This standard provides guidelines for the hydraulic and structural design of canals lined with rigid materials like concrete, shotcrete, or masonry. It covers the selection of lining type, determination of canal geometry, freeboard requirements, lining thickness, and details for joints and drainage.
Provides guidelines for the planning, investigation, and design of irrigation canals with rigid linings (e.g., concrete, brick masonry).
Quick Reference Values
Manning's 'n' for cement concrete lining0.014 - 0.018 (Table 1)
Typical side slope for concrete lining in ordinary soils1.5H : 1V (Table 3)
Minimum freeboard for canals with discharge < 10 cumecs0.50 m (Table 4)
Minimum thickness for in-situ concrete lining (Discharge > 10 cumecs)100 mm (Clause 7.2)
Maximum permissible velocity for concrete lining2.5 m/s (Table 2)
Recommended spacing of contraction joints4.5 m (Clause 8.3.1)
Key Formulas
V = (1/n) * R^(2/3) * S^(1/2) — Manning's formula for velocity
Q = A * V — Continuity equation for discharge
Practical Notes
Drainage behind the lining (sub-surface drainage) is critical to prevent damage from external water pressure, especially during canal drawdown. See Clause 9.
The choice of Manning's roughness coefficient 'n' should be done carefully, considering the quality of workmanship and potential for future surface degradation.
Proper curing of concrete lining is essential to minimize shrinkage cracks and achieve desired durability and impermeability.