Monday, April 21, 2014

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Medieval invention: Artesian wells and understanding water hydrology

A practical application of natural water recharging

by Ferdinand III

medieval buildersMotif of a Medieval Artesian well.

The Artesian well was invented in the early 12th century in France by Carthusian monks at Artois. The main idea of an Artesian well is to use natural water pressure and avoid pumping the water out of the earth. Some clever monks devised the usage of a thin iron rod, with hard cutting edges along its side. This rod would be inserted into a shaft which was drilled in the ground and repeatedly hit with a hammer. The idea was to have the rod make contact with the underground spring or water table and force the water back up the hole without the aid of a pump.

The key insight was to use the natural water pressure resident in an aquifer. Certain geographies have large amounts of water trapped in the earth, reasonably close to the surface [60-200 feet in depth] in the form of an aquifer, or a layer of soft rock which accumulates water from either natural water recharge, rain, or from nearby lake and river systems. The soft rock does not block the passage of this water into natural holding areas, located between impervious rock layers. If you sink a shaft into this aquifer basin and pressure drill, you can force the water back to the surface.

The benefits of artesian wells were and still are, many. Modern well systems in rural locations use the same premise of aquifer drilling as the Carthusian monks developed. Potable, clean water was thus made available to rural areas that might otherwise be water bereft. Artesian well water was used in industry during the medieval period, in brewing for example, and in providing clean, reliable water not contaminated by the rising population which used rivers and lakes for waste discharge.

The artesian well demonstrates skills and percipience. Understanding water pressure, aquifer location, the dynamics of water recharge and natural accumulation, show a society rather keen on understanding and using natural phenomena to their advantage. A very practical society one would say.