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  • Climate Futures TASMANIA

    Climate Futures

     

    Climate change is a feature of the 21st century. Making sensible choices on how we can adapt to climate change hinges on understanding what changes are likely, where they are likely, and when they will start to have a significant impact.

    ACE has developed world class climate science and modelling capability through its Climate Futures for Tasmania project. The project is possible with support through funding and research of a consortium of national and Tasmanian state partners.

    Climate Futures uses sophisticated climate modelling techniques and current knowledge to describe the most likely future climate scenarios for the state of Tasmania. The data generated better represents Tasmania’s geography and its effect on the local climate. The climate projections are computer-simulated and produce data to use in decision-making processes. Climate Futures interprets climate projections at a local scale, so that communities, industries and individuals can use information in their local planning and adaptation actions.

    The Climate Futures project details the general impacts of climate change in Tasmania over the 21st century, with a description of past and present climate and projections for the future.  It also looks at the impacts in the applied areas of water and catchments, assessing how water will flow through various Tasmanian water catchments and into storage reservoirs under different climate scenarios; and agriculture, assessing specific climate indicators most important for productivity in several key agricultural groups.  Finally, working with emergency service agencies, the project identifies the climate variables of greatest concern to emergency managers.

     

    View: Dr Tony Press discusses the Climate Futures project

     

    Projects and project leaders

    ·     Climate Futures for Tasmania: Professor Nathan Bindoff

     

    Read the Reports: download the full technical reports and their companion summaries:

    Climate Modelling technical report, summary

    General Climate Impacts technical report, summary

    Impacts on Agriculture technical report, summary

    Water and Catchments technical report, summary

    Extreme Events technical report, summary

    Severe Wind Hazard and Risk technical report

    Extreme Tides and Sea-Level Events technical report

    Our Partners: Find out more about our partners: Climate Futures for Tasmania is possible with support through funding and research of a consortium of state and national partners.

    Download: Contacts for Climate Futures for Tasmania

    Research Utilisation

    Data are being made available to many sectors of the community including state and local government, emergency services, water authorities, power companies, farmers, graziers, fruit growers, vignerons and researchers. The project scientists interpret these data to assist decision making, and the data are distributed in a format that assists their incorporation into decision-making and planning systems. The project will also provide an accessible basis for subsequent climate change research by archiving fine-scale climate model outputs for the entire state of Tasmania. ACE commercial participants use the Climate Futures data set to develop specific commercial products, for example a tool that identifies and communicates the risks that climate change poses for infrastructure.

     

    Climate change commentator Peter Boyer writes about the project here

     

    News story: Climate Futures research put to work

     

    News story: Research shines a light on new agricultural landscape

     

    News story: Rivers and catchments will change with the climate

     

    News story: New research projects increase in extreme weather events

  • Climate change impacts in Queensland’s regions

    Climate change impacts in Queensland’s regions

    Changes in the climate will affect Queensland’s regions in different ways. Early planning and preparation for these changes will help build regional communities to potential future impacts.

    In August 2009, the first set of regional climate change summaries was released to assist local government, business, industries, and the community prepare for future variability. Key findings from the regional summaries were that:

    • South East Queensland should prepare for challenges such as water shortages due to drier and warmer conditions
    • A rise in sea levels is likely to place coastal regions at increased risk of inundation, erosion, and damage to buildings and infrastructure
    • Far North Queensland is likely to experience fewer but more intense rainfall events and tropical cyclones

    Central-west and south-western Queensland are projected to experience the greatest warming and a strong decline in rainfall.

    Regional summaries

    Climate Commission: The Critical Decade – Queensland climate impacts and opportunities

    • Information on climate change impacts on Queensland’s agricultural, tourism, property and lifestyle are covered in the Climate Commission’s 2012 Queensland reportExternal link icon ( http://climatecommission.gov.au/report/queensland-climate-impacts-opportunities/ )

    CSIRO’s Queensland’s biodiversity under climate change: impacts and adaptation – synthesis report

    • This 2012 reportExternal link icon ( http://www.csiro.au/Organisation-Structure/Flagships/Climate-Adaptation-Flagship/Queensland-biodiversity-under-climate-change.aspx ) is a synthesis of the existing scientific research on climate change impacts and the adaptation options for terrestrial, freshwater aquatic, coastal and marine biodiversity, it’s ecosystems and the services they provide. The report summarises the different ways climate change is likely to affect biodiversity ecosystems, and ecosystem services in Queensland.

    * Requires Adobe Reader ( http://www.ehp.qld.gov.au/help/pdf.html )

    Last updated
    23 April 2013

  • Victoria Climate change impacts in Vic.

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    Victoria Climate change impacts in Vic.

    Potential impacts and costs

    Victoria is Australia’s smallest yet most densely populated and urbanised mainland state. It is the second most populous Australian state with approximately 5.6 million people. Melbourne is Victoria’s largest city, home to more than 4 million people.

    Victoria contains many diverse environmental regions, ranging from the wet, temperate climate of Gippsland in the south-east to the snow-covered alpine areas in the north-east. There are also extensive semi-arid plains to the west and north-west of the state.

    The following information highlights some of the potential impacts and costs to the state’s industries, infrastructure, environment and people from climate change.

    Coastal zone

    Climate change will lead to sea level rise which will impact on coastal settlements, infrastructure and ecosystems. Between 31,000 and 48,000 residential buildings, with a current value of between $8 billion and $11 billion may be at risk of inundation from a sea level rise of 1.1 metres. A 1.1 metre sea level rise will also put up to 3500 kilometres of Victoria’s roads, up to 125 kilometres of railways and up to 2000 commercial buildings at risk. These assets have an estimated value of up to $9.8 billion, $500 million and $12 billion respectively.

    Global sea levels increased by 1.7 millimetres per year over the 20th century. Over the past 15 years, this trend has increased to approximately 3.2 millimetres per year. This rate varies significantly around Australia. Since the early 1990s, the Victorian coast has experienced increases of between 2.6 and 2.8 millimetres per year.

    In 2009, the Australian Government produced the report, Climate change risks to Australia’s coasts, followed in 2011 by an update to this report entitled Climate change risks to coastal buildings and infrastructure. For a visualisation of the potential sea level rise, the department has also produced a series of maps.

    Water supply

    Much of Victoria lies within the Murray Darling Basin region where climate change is likely to have serious impacts on water resources. Projections indicate a 13 per cent reduction in average surface water availability in the south of the Murray Darling Basin as a median outcome by 2030. The reduction would be greatest in the south-east where the majority of runoff is generated and where the impacts of climate change are expected to be greatest.

    In Melbourne the average long-term stream flow into water supply catchments could be reduced by up to 11 per cent by 2020, and as much as 35 per cent by 2050.

    Extreme events

    The average annual number of days above 35 degrees Celsius is likely to increase from 9 days currently experienced in Melbourne to up to 26 days by 2070 without global action to reduce emissions. In Mildura, days above 35 degrees Celsius may increase from 32 days currently to 76 days under the same scenario.

    Parts of Victoria are likely to experience increased bushfire risk due to higher temperatures and drier conditions. For example, in Bendigo the number of days experiencing high or extreme fire weather is predicted to increase from 18 days to 30 days annually by 2050, and Mildura is expected to face up to 107 days of very high or extreme fire risk by 2050, up from 80 days currently experienced.

    Human health

    As the number of very hot days (above 35 degrees Celsius) increases and heatwaves become more frequent, more people may suffer heat-related illnesses and death, with the elderly particularly vulnerable. An estimated 289 people aged 65 and over die annually in Melbourne from heat-related deaths (1997-1999 average). This could potentially rise to between 566 and 604 a year by 2020, and between 980 to 1318 by 2050.

    The population of Victoria is more susceptible to cold-related deaths than heat related deaths. As such the total number of temperature-related deaths are projected to be up to 1164 in the year 2100 with no mitigation, compared to 1966 in a world with no human induced climate change.

    During the January 2009 heatwave there were 374 more deaths (an increase of 62 per cent) than would be expected based on the average over the previous five years, with the greatest number of deaths occurring in people 75 years or older.

    Natural environments

    Victoria’s unique alpine ecosystems host a variety of plant and animal species, many of which are endangered. Species such as the Mountain Pygmy Possum that occupy habitat at the highest elevations and in the coldest environments will have nowhere to retreat as the climate warms. A 1°C temperature rise could dramatically decrease the entire climatic habitat of this small mammal.

    A reduced snow cover of 10 to 40 per cent relative to 1990 by 2020 is projected, which would have significant consequences for alpine tourism in Victoria. Alpine resorts are economic drivers for surrounding communities and a reduced ski season and diminished snow cover is likely to have negative economic impacts for the Australian ski industry.

    Under an extreme emissions scenario with increased warming and decreased rainfall, the length of the snow season may decrease by up to 96 per cent by 2050, with a dramatic reduction in snow depth. Snow cover at Mt Hotham (where the highest elevation is 1882 metres) could reduce from 129 days currently down to between 21 and 114 days by 2050.

    The Little Penguins found on Phillip Island have been shown to be particularly vulnerable to fire over the past few years. In coastal regions, misty rain or fog following long spells of hot, dry and dusty weather can result in the ignition of power pole cross arms, due to a build-up of salt and dust on the insulators. The red-hot salt crust can fall from the pole and ignite vegetation at its base. In recent years a number of such fires have occurred on Phillip Island, resulting in death or injury of a large number of penguins. Increased occurrence of hot, dry and dusty weather is projected for the future and may result in increased fire-related risk of Little Penguin death and injury on Phillip Island.

    Agriculture

    Potential changes in climate may reduce productivity and output of Victoria’s agricultural industries in the medium to long term.

    While wheat producers may benefit from carbon dioxide fertilisation with modest levels of warming, yields are likely to decline under more extreme warming scenarios. For example, in the region of Birchip, yields may drop by more than 20 per cent by 2100 in the absence of mitigation.

    ABARE modelling (2007) estimates the following declines in agricultural production for Victoria compared to a world with no human-induced climate change.

    Approximate decline in production by 2030 and 2050
    Approximate decline in production by 2030 (%) Approximate decline in production by 2050 (%)
    Wheat 9.6 13.4
    Beef 2.4 6.5
    Sheep 7.1 12.9
    Dairy 4.6 10.0

    Adaptation

    Given the state’s high vulnerability to projected climate change, it is important that appropriate actions are taken by government, businesses, communities and individuals to ensure effective adaptation is possible in a changing environment.

     

       

  • WA beaches, parks, to ‘disappear’ by 2100

    WA beaches, parks, to ‘disappear’ by 2100

    Date
    May 24, 2011

    Courtney Trenwith

    Perth's waterfront areas face a perilous future if sea-level rise forecasts come true.Perth’s waterfront areas face a perilous future if sea-level rise forecasts come true.

    The Kwinana Freeway and Perth’s riverside roads will flood every two weeks and parks and beaches including Cottesloe will disappear by 2100, according to sea-level rise predictions released by the federal government’s Climate Commissioner yesterday.

    The commission’s report The Critical Decade has found sea levels around Australia’s west and far north have risen the most, with an eight millimetre rise recorded since the early 1990s.

    We’re predicting that it will start having an effect in the next 30-40 years. We have to do something about it.

    The figure is much higher than the United Nations’ 2007 forecast of 59 centimetres but below the 0.9-1.6 metres predicted by the Arctic Monitoring and Assessment Program earlier this month.

    Professor Chari Pattiaratchi from the University of Western Australia’s Oceans Institute said a sea level rise of one metre by 2100 was now the accepted measurement among climate change scientists.

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    Such a rise would have profound impacts on the tidal range along the West Australian coast. Each centimetre of sea-level rise causes approximately one metre of beach erosion, meaning that the coastline can be expected to move 100 metres inland.

    “Our tidal range in the South-West is about 0.6 metres, so one metre is quite large compared to our tidal range. It’s quite a significant [change],” Professor Pattiaratchi said.

    The highest tide recorded in WA was 1.98 metres in 2003, he said.

    Professor Pattiaratchi said if the sea rose one metre, the present record level would be recorded almost every two weeks, causing estuaries to flood and beaches to erode.

    “Rivers which already experience a lot of erosion and cause problems would get much, much worse,” he said.

    In particular, Cockburn Sound off Rockingham, coastlines in northern Mandurah and along the Busselton region and the Swan River in Perth would “flood every couple of weeks”.

    Limestone reefs at Cottesloe Beach would be the only thing preventing seaside homes from flooding as the beach disappeared.

    Professor Pattiaratchi said Kwinana Freeway and Riverside Drive also would regularly flood, similar to flash flooding last Friday when 20 millimetres of rain fell in just 40 minutes during peak-hour, and parks throughout the city would be consumed by water.

    “We’re predicting that it will start having an effect in the next 30-40 years,” he said.

    “We have to do something about it.”

    WA climate scientists have claimed adaption was the only way to avoid sea-level rise impacts because natural increases in greenhouse gas emissions were comparable to the level emitted by humans, meaning a reduction in practices such as the burning of fossil fuels was too late.

    As an example, Director of the Centre for Water Research at UWA, Professor Jorg Imberger, said a barge at Fremantle could save the suburb.

    “The water level rise within the city is manageable without too much money,” he said.

    “But the thing that won’t be is the big impact on the lifestyle of Perth – beaches would be gone. We’ve built roads next to the beaches so the sand dunes can’t migrate.

    “There will be increased humidity, that means dengue fever and malaria would be coming down to Perth. So it’s not good.

    “And there’s no action that can be taken [to prevent the sea level rise] … people just aren’t able to respond [quick enough]. The only thing is adaption.”

    Professor Imberger said on a positive note, WA was well positioned to make long-term impacts on rainfall and potentially become carbon neutral.

    “We could revegetate some of the South-West to give the farmers back some rain,” he said.

    “We could better manage Lake Argyle [in the Kimberley] and stock it with fish and aquaculture. That would increase the net primary production in the lake, which potentially could sequent 30 per cent of emissions.

    “Third, we could take a really hard look at the resources industry and the money that’s being made from that is predominantly going overseas. We could use those earnings to really get ahead in a very positive way.

    “With a bit of will WA could lead the world in sustainable living.”

    twitter Follow WAtoday on Twitter @WAtoday

    Read more: http://www.watoday.com.au/environment/climate-change/wa-beaches-parks-to-disappear-by-2100-20110523-1f0ks.html#ixzz2UYy78lVw

  • You know something is deeply wrong when kids no longer quote player statistics, they quote betting odds.

    Dear Inga ,

    You know something is deeply wrong when kids no longer quote player statistics, they quote betting odds.

    Just like overpriced pastry goods and a crowded train ride home, taking the kids to the footy is now inextricably linked with exposure to gambling. Whether it’s constant updates on live odds or watching Tom Waterhouse sign autographs at half time, seeing gambling in sport is unavoidable. Kids can’t even watch the game at home without being inundated by ads urging people to have a punt.

    You may have seen that yesterday the Government outlined a plan to ban broadcasting of odds and gambling ads during play. It’s a great start. But tomorrow the ALP Caucus is meeting to debate a suggestion by Stephen Jones MP that would flat-out ban all gambling advertising during all sports broadcasts except for horse racing and the greyhounds. Even better!

    What MPs hear from their local constituents today could really tip the balance tomorrow. What will their staff advise your MP before the meeting tomorrow? How about: “Boss, seriously, we got 600 emails about that yesterday. Voters would love it if we went further!”

    You know what to do. Click the below link to contact your local ALP MP or Senator before tomorrow’s debate:

    http://www.getup.org.au/sport-without-gambling

    Since the start of the footy season, bookmaker Tom Waterhouse has increased his TV advertising budget by 340%. [1] Parents and communities are taking notice and have made it clear that it’s time our sports are cleaned up and rid of gambling’s insidious presence.

    It’s thanks to tireless campaigning from communities and leaders around Australia that we’ve even gotten this far. A full ban is supported by tireless gambling crusaders like the Rev. Tim Costello, and is being championed in Canberra by Independent Senator Nick Xenophon, Andrew Wilkie MP and the Greens’ Senator Richard DiNatale. It’s also backed by South Australian Premier Jay Weatherill.

    Will you ask Caucus members to deliver real reform, and take Australia’s great sporting codes back from the gambling companies?

    http://www.getup.org.au/sport-without-gambling

    GetUp members have rallied to protect vulnerable members of our society from exploitation by the gambling industry many times before, whether by diving the national ‘Stop the Loss’ campaign for pokies reform, lobbying to limit pokies bets to $1 a spin, and forcing Woolworths – Australia’s largest poker machine owner – to confront the issue by holding an Extraordinary General Meeting. Sports gambling advertising could lead to a new generation of problem gamblers unless we speak up now.

    Despite what we’ve seen in recent months, gambling has never been a central feature of any code of football, nor should it be.
    Let’s beat the odds and ban the ads.

    Thanks for all that you do,
    Erin, for the GetUp team.

    GetUp is an independent, not-for-profit community campaigning group. We use new technology to empower Australians to have their say on important national issues. We receive no political party or government funding, and every campaign we run is entirely supported by voluntary donations. If you’d like to contribute to help fund GetUp’s work, please donate now! If you have trouble with any links in this email, please go directly to www.getup.org.au. To unsubscribe from GetUp, please click here. Authorised by Sam Mclean, Level 2, 104 Commonwealth Street, Surry Hills NSW 2010.

  • Impact of coastal erosion in Australia

    Impact of coastal erosion in Australia

     

    As a follow up to the Impending Coastal Crisis feature we posted earlier this week, Senior Coastal Scientist at Coastalwatch Professor Andrew Short has compiled a comprehensive piece focusing on coastal erosion in Australia.

    For the 50% of the Australian coast that is composed of sand and in some places mud, the shoreline is prone to change, building seaward and in some places eroding landward. In most locations this is a natural process with usually no impact on human settlement. Coastal protection of the shoreline is rarely required in Australia, however in a few locations the dynamic shoreline has become a problem, in some cases a major and expensive problem, and in almost all of these cases the problem is related to human interference or encroachment on the shoreline. Coastal protection works, such as breakwaters, groynes, or seawalls, are usually built to guard against erosion. In doing so they harden the coast and reduce its ability to adjust naturally. As a consequence, these defences can exacerbate further erosional problems, with seawalls reflecting and concentrating wave energy and erosion, and groynes starving downdrift the coast of sediment thereby leading to further erosion. There are areas where human have encroached into the dynamic beach environment only to suffer the consequences, and others where they have interfered with coastal processes leading to accelerated coastal erosion.

    Sand dredging at Currumbin Photo: Bartles
    Much of the shoreline of the rapidly expanding tropical city of Cairns appears especially vulnerable. The popular marina area and the hub of Cairns has encroached on Trinity Inlet and formerly mangrove-covered mudflats along the seafront are now bare and lined with seawalls, backed by development close to sea level. Much of Cairns is also built on a coastal plain, part of the Barron River delta, with the mangrove-lined tidal creeks that meandered through these plains all that remain. These are inundated at highest tides and demonstrate that critical infrastructure, such as the airport, lie close to present high tide level (as is often also the case with other airports, such as those at Brisbane and Sydney). At this level much of the coastal plain and city would be inundated by a 2.5 m storm surge calculated to accompany a 1 in 100 year storm, whereas dating sequences of coral rubble ridges deposited by large storms on nearby islands indicate that considerably larger events than those known from the past 200 years have recurred frequently over past millennia. The north Cairns coast along Yorkys Knob-Machans-Holloway beaches is lined with seawalls because much of the shoreline has been retreating, on a coast that in the long-term is building seaward as the Barron River delta progrades. The problem here is both the dynamic shoreline of the delta, which switches channels, has major floods and accompanying pulses of sediment, on a coast exposed to periodic tropical cyclones, all of which produces a highly dynamic shoreline. Roads and houses have been built on parts of the coast which will periodically be reclaimed by the sea, as well as periodically protected by wide beaches. Finally, when climate change is considered, the already perilously low-lying developments in Cairns are at considerable risk to inundation, as discussed in the next section.

    Cairns waterfront – low, eroding & vulnerable
    Australia’s best known strip of defended coastline, and a major holiday destination for local, national and international tourists, is the 35 km between the New South Wales-Queensland border at Point Danger and the Nerang Inlet, better known as the Gold Coast.

    Here is a system that is part of a northerly conveyor belt of sand moving north from New South Wales across the border at a rate estimated at 500 000 m3/yr. In 1962-64 the Tweed River training walls were extended for navigation, 400 m out to sea. The southern wall blocked the movement of sand, which built out the adjacent Letitia Spit by 250 m, in the process trapping millions of cubic metres of sand and preventing it from moving across the border and along the Gold Coast beaches.
    As the sand supply was depleted, combined with a series of severe cyclones (Dinah, Barbara, Dulcie, Elaine and Glenda) in 1967, 8 million cubic metres of sand was eroded from the beaches and threatened the backing Gold Coast roads, houses and hotels. The solution has been threefold. First a continuous terminal seawall was built the length of the coast and covered with sand and dunes. Second between 1995 and 2000 3.5 million cubic meters of sand was dredged from the Tweed Bar and placed offshore of the southern Gold Coast beaches. Third, a permanent pumping system was built just south of the training wall, which since 2000 has pumped more than 500 000 m3 of sand each year from New South Wales across the border onto the Gold Coast beaches. In 2007 these beaches were as wide was they have ever been. However it has all come at a cost in the tens of millions of dollars.

    Sand pumping at Cooly/Tweed Photo: Bartles
    A similar training wall built between 1960-66 at the mouth of the Brunswick River, 50 km to the south, to service the small fishing fleet. Studies have shown that the walls impacted the beach to the north and south. The beach built it out for 8 km updrift, while erosion was observed to extend up to 17 km downdrift, with the shorelines not stabilising until 1987. The largest impacts were close to the wall with the small beachfront community of Sheltering Palms, located 2 km north of the wall, experiencing up to 90 m of shoreline erosion which resulted in some houses, roads and telegraph poles ending up in the surf zone and finally abandonment of the entire village by the mid 1970’s. Unlike the Gold Coast, this area did not warrant the massive expenditure on protection, so it was sacrificed.

    Bruns river mouth Photo: Dan Wyer
    Coastal erosion, particularly associated with a cluster of east coast cyclones, has occurred at several points along the New South Wales coast. Dressing sheds at Manly were broken up by waves in 1913 and the North Steyne SLSC in Manly was severely damaged in 1950. The jetty at Byron Bay was removed in 1972, and ad hoc coastal protection was attempted at Belongil Spit with car bodies dumped to try to halt the erosion of sand. The 1974 storms, estimated as a 1:200 year event, destroyed the harbour side Manly pier and resulted in loss and damage of property and roads being cut at several points along the Sydney and south coast; elsewhere they were the first stage of erosion, with subsequent storms actually undermining property, as with the three houses that were destroyed during a storm in 1978 at Wamberal.

    NSW Wamberal Beach 1978, three house fall into sea Photo: Andrew Short
    Wamberal Beach Photo: Andrew Short
    Collaroy Beach on Sydney’s northern beaches is a classic example of inappropriate planning and shoreline subdivision that took place more than 100 years ago. The original property boundaries extend, and still do, down across the dune onto the beach, with most of the houses and now some high rises built on the beach-dune area. The consequences were entirely predictable, every time the beach retreated during high seas, the then beach shacks were undermined. Major erosion occurred in 1920, seven shacks fell into the sea in 1944-5, and one was washed out to sea in 1967. Following the 1945 storms the council voted to resume the remaining houses. Instead, within ten years the first block of flats was built and soon after the first high-rise, which in turn was undermined by the 1967 storms. More high rises followed, the next built just in time to be undermined by the 1974 storms. Here the council has allowed initial development in a hazard zone, and later massive over-development even after houses had been washed away. Collaroy remains a problem area with most of the affected properties fronted by makeshift seawalls. The council has started slowly buying back some properties and hopes the state government will allow massive beach nourishment at some time in the future. In the meantime every big sea removes the narrow beach and exposes the unsightly and hazardous seawalls on one of Sydney’s premier beaches.

    Wetherill St Collaroy/Sth Narrabeen. Real estate potentially threatened. Photo: Andrew Short
    Warilla Beach just south of Port Kembla was sacrificed to protect a row of low cost houses. Like Collaroy the houses had been built too close to the shoreline on the formerly active foredune. The volume of sand on the beach, already depleted through mining for export in the 1960s, was further reduced because longshore processes carried a proportion into the entrance to Lake Illawarra when the entrance lay to the south of a tombolo connected to an offshore island. Any sand returned by tidal processes leaked onto Perkins beach to the north when the tombolo closed off Warilla Beach, acting as a trapdoor. Finally when the 1974 storms threatened the houses, the council responded by building a rock seawall along the southern half of the beach, replacing the public beach with rock, even the surf club had to be moved. This example of poor planning has only been remediated recently when further works at the lake’s entrance, in an effort to keep it permanently open, led to significant nourishment of the beach. A series of storms generated by east coast lows in June and July 2007 however severely truncated the beach as the sand was being pumped south, providing an ominous warning of the likely long-term fate of the rebuilt beach.

    Warrilla – seawall built the length of beach, surf club had to close and move Photo: Andrew Short
    The rocky shores of New South Wales appear much more resistant against erosion. Locally however there are concerns about rock falls and public safety, as at Bilgola, Newport and Narrabeen headlands in Sydney. An exception is the steep cliffs at Coalcliff, first named by Flinders and Bass, where landslides are associated with the claystones and shales that are interbedded with the sandstones. The continual damage to Lawrence Hargrave Drive and the threat of falling rocks, led to the construction of the spectacular Seacliff bridge, a 665 m stretch of road that is built out from the cliff face over extensive rock platforms.
    Most of the Victorian coast is protected by a foreshore reserve, however at Portland the reserve was not wide enough to protect a stretch of beach known as the Dutton Way. Here problems started when a breakwater was completed in 1960 to expand the port of Portland, thereby interrupting the easterly movement of sand to the downdrift Dutton Way beach. As the beach began retreating threatening a road a seawall was commenced in 1970. Since then the wall has continue to follow the erosion to the east and now winds it way along the shore for 4.5 km. Low-lying areas around the Gippsland lakes are subject to flooding, particularly after the artificial opening of the Gippsland Lakes in 1889. Flooding in 2007 after intense rainfall over the catchments that drain into the lake was exacerbated at high tide and inundated much of Lakes Entrance.

    Dutton Way at Portland, the seawall just keeps growing Photo: Andrew Short
    Dutton Way, Portland Photo: Andrew Short
    The Adelaide metropolitan beaches have been experiencing erosion for decades, as a result of the natural 40,000-50,000 m3/yr northerly sand transport, exacerbated by dieback of nearshore seagrass meadows as a consequence of sewage pollution; and further aggravated by some roads and structured located too close to the shore. The erosion has been managed both by the construction of 14 kilometres of seawalls and the trucking of sand from the northern end of the system back to the south, and more recently pumping sand onshore from nearshore sand deposits. Maintenance of these metropolitan beaches continues at significant cost; but it has been possible to sustain the natural values of the coast, even re-establishing dunes in front of the esplanade at Brighton.

    Adelaide beaches – eroding & protected by seawalls & nourishment Photo: Andrew Short
    In a political decision that will ensure South Australia has generations of coastal problems the South Australian government in 1990 voted to freehold hundreds of beach shacks, many built close to or on the beaches and in low lying erosion and flood-prone areas. Now the shacks are freeholded it will be up to the government and taxpayers to maintain these unsightly ribbon developments and to try and protect these properties as they become increasingly exposed to shoreline erosion and sea level rise.

    Lucky Bay – typical of the poorly sited shacks, now freeholded Photo: Andrew Short
    In contrast the Western Australian government has been successively removing the many hundreds of beach and fishing shacks that dotted the coast north of Perth as far as Geraldton. These have been removed along with the associated myriad of 4WD tracks and replaced by coastal reserves with well planned and designed access points along the coast, while neighbouring coastal towns are being developed as nodes for the increasing coastal population. Western Australia’s Geographe Bay is a relatively sheltered sandy embayment with a northerly drift of sand from Busselton north to Mandurah.

    Port Geographe canal development etc near Busselton and all the ensuring accretion seagrass (arrow) and erosion on north side (arrow) road and houses threatened Photo: Andrew Short
    In the early 1990s this northerly drift was interrupted by the construction of a series of training walls and groynes associated with a canal estate called Port Geographe. Not only sand but also piles of rotting seagrass built out 100 m against the updrift wall, while the beach on the northern side eroded back 250 m, threatening a road then houses. A combination of makeshift seawall and sand bypassing has been used with limited success; meanwhile the rotting seagrass continues to pile up and waft across the development. Just 120 km further north the Port Bouvard development built a similar training wall, but also added a permanent sand bypassing system, the result, no uplift build up and no down drift erosion.

    Port Geographe Photo: Andrew Short
    These few examples serve to illustrate that the coast is a dynamic and at times very inhospitable environment. When we develop the coast it is essential that we first understand the nature processes and hazards, including longterm rates of shoreline movement and change, and extent of inland erosion and inundation. We must then plan with this information in mind, so that no inappropriate structures or development are placed in this hazards zone, and if they have to be such as ports and airports, then they are properly defended. Likewise if we interrupt the long-shore movement of sand we need to make contingencies such as sand bypassing, otherwise nature will realign the shores and place any down-drift development at risk.

    – Professor Andrew Short, Senior Coastal Scientist, Coastalwatch

    Read more: http://www.coastalwatch.com/news/article.aspx?articleId=4524#ixzz2UYlkHxYz