About Northey Island:
Northey Island is a remote island in the Blackwater Estuary in Essex owned and cared for by the National Trust. It’s the single largest continuous block of saltmarsh in the estuary and has been at the forefront of coastal adaptation for the past 30 years.
The island is the oldest recorded battlefield as the site of the Battle of Maldon in AD991. Today it is a peaceful haven for wildlife with large number of waders and wildfowl flocking to feed and nest on the island. It’s one of the few places in the UK where dark-bellied Brent geese can be found as well as redshank, curlew and plovers find shelter on the island during winter months.
Northey Island is open to the public between April and October and can only be accessed via a causeway at low tide. A circular walking route allows visitors to enjoy the tranquillity of the estuary and the wildlife that make it their home. It is highly designated as a Site of Special Scientific Interest (SSSI), Special Protection Area (SPA), Ramsar, Special Area of Conservation (SAC) and Marine Conservation Zone (MCZ).
Northey Island is one of the few places in the UK where dark-bellied geese can be found. Photo: @National Trust images - Justin Minns
What is saltmarsh and why do we need to protect it?
Saltmarsh is an area of wetland that lies between land and the sea, which is frequently flooded and drained by tidal water. It provides a vital habitat for a huge range of animals and plants that have adapted to live in the salty water, but also offers a range of environmental benefits such as natural flood management, reducing tidal energy and locking away carbon.
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.
It’s estimated that without action, nearly all the saltmarsh on the island would be lost in the next 100 years.
Saltmarsh at Northey Island. Photo: @National Trust, Justin Minns
What are we doing to protect it?
For the past 30 years we’ve been working to strengthen and improve the saltmarsh habitat at Northey Island. In 1991, the Island was the first place in England to implement the process of managed realignment, a technique which is now used throughout the UK.
Managed realignment involves removing parts of a bank to give space for the rising sea level and space for the saltmarsh plants to migrate inland in a natural way as the sea level rises.
New creeks and lagoons created as part of the managed realignment work on Northey Island. Photo: @National Trust, Justin Minns
What we’ve done so far:
- 1991: The UK’s first ever ‘managed realignment’ scheme was implemented to create over 5,000 hectares of new inter-tidal saltmarsh.
- 2016 to 2024 – we used 11,000 m3 of dredged sediment to improve and existing sea bank and raise the level of saltmarsh in the northwest area of the island
- 2019 – The south embankment was lowered to create area for saltmarsh and a short length of closing bank was constructed
- 2021 – Two new closing banks were created along with a new freshwater pond and a scrape.
- 2022 – a colony of water voles were translocated to a new freshwater pond as their existing pond was of poor quality and being contaminated with salty sea water.
- 2022 - Telegraph poles were removed and cables placed underground as part of preparation for the realignment resulting in record number of dark-bellied Brent geese and dunlins and recorded on the island
- 2023 – 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, creating 10 hectares of saltmarsh habitat.
Since 1991, in total we have created, strengthened or restored more than five hectares of healthy saltmarsh habitat which is now thriving with wildlife. Rare plants such as shrubby sea blite and golden samphire are now flourishing and large number of birds including shelduck, oystercatcher, redshank, dunlin and brent geese can be seen on the island.
Nationally scarce Golden Samphire that is found growing in the saltmarsh at Northey Island. Photo: @National Trust, John Mille
What's next?
We plan to create a new island of the eastern side of the island using three redundant Thames Lighters. This project will have two major benefits:
1- The first is to provide new bird nesting habitat that would otherwise be lost due to rising sea levels.
2- The second major benefit is to strengthen the existing saltmarsh habitat which will be sheltered by the creation of the new island.
This ambitious project will take place in three stages:
Phase one – approximately 2,010 m3 of gravel (34 barges) will be dredged from Maldon Harbour and be placed on the estuary bed on the eastern side of the island and shaped into a raised platform
Phase two - three redundant Thames Lighters will be tugged and carefully placed onto the raised platform. The lighters will be scuttled and infilled with approximately 1,670 m3 of dredged mud.
Phase three – the lighters will be allowed to settle before a further 5,730m3 of mud (approximately 88 barge) are placed and shaped to cover the lighters then topped with approximately 185 m3 of gravel (approximately 3 barge) to infill the coamings and give a final shape of the island.
Once completed the top of the island will rise above the highest tides providing approximately 400m2 of new habitat for a wide range of marine birds and create 15m2 of important saltmarsh habitat.
Cross-Section of Eastern bird Island based on the drawings
Benefit to climate change - carbon Sequestration:
Saltmarsh habitat is one of the biggest carbon lock-ups in the marine environments. It’s estimated that the existing 92 hectares of intertidal saltmarshes at Northey are storing greenhouse gasses at a rate of 262.2 tonnes of CO2 each year. The project will create 15 hectares of new saltmarsh sequestering and additional 42.8 tonnes each year with more recent estimates suggest this could be as high as 119.5 tonnes per year.
Reducing tidal energy
Healthy saltmarsh also helps to reduce the energy from incoming tides therefore reducing the levels on erosion and coastal flooding in the estuary.
Benefit to wildlife
The innovative project will create approximately 400m2 of new habitat for nesting birds, roughly equivalent to the size of a basketball court. The new island will provide a safe, quiet place for birds to nest away from human disturbance where existing bird habitat in the estuary is being lost due to rising sea levels. It’s expected that birds such as curlew, swift, shelduck and oystercatchers, which are on the Birds of Conservation Concern Red and amber List, will start to use the island soon.
Connecting people with nature
We’re keen to raise awareness of
Public engagement is one the important elements of this project. A recent art project saw 127 people attend workshop and walks on the island to discover more about the history and wildlife and the work we are doing on the island. We want to continue this engagement this regular rangers walk to provide a great insight into our ongoing conservation efforts. A dedicated team of volunteers play a vital role in helping us carry out our work and monitor the wildlife that live there.
Northey Island is only accessible at low tide via a tidal causeway. Photo: @ National Trust, Justin Minns
Who we are?
The National Trust is Europe’s biggest conservation charity. We look after nature, beauty and history for everyone to enjoy. The nature and climate emergencies are the biggest threat to our natural and cultural heritage. The organisation pays a special attention to coasts and marine issues emerging as a result of climate change and sea level rise. To achieve this, coastal steering groups are established as a high-level governing body to form the strategies for specific projects at different coasts in the National Trust. Projects are determined as part of coastal adaptation strategies that are approved to meet organisational commitments and goals to protect coastal habitats and endangered wildlife species.
Healthy saltmarsh created during 1991 works which will join up with the new area of saltmarsh created by lowering the sea embankment
Why do we need your help?
Work is already underway, but we aim to accelerate our conservation efforts with your help. Additional funding will complement the National Trust’s internal resources, enabling us to proceed with the second and third phases of the project, as well as ongoing monitoring and documentation efforts.
Phase 2 – Transport and scuttle Thames Lighters, infill with mud and top coamings with gravel (March 2025 – Nov 2025): £40,000
Phase 3 – Final formation of Eastern bird island (Nov 2025 – March 2026): £52,640
Drone monitoring survey will be conducted after the implementation of works to ensure the quality of work: £6000
Documentation and stakeholder engagement: filming the process of establishing the bird island and holding public events for public awareness raising: £6,000.