Underlying the Holderness Coast is bedrock made up of Cretaceous Chalk. However, in most places, this is covered by glacial till deposited over 18, years ago. It is this soft boulder clay that is being rapidly eroded. There are two main reasons why this area of coast is eroding so rapidly. The first is the result of the strong prevailing winds creating longshore drift that moves material south along the coastline. The second is that the cliffs are made of soft boulder clay which erodes rapidly when saturated.
The Holderness Coast is a great case study to use when examining coastal processes and the features associated with them. The exposed chalk of Flamborough provides examples of erosion , features such as caves, arches and stacks. This is because material which is being carried south is not being replaced it is trapped within the groynes. Therefore there is no beach to protect the cliffs. Sea defences mean that the beach has grown and the cliffs are stable look at the grass growing!
Aldbrough Aldbrough is a small settlement to the south of Mappleton. Where Mappleton had substantial sea defences built, Aldbrough has none. The cliffs here are rapidly eroding. Some residents think that the sea defences at Mappleton has made things worse. Why would they think this? Aldbrough Withernsea This settlement attracts tourists, so substantial sea defences have been constructed to maintain the beach.
How many sea defences can you see in this picture? Withernsea — how does it all work? Kilnsea The old settlement of Kilnsea has now been completely lost. Sea defences were built here in the early s to protect the Godwin Battery - a defensive gun emplacement and the rail-head for a light railway to further military installations on Spurn point.
The sea defences are now crumbling and erosion is progressing rapidly. Kilnsea Old map of Kilnsea Current aerial photo of Kilnsea Spurn Head The area known as Spurn forms the southern extremity of the Holderness coast and includes the unique feature of Spurn Head, a sand and shingle spit 5.
Spurn is made up of the material which has been transported along the Holderness Coast. This includes sand, sediment and shingle. How would sea defences along the coastline affect Spurn? Spurn Head 1. The material eroded from the Holderness cliffs is swept southwards. North easterly waves move the coarser sands and gravel down towards the mouth of the Humber 3.
The finer sands and clays are swept offshore and continue southwards towards the Wash. In the past Spurn Head seems to have grown and been washed away in a regular cycle, slowly moving towards the east to keep pace with the erosion of the Holderness cliffs. For over years the position of Spurn has been fixed by artificial sea defences. These defences are now falling into disrepair and the sea is starting to erode parts of the peninsula once again.
Spurn Head Spurn Head changes position. Most of the spit has flexible road surfaces, which are like mats that can be picked up and moved following major storms. There is plenty of evidence of this movement. Former railway tracks that were built to move building materials along Spurn for the building of Bull Fort in the Humber Estuary now appear to lead into the sea. Spurn Head Is Spurn eroding? The end of Spurn is fairly stable.
The rest of Spurn erodes and moves constantly. There are some groynes to protect it, but these are very old now. Spurn Head Is it important to protect access to Spurn Point? Full time lifeboat men live here with their families. The Humber estuary is very busy with large ships. It is one of the most dangerous estuaries in Europe, so pilots guide boats in and out. Their base is on Spurn for quick access to sea.
The pilots do not live on Spurn. Spurn is also important for birds and wildlife. Coastal management at Withersea has tried to make the beach wider by using groynes, and also a seawall to protect the coast.
Mappleton is protected by rock groynes. Spurn Head is protected with groynes and rock armour. Conflicts There has been an increase in erosion at Great Cowden because of the groynes used in Mappleton. This has led to farms being destroyed by the erosion and the loss of chalets at the Golden Sands Holiday Park. However some defences have been attempted. Mappleton is a small village that could become village number 30 lost to the sea.
The road running through it, the B links towns along the coastline and would have been lost to coastal erosion if protection measures were not put into place. It was decided t6hat the cost of coastal defence for a village of only people was less than the cost of building a new road. So, blocks of granite were brought in and placed along the cliff base and 2 rock groynes were put into place to trap sediment moving because of longshore drift. Open this Word document and complete all of the tasks using the Google map below ; Find out more about coastal erosion at this excellent website.
Geology The geology runs in bands, with a chalk layer at Flamborough in the North, Boulder clay or till laid down in the last ice age south of that and finally river deposits in the Humber Estuary.
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