What is the Difference Between Aquifer and Artesian Aquifer

The main difference between aquifer and the artesian aquifer is that an aquifer is an underground layer of water-bearing permeable rock, rock fractures, or unconsolidated materials such as gravel, sand, or silt, whereas an artesian aquifer is a confined aquifer that contains groundwater under positive pressure.

Both aquifer and artesian aquifer refer to a body of permeable rock, containing or transmitting underground water.

Key Areas Covered

1. What is an Aquifer
   • Definition, Characteristics, Importance
2. What is an Artesian Aquifer
   • Definition, Characteristics, Importance
3. Similarities Between Aquifer and Artesian Aquifer
   • Outline of Common Features
4. Difference Between Aquifer and Artesian Aquifer
   • Comparison of Key Differences

Key Terms

Aquifer, Artesian Aquifer, Unconfined Aquifers

What is an Aquifer

An aquifer is an underground layer of water-bearing permeable rock, rock fractures, or unconsolidated materials like gravel, sand, or silt. Water wells can extract groundwater from aquifers. Moreover, aquifers have greatly variable characteristics. In addition, the study of water flow in aquifers and the characterization of aquifers is called hydrogeology. In hydrogeology, an aquitard is a bed of low permeability along an aquifer. Aquiclude or aquifuge is a solid, impermeable area, which underlays or overlays an aquifer. Furthermore, the pressure of the aquifuge creates a confined aquifer.

Figure 1: Aquifer

One classification of aquifers is confined and unconfined aquifers. Unconfined aquifers are sometimes called water tables or phreatic aquifers due to their upper boundary being the water table or phreatic surface. Generally, the shallowest aquifer at a given location is unconfined. That means an aquifer does not have a confining layer (an aquitard or aquiclude) between it and the surface.  

What is an Artesian Aquifer

An artesian aquifer is a confined aquifer that contains groundwater under positive pressure. In general, an artesian aquifer contains trapped water, surrounded by layers of impermeable rock or clay; this applies positive pressure to the water contained within the aquifer. A well drilled into the artesian layer is called an artesian well. Moreover, a flowing artesian well contains the water that reached the ground surface by the natural pressure of the aquifer.

Figure 2: Artesian Well

Moreover, fossil water aquifers are also artesian aquifers when they have sufficient pressure from surrounding rocks. Therefore, the main feature of the artesian aquifer is that it is a confined aquifer.

Similarities Between Aquifer and Artesian Aquifer

• Aquifer and artesian aquifers are two types of aquifers that contain trapped ground water.
• Moreover, water wells contain water from aquifers.

Difference Between Aquifer and Artesian Aquifer

Definition

Aquifer refers to an underground layer of water-bearing permeable rock, rock fractures, or unconsolidated materials such as gravel, sand, or silt, while artesian aquifer refers to a confined aquifer containing groundwater under positive pressure.

Confining Layer

Aquifers can be either confined or unconfined while artesian aquifers are confined and contain a confining layer between the aquifer.

Ground Water Pressure

Aquifers contain groundwater with natural pressure while artesian aquifers have positive pressure.

Rocks

Moreover, aquifers contain water-bearing permeable rock, rock fractures, or unconsolidated materials while artesian aquifers contain impermeable rocks and clay.

Hydraulic Conductivity

Aquifers have high hydraulic conductivity while artesian aquifers contain low hydraulic conductivity.

Conclusion

In brief, an aquifer is an underground layer of water-bearing permeable rock, rock fractures, or unconsolidated materials. Generally, there are two types of aquifers according to the pressure of underground water: confined aquifers and unconfined aquifers. Furthermore, confined aquifers contain a confined layer, impermeable rocks, and clay and this applies positive pressure on the underground water. In addition, artesian aquifers are confined aquifers. Unconfined aquifers do not have confining layers of rocks and therefore, underground water is under natural pressure. Therefore, the main difference between the aquifer and artesian aquifer is the pressure on underground water.

References:

1. Aquifers and groundwater completed. Aquifers and Groundwater | U.S. Geological Survey. (n.d.). Retrieved September 9, 2022.
2. Artesian Water and Artesian Wells completed. Artesian Water and Artesian Wells | U.S. Geological Survey. (n.d.). Retrieved September 9, 2022.

Image Courtesy:

1. “Aquifer en ” By Hans Hillewaert – Own Work (Public Domain) via Commons Wikimedia
2. “Artesian well Virttaa ” By MattiPaavola – Own Work (Cc By-SA 3.0) via Commons Wikimedia