How to link a 1D model to a 2D model

Why link these two pieces of software?

Linking 1D and 2D models in Flood Modeller gives you get the best of both worlds in one single model. 1D models are good for defining flow direction and modelling the channel cross-section, whilst 2D models are good for modelling the floodplain and representing more complex flow paths and velocities. 1D-2D linked models tend to be the default choice in many fluvial modelling situations, with the further advantage that they may be able to reuse previous 1D models. 1D modelling components can also be used to represent sub-surface drainage systems.

Which software is linked?

In this situation, Flood Modeller’s 1D and 2D Solvers are linked.

Types of links

There are three types of link lines that can be defined in your model. Each type exchanges different parameters between your 1D and 2D models. The available link types are:

How can this be done?

Details about creating Link Lines can be found in the section How Do I Create a 1D-2D Model Link Lines Shapefile? The following text shows the main steps to set up a 1D-2D Model linked simulation.

  1. Using the 1D-2D Link Line Generator

    You need to then work through this window selecting your required settings. The tool requires the following to be defined:
  2. Using the 2D Simulation window

    If creating a new model: open a new 2D Simulation window eg for a new model by right-clicking on Simulations in Project Panel ("New Project" Panel) > New 2D Simulation > Specify the name of the file and location > Save >2D Simulation window opens > Linked Models Tab > Tick Add Linked Model. If loading an existing 2D Model, right-click on Simulations in Project Panel ("New Project" Panel) > Add Item >Browse to the location of your 2D Model file and select  the file (.xml file) > Click Open >  Specify if you would like to add 2D model data to map (if you do decide to load it, note that it may take a bit of time depending on how large your ground grid is and how many files your 2D Simulation Project XML file contains) > Double- Click on the 2D Simulation project in the Project Panel ("New Project" under Simulations)>2D Simulation window opens > Linked Models Tab > Tick Add Linked Model.

    By default your 2D model will not have 1D model linking activated. This functionality is accessed by clicking to put a tick in the Add Linked Model on the Linked Models Tab. The 1D settings will then be activated, which should be populated as follows:
    1. Select your 1D event file (.ief) or type/paste filename (and full path) into the space provided.
    2. Provide a filename for Flood Modeller to write mass balance information for the 1D element of your model. Flood Modeller will provide a default name for this based on your 1D and 2D simulation names.
    3. Provide the output frequency for your 1D mass balance data (in seconds).
    4. Input your weir settings – weir discharge coefficient and weir modular limit. These are only used for weir type links.
    5. Add your link line shapefile (or multiple files) to your model by adding file references to the provided table. Use the + and – buttons to add or remove link line shapefiles in the table.
    6. You can also set individual weir parameters for each file (that override global values). These parameters are only used with links defined as weir types.
    7. Save the changes to your 2D SImulation Porject XML file by clicking on Save button on the 2D Simulation window.


Useful Link

Which link type should I choose to connect my 1D and 2D models?