Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Hydraulic gradient, abbreviated i, a dimensionless number, is the change in height (pressure) to length between any two points.

### Hydraulic Gradient Formula

$$\large{ i = \frac { h_1 \;-\; h_2} { l} }$$

Where:

$$\large{ i }$$ = hydraulic gradient

$$\large{ l }$$ = length of column

$$\large{ h_1 }$$ = pressure head at point 1

$$\large{ h_2 }$$ = pressure head at point 2

Solve for:

$$\large{ h_1 = i l \;+\; h_2 }$$

$$\large{ h_2 = h_1 \;-\; i l }$$

$$\large{ l = \frac { h_1 \;-\; h_2} { i} }$$