Transcript Slide 1

Livable Region Strategy Plan Review
towards 2031
Infrastructure Integrity and Climate Change:
Metro Vancouver Case Study
Brent Burton, M.A.Sc., P.Eng.
Utility Analysis and Environmental Management Division
Policy and Planning Department
Metro Vancouver
APEGGA Professional Development Sessions
Infrastructure Integrity – Climate Change Impacts and Adaptation
Shaw Conference Centre, Edmonton, Alberta
April 18, 2008
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Livable Region Strategy Plan Review
towards 2031
Outline
• Background on Metro Vancouver
• Existing role in water supply and
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wastewater
Adaptation and Metro Vancouver
Metro Vancouver sewerage case study
Next Steps
Livable Region Strategy Plan Review
towards 2031
Metro Vancouver
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Common name of several legal entities including Greater
Vancouver Water District and Greater Vancouver Sewerage and
Drainage District
Partnership of 21 municipalities and one electoral area
Board comprises elected officials from member municipalities
Services a population exceeding two million (projected 2.7
million by 2027) and a land area of approx 280,000 ha
Livable Region Strategy Plan Review
towards 2031
Role of Metro Vancouver
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Delivery of utility services most effectively and efficiently
provided on a regional basis
Protection and enhancement of quality of life in the region
Livable Region Strategy Plan Review
towards 2031
Role in water supply
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Supply water to most of region from three
mountain reservoirs
Reservoirs are typically spilling about 9 months a
year
High demand in summer (outdoor water use)
Largely supplied by gravity during winter
towards 2031
Livable Region Strategy Plan Review
Role in wastewater
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Maintain and operate major interceptor sewers
Maintain and operate 5 treatment plants
AAD (MLD) = 98
AAD (MLD) = 603
AAD (MLD) = 11
AAD (MLD) = 78
AAD (MLD) = 510
Livable Region Strategy Plan Review
Liquid waste planning
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Policies and commitments
identified in Liquid Waste
Management Plan
(approved by Province in
2002)
• Climate change not
specifically identified in
LWMP
Currently undergoing
regularly-scheduled 5-year
review and update
towards 2031
Livable Region Strategy Plan Review
towards 2031
Metro’s role and climate change
adaptation
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Mitigation activities (GHG reduction) already
well established by late 90s via air quality role,
but…
Awareness of need for adaptation still
developing
Adaptation issues first formally reviewed in an
overview in 2000:
• Adaptation Strategies for Utility Planning
(Environment Canada)
• Identifies climate projections and briefly outlines potential impacts
(rising sea levels, spring flooding, summer drought, etc.)
Livable Region Strategy Plan Review
towards 2031
Metro’s role and climate change adaptation
for wastewater infrastructure
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Focus on precipitation analysis for wastewater
systems in 2002
• Development of GVRD Precipitation Scenarios (KWL
Consulting)
• Comprehensive analysis of historical precipitation
and future projections,
• Identifies patterns of increased rainfall
• But likely yet “…no urgent need to upgrade the
capacity of combined sewers, storm sewers and
drainage systems.”
• But situation needs to be monitored and periodically
re-assessed…
Livable Region Strategy Plan Review
towards 2031
2004: Increasing recognition of need for
adaptation in engineering practice
Livable Region Strategy Plan Review
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2005: Drinking Water Management Plan
• A number of recent studies
used to identify climate
change impacts / adaptations
• Some impacts / adaptations
related to ensuring sufficient
water stored for summer
months and increased efforts
at DSM
• Climate change may move
forward the date when storage
increase required (i.e. dam
raising, lower intakes and
alpine lakes) by approximately
10 years.
Livable Region Strategy Plan Review
towards 2031
And then there was 2007…
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IPCC report released early in the year
GVRD Historical and Future Rainfall Analysis
Update (Pacific Climate Impacts Consortium)
• Generally affirms KWL conclusions
• Identifies more evidence of statistically-significant
trends of increased rainfall (especially short duration
storms in spring)
Political Board requests update on adaptation
activities
Livable Region Strategy Plan Review
towards 2031
Engineers Canada and vulnerability assessments
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Staff membership on Water Resources Expert
Working Group and Stormwater / Wastewater
Expert Working Group
Staff determined that wastewater vulnerability
assessment needed most urgently
At staff request, Board approves partnership
with Engineers Canada in study of wastewater
infrastructure vulnerability
Livable Region Strategy Plan Review
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Initiating vulnerability assessment
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Agreement developed between Metro Vancouver
and Engineers Canada
Working with Engineers Canada, staff issued
Request for Proposal focussing on Vancouver
Sewerage Area
KWL Consulting awarded contract
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Lead: Andrew Boyland, P.Eng.
Associated Engineering
• Treatment Sub-Consultant
• Dean Shiskowski, Ph.D, P.Eng.
towards 2031
Livable Region Strategy Plan Review
Local Geography of VSA
North Shore Mountains
Burrard Inlet
Iona Island WWTP
Strait of
Georgia
Fraser River
Livable Region Strategy Plan Review
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Quick Facts:
Vancouver Sewerage Area
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Service Population: 600,000
Service Area: 13,000 ha
Predominantly serviced by
combined sewers
• Combined sewer overflows during
wet weather
Approximately 40% serviced by
separated sanitary sewers
Wastewater drains to Iona Island
Wastewater Treatment Plant
As well as City of Vancouver, VSA
includes all of UBC and part of the
cities of Burnaby and Richmond
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Regional collection system
Livable Region Strategy Plan Review
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Climate Quick Facts:
Vancouver Sewerage Area
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Located in a west-coast marine climate zone
Regional climate highly influenced by El Nino Southern
Oscillation and Pacific Decadal Oscillation (additive or
mitigating)
Generally subject to west to east weather patterns
• Winter climate dominated by repeated cyclonic storms (long
duration precipitation of moderate intensity)
Rainfall
• Annual rainfall is typically about 1,800 mm
• One day maximum rainfall about 73.1 mm
• Typically highly variable through region due to geography
Temperatures
• January temperatures average about -0.6 to 5 deg C.
• August temperatures average about 11 to 23 deg C.
Livable Region Strategy Plan Review
Quick Facts on Liquid Waste
Management Plan
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Sewer separation is major
long-term strategy outlined
to address CSOs
• Commitment to eliminate
CSOs by 2050 with interim
rates of sewer separation
• Most regional sewers, once
fully separated, would be
transferred to City
ownership
Iona upgrade to secondary by
2020
Iona to maintain 17 m3/s
peak flow capacity
towards 2031
towards 2031
Livable Region Strategy Plan Review
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Infrastructure components considered
upstream of treatment plant
Wastewater Infrastructure and Collection
System
Combined Sewer Trunks
Pump Stations & Wet Wells
Force Mains
Siphons
Outfalls
Manholes
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Flow & Level Monitors
Grit Chambers
Flow Control Structures
Control Valves
Air Valves
Livable Region Strategy Plan Review
towards 2031
Iona Island Wastewater Treatment Plant
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Began operating in 1963
Primary treatment
• Current plan is to upgrade
to secondary by 2020
Discharges through a 7 km
deep sea outfall to Strait of
Georgia (90 m below sea
level)
2007 AAD = 603 MLD
towards 2031
Livable Region Strategy Plan Review
Infrastructure components considered at
treatment plant
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Process, hydraulic and supporting
infrastructure
Screening
Influent pumping
Grit removal
Primary clarification
Sludge thickening
Sludge digestion
Sludge lagoons
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Treatment liquid stream
Effluent disposal
On-site pipelines
Buildings, tankage and
housed process
equipment
Standby generators
Livable Region Strategy Plan Review
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Timelines and general climate factors
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Focus on 2020 and 2050 (i.e. no 2080 scenario)
Climate modelling by OURANOS suggested that
by 2020 and, to a greater extent by 2050, we can
expect:
• Increased rainfall, including more frequent and more
intense rainfall events
• Rises in the sea level
• Increases in storm surge, floods and extreme gusts
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towards 2031
Detail climate factors
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2050 Horizon
• *Intense Rain – (24 hr – 73mm) ➚ 17% increase
• *Annual Rain – (1881mm) ➚ 14% increase
• *Sea Level – 0.3 – 1.6m (2080 Horizon) increase
• *Storm Surge – N/A, expected increase
• Temperature – 1.4 – 2.8c increase
• Drought – no change (20 days)
• Wind – N/A, expected increase
Livable Region Strategy Plan Review
Climate factors
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Snowfall – decrease
Frost, Ice, Freeze Thaw – decrease
Other Effects:
Flooding – Fraser River - decrease (?)
Ground Subsidence – 2mm/yr
Data Gaps:
• Rainfall IDF curves, shorter durations
• Wind, Storm Surge
towards 2031
towards 2031
Livable Region Strategy Plan Review
Key Vulnerabilities
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Key Vulnerabilities
• Combined Sewer
Overflows (CSO)
• Intense rain, annual rain
• WWTP Flooding
• Combined effects of
storm surge, sea level
rise and subsidence
• Effluent Disposal –
outfall/jetty structure
• Storm surge, wind/wave
effects
Photo: Corporation of Delta
Livable Region Strategy Plan Review
Detail vulnerabilities
towards 2031
Livable Region Strategy Plan Review
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Policy Recommendations
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Important to use this information in:
• Review and update of the Liquid Waste
Management Plan (i.e. regional design standards /
commitments related to climate change,
reaffirming commitments to green infrastructure?)
• Next phase of treatment upgrading (i.e. designing
secondary treatment to accommodate sea level
rise and storm surge)
• Reaffirming timelines and commitments to sewer
separation
Livable Region Strategy Plan Review
towards 2031
Technical recommendations
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Further study suggested to determine increase
in sewer flows
Further study suggested to determine if
additional sewer separation effort required to
eliminate CSOs by 2050
Identify stand-by power requirements
Assess potential for WWTP flooding
Livable Region Strategy Plan Review
towards 2031
Cross-cutting issues (?) for other
communities
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Combined Sewers may have ‘built-in’ adaptive capacity.
• Designed to overflow in controlled manner
• Many built when sizing was empirical. (i.e. big enough for a
person to walk through)
• Mitigation of CSOs and reduction of risk consistent with sewer
separation and can be consistent with adaptation (if new
climate data considered)
Climate data uncertainty
• Regional models unable to account for local effects (wind
speed & direction, storm surge, extremely variable geography)
• Expense/practicality limited the model runs to two initial
conditions (same GHG scenario)
Livable Region Strategy Plan Review
towards 2031
Cross-cutting issues (?)
• Infrastructure vulnerability issues more cross-cutting than
climate change factors?
• i.e. climate change factors possibly only relevant to Vancouver
(mild coastal effects), but the “infrastructure deficit” is more
cross-cutting
• Process highlights ongoing management actions
• i.e. complete emergency response plan, review standby power
availability
• Design assumptions for very old infrastructure often not
readily available
• i.e. to determine basis of capacity
Livable Region Strategy Plan Review
towards 2031
Next steps for Metro Staff
• Report to Regional Engineers Advisory
Committee
• Consists of most senior engineer from each member
municipality
• Discuss and finalize technical recommendations
• Report to Waste Management Committee and
Board
• With recommendation for further actions and studies
for this and other aspects of our utilities
• Major policy decisions ($$$) need Board approval
Livable Region Strategy Plan Review
towards 2031
Questions?
Metro Vancouver Sewerage Area Case Study