Sources of energy in coastal environments

Wind

Primary source of energy for other processes including erosion, deposition and transport- created by air moving from areas of high pressure→ low pressure

Fetch

Refers to the distance of open water over which a wind blows uninterrupted by major land obstacles

Wave height

The height difference between a wave crest and the neighboring trough

Wavelength

The distance between two successive wave crests

Wave frequency

The time for one wave to travel the distance of one wavelength

Backwash

The action of water receding back down the beach towards the sea

Constructive waves

Waves with low wave height, long wavelength and low frequency. Their swash tends to be more powerful than their backwash, as a consequence beach material builds up

Destructive waves

Waves with a high wave height, a steep form and a high frequency. Their backwash is stronger than their swash so more sediment is removed than added.

Swash

The rush of water up the beach after a wave breaks

Longshore currents

occur as waves hit beach at an angle, generates a current running parallel to the shore, this transports sediment along the shore

Rip currents

Strong currents moving away from the shore, initially running parallel as water is trapped between the incoming waves and the land. After running parallel it goes out to sea beyond the breaker zone, extremely hazardous to swimmers

Upwelling

Movement of cold water from deep in the ocean towards the surface. Replaces warm surface water and creates nutrient rich cold ocean currents.

Tides

Periodic rise and fall of the level of the sea in response to the gravitational pull of the sun and moon

Spring tides

Where the Earth, moon and sun are all in line and causes large bulges of water, it has the highest monthly tidal range, occurs twice a month

Neap tides

Where the Earth, moon and sun are perpendicular, it has the lowest monthly tidal range, occurs twice a month