# Hydraulic conductivity (Constant-head method)

## Description

Hydraulic conductivity is a property of vascular plants, soils and rocks, that describes the ease with which a fluid (usually water) can move through pore spaces or fractures. It depends on the intrinsic permeability of the material and on the degree of saturation, and on the density and viscosity of the fluid.

The constant-head method is a laboratory method to determine the hydraulic conductivity of a soil and is typically used on granular soil. This procedure allows water to move through the soil under a steady state head condition while the quantity (volume) of water flowing through the soil specimen is measured over a period of time.

The hydraulic contuctivity can be calculated by the quantity of water measured, the length of the specimen, the cross-sectional area of the specimen, the time required for the quantity of water to be discharged, and the preasure head.

## Variables

K | Hydraulic conductivity (cm/sec) |

Q | Water discharge (cm^{3}) |

L | Length of speciment (cm) |

A | Area of speciment (cm^{2}) |

h | Preasure head (Height differnece) (cm) |

t | Time required for the quantity of water to be discharged (sec) |