Hydraulic Conductivity Calculator
Calculate soil or porous media conductivity from permeameter test data.
How to Use This Calculator
Collect test data
Measure steady flow rate Q, specimen length L, cross-sectional area A, and head difference Δh.
Use SI units
Enter values in m³/s, m, and m² to get K in m/s.
Calculate K
K is a material property indicating ease of flow through the porous medium.
Formula
K = (Q · L) / (A · Δh)
Where: Q = discharge (m³/s), L = specimen length (m), A = cross-sectional area (m²), Δh = head difference (m).
Example: Q = 1e-6 m³/s, L = 0.1 m, A = 5e-4 m², Δh = 0.05 m → K = (1e-6×0.1)/(5e-4×0.05) = 0.004 m/s.
About Hydraulic Conductivity
Hydraulic conductivity characterizes how easily fluid flows through porous materials like soils. It varies widely by material and saturation.
- Sands and gravels: high K (10⁻³–10⁻¹ m/s).
- Silts: moderate K (10⁻⁶–10⁻⁴ m/s).
- Clays: low K (≤10⁻⁹ m/s).
Frequently Asked Questions
What if my test is falling-head?
This page uses the constant-head formula. Falling-head uses a logarithmic relation; a separate calculator is recommended.
Units support?
Use consistent SI inputs to obtain K in m/s. Convert as needed (e.g., cm/s).
Saturation effects?
K depends on saturation, temperature, and soil structure; report test conditions.