Australian National Committee on Large Dams

An incorporated voluntary association of organisations and individual professionals with an interest in dams in Australia.

Barmah Choke

A narrow section of the River Murray that constrains the volume of water that can pass during major floods. During floods, large volumes of water are temporarily banked up behind the Barmah Choke, flooding the Barmah–Millewa Forest wetland system.

Barrages

Five low and wide weirs built at the Murray Mouth in South Australia to reduce the amount of sea water flowing in and out of the mouth due to tidal movement, and to help control water levels in the Lower Lakes and River Murray below Lock 1 (Blanchetown, South Australia).

Baseline

Conditions regarded as a reference point for the purpose of comparison.

Baseline diversion limit

The baseline limit of take from a sustainable diversion limit resource unit.

Basin governments

The Australian Government and the governments of New South Wales, Victoria, Queensland, South Australia and the Australian Capital Territory.

Basin states

New South Wales, Victoria, Queensland, South Australia and the Australian Capital Territory.

Basin water resources

Water resources within or beneath the Murray–Darling Basin, except for resources that are prescribed by the regulations and groundwater that forms part of the Great Artesian Basin.

Cap (the Cap on Diversions)

A limit, implemented in 1997, on the volume of surface water that can be diverted from rivers for consumptive use. Under the Basin Plan, the Cap is replaced by long-term average sustainable diversion limits.

Connectivity

Connections between natural habitats, such as between a river channel and adjacent wetland areas. Connectivity is a measure or indicator of whether a water body (river, wetland, floodplain) has water connections or flow connections to another body.

Constraints

Anything that affects the delivery of water for the environment. Constraints can be physical, such as low-lying bridges and river channel capacity; or operational, such as river rules or operating practices that affect when and how much water can be delivered.

Conveyance water

The water needed to physically run the river system. Extra water must then be supplied on top of the conveyance water in order to meet deliveries along the river system. The conveyance reserve is water set aside for the next year to minimise the risk of not having enough conveyance water. Water is set aside water for conveyance and critical human needs to safeguard fundamental water requirements during a drought more severe than the millennium drought.

Critical human water needs

Under the Water Act 2007 (the Water Act), the minimum amount of water required to meet core requirements of communities dependent on Basin water resources. The definition also includes non-human requirements that, if not met, would cause prohibitively high social, economic or national security costs.

Cultural flows (or cultural water flows)

Water entitlements legally and beneficially owned by the Aboriginal Nations of the Murray–Darling Basin. They are of sufficient and adequate quantity and quality to improve the spiritual, cultural, environmental, social and economic conditions of Aboriginal people.

Electrical conductivity (EC)

A unit of measurement for electrical conductivity (1 EC = 1 μS/cm) measured at 25 degrees Celsius. It is commonly used as an indicator of water and soil salinity (salt concentration). Water and soil salinity levels are measured by passing an electrical current between the two electrodes of a salinity meter. EC is influenced by the concentration and composition of dissolved salts. Salts increase the ability of a solution to conduct an electric current, so a high EC indicates a high salinity level. Fresh water above 800 EC becomes marginal for drinking; above 1,600 EC it is brackish; and above 4,800 EC it is saline.

Entitlement (or water entitlement)

The volume of water authorised to be taken and used by an irrigator or water authority. It includes bulk entitlements, environmental entitlements, water rights, sales water and surface water and groundwater licences.

Environmental flow

Any river flow pattern provided with the intention of maintaining or improving river health. Environmental water Water used to achieve environmental outcomes, including benefits to ecosystem functions, biodiversity, water quality and water resource health.

Environmental water requirement

The amount of water needed to meet an ecological or environmental objective.

Fishway

A structure that provides fish with passage past an obstruction in a stream.

Flow

The movement of water—the rate of water discharged from a source, given in volume with respect to time.

Flow event

A single occurrence of water flow in a river, sometimes required to achieve environmental targets. A series of flow events comprises a flow history.

Groundwater

Water occurring naturally below ground level (in an aquifer or otherwise).

Held environmental water

Water that is available under a water access right, a water delivery right or an irrigation right for the purpose of achieving environmental outcomes.

Inflow

The source of the water that flows into a specific body of water. For a lake, the inflow could be a stream or river; for a stream or river, the inflow could be rain.

Irrigator

An irrigator is a primary producer who uses river water to irrigate crops or water livestock.

Irrigation infrastructure operator

An irrigation infrastructure operator owns or operates water service infrastructure for delivering water for the primary purpose of irrigation.

Modelling

Application of a mathematical process or simulation framework (e.g. a mathematical or econometric model) to describe various phenomena and analyse the effects of changes in some characteristics on others.

Murray Lower Darling Rivers Indigenous Nations (MLDRIN)

Confederation formed in 1998 of Indigenous Nations from the southern part of the Basin. It comprises representatives of the Barapa Barapa, Barkindji (Paakantyi), Dhudhuroa, Dja Dja Wurrung, Latji Latji, Maraura, Mutti Mutti, Nari Nari, Ngarrindjeri, Ngintait, Nyeri Nyeri, Tatti Tatti, Taungurung, Wadi Wadi, Wamba Wamba, Waywurru, Wegi Wegi, Wergaia, Wiradjuri, Wolgalu, Wotjabaluk, Yaitmathang, Yita Yita and Yorta Yorta Nations.

Northern Basin Aboriginal Nations (NBAN)

Confederation formed in April 2010 that comprises Aboriginal Nation representatives from the northern part of the Basin and representatives from the New South Wales Aboriginal Land Council, the Queensland Murray–Darling Committee, the Condamine Alliance and South West Queensland Natural Resource Management. It comprises Traditional Owner nominated representatives from the Barkindji (Paakantyi), Barunggam, Bidjara, Bigambul, Budjiti, Euahlayi, Gamilaroi, Githabul, Gunggari, Gwamu (Kooma), Jarowair, Kambuwal, Kunja, Kwiambul, Maljangapa, Mandandanji, Mardigan, Murrawarri, Ngemba, Ngiyampaa, Wailwan and Wakka Wakka Nations.

Ramsar Convention

The Convention on Wetlands of International Importance, an intergovernmental treaty that provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources.

Regulated

A water system in which water is stored and/or flow levels are controlled through the use of structures such as dams and weirs.

Salt interception schemes (SIS)

Large-scale groundwater pumping and drainage projects that intercept saline groundwater flowing into rivers, and dispose of the saline waters by evaporation and aquifer storage at more distant locations.

Surface water

Includes water in a watercourse, lake or wetland, and any water flowing over or lying on the land after having precipitated naturally or risen to the surface naturally from underground (see s. 4 of the Water Act).

The maximum long-term annual average quantities of water that can be taken, on a sustainable basis, from the Basin water resources as a whole, and the water resources, or particular parts of the water resources, of each water resource plan area.

Sustainable diversion limit (SDL)

The maximum long-term annual average quantity of water that can be taken, on a sustainable basis, from the Basin water resources as a whole, and the water resources, or particular parts of the water resources, of each water resource plan area.

Sustainable diversion limit adjustment mechanism (SDLAM)

Basin Plan provision that allows for adjustment of the sustainable diversion limit under certain circumstances.

Take [water]

Removal of water from, or reduction in flow of water into, a water resource.

Water accounting

A systematic process of identifying, recognising, quantifying, reporting and assuring information about water, the rights or other claims to water, and the obligations against water.

Water access licence

Water access licences entitle licence holders:

• to specified shares in the available water within a particular water management area or water source (the share component)
• to take water at specified times, rates or circumstances from specified areas or locations (the extraction component).

Water allocation

The water to which the holder of a water access licence is entitled from time to time under licence, as recorded in the water allocation account for the licence.

Water for the environment

Water used to achieve environmental outcomes, including benefits to ecosystem functions, biodiversity, water quality and water resource health.

Water resource

Of groundwater, water that occurs naturally beneath the ground level (whether in an aquifer or otherwise), or water that has been pumped, diverted or released to an aquifer for the purpose of being stored there. Murray–Darling Basin groundwater resources exclude groundwater in the Great Artesian Basin.

Of surface water, includes water in a watercourse, lake or wetland, and any water flowing over or lying on land after having precipitated naturally or risen to the surface naturally from beneath the ground level.

Water resource plans (WRPs)

Statutory management plans developed for particular surface water and groundwater systems, currently known by different names throughout the Murray– Darling Basin (e.g. ‘water sharing plans’ in New South Wales and ‘water allocation plans’ in South Australia).

Water trading rules

A set of overarching consistent rules enabling market participants to buy, sell and transfer tradeable water rights.

Water year

A continuous 12-month period starting from July, or any other month as prescribed under the water regulation or a resource operations plan, but usually selected to begin and end during a relatively dry season. Used as the basis for processing stream flow and other hydrologic data. The water year period from 1 July to 30 June is used for SDL accounting.