What is a longshore current What are the effects of this type of current?

What is a longshore current What are the effects of this type of current?

Longshore currents develop when waves approach a beach at an angle (Figure 12.37). Longshore currents cause sediment transport called longshore drift. Longshore drift is the movement of sediments along a coast by waves that approach at an angle to the shore but then the swash recedes directly away from it.

Are longshore drift and longshore currents the same?

The main difference between longshore current and longshore drift is that longshore currents are the ocean waves that travel parallel to the beach whereas longshore drift is the transportation of sediments along a coast, parallel to the shoreline.

What does longshore drift cause?

Longshore drift causes spits to build up at the mouth of rivers. or at the end of a point of land. Longshore drift also builds barrier beaches and barrier islands. Barriers are long narrow strips of sand and gravel that are separated from the main shore by lagoons, marshes and mud flats.

How waves and currents are affecting the beach over time?

The breaking waves and resulting currents pick up and move sand, making beaches dynamic, perpetually in motion. For example, sand eroded from the beach during winter storms may move offshore to form a sandbar. That causes waves to break farther offshore, protecting the beach from further erosion.

How are beach drift and longshore current similar and different?

The movement of sand along the shoreline is known as beach drift. The thicker blue arrow represents the waves approaching the shoreline at an angle. The narrower blue arrows show the current that develops as a result of the waves hitting the coastline at an angle. The current is called longshore current.

How does longshore drift affect beach morphology?

Longshore drift is a process responsible for moving significant amounts of sediment along the coast. The swash moves beach material along the beach and the backwash, under gravity, pulls the material back down the beach at right angles to the coastline. Over time this creates a net shift of material along the coast.

Is longshore drift erosion?

Longshore drift is the movement of material along the shore by wave action. Longshore drift happens when waves moves towards the coast at an angle. Longshore drift provides a link between erosion and deposition. Material in one place is eroded, transported then deposited elsewhere.

How waves affect the shoreline of the beach?

As waves hit the shoreline over time they erode it and push it further inland. When larger and stronger waves hit the shoreline, such as in a storm, more shoreline is eroded.

How do waves impact the beach?

Waves will spread the sediments along the coastline to create a beach. Waves also erode sediments from cliffs and shorelines and transport them onto beaches. Waves continually move sand along the shore and move sand from the beaches on shore to bars of sand offshore as the seasons change.

How does longshore drift affect the land around it?

Longshore drift causes spits to build up at the mouth of rivers or at the end of a point of land. Longshore drift also builds barrier beaches and barrier islands. Barriers are long narrow strips of sand and gravel that are separated from the main shore by lagoons, marshes and mud flats. Sometimes people will build fences…

How does the longshore current affect the water?

The incoming wind that comes with the longshore current squeezes the water along the coast and generates a water current that is parallel to the shoreline. Here, the sediments that come with water can remain on the beach; sometimes, the sediments on the beach can move off the beach with the water current.

What causes sediment to move on the beach?

Longshore drift is a result of longshore currents that approach the beach. The movement of longshore currents towards and backwards the shoreline causes the sediments to move on and off the beach. Here, the most common sediment materials include clay, silt, pebbles, shingle, etc.