Half Yearly Notes

Management of the Coast

  • Sustainable management must occur
  • Environmental Impact Statement (EIS) must be prepared to show the likely impacts on the physical environment as well as social/economical impacts, before a decision is made
  • The results are distributed and interest groups ie. all government levels, business, recreation and sporting associations invited to respond

Decision Making Processes and Decisions

  • To ensure social justice and equity, all perspectives need to be considered before development applications (DA) can be approved
  • Conflicting views of the stakeholders need to be resolved and decisions must be made by informed and aware citizens based on information sourced from governments, scientists, and responsible media reports.
  • Different groups including government officials, university professors, scientists, environmental groups and home property owners along the seaside need to be consulted about structural intervention

Consequences of the Processes

  • Stakeholders can attempt to influence the decisions of governments by:

-Protest- Demonstrations- Petition

-Rally - Sydney Coastal Councils- Blockade

-Lobby politicians- Writing to the local MP

-Forming action groups

-Dredging machines can stop buildup of sand in harbours by pumping sand off the harbour and down the coasts

-Dams become controversial as they are needed for hydraulic power, flood control and other purposes, but they disrupt the balance of deposition by trapping sand normally washed to the beaches

-Seawalls become controversial as they reflect energy off straight off and worsens erosion at the base, also cut sand supply to the beaches. Nature’s energy absorbing design is installed to build seawalls in an irregular shape

-Factors causing changes in sea levels include:

  • High tides caused by gravitational force from moon and sun
  • Melting of ice sheets and glaciers from the last Ice Age tens of thousands of years ago and from greenhouse effects

-Botany Bay was a shallow depression that flooded when the sea level rose in the last Ice Age

-It was changed by European settlement which cleared the land for agriculture, heavily urbanised and industrialised the area, and put the natural processes and ecosystems under threat

-Management issues include:

  • 140 mil L of sewage flowing in each year from Georges and Cooks rivers
  • commercial fishing banned in CooksRiver and a large proportion of GeorgesRiver because of a health risk of eating the fish
  • oyster farms killed by pollution
  • development of SydneyAirport destroyed habitats and encouraged urbanisation and industrialisation
  • erosion of beaches within the bay caused by removal of sand from sea bed to build airport and port extensions
  • development of Port Botany destroyed habitats and increased water pollution
  • more than 1300 ships annually discharge toxic ballast water and toxic paint at bottom of ships is dissolved in water
  • Kurnell tombolo at risk from severe storms because of removal of sand in sand mining
  • More than 50% seagrasses which are nursery grounds for many species of fish and shellfish, have been destroyed in the last 30 years

-Solutions carried out include sand nourishment, reduction or abolishment of sand mining, banning of fish farming, and reduction of urbanisation and further intrusion into nature

-The process of decision-making is shared between government of all levels, industry groups and communities, and the responsibilities are spread between different authorities at state level

Solution / Description / Advantages / Disadvantages
Beach nourishment / The artificial placement of sand on a beach on which the sand is then spread along the beach by natural process / Sand best matches the natural beach material
Low environmental impact at beach / Sand must come from another beach where environmental impacts may occur;
Must be carried out continuously and needs large funds
Groynes / A structure designed to trap sand from being moved by longshore drift, and can be built from timber, concrete, steel pilings and rock / Traps sand and maintains beach / Groynes do not stop sand movement directly offshore
Visual eyesore
Sea wall / Structures placed parallel to the shoreline to separate the land area from the water / Prevents further erosion of dune area and protects buildings / - Erosion would be worse at base from reflected wave energy from straight wall;
- Visual eyesore;
- Needs sand nourishment program as well;
- High initial cost;
- Ongoing maintenance and cost
Offshore breakwater / A structure parallel to shore, placed in a water depth of about 10m / Waves break in the deeper water, reducing energy on the shore / Destroys surfing amenity of coast
Requires large boulders in large quantities
Costs would be extremely high
Purchase property / Buy and remove the buildings threatened by erosion / Allows easier management of the dune area
Allows natural beach processes continuing
Increases public access to the beach / Loss of revenue to the local council
Possible social problems with residents who must move
Exposes backdune area
Extremely high cost
Doesn’t solve sand loss
  • Seagrasses are meadows found in shallow waters of protected estuaries and bays, and provide nursery for many marine organisms eg. fish and shellfish.
  • Removal and destruction of seagrasses impact on commercial and recreational fisheries, and loss of stabilisation of sediments on sea bed would result, thus increasing erosion and change the wave pattern
  • Management occurred include replanting seagrasses in temperate waters, but none were successful as seagrasses grow and spread very slowly
  • Marshes and wetlands provide nurseries for and are dependent on by marine life and therefore food and shelter for migratory birds, but they are being destroyed by pollution, human intrusion and clearing of land for agriculture