Key terms Flashcards
Fetch
The distance of open water over which a wind blows interrupted by major land obstacles.
Helps determine the magnitude and energy of the waves reaching the coast
Mass movement
The movement of material downhill under the influence of gravity, but may also by assisted by rainfall
Backwash
The action of water receding back down the beach towards the sea
Constructive waves
Low wave height
Long wavelength
Low frequency
Swash tends to be more powerful than their backwash
As a consequence material builds up on the beach
Destructive waves
High wave height
Steep from
High frequency
Backwash is generally stronger than their swash so more sediment is removed than added
Swash
The rush of water up the beach after a wave breaks
Longshore drift
Where waves approach the shore at an angle and swash and backwash then transport material along the coast in the direction of the prevailing wind and waves
Wave refraction
When waves approach a coastline that is not a regular shape, they’re refracted and become increasingly parallel to the coastline.
Overall effect is the majority of the wave energy is focused on the headland and the low energy waves spill into the bay, resulting in deposition
Tides
The periodic rise and fall of the level of the sea in response to the gravitation pull of the sun and the moon
Coastal sediment budget
The balance between sediment being added to and removed from the coastal system, that system being defined within each individual sediment cell
High energy coast
Strong, steady prevailing winds create high energy waves and the rate of erosion is greater than the rate of deposition
Low energy coast
Wave energy is low and the rate of deposition often exceeds the rate of erosion
Sediment cell
A distinct area of a coastline separated from other areas by well-defined boundaries, such as headlands and stretches of deep water
Marine processes
Operate upon a coastline and are connected with the sea, such as waves, tides and longshore drift
Sub-aerial processes
Processes that slowly break down the coastline, weaken the underlying rocks and allow sudden movements or erosion to happen more easily
