Factors Influencing Coastal Processes

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Factors Influencing Coastal Processes

In this essay I aim to describe and explain factors affecting coastal

processes. I will focus and explore how waves, tides, winds and mass

movement processes can change the form of the coasts within our

lifetime. The three key questions I will focus on are:

* What are the energy and sediment inputs into the coastal system?

* What are the processes that erode coasts?

* How is sediment transported and deposited?

I will conclude by describing and explaining factors influencing

coastal processes and how they make up the South Dorset coast.

The littoral zone is a narrow zone between high and low water zones

where energy and sediment concentrate. The sediments on the coast are

sand, shingle and clay. The river, cliffs and sea are sources of

sediment inputs into the coastal system. (Fig. 1)

(Fig 1. Sediment inputs into the coastal system.)

The energy inputs include wind, waves and tidal currents. The wind

produces sand dunes on beaches with shallow offshore gradients; these

produce ecosystems, which help with plants that cope with lack of

nutrients and water etc. Sand dunes help absorb the pounding of high

waves and reduce over wash flooding in storms. Below is a diagram of

Studland Dunes and beach, showing the different parts of the beach (Fig.

2)

Fig. 2 Studland dunes and beach

[IMAGE]

Winds create waves that ripple across the surface of lakes and seas

until they break on the shallowing bottom and crash into the shore. In

many areas, prevailing winds produce waves that consistently approach

the coast at oblique angles. Even the slightest angle between the land

and the waves will create currents that transport sediment along the

shore. These longshore currents are a primary agent of coastal

movement; they are a major cause of sand migration along barrier and

mainland beaches. (Fig 3)

Fig 3. Fistral Beach, Newquay, Cornwall UK

[IMAGE]

Tides ebb and flood in response to the gravitational attraction of the

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