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Bangkok, October 1988

© PGCHS-KULeuven,KasteelArenberg,3030 Heverlee,Belgiumtel. 32 (0) 16 220931ext 1371telex 25941 Elekul b

MarleenIterbekeandPaulJacobusarestaff-membersof thePostGraduateCentreHumanSettlements(PGCHS)of the Catholic University of Leuven(KULeuven) inBelgium, secondedto theDivision of Human SettlementsDevelopment(HSD) ofthe Asian Instituteof Technology(AlT) in Thailandin the frameworkof a cooperationprojecton Low-CostHousing, directedby Dr Han Verschure

This project is sponsoredby the FlemishInter-University Council (VLIR), fundedby theBelgian DevelopmentCooperation(ABOS) with assistanceof the FlemishAssociationfor EducationalProgramsAbroad(VVOB) andthe KULeuven Althoughthe know-howis developedwithin the frameworkof the Low-CostHousingProject,theNGO ‘PROTOS’ hasseperatelysponsoredthe constructionof 25 water tanks

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KULPGCHS

KATHOLIEKE UNIVERSITEIT LEUVENPOSTGRADUATE CENTREHUMANSETTLEMENTS,LEUVEN, BELGIUM

AlTHSDASIAN INSTITUTE OF TECHNOLOGYHUMAN SETTLEMENTS DEVELOPMENTDIVISION, BANGKOK, THAILAND

AN INNOVATIVE WATER TANK PROJECT

CHUMPUANG, THAILAND

Authors Marleen Iterbeke

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Sponsoredby

PROTOS-BelgiumImplementedby

KULeuven-PGCHSIn Cooperationwith

ALRO-Khorat

As a follow-up of the

KUL-AIT LOW-COST HOUSING PROJECT

Sponsoredby

VLIR, ABOS and VVOB

PaulJacobus

Director HanVerschure

Typing Sripen Dandhanin

Lay-out Anawat Pedsuwan

- -

1. THE PROBLEM OF WATER SUPPLY IN THE NORTH-EASTERN PROVINCES OF THAILAND

Length of dry periods in Thailand. A dry month receives a meanannual rainfall of less than 60 millimeters. (source; Thailand,the Environment of Modernisation, L. Sternstein, 1976).

In the Northeastern provinces of Thailand,water supply is a more serious problem thanelsewhere in the country. In spite of aconsiderable amount of rainfall, large-scaledeforestation together with arid soilconditions turned the Northeast into aproblem area for water supply. Hence, cleanwater is scarce in many rural areas in theNortheastern region. In the dry season ofthe year, a lot of villagers have to walkmany kilometers, pushing their carts whichcarry plastic water containers, and wait forhours in order to get some water from a wellor a pond. Although such water may containundesirable substances or diseases theyhave to use it because it is all they have.

During the wet season, from May to October,rainfall is abundant. For example, theaverage amount of rainfall in KhoratProvince is 1.146 mm. This amount ofrainfall on one square meter of roof areawill provide enough drinking water for onesingle person over a period of 300 days at arate of approximately four liters of waterper day. With a large roof area, a villagercould store enough water for drinking andother purposes for his whole familythroughout a dry period of six months.Therefore the villagers should have largetanks which can store sufficient rain waterfor consumption throughout the dry period.Since most villagers are very poor the costof the tanks should be as low as possible.An estimate of the water requirements of afamily throughout a dry period may bederived from the product of family size, theamount of water each member requires perday, and the number of days in a dry period.For an average family of 7 persons and a dryperiod of 180 days the following consumptionestimates are found in various publications(see bibliographical references):

DRY PERIODS

-Jan

Lenght of dry period

2 months

—4

—5—b

o 50100150km

- source 1.18 liter per capita per day (lpcd)if carried by hand 22 680 1/year

- source 2.4 lpcd/drinking55 lpcd/total domesticconsumption

- source 3.6 lpcd/drinking and cooking 7 560 1/year

- source 4.15 lpcd/total domesticconsumption 18 900 1/year

- source 5.20 lpcd/total domesticconsumption 25 200 1/year

Various types of water tanks have beendeveloped over the years. Many have beenused successfully but their cost is stillrather high.The cost of a water tank per cb.m. decreaseswith the size of the water tank. The biggerthe tank, the cheaper the storage cost percb.m. of water.

For example:(1983 prices, 25 Baht = 1 US$)

Type of tank

concrete, bamboo

reinforced tank

plastic tank

steel tank 1,5

ferro-cement tank

ANNUAL RAINFALL

5 040 1/year

69 300 1/year

Mean rainfall

a

1200 milimetres160024004000

0 50 100 150km 0”

Contentin cb.m.

521

1

Cost/cb.m.in Baht

491,—248,-

2700,-

1400,-

580,—Annual rainfall in Thailand. (source; Thailand, the Environmentof Modernisation, L. Sternstein, 1976).

1,2

2. KUL/AIT LOW-COSTHOUSING PROJECT FRAMEWORK

LOCATION

In May 1987, a rural demonstration house wasbuilt in Chumpuang District, KhoratProvince, as part of the Low-Cost Housingproject which was set up in 1985 by the PostGraduate Centre Human Settlements,Catholic University of Leuven, Belgium(PGCHS-KULeuven) in cooperation with theHuman Settlements Development Division,Asian Institute of Technology (HSD-AIT). **

The main aim of the demonstration projectwas to demonstrate alternatives in terms ofdesign and building technology at affordablecosts, while encouraging cooperative andself-reliant building practices and incomegenerating activities. At the same time,this project was also integrating some ofthe national policy goals with regard torural development in Thailand. The use ofwood for house construction was as much aspossible substituted by locally availablelow-cost building materials and techniques.A low cost solution was proposed to easeproblems of sanitation and water supply.People were also trained to produce buildingmaterials under cooperative management inorder to generate additional income.The technology adopted was simple, labourintensive but not capital intensive, ofrelatively low cost and high standard.

(**) see Iterbeke, M., Jacobus, P. andVerschure, H. Rural DemonstrationHouse, Chumpuang, Thailand, PGCHS-KULeuven and HSD-AIT, May 1987, pp.16.Location of Chumpuang District in Northeastern Thailand.

The production and application of three‘new’ building components was introduced: aninter-locking soil-cement block, aprefabricated concrete joist and aninterlocking concrete door/window frame.The two-storey dwelling having 42 squaremeters floor space and basic sanitaryfacilities, was designed according to Thairural life-style and housing customs, with asleeping area on the upper floor and akitchen that opens out into the yard.

The overall cost of the house, excludinglabour, was 24,600 Baht (approx. US $ 950).A 14 cb. meter water tank was built makinguse of the same building components i.e.soil-cement blocks and concrete flooringsystem.

Top left : traditional rural houses. Rainwater is stored inferrocemerit jars.

Bottom left : the KUL-AIT demonstration house and water tank inChumpuang.

3. THE WATERTANK PROJECT

4. DESCRIPTION OF THE WATER TANK SYSTEM

Upon completion of the demonstration projectin Chumpuang, it became clear that not onlythe house but even more so the water tankattracted a lot of attention from thevillagers living in the area.Indeed, the soil-cement water tank provideda simple and low-cost solution to one of thevillager’s most urgent problems : watershortage.A Belgian NGO ‘PROTOS’ (Project group forTechnical Development Cooperation) wasapproached and agreed to sponsor a projectto construct 25 water tanks in ChumpuangDistrict. In cooperation with the Agricul-tural Land Reform Office in Khorat, theKUL/AIT Low-Cost Housing Project took theresponsibiJity for further research anddesign, institutional set-up, training andsupervision during the implementation of theproject.This year 25 households from villages 2, 6and 8 in Chumpuang obtained an interest freeloan. 25 water tanks were built over a fivemonth period by a locally based BuildingCooperative of villagers who had receivedtechnical training in the framework of theKUL/AIT Low-Cost Housing Project.

4.1 Design

Two different designs have been proposed, a8200 1. tank with tap and a 16250 1. tankwhich is built partly under ground surface.

16250 l.tank 8200 l.tank

Height 2 m.(1 m. under 3 m.ground surface)

Width 3.15 m. 1.95 m.Length 3.15 m. 1.95 m.

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SECTION A~Top left : a 16 cb.m. water tank is constructed half underground surface.

Bottom left : the wall of the water tank is built withinterlocking soil-cement blocks.

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REINFORCEMENT PLANSov.r)

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165 OU -MS

They are basically made of interlockingsoil-cement blocks and prefabricated con-crete components:

- the interlocking soil-cement blocks areused to built the walls of the watertank. They are produced through compres-sion of lateritic soil mixed with 10-15 %of cement and water, using a modifiedCINVA-Ram press. After moulding, theblocks need to be air cured for at least7 days.

- prefabricated concrete joists form themajor component of the concrete coverwhich is built using the same techniquesas the concrete flooring system of thedemonstration house. The joists areprefabricated by means of a simple steelmould. A thin reinforced concrete slabis poured once the joists are in place.

All these components are produced in thevillage with simple tools and equipment.

C.ecr,t. foNnda$lon1/3/5

$4SI.., ,.lnI.rc.m.~t 6mm

4.2 Construction

The construction of the tank involves thefollowing stages:

- earth work: the site of soil excavationfor the production of the soil-cementblocks is further dug out (if required).

- foundation: a steel reinforced concreteslab is cast in situ.

- walls: interlocking soil-cement blocksare laid dry and reinforced with steelevery 30 cm., liquid cement grout ispoured to achieve a permanent bond.Every. 3 to 5 layers a ‘ringbeam’ is builtby means of soil-cement channel blocksand reinforced concrete.

- rendering: a 15 mm. cement rendering isapplied to water-proof the walls.

SI ~SC Il.cEs ~

$3

St..I rslnforc.me.t 6mm

REINFORCEMENT PLAN(Wall)

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~UNDATIONPLAN

Foundation and wall reinforcement plan of a 8200 1. water tank.

- cover: light, prefabricated concretejoists are placed 60 cm. on center. A 6cm. steel reinforced concrete cover iscast on top with the use of light, re-usable wooden form work.

4.3 Cost

The cost of the water tank with a storagecapacity of 8200 1. is estimated at 3,500Baht and the tank of 16250 1. at 4,900 Baht.Part of the construction cost, 2,400 Baht(8200 1.) or 3,600 Baht (16250 1.) isrepaid by the beneficiary to the sponsorinto a revolving fund. The repayment isstarted immediately after the completion ofthe water tank at a rate of 100 Baht permonth over a 2 year (8200 1.) or 3 year(16250 1.) period.

Comparing costs with other water tanksystems, the soil-cement water tank iscertainly competitive in the market with anaverage price of 427 Baht (8,200 1.) and 302Baht (16,250 1.) per cb. m. Moreover theinvestment cost will partially return to thevillage. Indeed the labour-cost, 42 % ofthe total cost of a 8,200 1. water tank and33 % of a 16,250 1. tank will be paid to thevillagers working for or member of theBuilding Cooperative. The people buying awater tank, also take part in the productionprocess and in this way there is littledraining of resources, both monetary andnon—monetary outside the community.

Top left : the water tank is rendered to water proof the walls.

Bottom left : a 16 cb.m. water tank nearing completion. Alayer of channel blocks is being laid and will be reinforcedand filled with concrete to form a ‘ringbeam’.

Top left : perspective of the 16000 1. water tank illustratingthe steel reinforcement grid inside the soil-cement walls.

Top right : a 8200 1. water tank was constructed near theworkshop of the Cooperative.

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Bottom right : rainwater is collected from the roof by means ofgalvanised iron sheets or plastic tubes.

5. A BUILDING COOPERATIVE, RESPONSIBLE FORPROJECT IMPLEMENTATION

6. SOME REFLECTIONS ON IMPLEMENTATIONPROCEDURES

A Building Cooperative was formed immediate-ly after the completion of the demonstrationhouse. The Cooperative (representing 20 mem-bers and share holders of villages 2, 6 and8 in Chumpuang) was the main actor responsi-ble for the implementation of the water tankproject.

The Cooperative proposed a list of benefici-aries with adequate affordability to repaythe loan. Furthermore its members were res-ponsible for project management includingaccounting, purchasing of constructionmaterials, supervising construction work,organizing labour, collecting the monthlyrepayments from the water tank owners etc.According to the designs which were providedby the KULeuven staff, the group completedthe construction of 15 water tanks and aWorkshop for the production of buildingmaterials.

The Village Cooperative was building thewater tanks under contract for a fixed priceagreed upon by the project sponsors. Super-vision of the construction was done by thefuture tank owner and a technician trainedby the Low-Cost Housing Project. When apackage of five water tanks was built, thework was evaluated by the KULeuven staff andanother set of five water tanks wasimplemented.At first, it seemed that the Cooperative,working on a profit basis, bargained for thebest deals at the local building materialshops and that work got organized efficient-ly without much time delay. However, noprofit was being made and although the watertanks were being built, the Cooperativenever operated on a real cooperative basis.The Village Headmen, also members of the

Cooperative, took full responsibility forthe construction of the water tanks, employ-ing labour, purchasing building materialsetc. They managed everything without anycontrol on their decisions by the othermembers of the Cooperative because of theirposition in the social hierarchy of theVillage. As a result there grew somemistrust with the other cooperative members.

Hence, a new organisational set-up wasproposed in which full responsibility wasgiven to the future water tank owner tomanage and supervise the construction of hiswater tank. Before, the total budget for aset of five water tanks was transferred tothe Cooperative. Now, the budget for onewater tank was allocated directly to thewater tank owner. He hüiiself, was to managepurchase of building materials, labour etc.Cooperation between the applicants of thesame village was still encouraged but notimposed. The Village Headman of eachvillage retained his responsibility inselecting the applicants and collecting themonthly repayments against a small fee. Itwas also decided that fulltime technicalsupervision was no longer needed as manypeople in the villages had become familiarwith the building techniques.

It can be concluded that the overallapproach resulted in the successfulimplementation of a low budget project witha clear institutional set up, littleoverhead and a high impact on short-termbasis. Moreover, villagers learned how tomanage a project and developed constructionskills that will generate additional incomefor their families.

-. - P.. ‘~. -

I

A proud family in front of their new water tanK. This 8200 1.tank’s capacity equals the capacity of 5 to 6 popular ‘redjars’ as seen on the foreground.

7. BIBLIOGRAPHICAL REFERENCES

Chindaprasirt, Prinya et al., A Study andDevelopment of Low-Cost Rainwater Tank, KhonKaen University, Thailand, 1986.

Continuing Education Center, Report - Semi-ET1 w370 436 m403 436 lSBTnar and Study Tour in Thailand and Indonesiaon Ferrocement Technology for AfricanOfficials May 28 - June 12, 1983. AsianInstitute of Technology, Thailand, 1983.

Darrow, K., Keller, K. and Pam,Appropriate Technology Sourcebook.II., Stanford, California, U.S.A., 1983.

Etherington, B.E., Interlocking soil-cementbricks: a modified çINvA-Ram brickmakingmachine, Asian Institute of Technology,Bangkok, Thailand, 1983.

Fricke, T. B., Bamboo-Reinforced ConcreteRainwater Collection Tanks. A. T.International, Working Paper, Washington,U.S.A., 1982.

Iterbeke, M., Jacobus, P. and Verschure, H.,Rural Demonstration House Chumpuang

,

Thailand, PGCHS-KULeuven and HSD-AIT,Thailand, 1987.

Proceedings of the Seminar on Technology forRural Development, 16-17 February 1985,Khon Kaen University, Thailand, 1985.

Sharma, 0.C. and Gopalaratnam, V.S.,Ferrocement Water Tank, Booklet Number 2,International Ferrocement Information Center(IFIC), Asian Institute of Technology,Bangkok, Thailand, 1980.

Thanh, N.C., Surface Water Filtration forRural Areas: Guidelines for Design

,

Construction and Maintenance. EnvironmentalSanitation Information Center, Bangkok,Thailand, 1982.

Thiensiripipat, Nipon., Final Report onBamboo Reinforced Concrete Water Tanks.Khon Kaen University, Thailand, 1984.

Watt, S. B., Ferrocement Water Tanks andtheir Construction. Russel Press Ltd.,London, England, 1978.

Vol.