Building Municipal Resilience to Future Storms. Heather Auld; Risk Sciences Intl

Transcription

1 Building Municipal Resilience to Future Storms Heather Auld; Risk Sciences Intl

2 4 Cornerstones of Infrastructure Resilience to Climate Change Projections/ From Resilience Engineering in Practice: A Guidebook Update knowledge; Thresholds, gaps Monitor; Watch Critical thresholds & Emergency plans & response; Surprises! Forensics; Fix it!; Codes, practices

3 4 Cornerstones of Infrastructure Resilience to Climate Change Projections/ From Resilience Engineering in Practice: A Guidebook Update knowledge; Thresholds, gaps Monitor; Watch Critical thresholds

4 Resilience: Knowing what to expect & Looking for it (Monitoring)

5 Mean Annual Temperature Trends: Ongoing Warming Our Past Present Near Mid-Century Future Future 2020s Average Average 2050s Annual Average Annual Temperature Annual Temperature (AR5-RCP8.5) (AR5-RCP8.5)

6 Mean Annual Precipitation Trends: Becoming Wetter Our Past Present Near Mid-Century Future Future 2020s Average 2050s Average Annual Precipitation Annual Precipitation (AR5-RCP8.5) (AR5-RCP8.5) (mm)

7 Climate Change is here to stay

8 Uncertainties in climate change model outputs vary Most Confident More CERTAINTY Least / Less Confident Less CERTAINTY Longer growing season Warmer winters More heat waves More winter precipitation More intense rainfall More severe ice, snow storms Increase in wind extremes

9 Climate Information & Infrastructure Performance Structures Roads, Bridges Electrical power distribution structures Buildings (including airports) Risk of failure Ice & Snow Loads Road safety, Flooding risks, Operations. Deterioration FAILURE RISKS FAILURE RISKS Extreme Rain (Intensity, Duration, Freq) FAILURE RISKS drainage & erosion Underground, Vaults, Towers if widespread flooding Flooding; failure risk Extreme Winds Failure risks for signs, some bridge components FAILURE RISKS FAILURES Risks to infrastructure services

10 Each generation of climate models has projected increased precipitation for southern Ontario IPCC Model Projections over time Toronto Annual Precipitation Change (%) for the 2050s Trends are upwards Amounts TBD (from baseline) (all models, all experiments) 1995 (n=11) 2001 (n=14) 2007 (n=171) 2013 (n=208) SAR TAR AR4 AR5 + 7% ~ 0%

11 But, Largest Increases likely for Extreme Rainfall Also Largest Uncertainties among CC Models Largest Increases likely for extreme rainfall More and more of our total annual precipitation will come from extreme events (e.g. 7% currently to ~18% by 2080s) High +1 StDev Ensemble mean Low -1 StDev Increases on average 35-40% by 2050s (29mm avg) But, one model decreases by ~60mm; few others increase > 60mm

12 Winter Snow Storms, Rain on Snow, Snowmelt Shorter winters More days with nil snow on ground More winter rain And, potential for bigger mid-winter snow storm systems and increased lake effect snowfalls Polar vortex winters?? Owen Sound, Jan, 2014

13 Trends in Annual Snowfall Anomalies from Lake Michigan-Huron Lake-Effect Snowbelt Huntsville, April, 2013 Bruce Co, Feb,

14 Changes in Weathering day-to-day weather Increases in day-to-day weathering also impact Resilience

15 4 Cornerstones of Infrastructure Resilience to Climate Change Projections/ From Resilience Engineering in Practice: A Guidebook Emergency plans & response; Surprises! Forensics; Fix it!; Codes, practices

16 Resilience: Planning Responses and Learning from Failures, Surprises

17 Adaptation Choices for Climate & Weather Resilience Do nothing Strengthen existing & new (e.g. safety factors; return periods; retrofits) Current Climate Monitor; Improve science New approaches (e.g. deep water cool) Manage extremes (e.g. disaster planning; PIEVC risk assessment) DESIGN (new structures?) With Climate Change OPERATIONS (existing/new) Add Resilience; Stage; Flexible Include future climate (PIEVC) Improve (Repair & retrofit; maintenance) Financial (insurance; Mun. reserves)

18 Options to Increase Climate Resilience Prioritization of hazards/risks and disaster risk reduction planning Hard engineering options: Better and new building and engineering codes, standards, practices Larger safety factors and more redundancy in infrastructure design Priority retrofits of the most vulnerable at risk structures Phased adaptation actions berms built for additional height/safety Soft engineering options: Maintain ecosystem services Healthy (and changing) ecosystems Merging of soft (green) and hard infrastructure solutions

19 NO REGRETS Example: Implement Current Life-saving Tornado Measures - NBCC & CSA Based on forensic analyses from 1985 Barrie-Grand Valley tornadoes

20 Small changes above critical thresholds matter actions before thresholds reached Number of Claims/day Southern Ontario Municipality Insurance Claims from Severe Wind Events (housing & buildings) Threshold gust Peak wind gusts

21 Flexible adaptation options working with Infrastructure Asset Management Timeframes Structures Expected Lifecycle Houses/Buildings Sewer Dams/Water Supply Bridges Retrofit/alterations yrs Demolition yrs Major upgrade 50 yr Refurbishment yrs Reconstruction 50 yrs Maintenance annually Resurface concrete yrs Reconstruction yrs Improved Asset management

22 Adaptation Example: Extreme Rainfall Municipalities, Conservation Authorities: More rainfall data, better rainfall design values Stormwater infrastructure upgrades, margins for future Low impact development (LID): Rain gardens, bioswales, impervious pavement Roof collection Back-water valves & sump pumps; Downspout disconnects Credits for risk reduction actions?: Home owner water credit for increasing infiltration, rain water collection Tax credit for planting approved trees

23 Low Regrets Green Engineering & Best Management Practices: Ecosystem Services to the Rescue

24 Stormwater Management: Low Impact Options Green Infrastructure, Low Impact Development Constructed systems that mimic natural processes to infiltrate, evapotranspirate, or reuse stormwater or runoff New development, redevelopment, retrofits to existing urban areas Instead of/ in addition to more traditional stormwater control

25 Elm Drive, South Mississauga: Permeable Planters, Bioretention planters (rain garden) Stormwater runs through permeable pavers & bioretention planters before discharging to existing storm sewers BEFORE Various aggregate & Salt tolerant native plants

26 Elm Drive, Mississauga Results of LID Retrofits 75% of Mississauga without flood control (pre-swm) 95% of rain events since 2011 did not produce ANY runoff/stored onsite; Provides groundwater recharge No outflows for snowmelt or rainfall events 25mm July 8, 2013 event > 100 year storm (104mm rainfall in 5 hours) LID reduced July, 2013 peak loads ~ 60%, volume by 30%, held back runoff for minutes No damage to system from July extreme rainfall Overall, contaminants reduced by > 94%; 99% suspended solids removed (Courtesy of Credit Valley CA)

27 Future Extreme Rainfall Design Values (IDF) Climate change models not so good at ground-truthing extremes Ontario Inter-comparison study of future extreme rainfall curves (IDF) High level of uncertainty among future IDF approaches All approaches are experimental - LARGE differences, uncertainties DUE DILIGENCE low regrets best management practices for today Add margins for climate change regionally Uncertainties lower for < 25 year return period, > 1 hour duration Multi-models, probabalistic future IDFs, best performing models? 27

28 Increasing Climate Resilience through new and updated Codes and Standards Codes & standards level the playing field requiring resilience Codes & Standards can change given evidence - need, trends, impacts Often evidence from forensic analyses learn from vulnerabilities BUT, unfortunately Many outdated climatic values in current Codes and Standards New Opportunities National Building Code Option to include CC adaptation 4 new Northern CSA Adaptation standards + Rainfall IDF standard Engineers Canada vulnerability assessments No regrets requirement - update the decades old climate values London, Dec, 2010

29 4 Cornerstones of Infrastructure Resilience to Climate Change Projections/ From Resilience Engineering in Practice: A Guidebook Update knowledge; Thresholds, gaps Monitor; Watch Critical thresholds & Emergency plans & response; Surprises! Forensics; Fix it!; Codes, practices

30 Contact: HEATHER AULD Risk Sciences International