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

Gmilner@trca.on.ca

For more information, please visit:

http://climateontario.org | www.trca.on.ca