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1D/2D modelling suite for integral water solutions

DR
AF

SOBEK Suite

D-Flow 1D in Delta Shell

User Manual

DR
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T

DR
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SOBEK 3, D-Flow 1D
D-Flow 1D in Delta Shell

User Manual

Released for:
SOBEK Suite 3.7

Version: 3.7.5
SVN Revision: 53926
April 18, 2018

DR
AF

SOBEK 3, D-Flow 1D, User Manual

Published and printed by:
Deltares
Boussinesqweg 1
2629 HV Delft
P.O. 177
2600 MH Delft
The Netherlands

For sales contact:
telephone: +31 88 335 81 88
fax:
+31 88 335 81 11
e-mail:
software@deltares.nl
www:
https://www.deltares.nl/software

telephone:
fax:
e-mail:
www:

+31 88 335 82 73
+31 88 335 85 82
info@deltares.nl
https://www.deltares.nl

For support contact:
telephone: +31 88 335 81 00
fax:
+31 88 335 81 11
e-mail:
software.support@deltares.nl
www:
https://www.deltares.nl/software

Copyright © 2018 Deltares
All rights reserved. No part of this document may be reproduced in any form by print, photo
print, photo copy, microfilm or any other means, without written permission from the publisher:
Deltares.

Contents

Contents
List of Figures

vii

List of Tables

1 A guide to this manual
1.1 Introduction . . . . . . . . . . . . . . . .
1.2 Overview . . . . . . . . . . . . . . . . .
1.3 Manual version and revisions . . . . . . .
1.4 Typographical conventions . . . . . . . .
1.5 Changes with respect to previous versions

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2 Module D-Flow 1D: Overview

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4 Module D-Flow 1D: All about the modeling process
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 Import . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.1 Import modeldata on level . . . . . . . . . .
4.2.2 Import a network from another model on level
4.2.3 Import a network from GIS . . . . . . . . . . . . . . . .
4.2.3.1 The GIS import wizard . . . . . . . . . . . . .
4.2.3.2 Import from personal geodatabase . . . . . . .
4.2.3.3 Import of culvert (profile) data . . . . . . . . .
4.2.4 Import cross section profiles from csv . . . . . . . . . . .
4.2.5 Import time series from csv . . . . . . . . . . . . . . . .
4.3 Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.1 Setting up a network from scratch . . . . . . . . . . . . .

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3 Module D-Flow 1D: Getting started
3.1 Introduction . . . . . . . . . . .
3.2 Starting a D-flow 1D model . . .
3.3 Dockable views . . . . . . . . .
3.3.1 Docking tabs separately
3.3.2 Multiple tabs . . . . . .
3.4 Ribbons and toolbars . . . . . .
3.4.1 Ribbons (shortcut keys) .
3.4.2 File . . . . . . . . . . .
3.4.3 Home . . . . . . . . . .
3.4.4 View . . . . . . . . . .
3.4.5 Tools . . . . . . . . . .
3.4.6 Map . . . . . . . . . .
3.4.7 Scripting . . . . . . . .
3.4.8 Shortcuts . . . . . . . .
3.4.9 Quick access toolbar . .
3.5 Schematization . . . . . . . . .
3.6 Generating a computational grid
3.7 Boundary conditions . . . . . .
3.8 Roughness . . . . . . . . . . .
3.9 Initial conditions . . . . . . . . .
3.10 Model parameter settings . . . .
3.11 Set output . . . . . . . . . . .
3.12 Validation . . . . . . . . . . . .
3.13 Running a simulation . . . . . .
3.14 Viewing simulation results . . . .

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SOBEK 3, D-Flow 1D, User Manual

Nodes and branches . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.2.1 Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.2.2 Branches . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.2.3 Interpolation across nodes . . . . . . . . . . . . . . . . .
4.3.3 Weir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . .
4.3.3.2 Simple weir . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.3.3 Gated weir . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.3.4 Weir with piers . . . . . . . . . . . . . . . . . . . . . . .
4.3.3.5 Weir with detailed description of crest . . . . . . . . . . .
4.3.3.6 Free form weir . . . . . . . . . . . . . . . . . . . . . . .
4.3.3.7 General structure . . . . . . . . . . . . . . . . . . . . . .
4.3.4 Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.5 Culvert, Siphon and Inverted Siphon . . . . . . . . . . . . . . . . .
4.3.6 Composite structure . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.7 Bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.8 Extra Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.9 Lateral Source . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.10 Retention area . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.11 Observation point . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.12 Cross Section . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.12.1 Adding Cross Sections to the network . . . . . . . . . . .
4.3.12.2 Cross Section YZ . . . . . . . . . . . . . . . . . . . . . .
4.3.12.3 Cross Section XYZ . . . . . . . . . . . . . . . . . . . . .
4.3.12.4 Cross Section ZW . . . . . . . . . . . . . . . . . . . . .
4.3.12.5 Cross Section . . . . . . . . . . . . . . . . . . . . . . .
4.3.12.6 Working with Shared Cross Section definitions . . . . . . .
4.3.12.7 Import and export cross sections from/to <.csv>-file . . . .
4.3.12.8 Inspect multiple cross sections in one view . . . . . . . . .
4.3.13 General functions on network objects . . . . . . . . . . . . . . . . .
4.3.13.1 Esc key . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.13.2 Copy and paste network object . . . . . . . . . . . . . . .
4.3.13.3 Add network object . . . . . . . . . . . . . . . . . . . . .
4.3.13.4 Zoom to network object . . . . . . . . . . . . . . . . . . .
4.3.13.5 Selection of multiple network objects . . . . . . . . . . . .
4.4 Boundary conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.1 Types of boundary conditions . . . . . . . . . . . . . . . . . . . . .
4.4.2 Editing boundary conditions . . . . . . . . . . . . . . . . . . . . .
4.4.3 Time series for boundary conditions . . . . . . . . . . . . . . . . .
4.4.4 Remarks on discharge boundary conditions in D-Flow 1D . . . . . . .
4.4.4.1 Simulation results corresponding to discharge boundary conditions . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.4.2 Discharge-waterlevel-relation . . . . . . . . . . . . . . . .
4.5 Initial conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.1 Setting the initial conditions . . . . . . . . . . . . . . . . . . . . . .
4.5.2 Initial conditions from restart . . . . . . . . . . . . . . . . . . . . .
4.6 Roughness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6.2 Defining roughness . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6.3 Import and export roughness from/to csv-file . . . . . . . . . . . . .
4.7 Wind . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.8 Salt water intrusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.9 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.10 Computational grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Contents

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4.11 Model properties . . . . . . . . . . . . . . . . . . . . . . .
4.11.1 Introduction . . . . . . . . . . . . . . . . . . . . . .
4.11.2 General . . . . . . . . . . . . . . . . . . . . . . . .
4.11.3 Initial conditions . . . . . . . . . . . . . . . . . . .
4.11.4 Model settings . . . . . . . . . . . . . . . . . . . .
4.11.4.1 Roughness for tidal flow . . . . . . . . . .
4.11.4.2 Salt water intrusion . . . . . . . . . . . . .
4.11.5 Output parameters . . . . . . . . . . . . . . . . . .
4.11.6 Run parameters . . . . . . . . . . . . . . . . . . .
4.11.6.1 Simulation period and timestep . . . . . . .
4.11.6.2 Restart and save State . . . . . . . . . . .
4.11.6.3 Model parameters . . . . . . . . . . . . .
4.11.6.4 Structure Inertia Damping Factor . . . . . .
4.11.6.5 Extra resistance for general structure . . . .
4.11.6.6 Summerdike . . . . . . . . . . . . . . . .
4.11.6.7 Advanced options . . . . . . . . . . . . .
4.11.6.8 Volumes based on waterlevels or discharges
4.11.6.9 Reduction of timestep on large lateral flow .
4.11.6.10 Use timestep reduction on structure . . . .
4.11.6.11 Parameter set for lowland rivers . . . . . .
4.11.7 Default bed roughness . . . . . . . . . . . . . . . .
4.12 Output . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.13 Validation . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.14 Merge Models . . . . . . . . . . . . . . . . . . . . . . . .
5 Module D-Flow 1D: Simulation and model output
5.1 Simulation information . . . . . . . . . . .
5.2 Results in the Map . . . . . . . . . . . . .
5.3 Results in a Graph . . . . . . . . . . . . .
5.4 Results in a Table . . . . . . . . . . . . . .
5.5 Sideviews . . . . . . . . . . . . . . . . . .
5.5.1 Routes . . . . . . . . . . . . . . .
5.5.2 Results in Sideview . . . . . . . . .
5.6 Export . . . . . . . . . . . . . . . . . . .
5.7 Case analysis . . . . . . . . . . . . . . . .

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6 Module D-Flow 1D: Morphology and Sediment Transport
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2 Input files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.3 Output files . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4 Scripting support . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.1 Generating input files and working with spatially varying input
6.4.2 Dumping and dredging . . . . . . . . . . . . . . . . . . .

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7 Module D-Flow 1D: 1D2D-coupled modelling to D-Flow Flexible Mesh
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7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
7.1.1 Principle of embankments in a 1D2D model . . . . . . . . . . . . . . 109
7.1.2 Principle of the embankment overtopping equations . . . . . . . . . 109
7.2 Integrated 1D2D model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
7.3 Creation of embankments . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
7.3.1 Automatic generation . . . . . . . . . . . . . . . . . . . . . . . . . 111
7.3.2 Import from GIS . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
7.3.3 Merging of embankments . . . . . . . . . . . . . . . . . . . . . . . 112
7.3.4 Draw embankments and changing geometry of existing embankments 113

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7.4

7.5

7.3.5 Inspecting the height of embankments . . . . . . . .
Grid generation . . . . . . . . . . . . . . . . . . . . . . . .
7.4.1 Automatic generation based on embankments . . . .
7.4.2 Grid deletion, modification and manual grid generation
7.4.2.1 Grid deletion . . . . . . . . . . . . . . . .
Simulation output . . . . . . . . . . . . . . . . . . . . . . .

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References

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A How to use OpenDA for Delta Shell models

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B How to use SOBEK 3 models in Delft-FEWS

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D Morphology and Sediment Transport
D.1 Input files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D.1.1 Sediment input file . . . . . . . . . . . . . . . . . . . . . . . . .
D.1.2 Morphology input file . . . . . . . . . . . . . . . . . . . . . . . .
D.1.3 Sediment transport input file . . . . . . . . . . . . . . . . . . . .
D.1.4 Sediment transport and morphology boundary condition file . . . . .
D.1.5 Nodal Relations Definition file . . . . . . . . . . . . . . . . . . . .
D.1.6 Table file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D.2 Output files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D.3 Bedload sediment transport of non-cohesive sediment . . . . . . . . . . .
D.3.1 Basic formulation . . . . . . . . . . . . . . . . . . . . . . . . . .
D.3.2 Calculation of bedload transport at open boundaries . . . . . . . .
D.4 Transport formulations for non-cohesive sediment . . . . . . . . . . . . . .
D.4.1 Van Rijn (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . .
D.4.2 Engelund-Hansen (1967) . . . . . . . . . . . . . . . . . . . . . .
D.4.3 Meyer-Peter-Muller (1948) . . . . . . . . . . . . . . . . . . . . .
D.4.4 General formula . . . . . . . . . . . . . . . . . . . . . . . . . .
D.4.5 Bijker (1971) . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D.4.5.1 Basic formulation . . . . . . . . . . . . . . . . . . . . .
D.4.5.2 Transport in wave propagation direction (Bailard-approach)
D.4.6 Van Rijn (1984) . . . . . . . . . . . . . . . . . . . . . . . . . . .
D.4.7 Soulsby/Van Rijn . . . . . . . . . . . . . . . . . . . . . . . . . .
D.4.8 Soulsby . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D.4.9 Ashida–Michiue (1974) . . . . . . . . . . . . . . . . . . . . . . .
D.4.10 Wilcock–Crowe (2003) . . . . . . . . . . . . . . . . . . . . . . .
D.4.11 Gaeuman et al. (2009) laboratory calibration . . . . . . . . . . . .
D.4.12 Gaeuman et al. (2009) Trinity River calibration . . . . . . . . . . .
D.5 Morphological updating . . . . . . . . . . . . . . . . . . . . . . . . . . .

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C How to use OpenMI for SOBEK 3, D-Flow 1D
C.1 Introduction . . . . . . . . . . . . . . . . . . . . . .
C.2 The omi-file . . . . . . . . . . . . . . . . . . . . . .
C.3 omi file options (for both OpenMI 1.4 and OpenMI 2.0)
C.4 Installing OpenMI for SOBEK 3 models . . . . . . . .

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List of Figures

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Data Import window . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data import window for network (features) . . . . . . . . . . . . . . . . . .
The GIS import wizard . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example of the mapping table . . . . . . . . . . . . . . . . . . . . . . . . .
Import properties window for snapping precision and saving of mapping files
Setting of related tables . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example importing YZ Cross Section from <.csv>-file . . . . . . . . . . . .
Selecting delimiters for a <.csv> file . . . . . . . . . . . . . . . . . . . . .
Selecting the columns of the <.csv>-file . . . . . . . . . . . . . . . . . . .
Linking a Timeseries . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example of boundary nodes . . . . . . . . . . . . . . . . . . . . . . . . .
Two branches with different Order number: No interpolation across the connection node . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Two branches with same Order numbers: Bed level is interpolated across the
connection node . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Simple weir editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gated weir editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Weir with piers editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Weir with detailed description of crest editor, the side-view shows the shape of
the crest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Free form weir editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General structure editor . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pump editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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3.15
3.16
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3.22
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3.24
3.25
3.26
3.27

Docking windows on two screens within the Delta Shell framework. . . . . .
Bringing the Time Navigator window to the front . . . . . . . . . . . . . .
Docking the Time Navigator window. . . . . . . . . . . . . . . . . . . . .
Auto hide the Properties window . . . . . . . . . . . . . . . . . . . . . .
Perform operations using the shortcut keys . . . . . . . . . . . . . . . . .
The File ribbon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Delta Shell options dialog. . . . . . . . . . . . . . . . . . . . . . . .
The Home ribbon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The View ribbon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Tools ribbon contains just the Data item. . . . . . . . . . . . . . . . .
The Map ribbon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The scripting ribbon within Delta Shell. . . . . . . . . . . . . . . . . . . .
The quick access toolbar. . . . . . . . . . . . . . . . . . . . . . . . . . .
Map view with open street background map and a D-Flow 1D branch generated near the city of Rotterdam . . . . . . . . . . . . . . . . . . . . . . .
Example of a cross section . . . . . . . . . . . . . . . . . . . . . . . . .
Example of a weir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Editor for lateral sources/sinks . . . . . . . . . . . . . . . . . . . . . . .
Example of the resulting schematization . . . . . . . . . . . . . . . . . .
Computational grid editor . . . . . . . . . . . . . . . . . . . . . . . . . .
Boundary nodes in the Central Map . . . . . . . . . . . . . . . . . . . .
Constant water level boundary condition . . . . . . . . . . . . . . . . . .
Editing the roughness . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output options in the Properties Window . . . . . . . . . . . . . . . . . .
Output options in the Properties Window . . . . . . . . . . . . . . . . . .
Map results of water level . . . . . . . . . . . . . . . . . . . . . . . . . .
Results of water level for three locations along the branch in Function view .
Chart and the corresponding Properties window . . . . . . . . . . . . . .

3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10
3.11
3.12
3.13
3.14

4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
4.12
4.13
4.14
4.15
4.16
4.17
4.18
4.19
4.20

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4.21 Culvert editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.22 Example of a Composite Structure in the Central Map . . . . . . . . . . . . .
4.23 Region window with a Composite Structure consisting of two weirs, a pump
and a culvert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.24 Bridge editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.25 Editor for lateral source data . . . . . . . . . . . . . . . . . . . . . . . . .
4.26 Generate data series . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.27 Cross Section editor for yz Cross Sections . . . . . . . . . . . . . . . . . .
4.28 Editing window for an XYZ Cross Section . . . . . . . . . . . . . . . . . . .
4.29 Projection of a xyz-cross- section . . . . . . . . . . . . . . . . . . . . . . .
4.30 Cross section editor for ZW Cross Sections . . . . . . . . . . . . . . . . . .
4.31 Cross section editor for Trapezium . . . . . . . . . . . . . . . . . . . . . .
4.32 Switch between Local Cross Section definition and Shared Cross Section definition in the Cross Section editing window . . . . . . . . . . . . . . . . . .
4.33 Example importing YZ Cross Section from <.csv>-file . . . . . . . . . . . .
4.34 Example of a network with nodes with or without boundary conditions . . . . .
4.35 Boundary nodes in the Central Map . . . . . . . . . . . . . . . . . . . . .
4.36 Timeseries on boundary node . . . . . . . . . . . . . . . . . . . . . . . .
4.37 Computational grid of a simple network with a discharge boundary condition
upstream (water flows from right to left). . . . . . . . . . . . . . . . . . . .
4.38 Side-view of computed waterlevels . . . . . . . . . . . . . . . . . . . . . .
4.39 Initial conditions editing window . . . . . . . . . . . . . . . . . . . . . . . .
4.40 write restart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.41 output states . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.42 use restart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.43 Roughness editor for a model of the Dutch part of the river Meuse . . . . . .
4.44 Setting of roughness-sections in the Region window . . . . . . . . . . . . .
4.45 Cross section editor for an XYZ Cross Section with three Sections . . . . . .
4.46 Function table for roughness as a function of discharge and the graphical representation of the table content . . . . . . . . . . . . . . . . . . . . . . . .
4.47 Wind shielding (factors) presented in the Central Map and the table for editing
4.48 Addition of salt in a flow model in the Properties window . . . . . . . . . . .
4.49 Project window after setting Use salinity to “True” . . . . . . . . . . . . . . .
4.50 The use of an advanced dispersion formulation like KuijperVanRijn . . . . . .
4.51 Boundary node editor for salinity . . . . . . . . . . . . . . . . . . . . . . .
4.52 Addition of temperature in a flow model in the Properties window . . . . . . .
4.53 Modelling initial temperature . . . . . . . . . . . . . . . . . . . . . . . . .
4.54 Generate Computational Grid window . . . . . . . . . . . . . . . . . . . .
4.55 Table and map view of the computational grid (note that only waterlevel points
are shown in this view) . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.56 Set output in the Properties window . . . . . . . . . . . . . . . . . . . . .
4.57 Validation Report: example . . . . . . . . . . . . . . . . . . . . . . . . . .
4.58 Merge model workflow . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
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Output in the Project window . . . . . . . . . . . . . . . . . . . . . .
Map results of discharge . . . . . . . . . . . . . . . . . . . . . . . .
Layer properties editor . . . . . . . . . . . . . . . . . . . . . . . . .
Customised map . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Select parameter for graphical representation . . . . . . . . . . . . . .
Time results of water level for 3 locations along the branch . . . . . . .
Example of 3 network routes shown in the network with different colours
Example of the use of intermediate locations to specify routes . . . . .
Example of sideview with Time Navigator . . . . . . . . . . . . . . .
Example of Case analysis . . . . . . . . . . . . . . . . . . . . . . . .

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49
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63
64
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93
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List of Figures

6.1

How to simulate morfology together with a D-Flow 1D simulation

. . . . . . . 105

Principle of the horizontal 1D-2D coupling in a top view and a side view. In
brown the 1D model is schematised. In black the 2D grid is shown. . . . . .
7.2 The variables which control the flow over the interface between the 1D and the
2D model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3 The workflow for the integrated 1D2D model . . . . . . . . . . . . . . . .
7.4 Generate embankments wizard . . . . . . . . . . . . . . . . . . . . . . .
7.5 Embankments created with automatic generation . . . . . . . . . . . . . .
7.6 Merging of two embankments . . . . . . . . . . . . . . . . . . . . . . . .
7.7 Change geometry of an embankment . . . . . . . . . . . . . . . . . . . .
7.8 Sideview of an embankment . . . . . . . . . . . . . . . . . . . . . . . .
7.9 Automatic grid generation. The button is encircled in the top left, the outer
boundary of the grid is drawn in the map view on the right and the final window
‘Generate grid’ is shown on the left . . . . . . . . . . . . . . . . . . . . .
7.10 Different output types within a 1D2D-model . . . . . . . . . . . . . . . . .

. 109
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110
111
112
113
113
113

. 114
. 115

Exporting the DIMR configuration . . . . . . . . . . . . . . . . . . . . . . . 121
Exporting the information on input and output for FEWS . . . . . . . . . . . . 121

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B.2

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List of Tables

List of Tables
Functions and their descriptions within the scripting ribbon of Delta Shell. . . 13
Shortcut keys within the scripting editor of Delta Shell. . . . . . . . . . . . . 13
Shortcut keys within the scripting editor of Delta Shell. . . . . . . . . . . . . 14

4.1

Options for roughness types and default values . . . . . . . . . . . . . . . . 90

D.1
D.2
D.3
D.4
D.5
D.6
D.7
D.8

Sediment input file with keywords . . . . . . . . . . . . . . . . . . . . . .
Options for sediment diameter characteristics . . . . . . . . . . . . . . . .
Morphological input file with keywords . . . . . . . . . . . . . . . . . . . .
Additional transport relations . . . . . . . . . . . . . . . . . . . . . . . .
Transport formula parameters . . . . . . . . . . . . . . . . . . . . . . . .
Nodal relation file with keywords . . . . . . . . . . . . . . . . . . . . . .
Additional transport relations . . . . . . . . . . . . . . . . . . . . . . . .
Overview of the coefficients used in the various regression models (Soulsby
et al., 1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overview of the coefficients used in the various regression models, continued
(Soulsby et al., 1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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3.2
3.2

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1 A guide to this manual
1.1

Introduction
This User Manual concerns the hydrodynamic module D-Flow 1D.
This module is part of several Modelling suites, released by Deltares as Deltares Systems
or Dutch Delta Systems. These modelling suites are based on the Delta Shell framework.
The framework enables to develop a range of modeling suites, each distinguished by the
components and — most significantly — the (numerical) modules, which are plugged in. The
modules which are compliant with the Delta Shell framework are released as D-Name of the
module, for example: D-Flow Flexible Mesh, D-Waves, D-Water Quality, D-Real Time Control,
D-Rainfall Run-off.

1.2

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Therefore, this user manual is shipped with several modelling suites. In the start-up screen
links are provided to all relevant User Manuals (and Technical Reference Manuals) for that
modelling suite. It will be clear that the Delta Shell User Manual is shipped with all these
modelling suites. Other user manuals can be referenced. In that case, you need to open the
specific user manual from the start-up screen in the central window. Some texts are shared
in different user manuals, in order to improve the readability.
Overview

To make this manual more accessible we will briefly describe the contents of each chapter.
If this is your first time to start working with D-Flow 1D we suggest you to read Chapter 3,
Module D-Flow 1D: Getting started. This chapter explains the user interface and guide you
through the modeling process resulting in your first simulation.
Chapter 2: Module D-Flow 1D: Overview, gives a brief introduction on D-Flow 1D.
Chapter 3: Module D-Flow 1D: Getting started, gives an overview of the basic features of the
D-Flow 1D GUI and will guide you through the main steps to set up a D-Flow 1D model.
Chapter 4: Module D-Flow 1D: All about the modeling process, provides practical information
on the GUI, setting up a model with all its parameters, including the output the user wants to
inspect (after the model run), and finally validating the model.
Chapter 5: Module D-Flow 1D: Simulation and model output, discusses how to execute a
model run and explains in short the visualization of results within the GUI.
Chapter 6: Module D-Flow 1D: Morphology and Sediment Transport, discusses the modelling
of Morphodynamic processes and sediment transport.
Chapter 7: Module D-Flow 1D: 1D2D-coupled modelling to D-Flow Flexible Mesh, provides
practical information on the GUI, the lateral coupling of 1D network flow with 2D overland flow
1.3

Manual version and revisions
This manual applies to SOBEK 3 suite, version 3.5 (and higher).

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Typographical conventions
Throughout this manual, the following conventions help you to distinguish between different
elements of text.
Description

Module
Project

Title of a window or a sub-window are in given in bold.
Sub-windows are displayed in the Module window and
cannot be moved.
Windows can be moved independently from the Module window, such as the Visualisation Area window.

Save

Item from a menu, title of a push button or the name of
a user interface input field.
Upon selecting this item (click or in some cases double
click with the left mouse button on it) a related action
will be executed; in most cases it will result in displaying
some other (sub-)window.
In case of an input field you are supposed to enter input
data of the required format and in the required domain.

Example

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1.4

<\tutorial\wave\swan-curvi>

Directory names, filenames, and path names are expressed between angle brackets, <>. For the Linux
and UNIX environment a forward slash (/) is used instead of the backward slash (\) for PCs.

“27 08 1999”

Data to be typed by you into the input fields are displayed between double quotes.
Selections of menu items, option boxes etc. are described as such: for instance ‘select Save and go to
the next window’.

delft3d-menu

Commands to be typed by you are given in the font
Courier New, 10 points.
In this User manual, user actions are indicated with this
arrow.

[m s−1 ] [−]

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Units are given between square brackets when used
next to the formulae. Leaving them out might result in
misinterpretation.

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Changes with respect to previous versions
In the 3.4 edition chapter 7: Module D-Flow 1D: 1D2D-coupled modelling to D-Flow Flexible
Mesh is added.
In the 3.5 edition the Appendix A: How to use OpenDA for Delta Shell models and Appendix B:
How to use SOBEK 3 models in Delft-FEWS have been adjusted.
In the 3.6 edition the following is adjusted:

the model merge functionality is described in section 4.14: Merge Models
the improved Salt dispersion formulation is described section 4.8: Salt water intrusion

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2 Module D-Flow 1D: Overview
D-Flow 1D is one of the models available in SOBEK 3. D-Flow 1D is the product line designed
for the simulation of water flows in open channels. It combines functionality of the former
SOBEK-River Estuary and SOBEK-RIVER and is capable of modelling river systems, estuaries, streams and other types of alluvial channel networks.

The software calculates accurately, fast and robust the one-dimensional water flow for shallow water in simple water systems or complex channel networks with more than thousand
reaches, cross sections and structures. D-Flow 1D solves the full Saint-Venant equations with
the help of the staggered grid numerical scheme (Stelling and Duinmeijer, 2003; Stelling and
Verwey, 2006). In order to model one-dimensional salt water intrusion in estuaries D-Flow 1D
can also solve the Saint-Venant equation and the advection-dispersion equation conjunctively
to account for advective and diffusive/dispersive transport and density driven flow.

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D-Flow 1D allows to apply various types of boundary conditions, as well as to define lateral
inflow and outflow using time series or standard formulae. The networks can be branched
or looped. D-Flow 1D is capable of modelling complex cross-sectional profiles consisting of
multiple roughness sub-sections, e. g. left floodplain, right floodplain and main channel.

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3 Module D-Flow 1D: Getting started
3.1

Introduction
The workflow of setting up a D-Flow 1D model usually consists of the following steps:

Add a D-Flow 1D model to a project
Build or import a schematization
Generate a computational grid
Define roughnesses
Set the boundary conditions
Set lateral sources and sinks (lateral stations) - if there are any
Set initial conditions
Set wind and salt values - if applicable
Adjust model wide settings
Set preferred output
Run a simulation
View and analyze simulation results
Add and combine scenarios or models - if applicable

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These steps are explained in the next paragraph on a small model without wind data and salt
water intrusion. The focus here is on workflow. An overview of the possibilities and options of
the different steps and components is provided in Chapter 4.
3.2

Starting a D-flow 1D model

When SOBEK 3 is started, it opens with an empty project. To get started, import a model or
network that already exists or build a new model from scratch.
A new model is added in the Project window by a right-mouse-click on and choosing Add → and New Model .... A window with all the available models from activated plugins
and the corresponding integrated models appears. Selecting Flow1D Model adds a new 1D
flow model to the project.
The new model is now visible in the Project window. Items in the Project window are sorted
according to the usual workflow for setting up a 1-dimensional flow model as listed above.
3.3

Dockable views

The Delta Shell framework offers lots of freedom to customize dockable views, which are
discussed in this section.

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3.3.1

Docking tabs separately

Within the Delta Shell framework the user can dock the separate windows according to personal preferences. These preferences are then saved for future use of the framework. An
example of such preferences is presented in Figure 3.1, where windows have been docked
on two screens.

Figure 3.1: Docking windows on two screens within the Delta Shell framework.

Multiple tabs

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3.3.2

In case two windows are docked in one view, the underlying window (tab) can be brought to
the front by simply selecting the tab, as is shown here.

Figure 3.2: Bringing the Time Navigator window to the front

By dragging dockable windows with the left mouse button and dropping the window left, right,
above or below another one the graphical user interface can be customized according to
personal preferences. Here an example of the Time Navigator window being docked above
the Properties window.

Figure 3.3: Docking the Time Navigator window.

Additional features are the possibility to remove or (auto) hide the window (top right in Figure 3.3). In case of removal, the window can be retrieved by a mouse-click on Time Navigator
in the View ribbon. Hiding the Time Navigator window results in:

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3.4

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Figure 3.4: Auto hide the Properties window

Ribbons and toolbars

The user can access the toolbars arranged in ribbons. Model plug-ins can have their own
model specific ribbon. The ribbon may be auto collapsed by activating the Collapse the Ribbon
button when right-mouse-clicking on the ribbon.
3.4.1

Ribbons (shortcut keys)

Delta Shell makes use of ribbons, just like Microsoft Office. You can use these ribbons for
most of the operations. With the ribbons comes shortcut key functionality, providing shortcuts
to perform operations. If you press Alt, you will see the letters and numbers to access the
ribbons and the ribbon contents (i.e. operations). For example, Alt + H will lead you to the
Home-ribbon (Figure 3.5).
Note: Implementation of the shortcut key functionality is still work in progress.

Figure 3.5: Perform operations using the shortcut keys

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File

The left-most ribbon is the File ribbon. It has menu-items comparable to most Microsoft
applications. Furthermore, it offers users import and export functionality, as well as the Help
and Options dialogs, as shown in Figure 3.6 and Figure 3.7.

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3.4.2

Figure 3.6: The File ribbon.

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Figure 3.7: The Delta Shell options dialog.

3.4.3

Home

The second ribbon is the Home ribbon (Figure 3.8). It harbours some general features for
clipboard actions, addition of items, running models, finding items within projects or views,
and help functionality.

Figure 3.8: The Home ribbon.

3.4.4

View

The third ribbon is the View ribbon (Figure 3.9). Here, the user can show or hide windows.

Figure 3.9: The View ribbon.

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3.4.5

Tools
The fourth ribbon is the Tools ribbon (Figure 3.10). By default, it contains only the Open
Case Analysis View tool. Some model plug-ins offer the installation of extra tools that may be
installed. These are documented within the user documentation of those model plug-ins.

Figure 3.10: The Tools ribbon contains just the Data item.

The last ribbon is the Map ribbon (Figure 3.11).

Map

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Figure 3.11: The Map ribbon.

This will be used heavily, while it harbours all Geospatial functions, like:

Decorations for the map
North arrow
Scale bar
Legend
...

Tools to customize the map view

Select a single item
Select multiple items by drawing a curve
Pan
Zoom to Extents
Zoom by drawing a rectangle
Zoom to Measure distance
...

Edit polygons, for example within a network, basin, or waterbody
Move geometry point(s)
Add geometry point(s)
Remove geometry point(s)

Creation of a model Network, for example for D-Flow 1D

3.4.6

Add new Branch
Split Branch
Add Cross section
Add Weir
Add Pump
...

Still, all functions of the category can be activated as they will appear in the drop-down panel.

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3.4.7

Scripting
When you open the scripting editor in Delta Shell, a Scripting ribbon category will appear.
This ribbon has the following additional options (see also Figure 3.12), which are described in
Table 3.1:

Figure 3.12: The scripting ribbon within Delta Shell.

Table 3.1: Functions and their descriptions within the scripting ribbon of Delta Shell.

Description

Run script

Executes the selected text. If no text is selected then it will
execute the entire script
Clears all variables and loaded libraries from memory
Enables/Disables the debug option. When enabled you can
add breakpoint to the code (using F9 or clicking in the margin) and the code will stop at this point before executing the
statement (use F10 (step over) or F11 (step into) for a more
step by step approach)
Show or hide python variables (like _var_) in code completion
Determines if spaces or tab characters are added when
pressing tab
Sets the number of spaces that are considered equal to a
tab character
Saves the changes to the file before running
Creates a new region surrounding the selected text
Comments out the selected text
Converts all tab characters in the script to spaces. The number of spaces is determined by Tab size
Converts all x number of space characters (determined by
Tab size) in the script to tabs
Opens a link to the python website, showing you the python
syntax and standard libraries
Opens a link to the Delta Shell documentation website (generated documentation of the Delta Shell api)

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Clear cached variables
Debugging

Function

Python variables

Insert spaces/tabs
Tab size

Save before run
Create region
Comment selection
Convert to space indenting
Convert to tab indenting

Python (documentation)

Delta Shell (documentation)

3.4.8

Shortcuts
The shortcut keys of the scripting editor within Delta Shell are documented in Table 3.2.
Table 3.2: Shortcut keys within the scripting editor of Delta Shell.

Shortcut

Function

Ctrl + Enter
Ctrl + Shift +
Enter
Ctrl + X

Run selection (or entire script with no selection)
Run current region (region where the cursor is in)

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Table 3.2: Shortcut keys within the scripting editor of Delta Shell.

Ctrl
Ctrl
Ctrl
Ctrl
Ctrl
Ctrl
Ctrl
Ctrl
F9
F5

+
+
+
+
+
+
+
+

Function

C
V
S
+
"
W
H

Shift + F5
F10

3.4.9

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F11

Copy selection
Paste selection
Save script
Collapse all regions
Expand all regions
Comment or Uncomment current selection
Add selection as watch variable
Highlight current selection in script (press esc to cancel)
Add/remove breakpoint (In debug mode only)
Continue running (In debug mode only — when on breakpoint)
Stop running (In debug mode only — when on breakpoint)
Step over current line and break on next line (In debug mode
only - when on breakpoint)
Step into current line if possible, otherwise go to next line
(In debug mode only — when on breakpoint). This is used
to debug functions declared in the same script (that have
already runned)

Shortcut

Quick access toolbar

Note: The user can make frequently used functions available by a single mouse-click in the
Quick Access Toolbar, the top-most part of the application-window. Do this by right-mouseclicking a ribbon item and selecting Add to Quick Access Toolbar.

Figure 3.13: The quick access toolbar.

3.5

Schematization

Selecting the Network ribbon will present all icons to add network objects to the schematization. Always start with a channel, but we will come to that shortly. With the Map window,
visualization of the network can be adjusted and map layers can be added. A wms-map layer
can be added by selecting
window.

. After selecting “openstreetmap” the map is added to the main

The zoom button
, the mouse scroll-wheel and the pan zoom button
can be used to
navigate the map. Panning can also be accomplished by holding down the middle mouse
button and moving the mouse. Tip: another way to set for example OpenStreetMap as background is as follows:

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right-mouse-click on in the Project window, and select Add → and New Item

...
select “General” and “Map”
double click on the map
press
on top of the Map window
select “openstreetmap”
and finally right-mouse-click on the map in the Project window, and select “Use as default
background layer”

This way OpenStreetmap will stay as background not only while modelling the schematization
but also on presenting the Calculation grid or the Output.

Now, to follow this tutorial, zoom in on the city of Rotterdam as shown in Figure 3.14.
First activate an icon in the Network ribbon, then click in the Central Map (Flow 1D window)

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to position the activated type of object. Start with a channel Add new branch (Freeform)
.
Press and hold the left mouse button to place the starting point of the branch. As long as
the left mouse button is held down, the branch is drawn following the movement of the mouse
pointer. Releasing the mouse button ends the branch.
Now, to follow this tutorial, model the river section “Nieuwe Waterweg” as shown in Figure 3.14. In this tutorial one branch is used, but more branches can be added and connected
in the same way (see also Section 4.3.2.2). To stop adding branches, press Esc. Note that
the order of the mouse clicks defines the normal direction (i.e. the defined direction) of the
branch, visualized by an arrow at the end of the branch.

Figure 3.14: Map view with open street background map and a D-Flow 1D branch generated near the city of Rotterdam

Selecting
in the Network ribbon activates the addition mode for YZ Cross Sections. When
moving the mouse over the map the orange dot shows where SOBEK places the Cross Sec-

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Y’

0
75
100
150
200
225
300

10
5
-7.5
-10
-7.5
5
10

tion; with a left-click a single Cross Section is added to the branch. Press Esc to leave the
addition mode and double-click on the Cross Section in the map to open the Cross Section
Editor (Figure 3.15). In this chapter we only focus on YZ Cross Sections. The geometry of
the cross section can be specified in the table. Now, to follow this tutorial, fill in the following
values:

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This will result in the Cross Section View given in Figure 3.15.

Figure 3.15: Example of a cross section

Close the Cross Section Editor and select
to add a weir. Like for the cross section, move
the mouse to a location on the branch and left-click to add a weir to the model. Leave the
addition mode by pressing Esc. A double-click on the weir opens the weir editor. Now fill in
the following values:

property
Crest level
Crest width

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Figure 3.16: Example of a weir

to add a lateral source/sink. Move the mouse to a
Close the weir-editor window and select
location on the branch and left-click to add a lateral source/sink. After pressing Esc a doubleclick on the lateral node in the map or on the corresponding entry in the Project window opens
the editor for lateral sources/sinks. Now set the type to Q: Constant flow and the value for the
flow to 500 m3 s−1 like shown in Figure 3.17.

Figure 3.17: Editor for lateral sources/sinks

The schematization now looks like Figure 3.18. Note that the extent of the Cross Section
is shown on the map. Note also that the network components are shown in the Region
window. For now, we leave the schematization as it is. For a review of all the options for
schematizations, see Chapter 4.

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Figure 3.18: Example of the resulting schematization

3.6

Generating a computational grid

Once a schematization exists a computational grid can be generated. The computational grid
is not a part of the network, but a separate layer, which can be re-used for or linked to other
models or scenarios and redefined without influencing the network elements.
A computational grid is generated by a right-click on in the Project
window and selecting Generate Computational Grid Nodes.... A window pops up (Figure 3.19)
with a number of options, which are described in more detail in Section 4.10. For now we
focus on maximum length, which determines the distance between calculation points. Select
Prefered length and set the value to 1000 meters. After pressing OK the grid is generated
and presented. For more information on the computational grid, see Section 4.10.

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Figure 3.19: Computational grid editor

3.7

Boundary conditions

The boundary conditions are edited by double-clicking in the Project window. In the Central Map the boundary nodes are presented on the map and listed in a table.

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Figure 3.20: Boundary nodes in the Central Map

Right-mouse-clicking on one of the nodes in the table and selecting Open View ... opens an
editor. The following types of boundary conditions can be selected:

None
H(t): Water level time series
Q(t): Discharge time series
Q(h): Discharge Water level table
Q : Constant Discharge
H : Constant Waterlevel

Now, to follow this tutorial, select a constant flow of 800 m3 s−1 at the start of the branch (most
upstream point), and a constant waterlevel of 1 m at the end of the branch (most downstream
point), as shown in Figure 3.21.

Figure 3.21: Constant water level boundary condition

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3.8

Roughness
Branch roughness can be defined for different parts of the cross sections, defined as roughness-sections. Open the Cross Section Editor to view the definition of the sections, in the
table underneath the graphical representation. The roughness-section is visualized by the
block under the cross section in the graphical representation. For the simple model discussed
in this chapter, keep a single roughness-section.

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Notice that the model wide roughness-type and -value can be edited in the Properties window
after selecting Main under (Figure 4.43). Press the "+" in front
of to unfold. For now, in this simple model, the default roughness is not
changed and no detailed roughness value is defined for the branch. More information on
setting roughness is found in Section 4.6.

Figure 3.22: Editing the roughness

3.9

Initial conditions
There are two basic initial conditions:

initial waterlevel or depth; and
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initial water flow (discharge)

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Both can be specified. The user can choose between initial waterlevel or depth by selecting the model in the Project window and the Initial conditions section in the
Properties window.

Figure 3.23: Output options in the Properties Window

Now, for this tutorial, change the definition from Depth to Waterlevel, then set its Default value
to “1”. Note that in the Project window has now changed to . Leave the initial water flow as it is.
3.10

Model parameter settings

Some parameters need to be set before a model run. By selecting Project window , the simulation settings for the model appear in the Properties window. There are several parameters, which can be edited, but the most important are StartTime, StopTime and
TimeStep. The parameters StartTime and StopTime define the simulation period. The parameter TimeStep defines the maximum time step with which the simulation is performed. Whenever and wherever in the schematization the numerical scheme requires a smaller timestep
to ensure computational stability, the program will reduce the timestep as necessary. Please
note that the automated reduction of timestep is only done to prevent model crashes. Based
on the modelled hydrodynamic phenomena, users should select appropriate space-steps as
well as an appropriate timestep to ensure that the hydrodynamic phenomena involved are
computed with sufficient accuracy.
Now, to follow this tutorial, set the simulation period to 3 d by adjusting and

. Set the to 1 h.

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3.11

Set output
Left-click on Project window . The Properties Window now shows all
possible output options, see Figure 3.24.
Choose the following output parameters and set the output value on “Current”:

Grid points: Water level
Reach segments: Discharge
Reach segments: Velocity
Simulation info: Number of iterations
Structures: Crest level

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Set the rest of the parameters to “None”. Set both output timesteps to 1 h.

Figure 3.24: Output options in the Properties Window

3.12

Validation

As a final step in the modelling process, the user can activate the validation tool, by rightmouse-click in the Project window on and selecting Validate.... The validation
tool checks all that is required for a model run. In other words: a validated model will run!
3.13

Running a simulation
The simulation can now be started by a right-mouse-click on Project window
and selecting Run model. A window pops up in which the progress of the simulation is shown.
The window disappears when the simulation is finished.
In the Project window the results are added to the model under . Here the run
report can also be found. This is a log with all the messages during the simulation from both
Delta Shell and D-Flow 1D.

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Viewing simulation results
The simulation results can now be examined and analyzed in several ways, described in detail
in Chapter 5.

Double-clicking on Project window will present the water level results
on the map together with the network as coloured symbols on the calculation points. The
initial values of the water level will be presented first. Now, activate the Time Navigator. You
can move through the results as a function of time by moving the slider (Figure 3.25). On
the left side of the map view, the results in table are visible for the specified time in the Time
Navigator window.

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3.14

Figure 3.25: Map results of water level

Press and hold the Ctrl key, then left-click on three locations in the map view of the water level
results. The three locations are all selected. Make sure you choose a value upstream of the
weir node, downstream of the weir node and downstream of the lateral source/sink node. Now
left-click on the Query Time Series icon
in the Tools ribbon to get the time series of the
results. A window pops up in which you can choose one or more parameters. Select water
level and press OK. Note that it is possible to choose a parameter different than water level
even though the locations were selected in a water level map view. A new tab now opens with
a graphical view (the Function view) of the requested time series on the right and a table
with the depicted results on the left (Figure 3.26).
Returning to the map view and selecting new locations and an output parameter adds a new
line to the Function view after clicking the Get time series icon. Change the curves in the
Function view in the Chart window (Figure 3.27).

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Figure 3.26: Results of water level for three locations along the branch in Function view

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Figure 3.27: Chart and the corresponding Properties window

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4.1

Introduction

4.2.1

Import

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4.2

Import
Network (schematization)
Boundary conditions
Initial Conditions
Roughness
Wind data
Salinity
Computational Grid
Parameter settings
Validation
Output

This chapter describes the functionality of the D-Flow 1D plug-in:

Import modeldata on level

On the project level, data from other models or full Delta Shell projects can be imported by
a right-mouse-click in the Project window on and choosing Import. . . . Figure 4.1
shows the resulting pop-up screen. Different data types can be imported:

a Project (SOBEK 3)
a network from a geographical information system (GIS)
a NetCDF regular two-dimensional grid
a Raster File
a Time series (<.csv>)
a Time-dependent grid
a SOBEK model or network (works for SOBEK-RE and SOBEK 2)

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Figure 4.1: Data Import window

In case of importing a SOBEK model the user can choose between different options. Note
that the data will be stored at the Project level. This implies that for example the imported
network is not connected to any existing model in the Delta Shell project. At a later stage the
network can be linked by dragging the network onto the flow model 1d in the Project window.
4.2.2

Import a network from another model on level

In case of an existing D-Flow 1D model, the network, the network objects and cross sections
(with profile data) can be imported to complete or update the model on the level.
Right-click on on an existing D-Flow 1D model in
the Project window. Figure 4.2 shows the resulting pop-up screen. The following options are
available:

SOBEK data
Model features from GIS
data in text files (<.csv>) for three types of cross sections

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Figure 4.2: Data import window for network (features)

4.2.3
4.2.3.1

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By selecting the appropriate import a wizard window pops up. After completing the wizard,
the data is imported and added to the Project window. Data already existing in the D-Flow 1D
model is overwritten with the imported data.
Import a network from GIS
The GIS import wizard

To import a network with its objects a GIS import wizard is available. The wizard can be
addressed on a level (Section 4.2.2) or on a level (Section 4.2.1).
The wizard imports the network itself or network features from a shapefile or from a
personal geodatabase . Always start with the Channels. Figure 4.3 shows the GIS
import wizard.

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Figure 4.3: The GIS import wizard

A complete network consists of a combination of different network features from several
shapefiles or tables in a personal geodatabase. Here, the description is limited to the import
from shapefiles. In Section 4.2.3.2 the specifics of importing from a personal geodatabase
is described. Several network objects can be imported simultaneously by selecting Features
with the -file and adding it (
) to the (import)list (Figure 4.3). When all
the required features are set, click Next. Another window appears with the mapping table
(Figure 4.4).

Figure 4.4: Example of the mapping table

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Here, columns in the shapefiles can be related to D-Flow 1D network objects. After defining
the mapping and confirmation with Next the Import properties window appears where the
user can set the snapping precision (Figure 4.5). Network objects like weirs or cross sections
in the -file will be snapped to the nearest branch during import, unless they are farther
from any branch than the snapping precision specified in the Import properties window. In
the latter case, the network objects are discarded during the import.

Figure 4.5: Import properties window for snapping precision and saving of mapping files

. A mouse-click on this button
Another important button in this screen is
saves the entire mapping of the different shapefiles. Instead of having to walk through all
above-mentioned steps to import a network, the next import from a similar set of shapefiles
(or personal geodatabase) can be handled by a mouse-click on
Figure 4.3.
4.2.3.2

Import from personal geodatabase

To import network objects from a personal geodatabase, the user must activate the GIS import
wizard, described in the previous paragraph. Here, the specifics on importing from a personal
geodatabases are described.
In case the user selects a personal geodatabase in the first screen of the GIS import wizard,
the user must also set the correct feature class in Table before adding the feature to the
import-list.
Some features have additional tables which have to be taken into account. For example, cross
sections often have separate tables for the profile data. Relating tables can be added by a
mouse-click on
in the GIS import window. The relations between the base table and a
related table are set in another window, an example is given in Figure 4.6. Similarly to joining
of tables in ESRI ArcGIS, the related tables and the matching ID-column are set. It is also
possible to filter specific columns or values.

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Figure 4.6: Setting of related tables

4.2.3.3

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Mark, that adding features to the import-list, mapping, snapping and import all work the same
as for shapefiles.
Import of culvert (profile) data

In case of an existing D-Flow 1D model network, GIS data for culverts can be imported. The
AQUO standaard is applied, see http://www.aquo.nl/aquo/lm_aquo/element/
KDUVORM.htm. The following shapes are recognized (dutch):

Round - default
Rectangle
Egg (Dutch: ’eivormig’)
Cunette (Dutch: ’muil’)
Ellips
Arch (Dutch: ’heul’)

The latter type is converted to a round culvert. Of course, to achieve this the ’shape’ must be
mapped. In addition, the ’height’, ’width’ and ’diameter’ of a culvert can be mapped as well.
These will be recognised and imported into the /dflowoned model network.
4.2.4

Import cross section profiles from csv

Cross sections (location and profile) can be imported from <.csv>-files. This can be done
either by a right-mouse-click in the Project window on and selecting Import ... or by a right-mouse-click in the Central Map and selecting
Import cross section(s) from csv. After selecting the <.csv>-file, the following window popsup:

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Figure 4.7: Example importing YZ Cross Section from <.csv>-file

The screenshot above shows the columns SOBEK 3 requires. An example file can be obtained
by exporting some cross sections.
By default, cross sections with the same Name will be replaced. By de-selecting Import
chainages the location of the original cross section can be left unchanged. In that case, the
column can be left empty. By default, the option Create cross section if Name was not found
in the network is activated.
Note: that the import from <.csv>-file described here can be used to replace the (profile)data of present cross sections. This way, the import of cross sections is a two-step process:

first import the cross sections (location) by the GIS import wizard (see Section 4.2.3) - a
default profile will be added;

then import the cross section profiles from csv described here. De-select Import chainages.

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Import time series from csv

A timeseries of waterlevels or discharges can be imported by a right-mouse-click in the
Project window on and selecting Import... and Time series (csv). A wizard opens
in which a <.csv>-file can be selected and the delimiters between the columns can be set
(Figure 4.8).

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4.2.5

Figure 4.8: Selecting delimiters for a <.csv> file

The columns with the date-time and the data are specified as shown in Figure 4.9.

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Figure 4.9: Selecting the columns of the <.csv>-file

The timeseries is added to the project and can be used as a boundary condition or lateral source. Link the timeseries by selecting and dragging it in the Project window onto a
or onto .

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Figure 4.10: Linking a Timeseries

4.3
4.3.1

Network

Setting up a network from scratch

To build a model schematization from scratch, add a new model to the project (right-mouseclick on in the Project window, select Add → Flow 1D)
By double-clicking on in the model input in the Project window, the network will
be presented in the (central) map. In the Map / Network ribbon there are several buttons to
add network objects like

branch
node
cross section
structure: weir, pump, culvert, bridge
extra resistance
retention
lateral source/sink

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observation point

4.3.2.1

Nodes and branches

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4.3.2

node
cross section
weir
pump
culvert and siphon
bridge
extra resistance
retention
lateral source/sink
observation point

are activated. Pressing the Esc key ends the editing mode, the selection tool is activated.
Double-clicking on a network element either in the Central Map or in the Region window
opens the corresponding editor in a new tab. A network consists of point elements and line
elements. Branches are the only type of line elements, but there are multiple point elements:

Nodes

Nodes are the basis of any network. They define the limits of branches and the network itself.
If a node forms the boundary of the network, often a boundary conditions is set at the node.
therefore changes the length and geometry of branches. The location
Moving a node
of a node is defined by x-y -coordinates which can be adjusted in the Properties window of
the node.

Figure 4.11: Example of boundary nodes

A node can belong to a single branch - where it will limit the network - or to more branches.
Figure 4.11 shows an example of two connected branches. The node connecting the two

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branches is solid green. The connection node works as a boundary between branches. The
characteristics of the branches are not interpolated across the connection node. Instead, the
waterlevel and discharge are transfered from one branch to the next. When selecting the
branch, the curvepoints are shown as green squares. The branch direction is shown by a blue
arrow. Most users will use the direction of the flow. The branch direction can be reversed by
right-clicking the branch in the map and selecting Reverse direction.
The table below the Central Map contains a tab with all nodes in the network. Nodes can be
selected in the map and in the Attribute Table. Nodes are added automatically when a new
branch is drawn, but can also be added or removed by a right-mouse-click in the Central Map
and selecting Insert node or Remove node. Boundary nodes can not be removed.
Branches

A branch is a line object between two nodes. With a branch, the course of a river, channel or
stream is schematised. A branch always has a geometry and hydraulic characteristics:

A start and end location (nodes), which determine the boundaries of the branch and the
length

Curvepoints (which set the curvature-geometry)
Dimensions (cross sections)
A resistance (hydraulic roughness)

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4.3.2.2

In addition, there can be additional branch-features, such as structures or lateral sources. For
adding branches the Map / Network ribbon of D-Flow 1D provides several tools. Create new
branches
or
by point and click
automatic curve points .

In this editing mode an additional branch can be connected by re-using a node of the existing
branch. Two existing branches can be connected by drawing a new branch using the nodes
of the existing branches. These nodes will change to solid green.
Reposition an existing branch

by adding curve points with
moving a single curve point with
or moving the branch as a whole from a selected curve point with

These move features can also be used for other network elements. To reverse the branch
direction right-click the branch in the map with the mouse and select Reverse direction.

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Interpolation across nodes

By default, the characteristics (cross section, bed level and roughness) of a branch are not
interpolated across a connection node. Instead, the waterlevel and discharge are transfered
from one branch to the next. In case of a single river or channel this might lead to unrealistic
and undesired flow.

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4.3.2.3

Figure 4.12: Two branches with different Order number: No interpolation across the connection node

To avoid this the Order number of branches is introduced. Cross sections, bed level and
roughnesses are interpolated across a connection node when the branches have the same
Order number. By specifying the same Order number for branches of the main river, a tributary can be distinguished by a different Order number. The characteristics of the main river
will be interpolated, resulting in a smooth flow. This can be achieved as follows:

Press the Esc key
Select the first branch by a left-click on the map
Hold the Ctrl key while selecting the next one; or
Hold the Shift key while selecting another branch: the shortest route will be selected
(the selection will be high-lighted)
While holding the Ctrl key, a left-click will de-select a branch

Now the user can modify the Order number of all selected branches in the Properties window.

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Figure 4.13: Two branches with same Order numbers: Bed level is interpolated across
the connection node

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In case the user starts to model from scratch, the Order number of branches is set to "-1" (no
interpolation). It is advised to change the Order number, as the application will then apply the
Order number for new branches, according to the following rules:

a new (continuous) branch gets the same Order number
a new branch at a junction gets a higher Order number
after splitting a branch the new branch gets the same Order number

All branches of an imported SOBEK 2 model will have the default Order number of "-1". For
compatability the Order numbers of branches are adjusted in line with the concept of Linkage
node. This concept has been discarded in SOBEK 3 3.
4.3.3
4.3.3.1

Weir

Introduction

A weir is a point object on a branch that limits the flow in that branch by adding a physical
blockage with certain dimensions, representing a hydraulic structure in the real world. Weir
objects can model three types of flow:

free flow
submerged flow
no flow

A weir can be simple or more complicated, which results in the following types (where the
term in brackets is the corresponding name in SOBEK 2):

Simple weir (Weir)
Gated weir (Orifice)
Weir with piers (Advanced weir)
Weir with detailed description of crest (River weir)
Free form weir (Universal structure)
General structure

Each type of weir has a specific shape and parameters to be set. For a detailed description of

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the underlying mathematical model we refer intermediately to the technical reference manual
(SOBEK2, 2012).
in the Map / Network ribbon. Then
A weir can be added to the network by clicking on
click on the preferred location in the network to position the weir. The weir is snapped to the
nearest location on a branch. A second way to add a weir to the network is by right-mouseclick in the Region window, on the branch, and select select Add Weir. The weir is added at
zero chainage. This can be adjusted in de Properties window.
Double-clicking the weir object in the Central Map or in the Region window opens the weir
editor in a new tab. The editor window has the following elements:

between structures in the composite

structure settings.

a graphical representation of the structure in side view and in cross section view
a tab with the structure-ID, which can be used in composite structures to switch easily

4.3.3.2

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Some of the structure properties can also be edited in the Properties window or the Attribute
Table.
Simple weir

The editor for a simple broad-crested weir is shown in Figure 4.14. For a simple weir the
following parameters can be adjusted in the editing window:

Crest level: the height of the weir crest in meters
Crest width: the width of the weir in meters
Allowed flow direction, Positive
Allowed flow direction, Negative
Discharge coefficient Ce (dimensionless): the default value is 0.8.
Lateral contraction coefficient Cw (dimensionless): the default is 1.0

Figure 4.14: Simple weir editor

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4.3.3.3

Gated weir
The editor for a gated weir is shown in Figure 4.15. Editable parameters for a gated weir are:

Crest level: the height of the weir in meters
Crest width: the width of the weir in meters
Lower edge level: the lower edge of the gate in meters
Gate opening: distance between weir crest and gate lower edge in meters
Allowed flow direction, Positive
Allowed flow direction, Negative
Max: a maximum discharge [m3 s−1 ] for both the positive and negative allowed flow directions
Discharge coefficient Ce : default is 0.8
Lateral contraction coefficient Cw : default is 1.0

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The lower edge gate level is automatically set when the crest level and/or the opening height
are adjusted. Similarly, when the lower edge gate level is adjusted, the gate opening is automatically adjusted as well.

Figure 4.15: Gated weir editor

4.3.3.4

Weir with piers
The editor for a weir with piers is shown in Figure 4.16. Editable parameters for a weir with
piers are:

Crest level: the height of the weir in meters
Crest width: the width of the weir in meters
Number of piers
Upstream face P : height of the weir relative to the bed level at the upstream side in
meters. The default value is 10 m

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Design head of weir flow H0 : the head for which the structure was designed. The default
value is 3 m

Pier contraction coefficient Kp : coefficient representing the net sill-width reduction due to

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the presence of piers. The value depends on the shape of the piers, the default value is
0.01
Abutment coefficient Ka : coefficient representing the net total flow width reduction due to
the presence of abutments. The value depends on the shape of the abutments, default
value is 0.01

Figure 4.16: Weir with piers editor

4.3.3.5

Weir with detailed description of crest

For a “weir with detailed description of crest” the crest shape can be set in addition to the crest
level and the crest width. In a drop-down menu the user can choose between:

Broad
Sharp
Round
Triangular.

Figure 4.17 shows the editor. In the side-view the structure shape changes with the type
of crest. Furthermore, the following energy loss properties must be specified for each flow
direction:

Correction
Submerge
Reduction table: reduction coefficient as a function of the head
Default values are provided.

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Figure 4.17: Weir with detailed description of crest editor, the side-view shows the shape
of the crest

4.3.3.6

Free form weir

Free form weirs can be defined by a Y-Z profile. The weir consists of rectangular sections
having a horizontal bed and triangular sections having a sloping bed. It is assumed that the
total discharge over a free from weir is the sum of the discharge over each section, where
rectangular weir sections are considered as a simple weir and a triangular weir sections are
considered as (the half of) a broad-crested weir with truncated triangular control section.
Figure 4.18 shows a typical free from weir, suitable for fish to pass the weir - even at low
discharge. The following parameters can be adjusted in the editing window:

Y’, Z table (minumum of 2 values)
Allowed flow direction, Positive
Allowed flow direction, Negative
Discharge coefficient Ce (dimensionless): the default value is 0.8.

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Figure 4.18: Free form weir editor

4.3.3.7

General structure

This type of weir is a special kind of gated weir with additional information on the geometry
and the possibility of drowned gate flow and drowned weir flow. For more information see the
Technical Reference Manual. Figure 4.19 shows the editor. Editable parameters are

Lower edge level: gate lower level in m AD
Gate opening: height in m
Level and width: table with levels in m AD and widths in meters for upstream location 1

and 2, and downstream locations 1 and 2, see for a detailed explanation the Technical
Reference Manual.
Coefficient free gate flow: coefficient representing the contraction for free gate flow
Coefficient drowned gate flow: coefficient representing the contraction for drowned gate
flow
Coefficient free weir flow: coefficient representing the contraction for free weir flow
Coefficient drowned weir flow: coefficient representing the contraction for drowned weir
flow
Contraction coefficient

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Figure 4.19: General structure editor

4.3.4

Pump

To add a pump object click on
in the Map / Network ribbon. Then click on the preferred
location in the network to position the pump. The pump is snapped to the nearest location
on a branch. A second way to select add a pump to the network is by right-mouse-click in
the Region window, on the branch, and select select Add Pump. The pump is added at zero
chainage. This can be adjusted in de Properties window.
By double-clicking on the pump in the Central Map or in the Region window, the pump editor
is opened in a new tab. The pump editor is shown in Figure 4.20. For a pump the editable
parameters are

Pump capacity in m3 s−1
Pump direction (positive or negative)
Switch-on and -off levels for both the suction side and the delivery side. The switch-on
levels are depicted by a black line in the cross section view, the switch-off levels by a red
line
A reduction table can be specified optionally

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Figure 4.20: Pump editor

In D-Flow 1D a pump can only have one capacity and one set of switch on/off levels. A pump
with multiple capacities and multiple switch on/off levels is modelled as a composite structure
(see ??) consisting of several pumps.
4.3.5

Culvert, Siphon and Inverted Siphon

In order to model pipe-shaped structures that connects two open channels, for example a pipe
underneath a road connecting two waterways, D-Flow 1D provides three different structure
features:

Culvert
Siphon
Inverted Siphon

Culvert, Siphon and Inverted Siphon can be equipped with gates. The discharge through a
culvert is affected by the upstream and downstream invert levels, its shape, size and length
and the material.
in the Map / Network ribbon. Then click on the
A Culvert can be added by clicking
preferred location in the network to position the Culvert. The Culvert is snapped to the nearest
location on a branch. A second way to add a culvert to the network is by right-mouse-click
in the Region window, on the branch, and select select Add Culvert. The culvert is added at
zero chainage. This can be adjusted in de Properties window.
By double-clicking on the culvert in the Central Map or in the Region window, the Culvert
Editor is opened in a new tab.

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Figure 4.21: Culvert editor

Parameters that can be specified are:

Length: length of the culvert in m
Groundlayer: roughness type and value. For roughness type the options are
Chézy (C )
Manning (nm )
Strickler (kn )
Strickler (ks )
White and Colebrook

Geometry type

Tabulated
Round
Egg
Rectangle
Ellipse
Arch
Cunette
SteelCunette

In the Culvert editor it is also possible to check the
box. The Culvert is then treated
as a siphon with an On/Off level. The On level and the Off level are displayed in the side-view
of the editing window. The user also has to specify a Bend loss coefficient. In addition, the
siphon may be inverted. By unchecking the
box but leaving the Bend loss coefficient
unequal to 0, the culvert is treated as an Inverted Siphon. And finally, a gate can be added by
checking the

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, and specifying Initial gate opening and Lower edge level.

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4.3.6

Composite structure

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A composite structure is a combination of multiple structures of the same type or different
types. D-Flow 1D distributes the water to the structures according to the mathematical models
of the structure objects. An example of a composite structure (also: compound structure)
is given in Figure 4.22. In the Region the structure objects forming together a D-Flow 1D
Composite Structure are summarized under StructureFeature (Figure 4.23). In the Properties
window of a Composite Structure the number of structure objects is displayed. To create a
composite structure, add multiple structure objects to the same location.

Figure 4.22: Example of a Composite Structure in the Central Map. Multiple structure
objects (here: two Weirs, a Pump and a Culvert) are arranged horizontally,
the bar below the structure icons indicates that the structures are combined
to a Composite Structure. The Attribute Table lists the sub-structures of
Weir type

Figure 4.23: Region window with a Composite Structure consisting of two weirs, a pump
and a culvert

4.3.7

Bridge
A bridge forms a resistance for water flow that depends on the cross section under the bridge
and the shape of the pillars. There are three types of bridges (where the term in brackets
corresponds to SOBEK 2 terminology):

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Rectangle (fixed-bed and soil-bed bridge)
Tabulated (abutment bridge)
Pillar (pillar bridge)

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Add a Bridge to the model network by clicking the Add Bridge tool
in the Map / Network
ribbon. Then click on the preferred location in the network to position the Bridge. The Bridge
object is snapped to the nearest location on a branch. A second way to add a bridge to the
network is by right-mouse-click in the Region window, on the branch, and select select Add
Bridge. The bridge is added at zero chainage. This can be adjusted in de Properties window.

Figure 4.24: Bridge editor

By double-clicking on the Bridge in the Central Map or in the Region window, the bridge editor
is opened in a new tab. The bridge editor is shown in Figure 4.24. For a bridge the editable
parameters are:

Geometry of the (cross sectional) flow-area, choose between
Rectangle: specify the cross section geometry in a table
Tabulated: specify the cross section geometry in a table

Pillar: fill in the fields for the width between the pillars and the shape factor
Length: the length of the bridge along the course of the river in [m], displayed in the
side-view

Roughness Type: choose between
Chezy
Manning
Strickler (kn and ks )
White-Coolebrook

the corresponding roughness value (the unit depends on the roughness type)
a Ground layer roughness option
Allowed flow direction (positive, negative or both)

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Inlet loss and Outlet loss
4.3.8

Extra Resistance
An Extra resistance object can be used to model sill beams or other obstacles in the channel
in
not further specified or to to adjust the water distribution in a bifurcation. By clicking
the Map / Network ribbon, the user can add an Extra resistance object. A double-click on the
Extra resistance object in the Central Map or in the Region window opens the editor with the
following editable parameters:

Choice of two formulas to compute the extra resistance
A table that defines the extra resistance parameters depending on the waterlevel

Lateral Source

A lateral source (sink) is a volume of water entering (leaving) the model at a location on
a branch within a certain period of time. As a sink can be interpreted as a source with a
negative sign, the corresponding object in D-Flow 1D has been named “Lateral Source”.

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4.3.9

For a detailed description, see the Technical Reference Manual, the section on the Momentum
equation (1D).

in the Map / Network ribbon. Then click on the preferred
To add a Lateral Source click
location in the network to position the Lateral Source. The object is snapped to the nearest
location on a branch. A second way to add a Lateral Source to the network is by right-mouseclick in the Region window, on the branch, and select select Add Lateral. The Lateral Source
object is added at zero chainage. This can be adjusted in de Properties window. Mark the
difference between Lateral source on selection in the Region window, and Lateral source
boundary data on selection in the Project window.
Now that the Lateral Source is positioned on the network, the volume of water can be defined
either as constant or as a function of time or waterlevel.

Figure 4.25: Editor for lateral source data

A time series can be generated by a right-mouse-click in the Project window on and selecting Generate data in series.... Figure 4.26 shows the popup screen, where Start, End and Interval can be set. By clicking on Generate data a table is

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generated with a constant discharge. The user can change the discharge values by opening
the editor for lateral source data (Figure 4.25). This editor is evoked with a double-click in
the Project window on . A positive value for discharge
represents water flowing into the system, a negative value means water flowing out of the
system. It is good modeling practice to limit the lateral inflow or outflow to 10 % of the channel
flow.

Figure 4.26: Generate data series

It is also possible to use a Timeseries which is available in the . Chapter Section 4.2.5 describes how a Timeseries can be imported and linked to a Lateral source.
4.3.10

Retention area

By clicking
in the Map / Network ribbon the user can add a Retention area object. The
Retention area parameters can be edited in the corresponding Properties window.
4.3.11

Observation point

in the Map / Network ribbon allows to add an ObserClicking the Add Observation Point
vation Point to the network. At Observation Points the simulated

discharge
velocity
depth
waterlevel

can be visualized at a smaller time step than for the calculation points (see Chapter 5). Observation Points are often used as input locations for D-RTC flow charts or they represent a
gauge in the real-world river system and so become a location of interest.
4.3.12

Cross Section

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Adding Cross Sections to the network
A Cross Section is added in two steps. First, select the type of cross section by activating one
of the following tools from the Map / Network ribbon:

Add Cross Section YZ
Add Cross Section ZW
Add Cross Section XYZ
Add Cross Section

with a rectangle, arch, (steel)cunette, ellipsis or trapezium profile

for a cross section with a default definition. This default definition must be specified
previously in the Region window as described in Section 4.3.12.6.

Second, add the Cross Section by clicking on the preferred network location. The Cross
Section object snaps to the nearest location on a branch. To leave the network editing mode,
press Esc.
It is also possible to add a cross section to the network by right-mouse-click in the Region
window, on the branch, and selecting Add Cross Section YZ ... or Add Cross Section ZW ....
In the pop-up window the chainage and Z Level shift can be specified.

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4.3.12.1

The cross sections can now be edited by double-clicking on the Cross Section object in the
Central Map or in the Region window, or by selecting the Cross Section in the Attribute
Table below the Central Map, right-mouse-clicking and selecting Edit. This is described in
more detail in the following parapraphs.

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Cross Section YZ

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4.3.12.2

Figure 4.27: Cross Section editor for YZ Cross Sections with table (left) and graphical represenation of the cross section geometry. The vertical line indicates where
the cross section crosses the branch line. The two highlighted points in the
diagram correspond with the selected row in the table. Below the graphical
representation is the table the roughness information (see Section 4.6)

Figure 4.27 shows the editing window for Cross Sections. On the left there is a table with
the yz -coordinates of the cross section. On the right a graphical representation of this table
content is given. The cross section geometry can be modified in the table or in the diagram.
While navigating in the table the points corresponding with the active row are highlighted in
the diagram. Extra storage volume can be created by adding a positive value in the column
∆z Storage of the yz -table or dragging the points in the diagram - upwards only. The storage
volume is visualized in the graph as a shaded area. This part of the cross section is not
considered as cross sectional flow area. In the diagram the cursor switches automatically
from add mode to drag mode. In case of zero storage the Total and Flow profile are equal
(double line). Hold the Alt key and drag to modify both profiles. Move the mouse while holding
the left mouse button pressed to the right and down to zoom in, and to the left and down to
zoom out. Move the dotted vertical line to shift the cross section with respect to the branch
line (thalweg). Note that also the roughness sections are defined in the Cross Section editor,
for a full description see Section 4.6.

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Cross Section XYZ

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4.3.12.3

Figure 4.28: Editing window for an XYZ Cross Section

Cross Sections of XYZ-type are similar to YZ Cross Sections, but they are usually drawn
directly on the map, so the cross section points are not necessarily arranged on a line orthogonal to the branch line. Figure 4.28 shows the editing window for an XYZ Cross Section.
The editing window for XYZ Cross Sections is similar to the one for YZ Cross Sections (Section 4.3.12.2), but the table shows y 0 values in the first column. These are the projected values
along a straight line as shown in Figure 4.29. As SOBEK is a 1D model, the geometry has to
be projected to a single location on the branch. This projection is length-conserving; the total
length of the cross section is maintained. The first location has offset 0, the end location has
offset L.

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Figure 4.29: Projection of a xyz-cross- section

Use the Move Feature tool
the table can not be edited.
4.3.12.4

to adjust the points in the horizontal plane. The y 0 values in

Cross Section ZW

ZW Cross Sections are mainly used in the modeling of rivers. They correspond to the Tabulated River Cross Sections in SOBEK 2. They are usually calculated by external software (for
example BASELINE/WAQ2Prof) and imported into a flow schematization. Figure 4.30 shows
the editor for ZW Cross Sections. Instead of a location-level relation a ZW Cross Section has
a relation between the channel width and the waterlevel. In addition, there is a difference
between the flow width (the part of the channel that takes part in the actual flow) and the total
width (the flow width with additional storage). As a consequence, ZW Cross Sections are
always symmetrical.
ZW Cross Sections can incorporate a summer dike with additional flow and storage area
(Figure 4.30). The part of the floodplain behind the dike does not play a role in the computation
until the waterlevel exceeds the crest level of the summer dike. When a summer dike floods
the extra area is added to the cross section. To prevent the flow area from taking part in the
flow process too easily, D-Flow 1D uses a transition height (see Section 4.11) above the crest
level to ’scale’ the flow into the floodplain. When the waterlevel falls below crest level, the
extra area is gradually removed again from the cross section, modeling the water behind the
summerdike to flow back slowly into the river until the flood plain is dry again.

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Figure 4.30: Cross section editor for ZW Cross Sections

4.3.12.5

Cross Section

Cross Sections allow to specify simple geometries like:

Rectangle
Arch
Cunette
SteelCunette
Ellips
Trapezium

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Figure 4.31: Cross section editor for Trapezium

In the editing window for Cross Sections these geometries can be defined. Figure 4.31 shows
the Cross Section editor with a trapezium cross sectional profile as example. It is not possible
to model storage volume with these types of cross sections.
4.3.12.6

Working with Shared Cross Section definitions

The geometry (profile) and other parameters can be shared with different Cross Section objects in a network. Modifying a Sshared Cross Section will change the definition, and therefore
change the cross section data of all Cross Sections that refer to the Shared Cross Section
Definition.
Note: that the level-shift is not shared. It is specified for each Cross Section object individually
in the Cross Section editor (Figure 4.32).
To make an existing cross section sharable, open the Cross Section editor, choose use local
definition and press Share this definition.

Figure 4.32: Switch between Local Cross Section definition and Shared Cross Section
definition in the Cross Section editing window

Now, the cross section can be used at different locations in the network. Shared Cross Section
Definitions are listed in the Region window.
Note: Several options are available, by a right-mouse-click in the Region window, under
, on a cross section:

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Rename
Delete
Show usage. . . lists locations where this Shared Cross Section Definition is used.
Set as default. Now, the user can add a default cross section by selecting the Add Cross
Section from Shared Default Definition

in the Map / Network ribbon.

Quick fix: Place on empty branches will place the Shared Cross Section Definition on
branches which do not yet have any cross section
Import and export cross sections from/to <.csv>-file

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4.3.12.7

Figure 4.33: Example importing YZ Cross Section from <.csv>-file

The picture above shows the columns SOBEK 3 requires. An example file can be obtained by
exporting some cross sections.
By default, cross sections with the same Name will be replaced. By de-selecting Import
chainages the location of the original cross section can be left unchanged. In that case, the
column can be left empty. By default, the option Create cross section if Name was not found
in the network is activated.
The export of cross sections works the same way. The cross sections can be exported,
modified outside SOBEK and then be imported again. If a Cross Section with the same name
or id already exists, this Cross Section is updated with the values from the imported file. If a
Cross Section with the same name or ID is not present in the network, it is added as new.

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4.3.12.8

Inspect multiple cross sections in one view
It is possible to inspect multiple cross sections in one view, as follows:

unfold/expand the cross sections which you want to inspect in the Region window;
double-click on the first cross section you want to inspect; the Cross Section editor/view is
activated;

activate the Show/hide last Selected Cross sections ; and
scroll through the cross sections in the Region window by using the up/down arrow keys.
4.3.13
4.3.13.1

General functions on network objects
Esc key

4.3.13.2

Copy and paste network object

The Esc key is handy to stop the editing mode (Add ...) and switch to selection mode.

4.3.13.3

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To copy and paste network objects (weirs, pumps, extra resistance, etc.) select the object you
want to copy. Choose Copy from the context menu (right mouse-click). Select a branch you
want to paste the object into by a left-mouse-click. Right-mouse-click the branch to open the
context menu and select Paste. Move the mouse until the cursor is on the desired position
and click the left mouse-button.
Add network object

Network objects (weirs, pumps, extra resistance, etc.) can be added to the network in two
ways:

click on the appropriate button in the Map / Network ribbon. Then click on the preferred
location in the network to position the object. The object is snapped to the nearest location
on a branch.
right-mouse-click in the Region window, on the branch, and select Add object. The object
is added at zero chainage. This can be adjusted in the Properties window.
4.3.13.4

Zoom to network object

It is possible to zoom in to network objects by right-mouse-click on the object in

the Attribute Table
the Region window; for Laterals in the Project window
and select Zoom to feature.

To return to the overall view right-mouse-click on the network in Map window and select Zoom
to extend.

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Selection of multiple network objects
The simplest way is to select
high-lighted.

in the Tools ribbon and swipe the map. The selection will be

Another way is as follows:

Press the Esc key
Select the first network object by a left-click on the map
Hold the Ctrl or Shift key while selecting the next one
(the selection will be high-lighted)
While holding the Ctrl or Shift key, a left-click will de-select the network object

Now the user can delete all or modify one of the properties in the Properties window.

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Types of boundary conditions

Figure 4.34: Example of a network with nodes with or without boundary conditions

D-Flow 1D provides different types of boundary conditions:

No-flow (no boundary condition)
H boundary condition (waterlevel boundary condition, boundary condition of the first kind,
Dirichlet boundary condition)

4.4.1

Boundary conditions

H: constant waterlevel
H(t): waterlevel as a function of time

Q boundary condition (discharge boundary condition, boundary condition of the second
kind, Neumann boundary condition)

4.4

Q: constant discharge
Q(t): discharge as a function of time
Q(h): discharge-waterlevel-relation (rating curve)

In D-Flow 1D, boundary conditions are a property of a Node (Section 4.3.2.1). Discharge
boundary conditions can only be applied on Nodes on a single branch on the model boundary,
whereas waterlevel boundary conditions can be applied also on Nodes that connect multiple
branches.

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Editing boundary conditions

The boundary conditions are edited by double-clicking in the Project window. In the Central Map the boundary nodes are presented on the map and listed in a table.

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4.4.2

Figure 4.35: Boundary nodes in the Central Map

Right-mouse-clicking on one of the nodes in the table and selecting Open View ... opens an
editor. The following types of boundary conditions can be selected:

None
H(t): waterlevel time series
Q(t): discharge time series
Q(h): discharge waterlevel relation table
Q : constant discharge
H : constant waterlevel

By default, each Node (Section 4.3.2.1) is a no-flow boundary condition. This means no water
enters or leaves the model.

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Time series for boundary conditions

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To generate a time series, right-mouse-click in the Project window on the specific Boundary
Node and select Generate data in series (Figure 4.26).

Figure 4.36: Timeseries on boundary node

Properties of a Timeseries can be adjusted in the Properties window:

Extrapolation type for ..., choose:
Constant (default)
Linear
Periodic
None

Interpolation type for ...

4.4.3

Constant
Linear (default)

It is also possible to use a Timeseries which is available in the . Chapter Section 4.2.5 describes how a Timeseries can be imported and linked to a Boundary node.

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Simulation results corresponding to discharge boundary conditions

4.4.4.1

Remarks on discharge boundary conditions in D-Flow 1D

Figure 4.37: Computational grid of a simple network with a discharge boundary condition
upstream (water flows from right to left).

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4.4.4

Figure 4.38: Side-view of computed waterlevels corresponding to the model given in Figure 4.37 (water flows from left to right, discharge boundary condition upstream). The distance between Calculation points is 500 m.

A waterlevel boundary condition is applied on the first Calculation Point (see Section 4.10)
next to the Node with the boundary condition. This Calculation Point usually has the same
coordinates as the Boundary Condition Node. However, a discharge boundary condition is

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not applied on a gridpoint, but on a reach segment (see also Section 4.10) because of the
staggered grid numerical scheme (Stelling and Duinmeijer, 2003; Stelling and Verwey, 2006).
So D-Flow 1D sets a discharge boundary condition on the reach segment that is connected
with the Boundary Condition Node. The Calculation Point corresponding with the Boundary
Condition Node is not taken into account within the solution of the equation system, and
consequently no waterlevel result is assigned to this Calculation Point. As an estimation,
the result of the neighboring downstream gridpoint is copied to the Calculation Point at the
Boundary Condition Node (see Figure 4.37). This is physically not correct and has to be
taken into account in the design of the model and the analysis of simulation results:

A Node with a discharge boundary condition should not represent a gauge. Use an Ob-

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servation Point instead and extend the upstream end of the branch in such a way that the
observation point is located between two gridpoints that are considered in the solution of
the flow equations. In other words: the observation point should not be located within the
first and the second gridpoint that follow the Boundary Condition Node on a branch.
Simulation results of a SOBEK-RE model that has been imported into D-Flow 1D (or
SOBEK 2) will differ from results of the original SOBEK-RE model at nodes with discharge
boundary conditions.
The upstream end of a side-view will always show a horizontal course of the waterlevel
in case of a discharge boundary condition between the two upstream grid points (Figure 4.38). This is physically not correct in most cases.
Results related to Nodes with discharge boundary conditions should not be used to produce rating curves.
The usage of Discharge Boundary Condition Nodes as exchange items in an OpenMIcomposition can produce unexpected results (Becker and Gao, 2012).

Modelers experience the limitations of a discharge boundary condition as a weak point of DFlow 1D. Future releases of D-Flow 1D will provide an improved discharge boundary condition.
4.4.4.2

Discharge-waterlevel-relation

In case of a discharge-waterlevel-relation (rating curve, Q(h)), the discharge value is determined with the help of a waterlevel-discharge-relation-table. As input the waterlevel from the
previous time step is used.
It is also possible to model a waterlevel-discharge-relation (h(Q)). To do so, the user must
specify negative discharge values in the waterlevel-discharge-relation-table.

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Setting the initial conditions

4.5.1

Initial conditions

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4.5

Figure 4.39: Initial conditions editing in a table (below the Central Map) for branchchainage locations and the corresponding initial value

For a D-Flow 1D model

water depth or waterlevel; and
discharge

can be set as initial conditions. By double-clicking in the Project window on the initial conditions are presented (as a
separate layer) in the Central Map and in a table (Figure 4.39).
To define initial conditions with spatial variation, add locations in the table by mouse-clicking
in the Network Coverage ribbon. A location can now be added by a mouse-click on the
location in the map. The location is added to the table (Figure 4.39), in which the chainage
and value can be adjusted. Network locations can also be added by directly adding a new line
and providing branch and chainage data in the table.
As soon as a network location on a branch is defined, the default value for the schematization
is overruled for that branch by the locally defined value. When more network locations are
added to the same branch, the values are interpolated linearly between the locations and
extrapolated constant towards the nearest node, see also Figure 4.39.
The initial conditions for discharge can be specified similarly by double-clicking in the Project
window on . Positive discharge
values means water flowing in the direction of the branch, a negative value means water
flowing opposite of the defined direction.

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Initial conditions from restart
Instead of prescribing initial conditions, it is possible to start a model run from a previously
calculated model state: a restart. A restart state is a complete model state including the values of all the relevant parameters (waterlevels, velocities, discharges, positions of structures,
numerical parameters, etc.) required to reproduce exactly the same simulation results starting
from this restart state as from the original simulation that created the restart state. A model
can only restart from a previous model run for the same model. For restart options see also
Section 4.11.

Of course, the (restart)states must be available in the project. This can be achieved by selecting in the Project window and set on in the
Properties window (as in Figure 4.40).

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4.5.2

Figure 4.40: Flow model properties window: How to write restart states

This way, the state will be stored in the Project window on ,
see(as in Figure 4.40).

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Figure 4.41: States calculated in previous model run

In order to use this state, the user must select and drag the state to the in the Project window, and set on in the Properties window (as in Figure 4.40).

Figure 4.42: Flow model properties window: How to use a restart state

a previous simulation of the same model
a simulation in the same project
The only restriction is that the network has to be the same.

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4.6
4.6.1

Roughness
Introduction
The roughness of the bed is defined for the entire width of the branch. The branch can be
divided in separate Sections (roughness) with different roughness characteristics, for example
main channel (summerbed) and left and right bank (winterbed). The user is free to choose
names for the roughness-sections. An exception is the symmetrical Cross Sections ZW (??).
If this type of Cross Section is used, the roughness-sections have pre-defined names: Main,
FloodPlain1 and FloodPlain2. For each roughness-section on a branch the roughness can be
specified as

a constant value
spatially varying
a function of waterlevel or discharge.
The roughness values themselves can vary along the branch, so roughness can be allocated
for any number of locations along a branch.

4.6.2

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The roughness values per roughness-section can be edited as a separate model feature. This
has the advantage that the roughness for all locations is directly visible in one table or map.
This gives the user a good overview of the roughness in the network. The roughness is also
easier to edit.
Defining roughness

Figure 4.43: Roughness editor for a model of the Dutch part of the river Meuse. On the
left the roughness table with Branch, Chainage, Function, Roughness Type,
Value and Unit (automatically set according to the Roughness Type); on the
right the graphical representation of the roughness-table content.

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Figure 4.44: Setting of roughness-sections in the Region window

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Defining roughness is a three-step process:

1 Define the roughness-sections, e.g. main, left bank, right bank and so on. In case of Cross
Sections ZW this step can be omitted as the names are pre-defined.
2 Define the geometry of the roughness-sections in the cross-section editor (section 4.3.12,
Figure 4.27, Figure 4.28, Figure 4.30).
3 Set the roughness-type and -values in the roughness editor which is accessible by doubleclicking Roughness in the Project window. By adding locations on the branches, the
roughness can be specified varying over the network as shown in Figure 4.43.

A roughness-section is added in the Region window by a right-mouse-click on
and choosing Add Section Type (Figure 4.44). The roughness-section is added to the list and
can be renamed by a double mouse-click on the specific roughness-section or by pressing
the key “F2”.

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Figure 4.45: Cross section editor for an XYZ Cross Section with three Sections (roughness). The roughness-section ‘left bank’ is selected in the table and highlighted in purple.

For each Cross Section the roughness-sections need to be set in the cross-section editor
(section 4.3.12, Figure 4.27, Figure 4.28, Figure 4.30) in the table (Cross Section ZW: values
can be specified for “Main”, “Floodplain1” and “Floodplain2”). Fill in the Start and the End
columns with Y -values (or Y 0 -values for Cross Sections XYZ) and chose the Roughness in
the drop-down menu. The roughness-sections are visualized as blocks beneath the graphical
representation of the cross-section (Figure 4.45).
The list of roughness sections is also visible in the Project window. A double click on a specific
roughness section opens the roughness editor for this section (Figure 4.43) with a roughness
table and its graphical representation. The columns Branch and Chainage in the table define
the location in the network. With the Add Network Location tool
from the Menu bar,
locations can be added to the table by a mouse click in the map. These locations can be
moved to a precise location by adjusting the chainage value in the table. Within a branch the
roughness values are interpolated between the specified network locations. If no locations
are specified for a branch, the default value is used for the entire branch. The roughness can
be defined as

constant
a function of water level h
a function of discharge Q.

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Figure 4.46: Function table for roughness as a function of discharge and the graphical
representation of the table content

The following rouhgness parameters (Roughness Type) are available:

Chézy
Strickler ks
Strickler kn
Manning
White-Colebrook
Bos & Bijkerk

The choice of Function Type in the roughness table (in our case “FunctionOfQ” is valid for the
whole branch, so the corresponding drop-down menu is only accessable for a chainage of
0 m. In case of a constant or spatially varying roughness, the value is set in the column Value.
If the roughness depends on water level or discharge, the corresponding function has to be
specified in a function table (left mouse-click on the corresponding field in the last column
). For a branch in the Meuse model (Figure 4.43) such
of the roughness table
a function table is given with Figure 4.46. Here the roughness is defined as a function of
discharge Q for the whole branch. The first column in the function table Figure 4.46 contains
the discharge levels, the remaining columns refer to the chainage values specified in the
roughness-table. If no locations are defined for a branch, the model wide value and type are
used, visible and editable in the Properties window after selecting the roughness coverage.

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4.6.3

Import and export roughness from/to csv-file
To export roughness definitions right-mouse-click in the Project window on
and select Export. . . . Give a file name in the file selection-window that pops up. In the same
way the values for a single roughness-section can be exported as well. Import works the
same way. The roughnesses can then be modified using another application and imported
again.
Wind

Wind friction
Wind shielding

In channel systems with long stretches of narrow channels and/or large open water surfaces
shear stress induced by wind on the water surface can have an impact on the water movement. This leads to locally higher or lower waterlevels than for a situation without wind. In
D-Flow 1D there two effects of wind can be taken into account:

The wind friction depends on the wind direction and velocity. In D-Flow 1D a spatially uniform,
but temporarily varying wind velocity field can be applied. The wind field can be edited after
double-clicking in the Project window on . A
time series can be generated by a right-mouse-click on in the Project window and
choosing Generate data in series (see also Figure 4.26). Two parameters need to be set: the
wind velocity (m/s) and the wind direction (deg). The wind direction indicated the direction the
wind is coming from (e.g. 270 deg = westerly wind).

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4.7

Wind shielding is a geometrical effect; parts of a river may be in the lee and in practice feel
only part of the wind or no wind at all. Wind shielding is modelled in D-Flow 1D as a factor
which determines the fraction of the total wind field actually impacting the channel. The values
range from 1 (no shielding) to 0 (complete shielding). Wind shielding in D-Flow 1D is spatially
varying, but uniform in time.

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Figure 4.47: Wind shielding (factors) presented in the Central Map and the table for editing

The default factor can be adjusted in the Properties window when in the Project window
is selected. The wind shielding
editor (Figure 4.47) opens on double-clicking in the Project window on .
Network locations can be added to the table with the help of the Add Network Location tool
in the Network Coverage ribbon. Move the mouse to a location in the map of the wind
shielding editor and left-click. The location is added to the table as a value pair of Branch and
Chainage. Adjust the value in the table if necessary. Network locations can also be added by
adding a new line in the table.
If a network location on a branch is defined, the default value for wind shielding is overruled. When more network locations are added to the same branch, the values are interpolated linearly between the locations, or values are extrapolated constantly towards the nearest
node. The results of interpolation or extrapolation are visualized in the wind shield editor (Figure 4.47). If no wind data (friction or shielding) is specified, D-Flow 1D assumes no influence
of wind on the water flow.

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Salt water intrusion
Salt water intrusion in open water is the movement of saline water into an estuary, river or fresh
water aquifer. “Intrusion” is a geological term used for the process of liquids into hard rock.
Salt transport in estuaries and tidal rivers can be considered as transport of conservative
substance in water. The transport of salt is described by the advection-diffusion equation
for the salt concentration or the chloride concentration. In this way, density differences are
introduced that have to be accounted for in the momentum equation of the D-Flow 1D module.
The flow field as computed by the flow model will be used again in the advection-diffusion
equation of salt and the density differences due to changes in the salt concentration are used
in the momentum equation.

The process of salt water intrusion can be added to the D-Flow 1D model by selecting in the Project window, and setting Use salinity in the Properties window to True,
(Figure 4.48, see also Section 4.11). The property Use salt in calculation has been implemented to leave out the salt water intrusion processes in the flow simulation without losing the
salt related data in the schematization. However, when Use salinity is set to False, all existing
salt data in the schematization is deleted after having warned the user by a message box.

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4.8

Figure 4.48: Addition of salt in a flow model in the Properties window

When salt water intrusion processes are added to the model, the Project window shows two
new components (Figure 4.49):

Initial Conditions / initial Salinity Concentration
Dispersion / Dispersion F1 coefficient

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Figure 4.49: Project window after setting Use salinity to “True”

By double-clicking in the Project window
the initial conditions editor is opened. Similarly to other initial conditions a default value for
initial salinity concentration can be set in the Properties window when selecting in the Project window. To define local initial salinity
concentrations, add locations to the network by mouse-clicking the Add Network Location
in the Network Coverage ribbon. A location can now be added by a mouse-click on the location in the map in the initial salinity concentration editor. The location is added to the table, in
which the chainage and branch value can be adjusted. Network locations can also be added
by directly adding a new line and providing branch and chainage information in the table in
the initial salinity concentration editor.
The dispersion coefficient can be spatially uniform or varying. The dispersion coefficient can
be edited similarly to the initial salinity concentration.
By default, the dispersion coefficient is constant in time. However, there is an advanced option
where the dispersion coefficient varies in time, as introduced in Kuijper and Van Rijn (2011).
This can be activated as follows:

First, select in the Project window
choose KuijperVanRijnPrismatic as Dispersion formulation in the Properties window
and select the Estuary mouth which the algorithm will use as mouth of the estuary - a list
of boundary nodes is presented

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Then, double-click on - where Fx is F1, F3 or F4 - in the
Project window,

select the tab
and specify the F1, F3 and F4 (the same way as the Dispersion F1 coefficient). The F4

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will be used by the KuijperVanRijn algorithm.

Figure 4.50: The use of an advanced dispersion formulation like KuijperVanRijn

The use of F4 (unequal to zero) is for advanced users only. Details are given in the DFlow 1D, Technical Reference Manual. The F4-term of the dispersion coefficient is calculated
per branch. It is recommended that a branch has similar tidal characteristics and a similar
depth throughout, which can be achieved by shortening branches by placing additional nodes.
When salt water intrusion processes are taken into account in the D-Flow 1D model, salt
is also added in the Boundary (node) Data editor and the Lateral (source) Data editor. By
double-clicking on a specific boundary node in the Project window, the boundary node editor
is opened in which the user can select the tab Salinity Data. Figure 4.51 shows the resulting
screen. The user specifies a salt concentration at the boundary either as a constant or as
a function of time. For salinity concentrations as a function of time, a time series can be
generated by adding dates to the table. At tidal sea boundaries, the water will alternately flow
out of the model and into the model. The Thatcher-Harleman time lag defines a transition
period in seconds for the boundary condition when the condition changes from low tide to
high tide the model (Thatcher and Harleman, 1972; RIZA, 2005).

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Figure 4.51: Boundary node editor for salinity

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Temperature
The modelling of temperature is very similar to the modelling of salt water intrusion. The user
has to model the initial conditions and the temperature of water at boundaries and lateral
sources.

Temperature can be added to the D-Flow 1D model by selecting in the
Project window, and setting Use temperature in the Properties window to True, as in Figure 4.52.

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4.9

Figure 4.52: Addition of temperature in a flow model in the Properties window

Three temperature models are available:

Transport - default
Excess
Composite

When temperature is added to the model the is
added in the Project window. By double-clicking the Initial Conditions editor will appear in
the central window, below the map. Figure 4.53 shows the resulting screen. Modelling is the
same as modelling , described in the previous paragraph.

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Figure 4.53: Modelling initial temperature

In addition, an extra tab is added in the Boundary (node) Data editor and the Lateral (source)
Data editor. By double-clicking on a specific boundary node in the Project window, the boundary node editor is opened in which the user can select the tab . The
user specifies temperature at the boundary either as a constant or as a function of time. A time
series can be generated by adding dates to the table. The same applies for lateral sources.
The Excess temperature model requires extra specifications, in the Properties window:

Background temperature
Surface Area

The Composite temperature model requires extra specifications:

In the Properties window, the following settings:
Atmospheric Pressure
Stanton number
Dalton number
Heat Capacity

In the Project window the time-dependent Meteo Data:
Air temperature
Relative humidity
Cloudiness

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Computational grid

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D-Flow 1D uses a staggered grid for the numerical solution of the flow equations (SOBEK3_TRM,
2013). The computational grid is not part of the D-Flow 1D network, but a separate layer
which can be opened and viewed in a map by double-clicking in the Project window on
.

Figure 4.54: Generate Computational Grid window

To generate a computational grid for a network right-mouse-click in the
Project window and select Generate calculation grid locations. The grid generator window
(Figure 4.54) appears. By default, the grid is generated for the entire network. If one or
multiple Branches are selected in the computational grid view and “Selected branches” is
activated in the computational grid editor, a computational grid is generated only for selected
Branches. There are two general options for the grid generation:

Generate new calculation points. This option removes all existing calculation points. A
completely new grid is generated.
Use existing calculation points. With this option the existing calculation points are reused
for the branch where they are already present.
For the positioning of the calculation points the following options are available:

None. This option removes the grid from a branch,
Prefered length. This option defines the prefered distance between calculation points.
Special locations.

4.10

Cross Section. With this option D-Flow 1D generates also a calculation point on each
Cross Section the Network/Branch

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Lateral Sources. A grid point is generated on the location of a Lateral Source. As
the continuity equation is computed for grid points, it can be advantageous for water
balance studies or water quality modeling studies to set a grid point on Lateral Source
locations.
Structures. When a structure is present on a reach segment between calculation
points, the characteristics of the structure are used for the entire segment. If this option
is switched on, D-Flow 1D generates calculation points upstream and downstream a
structure at a defined distance from the structure to restrict the characteristics of the
structure to a specified region (note that this distance should not be too small for
stability reasons).

D-Flow 1D spreads the calculation points uniformly over the branch. If the length of the branch
is not equal to multiple the preferred distance (for example, the length of the branch is 990 m
and the preferred distance is 100 m), D-Flow 1D generates a grid which optimizes the number
of calculation points and their distance as close to the preferred distance as possible (in the
example D-Flow 1D generates calculation points with a uniform distance of 99 m instead of
nine times a distance of 100 m and once a distance of 90 m).

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With the grid generator functionality it is easy to experiment with different grids to find a suitable one which is fine enough, but not too computationally expensive. A grid can be considered to be fine enough if the simulation results do not change significantly if the grid is further
refined. A starting point for the distance between grid points is the width of the cross sections.
Keep into account that:

the distance between calculation points should not be too large to ensure sufficient accuracy,

the distance between calculation points should not be too small for stability and calculation
time. By default, the smallest possible distance in the numerical scheme is set to 10 m,
the distance between the calculation points may be non-equidistant.

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Figure 4.55: Table and map view of the computational grid (note that only waterlevel
points are shown in this view)

To visualize the computational grid double-click on in the Project window. Figure 4.55 shows the editing window of a computational grid. Note that this layer shows
only the waterlevel-points and not the velocity points of the computational grid. In the table the
Branch, the chainage, the gridpoint ID and the grid point type of waterlevel points are given.
A grid point type of zero represents a non-fixed grid point, one means fixed grid point. To
change the grid point type, select a calculation points and select Fixed gridpoint in the context
menu. The grid point type can also be changed in the table by editing the field in the Grid
point type column. Fixed calculation points are not affected when the grid is redefined and
are shown on the map in a different color. To add Calculation points use the Add Network
Location tool
map.
4.11
4.11.1

in the Network Coverage ribbon and click on the preferred locations in the

Model properties
Introduction
When a flow model in the Project window is selected, in the Properties window the modelwide settings can be specified. These settings are supplied to the calculation core at Run
model. The parameters are divided in different categories which are discussed below. The
parameters mentioned in this section are present for any D-Flow 1D model. Not all parameters are elaborated here. In addition, there are some parameters which are only used in the
Grafical User Interface.

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4.11.2

General
In this category the user can only set the Name of the flow model.

4.11.3

Initial conditions
As initial conditions the user can specify waterlevel or water depth. For both options a global
value can be specified. For lowland areas the waterlevel can be an appropriate option, for
hilly modeling areas the water depth option can be the option of choice.
The use of previously computed simulation results as initial condition (Restart) is described in
Section 4.5.2.

4.11.4.1

Model settings
Roughness for tidal flow

4.11.4

With regard to tidal / reverse flow, the user can set the following parameters:

Salt water intrusion

With regard to salt water intrusion, the user can set the following parameters:

UseSalinity,
UseSalinityInCalculation,
Dispersion formulation,

default: false
default: false
default: Constant

and under Run parameters / Model parameters:

4.11.4.2

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Use reverse roughness, default: False
Use reverse roughness in calculation, default: False

[31] DiffusionAtBoundaries,
[35] DispMaxFactor,

default: true
default: 0.45

The difference between UseSalinity and UseSalinityInCalculation is that the
first one is related to salinity data and the second one related to the flow simulation. If
UseSalinity is true and UseSalinityInCalculation is false, the simulation is run
without salt, but the salt-related data in the model are still present, like Initial Conditions
for Salinity Concentration. A next simulation can then be performed with salt without having to set all data again.

DiffusionAtBoundaries makes it possible to switch the diffusion term at boundaries
on or off. For modeling of salinity a so-called advection-diffusion equation is applied. At open
boundaries the user has the possibility to switch on or off the diffusion term. The default option
is that the diffusion is switched off at open boundaries.
For modeling of salinity SOBEK uses an explicit numerical method. This requires time step
limitations in order to ensure stability. For the dispersion term this is of the form

∆t · D
≤ LD
2∆xi 2

(4.1)

with the dispersion coefficient D and LD the dispersion limit. ∆xi is the mesh size (of node i)
and ∆t denotes the time step. In SOBEK 3 a value of 0.45 is applied for LD , which is slightly
smaller than the theoretical maximum of 0.5. It is advised not to change this model parameter.

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It is foreseen that in a next release of SOBEK 3 this model parameter will be removed, since
an implicit scheme will be implemented.
4.11.5

Output parameters
In this category the user can set the Model output time step. The user can specify which
type(s) of output in Section 4.12.

4.11.6
4.11.6.1

Run parameters
Simulation period and timestep
The user specifies:

Start time:

4.11.6.2

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Default: yesterday, 00:00:00h.
Start point in time of simulation period in date format [yyyy-mm-dd hh:mm:ss].
Time step:
Default: 0 d, 01:00:00h.
Spatial discretization for the simulation [dd hh:mm:ss].
Stop time:
Default: today, 00:00:00h.
End of the simulation period in date format [yyyy-mm-dd hh:mm:ss].
Restart and save State

In this category the user writes and uses states to restart a simulation:

Use restart: use the State stored in the .
The user will have to copy or link the State from a previous model run (from to )
Write restart: write the state and store in the
Use save state time range: copy the Start time from the saved state
4.11.6.3

Model parameters

Here, the following numerical parameters can be specified. Some of these are explained in
detail in the following sections.

[1] AccelerationTermFactor:
Factor on 1D acceleration term

[2] AccurateVersusSpeed:

∂U
,
∂t

Default: 1.0

can vary between 0.0 and 1.0.

Default: 3

Accuracy factor

[3] CourantNumber: Maximum Courant number. 1.0
[5] EpsilonValueVolume:
[6]
[8]
[9]
[11]
[12]
[13]

Convergence criterion for water volume balance.
EpsilonValueWaterDepth:
Convergence criterion for water depth.
MaxIterations:
Maximum number of iterations.
MinimumLength:
Minimum branch segment length.
MinimumSurfaceinNode:
Minimum surface in node.
RelaxationFactor:
Relaxation factor.
Rho:
Density of freshwater.

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Default: 0.0001 m3
Default: 0.0001 m
Default: 8
Default: 1.0 m
Default: 0.1 m2
Default: 1.0

Default: 1000 kg m−3

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[14] StructureInertiaDampingFactor:

Default: 1.0

Structure inertia damping factor.

[15] Theta:

Default: 1

Theta-value.

[16] ThresholdValueFlooding:

[18]
[19]
[24]
[25]

Parameters for debugging a model:

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[26] Debug
[29] DebugTime

Default: 0.001 m
Default: 0
Default: 0.0
Default: true
Default: 0.5 m

[17]

Default: 0.01 m

Threshold water depth for flooding of channels.
ThresholdValueFloodingFLS:
Threshold water depth for flooding of land surface.
UseTimeStepReducerStructures:
Use timestep reduction on structures (0=false, 1=true).
ExtraResistanceGeneralStructure:
Extra resistance for general structure.
NoNegativeQlatWhenThereIsNoWater:
Limit lateral outflow to the water available in the channel.
TransitionHeightSD:
Transition height for summerdikes.

default: false

Numerical parameters, read more in Section 4.11.6.11

[32] Iadvec1D:

Default: 2

Advection Type in 1-dimensional flow.
[33] Limtyphu1D:
Limiter type for estimating flow area at velocity point in 1D flow.

Default: 1

4.11.6.4

Structure Inertia Damping Factor

The structure equations contain an inertia term. This inertia term acts as a kind of numerical
damping. This is done to avoid numerical oscillations in case of unsteady flow conditions. The
numerical parameter ’factor for structure dynamics’ is a factor applied to this inertia term. The
following default value is suggested:

[44] StructureInertiaDampingFactor

Default: 1.0

Note: that for steady flow conditions the inertia term is set to zero, because in this case the
Structure Inertia Damping Factor is not taken into account.
The structure inertia damping factor is applied for the River weir, the Advanced weir, the General structure and the Database structure both as single structure or member of a composite
structure. In the linearization of the concerning structure equation a term

∂U
∂t

(4.2)

is added, where

α
U
t

structure inertia damping factor [-];
flow velocity [m/s]; and
computational time [s].

The structure inertia damping factor can be used for avoiding instabilities during computation.

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4.11.6.5

Extra resistance for general structure
A default value is defined for the so called extra resistance coefficient of the General structure
type, both as a single structure and as a member of a structure:
Default: 0.0

[19] ExtraResistanceGeneralStructure

This default value can be overruled for each individual General structure type. The so called
extra resistance refers to a bed shear stress force, that is accounted for in the impuls balance,
that is solved in case of drowned gate flow or drowned weir flow. The bed shear stress force
reads

ρ2 LW2 U22

g
C2

(4.3)

λρ2 W2 U22
where:

.
4.11.6.6

= Lg/C 2 , extra resistance coefficient;

(4.4)

length of hydraulic jump behind the structure in [m];
acceleration due to gravity in [m2 s−1 ];
Chézy coefficient in [m1/2 /s];
density of water in hydraulic jump in [kg m−3 ];
downstream flow velocity in [m s−1 ]; and
downstream structure width in [m]

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λ
L
g
C
ρ2
U
W2

Summerdike

For summerdikes, the user can set the transition height.

[52] TransitionHeightSD

Default 0.5 m

See also Section 4.3.12.
4.11.6.7

Advanced options

The user can set the following advanced parameters:

[9] MinimumLength:

Minimum branch segment length.
[8] MaxIterations:
Maximum number of iterations.

[24] NoNegativeQlatWhenThereIsNoWater:

Default: 1.0 m
Default: 8
Default: true

Limit lateral outflow to the water available in the channel.
4.11.6.8

Volumes based on waterlevels or discharges
In SOBEK there are two options for computing the volume of a calculation point (or reach
segment) at a specific point-in-time, viz:

Volumes based on waterlevels (parameter value is 0)
Volumes based on discharges (parameter value is 1)
If the option ’Volumes based on waterlevels’ is selected, this means that the volume at each
calculation point (or each segment) follows from the computed waterlevel and its correspond-

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ing cross sectional cross section. If the option ’Volumes based on discharges’ is selected, this
means that the volume at each calculation point (or reach segment) is the summation of its
volume in the previous time-step and the resulting net inflow during the computational timestep. In Water Quality computations especially use is made of volumes and discharges. By
choosing the option ’Volumes computed based on discharges’ a more coherent set of volumes
and discharges is obtained, than in case the option ’Volumes computed based on waterlevels’
is selected.
4.11.6.9

Reduction of timestep on large lateral flow

4.11.6.10

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In case the user defines a value for ’Reduction of time step on large lateral inflow’ equal
to 1, the computational time step will be reduced in such a way that the maximum lateral
inflow volume is not more than the volume stored in the corresponding computational point.
In addition the user can define a minimum time step for the ’reduction of time step on large
lateral inflow’ procedure by defining a value for the parameter ’minimum time step in time
step reduction on large lateral flow’. Whether the ’Time step reduction on large inflow’ is
true or false, for lateral outflow always the above procedure applying the actual value for the
parameter ’minimum time step in time step reduction on large lateral flow’ is used.
Use timestep reduction on structure

In case the user defines a value for [18] UseTimeStepReducerStructures equal
to 1, at the point-in-time of the wetting of the crest of a structure (i.e. for weirs and orifices
only) a time step reduction will be applied during a time-span equal to two times the user
defined time step. This functionality was implemented to avoid oscillation in specific Urban
schematisations with sharp inflow hydrographs, it can be applied in Rural schematisations as
well. Unnecessary use of this option might result in a longer computational time needed.
4.11.6.11

Parameter set for lowland rivers

Three numerical parameters are specially suited for lowland rivers with strong contraction
and/or expansion.

[32] Iadvec1D:

Default: 2
This parameter determines the way the advection term in the De Saint Venant equation is
implemented. Possible values are:
1 Conservation of Momentum
2 Weighted Average of Conservation of Momentum and Conservation of Energy in Contraction and Expansion
3 Weighted Average of Conservation of Momentum and Conservation of Energy in Contraction Only
4 Weighted Average of Conservation of Momentum and Conservation of Energy in Expansion Only
5 Conservation of Energy

[33] Limtyphu1D:

Default: 1
This parameter determines the estimation of the waterlevel at the velocity points to calculate the continuity equation. Possible values are:
1 Upwind
2 Central in Cross-sections
3 Central in Water levels
Possible values are:
1 Total area

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2 Flow area with account for storage sink term
3 Flow area
4.11.7

Default bed roughness
The (factory) defaults for the roughness type and value are:

Roughness type
Default roughness value

Default: Chézy
Default for Chézy: 45 m1/2 /s

The user can overrule this default value by defining the roughness locally, see Section 4.6.
The options for roughness types and their corresponding default values are given in table 4.1.

Roughness type

4.12

Output

Default value
45
0.03
33
0.2
33.8
0.2

Unit

m1/2 /s
s/m1/3
m1/3 /s
m
m

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Chézy, C
Manning, Mn
Strickler, Ks
Strickler, Kn
Bos & Bijkerk, γ
White & Colebrook, Kn

Table 4.1: Options for roughness types and default values

Before running a simulation, the user can set which output is required by selecting
in the Project window under . The Properties window then looks like Figure 4.56.

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Figure 4.56: Set output in the Properties window

The list in the Properties window contains all possible parameters for which simulation results
can be generated. For each parameter, the user can choose between the following types of
output:

Maximum: the maximum value during the output timestep
Minimum: the minimum value during the output timestep
Average: the average value during the output timestep
Current: the values at the precise timestep

In addition, two output timesteps can be set:

Gridpoints: for gridpoints and reach segments
Structures: for structures, lateral sources, retentions and observation points
The user can choose the following parameters on Grid points:

Water depth
Water level
Water volume
Total area
Total width
Salt concentration
Density
Lateral at nodes
Lateral Discharge from 2d to 1d

For Reach segments, the following parameters are available:

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Discharge
Velocity
Flow area
Hydraulic radius
Salt dispersion
Conveyance
Chézy values
Water level gradient
Froude number
Subsection parameters

Discharge (l)
Water level (l)

For Lateral sources, the following parameters are available:

For Observation points, the following parameters are available:
Water level (op)
Water depth (op)
Discharge (op)
Velocity (op)
Salt concentration (op)
Salt disperion (op)
Water volume (op)

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For Pumps, the following parameters are available:

All output (p)

For Retentions, the following parameters are available:

Water level (rt)
Volume (rt)

For Simulation info, the following parameters are available:

Negative depth
Number of iterations
Timestep estimation
Waterbalance1D_TotalVolume and many more ...

For Structures, the following parameters are available:

Discharge (s)
Velocity (s)
Flow area (s)
Crest level (s)
Crest width (s)
Gate lower edge level (s)
Opening height (s)
Valve opening (s)
Water level up (s)
Water level down (s)

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Head difference (s)
Pressure difference (s)
Water level at crest (s)
For Waq output, the following parameters are available:

Write hyd file
4.13

Validation

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As a final step in the modeling process, the user can activate the validation tool, by a rightmouse-click in the Project window on and selecting Validate.... A validation
report is presented in the central window (Figure 4.57). This example shows the validation

Figure 4.57: Validation Report: example

report for a simple flow model where the computational grid has not yet been defined. The
user can simply double-click to open the appropriate editor. This way the report serves as a
todo-list.
The validation tool checks all that is required for a model run. In other words: a validated
model will run!
4.14

Merge Models

It is possible to combine models of different coordinate systems into one model with the merge
tool. The merge model is currently applicable for both D-Flow 1D and for integrated models
consisting of a combination of D-Flow 1D and D-RTC. The workflow for combining two projects
is shown in Figure 4.58. It consists of four steps:
1 Import the model of the Source project in the Destination project (Explained in section 4.2.1)
2 In case the (imported) Source model is defined in a different coordinate system, one of
the models needs to be transformed (Instructions below)
3 Merge the model of the Destination project with the (imported) Source model (Instructions
below)
4 Delete the Source model (Right-mouse-click the model and select Delete).
Having a project containing two models (D-Flow 1D or integrated) one has to decide which of
those will serve as destination model and which will be the source model. The destination
model will keep all it’s global settings (e.g. timestep, outputsettings, etc.), while of the source
model only local settings are being copied into the new model (e.g. the netwerk, boundary
condition, roughness, etc.).

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Figure 4.58: Merge model workflow

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Start the model merge by a right-mouse-click on the destination model. Select Merge with...
and the source model. A validation report will now open in the central window, showing any
warnings and errors. If no errors occur in the report, the merge can be finished by clicking the
Merge button at the bottom of the validation window.
A couple of remarks and common mistakes:

All spatial objects in your model, like network, basin or waterbody are associated with and

defined in a coordinate system. You need to set the coordinate system for both networks.
Select your network in the Project window and change the in the
Properties window.
In case the two networks are defined in different coordinate systems, you need to transform (the coordinates of) one of both networks. You can do so by a right-mouse-click on
the intended in the Project window, select Convert to Coordinate System...
and specify the coordinate system of the other network.
The Merge button only appears if no errors occur. Correct your destination and/or source
model until no errors occur.
Be aware that the validation report is not automatically closed after merging. Do not press
the merge button twice.
Global variables of the source model are omitted. This also applies for the global initial
conditions and salinity.
Network features that have a name that exists in both the destination and the source
model, will have the feature of the source model renamed to [source model name]_[network
feature name]
It is not possible to merge two D-RTC models. As these models are closely related to the
flow model they can only be merged as an integrated model.

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5 Module D-Flow 1D: Simulation and model output
When the schematization is complete, the model is ready for a simulation. A simulation is
run by right-mouse clicking the flow model in the Project window and selecting run model.
Alternatively, by clicking one of the buttons in the Home ribbon:

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During the simulation a progress bar appears and simulation messages are shown in the
Messages window. A logfile (Run report) is added to the model output in the Project window,
which can also be exported. In this report all the schematization and simulation messages are
logged. During the simulation, output is generated by the model. Besides physical quantities
related to flow, such as velocity or water level, also simulation information is provided which
contains information on the accuracy and numerical behaviour of the simulation. The output
is stored in coverages, which are added to the model output in the Project window, see also
Figure 5.1.
In addition, States are stored for later use as Restart. Of course, the user has to request to
Write restart in the Properties window before running the model.
If the network, computational grid or model parameters change, the output is no longer valid
and is deleted. Output in a model is therefore always consistent with the model.

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Figure 5.1: Output in the Project window

5.1

Simulation information

The simulation information is divided in spatial and non-spatial information. The spatial information is generated in output coverages and can be visualized in maps, graphs and tables,
just like other output parameters such as waterlevels. The non-spatial information is saved in
a textfile and can be found in the Project window under model output.
Non-spatial information consists of

Version information of the plug-ins (modules) used
Total calculation time
List of numerical parameters and the values used
Smallest and largest timestep
Water balance components
Balance error
Initial conditions

This information can be used to assess the model performance and accuracy. It can also be
used to solve problems in the schematization.
The spatial simulation information consists of

negative depth
Timestep estimation
Number of iterations

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This information can be used to remove errors from the schematization or improve the performance of the model.
Results in the Map

By double-clicking a specific output parameter in the Project window the results for that parameter are presented (as a separate layer) in the map with the network, see also Figure 5.2.
The map shows for all available calculation points (for that parameter) the value of the specific output parameter for a specific timestep which can be adjusted in the Time Navigator
window. By sliding the red bar in the Time Navigator, the user can navigate through the
results in time. For each map there is a separate Time Navigator, so that it is possible to
view different timeslices of several parameters simultaneously by docking the map windows
next to each other.

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5.2

Figure 5.2: Map results of discharge

For each map it is possible to add shapefiles as background map and display or hide (parts
of) the network by (de)selecting the appropriate layers in the Map window. The Map window
can also be used to change the symbols in the map for each layer. By double-clicking on a
layer the Layer properties editor opens in which colorscales, symbol sizes, legend classes
and symbol style can be adjusted, Figure 5.3.

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Figure 5.3: Layer properties editor

Alternatively, a map can be customised by adding a new map. A new map may be opened by
right-mouse clicking on in the Project window and selecting New item and Map.
Parameters can be dragged from the Project window into the map. In this way maps can
be customised by the user. It is possible to combine several parameters from one model, or
parameters from different models, add shapefiles, show (parts of) the network etc. A resulting
map with both water level and discharge is shown in Figure 5.4.

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Figure 5.4: Customised map

5.3

Results in a Graph

Simulation results can also be shown in graphs. By double-clicking on an output parameter
it will be presented in the map. In the map one or more calculation points can be selected.
in the Menu bar, Figure 5.5 appears. The user can now select one or more
By clicking
parameters, which are then displayed in a graph, Figure 5.6.

Figure 5.5: Select parameter for graphical representation

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Figure 5.6: Time results of water level for 3 locations along the branch

5.4

Results in a Table

Next to graphs and maps are tables with the actual values of the parameters shown. For map
representations of results, the table shows all locations for one timestep, see also Figure 5.2.
For graphical representations the table shows the selected locations and parameters for the
entire simulation period, see also Figure 5.6.
5.5

Sideviews

To view simulation results along branches a sideview can be opened. First, the user needs to
specify a route.
5.5.1

Routes

In the map with the network, the user can specify a route by selecting
ribbon. A new (empty) route will be added
can be stored.

in the Network

in the Network window - several routes

Also, the
button is activated. By clicking in the map network locations can be
added to the route. The first location marks the starting point of the route, each click on the
map marks either an intermediate point along the route or the end point (in case that network
location was the last one added). The route can be finalized by pressing Esc. The routes can
be altered by moving the network locations by pressing the move-features button
in the Edit ribbon and moving the network locations along a route. At any time new network
locations can be added to a selected route by clicking on

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network locations are always added to the route, it is not possible to add a network location
halfway. It is possible to add a network location and then move the locations according to
the users wishes. Each route has a chainage starting from 0 at the starting network location.
Figure 5.7 shows an example with three network routes.
Intermediate points can be used when there are more options to connect two locations. Without using intermediate locations SOBEK will choose the shortest connection between two
locations as route. By adding intermediate locations, the user can specify alternative routes,
see Figure 5.8.
By right-mouse-click on the route in the Network window, the user can:

Open or Open with ... to view the route in the map or in Side View (see next paragraph)
Zoom to feature
Rename
Delete or
inspect Properties

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Figure 5.7: Example of 3 network routes shown in the network with different colours

Figure 5.8: Example of the use of intermediate locations to specify routes

5.5.2

Results in Sideview
The user can select a route in the Region window and open a sideview by a mouse-click
on
in the An... ribbon. A sideview always shows the waterlevels, structures and cross
sections. The user can add all available output parameters (from any model run with the same

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network route) and the computational grid, the initial conditions and wind. In this way several
parameters can be viewed simultaneously, see Figure 5.9 for an example with waterlevel and
discharge. Using the Time Navigator, the user can navigate through the results in time.

Figure 5.9: Example of sideview with Time Navigator

5.6

Export

Output data can be exported by by right-mouse clicking one of the model output parameters
in the Project window and selecting export.... The data can be exported in two manners:

Coverage file exporter (NetCDF-format)
FEWS-PI Longitudinal Profiles (FEWS-PI-format)
5.7

Case analysis

Simulation results can be analysed with the Case Analysis (tool) View. This can be activated
by clicking

in the Tools ribbon.

The Case Analysis window pops up (Figure 5.10).

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Figure 5.10: Example of Case analysis

The user can select one of the available results and one of the following Operation(s):

Mean, resulting in the mean value of the simulation period
Min, resulting in the minimum value of the simulation period
Max, resulting in the maximum value of the simulation period

For the following Operations the user must select a second result or initial conditions:

Add
Substract
Abs(olute) Difference

Figure 5.10 shows the result of a Substraction.

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6 Module D-Flow 1D: Morphology and Sediment Transport
Introduction
Morphodynamic processes and sediment transport can be simulated with SOBEK 3 as part of
the D-Flow 1D module. At the moment Delta Shell (as User Interface) has only limited support
for morphology: which means that most pre- and post-processing must be done outside Delta
Shell or with the help of Python-scripting.
Morphology is activated in the Properties window of , see Figure 6.1. The input
files must be generated separately, as described in Section 6.2. Morphological output cannot
be inspected with Delta Shell, but other tools are available, as described in Section 6.3.

A morphodynamic run can be activated in the Properties window after selecting ,
as depicted in Figure 6.1.

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6.1

Figure 6.1: How to simulate morfology together with a D-Flow 1D simulation

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6.2

Input files
Two input files are minimally required for a simulation:

The sediment input file (<∗.sed>) contains the characteristics of all sediment fractions.
The morphological input file (<∗.mor>) contains additional information necessary for a
morphodynamic run.
Users of D-Flow 1D are familiar with two versions of these files: with or without keywords. DFlow 1D uses the version with keywords. Besides the <∗.sed> and <∗.mor> file SOBEK 3
might require the following files:

The sediment layer file (<∗.sdb>) contains information about the thickness of a sediment
layer.

The sediment diameter file (<∗.d50>) can be used for spatially varying sediment diame-

ters.

The sediment transport and morphology boundary condition file (<∗.bcm>).
The sediment transport file (<∗.tra>).
The nodal relation file (<∗.nrd>) is used to define the function governing the sediment

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distribution on nodal points with two or more outflowing branches (bifurcations, trifurcations,...) and any number of inflowing branches.
A table file (<∗.tbl>) can be used for additional control over the sediment distribution at
bifurcations.
The <∗.sed> and <∗.mor> files can be generated with D-Flow 1D and/or a regular text
editor. The details are described in Appendix Section D.1.
Restrictions:
SOBEK 3 does not yet support fixed layer modelling
SOBEK 3 does not yet support multiple sediment fractions (graded sediment)
Before activating a model run, the files must be placed in the directory: <∗.dsproj_data>.
The specific path can be specified in the Properties window (see Figure 6.1).
6.3

Output files

The output file () will be placed in the (<∗.dsproj_data/water_flow_1d/output>)
directory. This file can be inspected or processed with tools that can handle <∗.his> files,
like ODS view or Python Scripting. There are also MatLab functions freely available from the
open repository Open Earth (www.openearth.eu).
6.4

Scripting support

Delta Shell allows the user to extend the functionality of the modelling suite via Python Scripting. This applies to Morphology and Sediment Transport as well. SOBEK 3 (since version
3.3) comes with several scripts that extend the functionality. The following paragraphs show
several examples.

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6.4.1

Generating input files and working with spatially varying input
The input files for spatially varying input (<∗.d50> and <∗.sdb>) are generally difficult — if
not impossible — to generate outside Delta Shell. To help with the setup of a morphological
simulation use the class. The following example shows how to quickly
setup morphological files for a fictitious model.
from SobekMorphology import MorSetup
# Create a Sobek morphology helper class
SM = MorSetup()
#region: Quick setup
# This region shows how to quickly setup spatially varying
# input for morphology. By default the sediment thickness
# is 10 m and the mean sediment diameter is 0.014 m.

6.4.2

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# Create input files for morphology
SM.create_input_files()
#endregion

# Change the default d50 sediment diameter of branch ’Channel1’ to 8 mm.
SM.branch["ChannelName1"].set_uniform_d50(0.08)

Dumping and dredging

In reality river managers intervene in the natural system in several ways. Dredging — the
removal of sediment from the river bed — is a common channel maintenance intervention.
This might be coupled with subsequent dumping, i.e. the reallocation of the dredged sediment
to other parts of the river. Dumping and dredging is not (yet) supported in the computational
core, in contrast with D-Flow 1D. Alternatively, this functionality is offered via Python scripting
via the class. Delta Shell comes with several examples of how to
work with Dredging and Dumping.
The output file () will be placed in the directory: <∗.dsproj_data/water_flow_1d/output>.
This file can be inspected or processed as any SOBEK history (<∗.his>) file.

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7 Module D-Flow 1D: 1D2D-coupled modelling to D-Flow Flexible
Mesh
7.1

Introduction
The one dimensional modelling of the module D-Flow 1D can be combined with the two dimensional modelling suite D-Flow FM to achieve 1D2D-coupled modelling. The developed
features are mainly aimed at overland flow or river flood modelling.

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The applied coupling is a horizontal lateral coupling, which implies that the direction of the
flooding is perpendicular to the flow direction of the 1D model. Strict model separation is
applied as shown in Figure 7.1.

Figure 7.1: Principle of the horizontal 1D-2D coupling in a top view and a side view. In
brown the 1D model is schematised. In black the 2D grid is shown.

In contrast to the vertical coupling, where the 1D and 2D model are placed on top of each
other (for example the Overland Flow Module of SOBEK 2), the horizontal coupling reduces
the double water storage. It also implies a separated handling of the left and the right embankments of the 1D model.
7.1.1

Principle of embankments in a 1D2D model

Due the strong separation of the models, the interface between the models becomes one of
the import elements of the 1D2D modelling. For a typical river simulation (as also shown in
Figure 7.1) the interface between both models will be the river embankments. These embankments need to be created by the modeller in the integrated model with the use of any of the
methods described in Section 7.3.
The embankments are used in multiple steps within the creation of a 1D2D-coupled model.
As the boundary of the 2D model they are used in the creation of the 2D grid (written in
Section 7.4). Furthermore they also include a variable crest height which is used by the overtopping equations to initiate the flooding and compute the overtopping discharge (described
in Section 7.1.2).
7.1.2

Principle of the embankment overtopping equations
The discharge from the 1D to the 2D grid is calculated as a function of the water levels of the
1D cell, the 2D cell and the height of the embankment on the intersection with the 1D2D-link.

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q1D2D = f (ζ1D , ζ2D , ζCrest , crest geometry)
For the computing of the discharge weir formulations are applied. Different states of the weir
can be distinguished based on the water level in the 1D and the 2D domain. When the water
levels on both side are higher than the energy height over the embankment (ζ1D and ζ2D >
zs + u2s /(2g)) the weir is called a drowned or submerged weir and Equation (7.1) is applied.

q1D2D = ce cw ζ1D − zs − u2s /(2g)

p
2g(ζ1D − ζ2D ) .

(7.1)

For lower water levels the equation for free flow ( ζ1D or ζ2D < zs +u2s /(2g) ) is applied. The
water level difference in this Equation (7.1) changes to ζ1D −ζCrest resulting in Equation (7.2).

p
2g(ζ1D − ζCrest ) .

(7.2)

q1D2D = ce cw ζ1D − zs − u2s /(2g)

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The above equations are written for the highest water levels in the 1D network. When water
flows from 2D to 1D the ζ1D and ζ2D are interchanged.

Figure 7.2: The variables which control the flow over the interface between the 1D and
the 2D model

7.2

Integrated 1D2D model

The coupled 1D2D-integrated model is automatically available as workflow when the models ‘Flow 1D model’ and ‘Flow Flexible Mesh Model’ are added to the project as shown in
Figure 7.3.

Figure 7.3: The workflow for the integrated 1D2D model

When starting a new model in your project as described in Section 3.2, the preset ‘1D-2D
Integrated Model’ can be applied to directly create the model shown in Figure 7.3.
A D-Flow 1D model can also be extended with the 2D-module later on by using the ‘Add’
button shown in Figure 7.3 and selecting the ‘Flow Flexible Mesh Model’. If your project is

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not yet an integrated model, this can be achieved by right clicking your project in the Project
window and selecting the option ‘Turn into or move to integrated model’.
Selecting the Workflow ‘(FlowFM + Flow1D)’ will also allow the user to modify the number of
iterations of the 1D2D-coupling. In the properties window the options ‘Max. Iterations’ and
‘Max. Error’ can be adapted.
7.3

Creation of embankments

Different approaches have been designed for the creation of the embankments. They can
be automatically generated based on the existing 1D-network (Section 7.3.1) or they can be
imported based on GIS data (Section 7.3.2). After creation or import of the embankments
simple changes can be done within the Deltashell editor. Those changes are described in the
remaining sections.
The embankments are stored file-based and can be adjusted manually in the Project window.
Automatic generation

The automatic generation can be started by clicking the icon ’Generate banks for selected
channels’ on the ribbon Map | FM Region (see Figure 7.4). When starting the wizard with no
channels selected, it is applied on all channels of the 1D model as shown in the title of the
pop-up window.

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7.3.1

Figure 7.4: Generate embankments wizard

The window shown in Figure 7.4 shows two options for the embankment generation.
The option Cross-section based uses the available cross sections. It uses the outer points
of all cross sections on the channel and draws a line in between based on the geometry of
the 1D channel (Figure 7.5). It also uses the Z-value of the outer points as the overtopping
height of the embankment. This method is applicable on both ZW- and YZ-crosssections. The
former will result in symmetric banks on both sides of the channel, while the latter will create
asymmetric banks based on the profile and the thalweg.
The second option Constant distance to branch only uses the channel geometry and the value

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given by the user. It creates the embankments with a constant distance to the branch resulting
in a total width between the left and right embankments of double the given value.

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Other options in the window allow for generating of the banks on only the left or right side of
the channel (looking in downstream direction) and for the performing of an automatic merge.
This last feature is required when banks for multiple channels are created. By defaults these
are handled as individual banks. By using the automatic merge they are combined. The
merge feature can also be used individually as described in Section 7.3.3.

Figure 7.5: Embankments created with automatic generation

7.3.2

Import from GIS

Embankments can be imported from GIS. This is done in two phases and has some specific
requirements of the imported files.
The import wizard can be started by browsing in the Project window to the area of the Flexible
Mesh model. For a default integrated model this is located within Integrated Model | Region |
Area. Right clicking area shows the import wizard.
At first the Flood banks are imported. This is a polyline shapefile.

As a second step the Flood bank heights are imported. These are point shapefiles with a
column “POINT_Z” in which height information is stored. The points of the shapefile have to
be on the exact location of the vertices of the earlier imported flood banks.
7.3.3

Merging of embankments

For the automatic generation of the 2D grid it is necessary for the flood banks to be merged.
This can be achieved by either automatically performing the merge after the automatic generation (Section 7.3.1) or merging banks manually afterwards.
This manual merge can be started by selecting two banks, right clicking in the map view and
selecting the option ’Merge floodbanks’ (Figure 7.6) (or selecting it in the ribbon Map | FM
Region). The algorithm will find which sides of the selected lines are closest together and will
merge those to a new embankment line.

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7.3.4

Figure 7.6: Merging of two embankments

Draw embankments and changing geometry of existing embankments

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It is also possible to draw the embankments by hand and to change existing embankments by
adjusting the geometry points. Several buttons on the ribbon can be used for this, shown in
Figure 7.7.
To apply, first select the embankment. Green squares will appear (the geometry points of the
embankment), which can be moved, removed or added.

Figure 7.7: Change geometry of an embankment

7.3.5

Inspecting the height of embankments

The Z-values can be inspected by double clicking on the embankment. A new tab will open in
which a top-view of the selected bank is shown as well as a table including the Z-values. The
new tab also has the option to change the view mode to ‘Length-Z’ as shown in Figure 7.8.

Figure 7.8: Sideview of an embankment

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7.4

Grid generation
The 2D grid is bound to several requirements in order to generate a correct coupling: it is
required to have the grid directly connected to the embankments and it needs to have a direct
(one-on-one) relation to the 1D computational grid. For those reasons it is recommended to
use the automatic grid generation.
Automatic generation based on embankments
Before starting the automatic grid generator both the embankments and the 1D computational
grid need to be ready. In the area where the grid will be created, the embankment is not
allowed to have gaps.

The grid generation can be started by using the button ‘Generate grid based on banks’ on the
ribbon Map | FM Region as shown in Figure 7.9. This selects a tool for the drawing of the
outer boundaries of the 2D grid. In the figure an example of a correct boundary is given. It
crosses the 1D network an even number of times and all embankments on this part of the 1D
network are joined to one left bank and one right bank. In order to finish the drawing of the
outer boundaries double click when placing the last point.

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7.4.1

This opens a new window which requires two inputs for the setting of the support points. The
support points are points generated on the previously drawn (outer boundary) line which will
be used for the triangulation of the 2D grid.

Support point distance. This is the preferable size of the 2D grid cells on the outer boundary of the 2D grid. In most cases this should be similar to the 1D grid resolution.

Minimum support point distance. At the embankment the support points are automatically
generated based on the 1D grid. In sharp bends this can result in support points very
close to each other. If the distance between two points is closer than the given minimum
value, one of the points will be removed.
After finishing the settings, the grid generator will start. The RGFGRID software will automatically generate grids in all selected polygons.

Figure 7.9: Automatic grid generation. The button is encircled in the top left, the outer
boundary of the grid is drawn in the map view on the right and the final window
‘Generate grid’ is shown on the left

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7.4.2

Grid deletion, modification and manual grid generation
The grid can be deleted, modified or manually created. Although these use features of the
RGFGRID software, which are described in more detail in the manual of RGFGRID (RGFGRID UM, 2016), simple applications for the use in 1D2D-modelling are described below.
The RGFGRID editor can be opened by double clicking Grid in the D-Flow FM project in the
Project window.

7.4.2.1

Grid deletion

Operations > Delete > Grid
File > Save Project
Close RGFGRID
Delete one, or a part of a grid:

7.5

Edit > Polygons > New
Draw the polygon around the grid to be deleted
Operations > Delete > Grid
File > Save Project
Close RGFGRID

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Delete the entire grid:

Simulation output

As shown in Figure 7.10, the 1D2D model has output on the 1D-network the 2D-grid and on
the links in between.

Figure 7.10: Different output types within a 1D2D-model

The method to select the output on the 1D-network can be found in Section 4.12. The discharge from 2D to 1D is only available as the total sum of all links connected the selected 1D
cell. This is named ‘lateral discharge from 2d to 1d’.
The method to visualise the result on the 2D grid are described in the manual of D-Flow FM.
On the 1D2D-links only information for debug purpose is available at this moment. Of interest to the user is the option ‘1d2d_crest_level’ which shows the crest level selected for the
selected link. The specific discharge over the link cannot be shown.

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References
Bailard, J. A., 1981. “An Energetics Total Load Sediment Transport Model for Plane Sloping
Beaches.” Journal of Geophysical Research 86 (C11): 10938–10954.
Becker, B. and Q. Gao, 2012. “Multiple model coupling through OpenMI.” Deltares-memo No.
1205954-003-ZWS-0006.
Gaeuman, D., E. Andrews, A. Krause and W. Smith, 2009. “Predicting fractional bed load
transport rates: Application of the Wilcock-Crowe equations to a regulated gravel bed river.”
Water Resources Research 45.
Grasmeijer, B. and L. Van Rijn, 1998. “Breaker bar formation and migration.” Coastal Engineering pages 2750–2758. Virginia, USA.

Isobe, M. and K. Horikawa, 1982. “Study on water particle velocities of shoaling and breaking
waves.” Coastal Engineering in Japan 25: 109–123.

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Kuijper, C. and L. van Rijn, 2011. “Analytical and Numerical Analysis of Tides and Salinities
in Estuaries; Part II: Salinity Distributions in Prismatic and Convergent Tidal Channels.”
Ocean Dynamics 61 (11): 1743:1765.
Nipius, K. G., 1998. Transverse transport modelling using Bailard applied to Grevelingenmouth delta. Delft University of Technology, Delft, The Netherlands. M.Sc. thesis, in
Dutch (Dwarstransportmodellering m.b.v. Bailard toegepast op de Voordelta Grevelingenmonding).
RGFGRID UM, 2016. Delft3D-RGFGRID User Manual. Deltares, 5.00 ed.
Rienecker, M. M. and J. D. Fenton, 1981. “A Fourier approximation method for steady water
waves.” Journal of Fluid Mechanics 104: 119–137.
Rijn, L. C. van, 1984a. “Sediment transport, Part I: bed load transport.” Journal of Hydraulic
Engineering 110 (10): 1431–1456.
Rijn, L. C. van, 1984b. “Sediment transport, Part II: suspended load transport.” Journal of
Hydraulic Engineering 110 (11): 1613–1640.
Rijn, L. C. van, 1984c. “Sediment transport, Part III: bed form and alluvial roughness.” Journal
of Hydraulic Engineering 110 (12): 1733–1754.
Rijn, L. C. van, 1993. Principles of Sediment Transport in Rivers, Estuaries and Coastal Seas.
Aqua Publications, The Netherlands.
Rijn, L. C. van, 2001. General view on sand transport by currents and waves : data analysis
and engineering modelling for uniform and graded sand (TRANSPOR 2000 and CROSMOR 2000 models). Z2899.20 / Z2099.30 / Z2824.30. WL | Delft Hydraulics, Delft, The
Netherlands.
Rijn, L. C. van, 2003. “Sediment transport by currents and waves; general approximation
formulae Coastal Sediments.” In Corpus Christi, USA.
Rijn, L. C. van, J. A. Roelvink and W. T. Horst, 2000. Approximation formulae for sand transport
by currents and waves and implementation in DELFT-MOR. Tech. Rep. Z3054.40, WL |
Delft Hydraulics, Delft, The Netherlands.
Rijn, L. van, D. Walstra, B. Grasmeijer, J. Sutherland, S. Pan and J. Sierra, 2003. “The
predictability of cross-shore bed evolution of sandy beaches at the time scale of storms
and seasons using process-based profile models.” Coastal Engineering 47: 295–327.

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RIZA, 2005. Salt Intrusion Technical Reference. RIZA Institute for Inland Water Management
and Waste Water Treatment. Delivered with SOBEK-RE 2.52.005.
Roelvink, J. A. and M. J. F. Stive, 1989. “Bar-generating cross-shore flow mechanisms on a
beach.” Journal of Geophysical Research 94 (C4): 4785–4800.
SOBEK2, 2012. SOBEK online help. Distributed with SOBEK 2.12.
SOBEK3_TRM, 2013. SOBEK 3 / Hydrodynamics Technical Reference Manual / SOBEK in
Delta Shell. Deltares, Delft. Version: 3.0.1.27817.
Soulsby, R., 1997. Dynamics of marine sands, a manual for practical applications. Thomas
Telford, London.

Soulsby, R. L., A. G. Davies, J. Fredsøe, D. A. Huntley, I. G. Jonnson, D. Myrhaug, R. R.
Simons, A. Temperville and T. J. Zitman, 1993. “Bed shear stresses due to combined
waves and currents.” In Abstracts-in-depth of the Marine Science and Technology G8-M
overall workshop, Grenoble., pages 2.1-1/2.1–4.

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Stelling, G. S. and S. P. A. Duinmeijer, 2003. “A staggered conservative scheme for every Froude number in rapidly varied shallow water flows.” International Journal Numerical
Methods In Fluids 43: 1329–1354.
Stelling, G. S. and A. Verwey, 2006. “Numerical flood simulation.” In Encyclopedia of Hydrological Sciences. John Wiley & Sons.
Stive, M. J. F., 1986. “A model for cross-shore sediment transport.” In Proceedings 20th
International Coastal Engineering Conference, pages 1550–1564. American Society of Civil
Engineers, New York.
Swart, 1974. Offshore sediment transport and equilibrium beach profiles. Ph.D. thesis, Delft
University of Technology, Delft, The Netherlands. Delft Hydraulics Publ. 131.
Thatcher, M. L. and D. R. F. Harleman, 1972. A mathematical model for the prediction of
unsteady salinity intrusion in estuaries. Report no. 144, MIT School of Engineering Massachusetts Institute of Technologie, Department of Civil Engineering.
Wilcock, P. and J. Crowe, 2003. “Surface-based transport model for mixed-size sediment.”
Journal of Hydraulic Engineering 129 (2): 120–128.

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A How to use OpenDA for Delta Shell models
OpenDA is an open-source software tool distributed by the OpenDA Association (see www.
openda.org). It enables the user to calibrate and Ensemble Kalman Filter (EnKF) simulation models, such as Delft3D Flexible Mesh Suite and SOBEK 3. In this document we will
speak of Delta Shell (models).
Both the calibration of Delta Shell models and running them in EnKF-mode is done by using
OpenDA. To run an OpenDA calibration or EnKF-simulation, a so called OpenDA application
(.oda) file is needed, in which the application to be performed is specified. This oda file is the
top of a hierarchy of configuration files that is organized in a directory structure that is usually
setup as indicated below.

)

algorithm contains the configuration file(s) for the calibration or EnKF algorithm
stochObserver contains the configuration file(s) and measurement data for the so
called ‘stochastic observer’, the set of measurements and the specification of their
uncertainty
stochModel contains the configuration file(s) for the so called ‘stochastic model factory’, that specify how model instances can be created. For Delta Shell models, this is
described in

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topDir, containing e.g. for EnKF of a SOBEK 3 model textitSimpleModel:

◦ template contains the base model ( and the associated
model files)

◦ bbWrapperConfig.xml describes the way the model can be addressed. For Delta
Shell models the so-called black-box wrapper is used.

◦ bbModelConfig.xml specifies the <*.md1d> model file and some other optional
settings for repeatedly running the model.

◦ bbStochModelConfig.xml describes which items can be calibrated, and specifies
the relation between the measurement series and the related observation point in
the model

For the all over structure and the content of the various files, the user is referred to the documentation of OpenDA on www.openda.org. Up-to-date examples can be found there.

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B How to use SOBEK 3 models in Delft-FEWS
SOBEK 3 models can be operated in Delft-FEWS. This can be achieved in two steps.

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First, the model must be exported as a so-called Deltares Integrated Model Runner (DIMR)
configuration. The user can do this, by a right-mouse-click in the Project window on the
appropriate and choosing Export. . . . Figure B.1 shows the resulting popup screen.

Figure B.1: Exporting the DIMR configuration

Now, select DIMR configuration, press the OK button and specify the output directory and file
name. SOBEK 3 will export the configuration file (<.xml>), together with all model input files.
Secondly, the model must be configured in Delft-FEWS. This is for trained personnel only.
The user can export detailed information on which model quantities can be exchanged on
which model locations, again by a right-mouse-click in the Project window on the appropriate
and choosing Export. . . . Figure B.2 shows the resulting pop-up screen.

Figure B.2: Exporting the information on input and output for FEWS

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Now, select ModelExchangeItem information, press the OK button and specify an output
directory. SOBEK 3 will export a set of files.
The following files will be very helpfull in configuring the model in FEWS:

fews_ds_integratedmodel_model_data_items.csv
fews_ds_dirintegratedmodel_line_data_items.shp
fews_ds_dirintegratedmodel_node_data_items.shp
Finally, follow the up-to-date instruction which can be found here:

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https://publicwiki.deltares.nl/display/FEWSDOC/How+to+set+up+a+
DeltaShell+Sobek-3+model+in+FEWS

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C How to use OpenMI for SOBEK 3, D-Flow 1D
C.1

Introduction
SOBEK 3 is a modelling system based on the newly developed Delta Shell framework, in
which various modules can be plugged-in. D-RR, D-Flow 1D and D-RTC are the most characteristic modules for SOBEK 3. The D-Flow 1D module in SOBEK 3 models is OpenMI compliant, for OpenMI 2.0 as well as for OpenMI 1.4 (see www.openmi.org). When the OpenMI
is part of an integrated model, the integrated model is OpenMI compliant, but only the DFlow 1D input and output variables are exchanged as OpenMI exchange items.
To couple a SOBEK 3, D-Flow 1D model with other models by means of OpenMI, you need to
provide a so called omi-file (OpenMI file) that specifies:

The omi-file

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C.2

1 The Delta Shell project file (<*.dsproj>) containing your model
2 The name of your D-Flow 1D model or your integrated model in that project
3 Various additional options on how to present and run your model in the OpenMI (see
Section C.3).

OpenMI 2.0 and OpenMI 1.4 both require an omi-file. The two versions differ only in the
header, i.e. the start of the main element. The <*.omi> arguments needed to specify the
SOBEK 3, D-Flow 1D model are for OpenMI 2.0 and OpenMI 1.4.
The differences in the the headers are twofold. First of all, OpenMI 2.0 and OpenMI 1.4. have
different XML Schema Definitions (XSD’s), see:
1 http://www.openmi.org/schemas/v1_4/LinkableComponent.xsd
2 http://www.openmi.org/schemas/v2_0/LinkableComponent.xsd
for the details of these differences.

Second, the header refers, to the ‘wrapper’ for OpenMI 1.4 or for OpenMI 2.0. See also
Section C.4.
Example of an OpenMI 1.4 omi-file

Example of an OpenMI 2.0 omi-file

omi file options (for both OpenMI 1.4 and OpenMI 2.0)
Besides of the two mandatory arguments shown in the omi-files above (the <*.dsproj> file
path and the model name), a few additional arguments can be specified:
Key="ModelId" Value="MyModel" />
Key="DsProjFilePath" Value="./myDeltaShellProject_out.dsproj" />
Key=" SplitSpecificElementSets " Value="grid_point" />
Key=" SeparateProcess " Value="true" />
Key="ModelId" Value="Rhine" />
Key=" ExchangeItemGroups " Value="" />

The are described in the table below.

As shown in the omi-files.

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D Morphology and Sediment Transport

Sediment input file
The sediment input file contains the characteristics of all sediment fractions. In the record
description the name of the quantities are given to simplify their reference in the formulas
given in section D.3.
Remark:
Users of D-Flow 1D are familiar with two versions of the <∗.sed> file: with or without
keywords. D-Flow 1D uses the keyword based version which is described in Table D.1.
Restrictions:
SOBEK 3 does not yet support fixed layer modelling
SOBEK 3 does not yet support multiple sediment fractions (graded sediment)

D.1.1

Input files

Table D.1: Sediment input file with keywords

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D.1

Keyword

Record description

SedimentFileInformation

FileCreatedBy

contains version number of FLOW-GUI

FileCreationDate

creation date and time of the <∗.sed> file

FileVersion

version number

SedimentOverall

NodeRelations

file specifying node relations <∗.nrd>

Sediment

Name

name between # as specified in NamC in mdf-file

SedTyp

type of sediment; must be “sand” or “bedload”: (1 string)

RhoSol

specific density of sediment fraction [kg/m3 ] (1 real)

SedDxx

xx percentile sediment diameter (for sand or bedload)
where xx can take on values from 01 to 99 [m] (1 real)

SedMinDia

minimum sediment diameter (for sand or bedload) [m]
(1 real)

SedDia

median sediment diameter (for sand or bedload) equivalent
to SedD50 [m]
uniform value (1 real)
or file <∗.d50> with spatially varying values at cell centres
(1 string)
continued on next page

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Table D.1 – continued from previous page
Keyword

Record description

SedSg

geometric standard deviation of sediment diameter (for
sand or bedload) [m] (1 real)

SedMaxDia

maximum sediment diameter (for sand or bedload) [m]
(1 real)
dry bed density [kg/m3 ] (1 real)

CDryB
initial sediment mass at bed per unit area [kg/m2 ]
initial sediment layer thickness at bed [m]
uniform value (1 real)
or filename <∗.sdb> with non-uniform values at cell centres (1 string)

SdBUni or
IniSedThick

Name of fraction specific sediment transport formula (for
sand or bedload)

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TraFrm

Table D.2: Options for sediment diameter characteristics

Specified quantities

Assumptions

SedDia (uniform value) or
SedD50 (uniform value)

Piecewise log-uniform distribution
SedD10 = 0.75 SedD50
SedD90 = 1.5 SedD50

SedDia
(filename)
SedD50 (filename)

Lognormal distribution (spatially varying grain size)
SedSg = 1.34

SedDia
(filename)
or
SedD50 (filename), SedSg

Lognormal distribution (spatially varying grain size)

SedDxx (any xx), SedSg

Lognormal distribution

Two SedDxx values

Lognormal distribution
SedSg computed from xx and SedDxx

SedMinDia, SedMaxDia

Loguniform distribution

SedMinDia or SedMaxDia,
One SedDxx value

Loguniform distribution

More than two SedDxx,
SedMinDia, SedMaxDia values

Piecewise loguniform distribution

Other combinations

not allowed

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Example of a version 2 file, with keywords

Morphology input file

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D.1.2

[SedimentFileInformation]
FileCreatedBy
= Delft3D-FLOW-GUI, Version: 3.39.14.03
FileCreationDate = Thu Dec 08 2005, 14:47:46
FileVersion
= 02.00
[SedimentOverall]
IopSus
= 0
Suspended sediment size is Y/N
calculated dependent on d50
Cref
= 1.60e+03
[kg/m3] CSoil Reference density for hindered
settling
[Sediment]
Name
= #Sediment1#
Name of sediment
SedTyp
= bedload
Must be "sand" or "bedload"
RhoSol
= 2.6500000e+003 [kg/m3] Specific density
SedDia
= 2.0000000e-004 [m]
Median sediment diameter (D50)
CDryB
= 1.6000000e+003 [kg/m3] Dry bed density
IniSedThick
= 0.50e+000
[m]
Initial sediment layer thickness at bed
(uniform value or file name)
FacDSS
= 1.0e+0
[-]
FacDss*SedDia = Initial suspended
sediment diameter.

The morphological input file contains additional information necessary for a morphodynamic
run. Users of D-Flow 1D are familiar with two versions of the file, like the <∗.sed> file: with
or without keywords. D-Flow 1D uses the version with keywords.
Table D.3: Morphological input file with keywords

Keyword

Record description

MorphologyFileInformation

FileCreatedBy

contains version number of FLOW-GUI

FileCreationDate

creation date and time of the <∗.mor> file

FileVersion

version number

Morphology

MorFac

morphological scale factor
constant (1 real) or
file with time-dependent values (string)
in case of a file: no text may be used after the
filename

MorStt

time interval in minutes after the start of the simulation after which morphological changes will be calculated (1 real)

BedUpd

update bed level during flow run (1 logical: false or
true)
continued on next page

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Table D.3 – continued from previous page
Keyword

Record description

BcFil

file containing morphological boundary conditions (1
string)

Boundary
name of boundary node ID (1 string)

IBedCond

bedload or bed level boundary condition (1 integer in
the range 0 to 5)
0
no bed level constraint
1
bed level fixed
2
depth specified as function of time
3
depth change specified as function of
time
4
bedload transport rate prescribed (volume rate of bed material)
5
bedload transport rate prescribed (volume rate of stone)

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Name

the Boundary block can be repeated for other boundaries

For these boundary conditions you need to specify the imposed time-series in the file referred
to using the BcFil keyword. File format described in section D.1.4.
Example of a version 2 file, with keywords:

[MorphologyFileInformation]
FileCreatedBy
= Delft3D-FLOW-GUI, Version: 3.39.14.03
FileCreationDate = Thu Dec 08 2005, 14:47:50
FileVersion
= 02.00
[Morphology]
MorFac
= 1.0000000e+000 [-] Morphological scale factor
MorStt
= 7.20e+02
[min] Spin-up interval from TStart till start of morph changes
BedUpd
= true
Update bathymetry during flow run
BcFil
= #dmor.bcm#
Name of morphological boundary condition file
[Boundary]
Name
= #Node001#
Boundary node ID
IBedCond = 4
0: free none - 1: fixed none - 2: time series depth m
3: depth change prescribed depth change m/s
4: transport incl pores prescribed transport incl pores m3/s
5: transport excl pores prescribed transport excl pores m3/s
[Boundary]
Name
= #Node002#
Boundary node ID
IBedCond = 0

Remark:
The file for specifying bedload, bed level and/or bed composition boundary conditions
is described in section D.1.4.
Restriction:

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Table D.4: Additional transport relations

Bedload

Affected
by Waves

IFORM

D.4.1, Van Rijn (1993)
D.4.2, Engelund-Hansen (1967)
D.4.3, Meyer-Peter-Muller (1948)
D.4.4, General formula
D.4.5, Bijker (1971)
D.4.6, Van Rijn (1984)
D.4.7, Soulsby/Van Rijn
D.4.8, Soulsby
D.4.9, Ashida–Michiue (1974)
D.4.10, Wilcock–Crowe (2003)
D.4.11, Gaeuman et al. (2009) laboratory calibration
D.4.12, Gaeuman et al. (2009) Trinity
River calibration
User-defined

Bedload + suspended
Total transport
Total transport
Total transport
Bedload + suspended
Bedload + suspended
Bedload + suspended
Bedload + suspended
Total transport
Bedload
Bedload

Yes
No
No
No
Yes
No
Yes
Yes
Yes
No
No

-1
1
2
4
5
7
11
12
14
16
17

Bedload

Yes

—

Formula

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Bedload + suspended

The values of the parameters are not checked against their domains.
D.1.3

Sediment transport input file

By default, the formulations of Van Rijn et al. (2000) are applied for the suspended and bedload transport of non-cohesive sediment. In addition this feature offers a number of extra
sediment transport relations for non-cohesive sediment; Table D.4 gives an overview of those
additional formulae.
If you want to use one of these formulae, you must create a sediment transport input file
<∗.tra>. The filename of the sediment input file must be specified in the sediment input
file (formula used for only the selected non-cohesive sediment fraction) using the keyword
TraFrm. In the former case, use the Data Group Addition parameters in the FLOW-GUI with
keyword and value: TraFrm=#name.tra#. For these pre-defined alternative transport
relations the sediment transport input file should comply with the following specifications:

The file may start with an arbitrary number of lines not containing the text IFORM.
Then a line starting with sediment transport formula number IFORM and containing text
IFORM.

Then an arbitrary number of lines starting with an asterisk (∗) may follow.
Then a line starting with the number sign (#) followed by a transport formula number
optionally followed by text identifying the transport formula for the user. The next lines
should contain the parameter values of the transport formula coefficients: one parameter
value per line optionally followed by text identifying the parameter. There may be an
arbitrary number of blocks starting with # in the file, but exactly one should correspond to
the transport formula number IFORM specified above.
An example file for transport formula 5 referred to as “Bijker (1971)” is provided below. The
following table lists the parameters to be specified in the sediment transport input file for each
separate transport formula.

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Table D.5: Transport formula parameters

Parameter

D.4.1, Van Rijn (1993)

none

D.4.2, Engelund-Hansen (1967)

calibration coefficient α
bed roughness height rk (dummy)

D.4.3, Meyer-Peter-Muller (1948)

calibration coefficient α
dummy argument

D.4.4, General formula

calibration coefficient α
power b
power c
ripple factor or efficiency factor µ
critical mobility factor θc

D.4.5, Bijker (1971)

calibration coefficient b for shallow water

Unit

Formula

calibration coefficient b for deep water

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shallow water (hw /h) criterion Cs
deep water (hw /h) criterion Cd
dummy argument
bed roughness height rc
settling velocity w
porosity ε
wave period Tuser (used if computed
wave period < 10−6 )

NA
m
m/s
s

D.4.6, Van Rijn (1984)

calibration coefficient α1
dummy argument
reference level ξc
settling velocty ws

NA
m
m/s

D.4.7, Soulsby/Van Rijn

calibration coefficient Acal
D90 /D50 ratio
z0 roughness height

D.4.8, Soulsby

calibration coefficient Acal
model index modind
D50 /z0 ratio χ

D.4.9, Ashida–Michiue (1974)

calibration coefficient α
critical mobility factor θc
power m
power p
power q

D.4.10, Wilcock–Crowe (2003)

none

D.4.11, Gaeuman et al. (2009) laboratory calibration

calibration coefficient θc0

calibration coefficient α0

calibration coefficient θc0

calibration coefficient α0

D.4.12, Gaeuman et al. (2009) Trinity
River calibration

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Formula

Parameter

Unit

User-defined

none

Example for Engelund-Hansen (1967) formula:
IFORM
ENGELUND-HANSEN

DR
AF

1
#1
1.00
0.0

Remarks:
Van Rijn (1993) does not require any additional parameters. Only the transport formula
number (-1) followed by the string IFORM is required.
The user-defined transport formula requires a keyword based transport input file as
described below.
The keyword IFORM must be present in the same line as the formula number.
The file should not contain tabs.

Example for Meyer-Peter Mueller (1948) formula:
2
#2
1.00
0.0

IFORM
MEYER-PETER-MULLER

Example for Van Rijn 1993 formula:

This is an example of a sediment transport input file to be used with the Van Rijn (1993)
formulations in which case there is no need for additional parameters. The file could simply
read:
-1

D.1.4

IFORM

Sediment transport and morphology boundary condition file

The bcm file contains time-series for sediment transport and morphology boundary conditions.
For each open boundary segment that according to the boundary characteristics given in the
<∗.mor> file requires boundary data, the data is given in two related blocks:

A header block containing a number of compulsory and optional keywords accompanied
by their values.

A data block containing the time dependent data.
Description header block:

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Required

Value

table-name

arbitrary string

location

yes

’boundary node ID’

time-function

{’non-equidistant’} or ’equidistant’

time-step

yes

time step only in case of time-function ’equidistant’

reference-time

yes

yyyymmdd, yyymmdd hhmmss or ’from model’

time-unit

’years’, ’decades’, ’days’, ’hours’, {’minutes’}, ’seconds’, ’ddhhmmss’ or ’date’

interpolation

{’linear’} or ’block’

extrapolation

’periodic’, ’constant’ or {’none’}

parameter

yes

’parameter name and location’ units ’[ccc]’

DR
AF

Text

records-in-table no

number of times/lines in the data block

Remarks:
Default parameter values are indicated in braces.
Reference-time not required if time-unit equals ’date’.
Unit strings are currently not interpreted by SOBEK 3.

The ‘parameter name and location’ strings depend on the boundary type chosen, i.e. quantity
type to be specified. The following table lists the base parameter names. The full ‘parameter
name and location’ string is a concatenation of the indicated base parameter name, optionally
followed by a single space character and the user-defined sediment name. Bedload transport should be specified for only the non-mud fractions (i.e. sand and bedload fractions only)
whereas bed composition should be specified for all fractions. The parameters for multiple
sediment fractions must occur in the same order as in which the sediment fractions have
been defined.
Boundary type

Base
name

parameter

Unit

Multiplicity

m
m/s
m3 /(sm)
m3 /(sm)

1
1
#nonmud
#nonmud

sediment transport and bed level
0:
1:
2:
3:
4:
5:

free
fixed
time series
depth change prescribed
transport incl pores prescribed
transport excl pores prescribed

none
none
depth
depth change
transport incl pores
transport excl pores

Description data block:

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Record

Record description

each record

Time in time-units after the reference-time and followed by as many values as parameters have been defined in the description block (all reals).
In case of time-function ‘equidistant’, the first (time) column should be
dropped. In case of time-unit ‘date’ the date and time should be specified as one string using the format: yyyymmddhhmmss.

Remarks:
Maximum record length is 512.
The morphological boundary conditions will only be used at inflow boundaries.
The parameter name of the column should read ‘time’.

Example:

D.1.5

DR
AF

table-name
’Boundary Section : 1’
contents
’Uniform’
location
’Node001’
time-function
’non-equidistant’
reference-time
20141217
time-unit
’minutes’
interpolation
’linear’
parameter
’time’ unit ’[min]’
parameter
’transport incl pores Sediment1’ unit ’[m3/s/m]’
records-in-table
2
0.0000
0.000625
6.7108864e+07
0.000625

Nodal Relations Definition file

The nodal relation definition file contains information about the distribution of sediment on
nodal points. A nodal point relation is defined for every node to which three or more branches
are connected, such as bifurcations. By default a proportional function will be used, identical
to Method=function with k=1 and m=0.
Table D.6: Nodal relation file with keywords

Keyword

Record description

General

TableFile

name of the tablefile (e.g. ’table.tbl’)

NodalPointRelation

Node

name of the node

Method

table or function

Table

If method is table, define the name of the table in the
TableFile to use

If method is function, the value of the ’k’ parameter
continued on next page

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Table D.6 – continued from previous page

If method is function, the value of the ’m’ parameter

BranchIn

The name of the incoming branch

BranchOut1

Only necessary of method is table. Name of outcoming
branch nr 1

BranchOut2

Only necessary of method is table. Name of outcoming
branch nr 2

Table file

Record description

The table file is used to define tables for the nodal relation method ’table’. The file format
is akin to D-Flow 1D <∗.pol> or <∗.ldb> files. A table is defined by a name. Each table
consists of two columns and any number of rows. Comments can be inserted by prefixing a
line with an asterix (∗)

DR
AF

D.1.6

Keyword

The first column of a table file is always defined as the ratio of flow distribution between
BranchOut1 and BranchOut2. The second column is always defined as the ratio of the
sediment distribution. The user should specify in the Nodal Relation File (see D.1.5) which
branch is ’BranchOut1’ and which branch is ’BranchOut2’.
Remark:
The table method can not be used for trifurcations or other situations with more than 2
outflowing branches.
Example table file

* Bifurcation relationship
* column 1 = QBranch1/QBranch2
* column 2 = SBranch1/SBranch2
TABL3
4 2
1.0
1.0
2.0
2.0
3.0
2.0
4.0
2.0
* column 1 = QBranch4/QBranch5
* column 2 = SBranch4/SBranch5
TABL6
4 2
1.0
1.0
2.0
2.0
3.0
2.0
4.0
2.0

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D.2

Output files
Morphology and Sediment Transport output is written to files, which are
located in the dsproj_data/water_flow_1d_output/work directory.
Delta Shell offers no tool to read <∗.his> files. Users familiar with SOBEK 2 can use ODS
View. The free Open Earth repository has a Matlab scripts available to read <∗.his> files.

D.3

Bedload sediment transport of non-cohesive sediment

D.3.1

Basic formulation

Bedload (or, for the simpler transport formulae, total load) transport is calculated for all “sand”
and “bedload” sediment fractions by broadly according to the following approach: first, the
magnitude and direction of the bedload transport at the cell centres is computed using the
transport formula selected (See section D.4), subsequently the transport rates at the cell
interfaces are determined.

DR
AF

For simulations including waves the magnitude and direction of the bedload transport on a
horizontal bed are calculated using the transport formula selected assuming sufficient sediment and ignoring bed composition except for e.g. hiding and exposure effects on the critical
shear stresses.
The default sediment transport formula is Van Rijn (1993, cf. section D.4.1).
Some of the sediment transport formulae prescribe the bedload transport direction whereas
others predict just the magnitude of the sediment transport. In the latter case the initial transport direction will be assumed to be equal to the direction of the characteristic (near-bed) flow
direction.
D.3.2

Calculation of bedload transport at open boundaries

At open boundaries the user may either prescribe the bed level development or the bedload
transport rates. In the latter case the bedload transport rates are known from the model
input, whereas in the former case the effective bedload transport rates at the boundary could
be derived from the mass balance at the open boundary point. The bed level boundary
condition is imposed at the same location where a water level boundary condition is imposed,
that is at the grid cell just outside the model domain. A consequence of this approach is
that the bed level at the first grid cell inside the model domain will not exactly behave as
you imposed, but in general it will follow the imposed behaviour closely. In case of multiple
sediment fractions, a boundary condition for the bed composition is also needed at inflow
boundaries. See section D.1.2 and section D.1.4 for imposing various morphological boundary
conditions.

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D.4

Transport formulations for non-cohesive sediment
This special feature offers a number of standard sediment transport formulations for noncohesive sediment. Table D.7 gives a summary of the additional formulae.
Table D.7: Additional transport relations

Waves

Bedload + suspended
Total transport
Total transport
Total transport
Bedload + suspended
Bedload + suspended
Bedload + suspended
Bedload + suspended
Total transport
Bedload
Bedload
Bedload

Yes
No
No
No
Yes
No
Yes
Yes
No
No
No
No

Bedload

DR
AF

D.4.1

Formula

Van Rijn (1993)

Van Rijn (1993) distinguishes between sediment transport below the reference height a which
is treated as bedload transport and that above the reference height which is treated as
suspended-load. Sediment is entrained in the water column by imposing a reference concentration at the reference height.
Reference concentration
The reference concentration is calculated in accordance with Van Rijn et al. (2000) as:

c(`)
a
where:
(`)

1.5
(`)
(`)
D50 Ta
= 0.015ρ(`)
0.3

s
(`)
a D∗

(D.1)

mass concentration at reference height a

In order to evaluate this expression the following quantities must be calculated:
(`)

D∗

non-dimensional particle diameter:

D∗(`)
(`)

(`)
D50

(s(`) − 1)g
ν2

1/3
(D.2)

non-dimensional bed-shear stress:
(`)

Ta(`) =

138 of 160

(`)

(µc τb,cw + µw τb,w ) − τcr
(`)

(D.3)

τcr

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Morphology and Sediment Transport

(`)

µc

efficiency factor current:

µ(`)
c =
f 0 (`)
c

f 0 (`)
c
fc

(D.4)

gain related friction factor:

"
(`)
f 0c

(`)

= 0.24

12h

log

!#−2
(D.5)

(`)

3D90

total current-related friction factor:

= 0.24

log

12h
ks

−2

τb,cw = ρw u2∗

(`)

µw

(D.7)

efficiency factor waves:

µ(`)
w

τb,w

1
= max 0.063,
8

2 !
Hs
1.5 −
h

(D.8)

bed shear stress due to waves:

2
1
bδ
τb,w = ρw fw U
4

(D.6)

bed shear stress due to current in the presence of waves. Note that the bed
shear velocity u∗ is calculated in such a way that Van Rijn’s wave-current interaction factor αcw is not required.

DR
AF

τb,cw

fc(`)

(D.9)

total wave-related friction factor (≡ Equations (D.49) and (D.90)):



Âδ
ks,w

fw = exp −6 + 5.2

!−0.19 


(D.10)

To avoid the need for excessive user input, the wave related roughness ks,w is related to the
estimated ripple height, using the relationship:

ks,w = RWAVE · ∆r , with∆r = 0.025 and 0.01 m ≤ ks,w ≤ 0.1 m

(D.11)

where:

RWAVE the user-defined wave roughness adjustment factor. Recommended to be in
the range 1–3, default = 2.
(`)
τcr

critical bed shear stress:
(`)

(`)
(`)
τcr
= (ρ(`)
s − ρw )gD50 θcr
(`)

θcr

Deltares

(D.12)

(`)

threshold parameter θcr is calculated according to the classical Shields curve
as modelled by Van Rijn (1993) as a function of the non-dimensional grain size
D∗ . This avoids the need for iteration.

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(`)

Note: for clarity, in this expression the symbol D∗ has been used where D∗
would be more correct:

(`)
θcr

a
Âδ
(`)
D50
(`)
D90
h
ka
ks
ks,w
uz

zu
∆r
δm
δw

1 < D∗ ≤ 4
4 < D∗ ≤ 10
10 < D∗ ≤ 20
20 < D∗ ≤ 150
150 < D∗

(D.13)

Van Rijn’s reference height
peak orbital excursion at the bed: Âδ =

Tp Ûδ
.
2π

median sediment diameter
(`)

(`)

90 % sediment passing size: D90 = 1.5D50
water depth
apparent bed roughness felt by the flow when waves are present.
user-defined current-related effective roughness height (space varying)
wave-related roughness, calculated from ripple height, see Equation (D.11)
velocity magnitude taken from a near-bed computational layer. In a current-only
situation the velocity in the bottom computational layer is used. Otherwise, if
waves are active, the velocity is taken from the layer closest to the height of the
top of the wave mixing layer δ . √
peak orbital velocity at the bed: 2 × RMS orbital velocity at bed, taken from the
wave module.
height above bed of the near-bed velocity (uz ) used in the calculation of bottom
shear stress due to current
estimated ripple height, see Equation (D.11)
thickness of wave boundary mixing layer following Van Rijn (1993): 3δw (and
δm ≥ k a )
wave boundary layer thickness:

DR
AF

bδ
U


0.24D∗−1 ,



 0.14D∗−0.64 ,
=
0.04D∗−0.1 ,


 0.013D∗0.29 ,

0.055,

δw = 0.072Âδ

Âδ
ks,w

−0.25

We emphasise the following points regarding this implementation:

The bottom shear stress due to currents is based on a near-bed velocity taken from the
hydrodynamic calculations, rather than the depth-averaged velocity used by Van Rijn.
All sediment calculations are based on hydrodynamic calculations from the previous half
time-step. We find that this is necessary to prevent unstable oscillations developing.
The apparent roughness felt by the flow (ka ) is dependent on the hydrodynamic wave-current
interaction model applied. At this time, Van Rijn’s wave-current interaction model is not available in Delft3D-FLOW. This means that it is not possible for a user to exactly reproduce results
obtained using Van Rijn’s full formulations for waves and currents.

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Adjustment of the representative diameter of suspended sediment
(`)

The representative diameter of the suspended sediment Ds generally given by the userdefined sediment diameter SEDDIA (D50 of bed material) multiplied by the user-defined factor
FACDSS (see also remarks) can be overruled in case the Van Rijn (1993) transport formula is
selected. This achieved by setting IOPSUS=1 the representative diameter of the suspended
sediment will then be set to:

(`)

where Ta

(D.14)

is given by equation (D.3).

Ds(`)


(`)
(`)

 0.64D
50

for TA ≤ 1
(`)
(`)
(`)
D50 1 + 0.015 TA − 25
for 1 < TA ≤ 25
=

 (`)
(`)
D50
for 25 < TA

Bedload transport rate

DR
AF

For simulations including waves the magnitude and direction of the bedload transport on a
horizontal bed are calculated using an approximation method developed by Van Rijn et al.
(2003). The method computes the magnitude of the bedload transport as:
(`)

|Sb | = 0.006ρs ws D50 M 0.5 Me0.7

(D.15)

where:

Sb
M
Me

bedload transport [kg m-1 s-1 ]
sediment mobility number due to waves and currents [-]
excess sediment mobility number [-]
2
veff
M=
(s − 1) gD50
(veff − vcr )2
Me =
(s − 1) gD50
q
2
veff = vR2 + Uon

(D.16)
(D.17)
(D.18)

in which:

vcr
vR

Uon

critical depth averaged velocity for initiation of motion (based on a parameterisation of the Shields curve) [m/s]
magnitude of an equivalent depth-averaged velocity computed from the velocity
in the bottom computational layer, assuming a logarithmic velocity profile [m/s]
near-bed peak orbital velocity [m/s] in onshore direction (in the direction on
wave propagation) based on the significant wave height

Uon (and Uof f used below) are the high frequency near-bed orbital velocities due to short
waves and are computed using a modification of the method of Isobe and Horikawa (1982).
This method is a parameterisation of fifth-order Stokes wave theory and third-order cnoidal
wave theory which can be used over a wide range of wave conditions and takes into account the non-linear effects that occur as waves propagate in shallow water (Grasmeijer and
Van Rijn, 1998).
The direction of the bedload transport vector is determined by assuming that it is composed
of two parts: part due to current (Sb,c ) which acts in the direction of the near-bed current, and

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part due to waves (Sb,w ) which acts in the direction of wave propagation. These components
are determined as follows:

Sb
Sb,c = p
1 + r2 + 2 |r| cos ϕ

(D.19)

|Sb,w | = r |Sb,c |

(D.20)

where:

(|Uon | − vcr )3
(|vR | − vcr )3

(D.21)

Sb,w = 0 if r < 0.01, Sb,c = 0 if r > 100, and ϕ = angle between current and wave

direction for which Van Rijn (2003) suggests a constant value of 90◦ .

DR
AF

Also included in the “bedload” transport vector is an estimation of the suspended sediment
transport due to wave asymmetry effects. This is intended to model the effect of asymmetric
wave orbital velocities on the transport of suspended material within about 0.5 m of the bed
(the bulk of the suspended transport affected by high frequency wave oscillations).
This wave-related suspended sediment transport is again modelled using an approximation
method proposed by Van Rijn (2001):

Ss,w = fSUSW γUA LT
where:

Ss,w
fSUSW
γ
UA
LT

(D.22)

wave-related suspended transport [kg/(ms)]
user-defined tuning parameter
phase lag coefficient (= 0.2)
velocity asymmetry value [m/s] =

4 −U 4
Uon
of f
3 +U 3
Uon
of f

suspended sediment load [kg/m ] = 0.007ρs D50 Me

The three separate transport modes are imposed separately. The direction of the bedload
due to currents Sb,c is assumed to be equal to the direction of the current, whereas the two
wave related transport components Sb,w and Ss,w take on the wave propagation direction.
This results in the following transport components:

ub,u
|Sb,c |
|ub |
ub,v
=
|Sb,c |
|ub |

Sbc,u =

(D.23)

Sbc,v

(D.24)

Sbw,u = Sb,w cos φ
Sbw,v = Sb,w sin φ

(D.25)

Ssw,u = Ss,w cos φ
Ssw,v = Ss,w sin φ

(D.27)

(D.26)

(D.28)

where φ is the local angle between the direction of wave propagation and the computational
grid. The different transport components can be calibrated independently by using the Bed,
BedW and SusW keywords in the morphology input file.

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D.4.2

Engelund-Hansen (1967)
The Engelund-Hansen sediment transport relation has frequently been used in rivers and
estuaries. It reads:

0.05αq 5
S = Sb + Ss,eq = √ 3 2
gC ∆ D50

(D.29)

where:

q
∆
C
α

magnitude of flow velocity
the relative density (ρs − ρw )/ρw
Chézy friction coefficient
calibration coefficient (O(1))

The transport rate is imposed as bedload transport due to currents Sbc . The following formula
specific parameters have to be specified in the input files of the Transport module (see Section
D.1.3): calibration coefficient α and roughness height rk .

D.4.3

DR
AF

Remarks:
The D50 grain size diameter is based on the sediment fraction considered.
A second formula specific input parameter (rk ) is required for the Engelund-Hansen
formula. This parameter, which represents the roughness height for currents alone in
[m], is only used to determine the C value when the Chézy friction in the flow has not
been defined. Generally, this parameter can thus be treated as a dummy parameter.
Meyer-Peter-Muller (1948)

The Meyer-Peter-Muller sediment transport relation is slightly more advanced than the EngelundHansen formula, as it includes a critical shear stress for transport. It reads:

S = 8αD50

p
∆gD50 (µθ − ξθcr )3/2

(D.30)

where:

α
∆
µ
θcr
ξ

calibration coefficient (O(1))
the relative density (ρs − ρw )/ρw
ripple factor or efficiency factor
critical mobility parameter (= 0.047)
hiding and exposure factor for the sediment fraction considered

and the Shields mobility parameter θ given by

θ=

q 2
C

1
∆D50

(D.31)

in which q is the magnitude of the flow velocity [m/s]. The ripple factor µ reads:

µ = min

C
Cg,90

1.5

!
, 1.0

(D.32)

where Cg,90 is the Chézy coefficient related to grains, given by:
10

Cg,90 = 18 log

Deltares

12(d + ζ)
D90

(D.33)

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with D90 specified in [m]. The transport rate is imposed as bedload transport due to currents
Sbc . The following formula specific parameters have to be specified in the input files of the
Transport module (see Section D.1.3): calibration coefficient α and a dummy value.
Remark:
The D50 is based on the sediment fraction considered, the D90 grain size diameters is
based on the composition of the local sediment mixture.
D.4.4

General formula

S = αD50

∆gD50 θb (µθ − ξθcr )c

The general sediment transport relation has the structure of the Meyer-Peter-Muller formula,
but all coefficients and powers can be adjusted to fit your requirements. This formula is aimed
at experienced users that want to investigate certain parameters settings. In general this
formula should not be used. It reads:
(D.34)

where ξ is the hiding and exposure factor for the sediment fraction considered and

q 2

1
∆D50

DR
AF

θ=

(D.35)

in which q is the magnitude of the flow velocity.

The transport rate is imposed as bedload transport due to currents Sbc . The following parameters have to be specified in the input files of the Transport module (see Section D.1.3):
calibration coefficient α, powers b and c, ripple factor or efficiency factor µ, critical mobility
parameter θcr .
D.4.5

Bijker (1971)

The Bijker formula sediment transport relation is a popular formula which is often used in
coastal areas. It is robust and generally produces sediment transport of the right order of
magnitude under the combined action of currents and waves. Bedload and suspended load
are treated separately. The near-bed sediment transport (Sb ) and the suspended sediment
transport (Ss ) are given by the formulations in the first sub-section. It is possible to include
sediment transport in the wave direction due to wave asymmetry and bed slope following
the Bailard approach, see Bailard (1981), Stive (1986). Separate expressions for the wave
asymmetry and bed slope components are included:

~b = S
~b0 + S
~b,asymm + S
~s,asymm + S
~b,slope + S
~s,slope
S
~s = S
~s0
S

(D.36)
(D.37)

where Sb0 and Ss0 are the sediment transport in flow direction as computed according to the
formulations of Bijker in the first sub-section, and the asymmetry and bed slope components
for bedload and suspended transport are defined in the second sub-section. Both bedload and
suspended load terms are incorporated in the bedload transport for further processing. The
transport vectors are imposed as bedload transport vector due to currents Sbc and suspended
load transport magnitude Ss , from which the equilibrium concentration is derived, respectively.

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Basic formulation
The basic formulation of the sediment transport formula according to Bijker is given by:

q√
g (1 − φ) exp (Ar )
C

33.0h
Ss = 1.83Sb I1 ln
+ I2
rc

Sb = bD50

(D.38)
(D.39)

where

C
h
q
φ

Chézy coefficient (as specified in input of Delft3D-FLOW module)
water depth
flow velocity magnitude
porosity

and

Ar = max (−50, min (100, Ara ))

DR
AF

D.4.5.1

(hw /h) − Cd
b = BD + max 0, min 1,
(BS − BD)
Cs − Cd

I1 = 0.216

I2 = 0.216

rc z∗ −1
h
z∗
1 − rhc

1−y
y

(D.40)

(D.41)

z∗

(D.42)

rc /h

ln y

1−y
y

z∗

(D.43)

rc /h

where

BS
BD
Cs
Cd
rc
and

Coefficient b for shallow water (default value 5)
Coefficient b for deep water (default value 2)
Shallow water criterion (Hs /h) (default value 0.05)
Deep water criterion (default value 0.4)
Roughness height for currents [m]

Ara =

µ=

z∗ =

Deltares

−0.27∆D50 C 2

2
Ub
2
µq 1 + 0.5 ψ q

C
10
18 log(12h/D90 )

1.5
(D.45)

w
√
κq g
C

r
1 + 0.5

ψ Uqb

(D.44)

(D.46)

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Ub =

ω=

ωhw
2 sinh (kw h)

(D.47)

2π
T

(D.48)

5.123
fw = exp −5.977 + 0.194
a0

(D.49)

(≡ Equations ??, (D.10) and (D.90)):

Ub
a0 = max 2,
ωrc
(

where

C
hw
kw
T
Ub
w
∆
κ

fw
2g

if wave effects are included (T > 0)

DR
AF

ψ=

C
0

(D.50)

(D.51)

otherwise

Chézy coefficient (as specified in input of Delft3D-FLOW module)
wave height (Hrms )
wave number
wave period computed by the waves model or specified by you as T user.
wave velocity
sediment fall velocity [m/s]
relative density (ρs − ρw )/ρw
Von Kármán constant (0.41)

The following formula specific parameters have to be specified in the input files of the Transport module (see Section D.1.3): BS , BD , Cs , Cd , dummy argument, rc , w , ε and T user.
D.4.5.2

Transport in wave propagation direction (Bailard-approach)

If the Bijker formula is selected it is possible to include sediment transport in the wave direction
due to wave asymmetry following the Bailard approach, see Bailard (1981) and Stive (1986).
For a detailed description of the implementation you are referred to Nipius (1998).
Separate expressions for the wave asymmetry and bed slope components are included for
both bedload and suspended load. Both extra bedload and suspended load transport vectors
are added to the bedload transport as computed in the previous sub-section:

~b = S
~b0 + S
~b,asymm + S
~s,asymm + S
~b,slope + S
~s,slope
S

(D.52)

where the asymmetry components for respectively the bedload and suspended transport in
wave direction are written as:

Sb;asymm (t) =

ρcf εb
|u(t)|2 u(t)
(ρs − ρ) g (1 − φ) tan ϕ

(D.53)

Ss;asymm (t) =

ρcf εs
|u(t)|3 u(t)
(ρs − ρ) g (1 − φ) w

(D.54)

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from which the components in ξ and η direction are obtained by multiplying with the cosine
and sine of the wave angle θ w and the bed slope components as:

Sb;slope,ξ (t) =

ρcf εb
1
∂zb
|u(t)|3
(ρs − ρ) g (1 − φ) tan ϕ tan ϕ
∂ξ

(D.55)

Ss;slope,ξ (t) =

ρcf εs
εs
∂zb
|u(t)|5
(ρs − ρ) g (1 − φ) w w
∂ξ

(D.56)

and similar for the η direction, where:

u(t)
ρ
ρs
cf
φ
ϕ
w
εb
εs

DR
AF

near bed velocity signal [m/s]
density of water [kg/m3 ]
density of the sediment [kg/m3 ]
coefficient of the bottom shear stress [-] (constant value of 0.005)
porosity [-] (constant value of 0.4)
natural angle of repose [-] (constant value of tan ϕ = 0.63)
sediment fall velocity [m/s]
efficiency factor of bedload transport [-] (constant value of 0.10)
efficiency factor of suspended transport [-] (constant value of 0.02, but in implemented expression for suspended bed slope transport the second εs is replaced
by a user-defined calibration factor; see Equation (D.59)).

These transports are determined by generating velocity signals of the orbital velocities near
the bed by using the Rienecker and Fenton (1981) method, see also Roelvink and Stive
(1989).
The (short wave) averaged sediment transport due to wave asymmetry, Equations (D.53) and
(D.54), is determined by using the following averaging expressions of the near bed velocity
signal (calibration coefficients included):

u |u|2 = F acA ũ |ũ|2 + 3F acU ū |ũ|2

(D.57)

u |u|3 = F acA ũ |ũ|3 + 4F acU ū |ũ|3

(D.58)

in which:

ũ
ū
F acA
F acU

orbital velocity signal
averaged flow velocity (due to tide, undertow, wind, etc.)
user-defined calibration coefficient for the wave asymmetry
user-defined calibration coefficient for the averaged flow

The suspended transport relation due to the bed slope according to Equation (D.56) is implemented as:

Ss;slope,ξ (t) =

εsl
∂zb
ρcf εs
|u(t)|5
(ρs − ρ) g (1 − φ) w w
∂ξ

(D.59)

where:

εsl

user-defined calibration coefficient EpsSL

To activate this transport option, you have to create a separate file named which
contains on three separate lines the calibration coefficients: FacA, FacU and EpsSL. The

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other parameters are read from the transport input file or are specified as general sediment
characteristics.
Note: the user-defined FacU value is currently treated as a dummy value, FacU = 0.0 will
always be used.
A validation study (Nipius, 1998) showed that the following coefficient settings yielded the best
results for the Dutch coast:

FacA = 0.4
FacU = 0.0
EpsSL = 0.11

If a relatively straight coast is considered the effect of the parameters is:

The wave asymmetry causes onshore directed sediment transport (i.e. in the wave propa-

D.4.6

DR
AF

gation direction). An increased FacA results in an increased onshore transport and hence
steepening of the cross-shore bottom profile.
The bed slope transport is in general offshore directed. By increasing EpsSL an increased flattening of the bottom profile occurs (i.e. increased offshore transports).
The ratio between these parameters determines the balance between onshore and offshore transport and hence the shape and slope of the cross-shore bottom profile. The
associated response time of the cross-shore morphology can be influenced by modifying
the values of the two parameters, but maintaining a constant ratio. Increased values result
in increased gross transports and consequently a reduced morphological response time
(and vice versa).
Van Rijn (1984)

The Van Rijn (1984a,b,c) sediment transport relation is a transport formula commonly used for
fine sediments in situations without waves. Separate expressions for bedload and suspended
load are given. The bedload transport rate is given by:


q
 0.053 ∆gD3 D−0.3 T 2.1 for T < 3.0
50 ∗
q
Sb =
 0.1 ∆gD3 D−0.3 T 1.5
for T ≥ 3.0
50 ∗

(D.60)

where T is a dimensionless bed shear parameter, written as:

T =

µc τbc − τbcr
τbcr

(D.61)

It is normalised with the critical bed shear stress according to Shields (τbcr ), the term µc τbc is
the effective shear stress. The formulas of the shear stresses are

1
τbc = ρw fcb q 2
8
0.24
fcb =
10
( log (12h/ξc ))2
10
2
18 log (12h/ξc )
µc =
Cg,90

(D.62)
(D.63)

(D.64)

where Cg,90 is the grain related Chézy coefficient
10

Cg,90 = 18 log

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12h
3D90

(D.65)

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The critical shear stress is written according to Shields:

τbcr = ρw ∆gD50 θcr

(D.66)

in which θcr is the Shields parameter which is a function of the dimensionless particle parameter D∗ :

D∗ = D50

∆g
ν2

13
(D.67)

The suspended transport formulation reads:

Ss = fcs qhCa

(D.68)

DR
AF

In which Ca is the reference concentration, q depth averaged velocity, h the water depth and
fcs is a shape factor of which only an approximate solution exists:

f0 (zc ) if zc 6= 1.2
fcs =
(D.69)
f1 (zc ) if zc = 1.2

(ξc /h)zc − (ξc /h)1.2
f0 (zc ) =
(1 − ξc /h)zc (1.2 − zc )

f1 (zc ) =

ξc /h
1 − ξc /h

(D.70)

1.2

ln (ξc /h)

(D.71)

where ξc is the reference level or roughness height (can be interpreted as the bedload layer
thickness) and zc the suspension number:

ws
+φ
zc = min 20,
βκu∗
r
fcb
u∗ = q
8
2 !
ws
β = min 1.5, 1 + 2
u∗
0.8
0.4
ws
Ca
φ = 2.5
u∗
0.65

(D.72)

(D.73)
(D.74)

(D.75)

The reference concentration is written as:

Ca = 0.015α1

D50 T 1.5
ξc D∗0.3

(D.76)

The bedload transport rate is imposed as bedload transport due to currents Sbc ,while the
computed suspended load transport rate is converted into a reference concentration equal to
fcs Ca . The following formula specific parameters have to be specified in the input files of the
Transport module (see Section D.1.3): calibration coefficient α1 , dummy argument, reference
level (bedload layer thickness) or roughness height ξc [m] and settling velocity ws [m/s].

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Soulsby/Van Rijn
The sediment transport relation has been implemented based on the formulations provided in
Soulsby (1997). References in the following text refer to this book.
If the wave period Tp is smaller than 10−6 s, the wave period Tp is set to 5 s and the rootmean-square wave height is set to 1 cm. Furthermore, the wave period is limited to values
larger than 1 s. The root-mean-square wave height is limited to values smaller than 0.4 H ,
where H is the water depth.
The sediment transport is set to zero in case of velocities smaller than 10−6 m/s, water depth
larger than 200 m or smaller than 1 cm.

Urms =

√

πHrms
Tp sinh (kH)

Furthermore, D∗ is defined as (Soulsby, 1997, p.104):

The root-mean-square orbital velocity is computed as:

DR
AF

D.4.7

D∗ =

g∆
ν2

(D.77)

1/3

D50

(D.78)

Using the critical bed shear velocity according to Van Rijn (Soulsby, 1997, p.176):

Ucr =

0.1 10
0.19D50
log (4H/D90 ) if D50 ≤ 0.5 mm
0.6 10
8.5D50 log (4H/D90 ) if 0.5 mm < D50 ≤ 2 mm

(D.79)

larger values of D50 lead to an error and to the halting of the program.

The sediment transport is split into a bedload and suspended load fraction. The direction of
the bedload transport is assumed to be equal to the direction of the depth-averaged velocity
in a 2D simulation and equal to the direction of the velocity at the reference height a (see ??)
in a 3D simulation (Soulsby, 1997, p.183):

Sbx = Acal Asb uξ
Sby = Acal Asb vξ

(D.80)
(D.81)

and the suspended transport magnitude is given by the following formula (this quantity is
lateron converted to a reference concentration to feed the advection-diffusion equation for the
suspended sediment transport as indicated in ??):

√
Ss = Acal Ass ξ u2 + v 2

(D.82)

where

Acal
Asb

a user-defined calibration factor
bedload multiplication factor

Asb = 0.005H
Ass

1.2
(D.83)

suspended load multiplication factor

Ass = 0.012D50

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D50 /H
∆gD50

D∗−0.6
(∆gD50 )1.2

(D.84)

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Morphology and Sediment Transport

a general multiplication factor

r
2.4
0.018
ξ=
U 2 − Ucr
U2 +
CD rms

(D.85)

where U is the total depth-averaged velocity and CD is the drag coefficient due
to currents, defined by:

CD =

κ
ln (H/z0 ) − 1

2
(D.86)

where z0 equals 6 mm and the Von Kármán constant κ is set to 0.4.

The bedslope correction factor is not explicitly included in this formula as it is a standard
correction factor available in the online morphology module. The method is intended for conditions in which the bed is rippled.

D.4.8

DR
AF

The following formula specific parameters have to be specified in the input files of the Transport module (See Section D.1.3): the calibration factor Acal , the ratio of the two characteristic
grain sizes D90 /D50 and the z0 roughness height.
Soulsby

The sediment transport relation has been implemented based on the formulations provided in
Soulsby (1997). References in the following text refer to this book.
If the wave period Tp is smaller than 10−6 s, the wave period Tp is set to 5 s and the rootmean-square wave height is set to 1 cm. Furthermore, the wave period is limited to values
larger than 1 s. The root-mean-square wave height is limited to values smaller than 0.4 H ,
where H is the water depth.
The sediment transport is set to zero in case of velocities smaller than 10−6 m/s, water depth
larger than 200 m or smaller than 1 cm.
The root-mean-square orbital velocity Urms and the orbital velocity Uorb are computed as

Urms =

√

2Uorb =

√
2

πHrms
Tp sinh (kH)

(D.87)

For a flat, non-rippled bed of sand the z0 roughness length is related to the grain size as
(Soulsby, 1997, eq.25, p.48) where χ is a user-defined constant:

z0 =

D50
χ

(D.88)

The relative roughness is characterised using a∗ :

a∗ =

Uorb Tp
z0

(D.89)

which is subsequently used to determine the friction factor of the rough bed according to
Swart (1974) (≡ Equations ??, (D.10) and (D.49)):

fw =

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0.3
if a∗ ≤ 30π 2
−0.19
0.00251 exp (14.1a∗ ) if a∗ > 30π 2

(D.90)

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Table D.8: Overview of the coefficients used in the various regression models (Soulsby
et al., 1993)

1 (FR84)
2 (MS90)
3 (HT91)
4 (GM79)
5 (DS88)
6 (BK67)
7 (CJ85)
8 (OY88)

0.29
0.65
0.27
0.73
0.22
0.32
0.47
-0.06

0.55
0.29
0.51
0.40
0.73
0.55
0.29
0.26

-0.10
-0.30
-0.10
-0.23
-0.05
0.00
-0.09
0.08

-0.14
-0.21
-0.24
-0.24
-0.35
0.00
-0.12
-0.03

-0.77
-0.60
-0.75
-0.68
-0.86
-0.63
-0.70
-1.00

0.10
0.10
0.13
0.13
0.26
0.05
0.13
0.31

0.27
0.27
0.12
0.24
0.34
0.00
0.28
0.25

0.14
-0.06
0.02
-0.07
-0.07
0.00
-0.04
-0.26

Model

DR
AF

which corresponds to formulae 60a/b of Soulsby (p.77) using r = a∗ /(60π) where r is the
relative roughness used by Soulsby. The friction factor is used to compute the amplitude of
the bed shear-stress due to waves as:
2
τw = 0.5ρfw Uorb

(D.91)

Furthermore, the shear stress due to currents is computed as:

τc = ρCD U 2
where

CD =

κ
1 + ln (z0 /H)

(D.92)

(D.93)

as defined on Soulsby (1997, p.53–55). The interaction of the currents and waves is taken
into account using the factor Y in the following formula for mean bed shear stress during a
wave cycle under combined waves and currents (Soulsby, 1997, p.94):

τm = Y (τw + τc )

(D.94)

The formula for Y is given by:

Y = X [1 + bX p (1 − X)q ]
where:

τc
τc + τw

(D.95)

(D.96)

and b is computed using:

b = b1 + b2 |cos φ|J + b3 + b4 |cos φ|J

log (fw /CD )

(D.97)

and p and q are determined using similar equations. In this formula φ equals the angle
between the wave angle and the current angle, and the coefficients are determined by the
model index modind and tables D.8 and D.9 (related to Soulsby (1997, Table 9, p.91)):

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Table D.9: Overview of the coefficients used in the various regression models, continued
(Soulsby et al., 1993)

1 (FR84)
2 (MS90)
3 (HT91)
4 (GM79)
5 (DS88)
6 (BK67)
7 (CJ85)
8 (OY88)

0.91
1.19
0.89
1.04
-0.89
1.14
1.65
0.38

0.25
-0.68
0.40
-0.56
2.33
0.18
-1.19
1.19

0.50
0.22
0.50
0.34
2.60
0.00
-0.42
0.25

0.45
-0.21
-0.28
-0.27
-2.50
0.00
0.49
-0.66

3.0
0.50
2.7
0.50
2.7
3.0
0.60
1.50

Model

Using the shear stresses given above, the following two Shields parameters are computed:

τw
τm
and θw =
ρg∆D50
ρg∆D50

DR
AF

θm =

(D.98)

Furthermore, D∗ is defined as (Soulsby, 1997, p.104):

D∗ =

g∆
ν2

1/3

D50

(D.99)

with which a critical Shields parameter is computed (Soulsby, 1997, eq.77, p.106):

θcr =

0.30
+ 0.055 (1 − exp (−0.02D∗ ))
1 + 1.2D∗

(D.100)

The sediment transport rates are computed using the following formulations for normalised
transport in current direction and normal direction (Soulsby, 1997, eq.129, p.166/167):

Φx1 = 12 (θm − θcr )

p
θm + ε

p
Φx2 = 12 (0.95 + 0.19 cos (2φ)) θm θw + ε
Φx = max (Φx1 , Φx2 )
12 (0.19θm θw2 sin (2φ))
Φy =
(θw + ε)1.5 + 1.5 (θm + ε)1.5

(D.101)
(D.102)
(D.103)
(D.104)

where ε is a small constant (10−4 ) to prevent numerical complications. From these expression
are finally the actual bedload transport rates obtained:

3
g∆D50
(Φx u − Φy v)
p U
3
g∆D50
=
(Φx v − Φy u)
U

Sb,x =

(D.105)

Sb,y

(D.106)

The transport vector is imposed as bedload transport due to currents. The following formula
specific parameters have to be specified in the input files of the Transport module (see Section
D.1.3): calibration coefficient Acal , the model index for the interaction of wave and current
forces modind (integer number 1 to 8) and the D50 /z0 ratio χ (about 12).

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D.4.9

Ashida–Michiue (1974)
The transport rate is given by a generalised version of the Ashida-Michiue formulation:

q
θc
3 m
Sbc = α ∆gD50 θ
1−ξ
θ

r
1−

θc
ξ
θ

!q
(D.107)

where ξ is the hiding and exposure factor for the sediment fraction considered and:

θ=

q 2
C

1
∆D50

(D.108)

Wilcock–Crowe (2003)

The Wilcock-Crowe transport model is a fractional surface based transport model for calculating bedload transport of mixed sand and gravel sediment. The equations and their development are described in Wilcock and Crowe (2003). The bedload transport rate of each size
fraction is given by:

DR
AF

D.4.10

in which q is the magnitude of the flow velocity. The transport rate is imposed as bedload
transport due to currents Sbc . The following formula specific parameters have to be specified
in the input files of the Transport module (see Section D.1.3): α, θc , m, p and q .

Sbi =

Wi∗ Fi U∗3
∆g

(
0.002φ7.5
for φ < 1.35
∗

4.5
Wi =
14 1 − 0.894
for φ ≥ 1.35
φ0.5
τ
φ=
τri

b
Di
τri
=
τrm
Dm
τrm = (0.021 + 0.015 exp (−20Fs )) (ρs − ρw ) gDg
0.67

b=
Di
1 + exp 1.5 − D
g
where:

Di
Dg
Fi
Fs
Sbi
Wi∗
∆
τri
τrm

(D.109)

(D.110)
(D.111)
(D.112)
(D.113)
(D.114)

D50 of size fraction i
geometric mean grain size of whole grain size distribution
proportion of size fraction i on the bed surface
proportion of sand on the bed surface
bedload transort rate of size fraction i
dimensionless bedload transport rate of size fraction i
the relative density of the sediment (ρs − ρw ) /ρw
reference shear stress of grains of size Di
reference shear stress of grains of size Dg

Remarks:
The Wilcock-Crowe model incorporates its own hiding function so no external formulation should be applied.

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The roughness height used for the calculation of grain shear stress during the development of the Wilcock-Crowe transport model was ks = 2D65 .
This sediment transport formula does not have any input parameters that can be, or
need to be, tuned.
D.4.11

Gaeuman et al. (2009) laboratory calibration

The Gaeuman et al. sediment transport model is a modified form of the Wilcock-Crowe model
which uses the variance of grain size distribution on the phi scale (σφ2 ) rather than the fraction of sand on the bed surface (Fs ) as a measure of the bed surface condition for use in
the calculation of reference shear stress. The ’laboratory calibration’ implementation of the
Gaeuman et al. transport model is calibrated to the experimental data used in the derivation
of the Wilcock-Crowe transport model. The model, it’s derivation and calibration is described
in Gaeuman et al. (2009).
The formulae for the calculation of Sbi , Wi∗ , φ and τri are the same as for the Wilcock-Crowe
transport model (Equations (D.109), (D.110), (D.111) and (D.112)) but the calculation of τrm
and b differs.

(ρs − ρw ) gDg

DR
AF

0.015

τrm = θc0 +
1 + exp 10.1σφ2 − 14.14
1 − α0

b=
Di
1 + exp 1.5 − D
g

n
2
X
Di
2
2
log
σφ =
Fi
Dg
i=1

(D.115)

(D.116)

(D.117)

where θc0 and α0 are user specified parameters (See Section D.1.3). If the values θc0 =
0.021 and α0 = 0.33 are specified the original relation calibrated to the Wilcock-Crowe
laboratory data is recovered.
Remark:
The Gaeuman et al. model incorporates its own hiding function so no external formulation should be applied.
D.4.12

Gaeuman et al. (2009) Trinity River calibration

The ’Trinity River calibration’ implementation of the Gaeuman et al. transport model is calibrated to observed bedload transport rates in the Trinity River, USA and is described in Gaeuman et al. (2009). It differs from the ’laboratory calibration’ implementation in the calculation
of τrm and b.

0.022

τrm = θc0 +
1 + exp 7.1σφ2 − 11.786
1 − α0

b=
Di
1 + exp 1.9 − 3D
g

!
(ρs − ρw ) gDg

(D.118)

(D.119)

where θc0 and α0 are user specified parameters (see Section D.1.3). If the values θc0 = 0.03
and α0 = 0.3 are specified the original Gaeuman et al. formulation calibrated to the Trinity
River is recovered.
Remark:

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The Gaeuman et al. model incorporates its own hiding function so no external formulation should be applied.
Morphological updating
The elevation of the bed is dynamically updated at each computational time-step. This is
one of the distinct advantages over an offline morphological computation as it means that the
hydrodynamic flow calculations are always carried out using the correct bathymetry.
At each time-step, the change in the mass of bed material that has occurred as a result of the
sediment sink and source terms and transport gradients is calculated. This change in mass is
then translated into a bed level change based on the dry bed densities of the various sediment
fractions. Both the bed levels at the cell centres and cell interfaces are updated.

Remark:
The depths stored at the depth points (which are read directly from the bathymetry
specified as input) are only updated for writing to the communication file and the result
files.
A number of additional features have been included in the morphological updating routine in
order to increase the flexibility. These are discussed below.

DR
AF

D.5

Morphological “switch”

You can specify whether or not to update the calculated depths to the bed by setting the
BedUpd flag in the morphology input file. It may be useful to turn bottom updating off if
only the initial patterns of erosion and deposition are required, or an investigation of sediment
transport patterns with a constant bathymetry is required.
Remark:
The use of BedUpd only affects the updating of the depth values (at ζ and velocity
points); the amount of sediment available in the bed will still be updated. If you wish to
prevent any change in both the bottom sediments and flow depths from the initial condition then this may also be achieved by either setting the morphological delay interval
MorStt to a value larger than the simulation period, or by setting the morphological
factor MorFac to 0. See below for a description of these two user variables.
Morphological delay

Frequently, a hydrodynamic simulation will take some time to stabilise after transitioning from
the initial conditions to the (dynamic) boundary conditions. It is likely that during this stabilisation period the patterns of erosion and accretion that take place do not accurately reflect
the true morphological development and should be ignored. This is made possible by use of
MorStt whereby you can specify a time interval (in minutes after the start time) after which
the morphological bottom updating will begin. During the MorStt time interval all other
calculations will proceed as normal (sediment will be available for suspension for example)
however the effect of the sediment fluxes on the available bottom sediments will not be taken
into account.

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Morphological time scale factor
One of the complications inherent in carrying out morphological projections on the basis of
hydrodynamic flows is that morphological developments take place on a time scale several
times longer than typical flow changes (for example, tidal flows change significantly in a period
of hours, whereas the morphology of a coastline will usually take weeks, months, or years to
change significantly). One technique for approaching this problem is to use a “morphological
time scale factor” whereby the speed of the changes in the morphology is scaled up to a rate
that it begins to have a significant impact on the hydrodynamic flows. This can be achieved
by specifying a non-unity value for the variable MorFac in the morphology input file.

The implementation of the morphological time scale factor is achieved by simply multiplying
the erosion and deposition fluxes from the bed to the flow and vice-versa by the MorFacfactor, at each computational time-step. This allows accelerated bed-level changes to be
incorporated dynamically into the hydrodynamic flow calculations.

DR
AF

While the maximum morphological time scale factor that can be included in a morphodynamic
model without affecting the accuracy of the model will depend on the particular situation being
modelled, and will remain a matter of judgement, tests have shown that the computations
remain stable in moderately morphologically active situations even with MorFac-factors in
excess of 1 000. We also note that setting MorFac=0 is often a convenient method of preventing both the flow depth and the quantity of sediment available at the bottom from updating,
if an investigation of a steady state solution is required.
Remarks:
Verify that the morphological factor that you use in your simulation is appropriate by
varying it (e.g. reducing it by a factor of 2) and verify that such changes do not affect
the overall simulation results.
The interpretation of the morphological factor differs for coastal and river applications.
For coastal applications with tidal motion, the morphological variations during a tidal cycle are often small and the hydrodynamics is not significantly affected by the bed level
changes. By increasing the morphological factor to for instance 10, the morphological
changes during one simulated tidal cycle are increased by this factor. From a hydrodynamical point of view this increase in morphological development rate is allowed if the
hydrodynamics is not significantly influenced. In that case the morphological development after one tidal cycle can be assumed to represent the morphological development
that would in real life only have occurred after 10 tidal cycles. In this example the number of hydrodynamic time steps required to simulate a certain period is reduced by a
factor of 10 compared to a full 1:1 simulation. This leads to a significant reduction in
simulation time. However, one should note that by following this approach the order
of events is changed, possible conflicts may arise in combination with limited sediment
availability and bed stratigraphy simulations. In river applications there is no such periodicity as a tidal cycle. For such applications, the morphological factor should be
interpreted as a speed-up factor for morphological development without changing the
order of events. Effectively, it means that the morphological development is simulated
using a, for instance 10 times, larger time step than the hydrodynamics, or phrased
more correctly the hydrodynamics is simulated at a 10 times faster rate. This means
that in case of time-varying boundary conditions (e.g. river hydrograph) the time-scale
of these forcings should be sped up: a 20 day flood peak will be compressed in 2 days.
However, one should take care that by speeding up the hydrodynamic forcings one
does not substantially change the nature of the overall hydrodynamic and morphological development: a quasi-steady flood period should not become a short, dynamic flash
flood. For river applications, changing the morphological factor must be associated with
changing all external time-varying forcings. For coastal applications only the overall

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simulation time should be adjusted. Note that the combination of a river-like flood peak
and a tidal motion will cause problems when interpreting morphological factor not equal
to 1.
The effect of the morphological factor is different for bed and suspended load. At each
time step bedload is picked-up from the bed and deposited on the bed: only the transports are increased by the morphological factor used for the time step considered. However, in case of suspended load there is a time-delay between the time of erosion and
the time of deposition. The erosion and deposition fluxes are increased by the morphological factor, but the suspended concentrations are not (since that would influence the
density effects). It is possible to vary the morphological factor during a simulation to
speed up relatively quiet periods more than relatively active periods. Such changes in
the morphological factor will not influence the mass balance of a bed or total load simulation since pickup and deposition are combined into one time step. However, in case
of suspended load the entrainment and deposition may occur at time-steps governed
by different morphological factors. In such cases the entrainment flux that generated a
certain suspended sediment concentration will differ from the deposition flux that was
caused by the settling of the same suspended sediment. A change in morphological
factor during a period of non-zero suspended sediment concentrations, will thus lead to
a mass-balance error in the order of the suspended sediment volume times the change
in morphological factor. The error may kept to a minimum by appropriately choosing the
transition times.

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Photo’s by: BeeldbankVenW.nl, Rijkswaterstaat / Joop van Houdt.

PO Box 177
2600 MH Delft
Rotterdamseweg 185
2629 HD Delft
The Netherlands

T +31 (0)88 335 81 88
F +31 (0)88 335 81 11
sales@deltaressystems.nl
www.deltaressystems.nl

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