ggo?lraford fFoloutfcol uolleFp^rl leuollua^uoc-uop

fi60lourlcaluolleffi'l*J l Jffil4,H lJdsto

lenuEW

Government of NepalMinistry of Irrigation

Department of Irrieation

ManuaIof

Sprinkler Irrigation Technology

NON_CONVENTIONA"'#:{;{!#TECHNOLOGYPROJECT

2063

#wwg! , l t e r n a t i o n a iYJat rr i!4ft l' I a?i4r.^?il, n s t i t ' u t e

FoREWORDS

Sprir*lerlrrigationis.corrside.r:d*non.conv-clll3'u|irrigationinourctltrtext'Erm ttrotrgh this t,""n""itgi i' i" u"'-*in& i;&-ttltf bac'k' it is not so popttlar atrr()rrg

$r farmers *r.,o u,.J'lr-r'uri6med *itr-,. fonneniiinar irrigatiori'*y*'rr*r' ionsequcrrtiS- it

&s mr errioy rt " fif;;f i'nJ1"i1v 11'"'i'iiiili',"!iiit*i;f;; bepartnrent of lrrisatrott

dgr has rrot so rar put ar1v. s.ub1a"ti"i';iffi aimid "t

p"iiii"-ihg i\ u,t -1t] clli'r":ti-r'e

supplerrre*t to convefiJorii'irrigatio" *V*i*i*- tlrere *"d ;; p-;;eived' dempnd l'or tire

sarnr. T\ris s.rust o'.ri"*"J.ifi 9r, "jniJJ'J dema'd diiutin rnodality' of trper*lttttt

aOo'ted by oepartnienibt trrisari- ," iirltm""tliiui gi1 ilfi;biry has been excluded

fronr being i*pr"r"iii"i'in ,&1" una'J;Jplil;l'""r,i{:b" ;i iii'frr':1i:"i Ail this hus

definite hunran ,r*"#|J, 'iinfiution'""i'*tii'

Lf"t p{ t*p"1i*:n*'owing prirrtaril'"- to

ever increasiru piilv-"u.r,:ti*-i."qrir'ff;fiilid;t itiidution scheme developtrrenr'

tecrr'ical stafrs or b,ipurtmenr or lTid;ti;;:;* *.$ ,'inrJ*td-ono,ut teih'ical

and otlrer aspe.tr-oi arip irrigatioil'iirrnoiogv. conJq'uentty., u rt"gl for soure

co'rpretrenriu" guideiino.in ar.ielgidfr'ilt'gulion,ttft"nit has iong'been felt among

irric,ariorr tec.,,rrcrans in Nepar. rhi;I;;al"t* u"rri"pi"par"a-riith..t'e vierv t<r

adclressirrg tt,i, ,p;ii" n.Lo h, we, is i" iir**i"ate ari rSiitll-l"r"rmation regardirrg

;;tpilsfiion teihnologY in NePal'

Etlbctivenessofsprinklerlrrigationremains,contingentupotlull:t'"fvariablessuc. as ctirnate, soii propirtir., ,yp.*"Ji'iifi-t iti' Hglgtlein"tience gained at the local

re'el arig'eo *i,ilil5"i;';d-iiirii ir;i*, fip;tt"nt trran"irffirffioir that is exrracted

rior' resear"n 'n-oing. in differen, *tilr",'li.J'ffi;:diit+# #;tt'id;'.lt *Th' tlrere is

er*rus' space undni-"a ror conti'uoJJ;';'1i;;;"a.uno uneriJirig';i ilrit nranual' lt .as

bee'-hopeO trowenii-that for ,t" ii,"J'iJi"i,'itil,o-til*'i"tiiti-cirtaintv. fulfl;ll its

"'i lh iill'" rfiiti u" t YLast ly ls i r rcere lyapprec ia teef for tsput inandthan$al l invo lved i r r , the

g.".puruiiun rir tnis manual'

, rrtt h1}',n"A's'yrr

\Madhu Sudan l'audel

Director Geueral

DePartttlent of lrri gatio tt

Abbreviations - r ' : 1

ADBN: Agriculture Developtfank of Nepal

APP: Agriculture Perspective Fhh '

- 't;4f--'Cl: Coarseness Index

",Dol: Departmentof trrigatkxr ii:i

<F-

EIA: Environmental Imprct Arpsment

ETo: Potential E

FAO: Food and Agriculture Orguiization :

FMIS: Farmer's Managcd InigSig,n Systenr

GDP: Gross flomestic Product, , ] . :

HVC: HighValueCrop : -::? ,:

INGO: Internatfonal Non- Gorynelt Orgsruzation

IEE: Initiat Environmentral Extniirdtion

MnO: Management Allowed Deficit. : .,

MS: Micro-sprinklcr

NIT: Non-cqnventional lrrigatitirTechnology

NITP : Non-conventional tnifiitiffiirechnology Project

Con:tent:' li'iil[f;YfH""#;il;;i::: :::::::::::::::: -:::::::::: :::::: :::::::::::::::::::::::::::: ::: :::: l1.2 Inigation Techno1ogy............... ......... i

1 .2. 1 Conventional Technology.......1.2.2 No,nConventional lrrigation Technology.............. ........2

1 . 3 Spr,inlder :Irigation'Systern ....... 1..........L4 Sultebtlity rn Nepali Cs$text. ...........3I .5 Advantages of Spr.ir+ktre Inigation System ..........3I.(r l- inritations of Spr,inkler lr igation System ............:..........."..4

7- SIIRINKL:trII S'YSTEM COMPONI,NTS: .........-..6

l llllil'il.lil;Y-1:::"":::: . :2.3 Spr inklers: . . . . . . . . . . . . . . . . . . . . . . . .72.4 Miscel laneous..- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . t t2-5 Classification of tire'Sprinhler Imigation systenrs. ...............82.5.lrnpontant;considerations on Sprinkler lrrigation............ ..................... 10

2:6.1 Wettireg Circle: ...... i 02.6.2 Water Distribution and Overlapping of tlre,Spr-'inklers. ......".......... l02.5.3 Aepl,ication rate ........... ............ I I2,6,4 Drop size of precipitation ........122.6.5 Opaating Pressure.... ............... 12

3 lrrigdien.tfficiency ,................. t33.l Wa,ter Losses...-. . . . . . . . . . . . . 14

4. lSasic .fuslgs App.ro*ch of'Sprink{er Xrrigaiiom ........,........... 154.I {rr igation Water Req.uirernent... . . . . . . . . . . . : . . . . . . . . . . . . 154.2 Genera l . . . . . . . . . - i . . . . . . . . . . . . . .174.3 Des, ign Steps: . " . . . . . . . . . . . . . .17

5. Wale,r Distr&*rtion U,xiformity...G....-.....,..h ......."... t95- Oper,rtioa and lWa*nlsnauce of {he $prin*Xer 'Irrigatien Systern.. ....... 207. Irr:igetio*r,Seheduling ......2I

7.1 Gene.ra l . . . . . . . . .217.2 lrnigati,oreDepth ... . . . . . . . . .217.3 lrrigation Interval... .......22

t. PTiEASStrMSLED MICRO,SpRilNKLER IRR*GAT,ION,(pMI) ......238 .1 Gener :a l : . . . . . . . . . . . . . . . . . . . . " . . . 23

, ' ' . . ' ' , 23. . . . . . . .23. . . . . . . .25, , . . . . . .26........28

ManualSprinkle l rr igat ion Technologylntroduction..

I . INTRODUCTION

l. | lrr igation Status of Nepal

Agriculture is one of the largest sectors in Nepalese ecollomy. It providesemploynremt to more than 807o work forces and generates about 40% of National GrossDomestic Procluct (GDP). lrrigation plays the pivotal role in increasing rgriculturalproduction-and productivity. The importance of irrigation is more pronounced in thecountry like Nepal, wlrere agriculture is the main susterlance base of vast ma.ioritl, ugttre ;reople. The APP emphasizes ou " well controlled aucl year- rouncl irrigation" lbrhigh cropping intensities and to introduce FIVC varieties. Provision of the year roundirrigation facility has been further stressed.and incorporated iu the 1Oth Plarr.Meanwhile, lrrigation policy 2060 has been promulgated for the extension of irrigationfacilities.

Despite the continuous efforts of the governrlrent, the performance ol' theirrigated agriculture ii reported to be low. It is estimated that out of 2654000 Haagricultural lands, 1760000 Ha is potentially irrigable. Till date 1168000 Ha landreceives irrigation water. APP cites tlrat a mere 18 % of Nepal's arable land haC yearround well-controlled water. The proportion of non-irrigable'area in the hills' andnrountain is very high in comparison to the Terai

' Nepal has a long history of irrigated agriculture mainly thru FMIS. Abovt T5 Yool'tlre total irrigated area at present is still under these traditional schemes. Departtnentol'h'rigation (DOI) which was formed in l95l is the major institution invrlved in theilligation development in Nepal. Agriculture Development Bank (ADB/N) is auotherkey actor for the development of small scale irrigation developrnent. ln the recent yearsl/lr{COs and private sectors are also making irnportant contribution in irrigationdevef opnrent rnostly at local levels.-l'he

agriculiural land situated in the hill slopes ancl Northem Terai lack viableu'ater source for conventional canal irrigation. However, there is still a potential toirrigate significant fraction of the raihfed land tlrrough the development of snrall water

-<ources and application of efficient irrigation systems such as drip and sprinklersvstenls. In"view of this, DOI has established "Non Convetrtional lrrigation TechnclogyProiect (NITP)", which includes Irrigation teclurologies like Treadle Pump, sprinklerinrigat.ion, drip irrigation, rainwater harvesting, irrigatiotr tanks, and irrigation ponclsa^nd the like.

I'fhe

Tenth Plan and the lrrigation Policy 2060 have given special emphasis tofirese technologies which favors smallholder farmers located in the water scarce areasfrr the production of high value crops thereby contributing to National goal of povertyreduction.

Theobjective of this Manual is to provide basic information about the Sprinklerami .\licro-sprinkler inigation technologies and lrelp design the sprinkler irrigationspsteflls at given set of land, water and climatic conditions.

lJ lrigntion Technology

I -. I Ccrnn entional Technology

Existing irrigation systerns are mostly based ou the technologies to abstractnater from the riveristreams and ground water storage. The distribution is gerterallyrlrruugh gral"it]- flou' canal systems.

'fhose irrigation systems are being rbgarded as

Manual.Apsh*le;hnlgnrftion Techn o,logy'tntr,oductisn

conventisnal,tecl*nclogy. T,,l€rc *rytems ae ,located in alr.eacly 'faverable environtlretlt

in,ter.ms of ,quality.ar*d .qlwtby .CIf *axd # srder.

I . 2. 2 Non "Gcnuentional ilr*ig#im -$dxr*!qgy

T,,he .imig*iom te gies, $;*dsh ditr€r frsm the convsrtional canal systerns

and are,*u141i.vel] amdmn ilffiMs,,can be regarded as lxxrcohventional leclulology.

flrey ,rnay inci**de raqgp sf w*ry 'aequieitioa atd ryptict&ion tecfinslogies such as -

Sprinkler, Dr+p, T.,ts*., P'd" P*Fe, fle*e" Tr* ?rop ad so on. By and large

these teclmo,logies zue appo.pri*te {o the small scale frrting with linrited watcr

sources. T,he r,nain o:hiestiw of pr,onnoting tlrese technologies is to provide irrigation

facilities in the ma4ginal:rlands,where irrigation b,v surface methods is not l-easible dtre

to socio- tebhnicd;l:and,environmendal,reascns. Ttre fcrus of tlwse teclrnologies rvill bc'

in the areas of r€latively,water shnrtage,opprtunities f,or gxrtting high value crops tltat

will 'be targeted to the fanners rnnith srnall landholdings- Frsrn this perspective'tlre hills

and motrntahrs ,are tlre "nrost,f€asible regions for expanding ft{rcctrventional irrigation

technologies.

1.3 Spnir#er ilniga*ipm S.glr*rm

Sprirrkler irrigatior, also aanred as overlml irrigarion. is tlre ntetltud ol'

lvatering tlie plants,.ov,er ,the fi€ld in th€ f{}rm of sprar or f,iEt r**ich breaks'iltto dt:t4rs

or clrop.lets ,that is creafued by oxpe{ling rr.d€f, rmder Frcsslr€ t4rn a wozzle. SprinkleL

irrigatiul sirnu,Lates the nafira,l rainfall of cooolled ilrcquenc3- duration and irrtensity.

It erratrles 1o nrake ec<rnomical us of rrder throug*r crynralld and more or 'less

unifom appl,:ica;tion rJvef the erdire land surface- Bes*iles i*ig"tiaq ryrinklers can alscr

be el:l-e.ctive llretLLod of,applyi4g araler €clublc nutrient$ rnd grestlcides to tl'; cltrps' 'l'o

plevent pounding .and sultbce run.off spridders ae desigffid to apply water &t ir rate{lrat does not exc.eed,,infii+rationcapacity of tfie soil.

Though tlre history of Sprit*ler Inig*ion ddfs btrl. tcr ihe lS0 AD, tlte ttrairrt{evelopnrrcnl toek plaee af{er:$E€s{d Wortd l*ar rxith rh ir,sroduction of tigtrt lveightalunrinwl prys. I'he frrst sprinklers introdrtrd rn'ere sux.ing t1pe impact sprinklersr.vith rnovable laderals. Ftn*L.rer.der.elc'pmenr of the serffil€rs ied inta a wide mtlge ofsprinklers (nlicro sp,rinkler to 'Gun sprir{ders} lrith Elohile mac*i&e and automations. Inrecent years there ,has :been a rapid irrcrease in the rrse of Trirdilers-

Spdnklers genemlly need less sater and labour than surfm irrigation ancl catt beadapted toJnore sandy,,erosion prone soils on sloppl d $rduhing ground. So thistlpe of irrigation is suitable "f,or any toposraph]-. snitrs md crops rvhere otlrer srtrlirccirrigatiorr is ino{fieislterexpensi,ve or scil erosion is haar&rus- Sprilrkler irrigatiorl isparticular:ly sui,l.able in rhe fotl,owing conditism:

a) Coarse soil with ,poor water lroHiag caryity' r*icre it will be di{Ilrcult tomaintain waler distributi on by surface irrigation rrethod s.

b) {ilopprv- or l-trndulatfug topography wbse lar}d }eveling is impractical' orunecolromical.

c) Pocr w.a[er availabilfty urbse qu*ntil.v of r+'arer is not sufFlcient to irrigate bysurface meltxrds.

d) Feasibiility to grow h.igfu value crops - fruits- vege{ables- spices etc.

ManualSprinkle l rr igat ion TechnologyIntroduction

1.4 Suitabi l i ty in Nepal i Context

Though Nepal is very rich in water resources for irrigation, it is not properly util ized.As the population is increasing day by day, to cope with the increasing dernand of agricrrlturalproductiorr. irrigation development rnust be given higher priority. In Nepal, several large attdrrrecliurn irrigation projects lrave already been constructed bLrt their output is reporled to be veryl o r l .

It is a reality that agriculture irr Nepal is largely carried out under rain fed coriqJition. ltis est intated' that out of 2.64 rni l l ion hectares of cul t ivated lancl only about 1.76 nr i l ! iorr hectaresare irrigable. Large irrigatiorr schenres in Nepalare irrigating as little as43Yo of the plarrnecl rretarea during rnousoon antl l79to in winter. In most of the cases, tlrese sclrenres reqLrire li ighoperation and rnairitelrance costs and it results in furtlrer deterioration of existilrgirr fi 'asl.rurctures.

Nepal's ecorronr)' is uncloubtedly an agro-based ecorrorny. The high prr:duction ol'agricultural products not only depends upon the scientific nrethods of larid funning and highquality seeds but also depends upon the availability of sufficient'ivater. Orrly rain water is rrotsttffici:ent fcr high crop yields and therel'ore irrigation systenrs are to be nrarragecl f'or in-tirnequenching of the crop's water need.

Due to tlre settlement pattenr of the rural poor nrarginalized groups most ol'the lowerinconre bracket groups could not be benefited from conventional type of inigation facilities.l-lrey have to depend eitlrer on rainwater or any other fonrr of rron-conventional tnethod ofilrigation system of tlreir own. Lack of adequate infrastructures. poor cost recovery of opet'atiorrand maintenance in surface irrigation and slow rate of rehabilitation of farmer manageclirrigatiorr systems have prevented expansion of irrigatiorr s)'stems in Nepal. Under sucltcircunrstancbs it is higlr time to encourage farrners to adopt affordable, reliable and sustairrableirrigation teclrnologies in addition to the conventional surface irrigatioh metlrods.

Tlre terrth plan also emphasizes the new technological developments in irrigatiorr toirrcrease the productivity and decrease poverty. Sirrce there is no possibility of acquiringadditional land, what is required is to praduce lrigh aniouut of crops per urrit area of tlre larrd tocope with the demand posed by populatiori growth. This can be achieved via adecluate irrigatiorrfacility througlrout tlre year enabling to cultivate more crops. Tlre interest shown by the fannersirr crop diversification and increased population need make it irnperative to develop tlrosetechnitlues tirat provlde irrigation facilities rnore efficiently, throughout the year and to thosealeas that are beyond tire reach rvith traditional techniques.

Tlre hill region of Nepal, which occupies vast proporlion of the rain fed land oI thecountry, is characterized by steep ground slopes and relatively water scarce areas.Developnrent ol' su;face irrigation in these this ecological belt is lras lirnitetj scope due toter-ltrrical reasons. Under suclr situations NIT such as drip and sprinkler irrigation are tlte nlostzuitable techrrologies to enhance the agricultural productivity and econornic prontotiotr ol'tlrerural population. Sinrilarly, in the North belt of the Terai (Bhawar Zone) wltere the water tableus relatively deep, aud soil is nrostly porous tlre relevanee of the,dt'ip irrigation stattcls etpenriurn. Sprinklers, Treadle pump, Water harvestilrg tank are otlrer NIT solutions irr thep,l,aces rrlrere coverage with surface irrigations does not seern as a viable option.'l-hougli, thehills and Bhawar regions are highly suitable territories for the application of F'lT, it is rrotlrnrired to only in these regions. In general NtrT can lrave its potential applications itt trtuclrnx.re iarge eeographical area.

1.5 Adr-antages of Sprinkle Irrigation Syslern

Sprinkle irrigatiorr has several advantages over the convetttional surface irrigatior:rnrethods. J-he versatility of use in diftbrent [and, soil and crop conditions is the key features of

uilffiti'" lrrisation rech nolosvlntroduction

Tlte advantages of sp'itlkl" irrigation svstems are describecl irr the

the sprinkle irrigation'

followings segments'

u. Control over wateriSprinkler i,,i-gution offers higlr d-egree of control rvater application. The atrrount attcl

freque'cy water can ?"';;.,ilil; ;,y f i#.6;'i;';*ation. pounding, and rutt ofl carr.be

efinrinated tlrrouglr the corrtrol of water appf iJ*i"^t Tlris will lrelp rnaintain optinruttt growrlrg

conclitions of the crops and optimurn utilization of water'

Is' snvittrg !{rY,il'!{rrrigation, water is sirppried througrr the pipes and relativelv high degree of

water. distribution unifornrity can be attai;i;. tnus *rittr a gi'en quantiry of water, sprinkler-

r'etrrod can ir.rigate'nru"t.,'rarger ur"u ttru' trre flood irrigation" tn other words''irrigatiorr

requires less water per unit area. fn.a well-matraged s1'stenr tlre application eiTicierrcy of

sprinkler sygtem .un [" u, high as 75 oh as against so'x i' frood inig.atiorr. Snrall wate. sotrrccs

ui.o "u,l

be effectively utilized'

c. saving of Li!r"i*rru^u. requires less labor for operation arud rndn?gerrrent of the

irrigatio' system beJa.rse it does not ,"qrrir" same attention a*s the surface irrigation'

soil does ,ro, ,*J,o .ioa .rna., ,p.inr.i", irrigatiorr- Due to um.o strultTe^of the soil'

cost of tillage und-int", cultural ;p";i;;t iI minimize ' i* the rvater is uni{brnrly

distributed over the entire land area, i"rJ i"t"ring is arso nor nequired' This rvill sa'e

the cost of land preparation unO top'oii*itr' nigrt"ifertilirl*'*i[[ not tre disturbecl'

d. Protecti", "f ;;;;;i'oia nopi 7'9m the extreme n-eather condirions'

Darnage "iil;;";i;J "i"p

0l1. i" frost, w'ind can ['e nrinirnized in the

spri'kler-irrigateJ field. This i, *o,"j*fortant for the crops si sermination'and earll'

,iug". Sprinkler ii;;rt"; uiro.ontro*":tt;;;;;r. tinu '*"*olled applicatiort

prevents roit tto'ioi and also helps keep good soil structure

e. Atlaptatiort to marginul soils erate efficientll' o'Llmost any

Sprinkler ini{ation systems can be designed to c'p

topography. rrris meirrod rnay be an "ir""tiu"

tlchnique to irriga*e in the sloppy tefrattr'

irregirlar plots and marginal soil conditions'

i Em"';{u:::;{*f"ll,i!,r*^rsince convevT::.'lTIr5' rste€s are not reqtrired to

construct and almost entire *.u "o]ri

l" ,,,La for c* prn'*tuction' ofteu' the area

occupiedbybunds, levees,watercoursescoverappreciab' Ieamountof t l re latrdarea.which cannot b" ;;i ""atti"rtivation'g. Others , , - ,^) r -^* f incr demase

ffi *:ffi ',",',;:i:"x':;:iTg*",i.ii;ffi ?lil'*'*regimeintrresoil

1.6 Limitations of Sprinkler lrrigation System

a. High Cost.. . isprinkler inigation is relativel-v high. The rurtli'g

The initial investment of the spnnKrenT'Tl::I-l.:**J;" --'

cost is also highl";;";; sprinklers require energy for its operatron'

;: ;il; ;f 'fr ',il#;:' o r the :p'i"kf:::i':::: : 5l*iilTiff l[: or w aie r I r

the pressure is;;;;;;below the optimum, water '"iii;;;'t* unifotntlv distributed'

The probter, *iri u" *riou, whgn ;;;;;;te is too lo*" At low pressut -:' water jet

does ttor brcax up-and most.or.trr"-*ut"r tends,o iurr ar son'e dista'ce fronr r'e

sprirrkler. fne talfier drops will alsfd;;;" the soii "*"i"'"

and the crop' On tlte

4

ManualSprinkle lrrlgation TechnologyIntroduction

other hand,,if the pressure is too high finetalls close to the sprinkler.c. Effect of the Wind:

Water distribution remains poor if the sprinklers are operated in the wildyconditions' The fine sprays from sprinklers can be easily blown away by the wipd,which will distort the wetting patterns. This in turn will upset'the itrig;ioit u,rifor,rrlty.

El 931_'n' "rna "rilIlilorspersa l

d- Leaf scorch of due to salt.

- If the irrigation water is saline, it can result into salt injury to leaves of theplants- This is more important to'the salt sensitive crops.c- Clogging of the Nozzle:lf tlre irrigaJi^ol watel contains suspended matters such as debris. inorganic impurities,le nozzle of the sprinklers can be blocked. Small size sprinklers are rnore vulnerable tolilogging problem.

spray will be developied in form of misi that

^ 4 - l

E'{s2lsJ

t r l3 0 3

Oidinc.r ko{6, Sprinkler (m}

Io

I

3At sallslaclory pressure

ground not walered. '

EfT'-In

-7z

ManualSprinkle lrrigationp,a^t i .al Anolications

The components of a typical unit of sprinkle

divided into lhe following:

a) Pressurized Water Source

b) Pipe Networks (Main Line, Lateral , Riser)

c) Sprinkler Heads

d) Other Acc"essories

Layout Plan of the Sprinkler lrrigation

The basic information about the oomponents is described in the

2.1 Pressuriled Water Source:

irrigation system can be broadly

tbllowing sub-heaclings.

For small and medium size sprinklers the operating head varies

3Ometres. Depending on the waler source, the following methods are

water soufce u'der dEsirect pressure at the inlet of the unit.

a) lnstallation of Pumping Unit . t : , -- ^,^-.^]:^..\b) Gravitational Ener[y lWater s,ou{oe / tank located at higher elevation)

"i Direct connecting from the supply line

2.2 Pipe Networks

Generally, a sprinkler system consists of the following pipes' r

a) Main Line 1ro,ru.y. water f,rom source and distributes to the sub main' Irr the

configurations *itirout sub main, mainline delivers water directly to the latelals'

betweeu l0 toused to obtairt

Water Source

ManualSprinkle lrrigationPractical Applications

Mains may be either buried or portable type. The portable types are made ol'lightrnaterial such as aluminum, or plastics.

b) Lateral delivers water from the rnainline to the sprinklers. lt can be pennanent orportable. lts size is srnaller than the mainline. Laterals are laid along the contourof the land. t

cl Risers: The vertical pipe connecting laterals with the ,pri,r'kl"r head is :alled riserpipe.

Yrious types oi sprinklers are comlnercially available. Depending on the mode ofnion- sprinklers are carl be classilied in the following two types.el Fixetl llead 1-ype

Rotating type

The fixed head sprinklers do not have rotating ;rarts.Tlrey ara characterized by short rarlge but high intensity.Water is sprayed through the fixed nozzle. Normally theyproduce fine droplets and therefore best suited firrnurseries.

The rotary sprinklers operate due to the impact df thewater. The comrnon types of rotary sprinklers are

a) Rotary Impact Sprinklerb) Reaction or Arm sprirrkler andc) Butterfly sprinkler

Various lmpact spinklers

$otary impact sprinkler operates due to action of the water jet striking to tlter,r'hich deflects the drive arnr about tlre vertical axis of the sprir*ler.

'l'lre

the spring restrains the drive-arm and thus tunrs it back until it strikes thesprinkler body with an irnpact. This irnpact rotates tlre sprinkler. Hence. tlre

lwtion of water leaving the nozzle and spring loaded arnt cteates a torclue*out rotation of the sprinkler. Some sprinklers are gear driven by a small

with the sprirrkler lread.ir rype of sprinkler is available in single or double nozzle forms. Tlre dorrble

have trvo nozzles - a rauge nozzle and a spreader nozzle with diflbrent

JltSFinklers:

Manual

PracticalSprinkle lrrigation

rH"t.iJ.fl'"fryl:.'"" ;::; eader nozzle is

tltrows. .flris irttPro r'-----

s',*tt.t thau the range nozzle.'.

#L:ffi :if; :l"#i:i'enyiriii,"^:::TJ,,:$iH:jl:-gesbetweenGetrerally' tne opcrort"e "'--- iy tutga radius ot'throw.

meter head of wat* *d,:\ll::"",::T[rouqh a torque created 1l*1'#ffi t1'llii::,",l,",i1:f".,1?t! jT:::ili:l':13;,::'Jff illlll:f :-";in;:,xlT:'J:4fi .Til-iitilil;lir*m5ffi t3,ll'*l'

f::"m,:f #lli.X"i*::i'F:i:i1*#:trLtationorthebutterlr"v-ln a Dutrstrrr rl,rr""'--- - ,n in a cifCulaf pattern.

swivel u,rO*ut"t is ipread in all directto

2'4 Misceilil:"$: above *E:i-'.::oJ::*::';3::]H;f'*

arso contain rccessories

like - water nleter';;ii";t' tont*t'vutn"t' ti"t' tlends' plugs etc'

" ; l:-..o'::T:"$'ff :iilffi;:'::;l:,111'i iill "srerns

can be cr assi ned i'to trr e

following three tYPes:

a) Perutatreut SYstem .- )b) Setui-Permanent SYstem ano

"i FullY Portable SYstem

a) P e r m a n :#J :'f $.," n, i, ar so car I ed :il::':;f H- iilHT#;1ffi

m po tte n t i s

perrra'e'try fixed. No equipmgl, 1"".a, ," i" ,rt*".r "".d ;;

; o"ri"l-O-:l"w grottttd'

[lsuurrypo,ioft|ieiarrdisi,,iIi.li"i;;i::'.''':'';ffi*:TJilffill.;valves t. clirect ,t.,. no*r.

-l'his type of system :"q"t,T*';,5;;" labour cost is

*il#';;'';*'d',;1:i"ii:l[l:,yJJ:l'i,-fi "##-"'il fr ;ru*F'orpipes'

.nir"r.1"-11i,.l1^::1"J.,il::nilfi;"-#rffiT*il'#:e: 'd"-p'"d to irrigate higher

valucr cl'ops suctr

- Jt-

#F

25 to 4()

*t

lret6

;

ManualSprinkle lrrigationPractical Applications

b) Senri- Permanent System:ln a setni-permanetrt system, all the pipes and punrping units are permanently

installed, but laterals and sprinklers are rnoved from plerce to place. After sullicientirrigation at one position, strrrinklers are disconnected fronr the laterals and subsequerrtlvnloved to the next position. T'he process is repeated until the whole field is irrigatecl.This systern costs less tl-ran the pennanent system because it requires less quantitr, ol"pipes arrd valves. However, the pipes nray not last long clue to liequent urovernelrts ilrrclexposure to tlre weather.

nartziar{a z rfugaa

Se mi-permanent Sys te ntc) Fully Portable System:

In a portable system, both the pipes and sprinklers are shifled graduall,v atlillbrent part of the field. In some cases mainline and purlrps are fixed while in othcr;ases whole system including pump and the main lines are lnovable. When the irrigationrs conrplete in one position the whole equipment is moved to the next position manulrlly.

Portable system is considered most economical as fewer pipes and sprinklers,'Trcate more area. This type of system is sirnple to use and allows flexibiliti, ol'-r"'eration. However, it requires more labotrr to move the equipment.

-*.rf i*'IF

ilF.areq'd||le:Pd

W,

-t'I

I

dpiinr.r" tttis.l-Tl

2.6 Important considerntions on Sprinkler Irrigertiott

2 6 r w€ui s:,l'lLl o**,,r of t\e,1,r1a,::1,:i:JJ::lt$'J::[:i:i*'l:];iT:iHl'

wind). The dista'Jffilr sprinkrer to the outer tagt olJti#;;;t. than 50 nreters

'l'lre radir'rs or tn'o* nitilt n"i" f"w-1leters for nricro spn

lor gia't sprinkterJffi;;;,frint t.r, ft""t "i'pical

thron of l5 nreters'

Sprinkler

Riser

Laterat Ground Lerel

The raclius of wetted area (11) in nreters can be calctrlated using the tbllot'ing trirrnrula:

R: 1.35 {d. hWhere..i= ii"*""r of nozzle (m) and-

il= G-.* head at nozzle (m)

2.6.2 Water Distribution and Overlapping of the Sprinklers

l'l:,,iffi ''J#'#,i:::i;1,:il:l[:i"il::'ilffi '-::l:'fi:'n':'fr i:':i:ff ll'ol- tlre circles'

utti l irrttt.

the cclge

- - - - \. / -

- :/ ' \

\ - /\ - . /- - - - -

- - - /

W"ttingl'Jtttn for a single sprinkler

\\t

tI

//

Radius "f I tt-'l$l

l 0

ManualSprinkle lrrrigationPractical Applications

Side view

Because ol ' the varyittg clegree of application mte, the distr ibul i .n pat.te*rs sl*rulr lbe overlapped to get the tttoi" ui less, uni'for. pr*nifiiuiion, [.or goeid ulilb''ity rlrr:overlap should be at least 55 - 65% of the wetted clianreter. 'l 'his cletermines rhemaxinrum spacing between sprinklers. To achieve an ac'ceptabte level of distr.i6uti.rrtrnilbrmity there must be sulficient overlap of distribution pattern frorn the acl.iacc'tsprinklers.

I

: 6.3 Application rateThe average rate at whiclr water is appliecl fiorn the sprinklers is calleil ar;' "plication rate. T-his is tneasured in mnr/hour. T'lr" application raie clepen4s on rlre sizc: sprinkler nozzles, the operating presslrre ancl the distance between sprinklers. w6ilt:* ecting a sprinkler.ty:tll it is important to make sure tlrat the average applicatiorr r.ate' less tlralr the basic infiltration rnte of the soil. fhis vvill avoid surlace runoll-arrcl-, ssihle soi l erosion.

l l

llectangular PositioningDiagonnl Spacing

ManualSprinkle lrrigationPractical APPlications

Application rate (Ar) is calculated by the folrlula as below:

Ar :q / (SsXSl ) * 1000

Where,Ss= Spacing between sprinklers (m)

S[ = Spacing between laterals (nt)

Q = Discharge of one sprinkler m3/ht

2.6.4 Drop size o[ PreciPitation

As water sprays from a sprinkler it breaks up ittto snrall drops between 0'5 and

4.0 rrrnr in size. nt a-[iven pr"rr.rr" droplet size increases with nozzle dianreter' And lirr

a given pozzle, cfi:oplet size incrcases asthe pressure hcacl clrops' The srnall drops lirll

close to the sprinkler whereas the larger or,.* ftll close to tire edge of the wetted cifcle'

Largedrops pan damage delicate 9r9ps and soils' ln such conditions it is best to usc tlre

smaller sprinklers. In Jrder to avoid ttop "no

soil.damage it is recommended to use small

diameter nozzles operating at or above the nornral recontnrended operating pressure'

Coarseness Index tCU it,it"O to evaluate the t'ileness of the spray' Higher the value of

cl. finer the spray will be. cI depends on the appliecl pressure and the diarneter of the

sprinkler nozzle.

2.6.5 Operating Pressure

Distributio' uniformity is greatly influenccd by the operating.pressur€ of the

,printrJrr,;;it i; normally .p".in.J Uy ttre matrufaciurer' Substantial deviation 'ft'onr

the reconrntended pressure values ,un ,"r,ilt into gxrr unit'orrnity 6f water distribution'

ll-pressure is too low. the wetted diameter is reduced resulting into the forlttation

ol'excessive larger droplets. This is because; at the lower pressure than recommenclecl tlte

rvater dro;rlets clo not break. On the other hand if the pressure is too high' finer droplets

are lbrntecl tfiat are very much prone to the excessive wind drift and evaporation' ln

either case the uniforrnity of water application is impaired even if the sprinklers are

correctly sPaced.

t2

I

ManualSprinkle lrrigationPractical Applications

3. lrr igatiorr Efl iciency

For any irrigation systenl, tlre unilirrmity ancl efliciency of water application areol- nra.ior interest. Not ali water taken lronr the source reaches root zone of the plants"l'here are unavoidable losses of rvater tluring the cou$e of transportation. tlrrouglr carralsand in the field. i-he ternl lrrigation EIficiency is used to express the percentage of watcreil'ectively used by plants out ol'the total water extracted.

Irrigation efficiency of the systenr (e) is sub-dividetl into:- l-lrd cdnveyance el'ficierrcy (ec) to represent the water transportation efliciencv

arrd- -lhe

application efficiency (ea) to represent the water application efficiency inthe fielde = (ec X ea)/ 100The application efficiency mainly depends on the irrigation rnethods. lrr a

prroperly managed system, the indicative values of application efficiencies of surlace.sprinkler and drip irrigations methods are 600/o,75o/o and 90%o respectively. A sy'sterrruith irrigation efficiency between 50-60 %o is generally regarded as good.

Generally speaking, the application efficiency, Ea, is expressed by the fbllowingequation;

Ea: (Ws/W| X 100Where,Ws: water stored in the soil root zone during the irrigationWf : water delivered tot he famr-fhe

common sources of water losses in the farm arc- Surface runoff lRfJ and- Deep percolation losses (Df)Thus.Wf=Ws+Rf+D fTherefore.Ea: (Ws) I (Ws * tril'j, Df) x ltiOIn the case of sprinkler irrigation. nainly the following factors influence tlte

aFf I ication el liciency.a) Losses due to non-uniftrrrnity of application, rvhich in turu depends ott thc

*racing between sprinklers, operating pressureb) Deep percolationc) Spray drift due to wind rrtovementd) Evaporatione) Pipe leakagef; Discharge rate of sprinklersg) Water retentian in the plant {bliageProf.'.lack Keller has proposed the following fornrula to cpurprute the applicatlorr

ertriiciency of sprinkler irrigation, Epa.Epa: DEpa x Re x OeWhere.DEpa: Distribution efficiency 7oRe: effective portion of applied water, in decimalsOe : ratio of water effectively discharged from sprittklers to the total systettt

"ikcfiuarge.

t3

--t-->.

ManualSprinkle lrrightionPractical Applications

t-h. ubo unilbrnrity and adequacy of irrigation

unproductive water loss is caused mainly due to foilowing

as well as losses.

3.1 Water LossesIn a sprinkler system

phenonrena:a) Direct evaporation from droplets; soil surlbce and crop fbliage.b]

!*.t^R R"t"olation below the plant root zone as a result of poor schedyling.c) Drift clue to windd) RunolTfromr the soil surfacec') 1'ransp.iratiotl lrotn the unwanted vegetation including field boarcle,l) Leaks in the system

lrvaporatiorr losses. are insignifiryl during night. Too fine dropletq. in wintlycorrclitiorrs rvill cause high toss'd-ue to drift ,rrouinl",1t. Similarly-, excessive applicatio*can cause rullolf and deep percolation losses. . '

; , 1

j

t4

ManualSprinkb lrrigationPr*tical Applications

f. Brsic Dcslgn Approach of Sprinkler lrrigatior

{.1 krirtion Water Requirenrent

.'tn general, irrigatiorr water requirement is thc atnount of water that must be*rppi"O tothe crop to ensure its lull growth. The water requiririient of the crop nrainlydepends on the climatic factors and crop factors. Evapotranspiration that is almost equalto t|5 eonsumptive use is the main basis for detenni{ting the cfop water requireltteltt.Crop evapotranspiration consists of transpiration by tlre plants attd evaporation trotn tltesoil aind plafrt surface. Besides the water rrquired for clop, an irrigation systenr alsoshould meet other water requirements which is not consumptively used - such asunevoidable losses, special requirements etc. The contribution fronr the rainfall andground water seepage (capillary action, when water table is nea'to the root zune) shouldbe deducted in the calculations.

Hence the general expression of the Gross lrrigatiorr retluirenrent, (GIR) calt begiven as,

GIR = ETc + Lo+ Lr- Retf - Gw

Where,

ETc = Evapotranspiration

Lo = Water Losses

Lr = Leaching Requirertterit

Reff = Effective Rainfall

Gw = Seepage from groutttl water

Evapotranspiration is influenced by crop, climate arrd etherfactors. Crops under,

sunny and hot climate need more water than cloudy and cool clintate. Plt nts requirc,lifferent amounts of water that greatly depends on the growth stage. Generally.

r"ranspiratiotr rate gradually increases as the plant gfows. Ai the fully-grown stage water

need is the highest- Seasonal crops are characterized by the following tbur stages depending on'their

rge and ground cover.a) lnitial Stage: This is the period fronr sowing or transplanting rrntil the

crop covers is about l0 % ofthe ground.b) Crop Development Stagr When crop covers nearly 2/3'dol'the ground.

d) Late season: Ripening and harvesting of the crop is characterized in

this stage.-'Piitential evapotranspiration (ETp) is thS'amburii of watei transpired in a given

rune by a slrort green crop of uniforru height completely shading the ground and fever

drcrt of-water. tt refers to maximum water loss under,prevail,ing climatic conditions.

Poterrtial evapotranspiration can be calculated fronr ex;rerimental pr theoretical

nprhds. Some of the important rnethods of computing Potential evapotranspiration

scribed below.rt Prr Evaporation Method:

A pan is installed and filled with known quantity of water. It is then allowed to

c'nflrporate. The difference between initial and final depths of water in certain period will

grre t5e direct pan evaporation, Epan. To obtain ppterrtial,evapo-transpiration. E'l'p.

t5

ManualSprinkle trr igationf ragtical Applicationvalue of the evaporation, Epan is rnultiplied by a pan coefficiettt, which usually rangesliorn 0.7 to 0.8, dependihg on the types of pan. Mathernatically this can be expressed as"

li'l'P: KPan X EPan

Where.

ETp :

Potential evapotranspiration

Kpan : Pan coefficient (0.7 - 0.8)

Fpan: Pan Evaporation

b) Penman Metl lod:

Penuran lras assumed Radiation and aerodynanric ternrs as influencing frctors ol'evapo-transpiration. He'has combined these factors into the equation, which is expressedAS;

, , ET',, = (Ww .R,,)* (r - w'ly@\Qa - td)|........ .........(,)

Utadiation term * aerodynarnic terml-l'his

Penman equation is the version proposed by J. Doorenbros and W. Pu"itt inl;.A.0. irrigation drainage papr 24.

Where,

E li, = reftrenca clop evapotranspiration in rnnrlday (til crop being short green'

grass).

C' : adjustment factor

W = weighting factor depending on tenrperature and altitude.

. Rn = net radiation expressed in equivalerrt depth of evaporation in mm/dl1"

/(u) = wind function.

(ea-ed) = Vapor pressure deficit in mitlibar.

For best estimates of short period of tirne Perrruan equatioit is regareleci as il

rel iable ntethod.

c) Illnney-C ridd le lVlethod :

T'his method is based on the assumption thar consunlptive use varies'tr,,ithterriperalure. length of day and available moisture.

-lhe lorrnula is expressed as

[ l = . K F

\\,'here.

Li: Morrthly consumptive use in inches

K: enrpirical crop coefficibnt for the month

l;= variable tlrat depends on the day tirne hotrr's artd telnperature-l'his

method is best for periods of orre rnorrih or nrore, luclusiotr ol- clopcoel'ficiertt is the unique feature of Blaney-Criddle tttetltod.

Often the data on potentihl evapotrarrspiration is available fi'ont iherneteorological stations.

l

l 6

ManualSprinkle lrrigationPractical Applications

4.2 General

In tlie dBsign of ainvolved:

sprinkier irrigatinn system. mainly tlre iirllaw,in*1 1;;ui1i, i;",.

a) Size of the pipesb) Capacity of the Fumpc) Selection of the Sprinkler heac{d) h'rigation Scheduling

]-he fbilowirrg input data lvill be requir*d. frr.ilersisrr of a spriilkl,:r svstsa.r.i.a) Lan{: Topographical rnap of"suitahle se*ll 1lv{ap ol'rhs tlontuur SLerrt-,\.!.t ) water souree: Disclrarge, Availalrre head. vrater errariti.c) Clinrate: Ternperature. i{umiditl,_ Rainf'a!1, Sunslrine hr:urs, i}trt,,rq;i j.1l

evapotranspiration, wind veloeity.d) Crop: type, age, and respe'ctive crop coeflicients (Kc)e) Soil type: texture, porosir,v0 Sprhrkler: Types, performanceg) Pipes / Fittings: Types, Frictional Loss charth) Seruice Provider: Availability.of spare parts, installatiol services erc.

{.3 Design Steps:

a. Prepare the layout map af the plot to be iwigated.al Divide the areas into blocksh t Locate the position of the outlets.c t Decide about the type of sprinkler system: permanent or portatrle..r r Decide about the duration of daily irrigation hours.

h- Colculote woter requirement of the plant:-Calculate the reference crop evftpotranspiration (L: t'o). : !t r:ierr he *trlain*rl irllfl

ne nearest nreteorological station.- Obtain Crop Coetfieient (Ke) f,':r the seler:isi.! e rcp qGi.. cri in ag"r6.r*ndl:.i- Calculate Crop Evapu tran-qpri ratr,un (Fi"l' crop ) :

ET crop: ETo X Kc- Calculate Net Irrigation Rer;rniro:in*er{ {.lnet}

Inet: ETo X Ke + [.r '' FtWheLe.Lr: I-.eaching Ret.;uirerrlerl t i{-Js,i ; t l l r chrt ccxrsic{ered irr r{ i* spri l iFiI t" l uri i , , i i { : i . , ; :R: Contribution fi"onr l{ain{all

- Calculate Gross \\rater Requil.c,nl*irt;GIR: ET'o X Ke X Ea i- I-r- R\\,here.Ea = Irrigation Efficieelcy' i..r.,hie ll i,s tlle:

plnxn"larion losses.Ea: 10000i Ks F.""r

\\ here.K*s: Coefficient of rgater storeFle *trf'lcielrcy Erf tlre snilEu: coeflicierrt of s,/ater clistr"itrutislei r.rnircrrrrity ol'sprinlolers

lvlanualSprinkle lrrigationPractical Applications

- Clalculate peak water requirenrent:q nlax = lpcnk X Crop area

lp.,uk iS tlie maxinium value of gross water rcquiretitent during the growing pc'riod..l'lre

lrydraulics ol-the system will be determined on the lrasis of peak water tequirentettt.

c. I)etennine irrigation depth and irrigatiort interr*1.-\,V:rter storige capacity of soil (PAW)

Plant Available water depends on the depth ol'the root zone and water holclirrg

c; rpac i ty o l ' the so i l .PAW=AWXRZ

AW = Available Water tlolding Capacit.v (ttttttinr)117,.: Depth of the root zone of the crop (m )

- (Jross irrigation depth (GlD)(iross lrrigation Depth (mm) = 7o Allorvable depletion X PAW / Ea

' GID: AD X PAW / Ea

Where.AD: Allowable depletion of soil nroisture. which depends on the crop

selsitivity to the moisture urd varies between 30 to 50 % of the field capacity.

Ea : lrrigation Efliciency whiclr usually varies between 70 to 80 'li' lix'

sprinkler irrigation.- lrrigation Interval / Frequency: (F)

F= AD X PAW / ETcrop- Required Application (Gross)

lg=FXETUoP/Ea- Application Rate (Ia)

l a= lg /TaWhere.

' 'fa = Duration of application- Volunte of rvatet 'Applied (V)

V :Ax lai . e .V: Area ol'the Field X application rate

rf" {-'ulculute nunther of sprinklers antl select the size of the noZZIe:- Based on the- soil infiltration rate. skil-re. and available pressure select

appr.1-rriate sprinkler and recommended spacing Sgr.weerl sprinklers. This inforrlrati()ll is

availirtrle on tlre product catalogue of the manu{'actuters.- Calculate the water application rate

Applicatiol ltate: Flow rate of one sprinkler (lpnr)'I{:O/(Area between Sprinklers (se1nt))

- lrroirr iteration process, choose the sprinklct to mcet the following criteria:- Application Rate < Infiltration Ralt:- Distribution Uniformity > 75o./o

- Calculate number of sprinklers and tlreir spircing

e" Cnlcnlnte the size of the Laterals and Sub nruins:Laterals and Sub mains consist of multiple outlets. For estimating the head loss irl

srrcli pipeline. Ilrst the head loss is calculated assurnirrg that all water is carried to the elld

o!, lilre. l'hen, this is multiplied by the loss factor F that rnostly depends on the nunrher ol-

r;ullets. In general practice the value of F is adoptecl as 0'33'

l 8

ManualSprinkle lrrigationPractical Applications

The pipe size of the raterar is determirt"a uffi- --- r ' r- urv rqlvr4r rr utrtst l l l l r le(I uslng lU "/o fUle, WlftCh StateS. "Tlfe

f:t^t:T: :lllf ion,ulong a lateral (head loss and

"r.uuiiirr lhange) must be limitect ts 20ot, o[the predsure heacl of the selected sprinkler.,,

Frictional head loss along.the pip"r cm be computed using well known for,ularor tlre pressure flow regirne.l. Culculote the size of the ltloinline:

- Prepare a flow diagram and indicate the peak flow at different sections fronr thekrrowrr discharges of the emitters.- Calculate the cumulative flow by adding up the flows at different sectio,s- Perlbrm hydraulic calculatiohs using stanclard formula (Darcy weishbacS

Hazan wi l l iarn Fornru la) . \vqrvJ " wr '

. - Make allowances for tlre minor head losses as well.- Determine the pipe sizeg. Calcalote the capacity of the pampset:

'The total power of the punpiet required has to be baserl on the design dischargeanrd total operating head.The total head is the sum of total static heacl of punrping and the fi.ictional losses=:rd rrrininrulrr lread reqr.rired irr the enritters.The Florse r9r1919rthe pump is calculated f.onr the lollowing {brnrula,.p:(eXH) /7sXEWhere,

Q = Discharge in lpsH = Head in MetersE: Efficiency of the motor, usually 0.6 to 0.g

The total discharge is the sum of the sprinklers discharge operating at a tilre. 'l'5is:':retrds on tlte type of sprinkler systeni and characteristics of the spripkler head.

It:.:,,1$gl {Hr) is the sum of head'rosses it trr* pip.s'along trre criticar rineru": the elevation differences. T'he general expression for th.'t[;iil;;,r'L*""niu"n o'F t r - . : [ J , . J L t I t ) : - - - - r r - ! | , . r ,

- - - - - - P '

Where,H,t: Hbrcrot * H nain+ Riser Height * H brut * H.r,rtio, *_ H ,;":"f;,,

or

Hlore,at & Hu,ai, are the frictional headmainline respectively.

Iosses along the lateral ancl the

H roror: Local head losses because of the various fittirrgsHsuction : Head loss in the pipes due to suctiorrH etevarion : Elevation difference

\t eter Distribution UniforrnitvUniformity water distribution to different parts of the crop field is one or'tlre

r'-'r factors that influence the efficiency of the irigation systenr. poor ulifornrity'l*cr.s crop productivity and in turn reduces the farm incorne.

Various formulas ltave been suggested to nreasure the degree of ulilbrmity. T'he'r: conrnlonly used expressions are given below.f hristiansen,s (Jniforntity Coefficient (Cu):

This is the most widely-used parameter, which is given by:I r - t - - - r l

( I = tool r- LL-"| |L l, I

t9

ManualSprinkle lrrigationPractical

Wltere,

z = individual application volume

m = Sunt zl n= mean application volunre

n = No ol'observations

6. Opcfnfiglt arrtl lVlairrtrr;sto,tts<- of tl.e S1+ri-Ll-- l.'-ir+'tidn Swctern

'l'lre lollowing points aIe inportant to retrtentber so as to properly manage a

sprirrkler irrigation system'

a) Always move pipes with great care'

b )Dono tope ra te fas twh i l eopen ingandc lc rs ing theva |vesas t | r i s i nayc rea te

water har'mer eflbct resulting into the dantage rll's1'stenr cottrponents'

c)Clearrt|ref i l tersregularlyasthebtockagecalrreducetlrepressure.

c l ) I tepai r thepoinBof leakagetomainta i r r t l redesi rab leoperat ingpressure lat t t |

Prevent lirim water loss'

e ) l . . r r su re tha tsp r ink le rnbzz lesa re f ree f i r r t t t obs t ruc t i ons ' c lean thenozz le i l "

ittlv clogging is noticed'

l') Storc thc equipnrent in a safe place'

20

ManualSprinkle lrrigationPractical Applications

. . , , .7. Irrigntion Scheduling

7.1 ( , -enera l

Dif{-erent soils irave different capacities to retain,'water. Soil with high porosity.ruclr as sand has poor holding capacity where as, fine textured soils have higher value ofrrater ltolding capacity. Available rnoisture, which is the difference betweelt lleldcapacity and permanent wilting point, is the range at which water is extractecl try then l i r t r ts .

Management allowed depletion (MAD) is the teduction of soil moisturc irrnercetttage fiom tire field capacity before the next irrigation. Tlris allowed depletion leve!'' aries among crops and regions. trn arid and semi arid regions MAD should not treallowed to fall below 50% of the total available water. As a general rule the allowahletttoistttre depletion for drought sensitive and non-sensitive crops are taken as not ntore

| .lian 30% and 6004 respectiveiy. However, in case of high value crops it is o{ierr

| ::olitable to iruigate before 50 9/o of tlre available soil moisture irr the loot zone has lrcerr

l - : p l e ted . " ,

I|

- . t t r r igat ion Depth , .

I l he depth of water that should be applied per irrigation d in mm based on theI

- .rirrrunr allowable deficit MAD can be expressed asI D: (MAD% x Wa xZ) / 100I Where.

I Wa = plant available water. mm/m| 7.: ellective rooting deptli. mI Tlre water holding capacities of various soils are as follows:

I| | S"tl tyI I Coarse Sand I qZ '

III iFi'*loam Flst-----1

li! : rratrvely.

I Net irrigation requirement NIR can be computed fronr the iollowing expressiorr.I NIR: (Mf-Mb)x Db x Z/ t00

I \\'lrere.

I lvll-: Moisture content at filed capacity o/t

I ir{b: Moisture colttent before irrigation oZ

I llb : llulk density of soil, grn/cucmD = . : c ra t .I NIR: (Mt- . Wp) x dm x ZxPl 100f Wiiere.

I dm : rnoisture depletion allowed in percentage

I \\'p: moisture content at wilting pointI P :9/o volume of soil wettedII

Ir2rIL

Soil tvpe Haldine capacitv rnm/mCoarse Sand 42Medium sandy loanr 125Fine loam 183Clay t92

rrual .

Frlrf*e l*riilafiiibnractical Applicdions

eH*rLcsTr( 1,0s6.48)

756wT5(1076.64)

let2.48)

43.?w.

D2(t09s.0e)

\ 2(n33.&I

T4 (1S64.44)

D3(r088.67)

2 IZm

iI

Scl e.rne Plan of proposedSpriirkler Irri gation Project

Source, S (1 150.00),

245m

l l la in ,Ml (1 t35 .35)

l87nOi*tribr*issD t ( r ' l l 0 . t 6 )

Reservoirn R(1. | 25.22)

Dzl(1088.84) I 28nt

T3(t040,48)

29

'16{1062.87)

ManualSprinkle lrrigationPractical

SPrinkler lrrigation Proiect

Reservoir Sizing

Input Data & Basic Galculations .

)TotaLHouseh

)Commanded

) Peak Water c

) Hence, Total

) Minimum inte

Adjusted intal

) Number of ot

) Totalwater v

Opetaring hot

r Discharge Pe

olds

Area @2 RoPani/HH

lemand, per roPani Per daY

water demand for commanc

rke from the source

re from of the source

rtlets

olume per TaP / daY

rrs

r tap- ::harqe of the outlet

Calculation of

area per daY

Reservoir Sizing

201

401

35?2

140880

1 .63

1 .71

6

23480.00

14

0.466

0.45

IH

lopani (2 ha.)

:r

:r

ps

tr

rours

ps

Hours Duration, Hr Flow,lps lnflow. ltr Use. Ltr Balance, L',r

r PM- 4AM c 1 .71 55471.4 c 55471.1

lAM- 12 Noor t 1.7 ' , | 4930€ 7776C 27019.1

12 Noon- 1PM 1 1 .71 61 5€ c 33175.1

1 PM- 7PM € 1 .71 3693€ 5832( 11791 ,

24Hrs

Required Size of the Storage Reservoir

Adopted minimum size of the reservoir

55471 .5ltr' 56000ltr

30

Matrua lSprinkle l rr igat ionPiactical APPlications

Appendix 1: Approximate Duration (Days) of Growth tT::y::=

. . rce .C 'BrouwerandM.Heib taem; l r r iga t ionWatermanegementTra in ingmanua lno .3 . , ' 'i ; i!

appendix 2 : Typic'al roo-ling deplh e[.grops (m)

. T. :i =Ao lmgation and Drcinage Paper No 24' CloP Water Requircments' Table 39

3Ca3C:' l

301 01 52C4t

ps iotal (DaYs)mitialstage (DaYs)SropDrvdoPmcntrteges (DlYl)

s?-te||

/3)

2512525305C

5025603{5t

lBean/green

lBean/drYCabbageCarrot

12075

12010c18(

1 52C

, 2 (3(

3040303C3(

404a60601 l 1

CucumberEggPtantGrain/Smallt ^ n l i l

I

111

.zv

30202A2t

LettuceVaize, Sweet'r4aize, Grain .',.'lelon,,,li l let

Jnion/greenJnion/drY:eanuUGroundnut= e a

103020'25

c

8r12121:O

202Q2a1 t2!

2a3t3t?l3

zc40io'40

1C7L sol

4535403C

1t201309C

1.2C10t

151251 52525

25r3525353C1013030203C

154060153(

,oi25]l

5l151-q2525

3511201356095

202A2C2t

t53l4(

6€454C

1601251 3 5

4

2Q3C

MediumIlecp

Shal low

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ffiplantQ1a1p (smg!t) ".",,Peas

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(I'

ManualSprinkle lrrigation

Practical

Appendix 3 .Head loss chart for HDP pipe (lSl Standard)

32 mrn'----------r':=G i : a 16rnm* 20 mm* | 25 t!!n'

({Okglct4!} (10kg/cm4 loko/cm2) 1Okq/cmz) | bKgl_clMltienes

,lR t| mm 24mm 27mmlnsidediameter 1'!,6 mrn t5 rnm

A (lpsl1 .2 0.4 0.2

0. t 1 ) 6 3 . 1

0.3a12 .t-? F 5 .1 1 .7 u.b

1.95 0.6 0.350 .13 20.25 5.9

6.7 2.2 0.7 0.40 . 1 4 n a

26.1 7.6 2.5 0.8 u.4c0 .15

2.8 0.9 0.50 .16 29"2 8.5

9.45 3 .1 4 u.cco 1 7 32.65 0.6

36.1 10 .4 3.4 1 . 1

39.9 11 .5 3.75 1 .2 0.7

43.7 126 4 .1 1 .3 0.81 .6 0.9

i o.22L' 0225

51 .9 14 .9 4.9

54 1 5 . 5 5 .1 1 . 6 0.91 .70 0.95

n t a 57.35 16.45 5.40

0.24 60.7 1V.4 5.7 1 .8

65.45 1 8 . 7 5 6 . 1 5 1 . 9 31"20.25

0.26o?7

70.2 ?0.1 6.6 2 . 12 .25 1 .3

75.3 21 .55 7.052.4 1 . 4

o ? 8 80.4 23 7.5B 2.55 1 .45

85.75 24.5

0"3 91 .1 26 8.5 2.7 1 .5

45.55 27.6 g 2.85 1 .63 4 ' 7

t - a

0.32 29.2 9.53 0 9 10.05 3.2 1 . 8

32.6 10.6 3.4 1 . 9

0.350.36n ? 7

34.4 11.2 3.55 z

36.2 1 1 . 8 3.7 2 .1

38.05 12.4 3.9 2.?

0.38 39.9 13 4 2.313.6 4.3 2.4

n ? o 418543.8 14.2 4.5

0.41o.42

45.8 14.85 4.7 .b3

47.8 15 .5 4.9 2 .8

dq q5 16.2 5 .1 2.9

0.440.4!0.460.47

52.1 16.9 5.3 .J

54.2 1 7 . 6 5 . 5 3 .1

56.5 18 .3 5.8 3.3

58.75 19.05 o 6.4

_* 6163.35

19 .8 6.2 ? 5

n / tO 20.55 6.45 3.25

. 5 65.7 21.3 6.7 !)

37

ManualSprinkle lrrigation :Piactical APPlications

tu?O mm* 25 mm'101Size 16mm' nLa lam?l

Series,lokolcm2l (1OK$ern4l-

24mm 27mm.15 mm 18.9 mmlnside

diameter 11.6 mm

o (lps_)- 6.95 3.5568 .15 22.O5

22.8o 5 1 J27.45

4 .10.52 70.6 4.25

73 .15 23.650.53 7.7 4.4

4.6jiEI€+.ii"ik riiirh a:

24.50.54 26.1 8.20.56 8.45 4.75

40.45 26.950.57 8.7 4.9

27 .60.58 I 6 . 1

o-59 9.3 5.329.8

0.6 9.65 5.530.75

0.6125 10 _9f6 .1

3 1 . 90.625 34.3 10.70.65 11 .1 6.3

35.50.663 11 .5 6.5

36.70.675 12.3 6.939.2

40.50041.8

0.7 12.700 7 .1500.7130.72!

19J13.9

7.47.8

44.545.8500.75 14 300 8.050

8.38.8

0. /65 47.2 14.70.775 15.6

0.8 16.5 9.3_ i955.90 825 17.4 9:8

10. x000 8 5 57.450 17.90010.40.863 59 18.4

0.875 lg.s I to.g62.10.9 i-gsqo-L---U-q9-

0 .913 20.3 11.412o.9zb 21.3

0.95 21.800 12.3000.0000.9630.975

2E23.4

12.613.25

1 27.8 15.7

32.6 1 U , 4

1 .2 37.8 21.31 .3 " l-:' 4 24.3

nls41 .5 31 .11 . 6 34.7

1 . 7

3B

\lanualSprinkle lrrigationPractical Aoolicatio

Size 40 mm 50 mm

Series {10kqfcm2)(6kolcm2)

(10kqlcm2) (6 kqlcm2)

diameter 30.3 mm 33.7 mm 38 mm 42.2mmo

0.22 0.5 0.30.226 0.5 0.30.26 0.7 0.44.27 0.75 0.450.28 0.8 0.50.29 0.85 0.50.3 0.9 0.5

0.320.33

1 0.6 0,3 o.21 .05 0.65 0.35 0.2

0.34 1 . 1 0.7 0.4 0.20.35 1 .15 0.7 0.4 0.250.36 1 .2 4.7 0.4 0.30.37 1 .25 0.75 0.45 0.30.38 1 .3 0.8 0.5 0.30.39 1 . 4 0.85 0.5 0.30.4 1 .5 0.9 0.5 0.3

0.41 1.55 0.95 0.5 0.34.42 1 .6 1 0.5 0.30.43 1.65 1 0.55 0-350.44 1 . 7 1 0.6 0.40.45. 1 .8 1 . 1 0.6 0.40.46 1 .9 1 . 1 0.6 0.44.47 1 . 9 5 1 . 1 5 0.65 0.40.48 - 1 .2 0.7 0.40.49 2 .1 1 . 2 5 0.7 0.450.5 2.2 1 .3 0.7 0.5

0.51 2.25 1 .35 0.75 0.50.52 2.3 1 .4 0.8 0.50.53 2.4 1.45 0.8 0.50.54 2.5 1 . 5 0.8 0.50.55 2.6 1 . 5 5 0.85 0.50.56 2.7 1 . 6 0.9 0.50.57 2.75 1.65 0.95 0.550.58 2.8 1 .7 1 0.60.59 2.9 1 .75 'l 0.60.6 3 1 .8 1 0.6

0.6125 3 .1 1 . 8 5 1.05 0.65

0.625 3.2 1 . 9 1 . 1 0.70,65 3.5 2J 1 .2 0.7

0 6625 3.6 2 ,15 1 .25 a.750.675 3.7 2.2 1 .3 0.8

0.7 4 2.4 1 .3 0.8a.7125 4.1 2.45 '1.35 0.85

39

ManualSprinkle lrrigationPractical Applications

Pipe sizes marked * are very sensitive toplight crranges in internaldiameterHeadloss figures colored yellow are for fl6ws where the

40

o.725 4.2 2,5 1 . 4 0.90.75 4.5 2.7 1 .5 0.9

0.7625 4.65 2.8 1 .55 0.950.775 1.8 2.9 1 .6 1

0.8 5 3 1 .7 10.612F 5.15 3.1 1 .75 1.050.825 5.3 3.2 1 .8 1 .10.85 5.6 3.4 1 . 9 1 . 1

0.8625 5.75 3.45 1.95 1 .150.875 5.9 3.5 2 1 .2

0.9 6.2 3.7 2 .1 1 .30.9125 6.35 3.8 2 .15 1 .30.925 6.5 3.9 2.2 1 .30.96 6.9 4 .1 2.3 1 . 4

0.9625 7.05 4.2 2.35 1 .450.975 7.2 4.3 2.4 1 .5

1 7.5 4.5 2.5 1 .51 .1 I 5.3 3 1 . 81 .2 . 10.5 6.3 3.5 2 .11 .3 12.',| 7.2 4 2.41 .4 13.9 8.3 4.6 2.81-5 15.7 9.4 5.2 3.21 .6 17.7 10 .5 5.9 3 .51 . 7 19 .8 11 .8 6.6 3.91 . 8 21 .9 13 .1 7.3 4.41 . 9 24.2 14.4 8 4.8

2 26.6 1s.8 8.8 5.32 .1 29.1 17.3 9.6 5.82.2 31 .7* " 18.8 10 .5 6.32.3 34.4*"* 20.4 11.4 6.82.4 37.2"' 22.1 12.3 7.42.5 44.1'** 23.8 ',3.2 7.92.6 25.6 14.2 8.52.7 27.4"" - 't5.2 9 .12.8 29.3" 16.3 9.82.9 31.3"* 17.4 10.4

3 33.3"* 1 8 . 5 11.13.1 19.6 1 1 . 832 20.8 12.5.3.3 22 13.23.4 23.3 13.93.5 14.73.6 15 .53.7 16.33.8 17.13 .9 17.9

A 18.84.2 20.5'*'4.4 22.4"',

Reynolds number is below 10000

ManualSprinkle lrrigationPracticalHeadloss figures marked*"'& corored blue are for flows where tne neynoiGnumber is above 40,000 i.e. where velocity of flow is greater than 3m/s

Gl Fric4 tion: Head loss Factors

Flow {LPSI112GI 1 " G l

?

11 t2* G l 2" Gl 3" Gl0 .1 5.87 0.38

0 .15 12.24 0.820.2 21.43 1 .33 0.2

0.225 26.53 1.68 0.220.25 31.63 2.04 0.240.3 44.9 2.96 0.4

0.35 58.1 5 3,82 0.520.4 74.49 4.79 0.66 0.22

0.45 91.84 6.02 0.83 0.270.5 7 . 1 4 1.02 0.33

0.55 8.67 1 .19 0.390.6 10.2 1.43 0.46

0.65 11.73 1.63 0.530.675 12.76 1.68 0.55

0.7 13.27 1 .73 0.580.75 15 .31 2 . 1 4 0.670.8 17.35 2.35 0.77

0.85 18.88 2.65 0.870.9 21.43 2.86 0.92

0.95 23.47 3.27 1.021 25.51 3.57 1 . 1 2

1 . 0 5 29.39 3.83 1.221 .1 30.61 4 . 1 8 1 .33

1 . 1 5 34.69 4.59 1.481 .2 35.71 4.92 1 .581 .3 40.82 5.71 1 . 8 4 0.221 .4 47.96 6.63 2 .14 0.261 .5 54.08 7.55 2.45 0.281.6 61.22 8.47 2.65 0.321 . 7 67.35 9.49 3.06 0.351 . 8 76.53 10 .51 3.47 0.411 .9 11.73 3.78 0.43

2 12.76 4.08 0.492.2 15 .31 4.9 0.572.4 17.86 5.71 0.662.6 20.41 6.63 0.812.8 24.49 7.65 0.92

3 26.53 8.67 1.023.2 29.59 9.69 1 .123.4 33.67 10.92 1 .323.6 37.76 12.24 1 . 4 33.8 40.82 13.27 1 . 5 8

4 45.92 14.79 1 .734.5 56.12 17.86 2.09

21.43 2.555.5 26.53 3.06

6 30.61 3.67

41

Manual

3571 I 4 1 8Practlcal fll l

I6 .5 40.82 4.85

7

le lrrigation

AppendixS:Valuesof theCropFactor(Kc) forVar ioust -O"t "O: t "* tn t t "n" :

Source. C. Brouwer and M' Heibloem: lrrigatiott Water matrrgement Training manualno' 3'"

"lrrigation Water needs"

Appendix Available Water of Typical Soils (rnnr/nt)

42

Late seasonlnitial stage , GroP Mid- season

Crop 1 .151 .11 .11 .051 .15

0.450.90.30.90.75

0.350.350.350.450.45

0.750.70.70.750.75

3arleY/OatslUVneat

Bean, green

Bean, drY

Cabbage/CarrotCotton/flax 0.75

0.80.650.50.9

0.450.450.350.450.45

0.70.750;750.750.6

u.v1 . 1 51 . 11 . 11

jucumber/Squash

Eggplant/TomatoGrain/Smallt l 'ntil/Pulses

1 . 1 51 . 1 5

11 . 11

10.70.750.65

1

-ettuce/Dpll lat''

vlaize, sweet

Vlaize, Grain

VlelonMilletonion. qreen

oZ I o'80.4 I 080.45 | o'zs0 .35 I 0705 I 0 .7

0.85a.71.050.9 ,0.85

-0.75

0.750.8o.70.75

1 . U C

1 .051 .151 .051 .15

Cnion/drYPeanuUGroundnutPea, fresh

PepPer, fresh

u.c0.40.450.350.45 0.e I

1 '1 11 . 11 . 1 51 . 1 51 . 1

0.90.650.60.80.550.9

iHotato0.450.350.350.450.350.35

0.60.750.750 .80.750.75

RadishSorghumSoybeanSugar beet

lSunflowerlTobacco

E-*tto"tublt Wntt'Available Water

Siltv Loattr

ManualSprinkle lrrigationFi""til"'iiipfiGiion' :

--

bs determined bY:.[heirrtervalbetweentwosuccessiveirrigationscan.pr.slglrrrl:Nv'9

lP = lg/ ETWhereoIp = lrrigation Period' drYs

lg = .Gross aniount of watc1P,er irrigation' nrm

dT = ContumPtive usc' am/day

22

' , ' anua l

Sprinkle lrrigationI nactical APP|lcatlons

s.PREASSEMBLEDMICIT0-S|,RINKLERIRRtGA'r loN(PMl)

\ . I Genern l :

olf-seasou vegetable farnting can be a good source o[ incoure lbr small {-artriers'

,.1icro Spri'kle lrigatio. (PMI) i, tit"pf., loi cost.a'cl suitable lbr irrigating closecl

- , . r . ' v i t t gc rops (c rops t l . r a ta re .g row l r c l ose l y ) suc l r asga r l i c , o t t i o t r . sp i nacha r l c i- ,riancler. Micro Sprinkle in'igation i, troionry suitable lbr 1ilain lancl but il.:un be usecl

rlie sloping terrain- Micro slri'kler can be efficie'tly ,-,r",i i" the areas with t6e soil ol'

-,.or nrater holdi'g capacity. T'he cottventio'al irrigatio' system is not suitable for suclt

- ,nditions, as it can "uur.

soil erosiotr and require huge iluantity of water to t"'.'eet the

." \n water requirement.\.1 \ l icro Sprinkler (MS) Irr igation System

As in the case of any otlt.|. irriiatiorr-ryr,"nt. this systenr also consist a reliable

:i ,.r!ce of warer. Apart from the "n,lu"y?rr".

-"diuror, tl'rat.can.o" I.ry:::.."pen

chantrel

conbination of both with reservoir this systern consists trausmission pipes' flow

....rlating devices, u nta", prior to tl-re MS head to clean sedimeuts aud MS heads to

*::3rate fine spray of *ut"i. The operating head of the micro sprir-rkler ranges between

t "l:::,i;"r to any otrrer sprinkrer,.ricro sprinkler irrigates i'trre toltl:,t',roray. likc,

.-.r l l with uniform distr ibution. ' Ihis f ine spray minimizes soil cornpaction' Micro

i: - :rkler is snraller version of sprinkler, which operates- ou tlruch less head altd florv than

, .,. rrl spri.kler 1i5 meters). Likewisb, the radius of throw of a micro-sprinkler is also

, ..:iely snrall. Because of these technical characteristics, micro-sprinklers are

, "" 'i 'r'iate for irrigating crops itt trarrow plots'

: ,re otlter l'eatr-rres of the tecltnology are:. I t i s l owcos t ,a f fo rdab le tos r r ta l l r u ra l f a rn re rs .' 1t is easy to install, operate aud rnaintain'. lt is easy to change the position oi *irro-rprinklers to reach aty part of t5e la'd

io be irrigated.., Because of builrin filter in the system, the sprinkler head does trot get cloggecl'

rl-':' -asic site conditions for micro sprinkler irrigation:

. Required pressure 6eacl range: Mi.imum 10 rneters' attcl optinrunr l5 I "eters

' Requirecl water discharge range: 0.10 to 0'20 lps (average discfiarge ol]a hal[- inclt

.rze public tap).' \{ininturn land arca:2 Anttit (- 60 Sq' m)

r \rea Irot alfectecl try high rvirrd velocity'

3t n&*n courPonents\ :,,"utplete Package of N'[icro-

rprirelr;ler system has following

nur.5

\(ain Pipe Line

: fuser I ' iPe

] 3as€

+ loe

5 lou-k

ln.liru: f ilter

tlS I lt,il

ManualSprinkle lrrigationPractical APPlicatior

6. Stake

7. ln-l ine Fi l '

8. MS Head

System Sizes, CoMicro-sPr

irrigation coveral

IS

;er

st and Area Coveragei"kil is availabl" i",, t*o differefit sizes - small ar

1e and retail prices are as follows'

:rd large. 'l'heir

I rrigation Area Coverage No of MS heatls Ilrice l(sSvstern Size

4 Rs 125 [ruSmall 250 Sq m - 500 Sqm

8 Rs. 1130. 00Large 500 Sq. m - 1000 Sqtn

@w of the Micro-sprinkrer rrr igation sy

<-- K;?;ig (,9"?r)Aui qdtr

(9t' ,,.1zr.rJzr.) ^,E", fuv.ze

,/

{-----I

+Qa xau fra:5^era

v {->rze

i i777qz4 r.17

fur;etr t A' I

24

ManualSprinkle lrrigationPractical Applications

9. lnstalla{ion and operation of the systemS\rroe the s5stesr rs is. pre-asserrrh(ed. totrn, iK instattatran is simple.

-[he basic steps of

installation and operation are as follows:

a) Open the system and read the instructions carefully'

b) Fix the last Riser set about 3 meters from the edge of the crop field.

c) Fix the other Riser sets in sequence towards the in-line filter.

cl) With Gate valve closed, connect the pipe end with the pressurized water source.

e) Open the Gate Valve slowly ancl irrigatef) Aftefadequate irrigation, move the Riser set 3 - sideways.

W

' )<. J

Sprinkle lrrigatiortPractical Applications

10. Pk "ttrrg

a1d lmplementation of the sprinklcr lrrigation system'

llroper planning plays an intportant role for successful operation and tttanagetttettt

of the Sprinkler trrigaiion System. Ip Nepal. the inigatiop policy demands. participatiop

li.o'r the users. In such contixt'the pto."rr of the development of,the sprinkler irrigatiorl

project has to undergo through the following rnain stages'

Stage 1: Resource I'nventorY StudY:'fhis process esseptiaily inclides obtaining inlbrmation ort the physical resources.

socio-econouric context and market environment. A resource trtapping is prcpared as it

par.t of this study. Ihe following checklist can be usetl to gather this inforrnation.

A : Socio-economic infor:rnation :total householdslurain occupationaverage fann sizeland tenureproposed commanded area'Labour availability and seasonal variationcurreut irrigation practicesLand:topographysize / shape of the landsoil type (surface and sub-surface texture of tlre soil)

water lnfiltration rate

Crop:existing croppillg patternI'easibility f* ftigft vdlue crop (climate. input /or-r'tput market, agtouorttic

services and infiorrnation)

Wnter:Water Source typeWater right issueDischarge at winter and spring seasonsAvailable headAvailability and suitability of land for structures ('fank, lntake etc) '

Water Quality

Ilnvir.onnrcrrtal / Policy Aspect:Need lor E,lA/ IEEl)ublic opinionsWtrter Policies / Laws

F: Market :- Nearest Market and distzurce from village- Ease of equipnrent supply (market chain)- Market 1or produce (vegetable, fruits)

Stnge 2: Social Preparation / Users Group'forurntionColduct village meeting for the need idetrtification/ rvillingness

- Discuss about community participation dr"rring the project- Contribution to the project by the community

t ) ,

C:

E:

26

knualSprinkle lrrigation

- Fornration ofusers grouP' ' . 'Fstelat ia l iwater 'sources: ' ' .

.' Water'distribution asPects:

' ' ! ' '

' : ' ' : " I

rd Cost EstirnrtionStege 3: Detail Engineering Suruey al

Sr4e 4: Materials / Equipment'I'rocurement

grga 5: Construction / Testing

$l4e 6: Commissioning / Handover :

S*r 7: Management, Operation and nraintenlnse

ManualSprinkle lrrigationPractical Appfications

l l. Design eoDesrgn Example ior tlFs'Gersysem o,f a Communify Sprin{cler }rrigation SysremA village at Gorklra distric! near Gorklr a bazaar cofsists of 2a households. Eacfrhousehold ltas more thut 2 R.opani of upJarrd n"* l,oru"**d. i spr.hrg water source, owrre6 bythe comntunity is located at a distalce of about I km fronr the viilage. Ttre vertical heightdifference between tlre soutce and' the'village is approxirnatety llsnretres. Tlre nreasureddischarge of tire water source during May is 2.2'ri ':;sr,,"""il. '"' '

t ' Jtrrslrss' I rrc

Each household of the communiU-are willing to gro* ;l; a'd oniorr during winter andspring s€ason in two Ropani tarrd area.

The crop coefficients (kc) for above crops at different stages as per FAo guidelines are as below.

The B0 %months as obtairred

reliable rainfalf and daily poterrtial evapotranspirationf,rom the nearest rnetedrological statiou is as under

(ETo) for various

Assume- (a) one outret is strfficient to dis*ibute water for 4 to d househofds.(b) The cumulative tap dischage with double tap: g-4U ,Ur.soil t-vpe is mediunr / roanry witrr the foHiwing varues of water. hor.ding-- Available water 60_l20,mm/m of soil- Allowable moisture dep.fetion 3,0yo betow the Fielcl CapacityI{ootirrg Depths: Cabbage= 0.a5 rn Onion:0.3 nr

Ctlculate:a) croP water reqtlirenrent and lrrigatiotr requirement under sprinkler irrigatio' system.b) Size ol'the Water storage Reservoirc ) llescn,oir. operating schiduled) Pipc sizes in all pait of the rretworke) lrrigatiolr frequencyNu{e:E t c = E t o X K c

rainfall nrnr

28