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Coastal sand masses (high dunes)

High dunes

Fish Dugong Corymbia spp Acacia spp Corymbia spp Sand saturated with fresh groundwater Sand saturated with fresh groundwater Low permeability rock Low permeability rock Low permeability rock Low permeability rock Low permeability rock Low permeability rock Low permeability rock Low permeability rock Low permeability rock Fresh groundwater and marine groundwater interface Direction of marine groundwater movement Direction of marine groundwater movement Fresh groundwater and marine groundwater interface Negligible groundwater movement Negligible groundwater movement Groundwater table Fresh groundwater and marine groundwater interface Direction of marine groundwater movement Fresh groundwater and marine groundwater interface Direction of groundwater movement Direction of groundwater movement Direction of groundwater movement Direction of groundwater movement Direction of groundwater movement Direction of groundwater movement Direction of groundwater movement Direction of groundwater movement Direction of groundwater movement Infiltration and percolation Infiltration and percolation Infiltration and percolation Surface expression GDE Surface expression GDE Surface expression GDE Terrestrial GDE Terrestrial GDE Surface expression GDE (estuarine systems) Subterranean GDE Surface expression GDE (near-shore marine systems) Patterned fens Surface expression GDE Marine GDE dependent on reefs GDEs dependent on perched groundwater Intemittently closed and open lakes and lagoons (ICOLLs) Infiltration and percolation Direction of groundwater movement Groundwater table Negligible groundwater movement Low permeability rock Sand saturated with saline and fresh groundwater Sand saturated with fresh groundwater Variable groundwater leakage Low permeability rock Sand Sand Corymbia spp Acacia spp Corymbia spp Eucalyptus spp Melaleauca spp Cladium spp Eleocharis spp Cladium spp Eucalyptus spp Corymbia spp Basement of the model Sand (saturated with marine water)

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Coastal sand islands with high dunes usually contain one or more unconfined, unconsolidated sedimentary aquifers, where groundwater is stored and transmitted through inter-granular voids between sand particles. These unconsolidated sedimentary aquifers may be perched due to the presence of low permeability layers within the coastal sand mass (e.g. layers of coffee rock or beach rock). Examples of coastal sand islands with high dunes along the Queensland coast include Fraser, Moreton and North Stradbroke islands.

A wide range of ecosystems may depend on groundwater in these unconsolidated sedimentary aquifers to support their plant and animal communities, ecological processes and delivery of ecosystem services.

  • Palustrine (e.g. swamps) and lacustrine (e.g. lakes) wetlands and riverine (e.g. streams and rivers) water bodies on coastal sand masses may depend on the surface expression of groundwater from these unconsolidated sedimentary aquifers. In general, the regional aquifer sustains stream flow in lower parts of the landscape and perched aquifers may supplement streams higher in the landscape.
  • Terrestrial vegetation on coastal sand masses, usually in lower parts of the landscape or at low altitudes, may depend on the sub-surface presence of groundwater in these sand mass aquifers where groundwater is typically accessed through the capillary zone above the water table.
  • Unconsolidated sedimentary aquifers may also support subterranean ecosystems within the aquifer itself, which sometimes is indicated by the presence of stygofauna.
  • Estuarine and near-shore marine ecosystems located adjacent to coastal sand masses may depend on the discharge of groundwater from these unconsolidated sedimentary aquifers.

Pictorial conceptual model PDF


Last updated: 18 December 2015

This page should be cited as:

Coastal sand masses (high dunes), WetlandInfo 2013, Queensland Government, Queensland, viewed 12 September 2017, <https://wetlandinfo.ehp.qld.gov.au/wetlands/ecology/aquatic-ecosystems-natural/groundwater-dependent/coastal-sand-mass-high-dunes/>.

Queensland Government
WetlandInfo   —   Department of Environment and Heritage Protection