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Updating Water
Infrastructure Design for
Climate Change Adaptation
Glenn Milner
AWRA Summer Specialty Conference
June 28, 2017
Outline
• What is a Conservation Authority?
• Engineering Challenge in Policy and Existing Tools
• Project: Updating Water Infrastructure Design
incorporating Climate Change
– Phase 1: Deriving Future IDF Curves using Climate
Projections
– Phase 2: Technical Guidance on new Approaches to
Water Infrastructure Design for Climate Adaptation
What is a Conservation Authority? (CA)
• Created in 1946 under Ontario’s ‘Conservation Authorities Act’
• Mandate:
– Ensure the conservation, restoration and responsible management of
Ontario’s water, land and natural habitats through programs balancing
human, environmental and economic needs.
• A few of Toronto and Region Conservation Authority’s Programs:
– Floodplain management and Flood Warning
– Development Review and Regulation (in CA jurisdiction)
– Erosion Control
– Watershed Planning and Research
– Monitoring of Groundwater, Surface water and Ecological features
– Stormwater management
– Climate Change
Then, in 1954…
• Hurricane Hazel made landfall in Toronto, taking 81 lives and
causing $1.28 billion in damage (in 2017, Canadian dollars)
• Since then, increased authority was over land acquisition and
regulation was given to the Conservation Authorities
TRCA’s Climate Change Hub
Ontario Climate Consortium (OCC) Services…
1. Vulnerability and Risk Assessments
• Natural Systems
• Agricultural System
• Stormwater Infrastructure
• Community Services, etc.
2. Climate Adaptation Planning with Municipalities across the
Province
3. Climate Information and Scenario Analysis in support of
Climate Adaptation
4. Stakeholder Engagement: Workshops, Think-tanks, Research
Symposia
ENGINEERING CHALLENGE IN
ONTARIO
Climate Policy Required Updates…
• Climate change will increase
intense rainfall
• Practitioners must
acknowledge this in design
• Updated Ontario Adaptation
Plan to be released end of
2017
…And Engineers Responded
• University of Western Ontario
– IDF CC Tool: http://www.idf-cc-uwo.ca/
• Ontario’s Ministry of Transportation
– MTO Tool:
http://www.mto.gov.on.ca/IDF_Curves/
• But, uncertainty of climate projections were not
originally reflected or explained adequately
Municipal Infrastructure Context
(Stormwater)
• Stormwater Infrastructure owned and managed by municipalities
includes: pipes, catchbasins, culverts, stormwater ponds, etc.
• Barriers to ‘mainstreaming climate change’:
– Silos across municipal service departments
– Lack of continuous data records or digital information
– Legacy funding leading to ‘bursts’ of information about municipal
infrastructure system in hot spots, but not everywhere (inspections, etc.)
NORTHWEST TORONTO TORONTO TRANSIT CORRIDOR
Updating Water Infrastructure Design
to incorporate Climate Change
Project Overview
• Objective: To provide technical guidance to municipal
engineers on how to integrate climate change into
stormwater infrastructure design.
• Phase 1: Investigated multiple methods for deriving
future IDF curves that incorporate climate projections
– Case Study in Toronto and Essex Regions of Ontario
• Phase 2: Produce technical guidance on incorporating
climate change into SW infrastructure design
Phase 1 Objectives & Partners
• To understand the implications of
using different methods for
incorporating climate change into
IDF curves;
• To apply this approach in Essex
and Toronto regions of Ontario.
Future IDF Curve Methodology
5 Climate Models
1-2 Emissions Scenarios
2 Downscaling
Methods
16 Permutations
15 Climate Stations
Annual maximum rainfall for different
durations (1hr, 2hr, 3hr, 6hr, 12hr, 24hr)
Climate Models Used…
Model Rationale Spatial
Resolution Temporal
Resolution
Scenarios
Historical A2 RCP
4.5 RCP
8.5
RCMs
CRCM3
(CGCM3) Canadian
context 50 km 3-hours ✔ ✔
HRM3
(HadCM3) Popular RCM 50 km 3-hours ✔ ✔
CanRCM4
(CanESM2) Canadian
context 40 km 1-hours ✔ ✔ ✔
GCMs
HadGEM2-ES Popular GCM Approx. 120
x 139 km 3-hours ✔ ✔ ✔
MIRCO-ESM
"Best"
performing
GCM in
Sheffield et al.
(2013)
Approx. 150
km 3-hours ✔ ✔ ✔
Downscaling Delta and Bias Correcting Methods
http://climateconnections.ca/our-work
Report Available Online at:
37 mm/h
110 mm/h
Toronto
Pearson Int’l
Airport Station
2090s
100yr Return
Period Storm
10th-90th
Percentile
Key Messages on Deriving Future IDF
Curves
• Climate models aren’t great with resolving or projecting
convective extreme rainfall events
• Climate model and emissions scenario selection has a
profound effect on calculated IDF curves
• IDF statistics vary widely between stations in the same
area: selection of climate station also has a profound
effect on calculated IDF
• Range of uncertainty for short durations and large return
periods at a single station can exceed 100%
Phase 2 – Current Initiatives
• Objective: To Provide technical guidance for stormwater
infrastructure owners on how to incorporate climate change into
infrastructure design
– Working Group established among municipal partners
– Literature Review and Mapping adaptation pathways to identify broad
patterns, trends and options for asset design & management (ongoing)
– Stakeholder workshop with experts to (late summer)
– Produce Technical Guidelines (early fall)
• Goal: Shift focus away from the derivation of a single, definitive set
of future IDF curves to a probability based approach or one focused
on risk tolerance
Different adaptation activities correspond to different expenditure pathways. Type I is incurred in the immediate future (e.g. emergency services). Type II relates to activities which typically occur on an annual basis. Type III is what economists hope for - wait until you absolutely must change.
Thank You!
Glenn Milner
For more information, please visit:
http://climateontario.org | www.trca.on.ca