Sandscaping: British Translate Dutch ‘Sand Engine’ Coastal Restoration Method

Coastal erosion on the East Coast of the United Kingdom (U.K.) is a well-documented, long-term phenomenon. The normal coastal protection systems of beach replenishment, groynes and seawalls have long been recognized as being insufficient, but the issue at hand was: what could be done instead? Heavy storms in 2007, followed by more storms in 2013, increased the erosion on the already depleted North Sea coastline in the area of Norfolk. At Bacton, where an important gas terminal is located, plus a series of smaller villages along the shore, beaches, cliffs and seawalls were left exposed.

According to Jaap Flikweert, flood resilience leading professional at Royal HaskoningDHV, a Dutchman living for quite some time in England, “Without intervention, the sand on the coastline will certainly in the long run recede, endangering coastal towns. The sand has been slowly ebbing away for a very long time. The moment was ripe to explore some innovative systems to remedy England’s worsening coastal erosion.” 

Twenty sites were identified where improvements could be made and in a confluence of events, Bacton emerged as the first candidate location. “The Bacton Gas Terminal is an important energy asset and a critical infrastructure, which receives up to one-third of the U.K.’s gas supplies. The groynes, revetments and seawalls built in the 1950s and 1960s to protect the villages, the terminal, the pipelines and the shoreline have reached the end of their life cycle and are at increased risk as a result of falling beach levels. One traditional solution would be rock or concrete to protect cliffs and pipelines, but that would cause more erosion. Another traditional solution would be regular beach nourishment, but that wouldn’t work because it is so costly. Mobilization of vessels and pipelines is expensive, can only be justified for a large volume of nourishment,” Flikweert said. “A comprehensive, innovative solution was needed.”

A possible answer to the impending threat to the terminal and villages came when British maritime experts looked across the English Channel to the Dutch and saw the success of the so-called “Sand Engine” project south of The Hague. The Sand Engine, an outgrowth of the Building with Nature movement, represents an experimental, innovative “soft” solution, as opposed to hard seawalls and groynes. In 2011, dredges placed 21.5 million cubic meters (more than 26.1 million cubic yards) of sand in the coastal waters of the Netherlands and waited for the waves, wind and currents to slowly spread the sand. The question was would this naturally replenish the beaches and restore the coastal equilibrium. Now, seven years later, the answer is yes. The system is proving to be successful and sustainable and can be a financially viable solution.

Financial Viability

Financial viability is crucial in planning and implementing coastal protection. With parts of the U.K. coastline being owned by The Crown Estate, the appropriate British authorities and private industry acknowledged the seriousness of the problem, and they were willing to try to translate the Dutch Sand Engine to a British coastal situation.

Studies were undertaken by several partners including the National Oceanography Centre (NOC), the British Geological Survey, The Crown Estate, the Cardigan Bay Coastal Group, Royal Haskoning DHV, the Environment Agency, Natural England and National Grid. Some of this was funded by the Natural Environment Research Council (NERC) through a program to support knowledge exchange between research and the commercial practices.

The British are calling it “Sandscaping,” a play on the word landscaping. Royal HaskoningDHV, which had an important role in developing the design of the original Dutch Sand Engine concept, is uniquely qualified to examine the U.K. bathymetry but also institutional settings, and conduct the necessary Environmental Impact Assessments (EIA). The baseline design, which is being fine-tuned now, is to dredge and place 1.5 million cubic meters (2.5 million cubic yards) of sand along a stretch of coast 5 kilometers (about 3 miles) long, which will protect the Bacton Gas Terminal, operated by Shell and Perenco, as well as nearby villages. That volume of sand is approximately equal to the volume of a typical large soccer stadium.

Sand will be mined from existing licensed dredging areas. The idea behind the plan is that wider beaches can reduce the impact of waves on coastal defenses by causing them to break further offshore, as well as offer additional protection from erosion. The terminal, where the cliffs are totally covered by sand, will not be reached by waves at all. The villages will have a higher, wider beach that reduces the exposure of the seawall to waves. Models indicate that this natural defense should stay in place for 15 to 20 years.

Dredging Contractors Involvement

Flikweert adds, “Working with dredging contractors early on was an important part of developing the design. The knowledge that the contractors have about sand mining and methods of sand placement was an important contribution. We issued an open invitation to any interested contractors to think along with us. They shared insights that only they have – that were unique and useful.”

The procurement process has begun, and the goal is to start working this summer. The period from May to October is the window of opportunity before the autumn storms with possible devastating results set in. But a lot depends on how quickly the environmental and other licensing processes proceed.

Funding for the project is a public-private venture of Bacton Gas Terminal and the North Norfolk District Council (NNDC), where NNDC is the operator. The project is a great example of positive collaboration between organizations with very different roles and cultures to achieve shared objectives.

Flikweert explains, “In the Sandscaping initiative we are working with our British partners to translate the Dutch Sand Engine to the very different context of the U.K. The bathymetry of the U.K. is different than that of the Dutch waters. Therefore, for instance, instead of placing large quantities of sand at sea, we will use pipelines and pumps to place the sand. But the aim is the same – to use the natural energy of the sea to distribute the sand, which can make sandy solutions affordable. It enhances the natural coastline without leaving permanent marks, and can be adapted and extended easily if needed in the future. Sandscaping also means a design for multiple functions and stakeholders to generate benefits and funding.”

Public consultation has taken place and Royal HaskoningDHV’s work on the Environmental Impact Assessment (EIA) is underway. The company has also prepared the business case to secure national government funding, as well as develop the operations, maintenance and monitoring plan for the scheme with placement scheduled to take place during summer 2018 or 2019. The University of Liverpool and other academic institutes have worked closely with The Crown Estate in developing their Sandscaping approach, which offers additional benefits in terms of habitat creation and environments that may provide a catalyst for economic development.

This is an important step to increase the resilience of the English coastline against storms and sea-level rise. Flikweert said, “The Bacton project is the first time the Sand Engine concept will be applied outside the Netherlands, and it is certainly not a copy-paste project. But it is a solution that merits further observation and could perhaps be adapted and applied in other areas of the UK and even coastal areas in the United States.”