Case Studies To Learn

Question 1

What happens to the 2/3 of the rainfall that doesn’t reach the Atlantic Ocean

Answer 1

Evaporated
Intercepted
Falls again as rainfall

Question 2

What type of rainfall falls in the rainforest

Answer 2

Conventional rainfall

Question 3

What is suggested about the rate of regional rainfall

Answer 3

Reduce by up to 20%
According to leeds university

Question 4

Give a place example to illustrate the impact of deforestation on the water cycle.

Answer 4

In Rondônia, one of the most heavily deforested areas of Brazil, data shows an 18-day delay in the rainy season compared to the 1970s.

Question 5

What has happened to the amount of carbon trees have taken in

Answer 5

In 2015 trees took in 50% less carbon than in 1990s

Question 6

How much less carbon does pasture land store and why

Answer 6

9x less
Lack of decomposers from low rates of nutrients in soil

Question 7

Positive feedback cycle- drought

Answer 7

Drought -> trees lose leaves -> less evaporation -> increased drought

Question 8

Positive feedback increased warming

Answer 8

Increased warming -> more wildfires -> increased atmospheric Aerosols -> decrease in droplet size -> less precipitation -> increased warming

Question 9

What happened to the deforestation rate in 2021/2022?

Answer 9

Slowed by 75%

Question 10

What is a positive of the protected areas of the rainforest?

Answer 10

They produced 10x less emissions

Question 11

Water balance equation for river exe

Answer 11

Precipitation (1295) = evaporation +/- storage (451mm) + runoff (844mm)

Question 12

Underlying bedrock river exe

Answer 12

Devonian sandstone - impermeable
Makes up 85% of underlying bedrock
Little percolation
Increased runoff

Question 13

What is a river regime

Answer 13

Pattern of a rivers discharge over the course of a year

Question 14

Physical features of river exe catchment that increase flashiness of the hydrograph

Answer 14

Geology - 85% rock is impermeable Devonian sandstone
Lots of tributaries
Steep slopes
Little vegetation - 67% grassland.

Question 15

Identify a human feature on the Exe and explain how it makes the river is less flashy than expected.

Answer 15

The Wimbleball Reservoir (built in 1979) on the River Haddeo, an upland tributary of the Exe, regulates water flow, ensuring a steady regime throughout the year. It prevents peaks and troughs that might cause flooding or drought and is a significant water store.

Question 16

Outline what is being done to reverse damage done to the River Exe catchment in the past and to further reduce flood risk.

Answer 16

• Areas of peat moorland are being restored by the Exmoor Mires Partnership.
• Over the past two decades hundreds of kilometres of old ditches have been blocked to increase water storage on the moorlands and create wetter, healthier peatland.

Question 17

Evaluate the impact of the peatland restoration project on reducing flood risk downstream.

Answer 17

Positive:
• Water storage on the moorland has increased – in some areas the
water table has risen by 2.65cm and there has been a 33% reduction in storm flow leaving restored sites. Examination of the hydrograph shows a clear increase in base flow.
Limitations:
• The relatively small scale of the project limits its potential impact
although it could be extended in the future if landowners agree.
• In the future, more intense storms, linked to climate change, may
counteract any recent gains made.

Question 18

Outline the role played by the peatland in the upper catchment of the Exe in the local carbon cycle.

Answer 18

The moorland on Exmoor has large amounts of peat which is a major natural carbon sink. It is made up of dead organic matter, including sphagnum moss, which is compacted in saturated conditions reducing decomposition.

Question 19

Outline the changes in the carbon cycle caused by the digging of drainage ditches in the past.

Answer 19

The ditches caused the peat to dry out making it more susceptible to erosion. Carbon in the peat dissolved in water and was transported downstream affecting water quality as it made the water brown. The loss of carbon has the potential to turn the moorland peat from a sink to a source.

Question 20

Evaluate the impact of the peatland restoration project on the carbon cycle and water quality.

Answer 20

Blocking ditches results in wetter, healthier peatland which increased carbon storage as less is dissolved in water running off into ditches, which improves water quality. Early results show an overall reduction of carbon leaving the restored sites of up to 50%, however data over a longer timescale is needed to get a fuller picture.