Irrigation and Drainage Engineering

Course Objectives:
This course is aimed at teaching students to develop know how in planning, design, development,  operation, maintenance & management of irrigation the demand analysis of irrigation, methods of irrigation, components of an irrigation system and layout of irrigation structures.  The course is designed to plan the irrigation system, to design irrigation structures and to manage the irrigation system. 

1. Introduction  [4 hours]
1. Definition, advantages and disadvantages of irrigation
2. Status and need of irrigation development in Nepal
3. Crops, their seasons and periods (Cropping pattern & intensity)
4. Commanded areas and Irrigation intensity
5. Methods of field irrigation and their suitability
6. Planning of irrigation projects

2. Irrigation Water Requirements [4 hours]
1. Relation between Duty, Delta and crop periods
2. Crop Water Requirements (Penman’s method)
3. Operational water requirements
4. Water losses due to seepage and evaporation
5. Effective Rainfall
6. Irrigation Water Requirements
7. Soil-Moisture-Irrigation Relationship
8. Depth and Frequency of Irrigation
9. Irrigation efficiencies
10. Design discharges for canals

3. Canal Irrigation System [3 hours]
1. Classification of canals
2. Components of a canal irrigation system
3. Alignment of canals
4. Alluvial and Non-alluvial canals
5. Canal standards and Balancing canal depth
6. Canal distribution system

4. Design of Canals [6 hours]
1. Design capacity of canals
2. Sediment transport in canals
3. Tractive Force approach of canal design
4. Design of stable canals
5. Design of Alluvial canals (Kennedy’s & Lacey’s Theory)
6. Design of lined canals with economic analysis

5. Diversion Headworks [8 hours]
1. Component parts of Weir/Barrage (Detail drawing)
2. Bligh’s, Lane’s and Khosla’s seepage theory
3. Design of sloping glacies weir bay (crest, length & thickness of impervious floor)
4. Design of Undersluice and Silt excluder
5. Design of Silt ejector
6. Design of Head Regulator (Crest, length & thickness of impervious floor)

6. River Training Works [4 hours]
1. River stages and Need of river training
2. Types of river training works
3. Design of Guide bunds and Launching apron
4. Design of Spurs (Layout geometry, length, spacing and cross-section)

7. Regulating Structures [6 hours]
1. Alignment of the off-taking channels
2. Function of Head regulator, Cross regulator, Outlet, Drop and Escapes
3. Design of Regulators & Escapes (Crest, length and thickness of impervious floor)
4. Types of Outlet, Design of pipe outlet (free and submerged)
5. Types of Drop, Design of Vertical drop (Crest, length and thickness of impervious floor)

8. Cross-Drainage structures [4 hours]
1. Types (Drawing and Selection)
2. Design of Siphon Aqueduct (Detail drawing, Drainage waterway & barrel, Canal waterway & Transition, Length & thickness of impervious floor and Protection works)

9. Water Logging and Drainage [6 hours]
1. Causes, effects and preventive measures of water logging
2. Water logging and drainage of irrigated land
3. Surface drainage systems and their design
1. Layout planning for Drainage
2. Internal drainage of Bunded fields
3. External drainage
4. Drain design (water level, maximum & minimum slopes and cross-sections)
5. Remodeling of existing natural drains
4. Subsurface drainage systems and their design
1. Layout of subsurface drainage system
2. Flow of ground water to drains and spacing of tile drains

Tutorials: [30 hours]

1. Duty, Delta and Period Relation  (1 hour) 
2. Irrigation Water Requirements    (2 hoours)
3. Soil-Moisture-Irrigation Relation and Irrigation Interval  (2 hours)
4. Balancing depth for excavating canals  (1 hour)
5. Design of stable canals  (1 hour)
6. Design of Alluvial canals (2 hours) 
7. Design of lined canals (1 hour)
8. Design of Guide Bunds and Launching Apron  (2 hours) 
9. Design of hydraulic structures using Khosla’s Seepage Theory  (4 hours)
10. Design of sloping glacies Weir bay   (2 hours) 
11. Design of Cross & Head Regulators (3 hours)
12. Design of pipe outlet (1 hour)
13. Design of Vertical Drop (2 hpurs)
14. Design of Siphon Aqueduct   (4 hours)
15. Design of surface and sub-surface drains (2 hours)

Assignments & Field Visit:

1. Individual assignment on Irrigation Water Requirement using CROPWAT Software
2. Field visit of an Irrigation System, group presentation and submission of individual report

Reference books:

1. “Theory and design of irrigation structures”, volume I and II, R S Varshney, S C Gupta and R L Gupta, Nem Chand and Bros., Roorkee, 1979
2. Irrigation Engineering and Hydraulic Structures, S K Garg, Delhi, 1983
3. Irrigation Engineering, Gurcharan Singh
4. Design Manuals for Irrigation projects in Nepal, PDSP Manuals, M.9 Drainage Manual, 1990
5. Hydraulic Structures, P. Novak et.al., SPON PRESS, 2001

Evaluation Scheme:
The questions will cover all the chapters of the syllabus. The evaluation scheme will be as indicated in the table below.