2.1.5 - deficity within the water cycle

What does the term water balance mean

The balance between precipitation, evapotranspiration and runoff

What is soil moisture recharge

When the ground water store has run out and fills up through precipitation

What is soil moisture utilisation

When there is les precipitation so the ground water is used by plants

What is soil moisture deficit

There is less soil moisture than we need

What is soil moisture surplus

When there is more soil moisture than we need

What does meteorological mean

To do with the weather

What are the 4 types of drought

• meteorological

• Hydrological

• Agricultural

What is a meteorological drought

Reasons to do with the weather that results in a drought e.g.

• natural variations in atmosphere conditions

• El Niño events

• Climate change

• Less precipitation

What is an agricultural drought

When there isn’t enough water for the average crop production of a place

What is a hydrological drought

When there isn’t enough water for a place e.g. domestic and agricultural water

How does deforestation contribute to a hydrological drought

Evapotranspiration decreases which means there will be less condensation and therefore less rainfall

What are features of a society vulnerable to drought

• Lack of drought management policies

• Extended period of low precipitation

• Poverty

• Over dependence on one natural resource

What are some features of a society resilient to drought

• drought management policies implemented

• More than one natural resource

• Authorities are held accountable

What happened in the 2023 drought in Pakistan

• temps over 50 Celsius

• No rain for a year

• Dry season came a month early

• Groundwater store is salty and can’t be used

• Pipeline project hadn’t been finished yet

When was the drought in Pakistan

2023

When was the drought in the uk

1976

What were some of the human effects of the drought in England

• domestic supplies fell

• Water rationing - it could only be used for a few hours

• Agricultural problems

• Food prices rise

How high did temperatures reach in some parts of the uk

32

How long did the temperatures last for in the uk

15 days

How many days did some parts of SW England have no rain for

45 days

What % of rainfall did southern parts of England get over 15 months

60

How many months had been dry before the uk drought

9 months

What is an aquifer

It’s a permeable rock layer that contains water that can be extracted for human use

What are some human causes for a decrease in aquifer stores

• population change - more people need more water

• Agricultural demand - more crops are needed as there’s more people

How are aquifers naturally recharged

Through percolating rain water

How can aquifers be artificially recharged

• damns adjacent to rivers to cause a flood and then percolation

• Recharging basin can be made to gather the water so it can percolate

How big is the central London aquifer

30km wide by 40km long

How far below the surface is the CLA

60m

How many people get their water from the CLA

2 million

How was the CLA poorly managed

In the 19th-20th century due to increasing population and industrial demand it meant that the groundwater levels fell to dangerous levels

How do we manage groundwater and aquifers

Through the Gardit strategy - it has helped to manage abstraction since 1992 to ensure groundwater levels stay stable

What does GARDIT stand for

General aquifer research development and investigation team

What is abstraction

Either temporarily or permanently removing water from a natural resource

What methods are used to manage groundwater levels

They vary depending on water levels and weather conditions e.g. when water levels are higher abstraction can be increased

How much have ground water levels risen since 2000

From 8m-15m

What is water confidence

For most months of the year there is more rain than we need

What is water concern

When for most months in the year there is less water than we need

How big is the area covered by Thames water

180km