This standard outlines the criteria for the hydraulic and structural design of head regulators and cross regulators used in canal systems. It provides guidelines for determining waterway, crest levels, foundation design based on seepage theories, and scour protection measures.
Provides criteria for the hydraulic and structural design of head regulators and cross regulators for canals.
Quick Reference Values
Minimum freeboard above FSL0.75 m
Minimum top width of piers0.2 times the head over crest, subject to a minimum of 0.75 m
Typical Coefficient of discharge (Broad crested weir)1.71
Maximum permissible exit gradient for fine sand1/6 to 1/7
Recommended afflux for cross regulators0.15 m to 0.3 m
Key Formulas
Q = C * Le * H^(3/2) — Discharge formula for a broad-crested weir
GE = (H/d) * (1 / (π * sqrt(λ))) — Khosla's exit gradient formula
Pu = γw * h — Uplift pressure at a point
Practical Notes
The choice of foundation design method (Bligh's creep theory, Lane's weighted creep theory, or Khosla's theory) is critical and depends on the importance of the structure and subsoil conditions. Khosla's theory is generally preferred for major works.
Accurate assessment of the foundation soil properties and the design high flood level (HFL) are paramount for a safe and economical design.
Adequate scour protection works, such as launching aprons and concrete blocks upstream and downstream, are essential for the long-term stability of the structure.