Read this article when you have a SOBEK 2 model and you want to convert it to SOBEK 3. If you want to import a DUFLOW model, see reference Jeuken (2014).

Preface

SOBEK 3 is refaced against SOBEK 2 in terms of modeling concept and features. This means that some features in SOBEK 2 are no longer supported and some objects are modelled in a different way.

The following table gives an overview about differences in the modelling concepts between SOBEK 2 and SOBEK 3:

SOBEK 2	SOBEK 3
Hydraulic structures in channel flow module and rainfall runoff module	Hydraulic structures in D-Flow 1D module only
Control of structures in channel flow module and RTC module	All control of structures in D-Real-Time Control module (D-RTC)
Rainfall-runoff module contains open water node	D-Rainfall Runoff (D-RR) has no open water node, it contains only rainfall-runoff processes.
Rational method in channel flow module (lateral station node) and rainfall-runoff module	No rational method in D-Flow 1D. The rational method is only available in D-Rainfall Runoff
Storage and lateral node available in channel flow module	D-Flow 1D does not contain a storage and lateral node (planned feature)

Approach

Import the SOBEK 2 model into SOBEK 3 and choose features

Procedure:

Start with the SOBEK 2 channel flow module.
- Modify the SOBEK 2 model in such a way that the corresponding SOBEK 3 model produces the same results, or that all differences in results can be explained.
- Finalize the 1D flow model by manual modifications.
Continue with the rainfall-runoff module.
Continue with the water quality module.

1D flow

Clean up the SOBEK 2 model

First clean up the SOBEK 2 model with the Cleanup Utility:

SOBEK User Community > [intermediate] How to migrate SOBEK 2 models to SOBEK 3 > SobekCleanUp.png

Import to SOBEK 3

Now create a SOBEK 2 model that can be imported in such a way that there is no difference between the SOBEK 2 model and the SOBEK 3 model with regards to the contents.

This is an iterative process:

Import your SOBEK 2 model with the help of the import feature in SOBEK 3.
Check the import log messages. Are there any features that are not supported, any values that are modified by the import tool?
Modify your SOBEK 2 model accordingly: delete features that are not supported in SOBEK 3.
Repeat the three steps above until there are no model differences between the SOBEK 3 model and the SOBEK 2 model.

To import the model, use the SOBEK 3 import tool:

SOBEK 3 import window. Choose "SOBEK Model (Flow 1D, RTC, RR, WAQ)". This window is accessible via File --> Import
Select case after opening CASELIST.CMT

Dependent from the choices you make, you receive an integrated model with the following sub-models:

water flow 1d
real-time control

The following list gives examples for modifications that might be necessary:

The rational method on lateral inflow is not supported, lateral inflow must be accounted for in a different way, for example with a set of time series.
Infeasible bottom levels for culverts must be changed.
Open water nodes are not imported into D-Flow 1D. They must be deleted in the SOBEK 2 model.
Structures in the rainfall-runoff module must be deleted.

The following warning messages do not require any modifications in the model, but can explain different model results:

The initial value 0 of PID controller <id> will not be used. The defined structure dimension is the initial value:
- In SOBEK 3 you can’t define an initial value of the PID, therefore the initial structure setting are used as initial value.
The initial value -5.37 of PID controller <id> will not be used. The defined structure dimension is the initial value
- In SOBEK 3 you can’t define an initial value of the PID, therefore the initial structure setting are used as initial value.
Case setting CrestlevelOpeningsHeight cannot be imported, model parameter setting not available.
Case setting StructureDynamicsFactor cannot be imported, model parameter setting not available.
Case setting Steady cannot be imported, model parameter setting not available.
Computational grid import: 1 grid points were skipped in branch '<id>' because there are structures defined at these locations.
- There is no longer a gridpoint on structures necessary.
Friction data of definition <id> of cross-section <id> has not been found. The main bed of branch <id> is used as roughness data.
- This warning is related to a network element that is no longer available in the model after it has been deleted by a user.
Friction BDFR <id> is linked to branch definition <id> without any tabulated, standard or river profiles; ignored.
Friction BDFR <id> is linked to branch that does not exist (id 0); ignored.
No location with id = <id> found

Compare simulation results and modify model data

Change the numerical parameters Iadvec1D from 4 to 1 and Limtyphu1D from 100 to 0 according to SOBEK 3 user manual, section 5.10.2.10 (Parameter set for comparison with SOBEK 2, Deltares Systems, 2013).

Run a simulation with your modified SOBEK 2 model with the channel flow module only.

Validate your SOBEK 3 model with the validation feature.

Validate model tool. This tool is available after right-mouse click on a model. Choose "Validate...".

Check the warning messages and make the necessary changes. Possible necessary changes are:

Add grid points
Re-generate grid

Run a simulation with the corresponding SOBEK 3 model. Compare the results. Results may differ due to changes in the model approach. The following table gives an overview about the differences in model approach between SOBEK 2 and SOBEK 3:

issue	SOBEK 2	SOBEK 3	Modification in SOBEK 2
Controller operations on pumps, handling of initial value	When the initial waterlevel is in the range of the deadband between switch on and switch off level, in SOBEK2 the pump is on	When the initial waterlevel is in the range of the deadband between switch on and switch off level, in SOBEK2 the pump is on.	Change the controller time series in such a way that pump shows the same behaviour in both models. Check the initial water level

Modify the SOBEK 2 model in such a way that the corresponding SOBEK 3 model produces the same results. This is not possible in all cases (Meijer, 2015).

Finalization 1D-Flow

Preface

Within the finalization phase, features that could not be imported from the original SOBEK 2 model must be added:

For lateral stations where the inflow is computed with the rational method, corresponding objects must be modelled in a Rainfall-Runoff model.
Open water nodes from the rainfall-runoff module must be schematized in the D-Flow 1D network.
Hydraulic structures from the rainfall-runoff module must be added to the D-Flow 1D network.

If the model has a long history, modify your model according to good modeling practice:

Remove so-called "Preismann-slots" from all cross-sections.

Consider to use the scripting feature of SOBEK 3. Example scripts are delivered with SOBEK 3.

Lateral stations in 1D-Flow with rational method

If your SOBEK 2 1D-Flow model contains lateral stations that get inflow from rainfall-runoff features like

rational method
rational method with intensity from Rainfall Station

SOBEK User Community > [intermediate] How to migrate SOBEK 2 models to SOBEK 3 > image2015-3-20 11:21:13.png

these features must be added manually within a rainfall-runoff (D-RR) model.

Add a new model to the project:
- right mouse-click on the project, choose "New Model...":
Select "Rainfall Runoff Model"
Move it to integrated model
Import precipitation data (a *.bui file) from your SOBEK 2 model
Create catchments
modify the open water property
- fill in the catchment area
- choose the appropriate Rainfall Station (corresponds to the precipitation data)
connect the catchment to the corresponding lateral node in the water flow 1d network.

References

Deltares Systems (2013): 1D/2D modelling suite for integral water solutions / SOBEK Suite / D-Flow 1D and D-Real Time Control in Delta Shell / User manual. Version: 3.0.1.29328, 30 July 2013 Deltares: Delft, The Netherlands.

Meijer, D. (2015): Results acceptance test FLOW 1D and RTC SOBEK 3. Deltares draft report 1205718-000-DSC-0124-v1.

Velner, R.; Meijers, E.; Ketelaar, H.; Heeringen, J.-J.; Stout, J.; van Putten, H. (2013): Pilot: testen van SOBEK3.1 o.b.v. DeltaShell bij Waterschap Rivierenland. Eindrapport. Waterschap Rivierenland. file: PilotSobekDeltaShellWSRL_Groeidocument_v09_final.doc

Jeuken, M. (2014): Tips bij het converteren van DUFLOW modelschematisaties naar SOBEK 3. Deltares-memo,

You may also want to use visual panels to communicate related information, tips or things users need to be aware of.

Preface

Approach

1D flow

Clean up the SOBEK 2 model

Import to SOBEK 3

Compare simulation results and modify model data

Finalization 1D-Flow

Preface

Lateral stations in 1D-Flow with rational method

References

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