Presentation on theme: "Coastal Management Focus Area 5A3 Issues in Australian Environments."— Presentation transcript:
Coastal Management Focus Area 5A3 Issues in Australian Environments
Syllabus: Coastal Management Students learn about: the geographical processes relevant to coastal management the perceptions of different groups about coastal management individual, group and government responses to coastal management decision-making processes involved in the management of coastal management management of coastal management and the implications for sustainability, social justice and equity
What is Coastal Management? It is aimed at developing and implementing strategies to preserve and protect our coastal environment. Human activity increasingly threatens our coastal environs through e.g. foreshore development of high rise hotels, residential buildings, population growth, planting of non native species of plants etc.
Did you know? ￼ There are 721 beaches along the New South Wales coast. Their average length is 1.5 kms and they are generally bordered by rocky headlands. The longest beach in NSW is Ten Mile Beach, Shark Bay, near Evans Head (far north coast) with a length of 17.5 kilometres.
Geographical Processes Relevant to Coastal Management
What is a Geographical Process? A geographical process changes the geography of a region. For example, the destruction of the rainforest in the Amazon can change an area from rainforest to cleared cropland or grazing areas. A geographical process may also be a natural process that transforms one landform into another. An undersea volcano may eventually become an island that towers over the sea. A hotspot volcanic chain, such as the Hawaiian islands are an example.
Hydraulic Action This is when air in cracks on the cliff face becomes compressed by the power of the waves striking the cliff face. As this happens the air inside the crack is compressed, putting a lot of pressure on the surrounding rock. The air then expands explosively, forcing out pieces of rock. Over time, the cliff face crack breaks causing a larger crack or cave to form. The rock from the cliff face which was removed falls to the bottom of the sea bed and is also used for another wave action- Corrasion (Abrasion).
Corrasion (Abrasion) This is when the waves break on the cliff face pounding the cliff face slowly eroding it. Along with the cliff face being eroded by the power of the sea the sea also uses the scree ( an accumulation of loose stones or rocky debris lying on a slope or at the base of a hill or cliff ) from other wave actions. As the sea pounds the cliff faces it also uses the scree to batter and break off pieces of rock from higher up the cliff face.
Corrosion The action of salt on minerals like iron that are contained in rock and making it more susceptible to erosion. The rocking action of the sea also makes it easier for the sea to erode limestone cliff faces as the rocking action of the sea acts as the stirring motion in a chemistry experiment which helps to speed up a corrosive experiment.
Geographical Processes Affecting 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.
The Formation of 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. Natural wind energy forms waves 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. What determines the size of waves on the shoreline?
Waves Breaking on the Shoreline 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 The active part of the coast in terms of erosion and deposition of sand by wave action. The swash zone is at the shore once the waves have broken Backwash is the a backward flow or movement of water produced especially by the propelling force of the wave i.e. the combination of the force of the swash and gravity makes the water move backwards
Longshore Drift The action of swash and backwash mean the grains of sand can move in a zigzag motion along a beach.
2 Main Types Of Waves Constructive (good) Destructive (bad)
Constructive Waves o These waves build beaches. o Each wave is low. o When a wave breaks it carries material up the beach in its swash. o The beach material will then be deposited as the backwash soaks into the sand or slowly drains away. o These waves are most common in summer.
Destructive Waves These waves destroy beaches. o The waves are usually very high and very frequent. o The back wash has less time to soak into the sand. o The continual hitting of waves on the beach means there is more running water to transport the material out to sea. o These waves are most common in winter.
Features Of Coasts Caused By Erosion
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.
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.
Plants Helping The Coastline
Plants - Onshore 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.
Plants -Underwater 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.
Groups Perceptions affected by Coastal Management
Stakeholders Residents Who wish to enjoy the delights of living by the coast – views, water sports, more temperate weather etc. Developers Who see the opportunities for making big profits because of high demand for coastal access and views Environmentalists Who are concerned about over development of coastal areas and believe that it is often ugly and unnecessary as it spoils the appearance of the area and causes damage to native flora, fauna and environs Governments Local - Waringah Shire Council, Byron Shire Council etc. State - NSW, Qld, Victoria etc. Federal - the Prime Minsters office, Department of Defence, Office of the Environment etc.
Responsibility for the Australian coastline The Local, State and Territory Governments are responsible for coastline within 3 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.
Individual, Group And Government Responses To Coastal Management
Sustainability Is the most significant of coastal issues Being able to meet the needs of the present without compromising the needs of future generations
Human Impacts On Coasts – Stakeholder Perceptions Stakeholders or groups with an interest in coasts include: Housing residents Environmentalists Governments Community members Boat owners Miners Tourists 1.Housing and development 2.Ports and marinas 3.Stormwater run-off and pollution 4.Sand mining 5.Recreation and tourism
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, 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.
Storm water 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 & 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.
Ports & 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 (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.
Sustainability, Social Justice & Equity
What Are They? 1. Sustainability - achieving environmentally sustainable outcomes. 1. Social justice - ensuring the outcome achieved is socially just (or fair) for all stakeholders. 1. Equity - ensuring decision-making processes through which the outcome is achieved are equitable for all parties involved.
Stakeholder Co-Operation 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 are not integrated in 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. The entire process needs to be managed in terms of how it reflects upon Australia's level of sustainability, social justice and equity
The Role of Environmental Impact Assessments (EIAs) 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 (Sustainability aspect) Assesses the significance of proposed changes to the environment and provide a platform for discussion between different stakeholders. (Social Justice aspect)
Environmental Planning & 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.
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.
Coastal Management Strategies Coastal management involves developing strategies designed to protect and preserve the coastal environment. Construction of protective barriers and walls Beach nourishment Coastal dune preservation
Conservation Conservation refers to using the Earth’s resources in a sustainable manner. The Australian Conservation Foundation (ACF) is a non- government organisation involved in conservation issues. The ACF aims to protect, restore and sustain Australian environments by working in collaboration with stakeholders.
Preservation Preservation is concerned with keeping things in their present state or form. Preservation means Reducing human impacts on the physical environment by not touching things that remain in their natural state. Protecting unspoilt ecosystems through the creation of national parks, nature reserves and marine sanctuaries.
Management Strategies Activity Explain why the following terms are considered good strategies for managing coastal erosion and other issues. Refer to SIMB reference articles as a starting point for your explanation Sea walls / Boardwalks / Groynes Jetties / Harbours / Marinas Breakwaters / dredging river mouths or coastal estuaries Beach replenishment Sand dune preservation (including re-vegetation) Water quality monitoring
Protective Barriers & Walls
Sea walls Used to stop erosion of the coastline and protect property. They often replace the fore dune, which is an essential part of the beach erosion. The scenic appeal of the beach may be reduced by their construction.
Breakwaters Constructed at the entrances to rivers. They extend into the ocean in order to stabilise river entrances and provide safe access for boating by keeping the river entrance clear of sand build-up. They can act to dramatically alter patterns of erosion, transportation and deposition of sand along the coastline.
Groynes Constructed along beaches (almost at right angles to the shore) to catch sand and make beaches wider. They protrude into the ocean and are designed primarily to slow down the rate of longshore drift. Sand tends to accumulate on one side only, creating a different beach from its natural shape. Traditionally made out of wood or rocks and concrete but often now textile bags filled with sand are being used.
Beach Nourishment Beach nourishment involves the movement of sand by machines. Large quantities of sand are moved from a point where it accumulates to a point where it has been eroded. It is an expensive beach management technique and needs to be ongoing. Dredging river mouths along the coast is a common source of sand for beach nourishment e.g. Narrabeen Lagoon & Collaroy Beach
Coastal Dune Preservation Limiting new developments in coastal dune areas to allow dunes to play their natural role as a buffer between the beach and the land and avoids councils having to build elaborate sea walls to protect property. Constructing fences to control access of pedestrians and vehicles across sand dune areas. This helps stop erosion as trampling vegetation removes the protective covering. Revegetation to help stabilise the dunes when the natural vegetation has been removed.
Coastal Management Strategies - The Advantages & Disadvantages Brief description of management strategy AdvantagesDisadvantages Construction of protective barriers Protects property Maintains river openings Collects sand lost to long- shore drift Increases erosion Unsightly Alters patterns of transportation of sand along beach Unnatural shape given to beach Beach nourishmentReplenishes lost sand to beaches Expensive and ongoing maintenance Coastal dune preservationAllows dunes to play their natural role Stops erosion Stops destabilisation Avoids more expensive structures such as sea walls Restricts movement on beach Limits development