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ICLR Friday Forum: National floodplain mapping framework (Oct 10, 2014)

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On October 10, 2014 ICLR conducted a Friday Forum workshop on the state of floodplain mapping in Canada. Public Safety Canada is the lead federal agency responsible for disaster prevention and mitigation. In response to increases in flood intensity and flood damage over the past number of years, PSC has completed the National Floodplain Mapping Assessment. The Assessment includes three parts: a review of international practices, the state of flood hazard mapping across Canada including the cost of updating the and mapping to proposed standards, and a Framework that established state-of-the-art standards for both the update of flood hazard mapping and the development of national flood risk data base. This presentation focused on the National Floodplain Management Framework including the proposed mapping standards, anticipated implementation steps, and the scope and intent of the flood risk database.

The second half of the presentation focused on recent advancements in effectively defining urban overland flood risk. Urban overland flooding is caused by intense rainfall events in areas where there is insufficient storm sewer system capacity and poorly defined overland flow routes. Currently, across Canada urban areas prone to urban flooding are not generally defined. Moreover, in cases that are known to be flood prone the risk is rarely quantified. By better defining areas at risk, municipalities can focus efforts in effective urban overland flood mitigation.

Workshop leader Tim Mereu, Vice President of MMM Group, has responsibility for Water Resources and Environmental Services. He has thirty years of consulting experience with a focus on water resources, including flood risk management, policy and standards development, master planning, channel restoration, and storm water management. Tim was the Project Manager for the recently completed National Floodplain Mapping Assessment undertaken by Public Safety Canada.

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ICLR Friday Forum: National floodplain mapping framework (Oct 10, 2014)

  1. 1. FLOOD RISK IN CANADA – MOVING FORWARD • NATIONAL FLOODPLAIN MANAGEMENT FRAMEWORK • ADVANCEMENTS IN URBAN FLOODING Institute for Catastrophic Loss Reduction October 10, 2014
  2. 2. OUTLINE OF PRESENTATION ► Flood Risk Primer ► National Floodplain Management Framework ► Urban Overland Flooding
  3. 3. x ► x FLOOD RISK PRIMER Copyright: <a href='http://www.123rf.com/profile_alexmit'>alexmit / 123RF Stock Photo</a> FLOOD RISK PRIMER Copyright: <a href='http://www.123rf.com/profile_tashka'>tashka / 123RF Stock Photo</a>
  4. 4. TYPES OF FLOODING
  5. 5. TYPES OF FLOODING
  6. 6. TYPES OF FLOODING Copyright: <a href='http://www.123rf.com/profile_vicnt'>vicnt / 123RF Stock Photo</a>
  7. 7. TYPES OF FLOODING Copyright: <a href='http://www.123rf.com/profil e_vicnt'>vicnt / 123RF Stock Photo</a>
  8. 8. RIVERINE FLOODING ► Calgary 2013, Toronto 1954, Winnipeg 2011 ► Canada-wide Hazard Mapping ► Until now, Risk not typically defined ► The focus of the new federal flood management initiative
  9. 9. HAZARD MAPPING VERSUS RISK MAPPING Hazard Mapping ► Limits of hazard ► Used for regulating land use in floodplain Risk Mapping and Database ► Frequency, depth, duration ► Consequence
  10. 10. RIVERINE FLOODING - ICE WINNIPEG 1926
  11. 11. URBAN OVERLAND FLOODING ► Two types: ► Urban only(pluvial) ► Riverine/urban hybrid ► Typically caused by intense summer storms ► Capacity of storm sewers and road network is exceeded
  12. 12. BASEMENT FLOODING ► Generally caused by sewer backup ► Risk can be determined but costly to assess ► Can be remedied through conveyance improvements and disconnects Copyright: <a href='http://www.123rf.com/profile_vicnt'>vicnt / 123RF Stock Photo</a>
  13. 13. COASTAL FLOODING ► Generally caused by high winds, but along lake shores can also be caused by high water levels ► Shoreline hazard mapping existing for many lakes across Canada but relatively few coastlines
  14. 14. KEY STEPS IN CREATING FLOOD HAZARD MAPPING • Base Mapping • Hydrology – the estimate of peak flows • Hydraulics – the calculation of flood elevations • Flood Plain Mapping – Mapping of lines and elevations 14
  15. 15. TYPICAL FLOOD HAZARD MAP
  16. 16. TYPICAL FLOOD HAZARD MAP
  17. 17. REGULATING FLOOD PLAINS ACROSS CANADA
  18. 18. Floodway and Flood Fringe Development Tim 18
  19. 19. HOW ACCURATE IS CURRENT MAPPING? 19
  20. 20. How Often will it Flood? SINGLE SITE Return Period (years) Annual Probability (%) Probability in next 10-years Probability in next 50-years Probability in next 100-years Probability in next 250-years 2 50% 100% 100% 100% 100% 25 4% 34% 87% 98% 100% 100 1% 10% 39% 63% 92% 500 0.2% 2% 10% 18% 39% 1000 0.1% 1% 5% 10% 22% 10 INDEPENDENT SITES Return Period (years) Annual Probability (%) Probability in next 10-years Probability in next 50-years Probability in next 100-years Probability in next 250-years 2 50% 100% 100% 100% 100% 25 4% 98% 100% 100% 100% 100 1% 63% 99% 100% 100% 500 0.2% 18% 63% 86% 99% 1000 0.1% 10% 39% 63% 92% 20
  21. 21. National Floodplain Management Framework Will serve as a guiding document in managing and reducing flood risk across Canada through the development of state-of-the art flood risk mapping. Copyright: <a href='http://www.123rf.com/profile_winnond'>winnond / 123RF Stock Photo</a>
  22. 22. NATIONAL FLOODPLAIN MANAGEMENT FRAMEWORK ► Project Scope ► Project Rationale ► Key study tasks ► Findings and Recommendations ► Next Steps
  23. 23. PROJECT SCOPE ► Review of International and Provincial Best Practices
  24. 24. PROJECT SCOPE ► Review of International and Provincial Best Practices ► Assess state of Mapping across Canada
  25. 25. PROJECT SCOPE ► Review of International and Provincial Best Practices ► Assess state of Mapping across Canada ► Recommend Standards Framework
  26. 26. PROJECT SCOPE ► Review of International and Provincial Best Practices ► Assess state of Mapping across Canada ► Recommend Standards Framework ► Identify implementation requirements including cost
  27. 27. National Floodplain Management Framework PROJECT RATIONALE Copyright: <a href='http://www.123rf.com/profile_winnond'>winnond / 123RF Stock Photo</a>
  28. 28. PROJECT RATIONALE ► Notable increase in flooding in the past decade with annual damages exceeding $1 billion $$ $$
  29. 29. PROJECT RATIONALE ► Notable increase in flooding in the past decade with annual damages exceeding $1 billion ► No national initiative since completion of FDRP in 1995
  30. 30. PROJECT RATIONALE ► Notable increase in flooding in the past decade with annual damages exceeding $1 billion ► No national initiative since completion of FDRP in 1995 ► Public Safety Canada is the lead federal agency responsible for national disaster mitigation
  31. 31. PROJECT RATIONALE ► Notable increase in flooding in the past decade with annual damages exceeding $1 billion ► No national initiative since completion of FDRP in 1995 ► Public Safety Canada is the lead federal agency responsible for national disaster mitigation ► There is no residential overland flood insurance program in Canada No Insurance! Are you kidding me!!!
  32. 32. National Floodplain Management Framework FUNDAMENTAL CHANGE Copyright: <a href='http://www.123rf.com/profile_winnond'>winnond / 123RF Stock Photo</a>
  33. 33. RECOMMENDING FUNDAMENTAL CHANGES ► Continue to develop Flood Hazard Maps ► Will be supplemented by a Flood Risk Data Base and Flood Risk Mapping ► Nationally coordinated data base that is accessible
  34. 34. RECOMMENDING FUNDAMENTAL CHANGES ► Continue to develop Flood Hazard Maps ► Will be supplemented by a Flood Risk Data Base and Flood Risk Mapping ► Nationally coordinated data base that is accessible Will lead to: ► Reduction in flood damage ► Availability of flood insurance Where is my Broker when I need him !!
  35. 35. National Floodplain Management Framework GUIDING PRINCIPLES Copyright: <a href='http://www.123rf.com/profile_winnond'>winnond / 123RF Stock Photo</a>
  36. 36. GUIDING PRINCIPLES ► Technical Accuracy ► Effective in assessing and Managing Risk ► Accessible to the User ► Information is Current
  37. 37. Technical Accuracy And Hurricane Hazel?
  38. 38. GUIDING PRINCIPLES ► Technical Accuracy ► Effective in Assessing and Managing Risk ► Accessible to the User ► Information is Current
  39. 39. GUIDING PRINCIPLES ► Technical Accuracy ► Effective in assessing and Managing Risk ► Accessible to the User ► Information is Current
  40. 40. GUIDING PRINCIPLES ► Technical Accuracy ► Effective in assessing and Managing Risk ► Accessible to the User ► Information is Current
  41. 41. National Floodplain Management Framework INTERNATIONAL Copyright: <a href='http://www.123rf.com/profile_winnond'>winnond / 123RF Stock Photo</a>
  42. 42. INTERNATIONAL BEST PRACTICES What can we learn from practices in other countries, most specifically: ► EU: France, Switzerland, Germany ► United Kingdom ► United States ► Australia ► New Zealand
  43. 43. INTERNATIONAL BEST PRACTICES What we learned ► 20 years ago we were among the leaders but we have been surpassed in some respects ► National leadership ► More emphasis on integrating hazard mapping and flood risk data ► Accessibility ► Hurricane Hazel as a Regulatory event is the mist stringent noted
  44. 44. National Floodplain Management Framework VARIATIONS ACROSS CANADA Copyright: <a href='http://www.123rf.com/profile_winnond'>winnond / 123RF Stock Photo</a>
  45. 45. VARIATIONS ACROSS CANADA Differences: ► Regulatory events Copyright: <a href='http://www.123rf.com/profile_alexmit'>alexmit / 123RF Stock Photo</a>
  46. 46. VARIATIONS ACROSS CANADA Differences: ► Regulatory events ► Governance models Copyright: <a href='http://www.123rf.com/profile_iqoncept'>iqoncept / 123RF Stock Photo</a>
  47. 47. VARIATIONS ACROSS CANADA Differences: ► Regulatory events ► Governance models ► Approach to building in flood plains including SPAs Copyright: <a href='http://www.123rf.com/profile_alexmit'>alexmit / 123RF Stock Photo</a>
  48. 48. VARIATIONS ACROSS CANADA Differences: ► Regulatory events ► Governance models ► Approach to building in floodplains including SPAs ► Challenges
  49. 49. National Floodplain Management Framework EXPERT OPINION Copyright: <a href='http://www.123rf.com/profile_winnond'>winnond / 123RF Stock Photo</a>
  50. 50. OPINIONS OF PROVINCIAL EXPERTS Copyright: <a href='http://www.123rf.com/profile_snake3d'>snake3d / 123RF Stock Photo</a>
  51. 51. OPINIONS OF PROVINCIAL EXPERTS Copyright: <a href='http://www.123rf.com/profile_snake3d'>snake3d / 123RF Stock Photo</a>
  52. 52. OPINIONS OF PROVINCIAL EXPERTS ► Move beyond hazard mapping to consider risk ► The 1:100-year event is not sufficient ► Expand and Update mapping ► Address governance and capacity limitations ► Accessibility
  53. 53. OPINIONS OF PROVINCIAL EXPERTS ► Move beyond hazard mapping to consider risk ► The 1:100-year event is not sufficient ► Expand and Update mapping ► Address governance and capacity limitations ► Accessibility
  54. 54. OPINIONS OF PROVINCIAL EXPERTS ► Move beyond hazard mapping to consider risk ► The 1:100-year event is not sufficient ► Expand and Update mapping ► Address governance and capacity limitations ► Accessibility
  55. 55. OPINIONS OF PROVINCIAL EXPERTS ► Move beyond hazard mapping to consider risk ► The 1:100-year event is not sufficient ► Expand and Update mapping ► Address governance and capacity limitations ► Accessibility
  56. 56. OPINIONS OF PROVINCIAL EXPERTS ► Move beyond hazard mapping to consider risk ► The 1:100-year event is not sufficient ► Expand and Update mapping ► Address governance and capacity limitations ► Accessibility
  57. 57. National Floodplain Management Framework STATUS OF MAPPING Copyright: <a href='http://www.123rf.com/profile_winnond'>winnond / 123RF Stock Photo</a>
  58. 58. STATUS OF MAPPING ACROSS CANADA 1800 1600 1400 1200 1000 800 600 400 200 0 Date of Floodplain Mapping 1974 1979 1984 1989 1994 1999 2004 2009 2014 Floodplain Mapping (km) Year
  59. 59. STATUS OF MAPPING ACROSS CANADA 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
  60. 60. STATUS OF MAPPING ACROSS 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 Quebec 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
  61. 61. 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 2650 Alberta 960 770 Saskatchewan 253 125 Manitoba 363 185 Ontario 16,750 500 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 TOTAL 28,100 15,300 Existing Proposed
  62. 62. National Floodplain Management Framework THE FRAMEWORK Copyright: <a href='http://www.123rf.com/profile_winnond'>winnond / 123RF Stock Photo</a>
  63. 63. FRAMEWORK SCOPE Framework Scope: Guidelines Identifies purpose and general content Performance Standards Identifies key standards that help define risk Technical Standards Recommends proposed standards that contribute to accuracy Initiatives Identifies purpose and general content
  64. 64. GUIDELINE DOCUMENTS ► Base Mapping and Field Survey ► Hydrology ► Hydraulic Analysis ► Coastal and Shoreline Flooding ► Policy Framework ► Flood Risk Assessment and Mapping ► Geo-referenced Database and National Portal
  65. 65. SAMPLE STANDARDS ► Base Mapping ► Vertical accuracy of 0.15 m ► Hydrology ► Estimate flow rated for 1:2 to 1:1,000 years ► Policy Framework ► Minimum Regulatory event should be 1:350 year event ► Minimum Floodway return period should be 1:50 year event
  66. 66. National Floodplain Management Framework NEXT STEPS Copyright: <a href='http://www.123rf.com/profile_winnond'>winnond / 123RF Stock Photo</a>
  67. 67. NEXT STEPS ► Money ► Complete a National Risk Assessment to help establish mapping priorities ► Develop Guidelines and refine the Technical Standards ► Develop Framework for the Flood Risk Database ► Determine the delivery model for preparing mapping and the data base ► Prepare Federal-Provincial/Territorial Agreements
  68. 68. NEXT STEPS ► Money ► Complete a National Risk Assessment to help establish mapping priorities ► Develop Guidelines and refine the Technical Standards ► Develop Framework for the Flood Risk Database ► Determine the delivery model for preparing mapping and the data base ► Prepare Federal-Provincial/Territorial Agreements
  69. 69. NEXT STEPS ► Money ► Complete a National Risk Assessment to help establish mapping priorities ► Develop Guidelines and refine the Technical Standards ► Develop Framework for the Flood Risk Database ► Determine the delivery model for preparing mapping and the data base ► Prepare Federal-Provincial/Territorial Agreements
  70. 70. NEXT STEPS ► Money ► Complete a National Risk Assessment to help establish mapping priorities ► Develop Guidelines and refine the Technical Standards ► Develop Framework for the Flood Risk Database ► Determine the delivery model for preparing mapping and the data base ► Prepare Federal-Provincial/Territorial Agreements
  71. 71. NEXT STEPS ► Money ► Complete a National Risk Assessment to help establish mapping priorities ► Develop Guidelines and refine the Technical Standards ► Develop Framework for the Flood Risk Database ► Determine the delivery model for preparing mapping and the data base ► Prepare Federal-Provincial/Territorial Agreements
  72. 72. NEXT STEPS ► Money ► Complete a National Risk Assessment to help establish mapping priorities ► Develop Guidelines and refine the Technical Standards ► Develop Framework for the Flood Risk Database ► Determine the delivery model for preparing mapping and the data base ► Prepare Federal-Provincial/Territorial Agreements
  73. 73. x ► x URBAN OVERLAND FLOODING Copyright: <a href='http://www.123rf.com/profile_alexmit'>alexmit / 123RF Stock Photo</a>
  74. 74. URBAN OVERLAND FLOODING ► Review Types ► Example of hybrid flooding ► Advances in assessing urban overland flooding
  75. 75. URBAN OVERLAND FLOODING ► Two types: ► Pure urban ► Riverine/urban hybrid ► Typically caused by intense summer storms and poorly defined overland flow routes (pre 1975 in Ontario)
  76. 76. URBAN OVERLAND FLOODING ► Minor/Major design concept significantly reduces risk ► Flood prone areas rarely defined
  77. 77. HYBRID RIVERINE/URBAN OVERLAND FLOODING Reasons flood prone areas rarely defined ► Technology to assess (1D versus 2D models) ► Relative priority ► Governance ► Frequency
  78. 78. HYBRID RIVERINE/URBAN OVERLAND FLOODING Reasons flood prone areas rarely defined ► Technology to assess (1D versus 2D models) ► Relative priority ► Governance ► Frequency
  79. 79. HYBRID RIVERINE/URBAN OVERLAND FLOODING Reasons flood prone areas rarely defined ► Technology to assess (1D versus 2D models) ► Relative priority ► Governance ► Frequency
  80. 80. ASSESSING URBAN OVERLAND FLOODING ► Topographic Map Review ► Complex Modelling ► Screening Method
  81. 81. OVERLAND FLOODING – Topographic Map Review ► Primary areas of concern can be identified ► Difficult to define risk or extent of flooding
  82. 82. OVERLAND FLOODING – Complex modelling ► Simultaneous modelling of runoff, sewer flow and overland flow ► Data and Labour Intensive ► Provides understanding of risk and can be used for assessing mitigation measures
  83. 83. OVERLAND FLOODING – Screening Methods ► Use to screen areas that may be flood prone ► Effectiveness a function of base mapping accuracy ► Provides understanding of risk and can be used for assessing mitigation measures ► Option of applying Complex Modelling for key areas of concern
  84. 84. Example: Flood Depths based on Complex Modelling
  85. 85. Example: Flood Depths based on Screening Method
  86. 86. Example: Flood Depths based on Screening Method
  87. 87. Copyright: <a href='http://www.123rf.com/profile_winnond'>winnond / 123RF Stock Photo</a> Questions? Tim Mereu mereut@mmm.ca

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