**The Kozeny-Carman equation is one of the most widely accepted and used derivations of permeability as a function of the characteristics of the medium. This equation was originally proposed by Kozeny (1927) and was then modified by Carman (1937, 1956) to become the Kozeny-Carman equation. In essence, this equation will estimate the permeability of media based on a grain size distribution. This equation is given by:**

Where

ρ = density

g = acceleration due to gravity

μ = dynamic viscosity

n = porosity

d_{10} = 10% cumulative passing (geotechnical grain size distribution)

**Input**

*Groundwater temperature estimate**: * ** **^{o}C

*n (porosity)***: **

**Click here for information on porosity values**

*d*_{10 }(from a geotechnical plot; % passing)**: ** **m**

**Click here for information on d**_{10} and particle sizes

**Hydraulic Conductivity: ** **m/s**

**Example:**

**A soil matrix has a porosity of 0.30 and a d**_{10} value of 0.1 mm. The groundwater is 10^{o}C. Determine the hydraulic conductivity.

**The resulting hydraulic conductivity should be 0.000023 m/s.**

**What would be a common error in this example?**

**- forgetting to convert the d**_{10} value from mm to m. The input should be 0.0001 m.

** **