Hydraulic conductivity converter
Convert how easily water moves through soil or rock between the units of hydrogeology, drainage and septic design.
That's about the same as fine sand.
What it means
How fast does water pass?
For water at about 20 °C. Ranges for each soil span a factor of 100 or more; the darcy unit applies to water at 20 °C.
Every unit
That conductivity in every unit
Learn
Three things worth knowing
-
1 cm/s ≈ 864 m/day
Multiply m/s by 86,400 for m/day, by 283,465 for ft/day.
-
Darcy’s fountains
Henry Darcy, engineer of Dijon’s public fountains, measured water flowing through sand columns in 1856.
-
Not permeability
Permeability (darcy, m²) is a property of the rock; hydraulic conductivity also depends on the fluid. The same rock conducts oil less than water.
Shortcuts
Popular conductivity conversions
Background
About hydraulic conductivity
Darcy’s law says water flows through soil at a rate proportional to the slope of the water table: the constant is the hydraulic conductivity K. Gravel lets water through at about 1 cm/s, clean sand at 10⁻⁵ m/s, clay a million times slower.
It is permeability adjusted for water’s density and viscosity, which is why it has units of speed.