c ica Brief 0.44: Em rgency rsupThis Is an overview of the principles of providing water in emergency situations. It outlines theplanning procedures necessary for ensuring adequate supply, rather than focusing on design.

As well as food, shelter, and medical aid, providing clean water is usually one of the highest prioritiesIn the event of an emergency. It should be considered alongside Immediate sanitation measures,however, which are just as Important in controlling many of the most common diseases Qund Indisaster situations (see Technical Brief No. 38).

Responding to an emergencyAn appropriate response to an emergency depends onwhether the emergency affects people where they live,such as In the case of an earthquake or flood, or whetherthe population is displaced as a result of other pressuressuch as famine or war. Although the measures may differ,planning considerations for water supply are similar inboth situations.

Planning what to doThere are several planning considerations:

Demand assessmentHow much water is needed?Location and protection of water sourcesWhere are the nearest/most convenient sources ofwater? How can they be protected?Water treatmentWhat is the level of water treatment required for uselconsumption? What methods are available fortreatment?

Figure 1:A refugee camp

Water distributionWhere will people collect water from?

Collection and storageHow will the water be collected? How will it bestored for domestic use?

These questions must be considered as soon as anemergency occurs. It is also important to prioritize action.A phased action plan comprises:

• Immediate measures (to sustain life);• intermediate measures (from about 2 to 6 weeks

afte( the disaster. or the arrival of refugees in acamp); and

• long-term solutions (from about 6 weeks).

The actual duration of these phases is usually determinedby three factors:• Accessibility of the disaster area or refugee camp

for local, national, and international assistance;

• the nature of the disaster; and• the availability of water, materials, and skilled labour.

YO.I 0.4 PRIL 199

c ef 0.44:E e e cyw ter p y

Demand assessmentDemand estimates will clearly depend on local conditions.T ble 1 shows guideline figures only. It ISimportant to notethat water quantity alone is not sufficient to ensure thehealth of refugees. Good sanitation and hygiene educa-tion and behaviour are also essential.

Location of water sourcesThere are three types of water source'

Existing sourcesWhen disasters occur where people live, it may bepossible to revive some or all of the existing watersupplies.

Allow Sf Ie st 40% eXTrafor unforeseen c"cumstances and waste.

Table 1. A guIde for assessing the demandfor water in a disaster situation

Fe dmg c ntres 20 - 30 lipid

TOIlet lIushmg Pour flush latrines 2 - B lipidwater

Cisl rn flush 40- SOli d

Animals ( 'Ppro .J Callie 20 - 30 V dHorses mul s, don eys 15 - 25 VhldSheep goals, 10 - 20 I/h!d

Camels 2 lIh1d

I((/ga/lon Very vanable. but 3- 611m/dtypically

,f" __

Figure 2: EXlsttng water sources may be revived

Local sourcesLocal sources of water in areas where existing sup-plies are inaccessible due to the nature of the disast9r.or where refugees gather away from existing commu-nities; may include wells boreholes springs, streams,ponds or rainwater.

Distant sourcesWater will usually be available from existing communi-ties - which may be some distance away from thedisaster area or refugee camp. The impact on thesecommunities of an increase in the volume taken froma water source must always be considered.

5 patienVd

40 - 60 I/pallen d

3 - 5 lipid

15 - 20 lipid

Minimum for survival

Desirable emergencysupply

Out-patIents only

In-patients (excludingcholera hospitals )(not Includmg laundry)

Health centres

IndIviduals

A note about water qualityNormal practice is to supply all water of a qualitysuitable for drinkmg

Treating water to this standard takes time - evenuSing the Simplest of methods. It is often appropriate,therefore. to supply treated water from a distant sourceas an immediate measure, where possible. At thisstage, cost is not usually a problem, as both govern-ment and non-governmental organizations are gener-ally willing to mobilize short-term resources promptly.

The most common form of supplying water in this wayis by water tanker. Though expensive. tankers can bemobilized quickly and offer flexibility of distribution.

Nevertheless. immediate consideration should be givento alternative sources of water and ways of treating thiswater once it is located. Figure 3: Water tankers

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Figure 4: Dlggmg an mfiltration well

Se«lementThe quality of water from surface-water sources, suchas streams and rivers, can be increased significantlyby allOWingwater to stand in calm conditions, prefer-ably under cover. This allows some of the suspendedmaterial and associated pollution to sink to the bottom.Some fine partIcles will not settle, but will remain sus-pended indefinitely, unless encouraged to settle by theaddition of small quantities of certain chemicals, suchas aluminium sulphate. This must take place undercarefully controlled conditions, as too much chemicaladditive will poison the water, and too little will notachieve the desired result of purifying the water.

Figure 6: Domestic water filters

FiltrationFor large populations, slow-sand filters provIde one ofthe simplest and most reliable forms of water treat-ment, but they occupy large areas of land, and reqUirecareful design and maintenance.

Small volumes of drinking-water, suitable for individualhouseholds, can be obtained from domestic filters thatallow water to pass through ceramic filter 'candles'.

DisinfectionAs a final precaution to ensure that water is bacteno-logically safe. it should be disinfected. This reduces thenumber of bacteria present in the water to a safe level.Disinfection is most effective in clear water. Chlorina-tion IS the most widely used technique, as It is availablein various forms and as some of the chlorine com-pound Should remain in the water, increasing thelikelihood that the water will remain safe to drink duringdistribution and storage.

Package water-treatment plantsPackage water-treatment plants are highly mecha-nized, self-contained units which, though small, com-pact, and quick to install, are expensive, and requireroutine maintenance by a skilled operative Th y havebeen used successfully in Turkey and Zaire, however,as one of several water-treatment options.

Water treatment (surface sources)At the outset, it is usually unrealistIc to expect the qualityof water supplied to satisfy normal water-quality guide~lines. Provided that the water is clear to look at, does notsmell or have an unpleasant taste, and is disinfected, it isusually acceptable in the short-term, but it should betested as soon as possible. There are a number of suitablewater-treatment options to consider as longer-term solu-tions. These should aim to provIde better-quality water.

Infiltration wellsThe sand and gravel deposited beside and below ariver acts as a very effective water filter So, wells duga short distance from a river-bank will usually providebetter-quality water than the river itself.

J/J';.

Figure 5:Allowing water to settle in a package storage tank Figure 7: A package water~treatment plant

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•C olea erg oey wat rs ppl

Water distributionAs noted above, water tankers are usually only suitable as

short-term measure. Water may be distributed moreefficiently using simple pipe network. Where possible,the dlstnbutlon network should be connected to a water-storage tank The tank may be filled slowly over a 24-hourperiod whilst allowing water to be drawn from It whenpeople need It most The pipes should be desIgned toc rry the maximum expect d flow (see Technical BriefNo 29).

The water collection pomt usually comprises a series oftaps attached to the end of the pipe network (see left). Tapstands should be evenly distributed throughout the camp,

nd must be strong enough to withstand heavy, some-limes continUOUS, use.

Collection and storageThe collection and storage of water by refugees fordome tic use is an Important consideration both in theImmediate aftermath of a disaster. and in the long-term.Refugees may have no means of collecting water from itssource. so containers must be provided

Contamination of water often takes placeafter the water has been collected from thesupply. It IS necessary. therefore. to providewater-collection and storage vessels thatar easy to use and keep clean

Hygiene education has an Important role toplay in ensunng that water is not contami-nated.

Figure 8 Oxfam water-collection point

Figure 9: Covered water containers

Further Information:DavIs, R.A and Lambert, R.. Engineering In Disaster Relief: A handbook for engineers and relief workers, IT Publications.

London. 1995M d cins Sans Fronlieres. PublIc Health Engineering In Emergency Situations. Paris, 1994.o lam Water Supply Scheme for Emergencies. Oxfam Technical Unit. Oxford, 1992.Re d, R.A 'Technical Brief No. 29: Designing simple pipelines', Waterlines. VoL10. No 1. IT Publications, London. 1991.Re d, R.A. and Shaw, A.J .• Technical Brief No 38: Emergency sanitation for refugees' Waterline;. Vol 12. No 2, IT Publications,

London, 1993Reed A.A., (ed.) Technical Support for Refugees. Lessons from recent experiences, Procepd'-1s of the 1991 International

Conference. WEDC. Loughborough UniverSity of Technology, Loughborough, 1993.Reed .. R.A and Smith, M D., 'Water and sanitation for disasters'. Tropical Doctor, Vol. 21. Supp. No.1. Royal Society of Medicine.

London. 1991.UNHCR. Handbook for EmergencIes, Geneva, 1982.UNHCR Water Manual lor Refugee Situations, Geneva. 1992.Waterlines, Vol.13, No 1, IT Publications. London, 1994.

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Prepared for IT Publications by Bob Reed and Rod Shaw

Water, Engineering and Development Centre (WEDC)Loughborough UniverSity of TechnologyLelcestershlre L 11 3TU UK. Fax +44 {OJ 1509211079

Thank you to IT supporters who have funded theproduction 01 the Waterlines Technical Briefs in 1995.We gratefully acknowledge your continuing support

Forty-fourth in a series of Technical Briefs lor fieldworkers. Technical Briefs Nos.1-32 are available in book form.The Worth of Water: Technical baels on health. water, and sanitation (ISBN 1 853390690) is available at £9.95 plus £2.50P&P from IT Publications, 103-105 Southampton Row, London We1 B 4HH. UK. Fax: +44 171 436 2013

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