Geology 127 (Hydrogeology)

California State University, Sacramento

Week 14: Geochemistry of natural waters


Upon completion of this unit students should be able to:

  • Identify the major elements or compounds that are found in groundwater.
  • List common sources and typical concentrations of major elements in ground water.
  • Identify common sources of major element/compound pollution.
  • Convert concentrations to equivalents per million.

Reading Assignments:

Lecture 18: Fetter, pp. 373-382, 385-389


For a quick review of some basic chemistry you may also want to read Fetter, pp. 346-362.


City of Sacramento Water quality report (2005):

Lecture notes:

Lecture 18

Homework Assignment:

Homework Assignment: Aquifer analysis

Topic: Geochemistry of natural waters, Piper trilinear diagrams

Assignment: Class handout.  Fill in the blanks for the five wells that have information missing.  Calculate the equivalents per million (EPM) and % for each ion.  Show your calculations for each well on a separate page.  Plot each unknown water on the blank Piper Trilinear diagram.

Due date: TBA


  • 60 points: Show your work on a separate page, and fill in the chart with EPM and % values for cations and anions in each of the five wells.

  • 40 points: Plot and label the five wells on the blank Piper trilinear diagram.

Homework solution (Piper diagram):


Link to homework solution