Working towards a Bachelor of Arts, Simran writes articles on modern history, art theory, religion, mythology, and analyses of texts.
The major geographical processes that form and transform coastal environments are erosion, transportation, and deposition. Coastal erosion wears and breaks off materials along the coastline. Transportation is when sediment is transported by currents, rivers, and constructive waves to a destination. Deposition describes how sediment builds up coastal landforms due to transportation. The processes outlined can present problems to unprotected coastal areas, such as the Collaroy beach and the Narrabeen lagoon. Therefore, coastal landforms are continuously shaped by geographical processes that presents environmental issues to Narrabeen-Collaroy.
The Beach Profile
Erosion transforms coastal landforms but causes management issues to Collaroy beach. Erosion typically occurs when the wave energy is high, which is influenced by strong winds and low-pressure weather. The common processes of erosion include: hydraulic action and corrasion. Hydraulic action is the shear wave hitting the coastline and its backwash pulling materials back into the ocean. Corrasion is when weaker layers of materials disintegrate or dissolve into the ocean. This presents a vital problem at Collaroy beach. For instance, a current issue of Narrabeen headlands is how the hydraulic action of waves causes weaker layers of stone to be dissolved by the ocean. This is an issue because once the headlands are eroded, the beach will take the full force of the wave and its sand will be completely eroded. Henceforth, erosion transforms coastal landforms through hydraulic action and corrasion, yet raises issues at Collaroy beach.
Deposition builds coastal landforms and reinforces coastal management at Collaroy beach. It is associated with high-pressure weather where there is a low wave energy. For example, during sunny conditions in Collaroy beach, constructive waves transport eroded sediments from cliffs and headlands to build up the beach. As a result, dried out sediments are carried by the wind towards the land. This forms a foredune and a backdude. Vegetation begins to grow as soil quality and freshwater improves away from the beach. The vegetation's roots bind and stabilise the sands, reducing the effects of erosion. This is used to maintain Collaroy beach through dune management. To illustrate this, plants, such as the coastal wattle and coastal banksia are planted to maintain Collaroy beach. Therefore, coastal landforms are built and maintained by deposition, as seen through the dune management at Collaroy beach.
Weathering and Erosion: Crash Course Kids #10.2
Transportation provides materials for coastal landforms, however, it causes environmental problems in Narrabeen lagoon. A common process of transportation is longshore drift. Longshore drift is when the wind causes waves to approach the beach in a direction. The wave’s swash moves materials upwards and its backwash pulls the materials down. How the material gets carried depends on its size. Particle beach material would either be carried by waves or dissolved by waves. Nevertheless, it introduces an environmental issue in Narrabeen lagoon. To exemplify this, the sand from Collaroy is being transported by longshore drift to Narrabeen lagoon, which is an unprotected region. This presents an environmental issue for Narrabeen as the sand fills up the lagoon making it unsuitable for the fauna and flora inhabitants. Thus, transportation provides materials for coastal landforms through longshore drift, which introduces an environmental issue at Narrabeen lagoon.
Coastal environments are formed and transformed significantly by erosion, transportation, and deposition. Erosion transforms coastal landforms through hydraulic action and corrasion. This causes a major issue in Collaroy beach as materials from headlands are eroding. Transportation provides materials for coastal environments through longshore drift. It causes sand to be transported to Narrabeen lagoon, threatening fauna and flora inhabitants. Deposition builds and maintains coastal environments through the growth of dunes. Dune management is often utilised to maintain Collaroy beach. Ultimately, it is essential for environments to be managed properly, if not, then nature will work against it.