ASSESSING IRRIGATION
CONVEYANCE LOSSES:
CASE STUDIES OF AHERO & BURA
IRRIGATION SCHEMES
A COLLABORATIVE RESEARCH PROJECT BETWEEN NIB AND UON
By
Gichuki F., Maina D., S. M. Muturi and Wanjogu R. K.
1
Date: 13th JUNE 2013
Ahero, Bura and Mwea Irrigation Schemes case studies
PRESENTATION OUTLINE
Introduction
 Objectives
 Methodology
 Research results
 Acknowledgements

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AIS & BIS water loss study-NIB & UON
INTRODUCTION

Irrigation in Kenya faces serious challenges which have
negatively affected the productivity, profitability and
sustainability of most irrigation schemes. The following
is a partial listing of the main challenges
High pumping costs;
 High levels of siltation; unpredictable flooding & drought
 High conveyance and application losses;
 High mismatch between water demand and supply;
 Inadequate drainage of excess water and removal of excess
salts; and
 Inequity in water delivery in different irrigation blocks and
irrigated fields.
 Inadequate irrigation skills among farmers and other
stakeholders
Source: NIB Strategic Plan 2008-2012

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NIBS STRATEGIC DECISIONS
 NIB
has prioritized research on irrigation water
loss and has consequently included it as a global
PC target FY 2012/13. This is a logical step in any
water management improvement initiative
 Cognizant of these challenges, NIB + UON –
College of Architecture and Engineering have
developed a comprehensive research program to
improve performance of irrigated agriculture
through better irrigation water management.
 Phase I of the research will focus on water
conveyance losses
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GOALS OF NIB-UON RESEARCH COLLABORATION
Specific goal
Rationale
Reduced water loss Reducing water loss will secure water for expansion of
irrigated area, enhancing equitable distribution,
reduce operation and maintenance costs and avail
water for downstream users
AIS & BIS water loss study-NIB & UON
Enhance equitable Enhancing equitable water distribution will reduce
water distribution water use conflicts and enhance payment of operation
and maintenance fees
Reduce operation
and maintenance
costs
Enhance
production
and
profitability
Reduce
environmental
degradation
Reducing costs will enhance recovery of operation and
maintenance fees
Enhanced production and profitability will enhance
poverty reduction outcomes of irrigated agriculture
Enhance sustainability through reduced in-scheme
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land and water degradation and by securing water
for
downstream ecosystems.
RATIONALE FOR CONVEYANCE SYSTEM RESEARCH:
Low
 Scheme
AIS & BIS water loss study-NIB & UON
efficiency (30-70%) of conveyance
and distribution system with major
implications on:
water intake sub-system
 Operation and maintenance of conveyance
sub-system
 On-farm sub-system
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OBJECTIVES
Overall goal:
 To generate and enhance utilization of data,
information and knowledge on irrigation water
management in ways that promote innovation and
effective and efficient utilization of the resources.
Specific objectives
 To quantify conveyance and distribution water losses
in Ahero, Bura and Mwea Irrigation Schemes
 Formulate strategies and plans for performance
improvements
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KEY ISSUES THAT WILL ADDRESSED
1.
2.
4.
5.
6.
7.
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3.
Assess performance and opportunities and constraints for
improving performance;
Identify innovative solutions that will enhance the
performance of the water delivery and water application
sub-systems;
Evaluate technical performance of the innovative solutions;
Evaluate costs and benefits of performance improvements;
Formulate strategies and plans for performance
improvements;
Identify investment priorities; and
Propose financing/ options.
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METHODOLOGY: SYSTEM CHARACTERIZATION
Task 1: Digitizing the network
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METHODOLOGY: SYSTEM CHARACTERIZATION
Task 1: Digitizing the network
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METHODOLOGY: SYSTEM CHARACTERIZATION
Task 1: Digitizing the network
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METHODOLOGY: SYSTEM CHARACTERIZATION
Task 1: Digitizing the network
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KEY OUTPUTS: SYSTEM CHARACTERIZATION
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KEY OUTPUTS: SYSTEM CHARACTERIZATION
UCA
Length(km)
Area(ha)
Canal density
m/ha
U1
6.76
136.48
49.56
U2
5.25
110.18
47.64
U3
6.73
134.16
50.16
U4
4.63
105.07
44.10
U5
5.14
126.65
40.58
U6
3.30
59.94
55.01
U7
5.69
107.73
52.80
U8
5.23
120.94
43.24
U9
3.65
70.10
52.04
U10
3.16
61.18
51.60
U11
2.49
44.41
56.03
GrandTotal
64.48
1,076.85
59.88
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KEY OUTPUTS: SYSTEM CHARACTERIZATION
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KEY OUTPUTS: SYSTEM CHARACTERIZATION
UCA
Length (km)
Area (ha)
Canal
density
m/ha
MainCanal
69.01
2,641.55
26.12
U1
27.54
196.32
140.27
U2
29.04
550.74
52.72
U3
33.19
433.09
76.63
U4
53.80
1,044.01
51.53
U5
16.74
361.64
46.29
U6
6.40
55.73
114.83
Total
166.71
2,641.55
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63.11
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KEY OUTPUTS: SYSTEM CHARACTERIZATION
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KEY OUTPUTS: SYSTEM CHARACTERIZATION
UCA
MIAD
M10
M9
M11
M17
M12
M13
M14
M15
M16
H18
H20
H19
M5
M6
M7
M8
M1
M2
M3
M4
H1
H6
H7
H8
H2
H3
Length(km)
Area(ha)
Canallengthm/ha
7.77
90.00
86.34
3.51
33.00
106.27
5.92
51.00
116.04
2.98
48.00
61.99
8.92
139.00
64.14
5.06
77.00
65.66
4.19
68.00
61.58
8.11
106.00
76.48
4.84
47.00
103.03
10.88
132.00
82.43
8.99
115.00
78.19
6.96
115.00
60.49
8.17
111.00
73.65
6.64
75.00
88.57
7.16
64.00
111.88
3.29
49.00
67.24
2.20
25.00
87.98
9.05
80.00
113.16
3.24
41.00
79.01
4.67
53.00
88.17
10.47
132.00
79.28
4.44
73.00
60.77
13.13
111.00
118.28
7.79
83.00
93.86
7.97
96.00
83.06
7.30
92.00
79.32
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8.20
108.00
75.96
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METHODOLOGY: LOSS ASSESSMENT
Canal loss mainly comprise of seepage,
evapotranspiration (EVT) & leakages
 The water balance (inflow/outflow) method will be
used for quantifying canal loss-this will not interrupt
irrigation program
 Seepage rates will be measured using inflow/outflow,
ponding and seepage meter methods
 Calibration and possibly repair of all
measuring/regulating canal structures will be
necessary to facilitate flow measurements-critical in
this study

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METHODOLOGY: LOSS ASSESSMENT
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METHODOLOGY: LOSS ASSESSMENT
Ponding method
To eliminate the effect of wind, the
rate of drop should be measured at
each end of the pool and averaged.
Staff or hook gauges attached to
existing structures or stakes driven into
the canal bed should be used as shown
in the figure below.
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PRELIMINARY RESULTS: LOSS ASSESSMENT
Distance from Dept Widt Area
point [m]
h [m] h [m] [m^2]
2.3
0
0
2.1 0.25 0.2 0.05
1.8 0.42 0.3 0.126
1.5 0.47 0.3 0.141
1.2 0.43 0.3 0.129
0.9 0.35 0.3 0.105
0.6 0.2 0.3 0.06
0.4
0 0.2
0
Avera
ge
Veloci
Veloci Veloci ty at
ty 2 ty 3 Point
Velocity 1 [cm/s [cm/s [cm/s Discharge
[cm/s]
]
]
] [m^3/s]
0
0
0 0.00
0.000
23.5 24.1 20.2 22.60
0.011
51.9 50.4 49.5 50.60
0.064
44.2 40.3 39.5 41.33
0.058
27.7
28 28.5 28.07
0.036
22.1 22.1 21.6 21.93
0.023
4.1 3.9
2 3.33
0.002
22
0
0
0 0.00
0.000
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Total Discharge
[m^3/s]
0.195
PRELIMINARY RESULTS: LOSS ASSESSMENT
Site
Site 1
Site 2
Site 3
Gross loss Efficien
cy
Offtak m/day
e
%
% loss to
closed
offtakes
%
Gross loss due
to
INFILTRATION
and EVAPO.
mm/day
0.094 0.98
0.358 0.89
0.70
0.80
28.05
71.53
0.470 0.88
0.85
70.48
0.707 0.51
0.90
70.73
Site 4
Site 5
Site 6
Site 7
Site 8
Site 9
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0.177 0.85
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0.50
88.33
METHODOLOGY: WATER BALANCE MODELING
Thiba system linkages
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METHODOLOGY: WATER BALANCE MODELING
Elements of the water balance model
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PRELIMINARY RESULTS: WATER BALANCE MODEL
Unit
Main Canals
IWR m3/day
SL m3/day EL m3/day
-
179.56
359.11
U1
11,792.28
32.47
64.94
U2
9,519.29
24.94
49.89
U3
11,591.65
33.99
67.99
U4
9,078.19
22.41
44.82
U5
10,942.63
25.11
50.23
U6
5,178.76
18.20
36.39
U7
9,308.14
27.12
54.24
U8
10,449.02
24.95
49.89
U9
6,056.82
16.48
32.97
U10
5,285.65
14.72
29.44
U11
3,837.36
12.04
24.08
Grand Total
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93,040
432
864
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PRELIMINARY RESULTS: WATER BALANCE MODEL
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PRELIMINARY RESULTS: WATER BALANCE MODEL
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ON-GOING SIMULATION STUDIES
Design, operation and maintenance issues for example what is the
effect of changes on cropping calendar and system layout
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ACKNOWLEDGEMENT


The implementing team comprising of Dr. F. Gichuki,
R. Wanjogu, A. Owilla, D. Maina and S. Muturi wish
to thank the General Manager, NIB for funding this
project
Thank you
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