Non-Motorised Irrigation Of Small Farms From Streams No-32 1991

27 Pages·1991·0.42 MB·English

DEVELOPMENT
TECHNOLOGY
UNIT

Working Paper No. 32

Assessment of the Potential for Non-motorised Irrigation

of Small Farms ‘rom Streams in Manicalard, Zimbabwe.

Development Technology Unit, Department of Engineering,
‘Werwick University, Coventry CV4 TAL.
Tel: [phone] Fax: [phone] Telex: 311904 UNIVWK
Working Paper No.32

Assessment of the Potential for Non-motorised Irrigation

of Small Farms from Streams in Manicatand Zimbabwe

January 1991

‘Note: The Werking Paper supersedes WLP. dated Oczaber 1969

Ackeowedgemeut? thy UUITS sappy Eo ackiowleage cre
Tinanetal support of che Jk Cretseas Develeoment aca
Aucration ic the Fesearea repoeced 12 chas werai7E
paper. (Ole Conerace kic92; aa Sf Hyaraulie Ham Pumps)

“This documens for cucatation ousie the O:T.U. ror tuthar copies contac
DDavolopmant Techrolegy Unil, Deparimant of Engineer ng,
‘Wanmick Universi, Coventry C¥4 ZAL
(0) 525122 Fax: [phone] Telex: 211904 UNIVWK G
Manicaland Irrigation

APPENDIX C: PHOTOGRAPHS

‘A traulle-powered pamp (ght) and
a plastic hydra pamp (below) are
shown under test at Chitepo Adult
‘Training Centr, Boada, Manicaiand,
Zimbabwe in Septersber 1989,

‘The uesile 5s of University of
Zinnkalwel oughborough University
‘design and the hydram of Warwick
University desiga,
Maricaland irigation

[ASSESSMENT OF THE POTENTIAL FOR THE NON-MOTORISED IRRIGATION OF
‘SMALL FARMS FROM STREAMS IN MANICALAND, ZMBABWE
by members of
‘Warwick Uriversty Development Technoiogy Unt
‘ngooperation wth the staf of Maricaland Development Association.

CONTENTS
Page
1. troauston 1
2. Inigaien tecnnotogy 3
2. Chole oftecnnique for smainoloerinigason 3
22 Thehytrauic ram pump 5
23 Tho teeadle pump 9
3. Asoainigable by owes trom siroams n
4 Panvems of Inigated agscutucg “4
42 Dry versus wotsaason igattr: “4
42. Nutilon and lod security 8
43. Mairusiing tt ity 6
44 ‘Sai arosion 6
45 Enonariee and evidence ot userirlarast 16
5. Social and fogalimpleaions 18
© Asmalhoderinigalon development pregramme 19
7. Coneustons 2
APPENDICES
A: Analysis ol hycralieram pump petormance a
Bi: Shor Bbtography cS)

Financial Nate.
‘Av costs are, unless otnerwisa dasgnated, expressed in 1990 Zirbanwoan datas 21 2 me
ven USS1 = ¢82 Development fechroiogy Unt, Warwick University, Coventry, England.
Maricaland Inigaion

1, INTRODUCTION
‘The inteneifeation of agdoutura in Aitcan co rvieg, especialy in tha tracional sector of hele
‘ural economies s recalvng much atertion today, Tis escabtion of agrcuturat acy ie
sen a5 an essential means of achieving solt-aufclaney in ood prodecion (deste ising
Populalons). is alo sven as a way'oinerwasing rural comme generon, wnich WouKd Tava
‘the vahtabe aiect of removing & pre cause banvnd over rapid urbanisation. However,
‘nies conederaple care ig taken th ianericason cf land-ube car lead to ineversile
degradation of sols. Wiiletdrrply irpraved faring techniques can do much to ncrease
Yeks, a substartial improvement n agiculusal preckesion uavally aleo entails creasing
‘uch inpute a he water, oriser and energy used In cutvaion

In Zirbabwe the productivity of most and s waler did. In vary few araas can mere than
‘one rairfad crop ae harvested each year, and in mueh of southem and westem Zinbabyts
‘ven that one crop ts often ast ina dry year. Drought rll programmes are then operated.
‘Soaconat malnutton is 280 a cancam. On lage commarcal fms, rigatan using water
resarveles or Boranckes ie widely puactted with goed resuke the hectarage $0 ejalad has
gown rapidly In the last 30 years. On small- holdings in:he tess fer lard al the Communal
‘Areas, iigation ls, by contrast, quite rar dacpite being under-sctimatedin oficial eureye,
‘The farmers (ofan wornor} have Ite capil, lectiiy fr pumping ia not available, the plots
_20 too amal or steep for eommercal regen equipment tobe acahom and its
maintenance can ae a problem. For exarle a paotdtven purTpsat is {a0 fomertul, clly
and complex for afantar of 2 hectates and ye is rot wasly stared. lrigetion offen cones
wth farmers “runimurn is sraagles.

Parl of Manica is mourtainovs and has tte best ralmalin Zimoabwe, Much ot the Non
and East of me Province s casced as “Agroecolagical Zone I" the naka! map of “Natural
‘gions and Farming Areas”, (3 cimata aavaraga whichis cet by the steep and rocky
falote of much ofthe land}. Many of tha steams are porannial. Depit tui there fs sl along
fry caacen in winlor ate Iie ran fas and most cropland les ide. Basides tho these
felatvely largo rigaion schemes operated by DERUDE, a ine gravity-ted irigaton is
pracisod nthe Communal Area, bu there ae very fow pumas, long ‘UTTOWS oF dame or
seasonal warer storage. Within he ccnsiats of diy-season aream lows and other demands
(on surface waters, a substamtial emansion of smaltnolderinfgatin seems paseible using
steam wator Coly altar date will he nesessary 1 tap ufderground water, which i
‘genaraly nee costly te access and Yas spacial probleme {Ike safnation and deplaton} in use.

‘The Manicaland Davalopment Association (MOA) was formadin 1980 ta assis marl grasstoot
‘commuritios wih heir social, econoric and agcutural dovelopmect. MDA has twe Trang
‘Gontros and District Davalopmamt Comnitogs In eevcn gisies af Manicaland Prov nce,
undertakes agriculural Waring and evtencon it ompleys donate technology instructors to
limprove nutiion and womens wetara ard promotes rural noamegeneralow using
Appropriate lachnologies. fs mai ocuss upon the needs of thos Iving in Communal

‘Areas. In olation to infgatan, ts nomtiam Herbert Chigpo Traking Cente (HCTC) a! Barta
is wl placed for beth demonstatons and extension work.

Warwick University has had connections with HCTC: since its eary cays, The University has
wii as Engineering Department a Duvelepnars Technology Uh (OTL) that speclanses in

Page
Marsala rigation

‘al indusriaieaton ard the design of lecinologles Jor nual development in Asia and
especialy) Alea. ne devia thas bosn researching slowly fr same yours isthe

ator powered “hydrauic ram pump" pump, saeking ip mod tracitonal designs so that they
‘ight bo madein small workshops at a cost that would corm ther use for irigation. Early
rotaypas wars build sk HTC in “986 and 1988, Revert tho CTU has abtained British
Government funding to accalaala ts rasoarch inl re pure. Tha DTL has is wth
Programmes using ram pura in Zaria and Zire,

‘The development of appropiate pumps is only ane part of any programme to promete
inigation on smalfialngs. There are many possibi inigation techniques (not all using
‘puMpe) and many factors aecting th viabity of any one esohed ina particular area. A ring
‘month pofid of pur toxtng and improvemont at HCTC, invlving ihe placemat of & OTL
repreceriatve thereto work wih HCTC's Appropiste Technology Section, wes slarod in
Aust 1389. was. decided fo alach to isa shor su ofthe relavance of ron-oiorised
‘Smale irigaton in Manicalard. The as of slucdy cariad aut batwwur rig-Aupst
ane ri-Sapternbar 1989 wore:

1 oidentiy major social, sonomie ax goographical constants an tha
‘xpancion of inigaion al emai pst in Communal Areas

1» todavorp a batter specication tr water iting devises
1» to examine the agrcutural opfons available forthe use of extra water.

Aturher fold euudy was undertaken in Cecerrbar 1980, maint fo carly the ikly area of
irigable land. By is ime one ofthe pumas boing lasted al Bonda nad cu oantiruously for 9
‘montis giving greater coidence ints sutabily for niga apglcations.

“The Working Paper descrbas the ings of tae studies and racnrde ta inialtast
perlarrance of two pues fone wato- powered, the cther huran-powered Installed nea’
Model Farm of CATC. The Paparis necessary bet and single, reflacting th brevity 2nd
Simply af he ehias. as haen urinan party te givea framework 10 mors datalled
‘evalualionin the tuture, and parly a Back up a request for inigaton programme funn that
MDAie mating

Page 2
Maricaland ligation

2, IRRIGATION TECHNOLOGY

21 Choice of technology for smalholder irrigation in Manicaland
“Theta are vary many ways of supplementing vara increase agrcatral yaks; niga i
a well developed art We are ooncamed fete with a specie group of armas ina specie
faraa, Namely hota fing in Communal Aaa othe moister pane of Marigaland, Existing
insgation of hor dry soason pardons fe by gravy fea ftom stare, ore 2 secondary ube ot
‘nator primaily provided for domestic purpages, inthis content tas been aready argued that
‘the expansion of iigaton using surtace watery should take precedence over the reduction
of inigavon using underground wats fam aquitsrs.

(oF he vaous methods of appiing waterio a pct, thase that are mast aint in water use ~
for exarrple spank and ei inigaion are alsa those that need the mst expansive
‘seqipment and rignee wale’ prassurns. For doln reasons tnay are ro sutabie primary
techniques fora target group. Applicaton by tur, negepipe or buckal Nas therolore been
assumed, athough in some places paniaary permeate sos may rete othe: ieaimert.
Farrow inigation needs conderabla lang preparation (of tha sama sort as erosion irntalor
‘on slaep plots): a variant I ra loocng from ator turow, whict hewaver Is Iniciar in
‘ator usa ard can oat sol erosion.

‘Sine dy season rvar ows are ony a smal ration af Summer flaws, soasonal storage
‘pind sma dams i common on large commercia lars. There as few examoles of sus
reserva in Communal Lands. and in some pats of Maricaland sulable sits would be "ard
Ja ind. Tha enet and dograe of cacperalion batreen individual emaholder: neceeary 10
‘coneinct and safely malfain dams i quite high: dam construction should net nowraly be 2
pat of ary selomaraged irigaion echames for smal-scala farmars, Thara Is arurrbot ct
‘govemmont administered zralhader inigallen sehomos in Zirbaaa whoro oxpensive
‘share facie (dams, boreholes) are employed: however these achemes are usually
subsidised fo a dogrea that makes thar poor madls for copying.

Movement of wate rom source to plot car be by gravity orby pumping. Cxlating smallholder
inigation uses gravy, butthere ara many utes whore the lurow leading fom an abstacion
Poli on a steam tigate larel woul! be vary costly Io cruafe ard ical fe mairaie. Lo-g
‘ura, turrows trough permeable sols (needing Hniog| and tums tough zacky feraln
(needing blasting) areal they be too expansive, Corteurrumows nisod protactng from
darrage oF station by cross Hows during rains, Thor is no dauts scope Tor increasing
‘raviy-tedimigaionin Varicalae,cometimas.in conjunction wih the creation of very smal
{even termpocary} dame to act both as version structures ane! as avemight wate stores.
‘Some of he acavity-ed sts row in usa contravene the Stream Bank Pratecion Regulations,
‘ing wihin 30 metres of a walercourse: enforcement of hase regulations is expected 10
Hightonin ature,

Fora majoty of now sles Goma form of water iting willbe required or wil be preferable to
‘he alamatve of using along row is specticaly pumpad ination thata cansidoredin
tho rast of his raport. In commercial igaton, engine- dlevan pumps {the cheapest cost
around 24000) ot sactte pure are Ivartably usod. These are usually unsoanamic when
inigating los that 2 hectares. Mains elecricy is rarly avalabo at syoamcides ane!
Dhote-voltaic elect is tartoo cost. Windpurping leo has tar toe high a captal cst ‘or

Page 3
Manicaand Inigaton

‘nigation purping in Zimbabawe,

an on ses wth sepectaly favourable wind regimes,

“Thrag walee-ng techniques meet Ine requitement hr tow capa cont ow running cost and
_simploty,namaty humarr powered, animal paweedd ard! wal powered purping.
“Animal-cnven devices are not Known 1 avaiable in Zertabwo, atnough Fey hava eon used
in Asia tor many cariurs. They may become ct more intorest tae gan increaca in he
se of draught animals n Manscakan, but ca et conetivte a good option today.

‘Human powered inigation, a aaa of smal los, is widely practised. Applied to plats of ven,
2 nectar ht becomes very atous, Such a pit requires about 5000 lye bucks (10000
'ires) ol water per day, about 4.5 buckels por minute for 4 hours per day. Evan with 3 cara,
such a rata coukl only 2 mairtainoc f the cislance carved ware fea than 90 metres and the
Jit oss than say 2.5 moires. Pumping i uch preisraba Wo casting. abil ermpkoys energy lar
mote een. OF tha many lypes of “nard* pump, thosa thal maka goed uss of back and.eq)
_nuscles ara superior to Inaba only using arm muscea.M should be possbi fr a team of to
poopie to vata 10000 Ties par dy traugh 5 metrea using a human powered puro. ln
‘ountioa wharo human-powered irigaton ie widely used, all of above 9 matras ie reqewed
0 Uni to wally. Higher His gra Rowavor used in Bangladosh,

‘Tho last toahnique lited shove ie water-powerad pumping, This is ony feasiba for iting
water rom streams. hily areas ae 4 use9 eve envacted trom the smal fall of a lange owe
fei a smal fow to a haight. There ae tow watar-pawared pumps avalabla. In China water
"urbine-pumpsots are muuetactured. anda law afer davicns wrist in atc counties, ut
the only widely used water-citvan pur tha nycrauc am pump. Even tis uneuitaba tor
inigation nt usual high-cost, ng, low: capanty ton: Nowever a vanant designed
epeetizaly flow it irigalion in Afca is becoming avaliable ands deserbed below.

Pagad
Maricaland ingaton

22 The hydraulic ram pump
Background.

“The automatic hyceauic ram haa bean used sunnasctuly inurl aveas or Hing water far
nearly two hundred years. Tha hydaule ram ea pumpang device which utleae anergy Kom
‘he fall of alow of watar of. fracton of tha supply toa much great Neigh. Bacause i has
‘only 2 moving pats ard no bearing, thas a ropuialon for rally and low maltonance. 3
ivory nature canned be used to pump “stte® wale from pond or wos: tls ostfcid fo
iy araa whave alrean gractorts aro rolatvly sleep,

Existing designs
Commertialy mandacured ram aumpe are usually made trom steel castings and have taba

importad to Zimbabwe, Thaee are raraly uted for rigallon because of:
1m Ihe hign cost ofthe rams and large ciamotar pipe networks needed for
inigation

1 the ack ot expenenced echnical Eack-Lp i asset nystom design on ste
i= tho urrolablity of spares supply and acooss to maintenance,

‘The reasons are paricularly mye ior smaltarms in erota areas. Secondhand Blakes ram
pumps command high prices (254000 upward) tn Zimbabwe today.

‘Warwick Design
“The low plastic ram purrps veloped! by the OTL! ae zimed! at small-scale nigation
Alea. Tha main dasig7 ebjecves ae:
1m topreduce a pump which canirigate,rfany, smal fam at x height of 2m
above a watercourse

1 to make it possible te mantacture within the county of usa, prolraly In 2a
areas, using componens and tooling techriques widely available

1= tocroaie omoloyment in workshops with both manufacture and malntananca

Albydraulic ram pump system (refer to diagram on the next page.)
“Tha diversion sinucture channels water lw rc a pipe or conduit which folows tha contour
(wha sight stope} away lor he srearn to he dive tank, Tre drive tanks at point about
am abave tke stream. Separale cive pipes being the low doven the 2m head" to cve the
paralll pumps (batwaen 1 and 4 pumps). A common debvary pipe takos the pumped water Up
fea livery tank. Tha system can daar atau 7 ofa stream ew at any single cation.
-Anather sat of pumps at another locaton down stream could tt anothar 7% ha trea Now
rarmairing and son. This 7% aeaeimum could be increased Wthe dive head were greater
‘hae 2m or the delivery Read less then 12m.

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Maricalane inigaton

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