Water Cycle Flashcards
(12 cards)
California drought
Causes:
La Niña bringing drier conditions due to southwest winds from the ocean not delivering water
Climate change = low precipitation and more heatwaves
Over abstraction = 80% used for farming
Increased urban demand
Impacts:
- Peak drought between 2012-2016
- 1000 more wildfires than usual have occurred - 8000 in 2015
- Rainfall of less than 5 inches a year
- Reservoir levels falling below 40% capacity - however, water supplies were really stocked up prior to the drought, easing the situation.
- farmers harvested 640,000 fewer acres
- $2.7bn in agriculture losses in 2015
- 21k agriculture jobs lost
- Gov said 25% water use mandated reduction
- $2bn in economic losses
Sahel drought
Vast semi arid region on the southern edge of the Sahara.
Causes: Human action = feedback loop
- Overcultivation
- Overgrazing
- Population growth
- Deforestation
- frequent civil wars
Casues: Physical
- occupies a transitional climate zone
- the mean annual rainfall (around 85%) is nearly all concentrated in the summer
- Unusually warm sea surface temperatures (SSTs) in tropical seas favour strong convectional uplift = weakens the West African Monsoon and contributes to drought in the Sahel.
Strategies:
- Magic stones = circles which hold water on the soil rather than letting it run over the surface = can improve by up to 50%
- Recycling “grey water”
- The Great Green Wall: African Union project planting trees across 11 countries to slow desert spread.
Keswick and Storm Desmond
Location: Keswick, Lake District, Cumbria.
Rivers: Greta and Derwent.
Causes:
Keswick 2009: 130 mm of rain in 24 hours, saturated ground, and river Greta overflowing.
Storm Desmond 2015: 340 mm of rain in 24 hours, record high river levels, surface runoff, and already saturated ground.
Impacts:
Keswick 2009:
700 homes flooded.
£30 million damage.
Tourism affected.
Storm Desmond 2015:
5,200 homes flooded.
£500 million in damage.
Severe transport disruption and tourism impact.
Responses:
Keswick 2009:
Emergency evacuations, temporary flood barriers, and improved flood defences.
Investment in better flood warning and drainage systems.
Storm Desmond 2015:
Flood warnings issued, emergency services and military involvement.
£500 million recovery fund, new flood defences built.
Evaluation:
Keswick 2009: Short-term recovery effective, but localised vulnerability remained.
Storm Desmond 2015: Flood defences overwhelmed, but long-term defences and climate adaptation now a focus.
The Orgalla Aquifer - USA
Cause: Excessive water extraction for irrigated agriculture = 8 states
450,000km
Irrigates 27% of US farmland
Still, no federal regulation exists for groundwater in much of the US — management is fragmented.
Impacts:
Falling water levels by 100 feet, subsidence, and threats to agriculture and food security
30% depleted by 50 years (6-10x faster than it regenerates)
- Electronic industries store waste solvents in tanks underground (Silicon Valley)
- During inspection authorities found 85% of tanks were leaking
- 60% of the US’s liquid hazardous waste is injected directly into the ground
- waste is injected deep below drinking water sources but has leaked and entered aquifers affecting many states
Response: Adoption of sustainable irrigation techniques, drought-resistant crops, and water recharge methods.
River Wye
River Wye, flows through Wales and England, 215 km long = 5th longest in the UK
Area of Outstanding Natural Beauty (AONB)
Causes:
Agricultural runoff and chicken farming = manure and fertilisers
Up to 70% of phosphate pollution linked to agriculture.
Over 60% of monitored sites on the Wye exceeded safe phosphate levels (Environment Agency, 2022).
Sewage pollution: from septic tanks and wastewater discharge.
Historic industrial pollution: chemicals and heavy metals from past industry.
Impacts:
Eutrophication: algae growth, agal blooms (oxygen depletion), harms fish
Biodiversity loss: decline in aquatic species.
Recreational decline: unsafe for swimming and kayaking.
Health risks: pathogens from animal and human waste.
Responses:
Welsh and UK gov announced £1m joint funding
£2.5bn investment over 5 years from Welsh water
Environment Agency regulations on farming practices
Agri-environment schemes: promote sustainable land management.
Upgraded sewage treatment facilities.
Public awareness campaigns and community clean-ups.
GERD and Nile
Ethiopia, along the Blue Nile downstream of the Tana lake
Roller compacted concrete
2 power stations
$5bn
170m
Began in 2022 generating electricity
11 countries compete
Nile = longest river = 4132 miles
2017 = 300m live by river set to double by 2019
Advantage:
Contains 74bn cubic metres of water
generate up to 2% of Ethiopias annual GDP
can double electricity production = useful for 60m people who have no access to electricity
Disadvantage:
Reduces water supplies to Egypt by 1/3
- alters natural flow of the Nile = affect biodiversity and ecosystems + displaces communities
- Egypt relies on the Nile for 90-97% of its water needs and lose $51bn in agriculture loss
- The UN has said Egypt could run out of water by 2025
Laws/agreements:
1929 = Agreement between UK and Egypt granted rights to river/anonymity over development (Sudan was UK colony)
1959 = Egypt and Sudan sign agreement increasing allocations of water in both areas
2006 = A Nile River Basin Commission was established to ensure equal and fair usage of the River Nile
2011 = Egypt conetsted the GERD
2015 = Egypt, Ethiopia, Sudan signed agreement over dam
Mekong river
Flows through 6 countries: China, Myanmar, Laos, Thailand, Cambodia, Vietnam.
4,350 km long
Causes of Conflict:
Upstream dams by China (11 dams) and Laos reduce flow downstream (Vietnam and Cambodia)
competing interests = Hydropower development benefits upstream countries, but harms downstream ones - fishing and farming
Climate change worsens water scarcity and variability
Impacts:
Environmental:
Fish populations decline in Cambodia’s Tonle Sap Lake.
Loss of sediment and wetland habitats.
Social & Economic:
Food insecurity and falling incomes in Vietnam and Cambodia.
Saltwater intrusion threatens farming in the Mekong Delta (home to 17 million)
Tension between upstream (China and Laos) and downstream (Vietnam)
Management:
Mekong River Commission (MRC) formed in 1995 by Laos, Thailand, Cambodia, and Vietnam = aims to coordinate water use, but China is not a full member and decisions are non-binding.
Lancang–Mekong Cooperation (2016) – includes all 6 countries, led by China.
China’s south-north water transfer
One of the largest water transfer projects in the world
Planning began in 1952, with work starting in 2002, and is expected to be completed by 2050
Cost $62bn = involves resettlement of people
It aims to divert 45bnm³ of water a year from surplus river = south and east, to the north where there is frequent water deficits in places such as Beijing and Tianjin
The 3 main diverting routes:
Western route - started in 2010, through high-altitude terrain
Passes high industrial activity so fears that water will become polluted on transfer and reduce the volumes in the Yangtze
Central route - this is a 1267km diversion with some of the water from the Three Gorges Dam being used in order help
Eastern route - this route is 1,155km long diversion from the Yangtze river next to Shanghai to Beijing and Tianjin in the north
Stakeholders:
- Government sponsored ‘South to North’ Water Transfer Project Company
- Corporate civil engineering companies building 3 major canals, pipelines, tunnels and pumping stations
Singapore
- little natural water resources
- made water management one of its priorities for its 6 million residents
Based on 3 key ideas:
Collect all water - since 2003, domestic water consumption has fallen by 24 litres per person per day
Re-use water - Singapore has cutting edge technology to re-use its grey-water called NEWater = requires stringent purification and treatment using advanced dual-membrane (micro filtration and reverse osmosis) and ultraviolet technologies.
Desalinate - Singapore now has 5 desalination plants meeting up to 25% of demand
IWRM = Integrated Water Resources Management
It aims to treat a river basin holistically to ensure 3 things:
Water is used to maximum efficiency
Equitable distribution
Conserve the environmental quality of rivers and its catchments
IWRM is successful at a local, community level, but not at national or international levels
Water Frameworks
UN Economic Commission for Europe (UNECE) - the convention promotes joint management and conservation of all shared freshwater ecosystems
Helsinki (1966) and Berlin (2004) Rules - ensure that all have an ‘equitable use’ and ‘equitable shares’ concept
The Water Convention and the Protocol on Water and Health - jointly serviced by UNECE and WHO-Europe, it is a unique legally binding framework that aims to protect human health through improved water management and reduction of water-related diseases.
The Protocol provides a practical advice on how to provide the human rights to water and sanitation
With the increasing risks of climate change, there is the potential for water wars to be global, despite the degrees of international cooperation at present
Proper management of current water supplies are crucial and binding international agreements need to be in place for a sustainable water supply for future generations
Flooding in Bangladesh
Chittagong in Bangladesh is the second largest city in Bangladesh
It has a population of almost 8.5 million people
The flood hazard is classified as high
Flooding threat can be increased by downwarping = occur due to the accretion (build up) of sediment brought down by rivers that create the deltas such as in
Bangladesh
In July 2012, high tidal water affected over 10% of the sub districts and 15 districts
The flood affected 1.3 million people
People, in some areas, are now used to their homes and businesses being flooded twice a day by high tides
Some estimates suggest the area may experience a sea level rise of 30cm over the next 20 years
In 2019, the government approved a flood control project including:
- A 2.7km retaining wall
- An 19km flood wall
- 69 pumps
- Improved drainage
This may cause conflict because, there will be winners and losers:
- People may be required to leave their homes
- Businesses will be more protected
