Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

Flow Per Width Square Meters Per Second (m²/s)

Required number input.

Gravity Meters Per Second Squared (m/s²)

Required number input.

Critical depth of rectangular open-channel flow from unit-width discharge q: yc=(q²/g)^(1/3). The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Critical Depth Meters (m)

The resulting critical depth meters returned as a number.

• Hydraulic equations require consistent datum, fluid properties, geometry, roughness, flow regime, and loss coefficients. Cavitation, air entrainment, unsteady flow, fittings, sediment, free-surface effects, and pump behavior may require a network or numerical model.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Manning Flow Rate

  Open-channel discharge from Manning n, flow area, hydraulic radius and energy slope in SI units.

• Froude Number Open Channel

  Open-channel Froude number v/√(gD), where D is hydraulic depth.

• Hydraulic Jump Sequent Depth

  Downstream conjugate depth of a hydraulic jump in a horizontal rectangular channel from upstream depth and Froude number.