river flooding pg

Question 1

what is river flooding

Answer 1

when the volume of water exceeds the capacity of the river channel and therefore overflows the river banks

Question 2

what causes river to flood h and p

Answer 2

human
as a result of us altering the db of a river itself

physical
result of natural enviroment

Question 3

name physical and human causes of flooding

Answer 3

physical
relief, rainfall, rock type, basin size, soil saturation, vegetation

human
deforestation, basin size, urbanisation

Question 4

urbanisation description

Answer 4

building in areas at risk of flooding - tarmac areas made so water cannot drain and flows into river

Question 5

agriculture des

Answer 5

arable farming - soil left unused and exposed for periods of time leads to more surface runoff

Question 6

deforestation des

Answer 6

trees absorb water so if cut down less water is absorbed and will end up in river

Question 7

rock type des

Answer 7

impermeable rocks don’t allow water to pass through so river more likely to flood because water doesn’t rain but held in river

Question 8

basin size des

Answer 8

when large able to store more water. if small increased risk of flooding as water capacity is lower

Question 9

soil saturation des

Answer 9

when soil no longer absorb any more water it becomes saturated and causes flow of water over land into river

Question 10

relief des

Answer 10

steep slopes allow water run over land quickly leaving little time for water to seep into soil so water enters nearby river

Question 11

precipitation des

Answer 11

rainstorms can lead to flash floods as river cannot contain increased volume of water

Question 12

what is discharge measured in?

Answer 12

cumecs meters per sec

Question 13

what is a flood hydrograph

Answer 13

graph that plots river discharge after storm.

Question 14

peak discharge def

Answer 14

highest discharge recorded

Question 15

lag time def

Answer 15

difference between peak discharge and peak rainfall

Question 16

hard engineering def

Answer 16

strong construction methods to hold back floodwater usually expensive needs maintaining

Question 17

examples of hard engineering (6)

Answer 17

channel enlargement by dredging 
embankment
concrete lined channel
reservoir (caused by dam)
afforestation
land use zoning

Question 18

what is soft engineering

Answer 18

more natural ways to reduce impact of flooding on humans with less intervention and more preparation usually sustainable

Question 19

methods of soft engineering

Answer 19

afforestation (planting trees)

floodplain zoning

Question 20

what are names of warning levels for flooding and defs

Answer 20

severe flood warning
extreme danger to life and property. stay in upper floors and turn off electricity and leave when possible

flood watch
flooding on low lying land and roads.

flood warning
threat to homes and businesses should move items to upper floors turn off electricity