Artesian Wells and Confined Aquifers

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What primarily causes the rises and falls of water in artesian wells?

Changes in well depth

Changes in water table elevation

Changes in storage volume

Changes in pressure (correct)

What does the piezometric surface of a confined aquifer coincide with?

Storage volume of the water

Hydrostatic pressure level of the water (correct)

Well depth

Water table elevation

How is a confined aquifer defined operationally?

By determining water table elevation

By monitoring well depth

By measuring storage volume

By drilling (correct)

When does a flowing well result in a confined aquifer?

When the piezometric surface lies above the ground surface Signup and view all the answers

What happens to a confined aquifer when the piezometric surface falls below the confining bed?

It becomes an unconfined aquifer Signup and view all the answers

What defines the elevation of the piezometric surface in a well penetrating a confined aquifer?

Water level in the well Signup and view all the answers

In a confined aquifer, what causes flow according to the text?

Difference in hydraulic head causing a gradient Signup and view all the answers

What condition is necessary for groundwater flow in an unconfined aquifer?

Difference in groundwater elevation Signup and view all the answers

Where does the water rise to in a confined aquifer according to the text?

Piezometric surface Signup and view all the answers

What is the role of the impermeable layer in a confined aquifer?

Prevents water from flowing out the top Signup and view all the answers

In which type of aquifer does the hydraulic head need to create a gradient for flow?

Confined aquifer with equal hydraulic head Signup and view all the answers

What causes groundwater flow in an unconfined aquifer under flow conditions?

Difference in water table elevation Signup and view all the answers

What is the main reason water in a well penetrating an artesian aquifer may rise above the land surface?

The presence of a confining layer above and below the aquifer Signup and view all the answers

What causes the water level or piezometric head in a confined aquifer to be above the top of the aquifer?

The presence of alternating layers of low and high-permeability units Signup and view all the answers

What creates an additional component of pressure head in confined aquifers that causes water in a well to rise above the point of saturation?

The difference in elevation between the recharge area and the completion point of the well Signup and view all the answers

Which term refers to layers that overlay the low-permeability units in a confined aquifer?

Confining layers Signup and view all the answers

In a confined aquifer, what is generally true about the water pressure compared to atmospheric pressure?

It is higher than atmospheric pressure Signup and view all the answers

What is the term used for wells tapping a confined aquifer where water rises above the land surface without pumping?

Free-flowing wells Signup and view all the answers