What is a Durov Diagram?
A Durov diagram, or plot, is a composite plot consisting of 2 ternary diagrams used by hydrogeologists to visualize and compare the chemical composition of multiple water samples. The square plot in between the two ternary diagrams is a projection of the cation and anion ternary diagrams. Samples that are grouped closely in the Durov projection square are assumed to have similar compositions of anions and cations.
One can also use an Extended Durov diagram which contains a pH plot at the bottom and a TDS (Total Dissolved Solids) plot to the right to make further geochemical comparisons among samples.
Durov diagram comparing multiple monitoring well water samples created in Grapher
How to Create a Durov Diagram:
- Click Home | New Graph | Ternary and select your desired plot type from Durov, Class Scatter Durov, Extended Durov, and Extended Class Scatter Durov.
- In the Open Worksheet dialog, select your data file and click Open. The Durov plot is created with the data columns assigned in the following order: cation X, cation Z, cation Y, anion X, anion Z, and anion Y. If creating an extended Durov the following data columns can also be included: pH, TDS, and class.
Once the plot is created the data columns being plotted as the X,Y,Z, or class variable can be adjusted in the Plot tab of the Property Manager after clicking on the Cation or Anion Plot in the Object Manager.
For additional information on customizing a Durov plot in Grapher watch the video below.
Why is a Durov Diagram Used?
By clustering water samples of similar chemical composition hydrogeologists can reveal relationships and properties for entire sample groups. Grouped samples can then be sorted into hydrochemical facies. Facies provide insight into the geochemical processes occurring within an aquifer, such as origin, mineral dissolution, ion exchange, and mixing between different types of groundwater.
Knowledge of these processes help track changes in the groundwater chemistry over time. Identifying potential sources of contamination and evaluating the effectiveness of remediation efforts. Ultimately, guiding stakeholder decisions related to water resource management, land use planning, and environmental protection.
The sample data file contains the recorded anion and cation concentrations in mg/l (or ppm) in columns B, C, D, E, I, J, K, and L. These columns and the ID in column A can be changed to any data desired. In addition, the values in the pH column can be entered by the user.
Once the data is input, open the GRF file in Grapher. The graph is automatically populated with the data.
Updated May 2023