Impact case study database

In the IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (2019) scientists concluded that extreme coastal flooding, previously expected only once every 100 years, could become annual events by 2050. Further analysis for the UK has shown that large swathes of Norfolk and the East Coast are at significant risk, especially when rising sea levels combine with rough seas and high tides. Urgent innovation in the engineering of coastal defences is vital to protect coastal communities most at risk – or at least buy time before large-scale evacuation is inevitable.

Changing commercial coastal engineering design practice and cost savings

A former Manchester Metropolitan PhD student promoted the use of the AMAZON shallow water code (see reference [1]) in Dutch engineering firm Royal HaskoningDHV (RHDHV) [A]. According to the company’s Technical Director, Maritime and Aviation, RHDHV has now used AMAZON in approximately 40 coastal defence and infrastructure projects (20 since 2013), including some flagship and award-winning innovations that are now protecting UK communities and critical national infrastructure against flooding and erosion due to rising sea levels and storm surges caused by climate change. The code enables complex modelling that is not possible or is too expensive using current gold standard CFD or physical flume experiments. Use of AMAZON saves approximately GBP50,000 for physical modelling and GBP15,000 for off-the-shelf CFD per project (up to GBP1,300,000 total savings across 20 projects since 2013) [A].

An award winning, UK first: the Bacton Sandscaping project

The firm used AMAZON simulations to inform the design of a UK first: the GBP20,000,000 Bacton Sandscaping project in North Norfolk [A]. After a 1-in-100 year storm surge in December 2013, the land between the Bacton gas terminal and the sea was severely eroded, leaving just 15 metres between it and the sea [B]. The terminal is considered to be the UK’s most important energy hub; it processes one-third of the country’s natural gas supplies and is the terminus of the UK’s only gas supply lines from continental Europe. As such, it is designated to be a critical national infrastructure. The increasing risk of storm surges and rising sea levels were a threat to hundreds of homes in the nearby villages of Bacton and Walcott being lost to the sea [B].

RHDHV proposed a ‘sand engine’ to replenish the beach and roll it back to how it looked 30 years ago. AMAZON simulations determined the required beach recharge crest level to ensure that the designed beach profile would withstand erosion by maritime storms [A]. Construction was completed in August 2019, after 1,800,000m³ sand (half the volume of Wembley Stadium) had been pumped and ‘sandscaped’ along a 6km stretch of the coast. At its highest level, the new beach and dune stands 7m above previous levels and extends as much as 250m out to sea [B]. It is specified to protect against a 1-in-10,000 year storm. The significance of the project was highlighted by the RHDHV project manager who told the BBC “The problem is so big and so unsolvable that it needs something radical like this” [C].

The completed work now provides 400 homes (2,000 residents) and the gas terminal with 15-20 years protection against erosion and flooding. Following high, stormy seas in the autumn of 2019, a council spokesperson said that the sandscaping had protected homes in the area, stating, “Had the beach nourishment scheme not been undertaken, it is likely that high tides would have overtopped the sea wall, and homes and businesses along the stretch from Walcott to Bacton would have been under a very real flood risk” [B]. One property developer has already submitted a planning application for new-build homes, stating that the sandscaping work had pushed back the 100-year erosion line by 25 years [D].

The project delivers calculated total economic benefits of approximately GBP33,000,000 for the two villages and nearby roads at risk [E]. The project’s significance to UK energy security is evident in remarks from one energy analyst that “any disruption at the Bacton terminal would have huge ramifications. On the wholesale market, price increase would be astronomical. The energy security of the UK would be threatened” [B].

Since completion, the project has won or received commendations in five regional and national awards, including the Institute of Environmental Management and Assessment (IEMA) Sustainability Impact Awards 2020, New Civil Engineer 100 Awards 2019 and Flood and Coast Awards 2020 [A]. This cross-sectoral recognition is an indicator of the significance of the project and its innovation for UK coastal engineering and climate resilience management.

The Bacton project has been so significant and successful that RHDHV is now working with the Environment Agency, Crown Estates and local authorities, and is using AMAZON as part of investigations on the potential for sandscaping to protect 20 additional sites in the UK, including the Mount’s Bay Marine Conservation Zone in Cornwall [A,F].

Flood protection for Littlehaven: attracting tourists and keeping business open

AMAZON was also used during the design of the new Littlehaven promenade and sea wall to study wave overtopping and flood risk to the town during high seas and storms. Damage to the sea wall was causing frequent flooding along the front, leading to closure and loss of income for local amenities. Proposed seawall designs could not be represented in EurOtop, the industry ‘standard’ overtopping calculation tool by the Environment Agency, and it was too costly to use full CFD or physical modelling. The AMAZON shallow water solver was, again, the suitable and affordable solution [A].

Also known as the ‘Flood-tastic Wonderwall’, the GBP5,000,000 project replaced a more traditional ‘vertical’ flood wall with a softer, more aesthetically appealing coastal defence system. The AMAZON simulations helped with the innovative design, and modelled the impact of retreating the seawall by 50m to make more use of natural beach [G].The project won four national awards in 2014 and 2015, including one from the Royal Institution of Chartered Surveyors and the ‘Design for a Medium Scale Development’ and ‘Climate Change Adaptation’ categories in the Landscape Institute Awards 2015 [G].

The significance of the wall to Littlehaven was confirmed during the December 2013 North Sea storm surge, two months before the project was actually completed, when sea levels rose a record-breaking 4m (a 1-in-450 year event). Waves reached only halfway up the new wall with some breaking water and spray in the top half [G,H]. Responses to FOI requests confirm that no flooding has occurred since completion of the wall in 2014, including during the October 2019 storms and high tides. The benefits appraisal of the project calculates the net present value benefit of approximately GBP29,000,000 (compared with “do nothing”) [H].

A key legacy of the project will be to reinvigorate and grow the town’s attraction as a seaside resort. Tourism contributes GBP331,000,000 to the local economy and supports over 3,000 jobs in South Tyneside “so any activity to ensure its position as a popular destination, such as the Littlehaven Promenade project, is very important” (South Tyneside Council) [H]. The promenade has become a visitor attraction and is now accessible all year round, extending the tourist season and the duration of visits to the town (with a benefit to local businesses). Visitor numbers to the borough have risen from 5,511,000 visitors in 2012 to approximately 6,592,000 visitors in 2018 (latest figures) [H].

Design of the world’s largest wave flume

The Tianjin Research Institute for Water Transport Engineering, China, used the AMAZON code to study the piston wave-making power during design of the world’s largest wave flume facility; calculations were not possible using published literature. The flume was constructed between 2010 and 2014 at a cost of RMB180,000,000 (01-2014). It is the world’s most powerful wave flume and can reproduce 16m high waves and 10m high tsunamis at various scales.

Since opening, the flume has produced over 1,000 hours of experimental data in 18 live projects, including experimental studies of scouring around the piles of the Hong Kong-Zhuhai-Macao Bridge, the world’s longest sea-crossing structure. During construction of the bridge, concerns about scour around supporting piles emerged as the effect was not as previously predicted. Thanks to the piston, large-scale experiments helped to minimise scale effects; findings improved the prediction of scour processes and hence, evidence-based safety measures to protect the supporting piles throughout the bridge’s 120-year design life [I].

Supporting uptake of advanced CFD and wave modelling in industry

Under its ‘Software as an Infrastructure’ initiative, in 2015, EPSRC awarded a consortium, including Manchester Metropolitan, with funding to develop a national numerical wave tank community to drive forward adoption of advanced numerical modelling, CFD coding and high-resolution simulation methodologies, such as those pioneered at Manchester Metropolitan. The Collaborative Computational Project in Wave Structure Interaction (CCP-WSI) consortium (see Section 3) has built critical mass and delivered a return on EPSRC’s sustained research investment through upskilling and transfer to industry. Knowledge, skills and expertise have been shared through activities including cross-sectoral road-mapping, training and hackathons [J]. Since its launch, the community has grown to 169 members (from academia and industry) collectively producing 510 commits to the code repository [J]. Collaboration across the community completed development of wsiFoam, an open source numerical modelling tool based on OPENFOAM, first developed by Manchester Metropolitan (see EP/K037889/1, Section 3) [J]. The significance of CCP-WSI’s academia-industry support and training ecosystem is evidenced by its successful expansion and the award in 2020 by EPSRC of an additional GBP312,512 funding for a second 5-year period (2020-2025) “to build on impacts” (Grant ref: EP/T026782/1) [J]. The expanded consortium includes partners from across Europe, Australia, Japan, India, Hong Kong and China. Nine industrial partners include multinationals like Airbus Group, large engineering consultancies, and several offshore energy firms. The initiative is now tasked “to accelerate development of Fully Coupled Wave Structure Interaction (FCWSI) modelling suitable for dealing with the latest challenges in offshore and coastal engineering” [J].