case studies

• North yorkshire coastline is located in the north east of England and stretches over 60km from Saltburn to Flamborough head
• the geology by the north York moors is mainly sandstone, shales and limestone but by Flamborough head it is predominantly chalk
• the fetch is about 1500km with the dominant wave direction coming from the north west. This leads to the area Saltburn having the most erosive forces
• erosion rate for clay/shale is 0.8m p/year while in the limestone areas it is 0.1m p/year
• sediment sources

  Sediment form the cliffs due to erosion and from the river Esk
• Wave height is 4m in the summer this is helped due to significant longshore drift
• foreshore plain= characterised by elongated ridges, running almost parallel to the shoreline alternating with lagoons, salt marshes and alluvial deposits
• the frontal plain= south of foreshore plain and is scattered with eroded limestone and clay deposits
• the sandy zone is composed of a variety of different sand formations, sheets, dunes and hummocks
• impacts of the Aswan high dam

  blocks sediment from reaching down to the delta and therefore stops the delta from flooding. This changes the shape of the shoreline as there is increased erosion and increased coastal retreat (140m/year)
• impacts of waves

  wave action in the Mediterranean redistributes the sediment at the front of the delta which forms a series of bars that then close off to form lagoons
• impacts of the wind

  north west wind enhances the constant movement of water and sediment.

  during the summer velocity reaches 9-13cm/s and in winter 23cm/s
• 1/3 of new zealands total population is in Auckland so they use sand in Mangwhai Pakiri to help with beach recharge and for constructio
• Unintentional changes

  Mining of the sand depletes it moving between sediment cells

  The sand is not being replaced due to lack of river deposists

  Erosion increased from dredging forAuckland
• Increased coastal erosion and decreasing natural protection
• Long term retreat at 35m by 2100
• The beaches are becomming more flatter and wider which make them vulnerable to erosion from high energy waves
• 1978 a storm broke through a spit which then altered the tidal current and increased sediment into the harbour