Download Climate Change Risk Assessment

Climate Change
Risk Assessment
2015
vicroads.vic.gov.au
Disclaimer
This Assessment document has been prepared by VicRoads to assist it in adapting to climate change in the construction,
maintenance and management of road and road related assets. While it has been prepared taking all professional care, it should
not be relied on as the basis of decision making, but could contribute to the strategic context to inform further work.
Contents
Executive Summary
4
1. Introduction
5
2. Climate Change Adaptation
6
3. Strategic Context
8
4. Climate Change Projections
11
5. Climate Change Risk Assessment
14
5.1 Asset information
6. Detailed Risk Assessment
17
20
6.1 Sea Level Risk
20
6.2 Temperature
24
6.3 Rainfall
25
6.4 Extreme Weather Events
28
6.5 UV Level
29
6.6 Prioritising Risks
30
7. Developing Adaptation Responses
32
7.1 Sea Level Rise
32
7.2 Temperature
34
7.3 Rainfall
35
7.4 UV Level
36
7.5 Long Term Asset Responses
36
7.6 Organisational Responses
37
8. Next Steps
38
Glossary39
Bibliography40
Appendices42
Appendix 1 : Case Studies
42
Phillip Island Road – Climate Adaptation
42
Great Ocean Road – Adaptation Measure
43
Executive Summary
Similar to other road agencies both nationally and
internationally, VicRoads is working to develop
its own responses to climate change. Significant
effort has been undertaken in the last five years
to understand the level of risks posed to the road
network from the projected changes in climate and
to take action to mitigate its greenhouse emissions
to lessen the impacts and the risks associated with
climate change (VicRoads, 2010).
In general the more mitigation there is, the less
will be the impacts to which we will have to adjust
and the less the risks for which we will have to try
and prepare. Conversely, the greater the degree of
preparatory adaptation, the less may be the impacts
associated with any given degree of climate change.
This risk assessment document summarises the
work undertaken to assess the risks to VicRoads
infrastructure associated with climate change
parameters, as well as some appreciation of the
timeframe and potential directions for climate change
adaptation. In developing this Assessment document,
VicRoads has assumed a future climate with the
highest level of climate change impact, consistent
with the approach of most organisations and
government bodies within Australia.
4
Overall, the climate change risk assessment has
identified that whilst there are forecast impacts to
different asset classes through time, the appropriate
approach is primarily guided by the likely lifespan
of the assets. For example, with respect to assets
with short life spans (i.e. Intelligent Transport
Systems), or periodic replacement requirements
(i.e. pavement surfacing) adaptation measures
will be implemented as a running change at an
appropriate point in time. However, a number of
assets have a lifetime beyond normal budgetary
forecasting timeframes (i.e. bridges). In these cases,
the adaptation measures will need to be built into
the construction requirements of future assets
and a set of responses will be needed to manage
existing assets to ensure they continue to perform
for their planned life.
The greatest single climate change risk to VicRoads
is the impact to assets in coastal regions from sea
level rise. Whilst these impacts are predicted in low
lying areas across the entire Victorian coastline,
the impact is likely to be greatest in Eastern
Region, potentially through a combination of the
overtopping of roads, impacts to pavement layers
and the structures of bridges in these locations
resulting in likely interruptions to network operations.
Whilst it is important to start building knowledge
in the shorter term to support adaptation actions,
sufficient time remains to be better informed as new
information emerges regarding climate projections.
As a consequence, this adaptation strategy will
need to continuously evolve as more modelling
and measurement is undertaken to monitor the
performance of the road network over time. This
is particularly important as data regarding the
performance of the road network or changes to
climate projections will be analysed and absorbed
often faster than policy and planning can adapt.
1. Introduction
The VicRoads road network is a $45 billion
government asset, a key component of the state’s
overall transportation infrastructure, which links
with local roads and other transportation modes.
Its continued safe and efficient operation is
essential to economic prosperity.
VicRoads operates, maintains and upgrades the
main and arterial road network, which consists of
over 22,500 kilometres (51,500 lane kilometres) of
main roads across the state. Approximately 19,100
kilometres are located in regional Victoria, the
remainder in Metropolitan areas. Many of VicRoads
activities are either directly affected or influenced
by the weather and climate. Along with other state
and national infrastructures, roads are vulnerable to
the effects of climate change.
Many of the projected impacts will be adverse,
but some may be positive. This Assessment
document outlines how VicRoads will address
adaptation in response to the potential impacts
of climate change during the planning, design,
operation and maintenance of the State’s main
road infrastructure. In particular, it addresses
how VicRoads will factor in anticipated changes
in climatic parameters into the delivery of its
activities and develop appropriate management
and mitigation solutions to remove or reduce
these risks.
The magnitude and rate of climate change
depends partly on future global greenhouse
emissions. Consequently, mitigation action to
reduce greenhouse gas emissions has been and
continues to be a key focus of other strategies.
However, even if global greenhouse gas emissions
were to stop today, climate change would
continue for many decades as a result of past
emissions and the inertia of the climate system.
Adaptation to already experienced changes in
climate as well as to plausible future climate
scenarios is therefore a necessity.
CLIMATE CHANGE RISK ASSESSMENT
5
2. Climate Change Adaptation
There is increasing scientific consensus that the
global climate is changing, with these changes
being observed and increasingly documented
across the world (Stocker, et al., 2013), across
Australia (CSIRO, 2014), across Victoria
(Commissioner for Environmental Sustainability
Victoria, 2012) and locally within Victoria (SKM,
2012). These changes are relative to historical
trends and are being observed in a number of
climate parameters such as rainfall volumes and
patterns, temperatures as well as sea levels. Whilst
most parameters are currently operating within
historical ranges, they are forecast to move beyond
these by the end of the current century.
A number of organisations have sought to define
the concept of adaptation. For the purposes of
this Assessment document, adaptation consists
of actions that reduce the vulnerability of natural
and human systems or to increase system
resiliency in light of expected climate change
or extreme weather events. Climate change
adaptation for VicRoads is concerned with
maintaining network and asset performance
within this changing climate. Several aspects
of this definition merit attention.
First, the types of actions that can be taken to reduce
vulnerability to changing environmental conditions
include avoiding, withstanding, and/or taking
advantage of climate variability and impacts. Thus,
for roads and other road related facilities, avoiding
areas forecast to have a higher risk of significant
climate impacts should be an important factor in
planning decisions. If such locations cannot be
avoided, steps need to be taken to ensure that road
infrastructure can withstand the projected changes
in environmental conditions. For example, the
potential for increased flooding might be a reason to
increase bridge elevations beyond what historic data
might suggest. Climate change may also present
opportunities that transportation professionals can
take advantage of, like the placement of bituminous
surfacing during spring and autumn at some
locations. These types of actions decrease the
likelihood of impacts occurring.
6
Second, the result of adaptive action either
decreases a system’s vulnerability to changed
conditions or increases its resilience to negative
impacts. For example, increasing ultra-violet
radiation exposure can cause bituminous surfaces
across the road network to fail sooner than
anticipated. Using different materials or different
approaches that recognize this vulnerability can
lead to surfaces pavement that will not suffer
adverse performance with higher radiation levels.
Operational improvements could be made to
enhance detour routes around flood-prone areas as
a form of resilience. Another example of resilience
is the development of well-designed emergency
response plans, which can increase resilience by
quickly providing information and travel alternatives
when highway facilities are closed and by
facilitating rapid restoration of damaged facilities.
By increasing system resilience, even though a
particular facility might be disrupted, the main road
network as a whole still functions and decreases
the consequences of impacts.
Figure 2.1 illustrates the different approaches to
adaptation. Some adaptation strategies could be
targeted to reduce the impacts of specific types
of climate changes. For example, by protecting
existing assets or by relocating assets away from
vulnerable areas, the functionality of that asset
is preserved in future years when more extreme
weather events could create a threat.
Ultimately, a wide range of activities will be
considered “adaptation,” from relatively simple
operations and maintenance actions such as
ensuring culverts and stormwater drains are
clear of debris, to complex and costly planning
and engineering actions like re-locating a road
alignment away from an area prone to erosion or
sea level rise. Given the broad scope of adaptation
activities, it is important that a comprehensive
decision making approach be formulated that
describes the steps engineers, planners, operations
and maintenance personnel, should take to focus
on the significant risks on the transport system as a
whole and avoid piecemeal decision making. Such
an approach should also be sufficiently flexible
to allow for the consideration of updated climate
change forecasts as well as an examination of a
range of potential cost-effective solutions.
Figure 2.1 Illustration of How Activities to Decrease Likelihood and Consequence Fit Together and Influence the Impacts
and Consequence of Climate Change.(Adapted from (Melillo, Richmond, & Yohe, 2014)
CLIMATE CHANGE RISK ASSESSMENT
7
3. Strategic Context
Understanding our community and customers
needs and the different adaptation strategies that
may be adopted by various transport stakeholders
will be key to ensuring a well functioning transport
system as the backbone for economic activities
and movement of people.
At this stage, the only legislative requirement
in relation to climate change adaptation is the
Victorian Climate Change Act 2010 which requires
the Victorian Government to develop a Climate
Change Adaptation Plan every four years to outline
the potential impacts and risks associated with a
changing climate. The first Victorian Climate Change
Adaptation Plan was released in March 2013 (DSE,
2013) which lists the key risk to roads as being;
From a planning perspective, the risks associated with
climate change was added to the Victorian Planning
Provisions in 2012 (Victorian Planning Provisions
Section 10 Clause 13) to take into consideration the
potential for a 0.8m sea level rise by 2100 and an
additional 0.2m allowance for a 1 in 100 year flood by
2040 for urban infill developments.
In recognising the importance of climate change
and adaptation as both a strategic and operational
risk, VicRoads has integrated climate change
impacts into its existing corporate risk management
framework. This framework has been used as the
basis for determining the significance of climate
change risk to VicRoads assets, using the following
risk categories:
zz Business performance and capability
zz Financial
More frequent extreme weather events may
increase the risk of disruptions to traffic,
increase maintenance and repair costs and
replacement of pavements and structures
(bridges and culverts).
zz Assets
zz Management effort and people
zz Environmental and cultural heritage
zz Legal and compliance
zz Occupational health and safety
In response to this risk, the VicRoads Sustainability
and Climate Change Strategy 2010-2015 was
referenced as the Victorian Government response
for managing risks to roads. However, this
Assessment document was largely focused on
mitigation measures and while mitigation tackles
the causes of climate change, adaptation tackles
the effects of the phenomenon. Climate mitigation
and adaptation should not be seen as alternatives
to each other, as they are not discrete activities
but rather a combined set of actions in an overall
approach to reduce greenhouse gas emissions.
It has since been recognised that a more detailed
approach was required to address the interagency
and statewide risks presented by climate change
(VAGO, 2013).
8
Having identified the risk assessment criteria, this
information was then utilised to assess climate
risks and to document the systematic process
undertaken to determine the need for adaptation
responses and how these will be incorporated into
subsequent policies and procedures for planning,
maintenance or operational personnel. The
systematic approach is outlined in Figure 3.1.
lder Engagem
keho
ent
Sta
Determine risk
assessment criteria
and assumptions
Review
Establish relevant
climate change
projections
Develop adaptation
responses and
implement as planned
Research, monitoring
or periodic review
Prioritising risks based
on asset life and
adaptation window
Establish asset
type categories
Determine susceptible
assets and activities
(RIsks)
Figure 3.1 VicRoads Climate Adaptation Framework
CLIMATE CHANGE RISK ASSESSMENT
9
In addition, the VicRoads Strategic Commitment 2015-2019 has identified four key strategic objectives each
of which can be adversely impacted by climate risk. These are described in more detail in Table 3.1.
Table 3.1 Relationship between VicRoads Strategic Commitment and Climate Change Impacts.
Strategic Commitment
Climate Change Impacts by 2070
Customers & Community
VicRoads recognises the value of engaging with the community
to understand their needs, so climate adaptation responses
developed will provide the better solutions.
We create solutions with our Customers
and Community
Journeys
Enabling integrated transport choices and making
journeys pleasant and predictable
Wellbeing
Improving road safety, amenity and environmental
outcomes
Productivity
Strengthening the economy through better use
of roads and connections with land use
Whilst decreased rainfall and increased temperatures will
overall be a positive influence on travel time predictability, it
is recognised that adverse weather events will create stressful
conditions. Impacts to vegetation may also have an adverse
impact on the amenity of road users.
Increased temperatures will have a positive impact on risks from
black ice and snow. However, in some specific circumstances
there may be temporary increases to aquaplaning risks during
more intense rain events.
There are likely to be increased maintenance requirements
to assets with long design lives or those which are difficult
to adapt, which may impact on the productivity of the road
network. Adverse weather events are also likely to impact
on the productivity of the road network
VicRoads interactive website
is an example of a tool to
address customer needs
for greater and more timely
information regarding
network performance and
availability as a result of
adverse weather events.
10
4. Climate Change Projections
Climate change projections for 2030, 2070
and 2100 have been adopted based on the
Intergovernmental Panel on Climate Change
Fourth Assessment Report (IPCC AR4)1 (Solomon,
et al., 2007). There are a range of future climate
scenarios within the IPCC AR4 projections and
these are shown Figure 4.1. The scenarios are
based on the following assumptions:
zz A1: Rapid economic growth, global population
that peaks in mid-century and declines
thereafter followed by rapid introductions
of new and more efficient technologies
zz A2: A very heterogeneous world with an
emphasis on family values and local
traditions
zz B1: Introduction of clean technologies
zz B2: Emphasis on local solutions to economic
and environmental sustainability
The major underlying themes of the A1 scenarios
are convergence among regions, capacity building,
and increased cultural and social interactions, with
a substantial reduction in regional differences in
per capita income. The A1 scenario develops into
three groups that describe alternative directions
of technological change in the energy system.
The three A1 groups are distinguished by their
technological emphasis: fossil intensive (A1FI), nonfossil energy sources (A1T), or a balance across all
sources (A1B).
VicRoads has adopted the A1FI future climate
scenario, which is based on the continuation of a
fossil intensive energy sector with the generation
of greenhouse gases projected to increase
accordingly. This is a conservative worst case
position projecting the more significant impacts
of climate change. This is consistent with the
approach to climate change accepted elsewhere
within Victoria (SKM, 2012) (CSIRO, 2007 e) and
Australia (DCCEE, 2011). It is also consistent with
fossil fuel emissions data which indicate that global
emissions are still tracking at or above the A1FI
scenario (Global Carbon Project, 2014).
For the purposes of assessing risk to the road
network, the 2070 projections have been adopted
as the most appropriate basis to guide the
development of this Assessment document for
the following reasons:
zz The incremental climate change projections at
2030 generally produce effects that are within
historical operating conditions and would not
require any special actions. The 2030 projections
were therefore considered as not suitable as
an indicator of possible future actions for an
adaptive response.
zz Many of the 2100 model projections diverge
quite widely due to the large degree of
uncertainty. In addition, it was considered that
future changes to other factors affecting road
asset management such as the split of transport
modes, land use, travel patterns etc would also
be a critical input to adaptive responses.
zz 2100 projections were seen to be useful for
reference, but they were not suitable for the
development of specific adaptive responses at
this point in time. Nonetheless, it is recognised
that climate change impacts are forecast up to
and beyond this time.
Exceptions to this approach were:
zz consideration of the effects of sea level rise, for
which there is already a general consensus within
state and federal government departments on
the appropriate amount of sea level rise to adopt
for the year 2100 (Victorian Planning Provisions
Section 10 Clause 13, 2014).
zz Where the only data available for a climatic
parameter is based on 2100 projections, such as
the increased incidence of warm nights over 21°C.
1T
he latest data released in IPCC AR5 shows minor changes from the IPCC AR4 report, but indicates a higher level of certainty regarding
the potential impacts of climate change (Stocker, et al., 2013). The latest predictions for temperature increases are 2.6 to 4.8 °C by 2100,
which has changed from 2.4 to 6.4 °C in the IPCC AR4 report. Projections for sea level rise also remain fairly consistent however, these
are still to be reflected in Australian and Victorian projections and models.
CLIMATE CHANGE RISK ASSESSMENT
11
10
Observed
Fossil fuel emmissions (Gigatonnes Carbon/year)
9.5
IPCC projected emissions
A1FI
9
A1B
A2
B1
A1T
B2
8.5
8
Observed emissions
have outpaced all of
the IPCC projections
for mid 2010
7.5
7
9.14 GtC/y
6.5
6.75 GtC/y
6
6.35 GtC/y
5.5
Figure 4.1 Range of Climate Change Scenarios (Commissioner for Environmental Sustainability Victoria, 2012 - Global Carbon Project)
Currently, Australian data sources such as the
Climate Change in Australia website (CSIRO,
2007 a) and local projections such as the Future
Coasts Program (DEPI a, 2013) have not yet been
republished to reflect the IPCC AR5 projections
and as such they still represent the best level
of publically available data. Data has also been
sourced from other locations where necessary.
There is uncertainty inherent in predicting
climate change. Where available, scenarios with
a range of projections represented as percentiles
have been used to gain confidence in the
projections, however, there were not available
for all parameters. In the vast majority of climate
change parameters with percentiles reviewed,
the percentiles show a clear trend in the one
direction (e.g. all temperature projections are for
a warmer climate). However, in the case of rainfall
it shows that whilst the 10th percentile represents
12
a drier climate, the 90th percentile represents a
wetter climate. A summary of these projections
is presented in Table 4.1. Where available, these
scenarios produce relatively consistent projections
of climate change effects for 2070.
Given that climate change impacts are based on
modelling, the magnitude of these changes and
the certainty of these predictions are represented
as a range of possibilities, diverging towards the
end of the century and beyond. Sea level rise is an
example of this and is virtually certain to extend
beyond 2100 (Stocker, et al., 2013).
A variety of climatic parameters were considered
during the development of this Assessment
document with those seen as relevant to the
road network shown in Table 4.1. A more detailed
description of these climatic parameters are shown
in Sections 6.1 to 6.5.
2015
2010
Mid
2010
2005
2000
1990
Mid
2000
1995
Mid
1990
5
Table 4.1 Summary of Projections of Climatic Parameters used in assessing VicRoads Climate Change Risks
2009*
2030
2070
2100**
Sea Level Rise
0
Storm Surge (Storm Height Return Levels)
1.0 to 2.2 m
+0.15 m^
+0.47 m
+0.82 m
1.2 to 2.3 m
1.6 to 2.7 m
+0.3 to 1.0
+0.6 to 1.0
+1.5 to 2
+1.5 to 2.5
+2.0 to 4.0
+3 to 5°C
Sea level rise
Temperature Average Annual Temperature (°C)
10th percentile
50th percentile
90th percentile
0
The frequency of very hot days
over 35°C Melbourne (Mildura)
9 (32) days
12# (39) days
20 (60) days
The incidence of heatwaves
(>5 consecutive days over 35°C)
1
1
1 to 2
The incidence of warm nights over 21°C
0
-
-
Humidity levels (% Change)
10th percentile
50th percentile
90th percentile
0
-0.5 to 0.5
-1.0 to 0.5
-2.0 to -0.5
-0.5 to 0.0
-2.0 to -0.5
- >4 to -1 %
-10 to -20%
-0.2 to +0.5%
-2 to +5%
-20 to -40%
-10 to -20%
-5 to +40%
+15-50%
Rainfall
Annual rainfall volume
10th percentile
50th percentile
90th percentile
0
Heavy Rainfall Intensity (99th percentile)
0
+1%
+6.5%
-
Number of Rainy Days (>1 mm rainfall)
0
-5%
-17%
-
Evapotranspiration levels
0
+4 to 8%
+12 to >16 %
-
14.8 (56.6)
15.7 to 18.6 #
(59.5 to 66.9) #
16.2 to 23.6 ##
(62.3 to 90.5) ##
-
+2 to 5%
-2 to +2%
-15 to -5%
+10 to 15%
-5 to +2%
>-15 to -10%
-
Fire risk
The Projected Number of high and extreme
fire risk days in Melbourne (Mildura)
Wind speed
10 metres above ground
10th percentile
50th percentile
90th percentile
0
-
Radiation
Radiation levels. Estimated
[Annual Average Noon UV Index (x 25 mWm-2)]
10th percentile
50th percentile
90th percentile
0 [6.5]
+1% [6.6]
+1% [6.6]
+2% [6.6]
+1% [6.6]
+5% [6.8]
+10% [7.2]
*2009 in reality is a twenty year average from 1990-2010, used mostly as a baseline reference
^ sea level rise data point is for 2040.
** 2100 is included in the table for sea level rise and the incidence of warm nights where no earlier projections are available
# data point is for 2020 ## data point is for 2050
CLIMATE CHANGE RISK ASSESSMENT
13
5. Climate Change
Risk Assessment
Over the past five years Victoria has experienced a
number of occurrences of abnormal weather, which,
in a number of cases, are similar to or worse than the
projected future climatic parameters, including;
zz the Millennium drought from 1995 to 2009,
resulting in significantly drier conditions across
the state and degraded vegetation;
zz seven of the ten hottest years on record have
occurred since 1998;
zz the 2011 floods which impacted a significant
portion of the state and resulted in the closure
of some regional roads for significant periods
of time to clear landslides and rebuild roads
and bridges;.
zz the high temperature conditions experienced
in Victoria in 2009, with the hottest day ever
recorded at 45.8 oC which is even higher than
the long range projections;
zz the record heatwave temperatures of January
2014 with four days in a row of over 40oC,
which resulted in several road closures for
softened pavements and contributed to
pavement surface tearing on the Westgate
Bridge; and,
zz the significant bushfires experienced in 2009
with the Black Saturday fires resulting in 173
fatalities and burned over 450,000 hectares
including VicRoads roadside assets as well as
other infrastructure.
14
In the case of these recently experienced weather
occurrences, they are typical of conditions
elsewhere in the world or indeed in Australia.
Under climate change projections, they are also
likely to be reflective of conditions experienced
more frequently in Victoria. It is also recognised
that VicRoads has historically experienced weather
related road network interruptions such as storm
surges, black ice, snow, storm surge or localised
flooding. This highlights specific susceptible
locations that will be monitored for any changes in
frequency or severity of interruptions.
An analysis of weather related road closures
between December 2011 and May 2014
is presented in Figure 5.1 and Figure 5.2
demonstrating that road closures are related
primarily to rainfall and flooding.
Given the number of assets, size and the
geographic diversity of Victoria, the number of
occurrences of abnormal weather events as well
as the projected climate changes, it is necessary
for VicRoads to have a sound basis for determining
risk, what adaptation should occur and when it
should occur, in order to address these risks.
Flood damage
3%
Temperature
(Fire and soft pavement)
6%
Landslip
Water on road
8%
70%
Winter weather
(snow and ice on road)
13%
Figure 5.1 Road Closures Related to Climate Parameters
Landslip
Storm event
1%
3%
Snow
3%
Fire
14%
Floodwater
51%
Flood damage
28%
Figure 5.2 Road Hazards Related to Climate Parameters
CLIMATE CHANGE RISK ASSESSMENT
15
Whilst past experience is valuable as a predictor
of future climate and weather it may not be
sufficient. As noted above, weather conditions and
specifically extreme weather events are already
a primary cause of disruption and road agencies
such as VicRoads already dedicate resources to
anticipate their impacts and adapt infrastructure
and operations. However, due to the projected
magnitude of climate change and taking into
account the degree of uncertainty, an incremental
approach based on traditional practice is not
expected to be effective in the future. Therefore,
innovative and broader approaches to adaptation
are needed potentially leading to structural changes
in transport services and strengthened cooperation
with other sectors (EEA, 2014).
16
At this point in time, VicRoads along with other
road agencies in Australia is involved in the
development, modification and adoption of road
design standards and guidelines. The drainage
section of the Austroads Guide to Road Design
(ARRB, 2013), already includes sections on climate
change, in particular how rainfall intensity will
change across catchments and work is underway
to review the Australian Standard for Bridge Design
(AS 5100), specifically requiring consideration of
climate change impacts in future design.
…. consideration of sustainability and climate
change ensure that these important aspects
will be incorporated into designs and reduce
the risk of occupational health and safety issues
and level of service issues of the structures we
design (Powers & Rapattoni, 2014).
5.1 Asset information
VicRoads categorises its assets broadly into seven categories with each having a number of subcategories.
These have been used to assess risks within the framework, as described in Table 5.1.
Table 5.1 Description of VicRoads Asset Categories
Asset Type
Description
Subcategories
Road Pavements
Road Pavement Layers are made up of compacted layers of structural
fill and crushed rock. The purpose of the road pavement is to carry and
distribute wheel loads without deforming and causing damage to the
surface layers.
Concrete Road
The purpose of the road surfacing is to provide a low maintenance allweather riding surface, which protects the underlying structural road
pavement from ingress of free water. Water weakens the unbound
material, causing potholes, ruts and corrugations.
Concrete Road
The surfaces of the 22,500 kilometres of main roads are designed to
shed water off the pavement and to ensure safe travel for vehicles
during rainfall events. In urban areas, the concentrated flows are
collected in concrete channels adjacent to kerbing which lead to
underground pipe systems. In most of the rural areas, the concentrated
flows are collected in earth lined open drains that carry the collected
water to local streams and channels.
Surface Flow
VicRoads manages about 80,000 hectares of road reservation and has
planted more than 8 million trees and shrubs. These road reserves also
contain significant tracts of landscaped and remnant native vegetation.
Naturally Landscaped Areas
Roadsides also provide areas for placement of signs and safety barriers,
for landscaping and amenity, footpaths and bicycle paths, visual
screening, as well areas for the safe recovery for errant vehicles. They
are also an important location for public utilities such as power, gas,
and telecommunication cables.
Grassed Areas
Road Surfacing
Layers
Drainage
Roadsides
Asphalt Road
Spray Seal Road
Unsealed Road
Asphalt Road
Spray Seal Road
Unsealed Road
Underground Drains
Special Drainage Structures
Planted and Landscaped
Areas
Natural Slopes
Paved Areas
Road Signs
Fauna Sensitive Features
Pavement Markings
Safety Barriers
Property Fences
Structures
VicRoads manages around 3200 bridges on the main road network
and more than 4500 other structures such as large culverts, steel
gantries and cantilever sign supports, retaining walls and noise barriers.
Road Bridge
Bridge over Waterway
Large Culvert
Major Sign Support
Noise Walls
Retaining Walls and Structural
Safety Barriers
High Mast Lighting
ITS/Electrical Assets
VicRoads Activities
There are around 3500 sets of traffic signals on the main road network.
In addition, there are around 4400 on-road electrical devices such as
illuminated or dynamic road signs, CCTV monitoring cameras, help
phones and various vehicle detection and warning systems, and 70000
street lights (around 90% of these have shared responsibility with local
councils).
Electrical (i.e. street lighting,
pits and cables)
VicRoads manages a construction and maintenance program to value
of around $1.5 Billion per annum including 22,500 kilometres of road
and assets valued at over $45 billion.
Planning and Design
Electronic (i.e. solar
installations, height detection
devices)
Mechanical (i.e. pumps)
Construction
Maintenance
Operations
CLIMATE CHANGE RISK ASSESSMENT
17
For each of these asset categories an assessment
has been undertaken to identify those susceptible
assets and activities which are likely to be negatively
affected by climate change. For risk identification, a
combination of the following techniques was used
zz Brainstorming outcomes based on facilitated
workshop
zz Adapted Delphi technique – where risks and
predicted outcomes were re-circulated among
the experts for comment to achieve a consensus
of opinion and ensuring that no one person had
undue influence on the outcome
zz Interviews with key technical experts
zz Interviews with key external stakeholders
including Wyndham City Council; Victorian
Centre for Climate Change Adaptation and
Research; Association of Bayside Municipalities;
Westernport Local Coastal Hazard Assessment
Group; Western Alliance for Greenhouse
Adaptation; and Climate Resilient Communities
of the Barwon South West.
As part of the subsequent risk analysis,
consideration was given to the asset life. Each
asset within VicRoads has a designed or expected
life which varies greatly depending on the type of
asset. For example electrical Intelligent Transport
System (ITS) assets have a design life of ten year or
less, whereas some structural assets have a design
life of 100 years or more. Figure 5.1 shows the
range of design life for different asset categories;
for example structures are expected to last 30 to
100 years, while concrete stormwater drainage
has a life of 80-100 years. The diagrammatic
representation of the assets also shows that in
the case of assets like ITS with a short life, there
is plenty of time to implement modification to
asset specifications to cope with climate change
impacts and as such, based on current climate
change projections adaptation for ITS assets does
not need to be considered until around the year
2050. By comparison, for longer lived asset types
like drainage, adaptation actions will need to
commence within the next fifteen years to ensure
these actions are effective in managing risk.
zz Root cause analysis – for identifying a problem
and discovering the causes that led to it
The initial identification of susceptible assets and
activities found a significant number of risks existed
across a wide range of assets types. The distribution
of risk level by asset type is summarised in Table
5.2. The detailed risk assessments are contained
in Sections 6.1 to 6.5.
Table 5.2 Distribution of Risk Level by Asset Type
Asset Type
18
Significant
Risks (#)
Road Pavements
1
Important
Risks (#)
1
Insignificant
Risks (#)
3
Positive
Benefits (#)
1
Road Surfacing Layers
2
2
1
-
Drainage
1
2
2
-
Roadsides
-
3
2
-
Structures
1
1
3
-
ITS/Electrical Assets
1
3
1
-
VicRoads Activities
1
3
1
4
Total
7
15
13
5
Legend
ITS
The number of years
before adaptation would
need to start or occur
Road surfacing
The expected or design
life of an asset class
Roadsides
- landscaping
Road Structural
Component
Drainage
Roadsides
- remnant/vegetation
Structures
20
40
60
80
100
120
Years
Figure 5.3 Design Life of Different VicRoads Asset Categories.(Adapted from (UK Highways Agency, 2011))
CLIMATE CHANGE RISK ASSESSMENT
19
6. Detailed Risk Assessment
6.1 Sea Level Risk
More detailed information on projected changes
to climate parameters was used to assist in the
detailed assessment of risks, with this being used to
inform the prioritisation of a number of these risks.
All descriptions are described in terms of
how they affect road infrastructure, relative
to the period 1980-1999 (referred to as the
1990 baseline for convenience).
The 50th percentile (the mid-point of
the spread of model results) provides a
best estimate result. The 10th and 90th
percentiles (lowest 10% and highest 10% of
the spread of model results) provide a range
of uncertainty.
All CSIRO sourced data is produced with
permission from CSIRO Australia.
Background planning and
detailed modelling (2 years)
Of all the climate change parameters, sea level
rise is likely to have the greatest impact on the
performance of the road network. A summary
of the risks posed to infrastructure types by sea
level rise is summarised in Table 6.1. Even though
these impacts are limited to road assets in lowerlying coastal regions in the majority of cases, the
consequences are significant because many of the
affected roads in these regions form vital transport
and accessibility links on the main road network.
The Victorian Planning Provisions Section 10
requires an allowance for possible sea level rise.
This is 0.2 m by 2040 for urban infill projects
and 0.8m by 2100 for coastal projects (Victorian
Planning Provisions Section 10 Clause 13, 2014).
Figure 6.1 shows a timeline of sea level rise impacts
for the IPCC AR4 and IPCC AR5 projections as well
as the likely timeframe required to adequately adapt
to sea level rise. For example, if the predicted level
of impact associated with a 0.2m sea level rise was
to occur at the earliest predicted timeframe i.e.
2034, then investigation of adaptation measures
should commence for this by 2024 to ensure
adequate time for project planning, funding and
implementation. It is also worth noting that if sea
level rise continues at its current rate, then 0.2 m
or sea level rise will occur by 2060.
Background planning and
detailed modelling (2 years)
Business cases (4 years)
Business cases (4 years)
Detailed design (2 years)
Detailed design (2 years)
Construction (2 years)
2014
2020
2030
2040
Construction (2 years)
2050
2060
2070
Range for 0.2m SLR
2080
2090
2100
Range for 0.47m SLR
(2013 data) IPCC ARS RCP 8.5 scenario
Sea Level Rise
0.2m
0.47m
(2007 data) IPCC AR4 A1FI scenario
Figure 6.1: Comparison of IPCC AR4 and AR5 Sea Level Rise Projections and Time Implications for Adaptation
20
0.82m
Table 6.1: Summary of Sea Level Rise Related Risks to Infrastructure Types
Consequences
Actions
Risk
Road Surfacing
Sea Level Rise may result in mechanical damage to
road surfaces through wave action or storm surge.
This potential will be limited to locations where sea
level rises sufficiently to inundate the road pavement.
The ingress of salt into road pavement material
below the road surface due to higher sea levels has
the potential to cause de-lamination of the road
surfacing. However, this is a very rare occurrence.
Significant
Pavement Structure
Sea Level Rise may result in mechanical damage such
as scour or erosion to road pavements as a result
of wave action or storm surge. This potential will be
limited to locations where sea level rises sufficiently
to reach the road pavement
Investigate need to
construct protective
measures. Consult
with state and local
government over
options to rebuild or
realign affected routes
clear of tide and storm
surge levels.
Drainage
One of the early impacts of sea level rise may
be the reduced capacity of coastal or low lying
drainage networks with submerged outfalls. This
will increase the likelihood of flooding during rain
events, especially at high tide times. This risk is likely
to become apparent well before the risks associated
with the overtopping of road pavements
Structures
Overtopping by sea water, especially of embankments
and approaches may pose a problem in some areas.
- Scour due to storm surge could cause instability
and failure for structures like bridges, culverts and
retaining walls
- Changes in salinity of groundwater, and the height
of the tidal zone may increase the risk of corrosion in
some coastal areas.
Operations
Planning of new infrastructure and approval of local
government development proposals will need to take
account of changes to the road network associated
with sea level rise. Many of these decisions may
involve multiple agencies, or may be dependent on
strategies to be developed by or in conjunction with
third parties. Experience has shown that these issues
may take many years to resolve.
ITS/Electrical Assets
Some cables and signal and lighting hardware may
be affected, particularly in urban areas.
There are no significant risks to ITS assets from
sea level rise as no ITS assets are located close to
the coast.
No action required
at this stage
Insignificant
Sea Level Rise may result in mechanical damage to
roadside assets including signs and safety barriers.
Vegetation management may also be impacted
by rising water table, increasing salt levels, and
inundation.
No action required
at this stage
Important
Roadsides
Roadsides will be managed by VicRoads as part of
the overall sea level rise risk, as it is required within
the road network.
CLIMATE CHANGE RISK ASSESSMENT
21
The expected sea level rise and storm surge
impacts expected in Victoria are described in Table
4.1. Table 6.2 and Table 6.3 show VicRoads analysis
of the estimated impact of storm surge and sea
level rise on the Victorian main road network.
They are based on analysis by VicRoads using the
Victorian Coastal Inundation Dataset (DEPI b, 2013)
and as such are a conservative estimate.
The impacts are likely to be the highest in the
Eastern Region, accounting for approximately half
of all projected impacts. This includes a number
of Gippsland regional locations such as Lakes
Entrance, Tooradin and near Tarwin Lower.
Urban areas likely to be impacted include
Williamstown, St Kilda, Elwood and Edithvale.
There is also projected impact to locations such
as Queenscliff and the Great Ocean Road.
Based on the projections of 0.82m of sea level
rise, it is estimated that inundation would impact
26 roads, directly affecting around 14 kilometres in
carriageway length. An additional ten kilometres of
roads are likely to have impact to subgrades and
batters at this time, as well as damage to other
assets in the vicinity.
Table 6.2: Estimated Sea Level Rise Impacts on Main Roads by Region
VicRoads
0.2m Sea level rise
0.47m Sea level rise
0.82m Sea level rise
Eastern Region
0.0
2.5
6.8
Metro South East
0.2
0.5
1.2
Metro North West
0.0
0
2.1
South Western Region
1.0
1.8
3.7
TOTAL km
1.2 (5 roads)
4.8 (12 roads)
13.8 (26 roads)
Although the impacts of inundation due to
rising sea levels may not become obvious for
many decades, other adverse impacts may be
experienced much earlier, in fact a number of
locations already experience storm surges impacts,
resulting in periodic road closures or traffic hazard
speed reductions. There are also locations along
the Great Ocean Road, such as Port Campbell
where the road has been realigned to address
existing coastal erosion risks.
Storm surge is also likely to increase from the
current 1.0 to 2.1 m to 1.6 to 2.7 m by 2070, with
the highest surges predicted between Lorne and
Loch Sport (Department of Sustainability and
Environment, 2012). The impact of storm surges is
also predicted to increase, with sea level rise. Based
on the projections of 0.8 m of sea level rise it is
estimated that 62 roads, with 89.6 kilometre length
would be impacted by 1 in 100 year storm events.
The impacts of sea level rise and storm surge are
not uniform across the Victorian Coast.
Table 6.3: Estimated Storm Surge Impacts on Main Roads by Region
VicRoads
22
0.2m Sea level rise
0.47m Sea level rise
0.82m Sea level rise
Eastern Region
17.3
31.2
44.9
Metro South East
1.3
4.4
11.2
Metro North West
0.5
3.2
19.8
South Western Region
3.9
6.7
13.6
TOTAL km
23.0 (30 roads)
45.6 (42 roads)
89.6 (62 roads)
It is also predicted that sea level rise will lead to
erosion of new sections of coastline and this will lead
over time to collapse of infrastructure in susceptible
locations. Erosion is also predicted to undermine over
two kilometres of the Great Ocean Road by 2040 and
13 kilometres by 2100 (SKM, 2012). Table 6.4 shows
the composition of the Victorian coastline, which is
heterogeneous, with the western part of the state
having more rocky coastlines,
Westernport Bay being muddy, and becoming
sandier towards the east of the state. Some of the
specific coastal areas predicted to be impacted
are also listed in Table 6.5 and underline the need
to consider the particular nature of the coastal
geology when determining adaptation response.
Sandy
and
Muddy
Coasts
West of Cape
Otway
Cape Otway
to Torquay
Torquay to
Westernport
Westernport to
Lakes Entrance
East of Lakes
Entrance
Rocky
Coasts
# Victorian
Coastline
Table 6.4: Victorian Coastline Type by Regional Area
Hard rock cliffs
22%
39%
17%
6%
15%
16%
Soft rock cliffs
6%
26%
18%
8%
0%
4%
Sandy shores backed
by soft sediment
30%
1%
10%
46%
18%
59%
Sandy coast/ shores
backed by rock
21%
34%
55%
30%
10%
21%
Muddy Sedimentary
shores (e.g. tidal flats)
22%
0%
0%
10%
57%
0%
Based on OzCoasts Data (OzCoasts, 2013)
# Sourced from (Department of Sustainability and Environment, 2012)
Apollo Bay
Skenes Creek
Kennett River
Wye River
Angelsea
Barwon Heads
Queenscliff
Inverloch –
Venus Bay Road
Rocky
Coasts
Peterborough
Table 6.5: Coastline Compositions at Locations Projected to be Impacted by Sea Level Rise
0%
0%
0%
36%
8%
0%
0%
0%
0%
33%
8%
5%
0%
0%
0%
0%
0%
0%
Sandy shores backed
by soft sediment
53%
48%
71%
2%
4%
21%
100%
94%
86%
Sandy coast/ shores
backed by rock
14%
44%
24%
62%
88%
79%
0%
6%
13%
Muddy Sedimentary
shores (e.g. tidal flats)
0%
0%
0%
0%
0%
0%
0%
0%
1%
Hard rock cliffs
Soft rock cliffs
Sandy
and
Muddy
Coasts
Based on OzCoasts data (OzCoasts, 2013)
CLIMATE CHANGE RISK ASSESSMENT
23
The cost impact of storm surge events would be
expected to rise as greater lengths of road are
impacted by storm surge events. Within the Great
Ocean Road an additional 13.8km of road length
would be susceptible to 1 in 100 year storm surge
events (SKM, 2012). These events would also affect
other co-located roadside assets such as batters with
geotechnical risk, structures, vegetation and fencing.
Many VicRoads drainage networks discharge into
drainage systems managed by local government
or other government agencies. As such, the
infrastructure likely to be damaged by flooding of
the road drainage system includes infrastructure
other than roads with buildings, agricultural land and
commercial and industrial developments close to
coastal areas also under threat. At many locations,
VicRoads will not be able to take independent action
to address this issue and it will require a coordinated
approach to determine the most efficient solutions
involving all interested parties.
6.2 Temperature
A summary of the risks posed to Infrastructure
types from rainfall is shown in Table 6.6. This is
based on an assessment of information on rainfall
volumes, intensity, humidity and evapotranspiration
shown in Table 4.1, and supported by the additional
analysis below.
Average temperatures in Victoria are predicted to
rise by between 1.5 and 2 °C on average across the
state by 2030 and by 3 and 5 °C on average across
the state by 2070 at the 90th percentile. There will
also be a corresponding increase in warm days.
These are based on CSIRO modelling, shown in
Table 4.1, and represent the worst case scenario.
It is also expected that hot spells (a period a 3 to 5
consecutive days where the temperature exceeds
35 oC) will double from 1 to 2 by 2070. Night
time temperatures in Australia are expected to rise
with warm nights (>21 °C) projected to increase
between 15-50 per cent at the end of the 21st
Century (Maunsell, 2008), as shown in Table 4.1.
Table 6.6 : Summary of Temperature Related Risks to Infrastructure Types
24
Consequences
Actions
Risk
Road Surfacing
Greater potential for damage under heavy wheel loads.
No action required at
this stage
Important
Pavement Structure
No significant consequences
No action required
Insignificant
Drainage
No significant consequences
No action required
Insignificant
Roadsides
Combined with lower rainfall will result in the loss of many
plant species and less vigorous growth of many of the
survivors. This could result in greater erosion, landslips,
increased fire risk, issues with management of pest plants
and animals, loss of landscape amenity.
Investigate
vulnerable species,
locations. Possible
alternative plantings
at key locations.
Significant
Structures
No significant consequences
No action required
Insignificant
ITS/Electrical Assets
Extended high temperatures may have an adverse impact
on the operation of some electrical equipment, such as
components in traffic control cabinets or LED’s used in
traffic and street lighting.
No action required at
this stage.
Important
Operations
Heat Stress may become a major health issue especially in
inner urban areas with the urban heat island effect playing
a major role.
OH&S provision for Field workers may require change.
Maintenance timeframes may decrease due to the impact
on assets such as LED’s in street and traffic lighting.
Investigate possible
actions to ameliorate
urban heat island
effect and the
contribution of roads
to this.
Important
Extended season for temperature sensitive works such as
laying bitumen/asphalt
No action required at
this stage.
Positive
Decreased risk of black ice on roads
No action required
Positive
6.3 Rainfall
A summary of the risks posed to Infrastructure
types from rainfall is shown in Table 6.7. This is
based on an assessment of information on rainfall
volumes, intensity, humidity and evapotranspiration
shown in Table 4.1, and supported by the additional
analysis below.
Table 4.1 shows there may be less annual rainfall
volume, but rainfall events are likely to be become
more intense with a higher risk of localised and
widespread flooding. Extreme rainfall events
will also become 30% more intense by 2030. In
this timeframe it is anticipated that the extent of
flooding will be 25% larger for 1 in 5 year events and
15% larger for 1 in 100 year events in Melbourne
urban catchments. It is also suggested that the
frequency of a current 1 in 100 year rainfall event
will double (Pedruco & Watkinson, 2010).
Annual rainfall volume is likely to decrease in
Victoria. It is predicted to decrease by 0.2 to 0.5%
by 2030 and by 10 to 20% by 2070 for the 50th
percentile based on CSIRO modelling, as shown
in Table 4.1.
However, for the worst case scenario is represented
by the based 10th and 90th percentile of data the
rainfall volume will be somewhere between a 20%
increase and a 40% decrease, with the forecast
increases in the 90th percentile largely falling within
existing design parameters..
Overall rainfall intensity will increase by about 1% in
Victoria by 2030 and about 6.5% by 2070 relative to
a 1990 baseline as shown in Table 6.8. The number
of rainy days will decrease by about 5% by 2030
and about 17% by 2070 relative to a 1990 baseline
as shown in Table 6.9.
Humidity levels are forecast to reduce slightly, with a
less than a five percent decrease by 2070 at the 10th
percentile, based on CSIRO modelling and shown in
Table 4.1. This represents the worst case scenario.
Evapotranspiration levels are predicted to increase
with a greater than 16% change by 2070 at the
90th percentile, based on CSIRO modelling and
shown in Table 4.1. This is projected to result in an
increased movement of water to the atmosphere
from both water bodies and from vegetation, and
represents the worst case scenario.
Table 6.7: Summary of Rainfall Related Risks to Infrastructure Types
Consequences
Actions
Risk
Road Surfacing
No significant consequences
No action required
Insignificant
Pavement Structure
More intense rainfall patterns could result in ponding of water at some
locations, with the possibility of pavements being weakened in local
areas.
If the increased intensity of rainfall events result in ponding of surface
water adjacent to pavements, this could result in increased rates of
pavement deterioration at the locations where the ponding occurs. In
most instances, good drainage maintenance practice would reduce
this issue from occurring.
Attention to maintenance
of drainage systems in
vulnerable areas.
Insignificant
Overall drier conditions will result in longer pavement life.
No action required
Positive
Drainage
More intense rainfall could result in localised flooding, damage due to Investigate locations of
scour, less safe running conditions for traffic during rainstorms on wide vulnerability, possible
flat pavements.
protective measures, traffic
management measures
Important
Roadsides
Combined with higher temperature will result in the loss of many
plant species and less vigorous growth of many of the survivors. This
could result in greater erosion, landslips, increased fire risk, issues with
management of pest plants and animals, loss of landscape amenity.
Important
Structures
More intense rainfall could result in localised flooding, damage due to Investigate locations of
scour, less safe running conditions for traffic during rainstorms on wide vulnerability, possible
flat pavements.
protective measures, traffic
management measures
Insignificant
ITS/Electrical Assets
No significant consequences
No action required
Insignificant
Operations
Less natural water available for maintenance and construction
Possible need to harvest rainfall runoff from road.
No action required at this
stage.
Important
Fewer rain related delays to construction and maintenance works.
No action required
Positive
Investigate vulnerable
species, locations. Possible
alternative plantings at key
locations.
CLIMATE CHANGE RISK ASSESSMENT
25
Table 6.8: Summary of Projected Rainfall Intensity Changes
Rainfall Intensity (%) [10th to 90th percentile]
Region
Location
2030 Medium
2070 low
2070 high
Port Phillip and Westernport
Melbourne
0.9 [-7.7 to 15.2]
3 [-12.9 to 25.3]
5.9 [-24.9 to 48.9]
Scoresby
0.8 [-7.7 to 14.8]
2.6 [-12.8 to 24.7]
5 [-24.7 to 47.7]
Cape Schanck
0.7 [-9.7 to 14.9]
2.3 [-16.2 to 24.8]
4.5 [-31.4 to 47.9]
Ballarat
1.5 [-10.5 to 15.8]
5 [-17.4 to 26.4]
9.6 [-33.7 to 51]
Lismore
1.3 [-10.3 to 15.6]
4.5 [-17.1 to 26.1]
8.6 [-33.1 to 50.4]
Ararat
1.1 [-6.8 to 15.8]
3.6 [-11.3 to 26.4]
6.9 [-21.8 to 51]
Hamilton
1.5 [-7.3 to 15.5]
5 [-12.1 to 25.9]
9.7 [-23.4 to 50]
Warrnambool
3.1 [-10.2 to 16]
5.2 [-17 to 26.7]
10.2 [-32.8 to 51.5]
Wimmera
Horsham
0.6 [-8.8 to 14.8]
2.1 [-14.7 to 24.7]
4 [-28.4 to 47.7]
Mallee
Mildura
-0.3 [-11.1 to 16.1]
-1.1 [-18.5 to 26.8]
-2 [-35.7 to 51.8]
Ouyen
-0.3 [-9.6 to 15.6]
-1.1 [-16 to 25.9]
-2.1 [-31 to 50.2]
Donald
0.6 [-11.2 to 15.2]
2 [-18.7 to 25.4]
3.9 [-36.2 to 49.1]
Bendigo
1.1 [-7.2 to 15.9]
3.6 [-12.0 to 26.6]
6.9 [-23.3 to 51.4]
Swan Hill
0.6 [-8.5 to 15.3]
1.9 [-14.2 to 25.5]
3.6 [-27.4 to 49.3]
Tatura
0.8 [-7.1 to 14.6]
2.8 [-11.9 to 24.4]
5.3 [-23 to 47.1]
Benalla
0.9 [-9.0 to 13.5]
3.2 [-15.0 to 22.4]
6.1 [-29 to 43.4]
Mangalore
1.2 [-7.1 to 15.1]
3.8 [-11.9 to 25.2]
7.4 [-22.9 to 48.7]
Beechworth
1.4 [-10.1 to 14.4]
4.8 [-16.8 to +24.0]
9.2 [-32.4 to +46.3]
Rutherglen
1.5 [-9.8 to 14.4]
5.1 [-16.4 to +24.0]
9.9 [-31.7 to 46.4]
Omeo
2.1 [-8.6 to 17.5]
7 [-14.3 to 29.2]
13.6 [-27.7 to 56.4]
Orbost
1.0 [-7.4 to +19.2]
3.2 [-12.3 to 32.0]
6.2 [-23.8 to 61.8]
Lakes Entrance
1.5 [-7.7 to +18.4]
4.9 [-12.8 to 30.7]
9.5 [-24.7 to 59.4]
Wonthaggi
0.4 [-7.7 to 14.3]
1.4 [-12.8 to 23.8]
2.7 [-24.8 to 46.0]
Sale
1.5 [-5.3 to 16.6]
4.9 [-8.8 to 27.7]
9.4 [-17.0 to 53.5]
Corangamite
Glenelg Hopkins
North Central
Goulburn Broken
North East
East Gippsland
West Gippsland
Source Regional Climate Change Projection Publications by Region (DSE a,b,c,d,e,f,g,h,I,j, 2008)
26
Table 6.9: Summary of Projected Changes to the Number of Rainy Days
Rainfall Intensity (%) [10th to 90th percentile]
Region
Location
2030 Medium
2070 low
2070 high
Port Phillip and Westernport
Melbourne
-6 [-17 to -1]
-10 [-28 to -2]
-19 [-54 to -4]
Scoresby
-6 [-16 to -1]
-10 [-26 to -2]
-19 [-51 to -4]
Cape Schanck
-6 [-13 to -1]
-10 [-22 to -2]
-19 [-43 to 5]
Ballarat
-5 [-17 to -1]
-9 [-28 to -2]
-18 [-54 to -5]
Lismore
-5 -[15 to -2]
‘-9 [-25 to -3]
-17 -[48 to -5]
Ararat
-6 [-13 to -1]
-10 [-22 to -2]
-18 [-43 to -5]
Hamilton
-5 [-17 to -2]
-8 [-28 to -3]
-16 [-54 to -5]
Warrnambool
-5 [-17 to -1]
-9 [-29 to -2]
-18 [-56 to -4]
Wimmera
Horsham
-6 [-19 to -1]
-10 [-31 to -2]
-19 [-61 to -4]
Mallee
Mildura
-6 [-21 to 0]
-10 [-35 to 1]
-19 [-68 to 2]
Ouyen
-7 [-20 to -1]
-11 [-33 to -1]
-21 [-64 to -2]
Swan Hill
-6 [-20 to -1]
-10 [-34 to -1]
-18 [-66 to -2]
Donald
-6 [-18 to -1]
-9 [-31 to -2]
-18 [-83 to -6]
Bendigo
-5 [-17 to -1]
-8 [-29 to -2]
-16 [-56 to -4]
Tatura
-5 [-17 to -1]
-9 [-29 to -2]
-17 [-56 to -3]
Benalla
-5 [-18 to -1]
-8 [-30 to -2]
-16 [-57 to -3]
Mangalore
-5 [-17 to -1]
-8 [-29 to -2]
-16 [-56 to -4]
Rutherglen
-5 [-18 to -1]
-8 [-30 to -2]
-16 [-57 to -3]
Beechworth
-5 [-18 to -1]
-8 [-28 to -2]
-16 [-57 to -3]
Omeo
-5 [-17 to -1]
-8 [-28 to -2]
-15 [-54 to -3]
Orbost
-5 [-16 to -1]
-8 [-26 to -1]
-15 [-51 to -2]
Lakes Entrance
-5 [-16 to -1]
-8 [-26 to -1]
-15 [-51 to -3]
Wonthaggi
-5 [-14 to -1]
-9 [-23 to -2]
-18 [-44 to -5]
Sale
-5 [-13 to -1]
-8 [-21 to -2]
-16 [-41 to -2]
Corangamite
Glenelg Hopkins
North Central
Goulburn Broken
North East
East Gippsland
West Gippsland
Source Regional Climate Change Projection Publications by Region (DSE, a,b,c,d,e,f,g,h,I,j, 2008)
CLIMATE CHANGE RISK ASSESSMENT
27
6.4 Extreme Weather Events
A summary of the risks to VicRoads infrastructure
from extreme weather is shown in Table 6.10, based
on wind speed, fire risk and changes to rainfall
intensity. This section considers rainfall relating to
extreme events as discussed in section 6.3.
Wind speed analysis is based on CSIRO modelling
(CSIRO, 2007 a), in Table 4.1. This shows an
increase in wind speeds measured 10 metres above
the ground of up to five percent by 2030 and ten
to 15 percent by 2070 at the 90th percentile, and
represents the worst case scenario.
The Forest Fire Danger Index (FFDI) is predicted to
increase, and this will result in a likelihood of more
fire events across Victoria. Table 6.11 shows high
and extreme fire risk days and Table 6.12 shows
only extreme fire risk days, and both predict an
increase in risks through to 2070. For example, in
Bendigo the number of days experiencing high
or extreme fire weather is predicted to increase
from 14 days to 19 days annually by 2020 and 29
by 2050 in a worst case scenario, and the number
of extreme fire risk days is predicted to increase to
between 1.5 and 2 by 2020 and 1.6 and 4 by 2050.
Table 6.10: Summary of Extreme Weather Related Risks to Infrastructure Types
Consequences
Road Surfacing
Pavement Structure
Actions
Risk
Increased bushfires and flood may cause more
Investigate locations of
frequent and more extensive damage to road surfaces vulnerability, possible
Greater likelihood of widespread flooding could result protective measures, and
flood flow management
in pavement damage and long term reduction of life
measures.
for affected pavements.
Drainage
Greater likelihood of widespread flooding could
result in damage to drainage systems.
Roadsides
Greater likelihood of bushfires, floods and storms will
cause difficult conditions for many plants and animals.
Structures
Greater likelihood of widespread flooding and
storms could result in damage to structures and their
footings.
ITS/Electrical Assets
Greater reliance on traffic management systems
to reduce congestion, ensure smooth traffic flow
especially during extreme weather and emergency
management events
Investigate potential
locations for installation
of uninterrupted power
supply
Important
Operations
Greater pressure on emergency response resources.
No action required
at this stage.
Important
Decreased operational impacts of black ice and snow
on roads
No action required
Positive
Table 6.11: Summary of Projected High and Extreme Fire Days (CSIRO, 2007 b)
28
Important
Location
Present (1973 – 2007)
2020
2050
Melbourne Airport
14.8
15.7 to 18.6
16.2 to 23.6
Mildura
56.6
59.5 to 66.9
62.3 to 90.5
Laverton
11.8
12 to 13.6
12.4 to 19.2
Bendigo
13.9
15.6 to 18.4
16.6 to 28.6
Sale
5.4
5.4 to 7.1
5.7 to 11.1
Table 6.12: Summary of Projected Extreme Fire Days (CSIRO, 2007 b)
Location
Present (1973 – 2007)
2020
2050
Melbourne Airport
2.5
2.8-3.4
3 to 5.8
Mildura
7.3
8.0 to 10.0
8.6 to 15.9
Laverton
1.9
1.9 to 2.6
2.2 to 4.6
Bendigo
1.2
1.5 to 2.0
1.6 to 4.0
Sale
0.6
0.6 to 0.9
0.6 to 1.9
6.5 UV Level
A summary of the Risks by Asset types is shown
in Table 6.13. This is supported by the prediction
that downward solar radiation will increase by two
percent by 2030 and by ten percent by 2070 at the
90th percentile, based on CSIRO modelling, shown
in Table 4.1.
This represents the worst case scenario. By 2070
UV is predicted to be more like that currently
experienced by Sydney based on data from BOM
(BOM) and CSIRO (CSIRO, 2007 a) with an increase
from 6 to 6.3.
Table 6.13: Summary of Radiation Risks by Asset Type
Consequences
Actions
Risk
Road Surfacing
Increased radiation will accelerate
the rate at which bituminous surfaces
became brittle due to oxidation, thus
requiring more frequent resurfacing.
Investigate most efficient way
to manage surface materials to
adapt to future UV levels.
Significant
Pavement Structure
No significant consequences
No action required.
Insignificant
Drainage
More intense rainfall could result in
No action required.
localised flooding, damage due to scour,
less safe running conditions for traffic
during rainstorms on wide flat pavements.
Insignificant
Roadsides
Higher levels of UV radiation may cause
more rapid deterioration of items such as
plastics materials used in road furniture,
and the reflective faces of signs
No action required at this
stage.
Important
Structures
No significant consequences
No action required.
Insignificant
ITS/Electrical Assets
Some plastic or perspex housings or
casing may require replacement or
redesign.
No action required at this
stage.
Important
Operations
No significant consequences
No action required.
Insignificant
CLIMATE CHANGE RISK ASSESSMENT
29
6.6 Prioritising Risks
In order to better focus VicRoads actions these
identified risks have been prioritised, on the
basis of the assessed level of risk, the design life
of the assets and also the estimated time until
changes in climate would impact on the assets
performance in the road network (refer Table 6.14).
All significant risks have been identified as priorities.
In addition, whilst the impact on drainage was
assessed as “important”, it has also been classified
as a prioritised risk because the stormwater
drainage is an asset with a long design life and the
impacts are likely to be experienced in the short
to medium term. Another example is the impact
on roadsides impacted by storm surge and sea
level rise. This was assessed as “important”, but has
been prioritised as it is an integral part of the road
network in areas caused by sea level rise.
Of all the risks assessed only sea level rise and
elements of rainfall, radiation and temperature
were considered to be significant risks to the road
network. Changes in projected climatic parameters
will, however, also have benefits for the road
network, such as:
zz a decreased likelihood of black ice on Victorian
roads through increased average overnight
temperatures
zz less operational impacts to the road network
from snow, which will also result in less salt
impact to the local environment
zz a likely increase in the life of the structural
pavement component of the road due to
higher temperatures and decreased humidity
levels leading to drier subgrades and pavement
structural layers
zz a decrease in the annual rainfall (particularly in
Spring) will lengthen the available road sealing
season, as well as the annual road construction
window. However, this is likely to be offset by
construction disruption from increased summer
temperatures and heatwaves
zz a possible decrease in the amount of
contingency in contracts for inclement weather.
Nonetheless, all risks will continue to be monitored
and assessed as new information and asset
monitoring data becomes available.
30
Table 6.14 Summary of Prioritised Risks and the Impacts of Climate Change on Assets and Customers
Climate Parameter
Asset Type
Impact on Asset
Impact on Road User
Sea Level Rise
Road Pavement
Higher impact from storm surges and
permanent inundation of coastal road
assets including pavements.
Reduced availability due
to road closures from
storm surge events and
sea level rise.
Road Surfacing Layers
Drainage
Roadside
Structures
ITS/Electrical Assets
VicRoads Activities
Rainfall
Drainage
Potential for widespread damage to all road
infrastructure including pavements and
structures, due to rising sea levels, resulting
in flooding and road closures. Flooding
may also occur during rain storms in areas
where drainage efficiency is affected by
reduced fall to outlet.
Increased incidence of intense rainfall
could result in localised flooding, increased
stress on drainage systems, damage due
to scour, less safe running conditions
for traffic during rainstorms on wide
flat pavements. In addition to localised
scouring of roadsides and bridge structures
this would increase the risk of landslides.
Increased risk of
aquaplaning especially
on wide flat surfaces
and localised network
operational issues due to
flooding.
The decrease in annual rainfall and
rainy days combined with increased
temperatures and increased
evapotranspiration will lead to degraded
roadsides especially remnant and
landscaped roadsides. This is turn will lead
to increased incidence of weeds and other
invasion species.
Decreased amenity of the
journey whilst improving
driving conditions.
Radiation
Road Surfacing Layers
The increased level of UV could contribute
to the increased rate of pavement oxidation
and result in a shorter expected life of
the pavement surface, especially for a
spray seal surface. Potential for increased
maintenance costs
Reduced availability due
to increased road closure
for maintenance.
Temperature
Roadsides
Increased in average temperature will
lead to reduction in black ice incident and
snowfall but would lead to a decrease
in the life of some electrical assets,
particularly LED lights.
Decreased accidents from
poor driving conditions.
Improved travel times.
Increase in frequency of warm nights
will increase heat retention further
exacerbating the heat island effect.
Increase in frequency of very hot days
and lower rainfall will result in the loss
of many plant species and less vigorous
growth of many of the plant survivors. This
could result in greater erosion, landslips,
increased fire risk, issues with management
of pest plants and animals and loss of
landscape amenity.
Reduced availability
due to road closures for
maintenance.
It will also increase the stress on expansion
joints on bridges and lead to softening and
deformation of spray seal roads
Decreased amenity of the
journey.
Derived from (UK Highways Agency, 2011)
CLIMATE CHANGE RISK ASSESSMENT
31
7. Developing Adaptation
Responses
Whilst specific adaptation responses will be
progressively developed, an amount of research
and discussion has already occurred regarding
possible approaches to adaptation and these are
discussed in more detail below. In addition, it is
recognised that a key component of adaptation
includes the “soft systems” such as the ability to
generate, access and interpret information about
climate change and its likely impacts; suitable
methods for identifying and assessing potential
adaptation strategies; appropriately skilled people;
adequate financial resources; strategic planning and
governance systems that will embrace adaptation
planning; and above all, a willingness to adapt.
As such, inter-disciplinary and inter-agency studies
will be important requiring engagement with all
stakeholders in order to build resilience and reduce
vulnerability to climate change.
7.1 Sea Level Rise
Given the discussion in section 6.1, it is clear sea
level rise will affect all asset types in those locations
impacted. In some instances, it may be possible to
rebuild affected roads, within the current reserve, at
a higher level, and where this is not possible, other
adaptation responses will be necessary. An example
of this would be realigning the road further from
the coast. However, this would be a significant
undertaking with potential for significant impacts on
local communities, other infrastructure and cultural
and biodiversity values as a minimum, with significant
implications for some land owners and developers.
Infrastructure associated with housing, industry and
agriculture is also likely to be affected by sea level
rise and therefore any change to road infrastructure
will need to be considered in association with other
related industries and activities.
32
Sections of the South Gippsland Highway along the
north end of Westernport Bay between Tooradin
and Koo Wee Rup have been identified as being
at risk of inundation and sea level rise within 50
years. This road is a major tourist route, important
regional access arterial and major transport route.
Some of the properties and local agriculture served
by this road may need to be relocated to higher
ground. The highway itself could be raised in situ,
but the most appropriate route for a flood proof
facility may involve the development of a new
road on a new alignment, in coordination with the
relocation of other community infrastructure and
industrial/commercial/agricultural activity.
Sea level rise will also need to be taken into account
in the planning of new residential and infrastructure
developments in coastal areas. Consideration of sea
level rise is already affecting the conditions imposed
on approved development proposals for both new
and existing coastal properties. As a potential referral
authority as well as a proponent, a documented
rational approach showing how climate change
risk such as sea level rise is being considered and
managed on the main road network will aid decision
making across Government.
Early estimates of the costs of responding to sea
level rise through relocation of road assets indicate
significant expenditure over multiple years will be
required based on a 0.8 m sea level rise. This is
based on currently available data sources and needs
refining at an early stage to be able to provide advice
to government of the risks of sea level rise.
Consultative links need to be developed
with relevant government departments, local
government and agencies to ensure the response
to sea level rise is rational and consistent and able
to be managed appropriately, including information
to affected sections of the community.
The effects of sea level rise will initially be exhibited
through local drainage issues and coastal erosion.
Accordingly, investigation of sites vulnerable
to these issues should have a high priority for
investigation. However, investigation of long term
effects will also need to be completed before an
appropriate assessment can be made of the most
cost-effective economic solution.
Summary of Sea Level Rise Actions
A number of actions will need further investigation including;
§§
confirming the projected sea level rise and storm surge impacts through ongoing review and
consultation
§§
confirming cost estimates for predicted impacts
§§
developing special bridge standards for flood prone areas
§§
identifying appropriate protective measures and situations where they should be considered
§§
consulting with State government departments, catchment authorities and local government
regarding the options for rebuilding or realigning affected routes to protect for sea level rise and
projected storm surge
§§
undertaking a case study to gain further insights into climate adaptation.
Edithvale Road has been identified as a location at risk of sea level rise and storm surge. Given
it is a well established location with assets belonging to Melbourne Water, Kingston Council
and VicRoads, it is being developed as a case study of how adaptation can work with multiple
stakeholders. The case study will identify what adaptation would best suit the locations and
stakeholder needs. It will also aim to examine the likely timeframes for adaptation in this location.
The figure below shows the projected extent of sea level rise based on DEPI Future Coasts
projections to 2100, with storm surge impacting the area more widely.
CLIMATE CHANGE RISK ASSESSMENT
33
7.2 Temperature
Vegetation has been shown to have strong links
to the community’s sense of place (Kendall, 2011).
Plane trees are an example of this in the City of
Melbourne and are currently one of the most
prominent tree types (City of Melbourne, 2015).
They are also susceptible to leaf burn on hot days
(Nicholson, 2014), which can lead to distress and in
some cases tree death. A number of roadsides and
established urban tree species across Victoria were
adversely impacted by the Millennium drought,
however, it is understood that soil, water availability,
microclimate and topography will also influence
vegetation health. Broadleaf deciduous trees may
be less successful in future climates than narrow
leaved, evergreen trees which may be at less risk
(Kendal & McDonnell, 2014). Other species, such
as golden wattle, are less susceptible as they have
vertically oriented phyllodes, which minimise the
amount of direct sun exposure (Australian Plants
Society, 2011).
To assist in better identifying and quantifying areas
of risk, VicRoads will investigate species likely
to be at risk, as well as identifying replacement
species that are better suited to expected future
climate characteristics in roadsides. This will
include locations with existing geotechnical risks,
particularly if the existing vegetation is susceptible
to climatic changes, where a lack of action may
cause an increase in the risks of landslip.
The urban heat island effect is a temperature
related impact on the public in areas with
significant amounts of built infrastructure. Asphalt
roads contribute to the effect through both
their dark colour and the tonnages of materials
within the constructed roads and this is expected
to be exacerbated by increases in night time
temperatures. Further work will be undertaken to
understand the specific contribution of the main
road network to the urban heat island effect and
develop responses as appropriate.
34
Summary of Temperature Responses
A number of actions will need further
investigation including;
§
determining ‘at risk’ species through
literature, monitoring and anecdotal sources
§
determining options for replacement of
vegetation species on roadsides, which are
better suited to the expected climate
§
investigating opportunities for increasing
soil water availability including the use of
stormwater in watering roadside vegetation
§
ensuring data relating to the location
and frequency of road closures due to
temperature softening of pavements is
captured
§
investigating the relationships between
landslips and the vegetation condition of
roadsides
§
investigating the contribution of the main
road network and urban vegetation to the
urban heat island effect and options for
mitigation
7.3 Rainfall
Updated rainfall intensity, frequency, duration (IFD)
projection data has now been released as part of a
larger rainfall and intensity project undertaken by the
Bureau of Meteorology. The updated IFD data now
includes information from 1983 to 2012 in its dataset,
as well as addition stations measuring rainfall.
Figure 7.1 displays an estimation of the percentage
change when comparing this revised data to the
existing IFD data for the typical road drainage
design event (10% AEP of 10 minute duration).
The main observation is a 10-20% increase in the
intensity across the south eastern suburbs for this
type of event.
One of the asset types likely to be impacted
by more intense rainfall events is pavements,
particularly wide flat pavements and roads
with narrow shoulders. In most cases, it is not
practicable to alter existing pavements (such
as increasing crossfall) to reduce the likelihood
of a flow depth that could lead to aquaplaning
conditions; nor is it generally practicable to
alter the flow capacity of shoulders and kerbing.
Consideration may instead be given to applying
lower speed limits, temporarily closing lanes and/or
warning signs during heavy rain conditions, with the
aim of altering driver behaviour in the long term.
Summary of Rainfall Responses
A number of actions will need further
investigation including;
§§
reviewing the updated IFD information
once released and determine implications
for road design and site management
during construction
§§
developing technologies which allow
automatic detection and communication
of flooding on managed motorways
§§
investigating options to decrease the
potential for aquaplaning at locations
identified as being at risk
§§
ensuring operational personnel are aware
of the likely changes in rainfall intensity
and the importance of ensuring drain
cleaning is consistently undertaken
Percent Change: 10min, 10% AEP (estimated)
The other asset types likely to be impacted by
changes in rainfall intensity and volume are the
underground drainage systems, and structures
with pumped drainage. This means there will be
an increased importance on the maintenance of
existing assets to ensure the efficient operation of
underground drainage systems.
Figure 7.1 Estimated Changes in Rainfall Intensity for Typical
VicRoads Drainage Source from Bureau of Meteorology
CLIMATE CHANGE RISK ASSESSMENT
35
7.4 UV Level
7.5 Long Term Asset Responses
Increased UV radiation will accelerate the rate at
which bituminous surfaces became brittle due to
oxidation, thus requiring more frequent resurfacing.
VicRoads will investigate whether or not the use
of alternative bitumen products such as polymer
modified binders will improve the whole of life
effectiveness. Increased UV levels will also have
impacts on the design life of assets such as perspex
noise wall panels, roadside furniture and reflective
coatings on signage.
Whilst there are forecast impacts to different asset
classes through time, the appropriate approach is
primarily guided by the likely lifespan of the assets.
For assets with short life spans (e.g. ITS), or periodic
replacement requirements (e.g. pavement surfacing)
adaptation measures will be implemented as a
running change at an appropriate point in time.
However, a number of assets have significant lifetimes
as shown in Figure 5.1, particularly structural assets
such as bridges. In this case, adaptation measures will
need to be built into the construction requirements of
future assets.
Summary of UV Responses
A number of actions will need further
investigation including;
§
the use of polymer modified binders as a
cost effective treatment in road surfacing
applications in specific locations
§
establishing systems to collect performance
data to assess any changes in condition of
perspex noise panels or spray seals, which
might indicate a shortening of their life
Existing assets can be expensive to alter significantly
during their lives. As such, a set of responses
will be needed to manage their lifecycle. This is
independent of one off events or trigger points
which can impact on roads (i.e. sea level rise or
flood), where a separate set of responses is required.
Many existing assets have sufficient residual life such
that they will be impacted by climate change before
they reach the end of their operational lives.
Additionally there will need to be consideration as to
how these assets are impacted by climate change;
such as the resleeving and cathodic protection of
bridge structures such as the Phillip Island Bridge.
Sea level rise and increased heights of splash zone
will need to be factored into an activity of this type.
Accordingly, typical response options to mitigate
or avoid climate change impacts on existing assets,
in principle, include:
zz Undertake cost effective/appropriate/feasible
alterations at some trigger point in the future
(for example, undertake planned servicing/
rehabilitation with more resilient materials
(at a higher cost);
zz Adopt a more intensive maintenance schedule
(at a higher cost) to preserve level of service/
maintain serviceable lifespan; and
zz Accept lower level of service and/or shorter life
to replacement/refurbishment.
Summary of Long Term Asset Responses
A number of actions will need further
investigation including;
36
§
developing appropriate adaptation measures
to be built into the design of new assets
§
developing guidance or a decision making
framework and criteria for the improvement,
upgrade or replacement of assets
§
evaluating the whole of life costs of
adaptation response options for existing
assets such as bridges
7.6 Organisational Responses
There are also a number of adaptation responses
around organisational and data collection
opportunities which are not specific to any specific
type of asset or climatic parameter but need to
be investigated to provide baseline information
from which VicRoads, in collaboration with key
stakeholders, can make more informed decisions
regarding climate change adaptation measures.
These include:
zz developing baseline information on network
impacts from climatic parameters, to better
understand how any observed climate changes
impact on the performance of the road network
over the medium to long term. Examples of this
are road condition monitoring and data on road
closure duration, frequency and location
zz ensuring that climate adaptation is considered
in relation to the development and updating
of other VicRoads strategies, for example the
VicRoads Asset Strategy and the VicRoads Rural
Arterial Roads Strategy
zz standardising the integration of adaptation data
layers such as sea level rise and storm surge
into network planning activities to identify likely
risks early in the development of an alignment.
This could have the benefit of allowing climate
risks to be avoided rather than including costly
adaptation measures at a future point in time
zz embedding a level of awareness in VicRoads
across the organisation. This will assist
employees to understand the likely types
of impacts, understanding how VicRoads is
addressing these risks and also assist employees
in discussions with other stakeholders around
adaptation. Importantly this will also assist
employees required to assist in gathering data
and information to understand why they are
undertaking these actions
zz constantly reviewing risk and responses as
climate change projections are refined
zz collaborating with the National Committee
on Water Engineering of Engineers Australia
in the ongoing review of the IFD to ensure
that the design of new works will be able to
accommodate the changes in rainfall patterns
associated with climate change.
zz the development of information and guidance
for identified knowledge gaps necessary to
more accurately understand climate change
risks and impacts. These areas include, but
are not limited to:
§§ impact of fire on road pavements
§§ contribution of VicRoads Assets to UHI effect
and potential treatments
§§ whether any areas in Victoria are susceptible
to salt related pavement blistering or salinity
related impacts
§§ changes in the distribution of flora and fauna
§§ alternative water sources
§§ geotechnical risk (including coastal erosion)
zz continuing to review potential risks and
responses as a result of:
§§ economic changes namely population
growth and urban planning.
§§ changes in the road network and innovations
in smart car technologies, driverless cars,
smart cities and other supporting infrastructure
§§ understanding community expectations
with respect to level of service and how the
level of impacts acceptable for road users
and freight will increase or decrease as more
impacts occur
zz reviewing financial implications including:
§§ how adaptation will be funded, given
the likely broad impacts on society and
infrastructure resulting in competing needs
for the same funding.
§§ implications for insurance and whether
insurance policies could be changed to
incentivise adaptation or penalise a lack
of adaptation
Summary of Organisational Responses
A number of actions will need further investigation including;
§§
Ensuring appropriate existing sources of information are captured to provide baseline
and contextual information for climate change impacts and to inform adaptation
§§
Developing a level of internal awareness of climate change risks to VicRoads and how
this is being addressed.
§§
Ensuring that climate adaptation is integrated as appropriate into other new or revised
VicRoads strategies to ensure appropriate consideration of responses
§§
Developing and integrating appropriate climate risk data layers to ensure a consistent
evaluation of forecast climate change impacts into strategic network planning activities
CLIMATE CHANGE RISK ASSESSMENT
37
8. Next Steps
A climate resistant road network will reduce
the physical vulnerability of critical infrastructure
through the retrofitting and rehabilitation of existing
infrastructure including associated drainage and
flood mitigation systems in order to strengthen its
resilience to natural hazards and the anticipated
impacts of climate change.
Developing resilience and building adaptive
capacity of road networks, especially in regards
to climate change, is integral to accessing and
delivering critical infrastructure. Over time,
state and national infrastructure has become
increasingly interconnected and interdependent,
with a particular reliance upon transportation
systems, so failures or loss of transport services
will have subsequent effects. Any damage to
road infrastructure from climate change and
extreme weather can have an impact on local
communities and businesses. Restrictions on
the movement of people, goods and supplies
around a region will almost certainly lead to
impacts upon the local economy, environment
and the health and wellbeing of residents. Given
these interdependencies within and between
infrastructure sectors, it is essential that these
interdependencies are both understood and
managed to improve the resilience of infrastructure
to future climate change.
Ongoing monitoring and review of climate
change risk, vulnerabilities and the effectiveness of
adaptation response is essential. According to the
United Nations Framework Convention on Climate
Change (UNFCC).
Monitoring and evaluation of projects, policies
and programmes forms an important part of
the adaptation process. Ultimately, successful
adaptation will be measured by how well
different measures contribute to effectively
reducing vulnerability and building resilience.
Lessons learned, good practices, gaps and
needs identified during the monitoring and
evaluation of going and completed projects,
policies and programme will inform future
measures, creating an iterative and evolutionary
adaptation process.
38
Given the timeframes of projected climate
change impacts, VicRoads has time to revise its
climate change adaptation responses as updated
information becomes available. The exceptions are
the need for early integration of climate change
implications into the selection of road corridors
and the design of bridges given their long design
life and the difficulty in adapting existing bridges. In
addition, these climate change impacts, including
those beyond 2100 are important to understand as
part of current strategic network planning activities.
The creation of road reservations (such as the E6
transport corridor) can be in place for a significant
amount of time before construction. It is therefore
important to consider climate change impacts as
part of the creation of road reservations, especially
along coast so road networks are developed away
from areas of risk.
The projected climatic changes will almost certainly
have a significant impact on the appraisal, design,
construction, operation and maintenance of
road infrastructure. The risk assessment process
described herein enables climate change to be
regarded as a strategic risk to which requires
consideration and adoption of adaptation principles
to address the climate-induced impacts.
VicRoads recognises that for adaptation measures
to be successful, it will need to incorporate
involvement from a number of stakeholders such
as local councils, catchment authorities and
other government departments who would likely
be affected or who would be involved in a coordinated response. Not only will this facilitate early
engagement but should minimise any duplication
of effort or maladaptation. Forward planning
will enable VicRoads in partnership with its key
stakeholders - to make investment decisions at the
right time, making sure that it continues to provide
the levels of service that its stakeholders and
network users expect, both now and in the future.
Glossary
AEP
Annual Exceedence Probability is the probability of
a given volume of rainfall being exceeded in year
(i.e. a 20% AEP of 100mm is a probability of 20%
that the annual rainfall will exceed 100mm). 100
divided by the AEP will give a rough indication of
the length of time between annual rainfalls of a
given volume (i.e. 100/20 = 5 years between annual
rainfall volumes of 100mm).
Asphalt
a graded mixture of stones and finer particles
bound together with bitumen.
BOM
Bureau of Meteorology
CCTV
VicRoads maintains a network of Closed Circuit
Television Cameras at strategic locations on the
road network to help monitor and manage traffic
flow conditions
CSIRO
Commonwealth Scientific and Industrial Research
Organisation is an Australian Federal agency
performing scientific research
DEPI
is the former Department of Environment and
Primary Industry, a Victorian State Government
Department which managed Coasts & Marine,
Conservation & Environment, Fire & Other
Emergencies, Forests, Land Management, Parks
& Reserves, Plants & Animals, Property Titles &
Maps, Recreation & Tourism and Water
DEDJTR
is the Department of Economic Development,
Jobs, Transport and Resources, a Victorian State
Government Department.
DELWP
is the Department of Environment, Land, Water
and Planning, a Victorian State Government
Department.
DSE
Department of Sustainability and Environment a
former Victorian State Government Department,
which managed water resources, climate change,
bushfires, public land, forests and ecosystems. It is
now incorporated within DELWP.
IFD
or Intensity, Frequency, Duration is a commonly
used tool to graphically represent the projected
rainfall volumes for a rainfall event with
combination of rainfall intensity, event frequency
and event duration.
IPCC
The Intergovernmental Panel on Climate Change
is a global scientific body established by the United
Nations. It produced reports that support international
efforts to limit and manage climate change
LED
Light Emitting Diode, a technology used to provide
illumination (currently used primarily for traffic
lights, but may be extended to public street lighting)
that has a long service life and low operating costs
due to low power consumption
Main Road or Arterial Road
VicRoads is the co-ordinating road authority for
management of the declared freeways and arterial
roads listed in the Road Management Act 2004,
but excludes local roads under the care of local
government, forest roads under the care of the
Department of Environment and Primary Industry
and Toll Roads.
Roadside
generally refers to the area between the outer
edge of shoulder or kerbing and the road reserve
boundary that is usually grassed or planted. It
includes pedestrian and cycle paths.
Road Pavement
Road Pavement Layers are made up of compacted
layers of structural fill and crushed rock. The
purpose of the road pavement is to carry wheel
loads without deforming and causing damage to
the surface layers.
Road Surface
The majority of main roads in Victoria have a
waterproof layer of surface material to provide a
low maintenance all-weather riding surface and
protect the underlying road pavement material
from ingress of free water. Typically, this surface is
a sprayed seal in rural areas and an asphalt layer in
more heavily trafficked urban areas.
Sprayed Seal
a surface of stones embedded in a layer of bitumen.
CLIMATE CHANGE RISK ASSESSMENT
39
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CLIMATE CHANGE RISK ASSESSMENT
41
Appendices
Appendix 1 : Case Studies
Phillip Island Road – Climate Adaptation
Phillip Island Road is the only means of road access
to San Remo and Phillip Island, which has some of
Victoria’s iconic tourist locations and sporting events,
as well as a resident population of over 9000.
This provided an opportunity to work together and
deliver a positive outcome for both parties and
the community, and is planned to link with other
existing and future tracks in this area to enhance
the foreshore experience
42
DELWP
The adaption measure selected was a revetment,
which is a sloping structure designed to protect an
area and absorb the energy of incoming water. The
revetment was designed to be a non-overtopping
seawall with a lifespan of 100 years. The designed
rock revetment crest level of 3.91m AHD has been
calculated using the highest astronomical tide
for Stony Point (1.65m), the 1 in 100 storm surge
level (0.82m), sea level rise at 2100 (0.8m) and the
wave run up for rock armoured slopes (2:1) with an
impermeable core (0.64m). That is 1.65 + 0.82 +
0.8 + 0.64 = 3.91. In this way, the design life of the
revetment (and the stability of the slope behind it) is
maximised while mitigating the potential impacts of
climate change.
DELWP
In September 2012 an erosion event removed
about 3 metres of foreshore at San Remo adjacent
to the Phillip Island Rd, with the road now within
3-4 metres of the edge of the cliff and at risk of
collapse. The cliff in this vicinity is about 11 metres
in height.
Great Ocean Road – Adaptation Measure
Given the iconic nature and high proportion of
tourist traffic, the main challenge in implementing
the works was in communicating the closures of
the road and ensuring it occurred during a time
with lower projected traffic volumes.
DELWP
After consideration of likely parameters, with a
local projected rainfall projected to remain at
900-1100mm per year in 2050 (DEPI, 2014) and an
increased rainfall intensity of 6.5 percent in 2070,
it was decided to replace the existing 600mm
diameter drain was replaced with two 1.5metre
diameter drains, which are shown in photo below.
This will ensure that the culvert can deal with
projected volumes and increases to projected rainfall
intensities. Additional works included replacing
the concrete end walls, the existing fill material,
install kerb and channel and beaching to control
embankment erosion and installation of guard fence.
The completed works are shown below.
DELWP
The location prior to adaptation is shown in the
photo below. Whilst it was seen that the existing
drainage was undersize to requirements, the likely
future drainage needs were considered, including
the potential for more intense rainfall events as a
result of climate change.
DELWP
As part of current Great Ocean Road maintenance
works, drainage near approximately 1.5 kilometres
south west of Wye River, was identified as
needing replacement, due to age and damage as
stormwater was gathering on the upstream side
and infiltrating the embankment creating cavities
and weakening the strength of the embankment.
CLIMATE CHANGE RISK ASSESSMENT
43