What is longshore drift and how does it occur?

What is longshore drift and how does it occur?

Waves that hit the beach at an angle carry sand and gravel up the beach face at an angle. When the water washes back the sediment. is carried straight back down the beach face. Individual particles are moved along the beach in a zig zag pattern. This is called longshore drift.

What influences longshore drift?

Longshore drift is influenced by numerous aspects of the coastal system, with processes that occur within the surf zone largely influencing the deposition and erosion of sediments. Longshore currents can generate oblique breaking waves which result in longshore transport.

Where does longshore drift occur?

surf zone
Longshore drift is simply the sediment moved by the longshore current. This current and sediment movement occur within the surf zone. The process is also known as littoral drift. Beach sand is also moved on such oblique wind days, due to the swash and backwash of water on the beach.

Why do people stop longshore drift?

Groynes control beach material and prevent undermining of the promenade seawall. Groynes interrupt wave action and protect the beach from being washed away by longshore drift. Longshore drift is the wave action that slowly erodes the beach.

What is evidence of longshore drift?

The transport of sand and pebbles along the coast is called longshore drift. The prevailing wind (the direction the wind ususally blows from) causes waves to approach the coast at an angle. The swash carries the sand and pebbles up the beach at the same angle (usually 45º).

Why are coastlines not straight?

wave erosion Particles are dragged back and forth by wave action, abrading the bedrock along the coast and abrading each other, gradually wearing pebbles into sand. Thus, features extended out into the lake will receive more wave energy, and the tendency is to smooth out an irregular coastline.

Is a beach erosional or depositional?

Wave Deposition 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. Beaches can be made of mineral grains like quartz, rock fragments, and also pieces of shell or coral (Figure below).

How does longshore drift work on the beach?

Longshore Drift Longshore (littoral) drift is the movement of material along the shore by wave action. It happens when waves approach the beach at an angle. The swash (waves moving up the beach) carries material up and along the beach.

Which is an example of longshore drift and a spit?

Groynes can be built to interrupt the flow of longshore drift, but inevitably some sand and gravel can escape. Longshore drift can form spits were the line of the coast changes sharply, for example at a river estuary. There are several examples of spits along the Welsh coastline.

What kind of landforms are formed by longshore drift?

Longshore Drift. contributes towards the formation of a range of depositional landforms such as spits and onshore bars. Spurn Point is a coastal spit formed by the transportation of coastal sediment by along the Holderness Coast. This material is then deposited at the mouth of the Humber .

Why is the structuring of an inlet important for longshore drift?

The structuring of tidal inlets is also important for longshore drift as if an inlet is unstructured sediment may by pass the inlet and form bars at the down-drift part of the coast.