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Morass (Ms)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Morass- geoArea: 216 sq. km (1.1%)

All small water bodies and major swamps on the lowlands are included in Morass land system where mapping scale permits.

The great inherent variability is difficult to express in terms of land components which must cater for swampy areas in fluviatile, aeolian, lacustrine, littoral and paludal situations. The swamps may be permanent or ephemeral, with fresh or brackish water.

Soil parent materials probably range from sand to clay. All areas are poorly drained and some may be permanently inundated. Soil development in the permanently inundated areas is almost negligible. Elsewhere the formation of organic-rich mineral horizons at the surface has usually occurred. The frequent sedimentation generally preventing the development of peats. Subsoils have undergone little alteration beyond the development of grey and olive yellow colours, and mottling. In areas with saline water, the reaction generally is alkaline but in other places the soils are often highly acidic. The erosion hazard is usually negligible except along shorelines and river banks which may be threatened by wave erosion or undercutting by flowing water.

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Morass- image
A swampy plain with a sedgeland community adjoining a large lagoon, typical of Morass land system.
Vegetation varies with degree of inundation and salinity. Swamps typically have a zonation of vegetation with herbfields and sedgelands in the centre, grading into closed scrub bordered by open forest I or II. Lagoon margins also usually have open sedgelands, closed scrub and open forests. Tall grassland of Phragmites communis sometimes occurs as well.

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

    Annual 500 - 800: lowest July (30 - 50), highest October (50 - 80)

    Annual 12 - 14; lowest July (9 - 10). highest February (19 - 20)
    Temperature <10C (av.): No months
    Rainfall < potential evapotranspiration: November – March
GEOLOGY
Age, lithology

    Holocene fluviatile, aeolian, lacustrine and littoral deposits of sands, silts and clays, now in paludal environments
PHYSIOGRAPHY
Landscape
Elevation range (m)
Relative relief (m)
Drainage pattern
Drainage density (km/km2)

    Swampy plains and water bodies

    0 - 100
    0 - 20
    Undeveloped
    0.2
PRESENT LAND USE
    Mostly uncleared: mainly in Lake Coleman, Dowd Morass, The Heart Morass. Clydebank Morass, McLeod Morass, Blond Bay and Jones Bay State Game Reserves, Sale Common State Game Refuge, The Lakes National Park and Gippsland Lakes Coastal Park: grazing on private land (limited)

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

    LAND COMPONENT
    Percentage of land system
    Diagnostic features
1
40
Freshwater swampy plains, sandy soils
2
20
Brackish swampy plains, sandy soils
3
20
4
20
Lagoons and marginal reed-swamps
    PHYSIOGRAPHY
    Slope %,typical and (range)
    Slope shape
<1, (0-2)
Straight or slightly concave
<1, (0-2)
Straight or slightly concave
<1, (0-2)
Straight or slightly concave
0, (-)
Concave
    SOIL
    Parent material
Sand, silt and clay of fluviatile, aeolian, lacustrine and littoral origin
    Description
Limited observations – black organic sandy loam topsoil grading into grey, olive yellow and brownish yellow mottled sandy subsoil; often more clayey substrata within a depth of 2 m
Dark sandy loam to silty clay loam topsoil, sometimes peaty subsoil; subsoil often stratified and including peat
No observations – thin brown topsoil of variable texture over grey stratified and variably textured sediments; no soils in permanently inundated areas
    Classification
Humic Gleys
Uc1.22, Uc1.44
Humic Gleys, some Acid Peats
Variable; Um1.21, Um1.43; O
-
    Surface texture
Sandy loam
Sandy loam to silty clay loam
Variable texture
    Surface consistence
Friable when moist
Plastic when wet
-
    Depth (m)
>2.0
>2.0
>2.0
    Nutrient status
Low to moderate
Moderate
Moderate
    Available soil water capacity
Moderate to high
Moderate to high
Not applicable
    Perviousness to water
Rapid
Slow to moderate
Slow
    Drainage
Very poor to poor
Very poor to poor
Very poor to permanently waterlogged
    Exposed stone (%)
0
0
0
    Sampled profile number
-
-
-
    NATIVE VEGETATION
    Structure of vegetation and characteristic species of dominant stratum
    (+ Predominant species)
Zonation of vegetation with, from centre of swamps to drier ground.
The lagoon margins have open sedgelands of hydrophytes, closed scrub of Melaleuca spp., or, on drier fringes, open forest of E. ovata.

Reed-swaps with tall grassland of phragmites communis
Closed sedgeland: Cyperaceae (often Eleocharis sphacelata), Juncaceae
Closed scrub: Melaleuca ericifolia or
M. squarrosa
Open forest I or II: E. ovata,
E. tereticornis (drier areas)
Mainly herbfield: Salicornia spp.
Sedgeland: Juncus maritimus or Ghania spp.
Closed scrub: M. ericifolia
Structure and species as for component 1

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 raised groundwater table
    Waterlogging
    1,2.3: low
    Common
    Reduced plant-water use
    in the catchment
    Raised groundwater
    table
    Increased exposure of surface soil
    Increased soil detachment
    Wave erosion
    4: low
    Uncommon
    Loss or damage of
    marginal reed
    community
    Increased lake turbidity
    Increased physical pressure on soil
    Increased compaction

    With

    Reduced infiltration
    Structure decline



    Ponding of water
    12: low
    3; moderate


    3: moderate
    Uncommon



    Common
    Increased trafficking and cultivation, overgrazing, export of organic matter

    Increased trafficking and cultivation, overgrazing, export of organic matter
    -



    -
    Increased soil disruption
    Increased soil break-up
    Wave erosion
    4: low
    Uncommon
    As for wave erosion above
    Increased lake turbidity
    Comments: Wave erosion along the shores of the lagoons is conceivable as a result of damage to the reed swamps, but the shallowness of the lagoons probably limits the force of the waves
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