Focus Area 5A3 Issues in Australian Environments Coastal management
Syllabus: Coastal Management • Students learn about: At least TWO geographical issues affecting Australian environments,(one study must include fieldwork): • the geographical processes relevant to the issue • the perceptions of different groups about the issue • individual, group and government responses to the issue • decision-making processes involved in the management of the issue • management of the issue and implications for sustainability, social justice and equity
Syllabus: Coastal Management • Students learn to: • explain the interaction of the physical and human elements of the environment • recognise the responsibility of the levels of government to the issue • propose actions that promote: • sustainability • social justice • equity • evaluate the success of individuals, groups and the levels of government in managing the issue
The geographical processes relevant to coastal management • Atmospheric processes – caused by such elements as temperature change, storms and the force of the wind. • Biotic processes – plant and animal life and the way they interact. • Geomorphic processes – uplifting forces within the Earth’s crust, which create sea cliffs or the forces of erosion and deposition. • Hydrologic processes – action of the waves, the tides and ocean currents.
Hydrological processes - waves • The sea is a powerful force whose constant action can change the shape of coastlines especially the shoreline where the land borders the sea. • The size of waves depends on two things: • The strength of the wind. • The fetch • The fetch is the distance a wave travels. The greater the fetch, the larger the wave. • The stronger the wind the larger the wave. A wave slows as it approaches a beach. • This is the result of friction between the water and the beach. This causes a wave to break. Activity: What determines the size of waves on the shoreline?
Hydrological processes – waves continued • When waves enter shallow water the energy in the wave starts to interact with the sea floor. • The wave peak eventually travels faster than the wave base causing the wave to break. A broken wave forms the surf and swash zone.
Swash and backwash continued • When a wave breaks on a beach you can observe the swash and backwash. The swash moves up the beach at an angle, the backwash returns by gravity straight back to the sea.
Swash and backwash • The action of swash and backwash mean the grains of sand can move in a zig-zag motion along a beach. This is known as longshore drift. • In stormy weather the action of waves is more destructive hence strips beaches of sand. Over time beaches will build up again as wave action deposits the sand back on the beach.
Waves - definitions • Swash - the movement of waves up the beach • Backwash - the movement of waves returning back to the sea • Long shore drift - the movement of water parallel to the shoreline caused by swash and backwash
Two main types of waves • Constructive waves • These waves build beaches. • Each wave is low. • When a wave breaks it carries material up the beach in its swash. • The beach material will then be deposited as the backwash soaks into the sand or slowly drains away. • These waves are most common in summer.
Two main types of waves 2. Destructive waves • These waves destroy beaches. • The waves are usually very high and very frequent. • The back wash has less time to soak into the sand. • The continual hitting of waves on the beach means there is more running water to transport the material out to sea. • These waves are most common in winter.
Hydrological processes - tides • At the beach you can observe high and low tides. Tides can be checked in the newspaper daily and on a tide chart. • Tides are caused by the gravitational pull of the moon and the sun on the ocean surface. The moon’s pull is much stronger than the sun’s but both can work together. • The difference in height between the high and low tide is called the tidal range.
Activity - Hydrological processes – Tides • Identify what a tide is. • Use a diagram to explain how a tide is caused. • Describe the meaning of the term ‘tidal range’ • Look up a tide chart in the Sydney Morning Herald for Sydney Tides. • When was high tide yesterday? • What was the height?
Geomorphic processes - erosion • Erosion is destructive waves wearing away the coast. • Erosional features mainly occur around headlands. • They are shaped by three main processes • Hydraulic action • Corrasion • Corrosion
Geomorphic processes – erosion continued • Hydraulic action – • Waves crash against a headland. • When waves hit the base of a cliff air is compressed into cracks. • When the wave retreats the air rushes out of the gap. • Often this causes cliff material to break away. • Blowholes are a common feature formed by hydraulic action.
Geomorphic processes – erosion continued • Corrasion / Abrasion – • Waves crash over rock shelves. • When waves pick up beach material (e.g. pebbles) and hurl them at the base of a cliff. OR • Wave action moves rock and other material across the rock shelf • Both wear away the rock in an abrasive fashion much the same way as sandpaper can smooth a piece of wood.
Geomorphic processes – erosion continued • Corrosion / Solution – • When certain types of cliff erode as a result of weak acids in the sea. • In rocks along the coast there are minerals like iron. • When waves break they wet the rocks. As the rock dries the salt in the sea water crystallises and acts on the minerals in the rock to erode.
Erosion of a headland • A headland is an area of hard rock which sticks out into the sea. • Headlands form in areas of alternating hard and soft rock. • Due to the different nature of the rock erosion occurs at different rates. Less resistant rock (e.g. boulder clay) erodes more rapidly than less resistant rock (e.g. chalk). • Where the soft rock erodes bays are formed either side of the headland. • As the headland becomes more exposed to the wind and waves the rate of its erosion increases. • When headlands erode they create distinct features such as caves, arches, stacks and stumps.
The sequence in the erosion of a headland • Stage 1 - Waves attack a weakness in the headland. • Stage 2 - A cave is formed. • Stage 3 - Eventually the cave erodes through the headland to form an arch. • Stage 4 – The roof of the arch collapses leaving a column of rock called a stack. • Stage 5 - The stack collapses leaving a stump.
The Twelve Apostles Activity: Imagine you are a park ranger employed at Port Campbell National Park. Prepare a brief talk including a visual presentation that explains the formation and eventual destruction of the Twelve Apostles. Include: Location of Twelve Apostles How the Twelve Apostles were formed What was London Bridge? What happened to it?
Geomorphic processes - deposition • Deposition is when eroded material including sand and sediment is dropped by constructive waves. It happens because wave have less energy. Deposition creates a range of landforms.
Geomorphic processes – Deposition - Beaches • The beach is the area between the lowest spring tide level and the point reached by the storm waves in the highest tides. • Every beach is different but they are made from the accumulation 0f sand along the shoreline formed from eroded rock and shell material. • During storms large quantities of sand are deposited offshore forming sand bars which help limit the impact of erosive waves. • The removed sand is eventually returned naturally by smaller constructive waves returning the beach to its former state.
Geomorphic processes – Deposition – Spit • Long shore drift moves material along a coastline. • Where there is an obstruction or the power of the waves is reduced the material is deposited. • Where rivers or estuaries meet the sea deposition often occurs. • The sediment which is deposited usually builds up over the years to form a long ridge of material, often sand. This is called a spit. • Spurn Head on the Holderness Coast the East Coast of England is an example of this feature.
Geomorphic processes – Deposition – Coastal dunes • Coastal dunes are formed by the action of the wind. • Once sand is deposited on the beach it can be transported by wind. Sand is blow landward and trapped by low-lying vegetation like coastal spinifex. • The fore dune is a store of sand which may be eroded away or may continue to increase in size. • The fore dune provides a buffer zone for the fragile dune vegetation located on the hind dune as well as property and developments. It does this by absorbing heavy wave action during storms then rebuilding and restabilising quickly ready for the next period of heavy wave action. • Plant communities can quickly recolonise and stabilise the area after periods of erosion, allowing the dune to form again.
Activity – Newspaper Article • The local council has decided to buy back residential property located on a headland and a neighbouring fore dune that is subject to severe erosion. • Local residents who own the property say the council is depriving them of their spectacular views, relaxed lifestyle and valuable property. • Write a newspaper article that evaluates the council’s decision to buy back the properties. • The article should present facts and consider a range of opinions about the issue. • The article needs to include an opinion on the property buy-back proposal.
Biotic processes – plant and animal life • On the shore plants are typically low and tough as they have to survive the onshore winds and salt spray. • Sometimes plants are introduced to stabilise dunes, which can move or be washed away. Plants like the bitou bush (shown below), a native of South Africa, has become a pest and has overrun large areas along the east coast of Australia. Programs to eradicate, get rid of, bitou bush have begun.
Biotic processes – plant and animal life • In the water there are many varieties of sea grasses and seaweed. • There are also giant kelps, large brown algae that grows just below the low tide mark in dense beds. Kelps (illustrated above) absorb wave action and help defend the shoreline against storms.
Biotic processes – plant and animal life Animal life consists of - beach worms, - planktons (shown above) and - crustaceans (prawns, crabs (shown opposite) and lobsters) which provide food for fish. Small fish are food for sea birds and larger fish.
Activity – Geographical processes • Develop a collage defining and illustrating the geographical processes relevant to coasts. Include the following: • Biotic processes • Geomorphic processes and • Hydrologic processes
Environmental impacts on coasts • This involves • Considering the perceptions of different stakeholders • Assessing the decision making process by considering • The way the situation has been managed and • Reviewing responses the process of management has received • Evaluating the entire process in terms of how it reflects upon Australia's level of sustainability, social justice and equity.
Australia’s Coasts • In comparison with many countries of the world, Australia possesses an enormous continuous coastline. • Australia's coast including islands stretches for about 60 000 kilometres and comprises over 10 000 separate beaches. • About two-thirds of the population live in the towns and cities that have been built to take advantage of the many benefits the coastline brings.
Human impacts on coasts – Perceptions of different stakeholders • Stakeholders or groups with an interest in coasts include: • Housing residents • Environentalists • Governments • Community members • Boat owners • Miners • Tourists
Housing and development • This involves: • Construction of houses around lagoons and swamps. • The use of wetlands for landfills. • The development of sand dunes for 'prime' real estate. • Recreational purposes have all had negative effects on Australia's coastal areas. • The removal of vegetation has: • Seen a significant reduction in biodiversity • Disrupted the natural processes which form intricate coastal ecosystems.
Housing and development – Beaches • Beaches are formed by an ongoing cycle of erosion and deposition of sand. Storms erode beaches of their sand, which is then re-deposited by large waves. • When humans use beaches for housing and recreation: • The natural cycle is interrupted and sand banks become depleted. • Over time beautiful beaches are destroyed. • Cliff-top housing, although aesthetically pleasing for home-owners, is also dangerous because of its interference with these natural processes.
Ports and marinas • To enhance the navigational potential of coastline, natural channels are widened or deepened by removing earth from the bottom of waterways (a process known as dredging). • This destroys the habitats of benthic (bottom-dwelling) organisms that live in the sediment that is removed. • Stone breakwaters stretching far out to sea are constructed around ports and marinas to reduce wave impacts and tidal fluctuations. • This has the negative consequence of hindering natural erosion and mineral deposition processes.
Stormwater run-off and pollution • Vast areas of land covered in concrete and bitumen, particularly in cities, generate enormous amounts of contaminated storm water and rainwater run-off. • This pollutes our waterways and damages fragile coastal ecosystems. • In addition petroleum-related pollutants are emitted from motorboats, ferries and large ships (20-30 per cent per cent of all marine pollution).
Sand mining • In Queensland, northern New South Wales, parts of Western Australia and South Australia, certain minerals found in beach sand are mined for the production of paints and industrial tools. • Sand minerals include zircon, ilmenite and rutile. In some areas of WA, calcareous sand beneath seabeds is also mined for the production of limestone and cement. • Australia has the world's largest Economic Demonstrated Resource (EDR) of these mineral sands and they are an important source of export earnings. • Extraction of sand minerals requires quarrying of beaches, which disrupts the natural cycles that form sand banks and destroys the habitats of many plants and animals.
Recreation and tourism • Coastlines have experienced the construction of high-rise resorts, shopping esplanades, playgrounds, golf courses and beach car parks. • Development has enhance the lifestyles of residents and the holiday experiences of domestic and overseas tourists but cause significant damage to Australia's precious coastal areas. • In less-frequented areas, the use of sand dunes for recreational purposes (for example four-wheel driving) damages sand dune formation and scares away wildlife.
Activity – Develop an imovie to outline the perceptions of different stakeholders to coastal environments Outline - what are the main features of : • Views of different stakeholders: • Housing residents • Environmentalists • Governments • Community members • Boat owners • Miners • Tourists
Effective management strategies require consideration of the often competing interests, attitudes and values of all stakeholders. • In Australia, it has become increasingly apparent that the community, private and government (including local, State/Territory and federal) sectors must integrate their efforts to better utilise, manage and protect the environment. • Adopting an integrated approach helps to ensure that environmental management outcomes are sustainable, socially just and equitable.
Stakeholders in environmental management issues • At the government level (also known as the public sector) • The Federal or Commonwealth Government • The State and Territory governments, and • Local governments (also called local councils). • Power over management and decision-making processes is divided between these three tiers (levels) of government in different ways, depending on the issue at hand.
Stakeholders in environmental management issues • At a group level, stakeholders come from the private or community sectors. • Private industry stakeholders include • Industries based on the commoditisation (the use and sale) of natural resources (such as mining, wood chipping, farming and agriculture) • Property and tourism developers • Local businesses. • Community sector stakeholders include: • Non-government organisations (such as The Wilderness Society or The Red Cross) • Community centres • Educational institutions (such as schools and universities) • Churches
Stakeholders in environmental management issues • At the individual level every member of society could essentially be considered a stakeholder. • This is because environmental issues impact upon each and every one of us in some way, shape or form.
Assessing the decision making process - Environmental planning and decision making • Planning is the process of organising our use of the environment. It helps to ensure: • Environmental quality is retained while development needs are met. • Public and private use of the environment is balanced. • Rapid population growth of cities in most countries of the world since WW2 intensified the need for environmental planning. • Globalisation lead to economies being modeled on the capitalist system of economic growth which affected the way humans influence the physical and built environments.
Environmental planning and decision making • Research needs to be undertaken and used in policy decision making for planning to be effective. Research should be: • Comprehensive (cover a range of issues) and • Objective not favour the interests of one stakeholder over another.
The role of Environmental Impact Assessments (EIAs) in decision making • Environmental impact assessments • Predict the impacts a proposed action (for example, the development of a tourist resort) is likely to have on the environment to which it is being applied. • Assess the significance of proposed changes to the environment and provide a platform for discussion between different stakeholders.
Integrated environmental management • Environmental changes can affect people in positive and negative ways hence careful consideration of the viewpoints of all stakeholders is extremely important. • An integrated approach involves governments, private and community groups and individuals integrating their efforts to better utilise, manage and protect the environment.
Integrated environmental management at a government level • In July 2000 the Environmental Protection and Biodiversity Conservation Act 1999 (Cth) was passed. • The EPBC Act : • Represented a move towards greater coordination of Federal, State and Territory efforts to address issues of environmental concern in Australia. • Outlines the federal government would take the key leadership role and the authority of the States and Territories has still been upheld. • Requires an EIA to be completed before any action that may have a significant impact on the physical or built environment can be approved by the federal government.
Responsibility for Australian coastline • The Local, State and Territory Governments are responsible for coastline within three nautical miles (NM) of the shore. • The Federal government is responsible for management of waters for 200 nm beyond this. This division of powers can complicate matters because the environmental impacts of activities undertaken in coastal zones do not follow this jurisdictional division.