Briagolong (Bg)

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

Area: 119 sq. km (0.6%)

Prior-stream courses are clearly evident across parts of the later Pleistocene terrace; most of these are included in the Briagolong land system. Partially infilled stream channels occur together with characteristic old levees of reddish alluvium. This reddish alluvium is extensive in the upstream parts of the former stream courses. Near Cowwarr and Briagolong. the old stream deposits resemble outwash fans. Further downstream a clay plain becomes more common and ultimately dominates, to become the Sale land system. Local run-off water still ponds in some of the old stream channels.

Most of the surface alluvial deposits are clays and silts. The frequency of reddish colours in these materials is probably due to high permeability and to redness of the parent materials. In most of the land system, duplex and gradational soils have formed. Leaching has not been very intense and the subsoils tend to be neutral to slightly alkaline at depth, possibly due to the presence of calcium carbonate or sodium ions. Where drainage is poorer the soils are often strongly mottled.

The native vegetation. now almost entirely removed. appears to have been mainly grassy open forest II dominated by E. tereticornis.

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

A Briagolong relict channel with Eucalyptus tereticornis (forest red gum) growing on the Hatter land above it.

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 (8 - 10). highest February (19 - 21) Temperature <10°C (av.): June - August Rainfall < potential evapotranspiration: November – March
GEOLOGY Age, lithology	Upper Pleistocene alluvial deposits of gravels, sands, minor silts and clays
PHYSIOGRAPHY Landscape Elevation range (m) Relative relief (m) Drainage pattern Drainage density (km/km²)	Relict levees and outwash fans 20 - 60 0 - 10 Dendritic 1.4
PRESENT LAND USE	Cleared: grazing of beef and dairy cattle on improved and often irrigated pastures: cropping (limited): apiculture (limited)

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

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

LAND COMPONENT Percentage of land system Diagnostic features	1 30 Dissected fans with red soils	2 20 Levees and levee slopes with loamy to clayey soils	3 20 Levees and levee slopes with sandy soils	4 15 Plains (too small to map as Sale land system)	5 15 Channels, swales, oxbows, often partially filled
PHYSIOGRAPHY Slope %, typical and (range) Slope shape	<5. (0 - 15) Convex	2. (0 - 5) Convex, concave	2. (0 - 5) Convex, concave	2, (0 - 3) Straight	1, (0 - 5) Concave
SOIL
Parent material	Silt, clay, sand and gravel
Description	Dark brown sandy loam to clay loam topsoil abruptly overlying blocky red or reddish brown clay subsoil	Limited observations — probably as for component 1, but often with lighter textured subsoil	No observations — probably uniform and gradational soils with sandy textures	Limited observations — mottled yellow and brown gradational, duplex and uniform soils	No observations — probably mottled greyish brown fine textured soils
Classification	Red-brown Earths and intergrades with Solodic Soils Dr2.22. Dr3.21. Dr3.22	Red-brown Earths, Red Earths Dr3.22. Um5.52	-	Wiesenboden, Yellow Earths. Yellow Podzolic Soils and Solodic Soils Gn3.73. Um5.52	Humic Gleys
Surface texture	Sandy loam to clay loam		-		Probably clay loam to clay
Surface consistence	Soft to hard when dry		-		Firm when moist
Depth (m)	>2.0		>2.0	Probably similar to Sale land system, component 1	>2.0
Nutrient status	Moderate		Low to moderate (?)		Moderate
Available soil water capacity	Moderate		Low to moderate (?)		Moderate
Perviousness to water	Slow	Slow to moderate	Moderate to rapid		Slow
Drainage	Moderately good to good	Moderately good to good	Good		Very poor to poor
Exposed stone (%)	0	0	0	0	0
Sampled profile number	57.58	-	-	-	-
NATIVE VEGETATION Structure of vegetation and characteristic species of dominant stratum (+ Predominant species)	Grassy open forest II: E. tereticornis+ Clearing has made it difficult to determine if any other predominant or associated species

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	Not determined	Not determined	Removal of trees	Increased movement of water to groundwater.
Increased exposure of surface soil	Increased overland flow and soil detachment	Sheet and rill erosion	1; low 2,3; moderate	Uncommon; local occurrence	Clearing, cultivation, burning, overgrazing, 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; low – moderate l: low 2.3: moderate	Not determined Uncommon: local occurrence	Increased trafficking and cultivation, overgrazing, export of organic matter As for sheet and rill erosion above	- Increased flash flows
Increased soil disruption	Increased soil break-up	Gully erosion	12,3,4: low 5; moderate	Uncommon; local occurrence	As for sheet and rill erosion above	Increased sediment load.
Comments: -

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