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

Victorian Resources Online

Stewart (Sw)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Stewart- geoArea: 41 sq. km (0.2%)

Extremely silty areas of Tertiary and adjoining Devonian sediments have been mapped in Stewart land system. These areas have rounded hills with moderate slopes and some undulating terrain. Broad alluvial floors in concave valleys are fed by seepage from the hills and carry water all year. These floors are characteristically swampy, with peaty surface materials. A diagnostic feature of this land system is the heathy nature of the vegetation which occurs on most of the slopes despite the relatively high rainfall. The silty and clayey parent materials and the moderate to gentle slopes have promoted the development of duplex and gradational soils. These have been strongly leached and are strongly to moderately acidic. The very high silt contents often result in poor internal drainage and this, along with the common, extremely low nutrient contents, leads to the heathy vegetation. Land with moderate slopes and slowly pervious soils is likely to cause a higher proportion of surface run-off, increasing the erosion risk. The badly-eroding road batters indicate that the soils are highly susceptible to erosion.

The vegetation is often a heathy open woodland I or heathy woodland I, though open forest II occurs on better sites. Well-drained alluvial terraces support open forest II or III, often layered or shrubby while swampy drainage areas have a closed scrub or shrubby woodland I.
A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Stewart- image
Closed scrub of
Melaleuca squarrosa (scented paper-bark) and Gleichenia microphylla (scrambling coral fern) growing in a seepage area

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

    Annual 700 - 1200; lowest January or February (40 - 70), highest August or October (90 - 120)

    Annual 12 - 14; lowest July (8 - 10), highest February (19 - 21)
    Temperature <10C (av.): May - September
    Rainfall < potential evapotranspiration: November – March
GEOLOGY
Age, lithology
PHYSIOGRAPHY
Landscape
Elevation range (m)
Relative relief (m)
Drainage pattern
Drainage density (km/km2)

    Rounded hills and undulating terrain with broad swampy valley floors

    100 - 280
    60 - 120
    Dendritic
    1.8
PRESENT LAND USE
    Mostly uncleared: hardwood forestry (minor timber products); apiculture
    Minor proportion cleared: grazing of beef and dairy cattle on improved pastures

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Stewart- csA study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Anderson1 - graph

LAND COMPONENT
Percentage of land system
Diagnostic features
1
45
Slopes with very silty soils and
heathy woodlands
2
35
Slopes with silty soils and
forests
3
15
Swampy drainage depressions
4
5
Well drained terraces
PHYSIOGRAPHY
Slope %, typical and (range)
Slope shape
15 - 20, (5 - 30)
Convex and concave
15 - 20, (5 - 30)
Convex and concave
<1, (0 - 2)
Straight
<2, (0 - 5)
Straight but uneven
SOIL
Parent material
Silt and clay; minor sandstone, siltstone and mudstone
Alluvium and plant debris
Alluvium
Description
Dark greyish brown sand to silty loam topsoil, abrupt or gradual change to mottled, yellowish brown or yellow, generally blocky structured clay (sometimes sandy clay loam) subsoil
Black organic loam over variable
mottled grey mineral layer;
shallow peat in places
Single observation — probably
undifferentiated brown stratified
soils, often mottled at depth
Classification
Yellow Podzolic Soils, Yellow Earths
Dy3.41, Dy5.21, Gn4.81
Humic Gleys, Acid Peats
Uc1.41, O
Alluvial Soils/Yellow Earths
Um2.3-
Surface texture
Sand to silty loam
Loam
-
Surface consistence
Soft to hard when dry
Friable to firm when moist
-
Depth (m)
>1.0
>2.0
>2.0
Nutrient status
Extremely low
Low to moderate
Low to moderate
Low to moderate
Available soil water capacity
Low to moderate
Low to moderate
Moderate to high
Variable
Perviousness to water
Slow
Slow
Variable
Variable
Drainage
Poor to somewhat poor
Somewhat poor to moderately good
Very poor to poor
Somewhat poor, in places good
Exposed stone (%)
0
0
0
0
Sampled profile number
53
-
-
-
NATIVE VEGETATION
Structure of vegetation and
characteristic species of
dominant stratum
(+ Predominant species)
Heathy open woodland I, heathy
woodland I:
E. consideniana+ and/or E. cephalocarpa+
Open forest II:
E. consideniana+; E. obliqua+, E. radiata+ in areas of better drainage
Closed scrub:
Melaleuca squarrosa
Shrubby woodland I:
E. ovata+, E. radiata, with an understorey of Melaleuca squarrosa and/or Leptospermum spp.
Limited data — probably shrubby
or layered open forest II, III:
E. obliqua+ with E. viminalis and E. radiata observed; E. ovata presumed

    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; moderate - high
    Uncommon
    Clearing, logging, burning, overgrazing, road 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
    1,2,4; moderate
    3; high


    1,2; moderate - high
    Uncommon



    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
    Gully erosion

    Streambank erosion
    1,2; high

    4; moderate
    Uncommon

    Uncommon
    As for sheet and rill erosion above

    As for sheet and rill erosion above
    Increased sediment load


    Increased sediment load
    Comments: Road batters are prone to collapse and erode, probably aided by perched water tables and lateral seepage. Some minor salting may occur to the east of Newry.
Page top