Coastal Erosion -Brooms Head EarthCache
Coastal Erosion -Brooms Head
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This Earthcache is situated on the coastal beach at Brooms Head There is parking available close by for day users to the area There is no need to go off the footpath to view the area If you have children please keep an eye on them as road can be busy at times and also water is just a few metres away
WHAT IS COASTAL EROSION ? Coastal erosion involves the breaking down and removal of material along a coastline by the movement of wind & water. It leads to the formation of many landforms and, combined with deposition, plays an important role in shaping the coastline. METHODS OF EROSION Hydraulic Action: When a wave impacts a cliff face, air is forced into cracks under high pressure, widening them. Over long periods of time, the growing cracks destabilize the cliff and fragments of rock break off of it. Corrosion/Abrasion: The repeated action of waves breaking on a cliff is enough to remove material from it over time. If sand & shingle are present in the water, it will act like sandpaper and erosion will take place faster. Attrition: Beach material is knocked together in water reducing their size and increasing their roundness & smoothness. Corrosion Carbon dioxide in the atmosphere is dissolved into water turning it into a weak carbonic acid. Several rocks (e.g., Limestone) are vulnerable to this acidic water and will dissolve into it. The rate of dissolution is affected by the concentration of carbonates & other minerals in the water. As it increases, dissolution becomes slower. FACTORS AFFECTING THE RATE OF EROSION The biggest factor affecting coastal erosion is the strength of the waves breaking along the coastline. A wave’s strength is controlled by its fetch and the wind speed. Longer fetches & stronger winds create bigger, more powerful waves that have more erosive power. As waves approach a coastline they lose energy though because friction with the seabed increases. This means that the bathymetry (the underwater elevation) of the ocean or sea bed also impacts the strength of waves. Certain landforms further reduce wave’s erosive power. Beaches increase the distance a wave travels before it reaches the coastline’s cliffs and so reduces its energy. Headlands refract waves around them, reducing their erosive power at one location while increasing it at another. Weathering also plays a role in the rate of erosion by creating weaknesses in rocks that are exploited by the processes of erosion. Freeze-thaw weathering, for example, creates cracks in rocks, increasing the rock’s susceptibility to hydraulic action. As always, humans have an impact on coastal erosion. Human activities have a variety of complex effects on coastal erosion but most commonly the activities increase the strength of waves. One activity, dredging, is commonly carried out to improve shipping capacities but it reduces the amount of energy dissipated from incoming waves and so increases erosion As you walk along the path to gz you will notice a rock wall placed to hold back the water and stop land erosion Boulders of sandstone and conglomerate have been used to protect the shoreline from erosion In the distance you will also see a rocky outcrop This rocky shorelines are not only vital to marine life or roosting and breeding local and migratory birds but also most importantly the rocky shoreline helps stabilize sediments and protect the coast from powerful waves that roll in Take the time to stroll along the path and read about the area Locals will tell you that the beach is gradually being eroded away To log this cache please send me your answers to the questions below You can log after doing so Q1 Do you think the rock wall is affective in helping with coastal erosion ,and if so how? Q2 How affective would this wall be if there was a storm or high tides ? Q3 What type of erosion do you think would occur here Q4 At ground zero is a rock you are able to stand on ,what is the difference of this rock to others surrounding it ie.size,shape This question is to verify if you are at the sight Hope you enjoy your visit to Brooms Head
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