B

acute poison

A toxin that quickly causes a crisis situation to be reached; not chronic

Source: (toolkit 20091023)

Adopted Middle Thread Distance

The distance in kilometres, measured along the middle of a watercourse, from the mouth or junction.

Source: (Stanley, K. 2007)

adsorb

Attach a substance to the surface of a liquid or solid, eg cations to a negatively charged clay or other colloidal material; retain water, ions or exchangeable bases on a colloidal surface.

Source: (toolkit 20091023)

AEP

announced allocation percentage (Qld)

The percentage of the water allocationÃs nominal volume which can be taken during a water year. Applies only to supplemented systems.

Source: (NWC 2007)

annual accounting

The accounting and sharing out of water resources in either a regulated or an unregulated river system on an annual cycle. Some carryover of users accounts from one year to the next, and overdraw of users accounts within a year, may be allowed with time limits on using the carryover or paying back the overdraw in the following year. There may also be annual and multi-year use limits. In a regulated river system the operator manages the water and makes regular announcements on volume that is available for use, and the storage, transmission and operation losses are funded from a communal account.

Source: (Welsh, Podger 2008)

Source: River Systems specification

Annual series

A means of analysing flood frequency that involves selecting the largest values in each year of the record often for the purposes of fitting a frequency distribution. Often the annual maxima are selected on the basis of water years rather than calendar years.

anoxic

Lacking dissolved oxygen; a condition in which oxygen is deficient or absent or exists only in a combined form

Source: (toolkit 20091023)

ANRDL

Australian Natural Resources Data Library

Source: (NWC 2007)

antecedent storage condition

The level of water within a wetland prior to the onset of the next inflow event

Source: (toolkit 20091023)

anthropogenic

Produced or caused by humans

Source: (toolkit 20091023)

applicability and utility

One of EPAâs five Assessment Factors (see definition) that describes the extent to which the information is relevant for the Agencyâs intended use.

Source: (USEPA-CREM)

application niche

The set of conditions under which the use of a model is scientifically defensible. The identification of application niche is a key step during model development. Peer review should include an evaluation of application niche. An explicit statement of application niche helps decision makers to understand the limitations of the scientific basis of the model.

Source: (USEPA-CREM)

application niche uncertainty

Uncertainty as to the appropriateness of a model for use under a specific set of conditions (see application niche).

Source: (USEPA-CREM)

aquifer

Rock or sediment in a formation, group of formations, or part of a formation which is saturated and sufficiently permeable to transmit economic quantities of water to wells and springs.

Source: (ANCID 2001)

Source: (NWC 2007)

aquifer recharge

Build up of the water level in a natural underground storage

Source: (toolkit 20091023)

aquifer storage and recovery

The storage of water through wells installed into aquifers, with subsequent retrieval from the same wells during demand for the stored water

Source: (toolkit 20091023)

area

The extent or measurement of a surface (eg a piece of land or a body of water).

areal actual evapotranspiration

The ET that actually takes place, under the condition of existing water supply, from an area so large that the effects of any upwind boundary transitions are negligible and local variations are integrated to an areal average. For example, this represents the evapotranspiration which would occur over a large area of land under existing (mean) rainfall conditions.

Source: (Chiew 2002)

areal potential evapotranspiration

The ET that would take place, under the condition of unlimited water supply, from an area so large that the effects of any upwind boundary transitions are negligible and local variations are integrated to an areal average. For example, this represents the evapotranspiration which would occur over a very large wetland or large irrigated area, with a never-ending water inflow. A "large" area is defined as an area greater than one square kilometre.

Source: (Chiew 2002)

ARH

Assessment of River Health

Source: (NWC 2007)

A constructed habitat with either static or running water and aquatic or terrestrial vegetation, with the objective of directly reducing contaminants in the water or creating conditions for this to occur.

Source: (toolkit 20091023)

AsciiGrid Pre-processor

A software plugin. A mechanism for rapidly and easily importing daily rainfall or potential evapotranspiration data. It is particularly suitable for large and very large catchments (e.g. 50,000 to a million km2).

Source: (eWater CRC 2010a)

ASDI

Australian Spatial Data Infrastructure

Source: (NWC 2007)

ASIBA

Australian Spatial Information Business Association

Source: (NWC 2007)

asphalt

A hard surface lining formed by the spreading of asphalt on the subgrade of the channel to form a hard surface and seal the channel.

Portion of the National Water Quality Management Strategy (1996) dealing with the physical, chemical and biological components of water for human consumption.

Source: (toolkit 20091023)

Australian Water Balance Model

Australian Water Balance Model. Model available in Source Catchments. A conceptual rainfall runoff model that relates runoff to rainfall with daily data, and calculates losses from rainfall for flood hydrograph modelling. The model contains five stores; three surface stores to simulate partial areas of runoff, a base flow store and a surface runoff routing store.

automated calibration

Process of calibration using an optimisation procedure with model parameter values constrained to physically defensible ranges to find a set of parameter values that minimises a pre-defined objective function. The set of parameter values found may or may not be unique (see âequifinalityâ), may represent the global optimum or merely a local optimum on the response surface of model parameter values, and may or may not be robust and fit for purpose (this is also termed âinverse modellingâ in some domains, e.g. groundwater).

Source: (Madsen et al, 2002)

automatic control

Self-regulating flow control system with sensing and operation initiated via electronic, mechanical or hydraulic means without operator intervention.

Source: (ANCID 2001)

Source: (NWC 2007)

available water

Water potentially available for both extractive and non extractive use.

Advanced Wastewater Treatment Technologies

Source: (NWC 2007)

B

Basin State

(a) New South Wales; (b) Victoria; (c) Queensland; (d) South Australia; (e) the Australian Capital Territory.

Source: (NWC 2007)

Source: Water Act 2007

basin water resources

All water resources within, or beneath the Murray-Darling Basin, but does not include: (a) water resources within, or beneath, the Murray-Darling Basin that are prescribed by the regulations for the purposes of this paragraph; or (b) groundwater that forms part of the Great Artesian Basin.

Source: (NWC 2007)

Source: Water Act 2007

BASIX

Building Sustainability Index

Source: (NWC 2007)

bathymetry

The topography or the shape of the land below the water surface.

Source: (toolkit 20091023)

bentonite sediment sealant

Dry, high swell bentonite in granular form is spread over the channel water surface. This material sinks to form a seal at the base of the channel.

Source: (ANCID 2001)

Source: (NWC 2007)

bentonite soil blanket

A liner constructed by uniformly spreading powdered bentonite over the surface area of a dry channel. The powder is then mixed into the top layer of soil using a rotary type mixer and to 100 mm thick blanket over the channel section.

Biological treatment involves the addition of biological agents to either the channel water or soil layer, which assist in reducing the seepage from the channel. There is also the potential for additional ecological benefits in using biological treatments.

Source: (ANCID 2001)

Source: (NWC 2007)

biologically activated carbon

A form of carbon with high porosity and surface area used in water treatment to adsorb pollutants, to allow their biological degradation.

Source: (toolkit 20091023)

bioreactor

A vessel or tank in which bacteria are used to decompose the organic matter content of wastewater.

Source: (toolkit 20091023)

biosolids

The stabilised organic solids derived from sewage treatment processes.

Source: (NWC 2007)

biosolids reuse

Reuse involves managing biosolids safely and sustainably to beneficially utilise their nutrient, energy, or other values. This may include biosolids beneficially used for agriculture (eg fertiliser), soil conditioning,mine rehabilitation, and other applications recognised as reuse.

bore

A deep hole of small diameter bored to the aquifer of an artesian basin, through which water rises under hydrostatic pressure.

buffer zone

The area between the basin and its interception works and the surrounding land. Often contains trees or other vegetation to improve the aesthetics of the basin.

Source: (toolkit 20091023)

buffering

Resisting a change in pH when acids or bases are added to a solution

Source: (toolkit 20091023)

Baseline Water Resource Assessment

Source: (NWC 2007)

C

CAEDYM

Computational Aquatic Ecosystem Dynamics Model

Source: (toolkit 20091023)

calculated

An value or number determined mathematically or via measurement.

Calendar year

Year starting on 1 January and ending on 31 December.

calibration

Process of adjusting the values of model parameters within physically defensible ranges until the model performance adequately matches observed historical data from one or more locations represented by the model (i.e. a match is obtained that is robust and fit for purpose).

Source: (USEPA-CREM)

calibration model

A calibration model involves the modelling of flows, extractions, operational rules, and infrastructure that occurred historically to produce a model that can be used to simulate âwhat if scenariosâ based on historical flow, rainfall and evaporation patterns and catchment conditions.

Source: (Stanley, K. 2007)

canal

The expression âCanalâ is also used for some main channels and usually forms part of the proper name in these cases, eg Cattanach Canal, Mulwala Canal.

Use: channel

Source: (ANCID 2001)

Source: (NWC 2007)

cap

An upper limit for the volume of water available for use from a waterway, catchment, basin or aquifer.

Source: (NWC 2007)

cap development conditions

This is a scenario that represents water resource development infrastructure and management practices that existed in the 1993/94 water year (as defined in the MDBMC Cap). This term is relevant to hydrologic modelling for water management purposes, Water Sharing Plans and Cap accountability.

Source: (Welsh, Podger 2008)

capillary fringe

The zone immediately above the watertable, where water is drawn upwards by capillary tension.

Source: (ANCID 2001)

Source: (NWC 2007)

capillary tension

The forces acting on soil moisture in the unsaturated zone, attributable to surface tension effects and pore geometry.

Source: (ANCID 2001)

Source: (NWC 2007)

capital works grants

cease to pump indicator

The indicator measurement at which irrigators must stop pumping.

Source: (Welsh, Podger 2008)

ceding

Ceding occurs when there are multiple water owners with fixed storage shares and one water owner gives up water to another water owner using predefined percent distribution rules.

Source: (Gilmore et al 2008)

Celerity

The velocity of a very small wave along a body of water.

change (NSW)

Change to the location, category, water source of a licence.

Source: (NWC 2007)

Manning's n is an estimate of channel roughness, used in the calculation of flow velocity and discharge. The value of n is typically between 0.01 and 0.1 and varies with channel slope, bed material composition (sand, gravel, cobble etc), in-stream vegetation and sinuosity.

Source: (Ward and Trimble 2004)

channel seepage

Loss of water from a channel via infiltration through micro-pores and soil processes (ie not via preferential flow through macropores). Seepage as measured in pondage tests includes a leakage component. Generally the term channel seepage refers to both seeped and leaked water, as the two are not easily separated.

Source: (ANCID 2001)

Source: (NWC 2007)

Channelisation

Process that occurs when defined streams start to form to capture water that had previously flowed from an upstream hillslope along undefined flow pathways.

check regulator

Commonwealth Environmental Water Holder

The Commonwealth Environmental Holder established under section 104.

Source: (NWC 2007)

Source: Water Act 2007

Commonwealth environmental water holdings

has the meaning given by section 108.

Source: (NWC 2007)

Source: Water Act 2007

community basins

Local-scale basins that are shared by a small group of properties and are either privately or authority owned.

Source: (toolkit 20091023)

community service obligation

The amount received or receivable from governments for specific agreed services to the community. A CSO must be: - a non-commercial product or service, that is, products and services whose provision is not in the commercial interests of a commercial business entity; - clearly purchased by the Government for delivery to the community on its behalf to achieve a specific social or economic objective that has been established by the Government; and - purchased by the government from an appropriate commercial business entity.

Source: (NWC 2007)

compacted clay

Compacted clay or a compacted earth lining consists of importing (and compacting) soils which have better soil characteristics than the in-situ soils (ie low permeability and high resistance to erosion).

Source: (ANCID 2001)

Source: (NWC 2007)

compaction of soils in-situ

This involves the enhancement of in-situ soil characteristics such as stability and permeability using standard compaction techniques.

Source: (ANCID 2001)

Source: (NWC 2007)

component

A collective term for nodes, links, rainfall runoff models, filters and constituent generation models.

component model

A model associated with a particular component e.g. node models are associated with nodes; link models with links etc.

conceptual basis

This is the underlying scientific foundation of model algorithms or governing equations. The conceptual basis for a model is either empirical (based on statistical relationships between observations) or mechanistic (process-based) or a combination. See definitions for: empirical model and mechanistic model.

Source: (USEPA-CREM)

conceptual model

A hypothesis regarding the important factors that govern the behaviour of an object or process of interest. This can be an interpretation or working description of the characteristics and dynamics of a physical system.

Source: (USEPA-CREM)

conceptual rainfall runoff model

A model that represents the hydrological response as a series of mathematical relationships, often attempting to represent the storage and transport of water through conceptual soil water and groundwater storage buckets.

concrete

A hard surface lining formed by the construction of concrete channel sections either in-situ or elsewhere, which are placed onto tof the channel subgrade to form a hard surface and seal the channel.

Source: (ANCID 2001)

Source: (NWC 2007)

constituent phase

The ninth phase of execution within a time-step. In this phase the transport and transformation of water quality constituents is undertaken.

Source: (Podger 2011)

constraint phase

The second phase of execution within a time-step. In this phase relevant constraints are identified.

Source: (Podger 2011)

Biological or chemical substance or entity, not normally present in a system, capable of producing an adverse effect in a biological system, injuring structure or function.

Source: (toolkit 20091023)

Continuity equation

An equation that expresses equilibrium between the various flow components (e.g. inflow, outflow, and storage). Derived initially by Leonardo da Vinci as a statement of the law of conservation of mass.

Source: (Ward and Robinson 1990)

continuous accounting

1. The sub-division of water resources in a dam (within a regulated river system) into user shares. The shares are updated on a frequent basis: eg currently monthly in the Gwydir and Namoi systems. Users manage their usage from their own account. 2. A resource assessment and allocation system with carryover only limited by available storage, user's balances limited to an upper bound, and the storage, transmission and operation losses funded from a communal account. 3. The accounting and sharing out of water resources in either a regulated or an unregulated river system based on an annual cycle, as for annual accounting, but with broader carryover provisions than under annual accounting. This provides water users with greater flexibility in managing their own accounts than under annual accounting, although account balances may not be permitted to become negative (ie no overdraw permitted; if a user needs more water they can enter into a temporary or permanent trade to buy the water needed). Carryover may be limited by annual and multi-year use limits. In a regulated river system the storage, transmission and operation losses are funded from a communal account.

Source: (Welsh, Podger 2008)

Source: River Systems specification

Source: (Ribbons, C 2011)

continuous sharing method

A resource assessment and allocation system with unlimited carryover, user's balances limited to an upper bound, storage losses funded by the water users in proportion to their storage volumes, transmission and operation losses funded by users based on their storage factors. Variation in operation from the fixed storage factors is funded by a joint accounting reconciliation.

Source: River Systems specification

Covenants requiring that the Water Access Entitlement to be used or not used in specified ways.

Source: (NWC 2007)

covered flexible membrane

The construction of a lined channel using a geomembrane to reduce seepage where the geomembrane is covered with a nonerosivematerial that protects the geomembrane.

Source: (ANCID 2001)

Source: (NWC 2007)

credibility

The confidence that (potential) users have in a model and in the information derived from the model such that they are willing to use the model and the derived information. Specifically, credibility is a function of the performance record of a model and its conformance to best available, practicable science.

Source: (Morton 1993)

critical drought

The duration in time that resulted in the either the lowest dam levels, aquifer levels or pressures, or longest duration of restricted water access.

Source: (Welsh, Podger 2008)

crop efficiency factor

The dimensionless coefficient, crop factor, assumes 100% efficiency of evapotranspiration from the crop. In reality, there is not 100% efficiency so the crop efficiency factor adjusts for this. Sometimes, this is used as a calibration factor when calibrating a crop model to recorded water use.

crop factor

Dimensionless coefficient used to calculate evapotranspiration requirement for a particular crop from the potential evapotranspiration for a reference crop (ETo). Crop factors are determined experimentally and take into account leaf area development of the crop and the crop canopy physiology.

Source: (ANCID 2001)

Source: (NWC 2007)

Crop Water Economic Index

Gross Production ($) Ã· Evapotranspiration (mm)

Source: (NWC 2007)

Source: (ANCID 2001)

Crop Water Production Index

Total Product (kg) Ã· Evapotranspiration (mm)

Source: (NWC 2007)

Source: (ANCID 2001)

crop water requirement

The total volume of water required to meet the plants requirements for evapotranspiration for a given planting area and period (excluding leaching fraction).

Source: (ANCID 2001)

Source: (NWC 2007)

cropping farming

Farm type for which main crops are winter and/or summer grain (wheat, barley, oat etc.).

Source: (toolkit 20091023)

cross banks

mounds of soil created by scraping of snig tracks

Source: (toolkit 20091023)

culvert

An underground structure or pipe carrying water beneath a road, carriageway etc.

Source: (ANCID 2001)

Source: (NWC 2007)

current balance of committed water

Volume of water committed (set aside) in storages for environmental water rules at a point in time.

Source: (NWC 2007)

current development conditions

Use: water storage

Source: Macquarie Dictionary

Source: (NWC 2007)

dam permit (Tas)

Approval under Part 8 of the Water Management Act 1999 to undertake dam works (NB: a dam permit does not take effect until a water licence to take water is obtained).

Source: (NWC 2007)

dam safety emergency plan

A continually updated set of instructions and maps that deal with possible emergency situations or unusual occurrences at a major dam.

Source: (Welsh, Podger 2008)

data assimilation

The combining of diverse data, possibly sampled at different times and intervals and different locations, into a unified and consistent description of a physical system, such as the state of the atmosphere.

Source: (AMS Glossary, 2010)

Data calculator

(software plugin) A plugin that allows the user to perform a range of simple transformation functions on single values, a time-series of values or rasters of spatial data.

data fusion

The use of techniques that combine data from multiple sources and gather that information in order to achieve inferences, which will be more efficient and potentially more accurate than if they were achieved by means of a single source. (Source: Wikipedia, http://en.wikipedia.org/wiki/Data_fusion, accessed on 2 Nov. 2010.)

Data modification Tool

(software plug-in) Provides a basic set of operations for modifying input data, such as a raster of land use, based upon an approach that builds rules from combination of various conditions.

Source: (eWater CRC 2010b)

data uncertainty

Uncertainty (see definition) that is caused by measurement errors, analytical imprecision and limited sample sizes during the collection and treatment of data. Data uncertainty, in contrast to variability (see definition) is the component of total uncertainty that is âreducibleâ through further study.

Source: (USEPA-CREM)

DDEMS

Dam Development Effect and Management Statement (Tas)

Source: (NWC 2007)

dead storage

Capacity of a storage that is below the minimum operating level and cannot under normal circumstances be supplied to customers. Dead storage can be accessed for emergency supply (ie in times of drought) by installing temporary pumps to get the water out from below the minimum operating level. The minimum operating level can also be determined by water quality constraints.

DEM

Digital Elevation Model

Use: digital elevation model

Source: (NWC 2007)

Source: (toolkit 20091023)

demand

A requirement for water to be met from the sources in the river system. Demands may be consumptive or non-consumptive and may, for example, include town water supplies, irrigation, hydro, industrial, minimum flows, environmental and recreational requirements, and interbasin transfers, but need not be limited to these.

The time it takes for a âparcelâ of water to flow from the inlet of a wetland system to the outlet. Depending on the flow path taken by individual parcels of water, the time may vary significantly within the one system

Source: (toolkit 20091023)

deterministic model

Deterministic models contain no random component, and provide no measure of error or uncertainty. They are commonly used for descriptive, analytical and predictive purposes, for example comparison of discharge in paired catchments. Contrast with stochastic models. A model that provides a solution for the state variables rather than a set of probabilistic outcomes. Because this type of model does not explicitly simulate the effects of data uncertainty or variability, changes in model outputs are solely due to changes in model components or in the boundary conditions or initial conditions.

Source: (Black 1996)

Source: (USEPA-CREM)

dethridge meter outlet

Positive displacement flow measurement device used to determine water volumes supplied from the authority supply channel to an individual farm. The meter consists of a metal wheel fitted with 8 vanes around the circumference and mounted on a horizontal axis in a concrete flume emplacement. Water flowing along the flume causes the wheel to rotate and a counting device records the number of revolutions which provides a direct measure of the volume of water supplied over a given time. The counting mechanism records the volume in ML passing through the meter over a given time from which flow rate in ML/d may be derived. In field use the rate of rotation of the wheel in âRevolutions per minuteâ, (usually abbreviated to âRevsâ) is used to determine the approximate flow rate by application of a conversion factor determined by the size and geometry of the particular meter.

Source: (ANCID 2001)

Source: (NWC 2007)

dethridge-long meter

The Dethridge-Long (DL) Meter is an improved high capacity meter with 6 vanes and accurately measures flows up to 20 ML/d. The Dethridge Meter is intended primarily for measurement in open channel systems but can also be adapted for use in low pressure pipe systems, channel outfalls and drainage systems.

Source: (ANCID 2001)

Source: (NWC 2007)

developed area

The maximum land area that a farmer has the infrastructure in place to irrigate.

Source: (Welsh, Podger 2008)

developed yield

Developed yield should be reported as the total volume of water that could be diverted for use, on average, at existing infrastructure levels over the critical period of interest and at a set level of reliability. The developed yield does not include volumes released for the environment, that is, it is the yield capable of being supplied under current infrastructure development after provisions for environmental flows have been made. For some surface water management areas the developed yield may exceed the sustainable yield.

Source: (NWC 2007)

dewatering

Removal of water from sludge, usually following addition of a polyelectrolyte, using a filter press.

Source: (toolkit 20091023)

DHG

Discharge hillslope gradient

Source: (toolkit 20091023)

A stage in sewage treatment whereby air is bubbled through alum and polyelectrolyte-treated\ water to collect the floc so that it forms a scum on the surface which overflows into a trough for removal.

Source: (toolkit 20091023)

Dissolved oxygen

Oxygen that is dissolved in solution in water.

distillation

Conversion of a substance to vapour by heating, then condensing the volatile material by cooling in a retort or still; recovery and/or removal of volatile substances by heating and condensation.

Source: (toolkit 20091023)

distributed water

Water supplied by water authorities (metropolitan and non-metropolitan) via a distribution network.

A rural water service that provides for the diversion of raw water by customers from a surface water source at a specified level of service and which confers common obligations on customers. Typically, service provision involves water access, works or site licence administration, metering or measurement and monitoring of diversions on a regular basis. Aspects of water planning and water resource management may also be involved.

Source: (NWC 2007)

Source: (National Performance Framework 2006-07)

drainage system

An engineered network of horizontal pipe drains (also referred to as tile drains), horizontal open drains, or groundwater pumping from bores (also called tubewells, spearpoints or wells) used to manage water tables and thereby control waterlogging and the build up of salt in the plant root zone.

Source: (toolkit 20091023)

drainage water

Water that passes beyond the root zone as a result of rainfall and irrigation.

Source: (toolkit 20091023)

drawdown

The lowering of a storage resulting from the loss of water from the storage.

Source: (Stanley, K. 2007)

drop structure

Concrete, timber or steel weir structure placed in supply channel or drain to dissipate energy (to minimise erosion) at a point of desired reduction in water level.

Source: (ANCID 2001)

Source: (NWC 2007)

Dry weather concentration (mg/L)

Concentration of a given constituent during periods of baseflow only.

dS

deciseimens

Source: (NWC 2007)

dual reticulation

A system of piped water reticulation in which treated effluent is provided for industrial, household or garden use, via a separate delivery system to that for potable use.

Source: (toolkit 20091023)

DWC

Dry Weather Concentration

Source: (toolkit 20091023)

DWC (mg/L)

Concentration of a given constituent during periods of Baseflow only.

Use: Dry weather concentration (mg/L)

dynamic model

A model providing the time-varying behaviour of the state variables.

Source: (USEPA-CREM)

DYRESM

Dynamic Reservoir Simulation Model

A dynamic complex of plant, animal and micro-organism communities and their non-living environment interacting as a functional unit. A regime involving the interactions between living organisms and their environment; a biotic community of organisms and their relationships with the physical, chemical and biological components of their environment.

Source: (EPA 1999)

Source: (NWC 2007)

Source: (toolkit 20091023)

ecosystem (WA)

A term used for a specific environment, eg wetland, or part thereof, to include all the biological, chemical and physical resources and the interrelationships and dependencies that occur between those resources.

Source: (NWC 2007)

EDC

Endocrine disrupting chemicals

Source: (NWC 2007)

effective rainfall

That portion of total precipitation that is available for uptake by plants.

EMC

Event Mean Concentration

Source: (toolkit 20091023)

EMC (mg/L)

Mean concentration of a particular constituent over the quick flow component of an event hydrograph. EMC = Total constituent load during the event / Total quick flow during the event.

Use: Event mean concentration (mg/L)

EMC/DWC

Model available in Source Catchments. The Event Mean Concentration (EMC) / Dry Weather Concentration (DWC) model applies two fixed constituent concentrations (EMC & DWC) to a functional unit (FU) to calculate total constituent load. This model is based on physical principles.

Use: Event Mean Concentration/Dry Weather Concentration

Source: (eWater CRC 2010a)

empirical model

An empirical model is one where the structure is determined by the observed relationship among experimental data. These models can be used to develop relationships that are useful for forecasting and describing trends in behaviour but they are not necessarily mechanistically relevant.

Source: (USEPA-CREM)

EMS

Environmental Management System

Source: (NWC 2007)

EMSS

Environmental Management Support System

Source: (toolkit 20091023)

EMSS Pre-Processing Tools

(software plugin) Offers a range of tools that were available with the EMSS modelling framework, the fore-runner of Source Catchments. Tools include Hazard Map Scaling, EMSS Sediment Export Coverage Tool and Bulk Clip Time Series.

Source: (eWater CRC 2010b)

encumbrances (WA)

A lodged or registered interest in water, by a person who is not the registered proprietor. Examples are mortgages, lease agreements, caveats and easements.

Source: (NWC 2007)

end-of-system flow

Streamflow at the end of a defined river system; eg Murrumbidgee River at Balranald.

Source: (Welsh, Podger 2008)

Enrichment

Enrichment of solute concentrations in runoff occurs due to differential attachment of solutes on to finer particles (silt and clay) and these finer particle being transported larger distances as they stay suspended for longer in the runoff.

en-route storage

A water storage (weir or lake) located either instream or off-stream in the middle or lower part of a river system (eg Hay Weir on the Murrumbidgee).

Source: (Welsh, Podger 2008)

ENSO

El Nino Southern Oscillation

A specific instance of a water user node where the water demands of an environmental asset are estimated based on previously agreed rules to protect environmental values.

environmental flow

The provision of water within wetlands, rivers and groundwater systems to maintain aquatic ecosystems and their benefits where the ecosystem is subject to competing water uses, eg irrigation.

Source: (Welsh, Podger 2008)

environmental flow objective (Qld)

An environmental flow objective-as specified in a water resource plan (WRP)-is a flow objective relating to the health of natural ecosystems for the achievement of ecological outcomes. For example, the WRP could specify that the mean annual stream flow at a particular point must be maintained at or above 75% of the mean annual flow that would occur in the absence of all development.

Source: (NWC 2007)

environmental manager

An expertise based function with clearly identified responsibility for the management of environmental water so as to give effect to the environmental objectives of statutory water plans - the institutional form of the environmental manager will vary from place to place reflecting the scale at which the environmental objectives are set and the degree of active management of environmental water required - the environmental manager may be a separate body or an existing Basin, catchment or river manager provided that the function is assigned the necessary powers and resources, potential conflicts of interest are minimised, and lines of accountability are clear.

Source: (NWC 2007)

Source: National Water Initiative

The water regimes that are provided as a result of the water allocation decision making process taking into account ecological, social and economic impacts. They may meet in part or in full the ecological water requirements.

Source: (NWC 2007)

environmental water requirements

Descriptions of flow regimes (eg volume, timing, seasonality, duration) that are needed to sustain the ecological values of aquatic ecosystems, including their processes and biological diversity, and that aredesigned to provide environmental outcomes.

Source: (NWC 2007)

environmentally sustainable level of extraction

The level of water extraction from a particular system which, if exceeded would compromise key environmental assets, or ecosystem functions and the productive base of the resource.

Source: Macquarie Dictionary

Source: (NWC 2007)

ETO

Potential or actual evapotranspiration. Process of moisture loss to the atmosphere from plants by transpiration and evaporation.

Use: evapotranspiration

evaluation

The process used to generate information to determine whether a model and its results are of a quality sufficient to serve as the basis for a regulatory decision.

Source: (USEPA-CREM)

evaluation and review

One of EPAâs five Assessment Factors (see definition) that describes the extent of independent verification, validation and peer review of the information or of the procedures, measures, methods or models.

Source: (USEPA-CREM)

evapoconcentration

The increase in salinity of water in the basin as it evaporates. A non-linear decrease in evaporation rate is observed as the water salinity increases

Source: (toolkit 20091023)

evaporate

To turn to vapour; pass off in vapour, or to give off moisture.

Source: Macquarie Dictionary

Source: (NWC 2007)

Mean concentration of a particular constituent over the quick flow component of an event hydrograph. EMC = Total constituent load during the event / Total quick flow during the event.

Event Mean Concentration/Dry Weather Concentration

Model available in Source Catchments. The Event Mean Concentration (EMC) / Dry Weather Concentration (DWC) model applies two fixed constituent concentrations (EMC & DWC) to flow generated from a functional unit (FU) to calculate total constituent load. EMC is applied to quick flow and DWC to baseflow.

Source: (eWater CRC 2010a)

Source: (Merritt, Letcher, Jakeman 2003)

a systematic process for quantifying, typically in probabilistic terms, expert judgments about uncertain quantities. Expert elicitation may be used to characterise uncertainty and fill data gaps where traditional scientific research is not feasible or data are not yet available. Typically, the necessary quantities are obtained through structured interviews and/or questionnaires. Procedural steps can be used to minimise the effects of heuristics and bias in expert judgments.

Source: (USEPA-CREM)

Exponential decay

A model of the reduction in the load of a constituent with time where the rate of reduction is proportional to the load of the constituent at that point in time.

Export rate (kg/ha/a)

Average rate of generation and/or delivery to stream of a particular constituent per unit area and per unit time.

Export Rate model

Model available in Source Catchments. The Export Rate model applies a fixed constituent rate to a functional unit (FU) to calculate total constituent load. It requires only single parameter so is quick to use and therefore useful for exploring sensitivity. This model is based on physical principles.

Source: (eWater CRC 2010a)

exposed flexible membrane

An uncovered or exposed geomembrane lined channel is constructed by simply placing the material on the subgrade of the channel.

Source: (ANCID 2001)

Source: (NWC 2007)

extraction for environmental purposes

Extraction of water pursuant to an environmental water access entitlement.

Source: (NWC 2007)

extraction rate

The rate in terms of unit volume per unit time that water can be drawn from a surface or groundwater system. Used in the NWI in the context of a constraint that might exist due to the impact of exceeding a particular extraction rate at a particular point or within a specified system.

The equilibrium water content of an undisturbed soil core at a soil suction of 0.01MPa. If only loose, or disturbed soil is available, the equilibrium water content at 0.033MPa suction should be used. In both cases the method used to determine the field capacity value should be clearly stated (Loveday, 1974).

Source: (ANCID 2001)

Source: (NWC 2007)

field water requirement

Total volume of water required to meet the combined water requirements for evapotranspiration, leaching and distribution for a given planting area and period.

Source: (ANCID 2001)

Source: (NWC 2007)

filter

A filter model represents any transformation or storage of constituents that takes place between when they are generated and when they reach a sub-catchment node. Filtering allows representation of physical processes that may occur due to riparian buffers, small dams or detention ponds or denitrification processes.

filter model

A model that represents the reduction in concentration of a particular constituent between where it is generated in a catchment and delivery of that constituent to the node-link network in a Source Catchments model.

filter-strips

intact belts of forest adjacent to streams to control water quality

Source: (toolkit 20091023)

filtration

The separation of suspended material from a liquid by passing the liquid through a porous substance, a filter or other membrane which will retain insoluble matter or particles large in size than the pores in the membrane.

Source: (toolkit 20091023)

Financial year

Year that aligns with Government, company or tax reporting requirements. In Australia, taxation requirements and many companies and Governments use 1 July through 30 June as the financial year and this year is often adopted as the reporting year for water accounts.

Fine sediment

Sediment that is trapped principally by infiltration and adhesion.

Source: (eWater CRC 2008)

first flush

The initial flow of stormwater runoff that often contains high concentrations of contaminants that have built up during intervening dry periods; a mechanical device used to reject and discard the initial runoff from a roof catchment, so as to reduce contaminant loading to a storage tank.

Source: (toolkit 20091023)

fish ladder

A structure on a dam or weir designed to allow fish to move upstream to fresh water or downstream to the estuary or sea

Source: (toolkit 20091023)

fixed charge

The fixed amount the business levies on a residential property per year. This is the component of each residential propertyâs bill that varies with the amount of water used or sewage produced.

Source: (NWC 2007)

Fixed Concentration

Node model available in Source Catchments. The fixed concentration node model allows the user to specify the concentration of a constituent at a particular node. This is a conceptual model.

Source: (eWater CRC 2010a)

fixed crest weir

Permanent weir structure across a channel waterway used to measure water flow and/or control upstream water level. This may include both sharp crested and broad crested weirs.

Source: (ANCID 2001)

Source: (NWC 2007)

flexible membrane

A geomembrane is a thin flexible impermeable liner, which combined with the strength of the base soil, can be used to reduce seepage. There are two distinct ways of constructing channels using geomembranes: Covered flexible membrane and exposed flexible membrane.

Source: (ANCID 2001)

Source: (NWC 2007)

flood flows

Excess water from an on-stream reservoir passing through a spillway to re-enter the waterway

Source: (toolkit 20091023)

Flood frequency curve

A curve that shows the mathematical relationship between flood peak flows, flood peak water levels or flood volumes at a particular location and the annual exceedance probability of that quantity.

Flood Harvesting Diversion

A node model available as a plugin to Source Catchments. The Flood Harvesting Diversion model replicates a licensing procedure to grant a landholder (such as a farmer or irrigator) permission to divert an amount of water from the river system if the water level exceeds a height threshold, such as during a major flood.

Source: (eWater CRC 2010a)

Flood hydrograph

The trace which describes the change in stream flow (or water level) over time at a given location in a stream during a flood event.

flood mitigation

Reduction of the severity of physical and economic losses caused by floodwater inundating land or damaging structures

Source: (toolkit 20091023)

flood mitigation volume

A volume of storage that is managed to minimise the risks of downstream flooding and may vary throughout the year.

Source: (NWC 2007)

Flood peak

The maximum value of flow or water level observed during a flood event.

flood retarding basin

A temporary flood storage system used to reduce flood peaks.

Source: (toolkit 20091023)

flooding frequency

the percentage of days (during December-April) during which flooding occurred in the Barmah-Millewa Forest (also âunseasonal flooding frequencyâ).

Source: (toolkit 20091023)

floodplain

The low-lying land adjacent to the riparian zone.

Source: (toolkit 20091023)

floodplain harvesting

Includes water: Pumped from the floodplain to an on farm storage during large floods using secondary lift pumps. Entering an on farm storage from the floodplain because flood levels are high enough to allow it to flow in by gravity.

Source: (Welsh, Podger 2008)

Flow

Rate of movement of water past a point per unit time.

flow distribution phase

The sixth phase of execution within a time-step. During the flow distribution phase, Source determines the physical constraints on releases, and if necessary adjusts the releases within the bounds of these constraints. The flow of water is then modelled from the most upstream node, down through the system. As the model passes demands, water is extracted to meet these demands if there is sufficient water available to meet the previous order and the current requirement. The order of execution is determined in the network phase.

Source: eWater CRC

Source: (Podger 2011)

Source: (Holz, 2010)

flow duration curve

A graphical representation of a ranking of all the flows in a given period, from the lowest to the highest, where the rank is the percentage of time the flow value is equalled or exceeded. These curves may be derived for flows in any time interval, such as daily flows, monthly flows or annual flows.

Source: (Welsh, Podger 2008)

flow percentile

The percentage of time for which a given flow is equalled or exceeded. The flow percentiles are used to define a flow duration curve.

Source: (Welsh, Podger 2008)

flow routing

The change in magnitude, speed and shape (height and duration) of a flow hydrograph as it moves downstream, due to channel and floodplain storage and frictional effects. Also known as flow attenuation and translation.

Source: (Welsh, Podger 2008)

flow routing model

A model for estimating the flow hydrograph at the downstream end of a model link (or stream reach) given the flow hydrograph at the upstream end of the model link or stream reach.

flume

Open conduit having concrete, metal or timber sides and floor used as a supply channel where topography is not suitable for a conventional earthen channel. Flumes are often raised above natural surface and supported by columns or piers.

Source: (ANCID 2001)

Source: (NWC 2007)

Flux

Rate of water flow or flow of a constituent past a point per unit time.

FMA

Forest Management Area

Source: (toolkit 20091023)

forcing/driving variables

External or exogenous (from outside the model framework) factors that influence the state variables calculated within the model. These may include, for example, climatic or environmental conditions (temperature, wind flow, oceanic circulation, etc.).

Source: (USEPA-CREM)

forms

Models can be represented and solved in different forms, including: analytic, stochastic, and simulation.

Source: (USEPA-CREM)

freeboard

Vertical distance between a channelâs maximum design operating level and the top of the channel bank.

Source: (ANCID 2001)

Source: (NWC 2007)

freehold land (WA)

The greatest estate that can be held by a person without being the absolute owner, which is the Crown.

Source: (NWC 2007)

FU

Functional Unit. Areas of a catchment (either contiguous or non-contiguous) that are assumed to have similar responses in terms of hydrology and/or generation and movement of constituents.

Use: functional unit

full supply level

The maximum normal operating level of a reservoir behind a dam. The water level can go above this, such as during floods when the spillway is operating (referred to as flood surcharge), but if the water level rises above the crest of the dam then the dam will be overtopped, and it may fail. For example, Burrinjuck Dam was overtopped on one occasion, but did not fail. Sometimes the FSL may be set lower than the maximum capacity for dam safety reasons.

Source: (Welsh, Podger 2008)

1,000,000,000 litres.

Source: (NWC 2007)

GIS

Geographic Information System Geographical Information System

A raw water supply service from a supply network which is provided as an open gravity outfall to a customerâs property or, if a piped supply network, where the design residual pressure head at more than 95% per cent of customer service points is less than 3 metres.

Source: (NWC 2007)

(a) water occurring naturally below ground level (whether in an aquifer or otherwise); or (b) water occurring at a place below ground that has been pumped, diverted or released to that place for the purpose of being stored there; but does not include water held in underground tanks, pipes or other works.

Source: Water Act 2007

Source: (NWC 2007)

Groundwater - Surface Water Interaction Tool

Groundwater - Surface Water Interaction Tool developed by eWaterCRC.

Source: (anonymous 2009)

groundwater dependent ecosystems

Ecosystems that are dependent on groundwater for their existence and health.

Source: (NWC 2007)

groundwater discharge

Flow of groundwater from the saturated zone to the earth surface.

Source: (NWC 2007)

groundwater diversion service

A rural water service which enables customers to divert or pump water from a groundwater source at a specified level of service and which confers common obligations on customers. Typically, service provision involves water access, works or site licence administration, metering or measurement and monitoring of diversions on a regular basis. Aspects of water planning and water resource management may also be involved.

Source: (NWC 2007)

Source: (National Performance Framework 2006-07)

groundwater drawdown

The lowering of the water table resulting from the loss of water from the aquifer.

Source: (Stanley, K. 2007)

groundwater flux

Water lost or gained from the interaction between the river and a groundwater acquifer. A loss is represented by a positive number, a gain by a negative number.

Source: River Systems specification

groundwater management unit

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.

The source and upper reaches of a natural waterway.

Source: (Stanley, K. 2007)

headwater storage

A water storage reservoir created by a dam in the upper (usually higher rainfall) part of a river valley.

Source: (Welsh, Podger 2008)

hectare

An area equal to the area of an equilateral rectangle where each side is one hundred metres in length.

Source: eWater CRC

heritage value

The heritage value of a place includes the placeâs natural and cultural environment having aesthetic, historic, scientific or social significance, or other significance, for current and future generations of Australians.

Source: (EPA 1999)

Source: (NWC 2007)

high flow loss

Water loss from a reach during periods of high flow.

Source: River Systems specification

high level of development

hydro-electric

Relating to the generation and distribution of electric energy derived from the energy of falling water or other hydraulic source.

Source: Macquarie Dictionary

Source: (NWC 2007)

hydrograph

The trace which describes the change in stream flow (or water level) over time at a given location in a river system.

Source: (Welsh, Podger 2008)

hydrologic cycle

The circulation of water from the oceans through the atmosphere to the land and ultimately back to the ocean.

Source: (Welsh, Podger 2008)

hydrologic effectiveness

Describes the interaction between runoff capture, detention time and detention volume within a wetland system.

Source: (toolkit 20091023)

Hydrologic equation

"An equation that expresses equilibrium between the various flow components (e.g. inflow, outflow, and storage). Derived initially by Leonardo da Vinci as a statement of the law of conservation of mass."

Use: Continuity equation

Source: (Ward and Robinson 1990)

hydrologic model

A hydrologic model is a computer program that simulates stream flows, water losses, storages, releases, in-stream infrastructure, water diversion and water management rules within a river system.

Source: (Stanley, K. 2007)

hydrologic regime

Describes the long-term spatial variation in the water depths and period of inundation within a wetland system.

Source: (toolkit 20091023)

hydrological forecasting

WMO (2009) lists three categories:a) Short term: periods of up to two daysb) Medium range: periods ranging from 2 to 10 daysc) Long range: periods exceeding 10 days

Source: (WMO 2009)

hydrological response unit

Similar to a functional unit, but can be a more specific term that only relates to hydrological response rather than generation and delivery of constituents.

Use: functional unit

hydrology

The science dealing with water on the land, or under the earthâs surface, its properties, laws, geographical distribution, etc. The science of the natural occurrence, distribution and movement of water. The study of water occurrence.

Source: Macquarie Dictionary

Source: (NWC 2007)

Source: (toolkit 20091023)

hydrotropic

Turning or tending towards moisture.

Instream Flow Incremental Methodology

Source: (NWC 2007)

in situ field capacity

The percentage of water remaining in a soil two or three days after having been saturated, with the soil surface covered to prevent evapotranspiration and after free drainage has practically ceased.

Source: (ANCID 2001)

Source: (NWC 2007)

indigenous heritage value

Indigenous heritage value of a place means a heritage value of the place that is of significance to indigenous persons in accordance with their practices, observances, customs, traditions, beliefs or history.

Source: (NWC 2007)

Source: (EPA 1999)

infiltration

The process by which water soaks into the soil from precipitation or irrigation. The movement of water through soil pores or other porous material

Source: (Welsh, Podger 2008)

Source: (toolkit 20091023)

Infiltration capacity

Maximum rate per unit time and area that water (usually from precipitation) can pass into an unsaturated soil. Usually this is the same as the hydraulic conductivity of the soil.

Infiltration excess runoff

Runoff that is generated due to the rate of water input (usually from precipitation) exceeding the infiltration capacity of the catchment.

infiltration limited

Describes basins where the rate of leakage is determined by factors that impact at the base of the basin. Leakage is therefore determined by the depth of water in the basin, and is moderated by the permeability of the basin floor.

Source: (toolkit 20091023)

inflow

The average flow rate into a link or river reach during a time-step.

Source: River Systems specification

inflow (stormwater)

Stormwater entering a sewage treatment plant, due to illegal connections. Movement of liquid into a storage.

Source: (toolkit 20091023)

inflow node

A node model available in Source. An Inflow node originates flows into a model. Inflows include runoff generated for defined headwater and residual catchment areas in the river system, point sources of water such as inter-basin transfers, and return flows from water users. Inflows are not used to account for rain falling directly on water bodies.

inflows

Surface water runoff and deep drainage to groundwater (groundwater recharge) and transfers into the water system (both sufrace and groundwater), for a defined area.

Source: (NWC 2007)

influent stream

An influent stream is one which gains water from groundwater (also known as a âgaining streamâ).

Source: (Welsh, Podger 2008)

INRM Groups

Integrated Natural Resource Management Groups

Source: (NWC 2007)

in-stream use

The use of freshwater in situ (for example, within a river or stream). Can include recreation, tourism, scientific and cultural uses, ecosystem maintenance, hydroelectricity and commercial activities, and dilution of waste. The volume of water required for most in-stream uses cannot be quantified, with the exception of hydro-electricity generation.

Source: (NWC 2007)

instrument (WA)

A category of legal document which includes transfers, easements, leases, mortgages, etc., under any Act which affects the registration of Water Access Entitlement dealings.

Source: (NWC 2007)

Integrated Quantity and Quality Model

River system model that has been widely applied in Queensland and New South Wales over the 1990s and 2000s for the development of water sharing and water resources plans. River system model that has been widely applied in Queensland and New South Wales over the 1990âs and 2000âs for the development of water sharing and water resources plans.

Source: (Welsh, Podger 2008)

integrity

One of three main components of quality in EPAâs Information Quality Guidelines. Integrity refers to the protection of information from unauthorised access or revision to ensure that the information is not compromised through corruption or falsification.

Source: (USEPA-CREM)

Interception

Precipitation that is caught by vegetation in the catchment and later evaporated without contributing to infiltration or runoff.

interception activity

The interception of surface water or groundwater that would otherwise flow, directly or indirectly, into a watercourse, lake, wetland, aquifer, dam or reservoir that is a Basin water resource.

Source: (NWC 2007)

Source: Water Act 2007

interception works

Horizontal drains or open drains placed close to disposal basins to intercept leakage from the basin. They are usually sited within 2-20 m of the outer bank and at a depth close to the mean winter regional water table.

Source: (toolkit 20091023)

interflow

"Water that infiltrates the soil surface and then moves laterally through the upper soil horizons towards the stream channels, either as unsaturated flow, or more usually, as shallow perched saturated flow above the main groundwater level. Ward, R.C. and M. Robinson (1990) Principles of Hydrology (3rd Edition), McGraw-Hill, England."

Use: lateral throughflow

Source: (Ward and Robinson 1990)

internal spilling

A process that occurs in storages when there are multiple water owners with fixed storage shares. When one or more owners' shares in a storage are full but the overall storage is below full supply level, water belonging to those owners whose shares in the storage are full will be assigned to other water owners in the storage whose shares are not full, based on a set of predefined rules. The process continues until the storage full supply level is reached then any water remaining becomes external spill.

Source: (Gilmore et al 2008)

internal technical guidelines

Model application guidelines that usually focus on the technical aspects of modelling and are mainly intended for use by modellers. Examples are QA procedures in particular organisations, manuals for software packages which might include hints on how to best use the package, and some text books.

Source: (Refsgaard et al, 2005a)

interstate transfer (NSW)

The cancellation of a licence and subsequent grant of a corresponding interstate entitlement, or the grant of a licence after the cancellation of a corresponding interstate entitlement.

Source: (NWC 2007)

interstate water assignment (NSW)

The reduction or increase in the water allocations in the account of a water licence associated with corresponding changes in interstate entitlements.

Source: (NWC 2007)

intrinsic variation

The variability (see definition) or inherent randomness in the real-world processes.

Source: (USEPA-CREM)

inverted siphon

Structure or section of pipeline that conveys channel flow under a natural depression, river or drain.

Source: (ANCID 2001)

Source: (NWC 2007)

IPR

Indirect Potable Re-use

Source: (NWC 2007)

IQQM

Integrated Quantity and Quality Model (or Modelling). River system model that has been widely applied in Queensland and New South Wales over the 1990âs and 2000âs for the development of water sharing and water resources plans.

Use: Integrated Quantity and Quality Model

Source: (Welsh, Podger 2008)

IQQM crop model

A specific instance of a water user node where demands are estimated based on crop water requirements that take account of climatic factors.

irrigate

To supply land with water and thereby promote vegetation by means of canals, especially artificially made, passing through it.

Source: Macquarie Dictionary

Source: (NWC 2007)

irrigation area protected by drainage

Index of Stream Condition

IWCM

KPI

Key Performance Indicators

Source: (NWC 2007)

Kriging

Kriging is a group of techniques used in the analysis of spatial data and involves the interpolation of a spatially varying quantity based on the observations of that quantity at a set of near-by locations.

Source: (Stein 1999)

kT

Kilotonnes

Source: (toolkit 20091023)

L

lag time

The time delay between inflow and outflow of a river reach assuming that all flows have the same travel time.

Source: River Systems specification

Lagged flow

A link model available in Source Catchments. A routing model that assumes flow at the upstream end of the reach is translated by a fixed lag to give the flow at the downstream end of the reach, with no attenuation of the flow. Lagged Flow routing is possibly the simplest routing model that actually influences the link flow. Lagged routing is a conceptual model.

Source: (eWater CRC 2010a)

lake

A body of water (fresh or salt) of considerable size, surrounded by land.

Source: Macquarie Dictionary

Source: (NWC 2007)

LAM

Lumped Alluvial Model.

Source: (Welsh, Podger 2008)

large dam

The Australian National Committee of Large Dams (ANCOLD) has defined large dams as dams with a crest or wall height greater than 15 metres, or as dams with a dam wall height of greater than 10 metres but meeting other size criteria, including creating a reservoir capacity of no less than 1000 ML.

Use: major storage

Source: (NWC 2007)

lateral flow

Radial leakage away from a basin that occurs at shallow depth, top 4-5 m of soil.

Source: (toolkit 20091023)

lateral throughflow

Relatively rapid subsurface flow through cracks, pipes, macropores in the soil. Also referred to as lateral subsurface flow and interflow. Water that infiltrates the soil surface and then moves laterally through the upper soil horizons towards the stream channels, either as unsaturated flow, or more usually, as shallow perched saturated flow above the main groundwater level.

Source: (Welsh, Podger 2008)

Source: (Ward and Robinson 1990)

Laurenson Flow

A link routing model available in Source Catchments. A routing model based upon Mein and Laurenson (1974) that assumes that the reach storage behaves as a non-linear store given by a power law relationship between reach storage and flow. The Laurenson Flow routing model is based on physical principles.

Laurenson Lag Flow

A link model available in Source Catchments. The Laurenson Lag Flow routing method is a composite of the Laurenson Flow method and a method of lagging the resulting outflows by a multiple of the routing time step. This is the routing procedure most used in the IQQM software (Podger 1997). This model is based primarily on physical principles.

Source: (eWater CRC 2010a)

leaching

The passage of water past the plant root zone causing the flushing of accumulated salts from the root zone. (Can be induced by application of more irrigation water than is needed to supply the plant evapotranspiration requirement).

Source: (ANCID 2001)

Source: (NWC 2007)

leaching fraction

The fraction of infiltrated irrigation water that percolates below the plant root zone. For this unit to be meaningful, it needs to specify the time over which the leaching fraction is measured and the depth interval over which it is calculated.

Source: (ANCID 2001)

Source: (NWC 2007)

leakage

The process by which water from the basin moves through the floor of the basin to the soil below

Source: (toolkit 20091023)

leakage rate

The amount of water that leaks from a basin in a given time. Leakage rate may be given in volumetric units (m3/day or ML/yr) or per unit area (mm/day or ML/ha/yr).

Source: (toolkit 20091023)

lease of a water allocation (Qld)

The passing of the benefits and responsibilities associated with ownership of the allocation to another person for a fixed period. The lease of a water allocation must be registered on the Water Allocations Register.

Source: (NWC 2007)

left bank

A looped rating is an outcome of hysteresis that results in a non-unique relationship between water level and flow at a given stream location. When this relationship is plotted over time it has the shape of a loop.

loss node

A node model available in Source. The Loss node model describes the amount of water that is lost from a point in the stream network. Losses may include physical processes such as transmission losses due to evaporation and seepage, or may be used to represent losses associated with measurement error in the data used to develop the model, such as flow-measurement uncertainty. The Loss model is a conceptual model.

Source: (eWater CRC 2010a)

low level of development

Sum of water access entitlements is less than 30 per cent of sustainable yield.

Source: (NWC 2007)

lower bound pricing

The level at which to be viable, a water business should recover, at least, the operational, maintenance and administrative costs, externalities, taxes or tax equivalent regimes (not including income tax), the interest cost on debt, dividends (if any) and make provision for future asset refurbishment/replacement. Dividends should be set at a level that reflects commercial realities and stimulates a competitive market outcome.

Source: National Water Initiative

Source: (NWC 2007)

lower bound pricing (WA)

The level at which to be viable, a water business should recover, at least, the operational, maintenance and administrative costs, externalities, taxes or TERs (not including income tax), the interest cost on debt, dividends (if any) and make provision for future asset refurbishment/replacement. Dividends should be set at a level that reflects commercial realities and stimulates a competitive market outcome.

Source: (NWC 2007)

lumped routing

Models the movement of constituents based upon the kinematic wave velocity in a link division. Lumped routing is less computationally intensive and more applicable for determining constituent loads at a larger temporal resolution.

LWMP

Land and Water Management Plan

Source: (NWC 2007)

LWU

Source: (NWC 2007)

major on-stream storages

Major storages on defined watercourses.

Source: (NWC 2007)

major storage

Storages greater than 1000 megalitres in volume are considered to be major storages for the purposes of the water balance.

Source: (NWC 2007)

manual calibration

The process of model calibration where parameter values are adjusted manually by trial and error within physically defensible ranges, based on the judgement of the modeller, to obtain a match between model results and observed data that is robust and fit for purpose. The resultant set of parameter values may or may not be unique (see âequifinalityâ) and may or may not represent a local or global optimum.

Source: (James & Burgess 1982)

MAR

Managed Aquifer Recharge

Source: (NWC 2007)

marginal cost

Marginal cost is defined as the change in total cost per unit increase in output. It is the cost of producing an additional unit of output.

Source: (toolkit 20091023)

Marginal Irrigation Water Economic Index

Marginal Return due to Irrigation ($) Ã· Irrigation Water Applied (ML)

Source: (NWC 2007)

Source: (ANCID 2001)

Marginal Irrigation Water Production Index

Marginal Production due to Irrigation (kg) Ã· Irrigation Water Applied (ML)

Source: (NWC 2007)

Source: (ANCID 2001)

marginal revenue

Marginal revenue is the change in total revenue per unit increase in output

Source: (toolkit 20091023)

marker routing

Models the movement of constituents based upon the average water velocity in a link division. Marker routing provides greater resolution in modelling constituent concentration as it captures constituent âspikesâ, and is useful for forecasting impacts of management decisions on constituent concentrations

Markov chain

A stochastic process with a finite number of states in which the probability of occurrence of a future state is conditional only upon the current state; past states are inconsequential.

Source: (American Meteorology Society 2000)

mass balance

Equation based on the principle that water mass is preserved in the river system. Used to determine whether a model has been calibrated properly. In simple terms: Change in Storage = Inflows - Outflows

Source: (anonymous 2009)

matric potential

A variable describing how strongly the water within a soil matrix is bound to the soil by capillary and other forces.

Source: (ANCID 2001)

Source: (NWC 2007)

maximum allowable depletion

The maximum level of depletion to which the soil can dry without causing water deficit stress in a crop that has a fully expanded root zone. Notionally, the sum of the readily available water in each soil horizon within the plant root zone with an allowance made for the soil water extraction pattern of the crop. Also called A depletion.

Source: (ANCID 2001)

Source: (NWC 2007)

maximum order constraint node

A node model available in Source. Maximum order constraint nodes adjust orders to ensure that flows do not exceed a contraint in a river system.

MDBA

Murray Darling Basin Agreement

Source: (NWC 2007)

Mean Annual Diversion

The average volume of water taken by an allocation or group of allocations in a year. It is calculated by adding the total volume of water taken over a period of years and dividing by the number of years in that period. The calculation is performed on a water year basis.

Source: (Stanley, K. 2007)

Mean Annual Flow

The average volume of water in a year that would flow past a point and is calculated by adding the total volume of flow over a period of years and dividing by the number of years in that period. The calculation is performed on a water year basis.

Source: (Stanley, K. 2007)

Meander

One of a series of somewhat regular, sharp, freely developing and sinuous curves, bends, loops, turns or windings in the course of a stream. It is produced by a stream swinging from side to side as it flows across its flood plain or shifts its course laterally.

Source: (Eggleton 2001)

Meander wavelength

The distance of one meander along the down-valley axis.

measurement

A value in a time-series file, typically in megalitres per day.

measurement errors

Errors in the observed data that are a function of human or instrumental error during collection. Such errors may be independent or random. When a persistent bias or mis-calibration is present in the measurement device, measurement errors may be correlated among observations. In some disciplines, measurement error may be referred to as observation error.

Source: (USEPA-CREM)

measurement flume

A section of concrete channel flume with specially shaped sidewalls and/or floor that forms a constriction in the waterway. Measurement of the difference in water surface levels through the constriction allows calculation of water flow rate by referral to rating tables calibrated for the site. Particular types of measurement flume include the Parshall and Venturi flumes.

Source: (ANCID 2001)

Source: (NWC 2007)

mechanistic model

A model that has a structure that explicitly represents an understanding of physical, chemical, and/or biological processes. Mechanistic models quantitatively describe the relationship between some phenomenon and underlying first principles of cause. Hence, in theory, they are useful for inferring solutions outside of the domain that the initial data was collected and used to parameterise the mechanisms.

Source: (USEPA-CREM)

megalitre

1,000,000 litres.

Source: (NWC 2007)

memorial (WA)

Source: (NWC 2007)

mitigation water requirements (WA)

Elements of the water regime that are identified to improve diminished water quality resulting from land use practices and developments in the catchment.

Source: (NWC 2007)

model

A simplification of reality that is constructed to gain insights into select attributes of a physical, biological, economic, or social system. A formal representation of the behaviour of system processes, often in mathematical or statistical terms. The basis can also be physical or conceptual.

Source: (USEPA-CREM)

model application

Application of a fit for purpose model to address a real world problem such as supporting natural resource management decision making.

Source: (CRCCH 2005)

model code

The mathematical representation of a conceptual model in the form of a functioning computer program.

Source: (Beven 2004)

model coding

The process of translating the mathematical equations that constitute the model framework into a functioning computer program.

Source: (USEPA-CREM)

model development

The conceptualisation, specification in mathematical terms, coding, testing and verification of a modelling tool, with the end product intended to be model code which is ready to be implemented and applied to addressing real world problems.

Source: (CRCCH 2005)

Uncertainty related to the hypotheses that underlie the model itself and the model structure.

Source: (Grayson and Bloschl, 2001)

Modelling Terms

(a logical grouping of terms in this glossary)

moderate level of development

Sum of water access entitlements is between 30 per cent and 70 per cent of sustainable yield.

Source: (NWC 2007)

modes

Manner in which a model operates. Models can be designed to represent phenomena in different modes. Prognostic (or predictive) models are designed to forecast outcomes and future events, while diagnostic models work âbackwardsâ to assess causes and precursor conditions.

Source: (USEPA-CREM)

modified soil mix

To improve the slope stability, erosion resistance and permeability of the soil being used in the channel construction (in-situ or imported), soil may be treated or mixed with relatively small quantities of substances such as lime, cement, gypsum, and certain chemicals to overcome their natural deficiencies.

Source: (ANCID 2001)

Source: (NWC 2007)

module

An independent or self contained component of a model, which is used in combination with other components, and forms part of one or more larger programs.

Source: (USEPA-CREM)

monthly pattern

A specific instance of a water user node. The Monthly Demand node is used to represent demand for water on a monthly basis. This is a simple representation supporting the needs of demand and supply analysis. Monthly Demand is a conceptual model.

Source: (eWater CRC 2010a)

mortgage (WA)

Agreement to the repayment of a loan with interest, over a certain time, by the owner of the Water Access Entitlement to the mortgagee.

Source: (NWC 2007)

mortgagee (WA)

The lender of the money covered by the mortgage, for example a bank to the owner of the Water Access Entitlement.

Source: (NWC 2007)

Morton equation

Equation for estimating the evaporation rate from shallow lakes.

MSM

Murray Simulation Model.

Use: MSM-BigMod

Source: (Welsh, Podger 2008)

MSM-BigMod

The Murray-Darling Basin Authority's existing river simulation model. Murray Simulation Model - Big Model, a custom designed water resources planning model of the main stem of the Murray River system.

Source: MDBA

MSWQS

Major Storages Water Quality Study

Source: (toolkit 20091023)

multiple lines of evidence

The use of several independent evaluation strategies to address the same evaluation issue, relying on different data sources, on different analytical methods, or on both.

Source: (Centers for Disease Control and Prevention, 2006)

multiple supply path modelling

A modelling approach used when there are multiple paths from storage to demand. This includes the situations where an order can be supplied from two or more water storages, or can be routed via alternate paths such as anabranches or channels. Rules for river operation also need to be satisfied when deciding which storage(s) an order should be met from and which path to utilise for delivery. A network linear program is used to select the optimal combination of storages and paths while meeting operations constraints.

multistage flash

A series of distillation processes used to remove salt from seawater to produce water of drinking quality.

Source: (toolkit 20091023)

Murray-Darling Water Basin

Murray-Darling Basin means the area falling within the boundary described in the dataset that: (a) is titled Murray-Darling Basin BoundaryâWater Act 2007; and (b) has a dataset scale of 1:250,000; and (c) specifies the boundary of the Murray-Darling drainage division derived from the dataset that is titled âAustraliaâs River Basins 1997â and is dated 30 June 1997; and (d) is held by the Commonwealth.

Source: Water Act 2007

MUSIC

The acronym used for the Model for Urban Stormwater Improvement Conceptualisation software developed by the CRC for Catchment Hydrology to model urban stormwater management schemes

Source: (toolkit 20091023)

Muskingum Flow

A link model available in Source Catchments. The Muskingum Flow routing model makes use of the storage-outflow relationship, based on the inflow, storage dimensions, discharge, the travel time through the reach, and a dimensionless value expressing the relative effect of inflow and outflow on the storage of the reach. This model is based on physical principles.

Source: (eWater CRC 2010a)

N

natural channel storage

Volume of water in river channels. Includes the instantaneous volume of moving water, and any water in weirs which are not classed as major on-river storages or minor on-stream dams.

A type of solver/optimiser program that is used to find the minimum cost solution to network flow problems. Examples include RELAX IV and PPRN. NETLP is used in Source to find the best supply path to meet orders efficiently.

A node-link network is a simplified representation of a river system for use in computer simulation modelling.

noise

Inherent variability that the model does not characterise.

Source: (USEPA-CREM)

Groundwater modelling term synonymous with âequifinalityâ.

Source: (Grayson and Bloschl, 2001)

Normal distribution

"Also known as a Gaussian distribution, it has a characteristic bell shape that is centred around the mean. Scores occurring closer to the mean are more likely, with 68% occurring within 1 standard deviation of the mean. As values deviate more from the mean their occurrence decreases. 95% of scores occur within 2 standard deviations from the mean, and 99% occur within 3 standard deviations."

Nutrient storage

Process for nutrients to accumulate within one or more reaches of the model for a period of time, possibly to be released later. Nutrient storage would most commonly occur in large reservoirs.

Nutrient transformation

Changes in the observed forms of nutrients (for example between nitrate and ammonium) due to chemical or biological interactions within the water.

NWI

National Water Initiative

Source: (NWC 2007)

NWQMS

National Water Quality Management Strategy

Source: (NWC 2007)

O

oasis effect

This refers to the increase in evaporation rates when water bodies are surrounded by dry regions. This effect results in larger basins having lower rates of evaporation (evaporation factor 0.7 - 0.8) than smaller basins (evaporation factor close to unity).

Source: (toolkit 20091023)

objectivity

One of three main components of quality in EPAâs Information Quality Guidelines. Objectivity includes whether disseminated information is being presented in an accurate, clear, complete and unbiased manner. In addition, objectivity involves a focus on ascertaining accurate, reliable and unbiased information.

Source: (USEPA-CREM)

object-oriented platforms

Type of user interface that models systems using a collection of cooperating âobjects.â These objects are treated as instances of a class within a class hierarchy, where a class is a set of objects that share a common structure and behaviour. The structure of a class is determined by the class variables, which represent the state of an object of that class and the behaviour is given by the set of methods associated with the class.

Source: (USEPA-CREM)

observation

A time-stamp plus at least one associated measurement.

Observed Runoff

Model available in Source Catchments. Observed runoff allows the inclusion of an observed time series for rainfall runoff and uses a digital filter to separate the quick flow (surface flow) and slow flow (baseflow). Model type is a mathematical filtering algorithm.

Source: (eWater CRC 2010a)

Observed Surface Runoff

Rainfall runoff model available in Source Catchments. The Observed Surface Runoff model is used to input an observed runoff sequence of quick flow (surface flow) in place of runoff generated by a model (i.e., there is no slow flow (baseflow) component). The model can be used in situations where there is only surface flow affecting the sub-catchment (e.g. surface flow from a sewage treatment plant), or where only part of a catchment is being modelled, and observed runoff is used to represent inflows from areas that are not being explicitly modelled. This is a mass balance model based on conceptual relationships.

Source: (eWater CRC 2010a)

ocean outfall

An ocean site for discharge of a piped liquid; a (usually) deep offshore disposal area for effluent from a sewage treatment plant.

Source: (toolkit 20091023)

off-allocation

Access to rain-rejection, flood and other âexcessâ flows in the river that is granted to users in excess of their allocated water entitlement.

Source: (toolkit 20091023)

off-allocation flow sharing node

A node model available in Source.

off-river storage

A water storage (weir or lake) in the middle or lower part of a river system which is off the main stream (eg Lake Brewster in the Lachlan).

Source: (Welsh, Podger 2008)

on-farm basins

Local-scale basins that occupy parts of individual properties and are privately owned

Source: (toolkit 20091023)

on-farm storage

A large private water storage off the mainstream, eg on an irrigation property, such as a cotton farm. Some are formed by modifying billabongs but usually they are constructed at any convenient location on the property.

Source: (Welsh, Podger 2008)

on-site system

Sewage treatment equipment for converting household effluent to materials suitable for local disposal, eg septic systems, grease traps, composting toilets and household sewage treatment plants.

Source: (toolkit 20091023)

operation loss

The volume of water released from a dam to meet irrigator water orders that is subsequently not diverted by the irrigators. This occurs when irrigators reject their ordered water because local rainfall has met their water needs since a water order was placed. This âlossâ also includes an allowance for operator uncertainty in predicting how the river system as a whole will behave during the time the release water takes to travel from the dam to the users.

Source: (Welsh, Podger 2008)

options contract

A contract that gives the right, but not the obligation, to purchase or sell a good at a specified price within a specified period of time.

Source: (Productivity Commission 2006)

Source: (NWC 2007)

order time

The number of days in advance that an order has to be made to ensure that the ordered water arrives on time.

Source: (Stanley, K. 2007)

ordering phase

The fourth phase of execution within a time-step. In a regulated system, during the ordering phase Source begins at the most downstream end of the system and accumulates any orders as it passes back up the system. It takes into account any losses and forecast inflows, as well as making adjustments to orders if necessary at any minimum or maximum flow nodes. Orders are directed to specific storages where subsequent releases are made. Various ordering methods can be specified including: 1. Optimised multiple supply (NetLP); 2. Algorithm; 3. Network costs; and 4. Rules-based. In unregulated rivers, orders are compared with forecast inflows. If there is insufficient inflow to meet the orders then the available water is distributed between used according to specified rules.

Source: eWater CRC

Source: (Podger 2011)

Source: (Holz, 2010)

other supply

A type of network supply or regulated surface diversion service where customers are supplied on the basis of a roster determined by the rural water delivery agency, or the right to access water at any time subject to availability and threshold conditions. Roster periods may be varied according to different supply and demand circumstances or may be one off in nature, such as for an annual dam filling schedule for a gravity non-irrigation network supply service. Restrictions or rostering may apply in stages and in the most severe circumstances be a total ban on the taking of water.

Source: (NWC 2007)

Source: (National Performance Framework 2006-07)

outfall structure

Regulating structure located at the downstream end, or intermediate points, of a supply channel to allow safe discharge of surplus flows arising in the system due to the effects of rainfall inflow, planned channel shutdown or operational error. An outfall can also be used to drain water from the channel at the end of the irrigation season. Water released through the outfall is usually discharged to a drainage channel, natural waterway or regulating storage.

Source: (ANCID 2001)

Source: (NWC 2007)

outflow

The average flow rate out of a link or river reach during a time-step.

Source: River Systems specification

over order factor

The factor by which water orders in an IQQM model need to be increased to account for operational inefficiencies in a water supply scheme. This factor does not account for transmission losses.

Source: (Stanley, K. 2007)

overallocation

There is an overallocation for a water resource plan area if, with full development of water access right in relation to the water resources of the area, the total volume of water able to be extracted by the holders of water access rights at a given time exceeds the environmentally sustainable level of take for those water resources.

Source: (NWC 2007)

Source: Water Act 2007

overallocation (WA)

Refers to situations where with full development of water access entitlements in a particular system, the total volume of water able to be extracted by entitlement holders at a given time exceeds the environmentally sustainable level of extraction for that system.

Source: (NWC 2007)

overbank flow

Water which flows out of a river channel onto floodplains or into billabongs and wetlands during high flows. Some of this water will not return to the river when water levels subside as it goes into storage.

Source: (Welsh, Podger 2008)

overdraw

A portion of next water yearâs reserved water in a regulated system that can be used in the present water year.

Source: (Welsh, Podger 2008)

overfall weir

A channel regulator where water flows over a weir crest which can be varied in level for changing flow rates.

Source: (ANCID 2001)

Source: (NWC 2007)

over-fitting

Calibrating a model to the point where goodness of fit statistics for the calibration period are maximised/optimised but the calibrated model is not robust when used with input data for other periods.

Source: (Good & Hardin 2006)

Source: (CRCCH 2005)

overland flow

Surface runoff, which is caused when either, the ground surface is impervious, the underlying soil is saturated and cannot accommodate any more water, or because the intensity of rainfall is greater than the soilâs capacity to infiltrate it.

Source: (Welsh, Podger 2008)

overturn

An inversion process in water-bodies, where the cooler, deeper layers rise towards the surface.

Source: (toolkit 20091023)

overuse

There is an overuse for a water resource plan area if the total volume of water actually taken for consumptive use from the water resources of the area at a given time exceeds the environmentally sustainable level of take for those water resources. Note: An overuse may arise for a water resource plan area if the area is overallocated, or if the planned allocation for the area is exceeded due to inadequate monitoring or accounting.

Source: (NWC 2007)

Source: Water Act 2007

overused (WA)

Refers to situations where the total volume of water actually extracted for consumptive use in a particular system at a given time exceeds the environmentally sustainable level of extraction for that system. Overuse may arise in systems that are overallocated, or it may arise in systems where the planned allocation is exceeded due to inadequate monitoring and accounting.

Source: (NWC 2007)

owner

1. An entity that owns a share of water in a river system. 2. An entity (a state) that owns a parcel of water and has the location of that water tracked as it moves through a river system. An owner is associated with a resource assessment system.

Source: (anonymous 2009)

Source: River Systems specification

ownership phase

The seventh phase of execution within a time-step. In this phase any distribution between owners is calculated and owners' accounts are updated.

Source: (Podger 2011)

P

parameter uncertainty

Uncertainties related to parameter values.

Source: (USEPA-CREM)

parameters

Terms in the model that are fixed during a model run or simulation but can be changed in different runs as a method for conducting sensitivity analysis or to achieve calibration goals.

Source: (USEPA-CREM)

parametric variation

When the value of a parameter itself is not a constant and includes natural variability. Consequently, the parameter should be described as a distribution.

Source: (USEPA-CREM)

parsimony

The principle of parsimony calls for keeping the model as simple as possible while accounting for the system processes and characteristics that are evident in the observations and are important to the predictions, and while respecting all system information.

Source: (Hill and Tiedeman, 2007)

Partial series

A means of analysing flood frequency that involves selecting all values above a particular threshold value. Normally the threshold value is chosen so that the number of peaks chosen is between two and three times the number of years of record.

Pass Through

Filter model available in Source Catchments. The Pass Through or null filter preserves the amount of constituent generated in a functional unit (FU) and passes this to the downstream sub-catchment node. This is a conceptual model.

Source: (eWater CRC 2010a)

pay for use charge

The charge per unit of consumption levied upon a residential customer for their use, expressed as dollars per kilolitre.

Source: (NWC 2007)

peak wet weather flows

The maximum volumes of water flowing into a sewage treatment plant, down a waterway or through a catchment, during or soon after a period of heavy rainfall.

Source: (toolkit 20091023)

Penman Equation

Uses wind, net solar radiation, humidity and temperature data to estimate evaporation (E) from an open water surface.

Source: (Borrelli 2003)

Penman Montheith Equation

The Penman-Monteith equation (FAO-56) estimates reference crop evapotranspiration in mm/day, with inputs including relative humidity and wind speed.

Source: (Allen et al 1998)

percentage full

Permanent transfer of a water entitlement (licence to take water) from one licensed user to another.

Source: (Welsh, Podger 2008)

permanent wilting point

The soil matric potential below which plants wilt and fail to recover, even when placed in a humid chamber. This soil matric potential is usually estimated to be - 1.5 MPa.

Source: (ANCID 2001)

Source: (NWC 2007)

permeability

The measure of the ability of a rock, soil or sediment to transmit a fluid. The magnitude of the permeability depends largely on the porosity and the connectedness of pores spaces.

Source: (ANCID 2001)

Source: (NWC 2007)

PI

Performance Indicator

Source: (NWC 2007)

piezometer

A non-pumping well, generally of small diameter, that is used to measure the elevation of the watertable or potentiometric surface. A piezometer generally has a short well screen through which water can enter.

Source: (ANCID 2001)

Source: (NWC 2007)

pipe

A closed conveyance or carrier regardless of material, size or shape which conveys water typically for supply service. It is also a buried perforated carrier to collect subsurface drainage water.

Source: (National Performance Framework 2006-07)

Source: (NWC 2007)

piped sub-surface drainage service

A drainage service which collects and removes excess groundwater through a series of collector pipes.

Source: (NWC 2007)

Source: (National Performance Framework 2006-07)

piston-flow

The process by which leakage from the basin displaces all soil water and groundwater from areas into which it flows. No mixing or diffusion with existing water is considered to take place.

Source: (toolkit 20091023)

planted area

The area that an irrigation farmer plants in a season. The planted area may be reduced during the season if there is not enough water available to service the whole of the initially planted area.

Source: (Welsh, Podger 2008)

plug flow

Flow conditions where all âparcelsâ of inflow have the same detention time. In this document this term is also used to describe flow conditions where a constant detention time is achieved, but is less than maximum (Q/V) because of ineffective flow volume, ie âapparentâ plug flow.

Source: (toolkit 20091023)

plugin

A component model or tool that can be incorporated into Source Catchments. Usually in the form of .dll or .exe files.

PMIS

Programme Management Information System

Source: (NWC 2007)

Power Function

The Power Function is a constituent generation model that fits a rating curve describing the relationship between constituent concentration or load and discharge in linear space. This model is an empirically derived statistical function.

Source: (eWater CRC 2010a)

PPET

Point Potential Evapotransporation "The evapotransporation (ET) that would take place, under the condition of unlimited water supply, from an area so small that the local ET effects do not alter local air mass properties. It is assumed that latent and sensible heat transfers within the height of measurement are through convection only. For example, this represents the evapotranspiration which would occur from small irrigated fields with a never-ending water inflow, surrounded by unirrigated land. Point potential ET may be taken as a rough preliminary estimate of evaporation from small water bodies such as farm dams and shallow water storages."

Use: point potential evapotranspiration

Source: (Chiew 2002)

precast concrete

Concrete that is cast into its final shape before positioning.

Source: (Moore 2004)

precautionary principle

The precautionary principle is that lack of full scientific certainty should not be used as a reason for postponing a measure to prevent degradation of the environment where there are threats of serious or irreversible environmental damage.

Source: (NWC 2007)

Source: (EPA 1999)

precipitation

Rain, snow, hail, sleet, dew.

Source: (Welsh, Podger 2008)

precision

The quality of being reproducible in amount or performance. With models and other forms of quantitative information, precision refers specifically to the number of decimal places to which a number is computed as a measure of the 'preciseness' or 'exactness' with which a number is computed.

Source: (USEPA-CREM)

predictive modelling

Applying a model to analyse scenarios representing the past, the present or possible future options.

Source: (CRCCH 2005)

predictive uncertainty

Uncertainty in prediction of hydrological responses associated with: uncertainty in the input data due to sampling or interpolation error; uncertainty in simulated responses due to errors in model parameter values; and uncertainty related to the hypotheses that underlie the model itself and the model structure.

Source: (Hill and Tiedeman, 2007)

preferential flow

The process by which leakage from the basin does not pass through the entire soil matrix. Sometimes referred to as bypass flow.

Source: (toolkit 20091023)

preliminary treatment

The first processes used in a sewage treatment plant, involving screening to remove gross solids, rags and plastic and the settling of sand and grit particles.

Source: (toolkit 20091023)

pre-resource assessment phase

The third phase of execution within a time-step. In this phase account balances are adjusted prior to ordering to take account of any resource allocation rules, or accounting requirements.

Source: (Podger 2011)

pressurised network supply service

Any raw water supply service from a supply network where the minimum design residual pressure head at more than 95% of customer service points is greater than or equal to 3 metres.

Source: (NWC 2007)

Pride

A specific instance of a water user node where demands are estimated based on crop water requirements that take account of climatic factors.

Priestly Taylor Equation

The Priestley-Taylor method (Priestley and Taylor, 1972) for the calculation of daily potential evapotranspiration replaces the aerodynamic term of Penman-Monteith equation by a dimensionless empirical multiplier.

primary treatment

The first major treatment process in a sewage treatment facility, principally designed to remove a substantial amount of suspended matter, but little or no colloidal or dissolved matter. Typical primary sewage treatment processes may include clarification (with or without chemical treatment, to accomplish solid-liquid separation), grease removal and screens.

Source: (NWC 2007)

priority group (Qld)

An attribute of a group of water allocations for supplemented supply. A common water allocation security objective applies to all water allocations in the group.

Source: (NWC 2007)

private irrigation district water allocation (NSW)

The right to have water delivered to a property within a private irrigation district.

Source: (NWC 2007)

probability density function

Mathematical, graphical, or tabular expression of the relative likelihoods with which an unknown or variable quantity may take various values. The sum (or integral) of all likelihoods equals one for discrete (continuous) random variables. These distributions arise from the fundamental properties of the quantities we are attempting to represent. For example, quantities formed from adding many uncertain parameters tend to be normally distributed, and quantities formed from multiplying uncertain quantities tend to be lognormal.

Source: (USEPA-CREM)

Probable Maximum Flood

The flood resulting from Probable Maximum Precipitation (PMP), and where applicable snow melt, coupled with the worst flood-producing catchment conditions that can be realistically expected in the prevailing meteorological conditions.

Source: (Welsh, Podger 2008)

Probable Maximum Precipitation

The theoretical greatest depth of precipitation for a given duration that is physically possible over a particular catchment area, based on generalised methods.

Source: (Welsh, Podger 2008)

production function

A production function describes the rate at which resources are transformed into products or it specifys quantities and qualities of resources needed to produce a particular product.

Source: (toolkit 20091023)

programs

Instructions, written in the syntax of a computer language, that provide the computer with a step-by-step logical process. Computer programs are also referred to as code.

Use: code

Source: (USEPA-CREM)

project management

Planning, monitoring and control of all aspects of a project and the motivation of all those involved in, the aim being to achieve the project objectives on time and to the specified cost, quality and performance.

Source: (PMI 2008)

property connection sewer

A short sewer, owned and operated by the sewerage agency, which connects the main sewer and the customer sanitary drain. It includes a junction on the main sewer, a property connection fitting, a vertical riser (in some cases) and sufficient straight pipes to ensure the property connection fitting is within the lot to be serviced.

Source: (NWC 2007)

property service

Includes any water infrastructure between the water main and the internal plumbing of the property. It may be owned by the water business, and is often referred to as the âmains to meterâ service or connection. All waterplumbing downstream of the meter is usually the property ownerâs asset.

Source: (NWC 2007)

protected catchment

An area upstream of a water storage in which human activity is not permitted or is restricted so as to protect water quality values

Source: (toolkit 20091023)

provisional cap

A cap that recognises that the level of entitlement may be raised in the future.

Source: (NWC 2007)

public interaction guidelines

Source: (USEPA-CREM)

quick flow

The component of streamflow that has travelled through the catchment as interflow or across the surface as overland flow.

Source: (Welsh, Podger 2008)

R

rain rejection

This occurs when in a regulated river system ordered water is not extracted because local rainfall has met the water needs since a water order was placed.

Source: (Welsh, Podger 2008)

rain rejection flows

are released from the Hume Dam during the irrigation season but not diverted into the irrigation areas from Mulwala Lake.

Source: (toolkit 20091023)

Rainfall exceedance curve

A graphical representation of a ranking of all the rainfall values over a fixed duration in a given period, from the lowest to the highest, where the rank is the percentage of time the rainfall value is equalled or exceeded.

rainfall on storage

The average depth of rainfall over a period of time on the storage water surface

Source: (NWC 2007)

rainfall runoff

Flow of surface water from a given area resulting from the effects of rainwater and/or applied irrigation water in excess of crop water requirement and leaching.

Source: (ANCID 2001)

Source: (NWC 2007)

rainfall runoff harvesting

Water from a rainfall event that is harvested on irrigation farms via a water recirculation system.

Source: (Welsh, Podger 2008)

rainfall runoff model

A model that generates runoff from rainfall and other climatic inputs (often potential evaporation and sometimes temperature). In Source rainfall runoff models operate at the scale of the FU or sub-catchment.

Rainfall surface

Grid showing the spatial variation in rainfall depths for a given duration over an area.

rainfall volume on storage

The volume of rainfall over a period of time on the storage water surface.

Source: (NWC 2007)

RAP

Contains a suite of tools for analysing the hydrology and hydraulics of a river and their relationship to ecology.

Use: River Analysis Package

Source: (Stewardson and Marsh 2004)

Raster

A map image formed by a matrix of pixels arranged in rows columns, which can be displayed on a computer screen.

Rating curve

relationship between water level at a given location and flow rate.

raw sewage

Untreated liquid waste entering a sewage treatment plant through a system of pipes, collected from domestic and industrial sources.

Source: (toolkit 20091023)

raw water

Untreated water from a storage, stream or aquifer destined for treatment for domestic and industrial uses.

Source: (toolkit 20091023)

reach

A length of channel between two points.

Source: (ANCID 2001)

Source: (NWC 2007)

reach dead storage

The storage in a river reach that does not contribute to outflow from that reach.

Source: River Systems specification

reach length

The distance along the river reach.

Source: River Systems specification

reach storage

The volume of water stored in a river reach, which is a function of reach dead storage and flow in the reach.

Source: River Systems specification

reach width

The average river reach surface width at a specific flow or storage volume. This information is used to calculate the surface area of the reach by multiplying by the reach length.

Source: River Systems specification

reactor tank

A vessel of steel or concrete in which chemical and biological processes occur to remove biodegradable organic material by bacterial digestion and to reduce nutrient levels, during sewage treatment.

Source: (toolkit 20091023)

readily available water

Water that can be removed from a soil horizon by a crop without resulting in water deficit stress. This is often estimated to be half the âtotal available waterâ.

Source: (ANCID 2001)

Source: (NWC 2007)

REALM

"Resource Allocation Model. A tool that has been routinely used for water resources planning in Victoria, South Australia and Western Australia since the 1980's."

Use: Resource Allocation Model

Source: (Welsh, Podger 2008)

receiving water

A river, estuary or ocean site into whose waters treated effluent is discharged

Source: (toolkit 20091023)

recession

The falling limb of a hydrograph.

Source: (Stanley, K. 2007)

reclaimed water

Wastewater that has been recently treated to a standard sufficient to enable it to be recycled for some specific use

Source: (toolkit 20091023)

Recursive digital filter

A mathematical algorithm for separating baseflow from the total runoff signal.

recycled water

Treated effluent that is used by either the water utility itself, a business supplied by the water utility, or supplied through a third pipe system or urban reuse. Recycled water can be provided for onsite reuse, agriculture, irrigation,industry, potable or other use external to the treatment process.

Source: (NWC 2007)

reduced water level

Groundwater levels given with respect to height above sea-level (ie a given metres above Australian Height Datum, mAHD).

Source: (NWC 2007)

reducible uncertainty

Uncertainty in models that can be minimised or even eliminated with further study and additional data. See data uncertainty.

Source: (USEPA-CREM)

reference crop evapotranspiration

The evapotranspiration rate from a reference surface, not short of water, is called the reference crop evapotranspiration or reference evapotranspiration and is denoted as ETo. The reference surface is a hypothetical grass reference crop with specific characteristics.

Source: (Allen et al 1998)

regional natural resource management plans

Plans that cover specific regions like those developed under the Natural Heritage Trust and the National Action Plan for Salinity and Water Quality.

Source: (NWC 2007)

Source: National Water Initiative

regional natural resource management plans (WA)

Plans that cover specific regions like those developed under the Natural Heritage Trust and the National Action Plan for Salinity and Water Quality.

Source: (NWC 2007)

regional-scale basins

Basins that accept drainage water from multiple farms and irrigation districts and/or sited outside the districts themselves.

Source: (toolkit 20091023)

regulated flow

Water that is released from storage to meet downstream requirements.

Source: (Welsh, Podger 2008)

regulated resource assessment system

A way of characterising a resource assessment system based on its resource type.

regulated river

The section of river that is downstream of a major storage from which supply of water to irrigators or other users can be regulated or controlled. In NSW these storages and rivers are operated by State Water and the regulated rivers are designated by legislation.

Source: (Welsh, Podger 2008)

regulated river network

A water supply network which at its simplest may comprise a single structure such as a dam, which provides storage and the ability to regulate or control river flows, but which may comprise many structures and multiple connected regulated rivers or streams. A regulated river network would typically provide a regulated river's commercial or urban supply customers.

Source: (NWC 2007)

Source: (National Performance Framework 2006-07)

regulated river section

A section of river that is operated to manage regulated water using a set of storages and expected inflows. Regulated users in a regulated system can order water from different storages. The water available to each regulated user is determined by rules on their licences and rules used to operate the system. There can be unregulated water and unregulated users in a regulated river section.

Source: eWater CRC

regulated river supply service

A rural raw water supply service that is dependent on assets such as dams, weirs and bulk carriers and is provided at customer service points at an agreed and specified level of service and common price, which may allow for differentiated service standards or prices, but which is commonly available to customers and confers common obligations on customers. This service excludes issuing and administration of licences and may or may not include activities related to water ordering, metering and measurement. This service does not apply to any agency in South Australia in relation to the River Murray in South Australia, where the storage releases occur in the upper states in accordance with the provisions of the Murray Darling Basin Agreement.

Source: (NWC 2007)

Source: (National Performance Framework 2006-07)

regulated surface diversion service

A drainage surface diversion service that enables customers to pump or divert from a surface water source, typically a river that is regulated or controlled by a structure or structures operated by a rural water delivery agency.

Source: (NWC 2007)

Source: (National Performance Framework 2006-07)

regulated system

River system where the flow of the river is regulated through the operation of large dams or weirs.

Source: (NWC 2007)

regulated water

Water, both stored and release that can be used to supply regulated demands in a regulated river section according to the licence and operational rules in place.

Source: eWater CRC

regulating storage

Water storage located within, or close to, the channel system and used to regulate fluctuations in channel flows. Excess channel flows are directed from an Outfall Structure to the Regulating Storage and returned for use in the channel system at a time when demand increases. A Regulating Storage can reduce system water losses and improve water efficiency and service standards particularly at the downstream end of a large system.

Source: (NWC 2007)

Source: (ANCID 2001)

reinforced concrete

Concrete with metal bars or wire etc embedded to increase its tensile strength.

Source: (Moore 2004)

RELAX-IV

A computer program for optimising integer network linear programing problems. This is one of the methods available in Source for determining flow and storage distribution in a river system model.

Source: (Bertsekas and Tseng 1994)

reliability (model)

An expression of the degree to which, and consistency with which, a model meets quantitative performance criteria following calibration, validation testing and other checks, particularly sensitivity/uncertainty analysis. Statistically, reliability is inversely related to random error. Reliability is necessary but not sufficient for validity. Based loosely on: Wikipedia, http://en.wikipedia.org/wiki/Reliability_(statistics) accessed on 16 Nov. 2010.

Source: (USEPA-CREM)

reliability (water access entitlement)

The frequency with which water allocated under a water access entitlement is able to be supplied in full. Referred to in some jurisdictions as high security and general security.

Source: National Water Initiative

Source: (NWC 2007)

remote control

Remote control of channel flow regulators initiated by a signal from a distant location.

Source: (NWC 2007)

Source: (ANCID 2001)

remote sensing

Any kind of data recording by a sensor which measures energy emitted or reflected by objects located at some distance from the sensor (ie no direct ground contact).

Source: (ANCID 2001)

Source: (NWC 2007)

Source: (NWC 2007)

reuse water

Re-using water that would otherwise be wasted instead of using fresh water. Reuse water includes wastewater, stormwater, rainwater, and greywater.

Right side bank of a channel or drain when looking in the direction of flow.

Source: (ANCID 2001)

Source: (NWC 2007)

ring tank

An off-stream storage, filled by pumping during periods of high flow in the stream.

Source: (toolkit 20091023)

Riparian Particulate Model

Filter model available in Source Catchments. Conceptual model of particulate trapping in riparian buffers through the processes of settling, infiltration and adhesion. The model is primarily based on physical principles.

Source: (eWater CRC 2010a)

riparian zone

The zone adjacent to streams and rivers; usually there is some exchange of water and nutrients between this zone and the stream. An area or zone within or along the banks of a stream or adjacent to a watercourse or wetland; relating to a riverbank and its environment, particularly to the vegetation.

Source: (Welsh, Podger 2008)

Rising limb

Part of a flood hydrograph where the stream level or flow is increasing with time.

rising mains

Water diverted (by pump or gravity) from a river

Source: (Welsh, Podger 2008)

river freshes

are small excess flows (which are generated by local rainfall) in the unregulated tributaries of the Murray upstream of the forest.

Source: (toolkit 20091023)

River Manager

River Manager is a personal-computer-based application for describing and modelling the behaviour of river systems. It is part of a family of eWaterCRC products including River Operator and Source Catchments. River Manager is designed to support the construction and operation of river models that mimic river behaviour over arbitrarily-long periods (weeks, months, years, centuries). This contrasts with River Operator which is intended to support day-to-day applications.

Use: Source IMS

Source: eWater CRC

River Operator

A tool for assisting water authorities to operate regulated and unregulated river systems on a daily or seasonal basis.

Use: Source IMS

Source: (Podger 2009)

River Systems Pre-processing Tools

(software plugin) Inserts extra methods for importing input time series data into Source Catchments.

Source: (eWater CRC 2010b)

RO

Reverse osmosis

Source: (NWC 2007)

robustness

The capacity of a model to perform well across the full range of environmental conditions for which it was designed.

Source: (USEPA-CREM)

ROL

Resource Operation Licence (Qld)

Use: resource operations licence (Qld)

Source: (NWC 2007)

rolling cap

Some water entitlements are based on a rolling average of use (eg entitlements that are averaged over a three-year period), rather than a fixed annual entitlement.

Source: (NWC 2007)

ROP

Regional Operations Plan (Qld)

Use: resource operations plan (Qld)

Source: (NWC 2007)

RPM

"Filter model available in Source Catchments. Conceptual model of particulate trapping in riparian buffers through the processes of settling, infiltration and adhesion. The model is primarily based on physical principles."

Use: Riparian Particulate Model

Source: (eWater CRC 2010a)

RSMT

Source: (eWater CRC 2010a)

SAG

Scientific Advisory Group

Source: (NWC 2007)

sales water (Vic)

Lower-reliability water offered to irrigators on a seasonal basis, in proportion to their base rights, after provision has been made to meet the base rights in the following year.

Source: (Victorian Water Accounts 2008-2009)

saline disposal basins

Man-made or natural shallow depressions used for the disposal of saline water. Often referred to as evaporation basins.

Source: (toolkit 20091023)

saline groundwater

Groundwater that exceeds a salinity concentration of 3500 milligrams per litre.

Source: (NWC 2007)

salinity

sediment

Transported and deposited particles or aggregates derived from rocks, soil or biological material.

Source: (Soil Science Society of America 2008)

sediment delivery ratio

sediment delivery ratio - proportion of eroded sediment actually delivered to streams from sediment source

Source: (toolkit 20091023)

sediment load rate at sill

Parameter of the load based sediment delivery ratio filter model that defines the rate of sediment input at which all of the sediment is then delivered to the stream (with no removal).

sediment loading rate threshold

Parameter of the load based sediment delivery ratio filter model that defines the rate of sediment input at which all of the sediment is removed by the filter (with no delivery to the stream).

sediment storage

Process for sediment to accumulate within one or more reaches of the model for a period of time, possibly to be released later. Sediment storage would most commonly occur in large reservoirs or in flatter lower lying reaches of large rivers.

sedimentation

The process whereby suspended particles settle from a water column; the disposition of soil materials as the end-process of erosion.

Source: (toolkit 20091023)

seepage

The movement of water downwards or laterally through soils or permeable rock. This water can originate from a very wide range of sources, including all water bodies and most land surfaces. Seepage water may percolate far enough to reach groundwater.

Source: (Welsh, Podger 2008)

seepage meter

Covered cylindrical infiltrometers modified for use under water. Seepage meters are used for spot measurements of seepage in channels without artificial lining. The most well known seepage meter is the âIdaho Meterâ.

Source: (ANCID 2001)

Source: (NWC 2007)

seepage plume

The horizontal and vertical extent of groundwater which has been mixed with channel seepage water.

Source: (ANCID 2001)

Source: (NWC 2007)

SEIS

South East Irrigation Scheme (Tasmania)

Source: (NWC 2007)

self-extracted water

Water that is extracted by the user (generally in-situ) from either surface waters (streams or dams) or groundwater bores.

Source: (toolkit 20091023)

sequestration

The process of removing carbon from the atmosphere. Generally, sequestration is achieved through establishing tree plantations; however it can also be accomplished by other means, including chemical treatment and deep ocean air injection.

Source: (NWC 2007)

settling

Process by which particles suspended in water fall out of the water column over time and come to rest on the bottom.

settling tank

A container of water or wastewater in which solid matter in suspension forms a sediment or sludge for later removal, while the liquid flows on to the next step of the treatment process.

Source: (toolkit 20091023)

settling velocity

Rate at which particles suspended in water fall out of the water column over time and come to rest on the bottom.

sewer reticulation main

Sewer reticulation mains include all gravity sewer mains, all pressure mains (including common effluent pipelines, rising mains etc) and all vacuum system mains of any diameter. This excludes property connection sewers and pipelines carrying treated effluent.

Source: (NWC 2007)

sewerage

The system of pipes and pumps used to collect and transport sewage to, and the equipment used to treat and discharge effluent from, a sewage treatment plant.

Source: (toolkit 20091023)

sharing delivery capacity

An approach to sharing of an irrigation supply channel capacity (supplemented systems) or a water course capacity (unsupplemented) held by an entitlement holder and specified as a percentage share or volumetric supply rate at a particular time.

Source: (NWC 2007)

Source: National Water Initiative

Comprehensive national rainfall dataset managed by the Queensland Department of Natural Resources and Mines

Source: (toolkit 20091023)

SIMHYD

SIMHYD is a conceptual rainfall runoff model that estimates daily stream flow from daily rainfall and areal potential evapotranspiration data. The model contains three stores for interception loss, soil moisture and groundwater. The model has seven parameters. This is a mass balance model that is based on conceptual relationships.

Source: (eWater CRC 2010a)

Simple Urban Runoff Model

Model available in Source Catchments. Simple Urban Runoff Model is a conceptual rainfall runoff model that estimates daily stream flow from daily rainfall and areal potential evapotranspiration data. It is a simplified version of SIMHYD. The model contains three stores for interception loss, soil moisture and groundwater and model has seven parameters. This is a mass balance model based on conceptual relationships.

Source: (eWater CRC 2010a)

simulation models

Represent the development of a solution by incremental steps through the model domain. Simulations are often used to obtain solutions for models that are too complex to be solved analytically. For most situations, where a differential equation is being approximated, the simulation model will use finite time step (or spatial step) to âsimulateâ changes in state variables over time (or space).

Source: (USEPA-CREM)

siphon tube

Small flexible pipe used to discharge water from a farm channel on to land using siphonic action.

Volume of water held as snow.

Source: (NWC 2007)

SOC

State Owned Corporation

Source: (NWC 2007)

social water requirements (WA)

Elements of the water regime that are identified to meet social (including cultural) values.

Source: (NWC 2007)

soft water

Water that contains less than 200 mg/L CaCO3, lathers readily with soap or detergents.

Source: (toolkit 20091023)

Mathematical components of a conceptual water balance model that represent the ability of the soils of the catchment to store water.

soundness

One of EPA's five Assessment Factors (see definition) that describes the extent to which the scientific and technical procedures, measures, methods or models employed to generate the information are reasonable for and consistent with, the intended application.

Source: (USEPA-CREM)

Source Catchments

Catchment modelling tool developed from E2. Used for modelling, forecasting and managing the amounts of water and materials flowing across a catchment and into receiving waters.

Use: Source IMS

Source: (anonymous 2009)

Source IMS

Umbrella application environment, based on E2, which supports river management, operations and and catchments scenario types. Incorporates antecedent products such as WaterCAST, Source Catchments, River Manager, River Operator and Source Rivers. See http://www.ewater.com.au/products/ewater-source/

Source Rivers

Umbrella application environment supporting River Manager and River Operator scenarios.

Use: Source IMS

spatial interpolation

Process of estimating values of a particular quantity at spatial locations where data has not been observed from point observations of that quantity. This is commonly undertaken with rainfall, where rainfall depths are required across a catchment but observations are only available at point rainfall gauges.

special levies

Special levies are any charges that are directly levied upon properties, and are neither a fixed or pay for use charge for water or sewage (eg environmental improvement levy).

Source: (NWC 2007)

specifications

Acceptance criteria set at the onset of a quality assurance plan that help to determine if the intended objectives of the project have been met. Specifications are evaluated using a series of associated checks (see definition for checks).

Source: (USEPA-CREM)

spillway

The construction beside or in the wall of a dam to allow overflow during periods when intake exceeds storage capacity.

Source: (toolkit 20091023)

spillway volume

Volume at the spillway crest level.

Source: (NWC 2007)

spline interpolation

A form of interpolation where the interpolant is a special type of piecewise polynomial called a spline.

Source: (Rivlin 2003)

split-sample test

(Also differential split-sample test). Common approach of separating the available data into a set used for model calibration and an independent set for validation of the performance of the model. A common approach used in hydrology is to use part of the record (say the first 2/3 of the available years of data) for calibration and the remaining part of the record to validate the performance of the model using the parameter values that had previously been calibrated on the first part of the record.

splitter node

A node model available in Source. A splitter divides water travelling down a single branch into two different branches. Splitters can be used to represent distributaries (a system with multiple end-points), effluents (a split in the river into the main channel and a smaller channel), anabranches (where a smaller section of river branches away from the main channel and then rejoins the main channel further downstream), or losses (where water is leaving the system). There are two kinds of splitter:â¢ a splitter node models the behaviour of a natural system;â¢ a controlled splitter node models the behaviour of a system where the flow down the effluent can be controlled by some kind of regulating structure.

spring

An issue of water from the earth, flowing away as a small stream or standing as a pool or small lake, or the place of such an issue.

Source: Macquarie Dictionary

Source: (NWC 2007)

square kilometre

An area equal to the area of an equilateral rectangle where each side is one kilometre in length.

Source: eWater CRC

SRA

Sustainable Rivers Audit (MDBC)

Source: (NWC 2007)

SS

suspended solids. Solid particles or sediment that are supported within the water flow without regularly being in contact with the bed or sides of the stream channel.

Use: Suspended solids

SSD

Sub-surface Drip (Irrigation)

Source: (NWC 2007)

staff gauge

Streamflow gauge that records water level heights using visual observations of water levels on vertical graduated measuring sticks known as staff boards. Before the installation of automated level recording equipment, water levels were often only recorded manually from the staff gauge once per day.

stage height

Recorded water level at a streamflow gauge expressed in a distance above the defined datum for that gauge. It is common for the datum to be defined as the bed level of the stream channel at the gauge location and in that case the stage height is the depth of water in the channel. There are other situations where a different datum is used, such as Australian Height Datum or other local survey datums.

stakeholder

An individual or organisation with a vested interest in the long-term success of a project.

Source: (toolkit 20091023)

standing water level

Depth to groundwater (m) below a datum point or reference point, usually from the top of casing or natural surface.

There may be steps in the pay for use charge as usage increases past certain levels, meaning the same charge may not apply to each unit used by the customer. The steps of the pricing structure, usually in kilolitres, are the points where the usage charge applied to each customer changes.

Source: (NWC 2007)

stochastic

The random variability in the occurrence and magnitude of a parameter (eg, rainfall, streamflow, etc.)

Source: (toolkit 20091023)

Stochastic Analysis Tool

The Stochastic Analysis Tool is an abridged version of the Stochastic Climate Library (SCL) software available via the eWater Toolkit web site www.toolkit.net.au/scl. SCL is a stand alone program containing several different stochastic models for climate data generation at various spatial and temporal scales. The Stochastic Analysis Tool in Source Catchments currently contains a model for the generation of daily rainfall data for a multi-site using the transition probability matrix (with Boughtonâs correction). The resulting flow and constituent load replicates for each rainfall time series produced is the output visible to users for analysis and support. The Stochastic Analysis Tool is provided with the Source Catchments Installer.

Source: (eWater CRC 2010a)

stochastic model

A model that includes variability (see definition) in model parameters. This variability is a function of: 1) changing environmental conditions, 2) spatial and temporal aggregation within the model framework, 3) random variability. The solutions obtained by the model or output is therefore a function of model components and random variability.

Source: (USEPA-CREM)

stochastic uncertainty

The random variability in the occurrence and magnitude of an environmental variable (eg, rainfall, streamflow, etc.). This variability may cause stochastic uncertainty.

Source: (Refsgaard et al, 2005b)

stochasticity

Fluctuations in ecological processes that are due to natural variability and inherent randomness.

Source: (USEPA-CREM)

storage behaviour

The time varying change in a water storage status, influenced by rainfall, inflows, outflows and evaporation.

Source: (Welsh, Podger 2008)

storage catchment runoff

The volume of water flowing into storage over a period of time from the catchment between the headwater tributaries and the dam wall and upstream of the storage water surface.

Source: (NWC 2007)

storage demand

The volume of water that has been requested to be released from the storage. Note this may be more than the storage release.

Source: (NWC 2007)

storage inflow

The volume of water flowing into storage over a period of time that includes upstream tributaries, storage catchment runoff and rainfall on the storage.

Source: (NWC 2007)

Storage model

A link model available in Source Catchments. Storages in Source Catchments are represented as links. Thus, storages are just another specific routing scheme at an abstract level, and appear in the list of routing models. The Storage model is based upon Mandrill (EMSS) and IQQM. The Storage model works by maintaining a mass balance.

Source: (eWater CRC 2010a)

storage node

A node model available in Source. A storage represents a point in a river system where water is retained until released. A release may be controlled (eg through a valve) or uncontrolled (eg during a spill). Storages operate by maintaining water mass balance.

Storage Nutrient Deposition

An in-stream processing link model available in Source Catchments. Storage Nutrient Deposition uses the approach that in-channel storages often act as a nutrient processing system and so have an effect that can be represented by a nutrient delivery ratio. The model is primarily based on physical principles.

Source: (eWater CRC 2010a)

storage release

The volume of water released to meet downstream demands. Note this may be less than storage demand due to release or operational constraints.

Source: (NWC 2007)

Storage Sediment Deposition

An in-stream processing link model available in Source Catchments. Storage Sediment Deposition uses the approach that in-channel storages often act as a sediment processing system and so have an effect that can be represented by a sediment delivery ratio. The model is primarily based on physical principles.

Source: (eWater CRC 2010a)

storage spill

The volume of water discharged from the storage in excess of the storage demand.

Source: (NWC 2007)

stormwater

A sudden, excessive run-off of water following a storm. Surface runoff resulting from excess rainfall, usually passing quickly through a drainage area.

Source: Macquarie Dictionary

Device for measuring the level of water in a stream with time, which can then be used to estimate the flow rate of water.

subartesian water

A confined aquifer containing groundwater that will, if tapped by a bore, not flow naturally to the surface.

System of drainage collector pipes, wells, ditches and/or pumps designed to intercept and remove excess groundwater so as to control the watertable level to be below the plant root zone. Often designed to exclude or restrict entry of surface drainage and rainfall.

A node model available in Source. A supply point node represents a point in a river system where water can be diverted to meet demands.

surety (Tas)

Actual or relative probability with which a water allocation is expected to be available in any year having regard to the natural variability of the supply of water.

Source: (NWC 2007)

surface drainage service

A drainage service which collects and removes irrigation induced excess surface water, generally through surface drains.

Source: (NWC 2007)

Source: (National Performance Framework 2006-07)

surface drainage system

System of open drainage channels, modified natural waterways and/or storages designed to collect drainage from rainfall and irrigation runoff on rural lands and convey it to disposal. A system may include private, community and public works.

Source: (ANCID 2001)

SURM

"Model available in Source Catchments. Simple Urban Runoff Model is a conceptual rainfall runoff model that estimates daily stream flow from daily rainfall and areal potential evapotranspiration data. It is a simplified version of SIMHYD. The model contains three stores for interception loss, soil moisture and groundwater and model has seven parameters. This is a mass balance model based on conceptual relationships."

Use: Simple Urban Runoff Model

Source: (eWater CRC 2010a)

suspended solids

(SS) Solid particles or sediment that are supported within the water flow without regularly being in contact with the bed or sides of the stream channel.

sustainable yield (WA)

The amount of water that can be taken from a water resource system (expressed as an extraction regime) without causing unacceptable impacts.

Source: (NWC 2007)

SWMA

Surface Water Management Area

Source: (NWC 2007)

SY

Sustainable Yield

Source: (NWC 2007)

system flexibility

the degree to which the regulated system can accommodate unseasonal surplus flows, either through airspace at Yarrawonga or flow of the River Murray below bankfull capacity.

Source: (toolkit 20091023)

T

take

To remove water from, or to reduce the flow of water in or into, the water resource including by any of the following means: (a) pumping or siphoning water from the water resource: (b) stopping, impeding or diverting the flow of water in or into the water resource; (c) releasing water from the water resource if the water resource is a wetland or lake; (d) permitting water to flow from the water resource if the water resource is a well or watercourse; and includes storing water as part of, or in a way that is ancillary to, any of the processes or activities referred to in paragraphs (a) to (d).

Source: Water Act 2007

Source: (NWC 2007)

TCC

Total Channel Control

Source: (NWC 2007)

TDS

Total Dissolved Salts

Source: (NWC 2007)

temporary trade

Trade in seasonal water allocations that involves transferring some or all of the water allocated to the entitlement for the current irrigation season or for an agreed number of seasons.

Source: (Productivity Commission 2006)

Source: (NWC 2007)

temporary transfer

Transfer of a volume of water, during a water year, from one licensed user to another.

Source: (Welsh, Podger 2008)

temporary transfer (Tas)

The short term movement (max 21 days) of the right to take water from an allocation to a person who does not hold a licence. In this lease arrangement the water entitlement is retained by the seller and a temporary transfer to a person (who does not require a licence) is permitted to overcome a significant water shortage.

Source: (NWC 2007)

term transfer (NSW)

Fixed term transfer of rights under a licence to another person.

Source: (NWC 2007)

terminal seepage rate

The constant rate of seepage attained once the groundwater mound caused by channel seepage rises to the elevation of the water surface in the channel.

Source: (ANCID 2001)

Source: (NWC 2007)

Terrain Analysis Library

(within TIME) Series of routines for analysing and modifying DEM.

tertiary treatment

Principally designed to remove nutrients, such as phosphorus (typically <2 mg/L) and/or nitrogen (typically <15 mg/L). A high per centage of effluent suspended solids (typically >95 per cent) are also removed. Tertiary treatment may additionally target other contaminants of concern, eg toxicants and salt. Typical tertiary sewage treatment processes may include biological nutrient removal plants, chemical dosing of secondary plants for nutrient removal (including lagoons), enhanced pond treatment systems for nutrient removal, reverse osmosis and advanced filtration systems, membrane bioreactors and secondary treatment plus grass plots or wetlands for nutrient removal. The further processing of wastewater, which has already had secondary or advanced secondary treatment. Treatment may involve further reduction in nutrient levels, filtration, use of constructed wetlands and higher levels of disinfection, using UV radiation, ozone etc., to inactivate pathogens.

Source: (NWC 2007)

Source: (toolkit 20091023)

Thalweg

Path of the deepest thread of water in a stream or river channel.

Source: (Gordon et al 2004)

The Choke

Refers to the reach of the River Murray, between the junction of the Edward River and the Barmah township, with the lowest channel capacity (10600 ML/day) between Lake Hume and South Australia. Refer 35Â°56'S 144Â°57'E.

Source: (toolkit 20091023)

The Invisible Modelling Environment

Software development architecture specifically written for developing eco-hydrological models based upon the Microsoft .NET framework.

Source: (Welsh, Podger 2008)

Thiessen interpolation

A method of spatially interpolating point rainfall to a surface that assumes that the rainfall depth for the period at any location is the same as that recorded at the nearest rainfall gauge. For this reason it is sometimes known as "nearest neighbour" interpolation.

Thiessen weightings

Thiessen weightings are derived from the proportion of a catchment that is nearest to a particular rainfall gauge.

Thin plate splines

A method of spline interpolation that fits a surface to point observations using a polynomial function.

Threshold

A value of an algorithm or mathematical function at which there is a defined change in the behaviour of the function.

tile drain

A kind of tube drain system with linings constructed from joined slotted plastic pipes or terracotta pipes laid end to end.

Source: (ANCID 2001)

Source: (NWC 2007)

TIME

The Invisible Modelling Environment. Software development architecture specifically written for developing eco-hydrological models based upon the Microsoft .NET framework.

Use: The Invisible Modelling Environment

time series

A set of observations arranged in monotonically increasing order of time-stamp. The expression "time series" refers to the abstract concept. In an adjectival situation, use "time-series".

Source: (anonymous 2009)

Time Series Analysis

A graphical user interface that allows users to interactively investigate time series data. Designed as an interpretive tool.

Source: (eWater CRC 2010b)

time series demand

A specific instance of a water user node.

Time Series Manager

(software plugin) A tool for manipulating, infilling, cleaning and transforming time series. It can also apply any rating curve to a time series to create new time series.

Source: (eWater CRC 2010b)

time-series

When using "time series" in an adjectival situation, use a hyphen and write "time-series". For example, "time-series file". This makes it clear that "time series" is the relevant concept, as opposed to "series file".

time-stamp

A date and optional time on that date. A time-stamp represents a moment in time.

time-step

The resolution of the executing model. A time-step is a multiple of whole seconds and represents a duration of time, as distinct from a time-stamp which represents a moment in time. A daily model has a time step of 1 day. Other common time steps are 6 minutes, 1 month, 1 year.

time-step initialisation phase

The first phase of execution within a time-step. In this phase, time-series data are updated, expressions are evaluated, inflows are forecast, and demands are calculated.

Source: (Podger 2011)

Source: (Holz, 2010)

Total water use is equal to distributed water use plus self-extracted water use plus reuse water use.

Source: (NWC 2007)

TP

Total Phosphorous

Source: (toolkit 20091023)

unaccounted for water

The difference between the volume of water entering a reticulated system and the recorded use, due to system leaks and un-metered uses.

Source: (toolkit 20091023)

unbundling

The separating of historic water entitlements which bundled water, land, water use, delivery and works approvals, into separate entitlements or licences.

Source: (Productivity Commission 2006)

Source: (NWC 2007)

uncertainty

The term used in this document to describe lack of knowledge about models, parameters, constants, data, and beliefs. There are many sources of uncertainty, including: the science underlying a model, uncertainty in model parameters and input data, observation error, and code uncertainty. Additional study and collecting more information allows error that stems from uncertainty to be minimised/reduced (or eliminated). In contrast, variability (see definition) is irreducible but can be better characterised or represented with further study. A person lacking confidence about the specific outcomes of an event or action is said to be uncertain. Reasons for this lack of confidence might include a judgement of the information as incomplete, blurred, inaccurate or potentially false or might reflect intrinsic limits to the deterministic predictability of complex systems or of stochastic processes.

Source: (USEPA-CREM)

Source: (Refsgaard et al, 2005b)

uncertainty analysis

Investigates the effects of lack of knowledge or potential errors on the model (e.g, the âuncertaintyâ associated with parameter values) and when conducted in combination with sensitivity analysis (see definition) allows a model user to be more informed about the confidence that can be placed in model results.

Source: (USEPA-CREM)

uncertainty and variability

Source: (toolkit 20091023)

unregulated resource assessment system

A way of characterising a resource assessment system based on its resource type.

unregulated river section

refers to a section of a river system which is not operated for the purpose of satisfying water requirements. Users in the unregulated river section may or may not be able to extract water depending on licence restrictions, but there is no concept of ordering water. Licence types are usually stock and domestic, small scale irrigation licences or water-harvesting. Unregulated river sections, but not always, sit above regulated river sections in headwater catchments.

Source: eWater CRC

unregulated rivers

All rivers that are not regulated, including rivers where the flow is controlled by dams or weirs constructed by urban water suppliers or private users.

Source: (Welsh, Podger 2008)

unregulated surface diversion service

A drainage surface diversion service that enables customers to pump or divert under specified conditions from a surface water source, typically a stream, that is not regulated or controlled by a structure or structures operated by a rural water delivery agency.

Source: (NWC 2007)

Source: (National Performance Framework 2006-07)

unregulated system

River system where flows are not regulated by the operation of structures such as major dams or weirs.

Source: (NWC 2007)

unregulated water

is either all the water in an unregulated river section, or water in a regulated river section that does not come from a regulated source or does not form part of the regulated supply. For example, if a regulated storage spills and there is water in excess of demand requirements downstream then this excess water is considered to be unregulated water.

Source: eWater CRC

unreinforced concrete

Concrete that is not reinforced.

unsaturated zone

The zone between the land surface and the watertable. The pore spaces contained water at less than atmospheric pressure, as well other gases. Also called âZone of Aerationâ and âVadose Zoneâ.

Source: (ANCID 2001)

Source: (NWC 2007)

unseasonal surplus flows

are generated from river freshes and rain rejection flows. Also referred to as âexcess flowsâ.

Source: (toolkit 20091023)

un-supplemented water (Qld)

A water supply where reliability is not enhanced by the operation of water storage infrastructure.

Source: (NWC 2007)

upper bound pricing

The level at which, to avoid monopoly rents, a water business should not recover more than the operational, maintenance and administrative costs, externalities, taxes or tax equivalent regimes, provision for the cost of asset consumption and cost of capital, the latter being calculated using a weighted average cost of capital.

Source: National Water Initiative

Source: (NWC 2007)

Universal Soil Loss Equation

Source: (toolkit 20091023)

USTM

The 1st Order Kinetic Model k-C* model describes the decay or reduction in inflow concentration within a treatment facility such as a grass filter strip.

Use: Universal Stormwater Treatment Model

utility

One of three main components of quality in EPAâs Information Quality Guidelines. Utility refers to the usefulness of the information to the intended users.

Source: (USEPA-CREM)

UV disinfection

The use of ultraviolet light to irradiate drinking water to kill pathogens such as bacteria and viruses, and to inactivate cysts and oocysts of harmful protozoa.

Source: (toolkit 20091023)

V

validation

Where observations and simulations are compared using data that were not part of the calibration. A model is validated for a particular application and a successful validation in one example does not imply that the model is validated for universal use. Quantitative and qualitative methods for evaluating the degree to which a model corresponds to reality.

vertical flow

Leakage away from a basin that occurs vertically through the underlying groundwater.

Source: (toolkit 20091023)

volume

The amount of space that a substance or object occupies, or the amount of space within a container.

volumetric limit (Qld)

The maximum amount of water that may be taken under a water allocation for un-supplemented supply in a water year.

Source: (NWC 2007)

VWQMN

Victorian Water Quality Monitoring Network

Source: (toolkit 20091023)

W

WAC

Water Abstraction Charge

Source: (NWC 2007)

WAP

Water Allocation Plan

Source: (NWC 2007)

WAS

Water Activated Sludge

Source: (NWC 2007)

wastewater

Water which has been used at least once and hence regarded as unsuitable for immediate reuse for that purpose without treatment; water collected from domestic and industrial sources to be treated prior to discharge to the environment or for recycling for other uses.

Source: (toolkit 20091023)

water access entitlement

A perpetual or ongoing entitlement to exclusive access to a share of water from a specified consumptive pool as defined in the relevant water plan. A perpetual or ongoing entitlement, by or under law of a State, to exclusive access to a share of the water resources of a water resource plan area.

Source: National Water Initiative

Source: (NWC 2007)

Source: Water Act 2007

water access entitlement (ACT)

An entitlement to the amount of surface water or groundwater stated in the entitlement.

Source: (NWC 2007)

water delivered or protected under rules

Reduction in volumes of water committed (set aside) in storages for environmental water rules by release or delivery in accordance with the rules.

Source: (NWC 2007)

water delivery right

A right to have water delivered by an infrastructure operator.

Source: Water Act 2007

Source: (NWC 2007)

water dependent ecosystems (WA)

Those parts of the environment, the species composition and natural ecological processes of which are determined by the permanent or temporary presence of water resources, including flowing or standing water and water within groundwater aquifers.

Source: (NWC 2007)

water entitlement

A legal right to access water. An entitlement can be specified as a share of water from a consumptive pool of water as defined in the relevant water plan, or a fixed annual volume which may be restricted according to the resource assessment. Note that the licensing system in many jurisdictions has two parts to it: 1. A water access licence (i.e. the entitlement, as defined here), which is a permanent property right in the same way as land ownership title but is not associated with land title, and is tradeable. It can be expressed in terms of unit shares or some other measure, as described above. In the context of Source, each entitlement also has an account type and an account associated with it. 2. A water use licence, which is associated with a specific location and usage, and is not tradeable. In the context of Source these come into consideration when defining the properties of water users for modelling - location, demand characteristics, etc â but otherwise they do not need to be modelled.

Source: (toolkit 20091023)

water harvesting (Qld)

The taking of un-supplemented water during specified high flow events. It generally involves the pumping of water into on-farm storage for later use.

Source: (NWC 2007)

water irrigation area

The area under control of an individual water service provider (eg. an irrigation corporation, cooperative or trust, or water authority).

An authority under Part 6 of the Water Management Act 1999 to take water from a watercourse, lake or well. The licence is held by a person as personal property.

Source: (NWC 2007)

Water Management and Operation Terms

(a logical grouping of terms in this glossary)

water management areas

In general the water management areas for surface water will be the surface water management areas and groundwater management units reported in the National Land and Water Resources Audit 2000, subject to the adjustments to those boundaries made subsequently by the jurisdictions. In Tasmania the boundaries used will be those developed for the Conservation of Freshwater Ecosystems Values Project.

Source: (NWC 2007)

water orders

Water ordered by a user in a regulated river system to be supplied by the system operator. Normally the water must be ordered in advance.

Source: (Welsh, Podger 2008)

water ownership

Water ownership is concerned with assigning and tracking the ownership of parcels of water as they enter, are stored in, transit through, and exit systems. Water can be traded, both within storages as well as in transit.

Source: (eWater 2009)

A description of the variation of flow rate or water level over time; it may also include a description of water quality.

Source: (NWC 2007)

water resource

(a) surface water or groundwater; or (b) a watercourse, lake, wetland or aquifer (whether or not currently has water in it); and includes all aspects of the water resource (including water, organisms and other components and ecosystems that contribute to the physical state and environmental value of the water resource).

Source: Water Act 2007

Source: (NWC 2007)

water resource (Tas)

The waters from which water may be taken under a licence. May be a specific watercourse (eg lake, dam etc) or a variety of watercourses.

Source: (NWC 2007)

water resource plan (Qld)

Water resource plans are plans for a catchment that establish the consumptive share and environmental share of a water resource. These plans also identify any additional water available for allocation.

Source: (NWC 2007)

Water Resource Terms

(a logical grouping of terms in this glossary)

The integration of urban planning, with the management, protection and conservation of the urban water cycle, that ensures urban water management is sensitive to natural hydrological and ecological processes.

Source: (NWC 2007)

water share (Vic)

Is an on-going share of a consumptive pool of water in a particular water system. Specifies: â¢ The declared water system that the water share is tagged against. â¢ The use and source trading zones that the water share is associated with. â¢ The water system which the water share is associated. â¢ Share, expressed as the volume of the water system. â¢ Water use licence/registration with which the water share is associated (optional) â¢ The reliability class, ie whether the water share is a higher or lower reliability water share.

Source: (NWC 2007)

water sharing rules (Qld)

The water sharing rules for a water allocation specify how available water will be shared or apportioned between water allocation holders. The water sharing rules may include: â¢ rules for making announced allocations â¢ critical water supply rules-rules for sharing water during periods of low water availability â¢ carry over rules-rules about the extent to which an allocation holder can store announced allocation in water storage infrastructure for use in a subsequent year â¢ seasonal water assignment rules â¢ rules for when water may/may not be taken.

Source: (NWC 2007)

water stock

Surface and groundwater resources available in Australia for economic and environmental use.

Source: (NWC 2007)

water storage

Includes barrages, dams, reservoirs, turkey nests, tanks, weirs, constructed for or provided to contain water, regulate flows, mitigate floods, for irrigation use, power generation or for domestic and industrial consumption.

Source: (toolkit 20091023)

water supply

The system of dams, pipes, etc., by which water is supplied to a community or region.

Source: Macquarie Dictionary

Source: (NWC 2007)

water supply interruption

The water table, at atmospheric pressure, marks the variable upper limit of the unconfined aquifer. Locally a lens of clay, or other impermeable layer, can hold up the groundwater to form a perched water table.

Source: (Shaw 1994)

water tagging

An accounting approach that allows a traded water access entitlement to retain its original characteristics when traded to a new jurisdiction and/or trading zone, rather than being converted into a form issued in the new jurisdiction and/or trading zone.

Source: National Water Initiative

Source: (NWC 2007)

water tagging (WA)

An accounting approach that allows a traded water access entitlement to retain its original characteristics when traded to a new jurisdiction and/or trading zone, rather than being converted into a form issued in the new jurisdiction and/or trading zone.

Source: (NWC 2007)

Water Terms

(a logical grouping of terms in this glossary)

water tower

A tower holding a tank into which water is pumped to obtain the required pressure.

Source: Macquarie Dictionary

Source: (NWC 2007)

water trade

Describes the practice of water transfers (both permanent and temporary)

Source: (Welsh, Podger 2008)

water transfers on substitution

In water transfers on substitution, to allow transfer of a particular volume of water entitlements from Zone A to Zone B, requires the same volume to be transferred from Zone B to Zone A.

Source: (toolkit 20091023)

water treatment plant

An individual location receiving raw or partially treated water for treatment and ultimate delivery to customers.