Coastal Processes

​Karakia:

Tuia ki runga

Tuia ki raro

Tuia ki waho

Tuia ki roto

Tuia te here tangata

Tuturu o whiti, whakamaua

Kia Tina… Tina!

Haumi e… Hui e….

Taiki e!​

On the following slide, choose ONE geographic concept (write it down). Justify how you think your chosen concept could be relevant in a Coastal Processes topic. ​

Erosion, Transportation, Deposition​

The loss or displacement of land, or the long-term removal of sediment and roacks along a coastline due to wave action. ​

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​Coastal Erosion

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The movement of material in the sea and along the coastline by waves.​

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​Coastal Transportation

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​When the sea loses energy, it drops the sand, rock particles and pebbles it has been carrying.

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​Types:

There are many different types of erosion that can occur within coastal environments. These are:

• ​Abraision

• Attrition

• Corrosion

• Hydraulic Action​

When rocks and stones hit against each other, wearing them down to create smooth pebbles. ​

​Attrition

When rocks and other materials are picked up by waves and thrown against the coastline causing more material to be broken off. ​

​Abraision:

WHen air becomes trapped with cracks in rocks and causes rocks to break. This occurs with large waves with high energy. ​

​Hydraulic Action:

​When the salty sea water dissolves parts of rocks.

​Corrosion:

​Erosional Landforms

The most active area of erosion is that area between high tide and low tide marks on the coast. This is called the foreshore.

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This is the areas which cliffs are highly exposed to high energy waves - resulting in different landforms. ​

Weaknesses in the rock will be attacked by wave action. These are exploited and caves can be formed. ​

​Caves:

Where cliffs are attakced by waves they will create a wave cut notch at the base of the cliff. ​

​Wave - Cut Notch:

When continued erosion the roof of the arch may collapse. This will leave a stack.​

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​Stack:

When caves form in headlands, the cave can go through the entire headland, creating an arch. ​

​Arch:

On the following page, draw a timeline of your own representation of the formation of coastal landforms.

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NOTE: You can find pictures and add these in as well. ​

​Move around your room and see if you can identify 5 objects that start with the letter B!

Write your answers on the following page!​

Movement of material from one place to another. This is accomplished two ways:

• ​Wind

• Water​

​Transportation:

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​Longshore Drift:

Controlled by the direction of the wind.

Waves break up the beach (swash) at an angle, and move material in theat direction. Tehy then backwash straight backwards from the beach - creating a zigzag motion.​

​Wave Action:

This is limited to fine, dry sediments that can be blown by wind. Generally this is sand moved by previaling winds.

​Wind Action:

​Beaches are created in sheltered areas of the coast (often in bays) where the waves are not so strong or the effects of longshore drift are restricted.

​​Beaches:

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​Formed where the coastline changes direction or where the flow of material is disturbed at a river mouth.

These are narrow landforms that are attached to the coast at one end.​

​​Spits

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​Formed when an island is connected to the mainland by depositional material.

​​Tombolo

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​Shallow, shifting sandbanks at the entrance to river sna coastal estuaries. These are formed offshore where there are conflicitng currents - causing the carrying capacity to be reduced.

​​Bars:

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​Depositional features as a result of longshore drift. Are formed when a spit develops right across a bay which traps a lagoon behind it.

​​Baymouth Bars:

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​Created by wind (aeolian) actions. Material is moved up the beach and depositied when the wind loses its carrying capacity. These are stabilised by vegetation.

​​Sand Dunes:

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​Answer the following multiple choice questions about coastal depositional features!

Using the information you have learnt, have a go at writing a detailed paragraph surrounding how coastal systems work.

NOTE: You need to discuss coastal erosion, transportation, and deposition.​

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