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GE 506 IRRIG TION
GE 506 IRRIG TION
ENGINEERINGNGINEERING
Course Lecturer: Dr J.K. AdewumiCourse Lecturer: Dr J.K.
Adewumi
Dept. of Agricultural EngineeringDept. of Agricultural
Engineering
UNAAB. NigeriaUNAAB. Nigeria
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Methods of Irrigation
ethods of Irrigation
A. A. Surface rrigationSurface rrigation !ild
flooding!ild flooding
Border stripBorder strip
C"ec# BasinC"ec# Basin
$urrow$urrow
B.B. Su%& rrigationSu%& rrigation
Natural su%&irrigation 'Ad(antages ) disad(antages*Natural
su%&irrigation 'Ad(antages ) disad(antages* Artificial
su%&irrigation 'Ad(antages ) disad(antages* Artificial
su%&irrigation 'Ad(antages ) disad(antages*
C.C. +(er"ead rrigation+(er"ead rrigation ,otating "ead
s-stems,otating "ead s-stems
erforated pipe s-stemerforated pipe s-stem
$urrow irrigation$urrow irrigation
D.D. Border rrigationBorder rrigation Le(el Border Le(el
Border
/raded Border /raded Border
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Water Measurement in Open
ater Measurement in Open
channel
hannel
!ater measurement in pipes!ater measurement in pipes
0olume0olume
0elocit-0elocit-
+rifices+rifices
Basin $low E1uationsBasin $low E1uations
2-draulic ,adius2-draulic ,adius
Continuit- E1uationContinuit- E1uation
Darc-&!ei%ac" E1uationDarc-&!ei%ac" E1uation
Bernoullis E1uationBernoullis E1uation
hY W
P
g
V Y
W
P
g
V +++=++
1
2
2
2
1
1
2
1
22
gd
flvh L
2
2
=
QV AV A == 2211
P
A R =
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Measurement of Irrigation Water
easurement of Irrigation Water
Buc#et and watc" met"odBuc#et and watc" met"od
$loat met"od$loat met"od
$low from a (ertical pipe$low from a (ertical pipe
$low from a "ori3ontal pipe$low from a "ori3ontal pipe
Disc"arge from sip"on tu%esDisc"arge from sip"on tu%es
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re!uenc" and mount of
re!uenc" and mount of
Irrigation
rrigation
4et"ods of $re1uenc-4et"ods of $re1uenc-5 4eteorological 4et"od
for determining CU or E6p for t"e plant4eteorological 4et"od for
determining CU or E6p for t"e plant
Blane- Criddle met"odBlane- Criddle met"od5 lant nde7 met"odlant
nde7 met"od
'i* Crop itself 'i* Crop itself
'ii* indicator lant'ii* indicator lant
'iii* c"ange in lea(e colour 'iii* c"ange in lea(e
colour
'i(* "-siological nde7'i(* "-siological nde75 Soil nde7
met"odSoil nde7 met"od
'i* 4oisture content'i* 4oisture content
'ii* Soil potential %- tensiometer 'ii* Soil potential %-
tensiometer
4et"ods of determining amount of irrigation4et"ods of
determining amount of irrigation
'8*'8* 6ensiometer 6ensiometer '9*'9* C.U.C.U.
'*'* A(aila%le water moisture A(aila%le water
moisture
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Irrigation Efficiencies
rrigation Efficiencies
,eser(oir Storage Efficienc-,eser(oir Storage
Efficienc-
Er ; !s>?@Er ; !s>?@ !s ; amount of water directed@
!so ; amount of water stored!s ; amount of water directed@ !so ;
amount of water stored
!ater con(e-ance Efficienc-!ater con(e-ance Efficienc- Ec;
!f>?Ec; !f>?@ !f ; amount of water deli(ered into farm@ !r ;
water di(erted from reser(oir @ !f ; amount of water deli(ered
into farm@ !r ; water di(erted from reser(oir
!ater application Efficienc-!ater application Efficienc- Ea ;
!st>? !"ere !st ; water stored in root 3one @Ea ; !st>? !"ere
!st ; water stored in root 3one @
+(erall rrigation Efficienc-+(erall rrigation Efficienc- Ei ; Er
= Ec = Ea '8>>?* or Ei ; Er
!ater distri%ution Efficienc-!ater distri%ution Efficienc- Ed ;
8 Ed ; 8 -
- w"ere d ; a(e. dept" of water stored along run during
irrigation@ -; a(e. numerical de(iation fromw"ere d ; a(e. dept" of
water stored along run during irrigation@ -; a(e. numerical
de(iation from
dd
dd
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#esign of $prin%ler s"stem
esign of $prin%ler s"stem
6"e following s"ould %e considered for design:6"e following
s"ould %e considered for design: Area of land Area of
land
Consumpti(e use of cropConsumpti(e use of crop
!ater "olding capacit-!ater "olding capacit-
,oot 3one dept",oot 3one dept"
Effecti(e rainfallEffecti(e rainfall
!ater application efficienc-!ater application efficienc-
Antecedent moisture content Antecedent moisture
content
Net irrigation re1uirementNet irrigation re1uirement
/ross irrigation re1uirement/ross irrigation re1uirement
rrigation fre1uenc-rrigation fre1uenc-
4a7imum time needed to appl- dg '"rs*4a7imum time needed to
appl- dg '"rs*
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&ualit" of irrigation 'ater
ualit" of irrigation 'ater
Depends on amount and #ind of salt presentDepends on amount and
#ind of salt present
6otal salt concentration6otal salt concentration
,elati(e proportion,elati(e proportion
Bicar%onate and %oron contentsBicar%onate and %oron contents
Suita%ilit- of irrigation water can %e e7pressed as S! ;
f'SCD*Suita%ilit- of irrigation water can %e e7pressed as S! ;
f'SCD*
!"ere ; 1ualit- of irrigation water !"ere ; 1ualit-
of irrigation water
S ; soil t-peS ; soil t-pe
; salt tolerance c"aracteristics of t"e plant ; salt
tolerance c"aracteristics of t"e plant
C ; climateC ; climate
D; drainage c"aracteristics of t"e soilD; drainage
c"aracteristics of t"e soil
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#rainage of gricultural land
rainage of gricultural land
Effects of poor drainage on plants and soilEffects of poor
drainage on plants and soil
,educes aeration in soil,educes aeration in soil
!ater&logging!ater&logging
Anaero%ic decomposition Anaero%ic decomposition
6emperature fluctuation in soil6emperature fluctuation in
soil
$actors affecting rate of flow into drains$actors affecting rate
of flow into drains
Soil permea%ilit-Soil permea%ilit-
Dept" of soilDept" of soil
Drain spacingDrain spacing
Drain openingDrain opening
Drain diameter Drain diameter
Distri%ution of potential at a flow %oundar-Distri%ution of
potential at a flow %oundar-
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actors affecting erosion (" 'ater
actors affecting erosion (" 'ater
Climatic factorsClimatic factors
Soil c"aracteristicsSoil c"aracteristics6opograp"-6opograp"-
0egetation0egetation
"ases of erosion"ases of erosion
Detac"mentDetac"ment
6ransportation6ransportation
DepositionDeposition
6-pes of soil mo(ement %- wind6-pes of soil mo(ement %- wind
SuspensionSuspension
SaltationSaltation
Surface creepSurface creep
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Gull" Erosion
ull" Erosion
Aim of /ull- Erosion Control Aim of /ull- Erosion
Control
6o reduce pea# flow rate6o reduce pea# flow rate6o pro(ide
sta%le c"annel6o pro(ide sta%le c"annel
,unoff reduction,unoff reduction
0egetati(e control0egetati(e control
StructuresStructures
Stages of /ull- De(elopmentStages of /ull- De(elopment
C"annel erosion %- downward scour of topsoilC"annel erosion %-
downward scour of topsoilUpstream mo(ement of gull- "eadUpstream
mo(ement of gull- "ead
2ealing stage2ealing stage
Sta%ili3ation of gull-Sta%ili3ation of gull-
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Terraces
erraces
6erracing: An erosion control met"od6erracing: An erosion
control met"od
6-pes are:6-pes are:Benc" terraceBenc" terrace
Broad %ased terraceBroad %ased terrace
Functions of terracesFunctions of terraces
6o decrease lengt" of "ill&side slope6o decrease lengt" of
"ill&side slope
6o remo(e or retain runoff rate in area of inade1uate rainfall6o
remo(e or retain runoff rate in area of inade1uate rainfall
Terrace Design involvesTerrace Design involves:: roper
spacingroper spacing
Location of terracesLocation of terraces
Design of c"annel wit" suita%le capacit-Design of c"annel wit"
suita%le capacit-
De(elopment of farma%le cross§ionDe(elopment of farma%le
cross§ion
Terrace Spacing LocationTerrace Spacing Location
Land slopeLand slope
Soil conditionSoil condition
roposed land useroposed land use $arm roads$arm roads
$ences and outlet$ences and outlet
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#rainage and Reclamation
rainage and Reclamation
rocess and practice in(ol(ed in %ringing saline and al#ali soils
into producti(e conditionrocess and practice in(ol(ed in %ringing
saline and al#ali soils into producti(e condition
Essentials of reclamation procedures:Essentials of reclamation
procedures:Determine nature of t"e soilDetermine nature of t"e
soil
Degree of salinit- or al#alinit-Degree of salinit- or
al#alinit-
Drainage C"aracteristicsDrainage C"aracteristics
6opograp"- of t"e land6opograp"- of t"e land
resence of "ardpanresence of "ardpan
,eclamation rocedure,eclamation rocedureermanent
reclamationermanent reclamation
Lowering water ta%le 'if "ig"*Lowering water ta%le 'if "ig"*
mpro(ing infiltration rate of soilmpro(ing infiltration rate of
soil
Leac"ing of salts in saline soilsLeac"ing of salts in saline
soils
,eplacing e7cessi(e e7c"angea%le Na %- ca salts,eplacing
e7cessi(e e7c"angea%le Na %- ca salts
Suita%le management practiceSuita%le management practice
6emporar- reclamation6emporar- reclamation
,emo(ing t"e salts crust from surface of soil
'Biological*,emo(ing t"e salts crust from surface of soil
'Biological*
loug"ing salt surface&crust '"-sical*loug"ing salt
surface&crust '"-sical*
Neutrali3ing effects of salts 'C"emical*Neutrali3ing effects of
salts 'C"emical*
S-nergic effectsS-nergic effects
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)lass pro*ects
lass pro*ects
8.8. Design a c"annel of rectangular cross§ion to carr-
water at t"e rate of >.m.m
