Australian Natural Resources Atlas

Natural Resource Topics

Australian Catchment, River and Estuary Assessment 2002

National Land and Water Resources Audit, 2002
ISBN 0 642 37125 3

Glossary

Abstraction
Permanent removal of water from a stream channel.
Algal bloom
Proliferation of one or more phytoplankton species to high densities under favourable environmental conditions.
Alluvial
Relating to material deposited by running water.
Anaerobic
Environmental conditions where free oxygen is absent.
Aquatic ecosystem/system
Any body of water including lakes, streams, wetlands, reservoirs or estuaries and associated living organisms and non-living components functioning as a natural system.
Aquifer
A geological formation, group of formations, or part of a formation that stores and/or allows movement of groundwater.
Bank
The relatively steep part of a river channel, generally thought of as being above the usual water level.
Bank full
The carrying capacity of a stream just prior to its spilling onto the adjacent area.
Bed load
The solids that are carried within the bed of a river, excluding those carried in suspension or solution; they range from the heavier particles, which are moved by saltation (leaping movement), to the largest, which are moved by traction. The bed load has two sources: hillside material washed into a stream and material produced by erosion of river banks.
Bed, river
That part of a river channel usually covered with water when the river is flowing.
Bedrock
The natural, more or less undisturbed country/parent rock.
Benthic zone
The bottom or bed of a water body.
Biota
Refers to all plant and animal life in an area.
Biodiversity
Variety of life forms including the different plants, animals and microorganisms, the genes they contain and the ecosystems they form. Biodiversity is usually considered at three levels: genetic, species and ecosystem.
Biophysical
Relating to biological and physical processes.
Braided
Refers to streams that divide into an interlacing network of several branching and reuniting channels separated from each other by islands or channel bars.
Catchment
An area that drains all the precipitation that falls on it to a single point. Or the area of land drained by a stream or stream system. It can be simple, dealing with the water of one watercourse, or complex, having a number of internal subcatchments contributing to the whole. Catchment should not to be confused with watershed.
Condition
The state of a system that is defined relative to some ideal benchmark.
Connectivity, lateral
A river's connection with the floodplain and the movement of water, biota and material across the floodplain. Levees disrupt lateral connectivity.
Connectivity, longtitudinal
The upstream-downstream connectivity that is important for the migration and breeding of many fish species. Built structures disrupt longtitudinal connectivity.
Dam
An impediment, natural or artificial to the general flow of a stream, usually built for storage.
Deposition
The settling out or laying down of suspended, in-solution or other water-borne materials by a lessening of the velocity of the water or changes in water chemistry.
Detention basin
A basin (constructed or natural wetland) that temporarily detains surface run-off or flood waters.
Detritus
Organic marterial such as leaves and twigs.
Dike, bund, bund wall
An embankment for controlling water; any impoundment structure that completely spans navigable water.
Disturbance
A force that causes changes in habitat or community structure and composition such as natural events or human activities.
Diversion
Any natural or artificial method or means by which a part or whole of a river flow is taken from its natural course.
Drainage area
The country drained by a stream system. See catchment, drainage basin.
Drainage basin
See catchment or river basin.
Drainage division
Drainage divisions are broad regions of the Australian continent defined by aggregation of adjoining river basins with comparable climate or geography or shared discharge points.
Dredging
A mechanical operation that may use heavy machinery to remove river material to improve the channel or as part of a mining operation.
Driver, biophysical or process
Biophysical elements or processes that determine the patterns and fluxes of biota, material and energy within ecosystems. Changes to these elements or processes 'drive' the ecosystem to a different condition.
Dry sheep equivalent
A standard unit frequently used to compare the feed requirements of different classes of stock or to assess the carrying capacity and potential productivity of a given farm or area of grazing land. It is based on the amount of feed required by a two year old, 45 kg Merino sheep (wether or non-lactating, non-pregnant ewe) to maintain its weight.
Ecological sustainability
Maintenance of ecosystem and species stability over human time scales.
Ecosystem
Community of organisms that may include humans, interacting with one another. Incorporating the physical, chemical and biological processes inherent in that interaction and the environment in which they live.
Ecosystem health
A term used to describe desired ecosystem conditions. the perception of health will vary depending on goals (i.e. production versus biodiversity).
Embankment
The artificial bank built along a river to protect adjacent land from flood waters. Also called levee or dike.
Endemic
Species that is unique or confined to a specific locality.
Environmental water provisions
Water allocated to support the ecological functioning of aquatic and other dependent habitats based on environmental, social and economic considerations, including existing user rights.
Environmental water requirements
Descriptions of the flow regimes (e.g. volume, timing, seasonality, duration) needed to sustain the ecological values of aquatic ecosystems including their processes and biological diversity.
Estuary/coastal waterway
For the Audit assessment, estuaries and coastal waterways are broadly described as a semi-enclosed coastal water body where salt from the open sea mixes with freshwater draining from the land or where marine and fluvial sediments occur together.
Eutrophication
Process of enrichment of nutrients, especially nitrogen and phosphorous.
Extensive land use zone
The area of Australia that does not contain intensive land use. Broadly referred to as the rangelands.
Fish ladder, passage
Inclined waterway, commonly an artificial channel with stepped pools installed at a dam to allow passage of migratory fish over or around an obstruction.
Flushing rate
Time required for a volume of water equivalent to the estuary volume to mix with the ocean or the reservoir volume to be discharged.
Fluvial
Relating to or occurring in a river.
Flood plain
The flat area usually toward the lower end of a river system where periodic flooding has deposited river-borne materials.
Flow duration
Percentage of time within a given period when different flows occur.
Gauging station
Location where measurements of stream flow are made.
Geomorphic
Pertaining to form or shape of the landscape and the processes that affect the Earth's surface.
Geomorphology
Science of describing and interpreting landform and processes of landscape formation.
Groundwater
Water stored underground in rock fractures and pores.
Groyne
A structure built from the bank of a river in a transverse direction to the current. Its function is to assist in keeping the eroding current away from an affected bank and in so doing to promote deposition of silt and other material along the bank in its vicinity.
Gully
A narrow channel worn in a hillside or on sloping ground by the action of water and particularly by accelerated erosion. It is usually dry except after rain.
Habitat
A specific type of place within an ecosystem occupied by an organism, population or community that contains both living and non-living components with specific biological, chemical and physical characteristics including life requirements (e.g. food, shelter and water).
Hydrologic regime
Water movement in a given area. It is a function of input from precipitation, surface and groundwater and output from evaporation into the atmosphere or transpiration from plants.
Impoundment
A natural or artificial body of water that is confined by a structure such as a dam.
Inshore marine
In or on marine water, but close to the shore.
Intensive land use zone
The area of Australia where intensive land use practices such as irrigated agriculture occur.
Intertidal
The zone of shore between the high water mark and low water mark.
Integrated catchment management
A management process that takes account of all aspects of a catchment. Although defined slightly differently in each State, the goal of integrated catchment management (or total catchment management) is usually to ensure the sustainable development of natural resource-based industries, the protection of land, water and vegetation resources and the conservation of natural and cultural heritage on a river or groundwater catchment basis.
Inverse estuary
Type of estuary where evaporation exceeds freshwater inflow plus precipitation.
Landtype
Unit on the Earth's surface of a characteristic geomorphic surface type and a particular lithilogical composition, identifiable on a scale of hecatares.
Levee
Natural or artificial ridge or embankment to prevent flooding or restrict movement of water.
Littoral drift
River mouths at coastlines suffer a gradual and continual change due to wind and wave action which may cause deposition across the mouth. Usually the principal source of bar material.
Macro-invertebrate
An animal without a backbone and large enough to be seen without magnification.
Macrophyte
A plant that can be seen without magnification.
Mean flow, average discharge, average daily flow, average annual flow
Average discharge at a given stream location.
Natural flow
Discharge that occurs naturally through climate and geomorphology without regulation and diversion or other modification.
Outfall
Outlet of a water body, drain or culvert.
Oxbow
Bend or meander in a stream that becomes detached from the stream channel. Also known as 'billabong'.
Protective management
Management activities focussed on maintaining natural resources in good condition as opposed to those that seek to rehabilitate condition.
Rehabilitation, remediation
Action to return a landform, vegetation, or water body to as near as original condition as practical. Implies making land and water resources useful again after disturbance.
Remote sensing
Acquisition of information on an object by satellite, aerial photography and radar.
Retention
Portion of the gross storm rainfall that is intercepted, stored or delayed in wetlands or constructed basins to allow nutrients and sediment loads to settle out.
Riffles
Shallow reaches with low flow characterised by small hydraulic jumps over rough bed material, causing small ripples, waves and eddies, without breaking surface tension.
Rill erosion
Erosion resulting from movement of soil by a network of small, shallow channels.
River basin
Catchment areas of major rivers draining to the sea; named after these rivers. The 245 river basins as defined by the former Australian Water Resources Council. These form sub-basins of the drainage divisions.
River reach
A group of river segments with similar biophysical characteristics.
Run-off
The difference in quantity between precipitation and the combination of evaporation and transpiration. The resulting water that supplies rivers and lakes after evaporation and transpiration have occurred. Includes water that soaks into the earth and is available as groundwater. Surface run-off does not include groundwater.
Seasonal amplitude
Measure of the difference between seasonally high and low flows.
Seasonal period
The return time between certain flow conditions.
Sediment carrying capacity
The capacity of a stream to transport sediment both as bed load and in suspension. It is related to flow gradient, velocity and volume.
Sedimentary environment
Refers to a characteristic suite of sediment types defined by mineralogical composition and grain size that are deposited within specific landform and energetic environments. Also known as 'sedimentary facies'.
Sheet erosion
Erosion of soil from across a surface by uniform action of rain or flowing water.
Supratidal
The zone of shore between the mean high water mark and the astronomical high water (spring tide) mark.
Watershed
The boundary of a catchment, the dividing line between two catchments. Often erroneously used instead of catchment.
Waterway
A general term for any stream, river or watercourse, either flowing or dry. Also includes artificial cuts, canals and channels.

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