Hydrostatic head
Hydropower terminology
title: "Hydrostatic head" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["hydrology"] description: "Hydropower terminology" topic_path: "science/earth-science" source: "https://en.wikipedia.org/wiki/Hydrostatic_head" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Hydropower terminology ::
::figure[src="https://upload.wikimedia.org/wikipedia/commons/5/57/Hydroelectric_dam.svg" caption="As shown in this drawing, the ''hydrostatic head'' is the vertical distance between the water level in the reservoir and the turbine that is turned by the flowing water."] ::
When generating hydropower, the head is the distance that a given water source has to fall before the point where power is generated. Ultimately the force responsible for hydropower is gravity, so a hydroelectricity plant with a tall/high head can produce more power than a similar plant with a short/low head. In short, for a given water flow, a larger head will be converted into greater kinetic energy. That energy is then harnessed by a water wheel or water turbine to create usable hydropower.
Fabrics
Hydrostatic head is also used as a measure of the waterproofing of a fabric, commonly in clothing and equipment used for outdoor recreation. It is measured as a length (typically millimetres), representing the maximum height of a vertical column of water that could be placed on top of the fabric before water started seeping through the weave. Thus a fabric with a hydrostatic head rating of mm could hold back a column of water five metres high, but no more.
Notes
References
- U.S. Bureau of Reclamation: Glossary (See “Head”)
- U.S. Minerals Management Service: Glossary (See “Hydraulic head”]
- Society of Petrophysicists & Well Log Analysts: Glossary (See “Hydraulic head”)
References
- Alternatively, again for a given water flow, a larger head could produce the same power with smaller equipment.
- "What is Hydrostatic Head? We explain".
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