Cascade (Cc)

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

Area: 71 sq. km (0.4%)

Cascade land system occurs below the subalpine tract. mostly flanking the Baw Baw Plateau, and is traversed by many drainage lines. Although the gradient is moderate, the terrain is hilly with short, steep slopes, rocky crests, and some bogs. Dissection is based upon jointing pattern in the granodiorite, with major streams incised in joints normal to the contour.

A cool climate, high rainfall and a parent rock that weathers easily have produced deep soils, even on steep slopes. Weathering of iron-hearing minerals, combined with leaching of bases and a high production of organic matter by the vegetation, have resulted in moderately acidic, well-aggregated soils, with a crumb or fine blocky structure in the upper horizons and more earthy fabric in the subsoil.

The vegetation is mainly shrubby open forest III, with some closed forest II and III in narrow drainage floors and open forest II on rocky crests.

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - </font>land system Cascade - image

Eucalyptus regnans (mountain ash) forest with an understorey of tree ferns characteristic of slopes at lower elevations.

CLIMATE Rainfall, mean (mm) Temperature, mean (°C) Seasonal growth limitations	Annual L200 - 1800: lowest January or February (70 - 100), highest August or September (130 - L80) Annual 8 - I2; lowest July (3 - 7), highest February (16 - 20) Temperature <10°C (av.): April - October Rainfall < potential evapotranspiration: February; frequent winter snow
GEOLOGY Age, lithology	Devonian; Baw Baw Granodiorite
PHYSIOGRAPHY Landscape Elevation range (m) Relative relief (m) Drainage pattern Drainage density (km/km²)	Moderately sloping flanks below the Baw Baw Plateau 560 - 1320 180 - 360 Rectangular 1.3
PRESENT LAND USE	Uncleared: hardwood forestry (ash and general construction timber); apiculture; small areas included in Baw Baw National Park

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

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

LAND COMPONENT Percentage of land system Diagnostic features	1 75 Slopes, mostly short and steep	2 10 Crests often rocky	15 Narrow drainage depressions. often with small peat bogs
PHYSIOGRAPHY Slope %, typical and (range) Slope shape	25 - 30, (20 - 50) Straight to convex	<5, (0 - 10) Convex	<1. (0 - 5) Concave
SOIL
Parent material	Granodiorite		Alluvium and colluvium
Description	Black sandy loam to sandy clay loam, merging into brown similarly textured or more clayey subsoil with weak structure; generally shallower in component 2		Shallow sandy and gravelly undifferentiated soils; localised organic soils
Classification	Brown Earths Uc6.11, Uc6.14, Gn2.11, Gn2.41	Brown Earths Um7.11	Alluvial Soils, Acid Peat Uc1. - .0
Surface texture	Sandy loam to sandy clay	Sandy loam to sandy clay	Variable
Surface consistence	Soft	Soft	Soft
Depth (m)	>2.0	>2.0	>2.0
Nutrient status	Moderate	Moderate	Moderate; low for peats
Available soil water capacity	Moderate	Moderate	Moderate
Perviousness to water	Rapid	Rapid	Rapid
Drainage	Good	Good	Somewhat poor; very poor for peats
Exposed stone (%)	0 - 5	0 - 5	0
Sampled profile number	-	-	-
NATIVE VEGETATION Structure of vegetation and characteristic species of dominant stratum (Predominant species)	Shrubby open forest Ill: Higher elevations — E. delegatensis+ with or without E. nitens; E. nitens+ Lower elevations — E. regnans+ with or without E. obliqua Closed forest II, III of Nothofagus cunninghamii sometimes on lower slopes	Limited data — probably mainly open forest II: E. delegatensis	Bogs principally with Richea continentis, Carex appressa and Sphagnum spp. Scattered N. cunninghamii and Leptospermum grandifolium on higher ground

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; moderate 2; low	Not determined	Clearing, logging, burning, 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; moderate 3; high 1; moderate 2; low	Not determined Not determined	Loss of organic matter from topsoil. As for sheet and rill erosion above	- Increased flash flows
Increased soil disruption	Increased soil break-up	Gully erosion	1,2; low - moderate	Not determined	As for sheet and rill erosion above	Increased sediment load.
Comments: No observations of deterioration

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