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Carrabungla (Ca)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Carrabungla- geoArea: 169 sq. km (0.9%)

This land system occurs mainly on a variety of acidic, volcanic rocks, including the Wellington Rhyolites and the Snowy River Volcanics. The terrain is mountainous with steep, rocky slopes and a ridge-and-ravine topography. In these respects the land is similar to Elizabeth land system, but Carrabungla occurs where it is much drier, mostly at lower elevations. Small levees and alluvial flats, similar to those in Walnut land system. occur occasionally along a few major streams, notably Wilkinson Creek.

The shallow soils reflect a combination of dry climate, steep slopes and parent materials that are resistant to weathering. Leaching of bases has produced moderately-acidic soils. Surface soils have a crumb structure while the subsoils are often apedal.

The vegetation is mainly open forest II, often shrubby with sparse ground cover. Forests with slightly denser understoreys occur where moisture supply is greater. due to altitude, aspect or protection by adjacent slopes.
A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Carrabungla- image
A steep rocky slope with drier vegetation and patches of bare earth and litter characteristic of Carrabungla land system.

CLIMATE
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.): May - September
    Rainfall < potential evapotranspiration: December – February
GEOLOGY
Age, lithology

    Devonian rhyolites, rhyodacites (Wellington Rhyolites, Snowy River Volcanics); minor Silurian intercalated siltstones, conglomerates, sandstones and basalts
PHYSIOGRAPHY
Landscape
Elevation range (m)
Relative relief (m)
Drainage pattern
Drainage density (km/km2)

    Steep mountains with ridge-and-ravine topography

    220 - 1000
    140 - 600
    Dendritic
    1.4
PRESENT LAND USE
    Mostly uncleared: hardwood forestry (minor timber products); apiculture (very limited); bush grazing of cattle (very limited)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Carrabungla- geoA study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Carrabungla- graph

LAND COMPONENT
Percentage of land system
Diagnostic features
1
85
Slopes with very dry forest
2
15
Slopes with more vigorous forest, mostly on protected upper slopes
PHYSIOGRAPHY
Slope %, typical and (range)
Slope shape
30 - 40, (20 - 80)
Straight but uneven
30 - 40, (20 - 50)
Straight
SOIL
Parent material
Mainly rhyolite and rhyodacite
Mainly rhyolite and rhyodacite
Description
Dark brown sandy loam to sandy clay loam grading into dark reddish brown or brown sandy clay loam or clay; generally stony. Somewhat shallow
Dark greyish brown to black loam to sandy clay loam grading into dark reddish brown or brown sandy clay loam or clay loam; generally stony, somewhat shallow
Classification
Brown Earths, Lithosols
Um l.42, Um4.23; also Um5.51, Gn2.81, Gn3.51
Brown Earths, Lithosols
Um4.13. Um5.52. Uc6.14
Surface texture
Sandy loam to sandy clay loam
Loam to sandy clay loam
Surface consistence
Soft to slightly hard when dry, friable when moist
Soft when dry, friable when moist
Depth (m)
0.3 - 1.2
0.5 - 1.5
Nutrient status
Low to moderate
Low to moderate
Available soil water capacity
Low to moderate
Moderate
Perviousness to water
Moderate
Rapid
Drainage
Good
Good
Exposed stone (%)
10 - 80
0 - 20
Sampled profile number
12
-
NATIVE VEGETATION
Structure of vegetation and
characteristic species of
dominant stratum
(+ Predominant species)

Open forest II, sometimes shrubby:

Mixed forests with composition and predominant species variable
(one of which usually predominant), E. mannifera, E. goniocalyx,
elevations. E. pauciflora: Xanthorrhoea

Open forest II, III, often shrubby:

including E. dives, E. sieberi, E. macrorhyncha. E. consideniana
E. polyanthemos, E. rubida, E. baxteri, E. muellerana and, at higher
australis occurs occasionally

Disturbance
Affected process and trend
Primary resultant deterioration
Casual activities
Primary off-site process
Form
Susceptibility of components
Incidence with components
    Alteration of vegetation:
    — reduction in leaf area, rooting depth and/or perenniality
    Reduced transpiration, resulting in increased deep percolation.
    Nutrient loss
Not determinedNot determinedRemoval of trees
    Increased movement of
    water to groundwater;
    increased base-flow of
    streams
    Increased exposure of surface soil
    Increased overland flow and soil detachment
    Sheet and rill erosion
1.2; highNot determinedClearing, logging,
burning, road building
and other earth-moving
activities
    Increased flash flows
    and sediment load.
    Increased physical pressure on soil
    Increased compaction

    With

    reduced infiltration
    Structure decline



    Sheet and rill erosion
12; low - moderate



1,2; high
Not determined


Not determined
Loss of organic matter from topsoil


As for sheet and rill
erosion above
    -



    Increased flash flows
    Increased soil disruption
    Increased soil break-up
    Gully erosion
1.2; moderateNot determinedAs for sheet and rill
erosion above
    Increased sediment load.
Comments: No observations of deterioration
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