Barwon Heads Bridgebarwonheadsassociation.com/files/Maunsell - Barwon... · 4. Climate change impacts on materials need to be considered in the design phase of the bridge to reduce

Barwon Heads Bridge

Climate Change Impacts VicRoads

September 2006

Barwon Heads Bridge Prepared for

VicRoads Prepared by Maunsell Australia Pty Ltd Level 9, 8 Exhibition Street, Melbourne VIC 3000, Australia T +61 3 9653 1234 F +61 3 9654 7117 www.maunsell.com ABN 20 093 846 925

September 2006 300 243 06

© Maunsell Australia Pty Ltd 2006 The information contained in this document produced by Maunsell Australia Pty Ltd is solely for the use of the Client identified on the cover sheet for the purpose of provision to the Barwon Heads Bridge Advisory Committee. Maunsell Australia Pty Ltd undertakes no duty to or accepts any responsibility to any third party who may rely upon this document. All rights reserved. No section or element of this document may be removed from this document, reproduced, electronically stored or transmitted in any form without the written permission of Maunsell Australia Pty Ltd

Barwon Heads Bridge T:\600 177 06 Barwon Heads Bridge\Task 1.06 - Climate Change Impacts\Barwon Heads_Climate Change Impact Introductory Report V2.doc Revision V1 September 2006

Quality Information Document Barwon Heads Bridge

Ref 300 243 06

Date September 2006

Prepared by Michael Nolan

Reviewed by Greg Harrison - Acting Group Manager

Barwon Heads Bridge Planning Study

Revision History

Authorised Revision Revision

Date Details Name/Position Signature

V1 13/09/2006 Draft Report – Independent Advisory Committee Hearing

Greg Harrison Acting Group Manager

V2 20/09/2006 Final Report – Independent Advisory Committee Hearing



Table of Contents 1.0 Summary 1

1.1 Instructions 1 1.2 Structure of the Report 1 1.3 Findings 1


1.0 Summary 1.1 Instructions Maunsell was approached by VicRoads in July 2006 to assist the Independent Advisory Committee convened to consider the options for the Barwon Heads Bridge. Maunsell and Cardno Lawson Treloar were engaged to provide expert opinion on the concerns raised by the Department of Sustainability and Environment in relation to erosion of the Ocean Grove Spit and western bank of the Barwon River as it relates to the proposed Barwon Heads Bridge redevelopment. Principally there were two areas of concern to be further investigated, they were: • Climate Change Impacts on the stability of the Ocean Grove Spit and River Flows; • Hydraulic impacts of the proposed upgrades to the Barwon Heads Bridge under existing

conditions. • Climate Change Impacts on the proposed upgrades to the Barwon Heads Bridge; and

1.2 Structure of the Report Two separate reports have been developed detailing the relevant investigation and findings for each area of concern. The title and author of each report is listed below. • Barwon Bridge – Impact of Climate Change Report RM2132 (Cardno Lawson Treloar) ; and • Barwon Bridge – Climate Change Impacts (Maunsell Australia Pty Ltd). The two reports are attached.

1.3 Findings The position of the shoreline on the Ocean Grove Spit is governed by parameters other than sea level, in particular the dominant wave direction and supply of sediment from the west. It is very unlikely that these will change in a manner which would lead to a change in the average position of the shoreline on the Spit. There may be a slight increase in the short-term movement of the shoreline if strong south-east storms increase in frequency, however the average position will not vary.

The calculations indicate that the proposed bridge options do not have any impact on the hydraulics of the estuary. It is also shown that both the existing structure and the proposed options will not become unserviceable from a hydraulic point of view under the climate change scenarios considered.

The key climate change assessment findings and recommendation were:

1. The Ocean Grove Spit is expected to remain relatively stable under future climate change impact scenarios.

2. Any bridge option which is of a deck height similar to the existing bridge is unlikely to be impacted by an increased intensity of extreme rainfall events from climate change.

3. The western bank of the Barwon River is not likely to be eroded by increased tidal and river flood levels.

4. Climate change impacts on materials need to be considered in the design phase of the bridge to reduce the risk of climate change accelerating degradation of the bridge asset over time.

Barwon Heads Bridge T:\600 177 06 Barwon Heads Bridge\Task 1.06 - Climate Change Impacts\Barwon Heads_Climate Change Impact Introductory Report V2.doc Revision V1 September 2006 Page 1

Recommendation 1. Vic Roads specify the inclusion of climate change considerations as part of the design standards used and materials specified in the design phase of the Barwon Heads Bridge be selected to avoid any accelerated degradation of the bridge asset over time.

Climate change does not pose a significant threat to the Barwon Heads Bridge development because of its position in relation to the Barwon Bluff; the protection from the prevailing wind and swell directions; the expectation that the equilibrium of the Ocean Grove Spit will continue; the nature of the Barwon River catchment’s capacity to reduce the impact downstream of extreme rainfall events; and the height of the existing bridge to cope with increased magnitude of river and tidal flood events. Climate change considerations need to be included in the design phase of the bridge to avoid any accelerated physical degradation of the bridge asset over time.

Barwon Heads Bridge T:\600 177 06 Barwon Heads Bridge\Task 1.06 - Climate Change Impacts\Barwon Heads_Climate Change Impact Introductory Report V2.doc Revision V1 September 2006 Page 2

Barwon Bridge - Climate Change Impacts Independent Advisory Committee Hearing

Expert Witness Statement - Michael Nolan VicRoads

September 2006

Independent Advisory Committee Hearing Prepared for

VicRoads Prepared by Maunsell Australia Pty Ltd Level 9, 8 Exhibition Street, Melbourne VIC 3000, Australia T +61 3 9653 1234 F +61 3 9654 7117 www.maunsell.com ABN 20 093 846 925

September 2006 300 243 06

© Maunsell Australia Pty Ltd 2006 The information contained in this document produced by Maunsell Australia Pty Ltd is solely for the use of the Client identified on the cover sheet for the purpose of provision to the Barwon Heads Bridge Advisory Committee. Maunsell Australia Pty Ltd undertakes no duty to or accepts any responsibility to any third party who may rely upon this document. All rights reserved. No section or element of this document may be removed from this document, reproduced, electronically stored or transmitted in any form without the written permission of Maunsell Australia Pty Ltd

Barwon Bridge - Climate Change Impacts Independent Advisory Committee Hearing T:\600 177 06 Barwon Heads Bridge\Task 1.06 - Climate Change Impacts\Barwon Heads_Expert Witness StatementClimateV2.doc Revision V1 September 2006

Quality Information Document Independent Advisory Committee Hearing

Ref 300 243 06

Date September 2006

Prepared by Michael Nolan

Reviewed by Greg Harrison - Acting Group Manager

Barwon Heads Bridge Planning Study

Revision History

Authorised Revision Revision

Date Details Name/Position Signature

V1 14/09/2006 Draft Report – Independent Advisory Committee Hearing


V2 20/09/06 Final Report – Independent Advisory Committee Hearing



Table of Contents 1.0 Introduction 1

1.1 Name and Qualifications 1 1.2 Instructions and Information 1 1.3 Project Involvement 2

2.0 Climate Change Impact Summary 3 3.0 Climate Change Considerations 4

3.1 Future Climate Change 4 3.2 Observed Climate Change 4 3.3 Intergovernmental Panel on Climate Change Scenarios 4 3.4 Projecting Changes in Victorian Climate 5

4.0 Climate Change Variables and Potential Impacts 7 4.1 Sea-Level Rise Impacts 7 4.2 Extreme Wind-Speed 8 4.3 Extreme Daily Rainfall 8 4.4 Other Climate Change Impacts on the bridge 9

4.4.1 Average Maximum Temperature 9 4.4.2 Extreme Daily Temperatures 9 4.4.3 Relative Humidity 9 4.4.4 Impacts on Materials from Temperature and Humidity 10

5.0 Conclusion 11 6.0 Selected Resources 12 7.0 References 13 Appendix A Curriculum Vitae a Appendix B CCAM Mark 2 Climate Model Projections b


1.0 Introduction Maunsell is pleased to provide expert opinion on the concerns raised by the Department of Sustainability and Environment in relation to the erosion of the Ocean Grove Spit and the western bank of the Barwon River as it relates to the proposed Barwon Heads Bridge redevelopment.

1.1 Name and Qualifications My name is Michael Christian Nolan, and I practice as a Sustainability Consultant. I hold the position of Senior Sustainability Consultant at Maunsell Australia Pty Ltd (Maunsell), Level 9, 8 Exhibition Street, Melbourne. I have been employed by Maunsell since 2004. I hold the following academic qualifications: • Bachelor of Applied Science (Environmental Resource Management), 2001 (Southern Cross

University); • Certificate IV Environmental Change Management, 1997 (Connect); and • Certificate IV Business management, 2002 (Box Hill TAFE). I hold the following professional affiliations: • Member, Environment Institute of Australia and New Zealand; and • Member, Victorian Planning and Environmental Law Association. I have over twelve years experience in the environmental management and sustainability fields, focusing in the last two years on climate change impacts on infrastructure projects in conjunction with CSIRO Climate and CSIRO Marine and Atmospheric Research. My professional experience includes work as a Sustainability Consultant with Maunsell, Sustainable Change and Terra Nova Environmental Strategies, as a Strategic Planner (Sustainability) with RMIT University and as an Environment Officer for both La Trobe University and the National Union of Students. A copy of my curriculum vitae is provided in Appendix A.

1.2 Instructions and Information This report has been prepared at the instruction of VicRoads to assist the Independent Advisory Committee convened to consider the options for the Barwon Heads Bridge. I have been instructed by Louise Hicks of Phillips Fox, on behalf of VicRoads, to prepare the following report. In preparing this report I have undertaken the following: • Reviewed existing studies on climate change and the impact on infrastructure, in particular recent

work by Maunsell; • Reviewed previous coastal engineering reports commissioned by Barwon Coast Committee of

Management examining erosion and accretion at the tip of the Ocean Grove spit; • Reviewed the “Victorian Coastal Vulnerability Study” (Port of Melbourne Authority, 1992) as it

relates to the Ocean Grove spit; • Reviewed climate change scenarios for extreme rainfall events and flood tide conditions that

would potentially impact at the height of the existing bridge structures; • Collaborated with Cardno Lawson Treloar in the review of the bridge options regarding impacts of

coastal processes to integrate climate change considerations; • Provided comments and recommendations to highlight possible mitigations of climate change

risk;

Barwon Bridge - Climate Change Impacts Independent Advisory Committee Hearing T:\600 177 06 Barwon Heads Bridge\Task 1.06 - Climate Change Impacts\Barwon Heads_Expert Witness StatementClimateV2.doc Revision V1 September 2006 Page 1

• Carried out an inspection of the site with particular attention to the issues raised by the Department of Sustainability and Environment submission; and

• Prepared this report to identify likely impacts of climate change on the Ocean Grove spit. The report is based on readily available existing information and doesn’t include significant new research.

I will appear before the Independent Advisory Committee to answer any questions relating to my report. I adopt this report as a true expression of my professional opinions and beliefs in this matter.

1.3 Project Involvement My involvement with the Barwon Heads Bridge Planning Study has included: • Project management of the Climate Change Assessment Study; • Integration of study findings with David Provis from Cardno Lawson Treloar; and • Appearance before the Independent Advisory Committee to answer questions regarding the

climate change implications for the bridge redevelopment.


2.0 Climate Change Impact Summary The summary of the climate change impacts on the Barwon Heads Bridge in provided in Table 2-1 below. The findings are explored in Section 4 of this report.

Table 2-1: Summary of Climate Change Impacts

Climate Variable Climate Change Impact

Potential Impact Findings

Sea-level rise:

2030: +3 to +17cm 2070: +7 to +52cm 2100: +9 to +88cm

Extreme wind-speed

2030: -3 to +3% 2070:: -3 to +6%

Extreme daily rainfall

2030: -4 to +12% 2070: -18 to +28%

1. Increased storm surge causing extensive erosion, leading to the instability of the Ocean Grove Spit.

2. Increased tidal and river flood levels impacting on bridge structural stability. To be considered for bridge options.

3. Increased tidal and river flood levels leading to extensive erosion and instability of the western bank of the Barwon River.

1. The Ocean Grove Spit is expected to remain relatively stable under future climate change impact scenarios.

2. Any bridge option which is of a deck height similar to the existing bridge is unlikely to be impacted by an increased intensity of extreme rainfall events from climate change.

3. The western bank of the Barwon River is not likely to be eroded by increased tidal and river flood levels.

Average maximum temperature

2030: +0.5 to +1.5°C 2070: +1.0 to +5.0°C

Extreme daily temperatures

2030: +10 to +60% 2070: +20 to +100%

Relative humidity

2030: +0 to +3% 2070: +0 to +7%

4. Accelerated degradation of materials and structural condition leading to reduced life expectancy of the bridge asset.

4. Climate change impacts on materials need to be considered in the design phase of the bridge to reduce the risk of climate change accelerating degradation of the bridge asset over time.

RECOMMENDATION 1.

Vic Roads specify the inclusion of climate change considerations as part of the design standards used and materials specified in the design phase of the Barwon Heads Bridge be selected to avoid any accelerated degradation of the bridge asset over time.


3.0 Climate Change Considerations 3.1 Future Climate Change To estimate future climate change, scientists have developed greenhouse gas and aerosol emission scenarios. These are based on various assumptions about economic growth, human behaviour and technological change and are therefore not predictions of what will actually happen. This study uses scenarios developed by the Intergovernmental Panel on Climate Change (IPCC, 2001), which are described in the Special Report on Emission Scenarios (SRES, 2000). These scenarios assume “business as usual” without explicit policies to limit greenhouse gas emissions, although some scenarios include other environmental policies that indirectly affect greenhouse gases, e.g. policies to reduce air pollution.

3.2 Observed Climate Change The Earth has warmed by about 0.7°C on average since the year 1900 (Jones and Moberg, 2003). Most of the warming since 1950 is due to human activities that have increased atmospheric concentrations of greenhouse gases (IPCC, 2001). There has been an increase in heatwaves, fewer frosts, warming of the lower atmosphere and upper ocean, retreat of glaciers and sea-ice, a rise in sea-level of about 15 cm, acidification of the oceans and increased heavy rainfall in many regions (Alexander et al., 2005; Fu et al., 2004; Pelejero et al., 2005). Many species of plants and animals have changed their location or the timing of their seasonal responses in ways that provide further evidence of global warming (Hughes, 2003). Australia’s average temperature has risen by almost 0.9°C from 1910–2004 (Nicholls and Collins, 2005). Most of this increase occurred after 1950. It is likely that a significant contribution to the warming is due to increases in greenhouse gases and aerosols (Karoly and Braganza, 2004).

3.3 Intergovernmental Panel on Climate Change Scenarios The IPCC (2001) attributes most of the global warming observed over the last 50 years to greenhouse gases released by human activities i.e. energy production from fossil fuels. To estimate future climate change, the IPCC (SRES, 2000) prepared forty greenhouse gas and sulfate aerosol emission scenarios for the 21st century that combine a variety of assumptions about demographic, economic and technological driving forces likely to influence such emissions in the future. They do not include the effects of measures to reduce greenhouse gas emissions, such as the Kyoto Protocol. Each scenario represents a variation within one of four 'storylines': A1, A2, B1 and B2. The experts who created the storylines (described below) were unable to arrive at a most likely scenario, and probabilities were not assigned to the storylines. • The A1 storyline describes a world of very rapid economic growth in which the population peaks

around 2050 and declines thereafter and there is rapid introduction of new and more efficient technologies. The three sub-groups of A1 are fossil fuel intensive (A1FI), non-fossil fuel using (A1T), and balanced across all energy sources (A1B);

• The A2 storyline depicts a world of regional self-reliance and preservation of local culture. In A2,

fertility patterns across regions converge slowly, leading to a steadily increasing population and per capita economic growth and technological change is slower and more fragmented slower than for the other storylines;

• The B1 storyline describes a convergent world with the same population as in A1, but with an

emphasis on global solutions to economic, social and environmental sustainability, including the introduction of clean, efficient technologies; and


• The B2 storyline places emphasis on local solutions to economic, social and environmental sustainability. The population increases more slowly than that in A2. Compared with A1 and B1, economic development is intermediate and less rapid, and technological change is more diverse.

The projected carbon dioxide and sulfate aerosol emissions, and carbon dioxide concentrations, are shown in Figure 1 (a, b, c). Emissions of other gases and other aerosols were included in the scenarios but are not shown in the figure. By incorporating these scenarios into computer models of the climate system, the IPCC (2001) estimated a global-average warming of 0.54 to 1.24°C by the year 2030 and 1.17 to 3.77°C by the year 2070 (Figure 1d). The analysis allowed for both uncertainty in projecting future greenhouse gas and aerosol concentrations (behavioural uncertainty) and uncertainty due to differences between models in their response to atmospheric changes (scientific uncertainty). Projected sea-level rise is shown in Figure 1e. The range of uncertainty in projections of global warming increases with time. Half of this range is due to uncertainty about human socio-economic behaviour, technological change and consequent emissions of greenhouse gases and sulfate aerosols. The other half of the range is due to different climate model responses to these scenarios of greenhouse gases and sulfate aerosols. Each of the models is considered equally reliable.

3.4 Projecting Changes in Victorian Climate Computer models of the climate system are the best tools available for simulating climate variability and change. These models include representations of the dynamical behaviour of the atmosphere, oceans, biosphere and polar regions. A detailed description of these models and their reliability can be found in IPCC (2001). The choice of climate simulations for this study was constrained by three factors:

1. Models that perform well over south-eastern Australia; 2. Availability of simulated data with fine resolution (grid-spacing of 50 km or less); and 3. Availability of simulated daily weather data from which to compute changes in daily extremes.

Assessments of the performance of 20 models over south-eastern Australia showed that 13 of the models adequately reproduced observed average patterns of temperature, rainfall and pressure (Hennessy et al., 2004; McInnes et al., 2005). Two of these models were appropriate for use in this study having a grid-spacing of about 50 km and daily data. These model simulations were performed with CSIRO’s “CCAM” model. These are called CCAM “Mark 2” global climate model and CCAM “Mark 3” global climate model. Their climate projections are considered independent. Both perform well over south-east Australia, although CCAM “Mark 2” has a better simulation of average temperature. Hence, slightly more confidence can be placed in results from CCAM “Mark 2”. Henceforth, CCAM “Mark 2” will be described as Mark 2. The scenarios are presented as a range rather than a single value of changes in conditions. The ranges incorporate quantifiable uncertainties associated with:

(i) the range of future emission scenarios; (ii) the range of global climate sensitivity (defined as the simulated global warming for a

doubling of carbon dioxide concentration); and (iii) model-to-model differences in the regional patterns of climate change.

The IPCC (2001) global warming scenarios incorporate (i) and (ii). The Mark 2 simulations provide information about (iii) but they are based on unique values of (i) and (ii) rather than the full range of uncertainty. We assume that there is a linear relationship between annual global mean warming and the regional mean climate response patterns (Whetton, 2001; Mitchell, 2003; Whetton et al., 2005). This allows us to extract regional patterns of climate change, per degree of global warming, from the Mark 2 simulations, then scale these patterns for the years 2030, 2070 and 2100, using the IPCC global warming values.


It is important to note that the conditions of any individual year will continue to be strongly affected by natural climatic variability and cannot be predicted.

Figure 1: (a) carbon dioxide (CO2) emissions for the six illustrative SRES (2000) scenarios, and the superseded IS92a scenario, (b) CO2 concentrations, (c) anthropogenic sulphur dioxide (SO2) emissions, (d) and (e) show the projected temperature and sea level responses, respectively. Source: IPCC(2001).

At present, it is not possible to assign probabilities to values within these ranges. However, the IPCC (2001) defined confidence levels that represent “the degree of belief among the authors in the validity of a conclusion, based on their collective expert judgment of observational evidence, modelling results and theory that they have examined”. The confidence levels are:

• Very high (95% or greater); • High (67-94%); • Medium (33-66%); • Low (5-32%); and • Very low (4% or less).

For the global warming data in Figure 1, “we have very high confidence that the lower warming limits will be exceeded and that the higher limits will not be exceeded”, IPCC (2001).

The climate change information used to support this study is limited by the information that was readily available at the time of the report. Ideally, the likely climate change impacts need to be not only researched but modelled specifically for a local area.


4.0 Climate Change Variables and Potential Impacts Several climate variables were selected to assess the likely impacts of climate change on the Ocean Grove Spit and Barwon Heads Bridge Options these include: • Sea-level rise; • Extreme daily rainfall; • Extreme wind-speed (99th percentile); • Average maximum temperature; • Extreme daily temperatures; and • Relative humidity. The likely changes were determined from existing data where available for 2030, 2070 and 2100. The following four potential climate change impacts were identified:

1. Increased storm surge causing extensive erosion, leading to the instability of the Ocean Grove Spit;

2. Increased tidal and river flood levels impacting on bridge structural stability thereby forming a consideration in determining bridge options;

3. Increased tidal and river flood levels leading to erosion and instability of the western bank of the Barwon River; and

4. Accelerated degradation of materials and structural integrity leading to reduced life expectancy of the bridge asset.

These four identified potential impacts are assessed in relation to relevant climate variables below.

4.1 Sea-Level Rise Impacts Global-average sea-level has risen 1.8mm ± 0.3 mm per year from 1950-2000 (Church et al., 2004). In future, sea-level is likely to continue rising due to thermal expansion of sea water, melting of land-based glaciers and melting of ice-sheets in Antarctica and Greenland (IPCC, 2001). Relative to the 1990 level, sea-level may rise 3 to 17 cm by 2030, 7 to 52 cm by 2070 and 9 to 88 cm by 2100 (Figure 1e). Estimates of future regional variations from the global-average rise are uncertain. A rise in sea-level due to climate change will increase the height and impact of the ‘once in a hundred years’ tidal flood event to the lower reaches of the Barwon River. This increase in height and impact of the extreme tidal flood was assessed because of the direct impacts on the bridge over the 100 year life expectancy of the bridge. The increase in tidal flood height is an estimate based on the medium upper limit of global-average sea-level rise for a selection of years. A summary of the estimated climate change tidal flood heights is provided in Table 4-3 below.

Table 4-1: Summary of Estimated Climate Change Tidal Flood Heights

No Climate Change Considerations With Climate Change Consideration Water level above

AHD1

Under Current Conditions (1990) 2030 2070 2100

Sea-level rise 0 12 45 70 1% tidal flood level 2.20m 2.32m 2.65m 2.90m


1Australian Height Datum (AHD) is a standard measure of local sea level, i.e. 0 AHD = sea level.

4.2 Extreme Wind-Speed Projected changes in extreme daily wind-speed were based on daily 99th percentile values (the highest 1% of events). Changes in the 99th percentile are shown in Appendix B Figure 3. The Mark 2 for the region around Barwon Heads in 2030 is expected to generally decrease by 0 to 3%, with the exception of winter whereby it increases by 0 to 3%. In 2070, the wind generally decreases by 3 to 6%, with the exception of winter where it increases by 0 to 3%. No extreme wind data for 2100 was available. Seasonal wind direction will be affected by climate change. The increase in intensity and frequency of extreme south easterly wind events combined with sea-level rise will increase the potential for the short term erosion of the Ocean Grove Spit, each event would be repaired by the expected increase in sand deposition. The potential for two extreme wind storm events to happen in a relatively quick succession and generating greater depth of erosion due to the Spit not having time to recover from the first event was considered. The size and positioning of the Spit as well as the expected increase in sand deposition suggests that this erosion would still only be temporary i.e. the bank quickly regenerates through longshore drift. The positioning is protected and therefore significantly less exposed to extreme wind events and storm surge. The erosion impacts on the Ocean Grove Spit from extreme wind events, storm surge and sea-level rise will be minimal because of the equilibrium of the spit location behind the Barwon Bluff will not change. It is presumed that the spit will experience an increase in sand deposition due to greater erosion impacts of climate change being experienced in less sheltered positions along the coast.

FINDING 1: The Ocean Grove Spit is expected to remain relatively stable under future climate change impact scenarios.

4.3 Extreme Daily Rainfall Under enhanced greenhouse conditions, increases in extreme rainfall are simulated in mid-latitudes where average rainfall increases, or decreases slightly (IPCC, 2001). For example, the intensity of the 1-in-20 year daily-rainfall event may increase by 5 to 70% by the year 2050 in Victoria (Whetton et al., 2002). An updated analysis for Victoria, based on the Mark 2 1-in-40 year events, confirms that increases in extreme daily rainfall are likely, but decreases are also possible in some regions and seasons. This analysis presented in Table 2 is for a mid-range emission scenario, rather than the full IPCC (2001) range. There are expected to be larger increases and smaller decreases in the year 2070 than in 2030. Decreases remain widespread in winter, but increases dominate in summer and autumn. No extreme daily rainfall data for 2100 was readily available during the development of this study.

Even though annual average rainfall is expected to decrease from greater frequency and severity of drought conditions, when extreme rainfall events do occur they are expected to be more intense in some seasons than previously experienced.

Table 2: CCAM (Mark 2) percent changes in South Central regional average intensity of 1-in-40-year daily rainfall, relative to the average simulated for 1961-2000 for 2030 and 2070 scenarios.

Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov2030 2070 2030 2070 2030 2070 2030 2070 +12% +11% = +28% -4% = -4% -18%

The potential for a extreme rainfall event increased by climate change was explored in the context of the deck height of the bridge. Based on the expert witness statement by David Provis from Cardno Lawson Treloar supplied as part of this report and the Corangamite Catchment Management Authority (2005) study on Barwon River Estuary Flood Study – Tidal Surge Analysis addressed, it is expected that the Barwon River flood levels under climate change conditions, even combined with tidal flood


levels will not be higher than the deck level of the existing bridge which varies from 3.6 m AHD to 4.4 m AHD. The nature of the catchment and the height of the bridge provides confidence that any of the bridge siting options will not be affected by extreme rainfall events.

FINDING 2: Any bridge option which is of a deck height similar to the existing bridge is unlikely to be impacted by an increased intensity of extreme rainfall events from climate change.

The position of the Barwon Bluff relative the western bank of the Barwon River provides protection from climate change impacts while the existing river wall protection provides further protection from erosion of the bank during extreme daily rainfall events. Sea-level rise, extreme wind-speed, storm surge and extreme daily rainfall is therefore, considered to have minimal erosion impact on the western bank of the Barwon River.

FINDING 3: The western bank of the Barwon River is not likely to be eroded by increased tidal and river flood levels.

4.4 Other Climate Change Impacts on the bridge Out of the other climate variables influenced by climate change it is important to note that increases in temperature and humidity could potentially influence the integrity of materials and structural features of the bridge(s). This is assessed below.

4.4.1 Average Maximum Temperature

Projected changes in annual and seasonal average maximum temperature are shown in Appendix B CCAM (Mark 2) Figure 2. By 2030, maximum temperatures rise by 0.5 to 1.5°C over most of Victoria, with slightly more warming in spring and less warming in winter and in southern areas. By 2070, maximum temperatures rise by 1.0 to 5.0°C over most of Victoria with spatial variation similar to those for 2030. The range of maximum temperature rise for 2100 was not available.

4.4.2 Extreme Daily Temperatures

Small changes in average seasonal temperature can be associated with large changes in extreme daily temperatures. In Australia, the frequency of extreme hot events (e.g. hot days and nights) has generally increased since the mid-1950s, and the frequency of extreme cold events (e.g. cold days and nights) has generally decreased. From 1957 to 2004, the Australian average shows an increasing trend in hot days (35oC or more) of 1 day per decade, an increasing trend in hot nights (20oC or more) of 1.8 nights per decade, a decreasing trend in cold days (15oC or less) of 1.4 days per decade and a decreasing trend in cold nights (5oC or less) of 1.5 nights per decade (Nicholls and Collins, 2005). Further changes in extreme daily temperatures are likely to occur due to the effects of global warming. Cape Otway has been used to project changes in extreme daily maximum temperatures due to the high quality observed daily data from the Bureau of Meteorology from 1964-2003 and its coastal similarities and relative position to Barwon Heads. The projected average warming values for 2030 and 2070 in Appendix B Figure 2 were applied to the observed data for Cape Otway. The results for Mark 2 indicate that the average number of days above 35°C increases 10 to 60% by the year 2030, and 20 to 100% by 2070. The increases for extreme daily temperature in 2100 were not available.

4.4.3 Relative Humidity

Projected changes in annual and seasonal average humidity are shown in Appendix B Figure 4. By 2030, the annual average humidity for the region around Barwon Heads increases 0 to 3%, with greatest increases in winter and autumn. By 2070, humidity increases 0 to 7%. No relative humidity data for 2100 was available.


4.4.4 Impacts on Materials from Temperature and Humidity

Increases in temperature will accelerate the degradation of a range of asphalt, protective cladding, coatings and sealants typically used on bridges. Increased temperature levels also cause expansion of concrete joints and steel in bridges which over time can generate fatigue and degradation of structural elements of the bridge. Increased humidity will lead to an increase in the rate of corrosion of metals. This can lead to increased maintenance costs and an earlier renewal of the bridge asset. Safety could also be an issue with any accelerated physical degradation as the bridge could potentially be more vulnerable to damage from extreme storm events. The types or blends of materials used can be specified in a design response that operates within the range of the climate conditions of the future rather than being designed for the climate conditions of the past. Climate change impacts need to be incorporated into the design specifications of the bridge design to ensure the life expectancy of the asset is not significantly reduced. In this case the proposed bridge has a life expectancy of 100 years.

FINDING 4: Climate change impacts on materials need to be considered in the design phase of the bridge to reduce the risk of climate change accelerating degradation of the bridge asset over time.

To mitigate the climate change risk to the bridge asset it is recommended that:

RECOMMENDATION 1.

Vic Roads specify the inclusion of climate change considerations as part of the design standards used and materials specified in the design phase of the bridge be selected to avoid any accelerated degradation of the bridge asset over time.


5.0 Conclusion The sea-level rise and increased intensity of extreme wind events generated by climate change for 2030, 2070 and leading up to 2100 are unlikely to significantly erode the Ocean Grove Spit and generate instability impacting on the bridge. Similarly the western bank of the Barwon River is expected to remain stable under the impacts of climate change. The Barwon Head Bridge is unlikely to be impacted by increased intensity of extreme rainfall events or sea-level rise generating higher river and tidal flooding from climate change. It is important that increased temperature and humidity impacts generated by climate change on materials are considered in the design phase of the bridge to avoid accelerated degradation the Barwon Heads Bridge which could potentially reduce the expected life of the asset.


6.0 Selected Resources Climate change – general

CSIRO, 2001: Climate Change Projections for Australia, 8pp. Available from: <http://www.dar.csiro.au/publications/projections2001.pdf>

IPCC, 2001: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change [Houghton, J.T., Y. Ding, D.J.Griggs, N. Noguer, P.J. van der Linden, X. Dai, K. Maskell, and C.A. Johnson (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

IPCC, 2001: Climate Change 2001: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change [McCarthy, J.J., O.F. Canziani, N.A. Leary, D.J. Dokken, and K.S. White (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Pittock, A.B., ed. (2003) Climate change: an Australian guide to the science and potential impacts. Canberra, ACT: Australian Greenhouse Office. 239 p. <http://www.greenhouse.gov.au/science/guide/>

Climate change impacts

Allen Consulting Group (2005). Climate change risk and vulnerability: promoting an efficient adaptation response in Australia. Report to the Australian Greenhouse Office by the Allen Consulting Group, 159 pp.

CSIRO (2001) Climate change impacts for Australia, 8pp. Available from: < www.marine.csiro.au/iawg/impacts2001.pdf >

Climate change in Victoria

Jones, R.N. and K.L. McInnes (2004) A scoping study on impact and adaptation strategies for climate change in Victoria. Victorian Department of Sustainability and Environment. <http://www.greenhouse.vic.gov.au/files/Vic_I_A_Report_final.pdf>

Port of Melbourne Authority (1992) Victorian Coastal Vulnerability Study. Port of Melbourne, Melbourne.

Suppiah, R., Whetton, P. H. and I.G. Watterson, (2004). Climate change in Victoria: assessment of climate change for Victoria: 2001-2002 / undertaken for Victorian Department of Sustainability and Environment. Aspendale, Vic.: CSIRO Atmospheric Research. 33 p. <http://www.dar.csiro.au/publications/suppiah_2004a.pdf>

Whetton, P.H., R. Suppiah, K.L McInnes, K.J Hennessy and R.N. Jones (2002) Climate change in Victoria. High resolution regional assessment of climate change impacts. Vic Department of Natural Resources and Environment. <http://www.greenhouse.vic.gov.au/climatechange.pdf>

Climate change and infrastructure

Abbs, D. (2002) Climate change and Australia’s coastal communities, CSIRO < www.cmar.csiro.au/e-print/open/CoastalBroch2002.pdf >

Auld H. and D. MacIver (2005) Cities and communities: the changing climate and increasing vulnerability of infrastructure, Occasional paper- Adaptation and Impacts Research Group, Environment Canada,. Toronto.

Austroads (2004) Impact of climate change on road infrastructure. Report AP-R243/04. <Available at http://www.onlinepublications.austroads.com.au/script/Details.asp?DocN=AR0000048_0904>

Three Regions Climate Change Group (2005) Adapting to climate change: A checklist for development. London Climate Change Partnership, the South East Climate Change Partnership and the East of England’s Sustainable Development Roundtable. < http://www.gos.gov.uk/gol/docs/199952/adapting_climate_change.pdf>

US Department of Transportation (2002) The potential impacts of climate change on transportation: workshop summary and proceedings. US Department of Transportation Center for Climate Change and Environmental Forecasting. <Available at http://climate.volpe.dot.gov/workshop1002/>


http://www.greenhouse.gov.au/science/guide/

http://www.marine.csiro.au/iawg/impacts2001.pdf

http://www.dar.csiro.au/publications/suppiah_2004a.pdf



http://www.greenhouse.vic.gov.au/climatechange.pdf

http://www.onlinepublications.austroads.com.au/script/Details.asp?DocN=AR0000048_0904

http://www.gos.gov.uk/gol/docs/199952/adapting_climate_change.pdf

7.0 References Alexander, L.V., Zhang, X., Peterson, T.C., Caesar, J., Gleason, B., Klein Tank, A.M.G., Haylock, M.,

Collins, D., Trewin, B., Rahimzadeh, F., Tagipour, A., Rupa Kumar, K., Revadekar, J., Griffiths, G., Vincent, L., Stephenson, D.B., Burn, J.,, Aguilar, E., Brunet, M., Taylor, M., New, M., Zhai, P., Rusticucci, M., Vazquez-Aguirre J. L. (in press). Global observed changes in daily climate extremes of temperature and precipitation. International Journal of Climatology.

Church, J.A., White, N.J., Coleman, R., Lambeck, K. and Mitrovica, J.X. (2004). Estimates of regional distribution of sea level rise over the 1950-2000 period. Journal of Climate, 17, 2609-2625.

Corangamite Catchment Management Authority (2005) Barwon River Estuary Flood Study – Tidal Surge Analysis for 1% AEP Flood Levels.

Hennessy, K., McInnes, K., Abbs, D., Jones, R., Bathols, J., Suppiah, R., Ricketts, J., Rafter, T., Collins D. and Jones, D. (2004). Climate Change in New South Wales, Part 2: Projected changes in climate extremes. Consultancy report for the New South Wales Greenhouse Office by the Climate Impact Group of CSIRO Atmospheric Research and the National Climate Centre of the Australian Government Bureau of Meteorology, 79 pp.

Hughes, L. (2003). Climate change and Australia: trends, projections and impacts. Austral Ecology, 28, 423-443.

IPCC (2001). Climate Change 2001: The Scientific Basis, Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Houghton, J.T., Ding, Y., Griggs, D.J., Noguer, M., Van Der Linden, P.J. and Xioaosu, D (eds), Cambridge University Press, Cambridge, 944 pp.

Jones, P.D., and A. Moberg. 2003. Hemispheric and large-scale surface air temperature variations: An extensive revision and an update to 2001. J. Climate 16, 206-223.

Karoly, D. and Braganza, K. (2004). Attribution of recent temperature changes in the Australian region. J. Climate, 18(3), 457-464.

McInnes, K.L., Abbs, D.J. and Bathols, J.A.. (2005). Climate change in eastern Victoria: Stage 1 report – the effect of climate change on coastal wind and weather patterns. CSIRO Marine and Atmospheric Research, Aspendale, Vic, 26 p.

Mitchell, T.D. (2003). Pattern scaling. Climatic Change, 60, 217-242. Nicholls, N. and Collins, D. (2005). Observed climate change in Australia over the past century.

Energy and Environment, in press. SRES (2000). Special Report on Emission Scenarios: Summary for Policymakers. A Special Report of

Working Group III of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK, http://www.ipcc.ch/pub/sres-e.pdf, 27 pp.

Whetton, P.H. (2001). Methods used to prepare the ranges of projected future change in Australian region temperature and precipitation. http://www.dar.csiro.au/impacts/docs/how.pdf

Whetton, P.H., McInnes, K.L., Jones, R.N., Hennessy, K.J., Suppiah, R., Page, C.M., Bathols, J., Durack P. (2005). Climate change projections for Australia for impact assessment and policy application: A review. CSIRO Technical Paper. http://www.cmar.csiro.au/e-print/open/whettonph_2005a.pdf

Whetton, P.H., Suppiah, R., McInnes, K.L., Hennessy, K.J. and Jones, R.N. (2002). Climate change in Victoria: high resolution regional assessment of climate change impacts. CSIRO consultancy report for Dept. Natural Resources and Environment Report, Victoria. 44 pp.


http://www.cmar.csiro.au/e-print/open/whettonph_2005a.pdf

http://www.cmar.csiro.au/e-print/open/whettonph_2005a.pdf

Appendix A Curriculum Vitae

Barwon Bridge - Climate Change Impacts Independent Advisory Committee Hearing T:\600 177 06 Barwon Heads Bridge\Task 1.06 - Climate Change Impacts\Barwon Heads_Expert Witness StatementClimateV2.doc Revision V1 September 2006 Page a

Michael Nolan Senior Consultant - Sustainability

QualificationsBachelor of Science (Environmental

Resource Management), SouthernCross University

Certificates: Environmental ChangeManagement. Business Management.

OHS.

Professional affiliationsMember, EIANZ

Member, Green Office Action NetworkAustralia

Member, Association of Waste AndRecycling Education

Member, Australian Campuses TowardsSustainability

Member, Waste Wise MelbourneNetwork

Career highlights

Michael is an environmental professional with twelve years experience managing sustainability and environmental change outcomes for business, government, community and educational institutions. He has extensive experience in strategic planning, applied sustainability, energy, greenhouse and climate change, waste minimisation, built environment and behaviour change management. Prior to joining Maunsell, Michael worked as Director and Principal Consultant for Sustainable Change consulting to a broad range of clients regarding the development and implementation of sustainability policy, plans, audits, training and marketing for medium and large multi-site organisations nationally. Michael also worked as the strategic planner – sustainability for RMIT University and as an environmental consultant with Terra Nova – Environmental Strategies. Sustainable Development Michael has extensive experience in delivering environmentally sustainable development (ESD) plans for facilities, corporations and local government. Focusing on strategies to integrate sustainability outcomes into core policy, strategies and operations. He has facilitated environmental building design for major projects and the environmental management and ESD plans for significant Australian Defence Department contracts. Climate Change, Greenhouse and Energy Management Michael has project managed several climate change impact and risk projects relating to infrastructure. Michael has conducted numerous greenhouse, energy audits and established Greenhouse Challenge agreements. Michael’s understanding of energy efficiency, behaviour change management, waste emissions, transport and green procurement provides a comprehensive greenhouse and carbon disclosure service, including monitoring, verification and reporting processes. Waste Minimisation Michael has conducted numerous waste audits, developed waste minimisation plans and purchasing strategies across a number of sectors including local and state government, medical, education, construction and corporate. Michael is experienced in delivering Waste Wise Certification with Sustainability Victoria.

March 2005 Page 1 of 5


Detailed experience

Maunsell Australia July 2004 to present – Senior Sustainability Consultant Sustainable Development • Infrastructure and Climate Change Risk Assessment of Victoria, Dept

of Sustainability and Environment in conjunction with CSIRO. • Green Buildings Approvals Audit, Adelaide City Council. • Barwon Bridge Expert Report on Climate Change Impacts. • Webb Dock Greenhouse Assessment, Port of Melbourne. • Victorian Government Strategic EMS Audit Framework for the

Commissioner for Environmental Sustainability (Victoria) (2004 and 2006 audits).

• EMS Auditing of 12 Victorian Government Departments/Agencies. • Facilitated ESD concept design for several building and infrastructure

developments including a world class green building in Tianjin, China. • Developed Environmental Management Plans for major rail and road

infrastructure projects. • GreenEdge project – Development of a mixed mode commercial

development sustainability ratings tool in collaboration with Bassett for Banyule City Council and Sustainability Victoria.

• Sustainability advising for several major infrastructure projects. • Developed planning strategies for Transfield Services to deliver ESD

and environment management outcomes for significant defence department contracts.

• Sustainable Campus Group Project – includes facilitation of group, sector bulletin, sustainable campus reporting and implementing cultural change training and conducting pilot sustainable campus report for the universities and TAFE in Victoria.

• Environmental best practice case studies of Victorian campus operations for EcoRecycle Victoria.

• Sustainable Energy Innovation for Educational Facilities for the Sustainable Energy Authority Victoria.

• City of Boorondara EMS training development. • Greenhouse Challenge Review of Yarra Valley Water. • Green Office Programs, clients include South East Water, Xavier

College, Australian Defence Department, Country Fire Authority and RMIT University.

• Sustainable Paper Usage Project for Malleson Stephen Jacques in partnership with Green Collect.

• Coordinate the Green Office Program for Maunsell Australia’s Victorian Office.

Sustainable Change February 2000-June 2004 – Director & Principal Consultant Sustainable Development • Developed planning strategies for Spotless Services Limited to

deliver ESD and environment management outcomes for major projects, including significant defence department contracts.

C:\TEMP\Temporary Internet Files\OLK2E\Nolan Michael Aug06.doc Page 2 of 5


• Environmental risk assessments for the Victorian Department of Treasury and Finance in conjunction with Global Sustainability @ RMIT and Alan Consulting.

• Facilitated and produced a Local Agenda 21 (ESD) paper for Ballina Shire Council.

• Benchmarked the environmental operations of Australia’s top 13 universities.

• Reviewed strategic planning documents for the Queensland Government EPA - Sustainable Industries.

• Developed and facilitated environmental policy, strategies and management systems for the following educational institutions: Central Queensland University, Griffith University, Southern Cross University, University of South Australia, Kangan Batman TAFE, Box Hill TAFE and RMIT University.

• Reviewed the Cellulose Valley Technology Park Sustainable Management Plan.

• Developed environmental assessment / risk management software and facilitation packages in conjunction with Periscope Consulting.

• Subcontracted to Sustainable Built Environment (SBE) to set building design targets for energy, waste and water use for several building projects.

• Provide expert advice to the Australian Vice-Chancellors Committee and the Australian Campus Union Managers Association on improving university sustainability and education outcomes nationally.

• Developed a streamlined Green Office Program for reducing energy, waste and purchasing costs for the finance and legal industries.

• Organised a ‘Sustainability Debate’ for the Royal Australian Institute of Architects for world Architect Day with Sustainable Market Developments.

• Lectured in ‘Environmental Economics’ at RMIT University and in ‘Environmental Policy Implementation and Monitoring’ and ‘Managing Environmental Performance’ at Box Hill TAFE.

• Executive steering committee member for the Sustainable Education Roundtable for the Victorian Department of Sustainability and Environment.

Corporate Social Responsibility • Business development and strategy development for Green Collect to

deliver corporate-community collaboration for social and environmental outcomes in the CBD. The program boasts engagement with 20 corporate members and over 200 hospitality businesses in Melbourne to deliver green office programs, waste and energy auditing, paper and purchasing assessments, cork recycling collections and staff culture programs.

• Business development and strategy development for CERES Environmental Park for delivery of waste, energy and greenhouse services to the local community, schools and business. Review of strategic frameworks and staff culture to deliver core business outcomes.



Greenhouse and Energy Management • Greenhouse Audit of CERES Environmental Park • Energy Audit of the Box Hill TAFE campuses • Energy Audit of Southern Cross University • Energy Audit of Central House, Collins St Benevolent Society • Review of the Greenhouse Challenge performance for the University

of South Australia Waste Minimisation • Conducted waste management audits for Lismore City Council’s

domestic and commercial waste streams • Developed and coordinated the Waste Wise Campus Forums for all

the Universities and TAFE in Victoria • Facilitated the National Packaging Covenant Forum for Environment

Victoria • Waste audit of the Victoria Police Centre waste streams, practices

and collection systems RMIT University May 1998-Feb 2000 – Strategic Planner - Sustainability Sustainability Development • Strategic, action and business planning for the university in

consultation with the university community, business partners and various government bodies.

• Initiated and project managed the ‘Greening RMIT project’, the ‘RMIT University Environmental Building Design Guidelines’, the ‘Rooftop Garden’ development and the RMIT ‘Green Purchasing Policy’.

• Facilitated staff culture programs including staff environmental advocates network and student green team.

• Developed the ‘Greenhouse Challenge’ agreement with the Australian Greenhouse Office

• Conducted periodic energy audits of RMIT University facilities across Victoria

• Developed a ‘Sustainable Transport’ Strategy for the main city campus

• Facilitated the ‘RMIT Waste Minimisation Strategy’ and ‘Staff Waste Outreach Project’

• Project managed the first ‘Waste Wise’ certification in Victoria • Conducted periodic waste audits of RMIT University facilities across

Victoria Terra Nova – Environmental Strategies February 1997-March 1998 – Environmental Consultant Environmental Auditing • Conducted environmental audits for several Coles Supermarkets

(waste, trade waste and water). • Project managed the development and delivery of an environmental

audit (energy, waste, water, chemicals and purchasing) program for North Yarra Community Health.



• Assessed waste and recycling station performance for Visy Recycling.

• Developed financial and environmental savings reports for broad range of clients.

National Union of Students – Victoria December 1995-January 1997 – Environment Officer Sustainable Development • Coordinated state wide and national campaigns for university

environment organisations. • Developed and facilitated the Cross-Campus Environment Network. • Project managed the business development five new environment

centres in Victorian universities. • Lobbied and worked with government, Environment NGOs, media

and universities. La Trobe University – Union June 1995 - November 1996 – Vice-President Sustainable Development • Chairperson of Development Committee for several major building

development projects. • Developed the La Trobe University Union Environment Policy. La Trobe University – Student Representative Council December 1994 - December 1995 – Environment Officer Sustainable Development • Coordinated several environmental, social and sustainability projects

and events including revegetation projects, Car Pool program and green purchasing campaigns.

• Established cultural programs with several indigenous communities throughout Victoria.

Employment record

from – to employer/description of duties

Jul 2004 to Present

Maunsell Australia Senior Sustainability Consultant

Feb 2000 to Jun 2004

Sustainable Change Director & Principal Consultant

May 1998 – Feb 2000

RMIT University Strategic Planner - Sustainability

Feb 1997 – Mar 1998

Terra Nova – Environmental Strategies Environmental Consultant

Dec 1995 – Jan 1997

National Union of Students – Victoria Environment Officer

Jun 1995 – Nov 1996

La Trobe University – Union Vice-President

Dec 1994 – Dec 1995

La Trobe University – Student Representative Council, Environment Officer


Appendix B CCAM Mark 2 Climate Model Projections

Barwon Bridge - Climate Change Impacts Independent Advisory Committee Hearing T:\600 177 06 Barwon Heads Bridge\Task 1.06 - Climate Change Impacts\Barwon Heads_Expert Witness StatementClimateV2.doc Revision V1 September 2006 Page b

Annual

Summer

Winter

Autumn

Spring

Tmax 2030 High

Annual

Summer

Winter

Autumn

Spring

Tmax 2070 Low

Figure 2: Average seasonal and annual changes (°C) in maximum temperature for 2030 and 2070 relative to 1990, for the CCAM Mark 2 model.

Barwon Bridge - Climate Change Impacts Independent Advisory Committee Hearing T:\600 177 06 Barwon Heads Bridge\Task 1.06 - Climate Change Impacts\Barwon Heads_Expert Witness StatementClimateV2.doc Revision V1 September 2006 Page b-1

Annual

Summer

Winter

Autumn

Spring

Tmax 2070 High

Annual

Summer

Winter

Autumn

Spring

Tmax 2030 Low

Figure 3: Average seasonal changes (%) in extreme daily wind-speed (99th percentile) for 2030 and 2070 relative to 1990, for the CCAM Mark 2 model.


Summer

Winter

Autumn

Spring

CCAM (Mark2)

Summer

Winter

Autumn

Spring

CCAM (Mark2)

Summer

Winter

Autumn

Spring

CCAM (Mark2)

Summer

Winter

Autumn

Spring

CCAM (Mark2)

Figure 4: Average annual and seasonal changes (%) in relative humidity for 2030 and 2070 relative to 1990, for the CCAM Mark 2 model.


Annual

Summer

Winter

Autumn

Spring

Humidity 2070 Low Annual

Summer

Winter

Autumn

Spring

Humidity 2070 High

Annual

Summer

Winter

Autumn

Spring

Humidity 2030 Low Annual

Summer

Winter

Autumn

Spring

Humidity 2030 High

Documents

Barwon Heads Bridgebarwonheadsassociation.com/files/Maunsell - Barwon... · 4. Climate change impacts on materials need to be considered in the design phase of the bridge to reduce