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Turton (Tn)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Turton- geoArea: 922 sq. km (4.5%)

Turton land system occurs on the Carboniferous sediments that outcrop in the central-west of the East Victorian Uplands. The terrain is mountainous with a prominant ridge-and-ravine topography, long, steep slopes and active soil creep. Relief is high and rock outcrop abundant. There is evidence of some structural control of slope shape by the outcrop of the harder quartzose members of the sediments.

Red-bed shales also outcrop and can contribute to slope failure. The valleys of the major rivers, notably the Avon, Macalister, Mitchell and Moroka Rivers have levees and alluvial terraces similar to, though smaller than, those mapped as Walnut land system. Turton is similar in geology and topography to Macalister land system but it occurs at lower elevations and is much drier.
A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Turton- image
Steep, forested slopes with rock outcrop along the Licola Road
The more resistant sandstones and the more weatherable red-bed shales form two contrasting soil parent materials. However, the sandstones predominate and these, together with natural erosion on steep slopes, have produced shallow, stony soils. Rainfall is moderate and the soils are well-leached and acidic. Low clay content and erosion suppress profile development. Topsoils tend to have crumb structure but subsoils are usually earthy and apedal.

Moisture availability is generally low but it tends to be greater on protected slopes at higher elevations. This is reflected in the vegetation which is mostly dry, shrubby open forest II grading into more vigorous, humid forests with species characteristic of moister conditions at higher elevations.

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

    Annual 800 - 1400; 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
GEOLOGY
Age, lithology

    Carboniferous quartzose sandstones and red-bed shales (Snowy Plains Formation)
PHYSIOGRAPHY
Landscape
Elevation range (m)
Relative relief (m)
Drainage pattern
Drainage density (km/km2)

    Steep mountains with ridge-and-ravine topography

    100 - 1340
    180 - 660
    Dendritic
    0.9
PRESENT LAND USE
    Mostly uncleared: hardwood forestry (minor timber products); bush grazing of cattle (limited); apiculture; small area in Glenaladale National Park
    Minor proportion cleared: grazing of beef cattle and sheep

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

LAND COMPONENT
Percentage of land system
Diagnostic features
1
80
Slopes with minor structural ledges and dry
forests
2
15
Slopes with more vigorous and/or more humid
forests
3
5
Discontinuous narrow terraces on
major drainage depressions
PHYSIOGRAPHY
Slope %, typical and (range)
Slope shape
35 - 45, (10 - 100)
Straight
35 - 45, (10 - 100)
Straight
Variable; (0 - 30)
Straight to concave but uneven
SOIL
Parent material
Sandstone and shale; minor colluvium
Stony alluvium
Description
Generally very shallow often stony. Dark greyish brown sandy loam to loam topsoil merging
into greyish brown or reddish brown sandy loam or sandy clay loam subsoil; some yellowish
brown clay subsoil. Probably more organic matter in soils of component 2
No observations — probably light to medium
textured, often stony soils
Classification
Lithosols, some Red Earths and Yellow Podzolic Soils in pockets of deeper, stable soil
Uc1.44, Uc4.11, Uc4.13, Urn 1.43, Urn 1.44, Um4.21, Um5.52, also Dy2.21, Dy3.21
-
Surface texture
Sandy loam to loam
-
Surface consistence
Slightly hard when dry, friable when moist
-
Depth (m)
<0.6, but deeper pockets
-
Nutrient status
Low
>2.0
Available soil water capacity
Low
Low
Perviousness to water
Moderate
Variable
Drainage
Good
Moderate to rapid
Exposed stone (%)
Variable; 0 - 40
Variable
Sampled profile number
-
-
NATIVE VEGETATION
Structure of vegetation and
characteristic species of
dominant stratum
(+ Predominant species)
Shrubby open forest II:
Higher elevations — no site data but probably E. dives+, E. rubida+
Lower elevations — generally mixed stands, species including E. consideniana, E. dives, E. goniocalyx, E. macrorhyncha, E. mannifera, E. polyanthemos E. sideroxylon, E. sieberi
Open forest II, often shrubby:
Limited information — probably E. rubida+ and possibly E. delegatensis+ in the wetter areas grading into E. cypellocarpa+ and E. obliqua+; E. globoidea and E. macrorhyncha sometimes in drier sites
Occasionally closed forest II of Acmena smithii, climbers, ferns and epiphytes in minor drainage lines
Mainly open forest II, III often shrubby:
E. viminalis and/or E. radiata either of which may be predominant; occasionally E. melliodora+
Rarely closed forest II:
Acmena smithii, vines, ferns and epiphytes

    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

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


    a) increased deep
    percolation



    b) increased regolith
    wetness




    Decreased root-binding




    Nutrient loss




    Landslip and soil creep




    Landslip and soil creep




    Not determined




    1; moderate
    2; moderate – high



    1; moderate
    2; moderate - high




    Not determined




    Uncommon: limited occurrence of old landslips near Licola


    Uncommon: limited
    occurrence of old
    landslips near Licola




    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 soil
    Increased overland flow and soil detachment
    Sheet and rill erosion
    1,2; moderate - high
    Common
    Clearing, logging, burning, overgrazing, road building and other earth-moving activities, trafficking by stock.
    Increased flash flows and sediment load.
    Increased physical pressure on soil
    Increased compaction

    With

    Reduced infiltration
    Structure decline



    Sheet and rill erosion
    1; low
    2; low - moderate
    3; moderate

    1,2; moderate - high
    Not determined



    Common
    Increased trafficking, overgrazing, export of organic matter

    As for sheet and rill erosion above
    -



    Increased flash flows
    Increased soil disruption
    Increased soil break-up
    Gully erosion


    Streambank erosion
    1,2; moderate – high


    3; high
    Uncommon: local occurrence

    Uncommon
    As for sheet and rill erosion above

    As for sheet and rill erosion above
    Increased sediment load


    Increased sediment load
    Comments: Prolonged rainfall events after clearing of native vegetation on steep slopes will increase the risk of landslips/soil creep occurring
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