When Lloyd’s examined the threat posed by coastal flooding in its 360 Risk Insight Report Coastal Communities & Climate Change: Managing Future Insurability, a key finding was that society will need to be flexible enough to take account of the uncertainties surrounding rising sea levels.
Now a forward thinking report released by the Royal Institute of British Architects’ (RIBA) think tank, Building Futures, and the Institution of Civil Engineers (ICE) has outlined three radical options: retreating inland, creating habitable defence structures and building out into the sea.
The report Facing up to Rising Sea Levels: Retreat, Defend, Attack? warns that the future of the UK’s coastal cities is in jeopardy due to rising sea levels, sinking landmasses and an increase in storm frequency. It argues that with over 12,000 km of coastline radical thinking is urgently needed to protect the UK’s at-risk communities from extreme flooding.
Focusing on Kingston upon Hull and Portsmouth, two of the UK’s highest flood risk areas, the research presents six scenarios set up to 90 years in the future. The proposed solutions are breathtaking, but are based on realistic briefings.
One envisages Hull adopting a radical planning policy whereby the majority of the city of Hull retreats east and west, out of harm’s way. Under the scenario the old city, now an island, is defended as it is deemed to have significant assets and it is linked to the retreated community by several bridges. Compensation packages for the relocated community are part-funded by the savings made by not building and maintaining new flood defences. In 2080 the new settlement is branded New Hull, promoting tourism and investment.
In a similarly bold scenario for Portsmouth, two-tiered large piers emerge from the city, linking into existing infrastructure and providing residential, commercial and recreational spaces. The lower tiers are used for traffic. Existing buildings on the island are retro-fitted to adapt to the flood risk, and new developments are built with regular high levels of water in mind. This includes stilted and floating communities as seen in other countries.
The report’s authors argue that such solutions are realistic because hard engineering defences may not be sustainable or affordable in the future and because there is a growing deficit on flood defences that public funding is not covering.
RIBA President Ruth Reed said:
“The scenarios we have created are extreme, but it is an extreme threat we are facing. Approximately ten million people live in flood risk areas in England and Wales, with 2.6 million properties directly at risk of flooding from rivers or the sea.
“However, if we act now, we can adapt in such a way that will prevent mass disruption and allow coastal communities to continue to prosper. But the key word is ‘now’,” Reed stressed.
In the summer of 2007, 100mm of rain fell in 24 hours on Hull flooding 600 streets, nearly 9,000 homes and 91 of the city’s 99 schools. Over 1,000 businesses were affected.
In January 1953, over 300 people died and over 24,000 homes were flooded on the east coast of England after flood defences were breached as a consequence of extremely high winds and a tide at dangerous levels.
Recent figures from the Environment Agency show that:
- One in six homes in England is currently at risk of flooding from rivers, the sea, or surface water from overflowing drains.
- More than five million people currently live and work in 2.4 million properties at risk from rivers or the sea -490,000 of which have a significant chance of flooding. The organisation is warning that this figure would rise to 840,000 by 2035 if future investment is maintained at existing levels.
- An additional 2.8 million properties are currently at risk of flooding from surface water. The Environment Agency estimates that an additional £150m a year by 2035 will be required to help mitigate this risk.
- 55% of water treatment works and pumping stations, 14% of electricity infrastructure, 2,358 schools and 2,363 doctors' surgeries in England are situated in flood risk areas, along with some 4,000km of roads and 2,500km of railway.
Sea levels are likely to rise by about 1.4m globally as polar ice melts, according to a major review of climate change in Antarctica conducted by the Scientific Committee on Antarctic Research (SCAR).
Trevor Maynard, Manager of Lloyd’s Emerging Risks team, warns that planners must be ready for worst case scenarios. “Whatever action is taken in response to rising sea levels it is important that plans be robust enough to take account of extreme sea level rises – as much as 2m,” he says.
The full project, including sketches and details of the proposed ‘new cities’, will be exhibited at the Building Centre, London 6th Jan – 29th Jan 2010, before travelling to Portsmouth 15th - 27th February and Kingston upon Hull 15th – 28th April.
