Sand Engine – Onrustgeul

Operation and Maintenance

Previous analysis of the hydrodynamics and sediment transport around the Onrust area suggested that the Onrust channel is forced open by a substantial tidal current in the channel.

In the conceptual design of the sand engine it was proposed to restrict the tidal flow in the channel by squeezing the western and eastern entrance by means of an underwater nourishment. Numerical modelling of this design suggests that under certain conditions this would lead to gradual sedimentation in the Onrust channel and a migration of the Onrust shoal towards land.

EDD: The conceptual design of the sand engine in the Onrust channel was produced by an integrated design team, which was composed of various disciplines (morphology, ecology, engineering, coastal management) and stakeholders (government, commercial, science). The boundary conditions for design were set up to reduce societal, financial and environmental cost and to provide a realistic sustainable alternative to current practice.