A GUIDE FOR USAID PROJECT MANAGERS

BRIDGESINCORPORATING CLIMATE CHANGE ADAPTATION IN INFRASTRUCTURE PLANNING AND DESIGNNOVEMBER 2015

ADB South SudanXX

ACKNOWLEDGMENTS

This guide was developed for the United States Agency for International Development (USAID) by AECOM as part of a series of sector specific climate change
adaptation manuals prepared for the USAID-funded Global Climate Change, Adaptation, and Infrastructure Issues Knowledge Management Support Project.

COVER PHOTOS

The image on this page shows the rehabilitation of a bridge in South Sudan with steel for longevity and climate proofing (credit: ADB South Sudan).

DISCLAIMER

The authors’ views expressed in this document do not necessarily reflect the views of the United States Agency for International Development or the UnitedStates Government.
E.1

EXECUTIVE SUMMARYXX

GLOBAL CLIMATE CHANGE,
ADAPTATION, AND
INFRASTRUCTURE ISSUESKNOWLEDGE MANAGEMENTSUPPORT
CONTRACT NO. EDH-I-00-08-00023-00
ORDER NO. OAA-TO-12-00057
NOVEMBER 2015SUBMITTED TO:

PREPARED BY:XXA METHODOLOGY FOR INCORPORATING CLIMATE CHANGE

ADAPTATION IN INFRASTRUCTURE PLANNING AND DESIGNBRIDGES

E.3

EXECUTIVE SUMMARYCONTENTSXXACRONYMS...........................................................................................................................................................................ii
KEY TERMS............................................................. ............................................................................................................ iii
EXECUTIVE SUMMARY.................................................................................................................................................... E.1
CHAPTER 1: INTRODUCTION.......................................................................................................................................... 1.1
Bridge Infrastructure...................................................................................................................................................... 1.1
Climate Change Impacts on Roadway Infrastructure.................................................................................................... 1.1
How to Use This Guide................................................................................................................................................. 1.2
CHAPTER 2: CLIMATE IMPACTS AND RISKS................................................................................................................. 2.1
Climate Impacts and Risks to Bridges Infrastructure Design........................................................................................ 2.1
Key Considerations in Identifying Impacts to Bridges................................................................................................... 2.2
Key Considerations....................................................................................................................................................... 2.2
Large-Scale Bridges...................................................................................................................................................... 2.3
Potential Impacts on Small-scale Bridge Infrastructure................................................................................................. 2.4
CHAPTER 3: A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGY................................................................ 3.1
Enabling Climate Resilient Planning and Design of Bridge Infrastructure..................................................................... 3.1
Step 1: Establishing the Context.............................................................................................................................. 3.3
Step 2: Vulnerability Assessment............................................................................................................................. 3.5
Step 3: Risk Assessment.......................................................................................................................................... 3.8
Step 4: Developing an Adaptation Strategy............................................................................................................ 3.12
Step 5: Implementation.......................................................................................................................................... 3.15
CASE STUDY.................................................................................................................................................CASE STUDY-1
SUGGESTED RESOURCES........................................................................................................................ RESOURCES-1
ANNEX.....................................................................................................................................................................ANNEX-1
REFERENCES.............................................................................................................................................REFERENCES-1i

ACRONYMS
XX

ADB		

Asian Development BankCAPEX		

Capital Expenditure

CBA		

Cost-Benefit Analysis

IPCC		

Intergovernmental Panel on Climate Change

MCA		

Multi-Criteria Analysis

OPEX		

Operational Expenditure

PPTA		

Project Preparation Technical Assistance

SSH		

Second Southern Highway

USAID		

United States Agency for International Developmentii

KEY TERMSXX

ADAPTIVE CAPACITY, as it relates to infrastructure and built assets, describes the degree to which the physicalelements of a system can absorb, withstand, or respond to climate change impacts without incurring damage.
CLIMATE is an expression of the composite weather conditions (e.g., temperature, precipitation, wind), including both
statistical averages and the occurrence of extreme events, over a given period of time. The World MeteorologicalOrganization recommends a 30-year period to adequately describe the climate of a given area.
CLIMATE CHANGE refers to a statistically significant variation in climate data or patterns over a given period of time, due
to either natural climate variability or as a result of human activity.
CLIMATE CHANGE ADAPTATION describes measures taken in response to actual or projected climate change in order
to eliminate, minimize, or manage related impacts on people, infrastructure, and the environment.
CLIMATE CHANGE MITIGATION refers to actions that reduce the production of greenhouse gases that cause climatechange. Although some adaptation strategies have mitigation co-benefits, they are not specifically referenced in thisguide.
CLIMATE CHANGE IMPACTS on infrastructure are, for the purposes of this guide, the resulting influence of climatechange effects on the structural form or function of an asset (e.g., the buckling of train tracks due to extreme heat).
CLIMATE CHANGE VARIABILITY is the short-term fluctuation in weather conditions, usually over a period of a year or a
few decades.
CLIMATE DRIVER is the manifestation of a change in climatic conditions through one or more weather variables, such asa change in precipitation or sea level rise, to create an impact.
EXPOSURE refers to the extent to which a system comes into contact with a hazard.
LARGE-SCALE INFRASTRUCTURE SYSTEMS serve large populations and tend to be focused on urban areas.
RISK is the combined function of the likelihood that a hazard will occur and the resulting consequences.
SENSITIVITY is the degree to which a built, natural or human system is directly or indirectly affected by or responsive tochanges in climate conditions or related impacts.
SMALL-SCALE INFRASTRUCTURE SYSTEMS service smaller populations, ranging from villages to clusters orcommunities of households, and are often more relevant to rural areas.
VULNERABILITY is the degree to which a system is susceptible to or unable to cope with adverse effects of climatechange, including climate variability and extremes. It is often defined as a combined function of exposure and sensitivity to
the effects of climate change, minus the adaptive capacity of a system.

iii

AECOMXX

Bank protection, Padma Bridge, Bangladesh

EXECUTIVE SUMMARYXX

Extreme weather events such as
droughts, heat waves, dust storms,
forest fires, floods, and landslides,
which already disrupt the lives of
millions each year, are expected toincrease in frequency and intensitywith climate change. The impact ofthese sudden events, in addition
to the gradual change in climate
effects over time, will put added
stress on vital water, sanitation, flood
management, transportation, andenergy infrastructure. Responding to
the impacts of climate change presents
a major challenge for developing
countries lacking adequate resources,
and it is therefore an important focusof the United States Agency forInternational Development’s (USAID)
development assistance portfolio.
To help address this challenge,
and consistent with Executive
Order 13677 – Climate-Resilient
International Development, USAID
has developed the Global Climate
Change, Adaptation, and Infrastructure
Knowledge Management Support
Project (a Task Order under theArchitecture and Engineering Indefinite
Quantity Contract or IQC) to articulate
best practices in incorporatingclimate adaption in the planningand engineering design of USAID
infrastructure activities.

Under this project, a suite ofknowledge management products
has been created, led by theOverarching Guide: A Methodology
for Incorporating Climate Change
Adaptation Infrastructure Planningand Design. The objective of theOverarching Guide is to support theconsideration of climate change risks
and adaptation in USAID infrastructuredevelopment activities. Serving as atechnical companion volume to the2014 USAID publication, Climate
Resilient Development: A Framework
for Understanding and Addressing
Climate Change, the Overarching
Guide provides engineering and nonengineering development professionals
with a methodology to evaluate
infrastructure vulnerability and selectappropriate engineering design options
to rebuild resilience.
As part of the suite of tools forincorporating climate resiliency into
engineering design, this particular
guide focuses on bridge infrastructure,with the overall objective of supportingthe consideration of climate changerisks and adaptation in USAID bridge
infrastructure development activities.
All transportation infrastructure,including roads and bridges, aresensitive to weather and climatechange. Climate change affects

the planning, design, construction,
maintenance, and performanceof these structures throughout
their service life. For developing
nations, due to the lack of funding or
technical expertise, climate change
adaptation may not be incorporated
into the decision-making process.
However, impacts of climate changeon transportation infrastructure canproduce significant damage with highcost implications, therefore climatechange should be incorporated early
on in the investment decision process.
This guide will be useful for thoseconsidering specific engineering
design options to make bridge
infrastructure more resilient in a
climate altered future. It provides
engineering and non-engineeringdevelopment professionals with an
overview of potential impacts on bridge
activities and adaptation options, andguidance for utilizing a risk assessment
methodology to determine appropriate
design measures.
While the focus of this guide ison engineering design; broader
elements such as service delivery
and management of supply anddemand are also proposed as they areclosely associated with the optimum
performance of bridge infrastructure.

A SUITE OF TOOLS
Accompanying this bridges guide are additional primers that focus on flood management, potable water structures, sanitation, roadways, and irrigation, that provide more detail on
climate change impacts and appropriate adaptation responses and strategies for these other important infrastructure sectors.

EXECUTIVE SUMMARY

E.1

The focus of this document is
not on mitigation of greenhousegas emissions related to bridge
infrastructure construction or operation.

THE IMPORTANCE OFCONSIDERING CLIMATECHANGE IMPACTS IN BRIDGEINFRASTRUCTURE
It is important for practitioners andstakeholders to consider the natureand extent of climate change impacts
on investments and activities, including
activities related to both new andexisting infrastructure.
Bridges are often built crossing water
bodies, exposing the structure toclimate hazards including erosion,flood events and associated changes
in long-term flow regimes. The
potential losses, either in term of
human or economic capital that
could occur due to the collapse of,or damage to, bridges are great.
Therefore, it is necessary andimportant to consider climate change
in bridge design. Climate change
is likely to cause damage, reduce
performance, and limit the accessibilityof bridges.
Typically bridges are designed
using design criteria that have been
calculated from historical climate
data under the assumption that the
average and extreme conditions of
the past will represent conditions overthe future lifespan of the structure. In
the context of climate change, these
designs will need to be reassessed,
and updated to reflect changing
climate risks. In addition, the inherent
uncertainty associated with projecting
climate change is likely to bring about
additional challenges to the design,
construction, and operation of new
infrastructure.

When considering the impact of climatechange on bridge infrastructure,
it is important to understand therelevance and cost-effectiveness ofclimate change adaptation activities.
If the infrastructure asset is a shortterm or temporary solution, it islikely unnecessary to fully assess
longer term climate change risks to
the investment. If the asset is large
or expected to last more than three
decades, climate change risks should
be considered.

A STEPWISE APPROACH TO
CLIMATE RESILIENT DESIGN

Following a climate resilience
framework when developing andevaluating bridge infrastructure
design will help practitioners
improve the effectiveness of theseinvestments. USAID’s Climate
Resilient Development Framework1
promotes the adoption of development
strategies and infrastructure activities
that integrate risk considerations inorder to create more climate resilient
infrastructure and thereby enhancecost effectiveness of interventions.
These goals can be realized byfollowing a five-step approach to: 1)
establish the context; 2) conduct avulnerability assessment; 3) conduct
a risk assessment; 4) develop an
adaptation strategy; and 5) implement
activities in support of climate resilient
infrastructure (addressed in Chapter
3).
This framework should be used bypractitioners to establish what climatechange impacts existing or proposed
infrastructure assets might be facing(e.g., sea level rise, flooding, drought,
and more extreme heat days); whether
or not the asset might be sensitive
to those changes; and how suchsensitivities impact the asset. The

subsequent risk assessment will help
identify those assets whose failure
would have significant impacts onbuildings, economic activities, or publichealth. Adaptation strategies should
then be defined and implemented.

ADAPTATION STRATEGIESAND RESPONSES
Responding to climate change impacts
will require the selection of appropriate
adaptation strategies. These strategies
should be selected based upon theprevious assessments conductedunder the Climate Resilient Design
Methodology (see Chapter 3) and take
into consideration a country’s priorities,
availability of resources, and temporalscale of the activities.
The diverse array of adaptation
strategies and responses for enabling
more climate resilient infrastructure
design can be categorized underfour types of strategic approaches:
1) accommodate and maintain; 2)harden and protect; 3) relocate; and4) accept or abandon. Each approach
has advantages and disadvantages
that are expanded upon in Chapter 3.
Examples of climate impacts and risks,
and adaptation measures relevant tobridge infrastructure are provided inTable 1.
A compendium illustrating adaptation
strategies available to practitioners
to address potential climate changerelated risks to bridge infrastructure isalso provided in the Annex.

CASE STUDY
A climate change resilient infrastructure
design case study is also provided
to demonstrate the application of themethodology presented in this guide.

USAID. 2014. Climate-Resilient Development: A Framework for Understanding and Addressing Climate Change. Washington, D.C., available at http://www.usaid.gov/climate/climate-resilient-development-framework

1

E.2

EXECUTIVE SUMMARYXX

TABLE 1: EXAMPLES OF BRIDGE INFRASTRUCTURE RISKS AND ADAPTATION MEASURES
Climate Drivers

Drought, Reduced Average
Precipitation, Increased
Surface Water Temperature,
Wildfires

Extreme Precipitation Events,
Less Frequent but Higher
Intensity storms, Flooding

Climate Impacts and Risks

Adaptation Measures• Higher temperatures and extreme heat can cause
bridges to be stressed by thermal expansion andmovement and lead to premature deterioration of
the structure• During winter periods, the greater daily variability
and range of maximum and minimum temperature
can generate more frequent freeze-thaw conditions
which may damage bridge joints• Wildfires may be a hazard for bridges made outof timber in the areas impacted by heat waves anddrought• Replace or reconstruct bridge deck expansion joints
to mitigate the impacts of higher temperature• Use paving materials that are more resistant toexpansion in extreme heat conditions• Build small-scale bridges with heat resistantmaterials or use coatings• Maintain and implement vegetation management
practices that aim to minimize fire risk

Increased frequency of extreme precipitation events
increases the risk for flooding, which can reduce theservice life of bridges by:• Protect bridges from damages caused by flooding bystrengthening the bridge piers and foundations, orby increasing the hydraulic capacity of the bridge by
raising the bridge deck
• Minimize the occurrence of flooding or reduce
its magnitude by increasing infiltration within
the catchment area draining through the bridge
structure, or diverting high flows to drainage
systems with a higher drainage capacity• Increasing the scouring rate of piers and bridgefoundations, and build-up of sediments• Increasing moisture levels in soil that may lead toloss of structural foundation integrity• Small-scale bridges are more vulnerable since they
are often not designed to withstand powerful floods
or strong wind
Both sea level rise and storm surges can:Sea Level Rise, Storm Surge• Damage bridges and connected roadways due
to flooding, inundation, and erosion of land that
accommodates infrastructure• Decrease expected lifetime of bridges• Result in scour by eroding riverbeds and exposing
piers and bridge foundations• Protect bridges from powerful storm surges andwaves by reinforcing piers, columns and bridgefoundations against scouring• Raise bridge deck
• Treat metal components of the bridge to resist
corrosion due to increased exposure to salinity

EXECUTIVE SUMMARY

E.3

XX

XX
CHAPTER1

INTRODUCTION
BRIDGEINFRASTRUCTURE

compromised, walks to school, work,
Climate change is aor health facilities can become life
significant threat tothreatening. Without a reliable, efficient
Bridges are a central component ofand well-maintained transportationpoverty reduction
every nation’s transportation system.
system, including bridges, a country
Bridges can be categorized in several
activities and could
will not be able to maximize its
ways. Common categories include theeconomic potential. Often, the absence
jeopardize decades ofstructural type, their primary usage,of reliable bridges are placing people atwhether they are fixed or movable, anddevelopment efforts.
risk in most developing countries, andby the materials used in construction.
isolating them from accessing basic
From the very beginning
By structure type, bridges are classified
human needs and from participating inas beam, truss, cantilever, arch,of the investment plans
the economy.
suspension, cable stayed, fixed andand the design process,movable, double-decked and viaduct,
and those made up of multiple bridges
development of new
CLIMATE CHANGE
connected into one longer structure.
infrastructure andIMPACTS ON ROADWAY
Bridge structures are most commonly
constructed with concrete, steel, fiber
rehabilitation of existing
INFRASTRUCTURE
reinforced polymers, stainless steel
Climate change will likely exacerbate
infrastructure should be
or combinations of those materials. In
existing roadway issues andaddition, many bridges in developing
designed to be resilient
further deteriorate the condition
regions are made of timber materials.
of bridges in both developed andto climate risks.
Bridges serve many purposes,
developing countries. In 2014, theincluding connecting residents with
Intergovernmental Panel on Climate
jobs and businesses with commerce
Change (IPCC)2 concluded theareas that would otherwise be isolated. following:
Bridges provide isolated communities• The effects of climate change will
• Sea level rise will most likely reachwith access over impassable
continue even if greenhouse gas
40-63 centimeters during the 21stlandscapes to essential health care,
concentrations were to stabilize at
century.
education and economic opportunities.
existing levels; average temperature
There is a nexus between availability• In most regions, there will be moreincreases and sea level rise willof transportation systems and poverty.
instances of hotter, and fewer
continue due to the timescales
The need is to create greater access toinstances of cold temperatureassociated with climate processes
employment opportunities, educational
extremes as global mean
and feedback effects.
and health facilities, agricultural
temperatures increases.
development, social inclusion• Global mean temperature may riseand networking. Rural community
between 1.0oC to 3.7oC by the end
members, who typically live in remoteof 2100, according to various climate
areas, rely heavily on safe walking
change scenarios and models.
routes. However, when rivers swellduring rainy seasons and bridges are

2

Intergovernmental Panel on Climate Change (IPCC). 2014 Fifth Assessment Report http://ipcc.ch

INTRODUCTION

1.1

Transportation infrastructure, suchas bridges, is vulnerable to extremes
in precipitation, temperature, andstorm surges, which can damage
the structure and roadway deck ofbridges. For example, if soil moisturelevels become too high with increased
precipitation, the structural integrityof aged or weak bridges could becompromised. Gradual increases inextreme rainfall events and damaging
storms increase the risk of flooding,causing bridge closures, as well as
the need for repair and reconstruction.
Amplified extreme temperatures affectthe thermal expansion and movementof joints, and therefore increase stresson bridges. The greater variability
and range of maximum and minimum
temperature can generate more
freeze-thaw conditions and damage
bridge expansion joints. Any increasein the intensity of storm surges arelikely to increase, causing more
frequent or severe flooding of low-lying
infrastructure and scouring bridgefoundations due to eroding riverbeds.
Future bridge structures will haveto adjust for the direct and indirect
impacts from climate change. If theserisks are not carefully considered in
new construction activities, they could
prevent emerging countries fromcontinuing their economic and social
development.
Design guidance revision is necessary
to provide more robust bridges in the
future. Revising existing guidelines
requires changes to design criteria,
including considerations for new
and higher traffic loads, stronger
foundations, and greater freeboard
between the water level and the bridge
surface.

HOW TO USE THISGUIDEThe overall objective of this guide isto support the consideration of climatechange risks and adaptation in USAID
bridge infrastructure development
activities. This guide provides
engineering and non-engineeringdevelopment professionals with a
guidance document demonstrating a
step-by-step method for assessments
and supporting technical information,
including an overview of potential
impacts on bridge activities, adaptation
options, case studies and resources.
This guide will be useful for thoseconsidering how climate change may
require specific infrastructure projects
to be altered to enhance resilience.
This guide will also be useful to thoseconsidering how to meet service goals
in a climate altered future.
This bridges guide accompanies
an Overarching Guide that covers
integration of climate change
adaptation considerations into a
broad range of USAID infrastructure
activities. The overarching
methodology offers a step-wiseprocess for implementing a risk
assessment framework. This guide is
specific to bridge infrastructure. Notethat some content is repeated in bothguides to maintain readability of eachdocument.

To provide effective guidance, thisguide differentiates between large- andsmall-scale bridges based on the typeand level of use of the roadway, which
dictates the available engineering
design options.
• Large-scale bridges are generally
operated for multi-modal vehicles
and are sometimes shared withpedestrians (equipped with orwithout sidewalks on one or bothsides). Large-scale bridges typicallyrequire considerable capital
investment to design and construct
due to the larger scale and length,
as well as larger operational costs tomaintain. They often function as partof major evacuation routes, usually
across a water body; and• Small-scale bridges, on the other
hand, typically have a short-span,
low automobile volume, smallerscale and length, and are often
operated solely for pedestrian, or
motorcycle and motor-bicycle usage.
They are often predominant in rural
areas and do not require extensive
capital investment or maintenancecosts. They can often be built andmaintained with local materials andbasic technical skills.

This guide addresses climate change
adaptation rather than mitigationof greenhouse gas emissions. The
focus of this guide is on engineeringrelated activities, such as design andconstruction. However, non-technicaladaptation considerations, such as
managing traffic loads during certain
times of the year, are also included inthis guide as a means to further protect
transportation systems from climatechange impacts.

GEOGRAPHY
When considering adaptation to climate change, it is very important to remember that the effects of climate change vary geographically. Location is a key factor because regions
around the world are affected differently by climate change. For instance, sea level is predicted to rise worldwide, yet the rate of which it is rising varies globally. Development of
a new bridge, or reinforcement of an existing structure, needs to be designed in a way that is resilient to anticipated climate change impacts for the specific location. To be mosteffective, local climate projections need to be considered at the early stages of planning and engineering design.
1.2

INTRODUCTIONXX

DeNatale, AECOM

Mozambique

INTRODUCTION

1.3

AECOM

XX

Dredging, Padma Bridge, BangladeshCHAPTER 2

CLIMATE IMPACTS AND RISKS
CLIMATE IMPACTS
AND RISKS TO BRIDGEINFRASTRUCTURE
DESIGN

conditions, resulting in an increase ofgirls attendance in school. Improved
road access has also been shown tosubstantially increased health carefacility use. Despite this value, reliablebridges and roadways with sufficient
Bridges are an integral part of theconnectivity to jobs and community
transportation system of a country.
resources are still lacking in developing
Only with an efficient and wellconnected road network, transportation countries because of inadequate
investment and maintenance.
services, and well- maintained
bridges can a country maximize
The development of new infrastructure
its economic potential. Investing inand the renewal and maintenancebridges and transportation systemsof existing assets will increasingly
make it easier for those located in
be impacted by climate change.
remote areas to transport goods,
Consequently, it will be critical thattravel long distances, and gain accesspractitioners understand how naturalto improved developments, such as
hazards and the changing climate
electricity and clean drinking water.
will likely impact infrastructure assets
Better-quality bridges and roadand services in order to assess
access also support advancement inrisks and make informed decisions
social infrastructure. Positive impacts
regarding asset design, operation andhave been documented in countries
maintenance.
such as Morocco, where improved
road access created safer traveling

The primary climate drivers referenced
in this guide are identified below .
Icons are provided for each climate
driver and are used as visual aids
throughout this guide. Additional
natural hazards that are not explored inthis guide but may affect infrastructure
include tsunamis, earthquakes,
volcanic eruptions, landslides androckfalls. The following sections
provide an overview of the risks thatclimate change may pose to bridges,
and how to manage or minimize theserisks in the development, maintenanceor rehabilitation of bridge infrastructure.
The range of risks discussed is not
exhaustive; practitioners should
conduct a detailed assessment at the
project or program level to identify all
relevant risks.

CLIMATE DRIVERS

EXTREME HEAT/HEATWAVES:
Extremetemperatures arelocation specific.
Heatwaves areprolonged periodsof excessively hot
weather. Likely
increase in extreme
air temperature andheatwaves in mostareas.

DRYING TREND/
DROUGHT:A prolonged dry
period in a natural
climate cycle
which results in ashortage of water.
Likely increase indrought conditions
in some areas
through a warmingof air temperatureand decrease inprecipitation.

EXTREMEPRECIPITATION/
FLOODING:
Extremeprecipitation eventsare location specificand can cause
flooding when
downpours exceed
the capacity of riveror urban drainage
systems. Uncertain
climate projections,
expected to intensify
in some areas.

STORM SURGE:
The difference
between the actual
water level under
the influence ofa meteorologicaldisturbance (stormtide) and the level
which would havebeen attained in
the absence of themeteorologicaldisturbance (i.e.
astronomicaltide). Sea level rise
exacerbate storm
surge height.

SEA LEVEL RISE:
Anticipated sea levelchanges due to thegreenhouse effectand associated global
warming. Leads tochanges in erosion
and accretion, longterm inundation,
exacerbate storm
surge and tsunami
height.

DAMAGING
STORMS (WIND,
LIGHTNING):
Severe weather
systems involving
damaging winds
and heavy rainfall
downpour, including
tornados, hailstorms,
tropical cyclones andhurricanes. Uncertain
climate projections.

WILDFIRE:
A massive anddevastating fire
which destroys
forests, grasslands
and crops, kills
livestock and wild
animals, damages ordestroys settlements
and puts lives of
inhabitants at risk.
Uncertain climate
projections.

CLIMATE IMPACTS AND RISKS

2.1

KEY CONSIDERATIONSIN IDENTIFYINGIMPACTS TO BRIDGES

Climate change is likely to impact
bridge infrastructure assets throughmodification in the pattern of extreme
climatic events, which includes
storms and storm surge, floods, anddrought; or through gradual changes
in seasonal or annual patternsof temperature, solar radiation,
precipitation, and sea level rise.
When evaluating the impact of climatechange and risk to bridge infrastructure
there are two overarching concerns– the timeframe for the asset’s
productive lifespan and required capitalcosts. While engineering design always
considers some measure of extreme
weather conditions when designingor rehabilitating infrastructure, it isimportant to consider a temporal scalethat is appropriate to the anticipatedlife of the asset as well as and costeffectiveness of climate resilience
options.

KEY CONSIDERATIONSIn developing countries, climate
adaptation measures will be required
to reduce the costs and disruption
caused by climate change. Keeping in
mind the key aspects noted above, itwill also be important when designingor rehabilitating infrastructure systems
to follow certain principles that will help
create greater resiliency by planning
not just for the current climate, but forthe climate scenario projected for theentire design life of the infrastructure
asset.
Impacts are a function of current
and future climate variability,
location, asset design life, function,and condition. Many characteristicsof the asset and its location influence
the likelihood and extent of climate
impacts. These characteristics must
be considered when establishing thecontext for the climate change risk andvulnerability assessment. Questions
2.2

CLIMATE IMPACTS AND RISKS

about the condition of the existing
asset base (Has it been maintained?
What is its current failure rate?) are
important to evaluate as part of acomprehensive assessment.
Climate change can cause direct
physical impacts to assets andindirect impacts including loss ofservice. Changes in the pattern ofextreme events can directly impact
the physical integrity of built structuresin a variety of ways, causing loss ofservice. One way climate change
impacts bridges is through flooding andscouring around bridge foundations
due to increased intensity andfrequency of heavy rainfall. Collapsesof bridges due to flooding can also
occur. In the future, flooding is
expected to occur more frequently andbe more destructive in many regions.
Current infrastructure designis based on historical dataand experience. Most existing
infrastructure assets were designed
based on historical climate data,such as average rainfall and runoff
in an area, or historic flood events.
However, the pace of climate changemeans that historic data may nolonger be relevant for longer-term
infrastructure performance. Climatechange may cause shorter asset lifespans or require early rehabilitation as
infrastructure degradation accelerates.
These situations can be exacerbatedin less developed countries, where
design standards and climate
information may be out of date or
nonexistent.
For new assets, both the locationof the asset and the functionalclassification of a bridge based on
performance characteristics (e.g.,traffic flow and performance of abridge, as well as vehicular traffic
and pedestrian usage) should takeclimate change into consideration.
The associated impacts of climatechange on transportation infrastructure
will vary regionally, reflecting

differences both in the magnitude ofclimate change, and in environmental
conditions. Asset location isparticularly relevant in coastal areas
and floodplains. The capability of theasset to perform to its level of design
may be impacted by changes in theenvironment.
Uncertainty in climate projections
should not prevent them frombeing considered in design. Whenconsidering the design of an asset,
the question of how high or how big
is critical and not easily answeredwith available climate projections.
To help overcome this, consider
the implications of failure. If it iscritical that there be no interruption
to service then consider the upperbounds of the possible risk (i.e. worst
case climate projections) would be
prudent. Alternatively, consideration
should be given to the marginal costs
and benefits of a design decision.
Sensitivity testing of a design’s relative
costs and benefits may show that therisk management benefits from a larger
pipe, or higher asset, may significantly
out-weigh the marginal cost.
Demand for services can shift asa result of climate change. Warmer
temperatures and more frequent heatwaves can lead to physical damage
for some bridges and consequently
increase usage for other undamaged
bridges, if available. Demographic
expansion or contraction, such as
the relocation of coastal communities
affected by flooding and sea level rise,
may affect the demand for services.
Indirect impacts and cascading
consequences can be more difficult
to identify than direct impacts, butthey should be considered. For
example, the location of populationand human activity can be affected byclimate change and alter the demandfor bridges. If demand is likely tochange, then the consequences need
to be considered in future designs.

LARGE-SCALE BRIDGESFor large-scale bridges, a major
climate change risk is an increase
in intensity and frequency of heavy
rainfall, which can result in greater
flooding and scouring around bridgefoundations. Large-scale bridges,
especially those that span several
hundred meters over a large water
body, are very vulnerable to riverflooding (if located inland) or storm
surges and waves (if located near thecoastline). The destructive energy,
wind, precipitation and storm surges
associated with hurricanes andtyphoons are likely to increase in thiscentury. Sea level rise, increased
frequency of storm events, andincreasing extreme temperatures, area few of the climate drivers that canhave serious impacts on large-scale
bridge structures.

Scour. Hydrologists and structural
engineers have studied scourfor decades, and it is a central
consideration in bridge design. In
Flash Floods and Extended
Flooding Conditions. When a swollen the 1990s, several bridges collapsed
due to bridge scour in the United
river passes under a bridge during
States; these collapses occurred ina flood event, the high water level
different regions and under different
can cause debris to come in contacthydrological conditions, highlightingwith the bridge. If the impact doesn’t
the potential for scour to occur underdamage the bridge immediately, theweight of the piled-up debris combined many streambed conditions. Scouris a process involving the erosion ofwith the force of the flowing water
streambed or bank material due topushing on it can cause the bridge toflowing water at or around piers andcollapse.
foundations. Scour causes stabilizing
material, (e.g. the streambed or
Hurricanes and Tropical Stormsbank) to move away from the bridge
are Becoming More Powerful. As
substructure, causing instability of thehurricanes are expected to increase
bridge’s foundation. Climate change
in intensity (and frequency in somewill likely increase the intensity of river
regions), bridges may encounter
flows and exacerbate bridge scour.
stronger and more powerful storm
Extensive damage associated withsurges and waves causing directscour can cause a bridge to collapse.
physical damage.

IMPACTS FROM EXTREME
PRECIPITATION EVENTS AND
DAMAGING STORMS

USAID HAITI ENNERY BRIDGE DESIGN AND RECONSTRUCTIONUSAID ECO-ASIA

The 2008 rainy season in Haiti was particularly strong
toward the end of August, with four major storms andhurricanes hitting Haiti over a four-week period. Haiti’stransportation system sustained severe damage as aresult of these storms, including the collapse of the
Ennery Bridge caused by erosion and scouring of thebridge footing.

CLIMATE IMPACTS AND RISKS

2.3

3

USAID AFGHANISTAN ALPPOTENTIAL
IMPACTS ON SMALLSCALE BRIDGEINFRASTRUCTURE

Both small-scale and large-scale
bridges are affected by climate changevery similarly, although small-scale
bridges are generally much weaker
and therefore more susceptible toclimate change. Since small-scale
bridges are typically designed andbuilt with local labor or materials, they
are often subjected to lower standards
and requirements. The condition ofthis type of bridge may be relatively
poor even without the effect of climatechange. This is especially true indeveloping countries, where there
is often limited financial support andrestricted regional or local government
involvement.
Impacts and risks associated withsmall-scale bridges are described infurther detail in this section.

AECOM SOUTH AFRICA ROAD AGENCY

are subject to many modes of heattransfer and variation in the average
daily temperature can cause bridges
Climate change is expected tocontribute to more rapid sea level rise. to extend or shorten. Although theeffect is minimal in the short-term, theAlthough the rate varies globally, on
impact can be cumulative and reduceaverage sea levels worldwide havebeen rising at a rate of 0.14 inches (3.5 the service life of a bridge, increase
the costs of bridge inspection,
millimeters) per year since the early
1990s.2 Sea level rise impacts bridges maintenance and repair.
through the increased frequency ofGreater variability and range offlooding, which can worsen bridge
maximum and minimum ambient
scour. An increased rate of bridge
temperatures will also cause anscour can weaken the structure and its
increase in freeze-thaw cycles, which
service life, and lead to more frequentcan damage bridge expansion joints.
and extensive repair.
However, the impact of increase infreeze-cycles is mostly relevant to
Storm Surge and Waves. Storm
colder climate regions.
surge is caused by strong winds
and pressures, which lead to a rise
Degradation of the Bridge Deckin water surge. Storm surge during
Material. Most large-scale bridges are
powerful storms or hurricanes canbuilt with asphalt or concrete pavement
3
reach over 20 feet in elevation andsurfacing bridge decks. One reason for
can cause significant damage tousing asphalt layers is to protect thebridges. Additionally, waves are morebridge deck structures from water, dirt,
powerful and have higher arches,
de-icing agents, or other intrusions.
which can cause considerable damage
Asphalt pavement can experience
to bridges. Since most infrastructure
softening and traffic-related rutting, as
design is based on historical datawell as the migration of liquid asphalt
and experience, the asset design isto the bridge deck surface from older
not always capable of withstandingor poorly constructed pavements
such impacts. For instance, Hurricane
as well as resurfacing maintenanceKatrina, one of the deadliest andof the deck material. Asphalt rutting
destructive hurricanes in the history of
may become a larger problem during
the United States, damaged the Twin
longer periods of summer heat on
Span Bridge by lifting many of the 225roads with truck traffic, whereas someton concrete bridge spans off of their
bleeding or flushing could occur withpiers.
older pavements or those with excess
asphalt content. These problems
should be avoidable with proper
IMPACTS FROM INCREASE IN
design and construction, but at a cost.
AVERAGE TEMPERATURE AND
More information on climate impacts
EXTREME HEAT
to pavement surfacing is available inDamage to Expansion Joints. Under USAID’s “Roadways: A Methodology
current climate projections, extreme
for Incorporating Climate Change
heat events and heat waves are
Adaptation in Infrastructure Planninglikely to become more frequent and to
and Design.”
last longer than in the past. Bridges

IMPACTS FROM SEA LEVELRISE AND STORM SURGE

Prior to improvements, Grobler’s
Bridges were not capable ofwithstanding the rising water levels
common to South Africa’s lowland
river basin and would overflow,marooning the island’s communities
for months at a time.

NOOA, National Hurricane Center: Storm Surge overview. Retrieved from http://www.nhc.noaa.gov/surge/ on September 9, 2015

2.6

CLIMATE IMPACTS AND RISKSINCREASED FREQUENCY OF
EXTREME WEATHER EVENTS

A major concern for small-scale
bridges is the predicted increased
frequency of extreme weather events
involving damaging winds and heavy
downpours, including tornadoes,
hailstorms, tropical cyclones andhurricanes.
Shorter But More Intense
Precipitation Events Causing
Flash Floods. Increased frequencyof heavier short duration rainfalls are
expected to cause more frequent andsevere flash floods. If a bridge is built
over a river, the depth of water passing
under the bridge may raise to a heightthat has not been recorded before.
Higher flow rates can create erosion
and carry debris (large boulders andtrees) that can create dams behindbridges or directly impact the footingsof the bridge and cause it to collapse.
The image below shows an example
of a collapsed and washed out river
bridge due to a powerful flood event.

Increased Intensity of Hurricanes
and Tropical Storms. One of thedirect results of more powerfulhurricanes and tropical storms isstronger wind. As mentioned above,in most developing countries, existingsmall-scale bridges generally are
structurally weak and in poor condition.
These bridges may not withstandsevere weather conditions. As theintensity of storms is expected toincrease, these bridges are likely to be
exposed to higher risk of failing andcollapsing.

hurricanes and tropical storms, which
are expected to increase in intensity
and generate stronger storm surges
and waves. Both bridge scour anddirect physical impact can damage
bridges and cause them to collapse.
In addition, increased temperatures
can damage pavements that protect
the bridge decks, and damage theexpansion joints of bridges.

Small-scale bridges, once damaged,
can become unstable and dangerous
to use. When bridges are destroyed
and become inaccessible, rural
Wildfires May be a Hazard forcommunities may be isolated andBridges Made Out of Timber. The risk residents of those communities willof wildfires is likely to increase in areas be at risk due to isolation and inability
where reductions in average rainfall
to travel or purchase goods. Since
combine with increases in averagesmall-scale bridges are often built withtemperatures worsening the risk ofhigher levels of risk and the condition
drought and heatwaves.
is generally poor, extra measuresand considerations are needed toensure these bridges can safely and
SUMMARY OF IMPACTS TO
reliably provide essential access forcommunities and businesses. Table 2
BRIDGES
provides examples of potential climate
Large-scale bridges are mainly
impacts on large- and small-scaleaffected by scour resulting from more
severe flooding and direct impact from bridges.

CLIMATE IMPACTS AND RISKS

2.7
2.5

TABLE 2: BRIDGE INFRASTRUCTURE
Climate Drivers

Impacts and Consequent Risks

Large-scale Bridge Structures
Increased frequency of extreme precipitation events increases the risk for flooding, which can reduce theservice life of bridges by:
Increased frequency of extreme
precipitation events and floods• Increasing the scouring rate of bridge foundation or pier, and build-up of sediments• Increasing moisture levels in soil that may lead to loss of structural foundation integrity• Increased intensity of storms can place additional stresses on bridges

As sea level continues to rise, coastlines will change. Thus, infrastructure that was not previously at risk may
be exposed to storm surge and wave damage in the future. Storm surge is caused by strong storm winds
and pressures, which lead to increases in water levels. Both sea level rise and storm surges can:Sea level rise, storm surge andwaves• Damage bridges and connected roadways due to flooding, inundation, and erosion of land that
accommodates infrastructure• Decrease expected lifetime of bridges• Storm surges and waves can exceed more than several feet and can cause significant damage to thestructure of a bridge and connecting roadways• Result in scour by eroding riverbeds and exposing bridge foundations and piersHigher temperatures and extreme heat can cause:

Increase of extreme temperatureand heat waves• Bridges to be stressed by thermal expansion and movement• Premature deterioration of infrastructure• During winter periods, the greater daily variability and range of maximum and minimum temperature cangenerate more frequent freeze-thaw conditions which may damage bridge joints

Small-scale Bridge Structures

Increased frequency of extreme
precipitation events and floods

USAIDAFGHA N STANALP

Extreme heat and heatwaves,wildfires

2.8

CLIMATE IMPACTS AND RISKS

Similar to large-scale bridges, small-scale bridges, such as a pedestrian footbridge, can be damaged byflooding caused by an extreme precipitation event. However, small-scale bridges are more vulnerable
since they are often not designed to withstand powerful floods or strong winds. Therefore, an increase infrequency and intensity of storm events will pose a greater risk to small-scale bridges, as compared to largescale bridges

Small-scale bridges are less susceptible to changes in temperature (both extreme and gradual), than largescale bridges. They typically are short , made of local material and not built with expansion joints. Premature
deterioration of materials can result from prolonged periods of extreme heat
Wildfires may be a hazard for bridges made out of timber in areas impacted by heat waves and drought

CLIMATE IMPACTS AND RISKS

2.11

XX

CLIMATE IMPACTS AND RISKS

2.9

DeNatale, AECOM

XX

MozambiqueCHAPTER 3

A CLIMATE RESILIENTINFRASTRUCTURE
METHODOLOGYXX

ENABLING
CLIMATE RESILIENTPLANNING AND
DESIGN OF BRIDGEINFRASTRUCTURE

This chapter provides a step-wisemethodology to enable practitioners toinclude climate change considerationsin the design of new structures orthe evaluation of existing ones (seeFigure 2).
• STEP 1 establishes the context of
the assessment defining the asset
and the climate impacts that will be
the focus of the assessment.
• STEP 2 considers the vulnerability(exposure, sensitivity, and adaptive
capacity) of the assets screening
those that require more detailed
analysis.
• STEP 3 identifies, analyzes
and evaluates the subsequent
risks (combining likelihood withconsequences).
• STEP 4 develops adaptation
strategies to address the mostsignificant risks.
• STEP 5 guides the implementation,
monitoring and evaluation ofadaptation solutions.

In applying the methodology, themajority of the effort is focused on
Steps 3 and 4. Risk assessment andadaptation to climate change impacts
should be part of a multi-criteria
decision-making process (alongwith other technical, socio-cultural,environmental, economic, and financial
factors) that reviews solutions andoptions during engineering planningand design. While the capital costsof creating infrastructure assets thatare more resilient to climate change
impacts may guide the adaptation
strategy selection and design, a proactive approach when possible andaffordable is often more cost-effective
than being reactive. It will ultimately bemore economical to build stronger andbetter located assets than to rebuild or
repair structures following a disastrous
event, in addition to other costs suchas healthcare and clean-up that may
result from failure of an asset.
If a risk management process isalready in place for infrastructure
activities, the following framework canbe used to assess the adequacy or
identify gaps in the process. If there is
no existing risk management process
in place, this step-wise approach canbe used to establish such a process.

STEPWISE APPROACH
FOR CLIMATE RESILIENTINFRASTRUCTURE PLANNING
AND DESIGN
The management of climate changerisks in USAID infrastructure activities
can be facilitated by the following fivestep process including:

5 STEP PROCESS
1

Establishing the Context

2

Vulnerability Assessment

3

Risk Assessment

4

Development of Adaptation
Strategies

5

Implementation

Collectively, these steps establish aclimate resilient design methodology to
be used when determining appropriate
engineering design actions for moreclimate resilient structures.
This process will help establish
whether or not an existing or future
infrastructure asset is vulnerable andat risk from climate change impacts.
Tools, in the form of checklists,
worksheets, or matrices, can support
practitioners in undertaking these steps
and are provided in this chapter.

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGY

3.1

3.2

IDENTIFY CLIMATE IMPACTS

DEFINE ASSETSTEP 1

What are the expected changes innatural hazard and climate change
patterns for the region?

(e.g., reservoir, transmission line,
roadway, water treatment plant)

Establish
Context

EXPOSURE ANALYSISIs the asset exposed to the anticipatedclimate change impacts?

NO

Assessment complete,
no further action needed

YES
Low Sensitivity
or Not Sensitive

SENSITIVITY ANALYSISSTEP 2

Vulnerability
Assessment

To what degree is the asset affected,
either adversely or beneficially, by theclimate change impacts?

Assessment complete,
no further action needed

Highly or Moderately Sensitive
The Asset is Vulnerable to Climate
Change Impacts

Adaptive Capacity
Considerations

LIKELIHOOD ANALYSISCONSEQUENCE ANALYSIS

What is the probability of andconfidence in the occurrence of the
anticipated climate change impact?

STEP 3What are the economic, social, or
ecological outcomes associated withthe climate impact on the asset?
Insignificant,Minor, Moderate,
Major, orCatastrophic

RISK ANALYSIS

Rare, Unlikely,
Possible, Likely, orAlmost Certain

Combine likelihood and consequence
to rank the risk.

RISK EVALUATION

Risk
Assessment

Is the risk acceptable?

Extreme, High,or Medium Risk

Assessment complete,
no further action needed

Not Significant, or
Low Risk

The Risk Requires Development of an Adaptation Strategy

DEVELOPMENT & COMPARISON OF
ADAPTATION RESPONSES

How should engineering design be adjusted to account for climatechange impacts? What are the optimal (multi-criteria) responses?

STEP 4Adaptation
Strategy

PROJECT APPRAISALSTEP 5

Incorporate lessons learned in future
design and planning process

Further refine options (e.g.,cost benefit)

BEST PRACTICES

Implementation

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGY

Selection of the Appropriate
Adaptation Strategy

RESOURCE-BASE
ANALYSIS

Availability of and access toresources

MONITORING & EVALUATION
Monitor and evaluate for change
in risk status

COMMUNICATION AND CONSULTATION WITH TECHNICAL EXPERTS, IMPLEMENTING PARTNERS AND STAKEHOLDERSSTEPS IN THE METHODOLOGY FOR INCORPORATING CLIMATE ADAPTATION IN INFRASTRUCTURE PLANNING AND DESIGNXXFIGURE 2: USAID’S CLIMATE-RESILIENT DEVELOPMENT FRAMEWORKSTEP 1: ESTABLISHING THE CONTEXTIDENTIFY CLIMATE IMPACTS

DEFINE ASSETSTEP 1

What are the expected changes innatural hazard and climate change
patterns for the region?

(e.g., reservoir, transmission line,
roadway, water treatment plant)

Establish
Context

The first step in the overall approach is
to define the service to be delivered by
the infrastructure activity in the face of
future climate change. Establishing thecontext notably includes defining theservice to be delivered by the bridge
infrastructure within the context of
future climate change.

DEFINING
INFRASTRUCTUREOBJECTIVES

For bridge infrastructure, establishing
the context includes gathering researchand information to understand baseline
and projected traffic conditions, travel
patterns, and mode share usage(automobile, truck, bus, bicycle, andpedestrian). Understanding projected
use can assist in determining if any
changes to the target level of service
may be required. Climate change
can represent one of a number of
influences that may affect demand
for a particular service or asset, andpractitioners should therefore assess
the potential for changes in demand
as a result of climate change risks.
For example, coastal erosion or flood
events may cause a gradual shift in
population over time away from anarea at risk due to sea level rise, andanticipated travel patterns will change
accordingly.

Consideration should also be given to
the broader system that the assets areintegrated with. Once the scope of theassets is defined, information about theassets are needed to inform the laterstages of the assessment. Typicallyan inventory or database is developedthat contains information on each
asset’s criticality, function, condition,
location, design and interdependences.
This information may be sourced fromexisting asset management systems or
operational staff. Site visits or physicalsurveys may also support this task.

UNDERSTANDING AND
IDENTIFYING CLIMATEAND NON-CLIMATESTRESSORS

Gathering data and information via
research will also help practitioners
understand current hazards, how they
may be affected by climate change,
and identify relevant internal andexternal factors that are within or
outside the control of the project teamor organization.

(financial resources, economic
activities, culture and traditions,education, and socio-demographic
conditions); biophysical aspects(biodiversity, geomorphology,hydrology, and soils); and institutionalarrangements (governance,
regulations, and stakeholder
relationships among public, private,
and voluntary sectors).
Most of these factors will be reviewed
as part of typical planning infrastructuredevelopment activities. The additional
element that must be integrated
involves climate science modeling forthe region to understand what the likely
changes in climate variables such as
rainfall patterns, extreme temperature,or storm events might be. For coastal
projects, projected sea level rise andstorm surge must also be reviewed.

Internal factors include objectives
and criteria governing investment
decisions, engineering specifications,or service delivery targets. External
factors include socio-economic

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGY

3.3

XX
SOURCING CLIMATEDATAUSAID development projects areundertaken in a variety of geographic
settings and country contexts
involving floodplains, coastal atolls,
mountainous and arid regions. Whenevaluating climate impacts and risks
to infrastructure assets, understanding
the context by collecting climate dataand projected trends for specificgeographic locations will be a criticalfirst step. In many developing country
settings, detailed climate observations
and projections may be scattered,inaccurate, incomplete, or not

3.4

available. Lack of weather stations,difficulties in terrain, and inaccuracies
from data collection (i.e., humanerror) are all factors that can create
uncertainty. Practitioners can respondby making conservative estimates
based on available data and source
data at the regional and continental
scales.
In some situations, lack of specificclimate data may be overcome byconsulting available data in similarparts of the region, traditional
knowledge and mapping, drawing
from studies conducted under similar
conditions or by conducting new

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGY

studies. The USAID Overarching
Guide: A Methodology for Incorporating
Climate Change Adaptation in
Infrastructure Planning and Designcontains additional information andguidance on climate data and trends
as well as information sources that
may assist with this step.

STEP 2: VULNERABILITY ASSESSMENTEXPOSURE ANALYSISNOIs the asset exposed to the anticipatedclimate change impacts?

Assessment complete,
no further action needed

YES

SENSITIVITY ANALYSISSTEP 2

Vulnerability
Assessment

To what degree is the asset affected,
either adversely or beneficially, by theclimate change impacts?

Low Sensitivity
or Not Sensitive

Assessment complete,
no further action needed

Highly or Moderately Sensitive
Adaptive Capacity
Considerations

The Asset is Vulnerable to Climate
Change Impacts

CONDUCTING A
VULNERABILITYASSESSMENT

1. Analyze exposure of theasset to hazards using spatial
information
2. Analyze sensitivity of the asset
using a sensitivity matrix
3. Consider adaptive capacity

The second step in the overall
approach considers the degree
to which an infrastructure asset issusceptible when exposed to hazards
identifying those that warrant moredetailed investigation in Step 3.
The vulnerability screening involves
understanding an asset’s vulnerability
to specific climate change impacts overtime. Climate-Resilient Development:
A Framework for Understanding andAddressing Climate Change4 defines
vulnerability as a function of an asset’s
exposure, sensitivity and adaptive
capacity to a specific climate hazard.

DETERMINING ASSETEXPOSURE

Exposure is the nature and degree towhich a structure or asset is subject
to a climate impact. For example, abridge likely to be impacted by tidal
flooding as a result of sea level riseat mid- century would be exposed tothis climate impact, whereas a bridgethat is not likely to be impacted bytidal flooding would be considered not
exposed.
For each planned activity, determine
whether or not it is likely to be exposedto the impacts identified in Step 1.
Spatial information related to hazards
will assist this process (e.g. flood
hazard or other planning maps). Only
those assets deemed to be exposed
to particular climate change impacts
identified in Step 1 should progressto the assessment of sensitivity. If an
asset or project site is not exposed
to climate change impacts, then theassessment is complete at this point.

DETERMINING ASSETSENSITIVITY

Sensitivity is the degree to which asystem is affected, either adversely
or beneficially, by climate stressors.
For example, a wooden bridge may
be more sensitive to wildfire than aconcrete bridge due to the potential
damage that fire may cause to the

USAID. 2014. Climate-Resilient Development: A Framework for Understanding and Addressing Climate Change. Washington, D.C., available at http://www.usaid.gov/
climate/climate-resilient-development-framework.

4

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGY

3.5

wooden construction materials
compared to concrete construction
materials. Table 3 outlines the levels of
sensitivity ranging from Not Sensitive
to High Sensitivity. Using this scale,project elements that are rated ashaving a Moderate or High Sensitivity
would be deemed vulnerable to theclimate impacts associated with therelevant climate hazard and be thefocus of the risk assessment. To help
inform sensitivity assessments, Table
4 provides a summary of the likely
sensitivity of different types of bridge
infrastructure to different climate
hazards. Noting, that the sensitivityof a bridge will be dependent on
its construction materials, Table 5summarizes the sensitivity of different
materials to various climate variables
in temperate climates.

TABLE 3: LEVELS OF SENSITIVITY TO CLIMATE CHANGE IMPACTS
Level of
Sensitivity

Definition

NOT
Sensitive• No infrastructure service disruption or damage

LOW
Sensitivity• Localized infrastructure service disruption; no permanent damage• Some minor restoration work required

MODERATE
Sensitivity• Widespread infrastructure damage and service disruption requiring
moderate repairs• Partial damage to local infrastructure

HIGH
Sensitivity• Permanent or extensive damage requiring extensive repair

Moderate or high sensitivity impacts are considered vulnerable and should be
the focus of the risk assessment.

TABLE 4: LIKELY SENSITIVITY TO CLIMATE CHANGE IMPACTS

THEME

PROJECT
ExtremeHeat

DryingTrend/
DoughtExtremePrecipitation/
Flooding

Storm
Surge

Sea Level
Rise

Damaging
Storms(wind,
lightning,snow/ice)

Wildfire

Large-scale bridges

Bridges

Small-scale bridges

NOT Sensitive

LOW Sensitivity

MODERATE Sensitivity

HIGH Sensitivity

TABLE 5: DIFFERENTIAL IMPACT OF CLIMATE EFFECTS ON MATERIALS
Material

CarbonDioxideCyclones &StormsSea Level
Rise

ExtremeRainfall &FloodsAnnual &Max Temp

Ultraviolet
Radiation

Wildfire

Drought

Concrete

M

H

H

M

M

L

M

L-M

Metals

L

H

H

M

M

L

H

L

Mortar

L

M

M

M

L

L

M

H

Timber

L

M

M

M-H

M

L

E

L-M

Coatings

L

M

L

M

M

H

E

L

Polymers

L

M

L

L

M

H

E

L

*Tested on commonly used materials in engineering designs for temperate climates only (© AECOM – Climate sensitivity of materials research, S.E. Australia Region 2007)

L

3.6

Low

M

Moderate

H

High

H

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGY

ExtremeFollowing the determination of anasset as vulnerable, practitioners may
also consider the adaptive capacityof the infrastructure system. This
step is not critical to the vulnerability
screening process, however, it may
provide useful information to inform theconsequence discussion in Step 3.

Adaptive capacity is generally
considered as a social component
when working with soft infrastructure.
When working with built or hard
infrastructure, adaptive capacity refers
to the ability to anticipate, prepare andrecover from climate impacts.
From a system perspective, thismay be assessed by looking at coreeconomic drivers in-country (or insimilar contexts if not readily available),such as access to health services
and education, resource strength interms of wealth and human, strengthof networks, institutions leadership,and disaster response mechanisms.
Focusing on specific infrastructure,
consideration may be given to thepotential for supplementary capacity(e.g. redundancy), likely duration of a
disruption to service or the duration of
repairs to return an asset to operation.

Roadway and bridge software, suchas the Bentley MX Road software, canbe used to model and analyze all typesof structural components. Technology
such as this is helpful when determining
an asset’s operation and future function.
A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGYAECOM JAMSHEDPUR ROAD CORRIDORASSESSING ADAPTIVECAPACITY

3.7

XX
STEP
3: RISK ASSESSMENT
LIKELIHOOD ANALYSISCONSEQUENCE ANALYSIS

What is the probability of andconfidence in the occurrence of the
anticipated climate change impact?

STEP 3

Rare, Unlikely,
Possible, Likely, orAlmost Certain

What are the economic, social, or
ecological outcomes associated withthe climate impact on the asset?
Insignificant,Minor, Moderate,
Major, orCatastrophic

RISK ANALYSIS

Combine likelihood and consequence
to rank the risk.

RISK EVALUATION

Risk
Assessment

Is the risk acceptable?

Extreme, High,or Mediumn Risk

Not Significant, or
Low Risk

Assessment complete,
no further action needed

The Risk Requires Development of an Adaptation Strategy

CONDUCTING A RISKASSESSMENT

1. Define the likelihood of climate
impacts occurring

2. Understand the consequencesof climate impacts
3. Conduct a risk analysis anddevelop a risk rating matrix
4. Accept the appropriate level ofrisk and adaptation needs

The third step of the approach enables
practitioners to consider risks once thevulnerability of an asset or project has
been established. A risk assessment
provides an analytical framework withqualitative descriptors for likelihoodand consequences in a resulting risk
matrix. Only those assets that havebeen identified as vulnerable in Step 2
need to be analyzed for risk.

This approach is aligned withtraditional risk management
principles (e.g. ISO 31000:2009
Risk management—Principles andguidelines). Exposure and sensitivity
data gathered in Step 2 can be used
to inform the rating of likelihood andconsequences.

Risks are often expressed as the
combination of the consequences of anevent and the associated likelihood of
it occurring:
RISK = CONSEQUENCES x LIKELIHOOD

3.8

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGYLIKELIHOOD OF CLIMATEIMPACTSconsequences. There may be one or• Reputation. Loss of service, healthseveral criteria used, depending on
or environmental impacts may affectthe project. Examples of consequence
the reputation of the responsible
criteria which could be considered areagency.
listed below. Table 7 provides example
definitions for rating each consequence
criteria.
CONDUCTING A RISKTable 6 provides examples ofqualitative definitions that can beused to characterize the likelihoodof a risk occurring. The probability ofa risk occurring is often described inqualitative terms. Only when there is• Asset Damage. Damage requiring
sufficient data and capability can aminor restoration or repair may bequantitative description of likelihood beconsidered minor while permanentmade, where the time horizon is the life
damage or complete loss of anof the asset.
asset would be considered to be asignificantly higher consequence.
The level of certainty in determining the
likelihood of a climate impact largely• Financial Loss. A high repair or
depends on the scale and certainty
capital replacement cost would be ofthat the climate modeling exercise will
major consequence compared to ayield (e.g., more frequent heat waves),
cheaper repair or replacement cost.
changes in hydrological patterns (e.g.,recurring floods), variations in coastal
environments (e.g., sea level rise), and • Loss of Service. As an example,
a water system serving a largeclimate-driven gravitational hazards
scale industry with high water use(e.g., higher frequency of rock falls,
requirements would be of major
mudslides and avalanches).
regional consequence compared to
one serving a small-scale industry
Regional models will likely yield moreusing less water.
precise results with a smaller range of
projections, providing greater certainty.
• Health and Safety. A system
Assumptions regarding uncertainties
serving a large number of people
associated with the model, or awould be of major consequence
hypothesis when modeling is notcompared to a system serving a
possible, should be clearly articulated.
smaller number. Casualties or otheracute public health consequences
CONSEQUENCES OF
would weigh more heavily.

CLIMATE IMPACTS

It is important to understand theconsequences associated with anasset being impacted by a climate
hazard. Defining consequences isideally done in a workshop settingwith key stakeholders to identify
important criteria to be used to assess• Environmental Considerations.
Damage to a wastewater systemadjacent to a local drinking water
source, for example, would beof major polluting consequencecompared to a system isolated froma local water source.

ANALYSIS

Once the likelihood and consequence
are defined, the risk level is determinedby multiplying the likelihood value by
the consequences value to result in ascore from 1 (Low) to 25 (Extreme).
Generally, the resulting score will beassigned one of five levels of risk: Not
Significant, Low, Medium, High, orExtreme (Table 8).

DETERMINING RISKACCEPTABILITY AND THE
NEED FOR ADAPTATION

Based on the outcomes of the risk
analysis, it is necessary to determine
and prioritize those risks requiring
treatment with appropriate adaptation
measures. Risk acceptability criteria
need to be defined (refer to Table 9)
to guide the determination of whichrisks are determined to be acceptable
and the most significant risks requiring
treatment (i.e. adaptation planning).
Often the risk evaluation is led bya project funder or leader, rather
than the technical staff who leadthe risk analysis. Decisions on risktreatment should take into account theacceptability of external stakeholders
that are likely to be affected.

TABLE 6: EXAMPLE OF QUALITATIVE DEFINITIONS OF LIKELIHOOD
Level of Likelihood

Definition

5

Almost Certain

More likely than not, probability greater than 50%

4

LikelyAs likely as not, 50 / 50 chance3

PossibleLess likely than not but still appreciable, probability less than 50% but still quite high2

Unlikely

Unlikely but not negligible, probability low but noticeably greater than zero

1

Rare

Negligible, probability very low, close to zero

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XX
TABLE 7: EXAMPLE DESCRIPTOR FOR CONSEQUENCES
Level of Likelihood

Definition• Asset Damage: Permanent damage and / or loss of infrastructure.
• Loss of Service: Widespread and extended (several weeks) interruption of service of the agreed Levelof Service; result in extreme contractual penalties or contract breach.

5

Catastrophic• Financial Loss: Asset damage > annual maintenance budget or 75% of CAPEX value.
• Health / Safety: Substantial changes to the health and safety profile; risk of multiple fatalities as a resultof extreme events.
• Reputation: Irreversible damages to reputation at the national and even international level / Public
outrage.

• Asset Damage: Extensive infrastructure damage requiring extensive repair / Permanent loss of local
infrastructure services.
• Loss of Service: Widespread and extended (several days) interruption of service for less than 50% of
the agreed Level of Service; result in severe contractual penalties.

4

Major

• Financial Loss: Asset damage 50%+ of annual maintenance budget or 25% of CAPEX value.
• Health / Safety: Marked changes in the health and safety profile, risk of severe injuries and even fatality
as a result of extreme events.
• Reputation: Damage to reputation at national level; adverse national media coverage; Government
agency questions or enquiry; significant decrease in community support.

• Asset Damage: Damage recoverable by maintenance and minor repair / Partial loss of local
infrastructure.

3

Moderate• Loss of Service: Widespread interruption of service for less than 20% of the agreed Level of Service;
result in minor contractual penalties.
• Financial Loss: Asset damage > 10% but < 25% of annual maintenance budget or 5% of CAPEX value.
• Health / Safety: Noticeable changes to the health and safety profile, risk of severe injuries as a result of
extreme events.
• Reputation: Adverse news in media / Significant community reaction.

• Asset Damage: No permanent damage / Some minor restoration work required.
• Loss of Service: Localized interruption of service for less than 10% of the agreed Level of Service.

2

Minor

• Financial Loss: Asset damage > 5% but < 10% of annual maintenance budget or 1% of CAPEX value.
• Health / Safety: Slight changes to the health and safety profile; risk of minor injuries as a result of
extreme events.
• Reputation: Some adverse news in the local media / Some adverse reactions in the community.

• Asset Damage: No infrastructure damage.
• Loss of Service: Localized interruption of service for less than 1% of the agreed Level of Service (LoS).

1

Insignificant• Financial Loss: Asset damage < 5% of annual maintenance budget or negligible CAPEX value.
• Health / Safety: Negligible or no changes to the health and safety profile or fatalities as a result of
extreme events.
• Reputation: Some public awareness.

3.10

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGYTABLE 8: RISK RATING MATRIX

Likelihood Level

Level of
Risk

Consequence Level
Insignificant
(1)

Minor
(2)

Moderate
(3)

Major
(4)

Catastrophic(5)

AlmostCertain(5)

Medium (5)Medium (10)High (15)Extreme (20)Extreme (25)

Likely (4)Low (4)

Medium (8)High (12)High (16)Extreme (20)Possible(3)

Low (3)Medium (6)Medium (9)High (12)High (15)

Unlikely(2)

Low (2)Low (4)

Medium (6)Medium (8)Medium (10)Rare (1)Not
Significant (1)Low (2)Low (3)Low (4)

Medium (5)TABLE 9: EXAMPLE RESPONSES AND ACCEPTABILITY FOR
DIFFERENT LEVELS OF RISK
Level of Risk

Definition

EXTREME> 20• Extreme risks demand urgent attention at the most senior level andcannot be simply accepted as a part of routine operations• These risks are not acceptable without treatment

HIGH
12-16

• High risks are the most severe that can be accepted as a part of routine
operations without executive sanction, but they are the responsibilityof the most senior operational management and reported upon at theexecutive level• These risks are not acceptable without treatment

MEDIUM
5-10• Medium risks can be expected to form part of routine operations, butthey will be explicitly assigned to relevant managers for action, maintained
under review and reported upon at the senior management level• These risks are possibly acceptable without treatment

LOW<4• Low risks will be maintained under review, but it is expected that existing
controls will be sufficient and no further action will be required to treat
them unless they become more severe• These risks can be acceptable without treatment

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XX
STEP
4: DEVELOPING AN ADAPTATION STRATEGYDEVELOPMENT & COMPARISON OF
ADAPTATION RESPONSES

How should engineering design be adjusted to account for climatechange impacts? What are the optimal (multi-criteria) responses?

STEP 4Adaptation
Strategy

PROJECT APPRAISAL
Further refine options (e.g.,cost benefit)

DEVELOPING
AND SELECTING
AN ADAPTIONRESPONSE

1. Identify potential adaptation
solutions
2. Conduct project appraisal(e.g., CBA) to further refine
and generate a shortlist ofadaptation options
3. Consider the availability andaccess to resources, human andmaterial
4. Develop the adaptation strategy
with the identified adaptation
solutions

3.12

Selection of the Appropriate
Adaptation Strategy

Once the degree of vulnerability has
been established and the most criticalrisks have been identified, a decision
can be made regarding how to address
the risks. A range of appropriate
adaptation strategies are available
when preparing for and adapting toclimate change impacts. Selection ofa strategy is dependent on a numberof factors, including location, temporalscale, and the specific impacts faced.
Understanding the available resourcebase to implement the infrastructure
activity will also be important. Whilesome adaptation options may require
little resources (e.g., training ormonitoring) others may prove morecost-intensive.
Four generally accepted types ofadaptation responses that can be
implemented include: 1) accommodate
and maintain; 2) harden and protect;3) relocate; and 4) accept or abandon.
These strategies can help categorize
various adaptation responses for
new and existing infrastructure (Table10) and understand the various
advantages and disadvantages of
selected responses (Table 11).

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGYRESOURCE-BASE
ANALYSIS

Availability of and access toresources

Examples of adaptive engineering
design options specific to bridge
infrastructure are provided in Table 12,with additional detail provided in the
Annex.

SHORT-LISTING OF
ADAPTATION SOLUTIONS

Once a range of possible adaptation
options has been identified, theyshould be prioritized to create ashortlist of the most appropriate
options for implementation. A number
of approaches are available, including
decisions strictly based on best
judgment and not including detailed
analysis and justification. Common
approaches to shortlist options include
the use of a Multi-Criteria Analysis(MCA) or applying an economic
analysis, such as Cost-Benefit Analysis(CBA), to further refine and prepare
for implementation. An example ofa completed MCA is included in thecompanion document: Overarching
Guide: A Methodology for Incorporating
Climate Change Adaptation in
Infrastructure Planning and Design.

TABLE 10: APPROACH TO ADAPTATION STRATEGIESStrategic Approach

Adaptation Strategy
Existing Infrastructure

New Infrastructure1

Accommodate andMaintain• Extend, strengthen, repair or rehabilitate over time
• Adjust operation and maintenance• Design and build to allow for future upgrades,
extensions or regular repairs2Harden and Protect• Rehabilitate and reinforce• Add supportive or protective features• Incorporate redundancy• Use more resilient materials, construction methods,
or design standards• Design for greater capacity or service

3

Relocate• Relocate sensitive facilities or resources from directrisk• Site in area with no, or lower, risk from climatechange4

Accept or Abandon• Keep as is, accepting diminished level of service or
performance• Construct based on current climate, accepting
possibly diminished level of service or performance

TABLE 11: ADVANTAGES AND DISADVANTAGES OF ADAPTATION APPROACHESStrategic Approach

Advantages

Disadvantages

1

Accommodate andMaintain• Less costly• More pragmatic and flexible, allows adjustment
over time as more climate change data becomes
available• Requires monitoring, possibly frequent repairs,
adjustments, or more rigorous operations• Necessitates design for more flexible or
upgradeable structure2

Harden and Protect• Proactive• Straightforward to implement and justify• More costly• Assumes reasonably accurate climate forecasts

3

Relocate• Proactive• More costly• Sub-optimal location may decrease period of
performance or service

4

Accept or Abandon• No extra up-front cost

• Proper communications needed to inform
decision-makers and beneficiaries to expect lower
performance or service

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3.13

TABLE 12: EXAMPLES OF ENGINEERING ADAPTATION OPTIONS FOR CLIMATE RESILIENT BRIDGEINFRASTRUCTURE
Climate Drivers

Adaptation Measures
Adaptation strategies that address flooding and reduce its impacts on bridges fall under two broad categories:

Extreme Precipitation
Events, Flooding andDamaging Storms

Sea Level Rise and Storm
Surge• Protect bridges from damages caused by flooding by strengthening the bridge piers and foundations, or byincreasing the hydraulic capacity of the bridge by raising the bridge deck
• Minimize the occurrence of flooding or reduce its magnitude by increasing infiltration within the catchment
area draining through the bridge structure, or diverting high flows to drainage systems with a higher drainage
capacity• To protect bridges from powerful storm surges and waves, at-risk structures can be reinforced, particularly toprotect against scouring of bridge piers, columns, or foundations• Treat metal components of the bridge to resist corrosion due to increased exposure to salinity

Extreme heat and increases in diurnal temperature variation can damage expansion joints and deck surface
materials:

Extreme Heat, Heatwaves
and Wildfires

•
•
•
•
•

Replace or reconstruct bridge deck expansion joints to mitigate the impacts of higher temperature
Use paving materials that are more resistant to expansion in extreme heat conditions
Small-scale bridged built with timber are at risk of destruction in extreme heat causing wildfires
Build small-scale bridges with heat resistant materials or use coatings
Maintain and implement vegetation management practices that aim to minimize fire risk

ADB SOLOMON ISLANDS

Steel pedestrian bridge that will prove more
resilient to impacts from climate stressors
and their effects in the village of Maepua,
Makira in the Solomon Islands.

3.14

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGY

XX
STEP
5: IMPLEMENTATIONBEST PRACTICESSTEP 5

Implementation

Incorporate lessons learned in future
design processes

IMPLEMENTING THE
ACTIVITY

1. Provide on-going monitoring andevaluation to consider change inrisk status.
2. Identify and develop bestpractice examples to integrate
into future design processes.
3. Conduct consultation andtransparent communication
with all stakeholders involved
to promote buy-in and better
understanding of local context.

MONITORING & EVALUATION
Monitor and evaluate for change
in risk status

Implementation of climate change
adaptation programs may be definedsolely as an engineering program, butwill likely be part of a larger programthat includes planning and zoning,government and stakeholder buy-in,
and many other complex factors.

MONITORING AND
EVALUATION

Most projects and programs include
monitoring and evaluation activities
that can be adjusted to cover climatechange risks. If feasible, embedding
climate change risks in an existing
monitoring and evaluation frameworkis the preferred approach, rather thandeveloping a stand-alone climatechange risk monitoring and evaluation
framework.
Ongoing monitoring and evaluation
activities can help consistently adjust
the risk assessment and management
approach, and support developmentof risk treatments that are effective,
contribute to improvements in risk
understanding, detect changes inexternal and internal conditions, andidentify emerging risks.

Monitoring and evaluation should
be based on robust and simple tomeasure quantitative and qualitative
indicators. Careful consideration
should be given to the cost efficiency
and ease of measurement for the
proposed measures. Information canbe collected and analyzed through bothparticipatory and external evaluation.
Local communities can take a very
active role in monitoring tasks.

IMPLEMENTING BESTPRACTICES

Monitoring and evaluation provides
organizations with an opportunity toidentify assets susceptible to climatechange impacts and better informfuture asset planning. For example,
asset condition deterioration profiles
may change where assets are exposed
to more extreme conditions.
Climate change adaptation is an
emerging field, so implementation is
also experimentation in some cases.
Both successes and failures should bereported and documented to build acommunity of practice so that climatechange adaptation strategies improveover time and practitioners become
more conversant in implementing suchstrategies.

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3.15

COMMUNICATION AND
CONSULTATION

Climate change risk communication
activities should ideally form partof the overarching outreach andcommunications plan for each
infrastructure asset.
Communication and consultation
should ideally take place during allrisk management activities. A robust
and consistent communications
plan including consideration ofpotential climate change risks andselected adaptation options should
be developed in close collaboration
with implementing partners andstakeholders. A communication planshould outline how the findings of theanalysis will be made accessible tosupport decision making and generalawareness raising for both technicaland non-technical audiences.
Different target groups (e.g.,
government agencies, businesses,
communities, and women and children)and different communication vehicles

AECOM

Fiji Rd Improvement Project Community Meeting

3.22
3.16

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGY(e.g., workshops, reports, animations,summary sheets, and fact sheets)should be considered. Ongoing
communication and consultation
activities can support the developmentof appropriate objectives andunderstanding of the local context, help
ensure that climate risks are correctly
identified, and help build consensus
among stakeholders on the findingsof the risk assessment and the risktreatment selected for implementation.

XX

3.18

A CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGYA CLIMATE RESILIENT INFRASTRUCTURE METHODOLOGY

3.17

AUSTRALIAN EMBASSY VIETNAMXX

CLIMATE RESILIENT INFRASTRUCTURE DESIGN - CAO LANH BRIDGE,
VIETNAM

CASE STUDY

The information for this case study• Component 4 - Long Xuyen Bypass
has been drawn from that ADB Viet
(17.5 km);
Nam: Central Mekong Delta Region
Connectivity Project (Sovereign Project • Component 5 - Long Xuyen Bypass
extension (5.7 km); and| 40255-033) available at http://www.
adb.org/projects/40255-033/main.
• Component 6 - My An–Cao Lanh
The Vietnam Government hasconnecting road (26.9 km).
launched an expressway development
plan that identifies the Second
Climate change poses a challenge,
Southern Highway (SSH) as a key
worsening the risks associated withartery for development of the Mekong
large infrastructure projects within
Delta. The SSH connects Ho Chi Minh their lifespan. The Mekong Delta has
City through the Mekong Delta to thebeen identified as one of the world’s
southern coastal region and serves as most vulnerable regions to climate
an alternative to National Highway 1A. change. Predicted changes to theIt also provides access to the Mekong
climate of the delta could increase
Delta’s southwestern provinces, andboth the magnitude and frequency
connects to the Greater Mekong
of floods and storms and induce
Subregion Southern Coastal Corridor
greater seasonal variability in weather
at Rach Gia. The SSH is currently
patterns. This increases the risks to,interrupted by ferry crossings at Caoand potentially reduces the design
Lanh and Vam Cong, which are slow
life of, large infrastructure works. To
and cause delays to traffic.
mitigate such risk, climate proofing of
the infrastructure to be financed by the
The proposed plan by the government investment project is necessary.
was to remove the bottlenecks causedby slow ferry operations and, more
The Cao Lanh Bridge project is a
generally, improve connectivity inflagship investment worth US$150
the Mekong Delta by constructing
million, included technical assistancea section of the SSH between Cao
funds, and falls under Hanoi Post’s
Lanh (on the northern bank of theeconomic integration pillar. The
Tien branch of the Mekong River) andobjective of the Central Mekong Delta
Long Xuyen (on the southern bank ofConnectivity Project is to encourage
the Hau branch) (see Figure 3).This
the economic and social development
section will consist of:of the Cao Long Delta area.
• Component 1 - Cao Lanh Bridge(2.1 km) and approach roads (5.7km);
• Component 2 - Interconnecting road
(15.7 km);
• Component 3 - Vam Cong Bridge(2.9 km) and approach roads (2.9km);

The Cao Lanh Bridge project has beendeveloped with the support of the AsianDevelopment Bank (ADB) and theGovernment of Australia who financed
the Project Preparation Technical
Assistance (PPTA) grant. The purposeof the grant was to develop the project
to a level suitable for ADB financing.

PROJECTCOMPONENTS

There are three components to theCentral Mekong Delta Connectivity
Project:
1. The Cao Lanh bridge including theapproach bridges and the approachroad for a total length of 7.8km.
The Cao Lanh Bridge itself will bea cable stayed bridge with a central
span of 350m and a maximum
clearance above high water of
37.5m. Including the approachspans, the overall length of the CaoLanh Bridge is approximately 2km
and will be 6 lanes wide crossing abranch of the Tien River.
2. A connecting road between the CaoLanh and Vam Cong bridges will beapproximately 15.7km long and will
be designed to 6 lane expressway
standards but will be constructed
initially to 4 lanes.

3. The Vam Cong cable stayed bridge
The Cao Lanh Bridge is one of thewhich has a central span of 470m.
first large infrastructure investments toWith the approach structures theintegrate climate change in the region.
total length will be 2.9km.This
The objective of the Cao Lanh Bridge
is designated component 3A.
was to build resilience to climate-driven
Component 3B is the approach roaddisasters and damage, particularly
to the West of the bridge and isdownstream flooding and sea levelapproximately 2.9km long.
rise, and the focus was therefore
on technical specifications for risk
management.
CASE STUDY - 1

The Cao Lanh Bridge project generally
will be supported by soft ground,which will require special methods
to reduce settlements to acceptable
limits. The interface area between
bridges and culverts, which will besupported on concrete piles and thus
subject to minimal settlement, andthe adjacent highway embankments,
which will be subject to settlement overtime, will require special examination
to determine an economic methodof reducing the ‘step’ between
the embankments and bridges to
acceptable limits.
The impact of climate change on
the Mekong Delta is expected to besignificant and was taken into accountin the bridge and road design (seeTable 13).The hydraulic analysis took
into account:• Changes in peak water levels due tochanging fluvial flows and sea levelrise;• Changes in velocity;• Possible long-term
geomorphological impacts of sea
level rise on channel geometry andregime width; and• Possible impacts of climate change
adaptation measures, such as
raising of banks for protection.
The available guidance on expected
and extreme scenarios of climatechange for Vietnam and for regionalchanges in flow were used in themodeling and sensitivity tests carriedout. The regional model of the Mekong
delta was used so that changes atthe coast could be transferred to give
expected changes at the Cao Lanh
Bridge and road locations.
Climate change is projected to affectthe frequency and intensity of natural
disasters, and funding was contingent
on the incorporation of climate risk
projections in the bridge’s design. The
ADB, the coordinating development
partner for the project, funded
consultants to conduct a climate risk
study. The study found that increasing
the bridge’s design height by 0.75m
would strengthen its resilience up
to 20-year flooding events, and thisspecification was adopted by thebridge design team.
The climate change consultants to theproject also recommended that theassociated road network be raised

TABLE 13: CAO LANH BRIDGE
Carries

Motor vehicles, pedestrians and cyclists

Crosses

Tien River, Mekong Delta, Vietnam

Designer

Wilbur Smith Associates – WSP Finland - Yooshin Engineering
Corporation Joint Venture

DesignCable-stayed bridge with approach viaducts

Total length

650 meters (2,130 ft.)

Width

24.5 meters (80 ft.)

Height

120 meters (390 ft.)

Longest span

350 meters (1,150 ft.)

Number of spans

150 + 350 + 150 m (cable stayed parts)

Vertical clearance

37.5 meters (123 ft.)

Design life

100

Constructed by

Chinese Road and Bridge Corporation (CRBC) and the
Vinaconex E&C

Construction begin

2013

Construction end

Mid-2017

CASE STUDY - 2

by 0.6m, twice the Ministry of Natural
Resources and Environment’s ‘official’
climate scenario which projects a
sea level rise of 0.3m by 2050. An
incremental approach will immediately
raise the height of the road by 0.3m,
with plans to raise it by a total of 0.6m
over the course of the next decade as
the road is upgraded to an expressway.
The groundbreaking ceremony for the
Cao Lanh Bridge, held on 19 October
2013, was attended by senior officials
from the Vietnamese and AustralianGovernments and the ADB. The bridge
is expected to be completed after 43
months in mid-2017.

LESSONS LEARNEDThe following were the broad lessons
learned from project design andimplementation:• Include climate change
considerations in funding criteria;and• Having climate projections andrisk reduction recommendations
prior to the design phase helped toincrease buy-in from the Ministryof Transportation and other key
stakeholders, and strengthen theircapacities for understanding andmanaging uncertainties in climate
projections.
The Government of Viet Nam wascautious of the increased costs
resulting from climate proofing the
project. Raising the road could have
had cost implications for the wider
road network by potentially introducing
a new engineering standard, which
would affect other roads, both existingand planned. As loans replace grants
with Viet Nam’s transition to middle
income status, there are questions of
who will pay for the incremental costsof upgrading existing infrastructure to
be climate-resilient. This is a broader
issue that donors and governments
need to confront, but it also has
implications for expectations ofintegration in certain projects, and how
it is negotiated.

CASE STUDY - 3

SUGGESTED RESOURCES
General Resources for Bridge Design

Comité technique D.3 Ponts routiers / Technical Committee D.3. 2011. Road bridges, Adaptation to Climate Change for
Bridges, available at http://www.piarc.org/en/order-library/11607-en-Adaptation%20to%20climate%20change%20for%20
bridges.htm
Johnson, I. 2012. Adapting Vermont’s Transportation Infrastructure to the Future Impacts of Climate Change,
VTrans Climate Change Adaptation White paper,Vermont Agency of Transportation, August 2012, available at http://
vtransplanning.vermont.gov/sites/aot_policy/files/documents/planning/Climate%20Change%20Adaptation%20White%20
Paper.pdf
Khelifa, A., Garrow, L., Higgins, M., Meyer, M. 2011. The Impacts of Climate Change on Scour-Vulnerable Bridges: An
Assessment based on Hyrisk, Georgia Transportation Institute / University Transportation Center, October 2011, available
at http://ascelibrary.org/doi/abs/10.1061/(ASCE)IS.1943-555X.0000109
Research & Analysis Division. 2006. Adapting Infrastructure to Climate Change in Canada’s Cities and Communities – A
Literature review, Infrastructure Canada, December 2006, available at http://ipcc-wg2.gov/njlite_download.php?id=6305
Schwartz, H., Jr. 2010. Adaptation to the Impacts of Climate Change on Transportation, The Bridge – Linking Engineeringand Society Volume 40, Number 3, P.5 – P.13, National Academy of Engineering of the National Academies, Fall 2010,
available at https://www.nae.edu/Publications/Bridge/24514/24525.aspx
Suraje Dessai and Jeroen van der Sluijs. 2007. Uncertainty and Climate Change Adaptation - A Scoping Study,
Copernicus Institute, available at http://www.nusap.net/downloads/reports/ucca_scoping_study.pdf
The World Road Association (PIARC). 2011. Adaptation to Climate Change for Bridges – PIARC Technical Committee D3
Road bridges, August 2011, available at http://www.piarc.org
Warren, F. 2004. Climate Change Impacts and Adaptation: A Canadian Perspective, Natural Resources
Canada, available at http://www.nrcan.gc.ca/environment/resources/publications/impacts-adaptation/reports/
assessments/2004/10033

Detailed Information on Bridge Scour

Ameson, L., Zevenbergen, L., Lagasse, P., Clopper, P. 2012. Evaluating Scour at Bridges, U.S. Department ofTransportation – Federal Highway Administration, April 2012, available at http://www.fhwa.dot.gov/engineering/hydraulics/
pubs/hif12003.pdf
Wright L., et al. 2012. Estimated effects of climate change on flood vulnerability of U.S. bridges, Springer, February 2012.

RESOURCES - 1

RESOURCES - 2

XX

BRIDGE CLIMATE CHANGE ADAPTATION STRATEGIESANNEXINTRODUCTION

This Annex, Bridge Climate Change
Adaptation Strategies, is a companion
to Bridges: A Methodology for
Incorporating Climate Change
Adaptation in Infrastructure Planningand Design. More details, including
the advantages and disadvantagesof specific adaptation strategies, arediscussed in this document. Climatechange practitioners, engineers,and other stakeholders will find thecomponents to develop a preliminary
cost estimate that is valid for a
proposed project. Other aspects, suchas technical feasibility and schedule,
are also discussed in this Annex. It
is recommended that an in-depth
inspection and load rating analysis
be conducted for a bridge as part ofpreliminary design considerations.
Most international standards require
an engineer’s report for the basis ofdesign.
There are many comprehensive
solutions and adaptation options
that address climate change. Some
involve technology or innovative
design, while others involve the useof different materials. All options havetheir advantages and disadvantages,
for instance: concrete is less sensitive
to climate change effects, but harder
to maintain. Some adaptation options
may involve a substantial one-time,
capital expenditure (CAPEX), othersolutions require incremental increases
in normal business operational
expenditures (OPEX). Nonetheless, allstrategies are intended to assist withdecision-making for building bridges
that are climate-proofed. It is important
to note that schematic designs andgraphic illustrations should be preparedat the start of a project to convey theconcept or intervention to decision
makers and community stakeholders.

opportunities to incorporate climateproof designs into the repair andreconstruction activities.
Climate change adaptation is an
evolving field, with best practices
and as-built case study examples
being refined globally in multiple
environments and contexts. This Annex
is not intended to be exhaustive. If
there is a strategy or approach thatyou think merits more discussion inthis Annex, please send your ideas toclimateadapteddesign@usaid.gov. We
would like to consider user comments
and recommendations in our next
revision.

Not all adaptation strategies thatmake bridge structures more resilient
to climate can be applied to existing
infrastructure. Some solutions involve
modified design, such as raising theelevation of the structure, and cannot
be applied simply to existing bridges.
However, when a bridge is destroyed
after a major weather event or near
the end of its service life, it will be
important for practitioners to take

ANNEX - 1

CONTENTS
INFRASTRUCTURE DESIGN AND MATERIALS:.............................................................................................................. 3
MAKE GREATER USE OF CONCRETE......................................................................................................................... 3
REPLACE OR RECONSTRUCT BRIDGE EXPANSION JOINTS.................................................................................. 4
RAISE THE ELEVATION OF PROPOSED STRUCTURE TO AVOID FLOODING......................................................... 5
DEEPEN BRIDGE FOOTINGS TO PROTECT AGAINST THE EFFECTS OF CHANGES IN THE FLOW
OF RIVER....................................................................................................................................................................... 6
INFRASTRUCTURE PROTECTION AND DRAINAGE:...................................................................................................... 7
IMPROVE OR UPGRADE STORMWATER MANAGEMENT SYSTEM.......................................................................... 7
STABILIZE STREAM BANKS TO PREVENT EROSION AND TO PROTECT AGAINST BRIDGE SCOUR.................. 8
ADAPTATION OPTIONS TO PROTECT AGAINST SEA LEVEL RISE AND INCREASED INTENSITY,
DURATION AND FREQUENCY OF STORM SURGE.................................................................................................... 9
OPERATION AND MAINTENANCE:................................................................................................................................. 10
INCREASE FREQUENCY OF BRIDGE INSPECTION AND REPAIR.......................................................................... 10
POLICY AND PLANNING:................................................................................................................................................. 11
MORE STRINGENT WEIGHT RESTRICTION DURING FREEZE-THAW SEASON................................................... 11
TRAFFIC AND LOADING MANAGEMENT................................................................................................................... 12
DEVELOPMENT OF WATER SENSITIVE URBAN DESIGN (WSUD) GUIDELINES.................................................. 13
DEVELOPMENT OF A WSUD STRATEGY AND IMPLEMENTATION OF WSUD OPTIONS...................................... 14

ANNEX - 2

INFRASTRUCTURE DESIGN AND MATERIALSTABLE A.1: MAKE GREATER USE OF CONCRETE
Overview
Concrete is a commonly used construction material that has many benefits, which include the ability toresist high temperatures. Concrete is able to withstand extreme hot climatic condition, and generally
has the advantages of being durable and having a long service life. The rehabilitation of bridge deckpavement slabs should consider greater use of concrete and reinforced concrete depending on the
structural basis of the bridge.
Advantages• Ability to resist high temperature• Longer service life
• Require less maintenance and repair compared to asphalt, which results in lower operational cost

Disadvantages• More expensive than asphalt• Longer cure time than asphalt; De-icing in winter time should be done with non-chloride products
for the first year of service

Indicative Costs• Purchase of concrete pavement material, include aggregates and binders

Timing for Implementation• Immediately for new project; no additional time added to construction schedule• Few days depending on complete closure of bridge or partial closure

Governance• No specific governance requirements

Acceptability• HighFeasibility and TechnicalRequirement• To produce a correct concrete pavement mixture, knowledge of concrete design is needed. A
trained engineer is preferred to assess the bridge condition and ability to use concrete materials.

ANNEX - 3

XX
TABLE A.2: REPLACE OR RECONSTRUCT BRIDGE EXPANSION JOINTS
Overview
This method is primarily designed for existing structures. Bridge expansion joints can be damaged asa result of prolonged and extreme daily temperature variation occurs. There are several joint types
used in bridges that are part of the bridge and foundation design.
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Armor Joint (AJ);
Sealed Expansion Joints (SEJ);
Fabric Joint Underseal;
Header Type Joint;
Asphalt Plug;
Finger Joint; andModular Joint.

Bridge expansion joints allow thermal expansion and contraction, translation and rotation of the deck.
They also assist in keeping water off of the substructure and protect exposed concrete edges. During
extreme conditions, such as extreme hot days, expansion joints prevent bridges from bending out ofplace and allow enough vertical movement to permit bearing replacement.
Stresses on bridge expansion joints can be exacerbated by fatigue from heavy loading by vehicles
and increased frequency of extreme weather conditions. Their failure could cause damage to a bridge
substructure and superstructure.
Advantages

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•

Prevent more severe damages in the future
Further protect against extreme weather conditions
Preserve the expected life of bridges
Reduce the need for emergency repairs

Disadvantages• Traffic disruption since repair requires full or partial closure

Indicative Costs• Cost for construction workers and material for expansion joint

Timing for Implementation • Depends on type of structure, age and length – shorter if bridge is under complete closure
Governance• Approval from relevant planning authority

Acceptability• HighFeasibility and TechnicalRequirement• Trained worker to ensure replacement work is done properly and performed in accordance withprevailing bridge design guidelines

CASE STUDY - 4

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TABLE A.3: RAISE THE ELEVATION OF PROPOSED STRUCTURE TO AVOID FLOODING
Overview
An option to protect bridges is to increase the elevation of the structure by raising it to protect against
flooding and accommodate changes in higher tides and storm surges, associated with sea level rise.
This strategy allows roads to be built and located in vulnerable and exposure areas, with a low risk offlooding or susceptible to mud flow, geological collapse, or foundation deterioration.
Since the design of most structures utilizes historical climatic data, including documented peak flows,
the new design elevation should be above the historical peak and projected future high water level tooffset the alteration brought by changes in precipitation.
If raising the structure and associated approach roadways is feasible, this option can be effective inprotecting against flooding.
Advantages• A protective measure against increased frequency of flooding, mud slides, or physical deteriorationof bridge structural systems due to climate or severe weather• Allow infrastructure to be built on low-lying or vulnerable areas

Disadvantages• Raising the elevation of the structure can pose a design challenge to engineers• Notable increase in CAPEX; substantial amount of material needed to raise the structure

Indicative Costs• Cost of additional building material

Timing for Implementation• Planning and design time required. Actual construction time needed should be similar to typicalbridge projects

Governance• Government should be involved in the decision-making process• Consultation with government needed if adjustments involve increase in cost

Acceptability• Highly acceptable as this strategy will mitigate future damages

Feasibility and TechnicalRequirement• Requires project engineer to consider the alternatives, technical feasibility and consequence ofraising the structure

ANNEX - 5

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TABLE A.4: DEEPEN BRIDGE FOOTINGS TO PROTECT AGAINST THE EFFECTS OF CHANGES IN
THE FLOW OF RIVER
Overview
The flow of water can turn from slow to rapid in a short amount of time that can exert a strong force ona bridge foundation. A stronger foundation can protect a bridge from collapse due to the effects of thestronger flows associated with extreme precipitation events.
For new bridge projects, engineers can deepen the bridge footings – the enlarged portions of bridgefoundations that rest directly on soil, bedrock, or piles – to protect against the effects of changes in theflow of rivers. Designing and constructing deeper bridge footings can provide a stronger, more resilient
foundation.
Advantages• A protective measure against unanticipated changes in the flow of rivers• Protect a bridge from collapsing due to incapability of withstanding unexpected force – resulting in
potential savings due to avoided damages

Disadvantages• May encounter design challenges if geological conditions are complex• Higher CAPEX that often involves all elements of a bridge (e.g. deck, foundation, approachroadway, and utilities)

Indicative Costs• Cost of additional material

Timing for Implementation • Could be incorporated into design immediately
Governance• Consultation with government needed if adjustments involve increase in cost

Acceptability• Moderate to High acceptability. CAPEX can be commensurate with the bridge type, location, andlengthFeasibility and TechnicalRequirement• Needs to be re-designed according to professional bridge guidelines and standards, and by alicensed engineer• Alteration of the roadway connecting to the bridge may be needed as well as relocation of utilities
that are often affixed to the bridge deck

CASE STUDY - 6

XX
INFRASTRUCTURE
PROTECTION AND DRAINAGE
TABLE A.5: IMPROVE OR UPGRADE STORMWATER MANAGEMENT SYSTEM
Overview
Increased frequency and duration of intense precipitation events creates a greater amount ofstormwater runoff coming in contact with the different components of a bridge structure, thereby
creating conditions for deterioration and instability. Insufficient capacity of the drainage system
can cause water to remain either on or within the bridge structure. Damage may be minimized by
improving or upgrading the stormwater drainage system in the catchment draining through the bridge
structure to increase water infiltration and reduce excess runoff. Improvements to bridge-related
stormwater management also can reduce bridge deck runoff pollutants that flow into a receiving riverand landscape.
Advantages• Can be integrated into existing bridge system

Disadvantages• Increase in both the CAPEX and OPEX due to costs associated with assessment, prioritization,
design, and installation of retrofit opportunities for stormwater system, bridge deck drainage, andthe conveyance network• Need careful planning and may not be suitable in all locations• Maintenance is required and necessary in maintaining proper drainage

Indicative Costs• One-time capital and installation costs• Recurring maintenance costs

Timing for Implementation• Installation of bridge deck drainage retrofit or other stormwater management improvement over 3 to
6 months

Governance• Consultation with government entities to discuss funding for required CAPEX and OPEX

Acceptability• Moderate acceptability from government for relatively high cost projects• High acceptability from public as stormwater management systems generally cause limited
disturbance and provide benefits beyond increasing the resilience of a bridge

Feasibility and TechnicalRequirement• Engineers and stormwater specialists to design stormwater management for the deck surface
runoff• Skilled labor to perform maintenance

ANNEX - 7

TABLE A.6: STABILIZE STREAM BANKS TO PREVENT EROSION AND TO PROTECT AGAINSTBRIDGE SCOUR
Overview
Bridges that are located near stream banks or traverse across streams or waterways are exposed tosevere erosion that can deteriorate foundations and eventually damage a bridge. Extreme weather
events can cause erosion to occur more frequently as they can generate flash floods.
Stabilized stream banks can prevent erosion and protect against bridge scour. Bridge scour is oneof the main causes of bridge failure and collapses; protecting bridges against scour is very importantwhen evaluating adaptation options. Protection against bridge scour and stabilization of stream banks
can be done by installing revetments, gabions, riprap or other measures such as an increase invegetation.
Advantages• Could be implemented in the near-term as a generally cost-effective and efficient measure• Stream bank stabilization can have numerous positive impacts on the environment• Minimizing erosion can indirectly reduce the risk of flooding

Disadvantages• Some level of maintenance needed to ensure objects installed (culvert, gabion, etc.) are notdamaged after rainstorms and are maintained in good working order

Indicative Costs• Cost of material, landscaping and professional design services

Timing for Implementation • Immediately
Governance• Coordination with local government to perform banks stabilization and determine maintenance plan

Acceptability• HighFeasibility and TechnicalRequirement• Technical expertise required to asses and incorporate stabilization techniques

CASE STUDY - 8

XX
TABLE A.7: ADAPTATION OPTIONS TO PROTECT AGAINST SEA LEVEL RISE AND INCREASEDINTENSITY, DURATION AND FREQUENCY OF STORM SURGE
Overview
Sea level rise along with combined threats from strong storm surges pose a great risk to coastal
bridges. Several measures should be considered and used individually, or in combination, on future
bridge projects to protect against these climate stressors. Decision-makers can integrate numerous
adaptive measures into the new bridge design to increase the structure’s resilience. A sample list ofmeasures include:• Open-faced railings – to reduce wave forces and distribute water flow on a bridge deck. Railings
need to adhere to testing and crash-worthiness standards;• Raising piers – to elevate the structure above historic and future peak wave height and waterlevels. Ideally, a new structure should be constructed above historic and future peak levels;
however, depending on the bridge structure and its footing design along with other components likelocation and expected life of the bridge, the new elevation can vary and feasibility challenges may
prohibit implementation;• Lengthening piles – depending on the bridge type and compressive loads on a bridge, toaccommodate large anticipated wave loads, longer columns can be used and driven deeper into
the soil and bedrock, in order to provide a stronger support to the structure;• Use more rigid connections made of formed concrete to prevent decks from floating off bridge piers
when strong storm surges and waves exert extreme force on bridge decks; and• Site-specific protective structural or soft armoring measures applied around the base of a bridge
including scour apron or blanket.
The design for these types of protective measures can be challenging and very costly. Decision
makers need to consider the quantity of traffic utilization, scale, expected service life of the structure,and cost-effectiveness before applying these protective measures.

Advantages• If installed, these protective measures can be very effective in building resilience against storm
surge, wave and water forces• If elevated above historical peak or future heights, bridges could operate during extreme eventsand provide a safe evacuation route• Possibly reducing or avoiding costs to implement future remediation• Longer service life for bridges compared to those without protective measures

Disadvantages• Significant increase in CAPEX – variable depending on whether one or more type of measure isselected

Indicative Costs• High upfront cost, specific cost will be dependent on the type of protective measure implemented
and design factors

Timing for Implementation• The time-frame varies depending on the type of protective measure implemented and design
factors

Governance• Public and private consultation regarding funding for large-scale projects

Acceptability• Moderate acceptability – cost of some types of these structures may be too highFeasibility and TechnicalRequirement• A high level of technical expertise in multiple disciplines is generally needed, and varies dependingon type and scale of structure

ANNEX - 9

OPERATION AND MAINTENANCE
TABLE A.8: INCREASE FREQUENCY OF BRIDGE INSPECTION AND REPAIR
Overview
Increased frequency of bridge inspection and repair is another possible adaptation option. While somedamages caused by climate stressors can cause bridges to collapse, other damages are minor innature and would not pose an immediate threat to the structure or safety of travelers, but could build
up over time and ultimately result in bridge failure.
Conducting bridge inspections and repairs more frequently can ensure that incremental damages do
not worsen and are repaired before causing substantial damages to the bridge.
Advantages

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Prevent minor damages from becoming severe
Protect against extreme weather conditions
Preserve the expected life of bridges
Eliminate the need for emergency repairs

Disadvantages• Disruption to traffic during inspection and repair; disturbance to traffic can be minimized byscheduling maintenance at low traffic hours or weekends• Higher OPEX – need additional workers to conduct inspections

Indicative Costs• Minor increase in operational costs

Timing for Implementation • Immediately
Governance• Coordinate with planning authority to discuss inspection and maintenance plan

Acceptability• HighFeasibility and TechnicalRequirement• Requires experienced workers to inspect and identify damages

CASE STUDY - 10

XX
POLICYAND PLANNING
TABLE A.9: MORE STRINGENT WEIGHT RESTRICTION DURING FREEZE-THAW SEASON
Overview
Some bridge failures are due to fatigue from heavy loading during the freeze-thaw season. Averagetemperatures are expected to rise, thus temperatures in the winter will be warmer than in the past.
Applying more stringent weight restrictions could prevent fatigue and protect bridges when they arevulnerable and also when approach roads leading to the bridge are weakest.
Advantages• Reduce bridge fatigue and stress on material and joints• Preserve the expected life of bridges and maintain a state of good repair• Eliminate the need for emergency repairs

Disadvantages• Traffic disruption to truck vehicles in particular that have a defined route to distribute goods tomarkets• An alternate or detour route may not be available or be a viable substitute

Indicative Costs• Policy related costs• May add costs associated with increased mileage for bridge users

Timing for Implementation • Immediately
Governance• Coordination with local government to establish weight restriction (if not already existing) anddiscuss how to enforce the restriction

Acceptability• High to medium acceptability – restriction may receive disapproval by some bridge users

Feasibility and TechnicalRequirement• May require bridge engineer to determine what the acceptable weight load is for the bridge

ANNEX - 11

XX
TABLE A.10:TRAFFIC AND LOADING MANAGEMENT
Overview
Regardless the type of adaptation strategy selected to improve the resiliency of a bridge to climatechange, it needs to be accompanied by traffic (multi-modal and pedestrian in some cases) and truck
load management. Climate change is likely to intensify severe storms, storm surges and intense
precipitation, and require more frequent emergency response from transportation officials. Therefore,transportation and traffic officials should take a pro-active approach in dealing with climate extremes,
for instance:• Mapping, rating and prioritization of vulnerable travel routes, such as those that are becoming more
susceptible to flooding that is combined with route statistics (usage, infrastructure type, access totravel markets, etc.);• Establish emergency plan in coordination with other jurisdictions to divert traffic to alternativeroutes when primary route becomes inaccessible due to climate-related events, safety or security
concerns; and• Create and maintain an emergency operation budget that can immediately be used for emergency
response purposes.
Having emergency response plans established before a disaster occurs can improve thepreparedness of officials to deal with the impacts of such climate extremes.
In addition, traffic management policies can be applied to further protect bridges from damage fromclimate extremes, including:• Apply a loading restriction, that manages the incidence of heavy traffic traveling on a bridge
structure during the time of a day when bridge usage is the highest. This action can reduce bridge
fatigue and maintain expected service life of bridges; and• Increase frequency of temporary road closure to perform maintenance on road and repair minor
damages before damages worsen the condition of the bridge.
Advantages• Low CAPEX• Further protects bridges and its users

Disadvantages• Requires broad government coordination across sectors and levels

Indicative Costs• Policy an administrative costs

Timing for Implementation • Immediately
Governance• Commune, provincial and national government coordination and input

Acceptability• High acceptability where government communication is good
• Does not require tangible outcomes or impacts upon communities

Feasibility and TechnicalRequirement

CASE STUDY - 12

• Knowledge in emergency planning and response needed

XX
TABLE A.11: DEVELOPMENT OF WATER SENSITIVE URBAN DESIGN (WSUD) GUIDELINES
Overview
WSUD guidelines typically address issues around water supply and demand management with astrong focus on green infrastructure, while also considering the risks associated with non-potablewater sources. The guidelines would include sections to guide practitioners on green infrastructure
benefits, alternative water sources, risk management, site analysis and water balance assessmentand end use and treatment required. More detailed information would be developed for specific green
infrastructure elements such as rainwater tanks, stormwater biofiltration and constructed wetlands.
The guidelines would not provide detailed technical information but, rather, a general descriptionof the key WSUD fundamentals. The guidelines would be a relatively short document with a strongemphasis on graphic display of the information and easy to understand principles. The guidelines
would represent the cheapest and easier to implement options from a WSUD perspective.
The benefits from an improved water management perspective would be more limited than thedevelopment of WSUD strategy.

Advantages

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Enhances the current level of understanding of WSUD
Provides a framework for consistent implementation and integration of WSUD in new developments
Provides design guidance on WSUD details
Identifies issues that should be considered when evaluating strategies to achieve WSUD
Supplements (but not replaces) existing WSUD regulations and detailed design andimplementation guidelines• Directs readers to more detailed technical WSUD literature on specific issues and for location
specific advice

Disadvantages• WSUD guidelines would be more limited than a WSUD strategy due to their general nature• Do not take site specific conditions into account, including topography, soils, landscape, services
and other relevant site features and structural elements• Not a stand-alone design resource

Indicative Costs• The cost of developing WSUD guidelines would be minimal as it would not involve any specificinvestigations or site-specific details

Timing for Implementation • The development of WSUD guidelines can be achieved in weeks to months
Governance• WSUD is mandatory for certain scales and types of developments• WSUD would require involvement from relevant water utilities and their engineering divisions (orexternal procurement)• Stakeholder consultation is key

Acceptability• High acceptability – usually WSUD does not result in significant disturbance to local communities• Little public opposition against, and considerable support for, the use of WSUD
• Some aversion to new technology

Feasibility and TechnicalRequirement• Some WSUD technologies are simple to install and operate. Local people can be easily trained andconstruction materials are usually readily available• Primarily requires common engineering practices; however, some specific engineering inputs are
required for design and construction as well as for specific materials that may not be local• Existing local skills associated with current facilities can be used for operational purposes• May require advanced plumbing work

ANNEX - 13

TABLE A.12: DEVELOPMENT OF A WSUD STRATEGY AND IMPLEMENTATION OF WSUDOPTIONS
Overview
A detailed site analysis and water balance assessment would be the first step of a WSUD strategy.
The following site characteristics should be considered as part of a detailed site analysis:
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Climate (rainfall - annual average, seasonal variation);
Topography (steep slopes, vicinity to natural waterways);Soils and geology (suitability for infiltration);
Groundwater (depth to water table);
Salinity (acid sulphate soils);
Space (potential areas for water treatment and storage);
Services (conflicts with existing and proposed);
Environmental (significant species); andHeritage (retrofitting plumbing on heritage listed buildings).

Secondly, an assessment of the end use and treatment required should include at least a generalwater breakdown in terms of internal water use (e.g., drinking, showers, toilets and laundry), external
water use (e.g., irrigation, industrial plant, cooling towers), and an assessment of the suitabilityof alternative water sources (rainwater, stormwater, groundwater and recycled water). Finally thestrategy should determine the right balance of green infrastructure to be implemented to ensure thelong term efficiency of the WSUD measures.
Advantages• A WSUD strategy allows for the integration of all WSUD elements within the development• A WSUD strategy would be site and development specific as each site has specific environmental
conditions that influence implementation of WSUD, such as rainfall, topography, soils, creeks andreceiving waters

Disadvantages• WSUD upgrade requirements will vary between households and developments, increasing projectcomplexity• WSUD will only have an effect with widespread uptake

Indicative Costs• The cost of developing a WSUD strategy and implementation of WSUD options would vary on asite by site basis

Timing for Implementation• The development of a WSUD strategy and implementation of WSUD options can be achieved inmonths to years, depending on site specific details and requirements

Governance• WSUD is mandatory for certain scales and types of developments• WSUD would require involvement from relevant water utilities and their engineering divisions (orexternal procurement if they don’t have internal capacity), participation of the general community is
not required• Stakeholder consultation is key

Acceptability• High acceptability – usually WSUD does not result in significant disturbance to local communities• Little public opposition against, and considerable support for, the use of WSUD
• Some aversion to new technology

Feasibility and TechnicalRequirement• Some WSUD technologies are simple to install and operate. Local people can be easily trained to
implement such technologies, and construction materials are usually readily available• Primarily requires common engineering practices however, some specific engineering inputs are
required for design and construction as well as relevant materials that may not be local• Existing local skills can be used for operational purposes• May require advanced plumbing work

CASE STUDY - 14

XX

CASE STUDY - 16

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