Coastal Change: Titchwell Marsh, Norfolk

Titchwell Marsh is one of the RSPB’s most important nature reserves. The freshwater reed bed is home to three of the country’s rarest breeding birds; the bearded tit, marsh harrier and bittern.

The freshwater habitats are vulnerable to flooding by the sea and the Titchwell Coastal Change Project involves building a stronger sea defence to the north of the reserve and widening and strengthening the existing defences to the west and east. The improved defences will help to protect the reserve for at least the next fifty years.

RSA Geotechnics was commissioned to carry out a ground investigation under the directions of the consulting engineer for the project BTP Hyder. The fieldwork comprised the drilling of a number of light-cable percussion and window sample boreholes and machine excavated trial pits all with challenging access problems. The site investigation was carried out in order to provide geotechnical parameters for use in the design and construction of a managed realignment scheme.

Managed realignment is the deliberate process of altering and engineering the flood defences to allow the controlled flooding of an area behind the current flood defence. By managing this process, the hope is to prevent damage to key habitats that could occur if coastal erosion was left to its own devices. This type of realignment scheme will also be required elsewhere around the country’s threatened coast.

The entire project took several years to plan and three years to complete because the construction work could only be carried out between mid-July and October each year. In spring and early summer rare breeding species could not be disturbed and in winter, wading birds, ducks and geese use the reserve as a safe feeding and roosting area.

The completed project has helped to protect and improve the conservation value of the reserve and has ensured that Titchwell Marsh will remain one of the most outstanding and valuable wildlife sites in Europe.