XBeach-G is a branch of the main XBeach development that is being developed to simulate storm impacts on gravel beaches. The development of XBeach-G is taking place as a joint collaboration between Plymouth University and Deltares, as part of the EPSRC-funded NUPSIG-project.

XBeach-G uses the one-layer, depth-averaged, non-hydrostatic extension to the XBeach model (nonh=1), which is similar to the SWASH model (Zijlema et al., 2011) to solve wave-by-wave flow and surface elevation variations due to short waves in intermediate and shallow water depths. This is particularly important for application on gravel beaches, where due to steep slopes swash motion is mainly at incident wave frequencies, and infragravity wave motion, which dominates the inner surf and swash zone on sandy beaches during storms, is of secondary importance. To correctly account for upper swash infiltration losses and exfiltration effects on lower swash hydrodynamics on gravel beaches, XBeach-G computes groundwater dynamics and the exchange between groundwater and surface water using the XBeach groundwater model (gwflow=1). Again, interaction between swash flows and the beach groundwater table are considered particularly important on gravel beaches due to the relatively large hydraulic conductivity of the sediment, while on sandy beaches this process is of significantly less importance. Finally, gravel sediment transport processes have been included in XBeach-G to simulate the morphodynamics of gravel beaches during storms. These transport processes are currently under further development and validation.

Details of the XBeach-G model equations and validation can be found in the following publications (pending update):

  • NEW. McCall, R.T., 2015. Process-based modelling of storm impacts on gravel coasts. Plymouth University, PhD thesis. Download at Plymouth University repository. Download electronic book version.
  • McCall, R.T., Masselink, G., Poate, T.G., Roelvink, J.A., Almeida, L.P., 2015. Modelling the morphodynamics of gravel beaches during storms with XBeach-G. Coastal Engineering. Full paper (open access)
  • Masselink, G., McCall, R.T., Poate, T., Van Geer, P., 2014. Modelling storm response on gravel beaches using XBeach-G. Proceedings of the ICE - Maritime Engineering. Full paper (open access).
  • McCall, R.T., Masselink, G., Poate, T., Roelvink, J.A.,  Almeida, L.P., Davidson, M., Russel, P.E., 2014. Modelling storm hydrodynamics on gravel beaches with XBeach-G, Coastal Engineering. Author's Accepted Manuscript. Full paper (open access).
  • McCall, R.T., Masselink, G., Poate, T., Bradbury, A., Russell, P., Davidson, M., 2013. Predicting overwash on gravel barriers. Proceedings 12th International Coastal Symposium, Journal of Coastal Research, Special Issue No. 65. Plymouth, United Kingdom. ISSN 0749-0208. Full paper (open access).
  • McCall, R., Masselink, G., Roelvink, D., Russell, P., Davidson, M., Poate, T., 2012. Modelling overwash and infiltration on gravel barriers. International Conference of Coastal Engineering, Santander. doi:10.9753/icce.v33.currents.34. Full paper (open access).

Model limitations

XBeach-G is currently under development, therefore the results of model simuations should be considered with due care. In particular, the following aspects are important to note

  • The XBeach-G model has not been fully developed and validated for morphodynamic updating. User calibration of the morphodynamic parameters will be required if morphodynamic computations are carried out.
  • The XBeach-G model has been validated for hydrodynamics and groundwater dynamics in 1D situations only. Situations with longshore non-uniform coasts, or with waves with large angles of incidence may not be modelled appropriately in a 1D model. For this reason, the XBeach-G model GUI only supports the set-up and analysis of 1D XBeach-G models.


The XBeach-G model and model GUI are available for download here. The original source code for the XBeach-G model can be found in the XBeach SVN directory, under tags/XBeach-G.


Screenshot of GUI input windows


Screenshot of GUI output windows