Soil/Landform Unit - Mosquito Creek swamp sand plains

WLRA Landform Mosquito Creek swampy sand plains

Centre pivot irrigator on swampy sand plain near Langkoop used for dairy production

Area: 10 433 ha

0.45% of CMA region

As a valley complex associated with a northern tributary of the Glenelg River near the South Australian border, the Mosquito Creek unit is surrounded by plains (Apsley) and undulating sand plains (Powers Creek) that lead into the Glenelg River. There are four landscape components dominated by a level sand plain. The other minor components are gentle drainage slopes, drainage lines and swamp beds. Drainage will vary according to distance from drainage lines as well as slope and source area (hydraulic head). Soil types are predominantly yellow, brown and grey sodic texture contrast soils (

Sodosols

), with grey cracking clay soils in the depressions. Sheet and rill erosion are associated with the lighter topsoils and exposed surfaces. Waterlogging and salinity in the depressions and broader flats are also an issue. Grazing (sheep and cattle) is the dominant enterprise along with dryland cropping. Most vegetation communities (Creekline Sedgy Woodland, Riparian Woodland, Damp Heathland, Plains Sedgy Woodland and Red Gum Wetland) are associated with wetter areas including swamps and creeklines. Other vegetation communities include woodlands.

Swamp sand plain and centre pivot irrigator
	Sheep grazing on sand plain

Component	1	2	3	4
Proportion of soil-landform unit	65%	15%	10%	10%
CLIMATE Rainfall (mm)	Annual: 635
CLIMATE Rainfall (mm)	Annual: 635
Temperature (^oC)	Minimum 8, Maximum 20
Precipitation less than potential evapotranspiration	October–April
GEOLOGY Age and lithology	Quaternary aeolian dune sand, paludal silt and clay; Neogene marine sand and silt (Parilla Sand); Neogene marine sand, sandstone, silt and laterite (Dorodong 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 and cattle grazing
LANDUSE
TOPOGRAPHY Landscape	Swampy sand plains
TOPOGRAPHY Landscape	Swampy sand plains
Elevation range (m)	95–161
Local relief (m)	3
Drainage pattern	Dendritic
Drainage density (km/km²)	0.5
Landform	Sand plains	Swamps and drainage systems
Landform element	Level plain	Gentle drainage slope	Drainage line	Swamp bed
Slope and range (%)	0 (0-1)	2 (1-5)	0 (0-2)	0 (0-1)
Slope shape	Straight	Linear	Concave	Concave
NATIVE VEGETATION Ecological Vegetation Class	Plains Woodland (38.2%), Shallow Sands Woodland/Plains Sedgy Woodland/ Seasonally Inundated Shrubby Woodland/Damp Sands Herb-rich Woodland Mosaic (19.7%), Creekline Sedgy Woodland (17.4%), Other (24.7%)
NATIVE VEGETATION Ecological Vegetation Class
SOIL Parent material	Marine sand and silt, aeolian dune sand	Marine sand and silt, aeolian dune sand	Marine sand and silt	Paludal silt and clay
SOIL Parent material	Marine sand and silt, aeolian dune sand	Marine sand and silt, aeolian dune sand	Marine sand and silt	Paludal silt and clay
Description (Corangamite Soil Group)	Sodic brown, yellow and grey texture contrast soils (38)	Sodic brown, yellow and grey texture contrast soils (38)	Grey and brown cracking clay soils (37)	Grey and brown cracking clay soils (37)
Soil type sites	LSWW11, LSWW17, LSWW13	LSWW11, LSWW17, LSWW13	LS3, LSWW9, LSWW5	LS3, LSWW9, LSWW5
Surface texture	Loamy sand	Loamy sand	Medium clay	Medium clay
Permeability	Slow	Moderate to slow	Very slow	Very slow
Depth (m)	1.3	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 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 seasonal inundation and waterlogging especially depressions. Surface soils friable and only slightly susceptible to wind erosion. Soils susceptible to compaction at critical moisture contents.	Susceptible to 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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