Infrastructure Resiliency and Adaptation for Climate Change and Today’s Extremes
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OWWA/WEAO Joint Climate Change Committee Seminar, Climate Change and Infrastructure Design, Hitting a Moving Target, Mississauga, Ontario, November 16, 2017
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Infrastructure Resiliency and Adaptation for Climate Change and Today’s Extremes
- 1. OWWA/WEAO Joint Climate Change Committee Climate Change and Infrastructure Design Hitting a Moving Target Infrastructure Resiliency and Adaptation for Climate Change and Today’s Extremes Robert J. Muir, M.A.Sc., P.Eng. Manager, Stormwater City of Markham November 16, 2017 - Mississauga, Ontario 1
- 2. Crystal Ball or Rear View Mirror What do you really need for extreme weather adaption? 2
- 3. If “Weather Zoltar” Predicted Future IDF, … does it make a ‘BIG’ difference to your adaptation priorities ? If I had a Weather oltar – short Story. 3
- 4. We have always had flooding Engineers don’t let that stop them in in their quests … 4
- 5. Is predicting future weather a priority ? Or understanding existing risks? (like repeated operational ones) http://http://www.cityfloodmap.com/2015/12/toronto-go-train-flood-avoidable-july-8.html 5
- 6. Toronto Island flooding a new normal ? Or an old extreme ? 2017 1973 6
- 7. data shows mostly an old extreme http://www.cityfloodmap.com/2017/09/toronto-island-flooding-2017-were-lake.html 74 74.2 74.4 74.6 74.8 75 75.2 75.4 75.6 75.8 1915 1925 1935 1945 1955 1965 1975 1985 1995 2005 2015 MonthlyLevel(m) Year Lake Ontario Historical May - August Levels May Average August Average Source: 1918-2016 http://www.tides.gc.ca/C&A/network_means-eng.html 2017 http://tides-marees.gc.ca/C&A/pdf/Bulletin1708.pdf May 5 cm above record August not a record 7
- 8. Do roadways and basements flood due to climate change factors ? Or old intrinsic design limitations? 2017 1962 8
- 9. Climate Change or ‘Hydrology Change’? http://www.cityfloodmap.com/2016/03/lost-rivers-newtonbrook-tributary.html 9
- 10. Climate Change or ‘Hydrology Change’? http://www.cityfloodmap.com/2016/03/lost-rivers-newtonbrook-tributary.html 10
- 11. Hydraulic Design Limitations ‘Lost Rivers’ = 3x more insurance claims http://www.cityfloodmap.com/2016/03/lost-rivers-newtonbrook-tributary.html 11
- 12. Hydraulic Design Limitations ‘Lost Rivers’ = 3x more insurance claims http://www.cityfloodmap.com/2016/03/lost-rivers-newtonbrook-tributary.html 12
- 13. Higher Imperviousness = Higher Runoff Risks http://www.cityfloodmap.com/2016/08/urbanization-and-runoff-explain.html 13
- 14. Expanded Urban Areas (Pink) … +1000 % in Rouge Watershed since 60’s http://www.cityfloodmap.com/2016/08/land-use-change-drives-urban-flood-risk.html 14
- 15. Expanded Urban Areas (Pink) … +1000 % in Rouge Watershed since 60’s http://www.cityfloodmap.com/2016/08/land-use-change-drives-urban-flood-risk.html 15
- 16. Expanded Urban Areas (Pink) … +1000 % in Rouge Watershed since 60’s http://www.cityfloodmap.com/2016/08/land-use-change-drives-urban-flood-risk.html 16
- 17. Expanded Urban Areas (Pink) … +1000 % in Rouge Watershed since 60’s http://www.cityfloodmap.com/2016/08/land-use-change-drives-urban-flood-risk.html 17
- 18. Expanded Urban Areas (Pink) … +1000 % in Rouge Watershed since 60’s http://www.cityfloodmap.com/2016/08/land-use-change-drives-urban-flood-risk.html 18
- 19. Urban ‘Pink Splat’… like Cat in the Hat … don’t think we’ll get old hydrology back. 19
- 20. Given known design limitations and significant, quantifiable hydrology stresses affecting urban flooding …. 20
- 21. .. should we “Blame it on the Rain” like Milli Vanilli did ? 21
- 22. or critically assess local rain data trends? http://www.cityfloodmap.com/2015/12/trends-in-canadian-shortduration.html 22
- 23. … but “What about 2005 & 2013…” ? … the storms were extreme !” Finch 2005 Ferarri 2013 23
- 24. 2013 was a record for all “July 8’s” .. but we do not design infrastructure for particular calendar days. 20 40 60 80 100 120 140 1945 1955 1965 1975 1985 1995 2005 2015 2025 MaximumRainfallDepth(mm) Pearson Airport Maximum Daily Rainfall 1950 - 2016 http://www.cityfloodmap.com/2016/01/toronto-climate-change-extreme-rainfall.html http://www.cityfloodmap.com/2015/11/thinking-fast-and-slow-about-extreme.html 24
- 25. … but “IBC says 40 year storms are happening every 6 years !!!!!!!!!” … is an “Insurance Fact”! 25
- 26. Telling the Weather Story - Gordon McBean - Empire Club presentation - YouTube http://www.slideshare.net/RobertMuir3/storm-intensity-not-increasing-factual-review-of-engineering-datasets Actually, not a fact … .. confused prediction with past data. 26
- 27. Test : Infographics or Data … can you tell the difference? Environmental Commissioner Engineering Climate Datasets v2.3 27
- 28. Southern ON Extreme Rain Trends Decreasing http://www.cityfloodmap.com/2016/01/climate-change-ontario-short-duration.html Significant Decr. Decrease Increase Significant Incr. Source: Environment Canada Engineering Climate Dataset ftp://ftp.tor.ec.gc.ca/Pub/Engineering_Climate_Dataset/IDF/ Idf_v2-3_2014_12_21_trends.txt in IDF_Additional_Additionnel_v2.30.zip 28
- 29. Toronto IDF Intensities Decreasing • As annual maximum values drop, extreme IDF intensities decrease too. • Toronto City “Bloor Street” trends are lower for all durations and for all return periods. http://www.cityfloodmap.com/2016/01/toronto-climate-change-extreme-rainfall.html www.cityfloodmap.com Source: Environment Canada Engineering Climate Dataset ftp://ftp.tor.ec.gc.ca/Pub/Engineering_Climate_Dataset/IDF/ Up to 2007 per Dataset v2.3, to 2003 per Dataset v1, to 1990 per hardcopy records CityFloodMap.Com, 2016 29
- 30. Mississauga IDF Intensities Decreasing • Mississauga Airport 5-15 min. intensities decreasing for all return periods. • 24 hour trends are downward despite July 8, 2013 storm. 30
- 31. Southern ON Extreme Rain Trends Decreasing http://www.cityfloodmap.com/2017/11/less-extreme-short-duration-rainfall-in.html 31 http://www.cityfloodmap.com/2017/09/less-extreme-ontario-rainfall.html http://guelph.ca/wp-content/uploads/SMMP-Appendix_E_Combined_IDF_Report.pdf https://drive.google.com/open?id=1Gxmg8gtkzZuv-ZqiqYpc3tQ9r-Ie1v1p
- 32. Canada-wide “lack of a detectable trend signal”, some regional decreases. http://www.tandfonline.com/doi/abs/10.1080/07055900.2014.969677?journalCode=tato20 32
- 33. “Rear View Mirror” data says: Old standards were sometimes a ‘wreck’ Hydrology changes have ‘monster’ impact Rain intensity change was a ‘yappy puppy’ 33
- 34. Has rainfall increased with temperatures? .. no, research at MIT/Columbia and U. of Western show some opposite trends. http://www.ldeo.columbia.edu/~clepore/publications_pdf/grl52319.pdf https://www.slideshare.net/glennmcgillivray/iclr-friday-forum-updating-idf-curves-for-future-climate-march-24-2017 Decreases above 5 degrees C. Clausius-Clapeyron theory has not been observed. ‘Flat’ trends compared to theory. http://www.cityfloodmap.com/2017/06/does-higher-temperature-increase-rain.html 34
- 35. What and where do we need to adapt for tomorrow’s expected extremes? … same as for “design standard adaptation” for yesterday’s & today’s extremes. 35
- 36. • Toronto flood density varies according to design standards / age of servicing, “CSO relief”. • Overland risks increase basement back-up risks. Toronto Adaptation Priority is Old Partially Separated Sewer Service Areas – increased capacity needed. Toronto Basement Flood Reports May 2000, August 2005, July 2013 & Age of Watermain Construction (Estimated Era of Drainage Design Standards) © CityFloodMap.com 36
- 37. Cities must focus on areas with overland flow limitations too (these drive many flood reports and claims). <- Not in these areas …. … but in these overland flow issue areas beyond valleys. 37
- 38. Why focus beyond valleys ? … because flood records show this is the priority. https://www.slideshare.net/RobertMuir3/urban-flood-risk-from-flood-plains-to-floor-drains 38
- 39. August 19, 2005 Storm - Percentage of Properties Flooded Markham Adaptation Priorities are Pre 1980’s Areas Pre 1980 1.0 % Flooded Post 1980 0.15 % Flooded * Considers all properties city-wide (storm intensity was high across the majority of the City). Standard Adaptation: downspout disconnection, MH sealing, storm capacity upgrades (limit sanitary inflows), backwater valves, etc. 39
- 40. July 16, 2017 Storm - Percentage of Properties Flooded July 2017 Storm Confirmed Design Standard Adaptation Priorities Pre 1980 2.4 % Flooded 1980 - 1990 0.6% Flooded Post 1990 0.04% Flooded • Considers north-east quadrant of the City where the storm intensities were highest (25,527 properties). Post-1990 servicing flooded 7 of 15,889; 1980-1900 servicing flooded 21 of 3366; pre-1980 servicing flooded 151 of 6272. Most effective to focus on these old areas – new ones are resilient to 2095. See CWWA 2017 future stress test analyses. 40
- 41. Future IDF ‘Stress Test’ – City-wide Sanitary System • Future U. of R. A1B 50% 2065-2095 scenario. • Chicago Storm - increase IDF values by 30% over 2 hrs. • Use calibrated /monitored values. • Apply calibrated inflow & infiltration response. • Dynamic / gradually varied flow model (InfoWorks). • Sanitary system HGL less than 2.0 m below grade (near basement). IDF Data Hyetograph Selection Dry Weather Sanitary Flow I&I Transformation (Extraneous Flow) Hydraulic Performance / Freeboard Damages / Risk – Assess Need for Adaptation Today’s IDF Future IDF Sewer Surcharge (%) 7.4 12.1 + 64 % MH Surcharge (%) 1.8 3.5 + 94% Impacts in old subdivisions, new subdivisions resilient Most Critical ± 2000 % Risk Less Critical 41
- 42. Fully-Separated Sanitary (post 1980’s) Not Stressed with Future IDF (High Resiliency) Shallow Sewer (limited freeboard for dry weather) Existing 100-Year IDF - MH Freeboard < 2 m Future 100-Year IDF – MH Freeboard <2 mToday’s IDF Future IDF Freeboard < 2 m = Back-up Risk Impacts in old subdivisions with existing limitations Pre 1980 80’s 90’s 42
- 43. 0 50 100 150 200 250 300 0 50 100 150 200 250 300 350 400 450 500 RainfallIntensity(mm/hr) Time (minutes) Markham Storm (3 Hr AES) 100 Year TRCA Storm (AES 12 Hr) 100 Year 100-Year Storm Hyetographs Are Highly Variable / Uncertain Risk “Gap” Sanitary sewer surcharge and flood risk vary by 2000% based on changes in storm pattern. 43
- 44. What is the role of knowing the future ? 44
- 45. Markham Class EA Future Adaptation Requirements 200 210 220 230 240 250 260 270 280 290 300 1975 1995 2015 2035 2055 2075 2095 45 Buttonville Airport (Markham) Pearson Airport (Mississauga) Observed Bloor Street (Toronto) Markham Design Standard RainIntensitymm/hr(5minute100-year)
- 46. Markham Class EA Future Adaptation Requirements 200 210 220 230 240 250 260 270 280 290 300 1975 1995 2015 2035 2055 2075 2095 Buttonville Airport (Markham) Pearson Airport (Mississauga) Observed Bloor Street (Toronto) Predicted Markham Design Standard Future Safety Factors Future Stress Test RainIntensitymm/hr(5minute100-year) 46
- 47. Future IDF is a Moving Target 200 210 220 230 240 250 260 270 280 290 300 1975 1995 2015 2035 2055 2075 2095 Buttonville Airport (Markham) Pearson Airport (Mississauga) Observed Bloor Street (Toronto) Predicted Markham Design Standard RainIntensitymm/hr(5minute100-year) 47
- 48. 0 50 100 150 200 250 300 350 400 1975 1995 2015 2035 2055 2075 2095 Post 80’s systems are resilient for 20 – 30 % higher IDF (storm & sanitary networks) So focus on known problems & priorities to adapt Observed Predicted Today’s Standard RainIntensitymm/hr(5minute100-year) “Design Standard Adaptation” in old areas. Requires 250% or more conveyance capacity.Pre 80’s Standard 48
- 49. Conclusions • There are significant industry gaps in understanding: • Past extreme rainfall trends (decreasing in southern Ontario) • Key quantifiable drivers for flood risk reduction weather vs. hydrology change weather vs. hydraulics constraints (overland design) • System vulnerability varies with design standards: • Post 1990 standards significantly decreased flood risk to 1/60th of pre-1980’s standards risks. • Historical land use practices with limited design standards drive specific, local adaptation priorities (no generic fixes). • “Design Standard Adaptation” adds resiliency • Addressing older system limitations provides future climate adaptation co-benefit … regardless of future rainfall IDF (uncertain & not converging). • Highest incremental benefits for infrastructure improvements to older systems – marginal benefits decrease at higher levels.49
- 50. Thank You Questions ? More Rob : Blog: www.CityFloodMap.com Podcast: Open During Construction on iTunes Twitter: @RobertMuir_PEng More City of Markham : Web: www.markham.ca Twitter: @CityofMarkham 50
Notes de l'éditeur
- Thank you for sticking around for the last presentation – good things come to those who wait. Hopefully a fresh persepctive.
- Crystal ball or rear view mirror. What do you really need for extreme weather adaptation? Is knowing future extreme weather patterns essential to guide where and how much to adapt – what we do with infrastructure - or can we look back to see the risks factors to address?
- Make a wish. If you had a Weather Zoltar arcade machine to predict future intensity duration IDF statistics. Put in a quarter, and our comes future IDF. If you had such as machine, does its output make a Big difference in how your city should adaptation? Some cities have put a quarter – of a million dollars - into similar machines.
- If we look to the past, we see we have always had extreme events and flooding. Engineers can’t predict the details but that doesn’t stop them in their everyday quests. Like getting to the beer store. Or upgrading infrastructure.
- Is predicting future weather even a priority? Lets say to address catastrophes like the flooded GO Train in 2013. Or could we manage some existing risks by critically understanding operational risks with today’s weather. Sometimes history is just repeating itself and weather is not the key. The GO Train has been flooding right after the Richmond Hill line started in the late 1970’s.
- Toronto Island Flooding, is that a new normal? Or and old extreme? To answer this, we really have to look at data instead of just exercising our availability biases. Anyone remember the flood of 1973?
- Or the flood of 52 or 47 ? Probably not – I see a crowd of young good looking people. For you folks, data shows 2017 – while above average - was just centimeters above previous extremes. Make you wonder why evictions from this known hazard zone were stalled in the 80’s.
- Do roadways and basements flood due to climate change factors ? That is Windsor in Are effective CSO controls keeping too much wet weather flow in the pipes for extreme events, is the 100 year floodplain level of service enough Essex County?
- What have we had more of recently – climate change or hydrology change. This shows the Newtonbrook area in North York It developed through the 40s 50s and 60s and upstream in Vaughan through the 80’s – so parts of our cities have not really been subject to full hydrology runoff stresses until recently – this area was flooding by the 80’s.
- What have we had more of recently – climate change or hydrology change. This shows the Newtonbrook area in North York It developed through the 40s 50s and 60s and upstream in Vaughan through the 80’s – so parts of our cities have not really been subject to full hydrology runoff stresses until recently – this area was flooding by the 80’s.
- And some systems are designed to flood occasionally because of lack of overland flow path. We only started that in the late 1970’s. So we have inherited systems with ‘Lost Rivers’ and overland flow risks. This maps shows the overland flow spread areas, and reported flooding. One keen insurance company found 3 time the claims in 2013 in overland flow zones.
- And some systems are designed to flood occasionally because of lack of overland flow path. We only started that in the late 1970’s. So we have inherited systems with ‘Lost Rivers’ and overland flow risks. This maps shows the overland flow spread areas, and reported flooding. One keen insurance company found 3 time the claims in 2013 in overland flow zones.
- And we have more than doubled the hard surfaces in our subdivisions. That drives higher flood risks in our watersheds. Intensification has doubled impervious due to infills in one Markham neighbourhood since the 50’s – Bayview Glen.
- And urbanization change has occurred at a considerable, measurable pace with almost 1000% more urban are in the Rouge Watershed from the mid 60’s to the 1999 – other areas that have experience significant flooding in the GTA has experienced the same.
- And urbanization change has occurred at a considerable, measurable pace with almost 1000% more urban are in the Rouge Watershed from the mid 60’s to the 1999 – other areas that have experience significant flooding in the GTA has experienced the same.
- And urbanization change has occurred at a considerable, measurable pace with almost 1000% more urban are in the Rouge Watershed from the mid 60’s to the 1999 – other areas that have experience significant flooding in the GTA has experienced the same.
- And urbanization change has occurred at a considerable, measurable pace with almost 1000% more urban are in the Rouge Watershed from the mid 60’s to the 1999 – other areas that have experience significant flooding in the GTA has experienced the same.
- And urbanization change has occurred at a considerable, measurable pace with almost 1000% more urban are in the Rouge Watershed from the mid 60’s to the 1999 – other areas that have experience significant flooding in the GTA has experienced the same.
- So this pink urban splat .. looks like Cat in the Hat. And I don’t think we’ll get old hydrology back. Given known design limitations and hydrology stresses
- Given known design limitations and hydrology stresses ….
- Or critically assess local data for trends. These annual maximum rain trends in Toronto are from Environment Canada’s Engineering Climate Dataset. Toronto long term trends are down.
- But Rob! What about 2005 and 2013 .. those storms were extreme. We lost Finch. I lost my Ferrari !!!
- 2013 had a record for July 8ths definitely – but we do not design infrastructure for particular calendar days. Check out the data on my blog at the first link. And at the second link I breakdown how the media takes short cuts when reporting on extremes.
- But Rob! The insurance Bureau of Canada says 40 year storms are happening every 6 years. Telling the weather story says this is happening in some part of Canada.
- Actually not a fact at all – this 40 to 6 year frequency shift was based on an arbitrary 1 standard deviation shift in a standard normal bell curve as presented at the Empire Club of Canada by the author. I am bound by confidentiality on 3 files settled through advertising standards Canada using this inaccutate fact in advertising – so don’t ask me any questions on the advertising. But lets look at the data I shared.
- An I need to test you to see if you can tell the difference between infographics and data. Which one of these is data. OK lets look at that good stuff for southern Ontario.
- Southern Ontario extreme rain trends are decreasing. What would make me say such as silly thing. Answer- The Engineering Climate Datasets. More significant decreases than increases and more statistically significant decreases. Follow the links. Get the data of check out the review on my blog.
- As observed rainfall decreases so do extreme value statistics – IDF curve intensities. This is the Toronto Bloor Street trend – look at the bottom row, the 100 year rain intensity, its down over 5% since I graduated.
- Mississauga IDF intensities down too even considering 2013.
- This is repeated in countless studies from the University of Waterloo, University of Guelph, professional studies for cities.
- And Canada-wide – in the rear view
- Has rainfall increased with temperatures? No research has shown sometimes the opposite – so when someone says 1 decrees Celsius equals 7% more water vapour so we must get more rain, they are referring to the Clausius-Claperon equation – and obervations show this has not happened. So fundamentally it makes sense that we may not see rain changes like temperatures changes.
- What and where do we need to adapt for tomorrow’s expected extremes? … same as for “design standard adaptation” for yesterday’s and today’s extremes. I’ll show you the Markham example.
- Based on spatial analysis of flood reports from 2000, 2005 and 2013 in Toronto. This adaptation is needed most in partially separated sewer service areas with no CSO relief.
- So in Markham in 2005 most flooding was in old areas – pre 1980’s areas with limited design standards - so we are doing the most cost effective adaptation measures first. Downspout disconnection. And storm capacity upgrades. We are also starting a backwater valve program and looking at sanitary capacity upgrades because we cannot control all the I&I.
- And this summers storms confirmed our priorities. New subdivisions post 1990’s are resilient already. I also presented the future resiliency of storm and sanitary sewer systems at CWWA last week.
- If we use a different hyetograph, like Toronto’s May 200 storm or Ottawa’s 2004 100 year storm we would have about half the surcharge percentage.
- This shows the Markham 100 year design storm and the conservation authority 100 year floodline mapping storm – there is a big difference, and one is more conservative for flashy urban systems.
- What and where do we need to adapt for tomorrow’s expected extremes? … same as for “design standard adaptation” for yesterday’s and today’s extremes. I’ll show you the Markham example.
- Although local trends are downs we do look at future climate IDF to stress test sewer systems. Its easy pick the starting point, pick the future climate scenario and stress test any system that is designed below the future standard. We are doing this in Markham.
- Although local trends are downs we do look at future climate IDF to stress test sewer systems. Its easy pick the starting point, pick the future climate scenario and stress test any system that is designed below the future standard. We are doing this in Markham.
- But it is not that easy – there is no simple future scenario and they all diverge up and down even. But it doesn’t matter – back to the question of adaptation. And lets scale this chart to show the old standards.
- This shows todays standard and a range of possibilities. We have tested that new systems can handle a 20-30 % increase in IDF if we use inlet controls and modern standards. But some old systems were designed down here. @ year sewers and no overland flow path – it is a no brainer that we will achieve significant risk reduction by increasing the standards in those areas even to todays rain intensities – and the greatest marginal return on investment will be on in the most deficient areas. There will also be diminishing relative marginal returns above that. Most cities have decades of this basic design capacity adaptation to do to bring up old system to todays standards.