National Trust Sinks Barges to Create Bird Island in Essex Estuary

The National Trust has carried out a marine engineering project in the Blackwater Estuary, Essex, by sinking three former Thames lighter barges to establish a new island for bird habitats.

This development forms part of ongoing coastal adaptation work at Northey Island, which has included managed realignment and saltmarsh restoration over the past three decades. The initiative aims to provide additional roosting and nesting space for several bird species identified as red-listed or vulnerable.

Specialist contractors prepared the barges by cleaning and making them seaworthy, then towed them to the designated site in the estuary. After positioning, holes were cut in the hulls to allow the barges to sink, and they were subsequently filled with sediment and topped with gravel to ensure they remain above the highest tide levels.

The barges, each measuring between 20 and 32 metres in length, were originally used to transport materials such as coal, building supplies, and food from the Port of London. Their repurposing for the project involved significant preparation and logistical planning.

What the numbers show

• Three barges were used to form the new island
• Up to 8,000 cubic metres of sediment was applied
• The island will cover about 0.55 hectares (1.4 acres

Once completed, the new island will offer approximately 0.55 hectares of habitat, which is nearly the size of a football pitch. This area is designed to provide a refuge for bird species such as dunlin, curlew, lapwing, ringed plover, little terns, and avocets.

The project involved using a volume of sediment equivalent to more than three Olympic swimming pools to fill and surround the sunken barges. This approach was intended to create stable ground above the highest water levels in the estuary.

The National Trust stated that the project represents a continuation of its coastal adaptation efforts, which have been ongoing at Northey Island for over 30 years. These efforts have focused on responding to changes in the coastal environment and supporting wildlife.

In a company statement, the National Trust described the initiative as “a bold marine engineering feat.” The organisation confirmed that the new habitat will serve as a roosting and nesting site for a range of bird species considered at risk.

* This article is based on publicly available information at the time of writing.