\chapter{Introduction}

This document reports on the hydrodynamic and morphodynamic accuracy of the XBeach model that is to be applied in the BOI Zandige Waterkeringen project. This document is part of the XBeach testbed (alongside the trunk default skillbed) and is generated automatically any time the model code is updated. The XBeach testbed is an environment, which automatically executes simulations, analyses simulations and generates reports with the results. The XBeach source code is hosted on a SVN repository, which is publicly available (open source). A new commit to this repository starts the trigger to create this report. The date and revision number of the XBeach model code used in this report is given on the cover of this skillbed report. 

The function of this skillbed report is twofold. The testbed cases show the performance of the BOI XBeach model for multiple applications in terms of quantitative statistical scores and visualizations. Apart from the performance, this report can also be used to track the code development and verify the impact of a commit in the source code.

The accuracy of the XBeach model is determined by comparison to laboratory experiments and field measurements. The BOI parameter settings presented in \cite{Deltares2021_par} and given below in Table 1.1 are applied. This report provides quantitative insight into the ability of the model skill with a uniform set of model parameters. In \autoref{tab:BOI_tests} it is indicated which tests are applied to calibrate the parameters. The derived BOI settings are applied in all the described validation cases to show the performance of the BOI XBeach model. Note that these parameters are derived for the Dutch coast and, therefore, do not always correspond to the XBeach default parameters. 

In this report the results are not discussed since the results can change between different versions of XBeach.


The validation cases and source code are publicly available in the OSS XBeach repository: \\

\href{https://svn.oss.deltares.nl/repos/xbeach/skillbed}{https://svn.oss.deltares.nl/repos/xbeach}.
Moreover, after each commit the skillbed reports are published on the XBeach website:\\

\href{https://oss.deltares.nl/web/xbeach/}{https://oss.deltares.nl/web/xbeach/}.

\section{BOI settings}
The BOI settings are a set of hydrodynamic and morphodynamic parameters that have been derived using laboratory and a limited number of field datasets. The Boers and GLOBEX experiments were applied in the optimization of the hydrodynamic parameters, and the morphodynamic parameters were derived from experiments and nine field measurement cross-shore profiles. Table \ref{tab:BOI_parameters} shows the BOI parameters of XBeach.  

The XBeach defaults are applied for the other parameters, except for case specific parameters, such as the boundary conditions and grid related parameters. Note that the reduction of the short-wave group signal (wbcEvarreduce) is only applied in the field validation since we this reduction is only required when modelling 2D cases with a 1D model.

\begin{table}[h]  
\centering
	\begin{tabular}{  p{3cm}  p{2cm} p{2cm}  }\hline \hline
		Keyword & BOI \newline parameters & XBeachX default parameters \\ \hline \hline
		bedfriction & Manning & Chezy  \\ \hline
		bedfriccoef & 0.02 & 55 \\ \hline
		form & VanThiel VanRijn & VanThiel VanRijn \\ \hline
		waveform & vanthiel & vanthiel \\ \hline
		facSk & 0.15 & 0.1 \\  \hline
		facAs & 0.20 & 0.1 \\  \hline
		wetslp & 0.15 & 0.3\\  \hline
		beta & 0.08 & 0.1 \\  \hline
		break & roelvink daly &roelvink2 \\ \hline
		gamma & 0.46 & 0.55 \\  \hline
		gamma2 & 0.34 & 0.3 \\  \hline
		alpha & 1.38 & 1.0 \\  \hline
		wbcEvarreduce (only for field validation of 2D cases with a 1D model) & 0.3& - \\  \hline
		alfaD50  & 0.4& - \\  \hline
	\end{tabular}
\caption[Overview of the BOI parameters and XBeachX default parameters]{Overview of the BOI parameters and XBeachX default parameters. See the online manual for the explanation of the parameters (\href{https://xbeach.readthedocs.io/en/latest/user_manual.html}{https://xbeach.readthedocs.io/en/latest/user\_manual.html}).}
\label{tab:BOI_parameters}
\end{table}  

\section{Reader's guide}
The hydrodynamic validation is shown in \autoref{sec:Hydrodynamics} and the the morphodynamic validation in \autoref{sec:morphodynamic}. The field validation of both hydrodynamics and morphodynamics is shown in \autoref{sec:field_validation}. An explanation of the model performace statistics is shown in \autoref{app:ModelPerformanceStatistics}. Furthermore, in \autoref{app:Detailed_analysis} a comparison of detailed properties is shown for selected cases.


\begin{table}[h]  
	\centering
	\begin{tabular}{  p{4cm}  p{3cm} p{3cm}  }\hline \hline
		Test & Type & Applied in the calibration \\ \hline \hline
		Long wave propagation & Hydrodynamics & no \\ \hline
		1D wave runup & Hydrodynamics & no \\ \hline
		High- and low-frequency wave transformation over a barred beach & Hydrodynamics & yes \\ \hline
		High- and low-frequency wave transformation over a gentle sloping beach & Hydrodynamics & yes \\ \hline
		H4357: Delta Flume 2006 & Morphodynamics & yes \\  \hline
		M1797: Delta Flume 1981 & Morphodynamics & yes \\  \hline
		M1263 III: Delta Flume 1984 & Morphodynamics & yes \\  \hline
		LIP11D: Delta Flume 1994 & Morphodynamics & yes \\  \hline
		LIP11D: Delta Flume 1994 & Morphodynamics & yes \\  \hline
		H4731: Delta flume 1998 & Morphodynamics & yes \\  \hline
		Grosse Wellen Kanal 1998 & Morphodynamics & no \\  \hline
		Schiermonnikoog & Hydrodynamics & no \\  \hline
		Saint-Trojan & Hydrodynamics & no \\  \hline
		Egmond & Morphodynamics and  Hydrodynamics& no \\  \hline
		Vlaanderen & Morphodynamics & partially (three profiles) \\  \hline
		Vedersoe & Morphodynamics & no \\  \hline
		Fire-Island & Morphodynamics & partially (three profiles) \\  \hline
		Langeoog & Morphodynamics & partially (two profiles) \\  \hline
		Holland 1976 & Morphodynamics & partially (three profiles) \\  \hline
		Holland 1953 & Morphodynamics & no \\  \hline
	\end{tabular}
	\caption{Overview of the tests in this report.}
	\label{tab:BOI_tests}
\end{table}  