What type of pressure is associated with confined groundwater due to gravity?

The type of pressure associated with confined groundwater due to gravity is known as Artesian Pressure. This occurs in aquifers that are confined by impermeable layers, which means the water is under pressure and can rise above the level of the aquifer when tapped. The pressure is primarily the result of the weight of the water above it in the aquifer and is governed by the hydrostatic pressure laws, where pressure increases with depth due to the weight of the overlying water column.

When a well is drilled into a confined aquifer, if the pressure is sufficient, water will flow to the surface without the need for pumping—this is the hallmark of artesian wells. The term "artesian" specifically refers to this phenomenon where hydraulic pressure forces the water to rise above the static water level in the aquifer.

While hydraulic pressure and static pressure do play roles in water movement underground, they are broader terms that do not exclusively describe the phenomenon of confined groundwater under pressure. Aquifer pressure is not a standard term used in hydrogeology to define groundwater pressure specifically, unlike the clearly defined conditions that lead to artesian pressure.