NATURAL DISASTERS
Natural disasters can have profound impacts on a society as a whole, while largely affecting coastal environments on both a local and national scale. Coastal Inundation refers to the flooding of coastal land by large ocean tides, high waves or severe storms, transporting sand away offshore, influencing many Sydney beaches such as Collaroy, Cronulla and Coffs Harbour. Additionally, global warming effects, including increased melting ice caps and thermal expansion - expansion of water as it heats up - results in a rise in sea level. This in turn, will result in the drowning of lower level coastal areas or the readjustment of the shoreline to new higher coastal water levels, both resulting in the loss of beach sediment from the land. Moreover, other natural disasters such as cyclones and fire, usually wipe out the contents existent on beaches, leaving land devastated and thus more vulnerable to exogenic processes.
As natural disasters are generally quite unexpected, councils are forced to respond to the erosion caused very quickly. Methods of combatting coastal erosion, such as beach replenishment and sea wall constructions, require payments to both the workers in order to complete the job, and the vital raw and physical materials, such as the steel and concrete for sea walls or several tonnes of sand to replenish eroded land. The 1974 storms and high waves had severely impacted Cronulla Beach and resulted in widespread coastal damage. Most vegetation was wiped out, a 340 metre sea wall was consequently constructed, and about 200,000 tonnes of sand was required in the process of replenishment.
Fig 2.1: This is a ground-level photograph of the sea wall that was constructed after the 1974 storms had washed away a large portion of sand from Cronulla Beach, severely eroding the shoreline. From the photography, we can see that the sea wall is comprised of blocks, called 'seabees', which are of hexagonal shape and consists of holes. The purpose of the holes is to absorb the energy from the waves rather than deflecting it back and transferring the issue of erosion to other sections of the beach.
Source <Parker, B., Lancely, K., Owens, D., & Rebecca, F. (2008). Geography for Australian Citiziens (3rd ed.). (G. Smith, Ed.) Melbourne, New South Wales, Australia: Macmillan Education Australia Pty Ltd.>
As natural disasters are generally quite unexpected, councils are forced to respond to the erosion caused very quickly. Methods of combatting coastal erosion, such as beach replenishment and sea wall constructions, require payments to both the workers in order to complete the job, and the vital raw and physical materials, such as the steel and concrete for sea walls or several tonnes of sand to replenish eroded land. The 1974 storms and high waves had severely impacted Cronulla Beach and resulted in widespread coastal damage. Most vegetation was wiped out, a 340 metre sea wall was consequently constructed, and about 200,000 tonnes of sand was required in the process of replenishment.
Fig 2.1: This is a ground-level photograph of the sea wall that was constructed after the 1974 storms had washed away a large portion of sand from Cronulla Beach, severely eroding the shoreline. From the photography, we can see that the sea wall is comprised of blocks, called 'seabees', which are of hexagonal shape and consists of holes. The purpose of the holes is to absorb the energy from the waves rather than deflecting it back and transferring the issue of erosion to other sections of the beach.
Source <Parker, B., Lancely, K., Owens, D., & Rebecca, F. (2008). Geography for Australian Citiziens (3rd ed.). (G. Smith, Ed.) Melbourne, New South Wales, Australia: Macmillan Education Australia Pty Ltd.>
Glossary
Natural Disaster - A natural and catastrophic event, such as floods, cyclones and earthquakes, which ultimately inflict large damage within an area
Coastal Inundation - Process of tidal waves flooding coastal area
Beach Replenishment - Process of placing more sand into an eroded beach area
Sea Wall - A revetment designed to protect an area from sea waves and erosion
Global Warming - Gradual increase in the Earth's atmosphere due to greenhouse gases, which are caused by the rising levels of carbon dioxide
Natural Disaster - A natural and catastrophic event, such as floods, cyclones and earthquakes, which ultimately inflict large damage within an area
Coastal Inundation - Process of tidal waves flooding coastal area
Beach Replenishment - Process of placing more sand into an eroded beach area
Sea Wall - A revetment designed to protect an area from sea waves and erosion
Global Warming - Gradual increase in the Earth's atmosphere due to greenhouse gases, which are caused by the rising levels of carbon dioxide