Q.1
How do impermeable rocks influence the risk of flooding?
  • Impermeable rocks increase the flood risk
  • Impermeable rocks decrease the flood risk
  • Impermeable rocks don’t influence flood risk, but they do force rivers to rise faster
  • Impermeable rocks are never associated with rivers
Q.2
Once raised the Thames Barrier stops water movement along the river. How do barriers such as this reduce the risk of flooding?
  • The barrier prevents the high tide increasing the water level in the river
  • The barrier holds back the outflowing river discharge
  • The barrier prevents groundwater entering the river
  • The barrier stops tributaries entering the main channel
Q.3
In 1993 the Mississippi river overtopped its banks and flooded a huge proportion of the USA. How did hard engineering lead to this catastrophic flooding?
  • Dams were built to hold back the water levels. Due to the soft geology on either side these failed. The extra pressure of the water from upstream dam failures contributed to failures further down stream
  • Levees had been constructed to raise the banks, as the river bed silted these were raised and the river flowed higher than the surrounding land. When they failed the water drained across the land
  • Straightening of the rivers lowered the bed level, meaning the channel was able to hold more water. The extra water created a greater flood when the banks burst
  • The width of the river valley was increased, allowing more water to build up in the valley before the banks burst and the river flooded the area
Q.4
In Ancient Egypt they welcomed the floods each year with ceremonies and celebration. How are floods beneficial to the land either side of the river?
  • The flood destroys predators of domestic animals
  • The silt deposited by the flood can make the ground more fertile
  • The flood removes debris from the land
  • The flood drops stones and blocks on to the land which are used as building materials
Q.5
Which of the following river features are influenced or created by flooding?
  • Waterfalls
  • Levees
  • Ox-Bow Lakes
  • Flood plains
Q.6
Each year the Amazon River and several tributaries over top their banks and flood the surrounding area. Which of the following is a positive of these seasonal floods?
  • The floods deposit alluvial silt on the thin infertile soils of the rainforest floor
  • The flooded areas provide a unique habitat for certain species of fish during the flood season
  • Increased pollution levels in the river may lead to an increase of pollution in the flooded soils
  • Seasonal pools either side of the river are flooded and the water refreshed after the drier periods
Q.7
Deforestation can increase the risk of flooding. Which of these is a way trees, vegetation and forests decrease the chances of flooding?
  • The uptake and storage of water into the leaves and stems of plants removes it from the ground
  • Less water gets to the river as transpiration via the leaves means water is returned to the atmosphere
  • Water falls on the trees and so does not reach the ground
  • River banks are made more stable by vegetation
Q.8
How do river floods occur?
  • When the volume of water in the river is more than the channel can contain
  • When it rains heavily, increasing the amount of water in the river channel
  • When dams release water, giving a sudden large amount of water in the river channel
  • During spring melt, leading to a large amount of water suddenly entering the channel
Q.9
Rather than putting expensive flood defenses in place, why are some areas being abandoned to flooding?
  • The areas abandoned are industrial areas, reducing the economic cost and risk to residential areas
  • Council planning and zoning means that it is illegal to build on the floodplain. Older properties that ave already been built on the flood plain do not represent a cost-effective area to protect
  • Allowing rivers to flood is cheaper in the short term, but may be more expensive in the long term as it encourages flooding down river over time
  • Allowing rivers to naturally flood areas that are undeveloped reduces the risks of flooding further down river. The cost of protecting the entire length of every river would be prohibitively expensive
Q.10
In Britain millions of homes are required to keep up with housing needs. How does building houses increase the risk of flooding?
  • Increased water consumption increases the amount of necessary drainage
  • More lawns, trees and other vegetation leads to more water soaking into the ground after people water their plants
  • Increased pollution leads to more rain in the immediate area
  • Impermeable surfaces, better drainage and less vegetation all lead to water reaching the river channels faster
0 h : 0 m : 1 s