The Water Cycle
The Water Cycle is the process by which water is recycled and transported from the Earth’s surface to the atmosphere by evaporation and back to the surface again through rainfall, indeed there is as much water on Earth now as there was when the Dinosaurs were alive.
However, mankind has an influence on the way in which water is used and stored, and as such we need to be able to control it. The BBC have information and interactive resources on the water cycle and some Key Stage 1 & 2 resources are available from the DfES
Trends in water use
Nationally and globally, water consumption is rising rapidly. The last few summers have involved high profile water shortages and hosepipe bans across the southern counties of England.
UK households currently consume an average of 150 litres per person per day, this together with extensive house building programmes often in drought risk areas means that demand is outstripping supply in some regions of the country.
Environmental Issues of Water Use
Water is an infinite resource because the same amount is in existence in the world (around 1.4 billion km3). But changes in rainfall patterns can wreak havoc, causing extensive flooding or drought to areas not well equipped to deal with the change.
Flooding can cause severe soil erosion and destroy habitats but it can also be a vital source of nutrients for soils that would otherwise need man made intervention to keep them fertile. Flooding may be exacerbated by changes in land use such as building on floodplains using non porous materials such as concrete and tarmac and changes in agricultural practices such as the filling in of dykes (trenches found at the edge of fields) to allow two fields to be merged into one.
Droughts can devastate wildlife, agricultural and human populations and can cause soil erosion as the dry soils are blown away. Rainfall is also a powerful ‘cleanser’ removing low level air pollutants (from man made sources) that can affect the health of plants, animals and humans that come into contact with it. Drought can therefore cause air pollutant concentrations to rise above safe thresholds, increasing the health risks.
Human water use requires energy for pumping the water to where it is needed and for the treatment processes that make it safe for us to use and to dispose of. For every 1000 litres (1m3) of water used; 0.4 kilogram’s of carbon dioxide are released into the atmosphere and all the environmental issues associated with energy use are also relevant when we talk about water.
However, our energy use may have a devastating affect on water availability. Changing rainfall patterns and melting polar ice caps could change the course of rivers or stop them flowing altogether and cause global sea levels to rise. This in turn could have a negative affect on coastal and river course, soil fertility, biodiversity and reduce the opportunity to grow crops in some of the poorest counties.
Social Issues of Water Use
Drinking adequate amounts of water can protect health by preventing a range of short and long-term health problems from headaches, bladder, kidney and bowel problems to cancer. It can also have an impact on the ability to learn. Being well hydrated helps concentration and performance and reduces tiredness and irritability
Ensuring free access to water and promoting a regular intake throughout the day is vital for promoting health and providing a healthy learning environment
Water use around the world
The average daily water use per person in the
• UK is 150 litres
• USA is 500 litres
• Developing world is a mere 10 litres
But what about future generations?
Changing weather patterns can cause desertification, where farmland becomes desert. Global water consumption increases at more that twice the rate of human population growth and is set to triple in the next 50 years.
Almost half of the world's population lives in 263 international river basins, two-thirds of which have no treaties to share water. This may lead to local and regional conflicts in the future, when water becomes scarcer.
The world's six billion people already use 54% of all the accessible freshwater found in rivers, lakes and underground aquifers. By 2025 this is expected to be 70% and if per capita consumption continues to rise at its current rate, we will be using over 90% of all available freshwater within 25 years.
Economic Issues of Water Use
Drought can have a huge economic impact on a region, increasing the cost of supply and drying soils can increase the risks of burst pipes making the resource even scarcer. Higher supply costs have an impact on agriculture, forestry, the natural environment, retailing and tourism.
Flooding can have an even bigger impact on the economy, besides the obvious cost of damage to buildings and restricting movement, flooding can damage large areas of rural and urban landscapes and the regional infrastructure. By 2080, the annual cost of flooding in the UK could be as much as £80 billion (10 times its current level).
Reducing Water Use
Your water use is doubly expensive as you do not just pay for the supply but also for disposal. Reducing your use will also reduce your disposal costs.
Good housekeeping and maintenance
There are many activities your school can do at little or no cost to help reduce water use and costs. Personal behaviour can have a huge impact on water consumption.
Ten things you can do now at no or little cost to reduce your water use are:
1. awareness – raise awareness and let everyone know how important it is
2. awareness – take regular meter readings and investigate any increases in use, remember leaks may be underground and invisible
3. awareness – ask everyone to report any maintenance issues (such as dripping taps) as soon as they are spotted
4. bathrooms – fit water hippos into toilet cisterns – these are often freely available from your water supply company
5. bathrooms – fit flow restrictors or automated switch off (e.g. push taps) to taps and showers
6. external – consider the water requirements of new plants, and purchase drought resistant varieties where available
7. external – only water grounds when it is absolutely necessary and encourage the use of low pressure hoses or even better watering cans on specific areas
8. external – install a water butt to collect rainwater to provide water for the grounds
9. swimming pools – if you have a pool cover always use it when the pool is empty
10. maintenance – repair dripping fixtures such as taps, which can waste 4 litres of water a day; and leaks to pipe work can be even more costly.
Rainwater recycling can reduce the amount of water treated and pumped through our water networks and also reduce the risk of flooding. Rainwater can be collected for use externally to water gardens or for use in flushing toilets and washing clothes.
Grey water recycling can reduce water use but some health and safety issues still need to be overcome before this technology can be used extensively in the UK. Water is usually collected from washing activities such as bathing and washing machines and used to flush toilets.
Find out more by following the links below.
Oxfam Water Education resource
Water in the School
