Blackwater and Colne Estuaries

The Blackwater estuary is the largest estuary in Essex and one of the largest estuarine complexes in East Anglia, flowing from Maldon before joining the Colne estuary and the North Sea at Mersea Island. 

The Blackwater and Colne estuaries are of international conservation importance and consist of a mosaic of important habitats including saltmarsh, intertidal mudflats, shingle and coastal grazing marsh.

This map shows the current projects; potential, in progress and completed, for the Blackwater and Colne Estuaries.

Project status




    In progress



Click or tap a number to view the project details



The Native Oyster

The Blackwater, Crouch, Roach and Colne Estuaries contain the most important area in the South-East of England for the Native Oyster (Ostrea edulis) and the extensive oyster bed habitat that they create, made up of the oysters themselves as well as their dead shells.

Essex Wildlife Trust was awarded funding from Natural England in early 2015 to digitise Essex coastal data for the Blackwater and Colne Estuary, collected by the National Rivers Authority in the early 1990s. This is part of our ongoing partnership work with Natural England and the Environment Agency.

Website key stakeholders:

Environment Agency logo      Essex Wildlife Trust logo           ESWT Logo 70

Design by LTD Design Consultants and build by Garganey Consulting based on an original concept by Herts and Middlesex Wildlife Trust