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“Water is the driver of Nature” Leonardo da Vinci

Without water, nature doesn’t work. The average adult human being is made up of 60%–70% water.

If we can’t get water, we get dehydrated. When we get dehydrated, we get gradually weaker and eventually become unconscious and die. This happens when we lose about 10% of our body fluid. Dehydration often also involves loss of the minerals that help keep our bodies working properly, such as sodium and potassium.

If we can’t get clean water, or we can’t clean the water we have, then we have a problem. Diseases carried by water kill millions of people every year. 2.5 billion people (including just under one billion children) don’t have basic sanitation – that’s access to safe water and the means to dispose safely of dangerous waste water. Every 20 seconds, a child somewhere in the world, dies as a result of poor sanitation.

This may seem a bleak situation, and it is. However, many organisations across the world are working to improve it. Even basic technologies can help to transform lives, and access to safe water is one of the most basic things human beings need to survive. A human can live only a few days without water, but with adequate water and no food, a human can live for many weeks. We’re not giving you specific figures here because the time a human can survive depends on lots of things – illness, temperature and shelter to name but a few, but the relative times are telling.

Practical Action is a charity that uses technology people can often make

themselves to create life-changing solutions in countries all over the world. Access to safe water, or the ability to clean water, are crucial to life for humans and the crops and animals they grow to eat. It’s also important to be able to store it without it evaporating or getting contaminated. Even better, once you’ve used it, there are ways to recycle it.

We’re going to show you some of the techniques Practical Action uses to help people get, clean, store, use and recycle water, and ways you can help make a difference from your classroom.

Go to practicalaction.org/water-and-sanitation-14 to find out more.

Ideas required before undertaking a WATER project:h Knowledge of the impact of low or no rainfall

on the environment (it may be helpful here to collaborate with the geography department in school)

h Knowledge of the water cycle and its impact on the life cycle

h For projects on solar water heating, knowledge of thermo-siphoning would be useful.

Water pump, Kenya

MICRO IRRIGATION Introduction

Conventional irrigation systems, such as channel irrigation and wild flooding tend to waste water as large quantities are supplied to the field in one go, most of which just flows over the crop and runs away without being taken up by the plants.

Micro irrigation is an approach to irrigation that keeps the water demand to a minimum. It has been driven by commercial farmers in arid regions of the United States of America and Israel in farming areas where water is scarce.

Typically, these commercial irrigation systems consist of a surface or buried pipe distribution network using emitters supplying water directly to the soil at regular intervals along the pipework. They can be permanent or portable.

Many parts of the world are now using micro irrigation technology. The systems used by large commercial companies are generally quite complex with an emphasis on reducing the amount of labour involved. Small-scale framers in developing countries have been reluctant to take up micro irrigation methods due to the initial investment required for the equipment.

A number of organisations have looked at ways to simplify and reduce the cost of micro irrigation resulting in the approaches of drip irrigation and pipe irrigation.

For these small-scale irrigation systems not only should the technical aspects of the system be considered such as: • access to reliable water sources • a secure and well-fenced garden • basic gardening skills • the crops grown

The social aspects should also be of concern to ensure the irrigation system will be of benefit. The social and economical factors will include: • capital and financial management; credit facilities • the availability of external services • maintenance • market opportunities for the produce • willingness to show other farmers the technology

Drip Irrigation

Drip irrigation uses low-cost plastic pipes laid on the ground to irrigate vegetables, field crops and orchards. This technology was developed in the 1960s for commercial use. Circa 1990 a US firm called Chapin Watermatics developed a low-cost system called bucket kits, which use standard plastic buckets and lengths of hose that could be cut to the appropriate lengths.

Figure 1: Manduru Unit, Maragwa. Kenya Practical Action staff demonstrate drip irrigation. ©Practical Action/Shaun McGuire

Rainwater harvesting in Zimbabwe

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Getting It

RainWaTER haRvESTing If you’re harvesting water from rain, which is the best way to do it? Can you select a country and situation and find several ways to harvest rainwater? Or, if you see a rainwater harvesting scheme like a hafir (a reservoir in Sudan), can you find a way to reduce losses of water – perhaps by evaporation or water seeping away – inexpensively?/

For general information go to practicalaction.org/rainwater-harvesting-8

For technical briefs go to practicalaction.org/irrigation-answers and look at:

h Rainwater harvesting

h Underground rainwater harvesting

h Water harvesting in Sudan

iRRigaTion TEChniquES and damS Can you simulate the use of a land contouring system and find ways to improve it? For example, could you find a way to improve sand dams and make them more effective? Would using woven grass or twigs in the middle of a sand dam make it more effective? Could you design a test in the school lab to see if this worked? Can you find a simple way to test how permeable rocks are?

For more information go to practicalaction.org/irrigation-4

For technical information go to practicalaction.org/irrigation-answers and look at the technical briefs on:

h Sand dams

h Dead-level contours

WaTER PumPS Practical Action uses a variety of different pumps to get water from underground. Look at these and see if you can think of a way to improve them, for example by making one of the parts using a less expensive material. One of the pumps is called a Play Pump, a merry go round which uses the energy created by children at play to generate energy. Can you think of how you could use other play equipment to generate energy to lift water? How else could the energy generated by play be used?

For general information on treadle pumps go to practicalaction.org/treadle-pumps-2 and for play pumps go to practicalaction.org/playpump

For technical information go to practicalaction.org/water-pumping-and-lifting-answers and in particular look at technical briefs on:

h Human powered water lifters

h Treadle pumps

h Hydraulic Ram pumps

h Wind pumps

WhERE iS ThE PRoblEm? Where in the world is water least available? Use climate information on rainfall and temperature alongside population and think about where there’s currently the least rain, and compare that to data from the past. Can you see any changes? Does the past help you think about the future and where the effort to solve these problems should be targeted?

Windmill made from scrap, Sri lanka Treadmill, bangladesh

Treadle pump diagram from a technical brief

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Cleaning it

WaTER diSTillaTion How much sunlight is needed to distil one litre of water? How can you make the solar distillation method more effective? Simulate it in the lab with a desk lamp and a small-scale set up. Change different factors and see what you can learn.

What other methods of water treatment have been tried in the developing world? Which have proven most effective?

How can we remove dissolved salts from water safely and easily? Is solar distillation the best method? Come up with some others and try them.

What effects do metals dissolved in water have? Where are they very problematic?

Why (other than for human use) do we need to process water for?

How effective and how fast is sand filtration? Can we make the process work better?

Can plants help us clean water? In some areas, reed beds are used to clean water, can you find out about this?

For general information go to practicalaction.org/water-distillation-1

For technical information go to practicalaction.org/water-quality-and-treatment-answers and look in particular at the technical briefs on:

h Solar distillation

h SODIS

h Water supplies for food processing

h Slow sand-filtration water treatment plants

h Water treatment systems

h A small-scale arsenic and iron removal plant

Storing it

RainWaTER haRvESTing Research the different techniques used to store water, and the issues with each. Can you see why each is useful in different situations?

How can loss of water by evaporation be minimised?

How could you store water at your school to help preserve supplies?

Can you design a storage tank using fewer or different materials for a given area of the World?

Schematic of a single-basin still

Water filter, Nepal

Clean water, Sri lanka

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For general information go to practicalaction.org/rainwater-harvesting-8

For technical information go to practicalaction.org/rainwater-harvesting-answers and look at technical briefs on:

h Rainwater harvesting

h Underground rainwater harvesting

h Cement water jar

h Water harvesting in Uganda

h Pumpkin water tank

h Brick dome water tank

damS What effect do different rock and soil types have on the way water escapes from storage areas? Can you test this in the lab scientifically?

What’s the best way to minimise loss of water through barriers, dams and earth walls? Find out how it’s done now, think of some other methods, and/or build a simulation in the school lab to test one.

For technical information go to practicalaction.org/rainwater-harvesting-answers and look at technical briefs on:

h Sand dams

h Dead level contours

Using it

ZEER PoT FRidgE What effect does changing the clay pot used in an evaporative cooler for another material have on its effectiveness? What other porous materials could you use? (Non-porous ones won’t work as the water has to pass through the pot to evaporate)

Where and how is evaporative cooling used around the World?

How can you increase the efficiency of an evaporative cooling system?

For general information go to practicalaction.org/ zeer-pot-fridge

For technical information go to practicalaction.org/crop-storage-and-preservation-answers and in particular look at the technical briefs on:

h Evaporative cooling

h Evaporative cooling – the clay refrigerator

SolaR WaTER hEaTing Can you test the differences in effectiveness between different types of solar water heating systems?

Can you test the effect of altering components in a solar water heater and changing their surface finish (e.g. from clear tubing to matt black tubing) on the energy transfer?

Zeer pot fridge, Sudan Carrying containers of water, Sudan

Pumpkin tank, Sri lanka

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How effective is the thermo-siphoning effect in a classroom solar water heater? (You can find out about thermo-siphoning by looking at solar water heater websites)

For technical information go to practicalaction.org/solar-energy-answers and look at the technical brief on:

h Solar water heating

Reusing and recycling it

RECYCling WaSTE WaTER Can you think of reasons why recycling waste water is important? How would you persuade other people it was important?

Can you find out why animal waste getting into rivers or streams is a problem, and what the solutions are, both here and elsewhere in the world?

Does your school recycle water? If so, how? If not, how much water could be saved, and how much money would this save your school once the system was paid for? Can you find other local buildings that re-use wastewater? Where in the World would wastewater reuse be a useful system? How could it work?

You can find information about ways to clean water used in homes on the following sites:

Centre for Alternative Technology Water and Sewage Pages – http://info.cat.org.uk/water-and-sewage

The Renewable Energy Centre – www.therenewableenergycentre.co.uk/waste-water- recycling-and-sewage-treatment

Integrated Water Strategies, North Carolina, USA – www.waterrecycling.com

Rainharvesting Systems – www.rainharvesting.co.uk

Useful Links

ThE global WaTER PaRTnERShiP www.gwp.org The Global Water Partnership’s vision is for a water secure world. They support the sustainable development and management of water resources.

un-WaTER www.unwater.org UN-Water strengthens coordination and coherence among UN entities dealing with issues related to all aspects of freshwater and sanitation. This site includes reports by young people as “Youth Reports” on key issues accompanying technical and policy reports.

un-WaTER STaTiSTiCS www.unwater.org/statistics.html includes statistics on World issues with water.

WoRldomETERS www.worldometers.info This site includes some basic water data, including information about water usage, availability of clean water and deaths from water-related disease.

WaTERaid www.wateraid.org WaterAid’s mission is to transform lives by improving access to safe water, hygiene and sanitation in the world’s poorest communities. This site includes information for technical and young audiences, including statistics, about the challenges of water and sanitation.

global iSSuES www.globalissues.org This web site looks into global issues that affect everyone, and aims to show how most issues are inter-related.

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