hard engineering

• Outline what hard engineering is in terms of flood management.

  Hard engineering involves the use of man-made structures to control the flow of a river and prevent flooding. They are an expensive, but effective flood management option.
• Describe how dams & reservoirs work.

  Dams are walls built across rivers to trap water, forming an artificial lake, or reservoir.
• Describe the advantages of dams & reservoirs.

  Reservoirs store and regulate the flow of water. They can be used as a source of drinking water and to generate hydroelectric power.
• Describe the disadvantages of dams & reservoirs.

  Dams are very expensive and can flood large areas of land, damaging habitats and displacing many people. They can also prevent the transportation of eroded material, reducing the fertility of farmland downstream.
• Describe how river straightening works.

  River straightening involves cutting out meanders to create straighter, wider and deeper river channels.
• Describe the advantages of river straightening.

  Because of less friction and the shortened river length, water flows out of an area more quickly, reducing the risk of flooding in that area.
• Describe the disadvantages of river straightening.

  Flooding is more likely to occur downstream as water is carried there more quickly and the fast-flowing water causes greater erosion.
• Describe how embankments work.

  Embankments are artificially raised banks built alongside rivers.
• Describe the advantages of embankments.

  The raised banks enable rivers to hold more water, protecting surrounding towns and cities.
• Describe the disadvantages of embankments.

  Embankments are expensive and can be unsightly. Devastating floods can result if an embankment fails or if the water level rises about the level of the banking.
• Describe how flood relief channels work.

  Flood relief channels are used to divert water away from urban areas or to redirect water if the river level becomes too high.
• Describe the advantages of flood relief channels.

  Urban areas are at less risk from flooding because water is diverted away.
• Describe the disadvantages of flood relief channels.

  Flood relief channels are costly, and should river discharge increase significantly, they could overflow and cause severe flooding.