scematic view of aquifer from From: https://water.usgs.gov/edu/earthgwaquifer.html

Unit 14

Groundwater and its roles in the regional water cycle

This unit cover the role of ground water in hydrometeorology with respect to storing of water in the ground, ground water flow, as well as the regional water balance.

Schematic view of an aquifer confined by permafrost. Cracks or boreholes may cause an artesian well. From: https://highlatitudestyle.com/permafrost-artesian-wells-tundra-ootd/

Goals

The goal of this unit is to identify and discuss the role of   groundwater in the hydrological cycle in the lithosphere.

After successful completion of this unit students will be able to

  1. Explain the types of aquifers, unconfined and confined aquifers, and aquitards
  2. Quantify groundwater in terms of soil properties
  3. Discuss the storage, and transmission properties of different aquifers including residence and response times
  4. Explain the role of topography, geology, permafrost and climate for groundwater
ground water table and wells
The concept of “hydraulic head” or “head” at a point in an aquifer. From: USGS (2018)

Students’ tasks

  1. Read Dingman’s Chapter Chapter 9. to 9.2.5 (included)
  2. Watch this video

  3. Fill out the questionnaire prior to Thursday 2359 Alaska time
  4. Solve the tasks assigned at your class level in this Unit 14 Applications sheet. You will need this unit 14 excel spread sheet  for your assignment.

Complimentary material

This webpage has definitions of groundwater related terms and explanations of relevant processes.

Data resources

Data of wells up to the current year of the  High Plains Aquifer Groundwater Network

FAQ

Q: What is the differences between a confined and not confined aquifer?

A: Take a close look at this schematic view to see the difference. A confined aquifer has a confining, impermeable layer (e.g. a permafrost layer) below and above.

confined vs. non-confined aquifer From: From: https://water.usgs.gov/edu/earthgwaquifer.html
Schematic view of confined and non-confined aquifers. From: From: https://water.usgs.gov/edu/earthgwaquifer.html

Q: There are so many new terms. A schematic view to memorize them would be helpful.

Schematic view illustrating various ground water relevant terms. From: From: https://slideplayer.com/slide/4142808/

Q: Why do confined and unconfined aquifers react differently to pumping?

A: In unconfined aquifers, pumping dewaters saturated space and takes notable amounts of water from storage per unit volume of ground material in the depression cone . In confined aquifers, the entire layer of the aquifer keeps being saturated during pumping. While the pumping decreases the water head and   water pressure in the of depression cone . The decrease yields the groundwater to expand which compressed the soil matrix of the aquifer. The amount of water taken from the storage per unit volume of ground material in the depression cone is much smaller than for an unconfined aquifer. Consequently,   the storage coefficients differ by orders of magnitude.

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