seasonal growth limitations

Annual 700 - 1200; lowest January or February (40 - 80), highest October (100 - 150)

Annual 8 - 12; lowest July (3 - 7), highest February (16 - 20)
Temperature <10C (av.): April - October
Rainfall < potential evapotranspiration: December - February; occasional winter snow
Age, lithology

Ordovician, Silurian and Devonian sandstones, siltstones and shales
Elevation range (m)
Relative relief (m)
Drainage pattern
Drainage density (km/km2)

Steep hills with ridge-and-ravine topography

80 - 520
60 - 300
PRESENT LAND USEMostly uncleared: hardwood forestry (minor timber products); apiculture; bush grazing of cattle (limited); small areas in Fairy Dell Scenic Reserve
Minor proportion cleared: grazing of beef cattle and sheep

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Wonnangatta- csA study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Wonnangatta- graph

Percentage of land system
Diagnostic features
Exposed slopes, drier forest
Protected slopes, moister forest
Isolated narrow terraces in
drainage corridors
Slope %, typical and (range)
Slope shape
25 - 30, (15 - 60)
25 - 30, (15 - 60)
Variable, (0 - 30)
Straight but uneven
Parent material
Mudstone, siltstone, sandstone and shale
Dark clay loam to sandy loam grading into similarly or heavier textured brown or reddish brown subsoil. Shallow to very shallow, stony and acidic, but tending to be deeper in component 2
Little differentiated greyish brown loamy sand to clay loam
Lithosols; some Brown Earths and Red Podzolic Soils; Wiesenboden in small seepage areas
Um4.13, Um5.51, Uc4.32, Uc1.44, Gn2.41, Gn4.34, Dr3.21, Dr3.61
Alluvial Soils
Uc1.43, Uc1.44, Um5.52
Surface texture
Clay loam to sandy loam
Loamy sand to clay loam
Surface consistence
Slightly hard when dry, friable when moist
Varies with texture
Depth (m)
Commonly <0.7, deeper pockets
Nutrient status
Available soil water capacity
Low to moderate
Low to moderate
Perviousness to water
Moderate to rapid
Varies from somewhat poor to good
Exposed stone (%)
5 - 80
Sampled profile number
Structure of vegetation and
characteristic species of
dominant stratum
(+ Predominant species)
Mainly shrubby open forest II, occasionally grassy open woodland: Mixed forests including — E. sieberi, E. macrorhyncha, E. goniocalyx, E. dives, E. globoidea (one of these usually predominant), E. polyanthemos, E. radiata, E. cypellocarpa, E. sideroxylon
Shrubby open forest III: E. muellerana+ or E. obliqua+ or, on upper slopes, E. sieberi+; E. cypellocarpa, E. globulus, E. sideroxylon commonly associated
Occasionally closed forest II of Acmena smithii, climbers, ferns and epiphytes in drainage gullies
Mainly shrubby open forest II, III: E. bridgesiana+ and/or E. viminalis+, sometimes with E. radiata Rarely closed forest II: Acmena smithii, climbers, ferns and epiphytes

Affected process and trend
Primary resultant deterioration
Causal activities
Primary off-site process
Susceptibility of
Incidence within
Alteration of vegetation:

— reduction in leaf area, rooting depth and/or perenniality

— reduction in density of tree roots
Reduced transpiration,
resulting in:

a) increased deep

b) increased regolith

Decreased root-binding

Nutrient loss

Soil creep

Soil creep

Not determined

1; moderate
2; moderate – high

1; moderate
2; moderate - high

Not determined

Common: on steep slopes

Common: on steep slopes

Removal of trees

Accelerated by major disturbance of native vegetation

Accelerated by major disturbance of native vegetation

Increased movement of water to groundwater; increased base-flow of streams

Increased sediment load

Increased sediment load

Increased exposure of surface soilIncreased overland flow and soil detachmentSheet and rill erosion1; moderate - high
2; moderate
CommonClearing, logging, burning, overgrazing, road and dam building and other earth-moving activities, trafficking by stock.Increased flash flows and sediment load.
Increased physical pressure on soilIncreased compaction


Reduced infiltration
Structure decline

Sheet and rill erosion
1; low
2; moderate

1; moderate - high
2; moderate

Increased trafficking, cultivation, overgrazing, export of organic matter

As for sheet and rill
erosion above

Increased flash flows
Increased soil disruptionIncreased soil break-upGully erosion

Tunnel erosion

Streambank erosion
1,2; moderate

1; moderate on colluvial

3; high
Common: locally severe


As for sheet and rill erosion above

As for sheet and rill erosion above

As for sheet and rill erosion above
Increased sediment load and turbidity of streams.

Increased sediment load and turbidity of streams.

Increased sediment load and turbidity of streams.
Comments: Severe tunnel erosion occurs near Lake Glenmaggie
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