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Infrastructure Resiliency Planning:
Keeping Downtown Economies Strong
Best Practices for Assessing Climate Risk from Extreme Rainfall Events
Laurens van der Tak
1
Today’s discussion
Why Consider Climate Risk for Downtown Facilities Climate Risk – a Primer Climate Scenarios and Uncertainty Examples
Why consider climate change for infrastructure planning and design? Road drainage, stormwater and wastewater facilities typically are
designed for selected peak design storms, estimated based on historical records
Extreme events consistent with climate change could alter these design criteria resulting in significant over- or under-design of facilities, creating unnecessary capital expense, or non-compliance with permits, and significant economic damage to communities
Businesses close as Duluth faces historic floodingMinneapolis / St. Paul Business Journal
June 20, 2012
What are extreme rainfall events?
Consensus definition: events that are “rare”
When they occur, can have catastrophic effects on human activities, infrastructure, and the environment
Source: Paul Davies, UK Met Office, 2009
Orchard Road, Singapore
Extreme rainfall events are becoming more frequent
Louisville, KY 2009: 5” in 90 minutes (1000-yr return interval is 3.83”/hour)
Washington, DC 2006: 11.3” in 6 days
Chicago, IL 2008: 6.7”in 1 day
Atlanta, GA 2009: 13” in 1day
Nashville, TN 2010: 13.6” in 2days
Duluth, MN, 2012: 10” in 1 day
Increases in Amounts of Very HeavyPrecipitation 1958 to 2007 (USGCRP 2009)
What do these changes mean for facility planners:What future conditions will affect the function of our downtown infrastructure and
what questions should planners ask:
Will changing storm frequencies change design storm criteria for transportation and stormwater conveyance facilities? – Could a "10-yr" storm be expected to become a "2-yr storm“? – What liabilities could result from these changes?
Will rising sea level impact facility siting and sizing? - Is your outfall going to be partially or fully
submerged more often?- Will your facility need to be flood-proofed or
moved?
Climate risk is just one among multiple risk factors to evaluate likelihood and consequence of facility failure
High
HighLow
ConsequenceLow
ProbabilityExisting Risk
Reduced Risk
Future Climate Risk
Other Future Risk
Net Future Risk
How do we ID and address these risks: Create future plausible scenarios and consider uncertainty: which GCMs, GHGs, and planning horizons???
Planning process should recognize that most underground infrastructure is expected to have a service life of 100 years or more, so consider:
Other plausible changes in the environment that could affect facility function– population, land use, possible technology changes, possible changes in regulations,
Projected climate change – climate in long term (2100 or later), or, climate in near term (2030-2050), can the facility
capacity can be expanded in phases
Creating portfolios of “no regrets” options that are customizable for range of possible future scenarios:– source control through green infrastructure, appropriate grey infrastructure, land use
planning, building codes that include flood proofing
Select a range of GHG emission scenarios to envelope or bookend potential climate uncertainty, ID suitable GCMs/ensembles (IPCC)
“Scenario Family” Description
A1 – Rapid GrowthA1FI - Fossil IntensiveA1T - Non-fossilA1B – Balanced
Second Highest Greenhouse Emissions
A2 – HeterogeneousHigh Population GrowthSlow Economic and Technology Change
Highest Greenhouse Emissions
B1 – Convergent WorldSame Population as A1, more service and information technology.
Lowest Greenhouse Emissions
B2 – Intermediate Population growth, local solutions.
Second Lowest Greenhouse Emission
A1FI
B2
A2
B1
A1T
A1B
Scenarios for GHG emissions from 2000 to 2100 in the absence of additional climate policies. (IPCC 2000)
Global Information• Changing Climate science• General Circulation Models• Emission Scenarios• lmpact assessment• IPCC Assessment Reports
Local Concerns • Defensible risk assessment• Temp and precip change• Catastrophic events• Sea level change• Adaptation effectiveness• Cost and timing
Large gap
How do we defensibly and efficiently translate global climate science to local impacts and wet weather planning action
Global-regional
scale
Local-national
scale
Climate science and scientists operate at global scale
Impacts, planning, and action are local
Local-national
scale
SimCLIM—an integrated modeling system for assessing climate conditions that influence risk and resilience for built and natural infrastructure and operations
Considers plausible, customized future scenarios for water, sea level and coastal issues, human health, ecosystems, agriculture, transportation, energy, and others
Incorporates local data for consideration of local impacts
A solution: a modeling environment to bridge the gap between global climate science and local impacts and action: SimCLIM
Global-regional
scaleGlobal-regional
scale
Local-national
scale
Storm sewer infrastructure planning with climate change risk: A Case Study—Alexandria Virginia
Experiencing repeated and increasingly frequent flooding events
Review of stormwater design criteria and projected impacts of climate change
Using SimCLIM projections and post processing for 2050 and 2100 to assess sea level rise; and rainfall intensity, duration, and frequency
Evaluating infrastructure adaptation options to reduce impacts from sea level rise and flooding from more intense and frequent storms
Hurricane Isabel flooding, September 2003Photo Credit: Mark Young/The Journal Newspapers
Projected Annual Precipitation (Reagan National Airport, DC)Reagan National Airport Projected Annual Precipitation
Median from 5 GCMs, 3 SRES Emissions (B1, A1B, A1FI)
35.00
40.00
45.00
50.00
55.00
60.00
1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
Year
An
nu
al
Pre
cip
itati
on
(In
ch
es
)
Median 5 GCM B1 (Low) Emissions
Median 5 GCM A1B (Medium) Emissions
Median 5 GCM A1FI (High) Emissions
55.9” +44%
52.2” +35%
47.3” +22%
38.8”Total Precipitation projected to increase by 22 to 44% -
Alexandria Virginia: Change in Rainfall Frequency
Daily Rainfall Extremes – Intensity and FrequencyA1FI (highest), 12 GCMs
The intensity of a 10 year event will be 15% higher by 2050
16
Best practices for assessing climate risk from extreme rainfall events for drainage infrastructure and downtown businesses
Consider range of plausible futures and risks Integrate climate risk with overall risk assessment Recognize service life of infrastructure Consider uncertainty by factoring in:
– An envelope of GHG emission scenarios (low, medium, or medium-high, high)– A range of GCM models (downscaled to project scale)
Use a science-based, updatable, efficient tool set to implement this approach for defensible outcomes and implementable solutions
17
Options for building resilience
Planning Avoidance Green Infrastructure
– Green Streets & Alleys– Green Parks– Green Parking Lots– Vegetated Roofs– Enhanced Tree Planting– Green Schools & Public Facilities
Detention Systems Flood proofing Emergency preparedness
Permeable pavement options fit into downtown streetscapes
19
Detention systems can be multifunctional in downtown urban areas
Storage Pond used to Attenuate Storm Run-off in a New Development in Netherlands.
Dual-use Detention Storage Area in an Urban Community in Malmo, Sweden
20
Floodproofing can protect high value assets from infrequent but potentially damaging floods
Retrofitted rising flood barriers along Orchard Road, Singapore.
21
Source: Climate Adaptation and Transportation, CCAP, May 2012
Infrastructure Resiliency Planning:
Keeping Downtown Economies Strong
Best Practices for Assessing Climate Risk from Extreme Rainfall Events
Laurens van der Tak
22