Stiff Diagram - Chart

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Stiff Diagram - Chart

Stiff diagrams are graphical presentations of the cation and anion content of water presented in milliequivalents per liter. More information on the application of Stiff diagrams can be found in the USGS Water Supply Paper 2254, Study and Interpretation of the Chemical Characteristics of Water available at


50131-stiff_diagram 50131-stiff_diagram_mean


By convention, cations are plotted on the left side of the Stiff diagram and anions on the right. Equivalent weight values are required to be populated in the database prior to plotting this data. For more information, see the Equivalent Weight page.


Stiff diagrams may be generated as either georeferenced plots (small diagrams with a leader to the well location) or as full page Stiff diagrams. In the full page Stiff diagram plot, the diagrams are lined up vertically along the centerline of the page. To create a full page Stiff diagram:


1.Select Window> New> Stiff Diagrams from a plan view, or, on the Tasks Pane, select Create Window and then select Stiff Diagram. A new view window is generated and the Stiff Diagram dialog box opens.

2.Modify the properties of the Stiff diagram plot on the Query tab, Select Ions tab, Options tab, Labels tab, EQuIS Query tab and Delta tab as desired.

3.Click the OK button to save changes.


For EQuIS EnviroInsite clients, if the diagrams are not displaying as expected, check to see if DT_FACILITY.ELEV_UNIT is populated. If it is not, consider populating this information. Although it is not a required field for this report, it is recommended.


Query Tab




Select Ions Tab


The anions and cations to be plotted in the Stiff diagram are selected on the Select Ions tab of the Stiff Diagram dialog box. Each line on the Stiff diagram can represent a single ion or the sum of two ions. Leave the second ion blank to plot a single ion or leave both ions blank to not plot a particular line.




Options Tab




Labels Tab




Delta Tab