RockWorks | Utilities | HydroChem | Piper Diagram
This program is used to read a listing of ion concentrations from the datasheet and create a Piper diagram for groundwater ion concentration analysis.
Below is a summary of all of the parts of a Piper diagram.
Piper diagrams consist of three parts: Two trilinear diagrams along the bottom and one diamond-shaped diagram in the middle.
The trilinear diagrams illustrate the relative concentrations of cations (left diagram) and anions (right diagram) in each sample. For the purposes of a Piper diagram, the cations are grouped into three major divisions: Sodium (Na+) plus Potassium (K+), Calcium (Ca++), and Magnesium (Mg++). The Anions are similarly grouped into three major categories: Bicarbonate (HCO3-) plus Carbonate (CO3--), Sulfate (SO4--), and Chloride (Cl-). Each sample will be represented by a point in each trilinear diagram; unique symbols may be selected for each sample and can be referenced in a symbol index at the top of the diagram. Symbols may be accompanied by labels if desired.
Concentrations entered in the source data file in units of milligrams per liter are converted to milli-equivalents per liter for display on the diagram. (See Conversion Factors.)
The diamond field is designed to show both anion and cation groups. For each sample, a line is projected from its point in the cation and anion trilinear diagrams into the upper region; where the lines intersect, the symbol is plotted. Circles may be plotted around each point to illustrate total dissolved solids ("TDS") for the sample. The total dissolved solid computation will include all components listed in the data file ("standard" ions and additional ions).
Menu Options
Step-by-Step Summary
Menu Options
- Input Columns: The prompts along the left side of the window tell RockWorks which columns in the input datasheet contain what data.
Click on an existing name to select a different name from the drop-down list.
- Sample ID: If you have sample numbers listed for your sites, choose the column where these are listed.
- Symbol: Choose the column that lists specific symbols for the individual samples.
- Na, K, Ca, Mg: Choose the columns that list these required cations. The measurements must be listed in ppm or mg/l units.
- Cl, HCO3, CO3, SO4: Choose the columns that list these required anions. The measurements must be listed in ppm or mg/l units.
- Cation A, B, C, D: If you are including any additional cations (see Additional Cations, below), choose their columns here.
- Anion A, B, C, D: If you are including any additional anions (see Additional Anions, below), choose their columns here.
- Additional Cations: In the middle pane of the program window, expand this heading to turn on up to 4 additional (non-standard) cations to be included in the Piper plot's TDS (total dissolved solids) computations, if activated. Click in each check-box to turn an ion on or off. Be sure that the ions are correctly identified in the input columns to the left.
- Conversion Factors: For each additional ion, you also need to declare a conversion factor to convert from ppm or mg/l to milli-equivalents. See Conversion Factors for help.
! This is important - RockWorks will not know this conversion factor automatically. You need to enter it manually.
- Additional Anions: Expand this heading to turn on up to 4 additional, non-standard, anions to be included in the Piper plot's TDS computations. Click in each check-box to turn an ion on or off. Be sure that the ions are correctly identified in the input columns to the left.
- Conversion Factors: For each additional ion, you also need to declare a conversion factor to convert from ppm or mg/l to milli-equivalents. See Conversion Factors for help.
! This is important - as above,RockWorks will not know this conversion factor automatically. You need to enter it manually.
- Titles: Expand this item to specify text, if any, for the main and secondary diagram titles. You may enter up to 60 characters for each title. Expand these items to select their color.
- Border: Insert a check-mark here if you want the diagram border to be plotted. Expand this item to choose the style and color.
- TDS Circles: TDS (Total Dissolved Solids) circles are plotted as rings around each point in the diamond portion of the Piper diagram, and represent the combined total of all of the cations and anions in parts per million (or mg/l) for that sample (standard and any additional ions).
- Scaler: If activated, you need to determine the scale at which the TDS circles will be plotted, using this setting. The number entered in this prompt will represent the number of ppm (or mg/l) units represented by the fixed-size Scale Bar which can be plotted to the left of the diagram, and the radius of the TDS circles.
Here's an example for which the total dissolved solids for this single sample is 1,000 ppm. The scaler is set to 2,000. The radius of the circle is half the length of the fixed-size scale bar.
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- Symbol Index: If activated, a small index listing sample ID's and their symbols will be included to the right of the Piper diagram. If your samples have unique symbols, this is a handy way to identify samples without having to include labels in the diagram itself.
- Major Dividers, Minor Dividers: Insert a check in either/both of these items to create a reference background grid for both the triangular plots and the diamond plot. Expand these items to select their spacing (in percent) and line style and color. The percentage interval you select for the Major Dividers will also determine the axis labeling interval.
- Axis Titles: Insert a check here to label the axes with the ions that they represent. You cannot change the text for these labels. Expand this item to select the title color.
- Axis Labels: Insert a check here to label the axis with the percentage intervals selected for the Major Dividers, above. Expand this item to select the label color.
- TDS Scalebar: If activated, the Total Dissolved Solids scalebar will be included with the diagram, at the scale declared under the TDS Scaler, above. Expand this item to select the scale bar color.
- Point Symbols: Insert a check here to have the symbols listed in the main datasheet plotted for each sample in the Piper diagram, using the color also listed in the datasheet. Expand this item to select the Size declared as percent of diagram width (default = 4.0).
- Point Labels: If activated, the sample's Point Symbols will be labeled with the sample ID. Like the symbols, above, you may click on the Size item to establish label size, in percent of diagram width. You can also choose label color.
Step-by-Step Summary
- Access the RockWorks Utilities program tab.
- Create a new datasheet and enter/import your hydrochemistry data into the datasheet.
Or, open one of the sample files and replace that data with your own. (In the Samples folder, an example file = "RockWorks17 Data\ Samples\Hydrochemistry_01.rwDat".)
- Select the HydroChem | Piper Diagram menu option.
- Enter the requested menu items, described above.
- Click the Process button to continue.
The program will read the ion concentration information from the Utilities datasheet, convert the ppm or mg/l measurements to milli-equivalents per liter based on the conversion factors, normalize the measurements to plot the anions and cations in the trilinear plots, and project the samples up into the diamond plot. If total dissolved solids circles were requested, they will be computed and drawn around the sample points in the upper diagram.
- You can adjust any of the diagram options along the left and click the Process button to regenerate the plot.
! Each time you click the Process button, the existing display will be replaced.
- View / save / manipulate / print / export the diagram in the RockPlot2D window.
Back to Hydrochemistry Menu Summary
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