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1st Order Kinetic Model k-C*

Model available in Source Catchments. The 1st Order Kinetic Model k-C* filter model describes the decay or reduction in inflow constituent concentration within a treatment facility such as a grass filter strip. The effectiveness of the treatment is a function of the inflow concentration, the 'background concentration' of the treatment facility (i.e. some measure of the ability of the treatment to reduce concentration), the inflow, and the treatment area. The k-C* model is the fundamental model used in the Universal Stormwater Treatment Model (USTM) of MUSIC (eWater 2009). The model is a conceptualisation of the reduction in constituent concentration that can be provided by a range of different treatment facilities. The basic equation is a decay function.

Source: (eWater CRC 2010a)

A

absolute cap

A cap beyond which there is no intention that the level of entitlements could be increased.

Source: (NWC 2007)

Source: Australian Water Resources 2005

absolute transfer (Tas)

Involves the outright sale of all or part of a licence or water allocation. The seller reduces their water allocation and the purchaser will require a new water licence or a variation to an existing licence before the transfer can proceed.

Source: (NWC 2007)

absorb

To physically or chemically assimilate a substance and include it in another; to take up gases, water, nutrients or other substances, eg by soils or plants.

Source: (toolkit 20091023)

absorption trench

The disposal field of a conventional domestic on-site effluent disposal system; an excavated area, filled with gravel with a light cover of soil from which water from a perforated pipe from a septic tank can evaporate and percolate into the surrounding soil.

Source: (toolkit 20091023)

account

Entity to keep track of the status of a water user'€™s water usage. Note that a given water user can have more than one account, and these do not necessarily have to be of the same account type.

account balance (Qld)

The remaining volume or share of water available to an account holder. The sum of all the credits to an account minus the sum of all of the debits.

Source: River Systems specification

account sharing method

Demand is distributed between resource assessment system accounts. When the account sharing method is used, water supplied to the water user is limited by the balance of the accounts and accounts are updated for orders placed or water used.

accuracy

Closeness of a measured or computed value to its '€œtrue'€ value, where the '€œtrue'€ value is obtained with perfect information. Due to the natural heterogeneity and stochasticity of many environmental systems, this “true” value exists as a distribution rather than a discrete value. In these cases, the 'true€' value will be a function of spatial and temporal aggregation.

Source: (USEPA-CREM)

activated carbon

High porosity, high surface area carbon obtained by burning organic matter in the absence of air, which possess a high capacity to remove trace and soluble components from solution; used to remove impurities causing odour and undesirable taste from drinking water by absorbing gases and various organic and inorganic molecules. Also used for removing cyanobacterial toxins from drinking water.

Source: (toolkit 20091023)

activated sludge

A rich mixture of bacteria and mineral substances that has been through a reactor tank and which is to be reintroduced, aerated and mixed with the incoming sewage; a type of sewage treatment plant in which the above process is used to break down organic matter and nitrogen compounds.

Source: (toolkit 20091023)

active volume

The volume of water currently stored that may be released through outlet structures and is equal to the current volume less the inactive volume.

Source: (NWC 2007)

Source: Water Resources Observation Network

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

Annual Exceedance Probability

Use: exceedance probability

Source: (Welsh, Podger 2008)

aeration

Exposure of a material to air so that dissolved gases may be removed; the process by which air is added to a substance or exchanged with an existing atmosphere.

Source: (toolkit 20091023)

aerobic

Adapted to the presence of oxygen; growing or occurring only in the presence of molecularoxygen; having molecular oxygen as part of the environment; bacteria that require oxygen in order to survive and multiply.

Source: (toolkit 20091023)

aerobic digestion

Breakdown of organic matter in a liquid medium in the presence of oxygen or air.

Source: (toolkit 20091023)

aerosol

A colloidal system of solid or liquid particles dispersed in a gas; very fine particles in the atmosphere, eg smoke, fog, smog.

Source: (toolkit 20091023)

aging

The progressive breakdown of organic materials through the cumulative effects of irreversible physiochemical processes over a period of time; nutrient and sediment build up in water storages over time.

Source: (toolkit 20091023)

algal bloom

A rapid increase in the mass of one or more algae or cyanobacteria (blue-green algae) in a water body, usually in response to a change in its flow, light, temperature or nutrient status.

Source: (toolkit 20091023)

algorithm

A precise rule (or set of rules) for solving some problem.

Source: (USEPA-CREM)

allocation

The percentage of the entitlement volume that is available for diversion by irrigators in the current water year in regulated rivers that use an ”annual accounting” system. This is supplied from guaranteed resources (ie from “headwater storage” or minimum flows from unregulated tributaries downstream of the storage), also adjusted for “carryover” and “overdraw”. Does not include any “supplementary water” that may become available. Allocations are announced publicly by the system operator at various times during the year.

Source: (Welsh, Podger 2008)

allotment

A unit representing a building or small group of buildings and their surrounds, up to approximately 1000 square metres.

Source: (Hardy 2009)

alluvial

Deposits of clay, silt, sand, gravel, or other particulate material that has been deposited by a stream or other body of running water in a streambed, on a flood plain, on a delta, or at the base of a mountain.

Source: (Stanley, K. 2007)

alum

Hydrated double salt of aluminium and potassium sulphates; a general term used for aluminium sulphate, used as a coagulant in water treatment; the reaction product of sulphuric acid and alumina or bauxite.

Source: (toolkit 20091023)

amalgamated (WA)

When a Water Access Entitlement is merged with another and the result is the inclusion of that Water Access Entitlement in the original.

Source: (NWC 2007)

amalgamation of water allocations (Qld)

The joining of two or more water allocations into one.

Source: (NWC 2007)

AMD

Acid Mine Drainage

Source: (NWC 2007)

anabranch

An arm of a river which separates from and later rejoins the main stream.

Source: (Moore 2004)

anaerobic

Lacking air or molecular oxygen; living or functioning in the absence of air or free oxygen; capable of survival only in the absence of oxygen; bacteria living in such conditions

Source: (toolkit 20091023)

anaerobic digestion

Decomposition of oxygenic materials under conditions of low air or oxygen supply.

Source: (toolkit 20091023)

analytical models

Models that can be solved mathematically in terms of analytical functions. For example, some models that are based on relatively simple differential equations can be solved analytically by combinations of polynomials, exponential, trigonometric, or other familiar functions.

Source: (USEPA-CREM)

announced allocation (Qld)

For a water allocation for supplemented supply, the announced allocation is the percentage of the nominal volume which can be taken during a water year. The announced allocation is declared from time to time by the holder of a resource operations licence (ROL) in accordance with the rules in the licence.

Source: (NWC 2007)

announced allocation percentage (Qld)

The percentage of the water allocationís 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)

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 EPA’s five Assessment Factors (see definition) that describes the extent to which the information is relevant for the Agency’s 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)

ARI

Average Recurrence Interval

Source: (NWC 2007)

artesian basin

A geological structural feature or combination of such features in which water is confined under pressure.

Source: Macquarie Dictionary

Source: (NWC 2007)

artesian bore

A bore whose shaft penetrates an aquifer and in which the water level rises above ground by hydrostatic pressure.

Source: Macquarie Dictionary

Source: (NWC 2007)

artificial channel storage

Volume of water in artificial channels. Includes the instantaneous volume of moving water, and any water in structures which are not classed as off river storages, on-river reservoirs or farm dams.

Source: (Sinclair, Knight, Merz 2006)

Source: (NWC 2007)

artificial wetland

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)

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.

Source: (ANCID 2001)

Source: (NWC 2007)

assessment factors

Considerations recommended by EPA for evaluating the quality and relevance of scientific and technical information. These include: (1) soundness, (2) applicability and utility, (3) clarity and completeness, (4) uncertainty and variability, (5) evaluation and review.

Source: (USEPA-CREM)

assign share component (NSW)

Reduction in share of one licence and corresponding increase in share of another (effectively changes the location and ownership of the moved share in one transaction).

Source: (NWC 2007)

assign water allocation (NSW)

The reduction in water allocations in the account of one licence and corresponding increase in water allocations in the account of another licence. (Still commonly referred to as a temporary trade)

Source: (NWC 2007)

assignment of water allocation (Vic)

The holder of a water allocation may trade the whole or a part of that water allocation to a person who is the owner or occupier of land specified in a water-use licence or water-use registration. Assignment of water trades can only be for the period of the water allocation.

Source: (NWC 2007)

associated and non-associated water shares (Vic)

Water shares are either associated with water use licenses or water use registration or classified as being "non-associated". No more than ten percent of a water system can be non-associated.

Source: (NWC 2007)

attenuation

The gradual change in shape of a hydrograph as it passes downstream along a stream channel, with a reduction in the peak flow and the hydrograph shape becoming flatter.

Source: (Shaw 1994)

AUSRIVAS

Australian River Assessment System

Source: (NWC 2007)

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 “equifinality”), 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 “inverse modelling” 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.

Source: Australian Water Resources 2005

Source: (NWC 2007)

available water determination (NSW)

The water made available from time to time to water access licence holders. Expressed as ML/unit share (but still publicised to users as percentage allocations)

Source: (NWC 2007)

average dry weather flow

The amount of water moving downstream in a catchment during the dry season; the average daily volume of wastewater entering a sewage treatment plant in dry weather.

Source: (toolkit 20091023)

B

back-flow

Movement of a liquid in a contra-direction to that intended, due to a reversal of pressures.

Source: (toolkit 20091023)

back-washing and flushing

By reversing the flow, to remove accumulated sediment particles from the sand filter in a water treatment plant.

Source: (toolkit 20091023)

bank

The slope immediately bordering the course of a river or channel along which the water normally runs.

Source: Macquarie Dictionary

Source: (NWC 2007)

Barmah-Millewa forest

is the collective name given to approximately 70000 ha of wetland habitats located on the floodplain of the River Murray between Echuca, Deniliquin and Tocumwal.

Source: (toolkit 20091023)

barrage

An artificial weir or barrier.

Source: (toolkit 20091023)

baseflow

The component of streamflow that originates from groundwater, and supports streamflows during long periods of no rainfall.

Source: (Welsh, Podger 2008)

Baseflow index

The ratio of mean annual baseflow to mean annual flow.

Baseflow separation

The process of dividing a hydrograph into baseflow and quick flow (or surface flow) components. Often this is achieved using a recursive digital filter algorithm.

basin area

The total area of the basin including the evaporative area and the area required for associated infrastructure (such as banks, interception works and buffer zones).

Source: (toolkit 20091023)

basin area percentage

The percentage of the drained area that is allocated to a saline disposal basin.

Source: (toolkit 20091023)

bathymetry

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

Source: (toolkit 20091023)

bed

The ground under a body of water.

Source: Macquarie Dictionary

Source: (NWC 2007)

benefit cost ratio

Is the ratio of total discounted benefits to total discounted costs. If discounted benefits exceed discounted costs, the ratio exceeds 1.0. All systems with ratio greater than one are financially desirable and the system with highest value is the most financially desirable

Source: (toolkit 20091023)

benthos

The sum total of organisms living in, or on, the sediment of aquatic habitats.

Source: (toolkit 20091023)

bentonite

Bentonite is a natural clay-like substance formed from the deposition of volcanic ash in seawater.

Source: (ANCID 2001)

Source: (NWC 2007)

bentonite buried membrane

A liner constructed by uniformly spreading powdered bentonite, 20 to 50mm thick, over a smooth, firm and dry channel subgrade. This layer is covered by at least 300mm of stable earth and compacted.

Source: (ANCID 2001)

Source: (NWC 2007)

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.

Source: (ANCID 2001)

Source: (NWC 2007)

best management practice

Structural and non-structural measures used to reduce the impact of development on the urban water cycle.

Source: (toolkit 20091023)

best planning practice

Actions undertaken as part of developing a concept design plan that defines and matches site characteristics to the layout and final design of infrastructure to reduce the impact of development on the urban water cycle.

Source: (toolkit 20091023)

Best Practice Modelling

eWater defines Best Practice Modelling as a series of quality assurance principles and actions to ensure that model development, implementation and application are the best achievable, commensurate with the intended purpose. In particular, the principles and actions ensure that: Models are developed according to a best practice framework, including stakeholder governance, formal capture of user requirements, technical specification and review, testing procedures as well as software quality assurance procedures and usability testing. Also, this is all undertaken through an industry standard project management framework. Models are based on the best appropriate science, and considering data and scale constraints.  Model assumptions and science are transparent and defensible; articulated in clear user documentation and supporting reference material. Model set-up, calibration and application are robust, transparent, repeatable and defensible within the constraints of data availability, and based on a consistent approach that is the best available. Model implementation is assisted by clear, unambiguous guidelines. Modelling and predictive uncertainties are clearly articulated in the context of a risk framework that stakeholders and decision-makers can understand and confidently make use of: all are based on sound decision science. A mechanism exists that allows for continuous improvement in best practice modelling as the state of knowledge and technology improves.

Source: (eWater CRC 2010c)

BFI

The ratio of mean annual baseflow to mean annual flow.

Use: Baseflow index

bias

Systematic deviation between a measured (i.e., observed) or computed value and its “true” value. Bias is affected by faulty instrument calibration and other measurement errors, systematic errors during data collection, and sampling errors such as incomplete spatial randomisation during the design of sampling programs.

Source: (USEPA-CREM)

bioaccumulation

A process whereby chemical substances are accumulated by aquatic organisms from water, directly or through the consumption of food containing the chemicals.

Source: (toolkit 20091023)

biochemical oxygen demand

A measure of the amount of oxygen needed by microorganisms to decompose organic matter in an effluent sample determined during a 5-day period in a reaction vessel at 20°C

Source: (toolkit 20091023)

biodegradable

Capable of conversion by chemical or biological processes to simple chemical substances

Source: (toolkit 20091023)

biofilm

Microbial populations that grow on the inside of pipes and other surfaces. A growth of microscopic organisms (ie bacteria and algae) living on any available surfaces (eg, plant, rock, sediment) in the water body

Source: (toolkit 20091023)

bio-filtration (bioretention) system

A grassed or landscaped swale or basin promoting infiltration into the underlying medium. A perforated pipe collects the infiltrated water and conveys it downstream.

Source: (toolkit 20091023)

biological nutrient reduction

An advanced form of the activated sludge process wherein some types of bacteria utilise the oxygen from phosphates in sewage as their energy source, reducing the phosphorus (P) content of the effluent from 10 – 15 mg/L to 1 – 5 mg/L.

Source: (toolkit 20091023)

biological treatment

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: (National Performance Framework 2006)

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.

Source: (NWC 2007)

Source: (National Performance Framework 2006)

Bird guard

A device often fitted to evaporation pans to prevent birds from using the pan to drink from. Comparative studies have shown that fitting of bird guards typically reduce recorded pan evaporation from Class A pans by 8%.

blackwater

Influent to or effluent from a septic tank or sewage system; water containing human excrement.

Source: (toolkit 20091023)

BMP

Best Management Practice best management practices

Use: best management practice

Source: (NWC 2007)

Source: (toolkit 20091023)

BOD

Biological Oxygen Demand

Source: (NWC 2007)

bore

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

Source: Macquarie Dictionary

Source: (NWC 2007)

boundaries

The spatial and temporal conditions and practical constraints under which environmental data are collected. Boundaries specify the area or volume (spatial boundary) and the time period (temporal boundary) to which a model application will apply.

Source: (USEPA-CREM)

boundary conditions

Sets of values for state variables and their rates along problem domain boundaries, sufficient to determine the state of the system within the problem domain.

Source: (USEPA-CREM)

BPEM

Best Practice Environmental Management

Source: (NWC 2007)

break even time

Is the period in years for a system’s cumulative cash flow to become positive. This represents the time period required for a system to pay for all its’ debts and after this period net positive gains start accruing.

Source: (toolkit 20091023)

broad crested weir

A type of fixed crest weir.

Source: (ANCID 2001)

Source: (NWC 2007)

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)

bulk entitlement (Vic)

An entitlement to take water held by an authority for water supply to an urban area.

Source: (NWC 2007)

bulk water

Water supplied by a water provider to another water provider.

Source: (NWC 2007)

Source: Australian Water Resources 2005

bulk water charge

A charge payable for the storage of water for, and the delivery of water to, any of the following: (a) infrastructure operators; (b) other operators of reticulated water systems; (c) other persons prescribed by the regulations for the purposes of this paragraph.

Source: (NWC 2007)

Source: Water Act 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 ‘what if scenarios’ based on historical flow, rainfall and evaporation patterns and catchment conditions.

Source: (Stanley, K. 2007)

canal

The expression “Canal” 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)

Source: Australian Water Resources 2005

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

Capital works grants are funds received and receivable from governments for specific capital works.

Source: (NWC 2007)

Source: (National Performance Framework 2006)

carryover

A portion of allocated water in regulated river systems that can be carried over from one water year to the next by water users.

Source: (Welsh, Podger 2008)

carryover reserve

Water in storage in a regulated river system in a given year that is kept in reserve to meet high security requirements in the subsequent year (sometimes referred to simply as a “reserve” to avoid confusion with “carryover”).

Source: (Welsh, Podger 2008)