hard engineering

hard engineering

1. sea wall

   • a stone / concrete wall at the foot of a cliff or the top of a beach. usually have a curved face to reflect the waves back into the sea.
   • the effectively prevent erosion (hydraulic action).
   • they usually have a promenade for people to walk along
   • they reflect the wave energy instead of absorbing it
   • they are considered to be an eye- sore and are ugly and unnatural to look at, this may affect tourism in the area and economic intake.
   • they are expensive to build and maintain. They cost around £6000 per metre
   • this is not very sustainable as it requires regular maintanance

2. groynes

   • timber or rock structures built at right angles to the coast that trap sediment to prevent longshore drift.
   • use natural processes to build up the beach. Increaces tourism and protects the land behind it.
   • starve beaches further along the coast of fresh sediment.
   • unnatural and unatractive to tourists.
   • cost between £5000 to £10,000 each at 200 metre intervals
   • more sustainable and cost effective than other approaches

3. rip rap

   • large rocks that are placed at the foot of a cliff or the top of a beach. forms a permeable barrier to break up the waves but also allow some water to pass through.
   • relatively cheap and easy to construct.
   • easy and cheap to maintain.
   • often they are used for recreation, eg fishing or sunbathing.
   • rocks are usually not locally sourced and look out of place with the local geology.
   • can be dangerous for people climbing over them
   • cost between £100,000 and £300,000 per 100 meters
   • they are sustainable and cheap to maintain and work effectively

4. revetments

   • sloping wooden, concrete or rock structures that are placed at the bottom of a cliff or the top of a beach to break up the waves energy.
   • relativley inexpensive to build
   • they are visually intrusive and unattractve to look at.
   • they need lots of maintenance which will mean that more money will have to be spent on them.
   • can cost up to £4500 per metre.
   • they are not very sustainable as they require regular maintenance.

5. offshore breakwater

   • a partly submerged rock barrier designed to break the waves before they reach the coast.
   • effective permeable barrier.
   • visually unappealing, this could effect tourism rates and the amount of people who want to live there.
   • potential navigation hazard
   • costs between £100,000 and £300,000 per 100 meters
   • effective in its job however is not cost affective.