Coastal Management: Soft Engineering

Coastal Management: Soft Engineering

1. Beach Replenishment

   • The building up of beaches, often using sediment dredged from an offshore sediment sink the raised beach absorbs and dissipates energy
   • There has to be a periodic replenishment for the defence to maintain its effectiveness
   • Preston Beach: to prevent storm waves overtopping the sea wall and causing flooding. the beach was built up to an average width of 60 metres from an average width of 10 metres. the beach was eroded back to 20m wide within 6 years
   • Hurst Castle Spit: 60,000 tonnes of shingles added to make the spit an average of 7m above the mean sea level in 1989 to prevent storm waves from overtopping the spit

2. Regrading Cliffs

   • reducing the gradient of a cliff to a more stable angle, to reduce the stress operating on the rocks and reduce the risk of mass movement
   • Barton-On-Sea and Furzy Cliff

3. Dune Stabilisation

   • vegetating dunes by planting marram grass which stabilizes the sand, reducing erosion by wind, waves and people trampling over dunes
   • South Haven Peninsula, Studland and at Mudeford spit. Hengistbury Head: attempts made to stabilise parts of the cliff face by installing geo-textile netting and vegetating the cliffs

4. Managed Retreat

   • The cost of defending coastlines is enormous and will continue to increase due to rising sea levels and more frequent and intense storms occur putting the coastlines at risk. continuing to build defences is becoming unsustainable.
   • The managed retreat policy is being adopted more frequently due to rising costs. strategic stretches of coastline are being defended while others are left for the sea to erode
   • In some places local authorites are drawing a red line on a map where they see the coastline at a future date. Any land seaward of this line will be left to the sea. In some cases the defences located on this part of land will be breached on purpose to let the sea invade and speed up the process.
     • Very controversial policy as the current laws do not allow for compensation for the land that is lost to the sea.
     • Lincolnshire: this policy has already resulted in coastal defences being breached and the sea has flooded hundreds of acres of land