Lowering seawall to protect Suffolk’s only island

Rupert Masefield

Friday 9 November 2018

RSPB reserve, Saltmarsh, Havergate RSPB reserve, England.

Lowering a seawall may seem an odd way to protect a nature reserve from the sea, but that's what the RSPB is doing at Havergate Island with Viridor Credits, the Environment Agency and Defra's Natural Flood Management Programmme.

Work currently underway to lower a 650 metre section of the seawall surrounding Havergate Island by nearly half a meter will enable the RSPB to safeguard the unique Suffolk Coast nature reserve’s habitats against the impact of increasingly frequent storm surges predicted as a result of climate change.

Visiting the island nature reserve in her Suffolk Coastal constituency last week, Environment Minister and Suffolk Coastal MP, Thérèse Coffey said:

“This project to protect Havergate Island is a fine example of Natural Flood Management (NFM) and I’m delighted to see for myself how the works are progressing. Flood defence technology and engineering is improving all the time and the project shows how by using a mix of natural and concrete defences, we can provide the best flood protection for individual areas.

“Suffolk is just one of the areas across England benefitting from our £15m investment in NFM and in the record £2.6billion we are investing overall to better protect against flooding.”

Havergate Island has been an RSPB nature reserve since 1949, after avocets – the iconic pied waders with the slender up-curved bill that have featured on the RSPB’s logo since the 1950s – were found breeding on the island in 1947. Until then, avocets had been extinct as breeding birds in the UK for more than 100 years.

Today, avocets still nest on the island and adjacent RSPB nature reserves, and it has become very important for nesting gulls, terns and large numbers of wintering wildfowl and waders. The island is home to the rare yellow-striped bear spider, starlet sea anemone along with a wealth of rare coastal plants.

In recent years, increasingly frequent tidal storm surges have taken their toll on the island’s habitats and wildlife, damaging the seawall, flooding lagoons and washing away shingle banks.

The solution though has been not to build up the seawalls, but to lower them in places to allow the sea to flow into the lagoons in a controlled way when storms cause unusually high tides.

Aaron Howe, RSPB Sites Manager for the South Suffolk Coast:

“Decreasing the height of the seawall may seem like a counter-intuitive way to protect Havergate Island’s wildlife from the sea, but doing allows us to direct the water into the island’s lagoons when there is a tidal surge before it reaches the point of overwhelming the seawall. This also has the effect of relieving some of the pressure on other seawalls in the estuary during these extremely high tides.”


The work does not stop there. The material generated by lowering the height of the seawall will be used to create a gently sloping bank inside the wall down to the lagoon, which will be sown with native coastal grass-seed. In the lagoon itself, new islands will be created for nesting waders, including avocets.

Aaron Howe:

“This kind of natural flood management means we can keep Havergate Island’s habitats safe at the same time as contributing towards alleviating the impact of future storm surges elsewhere on the estuary. It’s a win-win situation, and the kind of thing I’m sure we will see more of in response to rising sea levels impacting on people and nature on the Suffolk Coast.”


This innovative project has been part-funded by the Environment Agency with a £50,000 grant awarded as part of Defra’s £15m Natural Flood Management Programme, by the Landfill Tax Fund through a £46,990 grant awarded by Viridor Credits, and by the Pamela Matthews Charitable Trust.

The Environment Agency’s Guy Cooper said:

“The work at Havergate is part of efforts to develop our understanding and evidence of adaptation and Natural Flood Management techniques on a dynamic coastline.

“The aim is to find out what techniques work well so that we can consider them alongside future flood and coastal erosion risk management schemes.”

Gareth Williams, Operations Manager at Viridor Credits:

“Controlling the water levels and salinity of these treasured habitats is vital in keeping them healthy. Viridor Credits is pleased to once again work with RSPB in protecting these rare habitats for all wildlife.”

Last Updated: Friday 9 November 2018


Coast on a stormy day

Rupert Masefield

Communications Manager, England Policy & Advocacy

07872 814878
Tagged with: Country: England Topic: Birds and wildlife Topic: Climate change Topic: Conservation Topic: Habitat conservation Topic: Marine and water Topic: Reserves Topic: Site conservation Topic: Water and wetlands