The Bacton Sandscaping Scheme was completed in August 2019 and is one of the first “mega-nourishments” designed to work with natural processes outside of the Netherlands. 1.8M cubic metres of sand was placed on the beach in North Norfolk, designed to provide protection to the Bacton Gas Terminal against cliff erosion whilst, over its estimated lifetime of 15-20 years, supplying the beaches at the downdrift villages of Bacton and Walcott with sediment to prolong the life of the local sea defences, creating time to plan for the transition of these communities away from coast flood and erosion risk. The consent for this scheme required an extensive monitoring programme to routinely assess the scheme’s performance. Part-funded by the Netherlands Enterprise Agency’s (RVO) Partners for Water grant, Haskoning, in close collaboration with NNDC and the Bacton Terminal companies, developed a Digital Twin of the beach at Bacton to automate this analysis.
Triggers for intervention
An important part of the monitoring plan of the scheme is its performance related to the reduction of the risk of erosion to the Bacton Gas Terminal. The cross-shore profile of the scheme was designed such that it would protect the soft cliffs sufficiently from wave impact to prevent erosion during a 1:10,000yr storm (the “minimum protection profile”). In order to last its lifetime, the scheme included a sacrificial buffer that will erode over time. This was designed to feed the villages’ beaches downdrift, generating benefits there. By the time the minimum protection profile is reached, remedial action should have been taken.
To enable effective decision-making on when action should be taken to remediate an increase in risk above the desired standards, a system of triggers for intervention was introduced, consisting of an “intervention trigger” and a “decision trigger”. The intervention trigger indicates the point at which mitigation measures should be in place, in this case, when the beach profile has eroded to the point at which the cliff is likely to erode in a 1:10,000-year event*. The decision trigger is reached earlier and indicates when action should be taken to implement mitigation measures, so that these are in place before the intervention trigger is reached. At Bacton, this relates to the time needed to design, consent and construct mitigation measures, multiplied by the expected erosion of the sacrificial buffer over that time period.
At the villages of Bacton and Walcott, triggers have been set as well. These are based on the lowering of the beach and the depth of the sheet pile wall toe, and the associated stability of the sea defence. The action following these triggers, however, is not related to remedial measures but adaptation of the community to the changing coastline: in line with the Shoreline Management Plan, it would not be affordable or sustainable to replace the defences after they fail.
Using data collected on a 6-monthly basis by the Anglian Coastal Monitoring programme, these triggers can be regularly monitored.
DIVE RIGHT IN
Sign up to our newsletter
Digital Twin
As part of the design of the scheme, simulations of coastal change were made to estimate when these triggers are expected to be reached. As part of the monitoring programme that was agreed for the consent for the scheme, these predictions will be updated periodically, utilising the latest available data to recalibrate the coastal models. This would, however, still be a largely manual process, carried out every 3 years.
The Digital Twin that Haskoning developed of the beach at Bacton and Walcott aims to increase this assessment frequency to “real time”. A Digital Twin is a virtual mirror of a real-life asset and can be used, in addition to capturing its current status, to test future scenarios before implementing any changes in how the asset is being managed.
The Bacton Digital Beach Twin consists of a 3D model of the beach, based on and updated with the data from the Anglian Coastal Monitoring programme. All historical 3D models can be viewed and queried by the user as topographic maps and as beach transects, and can be compared to each other. Where the Digital Twin goes beyond generic data viewer capabilities is the automated comparison of the monitoring data against the triggers, allowing the user to assess in an instant whether triggers are close to being reached. Moreover, the Digital Twin integrates predictions of when those triggers are expected to be reached based on the recalibrated coastal model.
Collaborative design
NNDC and the Bacton Terminal Companies were closely involved in the design of the Digital Twin. The functionalities that were included, and how various parameters were visualised, were driven by the users to optimise the Digital Twin for their use case. Part of that use case is having an up-to-date overview of how the beach is developing to support day-to-day management of the coastline, but perhaps more important is the information that the Digital Twin provides for the long-term management of the coast. The predictions of when triggers are expected to be reached are used to drive investment decisions at the Bacton Gas Terminal and set the timeline for adaptation at the downdrift villages. The Digital Twin also provides NNDC with crucial information to engage with the local communities. For example, soon after the dredging campaign was finished, the scheme was hit by a number of storms. Although it looked like a lot of sand had disappeared from the beach, causing concern among residents, through the information provided by the Digital Twin, coastal managers could reassure the communities that the sand was still present in the system and doing its work to prevent overtopping and flooding. In a nutshell, the Digital Twin translates raw data into actionable insights that help manage the coastline at Bacton and Walcott in a more sustainable way.
* Borsje, R., Flikweert, J., Price, C. and Everington, N. BACTON SANDSCAPING: QUANTIFIED BENEFITS 4 YEARS AFTER CONSTRUCTION. (2025). Coastal Engineering Proceedings, 38, papers.33. https://doi.org/10.9753/icce.v38.papers.33
[This article appeared in Issue 11 of Flood Industry magazine, March/April 2026. You can view it here.]