Prevention amd amelioration of floods

Question 1

What are methods of hard engineering and what are the causes?

Answer 1

-dams, levees, wing dykes and straightened channels
-causes unexpected effects elsewhere in drainage basin, eg decreased water quality, increased sedimentation, bed and bank erosion and loss of habitats

Question 2

How does hard existent design reduce flood risks?

Answer 2

temporary: blocking up entrances of houses, sealing doors and windows, removal of damageable goods, use of sandbags
long term: moving living spaces above floodplain, eg stilts

Question 3

What are soft engineering ways of reducing flood peaks?

Answer 3

-reforestation
-reseeding of sparsely vegetated areas to increase evaporative losses
-treatment of slopes such as contour ploughing or terracing to reduce surface runoff
-comprehensive protection of vegetation from wildfires, overgrazing and clear-cutting of forests
-clearance of sediment and other debris form headwater streams
-construction of small water and sediment holding areas
-preservation of nautrual water storage zones, eg lakes