Water key facts and case studies

How much of the Earth’s surface does water cover?

71%

What % of water is undrinkable saltwater?

96.5%+

What % of freshwater is in ice caps and glaciers?

70%

What % of freshwater is in groundwater?

29%

Reservoir turnover time of oceans

3,600 years

Reservoir turnover time of ice caps

15,000 years

Reservoir turnover time of rivers and lakes

2 weeks to 10 years

How much of the hydrological cycle is the ocean?

>90%

How many days a year does it rain for in the UK on average?

156.2

Average UK annual rainfall

1,154mm

Mississippi drainage basin

World’s 3rd largest watershed

Drainage basin for 41% of the USA

Fossil water in the Sahara

• Extends across an area double the size of mainland France

• Holds more than 30,000km² water

• Water has accumulated over the last 1,000,000 years

• Supports Tunisia, Algeria, Libya etc

• Estimated recharge is 40% of withdrawals

Amazon river regime

• 6,308km long and has a drainage basin of 6 million km²

• Major influences are rainforest climate, seasonal precipitation and high EVT

• Peak discharge in April, May and the lowest discharge is September

• Linked to wet and dry seasons and snowmelt from the Andes

• Human influences - large dams for cities and HEP

Yukon river regime

• 3,540km long and drainage basin of 850,000km²

• Tundra climate and flows through a mountain range

• Peak discharge May, June with a dramatic increase due to snowmelt

• Low from December to May due to frozen precipitation - very large seasonal variability

• Few human influences but a little HEP

Nile river regime

• Regime changed significantly by the construction of the Aswan Dam in 1970

• River flow reduced by 65% and became regulated between seasons so flood peaks in September were greatly reduced

Austwick Beck

• Flashy hydrograph - short lag time with a high peak discharge - flash flood

• Shale rock - less permeable

• Many tributaries mean at Austwick - high drainage basin

• Circular drainage basin

• Small amount of woodland - less interception

Clapham Beck

• Subdued hydrograph

• No tributaries

• Elongated drainage basin

• Large woodland around the stream just before Clapham - interception, absorption, slows down

• Gritstone and sandstone and limestone - more permeable

• Artificial lake - more surface storage

What % of the Amazon has been deforested?

20% in the last 50 years

How much intercepted water in a forest is returned to the atmosphere by EVT?

75% which is reduced to 25% when forest is cleared

By how much has the volume of the Aral Sea shrunk by?

80%

What % of global food production depends on the depletion of groundwater?

10%

How many people in the lower Mekong river basin depend on agriculture for their livelihood?

65 million+

Which areas of the UK are very vulnerable in extreme weather?

York, Manchester, Leeds due to dense populations and a high, quick peak discharge

Area of Amazon drainage basin

6.1 million km²

Largest drainage basin in the world

What countries is the Amazon located in?

7: Brazil, Bolivia, Peru, Colombia, Ecuador, Venezuela, Guyana

What % of fresh water entering the oceans each day comes from the Amazon?

15%

Treaty for Amazonian Cooperation

• Example of an agreement between countries to protect the Amazon

• Signed by the 7 drainage basin countries and Suriname

• Emphasise the need to improve the QoL of Amazonian people and preserve the natural environment as economic development takes place

Role of the Amazon basin for global hydrology

Acts as a vapour sink for moisture coming in from the Atlantic - humid air produces precipitation and convective clouds

By how much is deforestation delaying the onset of the rainy season in a region of the Amazon?

6 days per decade

Soil infiltration rates

Sandy - 3-12 mm/hr

Less permeable clay - 0-4 mm/hr

Vegetation infiltration rates

Forests - 50 mm/hr

Pasture 13-23 mm/hr

Economic loss of 1992 El Nino

$290 million on the Pacific coast of South America in fisheries

What % of all health facilities in Peru were damaged in the 1997 El Nino?

10%

Economic impact of the 1982 El Nino in Eastern Australia

$2000 million loss in agricultural production

After how many years does deforested soil become infertile?

5 to 8 years

Amazon dam building

• Manaus

• HEP - Baseload compliancy helps industry

• Reduces natural variability in the river regime

• No flooding

• Destroys wetlands

2024 January Nottingham flooding

80% of average January rainfall fell in 4 days

Specific drough definition

3+ months with less than 50% of average rain

What % of the planet has drought exposure?

38%

This land area has 70% of the global population

When was the strongest ever El Nino?

1997

1998 was the strongest ever La Nina

What % of Earth’s surface do wetlands cover?

10%

Human contributors to and impacts of desertification in the Sahel

• Poverty and civil war drove people onto marginal land

• Increased rural population increased pressure for food

• Acts as a positive feedback loop enhancing impacts of drought

• Obstructions to pastoral migration and encroachment of farmlands on grazing areas impacted the socio-economic conditions of nomadic communities

• Development of cotton growing on farms reduced grazing areas

• 1999/2000 Ethiopia and Eritrean famine/drought

How many people needed assistance for food in the 1999/2000 Ethiopian/Eritrean famine?

10 million

What % of water falls in the summer in the Sahel?

85%

Australia Big Dry

• 2006

• Affected more than 50% farmlands, including an area that provides 50% of agriculture

• River Murray had been overextracted

• High per capita consumption of water

• Many farms rely on irrigation

• Low, highly variable rain

• Droughts vary massively

• Many droughts link to El Nino

• Since 1970s, the East has become drier

How much of Australia is affected by drought in any given year?

30%

Human factors contributing to 2022 Pakistan flood risk

• Anthropogenic climate change

• Lack of resources for aid organisations

• Not enough medical camps

• Government slow to act

Human factors contributing to 2010 Pakistan floods

• Nearly 70% of Pakistan’s population worked in the agricultural sector and so lived close to the rivers for irrigation

• Rural communities flooded so people lost homes and livelihoods

• Urban population poorer than rural so Karachi was highly affected as water pooled and could not freely flow

• Poverty reduced people’s ability to evacuate

• 2010 floods surpassed any preventative measures which meant these measures were weakened already before floods in 2011

• Deforestation and illegal logging

Social and economic impacts of 2022 Pakistan floods

• Affected 33 million people

• More than 1,700 died

• 28,000 schools and health clinics damaged

• Economic loss of $30bn

• 4 million hectares of agricultural land damaged

• 800,000 cattle and livestock died

• 40% of children in affected areas had stunted growth

• 25% of children in affected areas were underweight

• Malaria, dengue fever, diarrhoea

Social and economic impacts of 2010 Pakistan floods

• More than 20 million people affected

• 1.2 million homes damaged

• 1,600 deaths

• 11,000 schools closed

• Losses of $1bn+ in the agricultural sector

• 3.6 million hectares of agricultural land destroyed

Causes of 2007 UK flooding

• Rain in June and July was 20% higher than ever seen before

• On 25th June, the month’s rainfall fell in 1 day

• Jet stream did not move as normal (La Nina) so bad weather stayed over Britain

Causes of 2015 flooding

December 2015 was the wettest month and second wettest winter since 1910 in the UK

Record maximum peak flows in North England

Socioeconomic impacts of the 2007 flooding

• Estimated £3bn of flood damage covered by insurance and £3bn not covered by insurance

• 500,000 homes affected nationwide

• In Hull, 10,000 homes were damaged

• 340,000 people left without running water for a week in Gloucestershire

• Cost of repairing roads in Gloucestershire was £25 million

Socioeconomic impacts of 2015 flooding

• 5,200 homes across Cumbria and Lancashire flooded

• 43,000 homes in North-East England had no power

• 2 people killed

• £500m damage across Cumbria

• 1,000 evacuated in Cumbria

• 40 schools in Cumbria closed

What % of rising sea levels is ice melt and thermal expansion?

Ice melt - 40%

Thermal expansion - 60%

Major water-related events 2022 examples

• China - heatwave led to flash floods and low levels in the Yangtze

• Australia - high rainfall caused flood events

• Brazil - Intense rainfall, causing flash floods and landslides

• Europe - hot summer led to flash droughts and low river levels

How much more water does warm air store?

7% per degree C of warming

How many is La Ninas in a row by 2022?

2022 was the third La Nina in a row

What % of the water cycle happens over the ocean?

90%

What % of the severity of Western USA and North Mexico droughts is due to global warming?

46%

When did most global temperature and climate records begin?

1700s and 1800s

What % of wetlands have been lost?

85%

How many people live in water stress?

733 million+

What % of countries have trans-boundary water agreements?

25% e.g. Nile

Global freshwater usage

22% industrial

6% household

2% drinking water

70% agricultural

Places with water availability issues

Mexico - pesticides and fertilisers

Arizona - irrigation increases salinity

Bangladesh - aquifers overdrawn

Mexico City - ground subsidence

Pakistan - excessive pumping, wells drying out

NE China - industrial pollution

California - saltwater incursion

How many illegal wells in Pakistan and India?

3 million

• Leading to a falling water table

Why does Japan use a lot of water?

Developing high tech products e.g. laptops

Cost of water variations

50L costs 0.1% of typical daily salary in the UK

50L costs 108% of typical daily salary in Cambodia

50L costs 45% of typical daily salary in India

What % of its available blue water supplies does Saudi Arabia use?

104%

What % of Egypt’s population live within 1 mile of the Nile?

80%

How many people had to move to allow the construction of the Three Gorges Dam?

1.3 million

How many people use contaminated water daily in China?

300 million

What % of major lakes and coastal zones in China are highly polluted?

75% major lakes

25% coastal zones

Chinese cancer cluster villages

Liver + digestive cancers cause up to 80% of deaths - water pollution

How many people worldwide have some signs of arsenic poisoning from drinking water?

137 million in 70 countries

What % of tube wells in Bangladesh are unsafe due to arsenic poisoning?

20%

How much water do we each need to meet basic human needs?

1000m³ per year

This can be met by 60% of global accessible freshwater supplies

How much of the global population will be water vulnerable by 2025?

50%

What % of the world’s water supplies is in 10 countries?

60%

What % of the world’s population live in areas receiving 25% of annual rainfall?

66%

How many people will be experiencing water stress by 2050?

4 billion

How much water does the average Californian use per day?

181 gallons

More water than any other US state - US average is 80-100 gallons

California water usage

60.7% irrigation

16.6% public supply

1.0% industrial

How wide is the coastal zone in which most of California’s water falls?

250km wide

How much water does South and Far-East California receive?

Under 100mm rainfall due to the rain shadow of the Sierra Nevada mountains

How much of the annual rainfall in California falls between November and March?

3.5% - seasonal shortages

California population growth

2 million in 1900s to 39.54 million in 2020

Spatial imbalance of water in California

75% of demand from south of Sacramento but 75% of rainfall in the North

Losses to the agricultural sector because of severe drought in California in 2021

Sector decreased by $1.2 billion and lost 8700 farm jobs

How many acres of farmland in California may need to be taken out of cultivation by 2040?

0.5 million acres in order to stabilise aquifers

Which species of salmon have been impacted by overextraction of the Shasta and Scott rivers?

Chinook and Coho

Solutions for California’s water shortages

• Individuals and companies reduce their water use

• More efficient irrigation methods

• Irrigate less land e.g. gardens, golf courses, parks

• Recycling wasterwater

• Storm water capture

• Desalination

• Changes to water rights and usage laws

How many people live without access to clean water?

1 billion

How many people live without sanitation?

2.5 billion

New York water cost

80 cents per 1000L

Baranquilla water cost

$5.6 per 1000L

• Lack of infrastructure

When was water privatised in the UK?

• 70s and 80s

• Due to the neo-liberal view popularised by Thatcher

• Water would be best managed by private companies as there would be a profit motive for efficiency, investment and conservation

Role of World Bank and the IMF in water privatisation

• Structural Adjustment Programmes to help developing countries overcome debt

• Part of this included the privatisation of utilities including water

• TNCs from western powers often take over these utilities - fair?

Cochabamba privatisation (Bolivia)

• In 1999 water supply was privatised but in 2000 this was undone

• Prior to the privatisation, only 57% of the population was covered by gov. water

• There was 50% leakage, rationing and a lack of investment

• Dependency on private wells, vendors and carriers

• The privatisation increased water price by 35% but the service quality didn’t improve

• There were riots, protests and violence in response - 12+ people died

• 80,000 people occupied the main square

• The privatisation gave the water company a monopoly over all water infrastructure, including the informal supplies