The height of a column of freshwater that exerts pressure at a given depth. Some authors use the term synonymously with hydrostatic pressure.

In hydrologic terms, a measure of pressure at a given point in a liquid in terms of the vertical height of a column of the same liquid which would produce the same pressure

Indicates the pressure of water needed to penetrate a fabric usually noted in mm. It is used to define how waterproof a fabric is. For example a lightweight waterproof coat designed for use in showers will have a low (typically 1200mm) hydrostatic head. Whereas the ground sheet of a tent where the pressure of you walking/ sitting in it could force [..]

The amount of water pressure a fabric can withstand before it leaks. Expressed as the height of a theoretical column of water required to force water through the fabric. Values above 1'500mm are considered waterproof, and can be as high as 10'000mm for the leading waterproof fabrics like GORE-TEX and eVent. The higher the number the more [..]

A method to measure water resistance or waterproofing. A tube of 1 inch diameter is placed over the material, which is clamped to the end of the tube. The tube is then gradually filled with water. The height that the water gets up to before the material leaks, in millimetres, is the waterproof rating. A material cannot be deemed as waterproof if it [..]

The measure of a fabrics waterproof qualities. Measured in mm, it is the height at which a column of water has to reach before a fabric starts to leak.

A fabrics resistance to water pressure equivalent to a column height of water (eg 25,000mm) Used to test the waterproofness of materials used in tents,  jackets and outer trousers. Other factors such as wind, contact with vegetation, pressure of a rucksack on the back etc. can all increase the pressure and thus force water through.

A measure of pressure at a given point in a liquid in terms of the vertical height of a column of the same liquid which would produce the same pressure.

In hydrologic terms, a measure of pressure at a given point in a liquid in terms of the vertical height of a column of the same liquid which would produce the same pressure

a measure of pressure at a given point in a liquid in terms of the vertical height of a column of the same liquid which would produce the same pressure.

The height of a column of liquid. The difference in height between two points in a body of liquid.

The distance a volume of water has to fall in order to generate power.

The height of a vertical column of water.

In hydrologic terms, a measure of pressure at a given point in a liquid in terms of the vertical height of a column of the same liquid which would produce the same pressure