Department of Earth Science |Northeastern Illinois University

PRINCIPLES OF HYDROGEOLOGY
ESCI 337
Spring, 2004

Daily Objectives #18 (March 18, 2004)                                             Dr. Sanders

By the end of today's class, you should be able to do the following:

v  Explain the following to a colleague who missed class last time:
               
......... 1.
 datum 10. water table (relate it to hydraulic head!)

2.
 piezometer 11. gaining stream

3.
 total hydraulic head
 12. losing stream

4.
 elevation head 13. The relationship between flow lines and impermeable boundaries is ___________________________________.

5.
 pressure head 14. The relationship between flow lines and constant head boundaries is ___________________________________.

6.
 flow lines 15. The relationship between flow lines and the water table is ____________________________________.

7. equipotential lines 16. The geometric shape formed by two adjacent flow lines and two adjacent equipotential lines is roughly _______________________  or _________________________.

8. no-flow boundary 17. Changes in the spacing of equipotential lines or flow lines, or changes in the sizes of "squares",
should be  ____________________________.

9. constant head boundary 18. Water flows from higher _______________________ to lower _________________________.

v  Using your own quantitatively accurate flow net showing flow to a gaining stream in an unconfined aquifer, bounded at the bottom by an aquitard, draw at least a dozen piezometers, showing what the water level would be in each.   Trace your drawing, showing ground level, vertical scale, datum, stream surface, aquitard, and piezometers/water levels--but not the flow lines, water table, or equipotential lines!
 
v  Using someone else's sketch of water levels in piezometers (I will assign this part), draw a quantitatively accurate flow net, including flow lines, equipotential lines, and water table.

v  Draw a quantitatively accurate flow net for flow beneath the dam on the handout provided.  Be sure to label equipotential lines with their value.  For simplicity's sake, let's all use the same datum:  the flat bottom of the main portion of the dam.




v  Answer the following questions about the dam flow net:

  o  If the sediments have a hydraulic conductivity of 0.28 m/day, and the dam is 200 m long going back into the page, calculate the flow rate of water under the dam.  (Give your answer in units of cubic meters/day.)

  o  At Point A, what is the total hydraulic head?  Elevation head?  Pressure head?

v  Describe the use of the FLOWNET software included with your textbook.

Department of Earth Science | Northeastern Illinois University

© 2004 Laura L. Sanders.  Last updated March 18, 2004.