Tollesbury realignment site - summary

Tollesbury lies within the Essex Coast and Estuaries CHaMP. It is situated on the north shore of the Blackwater Estuary and covers an area of some 21ha. It is one of the first 'relatively' large scale (for the UK) experimental managed realignment schemes. In this case the scheme has been initiated to better understand the development and effect of a managed realignment site, rather than for sea defence purposes as at Orplands. As such it has been carefully monitored in relation to the development of saltmarsh, including the value of pre-treatment and post-treatment and includes standardised bird monitoring. [Date of breaching August 1995.]

Caption: The Tollesbury realignment site near high tide, December 2000. Note the drowned hedgerow trees.

Comment: The coming years may see the development of saltmarsh and of a creek system draining the marsh and mudflat as accretion of sediments raises the surfaces in the areas below 1.5m ODN to elevations suitable for plant growth. Alternatively changes in the sediment supply or failure to develop an adequate drainage system may produce a long-standing water-logged mudflat low in the tidal frame and fringed by relatively static saltmarsh vegetation. These alternative states have quite different consequences for the exploitation of the site by fish and birds. Although the lower areas had not colonised after 7 years of tidal influence, monitoring data shows that considerable accretion has taking place within the lower areas. It is predicted that, as surface levels rise, colonisation by saltmarsh vegetation will take place. By October 2002 when the above photograph was taken the vegetation growth appeared to have consolidated, rather than expanding laterally.