Unibest Cl - Manual

Prepared for:

UNIBEST CL+ 6.0, August 2005

User & Theoretical Manual

wl| delft hydraulics Jan Kramer

Report September, 2005

Title X0000.00 September, 2005

Contents

UNIBEST CL+ 6.0, August 2005 ..........................................................................................1

1 Introduction...............................................................................................................1

1.1 Unibest...........................................................................................................1

1.1.1 Applicability of UNIBEST-CL+.......................................................1

1.1.2 Upgrade summary.............................................................................2

1.1.3 How to read this manual ...................................................................3

1.1.4 Installation of the program................................................................3

1.1.5 Windows settings for UNIBEST CL+ ..............................................3

1.1.6 Starting the program .........................................................................4

1.1.7 Acknowledgements...........................................................................4

2 Definition of model entities and concepts ...............................................................5

2.1 Introduction....................................................................................................5

2.2 Basic modelling concepts ..............................................................................5

2.3 The curved coordinate system .......................................................................6

2.4 The Basic MODEL ........................................................................................6

2.5 Transport Rays...............................................................................................7

2.6 LT-Run specifications ....................................................................................9

2.6.1 Wave and Current Scenario ............................................................10

2.6.2 A Cross-Shore Profile .....................................................................11

2.7 Global and Local Transports........................................................................12

2.8 Boundary Conditions ...................................................................................13

2.9 Optional Model Entities...............................................................................13

2.9.1 Groynes...........................................................................................14

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2.9.2 Offshore breakwaters......................................................................17

2.9.3 Revetments .....................................................................................17

2.9.4 Sources and Sinks ...........................................................................18

2.9.5 Internal Boundaries.........................................................................18

2.10 The screen lay-out........................................................................................18

2.11 A Phase Model .............................................................................................19

2.12 The CL-Run Specification ...........................................................................19

3 Data structure and processing steps......................................................................20

3.1 List of UNIBEST-CL+files..........................................................................20

3.2 Output ..........................................................................................................21

3.3 Post-Processing utilities...............................................................................22

4 The User Interface ..................................................................................................23

4.1 Window conventions ...................................................................................23

4.2 Model Management .....................................................................................23

4.2.1 Process flow....................................................................................27

4.3 LT Input and Output.....................................................................................29

4.3.1 LT input: .........................................................................................29

4.3.2 LT Runs and Output........................................................................37

4.4 CL input .......................................................................................................44

4.4.1 The Basic Model.............................................................................45

4.4.2 Global Transport .............................................................................46

4.4.3 Boundary Conditions ......................................................................49

4.4.4 Case definition ................................................................................52

4.4.5 Optional Model Entities..................................................................58

4.4.5.1 Groynes...........................................................................................58

4.4.5.2 Offshore Breakwaters .....................................................................61

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4.4.5.3 Revetments .....................................................................................64

4.4.5.4 Sources and Sinks ...........................................................................67

4.4.5.5 Internal Boundaries.........................................................................69

4.5 The Run Option ...........................................................................................71

4.5.1 Running the LT-module ..................................................................71

4.5.2 Running the CL-Module.................................................................72

4.5.3 Run Volumes...................................................................................73

4.5.4 Inspect Run Reports........................................................................74

4.6 Options.........................................................................................................81

5 Tools .........................................................................................................................83

5.1 Unibest CL+ & Delft3D-Wave ....................................................................83

5.1.1 Interface ..........................................................................................83

5.1.2 DELFT3D-WAVE: Link between Unibest and Delft3D to define and run 2D wave model .......................................................83

5.1.3 LOCAL SCENARIO FILES: Link to select relevant wave data from the HWGXY/WAVM file.......................................................86

5.2 Unibest CL+ & Flow ...................................................................................87

5.3 Unibest CL+ & ARGOSS............................................................................87

5.3.1 Introduction.....................................................................................88

5.3.2 Request for (a) wave climate(s) ......................................................88

5.3.3 Initialisation ....................................................................................89

5.3.4 Requests with program DelftClimSAT ...........................................89

5.3.4.1 Start the program within UNIBEST CL+ Graphical User Interface ..........................................................................................89

5.3.4.2 Start the program without UNIBEST CL+ Graphical User Interface ..........................................................................................90

5.3.4.3 Fill in the form for request..............................................................91

5.3.5 Status of the requests with program DelftClimSAT .....................102

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5.3.5.1 Start the program within UNIBEST CL+ Graphical User Interface ........................................................................................102

5.3.5.2 Start the program without UNIBEST CL+ Graphical User Interface ........................................................................................102

5.3.6 Transform ARGOSS climates.......................................................108

6 Theoretical Manual...............................................................................................109

6.1 Introduction................................................................................................109

6.2 Capabilities of UNIBEST ..........................................................................110

6.3 Short description of UNIBEST..................................................................111

6.3.1 Unibest LT ....................................................................................111

6.3.2 Unibest CL....................................................................................112

6.4 Basic assumptions of single-line theory ....................................................113

6.5 Required data to run UNIBEST.................................................................116

6.5.1 General..........................................................................................116

6.5.1.1 Waves:...........................................................................................117

6.5.1.2 Water levels: .................................................................................118

6.5.1.3 Currents: .......................................................................................118

6.5.1.4 Nearshore topography...................................................................118

6.5.1.5 Littoral drift: .................................................................................119

6.5.1.6 Sediment: ......................................................................................119

6.5.1.7 Rivers and other:...........................................................................119

6.6 Mathematical physical description ............................................................119

6.6.1 Basic assumption ..........................................................................119

6.6.2 Governing equations.....................................................................120

6.6.2.1 Wave propagation and breaking....................................................120

6.6.2.2 Currents ........................................................................................123

6.6.2.3 Sediment transport ........................................................................124

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6.6.2.4 Coastline evolution .......................................................................125

6.7 Schematizations and approximations.........................................................126

6.7.1 The sediment transport as function of the coastangle...................126

6.7.1.1 The sediment area and dynamics area ..........................................127

6.7.1.2 The by-pass transport at groynes ..................................................128

6.8 Numerical solutions ...................................................................................129

6.8.1 Cross shore equations ...................................................................129

6.8.2 Coast line equations......................................................................130

6.8.2.1 Groynes.........................................................................................132

6.8.3 Revetments ...................................................................................134

6.8.4 Numerical solution........................................................................135

6.8.4.1 The linearization ...........................................................................136

6.9 Modelling of beach line developments behind offshore breakwaters and groynes................................................................................................136

6.9.1 Introduction...................................................................................136

6.9.2 Coefficients of local transport table..............................................137

6.9.2.1 Application of STRUCT program ................................................138

6.9.2.2 Application of diffraction diagrams SHORE PROTECTION MANUAL 1984............................................................................139

6.10 Modelling cases (Based on DOS version) .................................................142

6.11 Future developments of UNIBEST............................................................143

6.12 Longshore transport formulae....................................................................143

6.12.1 Bijkers’s formula ..........................................................................143

6.12.2 Formula of Engelund-Hansen.......................................................145

6.12.3 Formula of Van Rijn .....................................................................146

6.12.4 Formula of CERC.........................................................................149

6.12.5 Formula of Bailard........................................................................150

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6.12.6 Longshore transport of coarse materials .......................................152

References ...............................................................................................................154

A APPENDIX A .......................................................................................................A–1

B APPENDIX B .......................................................................................................B–1

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Introduction 1

Copyright Information Copyright © DELFT HYDRAULICS 1999 All rights reserved This software and the documentation is furnished under license and may be used only in accordance with the terms of such license. In summary, DELFT HYDRAULICS grants the licensed user the non-exclusive and non-transferable right to use the software. The user has NO ownershiprights or authorright and may not make any alterations. The user is liable for a responsible application of the software. It is advised to consult the User's manual before applying the software. All intellectual property rights necessary to license Unibest CL+ to you ("Licensee") are vested in DELFT HYDRAULICS. DELFT HYDRAULICS shall not be responsible for losses of any kind resulting from the use of Unibest CL+ or of any documentation and can in no way provide compensation for any losses sustained including but not limited to any obligation, liability, right, claim or remedy for tort nor any business expense machine downtime or damages caused to Licensee by any deficiency defect or error in Unibest CL+ or in any such documentation or any malfunction of the Unibest CL+ or for any incidental or consequential losses damages or costs however caused.

1.1 Unibest

The UNIBEST software suite is an acronym of Uniform Beach Sediment Transport. It has been developed by WL|DELFT HYDRAULICS in order to yield an integrated package with diagnostic capabilities in the study and simulation of longshore and cross-shore processes and related morphodynamics of beach profiles and beach planform shapes (coastline evolution). The UNIBEST software suite consists of two separate modules: UNIBEST-TC: Designed for the computation cross-shore transport and resulting beach

changes induced by waves, tidal currents and wind. UNIBEST-DE: Designed for the computation of dune erosion during storm conditions. UNIBEST-CL+: Designed for the simulation of coastline changes due to longshore sediment

transport gradients. The longshore transports are induced by tide and wave driven longshore currents.

The integrated UNIBEST coastal software suite constitutes a very powerful but easy to operate coastal engineering tool in coast erosion control and management. This manual gives you the background and in-depth explanations of the options and operation of the UNIBEST-CL+ module. For a description of the underlying theories is referred to WL|DELFT HYDRAULICS (1992). A description of UNIBEST-TC can be found in Bosboom et al. (1997) and WL|DELFT

HYDRAULICS (1999). For a description of UNIBEST-DE reference is made to Steetzel (1993).

1.1.1 Applicability of UNIBEST-CL+

UNIBEST-CL+ consists of two integrated sub-modules: • The Longshore Transport module (LT-module) • The CoastLine module (CL-module)

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The required longshore sediment transports are computed with the LT-module. These transports are used by the CL-module to perform coastline evolution simulations in which effects of structures such as groynes, offshore breakwaters and revetments can be incorporated.

Longshore Transport (LT) module

The LT-module is designed to compute tide- and wave-induced longshore currents and sediment transports on an alongshore uniform beach with an arbitrary profile. The surfzone dynamics are derived from a built-in random wave propagation and decay model, which transforms offshore wave data to the coast taking the principal processes of linear refraction and non-linear dissipation by wave breaking and bottom friction into account. The longshore sediment transports and cross-shore distribution are evaluated according to various transport formulas, which enables a sensitivity analysis for local conditions. The computational procedure may take any pre-defined wave climate and tidal regime into account in order to enable an assessment of gross and yearly longshore transports, seasonal variation and even storm events.

CoastLine (CL) module

The CL-module is designed to simulate coastline changes due to longshore sediment transport gradients of an alongshore nearly uniform coast, on the basis of the single line theory. Various initial and boundary conditions may be introduced as to represent a variety of coastal situations. Along the modelled coastline sediment sources and sinks may be defined at any location, to cater for river sediment yield, subsidence, offshore sediment losses, beach mining, etc. Furthermore, it is capable of modelling the morphologic effects of various coastal engineering measures, such as headlands, permeable and non-permeable groynes, coastal revetments and seawalls, breakwaters, harbour moles, river mouth training works, artificial sand by-pass systems and beach nourishments. The effect of wave shielding (diffraction, directional wave spreading) behind coastal structures can also be incorporated in the model. The model can be used for the conceptual design (location, dimensions and spacing) of coastal structures and the impact assessment on adjacent coastal stretches. The actual longshore transports along the considered coastline are computed with the LT-module. This allows for a very flexible model set-up in which coastal structures or natural phenomena can easily be incorporated.

1.1.2 Upgrade summary

The main differences between Version 6.X and Version 3.xx (which is the previous commercial version of UNIBEST) are: • UNIBEST-CL+ (Version 6.X) has been developed for the Windows operating systems



• UNIBEST-CL+ (Version 6.X) is an integration of the longshore transport module LT and the coastline module CL.

• The coastline module CL+ in UNIBEST-CL+ (version 6.0 or higher) is based on a curved co-ordinate system along the coast, which enables the modelling of larger coastal areas. Even almost fully developed isles are possible.

• UNIBEST-CL+ (Version 6.X) offers more sophisticated options for defining local wave climates and transports with respect to groynes and offshore breakwaters.

• UNIBEST-CL+ (Version 6.X) can be easily linked to Delft3D-Wave, to model wave propagation in a sophisticated way (for example around structures) and to transform the results of Delft3D-Wave computations to nearshore wave climate tables suitable for longshore transport runs. Since this option is only functional in combination with certain modules of the Delft3D package, it is not delivered as a standard functionality. For users who also have purchased the required Delft3D modules, this option can be activated. A description of how this link works can be found in Section 5.1.

• UNIBEST CL+ (Version 6.X) offers the possibility (if licensed) to create input files for the Delft3D FLOW modul. However this tool is still in development phase and there for not sold commercially yet.

• UNIBEST CL+ (Version 6.X) offers the possibility (if licensed) to retrieve wave information from ARGOSS database, see Section 5.3 for a description on how to do this. For more information on ARGOSS see webpage www.waveclimate.com.

1.1.3 How to read this manual

The manual is organised as follows: • In Chapter 2 the various model entities and model concepts are defined and explained. • Chapter 3 describes the implementation of the entities and concepts in data structures and

modelling and processing steps. Also the output is explained here. • Chapter 4 explains the operation and options of the User Interface. • Chapter 5 explains how to use the tools available (if licensed) in Unibest CL+. • Chapter 6 describes the theoretical background of Unibest CL+. • Appendices A and B describe two cases which have been modelled by using DOS versions

of Unibest CL, Unibest LT and Unibest TC. • Appendix C, gives an overview of seversal array bound values.

1.1.4 Installation of the program

For how to install Unibest CL+ on your PC read the README file (Readme_Unibest.PDF). This file contains the bug fixes with respect to the previous versions also.

1.1.5 Windows settings for UNIBEST CL+

For correct functioning of the UNIBEST-CL+ software the decimal separator has to be set to “.”. You can set this by selecting the “control panel” from the Settings menu under START. In the “control panel” select “regional settings” and go to tab “Number”. Here you can set the decimal separator.



1.1.6 Starting the program

You can start the program by subsequently selecting: Start|Programs|Delft-Chess|Unibest CL + [version number]|Unibest CL+ [version number] or double click the Unibest CL+ icon on your desktop or go to the installation directory and double click the program Unibest6.exe.

1.1.7 Acknowledgements

MS-DOS, Windows, Windows 95, Windows 98, Windows NT, Windows Millennium, Windows 2000 and Windows XP are trademarks of Microsoft Corporation. Microsoft Visual Basic 6.0 (SP5) is a product of Microsoft Corporation Microsoft Visual C++ 6.0 is a product of Microsoft Corporation SPREAD32 is a product of Farpoint Technology Inc. FLEXLM is a product of Macrovision.



Definition of model entities and concepts 2

2.1 Introduction

Before going into the details of setting up an UNIBEST-CL+ coastline model the basic concepts on which UNIBEST-CL+ is based are described. Please make yourself familiar with these concepts and the schematisations that are described in Chapter 2, as they are essential for a good understanding of how to operate and set-up a coastline model with UNIBEST-CL+. After describing the basic modelling concept of UNIBEST-CL+ in Section 2.2 the co-ordinate system is explained in Section 2.3. The Basic Model, which defines the coastline, is described in Section 2.4 The concept of the Transport Ray is treated in Section 2.5. In Section 2.6 the input for a longshore sediment transport is discussed. In Section 2.7 the concept of global and local transports in UNIBEST-CL+ is described. Section 2.8 deals with the boundary conditions. In Section 2.9 the additional conditions such as groynes, offshore breakwaters, etc. are treated. The screen layout is discussed in Section 2.10. Finally, the phase definitions in a simulation and the CL-run specification are described in Section 2.11 and Section 2.12.

2.2 Basic modelling concepts

UNIBEST-CL+ consists of two integrated modules: • the LT-module which calculates the longshore sediment transports induced by waves

and tidal currents, • the CL-module which uses the results from LT-simulations to simulate the development

of the coastline under the influence of the computed longshore gradients along the considered coast.

All input and output files of the two modules are in ASCII-format. The communication between the two modules is based on these files. This gives (experienced) users the opportunity to make modifications to a model on file-level with an arbitrary ASCII-editor. Often this feature is used to automatically generate wave and current boundary conditions for various LT-simulations along a coast based on wave and tide area model simulations (e.g. with DELFT3D-WAVE and DELFT3D-FLOW). All files are ‘free-formatted’. This implies that the appropriate data only has to be placed on the correct lines in a file, the actual format of the numbers and the spacing is irrelevant. The file-formats are not explained in this manual but the various demonstration models that are shipped with UNIBEST-CL+ can be used as an example. The CL-module simulates the coastline evolution based on the longshore transport gradients that are present along the considered coast. These longshore transport gradients are derived from longshore transport calculations performed with the LT-module. The results of an LT- calculation have been transformed to a function that describes the integrated longshore transports as function of the coastline orientation. Relevant information for the so-called



transport function is stored in the RAY-files. At different locations along the coast the user can prescribe specific transport functions. The user does not have to define these functions at every computational grid point. Internally a linear interpolation will be performed between the prescribed transport functions. During a coastline simulation with the CL-module the actual transport rates are derived from the transport functions based on the actual coastline orientation. This enables a very computer efficient calculation. If due to accretion or erosion the coastline orientation changes with time, the longshore transports will also change. Furthermore this method has the advantage that the impact of structures can easily be incorporated in the coastline model by inserting local transport functions. The incorporation of wave diffraction behind an offshore breakwater on the longshore sediment transport is such an example.

2.3 The curved coordinate system

In Version 3.0 the co-ordinate system was a rectangular system defined by a coastal co-ordinate axis x and a coastline axis y perpendicular to it. The user had to define the x-axis in accordance with the coast section he wanted to model. All angles of waves and bathymetry had to be transformed to that co-ordinate system. In Version 6.X the x-axis is a curved line, and the y-direction is defined by the normals perpendicular to it. This curved system can be placed in the "real world" of the project world co-ordinates (xw,yw) system ( ). For wave angles the usual north-orientated definition is used. The positioning of objects (groynes, sources etc.) can be done in world co-ordinates. The program will internally interpolate these objects to the computational grid points.

Figure 2.1

Figure 2.1, Curved co-ordinate system

2.4 The Basic MODEL

The Basic Model (which defines the actual coastline) consists of: • The curved x,y system.



• The y(x) initial coastline. • The grid points along the curved x-axis (y=0). You can create the curved x-axis by defining a number of Basic Points (Figure 2.2). The program fits a curved line through the Basic Points using a local third-degree interpolation with continuous first derivatives at the Basic Points. At these points you should also define the coastline position y, which are the Basic y-points. At the basic points and at a user-defined number in between, x-grid points (briefly named x-points) are created. At x-points the transport rate Qs is defined.

Figure 2.2, The Basic-Model

Halfway between the x-points, the xy-points (i.e. points where the coastline y is defined) are located. The y-value at the xy-points is obtained by linear interpolation between the Basic Y-points, assuming the (x,y) system to be a rectangular co-ordinate system ( ). Figure 2.3

Figure 2.3, Grid points definition

2.5 Transport Rays

A Transport Ray is the result of a longshore sediment transport calculation with the LT-module based on a coastline orientation, a prescribed wave and current climate and a bottom profile. Basically a Transport Ray is a transport function which defines the longshore sediment



transport as a function of the coastline orientation. Transport Rays are used as input for the CL-module to determine the actual longshore transports based on the calculated coastline orientation. Transport Rays are used to define Global and Local Transport properties along the model grid points. More specific, a Transport Ray is defined by the following transport properties (see also Figure 2.4 to ): Figure 2.6 • The angle of the coastal orientation upon which the cross-ray is defined. In UNIBEST the

coastal orientation is expressed as the direction of the seaward directed coast-normal, measured clockwise relative to the North, as illustrated in Figure 2.4.

• Coefficients defining the transport rate as a function of the actual coastline orientation (describing the transport function Qs = f(αe,c1,c2)).

• The characteristic points xrb, xr

2%...xr100%, with respect to the coastal point xr

c. These points define the cross-shore integrated transports percentages which are used to determine the sediment by-pass in case of groynes, see Figure 2.4 and Figure 2.5. The xr

c point in the coastal profile determines the location in the coastal profile and thus the depth contour that corresponds with the Y-values in the shoreline model (see Section 2.4).

• The profile height as defined by the user, see Figure 2.6. • The profile shape factor γ.

Figure 2.4, Transport Ray definition



Figure 2.5, Characteristic-points

Figure 2.6, Profile-shape factor

2.6 LT-Run specifications

The input for an LT-run calculation step is: • a wave-and-current scenario (definition wave angles with respect to the north), • the coastal orientation angle (with respect to world co-ordinates), • a cross section (perpendicular to coastal angle), • a selected transport formula and the required coefficients, • coefficients for the energy decay calculation. In an LT-run any number of LT-calculation steps resulting in Transport Rays can be performed. A LT-calculation runs as follows: • Making an estimate of the equilibrium angle (the rotation of the coast, where Qs = 0),

based on a simplified method.



• For a number of angles around the equilibrium angle (−60 degrees, +60 degrees) the calculation of the Total Transport Qs for all wave/current combinations of the Wave-and-Current Scenario.

• By using the least-square method the function becomes (Figure 2.7): Qs(θ)= c1.θr.exp{ – ( c2.θr )2} Where θr = θ − θe , with θ = the actual coast orientation and θe = the equilibrium angle, the coast angle for which Qs = 0. By using the option "LT-interactive", you can also execute the steps listed above one by one and inspect the results of the individual coastal rotations. The simplified method, which is used for the estimation of the balanced angle (and of the effect of the current), is used as follows: For each combination of wave-and-current a ‘one-wave’ approximation: is made, where: θn = θ – θw and: θw is the wave angle with respect to the coastal normal.

Figure 2.7, Equilibrium angle (θe) is approximated by: θw + c2i/c1

i

2.6.1 Wave and Current Scenario

The Wave Scenario is defined by a sequence of wave conditions. The current scenario is defined by a sequence of flow conditions. Wave Scenario input: • significant wave height (at the seaward boundary of the cross-shore profile), • water level, • peak period, • wave angle with respect to the north (Figure 2.8), • duration.

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Current Scenario input: • tidal surge, • tidal flow velocity, • reference depth (this is the depth at which the tidal velocities are valid), • percentage of duration. Each condition from the Wave Scenario is combined with all the conditions in the Current Scenario. The duration of a combination is the product of the wave duration and the percentage of occurrence of the current condition. The total of the percentages in the Current Scenario must be 100%. The wave conditions are used as a boundary condition at the sea boundary of a cross-shore profile defined along the normal of a coast section. Waves from directions outside the domain (–90o, 90o) with respect to the coast normal are neglected if the current is zero. The current conditions are translated via the Chézy-relation to a surface slope term in the long-shore velocity equation. Because the transport formulas are based on a combination of waves and current, in the case of no offshore wave the current is combined with a wave of 0.02 metres perpendicular to the coast.

Figure 2.8, Definition wave angle

2.6.2 A Cross-Shore Profile

A Cross-Shore Profile is defined by a sequence of bottom heights (Figure 2.9). The x-co-ordinate is written as xr. The co-ordinate xr

b divides the profile in two parts, i.e. a static part (outside the transport zone) and a dynamic part. The dynamic part is supposed to rotate in the same way as the coastline. At the coastal side the point xr

c indicates the position in the cross-shore profile that coincides with the coastline position Y in the Coastline Model. By defining the point xr

1 inside the dynamic area, you can cut off the sediment area if necessary.



Figure 2.9, Cross-shore profile

2.7 Global and Local Transports

The Global Transport defines transport properties at each x-grid point (the Qs definition points) along the curved model axis. These properties consist of the transport coefficients, the profile height and the characteristic points along the coastal normal. The Global Transports basically describe the transport along an undisturbed coastline. Additional conditions (e.g. structures) often involve the description of Local Transports. These Local Transports then overwrite the Global Transports locally. You must define the Global Transports by inserting one or several Transport Rays (at reference points in world co-ordinates) along the coast. The equilibrium angle αe is now redefined by the program with respect to the coastal angle that stands perpendicular to the coastal normal. At the Qs-grid points the transport coefficients and characteristic points are determined by linear interpolation with respect to the x-values (Figure 2.10). Beyond the definition area the data remain constant, which means that αe remains constant. In y-direction the coastal point xr

c will coincide during the calculation with the current Y-position of the coast. Local Transport sections (related to Groynes and Offshore breakwaters) can overrule the Global transport.



Figure 2.10, Interpolation transport properties

2.8 Boundary Conditions

Boundary Conditions are the conditions that describe the behaviour of the coast at the two model boundaries in terms of the coastline position Y, the transport Qs or the coastal angle. There are four options: • the coastline position y remains constant, • the coastal angle remains constant (this implies that the transport at the boundary is kept

constant), • the transport Qs is a user-defined constant value, • the transport Qs is a user-defined function of time. The Basic Model with Global Transports and Boundary Conditions will make an executable model. Additional conditions can be` added but are not strictly required. These additional conditions can be a combination of: groynes, offshore breakwaters, revetments, sources and sinks and internal boundaries. These are described in the following section.

2.9 Optional Model Entities

Additional conditions can be: • groynes (with Local Transports) • offshore breakwaters (with Local Transports) • revetments • sources and sinks • internal boundaries



2.9.1 Groynes

A groyne is defined by (Figure 2.11 and Figure 2.12): • the position in x-direction, • the position of the top in y-direction, • the percentage of blocking (in order to enable the modelling of permeable groynes). The position in x-direction is given as a reference point in world co-ordinates. As in the program a groyne must be located at an x-grid point (points where Qs is defined), the program will map the position to the nearest x-grid point.

Figure 2.11, Groyne mapping at grid

The top position can be defined in two ways: 1. absolute, as the length from the reference point to the top; 2. relative, as the length from the coastline position y at the start of a CL-calculation phase to

the top.



Figure 2.12, Groyne definition

It is possible to define local transport properties at the left and/or right side of a groyne or in between two groins (Figure 2.13). For that purpose the user can insert a series of Transport Rays at those locations (i.e. inserting Local Transports). The transport coefficients at the x-grid points are obtained by linear interpolation between the Ray data. The shift of the groyne co-ordinate in x-direction to match an x-grid point, is also applied on the x-position of the Transport Rays, to maintain the relation between Groyne and Transport Rays. In case of a series of Transport Rays between two groynes, the shift-value will vary linearly from that of the left groyne to that of the right groyne. The x-grid points for which Local Transports will be prescribed (i.e. the impact area of the series of Transport Rays) will be limited to the points that are enclosed by the prescribed Transport Rays. For the section between a groyne and a Transport Ray the impact area will always include the point next to the groyne (see also Figure 2.13). The x-grid point of the groyne itself will never be modified.



o local transports are valid ∆ global transports are valid

Figure 2.13, Impact area Local-Transport at a groyne

However, it should be realised that the transport properties of the groyne-grid point itself will only be used in the case of an inactive groyne (covered by sand). At an active groyne, either the left properties or the right properties will be applied, depending on the transport direction (see also Figure 2.14). For detailed wave modelling around groynes reference is made to Section 4.4.5.1 and Section 6.8.2.1

Figure 2.14, Groyne mechanism



2.9.2 Offshore breakwaters

The effect of an offshore breakwater can be simulated by a series of Transport Rays describing the Local Transports behind the breakwater. The breakwater itself, defined as a polygon, has no influence on the calculation. The transport coefficients at the x-grid points are obtained by linear interpolation between the Ray data. The x-grid points for which the transport properties will be modified, the impact area of the series of Transport Rays, will be limited to the area enclosed by the prescribed Transport Rays (Figure 2.15). For detailed wave modelling around offshore breakwaters reference is made to Section 4.4.5.2.

Figure 2.15, Impact area local Transport Rays

2.9.3 Revetments

You can define revetment sections along the coast. A revetment protects the coast against erosion beyond a fixed y-position. A revetment section is defined by means of a polygon of reference point locations (in world co-ordinates) and y-distances to define the front position at those locations (Figure 2.16). The front position can be defined in two ways: 1. absolute, as the length from the reference point to the front position, 2. relative, as the length from the coastline position y at the start of a CL-calculation phase to

the front position. The initial y-value of the model should not be less than yF+δ, where yF is the front position of the revetment and δ is a layer thickness of 1 m. Within this layer the erosion gradually reduces to zero. The revetment is numerically active at the xy-points inside the revetment section. The yF-value there is obtained by linear interpolation in the yF(x) function. For detailed wave modelling around revetments reference is made to Section.4.4.5.3 and Section 6.8.3



Figure 2.16, Revetment definition

2.9.4 Sources and Sinks

The user can define sources and sinks of sand. It may be either a constant value or a tabulated function in time. The location is defined by the co-ordinates of a reference point. The source or sink should numerically be defined in a xy-point, so the program will map the location on the nearest xy-point.

2.9.5 Internal Boundaries

Apart from the absence of Local Transports, internal boundaries are like groynes. The calculation rules and definition parameters are the same. They can be used for the modelling of discontinuities. By using a 0% blocking percentage and a large length, transport can pass, but the magnitude is determined by the coastal angle of the ‘upstream’ side.

2.10 The screen lay-out

You can define a number of graphic objects to be plotted on the screen additional to the coastline of the model. Moreover, the initial view port on the model is defined here. Compulsory items in the screen lay-out file are: • the definition of the initial view port, • the object: Land Polygon. The Land Polygon is a polygon connecting the last point of the coastline to the first one. That makes the polygon a closed polygon and enables it to be filled with a colour. Other objects can be (optional): • polygons to define lines or areas on the land or in the sea



• text labels • circles to define cities etc. When the Basic Model is defined and a user lay-out does not exist, a default lay-out is produced by the program. The default lay-out contains, apart from the compulsory items, some examples of the additional objects. You can use these default layouts to modify them to your own wishes. All information in the screen layout is purely cosmetic. It has no influence on the results of the calculation.

2.11 A Phase Model

The Basic Model in combination with a set of Global Transports, a set Boundary Conditions and a set of Additional conditions, will be called a Phase Model, which can be applied during a Phase of the time domain of a coastline simulation (see also next section).

2.12 The CL-Run Specification

The time domain of a run can contain one or several time phases (Figure 2.17). In a time phase a ‘Phase Model’ is active. A number of time phases together will be named a cycle. A cycle can be repeated one or more times. This offers the possibility to have a sequence of different global transports, boundary conditions and additional conditions in one run, for instance to simulate the various seasons of a year. You select the time unit you want to use (year, month, day, etc.) for the definition of start time, time-step and the duration of the time phases. You can also define the time points where output is requested.

Figure 2.17, Scheme of CL-Run specification



Data structure and processing steps 3

3.1 List of UNIBEST-CL+files

The data pertaining to the entities and concepts discussed in Chapter 2 are stored in separate ASCII-files, each file with its own extension. The relation between entity and file extension is given below. In Figure 3.1 a data flow diagram is shown. Longshore Transport (LT) calculations: Entity file extension Wave Scenario SCO Cross Section (Profile) PRO Coefficients Energy decay CFE Coefficients Sediment transports CFS An LT-run specification LTR An output report of an LT-run (log-file) GLO Transport Ray (result-file used by CL-module) RAY Coast Line model (CL) calculations: Entity file extension Basic Model MDA Global Transports GKL Boundary conditions BCO Groynes (with local transports) GRO Offshore breakwaters (with local transports) OBW Revetments REV Sources and sinks SOS Internal boundaries BCI Layout LAT A CL-run specification CLR A CL-run output report PRN A CL-run documentation report DES Interface file to GIS-system (optional) GIS Postprocessing VOLUMES-run Entity file extension A Volume Run output report VOL



Figure 3.1, Data structure of UNIBEST-CL+ V5 or higher

3.2 Output

The output of a LT-run consists of one or several RAY-files and GLO-files. The RAY-files can be input for the definition of Global or Local Transport properties in the CL-module; they have been discussed before. A GLO-file contains a report of the calculations resulting in the information on a RAY-file. Apart form the output to file, you can request for various plots on the screen. The output of a CL-run consists of: • A report file (extension PRN) with output at a number of time points during the process.

You can define the output-time points beforehand at the CL-run specifications, and can request for output during a process interrupt.

• A report file (extension DES) with information about the CL-run specifications. Moreover, the history of the RAY-files is traced as much as possible.

• The coastline plot on the screen during the whole process (with zoom option). • Graphic and tabulated transport properties at request of the user. The contents of report files and graphic information will be explained in greater detail in the description of the User Interface (Chapter 4).



3.3 Post-Processing utilities

There is a post-processing program available that works on a PRN-file, for the calculation of volumes in user-defined time/place window. You can define the window by entering two x-grid points numbers and the number of two of the available time points on the PRN-file. The program calculates the passed volumes through the x-borders and the stored volumes at the t-borders of the window. Moreover, the integrated sources/sinks are calculated. If you wish so, the output can be written to a VOL-file.



The User Interface 4

4.1 Window conventions

We assume you to be familiar with Windows. All the controls operate according to the standard Windows conventions and are not explained here. If you are unfamiliar with these conventions we suggest that you consult the appropriate documentation of your Operating Software.

4.2 Model Management

After starting the program you can select Model manager from the main menu. If you wish to work with a model you can either select an existing model by choosing Model selection, or create a new one by choosing: Create Model.

Figure 4.1

For each Model of UNIBEST-CL+ (Version 6.X) the Model Manager will create its own Sub-Directory under the Directory UB. The figure below clarifies this.

Directory

UB

Models (Sub-directory)

Model A

Model B

Model C

Model B



A Model consists of one Basic Model (i.e. one coastline) with the LT-Runs and CL-Cases related to that Basic Model. So it is possible to have various runs in one model-directory. However, there can only one coastline and associated computational grid (i.e. Basic Model) be used in a model directory. If you choose Model Selection ( ) you will get a list of all existing models. After the selection of a Model all Model options will be activated. The selected model is now the Current Model.

Figure 4.2

Figure 4.2

With the option Delete Model you can delete complete Models.

Figure 4.3



If you choose menu option Create Model, UNIBEST-CL+ will ask you to enter a Model name. After that, all Model options will be activated. The created model is now the Current Model. A number of default LT- and CL-files is created at the same time with the model creation. LT-default files: def-bij.cfs, def-cer.cfs, def-gra.cfs, def-rij.cfs, defaults.cfe CL-default files: fixed.bco, <model>.dim, null.bci, null.gro, null.obw, null.rev, nul.sos, zero.bco

Figure 4.4

With the Copy option you can copy entities (files) from other Models to the Current Model. When you select the source Model you will get a list of all available files. The Model Manager offers you three options: All, LT, and Select. This means that you can copy either all files from the source model or only the LT-Files, or you can choose the files you wish to copy from a list of all available model files. If you copy the unique basic-Model-file (named: <source-Model>.MDA) and you have already a MDA-file, you will be warned that an overwrite may occur. If an MDA-file does not yet exist, the copied file will get the name: <current Model>.MDA. (Note: the MDA and the DIM file should always have the name of the “current model”. This is the name of the sub-directory containing the model files).



Figure 4.5

You can also delete files from the Current Model by selecting the Delete option. The Model Manager then shows you a list of all model files from which you can make your choice of the files you wish to delete.

Figure 4.6

You can use the option Export Model to write a Model to a diskette or to another directory outside the work domain of the Model Manager, in order to be used on another computer or by another person. With the option Import model you can import a Model from outside the domain of the Model Manager.



4.2.1 Process flow

Before we begin describing the User Interface options, first we give a description of how the process is progressing. On various levels a Window User Interface offers access to the different parts of the program, but when building a coastline model one has to follow a certain sequence of actions. It may not be possible to execute a process step if the required data are not yet available.

Figure 4.7

The data flow diagram above, which has to be read from top to bottom, offers some help. Briefly, the process is as follows:



LT-run

You can execute an LT-run (via batch or interactively) with as a result one or more Transport Rays (RAY-files) when you have made an LT-command file (LTR-file) containing the names of the required (and existing) wave scenarios (SCO-files), Cross-Shore files (PRO files) and coefficients for Sediment Transport (CFS-files) and Energy Decay (CFE-files). Notice that multiple sets of the above files can be stored in a LTR-file, each set of input files will result in a RAY-file. All these input files can be made in Input Screens of this User Interface. These are free-format ASCII files. Hence they can also be made in other ways, for example with the help of an ASCII Editor. When you have computed one or more Transport Rays, then you can inspect them visually using the option Show Ray. The interactive LT-run offers the option inspect the results in greater detail. Information on wave propagation, current distribution and longshore transport distribution can be inspected visually for each condition in the interactive mode. The RAY-file only contains the summarised and schematised data that are necessary for describing the transport function along the coast for a CL-model.

CL-run

Independent of having RAY-files you can make a Basic Model file (MDA-file), which defines a curved coastline and the computational grid. By activating Show Model you can at all times check the coastline and grid points while building the model. To be able to proceed further you must first define the Global Transport file (GKL-file), which is valid along the entire coast. A Global Transport is defined by placing one or more RAY-files along the coast. Via inter- and extrapolation the program produces a defined transport function for every grid point. When you combine in Show Model the Basic Model with a Global Transport, it is possible to inspect the transport characteristics in all grid points both in a table and a diagram. A valid CL-model (a Case) requires boundary conditions that have to be prescribed at both boundaries of the modelled coastline. Finally, a layout-file (LAT-file) has to be created which defines the graphical representation of the coastline model. Show Model offers the possibility to create a default version of the LAT-file. The LAT-file is created via the button Define Case. After the default LAT-file has been created, it can be inspected visually via the button Show. You can impose the necessary details using the Edit option. This is easier than building the file from scratch. Furthermore, Groynes, Offshore breakwaters, Internal boundaries, Revetments, and Sources/Sinks can be defined. These are optional and are not necessary for a valid coastline model. The Case must be described in the CL command file, <case>.CLR. Just as is the case with an LAT-file, you will have the opportunity to create, under Show Model, a default CLR-file. All activated entities are placed into that CLR-file. With the Edit option of the CLR-file you can then arrange details such as time-step and number of steps.



When you apply Groynes, Offshore breakwaters, Internal boundaries, Revetments, and Sources & Sinks, then you can check their placements graphically in Show Model. When you are using Local Transports (with Groynes and Offshore breakwaters), you can also inspect their effects in Show Model. When the CLR-file is completed you can execute a CL-run. A CL-simulation can temporarily be interrupted for a graphical inspection of the transports as well as for the setting of additional output. After a CL-run a PRN-file becomes available. On this file you can run the interactive program Volumes to make integrations.

4.3 LT Input and Output

Under the LT (Longshore Transports) option of the main menu you can create or modify the LT input and inspect the LT output.

Figure 4.8

4.3.1 LT input:

The following files make up a valid LT-run (of which the LTR-file is the main input file): • a SCO-file (Wave and Current scenario), • a PRO-file (Bottom profile), • a SCE-file (Coefficients for Wave Energy Decay model), • a CFS-file (Coefficients for applied sediment transport formula), • and the coastal angle upon which the cross-shore profile stands perpendicularly. Based on the files listed above an LT-run will result in one Transport Ray stored in a RAY-file. An LTR-file contains the instruction for the calculation of one or several Transport Rays. In the following sub-section the editing/creating of the files mentioned above is described (the submenus for creating and editing are similar).



Wave and current scenario

If you select this option from the editing menu, first a window will pop up from which you can select the name of an existing scenario. After selection of the name or, if entering from the creation menu directly, you will get the input screen for editing the contents of a SCO-file:

Figure 4.9

For background information about the Wave/Current scenario, see Section 2.6.1. Additional information: • The number of combinations Wave/Current is limited to a maximum. For current settings

consult APPENDIX C • The scenario duration field counts automatically the actual number of days in the

scenario. • The total of percentages in the tide information must be 100%. • The total transport rate is defined as: Qs [m3/day] = {ΣQs [m3/day] × Duration [day] × Perc} / N [day] where N is the Normalisation base [day], and Σ is the summation of all combinations of

Waves and Current (Tide). If the transports that are based on the active wave-current scenario are representative for a long-term simulation it is important to set the normalisation base to one year (365 days). In this way the model interprets the transports as a yearly averaged net transports. If the scenario duration is shorter then 1 year it is then assumed that for the rest of the year no transports occur (for example during very calm periods or seaward directed wave conditions).



If you want to study the coastline development within one year, you can define scenarios for the different seasons in a year. In that case you must define the actual scenario duration as Normalisation base. In the CL-module you can use the different transport properties in the distinct phases of a Run (see also Section 2.12 and Section 4.5.2 ). Buttons: Ok The Scenario, of which the name is mentioned at the top of the screen, is saved and

you will return to the main menu. If a new scenario is created, you will first get a screen in which you can define its new name.

Cancel All modifications are cancelled and you will return to the main menu. Copy This is a useful option for making a new Scenario by modifying an existing one. After

having made the modifications, select Copy. Now you will be able to define a new name. After that you will return to the input screen where you will see the new name in the top line. The Ok action will make the situation permanent.

Insert Row Insert a new row before the selected row. Delete Row Delete the selected row.

Cross-shore profile

If you select this option from the editing menu, you will first get a window in which you can select the name of an existing Cross-shore profile. After selection of the name or, if directly entering from the creation menu, you will get the input screen for editing the contents of a PRO-file. With the View option you can graphically check the results of all entered data. For background information about the Cross-shore Profile see Section .2.6.2.



Figure 4.10

Additional information: • As a cross-shore profile can be applied on various locations along the coast the

orientation has to be prescribed at the LT-run specification. In this way it is possible to apply a cross-section at different locations (under different coastline orientations).

• You can use your own positive x-co-ordinate direction: Landward or Seaward. • You can define the profile in terms of Depth with respect to an absolute Reference level,

or in terms of relative Bottom levels with respect to an absolute Reference level. • For the LT-calculation a non-equidistant numerical grid is defined on the Cross-Shore

Profile. You must define the step size dx for that grid in the first table. The actual dx at a position x is determined by linear interpolation in the table. Outside the table domain the border values are used.

• The number of rows in the dx table is limited to a maximum. For current settings see APPENDIX C

• The number of points (rows) in the Profile is limited to a maximum. For current settings see APPENDIX C

• The resulting number of grid points is limited to to a maximum. For current settings see APPENDIX C



Wave parameters

If you select this option from the editing menu, you will first get a window in which you can select the name of an existing set of Wave parameters. After selection of the name, or in the case of directly entering from the creation menu, you will get the input screen for editing the contents of a CFE-file. The user is referred to the Technical Reference Manual WL|DELFT

HYDRAULICS (1992) (Chapter 6) for more information on the coefficients.

Figure 4.11

There is always a default set of Wave parameters DEFAULT.CFE available.

Transport parameters

If you select this option from the editing menu you will first get a window in which you can select the name of an existing set of Transport parameters. There are four types of transport formulae and each type requires a specific set of parameters. The program recognizes from the contents of the CFS-file which of the four types it is dealing with. The available transport formulas are: • Bijker for sand • Van Rijn for sand • CERC for sand • Van der Meer/Pilarczyk for gravel For each type a file with the default set of transport parameters is available: • DEF_BIJ.CFS • DEF_RIJ.CFS • DEF_CER.CFS • DEF_GRA.CFS After selection of a name (or entering a name in the creation menu), you will get the input screen for editing the contents of the appropriate CFS-file. For more information about the transport formulae see Chapter 6, theoretical reference document.



Figure 4.12, Parameters for the Bijker transport formula

Additional information: • The coefficient b in the Bijker formula may vary between a value of about 5 for shallow

water and a value of about 1 for deep water. You can define both values and the position in the Cross-Shore profile (by means of the criteria Hsig/h) where the deep water and shallow water begins. Between those two positions the program will interpolate.

Figure 4.13



Figure 4.14, Parameters for the Van Rijn transport formula

Figure 4.15, Parameters for the CERC transport formula



Figure 4.16, Parameters for Van der Meer/Pilarczyk

Run Specifications

If you select this option from the Edit menu you will first get a window where you can select the name of an existing set of Run Specifications. After selection of the name, or if directly entering from the creation menu, you will get the input screen for editing of the contents of a LTR-file.

Figure 4.17

Each row in the input screen of the Run Specifications will result in a Transport Ray, the RAY-file. You must enter: 1. the orientation of the Coast,



2. the active profile height, 3. the names of the four input files:

• the PRO-file (Cross-Shore PROfile), • the CFS-file (CoeFficients TranSport), • the CFE-file (CoeFficients Energy decay), • the SCO-file (Wave SCenariO),

4. and the name of the output file: • the RAY-file.

You will find an output report of the LT-Run (defined in <name>.LTR) in the GLO-files, which have the same names as the RAY-files. The names of the input files must be names of existing files. The program has the following input feature for entering the names: • Move the mouse pointer onto a field (i.e. for the SCO-file) and click. • A list of all available SCO-files will appear in the File Name window. • Click on the name of the desired file. • While keeping the left mouse-button pressed, move to the input field and release the

mouse button. You will see that it is impossible to drop the file in a wrong field. Further documentation: • Section 2.5 about the Transport Ray. • Section 2.6 about the LT-Run • Section 4.5.4 about the .GLO-report file

4.3.2 LT Runs and Output

There are two ways to execute LT-runs: 1. Via the Run option in the main menu. The transports at every ray in the .LTR command

file will be executed. 2 Via LT’s submenu: LT/Run Interactive. Per ray a command to make a calculation can be

given. The option Show Rays in LT’s Main Menu offers the option to graphically inspect a RAY-file.

Show Rays

When you select this function you will get a window with all available RAY-files to choose from.



Figure 4.18

When you select a RAY-file you get: • The computed transports (Qs) as a function of the relative coastal angle: the approximation Qs = c1 θR exp[−(c2 θR)2] Mm3/y, where θR = the coast-angle − the equilibrium angle • A graph plotted in the real world co-ordinates, with the coast normal and the

schematised Transport data along it, the so-called By-Pass function. The By-Pass function is defined by the points along the coast normal where 0%, 2%, 20%, 50%, 80%, 100% of the transport passes, and the total transport at the current coastal angle. The function is required to calculate the transport passing along a groyne. Between the points the program interpolates linearly, meaning that the transport function itself is a block function. The angles presented in the Qs - θ curve are relative to the coastline used in the computation (so relative to 335 deg in the example presented below).



Figure 4.19

Figure 4.20

LT/Run Interactive

After the selection of this option you will see a window at the screen where you can select an LTR-file and at the right of it a window to select the Transport Ray to operate on.

Figure 4.21

After a RAY-selection you will see that the calculation mode is set at ‘estimate’. If you press the Calculate button the program will calculate the equilibrium angle, and the coast-rotation due to the Tidal Current using a simple calculation method. (see also Section 2.4).



The dotted line concerns the situation without Tidal Current, the solid line the situation with Tidal Current.

Figure 4.22

Figure 4.23

Now the options Transport and Series Transport are enabled. If you select Transport you will be able to select a Coastal Angle with the mouse, or by data entry in the Angle-field at the left. After pressing Calculate a calculation of the transport will be made and the result will be plotted and displayed numerically in the Qs-field. The option View is now enabled.

Figure 4.24



Figure 4.25

The option Series Transports gives the same result as in an LT-batch step. At the equilibrium angle and at five angles left and right of it, the transport is calculated. The correct equilibrium angle and the coefficients c1 and c2 are calculated and displayed. If the on/off button Write .Ray is on, the RAY-file will be written.

Figure 4.26

Figure 4.27

The View option



After the calculation for a single Coast Angle rotation you can select view and inspect the results in more detail. The screen you will see is composed of a window with radio buttons to select functions, two numerical windows to display results and two graphical windows, one for the selected function, the other for the Cross-Shore Profile.

Figure 4.28

Figure 4.29

Figure 4.30

Figure 4.31

In the bottom window at the left, the used Coastal Angle rotation, the Qs-total and the applied normalisation factor (see Section 4.3.1) will be displayed.



In the first numerical display window you can scroll through the individual wave-data and -results. The contribution to the longshore transport Qs for the selected wave is displayed and the summation of Qs up to this wave. You should realise that the summation at the last wave will not be equal to the Qs-total if the normalisation factor is not equal to unity. Qs-total is the yearly averaged transport that will be used in a CL-calculation.

ZoomIn/ZoomOut

Under View of the main menu a ZoomIn/ZoomOut option is available.

Figure 4.32

Steps for ZoomOut:

Figure 4.33

• Select the View option from the top line menu. • Select ZoomIn. • Move the mouse pointer to the top left corner of the

desired box. • Press the left mouse button and keep it pressed while

moving to the bottom right corner of the desired box and release the button.



Figure 4.34

Steps for ZoomOut:

• Select the View option from the top line menu. • Select ZoomOut. The area containing the whole model is now replotted.

4.4 CL input

Under the CL (CoastLine) option of the main menu, you can create or modify the input for a CL-Run.

Figure 4.35

.MDA .RAY .GKL .BCO .GRO .OBW .REV .SOS .BCI .LAT .CLR

A CL-Run should be specified under the option Run Specifications. The Run Specifications reside in the CLR-file. Information about the Screen Layout residing in the LAT-file is also required. The base name of the LAT-file and the CLR-file are the same. In the CLR-file references to the model entities (files) are made. Required model entities are: • the Basic Model (MDA-file), • the Global Transport, (GKL-file), • Boundary conditions (BCO-file).



The other model entities are optional. The option Show Model offers visualisation facilities and also the option to let the program create a default CLR-file and LAT-file based on the Basic model and Global Transports.

4.4.1 The Basic Model

The data defining the basic model reside in the file <Model>.MDA. The base name of the file equals the Model-name, meaning that there is only one MDA-file in a Model directory. When you select the option Basic Model, the next window will pop up:

Figure 4.36

Further Documentation: • Section 2.4 The Basic Model Additional information: • The number of Basic Points is limited to a certain maximum. For current settings see

APPENDIX C • The total number of x-grid points is limited to a maximum. For current settings see

APPENDIX C • The number of points in the last column defines the number of grid points between the

current Basic Point and the previous Basic point. So this number has no meaning for the first Basic point; you should set it to zero for the sake of clarity.

• To define a discontinuity at a Basic Point, you must define two y-points at one Basic Point. For interpolation of y at xy-points, Y1 is used at the left side and Y2 at the right side. Discontinuities may be necessary where groynes or internal boundaries are active in the initial situation. Normally only Y1 is defined.

Inspect the Basic Model



Figure 4.37

Once having defined your Basic Model (the contents of the MDA-file), it is possible to inspect the schematisation made by the program, using the option Show Model. When you do so, you will get a window in which you can define all required and optional Model parameters to add to your Basic Model. You should start with adding the Global Transport, the GKL-file (see next section). After that, all other features are available. If you add none of them, then only the Basic Model itself will be shown if you press the Show button. Zooming in on a model detail can be done by using the View option of the menu at the top of the screen.

4.4.2 Global Transport

The next step in making an executable Model, is the definition of the Global Transport, which is defined by positioning of one or several Transport Rays along the model. When you select the Global Transport option the following input screen will pop up.

Figure 4.38



Documentation: • Section 2.5 Transport Rays • Section 2.7 Global and Local Transports Additional information: • The position in x-direction is given as a reference point in world co-ordinates (Xw,Yw).

As in the program a Transport Ray must be located at an x-grid point (points where Qs has been defined); the program will subsequently map the position to the nearest x-grid point.

• The names of the RAY-files should be names of existing files. The program offers the following input feature for entering these names: • Activate a field. A list of all available RAY-files will appear in the File Name

window. • Click on the required file. • While keeping the left mouse-button pressed, move to the input field and then

release the mouse button. You will see that it is impossible to drop the file in a wrong field.

Show Basic Model + Global Transport

You can now inspect the schematisation of the Global Transport resulting in transport properties in each Qs-point. Steps: • Select Show Model. • Activate the Global Transport field. A list of all Global Transport files is displayed in the

file window. • Drag the desired filename from the list and drop it in the Global Transport-field. • Press the button Show



Figure 4.39

In the next example a detail of the model is plotted.



Figure 4.40

You will see the following information in the plot: • In bold lines for the inserted Transport Rays and in normal lines for the interpolated

Transport Rays at the Qs-points: an arrow located at the beginning of the dynamic area in the averaged wave direction (perpendicular to the equilibrium angle) and an arrow indicating the transport capacity in the ray. Both the wave arrow and the transport arrow are scaled with respect to the transport capacity at the current coastal angle.

• In the top left corner: a list with erosion (+) / sedimentation (-) values at each y-point along the model. You can move along the y-points of the model with a cursor.

• In the top right corner a graph of the transport capacity at the current (initial) coastal angles is shown. The cursor location is also indicated in this graph. The transport capacity at the two neighbouring Qs-points is displayed at the top of the graph.

4.4.3 Boundary Conditions

The third and last mandatory step in making an executable CL-Model, is the definition of the Boundary Conditions at the left and right Model border. When you select the option Boundary Conditions from the editing menu, an input screen will pop up. After selection of the name of a BCO-file (or when you activate Boundary Conditions in the Creation menu),



you will get the input screen where you can define the boundary condition for both sides of the model.

Figure 4.41

Preceding documentation: • Section 2.8, ‘Boundary conditions’ In the first input box you must select the model side which you want to concentrate on, clicking a radio button. In the second input box you must make a choice of one of the four options. For the third option, Qs constant, you must enter the value of Qs in an input field (see the printed screen above). If you are choosing option four, Qs f(t), you must select the name of an available TABxxx.TAB-file and the column number of the tabulated function of time (see screen below). Where xxx represents a number of three figures: 001, 023, etc.



Figure 4.42

Description TAB---.TAB file

The TAB---.TAB-file is a free format ASCII-file with tabulated Qs(t) functions. The functions can be applied for Boundary conditions and for Sources and Sinks. The basic column (column 0) concerns the points of time in years. It is a non-equidistant series. The other columns (1,2...,K) contain Qs values. By defining a period P in years, you will make the series periodical. Contents of the file: record 1: K integer (number of columns) record 2: P real (period in years) record 3: TIME COL_1 COL_2 .... COL_K (comment) record 3+1: t_1 Qs Qs Qs record 3+2: t_2 Qs Qs Qs record 3+N: t_N Qs Qs Qs

Qs in m3/y Interpolation rules: Suppose t is the current time (in years). • If P not equal 0.0 then the function is periodical with a period of P years. If in that case t

is greater than t_N, t will be decreased with P until t is less than or equal to t_N. • If t is less than t_1, Qs_1 will be applied. • If t is greater than t_N (if non periodically), Qs_N is applied.



• If t lies between t_1 and t_N, then Qs is found by linear interpolation.

Show Basic Model + Global Transport + Boundary Conditions

You can now inspect the schematisation of the Global Transport resulting in transport properties in each Qs-point together with the Qs-values at the boundaries. Steps: • Select Show Model. • Click on the Global Transport-field. A list of all Global Transport-files is displayed in

the file window. • Drag the required file from the list and drop it in the Global Transport-field. • Select the Boundary Condition-field. A list of all Boundary Condition-files is displayed

in the file window. • Drag the required file from the list and drop it in the Global Transport-field. • Click the button Show.

4.4.4 Case definition

The finally required step to make an Executable Model (MDA + GKL + BCO) is the definition of a case, consisting of: • The definition of the Run Specifications resulting in the file: <case>.CLR; • Making of a Screen Layout resulting in the file: <case>.LAT. Both actions are options in the CL-menu. You can select the options Run Specification and Screen Layout from the Create Input menu and enter the data from scratch.



It may, however, be convenient to have a default version of those files to edit. You can get those default versions of LAT- and CLR-files based on an Executable Model (and some optional parameters). If you enter the Show Model option and select the GKL-file, you will see that the option Define Case is activated. When you select this option, you will be asked to input the case name and both files are created. If a file already exists no overwrite will occur.

Figure 4.43

You will see in the CLR-file that for optional parameters, which have not been set by the user, will result in filenames NULL.GRO, NULL.OBW, etc. Those files are existing default files, meaning that there are no groynes, no offshore breakwaters etc. If you do not select a BCO-file, the default file FIXED.BCO is applied. FIXED.BCO is also an existing default file, meaning that the y-position at both sides is constant. For more information see the next paragraph, Run Specification. In the default LAT-file an example of all possible items is applied: • A simple Land Polygon to define the land area. • A polygon (a square). • A text (the case name) inside the polygon. • City marks at both model boundaries. For more information see next sub-section, Screen Layout. Run specifications If you select this option in the editing menu, you will first get a window in which you can select the name of an existing set of Run Specifications. After selection of the name, you open an input screen for editing of the contents of a CLR-file. (Coast Line Run):



Figure 4.44

Preceding documentation • Section 2.11, Phase Model; • Section 2.12, The CL-Run Specifications; • Section 3.3 Postprocessing utilities. Additional information • In the upper left box you must define the time unit (Year, Month, Week, Day, or Hour).

The time unit is the unit in which you specify the time points of the whole time domain of the run. Furthermore, you must enter the Start time, the number of numerical time-steps dt into which the time unit is divided, and the Number of Cycles, that is, the number of times the set Run Phases should be repeated.

• In the next box, which is a spreadsheet input box, you must define one line of information for each Phase of the Run. The first two fields define the time domain of the Phase. If for example the time unit is ‘Year’, then from Year 2 to Year 5 means that the Phase starts at the beginning of year 2 and continues up to the beginning of year 5. The Phase time is relative with respect to t0. So the current time t in the time process is t0 + Phase time. You should be aware of that, because the current time t is used for the interpretation of Qs (t) functions.

• In the other seven fields you must enter the names of the model units defining the Phase Model.

The required units: • the GKL-file (Global transports) • the BCO-file (Boundary COnditions)



The optional entities: • the GRO-file (GROynes) • the SOS-file (SOurces and Sinks) • the REV-file (REVetments) • the OBW-file (Offshore BreakWaters) • the BCI-file (Boundary Conditions Internal) The names of the input files should be names of existing files. The program offers the following input feature for entering the names: • Click on a field (for example, for the BCO-file). • A list of all available BCO-files will appear in the File Name window. • Click on the file you want. • While keeping the left mouse-button pressed, move to the input field and then release

the mouse button. • You will see that it is impossible to drop the file in a wrong field. In the input box at the bottom of the screen you should enter the time points, in terms of numerical steps dt, for which information should be written to the PRN-file. If, for instance, the input reads: First time step: 10, Step Period: 3, Number of steps: 4 then output is produced at t0 (default), t0+10.dt, t0+13.dt, t0+16dt and t0+19dt. Output at additional time points can be made at any moment during the calculation. You can interrupt the process and make a request for output at that moment.

Screen Layout

If you select this option from the editing menu, you will first get a window in which you can select the name of an existing Layout-file. After selection of a name (or when you enter a name in the creation menu), you will get the input screen for editing the contents of a LAT-file.



Figure 4.45

Preceding documentation: • Chapter 2.10, The Screen Layout Additional information: • In the first input box the default scale of the model area in the screen is defined by

means of the x-domain and the value of the bottom y-level. The top y-level is implicitly determined by the size of the window and by the rule of orthogonality.

• In tab “Color Model” you can define the colour for the Land and Sea area. The available colours are listed in a colour bar at the left side of the screen. By focusing on the number behind Sea or Land and subsequently clicking on a colour in the colour bar, the preferred colour is defined.

• In tab “Text” you can define texts at any place in the model area, and in the fourth box you can define texts combined with a circle filled with colour. The latter feature can be used to mark the location of cities, villages, etc. Text and fill colours are selectable in the same way as Land and Sea colours.

• In tab “Circular marks with text” you can define circles in combination with text string. • In tab “Land polygon” you can define the land polygon, which describes the connection

between the end and the beginning of the coastline (see also Section 2.8), in order to define a closed land area. The Land Polygon is required, other polygons are optional.

• In tab “Polygon(s)” you can define all kinds of polygons. These polygons are optional.



Figure 4.46

Figure 4.47

If the last and the first point of a polygon are equal, it is a closed polygon and it can be filled with a colour. For the line colour (also fill colour) you can select RGB values yourself.

Show Layout + Basic Model + Global Transport

Now you can inspect the Layout in combination with the schematisation of the Global Transport. Steps:



• Select Show Model. • Focus on the Global Transport field. A list of all Global Transport files is displayed in

the file window. • Drag the wanted file name from the list and drop it in the Global Transport-field. The

field for selecting the Layout file will be activated now. • Click on the Layout field. A list of all Layout files is displayed in the file window. • Drag the preferred file name from the list and drop it in the Layout field. • Click the button Show. In the next example a detail of the model is plotted.

Figure 4.48

4.4.5 Optional Model Entities

4.4.5.1 Groynes

If you select this option from the editing menu, you will first get a window where you can select the name of an existing GRO-file. After selection of the name (or when you enter the name from the creation menu), you will get the input screen for editing the contents of a GRO-file.



Figure 4.49

In a GRO-file you can define a set of groynes. All groynes for one case should be defined in a single GRO-file. Groyne selection buttons: With the three lowest buttons at the right side of the screen, you can select the individual groynes in the set of groynes in order to specify the data. New Define a new groyne. Delete Delete the current groyne. [2 of 5] You can read here the number of the current groyne and the total number of groynes

in the set. For instance, [2 of 5] means there are five groynes and you have activated groyne 2. You can activate the preferred one by using the Up/Down button at the right side of the display box.

Preceding documentation: • Section 2.9.1 Groynes Additional information: • In the top of the screen you must define the Reference Point, the Blocking Percentage

and the Y-position at the top of the groyne. The meaning of these parameters is described in Section 2.9.1.

• If there are no Local Transport Rays related to this groyne, you can carry on with another groyne or quit the screen.



Local Transport Rays If there are Local Transport Rays, you can choose from five situations defining the impact area of the Transport Rays. • The area between the previous groyne and the current groyne, and the area at the right

side of the current groyne. • The area at the right side of the current groyne. • The area at the left side of the current groyne. • The area at the right side of the current groyne and the area at the left side of the current

groyne. • The area between the previous groyne and the current groyne. Select one of the five situations by clicking on a radio button. The five situations are explained symbolically next to the buttons. Depending on the situation you should define now one or two sets of Local Transports Rays. The definition of a set of Local Transport Rays should be done in the same way as for the set of Global Transport Rays. The position in x-direction is given as a reference point in world co-ordinates (Xw,Yw). Because in the program a Transport Ray must be located at a x-grid point (points where Qs is defined), the program will map the position to the nearest x-grid point. The names of the RAY-files should be names of existing files. The program offers the following input feature for entering the names: • Focus on a field. • A list of all available RAY-files will appear in the File Name window. • Click on the desired file. • While keeping the left mouse button pressed, move to the input field and release the

mouse button. You will see that it is impossible to drop the file in a wrong field. The impact area is bounded by a groyne or by the last inner Qs-point covered by the set of Transport Rays. The interpolation rules are described in Section 2.9.1.

Show Groynes with Local and Global Transport

Now you can inspect the real positions of the groynes and the impact of the Local Transports and Global Transports. Steps: • Select Show Model. • Select the Global Transport-field. A list of all Global Transport-files is displayed in the

file window. • Drag the wanted file name from the list and drop it in the Global Transport-field. • Click on the Groyne-field. A list of all Groyne-files is displayed in the file window. • Drag the wanted file name from the list and drop it in the Groyne-field. • Click on the button Show. In the next example a detail of the model is plotted.



Figure 4.50

4.4.5.2 Offshore Breakwaters

If you select this option from the editing menu, you will first get a window where you can select the name of an existing OBW-file. After selection of an existing name or entering a new name, you will get the input screen for editing of the contents of an OBW-file.



Figure 4.51

In an OBW-file you can define a set of Offshore Breakwaters. All Offshore Breakwaters for one case should be defined in one OBW-file. Preceding documentation: • Section 2.9.2, Offshore Breakwaters Additional information: • At the top of the screen you must define the Xw,Yw-position of the left and right side of

the breakwater. As mentioned before (Section 2.9.2), the breakwater itself has no influence on the results. The influence of the breakwater on the transports along the coast can be modelled by the application of Local Transport Rays. The local transport rays should be computed with LT on the basis of the modified local wave climates around the breakwater. The local wave climates should be determined with a suitable wave propagation model. The extended version of Unibest (see Section 5.1) offers the option to link results of sophisticated wave modelling with the Delft3D model to Unibest. If there are no Local Transport Rays related to this Offshore Breakwater, you have finished now and you can either continue with another Offshore Breakwater or quit the screen.

Local Transport Rays



If you want to insert Local Transport Rays in the area around the breakwater, you must click the radio button 'yes'. The definition of a set of Local Transport Rays should be done in the same way as for the set of Global Transport Rays. The position in x-direction is given as a reference point in world co-ordinates (Xw,Yw). Because in the program a Transport Ray must be located at an x-grid point (points where Qs is defined), the program will map the position to the nearest x-grid point. The names of the Ray-files should be names of existing files. The program offers the following input feature for inputting the names: • Focus on a field. • A list of all available .RAY-files will appear in the File Name window. • Click on the desired file. • While keeping the left mouse button pressed, move to the input field and release the

mouse button. You will see that it is impossible to drop the file in a wrong field. The impact area is bounded by the last inner Qs-points covered by the set Transport Rays. The interpolation rules are described in Section 2.9.2

Show Offshore Breakwaters with Local and Global Transports

Now you can inspect the impact of the Local Transports related to Offshore Breakwaters together with the Global Transports . Steps: • Select Show Model. • Select the Global Transport-field. A list of all Global Transport-files is displayed in the

file window. • Drag the desired file from the list and drop it in the Global Transport-field. • Select the Offshore Breakwater-field. A list of all OBW-files is displayed in the file

window. • Drag the desired file from the list and drop it in the Offshore Breakwater-field. • Press the button Show. In the next example a detail of the model is plotted.



Figure 4.52

4.4.5.3 Revetments

If you select this option from the editing menu, you will first get a window in which you can select the name of an existing REV-file. After selecting an existing name or entering a new name, you will get the input screen for editing of the contents of a REV-file. In a REV-file you can define a set Revetment sections. All Revetment sections for one case should be defined in one REV-file. At the top of the screen you must define the positioning type: relative to Y(t=0) (implying that the revetment is defined relative to the initial coastline) or absolute to the Reference Point, see Section 2.9.3. In the input table at the bottom of the screen you must input the Xw,Yw-position of the Reference Points and the Y-values defining the top position of the Revetment section.



In this example two Revetment sections are defined. The first has been made Absolute and the second has been made Relative.

Figure 4.53

Figure 4.54

Preceding documentation: • Section 2.9.3 Revetments



Show Revetment sections and Global Transport

Now you can inspect the exact position of the Revetment sections at Y-points and the impact of the Revetments, applied at the initial Y(t=0) coastline, on the Global Transports. Steps: • Select Show Model. • Select the Global Transport-field. A list of all Global Transport-files is displayed in the

file window. • Drag the desired file from the list and drop it in the Global Transport-field. • Follow the same procedure for the REV-file and the LAT-file. • Press the button Show. In the next plot a detail of the absolute positioned revetment section is shown.

Figure 4.55

In this plot a detail of the relative positioned section is shown.



Figure 4.56

4.4.5.4 Sources and Sinks

If you select the option Sources and Sinks from the editing menu, you will first get a window in which you can select the name of an existing SOS-file. After selecting an existing name or entering a new name, you will get the input screen for editing of the contents of a SOS-file. In a SOS-file you can define a number of Sources/Sinks. All Sources/Sinks for one case should be defined in a single SOS-file. At the top of the screen you must define the Xw,Yw-position of the Reference Point defining the Source/Sink. For an explanation see Section 2.9.4. It is possible to specify constant and time dependent sources and sinks. The latter can be used for instance to simulate the behaviour of rivers etc. For that purpose you offer tabulated time series residing in a .TAB-file. Reference is made to Section 4.4.3 (Boundary conditions and description of the TAB-file).



Figure 4.57

Figure 4.58

Preceding documentation: • Section 2.9.4, Sources and Sinks. • Section 4.4.3, Boundary conditions • Section 4.4.3, Description of the .TAB-file.

Show Sources and Sinks and Global Transport

Now you can inspect the exact position of the Sources/Sinks at Y-points and their impact on the initial erosion/sedimentation. Steps:



• Select Show Model. • Activate the Global Transport-field (a list of all Global Transport-files is displayed in

the file window). • Drag the desired file from the list and drop it in the Global Transport-field. • Follow the same procedure for the SOS-file. • Click the button Show. In the next plot a detail of the area is shown where a Sink of −500 [k(m3/y)] and a Source of 500 [k(m3/y)] are located (indicated by round dots). The graph of transport rates Qs(x) shows initial transport capacities at the initial coastal angles. So the graph does not show a decrease of transport between the Sink and Source in the initial situation. During the LT run the sources and sinks will affect the transport, due to a coastline rotation caused by erosion at the Sink and sedimentation at the Source. The table in the upper left corner shows the initial erosion and sedimentation at the Y-points of the Sink and Source.

Figure 4.59

4.4.5.5 Internal Boundaries

If you select Internal Boundaries from the editing menu you will first get a window where you can select the name of an existing BCI-file. After selection of an existing name or entering a new name, you will get the input screen for editing the contents of a BCI-file.



Figure 4.60

In a BCI-file you can define a set of Internal Boundaries. All Internal Boundaries for one case should be defined in a single BCI-file. Preceding documentation: • Section 2.9.1, Groynes; • Section 2.9.5, Internal Boundaries. Additional information: • The effect of the Internal Boundary is the same as for Groynes but with the exception

that internal boundaries have no Local Transport Rays. At the top of the screen you must define the Reference Point, the Blocking Percentage and the Y-position of the top of the Internal Boundaries. The effect is the same as for Groynes. Internal Boundaries can be used at locations with a discontinuous behaviour of the coastal development, where the local transport is not determined by the local coastal angle. The Internal Boundary offers a limited facility to simulate the behaviour of those points. You must define the length of the ‘groyne’ long enough to block the whole transport area. Both sides of the Internal Boundary are then separated and the coast angle at the Internal Boundary has no influence on the transport. The transport is determined by the coast orientation at the updrift side of the Internal Boundary. The Blocking Percentage can be used to reduce the amount of passing transport if necessary.

Show Internal Boundaries with Global Transport

Now you can inspect the real positions of the Internal Boundaries and the impact of the blocking properties on the transports. Steps: • Select Show Model. • Focus on the Global Transport-field. A list of all Global Transport-files is displayed in

the file window. • Drag the desired file from the list and drop it in the Global Transport-field.



• Follow the same procedure for the BCI-file. • Press the button Show.

4.5 The Run Option

When you select Run from the Main menu the following submenu will pop up:

Figure 4.61

You can make: • Reports, • LT Runs based on instructions in LTR-files, • CL Runs of cases prepared in CLR-files, • Volume Runs based on CL result files (PRN-files). You can inspect the following Report files: • GLO-files, reports from Transport Ray calculations in LT Runs. • PRN-files, results from CL-Runs. • DES-files, description of the connection of all files related to a CL case. A DES-file is

optional output (see Options) from a CL-Run. • GIS-files, optional output (see Options) from a CL-Run. It can be used for export of

coastlines to GIS systems. • VOL-files, output files from Volume calculations.

4.5.1 Running the LT-module

When you select LT-Run from the Run menu, all available LTR-files are listed in a file window. You will start an LT-Run by selecting an LTR-file from the list and pressing the Ok button. During the calculation, the pop-up message LT calculation is displayed. In the bottom line of the screen you can see the rotation number and name of the Transport Ray being processed and the total number of the Transport Rays. After the LT-Run the following results can be inspected: • GLO-files under Reports in the Run-menu • RAY-files, graphically, under LT / Show Transport Rays • RAY-files, numerically, under CL / Edit Input / Transport Rays.



4.5.2 Running the CL-Module

When you select CL-Run from the Run menu all available CLR-files (cases) are listed in a file window. You will start a CL-Run by selecting a CLR-file from the list and clicking the Ok button. The calculation screen of CL will now appear. At the left side it contains a display window with five action buttons and at the right side a graphical window with the model in it.

Figure 4.62

In the first information line you can see which is the current cycle and phase. In the second line the current time and the time domain is displayed. The third line shows the Status: Wait or Run. Buttons: Start The option is activated in the Wait Status.

The program will start or continue the calculation. The Status will become Run. The information at lines one and two is updated at each time-step. In the graph the

coastline is refreshed at each time step. In the Run status only the Wait option is activated.

Wait The option is enabled in the Run Status.



The process is interrupted. The Status will become Wait now. In the Wait Status the options Start, End, Show, and Output are activated.

At the end of the calculation the status will automatically become Wait.

End The option is activated in the Wait Status. The CL-Run will be terminated (if not finished already), and you will quit the CL-Run

task. Show The option is activated in the Wait Status.

The graphical and numerical information about the transport properties in each grid point are shown.

Output The option is activated in the Wait Status. The result of the current time point is added to the regular results in the PRN-file. The

time points of the regular results are defined in the CLR-file. After the CL-Run the following results can be inspected: • The PRN-file under Reports in the Run-menu; • The DES-file under Reports in the Run-menu (file is Optional, see Section 4.6); • The GIS-file under Reports in the Run-menu (file is Optional, see Section 4.6).

4.5.3 Run Volumes

When you select Volumes-Run from the Run menu all available <case>.PRN-files are listed in a file window. You start a Volume execution by selecting a PRN-file from the list and clicking the Ok button. Now the calculation screen of Volumes will appear.

Figure 4.63



In the two input boxes at the top of the screen you can define the x-domain and the t-domain for the volume integration calculation. You cannot input the data yourself, but you must select them from the lists of Qs-point locations and time-point locations.

Figure 4.64

The volume calculation is illustrated in Figure 4.1, where:

B(1,1) = the volume passed at point x1 up to time t1 B(1,2) = the volume passed at point x1 up to time t2 B(2,1) = the volume passed at point x2 up to time t1 B(2,2) = the volume passed at point x2 up to time t2 S1 = the net volume of sources – sinks between x1 and x2 up to time 1 S2 = the net volume of sources – sinks between x1 and x2 up to time 2

Buttons: Ok You will return to the main menu. Cancel All actions will be deleted and you will return to the main menu. Compute A volume calculation will be executed based on the defined x-domain and t-

domain. Save You will get a file definition screen now, in which you can define the base name

of a VOL-file on which the results will be saved. You can inspect and print the VOL-file under Reports in the Run-menu.

4.5.4 Inspect Run Reports

When you select Reports from the Run menu the following input screen will pop up:



You can inspect the following Report files: • GLO-files, reports from Transport Ray calculations in LT-Runs. • PRN-files, results from CL-Runs. • DES-files, description of the connection of all files related to a CL-case.

A DES-file is optional output (see Options) from a CL-Run. • GIS-files, optional output (see Options) from a CL-Run. It can be used for the export

of coastlines to GIS systems. • VOL-files, output files from Volume calculations. In the input box at the screen bottom you can select the desired file extension. In the file window a list of all available files with that extension will appear. When you select a file the UB program will bring you in the Window program Write and will copy the contents of the file to it. The option File from the Write menu offers you the possibility to print the file.



The GLO-file

Figure 4.65

Figure 4.66

The following information is written to the GLO-file: • name of the LT-Run; • names of input files (PRO, SCO, CFE, CFS); • name of the RAY-file; • Transport properties; • Characteristic transport values:

1. max. and min. transport and angle; 2. transport at coast angle zero (with respect to coast orientation); 3. list of transport properties for each wave in the domain ( –90, +90) with respect to

the coastal orientation of the Ray.

For more information see documentation: Section 2.4 and the explanation of the next two examples.



The PRN-file

Figure 4.67

The following information is written to the PRN-file: • name of the CL-Run. For each output step (For all x-cells): • y-position in world co-ordinates (xw,yw) (Figure 4.2); • y-position (along coastal normal) with respect to xy grid points; • y-position with respect to y(t0); • actual source or sink transport; • total source volume up to time t; • total stored volume in cell up to time t. For all model transport rays (coastal normal at x-grid points) • x-position along the curved x-axis; • coast angle (in the world co-ordinate system); • the actual transport;



• the volume passed up to t.

Figure 4.68, Numerical scheme

The DES-file



Figure 4.69

The DES-file summarises the CL-Case, and in particular all model elements (files) related to the case. RAY-files can be used for the Global Transports and for Local Transports at Groynes and Offshore Breakwaters, the relation of which is visualised. If the Transport Ray was the result of an LT-Run, the input files for the Transport Ray are mentioned too. If the Transport Ray was created or edited by hand (option CL/Edit Input /Transport Rays), they are of the type MANUAL and the origin cannot be traced anymore.

The GIS-file



Figure 4.70

At t=0 and at the end of each Phase, the co-ordinates [Xw,Yw] (m) of the coastline, as a coastline polygon, are written to the GIS-file. The first line of the file contains the name of the file: <case>.GIS. Preceding to each coastline polygon is a header line: PHASE, i, j, k, t is written with the meaning: i end of Phase i j end of time unit j k end of time-step k t at time t [year] The GIS-file is optional (see Options). The Model properties for each Phase can be derived from the information on the DES-file.

The VOL-file

The VOL-file is the result of a Save action during a session of the Volume calculation option.



Figure 4.71

The contents of the VOL-file are the same as the contents of the calculation screen of the Volume option described in Section 4.5.3.

4.6 Options

Figure 4.72

Under Options of the main menu you will find one category: Output. If you select Output you will get the following input screen:



Figure 4.73

By clicking on radio buttons you can write the output to a DES-file and/or a GIS-file.



Tools 5

5.1 Unibest CL+ & Delft3D-Wave

(OPTIONAL Unibest CL+ functionality) To use this option it is assumed that the user is familiar with Unibest CL+ and the software package Delft3D. A special version of morsyssm.exe (dated 9-10-00) is required. With this version, if a md-vwac file (see below) is present in the selected working directory in Delft3D, wave computations will be carried out for all wave conditions in the md-vwac file (instead of the wave condition in the md-wave file). In this way a large number of wave conditions can be computed in batch mode.

5.1.1 Interface

First Unibest has to be started and a Unibest model has to be selected via the Model manager. The first screen of Unibest the interface enables the user to select the option of 2D wave computations, by means of an additional button Tools|2D-Wave in the menu bar ( Figure 5.1).

Figure 5.1

If Tools|2D-Wave is not selected Unibest uses Endec for wave computations. This is the “normal” use of Unibest. If Tools|2D-Wave is selected the interface provides a second screen (Figure 5.2) with tabs “Delft3D Wave” and “Local Scenario Files” for the steps required to define and run a 2D wave model. The function of each tab will be descibed in the next sections.

5.1.2 DELFT3D-WAVE: Link between Unibest and Delft3D to define and run 2D wave model

After selection of tab “Delft3D Wave” the window shown by Figure 5.2 becomes visible.



Figure 5.2

The function of this tab is to prepare a Delft3D Wave computation for several wave conditions. Additional information: • Delft3D Wave Directory|Browse, by pressing this button the user can select the working

directory of Delft3D. . Furthermore the name of the Delft3D case (run-identification of Delft3D) should be given by the user.

• Offshore Scenario|Browse, by pressing this button the user can select the File the deep water .SCO file from Unibest is selected. The wave data in this file will be used as boundary conditions for the Delft3D-wave run.

• Start Delft3D-Wave, by pressing this button the Delft3D interface is activated. At the same time relevant wave data Hs, Tp, θ, h are read from the selected deep water .SCO (Offshore Scenario) file and transferred to the md-vwac.<case> file. The md-vwac file is placed in the selected working directory for Delft3D.

The format of the md-vwac file is presented below. The values of ms, U10 and theta-W are default values added by the program. They can be modified by editing the md-vwac file. Note that in the md-vwac file the default values for U10 and theta_w are set at 0. If these defaults are not changed, it is not possible to carry out a SWAN run with the “Quadruplets activated” (see physical processes in SWAN). *Name of main SCO file: NZ_STORM.SCO UNIBEST *(MORSYS/UNIBEST)



10 *total number of wave conditions *Hm0 *(m)

Tp (s)

theta (N^o)

ms (-)

H0 (m)

U10 (m/s)

theta_w (N^o)

1.0 5 330 2 0.2 0 0 1.5 5 330 2 0.2 0 0 3.0 8 330 2 0.2 0 0 2.0 6 330 2 0.2 0 0 2.5 7 330 2 0.2 0 0 1.0 5 30 2 0.2 0 0 1.5 5 30 2 0.2 0 0 3.0 8 30 2 0.2 0 0 2.0 6 30 2 0.2 0 0 2.5 7 30 2 0.2 0 0 In the Delft3D interface input for the Wave Run (Figure 5.3) can be defined, or an existing run can be started. Reference is made to the Delft3D manual. In the Delft3D interface relevant input on grid, bathymetry, physical parameters and numerical parameters and wave input file is linked to the run. The Delft3D interface also provides the options for modelling the effect of structures on the waves. Note : A code should be given to each wave condition, for inspection in GPP (for inspection). These codes must be given in Delft3D under “tidal information”, for example as indicated below (10 different “time steps” which represent a code for the 10 wave conditions in the above md-vwac file). The run can not be carried out without these codes.

Figure 5.3



The results of all wave computations are written to one hwgxy/wavm-file with the run-identification given by the user. The results from the hwgxy/wavm -file can be inspected with GPP.

5.1.3 LOCAL SCENARIO FILES: Link to select relevant wave data from the HWGXY/WAVM file

After selection of tab “Local Scenario Files” output points can be defined/selected and local .SCO files can be generated in the selected output points.

Figure 5.4

Additional information: • Nefis File HWGXY/WAVM Browse…, by pressing this button the user can select the

HWGXY/WAVM definition file from which the relevant wave data for UNIBEST CL+ are read.

• Type of Peak Period (Tp), As UNIBEST CL+ uses the Tp value in the scenario file the user has to select the method to calculate the Tp value. There are two options possible one Tp is retrieved from the NEFIS files directly (option “Use Tp calculated by SWAN”) or derive Tp from Tm01 by using the standard peak enhancement factor γ = 3.3. (option “Use Tp calculated from Tm01). However for a HWGXY file only the option “Use Tp calculated from Tm01” is possible because the Tm01 is the only parameter written to the NEFIS file.

• Load, by pressing this button the user is able to load a location file. This location file has the following format:



* info string n [number of locations] * info string x1 y1 name x2 .y2…name … … xn .yn…name

• Save as…, by pressing this button the user is able to save the locations (x,y) plus names to a specified file.

• Insert, by pressing this button a new row will be inserted above the selected row. • Delete, by pressing this button the selected row will be deleted. • Location table, the table shows the X,Y value of a location point. The column

“Accepted” indicates whether or not the interpolation has been done successfully. • Create Local Scenario Files, by selecting this button the local .SCO files are created in

the requested output points. The wave height, period and direction in the output points are read in the HWGXY/WAVM-file, and transformed to suitable parameters Hs, Tp, θ for UNIBEST CL+ via the subroutine perpar. Tmo1 is transformed to Tp via subroutine perpar with standard peak enhancement factor γ = 3.3. Wave directions in Cartesian convention are transformed to Nautical convention. If the interpolation is done correctly the “Accepted” value of a point will be checked. One of the reasons a point is not accepted, can be the fact that the value zero is used for none defined cells!! The output locations are written to an annotation file locations.ann. In GPP the location of these points in the bathymetry can be inspected visually. For a quick but limited check of the output locations a file check.chk is created. In this file the water depth at the output points is presented to enable the user to check the water depth at the output point.

(Note: Also the option of reading the data for Unibest from the com-file has been developed. However, if only Delft3D-waves is applied, the results of the wave computations are not written to the com-file, but to the hwgxy file only. In addition, the definition of the wave angle in the com-file is more complex). By pressing the buttons “Ok”the window will be closed and nothing is saved. By pressing the “Help” button will open the help file.

5.2 Unibest CL+ & Flow

(Optional Unibest CL + functionality) Not yet finished

5.3 Unibest CL+ & ARGOSS

(Optional Unibest CL + functionality)



5.3.1 Introduction

The company ARGOSS has a database with wave climate information all over the world, both offshore and near shore. The basis for the wave climates are satellite data which are transformed to wave spectra with mathematical models developed by ARGOSS. For more information on the method used go to the ARGOSS web page www.waveclimate.com. These wave climates can be bought in various ways. The most common option is by means of internet on the site www.waveclimate.com. However, there is another option offered by the program called DelftClimSAT that is described in this manual. With this program you can ask for climates at specific user supplied positions all over the world. The program sends a request by e-mail to a special e-mail address of ARGOSS. The request itself is done with a file that is sent as an attachment to the e-mail. The answers from ARGOSS are also sent by e-mail as attachments. The communication language used for these files is XML (Extended Mark-up Language) which is a de facto standard.

5.3.2 Request for (a) wave climate(s)

As stated in the “Introduction” it is possible to buy wave climates from ARGOSS. The principle is that you pay for each climate you purchase. ARGOSS offers two options: Buy vouchers: you can get as much climates as you want until the amount of your vouchers is reached. Subscribe to ARGOSS wave climate: you can get as much wave climates during the validity of the subscription. To be able to get climates you must have a user-id and a password assigned to you by ARGOSS and you can get the climates via the internet site given in the introduction. To get a first idea of what data is available, go to the site in demo mode. The help at this site will tell you more about validation and so on. The same principle of buying wave climate data is used with DelftClimSAT. However, a request is prepared by you with the help of the program and it is sent to ARGOSS by e-mail. Additional to the wave climate information you will get information about the tide. With this type of request you will get scatter data for a combination of classes of Hs, Tm and wave direction. The scatter data gives the number of times a combination has occurred. Program DelftClimSAT itself has three types of usage:

a) Stand alone to get a wave climate from ARGOSS. b) Stand alone to check the state of requests. c) Both options from within program UNIBEST.

The main difference between options a) and b) and option c) is the selection of the current directory. In options a) and b) the user must select the directory, in option c) the current directory is the directory with the model in use by UNIBEST. In the remaining of the manual only options a) and b) are described. Option c) is shortly described in the manual of UNIBEST with reference to this manual.



5.3.3 Initialisation

To be able to do a request for a wave climate the program needs information from the ARGOSS.ini file. Username: the user-id, supplied to you by ARGOSS, being the name under which you are registered at ARGOSS. Password: the password given to you by ARGOSS to check for the status of the vouchers or the subscription which allows you to get climate data. E-mail: the e-mail address where your request for a climate must be sent to. This address will be given to you by ARGOSS. Account e-mail: when your company has bought vouchers or has subscribed it is possible that requests are done by various persons. In that situation your company may want to keep track who really buys data. ARGOSS will sent an overview of the costs for your request to this mail address and also to the e-mail address where the request is sent from. The argoss.ini file may look as follows:

[ARGOSS] username=WLDELFT password=LV3721MS [email protected] [email protected]

This ini file must be available in the directory where you installed DelftClimSAT at the set-up. The file is created during set-up, but the items are not filled in, this must be done by you. You are free to create or edit this file as many times as needed. It is possible to use program DelftClimSat and create a request xml file without sending an e-mail. For that reason the E-mail line must be set to:

E-mail=no e-mail

5.3.4 Requests with program DelftClimSAT

5.3.4.1 Start the program within UNIBEST CL+ Graphical User Interface

To run the program within the UNIBEST CL+ user interface press the menu option “Tools|Wave Climate|Argoss Request” to start the program Request of DelftClimSAT.



Figure 5.5

5.3.4.2 Start the program without UNIBEST CL+ Graphical User Interface

To run the program click on START in the task bar and then press run. The next window will pop-up:

Figure 5.6

Here you have to type in the program name (DelftClimSAT) with its path or browse for the program. If you just give the executable name the next window is made active: Both options, get a climate and the checking of request status can be seen now. Checking the status is available with menu GetClimate. This option is described in chapter “Status of the requests.” To be able to ask for a climate you first must do the Model selection to get a UNIBEST model directory. Then menu Wave climate is enabled and you can fill in the form to do a climate request with the model directory as the current directory. If you want the fill in the request form for a directory free to choose you have to add two parameters

1. The first parameter is a fixed one: “-climate” 2. The second parameter must be the directory where you want to work



Example: suppose you want to work in the directory D:\myProject and the program is in the directory C:\programs then the run window must look like:

Figure 5.7

By pressing OK the program starts and will show the window as given in the next paragraph.

5.3.4.3 Fill in the form for request

The moment the program is started as described in the previous paragraph the next window pops-up:



Figure 5.8

This is the initial window when the directory was not used before by the program. Whenever you stop the program the file look-up.wcl is created or opened and the present status is saved to this file. The next time you start the program that last status is filled in. In the Project information box all fields must be filled in: Applicant name: the name of the person who makes the request. Project code and request ID: any string of characters that gives a unique identification of the request of the user. File to order with: the name of a file where the request is stored to and that is send as an attachment to the ARGOSS e-mail address. The extension of this file is set to XML, because the communication language used is XML. Account e-mail: this is the e-mail address as given in the ARGOSS.ini file. It can not be changed with this program. The climate data is given as scattered data for combinations of Hs, Tm and Wave direction. In the box Classification these classes are set default the first time a directory is used: Hs: .2 m



Tm .5 s Direction: 100 You are free to set different classifications in this box. It is possible to sent a message along with the e-mail, you can type this in the area under Send new message along with the e-mail. In some occasions you have to give coordinates in Lat/Long. It is possible to select the way you want to give them with the options in the box Lat/Long definition. A description of the options: degrees, minutes, seconds: three fields, one for degrees, one for minutes and one

for seconds degrees, decimal minutes: two fields, one for degrees and one for decimal minutes decimal degrees: one field for decimal degrees The option holds for all latitude and longitude figures. In the box Check the option for the climate type you can select a climate type. At any moment it is possible to switch from one option to another. All information during these switches is remembered. It is also remembered when you exit the program. From hereon a description of the options is given. When you fill in a numerical field you may accidentally type a character that is not allowed in numeric data. That moment the field is coloured red. A message is shown: “Wrong character so it is no value.” In the next part of the form an example is shown:

Figure 5.9

The moment you correct it, the field is coloured white again.



Climate in an ARGOSS grid point

Figure 5.10

The climate in a predefined ARGOSS position is selected. You have to give the Lat/Long coordinates as described before and N(orth) or S(outh) and E(ast) or W(est). The closest point where a climate is available is selected. The results are available climate data already prepared by ARGOSS with its mathematical models. The fields are filled in as follows:



Figure 5.11

and the file Z3458-grid.xml is send to ARGOSS when the button Send E-mail is pressed. An overview of the file: <?xml version=" 1.0 " encoding="iso-8859-1";> !DOCTYPE wlrequest SYSTEM "ArgossWL.dtd"> <wlrequest> <date>05/04/2004 14:28:58</date> <licence>ARGOSS,WLDELFT,LV3721MS</licence> <applicant>Lou Verhage</applicant> <project>Z3458-grid</project> <account-mail>[email protected]</account-mail> <class>.2,.5,10</class> <request-option>deep</request-option> <grid>10 1 1 N,20 2 2 E</grid> </wlrequest>



Climate from satellite area

Figure 5.12

With this option there is also a position given. As an example, the decimal minute option is used. The position is used to select an area with satellite data where the position is in. The file Z3458-sat.xml is now send by e-mail. The contents of this file: <?xml version=" 1.0 " encoding="iso-8859-1";> !DOCTYPE wlrequest SYSTEM "ArgossWL.dtd"> <wlrequest> <date>05/04/2004 14:34:05</date> <licence>ARGOSS,WLDELFT,LV3721MS</licence> <applicant>Lou Verhage</applicant> <project>Z3458-gridsat</project> <account-mail>[email protected]</account-mail> <class>.2,.5,10</class> <request-option>deep</request-option> <satellite>10 1.1 N,20 2.2 E</satellite> </wlrequest>



Climate in user defined positions

The two previous options were fixed ARGOSS positions. A user can give positions in his own coordinate system and at positions the user selects. The two options that can be used are Climate in a local area and Climate in local points. For both options the next part of the window is used:

Figure 5.13

Here the user links his coordinate system (Local X and Y) with the World coordinate system in Lat and Long. This is used to express all user coordinates in the UTM (Universal Transverse Mercator) coordinate system.

Climate in a local area

Once the user has connected his coordinate system to the world it is possible to set an area where the user wants a climate. For that reason two coordinates are needed: the LL corner of the area, meaning X- and Y-coordinates of the Lower Left point. the UR corner of the area, meaning the X- and Y-coordinates of the Upper Right point, being the opposite corner of the LL point. In the next window these positions are filled in in the Local extent coordinates box. The name of the file to order with is changed in Z3458-area. This is also done for the identification, but it could have been any other ID. When the button Send e-mail is pressed the file Z3458-area.XML is created and send to ARGOSS.



Figure 5.14

The contents of the file Z3458-area.xml: <?xml version=" 1.0 " encoding="iso-8859-1";> !DOCTYPE wlrequest SYSTEM "ArgossWL.dtd"> <wlrequest> <date>05/04/2004 14:57:58</date> <licence>ARGOSS,WLDELFT,LV3721MS</licence> <applicant>Lou Verhage</applicant> <project>Z3458-area</project> <account-mail>[email protected]</account-mail> <class>.2,.5,10</class> <request-option>deep</request-option> <xylocal>10,100</xylocal> <latlon>20.3 E,5.7 N</latlon> <UTM> 34 N 422488.1 630089.1</UTM> <extent> <coordinate position="LL"> 422478.1, 629989.1</coordinate> <coordinate position="UR"> 423478.1, 630089.1</coordinate> </extent> </wlrequest>



Climate in local points

With this option it is possible to ask for a climate in specific points. The ARGOSS model then computes the climate for this point from the data available in the data base.

Figure 5.15

With this option the box Local climate point coordinates is visible and is used to set the positions where a climate is found. In principle the number of positions is free. What do you see in the given window? In the List of points you see one point activated. In Point three items must be filled in: the X- and Y- coordinate of the point and the depth at that point. The moment all fields are filled you can Add this point to the List of points, it is activated. Pressing cancel means that the Point fields are cleared. You can continue this process until all your points are defined. ARGOSS only computes for full depth values. For instance, if you fill in the depth 1.6 then ARGOSS uses depth is 2. It is possible to handle the information in the box List of points. You have to click on a line in the list and the buttons Remove and Edit are enabled:



Figure 5.16

When you press Remove you are asked whether you really want to remove this point. When you agree the line is removed. When you press Edit the content of the line is shown in the Point fields:

Figure 5.17

The button Add has been changed to Edit OK. This last button is enabled the moment you change one of the values in the Point fields. You can always Cancel the edit. When you did any changes and you press Edit OK the highlighted line is replaced with the new information and the Point fields are made empty. With the button Clear list you remove all lines in the List of points after confirmation. When the button Send e-mail is pressed the file Z3458-point.XML is created and it is sent to ARGOSS. (This button is not enabled when one or more of the Point fields hold values.) When you press the Send e-mail button an additional action is taken: a coast line is searched for. The idea behind this is that you give near shore positions, sometimes very close to the shore such that this shore may influence the climate locally. For instance, when a position is

WL | Delft Hydraulics 1 0 0


in a bay some waves at deep water may not reach the position because some wave directions are such that this is impossible. Now there are two possible situations: DelftClimSAT is started in UNIBEST mode. In this case the file model.mda is searched for and the coast line is read from this file (model is the name of the model selected in UNIBEST). When this file is not found in the model directory you will be warned and the e-mail is not sent. You must first take care that there is an appropriate mda file available in the directory. It is best to stop the program DelftClimSAT and to handle this problem. You started DelftClimSAT yourself. Now you must tell the program what file has the coast line. For that reason a window pops up in which you can select a file from wherever you want. When you select a file with the extension mda this file is used as in situation 1, it is assumed it is a UNIBEST file that contains the coast line. When you select another file the contents must be simple: each line must hold the X- and Y-coordinate of one point of the coastline. All values must be in the user coordinate system. At least two points are needed; the total number of points is free. The last option is used to give an example. The file coast1.txt was created and holds two points: 200,300 400,500 As a result the next xml file is created and is send to ARGOSS. <?xml version=" 1.0 " encoding="iso-8859-1";> !DOCTYPE wlrequest SYSTEM "ArgossWL.dtd"> <wlrequest> <date>06/04/2004 13:32:47</date> <licence>ARGOSS,WLDELFT,LV3721MS</licence> <applicant>Lou Verhage</applicant> <project>Z3458-point</project> <account-mail>[email protected]</account-mail> <class>.2,.5,10</class> <request-option>climate points</request-option> <xylocal>10,100</xylocal> <latlon>20.3 E,5.7 N</latlon> <UTM> 34 N 422488.1 630089.1</UTM> <coast> <coordinate> 422678.1, 630289.1</coordinate> <coordinate> 422878.1, 630489.1</coordinate> </coast> <climate-points> <xyz><coordinate> 422483.1, 629997.1</coordinate>, 3</xyz> <xyz><coordinate> 422508.1, 630989.1</coordinate>, 2</xyz> <xyz><coordinate> 422545.1, 630077.1</coordinate>, 2</xyz> </climate-points> </wlrequest> The tag <coast> holds both coast positions from file coast1.txt, the tag <climate-points> holds the three points where the user asked a climate for. In both cases the coordinates are transferred to the UTM coordinates



5.3.5 Status of the requests with program DelftClimSAT

When a request for climates is done there are three moments: The user sends a request. A first reaction from ARGOSS telling the applicant whether the request is accepted or not. When the request is rejected a reason for this is given. This reaction will follow as soon as possible, at least within two hours. The final reaction. In this reaction the user will get the climates asked for or a message is sent with a motivation why a climate is not delivered. When climates are asked for in more positions it is possible that the climate is not given for all these positions.

5.3.5.1 Start the program within UNIBEST CL+ Graphical User Interface

To run the program within the UNIBEST CL+ user interface press the menu option “Tools|Wave Climate|Argoss Check Request” to start the program Status of DelftClimSAT.

Figure 5.18

5.3.5.2 Start the program without UNIBEST CL+ Graphical User Interface

This option can be activated from UNIBEST or from the Start at the task bar with Run. In the UNIBEST mode the current directory is set to the model directory. In the Start option the UNIBEST mode and can also be made active, just give the executable file descriptor in the Open field.

Figure 5.19



and the next window pops-up:

Figure 5.20

When you first do the Model selection the current directory is set to the model directory; if not the current directory is used. When you activate menu GetClimate the next window is made available:

Figure 5.21

In this window the three boxes represent the three moments of request and reaction. You can also activate this window immediately with the Start menu:

Figure 5.22



An overview of the request status

Now, with the button Get Request Info you can select a request XML file you have sent to ARGOSS. If you select a file that is not a correct xml file the next information is given:

Figure 5.23

If you select a correct request file it is possible that the first reaction is not yet available:

Figure 5.24



Figure 5.25

Now the second box gives the information about the file found and the Order Id supplied by ARGOSS. There is no message so the request is accepted. At this moment there is no query result, one or more climates received, at least it is not found in the directory of the “request received” file. When you are quite certain there is a query result you can look for that file by pressing the button Look for file. The connection between a “request received” file and “query result” file is the Order id that is uniquely assigned by ARGOSS. If the file is not available yet one must wait for the next reaction from ARGOSS. This reaction will also come from ARGOSS by e-mail and you have to store the “query result “ file in the directory where the request file itself is stored. This also holds for the “request received” file. The moment the “query result” file is found the window looks as follows:



Figure 5.26

It says the climates are available and the “query result” file is given. Also presented is the overview of returned climates. For the climate that is highlighted (Climate # 1) the request option is given. In the example this is point with the coordinates as given. The Classification is the same for all climates, whereas the Tide parameters will be different for each climate. The file itself holds the information: <?xml version="1.0" encoding="iso-8859-1"?> <!DOCTYPE queryresult SYSTEM "ArgossWL.dtd"> <queryresult> <date>22/01/2004 13:06:48</date>



<applicant>Lou Verhage</applicant> <project>Z3458-cp6</project> <account-mail>[email protected]</account-mail> <orderid>WLDELFT1074762789</orderid> <request>accepted</request> <climate-result COUNT="2"> <climate TYPE="POINT" UTME="408837.5" UTMN="2956295"> <class>.2,.5,10</class> <tide DEPTH="2"> <level REFERENCE="MSL" MIN="-1.03" MAX="0.95" RMS="0.45"/> <velocity MAX="0.47" RMS="0.21"/> </tide> <climate-source TYPE="nearshore"> <nearshore COASTNORMAL="42" DEPTH="2" LATEXTENT="26.45,26.9"

LONEXTENT="49.9,50.3" URL="http://www.argoss.nl/morfologie/location_point1.gif"/>

<origin NAME="model" LON="50.25" LAT="26.75"/> </climate-source> <climate-data NRECORDS="359"> 0.10, 3.75,-10,2; 0.30, 3.75,-10,1; 0.10, 3.75,0,9; 0.10, 4.25,0,1; 0.30, 3.25,0,1; 0.30, 3.75,0,3; …………………area removed for presentation purposes…………………… 0.50, 3.25,100,1; 0.50, 3.75,100,2; 0.50, 4.25,100,1; 0.90, 5.75,100,1; 0.90, 6.25,100,2; 1.10, 4.75,100,1; </climate-data> </climate> <climate TYPE="POINT" UTME="4111123.5" UTMN="2953815"> <class>.2,.5,10</class> <climate-source TYPE="nearshore"> <nearshore COASTNORMAL="60" DEPTH="2" LONEXTENT="49.9,50.3"

LATEXTENT="26.45,26.9" SHELTERFROM="10" SHELTERTO="118" URL="http://www.argoss.nl/morfologie/location_point2.gif"/>

<origin NAME="model" LON="50.25" LAT="26.75"/> </climate-source> <climate-data NRECORDS="341"> 0.10, 3.25,20,2; 0.10, 4.75,20,3; 0.30, 3.25,20,1; 0.10, 3.25,30,216; 0.10, 3.75,30,344; …………………area removed for presentation purposes…………………… 0.90, 4.25,100,1; 0.90, 4.75,100,1; 0.10, 2.25,110,1; 0.90, 5.25,110,1; </climate-data> </climate> </climate-result> <tide DEPTH="2"> <level REFERENCE="MSL" MIN="-1.00" MAX="0.93" RMS="0.44"/> <velocity MAX="0.49" RMS="0.21"/> </tide> </queryresult>

At the position of area removed for presentation purposes there are much more climate data lines in the original file. For the highlighted climate it is possible to create a UNIBEST climate file by pressing the button Create. You are invited to select a directory and give the file to be created a name. The extension of the file is automatically set to .sco. An example of such a file:



360 (Number of days) 359 (Number of waves Location: X=-8227 Y= 8354) HWGXY H0 wave height period direction Duration 0.00 .1 3.75 -10 1.386963E-04 0.00 .3 3.75 -10 6.934813E-05 0.00 .9 3.25 -10 6.934813E-05 0.00 .9 4.75 -10 6.934813E-05 0.00 .1 2.75 0 6.934813E-05 0.00 .1 3.25 0 3.467406E-04 0.00 .1 3.75 0 6.241332E-04 0.00 .1 4.25 0 6.934813E-05 0.00 .3 3.25 0 6.934813E-05 0.00 .3 3.75 0 2.080444E-04 0.00 .5 3.25 0 6.934813E-05 …………………area removed for presentation purposes…………………… 0.00 .7 4.25 100 2.773925E-04 0.00 .7 4.75 100 1.386963E-04 0.00 .7 5.25 100 6.934813E-05 0.00 .9 5.25 100 6.934813E-05 0.00 .9 5.75 100 6.934813E-05 0.00 .9 6.25 100 1.386963E-04 0.00 1.1 4.75 100 6.934813E-05 1 (Number of Tide conditions) DH Vgety Ref.depth Perc .45 .21 0 100

in which the number of occurrences in a class is transformed to a percentage of occurrences per year. To create files for all climates this must be repeated for each climate.

5.3.6 Transform ARGOSS climates

Once you have received a climate file from ARGOSS you can transform this file to your needs. In the previous chapter we described how to make climate files for UNIBEST. There are two options for you to create additional types of climate files that suits to your environment: Design software that reads the “query result” file and store it in the format you need. Ask WL|Delft Hydraulics for an offer without engagement to add software to program DelftClimSAT that does this transformation that can be activated by an additional button. This will be a special delivery for your use only. Of course it is also possible to do your own statistics on the received climates, but this is beyond the scope of program DelftClimSAT.



Theoretical Manual 6

6.1 Introduction

This manual serves as the Theoretical Reference Document for operating of the UNIBEST Coastal Software Package. UNIBEST is an acronym of UNIform BEach Sediment Transport. The Software Package has been developed in order to yield an integrated modelling package with diagnositc and prognostic capabilities in the study and simulation of longshore and cross-shore sediment transport processes and related morphodynamics of beach profiles and beach planform shapes (coastline evolution). The UNIBEST Coastal Software Package consists of four separate modules, as follows:

• UNIBEST-CL :an acronym for UNIform BEach Sediment Transport - CoastLine Dynamics .

• UNIBEST-LT : an acronym for UNIform BEach Sediment Transport - Longshore Transport,

• UNIBEST –TC: an acronym for UNIform BEach Sediment Transport – Time dependent Cross-shore Transport,

• UNIBEST-DE : a module for Dune Erosion during storm surges. Basic input data for the UNIBEST-CL module are generated by the module UNIBEST-LT. Results ofUNIBEST-TC can be introduced in the UNIBEST-CL module. By doing so users can compose their own quasi-3D-like coastal model. The integrated UNIBEST Coastal Software Package is a very powerful, yet easy to operate engineering tool. The Software Package comes with a flexible and menu-driven interface which is userfriendly. It has on-line context-sensitive help facilities, the model input data are checked on consistency and out-of-range values. In case parameters are unknown default values are entered. On running the computations model results are presented graphically. In addition, the package comes with facilities to prepare high-quality color graphics which can be sent off-line to many different hardcopy output devices. Results can also be obtained in Ascii format allowing the application of other post-processing software. The structure of UNIBEST is very flexible, enabling the users to cope with a wide range of problems, be it a simple transport computation or a detailed coastal zone management study. The latter may involve the analysis of erosion counteracting measures, their conceptual design and the impact assessment on areas lying close to the area under study. In the present report the physical concepts and modelling techniques of the UNIBEST Coastal Software Package (UNIBEST-LT and UNIBEST-CL modules) are dealt with. Moreover, the methodology for use of these modules is described on the basis of three case studies which cover the various types of analysis options of the package in coastal morphology studies.



6.2 Capabilities of UNIBEST

The UNIBEST coastline model (UNIBEST-CL) is a general purpose engineering tool that can be applied for simulation the response of the nearshore zone of the shoreface where effects of wave breaking and wave-driven longshore currents in combination with alongshore directed tidal currents are predominant. The model allows simulation of coastline response occurring over a period of months to decades in the course of its approach to an equilibrium under the imposed wave and current conditions, boundary conditions, initial coastline shape and the configuration of coastal structures, and other input parameters. The model is best suited in situations where gradients in the longshore sediment transport capacity are responsible for the imbalance in sediment supply to and transport from the considered area, resulting in erosion and coastline retreat or shoaling and coastline accretion. The imbalance can be part of a natural pertubation, or can be evoked by human interference. Examples of the latter case are sediment trapping structures which generally cause the downdrift coast to erode. UNIBEST can be applied to various types of coastal erosion problems of which the spatial and temporal scales may change. The following specific examples of problem analysis options can be distinguished: • large scale problems, • medium scale problems, • small scale problems. Large scale coastal evolution problems, involving a spatial scale of hundreds of kilometres and a temporal scale of decades, are focussed on global sediment budget analysis and the corresponding alongshore sediment transport rates. Changes may evolve as mean trends, fluctuations and may have an asymptotic character. The changes may be caused by long-term natural changes in boundary conditions (e.g. the reduction of the sediment supply from a river). In applications at medium scale, the impact on the coastal system of coastal defence measures and other engineering structures (e.g. harbour moles) can be determined on a wider scale. Relative effects can then easily be compared. Typical length scales of the problems at this scale are in the order of tens of kilometres, while typical time scales are in the order of a few decades. In small scale applications the local effects owing to coastal defence measures such as groynes, revetments, (offshore) breakwaters and the execution of beach nourishments, are studied in more detail. The changes are governed by local geometry and hydromorpho-dynamic conditions. The length scales are limited to only a few kilometres, while typical time scales are usually a decade (or less). This group of application is typically used for detailed design of coastal engineering structures. The UNIBEST Coastal Software Package may thus be used for study and analysis of feasible erosion control measures as well as for their conceptual design (dimensioning, spacing) and impact assessment on adjacent coastal stretches. In principle, the UNIBEST coastline model can not be used to simulate short-term fluctuations of the coastline in which no evident trend in the position of the coastline can be detected. Examples of short term coastline dynamics are the development of summer-winter



profiles (seasonal effects), rhythmic beach patterns and stone-induced beach erosion in which crossshore sediment transport processes are dominant. However, coastline changes induced by cross-shore sediment transport associated with storms, or seasonal beach profile dynamics (derived from the module UNIBEST-TC) can be simulated in the UNIBEST coastline model in a schematized way via the option 'sediment sources and sinks' in the program. For coastline changes dominated by tidal currents and local scour around structures, the UNIBEST model can also no be applied.

6.3 Short description of UNIBEST

6.3.1 Unibest LT

UNIBEST-LT is designed to compute tide- and wave-induced longshore currents and sediment transports on any beach of arbitrary profile. The tidal current is introduced as a tidal current velocity at a reference depth. In UNIBEST-LT the surf zone dynamics are computed by a built-in random wave propagation and decay model (Battjes and Stive, 1984). The model transforms offshore wave data to the coast, taking into account the principal processes of wave energy changes due to bottom refraction, shoaling and dissipation by wave breaking and bottom friction. The wave model has been applied to an extensive set of data for the purpose of calibration and verification. Both laboratory and field data were used, obtained on beaches with a more or less plane slope as well as on barred beaches, and for a wide range of wave conditions. In the model the longshore current distribution across the beach profile is derived from the momentum equation alongshore taking into account bottom friction, the gradient of radiation stress and the tidal surface slope alongshore. A semi-analytical description of the wave induced, depth-mean longshore current is used, derived through the breaking wave dissipation and using a linearized version of the bottom friction term for wave and current combined (see e.g. Thornton and Guza, 1986). Longshore sediment transport rate and its cross-shore distribution can be evaluated according to several total-load sediment transport formulae for sand or shingle, which enables a sensitivity analysis for local conditions. The choice of transport formulae depends largely on the particular conditions of the situation to be studied and the nature of the sediment being considered (either sand or shingle). However, all sediment transport formulae are based on the physically fundamental concepts that the transport is a phenomenon with a threshold of motion and there is a maximum capacity that the flow can carry. However, the sediment transport is assumed to respond to the local wave and current conditions in an instantaneous, quasi-steady way (potential transport capacity = equilibrium transports). This assumption remains valid as long as the differences between the local true sediment transport and the local equilibrium transport is relatively small and the adjustment length scale ofthe sediment transport process (relaxation effect) is smaller than the maximum horizontal grid size which is applied in the UNIBEST model.



The littoral transport can be represented on a user-defined grid which can be adapted depending on the particular conditions of the situation to be studied. At each gridpoint the sediment transport rate is computed for the local hydraulic conditions. The following sediment transport formulae can be invoked:

CERC (1984),

Engelund-Hansen (1979),

Bijker (1967, 1971),

Van Rijn (1992),

Bailard (1981),

Van der Meer-Pilarczyk (1992). In Section 6.12 a detailed description of the sediment transport formulae is given. The computational procedure may take into account any predefined wave climate and tidal regime in order to enable an assessment of gross and yearly transports, seasonal variations and storm events.

6.3.2 Unibest CL

UNIBEST-CL is designed to compute coastline changes due to longshore sediment transport gradients of an alongshore nearly uniform coast, on the basis of the single line theory, which was first presented by Pelnard Considère (1956). In this theory the coast is schematized into a single line and the displacement of this line is described as a function of time and longshore position. The dynamic area of the bottom profile moves in parallel to itself without changing its shape during the process of erosion or accretion. Various initial and boundary conditions may be introduced as to represent a variety of coastal situations. Along the coast sediment sources and sinks (time dependent) may be defined at any location, to simulate river sediment supplies, the effect of subsidence, offshore sediment losses and beach mining. UNIBEST-CL is capable of modelling the morphologic effects of various coastal engineering measures, such as headlands, permeable and non-permeable groynes, coastal revetments and seawalls, breakwaters, harbour moles, rivermouth training works, artificial sand by-pass systems, and beach nourishments. The effect of wave shielding (diffraction, directional spreading, wave transmission) behind coastal structures can be incorporated in UNIBEST-CL. To this effect, the model has two utility programs called SHOWTS and STRUCT. These can be used by the user to modify the sediment transport distribution of any single wave and/or flow condition along parts of the coast. The coastline respons to such modifications can be studied, enabling the user to assess in a very realistic way the coastline developments of curved or sheltered coastal stretches.



The basic input data for the UNIBEST-CL module comes from the UNIBEST-LT module. The modules are connected through a dedicated output/input link via file transfer with UNIBEST –LT transport computations are performed for a number of coast angles, coverning the range of wave angles in the wave scenario. Changes induced by cross-shore sediment transport which go with seasonal or longterm beach profile dynamics and come from the UNIBEST - TC module which is incorporated in UNIBEST-CL. They can be entered as time-dependent sediment sources and sinks along the area under investigation. In this way a quasi-3D-like coastal model can be create.

6.4 Basic assumptions of single-line theory

The UNIBEST coastline model is based on the single line theory which was first presented by Pelnard- Considère (1956). The theory of Pelnard-Considère gives the basic equations describing the mórphological processes of coastline evolution due to longshore sediment transport gradients. These equations lead to the well known diffusion equation. Both initial and boundary conditions are needed to solve this equation for aspecific problem (e.g. see Figure 6.1: accretion against impermeable breakwater).

Figure 6.1, accretion against impermeable breakwater

For the single line theory the coastal profile is schematized according to Figure 6.2. The x-axis is chosen along the original coastline. The shore-normal y-axis is chosen in a direction parallel to the original coastline pointing in offshore direction to create a right-hand coordinate system (Figure 6.2a). The profile characterizing the beach to be studied is assumed to move horizontally over its entire active profile height as a result of erosion or accretion (Figure 6.2b). The beach slope therefore does not change. Beyond the active profile height the bottom does not move. The shoreward limit of the profile changes is located at the top of the active profile. This is the most fundamental assumption of the single line theory. Important implications of this



assumption are that only longshore sediment transports can be taken into account and that the beach profile is always in equilibrium. In order to simulate the coastal changes a continuity equation and an equation of motion are used together with initial and boundary conditions. The equation of continuity can be derived from Figure 6.2a and Figure 6.2b:

0sp

Qyht x bq∂∂

+ + =∂ ∂

(1.1)

where:

sQ :total longshore transport

y :coastline position

ph :active profile height

bq :sediment source/sink

Figure 6.2, Schematisation of single line theory

The equation of motion can be drived from Figure 6.2c by assuming that the longshore transport is a (continuous) function of the coastline orientation. This leads to:



0

22

0 02

1( ) ( ) ( ) ....2

s ss s

Q QQ Q θ θθ θ θθ θ= =

∂ ∂= + +

∂ ∂+ (1.2)

With the assumption that second order and higher terms can be neglected this can be simplified to:

0 0( ) ( )s

s sQQ Q θθ θθ =

∂= +

∂ (1.3)

When defining:

1sdQytg and s

x dθ θ

θ∂

= = −∂

= (1.4)

Equation (1.3) yields:

0 1( )

ssdyQ Q sdx

θ = − (1.5)

where

( )sQ θ :longshore transport as a function of the coastline direction

0sQ :longshore transport along a straight coastline parallel to the x-axis

1s :variation of the transport as a function of coastline orientation.

θ :coastline orientation with respect to the x-axis Equation (1.5) is known as the equationof Pelnard- Considère. When the equation of motion is substituted in the equation of continuity the following equation is obtained (with constant

0sQ and and =0): 1s bq

2

12

p

sy yt h x

∂ ∂=

∂ ∂ (1.6)

This is the so-called diffusion equation for which analytical solutions can be found (Bakker and Edelman, 1965; Bakker, 1969). In UNlBEST the change of the transport rate due to a reorientation of the coastline (parameter in equation (1.6) is approximated by computing the transport 1s sQ on the basis of the offshore wave climate, for a number of coastangles. This implies that in UNIBEST the so called 'coastal constant' has not a single constant value but that it is reproduced as a function of which the value depends on the actual orientation of the coastline. This function is approximated by an exponential function (see Section

1s

6.6). The advantage of a numerical approach is that solutions of the complete equation, without the above simplifications are possible. Moreover , to describe a realistic situation involving



a general erosion problem it is necessary that q 0b ≠ , that 0sQ and are functions of x, and

that time-varying wave conditions can be handled. bq

Several investigators have presented numerical models for the simulation of coastline changes using the single line theory. Among them are Rea and Komar (1977), which used a technique for simulation of coastline changes of a hooked beach represented on a two-dimensional grid, Perlin (1979), who discussed the coastline changes due to detached breakwaters, Le Mehauté and Soldate (1980) which verified an implicit numerical model using field data and Hanson (1980) who described the modelling system Genesis.

6.5 Required data to run UNIBEST

6.5.1 General

The UNIBEST model can be applied to carry out investigations into the morphodynamics of coastlines and to determine the suitability and efficiency of coastal protection or rehabilitation measures. Development of a solution and use of UNIBEST are based on physical data and quantification of the processes involved. Coastal erosion problems can be the result from forces of nature or action of man. The main forces by nature are:

• Waves and their longshore component of wave energy; • Tide induced currents and water level variations; • Water level changes like storm-surges and sea level rise; • Wind (transport on the dry beach); • Ground motion.

In many cases, natural developments have been disturbed by human interference, like dredging activities, construction of harbour moles, etc. Existing structures along the problem area and their effect on the coastline development should be known. The main effects of human interference are:

• Interruption of longshore transport by structures; • The change of shore current patterns by structures; • The change of the nearshore wave climate by structures; • Sediment dredging.

The first step of a UNIBEST project should therefore consist of the evaluation of the characteristics of the overall morphology of the site and adjacent coastline in order to establish the natural characteristics of longshore sand transport and to gain insight into active processes which may result in changes to the present coastline. The regional trend of the coast is determined from a wide-scale chart, whereas the trend of the local shoreline is determined from a small-scale chart.



Previous studies of coastal erosion along the area can be very helpful to gain the required insight. For longshore transport and coastline modelling purposes extra data have to be available. Apart from the analysis of the existing data, an additional measuring campaign may be deemed necessary to obtain the required data. In this connection it is observed that these activities should al ready be completed prior to a coastal erosion study. The data which should provide the required insight to carry out coastline computations for the area of interest are related to the following aspects:

6.5.1.1 Waves:

For the computation of the annual longshore transport and the possibly resulting coastline evolution, long-term wave-data for the area of interest are indispensable. Attention must be focussed on those aspects of the wave climate which has a bearing on the selection of a suitable intake. An important parameter for coastal morphology studies is the local wave climate. Data on local wave conditions are often not available. Therefore, the local wave climate has to be determined from wind data, the bathymetry of the area and the related fetches. Care must be taken that sufficient information is available to derive all relevant wave climates and dominant wave directions . For the wave data, the wave height, period and direction, and the water depth where the wave data were collected are important. The required data is referring to the specification and schematisation of the wave climate on the basis of time series or, at minimum, statistical summaries for a period of at least two years, if possible more than five years (including the period of hindcast). In a case where wave data obtained over a short period is available for the simulation it is necessay to check the meteorological characteristics during the required period before utilizing them. Coastline changes are very sensitive to wave directions because the equilibrium configuration of the coastline depends very much on the predominant wave direction, and this quantity is the most difficult to measure. Potential sources of the wave climate in the area of interest have to be reviewed (e.g. registered ships observations of sea and swell wave conditions, (directonal) wave recorder buoy measurements). Often the required information concerning the waves is insufficient, and therefore, available long-term wind data are extremely important as a supplement to the wave data. In such cases it may be possible to derive an offshore wave climate with a hindcast model from long period wind summary data recorded at a nearby meteorological station or airport. The effects of the coastal boundary layer and daily and seasonal trends in wind speeds, gustiness, and direction should be taken into account.



If the offshore bottom topography is very irregular or the project site is of wide extent, representative local wave climates have to be reproduced from wave propagation computa tions performed with a 2D wave propagation model especially suitable for application in coastal regions, to account for local variations in wave conditions along the coast. Owing to the wave filtering effect of the shallow shoals and banks in the foreshore significant differences can be found between the high water and low water wave climate. Therefore, the effect of water level variation on waves propagating towards the coast have to be incorporated.

6.5.1.2 Water levels:

To calculate the wave transformation and to determine the zone of sediment movement information on water levels is required. This information should relate to the water level variations due to the astronomical tide and the possible rise of above or lowering below normal water level due to wind and barometric pressure. Several statistical values of the tide level can be important. The tidal range characteristics for the site can be defined from the harmonic constituents obtained from the Admiralty Tide Tables or from an analysis of a one month duration tidal registration by means of a tide gauge. Water levels resulting from extreme storm events need to be quantified in order to quantify and evaluate the capacity of longshore transport resulting from extreme storm events.

6.5.1.3 Currents:

The sediment transport in the area seaward of the surf zone is often strongly influenced by tidal currents, so information on these currents is essential. Data on current velocities can be obtained by direct measurements or by use of numerical flow modeis. In situations with a mixed diurnal-semidiurnal character of the tidal wave and currents a water level current velocity c1assification has to be established. In many countries, coast and port authorities or the Admiralty can provide tables and charts of surface current velocities, observed in the vicinity of main shipping routes, river mouths and estuaries. For longshore transport modelling purposes tidal current velocity data can be taken from data recorded off the site.

6.5.1.4 Nearshore topography

A bathymetric survey of the offshore area and beach profiles (soundings and levellings) usually provides the main information regarding the morphological processes. Approximate position of the coastline as well as the intertidal and submarine foreshore topography.



6.5.1.5 Littoral drift:

Estimated net annual volumes of sand transported through the coastal sections on the basis of the ca1culated wave c1imate. Results of net annual wave induced transport for different incident wave directions representative for the coastal section off the site.

6.5.1.6 Sediment:

This information relates to the percentages of sand and other material, e.g. silt, sheIls, organie matter, and the grain size distribution of the sand fraction. collection of sediment samples from the seabed and the beach followed by a grain size analysis.

6.5.1.7 Rivers and other:

It is necessary to obtain information on the sediment volume discharged to the coast through the major river mouths. In general, however, it is rarely the case that these volumes have been determined by direct field measurements. Therefore, the discharged sediment volume must be inferred by some method in advance of predicting coastline changes. Not aH of the sediment discharged from a river directly contributes to the change in the coastline. A great portion may be deposited on a shoal in front of a river mouth, and a portion of the sediment, particularly the finer material, may be transported to the offshore zone. Therefore, only a small portion of the sediment volume discharged from rivers may directly contribute to coastline changes. In some cases, the volume of sand supplied to the foreshore or taken out of the foreshore by wind may be significant. On a wide beach where seasonal wind blows strongly, the volume of wind-blown sand supplied to or lost from the beach should be estimated. Apart from the data mentioned above, other information may be useful to obtain a c1ear view of the morphological processes in the area of interest. Examples of such information are visual inspections, interviews with local people, old photographs and aerial photographs of the coastal area. It is to be noted that no specific mIes can be given regarding the information which is required to study the morphological processes. In general, it can be stated that the quantity and quality of the data strongly determine the knowledge of these processes, and consequently this also applies to the quality of the coastline computations and the advice regarding the proposed coastal protection measure.

6.6 Mathematical physical description

6.6.1 Basic assumption

A beach of arbitrary cross shore profile with straight, parallel depth contours is considered, which is attacked by a random wave field, homogenous alongshore and obliquely incident, and by a tidal current, homogeneous alongshore in its current strength. In this situation the



sediment transport due to an alongshore flow induced by the waves and the tide is considered.

Figure 6.3

6.6.2 Governing equations

6.6.2.1 Wave propagation and breaking

The basic equations for the wave propagation and decay and the wave-induced cross shore water level set-up are as follows: The equation for wave energy balance:

cos 0fbg

r r r

DDd Ecdx

αω ω ω

+ + =

(1.7)

the equation for wave set-up:

0( )xx

d S g h ddx dx

0ηρ η+ + =

c

(1.8)

and Snellius law: sink α = (1.9) where c equals a constant value.



Figure 6.4

Figure 6.5

where: E wave energy per unit surface area defined as:

218 rmsE gHρ=

2[ ]MT −

rmsH root mean square wave height [L] ρ density of water 3[ ]ML− g acceleration of gravity 2[ ]LT −

rω relative wave peak frequency defined as: sin( )r k Vω ω α= −

1[ ]T −



ω peak frequency defined as: 2Tπω =

1[ ]T −

T wave period [T] α angle between wave direction and shore normal [-] V alngshore velocity 1[ ]LT − k wave number, on basis of the dispersion relation as

defined as: 2 tanh( )r g k kdω =

1[ ]L−

d water depth defined as:

0d h zη= + + − [L]

η wave set up [L]

0h still water level [L]

z bottom height [L]

gc group velocity of waves defined as:

r rg

nck k

δω ωδ

= =

1[ ]LT −

bD energy dissipation due to wave breaking defined as: 21 ( )

4 2r

b c bD g Q mHωρ απ

=

3[ ]MT −

bQ local fraction of breaking waves defined as: 2

1ln

b rms

b m

Q HQ H

−= −

[-]

mH depth limited wave height defined as: 0.88 tanh

0.88mkdH

kγ =

[L]

cα coefficient for wave breaking (order 1) [-] γ coefficient for wave breaking; a function of wave

steepness approximate values:

0 .01 .02 .03 .04

0.5 0.63 0.73 0.81 0.85

[-]

fD energy dissipation due to bottom friction defined as: 3

1/ 218 sinh( )

r rmsf w

HD fkd

ωρ π − =

3[ ]MT −

wf coefficient for bottom friction realistic value: 0.01 [-]

xxS radiation stress component defined as:

2 1(1 cos )2xxS E n α = + −

2[ ]MT −

n ratio of group velocity to wave velocity defined as: [-]

rmsHλ

γ



1 02 sinh(2 )

kdnkd

= + =

6.6.2.2 Currents

The basic equation describing the longshore current distribution is the momentum equation alongshore:

02 | |xy tot

dhd gS gd V Vdx dy C

ρ ρ 0+ + = (1.10)

Figure 6.6

where:

xyS radiation stress component defined as: cos sinxy yxS S E n α α= =

2[ ]MT −

totV velocity function in shear stress term defined as: 2 2

tot rmsV V U= +

[ ]L

rmsU orbital velocity defined as: 12 sinh( )

rmsrms r

HUkd

ω=

1[ ]LT −

C Chezy friction coefficient defined as:

0

1218log( )dCk

=

1/ 2 1[ ]L T −

and 0dhdy

is the tidal surface slope alongshore, implicitly defined by the tidal current

velocity V at a reference depth d , as follows: tidal ref



0tidal ref

dhV C ddy

= (1.11)

The value of the bottom roughness, may vary between several cm’s and several dm’s to

yield results which are comparable with field measurements. The advise value is bk

0.1bk =

Figure 6.7

6.6.2.3 Sediment transport

The sediment transport along the cross ray can be calculated by using one of the available formulae for sediment transport:CERC, Engelund Hansen, Byker, v.Rijn and Bailard for sand, and Van der Meer-Pilarczyk for shingle. The transport is in general a function of ,U , the alongshore velocity V and several coefficients. For a description of the sediment formulae, see Section

rmsH rms

6.12

Figure 6.8

Definitions:

sq sediment transport rate per unit width in a cross ray.

2[ /L T ]



sQ total sediment transport. It is the integration of sq over the cross ray.

3[ /L T ]

sV total sediment volume It is the integration of sQ over the duration of one or several wave conditions (wave scenario)

3[ ]L

nsQ normalised total sediment transport. It is sV

divided by the total duration or another normalization base.

3[ /L T ]

( )nsQ θ n

sQn

as a function of the coastangle (by calculating

sQ for various coastangles θ ).

3[ /L T ]

( )asQ θ analytical approximation of Q ( )n

s θ 3[ /L T ]

)

If a variation in the wave conditions exists along the coast due to local effects, the transport will also be a function of the alongshore coordinate : ( ,a

sx Q θ x

x

. This function represented by a number of coeffcients, is used for the coastline model.

6.6.2.4 Coastline evolution

A coastal stretch which slowly varies in alongshore direction is considered. Along this stretch the beach can be characterized by a single, invariant profile of arbitrary shape. Locally, straight and parallel depth contours are assumed. The offshore wave climate is assumed to be spatial invariant or slowly varying along the coastal stretch. Given these assumptions the alongshore sediment transport varies mainly along the coast with the change of the beach normal with respect to the offshore wave incidence. The alongshore transport gradients are assumed to be compensated by accretion or erosion of the coast. The profile characterizing the beach is assumed to more horizontally over its entire active profile height. This is known as the one-line or single line approach. We will first redifine the total sediment transport Q simply to again. Due

to the local properties of the coast (e.g. revetments, groynes)

( , )as θ ( , )sQ xθ

sQ will also be a function of

the coastline position y, so Q Q ( , , )s s x yθ= . The coastline equations reads:

0sp

Qyht x bqδδ

δ δ+ + = (1.12)

and

gyx

δθδ

= (1.13)

where:



( , , , )s sQ Q x y tθ= =the longshore sediment transport rate

[ /3m y]

]

0 ( )ph h x= =the local active profile-depth

[m]

( , )b bq q x t= =the local source or sink term

2[ /m y

x =the alongshore coordinate [m] y =the coastline position [m] θ =the coastangle [rad]

( )g tgθ θ= = /y xδ δ , the coastangle gradient

[-]

t =time [y] The boundary conditions at x=0 and x=L reads: Option 1: ( )sQ t a= ,constant value or a function of

time [ / 3 ]0

m yOption 2: /y tδ δ = , which implies: / 0sQ xδ δ = Option 3: /sQ t 0δ δ = , which implies that

remains constant. ( )sQ t Sources and sinks can be defined at any point as follows:

( )bQ t a= , constant value or a function of time [ / 3m y]

6.7 Schematizations and approximations

6.7.1 The sediment transport as function of the coastangle

If the transport sQ is calculated for a number of coast angles, covering the range of wave

angles in the wave scenario, the graph of Q ( )s θ will show positive values left of the equilibrium angle and negative values right of it. The equilibrium angle is the coast angle for which the transport is zero. The function ( )sQ θ can be approximated by the analytical function:

(1.14) 2

2( )1

rcas rQ c e θθ −=

where: r eθ θ θ= − (1.15) is relative coastangle, and



eθ the equilibrium angle. The coefficients and c are determined by the method of the least squares. 1c 2

Figure 6.9

It may occur, due to an irregular devision of the wave angles, that there are three equilibrium angles in the coastangle domain. In that case the middle one will be used. Negative values at the left of this angle and positive values at the right are neglected in the method of the least squares.

Figure 6.10

6.7.1.1 The sediment area and dynamics area

The sediment area [ ,1 ]r rCx x defines that section of the cross ray, from which the sediment

transport is supposed to be responsible for the coast line evolution. The ‘dynamic area’ is the active section of the cross ray. That means that the depth contours in that section react like the coast line itself. The sediment area should be inside the dynamic profile. Generally both sections will be the same. The 1

rx value should be chosen by the user. The first rx -point for



which yields: , for all coast angles, is called the coast point ( ) 0rsq x = r

Cx . The coast point rCx in the cross ray, coincides with the coastline position Y in the coastline model.

sQ

Figure 6.11

For the calculation of ( )θ , the coast angle θ is only varied for the depth contours in the dynamic area of the profile, the angle of the depth contours in the static area remain unchanged.

Figure 6.12, Dynamic area of profile

6.7.1.2 The by-pass transport at groynes

If we consider the sediment transport sq in the cross ray for the coast angle next to the groyne, the by-pass transport can be defined as:

(1.16) 1

rf

fr

xr

s sx

Q q d= ∫ x

where fx is the position of the front of the groyne in the cross ray.



Figure 6.13

The functions ( , )

f

rs fQ xθ are approximated by ( ). (r

f f sF x Q )θ , where ( r )f fF x is the

normalized averaged of a number of ( )fs fQ x -functions in the main part of the coast angle

domain.

Figure 6.14

For a percentage of blocking of p%, the actual transport passing the groyne is: ( , ). ( )q r r

s s fQ Q x x for known and xθ β θ= f (1.17)

where:

( ) 1 . 1 ( )100

rf

px Fβ rf fx = − −

(1.18)

6.8 Numerical solutions

6.8.1 Cross shore equations



For the numerical solution of the three differential equations for energy decay, wave setup and alongshore current, a non equidistant grid is defined in the cross ray. The user itself should take care of small stepsize ant places of strong energy decay.

Figure 6.15

The different equations are: Energy decay

: 1

1

cos cos0

g gr r fi i b

i i r r i

E Ec cDD

x x

α αω ω

ω ω−

−

− + + = −

Wave setup :

[ ]110

1 1

[ ] [ ] [ ( )] . i ixx i xx ii

i i i i

S S g hx x x x

η ηρ η −−

− −

−− 0+ + =− −

Current : 1 0

21

[ ] [ ][ |xy i xy i

tot ii i

S S dh ggd V Vx x dy C

ρ ρ−

−

−|] 0+ + =

−

This results for each grid point in 3 nonlinear equations in the unknowns , iE iη and V . In a iteratively process the equations are linearized numerically and solved, until the nonlinear equations are satisfied. At the sea boundary, ,

i

E η and V are known from the boundary conditions.

6.8.2 Coast line equations

Along the coastline model in x-direction, a staggered grid is defined. The main points are call x_points, the points in between the x-points: yx -points. At the x-points the alongshore sediment transport sQ is the product of the available analytical function Q and a

multiplication factor

( , )as θ x

( )yβ , where 0 ( )y 1β≤ ≤ at groynes and beach revetments. Scheme:


Title X0000.00

September, 2005

Option 1 ( )BsQ t a= , constant value of a function of time [ / 3m y]

1 11 2j jAt x=0 : and Q Q substituted in equation

(1.19) for k=1 At x=L : and Q Q substituted in equation

(1.20) or k=n-1 Optional 2

0yt

δδ

= , which implies: 0sQx

δδ

=

At x=0 : and Q substituted in equation (1.19)


Figure 6.16

The x point scheme : { , 1, }ix i n=

The yx -point scheme : { , 1, 1}ykx k n= −

Figure 6.17

The equation of continuity:

1

1 1 11

01 1

. i i k

k

j j jj js s bk k

i i i i

Q Q Qy yhdt x x x x

+

+ + ++

+ +

−− 0+ +− −

= (1.19)

with k=1,n-1. The coast angle relation:

1 1

1 1

1i

j jj k k

g y yk k

y yx x

θ+ +

+ −

−

−=

− (1.20)

with i=2,n-1. The boundary conditions:

θ θ+ += 1 ( )i

j Bs s t dt+ = +

1 11

j jn nθ θ+ +

−=1

1 ( )i

j Bs s t dt

+

+ = +

1 11 2j jθ θ+ +=

1

1 1i i

j js sQ

+

+ +=


for k=1 At x=L : and Q substituted in equation (1.20)

or k=n-1 Optional 3

0dtδθ

= , which implies that remains constant ( )sQ t

At x=0 : At x=L :


1 11

j jn nθ θ+ +

−=1

1 1i i

j js sQ

+

+ +=

11 1j jθ θ+ =

1j jn nθ θ+ =

6.8.2.1 Groynes

If the position of the front of the groyne is , its relative position in the cross ray is: fy (r )f C fx x y y= − − (1.21)

where Cx is the coast point of the cross ray. for a percentage of blocking of p%, the actual transport passing the groyne is:

(1.22) ( , ). ( )a

s sQ Q x yθ β=for known θ and y, where: where:

( ) 1 . 1 ( )100

rf f

py Fβ x = − − (1.23)

Figure 6.18


Figure 6.19

The problem is, how to define the coastline position y and the coastangle gradient gθ at a

groyne. There is a discontinuity in the coastline at a groyne location, so it is not possible to use an unique definition for g and gθ and y.

If the transport passes in positive direction, y and θ must be defined at the positive side of the groyne and in the reversed situation at the negative side. However, one has to choose for a direction first before the transport can be calculated. Therefor both situations are being analysed in the program. In normal circumstances only one assumption will result in a passing transport, but it may occur that both assumptions will give passing transports or neither of them will. In the first case, the substraction of both transport is applied, in the second case the transport is supposed to be zero. These two exceptional situations may occur in cases where the shape of the coastline is more or less symmetric around the groyne.

Figure 6.20

Now we will work out the algorithme to determine y and θ in the positive transport situation. There are three different phases:



1 : if c fy y> then ,c iy y cθ θ= =

2A :if cy y f< and ex fy y< then 1,ex i iy y θ θ −= =

2B and ex fy y> then ,f iy y fθ θ= =

where:

cy = the y-position at the groyne using a straight connection line between the y-position at both sides, 1ky − and . ky

cθ = the angle of that line.

exy = the y-position at the groyne using an extrapolation of the y-line at the positive side.

fy = the y-position of the front of the groyne

fθ = the angle of the line connecting 1ky − with fy

Figure 6.21

6.8.3 Revetments

At coastal revetments or at places with non-erodable material, from a certain y-position no erosion can take place, while sedimentation and the passing of transport can. To prevent erosion of the coastline and allow sedimentation and the passing of transport, the following algorithme is used.



The actual sediment transport at point “i” is defined as : ( , ). ( )

i

as s i i iQ Q x yθ β= (1.24)

where: if Q 0a

s > then 1i ky y −=

if Q 0as < then i ky y=

If we define the position of fixation as and the relative position as , and we

introduce a thin y-layer in front of if

y

i

ir iy y y= − f

fY with a thickness of δ (one or several meters), then

the multiplication factor can be defined as: if 0ry < then ( ) 0iyβ =

if ry δ> then ( ) 1iyβ =

if 0 ry δ< < then ( )iy aβ = function between 0 and 1 with derivatives zero at 0ry =

and ry δ=

Figure 6.22

With this algorithme any reduced sediment transport can be satisfied by an -position

within the ry

δ -layer. The accuracy of meeting the required fixation value fy depends on the

thickness of the δ -layer. Because the program operates with linearized equations, it will be clear that this algorithme will not allow large timesteps. The variation of y per timestep should be far less then the thickness of the δ -layer to avoid instable behaviour.

6.8.4 Numerical solution

The sediment transports 1i

jsQ + and

1

1i

jsQ

+

+ in equation (1.19) are linearized to the unknowns

and 1jy + 1jθ + of neighbouring points. Then there are n unknown 1jθ + -values in the x-

points i=1,n and n-1 unknown 1jy + - values in the yx -points k=1,n-1, and we have a set of n-1 continuity equations, n-2 internal coastangle relations and two boundary relations, making a set of 2n-1 linear equations with 2n-1 unknowns with a bandmatrix structure. Each timestep the linearization is made and the set of linear equations is solved.



6.8.4.1 The linearization

For a normal point without a groyne or a revetment we have: 1 ( )

i

j as s iQ Q θ+ = (1.25)

linearized as:

1 . .(i

i i i

asj j j 1 )

i

js s g

i g

Q dQ Qd

δ θgθ θ

δθ θ+ = + −+

1

(1.26)

For a point with a groyne or a revetment it is more complicated: 1 ( ). ( )

i

j a js s i iQ Q yθ β+ += (1.27)

linearized as:

1 1

1

| . .( ). ( )

( ). | .( )

i i i i i

ji

aj j j j js

s s x x g g ig

a j j js i i iy

Q dQ Q yd

dQ y ydy

δ θ θ θ βδθ θ

βθ

+ +=

+

= + −

−

+ (1.28)

At groyne, 1i

jgθ + and can be substituded by a linear function 1j

iy +1 1( ,

ig ky )θ− −Φ , or

1( ,

i)g kyθ

−Φ , depending on the situations as described in Section 6.8.2.1 and for a revetment

can be substituted by 1jiy + 1

1j

ky +− or 1j

ky + depending on the situation as described in Section 6.8.3

6.9 Modelling of beach line developments behind offshore breakwaters and groynes

6.9.1 Introduction

The modelling of beach line developments behind offshore breakwaters and in the lee side (diffraction zone) of perpendicular groynes can be represented in UNIBEST-CL by defining a so-called LOCAL TRANSPORT TABLE (item 5 of the Menu Definition Phase, Unibest-CL). A local transport table consists of a number of rows representing the local transport function (see Figure 6.23 ) in terms of a sequence of coefficients: x, eqα , and c , where: 1c 2

x : coastline position (increasing values)

eqα : equilibrium coast angle (angle where 0nsQ = )



1c : coefficient determining

nsdQ

dαat eqα

2c : coefficient determining higher order effects

2

2

nsd Q

dα

Figure 6.23

Several local transport tables can be active in one UNIBEST-CL run. Each table must be related to a different region of the coastline which is modelled (see Figure 6.24 ).

Figure 6.24

In the computational domain which is not covered by a local transport table the regular TSC file which is specified in the menu option: Run Parameters of UNIBEST-CL is used to determine the global transport function. The coefficients eqα and c representing the global transport function of a TSC file can 1c 2

be inspected with the program SHOWTS (see menu option Coast Transports).

6.9.2 Coefficients of local transport table

There are several possibilities to determine the coefficients of a local transport table:



6.9.2.1 Application of STRUCT program

The STRUCT program can be used to modify the global transport function. You can modify the contribution of one or more wave scenario conditions to the average longshore transport function according to the same principle which is used in the program SHOWTS (with SHOWTS you can change the transport function by changing the factor in the menu option Coast Transport). However, with STRUCT you can treat a continuous modification along a whole coastal section at one stroke (in stead of individual points as in SHOWTS). In Figure 8.3 an example is presented how such a modification may look like. The other wave conditions from the wave scenario can be treated one by one in the same way with STRUCT.

Figure 6.25

At the end of a STRUCT session the local transport coefficients for aH x-points in the coastal domain are computed and stored in a so-called Loc-file taking into account the local factors applied for the continuous modification of aH the wave conditions. The Loc-file can be copied directly to a local transport table if you prepare the input for a UNIBEST-CL run (key < CTRL-F4 > ). A prerequisite of STRUCT is that the user must have al ready some idea how the local transport function, for each wave conditions of the wave scenario is affected by the coastal structure (i.e. how the continuous modification per wave condition must be selected). A major drawback of STRUCT is that the program operates on the original (offshore) wave climate data to determine a local transport function. This implies that everywhere in the coastal area the new equilibrium angle of the local transport function will be found some-where between the minimum and maximum values of the wave directions which are present in the original wave climate. If the wave climate consists only of one wave condition the equilibrium angle will not change at all. In a situation with a tombolo or vast salient, where the local wave conditions are mainly determined by diffraction, the application of STRUCT for the determination of a local



transport table will lead to a less realistic beach line development of UNlBEST-CL. If the STRUCT program is used to derive a local transport table the user must convince himself that this is not the case.

6.9.2.2 Application of diffraction diagrams SHORE PROTECTION MANUAL 1984

To overcome the drawback of STRUCT The user can prepare its own local transport table on the basis of the wave diffraction diagrams for a semi-infinite breakwater presented in the SHORE PROTECTION MANUAL (SPM, 1984) or any Diffraction computer model. The procedure which must be applied is as follows: • Step 1: Determine local wave conditions at location of breakwater For each wave condition in the offshore wave scenario the local wave condition (wave height and direction) is determined at the location where the breakwater is found. This can be done with a standard UNIBEST-LT run in which the offshore wave climate is specified at the seaward boundary of the profile and the boundary between static and dynamic profile is chosen at the location of the breakwater (note that the breakwater itself is not modelled in this UNIBEST-LT run). Preferably, the offshore wave climate must consist of 1 wave height per direction. This wave condition results in the same time-integrated sediment transport as the whole range of wave heights from the considered direction would result in. • Step 2: Determination of local wave climate at specific output points Subsequently, the local wave conditions behind the offshore breakwater are determined with specific wave diffraction diagrams. The local wave conditions are derived in a number of output points which are located along an output line (see Figure 6.26). The distance of the output line behind the offshore breakwater has to be chosen more or less arbitrary. The basic idea is that diffraction is only important within a certain region behind the breakwater whereas at a larger distance the wave propagation is taken over again by refraction and directional wave spreading. Usually, a distance of 1 to 2 times the local wave length ( . pgh Tλ = ) is sufficing for the location of the output line. In each output point the local

wave conditions must be determined on the basis the diffraction of the incoming waves around the diffraction points Dl and D2. The number of output points along the output line depends on the accuracy which is required to schematize the local transport table. For standard UNIBEST calculations a total number of 6 to 8 output points is sufficient.



Figure 6.26, Diffraction pattern and definition of output points

In Figure 6.26 the procedure for the wave direction of 30 (deg) is shown. For this wave direction the diffraction diagrams for the wave angles of 60° (point Dl) and 120° (point D2) will be used (note that the wave angle in the diffraction diagrams is specified as the angle between the wave direction and the direction parallel to the breakwater). To apply the diffraction diagrams you must look after the scale which is used to represent the breakwater (in terms of N times wave length). The scale which is used must be in accordance with the scale of the diffraction diagrams. The diffraction coefficients and the wave directions (relative to the coast normal) in the output points for the wave direction of 30° are summarized in Figure 6.27. The remaining wave directions can be treated in the same way. In this way it is possible to determine a local wave climate for each output point. The angles of the wave diffraction diagrams will often not entirely coincide with the computed wave directions at the location of the breakwater. In this case the diffraction diagram of the nearest wave angle must be chosen. The orientation of the selected diffraction diagram must coincide with the actual wave direction. Dl D2 Output points

K (-) 4> (deg) K (-) 4> (deg)

Ol 1. 00 30 0.08 -79

O2 0.95 30 0.095 -77

O3 0.40 45 0.11 -72

O4 0.32 63 0.13 -63

O5 0.22 72 0.18 -45

O6 0.18 77 0.30 0

O7 0.15 79 0.80 30 • Step 3: UNIBEST-LT computations for the local climate



The local wave climate which is determined according to step 2 in the output points is used to carry out additional UNIBEST-LT computations. For each output point a separate UNIBEST-LT run must be performed, including the preparation of a TSC file. For each output point the program SHOWTS can be applied to derive the corresponding coefficients of the local transport function (keeping all the factors at 1.00). Note that in UNIBEST a threshold value is applied to compute the transport. This implies that for small wave heights (approx. < 0.2 m) the transport is set to zero automatically by UNIBEST-LT. The user must check that this will not have a significant influence on the outcome of the computation. • Step 4: UNIBEST-CL computation Subsequently the coefficients of the local transport function are used to prepare alocal transport table for the coastal area behind the breakwater. In this way it is possible to carry out a UNIBEST-CL run.



Figure 6.27, Diffraction diagrams SPM(1984)

6.10 Modelling cases (Based on DOS version)

In this chapter the use of the UNIBEST Coastal Software Package is demonstrated with two projects which have been carried out by DELFT HYDRAULICS. The first project refers to a coastal erosion study in Kelantan State, Malaysia where human activities in the coastal zone in combination with a physical infrastructure have caused a dramatic effect on the coastline. DELFT HYDRAULICS was commissioned to study the cause of this erosion, taking into account both the autonomous development of the coast and the impact of river training works, and to make recommendations for future coast eros ion



management of Kelantan State. A detailed description of the project and the UNIBEST computations has been described in APPENDIX A. The second project is related to a study in which the causes of erosion within Kerteh Bay, Malaysia have been investigated including an evaluation of various possible defence schemes for the area of consideration. The project is described in APPENDIX B.

6.11 Future developments of UNIBEST

The UNIBEST Coastal Software Package is constantly subjected to revision and updating in order to increase its capabilities . The following options are worked on for next releases of UNIBEST: . UNIBEST with a curvilinear baseline to improve the accuracy of the model in situations where the coastal area shows astrong curvature (spiral beaches, islands). UNIBEST for Ms-windows with powerful options in graphic presentation and easy-to-use windowing interface techniques. UNIBEST dynamic link, using UNIBEST's built-in import/export facilities with Geographical Information Systems environments to apply interactive GIS modelling techniques for handling and analysis of spatial-referenced data. Incorporation of new wave generation and propagation model (with directional wave energy representation) to derive the nearshore wave conditions. The effects of wave growth due to the action of wind, refraction and diffraction behind breakwaters are accounted for.

6.12 Longshore transport formulae

6.12.1 Bijkers’s formula

Bijker (1976) proposed a formula for bed load due to waves and currents, which is based upon the formula of Kalinske-Frijling for bed load due to currents only. For that a formulation for the increase of the bottom sheare stress by waves has been developed. Afterwards Bijker (1968) added to the bed load a distribution of the suspended load., which is based upon the Einstein-Rouse concentration vertical. (1.29) 3( / / ,b sS S S m m s including pores= + )where:

bS =bottom sediment transport

sS =suspended sediment transport

The formulation of reads: bS



250

22

.27

112

50

b

D C

uvv

bvS bD geC

µ ξ

− ∆

+ = (1.30)

in which the mean flow is prepresented by v and the wave effect by u . The sediment and bottom characteristics are:

b

50D =median (50%) grain diameter (m)

90D =90% grain diameter (m)

∆ =relative density

cr =bottom roughness ( ≈ 0.5-1.0 times ripple height (m)

sρ =sediment’s density

w =sediment’s fall velocity (m/s)

bu =orbital velocity near the bottom (m/s)

ω =wave frequency (rad/s) From these parameters the following bottom parameters are derived: C

=Chezy coefficient = 12log( )

c

dr

18

90C =90

12log( )dD

18

µ = 3/ 2

90

( )CC

wf =

0.1945.977 5.213( )b

c

ure ω

− − +

ξ

=2

wfCg

The coefficient b varies between 1 and 5 with the former advized for use outside the surfzone and the latter for use inside the surfzone. The formulation for reads: 3( / /sS m m s)

1331.83 { ln( )s b

c

dS S Ir 2I= + } (1.31)

where:

*1

1(1 )

c

z

rd

yI Ry

−=

∫ dy (1.32)



*1

2(1 )ln

c

z

rd

yI R y dy

−=

∫ y (1.33)

*

*

1

.216

(1 )

zc

zc

rdR r

d

− =

− (1.34)

**

( 0.4wzv

κκ

= = ) (1.35)

1/ 2

2*

11 ( )2

buvv gC v

ξ = +

(1.36)

General trends with the Bijker formula are:

• The transport rate is overestimated for low transport capacities. This is characteristic for a formula without a beginning of movement criterion.

• No systematic differences can be found between the data for perpendicular wave attack and those for oblique wave attack. This would seem to indicate that the choice of the resultant bed shear instead of, for instance, the average of the longshore component of the bed shear, is substantiated for the Bijker approach.

6.12.2 Formula of Engelund-Hansen

The total sediment transport in excluding porosity according to the adapted Engelund-Hansen formula is:

3 / /m m s

25 2

33 2

50

10.05 1 ( )2 ( / / ,

buvvS m m s excluding pores

g C D

ξ + =

∆) (1.37)

in which the mean flow is represented by v and the wave effect by u . b

where: v =mean velocity flow (m/s)

bu =orbital velocity (m/s)

ξ =friction factor waves

50D =median (50%) grain diameter (m)

∆ =relative density

cr =bottom roughness ( ≈ 0.5-1.0 times ripple height

C =Chezy coefficient =

12log( )c

dr

18



wf =

0.1945.977 5.213( )b

c

ure ω

− − +

ξ =

2wfCg

Engelmund and Hansen derived their formula for the total volume of sediment transport per unit time, by making the following general assumptions:

• The derivation was concentrated on the case where the bed was covered by dunes. • Sand grains are eroded from the upstream side of the dunes and deposited on the lee

side. • The migration velocity of the moving particles is assumed proportional to the shear

velocity. • A simple energy balance is made between the energy necessary to elevate the

eroded sediment over a height equal to the dune height d∆ and the work done by drag forces on the moving particles in the same time interval.

Generally it can be concluded that:

• The Engelund-Hansen formulae yield transport capcities which are higher than the measured transport rates.

• The computed transport rates overestimate the transport capacities for oblique waves attack by a bigger margin than for the data with wave attack at right angles to the main current. This means that, in any case for the Engelund-Hansen typ of equation, the use of the resultant shear stress tends to overestimate the transport rates for oblique wave attack.

6.12.3 Formula of Van Rijn

The transport formulation proposed by Van Rijn gives a prediction for the convective part of the transport and is of the shear-stress type. The total transport consists of a bottom transport and a suspended transport: (1.38) 3( / / ,b sS S S m m s excluding pores= + )

a

The bottom transport is given as: b bS au c= (1.39) where: (1.40) ( )a bottomtransport layer thickness m=The velocity in the transport layer:

*,1 301 ln( ) ( / )b

c

av urκ

= − +

c m s (1.41)

The bottom concentration:



1.5

3 3500.3*

0.015( ) ( / )aD Tca D

α= m m

( 1)

(1.42)

where: : a coefficientα = ≈ (1.43) The shear-stress velocity:

*,1( )8cu f= c v (1.44)

1/3* 50 2

gD Dν∆

= (1.45)

,

,

b cw b cr

b cr

T ,τ ττ

−= (1.46)

The effective shear-stress: , ,b cw c b c w b w,τ µ τ µ τ= + (1.47)

Efficiency factor stream:

2

90

12 12log / log3c

c

d dr D

µ

=

(1.48)

The shear-stess stream:

2,

18b c cf uτ ρ= (1.49)

The efficiency factor waves:

*

0.8wu

D= (1.50)

The shear-stress waves:

2,

14b w w bf uτ ρ= (1.51)

The orbital shear-stress: , ( )b cr s crgD50τ ρ ρ θ= − (1.52)

crθ = 1*0.24D−

*1 4D< ≤

crθ = 0.64*0.14D−

*4 1D< ≤ 0

crθ = 0.1*0.04D−

*10 20D< ≤

crθ = 0.29*0.013D *20 150D< ≤



crθ = 0.055 * 150D > u = mean flow velocity (m/s)

bu = near orbital velocity (m/s) ρ = density water ( ) 3/kg m

sρ = sediment density ( ) 3/kg m∆ = ( )s /ρ ρ ρ− The sediment and bottom characteristics are:

50D = 50% grain diameter from bottom material (m)

90D = 90% grain diameter from bottom material (m)

∆ = relative density

cr = current related bottom roughness (=0.5-1 times ripple height)

wr = wave related bottom roughness (2-3 times ripple height)

From these parameters the following bottom parameters are derived: Friction factor stream:

10 2120.24( log( ))cc

dfr

−= (1.53)

Friction factor waves:

0.2( 6.0 5.2( )

0.3b

w

ur

wf e with fω−

− + = w ≤ (1.54)

The suspended transport is given as: ( )s c wS F F v d ac= + (1.55) where: ( )d water depth m= (1.56)

and and cF Fω are correction factors for currents and waves respectively:

1.2( / ) ( / )

(1 ( / )) (1.2 )

c

c

z

c zc

a d a dF

a d z

− = − −

(1.57)

1.2( / ) ( / )

(1 ( / )) (1.2 )

w

w

z

w zw

a d a dF

a d z

− = − −

(1.58)



with: The suspension number stream:

*,

cc

wzuκ

= (1.59)

The suspension number waves:

0.8 0.1 0.1 0.7*50( ) ( ) ( ) ( )b s b

wu H uzw d v

−= D − (1.60)

where: w = fall velocity suspension material (m/s)

sH = significant wave height (m)

6.12.4 Formula of CERC

The CERC transport is defined as: 3( /cS m s)

0 0

202 sin cosc s g bS A H C φ φ= (1.61)

where:

0sH = significant wave height at deep water (m)

0gC = group velocity waves at deep water (m/s)

0 0 0*gC n C=

0φ = wave angle at deep water (deg.)

bφ =wave angle at breaker depth (deg.)

The breaker depth is defined by the relation bh 2.

bb s

h Hγ =

For γ a value of 0.4-0.6 is advised. In UNIBEST-LT a value of 0.5 is used. In UNIBEST LT ‘deep water’ is the boundary of the dynamic profile. The CERC transport is a cross-shore integrated longshore transport due to wave action. So, it is only included in the absence of currents. To compare the CERC result with the other tranports a transport per unit width ( ( / is defined over the dynamic area of the

cross shore profile. The arbitrary chosen function if proportional to .

3 /m m s)3v

For the constant A different values are assumed in literature, which is partly caused by the choice of . If for the significant wave height in deep water is applied the usual value of A=0.025, though sometimes no realistic values are then obtained. Possible reasons for the uncertainty concerning the value of A may be the inaccuracies in the data, with respect to

0H 0H



both waves and longshore sand transport, on which the model is based. Moreover the CERC-formula does not account for differences in grain-size. It is observed that the CERC-formula is valid only for relatively long and straight beaches, where the longshore differences in the breaking wave heights are small only. Moreover the fomule does not account for currents which are not generated by breaking waves, such as tidal currents. If such currents are important another formula should be used. The coefficient A is advised at 0.014-0.025.

6.12.5 Formula of Bailard

The transport vector due to the combined actions of steady current, wave orbital motion and bottom slope effect is calculated with Bailard transport model in 2 horizontal dimensions:

2 3

3 5

tan| | | |tan tan

| | tan | |

f xBx x

f s sx x

cq u u

gNc

u u ugN w w

βεφ φ

ε ε β

u = < > − < > + ∆

+ < > − < > ∆

(1.62)

2 3

3 5

tan| | | |

tan tan

| | tan | |

f yBy y

f s sy y

cq u u

gNc

u u ugN w w

βεφ φ

ε ε β

u

= < > − < > + ∆

+ < > − < > ∆

,y ]

(1.63)

where: x = two directions perpendicular to each other

,x yq q = transport 3 1[ / /m m su = instantaneous, total velocity vector near the bottom [m/s]

,x yu u =instantaneous velocity component in x and y direction, respectively

[m/s]

tan xβ = bzx

∂∂

, =bottom level, +=upwards bz

tan yβ = bzy

∂∂

∆ = relative density of sediment [-] g = acceleration of gravity [ ] 2/m sN = ratio of sediment volume to total volume, bed material. [-] tanφ = angle of internal friction (rad) w = fall velocity [m/s]

fc = friction coefficient= 12 wf



Bε = efficient factor bottom transport

sε = efficient factor suspended transport

wf =

0.1945.977 5.213( )bare

− − +

ba amplitude of horizontal orbital excursion

r 502.5D [m]

The < > indicate averaging over time. The longshore transport is defined as the component of the total transport vector in longshore direction. The terms <| |m n

iu u > , with m = 2, 3, 5 and n = 0,1 can be approximated by a Taylor series containing separate terms for the wave orbital motion and the steady current, as well as the angle between waves and currents. Two Taylor expansions are possible: one with the orbital motion small compared to the steady current and vice versa. A smooth transition from one formulation to the other is taken care of. The wave orbital motion is calculated using a high order stream function method. In order to reduce computing time the required characteristics of the orbital motion are tabulated in dimensionless form as a function of wave height and wave period, both made dimensionless with water depth and acceleration of gravity. The steady current velocity is taken at a fixed reference level of 0.20 m; it is calculated from the depth-averaged velocity using a logarithmic velocity profile with roughness of 2.5 times

. 50D The formula is based on an energetics approach, originally proposed by Bagnold for uni-directional flow. The bed-load formulation originates from a force balance between pressure and shear-stress gradients in the moving sediment layer on the one hand, and gravitational forces, on the other. The suspended load formulation is based on an assumed linear relation between the energy produced by the sediment-free stream (stream power ω ) and the power needed to keep sediment particles in suspension. Bailard (1981*) calibrates the formula with measurements of littoral transport using bε and

sε . Bailard (1982) carries out an integral verification of the formula through a comparison with measured beach erosion/sedimentation. Roelvink (1988) verified the formula in a large wave flume and De Waal (1987) provided a comparison with a set of laboratory data. According to these tests, the formula computes the transport reasonably well, expect in situations with fully developed vortex ripples.



6.12.6 Longshore transport of coarse materials

The profiles of dynamically stable structures as gravel/shingle beaches, rock beaches and sand beaches change according to the wave climate. Dynamically stable means that the net cross-shore transport is zero and the profile has reached an equilibrium profile for a certain wave condition. It is possible that during each wave material is moving up and down the slope (shingle beach). Oblique wave attack gives wave forces parallel to the alignment of the structure . These forces can cause transport of material along the structure. This phenomenon is called longshore transport and is well known for sand beaches. Shingle beaches also change due to longshore transport, although the research on this aspect has always been limited. Rock beaches and berm breakwaters can also be dynamically stable under severe wave action, which means that longshore transport might also cause problems for these types of structures. Therefore the condition of start of longshore transport is important. The Shore Protection Manual (CERC, 1984) gives the well-known CERC formula for longshore transport of sand. The longshore transport is related to the energy component of the wave action parallel to the coast and the approach is given by:

0( ) :: sin 2S x Hc β (1.64) where: S(x) =material transport rate parallel to the coast 3( /m s)H =wave height (m)

0c =wave celerity = ( / )2gT m sπ

β =angle of wave attack at the coast :: = “ proportional to” The longshore transport in this formulation is independent of grain size and is only dependent on the wave condition (wave height, period and direction). The transport for shingle beaches is determined by bed load (rolling along the bottom) and not by a combination of bed load and suspended load which is the case for sand beaches. Van Hijum and Pilarczyk (1982) have studied longshore transport on gravel or shingle beaches by random wave attack and gave a formula for longshore transport of gravel beaches. Van Hijum and Pilarczyk (1982) used data of Komar (1969) on coarse sand to extrapolate their equation to smaller materials. They concluded that the formula could be applied up to beaches. Van der Meer (1990) reanalyzed the original data and came to a more simple formula for longshore transport of gravel beaches, given by:

250 50 50

cos | | cos | |( ) 0.0012 11 sin.

s s

n p n n

H HS xgD T D D

β ββ

= −

(1.65)



The range on which this equation was established was 50

s

n

HD∆

= 12-27, i.e. fairly large

gravel in prototype. The figure below shows the final results. The equation show a dependency on the grain diameter. For small grain sizes, however, the factor 11 can be deleted and the equation can be rewritten to: 2( ) 0.0012 sin 2s opS x H cπ β= (1.66)

where:

2

pop

gTc the wavecelerity

π= = (1.67)

The latter equation is according to the CERC approach. The diameter or grain size again has disappeard.

Figure 6.28

Longshore transport of coarse materials such as shingle and small rock (no berm breakwaters).

The transition where the grain size no longer has influence can be given by 50

50s

n

HD

>∆

.

The equation according to Van der Meer (1990) indicates that incipient motion (start of transport) begins when 50cos 11s nH β > D . This is, however, not correct and gives an

underestimation of longshore transport for large diameters, say 50

50s

n

HD

<∆

. This

conclusion was laready reached by Burcharth and Frigaard (1987). It means that the

equation is not valid for 50

10s

n

HD

<∆

.



References

Bosboom, J., Aarninkhof, S.G.J., Reniers, A.J.H.M., Roelvink, J.A. and Walstra, D.J.R. (1997). UNIBEST-TC 2.0. Overview of model formulations. delft hydraulics Report H2305.42. Steetzel, H.J. (1993). Cross-shore Transport during Storm Surges WL|Delft Hydraulics (1992). UNIBEST, A software suite for simulation of sediment transport processes and related morphodynamics of beach profiles and coastline evolution. Model description and validation. delft hydraulics Report H454.14, 1992. WL|Delft Hydraulics (1999). UNIBEST-TC, A generic tool to investigate the morphodynamic behaviour of cross-shore profiles. User Manual. WL|Delft Hydraulics Report H3337, 1999. Abbott, M.B. et al. (1986). Computer modelling: a warning notice. The Dock & Harbour Authority, 66, No.777. Bailard, J.A. (1981). An energetics totalload sediment transport model for a sloping beach. J. Geophys. Res.,Vol. 86, no. Cll, pp. 10,938-10,954. Bakker and Edelman, 1965. Bakker, W. T. (1968): The dynamic of a coast with a groyne system, Proc. 11 th Coastal Eng. Conf., ASCE, pp. 492-517. Battjes, J.A. and M.J.F. Stive (1984). Calibration and verification of a dissipation model for random breaking waves, Proc. of 19th Intern. Conference on Coastal Engineering, pp. 649-660, American Society of Civil Engineers, New York. Bijker, E.W. (1967): Some considerations about scales for coastal models with movable bed. Delft Hydraulics Laboratory , Publication No. 50, Delft Bijker, E.W. (1971). Longshore transport computations. Proc. ASCE, Journalof the Waterways, Harbors and Coastal Engineering Division, WW4, November 1971. Hanson, H. and N.C. Kraus (1980): Numerical Model for Studying Shoreline Change in the Vicinity ofCoastal Structures. Department of Water Resources Engineering. Report No. 3040, University of Lund. Klopman, G. (1989): RFWAVE: Program for the computation of periodic gravity waves on a horizontal bottom using the Fourier approximation method of Rienecker and Fenton, DELFT HYDRAULICS, User manual. Le Mehauté, B. and M. Soldate (1977). Mathematical modelling of shoreline evolution, MR 77-10, U.S. Army Corps of Engineers, CERC, 56 pp. Pelnard-Considère, R., 1956: Essai de théorie de I'évolution des fortlles de rivages en plages de sable et de galets. IVem Journées de I'Hydraulique Question lIl, Raport 1 (1956) 74-1, 74-10. Perlin, M. (1979) Predicting beach planfortlls in the vicinity of structures, Proc. Coastal Structures 79, ASCE, pp. 792-808.



Rea, C.C. and P.D. Komar (1975). Computer Simulation of a Hooked Beach Shoreline Configuration. Journ.of Sed. Petrology, Vol. 45, No. 4, p. 886-872. Rienecker, M.M. and J.D. Fenton (1981). A Fourier approximation method of steady water waves. J. Fluid Mech., Vol. 104, pp. 119-137. Roelvink, J.A. and M.J.F. Stive (1989). Bar-generating cross-shore flow mechanisms on a beach. J. Geophys.Res., Vol. 94, no. C4, pp. 4785-4800. Rijn, L. C. van (1989). Handbook sediment transport by currents and waves; Report H461, DELFT HYDRAULICS. Stive, M.J .F. and J .A. Battjes (1984). A model for offshore sediment transport. Proc. of19th Intern. Conference on Coastal Engineering, pp. 1420-1436, American Society of Civil Engineers, New York. Stive, M.J.F.(1986). A model for cross-shore sediment transport. Proc. of 20th Intern. Conference on Coastal Engineering, pp. 1550-1564, American Society of Civil Engineers, New York. Stive, M.J.F. and H.J. de Vriend (1987). Quasi-3D current modelling : wave-induced secondary current. ASCE Specialty conf. "Coastal Hydrodynamics", Delaware. Stive, M.J.F. and H.G. wind (1986). Cross-shore mean flow in the surf zone. Coastal Eng., 10, pp. 325-340. Thornton, E.Z. and Guza, R.T., Surfzone currents and random waves, field data and models, J. of Physical Oceanography 16, p.1165-1178, 1986.



A APPENDIX A

WL | Delft Hydraulics A – 1


















WL | Delft Hydraulics A – 1 0




























































B APPENDIX B

WL | Delft Hydraulics B – 1


















WL | Delft Hydraulics B – 1 0



































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