A so-called ‘sand motor’ (or sand engine) will protect part of the UK coastline against coastal erosion as from 2018. It is in fact a big artificial sand bank, situated just off the coast of Norfolk. The waves and currents will gradually spread the sand naturally along a large coastal area. The Dutch ‘sand motor’ concept has become an economically viable export product.
Dutch engineering and project management consultancy agency Royal HaskoningDHV (RHDHV) has initiated the first international ‘sand motor’ as a means to stop or prevent cliff erosion. That is good news for Shell’s Bacton Gas Terminal, and surrounding villages. The consultancy agency has also been involved in the Dutch ‘sand motor’ project, and will use the knowledge acquired there in the UK. RHDHV is writing an environmental impact report, a business case to obtain government funding, and a management plan. Furthermore the agency has submitted permit applications. A contractor has not been selected yet. The work should start next year.
Project director Jaap Flikweert (RHDHV): “The Bacton Gas Terminal has hired us for advice on how to protect the terminal and pipelines against cliff and beach erosion. Using concrete and stone could cause damage to the adjacent villages of Bacton and Walcott. In the sixties, a huge concrete wall was built behind the beaches to protect the villages against erosion and overtopping waves. Since then the beach has lost three meters of sand to the sea, which has made the wall unstable.”
“About 250 families will lose their homes in due time, and will not be compensated”, Mr. Flikweert says. “A solution for the terminal alone would just accelerate the erosion, therefore we are happy to have found a solution for the whole area by introducing the ‘sand motor’, which consists of 1.5 million cubic metres of sand spread out over a 5K coastal strip. This should robustly protect the Terminal, and delay erosion near the villages at least for a couple of decades. People can stay in their homes longer and, and will be given more time to prepare for the ultimately inevitable erosion.”
By involving the local communities it has become a public-private partnership, in cooperation with the North Norfolk District Council. The part of the project aimed at protecting the villagers will be publicly financed, supervised by the Council. Mr. Flikweert: “I am quite sure the permits will be allocated soon, and the business case only needs approval from the Environment Agency, which is responsible for the distribution of the national budget for coastal management.”
The ‘sand motor’ near the town of Kijkduin in the Netherlands, added to the Dutch coast in 2011, is much bigger, and consists of 21.5 million cubic metres of sand. According to Mr. Flikweert it’s not a copy-past project. “The Dutch ‘sand motor’ primarily has been a learning project, here we had to find the best and most cost-effective solution. This ‘sand motor’ is not only smaller, and closer to the coast, it will only last for ten to fifteen years, compared to forty years in Kijkduin.” After that the project will be evaluated, and possibly adapted to new standards or insights.
Dutch experiences will be taken into account when analysing the British variant. “Among others, the Technical University Delft has developed models to calculate the present developments within the Nature Coast research program. They show that the Dutch ‘sand motor’ is moving slower than expecting. We also know more about wind erosion, which is important to us.” ≈
Source: Hilde de Laat, Technisch Weekblad