For my coursework I will study coastal erosion on the Walton-on-the-Naze cliffs in Essex. This is a coastal resort located about 10 miles from Frinton-on-Sea and is a two hour drive from North London.
The aim of the study is to investigate the differences in beach characteristics in the managed and unmanaged sections of the beach at Walton-on-Naze. I have chosen to study this topic of coastal erosion in order to identify variations in beach characteristics and how badly and sea walls cliffs can erode in the past years. If they lack protection like groynes.Our visit to Walton-on-the-Naze came on 21st May 2008.
It was a good idea to do it just at the beginning of the summer because there not would be too many tourists to interfere with our progress but the weather would still most likely be good which would help to gather and record accurate results. (This the map of Essex in which Walton-on-the-Naze is located) I am interested in the difference in the beach characteristics between the managed and unmanaged sections, the probable processes operating there and in whether the council should consider changing or adding to its sea defences in this areaGeology plays an important part in how the cliffs are eroded at Walton-on-the-Naze so I will describe how this happens. Slumped material effectively helps to protect the cliff in the short term or long term if it can be coloruzed by vegetation. However it is generally taken away by the action of long-shore drift, and the whole process starts again.
The erosion of the relatively unresistant cliff materials at Walton-on-the-Naze has led to the need for a sea wall, groynes and other defences to protect the town and tourist interests of Walton-on-the-Naze.However tendring Council has only used these defences in what I will call the managed section of the coast because the town has directly behind it the unmanaged coast to the north and its cliff are unprotected because there is no settlement behind and it is not considered economically sound (cost effective) to build defences there. What is Coastal Erosion? Erosion is when wind, water, and ice wear away the of land. Sediment is made of rocks, dirt, and earth.
Erosion by wind action occurs mostly on beaches and in deserts, because there is no continuous vegetation or plants.Wave erosion, which occurs along beaches and coasts, such as Walton-on-the-Naze is caused by the impact of breaking waves on the shore and cliffs. Both wind action and water action have important parts in this process and constantly help to change the boundary between land and water. Coastal erosion takes land away from one area to deposit it someplace else.
There are four main processes by which the sea can erode the land; these are similar to those of a river. Hydraulic pressure is the sheer force of the waves, especially when they trap and compress air in cracks and holes in a cliff.Corrosion results from large waves hurling beach material against the cliff. Attrition is when waves cause rocks and pebbles on the beach to bump into each other and to break down in size.
Corrosion is when certain types of cliff are slowly dissolved by acids in the sea water. Material is transported along the beach in a zigzag movement of the beach the net movement being referred to as the long shore drift. Coastal areas are managed because the land behind area is worth saving.They are managed with sea walls, groynes, cliff grading movement and other types of defences.
Mass movement is when the water erodes the cliff face and causes it to move back two metres a year. What I expect to see on Walton-on-the-Naze is a lot of broken material in the unmanaged section because of the lack of coastal management due to the erosion of the cliffs. Method One of my investigations is to look at the sediment and the both managed and unmanaged sections. The equipment that I used was: * A spade * A leveller * A bowl A weighing scale * A sieve * A bucket * Measuring Tape * A tube * 2 ranging poles I measured sediment in order to see which section of the beach has bigger pieces of sediment (larger than 5cm in diameter) by measuring how much material is in the sand.
We did this by digging up the sand from one area and then strained out the sand and weighed the remaining stomy material that’s left with a scale. I think that the managed section has more material in it as the groyne’s stop the movement of the material. This test will help me too rove my prediction that rocks will be smaller in the managed section than the unmanaged sections because large bits of the cliff fall off the cliff fall off in the unmanaged section which means the rocks there to form bigger pieces than an the managed section. Diagram 1 Diagram 2 Diagram 3 Diagram 4 Diagram 5 Diagram 6 For the beach profile test, my graphs show that the managed section was higher than the unmanaged section because the highest that the unmanaged section was 116.
17 but the highest that the unmanaged section was at was 84. 17.So it is obvious that the managed section was higher than the unmanaged section by quite a lot as the difference between the two numbers 116. 17 and 84.
17 is 32. The managed section was higher because the groyne’s prevent long shore drift from happening. For the infiltration test, my graphs shows that the managed section infiltrated more water than the unmanaged section as the highest amount that was infiltrated in the managed section was 25. 50cm and the highest that was infiltrated in the unmanaged section was 24.
00cm. The difference between the two (managed and unmanaged) infiltration rates is not a lot as it is only 1. 0cm. The managed section infiltrated more water than the unmanaged section because there is larger material in the managed section, as the groyne’s stop the material from being transported and further eroded.
The air gaps between the shore is there grade allowing a higher infiltration rate to be recorded there.For the beach sediment test, my graphs show that the managed section has smaller material in it and the unmanaged section has larger material in it. The highest amount of sediment in the unmanaged section was 11000. 00g and the highest in managed section was 350.
0g this is a big difference. The unmanaged section has larger material in it than the managed section because big bits of rock are falling down from the cliff onto the unmanaged section of the beach, due to mass movement but all the material in the managed section is smaller because it has transported there by long shore drift and has caused the rocks to be smaller. In my data there is a pattern as the managed section infiltrated more water, this is because there is more material in the managed section of the beach than the unmanaged section so it absorbs more water.My results are not 100% reliable as we only have a few bits of data.
In the infiltration test the tube wasn’t always put into the sand at the same distance so this made the test a bit unfair, and when we put the tube into the sand some of the water kept on leaking out. Also in the beach profile test the two ranging poles were not always put into the sand at the same distance so this is another factor that made the test less reliable, and the people holding the ranging poles were not always holding the poles straight.In the beach sediment test the sand collected at each point wasn’t completely the same so this also decreases the reliability of the results. To make my results more accurate data, we could measure the amount of sand that we collect in the beach sediment test using a measuring jug so that we always get the same amount of sand at each point making it a fair test.
In the infiltration test we could measure how far we put the tube into the sand using a ruler at each point; also we could stop the water from leaking by making sure there are no holes before we pour the water into the tube therefore making our results more reliable.Another way in which we could avoid this problem is by re-doing this test again in a different location and hopefully this problem will not occur again. In the beach profile test we can measure how far we can put the ranging poles into the sand at each point so that we can put them all in at the same distance, also we could make sure that the people holding the ranging poles are holding them straight this would make our results more reliable.Another way we could have used to improve our results is by using clinometers or more scientific equipment like ab ney levels.
This would make our results more accurate as it measures the gradient and can also be mounted. Another thing that we could have done to make our results more accurate is to make sure that we have enough time to make all the measurements, because last time we rushed the experiments that we were doing as the tide was coming in soon, and for those that didn’t get to record all the data they may have recorded wrong data.