Hydraulic Gradient Calculator
Determine the energy slope between two points in a flow system.
How to Use This Calculator
1
Measure heads
Determine water surface or piezometric heads at two points.
2
Measure distance
Use the along-flow distance L between the two points.
3
Compute i
i is dimensionless and represents energy grade line slope.
Formula
i = Δh / L
Where: Δh = head difference (m), L = separation distance (m).
Example: Δh = 1.2 m over L = 100 m → i = 0.012.
About Hydraulic Gradient
Hydraulic gradient drives seepage flow in soils and aquifers. It is central to Darcy's law: q = k i, where q is specific discharge and k is hydraulic conductivity.
Frequently Asked Questions
Is hydraulic gradient dimensionless?
Yes. It is a ratio of length to length (m/m).
What distance should I use?
Use the flow path distance, not straight-line if they differ significantly.