7. Irrigation and Drainage

7. Irrigation and Drainage

7.1 Water Demand Estimation

• Crop Water and Irrigation Water Requirements

• Water Availability for Irrigation, Command Areas

• Irrigation Intensity, Duty, Delta and Their Relationship

• Water Losses and Irrigation Efficiencies

• Effective Rainfall

• Soil-Moisture-Irrigation Relationship

• Depth and Frequency of Irrigation

• Design Discharge for Canals

7.2 Design of Canals

• Canal Types, Network and Alignment

• Tractive Force Approach of Canal Design

• Design of Stable Canals

• Design of Alluvial Canals: Kennedy’s and Lacey’s Theory

• Design of Lined Canals

7.3 Diversion Headworks

• Components of Headwork

• Seepage Theories and Applications: Bligh’s, Lane’s, Khosla’s

• Design of Silt Control Structures: Excluder, Ejector, Settling Basins

• Design of Weir/Barrage: Crest, Length and Thickness of Impervious Floor

• Design of Energy Dissipaters

7.4 River Training Works

• River Stages and Need of River Training

• Design of River Training Works: Guide Bund and Launching Aprons, Levees, Spurs

• Watershed Management

7.5 Regulating and Cross-Drainage Structures

• Functions of Various Types of Regulators

• Design of Regulators and Escapes: Crest, Length and Thickness of Impervious Floor

• Design of Pipe Outlet: Free and Submerged

• Design of Vertical Drop: Crest, Length, and Thickness of Impervious Floor

• Design of Cross-Drainage Structures

7.6 Water Logging and Drainage

• Causes, Effects and Preventive Measures

• Design of Surface and Sub-surface Drainage Systems