Why are some river basins naturally vulnerable to flooding

Question 1

geology

Answer 1

porous rocks e.g. chalk and sandstone act as underground reservoirs, storing water sand releasing it slowly through groundwater flow to rivers e.g. river avon. non poros rocks lack storage capacity e.g. shale=rapid runoff

Question 2

slopes

Answer 2

steep slope are typical in upland catchments. rain falling on steep gradients will quickly run off into river shore response times and high peak flows e.g. river kent

Question 3

vegetation

Answer 3

in well vegetated catchment areas interception is high=slow movement of water to rivers and increases evaporation. extends lag time and reduces peak flows

Question 4

drainage density

Answer 4

average length of stream channel per km(2) the greater the density, the shorter the distance water has to travel overland to reach the stream

Question 5

precipitation type

Answer 5

hilly/mountainous areas may support snow cover in winter. melting in spring leads to seasonal flooding e.g. Colorado river USA