Beaches are continuously changing – from day to day, month to month and year to year – as the natural forces of wind and water meet the land. These changes, which have been taking place for millions of years, are linked to variations in wind, waves, currents and sea level height.
But it is not just natural forces that change the beach, humans have a big role to play in this process as well, through mining stones and sand from the beaches and dunes, polluting and damaging coral reefs, and constructing buildings and walls too close to the sea.
Changes in the beaches affect everyone. The coast is a place we are all attracted to for recreation, sports and simple enjoyment. This constantly changing and hazard-prone coastal environment is also where the greatest financial investment is concentrated, as large tourism properties and establishments continue to be attracted towards Anguilla's shores. Tourism is a driving force in Anguilla’s economy so the state of its beaches is of major importance.
Natural forces
• Hurricanes and tropical storms, occurring between June and November, cause dramatic beach changes usually resulting in serious beach erosion.
• High waves in winter resulting from storms in the North Atlantic Ocean, and known as swell waves, or locally as ‘groundseas’.
• Sea-level rise, which is a long-term factor, taking place very slowly over decades causes shorelines to retreat inland. Since 1995, the Atlantic Basin (including the Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico) has entered a more active hurricane cycle, which may continue for more than 20 years.
Human Fiorces
• Removing sand from beaches and dunes for construction purposes causes erosion and the loss of beaches and coastal lands, destroying the natural heritage of the coast and reducing the vibrancy of the tourism industry.
• Building too close to the beach interferes with the natural sand movement and may impede beach recovery after a serious storm or hurricane. • Badly planned sea defences may cause the loss of the beach, and of neighbouring beaches.
• Pollution from human activities on the land may damage coral reefs and seagrass beds; these biological systems protect, and provide sand to the beaches.
• Removing vegetation from the dunes destabilises these protective sand barriers; and clearing sites inland results in increased soil and dirt particles being washed offshore and smothering coral reef systems.
There are many ways to combat the threat of coastal erosion. Which is the action of the sea in causing damage to the coast. i.e. cliff collapse or the washing away of beaches.
Hard Engineering
Hard Engineering involves building structures to protect the coastline.
- Sea Wall: Placed at the base of a cliff to reflect the waves energy.
- Gabions: Cages of wire filled with rocks to absorb the waves energy.
- Groynes: Can be made of wood or rock and are long vertical structures placed at right angles to the beach to trap sediment. This builds up the beach and protects the cliffs from erosion.
- Rip Rap (Rock armour): Large rocks placed at the bottom of the cliff or artificial spit to absorb the wave energy, they are effective at dispersing the waves energy
Soft Engineering
Soft Engineering is a less environmentally noticeable way of managing the coastline.
- Beach Nourishment: Large amounts of sand are added to beaches to build them up and help absorb wave energy. T
- Managed Retreat: This allows the natural erosional processses of the sea to occur, areas of low value land are allowed to flood hopefully protecting more important areas further down the coast.
- Cliff Stabilisation: Cliffs are covered in matting and vegetation planted to help make them more stable and resistant to erosion.
- Do nothing: Just let that nature do what they want.
Types of Rocks
Sedimentary
Sedimentary rocks are formed on the surface of the Earth, either in water or on land. They are called secondary, because they often result from the accumulation of small pieces broken off from pre-existing rocks. Most sedimentary rocks become cemented together by minerals and chemicals present when they are formed, and others are held together by electrical attraction. Some, however, remain loose, crumbly and unconsolidated. Gravel is an overall name for large sediment grain size, which includes boulder, cobble, and pebble. Sandstone and limestone are examples of sedimentary rocks.
Igneous
Igneous rocks get their name from the Latin word ignis, meaning "fire." Under the surface of the Earth the magma is kept liquid by high temperature and high pressure. As the volcano erupts hot magma reaches the surface. Afterward the lava rapidly cools down and solidifies. The crystals formed by cooling magma are usually small. Magma doesn't always reach the surface. Sometimes it is trapped underground in pockets inside of other rocks. In this case the magma cools down more slowly forming larger crystals and coarse-grained rocks. Visible crystals or phenocrysts are an easy way to identify an igneous rock. An example of an igneous rock would be granite.
Metamorphic
Sedimentary and igneous and metamorphic rocks which were subjected to intense pressure and/or heat and as a result underwent a complete change. Metamorphic rocks form deep within the Earth's crust. The process of metamorphism does not melt the rocks, but transforms them into other rocks which are denser and more compact. n example of an igneous rock would be marble and schist
To log this cache.
To get to log this cache you will have to visit and answer the questions which are related to the coordinates given the earthcache.
When answers are collected, send them to CO for verification.
You can log immediately after answers are sent CO. If there are any questions about your answers CO will contact you.
Logs without answers to CO or with pending questions from CO will be deleted without any further notice.
Questions:
1. Answer the questions under by visiting the given Coordinates.
A. What kind of erosion do you see here, is it natural or human made?
B. What are the main factors for this erosion?
C. Looks at the cliff. What type of rock is it made off? Tell me how erosion affects it?
D. What would be the best action to take, to prevent erosion going further at this location?
2. Take a photo of you (face showing is not mandatory) or your gps from the location without revealing answers.
The picture must include the nearby shipwreck and your geocaching name (written on a piece of paper, on your phone / tablet, on your t-shirt, on your body, whatever).
If you visit this cache as "team", each photo needs to be with your own nick-name. Logs with team nicknames are not permitted and will be deleted.
These requirements are there to ensure you actually went to the location after this cache has been published. Re-using old vacation pictures are not permitted.
Any log that doesn't meet the requirements will be deleted!
Enjoy the beach and have fun.
Happy Caching!