Friday, January 15, 2010

Retreat, attack or defend? Engineers and architects weigh options for coastal cities

Sam Bond in Flooding is a growing problem for the UK's coastal towns and cities as rising sea levels and man-made constraints conspire to increase the risk of inundation. A joint report from the Institute of Civil Engineers (ICE) and RIBA spin-off building future attempts to spark a wider debate by using military metaphor to look at the three broad options - retreat, defend or attack.

Pulling back from the coastline and estuaries to avoid catastrophe is one option, says the report, making a distinction between a managed retreat and abandonment. Under this option, settlements would move critical infrastructure and housing away from the water's edge and have soft flood defences that would allow water into previously-protected areas.

The advantages of such solutions are long-term sustainability and cost savings, but of course there are down sides as well - investment in property and infrastructure would be lost and there are real difficulties translating much of this from the drawing board to reality - is it possible to relocate residential areas, for example?

The next option addressed by the report is that of building bigger and better flood defences. The report questions the practicality of trying to maintain the status quo in a changing environment. "Many of the hard engineered defences of the 20th century have been criticised for being unsustainable, reducing access to water, damaging to coastal habitats and costly to maintain and improve," it says. "However, they have provided protection and reduced risk from flooding, allowing activities to go on uninterrupted in the built environment."

It suggests that some of the problems might be averted by taking an over-arching view of the problem, rather than addressing localized issues piecemeal….

The Cobb in the harbor at Lyme Regis, England, shot by Joadl, Wikimedia Commons, under the terms of the GNU Free Documentation License, Version 1.2

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