National Floodplain Mapping Assessment - Final Report

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National Floodplain Mapping
Assessment - Final Report
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National Floodplain Mapping
Assessment
Final Report
June 2014

National Floodplain Management Framework Page i
Public Safety Canada
Executive Summary
Canada has witnessed a notable increase in flooding over the past decade, with total damages
exceeding $10 billion. As part of Public Safety Canada’s mandate to mitigate losses resulting
from natural events, a National Floodplain Management Framework has been prepared as an
initial step in reducing flood risk across Canada.
Starting in 1975 the Flood Damage Reduction Program (FDRP), an initiative of Environment
Canada, was implemented in collaboration with the provincial and territorial governments and
ran until 1996. This very comprehensive initiative led to the thousands of kilometres of flood
hazard mapping across Canada. The FDRP included the development of a comprehensive set of
guidelines and standards that guided the program.
The National Floodplain Management Framework, summarized herein, builds upon the
Emergency Management Framework, the National Disaster Mitigation Strategy and the original
Flood Damage Reduction Program.
The National Floodplain Management Framework includes two key components: Flood Hazard
Mapping and the Flood Risk Database. It will serve as a key document that will help to reduce
and mitigate flood risk across Canada.
The National Floodplain Management Framework that is presented in this document identifies:
• The type and extent of information that must be collected and managed;
• The key standards and guidelines that will apply to the development of Flood Hazard Maps
and the Flood Risk Database.;
• The anticipated cost of updating and preparing new hazard maps, as required, and the
compilation of data for the flood risk data base; and
• A list of initiatives to be completed as part of implementation.
A number of Guiding Principles have been identified to help inform the National Floodplain
Management Framework and its ultimate implementation. Adherence to these principles will
aid significantly in developing the fundamental tools necessary to effectively manage and
mitigate flood risk across Canada.
• Technical Accuracy
• Effective in Assessing and Managing Risk
• Accessibility to the User
• Current

National Floodplain Management Framework Page ii
The first step in developing the National Floodplain Management Framework included review
of practices in seven countries other than Canada, review of current provincial and territorial
practices, and input from subject matter experts.
The international review also provides a point of reference between current practices in
Canada and those across the globe. The countries reviewed included the United Kingdom (UK),
Australia, the United States of America (USA), France, Germany, Switzerland and New Zealand.
Following from the international review, a number of key practices and standards were
identified for consideration in the development of the National Floodplain Management
Framework for Canada.
The flood plain mapping practices, key standards, and unique challenges for each province and
territory in Canada and a compilation of comments and recommendations from a wide range of
subject matter experts were also summarized. All of the information will help to inform the
National Floodplain Management Framework.
The key comments received from across Canada are summarized below.
Technical Accuracy
1. The fact that there is a high degree of uncertainty in all of the steps leading to estimation of
flood risk should be documented and included as part of the presentation of flood risk.
2. Additional streamflow gauging would help with accuracy, particularly in ungauged
watersheds.
3. Standard methods for relating flooding to damages should be updated across Canada.
4. There should be more formal procedures available to complete all steps of the mapping
process.
5. More importance should be placed on both calibration and on-going updates/verification.
Effective in Assessing and Managing Risk
6. There should be a National Vision and set of standards that would apply across Canada.
7. Floodplain management should move beyond hazard mapping to consider risk to
communities, industry and agriculture.
8. Mapping should be extended along more rivers, particularly through urban areas.
9. Events more severe than the 1:100 year event should be considered in hazard mapping and
flood risk assessment; particularly when one considers both the degree of uncertainty
associated with the estimates and that statistically a 1:100 year event has a 65 percent
chance of occurring in a 100 year period.

National Floodplain Management Framework Page iii
Accessibility to the User
10. The public should have much better access to flood risk information.
Current
11. Across much of Canada there is a need for updated floodplain mapping.
The development of floodplain mapping, as it is understood today, began in approximately
1975. Currently mapping is available along some 28,000 km of rivers and streams across
Canada. Most of the mapping was initially developed between 1975 and 1996 through the
federal-provincial Flood Damage Reduction Program (FDRP). However with updates and
additional mapping that have been completed since FDRP, approximately half of the existing
mapping was developed after 1996.
The extent of mapping in each province and territory is generally proportional to the
population. Of the total, 59 percent of existing floodplain mapping is in Ontario, 21 percent is in
Québec, and 10 percent is in British Columbia. The remaining 10 percent is distributed across
the other provinces and territories. This is because the focus has always been on preparing
mapping for the more populated areas.
Overall approximately 35 percent of the mapping is through urban areas. However the ratio of
mapping that is in urban areas varies widely, from a low of 14 percent in British Columbia to a
midrange of 49 percent in Alberta to a high of 75 percent in Québec.
Although the median age of all mapping in Canada is 18 years (1996), there is also a fair
variability in mapping age. The median age of all mapping in Alberta, Québec and Ontario is
approximately 10 years old, while it is in excess of 20 years old in the remaining jurisdictions.
The comparison of current mapping to the proposed mapping standards is based on the
following key standards:
• Base Mapping
• Regulatory Event for Flood Hazard Mapping
• Flood Risk Database
• Age of mapping
• Climate Change Adaptation
It is concluded that existing flood plain mapping across Canada does not meet the majority of
the standards proposed as part of the National Floodplain Management Framework. This
conclusion does not infer that existing mapping is inadequate, but rather that the proposed
standards represent a step forward in defining how floodplains should be mapped and how
flood risk should be documented.

National Floodplain Management Framework Page iv
As a next step it is recommended that a Risk Assessment be completed to better identify and
understand the areas of highest risk. Results of the Risk Assessment would then be used in
establishing priorities for updating mapping in accordance with the proposed standards
The cost of developing updated Hazard Maps and creating the Flood Risk databases is based on
the costs associated with:
1. Preparing base mapping.
2. Completing the hydrologic studies.
3. Completing detailed hydraulic surveys of infrastructure and buildings in the floodplain.
4. Preparing the hazard mapping.
5. Populating the database.
Actual costs will vary widely depending on complexity, width of the floodplain, number of
buildings, density of infrastructure, and approach to calculating flow rates. On average it is
expected that the cost of completing all steps would range from $7,500/km in a rural setting to
$10,500/km in an urban setting assuming a 1-D hydraulic model is employed. For 2-D hydraulic
modelling the cost would increase to $50,000/km due to greater complexity.
The cost of updating existing mapping and creating an additional 15,300 km of mapping is
approximately $365 million. The additional 15,300 km should be sufficient to ensure that
mapping is available for 90-95 percent of the population in flood prone areas. Depending on
the results of the Risk Assessment and the review of new areas to be mapped, it is anticipated
that this cost estimate could change.
The National Floodplain Management Framework will include both Performance Standards and
Technical Standards. The Performance Standards refer to the key standards that define risk.
Three levels of standards are proposed: High, Medium and Low.
• High: Apply to all urban areas and rural areas that are protected by diking
• Medium: Apply to remaining rural areas that include settlements and agricultural lands
• Low: Apply to unpopulated areas, and may be used to guide the development of
infrastructure
Table B1 in Appendix B details the proposed Performance Standards.
The Technical Standards refer to the tolerance requirements that are to be adhered to in
developing the hazard mapping and the flood risk data base. Table B2 (Appendix B) presents
the key technical standards although it is not exhaustive. Many more standards will be
incorporated into the guidelines as part of the various procedures that will be documented. In
fact, many of the Technical Standards listed herein may also be adjusted at that time.

National Floodplain Management Framework Page v
There are a several initiatives that are recommended to be completed prior to embarking on
the update of the flood hazard mapping and the development of the flood risk database. These
initiatives could be undertaken simultaneously over a period of 12 to 15 months.
• Complete a National Risk Assessment to help establish mapping priorities.
• Develop the Guidelines and refine the Technical Standards.
• Develop a framework for the Flood Risk Database.
• Determine the delivery model for preparing mapping and the database.
• Prepare Federal-Provincial/Territorial Agreements.

National Floodplain Management Framework Page vi
Table of Contents
1.0 Introduction ...................................................................................................................................... 1
2.0 Overview of the National Floodplain Management Framework ...................................................... 2
3.0 Approach to Developing the National Floodplain Management Framework .................................. 4
3.1 International Review ........................................................................................................................... 4
3.2 Summary of Key Practices ................................................................................................................. 14
3.3 Canadian Review ............................................................................................................................... 16
4.0 Expert Comments............................................................................................................................ 29
5.0 Status of Floodplain Management in Canada ................................................................................. 30
6.0 Comparison of Existing Mapping to Proposed Standards .............................................................. 33
7.0 The Proposed National Floodplain Management Framework ........................................................ 39
8.0 Initiatives and Next Steps ............................................................................................................... 45
Appendices
Appendix A – Floodplain Mapping Background
Appendix B - Performance Standards and Technical Standards

National Floodplain Management Framework Page 1
1.0 Introduction
Canada has witnessed a notable increase in flooding over the past decade, with total damages
exceeding $10 billion. As part of Public Safety Canada’s mandate to mitigate losses resulting
from natural events, a National Floodplain Management Framework has been prepared as an
initial step in reducing flood risk across Canada. The National Floodplain Management
Framework specifically presents the standards and guidelines that will be applied to the
updating of Flood Hazard Maps and the development of a National Flood Risk Database.
Recent Flooding in Canada
Since 2004, the most notable Riverine1 flood events in
Canada occurred in Alberta in 2005 and 2013, and
Manitoba in 2009 and 2011. In addition, many central
Canadian cities experienced considerable damage due to
Urban Flooding2 associated with intense summer storms.
Key examples include Peterborough in 2004, Hamilton on
several occasions including 2005 and 2012, Montreal in
2011, and Toronto in 2005 and 2013.
The last comparable period was 1948 to 1954 when three catastrophic flood events occurred;
the Fraser River along the lower mainland of British Colombia (1948), the Red River through
Winnipeg (1950), and the Humber
River through Toronto and points
northwest (1954). The total
damage of these events totaled
$17.5 billion3. These three flood
events led to significant investment
in flood mitigation works and the
development of policies to guide
development in flood prone areas.
Public Safety Canada Mandate for Flood Mitigation
Public Safety Canada is the lead federal Agency responsible for disaster mitigation in Canada.
Two notable initiatives include the Emergency Management Framework (EMF) and the National
Disaster Mitigation Strategy (NDMS).
1 Riverine Flooding: flooding associated with a river or watercourse overtopping its banks.
2 Urban Flooding: flooding associated with municipal infrastructure (sewers and streets) exceeding their capacity to convey
runoff.
3 Source: Making Flood Insurable for Canadian Homeowners, A Discussion Paper, Swiss Re, November 2010.

The Emergency Management Framework (EMF) is a joint initiative of federal, provincial and
territorial governments that focuses on saving lives and reducing economic damage associated
catastrophic loss events. The framework is built on four components including: prevention and
mitigation, preparedness, response and recovery.
The National Disaster Mitigation Strategy (NDMS) is also a joint initiative of federal, provincial
and territorial governments with an initial focus on reducing risk associated with natural
hazards. Although natural hazards encompass events such as fires and droughts, flooding is of
primary concern in terms of loss of life and property.
Floodplain Mapping Background
Appendix A includes an overview of floodplain mapping that may be helpful to the reader in
terms of understanding the content and context of this report.
2.0 Overview of the National Floodplain Management Framework
Starting in 1975 the Flood Damage Reduction Program (FDRP), an initiative of Environment
Canada was implemented in collaboration with the provincial and territorial governments and
ran until 1996. This very comprehensive initiative led to the thousands of kilometres of flood
hazard mapping across Canada. The FDRP included the development of a comprehensive set of
guidelines and standards that guided the program.
The National Floodplain Management Framework, summarized herein, builds upon the
Emergency Management Framework, the National Disaster Mitigation Strategy and the original
Flood Damage Reduction Program.
The National Floodplain Management Framework includes two key components: Flood Hazard
Mapping and the Flood Risk Database. It will serve as a key document that will help to reduce
and mitigate flood risk across Canada.
In this context Flood Hazard Mapping refers to traditional flood plain maps that delineate the
extent of flooding for a Regulatory Flood4. However, for infrastructure that is in the floodplain
Flood Hazard Mapping does generally not provide an indication of the likelihood or
consequence of flooding.
A Flood Risk Database refers to the information that must accompany the Flood Hazard
Mapping in order to quantify flood risk (likelihood and consequence of flooding). As an example
the database would include an inventory of buildings in the floodplain including the probability
that the building will flood and possibly the approximate damages associated with the flood.
4
A Regulatory Flood is the flood event that is used to define the floodplain and establish policies specific to development and
redevelopment in the floodplain. Across Canada the minimum Regulatory Flood is the 1-100-year flood, although in many
jurisdictions a more severe event is used for regulatory purposes.

The National Floodplain Management Framework addresses both traditional
Flood Hazard Mapping and a Flood Risk Database that will help to quantify the
likelihood and consequence of flooding.
The National Floodplain Management Framework that is presented in this document identifies:
• The type and extent of information that must be collected and managed;
• The key standards and guidelines that will apply to the development of Flood Hazard Maps
and the Flood Risk Database.;
• The anticipated cost of updating and preparing new hazard maps, as required, and the
compilation of data for the flood risk data base; and
• A list of initiatives to be completed as part of implementation.
Updated Flood Hazard Mapping will provide a clear and consistent understanding of the extent
of flooding across Canada. The Flood Risk Data Base will provide and organize the data
necessary to understand and manage flood risk.
Vision and Guiding Principles
A number of Guiding Principles have been identified to help inform the National Floodplain
Management Framework and its ultimate implementation. Adherence to these principles will
aid significantly in developing the fundamental tools necessary to effectively manage and
mitigate flood risk across Canada.
Technical Accuracy
Two broad technical factors define the accuracy of information that is needed to assess the
likelihood and consequence of flooding. These include hydrotechnical processes and geospatial
information. Among others, hydrotechnical processes include hydrology (flow rates), wave
action, and hydraulics (flood elevations). Geospatial information includes topographic mapping
and infrastructure details. Each of these plays an important role in the development of flood
hazard mapping and a flood risk database.
Implementation standards and guidelines must provide the assurance that all flood risk
assessments are as accurate and consistent as is practical. As such the implementation
standards and guidelines must address allowable tolerances, methodologies, documentation,
and quality control.

Fundamentally flood hazard mapping and the flood risk database must be comprehensive
enough that they can be used effectively in assessing and managing risk. This means that the
information on the mapping or in the database must address all aspects of risk specific to
infrastructure, industry and commerce, and communities.
The hazard mapping and flood risk data base must be equally available to potential users in
government, industry and the affected communities.
Current
The National Floodplain Management Framework must focus on the development of a dynamic
database that can be continually updated to reflect changes in available data, land use, and
climate change. Furthermore sufficient flexibility should be built in such that advances in the
state-of—the–art can be used to constantly improve accuracy, effectiveness and accessibility.
3.0 Approach to Developing the National Floodplain Management Framework
The first step in developing the National Floodplain Management Framework included review
of practices in seven countries other than Canada, review of current provincial and territorial
practices, and input from subject matter experts. Information derived from these sources then
helped to formulate the proposed approach. All of the collected information is presented in the
background report, Review of International and National Flood Mapping Practices, May 2014,
prepared in support of the National Floodplain Management Framework.
3.1 International Review
The first step in developing the National Floodplain Management Framework was to review
floodplain mapping practices from seven countries other than Canada. The objective of the
review was to understand current international practices with a view to identifying those
practices that could be incorporated into future Canadian practices. The international review
also provides a point of reference between current practices in Canada and those across the
globe. The countries reviewed included the United Kingdom (UK), Australia, the United States
of America (USA), France, Germany, Switzerland and New Zealand.
To guide the collection of the data on international practices we first prepared a template that
would ensure consistency in the approach to data collection. The template was structured to
include the following key components:

• General - recent initiatives related to updating floodplain mapping.
• Meteorology and Hydrology - methods used to calculate rainfall, snow melt and flow
rates that are used for floodplain mapping.
• Hydrotechnical - methods used to estimate storm surges and waves, as well as flood
elevations at any point along a river.
• Governance - responsibility of different government levels as well as policies related to
development in a floodplain.
• Flood Risk Assessment and Mapping - development of base mapping and the types of
information that are included on floodplain maps.
• Database - type of information that is collected and stored in a database.
• Access – the accessibility of the flood hazard mapping and the flood risk database.
Although the template was used as a guide, this did not preclude the collection of additional
information that would help to understand international floodplain mapping practices.
As noted, details of the findings regarding each country are provided in the background
document. The key findings for each country are provided below.
United Kingdom
European Union Requirements
The European Union’s Directive 2007/60/EC requires Member States to “….assess if all water
courses and coast lines are at risk from flooding, to map the flood extent and assets and
humans at risk in these areas and to take adequate and coordinated measures to reduce this
flood risk. This Directive also reinforces the rights of the public to access this information and to
have a say in the planning process….. The Directive requires Member States to first carry out a
preliminary assessment by 2011 to identify the river basins and associated coastal areas at risk
of flooding. For such zones they would then need to draw up flood risk maps by 2013 and
establish flood risk management plans focused on prevention, protection and preparedness by
2015. The Directive applies to inland waters as well as all coastal waters across the whole
territory of the EU.” 5
Related to the Directive, the European Exchange Circle on Flood Mapping (EXCIMAP) was
formed to gather all existing experiences and know-how in Europe and to improve flood
mapping practices. An outcome from EXCIMAP was to establish a guide to give an overview of
the existing good practices for flood mapping in Europe. Nearly 40 representatives from 24
countries or organizations participated in EXCIMAP. This work and collaboration was
prompted by the occurrence of dramatic European floods in the years following 2000.
5 Source: http://ec.europa.eu/environment/water/flood_risk)

Member States are required to undertake a number of specific tasks, including the following
actions, in accordance with various deadlines:
• Preliminary flood risk assessment, by the end of 2011.
• Flood hazard maps and flood risk maps, by the end of 2013.
• Flood risk management plans, by the end of 2015.
UK Compliance
In the UK the first two items have been completed by the target dates, while the third is still
underway. The EU directive stipulates that these activities be revisited on a 6 year cycle of
planning.
Overall responsibility for implementing the EU directive lies with the central government, but
legislation sets out the specific responsibilities of the Environment Agency (EA), who are a
‘non-departmental public body’, under the law. Certain responsibilities are delegated by the
EA to municipal government (referred to as Lead Local Flood Authorities, or LLFAs), whilst the
EA retain overall responsibility for publishing coordinated mapping at the national scale.
Hydrology (Flow Rates)
In the UK a fairly standard and prescriptive method is provided for calculating flow rates for
various frequencies of occurrence. These were initially developed in response to flooding in
the 1960s, but have since been updated. The practitioner is provided with guidelines and
computer programs that lead them through the calculations. There is relatively little latitude
for interpretation or variance from one practitioner to the next. In part, the UK lends itself to
this approach given its relative small geographic area and the availability of measured flow
data for rivers across the country.
Flood Risk Assessment and Mapping
As part of the updates to flood hazard and risk mapping required to comply with the Flood Risk
Regulations, the Environment Agency produced a set of guidelines to ensure consistency and
suitability of data. A key requirement is that floodlines should be delineated for three flooding
events: 1:30 year, 1:100 year and 1:1,000 year.
The revised flood hazard maps published at the end of 2013 (in accordance with the EU Flood
Directive) are available online via the EA website in an interactive map viewer. As per EU
directive requirements:
• Flood hazard areas are delineated as high, medium, low (which relate to return periods
of 30, 100, and 1000 years respectively).
• Flood risk maps are provided for areas where 30,000 people or more could be affected.
Flood risk maps build on the flood hazard mapping but include geo-referenced

information such as hospital and key transportation infrastructure. These risk maps are
published in PDF format on the EA website.
Planning Policy Statement 25 sets out requirements that must be satisfied in order for
development to proceed in certain flood zones. These requirements are intended to prohibit
construction in flood vulnerable areas; although certain types of development can proceed in
lower risk areas subject to passing the required tests (the sequential and exception tests). The
intention is to keep all new development out of medium and high risk areas (Zones 2 and 3),
and to manage new 'water-compatible' development in lower risk areas (Zone 1).
Database and Access to Mapping
The EA have made available various environmental data in GIS format for download from their
website. This includes historic flood data, and flood alert areas. It doesn’t appear to include
current flood hazard/risk mapping though.
Germany, Switzerland and France
Hazard Mapping
Germany
Germany has floodplain maps for most rivers. The maps include flood extent, flood depth,
flood danger and quantitative risk (damage). Other characteristics may include multiple
numbers of classes of flood extent, flood danger, flood risk and return periods. The maps are
used for spatial planning, construction and public awareness. Maps are typically produced for
watercourses with a drainage area exceeding 10 km2.
Mapping is conducted by the various states of the country although in recent years it was
recommended that it be managed by the federal government.
Several different return periods are considered; 1:10, 1:30, 1:50, 1:100, 1:300 years and
extreme events. As a minimum the 1:100 year flood must be considered, although on larger
rivers such as the Rhine the standard may increase to as much as 1:500 years.
Switzerland
Switzerland has floodplain maps for almost the entire country. The information is typically
included for a single return period; however in some cases multiple events may be included.
The maps include flood extent, flood depth, flood danger and qualitative risk. The maps are
used for emergency planning, spatial planning, and construction.
For flood hazard maps developed at a scale of 1:25,000 the extent of the flooding typically
represent an extreme event (generally set equal to a return period of 1:1,000 year). Flood
hazard maps that are developed at a scale of 1:5,000 include floodlines for return periods of
1:30 years, 1:100 years, 1:300 years and the extreme flood event.

France
France has floodplain maps for essentially the entire country. The maps are available on-line
through a simple to use and interactive website. The maps include flood extent and historical
flooding where available, as well as exposure/coping capacity data and qualitative risk. The
maps typically include floodlines for a single return period (1:100 year) but may include
multiple events. The maps are used for spatial planning (binding), construction and public
awareness.
The PPRI maps (Plans de Prévention du Risque Inondation), typically show the extent of one
reference flood; either a historical flood or the 1:100 year flood. “Flood Directive Maps” used
for 120 Areas of Potential Significant Flood Risk include three probabilistic hazard lines
including the 1:100 year flood, as well as one more frequent and one less frequent.
Governance
Germany: Responsibility of mapping has been passed down to regional governments. Each of
the sixteen states (Landen) of Germany produced their own maps but recommendations have
been made to have this done at a national level as per the 2010 LAWA German Working Group
on Water Issues of the Federal States and the Federal Government.
Switzerland: Responsibility of mapping has been passed down to regional governments. Maps
prepared by each of the 26 Cantons indicates areas at risk of various hazards including floods,
avalanches, landslides and rock fall
France: Responsibility of mapping has been passed down to regional governments.
Regulations
Germany: There is binding legislation that restricts or prohibits developments in flood-prone
areas.
Switzerland: Regional governments can decide for themselves how strictly flood zones are
incorporated into their spatial planning policies. However, recommendations made by the
central government regarding flood zones are generally adhered to.
France: There is binding legislation that restricts or prohibits developments in flood-prone
areas. The Code de l'environnement, Chapitre VI - Evaluation et gestion des risques
d'inondation created by Law No 2010-788 on July 12, 2010, Article 221 describes who and how
flood risk areas should be documented and dealt with. (http://www.legifrance.gouv.fr/).
Flood Risk Database
All three countries have a flood risk data base sufficient to produce qualitative risk maps. In
the case of Switzerland and France risk is divided into three to five risk zones. Population,
urban settlement and infrastructure are used as indicators for exposure.

Access
In Germany some maps are currently available on line as PDF files. The objective is to have all
maps available by the end of 2015.
France has on-line interactive flood maps and risk maps for the entire country and its various
regions. An advantage of the system is that it uses a common layout for all departments in
France despite the fact that different sources of information may be at the basis.
Some Switzerland flood maps can be found on line, however, a common site for all cantons
does not appear to be available.
Australia
The Australian Government guides and supports the State and Territory Governments by
providing frameworks within which the states and territories establish legislation, policies, and
standards for flood risk management. Local Governments have significant roles and
responsibilities for disaster mitigation and management at the local level through
arrangements that vary according to state and territory laws, practices and agreements.
The Australia Government is carrying out an ongoing extensive update of its policy documents,
including manuals and best practice guidelines. The focus is on five primary areas to improve
their effectiveness with respect to flood risk management (FRM) and emergency response.
These include:
1. Adopting a whole-of-nation resilience-based approach to disaster management.
2. Developing a nation-wide flood risk information portal to improve the quality, availability
and accessibility of flood information in Australia.
3. Updating of the Australian Emergency Manuals on flood management published by
Emergency Management Australia (EMA).
4. Revising of Australian Rainfall and Runoff (ARR) by Engineers Australia to improve the
estimate of peak flow rates.
5. Generating nationally consistent flood mapping.
It is anticipated that the various FRM initiatives and updates will: allow consumers to be aware
of the natural disaster risks that they face and provide a consistent approach to the collection
and provision of flood risk information; allow stakeholders to access key information to help
them to understand their level of risk and to understand who to approach to obtain detailed
analysis; and allow insurers to have access to the information they need to price flood risk at a
property level and be more willing to provide flood insurance, since they would have the data
that they need.

Extent of Existing Standards
Currently, there are no nationally accepted or consistent standards for models and
approaches, or for the analysis and reporting of flood risks in Australia. It is usually a matter
for each individual State/Territory or local government authority to decide on how the
mapping is to be done and what form the output of the mapping activity might take, including
the level of detail and public availability. It is also recognized that a sophisticated or consistent
understanding of flood behaviour across all areas of Australia is neither practical nor
necessary. The degree of effort required and approaches used will vary depending upon the
complexity of the flood situation, and the information needs of government and the
community to understand and manage risk (McLuckie, 2013).
Hydrology (Flow Rate)
Procedures for calculating flood flows for different return period are documented in the
Australian Rainfall and Runoff (ARR, 1987), which is the national guideline for estimating
design flood characteristics in Australia. The current edition was published in 1987 and an
update is presently underway (Engineers Australia, 2013b). The ARR and other guideline and
best practice manuals identify the following methods as being normally used for flood
discharge estimation: frequency analysis, indexed flood method, or hydrologic modeling.
The SCARM Report6 notes that peak flow rates should be calculated for a full range of return
periods up to and including the Probable Maximum Flood (PMF)7. The return periods that are
used for floodplain mapping and planning purposes (referred to as the Defined Flood Event –
DFE) may vary depending on State and Territory, although the 1:100 year event is most
typically adopted.
Flood Risk Assessment and Mapping
According to the SCARM Report, flood maps should ideally show the extent, depth, velocity
and hazard of flooding for the DFE, but should also show the extent of the PMF, which is used
to identify the floodplain and flood-prone lands. Some jurisdictions also require that the
location and floor levels of flood prone buildings be identified on the mapping (QRA, 2011b).
The extent to which the above criteria are actually depicted varies among States/Territories
and local governments. Queensland (QRA, 2011b), for example, requires the inclusion of flood
depths and velocities to be shown, as well as flood risk zones.
In some cases essential infrastructure services such as water supply and electric power are
included on the mapping. In Queensland, Councils are also required to give consideration to
determining appropriate floor levels for habitable rooms, which must be in accordance with
Section 13 of the Building Regulation 2006.
6 SCARM Report: Standing Committee on Agriculture and Resource Management, Report 73, 2000.
7 PMF is determined on the basis of the probable maximum precipitation (PMP), which is the maximum rainfall that could
physically occur at a location of interest.

In addition to the DFE (typically 1:100 year event), mapping may also include the 1:200 year or
1:500 year floodlines, particularly if an essential service is at risk of flooding. In addition to the
DFE water level, a freeboard of 0.3 m to 0.5 m is often designated to be used for government
guidelines and policy instruments to define the standard for new residential development to
limit growth in risk. The freeboard is generally viewed as a “factor of safety” in recognition of
uncertainty in estimating flood risk, and is not intended to increase the flood protection level
or target floods larger than the DFE.
The SCARM Report recognizes the importance of updating flood risk information on a regular
basis. Flood risk and floodplain mapping should be reviewed and updated as required at
regular intervals of not more than 5 to 10 years. Such updates may be triggered by various
major developments such as constructing a new dam, or where there have been rapid land-use
changes in a relatively short time frame.
Database and Access to Flood Maps
The National Flood Risk Information Portal, to be hosted by Geoscience Australia, was
announced in November 2011. The Portal, which is currently in a BETA phase, provides a single
access point to existing flood mapping data for users throughout Australia. In addition, a new
national standard has been developed to provide a framework to guide organizations in
providing nationally consistent datasets to be used for the Portal (NFRIP, 2012).
It is expected that once the nation-wide flood risk information portal is fully commissioned,
access to flood information and mapping will be significantly enhanced, and so will community
awareness of flood risks, which will in turn improve and better inform decision making in a
wide range of areas including emergency management, land use planning and provision of
insurance.
New Zealand
The two main pieces of legislation in New Zealand relevant to climate change and flood risk
management are the Resource Management Act 1991 (RMA) and the Civil Defence Emergency
Management Act (CDEM) 2002.
The RMA requires regional authorities to control the use of land for the avoidance or mitigation
of natural hazards. Territorial authorities are required to control the actual or potential effects
of the use, development or protection of land, including for the purpose of avoiding or
remedying natural hazards. The Resource Management (Energy and Climate Change)
Amendment Act 2004 further requires local authorities to have particular regard to the effects
of climate change.

The CDEM Act is another key piece of legislation for flood risk management. The Act primarily
focuses on the sustainable management of hazards, resilient communities and on ensuring the
safety of people, property and infrastructure in an emergency. The CDEM Act recommends an
approach based on risk reduction, readiness, response and recovery.
Standards and Guidelines
New Zealand does not have existing national technical standards for the preparation of
floodplain maps or assessing natural hazards. There is no National Policy Statement (NPS) for
river flooding under the RMA. A draft NPS was completed around 2007 and a board of inquiry
was established, but, the NPS process stalled around matters of cost-benefit and the NPS has
not been made released for public comment.
The Flood Hazard Risk Standard (NZS 9401:2008) was developed by committee and released in
2008. The purpose of the standard is “to provide an agreed best practice approach for local
and central government, professionals (planners, engineers, hydrologists, scientists, risk
managers, lawyers and so on), developers, utility suppliers, property owners and communities
to ensure that proper consideration is given to all aspects of flood risk when making decisions,
so that over the long term, the risk of flood damage decreases”. The standard is a voluntary
tool that provides a set of principles to help decision making and promote good practice in
flood risk management and is not technical, prescriptive or performance based.
The Flood Risk Management Governance Group comprising representatives of local and
central government and the Institute of Professional Engineers developed a draft New Zealand
Protocol on Managing Flood Risk in 2005. Under this umbrella it was intended to develop
implementation guides and modules for a number of flood topics such as catchment
management and risk communication but funding was not obtained to continue this work.
The National Institute of Water and Atmosphere (NIWA) is currently developing tools that will
aid practitioners and managers to better assess flood risk. The system is referred to as the
High Intensity Rainfall Design System (HIRDS). The High Intensity Rainfall Design System is a
web-based program that can estimate rainfall frequency at any point in New Zealand. It can be
used to estimate rainfall depths for hydrological design purposes, and to assess the rarity of
observed storm events.
In urban areas, the standard is usually protection for floods up to the 1:50 year return period,
however, in many cases a higher level of protection is provided.

United States of America
Of the nations reviewed, the USA has the most extensive nationwide program in terms of
identifying, publishing and updating flood hazard information. The Federal Emergency
Management Agency (FEMA), as the lead agency, publishes a series of documents that
encompass both standards and guidelines for all aspects of floodplain mapping, from
hydrology and hydraulics through to the development of base mapping and data bases.
The focus in the USA is the identification of flood risk in the context of flood insurance and less
on controlling development in the floodplain. Even the terminology used, such as, Flood
Insurance Rate Maps (FIRMs) and Flood Insurance Study (FIS) reports relates to an insurance
focus. Although, the products produced (i.e. maps, reports and databases), are essentially the
same as other countries and jurisdictions.
Standards and Guidelines
FEMA has produced extensive guidelines and specifications covering all aspects of the
implementation of the NFIP and production of flood risk maps. In total, 10 guidelines
documents are available. They address methods for completing calculations, reporting
requirements, and flood risk database requirements.
The base flood that is used for assessment and mapping is the 1% annual chance flood (i.e.
1:100 year flood) but any of the following lines may also be shown on the maps:
• 0.2% (1:500-year) Annual Chance Flood Hazard area.
• Area with reduced flood risk due to Levees.
• Floodway.
• Flood Insurance Zones.
• Future Conditions 1% Annual Chance Flood Hazard area.
Regulations
The Regulatory Floodway is defined as the channel of the river or other watercourse and the
adjacent land area that is reserved from encroachment in order to discharge the Base Flood
(1:100 year) without cumulatively increasing the water surface elevation by more than 0.3 m.
This criterion is used unless the State has established more stringent regulations for the
maximum rise in water surface elevations, through legally enforceable statutes.
Within the Regulatory Floodway communities must prohibit encroachments, including fill, new
construction, substantial improvements and other development unless it has been
demonstrated through hydrologic and hydraulic analysis that the proposed encroachment
would not result in any increase in flood levels within the community during the base flood
discharge (1:100 year).

Communities must require that all new construction and substantial improvements of
residential structures within the floodplain have the lowest floor (including basements)
elevated to or above the base flood (1:100 year) level.
Mapping
FEMA has detailed documents for topographic base mapping (Appendix A: Guidance for Aerial
Mapping and Surveying and Appendix L: Guidance for Preparing Digital Data and Flood
Insurance Rate Map Databases) for use in the preparation of floodplain mapping products that
are updated as required. Therefore, the guidelines include and consider new technologies such
as LIDAR. The basic contour interval specified for the base mapping is a 0.6 m (2 ft.) equivalent
contour interval for flat terrain and a 1.2 m (4 ft.) contour interval for rolling to hilly terrain.
The floodplain maps (FIRM) include standard base information such as buildings and the road
network and, depending on the levels of study, various floodplain information as detailed
above. FEMA has also developed a database to store digital GIS data used in the map
production process, as well as, tabular information found in the FIS report.
Public Accessibility
FEMA has developed a Map Service Centre portal where the public can access maps, Flood
Insurance reports and other information. It contains information specifically targeted to
homeowners, real estate agents and insurance agents and also has a ‘Live Chat” service. FEMA
is also adding GIS information layers.
3.2 Summary of Key Practices
Following from the international review, a number of key practices and standards were
identified that will help to inform the development of the National Floodplain Management
Framework for Canada. Each of these, including how they tie to the Guiding Principles, is
summarized below.
Technical Accuracy
1. Comprehensive Guidelines are a key requirement in ensuring that mapping is as accurate as
possible. As an example, the USA through the Federal Emergency Measures Agency (FEMA)
has the most extensive set of standards and guidelines used to prepare and update
floodplain mapping. They address all aspects of floodplain mapping, from data collection and
required analyses through to the preparation of flood hazard mapping.
2. Methods for Calculating of Flow Rates used for Floodplain Mapping can be highly variable
and inconsistent. Often this translates directly into significant over or under estimation of
flood risk. To address this concern there is merit in developing a consistent and prescriptive
approach across similar geographic regions. The UK and the USA in particular are fairly
prescriptive in providing guidelines and parameters for estimating flow rates, whereas
others may rely on the development of hydrologic models for individual watersheds.

3. Vertical Basemap Accuracy - There is a trend to more accurate base mapping through the
use of LiDAR. Where mapping is more recently developed on a regional basis (UK and
Alberta) vertical accuracy is in the range of 0.15 metres.
4. Integration of Mapping and Flood Risk Data is fundamental to managing flood risk. All
countries are generally moving from static hazard mapping through to more dynamic
mapping that is integrated with a flood risk database. However, in all cases this is a work in
progress.
5. Mapping of More severe Events allows for a better understanding of risk. Most commonly
Hazard Mapping include the worst of the 1:100-year event and the historical flood of record,
However, current standards in several countries recommend that more severe events also
be mapped. These range from 1:300 years to 1:1,000 years in Europe to as much as the
Probable Maximum Flood in Australia. These more severe events are more often used to
understand risk and are not necessarily used for flood hazard mapping or for regulatory
purposes.
6. Management of New Development in Floodplains is inherent to flood plain management in
all jurisdictions. Standards and methods vary considerably between jurisdictions. However a
minimum standard seems to be that any new development should be protected from
flooding for a minimum of the 1:100 year flood, and that any new development should not
increase upstream flood risk.
7. A National Mandate can be effective in providing consistency in both vision and in priority.
In the countries reviewed the development of standards is generally the responsibility of the
national or federal government although implementation occurs at a lower tier.
8. Flood Risk Assessment can be used to establish priorities and perhaps in providing variable
standards. Some countries such as the UK consider risk as a factor in establishing the
standard for flood protection.
9. On-line Access is the most effective manner to ensure that flood risk information is readily
available. On-line access to Flood Hazard mapping is either available or will be available in
most countries. In addition, coordination and distribution of this information is more
typically a national/federal responsibility.

Current
10. Climate Change can have a significant impact on flood risk. There is a recognition across
most nations reviewed that Climate Change affects risk, but there does not appear to be a
consensus how this should be incorporated into mapping and risk assessment.
11. Sea Level Rise is of particular concern in coastal areas that are either low-lying or have
dynamic shorelines that are prone to erosion. Although further work is required, there is a
clear understanding of the need to consider and account for sea level rises coupled with
storm surges in assessing and managing coastal flood risk.
3.3 Canadian Review
Flood plain mapping in Canada, as it is understood today, began in the 1960s. However, prior
to 1975 mapping across Canada was relatively limited and inconsistent in terms of approaches
and standards. In 1975 the federal government established the Flood Damage Reduction
Program (FDRP) to map existing flood hazard and to discourage development in flood prone
areas. FDRP was implemented over approximately a 20 year period as a joint federal-provincial
initiative for all provinces and territories except Prince Edward Island and the Yukon Territory.
Through the program, flood hazard mapping was prepared for more than 900 communities
across Canada. In Ontario alone the mapping extended along 15,000 km of watercourses and
lake shorelines. Following termination of the program, floodplain mapping in each province
has been solely the responsibility of the provincial or territorial governments.
The first part of this section of the report summarizes flood plain mapping practices, key
standards, and unique challenges for each province and territory in Canada. Additional detail is
provided in Review of International and National Flood Mapping Practices, May 2014 . The
second part presents a compilation of comments and recommendations from a wide range of
subject matter experts. All of the information in this section of the report will help to inform
the National Floodplain Management Framework.
British Columbia
Summary of Current Practices
Province wide flooding in 1974 prompted British Columbia to start a Floodplain Mapping
Program and floodplain maps were produced which provided mapping for many of the major
populated areas along major rivers. Local governments used these maps to develop floodplain
bylaws and the Province and some local governments used them to adjudicate applications for
subdivisions. Later the Province stopped producing new floodplain maps and discontinued
updating and maintaining the maps. Then in 2004, the Provincial Government passed the Flood
Hazard Amendment Act which transferred more authority to local governments to manage land
use in floodplain areas and local governments became responsible for creating new floodplain
maps and for updating existing ones.

During this transition, the Province undertook an extensive mapping initiative to provide
floodplain and flood hazard assessment information (maps and reports) that had been done to
date and made it accessible to local governments. Interactive maps that identify water bodies,
high hazard areas, suspected high hazard areas, flood protection works and floodplain extents
were made available to local governments. Polygons of hazard areas and floodplain extents
were provided to municipal governments for inclusion in land development bylaws. The
database is current to 2003.
Today a few municipalities have updated some of the floodplain maps and some have initiated
their own studies of new areas previously unmapped (Personal Communication 2014).
However, most of the floodplain maps produced under the Floodplain Mapping Program and
the Flood Hazard Maps produced in 2004 have not been updated/maintained and are now
considered historic information. The Province remains engaged, in a limited way, with some
strategic provincial level projects such as developing guidelines for assessing flood hazards.
Key Map Standards and Regulations
Two-zone mapping is not used in BC; the current Floodplain Mapping Guidelines and
Specifications for BC (FBC 2004) instead references the “Design Flood Level” and the “Flood
Construction Level”. British Columbia uses the 1:200 year event or the flood of record as the
design flood for floodplain mapping. The “Design Flood Level” is the water surface level
associated with the design return period event applicable for a given river. A “Flood
Construction Level” is then determined by adding an allowance for freeboard on top of the
Design Flood Level, which defines the minimum elevation of the crest of a standard dyke or
defines the elevation where construction can commence. The Flood Construction Level is the
higher of a freeboard of 0.3 m added to the design peak instantaneous flow or a freeboard of
0.6 m added to the design peak daily flow. (FBC 2004)
Unique Challenges
Challenges that remain unique to floodplain management in British Columbia relate to coastal
flooding, flooding due to debris flows on alluvial fans in the mountainous areas, and possible
failure of managed and “orphan” dikes, putting protected communities at increased risk.
In some areas of British Columbia (mainly the SE Kootenay Region) the Flood Hazard Maps
have gone beyond typical floodplain mapping by also identifying and mapping areas subject to
high erosion hazard (shifting channels and debris flows and alluvial fan hazards. The polygons
of these mapped high hazard areas have been adopted into some municipal development
bylaws, similar to floodplain extents. Flows through alluvial fans are extremely unstable. Large
flows from high mountain elevations can accumulate an enormous volume of sediment, forest
material, and gravel. They travel down well-defined and stable mountainous channels. At the
base of these hardened, relatively narrow, channels, the flow enters a broad flood area, losing
speed and depositing debris in a “cone-shaped” alluvial fan.

This hazard of alluvial fans and debris flows is unique to mountainous areas of Canada,
especially British Columbia. British Columbia has provided mapping resources to municipalities
to identify the locations of these hazards. Polygons of these hazard areas have, in some cases,
been adopted into local government bylaws so that development is actually prevented.
Another unique challenge that the Province has addressed related to floodplain mapping is the
risk of coastal flooding. In 2011, BC produced Coastal Floodplain Mapping – Guidelines and
Specifications (KWL 2011) as a standalone document apart from the 2004 Floodplain Mapping
Guidelines (FBC 2004). Not only does it take into account design storm impacts for defining the
Flood Construction Level, but it also specifies choosing a design year so that an appropriate
allowance for future sea level rise can be estimated. The Flood Construction Level for coastal
mapping takes into account the “higher high water large tide”, the sea level rise, a factor for
storm surge, a factor for wave effect, and a nominal freeboard of 0.6 m. Tsunami design
elevations (produced by EMBC) are also included on coastal floodplain mapping along with the
Flood Construction Level. The Guidelines (KWL 2011) reference numerous other studies and
guideline reports that address coastal flooding design challenges.
Finally, British Columbia faces the challenge of over 1,100 km of dikes that provide flood
protection. Dikes are used both in inland communities and coastal communities to protect
against floods. Numerous dike breaches have been documented from past flooding, and the
possibility for future breaches is an ongoing risk especially where “orphan” dikes exist (about
100 in the province). Orphan dikes are dikes that are not maintained by a diking authority.
Many of these orphan dikes were constructed under emergency conditions and generally lack
adequate planning and engineering design. The FBC Guidelines address the need for modelling
dike breaches when assessing floodplain maps and provide specifications for how to do so.
The risk to the Lower Fraser River Floodplain (one of Canada’s most intensely developed
floodplains) is affected by dike protection, highlighting this critical focus on understanding,
modeling, and managing dike breaches.
Alberta
After the FDRP ended, Alberta initiated the provincial Flood Hazard Identification Program
(FHIP), which built on the FDRP foundation and continues to assist municipalities in identifying
flood-prone areas.
The River Hazard Management Team of Alberta Environment and Sustainable Resource
Development currently manages provincial floodplain and hazard mapping. Alberta has a
recognized strength in geomatics and has invested in making their mapping and products
publically available through an online data portal.
Updates to historic floodplain mapping studies are ongoing. Calgary’s original floodplain
mapping study completed in 1983 has undergone multiple updates, the most recent being in

2012. With the recent flooding events of 2013, floodplain management continues to be a
provincial priority. A recent update of the Municipal Government Act, specifically Bill 27, has
changed the way that development and floodproofing in the floodway may be approved in the
future, and may impact how the floodway and the flood fringe areas are defined or managed.
This policy shift has brought necessary questions to the forefront of provincial discussion,
including what to do with the existing floodline if different standards are applied.
Alberta uses a two-zone mapping standard for floodplain mapping in the province, which was
encouraged through the FDRP and continues to be applied through the FHIP Guidelines
(Alberta Environment 2011). The entire floodplain is known as the “Flood Hazard Area”. The
“floodway” is defined as the channel where the entire design flood flow can be conveyed with
a maximum 0.3 m water level rise due to river encroachment or where there is a depth of at
least 1 m, or where there is a flow velocity of at least 1 m/s. The “flood fringe” is the
remainder of the flood hazard area that falls outside the floodway, with water depths less than
1 m and water velocities less than 1 m/s. These zones define where development can occur;
new development is largely prohibited in the floodway and any development in the flood
fringe must be floodproofed to the appropriate flood protection level.
For defining the flood hazard area, Alberta uses the maximum of the 1:100 year return period
floodlines or the flood of record. As ice jams can significantly impact water levels, the 1:100
year water levels must be based on the greater of ice-impacted water levels or open-water
levels.
Unique Challenges
Distinct challenges for floodplain management in Alberta include unique weather patterns,
mobile beds, sedimentation, and debris flows. The weather patterns are impacted by the
mountain ranges along the western border of the Province. Storms heading north from the
warm south hit the mountains at high elevations and cause large amounts of precipitation
combined with melt events in the headwaters of the mountain streams that lead to extreme
flow events as the rivers flow out onto the prairies. Due to the distance between the storms
causing flood events and the greatest flood impacts, a typical approach in some other
provinces of applying a “regional storm” over a watershed to predict resultant flows is not
applicable in Alberta. Therefore, flood frequency analysis based on these large events is the
basis of determining flood levels for individual rivers instead of using design storm inputs to a
hydrologic model.
A related, yet separate, challenge has to do with mobile beds, debris flows, and sedimentation.
Along with those extreme flows, high sediment load including debris, can be transported into
the flatter plains or more undulating foothills, where sedimentation occurs as flow velocities
decrease. Although Alberta does not explicitly map hazard areas that are associated with these
debris flows, they are a recognized risk to impacted communities.

Another hazard that has widespread impacts is high water levels due to ice jams and ice flows.
There are two primary phenomena that can cause high water levels due to ice impacts: one is
due to break-up ice and the second is due to frazil ice. Break-up ice is frequently washed
downstream prior to high spring flows occurring. However, if high flows coincide with the
timing of ice break-up, water levels can be significantly increased (relative to open-water
levels). Frazil ice (i.e., ice crystals that form in flowing streams when the water surface is
supercooled) can often form in streams and rivers. It can form blockages below the water
surface and can develop concurrently with high spring flows, significantly increasing upstream
water levels and causing flooding. Historic high water levels due to ice flows can be higher
than flood levels caused by open-water flows. In either case, the higher 1:100 year return
period levels (cause either by ice or open water) is chosen as the design water level for
floodplain delineation in Alberta.
Alberta has also recognized the need for a different approach to flood hazard mapping of its
alluvial fans (similar to British Columbia) as a result of the 2013 events in the Bow Corridor,
and is now looking at developing a framework for hazard mapping in these areas.
Saskatchewan
Updates to floodplain mapping are ongoing, including a recent update to the hydraulic
modelling of Regina. There is no current provincial strategy for updating the mapping,
although there are frequent emergency flood damage reduction programs put in place to
respond to annual flood risks.
Digitization of the original floodplain maps is being completed by the Water Security Agency; a
combination of the updated digital maps and the original floodplain maps are accessible to the
public via GeoSask (GeoSask 2013), an online portal where the static maps can be
downloaded.
Key Map Standards
Saskatchewan has gone well beyond the minimum standards set by the FDRP in mapping the
floodplain; they use a 1:500 year return period flood, with an additional 0.5 m freeboard, for
defining the estimated safe building elevation. Saskatchewan does not have provincial
guidelines for floodplain mapping, but continue to use the guidelines from the FDRP. The
floodway is determined as the channel having equal or greater than 1 m depth or equal or
greater than 1 m/s velocity, with the remaining floodplain zoned as the flood fringe.

Manitoba
Since the end of the FDRP, no further communities have been mapped. Currently,
development in the floodplain rests with local governments and municipalities. Two
exceptions to this management structure are within two provincial “Designated Flood Areas”:
The “Red River Valley Designated Flood Area” and the “Lower Red River Designated Flood
Area”. The Provincial Government is tasked with setting flood elevations and approving
development within these areas.
Manitoba does not have an online floodplain mapping website where the public can access
floodplain maps, but maps may be available through municipal government offices.
Key Map Standards
Manitoba continues to use the Flood Damage Reduction Program guidelines for floodplain
mapping. The Province uses the 1:100 year design flood, or the flood of record, to define the
total floodplain, except in the City of Winnipeg, where the 1:160 year design flood is used.
Manitoba uses a two-zone mapping approach to differentiate between the floodway and flood
fringe. The floodway is defined where the depth of flooding is greater than 1 m. In the City of
Winnipeg, the floodway also takes into consideration the point at which the water level rises
0.1 ft. (i.e., 0.03 m) due to constraining the effective flow area. The flood fringe is the
remainder of the floodplain beyond the floodway.
Unique Challenges
Manitoba has had extensive flooding along most rivers in the province. Flood protection
infrastructure, such as the Winnipeg Floodway, has been developed to deal with major runoff
events. The significant flood events of 1997 and 2010-2011 also saw flood mitigation works
implemented through the Canada-Manitoba Floodproofing Programs to help develop flood
protection for homes, farms, businesses and communities to help alleviate risk of future
damages.
Ontario
From an administrative perspective Ontario is unique among the provinces in that floodplain
mapping is administered through the 36 Conservations Authorities, or the Ministry of Natural
Resources in areas that are not served by one of the Conservation Authorities. Overall in
excess of 90 percent of floodplain mapping is administered by the Conservation Authorities.
The status of mapping and the extent of any updates are highly variable across Ontario. In
urban growth areas mapping is continually being updated, however in areas that are less
populated or are not undergoing rapid growth the mapping tends to remain unchanged from
what was prepared under FDRP.

Since the majority of the maps are held at individual Conservation Authorities the accessibility
of the maps and floodplain information is also variable. While all Conservation Authorities use
and are willing to share the information, it may require a visit to the Conservation Authority
office to view the maps. Most Conservation Authorities have at least digitized the paper maps,
some have digitized the floodline with the ability to place the line as a layer on other bases and
some Conservation Authorities have fully integrated Digital Elevation Models (DEM). Maps for
many Conservation Authorities are accessible on their web sites or paper copies can be
obtained upon request (sometimes for a fee). The MNR has digitized all their floodplain maps
and they are available through Land Information Ontario (LIO).
In Ontario the Regulatory event used for flood hazard mapping varies by geographic location.
As defined in the MNR’s Technical Guide8, the flooding hazard limit is the greater of:
1) The flood resulting from a rainfall actually experienced during a major storm such as the
Hurricane Hazel storm (1954) or Timmins storm (1961), transposed over a specific
watershed and combined with the local conditions, where evidence suggests that the storm
event could have potentially occurred over the watersheds in the general area;
2) The one hundred year flood; or
3) A flood which is greater than 1) or 2) which was actually experienced on a particular
watershed or portion thereof, for example as a result of ice jams and which has been
approved as a standard for that specific areas by the Minister of Natural Resources; and
The exception is where the use of the 1:100 year flood or actually experienced event as the
flood standard for a specific watershed, even, though it does not exceed the Hazel or
Timmins event, has been approved by the Minister of Natural Resources, (where past
history of flooding supports the lowering of the standard)
In practice this means that there is considerable variance in the event that is used for defining
flood hazards. For example, in central Ontario, including Toronto, Hurricane Hazel is used for
mapping purposes. Although it does not have a defined return period, runoff is typically 3 to 5
times greater than the peak generated by a 1:100 year storm. In contrast eastern Ontario,
including Ottawa, uses the 1:100 year event to define flood hazard limits.
Within Ontario there are three approaches to floodplain management; one zone concept, two-zone
concept and Special Policy Areas.
• Under the one-zone concept the Regulatory floodplain is treated as a single unit and all
development is prohibited or restricted within the floodplain. Development in all flood plains
in Ontario is subject to the one zone concept unless otherwise approved.
8 Source: Technical Guide – River and Stream Systems Flooding Hazard Limit, 2002

• Under the two-zone concept the Regulatory flood plain is divided into the floodway where
development is prohibited and the flood fringe where development may be permitted
subject to certain conditions. Two-zone floodplains are common in existing urban areas, but
are rarely approved for new development.
• Special Policy Areas (SPA) are applied within a community that has historically existed in the
floodplain where the one zone and two zone flood plain management approaches have been
demonstrated to be too stringent and would likely cause significant social and economic
hardships to the community. The area specific policies of the SPA are intended to provide for
continued viability of existing land uses while being sufficiently protective against natural
hazards. It is not intended to allow for new or intensified development and site alteration, if
a community has feasible opportunities outside of the flood plain.
Ontario also has been active in developing coastal (lakeshore) natural hazard mapping, defined
as the 1:100 year lake level plus the worst case of: wave uprush, 1:100 year toe erosion plus
stable top of slope, or wave uprush plus dynamic beach allowance. The Regulation Limit, where
permits are required for development is defined by adding an additional 15 metres to the
above.
Unique Challenges
Although floodplain maps have been produced for in excess of 15,000 km of watercourse and
shorelines within Ontario, one challenge is that there are also still areas of the province that
are not mapped, where the mapping is dated, or where the mapping is an estimate only.
Another challenge is lack of consistent guidelines and implementation standards for the
analysis and delineation and mapping of flood hazards since the termination of the FDRP. In
part this is because the development of floodplain mapping is the responsibility of individual
Conservation Authorities with widely varying resources available to maintain and/or update
mapping.
Québec
Currently, most of the hydrologic / hydraulic analyses and floodplain mapping has been/is
being done in-house by the Centre d’expertise hydrique du Québec (CEHQ). Some 5,800 km
of watercourses or shorelines have been mapped between 1979 and 2010.
Statistical hydrologic analyses are preferred over hydrologic modelling with design storms in
determining design peak flows. Steady state hydraulic modelling is, for the most part, used to
determine flood water levels. All maps are available in GIS formats.
Impacts of climate change are considered in urban areas where design storms are used to
generate flows. This is addressed by increasing rainfall intensity by 10 to 20 percent depending
on the design storm.

There are currently no officially published standards, in the province of Quebec, for the study
and preparation of floodplain maps. However, based on a preliminary set of guidelines
prepared in 1998 by the Ministère de la Sécurité Publique and the Ministère de
l’Environnement et de la Faune, and further referred to in a 2007 working document by the
Centre d'expertise Hydrique, two flood levels are determined under free flowing conditons;
one for the 1:20 year flood and one for the 1:100 year flood.
With respect to regulated flood zones in Québec, two flood zones are considered; i) high risk
areas for return period flows of zero to 20 years where no development or construction of
new works are permitted (with a few exceptions), and ii) moderate risk areas for return period
flows of 20 to 100 years where filling and the construction of buildings is prohibited without
flood proofing for the 1:100 year event.
Unique Challenges
Québec has over 1,000,000 lakes and 130,000 streams of which 4,500 are rivers. In all, 2
percent of the world's fresh water is in Québec. Only a small portion of these bodies of water
have flood maps. The lack of available funding and the absence of a provincially regulated
framework to produce flood maps is limiting the extent of this work.
New Brunswick
While the Province of New Brunswick continues to map the extent of major inland flood events
as they occur, it is not currently performing any systematic, on-going activity to update
predictive floodplain mapping. Government-sponsored research (flood frequency analysis, etc.)
has been initiated to support the future renewal of provincial floodplain maps, however, much
of the recent flood mapping effort has focused on coastal flood hazard mapping, accomplished
in partnership with municipalities and the federal government under the Atlantic Regional
Adaptation Collaborative. It should be noted that little inland mapping has been done since the
mid-1990s because it was largely performed under the FDRP. Digital floodplain maps are
available to the public on the GeoNB website, though they cannot be ordered or downloaded. A
provincial flood risk reduction strategy is currently being finalized for release. Among other
things, it is expected to identify a path forward for future floodplain mapping in the province.
Key Map Standards
The events mapped have generally been the 1:100-year and 1:20-year floods (1% and 5% risk
respectively). Mapping is primarily a provincial responsibility, but some municipalities have
completed mapping in partnership with other stakeholders. There are, however, no province
wide standards or regulations with regards to one-zone or two-zone approaches or managing
development in floodplains.

Nova Scotia
Floodplain mapping was produced for five river systems in Nova Scotia under the Flood
Damage Reduction Program in the 1980s. The Province is presently developing an application
based funding program to provide financial assistance to municipalities to conduct flood
assessments including producing floodplain mapping. For the previous mapping produced, the
area within the 1:20 year floodline defined the floodway and the remaining area up to the
1:100 year floodline defined as the flood fringe.
Prince Edward Island
The Province of Prince Edward Island has completed very few riverine floodplain studies. Their
hazard concern is directed toward coastal flooding and coastal erosion. The entire province,
however, is mapped with LiDAR, generally at low tide to get the largest area of coverage.
Limited inland flood mapping was completed in the Hillsborough River watershed in 2010-2012.
Unique Challenges
Prince Edward Island is uniquely placed as the only province which is also an island. As such, the
primary interaction with hydraulic forces is not from rivers, but from coastal factors. The major
issue for Prince Edward Island from coastal interactions, however, is not coastal flooding, which
does occur in localized areas, but rather it is coastal erosion. Every year, the province loses a
significant portion of its land area to the sea. Consequently, flooding is not the dominant hazard
around which provincial action is required. Instead, based on erosion estimates, slope failure
hazard limits are set to keep properties safe. In riverine applications, similar slope hazard limits
are also set and are often significantly higher than the 100-year flood line, essentially offering
dual protection. Prince Edward Island also has a unique jurisdictional issue regarding data
collection for their coastal risk modelling. Coastal data collection is the responsibility of the
federal government, and not of the province. The federal government operates only a single
coastal gauge near the city of Charlottetown. As the area of interest moves further away from
this gauge site, data uncertainly increases and so does modelling error, making the hazard limits
less certain.
Newfoundland and Labrador
In the 1980s and 1990s a number of communities in the province with a known history of
flooding were mapped under the FDRP. In 2008, the province funded a new study for
Stephenville. The Hydrotechnical Study of Stephenville was one of the first in Canada to
delineate climate change based flood risk mapping. In 2010, following the success of the 2008

study, a partnership with Natural Resources Canada funded climate change flood risk mapping
studies for additional areas, including Corner Brook and St. John’s in 2013. The general principle
is to update the maps every 10 years.
The work that is done to determine the flows and flood modelling results are reviewed by a
technical committee. The only models approved for use are part of the USACE suite of
programs (e.g. HEC-RAS, HEC-HMS, etc.). The preferred mapping is to have LiDAR, but there are
no official mapping standards except to have sufficient accuracy to reasonably accomplish the
task of flood mapping. Maps are all added to a GIS database, and they are available to the
public digitally through the government website.
The flows mapped are generally the 1:100 year and 1:20 year floods (1% and 5% risk
respectively), but these flows are also projected to 2020, 2050, and 2080 based on climate
change projections.
Generally, a flood fringe zone is adopted where some development is allowed, but no
development is allowed in the floodway. Flood fringe developments must generally be non-structural,
water related, or minor structures relating to other projects such as pipelines, where
only soil disturbance is involved and not changing the grading of the land.
Yukon
A Flood Damage Reduction Agreement was never negotiated with the Yukon Territory under
the FDRP. Currently, the development of the floodplain and flood risk mapping is seen
primarily as a territorial responsibility with a potential role for municipalities as well.
Flooding is a key vulnerability for Yukon communities given that they are likely to encounter
more frequent flooding into the future as a result of climate change. The need to better
identify floodable areas has been recognized by the Government of Yukon’s Emergency
Measures Organization (EMO). EMO has plans in place for LiDAR surveying to be done in 2014
and 2015 for 13 community areas identified by Yukon staff as the most flood prone areas. The
LiDAR data will be used to produce up-to-date Digital Elevation Models for the flood risk
mapping. Existing elevation data is accurate to the nearest 1 m at best. The LiDAR surveying is
being funded through the federal (AANDC) Climate Change Adaptation Program.
The areas to be surveyed are: Old Crow, Dawson/Klondike Valley, Mayo, Carmacks, Ross River,
Upper Liard, Marsh Lake/Tagish, Carcross (Bennett Lake), Teslin, Whitehorse, Pelly Crossing,
Lake Laberge and Burwash/Destruction Bay.

The creation of a GIS data base is currently in progress. Digital maps are not yet made available
to the public however when the mapping is completed it should be made available to potential
users via on-line pdfs and GIS data. Paper maps would be provided on request.
In addition the Yukon Research Centre, Yukon College has conducted a number of studies on
landscape hazards and climate change adaptation including hydrology-based work in Mayo
and Pelly Crossing areas. These studies used past discharge data to look for trends and
relationships between climate and environmental conditions, such as snowpack, and spring
flooding. In 2014 and 2015 the College will be conducting a similar study in Old Crow that will
also look at the hydrology and flooding.
Key Map Standards
There are documented procedures in place for calculating design flood flows for different
return periods using single station flood frequency analysis (FFA) with regional analysis based
on drainage area. The return periods to be calculated and used for floodplain mapping
purposes have yet to be determined. At this time no standards currently exist for base map
accuracy or for the information that should be included.
Unique Challenges
Challenges facing floodplain management in the Yukon include: sparse data regions, thermal
erosion, coastal erosion and flooding (including at historic sites such as Herschel Island),
flooding due to ice jams (with sudden rise and lowering in water levels that cannot be
forecasted), and the need for hydrologic response scenarios associated with climate change in
the preparation of flood risk mapping.
There are concerns regarding infrastructure such as bridge abutments and community dikes
and their ability to withstand flood waters.
Northwest Territories
FDRP flood risk mapping was completed for nine NWT communities in the Mackenzie River
basin. Scanned copies (PDF) of the flood risk maps as well as shape files derived and/or
adapted from these floodlines are provided to communities by the Lands Administration
Division, Department of Municipal and Community Affairs (MACA), Government of the
Northwest Territories.
MACA staff have re-created the floodway and flood fringe areas from the FDRP maps using
updated (and sometimes expanded) DEM grids of the nine communities and the FRDP flood
elevations. This is a desktop exercise using GIS mapping to demarcate all elevations lower than
the flood level as the floodway and all areas within 1.0 metre as the flood fringe. The
community base mapping used to create these maps is updated every five years.

Unique Challenges
Challenges facing floodplain management in the NWT include: limited capacity for undertaking
the floodplain mapping tasks including few human resources and the lack of in-house expertise
within the territorial government and local institutions; changes in climatic conditions which
are resulting in thermal erosion (coastal areas) and the need to update the mapping more
frequently in these areas; and the current situation where communities can elect to use the
mapping or not use the mapping. Limited capacity not only affects NWT’s ability to
produce/update official flood zone maps but also the territory’s ability to understand and use
these products at the community and territorial levels. This situation is seen as a major factor
in a community’s decision to use or not use these maps.
Nunavut
The Nunavut Territory was established in April 1999. Previously the Nunavut area was part of
the NWT. None of the FDRP mapping done for the previous NWT was within the area which
now forms Nunavut. Nunavut government officials contacted to date are not aware of any
existing flood risk mapping in the Nunavut territory.
Unique Challenges
Climate change is a key challenge in Nunavut; resulting in precipitation events, surface run-off
and coastal erosion not previously encountered. Nunavut has extremely limited to no capacity
for undertaking the floodplain mapping tasks including the human resources and a lack of in-house
expertise within the territorial government and local institutions to produce and update
floodplain mapping.
Floodplain Mapping on Aboriginal Lands
In Canada flood plain management essentially falls under the jurisdiction of the provinces, as
they are primarily responsible for water resources and land use matters. In the Yukon and
NWT, land and water management responsibilities have been devolved from the federal
government to the territorial governments. No such devolution of these responsibilities has
occurred in Nunavut.
In addition to the provincial and territorial agreements under that program, the departments
of Environment and Indian and Northern Affairs signed a Memorandum of Understanding
(MOU) in 1985 respecting Flood Risk Mapping of Indian Reserve Lands and Other Lands Set
Aside or Held for Indians. The FDRP archived website states that under this MOU, studies were
conducted to identify priority flood prone areas, and 44 mapping projects were undertaken.
Aboriginal Affairs and Northern Development Canada (AANDC) staff located the FDRP mapping
for four of the 44. All four are in Indian Reserves in Alberta: #6645 - BLOOD 148; #6639 - TSUU
T'INA NATION 145; #6683 - SAWRIDGE 150G; and #6642 - STONEY 142-143-144.

4.0 Expert Comments
Input and opinion was solicited from subject matter experts in all aspects of floodplain
mapping. The approach was to prepare a survey template where opinion was sought in the
broad categories of base mapping, hydrology, hydraulics, governance, and flood risk data and
mapping. The completed surveys are included in the background report, Review of International
and National Flood Mapping Practices, April 2014. The key comments received are summarized
below, and are organized based on the Guiding Principles set out on Page 3. The majority of the
comments refer to improving technical accuracy of mapping and providing added information
to improve overall effectiveness in understanding and managing flood risk.
Technical Accuracy
1. The fact that there is a high degree of uncertainty in all of the steps leading to estimation of
flood risk should be documented and included as part of the presentation of flood risk.
2. Additional streamflow gauging would help with accuracy, particularly in ungauged
watersheds.
3. Standard methods for relating flooding to damages should be updated across Canada.
4. There should be more formal procedures available to complete all steps of the mapping
process.
5. More importance should be placed on both calibration and on-going updates/verification.
6. There should be National Vision and set of standards that would apply across Canada.
7. Floodplain management should move beyond hazard mapping to consider risk to
communities, industry and agriculture.
8. Mapping should be extended along more rivers, particularly through urban areas.
9. Events more severe than the 1:100 year event should be considered in hazard mapping and
flood risk assessment; particularly when one considers both the degree of uncertainty
associated with the estimates and that statistically a 1:100 year event has a 65 percent
chance of occurring in a 100 year period.
10. The capacity for undertaking the floodplain mapping tasks including the human resources
and in-house expertise varies across the country. Certain jurisdictions, particularly NWT
and Nunavut, have limited to no capacity to produce and update floodplain mapping and
have limited to no experience and expertise in the use of the mapping at the community
and territorial levels.

11. The public should have much better access to flood risk information.
Current
12. Across much of Canada there is a need for updated floodplain mapping.
5.0 Status of Floodplain Management in Canada
The development of floodplain mapping, as it is understood today, began in approximately
1975. Currently mapping is available along some 28,000 km of rivers and streams across
Canada. Most of the mapping was initially developed between 1975 and 1996 through the
federal-provincial Flood Damage Reduction Program (FDRP). However with updates and
additional mapping that has been completed since completion of FDRP, approximately half of
the existing mapping was developed after 1996.
This section of the report documents the status of existing mapping across Canada, compares
the existing mapping to standards associated with the National Floodplain Management
Framework, provides a Risk Assessment approach for updating existing mapping, and provides
a guideline cost estimate to complete the update of the mapping.
Collection and Presentation of Existing Mapping
The first task was to compile a database of existing mapping, including any available
information related to the location, age, and scale of the existing mapping. Apart from Ontario,
existing information was collected by contacting each province and territory. Ontario is unique
in that the majority of floodplain mapping is developed and maintained through the 36
Conservation Authorities, with the remainder administered through the Ministry of Natural
Resources.
A map of Canada was developed, viewable through Google Earth, which illustrates all
watercourses that have been mapped. In most cases, the compiled map only illustrates the
sections of the watercourse that have been mapped. In the remaining cases the compiled map
illustrates the horizontal limits of the flood hazard mapping. The map of floodplain limits was
then overlaid on a map of urban boundaries in order to estimate the fraction of the hazard
mapping in each province that is urban.
Summary of Existing Mapping
As noted, floodplain mapping is available for approximately 28,000 km of watercourse across
Canada. Figure 1 presents a graph of the extent of existing mapping based on the year it was
prepared, while Table 1 provides a summary based on 10-year increments. Table 2 summarizes
the mapping available for each Province and Territory, including the fraction that is in urban
areas and the median age of the mapping.

As illustrated by Figure 1, new or updated mapping has been developed each year since 1975.
There have been a couple of periods where the development of new mapping has been most
active; 1985-1990 and 2004-2009. The median age of mapping across Canada is 1996, with 25
percent completed prior to 1987 and 25 percent since 2006.
1800
1600
1400
1200
1000
800
600
400
200
0
Figure 1: Date of Floodplain Mapping
1974 1979 1984 1989 1994 1999 2004 2009 2014
Floodplain Mapping (km)
Year
The extent of mapping in each
province and territory is generally
proportional to the population. Of
the total, 59 percent of existing
floodplain mapping is in Ontario,
21 percent is in Québec, and 10
percent is in British Columbia. The
remaining 10 percent is
distributed across the other provinces and territories. This is because the focus has always
been on preparing mapping for the more populated areas.
TABLE 1: AGE OF EXISTING MAPPING
Period Total (%) Percentile Year Completed
1970-1979 7 25 1987
1980-1989 24 50 1996
1990-1999 22 75 2006
2000-2009 39
2010-2013 8
TOTAL (km) 28,100
Overall approximately 35 percent of the mapping is through urban areas. However the ratio of
mapping that is in urban areas varies widely, from a low of 14 percent in British Columbia to a
midrange of 49 percent in Alberta to a high of 75 percent in Québec.
Although the median age of all mapping in Canada is 18 years (1996), there is also a fair
variability in mapping age. The median age of all mapping in Alberta, Québec and Ontario is
approximately 10 years old, while it is in excess of 20 years old in the remaining jurisdictions.

TABLE 2: MAPPING SUMMARY
Total Length
(km)
Urban
(km)
Rural
(km)
Urban
(%)
Median
age
British Columbia 2,656 369 2,286 14 1989
Alberta
960 472 488 49 2007
Saskatchewan 253 98 155 39 1989
Manitoba
363 126 237 35 1993
Ontario
16,675 4,500 12,175 27 2002
Québec
5,800 4,345 1,450 75 2003
New Brunswick <500 132 368 26 1992
Prince Edward Island <50 25 25 50 --
Nova Scotia <500 132 368 26 1980
Newfoundland and Labrador 228 60 168 26 1990
Yukon
- -- -- -- --
Northwest Territories 110 -- 1101 -- 1986
Nunavut - - - --- --
CANADA 28,100 10,300 17,800 35% 1996
1 mapping centred around remote northern communities
The vast majority of maps were prepared in accordance with FDRP standards or more recent
guidelines such as the Flood Hazard Identification Program Guidelines (Alberta, 2011) or the
Technical Guide – River and Streams Systems: Flooding Hazard Limit (Ontario, 2002). In most
cases the printed scale is 1:2,000 or 1:5,000, however with digital mapping the scale is not as
relevant as in the past.
It is difficult to precisely measure that fraction of the Canadian population living in flood prone
lands that have actually been mapped. The reason that it is difficult is that it is not currently
known how many watercourses in populated areas have not been mapped and, to a certain
extent, the floodplain area is not known until it is mapped. However, it is clear that in some
jurisdictions (including much of Ontario) coverage likely exceeds 95 percent of flood prone
residences. Overall, across Canada it is estimated that approximately 65 percent of residences
located in flood prone areas currently have floodplain mapping coverage. This is based on a
high level review of the extent of unmapped watercourses in populated areas.
Figure 2 provides an estimate of the magnitude of mapping required for each province and
territory to increase coverage across Canada to 95-100 percent of all flood prone residences. It
should be cautioned that the estimate for additional mapping is a very preliminary estimate
and would need to be updated as part of the proposed Risk Assessment. Nevertheless the
information provided can serve as a starting point in understanding the need for additional
mapping. The default increase in mapping was set to 50 percent; however the increase was
refined for provinces and territories where there was a better understanding of future
requirements.

FIGURE 2: MAPPING COVERAGE ACROSS CANADA
Province/Territory
Existing
(km)
Additional
(km)
Bar Chart Showing
Current and Proposed Coverage (%)
0 20 40 60 80 100
British Columbia 2,656 2,650
Alberta 960 770
Saskatchewan 253 125
Manitoba 363 185
Ontario 16,675 500
Quebec 5800 10000
New Brunswick <500 250
Prince Edward Island <50 25
Nova Scotia <500 250
Nfld. & Labrador 228 115
Yukon - 2601
Northwest Territories 1102 30
Nunavut - 1303
Existing
Proposed
Notes
1) Includes flood prone community areas identified for 2014-2015 LiDAR surveying.
2) FDRP mapping that requires updating and verification.
3) Includes mapping for communities subject to coastal and shoreline flooding; estimate based on 25
communities approximately 5+ km/community.
6.0 Comparison of Existing Mapping to Proposed Standards
The following provides a discussion of how current mapping compares to the proposed
mapping standards. For discussion purposes, the comparison is based on the following key
standards:
• Base Mapping.
• Regulatory Event for Flood Hazard Mapping.
• Flood Risk Database.
• Age of Mapping
• Climate Change Adaptation.

National Floodplain Mapping Assessment - Final Report

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