Asthe Gold Coat is exposed by having an extensive waterfront, rising sea levelscould wipe out the Gold Coast beaches. When the planet gets warmer, it willresult in the seawater expanding. This is called thermal expansion.
The glaciers,ice sheets or caps would also melt, and the water levels would rise, whichwould in turn flood the beaches. In some cases, the beaches would naturally migrateinland in response. More often than not, the beaches are trapped between therising sea levels and structures like roads and buildings, which would notallow them to travel anywhere. If a beach is caught between the rising sealevels and the coastal development, it would not be able to retreat inland-this, in turn, would lead to the beaches becoming narrower. Beaches generallyhave a much shallow slope.
Hence, even a small amount of sea level rise wouldovertake a significant portion of it and impact the beaches. Ifthis continues to happen, the loss of beach space would decrease therecreational area for the people living there. Sea level rise would also resultin loss of ecosystems, for example loss of habitat, and salinization of soilsmay change the distribution of plants and animals. Thisis not only a problem for the habitat, but also sea level rises would cost ahuge sum of money worth of damages and infrastructure. Many of Australia’s roads,rail, port facilities and airports are on the coastal area near the beach. Ifthere is a 1.1 meter sea level rise, that would cost more than $200 billionworth of infrastructure that is at risk.
(Fitzsimmons, 2014) Sealevels are rising internationally, specifically around the Australiancoastline- which would continue to higher up through this century. With globalincreases that are consistent, sea levels have been increased in Australia atan average rate of 2.1 mm/year over the past half century. The sea level riseprojections in Australia show that the progression of sea level rises duringthe 21st century will be even better compared to the prior fourdecades for all scenarios.
Figure 1 below shows that the projected amount ofregional sea-level rise is most significant for RCP8.5 and smallest for RCP2.6-which is the lowest concentration scenario. Sea-level change aroundAustralia by 2090 (2081-2100) compared to 1986-2005 for the four concentrationscenarios (RCPs). Source: © CSIRO and Bureauof Meteorology 2015 (Figure 1). The likelyestimate of a sea level rise in Australia by the year 2090 is 42 to 82cm higherthan the levels predicted in 1986 to 2005.
This level could increase, if alimit is reached in the global system where the land based ice sheets- forexample the Greenland ice sheet to inevitable melting. It has a very lowprobability, but it could happen, therefore it should not be ignored. If it didhappen, the consequences would be disastrous. The total melting of theGreenland ice sheet would mean that it would add approximately 6 m to globalsea levels. This would mean the global mean sea levels would rise considerably.The figure 2 below shows the projected sea level rise for major Australian coastalcities.
The coastal capital cities such as Brisbane, Darwin, Perth, Adelaideand Sydney show a mean increase of 60 to 66 cm by the year 2090 for the highconcentration scenario and 45 to 47 cm for medium concentration scenario. Figure 2: Sealevel predictions for 2030 under the intermediate concentration scenario, 2090under the intermediate To manage andmitigate the sea level rise, Australia, or more specifically the New SouthWales and Queensland Governments, created the Tweed River Sand BypassingProject. The cost is shared between the New South Wales and Queensland StateGovernments, and the Council of the city of Gold Coast. This sand collectionsystem jetty is a permanent system and it also has been designed for adeptoperation, low operating costs and also low maintenance requirements. Thisproject hinders coastal sand moving towards the entrance of the tweed river in southernQueensland Australia, and to move it up the coast. This creates and upholds aclear steering channel at the gate to the Tweed River and to also have a neverending supply of sand to the placement areas which is southern gold coastbeaches, at an amount unchanging with natural drift rates. The TweedRiver Sand Bypassing system consists of a sand collection port, that has anoverall length of about 450 meters that is constructed perpendicular to theLetitia Spit beach.
This system has been designed in a way that it is able tooperate with up to four jet pumps working simultaneously. The sand slurry isthen produced and is transported through a flume to a slurry pit that islocated on shore. It is then pumped through a 400 mm steel pipeline that islocated under the Tweed River, to one of the two fixed and two temporaryoutlets in the Northern and Southern Queensland beaches. Figure 2 below showsthe pipe network in a more clearer perspective. Figure 2:Pipeline Network (Source: WRL Coastal Imaging, 2014) What thisdoes is that it facilitates the retrieval of sand beneath the jetty andmechanical bypassing of this sand to any one of the discharge outlets located. Thiscan be seen from the figure above, which are Point Danger (Snapper Rocks East),Snapper Rocks (Snapper Rocks West), Duranbah or Kirra Point. It also providesadditional dredging from the tweed river gates and the nearshore areas that areadjacent to South Head beach and placement in the near shore places between theKirra Point and Point Danger to help in maintaining the navigation channel andto also supply additional supply of sand if it is required.
Overall this wouldgreatly help to minimise the impacts of the rising sea levels.