What is Spit Coastal Feature?
The spit coastal feature or the spit geography is largely formed by the deposition of sediments like the sand by the huge water bodies such as the oceans or seas. It is usually a sandpit, a type of deposition bar forming a part of the beach landform off the coasts or the shores of the lakes. The spit geography is developed at places where there is re-entrance of the water from the water bodies like the cove’s headlands. This is generally aided by the process of longshore drift carried by the longshore currents. The drift generally occurs when the waves meet the beach at an oblique angle and move the sediment down the beach in a zigzag pattern.
Factors Affecting the Spit Geography Definition
It is clear that spit geography is formed from the deposition of sediments by the longshore currents carrying a longshore drift. The drift that forms the main factor of the spit geography definition happened due to the waves meeting the landforms of the beach at oblique angles and then moving the sediments down from the beach to the ocean in a zigzag manner. This entire process forming the core of the spit geography definition is also complemented by the longshore currents as well which increase the transport of the sediment by the water alongside the beach. These longshore currents and the longshore drifts are both caused by the same set of waves coming from the water body.
The Spit Geography is Depicted by the Following Diagram:
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The longshore current generated by the waves spreads out and dissipates at places where the direction of the inland shore re-enters or changes its direction for example at places like headlands. Thus, as the longshore current which is already carrying enough load of sediments dissipates near the coastal features like the headlands, it is unable to carry the same load and so drops much of the sediments. This process is known as a deposition. The submerged bar of the sediment allows the longshore drift to continue to transport the sediment towards the direction of the waves breaking and form an above-water spit. Without any of the complementary processes of the longitudinal drift, the sandbar would not have been formed above the water leading to the formation of a spit geography but instead would have been run off by the water or levelled off by it.
An Image of the Spit in Contrast With Other Coastal Landforms is Shown in the Following:
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Formation of a Spit Geography
Now, it is very well established that the reason for the formation of spit geography is the longitudinal drifts and longshore currents generated by the waves of the water bodies. These coastal features arise when the longitudinal drifts reach the section of a headland where the turn is greater than the angle of 30 degrees. The longitudinal drifts or the longshore waves continue the process of deposition above the water until water pressure from the sea or the ocean becomes more than the required amount for the formation of a spit geography. The spit and the geographic events influenced by the water become less pronounced as the spit stabilizes by the growth of vegetation as it grows more and more fertile. As the spits grow further the water behind them or rather trapped by them gets sheltered by the dynamic activities of the waves and the wind making it more suitable for a salt marsh to be developed. The growth of this vegetation is because of the sediments making up the spit which come from different sources, such as rivers, oceans, seas, etc. Whenever there is an increase in logging and activities like farming upstream of the water bodies can cause an increase in the sediment deposition as it increases the sediment load of the rivers as well. When the supply of the sediment is usually interrupted at the neck of the spit, the spit starts moving away from the land and it leads to the formation of an island.
Spits Around the World
The two of the famous spits around the world are shown in the below list of diagrams:
Curonian Spit: It is a spit divided between Russia and Lithuania.
[Image will be Uploaded Soon]Dungeness Spit: This spit is located in the Strait of Juan de Fuca on the US pacific coast.
[Image will be Uploaded Soon]Farewell Spit on the South Island of New Zealand
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Other famous spits around the world include the longest spit in the world which is the Arbat Spit located in the Sea of Azov with a length of 110 kilometers approximately. The longest spit found in a freshwater body is in Long Point, Ontario extending approximately 32 km into Lake Erie.
FAQs on Spit - Coastal Feature
1. What exactly is a coastal spit in geography?
A coastal spit is a long, narrow strip of land made of sand or shingle. It is formed by the deposition of sediment by the sea. A spit is always connected to the mainland at one end and extends out into the open water, such as a sea or a lake. It is a classic example of a depositional landform.
2. How is a coastal spit formed step-by-step?
A spit is formed primarily by a process called longshore drift. Here’s how it happens:
- Waves hit the coast at an angle, carrying sediment (like sand and pebbles) along the shoreline.
- When the coastline suddenly changes direction, such as at a river mouth or a bay, the water loses energy.
- This loss of energy causes the water to drop the sediment it was carrying.
- Over time, this deposited material builds up to form a long ridge that stretches away from the coast, creating a spit.
3. Can you give some real-world examples of spits?
Yes, there are many famous spits around the world. Some well-known examples include:
- Spurn Head in Yorkshire, UK.
- Farewell Spit in New Zealand, one of the longest in the world.
- Homer Spit in Alaska, USA.
- In India, a spit is seen to be developing near the Kakinada Bay in Andhra Pradesh.
4. Why do some spits have a curved or hooked end?
The curved or hooked end on a spit is usually caused by changes in wind and wave direction. As the spit grows longer and extends into open water, it becomes more exposed to waves from different directions. Secondary waves or changes in wind can cause the end of the spit to curve inwards towards the land, a process known as wave refraction. This gives it a characteristic 'hooked' appearance.
5. What is the difference between a spit and a tombolo?
Both are depositional landforms, but their connections are different. A spit is connected to land at only one end and extends into the water. A tombolo is a special type of spit that has grown long enough to connect the mainland to a nearby island, forming a land bridge.
6. What happens if a spit grows all the way across a bay?
If a spit grows completely across the mouth of a bay, it connects two headlands and is no longer called a spit. It becomes a bar or a baymouth bar. This bar can trap a body of water behind it, which then forms a calm body of water known as a lagoon.
7. Are coastal spits permanent features of a coastline?
No, spits are highly dynamic and unstable landforms, not permanent ones. Their shape and size are constantly changing due to the balance between sediment deposition and erosion. A strong storm can damage or destroy a spit, while a steady supply of sediment can cause it to grow longer over time.
