Australian Water Information Dictionary

Alphabetical list of items

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palaeochannel

A deposit of unconsolidated sediments or semi-consolidated sedimentary rocks deposited in ancient inactive river channel systems.

This definition applies to:

palaeovalley

A valley formed by ancient rivers that are no longer active. Alluvial deposits can often be found here buried by other sediments.

This definition applies to:

palaeovalleys

A valley that existed in a preceding geological period - most likely infilled with sediments in subsequent geological periods thus providing a potential subsurface pathway for water in current times.

This definition applies to:

Palaeozoic

An interval of geological time spanning from roughly 540 to 250 million years ago.

Source: USGS publication: Division of geological time - Major Chronostratigraphic and geochronologic units

Related:

This definition applies to:

parameter

A measurable characteristic of a physical entity (feature); for example the temperature of water in a river.

Related: feature

This definition applies to:

PDOP

positional dilution of precision

A measure of the geometric quality of a GPS satellite configuration in the sky. A PDOP value measures the possible error in both the horizontal and vertical plane (altitude).

Related: HDOP

This definition applies to:

peak river height

The highest river height (in metres) observed during a flood event at the specified site on the river.

Related: observed river height

This definition applies to:

percentage full

The volume of water in storage as a percentage of the accessible storage capacity. Note that the percentage full may exceed 100% due to floods for example.

Related: accessible storage capacity

Synonym: % full

This definition applies to:

percentile

One of a series of threshold values that divides a set of ordered data into 100 groups with an equal number of data points in each.

For example, consider a dataset of annual rainfall totals arranged in increasing order. The 20th percentile is a value with 20% of the data below it and 80% above it. The 90th percentile is a value with 90% of the data below it and 10% above it.

Related: quantile

This definition applies to:

perched aquifer

A region in the unsaturated zone where the soil or rock may be locally saturated because it overlies a low-permeability unit.

This definition applies to:

permanent trade

Permanent trade has the same meaning as water access entitlement trade.

Synonym: water access entitlement trade

This definition applies to:

Pfafstetter reference system

The Pfafstetter coding system developed by Otto Pfafstetter in 1989, is a methodology for assigning catchment identifers based on the topology of the land surface.

Source: K.L Verdin, J.P Verdin., 1999. A topological system for delineation and codification of the Earth’s river basins, Journal of Hydrology, Vol. 218 (1-2) and J. L. Stein, M. F. Hutchinson, J. A. Stein., 2014. A new stream and nested catchment framework for Australia, Hydrol. Earth Syst. Sci., 18

Related: Geofabric Surface Catchments

This definition applies to:

pH

Value that represents the acidity or alkalinity of an aqueous solution. It is defined as the negative logarithm of the hydrogen ion concentration of the solution.

Source: Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000)

This definition applies to:

pie chart

A circular chart that is divided into sectors. A pie chart is used to display tercile forecasts with three sectors representing low flow, near median flow and high flow.

This definition applies to:

piezometer

A small pipe open at the bottom inserted into an aquifer to observe water table changes.

This definition applies to:

ping

A series of acoustic pulses, of a given frequency, transmitted by an acoustic doppler current profiler.

Source: AS 3778.1—2009 Clause 5.84. © Standards Australia Limited. Copied by the Australian Government Bureau of Meteorology with the permission of Standards Australia and Standards New Zealand under Licence 1901-c052.

This definition applies to:

planned environmental water

Planned environmental water is committed in a water plan for achieving environmental outcomes.

This definition applies to:

plant

A treatment plant, relevant to the particular urban water system, of the reporting organisation. It includes water treatment plants (WTP), wastewater treatment plants (WWTP) and water reclamation plants (WRP).

Source: Category 7 Reporting Handbook

This definition applies to:

pleistocene

An epoch which is part of the geologic timescale, usually dated as 1.8-1.6 million to 10,000 years before the present. It covers most of the latest period of repeated glaciations.

This definition applies to:

pliocene

An epoch that lasted from 5.3 million to 2.6 million years ago. It follows the Miocene epoch and is followed by the pleistocene epoch. It represents a period of general cooling and drying.

This definition applies to:

PMF

probable maximum flood

The largest flood that could conceivably occur at a particular location.

Generally, it is not physically or financially possible to provide general protection against this event. This flood defines the maximum extent of land liable to flooding. The extent, nature and potential consequences of flooding associated with the PMF event should be assessed in a Flood Study. The PMF event may form the basis of evacuation planning and the identification of refuge areas. Considerations should be given to adopting the PMF event as the design flood event for emergency services planning and for determining the location and floor levels of facilities such as telephone exchanges, police stations and hospitals. The PMF event may also be used to develop land use development guidelines in the floodplain management plan.

Source: Flood Victoria

Related: probable maximum precipitation

This definition applies to:

PMP

probable maximum precipitation

The greatest depth of precipitation for a given duration meteorologically possible for a given size storm area at a particular location at a particular time of the year, with no allowance made for long-term climatic trends.

Source: World Meteorological Organisation (1986). Manual for Estimation of Probable Maximum Precipitation. Second Edition. Operational Hydrology Report No. 1, WMO – No. 332, Geneva

Related: PMF

POAMA

predictive ocean atmosphere model for Australia

A state-of-the-art seasonal to inter-annual forecast system consisting of coupled ocean-atmosphere general circulation models (GCMs) along with sophisticated data assimilation and land-surface initialisation systems.

Source: POAMA

This definition applies to:

podosols

Soils dominated by organic matter and aluminium with or without iron. Largely confined to parts of the coastal zone and some offshore islands in Australia.

Source: R F Isbell, 1996, The Australian Soil Classification, CSIRO Publishing, Melbourne.

This definition applies to:

point velocity meter

A family of hand held acoustic based instrumentation used to measure water velocities and water depths during a discrete discharge measurement (gauging).

This definition applies to:

positional dilution of precision

A measure of the geometric quality of a GPS satellite configuration in the sky. A PDOP value measures the possible error in both the horizontal and vertical plane (altitude).

Related: HDOP

This definition applies to:

potable water

Water that is intended for use as drinking water and should materially meet the Australian Drinking Water Guidelines 2004, or equivalent.

Source: Derived from Water Regulations 2008 Schedule 3 Part 1. For the latest information on Australian Government law please go to Federal Register of Legislation

This definition applies to:

potentiometric surface

A surface representing the hydraulic head of groundwater; represented by the watertable altitude in an unconfined aquifer or by the altitude to which water will rise in a properly constructed well in a confined aquifer.

Source: USGS Definition of Terms

This definition applies to:

precipitation

All forms in which water falls on the land surface and open water bodies as rain, sleet, snow, hail, or drizzle.

Related:

This definition applies to:

predicted river height

The height (in metres) to which the river is predicted to rise at the river gauge referred to in the warning. The actual depth of floodwater will vary across the floodplain. Knowledge of past flood events, as well as estimates of flood levels from flood studies, are used by local Councils, emergency services and landowners to determine which areas are likely to be flooded from the predicted river height. The accuracy of this prediction will depend on a number of factors, including the type of flood forecasting model and its input data. Predicted river heights are subject to forecasting error and are regularly updated as more information becomes available.

This definition applies to:

Predictive Ocean Atmosphere Model for Australia

A state-of-the-art seasonal to inter-annual forecast system consisting of coupled ocean-atmosphere general circulation models (GCMs) along with sophisticated data assimilation and land-surface initialisation systems.

Source: POAMA

This definition applies to:

prescribed well area

A groundwater area in South Australia that is regulated under the Natural Resources Management Act 2004 (SA) where control of groundwater abstraction is needed to secure sustainable management and support water-dependent ecosystems. The regulation is administered by the Department for Water, SA.

This definition applies to:

primary gauge

The gauge plate which shows gauge zero elevation as described in AS 3778.2.2:2001 section 5.2.2.3.

This definition applies to:

primary measured data

Data recorded on-site, or observed or collected first hand. Also known as raw, unedited or original data.

This definition applies to:

prior period errors

Omissions from, or misstatements in, the water report entity’s general purpose water accounting report for one or more prior reporting periods arising from a failure to use, or misuse of, reliable information that:

(a) was available when general purpose water accounting reports for those reporting periods were issued and

(b) could reasonably be expected to have been obtained and taken into account in the preparation and presentation of those general purpose water accounting reports.

This definition applies to:

private irrigation diversion and extraction

Water that is self-extracted by the user usually in situ from streams and farm dams (surface water) or from bores (groundwater) for irrigation.

This definition applies to:

private stock and domestic diversion and extraction

Water that is self-extracted by the user usually in situ from streams and farm dams (surface water) or from bores (groundwater) for stock and domestic use.

This definition applies to:

probabilistic forecast

A probabilistic streamflow forecast shows the range of possible streamflow volumes and how likely it is that they will occur.

This definition applies to:

probable maximum flood

The largest flood that could conceivably occur at a particular location.

Generally, it is not physically or financially possible to provide general protection against this event. This flood defines the maximum extent of land liable to flooding. The extent, nature and potential consequences of flooding associated with the PMF event should be assessed in a Flood Study. The PMF event may form the basis of evacuation planning and the identification of refuge areas. Considerations should be given to adopting the PMF event as the design flood event for emergency services planning and for determining the location and floor levels of facilities such as telephone exchanges, police stations and hospitals. The PMF event may also be used to develop land use development guidelines in the floodplain management plan.

Source: Flood Victoria

Related: probable maximum precipitation

This definition applies to:

probable maximum precipitation

The greatest depth of precipitation for a given duration meteorologically possible for a given size storm area at a particular location at a particular time of the year, with no allowance made for long-term climatic trends.

Source: World Meteorological Organisation (1986). Manual for Estimation of Probable Maximum Precipitation. Second Edition. Operational Hydrology Report No. 1, WMO – No. 332, Geneva

Synonym: PMP

This definition applies to:

product

A water right that is tradeable, falling under the broad category of either water access entitlement or water allocation. A product may be bundled or unbundled and has various attributes such as water resource type (e.g. surface water, groundwater, regulated, unregulated) and reliability type (e.g. high, low priority).

Synonym: water product

This definition applies to:

profile

The velocity distribution of a stream cross-section.

Notes:
(1) Ensembles are measured representations of the profile.

(2) When used as a verb, profile refers to an instrument measuring stream velocity at defined positions in the cross-section.

This definition applies to:

pumpback reservoir

Collects non-potable water on an opportunistic basis downstream of a major storage. This water is transferred back to the main urban supply reservoirs in order to settle (i.e. reduce turbidity) and become part of the water supply source for that reservoir.

This definition applies to:

PVM

Point Velocity Meter

A family of hand held acoustic based instrumentation used to measure water velocities and water depths during a discrete discharge measurement (gauging).

This definition applies to: