Enquiry Question 1 Flashcards
The littoral zone consists of…
The littoral zone contains many coastal sediments (pebbles and sand particles). Waves, currents and tides move these sediments around in a zone along the coast called the littoral zone, which is from the highest sea- level line (linked to high tides and storm waves) to shallow offshore waters (where the base of a wave first encounters friction with the sea bed). This zone is subdivided into backshore, foreshore, nearshore and offshore zones.
The littoral zone is one of dynamic equilibrium, due to the wide range of natural processes that interact within it:
- There are inputs of sediments from the sea and currents from rivers flowing off the land.
- Weathering and mass movement occur on the backshore.
- Constructive and destructive waves occur on the foreshore and nearshore, causing deposition and erosion.
- The tidal range affects all parts by determining where wave action takes place.
- Offshore currents and longshore drift may move sediments some distance along the coast.
How do human activities interfere with the natural processes that interact within the littoral zone?
- Dredging of rivers to make them deeper for shipping.
- Dredging if offshore areas to get sand and gravel for construction.
- The building of coastal defences against erosion and flooding.
When can rapid change occur in the littoral zone?
Rapid change can take place when there is increased energy in the natural processes or when the impacts of human activities are not carefully considered.
How can coasts be classified using long-term criteria?
Sections of coast can be classified into different types using a variety of criteria, such as geology, sea-level rise and fall, and land-level rise and fall, which cause long-term changes.
How can coasts be classified using short-term criteria?
Erosion and deposition cause short-term changes.
What will determine the landscape of the coast?
The amount of energy in the coastal environment will determine the landscape of the coast. This energy is mostly provided by waves, but also to some extent the weather (rain, wind and temperature), rivers and large and small-scale sea currents.
What are the characteristics of low-energy coasts?
- The waves are less powerful (constructive), calmer conditions, short fetches.
- Processes such as deposition and transportation occur. Sediments from rivers, longshore drift and nearshore currents.
- Landforms such beaches, spits, salt marshes, sand dunes, bars and mudflats form.
- Low-energy coasts are sheltered from large waves and the general location is lowland coasts and coastal plain landscapes.
- Some example locations are the Mediterranean Sea coasts and the East Anglian coast.
What are the characteristics of high-energy coasts?
- The waves are more powerful (destructive), storm conditions and long fetches.
- Processes such as erosion and transport occur. Sediments from eroded land, mass movements and weathering, offshore currents.
- Landforms such as cliffs, wave-cut platforms, arches, sea caves and stacks form.
- High-energy coasts are exposed to the largest waves and the general location is highland and lowland coasts that have a rocky landscape.
- Some example locations are the Atlantic coasts of Norway and Scotland and the Pacific coasts of Alaska and Canada.
How is geological structure responsible for the formation of concordant coasts?
Concordant (or Dalmatian) coastlines occur where the folding or arrangement of rock types on a large scale, lie in the same direction as the coastline
Define coast.
Land adjacent to the sea and often heavily populated and urbanised.
Define backshore zone.
Above high tide level and only affected by waves during exceptionally high tides and major storms.
Define foreshore.
Where wave processes occur between high and low tide marks.
Define nearshore.
Shallow water areas close to land and used extensively for fishing, coastal trade and leisure.
Define offshore.
The open sea.
