WMS:Hydrographs

A hydrograph can be computed from any of the supported hydrologic models. A hydrograph can also be defined/imported using the New command in the Hydrograph menu. This option allows you to copy a hydrograph from the clipboard, or open a text file using the text import wizard and define it for a selected basin or outlet node.

The hydrograph should be selected prior to bringing up the detention basin calculator.

Reading Hydrographs

Hydrographs can be read into WMS from a results files using the Open command in the Hydrographs menu. Hydrographs are generated for each basin and outlet point when running one of the hydrologic models. Two hydrographs may be generated for the outlet points, one representing the combination of "upstream" hydrographs, and one representing a hydrograph which has been routed to the next downstream outlet point.

If multiple storms or multiple ratios of a given storm are analyzed in the same run of HEC-1, then multiple hydrographs for each basin and outlet point will computed. If multiple storms have been defined using the JD card, the index numbers of hydrographs to be read must be specified. All indices or particular numbers can be specified. If multiple ratios of the same storm exist (defined on JR records), all ratios will be read. The display of a given ratio is controlled from within the Hydrologic Modeling tab in the Display Options dialog. Currently multi-plan storm hydrographs are not read.

Each storm index becomes a separate hydrograph set. Hydrograph sets are named by appending the index number to the file from which it is read. While it may be convenient to read all indices each time, it may produce an overwhelming number of hydrographs and make the display too cluttered for comparisons.

It is often useful to read a hydrograph not computed by HEC-1, or one of the other hydrologic models for calibrating purposes. This can be done by creating a hydrograph file using the WMS file format, but an easier method is to use the New command in the Hydrograph menu (or by right-clicking on a basin or outlet station from the Project Explorer) to either open a spreadsheet text file, or paste a copied hydrograph from a spreadsheet program using the Text Import Wizard. The basin or outlet where you wish to define the hydrograph (i.e. the point where you wish to compare a computed hydrograph with the measured hydrograph) should be selected prior to using this command.

New Hydrographs

Sometimes it is useful to create a new hydrograph, not computed by one of the WMS models, for calibration or further analysis. This can be done using the New command in the Hydrograph menu after selecting the basin/outlet where you wish to associate the new hydrograph. When selecting this command you can choose to import an existing text file or paste from the Windows clipboard a hydrograph that has previously been cut/copied from a spreadsheet or text file. In either case the data will be processed using the Text Import Wizard and a new hydrograph created for the selected basin/outlet.

The text file or copied data should include a column for time and a column for flow. A couple of limitations associated with creating a new hydrograph in this fashion are that the times must be in minutes and the time step must be constant. After copying from the clipboard, or opening the text file the data will be placed in the Text Import Wizard and you will be able to identify header rows, set the starting row, and map the columns to their respective data fields.

Related Topics

• Detention Basin Calculator
• Displaying Hydrographs