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29/03/2019 11:03:44

You might not have realised, but Flood Modeller includes tools to automate parts of the 1D network build process. These tools are designed to enable repetitive tasks to be performed automatically.

Not only can they greatly improve the speed of some of the more common model building and editing tasks, but also help ensure your 1D model is as free from error as possible. Common mistakes, for instance, due to a lack of concentration can thus be avoided.

The functions provided by these tools are:

  • Automatic interpolation (including replicates for conduits)
  • Automatic De-interpolation - reverses the above process
  • Intelligent model build to automatically add to a 1D network:
    • Single structures
    • Multiple structures and/or spills in parallel
    • Simple insert (copy channel section and insert structure between)
  • Link multiple sections to a reservoir via spills
  • Cross-section Flipper - Flip selected cross section data from left to right

This article shows you where to find these useful tools and how to use them.

Model Build Settings

The automation tools utilise a number of settings to define their behaviour. Therefore, you should review the appropriate settings prior to using the tools.

Settings for the interpolator and model builder options are set via the "Model build" tab of the 1D Options window. This is accessed from the “1D Options” button located in the Home tab in Flood Modeller interface. Note: You must have at least one 1D network loaded in your project to access this window (though the settings you specify here will then apply to all loaded networks).

Model Build Settings - Picture 1

 The options displayed here enable you to:

  • Turn on the intelligent build function – to automatically add 1D units required to fully define a structure, e.g. replicate upstream section, optional spill units and junctions
  • Specify interpolate cross-section spacing

These will be described in further detail in the relevant sections below.

Model Build menu

To access most of the model build and interpolate functions, right-click on the network table (right-hand panel) and select Model Build from the displayed menu (it’s located near the bottom of the menu options). The various functions appear in a sub-menu as follows:

Model Build menu

Interpolator tasks

Automatic interpolation tool

This enables you to refine the distance spacing between cross-sections without the need for extra surveyed sections. This can aid stability in, for example, steep channels or low flow scenarios. NB a direct method steady-state simulation of your network will give recommendations where extra interpolate sections are needed.

By using this tool to add the extra interpolate sections, you will ensure correct connectivity within the network and correctly entered chainages defining the separation between sections. The tool will also ensure that the original cumulative chainage is preserved for your network.

Before accessing this function, first select the required channel sections you wish to add interpolates between. Selection can be made on the map view or in the network table panel. You must have at least two valid sections selected (if only one selected then the auto-interpolate function will do nothing).

Automatic Interpolation tool - pic1


This functionality applies to RIVER sections, CES sections and all types of conduits. For RIVER, CES and CONDUIT SECTIONS the function will add INTERPOLATE sections; for other types of CONDUIT (geometric shapes) REPLICATE sections will be added (NB interpolate units are invalid with geometric conduit shapes).

After selection is made, right click on the network table and select Model Build > Auto-Interpolate. Multiple interpolate sections (or replicate sections for geometric conduits) will then be added to the active network. The tool calculates the minimum number of new interpolates required between each pair of selected sections to deliver equal separations less than the user-specified maximum distance spacing (as defined in 1D Options). For example; if two river sections were separated by 450m and the maximum distance spacing was set at 100m then the tool would add 5 new interpolates with a 90m separation between each one (if only 4 interpolates were added then the separation would be 112.5m, i.e. >100m).

Automatic Interpolation tool - pic2


The initial positioning of your new interpolates on the map view will likely not correspond to their defined equidistant separation. To correct this view, right-click on the map panel and select Refresh from the displayed menu.

Automatic Interpolation tool - pic3

The tool will automatically name all your new interpolate units using a basic naming convention (CH0001, CH0002, CH0003, etc.).

Once you are satisfied with your revised network remember to click the Save Network button (Home tab of main toolbar). This will save the new interpolates to the network and to the corresponding georeferencing file (gxy file).

De-interpolation tool

As its name suggests, this function may be used to remove interpolate and replicate units and reinstate the combined distance to next cross-section in the upstream-most unit.

Note: It is not a prerequisite that the units were inserted using the automatic interpolate tool.

This enables you to either undo a previous auto-interpolate operation, or to remove any extraneous sections which are no longer required.

To use this tool, first select the required channel sections in the network table or map view (at least two must be selected for the function to work). Right-click on the network and select Model Build > Auto De-Interpolate from the menu. The interpolates and/or replicates lying between your selected sections will be removed (the process usually takes a few seconds).

De-interpolation tool - pic1

Once you are satisfied with your revised network remember to click the Save Network button (Home tab of main toolbar). This will save the network and match this revised content in the corresponding georeferencing file (gxy file).

Build tasks

Intelligent model build

This function enables the modeller to perform selected common build functions, thus saving time and ensuring the correct model connectivity. Options within the intelligent build tool are:

  • Adding both a spill and a structure, in parallel, in a single operation.
  • Replicating the section to the downstream face of the structure and setting its distance to next section as zero.
  • If the structure is a bridge, replicating the section data into the bridge unit.
  • Adding multiple structures in parallel.

Adding structures into a model involves a number of processes; this functionality replicates these processes into one combined operation. For instance, one would need to copy the section, insert the structure between the two sections, possibly adding a spill bypass around (or over) the structure and linking all the units together. The intelligent insert tool performs all of this in a single automated operation:

  • It replicates the section and ensures the correct longitudinal chainage values are assigned.
  • For bridge units, the river cross-section data is replicated within the bridge unit.
  • You can choose to add a spill in parallel and also for multiple structures to be added (e.g. multiple-barrelled culverts, sluice complexes). When doing this the tool ensures the correct connectivity, e.g. junctions added upstream and downstream to link the parallel units. A pop-up window is displayed by the tool prompting you to select the required spill behaviour:

Intelligent Model Build - pic1

The default spill behaviour is to add a "high spill" in parallel - this adds a spill at an unrealistically high level (i.e. so it will not ever allow water to flow over it), but its purpose is to add the basic structure in readiness for you to edit accordingly.

Alternatively, you can choose to replicate the upstream cross-section data into the spill section. This is recommended if the structure is to be bypassed round the side; in this case, you should block out the middle section of the spill (i.e. that which represents the structure) to prevent water passing through this section of the spill.

Irrespective of the choices you make, it is recommended that you always review the spill data created by the intelligent insert tool, and amend as appropriate, before proceeding.

Note that the tool will not position the new units correctly on the map. Furthermore, the tool will use an automatic naming convention for any new units added to your network. A typical outcome from the tool is as follows:

Intelligent Model Build - pic2

If you want to change the automatic labels, then access the relevant node properties windows and click the Edit Labels button. Note some labels will appear in multiple units, e.g. spill upstream and downstream labels.

You will need to use the Move Nodes function (on the map right-click menu) to separate spills and junctions and position all new units as required. You may also see some new units get assigned an incorrect icon. Don’t worry about this as when you save your revised network or simply refresh the map view (on map right-click menu) the icons should all be refreshed and any display errors corrected, as shown in the example below:

Automatic Interpolation tool - pic4

Once you are satisfied with your revised network remember to click the Save Network button (Home tab of main toolbar). This will save the network and match this revised content in the corresponding georeferencing file (gxy file).

When adding a new structure in a 1D model, the intelligent insert is performed automatically if the relevant option is ticked. A tick box is provided in the Model Build Tab of the 1D Options Window to turn "intelligent insert" on/off (access 1D options from the Home Tab – note a 1D network has to be first loaded).

Link sections to reservoir

This enables multiple river sections to be simultaneously connected to the same existing reservoir unit, adding a spill unit in between and ensuring the correct connectivity.

This function speeds up the process whereby a reach containing many cross-sections is linked to a floodplain or other offline storage, represented by a reservoir unit.

To apply this (NB It is assumed that the reservoir is already present in the 1D model):

  1. Select all the river units required to be linked, either by highlighting on the map or in the network table.
  2. Right-click on the network table and select Model Build > Link to reservoir from displayed menu.
  3. A pop-up window is displayed. Select the name of the reservoir to which the sections are to be linked from the pull-down menu.Link sections to reservoir - pic1
  4. Note: The choice of Left or Right bank determines the elevations assigned to each end of the spill unit, either from the appropriate Left or Right bank marker location (if present), or the highest elevation left or right of the bed, within the River Section data.
  5. Remember to click the Save Network button to commit the changes to your network file.

The elevation data for the spills can be further refined, either manually or derived from a DEM using the Flood modeller spill generator tool (Map Tools tab of main toolbar or also accessible from Toolbox).

Cross-section Flipper

The convention for 1D cross-section data is to specify in the order from left to right when facing downstream.

If you receive survey data or model files with section data in the opposite order then this tool enables the data to quickly be reversed and thus conform to the required convention.

Although this has no effect on the hydraulic calculations, the ordering may be important for the following reasons:

  • Linking with other tools, e.g. Map view in Flood Modeller, Flood Modeller 2D or TUFLOW linked models, may rely on the data ordering being correct.
  • Any cross-referencing is correct, e.g. when georeferencing or extending cross sections to include flood plain.
  • Ensuring consistency throughout model
  • Improving clarity for subsequent users of the model.

To apply this function:

  1. Select the 1D units which you want to reverse in your model, either by highlighting on the map or in the network table.
  2. Right-click on the network table and select Model Build > Flip cross sections from the displayed menu
  3. The process should be automatic and should report how many sections have been affected once completed
  4. Remember to click the Save Network button to commit the changes to your network file.

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