Infrastructure Integrity and Climate Change: Metro Vancouver Case Study

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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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Outline

• Background on Metro Vancouver
• Existing role in water supply and wastewater
• Adaptation and Metro Vancouver
• Metro Vancouver sewerage case study
• Next Steps

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Metro Vancouver

• 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

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Role of Metro Vancouver

• Delivery of utility services most effectively and
  efficiently provided on a regional basis
• Protection and enhancement of quality of life in
  the region

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Role in water supply

• 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

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Role in wastewater

• Maintain and operate major interceptor sewers
• Maintain and operate 5 treatment plants

AAD (MLD) 98
AAD (MLD) 603
AAD (MLD) 11
AAD (MLD) 510
AAD (MLD) 78
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Liquid waste planning

• 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

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Metros role and climate change adaptation

• 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.)

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Metros role and climate change adaptation for
wastewater infrastructure

• 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

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2004 Increasing recognition of need for
adaptation in engineering practice
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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.

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And then there was 2007

• 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-signific
  ant trends of increased rainfall (especially
  short duration storms in spring)
• Political Board requests update on adaptation
  activities

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Engineers Canada and vulnerability assessments

• 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

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Initiating vulnerability assessment

• 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

• Lead Andrew Boyland, P.Eng.
• Associated Engineering
• Treatment Sub-Consultant
• Dean Shiskowski, Ph.D, P.Eng.

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Local Geography of VSA

• North Shore Mountains

Burrard Inlet

• Iona Island WWTP

• Fraser River

• Strait of
• Georgia

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Quick FactsVancouver Sewerage Area

• 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
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Climate Quick FactsVancouver Sewerage Area

• 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.

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Quick Facts on Liquid Waste Management Plan

• 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

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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

• Flow Level Monitors
• Grit Chambers
• Flow Control Structures
• Control Valves
• Air Valves

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Iona Island Wastewater Treatment Plant

• 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

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Infrastructure components considered at treatment
plant

• Process, hydraulic and supporting infrastructure
• Screening
• Influent pumping
• Grit removal
• Primary clarification
• Sludge thickening
• Sludge digestion
• Sludge lagoons

• Treatment liquid stream
• Effluent disposal
• On-site pipelines
• Buildings, tankage and housed process equipment
• Standby generators

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Timelines and general climate factors

• 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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Detail climate factors

• 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

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Climate factors

• 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

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Key Vulnerabilities

• 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
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Detail vulnerabilities
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Policy Recommendations

• 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

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Technical recommendations

• 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

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Cross-cutting issues (?) for other communities

• 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)

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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

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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

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Questions?

• Metro Vancouver Sewerage Area Case Study