Geography Field Work Investigation Task.
By Rayden Dean
Introduction:
The action that is specifically extrusive along the Narrabeen-Collaroy coastline (NSW, Australia) and The Holderness Coast (Yorkshire, United Kingdom) is that of erosion and other coastal processes, presenting various connotations as well as an affluence of recent challenges that surface its inhabitants in addition to the coastal systems in ordinary. While there are many measures that are put in place to combat and aid rapid changes, in the form of various management strategies, to assess their effectiveness would be to conclude the degree of the changes and understand how the strategy will respond to the change.
Collaroy/Narrabeen – Cause and Effect of Coastal Process.
The Collaroy and Narrabeen Beaches are located on the Northern Beaches of Sydney. The North Narrabeen beach is located on latitude. 33.7095° S and longitude 151.3034° E. The coastal process that has happened to Collaroy and Narrabeen Beach is longshore drift. Longshore drift is the movement of material along a sea coastline towards an angle towards the shore. On Collaroy beach is creating high energy impact waves, when there’s a storm creates high energy waves that smash on the sea wall which absorbs the energy and pushes it with scouring. Prevailing winds are winds which push broadly from a single direction over a distinct point beach. A spit is a deposition landform that is found off coasts or lake shores. It often is developed where re-entrance is developed. The scouring (backwash) takes sand from the impact of the waves and migrates it down the coast line towards Narrabeen Beach where sand is deposited helping natural sand dunes which helps prevent Erosion. Erosion is the ability of eroding by wind and water. Within the last few years there has been no sudden change effect these beaches, however in last century there has been bad. The unsuitable planning and shoreline subdivision that took place more than 100 years ago left major erosion. This occurred 1920, seven sea shacks had fallen into pieces in 1944 and 1945. Collaroy/Narrabeen has short-term effects that impact residents, which includes the after effects of a storm when the sand dunes are repaired naturally. This also includes short term erosion which is caused by storms which changes the position of the shoreline. Long term effects however for example long-term erosion is erosion that has permanent consequences towards the shoreline positioning. Collaroy remains a problem area with most of the affected properties fronted by makeshift seawalls. Overall, the local council has started slowly purchasing some if the properties in hopes of the state government allowing a massive beach nourishment at some moment within the near future. (PROFESSOR ANDREW SHORT, COASTAL WATCH, 2008)
– Map showing the extent of the Narrabeen-Collaroy shoreline. From Google Maps.
– From Sydney Morning Herald: Manipulated image showing what the Collaroy/Narrabeen Coast might look like in 2050. This image depicts the urgency of the situation concerning the need for a permanent solution in moving property off the foredune.
Collaroy/Narrabeen – Management Strategies and their effectiveness.
Collaroy and Narrabeen beaches have been affected by coastal process for a century. Various Management Strategies should be set in place.
Management Strategy 1:
To begin with, the first management strategy that the governmental could do that would bring beneficial results would be changing the seawall in Collaroy. If this is replaced with boulders, the initial impact from the heavy waves from the storms would be drastically decreased due to the water flowing through the rocks instead of the energy refracting upstream. But they would only propose greater problems and offer protection for a very small amount of time.
Management Strategy 2:
Another management strategy would be increasing the size of the sand dunes at the beach. This could be accomplished with non-governmental organisations. Sand dunes are the natural protector of erosion, it would make sense to boost these sand dunes to compensate for long term as well as short term erosion.
Management Strategy 3
Subsequently another management strategy could be Voluntary repurchase. This involves the resident’s homes being purchased back from the local council at a reasonable market value and destroying them making it a very sustainable and effective way of managing coastal process. Overall, the management strategies provided are very effective, but the NSW government have lacked in effort to provide the Northern Beaches with care and protection against coastal process.
– A heavy change in cross-section measured at Narrabeen-Collaroy Beach as part of the long-term coastal monitoring program. An incredible 50m shift in beach is observed over a 3-day period.
– Image showing the extent of the changing of the coastline. (A) and (B) shows the coast prior to the oscillation in the sea moving landward. (C) and (D) show the variable movement in tide showing extent of erosion and how it will only continue indefinitely. From Research Gate showing pre and post storms.
Yorkshire/Holderness Coast – Causes and Effects of Coastal Processes
The Holderness Coast is located on the east coast of England and enlarges 61km from Flamborough in the north to Spurn Point spit which stands in the south. The Holderness Coastline is one of Europe’s quickest eroding coastlines. This is shown through the 2 metres of erosion annually, leading to the consumption of roughly 2 million tons worth of materials. Within stormy conditions, waves from the North, creates longshore drift which pushes the gigantic waves towards the coastline chipping roughly 7 to 10m of the coastline. It is speculated that there has been close to 5 km of land lost due to erosion since the Roman era, including at least 23 towns and villages. The short-term consequence for residents is the decrease in property value, this is a factor due to the frequent erosion chipping away the coast, resulting in the demand being very little for houses on the coastline. For the ecosystem, there are many natural habitats for animals getting destroyed, along with plants that develop on particular coastal types. However, the long-term impacts can result in serious destruction to residents. Since erosion is the biggest problem on the Holderness Coast, the land is slowly getting destroyed especially homes on the beachfront. They can often be ripped to shreds causing the whole house to be destroyed. Long term consequences for the ecosystem could include Plant loss as erosion removes the topsoil from the ground, this often removes the seed bank that inhabits the soils. This therefore can introduce toxins from pesticide and fertilizer applications into waterways causing contamination to the waterways. The rate of erosion on the Holderness Coast is astonishing. Each year an average 2 metres of the coast is taken away. This shows that erosion is one of the biggest issues on the Holderness Coast. In storm seasons, there can be 7m to 10 metres of rock and soil chipped away taken residents home and polluting the water way, showing the fast rate of erosion along the coast.
– A map showing the Holderness Coastline and the previous effects of erosion causing towns to be removed, dating all the way back to the Roman Era.
– A diagram of cliff erosion and wave cut platforms in detail. – Kenneth A. Bevis 2013 – Geography
Yorkshire/Holderness Coast – Management Strategies and their effectiveness
The Holderness Coast in Yorkshire is one of the fastest eroding coasts on earth. The coast has been affected from erosion since the Roman era, management strategies haven’t been set in place to prevent the astonishing average 2 metres of coast being taken every year.
Management Strategy 1:
The first management strategy that should be set in place would be to advance the existing defence line against erosion. This would roughly cost 100 million pounds. A defence line against erosion could be accropodes blocks, they are very effective as their primary focus is to resist waves. They are made out of unreinforced concrete which is designed resist the action of the high energy waves on breakwaters along with coastal structures, they would have to be implemented by the Government.
Management Strategy 2:
Another defence line would be the SMP (Shoreline Management Plan) the aim of this is to provide support for sustainable coastal defence polices within a sediment cell and to set objectives for the future management of the coastline. SMP is funded by the local councils making it fairly effective, it would be a lot more effective if the government funds the management plan. A distinct management plan would be a Groyne. A groyne is a low wall into the sea from the beach to prevent coastal processes like erosion.
Management Strategy 3:
A groyne would be a low cost but effective way that the government could fund and to combat coastal processes such as erosion and longshore drift. As a groyne is rigid and interrupts the water flow limiting the movement of sediment and is most effective made in concrete. In the ocean, groynes create beaches or prevent them being washed away by longshore drift. Overall, the Holderness Coast is one of the fastest eroding coasts worldwide, while Narrabeen and Collaroy have had a minor effect on erosion the management strategy’s share a very similar perspective on coastal process. When the government has provided weak management strategies at home in Australia, the English government have responded with effective plan in aiding coastal process such as erosion on the Holderness Coast.
As an evaluation for both of these strategies, it may be concluded that the Holderness Coast seeks for a combative long reaching solution while Collaroy/Narrabeen seek in a still attitude for short term solutions and fail to be aggressive in dismantling infrastructure that is sure to cause problems in the future.
Proposal:
Overall, after appraising the ecological sustainability of both Narrabeen/Collaroy and the Holderness Coast, a conclusion could be made in terms of what individuals, local councils and the government can commit to confirm these requirements. The main outline for management around Narrabeen/Collaroy should be achieved of the coastline needed now to ensure that, as coastal process proceeds, there will be no other destruction can come to residents. This can illustrate in the form of the council slowly, but eventually buying back the property to nourish the ecological sustainability of the foredune for the following erosion to proceed. All these actions provide long-term solutions to broad erosion of the world’s coastlines.
Bibliography:
References:
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