Technical Guideline For Design Of Irrigation Canal And .

Japan International Cooperation Agency (JICA)Oromia Irrigation Development Authority (OIDA)Technical Guideline for Design ofIrrigation Canal and Related StructuresMay, 2014The Project for Capacity Building in Irrigation Development (CBID)

ForewordOromia Irrigation Development Authority (OIDA) is established on June,2013, as a responsible body for all irrigation development activities in theRegion, according to Oromia National Regional Government proclamationNo. 180/2005. The major purposes of the establishment are to accelerateirrigation development in the Region, utilize limited resources efficiently,coordinate all irrigation development activities under one institution withmore efficiency and effectiveness.To improve irrigation development activities in the Region, the previousOromia Water Mineral and Energy Bureau entered into an agreement withJapan International Cooperation Agency (JICA) for “The Project for CapacityBuilding in Irrigation Development (CBID)” since June, 2009 until May,2014. CBID put much effort to capacitate Irrigation experts in OromiaRegion through several activities and finally made fruitful results forirrigation development. Accordingly, irrigation projects are constructed andrehabilitated based on that several Guidelines & Manuals and textsproduced which can result in a radical change when implemented properly.Herewith this massage, I emphasize that from Now on, OIDA to make effortsto utilize all outputs of the project for all irrigation activities as a minimumstandard, especially for the enhancement of irrigation technical capacity.I believe that all OIDA irrigation experts work very hard with their respectivedisciplines using CBID outputs to improve the life standard of all people. Inaddition, I encourage that all other Ethiopian regions to benefit from theoutputs.Finally, I would like to thank the Japanese Government, JICA EthiopiaOffice, and all Japanese and Ethiopian experts who made great effort toproduce these outputs.Feyisa Asefa AdugnaAddis Ababa, EthiopiaMay, 2014General ManagerOromiaIrrigationAuthorityDevelopment

Introductory Remarks“Growth and Transformation Plan” (GTP) from 2011 to 2015 intensifies use ofthe country’s water and other natural resources to promote multiple cropping,better adaptation to climate variability and ensure food security. Expansion ofsmall scale irrigation schemes is given a priority, while attention is also givento medium and large scale irrigation.In Oromia Region, it is estimated that there exists more than 1.7 million ha ofland suitable for irrigation development. However, only 800,000 ha is underirrigation through Traditional and Modern irrigation technology. To acceleratespeed of Irrigation Development, the Oromia National Regional State requestedJapan International Cooperation Agency (JICA) for support on capacitybuilding of Irrigation Experts under Irrigation Sector.In response to the requests, JICA had conducted "Study on Meki Irrigation andRural Development" (from September 2000 to January 2002) and Project forIrrigation Farming Improvement (IFI project) (from September 2005 to August2008). After implementation of them there are needs to improve situation onirrigation sector in Oromia Region.JICA and the Government of Ethiopia agreed to implement a new project,named “The project for Capacity Building in Irrigation Development” (CBID).The period of CBID is five years since June, 2009 to May, 2014 and mainpurpose is to enhance capacity of Irrigation Experts in Oromia Region focusingon the following three areas, 1) Water resources planning, 2)Study/Design/Construction management, 3) Scheme management throughTraining, On the Job Training at site level, Workshops, Field Visit and so onand to produce standard guidelines and manuals for Irrigaiton Development.These guidelines and manuals (Total: fourteen (14) guidelines and manuals)are one of the most important outputs of CBID. They are produced asstandards of Irrigation Development in Oromia Region through collectingdifferent experiences and implementation of activities by CBID together withOromia Irrigation Experts and Japanese Experts.These guidelines and manuals are very useful to improve the Capacity of OIDAExperts to work more effectively and efficiently and also can accelerateIrrigation Development specially in Oromia Region and generally in the country.Finally, I strongly demand all Irrigaiton Experts in the region to follow theguidelines and manuals for all steps of Irrigation Development for sustainabledevelopment of irrigation.Adugna Jabessa ShubaAddis Ababa, EthiopiaMay, 2014D/General Manager & Head, Study,Design, Contract Administration &Construction SupervisionOromiaAuthorityIrrigationDevelopment

Table of Contents1. GENERAL DESCRIPTION. 11.1 Aim of the Manual . 11.2 Scope of the Manual . 11.2.1 Classification of Canals and Application. 11.2.2 Fluid. 21.3 Classification of Canals . 21.3.1 Classification by Purpose. 2(1) Irrigation canal . 2(2) Drainage canal . 2(3) Dual-purpose canal (for irrigation and drainage) . 21.3.2 Classification by System . 31.3.3 Classification by Type . 3(1) Open channel type . 3(2) Pipe line type . 41.4 Canal System . 41.4.1 Water Conveying Facilities . 41.4.2 Diversion Facility, Water Measuring Facility and Canal JunctionFacility. 41.4.3 Regulating Facilities . 51.4.4 Protection Facilities . 51.4.5 Safety Facilities. 51.4.6 Operation and Maintenance Facilities. 51.4.7 Appurtenant Facilities . 51.4.8 Other related Facilities for Water Utilization. 51.5 Basic Considerations in Canal Design . 61.5.1 Basic Considerations in Design . 6(1) Information necessary for design . 6(2) Basic considerations in design of canals . 7i

1.5.2 Consideration of Rules related to Canal Design . 71.6 Basic Considerations in Canal Construction . 71.6.1 Basic Consideration in Canal Construction . 71.6.2 Construction . 82. BASIC DESIGN INPUT DATA (INVESTIGATION) . 92.1 Basic Consideration in Investigation . 92.1.1 Plan of Investigations . 9(1) General items . 9(2) Steps of investigation. 102.1.2 Items for Investigation. 11(1) Investigation items for overall plan . 11(2) Investigation items for design and construction. 11(3) Investigation items for operation and maintenance . 12(4) Other investigation items . 122.2 Investigations . 122.2.1 Topographical Investigations and Surveys . 12(1) Data collection . 13(2) Aerial photographic survey. 13(3) Route survey. 132.2.2 Soil and Geological Investigations. 16(1) Items and methods of investigations . 16(2) Investigation for overall plan. 22(3) Pre-feasibility study . 22(4) Feasibility study . 252.2.3 Meteorological and Hydrological Investigations . 29(1) General . 29(2) Meteorology . 29(3) Hydrology . 30(4) Others. 31ii

2.2.4 Investigations of Site Conditions. 32(1) General . 32(2) Investigation on social conditions. 32(3) Investigation of construction conditions. 33(4) Environmental investigation. 342.2.5 Investigation on Water Management andOperation and Maintenance of the Canal System . 343. DESIGN CONCEPTS . 353.1 General . 353.1.1 General Concepts. 35(1) Overall design of irrigation canal . 35(2) Overall design of drainage canal. 35(3) Main items to be considered in overall design. 36(4) Canal or structure design. 373.1.2 Procedure of Design . 373.1.3 Design Discharge and Designed Level . 41(1) Design discharge . 41(2) Designed level . 423.1.4 Selection of Canal Type. 43(1) Open channel type . 44(2) Pipeline type . 44(3) Compound type of open channels and pipelines . 453.1.5 Canal Route Selection. 46(1) General conception for the canal route selection . 46(2) General condition for the canal route selection . 46(3) Procedure for canal route selection . 483.1.6 Selection of Canal Structures for Open Channel Type . 49(1) Open channel . 49(2) Tunnel . 50iii

(3) Culvert . 51(4) Siphon/aqueduct . 52(5) Drop/chute . 533.1.7 Particulars to be considered in Selection ofCanal Route and Structures . 54(1) Minimum radius of curve . 54(2) Limitation of longitudinal slope and curve . 56(3) Minimum earth cover . 573.2 Hydraulic Design. 583.2.1 General . 58(1) Hydraulic design of canals . 58(2) Establishment of the hydraulic consistency in the canal design . 593.2.2 Allowable Flow Velocity . 59(1) Determination of the design velocity . 59(2) Minimum allowable velocity . 59(3) Maximum allowable velocity. 60(4) Considerations for determination of design velocity . 613.2.3 Calculation of Mean Velocity . 62(1) Discharge of canal . 62(2) Mean velocity formula of open channel type canal. 62(3) Coefficient of roughness . 62(4) Determination of cross-section area of a uniform flow canal . 68(5) Mean Velocity Formula of a Pipeline Type Canal . 683.2.4 Non–uniform Flow . 69(1) Basic equation of non-uniform flow (reference) . 69(2) Critical depth . 70(3) Head losses and change of water level . 72(4) Various head losses. 73(5) Head loss and change of water level due to change of canalSection . 74iv

3.3 Structural Design . 803.3.1 General . 803.3.2 Load . 80(1) Dead weight . 80(2) Water pressure . 81(3) Buoyancy and up-lift . 81(4) Earth pressure . 82(5) Vehicle load and impact load. 82(6) Crowd loads. 88(7) Track loads . 89(8) Earthquake load (reference) . 89(9) Wind pressure load . 90(10) Construction load . 90(11) Temperature stresses . 90(12) Drying shrinkage and creep of concrete . 90(13) Frost heave pressure . 913.3.3 Reaction of Foundations . 91(1) When a uniform load acts on normal (compressive) ground. 91(2) In the case of an eccentric load . 913.3.4 Loads Acting on Open Channels . 93(1) Load combination. 93(2) Soil constant. 94(3) Load applied to vertical walls. 953.3.5 Stability Analysis . 108(1) Reviews for overturning . 108(2) Reviews for sliding . 109(3) Reviews for foundation ground bearing capacity . 1093.3.6 Plain and Reinforced Concrete . 110(1) Types of reinforcing bars . 110(2) Allowable stresses. 111v

(3) Design of reinforced concrete . 115(4) Minimum thickness of members. 121(5) Joints. 121(6) Cut-off walls . 123(7) Haunches . 1233.4 Detail Designs for Canals and Related Structures . 1253.4.1 Basics of Design. 125(1) Cross-sectional forms of open channels (Hydraulically favorablecross-sections). 125(2) Freeboard . 126(3) Treatment for the foundation ground. 134(4) Earth works.

Technical Guideline for Design of Irrigation Canal and Related Structures May, 2014 The Project for Capacity Building in Irrigation Development (CBID) Foreword Oromia Irrigation Development Authority (OIDA) is established on June, 2013, as a responsible body for all irrigation development activities in the