Dealing with salinity in Wheatbelt Valleys - Department of Water

SOIL LANDSCAPE - VEGETATION RELATIONSHIPS FOR THE EASTERN WHEATBELT
The Yilgarn and Lockhart Rivers are the major flow systems of the Zone of Ancient Drainage. This
landscape is characterized by broad flat valley floors with salt lake chains, gently sloping valley sides,
some rock outcrop and extensive areas of undulating sandplain. Surface water flow is driven by large
rainfall events over all or part of the 2 water catchments.
Bettenay and Hingston (1964) described landscape surfaces for the Eastern Wheatbelt. These have
specific topographic characteristics, soil types and associated vegetation types.
Norpa: Deep depositional sandplain of the uplands often covered with Wodgil (Acacia neurophylla) on
acidic white sands or Grevillea/Banksia communities on yellow sands.
Ulva: Shallow, gravelly soil surface bordering sandplain where wind has eroded the sand. Allocasaurina
species growing in dense thickets is the predominant vegetation type.
Booraan: This surface marks the eroded edge of the upland and often occurs below lateritic
breakaways. Eucalyptus capillosa (Eastern white gum) is the predominant vegetation type in the
Eastern Wheatbelt.
Collgar: The distinctive sand over clay soil surface of the mid slopes covered with a variety of mallee
forms. This vegetation type merges with York gum, Salmon gum and sandplain vegetation communities.
Danberrin: The surface marked by the old soil mantle stripped to bedrock. The soil is usually shallow
brown sand over a sandy clay on the top of granite. The York gum (E. loxophloba) is the typical
vegetation type around rock outcrops.
Merredin and Belka: These are the 2 soil surfaces of the lower slopes to valley floor. Salmon gum (E.
salmonophoia) and Gimlet (E. salubris) are the predominant vegetation types. Merredin soils are
colluvial red-brown sandy clay loams occupying broad flat valley tributaries to major drainage lines.
Belka soils are grey alluvial sediments occupying magor river systems of the past.
Nangeenan: The surface dominated by Morrel (E. longicornis) vegetation is composed of fine powdery
aeolian loams and clays, originating from the floors of dry salt lakes. These areas are the depositional
phase of the Baandee and typically seen in a lunette or dune form.
Baandee: This surface represents the old drainage lines now infilled and reduced to a series of salt
lakes. An erosional phase has often exposed Tertiary remnants and occasionally country rock. Typically
the vegetation of these areas is saltbush (Atriplex spp) and blue bush (Maireana spp) with samphire
(Halosarcia spp) occupying the most saline areas.