Collins (Cs)

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

Area: 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 <10°C (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- cs

A 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
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	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

Page top