Managed retreat
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In the context of coastal erosion, managed retreat allows an area that was not previously exposed to flooding by the sea to become flooded. This process is usually in low lying estuarine areas and almost always involves flooding of land that has at some point in the past been reclaimed from the sea. Managed retreat is often a response to sea level rise, so in the UK has been most common in the southeast of England where the impact of global sea level rise is exacerbated by local subsidence of the land surface isostatic rebound. Managed retreat is now more commonly termed managed realignment. This process can be used to protect areas of land further inland rather than that near the coast. However, in a number of instances managed realignments have occurred or are being planned to compensate for losses of intertidal habitat caused by port development. In the European Union this process is being driven by the Habitats Directive and the Birds Directive (see Natura 2000), while in the USA a similar process has been driven by the Clean Water Act.
In the UK, the first managed retreat site was an area of 0.8 ha at Northey Island in Essex flooded in 1991, followed by larger sites at Tollesbury and Orplands (1995), Freiston Shore (2001) and Abbott's Hall (2002) and a number of others.
[edit] References
The following references review the UK and US experience respectively:
Atkinson, P.W., Crooks, S., Grant, A. and Rehfisch, M. M., 2001. The success of creation and restoration schemes in producing intertidal habitat suitable for waterbirds. English Nature Research Report 425.
Available online in three sections: http://www.english-nature.org.uk/pubs/publication/PDF/ENRR425_1.pdf http://www.english-nature.org.uk/pubs/publication/PDF/ENRR425_2.pdf http://www.english-nature.org.uk/pubs/publication/PDF/ENRR425_3.pdf
Board on Environmental Studies and Toxicology, 2001. Compensating for Wetland Losses Under the Clean Water Act. http://darwin.nap.edu/books/0309074320/html
