Crossing the Thames Barrier: Adaptive Reuse of Existing Infrastructure under Climate Change

The capital city of the United Kingdom, London, is situated on low-lying land around the river Thames, leaving it vulnerable to surge tides entering the Thames estuary via the North Sea. These tides can be deadly–most notably, in
1953, over 300 died in a resulting flood, and thousands were made homeless. In response to this event new flood-control measures and defences were implemented and designed, the keystone of which was the new Thames Barrier,
completed in 1984. It is the world’s second largest movable flood barrier, and protects the floodplain of most of Greater London–on which over 1.25 million people live.

However, even enormous pieces of infrastructure have expiration dates. The Barrier was designed to protect London from a one-in-a-thousand combined surge event until 2030. While with adequate modification and maintenance it should continue to provide protection to London past that date, the standard of this protection will decline over time. More worryingly, the Environment Agency has stated that the number of closures the Barrier had made on the river has risen dramatically from the 1980s to the present day. The gates were closed over 40 times in 2013 alone. These circumstances prompted the Environment Agency to launch the Thames Estuary 2100 project to develop management plans for the region to last to the end of the twenty-first century. Climate change was stated as a key reason for the prediction that the Barrier will no longer be adequate past 2030. Under this plan, a new downstream barrier has been designed to be built at Long Reach, in Dartford, to replace it.

However, Derrick Leong On U has written an award-winning master’s thesis to argue that improving and changing the use of the present Barrier in 2050 is a more sustainable solution than merely replacing it when it expires. Challenging conventional adaptive reuse practice, he considers more ambitious architectural interventions, such as dismantling and reconstituting the parts of the current Barrier to extend its lifetime as a piece of public infrastructure. Highlighting the lack of direct transportation between Silvertown in the London Borough of Newham and Charlton in the Royal Borough of Greenwich, to be developed as London’s third CBD (after Central London and Canary Wharf), Leong has proposed in his thesis that the expired Barrier be reconstituted as a multi-use ‘Centre of Climate Change’. Combining function and utility with a pedestrian concourse connecting the two sides of the Thames, a treatment facility could include a waste-to-energy plant for non-recyclable waste and a community recycling workshop. His plan also includes a Museum that reminds the public of the impact of global climate change.

Leong splits the Barrier into four divided sections – first, the Entrance Hall, an informative exhibit of the Treatment Facility. Second, the Underwater Concourse allows the public to pass through the existing Barrier structure, while a Main Concourse, situated at the exact Mean Low Water Springs (MLWS) level, allows the public to experience tidal water level difference in a different way. Finally, an Atrium formed by the renovation of existing engineering components serving as a main space for environmental exhibitions. Leong’s thesis is grounded in the importance
of sustainability and community in the reconfiguration of public infrastructure.

Student Name: Derrick Leong On U
School: School of Architecture, Chinese University of Hong Kong
Instructors: Professor Nelson Chan
Project Name: Crossing the Thames Barrier: Adaptive Reuse of Existing Infrastructure under Climate Change (March Thesis, 2018)
Location: London, United Kingdom
Awards: Best Thesis Project 2018, School of Architecture, Chinese University of Hong Kong