IS 10432:1982 is the Indian Standard (BIS) for criteria for design of barrages and weirs. This standard provides criteria for the hydraulic and structural design of barrages and weirs. It covers aspects from site investigation and data collection to the detailed design of components like the weir profile, impervious floor, and energy dissipation devices, based on established theories like Bligh's and Khosla's.
Lays down criteria for the hydraulic and structural design of barrages and weirs across rivers for diversion of water.
Key hydraulic design formulae, scour depths, safe exit gradients, creep coefficients, and dimensional criteria for barrages and weirs.
| Reference | Value | Clause |
|---|---|---|
| Lacey's Wetted Perimeter (P)— Where Q is the design flood discharge in m³/s. | 4.75 * √Q | Cl. 3.2.1.1 |
| Typical Afflux Limit— Final value depends on site conditions and upstream submergence. | 0.5 to 1.0 m | Cl. 3.3.1 |
| Discharge Coeff. (Broad-crested Weir)— For use in the formula Q = C * L * H^(3/2). | 1.71 | Cl. 3.4.2.1 |
| Discharge Coeff. (Ogee Spillway)— For use in the formula Q = C * L * H^(3/2). | 2.2 | Cl. 3.4.2.2 |
| Lacey's Scour Depth (Straight Reach)— Where q = discharge per metre width and f = silt factor. | R = 1.35 * (q²/f)^(1/3) | Cl. 3.5.2.1 |
| Scour Depth Factor (Moderate Bend) | 1.50 R | Cl. 3.5.2.1 |
| Scour Depth Factor (Severe Bend) | 1.75 R | Cl. 3.5.2.1 |
| Scour Depth Factor (Right-angled Bend) | 2.00 R | Cl. 3.5.2.1 |
| Safe Exit Gradient (Shingle) | 1/4 to 1/5 | Cl. 3.6.4.1 (Table 1) |
| Safe Exit Gradient (Coarse Sand) | 1/5 to 1/6 | Cl. 3.6.4.1 (Table 1) |
| Safe Exit Gradient (Fine Sand) | 1/6 to 1/7 | Cl. 3.6.4.1 (Table 1) |
| Floor Thickness against Uplift— Includes a factor of safety of 4/3. G is sp. gravity of floor material. | t = (4/3) * h / (G-1) | Cl. 3.6.5.1 |
| Bligh's Creep Coeff. (Coarse Sand)— Used to determine required creep length L = C * H. | 12 | Appendix A, Cl. A-1 (Table 2) |
| Bligh's Creep Coeff. (Fine Sand)— Used to determine required creep length L = C * H. | 18 | Appendix A, Cl. A-1 (Table 2) |
| Lane's Weighted Creep Ratio (Coarse Sand) | 5.0 | Appendix A, Cl. A-2 (Table 3) |
| Lane's Weighted Creep Ratio (Fine Sand) | 7.0 | Appendix A, Cl. A-2 (Table 3) |
| Min. Freeboard (Barrage)— Above pond level or high flood level, whichever governs. | 1.0 to 1.5 m | Cl. 4.2.1 |
| Divide Wall Top Width | 1.5 to 2.5 m | Cl. 4.5.1 |
| Fish Ladder Max. Slope | 1 in 10 | Cl. 6.1.1 |
| Fish Ladder Min. Water Depth | 1.0 m | Cl. 6.1.1 |
| Silt Excluder Tunnel Velocity | 2.0 to 3.5 m/s | Cl. 6.2.1 |
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Mass of Desaturated Base Felt | Min 245 g/m² (for Type 1, Hessian Base) | Min 254 g/m² (for Type I/#15 Felt) | ASTM D226/D226M |
| Mass of Saturant (as % of dry felt) | Min 160% (for Grade 1) | Min 140% | ASTM D226/D226M |
| Breaking Strength, Longitudinal | Min 175 N / 50 mm width (for Type 1, Hessian) | Min 5.2 kN/m (≈ 260 N / 50 mm width) (for Type I) | ASTM D226/D226M |
| Breaking Strength, Transverse | Min 125 N / 50 mm width (for Type 1, Hessian) | Min 2.6 kN/m (≈ 130 N / 50 mm width) (for Type I) | ASTM D226/D226M |
| Pliability Test | No cracking over a 20 mm mandrel at 10°C | No cracking over a 19 mm mandrel at 18°C | ASTM D226/D226M |
| Heat Resistance Test | No flow/blistering at 65°C for 2h (for coated felt) | Not specified in D226 (saturated only); ASTM D249 (coated felt) requires no flow at 80°C for 2h. | ASTM D249/D249M |
| Water Absorption | Max 5% by mass (for Type 1) | Not specified as a performance test; controlled via minimum saturation requirements. | ASTM D226/D226M |