Soil/Landform Unit - Merryvale lakes and ridges

WLRA Landform Merryvale lakes and ridges

Looking west towards lakes within the swales between former beach ridges

Area: 1409 ha

0.06% of CMA region

This unit of low-lying terrain consists of a single depression (lake and

) complex about 25 km north-east of Edenhope. This plain, depression and associated rise (lunette) are part of North West Dunefields and Plains; more specifically they are part of the low ridge tops with remnant sands and orientated depressions (5.5.2). This low-lying plain occurs between NNW/SSE low sandy ridges. Plains, flats, drainage depression and a lunette occur as landscape components. Receiving drainage from the surrounding rises (low ridges), soils include yellow, brown and grey

sodic

texture contrast soils, with grey and brown cracking clay soils (

Vertosols

) in the depression. These clays occur on the dune as well as occasional red sodic texture contrast soils (

Sodosols

) associated with the crests. Sheet and wind erosion susceptibility is associated with the lighter topsoils of exposed crests.

Compaction

is also a potential land degradation susceptibility, as is waterlogging in the depression and to some extent the plain, where topsoil is shallow. Remnant vegetation is composed of vegetation communities such as Damp Sands Herb-rich Woodland, Red Gum Wetland, Brackish Lake Mosaic, Lunette Woodland and Plains Woodland.

Overgrown dried lake bed amid plains near Karnak
	Gently undualting sandy rises near Karnak

Component	1	2	3
Proportion of soil-landform unit	70%	10%	20%
CLIMATE Rainfall (mm)	Annual: 540
CLIMATE Rainfall (mm)	Annual: 540
Temperature (^oC)	Minimum 8, Maximum 21
Precipitation less than potential evapotranspiration	October–April
GEOLOGY Age and lithology	Neogene marine sand and silt (Parilla Sand); Quaternary paludal silt and clay; Quaternary aeolian dune sand (Lowan Sand)
GEOLOGY Age and lithology
Geomorphology	5.5.2 Low ridges and oriented swales of the North West Dunefields and Plains
LANDUSE	Uncleared areas: nature conservation Cleared areas: dryland cropping; sheep grazing
LANDUSE
TOPOGRAPHY Landscape	Lakes and lunette complex
TOPOGRAPHY Landscape	Lakes and lunette complex
Elevation range (m)	151–165
Local relief (m)	1
Drainage pattern	Dendritic
Drainage density (km/km²)	0.7
Landform	Playa plains
Landform element	Plain	Lunette	Closed depression
Slope and range (%)	1 (1-3)	5 (1-10)	0 (0-1)
Slope shape	Straight	Convex	Concave
NATIVE VEGETATION Ecological Vegetation Class	Plains Woodland (50.0%), Brackish Lake Mosaic (25.4%), Red Gum Wetland (16.4%), Other (8.2%)
NATIVE VEGETATION Ecological Vegetation Class
SOIL Parent material	Marine sand and silt	Aeolian sand	Paludal silt and clay
SOIL Parent material	Marine sand and silt	Aeolian sand	Paludal silt and clay
Description (Corangamite Soil Group)	Sodic brown, yellow and grey texture contrast soils (38)	Grey and brown cracking clay soils (37) and sodic red texture contrast soils (39)	Grey and brown cracking clay soils (37)
Soil type sites	LSWW11, LSWW17, LSWW13	NA174, LS3, LSWW9	LS3, LSWW9, LSWW5
Surface texture	Loamy sand	Light clay	Medium clay
Permeability	Moderate	Moderate - slow	Slow
Depth (m)	1.3	> 2	> 2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS Critical land features, processes, forms	Susceptible to wind and sheet erosion where surfaces with little organic matter are exposed. Susceptible to compaction where hardsetting and restricted drainage. Upper soil is susceptible to acidification.	Susceptible to sheet and rill erosion along with wind erosion when exposed. Dispersive and deep subsoils susceptible to gully erosion on steeper slopes. Compaction of upper soil variable depending on soil depth and moisture content.	Susceptible to seasonal inundation and waterlogging. Surface soils friable and only slightly susceptible to wind erosion. Soils susceptible to compaction at critical moisture contents.

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