Smartline glossary

The following glossary explains in broad terms the usage of a number of key terms found in the Smartline search windows or in other text on these web pages. Users should note that in some cases the definitions given here may differ from those used elsewhere for the same terms. In particular, the meanings adopted here for certain terms including “sensitivity” and “vulnerability” follow those of the Allen Consulting Group Report (Allen 2005) and the Intergovernmental Panel on Climate Change (IPCC), which differ from some other usages of those terms.

A |  B |   C |   D |   E |   F |   G |   H |   I |   L |   M |   O |   P |   Q |   R |   S |   T |   U |   V |   W |

A


ABSAMP

Australian Beach Safety and Management Database. Database created by Surf Life Saving Australia (SLSA), which incorporates geomorphic data compiled by Prof. A. Short for all Australian beaches.


Accretion

Addition, deposition or accumulation of sediment. In effect, the opposite of erosion.


Aggradation

Upwards accumulation and growth of a sediment deposit.


AHD

Australian Height Datum. Theoretically this datum is intended to lie at mean sea level, however ongoing sea-level rise means that AHD now lies a little below mean sea level in many areas.


AMSA

Australian Maritime Safety Authority. Agency responsible for the production of the Oil Spill Response Atlas (OSRA), from which significant amounts of coastal geomorphic mapping was incorporated into the Smartline.


Arenite

Sand-grade lithified sedimentary rock (e.g., sandstone, calcarenite, etc).

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B


Beach ridges

Generally multiple shore-parallel ridges inland of a shoreline which formed during rapid progradation of a sandy shore. Beach ridges are not properly dunes, but rather stranded beach berms. However in some cases they may be composite features, where wind-blown sand has accumulated on a beach ridge after it has been isolated from ongoing wave action due to continued seawards growth of the beach in front of the ridge.


Berm

A distinct change of slope on a beach, marking the landwards limit of recent wave action. On some beaches the berm is composed of coarser material (e.g., cobbles) deposited during storms.

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C


Calcarenite

Sand-grade lithified sedimentary rock composed of cemented calcium carbonate grains (i.e., a type of limestone). On the Australian coast, many prominent calcarenite deposits are Holocene or Pleistocene coastal dunes of carbonate-dominated sand cemented by groundwater processes. Calcarenites vary from very hard tough rocks to soft friable sandy rocks. They are classified as 'hard rock' types by default in the Smartline geomorphic classification, unless specific occurrences are known to be soft.


Chenier

Beach ridge of relatively coarser sediment deposited over substrate of relatively finer sediment; multiple origins likely in different places, some may be storm deposits.


Colluvium

Slope deposits. Deposits of boulders, cobbles and finer material that have accumulated on slopes as a result of erosion and movement of material from higher levels. Many colluvial deposits in Tasmania formed under the more sparsely-vegetated conditions of the last glacial climatic phase.

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D


DEM

Digital Elevation Model. A widely used GIS format which represents surfaces (e.g., of land) as a grid, each cell of which has a defined location and elevation.


Department of Climate Change (DCC)

The Australian Commonwealth Government Agency concerned with mitigation of and adaptation to global climate change. Formerly the Australian Greenhouse Office.


Dune

A landform composed of unconsolidated sediment (generally sand) transported and deposited by wind. Dunes may form at inland sites but are a characteristic feature of sandy coasts (where dunes initially build above the high water mark from sand blown off a beach by onshore winds), but may occur in other rocky coastal situations such as cliff-top dunes, where the original source of sand is no longer apparent.


Dunefield

Multiple dunes that may extend hundreds of metres or even kilometres inland of a shoreline. Coastal dune fields commonly comprise multiple parabolic or transgressive dunes formed by erosion and re-mobilisation of sand initially deposited in foredunes, to form mobile sand bodies migrating inland away from the coast.

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E


Erosion

Removal of material (e.g., from a sediment body or landform) by natural processes (e.g., wave action). See also 'Recession'.


Exposure

The term 'exposure' is used in two different contexts in this work:

  1. In relation to Smartline geomorphic attributes, 'exposure' is used as an indicator of the degree to which a shoreline segment receives whatever swell-wave energies impinge on the broader coastal region of which the segment is part.
  2. In relation to risk and hazard terminology, 'exposure' here refers to the degree to which a hazard (e.g., storm waves) actually impact on a given coastal site.

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F


Fabric

For the purposes of the Smartline coastal landform map, 'fabric' refers to the constituents of a landform, or the types of material they are made of. Fabric types are classified by degree of lithification and grainsize; thus example fabric classes include: hard rock, soft rock, sand, mud, coarse sediment, etc.


Flood – tide delta

A sediment deposit (usually sand) that has accumulated in a coastal lagoon or re-entrant, at the landwards end of a tidal channel or re-entrant mouth through which tidal currents transport sand.

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G


Geomorphology

The study of landforms, their forms, genesis, development and processes.


Geomorphic

Pertaining to geomorphology (see above).


Geoscience Australia (GA)

The Australian Commonwealth government agency concerned with the geo-sciences, including geological, geomorphic, geographic and topographic mapping and geohazard assessment functions.


GIS

Geographical Information System. Digital mapping and analysis of mapped information, including point, line & polygon vector data, raster & image data, and Digital Elevation Model (DEM) formats.


Glacial phase

A relatively cool period of Earth history during which significant expansion of glaciers and ice caps occurs, and sea level drops significantly. Multiple glacial phases have occurred during the last few million years. The Last Glaciation peaked about 22,000 to 17,000 years ago, and ended about 10,000 years ago.


Greenhouse Office, The (AGO)

See 'Department of Climate Change'.

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H


Hazard

In the context of coastal vulnerability, a 'hazard' is a natural process (e.g., sea-level rise, storms) which has the potential to impact on susceptible coasts to a degree which may place valued assets at risk.


Holocene

The stage of geological time between the end of the Last Glaciation (about 10,000 years ago) and the present. The Holocene effectively equates to the present interglacial climatic phase.

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I


Interglacial phase

A relatively warm period of Earth History, between glacial phases, when glaciers and ice caps retreat and sea level rises significantly. The Earth is currently in an interglacial phase, and the last (previous) interglacial phase occurred around 125,000 years ago.


IPCC

Intergovernmental Panel on Climate Change. An international organisation established in 1988 by the World Meteorological Organisation and the United Nations Environment Programme, for the purpose of reviewing and reporting on the current state of scientific understanding of and research into global climate change and its effects, including sea-level rise.

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L


Laterite

A well-developed ferruginous weathering layer or deposit, typically developed on the surface of a bedrock or sediment unit of which the laterite horizon is the highly weathered and altered product. Commonly exposed by coastal erosion in northern Australia; may also be exposed in southern Australia but more likely to be older 'fossil' laterites in that region.


Lithic, Lithified

For the purposes of this report refers to in situ indurated, consolidated, cemented or rocky materials (generally hard, albeit some may be relatively soft by reason of being weathered or only semi-lthified).


Lithification

The geological processes whereby a soft sediment becomes a hard, tough rock over a period of time. Lithification processes include compaction of the sediment and the precipitation of chemical cements from groundwater.


Littoral drift

Movement of sediment (e.g., sand) along a shore in the near-shore zone, usually resulting from along-shore currents generated by wave action.


Lutite

Very fine-grained (silt / mud / clay grade) lithified sedimentary rock (e.g., mudstone, siltstone, shale, etc).

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M


Mangroves

These are an intertidal vegetation community common around much of the Australian coast. Because mangroves very commonly occupy broad muddy tidal flats (and contribute to the formation and maintenance of such flats by trapping sediment), the term 'mangroves' is commonly used to refer to the muddy tidal flat landform as well as the vegetation type. However this is incorrect usage because mangroves are a vegetation type not a landform type. Moreover, mangroves can and do also grow on sandy or rocky coasts, hence the Smartline geomorphic classification system classifies mangrove coasts by their landform type, leaving vegetation type mapping to be provided in purpose-designed vegetation maps.


MHWM

Mean High Water Mark, i.e., the mean of high water over a long period of time.


MLWM

Mean Low Water Mark, i.e., the mean of low water over a long period of time.

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O


OSRA

The Oil Spill Response Atlas, maintained by the Australian Maritime Safety Authority (AMSA). This dataset comprises digital mapping of a wide variety of coastal features and attributes, including shoreline type (landform) mapping which has been used in preparation of the Smartline coastal landform map.

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P


Pleistocene

The stage of geological time spanning most of the last 2 million years up until the end of the Last Glaciation 10,000 years ago. The Pleistocene has been marked by a succession of glacial and interglacial climatic phases which have caused sea level to repeated rise and fall over a vertical range of about 130 metres, and have exerted a strong influence on coastal landform development globally.


Post-glacial marine transgression

In this report, the period of relatively rapid and continuous global sea-level rise following the maximum intensity of the last glacial climatic phase (circa 22,000 to 17,000 years ago), when sea level rose by about 130 metres before stabilising close to its present level about 6,500 years ago.


Progradation

Seawards growth or accretion of a shoreline by addition of sediment, usually where the sediment budget involves a predominance of sediment supply and accretion over erosion.

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Q


Quaternary

The period of geological time spanning most of the last 2 million years up to and including the present. The Quaternary Period is sub-divided into the Pleistocene (older) and Holocene (recent) stages.

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R


Recession

Opposite to progradation: landwards movement of a shoreline due to removal of sediment or rock material by erosion.


Return period

Average period of time between occurrences of a specified type of event. It is important to note that the return period is an average period only; i.e., a 50-year return period event does not necessarily occur regularly every 50 years. For example, two 50-year return period events could occur in one year, then not for another 100 years.


Rudite

Coarse grained (pebble / cobble / boulder grade) lithified sedimentary rock (e.g., conglomerate, breccia, tillite).

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S


Saline flats saltpans

In coastal regions, low-profile areas with significant surface salt precipitates. Commonly occur on 'supratidal' flats which are occasionally (but not frequently) inundated by the sea (e.g., during storm surges).


Sediment budget

The balance between the supply of sediment (e.g., sand) to a shore and the erosion or removal of sediment from that shore.


Semi-lithified

Refers to sediments which are coherent and partly "turned to rock" (lithified) by processes of compaction and the precipitation of chemical cements by groundwater, yet remain softer and more erodible than a fully lithified rock.


Sensitivity

In this context, the susceptibility of coastal landforms to the impacts of coastal hazards such as sea-level rise and storm waves. Such impacts may include physical instability (erosion, progradation) and/or inundation. Note that dome workers use “vulnerability” in the sense that 'sensitivity' is used here; in contrast, 'vulnerability' is now used here in a broader sense (see “vulnerability”).


SLSA

Surf Life Saving Australia; National organisation which funded geomorphic studies of all Australian beaches by Prof. Andy Short, and the compilation of this data into the ABSAMP database (see above).


Stability

The susceptibility or sensitivity of coastal landforms to physical change (erosion, progradation, etc); in this sense the term is used in a narrower sense than 'sensitivity', which encompasses both the susceptibility of coastal landforms to physical change and also to other impacts such as inundation. Thus, the stability of a landform depends primarily on its fabric (hard or soft constituents) and only secondarily on its topography (steep, low-lying, etc), whereas its sensitivity to inundation may depend primarily on its topography.


Storm surge

A temporary increase in sea level at the shore due to a combination of low barometric pressures and energetic onshore wind and waves. The magnitude of a storm surge is also strongly dependant on the tidal phase at the time of the peak surge.


Supratidal

Areas above the High Water Mark which are (only) occasionally inundated by the sea (e.g., during storm surges). Classified as a “Backshore” landform area for the purposes of the Smartline Geomorphic classification.


Susceptibility

Equivalent to the meaning of "Sensitivity" as given above, more commonly used in this sense in the geomorphic literature than is "susceptibility", and sometimes used interchangeably with "sensitivity" in this report.

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T


Talus

A variety of colluvium (slope deposits) typically comprising loose boulders and cobbles that have fallen, rolled or slid from an escarpment and accumulated below.


Tides, Tidal

Variation in sea surface levels, typically on a daily cycle, owing to the gravitational influence of the moon and sun. Tidal levels may vary considerably owing to local barometric pressures, wind stress and other factors.


Transgression

In relation to the sea, a phase during which the sea rises or "transgresses" over formerly dry land.


Translation

In coastal geomorphology: horizontal movement of a feature, for example of a coastal sand barrier as a result of erosion on one side and accretion on the other.

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U


Unconsolidated, Unlithified

Refers to sediments that remain more-or-less loose or friable, not formed into hard rock by geological processes such as compaction and precipitation of cements from groundwater.


Undiff, Undifferentiated

Not divided into sub-types or sub-classes. For example, an 'undifferentiated sedimentary rock' is one which has only been identified as some type of sedimentary rock, but the specific type (e.g., sandstone, mudstone, conglomerate, etc) has not been determined.

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V


Vulnerability

In this context, vulnerability (or its converse, 'resilience') means the degree to which a society or natural system is or is not capable of adapting or responding to the impacts of the coastal hazards to which they are physically sensitive and exposed. Note however that the term vulnerability is also commonly used in the sense that 'sensitivity' is used here.

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W


Weathered, Weathering

The process by which hard lithified rock is broken down by mechanical, thermal and chemical processes into soft or friable materials susceptible to erosion. Note that materials that are chemically weathered (leached) and transported by groundwater may subsequently re-precipitate as laterites, 'duricrusts', hard-pans, 'coffee rock' or other products of weathering processes.

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