Hydraulic Gradient Calculator

Your details

Choose which quantity to solve for. All other inputs become known values.
Total hydraulic head at the upstream (higher-head) measurement point.
m
Total hydraulic head at the downstream (lower-head) measurement point.
m
Straight-line or along-path distance between the two measurement points.
m
Hydraulic gradient (i)Steep gradient
0.2

Dimensionless ratio of head loss to flow path length (m/m or ft/ft)

Head loss (dh)6m
Gradient as slope20%
Upstream head (h1)10m
Downstream head (h2)4m
Flow path length (L)30m
0.2 m/m
Gentle<0.01Moderate0.01-0.1Steep0.1-0.3Critical zone0.3+

Hydraulic gradient i = 0.2000 (20.00% slope).

  • For every m of horizontal distance, the hydraulic head changes by 0.2000 m.
  • A steep gradient indicates a large head difference over a short distance. Verify that soil or pipe material can handle the resulting flow velocities without erosion or piping failure.

Next stepUse the hydraulic gradient with Darcy's Law (Q = K i A) to estimate seepage flow rate through soil, or with Darcy-Weisbach to size pipes for allowable head loss.

 = Powered by OnlyCalculators