7.3 Geographical Processes shaping the Coastal Environment

1. The three key geographical processes that shape the coastal environment are:

·         Erosion

·         Transportation

·         Deposition

2. Wave refraction is when water bends and is caused due to headlands and the contours of the ocean floor.

3. Waves are refracted and energy is concentrated around headlands and more dispersed along beaches located in bays.

4. The most common erosional features found on coasts are around headlands.

5. The three wave action processes that shape headlands are:

·         Hydraulic Action: When water is compressed into cracks due to waves which cause erosion and create blowholes

·         Corrasion: When wave action moves rock and other material across the rock shelf and wears away the rock

·         Corrosion: When waves break they rocks. When it dries, the salt in the sea water crystallises and acts on the minerals in the rock to erode material

6. The Erosion-Accretion Cycle:

During severe storms beaches can lose large quantities of sand through erosion by waves. This sand will often be deposited offshore, forming a sand bar off the beach where it helps to limit the impact of the erosive waves on the coast. The sand that is removed will be eventually returned naturally by smaller waves restoring the beach.

7. The three forces that shape depositional landforms of beaches are:

·         Wind

·         Waves

·         Prevailing Ocean Currents

8. The most common depositional landforms found along the coastline are beaches.

9. Coastal dunes are formed by the action of the wind. When sand is deposited on the beach it is then subject to wind transportation. The wind blows the sand landward and is captured by low lying vegetation. The foredune may be eroded away or continue to grow. If it is eroded, the plants can grow back very quickly and the dunes can form again. 

The role of vegetation in the coastal dunes cycle plays a highly important role as they are the foundation of sand dunes.

10. When waves travel at an angle, longshoredrift occurs. Once waves crack, they start to loose their energy. As the swash travels up the beach it slows until gravity causes it to go back. The water will then be hit by the next wave and the sand will be transported up the coast.

11. Blowholes: As waves crash into the headland, water can be forced into cracks and crevasses causing erosion and thus creating blowholes.

Sea stacks: Sea stacks a made when sea  gradually erodes soft limestone cliffs.

Tombolos: Due to shallow water, water refracts and bends to cause erosion. This erosion stays at a constant force causing areas of land to stick out.

Offshore Sand Bar’s: When storms occur near the coast, loads of sand is taken out to sea causing large masses of sand called sand bars.

12. Fore dunes play an important part in protecting coastal areas as they provide a buffer zone for the fragile dune vegetation located on the hind dunes. When eroded, plants return and dunes are created again.

13. a.) The Twelve Apostles are located on the Great Road in Victoria

b.) They are a popular tourist location as they are very rare, beautiful and are made up of rock from 20 million years ago.

c.) The Twelve Apostles were made due to wave erosion on the coastal headlands

d.) The ‘London Bridge’ was a natural bridge that linked the mainland to offshore rock which collapsed in January 1990.

e.) No, I do not think that the collapse of the landforms could have been prevented as the erosion of waves and the transportation of weathered material is an unstoppable cycle.
14. Good Afternoon, My name is William Gulson and this is the Port Campbell National Park. As you can see, the Twelve Apostles over there stick out independently and are an amazing site known world wide. These beautiful creations are known as seastacks that are made of rock formed up to 20 million years old. The plateau behind the beach was actually joined to these rocks millions of years ago and were slowly eroded by the sea waves as refraction compressed energy into certain spots. Things like sand and rock material continuously rubbed the limestone causing these 12 rocks to stand out. In 1990, the most famous feature called London Bridge, which was a natural arch linking the mainland to offshore sea sadly collapsed. Eventually the rest of these seastacks will eventually fall apart as erosion will continue to attack these monuments.
15. Residents of a residential property were stunned earlier this week when a proposal from the local council stated that they would like to buy back the area. Local residents who own the property say the council is depriving them of their spectacular views, relaxed lifestyle and valuable property. Some of the residents believe that this is a just decision as it is believed that a neighboring fore dune is subject to major erosion. Although, there are still many shocked and appalled by the decision and there have been many letters of complaint sent to the council. Those of the property displeased with the offer have formed a group and have been discussing these offers. One woman stated, "Why should we have to move for this bloody council, I paid could money for my house and am not throwing it away". Although, an elderly man and his 70 year old wife stated, "Yes, it has been a growing concern that the wave erosion would soon get to us." In my opinion, I believe that the local council can't do such things to people that own the apartments. You cannot just put them on the street!