Enter the horizontal hydraulic conductivity, the horizontal hydraulic gradient, and the effective porosity into the calculator to determine the groundwater velocity.

Groundwater Velocity Formula

The following equation is used to calculate the Groundwater Velocity.

Vgw = K*L/n
  • Where Vgw is the groundwater velocity
  • K is the horizontal conductivity
  • L is the horizontal hydraulic gradient
  • n is the effective porosity

To calculate the ground water velocity, multiply the horizontal conductivity by the horizontal hydraulic gradient, then divide by the effective porosity.

What is a Groundwater Velocity?


Groundwater velocity measures the speed at which water runs over a section of ground, typically during a flood. The speed of the water depends on several factors, including the porosity of the soil.

How to Calculate Groundwater Velocity?

Example Problem:

The following example outlines the steps and information needed to calculate the Groundwater Velocity.

First, determine the horizontal conductivity. In this example, the horizontal conductivity is found to be 5.

Next, determine the horizontal hydraulic gradient. For this problem, the horizontal hydraulic gradient is found to be 3.

Next, determine the effective porosity. In this case, the effective porosity is measured to be 2.

Finally, calculate the Groundwater Velocity using the formula above:

Vgw = K*L/n

Vgw = 5*3/2

Vgw = 7.5