Hard Engineering - Advantages and Disadvantages

Hard Engineering - Advantages and Disadvantages

1. Rip Rap (Rock Armour)

   • Dissipates wave energy
   • Can make the beach inaccessible for tourists
   • Cost £300 per metre
   • Large rocks placed in front of a cliff
   • Can be cheap, depending on the rock type
   • It is effective for many years
   • Not affective in storm conditions
   • Unatractive
   • One of the ways to prevent, or slow down erosion is to use a hard engineering technique called Rip rap. This is when large rocks are placed in front of a cliff to dissipate the energy of strong waves. This method is effective for many years, and can be very cheap, depending on the rock type. However, this can make the beach inaccessible to tourists, and is not effective in storm conditions.

2. Recurved Sea Wall

   • Walls usually made of concrete. Modern ones, have a curved face
   • Cost £3,000 per linear metre
   • Reflects and absorbs wave energy
   • Very visible - makes residence feel safe
   • Effective for many years
   • Ugly - puts tourists off
   • Can cause waves soaring if not positioned correctly
   • Expensive to build
   • Recurved Sea walls are usually made out of concrete and have a recurved face to reflect and absorb wave energy to stop, or reduce costal erosion. This technique is effective for many years, and makes residence feel safe, as it is very visible, even though it is unattractive and is expensive to build.

3. Groynes

   • Usually made out of wood. Stretches from the coastline to the sea
   • Cost - £5,000 each
   • Prevents LSD - sand builds up on one side of the groyne
   • Keeps beach in place for the tourist industry
   • Effective for many years
   • Unattractive - difficult ti walk along the beach
   • Disrupt the natural processes working on the beach such as LSD
   • Groynes are man made barriers which stretch from the coastline to the sea. This technique prevents Long Sore Drift, as sand builds up on one side of the groyne to keep the beach in place for the tourist industry and is affective for many years. However, groynes are unattractive, making it difficult to walk to walk along the beach and disrupts the natural processes working on the beach, such as LSD

4. Gabions

   • Wire cages filled with stones, used to reduce erosion
   • Cost - £11 per metre
   • Cheaper than other forms of coastal defence
   • Rock cages absorb wave energy
   • Wire cages can break, they need to be securely tied down
   • Not as efficient as other forms of coastal defences
   • Gabions are wire cages filled with stones, used to reduce erosion. Even though the cages can break and are not as efficient as other forms of coastal defence. However, they are cheaper, and the rock cages absorb wave energy

5. Offshore Reef

   • Enormous concrete blocks and natural boulders are sunk offshore to alter wave direction and to dissipate the energy of waves and tides
   • Cost - £1,950 per metre
   • The waves break further offshore and therefore reduce their erosive power
   • They allow the build up of sand due to the reduction in wave energy
   • May be reduced by heavy storms
   • Difficult to install the reefs
   • A way to reduce LSD is to use a hard engineering technique called Offshore Reef. This is when enormous concrete blocks and natural boulders are sunk offshore to alter wave direction and to dissipate the energy of waves and tides. Even though these boulder may be removed by heavy storms and are difficult to install, they allow the build up of sand due to the reduction in wave energy and make waves break further offshore, thus reducing their erosive power