Coastal systems

  Coastal systems

Keerthana

28/08/20

Theme:change

The coastal system, what is the first thing you think about when you read this terminology? It already gives out the hint that it is something related to the coasts (beaches), oceans and the processes which occur there. It is a dynamic environment and so is the river system also.

The coast is the place where the sea meets land like a beach, it is an open system. With this, lets contrast and find the similarities between a river system and a coastal system, just to jog your memory of the previous blog cause you’ll find many similarities and differences between these two systems just like a couch and a chair. First, lets do two differences, coastal systems, as the name suggests is involving sea or the ocean, which means it is on a large scale but the river system is a small scale process ( but this can wreck havoc, it ain’t as innocent as it sounds). Also the same erosion cycle happens in both the systems but at different rates. Now coming on to the contrasts, a river system has an inlet and an outlet of water but the coastal system has neither an inlet or an outlet(open system). And also, there are no stages in an ocean like a river ( only one can be dramatic apparently) so the erosion is affected to different external factors.

Now, on to the landforms and the external factors erode the rock. Since, if I explain each stage of the rock during erosion you might get bored cause I am warning you, it will be one long lecture and no one likes that, i will just give a brief.

Small crack<sea cave< sea arch< head land< stack< stump< wave cut platform< bay

Just imagine waves, the force of the wind hitting the cliff, the land repeatedly and it slowly breaking away from the land like this.

(This is a stack and soon after years of eroding, all that would be left is sediments to form the bay)

The question arises, how theses erosion differs in the two systems? In the coastal systems, the waves, the wind current and tides are the factors responsible for erosion. The frontal movement of the wave is called swash and the receding movement of the wave is called backswash. The swash is much more forceful than backswash in constructive waves and the opposite in destructive waves, swash comes at the beach from an angle unlike the backswash which goes back in a straight line.

Constructive waves are the waves that come in with a lot of energy and erosion done is much more faster. Destructive waves are the waves that lose their energy very fast and erosion done is less compared to the constructive waves. The direction of the waves are influences by prevailing winds.

 Coming on to a couple of more landforms created by erosion. The first is the shore that is created by long shore drift  ( the movement of material along the coast by waves that approach at an angle but recede directly back). A sand bar is an area of load (sand, gravel and silt) that is formed by longshore drift, A sand spit is a ridge of sand from the mainland to bay. The other landforms are lagoons, bays and tombolos. 

This is all for today, didnt want to make it too long. In the next blog I’ll conclude this series of blogs with the impact of the erosion cycle.