Australian Flood Risk Information Portal
Data Entry Guidelines November 2014
GEOSCIENCE AUSTRALIA
RECORD 2015/17
Martin, S., Zeilinger, I., Middelmann-Fernandes M., Branford M., Peljo, N.
Department of Industry and Science
Minister for Industry and Science: The Hon Ian Macfarlane MP
Parliamentary Secretary: The Hon Karen Andrews MP
Secretary: Ms Glenys Beauchamp PSM
Geoscience Australia
Chief Executive Officer: Dr Chris Pigram
This paper is published with the permission of the CEO, Geoscience Australia
© Commonwealth of Australia (Geoscience Australia) 2015
With the exception of the Commonwealth Coat of Arms and where otherwise noted, this product is
provided under a Creative Commons Attribution 4.0 International Licence.
(http://creativecommons.org/licenses/by/4.0/legalcode)
Geoscience Australia has tried to make the information in this product as accurate as possible.
However, it does not guarantee that the information is totally accurate or complete. Therefore, you
should not solely rely on this information when making a commercial decision.
Geoscience Australia is committed to providing web accessible content wherever possible. If you are
having difficulties with accessing this document please email clientservices@ga.gov.au.
ISSN 2201-702X (PDF)
ISBN 978-1-925124-76-7 (PDF)
GeoCat 83895
Bibliographic reference: Martin, S., Zeilinger, I., Middelmann-Fernandes M., Branford M. and
Peljo, N. 2015. Australian Flood Risk Information Portal: Data Entry Guidelines November 2014.
Record 2015/17. Geoscience Australia, Canberra. http://dx.doi.org/10.11636/Record.2015.017
Contents
1 Introduction ............................................................................................................................................1
2 Purpose .................................................................................................................................................2
3 Intellectual Property Permissions ..........................................................................................................3
4 General Processes ................................................................................................................................4
4.1 Obtaining a log in and changing your Account Details ....................................................................4
4.2 Should a study be entered? .............................................................................................................5
5 Overall Data Capture and Quality Review Process ..............................................................................6
5.1 Home Page ......................................................................................................................................8
5.2 General Row ....................................................................................................................................9
5.3 Resources Row ..............................................................................................................................13
Uploading Resources: .......................................................................................................................14
5.4 Events Row ....................................................................................................................................17
5.4.1 Event Box .................................................................................................................................18
5.5 Inundation and Hazard Mapping Boxes .........................................................................................20
5.5.1 Flood Inundation Mapping ........................................................................................................21
5.5.2 Flood Hazard Mapping .............................................................................................................22
5.5.3 Hydraulic Modelling and Hydrological Estimate Boxes ............................................................23
5.5.4 Damage Assessment Box ........................................................................................................24
5.6 Mitigation Row ...............................................................................................................................26
5.7 Review Page ..................................................................................................................................27
Glossary..................................................................................................................................................28
Data Entry Guidelines November 2014
iii
Figures
Figure 1 Changing User Details. ..............................................................................................................4
Figure 2 Flowchart of Australian Flood Studies Database data entry process. .......................................7
Figure 3 Homepage screenshot ...............................................................................................................8
Figure 4 Screenshot of the General Row expanded. ...............................................................................9
Figure 5 Screenshot of the Resources Row Expanded. ........................................................................13
Figure 6 Screenshot of the Events Row. ................................................................................................17
Figure 7 Screenshot shows the Event box. ............................................................................................18
Figure 8 Screenshot of the Inundation and Hazard Boxes. ...................................................................20
Figure 9 Screenshot of the Flood Inundation Mapping Box. ..................................................................21
Figure 10 Screenshot of the Mapping Tab - Flood Hazard Mapping. ....................................................22
Figure 11 Screenshot of the Hydraulic Modelling and Hydrological Estimate Boxes. ...........................23
Figure 12 Screenshot of the Damage Assessment Box ........................................................................24
Figure 13 Screenshot of the Mitigation Tab. ..........................................................................................26
Figure 14 Screenshot of Review Page. ..................................................................................................27
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Data Entry Guidelines November 2014
Tables
Table 1 General Row field descriptions and guidance. ..........................................................................10
Table 2 Resources Row fields and guidance .........................................................................................16
Table 3 Events Row - Event Box fields and guidance ...........................................................................19
Table 4 Events Row - Flood Inundation Mapping Box fields and guidance ...........................................21
Table 5 Events Row - Flood Hazard Mapping Box fields and guidance ................................................22
Table 6 Events Row - Hydraulic Modelling Box fields and guidance .....................................................23
Table 7 Events Row - Damage Assessment Box fields and guidance ..................................................25
Data Entry Guidelines November 2014
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Data Entry Guidelines November 2014
1 Introduction
The Australian Flood Studies Database (AFSD) was developed in 2003-2004, and was made available
online by Geoscience Australia in 2006. The database provides metadata on Australian flood studies
and information on flood risk, a digital version of the flood study is provided where available. The
database was designed to capture Australian flood studies and summaries. It notes the techniques that
were used, the data that has been used and the data’s custodian (Middelmann et al. 20051).
The database aims to enable consultants and others tendering and undertaking work for local
government to discover quickly existing flood studies relating to an area. Organisations wishing to
commission flood studies (particularly small councils with less experience with flooding or risk
analysis) may also find exploring the database useful in order to gain experience from work
undertaken in other regions (Middelmann et al. 20051).
1
Middelmann, M., Sheehan, D., Jordon, P., Zoppou, C., & Druery, C. (2005) ‘National Catalogue of Flood Studies’. NSW
Floodplain Management Conference, 22-25 February 2005, Narooma.
Data Entry Guidelines November 2014
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2 Purpose
This document is intended to familiarise new users with the fields in the AFSD Data Entry Application as
well as provide guidance on completing data entry to a level acceptable for inclusion in the Australian
Flood Risk Information Portal (AFRIP). This guide is designed to be used by people with a range of
experience, from those with very limited experience with flood study reports through to highly
experienced flood modellers. The guidance provided sets out the minimum level of information required
for each field, and also seeks to clarify some issues that may arise during the data entry process.
Any feedback on this document may be emailed to hazards@ga.gov.au with “AFRIP Data Entry
Guidelines – November 2014” in the subject line.
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Data Entry Guidelines November 2014
3 Intellectual Property Permissions
Some documents available from the database include additional copyright or disclaimer statements.
These should be carefully read as some may require you to obtain permission before entering the
document into the database. Flood studies with such statements should be cleared for inclusion in the
database by discussing them with your direct supervisor, the person/agency who gave you the report,
the commissioning organisation and/or the authors (e.g. consultancy) who produced the report. Please
consult with your organisation’s intellectual property policy if you have any doubt.
Data Entry Guidelines November 2014
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4 General Processes
4.1 Obtaining a log in and changing your Account Details
Log in details can be provided on request to appropriate individuals. The initial request should be by
email to hazards@ga.gov.au and include the following details:

Name

Job Title

Place of Employment

State

Email Address

Telephone Contact Number
A confirmation email will be sent when your account has been set up.
Your log in and account details can be changed via the home page by clicking your username and
selecting “User Profile” as shown below after you have logged in:
Figure 1 Changing User Details.
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Data Entry Guidelines November 2014
4.2 Should a study be entered?
For a study to be included in the AFSD, it must first satisfy a number of criteria and/or undergo a
number of checks. These suitability checks are designed to ensure a consistent level of detail and
content in the AFSD. The criteria include:
1. The study must not already be in database. The database can be searched at the Australian Flood
Studies Database Search (http://www.ga.gov.au/flood-study-search/).
2. The study must be a “Flood Study”, that is, it must include some modelling (usually software
based) of flooding undertaken to a professional standard. Relevant modelling would usually
include hydrological estimates and/or hydraulic modelling.
3. Other related studies, such as floodplain management studies or plans, should be added as
attachments to the “Flood Study”, and all relevant information should be included under the flood
study entry. For example, damage assessments based on the modelling of a flood study should
always be entered into the database, preferably attached to the flood study from which they are
derived.
4. Reports where the primary focus is not to document the techniques and results of a flood study (for
example levee coanstruction, town plans, discussion papers and council meetings) should not be
included in the database as a new flood study entry. These studies may become extra attachments
to relevant flood studies if they add important content to the entry. For example, any completed or
planned action resulting from the study could be included as an attachment to the original study.
5. Documents that are in a preliminary draft state (e.g. hand written comments or an incomplete
document) should generally not be included in the database. Contacting the person who provided
the report to obtain the final report is encouraged. If the draft is complete and currently in use by
the commissioning organisation, then it should be entered into the database.
Studies that have not considered these suitability checks may not pass quality assurance procedures
if submitted.
Data Entry Guidelines November 2014
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5 Overall Data Capture and Quality Review
Process
Flood study data suitable for capture in the database includes general information about the study, flood
study analyses, page references to survey information, mapping (possibly georeferenced from pdf
images), flood mitigation strategies and digital copies of relevant documents (scanned if necessary).
New reports are submitted using the review page which includes all of the information entered.
Once a study has been submitted, the metadata entered undergoes a quality assurance process at
Geoscience Australia. During this process a submitted study may be returned to the submitter with a
request for changes or additional information. Additional information that has been clearly missed
during data entry or missing appendices and other attachments may be sought. After the requests
have been addressed the user can re-submit the study.
Further detail on the attributes captured in the database are covered in the following pages.
The process of data entry into the Australian Flood Studies Database is summarised in Figure 2.
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Data Entry Guidelines November 2014
Figure 2 Flowchart of Australian Flood Studies Database data entry process.
Data Entry Guidelines November 2014
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5.1 Home Page
Figure 3 Homepage screenshot
The Homepage that is displayed after logging on is displayed above. “Current Work” shows entries that are currently in a “saved” state, that is you have
created them but not yet submitted them and entries that have been “Returned” with instructions to make changes before re-submitting. “My Submitted” shows
a list of your studies that you have submitted and allows you to make more changes to them (they will then have to be re-submitted) or track their progress
through the QA process until they are published on the Australian Flood Risk Information Portal.
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Data Entry Guidelines November 2014
5.2 General Row
Figure 4 Screenshot of the General Row expanded.
The general row captures all mandatory information required for entry into the database as well as a comments field and other information. This information
can usually be sourced from the introductory parts of a flood study such as the Executive Summary, Introduction and Title pages. Where there are multiple
documents attached to the one entry (e.g. Flood Study, Floodplain Risk Management Study), the mandatory fields should be filled out using information from
the Flood Study.
Data Entry Guidelines November 2014
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Table 1 General Row field descriptions and guidance.
Field Name
Definition
Field Rules
AFSID
The Australian Flood Studies Identifier
Computer generated number which
(AFSID) for the Flood Study. The AFSID is a identifies the Flood Study uniquely.
unique identifier automatically assigned by
Geoscience Australia to unambiguously
identify a Flood Study entry. Typically a
Flood Study and related Floodplain
Management Studies and Plans are
assigned the same AFSID.
May be useful when discussing flood studies, especially where title
names are similar.
Study name
The name of the flood study.
This should accurately reflect the title given to the report on the title
page but should not include information on the version of the report
(final draft, draft, final etc…). If the report is a draft this should be noted
in the comments section of the general tab.
Commissioning
organisation
The original organisation that commissioned Do not include trailing Pty Ltd or other Usually a council, but can sometimes be both a Council and another
the study.
similar abbreviations.
consultant. Do not include full stops.
Use a capital letter for each word in
the title Exceptions:
and, in, of, to, a, on etc…
Do not include full stops. Current
character limit of 300.
Lead consultant
/ organisation
The organisation completing the majority of
the work and authoring the flood study.
Use a capital letter for each word in
the title Exceptions:
and, in, of, to, a, on etc…
Do not include full stops. Current
character limit of 300.
Where multiple organisations are involved in the creation of a study, a
close reading of the introduction text can help you decide which
organisation was ultimately responsible for the report. Do not include
full stops.
Date report
commissioned
The date the report was commissioned.
A mandatory four digit year and an
optional two digit month.
This date is sometimes found in the first few sentences of Executive
Summaries or other places detailing the history of the study itself.
Date report
completed
The date the report was completed.
A mandatory four digit year and an
optional two digit month.
Most accurate date is usually found in a version history part of the
study on the first few pages.
Use a capital letter for each word in
the title Exceptions:
and, in, of, to, a, on etc…
Do not include full stops.
Field Entry Guidance
Watercourses in Names of rivers or creeks included in the
Study
study.
e.g. Murrumbidgee River; Queanbeyan
River.
If more than one, values are delimited This should be a complete list of all the watercourses included in the
by semicolons.
modelling of the study. These could include creeks, rivers, drains etc.
This information can usually be found summarised in the introductory
sections of the report with more detail in the modelling specific
sections.
State / Territory
Select one or more from the authority
list.
10
The Australian State or Territory on which
the study focuses on.
More than one State or Territory can be entered for a study. For
example studies along the Murray River may be relevant to more than
one state.
Data Entry Guidelines November 2014
Field Name
Definition
Field Rules
Field Entry Guidance
Comments
Optional field for additional general
information about the flood study.
Free text. Current character limit of
1000.
Proper sentences or else a short note
without a full stop.
Include information such as the version of the report if it is not the final.
Anything else notable about the study that does not fit into the
comments sections of the other tabs can be noted here. For example
“The attached report is missing some appendices and figures”.
Surveys in Study A check box and page reference to where
- Floor
more information regarding Floor Level
Surveys may be found.
Free Text
Floor level surveys are usually produced to inform damage
assessments and are most frequently found in the “”Floodplain Risk
Management Studies and Plans as opposed to the flood studies
themselves.
Surveys in Study A check box and page reference to where
- Terrain
more information regarding Terrain Surveys
may be found.
Free Text
Terrain surveys usually produce cross sections that are used in the
flood modelling. Photogrammetry can be used in older surveys but
most often the format is a combination of LiDAR (sometimes referred
to as Airborne Laser Survey, ALS) data with cross-section field
surveys.
Flood Frequency A check box and page reference to where
Free Text
Analysis
more information regarding Flood Frequency
Analysis may be found.
Flood studies often have sections detailing the methods and results of
flood frequency analysis that are used to inform model scenario
creation, searching the pdf for keywords such as “Flood frequency”
should help find these sections.
Latitude and
longitude
The latitude and longitude of the Flood
Study extent centroid.
Represent the study area logically. For example if the study is focused
on a single town (e.g. AFSID 2794) then the latitude and longitude
should be those of the town. However if the study encompasses large
areas (such as AFSID 2781) then the latitude and longitude should be
an approximation of the centre of the study area. In cases where the
study area is not clear and the study is wide ranging (e.g. AFSID 2875)
then the latitude and longitude entered should reflect a logical main
population centre in that area.
Abstract
Additional information about the content of
Free text field with a character limit of
the study for example a brief summary of the 1000
contents and goals of the study.
Is auto filled with a general statement that is acceptable for meeting
the minimum metadata standards. It is encouraged that it be changed
to summarise the specific goals methods and outcomes used in the
study.
Lineage
Statement
A statement of the history of the data, who
created it and when, when if ever was it
updated and by whom etc…
Is auto filled for convenience with text that will comply with the
metadata standard if left untouched. It is encouraged that the field is
filled out with lineage information specifically relating to the study.
Summary information about the number of drafts written and the
drafting process for example would be valuable.
Data Entry Guidelines November 2014
No more than 3 decimal places.
Free text field with a character limit of
1000
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Field Name
Definition
Field Rules
Organisation
The custodian organisation for the final
Flood Study to be contacted when any
clarification or further information is desired.
Usually the commissioning organisation.
Do not include trailing Pty Ltd or other This will usually be a commissioning organisation, state government
similar abbreviations.
agency or, in rare cases, a federal government agency or the flood
study authors themselves.
Use a capital letter for each word in
the title Exceptions:
and, in, of, to, a, on etc…
Do not include full stops. Current
character limit of 1000
Address
The address of the flood study custodian
organisation.
Follow the format: Street Number
Street Name, Suburb, State,
Postcode.
For example:
16 Flood Street, Deluge, NSW, 7777
Individual Name
Name of an individual to be contacted with
queries and request for clarification relating
to the flood study content.
Must be filled out if Position is missing In the case when an individual cannot be identified as an appropriate
point of contact, internet searches of the custodian organisation may
help to find at least an appropriate position to be entered into the
Position field.
Position
Position within the custodian organisation to
be contacted with queries and request for
clarification relating to the flood study
content.
Must be filled out if individual name is
missing
Internet searches of the custodian organisation should provide a
position to enter into this field. If nothing flood specific can be found, a
general “enquiry’s” position found on a “Contact us” section of the
website may be sufficient with a matching email in the “Email” field.
Email
Email of the custodian organisation
Must be a valid email address
If not known by the data entry person, may be sourced through
searches for flood related contacts on the custodian organisation’s
website.
Phone
Phone number of the custodian organisation Must be a valid phone number
If not known by the data entry person, may be sourced through
searches for flood related contacts on the custodian organisation’s
website.
Fax
Fax number of the custodian organisation
If not known by the data entry person, may be sourced through
searches for flood related contacts on the custodian organisation’s
website.
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Must be a valid fax number
Field Entry Guidance
In the case where the address of the most appropriate point of contact
is not readily obtainable, the address of a state government
department with environmental or hazard responsibilities may suffice.
Data Entry Guidelines November 2014
5.3 Resources Row
Figure 5 Screenshot of the Resources Row Expanded.
The Resources row enables you to upload files and link online data to the study record. Doing this is valuable because it helps users of the search
applications - they see links straight to the study documents and maps.
Here you must upload a digital copy of the document you are using to complete the data entry. If you only have a hard copy please upload a scanned version
of it here. If the study being upload is larger than the 150 Mb limit please use software to create a multi volume zip and upload each piece separately (see
AFSID 2814 for an example).
Data Entry Guidelines November 2014
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Any set of clearly related documents should be uploaded. For example AFSID 2408 includes a report on flood prioritisation. Where such directly relevant
reports exist there is no reason not to include them as well commented, titled and uploaded attachments. This information is requested because while minor
reports and other strictly “non-flood study” documents are not valuable as entries in their own right, attached logically to a relevant flood study they have value.
Attached files should be logically named, for example 20040748RA4.pdf could be replaced with Dry_Creek_Floodplain_Mapping.pdf.
Uploading Resources:
About Files
1. Select or drag in files
2. Set ‘Resource Content Type’ to ‘Study Document’
3. Set ‘Resource Type’ to ‘File’
4. Enter the ‘Short Title’ (this will be a link in the search application, so please make it short but useful)
5. Enter the ‘File Description’
6. Enter any Terms and Conditions associated with the upload
7. Decide if users must be forced to acknowledge any Terms and Conditions.
About Maps
The system supports maps in the following formats:

Shapefile (the open ESRI format, not the PGDB ‘Personal GeoDataBase’ format)

Raster (the open ESRI Grid format not the proprietary binary format)

WMS (Web Map Service, an open source standard for transferring map images)

WFS (Web Feature Service, an open source standard for transferring geospatial data).
Shapefile maps are in a file format commonly used to import and export data from a GIS. They are usually made available as a zip file. If they are in a
directory structure, you will need to zip each map to its own separate Shapefile. For more information on Shapefiles see here.
WMS and WFS maps are usually published from a server or cloud-based GIS. Both return data in response to simple URL text requests. A WMS returns a
map image. A WFS returns a set of points, lines and shapes that can be used to create a map. You will need to know the URL for the service. There may also
be a separate URL for the legend.
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Data Entry Guidelines November 2014
To load a map Shapefile:
1. Check if the map shows depths or just the extent of inundation
2. Set ‘Resource Content Type’ to ‘Inundation Extent Map’ or ‘Inundation Depth Map’
3. Set ‘Resource Type’ to ‘File’
4. Enter the ‘Short Title’ (this will be a link in the search application, so please make it short but useful)
5. Enter the ‘File Description’
6. Enter any Terms and Conditions associated with the upload
7. Decide if users must be forced to acknowledge any Terms and Conditions.
To load a map WFS or WMS:
1. Check if the map shows depths or just the extent of inundation
2. Enter the ‘URL’ for the service
3. Click the ‘Select’ button and choose an ‘Endpoint’ from the list of maps available at the URL
4. Set ‘Resource Content Type’ to ‘Inundation Extent Map’ or ‘Inundation Depth Map’
5. Set ‘Resource Type’ to ‘WMS’ or ‘WFS’
6. If uploading a WMS enter the ‘WMS Layer Name’ (this is often just a number)
7. If uploading a WMS enter the ‘WMS Legend URL’
8. Enter the ‘Short Title’ (this will be a link in the search application, so please make it short but useful)
9. Enter the ‘File Description’
10. Enter any Terms and Conditions associated with the upload
11. Decide if users must be forced to acknowledge any Terms and Conditions.
Data Entry Guidelines November 2014
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Table 2 Resources Row fields and guidance
Field Name
Definition
Field Rules
Field Entry Guidance
Select files button
Used to choose the actual electronic
file to be attached to the Flood Study
record.
Must be less than 150 MB.
Name must not include
any spaces, replace them
with underscores.
If the study comprises many files i.e. the report is split into chapters, figures
and appendices for example (see AFSID 2874), then there should be a best
effort to put all the pieces together and form one complete pdf (using adobe
acrobat pro for example). If this is not possible files should all be zipped
together in a logical way and uploaded.
Resource URL
The URL used to connect to the WFS
or WMS service
Resource content type
Tag to identify the resource as a study
document or particular map type.
Resource type
A tag for the resource being supplied.
If WMS is selected the
fields WMS Layer name
and WMS Legend URL
should also be filled out.
Documents and data such as pdfs and shapefiles/rasters should be tagged as
“file”. WFS or WMS can also be tagged here as appropriate.
WMS layer name
An identifier to help the WMS service
supply the correct map
WMS legend URL
The URL that supplies the maps
Legend
Short title
Text string will be used as a link on the
external search page.
File description
A description of the file content.
Terms and Conditions
A field to house any Terms and
Conditions relating to the viewing
and/or use of the resource being
uploaded.
If there is any restrictions on the use of the resource it should be entered here
and will be available for users to read.
Force Acknowledgement
of Terms and Conditions
before allowing
download.
A check box to be flagged if users of
the resource are required to
acknowledge Terms and Conditions of
the resource before downloading it.
This gives the data supplier an additional mechanism to ensure the data they
are supplying has its related terms and conditions well and forcefully presented
to users before downloading.
16
This is often just a number.
Short titles are useful here such as “Wallumbilla Flood Study” instead of
“Wallamballa Flood Study for the investigation of drainage problems” for
example.
Free text.
Current character limit of
1000.
Proper sentences else a
short note without a full
stop.
In the absence of any other descriptions use of the following template is
recommended:
Where a version (Draft, Final) is clear from the report:
Flood Study Title – Version – Date (Month Year)
For example:
Emu Creek Flood Study – Final Report – February 2007.
Where the version is not clear, omit the version from the description.
Data Entry Guidelines November 2014
5.4 Events Row
Figure 6 Screenshot of the Events Row.
The events row can capture information about three types of analysis and two mapping types often present in flood study reports; namely: Hydrological
Estimates, Hydraulic Modelling, Damage Estimates and Inundation & Hazard Mapping. The events row can be the most time consuming to fill out and
requires the closest reading of the study material to obtain the relevant information. This information can be found in section titled Modelling Methodology,
Hydrological Modelling, and Hydraulic Modelling”. This information may be summarised in the Introduction and the “Executive Summary” but usually you will
need to read the text in the relevant section of the report to obtain the details needed to fill out the fields on this section. A check of the studies Table of
Contents can help you quickly locate these sections.
Data can be entered for hydrological estimates, hydraulic modelling and damage assessment analyses as well as for any mapping associated with the event.
Each piece of information that can be associated with an event is described in the following.
Data Entry Guidelines November 2014
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5.4.1 Event Box
Figure 7 Screenshot shows the Event box.
The Event Box is the base of each Event Row and records the basic information that relates to the event being simulated in the study; such as the nature of
the event, its likelihood and comments. All of the modelling undertaken as part of the study and maps produced from the modelling is recorded in the rest of
the Event Row. The information required here can often be first identified from lists of figures (for example sets of figures for 10, 25, 50 and 100 ARI
scenarios) and found in detail somewhere at the beginning of Modelling Methodology or similar sections that summarise the suite of modelling undertaken in
the study.
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Data Entry Guidelines November 2014
Table 3 Events Row - Event Box fields and guidance
Field Name
Definition
Average recurrence
interval (ARI)
A statistical estimate of the average period in years
If the term ‘Other’ is
between the occurrence of a flood of a given size or
selected a value is
larger than the selected event. For example, floods
required.
with a discharge as great as, or greater than the 20
year ARI flood event will occur on average once every
20 years.
Climate change
Checked if the event modelled included climate
change assumptions.
Event date
The year and month of the historical event.
ARI comments
Free text entered by the user about the ARI.
Used for calibration
To be checked in the case of historical scenarios
used to calibrate the software model.
Usually mentioned in sections introducing the modelling method if not
in a section titled “Calibration”.
Used for validation
To be checked in the case of historical scenarios
used to validate the software model.
Usually mentioned in sections introducing the modelling method if not
in a section titled “Validation”.
Data Entry Guidelines November 2014
Field Rules
Field Entry Guidance
If the ARI/AEP has incorporated climate change, the scenario should
be noted here e.g. Applied 1m sea level rise.
Free text. Current
character limit of 1000.
Useful comments here include distinguishing features of the modelled
scenario, for example if it was specific to a set of mitigation options.
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5.5 Inundation and Hazard Mapping Boxes
Figure 8 Screenshot of the Inundation and Hazard Boxes.
The two Mapping Boxes record information about two types of maps often present in flood studies and floodplain risk management documents: Flood
Inundation Maps and Flood Hazard Maps. These maps can be found throughout flood study documents, and can sometimes form large appendices.
Sometimes a study may be missing the relevant appendices, figures may form a separate document that you do not have, or the figures may just be missing
from the report. In these cases the List of Figures typically following the reports Table of Contents or careful skimming of the document can help ascertain how
many figures the report produced. These figures should be entered into the appropriate Event Rows and comment made that at the time of data entry the
figures were not available and may not necessarily be in the provided resources.
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Data Entry Guidelines November 2014
5.5.1 Flood Inundation Mapping
Figure 9 Screenshot of the Flood Inundation Mapping Box.
Flood inundation maps display the extent or depth of flooding for specific modelled scenarios and can be presented in different ways. They are usually easy to
find during a skim of the report or reading a ‘List of Figures. If the document you are using for data entry clearly refers to figures but those figures are missing
from your digital copy then contact your source for the document and request the figures. You should still record those maps in the Mapping Tab fields.
Table 4 Events Row - Flood Inundation Mapping Box fields and guidance
Field Name
Definition
Field Rules
Field Entry Guidance
Comments
Additional information about the flood
inundation mapping.
Free text.
Current character limit of 1000.
Proper sentences else a short
note without a full stop.
Use this field to describe constraints or issues relating to the maps raised in
the report such as “Maps to be updated when the ~ levee is completed.”
- Maps missing from study. A comment stating; at the time of data entry the
figures were not available and may not necessarily be attached to the study.
Main purpose(s)
Standardised classifications of the
main purpose for which the flood
inundation map was developed.
If the term ‘Other’ is selected an The purpose of the mapping is often the same as the purpose of the study as
entry is required.
a whole and this information can be obtained from the Introductory sections
of most flood studies. When in doubt “Flood Risk analysis” and “Determine
Flood Behaviour” are general enough to fit most situations.
Select Primary
Mapping Resource
Used to choose a primary mapping
resource.
Data Entry Guidelines November 2014
This is where an event is linked to any uploaded map that the simulation of
that event produced. Linking events with uploaded shapefiles here will
enable them to be viewed in the Portal.
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5.5.2 Flood Hazard Mapping
Figure 10 Screenshot of the Mapping Tab - Flood Hazard Mapping.
Flood hazard maps generally delineate several hazard levels (for example low, medium and high hazard) which are defined through a combination of
parameters, such as water depth and velocity. If present they are usually easy to locate through a List of Figures or a skim of the document. If the document
you are using for data entry clearly refers to figures but those figures are missing from your digital copy, then contact the source of the document and request
the figures.
Table 5 Events Row - Flood Hazard Mapping Box fields and guidance
Field Name
Definition
Field Rules
Comments
Additional information about the Flood Hazard
Mapping.
Free text.
Current character limit of 1000.
Proper sentences else a short note
without a full stop.
Hazard guideline
Standardised classifications which define what
combinations of parameters (for example, water
depth and velocity) describe the different hazard
zones (for example, low, medium and high hazard).
If the term ‘Other’ is selected an entry is
required.
Other hazard
guidelines
Non-standard Hazard Guideline.
Must be filled in if “Other” is chosen in
the above field.
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Field Entry Guidance
Not often given in reports although if the guidelines
used were the 1986 NSW Floodplain Development
Manual this is usually stated in the text introducing the
maps.
Data Entry Guidelines November 2014
5.5.3 Hydraulic Modelling and Hydrological Estimate Boxes
Figure 11 Screenshot of the Hydraulic Modelling and Hydrological Estimate Boxes.
The Hydraulic Modelling section is intended to capture information about the software used to model the various scenarios hydraulically. Hydraulic models
simulate water flow, evaluating flow parameters such as water level, extent and velocity.
The Hydrological Estimates section is intended to capture information on the methods, software and scenarios used in the study. This may involve the
evaluation of peak flows, flow volumes and the derivation of hydrographs for a range of floods.
Table 6 Events Row - Hydraulic Modelling Box fields and guidance
Field Name
Definition
Field Rules
Field Entry Guidance
Models(s)/Method(s) The method (methodology or
used
approach) used to develop the
hydraulic model.
If the term ‘Other’ is selected a
value is required.
This information is usually readily available in a flood study, be careful, when
there is talk of multiple models in the one document, to identify the model that
actually produced the studies main results and scenario simulations.
Comments
Free text.
Current character limit of 1000.
Proper sentences else a short
note without a full stop.
To be used sparingly.
Items noted here tend to include specific details found in the modelling
sections that you deem important enough to be recorded e.g. “The authors of
the report have doubts about the modelling presented due to low quality input
elevation data”.
Optional additional information about
the hydraulic modelling.
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5.5.4 Damage Assessment Box
Figure 12 Screenshot of the Damage Assessment Box
The Damage Assessment relates to the damage caused by the flooding. Usually there is a relatively detailed section in the study devoted to the calculation of these
values. These can usually be found after the discussion of the modelling. Sometimes a separate report or volume specifically dealing with damage costs will include
this analysis. This information is often presented in tabular form. The List of Tables following the Table of Contents may help to locate the section relating to this data.
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Data Entry Guidelines November 2014
Table 7 Events Row - Damage Assessment Box fields and guidance
Field Name
Definition
Field Rules
Field Entry Guidance
Comments
Additional information about the damage assessment analysis.
Free text. Current character
limit of 1000.
Proper sentences else a short
note without a full stop.
Note the year of the estimate
i.e. $140,000 (2006 dollars).
Items read in the report that relate directly to the
accuracy of the assessment may be reported here
e.g.
“The damage in the area west of the river would
be less in practice because of the change in
building codes that were not included in this
modelling.”
Method(s)
The method (methodology or approach) used to develop the
damage assessment.
Damage Type(s)
The type of damage considered in the assessment.
Typically inundation depth only but if a study has
modelled velocity or other parameters the study
should be checked in detail to ascertain if this data
was used in the calculation of damage.
Building Type(s)
The broad classification of the dominant type of building
inundated for the modelled event.
Can usually be inferred from the text around the
calculations of Estimated Damage or in tables
found in those sections of the report.
Building Material Type(s) The broad classification of the dominant construction materials
for buildings estimated as damaged in the modelled or actual
event.
Do not fill this field out unless the details of
building materials were specifically taken into
account in the report during damage calculations.
Average Annual Damage Depending on its size (or severity), each flood will cause a
Recorded in Australian
($)
different amount of flood damage to a flood prone area. Average dollars.
annual damage (AAD) is the average damage per year that
would occur in a nominated development situation from flooding
over a very long period of time. If the damage associated with
various annual events is plotted against their probability of
occurrence, the AAD is equal to the area under the
consequence-probability curve. AAD provides a basis for
comparing the economic effectiveness of different management
measures, (i.e. their ability to reduce the AAD).
Remember to note the year of the estimate i.e.
$140,000 (2006 dollars) in the Comments section.
Year of Valuation
A year representing when the Dollar figures were current.
Sometimes this is stated explicitly (especially in
large studies spanning many years) in the flood
study itself, otherwise an appropriate value could
be the year the study was released.
Buildings with Water
The number of buildings that have water on the property for the
scenario modelled.
Data Entry Guidelines November 2014
A 4 digit year
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Field Name
Definition
Buildings Inundated
The number of buildings with water over the floor for the
scenario modelled.
Field Rules
Field Entry Guidance
Event Estimated cost ($) Estimate of the total cost of damages for the scenario modelled.
5.6 Mitigation Row
Figure 13 Screenshot of the Mitigation Tab.
The Mitigation Tab records information about mitigation strategies that have been recommended by, or undertaken in direct response to, the flood study.
Flood studies may include comparisons of various mitigation options that end in solid recommendations. However, sometimes that analysis is dealt with in a
separate report. When available that document should be attached to the flood study entry and used to fill in the recommended strategies. For example,
studies following the NSW State Government’s flood policy have this information separated from the Flood Study into a Floodplain Risk Management Study
(see ASFID 2842 as an example).
Only strategies that are unambiguously recommended in the document should be selected here. Sometimes it can be difficult to find strong recommendations
in amongst the many options for mitigation being considered. In the absence of a section titled Recommendations, look in the summary sections related to the
mitigation options for sentences similar to “Of all the strategies discussed here the following are cost effective and should be implemented…”.
Be careful of options that are found to be highly effective but too expensive to be recommended as these should not be selected under this tab e.g. “The
construction of the ~ levee was found to almost completely mitigate the worst areas of the flooding and would be built in an area of unoccupied land, however
due to the high cost and the presence of other cheaper mitigation options it is not suggested”. As with other sections, if “Other” is selected, the item must be
specified.
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Data Entry Guidelines November 2014
5.7 Review Page
Figure 14 Screenshot of Review Page.
The Review Page provides an overview of all data entered as a final check before submission for
quality assurance. Use this summary to check for spelling mistakes and to ensure that all the
information entered is correct and complete. Double check that you have attached the digital copy of
the flood study, (and any other relevant reports and figures). Also check that you can download and
open attachments from the submissions page.
When you are satisfied that the study is complete and accurate, click the “Submit” button.
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Glossary
Adapted From
*Glossary entries are sourced from 1 unless otherwise numbered.
1. Australian Emergency Management Handbook Series ‘Managing the floodplain: a guide to best
practice in flood risk management in Australia’, Australian Emergency Management
Institute, Australian Government Attorney-General’s Department, 2013 Second edition ISBN 9781-921152-33-7, pp. 159-169.
2. Armidale Dumaresq Council and Paterson Consulting (2005) ‘Armidale Flood Study’, Report for
The Armidale Dumaresq Council, pp. i-vii.
3. Sinclair Knight Merz (2009) ‘Shire of Boddington Floodplain Management Study. Flood Modelling
Report’, Report for The Shire of Boddington, pp. iii-iv.
4. Rowe, WD. (1990) ‘Perspective on Rare Events for Decision Making’, In: Proceedings of a
Conference on Risk Based Decision Making in Water Resources, Santa Barbara, California, 15-20
October 1989, American Society of Civil Engineers, (ASCE), pp. 1-15.
5. World Meteorological Organization (2009) Manual for Estimation of Probable Maximum
Precipitation, 3rd edition, WMO - No. 1045, Geneva, ISBN 978-92-63-11045-9
6. SCARM (2000) ‘Floodplain management in Australia: Best practice principles and guidelines’,
Agriculture and Resource Management Council of Australia and New Zealand, Standing
Committee on Agriculture and Resource Management, Report No. 73, CSIRO Publishing,
Collingwood, Victoria, ISBN 0643-06034-0, pp. 94-101.
Aerial Photogrammetry
Aerial photogrammetry uses aerial photographs to produce topographic maps of the earth's surface
and of features of the built environment.2
Annual exceedance probability (AEP)
The likelihood of the occurrence of a flood of a given or larger size occurring in any one year, usually
expressed as a percentage. For example, if a peak flood flow of 500 m 3/s has an AEP of 5%, it means
that there is a 5% chance (that is, a one-in-20 chance) of a flow of 500 m 3/s or larger occurring in any
one year (see also average recurrence interval, flood risk, likelihood of occurrence, probability).
Astronomical tide
The variation in sea level caused by the gravitational effects of (principally) the moon and sun. It
includes highest and lowest astronomical tides (HAT and LAT) occur when relative alignment and
distance of the sun and moon from the earth are ‘optimal’. Water levels approach to within 20 cm of
HAT and LAT twice per year around mid-summer and mid-winter ‘king tides’.
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Australian height datum (AHD)
A common national survey height datum as a reference level for defining reduced levels; 0.0 m AHD
corresponds approximately to sea level.
Average annual damage (AAD)
Depending on its size (or severity), each flood will cause a different amount of flood damage to a
flood-prone area. AAD is the average damage per year that would occur in a nominated development
situation from flooding over a very long period of time. If the damage associated with various annual
events is plotted against their probability of occurrence, the AAD is equal to the area under the
consequence–probability curve. AAD provides a basis for comparing the economic effectiveness of
different management measures (i.e. their ability to reduce the AAD).
Average recurrence interval (ARI)
A statistical estimate of the average number of years between the occurrence of a flood of a given size
or larger than the selected event. For example, floods with a flow as great as or greater than the 20year ARI (5% AEP) flood event will occur, on average, once every 20 years. ARI is another way of
expressing the likelihood of occurrence of a flood event (see also annual exceedance probability).
Bathymetry
The configuration of the bed of a water body, as measured by depth contours.6
Cadastre
Legal lot boundaries.2
Catchment
The area of land draining to a particular site. It is related to a specific location, and includes the
catchment of the main waterway as well as any tributary streams.
Catchment flooding
Flooding due to prolonged or intense rainfall (e.g. severe thunderstorms, monsoonal rains in the
tropics, tropical cyclones). Types of catchment flooding include riverine, local overland and
groundwater flooding.
Chance
The likelihood of something happening that will have beneficial consequences (e.g. the chance of a
win in a lottery). Chance is often thought of as the ‘upside of a gamble’ (Rowe 1990 4) (see also risk).
Critical Storm Duration
The duration of the storm event of nominated severity (e.g. the 2% AEP flood) that produces the
largest flood discharge at the location of interest. Critical storm duration depends upon catchment
size, topography and land use and on the temporal pattern of rainfall. 6
Coastal flooding
Flooding due to tidal or storm-driven coastal events, including storm surges in lower coastal
waterways. This can be exacerbated by wind-wave generation from storm events.
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Consent authority
The authority or agency with the legislative power to determine the outcome of development and
building applications.
Consequence
The outcome of an event or situation affecting objectives, expressed qualitatively or quantitatively.
Consequences can be adverse (e.g. death or injury to people, damage to property and disruption of
the community) or beneficial.
Defined flood event (DFE)
The flood event selected for the management of flood hazard to new development. This is generally
determined in floodplain management studies and incorporated in floodplain management plans.
Selection of DFEs should be based on an understanding of flood behaviour, and the associated
likelihood and consequences of flooding. It should also take into account the social, economic,
environmental and cultural consequences associated with floods of different severities. Different DFEs
may be chosen for the basis for reducing flood risk to different types of development. DFEs do not
define the extent of the floodplain, which is defined by the PMF (see also design flood, floodplain and
probable maximum flood).
Design flood
The flood event selected for the treatment of existing risk through the implementation of structural
mitigation works such as levees. It is the flood event for which the impacts on the community are
designed to be limited by the mitigation work. For example, a levee may be designed to exclude a 2%
AEP flood, which means that floods rarer than this may breech the structure and impact upon the
protected area. In this case, the 2% AEP flood would not equate to the crest level of the levee,
because this generally has a freeboard allowance, but it may be the level of the spillway to allow for
controlled levee overtopping (see also annual exceedance probability, defined flood event, floodplain,
freeboard and probable maximum flood).
Development
Development may be defined in jurisdictional legislation or regulation. This may include erecting a
building or carrying out of work, including the placement of fill; the use of land, or a building or work; or
the subdivision of land.
Infill development refers to the development of vacant blocks of land within an existing subdivision that
are generally surrounded by developed properties and is permissible under the current zoning of the
land. Conditions such as minimum floor levels may be imposed on infill development.
New development is intensification of use with development of a completely different nature to that
associated with the former land use or zoning (e.g. the urban subdivision of an area previously used
for rural purposes). New developments generally involve rezoning, and associated consents and
approvals. It may require major extensions of existing urban services, such as roads, water supply,
sewerage and electric power.
Redevelopment refers to rebuilding in an existing developed area. For example, as urban areas age, it
may become necessary to demolish and reconstruct buildings on a relatively large scale.
Redevelopment generally does not require either rezoning or major extensions to urban services.
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Ecologically sustainable development
Using, conserving and improving natural resources so that ecological processes on which life depends
are maintained, and the total quality of life – now and in the future – can be maintained or increased.
Effective warning time
The effective warning time available to a flood-prone community is equal to the time between the
delivery of an official warning to prepare for imminent flooding and the loss of evacuation routes due to
flooding. The effective warning time is typically used for people to self-evacuate, to move farm
equipment, move stock, raise furniture, and transport their possessions.
Existing flood risk
The risk a community is exposed to as a result of its location on the floodplain.
Flash flood
Flood that is sudden and unexpected. It is often caused by sudden local or nearby heavy rainfall. It is
generally not possible to issue detailed flood warnings for flash flooding. However, generalised
warnings may be possible. It is often defined as flooding that peaks within six hours of the causative
rain.
Flood
Flooding is a natural phenomenon that occurs when water covers land that is normally dry. It may
result from coastal or catchment flooding, or a combination of both (see also catchment flooding and
coastal flooding).
Flood awareness
An appreciation of the likely effects of flooding, and a knowledge of the relevant flood warning,
response and evacuation procedures. In communities with a high degree of flood awareness, the
response to flood warnings is prompt and effective. In communities with a low degree of flood
awareness, flood warnings are liable to be ignored or misunderstood, and residents are often
confused about what they should do, when to evacuate, what to take with them and where it should be
taken.
Flood damage
The tangible (direct and indirect) and intangible costs (financial, opportunity costs, clean-up) of
flooding. Tangible costs are quantified in monetary terms (e.g. damage to goods and possessions,
loss of income or services in the flood aftermath). Intangible damages are difficult to quantify in
monetary terms and include the increased levels of physical, emotional and psychological health
problems suffered by flood-affected people that are attributed to a flooding episode.
Flood education
Education that raises awareness of the flood problem, to help individuals understand how to manage
themselves and their property in response to flood warnings and in a flood event. It invokes a state of
flood readiness.
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Flood emergency management plan
A step-by-step sequence of previously agreed roles, responsibilities, functions, actions and management
arrangements for the conduct of a single or series of connected emergency operations. The objective is
to ensure a coordinated response by all agencies having responsibilities and functions in emergencies.
Flood emergency management
Emergency management is a range of measures to manage risks to communities and the
environment. In the flood context, it may include measures to prevent, prepare for, respond to and
recover from flooding.
Flood frequency analysis
A statistical analysis to determine the relationship between peak discharge and the likelihood of the
occurrence of the peak discharge. This is undertaken based on recorded historical data. 3
Flood fringe areas
The part of the floodplain where development could be permitted, provided the development is
compatible with flood hazard and appropriate building measures to provide an adequate level of flood
protection to the development. This is the remaining area affected by flooding after flow conveyance
paths and flood storage areas have been defined for a particular event (see also flow conveyance
areas and flood storage areas).
Flood hazard
Potential loss of life, injury and economic loss caused by future flood events. The degree of hazard
varies with the severity of flooding and is affected by flood behaviour (extent, depth, velocity, isolation,
rate of rise of floodwaters, duration), topography and emergency management.
Floodplain
An area of land that is subject to inundation by floods up to and including the probable maximum flood
event – that is, flood-prone land.
Floodplain management entity (FME)
The authority or agency with the primary responsibility for directly managing flood risk at a local level.
Floodplain management plan
A management plan developed in accordance with the principles and guidelines in this handbook,
usually includes both written and diagrammatic information describing how particular areas of floodprone land are to be used and managed to achieve defined objectives. It outlines the recommended
ways to manage the flood risk associated with the use of the floodplain for various purposes. It
represents the considered opinion of the local community and the floodplain management entity on
how best to manage the floodplain, including consideration of flood risk in strategic land-use planning
to facilitate development of the community.
It fosters flood warning, response, evacuation, clean-up and recovery in the onset and aftermath of a
flood, and suggests an organisational structure for the integrated management for existing, future and
residual flood risks. Plans need to be reviewed regularly to assess progress and to consider the
consequences of any changed circumstances that have arisen since the last review.
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Flood planning area
The area of land below the flood planning level, and is thus subject to flood-related development
controls.
Flood planning level (FPL)
The FPL is a combination of the defined flood levels (derived from significant historical flood events or
floods of specific annual exceedance probabilities) and freeboards selected for floodplain
management purposes, as determined in management studies and incorporated in management
plans.
Flood-prone land
Land susceptible to flooding by the probably maximum flood event. Flood-prone land is synonymous
with the floodplain. Floodplain management plans should encompass all flood-prone land rather than
being restricted to areas affected by defined flood events.
Flood proofing of buildings
A combination of measures incorporated in the design, construction and alteration of individual
buildings or structures that are subject to flooding, to reduce structural damage and potentially, in
some cases, reduce contents damage.
Flood readiness
An ability to react within the effective warning time (see also flood awareness and flood education).
Flood risk
The potential risk of flooding to people, their social setting, and their built and natural environment.
The degree of risk varies with circumstances across the full range of floods. Flood risk is divided into
three types – existing, future and residual.
Flood severity
A qualitative indication of the ‘size’ of a flood and its hazard potential. Severity varies inversely with
likelihood of occurrence (i.e. the greater the likelihood of occurrence, the more frequently an event will
occur, but the less severe it will be). Reference is often made to major, moderate and minor flooding
(see also minor, moderate and major flooding).
Flood storage areas
The parts of the floodplain that are important for temporary storage of floodwaters during a flood
passage. The extent and behaviour of flood storage areas may change with flood severity, and loss of
flood storage can increase the severity of flood impacts by reducing natural flood attenuation. Hence,
it is necessary to investigate a range of flood sizes before defining flood storage areas (see also flow
conveyance areas and flood fringe areas).
Flood study
A comprehensive technical investigation of flood behaviour. It defines the nature of flood hazard across
the floodplain by providing information on the extent, level and velocity of floodwaters, and on the
distribution of flood flows. The flood study forms the basis for subsequent management studies and
needs to take into account a full range of flood events up to and including the probable maximum flood.
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Flow
The rate of flow of water measured in volume per unit time – for example, cubic metres per second
(m3/s). Flow is different from the speed or velocity of flow, which is a measure of how fast the water is
moving for example, metres per second (m/s).
Flow conveyance areas
Those areas of the floodplain where a significant flow of water occurs during floods. They are often
aligned with naturally defined channels. Flow conveyance paths are areas that, even if only partially
blocked, would cause a significant redistribution of flood flow or a significant increase in flood levels.
They are often, but not necessarily, areas of deeper flow or areas where higher velocities occur, and
can also include areas where significant storage of floodwater occurs.
Each flood has a flow conveyance area, and the extent and flood behaviour within flow conveyance
areas may change with flood severity. This is because areas that are benign for small floods may
experience much greater and more hazardous flows during larger floods (see also flood fringe areas
and flood storage areas).
Freeboard
The height above the DFE or design flood used, in consideration of local and design factors, to
provide reasonable certainty that the risk exposure selected in deciding on a particular DFE or design
flood is actually provided. It is a factor of safety typically used in relation to the setting of floor levels,
levee crest levels and so on. Freeboard compensates for a range of factors, including wave action,
localised hydraulic behaviour and levee settlement, all of which increase water levels or reduce the
level of protection provided by levees. Freeboard should not be relied upon to provide protection for
flood events larger than the relevant defined flood event of a design flood. Freeboard is included in the
flood planning level and therefore used in the derivation of the flood planning area (see also defined
flood event, design flood, flood planning area and flood planning level).
Frequency
The measure of likelihood expressed as the number of occurrences of a specified event in a given
time. For example, the frequency of occurrence of a 20% annual exceedance probability or five-year
average recurrence interval flood event is once every five years on average (see also annual
exceedance probability, annual recurrence interval, likelihood and probability).
Future flood risk
The risk that new development within a community is exposed to as a result of developing on the
floodplain.
Gauge height
The height of a flood level at a particular gauge site related to a specified datum. The datum may or
may not be the AHD (see also Australian height datum).
Geographical information systems (GIS)
A system of software and procedures designed to support the management, manipulation, analysis
and display of spatially referenced data. 2
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Habitable room
In a residential situation, a living or working area, such as a lounge room, dining room, rumpus room,
kitchen, bedroom or workroom. In an industrial or commercial situation, it refers to an area used for
offices or to store valuable possessions susceptible to flood damage in the event of a flood.
Hazard
A source of potential harm or a situation with a potential to cause loss. In relation to this handbook, the
hazard is flooding, which has the potential to cause damage to the community.
Hydraulic analysis
The study of water flow in waterways; in particular, the evaluation of flow parameters such as water
level, extent and velocity.
Hydrograph
A graph that shows how the flow or stage (flood level) at any particular location varies with time during
a flood.
Hydrologic analysis
The study of the rainfall and runoff process, including the evaluation of peak flows, flow volumes and
the derivation of hydrographs for a range of floods.
Impervious
A surface or area within the catchment where the majority of the rainfall becomes runoff e.g. roads,
car parks and roofs etc.3
Intolerable risk
A risk that, following understanding of the likelihood and consequences of flooding, is so high that it
requires consideration of implementation of treatments or actions to improve understanding, avoid,
transfer or reduce the risk.
Life-cycle costing
All of the costs associated with the project from the cradle to the grave. This usually includes
investigation, design, construction, monitoring, maintenance, asset and performance management
and, in some cases, decommissioning of a management measure.
Likelihood
A qualitative description of probability and frequency (see also frequency and probability).
Likelihood of occurrence
The likelihood that a specified event will occur. (With respect to flooding, see also annual exceedance
probability and average recurrence interval).
Local overland flooding
Inundation by local runoff on its way to a waterway, rather than overbank flow from a stream, river,
estuary, lake or dam. Can be considered synonymous with stormwater flooding.
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Loss
Any negative consequence or adverse effect, financial or otherwise.
Manning’s Roughness Coefficient (n)
Variable used in mathematical computations to represent the relative roughness of ground terrain.2
Mathematical and computer models
The mathematical representation of the physical processes involved in runoff generation and stream
flow. These models are often run on computers due to the complexity of the mathematical
relationships between runoff, stream flow and the distribution of flows across the floodplain.
Merit approach
The merit approach weighs social, economic, ecological and cultural impacts of land-use options for
different flood-prone areas, together with flood damage, hazard and behaviour implications, and
environmental protection and wellbeing of rivers and floodplains. This approach operates at two levels.
At the strategic level, it allows for the consideration of flood hazard and associated social, economic,
ecological and cultural issues in formulating statutory planning instruments, and development control
plans and policies. At a site-specific level, it involves consideration of the best way of developing land
in consideration of the zonings in a statutory planning instruments, and development control plans and
policies.
Minor, moderate and major flooding
These terms are often used in flood warnings to give a general indication of the types of problems
expected with a flood:

Minor flooding causes inconvenience such as minor roads closures and the submergence of lowlevel bridges. The lower limit of this class of flooding on the reference gauge may be the initial
flood level at which landholders and townspeople begin to be flooded.

Moderate flooding refers to the inundation of low-lying areas, which requires stock to be removed
and/or some houses to be evacuated. Main traffic routes may be covered.

Major flooding refers to when appreciable urban areas and/or extensive rural areas are flooded.
Properties, villages and towns can be isolated.
Mitigation
Permanent or temporary measures taken in advance of a flood aimed at reducing its impacts.
Peak flow
The maximum flow occurring during a flood event past a given point in the river system (see also flow
and hydrograph).
Pluviograph
An instrument that automatically records the amount of rainfall as a function of time normally at subdaily interval.3
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Probability
A statistical measure of the expected chance of flooding. It is the likelihood of a specific outcome, as
measured by the ratio of specific outcomes to the total number of possible outcomes. Probability is
expressed as a number between zero and unity, zero indicating an impossible outcome and unity
indicating an outcome that is certain. Probabilities are commonly expressed in terms of percentage.
For example, the probability of ‘throwing a six’ on a single roll of a die is one in six, or 0.167 or 16.7%
(see also annual exceedance probability).
Probable maximum flood (PMF)
The PMF is the largest flood that could conceivably occur at a particular location, usually estimated
from PMP and, where applicable, snow melt, coupled with the worst flood-producing catchment
conditions. Generally, it is not physically or economically possible to provide complete protection
against this event. The PMF defines the extent of flood-prone land – that is, the floodplain. The extent,
nature and potential consequences of flooding associated with a range of events rarer than the flood
used for designing mitigation works and controlling development, up to and including the PMF event,
should be addressed in a floodplain risk management study.
Probable maximum precipitation (PMP)
The PMP is the greatest depth of precipitation for a given duration meteorologically possible over 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 (WMO 1986). It is the primary input to probable maximum flood
estimation.5
Rainfall intensity
The rate at which rain falls, typically measured in millimetres per hour (mm/h). Rainfall intensity varies
throughout a storm in accordance with the temporal pattern of the storm (see also temporal pattern).
Residual flood risk
The risk a community is exposed to that is not being remedied through established risk treatment
processes. In simple terms, for a community, it is the total risk to that community, less any measure in
place to reduce that risk.
The risk a community is exposed to after treatment measures have been implemented. For a town
protected by a levee, the residual flood risk is the consequences of the levee being overtopped by
floods larger than the design flood. For an area where flood risk is managed by land-use planning
controls, the residual flood risk is the risk associated with the consequences of floods larger than the
DFE on the community.
Risk
‘The chance of something happening that will have an impact on objectives’ (ISO 13000:2009). It is
measured in terms of consequences and likelihood. Risk is based upon the consideration of the
consequences of the full range of flood behaviour on communities and their social settings, and the
natural and built environment. Risk is often thought of as the "downside of a gamble" (Rowe 1990 4)
(see also likelihood and consequence).
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Risk analysis
The systematic use of available information to determine how often specified (flood) events occur and
the magnitude of their likely consequences. Flood risk analysis is normally undertaken as part of a
floodplain management study, and involves an assessment of flood levels and hazard associated with
a range of flood events (see also flood study).
Risk management
The systematic application of management policies, procedures and practices to the tasks of
identifying, analysing, assessing, treating and monitoring flood risk. Flood risk management is
undertaken as part of a floodplain management plan. The floodplain management plan reflects the
adopted means of managing flood risk (see also floodplain management plan).
Riverine flooding
Inundation of normally dry land occurring when water overflows the natural or artificial banks of a
stream, river, estuary, lake or dam. Riverine flooding generally excludes watercourses constructed
with pipes or artificial channels considered as stormwater channels.
Runoff
The amount of rainfall that drains into the surface drainage network to become stream flow; also
known as rainfall excess.
Stage
Equivalent to water level. Both stage and water level are measured with reference to a specified
datum (e.g. the Australian height datum).
Storm surge
The increases in coastal water levels above predicted astronomical tide level (i.e. tidal anomaly)
resulting from a range of location dependent factors including the inverted barometer effect, wind and
wave set-up and astronomical tidal waves, together with any other factors that increase tidal water
level (see also astronomical tide, wind set-up and wave set-up).
Stormwater flooding
Is inundation by local runoff caused by heavier than usual rainfall. It can be caused by local runoff
exceeding the capacity of an urban stormwater drainage systems, flow overland on the way to
waterways or by the backwater effects of mainstream flooding causing urban stormwater drainage
systems to overflow (see also local overland flooding).
Temporal pattern
The variation of rainfall intensity with time during a rainfall event.
Tidal anomaly
The difference between recorded storm surge levels and predicted astronomical tide level.
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Treatment options
The measures that might be feasible for the treatment of existing, future and residual flood risk at
particular locations within the floodplain. Preparation of a treatment plan requires a detailed evaluation
of floodplain management options (see also floodplain management plan).
Velocity of floodwater
The speed of floodwaters, measured in metres per second (m/s).
Vulnerability
The degree of susceptibility and resilience of a community, its social setting, and the natural and built
environments to flood hazards. Vulnerability is assessed in terms of ability of the community and
environment to anticipate, cope and recover from flood events. Flood awareness is an important
indicator of vulnerability (see also flood awareness).
Wave set-up
The increase in water levels in coastal waters (within the breaker zone) caused by waves transporting
water shorewards. The zone of wave set-up against the shore is balanced by a zone of wave ‘setdown’ (i.e. reduced water levels) seawards of the breaker zone. Wave set-ups of 2–4 m could occur
during tropical cyclones.
Wind set-up
The increase in water levels in coastal waters caused by the wind driving the water shorewards and
‘piling it up’ against the shore. Wind set-up can be as high as 10 m in an extreme case, and often
exceeds 2–3 m in typical tropical cyclones.
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