Essay about Beach dune erosion

Wind and waves affect Glenelg as they set up a northward drift of sand along the coast and this type of sand movement is known as littoral drift. During coastal storms, huge quantities of sand are eroded and this does damage to near shore, beach and sand dune areas. Glenelg is not considered to be a stable as beach as many others are. Seagrass loss and seabed instability that affect Glenelg is that a third of seagrass meadows along the coasts of Glenelg has died since 1950 and poor water quality resulting from the stormwater runoff and effluent disposal has most likely been the initial cause. When there are gaps in the seagrass meadows the sand below the meadow edge can be eroded by the waves and this will in turn increase the rate of seagrass loss and make it difficult for plants to recolonise the seafloor, even though the water quality has been improved. Sea levels affect Glenelg as parts of Glenelg are being subsided as a result of climate change and a relative sea level rise of one to two millimetres per year has been recorded for Glenelg. “As a result of the loss of sand from the seabed, the level of the seabed has steadily become up to one metre deeper and the wave energy reaching our beaches has increased.” (Adelaide’s Living Beaches Strategies,

Natural disasters are considered harmful in terms of coastal management and can often cause years of work to be wiped out. It can take large amounts of sand from the beach and remove plant life. Collaroy Beach has been a victim of such natural disasters. A large storm back in 1945 caused Collaroy Beach to empty out a large percentage of its sand and damaged many structures. Collaroy Beach’s local council, Warringah Council, has taken action to prevent storm damage in the future. A revetment wall has been established on the sand dunes so waves do not cause as much damage to the dunes behind. Warringah has also purchased properties that were residential and cleared them, so that a storm will not damage as many structures.

It has become common for sand dunes to be bulldozed to improve the views to the sea. However this destroys the natural protection of the coast. Human activities such as water transport also can cause problems for coastal areas. The dredging of navigation channels and the discharging of the material in deep water to enable larger ships to travel though water channels removes sediment from the coastal system leaving the area susceptible to erosion and will also interfere with longshore drift which will prevent the coastal beach landforms from being maintained such as the development of a spit. It is likely that a spit will be eroded and start to regress in conditions such as these.

Newhaven is well known for having a harbour arm built in 1890 and is 700m wide. The harbour stops any sediment from moving further and protects river Estuary from any longshore drift damage. The harbour also allows boats to preserve their acess to the river Ouse. Longshore drift occurs when waves approach the coastline at an angle of 45°. The sediment is then carried up the beach (Swash) at the same angle. The wave then moves back down (Backwash) at 90°. This results in a zigzag motion along the beach which transports and deposits sediment along the coastline. The formation of the cliff depends on erosion or weathering, the three main types of marine erosion include abrasion, attrition and hydraulic action. The two significant types of weathering in coastal areas are corrosion and wetting/drying. As a result of longshore drift, the sediments and shingle is transported from the sea and tends to be depostited on the oppersite side of the harbour arm. The beach is used mainly by locals of pleasure and lesuire. predict that the cliff will be

sand being deposited upon it. The only reason why beaches shrink is due to erosion and this

At Nudgee Beach, erosion was found to have occurred on the edges of the mangrove forest and along the mudflat shorelines. Erosion is typically influenced by natural factors and occurs when pieces of weathered rock or soil are moved – typically by wind and water – from one place to another. Shorelines with lots of sediment and sand are more inclined to be effected by erosional progression. Erosion may also be provoked and accelerated by human interference. For example, if the decision to clear trees and plants from an area is made, erosion is likely to occur as the root systems of plants work to hold the soil in place. If these root systems are removed and erosion does occur, environmental conditions – such as; landslides and flooding – are more likely to take place. Erosion may also cause other plants to tip over, have their underground roots exposed and damaged and contribute to the pollution of local waters; as a result of mud and soil runoff [26]. Erosion at Nudgee Beach was likely to have been influenced by natural factors; however, the development and extension of the Kedron Brook golfing course may contribute to the acceleration of erosional processes and further damage the mangrove

Brighton, Glenelg, The West Beach Boat Ramp, Semaphore and Largs North Beach have all been influenced by hard engineering techniques. As an example, Glenelg was one of the few beaches that had some form of a breakwater along the coast. Breakwaters are notorious for having immediate impacts on the beach, but are ultimately useful in protecting the land that meets the beach. The real question is; “Do the benefits, outweigh the negatives?”. Breakwaters are

A healthy dune system contains a primary and secondary dune defined by the start of vegetation as you progress from the swash and berm. The vegetation helps stabilise the landform helping to protect it from erosion, it also helps the soil in the secondary dune to become more stable and erosion resistant. The decaying plant material creates humus which makes the soil more nutrient allowing greater plant diversity.

walls. Rip rap walls are when larged rocks are piled in a certain angle to catch drifting sand and protect the beaches from harsher waves and to protect buildings from high

Barrier beaches are not static, they are constantly being changed (Coastal Change ) by the forces that formed them; waves and wind. One change effecting barrier beaches is they are moving closer to the main coast. This movement is caused by the rise in sea level. As the sea level rises waves crash higher and higher upon the beach, as they do this the dunes are pushed back. There are also seasonal changes in the barrier beaches. During stormy seasons sand is removed from the beach and deposited off shore on the longshore bar. During calm season waves redeposit sand upon the beach and the beach grows.

Sand dunes are mounds of windblown sand, which vary greatly in size, from less than one meter to tens of meters high. The size depends upon the supply of sand. Many of the more recognizable dune forms are ridges or complexes of mounds or crescents. The shape of individual dunes is equally variable. Shape relates to the direction and strength of the wind forming it, as well as to the amount of sand available. The impressive sand dunes along the eastern shore of Lake Michigan were created by the prevailing westerly winds blowing the sand deposited along the beaches into the dune

These sand dunes are important to the coastline and should be protected from these natural threats. The dunes are important because it is used as a buffer against wave damages caused by storms, cyclones, king tides, etc. which protects the land behind from salt water intrusions. The dunes also act as a sand storage area to replenish and maintain the beach at times of erosion. “Sand suns also provide a foundation for ecosystems made up of a wide variety of coastal life.” (http://curiosity.discovery.com/question/why-dunes-coastal-areas). Due to the sand dunes being swept away by the cyclones and king tides all the protection that the dunes are providing to the inland is slowly decreasing because of the erosion that the cyclones and king tides cause. The erosion effects the foreshore most out of all the parts of the sand dunes. The foreshore is most affected because it is where the waves are most frequently hitting that part of the sand dunes which means that erosion will occur faster there. Due to the foreshore wearing away, sand from the foredune and interdune will replace the sand that has been washed away which means that the establishments that are on the interdune will begin to sink into the

If any architecture is structured poorly, erosion can easily contribute with destroying it. Architects have to design a building in a way that will be sturdy to complications like erosion.

Some amount of natural erosion is necessary to provide the sediment for beaches in estuaries and coastal bays. However, excessive erosion has occurred in the past due to development. Industrial and private development along the world’s coastlines has increased dramatically since the 1970s (Nepf). Developers and builders completed much of this construction without taking into account the effects of coastal erosion. New buildings were often placed too close to the existing shoreline so that

The natural processes that are a cause for the destruction of the beach are mainly erosion by the waves and the wind. While we were there we did not witness any destructive erosion, as this happens when a cyclone hits and causes the waves to hit the foreshore at a faster rate.