Managing Coastline

Managing Coastline

1. Hard Engineering

   • Sea Wall
     • wall made out of a hard material (concrete) that reflects waves back to sea
     • -Prevents Erosion -Barrier to stop flooding
     • -Creates Strong Backwash -Very expensive to build and maintain
   • Groynes
     • Wooden or Stone fences at right angles to the coast, trap material by LSD
     • - Create Wider Beach (slows waves) -fairly cheap
     • -Starve beaches at one end, creates narrow end -narrow beaches don't protect well
   • Rock Armour
     • Boulders placed along the coast
     • -Absorb wave energy reduce erosion and flooding -fairly cheap
     • -Can be moved by strong waves (need replaced)

2. Soft Engineering

   • Beach Nourishment
     • Sand and shingle from elsewhere added to beaches
     • -creates wider beaches (slows waves) -very natural
     • -taking material from seabed can kill organisms (corals) -very expensive and needs to be repeated
   • Dune Regeneration
     • Creating/ restoring sand dunes by either nourishment or planting vegetation to stabilise sand
     • -provide barrier between land and sea, wave energy absorbed - cheap
     • -Protection is limited -nourishment is expensive
   • Marsh Creation
     • planting vegetation in mudflats along coast
     • -vegetation stabilised the mudflats and helps reduce the speed of the waves -creates new habitats for organisms
     • -is not useful when erosion rates are really high -fairly expensive
   • Managed Retreat
     • removing existing defence and allowing land to flood behind it
     • -overtime land become marshland, new habitats -fairly cheap
     • -may disagree over what land should be flooded (farmland)

3. Case Study: Holdreness

   • Bridlington protected by a 4.7km long sea wall and wooden groynes
   • Hornsea: sea wall, wooden groynes and rock armour
   • withernsea: groynes creating wider beach
   • Mappleton- 2 rock groynes built in 1991, costing £2 million
   • East side of Spurn Head, groynes and rock armour to protect Humber Estuary
   • Problems
     • groynes make narrow beaches further down the coast (Cowden Farm at risk)
     • reducing the amount of sediment increase flooding, less material to slow the water down
     • Bays are forming between protected areas creating headlands which erode more heavily