Plotting Concentration-Flow Relationship Graphs
Plots of pollutant concentration versus flow are easy to make, requiring simply the pollutant concentrations and their associated flows for the samples collected within the period of interest. This information may be copied from the RiverData files into new Excel Worksheets prior to using the Excel Chart Wizard for making the plots.
Alternatively, you may use the Concentration versus Flow Plots worksheet of the AnalysisTemplatev3 program to select the river, parameter and inclusive dates. It will make the graph and create a data sheet with the selected data. It will also transfer the graph and data to a new Excel workbook for your subsequent use.
Caution in interpretation of concentration-flow
graphs: The points on these plots represent individual samples. Some samples represent one full day (primarily low flow samples), while other samples represent one third of a day (primarily high flow samples). Thus the distribution of points on the graph does not reflect the frequency of occurrence of conditions in the stream.
Water Quality Laboratory, Heidelberg College