18 Questions
What primarily causes the rises and falls of water in artesian wells?
Changes in pressure
What does the piezometric surface of a confined aquifer coincide with?
Hydrostatic pressure level of the water
How is a confined aquifer defined operationally?
By drilling
When does a flowing well result in a confined aquifer?
When the piezometric surface lies above the ground surface
What happens to a confined aquifer when the piezometric surface falls below the confining bed?
It becomes an unconfined aquifer
What defines the elevation of the piezometric surface in a well penetrating a confined aquifer?
Water level in the well
In a confined aquifer, what causes flow according to the text?
Difference in hydraulic head causing a gradient
What condition is necessary for groundwater flow in an unconfined aquifer?
Difference in groundwater elevation
Where does the water rise to in a confined aquifer according to the text?
Piezometric surface
What is the role of the impermeable layer in a confined aquifer?
Prevents water from flowing out the top
In which type of aquifer does the hydraulic head need to create a gradient for flow?
Confined aquifer with equal hydraulic head
What causes groundwater flow in an unconfined aquifer under flow conditions?
Difference in water table elevation
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
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
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
Which term refers to layers that overlay the low-permeability units in a confined aquifer?
Confining layers
In a confined aquifer, what is generally true about the water pressure compared to atmospheric pressure?
It is higher than atmospheric pressure
What is the term used for wells tapping a confined aquifer where water rises above the land surface without pumping?
Free-flowing wells
Learn about the rise and fall of water in artesian wells, primarily due to changes in pressure rather than storage volume. Explore the concept of piezometric surface in confined aquifers and how it relates to water levels in wells.
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