Rivers KQ3

Question 0

Name the outputs of the Hydrological Cycle?

Answer 0

Evaporation

Transpiration

Question 1

Name the inputs of the Hydrological Cycle?

Answer 1

Precipitation

Infiltration and Percolation in soil

Question 2

Name the processes of the Hydrological Cycle?

Answer 2

Channel flow

Sublimation and melting of glaciers

Question 3

What are quick flow processes?

Answer 3

The flow of water through porous soils,surface run off that reach rivers very quickly.

Question 4

What are slowflow processes or base flow?

Answer 4

The flow of water through rocks so it can take weeks for the ground water to reach the river.

Question 5

What is the interflow?

Answer 5

Water that flows at an intermediate speed through through flow.

Question 6

What is discharge measured by?

Answer 6

Cubic metres per second / cumecs

Question 7

What is bank full discharge?

Answer 7

The full amount of water a river channel can hold.

Question 8

What is the flood discharge?

Answer 8

The area above bankfull discharge where the water will spill onto the flood plain.

Question 9

What is a storm hydrograph?

Answer 9

It shows the short term response to a particular rainfall event.

Question 10

What are the features of a storm hydrograph?

Answer 10

Rainfall - time of peak rainfall is indicated.
Highest discharge - peak flow
Time difference between peak rainfall and highest discharge = lag time
Gradual increase in discharge indicated by the rising limb
Decrease in discharge indicated by the falling limb
Relative contribution of quickflow and base flow processes
The bankfull discharge and flood discharge

Question 11

What causes flooding?

Answer 11

Excessive precipitation over long period / intensive precipitation over short period / snow melt / climatic hazards like hurricanes = cannot be managed
Nature of drainage basin / relief / rock and soil type / natural vegetation = can be managed

Question 12

Factors of a flashy hydrograph?

Answer 12

Short lived and intense precipitation
Impermeable rocks
Steep relief
Urban area - channeled through water into drains then a stream 
Small or round drainage basin

ALL REDUCE LAG TIME

Question 13

Case study for river environments?

Answer 13

July 2007 Floods
Natural causes - 140mm rain in June double the average and July also had higher than average rainfall = soils became saturated and river levels rose- majority of flooding happened in Tewksbury
Impacts - people lost their businesses and many houses were extensively flooded
Management - Environment agency worked with DEFRA and managed the town and flood risk for Tewksbury and Gloucestershire.

Question 14

What were the short term impacts of the 2007 floods?

Answer 14

Up to 1 month….
People had to leave their homes
Disruption to electricity and water supplies - 50,000 without power, 140,000 without water for 5 days
Mammals were also drowned

Question 15

What were the medium term impacts of the 2007 floods?

Answer 15

Up to 1 year …

Very expensive as some people were still not able to live at their homes.

Question 16

What were the long term impacts of the 2007 floods?

Answer 16

More than 1 year…
£1-1.5 million in insurance losses
Many crops were submerged and ruined
But the deposited clay from the flood has increased the fertility of the soil

Question 17

What makes some basins naturally more vulnerable.

Answer 17

Geology - porous or impermeable rodks
Soil type - soil permeability
Steep slopes
Low levels of vegetation - high levels slow down the movement
Greater density of drainage - shorter distance = decrease lag time

Question 18

Why is Shrewsbury vulnerable to flooding?

Answer 18

Steep sided valleys - more run off
Many tributaries meet here
Impermeable rock

Question 19

What is the difference between fluvial and pluvial flooding?

Answer 19

Pluvial = the stores of water become too full and impermeability causes flooding
Fluvial = the river simply overflows