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Alluvia—upper catchment

Alluvia—upper catchment (wet)

Infiltration and percolation Infiltration and percolation Moderate to high permeability rock (unsaturated) Melaleuca spp Permeable rocks Infiltration and percolation Eucalyptus spp Terrestrial GDEs Evapotranspiration Direction of groundwater movement Direction of groundwater movement Negligible groundwater movement Infiltration and percolation Groundwater table Groundwater table Direction of surface water run-off Direction of surface water run-off Direction of surface water run-off Subterranean GDEs Surface expression GDEs Fish Gravel - often found along the channel bed Groundwater discharge - surface and groundwater interaction Variable groundwater leakage in direction indicated Fauna Moderate to high permeability rock (saturated) Direction of surface water run-off in channel Direction of surface water run-off Direction of surface water run-off Moderate to high permeability rock (unsaturated) Eucalyptus spp Eucalyptus spp Melaleuca spp Clouds and rainfall Permeable rocks Melaleuca spp

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Upper catchment areas with little alluvial development

In upper catchments alluvial aquifers are formed from particles such as gravel, sand and minor silt or clay deposited by physical processes in channels. Alluvia may contain unconfined, unconsolidated sedimentary aquifers, where groundwater is stored and transmitted through intergranular voids between gravel and sand particles. In upper catchments channels may have little or no alluvial development, groundwater may move through surrounding permeable rocks into the limited alluvia present and discharge into channels.

Unconsolidated sedimentary aquifers in upper catchment areas may provide a range of ecosystems with water required to support their fauna and flora communities, ecological processes and delivery of ecosystem services.

  • Palustrine (e.g. swamps), lacustrine (e.g. lakes) and riverine (e.g. streams and rivers) wetlands may depend on the surface expression of groundwater from these unconsolidated sedimentary aquifers which are supported by surrounding permeable rocks.
  • Terrestrial vegetation fringing channels on alluvia may depend on the subsurface presence of groundwater in these unconfined, sedimentary aquifers.
  • Unconsolidated sedimentary aquifers in alluvial deposits may also support ecosystems within the aquifer itself, which sometimes is indicated by the presence of stygofauna.

PDF version

Alluvia—upper catchment (dry)

Direction of groundwater movement Moderate to high permeability rock (unsaturated) Melaleuca spp Permeable rocks Eucalyptus spp Direction of groundwater movement Subterranean GDEs Fish Gravel - often found along the channel bed Groundwater discharge - surface and groundwater interaction Variable groundwater leakage in direction indicated Fauna Moderate to high permeability rock (saturated) Moderate to high permeability rock (unsaturated) Eucalyptus spp Eucalyptus spp Melaleuca spp Permeable rocks Melaleuca spp Alluvia (saturated) Alluvia (unsaturated) Drier periods of time

Click on elements of the model or select from the tabs below

Upper catchment areas with little alluvial development

In upper catchments alluvial aquifers are formed from particles such as gravel, sand and minor silt or clay deposited by physical processes in channels. Alluvia may contain unconfined, unconsolidated sedimentary aquifers, where groundwater is stored and transmitted through intergranular voids between gravel and sand particles. In upper catchments channels may have little or no alluvial development, groundwater may move through surrounding permeable rocks into the limited alluvia present and discharge into channels.

In drier months the groundwater table usually drops below the surface resulting in little or no baseflow. There may be some residual pools trapped by low permeability layers beneath the channels.

Unconsolidated sedimentary aquifers in upper catchment areas may provide a range of ecosystems with water required to support their fauna and flora communities, ecological processes and delivery of ecosystem services.

  • Palustrine (e.g. swamps), lacustrine (e.g. lakes) and riverine (e.g. streams and rivers) wetlands may depend on the surface expression of groundwater from these unconsolidated sedimentary aquifers which are supported by surrounding permeable rocks.
  • Terrestrial vegetation fringing channels on alluvia may depend on the subsurface presence of groundwater in these unconfined, sedimentary aquifers.
  • Unconsolidated sedimentary aquifers in alluvial deposits may also support ecosystems within the aquifer itself, which sometimes is indicated by the presence of stygofauna.

Pictorial conceptual model PDF


Last updated: 18 December 2015

This page should be cited as:

Alluvia—upper catchment, WetlandInfo 2013, Queensland Government, Queensland, viewed 14 December 2018, <https://wetlandinfo.des.qld.gov.au/wetlands/ecology/aquatic-ecosystems-natural/groundwater-dependent/alluvia-upper/>.

Queensland Government
WetlandInfo   —   Department of Environment and Science