Summative Assessment: Hydraulic Head and Aquifers

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As you've learned in Module 6.2, the driving forces for groundwater are a bit more interesting – and also more complicated – than those for streams or rivers. In particular, groundwater is not in communication with the atmosphere at the Earth’s surface, so groundwater may have considerable pressure energy in addition to that due to gravity. As you now know, the driving forces for groundwater flow are measured and reported in terms of hydraulic head, which is a proxy for the potential energy in the water. It is measured by wells, and defined simply as the level to which water rises. (In many ways this is analogous to temperature: we cannot measure the average energy of molecules directly, but we can measure temperature, which serves as a proxy. The more energy the molecules have, the more energetically and frequently they “bump” in to the thermometer tip, and the higher the mercury rises.)

In this activity, you will explore a series of examples to think more carefully about these driving forces, how they translate to the direction and rate of groundwater movement, and how they relate to mixing and contamination of aquifers.

Instructions

Download the worksheet linked below and follow the instructions provided.

Files to Download

The lab worksheet will be handed out in class. You can also download the worksheet here:

Download the worksheet

Submitting Your Answers

You will be working on this lab in class and handing it in at the end of the session.

Grading and Rubric

Rubric
Work Shown Possible Points

Question 1

  • correctly illustrate the elevation head and pressure head
  • correctly illustrate flow from right to left, horizontally within the tube, using an arrow

 

  • 10 points
  • 10 points

Question 2

  • correctly noting the values of hydraulic head at each point on the diagram
  • correctly noting the values of pressure and elevation head separately for each hydraulic head
  • correctly drawing arrow showing flow

 

  • 12 points
  • 12 points
  • 6 points

Question 3

  • correctly sketching the water table 
  • correctly drawing arrow showing flow 

 

  • 10 points
  • 10 points

Question 4

  • correctly labeling upper and lower aquifers
  • correctly sketching the water table and a flow arrow
  • correctly how flow is driven
  • answers will vary

 

  • 10 points
  • 10 points 
  • 5 points
  • 5 points