THE FEDERAL DEMOCRATIC REPODUC OF ETHIOPIA
MINISTRY OF WATER RESOURCES
Arjo-Dedessa Irrigation Project
Feasibility Study Report
VOLUME - III
Water Resources
VOLUME - III (c)
Annexure - 10 Irrigation and Drainage Part - I Report
May, 2007
Addis Ababa
WATER WORKS DESIGN & SUPERVISION ENTERPRISE
IN ASSOCIATION WITH
INTERCONTINENTAL CONSULTANTS AND TECHNOCRATS INDIA PVT LTD
P.O Bo\ 2561. Addis Ababa Ethiopia
Tcl:(25l)l 614501/631890 Fax (1251)1 6l5371E-niail: w w d.s.eatelecom net ciARJO-DEDESSA IRRIGATION PROJECT
FEASIBILITY STUDY REPORT
CONTENTS OF THE REPORT
SERIAL NO.
1
2
3
VOLUME NO.
PARTICULARS EXECUTIVE SUMMARY MAIN REPORT
Part I - Report
Part II - Maps & Drawings
ANNEXURES
VOLUME-I                  SURVEY AND INVETIGATION (ANNEXURES - 1 to 3)
4
5
6
Volume -1 (a)
Volume -1 (b)
Topographic Survey, Geomorphological Studies & Geological & Geotechnical Investigation
Part I - Report Part II - Appendices
VOLUME -II NATURAL RESOURCES (ANNEXURES - 4 to 6)
Forestry, Energy & Catchment Development Plan
VOLUME - III
WATER RESOURCES (ANNEXURES - 7 to 11)
7
8
9
10
11
12
13
14
15
16
Volume - III (a)
Meteorological & Hydrological & Hydrogeological Studies 
Dam & Appurtenant Works
Volume - III (b)
Part I - Report
Part II - Drawings
Volume-III (c)
Irrigation & Drainage
Part I - Report
Part II - Drawings
Hydraulic Structures
Volume - III (d)
Part I - Report
Part II - Drawings
VOLUME IV
AGRICUTLRUE (ANNEXURES - 12 to 18)
Volume - IV (a)
Soil Survey & Land Evaluation
Volume - IV (b)
Agricultural Planning
Volume - IV (c)
Livestock, Fishenes, Agricultural Mechanization &
Agricultural Marketing
VOLUME-V
ENVIRONMENTAL AND SOCIO - ECONOMIC ASPECTS
(ANNEXURES-19 to 25)
17
Volume - v (a)
Environment. Health & Socio-economic Aspects 
18
Volume - v (b)             Organization & Management. Physical InfrastructureI
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Irrigation and Drainage1
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Irrigation & Drainage
May 2007
ii)            Construction,   maintenance   and   operation   of   field   drains   for   removing excess water from rain or irrigation from every field/farm.
iii)           Construction  and  maintenance  of  field  road  (access  track)  to  provide access  to  every  field/farm  for  transportation  of  implements  and  inputs to the field/farm and produce from the field/farm to the storage/market.
iv)          Shaping,  leveling  and  grading  of  fields/farms  for  efficient  application  of irrigation  water  as  well  as  efficient  removal  of  rain  or  irrigation  water from the fields/farms.
v)           Evolving  and  adopting  operational  procedure  for  equitable  distribution of  irrigation  water  to  various  fields/farms  served  by  an  individual  field canal.
8.2.1.1  Planning for On-Farm Development works
The planning for On-Farm Development works should satisfy the following criteria: i)          The design of water distribution system should facilitate equitable and
efficient distribution and control of irrigation water to each field/farm.
ii)
The design of drainage system should facilitate timely and efficient removal of
excess rain or irrigation water from every field/farm
iii)
The field layout and land preparation should facilitate the use of machinery in
cultivation, harvesting etc. to enable efficient soil and water management.
iv)
It should conserve soil and water and prevent water logging.
v)
The plan should minimize the cost of execution of work and loss of area
under bunds, channels and drainage.
8.2.1.2  Provision at Feasibility Study Level
In the Feasibility  Study, planning has  been done to provide irrigation and drainage channels  upto quaternary  levels, which means  that irrigation and drainage channels  are available upto 1.5 ha of field. However, they  will have to be taken to even smaller holdings  say  0.5 ha or even smaller. As  regards  land clearance and land leveling provisions  has  already  been made in the cost estimate at Feasibility  Study  for the entire command area. However, further refinement will be required at farmer level during actual operation. Drainage system has  already  been planned which will be able to avoid water logging. As regards evolving and adopting operational procedure for equitable
86
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distributions  of irrigation water to various  fields/farms, several innovative measures  i n form of hardwares  like provisions  of Adjustable Proportional Modular Outlet, flexibility factors  in design of canal capacities  etc  and softwares  in form of Rotational Water supply  at macro level (secondary  canal) and turn-by-turn supply  for fixed time in proportion to real farm area have already  been proposed at Feasibility  Study  level. However all these aspects  will be further refined at the time of detailed design, implementation a nd a ctual o peration of the system. It is  expected that by  that time Participatory  Irrigation Management, which is  expected to play  significant role in all these aspects, will be able to take some shape.
8.2.2 Off-Farm Development Works
Off-Farm Development works  are related to development of Infrastructures. With the introduction of irrigation a large number of activities, which have forward and backward linkages, will develop in and around command area. In order to ensure the envisaged increase in yield, it is  essential that proper arrangement should be made to make available in-puts  like implements, seed, fertilizer, pesticide, loan for working capital. Similarly  with increase in agricultural production it will be required to make arrangements for processing, storage, transport, marketing etc. For this  the concerned organizations, institutions  at different levels  will have be organized, developed and their proper functioning will have to be ensured.
8.3 Water management
Water Management involves  a very  broad spectrum of activities. With the introduction of irrigation it is  envisaged to achieve optimum agricultural production. It involves transformation of traditional farming system into intensively  irrigated agriculture, high with input level of fertilizer, pesticide etc  with intensive labour and high capital investment. This  is  a gradual process  a nd requires  a very  close interaction between irrigation system being maintained and operated by  irrigation engineers  and agriculture system in which farmers  along with the agriculture scientist in-charge of extension services  are involved. In this  context Water Management is  expected to play  a significant role.
The objective of water management is  to obtain optimum yield sustained on long term with conservation of water, soil and fertility  of the land without any  adverse environmental impact.
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Water Management aspect of an irrigation and drainage project basically  addresses  to
three important questions:
i)
how to irrigate (method of irrigation),
ii)
When to irrigate (timing or interval);
iii)
How much to irrigate (depth or volume of water);
Water management involves  operation of the canal system from primary  to field canal for conveyance, distribution and application of irrigation water to the field. It requires three steps:
i) Estimation of demand for irrigation water at field level in the background of
(a) prevailing agro climatic factors,
(b) stage of growth of crop and
(c) Soil characteristics;
ii)  Application of required (as assessed) quantity of water; and
iii) Assessment of the performance and impact for modification, if necessary.
8.3.1  Irrigation Schedule
During detailed design and actual operation of the canal system, irrigation schedule will be prepared, which will form the basis  for the actual operation of t he system. While preparing irrigation schedule, the following should be taken into consideration.
-    Climatic factor in form of Reference Evapotranspiration
-    Crop characteristics
o Stage of growth of crop
o Rooting depth
Soil Characteristics
o Water holding capacity
Irrigation Efficiency
8.3.2  Operation & Maintenance Manual
A detailed Manual for Operation & Maintenance of the Irrigation System should be
prepared. While preparing this Manual, the following will be taken into considerations Rotational Water Supply at macro-level (secondary canal level)
- Turn-by-Turn water supply for fixed duration in proportion to the area of
individual field at farm level
Introduction of Participatory Irrigation management
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TABLE OF CONTENTS
PLANNING FOR IRRIGATION SYSTEM--------------------------- ------
I I Introduction
/ / / Central
112 Change in Concept
I I J Sub Systems of Irrigation System
/ I 4      Optimization of sub Systems
115    Participating Irrigation Management
116       Planning and Design Criteria 
1.2       Location of the Project
13        Gross Command area (GCA)
13 1    Culturable Command Area (CCA)
13 2    Topography
13 3     Soil characteristics
I 3 .4   Land suitability
15 Components of the Project
15 1 Dam & Appurtenant H'orks
I 5 2 Outlets
I 6 Canal System
161 Nomenclature
1.6.2        Numbering of components of canal
16 3 Primary Canals ..............................................................
16 3 1 Right Primary Canal
1.6.3.2 Left Primary Canal
1.6.3.3 Fixation of Full Supply Level (FSL)
1.6           4 Macro Irrigation System
16 5 Micro-Irrigation System for Sample Area
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3 3
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5 5
6
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7 
.7 
.7 S
S
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16.5.1 Sample Area........................................................ ............................
1 6 52 Layout of Micro-Irrigation System
1 6 5 3 Secondary Canals
1.6.5.4 Tertiary and Quaternary canals 
1.7   Water Quality for irrigation
2  CROP WATER REQUIRMENT & CANAL CAPACITY-------- - ------------ --------------------- --------------- 18
10
10
11
17
2.1           INTRODUCTION
2 2 Procedure for Calculation 2.3 Sources of Climatic Data
2 4 Estimation of ETo 
,s
18
19
19
2.5 Cropping Pattern.......................................... ................................................................................ 22
2.5 I Planting Dates and Crop Calendar 29
2 5.2 Crop Coefficient (kc)
2 6 Effective Rainfall
.......................................................................... 29
30
2.7           Calculation of Crop Water Requirement
30
2 8 Methodof Irrigation
..... .36
2.9           Efficiency of Irrigation System
36
291 Efficiency for Unlined Canal System
2.9           2 Field Application Efficiency....................................................................... ....... ...... ......
3.9.3  Overall Irrigation Efficiency
2.9.4  Measures for Improving Irrigation Efficiency 2.9.5 Participatory Irrigation management (PIM) 38
2.9           6 Losses in Different components of Canal system
.37
. .... .. 37
37
37
38
2 10 Peak Design duty at the head of Primary canal 39 2 11 Flexibility Factor for the Main Canal
2 12 Monthly Water Requirement from Dam Site
2.13 Irrigation scheduling & Water management
3. HYDRAULIC DESIGN OF CANALS...........................................
3 1 INTRODUCTION
3                 2 design Criteria
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3.3 DESIGN OF UNLINED IRRIGATION CHANNELS
3.4 Hydraulic Particulars of Canal System
4 CANAL STRUCTURES
4.1  General.....................................
4.2  Structures on Primary Canals
4.2.1 Intake structures
4.2.2  Cross-Drainage Works
4.2.3 Control Structures
4.2.4   Road Bridge / Foot Bridge
4.2.5  Foot Bridges
4.2.6   Total number of structures...
4.3  Structures in Sample area
4.3.1   Outlet
4.3.2   Drops on Secondary Canals. ..
4.3.3  Drops on Tertiary canals
4.3.4  Parshall Flume
4.3.5   Duckbill weir
4.3.6   Road Bridge/Foot Bridge
5 LONGITUDINAL PROFILES AND CROSS- SECTIONS-----------
5.1  Longitudinal profiles67
May 2007
so
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50
50
51
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54
55
67
5.1.1     Longitudinal Profiles of Primary Canals 67
5.1.2  Longitudinal Profiles of Secondary Canals68
5.1.3   Longitudinal Profile of Tertiary Canals........................................................................................................68
5.2  Cross-Section of Canal68
5.2.1  Typical cross-section for Primary Canal 68
5.2.2   Typical Cross-Section for Secondary Canal69
5.2.3   Typical Cross - Section for Tertiary Canal
5 2.4 Typical Cross-Section for Quaternary Canals70
5.3  Service Road70
6. HYDRAULIC DESIGN OF CANAL STRUCUTERS
6.1  General71
6.2  Structures on Primary Canals71 6.2.1        Intake structures7/
6.3  Control Structures71
69
■••••■••••••••71
6.4  Cross Drainage Works.....................................................................................................................72
6.5  Road/Foot bridge 72
6.6  Structures on Distribution Network72
6.7  Design Calculations72
6.8  Detailed Drawings73
6.9  Estimate73
7 PLANNING AND DESIGN OF DRAINAGE SYSTEM74
7.1  Introduction74
7.2  Impact Irrigation on Existing Ground Water74
7.2 I Existing Natural Drainage System
7.2.2  Existing Ground Water Level
7.2.3  Ground Water Recharge from irrigation 75
7.2.4  Ground Water Recharge from Seepage from Canal System 7.2.5  Surface Water Logging 75
7 3 Need for Surface Drainage System
7.4  Nomenclature & Numbering of Drainage System76
7.5   Macro-Drainage System77
7.6  Layout of Micro-drainage System in Sample Area77
74
74
75
76
7.7 
Design                   Criteria
for                   Surface                   Drains
78 
7.7. / Field Drains 78
7.7.2        Design Details 79
7.8  Longitudinal Profile81
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7.9           Cross-Section of Drains81
8 FARM DEV ELOPMENT WORKS AND WATER MANAGEMENT85
8.1  Genf.rai85
8.2  Farm Development Work85
8.2.1       On-Farm Development (OFD) Works#5
8.2.1                      1              Planning              for              On-Farm              Development              works              86 
8 2.1.2 Provision at Feasibility Study Level 86
8.2.2    Off-Farm Development Works 87
8.3  WATER MANAGEMENT 87
8.3.1    Irrigation Schedule88
8.3.2    Operation & Maintenance Manual88
List of Table
Table I I Land Suitability for Different Crops under Arjo-Dedessa Command Area
.6
Table           1.2          List           of           Secondary           Canals           Under           Right           Primary           Canal12 
Table          1.3         List          of          Secondary          Canals          Under          Left          Primary          Canal          13 
Table       1.4      Details       (List)      of       Tertiary       Canals       under       Secondary       canal       RS-16      14 
Table 1.5 Details (List) of Tertiary Canals Under Secondary canal RS-17 Table 1.6 Details (List) of Quaternary Canals Under Sample area
15
16
Table 1.7  Selected Physio-Chemical and Bacteriological Water Analysis Results for Dedessa 17 
Table        2.1       Summary        of        Meteorological        Characteristics        of        the        project        areaI9 
Table      2.2     Estimated      Monthly      ETo      of      Arjo-Diddessa      Project      Area      (in      mm/month)    21 
Table            2.3           Values            of            ETo            for            Arjo-Diddessa            Irrigation            project22 
Table    2.4(a)   Cropping    pattern    -   distribution    of    area    under    Phase-I   (Crop    Rotation    1)    23 
Table    2.4(b)   Cropping    pattern    -   distribution    of    area    under    Phase-I   (Crop    Rotation    2)   23 
Table    2.5(a)   Cropping    pattern    -   distribution    of    area    under    Phase-II   (Crop    Rotation    1)   24 
Table    2.5(b)   Cropping    pattern    -   distribution    of    area    under    Phase-II   (Crop    Rotation    2)   24 
table
2.6 
CROP
CALENDAR
FOR
Table 2.7 monthly averages and 75% & 80% dependable effective rainfall (in mm) Table 2 8(a) CROP WATER REQUIREMENT Phase I Rotation I
29 
.... 30 3|
Table          2.8(b)        CROP         WATER         REQUIREMENT         Phase          I         Rotation          II         .         32 
Table 2.9(a) CROP WATER REQUIREMENT Phase II Rotation I
Table 2.9(b) CROP WATER REQUIREMENT Phase II Rotation II Table 2.10 Gross water requirement at primary canal head (month wise).
33
. 34
35
Table          2.11         Efficiency          for          Different          Components          of          Canal          System          39 
Table       2.12      Peak       duties       for       different       crop       rotations       under       Phase-I      &      II      40 
Table        2.13       Flexibility        Factor        for        different        components        of        Canal        system        40 
Table 2.14(a) Depth of Water for various Scenarios (mm)
...
.41
Table 2.14(b) Volume of Water for Various Scenarios (Mm ) for 13665.27 ha Command Area
3
........................................................................................................................................................................... ...
Table 3.1 Hydraulic Particulars for Right Primary Canal
Table      3.2     Hydraulic Particulars for Left Primary Canal Table     3.3     Hydraulic Particulars for Secondary Canal-RS-16 Table     3.4     Hydraulic Particulars for Secondary Canal-RS-17
46
47
4S
45
Table     3.5     Hydraulic Particulars for Tertiary Canals Under Secondary canal-RS-16 Table     3.6     Hydraulic Particulars for Tertiary Canals Under Secondary canal -RS-17. Table 4 1(a) List of Aqueduct on Right Primary Canal
Table 4.1(b) List of Aqueduct Structures on Left Primary Canal 55 
Table 4 2(a) List of Syphon aqueduct on Right Primary Canal
Table 4.2(b) List of Syphon Aqueduct on left Primary Canal
Table 4.3(a) List of Cross Drainage Works, with canal in earthen section on ...
49
49
55
56
56
57
Table     4.3(b)    List     of     Cross     Drainage     Works,    with     canal     in     earthen     section     Left     57
Table 4.4(a) List of Canal Syphon Structures on Right Primary Canal
Table 4.4(b) List of Canal Syphon Structures on Left Primary Canal
58
58
Table 4.5(a) list of Proposed head and cross Regulators /Escape on Right 58
Table 4.5(b) List of Proposed head and cross Regulators/Escape on Left 59 
Table 4.6(a) List Of Head Regulator on Right Primary Canal
60
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Table 4.6(b)List of Head Regulator on Left Primary Canal..................................................................................  62
Table 4.7(a)List of Road Bridges on Right Primary Canal....................................................................................... 65
Table 4.7(b)List of Road Bridges on Left Primary Canal........................................................................................ 65
Table 4 8(a)     List of Foot Bridges (Cattle Crossings) on Right Primary Canal ...
65
Table 4.8(b)     List of Foot Bridges Provided in left Primary Canal................................................................... 66
Table 7.1           Details of Secondary Drains-Naturally existing or proposedfor construction 82
Table 7.2           Hydraulic particulars for Secondary Drain RSD-15.................................................................... 83
Table 7.3           Hydraulic particulars for Tertiary drains in sample area......................................................... 84
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1 PLANNING FOR IRRIGATION SYSTEM
1.1     Introduction 1.1.1  General
May 2007
Before taking up planning and design of irrigation system it is  considered essential to discuss  in very  brief a few issues, related to water resources  development in general and irrigation system in particulars, which have assumed importance during recent times  and which are influencing the planning and design of irrigation system in a significant way. Some of them are discussed here under in very brief.
1.1.2  Change in Concept
Though irrigation is  being practiced since time immemorial, it has  undergone significant conceptual changes  during recent times. One of the most important conceptual changes  is the change from previous  subsistence level to the optimization of agricultural production from limited resources  of land and water, which are becoming scarce day  by  day  in view of ever increasing demand for explosive growth of population. However, the need to provide irrigation in more and more new areas, which were hitherto considered very  difficult and/or not very  suitable for irrigation, is  also making the task  very  challenging. In view of increase in demand for water for other sectors, its  availability  is  decreasing for irrigation sector, which is  at present consuming a lion share of water resources. This is making the task of planning & design of irrigation projects  more challenging. This  shows  that irrigation planning has  to take into consideration to facilitate irrigation in more area with less  water, which suggests that the water use efficiency  for irrigation has  to increase considerably  from the low level of efficiency prevailing at present.
1.1.3  Sub-Systems of Irrigation System
The irrigation system consists  of two major sub - systems. These are canal sub-system & agricultural sub-system. The canal sub-system comprises  the head works, (which may  be a dam with storage system or diversion structure - a barrage or weir) and the canal system consisting main (primary) canal, distributary  (secondary  canal), minor (tertiary) and quaternary  canals  (water course). The canal system has  to be planned and designed in such a way  that it fits  appropriately  into the topographic  features. Agricultural sub-system comprises  the farming and its  related activities. This  sub-system has  to be planned and designed in such a way  that it fits  into the prevailing land & soil characteristics, and climatic factors besides other socio-economic and agro-economic conditions.
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1.1.4 Optimization of sub-Systems
The irrigation system for Arjo-Dedessa has  been planned with consideration of above aspects. Efforts has been made to plan the agricultural sub-system such that it fits into the prevailing agro-climatic factors and the irrigation sub-system has been planned to fit best into topographic features. The irrigation system has been planned for the optimum water use efficiency and to achieve optimum agricultural production from available land and water resources. In order to achieve these objective innovative measures like structured network, rotational water supply at secondary level and turn-by-turn water distribution at field level, have been proposed to be introduced. It is  expected that the introduction of these measures, along with other innovative measures will help in achieving reliability, timeliness, adequacy, equitable distribution and flexibility in the system.
1.1.5 Participating Irrigation Management
It is also intended to introduce Participatory Irrigation Management (PIM), which will help in improving water use efficiency and quality of irrigation services.
1.1.6 Planning and Design Criteria
Accordingly the hardware and software in the planning and design of the irrigation are being provided. The overall planning & design of the irrigation system has been undertaken in accordance with the design criteria already prepared and submitted under Phase-ll Interim Report of the Feasibility Study and which has been accepted by the client.
1.2    Location of the Project
Geographically the project area is situated between 8 -3O’-39”
o
to 8°-39'-32". North latitude
(941399 & 957395 Northing) and between 36°-22'-53" to 36°-38'-15". East longitude (211867 & 240240 Easting). The command area is located in Bedele & Getchi woredas of lllubabor zone and Jima Arjo woreda of Eastern Welega zone under Orimiya Regional State. The command is situated at a distance of about 550 km from Addis Ababa and 220 km from Jima and is accessible from Addis Ababa through Jima (340 km asphalt road from Addis) and Bedele (150 km road from Jima). Bedele is the nearest town to the command on the left bank of the river. The left bank of the dam site is also about 60 km from Bedele. Arjo is  the town nearest to the command area on the right bank  of the river. Arjo is accessible from Addis Ababa through Nekemte, the total distance from Addis Ababa being about 400km. But there is no approach to the command area from Arjo.
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Command area lies on both the bank - left and nghl of river Oedessa, and covers the
following kebeles falling under the woredas as given below.
Right Bank
Zone Woreda
Eastern Welega Kebeles
Left Bank
Zone
Woreda
lllubabor
Kebeles
Jima Arjo
1 - Lugama
Bedele
1.  Lilokaine
2 - Meta
2.  Chafiejalela
3 - Bedhasadedessa
3.  Bekelichbiftu
4.  Bildimadaru
5.  Chilalobildima
6.  Ambeleta
7.  Kolosirie
8. Harotalessa
Getchi
1. Chitubosena
2.  Maris
3.  Yebelo
4.  Wakel
The location of the project area including the command and the reservoir with respect to zones have been shown in Fig 1.1 and Fig 1.2 shows the location of the command area with respect to woredas.
1.3    Gross Command Area (GCA)
The command area lies on both banks of the river below the dam. There are two primary canals - Right Primary canal and Left Primary canal offtaking directly from the dam. The outlets for the two primary canals are located on either bank of the dam.
The gross command area is 10,998 ha on the left bank extending over about 8 kebels of Bedele Woreda and 4 kebels of Getchi woreda under lllubabor zone. The gross command area on the right bank  is  about 6827 ha extending over three kebels  under Jima Ago Woreda. Thus the total gross command area is about 17,825 ha
1.3.1 Culturable Command Area (CCA)
The culturable command area, which represents the culturable area has been assessed as 13,665 ha, which works  out to 76.67% of the gross  command area The culturable command area excludes the area which is not suitable and/or available for cultivation such area occupied by rivers, drainage channels, forest, hills, settlements or rocky land. etc. The culturable command on left bank is 7450 ha and that on right bank is 6215 ha.
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1.3.2 Topography
The elevation in the command area varies  between 1348 to 1330 a.m.s.l. The detailed soil survey has been carried for a gross area of 36,765 ha against the identified gross command area of 17825 ha. The results of detailed soil survey show that about 45% of the command area is level (0-1% slope), 7%area nearly level (1-2% slope), 28% of the area is having very gentle (2-4% slope) and 20 % of the area gentle (4-6% slope). In general the command area is having a rolling topography. On both sides of the river there are some isolated hills rising above the average level of the plain.
1.3.3 Soil characteristics
The results of the detailed soil survey of the proposed command area indicate that the most extensive soils of the project are vertisols largely occurring in the bottom of the valley. They are subjected to seasonal flooding and cover 17692 ha which is  48.09% of the total surveyed area. The well drained reddish brown soils, which include Luvisols, Cambisols and Nitisols, are mostly  located on upland of isolated hills  and gentle undulating to rolling land that cover 9026 ha which accounts  for 24 54% of the total surveyed area. The remaining area is  occupied by  miscellaneous  lands, which cover 10,068 ha and constitute 27.37% of the total area. The soil map of the command area is available at Fig 1.3.
The soil in the command area is  very  deep,. The fertility  status  of the soils  of the project area is  medium to very  high. The major constraints  of the area are steepness, poor drainage of the bottom land of the valley, uneven surface, compaction and vegetation cover.
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1.3.4Land suitability
The detailed land suitability assessment of the study area has been carried out for irrigated agricultural development by  using soil and land resource data. The detailed land suitability assessment of the study  area has  been done for irrigated agriculture development which includes  cultivation of rice, wheat, maize, sugarcane, vegetables  and forage etc. The land suitability  assessment has  been done comparing the major land quality  (actual conditions) of the study  area with land use environmental requirement for different land use types. Accordingly land suitability maps for major irrigated crops have been prepared.
The results  of land suitability  assessment have been given in Table 1.1. This  table shows the extent of area suitable for different types  of crops  proposed in the project area. The figures available in the table show that sufficient suitable land is available for different crops proposed in the command area according to the proposed cropping pattern. Fig 1.4 shows the layout of the canal system superimposed on the land suitability map.
1.5 Components of the Project
The Arjo-Dedessa Irrigation Project consists of the following major components.
1.5.1 Dam & Appurtenant Works
A 40.6 m high earth & rock  fill dam has  been proposed at 36°-40'-04" E longitude and 80-31-12" N latitude (UTM-243188 Easting and 942445 Northing) with gross  and live storage capacities  of 1341.2 & 466.5 Mm3 respectively. The FRL and MDDL (with respect to irrigation) have been fixed as EL 1356 & 1350 m. respectively.
1.5.2 Outlets
Two outlets (intake structures for canal) - one on either side - have been provided to cater for the needs of the primary (main) canal proposed on either bank of the river. The details of the outlets are as follows:
Particulars
Right outlet
Left outlets
i) Location
At saddle No. 2
Near    the    left    abutment (about 15 m from the endj
ii) Type
RCC duct
RCC duct
iii) Size
1.7 x 1.7 m
2.0 x 1.5m
iv) Discharge
7.52 m3/sec
9.015 m3/sec
v) Canal FSL
EL 1348 amsl
EL 1348.0 amsl
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1.3.4 Land suitability
The detailed land suitability assessment of the study area has been carried out for irrigated agricultural development by  using soil and land resource data. The detailed land suitability assessment of the study  area has  been done for irrigated agriculture development which includes  cultivation of rice, wheat, maize, sugarcane, vegetables  and forage etc. The land suitability  assessment has  been done comparing the major land quality  (actual conditions) of the study  area with land use environmental requirement for different land use types. Accordingly land suitability maps for major irrigated crops have been prepared.
The results  of land suitability assessment have been given in Table 1.1. This table shows the extent of area suitable for different types  of crops  proposed in the project area. The figures available in the table show that sufficient suitable land is available for different crops proposed in the command area according to the proposed cropping pattern. Fig 1.4 shows the layout of the canal system superimposed on the land suitability map.
1.5 Components of the Project
The Arjo-Dedessa Irrigation Project consists of the following major components.
1.5.1 Dam & Appurtenant Works
A 40.6 m high earth & rock fill dam has been proposed at 36°-40'-04" E longitude and
80-31-12" N latitude (UTM-243188 Easting and 942445 Northing) with gross  and live storage capacities  of 1341.2 & 466.5 Mm3 respectively. The FRL and MDDL (with respect to irrigation) have been fixed as EL 1356 & 1350 m. respectively.
1.5.2 Outlets
Two outlets (intake structures for canal) - one on either side - have been provided to cater for the needs of the primary (main) canal proposed on either bank of the river. The details of the outlets are as follows:
Particulars
Right outlet
Left outlets
i) Location
At saddle No. 2
Near    the    left    abutment (about 15 m from the end}
ii) Type
RCC duct
RCC duct
iii) Size
1.7 x 1.7 m
2.0 x 1.5m
iv) Discharge
7.52 m3/sec
9.015 m3/sec
v) Canal FSL
EL 1348 amsl
EL 1348.0 amsl
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Table 1.1 Land Suitability for Different Crops under Arjo-Dedessa Command Area
Suitability Class
Rice
Wheat
Maize
Sugarcane T Vegetable
S1
--------------------- --------------------
S2
467 66
234.38             3295 28
S3
4428.05
1171.94
1639 6
2751 95
Sub-Total Suitable
4428.05
1639.6         1639.6
2986.33
N1
1346.73
1346 73
9460 16
12755.44
230 89
N2
2290 82
3732 54
Sub-Total unsuitable
2290.82      5079.27
3732 54
5079.27
3732 54
3732 54
Grand Total
6718.87]     6718.87
6718.87
6718.87
3732 54
3963 43
16718.87
Pasture
2114 56
2114.56
1346 73
3732 54 I 5079.27^ 7193.83
Besides,   the   dam   &   appurtenant   works   the   major   component   of   project   consists   of   the irrigation and drainage system. These are discussed in detailed
1.6    Canal System
1.6.1 Nomenclature
The   following   nomenclature,   as   prevalent   in   Ethiopia,   has   been   adopted   However   the internationally prevalent nomenclature has also been indicted for better understanding:
Prevalent in Ethiopia         Prevalent       internationally and In other countries
i) Primary canal                    Main canal
I
li) Secondary Canal
—  - —
111) Tertiary canal
____________________
iv) Quaternary canal
L - _. - - - - . _ -
v) Field canal
Distributary Minor
Water course Field channel
Adopted in the Report
Primary (Main) canal (equivalent to distributary) Secondary canal-
(equivalent to minor)
Tertiary canal-(equivalent
to water course)
Quaternary canal-
(equivalenl to field
channe—- l) ----------------------------- j
It may  be noted the nomenclature as  prevalent in Ethiopia has  been adopted in this  Report. There are two Primary  Canals  - Right Primary  & Left Pnmary  canal - one on either side The discharge of right Primary  canal is  1 52 mJ/sec  and that of Left Primary  canal is  9 015 m3/sec. Though the standard' nomenclature prevalent in Ethiopia has  been adopted the functions  of the different components  of the canal system have down graded one step below As  the discharges  of Right Primary  & Left Primary  canals  are very  low and they  are almost equivalent to distributary, they  are functioning as  distributaries  Therefore (he secondary  and tertiary  canals  are functioning as  minors  & watercourses  respectively  and the quaternary canals are functioning as field channels.
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1.6.2 Numbering of components of canal
Since there are two Primary Canals - one on each bank, they have been named as Right Primary Canal (RPC) and Left Primary Canal (LPC). The secondary canals on each bank i.e. under RPC & LPC have been serially  numbered by  assigning a number as  subscript after the letter S' and capital letter R & L have been pre-fixed to distinguish the secondary canals  under Right or Left Primary  Canal viz. RS-1, 2, 340 and LS-1.2....45. The tertiary canals have been numbered according to their location on the respective secondary 
canal under Right Primary Canal or Left Primary Canal as give below:-
Location of Tertiary canal
Right Primary Canal
Left Primary Canal
Linder Secondary Canal No.1
RT-1-1
RT-1-1
RT-1-3
RT-2-1
RT-2-2
RT-2-3
LT-1-1
LT-1-2
Under Secondary Canal No.2
LT-1-3
LT-2-1
LT-2-2
LT-2-3
The sequences for other tertiary canal beyond number three a nd other s econdary canal beyond number two will continue in similar way. In similar fashion quaternary canals will be numbered serially according to their location under the Tertiary canal. For example, the first quaternary  canal under Tertiary  canal no. 2 of secondary  canal number 9 of the Right Primary canal will be numbered as RQ-9-2-1.
1.6.3    Primary Canals
1.6.3.1 Right Primary Canal
Taking off from the outlet provided at saddle dam No. 2 with a head discharge of 7.52 m/sec, the total length of the canal is 44 km and it is a contour canal in its entire length. In upper reach the command area lies  on both banks  of River Wama, which is  a major tributary of Dedessa River, joining it downstream of the proposed dam. After taking off from the right out left (Intake structure) provided in the saddle no. 2, the alignment of Right Primary  Canal runs  parallel to the course of River Wama in upstream direction on its  left bank and then it crosses the Wama River at 8.5 km through an aqueduct. There after the alignment runs  on the right bank  parallel to the course of River Wama in downstream direction. It crosses an other natural drainage at 13.75 km through an other aqueduct and there after it runs parallel to river Dedessa.
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Since it is a contour canal, its entire command lies on one side, left side of the alignment and extends  upto the bank  of River Dededssa. The Right Primary  Canal being a contour canal, it crosses a large number of natural drainage channels on which cross-drainage (CD) works  have been proposed. One secondary  canal has  been provided mostly  on the ridge between two natural drainage channels.
1.6.3.2Left Primary Canal
The Left Primary  Canal takes  off from the left outlet located near the left abutment of the
3
dam. The head discharge is 9.015 m /sec and the total
length is 60 km. In its initial reach,
it is aligned on steep slope covering only a very narrow command between the hills and the river Dedessa. Gradually the command area widens and again in the end it narrows down. Similar to the Right Primary Canal, the Left Primary Canal also crosses a large number of natural drainage channels, where CD works have been proposed. Between the two natural drainage channels, one secondary  canal, which takes  off from the primary  canal and runs on the ridge, has been proposed.
1.6.3.3Fixation of Full Supply Level (FSL)
The FSL of the Primary Canals at their head i.e., near the off take has been fixed very judiciously. Care has been taken to see that there is no ideal length of the canal due to
deep cutting and in case it is not avoidable, it is kept to the minimum Efforts have been
made to delineate the command areas on the topographic map and determine the
maximum ground elevation of fields. Accordingly FSL of the Primary canal has been fixed
so that it is able to provide flow irrigation under gravity in its entire command. Sufficient
working head had been provided between the proposed FSL of the Primary C anals a nd operative MDDL in the reservoir.
The full supply level (FSL) of both Primary Canals - Right and Left - has been fixed at EL 1348 amsl. This  has  been fixed with the consideration of providing gravity  irrigation in the proposed command area. This FSL has been fixed such that no area, which is suitable for cultivation, is  left out of command and at the same time, the canal does  not have unnecessary idle length and either excessive cutting or filling.
While planning and designing for the lay out of the canal system the fixation of full supply levels  (FSL) in different components  of the canal system has  been finalized with working head as follows.
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Off taking channel
Secondary canal Tertiary canals Quaternary Canals
Parent channel
Primary Canal Secondary canals Tertiary Canals
May 2007
Working head
30 cm
15 cm
15 cm
1.6.4  Macro-Irrigation System
The lay  out of macro-irrigation system, comprising the primary  and the secondary  canals, has been planned on the basis of the contour map available at a scale 1: 10,000. As stated earlier the Primary  canals  are contour canals, where as  the secondary  canals  have been aligned on ridges between two natural drainage channels. The alignments of the secondary canals  have been marked on the map along with the Primary  canals. However, the layout for secondary  canals  (except in the sample area) is  only  tentative to indicate the broad planning of the irrigation system. Normally  the Primary  canals  (equivalent to main canal) and Secondary  canals  (equivalent to distributary) form the part of macro-irrigation system. But in this case the size of the command area and consequently the discharging capacity of Primary  canal is  small, which is  almost equivalent to a distributary  in major canal system. Therefore the secondary  canals  are functioning as  “minors" and as  such they  are forming the part of micro-irrigation system. Accordingly  the planning & design of secondary  canals have been considered under micro-irrigation system.
The layout of macro-irrigation for the command area of both Right and Left Primary canals has  been shown on contour maps  scale 1:10,000 in seven sheets, which have been provided in a separate volume along with this  Report as  Part-ll-Drawings. However, the layout on a condensed scale has been made available in this Report at Fig 1.5 for ready reference.
1.6.5 Micro-Irrigation System for Sample Area
While the planning for the layout of the macro-irrigation system, consisting of Primary  & Secondary Canals, has been done for the entire command, the planning for micro-irrigation system comprising secondary, tertiary, and quaternary  canals  has  been done for the sample area only. For the purpose of micro-irrigation planning a sample area measuring about 756 ha has been selected. The sample area is located under the command area of secondary canal no RS-16 (340 ha) and RS-17 (416 ha). The main criteria for the selection of the sample area is  that it should be true representative - in respect of all aspects  i.e, topography, soil and land characteristics - of the command area. In the selected sample
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area, complete piann.nq tor tertiary and quaternary canals in .he entire sampie area has been done on a topographic map at scale 1:5000.
1.6.5.1  Sample Area
The detailed planning and design for micro-irrigations system has been done under the sample area, which covers the following secondary canal under Right Primary canal.
i)         Secondary canal No. RS-16. It takes off at km 21.327 of Right Primary Canal and  has  a  culturable  command  area  of  408.38  ha.  However  due  to  some constraint only 340 ha has been included in the sample area at this stage.
ii)        Secondary canal No. RS-17- It takes off at km 21.788 of Right Primary canal and has a culturable command area of 495.79 ha. However, the sample area covers only 415.75 ha at this stage of Feasibility study.
It may be noted that the two secondary canals are adjoining and their command area are contiguous. As such the entire sample area is located in one block.
1.6.5.2  Layout of Micro-Irrigation System
The micro-irrigation system consists of micro-irrigation and micro-drainage sub-systems. The micro-irrigation system consists of the following:-
-    Secondary canals - (equivalent to minor)
-    Tertiary Canals - (equivalent to water course)
-    Quaternary canals - (equivalent to field channels)
Similarly the micro-drainage sub-system consists of the following:
-    Quaternary drains
-    Tertiary drains
-    Secondary drain
1.6.5.3   Secondary Canals
As discussed earlier secondary canal which is normally equivalent to distributary forms the part of macro-irrigation system. But since the command area of the primary canal is small and consequently discharge is also small, in this project it is equivalent to distributary The width of the command area under each primary canal is very small and the command area is  traversed by  a large number of small natural streams. Therefore, as  dictated by  the topographic features, one secondary canal has been provided between the two natural
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streams. The secondary  canals  offtake from the Primary canals on only one side. A head regulator has been provided in the Primary canal at its offtake. The secondary canals have been aligned on the ridges and tertiary canals are offtaking on either side.
The details  of secondary  canals  under Right Primary  canal and Left Primary  canal are available at Table 1.2 and 1.3 respectively. The tables show the number, length, command area, and the discharging capacity  of the secondary  canals. There are 45 secondary canals  having a total length of 47.19 km under Left Primary  Canals  and 40 secondary canals having a total length of 49.37 km. under Right Primary Canals.
1.6.5.4  Tertiary and Quaternary canals
The layout of the sample area is available at Fig. 1.6. The figure shows the layout of tertiary and quaternary canals along with the irrigation blocks. While tertiary canals are taking off on both sides  of secondary  canal, which is  aligned on the ridge, the quaternary  canals  are taking off from the tertiary canals only on one side because of constraint of topography as the land is slopping only on one side of tertiary.
The   average   size   of   the   irrigation   blocks   is   about   20   ha,   though   there   are   some exceptionally big block having an area of 37 ha and exceptionally small block of 6 to 10 ha.
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Table 1.2: -List of Secondary Canals Under Right Primary Canal.
No of
Secondary
Canals
Off take point
(km)
C.C.A
(ha)
Discharge
3
(m /s)
Length of the
each secondary 
canal
RS-1
0.555
49
0.057
0.4
RS-2
1.692                           91
0.106
0.37
RS-3
2.951                           51
0.06
0.4
RS-4
4.142                            60
0.07
0.4
RS-5
4.887                            86
0.101
0.35
RS-6
5.750
36
0.04
0.3
RS-7
6.123
49
0.057
0.03
RS-8
10.14
66
0.077
0.02
RS-9
10.97
24
0.028
0.1
RS-10
12.382
104
0.122
0.5
RS-11a
15.010
136
0.159
0.93
RS-11b
15.010
73.59
0.086
0.93
RS-12
16.393
115.09
0.135
0.60
RS-13
17.186
112.47
0.132
1.00
RS-14
17.756
102.32
0.12
1.20
RS-15
18.884
202.86
0.237
1.60
RS-16
21.327
408.38
0.478
2.40
RS-17
21.788
495.79
0.58
3.65
[RS-18
22.762
168.98
0.198
RS-19
1.55
23.797
227.75
0.266
RS-20
1.55
24.842
246.03
0.288
RS-21
26.347
1.50
184.31
0.216
RS-22
28.063
1.20
159.84
0.187
RS-23
28 868
1.25
83.68
RS-24
0.098
29.761
0 95
77.34
0.09
30.285
.
0.90
34.4
RS-26
RS-25
RS-27
RS-28
RS-29
RS-30
RS-31
RS-32
RS-33
RS-34
RS-35
RS-36
RS-37
RS-38
RS-39
0.04
31.332
0.60
110.98
0.13
31.836
0.90
256
0.3
32.960
41.27
1.20
0.48
33.818
0.90
176.56
0.207
34.819
590 01
0.69
35.218
255.1                    0.298
.
4 10
2 10
35.922
216.33
2 75
0.253
36.475
136.48
.
2 20
--
37.418
0.16
123.57
.
1 50
38.537
0.145
89.26
.
1 60
0.104
39 556
188.31
0 70
40.207
0.22
183.29
.
1 90
0.214
42.088
232.18
.
1 60
43.109
0.272
98.83
0 95
RS-40
44.166
0.116
53.96
11
Total
0 63
.
0 65
49 37
—
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Table 1.3: -List of Secondary Canals Under Left Primary Canal.
No of
Secondary
Canals
Off take point
(km)
C.C.A (ha)
Discharge
3
(m /s)
Length of the
each
secondary 
canal
LS-1
0.157
40.87
0.048
0.2
LS-2
3.126
33.06
0.039
0.32
LS-3
3.749
40.1
0.047
0.60
LS-4
4.638
24.48
0.029
0.30
LS-5
5.411
36.3
0.042
1.30
LS-6
6.084
64.26
0.075
0.65
LS-7
6.553
40.14
0.047
0.35
LS-8
9.89
81.52
0.095
0.90
LS-9
10.486
138.72
0.162
0.95
LS-10
13.994
120.31
0.141
0.32
LS-11
15.906
40.11
0.047
0.62
LS-12
20.16
69.17
0.081
0.95
LS-13
20.718
69.42
0.081
0.90
LS-14
21.693
52.04
0.061
0.30
LS-15
23.115
356.79
0.417
2.40
LS-16
23.617
68.08
0.08
0.30
LS-17
26.86
155.01
0.181
1.40
LS-18
27.653
70.58
6.083
0.30
LS-19
28.869
37.79
0.04
0.35
LS-20
29.526
22.89
0.027
0.50
LS-21
30.333
42.74
0.05
0.35
LS-22
31.096
1441.1
0.169
0.96
LS-23
32.44
607.79
0.711
4.65
LS-24
33.955
103.16
0.121
0.30
LS-25
35.266
87.65
0.103
0.90
LS-26
35.673
752.57
0.881
5.50
LS-27
36.718
32.09
0.038
0.30
LS-28
38.076
18.9
0.022
0.30
LS-29
38.912
30.57
0.036
0.02
LS-30
39.737
62.31
0.073
LS-31
0.30
40.137
32.31
0.038
LS-32
0.30
40.818
100.56
0.118
LS-33
0.65
41.913
102.88
0.12
LS-34
0.80
44.312
68.29
0.08
LS-35
45.008
0 20
28.22
0.033
LS-36
46.236
0.20
154.19
0.18
LS-37
47.563
0.60
176.86
0.207
LS-38
48.204
2.10
102.91
0.12
LS-39a
50.948
0 90
-
-
LS-39b
51.649
1.25
1030.7
1.206
lLS-40
54.124
4 20
331.86
0.388
LS-41
54.483
1.90
32
0.041
LS-42
54.688
0.20
68.96
0.81
LS-43
55.382
0.60
165.72
0.194
LS-44
57.644
0.30
443.24
0.519
LS-45
60.159
1.90
911.93
1.067
Total
3.60
L
47.95
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The details of the irrigation blocks and tertiary canals for secondary canal No. RS - 16 and RS-17 are available in Tables 1.4 and 1.5 respectively. There are fifteen number of tertiary canals  under RS-16. The length of tertiary  canal varies  between 1345 m to 1115m and total length of all the fifteen tertiary canals under the command of RS-16 is 10.845 km. The number of quaternary canals under each tertiary canal varies between 7 to 23 and the total number of quaternary  canals  is  224 under RS-16. Similarly  there are 2 2 tertiary  canals under RS-17. Their length varies between 142 m to1287 m and the total length of all the tertiary  canals  under RS-17 is  13.383 km. The number of quaternary  canals  under each tertiary canal varies between 4 to 23 under different tertiary canals and the total number of quaternary canals under RS-17 is 285. The details of quaternary canal under sample area are available at Table 1.6.
Table 41.4: - Details (List) of Tertiary Canals under Secondary canal RS-16
Name of Block 
(secondary 
canal)
Tertiary
canal
C.C.A
in ha
Design
capacity
m3/s
Design
capacity with
flexibility 
factor (20%)
RS-16-1
21.33
0.020
0.024
Length of
tertiary
canals 
()
m
674
RS-16-2
14.28
0.013
0.016
390
RS-16-3
25.13
0.024
0.028
816
RS-16-4
14.91
0.014
0.017
345
RS-16-5
29.63
0.028
0.033
960
RS-16-6
18.42
0.017
0.021
543
RS-16-7
32.85
0.031
0.037
RS-16
1066
RS-16-8
18.96
0.018
0021
578
RS-16-9
35.71
0.034
0.040
1115
RS-16-10
19.51
0.018
0.022
578
RS-16-11
34.85
0.033
0.039
1114
RS-16-12
19.88
0.019
0.022
633
RS-16-13
28
0.026
0.032
908
RS-16-14
16.24
0.015
0.018
585
RS-16-15
10.4
0.010
0.012
543
Total
340
10.845
14
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r1 1’
r1J
J
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] ] ] ] ] ] ] ] ] ] ] ] 1
1 1 1
1
Arjo Dedessa Irrigation Project
Irrigation & Drainage
May 2007
Table 1.5:   - Details (List) of Tertiary Canals Under Secondary canal RS-17
Name of
Block
(secondary
canal)
Tertiary
canal
C.C.A in
ha
Design
capacity
m3/s
Design
capacity with
flexibility
factor (20%)
Length of
tertiary
canals (m)
RS-17-1
6.5
0.006
0.007
522
RS-17-2
9.73
0.009
0.011
142
RS-17-3
7.57
0.007
0.009
668
RS-17-4
19.77
0.019
0.022
150
RS-17-5
8.2
0.008
0.009
580
RS-17-6
21.84
0.021
0.025
200
RS-17-7
11.24
0.011
1               0.013
574
RS-17-8
20 54
0.019
0.023
295
RS-17-9
16.32
0.015
0.018
594
RS-17-10
20
0.019
0.023
513
RS-17
RS-17-11
25.94
0.024
0.029
523
RS-17-12
19 89
0.019
0.022
768
RS-17-13
27.45
0.026
0.031
666
RS-17-14
19.64
0.018
0.022
1044
RS-17-15
37.44
0.035
0.042
682
RS-17-16
20.77
0.020
0.023
1287
RS-17-17
25.48
0.024
0.029
674
RS-17-18
21.54
0.020
0.024
868
RS-17-19
21.15
0.020
0.024
664
RS-17-20
21.63
0.020
0.024
739
RS-17-21
14
0.013
0.016
656
RS-17-22
18.11
0.017
0.020
574
Total
415
13.383
__________________________________________________________________ ____ 15
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Irrigation & Drainage
Table 1.6: - Details (List) of Quaternary Canals Under Sample area
May 2007
Secondary
canal
Tertiary
canal
Area
(ha)
Discharge
m3/s
Quaternary canal
Tertiary
drain
Area
drained
(ha)
RT-16-1
21.33
0.024
RQ-16-1-1 to RQ-16-1-13
RT-16-2
14.28
0.016
RQ-16-2-1 to RQ-16-2-7
RT-16-3
25.13
0.028
RQ-16-3-1 to RQ-16-3-16
RTD-16-1
21.33
RT-16-4
14.91
0.017
RQ-16-4-1 to RQ-16-4-8
RTD-16-2
14.28
RT-16-5
29.63
0.033
RQ-16-5-1 to RQ-16-5-19
RTD-16-3
25.13
RT-16-6
18.42
0.021
RQ-16-6-1 to RQ-16-6-11
RTD-16-4
14.91
RT-16-7
32.85
0.037
RQ-16-7-1 to RQ-16-7-21
RTD-16-5
29.63
RS-16
RT-16-8
18.96
0021
RQ-16-8-1 to RQ-16-8-13
RTD-16-6
18.42
RT-16-9
35.71
0.040
TO-16-9-1 to RQ-16-9-23
RTD-16-7
32 85
RT-16-10
19.51
0 022
RQ-16-10-1 to RQ-16-10-13
RTD-16-8
18.96
RT-16-11
34.85
0.039
RQ-16-11-1 to RQ-16-11-23
RTD-16-9
35.71
RT-16-12
19.88
0.022
RQ-16-12-1 to RQ-16-12-14
RTD-16-10
19.51
RT-16-13
28
0.032
RQ-16-13-1 to RQ-16-13-19
RTD-16-11
RT-16-14
16.24
0.018
RQ-16-14-1 to RQ-16-14-13
RTD-16-12
34.85 1 19.88
RT-16-15
10.4
0.012
RQ-16-15-1 to RQ-16-15-11
RTD-16-13
28
Total
340.1
RT-17-1
65
0.011
RQ-17-1-1 to RQ-17-1-4
RT-17-2
9 73
0.007
RQ-17-12-1 to RQ-17-12-11
RT-17-3
7.57
0.022
RQ-17-2-1 to RQ-17-2-4
RTD-17-1
6.5
RT-17-4
19.77
0.009
RQ-17-13-1 to RQ-17-13-14
RTD-17-2
9.73
RT-17-5
8.2
0.025
RQ-17-3-1 to RQ-17-3-4
RTD-17-3
7 57
RT-17-6
21.84
0.009
RQ-17-14-1 to RQ-17-14-12
RTD-17-4
19.77
RT-17-7
11.24
0.023
RQ-17-4-1 to RQ-17-4-8
RTD-17-5
8.2
RT-17-8
20 54
0.013
RQ-17-15-1 to RQ-17-15-12
RTD-17-6
21 84
RS-17
RT-17-9
16 32
0.023
RQ-17-5-1 to RQ-17-5-13
RTD-17-7
11.24
RT-17-10
20
0018
RQ-17-16-1 to RQ-17-16-12
RTD-17-8
20 54
RT-17-11
25.94
0.022
RQ-17-6-1 to RQ-17-6-18
RTD-17-9
16.32
RT-17-12
19 89           0.029
RQ-17-17-1 to RQ-17-17-11
RTD-17-10
20
RT-17-13
27 45
0022
RQ-17-7-1 to RQ-7-17-23
RTD-17-11
25 94
RT-17-14
19.64
0.031
RQ-17-18-1 to RQ-17-18-14
RTD-17-12
19 89
RT-17-15
37.44
0 023
RQ-17-8-1 to RQ-17-8-28            RTD-17-13
27 45
RT-17-16
20.77
0042
RQ-17-19-1 to RQ-17-19-14
--------------------------------------- -
RTD-17-14
19.64
RT-17-17              25 48
0.024
RQ-17-9-1 to RQ-17-9-17
,
RTD-17-15
37.44
RT-17-18              21.54
0.029
RQ-17-20-1 to RQ-17-20-14
RTD-17-16
2077
RT-17-19
21 15
0.024
RQ-17-10-1 to RQ-17-10-14
RTD-17-17
2548
RT-17-20
21.63
0.024
RQ-17-21-1 to RQ-17-21-14
RTD-17-18
21.54
RT-17-21
14.00
0020
RQ-17-11-1 to RQ-17-11-10
RTD-17-19
21.15
RT-17-22
18.11
0.016
RQ-17-22-1 to RQ-17-22-14
RTD-17-20
21 63
Total
414 75
___________________________________________________ ___ ______________ 16 Water Works Design & Supervision Enterprise
In Association with Intercontinental Consultants and Technocrats Pvt. Ltd.'i • ii i 4 <Arjo-Dedessa Irrigation Project
Irrigation & Drainage
1.7 Water Quality for Irrigation
May 2007
Three samples  of water from Dedessa river from different sites  namely  dam site, Bridge on Bedele - Nekemte road and the bridge near Dembi (Jimma Bedele road) were collected and were analyzed at the WEDSE laboratory  Addis  Ababa for their physical and chemical characteristics.
These tests  were conducted to find out the turbidity, total solids, dissolved solids, Electrical conductivity, PH ammonia, sodium, potassium, magnesium, manganese, fluoride, chloride, bicarbonate, sulphate and phosphates. The results  of these tests  are available at Table 1.7. This  shows  that PH of water is  about 6.7, which is  within the limit, similarly  total dissolved solids  are between 60 and 90 mg/l, which is  within the permissible limit of 300 parts  per 100,000 parts  of water. The percentages  of calcium, magnesium, and sodium are 12, 3.6, 5.6 mg/l respectively  which are within permissible limit of 40 to 60 parts, 20 to 40 parts  and 10 parts  per 100,000 parts  respectively. These results  indicate that the water is suitable for irrigation purposes.
Table 1.7: Selected Physio-Chemical and Bacteriological Water Analysis Results for Dedessa
River
River at dam
site
River bridge on Bedle-Nekemte Road
River at bridge near
Dembi (Jimma
Bedie) Road
Date
14.5.06
15.5. 06
Turbidity (NTU)
26.0
43.0
25.0
Total solid 105^c(mg/l)
122.0
160.0
114.0
T. Dissolved solid 105°c(Mg/l)
78.0
90.0
60.0
Electrical conductivity (Us/cm)
102.0
120 0
84.0
p"
6.68
6.83
6.76
Ammonia ( mg/l NH3)
0.59
0.888
0.56
Sodium (Mg/l Na)
5.8
71
4.0
Potassium (mg I K )
3.4
3.8
2.4
Total Hardness (mg/l Ca CO )
3
44.00
50.6
44.0
Calcium (mg/l ca)
13.4
“14.2
10.7
Magnesium (mg/l Mn)
2.7
3.8
4.3
Total Iron (mg/l Fe)
0.34
0.51
0.38
Magnesium (mg/l Mn)
0.1
0.209
0.1
Fluoride (mg /1 F)
1.43
0.84
Trace
Chloride (mg/l C1)
2.9
2.9
1.9
Nitriet (mg/l NO2)
-
-
Nitriet (mg/NO2)
0.65
0.86
0.3
Alkalinity (mg/l CA CO3)
47.3
54.8
39.7
Carbonate (mg/l CO3)
Trace
Trace
Trace
Bicarbonate (mg/1 HCO3)
57.6
66.9
48.4
Sulphate (mg/l SO4)
8.8
14.3
8.2
Phosphate (mg/l PO4)
0.062
0.082
0062
SAR
0.38
0.43
0.26
17
Water Works Design & Supervision Enterprise
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lh !lArjo-Dedessa Irrigation Project
Irrigation & Drainage
2 CROP WATER REQUIRMENT & CANAL CAPACITY 2.1 INTRODUCTION
May 2007
The calculation of crop water requirement is  a very  important aspect for planning of any irrigation project. Several methods  and procedures  are available for this. The Food and Agriculture Organization (FAO) of the United Nations  has  also made available several publications on this subject and other issues related to this.
2.2 Procedure for Calculation
As recommended in FAO Publications three steps are involved in the calculation of the crop
water requirement.
(i) Calculation of Reference Evapotranspiration (ET )
O
The crop water requirement is  dependent on the meteorological factors, and Reference Evapotranspiration (ETO) presents  the effect of meteorological factors. The following Meteorological factors  are taken into consideration for calculation of Reference Evapotranspiration by  Modified Penman Method (FAO I & D paper No. 24) & Penman Montieth Approach (FAO I & D paper No. 46):
Temperature
Relative Humidity
Wind velocity
Sunshine hours
(ii) Selection of values for crop coefficient
The effect of crop on its  water requirement is  represented by  crop co-efficient (Kc). This  is presented by  the relationship between Reference Evapotranspiration (ET0) and crop
evapotranspiration  ETcrop   or  ETC   as  ETcrop
C      O.  The  values  for  crop  coefficient  vary  with =  K ET
the  crop,  its  stage  of  growth,  growing  season  and  prevailing  water  condition.  The  second step is required to select suitable values for crop coefficient.
iii) Effect of agricultural practice and local conditions
This  requires  evaluating  the  effect  of  climate  and  its  variability  over  time  &  space.  This  also requires to evaluate the effect of soil water availability and agricultural & irrigation practices
The three steps as enumerated above will be able to give the crop water requirement during its  crop period at monthly  i nterval. This  requirement will be in the field. Therefore, the losses  in the irrigation system have to be incorporated to arrive at the water requirement at the head of the irrigation system.
________ _____________________________________________________ _ ____________ ___ 18
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AArjo-Dedessa Irrigation Project
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2.3 Sources of Climatic Data
May 2007
There are three observation stations  for recording climatic  data near by  the project area. These meteorological stations  are located at Bedele, Jimma and Diddessa. While, Bedele observation station does  not have wind speed, Diddessa observation station does  not have records  of sunshine. Thus, Jimma observation station is  the only  station, where recorded data for all climatic  factors  are available for sufficiently  long periods. The climatic  data measured at this  station are rainfall, temperature, relative humidity, sunshine hours  and wind speed. The climatic  observation station at Jimma has  very  long and reliable records  of climatic  data. But the observation station located at Bedele is  closer to the command area. However, there is  elevation difference between observation station at Bedele and command area. Therefore, the climatic  data of Jimma and Bedele have been used for calculation of Reference Evapotranspiration (ET0) after adjusting the same for elevation difference. The summary  of the Meteorological characteristics  computed for the project area is  given in Table 2.1.
Table 2.1 - Summary of Meteorological Characteristics of the project area
Jan
Feb           March
Monthly r Mean Ten  iperature
April
in °C
May         June      July         Aug       Sept       Oct           Nov            Dec
Average 21.9 23.15 25.4 25.05 24.03 22.09 21.32 21.19 21.83 22.35 22.144 19 99 Min 19.5 20.44 23.63 16 26 15.89 20.96 19.99 19 88 21.06 20.19 19.081 16.92 Max 24.6 24.9 27.37 27.72 26.19 23.41 22.72 22.34 23.2 24.25 25.051 22.88
Relative Humidity (%)
Average 64.77 58.97 56.63 67.97 75.72 81.07 87.46 88 52 88.63 84.55 79.366 72.44 Min 51.5 43.2 45.09 57 42 65.23 65.8 61.77 72.23 82.49 74 24 67 667 55.37 Max 77.3 71.68 64.08 82 17 86.18 90.3 98.1 97.53 95.67 94.73 93.187 85 13
Wind Speed (m/s)
Average       0.62           0.8             1.0              1.08      1.04         0.86       0 62         0.51       0.5          0.51          0.48            0.51
Min              0.62           0.8             1.0              1.08      1.04        0.86        0 62         0.51       0.5          0.51          0.48            0.51
Max             0.62           0.8             1.0              1.08      1.04         0.86       0.62         0.51       0.5          0.51          0.48            0.51
Sunshine Hours (hrs/day)
Average 8 155 7.638 7.452 7.287 7.624 6.061 3.703 4.059 6.164 7.855 8 3245 8 306 Min 6.05 4.905 4.592 3.304 5.428 3.364 2.277 1.6 2 622 5.778 0.1121 6.634 Max 10 9.919 9.744 9.44 10.15 8.12 5.445 6.2 9.12 10 08 10.201 11.02
2.4 Estimation of ETo
ET0 has  been calculated by  the Modified Penman-Monteith method on a monthly  basis using estimated climatological data for the p roject a rea for each month of the year from 1961 to 2004. These have been calculated by  Penman-Monteith Approach with computer programme available in FAO I & D paper No 46. These values  for the mean monthly  are available in Table 2.2. From these values the average ETO as well as 75%, 80% and 90%
_____ ____________________________.____________________________________________ 19 Water Works Design & Supervision Enterprise
In Association with Intercontinental Consultants and Technocrats Pvt. Ltd.lAJfcJJiK.ll l> I 'IArJoDedessa Irrigation Project Irrigation & Drainage
May 2007
dependable ET0 have been calculated based on non-exceedance probability as shown in Table 2.3. ET0 has also been calculated on the basis of average monthly climatic data for the period of 1961-2004. The average monthly values of ET0 derived from the monthly values of ET0 calculated for each month for every year of record and those calculated on the basis of average monthly climatic data tally very closely. 75% dependable values of ET0 based on non - exceedence probability have been selected for planning.
20
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Table 2.2 : Estimated Monthly ETo of Arjo-Diddessa Project Area (in mm/month)
May 2007
Year
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003 12004
Jan    | Feb | March | April    May   June   July Jtugj    Sept   Oct   Nov    Decjf Annual 116     110     139      128     116     109   94.2   110    133   132   116     100         1403
100     105     144      130     137    105   81.6   77.4    112    112   104     99         1308
108     104     145      103     104    93.2     84    92.9    109    124   127     110        1303
122     117     144      140     140     104    84.3   86.6    116    132   116     119        1420
119     116     150      128     137     89     96.2   106    124    120   118     107        1410
114     118     138      142     135    102   95.1   93.1    111    134   123     104        1408
107     124     148      133     143    118    97.7   103    127    125   111     107        1444
109     114     140      139     127    111    81.4   89.9    108    111   122     105        1358
115     114     140      133     133     107   90.1   94.8    112    122   111      99         1369
124     124     157      137     148     120   99.4   99.7    122    125   107     102        1466
113     109     139      135     132    105   90.8   93.2    111    124   113     102        1366
120     122     140     151     135    106    105    102    125    131   126     104        1466
118     120    151      148     152    115   87.2   95.9    119    134   120     104        1464
111     117     140      127     143     105    102    102    109    126   58.6    104        1346
118     120     144      130     127     99     84.7   75.7     96     120   109     108        1332
116     123     144      143     125    111    90.8   94.8    105    115   104     105        1375
105     108     135      135     132     104     90      96     113    120   116     109        1362 119     101     144     141     136     107     80    94.2    106    116   114     100        1359
104     109     130     131     126    101    81.9   95.3   98.9   109   109     104        1299
102     102     130      132     134     107    90.9   94.5    111    123   110     107        1343
117     119     124      124     137     106   90.1   99.2   86.5   113   120     102        1338
112     105     144      129     128     113    92 3   92 5    116    120   105     102         1358
110     116     141      143     129     122    106     94     108    115   115     103        1401
111     121     146     151     127     107   97.4   96.6    116    133   120     107        1432
116     113     142      131     122     106   84.1   87.1    109    120    116     103         1349
106     110     134      121     131    91.3   88.2   95.6   96.5    118   120     107        1320
114     116     134      142     119     105    101     98     122    124   115     123         1412
117     118     156      145     142     113    84.2   103    108    129   121     108        1443
115     117     137      132     144     115     92     105    113    126    112     100         1408
118     94.8    133      107     104    97.4   90.6    95     111    136   117     114         1318
117     113     137      129     118     112    94.8   111     135   131    115    96.4        1411
106     110     146      139     144     109    84.5   80 3    113    115   108     105         1360
110     105     145      129     132    96.4   84.4   94.3    110    127    117     105         1355
122     120     149      139     141     105    85.2   87.8    117    132    122     116         1437
122     121     154      130     140    89.4   96.4   109    126    122    118     111         1439
114      120     142      147     135     101    95.8    94      113    134   123     107         1425 117     124     153      134     144     122    100    107    132    134    117     119         1505 121     121     149      148     132     115    82.6   91 9    112    119   124     104         1419
114      114     145      137     135     109    92.4   96.3    115    127   111     106         1402
125      124     162      144     151     125    103    104    126    129    118     109         1518 117      118     144      139     137     110    92.4    98     115    130    118    111         1429 124      123     147      154     142     111    107    106    129    135    127     110         1515 116      126     153      145     157     117    88.2    98     122    139    126     112         1498 119      120     142      135     150     108    100    104    112    130   61.7    112         1393
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Table 2.3: Values of ETo for Arjo-Diddessa Irrigation project
May 2007
Jan
~Feb
Mar
Apr
May
Jun
Jul
Aug
Sept
Oct
Nov
Dec
Total
Average for 1961- 2004
ET0
Monthly
115
115
143
135
134
107
91.8
96.5
114
125
114
107
1397
Daily
3.7
4.11
4.62
4.51
4.33
3.58
2.96
3.11
3.81
4.03
3.79
3.44
75%.
Monthly
119
120
148
142
142
113
97
102
121
130
123
110
1436
Daily
3.83
4.29
4.79
4.74
4.57
3.77
3.12
3.28
4.04
4.19
4.09
3.56
80%
Monthly
120
121
150
144
144
114
98
103
123
131
125
111
1446
Daily
3.86
4.33
4.83
4.80
4.63
3.81
3.16
3.32
4.09
4.23
4.16
3.59
90%
Monthly
122
125
153
148
149
118
101
107
127
135
131
114
1471
Daily
3.95
4.45
4.94
4.95
4 79
3.93
3.27
3.44
4.24
4 34
4.35
3.67
ET0
based
on
average monthly climatic data
Monthly
114
114
142
134
133
107
92
96
113
124
114
107
1390
Daily
3.69
4.08
4.58
4.48
4.28
3.57
2.95
3.10
3.75
4.00
3.79
3.44
2.5 Cropping Pattern
The Project is  being planned for cultivation of cereals, pulses, oil seeds  and other horticultural crops. Therefore the crop water requirement has been calculated based on the proposed percentage of land allocated for the different crops. In order to get the best results, it is intended to increase the cropping intensity in phases. Phase - I and Phase-ll. In order to maintain the fertility of soil two crop rotations have been proposed. In phase-l the cropping intensity of 126 to 136% has been proposed, which are available in Table 2.4 (a) and 2.4 (b) and illustrated in Fig 2.1 (a) and 2.1 (b) for Rotation 1 & 2 respectively. In Phase - II- the cropping intensity  will increase in the range of 156 to 173%, which are available at Table 2.5 (a) and 2.5(b) and illustrated in Fig 2.2 (a) and 2.2 (b) respectively
22
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Table 2.4 (a): Cropping pattern - distribution of area under Phase-1 (Crop Rotation - 1)
s.
No
Crop
Percent area under crop
Wet
Dry
Total for a
year
1
Maize
20
15
35
2
Rice
30
-
30
3
Wheat
-
15
15
4
Oilseeds
05
05
10
5
Pulses
05
05
10
6
Vegetables
05
05
10
7
Perennial       forage and grasses
03
03
06
8
Perennial         fruits trees and coffee
05
05
10
Total
73
53
126
Table 2.4(b): Cropping pattern - distribution of area under Phase-I (Crop Rotation 2)
s.
No
Crop
Percent area under crop
Wet
Dry
Total for a
year
1
Maize
20
25
45
2
Rice
30
-
30
3
Wheat
-
15
15
4
Oilseeds
06
05
11
5
Pulses
06
05
11
6
Vegetables
05
05
10
7
Perennial       forage and grasses
03
03
06
8
Perennial         fruits trees and coffee
05
05
10
Total
75
63
138
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Table 2.5(a) : Cropping pattern - distribution of area under Phase- II (Crop Rotation 1)
s.
No
Crop
Percent area under crop
Wet
Dry
Total    for    a year
1
Maize
20
20
40
2
Rice
45
-
45
3
Wheat
-
25
25
4
Oilseeds
05
05
10
5
Pulses
05
05
10
6
Vegetables
05
05
10
7
Perennial     forage     and grasses
03
03
06
8
Perennial fruits trees and coffee
05
05
10
Total
88
68
156
Table 2.5(b): Cropping pattern - distribution of area under Phase-II (Crop Rotation 2)
s.
No
Crop
Percent area under crop
Wet
Dry
Total for a
year
1
Maize
25
25
50
2
Rice
45
-
45
3
Wheat
-
30
30
4
Oilseeds
06
06
12
5
Pulses
05
05
10
6
Vegetables
05
05
10
7
Perennial     forage     and grasses
03
03
06
8
Perennial fruits trees and coffee
05
05
10
Total
94
79
173
24
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Fig. 2(a): Cropping Pattom*Pfcam II, (Crop rotational)
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Fig.1(b): Cropping Pattern-Phase I, (Crop rotation-2)
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2.5.1 Planting Dates and Crop Calendar
The planting dates of the various crops have been proposed by Agricultural Planning Group based on the local practices  and experiences. These are available in Table 2.6. The calculation of water requirement has been estimated based on these proposed types of crops and their cropping calendars.
2.5.2 Crop Coefficient (kc)
IQ is the experimentally derived crop coefficient that is presented to relate ET0 to crop
evapotranspiration (ETcrop  or ETC
= k ET ). For
c0
the given crop types and cropping patterns 
the  corresponding  kc   values  are  selected  from  FAO’s  publications  and  other  literatures available on the subject and the monthly ETC for the respective crops has been computed.
Table 2.6 CROP CALENDAR FOR
SI.
no
Wet season crops
Dry season crops
Name of
crop
Crop calendar
Crop
Period
Name of crop
Crop Calendar
Crop
Period
1
Rice paddy (plantingdate) 25lbJune
Rice paddy
31 ' may to 12'" Oct
s
135 day
2
Maize
20 June to 15 Oct
mm
118days
Maize
7 Dec to 3^ Apr
,r
118days
3
Wheat
—
Wheat
251" Nov to 29* Mar
125 days
4
Groundnut
10lhJuneto 7'"Oct
120 days
Groundnut
16 Dec to 24'" Apr
lh
130 days
5
Sunflower
15th June to 27mOct
135 days
Sunflower
Pi^Dec to 15'"Apr
136 days
6
Sesame
20'" June to 25'"Sep
98 days
Sesame
1 s' Dec to 9thMar
99 days
7
Soya bean
15'" June to 27'"Oct
135 days
Soya bean
r'Dec to 15" Mar
8
Haricot bean
10'" June to 15'"0ct
135 days
128 days
Haricot bean
1 ’ Dec to 14 Apr
s                         ,r
135 days
9
Potato
“201" June to 17'"0ct
120 days
Potato
201" Nov to 24’Mar
s
125 days
10
Onion
1 ' July to 20'"Oct
112 days
Onion
16  Jan to 5 Apr
,n                    ,n
80 days
11
Cabbage
1 ' July to 30'"Sept
s
92 days
Cabbage
16'" Dec to 16'"Mar
12
Alfa-Al fa
1 'Nov to 31” Oct
s
365 days
91days
Alfa-Alfa
365 days
13
Hybrid Napier
1 ' June to 31 ' may
ss
365 days
365 days
Hybrid Napier
365 days91day
14
Citrus          & others
1 ' Oct to 30'"Sept
s
365 days
365 days
Citrus & others
365 days
365 days
15
Banana
1 'June to 31 ' may
ss
365 days
Banana
365 days
16
Coffee
1 ' Nov to 31 ' Oct
ss
365 days
Coffee
365 days j
365 days
365 days
Note: - The proposed percentage of cropped area vanes from season to season, dunng rotation under both phases-1 & II.
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2.6 Effective Rainfall
May 2007
The average annual rainfall in the command is around 1453 mm. The monthly rainfall data at the project area is available (for detail see hydrological report). The result of monthly average, 75% and 80% dependable effective rainfall is tabulated in Table 2.7.
Table 2.7: monthly averages and 75% & 80% dependable effective rainfall (in mm)
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sept
Oct
Nov
Dec
Total
Average rainfall
153
18.4
53.6
69.5
180.8
243.0
245.9
238 3
228.6
115.5
31.4
12.7
1453
75%.
3
2.6
20
29 9
82.6
116.1
132.2
127.3
125.6
47.4
10.2
2.2
699.1
80%
1.0
0.2
15.1
229
72.9
107.5
129.4
121.9
121.0
38.4
8.7
1.0
640
2.7   Calculation of Crop Water Requirement
Seventy five percent dependable monthly values of Reference Evapotranspiration (ET )
0
based on non- exceedance probability have been selected for calculation of crop water requirement.   Appropriate   values   for   crop   coefficient   have   been   used.   Accordingly calculation for crop water requirement has been made for all types of crops. The details of these calculations are given in Annex-VIII of Final Interim Report. The abstracts of the monthly crop water requirement based on the proposed cropping intensities for different crops have been prepared for each crop rotation under both phases. In these calculations, besides cropping intensities for different crops, the losses in the canal system have also been appropriately accounted for. Therefore,  these calculations give the gross monthly water requirement at the head of canal both in terms of depth of water in mm and in terms of litre per second per hectare. The abstracts of these calculations are available in Tables 2.8 (a) & 2.8(b) for the two rotations of Phase-I & in Tables 2.9 (a) & 2.9 (b) for the two rotations under Phase - II. The duty in terms of litres per second per ha is based on 24 hours running of the canals. The abstract of the gross monthly water requirement at head of primary canal for two rotations under Phase - I & II & are available in Table 2.10. The table shows the gross monthly water requirement both in terms of depth of water mm as well as duty in terms of litre/second/ha.
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Table 2.8 (a) CROP WATER REQUIREMENT Phase I Rotation I
May 2007
Unit in mm
Crop Type
Dale                        of transplantation
Cropped ar ea %
Irrigation
Efficiency
Jan
Feb
Mar
Apr
May
June
July
Aug
Sept
Oct
Nov
Dec
yoarly total
Wet
Dry
1
2
3
4
5
6
7
8
9
10
11
12
cerials
50
30
1
Rice
(Padd>)
25* June
(30)
50%
0 00
157 74
43 68
50 40
59 23
40 78
351 83
2
Maize
(20)
< 15>
40%
35 02
50 78
40 23
2 61
0 00
0 00
0 00
0.00
10 93
1596
3
44 40
155 53
Wheal
(15)
40%
48 53
29 33
2 93
24.75
149 94
Oil seeds
5
5
40%
4
Groundnut
(2)
(2)
3 78
5 15
6 40
3 35
0 00
0 00
0 00
0 00
0 64
1 22
20 54
5
Sunflower
(0 5)
(0 5)
1 11
1 62
1 69
0 66
0 00
0 00
0 00
000
0.55
5 63
6
Sesame
[251
(2 5)
7.62
7 19
0 71
0 00
0 00
0 00
0 00
4.61
20 13
Pulses
5
5
40%
7
Soya bean
(3)
(3)
8 16
10 16
9 93
2 93
0 00
0 00
0 00
0 56
2 34
4.30
38 38
8
Haricot bean
(2)
(2)
5 32
6 47
6.10
1 62
0 00
0 00
0 00
0 39
0 87
2 80
23 57
Vegetable
5
5
40%
9
Potato
(2)
(2)
5 68
6 41
4 10
0 00
0 00
0 00
0 19
1.45
0 83
3 25
21 91
10
Onion
(2 5)
(2 5)
1.82
7 11
8 46
0.95
0 00
0 00
0 00
0 47
2 54
21 35
11
Cabbage
(0 5)
(0 5)
1 24
1 54
0 80
0 00
0 00
0 00
0 00
031
3 89
Orchard
5
5
40%
12
Citrus & others
(0 5)
(0 5)
1 30
1 32
1 32
1 14
0 48
000
0 00
0 00
0 00
0 79
1 18
1 17
8 70
13
Banana
(2 5)
(25)
8 00
8 10
8 93
7 89
5 58
0 00
0 00
0 00
0 00
4 35
7 05
743
57 33
14
Coffee
(2)
(2)
6 40
6 47
7 14
6 32
3 68
0 41
0 00
0 00
0 38
4 78
6.26
5 91
4 7 75
Forage & others
18
19
Alfa-Alfa & others
3
3
40%
9 15
9 26                10 16
8 94
5.00
0 19
0 00
0 00
0 11
6 68
2 93
8 50
60 92
Crop intensity
73
53
126%
20
Total CWR (mm)
139.00
170.11
135 30
36.41
14.74
158 34
43.68
50.40
61.33
76.15
21.18
80.76
987.40
21
L/s/ha
0 520
0.703
0.505
0.140
0.055
0.611
0 163
0 188
0 237
0 284
0 082
0 302
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Table 2.8 (b) CROP WATER REQUIREMENT Phase I Rotation II
Crop Type
CERIALS
Rice (Paddy)
Maize
Wheat
Oil seeds
Groundnut
Sunflower
Sesame
Pulses
Soya bean
Hancol bean
Vegetable
Potato
Onion
Cabbage
Orchard
Citrus & others
Banana
Coffee
Forage & others
Alfa-Alfa & others
Crop intensity
Total CWR (mm)
Date
transplantation
of
Cropped area %
Irrigation
Efficiency
yearly total
351 83
251 59
149 94
21          L/s/ha
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Table 2.9 (a) CROP WATER REQUIREMENT Phase 11 Rotation I
May 2007
yearly total
Crop Type
Date
transplantation
of Cropped area %
Imqatron Efficiency
CE RIALS
Rice
(Paddy;
Maize
Wheat
Oil  seeds
Groundnut
Sunflower
Sesame
Pulses
Soya bean
Harcol bean
Vegetable
Potato
Onion
Cabbape
Orchard
Citrus & others
Banana
Co Hee
Forage & others
Alfa-Alfa & others
Crop intensity
Total CWR (mmj
L/s/ha
527 75
203 73
249 89
237.21
.
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Table 2.9 (b) CROP WATER REQUIREMENT Phase I, Rolelion I,
Crop Type
Date
transplantation
of
Cropped area %
Irrigation
Efficiency
yearly total
CERIALS
R»ce
(Paddy)
Maize
Wheal
Oil seeds
Groundnut
Sunflower
Sesame
Pulses
Soya bean
Haricot  bean
Vegetable
Potato
Onion
Cabbage
Orchard
Citrus & others
Banana
Coffee
Forage & others
Alfa-Alfa & others
Crop inlensrty%
Total CWR (mmi
L/s/ha
527 75
254 22
299 86
193.28
722
142 32 34
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Table 2.10 Gross water requirement at primary canal head (month wise)
May 2007
Phase
Rotation
Particulars
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sept
Oct
| Nov
Dec
Total
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
GCWR mm
139.00
170.11
135.30
36.41
14.74
158.34
43.68
50.40
61.33
76.15
21.18
80.76
987.40
1
l/s/ha
0.520
0.703
0.505
0,140
0.055
0.611
0.163
0.188
0.237
0.284
0.082
0.302
GCWR in mm
162.32
203.96
162.12
38.14
14.74
158.34
43.68
50.4
61.65
78.21
21.2
91.4
1086.14
I
2
l/s/ha
0.606
0.840
0.605
0.14
0.06
0 611
0.163
0 188
0 238
0.292
0 082
0.341
GCWR in mm
180.28
219.38
168.26
37.28
14.74
237.21
65.52
75.61
90.94
96.54
23.13
102.58
1311.47
1
l/s/ha
0.673
0.907
0.628
0.144
0.055
0.915
0.245
0.282
0.351
0.36
0.089
0.383
GCWR in mm
209.35
255.54
193.29
38.79
14.74
237.21
65.52
75.61
91.07
100.39
24.1
117.62
1423.234
II
2
l/s/ha
0.782
1.056
0.722
0.150
0.55
0.915
0.245
0.282
0.351
0.375
0.093
0.439
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2.8  Method of Irrigation
The manner in which water is  applied to crops  in the field is  known as  method of irrigation." There are three broad categories for method of irrigation - surface irrigation, sub-surface irrigation and sprinkler irrigation. While in surface irrigation water is applied on level either by flooding the surface or in furrows, wetting the surface either partly or fully, in sub-surface irrigation water is made available in the root zone of the crop by applying beneath ground through pipes. In sprinkler irrigation water is applied through artificial spray as in rainfall.
In this project surface irrigation method has been proposed. However, there are several methods  under surface irrigation also, which include Border strip (Graded Border) Method; Check Basin (Level Border) method; Basin for orchard (Ring) Method; contour Ditch Method; Level Farrow Method etc. The selections of suitable method of surface irrigations depends on several factors such as crop to be irrigated, characteristics of soil, topographical features etc.
Taking into consideration, the proposed cropping pattern and the prevailing soil characteristics and topographical features of land, “Check Basin" method of irrigation has been proposed to be adopted, which in considered most suitable.
2.9  Efficiency of Irrigation System
The gross requirement of water for irrigation system is very much dependent on the overall efficiency of the irrigation system, which in turn is dependent on several factors as given below:
•    Method of irrigation
•    Type of canal
Lined and /or
Unlined
•    Method of operations
Simultaneously & continuous, or
Rotational water supply
•    Availability of structures for
Controlling and distribution
Measuring & monitoring
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2.9.1   Efficiency for Unlined Canal System
In a view of available water, overall water requirement, economics  of lining and soil characteristics  i.e. texture and structure, the canal system has  been planned and designed as  unlined (earthen) channels. All the components  of canal system - from primary to quaternary and field and farm channels are unlined. In view of this, based on the experiences in this country and also in other countries of the world, it is assumed that the canal losses will vary between 35 to 40% of the discharge. Accordingly, it is proposed to adopt total canal loss from primary to field/farm channel of 37.5%. In other words the conveyance efficiency of irrigation system is 62.5%
2.9.2   Field Application Efficiency
Besides the losses in the canal system, loss also takes place in the field where water is actually applied to the crops. This is very much dependent on the method of irrigation and this in turn depends on several factors like type of crop, characteristics of soil and land, availability of water etc. In case of paddy, where water is applied to the standing pool of water already ponding in the field, the losses will be less and efficiency will be high. Its field application efficiency may vary from 0.75 to 0.85. Therefore, it is proposed to adopt a field application efficiency of 0.8 for paddy. In case of other crops, like wheat, maize, pulses oil seeds etc. the application efficiency will be less compared to that of paddy. It is proposed to adopt a field application efficiency of 0.65 for other non-ponded crops.
3.9.3   Overall Irrigation Efficiency
With the conveyance efficiency  of 62.5% and field application efficiency  of 0.80 for paddy and 0.65 for other non-ponded crops the overall irrigation efficiency will work out to 0.50 for paddy  (ponded) crop and 0.40 for other non-ponded crops. These assumptions are considered very appropriate for the situation prevailing in Arjo Dedessa Irrigation Project.
2.9.4   Measures for Improving Irrigation Efficiency
Though the proposed irrigation efficiency  of 0.50 for paddy  and 0.40 for other non ponded crops  is  considered very  appropriate and justified, in view of the very  low irrigation efficiency in existing irrigation schemes of Ethiopia and other countries of the world, it is  considered necessary  to incorporate measures  both under hardware and software categories in order to achieve even this moderate value of irrigation efficiency
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The measures under category of hardware include the layout and structures inherent in planning and design and these are as follows:
-    Structures for regulation of discharge without gate (proportionate distributor of flow)
-    Duckbill weir for maintaining full supply level
-    Modular outlet for delivering equitable water to fields,.
The measures under the category of software include measures under operation and water management and are as given below:
•    Rotational water supply at macro-level
•    Regulating supply as per irrigation schedule
•    Introduction of irrigation schedule
•    Rotational water supply at micro-level
-    turn - by - turn
-    for fixed duration
2.9.5 Participatory Irrigation management (PIM)
Participation of farmers in the management of irrigation system particularly at lower level i.e., at level of quaternary and tertiary canals is considered as an important measure for improving the efficiency and quality of irrigation system. In order to involve the farmers in operation and the management of the irrigation in an effective manner, it is essential that they should be involved right from the beginning i.e., planning stage particularly planning at micro level. However, for this farmers may have to be organized and an appropriate institutional organization will have to be developed. This will require good deal of endevour to organize and train the farmers for adopting PIM It is proposed to introduce PIM in Arjo-Dedesa Irrigation Project in view of role it is expected to play in improving the efficiency and equality of irrigation system.
2.9.6 Losses in Different components of Canal system
Losses in the different components of unlined canal system will vary from the primary to quaternary /field canals depending on its capacity, length and type of soil encountered through its alignment. In the planning process the loss in the different reaches of the primary canal will be calculated and accounted for according to the standard procedure of assessing seepage loss on the basis of wetted perimeter. The unit loss per million- wetted perimeter will be adopted in the light of experience in other projects in Ethiopia _________________________________________________________ __________ 38
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and other countries. The losses  in other components  like secondary, tertiary  and quaternary will be assumed in terms of percentage of discharge. It is proposed to adopt the efficiency of different components canal system as given below in Table 2.11 for the preliminary planning and design.
Table 2.11 Efficiency for Different Components of Canal System
Efficiency
Component
Individual
Cumulative
Primary
0.925
0.925
Secondary
0.925
0.856
Tertiary
0.90
0.77
Quaternary
0.90
0.69
Field/Farm canal
0.90
0.625
Over all
0.625
The losses in different components have been distributed tentatively in the light of past experiences to facilitate the design of different components keeping in view the over all conveyance efficiency of 0.625.
2.10  Peak Design duty at the head of Primary canal
The peak  requirement in terms  of duty  litres/sec/ha for proposed crops  and their intensities for all the two rotations under both the phases are given in Table 2.12. The figures in this table show that the peak duty for Phase-I varies between 0.703 to 0.840 litre per second per hectare and for Phase-ll, it varies between 0.915 to1.056 litre per second per hectares. Thus the Primary Canalswill be designed with a peak duty at head of 1.056 liter per second per hectares.
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Table 2.12: Peak duties for different crop rotations under Phase-1 & II
Phase
Rotation
Annual CWR in
mm
Monthly max.
CWR in mm
Max.
US/ha
Month
Crop
intensity %
1
987 40
170.11
0.703
Feb
126
I
2
1086.14
203.96
0.840
Feb
138
1
1311.47
237.21
0.915
Jun
156
II
2
1423.23
255.54
1.056
Feb
173
However the secondary canals will be designed with a peak design duty of 0.9768 litre/ second/ ha taking into consideration the losses  in the Primary  canal. Similarly the tertiary canals will be designed with a peak duty of 0.9035 litre/second/ ha taking into consideration the losses  in secondary  & primary  canals. This  is  based on 24 hours running of the canals. This is based on 24 hours running of the canals.
2.11 Flexibility Factor for the Main Canal
In order to meet any change in future as well as for providing flexibility in operation like adopting rotational water supply, it is proposed to increase the design discharge of all the components  of the irrigation system. Based on the convention used in other projects, it is proposed to adopt the flexibility factors as given below in Table 2.13.
Table 2.13: Flexibility Factor for different components of Canal system
Component
Flexibility Factor
Primary Canal Secondary Canal
Tertiary Canal
Quaternary Canal
10%
15%
20%
25%
Since  the  channels  with  higher  discharges  have  more  capability  to  adjust  with  the changes, smaller flexibility factors have been adopted for them and vice versa.
2.12  Monthly Water Requirement from Dam Site
For the purpose of planning and simulation study, the water requirements for two sets of crop rotations for both Phase I & II have been assessed in terms of mm & Mm . These are available in Table 2.14 (a) & 2 14 (b) respectively.
3
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2.13 Irrigation scheduling & Water management
May 2007
This may be noted that the actual irrigation will be carried out according to the irrigation schedule to be worked out on the basis of stage of crop development, prevailing climatic data and water management practices proposed to be adopted during actual operation of the canal system. For this there is enough scope and sufficient flexibility has been provided in the system.
Table 2.14 (a) Depth of Water for various Scenarios (mm)
Phase 1
Phase II
Roti
Rot2
Roti
Rot2
mm
l/s/ha
mm
l/s/ha
mm
l/s/ha             mm
l/s/ha
Jan
139.00
0.52
162.32
0.606
180.28
0673
209.35
0.782
Feb
170.11
0.703
203.96
0.840
219.38
0.907
255.54
1.056
Mar
135.30
0.505
162.12
0.605
168.26
0.628
193.29
0.722
Apr
36.41
0.140
38.14
0.140
37 28
0.144
38.79
0.150
May
14.74
0.055
14.74
0.060
14.74
0.055
14.74
0.55
Jun
158.34
0.611
158.34
0.611
237.21
0.915
237.21
0.915
Jul
43.68
0.163
43.68
0.163
65.52
0.245
65.52
0.245
Aug
50.40
0.188
50.4
0.188
75.61
0.282
75.61
0.282
Sep
61.33
0.237
61.65
0.238
90.94
0 351
91.07
0.351
Oct
76.15
0.284
78.21
0.292
96.54
0.360
100.39
0.375
Nov
21.18
0.082
21.2
0.082
23.13
0.089
24.1
0.093
Dec
80.76
0.302
91.4
0.341
102.58
0.383
117.62
0.439
Total
987.4
1086.16
1311.47
1423.23
Crop
intensity %
126
138
156
173
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1
Table 2.14 (b) Volume of Water for Various Scenarios (Mm ) for 13665.27 ha Command Area
Phase I
Phase II
Roti                             Rot2
Roti
Rot2
Jan
18.995
22.181
24.636
28.608
Feb
23.246
27.872
29.979
34.920
Mar
18.489
22.154
22.993
26.414
Apr
4.976
5.212
5.094
5.301
May
2.014
2.014
2.014                                 2.014
Jun
21.638
21.638
32.415
32.415
Jul
5.969
5.969
8.953
8.953
Aug
6.887
6.887
10.332
10.332
Sep
8.381
8.425
12.427
12.445
Oct
10.406
10.688
13.192
13.719
Nov
2.894
2.897
3.161
3.293
Dec
11.036
12.490
14.018
16.073
Total
134.931
148.427
179.216
194.488
3. HYDRAULIC DESIGN OF CANALS
3.1 Introduction
The prime objective of the network of the canal system, comprising various components from Primary  to Quaternary  canals, is  to supply  irrigation water for growth and development of different types of crops so that optimum production is achieved. It is, therefore, very essential that the different components of the canal system should be able to carry adequate discharge which may be able to meet the needs of proposed crops  under the command of individual components. In this  context, the following issues are very relevant.
-  The layout of canal system
-  Crop water requirement
-  Efficiencies of different components of canal system
It may be noted that these issues have already been discussed in previous sections of the report. The canal capacities, for which hydraulic designs have been made, are based on 24 hour running of canals.
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3.2 Design Criteria
The detailed criteria for the hydraulic design of unlined canals have been prepared and furnished in the “Criteria for Planning & Design of Irrigation system vide Annex - V of Final Interim Report: Vol. VI. The hydraulic design of irrigation channels has been done accordingly.
3.3 Design of unlined Irrigation channels
In view of the fact that water is available in adequate quantity and there is no scarcity of water, the irrigation system has been planned and designed as unlined canal and the hydraulic  design of the different components  of irrigations  system have been done accordingly. In this context the prime consideration is that the channel should be non silting and non-scouring i.e. the channel should be hydraulically stable. Accordingly the important parameters  related to hydraulic  design of an unlined channel have been selected as discussed below:
i) The discharge passing in an open channel has been calculated by the continuity formula
Q = AxV
Where Q = discharge in m /sec
A = area of the cross section of the canal in m2
V = mean velocity of flow in m /sec
The velocity has been calculated by Mannings formula
Where, V = Mean velocity of flow in m/sec
n = Rugosity co-efficient
s = Slope of water surface
R= Hydraulic mean radius (R = A/P)
P= Wetted perimeter in meter
A= Cross-section of the canal in m2
ii)  Rugosity Co-efficient
The value of rugosity co-efficient (which is denoted by ‘n’) varies according to physical roughness of the side and bottom of the channel and it also depends on discharging capacity of the channel Based on experience and general practice the following values of 'n' have been adopted.
3
3
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For Primary Canal (equivalent to distributary)
n = 0.0225
For secondary Canal (equivalent to minor)
n = 0.025
For Tertiary (equivalent to watercourse)
n = 0.025
For Quaternary (equivalent to field channel)
n = 0.025
iii) Permissible Velocity
With a view to achieve a non-scouring & non-silting velocity  and taking into consideration the prevailing black  cotton soil and similar soil as  bed material, a permissible velocity of 0.6 m/sec to 0.9 m/sec has been selected as
iv) Longitudinal slope
The longitudinal slope plays  very  import role in generating velocity. The longitudinal slope of any  irrigation channel will depend on the topographic  features  and available natural slope. It will also depend on the discharging capacity  of the channel. For channels  having higher discharge comparatively  mild slope will be able to generate higher velocity  where as  in case of lower discharge slightly  steeper longitudinal slope will be required to get the desired velocity. A longitudinal slope of 0.02 per % has been adopted for the primary  canals, in the head reaches, which has  been increased subsequently in the end to 0.03 per %. It may be noted that primary canals are contour canals, hence the alignment has been adjusted to get the required slope and no drop has been required.
A longitudinal slopes of 0.025 to 0.03 % has been adopted for secondary canals, which has  been aligned on ridges. Where ever the natural slope is  more steep, drops  have been provided suitably  to adjust the natural slope. Tertiary  canals  also have been aligned along the contour. Accordingly  a slope of 0.033 to 0.04% has  been adopted. The capacity of quaternary canals has been kept the same as the parent tertiary canal. But the quaternary  canals  are aligned along the slope. Therefore a suitable slope has been adopted to keep the velocity within required limit and falls have been provided to adjust additional drop
v) Bed width and Depth Ratio
The experiences  of unlined irrigation channels  in alluvial soils, which have remained stable - non-scouring a nd non-silting over y  ears-have shown the existence of certain ratio between bed width and depth. A graph sharing the relation between the bed width depth ratio and discharge of the channel has been provided for guidance vide Fig. 1.0 of
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Annex — VI —  u Criteria for Planning & Design of Irrigation & Drainage System” under Final Interim Report. While finalization of the hydraulic  design of the canal system, information in this figure has been utilized for guidance.
vi)  Critical Velocity Ratio
The critical velocity, which has been defined by Kennedy as velocity prevailing in non silting and non-scouring channel in study require, has also been calculated according to Kennedy  equitation and the critical velocity  ratio has  also been checked for its appropriateness.
3.4 Hydraulic Particulars of Canal System
Based  on  the  above  discussion  the  hydraulic design of different components of canal system has been finalized. These are available in the report as indicated below:
i)  Right Primary Canal             -      Table  3.1
ii)  Left Primary Canal              -      Table  3.2
iii) Secondary canal-RS-16 -            Table 3.3
iv) Secondary Canal RS-17 -           Table 3.4
v) Tertiary canals under RS-16 -      Table 3.5
vi) Tertiary canals under Rs-17 -      Table 3.6
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Table 3.1: - Hydraulic Particulars for Right Primary Canal
Rogosity coefficient (Manning's n = 0.0225)
Canal side slope (1.5:1 for cut & 2:1 for fill)
May 2007
SI. no
Cumulative
Distance in
km
Main canal
progressive
discharge of
the
Bed
width
(m)
Bed
level
(m)
F.S.D
(m)
Velocity
(m/s)
Canal bed
slope
Critical velocity Vo
m/s 
0 54
=0 546D
v/v0
Free
board
(m)
00
. RS 1
0.0
7.521
6.25
1.4
0.643I
0.0002
0.6772
0.950'
0.70
- RS-2
0.555
7464
6.25
1.39
0.639)
0.0002
0.677
0.948
0.70
1.692
7.358
6.25
1.38
0.637
0.0002
0.674
0.949
0.70
RS-3
2.951
7.298
6.25
1.38
0.635
0.0002
0.671
0.946
0.70
RS-4
4.142
7.228
6.25
1.37
0.633
0.0002
0.671
0.948
0.70
RS-5
4.887
7.127
6.25
1.36
0.632
0.0002
0.668
0.951
0.70
RS-6
5.750
7 087
6.25
1.35
0.630
0.0002
0.665
0.952
0.70
RS-7
6.123
7 030
6.25
1.35]
0.629]
0.0002
0.662
0.951
0 70
RS-8
10.14
6.973
6.25
1.34
0.627
0.0002
0.662
0.952,
0.70
RS-9
10.97
6 925
6.25
1.34
0.624
0.0002
0.658
0.948
070
RS-10
12.382
6.803,
6.25
1.32
0.625
0.0002
0.658
0.958,
0.70
RS-11a
15.010
6.658
6.
1.33]
0.62
0.0002
0.6553
0.950
0.70
RS-11b
15.010
6.576
6
1.33
0.624
0.0002
0.6553
0.952
0.70
RS-12
16.393
6.447
6
1.31
0.617
0.0002
0.6490
0.951
0.70
RS-13
17.186
6.315
6
1.30
0.610
0.0002
0.6458
0.945
0.70
RS-14
17.756
6.207
6
1.28
0.610
0.0002I
0 6395
0.954
0.70
RS-15
18.8841
5.981
6
1.261
0.604
0.0002
0.6330
0.954
0 70
RS-16
21.327
5 523
5.5
1.25
0.596
0 0002
0.6298
0.946
0.70
RS-17
21.788
4.969
5
1.24
0.584
0.0002
0.6266
0.932
0.60
RS-18
22.762
4.78
5
1.21
0.578
0.00022
0.6168
0.937
0.60
RS-19
23.797
4.524'
5
1.18
0.569
0.00022
0.6070
0.937
0.60
RS-20
24.842
4.249
4^5
1.16
0.5852
0.00022
0.6004
0.975
0.60j
RS-21
26.347
4.043
4.5
1.13
0.576
0.00022
0.5904
0.976
0.60
RS-22
28.063
3.863
4.01
1.13
0.603
0.00025
0.5904
1.021
0.60
RS-23
28.868
3.77
4.0
1.11
0.565
0.00025
0.5837
0.968
0.60
RS-24
29.761
3.683
4.0
1.10
0.595
0.00025
0.5803
1.025
0.60I
RS-25
30.285
3.644
40
1.09
0 593
0.00025
0.5770
1.028
0.60
RS-26
31.332
3.52
3.8
1.09
0.594
0.00025
0.5770
1.030
0.60
RS-27
31.836
3.234
3.5
1.08
0.581
0.00025
0.5736
1.013
0.60
RS-28
32.960
3.188
3.5
1.08
0.578
0.00025
0.5736
1.008
0 60
RS-29
33.818
2.99
3.5
1.04
0.568
0.00025
0.5599
1.015
0 6')
RS-30
34.819
2.33
2.6
1.03
0.543
0.00025
0.5564
0.976
0.60
RS-31
35.218
2.044
2.5
0.98
0.525
0.00025
0.5390
0.974
0.50
RS-32
35.922
1.802
2.2
0.97
0.508
0.00025
0.5355
0.949
0.50
RS-33
36.475
1.649
2
0.96
0.501
0.00025
0.5319
0.942
0.50i
RS-34
37.418
1.51
2
0.91
0.49
0.00025
0.5140             0.953
0.50
RS-35
38.537
1.41
2
0.88
0.481
0.00025
0.5031
0.956
0.50
RS-36
39.556
1.199
1.5
0.87
0.49
0.00025
0.4994
0.981
0.50
RS-37
40.207
0.994
1.5
0.79
0.466
0.000285
0.4695
0.992
0.50
RS-38
42.088
0.735
1.3
0.72
0.433
0.000285
0.4425
0.979
0.50
RS-39
43.109
0.624
1
0.72
0.418
0.000285
0.4425
0.945
0.50
RS-40
44.166
0.563
1
0.68
0.407
0.000285
0.4266
0.954
0.50
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le 3.2: Hydraulic Particulars for Left Primary Canal
Rogosity coefficient (Manning's n = 0.0225)
Canal side slope (1.5:1 for cut & 2:1 for fill)
May 2007
Sl.no
Cumulative Distance in
km
Main     canal progressive
discharge
Bed
width
(m)
Bed
level
(m)
FS.D
(m)
Velocit
y (m/s
Canal bed
slope
Critical
velocity Vo
O.546D064
m/s
C.VR
= V/Vo
Free
board
(m)
Perimeter
(m)
Reach
length
(m)
Discharge
0
0 00
9.015
75
1.42
0 664
0.0002
0.683        0 972            0 70
12 62
0.00
1
0 20
8.968
7.5
1.41
0.662
0.0002
0.680       0 973
0.70
12 584
200
2
3 10
8.931
7.5
1 41
0 661
0 0002
0680
0 972
0.70
12.584
2900
3
3 70
8.886
7.5
1.4
0 66
0 0002
0.677
0.975            0.70
12.548
600
4
4 60
8 863
7.5
14
0 659
0.0002
0.677
0.973           0.70
12.548
900
5
5 30
8 818
7.5
1.4
0 658
0 0002
0.677
0.972           0 70|
12.548
700
6
6 00
8 746
7.5
1 39
0.657
0 0002
0.674
0 975            0 70
12.512
700
7
660
8.701
7.5
1.39
0 656
0.0002
0.674       0 973           0 70|
12.512
600
fl
9 95
861
7.5
1.38
0.655
0.0002
0.671
0.976            0 70
12476
3350
9
10 51
8 455
7.5
1.36
0.649
0.0002
0.665
0.976
0.70
12.404
560
10
13.891
8.32
7.5
1 36
0.647
0 0002
0.665
0 973
0 70
12 404,
3380
11
15 76
8 275
7.5
1.35
0.645
0 0002
0.662
0 975
0.70
12 367
1870
12
20 17
8 198
7.5
1.34
0.643
0 0002
0.658
0 976
0.70
12.331
4410
13
20 77
8 12
7.5
1.33
0 641
0 0002
0.655
0 978
0.70
12 295
600
14
21 97
I8.062
7.5
1.33
0 639
0 0002
0655       0.975           0.70
12 295
1200|
15
23 15
7 663
7
1 34
0.636
0 0002
0.658
0 966           0 70
11 831
1180
16
23 59
7 587
7
1.33
0.634
0.0002I
0.655
0 967           0.70|
11 795
440
17
26 65
7.413
7
1 33
0.63
0.0002
0 655
0 961
0.70|
11 795
3060
18
27 36
7.334
7
1.30
0.628
o.ooo2
0.646
0 972
0.70
11.687
710
19
2862
7 292
7
1.30
0 627
0 0002
0 646       0 971
0.70
11 687
1260
20
2930
7 267
7
1.30
0 627
0 0002
0.646       0.971
070
11 687
680
21
30 13
7 219
7
1 29
0 625
0.0002
0 643       0 973           0.70
11 651
830
22
30 84]
7.0581
7
1.28
0 62
0 0002
0 639
0.970           0 70
11 615
710
23
32 16
6 378
6
1.27
0.636
0000222
0.636
1 000
0.70
10 579
r 1320
24
33.61
6 262
6
1 26
0 633
0 000222
0.633       1.000
0 70
10 543
1450
25
34.94
6 164
6
1.25
0.625
0.000222
0 630       0 992
0 70
10 507
1330
26
36 05
5 322
5
1.25
0.617
0.000222
0 630       0.980            0 60
9 5069
1110
27
37 08
5.286
5
1.25
0.616
0.000222
0.630       0 978           0 60
9 5069
1030
28
38 43
5 265
5
1.25
0.615
0.000222
0.630       0 976           0 60
9 5069
1350
29
39 26
5231
5
1 24
0.614
0.000222
0 627
0 980
0 60
9 4709
830
30
40 10
5.161
5
1 23
0612
0 000222
0 623
0 982
0.60
9 4348
840
31
40.45
5.125
5
1 23
0 61
0 000222
0 623
0.979           0 60
9 4348
350
32
41 09
5 013
5
1.21
0 606
0.000222
0617       0 982           0 60
9 3627
640
33
4224
4 897
5
1 20
0.602
0.000222
0.614       0 981            0.60
9 3267
1150
34
44 56
4 821
5
1.19
0.599        0 000222
0 610
0 981            0 60
9 2906
2320
35
45.131
4 792
5
1.18
0.598
0 000222
0 607
0 985           0 60
9 2546|
570
36
46 22
4 617
5
1 16
0.592
0.000222
0 600
0 986           0 60
9 1824
10901
37
47.37
4.419
5
1 13
0.584
0 000222
0 590
0.989           0 60
9 0743
1150
38
48.13
4.303
5
1.11
0 549
0 000222
0 584
0.941             060
9 0022!
760
39a
50 94
O
39b
51 52
3 149
35
1 07
0 576
0 00025
0 570
1.010
0 60
7 3579
3390
40
53.96
2.778
3.5
10
0 556
0 00025
0 546
1.018
0 60
7 10561
2440
41
54 38
35
0.99
0 554
0 00025
0 542
1 021
0 60
7 0695
420
42
54 73
2 741
2 664
3.5
0 98
0 549
0 00025
0 539
1 019
0 50
7 0334          350
43
55 3?
2 478
3.5
0 94
0 538
0 00025
0 525
1.025           0.50
6 8892          630
44
57 82
1 982
3
0 89
0.512
0 00025
0.507
1 010          0 5Cll
6 2089       2460
45
60.18
0.899
2
0 70
0 425
0 00025
0435
0 978          0.5CJ
4 5239       2360
47
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Table 3.3: Hydraulic Particulars for Secondary Canal-RS-16. Rogosity coefficient (Manning’s n = 0.0225)
Canal side slope (1.5:1 for cut & 2:1 for fill)
May 2007
si
no
Cumulati
ve
Distance
in m
Secondary 
canal
progressrv 
e
discharge
Bed
width
(m)
Bed
level
(m)
F.SD
(m)
Velocity
(V=nVs)
Canal
bed
slope
Cntical
velocity (Vj) = O 546DoW
=m/s
V/Vo
Wetted perimete
r
Reach
length
(m)
Discharge
1
0 00
1
0 61
0412
0 00033
041
1.007
3.20
0 00
0 48
2
300
1
0 58
0403
0 00033
0 385
1 046
3.09
300
0 44
3
600
1
0 55
0 391
0 00033
0 37
1 05
2 98
300
0 395
4
900
08
0 55
0 379               0 00033
0 37
1 02
2 78
300
0 341
5
1200
06
0 55
0 364               0 00033
0 37
0 98
2 58
300
0 283
6
1500
05
0 51
0.342
0 00033
0 355
0 964
2 34
300
0.221
7
1800
0 50
0 44
0.315
000033
0 323
0 975
2.09
300
0.16
8
2100
0.5
035
0 307
0.0004
0.279
1.1
1.76
300
0 11
9
20.83
0 098
10
Table 3.4: - Hydraulic Particulars for Secondary Canal-RS-17. Rogosity coefficient (Manning's n = 0.0225)
Canal side slope (1.5:1 for cut & 2:1 for fill)
SI
no
Cumulati
ve
Distance
in km
Secondary
canal
progressrv 
e
discharge
Bed
width
(m)
Bed
level
(m)
FSD
(m)
Velocity           Canal (V=m/s) |         bed
slope
Cntical
velocity (V2) = 0 546D°“
=m/s
Wetted
perimeter
Reach
length
(m)
Discharge
V/Vo
13
0 00
058
1 00
0 67
0 433               0 00033
0 423
1.025
3 416
0 00
14
300
0 562
1 00
066
0 429               0 00033
0419
1 025
3.380
300
15
600
0 531
1.00
064
0 429               0 00033           0 410
1 045
3.308
300
16
900
0.497
1.00
062
0419                0 00033           0 402
1 042
3 235
300
17
18
1200
0461         1.00
0 60
r0.408                 0.00033
0 394
1 036
3.163
300
1500
0.42      1.00
057
0 398               0 00033
0 381
M 045
3 055
300
19
1800
0 369        0 80
0 57
0 387               0.00033
0 381
1 016
2 855
300
20       2100
0316
0 80
0.53
0 373               0 00033
0 361
1 025
2 711
300
21       2400
0 251
0 60
0 52
0 353               0 00033
0 359
0 983
2 475
300
22
2700
0 198
0 50
0 49
0.33                 0 00033
0 346
0 954
2.267
300
23
3000
0 15
0 50
043
031                  0 00033
0 318
0 974
2 050
300
24
0.114
0 50
0 36
031                  0 0004
0 284
1 09
1 798
25
33.713
26
27
28
___________
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Table 3.5: Hydraulic Particulars for Tertiary Canals Under Secondary canal -RS-16
Rogosity coefficient (Manning's n = 0.0225) Canal side slope (1.5:1 for cut & 2:1 for fi I)
Name of
Block 
(secondary 
canal)
Tertiary
canal
C.C.A
in ha
Design
capacity
m3/s
Design
capacity 
with
flexibility 
factor
(20%)
Bed
width in
m
Length
of
tertiary 
canals 
(m)
F.S.D
in (m)
Bed
Slope
Velocity
(m/s)
Vo
V/ Vo
RT-16-1
21.33
0.020
0.024
0.30
674
0.20
0 0003
0.195
0 195
1.00
RT-16-2
14.28
0.013
0.016
0.20
390
0.170
0.0003
0.177
0 176
1.00
RT-16-3
25.13       0.024
0.028
0.30
816
0.22
0.0003
0207
0207
0.985
RT-16-4
14 91       0.014
0.017          0.20
345
0.190
00003
0.18
0.189
0.954
RT-16-5
29.63       0.028
0 033          030
960
022
0.0003
0.212
1 023
RT-16-6
18 42
0.017
0.021
0.30
543
0.210
0.0003
0 195
0.207
0 201
0.97
RT-16-7
32.85
0.031
0.037
0.30
1066
0.25
0218
0 225
0.97
RS-16
RT-16-8
18 96
0.018
0 021
0.30
578
0 210
0.0003
0 0003
0 195
0.201
0.97
RT-16-9
35.71
0.034
0 040
0 30
1115
RT-16-10
19.51
0.018
0.022
0 30
578
0.26 0 210
0 0003
0.0003
0 223
0.197
0 23
0 201
0 967
0 98
RT-16-11
34.85
0.033
0.039
0.30
1114
026
0.0003
0.221
0961
RT-16-12        19.88       0.019
0.022
0 30
633
0.0003
0.197
RT-16-13        28            0.026
0.032
0.30
908
0210
0.25
00003
0.211
0.23
0.201 0213
0.98
0.99
RT-16-14        16.24       0.015
0.018
0.20
585
0.190
0.0003
0.187
0 198
0 99
RT-16-15        10 4         0.010
0.012
0.20
543
0.16
0 0003
0.164
0.168
0.97
340
10843
_____
Table 3.6: - Hydraulic Particulars for Tertiary Canals Under Secondary canal -RS-17.
Rogosity coefficient (Manning's n = 0.0225)
Canal side slope (1.5:1 for cut & 2:1 for fill)
Name of Block (seconda ry canal)
Tertiary
canal
CCA
in ha
Design
capacit
3
y m /s
Design capacity with flexibility factor (20%)
Bed
width
in m
Length
of
tertiary canals 
(™)
FSD
in (m)
Bed
Slope
Veloci
ty 
(m/s)
Vo
V/ Vo
RT-17-1
65
0 006
0.007
0.20
522
0.17
0 0003
0.167
RT-17-2
9 73
0.009
0.011
0 176
0 20
142
0 95
0 17
0.0003
0 167
RT-17-3
7 57
0.007
0 176
0.009
0 20
0 95
668
0.17
00003
RT 17-4
19.77
0 167
0.019
0 022
0 176
0.30
150
0 95
021
0 0003
RT-17-5
8.2
0.008
0.009
020
580
0 17
0.0003
RT-17-6
21.84
0.021
0.025
0.197
0.167
0 30
200
0 22
RT-17-7
11 24
0.0003
0 204
6.011
0.013
0 201
0 176
0 207
020
574
017
0 98
095 0 985
^.0003
0 167
RT 17-8
20.54
0019
0.023
0 176
030
295
0 95
0 22
RT-17-9
16.32
0015
I 0.0003
0 018
0 30
594
0.19
RT-17-10
0 0003
0 20
0 187
0 207
0 189
20
0019
0.023
030
513
0 22
RT-17-11
25 94
0.024
0 029
0.0003
0 20
0 30
0 207
523
0 966
0 99 0 966
RS-17
0 24
RT-17-12
19.89
0019
0 0003
0.022
L  0 211
0 30
768
0 219
021
RT-17-13
27.45
0.026
0 031
00003
_
0 197
0 96
0 30
666
0 201
0 27
"0 98”
RT-17-14
19.64
0.018
00003
0 022
0 216
030
1044
0 236
021
RT-17-15
37.44
0.035
0.0003
0.042
0 197
0.30
682
0 201
029
0915
0 98
RT-17-16
20 77
0 020
0.0003
0 023
0 30
1287
0 22
RT-17-17
25 48
0.024
0.029
""0.0003
0 30
674
0 233 0 20
0 247
0 207
0 24
0  942  \ 0 966
0 0003
RT-17-18
21 54
0.020
0.024
0211
0 30
868
0219
0 22
RT-17-19
21.15
0 020
0.024
00003
0.30
664
0 202
0 207
0 22
RT-17-20
21.63
0.020
0.024
030
739
0 22
RT-17-21
14
0013
0.016
0 0003
r 0.0003
0 30
0 202
0.202
656
0 207
0 207
0 21
0 96
0 97
0.97
0 97
RT-17-22
18 11
0.017
0 020
0 0003
0 30
574
0.195
0 201
0 22
0 97
0.0003
0 192
0 207
_______
415
13383
i 0 97
—
—
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4 CANAL STRUCTURES 4.1   General
May 2007
Different types  of canal structures  have been provided on the different components  of
the canal system. They include the following categories of structures
i)
ii)
Intake structures for Primary canals in the dam Control structures:-
a.   Head regulators on Primary Canals
b.   Cross regulators on Primary Canals
c.   Escape regulators on primary /Secondary Canals
iii)
Cross Drainage works:
a.   Aqueduct
b.   Syphon Aqueduct
c.   Aqueduct with earthen canal section
d.   Canal siphon
e.   Super passage
iv)
Bridges
a.   Road Bridges
b.   Foot Bridges for cattle crossing
4.2   Structures on Primary Canals
The structures under different categories proposed on the primary canals are discussed
below in brief
4.2.1  Intake structures
The Right Primary  canal takes  off from the intake structure provided in saddle no.2 and the Left Primary  canal takes  off from the intake structure provided near the left abutment of dam. The details  of these intake structures  are given under section 1.4.2 of this Report. The detailed design of these structures  have been provided in the report on Dam & Appurtenant works.
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4.2.2 Cross-Drainage Works
Both the Primary  Canals  - Right Primary  Canal and Left Primary  Canal - are contour canal and as  such, they  are crossing a large number of streams, where suitable cross drainage works of appropriate type have been provided. The number of such cross —
Drainage works is as given below:
No. of Cross - Drainage Works
S. No
Type of CD works
Right Primary
Canal
Left Primary 
Canal
Total
i
Aqueduct
2
4
6
ii
Syphon Aqueduct
17
16
33
iii
Canal Syphon
4
2
6
iv
Aqueduct       with       earthen       canal section
5
15
20
Total
28
37
65
The  locations  of  these  cross-drainage  works  a  long  with  other  details  are  a  vailable  in Table 4.1(a) to 4.4 (b).
4.2.3 Control Structures
Control structures  in form of head regulators, cross  regulators, escape regulators  are required for regulating/controlling the discharge in the canal system. Head regulators have been provided in the Primary  Canals  at the offtake of every  secondary  canal. Cross-regulators  have been provided in the Primary  canals  to regulate the discharge and levels. Some of the head regulators  have been combined with cross-regulators.
The numbers of these structures are as give below:
No. of structures
S. No
Type of CD works
Right Primary
Canal
Left Primary
Canal
Total
i
Cross   -   Regulator   combined   with Head Regulator
3
7
10
ii
Head Regulator
37
39
76
iii
Escape Regulator
1
1
2
Total
41
47
88
The locations  of cross-regulators  along with after details  are available at Tables  4.5 (a) & 4.5 (b) for Right Primary  canal and Left Primary  Canal respectively. The details  of Head Regulators  for secondary  canals  along with their locations  are available at Tables 4.6 (a) & 4.6 (b) for Right Primary  Canal & Left Primary  Canal respectively. The escape Regulator is  located al km 1.8 of Right Primary  canal and at km 3.25 of Left Primary Canal.
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4.2.4  Road Bridge / Foot Bridge
Road Bridges  have been provided to facilitate the movement of vehicles, pedestrian and livestock, Road bridges  have been provided at suitable location. Where ever possible the road bridge has  been combined with other structures  like cross-regulators, head regulators, escape regulators  etc. Altogether five road bridges  on Right primary  canal and six  road bridges  on Left primary  canal have been provided. Their locations  and other details  are available at Table 4.7 (a) & 4.7 (b) for Right and Left primary  canals respectively.
4.2.5   Foot Bridges
Apart from the road bridges  as  discussed above, foot bridges  have been provided on Primary  Canal to facilitate pestrain and cattle crossing. Altogether eight foot bridges  on Right Primary  canal and nine foot bridges  on Left Primary  canal have been provided. Of these three foot bridges  on Right Primary  canal are independent, two foot bridges  are combined with cross  regulators  and the rest three foot bridges  are combined with head regulators  for secondary  canals. In case of Left Primary  canal no independent foot bridge, has  been provided and seven foot bridges  have been combined with cross regulators  and remaining three foot bridges  have been combined with head regulators for secondary  canals. The details  of foot bridges  for Right and Left primary  canals  are available at Table 4.8 (a) and 4.8 (b) respectively.
4.2.6   Total number of structures
Thus 158 numbers of structures have been provided on both primary canals of these there are 68 structures on Right Primary canals and 90 structures on Left Primary canal. B road break up of these structures are as given below:
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S. No
Type of CD works
No. of Cross Right Primary 
Canal
- Drainage W< Left Primary 
Canal
>rks
Total
i
CD works
28
37
95
ii
Control structures
41
47
88
iii
Road / Foot Bridges
7
6
13
Total
76
90
166
4.3 Structures in Sample Area
Planning and design of micro-irrigation system has  been done in the sample area, which comprised the command areas  of secondary  canals  RS-16 and RS-17 under the Right Primary  canal. As  discussed in the previous  section the micro-irrigation system i.e. canal system in sample area consists of the following:
i)          Secondary canals - Rs - 16 & Rs-17
ii)         Tertiary canals - offtaking from the secondary canals RS-16 & RS-17
iii)        Quaternary canal - offtaking from Tertiary canals
Besides  the head regulators  for the secondary  canals  which have been provided on Primary  canals, and included in the list of structure on Primary  canals  vide Table 4.6 (a) & 4.6 (b), the following structures  have been provided for micro-irrigation in the sample area.
i)          Adjustable Proportionate Modular (APM) type outlet for Tertiary canals on
secondary canal
ii)
Drops in Secondary & Tertiary canals
iii)
Parshal Flume in secondary canals for measuring discharge
iv)
Duckbill weir in secondary canal for maintaining FSL and functioning as 
escape.
v)
Road/Foot bridges on secondary canals
vi)
Turn-out on tertiary canal to facilitate diversion of flow in the quaternary 
canals.
4.3.1 Outlet
An outlet is  a masonry  structure located on the government owned last canal system It is  very  important as  it acts  as  an interface between the state owned canal system and the users  of the system, farmers  who utilize the irrigation water. It acts  as  the head regulator for tertiary canal (which is equivalent to watercourse). Since the secondary
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canal is  aligned on ridge, the tertiary  canals  takeoff on both sides. There are 15 tertiary canals  under secondary  canal RS-16 and 22 tertiary  canals  under secondary  canal RS-17. Outlets  have been provided, at the head of all 37 tertiary  canals. There are several types  of outlets. However in order to improve the performance of the irrigation system and with a view to achieve equitable distribution of irrigation water, Adjustable Proportional Modular (APM) outlet has been provided.
4.3.2  Drops on Secondary Canals
The secondary  canals  (which are equivalent to minors) are aligned on ridges. However, the natural slope is  steeper than that required for secondary  canal. Therefore, drops have been provided to negotiate the difference of slope. As  per actual planning 15 no. of drops  have been provided on secondary  canal RS-16 and 17 no. of drops  on secondary  canal RS-17. The height of these drops  varies  between 0.5 to 1.5 m. As regards their type, a vertical drop or well type drop have been provided.
4.3.3  Drops on Tertiary canals
The tertiary  canals  have been aligned along the controur, and as  such there is  no requirement of drop However, in the end of its  course the tertiary  canal are aligned along slope where drops  are required to negotiate the slope. Longitudinal profile of following tertiary  canals  have been prepared and according to requirement the number
and location of drops have been finalized. The details are as follows:
S. No
Tertiary Canal
Length
No. of drops
Remarks
i
RT-17-8
1.3 km
16
li
RT-17-4
0.55 km
8
lii
RT-6
0.85 km
7
iv
RT-6
0.65 km
7
Total
3.35 km
38
4.3.4  Parshall Flume
Accurate measurement of discharge is  very  important for achieving equitable distribution of i rrigation w ater. With this end i n v iew a P arshall F lume h as b een p rovided i n t he head of every secondary canal.
4.3.5  Duckbill weir
A  duckbill  weir  has  been  prided  at  (be  end  of  every  secondary  cnala.  This  win  help  in maintaining the FSL at the sometime work as escape also
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4.3.6  Road Bridge/Foot Bridge
There is  no existing road in the sample area. Therefore no bridge has  been provided. However, in order to facilitate the movement of human being, cattle and/or food grains, suitable road bridges  or foot bridges  have been provided by  combining the same with drop structures.
4.1.1 Turn-out
With a view to facilitate the diversion of discharge from tertiary  canal to quaternary canals, turn-outs  (diversion boxes) have been provided at appropriate locations  in the tertiary canals.
Table 4.1(a): List of Aqueduct on Right Primary Canal
s.
No
Details          of Structure
Distance of structure from origin in km
Catchment area in sq.
km
Maximum flood
discharge in m /sec
3
Discharge of         canal m3/sec
1
Across Wama
River CDR-6
8.4
3542
100 year = 584
500 year = 776
7.028
2
CDR-19
32.1                    40.25
50 Year = 55.30
100 year = 62.40
3.128
Table 4.1 (b) List of Aqueduct Structures on Left Primary Canal
S. No
Details   of Structure
Distance of structure from origin in km
Catchment area in sq.
km
Maximum flood
discharge in m /sec
3
Discharge
of          canal m3/sec
1
CDL-3
4.7
29.6
50 Year = 43.0
100 year= 48.5
8.931
2
CDL-25
40.28
300
50 Year = 147.5
100 year= 166.5
5.161
3
CDL-28
44.81
61.0
50 Year = 40.8
100 year= 46.0
4.821
4
CDL-33
54.48
70.00
50 Year = 43.0
100 year = 48.5
2.664
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Table 4.2 (a): List of Syphon Aqueduct on Right Primary Canal
--------rrr—j“"                          Canal discharge in m3/sec
7.028
5.11             (.Uzo 7.028
7.028
3.26            6.658
6.658
6.658
4.78
4.043
1.45
Table 4.2 (b): List of Syphon Aqueduct on Left Primary Canal
May
s.
No
Details of
CD work
Distance
from origin
in km
Catchment
Area in sq.
km
Peak  flood discharge in m3/sec
CDR  2
2.90
0.875
4.75
2
- CDR- 3
3.95
2.65
5.62
7.028
3
CDR- 4
6.00
1.625
4
CDR- 5
7.60
5.84
10.75
5
CDR- 7
9.15
1.2
3.61
6
CDR- 8
10.40
1.4
7
CDR- 9
11.50
9.6
11.21
8
CDR-10
13.38
4.8251
8.90
9
CDR-11
3.275
5.61
6.315
10
CDR-12
17.20
19.55
3.75
9.65
5.981
11
CDR-13
22.45
57.6
74.00
12
CDR-15
26.00
10.67
9.04
13
CDR-18
29.70
13.87
18.90
3.644 |
14
CDR-21
33.45
1.38
2.321
2.99
151
CDR-24
37.00
2.4
5.24
1.51
16
CDR-25
38.21
15.4
16.90
17
CDR-26
39.90
8.0
10.76
0.994
S.
No
Details of
CD work
Distance
from origin
in km
Catchment
Area in sq.
km
Peak  flood discharge in m3/sec
Canal
discharge
in m3/sec
1
CDR- 1
0.60
1.95
5.50
8.968
2
CDR- 2
3.95
5.6
12.05 I
8.931
3
CDR- 4
5.28
1.2
4.92
8.863
4
CDR- 5
6.53
1.15
4.54
8.746
5
CDR- 6
7.99
0.55
1.85
8.701
6
CDR- 8
8.51
1.85
4.26
8.701
7
CDR- 9
9.23
0.45
1.64
8 701
8
CDR-10
12.36
9.65
16.56
8.455
9
CDR-13
20.65
4.3
6.19
8.198
10
CDR-17
27.93
0.94
1.98
7 334
11
CDR-18
28.84
0.90
1.49
7.292
.
13
12
CDR-21
38.25
0.5
1.85
5.286
CDR-22
38.59
0.48
1.78
5.265
14
CDR-26
40.84
1.23
2.78
5.161
15
CDR-32
54.13
7.05
10.20
2.741
16
CDR-35
56.78
2.65
5.33
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Table 4.3 (a): List of Cross Drainage Works, with canal in earthen section on
Right Primary Canal
May 2007
s.
No
Detail of CD
Work
Distance of
Structure from
origin in km
Catchment
area in sq.
km
Peak flood
discharge in
m3/sec
Discharge
of canal in
m3/sec
1
CDR- 14
24.65
10.13
25 year = 8.51
4.249
2
CDR- 16
26.5
2.2
25 year = 3.40
4.043
3
CDR -17
27.65
27.15
50 year = 35.5 / year = 40.1
3.863
4
CDR - 20
33.0
0.8
25 year = 1.45
2.99
5
CDR - 22
34.4
7.53
25 year = 9.02
2.044
Table 4.3 (b): List of Cross Drainage Works, with canal in earthen section Left
Primary Cana[
S. No
Detail of CD
Work
Distance of
Structure
from origin
in km
Catchment
area in sq.
km
Peak flood
discharge in
m3/sec
Discharge
of canal in
m3/sec
1
CDL-7
8.14
1.85
25 year = 4.26
8.701
2
CDL-11
15.35
3.75
25 year = 6.12
8.32
3
CDL-12
20.09
1.7
25 year = 3.37
8.275
4
CDL-14
24.40
11.5
25 year = 15.22
7.587
5
CDL-15
25.54
1.8
25 year = 3.58
7.587
6
CDL-16
25.88
1.45
25 year = 3.18
7 587
7         CDL-19
34.10
7.0
25 year = 8.16
8
CDL-20
6.261
36.66
0.53
25 year = 1.46
9
CDL-23
38.73
5.322
0.6
25 year = 0.99
10
CDL-24
39.48
2.54
5.265
25 year = 3.65
11
CDL-27
41.84
5.231
1.48
25 year = 3.02
12
CDL-29
48.53
5.161
3.98
25 year = 6.42
13
Tdl-so
50.01
1.43
25 year = 2.38
14
CDL-36
58.48
8.7
.
4 303
4 303
25 year = 13.40
15
CDL-37
59.00
2.3
.
1 961
25 year = 4.07
.
1.961
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Table 4.4 (a): List of Canal Syphon Structures on Right Primary Cana^
May 2007
s.
No
Location
Distance
from origin
km
Catchment
area is sq.
km
Peak flood discharge
in m3/sec
Canal
discharge
in m3/sec
1
CDR-1
2.00 km
2.50
25 Year= 10.0
7.028
2
CDR-23
36.50 km
1.05
25 Year = 2.20
1.51
3
CDR-27
41.4
3.3
25 Year = 5.39
0.735
4
CDR-28
42.4
33
50 year = 39.10
100 year= 44.10
0.624
____________
Table 4.4 (b): List of Canal Syphon Structures on Left Primary Canal
1
CDL-31
52.52
2.1
25 year = 3.17
2.778
2
CDL-34
55.04
2.45
25 year = 5.10
2478
s.
No
Table 4.5 (a): List of Proposed head and cross Regulators /Escape on Right
Primary canal
Name of structure
Distance
from head
of canal in
km
Discharge of primary 
canal in m3/sec 
Upstream = u / s
Dwonstream = d! s
Discharge of
secondary canal
in m3/sec
Remark
1
20.95
u/s = 5.523
d/s = 4.969
0.58
Designed
2
Q
30.8
u/s = 3.52
d/s = 3.234
0.30
0
H.   Regulator   for   secondary canal     RS-17     and     cross regulator and foot Bridge No. 5 H.   Regulator   for   secondary canal  RS-17,  cross  regulator with  Road  Bridge  No.  4  for Access Road
H.   Regulator   for   secondary canal  RS-28,  cross  regulator and foot Bridge No. 8
40.65
ui s 0.994
<7/s0.735
0 272
4
Escape  with  cross  regulator and Foot Bridge
1.80
u/s = 7.028
d/s = 7.028
Escape
—----------- —
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Table 4.5 (b): List of Proposed head and cross Regulators /Escape on Left
1
H. Regulator for secondary  canal DL-9, cross  regulator and Foot Bridge (Cattle crossing)
10.51
u/s 8.61
0.162
d/s 8.455
2
H. Regulator for secondary  canal DL-15, crossing Regulator Foot Bridge No. 3 (Cattle crossing)
23.15
u/s 8.062
d/s 7.663
0.417
3
H.   Regulator   for   secondary   canal   DL-23, cross Regulator and Foot Bridge No. 4
32.16
u/s 7.058
d/s 6.378
0.711
4
H.   Regulator   for   secondary   canal   DL-26, cross regulator, Foot Bridge 5
36.05
u/s 6.164
d/s 5.332
0.881
5
H.  Regulator  for  Secondary  canal  DL  -  33 crossing Regulator with Foot Bridge No. 6
42.24
u/s 5.013
rf/s 4.897
0.12
6
H  Regulator  for  secondary  canal  DL  -  39. cross Regulator, Foot Bridge No. 7
r 50.94
u/s 4.303
d/s 3.149
1.206
7
H.   Regulator   for   secondary   canal   DL-44, cross regulator Foot Bridge No. 8
55.36
u/s 2.478
d/s 1.982
0.519
8
Escape with cross regulator and foot Bridge
3.25
8 931
8.00
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Table 4.6 (a): List Of Head Regulator on Right Primary Canal
5
*         Name of structure
No.
1 Head Regulator for Secondary canal RS-1
2 Head Regulator for Secondary canal RS-2
3 Head Regulator for Secondary canal RS-3
4 Head Regulator for Secondary canal RS-4
5 Head Regulator for Secondary canal RS-5
6 Head Regulator for Secondary canal RS-6
7 Head Regulator for Secondary canal RS-7
8 Head Regulator for Secondary canal RS-8
9 Head Regulator for Secondary canal RS-9
10 Head Regulator for Secondary canal RS-10
11 Head Regulator for Secondary canal RS-11
12 Head Regulator for Secondary canal RS-12
13 Head Regulator for Secondary canal RS-13
14 Head Regulator for Secondary canal RS-14
15 Head Regulator for Secondary canal RS-15
16 Head Regulator for Secondary canal RS-16
17 Head Regulator for Secondary canal RS-18
Distance             Discharge of
from origin in
KM
0.555
1.692
2.951
4.142
4.887
5.750
6.123
10.14
10.97
12.382
15.010 16.393
17.186
17.756
18.884
21.327
22.762
Primary canal in
m3/sec in m3/sec
u/s=7.521 d/s=7.464
u/s=7.464 d/s=7.358
u/s=7.358 d/s=7.298
u/s=7.298 d/s=7.228
u/s=7.228 d/s=7.127
u/s=7.127 d/s=7.087
u/s=7.087
d/s=7.030
u/s=7.030
d/s=6.973
u/s=6.973
d/s=6.925
u/s=6.925 d/s=6.803
u/s=6.803 d/s=6.576
u/s=6 576 d/s=6.447
u/s=6.447 d/s=6.315
u/s=6.315
d/s=6.207
u/s=6.207
d/s=5.981
u/s=5.981
d/s=5.523 u/s=4.969
d/s=4.78
May 2007
Discharge of
Secondary canal in Remarks
m3/sec
0.0.057
0.106
0.06
0.07
0.101
0.04
0.057
0.077
0.028
0.122 0.086
0.135 0.132
0.120
0.237
0.478
0.198
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18I Head Regulator for
23.797
Secondary canal RS-19
u/s=4.78
d/s=4.524
19' Head Regulator for
24.842
Secondary canal RS-20
u/s=4.524
d/s=4.249
20    Head Regulator for
26.347
u/s=4.249
Secondary canal-DR-21
d/s=4.043
21    Head Regulator for
28.063
u/s=4.043
Secondary canal- RS -22
d/s=3.863
and foot bridge no. 6
22    Head Regulator for
28.868
Secondary canal- RS -23
u/s=3.863
d/s=3.77
23    Head Regulator for
29.761
u/s=3.77
Secondary canal- RS -24
d/s=3.683
24   Head Regulator for
30.285
u/s=3 683
Secondary canal- RS -25
d/s=3.664
25   Head Regulator for
31.332
Secondary canal- RS -26
u/s=3.664
d/s=3.52
26   Head Regulator for
32.96
u/s=3.234
Secondary canal- RS -28
d/s=3 188
27   Head Regulator for
33.818
Secondary canal- RS -29
u/s=3.188
d/s=2.99
28   Head Regulator for
34.819
u/s=2.99
0.266
0.288
0.216
0.187
0.098
0.090
0.040
0.130
0.048
0.207
0.690
Secondary canal- RS -30
d/s=2.33
29   Head Regulator for
34.218
u/s=2.33
d/s=2.044
0 296
Secondary canal- RS -31
and foot bridge no.7
30    Head Regulator for
35.922
u/s=2.044
Secondary canal RS-32
d/s= 1.802
31    Head Regulator for
36.475
u/s= 1.802
Secondary canal RS-33
d/s= 1.649
32    Head Regulator for
37.418
u/s= 1.649
Secondary canal RS-34
d/s=1.51
33    Head Regulator for
38.537
Secondary canal RS-35
u/s=1.51
d/s=1.41
34    Head Regulator for
39.556
u/s=1.41
Secondary canal RS-36
d/s=1.199
35    Head Regulator for
40.207
u/s= 1.199
Secondary canal RS-37
d/s=0.994
36    Head Regulator for
43.109
Secondary canal RS-39
u/s=0.735
d/s=0.624
37    Head Regulator for
44.166
Secondary canal RS-40
u/s=0.624
d/s=0.563
0.253
0.160
0.145
0.104
0.220
0.214
0.116
0.063
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Table 4.6 (b): List of Head Regulator on Left Primary Canal
S.No. Name of structure Distance
from origin
Discharge of
Primary canal
Discharge of Secondary canal
0.048
0.039
0.047
0.029
0.042
0.075
Remarks
1
Head Regulator for
0.157
Secondary canal-LS-1
u/s=9.015
d/s=8.968
2
Head Regulator for
3.126
Secondary canal- LS -2
u/s=8.968
d/s=8.931
3
Head Regulator for
3.749
Secondary canal- LS -3
u/s=8.931
d/s=8.886
4
Head Regulator for
4.638
Secondary canal-DL-4
u/s=8.886
d/s=8.863
5
Head Regulator for
5.411
u/s=8.863
Secondary canal-DL-5
d/s=8.818
6
Head Regulator for
6.084
u/s=8.818
Secondary canal- LS -6
d/s=8.746
and foot bridge no1
7
Head Regulator for
6.553
Secondary canal- LS -7
u/s=8.746
d/s=8.701
8
Head Regulator for
9.89
u/s=8.701
Secondary canal- LS -8
d/s=8.61
9
Head Regulator for
13.994
Secondary canal- LS -10
u/s=8.455
d/s=8.32
10
Head Regulator for
15.906
u/s=8.32
d/s=8.275
0.047
0.095
0.141
0.047
Secondary canal- LS -11
and foot bridge no.2
11
Head Regulator for
20.16
u/s=8.275
Secondary canal- LS -12
d/s=8.198
12
Head Regulator for
20.718
Secondary canal- LS -13
u/s=8.198
d/s=8.12
13
Head Regulator for
21.693
Secondary canal- LS -14
u/s=8.12
d/s=8.062
14
Head Regulator for
23.617
u/s=7.663
Secondary canal- LS -16
d/s=7.587
15
Head Regulator for
26.86
u/s=7.587
Secondary canal- LS -17
0.081
0.081 0.061
0 08 0.181
d/s=7.413
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16      Head Regulator for
27.653
u/s=7.413
0.083
Secondary canal- LS -18
d/s=7 334
17      Head Regulator for
28.869
u/s=7.334
0.044
Secondary canal- LS -19
d/s=7.292
18      Head Regulator for
29.526
u/s=7.292
d/s=7.267
0.027
Secondary canal- LS -20
19      Head Regulator for
30.333
u/s=7.267
0.05
Secondary canal- LS -21
d/s= 7.219
20      Head Regulator for
31.096
u/s=7.219
d/s=7.058
0.169
Secondary canal- LS -22
21      Head Regulator for
33 955
u/s=6.378
0.121
Secondary canal- LS -24
d/s=6.262
22      Head Regulator for
35.266
u/s=6.262
0.103
Secondary canal- LS -25
d/s=6.164
23      Head Regulator for
36.718
u/s=5.322
d/s=5.286
0.038
Secondary canal- LS -27
24      Head Regulator for
38.076
0.022
Secondary canal- LS -28
u/s=5.286
d/s=5.265
25      Head Regulator for
38.912
u/s=5.265
d/s=5.231
0.036
Secondary canal- LS -29
26      Head Regulator for
39.737
Secondary canal- LS -30
u/s=5.231
d/s=5.161
0.073
27      Head Regulator for
40.137
Secondary canal- LS -31
u/s=5.161
d/s=5.125
0.038
28      Head Regulator for
40.818
u/s=5.125
Secondary canal- LS -32
0.118
d/s=5.013
29      Head Regulator for
44.312
Secondary canal- LS -34
u/s=4.897
d/s=4.821
0.08
30      Head Regulator for
45.008
Secondary canal- LS -35
u/s=4.821
0.033
d/s=4.792
31      Head Regulator for
46.236
Secondary canal- LS -36
u/s=4 792
d/s=4 617
0.18
32      Head Regulator for
47.563
Secondary canal- LS -37
u/s=4.617
0.207
d/s=4.419
33      Head Regulator for
48 203
u/s=4.419
0.12
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]
]
]
]
1
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1
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Irrigation & Drainage
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Secondary canal LS -38
d/s=4.303
34
Head Regulator for
54.124
Secondary canal- LS -40
u/s=3.149
d/s=2.778
35
Head Regulator for
54.483
Secondary canal- LS -41
u/s=2.778
d/s=2.741
36
Head Regulator for
54.688
Secondary canal- LS -42
u/s=2.741
d/s=2.664
37
Head Regulator for
55.382
u/s= 2.664
Secondary canal- LS -43
d/s=2.478
39 He
ad Regulator for
60.18
u/s=1.982
d/s=0.915
0.388
0.037
0.081
0.194
1.067
Secondary canal- LS -45
and end structure
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Table 4.7 (a): List of Road Bridges on Right Primary Canal
May 2007
S. No
Details of Bridge
Distance from origin in km
Discharge of canal in m3/sec
Bed  width in m
Depth of water in
m
Width     of canal at
FSL
1
Road Bridge No.1 for Access Road
5.50
7.028
6.25
1.35
10.30
2
Road  Bridge  for  Katketo  Hol spring to Wama-Adere
15.00
6.576
6.00
1.33
10.00
3
Road Bridge No. 3 for Access Road
24.50
4.249
4.5
1.16
7.88
4
Road Bridge No. 4 for access road combined with head Regulator for DR-17 and cross regulator
30.8
3.234
3.5
1.08
6.74
I5
Road Bridge No. 5 for Access
Road
35.75
1.649
2
0.96
4.88
—
1
11.00
8.455
7.5
1.36
11.58
2
18.50
Table 4.7 (b): List of Road Bridges on Left Primary Canal
Road  Bridge  No.1  for Access Road
Road  Bridge  No.2  for Access Road
Road  Bridge  No.3  for Access Road
Road Bridge No.4 for Access Road
Road  Bridge  No.5  for Access Road
8.275
7.5
1.35
11.55
3
41.50
5.013
5
1.21
8.65
4
46.50
4.617
5
1.16
8.50
5
53.00
2 778
3.5
1.0
6.50
b
Road Bridge No.6 for Access Road
59.50
1.961
3.0
0.89
5.70
Table 4.8(a): List of Foot Bridges (Cattle Crossings) on Right Primary Canal D Independent -foot Bridges (cattle crossinost
S. No   DDeetatial il
Distance T
from origin
1
2
3
--------------------- -------- -------- in km
Foot Bridge No.1
2.5
Canal
discharge
in m3/sec
7.028
Bed
width m
Depth of
water in
m
Width of
canal FSL
Foot bridge No. 3
Foot Bridge No. 4
6.25
12.00
19.00
1.35
6.b58
~10.30
6.00
1.33
5.981
6.00
1.26
10.00"
978
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00 t
s.
No
-ooi oriage comDineo wun ouiei Detail
JUIUI co
Distance from
origin in km
Canal
discharge in
m3/sec
Bed width m
1
Head regulator for DR 0-2 and
cross regulator foot bridge No.2
9.30
D/s 6.658
6.00
2
Head regulator for DR-7 cross regulator A foot bridge No.5
20.95
D/S 4.969
5.00
3
Head regulator for DR-12 and Foot Bridge No 6
27.65
D/s 3.863
4.00
4
Head regulator for DR-21 and Foot Bridge No. 7
34.1
D/s 2.044
2.5
5
Head Regulator for DR-28, cross Regulator and Foot Bridge No. 8
40.65
D/s 0.735
1.3
1
Table 4.8 (b): List of Foot Bridges Provided in Left Primary Canal
Head regulator for DL-6 and Foot Bridge No.1
Head regulator for DL-9 Cross regulator and
Foot Bridge
Head regulator for DL-11 and Foot Bridge No. 2
Head  regulator  for  DL-15, cross regulator & Foot
Bridge No. 3 Head  regulator  for  DL-23, cross regulator,
Foot Bridge No. 4 Head  regulator  for  DL-26, cross regulator,
Foot Bridge No. 5 Head  Regulator  for  DI-33, cross Regulator,
Foot bridge No. 6 Head Regulator for DL-39, cross regulator and
Foot Bridge No. 7
6.00
D/s 8.818
7.5
2
1.40
11.70
10.51
D/s 8.455
7.5
1.36
11.60
3
15.76
D/s 8.275
4
7.5
1.35
11 55
23.15
D/s 7.663
5
7.0
1 34
.
11 nn
I I .uu
32.16
6
D/s 6.378
6.00
1 27
.
y.ou
Q on
36.05
7
D/s 5.322
5
1 25
.
o. r
Q 7C
42.24
8
D/s 4.897
5
1 20
50.94
9
Head Regulator for DL - 44 cross regulator and
Foot bridge No. 8
D/s 3.149
35
o.bO
6.70
55.36
D/s 1 982
.
3
“ ------------
i .Ur
0.89
5.70
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5 LONGITUDINAL PROFILES AND CROSS- SECTIONS
5.1  Longitudinal profiles
The longitudinal profiles of the following components of the canal system have been
prepared
i)           Primary Canals
-  Right Primary Canal
-  Left Primary Canal
ii)  Secondary Canal
- Secondary canal No RS - 16
Secondary Canal No. RS - 17
iii)   Tertiary Canals
Tertiary Canal No. RT - 16-1
Tertiary Canal No. RT - 16-3
Tertiary Canal No RT - 17-8
Tertiary Canal No. RT - 17-15
iv) Quaternary Canals
Quaternary Canal No. RQ-16-1-1
Quaternary Canal No. RQ-17-8-1
Quaternary Canal No. RQ-17-15-1
5.1.1 Longitudinal Profiles of Primary Canals
The longitudinal profiles  of Primary  Canals  - Right & Left - show the natural ground level, canal bed level, full supply  level and the top of bank  level. It also shows  the offtake of secondary canals and the location of Cross - Drainage works.
These  are  available  at  drawing  No.  AD-F-C-RP-1  to  7  and  AD-F-C-LP-1  to  9  These longitudinal profiles have formed the basis for calculation of earthwork
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5.1.2  Longitudinal Profiles of Secondary Canals.
The longitudinal profiles of two secondary canal vide RS-16 & RS-17 located in sample area have been prepared. They  show the location of structures  and offtake points  of tertiary canals. These longitudinal profiles are available at drawing no. AD-C-RS-16-1 & AD-C-RS-17-1. The quantities  earth work  have been calculated on the basis  of these longitudinal profiles.
5.1.3  Longitudinal Profile of Tertiary Canals
The longitudinal profiles of four tertiary canals (RT16-1, 16-3, 17-8 & 17-15) have been prepared: They  are available at drawing no. AD-F-C-RT-16-1/1, RT-16-3/1, RT-17-8/. RT-17-15/1 The quantity of earth work in these tertiary canals have been estimated on the basis of these longitudinal profiles.
5.2   Cross - Section of Canal
The cross-sections of following components of canal have been prepared:
i)           Typical cross section for Primary canal in
-  Completely filling
-  Partially cutting and partially filling
-  Completely cutting (deep cutting)
ii) Typical section for secondary canals
iii)  Typical section for Tertiary canal
5.2.1 Typical cross-section for Primary Canal
The important parameters for cross-section of the Primary Canal have been adopted as follows:
i) Side Slope
Considering the type of soil, which is predominantly clay, the side slope of canals filling reaches has been adopted as 2:1 (2 horizontal and 1 vertical) and in cutting reach as 11/2:1 (11/2 horizontal to 1 vertical).
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5.1.2  Longitudinal Profiles of Secondary Canals.
The longitudinal profiles of two secondary canal vide RS-16 & RS-17 located in sample area have been prepared They show the location of structures and offtake points of tertiary canals. These longitudinal profiles are available at drawing no. AD-C-RS-16-1 & AD-C-RS-17-1. The quantities earth work have been calculated on the basis of these longitudinal profiles.
5.1.3  Longitudinal Profile of Tertiary Canals
The longitudinal profiles of four tertiary canals (RT16-1, 16-3, 17-8 & 17-15) have been prepared: They  are available at drawing no. AD-F-C-RT-16-1/1, RT-16-3/1, RT-17-8/, RT-17-15/1. The quantity of earth work in these tertiary canals have been estimated on the basis of these longitudinal profiles.
5.2   Cross - Section of Canal
The cross-sections of following components of canal have been prepared:
i) Typical cross section for Primary canal in
-  Completely filling
-  Partially cutting and partially filling
-  Completely cutting (deep cutting)
li) Typical section for secondary canals
iii) Typical section for Tertiary canal
5.2.1 Typical cross-section for Primary Canal
The important parameters for cross-section of the Primary Canal have been adopted as follows:
i) Side Slope
Considering the type of soil, which is  predominantly  clay, the side slope of canals  in filling reaches has been adopted as 2:1 (2 horizontal and 1 vertical) and in cutting reach as 11/2:1 (11/2 horizontal to 1 vertical)
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3
ii)  Free board
Taking into consideration the discharging capacity of canal which varies from 7.521 to 0.546 m /s for Right Primary Canal & from 9.015 to 0.719 m /sec for Left Primary Canal, the free board of 0.7 m has been provided in the head reach, which has reduced to 0.50 m in the tail end.
iii)  Top width of to Bank
The top width of the banks has been kept in accordance with the design criteria already furnished under Final Interim Report. According the top of service road side of Primary canals  has  been kept as  5.0 m and that for the non-service road, as  2.5 m. Similar arrangement has  been made for secondary  canals. In case of tertiary  canals  the top width of both the banks has been kept as 2.5 m.
iv)  Berm width
The following criteria have been adopted
•     In partially cutting and filling reach berm has been kept at full supply level equal to 2D, where D is full supply depth
•     In complete filling reach the berm has been kept at full supply Ievel equal to 3D, where D is the full supply depth
•     In complete cutting reach, berm has been provided at full supply level equal to 2D. where D is fall supply depth.
5.2.2  Typical Cross-Section for Secondary Canal
A  typical  cross  section  for  Secondary  Canal  has  been  prepared  and  is  available  at drawing No. AD-F-C-RS-10
5.2.3  Typical Cross - Section for Tertiary Canal
A typical cross-section for tertiary canal is available at relevant drawing for longitudinal profit. It is  to be noted that while Primary  and Secondary  canals  have been provided with a telescopic  section (section getting reduced from head to tail with discharge getting reduced) the section of tertiary canal (which is equivalent to water course) has been kept constant from head to tail. This has been done to facilitate diversion of entire discharge in one quaternary  canal at one time. This  will help to achieve equitable distribution of irrigations water and improve the quality of service of irrigation
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5.2.4 Typical Cross-Section for Quaternary Canals
May 2007
The typical sections of quaternary canal is available in relevant Drawing for longitudinal profit. This is to be noted that the section of quaternary canals has been kept the same as the parent tertiary canal. This has been provided to facilitate the diversion of entire discharge of tertiary canal to an individual tertiary canal, as it is i ntended to o perate quaternary canals turn-by-tern with full discharge of tertiary canal in one quaternary canal at a time only for short duration.
5.3 Service Road
The inspection path (also called service road) has been provided on one of the canal banks in Primary Canals. Since both the Primary canals - Right & Left - are contour canal, the inspection path has been provided on left bank in case of Right Primary Canal and on right bank in case of Left Primary Canal so that it is facing the command area and facilitates  the entry  into command area through the service road , along the secondary canals. The width of service road has been kept as 5.0 meters. The service road has been provided on the top of the bank in case of Primary Canal and Secondary canals. S ervice r oad has a Iso b een p rovided a long t ertiary canal on n atural surface level and it is located between the tertiary drain and tertiary canal. However, service road has  not been provided along quaternary  canal. Service road provided along Primary, Secondary  and tertiary  canals  will facilitate inspection of the work  and operation maintenance of the system as well as access to the fields for taking in the inputs and taking out the produce from the fields.
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6. HYDRAULIC DESIGN OF CANAL STRUCUTERS
May 2007
6.1  General
Detailed hydraulic design of the canal structures has been done for different types of structures on Primary canals and on distribution system in sample area. Attempt has been made to prepare at least one sample design of each type of canal structures under different categories. These included the following categories of structures.
v)       Intake structures for Primary canals in the dam
vi)      Control structures:-
a.  Head regulators on Primary Canals
b.  Cross regulators on Primary Canals
c.  Escape regulators on primary /Secondary Canals
vii)      Cross Drainage works:
a.  Aqueduct
b.  Syphon Aqueduct
c.  Aqueduct with earthen canal section
d.  Canal siphon
e.  Super passage
viii)     Bridges
a Road Bridges
b Foot Bridges for cattle crossing
6.2  Structures on Primary Canals
6.2.1 Intake structures
The detailed hydraulic design of intake structures for both the Primary canals has been done and these have included in the Report on Dam and Appurtenant works
6.3  Control Structures
i)
ii)
iii)
Head Regulator for Secondary Canal RS-16
Head Regulator for Secondary Canal RS-17
Escape Regulator at 1.8 km of Right Primary Canal
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6.4  Cross Drainage Works
The detailed hydraulic of the following cross-drainage works have been done:
i)
ii)
Aqueduct on river Warna at km 8.0 of Right Primary Canal Syphon aqueduct at km 22.0 of Right Primary Canal
iii)
Canal Syphon at km 2.0 of Right Primary Canal
iv)
Aqueduct (with normal canal section) at km 25.54 of Left Primary Canal
6.5  Road / Foot Bridge
The detailed hydraulic  design of two road bridge one on Right Primary  canal and another on Left Primary  Canal has  been done. Detailed design of one foot bridge on Right Primary  Canal has  also been done. The locations  of these road /foot bridges  are as given below:
i)
ii)
Road bridge at km. 15.0 of Right Primary Canal
Road bridge at km. 41.15 of Left Primary Canal
iii)
Foot bridge at km 19.0 of Right Primary Canal
6.6   Structures on Distribution Network
Besides   the   structures   on   Primary   Canals,   the   hydraulic   design   of   following   canal structures has also been done for distribution network of canal system
i)         Adjustable Proportionate Modular (APM) Outlet
ii)         Duck bill weir
iii)       Turn-out
iv)        1.5 Vertical Fall on Secondary Canal
v)        1.0 Vertical Fall on Tertiary Canal
vi)        Parshall Flume on Secondary Canal
6.7  Design Calculations
The  design  calculations  for  the  hydraulic  design  of  these  canal  structures  are  available in a separate annexure as, Annexure -11- Part I - Design Report.
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6.8   Detailed Drawings
Based on the calculation of hydraulic  design of this structure, detailed drawings have been prepared for a II t hese structures. Thus the detailed drawings for sixteen canal structures, ten number of structures on Primary Canals and six number of structures on distribution network in sample area, have been prepared. These drawings are available in separate volume as Annexure - 11 Part II Drawings.
6.9   Estimate
The detailed drawings have been used for the estimation of quantities for different items of work. The detailed estimates  for the canal structures  for the Project is  based on these sample estimate.
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7 PLANNING AND DESIGN OF DRAINAGE SYSTEM 7.1 Introduction
May 2007
Drainage is considered an integral part of the irrigation system. Lack of proper drainage system or inadequate and deficient drainage system may  result into very  serious adverse consequences. In this background, the drainage system in the command of project has been studied. The preliminary study indicates that there is no apprehension of rise of ground water and hence sub-surface drainage has not bean considered. However due care has been taken to plan and design the surface drainage system both at micro and macro levels.
7.2  Impact Irrigation on Existing Ground Water
In order to examine the need or otherwise the provision of sub-surface drainage system, the impact of irrigation on the rise of ground water has been studied and this is 
discussed hereunder in brief.
7.2.1  Existing Natural Drainage System
River Dedessa divides the command area into two parts as it flows through command and it acts as the main drainage system for the command area. Besides, there are a large number of natural drainage channels flowing across the command area on both banks  of River Dedessa. These channels  are very  useful for the drainage of the command area and they will continue to play important role in draining the surface run off due to rain and excess irrigation water during post project period. The bed and water levels in River Dedessa are also very low and the water level will remain considerably lower during the operation of the project due to construction of dam, which will facilitate drainage of command area.
7.2.2  Existing Ground Water Level
The ground water in the proposed command area is very deep. During rainy season the average ground water table was found 2 meter below surface except in few exceptional cases of surface water logging. During dry season the ground water table was found more than 5 meters below natural surface Thus the present situation of ground water table prevailing in the back ground of good rainfall indicates that there may not any apprehension of considerable rise of ground water table during post project period
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7.2.3 Ground Water Recharge from irrigation
May 2007
Cultivation of paddy  has  been proposed along with several other crops. Paddy  is  the only  crop, which requires  constant standing water in the field for its  growth and development. This  results  into percolation loss, and only  that quantity  of water which is lost through percolation has  the chance and tendency  of reaching ground water. It may be noted that about 330 mm of water is  estimated to be lost through percolation, and only  this  quantity  of water has  the scope of reaching ground water, which may  add to the rise of ground water. The intensity  of paddy  is  only  30% in Phase-I, which will increase finally  to 45% in Phase - II. Considering the entire command on an average, the annual contributions  of irrigation water to the ground water would be 99 mm in the Phase I, which will increase to 148.5 mm under Phase-ll. These additions  to ground water is also not very significant.
As  regards  other crops, they  are all dry  irrigated i.e., no standing water is  required. The irrigation water applied to the field in case of all other crops  except paddy  will be contained as  soil moisture within the root zone. Very  small amount of water, which will be lost below the root zone, will reach the ground water. Other losses  will be in form of surface run-off, which will be taken care by  surface drainage system. As  such the addition to ground water due to irrigation of all other crops  except paddy  may  be considered very negligible and therefore, may be neglected.
7.2.4  Ground Water Recharge from Seepage from Canal System
There will be seepage losses  and other losses  from the major canal components  like primary  and secondary  canals. The seepage losses  from Primary  & Secondary  Canals will be more as  they  will run continuously  for major part of the year. The ground water recharge due to seepage loss  from Primary, Secondary  & Tertiary  canals  has  been estimated and it has  been found the ground water recharge due to seepage losses  from the canal system will amount to 269.7 mm. This  ground water recharge along with the ground water recharge from the irrigation water amounting to 148.5 mm total being
418.2 mm, may lead to annual rise in ground water of 224mm This ;<=
iin» is not significant
and does not call for sub-surface drainage
7.2.5 Surface Water Logging
Surface water logging in form of swamps have been observed i
In the command area
This phenomenon is found due to topographic feature I ike - flat land with d
----- 1 epressed
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elevation. The vertisols in most parts have encountered pounds or sinkhobs w
diameter ranging from 1.0 and 1.5 meters. If proper surface drainage system is 
provided, this phenomenon will be taken care of.
7.3    Need for Surface Drainage System
It i s proposed t o provide d etailed surface d rainage system a s a n i ntegral part o f t he irrigation system both at macro and micro levels. In view of the above discussion, it transpires  that there is  no apprehension of rise of ground water necessitating sub surface drainage. However, it suggests the need and necessity for providing elaborate surface drainage system. Therefore, the surface drainage system for the project should be planned, designed constructed and maintained properly so that it functions efficiently and effectively. In this way, if proper surface drainage system is implemented and its proper functioning is  ensured, there will be no appreciable rise in ground water necessitating implementation of sub-surface drainage system. W ith this  end in view detailed planning and design of drainage system has been done.
7.4  Nomenclature & Numbering of Drainage System
The nomenclature and numbering of the drainage system have been developed on the same pattern as for canal system. One drainage channel has been provided between two quaternary canals and this drainage channel has been named as quaternary drain (QD). The quaternary  drains  finally  join the tertiary  drain. Similarly  one tertiary  drain has  been provided for the command of one tertiary  canal. It may  be noted that the tertiary canals are aligned along the contour, therefore one tertiary drain can not serve two tertiary canals. The tertiary drains join the secondary drains - either natural existing or proposed one. The tertiary drains are joining the secondary dram from both sides
On the pattern of canal system the drainage system has a Iso been numbered The quaternary drains have been numbered as RQD-1-1-1, the prefix letter R or L stands for Right & Left Primary command. The first digit stands for the number of secondary drain the second digit for the number of tertiary drain under the command of secondary canal and the t hird digit f or t he n umber of quaternary d ram. Similarly T ertiary drains have been numbered as RTD-1-1, or LTD-1-1. The secondary drains have been numbered as RSD-1,2... & LSD-1.2
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7.5 Macro-Drainage System
May 2007
River Dedessa divides  the command into two parts  and acts  as  master drainage channel. There are a large number natural streams passing through command area on both banks and joining the river Dedessa. There are 25 number of natural streams on right bank and 42 number on the left, bank. Dictated by the topographical features 40 secondary  canals  have been provided on the right bank. In general one secondary canal has been provided for the area between two adjoining natural drainage stream. However, there are several situations where two secondary canals have been provided between two natural drainage channel as there are two distinct ridges with a marked valley  without any  existing natural drainage channel. In such situation a secondary 
drain  has  been  provided  between  the  two  secondary  canals.  Thus  there  are  39
secondary drains on the right bank out of which 25 secondary drains are natural existing ones and remaining 14 will be constructed.
Similarly there are 45 secondary canals and 45 secondary drains on the left bank. Out of these secondary drains 42 number of natural and balance - 3 number of drains are proposed for construction. The secondary drains - both naturally existing and proposed to be constructed - have been numbered serially  as  RSD-1,2,. . 49 for right bank command and as  LDS-1,235 for the left bank. The Layout and location of these drains  have been shown on map available at Fig1.5. The details  of the secondary drains along with the length of proposed drains are available at Table 6.1.
Altogether 14 secondary drains with length varying between 637 m to 2.589 km (with
total length of 20,205 km) have been proposed to be constructed on right bank. On the
left bank o nly t hree s econdary c anals with I ength v arying between 645 m t o 1 240 m (with total length of 2.693 km) have been proposed to be constructed.
7.6   Layout of Micro-drainage System in Sample Area
The sample area which has been selected for the planning and design of micro-irrigation & micro-drainage system consists of command area of two secondary canals RS-16 & RS-17 and it is bounded by two naturally existing drainage stream number RSD-14 and RSD-16.
Since there are two distinct ridges in the sample area, so two secondary canals viz
RS-16 and RS-17 have been planned and in between the two secondary canals one secondary drain RSD 15 have been provided, which has been aligned along a existin
o
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distinct valley. The Iayout of micro-drainage system has been shown along layout of micro-irrigation system in the map available at Fig 1 6
7.7    Design Criteria for Surface Drains 7.7.1   Field Drains
<)
The design and planning of field drainage system have been fully  co ordinated with the other drainage systems in the area Field drains should be aligned as far as possible along the valley lines but the alignment should be directed away  from depression and ponds. The maximum drainage Aater level in the drainage channel will be kept below the general ground level
H) Drains  of size bigger than are normally  required to carry  design discharge more frequently lend to get silted up and create conditions favorable for <veed growth As  such slightly  smaller size drains  which induce flows  on the scouring side at higher stage levels  corresponding to designed discharge should he preferred
HI)
The maximum 1 day. 2 days and 3 days rainfall occurring with different
frequency (2 to 50 yr) have been provided by the Meteorological and
Hydrological study group The drains have been designed for 1 day average
of J days maximum rainfall of 50 year return period, which is 88 mm
IV)
In  absence  of  dependable  data,  the  run  off  has  been  calculated  by  assuming
run off percentage of 0 50 for clayey soil/ puddle paddy fields
V)
The  period  of  disposal  of  rainfall  depends  upon  types  of  crops  and  stage  of
their growth The following values have been take into consideration
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Crops
Paddy and Sugarcane Bajra and Cotton Sorghum and Maize Vegetables
Period
disposal
7 days 3 days 2 days
1 day
Remarks
Panicles in the case of paddy not to get sub-merged
3 days rainfall to drained in 3 days
2 days rainfall to be drained in 2 days
24 hour rainfall to be drained in 24 hours
However, for most crops the level of protection normally planned is from a storm of 24-72 hours and with a frequency of occurrence of 2-5 years.
vi)       The cross drainage structures on field drains have been designed for a 1 day average of 3 days maximum rainfall of 15 year frequency assuming the same time of disposal of run-off as given above.
vii)       The  velocity  of  flow  in  drainage  channel  has  been  computed  by  using Manning’s formula assuming ‘n’ value of 0.0225 for earth channels free from vegetation.   The   side   slopes   should   be   1   horizontal   to   1   vertical or 1| horizontal to 1 vertical or even greater depending upon type of soil.
viii)     Field drains designed to convey excess run-off due to rainfall will usually be adequate  to  convey  excess  irrigation  water.  Where  rainfall  intensities  are low, field drains should sufficiently large to convey excess irrigation water. Shallow drains with water depth not exceeding 0.3 to 0.6 m are preferable to deep drains from the point of view of maintenance.
7.7.2 Design Details
Drainage Discharge: The following formulae has been used for calculating the rate of runoff for drainage design
Q = (in metric units)
Where, Q = Discharge A = Area
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R = Rainfall
F = Run off co-efficient. (Value of F-0.4 - 0.6)
( For peak runoff, value of F = 0.8 - 0.9)
T = Time of removal, seconds for area 500 ha = 1 day 1000 ha = 2 days
>1000 ha = 3 days
Side Slopes
In general side slopes are:
May 2007
Cut in firm soil
1:
Cut in loam
1
Cut in sandy soils 
1:
Permissible Velocities
Sandy loam
Loam
Clay
0.60 m/sec
0.75 m/sec
1.00 m/sec
3
Cross-section
The drain is designed as an open channel with uniform flow by using Manning’s formula.
V = -/d  S'l" (in metric units) and
n1           1
Q = AxV
Where, n = Rugosity co-efficient
R = Hydraulic Radius
S = Gradient
The value of 'o' in the above formula should be 0 04 taking into consideration the likely weed growth and the irregular shape it is likely to attain in due course
The minimum width at bottom shall not be less than 0.5 m and the minimum depth 0.60 m below ground level. It may also be verified if the drain is able to keep the water table normally below root zone depth of crops grown in the are i e about 1 meters below the farm level.
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Gradients: The gradients  should normally  follow the natural slope of the area. It should however be checked that the designed section gives  the non-silting and non scouring velocities.
7.8   Longitudinal Profile
The longitudinal profiles  for secondary  d rain RSD-15 and tertiary  drains. RTD 17-13 RTD-16-7 have been prepared and are available at draining number AD-F-C-RSD-15-1, RTD-17-13-1 and RTD-16-7-1 respectively.
7.9   Cross - Section of Drains
The  typical  cross-section  f  or  s  econdary  drain  RSD-15  a  nd  Tertiary  drainshave  been prepared and the same are available at relevant Drainings for the longitudinal profiles.
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Table 7.1: -Details of Secondary Drains-Naturally existing or proposed for construction
Riqht bank command area
Drainage
Channel
RSD-1 (N)
—1 “
Located
between
Before SC-1
SC-1& SC-2
SC-2& SC-3
SC-3 & SC-4
SC-4 & SC-5
S(>5 & SC-6
SC-6 & SC-7
Length of
artificial
channel (m)
Drainage
Channel
LSD-1 (N)
Left bank command area
Located between
Within Sc-1
Length of
artificial
channel (m)
RSD-2 (C) RSD-3 &4(N} RSD-5 (N) RSD-6 (C) RSD-7 (C) RSD-8 (N)
731
LSD-4 (N)
LSD-5 (N)
LSD-6 (N)
LSD-7 (C)
LSD-8 (N)
LSD-9 (N)
SC>2& SC-3
SC-3& SC-4
SC-4& SC-5
Beyond SC-6
Before SC-7
SC-8& SC-9
SC-9& SC-10
RSD-14 (N)
RSD-15 (C) RSD-16 (N£ RSD-17 (N) RSD-187cj~ RSD-19 (N) RSD-20 (N) RSD-21 (N) RSD-22 (N)
SC-10 & SC-11
SC-11 & SC-12
SC-12 & SC-13
SC-13&  SC-14
SC-14 & SC-15
SC-15 & SC-16
SC-16 & SC-17
SC-17 & SC-18
SC-18 & SC-19
SC-19 & SC-20
SC-20 & SC-21
SC-21 & SC-22
686 637
1345 1165 1044 1982 1525
LSD-10 (N)
LSD-11 (N)
LSD-12 (NJ 
LSD-13 (N)
LSD-14 (N)
LSD-15 (N1
LSD-16 (N)
LSD-17 (N)
LSD-18 (N)
LSD-19 (N)
LSD-20 (C)
LSD-21 (N)
LSD-22 (C)
LSD-23 (N)
LSD-24 (N)
LSD-25 (Nj
SC-10& SC-11
Before SC-12
SC-12&SC-13
SC-13, SC14& SC-15
SC-15& SC-15
SC-16& SC-17
SC-17& SC-18
SC-13& SC-19
SC-19& SC-20 ~
SC-20& SC-21
SC-22& SC-23
S  SCC- -2234&&SSCC--2245
RSD-23 (C) RSD-24JN) RSD^gSJC) RSD-26 (N£ RSD-27 (N) RSD-28 (N) RSD-29 (C) RSD-30 (N£ RSD-31 (CJ_ RSD-32_(C) RSD-33 (NJ RSD-34 (N) RSD-35  (C) RSD-36  (N) RSD-37  (N) RSD-38 (N)_ RSD-39 (NJ
SC-22 & SC-23
SC-23 & SC-24
SC-24 & SC-25        1136
SC-25 & SC-26 SC-26 & SC 27
2
SC-27 & SC-28
SC-28 & SC-29
SC-29 & SC-30
SC-30 & SC-31
SC-31 & SC-32
SC-32 & SC-33
SC- 33& SC-34
SC-34 & SC-35
SC-35 & SC-36
1320
2589
-
2156 1914
, SC-36 & SCJ37 1975
SC237 & SC-38
j~SC~38 & SC-39
SC-39  &  SC-40
Beyond SC- 40
h
LSD-26 (N) LSD-27 (N) LSD-28 (N)
I  LSD-29  (N)_ ^LSDWJ TTSD-31   (N)_ ~TsD^327N)
LSD-33JN1 _ LSD-34IN) LSD-35 (N) LSD-36 N) LSD-37 (N) LSD-J8 N i
“ LSD-39 (N) LSD-40 (N) LSfMIJN] LSD-4 2 (N)
' SC-25& SC-26
Within SC-26
Within SC-26
" SC-26& SC-27
Before SC-28
SC-28& SC-29
SC-29& SC-30
' SC-30& SC-31______
SC-31 & S(>32
SC-32& SC-33
SC-34& SC-35
SC-35& SC-36
SC-368. SC-37
Beyond SC-38
Before SC-39a
SC-39a& SC-39b Within       ScJ9b—__ SC-39b&SC-40_____ SC-40&SC>4j______ SC-41 & SC-42____
i SC-42& SC-43 _ . ' SC-43& SC-44____
-+SC44& SC-45_ Beyond_SC>45_
N = Naturally existing
C = Proposed for construction.
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Table 7.2: -Hydraulic particulars for Secondary Drain RSD-15
Rogosity  coefficient  (Manning's  n  =  0.0225)
Canal side slope (1.5:1 for cut & 2:1 for fill)
May 2007
SI.
no
Cumulative
distance in
m
Progressive
discharge in
canal
Bed
width
(m)
F.S.D
(m)
Velocity
(V = m/s)
Canal
bed
slope
Critical
velocity (V9)
= 0.546D°^4
=m/s
v/v0
Wetted
perimeter
2
0
0.025
0.3
0.21
0.198
0.00033
0.201
0.985
1.05
3
180
0.08
0.3
0.36
0.266
0.00033
0.284
0 937
1.59
4
411
0.109
0.3
0.41
0.287
0.00033
0.309
0.93
5
544
0.166
0.5
0.45
0.318
0.00033
0.328
0.97
2.11
6
734
0.197
0.5
0.48
0.332
0.00033
0.341
0.974
2.24
7
856
0.267
0.6
0.53
0.358
0.00033
0.364
0.98
2.52
8
981
0.31
0.7
0.53
0.378
0.00033
0.372
1.02
2.68
9
1174
0.382
0.8
0.58
0.391
0.00033
0.385
1.02
2.9
10
1230
0.444
0.8
0.63
0.406
0.00033
0.406
0.999
3.06
11
1456
0.519
0.8
0.68
0.421
0.00033
0.427
0.985
3.24
12
1527
0.618
1.00
0.74
0.397
0.00025
0.45
0.88
3.66
13
1734
0.723
1.00
0.8
0.414
0.00025
0.47
0.875
3.87
I 14
1756
0.799
1.00
0.84
0.424
0.00025
0.488
0.868
4.01
1 15
1982
0.799
1.00
0.84
0 424
0.00025
0 488
0 868
4 01
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Table 7.3: - Hydraulic particulars for Tertiary drains in sample area Manning's coefficient n= 0.0225
Side Slope = 1.5:1 in cut, 2:1 in fill
One-day maximum of 5years frequency rainfall (R= 66mm) ARF _ J x 10000x0,066x0.50 _ 330/1
May 2007
T”
24x3600
” 86400
S no
Name of Block (secondar y canal)
Tertiary canal
C.C.A
in ha
Design flood
Q=m7s
Bed
widt
h in
m
FS.D in
m
Velocit
y (rn/s)
Vo
V/ Vo
T
1
RTD-16-1
21.33
0.081
0.40
0.34
0.266
0.274
0.97
2
RTD-16-2
14.28
0.055
0.30
0.30
0.241
0 284
0.954
3
RTD-16-3
25.13
0.096
0.40
0.36
0.278
0.284
0.979
4
RTD-16-4
14.91
0.057
0.30
0.30
0.244
0.253
0.954
5
RTD-16-5
29.63
0.113
0.40
0..39
0.297
0 299
0.97
6
RTD-16-6
18.42
0.070
030
0.34
0. 257
0 274
0.939
7
RSD-16
RTD-16-7
32.85
0.125
0.40
0.41
0.297
0 309
0.962
8
RTD-16-8
18.96
0.072
0.30
0.34
0.259
0.274
0.945
9
RTD-16-9
35.71
0.136
0.40
0.43
0.303
0.318
0 952
10
RTD-16-10
19.51
0.075
0.30
0.35
0.262
0.279
0.940
11
RTD-16-11
34.85
0.133
0.40
0.45
0.302
0.327
0.92
12
RTD-16-12
19.88
0.076
030
0.35
0.262
0.279
13
0 940
RTD-16-13
28
0.107
0 40
0.38
0.286
0.984
0.973
19
RTD-17-1
6.5
0.025
0.30
0.21
0.198
20
0.201
0.984
RTD-17-2
9.73
0.037
0.30
0.25
21
0.218
0.225
RTD-17-3
7.57
0.029
0.970
0.30
0.22
22
0.205
0 207
RTD-17-4
19.77
0 076
0.989
0.30
0.35
0.262
23
0.279
RTD-17-5
8.2
0.031
0940
0.30
0.23
24
0 208
RTD-17-6
21.84
0 083
0.213
0.40
0.976
0.34
25
0.267
RTD-17-7
0.274
11.24
0 043
0.30
0.974
0.27
r 26
0.227
RTD-17-8
20.54
0.078
0.236
0.30
0.35
0.961
27
0.264
RTD-17-9
0.279
16.32
0.062
0.30
0.946
0.32
28
0.249
RTD-17-10
20
0.076
0 263
0.30
29
RSD-17
0.35
0 946
0.262
RTD-17-11
25.94
0.099
0.40
0279
31
0.37
0 280
RTD-17-12
19.89
0.076
0.30
0.289
0 35
.
0 969
0 940
32
0.262
RTD-17-13
27.45
0.105
0 40
0.279
33
0.38
.
0 940
0.284
RTD-17-14
19.64
0.075
0.30
0.294
0 966
34
035
0 262
RTD-17-15
37.44
0.143
0.40
0.279
0 44
0 940
rss
20.77
0.079
0.307
RTD-17-16
0.30
0 322
0 36
0 950
36
37
RTD-17-17
RTD 17 18
25.48
21 54
0.097
0 082
0.265
0 40
0 40
0.284
0.962
38
--
RTD-17-19
037 U
0 933
0.278
0.289
21.15
0.081
0 40
39
.
0.34
0.267
0.266
0.274
0 274
0.97
O Q7A
_________
RTD-17-20
21.63
0.083
040
0 34
0.267
H).274
097
Water Works Design & Supervision Enterprise "            ~
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8 FARM DEVELOPMENT WORKS AND WATER MANAGEMENT
8.1  General
It has  been observed that the development of irrigation takes  long time after implementation of the irrigation project is  completed. The development of irrigation includes  the spread of irrigation in every  nook  and corner of the envisaged command area; optimal utilization and equitable distribution of irrigation water among all farmers (big or small); in entire command area (including head and tail reaches) thereby  optimal production on available land with available irrigation water. In most of irrigation projects irrigation development has  taken several decades. Even after several decades  the achievement is  not satisfactory  and the scheme suffers  from serious  deficiencies. In order to avoid occurrence of these deficiencies  and achieve fast development of irrigation for optimum production and accrual of benefit, it has  been realized that the following items  are considered very  essential and as  such these should be implemented at the earliest:
- On -farm development (OFD) work
Development of Infrastructures
Water management
8.2  Farm Development Work
Irrigation Projects  are being implemented with considerable investment justified on the basis  of envisaged significant increase in yields. The delay  in accrual of benefits  and/or accrual of benefits  in magnitude smaller than envisaged, have very  adverse economic impact. It has been now realized that for the accrual of benefits from irrigation project, it is  essential that farm development works  are also planned, implemented and maintained properly  The farm development works  can be sub-divided into the following two categories.
-    On-Farm development works, which are popularly called as OFD works; and
-    Off-Farm development works, which are popularly know as infrastructures 8.2.1  On-Farm Development (OFD) Works
On-Farm Development works comprises the following:
i)   Construction, maintenance and operation of field canals for delivering
irrigation water to every field/farm
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ii)           Construction,  maintenance  and  operation  of  field  drains  for  removing excess water from rain or irrigation from every field/farm.
iii)          Construction  and  maintenance  of  field  road  (access  track)  to  provide access  to  every  field/farm  for  transportation  of  implements  and  inputs to the field/farm and produce from the field/farm to the storage/market.
iv)         Shaping,  leveling  and  grading  of  fields/farms  for  efficient  application  of irrigation  water  as  well  as  efficient  removal  of  rain  or  irrigation  water from the fields/farms.
v)           Evolving  and  adopting  operational  procedure  for  equitable  distribution of  irrigation  water  to  various  fields/farms  served  by  an  individual  field canal.
8.2.1.1   Planning for On-Farm Development works
The planning for On-Farm Development works should satisfy the following criteria: i)          The design of water distribution system should facilitate equitable and
efficient distribution and control of irrigation water to each field/farm.
ii)
The design of drainage system should facilitate timely and efficient removal of
excess rain or irrigation water from every field/farm
iii)
The field layout and land preparation should facilitate the use of machinery in
cultivation, harvesting etc. to enable efficient soil and water management.
iv)
It should conserve soil and water and prevent water logging.
v)
The plan should minimize the cost of execution of work and loss of area
under bunds, channels and drainage.
8.2.1.2   Provision at Feasibility Study Level
In the Feasibility  Study, planning has  been done to provide irrigation and drainage channels  upto quaternary  levels, which means  that irrigation and drainage channels  are available upto 1.5 ha of field. However, they  will have to be taken to even smaller holdings  say  0.5 ha or even smaller. As  regards  land clearance and land leveling provisions  has  already  been made in the cost estimate at Feasibility  Study  for the entire command area. However, further refinement will be required at farmer level during actual operation. Drainage system has  already  been planned which will be able to avoid waterlogging. As regards evolving and a dopting o perational procedure for equitable
____________________________________________________________________________86 Water Works Design & Supervision Enterprise
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distributions of irrigation water to various fields/farms, several innovative measures i n form of hardwares like provisions of Adjustable Proportional Modular Outlet, flexibility factors  in design of canal capacities  etc  and softwares  in form of Rotational Water supply  at macro level (secondary  canal) and turn-by-turn supply  for fixed time in proportion to real farm area have already  been proposed at Feasibility  Study  level. However all these aspects  will be further refined at the time of detailed design, implementation and actual operation of the system. It is  expected that by  that time Participatory  Irrigation Management, which is  expected to play  significant role in all these aspects, will be able to take some shape.
8.2.2 Off-Farm Development Works
Off-Farm Development works  are related to development of Infrastructures. With the introduction of irrigation a large number of activities, which have forward and backward linkages, will develop in and around command area. In order to ensure the envisaged increase in yield, it is  essential that proper arrangement should be made to make available in-puts  like implements, seed, fertilizer, pesticide, loan for working capital. Similarly with increase in agricultural production it will be required to make arrangements for processing, storage, transport, marketing etc. For this the concerned organizations, institutions  at different levels  will have be organized, developed and their proper functioning will have to be ensured
8.3 Water management
Water Management involves a very broad spectrum of activities. With the introduction of irrigation it is  envisaged to achieve optimum agricultural production. It involves transformation of traditional farming system into intensively  irrigated agriculture, high with input level of fertilizer, pesticide etc  with intensive labour and high capital investment. This  is  a gradual process  a nd requires  a very  close interaction between irrigation system being maintained and operated by irrigation engineers and agriculture system in which farmers  along with the agriculture scientist in-charge of extension services  are involved In this  context Water Management is  expected to play  a significant role.
The objective of water management is to obtain optimum yield sustained on long term
With conservation of water, soil and fertility of the land without any adverse
environmental impact.
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Water Management aspect of an irrigation and drainage project basically addresses to three important questions:
i)         how to irrigate (method of irrigation);
ii)        When to irrigate (timing or interval);
iii)       How much to irrigate (depth or volume of water);
Water management involves operation of the canal system from primary to field canal for conveyance, distribution and application of irrigation water to the field. It requires three steps:
i) Estimation of demand for irrigation water at field level in the background of
(a) prevailing agro climatic factors,
(b) stage of growth of crop and
(c) Soil characteristics;
ii) Application of required (as assessed) quantity of water; and
iii) Assessment of the performance and impact for modification, if necessary.
8.3.1  Irrigation Schedule
During detailed design and actual operation of the canal system, irrigation schedule will be prepared, which will form the basis for the actual operation of the system. While preparing irrigation schedule, the following should be taken into consideration.
Climatic factor in form of Reference Evapotranspiration
-    Crop characteristics
o Stage of growth of crop
o Rooting depth
-    Soil Characteristics
o Water holding capacity
-    Irrigation Efficiency
8.3.2  Operation & Maintenance Manual
A detailed Manual for Operation & Maintenance of the Irrigation System should be prepared. While preparing this Manual, the following will be taken into considerations 
Rotational Water Supply at macro-level (secondary canal level)
- Turn-by-Turn water supply for fixed duration in proportion to the area of
individual field at farm level
Introduction of Participatory Irrigation management
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Summery

Arjo-Dedessa Irrigation Project Summary

Arjo-Dedessa Irrigation Project Feasibility Study Summary

Project Overview

The Arjo-Dedessa Irrigation Project is a major agricultural development initiative in Ethiopia, located in the Illubabor and Eastern Welega zones. The project involves:

Construction of a 40.6m high earth & rock fill dam with 1341.2 Mm³ gross storage capacity
Development of irrigation systems for 17,825ha gross command area (13,665ha culturable)
Implementation of comprehensive water management systems
Integration of agricultural development with irrigation infrastructure

The project is being implemented by the Ministry of Water Resources of Ethiopia with technical assistance from Water Works Design & Supervision Enterprise and Intercontinental Consultants and Technocrats Pvt. Ltd.

Key Components

1. Dam and Appurtenant Works

Earth and rock fill dam (40.6m high)
Gross storage: 1341.2 Mm³
Live storage: 466.5 Mm³
Full Reservoir Level (FRL): EL 1356m
Minimum Draw Down Level (MDDL): EL 1350m

2. Irrigation System

Canal Type	Quantity	Total Length	Max Discharge
Right Primary Canal	1	44 km	7.52 m³/s
Left Primary Canal	1	60 km	9.015 m³/s
Secondary Canals (Right)	40	49.37 km	0.04-0.69 m³/s
Secondary Canals (Left)	45	47.95 km	0.022-1.206 m³/s

Command Area Details

Total Gross Command Area: 17,825 ha (Right Bank: 6,827 ha, Left Bank: 10,998 ha)

Culturable Command Area: 13,665 ha (76.67% of GCA)

Land Characteristics

Topography: Elevation varies between 1348 to 1330 amsl
Slopes: 45% level (0-1%), 7% nearly level (1-2%), 28% very gentle (2-4%), 20% gentle (4-6%)
Soil types: 48% Vertisols, 24.5% Luvisols/Cambisols/Nitisols, 27.4% miscellaneous

Land Suitability for Crops

Crop	Suitable Area (ha)
Rice	4,428.05
Wheat	1,639.60
Maize	1,639.60
Sugarcane	2,986.33
Vegetables	12,755.44
Pasture	2,114.56

Water Requirements

Crop Water Requirements

The study calculated water requirements for different crop rotations in two phases:

Phase I (126-138% cropping intensity)

Annual water requirement: 987-1,086 mm
Peak duty: 0.703-0.840 l/s/ha

Phase II (156-173% cropping intensity)

Annual water requirement: 1,311-1,423 mm
Peak duty: 0.915-1.056 l/s/ha

Water Quality

Water quality analysis of Dedessa River shows:

pH: 6.7 (within suitable range)
Total dissolved solids: 60-90 mg/l (below 300 mg/l limit)
Sodium Absorption Ratio (SAR): 0.26-0.43 (excellent for irrigation)

Key Design Features

Irrigation System Design

Unlined earthen canals for all components (primary to quaternary)
Proposed overall irrigation efficiency: 50% for paddy, 40% for other crops
Flexibility factors incorporated (10-25% additional capacity)
Check basin irrigation method proposed

Drainage System

Comprehensive drainage system planned to prevent waterlogging, including:

Field drains
Tertiary drains
Secondary drains

Innovative Features

Rotational water supply at secondary canal level
Turn-by-turn water distribution at field level
Participatory Irrigation Management (PIM) approach
Special structures like adjustable proportional modular outlets

Implementation Approach

Phased Development

The project proposes two phases of agricultural development:

Phase	Cropping Intensity	Key Features
Phase I	126-138%	Basic irrigation infrastructure, establishment of cropping patterns
Phase II	156-173%	Intensified cropping, improved water management, full PIM implementation

Sample Area Development

A 756ha sample area was selected for detailed micro-irrigation planning, including:

Complete tertiary and quaternary canal network design
Detailed drainage system layout
Field-level water distribution planning