Hydraulic Gradient Calculator
Work out the hydraulic gradient – the change in hydraulic head over a given flow length – used in groundwater flow, drainage, and pipe design.
What the hydraulic gradient is
The hydraulic gradient is the change in hydraulic head (water elevation potential) per unit distance along the direction of flow. It is the driving force behind groundwater movement and behind head loss along pipes and channels, and it is dimensionless – a ratio of length to length.
The formula
The gradient is calculated as i = Δh / L, where Δh is the difference in hydraulic head between two points and L is the distance between them measured along the flow path. A larger gradient means water is being driven with greater force over that distance.
This calculator is intended for general engineering and educational reference; real groundwater and pipe-flow analysis should also account for soil permeability (via Darcy’s Law) or pipe friction factors as appropriate.