FACING UP TO RISING SEA LEVELS: RETREAT, DEFEND, ATTACK?

15 January 2010: Retreating inland, creating habitable defence structures and building out into the sea are three options proposed to cope with the extremities of rising sea levels, in a futuristic project released today by the Royal Institute of British Architects’ (RIBA) think tank Building Futures and the Institution of Civil Engineers (ICE).

The think-piece facing up to rising Sea Levels: Retreat, Defend, Attack? warns that the future of our coastal cities is in jeopardy due to rising sea levels, sinking landmasses and an increase in storm frequency. 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, proposing different solutions based around three realistic briefings:

• Retreat (or managed realignment) – rising sea levels have reduced landmass. Hard engineering defences are no longer sustainable or affordable. Moving the line of defence inland, allowing flood water to occupy previously protected city areas is the only option.
• Defend - there is a growing deficit on flood defences which public funding is not covering, but the benefits of preventing water entering the existing cities still outweigh the costs. Flood defence systems must be made commercially viable to attract private investment.
• Attack – the population of the UK has increased significantly, meaning building out into the water, via stilted and floating structures, is an attractive option to alleviate pressure inland. This has been proven successful overseas and due to high demand for space the public and private sector are both willing to invest in expanding seaward.

RIBA President Ruth Reed said:

The scenarios we have created are extreme, but it is an extreme threat we are facing. Approximately 10 million people live in flood risk areas in England and Wales, with 2.6m 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’.”

The report urges Government, built environment professionals, planning authorities and the public to focus on tackling the man-made obstacles that currently prevent such solutions being made a reality.

Chair of the ICE steering group Ben Hamer said: “A proactive and united, almost war-like approach is needed if we are to win the battle against what is set to be our biggest challenge in the next century, the ‘water invasion’.

Some very difficult decisions need to be made in the near future, and to do this we need integrated thinking. The UK must urgently change the way it plans, builds and designs at-risk communities.

This requires a strategic vision at local and national level, more co-ordination and improved communication between stakeholders, and some very creative thinking about how solutions can be developed to be financially sustainable.”

The scenarios were master-minded by a group of top architects, civil engineers, city designers, planners, developers, policy-makers, ecologists and futurologists.

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 15^th - 27th February and Kingston upon Hull 15^th – 28th April.

The report can be downloaded at http://www.ice.org.uk/downloads/Facing Up to Rising Sea Levels Document Final.pdf.

EDITOR:

High resolution images of the six scenarios – Hull Retreats, Hull Defends, Hull Attacks and Portsmouth Retreats, Portsmouth Defends, Portsmouth Attacks – are available for download here http://fts.rca.ac.uk/download/?u=Claire.Jamieson&k=moy5xuyu.   

Detailed summaries of the scenarios and flooding fast facts are included in additional information below.

Launch event: Media are invited to attend the launch event 8.30am – 10.30 am, 14^th January at the Building Centre, London, WC1E 7BT.

Ends

Media contacts:

Emily Beadon,
ICE Media Relations,
t: 020 7665 2261,
e: emily.beadon@ice.org.uk

Mina Vadon,
RIBA Press Officer,
t: 020 7307 3761
e: mina.vadon@inst.riba.org

ADDITIONAL INFORMATION

SCENARIOS

1. Kingston-Upon-Hull sits 25 miles from the North Sea on the north bank of the tidal Humber Estuary. It is bisected by the River Hull, which is liable to flooding. To make matters worse, the city is very flat and low-lying and consequently has to be constantly drained by pumps. The port is of national strategic importance.  

Retreats

In 2010 a radical planning policy was adopted, and the majority of the city of Hull retreated East and West, out of harm’s way. The old city, now an island, was defended as it was deemd to have significant assets and is now linked to the retreated community by several bridges. Compensation packages for the relocated community were part-funded by savings made by not building and maintaining new flood defenses. In 2080 the new settling was branded New Hull, promoting tourism and investment.

Hull Defends

With 90 percent of the city at risk of flooding, defending from sea-level rise as well as the threat from the River Hull requires extensive investment. The defense strategy is incorporated into a commercial development, with a series of reservoirs built behind a new outer wall. The reservoirs were designed to allow for development on top of the walls, which also helped offset the cost of the construction of the new defenses. 

Hull Attacks

Disused marine infrastructure was recycled and used to create a water community around the port. A decommissioned North Sea oil rig was used as the re-commissioning platform for other rigs. The network of static platforms and floating structures was developed into a mix of residential, recreational and commercial ’land’. The functional floodplain to the north-east was inhabited by floating communities of houseboats. The remaining city was gradually adapted to cope with increased flooding.

1. Portsmouth

The city of Portsmouth is located on Portsea Island on the south coast of England. It is densely populated and surrounded by water on all sides, leaving it extremely vulnerable to tidal flooding.

Portsmouth Retreats

In 2010 the fringes of the east of the island were planned for salt marsh restoration, and this was fully formed in 20 years, providing a recreational area boasting diverse wildlife. New hillside terrace developments were built further into the centre of the island, and buildings remaining on the edges found new uses more appropriate to flood risk. Residential houses were adapted, with dwelling moved to top floors and access routes repositioned above ground level.

Portsmouth Defends

The total line of defense was reduced by building new tide gates to the harbour, which can be closed when a tidal surge is predicated. Marine traffic was reduced by relocating regular routes. This means there is no need to defend the inner harbour, representing a massive saving in defence infrastructure investment. A new ’living wall’ was built for the outer coastline, with the potential for commercial, residential and recreational development. Developers pitched for segments to develop, but also maintain. 

Portsmouth Attacks

In 2010 a scheme was drawn up for two-tiered large piers to emerge from the city, linking into existing infrastructure and proving residential, commercial and recreational spaces. The lower tiers were used for traffic. Existing buildings on the island were retro-fitted to adapt to the flood risk, and new developments were built with regular high levels of water in mind. This included stilted and floating communties.  

FLOODING FAST FACTS

• The length of the UK coastline is around 12,429 km or 7723 miles, compared to the coastline of Italy (7,600 km), Spain (4,964 km), France (3,427 km) or The Netherlands (451 km)
• Home insurance firms are set to lose £4 billion a year by 2035 on repairing flood water damage.
• Annual flood defense spending must be increased to a minimum of £750m (currently c. £500m) just to maintain design-specification levels of protection.
• Around 10 million people, in 5.5 million properties, live in flood risk areas in England and Wales, with 2.6m of those properties at direct risk of flooding from rivers or the sea.
• In England the cost of claims from flooding in June and July 2007 exceeded £3.5bn.
• In January 1953, over 300 people died and over 24,000 homes were flooded on the east coast of England after flood defenses were breached as a consequence of extremely high winds and a tide at dangerous levels.
• In Hull, after 100mm of rain fell in 24 hours in the summer of 2007, 600 streets, nearly 9000 homes and 91 of the city’s 99 schools were flooded. 1300 businesses were affected.

Notes to editors:

• Building Futures is the RIBA’s think tank on issues affecting the future of the built environment. It was established to create space for discussion about the needs of society from our built environment and, consequently, the built environment professions in 20 years and beyond. The group aims to highlight and promote those working with new technologies and developing new ideas, which will contribute to the future of our towns and cities and address society’s changing demands over the coming years. The Building Futures programme is ongoing and includes exhibitions, debates, events and research activities. For more information visit .
• The Institution of Civil Engineers (ICE) was founded in 1818 to ensure professionalism in civil engineering. It represents 80,000 qualified and student civil engineers in the UK and across the globe. The ICE has long worked with the government of the day to help it to achieve its objectives, and has worked with industry to ensure that construction and civil engineering remain major contributors to the UK economy and UK exports.