State of the Environment

2001

Inland Waters Theme Report

Australia State of the Environment Report 2001 (Theme Report)
Prepared by: Jonas Ball, Sinclair Knight Merz Pty Limited, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06750 7

Glossary

algal blooms
a sudden proliferation of microscopic algae in water bodies, stimulated by the input of nutrients such as phosphates.
aquatic ecosystem
all living and non-living elements, and the relationship between them, of a water-based environment.
aquifer
an underground layer of soil, rock or gravel able to hold and transmit water. Bores and wells are used to obtain water from aquifers.
baseflow
flow in rivers and streams that occurs in dry weather and usually from groundwater inflows.
biodiversity
the variety of life forms, the different plants, animals and microorganisms, the genes they contain and the ecosystems they form.
biophysical
jointly refers to the biological and physical elements of an environment.
blue-green algae
an ancient order of algae (that have some characteristics of bacteria) that have become more common in water bodies due to disturbance and pollution. Some species produce toxins that can cause sickness, nerve and liver damage.
bore capping
temporary or permanent closure of a discharging bore.
catchment
the area of land drained by a river and its tributaries.
catchment management committees
committees of community and government representatives set up to develop and implement plans related to water and land management.
conjunctive use
management of water as an integrated groundwater and surface water resource. Surface water and groundwater systems are often interconnected and cannot be managed separately.
cumulative impacts
the incremental effects of a group of actions as they accumulate over time and space.
developed yield
average annual volume of surface water that can be diverted for use with existing infrastructure. Developed yield represents the portion of the divertible yield that is currently available for use.
diffuse-source pollution
pollution from sources such as eroding agricultural, urban and forested lands. Run-off after rainfall is considered a major diffuse pollution source.
diversion
surface water diverted for use from the resources of a surface water river basin for supply to both within-basin and external basin consumers.
divertible yield
average annual volume of surface water that can be diverted utilising both existing infrastructure and potential infrastructure under ultimate level of development taking no account of environmental water requirements.
drainage division, region and basin
The drainage divisions are 13 areas based on drainage patterns covering the whole of the Australian continent and some other areas such as Protected Territories. Drainage regions (77 in number) and basins (245) are smaller sub-areas within a drainage division and are based on groups of rivers and individual rivers, respectively. The system of drainage divisions, regions and basins was defined by the former Australian Water Resources Council and more recently revised under the auspices of the Agriculture and Resource Management Council of Australia and New Zealand.
dryland salinity
salinity caused when the replacement of native vegetation with crops and pastures that have shallower roots and different water use requirements, leads to more water flowing into groundwater system and the increased mobilisation of salt. This saline water rises to near the ground surface in low-lying areas or at the break of slope, and/or flows underground directly into streams.
ecosystem
communities of organisms and their physical environment interacting as a unit.
ecosystem health
the ability of the aquatic ecosystem to support and maintain key ecological processes and a community of organisms with a species composition, diversity, and functional organisation as comparable as possible to that of undisturbed habitats within the region.
environmental water allocations
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 biodiversity.
ephemeral watercourse
watercourse that does not flow all the time.
eutrophication
process by which waters become enriched with nutrients, primarily nitrogen and phosphorus, which stimulate the growth of aquatic flora and/or fauna.
flow regime
pattern of water flow in a river or stream. In undeveloped rivers and streams flow regimes are related to climatic conditions. In regulated rivers (i.e. dammed rivers), flow regimes are often altered from natural patterns.
gigalitre (GL)
1000 megalitres or 1000 million litres.
Great Artesian Basin (or GAB)
a large store of underground water underlying the arid central and eastern regions of Australia.
groundwater
water that occurs beneath the ground held in or moving through saturated layers of soil, sediment or rock.
groundwater-dependent ecosystems
ecosystems that are dependent on groundwater for their existence and health.
groundwater management unit (GMU)
a hydraulically connected groundwater system that is defined and recognised by state and territory agencies. This definition allows for management of the groundwater resource at an appropriate scale at which resource issues and intensity of use can be incorporated into local groundwater management practices.
groundwater province
an area having a broad uniformity of hydrogeological and geological conditions identified as either predominantly sedimentary or fractured rock as defined by the former Australian Water Resources Council.
groundwater yield
see sustainable flows.
gully erosion
a form of erosion involving the formation of deep sided channels or gullies usually due to the removal of riparian vegetation.
hydrologic
relating to the distribution and movement of water.
indicators
any physical, chemical or biological characteristic used as a measure of environmental, social or economic conditions.
instream use
water in the river and streams for the maintenance of aquatic ecosystems and for aesthetic and recreational purposes.
irrigation salinity
a localised rise in the level of groundwater and the associated mobilisation of salt, caused by the application of large volumes of irrigation water, compounded by the replacement of native vegetation by plants with different water use patterns.
landscape
an area of land and its physical features. A term used to describe an area that has common features.
levee
a constructed embankment designed to prevent flooding.
macrophytes
aquatic plants such as reeds and bull-rushes.
megalitre (ML)
1 000 000 litres
mean annual flow
the average annual streamflow passing a specified point on a stream.
mean annual run-off
the streamflow generated as a result of direct precipitation on the area of interest.
Murray-Darling Basin Cap
refers to the limit that has been placed on the volume of water that can be diverted from the surface water resources of the Murray-Darling Basin, in accordance with the Murray-Darling Basin Ministerial Council decision in June 1995. The cap volume is limited to the amount of water that would have been extracted under 1993/94 levels of development and management rules.
O:E ratio/score
ratio of the observed number of macroinvertebrate families to the expected number of families for each test site.
pathogen
an agent (such as a virus, protozoa or bacteria) causing disease.
pH
a measure of the concentration of free hydrogen ions and reported over a logarithmic scale of 1 to 14.
point-source pollution
pollution from an easily discernable, single source such as a factory or sewage treatment plant.
primary treatment (wastewater)
the first step in sewage treatment to remove large solid objects by screens and sediment and organic matter by settlement.
recharge
the portion of rainfall or river flow that percolates down through the soil and rock formations to reach the groundwater.
regulated rivers
rivers whose flows are controlled by dams. The term regulation means that the flows along the length of the river are controlled or regulated by releases made from major dams to meet the needs of licensed uses.
riparian vegetation
plant communities on the fringes and adjacent to water bodies.
river salinity
increasing concentrations of salt in rivers and creeks caused by saline discharges from dryland, irrigation and urban salinity.
run-off
the portion of rainfall that is not immediately absorbed into the soil and which becomes surface flow.
salinisation
the process by which land becomes salt-affected.
salinity
the concentration of sodium chloride or dissolved salts in water, usually expressed in electrical conductivity (EC) units or milligrams of total dissolved solids per litre (mg/L TDS).
secondary treatment (wastewater)
after primary treatment, removal of biodegradable organic matter from wastewater by bacteria and other micro-organisms.
siltation
deposition of sediments from water in rivers, streams and dams.
surface water management area
areas defined by state and territory water management agencies for the purposes of reporting on surface water resources. The boundaries of the reporting units commonly coincide with the Australian Water Resources Council river basins. In a number of cases the reporting units represent subdivisions of these river basins.
sustainable flows
the limit on potentially divertible surface water that is allowed to be diverted from a resource after taking account of environmental values and making provision for environmental water needs.
sustainable yield (groundwater)
level of extraction measured over a specified timeframe that should not be exceeded to protect the higher value social, environmental and economic uses associated with the aquifer.
sustainable yield (surface water)
see sustainable flows.
tertiary treatment (wastewater)
after secondary treatment, the removal of nitrogen, phosphorus and other pollutants from wastewater.
turbidity
a measure of the extent to which the passage of light through water is reduced by suspended matter.
unincorporated area (UA)
a groundwater resource that is defined geographically by a groundwater province and excludes any designated groundwater management units within the groundwater province. Within the unincorporated area, low level input is required to provide effective management of the groundwater resource due to low levels of current or potential use or development.
water allocation
refers to the volume of water allocated for use either within or external to a surface water management area by way of licensing arrangements and formal entitlements to water.
water quality objectives
numerical concentration limits or requirements established to support and protect the designated environmental values of water at a specific site.
water use
volume of water used within a surface water management area irrespective of the source of the water resource.
wetlands
land areas along fresh and saltwater courses that are flooded all or part of the time, leading to the development of a characteristic suite of plant and animal communities and determining the type and productivity of soils.