INFRASTRUCTURE AUSTRALIA

BUSINESS CASE

IMPACTS OF CLIMATE CHANGE ON

SWAN AND CANNING RIVER FORESHORES

OCTOBER 14, 2008

“Climate change is one of the biggest threats facing local government and, for coastal councils, the implications are of tidal wave proportions. More frequent and intense storms, cyclones and sea level rises will be coupled with shoreline erosion, saltwater inundation, flooding and high-velocity winds. Predicting the scale of damage to coastal property, infrastructure and amenity is a difficult business, with projections varying between scientists and climate change experts to governments and insurers. But what is certain is that tomorrow’s problems are in the hands of today’s politicians and planners......”

(GovernmentNews September 2008)

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1.0 EXECUTIVE SUMMARY

This submission has been prepared by the City of South Perth, one of 21 Local

Government Authorities that has river foreshores in the Swan/Canning System.

Additional information has been provided by the Swan River Trust, City of Perth, City

of Nedlands, City of Belmont, City of Melville, Town of Mosman Park, Tourism WA, WA

Department of Planning and Infrastructure and the Western Australian Local

Government Association.

The Swan Canning River System is the dominant geographic feature of the Perth

metropolitan area w ith 1.5 million from a total of 2.1 million Western Australians, or

71% of the State’s population living in the system’s w ider catchment area. By 2030 it is

anticipated that 2 million people w ill live in the catchment area, an increase of 33%

that will put further pressure on the system. The rivers are a major focal point for

much of the State’s economic development and integral to Western Australia’s

identity, heritage and community well being.

The economic, social and environmental sustainability of the Western Australian

community is at risk due to negative climate change impacts. Specific areas of need

are ongoing damage to infrastructure designed to protect the river foreshore from

climate and weather conditions and, a lack of a coordinated and appropriately

funded response to address foreshore infrastructure deterioration.

Infrastructure related to this submission includes riverwalls, groynes, foreshore

footpaths and promenades, stormwater drainage, jetties and wave attenuation

structures. The stability of non built sections of the system foreshore is also a significant

issue, however this area is not covered in this submission due to the nature of the

Infrastructure Australia initiative.

The current state/local government response to deteriorating foreshore infrastructure

is characterised by grossly inadequate funding levels whereby local governments are

competing against each other for limited funds to protect all foreshore infrastructure.

The Swan River Trust which administers restorative riverwall and foreshore protection

funding on behalf of the State Government, has an annual allocation of only $1

Million to distribute to all 21 river front LGAs. The value of works urgently required, as

identified by the Swan River Trust however, is in the order of $85 Million.

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This, against an historic backdrop where different agencies, government

departments and local governments have had varying levels of responsibility for the

maintenance of different sections of the foreshore, has resulted in ‘non action’ and

even court action between levels of government to determine liability. If this

response continues the increasing episodes of severe weather incidents and climate

change related issues w ill impact further on;

• Major transport road and rail links to the Perth CBD, in particular the Kw inana

freeway and the Perth - Mandurah Rail link.

• Amenity and economic development of significant foreshore developments

in adjacent Local Government Authorities such as those in the Perth CBD,

South Perth and Melville.

• The value of the Swan River as an ‘Icon’ to Western Australians and to visitors

to Perth

It is not intended that this submission be comprehensive in addressing all aspects of

this issue, rather a first step in responding to identified immediate needs as well as a

catalyst to develop a sustainable strategy for the future.

This submission recommends a two part response to address current and future

infrastructure requirements relating to the river foreshores of the Swan Canning

system;

1. Addressing identified works including repairing or replacing currently

damaged built shoreline infrastructure at an estimated cost of

$85.65Million (SRT, 2008 &COSP 2008).

2. The Commonwealth, in partnership with Local and State Government,

develop and resource a Regional Response Strategy by conducting a

comprehensive infrastructure assessment. This would incorporate

stormwater drainage, groynes, jetties, wave attenuation walls and then

identify the most appropriate adaptive and mitigation strategies and a

financial plan to account for other vulnerable infrastructure on the Swan

and Canning Rivers.

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2.0 PROBLEM IDENTIFICATION AND JUSTIFICATION STATEMENT

o What gives this issue National Significance

Fig. 1: View over Perth Water t o Sout h Perth foreshore wit h Melville Water beyond the Narrow s Bridge.

Photograph t aken from Council House, Perth CBD, 2008.

The Swan River is Western Australia’s most recognisable feature. It is the first impression

most visitors have of the State and it is w idely used to promote the State and the

country to international tourists – such as to a global television audience of 400 million

for the Red Bull Air Races. Data from Tourism WA indicate that the direct spend from

2006 Red Bull Air Races in Perth was $12.9 Million (excluding airfares).

The river is also a central focus for many business and accommodation developments

such as Burswood International Resort, Perth Convention Centre and Old Swan

Brewery Apartment complex all located in close prox imity to the Perth CDB. At the

river mouth the Fremantle Port complex is an integral part of the state’s second

largest City.

Tourism WA advise that in the period 2005 - 2007, 3,020,800 visitors stayed in Perth

(intra state, interstate and international) each for an average of 7.6 nights spending a

total of $61,201,408 (excluding airfares). Many of these tourists took a ferry ride across

the river as part of the 600,000 annual visitors to the Perth Zoo which is located in the

City of South Perth.

A community survey was conducted by the Swan River Trust in 2007 to assess the

“Fut ure Values and Aspirat ions for the Swan and Canning Rivers”. A key finding is that

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these rivers are, “...considered iconic - an important community asset that are

strongly valued as a key feature of Perth’s recreation, social and cultural landscape”

Core Problem:

The Swan River Trust released the report entitled Potent ial impacts of Climate Change

on t he Swan and Canning Rivers in late 2007. This report is a first attempt to

investigate the many potential impacts on these river systems from climate change.

Two scenarios for climate change were investigated, based on the

Intergovernmental Panel of Climate Change A2 and B1 global scenarios (IPCC

2007).

The key climate change impacts on infrastructure such as riverwalls are rising water

levels and changes in the frequency and intensity of storms (SRT, 2007). Future

changes in sea level, particularly on a regional basis, are uncertain. SRT (2007)

presents two scenarios for sea level rise for south west Western Australia, w ith

increases in sea level rise between 0.06 - 0.17 m to 2030 and 0.19 - 0.74 m to 2100.

Research from Church et al (2007) suggests that since the mid 1990’s sea level rise

may be tracking towards the upper end of these projections. In order to mitigate the

effects of climate change on infrastructure, SRT (2007) suggests considering increased

protection of foreshore assets and sufficiently increasing the elevation of

infrastructure.

The follow ing diagram depicts mean sea level rise in the last 100 years of 0.17m. The

average rate was ~ 1.8 mm per year between 1963 and 2003, but was ~ 3.1 mm per

year between 1993 and 2003. (Measured at the river mouth, Fremantle)

Fig. 2:

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This graph illustrates an increasing number of higher , high tide events over an 18 year

period, measured at Barrack Street (Perth foreshore).

Number of days when water levels were greater or equal to given values - >=150 cm

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2

3

4

5

6

7

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1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

(Number)

Barrack Street Water Levels Linear (Barrack Street Water Levels)

Fig. 3:

The follow ing images demonstrate the kind of overtopping events that are now

occurring w ith increased intensity and regularity. These types of events are

predicted to worsen as climate change impacts are felt.

Fig. 4: W aves overt opping a seawall along t he Kwinana Freeway during a w int er st orm.

Source: The West Australian new spaper (13 July 1995)

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Fig. 5: Riverside Drive is a main road link t o t he Pert h CBD and a st ate t ourism showcase and a prime

viewing spot for t he Red Bull Air Races and Skyshow – Flooding in 2003.

Fig. 6: Tide surge in 2003 – Dual use path and Old Swan Brewery Apartment Complex

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Fig. 7: Sir James M it chell Park ( Sout h Pert h foreshore) , a sect ion of t he City’s 18.5 kilomet re river

shoreline City of Sout h Perth foreshore - St orm and tidal surge July 2007.

Consequences:

Key impacts on infrastructure include increased erosion and damage of protective

walls as well as increased frequency of inundation of low lying features such as paths,

roads and footpaths (SRT, 2007).

Case Study – Sir James Mitchell Park, South Perth foreshore

In recent years, storm events and tidal surges have regularly inundated the foreshore

of Sir James Mitchell Park in South Perth. The events have resulted in significant

erosion to areas of the foreshore and severe damage to sections of the river wall. As

a result, the river wall in the park requires varying degrees of maintenance and in

some cases raising to cope with these new environmental pressures. This is

particularly apparent for a 475 metre section of wall either side of the Mends Street

Jetty, which is now regularly over topped during high tide and storm events.

This section of wall requires urgent maintenance to prevent blowouts and lifting to the

level of the adjacent pedestrian path as there has been frequent evidence of over

topping from storm and tidal events. Furthermore these repairs are urgently required

to reduce risk to the public. The foreshore in the vicinity of the car park, at the end of

South Perth Esplanade, has no coastal protection. As a result, it is severely eroded

and requires immediate attention to protect trees and car park infrastructure, and

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ultimately the local residential and recreational environment. The estimated cost of

repairing this 475 metre section of wall is $2.6 Million. A grant application has been

made to the Swan River Trust to assist in meeting this cost however the Trust only has

a $1 M illion fund each year to support such repairs and improvements across the

whole of Perth.

3.0 PROBLEM ASSESSMENT

Outlined below are some examples of projects already undertaken or proposed by

Local Government Authorities to illustrate the scale of the issue. What is clear from

these examples is that a sustainable and effective response is not possible w ithout an

holistic and appropriately funded regional approach.

City of South Perth

• City of South Perth is a Peninsula surrounded on three sides by the Swan and

Canning Rivers; it has 18.5 kilometres of shoreline.

• The Kwinana Freeway and Mandurah-Perth Rain Link runs for 5.3 kilometres

immediately adjacent to the City’s western shoreline. The Swan River Trust has

identified the riverwalls along this shoreline as a requiring urgent

restoration/replacement at an estimated cost of $27.83 Million.

• The vista towards the Perth CBD across Perth Water from the South Perth

foreshore is an iconic image of Western Australia. This foreshore hosts massive

crowds of up to 250,000 for events such as the Red Bull Air Races and Australia

Day Skyshow. In addition an international television audience of 400 million

watched the 2007 Red Bull Air Races.

Fig. 8. Part of t he 250,000 RedBull Air Races audience on t he Sout h Perth foreshore

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• The follow ing two images illustrate the issue and one proposed solution to the

dire condition of the river walls at Sir James Mitchell Park, which as previously

stated, is a widespread problem along the Swan and Canning Rivers.

Fig. 9: Sout h Pert h foreshore M ends St t o Queen St reet jett y. Tidal surge 2003

Fig 10: Proposed Riverwall/Boulevard at t he same sect ion of t he foreshore at an

est imated cost of $2.6 Million (475 met res at $5,500 per met re).

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City of Perth

The City of Perth has 11.87 kilometres of river foreshore much of which is developed

with riverwall protective structures adjacent to, or integrally linked w ith major

transport routes, jetties, boardwalks, promenades, restaurants, medium density

housing etc. In many instances the only method of working on the ageing riverbank

infrastructure is from the river-side resulting in very high construction costs (up to

$10,000 per metre). Recent works include;

• 240 metre section of gabion wall replaced in 2004-05 at a cost of $1.2 Million.

• 420 metre section of gabion wall replaced in 2006 at a cost of $2.2 Million.

Identified works requiring action in a five year time frame on a section of foreshore

between Barrack St Jetty and Car Park 1, Mounts Bay Road include;

Est. Project Cost

Replacement of 500 metres of ‘gabion’ style riverwall West of

the Old Swan Brewery apartment complex . Construction access

by river only. Estimated cost up to $10,000 per metre.

$4 - $5 Million

Replacement of 320 metres of ‘gabion’ style riverwall between

car parks 1 and 2.

$1.3 Million

Reconstruction of 340 metres of ‘reno mattress’ style riverwall in

‘section 3’.

$1 Million

Maintenance to 850 metres of riverwall at sections 1, 5 & 6. $850,000

ESTIMATED FIVE YEAR TOTAL $7.1 - $8.15Million

Fig. 11: Riverwall work at M ounts Bay Road, undertaken from t he river s ide due t o lack of access

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City of Nedlands

The redamming and walling of the Nedlands foreshore began during the 1930s as an

anti depression measure to assist unemployed workers who were paid sustenance

wages. The 1,600 metres of riverwall on the Nedlands foreshore is subject to annual

severe weather incidents and w ill require complete replacement w ithin the next few

years at an estimated cost of $5,000 per metre or $8 Million.

City of Belmont

Over the period 2007-2011 Belmont has identified Capital works of $2.8 Million related

to urgent riverbank restoration. Funding these works is simply not achievable as this

figure represents 31% of the City’s entire Capital Works budget over the same period.

The only source of external funding available to assist with these works is from the

Swan River Trust’s annual allocation of $1M illion riverwall fund which is accessed by all

21 LGAs adjacent to the river system.

4.0 SOLUTIONS

Part 1. Repair / Alter Infrastructure

Allocate an estimated $85.65 Million to resource urgent repairs to infrastructure as

identified by the Swan River Trust, the City of South Perth and other Local Government

Authorities as indicated in this submission. Additionally protect current infrastructure in

the design, maintenance and replacement of jetties, boat pens, ramps, river walls

etc.

Part 2. Develop a Regional Response Strategy

Develop a long-term response strategy for the Swan and Canning Rivers

incorporating a detailed financial plan. This would require reviewing past and ex isting

adaptive and mitigation strategies, locally and in other regions, in order to identify

those most appropriate to the Swan and Canning Rivers. Furthermore it would assess

major impacts on climate change such as developing set-back guidelines, foreshore

revegetation and erosion control strategies.

Such a strategy would include a triple-bottom-line assessment for each location to

determine the particular priorities and potentia solutions. For example, purely

environmental impacts or there may also be economic and social costs/benefits to

consider. Hence it would be necessary to take an inter-agency approach, working

collaboratively w ith the Commonwealth, Local Government Authorities, Swan River

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Trust, State Treasury, Main Roads WA, Tourism WA and other relevant agencies and

organisations to gain a broad and accurate perspective.

To illustrate, the most holistic solution for certain ‘iconic’ locations would be to

construct promenades around the Swan and Canning Rivers, such as that proposed

on the South Perth foreshore at Sir James M itchell Park. This would be a key strategy

for attracting and retaining visitors (recreational and tourists). As confirmed by the

Swan River Trust community survey, there is a strong preference for passive

recreational facilities and infrastructure on river foreshores such as walking paths (SRT,

2007). i.e. economic and social benefits apply.

While the Swan River Trust and individual local government authorities have made

substantial progress to understand aspects of the problem, an holistic and integrated

strategy is required. More importantly however, financial solutions are required to

support the implementation of this strategy to prevent further damage and

economic loss.

5.0 ESTIMATED COSTS

Part 1 - Repair Currently Damaged Built Shorelines

The Swan River Trust has identified in its March 2008 Swan and Canning Rivers

Foreshore Assessment and Management Strategy, maintenance and replacement

works required are significant as demonstrated in the following table;

Est

cost/km

($M)

Total

km

Approx total cost

($M)

Maintenance of structure 1.5 12 18

Replacement of structure 5.25 12.2 64.05

City of South Perth

Riverwall/Pedestrian Boulevard

5.2 0.5 2.6

TOTAL $85.65M

Part 2 - Develop and Resource a Regional Response Strategy

Collaborative work is required between stakeholders as described previously to

scope and cost a Regional Response Strategy.

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6.0 RISK ANALYSIS Should vulnerable river walls and other infrastructure not be repaired in a timely

manner, it will result in further severe damage to ex isting infrastructure and extensive

economic losses on many levels. Specifically, sudden storm surges and rising water

levels w ill affect:

- Roads, vehicles and traffic conditions with road surface damage and car

breakdowns expected to rise as well as freeway and rail closures;

- Damage and related costs to foreshore and residential assets from inundation, w ith

implications for the insurance industry, as risk of exposure to extreme events increases;

- Loss of recreational areas such as riverside parks due to inundation (SRT, 2007); and

- Injury to the public as a result of damaged infrastructure, accidents etc.

- Reduced tourism experience and reputation w ith a resultant reduction in tourism

numbers and revenue

In May 2005 a water main adjacent to the Kw inana freeway burst, closing the

freeway and causing severe disruption to business in the Perth CBD. Similar disruptions

occur on the freeway north as lanes are regularly closed during severe storm events.

(see: Fig.4) Subsequent to the May 2005 incident the Perth/Mandurah Rail link which

runs along the freeway has opened making this route more important to the State’s

economy. In addition to the direct cost of repairing damage caused by inundation,

the flow on cost to business operations could inevitably be very significant.

7.0 PROJECT OUTCOMES AND COST-BENEFIT A response to the issue of foreshore vulnerability as outlined in the submission, utilising

research already undertaken to identify immediate solutions will result in the

stabilisation of the Swan and Canning River foreshores. This will provide a foundation

for sound development around the perimeter of the river system.

The current level of investment being made to address this issue is not maintaining

pace with the level of riverbank infrastructure deterioration, a problem exacerbated

by more frequent weather and tidal episodes. This is clearly not sustainable and can

only result in more serious incidents w ith more costly consequences.

The solutions described will tip the balance to a proactive and preventative

paradigm in which Western Australia can take full advantage of this unique and

valuable asset.

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8.0 BIBLIOGRAPHY

• Swan River Trust, 2007. Communit y Survey of Fut ure Values and Aspirations for

the Swan and Canning Rivers. Prepared by Research Solutions. Government of Western Australia

• Swan River Trust, 2007. Potent ial Impact s of Climate Change on the Swan and

Canning Rivers. Prepared by the Swan River Trust Technical Advisory Panel. Government of Western Australia.

• Swan River Trust, 2008. Swan and Canning Rivers Foreshore Assessment and

Management Strategy. Government of Western Australia, Perth.

• M P Roger & Associates 2005. Sir James Mit chell Park Foreshore Renovation

Plan. City of South Perth.

• M P Rogers & Associates 2008. Erosion Assessment Western Foreshore. City of

South Perth. • M P Rogers & Associates 2008. Sout h Pert h Foreshore - The Promenade. City of

South Perth. • M P Rogers & Associates 2008. Barrack St Jetty Riverwall Assessment. City of

Perth.

• M P Rogers & Associates 2005. Mount s Bay Road Inspect ion. City of Perth. • Tides WA, Department of Planning and Infrastructure October 2008. Tidal and

water level information • Tourism WA October 2008. Visitor numbers and revenue.

CONTACT DETAILS CLIFF FREWING,

CHIEF EXECUTIVE OFFICER

CITY OF SOUTH PERTH

SANDGATE STREET

SOUTH PERTH

WESTERN AUSTRALIA 6151

Ph: 08 9474 0777

Email: clifff@southperth.wa.gov.au