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National Floodplain Mapping
Assessment - Final Report
MMM Group ...
National Floodplain Mapping
Assessment
Final Report
June 2014
National Floodplain Management Framework Page i
Public Safety Canada
Executive Summary
Canada has witnessed a notable i...
National Floodplain Management Framework Page ii
Public Safety Canada
The first step in developing the National Floodpla...
National Floodplain Management Framework Page iii
Public Safety Canada
Accessibility to the User
10. The public should ...
National Floodplain Management Framework Page iv
Public Safety Canada
As a next step it is recommended that a Risk Asses...
National Floodplain Management Framework Page v
Public Safety Canada
There are a several initiatives that are recommende...
National Floodplain Management Framework Page vi
Public Safety Canada
Table of Contents
1.0 Introduction .................
National Floodplain Management Framework Page 1
Public Safety Canada
1.0 Introduction
Canada has witnessed a notable in...
National Floodplain Management Framework Page 2
Public Safety Canada
The Emergency Management Framework (EMF) is a joint...
National Floodplain Management Framework Page 3
Public Safety Canada
The National Floodplain Management Framework addres...
National Floodplain Management Framework Page 4
Public Safety Canada
Effective in Assessing and Managing Risk
Fundament...
National Floodplain Management Framework Page 5
Public Safety Canada
• General - recent initiatives related to updating ...
National Floodplain Management Framework Page 6
Public Safety Canada
Member States are required to undertake a number of...
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Public Safety Canada
information such as hospital and key transportation...
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Public Safety Canada
France
France has floodplain maps for essentially ...
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Public Safety Canada
Access
In Germany some maps are currently availabl...
National Floodplain Management Framework Page 10
Public Safety Canada
Extent of Existing Standards
Currently, there are...
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Public Safety Canada
In addition to the DFE (typically 1:100 year event...
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Public Safety Canada
The CDEM Act is another key piece of legislation f...
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Public Safety Canada
United States of America
Of the nations reviewed,...
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Public Safety Canada
Communities must require that all new construction...
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Public Safety Canada
3. Vertical Basemap Accuracy - There is a trend to...
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Public Safety Canada
Current
10. Climate Change can have a significant...
National Floodplain Management Framework Page 17
Public Safety Canada
During this transition, the Province undertook an ...
National Floodplain Management Framework Page 18
Public Safety Canada
This hazard of alluvial fans and debris flows is u...
National Floodplain Management Framework Page 19
Public Safety Canada
2012. With the recent flooding events of 2013, flo...
National Floodplain Management Framework Page 20
Public Safety Canada
Another hazard that has widespread impacts is high...
National Floodplain Management Framework Page 21
Public Safety Canada
Manitoba
Summary of Current Practices
Since the ...
National Floodplain Management Framework Page 22
Public Safety Canada
Since the majority of the maps are held at individ...
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Public Safety Canada
• Under the two-zone concept the Regulatory flood ...
National Floodplain Management Framework Page 24
Public Safety Canada
Key Map Standards and Regulations
There are curre...
National Floodplain Management Framework Page 25
Public Safety Canada
Nova Scotia
Summary of Current Practices
Floodpl...
National Floodplain Management Framework Page 26
Public Safety Canada
study, a partnership with Natural Resources Canada...
National Floodplain Management Framework Page 27
Public Safety Canada
The creation of a GIS data base is currently in pr...
National Floodplain Management Framework Page 28
Public Safety Canada
Unique Challenges
Challenges facing floodplain ma...
National Floodplain Management Framework Page 29
Public Safety Canada
4.0 Expert Comments
Input and opinion was solicit...
National Floodplain Management Framework Page 30
Public Safety Canada
Accessibility to the User
11. The public should h...
National Floodplain Management Framework Page 31
Public Safety Canada
As illustrated by Figure 1, new or updated mapping...
National Floodplain Management Framework Page 32
Public Safety Canada
TABLE 2: MAPPING SUMMARY
Total Length
(km)
Urba...
National Floodplain Management Framework Page 33
Public Safety Canada
FIGURE 2: MAPPING COVERAGE ACROSS CANADA
Province...
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National Floodplain Mapping Assessment - Final Report

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 was prepared by MMM Group as an initial step in reducing flood risk across Canada.
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Transcripts - National Floodplain Mapping Assessment - Final Report

  • 1. COMMUNITIES TRANSPORTATION BUILDINGS INFRASTRUCTURE National Floodplain Mapping Assessment - Final Report MMM Group Limited June 2014
  • 2. National Floodplain Mapping Assessment Final Report June 2014
  • 3. 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
  • 4. National Floodplain Management Framework Page ii Public Safety Canada 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.
  • 5. National Floodplain Management Framework Page iii Public Safety Canada 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.
  • 6. National Floodplain Management Framework Page iv Public Safety Canada 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.
  • 7. National Floodplain Management Framework Page v Public Safety Canada 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.
  • 8. National Floodplain Management Framework Page vi Public Safety Canada 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
  • 9. National Floodplain Management Framework Page 1 Public Safety Canada 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.
  • 10. National Floodplain Management Framework Page 2 Public Safety Canada 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.
  • 11. National Floodplain Management Framework Page 3 Public Safety Canada 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.
  • 12. National Floodplain Management Framework Page 4 Public Safety Canada Effective in Assessing and Managing Risk 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. Accessibility to the User 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:
  • 13. National Floodplain Management Framework Page 5 Public Safety Canada • 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)
  • 14. National Floodplain Management Framework Page 6 Public Safety Canada 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
  • 15. National Floodplain Management Framework Page 7 Public Safety Canada 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.
  • 16. National Floodplain Management Framework Page 8 Public Safety Canada 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.
  • 17. National Floodplain Management Framework Page 9 Public Safety Canada 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.
  • 18. National Floodplain Management Framework Page 10 Public Safety Canada 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.
  • 19. National Floodplain Management Framework Page 11 Public Safety Canada 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.
  • 20. National Floodplain Management Framework Page 12 Public Safety Canada 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.
  • 21. National Floodplain Management Framework Page 13 Public Safety Canada 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).
  • 22. National Floodplain Management Framework Page 14 Public Safety Canada 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.
  • 23. National Floodplain Management Framework Page 15 Public Safety Canada 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. Effective in Assessing and Managing Risk 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. Accessibility to the User 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.
  • 24. National Floodplain Management Framework Page 16 Public Safety Canada 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.
  • 25. National Floodplain Management Framework Page 17 Public Safety Canada 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.
  • 26. National Floodplain Management Framework Page 18 Public Safety Canada 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 Summary of Current Practices 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
  • 27. National Floodplain Management Framework Page 19 Public Safety Canada 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. Key Map Standards and Regulations 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.
  • 28. National Floodplain Management Framework Page 20 Public Safety Canada 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 Summary of Current Practices 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.
  • 29. National Floodplain Management Framework Page 21 Public Safety Canada Manitoba Summary of Current Practices 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 Summary of Current Practices 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.
  • 30. National Floodplain Management Framework Page 22 Public Safety Canada 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). Key Map Standards and Regulations 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
  • 31. National Floodplain Management Framework Page 23 Public Safety Canada • 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 Summary of Current Practices 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.
  • 32. National Floodplain Management Framework Page 24 Public Safety Canada Key Map Standards and Regulations 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 Summary of Current Practices 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.
  • 33. National Floodplain Management Framework Page 25 Public Safety Canada Nova Scotia Summary of Current Practices 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 Summary of Current Practices 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 Summary of Current Practices 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
  • 34. National Floodplain Management Framework Page 26 Public Safety Canada 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. Key Map Standards and Regulations 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 Summary of Current Practices 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.
  • 35. National Floodplain Management Framework Page 27 Public Safety Canada 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 Summary of Current Practices 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.
  • 36. National Floodplain Management Framework Page 28 Public Safety Canada 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 Summary of Current Practices 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.
  • 37. National Floodplain Management Framework Page 29 Public Safety Canada 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. Effective in Assessing and Managing Risk 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.
  • 38. National Floodplain Management Framework Page 30 Public Safety Canada Accessibility to the User 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.
  • 39. National Floodplain Management Framework Page 31 Public Safety Canada 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.
  • 40. National Floodplain Management Framework Page 32 Public Safety Canada 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.
  • 41. National Floodplain Management Framework Page 33 Public Safety Canada 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.

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