How to specify a new 1D model simulation

This section explains how to prepare and execute a new simulation for your 1D model network. It will also demonstrate some options available to visualise your 1D model results.

  1. A 1D model simulation is defined in a simulation file. For 1D models this is a text file that has a file extension “.ief”. Flood Modeller provides an interface to define new ief files and edit existing ones. This interface is also used to start simulations from.
  2. To start a new simulation (with your 1D network defined and loaded in Flood Modeller) right click on the simulations section of the project view and select New 1D Simulation from the displayed menu. You will be prompted to provide a filename and save location for the new simulation file in a standard browser window.
  3. The multi-tabbed simulation definition window will then be displayed, as shown below:
  1. The network currently active in Flood Modeller, i.e. showing in the map and tables and highlighted in bold text in the project view, will be automatically entered into the simulation window (in the section entitled “1D data file”). The results folder specification should also be set to the same folder as the selected network file location. To perform a simple steady, direct 1D simulation (i.e. a calculation of normal flow conditions with no time steps) the following steps should be followed:
  1. The output produced from a steady state simulation is a standard set of static properties for each node in your network .These are in a text file format that can be accessed from the Flood Modeller interface by right-clicking on the simulation file and selecting the View Results option in the displayed menu. The data will then be displayed by utilising a compatible text editor. Furthermore these results data can also be utilised as an initial conditions file for an unsteady time stepping simulation. This type of simulation will produce time varying outputs, e.g. impacts of the rise and fall of a storm event input into your network. The process for setting up and running a time stepping simulation is as follows:

 The options are:

o   Network file – this will use the initial conditions data embedded in your 1D network file (dat file). These data are displayed below the Network table in the main interface. The values can be edited in this table. Alternatively, if you have already run a steady state simulation to create an initial conditions (zzs) file, you can import these data into your Network file (from the network table right-click menu > File sub-menu).

o   Initial Conditions file – this option will use a separate, external text file to define the initial conditions for your network. This must be a either a steady state output file (zzs) or a snapshot initial conditions file from a separate steady simulation (iic file – same format as a zzs file). If this option is selected you must specify the external file you wish to utilise; either by dragging a file from the Initial Conditions section of your Project panel or by using the browse button provided.

  1. You can further customise your 1D simulation by activating some of the advanced settings for 1D modelling. These are accessed from the simulation definition window. Click the View menu and select Tabs to reveal a list of the available model specification tabs that can be activated. Each of these contain a set of related advanced model settings. Click on one of these to display the associated advanced tab (the process has to be repeated to display multiple extra tabs). Available tabs are:

Details on the functionality offered within each of these tabs can be seen in the Technical Reference section of the user guide (Introduction to Technical Reference ).

Once you have activated a tab to define a simulation Flood Modeller will remember this configuration. Thus, the next time you access the simulation definition window the same tabs will be displayed by default.

  1. A time varying 1D simulation will generate default time series outputs at every model node for the following parameters:

In addition advanced options are available to produce selected additional output parameters.

Select a node on the map view or in the network table where you want to see an associated model output.

  1. Right click either on the map view or on the network table and select an output review option. These options are listed below. More details on these options you can find at the start of the page How to View 1D Model Results?
  1. The chart that results from the options you select is displayed in a new window, like shown at the page How to View 1D Model Results?

    This chart includes a right-click menu that provides options to:
  1. Further time series outputs can be extracted from your 1D results using the TabularCSV tool. This can be accessed from the Results tab of the main toolbar. The tool will extract user selected data from the binary format output from your 1D model and write these data to a comma separated text format (file extension csv). This can then be imported into other software for further analysis, e.g. MS Excel or similar spreadsheet tools.
  2. In addition to producing time series results from individual or groups of model nodes you can also post-process these data to produce flood maps and animated mapping sequences. These are useful for showing the full impact of flooding in models where water encroaches out of bank onto the surrounding floodplain. A separate how do I guide explains how you post-process your 1D model data to produce these outputs (How to Create a Flood Map from 1D Model Results).