Gormandale (Gd)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Gormandale- geo

Area: 296 sq. km (1.5%)

This land system is confined to the northern slopes of the Baragwanath Anticline, along the steeper land near the Rosedale Monocline. The hills and slopes mostly occur on very sandy and often lateritised Tertiary materials but localized variation in texture is not uncommon. Although the sands are suitably sized for aeolian transport most of the land forms have formed through erosion by water.

Springs and seepage areas occur in the lower tracts of fluvial corridors, the larger of which are mapped in Sandy land system.

Under the high rainfall, acidic soils, usually with black and dark brown, cemented layers (coffee-rock) at depth, have developed where the depth of sand is greater than 0.5 m. Sometimes the brown, sandy, subsoil layer is not cemented. Where clay underlies the sand cover at less than about 0.5 m depth, it is common to find acidic duplex soils with yellow, mottled clay subsoils. The soils are droughty and infertile.

The vegetation in uncleared areas is mostly ferny or heathy woodland I and II with shrubby woodland I and II in alluviated valley floors. Similar vegetation probably once covered the cleared land.

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Gormandale- image

Deep, white sands with coffee rock, now being used for pine growing, are common in Gormandale land system.

CLIMATE Rainfall, mean (mm) Temperature, mean (°C) Seasonal growth limitations	Annual 700 - 1200; lowest January (30 - 60), highest October (60 - 90) Annual 12 - 14; lowest July (8 - 10), highest February (19 - 21) Temperature <10°C (av.): May - September Rainfall < potential evapotranspiration: November – March
GEOLOGY Age, lithology	Mainly Tertiary sands, often lateritic
PHYSIOGRAPHY Landscape Elevation range (m) Relative relief (m) Drainage pattern Drainage density (km/km²)	Hills and slopes on the northern flanks of the Baragwanath Anticline 20 - 320 20 - 60 Dendritic 0.4
PRESENT LAND USE	Approximately half the area uncleared: some areas in Holey Plains State Park; apiculture (limited) Cleared portion: softwood forestry; grazing of beef cattle and sheep on both native and improved pastures

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Gormandale- cs

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

LAND COMPONENT Percentage of land system Diagnostic features	1 85 Crests, slopes and low hills	2 15 Valley flats
PHYSIOGRAPHY Slope %, typical and (range) Slope shape	5 - 10, (0 - 15) Variable, predominantly concave or convex	3, (0 - 5) Straight
SOIL
Parent material	Windblown and colluvial sand over highly variable substrata, usually older weathered clay, gravel or lateritic material	Colluvium and alluvium
Description	Mostly deep sand with whitish subsurface and brown or black and brown hardpan (coffee rock) or nodular concretions at depth; lighter coloured sand below. Occasionally shallow dark and grey sand overlies yellow mottled acidic clay subsoil	Limited observations — probably deep sand with black and brown hardpan including coffee rock; deep undifferentiated sand
Classification	Podzols, some Yellow Podzolic Soils Uc2.31 and Uc2.36 common; also Uc2.21, Uc2.32, Uc2.34, Uc4.32, Dy5.21	Podzols, Alluvial Soils Uc2.36, Uc1.2
Surface texture	Sand	-
Surface consistence	Soft	-
Depth (m)	>2.0	>2.0
Nutrient status	Low	Low
Available soil water capacity	Low	-
Perviousness to water	Rapid	-
Drainage	Mostly somewhat excessive	Poor to somewhat poor
Exposed stone (%)	0	0
Sampled profile number	70, see also Nicholson (1978) Profile 758	-
NATIVE VEGETATION Structure of vegetation and characteristic species of dominant stratum (+ Predominant species)	Ferny or heathy woodland I, II: Species composition and predominance variable — frequently one or more of E. consideniana, E. nitida and E. viminalis var. racemosa, often with Banksia serrata, E. dives, E. cephalocarpa, E. globoidea and E. muellerana occur less commonly	Limited data — similar to Sandy land system, component 3

Disturbance	Affected process and trend	Primary resultant deterioration			Casual activities	Primary off-site process
Disturbance	Affected process and trend	Form	Susceptibility of components	Incidence with components	Casual activities	Primary off-site process
Alteration of vegetation: — reduction in leaf area, rooting depth and/or perenniality	Reduced transpiration, resulting in increased deep percolation and leaching	Nutrient loss	1; high	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 sand	Sheet and rill erosion Wind erosion	1; moderate – high 1; moderate - high	Uncommon: severe in localised areas Uncommon: limited to cleared areas	Clearing, softwood logging, road and dam building and other earth-moving activities, rabbit burrowing, trafficking by stock and vehicles. As for sheet and rill erosion above	Increased run-on and sedimentation in lower areas Encroachment by sand
Increased physical pressure on soil	Increased compaction With Reduced infiltration	Structure decline Sheet and rill erosion	1,2; low 1; moderate - high	Uncommon Uncommon: severe in localised areas	Increased trafficking export of organic matter As for sheet and rill erosion above	- Increased flash flows
Increased soil disruption	Increased soil break-up Increased loosening of sand	Gully erosion Wind erosion	1; high 2; moderate 1; moderate - high	Uncommon: severe local occurrences Uncommon: limited to cleared areas	As for sheet and rill erosion above As for sheet and rill erosion above	Increased sediment load in streams and sedimentation in lower areas Encroachment by sand
Comments: A single season's rainfall can cause quite severe gullying in unprotected roadside drains or in wheel ruts along tracks

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