Your gateway to a wide range of natural resources information and associated maps

Victorian Resources Online

Dargo (Do)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Dargo- geoArea: 380 sq. km (1.9%)

The plutonic and related gneissic rocks of the Dargo land system have been deeply weathered and eroded to levels below the surrounding, resistant, metamorphic or sedimentary rocks.

The deep weathering may have occurred as long ago as the Mesozoic. The surrounding, resistant aureoles have restricted incision by the outflowing streams and this has allowed storage of colluvium on the lower slopes and of alluvium in valley floors. The larger occurrences of which are mapped in Walnut land system. Topography is hilly to gently undulating.
A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Dargo- image
Rounded hills and undulating footslopes, mostly cleared for grazing.

The coarsely-crystalline plutonic rocks weather relatively easily to form soil. The texture of which depends on the mineral composition and the degree of weathering of the parent rock. The granitic rocks, which are highest in quartz and potassium feldspars, produce coarse-textured soils, whereas those highest in sodium-calcium feldspars form more clayey soils. Most soils have clay subsoils with a well-developed, blocky structure and a red colour indicating good drainage and the presence of iron oxides. On some slopes deep, light-yellowish-brown, rather sandy soils occur on lag deposits containing abundant, partially-weathered, feldspar grains. Most soils are mildly acidic to neutral.

There is a reported instance of soil salinity, however it is unlikely to he a significant hazard in the land system. Erosion is more of a hazard here.

The native vegetation, now largely cleared, appears to he mainly grassy forest II.

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

    Annual 600 - 900; lowest July (40 - 70), highest October (60 - 90)

    Annual 12 - 14; lowest July (8 - 10), highest February (19-21)
    Temperature <10C (av.): May - September
    Rainfall < potential evapotranspiration: November – March
GEOLOGY
Age, lithology
    Palaeozoic granites, granodiorites, diorites and related coarsely crystalline gneissic metamorphics; deeply weathered
PHYSIOGRAPHY
Landscape
Elevation range (m)
Relative relief (m)
Drainage pattern
Drainage density (km/km2)

    Rounded hills and undulating footslopes

    160 - 750
    80 - 180
    Dendritic
    4 – 6
PRESENT LAND USE
    Mostly cleared: mainly grazing by cattle and sheep on improved and native pastures
    Minor proportion uncleared: hardwood forestry (minor products); apiculture

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

LAND COMPONENT
Percentage of land system
Diagnostic features
1
40
Moderately steep slopes
2
30
Gentler slopes on broad ridge crests and spurs
3
5
Steeper rocky slopes and peaks
4
15
Drainage depressions deposits
5
10
Valley flats
PHYSIOGRAPHY
Slope %, typical and (range)
Slope shape
15 - 20, (10 - 40)
Convex or concave
8 - 12, (0 - 20)
Convex or concave
Variable, (20 - 50)
Straight
5, (0 - 10)
Concave
2, (0 - 3)
Straight or concave
SOIL
Parent material
Granite, granodiorite, diorite and gneiss
Colluvium
Alluvium
Description
Mainly black or brown sandy loam topsoil grading into reddish brown, brown or mottled yellowish brown blocky clay subsoil; some deep light yellowish brown uniform loamy sand on crests
Similar to components 1 and 2 but probably more uniform loamy sand, often stony; rock outcrop common
Black clay loam or clay grading into dark yellowish brown to grey mottled clay loam or clay
Little differentiated dark greyish brown sandy loam and mottled greyish brown sandy clay loam grading into clay at depth
Classification
Mainly Reel Podzolic Soils: some Brown or Yellow Podzolic Soils: some Brown Earths
Dr4.22, Dr2.21, Dr2.22, Db2.21, Dy3.21, Dy2.42, Gn2.11, Gn2.15, Gn3.14, Uc4.11
Wiesenboden, Black Earths
Um5.52, Ug5.1
Alluvial Soils. Wiesenboden
Uc1.21, Uc1.23, Uc5.21, Gn4.72
Surface texture
Sandy loam, but varying from loamy sand to sandy clay loam
Clay loam to clay
Sandy loam to sandy clay loam
Surface consistence
Hard when dry. friable to firm when moist
Firm to very firm when moist
Loose to slightly hard when dry
Depth (m)
Commonly 0.7 - 1.2
>2.0
>2.0
Nutrient status
Moderate
Moderate
Low to moderate
Available soil water capacity
Low to moderate
Moderate
Low to moderate
Perviousness to water
Slow to moderate
Slow
Moderate to rapid
Drainage
Mainly good
Poor to somewhat poor
Poor to good
Exposed stone (%)
Up to 10, mostly 0
0
0
Sampled profile number
45, 46
54
-
-
-
NATIVE VEGETATION
Structure of vegetation and characteristic species of dominant stratum
(+ Predominant species)
Grassy open forest II:
Mostly mixed forests with composition and predominant species variable — including E. albens (in east),
E. bridgesiana, E. dives, E. goniocalyx, E. globulus, E. globoidea (lower elevations), E. macrorhynch,a E. rubida, E. stellulata
Limited data — probably open forest I, II with species similar to components 1 and 2
Mainly grassy open forest II:
E. viminalis+, E. radiata
Occasionally woodland II:
E. goniocalyx
Grassy open forest II:
E. melliodora+ (higher better drained terraces):
E. ovata+ with or without
E. stellulata (lower poorer drained terraces)

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 determined
    Not determined
    Removal of trees
    Increased movement of water to groundwater; increased base-flow of streams
    Increased exposure of surface soil
    Increased overland flow and soil detachment



    Increased wind velocity over soil and increased detachment of soil
    Sheet and rill erosion






    Wind erosion
    1,2,4; moderate
    3; high






    3: low
    Uncommon







    Uncommon; locally severe on exposed slopes, especially at high elevations
    Clearing, logging, burning, overgrazing, road and dam building and other earth-moving activities, rabbit burrowing, trafficking by stock and vehicles.

    Clearing, logging, burning, overgrazing, road and dam building and other earth-moving activities, rabbit burrowing, trafficking by stock and vehicles.
    Increased flash flows and sediment load.






    -
    Increased physical pressure on soil
    Increased compaction

    With


    Reduced infiltration
    Structure decline



    Sheet and rill erosion
    1,2,5: low - moderate
    3; low
    4; moderate

    1,2,4; moderate
    3: high
    Uncommon, local occurrences



    Uncommon
    Increased trafficking overgrazing, export of organic matter


    As for sheet and rill erosion above
    -




    Increased flash flows
    Increased soil disruption
    Increased soil break-up


    Increased loss of topsoil cohesion
    Gully erosion


    Wind erosion
    1,2,4; moderate
    3,5; high

    3; low
    Uncommon; locally severe in components 4 and 5

    Uncommon; locally severe on exposed slopes, especially at high elevations
    As for wind, sheet and rill erosion above

    As for wind, sheet and rill erosion above
    Increased sediment load


    Increased sediment load
    Comments: -
Page top