Artesian water

Artesian water refers to groundwater that is confined under pressure between layers of impermeable rock or clay, which applies a significant force on the water. When tapped by a well, the internal pressure might be sufficient to push the water up the borehole without the need for pumping. This phenomenon is named after the former province of Artois in France, where the first artesian well was drilled by Carthusian monks in 1126.

Characteristics

Artesian water is distinguished by its method of reaching the surface and its natural filtration process. As the water travels through porous rock formations, such as sandstone or limestone, it is naturally filtered. This process can contribute to the purity of the water, although the water may still contain dissolved minerals picked up during its journey. The pressure that causes the water to flow upwards is due to the weight of the water in the areas where the aquifer is replenished, often in hills or mountains.

Formation

The formation of an artesian aquifer requires a specific geological condition known as a confined aquifer. This occurs when a water-bearing permeable layer of rock, called an aquifer, is trapped between two impermeable layers. Rainwater or snowmelt infiltrates the ground in recharge areas and travels down through the aquifer until it reaches these impermeable layers. The water then moves laterally, confined under pressure. If a well is drilled from the surface down to the pressurized aquifer, the internal pressure might be enough to force the water up the well and to the surface without pumping.

Benefits and Uses

Artesian water is prized for several reasons. Its natural filtration and the minerals it acquires during its journey can make it desirable for drinking and bottling. Additionally, the pressure that drives the water to the surface can reduce the need for mechanical pumps, saving energy and maintenance costs. Artesian wells can be a critical water source for irrigation in agriculture, especially in arid regions where surface water is scarce.

Environmental Considerations

While artesian wells can be an efficient way to access groundwater, their use must be carefully managed to prevent depletion and the potential for contamination. Over-extraction can lower the pressure in the aquifer, leading to a decrease in water quality and the need for pumping. It can also cause subsidence, where the ground above the aquifer collapses due to the removal of water.

Regulation and Management

The sustainable management of artesian water resources requires regulation to prevent overuse and contamination. Many regions have implemented policies and guidelines for the drilling and operation of artesian wells. These regulations often include permits, regular monitoring, and restrictions on the amount of water that can be extracted.

See Also

• Aquifer
• Groundwater
• Hydrogeology
• Water well
• Water purification