Remote Essex island ‘lets the sea in’ to create new saltmarsh in fight against climate change

Healthy saltmarsh is one of the largest carbon lock-ups in the marine environment, but rising sea levels and climate change are causing this vital habitat to become eroded with 85% of the UK’s saltmarsh lost since the mid-1800s.

Northey Island, which is cared for by the National Trust, is the largest single block of saltmarsh habitat in the Blackwater Estuary and has been at the forefront of coastal adaptation for the last 30 years.

Since 2020, the Trust has been undertaking the biggest habitat creation project in the island’s history to help the area better withstand climate impacts. Earlier in the year a 40-metre section of embankment was lowered and a further 200-metre section removed to allow the sea to flood an area in the east of the island. Over time, high tides will deposit seeds and sediment creating approximately 10 hectares of new saltmarsh and, along with other coastal adaptation works carried out on the island, protecting a further 60 hectares of saltmarsh around the island for future generations.

Daniel Leggett, Coastal Project Manager for the National Trust said ‘Northey Island is really feeling the effects of climate impacts – without concerted action, the projected rate of habitat loss for the next 100 years would be very dramatic indeed, with nearly all of the saltmarsh predicted to be lost. And the whole island and estuary would be much worse off for it. The action we’ve taken here on such a large scale means that future generations, wildlife, and our climate will benefit from this unusual and unsung habitat sitting between the land and the sea.

Daniel continues: “Our work over the last 30 years is a demonstration of coastal adaptation that is now benefitting other coastal sites around the UK. We’re facing a climate and nature crisis, and we must all act now to reduce loss of habitats, bring back wildlife, and adapt to future conditions in a way that will last the test of time. We’re proud that what we’ve learnt is being shared and implemented elsewhere.”

Carrying out major work on such a remote site has also had its challenges, as the island is only accessible at low tide via a tidal causeway.

Russell Clement, General Manager for the National Trust Essex and Suffolk Coast said “Northey Island is one of the few places in the UK where dark-bellied brent geese can be found, so it’s vital that their habitats have remained undisturbed by the work. It’s been a huge engineering project and involved years of planning. Working around the tide meant that working hours were limited and we had the delicate task of large machinery manoeuvring along the existing sea wall to move over 1,000 cubic metres of soil.”

As well as making the island more resilient to climate change, the work has many benefits for wildlife. Preparation included removing telegraph poles and overhead power lines and placing these cables underground, which has opened up the sky for birds to land. Since then, record numbers of birds have been recorded including dunlins and dark-bellied brent geese, both protected species at risk of decline.

The new area of saltmarsh will also offer great new habitats for plants like including the nationally scarce shrubby sea-blite, golden samphire and bladder rack.

A series of new wildlife ponds have also been created and a colony of water voles was relocated from a pond that was frequently flooded by tidal water to a new purpose-built freshwater pond.

Further work is planned on other areas of the island to improve habitats for birds and other wildlife that live in the Blackwater Estuary, including a new nesting island for birds that will also protect existing saltmarsh from the rising sea level and erosion by tidal waves.

Northey Island is open to the public between April and October and as part of the work a new viewing platform and hide have been installed so visitors can enjoy the tranquil landscape and the wildlife that make their home on the island.