• 12 parts
  • Checked October 2026

Parts of an Aquifer

A hillside cut open to show the water underground.

Parts of an Aquifer

Name Date

Tap any part to read, rename or leave it out

1 2 3 4 5 6 7 8 9 10 11 12
More options

Write the name of each numbered part.Answer key

  1. Unsaturated zone
  2. Water table
  3. Unconfined aquifer
  4. Confining layer
  5. Confined aquifer
  6. Well
  7. Recharge
  8. Spring
  9. Stream
  10. Artesian well
  11. Flowing artesian well
  12. Potentiometric surface

Drawn for this site on 2026-10-02 from plain geometry. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Next: a watershed, from divide to outlet

All 12 parts on the diagram

Show the list

Start here: main parts 6

  1. Unsaturated zone The ground above the water table. Its gaps hold air as well as some water.
  2. Water table The top of the saturated ground. Below it every gap in the rock is filled with water.
  3. Unconfined aquifer An aquifer with no confining layer above it. Its top is the water table, and it is the upper part of the saturated zone.
  4. Confining layer A layer of poorly permeable rock, such as clay or shale. It holds the water below it under pressure.
  5. Confined aquifer An aquifer with a confining layer above and below it. Its water is under pressure.
  6. Well A hole drilled into an aquifer to draw water out. In this one the water stands at the water table.

Wells, springs and recharge 6

  1. Recharge Water added to an aquifer from the surface. Rain soaks in where the lower aquifer reaches the surface.
  2. Spring A place where groundwater flows naturally out onto the land surface.
  3. Stream Flowing surface water in the valley. Groundwater leaving the aquifer seeps into it.
  4. Artesian well A well that taps a confined aquifer. Pressure makes the water rise above the top of the aquifer.
  5. Flowing artesian well An artesian well whose water flows out at the surface. Pressure in the confined aquifer pushes it out.
  6. Potentiometric surface The level artesian water rises to in a cased well. Where it lies above the ground, a well flows.

How this list was compiled: Every name checked on 2026-10-02 in two independent sources. (1) US Geological Survey, Water Science School, Aquifers and Groundwater, https://www.usgs.gov/water-science-school/science/aquifers-and-groundwater , and Artesian Water and Artesian Wells, https://www.usgs.gov/water-science-school/science/artesian-water-and-artesian-wells : water table, unsaturated zone, zone of saturation, aquifer, wells and springs, recharge, seepage into streams, confined and unconfined aquifer, confining layer, artesian well, flowing artesian well, water table well, potentiometric surface (also piezometric). (2) National Park Service, Glossary of Geologic Terms, table at https://www.nps.gov/common/uploads/sortable_dataset/geology/DBD85DC6-CA83-CEE3-0786454132D79FCD/nri-GlossaryTable.csv : aquifer, unsaturated zone, saturated zone, water table, confined aquifer, confining bed, artesian well, potentiometric surface, recharge, spring. (3) Wikipedia, Aquifer, https://en.wikipedia.org/wiki/Aquifer , and Artesian well, https://en.wikipedia.org/wiki/Artesian_well : unconfined and confined aquifer, confining layer (aquitard), saturated and unsaturated zone, water table, wells, a gaining stream, artesian well, flowing artesian well. Licence: own work

The drawing: Drawn for this site on 2026-10-02 from plain geometry. The hillside is invented; nothing is traced or copied. Licence: own work

How it works

The parts of an aquifer on one slice through a hillside, from a ridge down to a stream. Start with the six main parts, then the wells, the spring and where the water comes from.

Read the full guide

Label the parts of the aquifer

Start at the top. The unsaturated zone lies between the land surface and the water table. Below the water table the ground is saturated, and that water-filled ground is the unconfined aquifer. Under it come a confining layer and the confined aquifer.

Wells, springs and recharge

Rain soaks in on the ridge and recharges the lower aquifer. The middle well stops in the unconfined aquifer, so its water stands at the water table. The two artesian wells reach the confined aquifer, and their water rises toward the dashed potentiometric surface. A spring flows where the water table meets the hillside.

  • Where the dashed line runs above the ground, an artesian well flows. Where it runs below the ground, the water stops partway up.

Questions and answers

What is the difference between a confined and an unconfined aquifer?

An unconfined aquifer has no confining layer above it, and its top is the water table. A confined aquifer lies between layers of poorly permeable rock, such as clay or shale, so its water is under pressure.

What is the difference between the saturated and the unsaturated zone?

In the saturated zone, below the water table, every gap in the rock is filled with water. The unsaturated zone above it still holds some water, but its gaps hold air too.

What is the water table?

The top of the saturated zone: the level below which the ground is full of water. In a well drilled into an unconfined aquifer, the water stands at the water table.

Why does water flow out of an artesian well?

Water in a confined aquifer is under pressure, so in a well it rises above the top of the aquifer. Where the pressure is high enough, the water flows out at the land surface without a pump.

More quizzes

Show 7 more

Browse Science Quizzes