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Collins (Cs)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Collins- gepArea: 67 sq. km (0.4%)

Hilly to undulating terrain on acidic, volcanic rocks, such as the Wellington Rhyolites and intercalated sedimentary rocks, is mapped in Collins land system. Such areas occur at low elevations close to the southern margin of the East Victorian Uplands and along some of the major river valleys. Most of the topography is of the ridge-and-ravine type with short, steep slopes but there are areas with lower relief, rounded ridges and gentler slopes. The valleys of some of the major streams, for example Freestone Creek, have small levees and alluvial terraces similar to those in Walnut land system.

Low to moderate rainfall acting on slow-weathering rocks such as rhyolites, rhyodacites and sandstones in a landscape with moderate and steep slopes, leads to a low rate of soil formation but a high rate of natural erosion. The soils therefore, tend to he stony, shallow and acidic and have little profile differentiation. Topsoils have a weak crumb structure while subsoils are usually apedal and earthy. In protected pockets the soils are often deeper and have clayey subsoils.

Open forest II dominates, with shrubby open forest III often on more protected slopes and in valleys. The open forests generally give way to woodlands on the rockier slopes.
A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Collins- image
Dry. mixed stringybark/box forest with a sparse sclerophyllous understorey and abundant leaf litter.

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

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

    Annual 8 - 12; lowest July (3 - 7), highest February (16 - 20)
    Temperature <10C (av.): May - September
    Rainfall < potential evapotranspiration: November – March
GEOLOGY
Age, lithology

    Devonian rhyolites (Wellington Rhyolites) and associated mudstones and sandstones; minor Snowy River rhyolites and rhyodacites and intercalated sedimentary rocks
PHYSIOGRAPHY
Landscape
Elevation range (m)
Relative relief (m)
Drainage pattern
Drainage density (km/km2)

    Hilly to undulating terrain

    80 - 700
    80 - 210
    Dendritic
    1.3
PRESENT LAND USE
    Mostly uncleared: hardwood forestry (minor products); apiculture; bush grazing of cattle (limited)
    Minor portion cleared: grazing of cattle

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

LAND COMPONENT
Percentage of land system
Diagnostic features
1
65
Slopes with dry forest
2
20
Protected slopes with slightly
moister forest than component I
3
10
Rocky slopes with sharp crests
and shallower soils
4
5
Terraces in major
drainage corridors
PHYSIOGRAPHY
Slope %, typical and (range)
Slope shape
10 - 15, (0 - 30)
Variable
15 - 25, (10 - 40)
Concave
25 - 35, (20 - 60)
Straight
2, (0 - 5)
Straight
SOIL
Parent material
Rhyolite; some mudstone and sandstone; minor rhyodacite
Stony alluvium
Description
Very dark greyish brown to black loamy sand to sandy clay loam grading into brown or yellowish brown sandy loam to clay loam, or occasionally clay. Generally very stony with rock outcrop in component 3
Limited observations — undifferentiated brown sand locally underlain by gravel; stone and gravel in stream channels
Classification
Lithosols. Brown Earths and intergrades: some Yellow Earths. Yellow Podzolic Soils
Uc4.11, Uc4.31, Uc5.21, Um6.12. Gn2.81 Gn2.84. Dy3.41
Alluvial Soils
Uc1.23
Surface texture
Loamy sand to sandy clay loam
Sand
Surface consistence
Variable; soft to hard when dry, friable to firm when moist
Loose when dry or moist
Depth (m)
Mostly0.6 - 1.1, can be less: 0 in areas of rock outcrop
>2.0
Nutrient status
Low to moderate
Very low
Available soil water capacity
Low to moderate
Very low
Perviousness to water
Moderate
Rapid
Drainage
Good
Somewhat excessive
Exposed stone (%)
Very variable; <60
0
NATIVE VEGETATION
Structure of vegetation and characteristic species of dominant stratum
(+ Predominant species)
Open forest II:
Generally mixed forests with variable composition — including
E. consideniana, E. macrorhyncha,
E. polyanthemos (one of which
usually predominant),
E. globoidea, E. muellerana,
E. goniocalyx.
Shrubby open forest II, III:
Mixed forests with variable composition — including
E. cypellocarpa+,
E. globoidea+, E. muellerana+,
E. polyanthemos+, E. macrorhyncha+
Shrubby woodland II:
Mixed woodlands with variable composition — including
E. dives +, E. macrorhyncha+,
E. polyanthemos, E. consideniana
Mainly shrubby open forest III, IV:
E. viminalis+ with or without
E. cypellocarpa+

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
    Sheet and rill erosion
    1,2,3: high
    Not determined
    Clearing, logging, overgrazing, 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
    1,2,3,4: low



    1,2,3; high
    Not determined



    Not determined
    Loss of organic matter in topsoil


    As for sheet and rill
    erosion above
    -



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


    Streambank erosion
    1,2: moderate
    3; low

    4; high
    Not determined


    Not determined
    As for sheet and rill erosion above

    As for sheet and rill
    erosion above
    Increased sediment loam


    Increased sediment load and turbidity of stream.
    Comments: No observations of deterioration
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