The survey areaThere are about 50 hamlets in the OyoLocal Government area, each withsimilar populations and using pondsas water sources. During this study,from January to May 1989, one personin seven of the population had anattack of guinea worm. The communi-ties, because of earlier health educationinterventions, were already using filtra-tion (19.2 per cent), alum (25 per cent),and boiling (18.3 percent) to treat theirpond water. The mean water consump-tion was 27 litres per person per day.The pond water contained cyclops, theintermediate host of the guinea worm,in the range of 30 to 350 per litre ofwater. The communities also sufferedfrom ring worm, diarrhoea, helminthicinfections, and scabies.

The study was carried out in thethree villages of Ajelaunwa, Iyalase,and Araromi, in the Ifeloju LocalGovernment area of Oyo State. Thepopulation of the villages was 50, 60,and 50 people respectively, most ofwhom are farmers. In Ajelaunwa andIyalase there are two ponds, and atAraromi there are three. In each villageone pond, which is less than lkm fromthe residential areas, was used duringthe wet periods, and the other, whichis about I to 2km away, during the dryperiods. The communities were verywilling to co-operate, as they sufferedbadly from guinea worm.

Building the wellsIn siting the wells, factors such asnearness to the pond, flatness of theground, perviousness of the soil, andrelative elevation to the pond weretaken into consideration. Using simpletools, such as a long iron crowbar anda hoe, a pit is dug and aIm-high oildrum which has had the top and bottomcut out of it and any dents flattened isinserted into the pit. Depending on thedepth, two or three drums can beplaced one on top of the other, and thegaps sealed with cement, but the useof more than three drums is notfeasible. One of the tops or bottoms isused as a lid, to which a lock is fixed.After arranging the drums, the gapsbetween the lining and the pit are filledwith either soil or a gravel and sandmixture.

water supply was found to be mosteffective in the control of guinea wormin the long run. But the provision ofsanitary wells will cost money, and themajor expenditure is the digging andlining. As a result people often try toeconomize on the lining, which oftenresults in a poor quality structure thatcollapses. This article describes aproject which provided shallow wellslined with used oil drums. The drumsare easily available, and they protectthe wells so that cyclops-free water canbe obtained in the communities atalmost the same site as the infestedponds.

GUINEA WORM IS endemic through-out Nigeria. Pi. recent national surveyindicated that of the 6112 villagestested, 5270 were found to have guineaworm, and Oyo State recorded II 584individual cases (12.6 per cent of itspopulation). In the Ifeloju Local Gov-ernment area of Oyo State, past effortsconcentrated on providing alternativewater supplies to badly affected com-munities, supplying monofilament ny-lon polyester gauze filters, treatingwater sources (usually ponds) with achemical insecticide, Abate, and intro-ducing health education. Of the variousmethods tried, the provision of a safe

Shallow drum-lined wells for guinea wormeradicationby M.J. Ayotamuno, M.K.C. Sridhar, W.R. Brieger,A.V. Sangodoyin, and P.N. VyneTreating ponds that are infested with guineaworm cyclops can be difficult in rural areas. Adifferent and inexpensive method is to install ashallow, drum-lined well near the pond, so thatthe water is filtered through the ground beforeuse, eliminating any cyclops that might bepresent.

A shallow drum-lined well in situ.

30 WATERLINES VOL. I I NO.2 OCTOBER 1992

A hand-dug well is an improvement on an open pond, hut it may he difficult tokeep the sides intact.

Where there is no clean alternative people will have to use the polluted source.

the ponds, because the clay contentrose as the depth increased. The soilshere contained 12 per cent clay in thetop Im, which increased to 25 per centat 3 to 4m. At Araromi the soils hadonly 5 to 7 per cent clay. Anotherfactor at Iyalase was rusting, whichcoloured the water initially but disap-peared after a few day's use; the waterwas clearer when it was used regularlyor in the mornings.

The rate of recharge of the wells (inlitres/min) in dry and rainy periods wasfound to be Iyalase: 0.36 and 0.44;Ajelaunwa: 0.30 and 0.61; andAraromi: 0.44 and 0.55. From this andthe water consumption pattern, it isdeduced that the wells could meet atleast one-third of the water demand indry periods and slightly over half thewater demands in rainy periods.

The cost of a drum-lined well isabout half that of concrete-ring-linedweBs. At the time of this study, adrum-lined well three drums deep hadcost us Naira 350 (US$35) whichincluded labour, smoothing the drums,a cover lock, a bucket, and transporta-tion. The cost can be further cut downif communities are encouraged toparticipate in more effective ways.

All the three communities re-sponded positively to this new device.

80cm of soil had 34 per cent clay andthe bottom 160 to 240cm soil had 22per cent clay. The drum lining has notsignificantly affected the turbidity andsuspended solids. At Ajelaunwa, on theother hand, the turbidity and suspendedsolids were higher in the wells than in

Several VISitS were made to thecommunities, and the project staffworked through the leaders in thecommunities. The senior adult in eachof the 28 houses was interviewed tocollect the basic information. Theguinea worm eradication objectiveswere explained to them, and theninformation such as occupation, sex,guinea worm infection experience,water demand, and behaviour andattitude to the use of installed drum-lined wells was collected throughdiscussions and questionnaires.

Water samples from each of theponds and wells were collected in cleanbottles and were examined for cyclopscounts and water quality. Cyclopsnumbers were counted under a high-power microscope after large quanti-ties (10 to 50 Iitres) of water wasfiltered through a IOO-mesh nylonfilter and the residue resuspended in asmall quantity of cyclops-free pondwater. The pH value, turbidity, sus-pended solids, alkalinity, hardness, andcalcium, magnesium, and chloride lev-els were measured.

ResultsThe quality of the water in the pondsand in the newly dug drum-lined wellsis given in Table 1. The results indicatethat there are no cyclops in the wells.The hardness, alkalinity, and calciumlevels were much higher in both thepond and the newly dug well in Iyalasethan in the sources in the other hamletsbecause of the local geology. Thelevels of turbidity and suspended mat-ter are high because of the highquantity of clay in the soils: the top

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