Download Climate Risk and Resilience Planning for Wastewater Infrastructure

Climate Risk and Resilience Planning for
Wastewater Infrastructure
Laurens van der Tak, PE, D.WRE
VWEA Education Seminar –
Managing Risk through Process and Organizational Innovation
May 12, 2016
Presentation Outline
Climate Change Threats
Adaptation Strategy Framework
Climate Change Adaptation Case Studies
Miami-Dade Water and Sewer Department
Boston Water and Sewer Commission
2
Climate Change Threats:
Rainfall, Extreme Storms and Sea Level Rise - Impacts Vary Based
on System Function and Source (Drainage, Riverine, and Coastal)
Precipitation
Sea level rise
Storm surge
Precipitation timing,
2- to 10-year
storms
Stormwater/Drainage
Management
3
Localized flooding
Increased CSOs
100-year
storms
Riverine Floodplain
Management
Regional flooding
Tidal flooding
Tropical
storms
Climate Change will make storms we design for more intense, and
increase the frequency (ie risk) of exceeding design criteria for
flood protection.
Precipitation
Precipitation timing,
10-year storm depth
will increase by
about 1 inch
A 100-yr becomes 50yr recurrence
4
Adaptation Framework:
When dealing with future uncertainty an adaptive planning
process provides needed flexibility.
5
Steps to identify strategies to increase resilience to sea level rise:
11
2
3
Frame the
Identification
of
ProblemVulnerabilities
Frame the
Problem
“What are the
overarching
questions to
answer and sea
level rise
scenarios to plan
for, with the
goal of
increasing
resilience to sea
level rise?”
and Risk
“What are the overarching
Identify and
assess
questions to answer
and
infrastructure
that may be
sea level rise scenarios
impacted byto
sea
level rise.
plan for, with the goal of
increasing resilience to
sea level rise?”
6
4
Develop a list
of potential
adaptation
strategies
Determine the
range of
strategies that
will provide the
best adaptation
to changing
future
conditions based
on identified
vulnerabilities.
Link
adaptation
strategies to
current
process
Review
adaptation
strategies to
identify those
that only require
an adjustment
or modification
to current
policies or
programs.
5
6
Implement
Adaptation
Strategies
Identify priority
strategies for
implementation:
those strategies
that are best
aligned with the
values, goals
and objectives
of the
implementing
organization .
Continually
Monitor and
Re-assess
Monitor sea
level rise, revisit
assessments and
re-assess
priority
strategies to
continually
inform future
actions to adapt
to changes in
sea level.
A problem well-defined, is a problem
half solved. ~Charles Kettering
• Are facilities near tidal waters, subject to sea
level rise and storm surge?
1
Frame the
Problem
“What are the overarching
questions to answer and
sea level rise scenarios to
plan for, with the goal of
increasing resilience to
sea level rise?”
• Are my operations at risk of riverine flooding or
greater I/I from sea level rise and higher rainfall?
• Are my operations at risk from power outages?
• What is the planning horizon for evaluating
climate change:
– Service life of assets
– CIP planning cycle, based on growth, land use change,
finances
• Select climate scenarios based on your risk
tolerance:
– Consider low, medium and/or high future scenarios
7
Scenario analysis…accounting for future uncertainty
160
140
Sea Level Rise Scenarios
Precautionary
Trend
100-cm
(3.3-ft)
Sea level above 2010, cm
120
100
80
60
Historic Trend
40-cm
(1.3-ft)
40
20
0
2010
2020
2030
2040
2050
2060
2070
2080
2090
2100
Year
8
Extrapolated Historic Trend Line
Curve 1 (2100 End Point = 70 cm)
Curve 2 (2100 End Point = 100 cm)
Curve 3 (2100 End Point = 140 cm)
Curves adapted from the NC Coastal Resources Commission Science Panel on Coastal Hazards 2010
NC Sea Level Rise Assessment Report (March 2010)
Steps to identify strategies to increase resilience to sea level rise:
2
1
Frame the
Problem
“What are the
overarching
questions to
answer and sea
level rise
scenarios to plan
for, with the
goal of
increasing
resilience to sea
level rise?”
9
4
Develop a list
of potential
adaptation
strategies
Identification of
Vulnerabilities
and Risk
Determine the
range of
strategies that
will provide the
best adaptation
to changing
future
conditions based
on identified
vulnerabilities.
Identify and assess
infrastructure that may
be impacted by sea level
rise.
Link
adaptation
strategies to
current
process
Review
adaptation
strategies to
identify those
that only require
an adjustment
or modification
to current
policies or
programs.
5
6
Implement
Adaptation
Strategies
Identify priority
strategies for
implementation:
those strategies
that are best
aligned with the
values, goals
and objectives
of the
implementing
organization .
Continually
Monitor and
Re-assess
Monitor sea
level rise, revisit
assessments and
re-assess
priority
strategies to
continually
inform future
actions to adapt
to changes in
sea level.
Asset Inventory and Risk Evaluations
provide a strong foundation for CC
Vulnerability Assessments
• Identify major asset types of interest, e.g.:
2
– Wastewater treatment plants
Identification of
Vulnerabilities
and Risk
Identify and assess
infrastructure that may
be impacted by sea level
rise.
– Wastewater pump stations
– Gravity sewers and manholes
– Force mains
• Define the critical elevations for these assets
• Identify vulnerable assets.
• Define probability of inundation events and
likelihood of damage.
• Determine consequence of failure.
• Determine risk level: high, medium, and low risk
groupings.
10
Climate risk builds on asset management
information to understand critical assets
Driven by Asset Management
program data
Asset Characterization
Susceptible Assets
Vulnerable Elevations
Damage Thresholds
Consequence of Failure
Hazard Characterization
Sea Level Rise Scenarios
Extreme Events
11
Vulnerability:
Risk = P(Event)*
[P(Damage)*P(Consequence)]
Adaptation
Options
Climate risk builds on asset management
information to understand critical assets
Asset Characterization
Susceptible Assets
Vulnerable Elevations
Damage Thresholds
Consequence of Failure
Hazard Characterization
Sea Level Rise Scenarios
Extreme Events
12
Vulnerability:
Risk = P(Event)*
[P(Damage)*P(Consequence)]
Adaptation
Options
Climate Vulnerability Assessment Relies on Asset
Inventory and Risk Assessment
WWTP Electrical Building At Risk from 100-yr
storm surge and 100 cm SLR
13
Manhole Risk Identification
Climate risk builds on asset management
information to understand critical assets
SLR Impacts on
Wilmington NC
Asset Characterization
Susceptible Assets
Vulnerable Elevations
Damage Thresholds
Consequence of Failure
Hazard Characterization
Sea Level Rise Scenarios
Extreme Events
Vulnerability:
Risk = P(Event)*
[P(Damage)*P(Consequence)]
• SLR Hazards = SLR scenario x event
• SLR scenarios
40 cm rise – historic trends scenario
100 cm rise – precautionary scenario
• Events
14
Mean higher high water (MHHW)
10-year flood elevation
100-year flood elevation
Adaptation
Options
Adaptation Strategies for Improving Flood Resilience

Adaptation Strategies for Stormwater
Management and Flood Protection Systems

Grey Solutions:
•
•
•
•
•
•
•
•
•

15
DC Water Blue Plains Flood Wall
Source: Umair Irfan, eenews.net
Green Solutions:
•
•
•
•

Raising electrical and mechanical equipment
Sealing wall penetrations
Water tight doors
Adding tide gates to outfalls
Backup generators
Barriers or local surge walls
Adding capacity to the drainage network
Moving flows from one part of the system to another
Emergency response planning
Green infrastructure
Coastal wetlands
Renewable energy and Co-generation
Zoning and Land Use Planning
Phasing adaptations to account for uncertainty in
projections and risk tolerance
Water Street GI, Onondaga NY
Climate Change Case Studies
• NACWA: Confronting Climate Change Report to Congress
• City of Wilmington, NC
• NYCDEP – Wastewater Resiliency Plan
• Boston Water and Sewer Commission
• North Carolina Sea Level Rise Risk Management
• USEPA Climate Adaptation Strategies Guide
• City of Alexandria, VA
• Fairfax VA, Master Plan
• LA Bureau of Sanitation
• California Bay-Delta
• Colorado River Basin Study
• Berwick, ME
• Miami-Dade Water and Sewer Department
16
Miami-Dade Water and Sewer Department
17
MIAMI-DADE COUNTY WATER AND SEWER DEPARTMENT
Preliminary Facility Hardening Plan
Ocean Outfall Legislation Program
OOL Compliance Projects
19
Climate Resilience/Facility
Hardening- Objectives and
General Approach
• Assess projected climate change for key climate variables (sea level rise,
precipitation, wind, inundation due to surge)
• Define critical wastewater assets and risk due to climate change
• Define design criteria to minimize risk
• Develop facility hardening plans and design guidelines for WASD design teams
20
Findings/Recommendations:
•Climate Projections
•Facility Hardening
Design Guidelines
21
Precipitation IDF Projections
Impacts: Peak Flows and Flooding
WASD Pump Station Peak Flows Are
Based on 2-yr Storm:
• Historically: 4.5” (SFWMD, 2001)
• Updated: 4.9” (2014)
• Projected: 5.4” to 6” (2040 to 2100)
20
Precipitation (Inches)
18
16
14
12
10
Updated Historical
NOAA Atlas 14
2040 RCP 6.0 50%
2040 RCP 8.5 50%
2075 RCP 6.0 50%
2075 RCP 8.5 50%
2100 RCP 6.0 50%
2100 RCP 8.5 50%
8
6
18.74
17.42
16.83
16.26
15.84
15.49
14.51
14.48
9.60
8.829.189.00
8.268.038.578.68
4.694.894.774.804.844.934.885.04
4
2
0
2
10
Return Period (Years)
22
Source: CH2M / CLIMsystems, January 2015
100
2-year 24-hour Precipitation Projections
(Design Criteria for Peak Sewer Flows):
Implications for PS 187
RCP, % nonexceedance
2-Year 24hr Rainfall
(inches)
% Change
in Rainfall
Peak
Flow
Rate
(mgd)
“Current”
4.5
0%
151
0%
2040
RCP6.0/8.5, 50%
4.8
7%
155
3%
2040
RCP8.5, 90%
5.42
20%
167
11%
2075
RCP6.0, 90%
5.58
24%
171
13%
2075
RCP8.5, 90%
6.05
34%
180
19%
Horizon
%
Change
in flow
5.42 inch, 2040 projection selected based on
service life of PS
23
23
Precipitation for 2075: Flooding Impacts,
Particularly Coupled with Coastal Storm Surge
100-yr 24hr storm
projected to
increase from
14.5” to
17.4” – 20”
24
Stressor: Sea Level Rise
Impacts: Coastal Flooding and Increased I/I
(due higher GW)
Source: SE FL Climate Compact, DRAFT April 2015
25
Surge Modeling: Modeled Result
Comparison of Peak
Surge Elevation
(mNGVD)
26
Surge Modeling: Modeled Result
Distribution of
boundary Peak
Surge
Elevations:
100yr condition
Red: 100yr
+ 1.23m SLR
0
Transect Location
Blue:
Peak Surge Elevation (mNGVD)
1O1
2O2
3O3
4O4
5O5
6O6
7O7
8O8
9O9
10
10O
11
11O
12
12O
13
13O
14
14O
15
15O
16
16O
17
17O
18
18O
19
19O
20
20O
21
21O
22
26O
23
29O
1
2
3
4
5
6
NDWWTP
CDWWTP
CDWWTP
SDWWTP
Ocean
Bay
27
Projected Stillwater Elevations:
Surge+2075 SLR+2075 Extreme Rainfall
100-yr
28
100-yr + SLR
Findings/Recommendations:
•Climate Projections
•Facility Hardening
Design Guidelines
29
Factors in Setting Risk-based Design Criteria will be used
to evaluate cost/benefit of facility hardening
• Planning Horizon to establish the service life:
– 2075 for Critical Long-Term Facilities (e.g. WWTPs)
– 2040 selected for pump station flows (e.g. PS-1)
• Criticality, based on wastewater or pumping facility function, such as:
– Maintenance of facility hydraulics
– Maintenance of equivalent primary treatment, liquid train
– Maintenance of secondary treatment, liquid train
– Maintenance of solids treatment
– Ancillary facilities, such as administration and laboratory buildings
30
30
Factors in Setting Risk-based Design Criteria will be
used to evaluate cost/benefit of facility hardening
• Level of protection:
– NOAA (High) SLR curve
– USACE (High) SLR curve
• Level of Freeboard:
– 2 ft for WWTP vs Pump Stations in Coastal Flood Zones, ie. FEMA Zone V
(ASCE Standard 24-05/2010 FBC Category IV)
– 1 ft for WWTP vs Pump Stations in Inland Flood Zones, ie. FEMA Zones A, AE
(ASCE Standard 24-05/2010 FBC Category III)
• Level of Safety Factor:
– 0 ft for low risk facilities, or
– 1 ft as set by WASD at CDWWTP
31
31
Facility Hardening Costs were Developed for Critical
Facilities above Design Flood Elevation
32
Adaptation Strategies / Protective Measures
 Identified site-specific
protective measures to
minimize prolonged service
interruption and flood risk,
while balancing feasibility,
resiliency, and cost.
 Establish robust design
guidelines for future
wastewater infrastructure
upgrades/designs that assist in
mitigating flood risk.
Elevate Equipment
on pads or platforms, to
a higher floor, to the
roof, or to a new
elevated building.
Flood-Proof Equipment
by replacing pumps with
submersible pumps and
installing watertight
boxes around electrical
equipment.
Install Static Barrier
across critical flood
pathways or around
critical areas.
Seal Building
with water-tight doors
and windows, elevating
vents and secondary
entrances for access
during a flood event.
Sandbag Temporarily
around doorways, vents,
and windows before a
surge event.
33
Install Backup Power
via generators nearby or
a plug for a portable
generator.
Does not protect
equipment but
facilitates rapid
service recovery.
Source: NYCDEP
Facility Hardening Costs - WWTPs
Scenario 1 (Design Elevation 16.0 ft)
CD
OOL
(Existing
Total
Scenario 2 (2075 SLR + FB + SF)
CD
$ 4,576,200
$
4,576,200 $ 39,947,600
CDWWTP
5,513,000 $ 16,053,000 $
SDWWTP
$ 1,533,000 $ 3,980,000 $
NDWWTP
$ 9,213,000
$
9,213,000 $ 14,578,000
Note:
$
19,302,200
OOL Facility hardening was only estimated for retrofitting existing facilities.
New OOL facilities would be hardened to same design criteria.
34
OOL (Existing
Facilities)
$
7,650,000 $
$
$
Total
39,947,600
23,703,000
14,578,000
78,228,600
Facility Hardening Design Guidelines
for Existing and New WWTP Assets
WWTP Summary of Design Criteria for Hardening against Flooding from Surge, Sea
Level Rise and Extreme Storm Events.
Existing WWTP Facility Assets
New WWTP Facility Assets
ft
NGVD29
Basis
ft
NGVD29
Basis
CDWWTP
16.0
FEMA BFE + 3ft SLR from SEFLCC(2011) +FB
+SF
20.3
2075 Surge+1.23m(48")SLR + FB
+SF+21”(100-yr, 72-hr rainfall)
SDWWTP
16.0
FEMA BFE + 3ft SLR from SEFLCC(2011) +FB
+SF
19.0
2075 Surge+1.23m(48")SLR + FB
+SF+21”(100-yr, 72-hr rainfall)
NDWWTP
16.0
Same as CDWWTP and SDWWTP
17.1
2075 Surge+1.23m(48")SLR + FB
+SF+21”(100-yr, 72-hr rainfall)
FB= Freeboard = 2.0 ft per ASCE Standard 24-05/2010 FBC Category IV
SF= Safety Factor = 1.0 ft per 2014 MWH study at CDWWTP
SLR = 1.23m = 48" per NOAA High projection for 2075 (USACE High projection is 0.93m)
35
Boston Water and Sewer Commission
36
Climate Change Risks
• Increased Rainfall
• Increased river flows and flooding
– Charles River, Neponset River and Mystic River may
flood areas of the City during storms
• Sea Level Rise and Storm Surge
37
Forecasted 10-year, 24-hour Design Storm
Volumes and Peak Hourly Intensities
A recalculation of historical rainfall through 2012
indicated that their 4.8-inch design storm has
increased to 5.2 inches
Total Storm Volume
(inches)
Peak Hourly Intensity
(inches per hour)
Scenario
2035
2060
2100
2035
2060
2100
Medium (B2)
5.55
5.76
6.08
1.76
1.83
1.93
Precautionary
(A1FI)
5.60
6.03
6.65
1.78
1.91
2.11
BWSC’s current design standard is 4.8 inches
38
Climate change is increasing the size and intensity of this
design storm and it could be 6.65 inches by 2100.
Copyright © 2014 Boston Water and Sewer Commission 980 Harrison Ave. Boston, MA 02119 617-989-7000
Sea Level Rise Projections
Storm Surge Heights held Constant with Today
Source: Vermeer & Rahmstorf, 2009
Medium SLR Projections through 2100
Return Period
(years)
Boston (mm)
Boston (m)
Boston (ft)
2
868
0.87
2.85
5
1,067
1.07
3.50
10
1,194
1.19
3.92
20
1,311
1.31
4.30
50
1,457
1.46
4.78
100
1,562
1.56
5.12
200
1,664
1.66
5.46
500
1,793
1.79
5.88
1,000
1,887
1.89
6.19
Precautionary SLR Projections through 2100
Component
2035
2060
2100
Component
2035
2060
2100
Global (feet)
0.79
1.54
3.51
Global (feet)
1.21
2.20
6.20
Subsidence (feet)
0.08
0.16
0.30
Subsidence (feet)
0.08
0.16
0.30
0
0
0
Regional (feet)
0.23
0.39
0.66
0.87
1.70
3.81
Total (feet)
1.52
2.75
7.16
Regional (feet)
Total (feet)
39
Copyright © 2014 Boston Water and Sewer Commission 980 Harrison Ave. Boston, MA 02119 617-989-7000
Evaluated Flooding Risks to Sewer Systems
• Models of the Storm Drain
and Sewer Systems
(SWMM) to Calculate
Flows Now and in The
Future
• 2-dimensional computer
models (CH2M’s Flood
Modeler-FAST) to map
surface flooding due to
drainage and storm surge
40
Copyright © 2014 Boston Water and Sewer Commission 980 Harrison Ave. Boston, MA 02119 617-989-7000
Flood Modeler Simulation of
Hurricane Sandy
Source: Douglas, et. al. 2013.
41
Copyright © 2014 Boston Water and Sewer Commission 980 Harrison Ave. Boston, MA 02119 617-989-7000
Risks Of Flooding With Sea Level Rise And Storm Surge –
Year 2060 with 10-year/24-hour Rainfall
Year 2060 Rain
Year 2060 Rain
Sea Level Rise, No Storm Surge
Sea Level Rise, With Storm Surge
42
Copyright © 2014 Boston Water and Sewer Commission 980 Harrison Ave. Boston, MA 02119 617-989-7000
43
BWSC
PUMP STATION (FACILITY ID)
MWRA
Copyright © 2014 Boston Water and Sewer Commission 980 Harrison Ave. Boston, MA 02119 617-989-7000
Port Norfolk
(11LPS316)
Austin Street
(27JPS1)
Symphony Hall
(21IPS1)
MWRA DeLauri
(MWRA002)
Union Park (21KPS2)
Summer Street
(22MPS5)
Public Alley 701
(21JPS526)
Trilling Way
(22MPS2)
Caruso
(29NPS4)
MWRA Prison Point
(MWRA003)
Commonwealth Ave
(22IPS1)
Sullivan Square
(29JPS1)
MWRA Cottage Farm
(MWRA001)
TOTAL RISK (0-100)
Pump Station Risk Scoring for Precautionary
2100 Scenario with Storm Surge
Pump Station Total Risk Score for P2100 with Storm Surge (23.50 feet)
100
90
80
70
60
50
40
30
20
10
0
Future Condition Without and With Flood Walls
Precautionary 2060
Precautionary 2060 With Flood
Walls
Flooding due to SLR and storm surge only, no rainfall in these calculations
44
Copyright © 2014 Boston Water and Sewer Commission 980 Harrison Ave. Boston, MA 02119 617-989-7000
Drainage Would Still Have to be Addressed
Precautionary 2060 With Flood Walls and 10-year/24-hour rainfall
Additional mitigations beyond flood walls along shorelines would be needed to prevent
street flooding should a significant rainfall occur during a storm surge event in the future
45
Copyright © 2014 Boston Water and Sewer Commission 980 Harrison Ave. Boston, MA 02119 617-989-7000
Update Design Storm for Drainage and
Conveyance Engineering, Planning and Design
• 10-year/24-hour design storm
– 5.20 inches (instead of 4.80 inches)
– Peak hourly intensity of 1.65 inches per hour
• For life cycles through the year 2100:
– Consider range from 5.55 inches to 6.65 inches
– Depending on the life cycle starting and end date.
• Other Recommendations
– Annual rainfall should range from 50.0 to 55.4 inches by the year 2100
– Apply to CSO control and TMDL planning
– Apply to operations and maintenance planning
– Continually monitor and update rainfall statistics
46
Copyright © 2014 Boston Water and Sewer Commission 980 Harrison Ave. Boston, MA 02119 617-989-7000
Design Flood Elevations (DFEs) to
Protect Facilities and Operations
Recommended DFEs for Pump Stations and other Structures
Project Life cycles up to the Year
(feet – Boston City Base)
Design Condition
2035
2060
2100
Minimum
18.22
19.06
21.16
Higher Risk Mitigation
18.88
20.11
24.50
Recommended DFEs are based on:
• The current MHHW elevation of 11.23 feet
• Sea Level Rise
• 100-year storm surge of 5.12 feet
• 1-foot freeboard
47
Apply to:
• Construction of new infrastructure
• Capital improvements to existing infrastructure
• Tide gates
Copyright © 2014 Boston Water and Sewer Commission 980 Harrison Ave. Boston, MA 02119 617-989-7000
New York City DEP
48
NYC Wastewater Resiliency Plan
 Strategy: Protect wastewater
treatment facilities
 Adopt a wastewater facility design
standard
 Harden pumping stations and wastewater
treatment plants
 Explore opportunities to expand
cogeneration
49
Critical Flood Elevations
50
26th Ward
12.6
13.5
12.9
Brooklyn-Sewer
Bowery Bay
11.6
15.5
13.9
Queens
Coney Island
10.1
15.5
14.0
Brooklyn-Highway
Hunts Point
10.2
17.5
16.0
Bronx
Jamaica
None
13.5
11.9
Queens
Newtown Creek
10.0
13.5
12.0
Brooklyn-Highway
North River
9.7
12.5
10.8
Manhattan
Port Richmond
12.1
14.5
12.4
Staten Island
Oakwood Beach
13.1
16.5
14.4
Staten Island
Owls Head
13.5
14.5
13.0
Brooklyn-Highway
Red Hook
11.7
14.5
13.0
Brooklyn-Highway
Rockaway
11.4
14.5
12.9
Queens
Tallman Island
10.1
15.5
13.9
Queens
Wards Island
10.7
17.5
15.8
Manhattan
Building-Level Risk Assessment
 Performed site visits and analyzed each facility for flood pathways and threshold
elevations.
 Locations identified as at-risk if threshold elevations are below the assigned flood
elevation (100-yr ABFE + 30-inches SLR).
Common Flood Pathways:
Rollup Doors
51
Tunnels
Doorways & Windows
Areaways
Grates
Electrical Conduits and
Manholes
Asset-Level Risk Assessment
 Target Assets include:
• Equipment associated with primary treatment
• Electrical equipment
• Pumps and motors
 Target asset identified as at-risk- situated below the assigned flood elevation
(100-yr ABFE + 30 inches SLR), and are not submersible.
Electrical assets located underground in
the RAS Gallery at 26th Ward WWTP are
at risk of flood damage.
52
NYCDEP Wastewater Resilience Plan Comparison of Mitigation
Costs and Cost of No Action (ie Benefits of Mitigation)
Adaptation Cost
No Action Cost
Risk Avoided Over 50 years
Source: NYCDEP
All 53estimates are based on AACE Level 5 Cost Estimate guidelines as noted in the NYCDEP BEDC Cost Estimating Manual
Thank You