Term 2A - Coastal Environments Flashcards
How do waves shape our coastline?
The energy carried through waves moves beach sediment and transforms beach shape.
What causes waves?
Wind moving from areas of high pressure to low pressure.
What is the size and energy of a wave influenced by?
- How long the wind has been blowing
- The strength of the wind
- How far the wave has travelled
Define fetch.
The area that wind passes over an area of open water. The larger the fetch the faster the wind, the bigger the wave.
Define backwash.
The backwards movement of water once a wave has broken.
Define swash.
The forward movement of a wave up a beach.
What are constructive and destructive waves?
Constructive waves are powerful waves with strong swashes that surge up a beach and can deposit material (stronger swash, weaker backwash).
Destructive waves are larger waves caused by storms at sea, which can have strong backwashes and can often destroy (erode) the beach (stronger backwash, weaker swash).
What problems did Sri Lanka’s coast face and how was it managed?
Problems:
* Pollution of inshore waters caused by discharging of untreated sewage
* Reclamation of mangroves and coastal wetlands
* The loss and degradation of coral reefs
* Damaging impacts of aquaculture
Solutions:
* Coastal Zone Management (CZMP) to address and solve these conflicts. It aims to improve the quality of the coastal environment, and promote economic development.
Give 3 examples of conflicts between coastal users.
- Wildlife want an unpolluted, safe and quiet environment
- Local residents want jobs, clean beaches, affordable housing and schools
- Tourists want beaches, hotels, B&Bs, entertainment, holiday homes, and marinas
- Employers want building space, offices, and factories
- Developers want areas by the sea for tourists—hotels, duplexes, golf courses
- Fishermen want harbours, unpolluted waters, and ease of access to the sea
- Farmers want well-drained land, sheltered from prevailing winds
- Government and Councils want to build offshore wind farms and coastal defences
- Transport companies want good road networks, well-connected ports and terminals
What are the causes of coastal flooding?
- Storm surges
- Tsunamis
- Climate change
How can coastal flooding be predicted and prevented?
- Early warning systems (forecasting) allow communities to prepare (evacuate or take shelter) before flooding occurs
- Two methods are used to help forecast coastal flooding:
- Past records (diaries, newspapers, government/council records etc)
- These will identify areas that are at high risk of flooding and their frequency
- Modern technology - GIS, satellite and computer monitoring, weather stations (local and national) etc
- These allow for forecasting and tracking potential hazard events i.e.
- Tropical storms - track the storm’s path and associated storm surge
- Earthquakes - size and position if underwater and possible tsunami outcome
- Both these methods of forecasting help officials to say when and where the event will occur
- It indicates the possible strength and scale of the flooding, and the likelihood of damage and death
Describe and evaluate groynes as a hard engineering strategy.
Groynes are barriers or walls built perpendicular to the shoreline, extending from the beach into the water. They trap sediment moving with longshore drift, helping to build up the beach.
Advantages: Help build up the beach, providing additional recreation space.
Reduce coastal erosion locally.
Disadvantages: Can cause increased erosion further down the coastline as they interrupt the natural sediment movement.
May be visually unappealing.
Describe and evaluate beach replenishment as a soft engineering strategy.
Beach replenishment involves importing and depositing sand or other sediments from elsewhere to restore a beach that has been eroded.
Advantages: Enhances the appearance and recreational use of the beach.
Provides a buffer from storm waves and flooding.
Disadvantages: Often temporary, requiring repeated application.
Can be expensive and may impact the source area from which the sand is taken.
What is a crest?
The top of a wave.
Define hydraulic action.
Erosion
The hammering of waves breaking up rocks.
